TWI851255B - Display apparatus - Google Patents

Abstract

A display apparatus including a display panel, a polarization modulator, a first liquid crystal lens and a second liquid crystal lens is provided. The polarization modulator is disposed on one side of the display panel. A first light beam and a second light beam coming from the display panel respectively have a first polarization state and a second polarization state after passing through the enabled polarization modulator. The first liquid crystal lens and the second liquid crystal lens are disposed on one side of the polarization modulator away from the display panel. The first liquid crystal lens is located between the polarization modulator and the second liquid crystal lens. The enabled first liquid crystal lens has a first maximum phase retardation for the first light beam having the first polarization state. The enabled second liquid crystal lens has a second maximum phase retardation for the second light beam having the second polarization state. The first maximum phase retardation is less than the second maximum phase retardation.

Description

Display device

The present invention relates to a display device, and in particular to a display device provided with a liquid crystal lens.

In traditional head-mounted displays, if you want to adjust the focusing depth of the human eye, most of the adjustments are made by using microlens arrays, curved mirror groups, etc. in combination with adjustable focus optical elements. However, such an architecture is not conducive to the lightweight of the head-mounted display. Another architecture for achieving a stereoscopic display effect is to use a semi-reflective and semi-transparent film, a quarter-wave plate, a polarized reflective layer, etc. to present images of different focal lengths. However, in this type of technology, light will cause loss of light energy due to multiple reflections, resulting in a decrease in display brightness. In addition, although the time-sharing display of images of different focal lengths (or depths of field) can achieve the effect of stereoscopic display, the design of the driving circuit is relatively complex.

The present invention provides a display device which has a better three-dimensional display effect and can effectively avoid discomfort when viewing three-dimensional images.

The display device of the present invention includes a display panel, a polarization modulator, a first liquid crystal lens and a second liquid crystal lens. The display panel has a display surface and is suitable for emitting a first light beam and a second light beam. The polarization modulator is arranged on one side of the display surface of the display panel and overlaps the display surface. The polarization modulator is provided with a first modulation area and a second modulation area. When the polarization modulator is enabled, the first light beam has a first polarization state after passing through the first modulation area. The polarization state of the second light beam has a second polarization state after passing through the second modulation area. The first polarization state is orthogonal to the second polarization state. The first liquid crystal lens and the second liquid crystal lens are arranged on a side of the polarization modulator away from the display panel. The first liquid crystal lens is located between the polarization modulator and the second liquid crystal lens. When the first liquid crystal lens and the second liquid crystal lens are enabled, the first liquid crystal lens has a first maximum phase delay for a first light beam with a first polarization state, and the second liquid crystal lens has a second maximum phase delay for a second light beam with a second polarization state, and the first maximum phase delay is smaller than the second maximum phase delay.

In a display device of an embodiment of the present invention, when the first liquid crystal lens and the second liquid crystal lens are enabled, the phase delay of the first liquid crystal lens to the second light beam with the second polarization state is zero, and the phase delay of the second liquid crystal lens to the first light beam with the first polarization state is zero.

In a display device of an embodiment of the present invention, when the first liquid crystal lens and the second liquid crystal lens are enabled, the first liquid crystal lens has a first focal length for a first light beam having a first polarization state, and the second liquid crystal lens has a second focal length for a second light beam having a second polarization state, and the first focal length is different from the second focal length.

In an embodiment of the present invention, the polarization modulator of the display device is provided with a plurality of first modulation areas and a plurality of second modulation areas. The first modulation areas and the second modulation areas are alternately arranged along a first direction or a second direction. The first direction is perpendicular to the second direction.

In one embodiment of the present invention, the polarization modulator of the display device includes a plurality of liquid crystal molecules and a plurality of dye molecules. The dye molecules are dispersedly disposed between the liquid crystal molecules and include a first portion and a second portion. The first portion and the second portion are located in a first modulation zone and a second modulation zone, respectively. When the polarization modulator is enabled, the polarization direction of the first polarization state is perpendicular to the axial direction of the absorption axis of the first portion, and the polarization direction of the second polarization state is perpendicular to the axial direction of the absorption axis of the second portion.

In one embodiment of the present invention, the first liquid crystal lens of the above-mentioned display device includes a first alignment film, a second alignment film, and a first liquid crystal layer sandwiched between the first alignment film and the second alignment film. The alignment directions of the first alignment film and the second alignment film are respectively parallel to the polarization direction of the first light beam after passing through the polarization modulator. The second liquid crystal lens includes a third alignment film, a fourth alignment film, and a second liquid crystal layer sandwiched between the third alignment film and the fourth alignment film. The alignment directions of the third alignment film and the fourth alignment film are respectively parallel to the polarization direction of the second light beam after passing through the polarization modulator.

In one embodiment of the present invention, the thickness and material of the first liquid crystal layer and the second liquid crystal layer of the display device are the same. When the first liquid crystal lens and the second liquid crystal lens are enabled, the first liquid crystal layer is applied with a first voltage and has a first maximum phase retardation, and the second liquid crystal layer is applied with a second voltage and has a second maximum phase retardation, and the first voltage is different from the second voltage.

In one embodiment of the present invention, the first liquid crystal lens of the display device further includes a first substrate and two electrodes disposed on the first substrate. The two electrodes of the first liquid crystal lens are arranged along the alignment directions of the first alignment film and the second alignment film. The second liquid crystal lens further includes a second substrate and two electrodes disposed on the second substrate. The two electrodes of the second liquid crystal lens are arranged along the alignment directions of the third alignment film and the fourth alignment film.

In one embodiment of the present invention, the first liquid crystal lens of the display device has a first optical axis, and the second liquid crystal lens has a second optical axis. When the first liquid crystal lens and the second liquid crystal lens are enabled, the phase delay of the first liquid crystal lens gradually decreases as it moves away from the first optical axis, and the phase delay of the second liquid crystal lens gradually decreases as it moves away from the second optical axis.

In one embodiment of the present invention, the first light beam and the second light beam emitted by the display panel of the display device each have a second polarization state. When the polarization modulator is enabled, the polarization state of the first light beam changes from the second polarization state to the first polarization state after passing through the first modulation zone, and the polarization state of the second light beam remains in the second polarization state after passing through the second modulation zone.

In an embodiment of the present invention, the display device further comprises a polarizer disposed between the display panel and the polarization modulator. The first light beam and the second light beam from the display panel each have a second polarization state after passing through the polarizer.

Based on the above, in a display device of an embodiment of the present invention, when the first liquid crystal lens and the second liquid crystal lens are enabled, the maximum phase delay of the first liquid crystal lens to the first light beam having the first polarization state is different from the maximum phase delay of the second liquid crystal lens to the second light beam having the second polarization state. Accordingly, the first light beam and the second light beam having different polarization states can be focused at different positions after passing through the first liquid crystal lens and the second liquid crystal lens, and then present corresponding display images at different depths of field, so that the user can have a three-dimensional image visual experience when watching.

The above-mentioned other technical contents, features and effects of the present invention will be clearly presented in the detailed description of the preferred embodiment with reference to the following drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only referenced to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and are not used to limit the present invention.

FIG1 is a schematic cross-sectional view of a display device according to a first embodiment of the present invention. FIG2 is a schematic front view of a polarization modulator of FIG1. FIG3 is a schematic diagram of polarization state distribution of multiple first light beams and multiple second light beams of FIG1 after passing through the polarization modulator of FIG2. FIG4A is a partially enlarged schematic diagram of the polarization modulator of FIG1 when it is not enabled. FIG4B is a partially enlarged schematic diagram of the polarization modulator of FIG1 when it is enabled. FIG5A and FIG5B are respectively partially enlarged schematic diagrams of the first liquid crystal lens and the second liquid crystal lens of FIG1 when they are not enabled. FIG6A is a schematic front view of the first liquid crystal lens of FIG5A. FIG6B is a schematic front view of the second liquid crystal lens of FIG5B. FIG7A and FIG7B are respectively partially enlarged schematic diagrams of the first liquid crystal lens and the second liquid crystal lens of FIG1 when they are enabled.

1 , the display device 10 includes a display panel 100, a polarization modulator 130, a first liquid crystal lens 151, and a second liquid crystal lens 152. The display panel 100 has a display surface DS. The polarization modulator 130 is disposed on one side of the display surface DS of the display panel 100 and overlaps the display surface DS along a direction Y. The first liquid crystal lens 151 and the second liquid crystal lens 152 are disposed on a side of the polarization modulator 130 away from the display panel 100, and the first liquid crystal lens 151 is located between the polarization modulator 130 and the second liquid crystal lens 152.

In the present embodiment, the display panel 100 is, for example, an organic light emitting diode (OLED) display panel, a micro light emitting diode (micro-LED) display panel, a sub-millimeter light emitting diode (mini-LED) display panel, or other suitable self-luminous display panels. Therefore, the first light beam LB1 and the second light beam LB2 emitted by the display panel 100 may be non-polarized light (i.e., light beams without a specific polarization state).

The polarization modulator 130 may be provided with a plurality of first modulation areas MA1 and a plurality of second modulation areas MA2. For example, in the present embodiment, the first modulation areas MA1 and the second modulation areas MA2 may be arranged alternately along the direction X or the direction Z (as shown in FIG. 2 ). The display panel 100 is adapted to emit a plurality of first light beams LB1 toward the plurality of first modulation areas MA1 of the polarization modulator 130, and emit a plurality of second light beams LB2 toward the plurality of second modulation areas MA2.

The first light beam LB1 has a first polarization state P1 after passing through the first modulation area MA1. The second light beam LB2 has a second polarization state P2 after passing through the second modulation area MA2. The first polarization state P1 is orthogonal to the second polarization state P2. For example, in this embodiment, the first polarization state P1 is a linear polarization state with a polarization direction parallel to the direction Z, and the second polarization state P2 is a linear polarization state with a polarization direction parallel to the direction X.

Please refer to FIG. 2 to FIG. 4B . In this embodiment, the polarization modulator 130 may include a substrate 131, a substrate 132, a plurality of liquid crystal molecules LCM, and a plurality of dye molecules DM. The liquid crystal layer composed of the plurality of liquid crystal molecules LCM is sandwiched between the substrate 131 and the substrate 132, and the plurality of dye molecules DM are dispersedly arranged between these liquid crystal molecules LCM. In particular, the molecular long axis (i.e., the absorption axis) of the dye molecule DM tends to be arranged along the molecular long axis of the liquid crystal molecule LCM. Therefore, the axial direction of the molecular long axis of the dye molecule DM can be adjusted by the arrangement and distribution of the liquid crystal molecule LCM under different electric fields.

In the present embodiment, a plurality of electrodes E1 and a plurality of electrodes E2 may be disposed on the substrate 131 of the polarization modulator 130. Each modulation region is provided with at least one electrode E1 and one electrode E2, and an electric field for driving the liquid crystal molecules LCM to rotate may be formed between the electrodes E1 and E2. For example, when the electrodes are disabled (i.e., when the polarization modulator 130 is not enabled), the plurality of liquid crystal molecules LCM and the plurality of dye molecules DM are generally arranged along the direction X. Therefore, after the first light beam LB1 and the second light beam LB2 from the display panel 100 pass through the polarization modulator 130, the electric field component whose polarization direction is parallel to the absorption axis of the dye molecule DM will be absorbed by the dye molecule DM, while the electric field component whose polarization direction is perpendicular to the absorption axis of the dye molecule DM can pass through the polarization modulator 130. That is, the unpolarized light from the display panel 100 will become polarized light having the first polarization state P1 after passing through the non-enabled polarization modulator 130 (as shown in FIG. 4A ).

The plurality of dye molecules DM may include a first portion DM1 located in the first modulation area MA1 and a second portion DM2 located in the second modulation area MA2. When the polarization modulator 130 is enabled, an electric field EF substantially parallel to the direction Z is formed between the electrode E1 and the electrode E2 located in the second modulation area MA2. Driven by the electric field EF, the long axis of the liquid crystal molecules LCM located in the second modulation area MA2 tends to be arranged along the direction Z. It is particularly noted that at this time, the electrode E1 and the electrode E2 in the first modulation area MA1 are not enabled, and the long axis of the liquid crystal molecules LCM located in the first modulation area MA1 is still parallel to the direction X.

Since the molecular long axis (or absorption axis) of the dye molecules DM tends to be arranged along the molecular long axis of the liquid crystal molecules LCM, when the polarization modulator 130 is enabled in the above manner, the axial direction of the absorption axis AX1 of the first portion DM1 of the plurality of dye molecules DM in the first modulation area MA1 is substantially parallel to the direction X, and the axial direction of the absorption axis AX2 of the second portion DM2 in the second modulation area MA2 is substantially parallel to the direction Z. That is, the axial direction of the absorption axis AX1 of the first portion DM1 is perpendicular to the axial direction of the absorption axis AX2 of the second portion DM2 (as shown in FIG. 2 ).

Based on the above arrangement, after the non-polarized light from the display panel 100 passes through the enabled polarization modulator 130, the portion passing through the first modulation area MA1 forms a first light beam LB1 having a first polarization state P1, and the other portion passing through the second modulation area MA2 forms a second light beam LB2 having a second polarization state P2. The polarization direction of the first polarization state P1 is perpendicular to the axial direction of the absorption axis AX1 of the first portion DM1, and the polarization direction of the second polarization state P2 is perpendicular to the axial direction of the absorption axis AX2 of the second portion DM2 (as shown in FIG. 2 and FIG. 3).

1, 5A and 5B, in this embodiment, the first liquid crystal lens 151 may include a substrate 151S1, a substrate 151S2, a first liquid crystal layer LCL1, a first alignment film AL1, a second alignment film AL2, two electrodes 151E1 and an electrode 151E2. The first liquid crystal layer LCL1 is disposed between the substrate 151S1 and the substrate 151S2, and includes a plurality of first liquid crystal molecules LCM1. The two electrodes 151E1 are disposed on the substrate 151S1 (i.e., the first substrate) and are covered by the first alignment film AL1. The electrode 151E2 is disposed on the substrate 151S2 and is covered by the second alignment film AL2. The first liquid crystal layer LCL1 is sandwiched between the first alignment film AL1 and the second alignment film AL2.

Similarly, the second liquid crystal lens 152 may include a substrate 152S1, a substrate 152S2, a second liquid crystal layer LCL2, a third alignment film AL3, a fourth alignment film AL4, two electrodes 152E1, and an electrode 152E2. The second liquid crystal layer LCL2 is disposed between the substrate 152S1 and the substrate 152S2, and includes a plurality of second liquid crystal molecules LCM2. The two electrodes 152E1 are disposed on the substrate 152S1 (i.e., the second substrate) and are covered by the third alignment film AL3. The electrode 152E2 is disposed on the substrate 152S2 and is covered by the fourth alignment film AL4.

In this embodiment, the structures and design parameters of the first liquid crystal lens 151 and the second liquid crystal lens 152 can be selectively the same, for example, the materials of the first liquid crystal layer LCL1 and the second liquid crystal layer LCL2 can be the same, and the thickness d1 of the first liquid crystal layer LCL1 and the thickness d2 of the second liquid crystal layer LCL2 are also the same, but not limited thereto. In addition, the patterned designs of the electrode 151E1 and the electrode 152E1 (or the electrode 151E2 and the electrode 152E2) can also be the same. More specifically, in this embodiment, the first liquid crystal lens 151 and the second liquid crystal lens 152 can be made of a liquid crystal box of the same design specification, but not limited thereto.

1 and 5A to 6B, the alignment direction AD1 of the first alignment film AL1 of the first liquid crystal lens 151 and the alignment direction AD2 of the second alignment film AL2 are parallel to the direction Z, and the alignment direction AD1 is antiparallel to the alignment direction AD2. The alignment direction AD3 of the third alignment film AL3 of the second liquid crystal lens 152 and the alignment direction AD4 of the fourth alignment film AL4 are parallel to the direction X, and the alignment direction AD3 is antiparallel to the alignment direction AD4.

That is, no matter whether the first liquid crystal lens 151 is enabled or not, the molecular long axis of the first liquid crystal molecule LCM1 will generally rotate or arrange along the YZ plane; similarly, no matter whether the second liquid crystal lens 152 is enabled or not, the molecular long axis of the second liquid crystal molecule LCM2 will generally rotate or arrange along the XY plane. That is, in the viewing direction (e.g., direction Y) of the display device 10, the long axis direction of the first liquid crystal molecule LCM1 is generally orthogonal to the long axis direction of the second liquid crystal molecule LCM2 (as shown in FIG. 6A and FIG. 6B ).

It should be noted that in the present embodiment, the alignment direction AD1 of the first alignment film AL1 and the alignment direction AD2 of the second alignment film AL2 of the first liquid crystal lens 151 are parallel to the polarization direction of the first light beam LB1 after passing through the polarization modulator 130 (i.e., the polarization direction of the first polarization state P1). The alignment direction AD3 of the third alignment film AL3 and the alignment direction AD4 of the fourth alignment film AL4 of the second liquid crystal lens 152 are parallel to the polarization direction of the second light beam LB2 after passing through the polarization modulator 130 (i.e., the polarization direction of the second polarization state P2). From another point of view, the two electrodes 151E1 provided on the substrate 151S1 of the first liquid crystal lens 151 are arranged along the alignment direction AD1 of the first alignment film AL1 and the alignment direction AD2 of the second alignment film AL2, and the two electrodes 152E1 on the substrate 152S1 of the second liquid crystal lens 152 are arranged along the alignment direction AD3 of the third alignment film AL3 and the alignment direction AD4 of the fourth alignment film AL4.

In this embodiment, the first liquid crystal molecules LCM1 and the second liquid crystal molecules LCM2 are, for example, positive liquid crystal molecules, and these liquid crystal molecules are arranged horizontally between the two substrates along the alignment direction of the alignment film when no electric field is applied, but the present invention is not limited thereto. In other embodiments not shown, the liquid crystal layer of the liquid crystal lens may also be negative liquid crystal, and the initial arrangement direction of the liquid crystal molecules (i.e., when no electric field is applied) is perpendicular to the polarization direction of the incident light beam; when an electric field is applied, the long axis direction of the liquid crystal molecules rotates in a direction not perpendicular to the polarization direction of the incident light beam.

Since the thickness and material of the first liquid crystal layer LCL1 and the second liquid crystal layer LCL2 of this embodiment are selectively the same, when the first liquid crystal lens 151 and the second liquid crystal lens 152 are not enabled, the first liquid crystal layer LCL1 and the second liquid crystal layer LCL2 may have the same maximum phase delay PR0 (as shown in FIGS. 5A and 5B ).

From another point of view, the first liquid crystal lens 151 and the second liquid crystal lens 152 have a first optical axis OA1 and a second optical axis OA2, respectively. When the first liquid crystal lens 151 is not enabled, the phase retardation of the first liquid crystal layer LCL1 remains unchanged as it moves away from the first optical axis OA1, that is, the phase retardation of the first liquid crystal layer LCL1 at different positions in the direction Z is generally maintained at the maximum phase retardation PR0. Similarly, when the second liquid crystal lens 152 is not enabled, the phase retardation of the second liquid crystal layer LCL2 remains unchanged as it moves away from the second optical axis OA2, that is, the phase retardation of the second liquid crystal layer LCL2 at different positions in the direction X is generally maintained at the maximum phase retardation PR0.

Please refer to Figures 1, 7A and 7B, when the first liquid crystal lens 151 and the second liquid crystal lens 152 are enabled, the first liquid crystal lens 151 has a first maximum phase delay PR1 for the first light beam LB1 with the first polarization state P1, and the second liquid crystal lens 152 has a second maximum phase delay PR2 for the second light beam LB2 with the second polarization state P2, and the first maximum phase delay PR1 is less than the second maximum phase delay PR2.

In detail, the enabled first liquid crystal lens 151 has a plurality of first liquid crystal molecules LCM1 that form different arrangement directions at different positions in the direction Z due to different applied electric field strengths. For example, the first liquid crystal molecules LCM1 closer to the first optical axis OA1 are less deflected due to the weaker applied electric field strength, and the first liquid crystal molecules LCM1 farther from the first optical axis OA1 are more deflected due to the stronger applied electric field strength, resulting in the first light beam LB1 propagating along the light beam traveling direction (e.g., direction Y) and having the first polarization state P1. The average refractive index felt at different positions in the direction Z will gradually decrease as it moves away from the first optical axis OA1. Therefore, the phase retardation amount of the first liquid crystal layer LCL1 gradually decreases from the maximum phase retardation amount PR1 as it moves away from the first optical axis OA1.

On the other hand, the enabled second liquid crystal lens 152 has a plurality of second liquid crystal molecules LCM2 that form different arrangement directions at different positions in the direction X due to different applied electric field strengths. For example, the second liquid crystal molecules LCM2 closer to the second optical axis OA2 are less deflected due to the weaker applied electric field strength, and the second liquid crystal molecules LCM2 farther from the second optical axis OA2 are more deflected due to the stronger applied electric field strength, causing the second light beam LB2 propagating along the direction of the light beam and having the second polarization state P2 to experience an average refractive index at different positions in the direction X that decreases as it moves away from the second optical axis OA2. Therefore, the phase delay of the second liquid crystal layer LCL2 decreases from the maximum phase delay PR2 as it moves away from the second optical axis OA2.

It should be noted that the first liquid crystal layer LCL1 is applied with a first voltage V1 and has the aforementioned first maximum phase retardation PR1, and the second liquid crystal layer LCL2 is applied with a second voltage V2 and has the aforementioned second maximum phase retardation PR2, wherein the first voltage V1 is different from the second voltage V2. In this embodiment, the first voltage V1 may be selectively greater than the second voltage V2. Therefore, the first maximum phase retardation PR1 of the first liquid crystal layer LCL1 is less than the second maximum phase retardation PR2 of the second liquid crystal layer LCL2, and both the first maximum phase retardation PR1 and the second maximum phase retardation PR2 are less than the maximum phase retardation PR0 when no electric field is applied to the first liquid crystal layer LCL1 and the second liquid crystal layer LCL2. More specifically, the maximum phase retardation of the liquid crystal layer will decrease as the applied voltage increases.

Since the phase delay of the first light beam LB1 passing through is different at different positions of the enabled first liquid crystal lens 151 in the direction Z, the multiple first light beams LB1 will have optical path differences due to different passing positions after passing through the enabled first liquid crystal lens 151, so that these first light beams LB1 will produce a focusing or astigmatism effect after passing through the first liquid crystal lens 151. In this embodiment, since the phase delay of the first liquid crystal layer LCL1 to the first light beam LB1 decreases as it moves away from the first optical axis OA1, the enabled first liquid crystal lens 151 will produce a focusing effect on the first light beam LB1 (as shown in FIG. 1), and has a first focal length f1. Similarly, since the phase delay of the second liquid crystal layer LCL2 to the second light beam LB2 decreases with the distance from the second optical axis OA2, the enabled second liquid crystal lens 152 produces a focusing effect on the second light beam LB2 (as shown in FIG. 1 ) and has a second focal length f2. The first focal length f1 is different from the second focal length f2.

In this embodiment, the user USR can view the display image of the display device 10 along the direction Y from the side of the second liquid crystal lens 152 away from the first liquid crystal lens 151. In other words, the second liquid crystal lens 152 of this embodiment is closer to the user USR, so the second focal length f2 of the enabled second liquid crystal lens 152 can be smaller than the first focal length f1 of the enabled first liquid crystal lens 151, but not limited thereto. In particular, the focal length f of the liquid crystal lens can satisfy the following relationship: , where r is the radius of the liquid crystal lens, is the difference between the maximum refractive index and the minimum refractive index of the liquid crystal layer, and d is the thickness of the liquid crystal layer (for example, thickness d1 and thickness d2).

Since the first liquid crystal lens 151 and the second liquid crystal lens 152 of this embodiment have the same structural dimensions and liquid crystal materials, the focal lengths of the two liquid crystal lenses depend on the difference between the maximum effective refractive index and the minimum refractive index of the liquid crystal layer when the first voltage V1 and the second voltage V2 are applied, respectively. That is, in this embodiment, the focal length of the liquid crystal lens is adjusted by different applied voltages. However, the present invention is not limited thereto. In other embodiments, the focal lengths of the first liquid crystal lens and the second liquid crystal lens can also be adjusted by different liquid crystal layer thicknesses or different liquid crystal layer materials.

In this embodiment, the display panel 100 can synchronously display images of different depths of field, and through the different focusing capabilities of the first liquid crystal lens 151 and the second liquid crystal lens 152, the image beams of different depths of field (such as the first light beam LB1 and the second light beam LB2) can be focused on the eyes of the user USR, so that the user USR can synchronously see the images of different depths of field and produce a three-dimensional image visual experience. In addition to avoiding the complex circuit design of the existing three-dimensional display technology for displaying images of different depths in a time-sharing manner, it also helps to reduce the weight of the display device.

It is particularly noted that, since the polarization direction (e.g., direction Z) of the first light beam LB1 is perpendicular to the molecular long axis of the second liquid crystal molecule LCM2, and the polarization direction (e.g., direction X) of the second light beam LB2 is perpendicular to the molecular long axis of the first liquid crystal molecule LCM1, the phase delay of the enabled first liquid crystal lens 151 to the second light beam LB2 having the second polarization state P2 is substantially zero, and the phase delay of the enabled second liquid crystal lens 152 to the first light beam LB1 having the first polarization state P1 is substantially zero. In other words, the enabled first liquid crystal lens 151 does not have a substantial refraction (or focusing) effect on the second light beam LB2 having the second polarization state P2, and the enabled second liquid crystal lens 152 does not have a substantial refraction (or focusing) effect on the first light beam LB1 having the first polarization state P1.

Other embodiments are listed below to illustrate the present disclosure in detail, wherein the same components are marked with the same symbols, and the description of the same technical content is omitted. For the omitted parts, please refer to the aforementioned embodiments, which will not be described in detail below.

FIG8 is a schematic cross-sectional view of a display device according to a second embodiment of the present invention. FIG9A is a partially enlarged schematic view of the polarization modulator of FIG8 when it is not enabled. FIG9B is a partially enlarged schematic view of the polarization modulator of FIG8 when it is enabled. FIG10A is a schematic cross-sectional view of another embodiment of the polarization modulator of FIG8 when it is not enabled. FIG10B is a schematic cross-sectional view of another embodiment of the polarization modulator of FIG8 when it is enabled.

8 , unlike the self-luminous display panel 100 in FIG. 1 , in this embodiment, the display panel 100A of the display device 10A may be a liquid crystal display panel and is adapted to emit a first light beam LB1 and a second light beam LB2 having a second polarization state P2 .

It is particularly noted that when the polarization modulator 130A is enabled, the polarization state of the first light beam LB1 having the second polarization state P2 is changed from the second polarization state P2 to the first polarization state P1 after passing through the first modulation zone MA1 of the polarization modulator 130A. The polarization state of the second light beam LB2 having the second polarization state P2 is maintained at the second polarization state P2 after passing through the second modulation zone MA2 of the polarization modulator 130A.

For example, in this embodiment, the polarization modulator 130A is a twisted nematic (TN) liquid crystal cell and may include a substrate 131, a substrate 132, a liquid crystal layer LCL-A, a plurality of electrodes E1-A, and a plurality of electrodes E2-A. The electrode E1-A and the electrode E2-A are disposed on the substrate 131 and the substrate 132, respectively. The liquid crystal layer LCL-A is disposed between the electrode E1-A and the electrode E2-A. In this embodiment, at least one electrode E1-A and one electrode E2-A are disposed overlapping each other in each modulation region.

It should be understood that two alignment films (not shown) are respectively disposed on the substrate 131 and the substrate 132, and the alignment directions of the two alignment films are orthogonal to each other. For example, the alignment direction of the alignment film on the substrate 131 may be parallel to the direction X, and the alignment direction of the alignment film on the substrate 132 may be parallel to the direction Z. Therefore, when the polarization modulator 130A is not enabled, the molecular long axes of the plurality of liquid crystal molecules LCM-A of the liquid crystal layer LCL-A will present a 90-degree twisted arrangement from the substrate 131 to the substrate 132.

When the first light beam LB1 or the second light beam LB2 having the second polarization state P2 passes through the unenabled polarization modulator 130A, the second polarization state P2 is converted into the first polarization state P1. In the present embodiment, when the polarization modulator 130A is enabled, the electrodes E1-A and E2-A in the first modulation area MA1 are disabled, and only the electrodes E1-A and E2-A in the second modulation area MA2 are enabled.

The electric field formed between the enabled electrode E1-A and the electrode E2-A drives the molecular long axis of the liquid crystal molecules LCM-A in the second modulation area MA2 to be arranged perpendicular to the substrate 131, so that the portion of the liquid crystal layer LCL-A located in the second modulation area MA2 will not produce a substantial phase delay for the passing second light beam LB2. Therefore, after the second light beam LB2 passes through the enabled second modulation area MA2, its polarization state remains in the second polarization state P2.

That is, in this embodiment, after passing through the enabled polarization modulator 130A, the plurality of first light beams LB1 and the plurality of second light beams LB2 can also form a polarization state distribution as shown in FIG3. Since the first liquid crystal lens 151 and the second liquid crystal lens 152 of this embodiment and their effects on the light beams are similar to the first liquid crystal lens 151 and the second liquid crystal lens 152 of FIG1 , please refer to the relevant paragraphs of the aforementioned embodiment for detailed description, which will not be repeated here.

However, the present invention is not limited thereto. Referring to FIG. 10A and FIG. 10B , in another variant embodiment, the polarization modulator 130B may also be an electrically controlled birefringence (ECB) liquid crystal cell. Unlike the liquid crystal molecules LCM-A in FIG. 9A , which are twisted in arrangement without an external field, the plurality of liquid crystal molecules LCM-B in FIG. 10A are arranged in an anti-parallel state without an external field. More specifically, in the polarization modulator 130B of FIG10A , the angle between the orthographic projection of the molecular long axis of the liquid crystal molecule LCM-B on the substrate 131 and the direction X or direction Z without the action of an electric field is 45 degrees, and at this time the liquid crystal layer LCL-B will produce a substantial phase delay for the passing first light beam LB1 or second light beam LB2, causing its polarization state to change from the second polarization state P2 to the first polarization state P1 (as shown in FIG10A ).

When the polarization modulator 130B is enabled, the electrodes E1-A and E2-A in the first modulation area MA1 are disabled, and only the electrodes E1-A and E2-A in the second modulation area MA2 are enabled. The electric field formed between the enabled electrodes E1-A and E2-A drives the molecular long axis of the liquid crystal molecules LCM-B in the second modulation area MA2 to be arranged perpendicular to the substrate 131, so that the portion of the liquid crystal layer LCL-B in the second modulation area MA2 will not produce a substantial phase delay for the passing second light beam LB2. Therefore, after the second light beam LB2 passes through the enabled second modulation area MA2, its polarization state remains in the second polarization state P2 (as shown in FIG. 10B ).

Fig. 11 is a cross-sectional schematic diagram of a first liquid crystal lens or a second liquid crystal lens according to another variant embodiment of the present invention. Referring to Fig. 11, different from the first liquid crystal lens 151 of Fig. 7A and the second liquid crystal lens 152 of Fig. 7B, in the variant embodiment of Fig. 11, the first liquid crystal lens 151A (or the second liquid crystal lens 152A) is, for example, an electrically controllable Fresnel lens.

In order to realize an optical path distribution similar to that required by a Fresnel lens in direction X or direction Z (such as the distribution of phase delay versus position as shown in FIG. 11 ), a plurality of electrodes E1”_1, E1”_2, ...., E1”_N of different sizes are provided on one side substrate of the liquid crystal lens, and an electrode E2” overlapping with the aforementioned plurality of electrodes E1”_1, E1”_2, ...., E1”_N is provided on the other side substrate. For example, a plurality of voltages can be applied to the plurality of electrodes E1”_1, E1”_2, ...., E1”_N, respectively, so that the molecular long axes of a plurality of liquid crystal molecules at different positions of the liquid crystal layer in direction X or direction Z form a specific arrangement distribution.

Since the effects of the first liquid crystal lens 151A and the second liquid crystal lens 152A of this embodiment on the incident light beam are similar to those of the first liquid crystal lens 151 in FIG. 7A and the second liquid crystal lens 152 in FIG. 7B , please refer to the relevant paragraphs of the aforementioned embodiments for detailed description, which will not be repeated here.

FIG. 12 is a schematic cross-sectional view of a display device according to the third embodiment of the present invention. Referring to FIG. 12 , the difference between the display device 10B of this embodiment and the display device 10 of FIG. 1 is that the type of polarization modulator is different. Specifically, in this embodiment, the polarization modulator used in the display device 10B is the polarization modulator 130A of FIG. 9A , not the polarization modulator 130 doped with a plurality of dye molecules DM in FIG. 4A . It is particularly noted that the polarization modulator 130A of this embodiment can also be replaced by the polarization modulator 130B of FIG. 10A and FIG. 10B . In order to allow the non-polarized light emitted by the self-luminous display panel (ie, the display panel 100 ) to have a polarization state before entering the polarization modulator 130A, the display device 10B of this embodiment further includes a polarizer POL between the display panel 100 and the polarization modulator 130A.

For example, the transmission axis of the polarizer POL may be parallel to the direction X. Therefore, after the non-polarized light from the display panel 100 passes through the polarizer POL, the electric field component whose polarization direction is perpendicular to the direction X or parallel to the direction Z will be absorbed by the polarizer POL, while the electric field component whose polarization direction is parallel to the direction X will pass through the polarizer POL to form the first light beam LB1 and the second light beam LB2 having the second polarization state P2.

In summary, in a display device of an embodiment of the present invention, when the first liquid crystal lens and the second liquid crystal lens are enabled, the maximum phase delay of the first liquid crystal lens to the first light beam having the first polarization state is different from the maximum phase delay of the second liquid crystal lens to the second light beam having the second polarization state. Accordingly, the first light beam and the second light beam having different polarization states can be focused at different positions after passing through the first liquid crystal lens and the second liquid crystal lens, and then present corresponding display images at different depths of field, so that the user can have a three-dimensional image visual experience when viewing.

10, 10A, 10B: display device 100, 100A: display panel 130, 130A, 130B: polarization modulator 131, 132, 151S1, 151S2, 152S1, 152S2: substrate 151, 151A: first liquid crystal lens 152, 152A: second liquid crystal lens AD1, AD2, AD3, AD4: alignment direction AL1: first alignment film AL2: second alignment film AL3: third alignment film AL4: fourth alignment film AX1, AX2: absorption axis d1, d2: thickness DM: dye molecule DM1: first part DM2: second part DS: display surface E1, E2, E1_1”, E1”_2, E1”_N, E2”, E1-A, E2-A, 151E1, 151E2, 152E1, 152E2: electrodes EF: electric field f1: first focal length f2: second focal length LB1: first light beam LB2: second light beam LCL-A, LCL-B: liquid crystal layer LCL1: first liquid crystal layer LCL2: second liquid crystal layer LCM, LCM-A, LCM-B: liquid crystal molecules LCM1: first liquid crystal molecules LCM2: second liquid crystal molecules MA1: first modulation area MA2: second modulation area OA1: first optical axis OA2: second optical axis P1: first polarization state P2: second polarization state POL: polarizer PR0, PR1, PR2: maximum phase delay USR: User V1: First voltage V2: Second voltage X, Y, Z: Direction

FIG. 1 is a schematic cross-sectional view of a display device according to a first embodiment of the present invention. FIG. 2 is a schematic front view of a polarization modulator of FIG. 1. FIG. 3 is a schematic diagram of polarization state distribution of multiple first light beams and multiple second light beams of FIG. 1 after passing through the polarization modulator of FIG. 2. FIG. 4A is a partially enlarged schematic diagram of the polarization modulator of FIG. 1 when it is not enabled. FIG. 4B is a partially enlarged schematic diagram of the polarization modulator of FIG. 1 when it is enabled. FIG. 5A and FIG. 5B are partially enlarged schematic diagrams of the first liquid crystal lens and the second liquid crystal lens of FIG. 1 when they are not enabled, respectively. FIG. 6A is a schematic front view of the first liquid crystal lens of FIG. 5A. FIG. 6B is a schematic front view of the second liquid crystal lens of FIG. 5B. FIG. 7A and FIG. 7B are partially enlarged schematic diagrams of the first liquid crystal lens and the second liquid crystal lens of FIG. 1 when they are enabled, respectively. FIG8 is a schematic cross-sectional view of a display device according to the second embodiment of the present invention. FIG9A is a partially enlarged schematic view of the polarization modulator of FIG8 when it is not enabled. FIG9B is a partially enlarged schematic view of the polarization modulator of FIG8 when it is enabled. FIG10A is a schematic cross-sectional view of another embodiment of the polarization modulator of FIG8 when it is not enabled. FIG10B is a schematic cross-sectional view of another embodiment of the polarization modulator of FIG8 when it is enabled. FIG11 is a schematic cross-sectional view of a first liquid crystal lens or a second liquid crystal lens according to another variant embodiment of the present invention. FIG12 is a schematic cross-sectional view of a display device according to the third embodiment of the present invention.

10: Display device

100: Display panel

130: Polarization modulator

151: First liquid crystal lens

152: Second liquid crystal lens

DS: Display Surface

f1: first focal length

f2: second focal length

LB1: First beam

LB2: Second beam

LCM1: first liquid crystal molecule

LCM2: Second liquid crystal molecule

MA1: First modulation area

MA2: Second modulation area

P1: first polarization state

P2: Second polarization state

USR: User

X, Y, Z: direction

Claims (10)

A display device comprises: a display panel having a display surface and being adapted to emit a first light beam and a second light beam; a polarization modulator disposed on one side of the display surface of the display panel and overlapping the display surface, the polarization modulator having a first modulation area and a second modulation area, wherein when the polarization modulator is enabled, the first light beam has a first polarization state after passing through the first modulation area, and the second light beam has a second polarization state after passing through the second modulation area. a second polarization state, the first polarization state being orthogonal to the second polarization state, wherein the polarization modulator comprises: a substrate; a plurality of first electrodes and a plurality of second electrodes, respectively disposed on the substrate; a plurality of liquid crystal molecules; and a plurality of dye molecules, dispersedly disposed between the liquid crystal molecules, the dye molecules comprising: a first portion, located in the first modulation region; and a second portion, located in the second modulation region, wherein when the polarization modulator is enabled, The absorption axis of the first portion is perpendicular to the absorption axis of the second portion, the polarization direction of the first polarization state is perpendicular to the absorption axis of the first portion, and the polarization direction of the second polarization state is perpendicular to the absorption axis of the second portion; and a first liquid crystal lens and a second liquid crystal lens are arranged on a side of the polarization modulator away from the display panel, the first liquid crystal lens is located between the polarization modulator and the second liquid crystal lens, When the first liquid crystal lens and the second liquid crystal lens are enabled, the first liquid crystal lens has a first maximum phase delay for the first light beam having the first polarization state, and the second liquid crystal lens has a second maximum phase delay for the second light beam having the second polarization state, and the first maximum phase delay is less than the second maximum phase delay, wherein the alignment direction of the first liquid crystal lens and the alignment direction of the second liquid crystal lens are perpendicular to each other. The display device as described in claim 1, wherein when the first liquid crystal lens and the second liquid crystal lens are enabled, the phase delay of the first liquid crystal lens to the second light beam having the second polarization state is zero, and the phase delay of the second liquid crystal lens to the first light beam having the first polarization state is zero. The display device as described in claim 1, wherein when the first liquid crystal lens and the second liquid crystal lens are enabled, the first liquid crystal lens has a first focal length for the first light beam having the first polarization state, the second liquid crystal lens has a second focal length for the second light beam having the second polarization state, and the first focal length is different from the second focal length. A display device as described in claim 1, wherein the polarization modulator is provided with a plurality of the first modulation zones and a plurality of the second modulation zones, the first modulation zones and the second modulation zones are arranged alternately along a first direction or a second direction, and the first direction is perpendicular to the second direction. The display device as described in claim 1, wherein the first liquid crystal lens comprises a first alignment film, a second alignment film, and a first liquid crystal layer sandwiched between the first alignment film and the second alignment film, the first alignment direction of the first alignment film and the second alignment direction of the second alignment film are parallel to the polarization direction of the first light beam after passing through the polarization modulator, the second liquid crystal lens comprises a third alignment film, a fourth alignment film, and a second liquid crystal layer sandwiched between the third alignment film and the fourth alignment film, the third alignment direction of the third alignment film and the fourth alignment direction of the fourth alignment film are parallel to the polarization direction of the second light beam after passing through the polarization modulator. A display device as described in claim 5, wherein the thickness and material of the first liquid crystal layer and the second liquid crystal layer are the same, and when the first liquid crystal lens and the second liquid crystal lens are enabled, a first voltage is applied to the first liquid crystal layer and has the first maximum phase retardation, and a second voltage is applied to the second liquid crystal layer and has the second maximum phase retardation, and the first voltage is different from the second voltage. The display device as described in claim 5, wherein the first liquid crystal lens further comprises a first substrate and two electrodes disposed on the first substrate, the two electrodes of the first liquid crystal lens are arranged along the first alignment direction of the first alignment film and the second alignment direction of the second alignment film, the second liquid crystal lens further comprises a second substrate and two electrodes disposed on the second substrate, the two electrodes of the second liquid crystal lens are arranged along the third alignment direction of the third alignment film and the fourth alignment direction of the fourth alignment film. The display device as described in claim 1, wherein the first liquid crystal lens has a first optical axis, the second liquid crystal lens has a second optical axis, and when the first liquid crystal lens and the second liquid crystal lens are enabled, the phase delay of the first liquid crystal lens gradually decreases as it moves away from the first optical axis, and the phase delay of the second liquid crystal lens gradually decreases as it moves away from the second optical axis. The display device as claimed in claim 1, wherein the first light beam and the second light beam emitted by the display panel each have the second polarization state, and when the polarization modulator is enabled, the polarization state of the first light beam changes from the second polarization state to the first polarization state after passing through the first modulation zone, and the polarization state of the second light beam remains in the second polarization state after passing through the second modulation zone. The display device as described in claim 1 further comprises: a polarizer disposed between the display panel and the polarization modulator, wherein the first light beam and the second light beam from the display panel each have the second polarization state after passing through the polarizer.

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