JPH1152284A - Scanning image observation device and optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device which is made small in size and light in weight and which gives an image onto a retina by making light forming a part of the image directly incident on an eye and performing scanning with the light, and a non-mechanical scanning optical element suitable for such a device. SOLUTION: This optical element 12 is formed by plurally laminating dynamic diffraction optical elements electrically switched to a state where light is deflected and a state where it is not deflected. By setting the deflecting angle of the dynamic diffraction optical element to a power system of two, the deflecting angle of the element 12 is optionaly selected. By changing the deflecting angle, scanning is performed with the light made incident on the retina. By laminating the dynamic diffraction optical elements so that their deflecting directions may be orthogonally crossed, two-dimensional scanning is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image observing apparatus which gives an image on a retina by scanning light which forms a part of an image into an observer's eye and scans the light. The present invention relates to an image observation apparatus that performs non-mechanical scanning of light and an optical element suitable for the scanning.

[0002]

2. Description of the Related Art A head mounted display (HMD) which is used by being mounted on a head and displaying an image in front of eyes is widely used in the field of virtual reality and flight simulation. HMD is a cathode ray tube (CRT) or liquid crystal display (L
CD) is generally used, and the real images displayed on these are observed as enlarged virtual images via an eyepiece optical system.

However, it is desirable that the HMD be small and light in terms of the form of use.
Is limited, and it is difficult to achieve both an increase in the range of the displayed image and an increase in the resolution of the image. Further, in addition to a CRT and an LCD, it is necessary to incorporate those drive circuits inside the HMD, so that the height and the weight are further increased. In particular, CRTs are not suitable for use in a human body because they are heavy and have a considerable thickness even if they are formed in a small size, and they require a high voltage.

[0004] As one method for solving such a problem,
A method of forming an image on the retina by directly making light forming a part of an image directly into an eye of a wearer of the device and scanning the light is proposed in US Pat. No. 5,596,339. In this method, light from a point light source is guided to a scanning optical system by an optical fiber, and light emitted from the light source is modulated according to a video signal, and raster scanning is performed in synchronization with the modulation. The scanning optical system includes a main scanning optical element and a sub-scanning optical element.

According to this method, an extremely high-resolution image which cannot be achieved by a CRT or an LCD having a limited pixel density can be provided to an observer by narrowing a light beam incident on an eye and finely adjusting a scanning angle. Can be provided. Further, a device for displaying a real image and its driving circuit are not required, and instead, the scanning optical system and its driving circuit are incorporated in a device mounted on the head.

An apparatus in which point light sources are arranged in an array to generate one-dimensional (linear) light forming a part of an image, and the linear light is made incident on an eye and scanned. Are known. The scanning here is performed only in one direction perpendicular to the linear light.

In general, for scanning light, a mechanical method for changing the direction and position of an optical element such as a reflecting mirror and a prism, and changing characteristics such as diffraction without changing the direction and position of the optical element. There are non-mechanical methods.

As optical elements for mechanical scanning, galvanometers and polygon mirrors have been known for a long time, and are usually driven by a motor. These mechanical scans have the feature that the scan angle is wide, but the scan speed is low, and they are often used in static image forming apparatuses such as copiers and printers. In recent years, attempts have been made to improve the scanning speed by using a resonance phenomenon or using a piezoelectric element as a driving element, but it is difficult to achieve both a wide scanning angle and a high scanning speed by mechanical scanning. It is in the current situation.

An acousto-optic (A / O) deflector is known as a non-mechanical scanning optical element.
The A / O deflector electrically generates a wave having a frequency of about a sound wave on the surface of a substrate formed as a flat plate, and causes the incident light to interfere with the vibration due to the vibration to deflect the light. Light is deflected in a plane along the substrate surface, and the deflection angle can be adjusted by changing the frequency of the surface. Therefore, the A / O deflector can perform one-dimensional scanning.

An optical element that non-mechanically deflects light includes a diffractive optical element utilizing a light diffraction phenomenon.
There is a dynamic diffractive optical element (dynamic DOE, D-DOE) that electrically switches between a state in which light is deflected and a state in which light is not deflected. The structure of the D-DOE is schematically shown in FIGS. FIG. 15 is a perspective view of the D-DOE, and FIG.
(A) is sectional drawing seen from the side. D-DOE
A base material 7 made of a transparent substance such as glass or resin and having one surface having a step-like uneven pattern with a minute width;
Are sandwiched between transparent plates 9 so that light incident from one transparent plate side is transmitted to the other transparent plate side. A voltage can be applied to the liquid crystal 8 from an electrode (not shown). The orientation of the liquid crystal 8 changes depending on the presence or absence of the applied voltage, thereby changing the refractive index.

The refractive index of the liquid crystal 8 is set to be equal to the refractive index of the substrate 7 when a voltage is applied or when no voltage is applied. No diffraction phenomenon occurs, and the incident light passes straight through the D-DOE without being deflected. When a difference occurs in the refractive index between the liquid crystal 8 and the substrate 7 by applying a voltage or removing the applied voltage, light is refracted at the interface between the two. Since there is a step with a very small width at the interface between the liquid crystal 8 and the base material 7, a phase difference occurs in the refracted light transmitted through the adjacent step, causing a diffraction phenomenon, and the light travels only in a specific direction. The light is thus deflected.

The direction of light deflection by the D-DOE is limited to a direction perpendicular to the step-like uneven pattern (right and left direction in FIG. 16), as is apparent from the principle of diffraction. D
The deflection angle of the light by the DOE is defined by the step-like uneven pattern of the substrate 7, the refractive index of the substrate 7, and the refractive index of the liquid crystal 8 in a state different from the refractive index of the substrate 7. These elements that define the deflection angle cannot be changed at the time of use, and the deflection angle of light becomes a constant value for each D-DOE.
The deflection angle can be set arbitrarily by the step-like uneven pattern of the base material 7. For example, in the D-DOE of FIG. 16B in which the pitch is smaller than that of FIG.
The deflection angle is larger.

[0013]

In the sub-scanning in the raster scanning, it is necessary to deflect all the light deflected in the main scanning direction, so that the optical element for the sub-scanning is necessarily large. Further, an optical element that scans linear light is also large.
The technique of the above-mentioned US Patent Publication performs the sub-scanning mechanically, and the technique of scanning linear light also performs the scanning mechanically. For this reason, a large-sized driving device is required, and it is difficult to sufficiently reduce the size and weight of the device. Moreover, raster scanning requires strict optical adjustment of two optical elements for main scanning and sub-scanning, which requires high assembly accuracy and is vulnerable to external impact. I have.

However, there is no known non-mechanical scanning optical element which is capable of scanning linear light or two-dimensionally scan point light, and which has a small, light and simple structure. . For example, although the A / O deflector can change the deflection angle at high speed, the deflection is limited to one-dimensional because of the incident angle dependency, and even if the A / O deflector is combined, Two-dimensional scanning cannot be performed.

The D-DOE can switch between deflecting transmitted light and proceeding straight without deflecting it at a high speed. However, since the deflection angle is constant, scanning cannot be performed. However, since it does not depend on the incident angle, not only point light and linear light but also two-dimensional (planar) light can be uniformly deflected in a certain direction. If the deflection angle can be arbitrarily adjusted, the value of use as an optical element for scanning becomes extremely high.

The present invention is directed to a small and lightweight device for directing light that forms part of an image into the eye and scanning the light to provide an image on the retina, and a non-mechanical device suitable for such a device. It is an object to provide a scanning optical element.

[0017]

In order to achieve the above object, according to the present invention, light forming a part of an image is guided to an observer's retina as point light, and the light is scanned in a first direction. In a scanning image observation apparatus that gives an image on the retina by performing main scanning and sub-scanning that shifts main scanning in a second direction different from the first direction, sub-scanning is performed non-mechanically. I do.

Further, in a scanning type image observation apparatus which guides linear light forming a part of an image to the retina of an observer and scans the linear light in one direction to give an image on the retina, scanning is performed in a non-scanning manner. Do it mechanically.

According to the present invention, an optical element is formed by stacking a plurality of diffractive elements capable of electrically switching between these two states, a state in which transmitted light is deflected by diffraction and a state in which transmitted light is not deflected. Is configured. That is,
A plurality of D-DOEs are stacked to form one optical element. The state of each diffraction element can be individually switched, and one or any two or more of the stacked diffraction elements can be in a state of deflecting light at the same time.

It is preferable that the plurality of diffractive elements to be laminated have different amounts of deflection. The amount of deflection of the optical element as a whole can be adjusted depending on which diffraction element is in a state of deflecting light. For example, if the amount of deflection of the diffraction element is set to a series that increases twice by two, such as θ, 2θ, and 4θ, the amount of deflection up to (2 ⁿ −1) θ can be determined in increments of θ by ⁿ diffraction gratings. Can be set. Since the switching of the state of each diffraction element is performed electrically, it is possible to increase or decrease the amount of deflection gradually at a very high speed, thereby scanning the light. Light to be scanned is not limited to point light, and may be linear light or planar light.

A plurality of diffraction elements may be stacked so that the deflection directions are different. For example, if the layers are stacked so as to be deflected in different first and second directions, light can be deflected in the first direction and further deflected in the second direction. It can be deflected in any direction. As described above, if the amount of deflection of the diffraction element is set differently, two-dimensional scanning of light becomes possible.

The above optical element can be used as a scanning optical element of a scanning type image observation apparatus that guides light to the retina of an observer and gives an image on the retina. In that case, the above optical element may be used alone or in combination with another scanning optical element.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical element and a scanning image observation apparatus according to the present invention will be described with reference to the drawings. FIG. 1 schematically shows the configuration of the observation device 1 according to the first embodiment. The observation apparatus 1 directly irradiates light forming a part of an image to the eye E of the wearer of the apparatus, modulates the light in accordance with an image signal, and scans the light in synchronization with the modulation, thereby directly on the retina. It gives an image and is also called a retinal display.

The retinal display 1 deflects point light in a first direction (horizontal direction), and changes the deflection angle (deflection amount) to scan the A / O deflector 11 and the A / O deflector 11.
Optical element 12 that transmits the light deflected by the optical element and deflects the light in the second direction (vertical direction), and electrically changes the deflection angle to scan the light. There is a pair of eyepieces 13 leading to E for each of the left and right eyes.

The A / O deflector 11, the optical element 12, and the eyepiece 13 are housed in a housing (not shown), and the observer wears this housing on the head for use. The point light that is two-dimensionally scanned by the A / O deflector 11 and the optical element 12 gives a two-dimensional image on the retina of the eye E of the observer, and the observer has a virtual image at a position away from the eye E by a predetermined distance. M will be observed. The size of the virtual image M is determined by the refractive power of the eyepiece 13, and the virtual image M having a size equal to or larger than the actual size of the optical element 12 can be observed.

FIG. 2 shows an A / O deflector 11 and an optical element 12.
FIG. 1 shows a perspective view of a scanning optical system 10 composed of: Scanning optical system 1
Light from a light source (not shown) is guided to a light source 0 by an optical fiber 14 having a small diameter.
1 obliquely enters the surface. The A / O deflector 11 has an oscillation circuit 11a for generating a wave having a frequency of about a sound wave on its surface.
The light incident on the A / O deflector 11 is diffracted by a wave on the surface, and is deflected horizontally along the surface. By changing the frequency of the wave generated by the oscillating circuit 11a, the deflection angle of the light is changed, thereby scanning the light.

The optical element 12 includes a plurality of D-DOEs 12a to
12f. Each of the D-DOEs 12a to 12f is stacked so as to deflect light in the same direction, and deflects light in a direction perpendicular to the surface of the A / O deflector 11. The pitch of the concavo-convex pattern of each of the D-DOEs 12a to 12f is set differently, and the respective deflection angles are θ,
2θ, 4θ, 8θ and 16θ.

These D-DOEs 12a to 12f include:
Voltages are individually applied so that a state in which light is deflected (hereinafter, referred to as a deflection state) and a state in which light is not deflected (hereinafter, referred to as a non-deflection state) can be individually switched. Thus, not only one arbitrary D-DOE is deflected and all other D-DOEs are deflected, but also two or more arbitrary D-DOEs are deflected and the remaining D-DOEs are deflected. A non-deflection state is also possible.

The overall deflection angle of the optical element 12 is determined by which of the D-DOEs 12a to 12f and which one is in the deflected state. The deflection angles of the optical element 12 are shown in Table 1 and FIG. In Table 1, "1" and "0" represent a deflected state and a non-deflected state of the D-DOE, respectively. In this way, by setting the deflection angles of the individual D-DOEs forming the optical element 12 in a series that increases by a factor of two, the deflection angles up to (2 ⁿ −1) θ in ⁿ D-DOEs Can be set in increments of θ.

Since the switching of the state of each D-DOE is performed electrically, it is possible to quickly increase or decrease the total deflection angle of the optical element 12, whereby
Scanning of light in the vertical direction can be performed at high speed.

FIG. 4 shows a circuit configuration for presenting an image on the retinal display 1. The retinal display 1 includes a light source unit 1
6, light modulation unit 17, main scanning unit 18M, sub-scanning unit 18S,
And a control unit 1 for controlling these based on a video signal
5 is provided.

The light source section 16 is composed of light emitting elements that emit red (R), green (G) and blue (B) light. The light emitted from the light source unit 16 is given to the scanning optical system 10 as point light, and the emitted light itself is emitted using a minute light emitting element such as a laser diode (LD) or a light emitting diode (LED). A configuration in which point light is used may be used, or a slightly larger light emitting element may be used, and the light may be condensed by a lens to generate point light. The control unit 15 causes the light source unit 16 to stop emitting light during the retrace period of the video signal.

The light modulator 17 modulates the light emitted from the light source 16. Specifically, the light modulating unit 17 has elements that can electrically change the transmittances of R, G, and B light, respectively, and the three-color light emitted by the light source unit 16 by these elements. The intensity is changed to adjust the mixing ratio of the three colors R, G, and B, and to adjust the intensity of the mixed light. The light modulation by the light modulator 17 is controlled by the controller 15 based on the video signal. The modulated light is guided to the scanning optical system 10 by the optical fiber 14 as described above.

The main scanning section 18M comprises an oscillation circuit 11a of the A / O deflector 11 and its driving circuit.
By changing the frequency of the wave emitted by 1a, A /
The scanning in the horizontal direction is performed by changing the deflection angle of the light by the O deflector 11. The sub-scanning unit 18S includes a drive circuit for each of the D-DOEs 12a to 12f included in the optical element 12, and changes the deflection angle of the optical element 12 by selecting the D-DOE to be deflected, thereby changing the vertical direction. Is scanned. The operations of the main scanning unit 18M and the sub-scanning unit 18S are controlled based on a horizontal synchronization signal and a vertical synchronization signal of a video signal, thereby performing a raster scan.

While the light emitted from the light source unit 16 is scanned by the main scanning unit 18M, the modulation by the light modulation unit 17 is performed every moment. Accordingly, the color and intensity of the point light that enters the eye E of the observer and moves on the retina changes in accordance with the image signal, whereby an image is provided to the observer.
Since the light emitting section 16 does not emit light during the flyback period, light that does not represent an image is not observed as noise.

FIG. 5 shows the configuration of the observation device 2 of the second embodiment.
Is shown schematically in FIG. This observation device 2 is also a retinal display that directly gives an image on the retina, but it does not scan two-dimensionally with point light, but scans one line of linear light that forms part of an image in the vertical direction. It is a configuration to do. The retinal display 2 includes an electric shutter array 21 made of PLZT and emitting linear light, an optical element 22 having the same configuration as the above-described optical element 12, and an eyepiece 23, one pair for each of the left and right eyes. I have. These are housed in a housing mounted on the head.

FIG. 6 is a perspective view of a scanning optical system 20 including an electric shutter array 21 and an optical element 22. A large number of lights from a light source (not shown) are guided to the scanning optical system 20 by an array 24 of small-diameter optical fibers. The electric shutter array 21 emits a line of point light provided from the optical fiber line 24 to the optical element 22 as linear light. Optical element 2
Reference numeral 2 scans by linearly deflecting the linear light by an angle corresponding to the deflected state and the non-deflected state of the D-DOEs 22a to 22f and changing the deflection angle.

FIG. 7 shows a circuit configuration for presenting an image on the retinal display 2. The retinal display 1 includes a light source unit 2
6, a light modulation unit 27, a scanning unit 28, and a control unit 25 for controlling these based on a video signal. The light source unit 26 includes a number of sets of light emitting elements that emit R, G, and B lights, and the light modulation unit 27 includes a number of sets of modulation elements equal to the number of light emitting elements of the light source unit 26. Light emitted from each set of light emitting elements of the light source unit 26 is individually modulated based on one line of video signal, and is provided to the electric shutter array 21 via the individual optical fibers of the optical fiber array 24.
The scanning unit 28 has the same configuration as the sub-scanning unit 18S of the first embodiment, and operates similarly.

In this embodiment, the light emitting section 2 is also provided during the flyback period.
Although the light emission of No. 6 is stopped so that noise does not appear, the control unit 25 may close the electric shutter array 21 instead of stopping the light emission.

In the retinal displays 1 and 2 of the first and second embodiments, the light representing one point of the image is incident on the observer's eyes as a minute light beam. The state where the observer turns his or her eyes directly in front, that is, the eyepieces 13 and 23
In the state where the optical axis passes through the center of the pupil, the light flux deflected in any direction reaches the retina, so that the entire image can be observed. However, when the observer changes the direction of the eye and the optical axes of the eyepieces 13 and 23 do not pass through the center of the pupil, the light flux does not pass through the pupil depending on the deflected direction, and the periphery of the observed image is not observed. There is a risk that the part will be chipped.

According to the observation apparatus of the third embodiment described below, such inconvenience does not occur. FIG. 8 schematically shows the configuration of the observation device 3 according to the third embodiment. This observation device 3 is also a retinal display, and scans two-dimensionally while modulating point light with a video signal, as in the first embodiment. The retinal display 3 has a pair of left and right collimator lenses 31, optical elements 32, and eyepieces 33, each of which is housed in a housing mounted on the head.

Collimator lens 31 and optical element 32
Light from a light source (not shown) is guided to a scanning optical system 30 by a small-diameter optical fiber 34. The collimator lens 31 converts the point light into a light having a diameter larger than that of the human pupil EP.
The light is given to the optical element 32 as a parallel light flux of about 0 mmφ.

FIG. 9A is a perspective view of the optical element 32. FIG. The optical element 32 is formed by stacking a plurality of D-DOEs 32a to 32j. Optical element 1 of first and second embodiments
2 and 22, the deflection directions of the D-DOEs are set to be the same. However, in the optical element 32 of the present embodiment, the D-DOEs 32a to 32j deflect light in directions orthogonal to each other.
Are laminated. The D-DOEs 32a to 32e deflect light in the horizontal direction, and the D-DOEs 32f to 32j deflect light in the vertical direction. The deflection angles of the D-DOEs 32a to 32e are set to increase by a factor of two.
The deflection angles of E32f to 32j are also set so as to increase by two times.

The optical element 32 having such a structure can deflect light in the horizontal direction and in the vertical direction, and can change the respective deflection angles.
Light can be scanned two-dimensionally. Hereinafter, the optical element 3
2 is also called a two-dimensional diffractive optical element (2D-DOE). Note that, as shown in FIG.
-DOE and D-DOE which deflects in the vertical direction may be alternately stacked. Also, the number of D-DOEs that deflect in the horizontal direction and the number of D-DOEs that deflect in the vertical direction do not need to be the same, and may be determined according to the angle of view or resolution in the horizontal and vertical directions.

The parallel light beams incident on the two-dimensional diffractive optical element 32 from the collimator lens 31 are converted into respective D-DOEs 32a to 32d.
The light is deflected according to the setting of the deflected state and the non-deflected state of 32j. However, due to the nature of the D-DOE, the deflection is uniform for a large-diameter light beam. Therefore, the light beam diameter does not change even after passing through the two-dimensional diffractive optical element 32, and the light beam enters the eyepiece 33 as a parallel light beam. The eyepiece 33 guides the incident light beam to the eye E of the observer without causing a large diameter change. Therefore, the observer does not face the eye E to the front,
Even when the optical axis of the eyepiece 33 does not pass through the center of the pupil EP, the pupil EP enters the light beam, and much light passes through the pupil EP.

Since the light incident on the eye E is imaged on the retina by the lens, the point light guided by the optical fiber 34 reaches the retina as point light. In addition, the amount of light is substantially constant regardless of the direction of the eye E, and the observer can observe the entire image even when the eye E is not facing straight.

FIG. 10 shows a circuit configuration for presenting an image on the retinal display 3. The retinal display 3 includes a light source unit 3
6, light modulation section 37, main scanning section 38M, sub-scanning section 38S,
And a control unit 3 for controlling these based on a video signal
5 is provided.

The light source section 36 and the light modulation section 37 have the same configuration as the light source section 16 and the light modulation section 17 of the first embodiment, and operate similarly. The main scanning section 38M and the sub-scanning section 38S are respectively provided by the D-
DOEs 32a to 32e and D-DOEs 32f to 32j
Drive circuit. Raster scanning is performed by the main scanning unit 38M changing the horizontal deflection angle of the optical element 32 and the sub-scanning unit 38S changing the vertical deflection angle of the optical element 32. These scans are controlled based on the horizontal and vertical synchronization signals of the video signal.

In any of the above-described retinal displays, the control unit, the light source unit, and the light modulation unit include:
It is housed in a housing different from the housing housing the scanning optical system and the eyepiece, and both housings are connected by an optical fiber and a signal transmission cable. Therefore, the member mounted on the head is small and lightweight.

The two-dimensional diffractive optical element 32 in which a plurality of D-DOEs are stacked so as to have different deflection directions is not limited to a retinal display, but is used for scanning of a projection type display device for projecting light onto a screen to display an image. Can also be used as an optical element. Hereinafter, an example in which the two-dimensional diffractive optical element 32 is used for this purpose will be described.

The fourth embodiment shown in FIG. 11 uses the two-dimensional diffractive optical element 32 alone in the scanning optical system. The light modulated by the video signal is transmitted through an optical fiber 51.
Then, the light is incident on the optical element 32 as point light, and the screen 52 is two-dimensionally scanned.

The fifth and sixth embodiments shown in FIGS. 12 and 13 combine a two-dimensional diffractive optical element 32 with a reflection mirror 53 driven by a motor 54 to perform mechanical scanning, thereby forming a point-like light. Is scanned. Optical element 32
Can scan both in the horizontal direction and the vertical direction, and can perform scanning in both directions at a very high speed, so that it can be used for both main scanning and sub-scanning.

Therefore, in these embodiments, the main scanning is performed by the reflection mirror 53 and the sub-scanning is performed by the optical element 32, and the main scanning is performed by the optical element 32 and the sub-scanning is performed by the reflection mirror 53. Either can be selected. However, in mechanical scanning, it is difficult to achieve both a wide scanning angle and a high scanning speed. Therefore, when displaying an image with a wide angle of view, the two-dimensional diffractive optical element 32 is used for main scanning. Advantageously.

Also in the projection type display device, the above-mentioned A / O
The deflector 11 can be used. This embodiment is shown in FIG.
It is shown in FIG. However, since the A / O deflector can perform only one-dimensional scanning, it is used only for main scanning.

The image observation apparatus which gives an image to a human retina or a screen by scanning light modulated in accordance with a video signal has been described above.
The present invention can be used not only for a video signal such as a television signal and a video camera signal but also for a virtual video generated by a computer, for example.

The two-dimensional diffractive optical element 32 can deflect light in an arbitrary direction and at an arbitrary angle, and can switch the light at a high speed. The present invention can be applied not only to raster scanning in which the scanning direction is fixed, but also to random scanning in which scanning is performed in an unspecified direction. In this case, it is necessary to perform scanning by explicitly specifying the start point and the end point of the scanning, instead of switching the scanning by the synchronization signal, and the video is represented by a method different from a normal video signal. When an image is generated by a computer, it is easy to use such a signal, and in the field of virtual reality, random scanning by the two-dimensional diffractive optical element 32 has a high practical value.

[0057]

[Table 1]

[0058]

According to the scanning image observation apparatus of the first aspect, there is no need to provide a mechanical driving device such as a motor for sub-scanning, and the apparatus can be made compact and lightweight. Therefore, even when the apparatus is used by being mounted on the head, the physical burden on the observer is reduced. In addition, since the duration of a visual signal when a person receives light on the retina is limited, it is difficult to recognize the entire image at the same time when scanning at a low speed. However, in non-mechanical scanning, a wide scanning angle and a high scanning speed can be compatible, so that even an image with a wide angle of view can be observed without deteriorating the quality. .

The same effect as described above can be obtained with the scanning image observation apparatus of the second aspect.

According to the optical element of the third aspect, it is possible to individually control and switch between the deflecting state and the non-deflecting state of the laminated diffraction elements, so that diffraction elements having different deflection amounts and deflection directions are used. Accordingly, the deflection of light can be easily adjusted with a single optical element. In addition, since the switching between the deflected state and the non-deflected state is performed electrically, the deflection can be adjusted very quickly.

According to the optical element of the fourth aspect, since the deflection amount can be changed very quickly, light can be scanned at a high speed.

In the optical element according to the fifth aspect, light can be deflected in an arbitrary direction depending on the direction of deflection of each of the stacked diffraction gratings.

The scanning type image observation apparatus according to the sixth aspect is an apparatus which is small, lightweight, and capable of high-speed scanning.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of a retinal display according to a first embodiment.

FIG. 2 is a perspective view showing a scanning optical system of the retinal display according to the first embodiment.

FIG. 3 is a diagram showing a deflection angle of an optical element formed by laminating dynamic diffraction gratings having different deflection angles.

FIG. 4 is a diagram showing a circuit configuration of the retinal display according to the first embodiment.

FIG. 5 is a diagram schematically illustrating a configuration of a retinal display according to a second embodiment.

FIG. 6 is a perspective view showing a scanning optical system of a retinal display according to a second embodiment.

FIG. 7 is a diagram showing a circuit configuration of a retinal display according to a second embodiment.

FIG. 8 is a diagram schematically illustrating a configuration of a retinal display according to a third embodiment.

FIG. 9 is a perspective view showing an optical element formed by laminating dynamic diffraction gratings having different deflection angles so as to have different deflection directions.

FIG. 10 is a diagram illustrating a circuit configuration of a retinal display according to a third embodiment.

FIG. 11 is a diagram showing a first configuration of a projection display device using an optical element formed by laminating dynamic diffraction gratings in a scanning optical system.

FIG. 12 is a diagram showing a second configuration of a projection display device using an optical element formed by laminating dynamic diffraction gratings in a scanning optical system.

FIG. 13 is a diagram showing a third configuration of a projection display apparatus using an optical element formed by laminating dynamic diffraction gratings in a scanning optical system.

FIG. 14 is a diagram showing a configuration of a projection display device using an acousto-optic deflector for a scanning optical system.

FIG. 15 is a perspective view of a dynamic diffraction grating.

FIG. 16 is a sectional view of a dynamic diffraction grating.

[Explanation of symbols]

 Reference Signs List 1 retinal display 10 scanning optical system 11 acousto-optic (A / O) element 12 optical element 12a to 12f dynamic diffractive optical element (D-DOE) 13 eyepiece 14 optical fiber 2 retinal display 20 scanning optical system 21 electric shutter array 22 optical Element 22a to 22f Dynamic Diffractive Optical Element (D-DOE) 23 Eyepiece 24 Optical Fiber Array 3 Retina Display 30 Scanning Optical System 31 Collimator Lens 32 Two-Dimensional Diffractive Optical Element (2D-DOE) 32a to 32j Dynamic Diffractive Optical Element ( D-DOE) 33 eyepiece 34 optical fiber 51 optical fiber 52 screen 53 reflecting mirror 54 motor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Ishibashi 2-3-13 Azuchicho, Chuo-ku, Osaka City Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Yasushi Kobayashi 2-3-3 Azuchicho, Chuo-ku, Osaka City No. 13 Osaka International Building Minolta Co., Ltd. (72) Inventor Satoshi Osawa 2-3-13 Azuchicho, Chuo-ku, Osaka-shi Osaka International Building Minolta Co., Ltd. (72) Inventor Yasushi Yajiri 2-Chome Azuchicho, Chuo-ku, Osaka-shi No. 3-13 Osaka International Building Minolta Co., Ltd. (72) Inventor Takatoshi Ishikawa 2-13-13 Azuchicho, Chuo-ku, Osaka City Osaka International Building Minolta Co., Ltd.

Claims (6)

[Claims] 1. A main scan that guides light forming a part of an image to a retina of an observer as point light, scans the light in a first direction, and performs a main scan that is different from the first direction. A scanning image observation apparatus for providing an image on the retina by performing sub-scanning shifted in the direction of 2, wherein the sub-scanning is performed non-mechanically. 2. A scanning-type image observation apparatus which guides linear light forming a part of an image to a retina of an observer and scans the linear light in one direction to give an image on the retina. A scanning image observation apparatus characterized by performing non-mechanically. 3. A state in which transmitted light is deflected by diffraction, and a state in which transmitted light is not deflected.
An optical element comprising a plurality of diffraction elements that can be electrically switched between two states. 4. The optical element according to claim 3, wherein the plurality of diffraction elements have different amounts of deflection. 5. The optical element according to claim 3, wherein the plurality of diffraction elements are stacked so as to have different deflection directions. 6. An optical element according to claim 3, which scans light by deflection thereof, guides the scanned light to a retina of an observer, and gives an image on the retina. A scanning image observation device characterized by the following.