image output device

Abstract

The image output device disclosed herein facilitates the enlargement of stereoscopic images. This image output device includes a spatial modulator, an image illumination unit, and an addressing light illumination unit. The spatial modulator has a main surface, a back surface, and multiple pixels, reflects light illuminating the main surface, and modulates the phase of the light for each pixel. The image illumination unit illuminates light containing a two-dimensional optical image on the main surface. The addressing light illumination unit illuminates addressing light containing a diffraction grating pattern on the back surface. Each pixel of the spatial light modulator changes its phase modulation amount according to the intensity of the addressing light illuminating from the back surface. The addressing light illumination unit is configured such that the direction of the diffraction grating pattern on the back surface dynamically changes. The image illumination unit illuminates a two-dimensional optical image on the main surface corresponding to the direction of the diffraction grating pattern.

Description

Technical Field

[0001] This disclosure relates to an image output device.

[0002] This application claims priority to Japanese Patent Application No. 2020-104562, filed on June 17, 2020, the contents of which are incorporated herein by reference in their entirety. Background Technology

[0003] Non-Patent Document 1 discloses a device for stereoscopically outputting images. This device comprises a high-speed (3600 rpm) rotating holographic screen and a high-speed projector. The high-speed projector is a DLP (Digital Light Processing) projector using a DMD (Digital Micromirror Device). By projecting a two-dimensional optical image onto the holographic screen from the high-speed projector and causing the holographic screen to rotate at high speed, the two-dimensional optical image is deflected along a 360° circumference. The high-speed projector changes the two-dimensional optical image according to the deflection direction generated by the holographic screen. Thus, an observer can stereoscopically view a three-dimensional image.

[0004] Non-Patent Document 2 discloses a technology relating to a light-addressable liquid crystal spatial light modulator (PAL-SLM). This spatial light modulator has an addressing layer and a liquid crystal layer. The addressing layer comprises hydrogenated amorphous silicon as a photoconductor. The liquid crystal layer comprises nematic liquid crystal. The write side and read side are optically separated by a dielectric mirror composed of a multilayer film of SiO2 and TiO2. An alternating voltage of several volts is applied between a pair of transparent electrodes (ITO) sandwiching the addressing layer, and an image (two-dimensional information) is written onto the addressing layer. In areas where no write light is irradiated, the impedance of the hydrogenated amorphous silicon is greater than that of the liquid crystal layer, thus imparting almost no voltage to the liquid crystal layer. On the other hand, in areas where write light is irradiated, the impedance of the hydrogenated amorphous silicon decreases, and the voltage imparted to the liquid crystal layer increases, thereby changing the phase of the read light in the liquid crystal. As described above, the phase of the read light can be modulated two-dimensionally according to the write light information. Furthermore, a partition structure for the liquid crystal layer is disclosed, for example, in Non-Patent Document 3 below.

[0005] Non-patent literature 1: Hideyoshi Horimai et al., “Full-color 3D display system with 360-degree horizontal viewing angle (The International Symposium of 3D and Contents 2010)”, The International Symposium of 3D and Contents 2010, pp.7-10 (2010).

[0006] Non-Patent Literature 2: Tsutomu Hara, “Recent Developments in Liquid Crystal Spatial Light Modulation Elements”, Optics, Vol. 36, No. 3, pp. 122-128, 2007

[0007] Non-Patent Literature 3: Yoshitomo Isomae et al., "Alignment control of liquid crystals in a 1.0-mm-pitch spatial light modulator by lattice-shaped dielectric wall structure", J.Soc.Inf.Display 27, pp.251-258 (2019)

[0008] Non-patent literature 4: Y. Kurosaka et al., “Effects of non-lasing band in two-dimensional photonic-crystal lasers clarified using omnidirectional band structure”, Opt. Express 20, 21773-21783 (2012).

[0009] Non-patent literature 5: Y. Kurosaka et al., “Phase-modulating lasers toward on-chip integration”, Scientific Reports 6, 30138 (2016). Summary of the Invention

[0010] As a result of research addressing the aforementioned existing problems, the inventors discovered the following issue: Non-Patent Document 1 discloses an example of a device that displays an image stereoscopically by outputting two-dimensional optical images corresponding to each direction along a 360° circumference. However, in the device disclosed in Non-Patent Document 1, it is difficult to enlarge the holographic screen because it requires mechanically rotating the holographic screen at high speed. Therefore, there is a problem of difficulty in magnifying the stereoscopic image.

[0011] This disclosure was made to solve a problem, and its purpose is to provide an image output device having a structure for easily magnifying stereoscopic images.

[0012] An image output device according to one embodiment includes a spatial light modulator, an image illumination unit, and an addressing light illumination unit. The spatial light modulator has a main surface, a back surface opposite the main surface, and a plurality of pixels arranged in a two-dimensional manner along the main surface in the space between the main surface and the back surface. The spatial modulator reflects light illuminating the main surface and modulates the phase of the light at each of the plurality of pixels. The image illumination unit illuminates a two-dimensional optical image toward the main surface. The addressing light illumination unit illuminates addressing light including a diffraction grating pattern toward the back surface. Furthermore, each of the plurality of pixels of the spatial light modulator is configured such that the phase modulation amount changes according to the intensity of the addressing light illuminating from the back surface. The addressing light illumination unit is configured such that the direction of the diffraction grating pattern on the back surface dynamically changes. The image illumination unit illuminates a two-dimensional optical image on the main surface corresponding to the direction of the diffraction grating pattern. Attached Figure Description

[0013] Figure 1 This is a perspective view schematically showing the overall structure of the image output device 1A according to this embodiment.

[0014] Figure 2 This is a cross-sectional view of the image output device 1A.

[0015] Figure 3 This is a cross-sectional view of the spatial light modulator 3, showing the section intersecting the main surface 3a and the back surface 3b.

[0016] Figure 4 (a) is a magnified top view of a portion of partition wall 39a. Figure 4 (b) is a magnified perspective view of a portion of partition wall 39a, showing the structure near partition wall 39a upside down.

[0017] Figure 5 (a)~ Figure 5 (d) is a cross-sectional view showing the various steps in the fabrication method of the spatial light modulator 3.

[0018] Figure 6 (a)~ Figure 6 (d) is a cross-sectional view showing the various steps in the fabrication method of the spatial light modulator 3.

[0019] Figure 7 This is a top view of the light-emitting device 41 as viewed from the axial direction of the ring.

[0020] Figure 8 This is a front view showing the light-emitting surface 42a of a light-emitting part 42.

[0021] Figure 9 This is a conceptual diagram showing the shape of addressing light E2 illuminating the back side 3b of the spatial light modulator 3.

[0022] Figure 10 This is a conceptual diagram showing the shape of addressing light E2 illuminating the back side 3b of the spatial light modulator 3.

[0023] Figure 11 This is a conceptual diagram showing the shape of addressing light E2 illuminating the back side 3b of the spatial light modulator 3.

[0024] Figure 12 This is a conceptual diagram showing the shape of addressing light E2 illuminating the back side 3b of the spatial light modulator 3.

[0025] Figure 13 This is a diagram showing the periodic alternation of region P1, which is the phase modulation amount of 0 (rad), and region P2, which is the phase modulation amount of π (rad), in a diffraction grating.

[0026] Figure 14 This is a diagram showing wavefront B2 moving in the opposite direction to wavefront B1.

[0027] Figure 15 This diagram schematically illustrates a unit PU consisting of three regions P1 to P3, and in each of the multiple units PU, the region P1 is arranged in the order of phase modulation amount 0 (rad), the region P2 is arranged in the order of phase modulation amount 2π / 3 (rad), and the region P3 is arranged in the order of phase modulation amount 4π / 3 (rad).

[0028] Figure 16 (a) is a graph showing the relationship between the perimeter Λ and the diffraction angle θ (=0°~90°) when the period Λ of the diffraction grating is normalized to the wavelength λ (where m=1). Figure 16 (b) magnified view Figure 16 The diffraction angle θ = 5° to 30° in the graph of (a) and Figure 16 (c) magnified to show Figure 16 The diffraction angle θ = 30° to 90° in the diagram of (a).

[0029] Figure 17 (a) is a graph showing the relationship between the spacing L and the diffraction angle θ (=0°~70°) when the spacing L is normalized to wavelength λ (where m=1). Figure 17 (b) magnified view Figure 17 The portion of the graph in (a) with spacing L = 0 to 2λ.

[0030] Figure 18 (a) is a graph showing the relationship between the spacing L and the diffraction angle θ (=0°~70°) (where m=1) in the case of wavelength λ=532nm. Figure 18 (b) magnified view Figure 18The portion of the graph in (a) with a spacing L = 0 nm to 1000 nm.

[0031] Figure 19 To show in more detail Figure 15 The graph shows the relationship between the diffraction angle θ and the phase modulation amount of each region P1 to P3.

[0032] Figure 20 This is a diagram showing the wavefront B3 generated by the wave generated from region P2 at a certain moment and the wave generated from region P1 at the previous moment.

[0033] Figure 21 (a) is a graph showing the relationship between the spacing L and the diffraction angle θ that satisfies equation (2) in the case of, for example, a wavelength of 532 nm. Figure 21 (b) is shown in magnification. Figure 21 The graph of L to 2μm in (a) is a graph.

[0034] Figure 22 It is a graph that plots the correlation between the phase difference between adjacent regions and the value of m.

[0035] Figure 23 This shows that when the wavelength λ = 532 nm is given a diffraction angle θ in the design, the spacing L that satisfies equation (2) is obtained, and the diffraction angle θ is obtained by substituting the spacing L into equation (5). B The results are presented in a chart.

[0036] Figure 24 (a) is a graph showing the relationship between the spacing L and the diffraction angle θ that satisfies equation (2) at a wavelength of 467 nm. Figure 24 (b) is shown in magnification. Figure 24 The graph of L to 2μm in (a) is a graph.

[0037] Figure 25 It is a graph that plots the correlation between the phase difference between adjacent regions and the value of m.

[0038] Figure 26 This shows that when the wavelength λ = 467 nm is given a diffraction angle θ in the design, the spacing L that satisfies equation (2) is obtained, and the diffraction angle θ is obtained by substituting the spacing L into equation (5). B The results are presented in a chart.

[0039] Figure 27 (a) is a graph showing the relationship between the spacing L and the diffraction angle θ that satisfies equation (2) at a wavelength of 630 nm. Figure 27 (b) is shown in magnification. Figure 27 The graph of L to 2μm in (a) is a graph.

[0040] Figure 28 It is a graph that plots the correlation between the phase difference between adjacent regions and the value of m.

[0041] Figure 29 This shows that when the wavelength λ = 630 nm is given a diffraction angle θ in the design, the spacing L that satisfies equation (2) is obtained, and the diffraction angle θ is obtained by substituting the spacing L into equation (5). B The results are presented in a chart.

[0042] Figure 30 Figure (a) is a diagram showing an example of a suitable diffraction grating based on the research results. Figure 30 (b) is a locally magnified view. Figure 30 The diagram of (a).

[0043] Figure 31 It is a graph that conceptually illustrates the relationship between the phase modulation amount of the spatial light modulator 3 and the light intensity of the addressing light E2.

[0044] Figure 32 (a) is a diagram showing the light-shielding pattern 80 of the light-shielding film (or light-shielding plate). Figure 32 (b) and Figure 32 Figure (c) is an example of the planar shape of the shading area 81. Figure 32 (d) is a top view showing an example of a light-shielding film.

[0045] Figure 33 Figures (a) and (b) of 33 are diagrams conceptually illustrating the method for determining the phase modulation amount in each region constituting the diffraction grating.

[0046] Figure 34 Figures (a) and (b) of 34 are conceptual diagrams illustrating the method for determining the amount of phase modulation in each region constituting the diffraction grating.

[0047] Figure 35 (a) and Figure 35 (b) is a diagram showing the structure of the first modified example.

[0048] Figure 36 (a) is a side cross-sectional view showing the structure of the addressing light irradiation unit 4B as a second modified example. Figure 36 (b) is a top view of the light-emitting device 41 with addressing light illumination 4B and the optical component 44.

[0049] Figure 37 (a) is a side cross-sectional view showing the structure of the addressing light irradiation unit 4C as a third modified example. Figure 37 (b) is a top view of the light-emitting device 46 having an addressable light irradiation section 4C. Figure 37 (c) is along Figure 37(b) A cross-sectional view of the light-emitting device 46 of line II.

[0050] Figure 38 (a) is a top view showing another structure of the light-emitting device 46 as a third variation. Figure 38 (b) is along Figure 38 (a) Cross-sectional view of line II-II.

[0051] Figure 39 This diagram schematically illustrates the structure of the addressing light irradiation unit 4D, as a fourth variation.

[0052] Figure 40 (a) is a diagram schematically showing the structure of the addressing light irradiation unit 4E as a fifth variation. Figure 40 (b) is a top view of the light-emitting device 49 viewed from the axial direction of the ring.

[0053] Figure 41 of (a), Figure 41 (b) and Figure 41 (c) is a diagram schematically showing another structure of the fifth variation.

[0054] Figure 42 This is a schematic diagram showing the structure of the addressing light irradiation section 4F, which is another structure as a fifth variation.

[0055] Figure 43 (a) is a cross-sectional view showing the structure of the surface-emitting laser element array 50. Figure 43 (b) is an enlarged cross-sectional view showing the phase modulation layer 65A.

[0056] Figure 44 This is a top view of the phase modulation layer 65A.

[0057] Figure 45 This is a diagram showing the location of the centroid G of the region of differential refractive index on the XY plane.

[0058] Figure 46 It is used to illustrate the optical image obtained by imaging the output beam pattern of the surface-emitting laser element array 50 and the rotation angle distribution in the phase modulation layer 65A. A diagram showing the relationships between them.

[0059] Figure 47 It is used to explain the relationship between spherical coordinates (r, θ) and spherical coordinates (r, rot θ tilt A graph showing the transformation of coordinates (ξ, η, ζ) from the XYZ orthogonal coordinate system.

[0060] Figure 48 (a) and Figure 48(b) is a diagram of points of interest used to illustrate the calculations performed using a general discrete Fourier transform (or fast Fourier transform) when determining the configuration of each differential refractive index region 65b.

[0061] Figure 49 It conceptually illustrates the distribution of rotation angles. An example diagram.

[0062] Figure 50 This is a top view showing another example of a structure with a phase modulation layer for an S-iPM laser.

[0063] Figure 51 This is a diagram showing the positional relationship of the differential refractive index region 65b in the phase modulation layer 65B.

[0064] Figure 52 This is a top view showing the structure of a reflective dynamic metasurface (hereinafter referred to as metasurface) 7A, another example of a spatial light modulator.

[0065] Figure 53 It is along Figure 52 The cross-sectional view along line III-III shows the cross-sectional structure of the metasurface 7A.

[0066] Figure 54 This is a cross-sectional view of supersurface 7B, which is another structure of supersurface. Detailed Implementation

[0067] [Description of embodiments of this disclosure]

[0068] First, the contents of the embodiments of this disclosure will be described individually.

[0069] (1) As one embodiment, the image output device of this disclosure includes: a spatial light modulator, an image illumination unit, and an addressing light illumination unit. The spatial light modulator has a main surface, a back surface opposite to the main surface, and a plurality of pixels arranged in a two-dimensional manner along the main surface in the space between the main surface and the back surface. The spatial modulator reflects light illuminating the main surface and modulates the phase of the light in each of the plurality of pixels. The image illumination unit illuminates a two-dimensional optical image toward the main surface. The addressing light illumination unit illuminates addressing light including a diffraction grating pattern toward the back surface. Furthermore, each of the plurality of pixels of the spatial light modulator is configured such that the phase modulation amount changes according to the intensity of the addressing light illuminating from the back surface. The addressing light illumination unit is configured such that the direction of the diffraction grating pattern on the back surface changes dynamically. The image illumination unit illuminates a two-dimensional optical image on the main surface corresponding to the direction of the diffraction grating pattern.

[0070] In this image output device, the addressing light irradiation unit irradiates the back side of the spatial light modulator with addressing light containing a diffraction grating pattern. Since each pixel of the spatial light modulator has a structure that changes the phase modulation amount according to the intensity of the addressing light irradiating the back side of each pixel, the spatial light modulator imparts a phase pattern corresponding to the diffraction grating pattern to the light incident on the main surface. Therefore, the two-dimensional optical image irradiated by the image irradiation unit onto the main surface is deflected in a direction corresponding to the direction of the diffraction grating pattern. Furthermore, since the addressing light irradiation unit dynamically changes the direction of the diffraction grating pattern on the back side, the deflection direction of the two-dimensional optical image also dynamically changes. Moreover, since the image irradiation unit can irradiate the main surface with a two-dimensional optical image corresponding to the desired direction of the diffraction grating pattern, a stereoscopic image can be presented to the observer. Furthermore, according to this image output device, by dynamically changing the addressing light containing the diffraction grating pattern to output a stereoscopic image, it is possible to keep the spatial light modulator, which serves as a light deflection element, stationary while outputting a stereoscopic image. Therefore, compared with the device disclosed in Non-Patent Document 1, which mechanically rotates the holographic screen at high speed, the size of the spatial light modulator can be easily increased and the stereoscopic image magnified.

[0071] (2) As one aspect of this disclosure, the addressing light irradiation unit can also rotate the diffraction grating pattern on the aforementioned back surface. In this case, a three-dimensional image can be presented in the entire 360° circumferential direction.

[0072] (3) As one embodiment of this disclosure, the spatial light modulator may also include: a light-reflecting layer, a liquid crystal layer, a light-transmitting first electrode layer, an impedance-changing layer, and a light-transmitting second electrode layer. The light-reflecting layer is disposed between the main surface and the back surface. The liquid crystal layer is disposed between the light-reflecting layer and the main surface. The light-transmitting first electrode layer is disposed between the liquid crystal layer and the main surface. The impedance-changing layer is disposed between the light-reflecting layer and the back surface. This impedance-changing layer reflects the impedance distribution according to the intensity distribution of the addressing light. The light-transmitting second electrode layer is disposed between the impedance-changing layer and the back surface. Furthermore, the liquid crystal layer has multiple partition walls that divide the liquid crystal into regions corresponding to multiple pixels respectively. In this case, when the addressing light is irradiated onto the back surface of the spatial light modulator, the impedance distribution of the impedance-changing layer becomes a distribution corresponding to the intensity distribution of the addressing light. When a voltage is applied between the first electrode layer and the second electrode layer, a strong electric field is applied to the liquid crystal layer at pixels with low impedance in the impedance-changing layer. Conversely, a weak electric field is applied to the liquid crystal layer at pixels with high impedance in the impedance-changing layer, or no electric field is applied at all. Therefore, according to this image output device, in each pixel of the spatial light modulator, a structure can be implemented that changes the phase modulation amount according to the intensity of the addressing light illuminating the back side of each pixel. Furthermore, by having partition walls in the liquid crystal layer that divide the liquid crystal into regions corresponding to each pixel, the interaction between the liquid crystals between pixels can be reduced, and the phase pattern corresponding to the diffraction grating pattern can be made clearer.

[0073] (4) As one embodiment of the present invention, a plurality of partition walls may be arranged in a two-dimensional configuration along a first direction of the main surface and a second direction orthogonal to the first direction on the main surface, wherein the spacing between adjacent partition walls arranged along the second direction is greater than the spacing between adjacent partition walls arranged along the first direction. In this case, since the orientation of the liquid crystal is easy to align, the light transmittance / non-transmittance of the liquid crystal for a specific polarization direction can be effectively utilized.

[0074] (5) As one aspect of this disclosure, the spacing between adjacent partition walls arranged along the second direction is more than twice the spacing between adjacent partition walls arranged along the first direction. According to the inventors, in this case, since the orientation of the liquid crystal is particularly easy to align, the light transmittance / non-transmittance of the liquid crystal for a specific polarized light direction can be effectively utilized.

[0075] (6) As one embodiment of the present invention, a plurality of partition walls may be arranged in a two-dimensional configuration along both a first direction on the main surface and a second direction orthogonal to the first direction on the main surface, wherein the spacing between adjacent partition walls arranged along the first direction and the spacing between adjacent partition walls arranged along the second direction are both 5 μm or less. By constructing the partition walls with small intervals as described above, the pixel size of the spatial light modulator can be reduced, thereby shortening the period of the diffraction grating. Therefore, the diffraction angle of the two-dimensional optical image of the spatial light modulator can be increased, and the output direction of the stereoscopic image can be made close to the plane containing the main surface of the spatial light modulator, thereby providing a practical stereoscopic image to an observer present around the spatial light modulator.

[0076] (7) As an aspect of this disclosure, the impedance-changing layer may also comprise at least one of hydrogenated amorphous silicon, GaN-based compounds, InP-based compounds, and GaAs-based compounds. The impedance of these materials changes upon receiving light. Therefore, in this case, an impedance-changing layer that reflects the impedance distribution according to the intensity distribution of the addressing light can be appropriately realized.

[0077] (8) As one aspect of the present invention, the spatial light modulator in the above-described image output device may include: a stacked structure, a first metal film, a second metal film, an impedance variation layer, and a light-transmitting electrode layer. The stacked structure includes: a first surface, a second surface opposite to the first surface, a transparent conductive layer disposed between the first surface and the second surface, and a dielectric layer disposed between the first surface and the second surface. A two-dimensional optical image is input to the first surface of the stacked structure. The first metal film is disposed on the first surface of the stacked structure. The second metal film is disposed on the second surface of the stacked structure. The second metal film reflects the two-dimensional optical image input to the stacked structure toward the first surface. The impedance variation layer is disposed on the opposite side of the stacked structure relative to the second metal film. The impedance variation layer reflects the impedance distribution according to the intensity distribution of the addressing light. The light-transmitting electrode layer is disposed on the opposite side of the second metal film relative to the impedance variation layer. Alternatively, either the first metal film or the second metal film may correspond to a plurality of pixels and be composed of a plurality of mutually separated partial metal films. In this structure, viewed from the stacking direction, a portion of the stacked structure is exposed between the multiple partial metal films constituting the first metal film.

[0078] When addressing light is shone onto the back of the spatial light modulator, the impedance distribution of the impedance variation layer corresponds to the intensity distribution of the addressing light. When a voltage is applied between the first metal film and the electrode layer, a strong electric field is applied between the first and second metal films to pixels with low impedance in the impedance variation layer. Conversely, a weak electric field, or no electric field at all, is applied between the first and second metal films to pixels with high impedance in the impedance variation layer. Furthermore, in this image output device, the stacked structure comprises a pair of portions. When viewed from the stacking direction, these portions are respectively positioned at a pair of locations sandwiching the first metal film and are exposed from the first metal film. Light input to one of these portions is guided between the first and second metal films and output externally from the other direction of the pair of portions. When the width of the first metal film and the thickness of the stacked structure are sufficiently small compared to the wavelength of light, when an electric field is applied between the first and second metal films, induced currents in opposite directions, called gap surface plasmon modes, are generated in both the first and second metal films, and strong magnetic resonance (plasma resonance) is generated within the stacked structure. This magnetic resonance allows modulation of the phase of light passing between the first and second metal films. Here, when an electric field is applied between the first and second metal films, the electron density near the interface between the transparent conductive layer and the dielectric layer contained in the stacked structure increases. As a result, the portion near this interface of the transparent conductive layer is effectively metallized, and the effective refractive index of the stacked structure changes significantly. Since the modulation amount in the aforementioned phase modulation depends on the effective refractive index of the stacked structure, the effective refractive index can be controlled by changing the electric field between the first and second metal films, thereby controlling the phase of the output light. Therefore, according to this image output device, a structure in each pixel of the spatial light modulator can be implemented that changes the amount of phase modulation based on the intensity of the addressing light illuminating the back side of each pixel.

[0079] (9) As one embodiment of this disclosure, the addressing light irradiation unit may also have a light-emitting unit and a driving unit. The light-emitting unit outputs addressing light containing a diffraction grating pattern. The driving unit dynamically changes the attitude angle around the optical axis of the light-emitting unit. In this case, the addressing light irradiation unit that dynamically changes the direction of the diffraction grating pattern on the back side can be appropriately implemented.

[0080] (10) As one embodiment of this disclosure, the addressing light illumination unit may include multiple light-emitting units and an optical system. The multiple light-emitting units are arranged circumferentially and output addressing light containing a diffraction grating pattern. The optical system optically couples the multiple light-emitting units to the back surface. Additionally, addressing light from a portion of the light-emitting units selected from the multiple light-emitting units that corresponds to the direction of the diffraction grating pattern (one or more light-emitting units) is input to the back surface. In this case, the mechanical drive unit can be eliminated, thereby improving reliability. Furthermore, by including a metalen in the optical system, a large-area and thin optical system can be realized, and addressing light with a relatively large range can be irradiated onto the back surface of the spatial light modulator. As one embodiment of this disclosure, the optical system may include a metalen.

[0081] (11) As one aspect of this disclosure, the addressing light irradiation unit may have a light-emitting unit arranged circumferentially. This light-emitting unit outputs addressing light comprising a diffraction grating pattern in which the radial direction of the circumference is set as the periodic direction. Alternatively, the light-emitting unit may be a plurality of element electrodes arranged circumferentially along the circumference. The element electrode among the plurality of element electrodes corresponding to the direction of the diffraction grating pattern selectively emits the addressing light. In this case, an addressing light irradiation unit that dynamically changes the direction of the diffraction grating pattern on the back side can be appropriately implemented.

[0082] (12) As one aspect of this disclosure, the light-emitting part may include a plurality of light-emitting regions arranged based on a diffraction grating pattern. Alternatively, as one aspect of this disclosure, the light-emitting part may include a surface-emitting laser element having an active layer and a phase modulation layer. The phase modulation layer may also include a base layer and differential refractive index regions having a refractive index different from that of the base layer. The plurality of differential refractive index regions are distributed in a two-dimensional manner on a plane perpendicular to the thickness direction of the phase modulation layer. Furthermore, a virtual square lattice may be set on the surface of the phase modulation layer, and the centroid of each of the plurality of differential refractive index regions may be set to a first state or a second state. Moreover, the first state is defined by the state in which the centroids of each of the plurality of differential refractive index regions are separately arranged from corresponding lattice points in the virtual square lattice, and the rotation angle around the corresponding lattice point is individually set for each of the plurality of differential refractive index regions. The second state is defined by aligning the centroids of each of the multiple differential refractive index regions along a straight line tilted towards the square grid, with each centroid of a different refractive index region having a corresponding grid point within the grid. The distance between the centroid of each differential refractive index region and its corresponding grid point is individually set. Either of these first or second states can be used to appropriately implement a light-emitting unit that outputs addressable light containing a diffraction grating pattern.

[0083] (13) As one embodiment of this disclosure, the light-emitting part may have a photonic crystal surface-emitting laser element and a periodic structure. The photonic crystal surface-emitting laser element has an active layer and a photonic crystal layer. The periodic structure is disposed on the light-emitting surface of the photonic crystal surface-emitting laser element. In this periodic structure, openings and light-blocking portions are periodically provided according to a diffraction grating pattern. In this case, a light-emitting part that outputs addressing light containing a diffraction grating pattern can be appropriately realized.

[0084] (14) As one embodiment of this disclosure, the addressing light irradiation unit may include a laser source, a branching section, and an interference optical system. The branching section branches the laser output from the laser source. The interference optical system causes the laser from one branched by the branching section to interfere with the laser from the other branch, generating interference fringes. Furthermore, the interference optical system includes a position-changing section that dynamically changes the relative positional relationship between the lasers from one branch and the laser from the other branch during interference. Alternatively, the interference fringes may be used as a diffraction grating pattern. As described above, the interference fringes can be used as a diffraction grating pattern. Furthermore, by dynamically changing the relative positional relationship between the lasers from one branch and the laser from the other branch during interference, the direction of the interference fringes, i.e., the direction of the diffraction grating pattern, can be dynamically changed. Therefore, in this case, the addressing light irradiation unit can be appropriately implemented.

[0085] (15) As one aspect of this disclosure, the diffraction grating pattern may have a structure in which the light intensity changes periodically along a certain direction, with the light intensity increasing or decreasing monotonically in each period. Furthermore, the number of regions with different light intensities in each period is three or more. In this case, the bias in the direction opposite to the desired bias direction of the two-dimensional optical image can be reduced, and a more clearly output stereoscopic image can be achieved.

[0086] (16) As an aspect of this disclosure, the image output device may also include a filter disposed between the image illumination unit and the spatial light modulator. This filter reduces the intensity of at least a portion of the wavelength components other than visible light contained in the two-dimensional optical image. This reduces the extent to which the light from the two-dimensional optical image from the image illumination unit affects the phase modulation amount of the spatial light modulator.

[0087] The aspects listed above in the "Description of Embodiments of this Disclosure" section are applicable to all remaining methods or all combinations of these remaining methods.

[0088] [Details of the embodiments of the present invention]

[0089] The specific structure of the image output device involved in this disclosure will now be described in detail with reference to the accompanying drawings. Furthermore, the invention is not limited to these examples, but is indicated by the scope of the claims and is intended to include the meaning equivalent to the scope of the claims and all modifications within that scope. Additionally, in the description of the drawings, the same elements are given the same reference numerals, and repeated descriptions are omitted.

[0090] In the following explanation, "transmittance" means that more than 50 percent of the wavelength of light that is the object of transmission is transmitted.

[0091] (This implementation method)

[0092] Figure 1 This is a perspective view schematically showing the overall structure of the image output device 1A according to this embodiment. Figure 2 This is a cross-sectional view of the image output device 1A. The image output device 1A is a device that simulates displaying a stereoscopic (three-dimensional) image to an observer A located to the side of the image output device 1A. Figure 1 and Figure 2 As shown, the image output device 1A includes a high-speed projector 2A, a spatial light modulator 3, and an addressing light irradiation unit 4A. The spatial light modulator 3 is a plate-shaped device having a main surface (upper surface) 3a and a back surface (lower surface) 3b located opposite to the main surface 3a. The main surface 3a and the back surface 3b are flat and parallel to each other, and in one example, their normal directions are along the vertical direction. The high-speed projector 2A is positioned above the spatial light modulator 3, opposite to the main surface 3a. The addressing light irradiation unit 4A is positioned below the spatial light modulator 3, opposite to the back surface 3b, and includes a rotation drive unit 400 that rotates a diffraction grating pattern in the direction indicated by arrow S relative to the axis AX showing the center of the spatial modulator 3.

[0093] The high-speed projector 2A is an example of the image illumination unit in this embodiment, and it illuminates the main surface 3a of the spatial light modulator 3 with light E1 containing a two-dimensional optical image. The incident direction of the light E1 relative to the main surface 3a is the same as the normal direction of the main surface 3a. The high-speed projector 2A can output light E1 of a single wavelength or light E1 containing multiple wavelength components. The single or multiple wavelength components of light E1 are contained in the visible light domain. In one example, the multiple wavelength components are a green component, a blue component, and a red component. The high-speed projector 2A can preferably be appropriately configured as a DLP (Digital Light Processing) projector, for example, using a DMD (Digital Micromirror Device). The frame rate of the high-speed projector 2A is, for example, more than 1k frames per second and less than 100k frames per second. This frame rate can also be set to a suitable value according to the rotation speed of the diffraction grating pattern output from the addressing light illumination unit 4A described later.

[0094] like Figure 2 As shown, a filter 15 and a lens 16 are arranged in the optical path between the high-speed projector 2A and the spatial light modulator 3. The filter 15 is a wavelength filter that reduces (or removes) the intensity of at least a portion of the wavelength components of light E1, excluding visible light. In one example, the filter 15 is a bandpass filter that reduces (or removes) the intensity of all wavelength components of light E1, excluding visible light. Furthermore, the filter 15 can also reduce (or remove) wavelengths other than any wavelength domain containing the wavelength components of light E1. In this case, the visible domain may also include other wavelength domains. The lens 16 is an imaging lens that images the image of light E1 onto the retina of the eye Aa of the observer A. Furthermore, in Figure 2 In the example shown, a filter 15 is disposed between the high-speed projector 2A and the lens 16, or the lens 16 can be disposed between the high-speed projector 2A and the filter 15.

[0095] The spatial light modulator 3 reflects light E1 containing a two-dimensional optical image illuminating the main surface 3a, and modulates the phase of each of the modulated light E1 for a plurality of pixels arranged in a two-dimensional manner. Each pixel of the spatial light modulator 3 has a structure that changes the phase modulation amount according to the intensity of each pixel of the addressing light E2 illuminating from the back surface 3b. Figure 3 This is a cross-sectional view of the spatial light modulator 3, showing the section intersecting the main surface 3a and the back surface 3b. (See diagram below.) Figure 3 As shown, the spatial light modulator 3 includes: a transparent substrate 31, a transparent electrode layer 32, an impedance change layer 33, a dielectric reflector 34, a liquid crystal alignment film 35, a liquid crystal layer 36, a transparent electrode layer 37, and a transparent substrate 38.

[0096] The transparent substrate 31 is a plate-shaped component with light transmittance. Here, "light transmittance" refers to the ability to transmit light through the addressing light E2 (see reference 1) as described later. Figure 2 The transparent substrate 31 is a glass substrate. The transparent substrate 31 includes a main surface 31a and a back surface 31b that are parallel to each other and face opposite directions. The main surface 31a and the back surface 31b are flat and smooth surfaces. The back surface 31b corresponds to the back surface 3b of the spatial light modulator 3. The thickness of the transparent substrate 31 is, for example, more than 20 μm and less than 1 mm.

[0097] The transparent electrode layer 32 is an example of the second electrode layer in this embodiment, located between the impedance variation layer 33 and the back surface 3b. Figure 3 In the example shown, the transparent electrode layer 32 is in contact with the main surface 31a of the transparent substrate 31. The transparent electrode layer 32, like the transparent substrate 31, has light transmittance. That is, the transparent electrode layer 32 allows the addressing light E2 (described later) to pass through. Figure 2 The transparent electrode layer 32 is made of at least one of, for example, indium tin oxide (ITO) or zinc oxide-based conductive materials (aluminum-doped zinc oxide (AZO) or gallium-doped zinc oxide (GZO)). The thickness of the transparent electrode layer 32 is, for example, more than 1 nm and less than 1 μm. The transparent electrode layer 32 divides each pixel, and the transparent electrode layers 32 of each pixel are separated from each other by gaps (slits) GA.

[0098] The impedance variation layer 33 is a semiconductor layer located between the dielectric reflector 34 and the back surface 3b. Figure 3 In the example shown, the impedance changing layer 33 is located between the dielectric reflector 34 and the transparent electrode layer 32. The impedance changing layer 33 adjusts according to the addressing light E2 (reference). Figure 2The impedance distribution is reflected by the intensity distribution of light. Specifically, the impedance of the material constituting the impedance changing layer 33 changes monotonically according to the light intensity when light is received. Examples of such materials include hydrogenated amorphous silicon, GaN-based compounds, InP-based compounds, and GaAs-based compounds. Therefore, the impedance changing layer 33 of this embodiment can be composed of at least one of hydrogenated amorphous silicon, GaN-based compounds (e.g., i-type GaN), InP-based compounds (e.g., i-type InP), and GaAs-based compounds (e.g., i-type GaAs). Furthermore, the constitutive material of the impedance changing layer 33 is not limited to these, and can also be, for example, a semiconductor material with photoconductivity. The wavelength of the address light E2 is, for example, 400 nm or more and 2 μm or less. If the address light E2 is infrared light, it is suitable because even if the address light E2 leaks out of the main surface 3a, it is invisible to the observer A and will not become noise light. The thickness of the impedance changing layer 33 is, for example, 10 nm or more and 20 μm or less. The impedance change layer 33 divides each pixel, and the impedance change layers 33 of each pixel are separated from each other by gaps GA.

[0099] The dielectric reflector 34 is an example of a light-reflecting layer in this embodiment, reflecting light E1 incident on the main surface 3a. The dielectric reflector 34 is located between the main surface 3a and the back surface 3b, and as a specific example, is located between the impedance variation layer 33 and the liquid crystal layer 36. Figure 3 In the example shown, the dielectric mirror 34 is connected to the impedance variation layer 33. The dielectric mirror 34 has a structure in which high-refractive-index dielectric layers and low-refractive-index dielectric layers with low refractive indices relative to the high-refractive-index dielectric layers are alternately stacked. The high-refractive-index dielectric layers include at least one of, for example, Ta2O5, TiO2, Nb2O5, SiN, Al2O3, and HfO2. The low-refractive-index dielectric layers include at least one of, for example, SiO2 and MgF2. The dielectric mirror 34 divides each pixel, and the dielectric mirrors 34 of each pixel are separated from each other by a gap GA.

[0100] The liquid crystal alignment film 35 is of parallel alignment type and is disposed on the dielectric reflector 34, and in one example, is in contact with the dielectric reflector 34. The liquid crystal alignment film 35 can be constructed by including, for example, a polycarbonate film and an alignment film (e.g., JSR's AL-1254) disposed on the polycarbonate film. The liquid crystal alignment film 35 divides each pixel, and the liquid crystal alignment films 35 of each pixel are separated from each other by a gap GA.

[0101] The liquid crystal layer 36 is located between the dielectric reflector 34 and the main surface 3a, and, as a specific example, between the dielectric reflector 34 and the transparent electrode layer 37. In one example, the liquid crystal layer 36 comprises nematic liquid crystal 36a. Furthermore, the liquid crystal layer 36 has partition walls 39a that divide the nematic liquid crystal 36a into regions corresponding to pixels. The partition walls 39a are, for example, made of resin. Alternatively, the partition walls 39a may also be made of semiconductor materials such as Si, or inorganic materials such as SiO2 or SiN. Figure 4 (a) is a top view of a partially enlarged partition wall 39a. Figure 4 (b) is a magnified perspective view of the partition wall 39a, and the structure near the partition wall 39a is shown upside down. Figure 4 As shown in (a) and (b) of 4, the partition wall 39a of this embodiment has a lattice-like planar shape, dividing the liquid crystal layer 36 into rectangular regions when viewed from the thickness direction. Furthermore, not limited to this example, the partition wall 39a may also divide the liquid crystal layer into square regions. Additionally, the partition wall 39a is integrally formed with the layer 39b disposed on the liquid crystal layer 36. The partition wall 39a and the liquid crystal alignment film 35 are bonded to each other via a spacer 301 surrounding the liquid crystal layer 36. The spacer 301 is a resin adhesive containing dispersed beads. The diameter of the dispersed beads is greater than the height h of the partition wall 39a, for example, a diameter of several μm. Thus, gaps in the liquid crystal can be formed between the liquid crystal alignment film 35 and the partition wall 39a. The height h of the partition wall 39a is, for example, 1 μm. The width w of the partition wall 39a is, for example, 0.17 μm or more and 0.2 μm or less.

[0102] like Figure 4 As shown in (a), the partition wall 39a includes a portion extending along a first direction D1 of the main surface 3a, and a portion extending along a second direction D2 that intersects (e.g., is orthogonal) the first direction D1 of the main surface 3a. The spacing (center spacing) d1 between the portions extending along the second direction D2 is greater than the spacing d2 between the portions extending along the first direction D1. Therefore, the planar shape of a space (pixel) divided by the partition wall 39a is a rectangle with the first direction D1 as its long side. The spacing d1 can also be more than twice the spacing d2; in one embodiment, the spacing d1 is twice the spacing d2. Alternatively, both spacing d1 and d2 can be less than 5 μm; in one embodiment, the spacing d1 is 1 μm and the spacing d2 is 0.5 μm.

[0103] Refer again Figure 3 The transparent electrode layer 37 is an example of the first electrode layer in this embodiment, located between the liquid crystal layer 36 and the main surface 3a. Figure 3In the example shown, the transparent electrode layer 37 is in contact with the surface of layer 39b, which is integrated with partition wall 39a, located on the opposite side of partition wall 39a. The transparent electrode layer 37 is light-transmitting. Here, "light transmittance" refers to the ability to transmit light E1 (refer to...) containing a two-dimensional optical image emitted from the high-speed projector 2A. Figure 2 Transmittance properties. In one example, the transparent electrode layer 37 allows transmission of wavelengths including the visible light domain. The constituent material of the transparent electrode layer 37 includes at least one of, for example, ITO, zinc oxide-based conductive materials (AZO, GZO). The thickness of the transparent electrode layer 37 is, for example, more than 1 nm and less than 1 μm. Unlike the transparent electrode layer 32, the transparent electrode layer 37 is not divided for each pixel, but is integrally disposed across multiple pixels.

[0104] The transparent substrate 38 is a plate-shaped component that, like the transparent electrode layer 37, has light transmittance. That is, the transparent substrate 38 allows light E1 (referring to the image emitted from the high-speed projector 2A) to pass through. Figure 2 Transparency is achieved through the transparent substrate 38. In one example, the transparent substrate 38 is a glass substrate. The transparent substrate 38 includes a main surface 38a and a back surface 38b that are parallel to each other and face opposite directions. The main surface 38a and the back surface 38b are flat and smooth surfaces. The main surface 38a coincides with the main surface 3a of the spatial light modulator 3. The back surface 38b is opposite to, for example, in contact with, the transparent electrode layer 37. The thickness of the transparent substrate 38 is, for example, more than 20 μm and less than 1 mm.

[0105] The operation of the spatial light modulator 3 is as follows. First, an AC voltage source 11 is connected between the transparent electrode layer 32 and the transparent electrode layer 37 (see reference). Figure 2 An alternating current voltage is applied under the condition that the addressing light E2 is 3 volts, for example, and the frequency is in the range of 10 Hz to 100 Hz. When the addressing light E2 shines on the back side 3b, the addressing light E2 reaches the impedance changing layer 33 and imparts an impedance distribution to the impedance changing layer 33. That is, in pixels with low light intensity of the addressing light E2, the impedance of the impedance changing layer 33 remains high, and in pixels with high light intensity of the addressing light E2, the impedance of the impedance changing layer 33 decreases. Therefore, the impedance distribution of the impedance changing layer 33 corresponds to the intensity distribution of the addressing light E2. In pixels where the impedance of the impedance changing layer 33 decreases, the voltage applied to the liquid crystal layer 36 increases, and a strong electric field is applied to the liquid crystal layer 36. On the other hand, in pixels where the impedance of the impedance changing layer 33 remains high, the impedance of the impedance changing layer 33 is greater than the impedance of the liquid crystal layer 36, so the voltage applied to the liquid crystal layer 36 is low, and a weak electric field (or no electric field is applied at all) is applied to the liquid crystal layer 36. Furthermore, the addressing light E2 was blocked by the dielectric mirror 34 and did not reach the liquid crystal layer 36.

[0106] On the main surface 3a, light E1 containing a two-dimensional optical image is irradiated from the high-speed projector 2A. After passing through the transparent substrate 38, the transparent electrode layer 37, and the liquid crystal layer 36, light E1 is reflected by the dielectric mirror 34 and then passes through the liquid crystal layer 36, the transparent electrode layer 37, and the transparent substrate 38 again, exiting from the main surface 3a towards the outside of the spatial light modulator 3. In the liquid crystal layer 36, when an electric field is applied, the liquid crystal molecules of the nematic liquid crystal 36a tilt. The tilt of the liquid crystal molecules depends on the magnitude of the applied electric field. The more tilted the liquid crystal molecules are, the smaller the equivalent refractive index of the nematic liquid crystal 36a relative to light E1 becomes, and the phase of light E1 advances in the nematic liquid crystal 36a. Therefore, light E1 is given a phase distribution corresponding to the light intensity distribution of the addressing light E2. In the spatial light modulator 3, the response time required for π (rad) phase modulation is, for example, about 30 milliseconds, in which case a pattern change of 30 frames per second can be achieved.

[0107] Here, an example of the fabrication method for the spatial light modulator 3 will be explained. Figure 5 (a)~ Figure 5 (d) and Figure 6 (a)~ Figure 6 (d) is a cross-sectional view showing the various steps in the fabrication method of the spatial light modulator 3. First, as... Figure 5 As shown in (a), a transparent substrate 38 is prepared, and a transparent electrode layer 37 is formed on one surface of the transparent substrate 38. The transparent electrode layer 37 is formed by, for example, vacuum evaporation or sputtering. Next, as... Figure 5 As shown in (b), an ultraviolet-curable resin 39 for the partition wall 39a is coated on the surface of the transparent electrode layer 37 opposite to the transparent substrate 38. Then, as... Figure 5 As shown in (c), a mold 51 having grid-like grooves corresponding to the partition walls 39a is pressed onto the UV-curable resin 39 (nano-imprinting), its state is maintained, and UV light is irradiated onto the UV-curable resin 39 to cure it. Then, the mold 51 is removed. Thus, as Figure 5 As shown in (d), partition wall 39a and layer 39b are formed.

[0108] In addition, such as Figure 6 As shown in (a), a transparent substrate 31 is prepared, and a transparent electrode layer 32 is formed on one surface of the transparent substrate 31. The transparent electrode layer 32 is formed by, for example, vacuum evaporation or sputtering. Next, an impedance variation layer 33 is formed on the transparent electrode layer 32. The impedance variation layer 33 is formed by, for example, vacuum evaporation or sputtering. Then, as... Figure 6As shown in (b), a dielectric reflector 34 is formed on the impedance variation layer 33. That is, the dielectric reflector 34 is formed by alternately stacking a high-refractive-index dielectric layer and a low-refractive-index dielectric layer with a relatively low refractive index relative to the high-refractive-index dielectric layer. The high-refractive-index dielectric layer and the low-refractive-index dielectric layer are formed by, for example, vacuum evaporation or sputtering. Then, as... Figure 6 As shown in (c), a liquid crystal alignment film 35 is disposed on the dielectric reflector 34. Specifically, a polycarbonate film and an alignment film are stacked.

[0109] Subsequently, an adhesive containing dispersion beads is applied around the area where the liquid crystal on the liquid crystal alignment film 35 is filled. Figure 5 The partition wall 39a shown in (d) is... Figure 6 The liquid crystal alignment films 35 shown in (c) are bonded together. Figure 6 (d) At this time, the diameter of the dispersed beads is made larger than the height of the partition wall 39a, and a gap is provided between the partition wall 39a and the liquid crystal alignment film 35 to allow the nematic liquid crystal 36a to pass through. Furthermore, no adhesive is applied to the opening for liquid crystal filling. When the adhesive cures, the entire assembly is depressurized. Then, after injecting the nematic liquid crystal 36a from the opening for liquid crystal filling, the opening is sealed by applying adhesive. Thus, the spatial light modulator 3 is completed.

[0110] Refer again Figure 2 The addressing light irradiation unit 4A irradiates the back surface 3b of the spatial light modulator 3 with addressing light E2 containing a diffraction grating pattern. The addressing light irradiation unit 4A in this embodiment includes: an annular light-emitting device 41, an optical system 43 disposed inside the light-emitting device 41, and a rotation drive unit 400. Figure 7 This is a top view of the light-emitting device 41 as seen from the axial direction of the ring. (Example) Figure 7 As shown, the light-emitting device 41 includes a plurality of light-emitting portions 42 arranged based on a diffraction grating pattern. The plurality of light-emitting portions 42 are arranged circumferentially with their light-emitting surfaces 42a facing inward. Figure 8 This is a front view showing the light-emitting surface 42a of a light-emitting part 42. (See attached image.) Figure 8 As shown, each light-emitting unit 42 has light-emitting regions 42b and 42c arranged periodically and alternately in the vertical direction on the light-emitting surface 42a, based on a diffraction grating pattern. By having such light-emitting regions 42b and 42c, each light-emitting unit 42 can output addressing light E2 that includes the diffraction grating pattern described later in the near-field image. The light-emitting regions 42b and 42c can be formed by providing a periodic structure on the light-emitting surface of a surface-emitting semiconductor light-emitting element, such as a light-emitting diode or a surface-emitting laser, which periodically has openings and light-blocking portions according to a diffraction grating (for example, see the description below). Figure 38Figures (a) and (38b) can be used to construct the laser appropriately. The surface-emitting laser can also be a vertical-cavity surface-emitting laser (VCSEL), a photonic crystal surface-emitting laser (PCSEL) with an active layer and a photonic crystal layer, or an S-iPM laser (described later).

[0111] like Figure 2 As shown, the optical system 43 optically couples multiple light-emitting units 42 to the back surface 3b of the spatial light modulator 3. Furthermore, the optical system 43 deflects the addressing light E2 emitted from the light-emitting regions 42b and 42c of each light-emitting unit 42 toward the back surface 3b of the spatial light modulator 3. The optical system 43 is in the shape of a ring concentric with the light-emitting device 41. The shape of the optical system 43 in a cross-section including the central axis of the ring may include, for example, an off-axis convex lens. Alternatively, the shape of the optical system 43 in a cross-section including the central axis of the ring may also include a superlens. When the optical system 43 includes a superlens, the radial thickness of the optical system 43 can be reduced, making it suitable for dense configurations. Thus, in cases where adjacent lenses with large radii of curvature are in contact with each other, the convex lenses can be replaced with superlenses that function as flat lenses, and the deflection angle can be larger. Furthermore, the shape of the optical system 43 is not limited to these; various other shapes can be adopted if they allow the addressing light E2 to be deflected toward the back surface 3b.

[0112] Figures 9-12 This is a conceptual illustration of the shape of the addressing light E2 irradiated on the back surface 3b of the spatial light modulator 3. In these diagrams, the intensity distribution of the addressing light E2 is represented by the shades of color. Darker areas have lower light intensity, and lighter areas have higher light intensity. The addressing light E2 in this embodiment includes a region E2a with low (or essentially zero) light intensity, a region E2b with slightly higher light intensity, and a region E2c with high light intensity. These three regions E2a to E2c are arranged in a repeating pattern to form a diffraction grating. In other words, the diffraction grating pattern has a structure in which the light intensity changes periodically along a certain direction. Within each period, the light intensity gradually (i.e., monotonically) increases or decreases, and the number of regions with different light intensities within each period is 3 or more (in...). Figures 9-12 Example 3 is shown. Figure 9 As shown, the arrangement period of regions E2a to E2c is consistent with or greater than three times the pixel spacing along the long side of each pixel 30. Furthermore, as... Figures 9-12 As shown, the orientation of the diffraction grating pattern on the back surface 3b (the diffraction grating pattern contained in the addressing light E2 illuminating the back surface 3b) is, for example, through... Figure 1 and Figure 2 The rotation drive unit 400 of the addressing light irradiation unit 4A shown can be dynamically changed. For example, the direction of the diffraction grating pattern on the back surface 3b can be rotated around the center of the back surface 3b (with the central axis AX of the spatial modulator 3 as the center and the direction indicated by arrow S). Such a change in the direction of the diffraction grating pattern can be appropriately achieved by outputting the addressing light E2 from a portion of the light-emitting units 42 selected from the plurality of light-emitting units 42 that corresponds to the desired direction of the diffraction grating pattern. The rotation speed of the diffraction grating pattern is, for example, between 10 rpm and 10,000 rpm, and in one example, 3,600 rpm.

[0113] The effects obtained by the image output device 1A of this embodiment having the above structure will be explained. In the image output device 1A, the addressing light irradiation unit 4A irradiates the back surface 3b of the spatial light modulator 3 with addressing light E2 containing a diffraction grating pattern. Since each pixel 30 of the spatial light modulator 3 has a structure that changes the phase modulation amount according to the intensity of the addressing light E2 irradiating the back surface 3b of each pixel 30, the spatial light modulator 3 imparts a phase pattern corresponding to the diffraction grating pattern to the light E1 incident on the main surface 3a. Therefore, the two-dimensional optical image irradiated onto the main surface 3a by the high-speed projector 2A is deflected and output in a direction corresponding to the direction of the diffraction grating pattern when reflected by the spatial light modulator 3. In addition, since the addressing light irradiation unit 4A (rotation drive unit 400) dynamically changes the direction of the diffraction grating pattern on the back surface 3b, the deflection direction of the two-dimensional optical image also dynamically changes. When the high-speed projector 2A projects a two-dimensional optical image corresponding to the direction of the diffraction grating pattern onto the main surface 3a, a stereoscopic image can be presented to the observer A. Furthermore, according to this image output device 1A, since a stereoscopic image is output by dynamically changing the addressing light E2 containing the diffraction grating pattern, the spatial light modulator 3, which serves as a light deflection element, can be kept stationary while still outputting a stereoscopic image. Therefore, compared to the device disclosed in Non-Patent Document 1, which mechanically rotates the holographic screen at high speed, the size of the spatial light modulator 3 can be easily increased and the stereoscopic image magnified.

[0114] As in this embodiment, the addressing light irradiation unit 4A can also rotate the diffraction grating pattern on the back surface 3b of the spatial light modulator 3. In this case, a three-dimensional image can be presented in the entire 360° circumferential direction. Furthermore, the dynamic change in the orientation of the diffraction grating pattern is not limited to the rotation of the diffraction grating pattern, or it can also be a rotation operation within a limited angular range.

[0115] As in this embodiment, the spatial light modulator 3 may also include: a dielectric mirror 34 located between the main surface 3a and the back surface 3b; a liquid crystal layer 36 located between the dielectric mirror 34 and the main surface 3a; a transparent electrode layer 37 located between the liquid crystal layer 36 and the main surface 3a; an impedance changing layer 33 located between the dielectric mirror 34 and the back surface 3b, which reflects the impedance distribution according to the intensity distribution of the addressing light E2; and a transparent electrode layer 32 located between the impedance changing layer 33 and the back surface 3b. Furthermore, the liquid crystal layer 36 may also have partition walls 39a that divide the nematic liquid crystal 36a into regions corresponding to pixels. When the addressing light E2 is irradiated onto the back surface 3b of the spatial light modulator 3, the impedance distribution of the impedance changing layer 33 becomes a distribution corresponding to the intensity distribution of the addressing light E2. When a voltage is applied between the transparent electrode layer 37 and the transparent electrode layer 32, pixels with low impedance in the impedance changing layer 33 generate a strong electric field in the liquid crystal layer 36. Furthermore, pixels with high impedance in the impedance variation layer 33 generate a weak electric field in the liquid crystal layer 36. Therefore, according to this image output device 1A, each pixel in the spatial light modulator 3 can achieve a structure that changes the phase modulation amount according to the intensity of the addressing light E2 illuminating the back side 3b of each pixel. In addition, by having partition walls 39a in the liquid crystal layer 36 that divide the nematic liquid crystal 36a into regions corresponding to each pixel, the interaction between the nematic liquid crystals 36a between pixels can be reduced, and the phase pattern corresponding to the diffraction grating pattern can be made clearer.

[0116] As in this embodiment, the partition wall 39a may extend along the first direction D1 and the second direction D2 of the main surface 3a, and the spacing between adjacent partition walls 39a along the second direction D2 may be greater than the spacing between adjacent partition walls 39a along the first direction D1. In this case, since the orientation of the nematic liquid crystal 36a is easy to align, the light transmittance / non-transmittance of the nematic liquid crystal 36a for a specific polarized light direction can be effectively utilized.

[0117] As in this embodiment, the spacing between adjacent partition walls 39a along the second direction D2 can be more than twice the spacing between adjacent partition walls 39a along the first direction D1. According to the inventors, in this case, since the orientation of the nematic liquid crystal 36a is particularly easy to align, the light transmittance / non-transmittance of the nematic liquid crystal 36a for a specific polarized light direction can be effectively utilized.

[0118] As in this embodiment, the spacing between adjacent partition walls 39a along the first direction D1 and the spacing between adjacent partition walls 39a along the second direction D2 can both be 5 μm or less. By constructing the partition walls 39a with small intervals as described above, the pixel size of the spatial light modulator 3 can be reduced, thereby shortening the period of the diffraction grating. Therefore, as will be described later, the diffraction angle of the two-dimensional optical image of the spatial light modulator 3 can be increased, and the output direction of the stereoscopic image can be made closer to the plane containing the main surface 3a of the spatial light modulator 3, thereby providing a practical stereoscopic image to an observer A present around the spatial light modulator 3.

[0119] As in this embodiment, the impedance variation layer 33 may also comprise at least one of hydrogenated amorphous silicon, GaN-based compounds, InP-based compounds, and GaAs-based compounds. The impedance of these materials changes when light is received. Therefore, in this case, an impedance variation layer 33 that reflects the impedance distribution according to the intensity distribution of the addressing light E2 can be appropriately implemented.

[0120] As in this embodiment, the addressing light irradiation unit 4A may also include: a plurality of light-emitting units 42 arranged circumferentially and capable of outputting addressing light E2 containing a diffraction grating pattern, respectively; and an optical system 43 optically coupling the plurality of light-emitting units 42 to the back surface 3b. Furthermore, a portion of the light-emitting units 42 selected from the plurality of light-emitting units 42 that corresponds to the desired direction of the diffraction grating pattern can also output the addressing light E2. In this case, the mechanical drive unit can be eliminated, thereby improving reliability. Additionally, by including a superlens in the optical system 43, a large-area and thin optical system 43 can be realized, and addressing light E2 with a relatively large range can be irradiated onto the back surface 3b of the spatial light modulator 3.

[0121] As in this embodiment, the image output device 1A may also include a filter 15 disposed between the high-speed projector 2A and the spatial light modulator 3 to reduce the intensity of at least a portion of the wavelength components other than visible light contained in the two-dimensional optical image. This reduces the amount of incident light E1 onto the impedance change layer 33 and decreases the influence of light E1 on the phase modulation amount of the spatial light modulator 3.

[0122] As in this embodiment, each pixel can also be divided by a transparent electrode layer 32, an impedance variation layer 33, a dielectric reflector 34, and a liquid crystal alignment film 35, with each pixel separated by a gap GA. In this case, crosstalk between adjacent pixels can be reduced.

[0123] As described above, the light-emitting unit 42 may also have: a PCSEL having an active layer and a photonic crystal layer, and a periodic structure provided on the light-emitting surface of the PCSEL having an opening and a light-blocking portion that are periodically repeated according to a diffraction grating. In this case, the light-emitting unit 42 that outputs addressing light containing a diffraction grating pattern can be appropriately realized.

[0124] Here, the diffraction grating implemented in the spatial light modulator 3 will be described in detail. Figure 13 The diagram shows the periodic alternation of region P1 (with a phase modulation of 0 rad) and region P2 (with a phase modulation of π rad). Line B1 in the diagram represents the wavefront when a two-dimensional optical image incident from the normal direction of the principal surface 3a is diffracted by this diffraction grating. In this example, the relationship between the diffraction angle θ, the wavelength λ of the two-dimensional optical image, and the spacing L between regions P1 and P2 is expressed by the following equation (1):

[0125] 2Lsinθ=λ……(1).

[0126] Furthermore, the diffraction angle θ refers to the angle formed by the normal direction Da of the incident direction (which is the two-dimensional optical image) and the normal direction Db of the wavefront (i.e., the light exit direction), which is equal to the angle formed by the principal plane 3a and the wavefront B1. For example, when the diffraction angle θ is set to 30°, it can be set as L = λ.

[0127] However, in this case, such as Figure 14 As shown, viewed from the normal direction of principal surface 3a, wavefront B2, which propagates in the opposite direction to wavefront B1, is also simultaneously generated. The diffraction angle θ of wavefront B2 is equal to the diffraction angle θ of wavefront B1. That is, wavefront B2 emerges along a direction that is symmetrical about the axis of wavefront B1 with respect to the normal of principal surface 3a. Therefore, for... Figure 1 Another observer at a relative position to observer A can also observe the same two-dimensional optical image. Therefore, at various positions around the spatial light modulator 3, the two-dimensional optical image that should originally be shown overlaps with the two-dimensional optical image that should be shown at a position moved 180° from that position.

[0128] Such an observation method is not a problem when permissible, but there are also situations where it is not allowed. Therefore, in this embodiment, as... Figure 15 As shown, a unit PU is composed of three regions P1 to P3. Within each of the multiple units PU, the regions are arranged in the following order: region P1 with a phase modulation of 0 (rad), region P2 with a phase modulation of 2π / 3 (rad), and region P3 with a phase modulation of 4π / 3 (rad). Region P1 with a phase modulation of 0 (rad) corresponds to... Figures 9-12 Region E2a. Region P2, with a phase modulation of 2π / 3 (rad), corresponds to... Figures 9-12 Region E2b. Region P3, with a phase modulation of 4π / 3 (rad), corresponds to... Figures 9-12 Region E2c. When the arrangement spacing of regions P1 to P3 is set to L, the spacing of each unit PU, that is, the period of the diffraction grating, is 3L (=Λ). In addition, the interval between a certain wavefront B1 and the next generated wavefront B1 is mλ (m is an integer). That is, the following equation (2) holds:

[0129] 3Lsinθ=Λsinθ=mλ……(2).

[0130] Furthermore, the spacing L is set to the long side direction of each pixel of the spatial light modulator 3. Figure 4 Above the length of the first direction D1) of (a), in appropriate examples, the spacing L is equal to the length of the long side direction of each pixel of the spatial light modulator 3.

[0131] Figure 16 (a) is a graph showing the relationship between the period Λ and the diffraction angle θ (=0°~90°) when the period Λ of the diffraction grating is normalized with wavelength λ (where m=1). Figure 16 (b) magnified view Figure 16 In diagram (a), the diffraction angle θ = 5° to 30° is in the range. Figure 16 (c) magnified to show Figure 16 The portion of the graph in (a) showing diffraction angles θ = 30° to 90°. (Refer to...) Figure 16 From (b), it can be seen that, for example, to achieve a diffraction angle θ ≥ 10°, Λ ≤ 6λ must be satisfied. In other words, it is desirable that the period Λ of the diffraction grating is less than 6 times the wavelength λ. Thus, a diffraction angle θ ≥ 10° can be achieved. Furthermore, referring to… Figure 16 From C, we know that, for example, to achieve a diffraction angle θ ≥ 30°, Λ ≤ 2λ must be satisfied. In other words, we want the period Λ of the diffraction grating to be less than twice the wavelength λ. Thus, a diffraction angle θ ≥ 30° can be achieved.

[0132] Figure 17 (a) is a graph showing the relationship between the spacing L and the diffraction angle θ (=0°~70°) when the spacing L is normalized with respect to the wavelength λ (where m=1). Figure 17 (b) magnified view Figure 17 The portion of the chart in (a) with spacing L = 0 to 2λ. When referring to Figure 17 In case (a), when the spacing L is greater than 4λ, the diffraction angle θ is less than 5°. Additionally, when referring to... Figure 17 In (b), when L=0.355λ, θ=70°; when L=0.435λ, θ=50°; when L=0.667λ, θ=30°; when L=0.975λ, θ=20°; when L=1.920λ, θ=10°.

[0133] Figure 18 (a) is a graph showing, for example, the relationship between the spacing L and the diffraction angle θ (=0°~70°) (where m=1) in the case of wavelength λ=532nm. Figure 18 (b) magnified view Figure 18 The portion of the graph in (a) with a spacing L = 0 nm to 1000 nm. When referring to... Figure 18 In (a), when the spacing L is greater than 2 μm, the diffraction angle θ is less than 5°. Additionally, when referring to... Figure 18 In (b), when L = 188.7 nm, θ = 70°; when L = 231.5 nm, θ = 50°; when L = 354.7 nm, θ = 30°; when L = 518.5 nm, θ = 20°; and when L = 1021.2 nm, θ = 10°.

[0134] Here, we investigate the presence or absence of other diffraction angles that differ from the diffraction angle θ in the design described above. Figure 19 To show in more detail Figure 15 The graph shows the relationship between the diffraction angle θ and the phase modulation amount of each region P1 to P3. Figure 19 As shown, the phase modulation of region P1 in a certain unit PU is 0°, the phase modulation of region P2 is (1 / 3)Λsinθ=Lsinθ=(1 / 3)mλ, and the phase modulation of region P3 is (2 / 3)Λsinθ=2Lsinθ=(2 / 3)mλ. When the phase modulation of region P1 in the adjacent unit PU is Λsinθ=3Lsinθ=mλ, the angle (i.e., the diffraction angle) formed by the wavefront B1 and the principal surface 3a at the same time (i.e., when the values ​​of m are equal) of the adjacent pixels is θ. However, the angle formed by the wavefront and the principal surface 3a at different times (i.e., when the values ​​of m are different) of the adjacent pixels can be a different diffraction angle. Figure 20 The example shown illustrates wavefront B3 generated at a certain moment from region P2, and wavefront B3 generated at the previous moment from region P1, with the angle θ between wavefront B3 and principal surface 3a. B The size of this angle is different from the diffraction angle θ mentioned above. Furthermore, this angle θ B It satisfies the following equation (3):

[0135] Lsinθ B =λ-Lsinθ……(3).

[0136] When summarizing this equation, by intensifying the waves of the nth preceding wave (n is an integer) in the adjacent region, a diffraction angle θ is generated that satisfies the following equation (4). B Wavefront B3:

[0137] Lsinθ B=nλ-insinθ……(4).

[0138] Next, the relationship between the spacing L used to achieve an arbitrary diffraction angle θ and the phase difference between adjacent regions will be explained. Figure 21 (a) is a graph showing the relationship between the spacing L and the diffraction angle θ, which satisfies the above equation (2), for example, when the wavelength λ is 532 nm. Figure 21 (b) is shown in magnification. Figure 21 The graphs in (a) show the portion with a spacing of L to 2 μm. Among these graphs, five graphs are shown corresponding to each m = 1 to 5. Figure 22 This is a graph showing the correlation between the phase difference between adjacent regions and the value of m. Based on these graphs, it can be seen that, for example, to achieve a diffraction angle θ = 40° when m = 1, the spacing can be set to L = 276 nm, or to achieve a diffraction angle θ = 40° when m = 2, the spacing can be set to L = 552 nm.

[0139] Figure 23 This shows that, with a wavelength λ = 532 nm, when the diffraction angle θ is assigned to the design, the spacing L that satisfies the above equation (2) is obtained, and the diffraction angle θ is obtained by substituting the spacing L into the following equation (5). B Chart of the results:

[0140]

[0141] In addition, the phase difference of adjacent regions Let it be 2π / 3. The diffraction angle θ when n = 0. B It is consistent with the diffraction angle θ.

[0142] As another example, Figure 24 (a) is a graph showing the relationship between the spacing L and the diffraction angle θ that satisfies the above equation (2) when the wavelength λ is 467 nm. Figure 24 (b) is shown in magnification. Figure 24 The graphs in (a) show the portion with a spacing of L to 2 μm. Among these graphs, five graphs are shown corresponding to each m = 1 to 5. Figure 25 This is a graph showing the correlation between the phase difference between adjacent regions and the value of m. Based on these graphs, it can be seen that, for example, to achieve a diffraction angle θ = 40° when m = 1, the spacing can be set to L = 242 nm, or to achieve a diffraction angle θ = 40° when m = 2, the spacing can be set to L = 484 nm.

[0143] Figure 26 This shows that when the wavelength λ = 467 nm is given a diffraction angle θ in the design, the spacing L that satisfies the above equation (2) is obtained, and the diffraction angle θ is obtained by substituting the spacing L into the above equation (5).B The results are presented in a graph. Additionally, the phase difference in adjacent regions... Let it be 2π / 3. The diffraction angle θ when n = 0. B It is consistent with the diffraction angle θ.

[0144] As another example, Figure 27 (a) is a graph showing the relationship between the spacing L and the diffraction angle θ that satisfies the above equation (2) when the wavelength λ is 630 nm. Figure 27 (b) is shown in magnification. Figure 27 The graphs in (a) show the portion with a spacing of L to 2 μm. Among these graphs, five graphs are shown corresponding to each m = 1 to 5. Figure 28 This is a graph showing the correlation between the phase difference between adjacent regions and the value of m. Based on these graphs, it can be seen that, for example, to achieve a diffraction angle θ = 40° when m = 1, the spacing can be set to L = 327 nm, or to achieve a diffraction angle θ = 40° when m = 2, the spacing can be set to L = 653 nm.

[0145] Figure 29 This is a graph showing the results of obtaining the spacing L satisfying the above equation (2) when the wavelength λ = 630 nm is given a diffraction angle θ in the design, and substituting the spacing L into the above equation (5) to obtain the diffraction angle θB. Furthermore, the phase difference of adjacent regions... Let it be 2π / 3. The diffraction angle θ when n = 0. B It is consistent with the diffraction angle θ.

[0146] Figure 30 (a) is a figure showing an example of a suitable diffraction grating based on the above research results. Figure 30 (b) is a locally magnified view. Figure 30 Figure (a). Furthermore, in these... Figure 30 (a) and Figure 30 In (b), the phase modulation amount is represented by the intensity of color; areas with large phase modulation amounts are represented by lighter colors, and areas with small phase modulation amounts are represented by darker colors. For example... Figure 30 (a) and Figure 30 As shown in (b), in this diffraction grating, regions Fa (with a phase modulation of 0), Fb (with a phase modulation of 2π / 3 rad), and Fc (with a phase modulation of 4π / 3 rad) are repeatedly arranged in sequence along their respective short sides. In one example, the width (i.e., the spacing L) of each region Fa to Fc in the arrangement direction of the diffraction grating is 518 nm. In this case, as... Figure 23 As shown, light E1 with wavelength λ = 532 nm diffracts at angles θ and θ' = 43.2° and -20.0° respectively. B Bias.

[0147] In order to realize the diffraction grating generated by the phase modulation of the spatial light modulator 3 with high precision, the relationship between the phase modulation amount of the spatial light modulator 3 and the light intensity of the addressing light E2 (γ characteristic) can be obtained in advance. Figure 31 This is a graph conceptually illustrating the relationship between the phase modulation amount of the spatial light modulator 3 and the light intensity of the addressing light E2. For example... Figure 31 As shown, the relationship between the phase modulation amount of the spatial light modulator 3 and the light intensity of the addressing light E2 is nonlinear in many cases.

[0148] The diffraction grating pattern contained in the addressing light E2 is adjusted from... Figure 8 The intensity of the light emitted from the light-emitting regions 42b and 42c of the light-emitting surface 42a shown is achieved by adjusting the intensity of the light emitted from these regions. The intensity of the light emitted from the light-emitting regions 42b and 42c can also be adjusted by increasing the driving current supplied to the light-emitting regions 42b and 42c respectively, or by using a method including... Figure 32 The light-shielding film of the light-shielding pattern 80 shown in (a) is used to cover the light-emitting areas 42b and 42c. Furthermore, Figure 32 The light-shielding pattern shown in (a) is constructed by comprising multiple mutually separated light-shielding regions 81, and the multiple light-shielding regions 81 are located at grid points of various grids such as triangular grids or square grids. The planar shape of the light-shielding regions 81 can also be as follows: Figure 32 (b) is shown as circular, or it can also be as shown in the diagram. Figure 32 (c) shows a quadrilateral (e.g., a square or rectangle). Alternatively, the planar shape of the light-shielding region 81 can also be various other shapes. By adjusting the area ratio occupied by the multiple light-shielding regions 81 (i.e., the size and spacing of each light-shielding region 81), the intensity of the light emitted from the light-emitting regions 42b and 42c can be adjusted. Furthermore, to suppress light diffraction, the center-to-center spacing (pitch) between adjacent light-shielding regions 81 can be below the wavelength of the addressing light E2. Figure 32 (d) is a top view showing an example of a light-shielding film. In this example, the aforementioned light-shielding pattern 80 is applied to... Figures 9-12 The area E2b shown corresponds to the area Ab of the light-shielding film. Not limited to this example, in addition to area Ab, at least one of the areas Aa of the light-shielding film corresponding to area E2a and Ac of the light-shielding film corresponding to area E2c may also be applied with the light-shielding pattern 80.

[0149] In the above description, the diffraction grating includes: a region Fa with small (or essentially zero) phase modulation, a region Fb with slightly larger phase modulation, and a region Fc with large phase modulation. The example given is a diffraction grating constructed by sequentially repeating these three regions Fa to Fc along the short side direction. In this case, the diffraction grating pattern of the addressing light E2 has a structure where the light intensity changes periodically in a certain direction. Within each period, the light intensity increases or decreases monotonically in stages, and the number of regions E2a to E2c with different light intensities in each period is three, with the light intensity changing in two stages. However, the diffraction grating and the addressing light E2 are not limited to this method. A diffraction grating can also be constructed by sequentially repeating N regions (N being an integer greater than or equal to 3) along the short side direction, where the phase modulation can also change monotonically from one end of the arrangement direction of these N regions to the other. In other words, the diffraction grating pattern of the addressing light E2 is constructed by sequentially repeating N regions along the short side in the long side direction. The light intensity increases or decreases in stages within each repetition period. The number of regions with different light intensities in each period is N, and the light intensity can also vary in (N-1) stages within each repetition period. Even in this case, the bias in the opposite direction to the desired bias direction of the two-dimensional optical image can be reduced (see...). Figure 14 It can output 3D images more clearly.

[0150] Here, Figure 33 of (a), Figure 33 (b) Figure 34 (a) and Figure 34 (b) is a diagram conceptually illustrating the method for determining the phase modulation amount in each region constituting the diffraction grating. Furthermore, in Figure 33 (a)~ Figure 34 The example diffraction grating shown in (b) has each unit PU containing four regions P1 to P4 (i.e., N = 4). In these figures, the horizontal axis represents the position of the diffraction grating in the periodic direction (the arrangement direction of regions P1 to P4), and the vertical axis represents the output phase. When implementing a diffraction grating, as... Figure 33 (a) and Figure 34 As shown in (a), the output phase can be monotonically increased in the diffraction direction. As an example, these figures show the case where the output phase changes linearly in the diffraction direction. Furthermore, in practice, the phase modulation amount for each region P1–P4 can be set as the remainder when the output phase is divided by 2π. Figure 33 (a) and Figure 34 In (a), the remainder when the output phase is divided by 2π is shown in gray. Additionally, Figure 33 (b) and Figure 34(b) shows the phase modulation amounts of regions P1 to P4. To ensure that the phase modulation amounts of each unit PU are consistent, the phase difference between the output phases of adjacent unit PUs is preferably an integer multiple of 2π, more preferably 2π. This is because, when the phase difference between the output phases of adjacent unit PUs is not an integer multiple of 2π, the diffracted light caused by the period of the unit PU generates higher-order components, which superimpose as weak noise light onto light E1.

[0151] Furthermore, as mentioned above, the diffraction angle of light E1 from the spatial light modulator 3 depends on the wavelength of light E1. Therefore, when light E1 contains multiple wavelength components, the diffraction angle is different for each wavelength component, and the optical images of each wavelength component presented to the observer A are staggered. Therefore, when light E1 contains multiple wavelength components, by illuminating each wavelength component sequentially with extremely short periods instead of simultaneously, and by varying the lattice spacing according to each wavelength component, the diffraction angle can be kept constant.

[0152] Furthermore, this embodiment has a structure in which each pixel 30 of the spatial light modulator 3 changes its phase modulation amount according to the intensity of the addressing light E2. The same function can be achieved by configuring an independent electrode for each pixel 30 and applying a voltage to each electrode individually. However, to provide an optical image at the eye height Aa of observer A, a relatively large diffraction angle of, for example, 30° or more is desired. In this case, the spacing L of each region constituting the diffraction grating is extremely small, around 1 μm to several μm. Since the arrangement spacing of the pixels 30 of the spatial light modulator 3 needs to be less than this spacing L, the arrangement spacing of the electrodes becomes extremely small, making it difficult to achieve the area required for the driving circuit. As in this embodiment, by having a structure in which the pixel 30 changes its phase modulation amount according to the intensity of the addressing light E2, wiring that connects to each electrode individually is not required, the arrangement spacing of the pixels 30 can be reduced, and a relatively large diffraction angle can be achieved.

[0153] (First variation)

[0154] Figure 35 (a) and Figure 35 Figure (b) is a diagram showing the structure of a first modified example of the above embodiment. The image output device 1A of the above embodiment may also have Figure 35 The miniature LED panel 2B shown in (a) is used to replace Figure 1 The high-speed projector 2A is shown. The micro-LED panel 2B is an example of the image illumination unit in this modified example; it is a self-emissive high-resolution display that illuminates light E1 containing a two-dimensional optical image onto the main surface 3a of the spatial light modulator 3. In this modified example, the incident direction of the light E1 onto the main surface 3a is also consistent with the normal direction of the main surface 3a of the spatial light modulator 3. The output wavelength and frame rate of the micro-LED panel 2B are the same as those of the high-speed projector 2A in the above embodiment.

[0155] A filter 15 is provided in the optical path between the micro-LED panel 2B and the spatial light modulator 3. The structure and function of the filter 15 are the same as in the above embodiment. Furthermore, in this modified example, the lens 16 of the above embodiment may not be provided (see [reference]). Figure 2 This is because the light from the miniature LED panel 2B will be imaged on the retina of observer A's eye Aa, even when viewed as is.

[0156] In addition, the image output device 1A of the above embodiment may also have Figure 35 (b) shows multiple high-speed projectors 2C to 2E (in) Figure 35 In the example shown in (b), three are used, along with wavelength synthesis unit 21, to replace... Figure 1 The high-speed projector 2A is shown. High-speed projectors 2C to 2E are devices that output two-dimensional optical images of a single wavelength, and each outputs a different wavelength. In one example, high-speed projector 2C outputs a two-dimensional optical image in the red domain, high-speed projector 2D outputs a two-dimensional optical image in the green domain, and high-speed projector 2E outputs a two-dimensional optical image in the blue domain. High-speed projectors 2C to 2E are individually optically coupled to a wavelength combining unit 21. The wavelength combining unit 21 is, for example, a cross-shaped dichroic prism, which combines the two-dimensional optical images output from high-speed projectors 2C to 2E and outputs them as light E1. The cross-shaped dichroic prism has: a first multilayer film that reflects light in the blue domain and transmits light in the green domain; and a second multilayer film that reflects light in the red domain and transmits light in the green domain, the first and second multilayer films being combined in an X-shape.

[0157] For example, as in this modified example, the image illumination unit is not limited to the above-described embodiment and can have various structures. The image output device 1A can achieve the effects of the above-described embodiment by having various image illumination units that illuminate the main surface 3a of the spatial light modulator 3 with light E1 containing a two-dimensional optical image. Furthermore, by means of... Figure 35 The example shown in (b) synthesizes light from multiple high-speed projectors, which can effectively achieve a speed several times higher than that of high-speed projectors.

[0158] (Second variation)

[0159] Figure 36 (a) is a second variation of the above embodiment, showing a side cross-sectional view of the structure of the addressing light irradiation unit 4B, and showing a cross-section of the normal to the back surface 3b of the spatial light modulator 3. Figure 36 (b) is a top view of the light-emitting device 41 and optical component 44 having an addressable light irradiation section 4B, showing the structure of the light-emitting device 41 and optical component 44 as viewed from the normal direction of the back surface 3b of the spatial light modulator 3.

[0160] The addressing light irradiation unit 4B irradiates the back surface 3b of the spatial light modulator 3 with addressing light E2 containing a diffraction grating pattern. The addressing light irradiation unit 4B has the same light-emitting device 41 as in the above embodiment, and replaces the optical system 43 of the above embodiment (see reference). Figure 2 The device includes an optical component 44 and an imaging lens 45. The optical component 44 has a concave mirror 44a disposed at the center of the annular light-emitting device 41. The imaging lens 45 is disposed between the optical component 44 and the back surface 3b of the spatial light modulator 3. The concave mirror 44a and the imaging lens 45 optically couple the plurality of light-emitting portions 42 of the light-emitting device 41 to the back surface 3b of the spatial light modulator 3. Specifically, the concave mirror 44a reflects the addressing light E2 emitted from the light-emitting portion 42 toward the back surface 3b of the spatial light modulator 3. The concave mirror 44a and the imaging lens 45 work together to image the diffraction grating pattern contained in the addressing light E2 on the back surface 3b. Furthermore, the concave mirror 44a has a curvature that selectively magnifies only the longitudinal direction of the light-emitting portion 42. As a result, the longitudinal length of the light-emitting portion 42 can be reduced. In addition, in order to selectively magnify only the longitudinal direction of the light-emitting portion 42, a cylindrical lens (not shown) may be disposed on the light-emitting surface 42a of each light-emitting portion 42. Cylindrical lenses can also be achieved using superlenses composed of subwavelength elements.

[0161] In the optical component 44, a rotation drive unit 401 is mounted via a rotation axis 402. The rotation axis 402 extends along the normal direction of the back surface 3b and rotates about an axis along the normal direction of the back surface 3b by a driving force from the rotation drive unit 401. As a result, the direction of the concave mirror 44a dynamically changes, and addressing light E2 from a portion of the light-emitting portions 42 selected from a plurality of light-emitting portions 42 corresponding to the direction of the desired diffraction grating pattern is incident on the back surface 3b of the spatial light modulator 3. Therefore, the direction of the diffraction grating pattern on the back surface 3b can be dynamically changed. In one example, the rotation axis 402 is rotated in one direction by a driving force from the rotation drive unit 401. In this case, the diffraction grating pattern rotates in one direction on the back surface 3b.

[0162] The image output device 1A of the above embodiment can achieve the same effect as the above embodiment even when it has the addressing light irradiation unit 4B of this modified example. In addition, in the above embodiment, a portion of the light-emitting units 42 selected from the plurality of light-emitting units 42 that corresponds to the direction of the desired diffraction grating pattern outputs the addressing light E2, but in this modified example, as in the above embodiment, all of the plurality of light-emitting units 42 may always output the addressing light E2.

[0163] (Third variation)

[0164] Figure 37(a) is a third variation of the above embodiment, showing a side cross-sectional view of the structure of the addressing light irradiation unit 4C, and showing a cross-section along the normal line of the back surface 3b of the spatial light modulator 3. Figure 37 (b) is a top view of the light-emitting device 46 having an addressable light irradiation section 4C, showing the structure of the light-emitting device 46 as viewed from the normal direction of the back surface 3b of the spatial light modulator 3. Figure 37 (c) shows along Figure 37 (b) A cross-sectional view of the light-emitting device 46 of line II.

[0165] The addressing light irradiation unit 4C irradiates the back surface 3b of the spatial light modulator 3 with addressing light E2 containing a diffraction grating pattern. In this modified example, the addressing light irradiation unit 4C has a light-emitting device 46 and an optical system 47. The light-emitting device 46 is circular, having a main surface 46a and a back surface 46e opposite to the main surface 46a. Furthermore, the light-emitting device 46 has a light-emitting portion 46b disposed on the main surface 46a. The planar shape of the light-emitting portion 46b is an annular shape disposed along the circumference. The central axis of this annular shape coincides with the central axis of the pixel group of the spatial light modulator 3. Figure 37 As shown in (c), the light-emitting unit 46b includes a plurality of light-emitting regions 46c arranged concentrically. By having such a plurality of concentrically arranged light-emitting regions 46c, the light-emitting unit 46b can output addressing light E2 comprising a diffraction grating pattern with the radial direction of the circumference set as the periodic direction. The plurality of light-emitting regions 46c can be appropriately configured, for example, using a surface-emitting semiconductor light-emitting element such as a light-emitting diode, a surface-emitting laser, etc. The surface-emitting laser can also be a VCSEL, a PCSEL, or an S-iPM laser (described later).

[0166] In addition, such as Figure 38 As shown in (a), the light-emitting portion 46b can also have a single annular light-emitting region 46g instead of multiple concentrically arranged light-emitting regions 46c. In this case, the light-emitting device 46 can have a periodic structure 46h of a light-shielding film on the main surface 46a. Furthermore, Figure 38 (b) is along Figure 38 A cross-sectional view of line II-II in (a). A periodic structure 46h is provided on the light-emitting surface of the light-emitting region 46g, and openings and light-blocking portions are periodically provided according to the diffraction grating pattern. Furthermore, in Figure 38 (a) and Figure 38 In the example shown in (b), the following are periodically set: corresponding to Figures 9-12The light-shielding portions 461 and 462 of regions E2a and E2b, and the opening 463 corresponding to region E2c, are shown. The light-emitting region 46g can be appropriately constructed, for example, using a surface-emitting semiconductor light-emitting element such as a light-emitting diode or a surface-emitting laser. The surface-emitting laser can also be a VCSEL, PCSEL, or S-iPM laser (described later).

[0167] Additionally, the light-emitting portion 46b includes multiple element electrodes 46d and a conductive film 46f formed on the main surface 46a. In one example, the conductive film 46f is a transparent conductive film, which is transmissive to the wavelength of the addressing light E2. Furthermore, in Figure 37 (b) and Figure 38 In (a), only one element electrode 46d is shown as representative. Multiple element electrodes 46d are disposed on the back surface 46e of the light-emitting device 46 and arranged circumferentially. In one example, the planar shape of each element electrode 46d is a fan shape centered on the center of the annulus of the light-emitting portion 46b. These element electrodes 46d selectively emit the addressing light E2 by supplying a driving current to the conductive films 46f between portions of the light-emitting portion 46b corresponding to the direction of the desired diffraction grating pattern on the back surface 3b of the spatial light modulator 3. Thus, the direction of the diffraction grating pattern on the back surface 3b can be dynamically changed. In one example, each circumferential element electrode 46d sequentially emits light from the light-emitting portion 46b. In this case, the diffraction grating pattern rotates in one direction on the back surface 3b.

[0168] An optical system 47 is disposed between the light-emitting device 46 and the spatial light modulator 3, and optically couples the light-emitting part 46b to the back surface 3b of the spatial light modulator 3. The optical axis of the optical system 47 is aligned with the central axis of the annulus of the light-emitting part 46b. The shape of the optical system 47, in the cross-section including the central axis of the annulus, may include, for example, a convex lens. Alternatively, the shape of the optical system 47 in the cross-section including the central axis of the annulus may also include a superlens. When the optical system 47 includes a superlens, the thickness of the optical system 47 in the optical axis direction can be reduced. Furthermore, the shape of the optical system 47 is not limited to these; various other shapes may be adopted if they are shapes that allow the addressing light E2 to be imaged on the back surface 3b.

[0169] The addressing light irradiation unit 4A in the above embodiment can also be replaced by the addressing light irradiation unit 4C in this modified example. According to the structure of this modified example, unlike the addressing light irradiation unit 4A, the addressing light irradiation unit 4C can be appropriately realized by using planar processing instead of circumferential assembly, allowing the direction of the diffraction grating pattern on the back surface 3b to change dynamically. Furthermore, in the above example, multiple element electrodes 46d are provided on the back surface 46e of the light-emitting device 46; alternatively, the conductive film 46f on the main surface 46a side can be divided into multiple element electrodes, and a single electrode can be provided on the back surface 46e.

[0170] (Fourth variation)

[0171] Figure 39 This diagram schematically illustrates the structure of the addressing light irradiation unit 4D, a fourth modification of the above embodiment. The addressing light irradiation unit 4D irradiates the back surface 3b of the spatial light modulator 3 with addressing light E2 containing a diffraction grating pattern. The addressing light irradiation unit 4D of this modification includes: a laser source 403, a beam expander 404, a polarizing beam splitter 405, a half-wavelength plate (λ / 2 plate) 406, a reflector 407, a tilting mirror 408, and a rotation drive unit 409.

[0172] Laser source 403 outputs laser E3 with the same wavelength as addressing light E2. Beam expander 404 is optically coupled to laser source 403, which expands the optical path of laser E3 output from laser source 403 and outputs it in a parallel manner.

[0173] The polarization beam splitter 405 is an example of a branching section in this modification, and it branches the laser E3 output from the laser source 403 into two lasers, E31 and E32. Specifically, the polarization beam splitter 405 is optically coupled to the laser source 403 via the beam expander 404, and the laser E3 received from the laser source 403 branches into two lasers, E31 and E32, according to the polarization direction. The polarization direction of the laser E3 is tilted at an angle greater than 0° and less than 90° (e.g., 45°) relative to the polarization direction of the polarization beam splitter 405 that has transmission characteristics. Therefore, the polarization component of the laser E3 parallel to the polarization direction of the polarization beam splitter 405 passes through the polarization beam splitter 405 to become laser E31, and the polarization component of the laser E3 orthogonal to the polarization direction of the polarization beam splitter 405 is reflected by the polarization beam splitter 405 to become laser E32.

[0174] The half-wavelength plate 406 is optically coupled to the laser source 403 via a polarizing beam splitter 405 and a beam expander 404. It receives the laser E31 output from the polarizing beam splitter 405 and rotates the polarization direction of the laser E31 by 90° by changing its phase by 180°. As a result, the polarization direction of the laser E31 after passing through the half-wavelength plate 406 is consistent with the polarization direction of the laser E32.

[0175] Reflector 407 and tilting mirror 408 constitute the interference optical system in this modified example. Reflector 407 is optically coupled to laser source 403 via half-wavelength plate 406 and polarizing beam splitter 405, and reflects laser E31, which passes through polarizing beam splitter 405 and half-wavelength plate 406, toward the back surface 3b of spatial light modulator 3. Tilting mirror 408 is optically coupled to laser source 403 via polarizing beam splitter 405, and reflects laser E32, which is branched by polarizing beam splitter 405, toward the back surface 3b of spatial light modulator 3. Reflector 407 and tilting mirror 408 are arranged opposite to each other, so that when viewed from the normal direction of back surface 3b, lasers E31 and E32 are directed toward back surface 3b from opposite directions. Reflector 407 and tilting mirror 408 cause lasers E31 and E32, which are branched by polarizing beam splitter 405, to interfere with each other, generating interference fringes on the back surface 3b of spatial light modulator 3. The interference fringes on the back side 3b serve as a diffraction grating pattern for the addressing light E2.

[0176] The rotation drive unit 409 and the tilt mirror 408 constitute the position change unit in this modified example, dynamically changing the relative positional relationship of lasers E31 and E32 during interference. Specifically, the tilt mirror 408 is connected to the rotation drive unit 409 via a rotation shaft 410 and receives the driving force from the rotation drive unit 409, performing a rotation operation around a predetermined axis. Furthermore, the normal direction of the light-reflecting surface of the tilt mirror 408 is slightly tilted relative to the predetermined axis. When the tilt mirror 408 rotates around the predetermined axis, the optical axis of laser E32 also rotates and moves by a small radius. As a result, on the back surface 3b of the spatial light modulator 3, the relative position of the irradiation point of laser E32 relative to the irradiation point of laser E31 moves along a certain circle. Therefore, the diffraction grating pattern of the address light E2, which forms the interference fringes of lasers E31 and E32, rotates in one direction on the back surface 3b.

[0177] As in this modified example, the interference fringes can also be used as a diffraction grating pattern. In this case, as in this modified example, by dynamically changing the relative positional relationship between the interference of one laser E31 and another laser E32 constituting the interference fringes, the direction of the interference fringes, i.e., the direction of the diffraction grating pattern, can be dynamically changed. Furthermore, the dynamic change of the direction of the diffraction grating pattern is not limited to rotation of the diffraction grating pattern, but can also be a rotation operation within a certain finite angular range. In addition, a polarizing beam splitter 405 and a half-wavelength plate 406 are used in the above example, but a half-reflecting mirror or the like can also be used instead of a polarizing beam splitter to branch the laser E3. In this case, the half-wavelength plate 406 is unnecessary.

[0178] (Fifth variation)

[0179] Figure 40Figure (a) schematically illustrates the structure of the addressing light irradiation unit 4E, a fifth modification of the above embodiment. The addressing light irradiation unit 4E irradiates the back surface 3b of the spatial light modulator 3 with addressing light E2 containing a diffraction grating pattern. The addressing light irradiation unit 4E of this modification includes: an annular light-emitting device 49 and an optical system including an optical member 48 disposed inside the light-emitting device 49. Figure 40 (b) is a top view of the light-emitting device 49 viewed from the axial direction of the ring. For example... Figure 40 (a) and Figure 40 As shown in (b), the light-emitting device 49 is configured to include multiple surface-emitting laser element arrays 50. Each surface-emitting laser element array 50 is an example of a light-emitting part in this modified example. The multiple surface-emitting laser element arrays 50 are arranged side by side along the circumference with the light-emitting surface 50a facing inward. The surface-emitting laser element array 50 in this modified example is composed of multiple surface-emitting laser elements arranged in one-dimensional or two-dimensional order. Each surface-emitting laser element outputs an arbitrary optical image by controlling the phase spectrum and intensity spectrum of the light emitted from the multiple light-emitting points arranged in a two-dimensional order. Such a surface-emitting laser element is called an S-iPM (Static-integerable Phase Modulating) laser, which can output a two-dimensional, arbitrary-shaped optical image that also includes a direction perpendicular to the main surface of the semiconductor substrate and a direction tilted to it. Therefore, by appropriately designing the phase spectrum and intensity spectrum of the output light in advance, the surface-emitting laser element array 50 can realize the inclusion of a diffraction grating pattern (e.g., as shown in the image) in the far field of view. Figures 9-12 The image is formed on the back side 3b by addressing light E2 in three regions E2a to E2c with different light intensities, which are repeated sequentially.

[0180] The optical component 48 has a flat reflector 48a disposed at the center of the annular light-emitting device 49. The reflector 48a optically couples the array of multiple surface-emitting laser elements 50 of the light-emitting device 49 to the back surface 3b of the spatial light modulator 3. That is, the reflector 48a reflects the addressing light E2 emitted from the surface-emitting laser element array 50 toward the back surface 3b of the spatial light modulator 3.

[0181] In the optical component 48, a rotation drive unit 401 is mounted via a rotation axis 402. The rotation axis 402 extends along the normal direction of the back surface 3b and rotates about an axis along the normal direction of the back surface 3b by a driving force from the rotation drive unit 401. As a result, the orientation of the reflector 48a dynamically changes, allowing addressing light E2 from a portion of the surface-emitting laser element array 50 selected from multiple surface-emitting laser element arrays 50 that corresponds to the orientation of the desired diffraction grating pattern to be incident on the back surface 3b of the spatial light modulator 3. Therefore, the orientation of the diffraction grating pattern on the back surface 3b can be dynamically changed. In one example, the rotation axis 402 is rotated in one direction by a driving force from the rotation drive unit 401. In this case, the diffraction grating pattern rotates in one direction on the back surface 3b.

[0182] In addition, such as Figure 41 As shown in (a), the addressing light E2 can also directly illuminate the back surface 3b from the surface-emitting laser element array 50 without passing through the optical component 48, or, as... Figure 41 As shown in (b), the back surface 3b can also be illuminated from the surface-emitting laser element array 50 via lens 54. Additionally, as... Figure 41 As shown in (c), the superlens 55 can also be formed on the light-emitting surface 50a and integrated with the surface-emitting laser element array 50. According to Figure 41 (a)~ Figure 41 The structure shown in (c) eliminates the need for optical components 48, thus enabling electrical switching without a mechanical rotation mechanism. Therefore, it becomes a structure suitable for large-scale and high-speed applications.

[0183] Figure 42This diagram schematically illustrates the structure of the addressing light irradiation unit 4F, another structure as a variation of this example. The addressing light irradiation unit 4F also irradiates the back surface 3b of the spatial light modulator 3 with addressing light E2 containing a diffraction grating pattern. The addressing light irradiation unit 4F has a surface-emitting laser element array 50 and a rotation drive unit 401. The surface-emitting laser element array 50 is arranged below the spatial light modulator 3, with its emitting surface 50a facing the back surface 3b of the spatial light modulator 3. The rotation drive unit 401 is mounted on the surface-emitting laser element array 50 via a rotation axis 402. The rotation axis 402 extends along the normal direction of the back surface 3b and dynamically changes its attitude angle about the normal direction of the back surface 3b by a driving force from the rotation drive unit 401. This dynamically changes the orientation of the diffraction grating pattern on the back surface 3b. In one example, the rotation axis 402 is rotated in one direction by the driving force from the rotation drive unit 401. In this configuration, the diffraction grating pattern rotates in one direction on the back surface 3b. As described above, the addressing light irradiation unit 4F may include: a light-emitting unit (surface-emitting laser element array 50) that outputs addressing light E2 containing the diffraction grating pattern; and a driving unit (rotation driving unit 401) that dynamically changes the attitude angle about the optical axis of the light-emitting unit. In this configuration, an addressing light irradiation unit that dynamically changes the orientation of the diffraction grating pattern on the back surface 3b can be appropriately implemented. Furthermore, in this modified example, the attitude angle of the surface-emitting laser element array 50 is dynamically changed, but the same structure as this modified example can also be used to dynamically change the orientation angle of the diffraction grating pattern on the back surface 3b. Figure 8 The posture angle of the light-emitting part 42 shown changes dynamically.

[0184] Here, the surface-emitting laser elements constituting the surface-emitting laser element array 50 will be described in detail. Figure 43 (a) is a cross-sectional view showing the structure of the surface-emitting laser element 52. An XYZ orthogonal coordinate system is defined with the axis extending along the thickness direction of the surface-emitting laser element 52 at its center as the Z-axis. The surface-emitting laser element 52 forms a standing wave in the in-plane direction of the XY plane and outputs addressing light E2 in the direction perpendicular to the main surface 53a of the semiconductor substrate 53 (Z direction).

[0185] The surface-emitting laser element 52 includes a semiconductor substrate 53 and a semiconductor stack 60 disposed on a main surface 53a of the semiconductor substrate 53. The semiconductor stack 60 includes a cladding layer 61 disposed on the main surface 53a, an active layer 62 disposed on the cladding layer 61, a cladding layer 63 disposed on the active layer 62, and a contact layer 64 disposed on the cladding layer 63. Additionally, the semiconductor stack 60 includes a phase modulation layer 65A. Figure 43In the example shown in (a), the phase modulation layer 65A is disposed between the active layer 62 and the cladding layer 63. The phase modulation layer 65A can also be disposed between the cladding layer 61 and the active layer 62. The addressing light E2 is output from the back surface 53b of the semiconductor substrate 53 and provided to the spatial light modulator 3. That is, the back surface 53b of the semiconductor substrate 53 is equivalent to... Figure 40 of (a), Figure 40 (b) and Figure 42 The luminescent surface 50a is in the middle.

[0186] The band gaps of cladding layers 61 and 63 are wider than those of active layer 62. The thickness directions of semiconductor substrate 53, cladding layers 61 and 63, active layer 62, contact layer 64, and phase modulation layer 65A are aligned with the Z-axis direction.

[0187] Phase modulation layer 65A is the layer that forms the resonant mode. Figure 43 (b) is an enlarged cross-sectional view showing the phase modulation layer 65A. The phase modulation layer 65A comprises a base layer 65a and multiple differential refractive index regions 65b. The base layer 65a is a semiconductor layer made of a first refractive index medium. The multiple differential refractive index regions 65b are made of a second refractive index medium with a different refractive index than the first refractive index medium and exist within the base layer 65a. The differential refractive index regions 65b may also be vias or may be formed by embedding compound semiconductors within the vias. The multiple differential refractive index regions 65b are arranged in a two-dimensional manner in a plane (XY plane) perpendicular to the thickness direction of the phase modulation layer 65A.

[0188] Figure 44 This is a top view of the phase modulation layer 65A. Here, a virtual square grid is set on the surface of the phase modulation layer 65A parallel to the XY plane. One side of the square grid is parallel to the X-axis, and the other side is parallel to the Y-axis. A square-shaped unit structure region R(x,y), centered on the grid point O(x,y) of the square grid, can be set in a two-dimensional manner, spanning multiple columns (x = 0–3) along the X-axis and multiple rows (y = 0–2) along the Y-axis. Multiple differential refractive index regions 65b are set sequentially within each unit structure region R. The planar shape of the differential refractive index region 65b is, for example, circular, but not limited to this; it can also be various shapes such as polygons, closed curves, or composed of two or more closed curves. Within the unit structure region R(x,y), the centroid G of the differential refractive index region 65b is configured to be separated from its nearest grid point O(x,y).

[0189] like Figure 45As shown, the position of the unit structure region (x, y) is assigned using an orthogonal coordinate system with the grid point O(x, y) as the origin (defined by the s-axis parallel to the X-axis and the t-axis parallel to the Y-axis). The angle between the direction from the grid point O(x, y) towards the centroid G and the s-axis is set as... Furthermore, component x represents the position of the x-th grid point on the x-axis, and component y represents the position of the y-th grid point on the y-axis. In rotation angle... When the angle is 0°, the direction of the vector connecting lattice point O(x, y) and the centroid G is aligned with the positive direction of the s-axis. Furthermore, the length of the vector connecting lattice point O(x, y) and the centroid G is set to r(x, y). In one example, r(x, y) is constant regardless of x and y (across the entire phase modulation layer 65A). Moreover, when the length r(x, y) = 0, the centroid G of the differential refractive index region 65b coincides with lattice point O(x, y), and the surface-emitting laser element 52 is a PCSEL.

[0190] In addition, such as Figure 44 As shown, in phase modulation layer 65A, the rotation angle of the centroid G of the differential refractive index 65b about lattice point O is... Based on the desired optical image, each unit structure region R is independently and individually defined. Within the unit structure region (x, y), the rotation angle distribution is... Each position determined by the values ​​of x and y has a specific value, but is not necessarily limited to being represented by a specific function. That is, the distribution of rotation angles. The phase distribution can be determined by extracting the complex amplitude distribution obtained from the inverse Fourier transform of the desired optical image. Furthermore, when the complex amplitude distribution is obtained from the desired optical image, the reproducibility of the beam pattern can be improved by applying a repetitive algorithm, such as the Gerechberg-Saxton (GS) method, which is commonly used in hologram generation calculations.

[0191] Figure 46 It is used to illustrate the optical image obtained by imaging the output beam pattern of the surface-emitting laser element array 52 and the rotation angle distribution in the phase modulation layer 65A. The diagram shows the relationship. Furthermore, the center Q of the output beam pattern is not limited to being located on an axis perpendicular to the main surface 53a of the semiconductor substrate 53; it can also be positioned on a vertical axis. For illustrative purposes, the center Q is set to be on an axis perpendicular to the main surface 53a. Figure 46 This shows the four quadrants with center Q as the origin. Figure 46 As an example, this illustrates a situation where optical images can be obtained in the first and third quadrants, but images can also be obtained in the second and fourth quadrants or all quadrants. In this variant example, as... Figure 46As shown, an optical image that is point-symmetric about the origin can be obtained. Figure 46 As an example, we show the case where the letter "A" is obtained in the third quadrant and the pattern is obtained by rotating the letter "A" by 180° in the first quadrant. Furthermore, in the case of rotational symmetry of the optical image, the images are superimposed and observed as a single optical image.

[0192] The optical image of the output beam pattern of the surface-emitting laser element 52 in this modified example includes a diffraction grating pattern. Here, in order to obtain the desired optical image including the diffraction grating pattern, the rotation angle distribution of the differential refractive index region 65b of the phase modulation layer 65A is determined in the following order.

[0193] First, as a prerequisite, in an XYZ orthogonal coordinate system defined by the Z-axis aligned with the normal direction and the XY plane aligned with one surface of the phase modulation layer 65A containing multiple differential refractive index regions 65b and containing mutually orthogonal X and Y axes, a virtual square lattice is set on the XY plane, consisting of M1 (an integer greater than 1) × N1 (an integer greater than 1) unit structural regions R, each of which is square.

[0194] As a second prerequisite, such as Figure 47 As shown, in the XYZ orthogonal coordinate system, the coordinates (ξ,η,ζ) are relative to the length r of the radius vector, and the inclination angle θ from the Z-axis. tilt A specific rotation angle θ from the X-axis in the XY plane. rot Defined spherical coordinates (r, θ) rot ,θ tilt ), satisfying the relationships shown in equations (6) to (8) below. Furthermore, Figure 47 It is used to explain the relationship between spherical coordinates (r, θ) rot ,θt ilt A graph showing the coordinate transformation to the XYZ orthogonal coordinate system (ξ, η, ζ) represents an optical image on a predetermined plane in the XYZ orthogonal coordinate system, which is the real space. When the beam pattern, equivalent to the optical image output from the surface-emitting laser element 52, is set to be oriented at an angle θ... tilt and θ rot When a set of bright spots in a specified direction is formed, the angle θ tilt and θ rot Converted to: the standardized wavenumber specified by the following equation (9) corresponds to the coordinate value k on the Kx axis of the X-axis. x The standardized wavenumber, as defined by equation (10) below, corresponds to the coordinate value k on the Ky axis, which is perpendicular to the Y-axis and orthogonal to the Kx-axis. yThe normalized wavenumber means the wavenumber 2π / a, which corresponds to the grid spacing of a virtual square grid, is normalized to 1.0. In this case, within the wavenumber space defined by the Kx-axis and Ky-axis, a specific wavenumber range containing the beam pattern corresponding to the optical image is composed of M2 (an integer greater than or equal to 1) × N2 (an integer greater than or equal to 1) image regions FR, each of which is square. Furthermore, the integer M2 need not be the same as the integer M1. Similarly, the integer N2 need not be the same as the integer N1. Additionally, equations (9) and (10) are disclosed, for example, in the aforementioned Non-Patent Document 4.

[0195] ξ=r sinθ tilt cosθ rot ……(6)

[0196] η = r sinθ tilt sinθ rot ……(7)

[0197] ζ=r cosθ tilt ……(8)

[0198]

[0199]

[0200] a: Lattice constant of the virtual square lattice

[0201] λ: Oscillation wavelength of the surface-emitting laser element 52

[0202] As a third prerequisite, in wavenumber space, by using the coordinate components k along the Kx-axis direction... x (an integer greater than 0 and less than M²-1) and the coordinate component k along the Ky axis. y The image region FR(k) is specified by an integer greater than or equal to 0 and less than N²-1. x ,k y The complex amplitude F(x,y) obtained by performing a two-dimensional discrete Fourier inverse transform on the unit structural region R(x,y) in the XY plane, specified by the coordinate components x (0 or higher and M1-1 or lower) in the X-axis direction and y (0 or higher and N1-1 or lower), is given by the following equation (11), with j as the imaginary part. Furthermore, this complex amplitude F(x,y) is defined by the following equation (12) when the amplitude term is set to A(x,y) and the phase term is set to P(x,y). Additionally, as a fourth prerequisite, the unit structural region R(x,y) is defined by the s-axis and t-axis, which are parallel to the X-axis and Y-axis respectively and orthogonal to the lattice point O(x,y) at the center of the unit structural region R(x,y).

[0203]

[0204] F(x,y)=A(x,y)×exp[jP(x,y)]……(12)

[0205] Under the aforementioned first to fourth preconditions, the phase modulation layer 65A is configured to satisfy the following first and second conditions. Specifically, the first condition is that within each unit structure region R(x, y), the centroid G is configured in a state separated from the lattice point O(x, y). Furthermore, the second condition is that the length r2(x, y) of the line segment connecting the lattice point O(x, y) to the corresponding centroid G is set to a common value in each of the M1 × N1 unit structure regions R, and the angle between the line segment connecting the lattice point O(x, y) and the corresponding centroid G and the s-axis is... The corresponding differential refractive index region 65b is configured within the unit structure region R(x, y) in a manner that satisfies the following relationship.

[0206]

[0207] C: Proportional constant, e.g., 180° / π

[0208] B: Any constant, such as 0

[0209] As a method to obtain the intensity distribution and phase distribution from the complex amplitude distribution obtained through Fourier transform, for example, the intensity distribution I(x,y) can be calculated using the abs function of the numerical analysis software "MATLAB" from MathWorks, and the phase distribution P(x,y) can be calculated using the angle function of MATLAB.

[0210] Here, we explain how to obtain the rotation angle distribution from the Fourier transform results of the optical image. Furthermore, when determining the configuration of each differential refractive index region 65b, considerations should be taken when using a general discrete Fourier transform (or fast Fourier transform) for calculation. The optical image before the Fourier transform, such as... Figure 48 When the beam is divided into four quadrants A1, A2, A3, and A4 as shown in (a), the resulting beam pattern is: Figure 48 As in (b). That is, in Figure 48 In (b), in the first quadrant of the beam pattern, there appears to be... Figure 48 The pattern of (a) rotated 180 degrees in the first quadrant and Figure 48 The overlapping pattern of the pattern in the third quadrant of (a). In the second quadrant of the beam pattern, the pattern that will appear... Figure 48 The pattern in (a) rotated 180 degrees in the second quadrant and Figure 48 The overlapping pattern of the pattern in the fourth quadrant of (a). In the third quadrant of the beam pattern, the pattern will appear... Figure 48The pattern in (a) rotated 180 degrees in the third quadrant and Figure 48 The pattern of (a) is an overlapping pattern in the first quadrant. In the fourth quadrant of the beam pattern, a pattern that will appear... Figure 48 The pattern in (a) rotated 180 degrees in the fourth quadrant and Figure 48 The overlapping pattern of the pattern in the second quadrant of (a).

[0211] Therefore, when an optical image with values ​​only in the first quadrant is used as the optical image before Fourier transform (the original optical image), the original optical image appears in the third quadrant of the resulting beam pattern, and a pattern in the first quadrant of the resulting beam pattern appears by rotating the first quadrant of the original optical image by 180 degrees.

[0212] As described above, in the surface-emitting laser element 52, a desired beam pattern can be obtained by phase modulation of the wavefront. This beam pattern is not only a pair of single-peak beams (points), but can also be, for example, a... Figures 9-12 The diffraction grating pattern shown.

[0213] In this modified example, the laser emitted from the active layer 62 is enclosed between the cladding layers 61 and 63 and enters the interior of the phase modulation layer 65A, forming a predetermined pattern corresponding to the lattice structure inside the phase modulation layer 65A. The laser light scattered within the phase modulation layer 65A is emitted outward from the back surface 53b of the semiconductor substrate 53. At this time, the 0th order light is emitted in a direction perpendicular to the main surface 53a. In contrast, the +1 and -1 order lights are emitted in arbitrary two-dimensional directions, including the direction perpendicular to the main surface 53a and the direction tilted towards it.

[0214] Furthermore, in the above description of this modified example, the wavelength λ0 is set to λ0 = a × n (where a is the lattice spacing), utilizing the band end Γ2, which is called a square lattice. On the other hand, the lattice spacing a can also be set as λ0 = (√2)a × n. This corresponds to the band end called point M of the square lattice. In this case, the phase angle distribution corresponding to the designed beam pattern... The additional phase angle distribution The phase is set to an overlapping phase angle distribution. Figure 49 It conceptually illustrates the distribution of rotation angles. An example diagram. For example... Figure 49 As shown, in this example, the first phase value and the first phase value Second phase value of different values Arranged in a checkered pattern. In one embodiment, the phase value... The phase value is 0 (rad). It is π (rad). That is, the first phase value. Second phase value The beam pattern varies with π. In this case, the design beam pattern can be extracted in the direction perpendicular to the surface, and the zero-order light can be eliminated in the direction perpendicular to the surface, with only the design beam pattern composed of ±1-order light emanating. The zero-order light is a wavefront without phase modulation, while the ±1-order light is a wavefront with phase modulation. Therefore, the spatial phase distribution of the addressing light E2 incident on the spatial light modulator 3 can be effectively controlled.

[0215] In this modified example, the light-emitting portion of the diffraction grating pattern of the output addressing beam E2 can also be constructed using an S-iPM laser. Even in this case, the same effect as in the above-described embodiment can be achieved. Furthermore, in this modified example, the resolution can be easily improved by arranging multiple S-iPM lasers and using them simultaneously. That is, in order to improve the resolution of a single S-iPM laser, it is necessary to increase the oscillation region size of the phase modulation layer 65A, but if the oscillation region size is increased, it may be difficult to maintain overall uniformity and stability. In this modified example, the phase control of the spatial light modulator 3 is performed using only the intensity information of the beam pattern output from the S-iPM laser, thereby allowing for the simple arrangement of multiple S-iPM lasers whose phases are not integrated with each other.

[0216] For example, the S-iPM laser described in Non-Patent Document 5 outputs a two-dimensional beam pattern with a resolution of 1400 rows and 1400 columns from an oscillation region of a square with a side width of 400 μm. When the light modulation region of the spatial light modulator 3 is set to a square with a side width of 50 cm, the number of pixels is 500,000 in both the row and column directions when pixels are arranged at 1 μm intervals. Alternatively, 357 S-iPM lasers with the aforementioned resolution can be arranged in both the row and column directions. Ideally, this results in a square with a side width of 14.3 cm. That is, by simply rotating an S-iPM laser array with a side width of 14.3 cm, the same function as rotating a hologram with a side width of 50 cm can be achieved, and a larger scale can be realized. In other words, by simply rotating an S-iPM laser array with a side width of 30 cm, the same function as rotating a hologram with a side width of 105 cm can be achieved, and a larger scale of over 1 m can be realized for stereoscopic images.

[0217] Furthermore, since the diffraction grating pattern is a simple repetition of a fringe pattern, it is not necessarily necessary to arrange the aforementioned number of S-iPM lasers. For example, an optical system including a beam splitter can be used to branch and transform the output pattern from a small number of S-iPM lasers. In this case, the number of S-iPM lasers can be reduced by the number of branches.

[0218] In addition, Figure 42 In the example shown, instead of a mechanically rotating array of surface-emitting laser elements 50, multiple arrays of surface-emitting laser elements 50 corresponding to multiple rotational phases can be switched and used. Alternatively, instead of an S-iPM laser, a D-iPM (Dynamic-integrable Phase Modulating) laser capable of dynamically changing the beam pattern can be used. In this case, the mechanical drive unit can be eliminated, thereby improving reliability. Furthermore, when using a D-iPM laser, since the phase control of the spatial light modulator 3 is performed using only the intensity information of the beam pattern, it is sufficient to simply arrange multiple D-iPM lasers whose phases are not integrated with each other.

[0219] In addition, in this modified example, the addressing light E2 from the surface-emitting laser element array 50 directly illuminates the back surface 3b of the spatial light modulator 3 without passing through the lens optical system. In order to form a finer diffraction grating pattern, a zoom lens optical system composed of multiple lenses can also be placed between the surface-emitting laser element array 50 and the back surface 3b.

[0220] (Sixth variation)

[0221] The S-iPM laser is not limited to the structure of the fifth variation described above. For example, even the structure of the phase modulation layer in this variation can be appropriately implemented as an S-iPM laser. Figure 50 This is a top view of the phase modulation layer 65B with an S-iPM laser. Additionally, Figure 51 This is a diagram showing the positional relationship of the differential refractive index region 65b in the phase modulation layer 65B. The phase modulation layer 65B is the resonant mode forming layer in this modified example. Figure 50 and Figure 51As shown, in the unit structure region R(x, y) of the phase modulation layer 65B, the centroid G of each differential refractive index region 65b is positioned on a straight line D. Straight line D passes through the lattice point O(x, y) of the unit structure region R(x, y) and is inclined relative to the sides of the square lattice. In other words, straight line D is inclined relative to both the X-axis and the Y-axis. The inclination angle of straight line D relative to one side (X-axis) of the square lattice is α. The inclination angle α is constant within the phase modulation layer 65B. The inclination angle α satisfies 0° < α < 90°, in one example α = 45°. Alternatively, the inclination angle α satisfies 180° < α < 270°, in one example α = 225°. When the inclination angle α satisfies 0° < α < 90° or 180° < α < 270°, straight line D extends from the first quadrant of the coordinate plane defined by the X and Y axes across the third quadrant. Alternatively, the tilt angle α satisfies 90° < α < 180°, in one example α = 135°. Or, the tilt angle α satisfies 270° < α < 360°, in one example α = 315°. When the tilt angle α satisfies 90° < α < 180° or 270° < α < 360°, the line D extends from the second quadrant across the fourth quadrant of the coordinate plane defined by the X and Y axes. As mentioned above, the tilt angle α is an angle other than 0°, 90°, 180°, and 270°. By setting the tilt angle α in this way, it is helpful to control both the output light beam, the light wave traveling along the X-axis, and the light wave traveling along the Y-axis. Here, the distance between the grid point O(x, y) and the centroid G is r(x, y). The component x represents the position of the x-th grid point on the X-axis, and the component y represents the position of the y-th grid point on the Y-axis. When the distance r(x, y) is positive, the centroid G is located in the first quadrant (or the second quadrant). When the distance r(x, y) is negative, the centroid G is located in the third quadrant (or fourth quadrant). When the distance r(x, y) is 0, the lattice point O and the centroid G are aligned.

[0222] The position of the unit structure region R(x, y) is assigned by an orthogonal coordinate system with the lattice point O(x, y) as the origin (defined by the s-axis parallel to the X-axis and the t-axis parallel to the Y-axis). Figure 51 The distance r(x, y) between the centroid G of each region 65b with different refractive indices and the lattice point O(x, y) of the unit structure region R(x, y) is individually set for each region 65b with a different refractive index, based on the desired optical image. The distribution of distance r(x, y) has a specific value for each position determined by the values ​​of x and y, but is not necessarily limited to being expressed by a specific function. The distribution of distance r(x, y) is determined by extracting the phase distribution from the complex amplitude distribution obtained by the inverse Fourier transform of the desired optical image. That is, in Figure 51When the phase P(x, y) of a certain coordinate (x, y) is P0, the distance r(x, y) is set to 0; when the phase P(x, y) is π+P0, the distance r(x, y) is set to the maximum value r0; and when the phase P(x, y) is -π+P0, the distance r(x, y) is set to the minimum value -r0. Furthermore, the intermediate phase P(x, y) is set as the distance r(x, y) in the manner r(x, y) = {P(x, y) - P0} × r0 / π. Here, the initial phase P0 can be arbitrarily set. When the grid spacing of the square is set to a, the maximum value r0 of r(x, y) is, for example, within the range shown in the following equation (13):

[0223]

[0224] As in this variation, the surface-emitting laser element array 50 may also have a phase modulation layer 65B as a resonant mode forming layer. In this case, a portion of the laser light generated by the phase modulation layer 65B (a portion of the +1st order light and -1st order light, and the 0th order light) diffracts in a direction that is not parallel to the main surface 53a of the semiconductor substrate 53. After being reflected by the metal electrode film 66 (or directly), it reaches the back surface 53b of the semiconductor substrate 53 and is emitted as addressing light E2 from the back surface 53b toward the spatial light modulator 3. In this variation, the surface-emitting laser element array 50 can image the addressing light E2, which includes a diffraction grating pattern, on the back surface 3b of the spatial light modulator 3. Therefore, the same effects as in the above-described embodiment can be achieved.

[0225] (Seventh variation)

[0226] In the above embodiment, a liquid crystal type is shown as the spatial light modulator 3, but the structure of the spatial light modulator is not limited to the liquid crystal type. Figure 52This is a top view showing the structure of a reflective dynamic metasurface (hereinafter referred to as a metasurface) 7A, another example of a spatial light modulator. A "metasurface" refers to a surface where multiple unit structures, sufficiently small compared to the wavelength of light E1, are arranged on a flat surface, causing a phase change in the incident light for each unit structure. Various structures exist for metasurfaces; the metasurface of this embodiment also has a structure called a gap-plasma type. The metasurface 7A is a flat plate extending along mutually intersecting (e.g., orthogonal) directions D1 and D2, with direction D3, which intersects (e.g., orthogonal) both directions D1 and D2, designated as the thickness direction. Multiple pixels 70 are formed on the main surface 7a of the metasurface 7A. The multiple pixels 70 are arranged in a two-dimensional configuration, with direction D1 as the row direction and direction D2 as the column direction. The planar shape of each pixel 70 is rectangular (e.g., square). The length L of one side of each pixel 70 is, for example, in the range of 200 nm to 400 nm. The metasurface 7A acts as a diffraction grating by individually modulating the phase of the light E1 input to the main surface 7a for each pixel 70.

[0227] Figure 53 It is along Figure 52 The cross-sectional view along line III-III shows the cross-sectional structure of the metasurface 7A. The metasurface 7A reflects light E1 containing a two-dimensional optical image illuminating the main surface 7a, and modulates the phase of light E1 for each of a plurality of pixels 70 arranged in a two-dimensional configuration. Each pixel 70 of the metasurface 7A has a structure that changes the amount of phase modulation according to the intensity of the addressing light E2 illuminating each pixel 70 from the back surface 7b. (See diagram below.) Figure 53 As shown, the metasurface 7A has: a transparent substrate 71, a transparent electrode layer 72, an impedance change layer 73A, a metal film 74, a stacked structure 75, a metal film 76, and a transparent substrate 77.

[0228] The transparent substrate 71 is a plate-shaped component with light transmittance. Here, light transmittance refers to the property of transmitting addressing light E2. In one example, the transparent substrate 71 is a glass substrate. The transparent substrate 71 includes a main surface 71a and a back surface 71b that are parallel to each other and face opposite directions. The main surface 71a and the back surface 71b are flat and smooth surfaces. The back surface 71b coincides with the back surface 7b of the metasurface 7A. The thickness of the transparent substrate 71 is, for example, more than 20 μm and less than 1 mm.

[0229] The transparent electrode layer 72 is located between the impedance changing layer 73A and the transparent substrate 71. Figure 53In the example shown, the transparent electrode layer 72 is in contact with the main surface 71a of the transparent substrate 71. The transparent electrode layer 72, like the transparent substrate 71, has light transmittance. That is, the transparent electrode layer 72 transmits addressing light E2. The constituent material of the transparent electrode layer 72 includes at least one of, for example, ITO or zinc oxide-based conductive materials (AZO, GZO). The thickness of the transparent electrode layer 72 is, for example, 1 nm or more and 1 μm or less. The transparent electrode layer 72 is not divided for each pixel, but is integrally disposed across the entire surface of the main surface 71a.

[0230] The impedance variation layer 73A is a semiconductor layer located between the metal film 74 and the transparent electrode layer 72. The impedance variation layer 73A exhibits an impedance distribution based on the intensity distribution of the addressing light E2. Specifically, the impedance of the material constituting the impedance variation layer 73A changes monotonically according to the light intensity when light is received. Examples of such materials include hydrogenated amorphous silicon, GaN-based compounds, InP-based compounds, and GaAs-based compounds. Therefore, the impedance variation layer 73A of this modified example can be composed of at least one of hydrogenated amorphous silicon, GaN-based compounds (e.g., i-type GaN), InP-based compounds (e.g., i-type InP), and GaAs-based compounds (e.g., i-type GaAs). The thickness of the impedance variation layer 73A is, for example, 10 nm to 20 μm. The impedance variation layer 73A is not divided for each pixel 70, but is integrally disposed across the entire surface of the main surface 71a.

[0231] The stacked structure 75 is a flat film extending across multiple pixels 70 along directions D1 and D2. The stacked structure 75 has a main surface 75a and a back surface 75b. Light E1 is input to the main surface 75a. The main surface 75a and the back surface 75b are opposite each other in direction D3. The spacing between the main surface 75a and the back surface 75b (i.e., the thickness of the stacked structure 75 in direction D3) is set to be sufficiently small compared to the wavelength λ of E1. The thickness of the stacked structure 75 is, for example, in the range of 10 nm to 100 nm. The stacked structure 75 has a transparent conductive layer 751 and a dielectric layer 752 stacked in direction D3 as the stacking direction.

[0232] The transparent conductive layer 751 is an inorganic film with both light transmittance and conductivity. Here, light transmittance refers to the property of transmitting light E1. Furthermore, conductivity refers to extremely low resistivity (e.g., an impedance of 10⁻⁶). -6 The properties are below Ω·m. The transparent electrode layer 751 of this modified example contains at least one of, for example, ITO, or a zinc oxide-based conductive material (AZO, GZO). The thickness of the transparent conductive layer 751 is, for example, in the range of 3 nm to 50 nm, and in one example, is 20 nm.

[0233] The dielectric layer 752 is an inorganic film with light transmittance and insulating properties. Insulation refers to extremely high resistivity (e.g., an impedance of 10⁻⁶). 6 The dielectric layer 752 contains at least one of, for example, aluminum oxide (Al₂O₃), silicon oxide (SiO₂), and magnesium fluoride (MgF₂). The thickness of the dielectric layer 752 is, for example, in the range of 1 nm to 20 nm, and in one example, is 5 nm. Furthermore, in… Figure 53 In the example shown, a transparent conductive layer 751 is provided on the back side 7b and a dielectric layer 752 is provided on the main side 7a. Alternatively, a transparent conductive layer 751 can be provided on the main side 7a and a dielectric layer 752 can be provided on the back side 7b.

[0234] The metal film 76 functions as a nanoantenna on a metasurface structure. The metal film 76 is disposed on the main surface 75a of the stacked structure 75. The metal film 76 is made of a metal such as gold (Au). The thickness of the metal film 76 is, for example, in the range of 30 nm to 100 nm, and in one example, is 50 nm. The metal film 76 divides each pixel 70. The width of the metal film 76 for each pixel 70 in direction D1 is set to be smaller than the length (pixel pitch) of the pixel 70 in the same direction, and is set to be sufficiently small compared to the wavelength λ of light E1. In one example, the width of the metal film 76 for each pixel 70 is in the range of 40 nm to 360 nm, and in one example, is 250 nm. Furthermore, the spacing between adjacent metal films 76 is in the range of 40 nm to 360 nm, and in one example, is 150 nm. Furthermore, the ratio (W1 / λ) of the width W1 of the metal film 76 to the wavelength λ of the light E1 is in the range of 0.02 to 1. Additionally, the ratio (W1 / L) of the width W1 of the metal film 76 to the length L of one side of the pixel 70 is in the range of 0.1 to 0.9.

[0235] A metal film 74 is disposed on the back surface 75b of the laminated structure 75, located between the laminated structure 75 and the impedance variation layer 73A. In one example, the metal film 74 is in contact with the back surface 75b. The metal film 74 reflects the light E1 input to the laminated structure 75 toward the main surface 7a. The metal film 74 is made of a metal such as gold (Au). The thickness of the metal film 74 is, for example, in the range of 100nm to 200nm, and in one example, is 150nm. The metal film 74 divides each pixel 70. In one example, the width of the metal film 74 for each pixel 70 is in the range of 40nm to 360nm. In addition, the ratio (W2 / L) of the width W2 of the metal film 74 for each pixel 70 to the length L of one side of the pixel 70 is in the range of 0.1 to 0.9.

[0236] A transparent substrate 77 is disposed on the main surface 75a of the laminated structure 75, with a metal film 76 covering it. In other words, the metal film 76 is disposed between the laminated structure 75 and the transparent substrate 77. The transparent substrate 77 is a plate-shaped component with light transmittance. Here, light transmittance refers to the property of transmitting light E1. In one example, the transparent substrate 77 is a glass substrate. The transparent substrate 77 includes a surface 77a on the side opposite to the laminated structure 75. The surface 77a is a flat and smooth surface and coincides with the main surface 7a of the metasurface 7A. The thickness of the transparent substrate 77 is, for example, more than 20 μm and less than 1 mm.

[0237] The effects obtained by the metasurface 7A having the above structure will be explained. The metasurface 7A has a MIM structure consisting of a metal film 74 serving as a light-reflecting film, a stacked structure 75 comprising a transparent conductive layer 751 and a dielectric layer 752, and a metal film 76 serving as a nanoantenna, stacked sequentially. In this case, light E1 incident on the main surface 7a of the metasurface 7A is incident on the exposed portion of the stacked structure 75 on one side of the metal film 76. This light E1 is guided between the metal films 74 and 76, and output from the exposed portion of the stacked structure 75 to the outside of the metasurface 7A via the main surface 7a on the other side of the metal film 76. At this time, when a driving voltage is applied between the metal films 76 and 74, induced currents in opposite directions, called gap surface plasmon modes, are generated in both metal films 76 and 74, and a strong magnetic resonance (plasma resonance) is generated within the stacked structure 75. By utilizing this magnetic resonance, the phase of the light E1 passing between the metal films 76 and 74 can be modulated.

[0238] Here, the following equation (14) represents the phase modulation amount of the light E1 transmitted through magnetic resonance. The width w (=W1) of the metal film 76, the wavelength λ of light E1, and the effective refractive index N of the stacked structure 75. gsp The relationship is as follows. Furthermore, m is an integer.

[0239]

[0240] It is evident from the above equation (14) that the phase modulation amount Depends on the effective refractive index N of the stacked structure 75 gsp Furthermore, the effective refractive index N can be controlled by changing the driving voltage applied between metal film 76 and metal film 74. gsp The reason is as follows. When a driving voltage is applied between metal film 76 and metal film 74, the electron density near the interface between transparent conductive layer 751 and dielectric layer 752 is high due to the electric field between them. As a result, as... Figure 53As shown, the portion near the interface of the transparent conductive layer 751 effectively transforms into a metallized layer 751a. Based on this layer 751a, the effective refractive index N of the stacked structure 75 relative to light E1... gsp Significant changes.

[0241] In this modified example, an AC voltage source 78 is electrically connected between the metal film 76 and the transparent electrode layer 72, and an AC driving voltage is applied between the metal film 76 and the transparent electrode layer 72. The effective voltage of the AC voltage is, for example, several volts, and the frequency is, for example, DC to 1 GHz. Furthermore, an impedance variation layer 73A is provided between the transparent electrode layer 72 and the metal film 74. When the addressing light E2 illuminates the back surface 3b side, the addressing light E2 reaches the impedance variation layer 73A and imparts an impedance distribution to the impedance variation layer 73A. That is, in pixels 70 with low light intensity of the addressing light E2, the impedance of the impedance variation layer 73A remains high; in pixels 70 with high light intensity of the addressing light E2, the impedance of the impedance variation layer 73A decreases. Figure 53 Region 73a). Therefore, the impedance distribution of the impedance change layer 73A becomes a distribution corresponding to the intensity distribution of the addressing light E2. In pixels 70 where the impedance of the impedance change layer 73A decreases, the voltage applied to the transparent conductive layer 751 increases, and a strong electric field is applied to the transparent conductive layer 751. Conversely, in pixels where the impedance of the impedance change layer 73A remains high, since the impedance of the impedance change layer 73A is at the same level as the impedance of the transparent conductive layer 751, the voltage applied to the transparent conductive layer 751 is low, and a weak electric field (or no electric field at all) is applied to the transparent conductive layer 751. Therefore, for light E1, a phase distribution corresponding to the light intensity distribution of the addressing light E2 is given. Furthermore, the addressing light E2 is blocked by the metal film 74 and does not reach the stacked structure 75.

[0242] As described above, since each pixel 70 of the metasurface 7A has a structure that changes the phase modulation amount according to the intensity of the addressing light E2 illuminating the back surface 7b of each pixel 70, the metasurface 7A imparts a phase pattern corresponding to the diffraction grating pattern to the light E1 incident on the main surface 7a. Therefore, when the two-dimensional optical image illuminating the main surface 7a is reflected by the metasurface 7A, it is deflected and output in a direction corresponding to the direction of the diffraction grating pattern. In addition, since the direction of the diffraction grating pattern on the back surface 7b also changes dynamically in this modified example as in the above embodiment, the deflection direction of the two-dimensional optical image also changes dynamically. When a two-dimensional optical image corresponding to the direction of the diffraction grating pattern is illuminating the main surface 7a, a three-dimensional image can be presented to the observer A. Furthermore, according to this image output device, by dynamically changing the addressing light E2 containing the diffraction grating pattern to output a three-dimensional image, the metasurface 7A, as a light deflection element, can be kept stationary while outputting a three-dimensional image. Therefore, compared to the device disclosed in Non-Patent Document 1, which mechanically rotates the holographic screen at high speed, the size of the metasurface 7A can be easily increased and the stereoscopic image magnified. Furthermore, as in this modified example, by using the metasurface 7A in a spatial light modulator, higher speed operation can be achieved compared to using a liquid crystal-type spatial light modulator.

[0243] In this modified example, the diffraction grating pattern can also be rotated on the back surface 7b of the metasurface 7A. In this case, a three-dimensional image can be presented over the entire 360° circumferential direction. Furthermore, the dynamic change in the orientation of the diffraction grating pattern is not limited to the rotation of the diffraction grating pattern, but can also be a rotation operation within a limited angular range.

[0244] As in this modified example, the metasurface 7A may also include: a metal film 74 located between the main surface 7a and the back surface 7b; a transparent conductive layer 751 located between the metal film 74 and the main surface 7a; a metal film 76 located between the transparent conductive layer 751 and the main surface 7a, serving as a nanoantenna; an impedance variation layer 73A located between the metal film 74 and the back surface 7b, which reflects the impedance distribution according to the intensity distribution of the addressing light E2; and a transparent electrode layer 72 located between the impedance variation layer 73A and the back surface 7b. As described above, for example, by having this structure, the phase modulation amount of each pixel 70 on the metasurface 7A can be varied according to the intensity of the addressing light E2 illuminating the back surface 7b side of each pixel 70.

[0245] As in this modified example, the impedance changing layer 73A may also comprise at least one of hydrogenated amorphous silicon, GaN-based compounds, InP-based compounds, and GaAs-based compounds. The impedance of these materials changes upon receiving light. Therefore, in this case, an impedance changing layer 73A that reflects the impedance distribution according to the intensity distribution of the addressing light E2 can be appropriately realized.

[0246] Figure 54 This is a cross-sectional view showing another structure of the metasurface 7B as a seventh variation. The difference between metasurface 7B and metasurface 7A is that metasurface 7B has an impedance variation layer 73B instead of the aforementioned impedance variation layer 73A. In addition to the structure of metasurface 7A, metasurface 7B also has a transparent conductive layer 79.

[0247] Impedance variation layer 73B is located between metal film 74 and transparent electrode layer 72. Impedance variation layer 73B exhibits impedance distribution according to the intensity distribution of address light E2. Specifically, the impedance of the material constituting impedance variation layer 73B changes monotonically according to the light intensity when light is received. Examples of such materials include hydrogenated amorphous silicon, GaN-based compounds, InP-based compounds, and GaAs-based compounds. Therefore, the impedance variation layer 73B of this modified example can be composed of at least one of hydrogenated amorphous silicon, GaN-based compounds (e.g., i-type GaN), InP-based compounds (e.g., i-type InP), and GaAs-based compounds (e.g., i-type GaAs). The thickness of impedance variation layer 73B is, for example, 10 nm to 20 μm. Furthermore, to avoid electrical crosstalk caused by carrier diffusion between adjacent impedance variation layers 73B, a gap GA is provided between adjacent impedance variation layers 73B.

[0248] When the addressing light E2 illuminates the back side 3b, the impedance of that portion locally decreases. Therefore, the impedance distribution of the impedance variation layer 73B corresponds to the intensity distribution of the addressing light E2. In pixels 70 where the impedance of the impedance variation layer 73B decreases, a larger voltage is applied to the transparent conductive layer 751, resulting in a stronger electric field on the transparent conductive layer 751. Conversely, in pixels where the impedance of the impedance variation layer 73B remains high, since the impedance of the impedance variation layer 73B is greater than the impedance of the transparent conductive layer 751, a smaller voltage is applied to the transparent conductive layer 751, resulting in a weak electric field (or no electric field applied at all) on the transparent conductive layer 751. Furthermore, the addressing light E2 is blocked by the metal film 74 and does not reach the laminated structure 75.

[0249] The transparent conductive layer 79, like the transparent substrate 77, possesses light transmittance and conductivity. The transparent conductive layer 79 allows light E1 to pass through. The material constituting the transparent electrode layer 79 includes at least one of, for example, ITO or zinc oxide-based conductive materials (AZO, GZO). The thickness of the transparent electrode layer 79 is, for example, 1 nm to 1 μm. The transparent electrode layer 79 is not divided for each pixel, but is integrally disposed across the entire surface of the main surface 71a. The transparent conductive layer 79 is situated between the metal film 76 and the transparent substrate 77, and is electrically connected to the metal film 76. In one example, the transparent conductive layer 79 is in contact with the metal film 76. An AC voltage source 78 is electrically connected between the transparent electrode layer 72 and the transparent conductive layer 79, and applies an AC voltage between the transparent electrode layer 72 and the transparent conductive layer 79.

[0250] Even as a metasurface 7B with the structure described above, the same effect as the metasurface 7A described above can be obtained. Furthermore, as... Figure 54 In the example shown, the transparent electrode layer 72, the impedance variation layer 73B, and the stacked structure 75 divide each pixel 70, and the divided parts can also be separated from each other via gaps GA. This suppresses electrical crosstalk between adjacent pixels.

[0251] The image output device according to the present invention is not limited to the embodiments described above, and various other modifications can be realized. For example, as a spatial light modulator, a liquid crystal type spatial light modulator 3 is exemplified in the above embodiments, and metasurfaces 7A and 7B are exemplified in the seventh modification. However, the spatial light modulator applicable to the present invention is not limited to these, and various other structures can be applied. In addition, the structures of the addressing light irradiation unit and the image irradiation unit are not limited to the above embodiments and modifications, and various other structures can be applied.

[0252] It is evident from the above description of the present invention that various modifications can be made to the present invention. These modifications should not be considered as departing from the spirit and scope of the present invention, and all improvements that are self-evident to those skilled in the art are included within the scope of the following claims.

Claims

1. An image output apparatus, wherein provided with: a spatial light modulator having a main surface, a back surface opposite to the main surface, and a plurality of pixels arranged two-dimensionally along the main surface in a space between the main surface and the back surface, the spatial light modulator reflecting light irradiated on the main surface and modulating a phase of the light individually for the plurality of pixels; an image irradiation section irradiating a two-dimensional optical image toward the main surface; and an addressing light irradiation section irradiating addressing light containing a diffraction grating pattern toward the back surface, the plurality of pixels of the spatial light modulator are respectively configured in a manner that a phase modulation amount varies in accordance with an intensity of the addressing light irradiated from the back surface side, the addressing light irradiation section is configured in a manner that a direction of the diffraction grating pattern of the back surface of the spatial light modulator in a stationary state dynamically varies, the image irradiation section irradiates the two-dimensional optical image corresponding to the direction of the diffraction grating pattern toward the main surface.

2. The image output apparatus according to claim 1, wherein the addressing light irradiation section rotates the diffraction grating pattern on the back surface.

3. The image output apparatus according to claim 1, wherein the spatial light modulator has: a light reflection layer provided between the main surface and the back surface; a liquid crystal layer provided between the light reflection layer and the main surface; a light-transmissive first electrode layer provided between the liquid crystal layer and the main surface; an impedance variation layer provided between the light reflection layer and the back surface, embodying a distribution of impedance in accordance with an intensity distribution of the addressing light; and a light-transmissive second electrode layer provided between the impedance variation layer and the back surface, the liquid crystal layer has a plurality of partition walls dividing a liquid crystal region into divisions corresponding to the plurality of pixels individually.

4. The image output apparatus according to claim 2, wherein the spatial light modulator has: a light reflection layer provided between the main surface and the back surface; a liquid crystal layer provided between the light reflection layer and the main surface; a light-transmissive first electrode layer provided between the liquid crystal layer and the main surface; an impedance variation layer provided between the light reflection layer and the back surface, embodying a distribution of impedance in accordance with an intensity distribution of the addressing light; and a light-transmissive second electrode layer provided between the impedance variation layer and the back surface, the liquid crystal layer has a plurality of partition walls dividing a liquid crystal region into divisions corresponding to the plurality of pixels individually.

5. The image output apparatus according to claim 3, wherein the plurality of partition walls are two-dimensionally arranged along both a first direction on the main surface and a second direction on the main surface orthogonal to the first direction; a distance between adjacent partition walls arranged along the second direction is larger than a distance between adjacent partition walls arranged along the first direction.

6. The image output apparatus according to claim 4, wherein the plurality of partition walls are two-dimensionally arranged along both a first direction on the main surface and a second direction on the main surface orthogonal to the first direction; and a distance between adjacent partition walls arranged along the second direction is larger than a distance between adjacent partition walls arranged along the first direction. ​ ​ The adjacent partition walls arranged in the second direction are spaced apart from each other by a distance greater than the distance between the adjacent partition walls arranged in the first direction.

7. The image output device according to claim 5, wherein The adjacent partition walls arranged in the second direction are spaced apart from each other by a distance twice or more the distance between the adjacent partition walls arranged in the first direction.

8. The image output device according to claim 6, wherein The adjacent partition walls arranged in the second direction are spaced apart from each other by a distance twice or more the distance between the adjacent partition walls arranged in the first direction.

9. The image output device according to claim 3, wherein The plurality of partition walls are arranged two-dimensionally in both a first direction on the main surface and a second direction on the main surface orthogonal to the first direction, The adjacent partition walls arranged in the first direction are spaced apart from each other by a distance of 5 μm or less, and the partition walls arranged in the second direction are spaced apart from each other by a distance of 5 μm or less.

10. The image output device according to claim 4, wherein The plurality of partition walls are arranged two-dimensionally in both a first direction on the main surface and a second direction on the main surface orthogonal to the first direction, The adjacent partition walls arranged in the first direction are spaced apart from each other by a distance of 5 μm or less, and the partition walls arranged in the second direction are spaced apart from each other by a distance of 5 μm or less.

11. The image output device according to claim 3, wherein The impedance change layer contains at least one of hydrogenated amorphous silicon, a GaN-based compound, an InP-based compound, and a GaAs-based compound.

12. The image output device according to claim 4, wherein The impedance change layer contains at least one of hydrogenated amorphous silicon, a GaN-based compound, an InP-based compound, and a GaAs-based compound.

13. The image output device according to claim 5, wherein The impedance change layer contains at least one of hydrogenated amorphous silicon, a GaN-based compound, an InP-based compound, and a GaAs-based compound.

14. The image output device according to claim 6, wherein The impedance change layer contains at least one of hydrogenated amorphous silicon, a GaN-based compound, an InP-based compound, and a GaAs-based compound.

15. The image output device according to claim 7, wherein The impedance change layer contains at least one of hydrogenated amorphous silicon, a GaN-based compound, an InP-based compound, and a GaAs-based compound.

16. The image output device according to claim 8, wherein The impedance change layer contains at least one of hydrogenated amorphous silicon, a GaN-based compound, an InP-based compound, and a GaAs-based compound.

17. The image output device according to claim 9, wherein The impedance change layer contains at least one of hydrogenated amorphous silicon, a GaN-based compound, an InP-based compound, and a GaAs-based compound.

18. The image output device according to claim 10, wherein The impedance change layer contains at least one of hydrogenated amorphous silicon, a GaN-based compound, an InP-based compound, and a GaAs-based compound.

19. The image output device according to claim 1, wherein provided with: a laminated structure having a first surface, a second surface opposite to the first surface, a transparent conductive layer provided between the first surface and the second surface, and a dielectric layer provided between the first surface and the second surface, and inputted with the two-dimensional optical image at the first surface; a first metal film provided at the first surface of the laminated structure; a second metal film provided at the second surface of the laminated structure, and reflecting the two-dimensional optical image inputted to the laminated structure toward the first surface; an impedance change layer provided at the opposite side of the laminated structure with respect to the second metal film, and embodying a distribution of impedance according to the intensity distribution of the addressing light; and an electrode layer provided at the opposite side of the second metal film with respect to the impedance change layer, any one of the first metal film and the second metal film each corresponds to the plurality of pixels, and is constituted by a plurality of partial metal films separated from each other, and a part of the laminated structure is exposed between the plurality of partial metal films constituting the first metal film as viewed in a laminating direction.

20. The image output device according to claim 2, wherein provided with: a laminated structure having a first surface, a second surface opposite to the first surface, a transparent conductive layer provided between the first surface and the second surface, and a dielectric layer provided between the first surface and the second surface, and inputted with the two-dimensional optical image at the first surface; a first metal film provided at the first surface of the laminated structure; a second metal film provided at the second surface of the laminated structure, and reflecting the two-dimensional optical image inputted to the laminated structure toward the first surface; an impedance change layer provided at the opposite side of the laminated structure with respect to the second metal film, and embodying a distribution of impedance according to the intensity distribution of the addressing light; and an electrode layer provided at the opposite side of the second metal film with respect to the impedance change layer, any one of the first metal film and the second metal film each corresponds to the plurality of pixels, and is constituted by a plurality of partial metal films separated from each other, and a part of the laminated structure is exposed between the plurality of partial metal films constituting the first metal film as viewed in a laminating direction.

21. The image output device according to any one of claims 1 to 20, wherein the addressing light irradiation section has: a light emitting section outputting the addressing light containing the diffraction grating pattern; and a driving section dynamically changing a posture angle around an optical axis of the light emitting section.

22. The image output device according to any one of claims 1 to 20, wherein the addressing light irradiation section has: a plurality of light emitting sections arranged along a circumference, and outputting the addressing light containing the diffraction grating pattern; and an optical system optically coupling the plurality of light emitting sections and the back surface, ​ The addressing light from the light emitting section selected from the plurality of light emitting sections corresponding to the direction of the diffraction grating pattern is input to the back surface.

23. The image output device according to claim 22, wherein The optical system includes a superlens.

24. The image output device according to any one of claims 1 to 20, wherein The addressing light irradiation section has a light emitting section disposed along a circumference and outputs the addressing light including the diffraction grating pattern having a radial direction of the circumference as a periodic direction, The light emitting section is a plurality of element electrodes arranged in a circumferential direction of the circumference, and an element electrode of the plurality of element electrodes corresponding to the direction of the diffraction grating pattern selectively emits the addressing light.

25. The image output device according to claim 21, wherein The light emitting section includes a plurality of light emitting regions arranged based on the diffraction grating pattern.

26. The image output device according to claim 22, wherein The light emitting section includes a plurality of light emitting regions arranged based on the diffraction grating pattern.

27. The image output device according to claim 23, wherein The light emitting section includes a plurality of light emitting regions arranged based on the diffraction grating pattern.

28. The image output device according to claim 24, wherein The light emitting section includes a plurality of light emitting regions arranged based on the diffraction grating pattern.

29. The image output device according to claim 21, wherein The light emitting section includes a surface-emitting laser element having an active layer and a phase modulation layer; The phase modulation layer includes a base layer and a plurality of difference refractive index regions having a refractive index different from that of the base layer and distributed two-dimensionally on a surface perpendicular to a thickness direction of the phase modulation layer, In a virtual square lattice set on the surface of the phase modulation layer, a barycenter of each of the plurality of difference refractive index regions is set in a first state defined by the barycenter of each of the plurality of difference refractive index regions being arranged apart from a corresponding lattice point of lattice points of the virtual square lattice and a rotation angle around the corresponding lattice point being individually set for each of the plurality of difference refractive index regions, or a second state defined by the barycenter of each of the plurality of difference refractive index regions being arranged on a straight line inclined with respect to the square lattice through the corresponding lattice point of the lattice points of the virtual square lattice and a distance of the barycenter of each of the plurality of difference refractive index regions from the corresponding lattice point being individually set.

30. The image output device according to claim 22, wherein The light emitting section includes a surface-emitting laser element having an active layer and a phase modulation layer; The phase modulation layer includes a base layer and a plurality of difference refractive index regions having a refractive index different from that of the base layer and distributed two-dimensionally on a surface perpendicular to a thickness direction of the phase modulation layer, In a virtual square lattice set on the face of the phase modulation layer, the center of gravity of each of the plurality of difference refractive index regions is set to a first state or a second state, the first state is defined by the center of gravity of each of the plurality of difference refractive index regions being disposed apart from a corresponding lattice point among lattice points of the virtual square lattice, and for each of the plurality of difference refractive index regions, a rotation angle around the corresponding lattice point is individually set, the second state is defined by the center of gravity of each of the plurality of difference refractive index regions being disposed on a straight line inclined with respect to the square lattice through the corresponding lattice point among the lattice points of the virtual square lattice, and a distance of the center of gravity of each of the plurality of difference refractive index regions from the corresponding lattice point is individually set.

31. The image output device according to claim 23, wherein the light emitting portion includes a surface-emission laser element having an active layer and a phase modulation layer; the phase modulation layer includes: a base layer; and a plurality of difference refractive index regions having a refractive index different from that of the base layer and distributed two-dimensionally on a face perpendicular to a thickness direction of the phase modulation layer, In a virtual square lattice set on the face of the phase modulation layer, the center of gravity of each of the plurality of difference refractive index regions is set to a first state or a second state, the first state is defined by the center of gravity of each of the plurality of difference refractive index regions being disposed apart from a corresponding lattice point among lattice points of the virtual square lattice, and for each of the plurality of difference refractive index regions, a rotation angle around the corresponding lattice point is individually set, the second state is defined by the center of gravity of each of the plurality of difference refractive index regions being disposed on a straight line inclined with respect to the square lattice through the corresponding lattice point among the lattice points of the virtual square lattice, and a distance of the center of gravity of each of the plurality of difference refractive index regions from the corresponding lattice point is individually set.

32. The image output device according to claim 24, wherein the light emitting portion includes a surface-emission laser element having an active layer and a phase modulation layer; the phase modulation layer includes: a base layer; and a plurality of difference refractive index regions having a refractive index different from that of the base layer and distributed two-dimensionally on a face perpendicular to a thickness direction of the phase modulation layer, In a virtual square lattice set on the face of the phase modulation layer, the center of gravity of each of the plurality of regions of different refractive index is set to a first state or a second state, the first state being defined by the center of gravity of each of the plurality of regions of different refractive index being disposed apart from a corresponding one of lattice points of the virtual square lattice, and the angle of rotation around the corresponding lattice point being individually set for each of the plurality of regions of different refractive index, the second state being defined by the center of gravity of each of the plurality of regions of different refractive index being disposed on a straight line inclined with respect to the square lattice through the corresponding one of lattice points of the virtual square lattice, and the distance of the center of gravity of each of the plurality of regions of different refractive index from the corresponding lattice point being individually set.

33. The image output device according to claim 21, wherein the light emitting section has: a photonic crystal surface-emission laser element having an active layer and a photonic crystal layer; and a periodic structure provided on a light exit surface of the photonic crystal surface-emission laser element and periodically provided with an opening portion and a light blocking portion according to the diffraction grating pattern.

34. The image output device according to claim 22, wherein the light emitting section has: a photonic crystal surface-emission laser element having an active layer and a photonic crystal layer; and a periodic structure provided on a light exit surface of the photonic crystal surface-emission laser element and periodically provided with an opening portion and a light blocking portion according to the diffraction grating pattern.

35. The image output device according to claim 23, wherein the light emitting section has: a photonic crystal surface-emission laser element having an active layer and a photonic crystal layer; and a periodic structure provided on a light exit surface of the photonic crystal surface-emission laser element and periodically provided with an opening portion and a light blocking portion according to the diffraction grating pattern.

36. The image output device according to claim 24, wherein the light emitting section has: a photonic crystal surface-emission laser element having an active layer and a photonic crystal layer; and a periodic structure provided on a light exit surface of the photonic crystal surface-emission laser element and periodically provided with an opening portion and a light blocking portion according to the diffraction grating pattern.

37. The image output device according to any one of claims 1 to 20, wherein the address light irradiation section has: a laser light source; a branching section that branches laser light output from the laser light source; and an interference optical system that causes one of the laser light branched by the branching section and the other laser light to interfere and generate an interference fringe, the interference optical system includes a position changing section that dynamically changes a relative positional relationship when the one laser light and the other laser light interfere, the interference fringe serves as the diffraction grating pattern.

38. The image output device according to any one of claims 1 to 20, wherein the diffraction grating pattern has a structure in which light intensity periodically changes in a certain direction, and the light intensity changes in a stage and monotonously strengthens or weakens within each period, the number of regions in which the light intensity differs from each other is three or more within each period.

39. The image output device according to any one of claims 1 to 20, wherein Further comprising a filter disposed between the image irradiation section and the spatial light modulator, which reduces the intensity of at least a portion of wavelength components other than visible light included in the two-dimensional optical image.

Images