Image display device

Abstract

Provided is an image display device with which a high-resolution image of a wide visual field can be generated while achieving reduced size of the device.　The present invention provides an image display device comprising: a display panel that generates image light; an optical system that transmits image light having a prescribed polarization direction and guides the image light to the pupil of an observer; a reflection plate that reflects, of the image light from the display panel, image light corresponding to a first region in the field of view of the observer toward the optical system; and a polarization control unit that switches the polarization direction of the image light, the polarization control unit alternately switching between an image light polarization direction corresponding to the first region and an image light polarization direction corresponding to a second region different from the first region in the field of view of the observer.

Description

Image display device

[0001] The technology according to the present disclosure (hereinafter also referred to as "the technology") relates to an image display device.

[0002] BACKGROUND ART Conventionally, in technical fields related to Extended Reality (XR) such as Virtual Reality (VR) and Augmented Reality (AR), a technology for generating an image by projecting image light onto the pupil has been used.

[0003] For example, Patent Document 1 discloses technology relating to "an optical unit for a head-mounted display device, comprising: a light-emitting section that collects light emitted from a light source; a display section that generates image light using the light collected by the light-emitting section as illumination light; a projection lens that projects the image light from the display section; an optical axis conversion element that displaces the optical axis of the image light projected from the projection lens; and a light guide plate that receives the image light, the optical axis of which has been displaced by the optical axis conversion element, and guides it to the pupil of the wearer."

[0004] In Patent Document 1, an MEMS mirror, a liquid crystal panel in which the refractive index of each cell is changed, or the like is used as the optical axis conversion element.

[0005] Japanese Patent Application Laid-Open No. 2022-160182

[0006] However, when the optical axis is displaced using the technique disclosed in Patent Document 1, the image may become invisible due to the displacement of the optical axis or the rotation of the eyeball.

[0007] Furthermore, when a MEMS mirror is used as the optical axis conversion element, the device may become large in size. When a liquid crystal panel with a different refractive index for each cell is used as the optical axis conversion element, it may be difficult to generate a high-resolution image due to the limited number of pixels.

[0008] For example, in virtual reality (VR) applications, miniaturizing display panels requires bending the image light, which increases the optical power. To address this issue, pancake optical systems with internal reflective surfaces are used, but there are limitations.

[0009] To improve the PPD (Pixels Per Degree) near the center, it is preferable to employ an optical system that focuses image light from many pixels on the display panel in the viewer's central vision. However, if image light from many pixels is focused in the central vision, it becomes difficult for the image light to enter the viewer's peripheral vision. If image light is directed into the viewer's peripheral vision, there is a risk of a decrease in resolution.

[0010] Therefore, a main object of the present technology is to provide an image display device that can generate a high-resolution image with a wide field of view while achieving a miniaturization of the device.

[0011] The present technology provides an image display device including: a display panel that generates image light; an optical system that transmits the image light of a predetermined polarization direction and guides it to a viewer's pupil; a reflector that reflects, of the image light from the display panel, image light corresponding to a first region in the viewer's field of view toward the optical system; and a polarization control unit that switches the polarization direction of the image light, wherein the polarization control unit alternately switches the polarization direction of the image light corresponding to the first region and the polarization direction of image light corresponding to a second region in the viewer's field of view that is different from the first region. The image display device may further include a polarization conversion unit that converts the polarization direction of the image light from the display panel. The polarization conversion unit may be disposed outside the display panel and perpendicular to the display panel, and the polarization conversion unit and the reflector may be stacked in order from the side where the image light is incident. The optical system may satisfy the following formula (1): s / 2=(l+q)·tan(α) (1) where s is the width of the display panel, l is the width of the reflector, q is the length of the gap between the reflector and the display panel, and α is the angle formed between the reflector and a line segment connecting the center of the display panel and the end of the reflector on the optical system side. The optical system may include a polarization transmission unit that selectively transmits linearly polarized light and a lens. The display panel, the polarization control unit, and the polarization conversion unit may be stacked in the order in which the image light passes through. The optical system may include a diffractive lens based on a geometric phase. The reflector may be disposed between the pupil and the optical system, and between the optical system and the polarization control unit. The optical system may include a polarization transmission unit that selectively transmits linearly polarized light and a lens, and a polarization conversion unit that converts the polarization direction of the image light from the display panel may be disposed between the optical system and the polarization control unit. The optical system may include a diffractive lens based on a geometric phase. The reflector may be disposed at an angle with respect to a direction perpendicular to the display panel, and the following formula (2) may be satisfied, where s is the width of the display panel, l is the width of the reflector, q is the length of the gap between the reflector and the display panel, and β is the angle of inclination of the reflector.l sin β + s / 2 = (l cos β + q) tan(2β) (2) The optical system may transmit a portion of the image light and reflect a portion of the image light toward the reflector. The optical system may be integrally molded to include a polarization conversion unit that converts the polarization direction of the image light from the display panel and a polarization transmission unit that selectively transmits linearly polarized light. The optical system may transmit a portion of the image light and reflect a portion of the image light toward the reflector, and the reflector may reflect a portion of the image light toward the optical system and a portion of the image light toward the pupil. An optical element that changes the direction of the image light may be disposed between the display panel and the reflector. The optical system may further include an image control unit that synchronizes the timing at which the display panel switches the image light with the timing at which the polarization control unit switches the polarization direction. The image control unit may invert an image corresponding to the first region. The image control unit may turn off the display panel at a timing when an image corresponding to the first area and an image corresponding to the second area are switched. The first area may be a peripheral visual field, and the second area may be a central visual field.

[0012] According to the present technology, it is possible to provide an image display device that can generate a high-resolution image with a wide field of view while miniaturizing the device. Note that the effects described herein are not necessarily limited to those described herein, and may be any of the effects described in the present disclosure.

[0013] FIG. 1 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology. FIG. 2 is an explanatory diagram showing an operation example of the image display device 100 according to an embodiment of the present technology. FIG. 3 is a schematic diagram showing an example of an image displayed by the image display device 100 according to an embodiment of the present technology. FIG. 4 is a schematic diagram showing a configuration example of a polarization control unit 5 according to an embodiment of the present technology. FIG. 5 is a flowchart showing an operation example of the image display device 100 according to an embodiment of the present technology. FIG. 6 is a graph showing an operation example of the image display device 100 according to an embodiment of the present technology. FIG. 7 is a schematic diagram showing an operation example of the image display device 100 according to an embodiment of the present technology. FIG. 8 is a schematic diagram showing an example of a configuration of the image display device 100 according to an embodiment of the present technology. FIG. 9 is a schematic diagram showing an example of a configuration of the image display device 100 according to an embodiment of the present technology. FIG. 10 is a schematic diagram showing an example of a configuration of the image display device 100 according to an embodiment of the present technology. 1 is a schematic diagram illustrating a configuration example of an image display device 100 according to an embodiment of the present technology; FIG. 2 is a schematic diagram illustrating a configuration example of an optical element 8 according to an embodiment of the present technology;

[0014] Hereinafter, preferred embodiments for implementing the present technology will be described with reference to the drawings. Note that the embodiment described below shows an example of a typical embodiment of the present technology, and does not limit the scope of the present technology. In addition, the present technology can be combined with any of the following examples and their modifications.

[0015] In the following description of the embodiments, configurations may be described using terms including "approximately," such as "approximately parallel" and "approximately perpendicular." For example, "approximately parallel" does not only mean completely parallel, but also means substantially parallel, i.e., including a state where the orientation is deviated from the completely parallel state by, for example, a few percent. The same applies to other terms including "approximately." Furthermore, each figure is a schematic diagram and is not necessarily an accurate depiction. The scale of the drawings has been exaggerated to make the features of the technology easier to understand. Therefore, it should be noted that the scale of the drawings and the scale of the actual device are not necessarily the same.

[0016] Unless otherwise specified, in the drawings, "top" means the top or upper side in the drawing, "bottom" means the bottom or lower side in the drawing, "left" means the left or left side in the drawing, and "right" means the right or right side in the drawing. Furthermore, in the drawings, the same or equivalent elements or members are given the same reference numerals, and redundant explanations will be omitted.

[0017] The description will be given in the following order: 1. First embodiment of the present technology (example 1 of image display device) (1) Overall configuration (2) Operation example (3) Polarization control unit 2. Second embodiment of the present technology (example 2 of image display device) 3. Third embodiment of the present technology (example 3 of image display device) 4. Fourth embodiment of the present technology (example 4 of image display device) 5. Fifth embodiment of the present technology (example 5 of image display device) 6. Sixth embodiment of the present technology (example 6 of image display device) 7. Seventh embodiment of the present technology (example 7 of image display device) 8. Eighth embodiment of the present technology (example 8 of image display device) 9. Ninth embodiment of the present technology (example 9 of image display device) 10. Tenth embodiment of the present technology (example 10 of image display device)

[0018] [1. First Embodiment of the Present Technology (Example 1 of Image Display Device)] [(1) Overall Configuration] The present technology provides an image display device including: a display panel that generates image light; an optical system that transmits image light in a predetermined polarization direction and guides it to a pupil of a viewer; a reflector that reflects, of the image light from the display panel, image light that corresponds to a first region in the view of the viewer, toward the optical system; and a polarization control unit that switches the polarization direction of the image light transmitted by the optical system, wherein the polarization control unit alternately switches the polarization direction of the image light that corresponds to the first region and the polarization direction of the image light that corresponds to a second region in the view of the viewer that is different from the first region.

[0019] A configuration example of an image display device according to an embodiment of the present technology will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0020] As shown in FIG. 1, the image display device 100 includes a display panel 1 , an optical system 2 , a polarization conversion unit 3 , a reflector 4 , and a polarization control unit 5 .

[0021] The display panel 1 generates image light. Specifically, the display panel alternately generates image light corresponding to a first region in the viewer's field of view and image light corresponding to a second region different from the first region in the viewer's field of view. The first region may be, for example, peripheral vision. The second region may be, for example, central vision.

[0022] An observer's visual field includes central and peripheral vision. Central vision is the area located at the center of vision. This area is particularly suited to capturing detailed visual information, focusing on objects and supporting high-precision visual recognition. On the other hand, peripheral vision refers to the area of ​​vision outside the central field, usually located on the outer side of the visual field. This area has a lower ability to provide detailed visual information compared to central vision and is primarily used to detect movement and wide scenery.

[0023] The polarization control unit 5 switches the polarization direction of the image light in synchronization with the display panel 1. In particular, the polarization control unit 5 alternately switches the polarization direction of the image light corresponding to a first region in the viewer's field of view and the polarization direction of the image light corresponding to a second region in the viewer's field of view that is different from the first region.

[0024] In this configuration example, the polarization conversion unit 3 is disposed outside the display panel 1 and in the vertical direction of the display panel 1. The polarization conversion unit 3 and the reflector 4 are layered in this order from the side where image light is incident. This schematic diagram is a view from above the viewer. Therefore, the polarization conversion unit 3 and the reflector 4 are disposed on the left and right sides as viewed from the viewer.

[0025] The polarization conversion unit 3 converts the polarization direction of the image light from the display panel 1. The polarization conversion unit 3 can be, for example, a wave plate. A wave plate is made of a plurality of refractive materials and can rotate the polarization direction of linearly polarized light or convert linearly polarized light into circularly polarized light. It is preferable to use a wave plate whose rotational transmittance is less likely to vary depending on the angle of incidence.

[0026] Wave plates that can be used include, for example, half-wave plates (HWPs) and quarter-wave plates (QWPs). HWPs rotate the polarization direction of linearly polarized light by 180 degrees. Linearly polarized light that passes through an HWP is polarized perpendicular to its incident polarization direction. QWPs convert linearly polarized light into circularly polarized light.

[0027] The shape of the wave plate is not particularly limited, and may be, for example, a plate or a film.

[0028] The image light from the polarization control unit 5 passes through the polarization conversion unit 3, is reflected by the reflector 4, and passes through the polarization conversion unit 3 again. For example, when the image light from the polarization control unit 5 is S-polarized light, which is linearly polarized light, this S-polarized light is converted into right-handed circularly polarized light by passing through the polarization conversion unit 3. The image light converted into right-handed circularly polarized light is then reflected by the reflector 4 and converted into left-handed circularly polarized light. The image light converted into left-handed circularly polarized light is then converted into P-polarized light, which is linearly polarized light, by passing through the polarization conversion unit 3 again. In this way, the S-polarized light output from the polarization control unit 5 is converted into P-polarized light. In other words, when the image light output from the polarization control unit 5 directly to the pupil (particularly the central visual field) is S-polarized, the image light guided to the pupil (particularly the peripheral visual field) via the polarization conversion unit 3 and the reflector 4 becomes P-polarized.

[0029] The reflector 4 reflects, out of the image light from the display panel 1, image light corresponding to a first region (for example, peripheral vision) in the viewer's field of view, toward the optical system 2. This image light is displayed as an image (virtual image) in the first region (for example, peripheral vision) of the viewer. On the other hand, out of the image light from the display panel 1, image light that does not pass through the reflector 4 is displayed as an image (virtual image) in a second region (for example, central vision) of the viewer. Note that the reflector 4 may also reflect the image light corresponding to the second region toward the optical system 2.

[0030] The optical system 2 transmits image light of a predetermined polarization direction and guides it to the observer's pupil. In this configuration example, the optical system 2 includes a polarization transmission unit 21 that selectively transmits linearly polarized light, and a lens 22. The polarization conversion unit 3 is, for example, a polarizer, and selectively transmits linearly polarized S-polarized light or P-polarized light. The lens 22 guides the image light to the observer's pupil.

[0031] When the width of the display panel 1 is s, the width of the reflector 4 is l, the length of the gap between the reflector 4 and the display panel 1 is q, and the angle formed by the line segment connecting the center of the display panel 1 and the end of the reflector 4 on the optical system 2 side and the reflector 4 is α, it is preferable that the following formula (1) be satisfied.

[0032] s / 2=(l+q)・tan(α)...(1)

[0033] Satisfying this formula improves the peak luminance distribution near the center of the display panel 1. As a result, image light from near the center of the display panel 1 more easily reaches the pupil.

[0034] (2) Operation Example An operation example of the image display device 100 will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram showing an operation example of the image display device 100 according to an embodiment of the present technology.

[0035] 2A shows the polarization of image light corresponding to the second region (e.g., central visual field). As shown in FIG. 2A, for example, the display panel 1 generates image light corresponding to the second region (e.g., central visual field). The polarization control unit 5 converts the polarization direction of this image light to P-polarized light. The image light converted by the polarization control unit 5 is guided to the second region in the observer's field of view via the optical system 2, without passing through the polarization conversion unit 3. The optical system 2 transmits P-polarized light. As a result, the image light is guided to the second region, allowing the observer to observe an image corresponding to the second region. In other words, an image corresponding to the second region is displayed in the second region in the observer's field of view.

[0036] At this time, this image light is reflected by the reflector 4 or the like, and when it passes through the polarization conversion unit 3, it is converted from P-polarized light to S-polarized light. Since the optical system 2 does not transmit S-polarized light, the image light is not guided to the first region. Therefore, an image corresponding to the second region is not displayed in the first region of the observer.

[0037] 2B shows the polarization of image light corresponding to a first region (e.g., peripheral vision). As shown in FIG. 2B, the display panel 1 generates image light corresponding to the first region (e.g., peripheral vision). The polarization control unit 5 converts the polarization direction of this image light into S-polarized light. When this image light is reflected by a reflector 4 or the like and passes through the polarization conversion unit 3, it is converted from S-polarized light to P-polarized light. Because the optical system 2 transmits P-polarized light, the image light is guided to the first region. The viewer can observe an image corresponding to the first region. That is, an image corresponding to the first region is displayed in the first region in the viewer's field of view.

[0038] On the other hand, because the optical system 2 does not transmit S-polarized light, the image light that reaches the optical system 2 without being reflected by the reflector 4 or the like does not transmit through the optical system 2. In other words, the image light is not guided to the second region. As a result, an image corresponding to the first region is not displayed in the second region in the viewer's field of view.

[0039] The state shown in FIG. 2A and the state shown in FIG. 2B are alternately switched.

[0040] An example of the operation of the image display device 100 will be further described with reference to Fig. 3. Fig. 3 is a schematic diagram showing an example of an image displayed by the image display device 100 according to an embodiment of the present technology. To simplify the description, an example in which the first region is the peripheral visual field and the second region is the central visual field will be described below.

[0041] Fig. 3A shows an image displayed in the central visual field of the observer. Fig. 3B shows an image displayed in the peripheral visual field of the observer. The display panel 1 (see Fig. 1) alternately generates image light of the image shown in Fig. 3A and image light of the image shown in Fig. 3B.

[0042] 3C and 3D are schematic diagrams showing how an observer views an image using the image display device 100. In Fig. 3C, an image corresponding to the central visual field is displayed, but an image corresponding to the peripheral visual field is not displayed.

[0043] On the other hand, in Fig. 3D, an image corresponding to the peripheral vision is displayed via the reflector 4 (see Fig. 1) or the like, but an image corresponding to the central vision is not displayed. The image corresponding to the peripheral vision is reflected by the reflector 4, and is therefore a horizontally inverted version of the image shown in Fig. 3B. An image control unit, which will be described later, inverts the image corresponding to the peripheral vision.

[0044] The image shown in Figure 3C and the image shown in Figure 3D are alternately displayed, allowing the viewer to view the image shown in Figure 3E. In this way, the image display device 100 can generate high-resolution images with a wide field of view despite its compact size. This effect also occurs in other embodiments described below. Therefore, repeated description may be omitted in the description of other embodiments.

[0045] Furthermore, according to this embodiment, the chief rays of the image light from the display panel are concentrated in the central visual field of the viewer, so that the PPD (Pixels Per Degree) near the center can be improved.

[0046] In this configuration example, the reflector 4 is disposed to the left and right of the viewer, but it may also be disposed above and below the viewer. In this case, it is preferable that the display panel 1 generates image light that is inverted in the vertical direction.

[0047] Alternatively, the second region may be peripheral vision and the first region may be central vision. Furthermore, the second region and the first region may be other visual fields than central vision and peripheral vision, including, for example, dark vision, blind spots, and afterimage vision.

[0048] Furthermore, an image corresponding to the first region may be displayed in a second region of the observer. An image corresponding to the second region may be displayed in the first region of the observer. The second region and the first region may partially overlap. For example, a portion of the second region may be included in the first region, or a portion of the first region may be included in the second region.

[0049] (3) Polarization Control Unit An example of the configuration of the polarization control unit 5 will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing an example of the configuration of the polarization control unit 5 according to an embodiment of the present technology.

[0050] 4, the polarization control unit 5 has transparent electrodes 52 arranged on both sides of a liquid crystal 51. The transparent electrodes 52 contain a conductive material such as ITO, ZnO, or PEDOT. A polarizer 53 is arranged on the surface of the transparent electrode 52 that faces a display panel (not shown).

[0051] An image control unit 6 is connected to each transparent electrode 52. A power source 7 is connected to this image control unit 6. This image control unit 6 applies a voltage to the liquid crystal 51 via each transparent electrode 52, thereby changing the polarization direction of the liquid crystal 51.

[0052] Although not shown, a spatial light modulator (SLM) or the like may be further used to control the polarization direction of the image light.

[0053] Furthermore, although the polarization control unit 5 is configured using liquid crystal as an example configuration, the configuration is not limited to this. For example, an electro-optical crystal may be used as the polarization control unit 5. An electro-optical crystal is a polarizing element that utilizes the property that electrical resistance changes depending on the polarization state of light. An electro-optical crystal can pass current or generate voltage depending on the polarization state of incident light. Electro-optical crystals have the advantages of high polarization transmittance and being usable over a wide wavelength range.

[0054] The image control unit 6 synchronizes the timing at which the display panel switches the image light with the timing at which the polarization control unit switches the polarization direction. This will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of operation of the image display device 100 according to an embodiment of the present technology.

[0055] As shown in FIG. 5, first, in step S1, control signals are input to the polarization control unit 5 and the image control unit 6, respectively.

[0056] Next, in step S2, a video signal is input to the image control unit 6. This video signal alternately includes image frames corresponding to the first region and image frames corresponding to the second region. The frame rate is not particularly limited, but a higher frame rate is preferable. For example, the frame rate is preferably 120 fps or higher, more preferably 240 fps or higher, and even more preferably 480 fps or higher.

[0057] Next, in step S3, the image control unit 6 inverts the image frame corresponding to the first region.

[0058] Next, in step S4, the display panel 1 generates image light based on the video signal. At this time, the image control unit 6 synchronizes the timing at which the display panel switches the image light with the timing at which the polarization control unit switches the polarization direction.

[0059] This will be further described with reference to Fig. 6. Fig. 6 is a graph showing an example of the operation of the image display device 100 according to an embodiment of the present technology.

[0060] Fig. 6A is a graph showing an example of the operation of the polarization control unit 5. The horizontal axis represents time, and the vertical axis represents the voltage applied to the polarization control unit 5. As shown in Fig. 6A, periods during which a voltage is applied to the polarization control unit 5 and periods during which no voltage is applied are alternately repeated.

[0061] 6B is a graph showing the polarization direction of the image light emitted by the polarization control unit 5. When a voltage is applied, the polarization control unit 5 emits, for example, P-polarized light. When no voltage is applied, the polarization control unit 5 emits, for example, S-polarized light.

[0062] 6C is a graph showing the types of image light generated by the display panel 1. When the polarization control unit 5 emits P-polarized light, the display panel 1 generates image light corresponding to, for example, central vision. When the polarization control unit 5 emits S-polarized light, the display panel 1 emits image light corresponding to, for example, peripheral vision.

[0063] In this way, the display panel 1 alternately generates image light corresponding to a first region (e.g., peripheral vision) and image light corresponding to a second region (e.g., central vision). At this time, crosstalk may occur when the image light switches between the first and second regions. Therefore, it is preferable that the image control unit 6 turn off the display panel 1 at the timing when the image corresponding to the first region switches between the image corresponding to the second region.

[0064] This will be described with reference to Fig. 7. Fig. 7 is a schematic diagram showing an example of the operation of the image display device 100 according to an embodiment of the present technology.

[0065] 7A is a graph showing an example of the operation of the polarization control unit 5. The polarization control unit 5 alternately switches between P-polarized light and S-polarized light, for example.

[0066] 7B is a diagram showing an example of the operation of the display panel 1. The display panel 1 operates in synchronization with the polarization control unit 5. The display panel 1 alternately generates a first image light (image light corresponding to the first region) L1 emitted as P-polarized light and a second image light (image light corresponding to the second region) L2 emitted as S-polarized light.

[0067] At this time, as shown in Fig. 7A, the polarization direction does not switch instantaneously. As the intensity of the P-polarized light gradually decreases, the intensity of the S-polarized light gradually increases. Therefore, the intensity of the S-polarized light from the polarization control unit 5 may increase while the display panel 1 is still generating the first image light L1. This may cause crosstalk.

[0068] 7C , it is preferable that the image control unit 6 turn off the display panel 1 at the timing when the first image light L1 and the second image light L2 are switched. In this example, a delay time τ is generated between the timing when the polarization control unit 5 emits P-polarized light (see FIG. 7A ) and the timing when the display panel 1 emits the first image light L1 (see FIG. 7B ). By generating the delay time τ for the display panel 1 that is driven at a duty of 20%, the display panel 1 is in an inactive state (a state in which no light is emitted) for 80% of the time.

[0069] The above description of the image display device according to the first embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0070] 2. Second Embodiment of the Present Technology (Example 2 of Image Display Device)] An image display device according to another embodiment of the present technology will be described with reference to Fig. 8. Fig. 8 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0071] 8 , the display panel 1, the polarization control unit 5, and the polarization conversion unit 3 are stacked in the order in which the image light passes. In the first embodiment, the image display device 100 includes two polarization conversion units 3. On the other hand, in the second embodiment, the image display device 100 includes one polarization conversion unit 3.

[0072] In the second embodiment, the optical system 2 includes a geometric phase diffractive lens. This diffractive lens may be, for example, a Pancharatnam Berry phase (PBP) lens. By using the geometric phase diffractive lens, the image display device 100 can be made thinner.

[0073] For example, the display panel 1 generates image light corresponding to a second region (e.g., the central visual field). The polarization control unit 5 converts the polarization direction of this image light into P-polarized light. The polarization conversion unit 3 converts this P-polarized light into right-handed circularly polarized light. The optical system 2 focuses this right-handed circularly polarized light. This allows the viewer to view an image corresponding to the second region. In other words, an image corresponding to the central visual field is displayed in the viewer's central visual field.

[0074] At this time, when this image light is reflected by the reflector 4 or the like, the right-handed circularly polarized light is converted into left-handed circularly polarized light. Since the optical system 2 diverges the left-handed circularly polarized light, an image corresponding to the central visual field is not displayed in the peripheral visual field of the observer.

[0075] Next, the display panel 1 generates image light corresponding to a first region (for example, peripheral vision). The polarization control unit 5 converts the polarization direction of this image light into S-polarized light. The polarization conversion unit 3 converts this S-polarized light into left-handed circularly polarized light. When this image light is reflected by a reflector 4 or the like, the left-handed circularly polarized light is converted into right-handed circularly polarized light. The optical system 2 focuses this right-handed circularly polarized light. This allows the viewer to view an image corresponding to the first region. In other words, an image corresponding to the peripheral vision is displayed in the viewer's peripheral vision.

[0076] On the other hand, since the optical system 2 diverges left-handed circularly polarized light, the image light that reaches the optical system 2 without being reflected by the reflector 4 or the like is diverged by the optical system 2. In other words, an image corresponding to the peripheral visual field is not displayed in the central visual field of the observer.

[0077] The above description of the image display device according to the second embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0078] 3. Third Embodiment of the Present Technology (Example 3 of Image Display Device)] An image display device according to another embodiment of the present technology will be described with reference to Fig. 9. Fig. 9 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0079] 9 , a reflector 4 is disposed between the pupil and the optical system 2, and between the optical system 2 and the polarization control unit 5. A polarization conversion unit 3 is disposed between the optical system 2 and the polarization control unit 5. The optical system 2 has a polarization transmission unit 21 that selectively transmits linearly polarized light, and a lens 22.

[0080] The reflector 4 disposed between the pupil and the optical system 2 and the reflector 4 disposed between the optical system 2 and the polarization controller 5 may be integrally molded or may be separate. In this embodiment, the reflector 4 is integrally molded.

[0081] According to this embodiment, the image light is reflected twice. For example, the image light emitted from the polarization control unit 5 is reflected by the reflector 4 disposed between the optical system 2 and the polarization control unit 5, passes through the optical system 2, and is reflected by the reflector 4 disposed between the pupil and the optical system 2 to be guided to the pupil.

[0082] According to this embodiment, the image light is reflected twice, eliminating the need for image inversion processing corresponding to the peripheral vision, thereby reducing the delay (latency) caused by this inversion processing.

[0083] Furthermore, since the reflector 4 is disposed between the pupil and the optical system 2, the image display device 100 can allow the viewer to view an image with a wider field of view.

[0084] The polarization direction of the image light emitted by the polarization control unit 5 and the polarization direction transmitted by the polarized light transmitting unit 21 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0085] The above description of the image display device according to the third embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0086] 4. Fourth Embodiment of the Present Technology (Example 4 of Image Display Device) An image display device according to another embodiment of the present technology will be described with reference to Fig. 10. Fig. 10 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0087] 10 , a reflector 4 is disposed between the pupil and the optical system 2, and between the optical system 2 and a polarization control unit 5. A display panel 1, a polarization control unit 5, and a polarization conversion unit 3 are layered in the order in which the image light passes. The optical system 2 has a diffractive lens based on a geometric phase.

[0088] The reflector 4 disposed between the pupil and the optical system 2 and the reflector 4 disposed between the optical system 2 and the polarization control unit 5 may be integrally molded or may be separate. In this embodiment, the reflector 4 is separate.

[0089] According to this embodiment, the image light is reflected twice, and the effect is the same as that of the third embodiment, so a description thereof will be omitted.

[0090] The polarization direction of the image light emitted by the polarization control unit 5 and the polarization direction in which the optical system 2 focuses or diverges the light are the same as those in the second embodiment, and therefore a description thereof will be omitted.

[0091] The above description of the image display device according to the fourth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0092] 5. Fifth Embodiment of the Present Technology (Fifth Example of Image Display Device) An image display device according to another embodiment of the present technology will be described with reference to Fig. 11. Fig. 11 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0093] 11 , the reflector 4 is disposed at an angle with respect to the vertical direction of the display panel 1. The optical system 2 has a polarized light transmitting section 21 that selectively transmits linearly polarized light, and a lens 22.

[0094] When an image with a wide field of view is to be viewed by an observer, the diameter of the lens 22 of the optical system 2 tends to be large. On the other hand, in recent years, there has been a trend toward adopting a display panel 1 that is small but has a large number of pixels. In such a case, by arranging the reflector 4 at an angle with respect to the vertical direction of the display panel 1, it is possible to effectively utilize the space within the image display device 100 and make the device more compact.

[0095] When the width of the display panel 1 is s, the width of the reflector 4 is l, the length of the gap between the reflector 4 and the display panel 1 is q, and the tilt angle of the reflector 4 is β, it is preferable to satisfy the following formula (2).

[0096] l・sinβ+s / 2=(l・cosβ+q)・tan(2β)...(2)

[0097] Satisfying this formula improves the peak luminance distribution near the center of the display panel 1. As a result, image light from near the center of the display panel 1 more easily reaches the pupil.

[0098] The polarization direction of the image light emitted by the polarization control unit 5 and the polarization direction transmitted by the polarized light transmitting unit 21 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0099] The above description of the image display device according to the fifth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0100] 6. Sixth Embodiment of the Present Technology (Example 6 of Image Display Device)] An image display device according to another embodiment of the present technology will be described with reference to Fig. 12. Fig. 12 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0101] 12, a display panel 1, a polarization control unit 5, and a polarization conversion unit 3 are stacked in the order in which image light passes. An optical system 2 has a diffractive lens based on a geometric phase.

[0102] The reflector 4 is disposed at an angle with respect to the vertical direction of the display panel 1. The effect is the same as that of the fifth embodiment, and therefore a description thereof will be omitted.

[0103] The polarization direction of the image light emitted by the polarization control unit 5 and the polarization direction in which the optical system 2 focuses or diverges the light are the same as those in the second embodiment, and therefore a description thereof will be omitted.

[0104] The above description of the image display device according to the sixth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0105] 7. Seventh Embodiment of the Present Technology (Seventh Example of Image Display Device) An image display device according to another embodiment of the present technology will be described with reference to Fig. 13. Fig. 13 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0106] As shown in FIG. 13, the display panel 1 and the polarization control unit 5 are stacked in the order in which the image light passes.

[0107] The optical system 2 has a lens 22, a polarized light transmitting section 21, and an anti-reflection section 23. The polarized light transmitting section 21 and the anti-reflection section 23 are stacked together. The anti-reflection section 23 is disposed on the side where image light is incident.

[0108] The optical system 2 transmits a part of the image light and reflects a part of the image light toward the reflector 4. The polarization conversion unit 3 is disposed on the surface of the reflector 4 onto which the image light is incident.

[0109] The polarization direction of the image light emitted by the polarization control unit 5 and the polarization direction transmitted by the polarized light transmitting unit 21 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0110] According to this embodiment, the chief ray is more easily guided to the pupil than in a configuration using a light guide plate.

[0111] The above description of the image display device according to the seventh embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0112] 8. Eighth Embodiment of the Present Technology (Eighth Example of Image Display Device) An image display device according to another embodiment of the present technology will be described with reference to Fig. 14. Fig. 14 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0113] As shown in FIG. 14, the display panel 1 and the polarization control unit 5 are stacked in the order in which the image light passes through.

[0114] The optical system 2 is integrally molded to include the polarization conversion section 3 and the polarization transmission section 21. The optical system 2 may be configured as a prism 24, for example.

[0115] In the prism 24, the image light incident surface and the image light exit surface are free-form surfaces, and the surface on which the polarization conversion unit 3 is disposed is a flat surface.

[0116] The polarization direction of the image light emitted by the polarization control unit 5 and the polarization direction transmitted by the polarized light transmitting unit 21 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0117] According to this embodiment, the number of manufacturing steps is reduced, which makes it possible to improve manufacturing efficiency and reduce manufacturing costs.

[0118] The above description of the image display device according to the eighth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0119] 9. Ninth Embodiment of the Present Technology (Ninth Example of Image Display Device) An image display device according to another embodiment of the present technology will be described with reference to Fig. 15. Fig. 15 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0120] As shown in FIG. 15, the display panel 1 and the polarization control unit 5 are stacked in the order in which the image light passes.

[0121] The optical system 2 includes a polarized light transmitting section 21 and a lens 22. The polarized light transmitting section 21 transmits a part of the image light and reflects a part of the image light toward the reflector 4.

[0122] The reflector 4 may be, for example, an axially symmetric curved mirror. The reflector 4 reflects the image light from the polarization conversion unit 3. The reflector 4 reflects part of the image light toward the optical system 2, and part of the image light toward the pupil. In other words, according to this embodiment, the image light is reflected twice. The effect is the same as in the third embodiment, and therefore a description thereof will be omitted.

[0123] The polarization direction of the image light emitted by the polarization control unit 5 and the polarization direction transmitted by the polarized light transmitting unit 21 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0124] The above description of the image display device according to the ninth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0125] 10. Tenth Embodiment of the Present Technology (Tenth Example of Image Display Device) An image display device according to another embodiment of the present technology will be described with reference to Fig. 16. Fig. 16 is a schematic diagram showing a configuration example of an image display device 100 according to an embodiment of the present technology.

[0126] As shown in Figure 16, an optical element 8 that changes the direction of image light is disposed between the display panel 1 and the reflector 4. This optical element 8 can be, for example, a prism or a diffractive optical element. The prism may be, for example, a V-block prism. The diffractive optical element may be, for example, an optical deflector such as a Pb phase deflector, a hologram, or a grating. The Pb phase deflector is an optical deflector that uses liquid crystal and can be made thinner than a prism.

[0127] A plate-like optical element 81 that transmits image light is also disposed in the optical element 8. The plate-like optical element 81 may be made of glass, for example.

[0128] According to this embodiment, it is possible to make the boundary line between an image corresponding to the central visual field and an image corresponding to the peripheral visual field less noticeable. This will be described with reference to Fig. 17. Fig. 17 is a schematic diagram showing an example configuration of an optical element 8 according to an embodiment of the present technology.

[0129] 17 , a V-block prism is shown as an example of the optical element 8. Image light is incident on this optical element 8 from both the display panel 1 and the reflector 4. The optical element 8 combines the incident image light beams and emits them as a single light beam. With this configuration, it is possible to make the boundary between the image corresponding to the central visual field and the image corresponding to the peripheral visual field less noticeable.

[0130] To make this boundary line less noticeable, the focus position may be adjusted, for example, by defocusing the focus position from the display panel 1 to give the beam spot a certain width.

[0131] The above description of the image display device according to the tenth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[0132] It should be noted that the embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible within the scope of the present technology. The specific numerical values, shapes, materials (including compositions), etc. described in each embodiment are merely examples, and the present technology is not limited to these.

[0133] The present technology can also be configured as follows. [1] An image display device comprising: a display panel that generates image light; an optical system that transmits and guides the image light of a predetermined polarization direction to a viewer's pupil; a reflector that reflects, of the image light from the display panel, image light corresponding to a first region in the viewer's field of view toward the optical system; and a polarization control unit that switches the polarization direction of the image light, wherein the polarization control unit alternately switches the polarization direction of the image light corresponding to the first region and the polarization direction of image light corresponding to a second region in the viewer's field of view that is different from the first region. [2] The image display device according to [1], further comprising a polarization conversion unit that converts the polarization direction of the image light from the display panel. [3] The image display device according to [2], wherein the polarization conversion unit is disposed outside the display panel and in a vertical direction of the display panel, and the polarization conversion unit and the reflector are stacked in order from the side where the image light is incident. [4] The image display device according to any one of [1] to [3], wherein the following mathematical formula (1) is satisfied, where s is the width of the display panel, l is the width of the reflector, q is the length of the gap between the reflector and the display panel, and α is the angle formed between the reflector and a line segment connecting the center of the display panel and the end of the reflector on the optical system side. s / 2=(l+q)·tan(α) (1) [5] The image display device according to any one of [1] to [4], wherein the optical system includes a polarization transmission unit that selectively transmits linearly polarized light, and a lens. [6] The image display device according to any one of [2] to [5], wherein the display panel, the polarization control unit, and the polarization conversion unit are stacked in the order in which the image light passes through. [7] The image display device according to any one of [1] to [6], wherein the optical system includes a diffractive lens based on a geometric phase. [8] The image display device according to any one of [1] to [7], wherein the reflector is disposed between the pupil and the optical system, and between the optical system and the polarization control unit.[9] The image display device according to [8], wherein the optical system has a polarization transmission unit that selectively transmits linearly polarized light and a lens, and a polarization conversion unit that converts the polarization direction of image light from the display panel is disposed between the optical system and the polarization control unit.

[10] The image display device according to any one of [8] or [9], wherein the optical system has a diffractive lens based on a geometric phase.

[11] The image display device according to any one of [1] to

[10] , wherein the reflector is disposed at an angle with respect to the vertical direction of the display panel.

[12] The image display device according to

[11] , wherein the following mathematical formula (2) is satisfied, where s is the width of the display panel, l is the width of the reflector, q is the length of the gap between the reflector and the display panel, and β is the inclination angle of the reflector. l sin β + s / 2 = (l cos β + q) tan(2β) (2)

[13] The image display device according to any one of [1] to

[12] , wherein the optical system transmits a portion of the image light and reflects a portion of the image light toward the reflector.

[14] The image display device according to any one of [1] to

[13] , wherein the optical system is integrally molded to include a polarization conversion unit that converts the polarization direction of the image light from the display panel and a polarization transmission unit that selectively transmits linearly polarized light.

[15] The image display device according to any one of [1] to

[14] , wherein the optical system transmits a portion of the image light and reflects a portion of the image light toward the reflector, and the reflector reflects a portion of the image light toward the optical system and reflects a portion of the image light toward the pupil.

[16] The image display device according to any one of [1] to

[15] , wherein an optical element that changes the direction of the image light is disposed between the display panel and the reflector.

[17] The image display device according to any one of [1] to

[16] , further comprising an image control unit that synchronizes a timing at which the display panel switches the image light with a timing at which the polarization control unit switches the polarization direction.

[18] The image display device according to

[17] , wherein the image control unit inverts the image corresponding to the first region.

[19] The image display device according to

[17] or

[18] , wherein the image control unit turns off the display panel at a timing when an image corresponding to the first region and an image corresponding to the second region are switched.

[20] The image display device according to any one of [1] to

[19] , wherein the first region is a peripheral visual field, and the second region is a central visual field.

[0134] REFERENCE SIGNS LIST 100 Image display device 1 Display panel 2 Optical system 21 Polarized light transmitting section 22 Lens 23 Anti-reflection section 3 Polarized light converting section 4 Reflector 5 Polarization control section 51 Liquid crystal 52 Transparent electrode 53 Polarizer 6 Image control section 7 Power supply 8 Optical element

Claims

1. An image display device comprising: a display panel that generates image light; an optical system that transmits image light having a predetermined polarization direction and guides it to the observer's pupil; a reflector that reflects, toward the optical system, image light corresponding to a first region in the observer's field of view among the image light from the display panel; and a polarization control unit that switches the polarization direction of the image light, wherein the polarization control unit alternately switches the polarization direction of the image light corresponding to the first region and the polarization direction of the image light corresponding to a second region different from the first region in the observer's field of view.

2. The image display device according to claim 1, further comprising a polarization conversion unit that converts the polarization direction of the image light from the display panel.

3. The image display device according to claim 2, wherein the polarization conversion unit is disposed outside the display panel and in the vertical direction of the display panel, and the polarization conversion unit and the reflector are laminated in order from the side where the image light is incident.

4. The image display device according to claim 1, wherein when the width of the display panel is s, the width of the reflector is l, the length of the gap between the reflector and the display panel is q, and the angle formed by the line segment connecting the center of the display panel and the end of the reflector on the optical system side and the reflector is α, the following formula (1) is satisfied. s / 2 = (l + q) · tan(α) ··· (1) 5. The image display device according to claim 1, wherein the optical system has a polarization transmission part that selectively transmits linearly polarized light and a lens.

6. The image display device according to claim 2, wherein the display panel, the polarization control unit, and the polarization conversion unit are laminated in the order in which the image light passes.

7. The image display device according to claim 1, wherein the optical system has a diffraction lens based on geometric phase.

8. The image display device according to claim 1, wherein the reflector is disposed between the pupil and the optical system and between the optical system and the polarization control unit.

9. The image display device according to claim 8, wherein the optical system has a polarization transmission part that selectively transmits linearly polarized light and a lens, and a polarization conversion unit that converts the polarization direction of the image light from the display panel is disposed between the optical system and the polarization control unit.

10. The image display device according to claim 8, wherein the optical system has a diffraction lens based on geometric phase.

11. The image display device according to claim 1, wherein the reflector is disposed at an angle with respect to the vertical direction of the display panel.

12. The image display device according to claim 11, wherein when the width of the display panel is s, the width of the reflector is l, the length of the gap between the reflector and the display panel is q, and the tilt angle of the reflector is β, the following formula (2) is satisfied. l·sinβ + s / 2 = (l·cosβ + q)·tan(2β) ··· (2) 13. The image display device according to claim 1, wherein the optical system transmits a part of the image light and reflects a part of the image light toward the reflector.

14. The image display device according to claim 1, wherein the optical system includes a polarization conversion unit that converts the polarization direction of the image light from the display panel and a polarization transmission unit that selectively transmits linearly polarized light, and is integrally formed.

15. The image display device according to claim 1, wherein the optical system transmits a part of the image light and reflects a part of the image light toward the reflector, the reflector reflects a part of the image light toward the optical system, and reflects a part of the image light toward the pupil.

16. The image display device according to claim 1, wherein an optical element for changing the direction of the image light is disposed between the display panel and the reflector.

17. The image display device according to claim 1, further comprising an image control unit that synchronizes the timing at which the display panel switches the image light and the timing at which the polarization control unit switches the polarization direction.

18. The image display device according to claim 17, wherein the image control unit inverts the image corresponding to the first region.

19. The image display device according to claim 17, wherein the image control unit turns off the display panel at the timing when the image corresponding to the first region and the image corresponding to the second region are switched.

20. The image display device according to claim 1, wherein the first region is a peripheral visual field and the second region is a central visual field.

Images