Image display device, image display system, and projection optical system

Abstract

An image display device according to one embodiment of the present technology is provided with a light source, an image generation unit, and a projection optical system. The image generation unit modulates light emitted from the light source to generate image light including a plurality of pixel light beams. The projection optical system has a lens system and a reflecting optical system. The lens system is configured using a reference axis as a reference at a position where the generated image light is incident, and refracts and emits each of the plurality of pixel light beams included in the generated image light. The reflecting optical system is configured using the reference axis as a reference, and reflects, in the same traveling direction, the plurality of pixel light beams emitted from the lens system toward an object onto which the pixel light beams are projected.

Description

[Technical Field]

[0001] The present technology relates to an image display device such as a projector, an image display system, and a projection optical system. [Background technology]

[0002] Projectors have been widely known as projection-type image display devices that display images on a screen. Recently, there has been an increasing demand for ultra-wide-angle front-projectors that can display large images even in small projection spaces. By using these projectors, it is possible to project a large image in a limited space by projecting the image obliquely and at a wide angle onto the screen.

[0003] The ultra-wide-angle projection projector described in Patent Document 1 is capable of screen shifting, which moves the image projected onto the screen, by moving some of the optical components included in the projection optical system. Using this screen shifting makes it easy to fine-tune the image position, etc.

[0004] In the projection display device described in Patent Document 2, a light beam from a display panel is reflected by a plurality of rotationally asymmetric reflective surfaces and projected onto a screen. The image of the diaphragm is formed at a negative magnification by an optical system (a plurality of rotationally asymmetric reflective surfaces) located closer to the screen than the diaphragm position. This reduces the effective diameter of the light beam on each surface, thereby enabling the compactness of each optical element, such as the reflective surfaces, and the entire optical system.

[0005] Furthermore, a technique for projecting image light onto a transparent screen to display an image is also known in image display systems using a projector, etc. For example, by projecting image light onto a transparent screen through which the background, etc., can be seen, the image can be displayed so as to overlap with the background.

[0006] The image display device described in Patent Document 3 uses a transparent screen configured by combining two HOEs (Holographic Optical Elements). For example, a transparent screen is used in which a first HOE with a diffusion function and a second HOE with a concave mirror function are integrated together. This makes it possible to view a virtual image formed at a position different from the surface of the transparent screen, allowing users to enjoy a floating image display. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5365155 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-255462 [Patent Document 3] Japanese Patent Application Publication No. 2018-163307 Summary of the Invention [Problem to be solved by the invention]

[0008] 2. Description of the Related Art There is a demand for technology that can realize high-quality image display in image display devices such as projectors.

[0009] In view of the above circumstances, an object of the present technology is to provide an image display device and a projection optical system that can realize high-quality image display. [Means for solving the problem]

[0010] In order to achieve the above object, an image display device according to an embodiment of the present technology includes a light source, an image generation unit, and a projection optical system. The image generating section modulates the light emitted from the light source to generate image light including a plurality of pixel lights. The projection optical system includes a lens system and a reflection optical system. The lens system is configured with a reference axis as a reference at a position where the generated image light is incident, and refracts and emits each of the plurality of pixel lights included in the generated image light. The reflection optical system is configured with the reference axis as a reference, and reflects the pixel lights emitted from the lens system onto a projection target while aligning the directions of the light.

[0011] In this image display device, the light from multiple pixels that make up an image is refracted by a lens system and emitted to a reflective optical system, which aligns the direction of travel of the light from multiple pixels and reflects it off the projection target, thereby enabling high-quality image display.

[0012] The standard deviation of the distribution of the traveling directions of the pixel lights reflected by the reflection optical system may be smaller than 0.16.

[0013] The reflective optics may include one or more curved reflective surfaces having a rotationally asymmetric shape.

[0014] The one or more curved reflective surfaces may include a first reflective surface that reflects the plurality of pixel light beams emitted from the lens system, a second reflective surface that reflects the plurality of pixel light beams reflected by the first reflective surface, and a third reflective surface that reflects the plurality of pixel light beams reflected by the second reflective surface onto the projection object.

[0015] A standard deviation of the distribution of the traveling directions of the pixel light reflected by the third reflecting surface may be smaller than 0.16.

[0016] The image generation unit may emit the image light, which forms a rectangular image having a pair of opposing long sides and a pair of opposing short sides, to the lens system using the reference axis as a reference. In this case, if a direction corresponding to the direction of the short sides of the image of the image light emitted to the lens system is defined as a first direction and a direction corresponding to the direction of the long sides of the image of the image light emitted to the lens system is defined as a second direction, when the projection optical system is viewed along the first direction, the first reflecting surface may have negative power, the second reflecting surface may have negative power, and the third reflecting surface may have positive power. Furthermore, when the projection optical system is viewed along the second direction, the first reflecting surface may have positive power, the second reflecting surface may have negative power, and the third reflecting surface may have positive power.

[0017] When the projection optical system is viewed along the first direction, the pixel light corresponding to the pixel at the center of the short side of the image is defined as short side pixel light, and the angle between the short side pixel light incident on the third reflecting surface and the short side pixel light reflected by the third reflecting surface is defined as θLx. 0.25<θLx / 360<0.47 The relationship may be satisfied.

[0018] The one or more curved reflective surfaces may be a single curved reflective surface.

[0019] The standard deviation of the distribution of the traveling directions of the pixel light reflected by the one curved reflecting surface may be smaller than 0.13.

[0020] The image generation unit may emit the image light constituting a rectangular image having a pair of opposing long sides and a pair of opposing short sides to the lens system using the reference axis as a reference. In this case, if a direction corresponding to the direction of the short sides of the image of the image light emitted to the lens system is defined as a first direction and a direction corresponding to the direction of the long sides of the image of the image light emitted to the lens system is defined as a second direction, the one curved reflective surface may have positive power when the projection optical system is viewed along the first direction. Furthermore, the one curved reflective surface may have positive power when the projection optical system is viewed along the second direction.

[0021] When the projection optical system is viewed along the first direction, the pixel light corresponding to the pixel at the center of the short side of the image is defined as short side pixel light, and the angle between the short side pixel light incident on the one curved reflective surface and the short side pixel light reflected by the one curved reflective surface is defined as θLx, 0.02<θLx / 360<0.47 The relationship may be satisfied.

[0022] The image generation unit may emit the image light constituting a rectangular image having a pair of long sides facing each other and a pair of short sides facing each other to the lens system with the reference axis as a reference. In this case, a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, and a curved reflecting surface among the one or more curved reflecting surfaces that reflects the plurality of pixel lights to the projection target is defined as a final reflecting surface, When the projection optical system is viewed along the second direction, the pixel light corresponding to the pixel at the center of one long side of the image is defined as a first long side pixel light, the pixel light corresponding to the pixel at the center of the other long side of the image is defined as a second long side pixel light, and the angle between the first long side pixel light incident on the final reflection surface and the first long side pixel light reflected by the final reflection surface is defined as θa1, and the angle between the second long side pixel light incident on the final reflection surface and the second long side pixel light reflected by the final reflection surface is defined as θa2, 0.35 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.96 The relationship may be satisfied.

[0023] The image generation unit may emit the image light constituting a rectangular image having a pair of long sides facing each other and a pair of short sides facing each other to the lens system with the reference axis as a reference. In this case, a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, and a curved reflecting surface among the one or more curved reflecting surfaces that reflects the plurality of pixel lights to the projection target is defined as a final reflecting surface, When the projection optical system is viewed along the second direction, the pixel light corresponding to the pixel at the center of one long side of the image is defined as a first long side pixel light, and the pixel light corresponding to the pixel at the center of the other long side of the image is defined as a second long side pixel light. If the intersection angle between the traveling direction of the first long side pixel light reflected by the final reflection surface and the traveling direction of the second long side pixel light reflected by the final reflection surface is defined as θLy, then: -0.1<θLy / 360<0.1 The relationship may be satisfied.

[0024] The image generation unit may emit the image light constituting a rectangular image having a pair of long sides facing each other and a pair of short sides facing each other to the lens system with the reference axis as a reference. In this case, a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, and a curved reflecting surface among the one or more curved reflecting surfaces that reflects the plurality of pixel lights to the projection target is defined as a final reflecting surface, Among the one or more curved reflecting surfaces, the curved reflecting surface having the largest difference between the power when the projection optical system is viewed along the first direction and the power when the projection optical system is viewed along the second direction may be the final reflecting surface.

[0025] The image generating unit may emit the image light constituting a rectangular image having a pair of opposing long sides and a pair of opposing short sides to the lens system with the reference axis as a reference. In this case, the lens system may include an adjustment optical component that controls either an angle of view in the long side direction of the image or an angle of view in the short side direction of the image.

[0026] The adjustment optics may include a cylindrical lens.

[0027] The traveling direction of the plurality of pixel lights may be the traveling direction of a chief ray of each of the plurality of pixel lights.

[0028] An image display system according to one embodiment of the present technology includes a projection object and the image display device. The projection object displays an image by projecting image light including a plurality of pixel lights onto the projection object, and the projection object displays the image by controlling the traveling direction of the plurality of pixel lights incident thereon.

[0029] The projection object may be a hologram screen or a Fresnel lens screen.

[0030] A projection optical system according to one embodiment of the present technology is a projection optical system that projects image light including a plurality of pixel lights generated by modulating light emitted from a light source onto a projection target, and includes the lens system and the reflective optical system. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 10 is a schematic diagram for explaining another advantage of the super-wide-angle liquid crystal projector. [Figure 2] FIG. 10 is a schematic diagram showing an example of projecting an image onto a holographic screen. [Figure 3] 1 is a schematic diagram showing an example of the configuration of a projection-type image display device according to a first embodiment. [Figure 4] 1 is a schematic diagram illustrating an example of the configuration of an image display system according to a first embodiment. [Figure 5] 1 is a schematic diagram illustrating an example of the configuration of an image display system according to a first embodiment. [Figure 6] 1 is a schematic diagram illustrating an example of the configuration of an image display system according to a first embodiment. [Figure 7] 1 is a light path diagram showing a schematic configuration example of a projection optical system according to a first embodiment. [Figure 8] 1 is a light path diagram showing a schematic configuration example of a projection optical system according to a first embodiment. [Figure 9] 10 is a table showing an example of parameters related to image projection. [Figure 10] FIG. 10 is a schematic diagram for explaining parameters shown in FIG. [Figure 11] 10 is lens data of the image display device. [Figure 12] 1 is a table showing an example of aspherical coefficients of optical components included in a projection optical system; [Figure 13] 10A and 10B are diagrams for explaining evaluation of the traveling directions of a plurality of pixel lights reflected toward a screen. [Figure 14] 10 is a table showing evaluation results of the traveling directions of light from a plurality of pixels. [Figure 15] FIG. 2 is a schematic diagram showing parameters relating to characteristic points of a projection optical system. [Figure 16] FIG. 2 is a schematic diagram showing parameters relating to characteristic points of a projection optical system. [Figure 17] 17 is a table showing the values ​​of the parameters set in FIGS. 15 and 16. [Figure 18] FIG. 10 is a schematic diagram showing an example of distortion aberration of an image projected onto a holographic screen. [Figure 19] 10 is a graph showing an example of a lateral aberration diagram relating to a projected image. [Figure 20] FIG. 10 is a schematic diagram showing an example of the configuration of an image display system according to a second embodiment. [Figure 21] FIG. 10 is a schematic diagram showing an example of the configuration of an image display system according to a second embodiment. [Figure 22] FIG. 10 is a schematic diagram showing an example of the configuration of an image display system according to a second embodiment. [Figure 23] FIG. 10 is a light path diagram showing a schematic configuration example of a projection optical system according to a second embodiment. [Figure 24] FIG. 10 is a light path diagram showing a schematic configuration example of a projection optical system according to a second embodiment. [Figure 25] 10 is lens data of the image display device. [Figure 26] 1 is a table showing an example of aspherical coefficients of optical components included in a projection optical system; [Figure 27] FIG. 2 is a schematic diagram showing parameters relating to characteristic points of a projection optical system. [Figure 28] FIG. 2 is a schematic diagram showing parameters relating to characteristic points of a projection optical system. [Figure 29] 29 is a table showing the values ​​of the parameters set in FIGS. 27 and 28. [Figure 30] FIG. 10 is a schematic diagram showing an example of distortion aberration of an image projected onto a holographic screen. [Figure 31] 10 is a graph showing an example of a lateral aberration diagram relating to a projected image. [Figure 32] FIG. 10 is a schematic diagram showing an example of the configuration of an image display system according to a third embodiment. [Figure 33]FIG. 10 is a schematic diagram showing an example of the configuration of an image display system according to a third embodiment. [Figure 34] FIG. 10 is a schematic diagram showing an example of the configuration of an image display system according to a third embodiment. [Figure 35] FIG. 10 is a light path diagram showing a schematic configuration example of a projection optical system according to a third embodiment. [Figure 36] FIG. 10 is a light path diagram showing a schematic configuration example of a projection optical system according to a third embodiment. [Figure 37] 10 is lens data of the image display device. [Figure 38] 1 is a table showing an example of aspherical coefficients of optical components included in a projection optical system; [Figure 39] FIG. 2 is a schematic diagram showing parameters relating to characteristic points of a projection optical system. [Figure 40] FIG. 2 is a schematic diagram showing parameters relating to characteristic points of a projection optical system. [Figure 41] 39 and 38. FIG. 40 is a table showing the values ​​of the parameters set in FIG. [Figure 42] FIG. 10 is a schematic diagram showing an example of distortion aberration of an image projected onto a holographic screen. [Figure 43] 10 is a graph showing an example of a lateral aberration diagram relating to a projected image. [Figure 44] FIG. 10 is a schematic diagram showing an example of the configuration of an image display system according to a fourth embodiment. [Figure 45] FIG. 10 is a schematic diagram showing an example of the configuration of an image display system according to a fourth embodiment. [Figure 46] FIG. 10 is a schematic diagram showing an example of the configuration of an image display system according to a fourth embodiment. [Figure 47] FIG. 10 is a light path diagram showing a schematic configuration example of a projection optical system according to a fourth embodiment. [Figure 48] FIG. 10 is a light path diagram showing a schematic configuration example of a projection optical system according to a fourth embodiment. [Figure 49] 10 is a table showing an example of parameters related to image projection. [Figure 50] 10 is lens data of the image display device. [Figure 51]10 is lens data of the image display device. [Figure 52] 1 is a table showing an example of aspherical coefficients of optical components included in a projection optical system; [Figure 53] 1 is a table showing an example of aspherical coefficients of optical components included in a projection optical system; [Figure 54] 10 is a table showing evaluation results of the traveling directions of light from a plurality of pixels. [Figure 55] FIG. 2 is a schematic diagram showing parameters relating to characteristic points of a projection optical system. [Figure 56] FIG. 2 is a schematic diagram showing parameters relating to characteristic points of a projection optical system. [Figure 57] 57 is a table showing the numerical values ​​of the parameters set in FIGS. 55 and 56. [Figure 58] FIG. 10 is a schematic diagram showing an example of distortion aberration of an image projected onto a holographic screen. [Figure 59] 10 is a graph showing an example of a lateral aberration diagram relating to a projected image. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, embodiments of the present technology will be described with reference to the drawings.

[0033] [Projection-type image display device overview] The projection type image display device will be briefly outlined below, taking a liquid crystal projector as an example. A liquid crystal projector forms an optical image (image light) according to a video signal by spatially modulating light emitted from a light source. Light modulation is performed using image modulation elements such as liquid crystal display elements. For example, a three-panel liquid crystal projector is used, which has panel-shaped liquid crystal display elements (liquid crystal panels) corresponding to each of the RGB colors. The optical image is enlarged and projected by a projection optical system and displayed on a screen.

[0034] [Ultra-short throw projector] For example, if a projection optical system is configured to support an ultra-wide angle, where the half angle of view is 70 degrees or more, it will be possible to realize an LCD projector that supports an ultra-wide angle. Of course, the angle that determines whether or not an ultra-wide angle is supported is not limited to a value of 70 degrees or more.

[0035] An LCD projector that supports ultra-wide angles can display a large screen even in a small projection space. In other words, enlarged projection is possible even when the distance between the LCD projector and the screen is short. This provides the following advantages: Since the liquid crystal projector can be placed close to the screen, it is possible to sufficiently reduce the possibility that light from the liquid crystal projector will directly enter the human eye, thereby providing a high level of safety. Since shadows of people and other objects do not appear on the screen, efficient presentations are possible. There is a high degree of freedom in choosing the installation location, and it can be easily installed in narrow spaces or on ceilings with many obstacles. By installing it on a wall, maintenance such as cable routing is easier than when it is installed on a ceiling. For example, it is possible to increase the flexibility of settings such as meeting spaces, classrooms, and conference rooms.

[0036] FIG. 1 is a schematic diagram for explaining another advantage of the super-wide-angle liquid crystal projector. As shown in FIG. 1, by placing an ultra-wide-angle liquid crystal projector 1 on a table, it is possible to project an enlarged image 2 onto the same table. This type of usage is also possible, allowing for efficient use of space.

[0037] Recently, with the spread of interactive whiteboards in schools and workplaces, there has been an increasing demand for LCD projectors with ultra-wide viewing angles. Similar LCD projectors are also used in fields such as digital signage (electronic advertising). For example, electronic whiteboards can use technologies such as LCD (Liquid Crystal Display) and PDP (Plasma Display Panel). Compared to these technologies, using an ultra-wide-angle LCD projector makes it possible to provide a large screen at a lower cost. Ultra-wide-angle LCD projectors are also called short-focus projectors or ultra-short-focus projectors.

[0038] [Image projection onto a holographic screen] FIG. 2 is a schematic diagram showing an example of projecting an image onto a holographic screen. As shown in FIG. 2, in an image display system 4 using a projector 3, a holographic screen 5 can also be used as a transparent screen. As the projector 3 shown in FIG. 2, the liquid crystal projector 1 with an ultra-wide angle as exemplified in FIG. 1 may be used, or a projector that does not support an ultra-wide angle may be used.

[0039] 2, a holographic screen 5 formed of a transmission hologram is used as a transparent screen. A user can view an image 6 projected onto the holographic screen 5 so that the image 6 overlaps with the background.

[0040] As shown in FIG. 2, the projector 3 emits image light IL toward the rear surface 5a of the hologram screen 5. The image light IL incident on the rear surface 5a of the holographic screen 5 is diffused (scattered) by the holographic screen 5 and emitted outward from the front surface 5b. In this embodiment, the hologram screen 5 is designed so that light emitted in a direction perpendicular to the hologram screen 5 has the maximum gain relative to image light IL emitted obliquely from below. This makes it possible to provide a high-quality image with high visibility to a user viewing image 6 from a position approximately horizontal to hologram screen 5. Of course, the present invention is not limited to such a design. In this way, the holographic screen 5 has the function of displaying an image by controlling the traveling direction of the incident image light IL.

[0041] The material of the transmission hologram that constitutes the holographic screen is not limited, and any photosensitive material may be used. Alternatively, any holographic optical element (HOE) that functions as a transmission hologram may be used. The method of producing the holographic screen by exposure is also not limited, and the wavelengths and emission directions of the object light and reference light may be set as desired.

[0042] As the transparent screen, a screen that diffuses light using, for example, scattering materials such as fine particles, a Fresnel lens, a microlens, or the like may be used. The transparent screen may also be configured by a transparent display such as a transparent OLED using organic electroluminescence (OLE). Alternatively, any film, membrane, or the like that can diffuse the image light IL may be used as the transparent screen. Any other technology for realizing a transparent display surface may be used.

[0043] First Embodiment [Image display device] FIG. 3 is a schematic diagram showing an example of the configuration of a projection-type image display device according to a first embodiment of the present technology. The image display device 8 includes a light source 9 , an illumination optical system 10 , and a projection optical system 11 . The light source 9 is arranged to emit a light beam to the illumination optical system 10 . For example, a high-pressure mercury lamp or the like is used as the light source 9. Alternatively, a solid-state light source such as an LED (Light Emitting Diode) or an LD (Laser Diode) may be used.

[0044] The illumination optical system 10 is configured to uniformly irradiate the light beam emitted from the light source 9 onto the surface of the image modulation element (liquid crystal panel P) which serves as the primary image plane. In the illumination optical system 10, a light beam from a light source 9 passes through two fly-eye lenses FL, a polarization conversion element PS, and a condenser lens L in this order, and is converted into a uniform light beam with uniform polarization. The light beam that passes through the condenser lens L is separated into each of the RGB color component lights by a dichroic mirror DM, which reflects only light of a specific wavelength band. Each color component light of RGB is incident on a liquid crystal panel P (image modulation element) provided corresponding to each color of RGB via a total reflection mirror M, a lens L, etc. Then, each liquid crystal panel P performs optical modulation according to a video signal. The modulated color component lights are combined by a dichroic prism PP to generate image light that constitutes an image. The generated image light is then emitted toward the projection optical system 11.

[0045] The optical components that make up the illumination optical system 10 are not limited, and optical components different from the optical components described above may be used. For example, instead of the transmissive liquid crystal panel P, a reflective liquid crystal panel or a digital micromirror device (DMD) or the like may be used as the image modulation element. Furthermore, for example, instead of the dichroic prism PP, a polarizing beam splitter (PBS), a color synthesis prism that synthesizes the image signals of each color of RGB, or a TIR (Total Internal Reflection) prism may be used.

[0046] In this embodiment, the illumination optical system 10 functions as an image generating section that modulates light emitted from a light source and generates image light including a plurality of pixel lights. The pixel lights included in the image light are lights constituting each of the pixels included in the image projected onto the projection target. In this embodiment, the pixel lights are lights emitted from each of the pixels included in the image modulation element (liquid crystal panel P) that generates and emits the image light.

[0047] The projection optical system 11 adjusts the image light emitted from the illumination optical system 10 and enlarges and projects it onto a screen that serves as a secondary image surface. That is, the projection optical system 11 adjusts the image information on the primary image surface (liquid crystal panel P) and enlarges and projects it onto the secondary image surface (screen).

[0048] The image display device 8 according to this embodiment is configured as an image display device compatible with a super wide angle, as exemplified in FIG. The image display device 8 projects image light onto a hologram screen as shown in FIG. 2 as a projection target. Of course, the application of this technology is not limited to image display devices that support ultra-wide angles, nor is it limited to cases where a holographic screen is used as a projection target.

[0049] [Projection optical system] 4 to 8 are optical path diagrams showing specific configuration examples of the image display system 7 and the projection optical system 11 according to this embodiment. As shown in FIGS. 7 and 8, in this embodiment, image light IL is emitted from the illumination optical system 10 along a reference axis (hereinafter, this reference axis will be referred to as an optical axis O) that extends in a predetermined direction. That is, the dichroic prism PP shown in Figures 7 and 8 combines the RGB image light IL emitted from three liquid crystal panels P corresponding to each of the RGB colors and emits it along the optical axis O. 7 and 8 is disposed so that the emission direction of the image light IL is parallel to the optical axis O, i.e., perpendicular to the optical axis O. The other two liquid crystal panels P are disposed with respect to the dichroic prism PP so that the image light IL emitted by them is combined with the image light IL emitted from the liquid crystal panels P shown in FIGS.

[0050] 4 to 8, a liquid crystal panel P is illustrated schematically, which is disposed perpendicular to the optical axis O. In FIG. The liquid crystal panel P has a rectangular shape and has a pair of opposing long sides 13 and a pair of opposing short sides 14. The liquid crystal panel P emits image light IL that forms a rectangular image having a pair of opposing long sides and a pair of opposing short sides. Pixel light CL emitted from a plurality of pixels C arranged on the opposing long sides 13 of the liquid crystal panel P is focused on a screen (hologram screen) S, whereby an image of the opposing long side portions of the image is displayed. Pixel light CL emitted from a plurality of pixels C arranged on opposing short sides 14 of the liquid crystal panel P is focused on the screen S, whereby an image of the opposing short side portions of the image is displayed. Furthermore, by designing the shape of the screen S onto which the image light IL is projected to be curved, the shape of the image may not be rectangular, or the aspect ratio of the image on the long side of the image (the image formed by pixel light CL emitted from the long side 13 of the liquid crystal panel P) and the image on the short side of the image (the image formed by pixel light CL emitted from the short side 14 of the liquid crystal panel P) may be changed. In this embodiment, image light IL (plurality of pixel lights CL) is projected onto a screen S having a planar shape.

[0051] Hereinafter, the direction of the long side 13 (long side direction) of the liquid crystal panel P is defined as the X direction, and the direction of the short side 14 (short side direction) of the liquid crystal panel P is defined as the Y direction. Also, the extension direction of the optical axis O (the emission direction of the image light IL emitted from the illumination optical system 10) is defined as the Z direction. In this case, the Y direction corresponds to the direction of the short side of the image of the image light IL emitted to the lens system L1 of the projection optical system 11, and is an embodiment of the first direction according to the present technology. The X direction corresponds to the direction of the long side of the image of the image light IL emitted to the lens system L1 of the projection optical system 11, and is an embodiment of the second direction according to the present technology.

[0052] For example, in a three-dimensional space (XYZ space), the long and short side directions of an image displayed on a screen S vary depending on the position, orientation, shape, etc. of the screen S. The first direction (Y direction in this embodiment) and the second direction (X direction in this embodiment) are not the long side direction and short side direction of the image displayed on the screen S, but are directions defined by the image light L emitted to the projection optical system 11. In this embodiment, the first direction and the long side direction of the image actually displayed on the screen S are configured to be the same direction (Y direction), and the second direction and the short side direction of the image actually displayed on the screen S are configured to be the same direction (X direction).

[0053] 4 to 8, an XYZ coordinate system is defined so that the optical axis O is located on the Z axis. For convenience, the description will be given with the Y direction being the up-down direction (the positive side of the Y axis is the upside, and the negative side of the Y axis is the downside). Of course, application of the present technology is not limited to the orientation or posture in which the image display device 8 is used. 4 to 8, in this embodiment, the liquid crystal panel P is disposed at a position offset downward (toward the negative Y-axis) from the optical axis O. Then, image light IL (plurality of pixel light CL) is emitted from the liquid crystal panel P along the optical axis O. Note that emitting the image light IL (plurality of pixel lights CL) along the optical axis O is one embodiment of emitting the image light based on the reference axis.

[0054] FIG. 4 is a perspective view of the projection optical system 11 that projects the image light IL onto the screen S, as viewed obliquely from above. Figure 4 shows the optical paths of pixel light CL emitted from a total of nine pixels C: the central pixel of the liquid crystal panel P, the pixels at the four corners, the central pixel of each long side 13, and the central pixel of each short side 14. The pixel light CL is emitted as divergent light (diffused light) from the pixels C of the liquid crystal panel P. The emitted pixel light C is imaged on the screen S by the projection optical system 11 and displayed as pixels of the projection image.

[0055] FIG. 5 is a side view of the projection optical system 11 that projects the image light IL onto the screen S, as viewed along the X direction. FIG. 6 is a side view of the projection optical system 11 that projects the image light IL onto the screen S, as viewed along the Y direction. 5 and 6, similar to FIG. 4, show the optical paths of pixel light CL emitted from a total of nine pixels C, including the central pixel of the liquid crystal panel P, the four corner pixels, the central pixel of each long side 13, and the central pixel of each short side 14.

[0056] FIG. 7 is a cross-sectional view of the lens system L1 when the projection optical system 11 is cut along the Y axis. FIG. 7 shows the optical paths of pixel light CL emitted from a total of three pixels C, namely, the central pixel of the liquid crystal panel P and the central pixels on each long side 13.

[0057] FIG. 8 is a cross-sectional view of the lens system L1 when the projection optical system 11 is cut along the X axis. FIG. 8 shows the optical paths of pixel light CL emitted from a total of three pixels C, namely, the pixel at the center of the liquid crystal panel P and the pixels at the centers of the short sides 14.

[0058] 7 and 8 show the cross-sectional shapes of the optical surfaces (lens surfaces, reflecting surfaces, etc.) of the optical components included in the projection optical system 11. However, to simplify the illustrations, hatching and the like that represent the cross sections of the optical components are omitted.

[0059] FIG. 9 is a table showing an example of parameters related to image projection. FIG. 10 is a schematic diagram for explaining the parameters shown in FIG. The numerical aperture NA of the projection optical system 11 on the primary image plane side is 0.127. The horizontal and vertical lengths (H×VSp) of the image modulation element (liquid crystal panel P) are 8.16 mm and 4.59 mm. The center position (Chp) of the image modulation element is at a position of -3.4 mm, with the upward side from the optical axis O being positive. Therefore, as shown in FIGS. 4 to 8, the position 3.4 mm below the optical axis O is the center position of the image modulation element.

[0060] FIG. 11 shows lens data for the image display device. FIG. 11 shows data on optical components (lens surfaces) 1 to 27 arranged from the primary image plane (P) side toward the secondary image plane (S) side, and the curved screen S. The data for each optical component (lens surface) includes the radius of curvature in the Y direction (mm), the radius of curvature in the X direction (mm), the core thickness d (mm), the refractive index nd at the d line (587.56 nm), and the Abbe number νd at the d line. The radius of curvature (mm) in the Y direction is typically a parameter corresponding to the shape of the lens surface when viewed along the X direction. The radius of curvature (mm) in the X direction is typically a parameter corresponding to the shape of the lens surface when viewed along the Y direction.

[0061] In the lens data of FIG. 11, the lens surfaces S14 and S15 are rotationally symmetric aspherical (ASP) surfaces, and comply with the following formula.

[0062]

number

[0063] In equation (1), the following parameters are used: z: Sag amount c: Curvature at the vertex of the surface (CUY) k: Conic coefficient (K) A, B, C, D, E, F, G, H, J: 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, 20th order deformation coefficients h: Light height (h 2 =x 2 +y 2 ) The sag amount Z when the ray height h is input into equation (1) is used as a parameter that represents the shape of the lens surface according to the ray height. Note that the "sag amount" is the distance in the optical axis direction between a plane that passes through the vertex of the surface and is perpendicular to the optical axis O.

[0064] In the lens data of FIG. 11, the lens surfaces S21 and S22 are cylindrical surfaces (CYL). The generatrix direction of the cylindrical surface is set to be parallel to the Y direction, so the radius of curvature (mm) in the Y direction is ∞.

[0065] In the lens data of FIG. 11, the lens surfaces S24 and S26 are XY polynomial aspheric surfaces (XYP) and comply with the following formula.

[0066]

number

[0067] In equation (2), the following parameters are used: z: Sag amount c: Curvature at the vertex of the surface (CUY) k: Conic coefficient (K) Cj: monomial x m y n Coefficient of

[0068] In the lens data of FIG. 11, the lens surface S25 is an anamorphic aspheric surface (AAS) and satisfies the following formula.

[0069]

number

[0070] In equation (3), the following parameters are used: z: Sag amount CUX, CUY: x and y curvatures KX, KY: Conic coefficients of x and y AR, BR, CR, DR: Rotationally symmetric parts of the 4th, 6th, 8th, and 10th order deformations of the conic AP, BP, CP, DP: Rotationally asymmetric parts of the 4th, 6th, 8th, and 10th order deformations of the conic

[0071] FIG. 12 is a table showing aspheric coefficients for lens surfaces S14 and S15 (ASP), lens surfaces S24 and S26 (XYP), and lens surface S25 (ASS). The shape of each lens surface can be defined by the above (Equations 1) to (Equations 3) using the coefficients shown in Fig. 12. Note that in this embodiment, the shape of each lens surface is defined without using higher-order coefficients not shown in Fig. 12.

[0072] FIG. 12 also shows the parallel decentering in the X, Y, and Z directions (XDE, YDE, ZDE) and the rotational decentering around the axis (ADE, BDE, CDE) for the lens surfaces S24, S25, and S26. The lens surfaces S24 and S25 are arranged so as to be decentered parallel to the Y direction and Z direction, respectively, and rotated around the X axis. The lens surface S26 is disposed so as to be decentered parallel to the Z direction and rotated around the X axis. In this manner, in this embodiment, the lens surfaces S24 to S26 are arranged decentered, that is, configured as decentered aspherical reflecting surfaces.

[0073] 12 also shows the parallel decentering and rotational decentering of the lens surface S27 and the screen S. In this disclosure, the configurations of the image display device, image display system, and projection optical system according to the present technology are calculated as new, unconventional configurations of the respective embodiments by simulation using design software. In the lens data of FIG. 12, the lens surface S27 is data for clarifying the position of the screen S, and is data necessary for the simulation. The screen S is disposed so as to be eccentric in parallel along each of the Y and Z directions and rotated by 90° around the X-axis, so that the screen S is disposed so as to be perpendicular to the Z direction.

[0074] As shown in FIGS. 5 and 6, the projection optical system 11 according to this embodiment includes a lens system L1 and a reflection optical system L2. The lens system L1 is configured with an optical axis O (reference axis) as a reference at the position where the image light IL generated by the illumination optical system 10 is incident, and refracts and emits each of the multiple pixel lights CL contained in the generated image light IL. The reflective optical system L2 is configured with an optical axis O (reference axis) as a reference, and reflects the pixel light CL emitted from the lens system L1 onto the screen S while aligning the traveling directions of the light.

[0075] As shown in FIGS. 7 and 8, in this embodiment, the lens system L1 has eight optical components (rotationally symmetric lenses) RS1 to RS8 each having an axis of rotational symmetry, and two cylindrical lenses CYL1 and CYL2. The rotationally symmetric lenses RS1 to RS8 are arranged so that their respective rotationally symmetric axes coincide with the optical axis O. The rotationally symmetric axes of the rotationally symmetric lenses RS1 to RS8 can also be said to be the optical axes of the rotationally symmetric lenses RS1 to RS8. The rotationally symmetric lenses RS1 to RS8 are arranged on the optical axis O in this order from the illumination optical system 10 side (hereinafter referred to as the front side) to the screen S side (hereinafter referred to as the rear side). Cylindrical lenses CYL1 and CYL2 are arranged in this order on the optical axis O behind the rotationally symmetric lens RS8, which is located at the rearmost side. Cylindrical lenses CYL1 and CYL2 are arranged so that the generatrix of their cylindrical surfaces intersects with the optical axis O. In other words, they are arranged so that the vertices of their cylindrical surfaces intersect with the optical axis O.

[0076] The lens surface on the front side of the first rotationally symmetric lens RS1, which is closest to the illumination optical system 10, corresponds to the lens surface S3 in the lens data of FIG. The rear-stage lens surface of the rotationally symmetric lens RS8 located at the rearmost side corresponds to the lens surface S19 in the lens data of FIG. The rear-stage lens surface of the front-stage cylindrical lens CYL1 corresponds to the lens surface S21(CLY) in the lens data of Fig. 10. It corresponds to the front-stage lens surface S22(CLY) of the rear-stage cylindrical lens CYL2. Lens surfaces S3 to S23 shown in FIG. 10 function as a lens system L1, which refracts a plurality of pixel lights CL emitted from each pixel C of the liquid crystal panel P and emits the light to a reflective optical system L2.

[0077] Lens system L1 can be said to be an optical system with partial rotational symmetry. By arranging the rotational symmetry axes of rotationally symmetric lenses RS1 to RS8 so that they coincide with optical axis O, it is possible to reduce the size in the Y direction, thereby enabling the miniaturization of the device. The two cylindrical lenses CYL1 and CYL2 arranged at the rearmost stage of the lens system L1 can also be said to be a cylindrical lens group. With respect to each optical component included in the lens system L1, there may be cases where only a portion thereof, including an effective area where the image light IL is incident, is used. By using only a portion of the optical components, it is possible to reduce the size of the projection optical system 11.

[0078] As shown in FIGS. 4 to 6, the reflective optical system L2 is made up of three aspherical reflecting surfaces Mr1 to Mr3. Of the three aspherical reflecting surfaces Mr1 to Mr3, the aspherical reflecting surface Mr1 that reflects the plurality of pixel lights CL emitted from the lens system L1 is designated by the same reference numeral and is referred to as the first reflecting surface Mr1. The aspherical reflecting surface Mr2 that reflects the plurality of pixel lights CL reflected by the first reflecting surface Mr1 will be referred to as the second reflecting surface Mr2 using the same reference numeral. The aspherical reflecting surface Mr3 that reflects the plurality of pixel lights CL reflected by the second reflecting surface Mr2 onto the screen S (projection target) is referred to as the third reflecting surface Mr3 using the same reference numeral.

[0079] The first reflecting surface Mr1 corresponds to the lens surface S24 (XYP) in the lens data of FIG. The second reflecting surface Mr2 corresponds to the lens surface S25 (ASS) in the lens data of FIG. The third reflecting surface Mr3 corresponds to the lens surface S26(XYP) in the lens data of FIG.

[0080] The first to third reflecting surfaces Mr1 to Mr3 correspond to an embodiment of one or more curved reflecting surfaces having rotational asymmetry according to the present technology. These reflecting surfaces are aspherical surfaces having rotational asymmetry, and can also be called free-form surfaces. The first to third reflecting surfaces Mr1 to Mr3 are decentered free-form surfaces configured in a foldable shape. In this embodiment, the third reflecting surface Mr3 is a curved reflecting surface among one or more curved reflecting surfaces that constitute the reflective optical system L2, which reflects multiple pixel lights CL onto the screen S (projected object), and is one embodiment of the final reflecting surface related to the present technology.

[0081] As shown in FIGS. 4 to 6, the pixel light CL emitted from the lens system L1 is reflected by the first reflecting surface Mr1 to bend back upward (toward the positive side of the Y axis). The plurality of pixel lights CL reflected by the first reflecting surface Mr1 are reflected by the second reflecting surface Mr2, turning back toward the downward side (negative side of the Y axis). The plurality of pixel lights CL reflected by the second reflecting surface Mr2 are reflected obliquely upward by the third reflecting surface Mr3. The pixel lights CL reflected by the third reflecting surface Mr3 are projected onto a screen S disposed perpendicular to the Z direction. As shown in FIGS. 4 to 6, in this embodiment, an image display with an ultra-short focus is realized.

[0082] [Direction of light CL from multiple pixels reflected toward the screen S] The reflective optical system L2, which is made up of the first to third reflecting surfaces Mr1 to Mr3, aligns the traveling directions of the plurality of pixel lights CL and reflects them onto the screen S. That is, the traveling directions of the plurality of pixel lights CL heading from the third reflecting surface Mr3 towards the screen S are aligned. The plurality of image light beams CL are emitted as divergent light beams (diffused light beams) from the pixels C of the liquid crystal panel P. The traveling direction of the image light beams CL is determined by the traveling direction of the chief ray of the image light beams CL.

[0083] 7 and 8, in this embodiment, a diaphragm (aperture diaphragm) 16 is provided in the lens system L1. The chief ray of each of the plurality of pixel lights CL passes through the center of the diaphragm 16. In this embodiment, the center of the diaphragm 16 is located on the optical axis O. If the lens system L1 does not include an aperture 16, the present technology can be applied by defining, for example, the component light emitted along the optical axis O of each pixel light CL (along the Z direction) as the principal ray.

[0084] With reference to FIGS. 13 and 14, the evaluation of the traveling directions of the plurality of pixel lights CL reflected toward the screen S will be described. In this embodiment, a plurality of pixel lights CL are projected onto a flat screen S. Therefore, as shown in Figures 13A and 13b, the traveling direction of the pixel lights CL (principal rays) reflected toward the screen S can be evaluated based on the intersection angle (incidence angle) of the image lights CL (principal rays) with the screen S. As shown in Figure 13C, it is also possible to evaluate the direction of travel of pixel light CL (principal ray) reflected toward screen S using the intersection angle between a vector extending in the direction of travel of each pixel light CL (principal ray) and a predetermined reference vector in XYZ space.

[0085] First, as shown in Figures 13A to 13C, the position T1 (x, y, z) on the screen S is calculated for each pixel light CL (principal ray) using XYZ coordinates. Then, the position T2 (x', y', z') on the third reflecting surface Mr3 of each pixel light CL (principal ray) is calculated. Then, let (x-x') = ΔX, (y-y') = ΔY, and (z-z') = ΔZ.

[0086] 13A and 13B, the traveling direction of each pixel light CL is evaluated based on the intersection angle between the line segment connecting the position T1 and the position T2 and the screen S. 13A is a schematic diagram showing the intersection angle θX between the pixel light CL and the screen S when the projection optical system 11 is viewed along the Y direction. In other words, θX is the intersection angle in the X direction between the pixel light CL and the screen S. θX can be calculated using the following formula. θX=arctan(ΔX / ΔZ)

[0087] In the plurality of pixel lights CL, the variation in θX can be regarded as equivalent to the variation in the traveling direction of the pixel lights CL reflected toward the screen S when the projection optical system 11 is viewed along the Y direction. In this embodiment, the projection optical system 11 can align the traveling directions of the plurality of pixel lights CL and project them onto the screen S. Therefore, it is possible to project the plurality of pixel lights CL onto the screen S with the variation in θX sufficiently suppressed. Of course, it is also possible to realize projection onto the screen S with Δθ being equal for all pixel lights CL. In other words, it is also possible to make the incident angles of the pixel lights CL equal when viewed from the Y direction.

[0088] 13B is a schematic diagram showing the intersection angle θY between the pixel light CL and the screen S when the projection optical system 11 is viewed along the X direction. In other words, θY is the intersection angle in the Y direction between the pixel light CL and the screen S. θY can be calculated using the following formula. θY=arctan(ΔY / ΔZ)

[0089] In the plurality of pixel lights CL, the variation in θY can be regarded as equivalent to the variation in the traveling direction of the pixel lights CL reflected toward the screen S when the projection optical system 11 is viewed along the X direction. In this embodiment, the projection optical system 11 can align the traveling directions of the multiple pixel lights CL and project them onto the screen S. Therefore, it is possible to project the multiple pixel lights CL onto the screen S with the variation in θY sufficiently suppressed. Of course, it is also possible to realize projection onto the screen S with ΔY being equal for all pixel lights CL. In other words, it is also possible to make the incident angles of the pixel lights CL equal when viewed from the X direction.

[0090] In FIG. 13C, a vector V (ΔX, ΔY, ΔZ) is assumed with position T2 as the start point and position T1 as the end point, and the traveling direction of each pixel light CL is evaluated based on the angle θR between it and a predetermined reference vector RV. If the reference vector RV is a unit vector (0, 0, 1) parallel to the Z direction, θR can be calculated by the following formula. θR=arccos(ΔZ / (ΔX 2 + ΔY 2 + ΔZ 2 ) 1 / 2 )

[0091] In the plurality of pixel lights CL, the variation in θR can be regarded as equivalent to the variation in the traveling direction of the pixel lights CL reflected toward the screen S in three-dimensional space (XYZ coordinate space). In this embodiment, the projection optical system 11 can align the traveling directions of the plurality of pixel lights CL and project them onto the screen S. Therefore, it is possible to project the plurality of pixel lights CL onto the screen S with the variation in θR sufficiently suppressed. Of course, it is also possible to realize projection onto the screen S with ΔR being equal for all pixel lights CL. In other words, it is also possible to make the incident angles of each pixel light CL equal in three-dimensional space (XYZ coordinate space).

[0092] θX and θY shown in FIGS. 13A and 13B can also be said to be parameters for evaluating the traveling direction of pixel light CL (principal ray) when viewed from a predetermined direction. θR shown in FIG. 13C can also be said to be a parameter for evaluating the traveling direction of pixel light CL (principal ray) in three-dimensional space (XYZ coordinate space).

[0093] 14 shows the evaluation results of the traveling direction of pixel light CL for 25 pixels C extracted at equal intervals from half the area on the positive side in the X direction of the liquid crystal panel P. Specifically, a total of 25 pixels C are extracted from half the area of ​​the liquid crystal panel P, with five pixels C arranged along the X direction and five pixels C arranged along the Y direction. The optical path of the image light CL emitted from the pixels C in the positive half of the liquid crystal panel P in the X direction and the optical path of the pixel light CL emitted from the pixels C in the negative half of the liquid crystal panel P in the X direction are symmetrical to each other in the XYZ space.

[0094] 13 are numbers for the pixels C. On the right side of the liquid crystal panel P in FIG. For example, in the drawing of half of the liquid crystal panel P, the pixel C at the bottom left corner is numbered 1, and the pixel C at the bottom right corner is numbered 5. In the drawing of half of the liquid crystal panel P, the pixel C at the top left corner is numbered 21, and the pixel C at the top right corner is numbered 25. The pixel C at the center of half of the liquid crystal panel P is numbered 13.

[0095] FIG. 14 also illustrates evaluation of the traveling direction of each pixel light CL for the second and third embodiments described later.

[0096] ΔθX shown in Fig. 14 is the difference between θX shown in Fig. 13A and a reference design value. In this embodiment, 0° is set as the design value. That is, when the projection optical system 11 is viewed along the Y direction, the projection optical system 11 is designed so that the direction perpendicular to the screen S becomes the reference direction for the traveling direction of the pixel light CL. The reference design values ​​can also be considered ideal design values. Therefore, in this embodiment, when the projection optical system 11 is viewed along the Y direction, it can also be said that the projection optical system 11 is designed so that the chief ray of each pixel light CL is ideally incident on the screen S perpendicularly. Since the design value is 0°, ΔθX shown in Fig. 14 is equal to θX calculated by the above formula. In other words, ΔθX = θX.

[0097] ΔθY is the difference from the reference design value for θY shown in FIG. 13B. In this embodiment, the design value is set to 70°. That is, the projection optical system 11 is designed so that when the projection optical system 11 is viewed along the X direction, the direction that intersects with the screen S at an angle of 70° becomes the reference direction for the traveling direction of the pixel light CL. In other words, when the projection optical system 11 is viewed along the X direction, the projection optical system 11 is designed so that the chief ray of each pixel light CL ideally enters the screen S at an incident angle of 70°. If the angle between the chief ray and the screen S is taken as the incident angle, the incident angle is 90°-70°=20°. Since the design value is 70°, ΔθY shown in Fig. 14 is the value obtained by subtracting 70 from θY calculated by the above formula. In other words, ΔθY = θY - 70.

[0098] ΔθR is the difference between θR shown in FIG. 13C and a reference design value. In this embodiment, the design value is set to 70°. That is, the projection optical system 11 is designed so that the direction intersecting the Z direction in which the reference vector RV extends at 70° becomes the reference direction for the traveling direction of the pixel light CL. In other words, the projection optical system 11 is designed so that the chief ray of each pixel light CL ideally enters the screen S at an angle of 70° with respect to the Z direction. Since the design value is 70°, ΔθR shown in Fig. 14 is the value obtained by subtracting 70 from θR calculated by the above formula. In other words, ΔθR = θR - 70.

[0099] 14 shows the maximum value (max), minimum value (min), and standard deviation σ for ΔθX, ΔθY, and ΔθR. The maximum value (max) is the maximum amount of deviation on the positive side from the set value. The minimum value (min) is the maximum amount of deviation on the negative side from the set value. The standard deviation σ of ΔθX corresponds to the standard deviation of the distribution of the traveling direction of the pixel light CL reflected by the reflection optical system L2 when the projection optical system 11 is viewed along the Y direction. In this embodiment, it is 0.0525. The standard deviation σ of ΔθY corresponds to the standard deviation of the distribution of the traveling direction of the pixel light CL reflected by the reflection optical system L2 when the projection optical system 11 is viewed along the X direction. In this embodiment, it is 0.0266. The standard deviation σ of ΔθR corresponds to the standard deviation of the distribution of the traveling direction of the pixel light CL reflected by the reflection optical system L2, which is 0.0266 in this embodiment. As shown in the evaluation results of FIG. 14, the projection optical system 11 according to this embodiment can project a plurality of image light beams CL onto the screen S with the traveling directions of the chief rays aligned.

[0100] [Characteristic points of projection optical system 11] The following describes the distinctive features of the projection optical system 11 according to this embodiment. The points described below are not necessarily essential requirements for applying this technology. However, having the features described below is advantageous for aligning the traveling direction of the pixel light CL.

[0101] In order to explain the characteristic points of the projection optical system 11, as shown in FIGS. 15 and 16, the following parameters are set regarding the optical path of the image light IL (pixel light CL). The optical path of the chief ray of the pixel light CL is shown in Figures 15 and 16. The parameters shown in Figures 15 and 16 are set with respect to the optical path of the chief ray of the pixel light CL.

[0102] FIG. 15 is a diagram of the projection optical system 11 as viewed along the Y direction. FIG. 15 shows the optical path of pixel light (principal ray) CL emitted from a pixel C at the center of each short side 14 of the liquid crystal panel P. The pixel light CL emitted from the pixel C at the center of each short side 14 of the liquid crystal panel P becomes pixel light corresponding to the pixel at the center of the short side of the projected image, and is hereinafter referred to as short side pixel light CLS. 15 shows the optical paths of the light CLS of the two pixels on the shorter side. When the projection optical system 11 is viewed along the Y direction, the optical paths of the light CLS of the two pixels on the shorter side are symmetrical with respect to the optical axis O.

[0103] As shown in FIG. 15, when the projection optical system 11 is viewed along the Y direction, the following parameters are set for the pixel light CLS on the short side. θ0x: angle between the pixel light CLS on the short side and the optical axis O θ1x: the angle between the light CLS from the pixel on the short side incident on the first reflecting surface Mr1 and the light CLS from the pixel on the short side reflected by the first reflecting surface Mr1 θ2x: the angle between the light CLS from the pixel on the short side incident on the second reflecting surface Mr2 and the light CLS from the pixel on the short side reflected by the second reflecting surface Mr2 θLx: the angle between the light CLS from the pixel on the short side incident on the third reflecting surface Mr3 and the light CLS from the pixel on the short side reflected by the third reflecting surface Mr3 15. FIG. 15 also shows a schematic crossing angle θX (design value 0°) between the pixel light CLS on the short side and the screen S when the projection optical system 11 is viewed along the Y direction.

[0104] FIG. 16 is a diagram of the projection optical system 11 when viewed along the X direction of the image. FIG. 16 shows the optical path of pixel light (principal ray) CL emitted from a pixel C at the center of each long side 13 of the liquid crystal panel P. The pixel light CL emitted from the pixel C at the center of each long side 13 of the liquid crystal panel P becomes pixel light corresponding to the pixel at the center of the long side of the projected image, and is hereinafter referred to as long side pixel light CLL. 16 will be distinguished from one another. In this embodiment, the long-side pixel light CLL emitted from the pixel C1 closer to the optical axis of the liquid crystal panel P is referred to as the first long-side pixel light CLL1. The long-side pixel light CLL emitted from the pixel C2 farther from the optical axis of the liquid crystal panel P is referred to as the second long-side pixel light CLL1.

[0105] The first long side pixel light CLL1 corresponds to the pixel light corresponding to the pixel at the center of one long side of the image, and the second long side pixel light CLL2 corresponds to the pixel light corresponding to the pixel at the center of the other long side of the image. In the example shown in Figure 16, the image on the upper long side of the image is formed by the first long side pixel light CLL1. The image on the upper long side of the image is formed by the second long side pixel light CLL2. Note that when defining the first long-side pixel light CLL1 and the second long-side pixel light CLL2, there is no limitation on which of the two long sides of the image to select and associate them with. Any one of the two long sides of the image can be selected to define the first long-side pixel light CLL1. Then, the second long-side pixel light CLL2 can be defined for the other long side.

[0106] As shown in FIG. 16, when the projection optical system 11 is viewed along the X direction, the following parameters are set for the pixel lights CLL1 and CLL2 on the first and second long sides. θ0y: the intersection angle between the traveling direction of the pixel light CLL1 on the first long side and the traveling direction of the pixel light CLL2 on the second long side θ1y: the intersection angle between the traveling direction of the light beam CLL1 from the pixel on the first long side reflected by the first reflecting surface Mr1 and the traveling direction of the light beam CLL2 from the pixel on the second long side reflected by the first reflecting surface Mr1 θ2y: the intersection angle between the traveling direction of the light beam CLL1 from the pixel on the first long side reflected by the second reflecting surface Mr2 and the traveling direction of the light beam CLL2 from the pixel on the second long side reflected by the second reflecting surface Mr2 θLy: the intersection angle between the traveling direction of the light beam CLL1 from the pixel on the first long side reflected by the third reflecting surface Mr3 and the traveling direction of the light beam CLL2 from the pixel on the second long side reflected by the third reflecting surface Mr3 θa1: the angle between the first long side pixel light CLL1 incident on the third reflecting surface Mr3 and the first long side pixel light CLL1 reflected by the third reflecting surface Mr3 θa2: the angle between the second long side pixel light CLL2 incident on the third reflecting surface Mr3 and the second long side pixel light CLL2 reflected by the third reflecting surface Mr3 Note that θLy is the intersection angle when the first long side pixel light CLL1 and the second long side pixel light CLL2 incident on the screen S intersect at a very distant position, and is omitted because it is difficult to illustrate (in this embodiment, θLy is 0.0°, and the two light rays do not intersect). FIG. 16 also shows a schematic diagram of the intersection angle θY (design value 70°) between the pixel light CLL on the long side and the screen S when the projection optical system 11 is viewed along the X direction.

[0107] Fig. 17 is a table showing the numerical values ​​of the parameters set in Fig. 15 and Fig. 16. Characteristic points regarding the projection optical system 11 will be explained with reference to these numerical values ​​as needed.

[0108] (Power of the first to third reflecting surfaces Mr1 to Mr3) The numerical values ​​of the parameters shown in FIG. 15 are as follows: θ0x 6.6° θ1x 30.6° θ2x 91.4° θLx 112.5° These numerical values ​​give the optical power (refractive power) of the first to third reflecting surfaces Mr1 to Mr3 when the projection optical system 11 is viewed along the Y direction. Specifically, when the projection optical system 11 is viewed along the Y direction, it can be seen that the first reflecting surface Mr1 has negative power, the second reflecting surface Mr2 has negative power, and the third reflecting surface Mr3 has positive power.

[0109] The numerical values ​​of the parameters shown in FIG. 16 are as follows: θ0y 9.8° θ1y 7.3° θ2y 8.2° θLy 0.0° These numerical values ​​give the optical power (refractive power) of the first to third reflecting surfaces Mr1 to Mr3 when the projection optical system 11 is viewed along the X direction. Specifically, when the projection optical system 11 is viewed along the X direction, it can be seen that the first reflecting surface Mr1 has positive power, the second reflecting surface Mr2 has negative power, and the third reflecting surface Mr3 has positive power.

[0110] In this embodiment, three curved reflective surfaces are used to align the traveling directions of the multiple pixel light beams CL. Furthermore, when the projection optical system 11 is viewed along the Y direction and when viewed along the X direction, the power of at least one curved reflective surface is set to negative, thereby widening the angle of view. These points can be said to be one of the features of the projection optical system 11 according to this embodiment. The image light IL generated by the liquid crystal panel P is magnified and projected onto the screen S. At this time, the plurality of pixel lights CL are reflected in three stages by the first to third reflecting surfaces Mr1 to Mr3, and the traveling direction of the chief ray is aligned. Furthermore, in both the X and Y directions, at least one of the three stages of reflection is reflected in a direction that diffuses the plurality of pixel lights CL due to negative power. This is advantageous for aligning the traveling directions of the plurality of pixel lights CL while maintaining the image quality. Of course, it may be designed arbitrarily as to which of the first to third reflecting surfaces Mr1 to Mr3 should have negative power.

[0111] Focusing on the difference in power when the projection optical system 11 is viewed along the Y direction and when it is viewed along the X direction, the third reflecting surface Mr3, which is the final reflecting surface, has the largest difference in power. Among the one or more curved reflecting surfaces that make up the reflective optical system L2, one of the curved reflecting surfaces that has the largest difference between the power when the projection optical system 11 is viewed along the Y direction (first direction) and the power when the projection optical system 11 is viewed along the X direction (second direction) is the final reflecting surface, which is one of its characteristics. This configuration is advantageous in maintaining the aspect ratio of the image projected onto the screen S, making it possible to achieve high-quality image display. Note that the difference in optical power of the lens surfaces can also be expressed as a difference in curvature of the lens surfaces.

[0112] (Conditional formula (1) regarding θLx) The projection optical system 11 according to this embodiment is configured to satisfy the following relationship. (1) 0.25<θLx / 360<0.47

[0113] When θLx / 360 exceeds the upper limit defined in conditional expression (1), the position of the third reflecting surface Mr3 in the Z direction becomes closer to the screen S than the first reflecting surface Mr1. ​​In other words, the third reflecting surface Mr3 shown in FIG. 16 becomes a position that is moved to the right of the first reflecting surface Mr1 in the drawing. As a result, there is an increased possibility that the pixel light CL reflected by the third reflecting surface Mr3 will interfere with the first reflecting surface Mr1. When θLx / 360 is below the lower limit defined in conditional formula (1), the position of the third reflecting surface Mr3 in the Z direction becomes farther from the screen S than the second reflecting surface Mr2. That is, the third reflecting surface Mr3 shown in FIG. 16 becomes a position that is moved further to the left in the drawing than the second reflecting surface Mr2. As a result, there is an increased possibility that the pixel light CL reflected by the third reflecting surface Mr3 will interfere with the second reflecting surface Mr2. By configuring the projection optical system 11 so as to satisfy the conditional expression (1), it is possible to sufficiently avoid the above-described interference of the pixel light CL. As shown in FIG. 17, in this embodiment, θLx / 360 is 0.313, which satisfies conditional expression (1).

[0114] It is also possible to multiply each side of conditional expression (1) by 360 to obtain the following conditional expression: 90<θLx<170

[0115] (Conditional formula (2) regarding θLy) The projection optical system 11 according to this embodiment is configured to satisfy the following relationship. (2)―0.1<θLy / 360<0.1

[0116] If θLy / 360 exceeds the upper limit defined in conditional expression (2), the angle of incidence of the light beam becomes large, so the curvature of the reflecting surface becomes large, increasing the possibility of deteriorating the optical performance. If θLy / 360 falls below the lower limit defined in conditional formula (2), the angle of incidence of the light ray is small, and therefore a distance between optical systems L1 and L2 is required to project the desired size, which increases the possibility that the optical system will become large. By configuring the projection optical system 11 so as to satisfy conditional expression (2), it becomes possible to sufficiently suppress deterioration of optical performance and also to sufficiently avoid an increase in the size of the optical system. As shown in FIG. 16, in this embodiment, θLy / 360 is 0.0001, which satisfies conditional expression (2).

[0117] It is also possible to multiply each side of conditional expression (2) by 360 to obtain the following conditional expression: -36<θLx<36

[0118] (Conditional formula (3) regarding θa1 and θa2) The projection optical system 11 according to this embodiment is configured to satisfy the following relationship. (3) 0.35 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.96 MIN[θa1, θa2] is the smaller value of θa1 and θa2. MAX[θa1, θa2] is the larger value of θa1 and θa2.

[0119] If MIN[θa1, θa2] / MAX[θa1, θa2] exceeds the upper limit defined in conditional formula (3), multiple pixel lights CL will be focused on the screen S, increasing the possibility that the image will not be displayed properly. If MIN[θa1, θa2] / MAX[θa1, θa2] exceeds the lower limit defined in conditional formula (3), multiple pixel lights CL will be diffused onto the screen S, increasing the possibility that the image will not be displayed properly. By configuring the projection optical system 11 so as to satisfy the conditional expression (3), it is possible to sufficiently prevent an image from being displayed properly due to the collection and diffusion of the light from a plurality of pixels CL. As shown in FIG. 16, in this embodiment, MIN[θa1, θa2] / MAX[θa1, θa2] is θa1 / θa2, which is 0.741 and satisfies the conditional expression (3).

[0120] Regarding conditional expression (3), MAX[θa1, θa2] can be said to be the ray with the largest angle of view from the lens system L1 when the projection optical system 11 is viewed along the X direction. Furthermore, MIN[θa1, θa2] can also be said to be the ray with the smallest angle of view from the lens system L1 when the projection optical system 11 is viewed along the X direction.

[0121] The lower and upper limits of the conditional expressions (1) to (3) can be changed as appropriate depending on the configuration of the illumination optical system 10, the projection optical system 11, etc. For example, any values ​​within the above ranges can be selected as the lower and upper limits, and the optimum ranges can be set again.

[0122] For example, conditional expression (1) can be set to the following range: 0.30<θLx / 360<0.45 0.35<θLx / 360<0.42 0.40<θLx / 360<0.40

[0123] For example, conditional expression (2) can be set to the following range: -0.08<θLy / 360<0.08 -0.06<θLy / 360<0.06 -0.04<θLy / 360<0.04

[0124] For example, conditional expression (3) can be set to the following range: 0.5 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.96 0.6 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.96 0.7 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.96 0.75 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.91 0.78 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.88 0.81 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.85

[0125] For example, when focusing on the projection optical system 11 according to this embodiment, the projection optical system 26 according to a second embodiment and the projection optical system 29 according to a third embodiment, which will be described later, the following conditional expressions can be adopted: 0.7 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.96

[0126] [Projecting an image onto a holographic screen] In this embodiment, a holographic screen 5 shown in Fig. 2 is used as the screen S. Hereinafter, the screen S may be referred to as a holographic screen S. 4 to 6, a plurality of pixel lights CL with aligned chief rays are projected at an incident angle of 70 degrees onto a holographic screen S arranged along the vertical direction. The pixel lights CL incident on the holographic screen S are diffused (scattered) by the holographic screen S and emitted toward the user (viewer). In this embodiment, the holographic screen S is designed so that light emitted in a direction perpendicular to the screen surface (ie, Z direction) has the maximum gain relative to a plurality of pixel lights CL emitted from below. This makes it possible to provide a high-quality image with high visibility to a user viewing the image from a position substantially horizontal to the hologram screen S.

[0127] The diffraction efficiency of the transmission hologram that makes up the holographic screen S is a parameter that depends on the angle of incidence of light entering the transmission hologram. In other words, the diffraction efficiency of a transmission hologram depends on the angle of incidence. Incident angle dependence can also be called incident angle selectivity. If the traveling directions of the multiple pixel lights CL incident on the holographic screen S are not aligned, there will be variations in the incident angle of each pixel light CL incident on the holographic screen S. As a result, the diffraction efficiency for each pixel light CL will not be constant, and there is a high possibility that pixel lights that are diffused toward the viewer with high diffraction efficiency and pixel lights that are diffused toward the viewer with low diffraction efficiency will be mixed together. In other words, if the traveling directions of multiple pixel lights CL are not aligned, the intensity of the pixel lights CL diffracted by the holographic screen S will vary, which may result in an image with uneven brightness and color. There is also a possibility that significant distortion will occur. When these image irregularities and distortions are corrected by signal processing, the amount of correction becomes large, which may result in a significant drop in the brightness of the entire image, or may even make correction impossible.

[0128] Another possible method for correcting image unevenness and distortion is to change the irradiation angle of the reference light for each position when exposing the hologram screen S, thereby creating interference fringes (multi-slant) with different directions. In such a multi-slant hologram screen, alignment may be difficult because the misalignment of the angle between the image display device 8 and the hologram screen S has a significant effect on image quality. Also, a large optical system for changing the irradiation angle of the reference beam and a light source with high optical power density may be required, which may increase manufacturing costs.

[0129] In the image display device 8 according to this embodiment, a plurality of pixel lights CL are projected with the traveling direction of the chief rays aligned by the projection optical system 11. That is, it is possible to align the incident angles of the plurality of pixel lights CL onto the holographic screen S at any position on the screen surface.

[0130] Since the incident angle of the image light IL is kept substantially constant, it is possible to sufficiently suppress image unevenness and distortion due to the incident angle dependency of the hologram screen S, for example. As a result, it is possible to realize high-quality image display on the hologram screen S, for example. Furthermore, since there is no need to correct image signals, etc., it is possible to project images with the original illumination intensity of the image display device 8. This makes it possible to display bright images. Furthermore, it is possible to form interference fringes by keeping the reference light irradiation angle constant when exposing the hologram screen S. With such a mono-slant hologram screen S, high diffraction efficiency can be achieved by making multiple pixel lights CL incident at the same angle as the reference light irradiation angle. For example, a mono-slant transmission hologram screen is used in which the irradiation angle of the reference light is set to match the angle of incidence of the pixel light CL reflected by the reflection optical system L2 toward the hologram screen S. This makes it possible to realize a transparent display with extremely high brightness.

[0131] The mono-slant hologram screen can simplify the manufacturing process and reduce production costs, etc., compared to the multi-slant hologram screen. Furthermore, when a mono-slant beam is used, the interference fringes are oriented in a fixed direction, making it easy to align the screen with the image light IL. Therefore, by using the mono-slant hologram screen S, it is possible to provide an image display device 8 that is easy to maintain at low cost. Furthermore, since alignment is easy, it is possible to sufficiently reduce the influence of assembly variations and the like on the accuracy of the product. This makes it possible to provide a highly accurate product.

[0132] [Image aspect ratio] 15, in this embodiment, when the projection optical system 11 is viewed along the Y direction, the intersection angle θX between the pixel light CL and the screen S is designed to be 0°. In other words, when the projection optical system 11 is viewed along the Y direction, the traveling directions of the multiple pixel light rays CL are aligned so that they are incident perpendicularly on the screen S. 16, when the projection optical system 11 is viewed along the X direction, the intersection angle θY between the pixel light CL and the screen S is designed to be 70°. In other words, when the projection optical system 11 is viewed along the X direction, the traveling directions of the multiple pixel light CL are aligned so that the incident angle with respect to the screen S is 70°.

[0133] When image light IL is projected onto the screen S in the X and Y directions at θX and θY as shown in Figures 15 and 16, the following equation holds true for the angle of view (size) in the short side direction of the image projected onto the screen S. Angle of view in the short side direction of the projected image = Angle of view in the short side direction of the original image / cosθY In this embodiment, θY = 70°, so the angle of view of the short side of the projected image is enlarged by approximately 1.58 times. Therefore, in order to maintain the aspect ratio of the projected image, the angle of view (size) of the long side of the projected image must also be enlarged by the same amount.

[0134] 8, in this embodiment, two cylindrical lenses CYL1 and CYL2 are arranged so that the generatrix of the cylindrical surfaces (lens surfaces S21 and S22) is parallel to the Y axis. The two cylindrical surfaces (lens surfaces S21 and S22) enlarge the angle of view in the long side direction of the image light IL. In this way, by arranging the cylindrical lenses CYL1 and CYL2 within the lens system L1, it is possible to display a high-quality image with a simple configuration, while maintaining the aspect ratio of the original image. In this embodiment, maintaining the aspect ratio is easily achieved by using three curved reflecting surfaces (first to third reflecting surfaces Mr1 to Mr3) and by using cylindrical lenses CYL1 and CYL2. Of course, by appropriately adjusting the power (curvature) of each of the three curved reflecting surfaces (first to third reflecting surfaces Mr1 to Mr3), it is possible to maintain the aspect ratio of the image without using the cylindrical lenses CYL1 and CYL2. On the other hand, by using the cylindrical lenses CYL1 and CYL2, it is easy to maintain the aspect ratio.

[0135] In this embodiment, the cylindrical lenses CYL1 and CYL2 are an embodiment of an adjustment optical component that controls either the angle of view in the long side direction of the image or the angle of view in the short side direction of the image. As an embodiment of the adjustment optical component according to the present technology, an optical component other than a cylindrical lens may be used. In this embodiment, the angle of view in the long side direction of the image is enlarged by the adjustment optical component. However, this is not limiting, and the angle of view in the long side direction of the image may be reduced by the adjustment optical component. Furthermore, the angle of view in the short side direction of the image may be enlarged / reduced by the adjustment optical component. For example, the angle of view may be appropriately controlled in accordance with the incident angles in the X and Y directions in order to maintain the aspect ratio. Note that distortion correction may also be achieved by arranging the cylindrical lenses CYL1 and CYL2. In other words, arranging the adjustment optical component according to the present technology may also be advantageous for distortion correction.

[0136] [Image distortion] Figure 18 is a schematic diagram showing an example of distortion aberration of an image projected onto the holographic screen S. As shown in Figure 18, a nearly rectangular flat image is projected, demonstrating high performance. In addition, the aspect ratio of the image is maintained, achieving high-quality image display.

[0137] FIG. 19 is a graph showing an example of a lateral aberration diagram for a projected image. FIG. 19 shows the aberrations in the cross section in the horizontal direction (X direction) and the cross section in the vertical direction (Y direction) of five pixels C (numbered 1 to 5) of the liquid crystal panel P. At wavelengths of 641 nm, 522 nm, and 448 nm, indicated by the dotted line, solid line, and dashed line, the deviation on the image plane (vertical axis) is within a range of approximately 0.5 mm, indicating that high-precision images can be projected.

[0138] As described above, in the image display system 7 and image display device 8 according to this embodiment, the plurality of pixel lights CL that make up an image are refracted by the lens system L1 and emitted to the reflective optical system L2. The plurality of pixel lights CL are aligned in their traveling direction by the reflective optical system L2 and reflected onto the screen S. This makes it possible to realize high-quality image display. In this embodiment, the first to third reflecting surfaces Mr1 to Mr3 that make up the reflecting optical system L2 are configured as decentered free-form surfaces that can be folded, which makes it possible to align the traveling directions of multiple pixel lights CL and align the angles of incidence on the holographic screen S while maintaining high resolution, low distortion, and compactness.

[0139] <Second embodiment> An image display device according to a second embodiment of the present technology will be described. In the following description, the description of the same configurations and operations as those of the image display system 7 and image display device 8 described in the above embodiment will be omitted or simplified.

[0140] In an image display system 25 according to this embodiment, the screen S is disposed closer to the projection optical system 26 than in the first embodiment. In other respects, the configuration is substantially the same as in the first embodiment. The parameters relating to image projection have the values ​​shown in FIG. 9, similar to the first embodiment.

[0141] 20 to 24 are optical path diagrams showing specific configuration examples of the image display system 25 and the projection optical system 26 according to this embodiment. FIG. 25 shows lens data for the image display device. Fig. 26 is a table showing aspheric coefficients for lens surfaces S14 and S15 (ASP), lens surfaces S24 and S26 (XYP), and lens surface S25 (ASS). Fig. 26 also shows parallel decentering and rotational decentering for lens surface S27 and screen S. 27 and 28 are schematic diagrams showing parameters relating to characteristic points of the projection optical system 26. FIG. Fig. 29 is a table showing the numerical values ​​of the parameters set in Fig. 27 and Fig. 28. Fig. 29 also shows the numerical values ​​relating to conditional expressions (1) to (3). FIG. 30 is a schematic diagram showing an example of distortion aberration of an image projected onto the holographic screen S. In FIG. FIG. 31 is a graph showing an example of a lateral aberration diagram for a projected image.

[0142] 20 to 31 correspond to FIGS. 4 to 8, 11, 12, and 15 to 19 described in the first embodiment, and the description of the drawings will be omitted.

[0143] [Direction of light CL from multiple pixels reflected toward the screen S] 14, in this embodiment, the standard deviation σ of ΔθX is 0.0568, the standard deviation σ of ΔθY is 0.0222, and the standard deviation σ of ΔθR is 0.0222. As can be seen, in this embodiment as well, variations in ΔθX, ΔθY, and ΔθR are sufficiently suppressed. The projection optical system 26 according to this embodiment can project a plurality of image light beams CL onto the screen S with the traveling directions of the chief rays aligned.

[0144] [Characteristic points of the projection optical system 26] The projection optical system 26 according to this embodiment has the characteristic features explained above, as in the first embodiment, which will be briefly explained below.

[0145] (Power of the first to third reflecting surfaces Mr1 to Mr3) As shown in Figure 29, when the projection optical system 26 is viewed along the Y direction, the first reflecting surface Mr1 has negative power, the second reflecting surface Mr2 has negative power, and the third reflecting surface Mr3 has positive power. When the projection optical system 26 is viewed along the X direction, the first reflecting surface Mr1 has positive power, the second reflecting surface Mr2 has negative power, and the third reflecting surface Mr3 has positive power.

[0146] Three curved reflecting surfaces (first to third reflecting surfaces Mr1 to Mr3) are used as the reflecting optical system L2. In addition, the power of at least one curved reflecting surface is set to negative both when the projection optical system 26 is viewed along the Y direction and when it is viewed along the X direction, thereby widening the angle of view. This configuration is advantageous for aligning the traveling directions of multiple pixel lights CL while maintaining image quality. Furthermore, the third reflecting surface Mr3, which is the final reflecting surface, is configured to have the largest difference in power, which is advantageous for maintaining the aspect ratio of the image projected onto the screen S.

[0147] (Conditional formula (1) regarding θLx) As shown in FIG. 29, θLx / 360 is 0.422, which satisfies the conditional expression (1).

[0148] (Conditional formula (2) regarding θLy) As shown in FIG. 29, θLy / 360 is −0.0001, which satisfies conditional expression (2).

[0149] (Conditional formula (3) regarding θa1 and θa2) As shown in FIG. 29, MIN[θa1, θa2] / MAX[θa1, θa2] is θa1 / θa2, which is 0.891 and satisfies the conditional expression (3).

[0150] [Projecting an image onto a holographic screen] It is possible to achieve the same effects as in the first embodiment.

[0151] [Image aspect ratio] As shown in FIG. 24 and other figures, similarly to the first embodiment, cylindrical lenses CYL1 and CYL2 are arranged. In this embodiment as well, maintaining the aspect ratio is easily achieved by using three curved reflecting surfaces (first to third reflecting surfaces Mr1 to Mr3) and by using cylindrical lenses CYL1 and CYL2.

[0152] [Image distortion] As shown in Figure 30, a nearly rectangular flat image is projected, demonstrating high performance. The aspect ratio of the image is also maintained, achieving high-quality image display. As shown in Figure 31, at wavelengths of 641 nm, 522 nm, and 448 nm, indicated by dotted lines, solid lines, and dashed lines, the deviation on the image plane (vertical axis) is within a range of approximately 0.5 mm, indicating that high-precision images can be projected.

[0153] <Third embodiment> 32 to 36 are optical path diagrams showing specific configuration examples of an image display system 28 and a projection optical system 29 according to the third embodiment of the present technology. FIG. 37 shows lens data for the image display device. Fig. 38 is a table showing aspheric coefficients for lens surfaces S14 and S15 (ASP) and lens surface S20 (XYP). Fig. 38 also shows parallel decentering and rotational decentering for screen S. The lens surface S21 in FIG. 38 is data for clarifying the position of the screen S, and is data necessary for the simulation.

[0154] As shown in FIGS. 35 and 36, in this embodiment, the lens system L1 is made up of eight optical components (rotationally symmetric lenses) RS1 to RS8 each having an axis of rotational symmetry, and no cylindrical lens is disposed. The lens surface on the front side of the first rotationally symmetric lens RS1, which is closest to the illumination optical system 10, corresponds to the lens surface S3 in the lens data of FIG. The rear-stage lens surface of the rotationally symmetric lens RS8 located at the rearmost side corresponds to the lens surface S19 in the lens data of FIG. Lens surfaces S3 to S19 shown in FIG. 37 function as a lens system L1, which refracts a plurality of pixel lights CL emitted from each pixel C of the liquid crystal panel P and emits them to a reflective optical system L2. The lens system L1 can also be said to be an optical system having rotational symmetry.

[0155] 32 to 34, in this embodiment, the reflective optical system L2 is composed of one aspherical reflecting surface Mr. Hereinafter, one aspherical reflecting surface Mr will be simply referred to as reflecting surface Mr. The reflecting surface Mr corresponds to one embodiment of one curved reflecting surface. The reflecting surface Mr is a curved reflecting surface that reflects the pixel light CL emitted from the lens system L1 onto the screen S (projection target), and is one embodiment of the final reflecting surface according to the present technology. The reflecting surface Mr corresponds to the lens surface S20 (XYP) in FIG. As shown in FIG. 38, the reflecting surface Mr (lens surface S20) is disposed so as to be decentered parallel to the Z direction and rotated around the X axis.

[0156] 32 to 34 and 38, in this embodiment, the position of the screen S is also significantly different from that of the first and second embodiments. Specifically, the screen S is disposed above the image display device 8 in a substantially horizontal orientation (a direction substantially parallel to the XZ plane). As shown in FIGS. 32 to 34, the pixel light beams CL emitted from the lens system L1 are reflected by the reflecting surface Mr toward the upper side (the positive side of the Y axis) and toward the screen S.

[0157] [Direction of light CL from multiple pixels reflected toward the screen S] In this embodiment, a plurality of pixel lights CL are reflected onto the screen S by the reflective optical system L2, which is made up of one reflective surface Mr, with the traveling direction of the chief ray being aligned. The lens system L1 is provided with a diaphragm (aperture diaphragm) 16, and the light ray passing through the center of the diaphragm 16 becomes the chief ray of the pixel light CL. In this embodiment, the traveling directions of the multiple pixel lights CL reflected toward the screen S are evaluated using ΔθX, ΔθY, and ΔθR shown in FIGS. 13A and 13B. In this embodiment, the position of the screen S is significantly different from that of the first and second embodiments. On the other hand, ΔθX, ΔθY, and ΔθR can be calculated based on the position of the screen S.

[0158] 14, in this embodiment, the standard deviation σ of ΔθX is 0.1191, the standard deviation σ of ΔθY is 0.1205, and the standard deviation σ of ΔθR is 0.121. As can be seen, in this embodiment as well, variations in ΔθX, ΔθY, and ΔθR are sufficiently suppressed. The projection optical system 29 according to this embodiment can project a plurality of image light beams CL onto the screen S with the traveling directions of the chief rays aligned.

[0159] 14, in this embodiment, the variations in each of ΔθX, ΔθY, and ΔθR are relatively large compared to the first and second embodiments. In other words, it can be said that configuring the reflective optical system L2 using three concave reflective surfaces is more advantageous in aligning the traveling directions of the multiple pixel lights CL. On the other hand, when the reflective optical system L2 is configured using one concave reflecting surface, it is advantageous for reducing the number of parts, suppressing the cost of parts, and making the device smaller.

[0160] [Characteristic points of the projection optical system 29] The following describes the distinctive features of the projection optical system 29 according to this embodiment.

[0161] In order to explain the characteristic points of the projection optical system 29, as shown in FIGS. 39 and 40, the following parameters are set regarding the optical path of the image light IL (pixel light CL).

[0162] As shown in FIG. 39, when the projection optical system 29 is viewed along the Y direction, the following parameters are set for the pixel light CLS on the short side. θ0x: angle between the pixel light CLS on the short side and the optical axis O θLx: the angle between the light CLS of the pixel on the short side incident on the reflecting surface Mr and the light CLS of the pixel on the short side reflected by the reflecting surface Mr

[0163] As shown in FIG. 40, when the projection optical system 29 is viewed along the X direction, the following parameters are set for the pixel lights CLL1 and CLL2 on the first and second long sides. θ0y: the intersection angle between the traveling direction of the pixel light CLL1 on the first long side and the traveling direction of the pixel light CLL2 on the second long side θLy: the intersection angle between the traveling direction of the light beam CLL1 from the pixel on the first long side reflected by the reflecting surface Mr and the traveling direction of the light beam CLL2 from the pixel on the second long side reflected by the reflecting surface Mr θa1: the angle between the first long side pixel light CLL1 incident on the reflecting surface Mr and the first long side pixel light CLL1 reflected by the reflecting surface Mr θa2: the angle between the second long side pixel light CLL2 incident on the reflecting surface Mr and the second long side pixel light CLL2 reflected by the reflecting surface Mr

[0164] Note that the third reflecting surface Mr3 in the first and second embodiments and the reflecting surface Mr in this embodiment function as the final reflecting surface. In this regard, θ0x, θLx, θ0y, θLy, θa2, and θa1 shown in Figures 39 and 40 can be considered to be the same parameters as θ0x, θLx, θ0y, θLy, θa2, and θa1 used in describing the features of the first and second embodiments.

[0165] Fig. 41 is a table showing the numerical values ​​of the parameters set in Fig. 39 and Fig. 40. Characteristic points regarding the projection optical system 29 will be explained with reference to these numerical values ​​as needed.

[0166] (Power of the reflecting surface Mr) The parameter values ​​shown in Figure 39 are as follows: θ0x 13.1° θLx 13.2° From these numerical values, it can be seen that when the projection optical system 29 is viewed along the Y direction, the reflecting surface Mr has a positive power.

[0167] The numerical values ​​of the parameters shown in Figure 40 are as follows: θ0y 15.0° θLy 0.1° From these values, it can be seen that when the projection optical system 29 is viewed along the X direction, the reflecting surface Mr has a positive power.

[0168] Such a configuration can be said to be one of the features of the projection optical system 29 according to this embodiment. This configuration is advantageous in aligning the traveling directions of the plurality of pixel lights CL.

[0169] (Conditional formula (4) regarding θLx) The projection optical system 29 according to this embodiment is configured to satisfy the following relationship. (4) 0.02<θLx / 360<0.47

[0170] If θLx / 360 exceeds the upper limit defined in conditional expression (4), the angle of incidence of the pixel light CL incident on the reflecting surface Mr1 approaches 180 degrees, which makes it highly likely that reflection will become difficult. If θLx / 360 falls below the lower limit defined in conditional formula (4), the angle of incidence of the multiple pixel lights CL incident on the reflecting surface Mr1 is small, and therefore, space is required to project the light at the desired angle of view (projection size), which is likely to result in an increase in size. Configuring the projection optical system 29 so as to satisfy conditional expression (4) is advantageous for realizing high-quality image display. It is also possible to multiply each side of conditional expression (4) by 360 to obtain the following conditional expression: 7.2<θLx<170

[0171] The lower and upper limits of each of the conditional expressions (4) can be changed as appropriate depending on the configuration of the projection optical system 29, etc. For example, any values ​​within the above ranges can be selected as the lower and upper limits, and the optimum ranges can be set again.

[0172] For example, it is possible to set conditional expression (4) within the following range: 0.04<θLx / 360<0.45 0.06<θLx / 360<0.42 0.08<θLx / 360<0.40

[0173] (Conditional formula (2) regarding θLy) As shown in FIG. 41, θLy / 360 is 0.0415, which satisfies the conditional expression (2).

[0174] (Conditional formula (3) regarding θa1 and θa2) As shown in FIG. 41, MIN[θa1, θa2] / MAX[θa1, θa2] is θa1 / θa2, which is 0.924 and satisfies the conditional expression (3).

[0175] [Projecting an image onto a holographic screen] It is possible to achieve the same effects as those of the above embodiment.

[0176] [Image distortion] FIG. 42 is a schematic diagram showing an example of distortion aberration of an image projected onto the holographic screen S. In FIG. In this embodiment, no adjusting optical components such as a cylindrical lens are used. Therefore, compared to the first and second embodiments, maintaining the aspect ratio is somewhat more difficult. Specifically, as shown in FIG. 42, the long and short sides of the projected image are reversed, resulting in a vertically elongated image. However, it is possible to display a nearly rectangular planar image.

[0177] FIG. 43 is a graph showing an example of a lateral aberration diagram for a projected image. The deviation on the image plane (vertical axis) is slightly larger than in the first and second embodiments. Specifically, as shown in Fig. 43, the deviation on the image plane (vertical axis) is within a range of approximately 1.5 mm at wavelengths of 641 nm, 522 nm, and 448 nm, which are indicated by the dotted line, solid line, and dash-dot line, respectively. On the other hand, it is possible to project an image within this range of deviation, and a high-quality image display is realized.

[0178] <Fourth embodiment> 44 to 48 are optical path diagrams showing specific configuration examples of an image display system 32 and a projection optical system 33 according to the fourth embodiment of the present technology. 44 to 46 show the optical paths of pixel light CL emitted from a total of 25 pixels C arranged at equal intervals of five each along the X and Y directions in the entire area of ​​the liquid crystal panel P.

[0179] Fig. 47 is a cross-sectional view of the lens system L1 when cutting the projection optical system 33 along the Y axis. Fig. 47 shows the optical paths of pixel light CL emitted from a total of five pixels C: the central pixel of the liquid crystal panel P, the central pixels on each long side 13, and a pixel located between them. That is, Fig. 47 shows the optical paths of pixel light CL emitted from five pixels C arranged at equal intervals along the Y direction at the center of the liquid crystal panel P.

[0180] Figure 48 is a cross-sectional view of the lens system L1 when cutting the projection optical system 33 along the X axis. Figure 48 shows the optical paths of pixel light CL emitted from a total of five pixels C: the central pixel of the liquid crystal panel P, the central pixel of each short side 14, and a pixel located between them. That is, Figure 48 shows the optical paths of pixel light CL emitted from five pixels C arranged at equal intervals along the X direction at the center of the liquid crystal panel P.

[0181] FIG. 49 is a table showing an example of parameters related to image projection. In this embodiment, the center position (Chp) of the image modulation element is the same position as the optical axis O (offset amount 0.0). Therefore, as shown in FIGS. 44 to 48, the position of the optical axis O is the center position of the image modulation element.

[0182] 50 and 51 show lens data for the image display device. 52 and 53 are tables showing aspherical coefficients for lens surfaces S48 to S50 (XYP). In addition, Fig. 52 and Fig. 53 show parallel decentering and rotational decentering for lens surfaces S3 and S47 and screen S. The lens surface S51 in FIG. 51 is data for clarifying the position of the screen S, and is data necessary for the simulation.

[0183] As shown in FIGS. 47 and 48, in this embodiment, the lens system L1 is made up of 22 optical components (rotationally symmetric lenses) RS1 to RS22 each having an axis of rotational symmetry, and no cylindrical lens is disposed. The front-stage lens surface of the first rotationally symmetric lens RS1, which is closest to the illumination optical system 10, corresponds to lens surface S4 in the lens data of Fig. 50. The rear-stage lens surface of the rearmost rotationally symmetric lens RS22 corresponds to lens surface S46 in the lens data of Fig. 51.

[0184] In this embodiment, a lens surface S3 is defined as a decentered surface on the upstream side of the rotationally symmetric lens RS1, and a lens surface S47 is defined as a decentered surface on the downstream side of the rotationally symmetric lens RS22. Lens surfaces S3 to S47 shown in FIGS. 50 and 51 function as a lens system L1, which refracts a plurality of pixel lights CL emitted from each pixel C of the liquid crystal panel P and emits them to a reflective optical system L2.

[0185] As shown in FIGS. 44 to 46, the reflective optical system L2 is made up of a first reflecting surface Mr1, a second reflecting surface Mr2, and a third reflecting surface Mr3, similar to the first and second embodiments. The first reflecting surface Mr1 corresponds to the lens surface S48 (XYP) in the lens data of FIG. The second reflecting surface Mr2 corresponds to the lens surface S49 (XYP) in the lens data of FIG. The third reflecting surface Mr3 corresponds to the lens surface S50(XYP) in the lens data of FIG.

[0186] As shown in FIGS. 44 to 46, the pixel light CL emitted from the lens system L1 is reflected by the first reflecting surface Mr1 to bend back upward (towards the positive side of the Y axis). The plurality of pixel lights CL reflected by the first reflecting surface Mr1 are reflected downward (towards the negative side of the Y axis) by the second reflecting surface Mr2. The plurality of pixel lights CL reflected by the second reflecting surface Mr2 are reflected obliquely upward by the third reflecting surface Mr3 toward the lens system L1. Therefore, in this embodiment, the plurality of pixel lights CL reflected by the third reflecting surface Mr3 are projected onto the screen S in a direction from the positive side to the negative side of the Z axis. That is, in this embodiment, the direction (orientation) of projection of the image light IL onto the screen S is opposite to that in the first and second embodiments, and in this state, an image display with an ultra-short focus is realized.

[0187] [Direction of light CL from multiple pixels reflected toward the screen S] The reflective optical system L2, which is made up of the first to third reflecting surfaces Mr1 to Mr3, aligns the traveling directions of the plurality of pixel lights CL and reflects them onto the screen S. That is, the traveling directions of the plurality of pixel lights CL heading from the third reflecting surface Mr3 towards the screen S are aligned. The lens system L1 is provided with a diaphragm (aperture diaphragm) 16, and the light ray passing through the center of the diaphragm 16 becomes the chief ray of the pixel light CL.

[0188] FIG. 54 is a table showing the evaluation results of the traveling directions of a plurality of pixel lights CL reflected toward the screen S. 54, in this embodiment, the standard deviation σ of ΔθX is 0.1573, the standard deviation σ of ΔθY is 0.0296, and the standard deviation σ of ΔθR is 0.030. As can be seen, in this embodiment as well, variations in ΔθX, ΔθY, and ΔθR are sufficiently suppressed. The projection optical system 33 according to this embodiment can project a plurality of image light beams CL onto the screen S with the traveling directions of the chief rays aligned.

[0189] In this embodiment, the variation in ΔθX is relatively large. On the other hand, the variations in ΔθY and ΔθR are sufficiently suppressed. This can also be said to be one of the effects of configuring the reflective optical system L2 using three concave reflective surfaces. In other words, configuring the reflective optical system L2 using three concave reflective surfaces can be said to be an advantageous configuration in that it can also sufficiently suppress the variation in at least one of ΔθX, ΔθY, and ΔθR.

[0190] [Characteristic points of the projection optical system 33] The projection optical system 33 according to this embodiment has the characteristic features explained above, similar to those of the first and second embodiments, which will be briefly explained below.

[0191] 55 and 56 are schematic diagrams showing parameters relating to characteristic points of the projection optical system 33. FIG. Fig. 57 is a table showing the numerical values ​​of the parameters set in Fig. 55 and Fig. 56. Fig. 57 also shows the numerical values ​​relating to conditional expressions (1) to (3).

[0192] (Power of the first to third reflecting surfaces Mr1 to Mr3) As shown in Figure 57, when the projection optical system 33 is viewed along the Y direction, the first reflecting surface Mr1 has negative power, the second reflecting surface Mr2 has negative power, and the third reflecting surface Mr3 has positive power. When the projection optical system 33 is viewed along the X direction, the first reflecting surface Mr1 has positive power, the second reflecting surface Mr2 has negative power, and the third reflecting surface Mr3 has positive power.

[0193] Three curved reflecting surfaces (first to third reflecting surfaces Mr1 to Mr3) are used as the reflecting optical system L2. In addition, the power of at least one curved reflecting surface is set to negative both when the projection optical system 33 is viewed along the Y direction and when it is viewed along the X direction, thereby widening the angle of view. This configuration is advantageous for aligning the traveling directions of multiple pixel lights CL while maintaining image quality. Furthermore, the third reflecting surface Mr3, which is the final reflecting surface, is configured to have the largest difference in power, which is advantageous for maintaining the aspect ratio of the image projected onto the screen S.

[0194] (Conditional formula (1) regarding θLx) As shown in FIG. 29, θLx / 360 is 0.381, which satisfies the conditional expression (1).

[0195] (Conditional formula (2) regarding θLy) As shown in FIG. 29, θLy / 360 is −0.0000, which satisfies conditional expression (2).

[0196] (Conditional formula (3) regarding θa1 and θa2) As shown in FIG. 29, MIN[θa1, θa2] / MAX[θa1, θa2] is θa1 / θa2, which is 0.377 and satisfies the conditional expression (3).

[0197] [Projecting an image onto a holographic screen] It is possible to achieve the same effects as those of the above embodiment.

[0198] [Image distortion] FIG. 58 is a schematic diagram showing an example of distortion aberration of an image projected onto the holographic screen S. In FIG. In this embodiment, no adjusting optical components such as a cylindrical lens are used. Therefore, compared to the first and second embodiments, maintaining the aspect ratio is somewhat more difficult. Specifically, as shown in FIG. 58, the long and short sides of the projected image are reversed, resulting in a vertically elongated image. However, it is possible to display a nearly rectangular planar image.

[0199] FIG. 59 is a graph showing an example of a lateral aberration diagram for a projected image. At wavelengths of 641 nm, 522 nm, and 448 nm, indicated by the dotted line, solid line, and dashed line, the deviation on the image plane (vertical axis) is sufficiently suppressed to within approximately 1.5 mm, achieving high-quality image display.

[0200] [Conditions regarding the direction of travel of multiple pixel light CL] Further features of the projection optical system according to the present technology will be listed based on the evaluation results of the traveling directions of pixel light CL in the first to third embodiments shown in Fig. 14 and the evaluation results of the traveling directions of pixel light CL in the fourth embodiment shown in Fig. 54. Note that the following features are not essential requirements.

[0201] Focusing on ΔθR in each embodiment shown in Figures 14 and 54, it is possible to point out as a feature that the standard deviation of the distribution in the traveling direction of multiple pixel light CL reflected by the reflective optical system L2 is smaller than 0.13. Furthermore, focusing on ΔθR of the first, second and fourth embodiments shown in Figures 14 and 54, a feature of the reflective optical system L2 configured with the first to third reflective surfaces Mr1 to Mr3 is that the standard deviation of the distribution of the traveling directions of the multiple pixel light CL reflected by the third reflective surface Mr3 is smaller than 0.03. Furthermore, focusing on ΔθR in the third embodiment shown in FIG. 14, when the reflective optical system L2 is configured using one reflective surface Mr, it is possible to point out that the standard deviation of the distribution in the traveling direction of the multiple pixel light CL reflected by one reflective surface Mr is smaller than 0.13.

[0202] Focusing on ΔθX in each embodiment shown in Figures 14 and 54, when the projection optical system is viewed along the Y direction, it is possible to point out that the standard deviation of the distribution in the traveling direction of multiple pixel light CL reflected by the reflection optical system L2 is smaller than 0.16, which is a characteristic feature. Furthermore, focusing on ΔθX in the first, second and fourth embodiments shown in Figures 14 and 54, a feature of the reflection optical system L2 being configured using the first to third reflection surfaces Mr1 to Mr3 is that when the projection optical system is viewed along the Y direction, the standard deviation of the distribution of the propagation direction of the multiple pixel light CL reflected by the third reflection surface Mr3 is smaller than 0.16. Furthermore, focusing on ΔθX in the third embodiment shown in FIG. 14, a feature of the case where the reflective optical system L2 is configured using one reflective surface Mr is that, when the projection optical system is viewed along the Y direction, the standard deviation of the distribution of the propagation directions of multiple pixel light CL reflected by one reflective surface Mr is smaller than 0.12.

[0203] When focusing on ΔθX in the first to third embodiments shown in FIG. 14, it is possible to point out as a feature that when the projection optical system is viewed along the Y direction, the standard deviation of the distribution of the propagation direction of the multiple pixel light CL reflected by the reflection optical system L2 is smaller than 0.12. Furthermore, when focusing on ΔθX in the first and second embodiments shown in FIG. 14, a feature of the reflective optical system L2 being configured by the first to third reflective surfaces Mr1 to Mr3 is that when the projection optical system is viewed along the Y direction, the standard deviation of the distribution of the propagation directions of the multiple pixel light CL reflected by the third reflective surface Mr3 is smaller than 0.06.

[0204] Focusing on ΔθY in each embodiment shown in Figures 14 and 54, when the projection optical system is viewed along the X direction, it is possible to point out that the standard deviation of the distribution in the traveling direction of multiple pixel light CL reflected by the reflection optical system L2 is smaller than 0.13, which is a characteristic feature. Furthermore, focusing on ΔθY in the first, second and fourth embodiments shown in Figures 14 and 54, a feature of the reflection optical system L2 configured with the first to third reflection surfaces Mr1 to Mr3 is that, when the projection optical system is viewed along the X direction, the standard deviation of the distribution of the propagation directions of the multiple pixel light CL reflected by the third reflection surface Mr3 is smaller than 0.03. Furthermore, focusing on ΔθY in the third embodiment shown in FIG. 14, a feature of the reflective optical system L2 configured with one reflective surface Mr is that, when the projection optical system is viewed along the X direction, the standard deviation of the distribution of the propagation directions of the multiple pixel light CL reflected by one reflective surface Mr is smaller than 0.13.

[0205] Satisfying such a condition for the standard deviation σ is advantageous for realizing high-quality image display.

[0206] <Other embodiments> The present technology is not limited to the above-described embodiments, and various other embodiments can be realized.

[0207] In the above embodiment, examples of the configuration of the reflective optical system L2 have been described, including an example in which the reflective optical system L2 is configured with three concave reflecting surfaces and an example in which the reflective optical system L2 is configured with one concave reflecting surface. The configuration examples of the reflective optical system L2 are not limited to these examples. For example, the reflective optical system L2 may be configured using two concave reflective surfaces or four concave reflective surfaces. In other words, any number of concave reflective surfaces may be used to configure the reflective optical system L2. Furthermore, the reflective optical system L2 may be realized by arranging one or more concave reflecting surfaces without decentering them. Alternatively, the reflective optical system L2 may be configured using only a rotationally symmetric concave reflecting surface. Any other configuration may be employed to realize the reflective optical system L2.

[0208] In the above embodiment, the case where a holographic screen is used as the screen S has been described. The application of this technology is not limited to the case where the projection object is a hologram screen. For example, the present technology can be applied to cases where a Fresnel lens screen is used, and the above-mentioned effects can be achieved. This technology can be widely applied to other transparent screens, such as those having any other configuration. Typically, the image display system, image display device, and projection optical system according to the present technology are widely applicable to any projected object whose quality of the projected image depends on the direction of propagation (incident angle) of multiple pixel lights CL, and can exert advantageous effects. Furthermore, the present technology is not limited to being applied to a screen, but can also be applied to displaying an image on any projection object such as a table or the wall of a building, etc. The shape of the projection object is also not limited to being flat, but the present technology can also be applied to projection objects with curved surfaces.

[0209] The configurations of the image display system, image display device, projection optical system, lens system, reflective optical system, curved reflecting surface, screen, etc. described with reference to the drawings are merely one embodiment, and can be arbitrarily modified without departing from the spirit of the present technology. In other words, any other configurations, algorithms, etc. for implementing the present technology may be adopted.

[0210] In this disclosure, to facilitate understanding of the explanation, words such as "approximately," "almost," and "roughly" may be used as appropriate. However, there is no clear difference between using and not using words such as "approximately," "almost," and "roughly." That is, in the present disclosure, concepts that define shape, size, positional relationship, state, etc., such as "center," "central," "uniform," "equal," "same," "orthogonal," "parallel," "symmetrical," "extended," "axial direction," "cylindrical," "cylindrical," "ring-shaped," and "annular," are concepts that include "substantially center," "substantially central," "substantially uniform," "substantially equal," "substantially the same," "substantially orthogonal," "substantially parallel," "substantially symmetrical," "substantially extended," "substantially axial direction," "substantially cylindrical," "substantially cylindrical," "substantially ring-shaped," "substantially annular," and the like. For example, this also includes states that fall within a specified range (for example, a range of ±10%) based on criteria such as "perfectly centered," "perfectly central," "perfectly uniform," "perfectly equal," "perfectly the same," "perfectly perpendicular," "perfectly parallel," "perfectly symmetrical," "perfectly extended," "perfectly axial," "perfectly cylindrical," "perfectly cylindrical," "perfectly ring-shaped," and "perfectly annular." Therefore, even if the words "roughly," "almost," "approximately," etc. are not added, the concept expressed by adding "roughly," "almost," "approximately," etc. may be included. Conversely, a state expressed by adding "roughly," "almost," "approximately," etc. does not necessarily exclude a complete state.

[0211] In this disclosure, expressions using "more than," such as "greater than A" and "smaller than A," are expressions that comprehensively include both concepts that include equivalent to A and concepts that do not include equivalent to A. For example, "greater than A" is not limited to cases that do not include equivalent to A, but also includes "A or greater." Furthermore, "smaller than A" is not limited to "less than A," but also includes "A or less." When implementing the present technology, specific settings and the like may be appropriately adopted from the concepts included in "greater than A" and "smaller than A" so as to achieve the effects described above.

[0212] It is also possible to combine at least two of the features of the present technology described above. That is, the various features described in each embodiment may be arbitrarily combined without distinction between the embodiments. Furthermore, the various effects described above are merely examples and are not limiting, and other effects may also be achieved.

[0213] The present technology can also be configured as follows. (1) A light source and an image generating unit that modulates the light emitted from the light source to generate image light including a plurality of pixel lights; a lens system configured with a reference axis as a reference at a position where the generated image light is incident, the lens system refracting and emitting each of the plurality of pixel lights included in the generated image light; a reflection optical system configured with the reference axis as a reference and aligning the directions of travel of the plurality of pixel lights emitted from the lens system and reflecting them onto a projection target; a projection optical system having An image display device comprising: (2) The image display device according to (1), The standard deviation of the distribution of the traveling direction of the pixel light reflected by the reflection optical system is smaller than 0.16. Image display device. (3) The image display device according to (1) or (2), The reflective optical system includes one or more curved reflective surfaces having a rotationally asymmetric shape. Image display device. (4) The image display device according to (3), The one or more curved reflecting surfaces include a first reflecting surface that reflects the pixel light beams emitted from the lens system, a second reflecting surface that reflects the pixel light beams reflected by the first reflecting surface, and a third reflecting surface that reflects the pixel light beams reflected by the second reflecting surface onto the projection target. Image display device. (5) The image display device according to (4), The standard deviation of the distribution of the traveling directions of the pixel light reflected by the third reflecting surface is smaller than 0.16. Image display device. (6) The image display device according to (4) or (5), the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; When a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, When the projection optical system is viewed along the first direction, the first reflecting surface has a negative power, the second reflecting surface has a negative power, and the third reflecting surface has a positive power; When the projection optical system is viewed along the second direction, the first reflecting surface has a positive power, the second reflecting surface has a negative power, and the third reflecting surface has a positive power. Image display device. (7) The image display device according to (6), When the projection optical system is viewed along the first direction, the pixel light corresponding to the pixel at the center of the short side of the image is defined as short side pixel light, and the angle between the short side pixel light incident on the third reflecting surface and the short side pixel light reflected by the third reflecting surface is defined as θLx. 0.25<θLx / 360<0.47 are configured to satisfy the relationship Image display device. (8) The image display device according to (3), The one or more curved reflective surfaces is one curved reflective surface. Image display device. (9) The image display device according to (8), The standard deviation of the distribution of the traveling directions of the pixel light reflected by the one curved reflecting surface is smaller than 0.13. Image display device. (10) The image display device according to (8) or (9), the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; When a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, when the projection optical system is viewed along the first direction, the one curved reflective surface has a positive power; When the projection optical system is viewed along the second direction, the one curved reflecting surface has a positive power. Image display device. (11) The image display device according to (10), When the projection optical system is viewed along the first direction, the pixel light corresponding to the pixel at the center of the short side of the image is defined as short side pixel light, and the angle between the short side pixel light incident on the one curved reflective surface and the short side pixel light reflected by the one curved reflective surface is defined as θLx, 0.02<θLx / 360<0.47 are configured to satisfy the relationship Image display device. (12) The image display device according to any one of (3) to (11), the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; A direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, Among the one or more curved reflective surfaces, a curved reflective surface that reflects the plurality of pixel lights to the projection object is set as a final reflective surface, When the projection optical system is viewed along the second direction, The pixel light corresponding to the pixel at the center of one long side of the image is defined as a first long side pixel light, The pixel light corresponding to the pixel at the center of the other long side of the image is defined as a second long side pixel light, The angle between the first long side pixel light incident on the final reflection surface and the first long side pixel light reflected by the final reflection surface is defined as θa1, When the angle between the second long side pixel light incident on the final reflection surface and the second long side pixel light reflected by the final reflection surface is θa2, 0.35 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.96 are configured to satisfy the relationship Image display device. (13) The image display device according to any one of (3) to (12), the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; A direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, Among the one or more curved reflective surfaces, a curved reflective surface that reflects the plurality of pixel lights to the projection object is set as a final reflective surface, When the projection optical system is viewed along the second direction, The pixel light corresponding to the pixel at the center of one long side of the image is defined as a first long side pixel light, The pixel light corresponding to the pixel at the center of the other long side of the image is defined as a second long side pixel light, When the angle between the traveling direction of the light from the first long side pixel reflected by the final reflection surface and the traveling direction of the light from the second long side pixel reflected by the final reflection surface is θLy, -0.1<θLy / 360<0.1 are configured to satisfy the relationship Image display device. (14) The image display device according to any one of (3) to (13), the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; A direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, Among the one or more curved reflective surfaces, a curved reflective surface that reflects the plurality of pixel lights to the projection object is set as a final reflective surface, Among the one or more curved reflecting surfaces, the curved reflecting surface having the largest difference between the power when the projection optical system is viewed along the first direction and the power when the projection optical system is viewed along the second direction is the final reflecting surface. Image display device. (15) The image display device according to any one of (1) to (14), the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; The lens system includes an adjustment optical component that controls either the angle of view in the long side direction of the image or the angle of view in the short side direction of the image. Image display device. (16) The image display device according to (15), The adjustment optics includes a cylindrical lens. Image display device. (17) The image display device according to any one of (1) to (16), The traveling direction of the plurality of pixel lights is the traveling direction of the chief ray of each of the plurality of pixel lights. Image display device. (18) (a) a projection object onto which an image light including a plurality of pixel lights is projected to display an image; (b) A light source and an image generating unit that modulates light emitted from the light source to generate the image light including the plurality of pixel lights; a lens system configured with a reference axis as a reference at a position where the generated image light is incident, the lens system refracting and emitting each of the plurality of pixel lights included in the generated image light; a reflection optical system configured with the reference axis as a reference and aligning the directions of travel of the plurality of pixel lights emitted from the lens system and reflecting them onto a projection target; a projection optical system having an image display device having Equipped with The projection target displays the image by controlling the traveling direction of the plurality of pixel lights incident thereon. Image display system. (19) The image display system according to (18), The projection object is a hologram screen or a Fresnel lens screen. Image display system. (20) A projection optical system that projects image light including a plurality of pixel lights generated by modulating light emitted from a light source onto a projection target, a lens system configured with a reference axis as a reference at a position where the generated image light is incident, the lens system refracting and emitting each of the plurality of pixel lights included in the generated image light; a reflection optical system that is configured with the reference axis as a reference and that reflects the plurality of pixel lights emitted from the lens system onto the projection target while aligning the traveling directions of the light; A projection optical system comprising: (21) The image display device according to (2), The standard deviation of the distribution of the traveling direction of the pixel light reflected by the reflection optical system is smaller than 0.13. Image display device. (22) The image display device according to (5), The standard deviation of the distribution of the traveling direction of the pixel light reflected by the reflection optical system is smaller than 0.06. Image display device. (23) The image display device according to (2), the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; When a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, When the projection optical system is viewed along the first direction, the standard deviation of the distribution of the traveling direction of the pixel light reflected by the reflection optical system is smaller than 0.16. Image display device. (24) The image display device according to (23), When the projection optical system is viewed along the first direction, the standard deviation of the distribution of the traveling directions of the pixel light reflected by the reflection optical system is smaller than 0.12. Image display device. (25) The image display device according to (2) or (21) to (24), the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; When a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, When the projection optical system is viewed along the second direction, the standard deviation of the distribution of the traveling direction of the pixel light reflected by the reflection optical system is smaller than 0.13. Image display device. (26) The image display device according to (5), When the projection optical system is viewed along the first direction, the standard deviation of the distribution of the traveling directions of the pixel light reflected by the third reflecting surface is smaller than 0.16. Image display device. (27) The image display device according to (26), When the projection optical system is viewed along the first direction, the standard deviation of the distribution of the traveling directions of the pixel light reflected by the third reflecting surface is smaller than 0.06. Image display device. (28) The image display device according to (5), (26) or (27), When the projection optical system is viewed along the second direction, the standard deviation of the distribution of the traveling directions of the pixel light reflected by the third reflecting surface is smaller than 0.03. Image display device. (29) The image display device according to (9), When the projection optical system is viewed along the first direction, a standard deviation of a distribution of the traveling directions of the pixel light reflected by the one curved reflecting surface is smaller than 0.12. Image display device. (30) The image display device according to (9) or (29), When the projection optical system is viewed along the second direction, the standard deviation of the distribution of the traveling directions of the pixel light reflected by the one curved reflecting surface is smaller than 0.13. Image display device. (31) The image display device according to (12), 0.7 <MIN[θa1,θa2] / MAX[θa1,θa2]<0.96 are configured to satisfy the relationship Image display device. (32) The image display device according to (17), the lens system has an aperture; The chief ray of each of the plurality of pixel lights is a ray that passes through the center of the aperture. Image display device. [Explanation of symbols]

[0214] C...pixel CL...pixel light CLL: Long side pixel light CLL1: First long side pixel light CLL2: Second long side pixel light CLS: Short side pixel light CYL...Cylindrical lens IL...Image light L1: Lens system L2…Reflection optical system Mr... 1 reflective surface Mr1...first reflecting surface Mr2: Second reflective surface Mr3...Third reflective surface RS...Rotationally symmetric lens O…Optical axis P...LCD panel S...Screen 7, 25, 28, 32...Image display system 8...Image display device 9…Light source 10…Illumination optical system 11, 26, 29, 33...Projection optical system 13...Long side of LCD panel 14...Short side of LCD panel 16...Aperture

Claims

1. A light source and an image generating unit that modulates the light emitted from the light source to generate image light including a plurality of pixel lights; a lens system configured with a reference axis as a reference at a position where the generated image light is incident, the lens system refracting and emitting each of the plurality of pixel lights included in the generated image light; a reflection optical system configured with the reference axis as a reference and aligning the directions of travel of the plurality of pixel lights emitted from the lens system and reflecting them onto a projection target; a projection optical system having Equipped with the traveling directions of the plurality of pixel lights are traveling directions of chief rays of the plurality of pixel lights, the reflective optical system includes one or more curved reflective surfaces having a rotationally asymmetric shape; the one or more curved reflective surfaces include a first reflective surface that reflects the plurality of pixel light beams emitted from the lens system, a second reflective surface that reflects the plurality of pixel light beams reflected by the first reflective surface, and a third reflective surface that reflects the plurality of pixel light beams reflected by the second reflective surface onto the projection target, a standard deviation of a distribution of the traveling directions of the pixel light reflected by the third reflecting surface is smaller than 0.16; the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; When a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, When the projection optical system is viewed along the first direction, the first reflecting surface has a negative power, the second reflecting surface has a negative power, and the third reflecting surface has a positive power; When the projection optical system is viewed along the second direction, the first reflecting surface has a positive power, the second reflecting surface has a negative power, and the third reflecting surface has a positive power. Image display device.

2. 2. The image display device according to claim 1, When the projection optical system is viewed along the first direction, the pixel light corresponding to the pixel at the center of the short side of the image is defined as short side pixel light, and the angle between the short side pixel light incident on the third reflecting surface and the short side pixel light reflected by the third reflecting surface is defined as θLx. 0.25<θLx / 360<0.47 are configured to satisfy the relationship Image display device.

3. 2. The image display device according to claim 1, a curved reflective surface among the one or more curved reflective surfaces that reflects the plurality of pixel lights to the projection object as a final reflective surface, When the projection optical system is viewed along the second direction, The pixel light corresponding to the pixel at the center of one long side of the image is defined as a first long side pixel light, the pixel light corresponding to the pixel at the center of the other long side of the image is defined as a second long side pixel light, The angle between the first long side pixel light incident on the final reflection surface and the first long side pixel light reflected by the final reflection surface is defined as θa1, When the angle between the second long side pixel light incident on the final reflection surface and the second long side pixel light reflected by the final reflection surface is θa2, 0.35<MIN[θa1, θa2] / MAX[θa1, θa2]<0.96 are configured to satisfy the relationship Image display device.

4. 2. The image display device according to claim 1, a curved reflective surface among the one or more curved reflective surfaces that reflects the plurality of pixel lights to the projection object as a final reflective surface, When the projection optical system is viewed along the second direction, The pixel light corresponding to the pixel at the center of one long side of the image is defined as a first long side pixel light, the pixel light corresponding to the pixel at the center of the other long side of the image is defined as a second long side pixel light, When the angle between the traveling direction of the light from the first long side pixel reflected by the final reflection surface and the traveling direction of the light from the second long side pixel reflected by the final reflection surface is defined as θLy, -0.1<θLy / 360<0.1 are configured to satisfy the relationship Image display device.

5. 2. The image display device according to claim 1, a curved reflective surface among the one or more curved reflective surfaces that reflects the plurality of pixel lights to the projection object as a final reflective surface, Among the one or more curved reflecting surfaces, the curved reflecting surface having the largest difference between the power when the projection optical system is viewed along the first direction and the power when the projection optical system is viewed along the second direction is the final reflecting surface. Image display device.

6. 2. The image display device according to claim 1, The lens system includes an adjustment optical component that controls either the angle of view in the long side direction of the image or the angle of view in the short side direction of the image. Image display device.

7. 7. The image display device according to claim 6, The adjustment optics includes a cylindrical lens. Image display device.

8. (a) a projection object onto which an image light including a plurality of pixel lights is projected to display an image; (b) A light source and an image generating unit that modulates light emitted from the light source to generate the image light including the plurality of pixel lights; a lens system configured with a reference axis as a reference at a position where the generated image light is incident, the lens system refracting and emitting each of the plurality of pixel lights included in the generated image light; a reflection optical system that is configured with the reference axis as a reference and that reflects the plurality of pixel lights emitted from the lens system onto the projection target while aligning the traveling directions of the light; a projection optical system having and the traveling directions of the plurality of pixel lights are traveling directions of chief rays of the plurality of pixel lights, the reflective optical system includes one or more curved reflective surfaces having a rotationally asymmetric shape; the one or more curved reflective surfaces include a first reflective surface that reflects the plurality of pixel light beams emitted from the lens system, a second reflective surface that reflects the plurality of pixel light beams reflected by the first reflective surface, and a third reflective surface that reflects the plurality of pixel light beams reflected by the second reflective surface onto the projection target, a standard deviation of a distribution of the traveling directions of the pixel light reflected by the third reflecting surface is smaller than 0.16; the image generation unit emits the image light constituting a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, to the lens system with the reference axis as a reference; When a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, When the projection optical system is viewed along the first direction, the first reflecting surface has a negative power, the second reflecting surface has a negative power, and the third reflecting surface has a positive power; When the projection optical system is viewed along the second direction, the first reflecting surface has a positive power, the second reflecting surface has a negative power, and the third reflecting surface has a positive power. Image display device Equipped with The projection target displays the image by controlling the traveling direction of the plurality of pixel lights incident thereon. Image display system.

9. 9. The image display system according to claim 8, The projection object is a hologram screen or a Fresnel lens screen. Image display system.

10. A projection optical system that projects image light including a plurality of pixel lights generated by modulating light emitted from a light source onto a projection target, a lens system configured with a reference axis as a reference at a position where the generated image light is incident, the lens system refracting and emitting each of the plurality of pixel lights included in the generated image light; a reflection optical system that is configured with the reference axis as a reference and that reflects the plurality of pixel lights emitted from the lens system onto the projection target while aligning the traveling directions of the light; Equipped with the traveling directions of the plurality of pixel lights are traveling directions of chief rays of the plurality of pixel lights, the reflective optical system includes one or more curved reflective surfaces having a rotationally asymmetric shape; the one or more curved reflective surfaces include a first reflective surface that reflects the plurality of pixel light beams emitted from the lens system, a second reflective surface that reflects the plurality of pixel light beams reflected by the first reflective surface, and a third reflective surface that reflects the plurality of pixel light beams reflected by the second reflective surface onto the projection target, a standard deviation of a distribution of the traveling directions of the pixel light reflected by the third reflecting surface is smaller than 0.16; the image light forms a rectangular image having a pair of long sides opposed to each other and a pair of short sides opposed to each other, and is emitted to the lens system with the reference axis as a reference; When a direction corresponding to a short side direction of the image of the image light emitted to the lens system is defined as a first direction, and a direction corresponding to a long side direction of the image of the image light emitted to the lens system is defined as a second direction, When the projection optical system is viewed along the first direction, the first reflecting surface has a negative power, the second reflecting surface has a negative power, and the third reflecting surface has a positive power; When the projection optical system is viewed along the second direction, the first reflecting surface has a positive power, the second reflecting surface has a negative power, and the third reflecting surface has a positive power. Projection optical system.

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