WO2024215645A2 - Système d'imagerie basé sur un guide d'ondes pour suivi d'objet et système d'affichage basé sur un guide d'ondes pour réduire un fantôme côté monde - Google Patents

Système d'imagerie basé sur un guide d'ondes pour suivi d'objet et système d'affichage basé sur un guide d'ondes pour réduire un fantôme côté monde Download PDF

Info

Publication number
WO2024215645A2
WO2024215645A2 PCT/US2024/023681 US2024023681W WO2024215645A2 WO 2024215645 A2 WO2024215645 A2 WO 2024215645A2 US 2024023681 W US2024023681 W US 2024023681W WO 2024215645 A2 WO2024215645 A2 WO 2024215645A2
Authority
WO
WIPO (PCT)
Prior art keywords
waveguide
light
coupling element
eye
real
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2024/023681
Other languages
English (en)
Other versions
WO2024215645A3 (fr
Inventor
Wanli Chi
Xiang Li
Jian Xu
Miaomiao XU
Xingzhou TU
Shaobai LI
Xiayu FENG
Wai Sze Tiffany Lam
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Meta Platforms Technologies LLC
Original Assignee
Meta Platforms Technologies LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US18/608,831 external-priority patent/US12681298B2/en
Application filed by Meta Platforms Technologies LLC filed Critical Meta Platforms Technologies LLC
Publication of WO2024215645A2 publication Critical patent/WO2024215645A2/fr
Publication of WO2024215645A3 publication Critical patent/WO2024215645A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/011—Arrangements for interaction with the human body, e.g. for user immersion in virtual reality
    • G06F3/013—Eye tracking input arrangements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0093—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B27/0172—Head mounted characterised by optical features

Definitions

  • the present disclosure relates generally to optical systems and, more specifically, to a waveguide based imaging system for object tracking, and a waveguide based display system for reducing a world side ghost.
  • An artificial reality system such as a head-mounted display (‘’HMD”) or heads-up display (“HUD”) system, generally includes anear-eye display (“NED”) system in the form of a headset or a pair of glasses configured to present content to a user via an electronic or optical display within, for example, about 10-20 mm in front of the eyes of a user.
  • the NED system may display virtual objects or combine images of real objects with virtual objects, as in virtual reality (“VR”), augmented reality (“AR”), or mixed reality 7 (“MR”) applications.
  • Object tracking devices such as devices for tracking eyes and/or faces, have been implemented in a variety of technical fields, e.g., HUDs, HMDs, smart phones, laptops, televisions, vehicles, etc.
  • object tracking devices have been implemented in AR, VR, and/or MR applications.
  • a three-dimensional (“3D”) head pose, facial expressions, pupil positions, and eye gazes of the user may be tracked in real time, which can be used for various purposes, including, for example, adjusting display of content to the user, monitoring user’s attention, physical and/or psychological status, etc.
  • an AR or MR system a user may view both images of virtual objects (e.g., computer-generated images (“CGIs”)) and the surrounding environment by, for example, seeing through transparent display glasses or lenses.
  • virtual objects e.g., computer-generated images (“CGIs”)
  • CGIs computer-generated images
  • One example of an AR system may include a pupil-expansion waveguide display system, in which an image light representing a CGI may be coupled into a waveguide, propagate within the waveguide via totally internal reflection, and be coupled out of the waveguide at different locations to expand an effective pupil.
  • the waveguide may also combine the image light representing the CGI and a light from a real-world environment, such that the virtual image may be superimposed with real- world images.
  • the pupil-expansion waveguide display system may potentially offer an eyeglass form factor, a large field of view, a large effective pupil area, a small thickness, and a light weight.
  • One aspect of the present disclosure provides a system comprising: a light source configured to emit a infrared (IR”) light for illuminating an object; and a waveguide imaging assembly including a waveguide, an in-coupling element disposed at a first portion of the waveguide, an out-coupling element disposed at a second portion of the waveguide, and an optical sensor disposed facing the out-coupling element; wherein the in-coupling element is configured to couple the IR light reflected by the object into the waveguide, the waveguide is configured to guide the IR light to propagate toward the out-coupling element through total internal reflection, and the out-coupling element is configured to couple the IR light out of the waveguide toward the optical sensor; and wherein the optical sensor is configured to generate a tracking signal of the object based on the IR light output from the waveguide.
  • IR infrared
  • the in-coupling element and the out-coupling element are configured to deflect the IR light, and substantially transmit, with negligible deflection, a visible light.
  • the waveguide is configured to guide the IR light to propagate toward the out-coupling element along a width direction of the waveguide via total internal reflection; and, along the width direction of the waveguide, a width of the incoupling element is configured to be at a sub-millimeter level.
  • the width of the in-coupling element is configured to be 200-300 micrometers, 300-400 micrometers, 400-500 micrometers, or 500-600 micrometers. [0008] In some embodiments, wherein the optical sensor is disposed off-axis with respect to the object.
  • At least one of the in-coupling element or the out-coupling element includes a diffraction grating.
  • the in-coupling element is a first in-coupling element
  • the out-coupling element is a first out-coupling element
  • the system further comprises: a second in-coupling element disposed at the second portion of the waveguide; and a second out-coupling element disposed at the first portion of the waveguide; wherein the second incoupling element and the second out-coupling element are configured to deflect a visible light, and substantially transmit, with negligible deflection, the IR light.
  • the second in-coupling element is configured to couple the visible light representing a virtual image into the waveguide as an in-coupled visible light that propagates inside the waveguide via total internal reflection; and the second out-coupling element is configured to couple the in-coupled visible light out of the waveguide as one or more output visible lights toward an eye-box region of the system.
  • a width of the first in-coupling element is smaller than a width of the second out-coupling element.
  • the light source is a first light source
  • the system further comprises: a second light source disposed facing the second portion of the waveguide, and configured to output the visible light toward the second in-coupling element.
  • the in-coupling element is a first in-coupling element
  • the out-coupling element is a first out-coupling element
  • the waveguide is a first waveguide
  • the system further comprises: a second waveguide stacked with the first waveguide; a second out-coupling element disposed at a first portion of the second waveguide; and a second incoupling element disposed at a second portion of the second waveguide; wherein the second in-coupling element and the second out-coupling element are configured to deflect a visible light, and substantially transmit, with negligible deflection, the IR light.
  • the second in-coupling element is configured to couple the visible light representing a virtual image into the second waveguide as an in-coupled visible light that propagates inside the second waveguide via total internal reflection; and the second out-coupling element is configured to couple the in-coupled visible light out of the second waveguide as one or more output visible lights toward an eye-box region of the system.
  • a width of the first in-coupling element is smaller than a width of the second out-coupling element.
  • the light source is a first light source
  • the system further comprises: a second light source disposed facing the second portion of the second waveguide, and configured to output the visible light toward the second in-coupling element
  • the optical sensor and the object are disposed at the same side of the waveguide, or at different sides of the waveguide.
  • a device comprising: a waveguide configured to guide an image light to propagate inside the waveguide via total internal reflection (“TIR”); an array of first mirrors embedded inside a first portion of the waveguide, and configured to split the image light into a plurality of redirected image lights propagating inside the waveguide; an array of second mirrors embedded inside a second portion of the waveguide, and configured to couple the redirected image lights out of the waveguide as a plurality of output image lights; and an optical filter disposed at a surface of the waveguide and at least partially overlapping with the first portion of the waveguide: wherein the optical filter is configured to deflect a light from a real-world environment incident onto the optical filter at an incidence angle greater than or equal to a predetermined angle back to the real-world environment.
  • TIR total internal reflection
  • the light from the real-world environment incident onto the optical filter at the incidence angle greater than or equal to the predetermined angle is a first light having a first incidence angle
  • the optical filter is configured to: transmit a second light from the real-world environment incident onto the optical filter at a second incidence angle less than the predetermined angle toward the first mirrors.
  • the optical filter does not overlap with the second portion of the waveguide.
  • the optical filter includes a volume Bragg grating, and the volume Bragg grating is a multiplexed volume Bragg grating having a plurality of different grating periods.
  • a device comprising: a waveguide configured to guide an image light to propagate inside the waveguide via total internal reflection (“TIR”); an array of folding mirrors embedded inside the waveguide, and configured to split the image light into a plurality of redirected image lights propagating inside the waveguide; and an array of out-coupling mirrors embedded inside the waveguide, and configured to couple the redirected image lights out of the waveguide as a plurality of output image lights; wherein each folding mirror has a first surface facing the real-world environment and a second surface facing an eye-box region of the device, and the folding mirror is configured to substantially transmit a light from a real-world environment incident onto the second surface of the folding mirror at an incidence angle greater than or equal to a predetermined angle.
  • TIR total internal reflection
  • FIGs. 1A-1C illustrate schematic diagrams of a conventional eye tracking system used in an artificial reality device
  • FIGs. 2A-2C illustrate schematic diagrams of an object tracking system, according to an embodiment of the present disclosure
  • FIG. 3 A illustrates a schematic diagram of an object tracking system, according to an embodiment of the present disclosure
  • FIG. 3B illustrates a schematic diagram of an object tracking system, according to an embodiment of the present disclosure
  • FIG. 4A illustrates a schematic diagram of an optical system including a display assembly and an eye tracking assembly, according to an embodiment of the present disclosure
  • FIG. 4B illustrates a schematic diagram of an optical system including a display assembly and an eye tracking assembly, according to an embodiment of the present disclosure
  • FIG. 4C illustrates a schematic diagram of an optical system including a display assembly and an eye tracking assembly, according to an embodiment of the present disclosure
  • FIG. 5 illustrates a schematic diagram of an optical system including a display assembly and an eye tracking assembly, according to an embodiment of the present disclosure
  • FIG. 6A is a schematic diagram of a near-eye display (“NED”), according to an embodiment of the disclosure.
  • FIG. 6B is a cross sectional view of a half of the NED shown in FIG. 6A, according to an embodiment of the disclosure.
  • FIG. 7A schematically illustrates a three-dimensional (“3D”) view of a liquid crystal polarization hologram (“LCPH”) element, according to an embodiment of the present disclosure
  • FIG. 7B schematically illustrates a sectional view of a portion of the LCPH element shown in FIG. 7A, showing in-plane orientations of optically anisotropic molecules in the LCPH element, according to an embodiment of the present disclosure
  • FIGs. 7C-7F schematically illustrate various views of a portion of the LCPH element shown in FIG. 7A, showing out-of-plane orientations of optically anisotropic molecules in the LCPH element, according to various embodiments of the present disclosure
  • FIG. 8A illustrates diffraction orders of a polarization volume hologram (“PVH”) element, according to an embodiment of the present disclosure
  • FIG. 8B illustrates diffraction orders of a reflective PVH element, according to an embodiment of the present disclosure
  • FIG. 9A illustrates a schematic diagram of a conventional waveguide display system
  • FIG. 9B illustrates a schematic diagram of a rainbow effect generated at an eyebox region of the system shown in FIG. 9A;
  • FIGs. 10A and 10B illustrate an optical path of an image light and an optical path of a real-world light that generates a first type of world side ghost (or rainbow) at an eye-box region of the system shown in FIG. 9A;
  • FIG. 10C illustrates an optical path of a real-world light that generates a second type of world side ghost (or rainbow-) at an eye-box region of the system shown in FIG. 9A;
  • FIG. 10D illustrates simulation results show ing ranges of angle of incidence (“AOI”) of real-world lights and an image light at a folding mirror included in the system shown in FIG. 9A;
  • AOI angle of incidence
  • FIG. 10E illustrates simulation results showing ranges of AOI of a real-world light and an image light at an out-coupling mirror included in the system shown in FIG. 9A;
  • FIG. 10F illustrates simulation results showing relationships between AOI and an efficiency of the first type of world side ghost and the second type of world side ghost within a field of view of the system shown in FIG. 9A;
  • FIG. 11 A illustrates a schematic diagram of a waveguide display system configured to reduce a world side ghost (or rainbow), according to an embodiment of the present disclosure
  • FIG. 1 IB illustrates a cross-sectional view of a portion of a waveguide along a first direction shown in FIG. 11 A, showing an optical path of an image light and an optical path of a real-w orld light in the system shown in FIG. 11 A, according to an embodiment of the present disclosure
  • FIG. 11C illustrates a cross-sectional view of a portion of the waveguide along a second direction shown in FIG. HA, showing an optical path of an image light and an optical path of a real-world light in the system shown in FIG. 11 A, according to an embodiment of the present disclosure
  • FIG. 1 ID illustrates a schematic diagram of a folding mirror embedded in the waveguide shown in FIG. 1 IB, according to an embodiment of the present disclosure
  • FIG. 1 IE illustrates a cross-sectional view of a portion of the waveguide along a first direction, showing an optical path of an image light and an optical path of a real-world light in the system shown in FIG. 11 A, according to an embodiment of the present disclosure
  • FIG. 1 IF illustrates a cross-sectional view of a portion of the waveguide along a second direction show n in FIG. 11 A, showing an optical path of an image light and an optical path of a real-world light in the system sho n in FIG. 11 A, according to an embodiment of the present disclosure
  • FIG. 12A illustrates a schematic diagram of a waveguide display system configured to reduce a w orld side ghost (or rainbow-), according to an embodiment of the present disclosure
  • FIG. 12B illustrates a cross-sectional view of a portion of a waveguide along a first direction shown in FIG. 12A, showing an optical path of an image light and an optical path of a real-world light in the system shown in FIG. 12A, according to an embodiment of the present disclosure
  • FIG. 12C illustrates a cross-sectional view of a portion of the waveguide along a second direction shown in FIG. 12A, showing an optical path of an image light and an optical path of a real-world light in the system shown in FIG. 12A, according to an embodiment of the present disclosure
  • FIG. 13 illustrates a schematic diagram of an artificial reality 7 device configured to reduce a world side ghost (or rainbow), according to an embodiment of the present disclosure
  • FIG. 14A illustrates a schematic diagram of an artificial reality device, according to an embodiment of the present disclosure.
  • FIG. 14B illustrates a schematic cross sectional view of half of the artificial reality device shown in FIG. 14A, according to an embodiment of the present disclosure.
  • the disclosed embodiments and the features of the disclosed embodiments may be combined.
  • the described embodiments are some but not all of the embodiments of the present disclosure.
  • persons of ordinary' skill in the art may derive other embodiments consistent with the present disclosure.
  • modifications, adaptations, substitutions, additions, or other variations may be made based on the disclosed embodiments.
  • Such variations of the disclosed embodiments are still within the scope of the present disclosure. Accordingly, the present disclosure is not limited to the disclosed embodiments. Instead, the scope of the present disclosure is defined by the appended claims.
  • the terms "couple.” “‘coupled,’” “coupling.” or the like may encompass an optical coupling, a mechanical coupling, an electrical coupling, an electromagnetic coupling, or any combination thereof.
  • An “optical coupling” between two optical elements refers to a configuration in which the two optical elements are arranged in an optical series, and a light output from one optical element may be directly or indirectly received by the other optical element.
  • An optical series refers to optical positioning of a plurality of optical elements in a light path, such that a light output from one optical element may be transmitted, reflected, diffracted, converted, modified, or otherwise processed or manipulated by one or more of other optical elements.
  • the sequence in which the plurality of optical elements are arranged may or may not affect an overall output of the plurality of optical elements.
  • a coupling may be a direct coupling or an indirect coupling (e.g., coupling through an intermediate element).
  • the phrase “at least one of A or B” may encompass all combinations of A and B, such as A only, B only, or A and B.
  • the phrase “at least one of A, B, or C” may encompass all combinations of A, B, and C, such as A only, B only, C only, A and B, A and C, B and C, or A and B and C.
  • the phrase “A and/or B” may be interpreted in a manner similar to that of the phrase “at least one of A or B.”
  • the phrase “A and/or B” may encompass all combinations of A and B, such as A only, B only, or A and B.
  • phrase “A, B, and/or C” has a meaning similar to that of the phrase “at least one of A, B. or C.”
  • the phrase “A, B, and/or C” may encompass all combinations of A, B, and C, such as A only, B only, C only, A and B, A and C, B and C, or A and B and C.
  • first element When a first element is described as “attached,” “provided,” “formed.” “affixed,” “mounted,” “secured,” “connected,” “bonded.” “recorded,” or “disposed.” to, on, at, or at least partially in a second element, the first element may be “attached,” “provided,” “formed,” “affixed,” “mounted,” “secured,” “connected,” “bonded,” “recorded,” or “disposed,” to, on, at, or at least partially in the second element using any suitable mechanical or non-mechanical manner, such as depositing, coating, etching, bonding, gluing, screwing, press-fitting, snap-fitting, clamping, etc.
  • the first element may be in direct contact with the second element, or there may be an intermediate element between the first element and the second element.
  • the first element may be disposed at any suitable side of the second element, such as left, right, front, back, top, or bottom.
  • first element When the first element is shown or described as being disposed or arranged “on” the second element, term “on” is merely used to indicate an example relative orientation between the first element and the second element. The description may be based on a reference coordinate system shown in a figure, or may be based on a current view or example configuration shown in a figure. For example, when a view shown in a figure is described, the first element may be described as being disposed “on” the second element. It is understood that the term “on” may not necessarily imply that the first element is over the second element in the vertical, gravitational direction.
  • the first element when the assembly of the first element and the second element is turned 180 degrees, the first element may be “under” the second element (or the second element may be “on” the first element).
  • the configuration is merely an illustrative example.
  • the first element may be disposed or arranged at any suitable orientation relative to the second element (e.g.. over or above the second element, below' or under the second element, left to the second element, right to the second element, behind the second element, in front of the second element, etc.).
  • the first element When the first element is described as being disposed “on” the second element, the first element may be directly or indirectly disposed on the second element.
  • the first element being directly disposed on the second element indicates that no additional element is disposed between the first element and the second element.
  • the first element being indirectly disposed on the second element indicates that one or more additional elements are disposed between the first element and the second element.
  • processor used herein may encompass any suitable processor, such as a central processing unit (“CPU”), a graphics processing unit (“GPU”), an application specific integrated circuit (“ASIC”), a programmable logic device (“PLD”), or any combination thereof. Other processors not listed above may also be used.
  • a processor may be implemented as software, hardware, firmware, or any combination thereof.
  • controller may encompass any suitable electrical circuit, software, or processor configured to generate a control signal for controlling a device, a circuit, an optical element, etc.
  • a “‘controller” may be implemented as software, hardware, firmware, or any combination thereof.
  • a controller may include a processor, or may be included as a part of a processor.
  • non-transitory computer-readable medium may encompass any suitable medium for storing, transferring, communicating, broadcasting, or transmitting data, signal, or information.
  • the non-transitory computer-readable medium may include a memory, a hard disk, a magnetic disk, an optical disk, a tape, etc.
  • the memory may include a read-only memory (“ROM”), a random-access memory' (“RAM”), a flash memory 7 , etc.
  • film may include rigid or flexible, self- supporting or free-standing film, layer, coating, or plate, which may be disposed on a supporting substrate or between substrates.
  • film may be interchangeable.
  • film plane refers to a plane in the film, layer, coating, or plate that is perpendicular to the thickness direction.
  • the film plane may be a plane in the volume of the film, layer, coating, or plate, or may be a surface plane of the film, layer, coating, or plate.
  • in-plane as in, e.g., “in-plane orientation,” “in-plane direction,” “in-plane pitch,” etc., means that the orientation, direction, or pitch is within the film plane.
  • out-of-plane as in, e.g., “out-of-plane direction,” “out-of-plane orientation,” or “out-of-plane pitch” etc., means that the orientation, direction, or pitch is not within a film plane (i.e., non-parallel with a film plane).
  • the direction, orientation, or pitch may be along a line that is perpendicular to a film plane, or that forms an acute or obtuse angle with respect to the film plane.
  • an “in- plane” direction or orientation may refer to a direction or orientation within a surface plane
  • an “out-of-plane” direction or orientation may refer to a thickness direction or orientation non-parallel with (e.g., perpendicular to) the surface plane.
  • orthogonal polarizations or the term “orthogonally” as in “orthogonally polarized” means that an inner product of two vectors representing the two polarizations is substantially zero.
  • two lights or beams with orthogonal polarizations may be two linearly polarized lights (or beams) with two orthogonal polarization directions (e.g., an x-axis direction and a y-axis direction in a Cartesian coordinate system) or two circularly polarized lights with opposite handednesses (e.g..
  • substantially or “primarily” used to modify an optical response action, such as transmit, reflect, diffract, block or the like that describes processing of a light means that a majority portion, including all, of a light is transmitted, reflected, diffracted, or blocked, etc.
  • the majority portion may be a predetermined percentage (greater than 50%) of the entire light, such as 100%, 95%, 90%, 85%, 80%, etc., which may be determined based on specific application needs.
  • FIGs. 1A-1C illustrate schematic diagrams of a conventional eye tracking system 100 that is implemented into an artificial reality device.
  • the artificial reality device may be in a form of eyeglasses or headset, which may include a frames 105 mounted to a user’s head.
  • the conventional eye tracking system 100 may include an infrared (“IR”) light source 107 that emits an infrared light to illuminate an eye 115 of a user wearing the artificial reality device, such as a pupil 1 16, an iris, a sclera, the entire eye 115, etc.
  • IR infrared
  • a camera 110 may be mounted on the frame of the eyeglasses or headset, arranged off-axis with respect to the eye 115 to receive the IR light reflected by the eye 115.
  • the camera 110 may generate a tracking signal based on the received IR light. Based on the tracking signal, the camera 1 10 may generate an image of the eye 115, which may be used to extract eye tracking information relating to the eye 1 15, such as gaze direction, pupil location, movement direction, psychological state, etc.
  • the camera 110 disposed around the frame may provide an out-of-field imaging of the eye 115. and the tracking signal generated by the camera 110 may provide insufficient information for determining eye tracking information as the eye 1 15 moves or rotates away from the camera 110. As shown in FIG. IB, when the eye 115 gazes substantially directly facing the camera 110, the tracking signal generated by the camera 110 may provide sufficient information for determining eye tracking information. In some cases, as shown in FIG. 1A, when the eye 115 gazes obliquely facing the camera 1 10, eye lashes may partially block the view of the camera 110. As shown in FIG.
  • the view of the camera 110 may be completely or significantly- blocked, and the view of the eye 115 (e.g., the entire pupil 116) may be completely or significantly lost.
  • the tracking signal generated by the camera 1 10 may provide insufficient information for determining eye tracking information, and the eyetracking accuracy may be significantly degraded.
  • the conventional eye tracking system 100 based on the out-of-field imaging of the eye 115 may not provide a high eye tracking accuracy, and the eye tracking range may be small.
  • FIGs. 2A-2C illustrate schematic diagrams of an eye tracking system 200 that may be implemented into an artificial reality device, according to an embodiment of the present disclosure.
  • an IR light source 207 may emit an infrared light to illuminate the eye 115 of a user wearing the artificial reality device.
  • An optical sensor (e.g., a camera) 210 may be mounted on a frame 205 of the eyeglasses or headset, and arranged off-axis with respect to the eye 115.
  • a waveguide (or light guide) based imaging assembly 220 may bring the camera 210 virtually in front of the eye 115, forming a virtual, direct view camera 215 in front of the eye 115.
  • the virtual, direct view camera 215 may provide an in-field imaging of the eye 115.
  • ‘‘Field” in the phrases “out-of- field imaging” and “in-field imaging” refers to a field of view of an eye of a user when using a system or device including the elements that provide the out-of-field (or in-field) imaging of the eye 115.
  • the virtual, direct view camera 215 may constantly receive the IR light reflected by the eye 115 (e.g., the pupil 116), and the tracking signal generated by the virtual camera 215 may constantly provide sufficient information for determining eye tracking information.
  • the disclosed eye tracking system 200 provides a larger tracking range when the eye 115 moves or rotates in the horizontal and/or vertical directions. Thus, the disclosed eye tracking system 200 enhances the accuracy of the eye tracking and improves the user experience.
  • FIG. 3A illustrates an x-z sectional view (e.g., a top view) of an object tracking system (e.g., eye tracking system) 300, according to an embodiment of the present disclosure.
  • the object tracking system 300 may also be referred to as an eye tracking (and face tracking) assembly 300.
  • the eye tracking system 300 may be a detailed embodiment of the eye tracking system 200 shown in FIGs. 2A-2C.
  • the eye tracking system 300 may be a part of a system (e.g., an HUD, an HMD, a smart phone, a laptop, or a television, etc.) for VR, AR. and/or MR applications.
  • the eye tracking system 300 may track a position, a movement, and/or a viewing direction of the eye pupil 116 when the eye 115 moves or rotates in the horizontal (e.g., x- axis direction and/or y-axis direction) and/or vertical directions (e.g., z-axis direction), with an enhanced eye tracking accuracy.
  • the eye tracking system 300 maymeasure the eye position and/or eye movement up to six degrees of freedom (i.e., 3D position, roll, pitch, and yaw) for each eye 115.
  • the eye tracking system 300 may measure a pupil size.
  • the eye tracking system 300 may include the light source 207 configured to emit a tight 302 to illuminate one or both eyes 115 (and in some embodiments the face) of a user of the eye tracking system 300.
  • the eye tracking system 300 may also include a waveguide (or light guide) imaging assembly 320 configured to generate an image of the eye 115 based on the light reflected by the eye 115.
  • FIG. 3 A shows one light source 207 and one eye 115 for illustrative purposes. It is understood that any suitable number of light sources 207 may be included, and components for tracking the eye 115 may be replicated for tracking the other eye of the user, which are not shown in FIG. 3A.
  • the position of the light source 207 shown in FIG. 3A is for illustrative purposes, and the light source 207 may be arranged off-axis or on-axis with respect to the eye 115.
  • the light source 207 may be positioned out of a line of sight of the user (e g., above and in front of the eye 115). In some embodiments, the light source 207 may emit the light 302 in the IR spectrum. For example, the spectrum of the light 302 emitted by the light source 207 may be within, overlap, or encompass at least a portion of the IR spectrum. In some embodiments, the light source 207 may emit the tight 302 in the near infrared (“NIR”) spectrum, or any other spectrum such that the light 302 is not visible by the eye 115. IR lights are not visible to the human eyes and thus, do not distract the user during operations.
  • NIR near infrared
  • the light 302 emitted by the light source 207 may be reflected as a light 304 by the pupil 1 16 of the eye 115, the entire eye 1 15, an area surrounding the pupil 116 or the eye 115, including the eye lid and/or the facial skins or other tissues around or inside the eye 115.
  • the light reflected by such regions in or around the pupil 116 or the eye 115 is simply referred to as a light reflected by the eye 115.
  • the light source 207 may be configured to provide a structured light to illuminate the eye 115, or a structured illumination (or structured tight pattern) to the eye 115.
  • the structured illumination may increase the tracking accuracy of the eye 115.
  • the structured illumination may also enable the depth reconstruction of a tracked object, such as the face.
  • the structured light may include at least one of an intensitybased structured light or a polarization-based structured light.
  • the waveguide imaging assembly 320 may include a waveguide (or light guide) 310, an in-coupling element 335, an out-coupling element 345, and the optical sensor 210.
  • the optical sensor 210 may be disposed obliquely with respect to the line of sight of the eye 115. For example, the facing direction of the optical sensor 210 may not be parallel with the normal of the surface of the waveguide 310.
  • the waveguide 310 may include a first surface or side 310-1 facing the eye 115, and a second surface or side 310-2 opposite to the first surface 310-1.
  • Each of the in-coupling element 335 and the out-coupling element 345 may be disposed at the first surface 310-1 or the second surface 310-2 of the waveguide 310.
  • FIG. 3A shows that the optical sensor (e.g., a camera) 210 and the eye 115 are disposed at different sides of the waveguide 310.
  • the positions of the optical sensor (e.g., a camera) 210 and the eye 115 shown in FIG. 3 A are for illustrative purposes.
  • the optical sensor (e.g., a camera) 210 and the eye 115 may be disposed at different locations on the same side of the waveguide 310.
  • the in-coupling element 335 may be disposed at the first surface 310-1 of the waveguide 310, and the out-coupling element 345 may be disposed at the second surface 310-2 of the waveguide 310. In some embodiments, the in-coupling element 335 may be disposed at the second surface 310-2 of the waveguide 310, and the out-coupling element 345 may be disposed at the first surface 310-1 of the waveguide 310. In some embodiments, both of the in-coupling element 335 and the out- coupling element 345 may be disposed at the first surface 310-1 or at the second surface 310- 2 of the waveguide 310.
  • the in-coupling element 335 or the out- coupling element 345 may be integrally formed as a part of the waveguide 310 at the corresponding surface(s). In some embodiments, the in-coupling element 335 or the out- coupling element 345 may be separately formed, and may be disposed at (e.g., affixed to) the corresponding surface(s).
  • the in-coupling element 335 and the out-coupling element 345 may operate in a predetermined wavelength range or spectrum that includes at least a portion of the IR spectrum, and may not operate in the visible spectrum. That is. the in-coupling element 335 and the out-coupling element 345 may deflect an IR light when the IR light satisfies a predetermined condition, while functioning as a transparent plate for visible lights without any deflection.
  • the in-coupling element 335 may be disposed at a first portion (e.g., an input portion) of the waveguide 310, and the out-coupling element 345 may be disposed at a second, different portion (e.g., an output portion) of the waveguide 310.
  • the first portion (e.g., input portion) of the waveguide 310 may be closer to the eye 115 than the second, different portion (e.g., output portion) of the waveguide 310.
  • the in-coupling element 335 may be disposed facing the eye 115. e.g., substantially directly facing the eye 115.
  • the incoupling element 335 may be positioned in a line of sight of the user.
  • the in-coupling element 335 may be configured to couple, via deflection, the light 304 reflected by the eye 115 into the waveguide 310 as an in-coupled light 306 propagating inside the waveguide 310 toward the out-coupling element 345 via total internal reflection ( ‘TIR”).
  • TIR total internal reflection
  • the out-coupling element 345 may be disposed obliquely with respect to the line of sight of the eye 115.
  • the out-coupling element 345 may be disposed at a location that is off-axis with respect to the eye 115.
  • the out-coupling element 345 may be positioned out of a line of sight of the eye 115.
  • the out-coupling element 345 may be disposed facing the optical sensor 210, and configured to couple, via deflection, the incoupled light 306 out of the waveguide 310 as one or more output lights 308 propagating toward the optical sensor 210.
  • FIG. 3A merely shows the light propagation path of a central ray of the light 304 inside the waveguide 310.
  • each of the in-coupling element 335 and the out-coupling element 345 may include one or more diffraction gratings, one or more cascaded reflectors, one or more prismatic surface elements, and/or an array of holographic reflectors, or any combination thereof.
  • each of the in-coupling element 335 and the out- coupling element 345 may include a diffraction grating, such as a surface relief grating, a volume hologram, a polarization selective grating, a metasurface grating, or any combination thereof.
  • polarization selective gratings may include a holographic polymer- dispersed liquid crystal (“H-PDLC”) grating, a surface relief grating provided (e.g., filled) with LCs, a Pancharatnam-Berry phase (“PBP”) grating, a polarization volume hologram (“PVH”) grating, etc.
  • H-PDLC holographic polymer- dispersed liquid crystal
  • PBP Pancharatnam-Berry phase
  • PVH polarization volume hologram
  • the diffraction grating may be a reflective grating configured to backwardly diffract an IR light when the IR light satisfies a predetermined condition.
  • the diffraction grating may be a transmissive grating configured to forwardly diffract an IR light when the IR light satisfies a predetermined condition.
  • the diffraction grating may be polarization selective, or polarization non- selective.
  • a period of the diffraction grating included in the incoupling element 335 may be configured to enable TIR of the reflected light 304 within the w aveguide 310.
  • a period of the diffraction grating included in the out- coupling element 345 may be configured to couple the in-coupled light 306 propagating inside the w aveguide 310 through TIR out of the w aveguide 310 via diffraction.
  • the diffraction grating in the in-coupling element 335 and/or the out-coupling element 345 may be configured with a substantially high diffraction efficiency for the IR light, such that the waveguide imaging assembly 320 may have a high overall efficiency.
  • the waveguide 310 may include one or more materials configured to facilitate the TIR of the in-coupled light 306.
  • the waveguide 310 may include, for example, a plastic, a glass, and/or polymers.
  • the waveguide 310 may have a relatively small form factor.
  • the optical sensor 210 may be disposed facing the output region of the waveguide 310, and facing the out-coupling element 345.
  • the optical sensor 210 may be positioned out of a line of sight of the user, and may be disposed at locations that are off-axis with respect to the eye 115.
  • the optical sensor 210 may be configured to generate images based on lights having a wavelength within a predetermined wavelength range or spectrum that includes at least a portion of the IR spectrum. In some embodiments, the optical sensor 210 may be configured to generate images based on IR lights but not visible lights.
  • the optical sensor 210 may include a camera, or a photodiode, etc., such as one or more of a charge-coupled device (‘‘CCD’’) camera, a complementary metal-oxide-semiconductor (‘'CMOS”) sensor, an N-type metal-oxide-semiconductor (“NMOS”) sensor, a pixelated polarized camera, or any other optical sensors.
  • a camera or a photodiode, etc.
  • a camera such as one or more of a charge-coupled device (‘‘CCD’’) camera, a complementary metal-oxide-semiconductor (‘'CMOS”) sensor, an N-type metal-oxide-semiconductor (“NMOS”) sensor, a pixelated polarized camera, or any other optical sensors.
  • a camera or a photodiode, etc.
  • a photodiode such as one or more of a charge-coupled device (‘‘CCD’’)
  • the optical sensor 210 may be configured to receive the one or more output lights 308.
  • the output light 308 may also be referred to as a signal light for determining the eye tracking information of the eye 115.
  • FIG. 3A shows that the optical sensor 210 is disposed at a side of the waveguide 310 opposite to the side where the eye 115 is located. In some embodiments, the optical sensor 210 and the eye 115 may be disposed at the same side of the waveguide 310.
  • FIG. 3A shows that the optical sensor 210 receives a single signal light 308. In some embodiments, the optical sensor 210 may receive a plurality of signal lights 308.
  • the eye tracking system 300 may generate a tracking signal or data based on the received signal light 308 for eye tracking (referred to as eye tracking signals, information, or data).
  • the eye tracking system 300 may analyze or process the signal light 308 to generate the eye tracking information.
  • the optical sensor 210 may include a processor configured to process the received signal light 308 to generate an image of the eye 115.
  • the optical sensor 210 may further analyze the generated image of the eye 115 to obtain information that may be used for eye tracking and other purposes, such as for determining what information to present to the user, for configuring the layout of the presentation of the information, for addressing vergence-accommodation conflict, etc.
  • the optical sensor 210 may also include a non-transitory computer- readable storage medium (e.g., a computer-readable memory) configured to store data, such as the generated images.
  • a non-transitory computer- readable storage medium e.g., a computer-readable memory
  • the non-transitoiy computer-readable storage medium may store codes or instructions that may be executable by the processor to perform various steps of any methods disclosed herein.
  • the processor and the non-transitory computer-readable medium may be provided separately from the optical sensor 210.
  • the eye tracking system 300 may include a controller 325 communicatively connected with the optical sensor 210 and configured to receive data from the optical sensor 210.
  • the controller 325 may include a processor or processing unit 321 and a storage device 323.
  • the processor 321 may be any suitable processor, such as a central processing unit (“CPU”), a graphic processing unit (“GPU”), etc.
  • the storage device 323 may be a non-transitory computer- readable medium, such as a memory, a hard disk, etc.
  • the storage device 323 may be configured to store data or information, including computer-executable program instructions or codes, which may be executed by the processor 321 to perform various controls or functions of the methods or processes disclosed herein.
  • the controller 325 maybe configured to analyze the data (e.g., signals) received from the optical sensor 210 to obtain information for eye tracking or other purposes.
  • the optical sensor 210 may be disposed facing the output region of the waveguide 310, and disposed obliquely or off-axis with respect to the eye 115 to provide an out-of-field imaging of the eye 115.
  • the waveguide 310 coupled with the in-coupling element 335 and the out-coupling element 345 may guide the light 304 reflected from the eye 115 to the optical sensor 210, thereby virtually moving the optical sensor 210 from facing the output region of the waveguide 310 to a spatial location right in front of and facing the input region of the waveguide 310 where the eye 115 is located. As shown in FIG.
  • a virtual, direct view optical sensor (e.g., virtual camera) 215 is created right in front of the input region of the waveguide 310, as if the actual optical sensor 210 is disposed right in front of the input region facing the eye 115. Therefore, an infield imaging of the eye 115 is provided.
  • a virtual, direct view optical sensor e.g., virtual camera
  • the virtual camera 215 may constantly receive the light 304 reflected by the eye 115, e g., the pupil 116, the iris, the sclera, the entire eye, the area surrounding the eye 115, including the eye lid and/or the facial skins or other tissues around or inside the eye 115.
  • the tracking signal generated by the virtual camera 215 may constantly provide sufficient information for determining eye tracking information. Accordingly, the eye tracking range may be expanded, and the eye tracking accuracy may be increased.
  • the optical sensor 210 may be configured with a large depth of field, e.g., greater than 2 centimeters (e.g., along a z-axis direction). Thus, the optical sensor 210 may provide a tracking signal that includes the depth information of the eye 115 (and/or the face).
  • the in-coupling element 335 configured with a small size may still receive the diffusive reflection from the eye 115 when the eye 115 moves or rotates in the horizontal (e.g., x-axis direction and/or y-axis direction) and/or vertical directions (e.g., z-axis direction).
  • the width of the in-coupling element 335 may be configured to be at the sub-millimeter level, such as 200-300 micrometers, 300-400 micrometers, 400-500 micrometers, or 500-600 micrometers, etc.
  • the length of the in-coupling element 335 (e.g., along the length direction of the waveguide 310, e.g., the y-axis direction) may be configured to be comparable with (e.g., the same as or slightly smaller than) the size of the length of the waveguide 310.
  • the in-coupling element 335 having the sub-millimeter width may be substantially invisible to the eye 115.
  • the width of the in-coupling element 335 may be at the sub-millimeter level, such that the in-coupled light 306 may propagate inside the waveguide 310 via TIR toward the out-coupling element 345, without interacting with the in-coupling element 335 again and being coupled out of the waveguide 310 by the in-coupling element 335.
  • the optical efficiency at the input side of the waveguide 310 (or the input efficiency of the incoupling element 335) is improved.
  • both of the in-coupling element 335 and the out-coupling element 345 may be configured with a substantially high coupling efficiency for the IR light, such that the waveguide imaging assembly 320 may have a high overall efficiency.
  • a visible polychromatic light 334 coming from a real -world environment may be incident onto the waveguide 310.
  • the visible polychromatic light 334 may be diffracted, refracted, and/or reflected by a diffractive element having an operation wavelength range in the visible spectrum, causing a multicolored glare in a see-through view, especially when a user wearing the NED.
  • HUD, or HMD looks at a bright light source from certain angles.
  • Such a see-through artifact is referred to as a rainbow effect, which may degrade the image quality of the see-through view.
  • the in-coupling element 335 and the out-coupling element 345 may not diffract, refract, and/or reflect the visible polychromatic light 334.
  • the waveguide 310 coupled with the in-coupling element 335 and the out-coupling element 345 may substantially transmit the visible polychromatic light 334 without degrading the image quality of the see-through view.
  • both the in-coupling element 335 and the out-coupling element 345 may be transmissive gratings.
  • the in-coupling element 335 may be configured to couple, via forward diffraction, the light 304 reflected by the eye 115 into the waveguide 310 as the in-coupled light 306 propagating inside the waveguide 310 toward the out-coupling element 345 via TIR.
  • the out-coupling element 345 may be configured to couple, via forward diffraction, the in-coupled light 306 out of the waveguide 310 as one or more output lights 308 propagating toward the optical sensor 210.
  • both of the in-coupling element 335 and the out-coupling element 345 may be reflective gratings.
  • one of the in-coupling element 335 and the out-coupling element 345 may be a reflective grating, and the other one of the in-coupling element 335 and the out-coupling element 345 may be a transmissive grating.
  • FIG. 3B illustrates an x-z sectional view (e.g., a top view) of an object tracking system (e.g., eye tracking system) 350, according to an embodiment of the present disclosure.
  • the object tracking system 350 may also be referred to as an eye tracking (and face tracking) assembly 350.
  • the eye tracking system 350 may be a detailed embodiment of the eye tracking system 200 shown in FIGs. 2A-2C.
  • the eye tracking system 350 may include elements, structures, and/or functions that are the same as or similar to those included in the eye tracking system 300 shown in FIG. 3A. Detailed descriptions of the same or similar elements, structures, and/or functions may refer to the above descriptions rendered in connection with FIGs. 2A-2C and FIG. 3A.
  • the eye tracking system 350 may include the light source 207, and a w aveguide (or light guide) imaging assembly 370.
  • the w aveguide imaging assembly 370 may include the waveguide (or light guide) 310, an in-coupling element 355 and an out-coupling element 365, and the optical sensor 210.
  • the in-coupling element 355 may be disposed at the second surface 310-2 of the waveguide 310.
  • the out-coupling element 365 may be disposed at the first surface 310-1 of the waveguide 310. Both of the incoupling element 355 and the out-coupling element 365 may be reflective gratings.
  • the incoupling element 355 may be configured to couple, via backward diffraction, the light 304 reflected by the eye 115 into the waveguide 310 as an in-coupled light 376 propagating inside the w aveguide 310 toward the out-coupling element 365 via TIR.
  • the out-coupling element 365 may be configured to couple, via backward diffraction, the in-coupled light 376 out of the waveguide 310 as one or more output lights 378 propagating toward the optical sensor 210.
  • FIG. 3B merely shows the light propagation path of a central ray of the light 304 inside the waveguide 310.
  • At least one of the in-coupling element 335, the out- coupling element 345, the in-coupling element 355, or the out-coupling element 365 may include a liquid crystal polarization hologram (“LCPH”) element.
  • LCPHs Liquid crystal polarization holograms
  • LCPHs have features such as small thickness (about 1 pm), light weight, compactness, large aperture, high efficiency, simple fabrication, etc. Thus. LCPHs have gained increasing interests in optical device and system applications. Detailed descriptions of the LCPH elements may refer to the descriptions rendered in connection with FIGs. 7A-8B.
  • 3A or the object tracking system 350 shown in FIG. 3B are used as an example structure in illustrating and explaining the operation principles of using any disclosed waveguide imaging system to provide an in-field imaging of an object, and to enhance the tracking range and tracking accuracy of the object.
  • the design principles may be applicable to any suitable object tracking systems other than the disclosed object tracking system 300 shown in FIG. 3A or the object tracking system 350 shown in FIG. 3B.
  • the disclosed object tracking system may have numerous applications in a large variety of fields, e.g., NEDs, HUDs, HMDs, smart phones, laptops, televisions, vehicles, etc.
  • the disclosed optical systems may be implemented in various systems for augmented reality (“AR”’), virtual reality (“VR”), and/or mixed reality (“MR”) applications, to determine what content to provide to the user, to solve the vergence-accommodation conflict, to enable pupil steered AR, VR, and/or MR display systems (including, but not limited to, holographic near eye displays, retinal projection eyewear, and wedged waveguide displays), etc.
  • the disclosed object tracking systems may be implemented in sensing modules to extend the detecting range of the sensors, increase detecting resolution or accuracy of the sensors, and/or reduce the signal processing time.
  • FIG. 4A illustrates an x-z sectional view of an optical system 400, according to an embodiment of the present disclosure.
  • the optical system 400 may be a part of a system (e.g.. an NED, an HUD, an HMD. a smart phone, a laptop, or a television, etc.) for VR, AR, and/or MR applications.
  • the optical system 400 may include an object tracking assembly 420 and a waveguide (or light guide) display assembly 450.
  • the object tracking assembly 420 may also be referred to as an eye tracking (and face tracking) assembly 420.
  • the eye tracking assembly 420 may be an embodiment of the eye tracking systems disclosed herein, such as the eye tracking system 200 shown in FIGs.
  • FIG. 3A the eye tracking system 300 shown in FIG. 3A, or the eye tracking sy stem 350 shown in FIG. 3B.
  • FIG. 3B the eye tracking system 300 shown in FIG. 3A
  • FIG. 3B the eye tracking sy stem 350
  • Detailed descriptions of the same or similar elements, structures, and/or functions may refer to the above descriptions rendered in connection with FIGs. 2A-3B.
  • the eye tracking assembly 420 may be similar to the eye tracking system 300 shown in FIG. 3A.
  • the eye tracking assembly 420 may include the light source 207, and the waveguide imaging assemblyincluding the waveguide (or light guide) 310 coupled with the in-coupling element 335 and the out-coupling element 345, and the optical sensor 210.
  • the light source 207 may be configured to emit the IR light 302 toward the eye 115.
  • the waveguide 310 coupled with the in-coupling element 335 and the out-coupling element 345 may be configured to guide the IR light 304 reflected from the eye 115 toward the optical sensor 210, thereby providing the virtual, direct view camera 215 in front of the eye 215.
  • the optical sensor 210 may generate one or more images of the eye 115, which include the eye (and face) tracking information.
  • an IR light is denoted by a dashed line with an arrow.
  • the waveguide display assembly 450 and the eye tracking assembly 420 share the waveguide 310 and the controller 325.
  • the w aveguide display assembly 450 and the eye tracking assembly 420 may have individual or separate waveguides and/or individual or separate controllers.
  • the waveguide display assembly 450 may include the waveguide 310, the in-coupling element 435 and the out-coupling element 445
  • the eye tracking assembly 420 may include the waveguide 310, the in-coupling element 335 and the out-coupling element 345.
  • the in-coupling element 435 may be configured to couple a visible image light into the waveguide 310, and the out-coupling element 445 may be configured to couple the visible image light out of the waveguide 310 toward the eye 115 to provide a virtual image for the user to view.
  • the in-coupling element 335 may be configured to couple a non-visible infrared light reflected from the eye 115 into the waveguide 310, and the out-coupling element 345 may be configured to couple the infrared light out of the waveguide 310 toward the optical sensor 210 for eye tracking purposes.
  • the light source assembly 405 may generate and output an image light (e.g., a visible light representing a virtual image) 430 propagating tow ard the in-coupling element 435.
  • a visible light is denoted by a solid line with an arrow;
  • the waveguide 310 coupled with the in-coupling element 435 and the out-coupling element 445 may expand and direct the image light 430 to the eye 1 15 positioned in an eye-box 460 of the waveguide display assembly 450.
  • the eye-box 460 is a region in space where an eye pupil 116 of the eye 115 of a user can perceive the full extent of the virtual image delivered by the waveguide 310 from the light source assembly 405.
  • An exit pupil 465 may be a location where the eye 115 is positioned in the eye-box 460.
  • the light source assembly 405 may include a light source 429 and a light conditioning system 425.
  • the light source 429 may be a light source configured to generate a coherent or partially coherent visible light.
  • the light source 429 may be a display panel.
  • the light conditioning system 425 may include one or more optical components configured to condition the light from the light source 429.
  • the controller 325 may control the light conditioning system 425 to condition the light from the light source 429, which may include, e.g., transmitting, attenuating, expanding, collimating, and/or adjusting orientation of the light.
  • the in-coupling element 435 may be disposed at the second portion of the waveguide 310. That is, both of the in-coupling element 435 for the visible image light and the out-coupling element 345 for the IR light may be disposed at the second portion of the waveguide 310.
  • the in-coupling element 435 for the visible image light 430 and the out- coupling element 345 for the IR light may be disposed at the same surface or different surfaces of the waveguide 310.
  • the out-coupling element 445 may be disposed at the first portion of the waveguide 310. That is, both the out-coupling element 445 for the visible image light and the in-coupling element 335 for the IR light may be disposed at the first portion of the waveguide 310.
  • the out-coupling element 445 for the visible image light and the in-coupling element 335 for the IR light may be disposed at the same surface or different surfaces of the waveguide 310.
  • each of the in-coupling element 435 and the out-coupling element 445 may have a designed operating wavelength band that includes at least a portion of the visible wavelength band.
  • the designed operating wavelength band of each of the in-coupling element 435 and the out-coupling element 445 may not include the IR wavelength band.
  • each of the in-coupling element 435 and the out-coupling element 445 may be configured to deflect a visible light, and transmit an IR light without a deflection or with negligible deflection.
  • the image light 430 output from the light source assembly 405 may propagate toward the in-coupling element 435 disposed at the second portion of the waveguide 310.
  • the in-coupling element 435 may couple the image light 430 into the waveguide 310 as an in-coupled image light 432, which may propagate inside the waveguide 310 through TIR along the pupil expansion direction (e.g., an x-axis direction) toward the out-coupling element 445 located at the first portion of the waveguide 310.
  • the out-coupling element 445 may couple the in-coupled image light 432, which is incident onto different portions of the out-coupling element 445, out of the waveguide 310 as a plurality of output image lights 434 propagating toward the eye-box 460.
  • Each output image light 434 may include the same image content as the input image light 430 and, thus, the waveguide display assembly 450 may provide pupil replication (or pupil expansion) at a side of the waveguide 310 where the eye 115 is located.
  • the waveguide 310 coupled with the in-coupling element 435 and the out-coupling element 445 may also function as an image combiner (e.g., AR or MR combiner).
  • the waveguide 310 may combine the image light 432 representing a virtual image and the light 334 from the real world environment (or a real world light 334), such that the virtual image may be superimposed with real-world image.
  • the in-coupling element 335 and the out-coupling element 345 are configured for the IR light rather than the visible light, the in-coupling element 335 and the out-coupling element 345 may not alter the propagation path of the visible light.
  • the in-coupling element 335 for the IR light may substantially transmit both of the output image light 434 coupled out from the waveguide 310 and the real world light 334, without deflection or with negligible deflection.
  • the image light 434 and the real world light 334 may propagate through the in-coupling element 335 toward the eye 115.
  • FIG. 4A shows a ID pupil replication in the x-axis direction.
  • the width of the out-coupling element 445 for the visible image light may be configured to be at least comparable with (e.g., the same as or slightly larger than) the size of the eye pupil 116.
  • the size of the eye pupil 116 of an average adult user may vary in a range of 4-8 millimeters ("mm") in diameter when dilated (e.g.. when in dark), or vary in a range of 2-4 mm in diameter when constricted (e.g., when in bright light).
  • the size of the eye pupil 116 may vary in the range of 2-8 mm depending on the light intensity- (or brightness) of the image light.
  • a redirecting element 440 may 7 be coupled to the waveguide 310, and configured to redirect the in-coupled image light 432 to the out-coupling element 445.
  • the w aveguide display assembly is referred to as 470
  • the image light out- coupled by the out-coupling element 445 is referred to as 484.
  • the out-coupling element 445 may couple the in-coupled image light 432 out of the waveguide 310.
  • the redirecting element 440 may be separately formed and disposed at (e g., affixed to) the corresponding surface of the waveguide 310.
  • the redirecting element 440 and the out-coupling element 445 may have a similar structure.
  • the width of the redirecting element 440 for the visible image light may be configured to be greater than the width of the in-coupling element 335 for the IR light.
  • FIG. 4C illustrates an x-z sectional view of an optical system 490, according to an embodiment of the present disclosure.
  • the optical system 490 may be a part of a system (e.g., an NED, an HUD, an HMD, a smart phone, a laptop, or a television, etc.) for VR, AR, and/or MR applications.
  • the optical system 490 may include the same or similar elements, structures, and/or functions that are the same as or similar to those included in the optical system 400 shown in FIG. 4A, or the optical system 480 shown in FIG. 4B. Detailed descriptions of the same or similar elements, structures, and/or functions may refer to the above descriptions rendered in connection with FIGs. 4A and 4B.
  • the optical system 490 may include the eye tracking assembly 420 and a waveguide (or light guide) display assembly 495.
  • the waveguide display assembly 495 and the eye tracking assembly 420 may have individual waveguides, e.g., waveguides 410 and 310.
  • the waveguide display assembly 495 may be similar to the waveguide display assembly 450 shown in FIG. 4 A.
  • the waveguide display assembly 495 may include the light source assembly 405. and the waveguide 410 coupled with the in-coupling element 435 and the out-coupling element 445.
  • the waveguide 410 may be stacked with the waveguide 310 included in the eye tracking assembly 420.
  • the waveguides 310 and 410 may be separated by an air gap.
  • the air gap between the neighboring waveguides 310 and 410 may be at least partially filled with a material (e.g., a liquid glue) having a refractive index lower than that of the waveguides 310 and 410.
  • the out-coupling element 445 and the in-coupling element 435 may be disposed at a first portion and a second portion of the waveguide 410, respectively.
  • the in-coupling element 335 may be stacked with the out-coupling element 445.
  • the out-coupling element 445 when the out-coupling element 445 is disposed at the first surface 410-1 of the waveguide 410. the in-coupling element 335 may directly contact the second surface 410-2 of the waveguide 410.
  • each of the in-coupling element 335, the out-coupling element 345, the in-coupling element 435, and the out-coupling element 445 may be disposed at either the first surface or the second surface of the respective waveguide 310, 410. in some embodiments, at least one of the in-coupling element 335, the out-coupling element 345. the in-coupling element 435. the out-coupling element 445 may be disposed between the two waveguides 310, 410, or in some embodiments, none of the in-coupling element 335, the out-coupling element 345, the in-coupling element 435, the out-coupling element 445 may be disposed betw een the two waveguides 310, 410. Any number of combinations of the in-coupling element 335, the out-coupling element 345, the in-coupling element 435, the out-coupling element 445 may be disposed between the two waveguides 310, 410.
  • FIG. 5 illustrates an x-z sectional view of an optical system 500, according to an embodiment of the present disclosure.
  • the optical system 500 may be a part of a system (e.g.. an NED, an HUD, an HMD. a smart phone, a laptop, or a television, etc.) for VR, AR, and/or MR applications.
  • the optical system 500 may include the same or similar elements, structures, and/or functions that are the same as or similar to those included in the optical system 400 shown in FIG. 4A, the optical system 480 shown in FIG. 4B, or the optical system 490 shown in FIG. 4C.
  • Detailed descriptions of the same or similar elements, structures, and/or functions may refer to the above descriptions rendered in connection with FIGs. 4A-4C.
  • the optical system 500 may include a display system 575, a viewing optical system 580, and the eye tracking assembly 420, and the controller 325 (not shown).
  • the display system 575 may display virtual images to the user.
  • the display system 575 may include a single electronic display or multiple electronic displays 576 (e.g., a display for each eye 115 of the user).
  • FIG. 5 shows that the display system 575 includes two electronic displays 576 for the left and right eyes 115 of the user of the optical system 500.
  • the display system 575 and the viewing optical system 580 together may guide an image light (forming the virtual images) to the respective exit pupil 465 in the respective eye-box region 460.
  • the viewing optical system 580 may include two lenses or lens assemblies 581 for the left and right eyes 115.
  • the lens or lens assembly 581 may be configured to address the accommodation-vergence conflict in the optical system 500.
  • the electronic displays 576 may display a virtual image. Based on the eye tracking information provided by the eye tracking assembly 420, the controller 325 may determine a virtual object 578 within the virtual image at which the eyes 115 are currently looking. The controller 325 may determine a vergence depth (dv) of the gaze of the user based on the gaze point or an estimated intersection of gaze lines 579 determined by the eye tracking assembly 420. As shown in FIG. 5, the gaze lines 579 may converge or intersect at the distance dv, where the virtual object 578 is located.
  • dv vergence depth
  • the controller 325 may control the lens or lens assembly 581 to adjust the optical power to provide an accommodation that matches the vergence depth (dv) associated with the virtual object 578 at which the eyes 115 are currently looking, thereby reducing the accommodationvergence conflict in the optical system 500.
  • the controller 325 may control the lens or lens assembly 581 to operate in a desirable operation state to provide an optical power corresponding to a focal plane (or an image plane) that matches the vergence depth (dv).
  • optical system 400 shown in FIG. 4A the configuration of the optical system 400 shown in FIG. 4A, the optical system 480 shown in FIG. 4B. the optical system 490 shown in FIG. 4C, or the optical system 500 shown in FIG. 5 are used as an example structure that includes both of a display assembly and a disclosed object tracking assembly.
  • Other display assemblies may also be used in combination with a disclosed object tracking assembly.
  • FIG. 6A illustrates a schematic diagram of a near-eye display (“NED"’) 600 according to an embodiment of the disclosure.
  • FIG. 6B is a cross-sectional view of half of the NED 600 show n in FIG. 6A according to an embodiment of the disclosure.
  • FIG. 6B shows the cross-sectional view associated with a left-eye display system 610L.
  • the NED 600 may include a controller (e.g., the controller 325), which is not shown in FIG. 6A or 6B.
  • the NED 600 may include a frame 605 configured to mount to a user’s head.
  • the frame 605 is merely an example structure to which various components of the NED 600 may be mounted.
  • the NED 600 may include right-eye and left-eye display systems 610R and 610L mounted to the frame 605.
  • the NED 600 may function as a VR device, an AR device, an MR device, or any combination thereof.
  • the right-eye and left-eye display systems 610R and 610L may be entirely or partially transparent from the perspective of the user, which may provide the user with a view of a surrounding real-world environment.
  • the NED 600 when the NED 600 functions as a VR device, the righteye and left-eye display systems 610R and 610L may be opaque, such that the user may be immersed in the VR imagery based on computer-generated images.
  • the right-eye and left-eye display systems 610R and 610L may include image display components configured to project computer-generated virtual images into left and right display windows 615L and 615R in a field of view ( ‘FOV”).
  • the right-eye and left-eye display systems 61 OR and 610L may be any suitable display systems, such as the waveguide display assembly 450 shown in FIG. 4A, the waveguide display assembly 470 shown in FIG. 4B. the waveguide display assembly 495 shown in FIG. 4C, or the display system 575 shown in FIG. 5.
  • FIG. 6A shows that the right-eye and left-eye display systems 61 OR and 10L may include a light source assembly (e.g., a projector) 635 coupled to the frame 605.
  • the projector 635 may generate an image light representing a virtual image.
  • the NED 600 may also include a lens system 685 and an object tracking system 670 (e.g., eye tracking system and/or face tracking system).
  • the lens system 685 may be disposed between the object tracking system 670 and the left-eye display system 610L.
  • the lens system 685 may be configured to guide the image light output from the left-eye display system 610L to an exit pupil 465.
  • the object tracking system 670 may be any embodiment of the object tracking system disclosed herein, such as the object tracking system 200 shown in FIGs. 2A-2C, the object tracking system 300 shown in FIG. 3A, or the object tracking system 350 shown in FIG. 3B. With the object tracking system 670.
  • the NED 600 may provide enhanced tracking accuracy and tracking range for eye tracking and/or face tracking.
  • Information obtained during eye tracking and/or face tracking may be used for determining the type of information to be presented to the user of the NED 600 and/or the arrangement of the content displayed on a display screen of the NED 600, addressing the vergence-accommodation conflict, and enhancing display quality and performance of the NED 600. Accordingly, the user experience of the NED 600 may be enhanced.
  • FIG. 6B show s that the object tracking system 670 may be similar to the object tracking system 300 shown in FIG. 3A.
  • the object tracking system 670 may include the light source 207, the waveguide 310 coupled with the in-coupling element 335 and the out-coupling element 345, and the optical sensor 210.
  • the virtual, direct view camera 215 may be formed directly in front of the eye 115. Detailed descriptions of the light propagation and other elements can refer to the above descriptions rendered in connection with FIG. 3A.
  • FIG. 7A illustrates a schematic three-dimensional (“3D”) view of a liquid cry stal polarization hologram (“LCPH”) device or element 700 with a light 702 incident onto the LCPH element 700 along a -z-axis, according to an embodiment of the present disclosure.
  • the LCPH element 700 described herein may be fabricated based on various methods, such as holographic interference, laser direct writing, ink-jet printing, and various other forms of lithography.
  • a “hologram” described herein is not limited to fabrication by holographic interference, or “holography.”
  • the LCPH element 700 may include a thin layer (or film) 715 of one or more birefringent materials with intrinsic or induced (e.g., photo-induced) optical anisotropy, such as liquid cry stals, liquid cry stal polymers, amorphous polymers.
  • a thin layer 715 may also be referred to as a birefringent medium layer (or film) or an LCPH layer (or film) 715.
  • the birefringent medium layer 715 may have a first surface 715-1 on one side and a second surface 715-2 on an opposite side.
  • the first surface 715-1 and the second surface 715-2 may be surfaces along the light propagating path of the incident light 702.
  • the birefringent medium layer 715 may be a polymer layer including a birefringent photo-refractive holographic material other than LCs, such as an amorphous polymer.
  • LCPH may encompass polarization holograms based on LCs and polarization holograms based on birefringent photo-refractive holographic materials other than LCs.
  • an optic axis of the birefringent medium layer 715 may be configured with a spatially varying orientation in at least one in-plane direction.
  • the in-plane direction may be an in-plane linear direction (e.g.. an x-axis direction, ay-axis direction), an in-plane radial direction, an in-plane circumferential (e.g., azimuthal) direction, or a combination thereof.
  • the optic axis of the birefringent medium layer 715 may also be configured with a spatially vary ing orientation in an out-of-plane direction.
  • the optic axis of the birefringent medium layer 715 may twist in a helical fashion in the out-of-plane direction.
  • the term ‘'optic axis” may refer to a direction in a crystal. A light propagating in the optic axis direction may not experience birefringence (or double refraction). An optic axis may be a direction rather than a single line: lights that are parallel to that direction may experience no birefringence.
  • the local optic axis may refer to an optic axis within a predetermined region of a crystal.
  • the birefringent medium layer 715 may include optically anisotropic molecules (e.g., LC molecules) configured with a three-dimensional (“3D”) orientational pattern to provide a polarization selective optical response.
  • optically anisotropic molecules e.g., LC molecules
  • 3D three-dimensional
  • the orientation of the optic axis of the birefringent medium layer 715 may be configured through configuring the local orientation of directors of the optically anisotropic molecules in the birefringent medium layer 715.
  • FIG. 7B schematically illustrates an x-y sectional view of in-plane orientations of the optically anisotropic molecules 712 in the LCPH element 700, according to an embodiment of the present disclosure.
  • the in-plane orientations of the optically anisotropic molecules 712 in the LCPH element 700 shown in FIG. 7B are for illustrative purposes.
  • the optically anisotropic molecules 712 in the LCPH element 700 may have other in-plane orientation patterns.
  • rod-like LC molecules 712 are used as examples of the optically anisotropic molecules 712 of the birefringent medium layer 715.
  • the rod-like LC molecule 712 may have a longitudinal axis (or an axis in the length direction) and a lateral axis (or an axis in the width direction).
  • the longitudinal axis of the LC molecule 712 may be referred to as a director of the LC molecule 712 or an LC director.
  • ) of the LC director may determine a local optic axis orientation or an orientation of the optic axis at a local point of the birefringent medium layer 715.
  • FIG. 7B shows that orientations of the LC directors (indicated by arrows 788 in FIG. 7B) of the LC molecules 712 located in close proximity to a surface (e.g., at least one of the first surface 715-1 or the second surface 715-2) of the birefringent medium layer 715 may exhibit a periodic rotation in a predetermined in-plane direction, e.g., an x-axis direction in FIG. 7B.
  • the continuous rotation of orientations of the LC directors may form a periodic rotation pattern with a uniform (e.g., same) in-plane pitch Pin.
  • the in-plane pitch Pin is defined as a distance along the in-plane direction (e.g., the y-axis direction) over which the LC directors rotate by a predetermined value (e.g., 180°) from a predetermined initial state (or reference state).
  • the periodic in-plane orientation pattern with the uniform (or same) in-plane pitch Pin shown in FIG. 7A may correspond to a grating pattern.
  • the LCPH element 700 may function as a polarization selective grating, e.g., a PVH grating, or a PBP grating, etc.
  • the orientations of the directors of the LC molecules 712 may exhibit a rotation in a predetermined rotation direction, e.g., a clockwise direction or a counter-clockwise direction. Accordingly, the rotation of the orientations of the directors of the LC molecules 712 located in close proximity to the surface of the birefringent medium layer 715 may exhibit a handedness, e.g., right handedness or left handedness.
  • the orientations of the directors of the LC molecules 712 located in close proximity to the surface of the birefringent medium layer 715 may exhibit a rotation in a clockwise direction. Accordingly, the rotation of the orientations of the directors of the LC molecules 712 located in close proximity to the surface of the birefringent medium layer 715 may exhibit a left handedness.
  • the orientations of the directors of the LC molecules 712 located in close proximity to the surface of the birefringent medium layer 715 may exhibit a rotation in a counter-clockwise direction. Accordingly, the rotation of the orientations of the directors of the LC molecules 712 in regions located in close proximity to or at the surface of the birefringent medium layer 715 may exhibit a right handedness.
  • domains in which the orientations of the directors of the LC molecules 712 exhibit a rotation in a clockwise direction may be altematingly arranged in at least one in-plane direction, e.g., a first (or x-axis) in-plane direction and/or a second (or y-axis) in-plane direction.
  • FIGs. 7C-5F schematically illustrate y-z sectional views of a portion of the LCPH element 700, showing out-of-plane orientations of the LC directors of the LC molecules 712 in the LCPH element 700, according to various embodiments of the present disclosure.
  • the LC molecules 712 may be arranged in a plurality of helical structures 717 with a plurality of helical axes 718 and a helical pitch Ph along the helical axes (Ph may be related to vertical pitch P v described below).
  • the orientations of the LC directors of the LC molecules 712 arranged along a single helical structure 717 may exhibit a continuous rotation around the helical axis 718 in a predetermined rotation direction. Accordingly, the helical structure 717 may exhibit a handedness, e.g., right handedness or left handedness.
  • the helical pitch Ph may be defined as a distance along the helical axis 718 over which the orientations of the LC directors exhibit a rotation around the helical axis 718 by 360°. or the azimuthal angles of the LC molecules vary by 360°.
  • the helical axes 718 may be substantially perpendicular to the first surface 715-1 and/or the second surface 715-2 of the birefringent medium layer 715.
  • the helical axes 718 of the helical structures 717 may be in a thickness direction (e.g.. a z-axis direction) of the birefringent medium layer 715.
  • the LC molecules 712 may have substantially small tilt angles (including zero degree tilt angles), and the LC directors of the LC molecules 712 may be substantially orthogonal to the helical axis 718.
  • the birefringent medium layer 715 may also have a vertical pitch P v , which may be defined as a distance along the thickness direction of the birefringent medium layer 715 over which the orientations of the LC directors of the LC molecules 712 exhibit a rotation around the helical axis 718 by 180° (or the azimuthal angles of the LC directors vary by 180°).
  • the vertical pitch Pv may be half of the helical pitch Ph.
  • the LC molecules 712 from the plurality of helical structures 717 having a first same orientation may form a first series of parallel refractive index planes 714 periodically distributed within the volume of the birefringent medium layer 715.
  • the LC molecules 712 with a second same orientation e.g., same tilt angle and azimuthal angle
  • Different series of parallel refractive index planes may be formed by the LC molecules 712 having different orientations.
  • the LC molecules 712 may have the same orientation and the refractive index may be the same.
  • Different series of refractive index planes 714 may correspond to different refractive indices.
  • Bragg diffraction may be established according to the principles of volume gratings.
  • the periodically distributed refractive index planes 714 may also be referred to as Bragg planes 714.
  • the refractive index planes 714 may be slanted with respect to the first surface 715-1 or the second surface 715-2. In some embodiments, the refractive index planes 714 may be perpendicular to or parallel with the first surface 715-1 or the second surface 715-2. Within the birefringent medium layer 715, there may exist different series of Bragg planes. A distance (or a period) between adjacent Bragg planes 714 of the same series may be referred to as a Bragg period PB.
  • the different series of Bragg planes formed within the volume of the birefringent medium layer 715 may produce a varying refractive index profile that is periodically distributed in the volume of the birefringent medium layer 715.
  • the birefringent medium layer 715 may diffract an input light satisfying a Bragg condition through Bragg diffraction.
  • the birefringent medium layer 715 may also include a plurality of LC molecule director planes (or molecule director planes) 716 arranged in parallel with one another within the volume of the birefringent medium layer 715.
  • An LC molecule director plane (or an LC director plane) 716 may be a plane formed by or including the LC directors of the LC molecules 712.
  • the LC directors in the LC director plane 716 have different orientations, i.e., the orientations of the LC directors vary in the x-axis direction.
  • the Bragg plane 714 may form an angle 0 with respect to the LC molecule director plane 716.
  • FIG. 7C the embodiment shown in FIG.
  • the angle 0 may be an acute angle, e.g., 0° ⁇ 0 ⁇ 90°.
  • the LCPH element 700 including the birefringent medium layer 715 show n in FIG. 7C may function as a transmissive PVH element, e.g., a transmissive PVH grating.
  • the helical axes 718 of helical structures 717 may be tilted with respect to the first surface 715-1 and/or the second surface 715-2 of the birefringent medium layer 715 (or with respect to the thickness direction of the birefringent medium layer 715).
  • the helical axes 718 of the helical structures 717 may have an acute angle or obtuse angle with respect to the first surface 715-1 and/or the second surface 715-2 of the birefringent medium layer 715.
  • the LC directors of the LC molecule 712 may be substantially orthogonal to the helical axes 718 (i.e., the tilt angle may be substantially zero degree). In some embodiments, the LC directors of the LC molecule 712 may be tilted with respect to the helical axes 718 at an acute angle.
  • the birefringent medium layer 715 may have a vertical periodicity (or pitch) P v . In the embodiment shown in FIG. 7D, an angle 0 (not shown) between the LC director plane 716 and the Bragg plane 714 may be substantially 0° or 180°. That is, the LC director plane 716 may be substantially parallel with the Bragg plane 714. In the example shown in FIG.
  • the orientations of the directors in the molecule director plane 716 may be substantially the same.
  • the LCPH element 700 including the birefringent medium layer 715 shown in FIG. 7D may function as a reflective PVH element, e.g., a reflective PVH grating.
  • the birefringent medium layer 715 may also include a plurality of LC director planes 716 arranged in parallel within the volume of the birefringent medium layer 715.
  • the LC directors in the LC director plane 716 may have different orientations.
  • the LCPH element 700 including the birefringent medium layer 715 shown in FIG. 7E may function as a transmissive PVH element, e.g., a transmissive PVH grating.
  • the directors (or the azimuth angles) of the LC molecules 712 may remain in the same orientation (or same angle value) from the first surface 715-1 to the second surface 715- 2 of the birefringent medium layer 715.
  • the LCPH element 700 including the birefringent medium layer 715 shown in FIG. 7F may function as a PBP element, e.g., a PBP grating.
  • FIG. 8A illustrates diffraction orders of the LCPH element 700 functioning as a transmissive PVH element 800, according to an embodiment of the present disclosure.
  • the transmissive PVH element 800 may be configured to primarily forwardly diffract a circularly polarized light having a predetermined handedness as a diffracted light of a certain order (e.g., the 1 st diffracted light).
  • the transmissive PVH element 800 may primarily transmit (e.g., with negligible diffraction) a circularly polarized light having a handedness that is opposite to the predetermined handedness as a transmitted light (the 0 th order).
  • the transmissive PVH element 800 may be configured to reverse the handedness of the circularly polarized light diffracted thereby.
  • the diffracted light output from the transmissive PVH element 800 may be a circularly polarized light with a handedness reversed by the transmissive PVH element 800.
  • the transmissive PVH element 800 may be configured to maintain the handedness of the circularly polarized light transmitted thereby. For discussion purposes, FIG.
  • the transmissive PVH element 800 shows the transmissive PVH element 800 as a right-handed transmissive PVH, which is configured to primarily forwardly diffract an RHCP light 830 as an LHCP light 840, and primarily transmit (e.g., with negligible diffraction) an LHCP light 835 to the 0 th order as an LHCP light 845.
  • the transmissive PVH element 800 may change the polarization of the diffracted light and/or transmitted light.
  • FIG. 8B illustrates diffraction orders of the LCPH element 700 functioning as a reflective PVH element 850, according to an embodiment of the present disclosure.
  • the reflective PVH element 850 may be configured to primarily backwardly diffract a circularly polarized light having a predetermined handedness as a diffracted light of a certain order (e.g., the 1 st diffracted light), and primarily transmit (e.g., with negligible diffraction) a circularly polarized light having a handedness that is opposite to the predetermined handedness as a transmitted light (the 0 th order).
  • the reflective PVH element 850 may be configured to substantially maintain the handedness of the circularly polarized light diffracted thereby and the handedness of the circularly polarized light transmitted thereby.
  • the diffracted light may be a circularly polarized light with a handedness substantially maintained by the reflective PVH element 850
  • the transmitted light may be a circularly polarized light with a handedness substantially maintained by the reflective PVH element 850.
  • FIG. 8B shows that the reflective PVH element 850 is a right-handed reflective PVH, which is configured to primarily backwardly diffract an RHCP light 830 as an RHCP light 860, and primarily transmit (e.g., with negligible diffraction) an LHCP light 835 to the 0 th order as an LHCP light 865.
  • the reflective PVH element 850 may change the polarization of the diffracted light and/or transmitted light.
  • the present disclosure provides a system.
  • the system includes a light source configured to emit a infrared (“IR”) light for illuminating an object.
  • IR infrared
  • the system also includes a waveguide imaging assembly including a waveguide, an incoupling element disposed at a first portion of the waveguide, an out-coupling element disposed at a second portion of the waveguide, and an optical sensor disposed facing the out- coupling element.
  • the in-coupling element is configured to couple the IR light reflected by the object into the waveguide
  • the waveguide is configured to guide the IR light to propagate toward the out-coupling element through total internal reflection
  • the out-coupling element is configured to couple the IR light out of the waveguide toward the optical sensor
  • the optical sensor is configured to generate a tracking signal of the object based on the IR light output from the waveguide.
  • the in-coupling element and the out-coupling element are configured to deflect the IR light, and substantially transmit, with negligible deflection, a visible light.
  • the waveguide is configured to guide the IR light to propagate toward the out-coupling element along a width direction of the waveguide via total internal reflection, and along the width direction of the waveguide, a width of the in-coupling element is configured to be at a sub-millimeter level.
  • the width of the in-coupling element is configured to be 200-300 micrometers, 300-400 micrometers, 400-500 micrometers, or 500-600 micrometers.
  • the optical sensor is disposed off-axis with respect to the object.
  • at least one of the in-coupling element or the out-coupling element includes a diffraction grating.
  • the in-coupling element is a first in-coupling element
  • the out-coupling element is a first out-coupling element
  • the system further include a second in-coupling element disposed at the second portion of the waveguide, and a second out-coupling element disposed at the first portion of the waveguide.
  • the second in-coupling element and the second out-coupling element are configured to deflect a visible light, and substantially transmit, with negligible deflection, the IR light.
  • the second in-coupling element is configured to couple the visible light representing a virtual image into the waveguide as an in-coupled visible light that propagates inside the waveguide via total internal reflection
  • the second out-coupling element is configured to couple the in-coupled visible light out of the waveguide as one or more output visible lights toward an eye-box region of the system.
  • a width of the first in-coupling element is smaller than a width of the second out- coupling element.
  • the light source is a first light source
  • the system further includes a second light source disposed facing the second portion of the waveguide, and configured to output the visible light toward the second in-coupling element.
  • the in-coupling element is a first in-coupling element
  • the out-coupling element is a first out-coupling element
  • the waveguide is a first waveguide
  • the system further includes a second wav eguide stacked with the first waveguide, a second out-coupling element disposed at a first portion of the second waveguide, and a second incoupling element disposed at a second portion of the second waveguide.
  • the second incoupling element and the second out-coupling element are configured to deflect a visible light, and substantially transmit, with negligible deflection, the IR light.
  • the second in-coupling element is configured to couple the visible light representing a virtual image into the second waveguide as an in-coupled visible light that propagates inside the second waveguide via total internal reflection
  • the second out- coupling element is configured to couple the in-coupled visible light out of the second waveguide as one or more output visible lights toward an eye-box region of the system.
  • a width of the first incoupling element is smaller than a width of the second out-coupling element.
  • the light source is a first light source
  • the system further includes a second light source disposed facing the second portion of the second waveguide, and configured to output the visible light toward the second in-coupling element.
  • the optical sensor and the object are disposed at the same side of the waveguide. In some embodiments, the optical sensor and the object are disposed at different sides of the waveguide.
  • a conventional waveguide (or light guide) display system may include a light source assembly that emits an image light representing a virtual image, and a waveguide (or light guide) that guides the image light to an eye-box region.
  • the waveguide may be provided with a plurality of couplers or coupling elements that couple the image light into the waveguide and out of the waveguide toward the eye-box region.
  • the couplers used in a geometric waveguide display system may include partially reflective couplers, whereas the couplers used in a diffractive waveguide display system may include gratings.
  • the waveguide may also receive a visible polychromatic light coming from a real- world environment (referred to as a real- orld light).
  • the real-world light incident onto the waveguide at a large skew angle range may also be coupled into the waveguide.
  • the couplers may diffract, refract, and/or reflect the real-world light, causing a multicolored glare in a see-through view, especially when a user wearing the artificial reality device looks at a bright light source from certain angles.
  • Such a see-through artifact is referred to as a “rainbow effect” or a “world side ghost”, which may degrade the image quality of the see- through view'.
  • the rainbow effect may result from a light dispersion caused by the coupler, as the coupler spatially separates, e.g., via diffraction, reflection, and/or refraction, the real- world light into constituent w avelength components.
  • Each wavelength of the incident light spectrum may be directed to a different direction, producing a rainbow of colors under a white light illumination.
  • FIG. 9A illustrates an x-y sectional view' of a conventional geometric w aveguide display system 900.
  • the system 900 may include a light source assembly (not shown) that emits an image light representing a virtual image (referred to as an input image light), and a waveguide 910 that guides the input image light to an exit pupil 957 in an eye-box region 959 where an eye 960 of a user is positioned.
  • the waveguide 910 may include an input coupler 905 that couples the input image light as an in-coupled image light 932 propagating inside the waveguide 910 via total internal reflection (“TIR”).
  • TIR total internal reflection
  • the waveguide 910 may also include a plurality of partially reflective mirrors 940 embedded in the w aveguide 910.
  • the mirrors 940 may include a first array of mirrors 940-1 (referred to as folding mirrors 940-1) located at a first portion 921 of the w aveguide 910, and a second array of mirrors 940-2 (referred to as out-coupling mirrors 940-2) located at a second portion 922 of the waveguide 910.
  • the folding mirrors 940-1 may expand the input image light in a first direction
  • the out-coupling mirrors 940-2 may expand the input image light in a second direction.
  • the system 900 may provide a two-dimensional expansion of the input image light at the eye-box region 959.
  • the in-coupled image light 932 may propagate inside the waveguide 910 along the first direction via TIR, toward the folding mirrors 940-1.
  • the folding mirrors 940-1 may split (via reflection) the in-coupled image light 932 as a plurality 7 of redirected image lights 932 propagating inside the w aveguide 910 along a second direction via TIR, toward the out-coupling mirrors 940-2.
  • the out-coupling minors 940-2 may couple the redirected image lights 932 out of the waveguide 910 as a plurality of output image lights 934 distributed along both the first direction and the second direction.
  • FIG. 9B illustrates an x-z sectional view of a portion of the conventional geometrical waveguide display system 900 shown in FIG. 9A, showing a rainbow effect perceived at the eye-box region 959 of the system 900.
  • the mirrors 940 embedded in the waveguide 910 may also reflect a real-world light 952 toward the eyebox region 959.
  • the waveguide 910 may have a first side or surface 910-1 (also referred to as a front surface 910-1) facing the eye-box region 959 and a second side or surface 910-2 facing the real -world environment (also referred to as a back surface 910-2).
  • the real-world light 952 may be incident onto the second surface 910-2 of the waveguide 910.
  • the mirrors 940 may spatially separate the real-w orld light 952 into constituent wavelength components propagating in different directions, e.g., a red wavelength component 952R, a green wavelength component 952G, and a blue wavelength component 952B at the eye-box region 959, causing a '‘rainbow effect” or a “world side ghost” in a see-through view.
  • FIGs. 10A and 10B illustrate an optical path of a real-world light 952-1 (represented by dashed arrow) that generates the first type of rainbow at the eye-box region 959, and an optical path of the incoupled image light 932 (represented by solid arrows) from the folding mirrors 940-1 to the eye-box region 959.
  • FIG. 10A illustrates an optical path of a real-world light 952-1 (represented by dashed arrow) that generates the first type of rainbow at the eye-box region 959, and an optical path of the incoupled image light 932 (represented by solid arrows) from the folding mirrors 940-1 to the eye-box region 959.
  • FIG. 10A illustrates a cross-sectional view of the folding mirrors 940-1 along the first direction shown in FIG. 9A, and an enlarged view of a folding mirror 940-1.
  • the folding mirror 940-1 may have a front surface 961 facing the eyebox region 959, and a back surface 962 facing the real world environment.
  • FIG. I OB illustrates a cross-sectional view of the out-coupling mirrors 940-2 along the second direction shown in FIG. 9A, and an enlarged view of an out-coupling mirror 940-2.
  • the out-coupling mirror 940-2 may have a front surface 971 facing the ey e-box region 959, and a back surface 972 facing the real world environment.
  • the mirrors (folding or out-coupling) 940 are embedded inside the waveguide 910, and are slanted with respect to a surface of the waveguide 910.
  • the real -world light 952-1 (represented by dashed arrow ) may be incident onto a portion of the waveguide 910 where the folding mirrors 940-1 are embedded.
  • the real -world light 952-1 may be incident onto the back surface 962 of the folding mirror 940-1, and may be coupled into a TIR propagation path inside the w aveguide 910 via the folding mirror 940-1.
  • the real-w orld light 952-1 propagating inside the w aveguide 910 via TIR may be incident onto the front surface 971 of the out-coupling mirror 940-2, as shown in FIG. 10B.
  • the out-coupling mirror 940-2 may couple the real-world light 952-1 out of the waveguide 910 as a real-world light 954-1 , as shown in FIG. 10B.
  • the folding mirror 940-1 and the out-coupling mirror 940-2 may spatially separate the real-world light 952-1 into constituent wavelength components propagating in different directions toward the eye-box region 959, causing the first type of rainbow (or first type of world side ghost) in a see-through view.
  • the first type of rainbow may be caused by the real-world light 952-1 that is coupled into the TIR propagation path inside the waveguide 910 from the back surface of the folding mirror 940-1, and that is coupled out of the waveguide 910 from the front surface 971 of the out-coupling mirror 940-2.
  • the intensity of the real-world light 954-1 output from the w aveguide 910 may be about 0.4% of the intensity of the real-world light 952-1 entering the w aveguide 910. That is, the efficiency of the first ty pe of rainbow (or first ty pe of w orld side ghost) is about 0.4% at the eye-box region 959.
  • the inventors also observed that when the AOI of a real-world light 952-3 at the out-coupling mirrors 940-2 is substantially small (e.g., smaller than 30°), the out-coupling mirrors 940-2 may reflect the real-world light 952-3 toward the eye-box region 959, and the rainbow effect caused by the reflected real-world light 952-3 may be substantially weak and negligible at the eye-box region 959.
  • the AOI of the real-world light 952-3 at the out- coupling mirrors 940-2 is large (e.g., larger than 60°)
  • the out-coupling mirrors 940-2 may reflect the real-world light 952-3, with a strong rainbow effect.
  • the out-coupling mirrors 940-2 may substantially reflect the real-world light 952-3 to a direction outside of the FOV of the system 900. That is. the reflected real-world light 952-3 may not be perceived by the eye 960 located within the eye-box region 959 and, accordingly, the rainbow effect caused by the reflected real-world light 952-3 may not be perceived by the eye 960 located within the eye-box region 959.
  • FIG. 10C illustrates a cross-sectional view of the folding mirrors 940-1 along the first direction shown in FIG. 9A, showing an optical path of a real-world light 952-2 (represented by a dashed arrow) that generates the second type of rainbow at the eye-box region 959.
  • the real-world light 952-2 may be incident onto the back surface 962 of the folding mirror (referred to as a first folding mirror) 940-1, and coupled into a TIR propagation path inside the waveguide 910 via the first folding mirror 940-1.
  • the real-world light 952-2 coupled into propagating inside the waveguide 910 via TIR may be incident onto the front surface 961 of another folding mirror (referred to as a second folding mirror) 940-1, and coupled out of the waveguide 910 via the second folding mirror 940-1 as a real-world light 954-2 propagating toward the eye-box region 959.
  • the first and the second folding mirrors 940-1 may spatially separate the real-world light 952-2 into constituent wavelength components propagating in different directions toward the eye-box region 959, causing the second type of rainbow (or second ty pe of world side ghost) in a see-through view.
  • the second type of rainbow (or second type of world side ghost) may be caused by the real-world light 952-2 that is coupled into the TIR propagation path inside the waveguide 910 at the front surface, double reflected by the folding mirror 940-1, and coupled out of the waveguide 910 via the folding mirror 940-1.
  • the intensity of the real-world light 954-2 output from the waveguide 910 may be about 0. 1% of the intensity of the real-world light 952-2 entering the waveguide 910. That is, the efficiency of the second type of rainbow (or second ty pe of w orld side ghost) is about 0.01% at the eye-box region 959.
  • FIG. 10D illustrates simulation results showing AOI ranges of the real-world lights 952-1 and 952-2 and the in-coupled image light 932 at the folding mirror 940-1.
  • the horizontal axis represents AOI (unit: degree (°)).
  • a bar 981 shows that an AOI range of the image light 932 at the front surface 961 of the folding mirror 940-1 is from 31.31° to 50.8°.
  • a bar 982 shows that an AOI range of the real-world light 952-1 at the front surface 961 of the folding mirror 940-1 is from 21.71° to 52.52°.
  • a bar 983 show s that an AOI range of the real-world light 952-2 at the back surface 962 of the folding mirror 940- 1 is from 48.76° to 55.4°.
  • a bar 984 shows that an AOI range of the real-world light 952-2 at the front surface 961 of the folding mirror 940-1 is from 64.35° to 70.09°.
  • the bars 981-983 at least partially overlap with one another, indicating that the AOI range of the image light 932 at the front surface 961, the AOI range of the real-world light 952-1 at the front surface 961, and the AOI range of the real- world light 952-2 at the back surface 962 at least partially overlap with one another.
  • the bar 984 does not overlap with any of the bars 981-183, which indicates that the AOI range of the real -w orld light 952-2 at the front surface 961 does not overlap with any of the AOI range of the image light 932 at the front surface 961, the AOI range of the real-world light 952-1 at the front surface 961, and the AOI range of the real-w orld light 952-2 at the back surface 962.
  • the AOI range of the real-world light 952-2 at the front surface 961 can be distinguished from each of the AOI range of the image light 932 at the front surface 961, the AOI range of the real-world light 952-1 at the front surface 961, and the AOI range of the real-world light 952-2 at the back surface 962.
  • FIG. 10E illustrates simulation results showing AOI ranges of the real-world lights 950-1 and 950-2 and the in-coupled image light 932 at the out-coupling mirror 940-2.
  • the horizontal axis represents AOI (unit: degree (°)).
  • a bar 991 shows that an AOI range of the image light 932 at the front surface 971 of the out-coupling mirror 940-2 is from 17.53° to 32.8°.
  • a bar 992 show s that an AOI range of the real-w orld light 952-1 at the front surface 971 of the out-coupling mirror 940-2 is from 17.56° to 50.03°.
  • the bars 991 and 992 at least partially overlap with one another, indicating that the AOI range of the image light 932 at the front surface 971 and the AOI range of the real-world light 952-1 at the front surface 971 at least partially overlap with one another.
  • the AOI range of the image light 932 at the front surface 971 may not be distinguished from the AOI range of the real -world light 952-1 at the front surface 971.
  • FIG. 10F illustrates simulation results showing angular positions of the first type of rainbow (or first type of world side ghost) and the second type of rainbow (or second type of world side ghost) within a field of view (“FOV”) at the output side of the waveguide 910.
  • the horizontal axis represents horizontal FOV direction (unit: degree (°))
  • the vertical axis represents a vertical FOV direction (unit: degree (°)).
  • the eye 960 is presumed to be at a location where both the horizontal FOV direction and the vertical FOV direction are zero degree.
  • the negative vertical FOV directions correspond to angles above the horizontal plane (or transverse plane) of the eye 960
  • the positive vertical FOV directions correspond to angles below the horizontal plane of the eye 960.
  • the negative horizontal FOV directions correspond to angles to the left of the sagittal plane (or lateral plane) of the eye 960
  • the positive horizontal FOV directions correspond to angles to the right of the median plane of the eye 960.
  • the first type of world side ghost has a vertical angular position ranging from about -90° to about -30° and a horizontal angular position ranging from about -70° to about -20°, as indicated by a circle 1005.
  • the second type of world side ghost has a vertical angular position ranging from about 80° to about 40° and a horizontal angular position ranging from about -70° to about -40°, as indicated by a circle 1010.
  • the efficiency of the world side ghost is represented by grey scales, in which the darker grey indicates a lower efficiency, and the lighter grey indicates a higher efficiency.
  • the first type of world side ghost has a larger angular position range and a higher efficiency than the second type of world side ghost.
  • FIG. 11 A illustrates an x-y sectional view of a waveguide display system 1100 (referred to as system 1100 for simplicity) configured to reduce a rainbow effect, according to an embodiment of the present disclosure.
  • the system 1100 may be implemented into an artificial reality device or system for AR and/or MR applications.
  • the system 1100 may be a geometric waveguide display system.
  • the system 1100 may include a controller (not shown), a light source assembly (not shown) that emits an image light representing a virtual image (referred to as an input image light), and a waveguide 11 10 that guides the input image light to an eye-box region 1159 where an eye 1160 of a user is positioned.
  • a controller not shown
  • a light source assembly not shown
  • a waveguide 11 10 that guides the input image light to an eye-box region 1159 where an eye 1160 of a user is positioned.
  • the light source assembly may include a display element (e g., micro-projector) and a collimating lens.
  • the display element may include a plurality’ of pixels arranged in a pixel array, in which neighboring pixels may be separated by, e.g., a black matrix.
  • the display element may output an image light, which includes bundles of divergent rays output from the respective pixels.
  • the collimating lens may convert the bundles of divergent rays in the image light output from the display element into bundles of parallel rays in the input image light propagating toward the waveguide 11 10.
  • the respective bundles of parallel rays may have different incidence angles at the waveguide 1110. That is, the collimating lens may transform or convert a linear distribution of the pixels in the display element into an angular distribution of the pixels at the input side of the waveguide 1110.
  • the waveguide 1110 may include a plurality of couplers embedded in the waveguide 1110, such as an in-coupling element 1135 embedded at a first portion 1111 (e.g., input portion) of the waveguide 1110, a folding or redirecting element 1140 embedded at a second portion 1112 of the waveguide 1110. and an out-coupling element 1145 embedded at a third portion 1113 (e.g., output portion) of the waveguide 1 110 where the eye-box region 1159 is located.
  • the second portion 1112 may be located between the first portion 1111 and the third portion 1113 of the waveguide 1110.
  • the eye-box region 1159 may not overlap with the in-coupling element 1135 or the folding element 1140.
  • the in-coupling element 1135 may be configured to couple the input image light as an in-coupled image light 1132 propagating inside the waveguide 1110 via TIR.
  • the in-coupling element 1135 may include a highly reflective mirror.
  • the in-coupling element 1135 may not be embedded in the waveguide 1110. Instead, the in-coupling element 1135 may be disposed at a surface of the waveguide 1110.
  • the in-coupling element 1135 may include a prism disposed at a surface of the waveguide 1110.
  • the folding element 1140 may include an array of transflective elements (or partial reflectors) 1140a. referred to as folding mirrors 1140a for discussion purposes.
  • the out-coupling element 1145 may include an array of transflective elements (or partial reflectors) 1145a, referred to as out-coupling mirrors 1145a for discussion purposes.
  • a transflective element (or partial reflector) may be a facet having a transflective surface (or partial reflective surface) that reflects a first portion of an incident light and transmits a second portion of the incident light.
  • the transmittance and the reflectance of the transflective element may be configurable depending on different applications.
  • the transmittance and the reflectance of the folding mirror 1140a may be configured to be about 85% and 15%, respectively.
  • the transmittance and reflectance of the folding mirror 1140a may be the same as or different from the transmittance and reflectance of the out-coupling mirror 1 145a.
  • the in-coupled image light 1132 may propagate inside the waveguide 1110 toward the redirecting element 1140 via TIR along a first direction shown in FIG. HA (which is a first pupil expansion or replication direction). As shown in FIG.
  • each folding mirror 1140a may reflect a portion of the in-coupled image light 1132 as a redirected image light 1132 (indicated by a dashed arrow) propagating in a second direction as shown in FIG. 11 A. and transmit the rest of the in-coupled image light 1132 for further TIR propagation along the first direction toward a next folding mirror 1140a.
  • the array of folding mirrors 1140a may split the in-coupled image light 1132 into a plurality of redirected image lights 1132 (indicated by dashed arrows) propagating inside the waveguide 1110 along different parallel paths in the second direction, toward the array of out-coupling mirrors 1145a.
  • the redirecting element 1 140 or the array of folding mirrors 1140a may expand the input image light received from the light source assembly in the first direction as shown in FIG. 11 A.
  • FIG. 11 A shows four redirected image lights 1132 (denoted by dashed arrows) propagating inside the waveguide 1110 along different paths in the second direction, and a central ray of the respective redirected image light 1132.
  • the array of out-coupling mirrors 1145a may receive the redirected image lights 1132 from the array of folding mirrors 1140a.
  • each out-coupling mirror 1145a may couple, via reflection, a portion of the redirected image light 1 132 out of the waveguide 11 10 as an output image light 1134, and transmit the rest of the redirected image light 1132 for further TIR propagation along the second direction toward a next out-coupling mirror 1145a.
  • each redirected image light 1132 may be reflected by the array of out-coupling mirrors 1145a as a plurality of output image lights 1134 distributed along the second direction as shown in FIG.
  • FIG. 11A (which is a second pupil expansion direction).
  • the array of out-coupling mirrors 1145a may expand the input image light received from the light source assembly in the second direction as shown in FIG. 11A.
  • FIG. 11A merely illustrates five output image lights 1134. and a central ray of the respective output image light 1134.
  • the waveguide 1110 with the embedded out-coupling element 1145 and redirecting element 1140 may provide a first beam expansion long the first direction and a second beam expansion long the second direction, thereby realizing the 2D pupil replication at the output side of the waveguide 11 10.
  • the output image lights 1134 may be distributed along both the first direction and the second direction.
  • the output image lights 1134 may propagate toward a plurality of exit pupils 1157 located within the eye-box region 1159 of the waveguide display system 1100.
  • An exit pupil 1157 is a region in space where an eye pupil 1158 of an eye 1160 of a user is positioned in the eye-box region 1159 to receive the content of a virtual image output from the display element.
  • the exit pupils 1157 may be arranged in a two-dimensional (‘“2D”) array within the eye-box region 1159.
  • the eye-box region 1159 overlaps with all, or most, of the possible positions of the eye pupil 1158 of the user.
  • This feature referred to as "pupil expansion,” creates the effect of a full real-life image as perceived by the user, rather than a moving eye pupil characteristic provided by other viewing instruments (e.g., binoculars, microscopes, or telescopes).
  • the folding mirror 1140a may be configured to be an angularly selective mirror, and the system 1100 may be configured to reduce the second type of world side ghost (or rainbow) via configuring an angular selectivity of the folding mirror 1140a.
  • the AOI range of the real-world light 952-2 at the front surface 961 of the folding mirror 940-1 is from 64.35° to 70.09°, which does not overlap with any of the AOI range of the image light 932 at the front surface 961, the AOI range of the real-world light 952-1 at the front surface 961, and the AOI range of the real-world light 952-2 at the back surface 962.
  • the real-world light 952-2 may be diverted from propagating toward the eye-box region 1159. whereas the optical path of the image light 1132 inside the waveguide 1 1 10 may not be affected. Accordingly, the second type of world side ghost (or rainbow) may be reduced at the eye-box region 1159.
  • FIG. 1 IB illustrates a cross-sectional view of a portion of the waveguide 1110 along the first direction shown in FIG. 11 A, showing an optical path of the real -world light 952-2 (represented by a dashed arrow), and an optical path of the in-coupled image light 1 132 (represented by solid arrows) inside the w aveguide 1110.
  • FIG. 11C illustrates a cross- sectional view of a portion of the w aveguide 1110 along the second direction shown in FIG. 11 A, showing an optical path of the in-coupled image light 1132 (represented by solid arrows) inside the waveguide 11 10.
  • FIG. 1 ID illustrates a cross-sectional view of the folding mirror 1140a along the first direction in FIG. 11 A. As shown in FIG. 1 ID, the folding mirror 1140a may have a front surface 1161 facing the eye-box region 1159, and a back surface 1162 facing the real world environment.
  • the folding mirror 1140a may be configured to be angular selective.
  • the folding mirror 1140a may be configured to partially reflect or substantially transmit an incident light, depending on an AOI of the incident light at the front surface 1161 of the folding mirror 1140a shown in FIG. 1 ID.
  • the folding mirror 1140a may be configured to substantially transmit the incident light (with a substantially high transmittance, e.g.. above 95%).
  • the folding mirror 1140a may be configured to partially reflect and partially transmit the incident light, e.g., with a 15% reflectance and 85% transmittance.
  • the folding mirror 1140a may also be referred to as an AOI cutoff coating, where the cutoff AOI is the first predetermined angle.
  • the folding mirror 1140a may include a dielectric multi-layer coating.
  • the waveguide 1110 may include a first side or surface 1110-1 facing the eye-box region 1159, and a second side or surface 1110-2 facing the real world environment.
  • the real-world light 952-2 may be incident onto the second side or surface 1 110-2 of the light guide 1110.
  • the AOI range of the real -world light 952-2 at the front surface 1161 of the folding mirror 1140a is from 64.35° to 70.09°
  • the AOI range of the in-coupled image light 1132 at the front surface 1161 of the folding mirror 1140a is from 31.31° to 50.8°.
  • the first predetermined angle may be configured to be between a maximum AOI of the AOI range of the in-coupled image light 1132 at the front surface 1 161 of the folding mirror 1140a and a minimum value of the AOI range of the real-world light 952-2 at the front surface 1161 of the folding mirror 1140a.
  • the first predetermined angle may be configured to be in a range from 55° to 65°, 55° to 60°, or 60° to 65°.
  • the folding mirror 1140a may substantially transmit the real-world light 952-2 that has been coupled into the TIR propagation path inside the waveguide 1110 toward the real world environment located outside of the second side 1110-2 of the waveguide 1110, whereas the in-coupled image light 1132 may still be partially reflected and partially transmitted.
  • the real-world light 952-2 (represented by a dashed arrow) may be incident onto the back surface 1162 of the folding mirror (referred to as a first folding mirror) 1140a, and coupled into the TIR propagation path inside the waveguide 1110 via the first folding mirror 1140a.
  • the real-world light 952-2 coupled into the TIR propagation path inside the waveguide 1110 may propagate inside the waveguide 1110 via TIR, and may be incident onto the front surface 1161 of another folding mirror (referred to as a second folding mirror) 1140a.
  • the second folding mirror 1 140a may substantially transmit the real-world light 952-2 that has been coupled into the TIR propagation path inside the waveguide 1110 toward the real world environment located outside of the second surface 1110-2 of the waveguide 1110, thereby diverting the real-world light 952-2 from propagating toward the out-coupling minor 1145a.
  • the real-world light 952-2 which otherwise would be incident onto the out-coupling mirror 1145a and coupled out of the waveguide 1110 via the out-coupling mirror 1145a toward the eye-box region 1159, may be substantially transmit toward the real world environment located outside of the second surface 1110-2 without reaching the out-coupling mirror 1145a.
  • FIG. 11 A show s that the second folding mirror 1140a substantially transmits the real-world light 952-2 that has been coupled into the TIR propagation path inside the waveguide 1110 as a real -world light 1154, which propagate toward the real world environment located outside of the second surface 1110-2 of the waveguide 1110.
  • the real- world light 1154 may not be incident onto the out-coupling mirror 1145a and, thus, may not be coupled out of the waveguide 1110 via the out-coupling mirror 1145a tow ard the eye-box region 1159.
  • the second t pe of w orld side ghost (or rainbow) caused by the dispersion of the real-world light 952-2 at the eye-box region 1159 may be significantly reduced.
  • the folding mirror 1140a may partially reflect and partially transmit the in-coupled image light 1132 incident thereon. That is, the optical path of the in-coupled image light 1132 inside the waveguide 1110 may not be affected by the angular selectivity of the folding mirror 1140a.
  • the in-coupled image light 1 132 may be coupled out of the w aveguide 1110 via the out-coupling mirrors 1145 a as the output image lights 1134 prorogating toward the eye-box region 1159.
  • the real -world light 952-3 incident onto the third portion 1113 of the waveguide 1110 where the array of the out-coupling mirrors 1145a are located may propagate through the waveguide 1110.
  • the eye 1160 located within the eye-box region 1 159 may perceive the virtual image superimposed with real-world image, with a reduced rainbow ⁇ effect and an enhanced image quality.
  • the folding mirror 1140a may be configured to be a polarization selective mirror, and the system 1100 may be configured to reduce both the first ty pe and second type of world side ghosts (or rainbows) via configuring the polarization selectivity of the folding mirror 1140a.
  • FIG. 1 IE illustrates a cross-sectional view of a portion of the waveguide 1110 along the first direction shown in FIG. 11 A. showing an optical path of the real-world light 952-2 (represented by a dashed arrow), and an optical path of the in-coupled image light 1132 (represented by solid arrows) inside the waveguide 1110.
  • FIG. 1 IF illustrates a cross-sectional view of a portion of the waveguide 1110 along the second direction shown in FIG. 11A, showing an optical path of the in-coupled image light 1132 (represented by solid arrows) inside the waveguide 1110.
  • the system 1100 may further include a polarizer 1150.
  • the polarizer 1150 is shown as separated from the waveguide 1110 for illustrative purposes. In practice, the polarizer 1150 may be disposed directly on the second surface 1110-2 facing the real world environment, or may be disposed at a distance or gap from the second surface 1 110-2 of the waveguide 1 110.
  • the polarizer 1150 may at least overlap with the second portion 1112 of the waveguide 1110 where the folding mirrors 1140a are embedded. In some embodiments, the polarizer 1150 may also overlap with the third portion 1113 of the waveguide 1110 where the out-coupling mirrors 1145a are embedded.
  • the polarizer 1150 may be configured to substantially transmit a light having a first polarization, and substantially block a light having a second polarization that is perpendicular to the first polarization, e.g., via absorption, or reflection, etc.
  • the first polarization and the second polarization may be two orthogonal circular polarizations or two orthogonal linear polarizations.
  • the folding mirror 1140a may be configured to selectively partially reflect or substantially transmit an incident light, depending on a polarization state of the incident light.
  • the folding mirror 1140a may be configured to substantially transmit the incident light (with a substantially high transmittance, e.g., above 95%) when the incident light has the first polarization, and partially reflect and partially transmit the incident light w hen the incident light has the second polarization that is perpendicular to the first polarization, e.g., with a 15% reflectance and 85% transmittance.
  • the real -world light 952-2 (represented by a dashed arrow ) may be an unpolarized light, and the polarizer 1150 may transmit the real-world light 952-2 as a real-world light 1156 having the first polarization toward the folding mirror 1140a.
  • the folding mirror 1140a may substantially transmit the real-world light 1158 having the first polarization as a real- world light 1158 propagating through the waveguide 1110.
  • the real-world light 1158 may not interact with the out-coupling minor 1145a.
  • the second rainbow effect caused by the w avelength-dependent reflection of the real- w orld light 952-2 at the folding mirror 1140a and the out-coupling mirror 1145a may be reduced.
  • the optical path of the real-world light 952-1 may be similar to that of the real-world light 952-2 and, thus, the first rainbow effect caused by the wavelength-dependent reflection of the real-world light 952-1 at the folding mirror 1140a may be reduced.
  • the in-coupled image light 1132 may be configured to have the second polarization.
  • the folding mirror 1140a may partially reflect and partially transmit the in-coupled image light 1132 having the second polarization. That is, the optical path of the in-coupled image light 1132 inside the waveguide 1110 may not be affected by the polarization selectivity of the folding mirror 1140a.
  • the in-coupled image light 1132 may be coupled out of the waveguide 1110 via the out-coupling mirrors 1145a as the output image lights 1134 prorogating toward the eye-box region 1159.
  • the out-coupling minor 1145a may also be configured to have the same polarization selectivity as the folding mirror 1140a.
  • the out-coupling minor 1145a may substantially transmit the real-world light 1162 having the first polarization toward the eye-box region 1159.
  • the rainbow effect perceived at the eye-box region 1159 may be further reduced.
  • the out-coupling mirror 1145a may partially reflect and partially transmit the in-coupled image light 1132 having the second polarization, thereby coupling the in-coupled image light 1132 out of the waveguide 1110 as the output image lights 1134 prorogating toward the eye-box region 1159.
  • the eye 1 160 located within the eye-box region 1 159 may perceive the virtual image superimposed with real-world image, with a reduced rainbow effect and an enhanced image quality.
  • the out-coupling mirror 1145a may also be configured to polarization non-selective.
  • the folding mirror 1140a may be configured to have both the angular selectivity shown in FIG. 1 IB and the polarization selectively shown in FIG. 1 IE.
  • FIG. 12A illustrates an x-y sectional view of a w aveguide display system 1200 configured to reduce a rainbow effect, according to an embodiment of the present disclosure.
  • the system 1200 may be implemented into an artificial reality device for AR and/or MR applications.
  • the system 1200 may be a geometric waveguide display system.
  • the system 1200 may include elements, structures, and/or functions that are the same as or similar to those included in the system 1100 shown in FIG. 11A. Detailed descriptions of the same or similar elements, structures, and/or functions may refer to the above descriptions rendered in connection with FIG. 11 A.
  • the system 1200 may include the light source assembly (not shown), the waveguide 1110, the in-coupling element 1135 embedded in the first portion 1111 of the waveguide 1110, a folding or redirecting element 1240 embedded in the second portion 1 112 of the waveguide 1110, and the out-coupling element 1145 embedded in the third portion 1113 of the waveguide 1110.
  • the folding element 1240 may include an array of folding mirrors 1240a
  • the out-coupling element 1145 may include the array of out- coupling mirrors 1145 a.
  • FIG. 12B illustrates a cross-sectional view of a portion of the waveguide 1110 along the first direction shown in FIG. 12A, showing an optical path of the real-world light 952-2 (represented by a dashed arrow), and an optical path of the in-coupled image light 1132 (represented by solid arrows) inside the waveguide 1110.
  • FIG. 12C illustrates a cross- sectional view of a portion of the waveguide 1110 along the second direction shown in FIG. 12A, showing an optical path of the in-coupled image light 1132 (represented by solid arrows) inside the waveguide 1110. As shown in FIGs.
  • the waveguide 1110 may have the first surface 1110-1 facing the eye-box region 1159 and the second surface 1110-2 opposite to the first surface 1110-1.
  • the system 1200 include an optical filter disposed at the second surface 1110-2 of the waveguide 1110, and may be in contact with the second surface 1110-2, or may be separated from the second surface 1110-2 by another film or a small gap.
  • a thickness direction of the waveguide 1110 e.g., a z-axis direction shown in FIGs.
  • the optical filter 1210 may at least partially overlap with the second portion 1112 of the waveguide 1110 where the array of folding mirrors 1240a are embedded, and may not overlap with the third portion 1 1 13 of the waveguide 1 1 10 where the array of out-coupling mirrors 1145a are disposed. In some embodiments, the optical filter 1210 may substantially overlap (e.g., 80%, 90%, 100%) with the second portion 1112 of the waveguide 1110 where the array of folding mirrors 1240a are embedded.
  • the optical filter 1210 may only interact with the real-world lights 952-1 and 952-2 that are incident onto the second portion 1112 of the waveguide 1110, and may not interact with the real-world light 952-3 that is incident onto the third portion 1113 of the waveguide 1110.
  • the optical filter 1210 may be an angularly selective filter, and the system 1200 may be configured to reduce the world side ghost (or rainbow) via configuring an angular selectivity of the optical filter 1210.
  • the first type of w orld side ghost has a vertical angular position ranging from about -90° to about -30° and a horizontal angular position ranging from about -70° to about -20°.
  • the second type of world side ghost has a vertical angular position ranging from about 80° to about 40° and a horizontal angular position ranging from about - 70° to about -40°.
  • the real-world light 952-1 (and the real-world light 952-2) may be diverted from propagating toward the eye-box region 1159. Accordingly, the first type of world side ghost (and the second type of world side ghost) may be reduced at the eye-box region 1159.
  • the optical filter 1210 when the AOI of the light at the optical filter 1210 is greater than or equal to a second predetermined angle (e.g., 40°. 50°, or 60°, etc.), the optical filter 1210 may be configured to substantially deflect (via diffraction) the incident light. When the AOI of the light at the optical filter 1210 is less than the second predetermined angle (e.g., 40°, 50°, or 60°, etc.), the optical filter 1210 may be configured to substantially transmit the incident light, with negligible diffraction.
  • a second predetermined angle e.g. 40°. 50°, or 60°, etc.
  • the optical filter 1210 may substantially reflect (via diffraction) the real-world light 952-1 as a real-world light 1256 back to the real world environment, thereby diverting the real-world light 952-1 from propagating toward the eye-box region 1159. Accordingly, the first type of world side ghost may be reduced at the eye-box region 1159. In some embodiments, the optical filter 1210 may also substantially reflect (via diffraction) the real-world light 952-2 back to the real world environment, thereby diverting the real-world light 952-2 from propagating toward the eye-box region 1159. Accordingly, the second type of world side ghost may be reduced at the eye-box region 1159.
  • the optical filter 1210 may include a suitable angularly selective filter.
  • the optical filter 1210 may include a photonic crystal.
  • the optical filter 1210 may include a volume Bragg grating (“VBG”) coating or film.
  • VBG volume Bragg grating
  • the optical filter 1210 may include a multiplexed VBG, in which a plurality of different grating periods may be recorded.
  • the multiplexed VBG may substantially reflect (via diffraction) different wavelength components of a visible polychromatic light (e.g., a white light).
  • the multiplexed VBG may be configured with three different grating periods corresponding to a red wavelength range, a green wavelength range, and a blue wavelength range, respectively.
  • the multiplexed VBG may substantially reflect (via diffraction) each of the red wavelength component, the green wavelength component, and the blue wavelength component back to the real world environment.
  • the optical filter 1210 may not attenuate the real-world light 952-3 incident onto the third portion 11 13 of the waveguide 1110 where the array of the out-coupling mirrors 1145a are located. That is, the real-world light 952-3 may propagate through the waveguide 1110, without being attenuated by the optical filter 1210.
  • the brightness of the see-through view observed through the third portion (or the output portion) 1113 of the waveguide 1 110 may not be degraded by the optical filter 1210.
  • the eye 1160 located within the eye-box region 1159 may perceive the virtual image superimposed with real-world image, with a reduced rainbow effect and an enhanced image quality.
  • FIG. 13 illustrates a schematic diagram of an artificial reality device 1300 configured to reduce a world side ghost (or rainbow), according to an embodiment of the present disclosure.
  • the artificial reality device 1300 may include a frame 1305 configured to mount to a user’s head.
  • the frame 1305 is merely an example structure to which various components of the artificial reality device 1300 may be mounted.
  • Other suitable type of fixtures may be used in place of or in combination with the frame 1305.
  • the frame 1305 may represent a frame of eyeglasses.
  • the artificial realitydevice 1300 may include a right-eye display system 1310R and a left-eye display system 1310L mounted to the frame 1305.
  • Each of the right-eye display system 131 OR and the lefteye display system 1310L may include a waveguide display system.
  • FIG. 13 merely shows the waveguide 1110, and the array of folding mirrors 1240a (1240), and the array of out-coupling mirrors 1145a (1145) embedded into the waveguide 1110.
  • the artificial reality device 1300 may also include a brim 1320 configured for each of the right-eye display system 1310R and a left-eye display system 1310L.
  • the brim 1320 may be mounted to the frame 1305, e.g., mounted to the horizontal piece of the frame 1305 that runs across the top of the lens.
  • the brim 1320 may be integrally formed as a part of the frame 1305.
  • the first type of world side ghost has a vertical angular position ranging from about -90° to about -30° (the negative vertical FOV directions correspond to angles above the horizontal plane of the eye 960).
  • the brim 1320 may be configured to absorb, reflect, and/or scatter the real-world light 952-1, thereby substantially blocking the real-world light 952-1 from being incident onto the folding mirrors 1240a.
  • the first type of world side ghost perceived at the eye-box region 1159 may be significantly reduced.
  • the waveguide display system 1100 shown in FIG. HA may also include the optical filter 1210 shown in FIGs. 12A and 12B.
  • the waveguide display system 1200 shown in FIG. 12A may also include the folding mirror 1140a having the angular selectivity shown in FIG. 1 IB and/or the polarization selectively shown in FIG. 1 IE.
  • an artificial reality device including the waveguide display system 1100 shown in FIG. 11A may also include the brim 1320 shown in FIG. 13.
  • an artificial reality' device including the waveguide display system 1200 shown in FIG. 12A may also include the brim 1320 shown in FIG. 13.
  • the couplers in the geometric waveguide display systems may include partially mirrors, beam splitters, or fully reflective mirrors, or a combination thereof, etc.
  • the mirrors in the geometric waveguide display systems may have suitable shapes, such as bar mirror arrays, pin-hole mirrors, etc.
  • the geometric waveguide display system may be a ID geometric w aveguide display system, a 2D geometric waveguide display system, or a Kaleido waveguide display system, etc.
  • the mechanisms and design principles disclosed herein for reducing the rainbow effect may also be applied to other types of waveguide which has the rainbow s (world side ghosts), such as a diffractive w aveguide with surface relief gratings, a diffractive waveguide with polarization volume holograms, a diffractive waveguide with volume Bragg gratings, or a mixed waveguide including both reflective coupler and diffractive couplers, etc.
  • FIG. 14A illustrates a schematic diagram of an artificial reality device 1400 according to an embodiment of the present disclosure.
  • the artificial reality device 1400 may produce VR, AR, and/or MR content for a user, such as images, video, audio, or a combination thereof.
  • the artificial reality device 1400 may be smart glasses.
  • the artificial reality device 1400 may be a near-eye display (“NED”).
  • the artificial reality device 1400 may be in the form of eyeglasses, goggles, a helmet, a visor, or some other type of eyew ear.
  • the artificial reality device 1400 may be configured to be worn on a head of a user (e.g., by having the form of spectacles or eyeglasses, as shown in FIG. 14A), or to be included as part of a helmet that is w'om by the user. In some embodiments, the artificial reality device 1400 may be configured for placement in proximity to an eye or eyes of the user at a fixed location in front of the eye(s), without being mounted to the head of the user. In some embodiments, the artificial reality device 1400 may be in a form of eyeglasses which provide vision correction to a user's eyesight. In some embodiments, the artificial reality device 1400 may be in a form of sunglasses which protect the eyes of the user from the bright sunlight.
  • the artificial reality device 1400 may be in a form of safety glasses which protect the eyes of the user. In some embodiments, the artificial reality device 1400 may be in a form of a night vision device or infrared goggles to enhance a user's vision at night.
  • FIG. 14A shows that the artificial reality device 1400 includes a frame 1405 configured to mount to a user’s head, and left-eye and right-eye display systems 1410L and 1410R mounted to the frame 1405.
  • the respective left-eye and right-eye display systems 1410L and 1410R include respective left and right display windows 1415L and 1415R.
  • FIG. 14B is a cross-sectional view of half of the artificial reality device 1400 shown in FIG. 14A according to an embodiment of the present disclosure.
  • FIG. 14B shows the cross-sectional view associated with the left-eye display system 1410L.
  • the frame 1405 is merely an example structure to which various components of the artificial reality device 1400 may be mounted. Other suitable type of fixtures may be used in place of or in combination with the frame 1405.
  • the left-eye and right-eye display systems 1410L and 1410R each may include suitable image display components 1425, 1418 configured to generate an image light representing a virtual image, and guide the image light toward the eye-box region 1159.
  • the left-eye and right-eye display systems 1410L and 141 OR each may include suitable optical components configured to direct the image light toward the eye-box region 1159.
  • FIG. 14B shows that the left-eye display systems 1410L may include a light source assembly (e.g., a projector) 1425 coupled to the frame 1405 and configured to generate the image light representing a virtual image.
  • a light source assembly e.g., a projector
  • the left-eye and right-eye display systems 1410L and 1410R each may include a waveguide display system disclosed herein, e.g., the system 1100 shown in FIGs. 11 A-l ID, the system 1100 shown in FIG. 11 A and FIGs. 1 IE and 1 IF, or the system 1200 show n in FIG. 12A-12C.
  • the user of the artificial reality device 1400 e.g., wearing the artificial reality device 1400, may perceive the virtual image superimposed with real-world image, with a reduced rainbow effect and an enhanced image quality.
  • the present disclosure provides a device.
  • the device includes a waveguide configured to guide an image light to propagate inside the waveguide via total internal reflection C’TIR"); an array of first mirrors embedded inside a first portion of the waveguide, and configured to split the image light into a plurality of redirected image lights propagating inside the waveguide; an array of second mirrors embedded inside a second portion of the waveguide, and configured to couple the redirected image lights out of the waveguide as a plurality of output image lights; and an optical filter disposed at a surface of the waveguide and at least partially overlapping with the first portion of the waveguide.
  • the optical filter is configured to deflect a light from a real-world environment incident onto the optical filter at an incidence angle greater than or equal to a predetermined angle back to the real-world environment.
  • the light from the real-world environment incident onto the optical filter at the incidence angle greater than or equal to the predetermined angle is a first light having a first incidence angle
  • the optical filter is configured to: transmit a second light from the real-world environment incident onto the optical filter at a second incidence angle less than the predetermined angle toward the first mirrors.
  • the optical filter does not overlap with the second portion of the waveguide.
  • the optical filter includes a volume Bragg grating.
  • the volume Bragg grating is a multiplexed volume Bragg grating having a plurality of different grating periods.
  • the optical filter includes a photonic crystal.
  • the present disclosure provides a device.
  • the device includes a waveguide configured to guide an image light to propagate inside the waveguide via total internal reflection (“TIR”); an array of folding mirrors embedded inside the waveguide, and configured to split the image light into a plurality of redirected image lights propagating inside the waveguide; and an array of out-coupling mirrors embedded inside the waveguide, and configured to couple the redirected image lights out of the waveguide as a plurality of output image lights.
  • TIR total internal reflection
  • Each folding mirror has a first surface facing the real-world environment and a second surface facing an eye-box region of the device, and the folding mirror is configured to substantially transmit a light from a real-world environment incident onto the second surface of the folding mirror at an incidence angle greater than or equal to a predetermined angle.
  • the folding mirror is configured to partially reflect the image light, which is incident onto the second surface of the folding mirror at the incidence angle less than the predetermined angle, toward the array of out-coupling mirrors.
  • the array of folding mirrors include a first folding mirror and a second folding mirror arranged in parallel, the first folding mirror is configured to couple a first light from the real-world environment incident on the first surface of the first folding mirror as a second light propagating inside the waveguide via TIR toward the second folding mirror, the second light being incident onto the second surface of the second folding mirror at the incidence angle greater than or equal to the predetermined angle, and the second folding mirror is configured to substantially transmit the second light out of the waveguide and toward the real-world environment.
  • the predetermined angle is in a range of 55° to 65°.
  • the present disclosure provides a device.
  • the device includes a waveguide configured to guide an image light to propagate inside the waveguide via total internal reflection; an array of folding mirrors embedded inside the waveguide, and configured to split the image light into a plurality of redirected image lights propagating inside the waveguide; and an array of out-coupling mirrors embedded inside the waveguide, and configured to couple the redirected image lights out of the waveguide as a plurality of output image lights.
  • the folding mirrors are configured to substantially transmit a light from a real-world environment having a first polarization, and partially reflect the image light having a second polarization orthogonal to the first polarization toward the array of out- coupling mirrors.
  • the folding mirrors are configured to reflect a first portion of the image light having the second polarization toward the array of out-coupling mirrors, and transmit a second portion of the image light.
  • the device further includes a polarizer disposed at a side of the waveguide facing the real-world environment, wherein the polarizer is configured to transmit an unpolarized light from the real-world environment as the light from the real-world environment having the first polarization toward the folding mirrors.
  • a software module is implemented with a computer program product including a computer-readable medium containing computer program code, which can be executed by a computer processor for performing any or all of the steps, operations, or processes described.
  • a hardware module may include hardware components such as a device, a system, an optical element, a controller, an electrical circuit, a logic gate, etc.
  • Embodiments of the present disclosure may also relate to an apparatus for performing the operations herein.
  • This apparatus may be specially constructed for the specific purposes, and/or it may include a general-purpose computing device selectively activated or reconfigured by a computer program stored in the computer.
  • a computer program may be stored in a non-transitory, tangible computer readable storage medium, or any type of media suitable for storing electronic instructions, which may be coupled to a computer system bus.
  • the non-transitory computer-readable storage medium can be any medium that can store program codes, for example, a magnetic disk, an optical disk, a readonly memory (‘‘ROM’'), or a random access memory (“RAM”), an Electrically Programmable read only memory (“EPROM”), an Electrically Erasable Programmable read only memory (“EEPROM”), a register, a hard disk, a solid-state disk drive, a smart media card (“SMC”), a secure digital card (“SD”), a flash card, etc.
  • any computing systems described in the specification may include a single processor or may be architectures employing multiple processors for increased computing capability.
  • the processor may be a central processing unit (“CPU”), a graphics processing unit (“GPU”), or any processing device configured to process data and/or performing computation based on data.
  • the processor may include both software and hardware components.
  • the processor may include a hardware component, such as an application-specific integrated circuit (“ASIC”), a programmable logic device (“PLD”). or a combination thereof.
  • ASIC application-specific integrated circuit
  • PLD programmable logic device
  • the PLD may be a complex programmable logic device (“CPLD”), a field-programmable gate array (“FPGA”), etc.
  • Embodiments of the present disclosure may also relate to a product that is produced by a computing process described herein.
  • a product may include information resulting from a computing process, where the information is stored on anon-transitory, tangible computer readable storage medium and may include any embodiment of a computer program product or other data combination described herein.
  • any optical device disclosed herein including one or more optical layers, films, plates, or elements including one or more optical layers, films, plates, or elements, the numbers of the layers, films, plates, or elements shown in the figures are for illustrative purposes only. In other embodiments not shown in the figures, which are still within the scope of the present disclosure, the same or different layers, films, plates, or elements shown in the same or different figures/embodiments may be combined or repeated in various manners to form a stack.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • General Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Human Computer Interaction (AREA)

Abstract

La présente invention propose un système. Le système comprend une source de lumière configurée pour émettre une lumière infrarouge (« IR ») afin d'éclairer un objet. Le système comprend également un ensemble d'imagerie de guide d'ondes contenant un guide d'ondes, un élément de couplage d'entrée disposé au niveau d'une première partie du guide d'ondes, un élément de couplage de sortie disposé au niveau d'une seconde partie du guide d'ondes, et un capteur optique disposé face à l'élément de couplage de sortie. L'élément de couplage d'entrée est configuré pour coupler la lumière IR réfléchie par l'objet dans le guide d'ondes, le guide d'ondes est configuré pour entraîner la lumière IR à se propager vers l'élément de couplage de sortie par réflexion interne totale, et l'élément de couplage de sortie est configuré pour coupler la lumière IR hors du guide d'ondes vers le capteur optique. Le capteur optique est configuré pour générer un signal de suivi de l'objet sur la base de la sortie de lumière IR provenant du guide d'ondes.
PCT/US2024/023681 2023-04-14 2024-04-09 Système d'imagerie basé sur un guide d'ondes pour suivi d'objet et système d'affichage basé sur un guide d'ondes pour réduire un fantôme côté monde Ceased WO2024215645A2 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US202363496381P 2023-04-14 2023-04-14
US63/496,381 2023-04-14
US202363500912P 2023-05-08 2023-05-08
US63/500,912 2023-05-08
US18/608,831 2024-03-18
US18/608,831 US12681298B2 (en) 2023-04-14 2024-03-18 Waveguide based imaging system for object tracking and waveguide based display system for reducing world side ghost

Publications (2)

Publication Number Publication Date
WO2024215645A2 true WO2024215645A2 (fr) 2024-10-17
WO2024215645A3 WO2024215645A3 (fr) 2024-11-21

Family

ID=91029861

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2024/023681 Ceased WO2024215645A2 (fr) 2023-04-14 2024-04-09 Système d'imagerie basé sur un guide d'ondes pour suivi d'objet et système d'affichage basé sur un guide d'ondes pour réduire un fantôme côté monde

Country Status (1)

Country Link
WO (1) WO2024215645A2 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120010043A (zh) * 2025-04-18 2025-05-16 东南大学 一种基于pvg技术的光栅波导装置及波导系统
CN121477486A (zh) * 2025-11-18 2026-02-06 北京环境特性研究所 一种波导光路复用的眼动追踪系统及其使用方法
WO2026082161A1 (fr) * 2024-10-17 2026-04-23 烟台睿创微纳技术股份有限公司 Caméra à guide d'ondes optique et système optique

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3942227A4 (fr) * 2019-03-20 2022-12-07 Magic Leap, Inc. Système de collecte de lumière
US12387343B2 (en) * 2020-10-07 2025-08-12 Samsung Electronics Co., Ltd. Eye position tracking sensor and method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2026082161A1 (fr) * 2024-10-17 2026-04-23 烟台睿创微纳技术股份有限公司 Caméra à guide d'ondes optique et système optique
CN120010043A (zh) * 2025-04-18 2025-05-16 东南大学 一种基于pvg技术的光栅波导装置及波导系统
CN121477486A (zh) * 2025-11-18 2026-02-06 北京环境特性研究所 一种波导光路复用的眼动追踪系统及其使用方法

Also Published As

Publication number Publication date
WO2024215645A3 (fr) 2024-11-21

Similar Documents

Publication Publication Date Title
US8848289B2 (en) Near-to-eye display with diffractive lens
EP2740004B1 (fr) Procédé et appareil permettant un affichage proche de l' il
US11869560B2 (en) Object tracking system including polarization selective optical element
US9389422B1 (en) Eyepiece for head wearable display using partial and total internal reflections
US12399369B2 (en) Curved light guide image combiner and system including the same
US11852827B2 (en) Switchable artificial reality device
US11635624B1 (en) Light guide display assembly for providing increased pupil replication density
US11733445B2 (en) Optical element having multiple layers for reducing diffraction artifacts
WO2022130372A1 (fr) Méthodes et systèmes d'oculométrie sur la base de l'imagerie de l'œil par le biais d'un élément de collimation et d'un élément guide de lumière
US12436394B2 (en) Augmented reality (or mixed reality) eyewear with see-through optical elements having individually-adjustable opacity/reflectivity levels
EP4479679A1 (fr) Guide d'ondes hybride pour maximiser la couverture dans le champ de vision (fov)
US20240242450A1 (en) Holovisions(TM) -- Adjustable and/or Modular Augmented Reality (AR) Eyewear with a Movable Transflective Mirror and Different Viewing Modes
EP4261597B1 (fr) Dispositif d'affichage fovéal proche de l'oeil avec résolution rétinienne et grand champ de vision
US12001017B1 (en) Illumination system for object tracking
US20240345389A1 (en) Waveguide based imaging system for object tracking and waveguide based display system for reducing world side ghost
US20230080580A1 (en) Liquid crystal polarization hologram element for reducing rainbow effects
EP4374213B1 (fr) Lentilles holographiques à polarisation accordable
US20230359041A1 (en) Light guide display system including freeform volume grating
US11796881B2 (en) Blue phase liquid crystal polarization hologram comprising liquid crystal molecules having a spatially varying in-plane orientation pattern and device including the same
CN118786376A (zh) 调节集成式折光透镜组件
US20230305490A1 (en) Accommodation integrated folding lens assembly
EP4500262B1 (fr) Ensemble lentille pliable intégré de réception
US20220128756A1 (en) Display system for generating three-dimensional image and method therefor
US20250060588A1 (en) Display system for providing high contrast ratio and reducing rainbow effect
US20240337785A1 (en) Switchable structured illumination generator, light guide display system with stray light reduction, and stress-neutral optical coating

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24724726

Country of ref document: EP

Kind code of ref document: A2

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 24724726

Country of ref document: EP

Kind code of ref document: A2