Display device

Abstract

To provide a display device capable of appropriately displaying a three-dimensional virtual image even when a position of a user's eye changes.SOLUTION: A display device comprises: an image light emitter that emits image light beams of a left-eye image and a right-eye image; a light guide body having an emission surface from which light incident from the image light emitter is emitted; and a controller that controls the image light emitter. The light guide body includes: a holographic element on which the image light beams emitted from the image light emitter are incident; and a light guide portion enclosing the holographic element. The controller identifies positions of both eyes of a user on the basis of a captured image of an imager that captures both eyes of the user, and adjusts positions where the image light beams are incident on the holographic element according to the positions of both eyes of the user.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a display device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known a technique for displaying a three-dimensional virtual image by emitting an image for the right eye and an image for the left eye having a parallax therebetween via a light guide plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2021 / 0294101 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, a right-eye waveguide is provided at a position corresponding to the right eye, and a left-eye waveguide is provided at a position corresponding to the left eye. Therefore, when the position of the user's eyes changes to the left or right across the center, the right eye and the left eye are located at positions corresponding to the right-eye waveguide, or the left eye and the right eye are located at positions corresponding to the left-eye waveguide, which causes a problem that a 3D virtual image cannot be displayed appropriately.

[0005] An object of the present disclosure is to provide a display device capable of appropriately displaying a three-dimensional virtual image even if the position of the user's eyes changes. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the display device of the present disclosure comprises an image light emitting section that emits image light for an image for the left eye and an image for the right eye, a light guide having an exit surface that emits light incident from the image light emitting section, and a control section that controls the image light emitting section, wherein the light guide has a hologram element into which the image light emitted from the image light emitting section is incident, and a light guide section that encapsulates the hologram element, and the control section is a display device that identifies the position of the user's eyes based on an image captured by an imaging section that images both of the user's eyes, and adjusts the position at which the image light is incident on the hologram element depending on the position of the user's eyes. Effect of the Invention

[0007] According to the present disclosure, a three-dimensional virtual image can be appropriately displayed even if the position of the user's eyes changes. Note that the effects described herein are not necessarily limited to those described herein, and may be any of the effects described herein. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of a schematic configuration of a display device according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of the hologram element according to the embodiment. [Diagram 3] FIG. 3 is a diagram illustrating an example of a hardware configuration of a control unit according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of functions of a control unit according to the embodiment. [Diagram 5] FIG. 5 is a schematic diagram for explaining the control by the control unit of the embodiment. [Figure 6] FIG. 6 is a schematic diagram for explaining the control by the control unit in the modified example. [Figure 7] FIG. 7 is a diagram for explaining the propagation distance. [Figure 8] FIG. 8 is a diagram showing the relationship between the interpupillary distance and the propagation distance. [Figure 9] FIG. 9 is a schematic diagram for explaining a mode in which a mirror coat is disposed on a light guiding section. [Figure 10] FIG. 10 is a schematic diagram for explaining the control by the control unit of the modified example. [Figure 11] FIG. 11 is a diagram for explaining the principle of changing the output angle depending on the viewing purpose. [Figure 12] FIG. 12 is a diagram for explaining a mode in which the output angle is changed depending on the viewing purpose. [Figure 13] Figure 13 is a diagram for explaining the principle of a configuration in which an emission image at a folding position of a folding hologram element corresponding to the position of a user's eyes and an emission image at an adjacent folding position to the folding position are emitted continuously from the emission surface of an emission hologram element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a display device according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0010] FIG. 1 is a diagram showing an example of a schematic configuration of a display device 1 according to the present embodiment. As shown in FIG. 1, the display device 1 includes an image light emitting section 10, a light guide 20, and a control section 30. The display device 1 is a light guide plate type hologram display, and displays a three-dimensional virtual image by projecting a right eye image and a left eye image emitted from an image light emitting unit 10 via a light guide 20. For example, by placing the display device 1 on the dashboard of a vehicle, it can also be used as a light guide plate type hologram HUD (head-up display). The specific configuration of the display device 1 will be described below.

[0011] The image light emitting unit 10 emits image light for a left eye image (two-dimensional image) and a right eye image (two-dimensional image). For example, the image light emitting unit 10 is configured with a small display device that displays the left eye image and the right eye image.

[0012] The light guide 20 has an exit surface that exits the image light incident from the image light exit unit 10. The image light exiting from the exit surface is guided to both eyes of the user, and the user can visually recognize a three-dimensional virtual image. The light guide 20 has a hologram element 40 into which the light emitted from the image light exit unit 10 enters, and a light guide unit 50 that contains the hologram element 40.

[0013] FIG. 2 is a diagram showing an example of the configuration of the hologram element 40 of this embodiment. As shown in Figure 2, hologram element 40 includes an incident hologram element 41 onto which the image light emitted by image light emitting section 10 is incident, a folded hologram element 42 onto which the image light emitted by incident hologram element 41 is incident, and an exit hologram element 43 onto which the image light emitted by folded hologram element 42 is incident and exits from exit surface 50S of light guide section 50.

[0014] In this case, the entrance hologram element 41, the return hologram element 42 and the exit hologram element 43 are each configured as a transmission type diffractive optical element.

[0015] In the present embodiment, the case where the hologram element 40 includes three hologram elements is illustrated, but the present invention is not limited to this. For example, the hologram element 40 may include two hologram elements. Specifically, the hologram element 40 may include at least two of the input hologram element 41, the folded hologram element 42, and the output hologram element 43.

[0016] In this case, when the hologram element 40 includes two hologram elements, an entrance hologram element 41 and a return hologram element 42 , the return hologram element 42 may have the function of the exit hologram element 43 .

[0017] Furthermore, when the hologram element 40 includes two hologram elements, the folding hologram element 42 and the emission hologram element 43 , the folding hologram element 42 may have the function of the entrance hologram element 41 .

[0018] Furthermore, when the hologram element 40 includes two hologram elements, the entrance hologram element 41 and the exit hologram element 43, the entrance hologram element may have the function of the return hologram element .

[0019] In the example of FIG. 2, the image light emitted by the image light emitting section 10 is incident on the entrance hologram element 41, diffracted by the entrance hologram element 41, and emitted toward the return hologram element . The image light incident on the folded hologram element 42 is diffracted while being expanded (magnified) in the light propagation direction in the folded hologram element 42 (the x direction in the example of FIG. 2), and is output toward the output hologram element 43. Furthermore, the image light incident on output hologram element 43 is diffracted while being expanded (magnified) in the light propagation direction in output hologram element 43 (y direction in the example of FIG. 2), and is output from output surface 50S of light guide section 50.

[0020] Further, light guiding section 50 of this embodiment is composed of a pair (two) of glass plates facing each other, and entrance hologram element 41, return hologram element 42, and exit hologram element 43 are sandwiched between the pair of glass plates.

[0021] 1, the explanation will be continued. The control unit 30 identifies the positions of the user's eyes (pupil positions) based on the captured images of the imaging unit 60 that captures the user's eyes, and adjusts the position at which the image light is incident on the hologram element 40 according to the positions of the user's eyes. The imaging unit 60 is, for example, a visible light camera, an infrared camera, a TOF sensor, or the like. More specifically, the control unit 30 determines the emission position where the image light from the emission hologram element 43 is emitted from the emission surface 50S of the light guide unit 50 based on the positions of both eyes of the user. That is, the control unit 30 determines the emission position of the image light corresponding to the left eye image so that the image light corresponding to the left eye image is incident on the pupil of the left eye of the user, and determines the emission position of the image light corresponding to the right eye image so that the image light corresponding to the right eye image is incident on the pupil of the right eye of the user.

[0022] Then, the control unit 30 determines the folding position from which the image light is emitted from the folding hologram element 42 based on the emission position of the image light from the emission surface 50S of the light guide unit 50. Furthermore, the control unit 30 determines the incident position where the image light is incident on the incident hologram element 41 for each of the image light corresponding to the left eye image and the image light corresponding to the right eye image, based on the return position.

[0023] Then, the control unit 30 performs adjustment so that the image light (image light corresponding to the image for the left eye and image light corresponding to the image for the right eye) emitted by the image light emitting unit 10 is incident on the determined incident position. The control unit 30 can also adjust the position where the image light is incident on the hologram element 40 according to the positions of both eyes of the user, and control the image light emitting unit 10 to change the image for the left eye and the image for the right eye. The specific configuration of the control unit 30 will be described below.

[0024] FIG. 3 is a diagram illustrating an example of a hardware configuration of the control unit 30. As shown in FIG. In this embodiment, the control unit 30 is configured as a so-called computer device. 3, the control unit 30 includes a processor 301, a ROM (Read Only Memory) 302, a RAM (Random Access Memory) 303, a device I / F (Interface) unit 304, and a bus 305. Note that the hardware elements of the control unit 30 are not limited to the configuration exemplified in FIG. 3, and the control unit 30 may further include other hardware elements.

[0025] The processor 301 is, for example, a CPU (Central Processing Unit). The processor 301 executes a program to comprehensively control the operation of the control unit 30 and realize various functions of the control unit 30. The various functions of the control unit 30 will be described later.

[0026] The ROM 302 is a non-volatile memory, and stores various types of information including the programs executed by the processor 301. The RAM 303 is a volatile memory that has a working area for the processor 301 . The device I / F unit 304 is an interface for connecting to an external device (for example, the image light emitting unit 10, the imaging unit 60, etc.). The bus 305 connects the processor 301, the ROM 302, the RAM 303, and the device I / F unit 304 so that they can communicate with each other.

[0027] Fig. 4 is a diagram showing an example of functions of the control unit 30. Note that, in the example of Fig. 4, only functions necessary for explaining the main parts of the present embodiment are illustrated, but the functions of the control unit 30 are not limited to these.

[0028] 4, the control unit 30 has an eye position identifying unit 310, an exit position determining unit 311, a turn-back position determining unit 312, an entrance position determining unit 313, an entrance position adjusting unit 314, and an image light change control unit 315. In this embodiment, the processor 301 executes a program stored in the ROM 302 to realize the functions of the eye position identifying unit 310, the exit position determining unit 311, the turn-back position determining unit 312, the entrance position determining unit 313, the entrance position adjusting unit 314, and the image light change control unit 315. However, without being limited thereto, a part or all of these functions may be realized by a dedicated hardware circuit (such as a semiconductor integrated circuit).

[0029] The eye position identifying unit 310 identifies the positions of the user's eyes based on the captured image captured by the imaging unit 60. More specifically, the eye position identifying unit 310 measures the coordinates of the pupil positions of the right eye and the left eye as right eye coordinates PRe and left eye coordinates PLe by eye tracking using the imaging unit 60. In the example of Fig. 5, the right eye coordinates PRe = (x1, y1, z1) and the left eye coordinates PLe = (x2, y2, z2).

[0030] The exit position determining section 311 determines the exit position from which the image light is emitted from the exit hologram element 43 based on the positions of the user's eyes identified by the eye position identifying section 310 .

[0031] FIG. 5 is a schematic diagram for explaining the control by the control unit of the embodiment. In the example of Figure 5, the position on the xy plane of the right eye coordinate PRe and the left eye coordinate PLe is assumed to be the emission position, and the right eye coordinate PRe and the left eye coordinate PLe are assumed to exist on an extension line extending from the emission position in the z-axis direction.

[0032] 5, the right eye emission position PRo=(x1, y1) and the left eye emission position PLo=(x2, y2). Light is emitted from the right eye emission position PRo toward the right eye coordinate PRe, and light is emitted from the left eye emission position PLo toward the left eye coordinate PLe, so that light reaches both eyes of the user.

[0033] The turn-back position determination unit 312 shown in FIG. 4 determines the turn-back positions (right eye turn-back position PRt and left eye turn-back position PLt) from which the image light is emitted from the folded hologram element 42, based on the emission positions (right eye emission position PRO and left eye emission position PLo) determined by the emission position determination unit 311. In the example of FIG. 5, it is assumed that light emitted from the right eye folding position of the folding hologram element 42 to the emission hologram element 43 is repeatedly totally reflected inside the light guiding section 50 and reaches the right eye emission position PRO. In addition, the light emitted from the left eye folding position of the folding hologram element 42 to the emission hologram element 43 passes through the emission hologram element 43 inside the light guiding section 50, and reaches the left eye emission position PLo of the emission hologram element 43 while repeatedly undergoing total reflection.

[0034] In other words, the right eye exit position PRo = (x1, y1) is the position where the light emitted from the right eye folding position PRt of the folding hologram element 42 to the exit hologram element 43 reaches the exit hologram element 43 after repeated total reflection in the light propagation direction (y direction). Here, the right eye turning position PRt can be expressed as PRt = (x1, y1 + α1), where α1 is the distance corresponding to the total number of reflections of the image light for the right eye from when it is emitted from the folded hologram element 42 until it reaches the right eye turning position PRt (four times in the example of FIG. 5). Similarly, the left eye exit position PLo=(x2, y2) is the position where the light emitted from the left eye folding position PLt of the folding hologram element 42 to the exit hologram element 43 arrives after repeated total reflection in the light propagation direction (y direction). Here, the left eye turning position PLt can be expressed as (x2, y2 + β1), where β1 is the distance corresponding to the total number of reflections of the left eye image light from when it is emitted from the folded hologram element 42 until it reaches the left eye turning position PLt (four times in the example of FIG. 5).

[0035] The incident position determining section 313 shown in FIG. 4 determines the incident position at which the image light is incident on the incident hologram element 41, based on the turn-back position determined by the turn-back position determining section 312. 5, it is assumed that light emitted from the right-eye entrance position PRi of the entrance hologram element 41 to the folded hologram element 42 reaches the right-eye turning position PRt while repeatedly being totally reflected inside the light guiding section 50. It is also assumed that light emitted from the left-eye entrance position of the entrance hologram element 41 to the folded hologram element 42 reaches the left-eye turning position PLt while repeatedly being totally reflected inside the light guiding section 50.

[0036] That is, the right eye turning position PRt=(x1, y1+α1) is the position where the light emitted from the right eye entrance position PRi of the entrance hologram element 41 to the turning hologram element 42 reaches after repeated total reflection in the light propagation direction (x direction), and can be expressed as the right eye entrance position PRi=(x1+α2, y1+α1). Here, α2 is the distance corresponding to the total number of reflections of the right eye image light from leaving the entrance hologram element 41 to the right eye turning position PRt (2 times in the example of FIG. 5).

[0037] Similarly, the left eye turning position PLt=(x2, y2+β1) is the position where the light emitted from the left eye entrance position of the entrance hologram element 41 to the turning hologram element 42 reaches after repeated total reflection in the light propagation direction (x direction), and can be expressed as the left eye entrance position PLi=(x2+β2, y2+β1). Here, β2 is the distance corresponding to the total number of reflections of the left eye image light from leaving the entrance hologram element 41 to the left eye turning position PLt (2 times in the example of FIG. 5).

[0038] Here, if the thickness of light guiding section 50 (the size in the z direction in the example of Figure 5) is d and the diffraction angle of entrance hologram element 41 is θ, the incidence condition of light to entrance hologram element 41 is expressed by Equation 1 shown below. d / 2=d', c=d' / tan θ (Equation 1)

[0039] From the above-mentioned incidence conditions, it can be considered that the right eye turning position PRt is a position shifted in the x direction by c×4×n (n: natural number) from the right eye incidence position PRi (α2=-c×4×n). Similarly, the left eye turning position PLt can be considered to be a position shifted in the x direction by c×4×n from the left eye entrance position PLi (β2=-c×4×n). If n cannot be expressed as a natural number, the right eye entrance position PRi and the left eye entrance position PLi may be adjusted so that it becomes a natural number.

[0040] Continuing the description, returning to Fig. 4, the incident position adjustment section 314 performs adjustment so that the image light emitted by the image light emission section 10 is incident on the incident positions PRi, PLi determined by the incident position determination section 313.

[0041] For example, when the image light emitting unit 10 is a small display device, the incident position of the image light with respect to the incident hologram element 41 can be adjusted by changing the display positions of the right-eye image and the left-eye image displayed on the small display device. Also, for example, the incident position of the image light with respect to the incident hologram element 41 can be adjusted by moving the small display device without changing the display position of the image on the small display device.

[0042] Furthermore, the image light emitting unit 10 may be, for example, a projector such as an LCOS (Liquid crystal on silicon) using a laser light source, and may adjust the emission direction of the image light emitted from the projector so that the image light is incident on the incident positions PRi, PLi of the incident hologram element 41. Furthermore, the image light emitting unit 10 may be in a form that generates right-eye images and left-eye images using, for example, a CGH (Computer-Generated Hologram) technique, and may adjust the emission direction of the image light so that the image light generated using the CGH is incident on the incident position of the incident hologram element 41.

[0043] The image light modification control unit 315 controls the image light emitting unit 10 to modify the left eye image and the right eye image according to the positions of the user's eyes identified by the eye position identifying unit 310. Note that, for example, the image light modification control unit 315 may not be provided.

[0044] As described above, the display device 1 of this embodiment adjusts the position at which the image light enters the hologram element 40 so that the image light emitted from the image light emitting unit 10 is directed to both eyes in accordance with the positions of the user's eyes, and can therefore appropriately display a three-dimensional virtual image even if the positions of the user's eyes change.

[0045] Although the embodiments of the present disclosure have been described above, the above-mentioned embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These novel embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims.

[0046] Furthermore, the effects of the embodiments described in this specification are merely examples and are not limiting, and other effects may also be obtained.

[0047] Modifications will be described below.

[0048] (1) First Modification For example, as shown in FIG. 6, the light guiding section 50 may have a configuration including a light blocking member 70 and a light blocking member 80. In the configuration shown in FIG. The light blocking member 70 has a plurality of regions 71, 72 that can transition between a light transmitting state and a light blocking state. The region 71 corresponds to the user A (corresponding to both eyes of the user A), and the region 72 corresponds to the user B (corresponding to both eyes of the user B). The setting positions of these regions 71, 72 can be changed according to the positions of the corresponding users' eyes. This light blocking member 70 is disposed on the exit surface side of the exit hologram element 43 .

[0049] Similarly, light blocking member 80 also has multiple regions 81, 82 that can transition between a light transmitting state and a light blocking state. Region 81 corresponds to user A (corresponding to both eyes of user A), and region 82 corresponds to user B (corresponding to both eyes of user B). Light blocking member 80 is disposed between folded hologram element 42 and emission hologram element 43.

[0050] In the embodiment of FIG. 6, the control unit 30 controls the light shielding member 70 so that a plurality of regions 71, 72 on the light shielding member 70 corresponding to a plurality of users one-to-one are in a state of transmitting light in a time-division manner. More specifically, when the user A is to view a three-dimensional virtual image, the control unit 30 controls the light shielding member 70 so that the region 71 on the light shielding member 70 corresponding to the user A is in a state of transmitting light and the region 72 corresponding to the user B is in a state of not transmitting light, and controls the image light emitting unit 10 so as to emit a right-eye image and a left-eye image according to the positions of both eyes of the user A. On the other hand, when the user B is to view a three-dimensional virtual image, the control unit 30 controls the light shielding member 70 so that the region 72 on the light shielding member 70 corresponding to the user B is in a state of transmitting light and the region 71 corresponding to the user A is in a state of not transmitting light, and controls the image light emitting unit 10 so as to emit a right-eye image and a left-eye image according to the positions of both eyes of the user B.

[0051] Similarly, in the embodiment of FIG. 6, the control unit 30 controls the light shielding member 80 so that a plurality of regions 81, 82 on the light shielding member 80 corresponding to a plurality of users one-to-one are in a state of transmitting light in a time-division manner. More specifically, when the user A is to view a three-dimensional virtual image, the control unit 30 controls the light shielding member 80 so that the region 81 corresponding to the user A on the light shielding member 80 is in a state of transmitting light and the region 82 corresponding to the user B is in a state of not transmitting light, and controls the image light output unit 10 so as to output a right-eye image and a left-eye image according to the positions of both eyes of the user A. On the other hand, when the user B is to view a three-dimensional virtual image, the control unit 30 controls the light shielding member 80 so that the region 82 corresponding to the user B on the light shielding member 80 is in a state of transmitting light and the region 81 corresponding to the user A is in a state of not transmitting light, and controls the image light output unit 10 so as to output a right-eye image and a left-eye image according to the positions of both eyes of the user B.

[0052] In this manner, the control unit 30 controls the light-shielding member so that multiple regions on the light-shielding member, which correspond one-to-one with multiple users, are in a state where they transmit light in a time-division manner, and controls the image light emitting unit 10 so that image light for each user (image light corresponding to the position of both users' eyes) is also emitted in a time-division manner, thereby preventing crosstalk in which one eye is exposed to the image of the other eye.

[0053] (2) Second Modification In the entrance hologram element 41, the size of the entrance area (entrance surface) indicating the area where the image light is incident is desirably at least equal to or larger than the size of the right and left eyes. If the size of the entrance surface is smaller than the size of the right and left eyes, multiple image lights may enter the pupil, causing crosstalk.

[0054] (3) Third Modification For example, the propagation distance indicating the distance between the image lights emitted from the exit surface of the light-guiding unit 50 may be set to a value that does not cause crosstalk, depending on the interpupillary distance indicating the distance between the pupils of the user's right eye and left eye.

[0055] FIG. 7 is a diagram for explaining the propagation distance. As shown in FIG. 7, for example, the propagation distance LP can be considered to be the distance in the propagation direction (the direction in which the light travels by repeated total reflection inside the light-guiding section 50) between the image light that is diffracted by the output hologram element 43 and output from the output surface.

[0056] FIG. 8 is a diagram showing the relationship between the interpupillary distance and the propagation distance. For example, assuming that the interpupillary distance is 60 to 70 mm, the propagation distance is set to a value greater than 35 mm and less than 60 mm. Also, for example, if the interpupillary distance is assumed to be 50 to 80 mm, the propagation distance is set to a value greater than 40 mm and smaller than 50 mm. FIG. 8(A) is an example where the interpupillary distance IPD1=50 mm, FIG. 8(B) is an example where the interpupillary distance IPD2=65 mm, and FIG. 8(C) is an example where the interpupillary distance IPD3=80 mm.

[0057] Here, the propagation distance LP is determined according to the thickness d of the light-guiding section 50. More specifically, in light-guiding sections 50 made of the same material and having the same critical angle of total reflection, the propagation distance LP becomes shorter as the thickness d of the light-guiding section 50 becomes smaller, and the propagation distance LP becomes longer as the thickness d of the light-guiding section 50 becomes larger. Therefore, since the interpupillary distance is generally said to be 60 to 70 mm, as described above, the occurrence of crosstalk can be suppressed by setting the propagation distance LP to a value greater than 35 mm and less than 60 mm. Also, assuming that the interpupillary distance is less than 60 mm or greater than 70 mm and the interpupillary distance is 50 to 80 mm, the occurrence of crosstalk can be more reliably suppressed by setting the propagation distance LP to a value greater than 40 mm and less than 50 mm.

[0058] As described above, when the interpupillary distance is 60 to 70 mm, the thickness d of the light-guiding unit 50 may be set so that the propagation distance LP is greater than 35 mm and less than 60 mm. When the interpupillary distance is 50 to 80 mm, the thickness d of the light-guiding unit 50 may be set so that the propagation distance LP is greater than 40 mm and less than 50 mm. Similarly, in other cases, the thickness of the light-guiding unit 50 is set so as to obtain a desired propagation distance.

[0059] (4) Fourth Modification For example, the light guiding section 50 may further include a reflecting member disposed in a portion facing the entrance hologram element 41 and the return hologram element 42 .

[0060] FIG. 9 is a schematic diagram for explaining a form in which a mirror coat is disposed on a light guiding section. 9, light guiding section 50 may have a configuration in which a mirror coat (one example of a "reflective member") MC is arranged in an area on exit surface side 41T of two areas facing incident hologram element 41, and a mirror coat MC is arranged in each of two areas 42T, 42B (an area on the exit surface side and an area on the opposite side to the exit surface) facing folded hologram element 42. In the above-mentioned embodiment in which mirror coat MC is not provided, the propagation angle of image light in the part of light guiding section 50 where incident hologram element 41 and folded hologram element 42 are provided is assumed to be the total reflection angle, but by providing mirror coat MC as described above, the propagation angle of image light in the part of light guiding section 50 where the mirror coat is provided can be any angle other than the total reflection angle.

[0061] In this case, if the propagation angle of the image light in the portion of the light-guiding section 50 where the mirror coat is arranged is θ1, and the propagation angle of the image light in the portion of the light-guiding section 50 where the mirror coat is not arranged is θ2 (= the propagation angle at the time of total reflection), then, for example, θ1 may be greater than θ2. In other words, the angle can be set to any angle without being affected by the value of the critical angle of total reflection of the light guiding section 50 in the portion where the mirror coat is not disposed.

[0062] (5) Fifth Modification For example, based on the frequency of eye movement predicted depending on the viewing purpose, it is also possible to configure the left eye image light area and the right eye image light area corresponding to the incident image light to be emitted in an expanded exit area on the exit surface of the exit hologram element and rotated at a predetermined angle.

[0063] Japanese Patent Application Laid-Open No. 2011-180178 discloses making image light incident at a steep angle to a user, and making image light incident at a shallow angle. Based on this disclosure, the inventor came up with the idea of ​​configuring the left eye image light area and right eye image light area corresponding to the incident image light to be output in a state rotated by a predetermined angle on the exit surface of the exit hologram element, based on the predicted frequency of eye movement depending on the viewing application.

[0064] FIG. 10 is a schematic diagram for explaining the control by the control unit of the modified example. As shown in Fig. 10, the image light emitted from the emission hologram element 43 has a left-eye image light region AGL and a right-eye image light region AGR having a predetermined size on the emission surface 50S of the light guide 20 (light guide section 50). Specifically, by making the image light having a predetermined size incident on the entrance hologram element 41 from the image light emission section 10, the left-eye image light region AGL and the right-eye image light region AGR are displayed in a predetermined size on the emission surface 50S according to the predetermined size. In addition, by setting the predetermined size so that the left-eye image light region and the right-eye image light region of the predetermined size are displayed continuously with the left-eye image light region and the right-eye image light region formed by being emitted from the adjacent emission positions, the left-eye image light region AGL and the right-eye image light region AGR are enlarged on the emission surface 50S.

[0065] FIG. 11 is a diagram for explaining the principle of changing the output angle depending on the viewing purpose. As shown in FIG. 11, assuming that a virtual plane PLN1 parallel to the exit surface 50S of the light guide section 50 is placed in front of the user's face, the exit hologram element 43 is configured to emit the light rotated by a predetermined angle β on the exit surface of the exit hologram element 43 so that the left eye image light area AGL and the right eye image light area AGR corresponding to the incident image light are rotated by a predetermined angle β.

[0066] FIG. 12 is a diagram for explaining a mode in which the output angle is changed depending on the viewing purpose. For example, when viewing a vertically long display, if the predicted frequency of eye movement is greater in the vertical direction (y direction when viewed from the exit surface 50S of the light guide 50), than in the horizontal direction (x direction when viewed from the exit surface 50S of the light guide 50), then by setting the rotation angle β1 on the exit surface of the exit hologram element 43 to a value smaller than 45° (β1<45°), as shown in FIG. 11(A), the position of the user's pupils is less likely to move out of the corresponding image light areas AGL, AGR even if the eyes move in the vertical direction, and the control unit 30 can suppress the frequency of switching between the left eye image and the right eye image.

[0067] Furthermore, for example, if the predicted frequency of eye movement of the user is approximately equal in the horizontal and vertical directions, by setting the rotation angle β2 on the exit surface of the exit hologram element 43 to 45° (or β2 ≒ 45°), as shown in (B) of Figure 11, even if the eyes move in the vertical direction, the position of the user's pupils is less likely to move out of the corresponding image light areas AGL, AGR, and the control unit 30 can suppress the frequency of switching between images for the left eye and images for the right eye.

[0068] Furthermore, for example, if the user's predicted eye movement is more frequent in the horizontal direction than in the vertical direction, by setting the rotation angle β1 on the exit surface of the exit hologram element 43 to a value greater than 45° (β3>45°), as shown in (C) of Figure 11, the position of the user's pupils is less likely to move out of the corresponding image light areas AGL, AGR even if the eyes move horizontally, and the control unit 30 can suppress the frequency of switching between the left eye image and the right eye image.

[0069] (6) Sixth Modification In the above explanation, an output image at one output position PRo, PLo of output hologram element 43 corresponding to the position of the user's eyes has been described, but the same image is output from multiple output positions of output hologram element 43.

[0070] Therefore, in the sixth variant, the emission hologram element 43 is configured so that an emission image at the emission position of the emission hologram element corresponding to the position of the user's eyes and an emission image at an emission position adjacent to the emission position are continuously emitted on the emission surface 50S of the light guide 20 (light guide section 50).

[0071] That is, for example, the size of the image light incident from the image light emitting unit 10 to the input hologram element 41 is set so that an image light area for the right eye formed by emission from the emission position of the output hologram element 43 corresponding to the position of the user's right eye and another image light area for the right eye formed by emission from an emission position adjacent to the output position are displayed continuously.

[0072] Figure 13 is a diagram for explaining the principle of a configuration in which an emission image at the emission position of the emission hologram element 43 corresponding to the position of the user's eyes and an emission image at an emission position adjacent to the emission position are emitted continuously from the emission surface 50S of the light guide 20 (light guide section 50).

[0073] As shown in Figure 13, if we assume that a virtual plane PLN1 parallel to the exit surface 50S of the light guide (light guide section) is placed in front of the user's face, a right-eye image light area AGR1 corresponding to the exit image at the exit position of the exit hologram element corresponding to the position of the user's eyes and a right-eye image light area AGR2 corresponding to the exit image at the exit position adjacent to the exit position of the exit hologram element corresponding to the position of the user's eyes are emitted continuously from the exit surface of the light guide (light guide section).

[0074] Therefore, this is effectively equivalent to the right-eye image light region AGR (=AGR1+AGR2) being expanded, and the control unit 30 can suppress the frequency of switching the right-eye image.

[0075] Similarly, the left eye image light area AGL1 corresponding to the output image at the output position of the output hologram element corresponding to the position of the user's eye, and the left eye image light area AGL2 corresponding to the output image at the output position adjacent to the output position of the output hologram element corresponding to the position of the user's eye, are emitted continuously from the output surface of the light guide (light guide section), which is effectively equivalent to the left eye image light area AGL (= AGL1 + AGL2) being expanded, and the frequency of switching of the left eye image can be suppressed in the control unit 30.

[0076] As a result, the position of the user's pupil is less likely to deviate from the corresponding left eye image light area AGL and right eye image light area AGR, and the control unit 30 can reduce the frequency of switching between the left eye image and the right eye image.

[0077] Furthermore, as in the fifth modified example, if it is assumed that a virtual plane PLN1 parallel to the exit surface 50S of the light-guiding section 50 is placed in front of the user's face, it is also possible to configure the exit hologram element 43 so that the left eye image light area AGL and the right eye image light area AGR corresponding to the incident image light are rotated by a predetermined angle β on the exit surface of the exit hologram element 43. According to this configuration, in addition to the effects of the sixth modification, the effects of the fifth modification can be obtained.

[0078] (7) Seventh Modification In addition, in the above-described embodiment, an example was shown in which the incident hologram element 41, the folded hologram element 42 and the exit hologram element 43 are transmission holograms that transmit and diffract light, but the incident hologram element 41, the folded hologram element 42 and the exit hologram element 43 can also be configured as reflection holograms that reflect and diffract light.

[0079] The above-described embodiment can be arbitrarily combined with the above-described modified examples, and the above-described modified examples may be arbitrarily combined with each other. Moreover, the display device 1 according to the above-described embodiment can also be used as a head-mounted display, a glasses-type display, or the like.

[0080] (Additional Note) The above description of the embodiment discloses the following technical aspects. [First aspect] an image light emitting unit that emits image light for a left eye image and a right eye image; a light guide having an exit surface that emits light incident from the image light exit portion; A control unit that controls the image light output unit, The light guide is a hologram element into which the image light emitted from the image light emitting portion is incident; a light guiding section including the hologram element; The control unit is Identifying the positions of the user's eyes based on an image captured by an imaging unit that captures an image of the user's eyes; adjusting a position at which the image light is incident on the hologram element according to the positions of both eyes of the user; Display device. [Second aspect] the control unit adjusts a position where the image light is incident on the hologram element in accordance with the positions of both eyes of the user, and controls the image light output unit to change the image for the left eye and the image for the right eye. The display device according to the first aspect. [Third aspect] the hologram element includes an entrance hologram element on which the image light is incident, a folding hologram element on which the image light emitted from the entrance hologram element is incident, and an exit hologram element on which the image light emitted from the folding hologram element is incident and which emits the image light from the exit surface, The display device according to the first or second aspect. [Fourth aspect] The control unit determines an exit position from which the image light exits from the exit hologram element based on the positions of both eyes of the user, determines a return position from which the image light exits from the return hologram element based on the exit position, and determines an entrance position from which the image light enters the entrance hologram element based on the return position. The display device according to a third embodiment. [Fifth aspect] The light guide section includes a light blocking member having a plurality of regions each capable of transitioning between a light transmitting state and a light blocking state. The display device according to any one of the first to fourth aspects. [Sixth aspect] the light blocking member is disposed on at least one of the exit surface side of the exit hologram element and between the return hologram element and the exit hologram element. The display device according to a third embodiment. [Seventh aspect] The control unit is Detecting the positions of both eyes of each of the plurality of users based on images captured by an imaging unit that captures images of both eyes of the plurality of users; determining an exit position from which the image light is emitted from the exit hologram element based on the positions of both eyes of each of the plurality of users, determining a return position from which the image light is emitted from the return hologram element based on the exit position, and determining a position at which the image light is incident on the entrance hologram element based on the return position; controlling the light blocking member so that a plurality of regions on the light blocking member corresponding one-to-one to the plurality of users are in a state in which light is transmitted in a time-division manner; The display device according to a fifth embodiment. [Eighth aspect] a propagation distance indicating an interval between the image lights emitted from the emission surface is set to a value that does not cause crosstalk according to an interpupillary distance indicating a distance between the pupils of the right eye and the left eye of the user; The display device according to any one of the first to seventh aspects. [Ninth aspect] A propagation distance indicating an interval between the image lights emitted from the emission surface is set to a value greater than 35 mm and smaller than 60 mm. The display device according to any one of the first to eighth aspects. [Tenth aspect] the image light emitted from the emission hologram element has a left-eye image light region and a right-eye image light region, the output hologram element outputs the image light by expanding the left eye image light region and the right eye image light region so that the left eye image light region and the right eye image light region can absorb a predetermined range of movement of the corresponding eyes; The display device according to any one of the third, fourth, and sixth aspects. [Eleventh aspect] the emission hologram element emits the image light such that an emission image at an emission position of the emission hologram element corresponding to the position of the user's eyes and an emission image at an emission position adjacent to the emission position of the emission hologram element corresponding to the position of the user's eyes are continuously arranged on the emission surface of the light guide. The display device according to a tenth aspect. [12th aspect] the image light emitted from the emission hologram element has a left-eye image light region and a right-eye image light region, the emission hologram element emits the image light in a state in which the left-eye image light region and the right-eye image light region corresponding to the incident image light are inclined at a predetermined angle on the emission surface of the light guide with respect to a direction perpendicular to a left-right direction of a moving body on which the display device is mounted. The display device according to any one of the third, fourth, and sixth aspects. [13th aspect] the emission hologram element emits the image light such that an emission image at an emission position of the emission hologram element corresponding to the position of the user's eyes and an emission image at an emission position adjacent to the emission position of the emission hologram element corresponding to the position of the user's eyes are continuous on the emission surface of the light guide; The display device according to a twelfth aspect. [14th aspect] The light guide unit further includes a reflecting member disposed in a portion facing the input hologram element and the return hologram element. The display device according to any one of the third, fourth, and sixth aspects. [15th aspect] the entrance hologram element, the return hologram element and the exit hologram element are each constituted by a transmission type hologram element or a reflection type hologram element, The display device according to any one of the third, fourth, and sixth aspects. [Explanation of symbols]

[0081] 1 Display device 10 Image light emitting section 20 Light guide 30 Control section 40 Hologram element 41 Incident hologram element 42 Folded hologram element 43 Output hologram element 50 Light guide section 60 Imaging unit 301 Processor 302 ROM 303 RAM 304 Equipment I / F section 310 Both eyes position identification part 311 Output position determination unit 312 Turn-back position determination unit 313 Incident position determination unit 314 Incident position adjustment section 315 Image light change control section

Claims

1. an image light emitting unit that emits image light for a left eye image and a right eye image; a light guide having an exit surface that emits light incident from the image light exit portion; A control unit that controls the image light output unit, The light guide is a hologram element into which the image light emitted from the image light emitting portion is incident; a light guiding section including the hologram element; The control unit is Identifying the positions of the user's eyes based on an image captured by an imaging unit that captures an image of the user's eyes; adjusting a position at which the image light is incident on the hologram element according to the positions of both eyes of the user; Display device.

2. the control unit adjusts a position where the image light is incident on the hologram element in accordance with the positions of both eyes of the user, and controls the image light output unit to change the image for the left eye and the image for the right eye. The display device according to claim 1 .

3. the hologram element includes an entrance hologram element on which the image light is incident, a folding hologram element on which the image light emitted from the entrance hologram element is incident, and an exit hologram element on which the image light emitted from the folding hologram element is incident and which emits the image light from the exit surface, The display device according to claim 1 .

4. The control unit determines an exit position from which the image light exits from the exit hologram element based on the positions of both eyes of the user, determines a return position from which the image light exits from the return hologram element based on the exit position, and determines an entrance position from which the image light enters the entrance hologram element based on the return position. The display device according to claim 3 .

5. The light guide section includes a light blocking member having a plurality of regions each capable of transitioning between a light transmitting state and a light blocking state. The display device according to claim 3 .

6. the light blocking member is disposed on at least one of the exit surface side of the exit hologram element and between the return hologram element and the exit hologram element. The display device according to claim 5 .

7. The control unit is Detecting the positions of both eyes of each of the plurality of users based on images captured by an imaging unit that captures images of both eyes of the plurality of users; determining an exit position from which the image light is emitted from the exit hologram element based on the positions of both eyes of each of the plurality of users, determining a return position from which the image light is emitted from the return hologram element based on the exit position, and determining a position at which the image light is incident on the entrance hologram element based on the return position; controlling the light blocking member so that a plurality of regions on the light blocking member corresponding one-to-one to the plurality of users are in a state in which light is transmitted in a time-division manner; The display device according to claim 5 .

8. a propagation distance indicating an interval between the image lights emitted from the emission surface is set to a value that does not cause crosstalk according to an interpupillary distance indicating a distance between the pupils of the right eye and the left eye of the user; The display device according to claim 1 .

9. A propagation distance indicating an interval between the image lights emitted from the emission surface is set to a value greater than 35 mm and smaller than 60 mm. The display device according to claim 1 .

10. the image light emitted from the emission hologram element has a left-eye image light region and a right-eye image light region, the output hologram element outputs the image light by expanding the left eye image light region and the right eye image light region so that the left eye image light region and the right eye image light region can absorb a predetermined range of movement of the corresponding eyes; The display device according to claim 3 .

11. the emission hologram element emits the image light such that an emission image at an emission position of the emission hologram element corresponding to the position of the user's eyes and an emission image at an emission position adjacent to the emission position of the emission hologram element corresponding to the position of the user's eyes are continuously arranged on the emission surface of the light guide. The display device according to claim 10.

12. the image light emitted from the emission hologram element has a left-eye image light region and a right-eye image light region, the emission hologram element emits the image light in a state in which the left-eye image light region and the right-eye image light region corresponding to the incident image light are inclined at a predetermined angle on the emission surface of the light guide with respect to a direction perpendicular to a left-right direction of a moving body on which the display device is mounted. The display device according to claim 3 .

13. the emission hologram element emits the image light such that an emission image at an emission position of the emission hologram element corresponding to the position of the user's eyes and an emission image at an emission position adjacent to the emission position of the emission hologram element corresponding to the position of the user's eyes are continuous on the emission surface of the light guide; The display device according to claim 12.

14. The light guide unit further includes a reflecting member disposed in a portion facing the input hologram element and the return hologram element. The display device according to claim 3 .

Images