Display device

Abstract

Provided is a display device capable of stably displaying a wide viewing angle image having high image quality while reducing size and crosstalk. A display device according to the present technology includes: an image light generation system that generates image light; and a light guide system that guides the image light generated by the image light generation system to an eyeball of a user, in which the light guide system includes a diffraction unit having polarization selectivity on which at least light having a corresponding polarization state of the image light is incident, and the diffraction unit diffracts the incident light with the corresponding polarization state towards the eyeball. A display device according to the present technology can provide a display device capable of stably displaying a wide viewing angle image having high image quality while reducing size and crosstalk.

Description

Technical Field

[0001] A technology according to the present disclosure (hereinafter also referred to as “the present technology”) relates to a display device. Background Art

[0002] Conventionally, a known display device (see, for example, Patent Document 1) uses image light including multiple beams of light to illuminate the user's eyeball via a diffraction unit to display a wide-viewing angle image. However, the display device has room for improvement in terms of displaying a wide-viewing angle image and reducing size and crosstalk.

[0003] Therefore, a display device has been proposed that displays an image by irradiating a user's eyeball with image light including multiple beams of light of different wavelengths via a diffraction unit having wavelength selectivity (for example, see Patent Document 2). The display device can display a wide viewing angle image while reducing size and crosstalk.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-54978

[0007] Patent document 2: WO 2021 / 220638 A Summary of the invention

[0008] Problems to be solved by the present invention

[0009] In the display device (for example, refer to Patent Document 2), the wavelength band in which the diffraction unit can have a desired diffraction rate is very narrow, and the wavelength of light incident on the diffraction unit may deviate from the wavelength band due to a change in the emission wavelength of the light source caused by, for example, temperature change, so that the desired diffraction rate cannot be obtained. Therefore, the display device has room for improvement in terms of stably displaying a wide-viewing angle image with high image quality.

[0010] Therefore, a main object of the present technical content is to provide a display device that can stably display a wide-viewing angle image with high image quality while reducing the size and crosstalk.

[0011] Solution to the problem

[0012] The present technology provides a display device, comprising:

[0013] an image light generating system that generates image light; and

[0014] a light guiding system, the light guiding system guiding the image light generated by the image light generating system to the eyeball of the user; wherein

[0015] The light guiding system comprises a diffraction unit with polarization selectivity,

[0016] At least light having a corresponding polarization state in the image light is incident on the diffraction unit, and

[0017] The diffraction unit diffracts the incident light with the corresponding polarization state toward the eyeball.

[0018] The light guiding system may comprise a plurality of said diffraction units.

[0019] At least two diffraction units among the plurality of diffraction units may correspond to different polarization states.

[0020] At least two diffraction units among the plurality of diffraction units may correspond to the same polarization state.

[0021] The plurality of diffraction units may include at least two diffraction units corresponding to different polarization states and at least two diffraction units corresponding to the same polarization state.

[0022] Each of the plurality of diffraction units can make light with a corresponding polarization state incident on the eyeball from directions different from each other.

[0023] The light guide system may include a light guide plate that faces the eyeball and totally reflects and guides the incident image light generated by the image light generating system, and a plurality of the diffraction units may be disposed on the light guide plate.

[0024] The plurality of diffraction units may include at least one diffraction unit disposed on a surface of the light guide plate on an eyeball side and / or at least one diffraction unit disposed on a surface of the light guide plate on a side opposite to the eyeball side.

[0025] The light guide system may include a relay optical system that causes the image light generated by the image light generating system to be incident on the light guide plate at an incident angle such that the image light is totally reflected in the light guide plate.

[0026] The light having the corresponding polarization state may be circularly polarized light, and the diffraction unit may have circular polarization selectivity.

[0027] The light with the corresponding polarization state may be circularly polarized light, the multiple diffraction units may include a first diffraction unit and a second diffraction unit, at least a first circularly polarized light in the image light is incident on the first diffraction unit, at least a second circularly polarized light in the image light is incident on the second diffraction unit, the polarization direction of the second circularly polarized light is different from the polarization direction of the first circularly polarized light, the first diffraction unit has polarization selectivity for the first circularly polarized light, and the second diffraction unit has polarization selectivity for the second circularly polarized light.

[0028] The first diffraction unit and the second diffraction unit may each have a cholesteric liquid crystal element.

[0029] The rotation directions of the liquid crystal molecules in the cholesteric liquid crystal elements of the first diffraction unit and the second diffraction unit are opposite.

[0030] In the cholesteric liquid crystal elements of the first diffraction unit and the second diffraction unit, the alignment direction of the liquid crystal molecules may be inclined with respect to the thickness direction of the cholesteric liquid crystal element.

[0031] The light guiding system may include at least one phase difference film arranged on an optical path of the image light.

[0032] The diffraction unit may be a diffraction unit in which a plurality of diffraction patterns corresponding to different polarization states are formed in various ways or a diffraction unit in which a plurality of layers in which diffraction patterns corresponding to different polarization states are formed are stacked.

[0033] The image light generating system may include a light source unit including a light source and a light deflector that deflects light from the light source unit.

[0034] The image light generating system may include another diffraction unit that is arranged on an optical path of the image light between the light source unit and the light deflector and corrects chromatic aberration of the diffraction unit.

[0035] The image light generating system may include an optical element arranged on an optical path of the image light between the light source unit and the light deflector, and an optical element control unit that controls the optical element.

[0036] The multiple beams of light with different polarization states in the image light can be incident on the corresponding multiple diffraction units in different time periods. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1A and FIG. 1B are schematic diagrams for explaining problems in the display devices of Comparative Examples 1 and 2, respectively.

[0038] FIG. 2A and FIG. 2B are schematic diagrams for explaining a problem in the display device of Comparative Example 3. FIG.

[0039] 3 is a graph showing a relationship between a viewing angle of a displayed image and a thickness of a light guide plate with respect to a light guide plate using a general diffraction unit and a light guide plate using a diffraction unit having selectivity.

[0040] Fig. 4A is a schematic configuration diagram for explaining the principle of the display device of the present technology. Fig. 4B shows graphs respectively showing the relationship between the wavelength of polarized light and the diffraction rate of the corresponding diffraction unit in the display device of the present technology.

[0041] Fig. 5A is a schematic configuration diagram showing the viewing distance of the display device of the present technology. Fig. 5B is a graph showing the relationship between the viewing distance and the viewing angle of the displayed image in relation to the display device of the present technology and a display device using a general light guide plate.

[0042] FIG. 6 is a schematic diagram illustrating a configuration of a display device according to a first embodiment of the present technology.

[0043] FIG. 7 is a schematic diagram showing a configuration example of a light source unit in the display device in FIG. 6 .

[0044] FIG. 8 is a schematic diagram illustrating a configuration of a display device according to Example 1 of a second embodiment of the present technology.

[0045] 9A and 9B are a side view and a plan view of Configuration Example 1 of the diffraction unit, respectively.

[0046] 10A and 10B are schematic diagrams illustrating circular polarization selectivity of Configuration Example 1 of the diffraction unit.

[0047] 11A and 11B are views showing liquid crystal molecule arrays in the first diffraction unit and the second diffraction unit, respectively.

[0048] 12A and 12B are a side view and a plan view of Configuration Example 2 of the diffraction unit, respectively.

[0049] 13A and 13B are schematic diagrams illustrating polarization selectivity of Configuration Example 2 of the diffraction unit.

[0050] 14A to 14C are views showing configuration examples 1 to 3 of the diffraction unit, respectively.

[0051] FIG. 15 is a schematic diagram illustrating a configuration of a display device according to Example 2 of the second embodiment of the present technology.

[0052] FIG. 16 is a schematic diagram illustrating a configuration of a display device according to Example 3 of the second embodiment of the present technology.

[0053] FIG. 17 is a schematic diagram illustrating a configuration of a display device according to Example 4 of the second embodiment of the present technology.

[0054] FIG. 18 is a schematic diagram illustrating a configuration of a display device according to Example 5 of the second embodiment of the present technology.

[0055] FIG. 19 is a schematic diagram illustrating a configuration of a display device according to Example 6 of the second embodiment of the present technology.

[0056] FIG. 20 is a schematic diagram illustrating a configuration of a display device according to a third embodiment of the present technology.

[0057] FIG. 21 is a schematic diagram illustrating a configuration of a display device according to a fourth embodiment of the present technology.

[0058] FIG. 22 is a block diagram illustrating functions of a display device according to a fourth embodiment of the present technology.

[0059] FIG. 23 is a schematic diagram illustrating an operation (Part 1) of the display device according to the fourth embodiment of the present technology.

[0060] FIG. 24 is a schematic diagram illustrating an operation (Part 2) of the display device according to the fourth embodiment of the present technology.

[0061] FIG. 25 is a schematic diagram illustrating a configuration of a display device according to a fifth embodiment of the present technology.

[0062] FIG. 26 is a schematic diagram showing a configuration example of a light source unit in the display device in FIG. 25 .

[0063] Fig. 27A is a schematic diagram showing an example in which diffraction elements are densely provided on both surfaces of a light guide plate. Fig. 27B is a schematic diagram showing an example in which diffraction elements are provided on one surface of a light guide plate.

[0064] FIG. 28 is a schematic diagram illustrating a configuration of a display device according to a sixth embodiment of the present technology.

[0065] Fig. 29A is a schematic diagram showing a configuration of a display device according to Example 1 of a seventh embodiment of the present technology. Fig. 29B is a schematic diagram for explaining a display method of the display device in Fig. 29A.

[0066] FIG. 30 is a schematic diagram showing a configuration example of a light source unit in the display device in A of FIG. 29 .

[0067] Fig. 31A is a schematic diagram showing a configuration of a display device according to Example 2 of a seventh embodiment of the present technology. Fig. 31B is a schematic diagram for explaining a display method of the display device in Fig. 31A.

[0068] FIG. 32 is a schematic diagram showing a configuration example of a light source unit in the display device in A of FIG. 31 .

[0069] Fig. 33A is a schematic diagram showing a configuration of a display device according to Example 3 of a seventh embodiment of the present technology. Fig. 33B is a schematic diagram for explaining a display method of the display device in Fig. 33A.

[0070] FIG. 34 is a schematic diagram showing the configuration of Modification 1 of the relay optical system.

[0071] FIG. 35 is a schematic diagram showing the configuration of Modification 2 of the relay optical system. DETAILED DESCRIPTION

[0072] Hereinafter, preferred embodiments of the present technology will be described in detail with reference to the accompanying drawings. Note that in this specification and the accompanying drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and repeated descriptions are omitted. The embodiments to be described below provide representative embodiments of the present technology, but the scope of the present technology should not be narrowly interpreted based on these embodiments. In this specification, even in the case where the display device of the present technology is described as exhibiting multiple effects, the display device of the present technology only needs to exhibit at least one effect. The effects described in this specification are merely examples and are not restrictive, and other effects may be exerted.

[0073] Furthermore, the description will be given in the following order.

[0074] 0. Introduction

[0075] 1. Display device according to the first embodiment of the present technology

[0076] 2. Display device according to the second embodiment of the present technology

[0077] 3. Display device according to the third embodiment of the present technology

[0078] 4. Display device according to the fourth embodiment of the present technology

[0079] 5. Display device according to the fifth embodiment of the present technology

[0080] 6. Display device according to the sixth embodiment of the present technology

[0081] 7. Display device according to the seventh embodiment of the present technology

[0082] 8. Modifications of the present technology

[0083] <0. Introduction>

[0084] (Problems in the comparative example)

[0085] FIG. 1A and FIG. 1B are schematic diagrams for explaining the problems in the display devices of Comparative Example 1 and Comparative Example 2, respectively. In the display device of Comparative Example 1 shown in FIG. 1A , the image light is totally reflected and propagated in the light guide plate, and is diffracted toward the eyeball EB through the diffraction unit to form a wide-angle image. However, in this display device, if the light deflection width in the light guide plate is small (for example, if the light guide plate is thin), light with the same information is incident on multiple different positions of the diffraction unit (is incident on the diffraction unit multiple times), and the eyeball is illuminated by the light at different viewing angles, which causes crosstalk. Therefore, in the display device of Comparative Example 2 shown in FIG. 1B , crosstalk can be suppressed by increasing the light deflection width (for example, thickening the light guide plate), but in this case, it will result in an increase in size.

[0086] FIG. 2A and FIG. 2B are schematic diagrams for explaining the problem in the display device of Comparative Example 3. The mark DE on the vertical axis in FIG. 2B represents the diffraction rate. The display device of Comparative Example 3 shown in FIG. 2A totally reflects and propagates image light including multiple beams of light (having different wavelengths, such as wavelengths λ1 and λ2 of similar colors) in a thinner light guide plate, and diffracts the image light toward the eyeball EB through the first and second diffraction units having wavelength selectivity, thereby displaying a wide-viewing angle image. In the display device of Comparative Example 3, the first diffraction unit has wavelength selectivity for λ1, and the second diffraction unit has wavelength selectivity for λ2. In this case, the left half viewing angle of the entire viewing angle can be formed by the light of λ1, the right half viewing angle can be formed by the light of λ2, and even if the light deflection width in the light guide plate is small (for example, even if the light guide plate is thin), light with the same information can be incident on one diffraction unit at a time. As a result, the display device of Comparative Example 3 can display a wide-viewing angle image while reducing crosstalk and size (see FIG. 3). To add more information, Fig. 3 is a graph showing the relationship between the viewing angle of a displayed image and the thickness of the light guide plate in relation to a light guide plate using a general diffraction unit and a light guide plate using a diffraction unit having selectivity. As shown in Fig. 3, in a light guide plate using a diffraction unit having selectivity (e.g., wavelength selectivity), an image of the same viewing angle can be displayed using a thinner plate thickness (e.g., approximately half the plate thickness) compared to a general light guide plate.

[0087] However, in the display device of Comparative Example 3, the wavelength band in which each diffraction unit having wavelength selectivity can make the diffraction unit have a desired diffraction rate is narrow (see B of FIG. 2 ), and, for example, a change in the emission wavelength of the light source caused by temperature change or the like may cause the wavelength of light to deviate from the wavelength band, and the desired diffraction rate cannot be obtained. Therefore, in the display device of Comparative Example 3, there is a possibility that a wide-viewing angle image with high image quality cannot be stably displayed.

[0088] Therefore, as a result of intensive studies, the inventors have developed a display device of the present technical content, which is capable of stably displaying a wide-viewing angle image with high image quality while reducing the size and crosstalk.

[0089] (Principle of the display device of the present technology)

[0090] Fig. 4A is a schematic configuration diagram for explaining the principle of the display device according to the present technical content. Fig. 4B shows a graph showing the relationship between the wavelength of polarized light and the diffraction rate of the corresponding diffraction unit in the display device according to the present technical content. The mark DE on the vertical axis in Fig. 4B represents the diffraction rate.

[0091] As an example, the display device of the present technical content shown in A of FIG. 4 totally reflects and propagates image light including multiple beams of light (having different polarization states, such as polarized light 1 and polarized light 2) in a thinner light guide plate, and diffracts the image light to the eyeball EB through the first and second diffraction units having polarization selectivity, thereby displaying a wide-viewing angle image. In the display device of the present technical content, the first diffraction unit has polarization selectivity for polarized light 1, and the second diffraction unit has polarization selectivity for polarized light 2. In this case, the left half of the viewing angle of the entire viewing angle can be formed by polarized light 1, and the right half of the viewing angle can be formed by polarized light 2, and even if the light deflection width in the light guide plate is small (for example, even if the light guide plate is thin), light with the same information can be incident on one diffraction unit at a time. In addition, in the display device of the present technical content, as shown in B of FIG. 4, the wavelength band in each diffraction unit that enables the diffraction unit to have a desired diffraction rate is wide, and has high robustness to wavelength changes of light. That is, the display device of the present technical content can stably display high-quality images without being affected too much by changes in the wavelength of light. Therefore, the display device of the present technical content can display a wide-viewing angle image while reducing crosstalk and size.

[0092] FIG5A is a schematic configuration diagram showing the viewing distance of the display device of the present technology. FIG5B is a graph showing the relationship between the viewing distance and the viewing angle of the displayed image in relation to the display device of the present technology and the display device using a light guide plate having a general diffraction unit. As shown in FIG5A and FIG5B, in the display device of the present technology, since a diffraction unit having selectivity (e.g., polarization selectivity) is used, an image having a wider viewing angle can be displayed at the same viewing distance compared to a light guide plate having a general diffraction unit.

[0093] Hereinafter, some embodiments of the display device of the present technical content will be described in detail.

[0094] <1. Display device according to first embodiment of the present technology>

[0095] A display device 10 according to a first embodiment of the present technical content will be described with reference to the accompanying drawings. For example, the display device 10 is used to provide augmented reality (AR), virtual reality (VR), etc. to a user. Hereinafter, for convenience, in each of the drawings, the description is given assuming that the left side of the paper is the left and the right side of the paper is the right.

[0096] <<Display device configuration>>

[0097] 6 is a schematic diagram showing the configuration of a display device 10 according to a first embodiment of the present technical content. For example, the display device 10 is a head-mounted display (HMD) used by being worn on the head of a user. For example, an HMD is also referred to as glasses. As an example, as shown in FIG6 , the display device 10 includes an image light generating system 100-1 and a light guiding system 200-1 that guides the image light IL generated by the image light generating system 100-1 to the user's eyeball EB. The display device 10 may also include a control system 400. As an example, the image light generating system 100-1 and the light guiding system 200-1 are integrally arranged in the same supporting structure (e.g., a glasses frame). The control system 400 may be integrated in the supporting structure or may be separately arranged. In the following, a description is given assuming that an exemplary supporting structure (i.e., a glasses frame) is mounted on the head of a user.

[0098] [Image light generation system]

[0099] As an example, the image light generating system 100 - 1 generates image light IL including a plurality of lights (polarized lights) having different polarization states. As an example, the image light generating system 100 - 1 includes a light source unit 110 - 1 and an emission optical system 120 - 1 .

[0100] (Light source unit)

[0101] Fig. 7 is a schematic diagram showing a configuration example of the light source unit 110-1 in the display device 10. As shown in Fig. 7, the light source unit 110-1 includes, as an example, a first light source 110a1 and a second light source 110a2, a light source driving circuit 110b driving each light source, and a light synthesis element 110c synthesizing light from each light source.

[0102] The first light source 110a1 and the second light source 110a2 are arranged so that the optical paths of the emitted light cross each other. The first light source 110a1 is a polarized light source that emits a first polarized light PL1. The second light source 110a2 is a polarized light source that emits a second polarized light PL2. The first polarized light PL1 and the second polarized light PL2 have different polarization states (e.g., polarization directions). Preferably, each light source is a laser light source. Examples of laser light sources include semiconductor lasers such as laser diodes (LDs) (edge ​​emitting lasers), vertical cavity surface emitting lasers (VCSELs) (surface emitting lasers), and the like.

[0103] The first polarized light PL1 may be monochromatic light (i.e., light of a single wavelength) or may be light obtained by combining lights of multiple wavelengths (i.e., colored light). The second polarized light PL2 may be monochromatic light (i.e., light of a single wavelength) or may be light obtained by combining lights of multiple wavelengths (i.e., colored light).

[0104] The light source driving circuit 110b drives each light source based on modulation data, which will be described later, transmitted from the control system 400. The light source driving circuit includes circuit elements such as transistors and capacitors.

[0105] The light synthesis element 110c is arranged at the intersection of the optical paths of the first polarized light PL1 and the second polarized light PL2 from the first light source 110a1 and the second light source 110a2. The light synthesis element 110c is a beam splitter (e.g., a one-way mirror) that reflects one (e.g., PL1) of the incident first polarized light PL1 and the second polarized light PL2 and transmits the other (e.g., PL2). The synthesized light obtained by synthesizing the first polarized light PL1 and the second polarized light PL2 by the light synthesis element 110c is the image light IL emitted from the light source unit 110-1. That is, the image light IL includes the first polarized light PL1 and the second polarized light PL2.

[0106] (Transmitting optical system)

[0107] 6 , the emission optical system 120 - 1 emits the image light IL from the light source unit 110 - 1 as image light for each viewing angle (eg, image lights IL1 , IL2 , and IL3 ). The emission optical system 120 - 1 includes an optical element 120 a and a light deflector 120 b .

[0108] The optical element 120a is, for example, a lens or a reflector, etc. The optical element 120a converts the image light IL emitted by the light source unit 110-1 into substantially parallel light, convergent light, weakly divergent light, etc., and guides the light to the light deflector 120b. Note that the optical element 120a is not essential and may be omitted in some cases.

[0109] The light deflector 120b is arranged on the optical path of the image light IL emitted from the light source unit 110-1 and passing through the optical element 120a. The light deflector 120b deflects the incident image light IL to generate image light (e.g., IL1, IL2, and IL3) for each viewing angle. The light deflector 120b includes a movable mirror movable around two axes, such as a MEMS mirror, a current mirror, a polygonal mirror, etc. Note that the light deflector 120b may include a first movable mirror movable around one axis and a second movable mirror movable around another axis. The light deflector 120b is controlled by the control system 400. The control system 400 controls the light deflector 120b in synchronization with the control of each light source.

[0110] [Light guide system]

[0111] As an example, the light guide system 200 - 1 includes a light guide plate 210 , a relay optical system 220 , and a plurality of diffraction units 230 (eg, 230 - 1 and 230 - 2 ).

[0112] (Light guide plate)

[0113] The light guide plate 210 faces the eyeball EB. As an example, the image light generating system 100-1 is arranged on the side of the eyeball EB relative to the light guide plate 210. The light guide plate 210 totally reflects and guides the image light IL generated by the image light generating system 100-1 and incident via the relay optical system 220. The light guide plate 210 includes, for example, a transparent, translucent or opaque glass plate or resin plate. The light guide plate 210 may be a type suitable for being assembled into the above-mentioned support structure (i.e., a glasses frame) (lens type) or a type externally attached to the glasses frame (combination component type).

[0114] For example, in the case of providing augmented reality (AR) to the user, a transparent or translucent glass plate is used as the light guide plate 210. For example, in the case of providing virtual reality (VR) to the user, an opaque glass plate is used as the light guide plate 210.

[0115] For example, the thickness of the light guide plate 210 is preferably 2 mm to 5 mm, more preferably 2.5 mm to 4.5 mm, and still more preferably 3 mm to 4 mm. Here, the thickness of the light guide plate 210 is set to 3.1 mm, for example.

[0116] The image light IL entering the light guide plate 210 via the relay optical system 220 propagates by repeating total reflection in the light guide plate 210. That is, the image light IL propagates in the light guide plate 210 in a zigzag shape.

[0117] (Relay optical system)

[0118] As an example, the relay optical system 220 includes a turning mirror 220a that turns the image light IL emitted from the image light generating system 100-1 and transmitted through one end (left end) of the light guide plate 210 toward the light guide plate 210. The position and posture of the turning mirror 220a relative to the light guide plate 210 are set so that the incident image light IL enters the light guide plate 210 at an incident angle such that the image light IL is totally reflected by the light guide plate 210. As an example, the turning mirror 220a is provided integrally with the light guide plate 210.

[0119] (Diffraction unit)

[0120] The light guide system 200-1 includes a plurality of diffraction units 230 (e.g., a first diffraction unit 230-1 and a second diffraction unit 230-2). At least light having a corresponding polarization state in the image light IL is incident on each diffraction unit 230. Each diffraction unit 230 diffracts the incident light having a corresponding polarization state toward the eyeball EB. As an example, the first diffraction unit 230-1 and the second diffraction unit 230-2 are disposed at the other end (the right end, the end facing the eyeball EB) of the light guide plate 210. The first diffraction unit 230-1 and the second diffraction unit 230-2 preferably have polarization selectivity for light having polarization states different from each other. For example, a holographic optical element (HOE), a diffraction optical element (DOE), a metamaterial, etc. may be used as each diffraction unit 230. For example, each diffraction unit 230 may be formed by processing the surface of the light guide plate 210, or each diffraction unit 230 may be attached to the surface of the light guide plate 210.

[0121] At least two (e.g., all) of the plurality of diffraction units 230 correspond to different polarization states among the polarization states of the plurality of light beams. Specifically, the first diffraction unit 230-1 has a desired (high) diffraction rate for the first polarized light PL1, and has a small diffraction rate or no diffraction rate for the second polarized light PL2. The second diffraction unit 230-2 has a desired (high) diffraction rate for the second polarized light PL2, and has a small diffraction rate or no diffraction rate for the first polarized light PL1. Here, the sizes of the diffraction units 230 are the same, but may also be different.

[0122] Each of the multiple diffraction units 230 can make the light of the corresponding polarization state incident on the eyeball from different directions from each other. That is, the multiple diffraction units 230 make the incident image light IL incident on the eyeball EB with a wide viewing angle. Specifically, the first diffraction unit 230-1 and the second diffraction unit 230-2 are arranged separately from each other at least in the in-plane direction of the light guide plate 210 (specifically, the propagation direction (left-right direction) of the image light IL in the light guide plate 210). In addition, as an example, the first diffraction unit 230-1 is set at a position corresponding to the total reflection position of the image light IL on the surface 210a on the eyeball EB side of the light guide plate 210, and the second diffraction unit 230-2 is set at a position corresponding to the total reflection position of the image light IL on the surface 210b on the side opposite to the eyeball EB side of the light guide plate 210. Here, the first diffraction unit 230-1 and the second diffraction unit 230-2 are set at positions on the light guide plate 210 corresponding to the total reflection position where the image light IL is continuously incident. As an example, positions of a right end of the first diffraction unit 230 - 1 and a left end of the second diffraction unit 230 - 2 in the in-plane direction of the light guide plate 210 substantially coincide with each other.

[0123] At least a portion of the image light IL propagating from the left side to the right side in the light guide plate 210 is incident on the first diffraction unit 230-1 and the second diffraction unit 230-2 in sequence. Most of the first polarized light PL1 in the image light IL incident on the first diffraction unit 230-1 is selectively diffracted by the first diffraction unit 230-1 and incident on the eyeball EB, and the remaining portion of the light including the second polarized light PL2 is totally reflected by the light guide plate 210 toward the second diffraction unit 230-2. Most of the second polarized light PL2 in the image light IL incident on the second diffraction unit 230-2 is selectively diffracted by the second diffraction unit 230-2 and incident on the eyeball EB.

[0124] In each diffraction unit 230, the diffraction power for diffracting the light having the corresponding polarization state is distributed in the in-plane direction. The diffraction direction of each diffraction unit 230 for the light having the corresponding polarization state is a direction that does not satisfy the total reflection condition in the light guide plate 210. Therefore, the light having the corresponding polarization state diffracted by each diffraction unit 230 is not totally reflected by the light guide plate 210, but is extracted to the outside of the light guide plate 210.

[0125] For example, the light diffracted at the left end of the first diffraction unit 230-1 is extracted to the outside of the light guide plate 210 to form the leftmost viewing angle of the entire viewing angle. For example, the light diffracted at the right end of the first diffraction unit 230-1 is extracted to the outside of the light guide plate 210 to form the central viewing angle of the entire viewing angle. For example, the light diffracted at the left end of the second diffraction unit 230-2 is extracted to the outside of the light guide plate 210 to form the central viewing angle of the entire viewing angle. The light diffracted at the right end of the second diffraction unit 230-2 is extracted to the outside of the light guide plate 210 to form the rightmost viewing angle of the entire viewing angle.

[0126] That is, the first diffraction unit 230-1 forms light of each angle of view in the left half of the entire angle of view of the image light IL illuminating the eyeball EB, and the second diffraction unit 230-2 forms light of each angle of view in the right half of the entire angle of view of the image light IL illuminating the eyeball EB.

[0127] The diffraction power distribution is set so that the first diffraction unit 230 - 1 and the second diffraction unit 230 - 2 respectively diffract a plurality of lights incident at different positions in the image light IL toward the same position P (focus P) on the eyeball EB.

[0128] (Control System)

[0129] The control system 400 controls the entire display device 10 as a whole. The control system 400 is implemented by hardware such as a CPU, a chipset, etc. The control system 400 generates modulation data based on image data input from an external device or input via a network, and sends the modulation data to the light source driving circuit 110b (see FIG. 7 ).

[0130] <<Operation of display device>>

[0131] Hereinafter, the operation of the display device 10 of the first embodiment of the present technical content will be described. Here, as an example, the case where the diffraction rate of each diffraction unit 230 for the light of the corresponding polarization state is 100% will be described. First, the same operation for each image light IL will be described. The image light IL (three image lights IL1, IL2 and IL3 are shown in FIG6 ) emitted from the image light generating system 100-1 enters the light guide plate 210 via the relay optical system 220 to meet the total reflection condition. The image light IL propagated by repeated total reflection in the light guide plate 210 is incident on the first diffraction unit 230-1. The first polarized light PL1 included in the image light IL incident on the first diffraction unit 230-1 is diffracted by the first diffraction unit 230-1 toward the position P on the eyeball EB, and the second polarized light PL2 is totally reflected by the light guide plate 210 toward the second diffraction unit 230-2. The second polarized light PL2 incident on the second diffraction unit 230 - 2 is diffracted by the second diffraction unit 230 - 2 toward the position P on the eyeball EB.

[0132] Next, the operation of each image light IL1 to IL3 will be described. The image light IL1 emitted from the image light generating system 100-1 and forming the left side perspective of the entire perspective enters the light guide plate 210 via the relay optical system 220 to satisfy the total reflection condition. The image light IL1 propagated by repeated total reflection in the light guide plate 210 is incident on the left end of the first diffraction unit 230-1. Among the image light IL1 incident on the left end of the first diffraction unit 230-1, the image light IL1-1 including the first polarized light PL1 is diffracted by the first diffraction unit 230-1 toward the position P on the eyeball EB so as to form the left side perspective of the entire perspective, and the image light IL1-2 including the second polarized light PL2 is totally reflected by the light guide plate 210 toward the left end of the second diffraction unit 230-2. The image light IL1-2 incident on the left end of the second diffraction unit 230-2 is diffracted toward the position P on the eyeball EB so as to form the center perspective of the entire perspective by the second diffraction unit 230-2.

[0133] The image light IL2 emitted from the image light generating system 100-1 and forming the right side view of the entire view enters the light guide plate 210 via the relay optical system 220 to satisfy the total reflection condition. The image light IL2 propagated by repeated total reflection in the light guide plate 210 is incident on the right end of the first diffraction unit 230-1. Among the image light IL2 incident on the right end of the first diffraction unit 230-1, the image light IL2-1 including the first polarized light PL1 is diffracted toward the position P on the eyeball EB so as to form the center view of the entire view, and the image light IL2-2 including the second polarized light PL2 is totally reflected by the light guide plate 210 toward the right end of the second diffraction unit 230-2. The image light IL2-2 incident on the right end of the second diffraction unit 230-2 is diffracted toward the position P on the eyeball EB so as to form the right side view of the entire view.

[0134] The image light IL3 emitted from the image light generating system 100-1 and forming the center perspective of the entire perspective enters the light guide plate 210 via the relay optical system 220 to satisfy the total reflection condition. The image light IL3 propagated by repeated total reflection in the light guide plate 210 is incident on the center of the first diffraction unit 230-1. Among the image light IL3 incident on the center of the first diffraction unit 230-1, the image light IL3-1 including the first polarized light PL1 is diffracted toward the position P on the eyeball EB so as to form an intermediate perspective between the left perspective and the center perspective of the entire perspective, and the image light IL3-2 including the second polarized light PL2 is totally reflected by the light guide plate 210 toward the center of the second diffraction unit 230-2. The image light IL3-2 incident on the center of the second diffraction unit 230-2 is diffracted toward the position P on the eyeball EB so as to form an intermediate perspective between the right perspective and the center perspective of the entire perspective.

[0135] <2. Display device according to second embodiment of the present technology>

[0136] Hereinafter, a display device according to a second embodiment of the present technology will be described in detail through some examples.

[0137] (Example 1)

[0138] 8 is a schematic diagram showing the configuration of a display device 20-1 of Example 1 of a second embodiment of the present technology. The display device 20-1 has a configuration substantially similar to the display device 10 according to the first embodiment, except that the first diffraction unit 230-1 and the second diffraction unit 230-2 have circular polarization selectivity and the light guide system 200-2 has a phase difference film 240.

[0139] In the display device 20-1, as an example, a cholesteric liquid crystal element having cholesteric liquid crystal is used as each diffraction unit 230. The cholesteric liquid crystal element has a characteristic of selectively acting on circularly polarized light. That is, the cholesteric liquid crystal element has an effective diffraction rate for one of right-handed circularly polarized light and left-handed circularly polarized light (see, for example, A of FIG. 10 and B of FIG. 10). Here, the first diffraction unit 230-1 has an effective diffraction rate for right-handed circularly polarized light, but does not have an effective diffraction rate for left-handed circularly polarized light. The second diffraction unit 230-2 has an effective diffraction rate for left-handed circularly polarized light, but does not have an effective diffraction rate for right-handed circularly polarized light.

[0140] Fig. 9A and Fig. 9B are a side view and a plan view, respectively, of the configuration example 1 of the diffraction unit 230. Fig. 10A and Fig. 10B are schematic diagrams showing the circular polarization selectivity of the configuration example 1 of the diffraction unit. Fig. 11A and Fig. 11B are views showing the liquid crystal molecule arrays of the first diffraction unit 230-1 and the second diffraction unit 230-2 in a plan view, respectively.

[0141] As the diffraction unit 230, the cholesteric liquid crystal element has, for example, a periodic structure, wherein the cholesteric liquid crystal element has a period in the x direction and the y direction in A of FIG. 9 , and as shown in B of FIG. 9 , in a plan view, the liquid crystal molecules rotate 180° in their period. In the periodic structures of the first diffraction unit 230-1 and the second diffraction unit 230-2, the rotation directions of the liquid crystal molecules are opposite to each other (see A of FIG. 11 and B of FIG. 11 ). Here, a periodic structure suitable for propagating through a light guide plate 210 having a refractive index of 1.6 at a total reflection angle of 55° and diffracting at 0° (the center of the viewing angle) is representatively shown. In A of FIG. 9 , t represents the thickness of the cholesteric liquid crystal element. In B of FIG. 9 , n represents the thickness of the cholesteric liquid crystal element. e represents the extraordinary refractive index of the cholesteric liquid crystal element (e.g., 1.7), and n orepresents the ordinary light refractive index of the cholesteric liquid crystal element (e.g., 1.5).

[0142] Figures 12A and 12B are a side view and a plan view of the configuration example 2 of the diffraction unit 230, respectively. Figures 13A and 13B are schematic diagrams showing the right-handed circular polarization selectivity and the left-handed circular polarization selectivity of the configuration example 2 of the diffraction unit 230. The configuration example 2 of the diffraction unit 230 has a structure in which the liquid crystal molecules rotate in the xy plane (a structure tilted at an angle θs relative to the y direction). With this structure, in each diffraction unit 230, the selectivity for the corresponding circularly polarized light can be made stronger, and almost no stray light is generated. Note that Figure 13A shows the diffraction rate of each wavelength of the circularly polarized light corresponding to the configuration example 2 of the diffraction unit 230, and Figure 13B shows the diffraction rate of each wavelength of the circularly polarized light that does not correspond to the configuration example 2 of the diffraction unit 230.

[0143] 14A to 14C are views showing configuration examples 1 to 3 of the diffraction unit 230, respectively. The upper view of FIG14C is a side view of configuration example 3 of the diffraction unit 230. The lower view of FIG14C is a plan view of configuration example 3 of the diffraction unit 230. Configuration example 3 of the diffraction unit 230 shown in FIG14C has a structure in which a cholesteric liquid crystal element 230a and a diffraction element 230b (in which materials having different refractive indexes are arranged at equal intervals in the in-plane direction) are stacked. In configuration example 3, in each diffraction unit, selectivity for the corresponding circularly polarized light becomes stronger, and stray light is hardly generated.

[0144] At the same time, when the image light propagates in the light guide plate, each time total reflection occurs, different phase differences are given to the S polarization component and the P polarization component in the circularly polarized light. Therefore, there is a problem of changing the polarization state whenever total reflection occurs. Therefore, it is desirable to select the polarization state of the light emitted from the light source unit by considering the phase difference provided until the light is incident on each diffraction unit 230 after total reflection, so that the right-handed circularly polarized light and the left-handed circularly polarized light are incident on the first diffraction unit 230-1. In addition, since total reflection still occurs after the light has passed through the first diffraction unit 230-1, it is preferred to arrange the phase difference film 240 for adjusting the polarization state on the optical path of the image light IL, so that at least one of the right-handed circularly polarized light or the left-handed circularly polarized light is continuously incident on the second diffraction unit 230-2. For example, the phase difference film 240 can be stacked and arranged on the diffraction unit 230, or can be arranged at the total reflection position of the image light IL on the light guide plate 210. The number and arrangement position of the phase difference film 240 can be appropriately changed.

[0145] Returning to FIG. 8 , the display device 20-1 according to Example 1 of the second embodiment has a configuration in which each of the plurality of diffraction units 230 has circular polarization selectivity, and the first circularly polarized light and the second circularly polarized light having different (mutually opposite) polarization directions are incident on the first diffraction unit 230-1 and the second diffraction unit 230-2, respectively. One of the first and second circularly polarized lights is right-handed circularly polarized light, and the other is left-handed circularly polarized light. Specifically, the first diffraction unit 230-1 has polarization selectivity (effective diffraction rate) for the first circularly polarized light, and does not have polarization selectivity (effective diffraction rate) for the second circularly polarized light. The second diffraction unit 230-2 has polarization selectivity (effective diffraction rate) for the second circularly polarized light, and does not have polarization selectivity (effective diffraction rate) for the first circularly polarized light.

[0146] For example, in the light source unit 110-1, two linearly polarized lights (e.g., first polarized light PL1 and second polarized light PL2) emitted from the first light source 110a1 and the second light source 110a2 and having polarization directions orthogonal to each other may be converted into two circularly polarized lights having polarization directions opposite to each other by a quarter wave plate, and then the optical paths of the two circularly polarized lights may be synthesized to generate the image light IL. For example, the linearly polarized light (e.g., one of the first polarized light PL1 and the second polarized light PL2) emitted from one of the first light source 110a1 and the second light source 110a2 may be converted into the first circularly polarized light by a quarter wave plate, and the optical path of the first circularly polarized light and the optical path of the second circularly polarized light (e.g., the other of the first polarized light PL1 and the second polarized light PL2) emitted from the other light source may be synthesized to generate the image light IL.

[0147] In the display device 20-1 of Example 1 according to the second embodiment, the first diffraction unit 230-1 and the second diffraction unit 230-2 preferably each have a cholesteric liquid crystal element. In this case, the rotation direction of the liquid crystal molecules in the cholesteric liquid crystal element of the first diffraction unit 230-1 is preferably opposite to the rotation direction of the liquid crystal molecules in the cholesteric liquid crystal element of the second diffraction unit 230-2. In addition, in the cholesteric liquid crystal elements of the first diffraction unit 230-1 and the second diffraction unit 230-2, the orientation direction of the liquid crystal molecules may be inclined relative to the thickness direction.

[0148] In the display device 20-1, in the light guide system 200-2, a phase difference film 240 is provided on the surface of the first diffraction unit 230-1 on the eyeball EB side. Here, the phase difference of the second polarized light PL2 included in the image light IL is adjusted by the phase difference film 240, so that at least light having a corresponding polarization state (for example, right-handed or left-handed circularly polarized light) is incident on the second diffraction unit 230-2.

[0149] (Example 2)

[0150] 15 is a schematic diagram showing the configuration of a display device 20-2 of Example 2 of the second embodiment of the present technology. In the display device 20-2, in the light guide system 200-3, a phase difference film 240 is provided between the second diffraction unit 230-2 and the light guide plate 210. Here, the phase difference of the second polarized light PL2 is adjusted by the phase difference film 240 so that at least light having a corresponding polarization state (e.g., right-handed or left-handed circularly polarized light) is incident on the second diffraction unit 230-2.

[0151] (Example 3)

[0152] 16 is a schematic diagram showing the configuration of a display device 20-3 of Example 3 of the second embodiment of the present technology. In the display device 20-3, in the light guide system 200-4, the first phase difference film 240-1 is provided between the first diffraction unit 230-1 and the light guide plate 210, and the second phase difference film 240-2 is provided between the second diffraction unit 230-2 and the light guide plate 210. Here, the phase difference of the first polarized light PL1 included in the image light IL is adjusted by the first phase difference film 240-1, so that at least light having a corresponding polarization state (for example, one of the right-handed circularly polarized light and the left-handed circularly polarized light) is incident on the first diffraction unit 230-1. Here, the phase difference of the second polarized light PL2 is adjusted by the first phase difference film 240-1 and the second phase difference film 240-2, so that at least light having a corresponding polarization state (for example, the other of the right-handed circularly polarized light and the left-handed circularly polarized light) is incident on the second diffraction unit 230-2.

[0153] (Example 4)

[0154] 17 is a schematic diagram showing the configuration of a display device 20-4 of Example 4 of the second embodiment of the present technology. In the display device 20-4, in the light guide system 200-5, a first phase difference film 240-1 is provided at a total reflection position before (for example, immediately before) a total reflection position of a light guide plate 210 where a first diffraction unit 230-1 is provided, and a second phase difference film 240-2 is provided between the second diffraction unit 230-2 and the light guide plate 210. Here, the phase difference of the first polarized light PL1 included in the image light IL is adjusted by the first phase difference film 240-1 so that at least light having a corresponding polarization state (for example, one of right-handed circularly polarized light and left-handed circularly polarized light) is incident on the first diffraction unit 230-1. Here, the phase difference of the second polarized light PL2 is adjusted by the first phase difference film 240-1 and the second phase difference film 240-2 so that at least light having a corresponding polarization state (eg, the other of right circular polarized light and left circular polarized light) is incident on the second diffraction unit 230-2.

[0155] (Example 5)

[0156] 18 is a schematic diagram showing the configuration of a display device 20-5 of Example 5 of the second embodiment of the present technology. In the display device 20-5, in the light guide system 200-6, the first phase difference film 240-1 is arranged at a total reflection position before (for example, immediately before) the total reflection position of the light guide plate 210 where the first diffraction unit 230-1 is arranged, and the second phase difference film 240-2 is arranged on the surface of the eyeball EB side of the first diffraction unit 230-1. Here, the phase difference of the first polarized light PL1 included in the image light IL is adjusted by the first phase difference film 240-1 so that at least light having a corresponding polarization state (for example, one of the right-handed circularly polarized light and the left-handed circularly polarized light) is incident on the first diffraction unit 230-1. The phase difference of the second polarized light PL2 is adjusted by the second phase difference film 240-2 so that at least light having a corresponding polarization state (for example, the other of the right-handed circularly polarized light and the left-handed circularly polarized light) is incident on the second diffraction unit 230-2.

[0157] (Example 6)

[0158] 19 is a schematic diagram showing the configuration of a display device 20-6 of Example 6 of the second embodiment of the present technology. In the display device 20-6, in the light guide system 200-7, a first phase difference film 240-1 is provided at a total reflection position before (for example, immediately before) a total reflection position of a light guide plate 210 where a first diffraction unit 230-1 is provided, a second phase difference film 240-2 is provided on a surface of the first diffraction unit 230-1 on the eyeball EB side, and a third phase difference film 240-3 is provided between the second diffraction unit 230-2 and the light guide plate 210. Here, the phase difference of the first polarized light PL1 included in the image light IL is adjusted by the first phase difference film 240-1 and the second phase difference film 240-2 so that at least light having a corresponding polarization state (for example, one of right-handed circularly polarized light and left-handed circularly polarized light) is incident on the first diffraction unit 230-1. The phase difference of the second polarized light PL2 is adjusted by the first to third phase difference films 240-1, 240-2 and 240-3 so that at least light having a corresponding polarization state (eg, the other of right circularly polarized light and left circularly polarized light) is incident on the second diffraction unit 230-2.

[0159] <3. Display device according to third embodiment of the present technology>

[0160] Hereinafter, a display device of a third embodiment of the present technology will be described with reference to the accompanying drawings. FIG20 is a schematic diagram showing a configuration of a display device 30 of a third embodiment of the present technology. The display device 30 has a configuration similar to that of the display device 10 according to the first embodiment, except that the emission optical system 120-2 in the image light generating system 100-2 includes another diffraction unit 120c for correcting the chromatic aberration of the diffraction unit 230.

[0161] Another diffraction unit 120c is disposed on the optical path of the image light IL between the light source unit 110-1 and the light deflector 120b, and corrects chromatic aberration of at least one of the first diffraction unit 230-1 or the second diffraction unit 230-2.

[0162] The above-described display device 30 can display images with higher image quality.

[0163] <4. Display device according to fourth embodiment of the present technology>

[0164] Hereinafter, a display device according to a fourth embodiment of the present technology will be described with reference to the accompanying drawings. FIG21 is a schematic diagram showing a configuration of a display device 40 according to a fourth embodiment of the present technology. FIG22 is a block diagram showing functions of a display device 40 according to a fourth embodiment of the present technology.

[0165] The display device 40 has a configuration substantially similar to that of the display device 30 according to the third embodiment, except that a line of sight detection system 500 (see FIG. 22 ) is provided and the emitting optical system 120 - 3 in the image light generating system 100 - 3 includes a driving unit 120 d (optical element control unit) capable of moving the optical element 120 a in the direction of its optical axis.

[0166] Examples of the driving unit 120 d include a linear motor, a combination of a rack and pinion mechanism and a driving source (eg, a motor), a combination of a ball screw mechanism and a driving source (eg, a motor), and the like.

[0167] As shown in FIG22 , the sight line detection system 500 detects the direction of the eyeball EB (i.e., the sight line direction) and outputs the detection result to the control system 400. The sight line detection system 500 includes a light receiving / emitting unit 500a (see FIGS. 21 and 22 ) and a signal processing unit 500b (see FIG22 ). The light receiving / emitting unit 500a includes a light emitting element that irradiates the eyeball EB with invisible light (e.g., infrared light) and a light receiving element (e.g., a four-quadrant photodiode (PD), an image sensor, etc.) in which a plurality of light receiving units are arranged two-dimensionally. The signal processing unit 500b processes the output signals of the plurality of light receiving units in the light receiving element and calculates the sight line direction.

[0168] The control system 400 controls the driving unit 120d based on the detection result of the line of sight detection system 500. Specifically, the control system 400 controls the driving unit 120d to move the optical element 120a in the optical axis direction of the optical element 120a according to the line of sight direction GD (also referred to as the gaze direction GD) which is the direction of the eyeball EB, thereby controlling the divergence angle and / or the beam shape of the image light IL.

[0169] For example, as shown in FIG. 21 , first, the position of the optical element 120 a having a suitable divergence angle and beam shape of image light (eg, IL2 - 1 and IL1 - 2 ) incident on the eyeball EB along the gaze direction GD when the gaze direction GD is toward the front is set as a reference position.

[0170] For example, as shown in FIG. 23, when the gaze direction GD points to the left side, the control system 400 controls the driving unit 120d to move the optical element 120a relative to the reference position to a position on the side of the light deflector 120b, at which position the divergence angle and beam shape of the image light (e.g., IL1-1 and IL3-1) incident on the eyeball EB along the gaze direction GD are appropriate.

[0171] For example, as shown in Figure 24, when the gaze direction GD points to the right, the control system 400 controls the driving unit 120d to move the optical element 120a relative to the reference position to a position on the side of the other diffraction unit 120c, at which position the divergence angle and beam shape of the image light (e.g., IL2-2 and IL3-2) incident on the eyeball EB along the gaze direction GD are appropriate.

[0172] According to the display device 40 described above, an image with good visibility can be displayed regardless of the user's line of sight direction.

[0173] In the display device 40 according to the fourth embodiment, the optical element control unit moves the optical element 120a in the optical axis direction of the optical element 120a, but the optical element control unit is not limited thereto. For example, the optical element control unit may change the focal length of the optical element by changing the surface shape of the optical element having a variable surface shape, or may change the focal length of the optical element by controlling the optical element including a material such as liquid crystal. In addition, in these cases, the same effect as the display device 40 can be obtained.

[0174] <5. Display device according to fifth embodiment of the present technology>

[0175] Hereinafter, a display device of a fifth embodiment of the present technology will be described with reference to the drawings. FIG25 is a schematic diagram showing a configuration of a display device 50 of a fifth embodiment of the present technology. FIG26 is a schematic diagram showing a configuration example of a light source unit 110-2 of the display device 50.

[0176] The display device 50 has a configuration substantially similar to that of the display device 10 according to the first embodiment, except that the light guiding system 200-8 includes three diffraction units 230 (e.g., first to third diffraction units 230-1, 230-2, and 230-3) (see FIG. 25 ) and the image light IL includes three polarized lights having different polarization states (e.g., first to third polarized lights PL1, PL2, and PL3) (see FIG. 26 ).

[0177] In the light guide system 200-8, as shown in FIG25, as an example, the first diffraction unit 230-1 and the third diffraction unit 230-3 are arranged on the surface 210b of the side opposite to the eyeball EB side of the light guide plate 210 to be separated from each other in the left-right direction, and the second diffraction unit 230-2 is arranged on the surface 210a on the eyeball EB side of the light guide plate 210, and when viewed from the thickness direction of the light guide plate 210, the second diffraction unit 230-2 is located at a position sandwiched between the first diffraction unit 230-1 and the third diffraction unit 230-3. Here, in three consecutive total reflection positions on the light guide plate 210, the first diffraction unit 230-1 is arranged at the first total reflection position, the second diffraction unit 230-2 is arranged at the next total reflection position, and the third diffraction unit 230-3 is arranged at the last total reflection position.

[0178] As shown in FIG. 26 , as an example, the light source unit 110-2 of the image light generating system 100-4 includes a first light source 110a1 that emits a first polarized light PL1, a second light source 110a2 that emits a second polarized light PL2, and a third light source 110a3 that emits a third polarized light PL3. Each light source is driven (turned on / off) by a light source driving circuit 110b. A first beam splitter 110c1 (e.g., a one-way mirror) is arranged at the intersection of the optical path of the first polarized light PL1 and the optical path of the second polarized light PL2. A second beam splitter 110c2 (e.g., a one-way mirror) is arranged at the intersection of the optical path of the synthesized light of the first polarized light PL1 and the second polarized light PL2 and the optical path of the third polarized light PL3. The synthesized light of the first polarized light PL1 to the third polarized light PL3 ​​is emitted from the second beam splitter 110c2 as the image light IL.

[0179] Returning to FIG. 25 , in the light guiding system 200 - 8 , the first diffraction unit 230 - 1 has polarization selectivity for the first polarized light PL1 , the second diffraction unit 230 - 2 has polarization selectivity for the second polarized light PL2 , and the third diffraction unit 230 - 3 has polarization selectivity for the third polarized light PL3 ​​.

[0180] Hereinafter, the operation of the display device 50 is described. Here, as an example, a case where the diffraction rate of each diffraction unit 230 for light of a corresponding polarization state is 100% will be described. In the display device 50, the image light IL (e.g., image lights IL1, IL2, and IL3) emitted from the image light generating system 100-4 is incident on the light guide plate 210 via the relay optical system 220, propagates through the light guide plate 210 while being repeatedly totally reflected, and then is incident on the first diffraction unit 230-1.

[0181] In the image light IL1 incident on the first diffraction unit 230-1, the image light IL1-1 including the first polarized light PL1 is diffracted toward the eyeball EB to form the leftmost viewing angle of the entire viewing angle, and the second polarized light PL2 and the third polarized light PL3 ​​are totally reflected by the light guide plate 210 toward the second diffraction unit 230-2. In the image light IL2 incident on the first diffraction unit 230-1, the image light IL2-1 including the first polarized light PL1 is diffracted toward the eyeball EB to form the first intermediate viewing angle on the left side of the entire viewing angle, and the second polarized light PL2 and the third polarized light PL3 ​​are totally reflected by the light guide plate 210 toward the second diffraction unit 230-2. In the image light IL3 incident on the first diffraction unit 230-1, the image light IL3-1 including the first polarized light PL1 is diffracted toward the eyeball EB to form the second intermediate viewing angle on the left side between the leftmost viewing angle of the entire viewing angle and the first intermediate viewing angle, and the second polarized light PL2 and the third polarized light PL3 ​​are totally reflected by the light guide plate 210 toward the second diffraction unit 230-2.

[0182] Among the image light IL1 incident on the second diffraction unit 230-2, the image light IL1-2 including the second polarized light PL2 is diffracted toward the eyeball EB to form a first intermediate viewing angle on the left side of the entire viewing angle, and the third polarized light PL3 ​​is totally reflected by the light guide plate 210 toward the third diffraction unit 230-3. Among the image light IL2 incident on the second diffraction unit 230-2, the image light IL2-2 including the second polarized light PL2 is diffracted toward the eyeball EB to form a first intermediate viewing angle on the right side of the entire viewing angle, and the third polarized light PL3 ​​is totally reflected by the light guide plate 210 toward the third diffraction unit 230-3. Among the image light IL3 incident on the second diffraction unit 230-2, the image light IL3-2 including the second polarized light PL2 is diffracted toward the eyeball EB to form a central viewing angle of the entire viewing angle, and the third polarized light PL3 ​​is totally reflected by the light guide plate 210 toward the third diffraction unit 230-3.

[0183] In the image light IL1 incident on the third diffraction unit 230-3, the image light IL1-3 including the third polarized light PL3 ​​is diffracted toward the eyeball EB to form a first intermediate viewing angle on the right side of the entire viewing angle. In the image light IL2 incident on the third diffraction unit 230-3, the image light IL2-3 including the third polarized light PL3 ​​is diffracted toward the eyeball EB to form the rightmost viewing angle of the entire viewing angle. In the image light IL3 incident on the third diffraction unit 230-3, the image light IL3-3 including the third polarized light PL3 ​​is diffracted toward the eyeball EB to form a second intermediate viewing angle located between the rightmost viewing angle of the entire viewing angle and the first intermediate viewing angle on the right side.

[0184] The display device 50 can display images at a wider viewing angle.

[0185] (Example of closely arranging diffraction elements on both surfaces of a light guide plate)

[0186] FIG. 27A is a schematic diagram showing an example of closely arranging diffraction units on both surfaces of a light guide plate. FIG. 27B is a schematic diagram showing an example of arranging diffraction units on one surface of a light guide plate. In the example of FIG. 27A, a first diffraction unit 230-1 and a third diffraction unit 230-3 are arranged adjacent to each other on one surface of a light guide plate 210 (e.g., a surface on one side of an eyeball), and a second diffraction unit 230-2 is arranged on another surface of the light guide plate 210 (e.g., a surface on the opposite side to one side of an eyeball) so as to overlap both the first diffraction unit 230-1 and the third diffraction unit 230-3 when viewed from the thickness direction of the light guide plate 210. By closely arranging the diffraction unit 230 on both surfaces of the light guide plate 210 in this way, the distance between adjacent focal points (the distance between focal points) formed by the diffraction unit can be made approximately half the size of the diffraction unit, for example. As a result, the focal points can be formed more closely, the focal points can be suppressed from deviating from the eyeball, and the image can be prevented from disappearing.

[0187] In the example of B of FIG. 27 , the first diffraction unit 230-1 and the third diffraction unit 230-3 are disposed adjacent to each other on one surface of the light guide plate 210. In this case, the distance between the focal points is approximately the size of the diffraction unit. In this case, there is a possibility that the focal point deviates from the eyeball and the image disappears.

[0188] <6. Display device according to the sixth embodiment of the present technology>

[0189] Hereinafter, a display device of a sixth embodiment of the present technology will be described with reference to the drawings. Fig. 28 is a schematic diagram showing a configuration of a display device 60 of a sixth embodiment of the present technology.

[0190] The display device 60 has substantially the same configuration as that of the display device 10 according to the first embodiment, except that two focal points P1 and P2 are formed on the eyeball EB using three diffraction units (eg, first to third diffraction units 230 - 1 to 230 - 3 ).

[0191] In the light guide system 200 - 9 of the display device 60 , the arrangement of the first to third diffraction units 230 - 1 to 230 - 3 is the same as that of the light guide system 200 - 8 of the display device 50 according to the fifth embodiment.

[0192] In the light guide system 200-9, the first diffraction unit 230-1 has polarization selectivity for the first polarized light PL1, the second diffraction unit 230-2 has polarization selectivity for the first polarized light PL1 and the second polarized light PL2, and the third diffraction unit 230-3 has polarization selectivity for the second polarized light PL2. Here, the diffraction efficiency of the first diffraction unit 230-1 and the second diffraction unit 230-2 for the light of the corresponding polarization state is about 30% to 70% (preferably 50%).

[0193] That is, the first diffraction unit 230-1 and the second diffraction unit 230-2 correspond to the same polarization state (first polarized light PL1) and correspond to different polarization states (first polarized light PL1 and second polarized light PL2). The second diffraction unit 230-2 and the third diffraction unit 230-3 correspond to the same polarization state (second polarized light PL2) and correspond to different polarization states (first polarized light PL1 and second polarized light PL2). The first diffraction unit 230-1 and the third diffraction unit 230-3 correspond to different polarization states (first polarized light PL1 and second polarized light PL2).

[0194] As an example, the second diffraction unit 230-2 is a diffraction unit in which a plurality of diffraction patterns corresponding to different polarization states (first polarized light PL1 and second polarized light PL2) are formed in a plurality of ways, or a diffraction unit in which a plurality of layers of diffraction patterns corresponding to different polarization states (first polarized light PL1 and second polarized light PL2) are stacked to form.

[0195] In the light guide system 200-9, the first diffraction unit 230-1 and the second diffraction unit 230-2 form a first viewing angle AV1 starting from the focus P1, and the second diffraction unit 230-2 and the third diffraction unit 230-3 form a second viewing angle AV2 starting from the focus P2.

[0196] In the display device 60, the image light IL (for example, image lights IL1, IL2, and IL3) emitted from the image light generating system 100-1 is incident on the light guide plate 210 via the relay optical system 220, propagates through the light guide plate 210 while being repeatedly totally reflected, and then is incident on the first diffraction unit 230-1.

[0197] Among the image light IL1 incident on the first diffraction unit 230-1, the image light IL1-1a including a part of the first polarized light PL1 is diffracted toward the eyeball EB to form the leftmost viewing angle of the first viewing angle AV1, and the remaining parts of the first polarized light PL1 and the second polarized light PL2 are totally reflected toward the second diffraction unit 230-2 by the light guide plate 210. Among the image light IL2 incident on the first diffraction unit 230-1, the image light IL2-1a including a part of the first polarized light PL1 is diffracted toward the eyeball EB to form the central viewing angle of the first viewing angle AV1, and the remaining parts of the first polarized light PL1 and the second polarized light PL2 are totally reflected toward the second diffraction unit 230-2 by the light guide plate 210. Among the image light IL3 incident on the first diffraction unit 230-1, the image light IL3-1a including a portion of the first polarized light PL1 is diffracted toward the eyeball EB to form an intermediate viewing angle on the left side of the first viewing angle AV1, and the remaining portions of the first polarized light PL1 and the second polarized light PL2 are totally reflected by the light guide plate 210 toward the second diffraction unit 230-2.

[0198] Among the image light IL1 incident on the second diffraction unit 230-2, the image light IL1-1b including the remaining part of the first polarized light PL1 is diffracted toward the eyeball EB to form the central viewing angle of the first viewing angle AV1, the image light IL1-2a including a part of the second polarized light PL2 is diffracted toward the eyeball EB to form the leftmost viewing angle of the second viewing angle AV2, and the remaining part of the second polarized light PL2 is totally reflected by the light guide plate 210 toward the third diffraction unit 230-3. Among the image light IL2 incident on the second diffraction unit 230-2, the image light IL2-1b including the remaining part of the first polarized light PL1 is diffracted toward the eyeball EB to form the rightmost viewing angle of the first viewing angle AV1, the image light IL2-2a including a part of the second polarized light PL2 is diffracted toward the eyeball EB to form the central viewing angle of the second viewing angle AV2, and the remaining part of the second polarized light PL2 is totally reflected by the light guide plate 210 toward the third diffraction unit 230-3. Among the image light IL3 incident on the second diffraction unit 230-2, the image light IL3-1b including the remaining part of the first polarized light PL1 is diffracted toward the eyeball EB to form a middle viewing angle on the right side of the first viewing angle AV1, the image light IL3-2a including a part of the second polarized light PL2 is diffracted toward the eyeball EB to form a middle viewing angle on the left side of the second viewing angle AV2, and the remaining part of the second polarized light PL2 is totally reflected by the light guide plate 210 toward the third diffraction unit 230-3.

[0199] In the image light IL1 incident on the third diffraction unit 230-3, the image light IL1-2b including the remaining part of the second polarized light PL2 is diffracted toward the eyeball EB to form the center viewing angle of the second viewing angle AV2. In the image light IL2 incident on the third diffraction unit 230-3, the image light IL2-2b including the remaining part of the second polarized light PL2 is diffracted toward the eyeball EB to form the rightmost viewing angle of the second viewing angle AV2. In the image light IL3 incident on the third diffraction unit 230-3, the image light IL3-2b including the remaining part of the second polarized light PL2 is diffracted toward the eyeball EB to form the middle viewing angle on the right side of the second viewing angle AV2.

[0200] The display device 60 can effectively prevent the image from disappearing.

[0201] <7. Display device according to seventh embodiment of the present technology>

[0202] Hereinafter, a display device according to a seventh embodiment of the present technology will be described in detail through some examples.

[0203] (Example 1)

[0204] Fig. 29A is a schematic diagram showing the configuration of the display device 70-1 of Example 1 of the seventh implementation mode of the present technical content. Fig. 29B is a schematic diagram for explaining the display method of the display device 70-1 of Example 1 of the seventh implementation mode of the present technical content. Fig. 30 is a schematic diagram showing an example of the configuration of the light source unit 110-3 in the display device 70-1.

[0205] The display device 70 - 1 has a configuration substantially similar to that of the display device 10 according to the first embodiment, except that the light source unit 110 - 3 generates the image light IL using a single light source 110 a (see FIG. 30 ).

[0206] In the light source unit 110 - 3 , the light source 110 a is a polarization light source capable of selectively emitting the first polarized light PL1 and the second polarized light PL2 (see FIG. 30 ).

[0207] In the display device 70-1, multiple beams of light with different polarization states included in the image light IL (e.g., first polarized light PL1 and second polarized light PL2) are incident on multiple corresponding diffraction units (e.g., first diffraction unit 230-1 and second diffraction unit 230-2) at different time periods (see Figure 29B).

[0208] As an example, the display device 70-1 irradiates the eyeball EB with image light (e.g., IL1-1, IL2-1, IL3-1) including the first polarized light PL1 in a first period (e.g., 0 to 1 / 120 seconds) to form a left half viewing angle area of ​​the entire viewing angle starting from the focus P, and irradiates the eyeball EB with image light (e.g., IL1-2, IL2-2, IL3-2) including the second polarized light PL2 in a second period (e.g., 0 to 1 / 120 seconds) to form a right half viewing angle area of ​​the entire viewing angle starting from the focus P. That is, an image perceived by a user as a viewer is formed in one frame including the first period and the second period.

[0209] The display device 70 - 1 can stably display an image with high image quality and a wide viewing angle using a single light source.

[0210] (Example 2)

[0211] Fig. 31A is a schematic diagram showing the configuration of the display device 70-2 of Example 2 of the seventh implementation mode of the present technical content. Fig. 31B is a schematic diagram for explaining the display method of the display device 70-2 of Example 2 of the seventh implementation mode of the present technical content. Fig. 32 is a schematic diagram showing an example of the configuration of the light source unit 110-4 in the display device 70-2.

[0212] The display device 70 - 2 has a configuration substantially similar to that of the display device 50 according to the fifth embodiment, except that the light source unit 110 - 4 generates the image light IL using a single light source 110 a (see FIG. 32 ).

[0213] In the light source unit 110 - 4 , the light source 110 a is a polarization light source capable of selectively emitting first to third polarized lights PL1 , PL2 , and PL3 (see FIG. 32 ).

[0214] In the display device 70-2, multiple beams of light with different polarization states included in the image light IL (for example, first to third polarized light PL1, PL2 and PL3) are incident on multiple corresponding diffraction units (for example, first to third diffraction units 230-1, 230-2 and 230-3) at different time periods (see B of Figure 31).

[0215] As an example, the display device 70-2 irradiates the eyeball EB with image light (e.g., IL1-1, IL2-1, IL3-1) including the first polarized light PL1 in a first time period (e.g., 0 to 1 / 120 seconds) to form a left viewing angle area of ​​the entire viewing angle starting from the focus P, and irradiates the eyeball EB with image light (e.g., IL1-2, IL2-2, and IL3-2) including the second polarized light PL2 in a second time period (e.g., 0 to 1 / 120 seconds) to form a central viewing angle area of ​​the entire viewing angle starting from the focus P. And irradiates the eyeball EB with image light (e.g., IL1-3, IL2-3, and IL3-3) including the third polarized light PL3 ​​in a third time period (2 / 120 to 3 / 120 seconds) to form a right viewing angle of the entire viewing angle starting from the focus P. That is, an image perceived by a user as a viewer is formed in one frame including the first to third time periods.

[0216] The display device 70 - 2 can stably display an image with high image quality and a wider viewing angle using a single light source.

[0217] (Example 3)

[0218] Fig. 33A is a schematic diagram showing the configuration of a display device 70-3 of Example 3 of the seventh embodiment of the present technology. Fig. 33B is a schematic diagram for explaining a display method of the display device 70-3 of Example 3 of the seventh embodiment of the present technology.

[0219] The display device 70 - 3 has a configuration substantially similar to that of the display device 60 according to the sixth embodiment, except that the light source unit 110 - 3 generates the image light IL using a single light source 110 a (see FIG. 30 ).

[0220] In the light source unit 110 - 3 , the light source 110 a may selectively emit the first polarized light PL1 and the second polarized light PL2 (see FIG. 30 ).

[0221] In the display device 70-3, multiple beams of light with different polarization states included in the image light IL (for example, the first polarized light PL1 and the second polarized light PL2) are incident on multiple corresponding diffraction units (for example, the first diffraction unit 230-1 and the second diffraction unit 230-2) at different time periods (see B of Figure 33).

[0222] As an example, the display device 70-3 irradiates the eyeball EB with image light (e.g., IL1-1a, IL1-1b, IL2-1a, IL2-1b, IL3-1a, and IL3-1b) including the first polarized light PL1 in a first time period (e.g., 0 to 1 / 120 seconds) to form a first viewing angle AV1 starting from the focus P1, and irradiates the eyeball EB with image light (e.g., IL1-2a, IL1-2b, IL2-2a, IL2-2b, IL3-2a, and IL3-2b) including the second polarized light PL2 in a second time period (e.g., 0 to 1 / 120 seconds) to form a second viewing angle AV2 starting from the focus P2. That is, an image perceived by a user as a viewer is formed in one frame including the first time period and the second time period.

[0223] The display device 70 - 3 can stably display an image with high image quality and a wide viewing angle using a single light source while effectively preventing the image from disappearing.

[0224] <8. Modifications of the present technology>

[0225] The configuration of the display device of each embodiment of the present technology described above can be changed appropriately.

[0226] The configuration of the relay optical system 220 can be changed appropriately. For example, in the modification 1 shown in FIG. 34, the relay optical system 220 includes a collimator lens 220b arranged on the optical path of the image light IL from the image light generating system, and a prism 220c arranged on the optical path of the image light IL after passing through the collimator lens 220b. The prism 220c is attached to one surface of the light guide plate 210 (for example, the surface on the eyeball side).

[0227] The image light IL emitted from the image light generating system is converted into substantially parallel light by the collimating lens 220 b , passes through the prism 220 c , and is incident on the light guide plate 210 at an incident angle satisfying a total reflection condition in the light guide plate 210 .

[0228] For example, in the modification 2 shown in FIG. 35 , the relay optical system 220 includes a free-form surface prism 220 d arranged on the optical path of the image light IL from the image light generating system. For example, the free-form surface prism 220 d is attached to one surface (for example, the surface on the side opposite to the eyeball) of the light guide plate 210. The image light IL emitted from the image light generating system is totally reflected and converted into substantially parallel light by the free-form surface prism, and is incident on the light guide plate 210 at an incident angle that satisfies the total reflection condition in the light guide plate 210.

[0229] For example, at least one diffraction unit 230 having polarization selectivity and at least one diffraction unit not having polarization selectivity may be combined to display a wide-angle view image. In this case, for example, if the diffraction efficiency of the diffraction unit 230 for light of the corresponding polarization state is high, a wide-angle image with high image quality can also be stably displayed while suppressing the generation of stray light.

[0230] For example, in each of the above-mentioned embodiments and variations, image light including multiple polarized lights is emitted from the light source unit, but image light including multiple polarized lights and at least one non-polarized light may also be emitted from the light source unit, or image light including at least one polarized light and at least one non-polarized light may be emitted from the light source unit. In this case, at least one diffraction unit with polarization selectivity and at least one diffraction unit without polarization selectivity may be provided. For example, in the case where at least one diffraction unit has a single polarization selectivity, a single polarized light corresponding to the single polarization selectivity may be emitted from the light source unit. Furthermore, in this case, in addition to the single polarized light, at least one non-polarized light may also be emitted from the light source unit.

[0231] The number and arrangement of the diffraction units 230 are not limited to the above-mentioned embodiments and variations. For example, the number and arrangement can be appropriately changed according to the size of the entire viewing angle of the displayed image, the size of the diffraction unit 230, the number of polarized lights with different polarization states included in the image light, whether there are diffraction units without polarization selectivity, etc. In this case, at least one diffraction unit 230 can have polarization selectivity for multiple polarized lights. Specifically, at least one diffraction unit 230 can be a diffraction unit in which multiple diffraction patterns corresponding to different polarization states are formed in a variety of ways, or a diffraction unit in which multiple layers of diffraction patterns corresponding to different polarization states are stacked. In the case of providing multiple diffraction units 230, at least two diffraction units 230 can correspond to the same polarization state or can correspond to different polarization states. For example, at least two diffraction units 230 corresponding to the same polarization state can be respectively arranged at at least two continuous total reflection positions on the light guide plate 210. In this case, by emitting light of the same polarization state corresponding to each diffraction unit from the light source unit and adjusting the diffraction rate of at least one diffraction unit 230, substantially equal amounts of image light can be incident on each diffraction unit 230.

[0232] In each of the above-described embodiments and modifications, the diffraction unit 230 is disposed on both surfaces of the light guide plate 210 , but may be disposed on only one surface.

[0233] In each of the above embodiments and variations, the light source unit includes a polarized light source, but in addition or instead thereof, a non-polarized light source and at least one wave plate (eg, half-wave plate, quarter-wave plate) may be combined to generate a plurality of polarized lights having different polarization states.

[0234] For example, in each of the above embodiments and variations, the light guide system may not include a light guide plate.For example, the light guide system may include at least one reflector.

[0235] The configurations of the above-described embodiment and modified examples may be combined with each other within a range not contradictory.

[0236] Furthermore, the present technology can also adopt the following configurations.

[0237] (1) A display device comprising:

[0238] an image light generating system that generates image light; and

[0239] a light guide system that guides the image light generated by the image light generating system to the user's eyeball, wherein

[0240] The light guiding system comprises a diffraction unit with polarization selectivity.

[0241] At least light having a corresponding polarization state in the image light is incident on the diffraction unit, and

[0242] The diffraction unit diffracts the incident light with the corresponding polarization state toward the eyeball.

[0243] (2) The display device according to (1), wherein the light guide system includes a plurality of the diffraction elements.

[0244] (3) The display device according to (2), wherein at least two of the plurality of diffraction elements correspond to different polarization states.

[0245] (4) The display device according to (2) or (3), wherein at least two of the plurality of diffraction elements correspond to the same polarization state.

[0246] (5) The display device according to (2) to (4), wherein the plurality of diffraction elements include at least two diffraction elements corresponding to different polarization states and at least two diffraction elements corresponding to the same polarization state.

[0247] (6) The display device according to any one of (2) to (5), wherein each of the plurality of diffraction units causes light of corresponding polarization states to be incident on the eyeball from directions different from each other.

[0248] (7) A display device according to any one of (2) to (6), wherein the light guide system includes a light guide plate that faces the eyeball and totally reflects and guides the incident image light generated by the image light generating system, and the plurality of diffraction units are disposed on the light guide plate.

[0249] (8) A display device according to (7), wherein the plurality of diffraction units include at least one diffraction unit arranged on the surface of the light guide plate on the eyeball side and / or at least one diffraction unit arranged on the surface of the light guide plate on the side opposite to the eyeball side.

[0250] (9) The display device according to (7) or (8), wherein the light guide system includes a relay optical system that causes the image light generated by the image light generating system to be incident on the light guide plate at an incident angle such that the image light is totally reflected in the light guide plate.

[0251] (10) The display device according to any one of (1) to (9), wherein the light having the corresponding polarization state is circularly polarized light, and the diffraction unit has circular polarization selectivity.

[0252] (11) A display device according to any one of (2) to (10), wherein the light having a corresponding polarization state is circularly polarized light, the plurality of diffraction units include a first diffraction unit and a second diffraction unit, at least a first circularly polarized light in the image light is incident on the first diffraction unit, at least a second circularly polarized light in the image light is incident on the second diffraction unit, a polarization direction of the second circularly polarized light is different from a polarization direction of the first circularly polarized light, the first diffraction unit has polarization selectivity for the first circularly polarized light, and the second diffraction unit has polarization selectivity for the second circularly polarized light.

[0253] (12) The display device according to (11), wherein the first diffraction unit and the second diffraction unit each include a cholesteric liquid crystal element.

[0254] (13) The display device according to (12), wherein the rotation directions of liquid crystal molecules in the cholesteric liquid crystal element of the first diffraction unit and the second diffraction unit are opposite to each other.

[0255] (14) The display device according to (12) or (13), wherein in the cholesteric liquid crystal elements of the first diffraction unit and the second diffraction unit, an alignment direction of liquid crystal molecules is inclined with respect to a thickness direction of the cholesteric liquid crystal element.

[0256] (15) The display device according to any one of (1) to (14), wherein the light guide system includes at least one phase difference film arranged on an optical path of the image light.

[0257] (16) A display device according to any one of (1) to (15), wherein the diffraction unit is a diffraction unit in which a plurality of diffraction patterns corresponding to different polarization states are formed in a plurality of ways or a diffraction unit in which a plurality of layers of diffraction patterns corresponding to different polarization states are stacked.

[0258] (17) The display device according to any one of (1) to (16), wherein the image light generating system includes a light source unit including a light source, and a light deflector that deflects light from the light source unit.

[0259] (18) The display device according to (17), wherein the image light generating system includes another diffraction unit that is arranged on an optical path of the image light between the light source unit and the light deflector and corrects chromatic aberration of the diffraction unit.

[0260] (19) The display device according to (17) or (18), wherein the image light generating system includes an optical element arranged on an optical path of the image light between the light source unit and the light deflector, and an optical element control unit that controls the optical element.

[0261] (20) The display device according to any one of (2) to (19), wherein the plurality of light beams having different polarization states in the image light are incident on the corresponding plurality of the diffraction elements at different time periods.

[0262] Reference numerals

[0263] 10, 20-1 to 20-6, 30, 40, 50, 60, 70-1 to 70-3 Display device

[0264] 100-1 to 100-6 Image light generation system

[0265] 110a, 110a1, 110a2, 110a3 Light source

[0266] 110-1 to 110-4 Light source unit

[0267] 120a Optical Components

[0268] 120b Light Deflector

[0269] 120c Another diffraction unit

[0270] 120d Driver

[0271] 200-1 to 200-9 Light guide system

[0272] 210 Light guide plate

[0273] 220 Relay Optical System

[0274] 230, 230-1, 230-2, 230-3 Diffraction Unit

[0275] 240, 240-1, 240-2, 240-3 Retardation Film

[0276] IL, IL1, IL2, IL3 Image light

[0277] EB Eyeball

Claims

1. A display device, comprising: an image light generating system, wherein the image light generating system generates image light; as well as a light guide system that guides the image light generated by the image light generating system to the user's eyeball, wherein The light guiding system comprises a diffraction unit with polarization selectivity, At least light having a corresponding polarization state in the image light is incident on the diffraction unit, and The diffraction unit diffracts the incident light with the corresponding polarization state toward the eyeball. 2 . The display device according to claim 1 , wherein the light guiding system comprises a plurality of the diffraction units. 3 . The display device according to claim 2 , wherein at least two of the plurality of diffraction units correspond to different polarization states. The display device according to claim 2 , wherein at least two of the plurality of diffraction elements correspond to the same polarization state. 5 . The display device according to claim 2 , wherein the plurality of diffraction units include at least two diffraction units corresponding to different polarization states and at least two diffraction units corresponding to the same polarization state. 6 . The display device according to claim 2 , wherein each of the plurality of diffraction units causes light of corresponding polarization states to be incident on the eyeball from directions different from each other.

7. The display device according to claim 2, wherein The light guide system includes a light guide plate that faces the eyeball and totally reflects and guides the incident image light generated by the image light generating system, and The plurality of diffraction units are disposed on the light guide plate.

8. The display device according to claim 7, wherein the plurality of diffraction units include at least one diffraction unit arranged on the surface of the light guide plate on the eyeball side and / or at least one diffraction unit arranged on the surface of the light guide plate on the side opposite to the eyeball side.

9. The display device according to claim 7, wherein the light guide system includes a relay optical system that causes the image light generated by the image light generating system to be incident on the light guide plate at an incident angle such that the image light is totally reflected in the light guide plate.

10. The display device according to claim 1, wherein The light having the corresponding polarization state is circularly polarized light, and The diffraction unit has circular polarization selectivity.

11. The display device according to claim 2, wherein The light having the corresponding polarization state is circularly polarized light, The plurality of diffraction units include a first diffraction unit and a second diffraction unit, at least a first circularly polarized light in the image light is incident on the first diffraction unit, at least a second circularly polarized light in the image light is incident on the second diffraction unit, and a polarization direction of the second circularly polarized light is different from a polarization direction of the first circularly polarized light, The first diffraction unit has polarization selectivity for the first circularly polarized light, and The second diffraction unit has polarization selectivity for the second circularly polarized light. 12 . The display device according to claim 11 , wherein the first diffraction unit and the second diffraction unit each include a cholesteric liquid crystal element. 13 . The display device according to claim 12 , wherein the liquid crystal molecules in the cholesteric liquid crystal elements of the first diffraction unit and the second diffraction unit have opposite rotation directions. 14 . The display device according to claim 12 , wherein in the cholesteric liquid crystal elements of the first diffraction unit and the second diffraction unit, an alignment direction of liquid crystal molecules is inclined with respect to a thickness direction of the cholesteric liquid crystal element. 15 . The display device according to claim 1 , wherein the light guiding system comprises at least one phase difference film arranged on an optical path of the image light. 16 . The display device according to claim 1 , wherein the diffraction unit is a diffraction unit in which a plurality of diffraction patterns corresponding to different polarization states are formed in a plurality of ways or a diffraction unit in which a plurality of layers of diffraction patterns corresponding to different polarization states are stacked.

17. The display device according to claim 1, wherein The image light generating system includes A light source unit, the light source unit comprising a light source, and A light deflector deflects light from the light source unit. 18 . The display device according to claim 17 , wherein the image light generating system includes another diffraction unit which is arranged on an optical path of the image light between the light source unit and the light deflector and corrects chromatic aberration of the diffraction unit.

19. The display device according to claim 17, wherein The image light generating system includes an optical element arranged on an optical path of the image light between the light source unit and the light deflector, and An optical element control unit controls the optical element.

20. The display device according to claim 2, wherein: The multiple beams of light with different polarization states in the image light are incident on the corresponding multiple diffraction units at different time periods.

Images