Sony Patent | Display apparatus

Patent: Display apparatus

Drawings: Click to check drawins

Publication Number: 20210026141

Publication Date: 20210128

Applicant: Sony Semiconductor Solutions Corporation

Assignee: Sony

Abstract

A display apparatus that can surely make an image reach an observer’s pupil without imposing a burden on the observer. The apparatus includes: an eyepiece optical system; and an image display apparatus including an image forming apparatus and a transfer optical system. The eyepiece optical system and the image display apparatus are spatially separated from each other, the eyepiece optical system forms an image from the transfer optical system on a retina of an observer, the image display apparatus further includes a first position detection apparatus that detects a position of the eyepiece optical system, a second position detection apparatus that detects a position of a pupil of the observer. On the basis of detected positional information of the eyepiece optical system and the pupil, the transfer optical system is controlled such that the image incident from the image forming apparatus reaches the eyepiece optical system.

Claims

1. A display apparatus comprising: an eyepiece optical system; and an image display apparatus including an image forming apparatus and a transfer optical system that emits an image incident from the image forming apparatus to the eyepiece optical system, wherein the eyepiece optical system and the image display apparatus are arranged to be spatially separated from each other, the eyepiece optical system forms an image from the transfer optical system on a retina of an observer, the image display apparatus further includes a first position detection apparatus that detects a position of the eyepiece optical system, a second position detection apparatus that detects a position of a pupil of the observer, and a transfer optical system controlling apparatus, and on a basis of positional information of the eyepiece optical system detected by the first position detection apparatus and positional information of the pupil of the observer detected by the second position detection apparatus, the transfer optical system controlling apparatus controls the transfer optical system such that the image incident from the image forming apparatus reaches the eyepiece optical system.

2. The display apparatus according to claim 1, wherein the eyepiece optical system and the image display apparatus are relatively movable.

3. The display apparatus according to claim 1, wherein the eyepiece optical system is mounted on the observer.

4. The display apparatus according to claim 1, wherein the eyepiece optical system is arranged at a location distant from the observer.

5. The optical apparatus according to claim 1, wherein the transfer optical system includes a movable mirror.

6. The display apparatus according to claim 1, wherein when an angle formed by a straight line connecting a center of the eyepiece optical system and a center of the pupil of the observer and a normal line passing through the center of the eyepiece optical system is .theta..sub.1, an angle formed by a light beam emitted from a center of the image forming apparatus passing through the transfer optical system, and reaching the eyepiece optical system and a normal line passing through the center of the eyepiece optical system is .theta..sub.2, and a focal length of the eyepiece optical system is f.sub.0 (unit: mm), the transfer optical system controlling apparatus controls the transfer optical system so as to satisfy f.sub.0tan(.theta..sub.2)-tan(.theta..sub.1)|.ltoreq.3.5.

7. The display apparatus according to claim 1, wherein the second position detection apparatus includes a light emitting unit that emits infrared light and a light receiving unit that receives the infrared light reflected by the pupil of the observer, and the eyepiece optical system has a wavelength-dependent light-collecting characteristic.

8. The optical apparatus according to claim 7, wherein a retroreflective marker is attached to the eyepiece optical system.

9. The display apparatus according to claim 7, wherein the eyepiece optical system includes a hologram lens.

10. The display apparatus according to claim 1, wherein the second position detection apparatus includes a light receiving unit that receives visible light reflected by the pupil of the observer.

11. The display apparatus according to claim 10, wherein the eyepiece optical system has a wavelength-dependent light-collecting characteristic.

12. The display apparatus according to claim 1, wherein the second position detection apparatus includes a light emitting unit that emits infrared light and a light receiving unit that receives the infrared light reflected by the pupil of the observer, and the eyepiece optical system has a wavelength-dependent diffraction characteristic.

13. The display apparatus according to claim 12, wherein the infrared light emitted from the light emitting unit is affected by the diffraction characteristic of the eyepiece optical system.

14. The display apparatus according to claim 13, wherein the eyepiece optical system includes a diffractive optical member.

15. The display apparatus according to claim 14, wherein the diffractive optical member includes a diffractive member having a diffractive function and a light collecting member having a light collecting function.

16. The display apparatus according to claim 1, wherein the eyepiece optical system includes a light collecting member on which an image from the transfer optical system is incident, and a deflection member that guides light emitted from the light collecting member to the pupil of the observer.

17. The optical apparatus according to claim 1, wherein the first position detection apparatus emits infrared light.

18. The display apparatus according to claim 1, wherein on a basis of positional information of the eyepiece optical system detected by the first position detection apparatus and positional information of the pupil of the observer detected by the second position detection apparatus, a position of an image formed in the image forming apparatus is corrected.

19. The display apparatus according to claim 1, wherein the eyepiece optical system includes a diffraction grating.

20. A display apparatus comprising: an eyepiece optical system; and an image display apparatus including an image forming apparatus and a transfer optical system that emits an image incident from the image forming apparatus to the eyepiece optical system, wherein the eyepiece optical system and the image display apparatus are arranged to be spatially separated from each other, the eyepiece optical system forms an image from the transfer optical system on a retina of an observer, the image display apparatus further includes a first position detection apparatus that detects a position of the eyepiece optical system, a second position detection apparatus that detects a position of a pupil of the observer, and a transfer optical system controlling apparatus, and the second position detection apparatus is arranged at a position where the pupil of the observer can be seen.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a display apparatus.

BACKGROUND ART

[0002] A head-mounted image display apparatus mounted on an observer’s head is known from, for example, Japanese Patent Application Laid-Open No. 2005-309264. The image display apparatus 1 disclosed in this patent publication includes a head mounting unit 6 mounted on an observer’s head and a body carrying unit 7 carried by the observer’s body. The head mounting unit 6 is provided with a convex lens 8 constituting a transfer optical system 5, and a part of an azimuth and distance detection system. The head mounting unit 6 includes a light emitting unit R including an infrared LED, an actuator 27 for moving the convex lens 8, and a drive circuit 28.

CITATION LIST

Patent Document

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-309264

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

[0004] By the way, in the technique disclosed in the above-mentioned patent publication, the light emitting unit R provided in the head mounting unit 6, the actuator 27, and the drive circuit 28 require a power source (battery). Therefore, it is a structure in which a burden is imposed on the observer, such as an increase in the mass and size of the head mounting unit 6. In a case where it is assumed that the light emitting unit R, the actuator 27, and the drive circuit 28 are removed and only the convex lens 8 is mounted on the head mounting unit 6, when the observer moves, the positional relationship between the body carrying unit, the head mounting unit, and the pupil of the observer is broken, and a projected image deviates from the observer’s pupil. As a result, a problem that it becomes difficult to observe the image occurs. Furthermore, in this image display apparatus, it is premised that the positions of the head mounting unit and the observer’s pupil are properly aligned. However, in the practical use of the image display apparatus, due to the position error during initial adjustment, the change over time during use (misalignment of the head mounting unit 6), the position reproducibility when attaching and detaching the head mounting unit 6, and the like, it is difficult to always maintain the state of the positional relationship in which the head mounting unit 6 matches and the observer’s pupil. Then, due to the above reasons, there arises a problem that the projected image does not surely reach the observer’s pupil.

[0005] Therefore, an object of the present disclosure is to provide a display apparatus having a configuration and a structure that can surely make an image reach an observer’s pupil without imposing a burden on the observer.

Solutions to Problems

[0006] A display apparatus according to a first aspect of the present disclosure for achieving the aforementioned object includes:

[0007] an eyepiece optical system; and

[0008] an image display apparatus including an image forming apparatus and a transfer optical system that emits an image incident from the image forming apparatus to the eyepiece optical system, in which

[0009] the eyepiece optical system and the image display apparatus are arranged to be spatially separated from each other,

[0010] the eyepiece optical system forms an image from the transfer optical system on a retina of an observer,

[0011] the image display apparatus further includes

[0012] a first position detection apparatus that detects a position of the eyepiece optical system,

[0013] a second position detection apparatus that detects a position of a pupil of the observer, and

[0014] a transfer optical system controlling apparatus, and

[0015] on the basis of positional information of the eyepiece optical system detected by the first position detection apparatus and positional information of the pupil of the observer detected by the second position detection apparatus, the transfer optical system controlling apparatus controls the transfer optical system such that the image incident from the image forming apparatus reaches the eyepiece optical system.

[0016] A display apparatus according to a second aspect of the present disclosure for achieving the aforementioned object includes:

[0017] an eyepiece optical system; and

[0018] an image display apparatus including an image forming apparatus and a transfer optical system that emits an image incident from the image forming apparatus to the eyepiece optical system, in which

[0019] the eyepiece optical system and the image display apparatus are arranged to be spatially separated from each other,

[0020] the eyepiece optical system forms an image from the transfer optical system on a retina of an observer,

[0021] the image display apparatus further includes

[0022] a first position detection apparatus that detects a position of the eyepiece optical system,

[0023] a second position detection apparatus that detects a position of a pupil of the observer, and

[0024] a transfer optical system controlling apparatus, and

[0025] the second position detection apparatus is arranged at a position where the pupil of the observer can be seen.

BRIEF DESCRIPTION OF DRAWINGS

[0026] FIGS. 1A and 1B are respectively a conceptual diagram of a display apparatus of Example 1, and a diagram showing control of a transfer optical system and an image forming apparatus on the basis of an image acquired by a first position detection apparatus (positional information of a retroreflective marker) and an image acquired by a second position detection apparatus (positional information of an observer’s pupil) in the display apparatus of Example 1.

[0027] FIGS. 2A, 2B, and 2C are conceptual diagrams of the image forming apparatus in the display apparatus of Example 1.

[0028] FIGS. 3A, 3B and 3C are diagrams schematically showing behavior of a luminous flux emitted from the transfer optical system, and a positional relationship between an eyepiece optical system and an observer’s pupil, and particularly, FIG. 3C is a diagram for explaining an angle .theta..sub.1 formed by a straight line connecting a center of the eyepiece optical system and a center of the observer’s pupil and a normal line passing through the center of the eyepiece optical system, and an angle .theta..sub.2 formed by a light beam emitted from a center of an image forming apparatus passing through the transfer optical system, and reaching the eyepiece optical system and a normal line passing through the center of the eyepiece optical system.

[0029] FIGS. 4A and 4B are a diagram schematically showing behavior of a luminous flux emitted from the transfer optical system, and a positional relationship between an eyepiece optical system and an observer’s pupil, and a diagram for explaining an angle .theta..sub.1 formed by a straight line connecting a center of the eyepiece optical system and a center of the observer’s pupil and a normal line passing through the center of the eyepiece optical system, and an angle .theta..sub.2 formed by a light beam emitted from a center of an image forming apparatus passing through the transfer optical system, and reaching the eyepiece optical system and a normal line passing through the center of the eyepiece optical system.

[0030] FIGS. 5A and 5B are conceptual diagrams of a display apparatus of Example 2 and a variation example thereof.

[0031] FIG. 6 is a conceptual diagram of a display apparatus of Example 3.

[0032] FIGS. 7A and 7B are conceptual diagrams of a display apparatus of Example 4 and a variation example thereof.

[0033] FIGS. 8A and 8B are conceptual diagrams of a display apparatus of Example 5 and a variation example thereof.

[0034] FIGS. 9A and 9B are conceptual diagrams of a display apparatus of Example 6.

[0035] FIG. 10 is a conceptual diagram of a display apparatus of Example 7.

[0036] FIGS. 11A, 11B, 11C and 11D are diagrams schematically showing behavior of a luminous flux emitted from a transfer optical system, and a positional relationship between an eyepiece optical system and an observer’s pupil in the display apparatus of Example 8.

[0037] FIGS. 12A and 12B are schematic diagrams showing a state in which the display apparatus of Example 3 is used indoors and a state in which an image forming apparatus is arranged behind a seat back.

[0038] FIG. 13A is a schematic enlarged cross-sectional view showing a part of a reflective volume hologram diffraction grating, and FIGS. 13B and 13C are a reflective blazed diffraction grating and a schematic partially cross-sectional view of a reflective blazed diffraction grating having a step shape (however, hatching lines are omitted).

[0039] FIG. 14 is a diagram for explaining a method of manufacturing a reflective volume hologram diffraction grating.

MODE FOR CARRYING OUT THE INVENTION

[0040] Hereinafter, the present disclosure will be described on the basis of Examples with reference to the drawings, but the present disclosure is not limited to the Examples. Various numerical values and materials in the Examples are examples. Note that the description is provided in the order set forth below.

[0041] 1. General description of display apparatus according to first aspect to second aspect of the present disclosure

[0042] 2. Example 1 (display apparatus according to first aspect to second aspect of the present disclosure)

[0043] 3. Example 2 (variation of Example 1)

[0044] 4. Example 3 (another variation of Example 1)

[0045] 5. Example 4 (variation of Examples 1 to 3)

[0046] 6. Example 5 (variation of Example 3)

[0047] 7. Example 6 (variation of Examples 1 to 5)

[0048] 8. Example 7 (variation of Examples 1 to 6)

[0049] 9. Example 8 (variation of Examples 1 to 7)

[0050] 10. Other

[0051]

[0052] In the display apparatus according to the first aspect of the present disclosure, on the basis of the positional information of the eyepiece optical system detected by the first position detection apparatus and the positional information of the observer’s pupil detected by the second position detection apparatus, the transfer optical system controlling apparatus controls the transfer optical system so that the image incident from the image forming apparatus reaches the eyepiece optical system. However, it may be a form in which the transfer optical system is controlled so that all the images incident from the image forming apparatus reach the eyepiece optical system, or it may be a form in which the transfer optical system is controlled so that some of the images incident from the image forming apparatus reach the eyepiece optical system. The display apparatus according to the first aspect to the second aspect of the present disclosure is a retinal projection type display apparatus based on Maxwellian view. In the following description, the display apparatus according to the first aspect of the present disclosure and the display apparatus according to the second aspect of the present disclosure may be collectively referred to as the “display apparatus of the present disclosure”.

[0053] In the display apparatus of the present disclosure including the preferable forms described above, the eyepiece optical system and the image display apparatus can be in a relatively movable form. That is, the image display apparatus is arranged at a position distant from the observer, or at a part of the observer distant from the observer’s head. In the latter case, for example, although it is not limited, the image display apparatus is mounted as a wearable device at a site distant from the observer’s head such as the observer’s wrist. Alternatively, the image display apparatus is arranged in a personal computer, or is arranged in a state of being connected to the personal computer. Alternatively, the image display apparatus is provided in an external facility or the like, as described later.

[0054] Then, in the display apparatus of the present disclosure including the preferable forms described above, the eyepiece optical system can be in a form of being mounted on the observer, or alternatively, the eyepiece optical system can be in a form of being arranged at a position distant from the observer (that is, the eyepiece optical system is not mounted on the observer).

[0055] Furthermore, in the display apparatus of the present disclosure including the preferable forms described above, the transfer optical system may be in a form of including a movable mirror. When the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) are set with respect to the observer, examples of the movable mirror include, for example, a two-dimensionally rotatable mirror or micro electro mechanical systems (MEMS) mirror that moves an image incident from the image forming apparatus in the horizontal direction and the vertical direction. Alternatively, the movable mirror includes a movable mirror that is movable in three axes.

[0056] Furthermore, in the display apparatus of the present disclosure including the preferable forms described above, when the angle formed by the straight line connecting the center of the eyepiece optical system and the center of the observer’s pupil and the normal line passing through the center of the eyepiece optical system is .theta..sub.1, the angle formed by the light beam emitted from the center of the image forming apparatus passing through the transfer optical system, and reaching the eyepiece optical system and the normal line passing through the center of the eyepiece optical system is .theta..sub.2, and the focal length of the eyepiece optical system is f.sub.0 (unit: mm), the diameter of the observer’s pupil strongly depends on the environment and the state of the observer, and is said to be 2 mm to 7 mm.

[0057] The transfer optical system controlling apparatus thus can be in a form of controlling the transfer optical system so as to satisfy

f.sub.0|tan(.theta..sub.2)-tan(.theta..sub.1)|.ltoreq.3.5,

preferably,

f.sub.0|tan(.theta..sub.2)-tan(.theta..sub.1)|.ltoreq.1,

[0058] more preferably .theta..sub.1=.theta..sub.2.

[0059] Furthermore, in the display apparatus of the present disclosure including the preferable forms described above, the second position detection apparatus includes a light emitting unit that emits infrared light, and a light receiving unit that receives the infrared light reflected by the observer’s pupil; and the eyepiece optical system can have a wavelength-dependent light-collecting characteristic, and in this case, it can be configured such that the infrared light emitted from the light emitting unit is not affected by the light-collecting characteristic of the eyepiece optical system. Then, in these cases, the eyepiece optical system can have a position display means (position detected means), specifically, a retroreflective marker attached thereto. Furthermore, in these cases, the eyepiece optical system can be configured by a hologram lens. The hologram lens can have a known configuration and structure. Note that it is preferable that the infrared light emitted from the light emitting unit be not affected by the light-collecting characteristic of the eyepiece optical system or be hardly affected by the light-collecting characteristic of the eyepiece optical system. That is, specifically, it is preferable that the infrared light emitted from the light emitting unit be not collected or be slightly collected by the hologram lens constituting the eyepiece optical system. The light emitting unit can be configured by, for example, a light emitting diode that emits infrared light or a combination of a semiconductor laser element that emits infrared light and a light diffusion plate, and the light receiving unit can be configured by an imaging apparatus (infrared camera) or a sensor (infrared sensor) that can detect infrared light. By mounting a filter (infrared transmission filter) that allows only the wavelength of infrared light used for detection to pass in front of the imaging apparatus, it is possible to simplify image processing in the subsequent stage.

[0060] Alternatively, in the display apparatus of the present disclosure including the preferable forms described above, the second position detection apparatus can include a light receiving unit that receives visible light reflected by the observer’s pupil. Specifically, the light receiving unit receives visible light that is external light (environmental light) reflected by, for example, colliding with the observer’s pupil. Then, in this case, the eyepiece optical system can have a wavelength-dependent light-collecting characteristic, and furthermore, the eyepiece optical system can have a lens member or can also have a hologram lens. Then, the second position detection apparatus can specify the position of the eyepiece optical system by performing image processing on the obtained image of the eyepiece optical system. Although the retroreflective marker is unnecessary, for example, by attaching a color marker to the eyepiece optical system, the image processing can be simplified. The light receiving unit can include an imaging apparatus or sensor capable of detecting visible light.

[0061] Alternatively, in the display apparatus of the present disclosure including the preferable forms described above, the second position detection apparatus includes a light emitting unit that emits infrared light, and a light receiving unit that receives the infrared light reflected by the observer’s pupil; and the eyepiece optical system can have a wavelength-dependent diffraction characteristic. In this case, it can be configured such that the infrared light emitted from the light emitting unit is affected by the diffraction characteristic of the eyepiece optical system and the infrared light emitted from the light emitting unit is not affected by the light-collecting characteristic of the eyepiece optical system. Then, in these cases, the eyepiece optical system can include a diffractive optical member, and the diffractive optical member is not limited, but can include a diffractive member having a diffractive function and a light collecting member having a light collecting function. Here, the diffractive member may include a transmissive volume hologram diffraction grating, and the light collecting member may include a transmissive hologram lens.

[0062] Furthermore, in the display apparatus of the present disclosure including the preferable forms and configurations described above, the eyepiece optical system can be in a form of including a light collecting member on which an image from the transfer optical system is incident, and a deflection member that guides the light emitted from the light collecting member to the observer’s pupil. The image from the transfer optical system is changed in propagation and transfer direction in the direction of the deflection member in the light collecting member. Then, the focal length f.sub.0 of the eyepiece optical system can be extended with this configuration. The light collecting member and the deflection member are not limited, but are attached to a support member, or provided on the support member integrally with the support member. The light collecting member can include a transmissive hologram lens or a reflective hologram lens, and the deflection member can include a transmissive volume hologram diffraction grating or a reflective volume hologram diffraction grating. It is also possible to adopt a form in which light that is incident on the light collecting member and emitted from the light collecting member is totally reflected once or more within the support member and then incident on the deflection member. Note that the term “total reflection” means internal total reflection or total reflection inside the support member.

[0063] In a case where the support member includes a transparent plastic material, the plastic material may be polyethylene terephthalate, polyethylene naphthalate, polycarbonate, cellulose ester such as cellulose acetate, fluorine polymer such as polyvinylidene fluoride or a copolymer of polytetrafluoroethylene and hexafluoropropylene, polyether such as polyoxymethylene, polyolefin such as polyacetal, polystyrene, polyethylene, polypropylene, methylpentene polymer, polyimide such as polyamide imide or polyether imide, polyamide, polyether sulfone, polyphenylene sulfide, polyvinylidene fluoride, tetra acetyl cellulose, brominated phenoxy, polyarylate, polysulfone, or the like. In a case where the support member includes glass, examples of the glass include transparent glasses such as soda-lime glass and white plate glass.

[0064] FIG. 13A shows a schematic enlarged cross-sectional view showing a part of a reflective volume hologram diffraction grating. Interference fringes having an inclination angle (slant angle) .phi. are formed on the reflective volume hologram diffraction grating. The inclination angle .phi. refers to the angle formed by the interference fringes with the surface of the reflective volume hologram diffraction grating. The interference fringes are formed from the inside of the reflective volume hologram diffraction grating to the surface thereof. The interference fringes satisfy the Bragg condition. The Bragg condition means a condition that satisfies the following Formula (A). In Formula (A), m is a positive integer, .lamda. is a wavelength, d is the pitch of a grating surface (distance in the normal direction of a virtual plane including interference fringes), and .THETA. is a complementary angle of the angle of incidence on the interference fringes. Furthermore, in a case where light enters the reflective volume hologram diffraction grating at incident angle .psi., the relationship between .THETA., the inclination angle .phi., and the incident angle .psi. is as shown in Formula (B).

m.lamda.=2dsin(.THETA.) (A)

.THETA.=90.degree.-(.phi.+.psi.) (B)

[0065] A photopolymer material can be mentioned as a constituent material of the volume hologram diffraction grating. The constituent material and the basic structure of the volume hologram diffraction grating are only required to be the same as the constituent material and structure of a conventional volume hologram diffraction grating. Interference fringes are formed from the inside of the volume hologram diffraction grating to the surface thereof, and a method of forming such interference fringes themselves is only required to be the same as a conventional forming method. Specifically, as shown in FIG. 14, for example, it is sufficient if a member (for example, a photopolymer material) constituting the volume hologram diffraction grating is irradiated with object light from a first predetermined direction on one side and simultaneously the member constituting the volume hologram diffraction grating is irradiated with reference light from a second predetermined direction on the other side, such that the interference fringes formed by the object light and the reference light are recorded inside the volume hologram diffraction grating. In the example shown in FIG. 14, a mirror for irradiating the photopolymer material with the reference light is inclined by 60 degrees and (60.+-.6 degrees), and the reference light is emitted to the photopolymer material three times in total. In the volume hologram diffraction grating thus obtained, the incident image can be divided into three images. By appropriately selecting the first predetermined direction, the second predetermined direction, the wavelengths of the object light and the reference light, a desired pitch of the interference fringes on the surface of the volume hologram diffraction grating and a desired inclination angle (slant angle) of the interference fringes can be obtained. The inclination angle of the interference fringe means the angle formed by the surface of the volume hologram diffraction grating and the interference fringe. In a case where the volume hologram diffraction grating includes a stack structure of volume hologram diffraction grating layers of P layer, it is sufficient if such stacking of volume hologram diffraction grating layers is manufactured such that volume hologram diffraction grating layers of P layer are separately manufactured, and then the volume hologram diffraction grating layers of P layer are stacked (adhered) using, for example, an ultraviolet curable adhesive. Furthermore, the volume hologram diffraction grating layer of P layer may be manufactured as follows. A volume hologram diffraction grating layer of one layer using a photopolymer material having an adhesive property is manufactured and then the photopolymer material having an adhesive property is sequentially bonded onto the layer to manufacture a volume hologram diffraction grating layer. Such a volume hologram diffraction grating is of a refractive index modulation type. By irradiating the manufactured volume hologram diffraction grating layer with energy rays as necessary, the monomers in the photopolymer material remaining without being polymerized when the volume hologram diffraction grating layer is irradiated with the object light and the reference light may be polymerized and fixed. If necessary, heat treatment may be performed for stabilization.

[0066] Furthermore, in the display apparatus of the present disclosure including the preferable forms and configurations described above, the first position detection apparatus may be in a form of emitting and receiving infrared light, but is not limited to this, and may be in a form of receiving visible light having a predetermined wavelength. Note that, in the former case, the light emitting unit constituting the first position detection apparatus can include, for example, a light emitting diode that emits infrared light or a combination of a semiconductor laser element that emits infrared light and a light diffusion plate, and the light receiving unit constituting the first position detection apparatus can include an imaging apparatus (infrared camera) or a sensor (infrared sensor) that can detect infrared light. By mounting a filter (infrared transmission filter) that allows only the wavelength of infrared light used for detection to pass in front of the imaging apparatus, it is possible to simplify image processing in the subsequent stage. On the other hand, in the latter case, the light receiving unit can include an imaging apparatus or sensor capable of detecting visible light. Furthermore, the light emitting unit and the light receiving unit constituting the first position detection apparatus may be in a form of being common (shared) with the light emitting unit and the light receiving unit constituting the second position detection apparatus.

[0067] Furthermore, the display apparatus of the present disclosure including the preferable forms and configurations described above can be in a form in which, on the basis of the positional information of the eyepiece optical system detected by the first position detection apparatus and the positional information of the observer’s pupil detected by the second position detection apparatus, the position of the image formed in the image forming apparatus is corrected.

[0068] Furthermore, in the display apparatus of the present disclosure including the preferable forms and configurations described above, the eyepiece optical system may be in a form of including a diffraction grating. The diffraction grating is an optical element that causes a diffraction phenomenon by a grating pattern. A plurality of images is obtained on the basis of the kth-order diffraction light emitted from the diffraction grating (however, k=0, .+-.1, .+-.2 … ). Note that when an image including parallel light is incident on the diffraction grating, the light rays constituting each of the images emitted from the diffraction grating also become parallel light.

[0069] The diffraction grating can include, but is not limited to, a transmissive diffraction grating or a transmissive hologram diffraction grating (specifically, a transmissive volume hologram diffraction grating), or a reflective diffraction grating or a reflective hologram diffraction grating (specifically, a reflective volume hologram diffraction grating). In a case where the diffraction grating includes a transmissive diffraction grating or a transmissive hologram diffraction grating, when the incident angle .psi. of the light constituting the image is constant, in order to obtain the plurality of images divided by the diffraction grating and emitted from the diffraction grating, it is necessary to change the value of .THETA. in various ways. To change the value of .THETA., it is sufficient if the value of the inclination angle .phi. is changed from Formula (B) and furthermore the value of the pitch d of the grating surface is changed from Formula (A). In other words, by appropriately selecting the value of the inclination angle .phi. and the value of the pitch d of the grating surface, the image incident on the diffraction grating including the volume hologram diffraction grating can be divided by the diffraction grating, and a plurality of images can be emitted from the diffraction grating.

[0070] Alternatively, the diffraction grating may have a well-known configuration and structure, and examples include a reflective blazed diffraction grating (see FIG. 13B) and a reflective blazed diffraction grating having a step shape (see FIG. 13C). However, the diffraction grating is not limited to these diffraction gratings. The grating pattern is configured such that, for example, linear recesses and protrusions are arranged in parallel at a cycle of a micrometer size, and the cycle, the pattern thickness (difference between recess and protrusion), or the like is appropriately selected on the basis of the wavelength range of light emitted from the image forming apparatus. The diffraction grating can be manufactured by a known method.

[0071] It is possible to adopt a form in which an image can be divided into at least two images by the diffraction grating provided in the eyepiece optical system. Specifically, for example, it is possible to exemplify a form in which the diffraction grating divides the image into three images in the horizontal direction, a form in which the diffraction grating divides the image into three images in the vertical direction, a form in which the diffraction grating divides the image into three images in the horizontal direction and three images in the vertical direction into a cross (form in which one image including the center light path overlaps and the image is divided into five images in total), a form in which the diffraction grating divides the image into two images in the horizontal direction and two images in the vertical direction, 2.times.2=4, and a form in which the diffraction grating divides the image into three images in the horizontal direction and three images in the vertical direction, 3.times.3=9.

[0072] In the display apparatus of the present disclosure including the preferable forms and configurations described above, the eyepiece optical system can be of a semi-transmissive (see-through) type, which allows the outside scene to be viewed through the eyepiece optical system. Then, in this case, the eyepiece optical system can be in a form of including a hologram lens or being provided with a hologram lens. In some cases, the eyepiece optical system may be a non-transmissive type (a form in which the outside scene cannot be viewed through the eyepiece optical system).

[0073] In the display apparatus of the present disclosure including the various preferable forms and configurations described above, the image display apparatus may be in a form of being arranged in front of the observer. Note that the image display apparatus, as long as it is arranged in front of the observer, although depending on the specifications of the transfer optical system and the eyepiece optical system, may be located higher than the observer’s head, may be located at the same level as the observer’s head, may be located lower than the observer’s head, may be located facing the observer, or may be located at an angle to the observer. In a case where the display apparatus is a non-transmissive type, the image display apparatus can be arranged in front of the observer.

[0074] In the display apparatus of the present disclosure including the various preferable forms and configurations described above, the image forming apparatus may be in a form of having a plurality pixels arranged in a two-dimensional matrix. Such a configuration of the image forming apparatus is referred to as a “first configuration image forming apparatus” for the sake of convenience.

[0075] Examples of the first configuration image forming apparatus include an image forming apparatus including a reflective spatial light modulation apparatus and a light source; an image forming apparatus including a transmissive spatial light modulation apparatus and a light source; and an image forming apparatus including a light emitting element such as organic electro luminescence (EL), an inorganic EL, a light emitting diode (LED), a semiconductor laser element. Among them, an image forming apparatus including an organic EL light emitting element (organic EL display apparatus), and an image forming apparatus including a reflective spatial light modulation apparatus and a light source are preferable. Examples of the spatial light modulation apparatus include a light valve, for example, a transmissive or reflective liquid crystal display apparatus such as liquid crystal on silicon (LCOS), a digital micromirror device (DMD), and examples of the light source include a light emitting element. Moreover, the reflective spatial light modulation apparatus includes a liquid crystal display apparatus, and a polarization beam splitter that reflects a part of the light from the light source and guides it to the liquid crystal display apparatus, and passes a part of the light reflected by the liquid crystal display apparatus and guides it to the transfer optical system. Examples of the light emitting element constituting the light source include a red light emitting element, a green light emitting element, a blue light emitting element, and a white light emitting element. Alternatively, white light may be obtained by mixing the red light, the green light, and the blue light emitted respectively from the red light emitting element, the green light emitting element, and the blue light emitting element using a light pipe to uniformize the brightness. Examples of the light emitting element include a semiconductor laser element, a solid-state laser, and an LED. It is sufficient if the number of pixels is determined on the basis of the specifications required for the image forming apparatus, and specific values of the number of pixels include 320.times.240, 432.times.240, 640.times.480, 1024.times.768, 1920.times.1080, or the like. In the first configuration image forming apparatus, the diaphragm may be in a form of being arranged at the front focal point (focal point on the image forming apparatus side) of a lens system (described later).

[0076] Alternatively, the image forming apparatus of the display apparatus of the present disclosure including the preferable forms and configurations described above may be in a form of including a light source and a scanning means that scans light emitted from the light source to form an image. Such an image forming apparatus is referred to as a “second configuration image forming apparatus” for the sake of convenience.

[0077] The light source of the second configuration image forming apparatus can include a light emitting element, specifically, a red light emitting element, a green light emitting element, a blue light emitting element, and a white light emitting element. Alternatively, white light may be obtained by mixing the red light, the green light, and the blue light emitted respectively from the red light emitting element, the green light emitting element, and the blue light emitting element with a light pipe to uniformize the brightness. Examples of the light emitting element include a semiconductor laser element, a solid-state laser, and an LED. It is sufficient if the number of pixels (virtual pixels) in the second configuration image forming apparatus is also determined on the basis of the specifications required for the image forming apparatus, and specific values of the number of pixels (virtual pixels) include 320.times.240, 432.times.240, 640.times.480, 1024.times.768, 1920.times.1080, or the like. Furthermore, in the case of displaying a color image and in a case where the light source includes a red light emitting element, a green light emitting element, and a blue light emitting element, it is preferable to perform color combination using, for example, a cross prism. The scanning means can include, for example, a MEMS mirror or a galvano mirror having a two-dimensionally rotatable micromirror that horizontally and vertically scans the light emitted from the light source. In the second configuration image forming apparatus, the MEMS mirror or the galvano mirror may be in a form of being arranged at the front focal point (focal point on the image forming apparatus side) of a lens system (described later).

[0078] In the first configuration image forming apparatus or the second configuration image forming apparatus, the light that has become a plurality of parallel light beams by a lens system (an optical system that turns emitted light into parallel light) is made to incident on the transfer optical system (specifically, for example, a movable mirror). In order to generate parallel light, specifically, as described above, for example, it is sufficient if the light emitting unit of the image forming apparatus is positioned at the location (position) of the focal length in the lens system. As the lens system, an optical system having a positive optical power as a whole including a convex lens, a concave lens, a free-form surface prism, and a hologram lens may be used alone or in combination can be exemplified. Between the lens system and the transfer optical system, a light shielding unit having an opening may be arranged in the vicinity of the lens system so that undesired light is not emitted from the lens system or incident on the transfer optical system.

[0079] In the display apparatus of the present disclosure, the eyepiece optical system may be in a form of being attached to the frame. The frame includes a front portion arranged in front of the observer, two temple portions rotatably attached to both ends of the front portion via hinges, and a nose pad. A tip portion is attached to the end of each temple portion. Furthermore, the front portion and the two temple portions can be integrally configured. The assembly of the frame (including the rim portion) and the nose pad has substantially the same structure as ordinary eyeglasses. The material constituting the frame including the nose pad can include the same material as that constituting ordinary eyeglasses, such as metal, alloy, plastic, or a combination thereof. Alternatively, the eyepiece optical system can be in a form of being attached to goggles or in a form of being formed integrally with the goggles, or may be in a form of being attached to a surface member (face member, mask member) having a shape similar to a disaster prevention face that can be mounted on the observer’s head or in a form of being integrally formed with the surface member.

[0080] The eyepiece optical system mounted on the observer has a very simple structure and does not require a battery or the like for driving because it does not have a drive unit, and the eyepiece optical system can be easily reduced in size and weight. Unlike conventional HMDs, the image display apparatus is not mounted on the observer’s head. As described above, the image display apparatus is arranged in an external facility or the like, or is mounted on the observer’s wrist or the like as a wearable device. Examples in which the image display apparatus is arranged in an external facility or the like include:

[0081] (A) An example in which an image display apparatus for passengers is attached to the back surface of a back (backrest) of the seat of a vehicle or aircraft

[0082] (B) An example in which an image display apparatus for audience is attached to the back surface of the back (backrest) of a seat in a theater or the like

[0083] (C) An example in which an image display apparatus for drivers and the like is attached to vehicles, aircraft, automobiles, motorcycles, bicycles, or the like

[0084] (D) An example of being used as an alternative to monitors used in personal computers, mobile phones, smart watches, or the like

[0085] (E) An example of being used as an alternative to a display or touch panel used in an automated teller machine at a financial institution

[0086] (F) An example of being used as an alternative to a display or touch panel used in stores and offices

[0087] (G) An example of enlarging and displaying the screen of a mobile phone or personal computer

[0088] (H) An example of being used as an alternative to a display plate and the like used in museums, amusement parks, or the like

[0089] (I) An example in which an image display apparatus for customers is attached to tables such as of coffee shops and cafes

[0090] In the display apparatus of the present disclosure including various preferable forms and configurations described above, a signal for displaying an image in the image forming apparatus (a signal for forming a virtual image in the eyepiece optical system) can be in a form of being received from the outside (outside the system of the display apparatus). In such a form, information and data associated with an image displayed on the image forming apparatus are recorded, stored, and saved in, for example, a so-called cloud computer or server. As the image display apparatus includes a communication means, such as a telephone line, an optical line, a mobile phone, a smartphone, or by combining an image display apparatus and communication means, it is possible to transfer or exchange various information and data between the cloud computer or server and the image display apparatus. Further, a signal based on various information and data, i.e., a signal for displaying an image in the image forming apparatus can be received. Alternatively, the signal for displaying an image in the image forming apparatus may be in a form of being stored in the image display apparatus. The image displayed on the image forming apparatus includes various information and various data. The image display apparatus, which is a wearable device, can also be in a form of including a camera (imaging apparatus), and the image captured by the camera may be sent to the cloud computer or server via the communication means, and various information and data corresponding to the image captured by the camera may be searched in the cloud computer or server, the various information and data searched may be sent to the image display apparatus via the communication means, and the various information and data searched may be displayed as the image in the image forming apparatus.

[0091] The display apparatus of the present disclosure including the various forms and configurations described above can be used for, for example, display of various information and the like on various sites on the Internet; display of various explanations of operation, manipulation, maintenance, disassembly and the like of observation objects such as various apparatuses and symbols, signs, marks, emblems, designs, and the like; display of various explanations about observation targets such as people and articles and symbols, signs, marks, emblems, designs, and the like; display of moving images or still images; display of subtitles of movies or the like; display of explanations and closed captions related to pictures synchronized with the pictures; various explanations about observation targets in plays, Kabuki, Noh, Kyogen, opera, music concerts, ballet, various plays, amusement grounds (amusement parks), museums, tourist spots, tourist resorts, tourist guides, and the like, and display of explanations or the like for explaining the contents, progress, background, and the like, and display of closed captions. In plays, Kabuki, Noh, Kyogen, opera, concerts, ballet, various plays, amusement grounds (museum parks), museums, tourist spots, tourist resorts, tourist guides, and the like, it is sufficient if characters as images related to observation targets are displayed on the image forming apparatus at an appropriate timing. Specifically, for example, according to the progress status of a movie or the like or according to the progress status of a play or the like, on the basis of a predetermined schedule and time allocation, by an operator’s operation or under the control of a computer or the like, an image control signal is sent to the image forming apparatus, and the image is displayed on the image forming apparatus. Furthermore, display of various explanations about various apparatuses, people, articles, and the like is performed, but the image forming apparatus can perform display of various explanations about observation targets such as the various apparatuses, people, and articles, which are preliminarily formed by taking (capturing) the observation targets such as the various apparatuses, people, and articles with a camera and analyzing the taken (captured) content with the image forming apparatus.

Example 1

[0092] Example 1 relates to the display apparatus of the present disclosure

[0093] As shown in the conceptual diagram of FIG. 1A, a display apparatus 10A of Example 1, if described according to the first aspect of the present disclosure, includes

[0094] an eyepiece optical system 40A, and

[0095] an image display apparatus 20 including an image forming apparatus 21 and a transfer optical system 22 that emits an image incident from the image forming apparatus 21 to the eyepiece optical system 40A. Then, the eyepiece optical system 40A and the image display apparatus 20 are arranged to be spatially separated from each other, and the eyepiece optical system 40A forms an image from the transfer optical system 22 on the retina of an observer 50. The image display apparatus 20 further includes

[0096] a first position detection apparatus 31 that detects the position of the eyepiece optical system 40A,

[0097] a second position detection apparatus 32 that detects the position of a pupil 51 of the observer 50, and

[0098] a transfer optical system controlling apparatus 30, in which

[0099] on the basis of the positional information of the eyepiece optical system 40A detected by the first position detection apparatus 31 and the positional information of the pupil 51 of the observer 50 detected by the second position detection apparatus 32, the transfer optical system controlling apparatus 30 controls the transfer optical system 22 such that the image incident from the image forming apparatus 21 reaches the eyepiece optical system 40A, that is, the image incident from the image forming apparatus 21 is formed on the retina of the observer 50 via the eyepiece optical system 40A.

[0100] Furthermore, a display apparatus 10A of Example 1, if described according to the second aspect of the present disclosure, includes

[0101] an eyepiece optical system 40A, and

[0102] an image display apparatus 20 including an image forming apparatus 21 and a transfer optical system 22 that emits an image incident from the image forming apparatus 21 to the eyepiece optical system 40A. Then, the eyepiece optical system 40A and the image display apparatus 20 are arranged to be spatially separated from each other, and the eyepiece optical system 40A forms an image from the transfer optical system 22 on the retina of an observer 50. The image display apparatus 20 further includes

[0103] a first position detection apparatus 31 that detects the position of the eyepiece optical system 40A,

[0104] a second position detection apparatus 32 that detects the position of a pupil 51 of the observer 50, and

[0105] a transfer optical system controlling apparatus 30, in which

[0106] the second position detection apparatus 32 is arranged at a position where the pupil 51 of the observer 50 can be seen.

[0107] The display apparatus of Example 1 is a retinal projection type display apparatus based on Maxwellian view. Then, in the display apparatus 10A of Example 1, the eyepiece optical system 40A and the image display apparatus 20 are relatively movable. That is, the image display apparatus 20 is arranged at a position away from the observer 50. The eyepiece optical system 40A is mounted on the observer 50 (specifically, on the head of the observer 50). Moreover, the transfer optical system 22 includes a movable mirror. Specifically, when the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) are set with respect to the observer 50, examples of the movable mirror 22 include, for example, a two-dimensionally rotatable mirror or micro electro mechanical systems (MEMS) mirror that moves an image incident from the image forming apparatus 21 in the horizontal direction and the vertical direction. The movable mirror 22 includes a movable mirror that is movable in three axes.

[0108] Here, as described above, it is important that the positional relationship between the second position detection apparatus 32, the eyepiece optical system 40A, and the pupil 51 of the observer 50 has a positional relationship in which the pupil 51 of the observer 50 can be detected from the second position detection apparatus 32. Furthermore, it is also important to give the second position detection apparatus 32 an optical characteristic so that the pupil 51 of the observer 50 can be detected from the second position detection apparatus 32.

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