LIGHT GUIDE, INDICATOR DEVICE AND INDICATOR SYSTEM

Abstract

A light-guiding device is provided that can suppress dimming and invisibility in the center of a display area.The light guiding device according to the present technology comprises a light guiding system that directs light emitted from a light source device to the eyeballs, wherein the light guiding system has an optical element comprising a first and a second diffraction element which are opposite each other, light emitted from the light source device and projected onto the first diffraction element at a predetermined angle of incidence is reflected and diffracted at the first diffraction element, the light reflected and diffracted at the first diffraction element is reflected and diffracted at the second diffraction element, the light reflected and diffracted at the second diffraction element and transmitted through the first diffraction element is directed to the eyeballs, the second diffraction element has a lens function and the first and the second diffraction element vary with respect to the difference in refractive index and thickness.

Description

[Technical field]

[0001] The present technology relates to a light guide device, a display device and a display system. [State of the art]

[0002] In recent years, techniques for superimposing images on an external scene have received attention. Such a technique is also called augmented reality (AR) technology. A head-mounted display is an example of a product that uses such a technique. A head-mounted display is used while attached to a user's head. In an image display method that uses a head-mounted display, for example, light from the head-mounted display, in addition to external light, reaches a user's eyes, so that the user perceives that an image of light from the display is superimposed on an external image.

[0003] For example, PTL 1 proposes a light guide device including a virtual optical image system that improves contrast, light utilization efficiency, and see-through efficiency. [Citation list][Patent literature]

[0004] [PTL 1] JP 2005-148655 A [Summary][Technical Problem]

[0005] However, in the technique proposed in PTL 1, the center of a display area may become dark or invisible.

[0006] Thus, the present technique was developed under such circumstances. A primary objective of the present technique is to provide a light guide device that can suppress dimming and invisibility in the center of a display area. [Solution to the problem]

[0007] The present technique provides a light guiding device comprising a light guiding system that guides light emitted from a light source device to eyeballs, wherein the light guide system has an optical element comprising first and second diffraction elements that are opposite to each other, light emitted by the light source device and projected onto the first diffraction element at a predetermined angle of incidence is reflected and diffracted at the first diffraction element, the light transmitted through the first diffraction element is reflected and diffracted at the second diffraction element, and the light transmitted through the first diffraction element via the second diffraction element is guided to the eyeballs, the second diffraction element has a lens function, and the first and second diffraction elements vary in refractive index difference and / or thickness.

[0008] The first and second diffractive elements may vary with respect to the product of a refractive index difference and a thickness.

[0009] A first product as the product of the refractive index difference and the thickness of the first diffractive element may be larger than a second product as the product of the refractive index difference and the thickness of the second diffractive element.

[0010] The first and second diffraction elements may have different refractive index differences.

[0011] The first diffraction element may have a larger refractive index difference than the second diffraction element.

[0012] The first and second diffraction elements may have different thicknesses.

[0013] The second diffraction element may have a greater thickness than the first diffraction element.

[0014] The first and second diffraction elements may vary in terms of refractive index difference and thickness.

[0015] The first diffractive element may have a larger refractive index difference than the second diffractive element, and the second diffractive element may have a greater thickness than the first diffractive element.

[0016] The first and second diffraction elements may be identical in thickness and the first diffraction element may have a larger refractive index difference than the second diffraction element.

[0017] The first and second diffraction elements may be identical with respect to the refractive index difference and the second diffraction element may have a greater thickness than the first diffraction element.

[0018] When the first and second diffraction elements have thicknesses in µm, the first product may be 0.2 or more and the first diffraction element may have a thickness of 1 µm to 100 µm.

[0019] When the first and second diffraction elements have thicknesses in µm, the first product may be 0.4 or more and the first diffraction element may have a thickness of 2 µm to 30 µm.

[0020] If the first and second diffraction elements have thicknesses in µm, the second product may be 0.1 or less and the second diffraction element may have a thickness of 1 µm to 100 µm.

[0021] When the first and second diffraction elements have thicknesses in µm, the second product may be 0.02 or less and the second diffraction element may have a thickness of 10 µm to 40 µm.

[0022] The optical axis of the second diffraction element and the vertical line of the first diffraction element may be parallel to each other.

[0023] The optical axis of the second diffraction element and the vertical line of the first diffraction element cannot be parallel.

[0024] Light projected onto the first diffraction element at the predetermined angle of incidence may be light emitted from the light source device and transmitted through the second diffraction element.

[0025] The light guide system may further comprise a light guide plate disposed at least partially between the first and second diffraction elements and guiding light from the light source device, and light projected onto the first diffraction element at the predetermined angle of incidence may be light emitted from the light source device and guided through the light guide plate.

[0026] The first diffraction element can reflect and diffract light projected onto the first diffraction element at the predetermined angle of incidence in a regular reflection direction.

[0027] The first diffraction element can reflect and diffract light projected onto the first diffraction element at the predetermined angle of incidence in an incident direction.

[0028] The first diffraction element can reflect and diffract light projected onto the first diffraction element at the predetermined angle of incidence in a direction different from both the regular reflection direction and the incidence direction.

[0029] At least one of the first and second diffraction elements may have a curved element surface.

[0030] At least one of the first and second diffraction elements may be a hologram optical element.

[0031] The optical element may be attached to the eyeball or embedded in it. The present technique provides a display device comprising: the light guide device and the light source device.

[0032] In the display device, the light source device and the light guide device may be provided integrally.

[0033] The present technique provides a display system comprising: the display device and a controller that controls the display device. [Brief description of the drawings] [ Fig. 1] Fig. 1 is an explanatory drawing illustrating that display light is projected onto an optical element and the display light is allowed to reach a retina through the optical element. [ Fig. 2] Fig. 2 is an explanatory drawing of a path before display light incident on the optical element is emitted from the optical element. [ Fig. 3] Fig. Figure 3 shows the coordinates of the diffraction efficiency of display light reaching a retina. [ Fig. 4] Fig. 4 is an explanatory drawing of a path before display light incident on the optical element is emitted from the optical element. [ Fig. 5] Fig. Figure 5 is a graph showing the relationship between an incident angle and a diffraction efficiency when Δn = 0.02 is obtained in a HOE. [ Fig. 6] Fig. Figure 6 is a graph showing the relationship between an incident angle and a diffraction efficiency when Δn = 0.04 is obtained in the HOE. [ Fig. 7] Fig. Figure 7 is a graph showing the relationship between an incident angle and a diffraction efficiency when Δn = 0.1 is obtained in the HOE. [ Fig. 8] Fig. Figure 8 is a graph showing the relationship between an incident angle and a diffraction efficiency when Δn = 0.2 is obtained in the HOE. [ Fig. 9] Fig. Figure 9 is a graph showing the relationship between an incident angle and a diffraction efficiency of two cases where a corresponding incident angle range in the HOE is identical. [ Fig. 10] Fig. 10 is a graph showing the relationship between an incident angle and a diffraction efficiency for a variety of combinations of Δn and T when Δn × T = 1.0 is obtained in the HOE. [ Fig. 11] Fig. Figure 11 is a graph showing the relationship between an incident angle and a diffraction efficiency for a variety of combinations of Δn and T when Δn × T = 0.8 is obtained in the HOE. [ Fig. 12] Fig. 12 is a graph showing the relationship between an incident angle and a diffraction efficiency for a variety of combinations of Δn and T when Δn × T = 0.6 is obtained in the HOE. [ Fig. 13] Fig. Figure 13 is a graph showing the relationship between an incident angle and a diffraction efficiency for a variety of combinations of Δn and T when Δn × T = 0.4 is obtained in the HOE. [ Fig. 14] Fig. 14 is a graph showing the relationship between an incident angle and a diffraction efficiency for a variety of combinations of Δn and T when Δn × T = 0.2 is obtained in the HOE. [ Fig. 15] Fig. 15 is a graph showing the relationship between an incident angle and a diffraction efficiency for a variety of Δn when T = 10 µm is obtained in the HOE. [ Fig. 16] Fig. 16 is an explanatory drawing of the functional example 1 of the HOE. [ Fig. 17] Fig. Figure 17 is an explanatory drawing of the HOE functional example 2. [ Fig. 18] Fig. 18 is an explanatory drawing of the functional example 3 of the HOE. [ Fig. 19] Fig. Figure 19 is an explanatory drawing of the HOE functional example 4. [ Fig. 20] Fig. Figure 20 is an explanatory drawing of the HOE functional example 5. [ Fig. 21] Fig. 21 illustrates a configuration example of a light guide device according to a first embodiment of the present technique. [ Fig. 22] Fig. 22 illustrates a configuration example of a light guide device according to a second embodiment of the present technique. [ Fig. 23] Fig. 23 illustrates a configuration example of a light guide device according to a third embodiment of the present technique. [ Fig. 24] Fig. 24 illustrates a configuration example of a light guide device according to a fourth embodiment of the present technique. [ Fig. 25] Fig. 25 illustrates a configuration example of a light guide device according to a fifth embodiment of the present technique. [ Fig. 26] Fig. 26 illustrates a configuration example of a light guide device according to a sixth embodiment of the present technique. [ Fig. 27] Fig. 27 illustrates a configuration example of a light guide device according to a seventh embodiment of the present technique. [ Fig. 28] Fig. 28 illustrates a configuration example of a light guide device according to an eighth embodiment of the present technique. [ Fig. 29] Fig. 29 illustrates a configuration example of a light guide device according to a ninth embodiment of the present technique. [ Fig. 30] Fig. 30 illustrates a configuration example of a light guide device according to a tenth embodiment of the present technique. [ Fig. 31] Fig. 31 illustrates a configuration example of a light guide device according to an eleventh embodiment of the present technique. [ Fig. 32] Fig. 32 is a functional block diagram illustrating a display system according to a thirteenth embodiment of the present technique. [ Fig. 33] Fig. 33A to Fig. 33F show diffraction efficiency distributions on an eyeball for different combinations of refractive index difference and film thickness when the product of the refractive index difference and film thickness of the deflection HOE is constant. [ Fig. 34] Fig. 34A to Fig. 34F show diffraction efficiency distributions on an eyeball for different combinations of refractive index difference and film thickness when the product of the refractive index difference and film thickness of the deflection HOE is constant. [Description of embodiments]

[0034] Preferred embodiments for implementing the present technique will be described below. The embodiments described below show an example of a representative embodiment of the present technique, and the scope of the present technique should not be narrowly interpreted based on the embodiments. In the drawings, unless otherwise specified, "top" means the upper direction or the upper side in the drawing, "bottom" means the lower direction or the lower side in the drawing, "left" means the left direction or the left side in the drawing, and "right" means the right direction or the right side in the drawing. The same reference numerals are applied to the same or equivalent elements or elements in the drawings, and repeated descriptions are omitted unless exceptional circumstances arise.

[0035] The description is given in the following order. 1. Overview of the present technology 2. Detail of the present technology 3. Optical fiber device of the first embodiment 4. Optical fiber device of the second embodiment 5. Optical fiber device of the third embodiment 6. Optical fiber device of the fourth embodiment 7. Optical fiber device of the fifth embodiment 8. Optical fiber device of the sixth embodiment 9. Optical fiber device of the seventh embodiment 10. Optical fiber device of the eighth embodiment 11. Optical fiber device of the ninth embodiment 12. Optical fiber device of the tenth embodiment 13. Optical fiber device of the eleventh embodiment 14. Display device of the twelfth embodiment 15. Display system of the thirteenth embodiment <1. Overview of the present technology

[0036] First, the overview of the present technology is described. The present technology relates to a light guide device, a display device, and a display system.

[0037] For example, if an AR (augmented reality) display device has optical elements including first and second diffraction elements that oppose each other, light reflected and diffracted by the first diffraction element enters the second diffraction element. The light reflected and diffracted by the second diffraction element re-enters the first diffraction element. The incident light passes through the first diffraction element and enters the eyeballs.

[0038] However, if the light diffracted by the second diffraction element forms an angle close to the diffraction angle of the first diffraction element, the light incident on the first diffraction element is diffracted again. This reduces the light entering the eyeballs and can thus cause a reduction in light or invisibility in the center of a display field of view. A detailed description follows.

[0039] For example, a display device projects display light onto an optical contact lens element from an image projection device and forms an image of the display light on the retina through the optical element. The optical contact lens element includes a reflection volume hologram of a deflection HOE (Holographic Optical Element, as referred to below) and a lens HOE (Holographic Optical Element, as referred to below). The HOE, with a structure that diffracts incident light at any angle, exhibits a diffraction effect for a target wavelength only at a specific angle.

[0040] The structure is described with reference to Fig. 1 described. Fig. 1 is an explanatory drawing illustrating that five display light beams (LA to LE) are projected onto a contact lens optical element 1-100, and the optical element 1-100 causes the display light beams to reach a retina M1 through the optical element 1-100. Fig. Fig. 1B is an enlarged view of a part designated by reference character A-1 in Fig. 1A. The five indicator light beams (LA to LE) converge to a point (focal point S-100) around a pupil M3. Reference symbol M2 denotes an iris. As shown in Fig. As illustrated in Fig. 1B, the optical element 1-100 is configured with a deflection HOE 10-100 serving as a first diffraction element and with a lens HOE 20-100 (a diffraction element having a lens function) serving as a second diffraction element.

[0041] As indicated by reference numerals F1 to F5 of Fig. 1B, when the deflection HOE 10-100 has an angle of incidence and a diffraction angle of 0°, the angle of incidence of the lens HOE 20-100 and the optical axis of a condenser lens are both set to 0°.

[0042] The structure is described with reference to Fig. 2 described. Fig. Figure 2 is an explanatory drawing of a path before a display light beam projected onto the optical element is emitted from the optical element. Fig. The optical element illustrated in Fig. 2 comprises a protective layer 700, a lens HOE 20, a deflection HOE 10 and a protective layer 600 in this order from the incident side of the incident light L0 (sequentially from the top of Fig. 2).

[0043] Fig. Figure 2 illustrates only one optical axis component of the diffracted light of the lens HOE 20. The incident light L0 passes through the lens HOE 20, one component (light beam L1) enters the deflection HOE 10 and is diffracted, and one component (light beam L11) passes through the deflection HOE 10. In this structure, undiffracted light passes through the HOE unless the diffraction efficiency is 100%.

[0044] In this case, as in Fig. 2, the light beam (light beam L1) is diffracted by the deflection HOE 10, a light beam (light beam L2) is diffracted by the lens HOE 20, and only a transmitted light beam L31 of the light beam L2 which has entered the deflection HOE 10 again serves as an image display light beam.

[0045] In Fig. 1, however, a light beam enters the lens HOE 20-100, and the optical axis, which has been collimated, reflected, and diffracted as a lens, and the angle of incidence of the deflection HOE 10-100 for re-entry coincide. Thus, a light beam component close to the optical axis is diffracted by the deflection HOE (for example, a light beam L3 in Fig. 2). A collimating light beam component away from the optical axis deviates from an angle at which the deflection HOE has a diffraction effect, so that the light beam passes through the deflection HOE (for example, a light beam L31 in Fig. 2).

[0046] Now follows a description with reference to Fig. 3. Fig. Figure 3 shows the coordinates of the diffraction efficiency of display light reaching a retina on an optical contact lens element as a technical example. Reference symbol P2 in Fig. 3 indicates a region of high diffraction efficiency, and reference symbol P1 indicates a region that should not be diffracted. In this case, the optical axis of a lens HOE corresponds to a fovea centralis on the retina.

[0047] In reality, 100% diffraction efficiency cannot be achieved, allowing some light near the optical axis of the lens HOE to pass through. Only a few display light rays near the optical axis reach the retina, resulting in the darkening of the central portion of a display area.

[0048] Since the display of the fovea centralis, which is the most important in the display area, is obscured, the present technique was developed to avoid this problem.

[0049] Now follows a description with reference to Fig. 4. Fig. 4 is an explanatory drawing of a path before a display light beam projected onto the optical element is emitted from the optical element.

[0050] A light beam reaching the retina as a display light beam (image display light beam) is only one component that has passed through the deflection HOE 10 among light beams that have re-entered the deflection HOE 10 (light beam L31). A schematic path before the image display light beam reaches the retina includes, in this order, (1) projection of the incident light L0, (2) diffraction by the deflection HOE 10 (light beam L1), (3) diffraction by the lens HOE 20 (light beam L2), (4) passing through the deflection HOE (light beam L31), and (5) reaching the retina. <2. Detail of the present technique

[0051] A detailed description of the present technique follows. (Inventor's idea)

[0052] The inventor found that dimming and invisibility in the center of a display area can be suppressed by adjusting a refractive index difference Δn and / or a film thickness T (thickness) of both a deflection HOE serving as a first diffraction element and a lens HOE serving as a second diffraction element, the diffraction elements being provided for an optical element formed as a contact lens or embedded in the eyeball.

[0053] In particular, the inventor focused on the fact that the diffraction characteristics of the HOE, i.e., the diffraction efficiency and a corresponding angle of incidence range, can be changed by changing the refractive index difference Δn and / or a film thickness T (thickness) of the HOE. In this case, "corresponding angle of incidence range" means the range of the angle of incidence of light onto the HOE when the diffraction efficiency of the HOE exceeds a predetermined value (for example, a predetermined value of 1 to 100%). "Corresponding angle of incidence range" may be referred to as "effective angle of incidence range." (Basic configuration of a fiber optic device)

[0054] A light guide device according to the present technique includes a light guide system that guides light emitted from a light source device to eyeballs. The light guide system has an optical element including first and second diffraction elements (e.g., a deflection HOE and a lens HOE) that are opposite to each other. Light emitted from a light source device and projected onto the first diffraction element (e.g., the deflection HOE) at a predetermined angle of incidence is reflected and diffracted by the first diffraction element; the light reflected and diffracted by the first diffraction element is reflected and diffracted by the second diffraction element (e.g., the lens HOE); and the light reflected and diffracted by the second diffraction element and transmitted through the first diffraction element is guided to the eyeballs. (Diffraction properties of the HOE)

[0055] In the present technique, diffraction characteristics are described considering a concept in which a product Δn × T of a refractive index difference Δn and a film thickness T serves as an index. In this case, the diffractive element can exhibit a diffraction function by alternately placing two or more types of regions with different refractive indices. A difference in refractive index is called a refractive index difference.

[0056] Fig. Figure 5 is a graph showing the relationship between an incident angle and a diffraction efficiency for several thicknesses T(hth) when Δn(dn) = 0.02 is obtained in the HOE. Fig. Figure 6 is a graph showing the relationship between an incident angle and a diffraction efficiency for several thicknesses T(hth) when Δn(dn) = 0.04 is obtained in the HOE. Fig. Figure 7 is a graph showing the relationship between an incident angle and a diffraction efficiency for several thicknesses T(hth) when Δn(dn) = 0.1 is obtained in the HOE. Fig. Figure 8 is a graph showing the relationship between an incident angle and a diffraction efficiency for several thicknesses T(hth) when Δn(dn) = 0.2 is obtained in the HOE. Fig. Figure 9 is a graph showing the relationship between an incident angle and a diffraction efficiency of two cases where a corresponding incident angle range in the HOE is identical. In Fig. 5 to Fig. 9, the wavelength of light incident on the HOE is, for example, 540 nm.

[0057] As from Fig. 5 to Fig. As can be seen from Figure 8, when Δn is kept constant, the corresponding angle of incidence narrows and the diffraction efficiency increases as T increases, whereas the corresponding angle of incidence widens and the diffraction efficiency decreases as T decreases.

[0058] A comparison between Fig. 5 to Fig. 8 proves that when a film thickness is kept constant, the corresponding incident angle range tends to expand as Δn increases.

[0059] As from Fig. As can be seen from Figure 9, when the corresponding angle of incidence range is identical, fewer wavelengths in the corresponding angle of incidence range are disturbed and the display is less affected as Δn × T decreases.

[0060] Fig. Figure 10 is a graph showing the relationship between an incident angle and a diffraction efficiency for several combinations of Δn(dn) and T(hth) when Δn × T = 1.0 is obtained in the HOE. Fig. Figure 11 is a graph showing the relationship between an incident angle and a diffraction efficiency for several combinations of Δn(dn) and T(hth) when Δn × T = 0.8 is obtained in the HOE. Fig. Figure 12 is a graph showing the relationship between an incident angle and a diffraction efficiency for several combinations of Δn(dn) and T(hth) when Δn × T = 0.6 is obtained in the HOE. Fig. Figure 13 is a graph showing the relationship between an incident angle and a diffraction efficiency for several combinations of Δn(dn) and T(hth) when Δn × T = 0.4 is obtained in the HOE. Fig. Figure 14 is a graph showing the relationship between an incident angle and a diffraction efficiency for several combinations of Δn(dn) and T(hth) when Δn × T = 0.2 is obtained in the HOE. Fig. Figure 15 is a graph showing the relationship between an incident angle and a diffraction efficiency for several Δn(dn) when T = 10 µm is obtained in the HOE. In Fig. 10 to Fig. 15, the wavelength of light incident on the HOE is, for example, 540 nm.

[0061] As from Fig. 10 to Fig. As can be seen from Figure 14, a corresponding incident angle range can be obtained more stably as Δn × T increases. However, when Δn × T exceeds 0.8 μm, the peak of the diffraction efficiency (maximum diffraction efficiency) is saturated, which makes it difficult to obtain the enhancement effect. The smaller the film thickness, the wider the corresponding incident angle range. For film thicknesses on the order of μm, the manufacturing tolerance is large, and variations in properties increase when the film thickness is 5 μm or less.

[0062] As from Fig. 10 to Fig. As can be seen from Figure 14, the diffraction efficiency of the HOE is proportional to Δn × T.

[0063] As from Fig. As can be seen from Figure 15, when T is kept constant, the corresponding angle of incidence range expands and the diffraction efficiency improves as Δn increases.

[0064] As can be seen from the study, the diffraction characteristics of the HOE can be controlled by adjusting Δn and / or T. The inventor successfully suppresses dimming and invisibility in the center of a display area by providing diffraction characteristics suitable for the deflection HOE and the lens HOE according to this method.

[0065] In particular, the deflection HOE and the lens HOE preferably vary with respect to the refractive index difference Δn and / or the film thickness T (thickness). The deflection HOE and the lens HOE preferably vary with respect to the product Δn × T of the refractive index difference Δn and the film thickness T (thickness). In other words, for a first product Δn1 × T1 of a refractive index difference Δn1 and a film thickness T1 of the deflection HOE and a second product Δn2 × T2 of a refractive index difference Δn2 and a film thickness T2 of the lens HOE, Δn1 × T1 > Δn2 × T2 or Δn1 × T1 < Δn2 × T2 is preferably set.

[0066] Since eyeballs rotate in the configuration for projection from the image projection device to the optical contact lens element, the deflection HOE preferably has a wide corresponding angle of incidence range and high diffraction efficiency. In other words, when Δn1 × T1 is kept constant, the deflection HOE preferably has a large value of Δn1 and a small value of T1. This is because light incident on the deflection HOE varies in angle of incidence, and low diffraction efficiency increases zero-order light, which can cause an adverse effect.

[0067] In the following example, light projected by the image projection device and caused to enter the deflection HOE in a direction of, for example, 60° from the normal line of the optical contact lens element is reflected and diffracted at, for example, 60° in a regular reflection direction. The optical axis of the lens HOE and the perpendicular line of the deflection HOE are parallel to each other.

[0068] Fig. 33A to Fig. 33F show diffraction efficiency distributions on an eyeball for different combinations of refractive index difference and film thickness, when the product of the refractive index difference and film thickness of the deflection HOE is constant (equal). In Fig. 33A to Fig. 33F, the horizontal axis indicates a position in the Y-axis direction on the light guide device, and the vertical axis indicates a position in the X-axis direction on the light guide device. In Fig. 33A to Fig. 33F, a darker area has a higher diffraction efficiency, whereas a brighter area has a lower diffraction efficiency. In the examples of Fig. 33A to Fig. 33F, the film thickness of the lens HOE is set to 3 µm and the refractive index difference thereof is set to 0.2.

[0069] Fig. Figure 33A shows the diffraction efficiency distribution of a combination of film thickness hth = 3 µm and dn = 0.2. Fig. Figure 33B shows the diffraction efficiency distribution of a combination of film thickness hth = 4 µm and dn = 0.15. Fig. Figure 33C shows the diffraction efficiency distribution of a combination of film thickness hth = 6 µm and dn = 0.1. Fig. Figure 33D shows the diffraction efficiency distribution of a combination of film thickness hth = 8 µm and dn = 0.075. Fig. Figure 33E shows the diffraction efficiency distribution of a combination of film thickness hth = 10 µm and dn = 0.06. Fig. Figure 33F shows the diffraction efficiency distribution of a combination of film thickness hth = 15 µm and dn = 0.04.

[0070] As from Fig. 33A to Fig. As can be seen from Figure 33F, when the first product Δn1 × T1 of the refractive index difference Δn1 and the film thickness T1 is kept constant, the deflection HOE has a larger fovea centralis, which has high diffraction efficiency on the retina, as Δn1 decreases (as T1 increases). Thus, the deflection HOE preferably has a relatively small Δn1 (relatively large T1) when Δn1 × T1 is kept constant.

[0071] The lens HOE preferably has a narrow corresponding angle of incidence range. This is because less diffraction is preferred when light passes through the lens HOE. The lens HOE does not necessarily need to have high diffraction efficiency, as low diffraction efficiency only reduces light utilization efficiency and does not affect the display. In other words, the lens HOE preferably has a large T-value.

[0072] In the following example, light projected by the image projection device and caused to enter the deflection HOE in a direction of, for example, 60° from the normal line of the optical contact lens element is reflected and diffracted at, for example, 80° in a regular reflection direction. The optical axis of the lens HOE and the perpendicular line of the deflection HOE are parallel to each other.

[0073] Light from the image projection device first passes through the lens HOE and then enters the deflection HOE. If incident light is first diffracted by the lens HOE, a transmitted light beam may be lost. Thus, the diffraction efficiency obtained first by the lens HOE is preferably minimized, and a diffraction characteristic distribution in a fovea centralis region in the Fig. 34A to Fig. 34F is preferably minimized. Fig. 34A to Fig. 34F show diffraction efficiency distributions on an eyeball for various combinations of refractive index difference and film thickness, when the product of the refractive index difference and film thickness of the deflection HOE is constant (equal) for the light first incident on the lens HOE. In Fig. 34A to Fig. 34F, the horizontal axis indicates a position in the Y-axis direction on the light guide device, and the vertical axis indicates a position in the X-axis direction on the light guide device. In Fig. 34A to Fig. 34F, a darker area has a higher diffraction efficiency, whereas a brighter area has a lower diffraction efficiency. In the examples of Fig. 34A to Fig. 34F, the film thickness of the lens HOE is set to 15 µm and the refractive index difference thereof is set to 0.04.

[0074] Fig. Figure 34A shows the diffraction efficiency distribution of a combination of film thickness hth = 3 µm and dn = 0.2. Fig. Figure 34B shows the diffraction efficiency distribution of a combination of film thickness hth = 4 µm and dn = 0.15. Fig. Figure 34C shows the diffraction efficiency distribution of a combination of film thickness hth = 6 µm and dn = 0.1. Fig. Figure 34D shows the diffraction efficiency distribution of a combination of film thickness hth = 8 µm and dn = 0.075. Fig. Figure 34E shows the diffraction efficiency distribution of a combination of film thickness hth = 10 µm and dn = 0.06. Fig. Figure 34F shows the diffraction efficiency distribution of a combination of film thickness hth = 15 µm and dn = 0.04.

[0075] As can be seen from the Fig. 34A to Fig. As can be seen from Fig. 34F, when the second product Δn2 × T2 of the refractive index difference Δn2 and the film thickness T2 is kept constant, the lens HOE has a smaller area of ​​high diffraction efficiency in a fovea centralis area on the retina as Δn2 decreases (as T2 increases), the area created on the retina by the lens HOE by light first entering the lens HOE. Thus, the lens HOE preferably has a relatively small Δn2 (relatively large T2) when Δn2 × T2 is kept constant.

[0076] The first product Δn1 × T1 of the refractive index difference Δn1 and the film thickness T1 of the deflection HOE is preferably larger than the second product Δn2 × T2 of the refractive index difference Δn2 and the film thickness T2 of the lens HOE (Δn1 × T1 > Δn2 × T2). Thus, the corresponding incident angle range of the deflection HOE can be relatively large, the corresponding incident angle range of the lens HOE can be relatively small, and the diffraction efficiency of the deflection HOE can be relatively high.

[0077] The deflection HOE and the lens HOE can have different refractive index differences. In this case, the deflection HOE preferably has a larger refractive index difference than the lens HOE (Δn 1 > Δn 2 ). Thus, the diffraction efficiency of the deflection HOE can be relatively high.

[0078] The deflection HOE and the lens HOE can have different film thicknesses T (thicknesses). In this case, the lens HOE preferably has a greater thickness than the deflection HOE (T2 > T1). Thus, the corresponding angle of incidence range of the lens HOE can be relatively small.

[0079] The deflection HOE and the lens HOE can have different refractive index differences and thicknesses. In this case, the deflection HOE preferably has a larger refractive index difference than the lens HOE (Δn1 > Δn2), and the lens HOE preferably has a larger thickness than the deflection HOE (T2 > T1). Thus, the diffraction efficiency of the deflection HOE can be relatively high, and the corresponding angle of incidence range of the lens HOE can be relatively small.

[0080] The deflection HOE and the lens HOE can have the same thickness (T1 = T2), and the deflection HOE can have a larger refractive index difference than the lens HOE (Δn1 > Δn2) (see Fig. 15). Thus, the diffraction efficiency and the corresponding angle of incidence range of the deflection HOE can be relatively high.

[0081] The deflection HOE and the lens HOE can have the same refractive index difference (Δn1 = Δn2). In this case, although the deflection HOE and the lens HOE only need to have different film thicknesses, they preferably have a greater thickness than the deflection HOE. Thus, the corresponding angle of incidence of the deflection HOE can be relatively large, and the corresponding angle of incidence of the lens HOE can be relatively small.

[0082] The first product Δn1 × T1 is preferably 0.2 or more, and the deflection HOE preferably has a thickness of 1 µm to 100 µm (see Fig. 10 to Fig. 14). Thus, the corresponding incidence angle range of the deflection HOE can be extended while suppressing variations in the properties.

[0083] The first product Δn1 × T1 is preferably 0.4 or more, and the deflection HOE preferably has a thickness of 2 µm to 30 µm (see Fig. 10 to Fig. 14). Thus, the corresponding incident angle range and the diffraction efficiency of the deflection HOE can be increased while suppressing variations in the properties.

[0084] Δn2 is preferably 0.1 or less, and the lens HOE preferably has a thickness of 1 μm to 100 μm. Thus, the corresponding incident angle range of the lens HOE can be narrowed while suppressing variations in properties.

[0085] Δn2 is more preferably 0.05 or less (preferably 0.02 or less), and the lens HOE more preferably has a thickness of 10 μm to 40 μm. Thus, the corresponding incident angle range of the lens HOE can be narrowed while suppressing variations in properties.

[0086] When the deflection HOE diffracts incident light in the regular reflection direction, the following formula (1) is preferably set for an incident angle θi of light on the deflection HOE, a lens aperture diameter D, and a lens focal length f. θi≥atan(D / (2f))

[0087] When the deflection HOE diffracts incident light in the regular reflection direction, the following formula (2) is preferably set for an incident angle θi of light to the deflection HOE, a lens aperture diameter D, a lens focal length f, and a diffraction angle characteristic range width ΔθwiL of the lens HOE. θi≥atan(D / (2f))+ΔθwiL

[0088] When the deflection HOE diffracts incident light in the regular reflection direction, the following formula (3) is preferably set for an incident angle θi of light to the deflection HOE, an aperture diameter D, a lens focal length f, and a diffraction angle characteristic range width ΔθwiH of the deflection HOE. θi≥atan(D / (2f))+ΔθwiH

[0089] When the deflection HOE diffracts incident light in the incident direction, the following formula (4) is preferably set for an incident angle θi of light to the deflection HOE, a deflection diffraction angle θHi of the deflection HOE, a lens focal length f, and a diffraction angle characteristic range width ΔθwiL of the lens HOE. θi≥θHi≥atan(D / (2f))

[0090] When the deflection HOE diffracts incident light in the incident direction, the following formula (5) is more preferably set for an incident angle θi of light to the deflection HOE, a deflection diffraction angle θHi, a lens focal length f, a diffraction angle characteristic range width ΔθwiL of the lens HOE, and a diffraction angle characteristic range width ΔθwiH of the deflection HOE. θi≥θHi+ΔθwiH≥atan(D / (2f))+ΔθwiL (Functional example 1 of the HOE)

[0091] Fig. Figure 16 is an explanatory drawing of the HOE functional example 1. In this case, as shown in the upper right drawing of Fig. 16, a projected light beam transmitted through the lens HOE is diffracted at the deflection HOE in the regular reflection direction. As shown in the upper left drawing of Fig. 16, a light beam reflected and diffracted at the deflection HOE in the regular reflection direction is incident as a desired incident light beam on the lens HOE with a diffraction efficiency of 100%, and the light beam is reflected and diffracted to converge as a desired diffracted light beam at the lens HOE. As shown in the lower right drawing of Fig. As illustrated in Fig. 16, a light beam projected onto the lens HOE having a diffraction efficiency of 1 is reflected from the side opposite to the deflection HOE and diffracted to be scattered onto the side opposite to a light convergence point of a diffracted light beam at the lens HOE. (Functional example 2 of the HOE)

[0092] Fig. 17 is an explanatory drawing of the HOE functional example 2. As shown in the upper right drawing of Fig. 17, a projected light beam transmitted through the lens HOE is reflected and diffracted at the deflection HOE in the regular reflection direction. As shown in the upper left drawing of Fig. As illustrated in Figure 17, a part of a projected light beam (incident light) is transmitted to the lens HOE at an incident angle θ1 (an incident angle within the diffraction angle characteristic range width of the deflection HOE and close to the diffraction angle characteristic range width of the lens HOE) through the lens HOE, is reflected and diffracted at the deflection HOE in the regular reflection direction, and is caused to re-enter the lens HOE, and the other part is reflected and diffracted outward as diffracted light at the lens HOE. The light beam caused to re-enter the lens HOE is reflected and diffracted as diffracted light at the lens HOE to converge. In other words, in the example of the upper left drawing of Fig. 17 incident light is partially lost. In the example shown in the lower right drawing of Fig. 17, a projected light beam (incident light) is transmitted to the lens HOE at an incident angle θ2 (an incident angle within the diffraction angle characteristic range width of the deflection HOE and significantly larger than θ1 outside the diffraction angle characteristic range width of the lens HOE), is largely transmitted through the lens HOE, is reflected and diffracted at the deflection HOE in the regular reflection direction, and is caused to re-enter the lens HOE. The light beam caused to re-enter the lens HOE is reflected and diffracted as diffracted light at the lens HOE to converge. In other words, in the example of the lower right drawing of Fig. 17, incident light is hardly lost. As described above, the angle of incidence of a projected light beam (incident light) on the deflection HOE is set to a predetermined value or greater (for example, θi in formulas (1) to (5)), thereby suppressing loss of incident light. (Functional example 3 of the HOE)

[0093] Fig. Figure 18 is an explanatory drawing of the HOE functional example 4. In this case, as shown in the upper right drawing of Fig. 18, a projected light beam transmitted through the lens HOE is reflected and diffracted at the deflection HOE in the direction of incidence. As shown in the upper left drawing of Fig. 18, a light beam reflected and diffracted at the deflection HOE in the incident direction is incident as a desired incident light beam on the lens HOE with a diffraction efficiency of 100%, and the light beam is reflected and diffracted to converge as a desired diffracted light beam at the lens HOE. As shown in the lower right drawing of Fig. As illustrated in Fig. 18, a light beam projected onto the lens HOE having a diffraction efficiency of 1 is reflected from the side opposite to the deflection HOE and diffracted to be scattered onto the side opposite to a light convergence point of a diffracted light beam at the lens HOE. (Functional example 4 of the HOE)

[0094] Fig. 19 is an explanatory drawing of the HOE functional example 2. As shown in the upper right drawing of Fig. 19, a projected light beam transmitted through the lens HOE is reflected and diffracted at the deflection HOE in the direction of incidence. As shown in the upper left drawing of Fig. As illustrated in Figure 19, a part of a projected light beam (incident light) is transmitted to the lens HOE at an incident angle θ1 (an incident angle within the diffraction angle characteristic range width of the deflection HOE and close to the diffraction angle characteristic range width of the lens HOE) through the lens HOE, is reflected and diffracted at the deflection HOE in the incident direction, and is caused to re-enter the lens HOE, and the other part is reflected and diffracted outward as diffracted light at the lens HOE. The light beam caused to re-enter the lens HOE is reflected and diffracted as diffracted light at the lens HOE to converge. In other words, in the example of the upper left drawing of Fig. 19 incident light is partially lost. In the example shown in the lower right drawing of Fig. 19, a projected light beam (incident light) is transmitted to the lens HOE at an incident angle θ2 (an incident angle within the diffraction angle characteristic range width of the deflection HOE and significantly larger than θ1 outside the diffraction angle characteristic range width of the lens HOE), is largely transmitted through the lens HOE, is reflected and diffracted at the deflection HOE in the incident direction, and is caused to re-enter the lens HOE. The light beam caused to re-enter the lens HOE is reflected as diffracted light at the lens HOE and diffracted to converge. In other words, in the example of the lower right drawing of Fig. 19, incident light is hardly lost. As described above, the angle of incidence of a projected light beam (incident light) on the deflection HOE is set to a predetermined value or larger (for example, θi in formulas (1) to (5)), thereby suppressing loss of incident light. (Functional example 5 of the HOE)

[0095] Fig. 20 is an explanatory drawing of the HOE functional example 5. As shown in the right drawing of Fig. 20, a projected light beam transmitted through the lens HOE is reflected and diffracted at the deflection HOE in the direction of incidence. As shown in the left drawing of Fig. 20, a part of a projected light beam (incident light) is transmitted to the lens HOE at an incident angle θ3 (an incident angle within the diffraction angle characteristic range width of the deflection HOE and smaller than θ1 within the diffraction angle characteristic range width of the lens HOE) through the lens HOE, is reflected and diffracted at the deflection HOE in the incident direction, and is caused to re-enter the lens HOE, and the other part (equivalently) is reflected and diffracted outward as diffracted light at the lens HOE. The light beam caused to re-enter the lens HOE is reflected and diffracted as diffracted light at the lens HOE to converge. In other words, in the example of Fig. 20 incident light is partially lost (greater than that in the example of the upper left drawing of Fig. 19). (Configuration, operation and effect of a fiber optic device, a display device and a display system)

[0096] The light guide device according to the present technique may be provided, for example, with a light guide system including an optical element formed as a contact lens or embedded in the eyeball. The contact lens optical element is attached to the surface of an eyeball (for example, a cornea). The eyeball-embedded optical element is embedded in an eyeball (for example, a crystalline lens). The display device according to the present technique may be provided with the light guide device and the image projection device (light source device) that projects image light onto the optical element formed as a contact lens or embedded in the eyeball of the light guide system of the light guide device. The display device may be of a head-mounted type. The image projection device may be configured, for example, with a light source and a projection optical system.In the present technique, a substrate (for example, a light guide plate) can also be used as in the display device of a fifth embodiment described later according to the present technique. A configuration for implementing the light guide device according to the present technique should not be limited to a specific configuration.

[0097] In the present technique, light (light beam) is projected from the image projection device (light source device) onto the second diffraction element (for example, the lens HOE). The light projected onto the second diffraction element passes through the second diffraction element (for example, the lens HOE), such as in the light guide device of a sixth embodiment or the light guide device of a seventh embodiment described later according to the present technique, and then enters the first diffraction element at a different angle from the optical axis of the lens function of the second diffraction element. The incident light beam is reflected and diffracted by a periodic structure provided in the first diffraction element in an arbitrary direction different from the optical axis of the lens function of the second diffraction element.The reflected and diffracted light enters the second diffraction element.

[0098] The incident light beam can be reflected and diffracted by the periodic structure provided in the second diffraction element in a direction that converges (or disperses) light with the optical axis of the lens provided almost vertically with respect to a contact lens surface by the lens function of the second diffraction element.

[0099] The optical axis component of the light reflected and diffracted by the second diffraction element re-enters the first diffraction element. However, the reflection-diffraction effect of the periodic structure provided in the first diffraction element does not occur, so the optical axis component of the light reflected and diffracted by the second diffraction element is transmitted without being diffracted. The transmitted light passes through an eyeball and is incident on a retina.

[0100] In the light incident on the eyeball, light along the optical axis of the lens of the second diffractive element reaches the fovea centralis of the eyeball. Thus, the amount of light in an image does not decrease at a central area of ​​a displayed image, enabling a display at the fovea centralis.

[0101] The optical axis of the second diffractive element (for example, the lens HOE) and the perpendicular line of the first diffractive element (deflection HOE) may be parallel to each other.

[0102] The optical axis of the second diffractive element (for example, the lens HOE) and the perpendicular line of the first diffractive element (deflection HOE) cannot be parallel.

[0103] Light projected onto the first diffraction element (e.g., the deflection HOE) at a predetermined angle of incidence may be light emitted from the light source device and transmitted through the second diffraction element (e.g., the lens HOE).

[0104] The light guide system further comprises a light guide plate disposed at least partially between the first and second diffractive elements (e.g., the deflection HOE and the lens HOE) and guiding light from the light source device. Light projected onto the first diffractive element (e.g., the deflection HOE) at a predetermined angle of incidence may be light emitted by the light source device and guided through the light guide plate.

[0105] The first diffraction element (for example, the deflection HOE) can reflect and diffract light projected onto the first diffraction element at a predetermined angle of incidence in the regular reflection direction.

[0106] The first diffraction element (for example, the deflection HOE) can reflect and diffract light projected onto the first diffraction element at a predetermined angle of incidence in the direction of incidence.

[0107] The first diffraction element (for example, the deflection HOE) can reflect and diffract light projected onto the first diffraction element at a predetermined angle of incidence in a direction different from both the regular reflection direction and the incidence direction.

[0108] At least one of the first and second diffractive elements (for example, the deflection HOE and the lens HOE) may have a curved element surface.

[0109] The light source device and the light guide device may be provided integrally. For example, a self-emissive display element may be mounted in the optical element comprising the first and second diffraction elements.

[0110] The display device according to the present technique may be configured with the light guide device according to the present technique and the light source device that projects light into the light guide device.

[0111] The display device according to the present technique may be configured with the display device according to the present technique and a controller that controls the display device.

[0112] Hereinafter, preferred embodiments for implementing the present technique will be described in detail with reference to the drawings. In the following embodiments, examples of representative embodiments of the present technique are described, and the scope of the present technique should not be narrowly interpreted based on the embodiments. <3. Optical fiber device of the first embodiment of the present technique>

[0113] With reference to Fig. 21, a light guide device according to a first embodiment of the present technique will be described below.

[0114] Fig. Figure 21 illustrates a configuration example of the optical fiber device of the first embodiment according to the present technique. In particular, Fig. 21A a light guide device 1-1 and illustrates Fig. 21B a light guide device 1-2. (Fiber optic device 1-1)

[0115] The light guide device 1-1 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that oppose each other. In the light guide device 1-1, an image is formed based on image display light (display light) L3-1A that passes through the first diffraction element 10 and is emitted from the light guide device 1-1. In the light guide device 1-1, the first diffraction element 10 and the second diffraction element 20 can be arranged close to each other.

[0116] Each of the first diffraction element 10 and the second diffraction element 20 may be any one of a volume hologram optical element, a diffraction grating optical element, and a metasurface optical element.

[0117] The first diffraction element 10 has a deflection function for deflecting incident light L0-1A to the entrance side of the incident light L0-1A on the first diffraction element 10. The incident light L0-1A having a predetermined wavelength is projected onto the first diffraction element 10 by the second diffraction element 20 at a predetermined angle of incidence deviating from the optical axis of a lens. The first diffraction element 10 emits first diffracted light L1-1A deflected by the deflection function.

[0118] As in Fig. 21A, in the three-dimensional coordinate system of the light guide device 1-1, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 21A), the upper surface (the upper surface in Fig. 21A) of the first diffraction element 10 forms an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-1A on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 21A), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing) and in the region of the third quadrant or on the -x-axis (a left axis in the drawing). The first diffracted light L1-1A emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z-axis direction (upper direction in Fig. 21A), in the region of the first quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the fourth quadrant, on the +x-axis (a right axis in the drawing), on the +y-axis (an axis from the near side to the far side in the drawing), or on the -y-axis (an axis from the far side to the near side in the drawing). The light is deflected in the regular reflection direction with respect to the incident light L0-1A.

[0119] The second diffraction element 20 has a lens function for the first diffracted light L1-1A projected onto the second diffraction element 20 at a predetermined wavelength and a predetermined angle of incidence. The lens function means a function of converging (convex lens) or dispersing (concave lens) light (light beam) (as hereinafter referred to as a lens function).

[0120] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-1A to the incident side of the first diffracted light L1-1A on the second diffraction element 20. The first diffracted light L1-1A having a predetermined wavelength is projected onto the second diffraction element 20 at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-1A deflected by the deflection function. The second diffracted light L2-1A is converged by the lens function and re-enters the first diffraction element 10. At this point, the first diffraction element 10 does not have the effect of deflecting light in the direction of the optical axis of the lens.Thus, the second diffracted light L2-1A passes through the first diffraction element 10 and reaches a retina as image display light L3-1A, thereby preventing dimming and invisibility in the center of a display field of view, the center corresponding to the optical axis of the lens.

[0121] Furthermore, in the light guide device 1-1, the direction of the angle of incidence of the incident light L0-1A and the direction of the angle of diffraction of the first diffracted light L1-1A are different from the direction of the optical axis of the second diffraction element 20. (Fiber optic device 1-2)

[0122] The light guide device 1-2 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that oppose each other. In the light guide device 1-2, an image is formed based on image display light (display light) L3-1B that passes through the first diffraction element 10 and is emitted from the light guide device 1-2. As shown in Fig. 21B, in the light guide device 1-2, the first diffraction element 10 and the second diffraction element 20 are arranged in contact.

[0123] The first diffraction element 10 has a deflection function for deflecting incident light L0-1B to the entrance side of the incident light L0-1B on the first diffraction element 10. The incident light L0-1B having a predetermined wavelength is projected onto the first diffraction element 10 by the second diffraction element 20 at a predetermined angle of incidence deviating from the optical axis of a lens function. The first diffraction element 10 emits first diffracted light L1-1B deflected by the deflection function.

[0124] As in Fig. 21B, in the three-dimensional coordinate system of the light guide device 1-2, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 21B), the upper surface (the upper surface in Fig. 21B) of the first diffraction element 10 forms an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-1B on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 21B), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), and in the region of the third quadrant or on the -x-axis (a left axis in the drawing). The first diffracted light L1-1B emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z-axis direction, in the region of the first quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the fourth quadrant, on the +x-axis (a right axis in the drawing), on the +y-axis (an axis from the near side to the far side in the drawing), or on the -y-axis (an axis from the far side to the near side in the drawing).The light is deflected in the regular reflection direction with respect to the incident light L0-1B.

[0125] The second diffraction element 20 has a lens function for the first diffracted light L1-1B projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0126] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-1B to the incident side of the first diffracted light L1-1B on the second diffraction element 20, wherein the first diffracted light L1-1B is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-1B deflected by the deflection function.

[0127] In the light guide device 1-2, the direction of the angle of incidence of the incident light L0-1B and the direction of the angle of diffraction of the first diffracted light L1-1B are different from the direction of the optical axis of the second diffraction element 20.

[0128] The contents of the optical fiber device according to the first embodiment of the present technique can be applied to the following optical fiber devices according to the second to eleventh embodiments of the present technique, unless technical contradictions occur. <4. Optical fiber device of the second embodiment of the present technique>

[0129] With reference to Fig. 22, a light guide device according to a second embodiment of the present technique will be described below. In the light guide device according to the second embodiment of the present technique, a first diffraction element has the function of deflecting light in an incident direction and reflecting and diffracting the light after the light is projected onto the first diffraction element by a second diffraction element at an angle deviating from the optical axis of a lens. Examples of the first diffraction element and the second diffraction element include a volume HOE.

[0130] Fig. 22 illustrates a configuration example of the optical fiber device according to the second embodiment of the present technique. In particular, Fig. 22 a light guide device 2. (Fiber optic device 2)

[0131] The light guide device 2 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that are opposite to each other. In the light guide device 2, an image is formed based on image display light (display light) L3-2 that passes through the first diffraction element 10 and is emitted from the light guide device 2. In the light guide device 2, the first diffraction element 10 and the second diffraction element 20 may be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 may be arranged in contact, which in Fig. 22 is not illustrated.

[0132] The first diffraction element 10 has a deflection function for deflecting incident light L0-2 to the entrance side of the incident light L0-2 on the first diffraction element 10. The incident light L0-2 having a predetermined wavelength is projected onto the first diffraction element 10 by the second diffraction element 20 at a predetermined angle of incidence deviating from the optical axis of a lens. The first diffraction element 10 emits first diffracted light L1-2 deflected by the deflection function.

[0133] As in Fig. 22, in the three-dimensional coordinate system of the light guide device 2, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 22), the upper surface (the upper surface in Fig. 22) of the first diffraction element 10 forms an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-2 on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 22), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing) and in the region of the third quadrant or on the -x axis (a left axis in the drawing). The first diffracted light L1-2 emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z axis direction, in the region of the second quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the third quadrant or on the -x axis (a left axis in the drawing). The light is deflected in the incident direction with respect to the incident light L0-2.

[0134] The second diffraction element 20 has a lens function for the first diffracted light L1-2, which is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0135] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-2 to the incident side of the first diffracted light L1-2 on the second diffraction element 20, wherein the first diffracted light L1-2 is projected onto the second diffraction element 20 at a predetermined wavelength. The second diffraction element 20 emits second diffracted light L2-2 deflected by the deflection function.

[0136] Furthermore, in the light guide device 2, the direction of the angle of incidence of the incident light L0-2 and the direction of the angle of diffraction of the first diffracted light L1-2 are different from the direction of the optical axis of the second diffraction element 20.

[0137] The contents of the optical fiber device according to the second embodiment of the present technique can be applied to the optical fiber device according to the first embodiment of the present technique and the following optical fiber devices according to the third to eleventh embodiments of the present technique, unless technical contradictions occur. <5. Optical fiber device of the third embodiment of the present technique>

[0138] With reference to Fig. 23, a light guide device according to a third embodiment of the present technique will be described below. A feature of the light guide device according to the third embodiment of the present technique is that a light beam entering a first diffraction element forms an angle different from the angle of a light beam entering a second diffraction element and the angle of a light beam diffracted by the second diffraction element. Thus, in the case of a configuration in which a light beam passes through the second diffraction element and enters the first diffraction element, the light guide device does not have the effect of converging (convex lens effect) or dispersing (concave lens effect) a light beam incident on the second diffraction element, and reflecting and diffracting the light beam.This allows the light beam to pass through and hit the second diffraction element.

[0139] Fig. 23 illustrates a configuration example of the optical fiber device according to the third embodiment of the present technique. In particular, Fig. 23A a light guide device 3-1 and illustrates Fig. 23B a light guide device 3-2. (Fiber optic device 3-1)

[0140] The light guide device 3-1 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that oppose each other. In the light guide device 3-1, an image is formed based on image display light (display light) L3-3A that passes through the first diffraction element 10 and is emitted from the light guide device 2. In the light guide device 3-1, the first diffraction element 10 and the second diffraction element 20 may be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 may be arranged in contact, which in Fig. 23A is not illustrated.

[0141] The first diffraction element 10 has a deflection function of deflecting incident light L0-3A onto the entrance side of the incident light L0-3A on the first diffraction element 10, wherein the incident light L0-3A is projected onto the first diffraction element 10 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-3A deflected by the deflection function.

[0142] As in Fig. 23A, in the three-dimensional coordinate system of the light guide device 3-1, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 23A), the upper surface (the upper surface in Fig. 23A) of the first diffraction element 10 forms an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-3A on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 23A), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), and in the region of the third quadrant or on the -x axis (a left axis in the drawing). The first diffracted light L1-3A emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z axis direction, in the region of the second quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the third quadrant, or on the -x axis (a left axis in the drawing). The light is deflected in a direction different from the regular reflection direction and the incidence direction with respect to the incident light L0-3A.

[0143] The second diffraction element 20 has a lens function for the first diffracted light L1-3A projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0144] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-1B to the incident side of the first diffracted light L1-3A on the second diffraction element 20, wherein the first diffracted light L1-3A is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-3A deflected by the deflection function.

[0145] Furthermore, in the light guide device 3-1, the direction of the angle of incidence of the incident light L0-3A and the direction of the angle of diffraction of the first diffracted light L1-3A are different from the direction of the optical axis of the second diffraction element 20. (Fiber optic device 3-2)

[0146] The light guide device 3-2 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that are opposite to each other. In the light guide device 3-2, an image is formed based on image display light (display light) L3-3B that passes through the first diffraction element 10 and is emitted from the light guide device 3-2. In the light guide device 3-2, the first diffraction element 10 and the second diffraction element 20 may be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 may be arranged in contact, which in Fig. 23B is not illustrated.

[0147] The first diffraction element 10 has a deflection function of deflecting incident light L0-3B to the entrance side of the incident light L0-3B on the first diffraction element 10, wherein the incident light L0-3B is projected onto the first diffraction element 10 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-3B deflected by the deflection function.

[0148] As in Fig. 23B, in the three-dimensional coordinate system of the light guide device 3-2, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 23B), the upper surface (the upper surface in Fig. 23B) of the first diffraction element 10 is an xy plane (a plane extending from the near side to the far side in the drawing), the incident light L0-3B on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 23B), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing) and in the region of the third quadrant or on the -x-axis (a left axis in the drawing). The first diffracted light L1-3B emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z-axis direction (upward direction in Fig. 23B), in the region of the first quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the fourth quadrant, on the +x-axis (a right axis in the drawing), on the +y-axis (an axis from the near side to the far side in the drawing), or on the -y-axis (an axis from the far side to the near side in the drawing). The light is deflected in a direction that is different from both the incident direction and the regular reflection direction with respect to the incident light L0-3B.

[0149] The second diffraction element 20 has a lens function for the first diffracted light L1-3B projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0150] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-3B to the incident side of the first diffracted light L1-3B on the second diffraction element 20, wherein the first diffracted light L1-3B is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-3B deflected by the deflection function.

[0151] Furthermore, in the light guide device 3-2, the direction of the angle of incidence of the incident light L0-3B and the direction of the angle of diffraction of the first diffracted light L1-3B are different from the direction of the optical axis of the second diffraction element 20.

[0152] The contents of the optical fiber device according to the third embodiment of the present technique can be applied to the optical fiber devices according to the first and second embodiments of the present technique and the following optical fiber devices according to the fourth to eleventh embodiments of the present technique, unless technical contradictions occur. <6. Optical fiber device of the fourth embodiment of the present technique>

[0153] With reference to Fig. 24, a light guide device according to a fourth embodiment of the present technique will be described below. In the light guide device according to the fourth embodiment of the present technique, a feature is that the optical axis of the lens of a second diffraction element tilts from a vertical line with respect to the second diffraction element.

[0154] Fig. 24 illustrates a configuration example of the optical fiber device according to the fourth embodiment of the present technique. In particular, Fig. 24A a light guide device 4-1 and illustrates Fig. 24B a light guide device 4-2. (Fiber optic device 4-1)

[0155] The light guide device 4-1 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that oppose each other. In the light guide device 4-1, an image is formed based on image display light (display light) L3-4A that passes through the first diffraction element 10 and is emitted from the light guide device 4-1. In the light guide device 4-1, the first diffraction element 10 and the second diffraction element 20 may be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 may be arranged in contact, which in Fig. 24A is not illustrated.

[0156] The first diffraction element 10 has a deflection function of deflecting incident light L0-4A onto the entrance side of the incident light L0-4A on the first diffraction element 10, wherein the incident light L0-4A having a predetermined wavelength is projected onto the first diffraction element 10 at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-4A deflected by the deflection function.

[0157] As in Fig. 24A, in the three-dimensional coordinate system of the light guide device 4-1, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 24A), the upper surface (the upper surface in Fig. 24A) of the first diffraction element 10 is an xy plane (a plane extending from the near side to the far side in the drawing), the incident light L0-4A on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 24A), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing) and in the region of the third quadrant or on the -x axis (a left axis in the drawing). The first diffracted light L1-4A emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z axis direction, in the region of the second quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the third quadrant or on the -x axis (a left axis in the drawing). The light is deflected in the incident direction with respect to the incident light L0-4A.

[0158] The second diffraction element 20 has a lens function for the first diffracted light L1-4A, which is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0159] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-4A to the incident side of the first diffracted light L1-4A on the second diffraction element 20, wherein the first diffracted light L1-4A is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-4A deflected by the deflection function.

[0160] In the light guide device 4-1, the direction of the angle of incidence of the incident light L0-4A and the direction of the angle of diffraction of the first diffracted light L1-4A are different from the direction of the optical axis of the second diffraction element 20. (Fiber optic device 4-2)

[0161] The light guide device 4-2 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that oppose each other. In the light guide device 4-2, an image is formed based on image display light (display light) L3-4B that passes through the first diffraction element 10 and is emitted from the light guide device 4-2. In the light guide device 4-2, the first diffraction element 10 and the second diffraction element 20 may be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 may be arranged in contact, which in Fig. 24B is not illustrated.

[0162] The first diffraction element 10 has a deflection function of deflecting incident light L0-4B to the entrance side of the incident light L0-4B on the first diffraction element 10, wherein the incident light L0-4B is projected onto the first diffraction element 10 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-4B deflected by the deflection function.

[0163] As in Fig. 24B, in the three-dimensional coordinate system of the light guide device 4-2, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 24B), the upper surface (the upper surface in Fig. 24B) of the first diffraction element 10 forms an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-4B on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 24B), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing) and in the region of the third quadrant or on the -x-axis (a left axis in the drawing). The first diffracted light L1-4B emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z-axis direction (upper direction in Fig. 24B), in the region of the first quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the fourth quadrant, on the +x-axis (a right axis in the drawing), on the +y-axis (an axis from the near side to the far side in the drawing), or on the -y-axis (an axis from the far side to the near side in the drawing). The light is deflected in the regular reflection direction with respect to the incident light L0-4B.

[0164] The second diffraction element 20 has a lens function for the first diffracted light L1-4B projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0165] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-4B to the incident side of the first diffracted light L1-4B on the second diffraction element 20, wherein the first diffracted light L1-4B is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-4B deflected by the deflection function.

[0166] In the light guide device 4-2, the direction of the angle of incidence of the incident light L0-4B and the direction of the angle of diffraction of the first diffracted light L1-4B are different from the direction of the optical axis of the second diffraction element 20.

[0167] The contents of the optical fiber device according to the fourth embodiment of the present technique can be applied to the optical fiber devices according to the first to third embodiments of the present technique and the following optical fiber devices according to the fifth to eleventh embodiments of the present technique, unless technical contradictions occur. <7. Optical fiber device of the fifth embodiment of the present technique>

[0168] With reference to Fig. 25, a light guide device according to a fifth embodiment of the present technique will be described below. A feature of the light guide device according to the fifth embodiment of the present technique is the provision of a substrate (e.g., a light guide plate or a GRIN lens) in contact with a first diffraction element. For example, the substrate (e.g., a light guide plate or a GRIN lens) may be provided between the first diffraction element and a second diffraction element. The substrate (e.g., a light guide plate or a GRIN lens) guides light incident on the first diffraction element, the guided light is deflected to be reflected and diffracted by a first optical element, and the light is reflected and diffracted by a lens through a second diffraction element.

[0169] Fig. 25 illustrates a configuration example of the optical fiber device according to the fifth embodiment of the present technique. In particular, Fig. 25 a light guide device 5. (Fiber optic device 5)

[0170] The light guide device 5 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that oppose each other. In the light guide device 5, an image is formed based on image display light (display light) L3-5 that passes through the first diffraction element 10 and is emitted from the light guide device 5.

[0171] A light guide plate 500 is provided between the first diffraction element 10 and the second diffraction element 20. In the light guide plate 500, light L0-5-1, light L0-5-2, and light L05-3 are sequentially propagated while being reflected. Light L05-3 is projected as incident light into the first diffraction element 10.

[0172] The first diffraction element 10 has a deflection function of deflecting incident light L0-5-3 to the entrance side of the incident light L0-5-3 on the first diffraction element 10, wherein the incident light L0-5-3 is projected onto the first diffraction element 10 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-5 deflected by the deflection function.

[0173] As in Fig. 25, in the three-dimensional coordinate system of the light guide device 5, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 25), the upper surface (the upper surface in Fig. 25) of the first diffraction element 10 is an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-5-3 on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 25), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), and in the region of the third quadrant or on the -x axis (a left axis in the drawing). The first diffracted light L1-5 emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z axis direction, in the region of the second quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the third quadrant, or on the -x axis (a left axis in the drawing). The light is deflected in a direction different from the regular reflection direction and the incidence direction with respect to the incident light L0-5-3.

[0174] The second diffraction element 20 has a lens function for the first diffracted light L1-5 projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0175] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-5 to the incident side of the first diffracted light L1-5 on the second diffraction element 20, wherein the first diffracted light L1-5 is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-5 deflected by the deflection function.

[0176] In the light guide device 5, the direction of the angle of incidence of the incident light L0-5-3 and the direction of the angle of diffraction of the first diffracted light L1-5 are different from the direction of the optical axis of the second diffraction element 20.

[0177] The contents of the optical fiber device according to the fifth embodiment of the present technique can be applied to the optical fiber devices according to the first to fourth embodiments of the present technique and the following optical fiber devices according to the sixth to eleventh embodiments of the present technique, unless technical contradictions occur. <8. Optical fiber device of the sixth embodiment of the present technique>

[0178] With reference to Fig. 26, a light guide device according to a sixth embodiment of the present technique will be described below.

[0179] Fig. 26 illustrates a configuration example of the optical fiber device according to the sixth embodiment of the present technique. In particular, Fig. 26 a light guide device 6. (Light guide device 6)

[0180] The light guide device 6 includes at least one optical element configured with a first diffraction element 10-1 and a second diffraction element 20-1 that are opposite to each other. In the light guide device 6, an image is formed based on image display light (display light) L3-6 that passes through the first diffraction element 10-1 and is emitted from the light guide device 6. In the light guide device 6, the first diffraction element 10-1 and the second diffraction element 20-1 can be arranged close to each other. The first diffraction element 10-1 and the second diffraction element 20-1 can be arranged in contact, which in Fig. 26 is not illustrated.

[0181] Each of the first diffraction element 10-1 and the second diffraction element 20-1 may be any one of a volume hologram optical element, a diffraction grating optical element, and a metasurface optical element.

[0182] In the light guide device 6, the first diffraction element 10-1 has a curved shape such that an upwardly projecting shape T1-6 is formed substantially at the central portion of the first diffraction element 10-1, and the second diffraction element 20-1 has a curved shape such that an upwardly projecting shape T2-6 is formed substantially at the central portion of the second diffraction element 20-1.

[0183] The first diffraction element 10-1 has a deflection function of deflecting incident light L0-6 to the entrance side of the incident light L0-6 on the first diffraction element 10. The incident light L0-6 is projected onto the first diffraction element 10-1 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10-1 emits first diffracted light L1-6 deflected by the deflection function.

[0184] As in Fig. 26, in the three-dimensional coordinate system of the light guide device 6, the normal of the first diffraction element 10-1 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 26), the upper surface (the upper surface in Fig. 26) of the first diffraction element 10-1 is an xy plane (a plane extending from the near side to the far side in the drawing) (when the upwardly projecting shape T1-6 is formed at a low protrusion level, the xy plane can approach the upper surface of the first diffraction element 10 as follows, whereas when the upwardly projecting shape T1-6 is formed at a high protrusion level, the xy plane comes into contact with the origin of the three-dimensional coordinate system in the region of the upper surface of the first diffraction element 10-1). The incident light L0-6 on the first diffraction element 10-1 is light directed to the origin of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 26), in the area of ​​the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing) and in the area of ​​the third quadrant or on the -x-axis (a left axis in the drawing). The first diffracted light L1-6 emitted from the first diffraction element 10-1 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z-axis direction (upward direction in Fig. 26), in the region of the first quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the fourth quadrant, on the +x-axis (a right axis in the drawing), on the +y-axis (an axis from the near side to the far side in the drawing), or on the -y-axis (an axis from the far side to the near side in the drawing). The light is deflected in the regular reflection direction with respect to the incident light L0-6.

[0185] The second diffraction element 20-1 has a lens function for the first diffracted light L1-6 projected onto the second diffraction element 20-1 at a predetermined wavelength and at a predetermined angle of incidence.

[0186] The second diffraction element 20-1 has a deflection function of deflecting the first diffracted light L1-6 to the incident side of the first diffracted light L1-6 on the second diffraction element 20-1, wherein the first diffracted light L1-6 is projected onto the second diffraction element 20-1 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20-1 emits second diffracted light L2-6 deflected by the deflection function.

[0187] In the light guide device 6, the direction of the angle of incidence of the incident light L0-6 and the direction of the angle of diffraction of the first diffracted light L1-6 are different from the direction of the optical axis of the second diffraction element 20-1.

[0188] The contents of the optical fiber device according to the sixth embodiment of the present technique can be applied to the optical fiber devices according to the first to fifth embodiments of the present technique and the following optical fiber devices according to the seventh to eleventh embodiments of the present technique, unless technical contradictions occur. <9. Optical fiber device of the seventh embodiment of the present technique>

[0189] With reference to Fig. 27, a light guide device according to a seventh embodiment of the present technique will be described below.

[0190] Fig. 27 illustrates a configuration example of the optical fiber device according to the seventh embodiment of the present technique. In particular, Fig. 27 a light guide device 7. (Light guide device 7)

[0191] The light guide device 7 includes at least one optical element configured with a first diffraction element 10-1 and a second diffraction element 20-1 that are opposite to each other. In the light guide device 7, an image is formed based on image display light (display light) L3-7 that passes through the first diffraction element 10-1 and is emitted from the light guide device 7. In the light guide device 7, the first diffraction element 10-1 and the second diffraction element 20-1 may be arranged close to each other. The first diffraction element 10-1 and the second diffraction element 20-1 may be arranged in contact, which in Fig. 27 is not illustrated.

[0192] In the light guide device 7, the first diffraction element 10-1 has a curved shape such that an upwardly projecting shape T1-7 is formed substantially at the central portion of the first diffraction element 10-1, and the second diffraction element 20-1 has a curved shape such that an upwardly projecting shape T2-7 is formed substantially at the central portion of the second diffraction element 20-1.

[0193] The first diffraction element 10-1 has a deflection function of deflecting incident light L0-7 to the entrance side of the incident light L0-7 on the first diffraction element 10. The incident light L0-7 is projected onto the first diffraction element 10-1 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10-1 emits first diffracted light L1-7 deflected by the deflection function.

[0194] As in Fig. 27, in the three-dimensional coordinate system of the light guide device 7, the normal of the first diffraction element 10-1 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 27) and is the upper surface (the upper surface in Fig. 27) of the first diffraction element 10-1 forms an xy plane (a plane extending from the near side to the far side in the drawing) (when the upwardly projecting shape T1-7 is formed at a low protrusion level, the xy plane can approach the upper surface of the first diffraction element 10-1 as follows, whereas when the upwardly projecting shape T1-7 is formed at a high protrusion level, the xy plane comes into contact with the origin of the three-dimensional coordinate system in the region of the upper surface of the first diffraction element 10-1). The incident light L0-7 on the first diffraction element 10-1 is light incident on the origin of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 27), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing) and in the region of the third quadrant or on the -x axis (a left axis in the drawing). The first diffracted light L1-7 emitted from the first diffraction element 10-1 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z axis direction, in the region of the second quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the third quadrant or on the -x axis (a left axis in the drawing). The light is deflected in the incident direction with respect to the incident light L0-7.

[0195] The second diffraction element 20-1 has a lens function for the first diffracted light L1-7 projected onto the second diffraction element 20-1 at a predetermined wavelength and at a predetermined angle of incidence.

[0196] The second diffraction element 20-1 has a deflection function of deflecting the first diffracted light L1-7 to the incident side of the first diffracted light L1-7 on the second diffraction element 20-1, wherein the first diffracted light L1-7 is projected onto the second diffraction element 20-1 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20-1 emits second diffracted light L2-7 deflected by the deflection function.

[0197] In the light guide device 7, the direction of the angle of incidence of the incident light L0-7 and the direction of the angle of diffraction of the first diffracted light L1-7 are different from the direction of the optical axis of the second diffraction element 20-1.

[0198] The contents of the optical fiber device according to the seventh embodiment of the present technique can be applied to the optical fiber devices according to the first to sixth embodiments of the present technique and the following optical fiber devices according to the eighth to eleventh embodiments of the present technique, unless technical contradictions occur. <10. Optical fiber device of the eighth embodiment of the present technique>

[0199] With reference to Fig. 28, a light guide device according to an eighth embodiment of the present technique will be described below. In the light guide device according to the eighth embodiment of the present technique, a first diffraction element is a HOE that not only deflects light but also diffracts light in a substantially regular reflection direction with any optical aberration (a dispersing or converging effect, or a wavefront correcting effect), and a second diffraction element is a reflection lens HOE that converges or disperses an incident light beam (diffracted light beam) from the first diffraction element.

[0200] Fig. 28 illustrates a configuration example of the optical fiber device according to the eighth embodiment of the present technique. In particular, Fig. 28 a light guide device 8. (Light guide device 8)

[0201] The light guide device 8 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that are opposite to each other. In the light guide device 8, an image is formed based on image display light (display light) L3-8 that passes through the first diffraction element 10 and is emitted from the light guide device 8. In the light guide device 8, the first diffraction element 10 and the second diffraction element 20 can be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 can be arranged in contact, which in Fig. 28 is not illustrated.

[0202] The first diffraction element 10 has a deflection function of deflecting incident light L0-8 to the entrance side of the incident light L0-8 on the first diffraction element 10, wherein the incident light L0-8 is projected onto the first diffraction element 10 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-8 deflected by the deflection function.

[0203] As in Fig. 28, in the three-dimensional coordinate system of the light guide device 8, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 28), the upper surface (the upper surface in Fig. 28) of the first diffraction element 10 is an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-8 on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 28), in the area of ​​the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing) and in the area of ​​the third quadrant or on the -x-axis (a left axis in the drawing). The first diffracted light L1-8 emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z-axis direction (upper direction in Fig. 28), in the region of the first quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the fourth quadrant, on the +x-axis (a right axis in the drawing), on the +y-axis (an axis from the near side to the far side in the drawing), or on the -y-axis (an axis from the far side to the near side in the drawing). The light is deflected in the regular reflection direction with respect to the incident light L0-8.

[0204] The second diffraction element 20 has a lens function for the first diffracted light L1-8, which is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0205] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-8 to the incident side of the first diffracted light L1-8 on the second diffraction element 20, wherein the first diffracted light L1-8 is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-8 deflected by the deflection function.

[0206] In the light guide device 8, the direction of the angle of incidence of the incident light L0-8 and the direction of the angle of diffraction of the first diffracted light L1-8 are different from the direction of the optical axis of the second diffraction element 20.

[0207] The contents of the optical fiber device according to the eighth embodiment of the present technique can be applied to the optical fiber devices according to the first to seventh embodiments of the present technique and the following optical fiber devices according to the ninth to eleventh embodiments of the present technique, unless technical contradictions occur. <11. Optical fiber device of the ninth embodiment of the present technique>

[0208] With reference to Fig. 29, a light guide device according to a ninth embodiment of the present technique will be described below. In the light guide device according to the ninth embodiment of the present technique, a first diffraction element is a HOE that not only deflects light but also diffracts light in an incident direction or a direction different from the incident direction and a regular reflection direction with any optical aberration (a dispersing or converging effect, or a wavefront correcting effect), and a second diffraction element is a reflection lens HOE that converges or disperses an incident light beam (diffracted light beam) from the first diffraction element.

[0209] Fig. 29 illustrates a configuration example of the optical fiber device according to the ninth embodiment of the present technique. In particular, Fig. 29 a light guide device 9. (Light guide device 9)

[0210] The light guide device 9 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that are opposite to each other. In the light guide device 9, an image is formed based on image display light (display light) L3-9 that passes through the first diffraction element 10 and is emitted from the light guide device 9. In the light guide device 9, the first diffraction element 10 and the second diffraction element 20 can be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 can be arranged in contact, which in Fig. 29 is not illustrated.

[0211] The first diffraction element 10 has a deflection function of deflecting incident light L0-9 to the entrance side of the incident light L0-9 on the first diffraction element 10, wherein the incident light L0-9 is projected onto the first diffraction element 10 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-9 deflected by the deflection function.

[0212] As in Fig. 29, in the three-dimensional coordinate system of the light guide device 9, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 29), the upper surface (the upper surface in Fig. 29) of the first diffraction element 10 is an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-9 on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 29), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), and in the region of the third quadrant or on the -x axis (a left axis in the drawing). The first diffracted light L1-9 emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z axis direction, in the region of the second quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the third quadrant, or on the -x axis (a left axis in the drawing). The light is deflected in a direction different from the regular reflection direction and the incidence direction with respect to the incident light L0-9.

[0213] The second diffraction element 20 has a lens function for the first diffracted light L1-9, which is projected onto the second diffraction element 20 at a predetermined wavelength at a predetermined angle of incidence.

[0214] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-9 to the incident side of the first diffracted light L1-9 on the second diffraction element 20, wherein the first diffracted light L1-9 is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-9 deflected by the deflection function.

[0215] In the light guide device 9, the direction of the angle of incidence of the incident light L0-9 and the direction of the angle of diffraction of the first diffracted light L1-9 are different from the direction of the optical axis of the second diffraction element 20.

[0216] The contents of the optical fiber device according to the ninth embodiment of the present technique can be applied to the optical fiber devices according to the first to eighth embodiments of the present technique and the following optical fiber devices according to the tenth and eleventh embodiments of the present technique, unless technical contradictions occur. <12. Optical fiber device of the tenth embodiment of the present technique>

[0217] With reference to Fig. 30, a light guide device according to a tenth embodiment of the present technique will be described below. A feature of the light guide device according to the tenth embodiment of the present technique is that a light beam entering a first diffraction element forms an angle different from the angle of a light beam entering a second diffraction element and the angle of a light beam diffracted by the second diffraction element. Another feature is that the optical axis of the lens of the second diffraction element tilts from a vertical line with respect to the second diffraction element.Thus, in the case of a configuration where a light beam passes through the second diffraction element and enters the first diffraction element, the light guide device does not have the effect of converging (convex lens) or dispersing (concave lens) a light beam incident on the second diffraction element, nor of reflecting and diffracting the light beam. This allows the light beam incident on the second diffraction element to pass through.

[0218] Fig. 30 illustrates a configuration example of the optical fiber device according to the tenth embodiment of the present technique. In particular, Fig. 30 a light guide device 12. (Light guide device 12)

[0219] The light guide device 12 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that are opposite to each other. In the light guide device 12, an image is formed based on image display light (display light) L3-12 that passes through the first diffraction element 10 and is emitted from the light guide device 12. In the light guide device 12, the first diffraction element 10 and the second diffraction element 20 can be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 can be arranged in contact, which in Fig. 30 is not illustrated.

[0220] The first diffraction element 10 has a deflection function of deflecting incident light L0-12 onto the entrance side of the incident light L0-12 on the first diffraction element 10, wherein the incident light L0-12 is projected onto the first diffraction element 10 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-12 deflected by the deflection function.

[0221] As in Fig. 30, in the three-dimensional coordinate system of the light guide device 12, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 30), the upper surface (the upper surface in Fig. 30) of the first diffraction element 10 forms an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-12 on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 30), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), and in the region of the third quadrant or on the -x axis (a left axis in the drawing). The first diffracted light L1-12 emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z axis direction, in the region of the second quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the third quadrant, or on the -x axis (a left axis in the drawing). The light is deflected in a direction different from the regular reflection direction and the incidence direction with respect to the incident light L0-12.

[0222] The second diffraction element 20 has a lens function for the first diffracted light L1-12, which is projected onto the second diffraction element 20 at a predetermined wavelength at a predetermined angle of incidence.

[0223] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-12 to the incident side of the first diffracted light L1-12 on the second diffraction element 20, wherein the first diffracted light L1-12 is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-12 deflected by the deflection function.

[0224] In the light guide device 12, the direction of the angle of incidence of the incident light L0-12 and the direction of the angle of diffraction of the first diffracted light L1-12 are different from the direction of the optical axis of the second diffraction element 20.

[0225] The contents of the optical fiber device according to the tenth embodiment of the present technique can be applied to the optical fiber devices according to the first to ninth embodiments of the present technique and a subsequently mentioned optical fiber device according to an eleventh embodiment of the present technique, unless technical contradictions occur. <13. Optical fiber device of the eleventh embodiment of the present technique>

[0226] With reference to Fig. 31, a light guide device according to an eleventh embodiment of the present technique will be described below. A feature of the light guide device according to the eleventh embodiment of the present technique is that the angle of a projected and diffracted light beam of a first diffraction element is larger than the light beam propagation angle of the lens function of a second diffraction element (an incident angle from the first diffraction element to the second diffraction element is larger than FOV / 2). A region where the diffraction efficiency decreases is excluded from an FOV.

[0227] Fig. 31 illustrates a configuration example of the optical fiber device according to the eleventh embodiment of the present technique. In particular, Fig. 31A a light guide device 13-1 and illustrates Fig. 31B a light guide device 13-2. (Light guide device 13-1)

[0228] The light guide device 13-1 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that oppose each other. In the light guide device 13-1, an image is formed based on image display light (display light) L3-13A that passes through the first diffraction element 10 and is emitted from the light guide device 13-1. In the light guide device 13-1, the first diffraction element 10 and the second diffraction element 20 may be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 may be arranged in contact, which in Fig. 31A is not illustrated.

[0229] The first diffraction element 10 has a deflection function of deflecting incident light L0-13A to the entrance side of the incident light L0-13A on the first diffraction element 10, wherein the incident light L0-13A is projected onto the first diffraction element 10 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-13A deflected by the deflection function.

[0230] As in Fig. 31A, in the three-dimensional coordinate system of the light guide device 13-1, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 31A), the upper surface (the upper surface in Fig. 31A) of the first diffraction element 10 is an xy plane (a plane extending from the near side to the far side in the drawing), the incident light L0-13A on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 31A), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), and in the region of the third quadrant or on the -x axis (a left axis in the drawing). The first diffracted light L1-13A emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z axis direction, in the region of the second quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the region of the third quadrant, or on the -x axis (a left axis in the drawing). The light is deflected in a direction different from the regular reflection direction and the incidence direction with respect to the incident light L0-13A.

[0231] The second diffraction element 20 has a lens function for the first diffracted light L1-13A projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0232] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-13A to the incident side of the first diffracted light L1-13A on the second diffraction element 20, wherein the first diffracted light L1-13A is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-13A deflected by the deflection function.

[0233] In the light guide device 13-1, the direction of the angle of incidence of the incident light L0-13A and the direction of the angle of diffraction of the first diffracted light L1-13A are different from the direction of the optical axis of the second diffraction element 20. (Fiber optic device 13-2)

[0234] The light guide device 13-2 includes at least one optical element configured with a first diffraction element 10 and a second diffraction element 20 that oppose each other. In the light guide device 13-2, an image is formed based on image display light (display light) L3-13B that passes through the first diffraction element 10 and is emitted from the light guide device 13-2. In the light guide device 13-2, the first diffraction element 10 and the second diffraction element 20 may be arranged close to each other. The first diffraction element 10 and the second diffraction element 20 may be arranged in contact, which in Fig. 31B is not illustrated.

[0235] The first diffraction element 10 has a deflection function of deflecting incident light L0-13B to the entrance side of the incident light L0-13B on the first diffraction element 10, wherein the incident light L0-13B is projected onto the first diffraction element 10 at a predetermined wavelength and at a predetermined angle of incidence. The first diffraction element 10 emits first diffracted light L1-13B deflected by the deflection function.

[0236] As in Fig. 31B, in the three-dimensional coordinate system of the light guide device 13-2, the normal of the first diffraction element 10 extends from the origin point of the three-dimensional coordinate system in the +z-axis direction (upward direction in Fig. 31B), the upper surface (the upper surface in Fig. 31B) of the first diffraction element 10 forms an xy plane (a plane extending from the near side to the far side in the drawing), and the incident light L0-13B on the first diffraction element 10 is light incident on the origin point of the three-dimensional coordinate system from any point in the +z-axis direction (upward direction in Fig. 31B), in the region of the second quadrant of an xy coordinate system (a coordinate system directed from the near side to the far side in the drawing) and in the region of the third quadrant or on the -x-axis (a left axis in the drawing). The first diffracted light L1-13B emitted from the first diffraction element 10 is light directed from the origin point of the three-dimensional coordinate system to any point in the +z-axis direction (upper direction in Fig. 31B), in the area of ​​the first quadrant of the xy coordinate system (a coordinate system directed from the near side to the far side in the drawing), in the area of ​​the fourth quadrant, on the +x-axis (a right axis in the drawing), on the +y-axis (an axis from the near side to the far side in the drawing), or on the -y-axis (an axis from the far side to the near side in the drawing). The light is deflected in the regular reflection direction with respect to the incident light L0-13B.

[0237] The second diffraction element 20 has a lens function for the first diffracted light L1-13B projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence.

[0238] The second diffraction element 20 has a deflection function of deflecting the first diffracted light L1-13B to the incident side of the first diffracted light L1-13B on the second diffraction element 20, wherein the first diffracted light L1-13B is projected onto the second diffraction element 20 at a predetermined wavelength and at a predetermined angle of incidence. The second diffraction element 20 emits second diffracted light L2-13B deflected by the deflection function.

[0239] In the light guide device 13-2, the direction of the angle of incidence of the incident light L0-13B and the direction of the angle of diffraction of the first diffracted light L1-13B are different from the direction of the optical axis of the second diffraction element 20.

[0240] The contents of the optical fiber device according to the eleventh embodiment of the present technique can be applied to the optical fiber devices according to the first to tenth embodiments of the present technique unless technical contradictions occur. <14. Display device of the twelfth embodiment of the present technique>

[0241] A display device according to a twelfth embodiment of the present technique is a display device including a frame to be attached to a user's head, a light source device (e.g., an image projection device) attached to the frame, and a light guide device including a light guide system having an optical element attached to the surface of an eyeball or embedded in an eyeball, wherein light is emitted from the light source device to the light guide device to display an image on a retina.

[0242] The optical fiber device may be any of the optical fiber devices according to the first to eleventh embodiments of the present technique.

[0243] For example, the light source device may include a display element having a plurality of pixels arranged in a two-dimensional array. The display element may, for example, include a light source array in which light sources (pixels) such as OLEDs (organic light-emitting diodes) are arranged in an array, or may include a light source and image-forming elements (a liquid crystal panel, a digital mirror device, a scanning mirror) that form an image using light from the light source.

[0244] The light source device may comprise an optical system comprising a lens and a mirror in addition to the display element. <15. Display system of the thirteenth embodiment of the present technique>

[0245] With reference to Fig. 32, a display system 1000 according to a fifteenth embodiment of the present technique will be described below. Fig. 32 is a block diagram illustrating the functions of the display system 1000. The display system 1000 includes a display device (e.g., the display device according to the twelfth embodiment) and a controller 170. The controller 170 includes, for example, a signal input unit 1000a, a signal processing unit 1000b, a drive unit 1000c, a power detection unit 1000d, and a power supply 1000e.

[0246] The signal input unit 1000a receives a video signal from a video signal output device (e.g., a smartphone, a personal computer, a storage device, or an imaging device).

[0247] The signal processing unit 1000b processes a video signal input through the signal input unit 1000a and generates a drive signal (modulation signal) for driving the display device.

[0248] The control unit 1000c controls the display device by applying the control signal from the signal processing unit 1000b to the display device.

[0249] The power sensing unit 1000d senses power from the power supply 1000e via a wired or wireless connection and distributes the power to the signal input unit 1000a, the signal processing unit 1000b, the drive unit 1000c, and the display device.

[0250] The power supply 1000e may be a storage battery (e.g., a battery or a secondary battery) or a power generation source (a fuel cell, electromagnetic induction or energy harvesting, or the like).

[0251] It should be noted that embodiments according to the present technique are not limited to the above embodiments and can be modified in various ways without departing from the gist of the present technique. For example, at least one of the first and second diffractive elements may be a DOE (Diffractive Optical Element) or a metamaterial optical element. The present technique is applicable to, for example, a DOE and a metamaterial optical element, as well as an HOE. The optical element including the first and second diffractive elements may include at least one diffractive element in addition to the first and second diffractive elements.

[0252] Furthermore, the effects described in the present specification are merely exemplary and are not intended to be limiting, and other effects may also be provided.

[0253] This technology can also be configured as follows: (1) A light-guiding device comprising a light-guiding system that guides light emitted from a light source device to eyeballs, wherein the light guide system has an optical element comprising first and second diffraction elements that are opposite to each other, light emitted by the light source device and projected onto the first diffraction element at a predetermined angle of incidence is reflected and diffracted at the first diffraction element, the light transmitted through the first diffraction element is reflected and diffracted at the second diffraction element, and the light transmitted through the first diffraction element via the second diffraction element is guided to the eyeballs, the second diffraction element has a lens function, and the first and second diffraction elements vary in refractive index difference and / or thickness. (2) The light guide device according to (1), wherein the first and second diffraction elements vary in terms of the product of a refractive index difference and a thickness. (3) The light guide device according to (1) or (2), wherein a first product as the product of the refractive index difference and the thickness of the first diffraction element is larger than a second product as the product of the refractive index difference and the thickness of the second diffraction element. (4) The light guide device according to any one of (1) to (3), wherein the first and second diffraction elements have different refractive index differences. (5) The light guide device according to any one of (1) to (4), wherein the first diffraction element has a larger refractive index difference than the second diffraction element. (6) The light guide device according to any one of (1) to (5), wherein the first and second diffraction elements have different thicknesses. (7) The light guide device according to any one of (1) to (6), wherein the second diffraction element has a greater thickness than the first diffraction element. (8) The light guide device according to any one of (1) to (7), wherein the first and second diffraction elements vary in refractive index difference and thickness. (9) The light guide device according to any one of (1) to (8), wherein the first diffraction element has a larger refractive index difference than the second diffraction element, and the second diffraction element has a larger thickness than the first diffraction element. (10) The light guide device according to any one of (1) to (9), wherein the first and second diffraction elements are identical in thickness and the first diffraction element has a larger refractive index difference than the second diffraction element. (11) The light guide device according to any one of (1) to (10), wherein the first and second diffraction elements are identical in refractive index difference, and the second diffraction element has a greater thickness than the first diffraction element. (12) The light guide device according to any one of (1) to (11), wherein when the first and second diffraction elements have thicknesses in µm, the first product is 0.2 µm or more and the first diffraction element has a thickness of 1 µm to 100 µm. (13) The light guide device according to any one of (1) to (12), wherein when the first and second diffraction elements have thicknesses in µm, the first product is 0.4 µm or more and the first diffraction element has a thickness of 2 µm to 30 µm. (14) The light guide device according to any one of (1) to (13), wherein when the first and second diffraction elements have thicknesses in µm, the second product is 0.1 µm or less and the second diffraction element has a thickness of 1 µm to 100 µm. (15) The light guide device according to any one of (1) to (14), wherein when the first and second diffraction elements have thicknesses in µm, the second product is 0.02 µm or less and the second diffraction element has a thickness of 10 µm to 40 µm. (16) The light guide device according to any one of (1) to (15), wherein the optical axis of the second diffraction element and the perpendicular line of the first diffraction element are parallel to each other. (17) The light guide device according to any one of (1) to (15), wherein the optical axis of the second diffraction element and the perpendicular line of the first diffraction element are not parallel. (18) The light guide device according to any one of (1) to (17), wherein light projected onto the first diffraction element at the predetermined angle of incidence is light emitted from the light source device and transmitted through the second diffraction element. (19) The light guide device according to any one of (1) to (18), wherein the light guide system further comprises a light guide plate disposed at least partially between the first and second diffraction elements and guides light from the light source device, and light projected onto the first diffraction element at the predetermined angle of incidence is light emitted from the light source device and guided through the light guide plate. (20) The light guide device according to any one of (1) to (19), wherein the first diffraction element reflects and diffracts light projected onto the first diffraction element at the predetermined angle of incidence in a regular reflection direction. (21) The light guide device according to any one of (1) to (19), wherein the first diffraction element reflects and diffracts light projected onto the first diffraction element at the predetermined incident angle in an incident direction. (22) The light guide device according to any one of (1) to (19), wherein the first diffraction element reflects and diffracts light projected onto the first diffraction element at the predetermined angle of incidence in a direction different from both the regular reflection direction and the incidence direction. (23) The light guide device according to any one of (1) to (22), wherein at least one of the first and second diffraction elements has a curved element surface. (24) The light guide device according to any one of (1) to (23), wherein at least one of the first and second diffraction elements is a hologram optical element. (25) A light guide device according to any one of (1) to (24), wherein the optical element is attached to or embedded in the eyeball. (26) A display device comprising: the light guide device according to any one of (1) to (25) and the light source device. (27) The display device according to (26), wherein the light source device and the light guide device are provided integrally. (28) A display device according to (26) or (27), wherein the display device is a head-mounted display. (29) A display system comprising: the display device according to any one of (26) to (28) and a controller that controls the display device. [List of reference symbols]

[0254] 1(1-1, 1-2), 2, 3(3-1, 3-2), 4(4-1, 4-2), 5, 6, 7, 8, 9, 10, 11, 12, 13(13-1, 13-2) 10, 10-1 First diffraction element 20, 20-1 Second diffraction element 500 light guide plate 1000 display system QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2005-148655 A

[0004]

Claims

[1] Light guide device with a light guide system that guides light emitted from a light source device to eyeballs, wherein the light guide system comprises an optical element comprising a first and a second diffraction element which are opposite to each other, light emitted by the light source device and projected at a predetermined angle of incidence onto the first diffraction element is reflected and diffracted at the first diffraction element, the light transmitted through the first diffraction element is reflected and diffracted at the second diffraction element, and the light transmitted through the first diffraction element via the second diffraction element is guided to the eyeballs, the second diffraction element has a lens function and the first and second diffraction elements vary in terms of the refractive index difference and / or the thickness. [2] The light guide device according to claim 1, wherein the first and second diffraction elements vary in a product of a refractive index difference and a thickness. [3] The light guide device according to claim 1, wherein a first product as a product of a refractive index difference and a thickness of the first diffraction element is larger than a second product as a product of a refractive index difference and a thickness of the second diffraction element. [4] The light guide device according to claim 1, wherein the first and second diffraction elements have different refractive index differences. [5] The light guide device according to claim 1, wherein the first diffraction element has a larger refractive index difference than the second diffraction element. [6] The light guide device according to claim 1, wherein the first and second diffraction elements have different thicknesses. [7] The light guide device according to claim 1, wherein the second diffraction element has a greater thickness than the first diffraction element. [8] The light guide device according to claim 1, wherein the first and second diffraction elements vary in refractive index difference and thickness. [9] The light guide device according to claim 1, wherein the first diffraction element has a larger refractive index difference than the second diffraction element and the second diffraction element has a larger thickness than the first diffraction element. [10] The light guide device according to claim 1, wherein the first and second diffraction elements are identical in thickness and the first diffraction element has a larger refractive index difference than the second diffraction element. [11] The light guide device according to claim 1, wherein the first and second diffraction elements are identical in refractive index difference, and the second diffraction element has a greater thickness than the first diffraction element. [12] The light guide device according to claim 3, wherein when the first and second diffraction elements have thicknesses in µm, the first product is 0.2 or more and the first diffraction element has a thickness of 1 µm to 100 µm. [13] The light guide device according to claim 3, wherein when the first and second diffraction elements have thicknesses in µm, the first product is 0.4 or more and the first diffraction element has a thickness of 2 µm to 30 µm. [14] The light guide device according to claim 3, wherein when the first and second diffraction elements have thicknesses in µm, the second product is 0.1 or less and the second diffraction element has a thickness of 1 µm to 100 µm. [15] The light guide device according to claim 3, wherein when the first and second diffraction elements have thicknesses in µm, the second product is 0.02 or less and the second diffraction element has a thickness of 10 µm to 40 µm. [16] The light guide device according to claim 1, wherein an optical axis of the second diffraction element and a perpendicular line of the first diffraction element are parallel to each other. [17] The light guide device according to claim 1, wherein an optical axis of the second diffraction element and a perpendicular line of the first diffraction element are not parallel. [18] The light guide device according to claim 1, wherein light projected onto the first diffraction element at the predetermined angle of incidence is light emitted from the light source device and transmitted through the second diffraction element. [19] The light guide device according to claim 1, wherein the light guide system further comprises a light guide plate disposed at least partially between the first and second diffraction elements and guiding light from the light source device, and light projected onto the first diffraction element at the predetermined angle of incidence is light emitted from the light source device and passed through the light guide plate. [20] The light guide device according to claim 1, wherein the first diffraction element reflects and diffracts light projected onto the first diffraction element at the predetermined angle of incidence in a regular reflection direction. [21] The light guide device according to claim 1, wherein the first diffraction element reflects and diffracts light projected onto the first diffraction element at the predetermined angle of incidence in an incident direction. [22] The light guide device according to claim 1, wherein the first diffraction element reflects and diffracts light projected onto the first diffraction element at the predetermined angle of incidence in a direction different from both a regular reflection direction and an incidence direction. [23] The light guide device according to claim 1, wherein at least one of the first and second diffraction elements has a curved element surface. [24] The light guide device according to claim 1, wherein at least one of the first and second diffraction elements is a hologram optical element. [25] A light-guiding device according to claim 1, wherein the optical element is attached to or embedded in the eyeball. [26] A display device comprising: the light guide device according to claim 1; and the light source device. [27] A display device according to claim 26, wherein the light source device and the light guide device are provided integrally. [28] A display device according to claim 26, wherein the display device is a head-mounted display. [29] A display system comprising: the display device according to claim 26; and a controller that controls the display device.

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