Optical filter and image display device

Abstract

An optical filter according to the present technology comprises a first layer and a second layer. The first layer has a first refractive index, is provided with a prism array in which a plurality of prisms are arranged, and has: a light incidence surface which is the surface on the reverse side from the prism array; and a boundary surface which is the surface on the reverse side from the light incidence surface and which is the surface of the prism array. If the angle that the boundary surface forms with the light incidence surface is defined as an angle of inclination, in at least a portion of the boundary surface, the angle of inclination is greater than the critical angle of the boundary surface. The second layer is laminated on the boundary surface, has a second refractive index, and has a light emission surface which is the surface on the reverse side from the boundary surface. The second refractive index is less than the first refractive index and equal to or greater than a third refractive index, which is the refractive index of the atmosphere.

Description

Optical filter and image display device

[0001] The present technology relates to an optical filter for capturing an image displayed on an image display device, and an image display device.

[0002] Virtual production is a video production technique in which an actual subject and a background displayed on an image display device are simultaneously photographed and then composited in real time. However, when an image displayed on an image display device is photographed, moiré (interference fringes) may occur. For this reason, techniques have been developed to reduce moiré by blurring the image using beam separation, such as a diffraction grating or prism, in the image display device. For example, Patent Literature 1 discloses an image display device in which an optical low-pass filter, which is a diffraction grating or prism, is placed in front of the image display body.

[0003] Japanese Unexamined Patent Publication No. 8-122709

[0004] However, when light rays are separated by the diffraction effect of a diffraction grating as described in Patent Document 1, the ratio of the amount of diffracted light of each order varies depending on the wavelength in a diffraction grating with a single grating pitch and grating depth. Since the light source wavelength of an image display device has multiple wavelengths such as RGB, the ratio of zeroth order light and ±1st order light varies between wavelengths, which can disrupt the color balance depending on the observation angle and potentially impair the quality of the image.

[0005] Furthermore, when light rays are separated by refraction through a prism, the maximum refraction angle that can be obtained is up to the critical angle of the prism, and the separation angle of the light rays cannot be increased, so it is necessary to increase the distance between the image display device and the optical filter, which causes problems such as an increase in the weight of the image display device and a decrease in the ease of holding the optical filter and installing the image display device.

[0006] In view of the above circumstances, an object of the present technology is to provide an optical filter and an image display device that are capable of suppressing moire without impairing image quality and are suitable for thinning.

[0007] To achieve the above object, an optical filter according to one aspect of the present technology includes a first layer and a second layer. The first layer has a first refractive index and is provided with a prism array in which a plurality of prisms are arranged, and has a light incident surface opposite to the prism array and a boundary surface opposite to the light incident surface and being the surface of the prism array, where the angle formed by the boundary surface with the light incident surface is defined as an inclination angle , and at least a portion of the boundary surface has the inclination angle greater than a critical angle of the boundary surface. The second layer is stacked on the boundary surface and has a second refractive index and has a light exit surface opposite to the boundary surface, where the second refractive index is smaller than the first refractive index and is equal to or greater than a third refractive index that is the refractive index of the atmosphere.

[0008] The prism array may be configured to be non-diffractive.

[0009] The prism array may have a prism pitch greater than 25 μm.

[0010] The boundary surface may be configured as an inclined surface that is inclined with respect to the light incident surface, and the inclination angle is larger than the critical angle.

[0011] Each prism constituting the prism array may be composed of a plurality of the inclined surfaces, and the inclined surfaces may be flat surfaces.

[0012] The prism may have an n-sided pyramid shape, where n is a natural number of 3 or more.

[0013] Each prism constituting the prism array may be composed of a plurality of the inclined surfaces, and the inclined surfaces may be curved surfaces.

[0014] The boundary surface may be composed of an inclined surface that is inclined with respect to the light incident surface and has an inclination angle greater than the critical angle, and a parallel surface that is parallel to the light incident surface.

[0015] Each prism constituting the prism array may be composed of a plurality of the inclined surfaces and the parallel surfaces, and the inclined surfaces may be flat surfaces.

[0016] The prism may have an n-sided truncated pyramid shape, where n is a natural number of 3 or more.

[0017] Each prism constituting the prism array may be composed of a plurality of the inclined surfaces and the parallel surfaces, and the inclined surfaces may be curved surfaces.

[0018] In each of the prisms, the projected area of ​​each of the inclined surfaces onto a plane parallel to the light incident surface may be the same as the projected area of ​​each of the parallel surfaces onto a plane parallel to the light incident surface.

[0019] The boundary surface may have a first inclined surface inclined with respect to the light incident surface, the inclination angle of which is a first angle, and a second inclined surface inclined with respect to the light incident surface, the inclination angle of which is a second angle different from the first angle, and at least one of the first angle and the second angle may be greater than the critical angle.

[0020] The optical filter has an inclination angle of θ Ｓ , the first refractive index is n １ , the second refractive index is n ２ , the third refractive index is n ３ Then, the following (Equation 1) may be satisfied: θ Ｓ [°] ≥ 99.296 · ΔN + 62.034 (Equation 1) where ΔN = (n １ -n ２ ) (n ２ -n ３ )

[0021] Each prism constituting the prism array may be divided into a plurality of portions.

[0022] To achieve the above object, an image display device according to an embodiment of the present technology includes an image display body, a spacer, and an optical filter. The image display body has a pixel group in which a plurality of pixels are arranged. The spacer is laminated on the image display body. the optical filter is an optical filter stacked on the side of the spacer opposite to the image display body, the optical filter having a first refractive index and a prism array in which a plurality of prisms are arranged, the optical filter having a light incident surface which is the surface opposite to the prism array, and a boundary surface which is the surface opposite to the light incident surface and is the surface of the prism array, the angle between the boundary surface and the light incident surface being an inclination angle, the inclination angle of at least a part of the boundary surface being larger than a critical angle of the boundary surface; and a second layer stacked on the boundary surface, having a second refractive index, and having a light exit surface which is the surface opposite to the boundary surface, the second refractive index being smaller than the first refractive index and being equal to or greater than a third refractive index which is the refractive index of the atmosphere, the optical filter is arranged so that the light incident surface faces the spacer, and light emitted from each pixel of the pixel group is incident on the light incident surface via the spacer.

[0023] 1 is a schematic diagram of an image display device according to an embodiment of the present technology; FIG. 1 is an enlarged view of the image display device; FIG. 2 is a schematic diagram of light beam separation by an optical filter of the image display device; FIG. 3 is a schematic diagram showing an arrangement of real images and virtual images of pixels by the optical filter; FIG. 4 is a schematic diagram showing the effect of light beam separation; FIG. 5 is a schematic diagram showing the effect of light beam separation; FIG. 6 is a cross-sectional view of the optical filter; FIG. 7 is a perspective view of a prism array provided in the optical filter; FIG. 8 is a plan view of the prism array; FIG. 9 is a perspective view of prisms constituting the prism array; FIG. 10 is a schematic diagram of the prism array; FIG. 11 is a schematic diagram showing the effect of the optical filter on light rays; FIG. 12 is a schematic diagram showing the effect of the optical filter on light rays; FIG. 13 is a schematic diagram showing the effect of the optical filter on light rays; FIG. 14 is a schematic diagram showing the effect of an optical filter according to a comparative example on light rays; FIG. 15 is a schematic diagram showing the effect of an optical filter according to a comparative example on light rays; FIG. 16 is a schematic diagram showing the arrangement of real images and virtual images by the optical filter according to the comparative example; FIG. 17 is a schematic diagram showing reflection of light by a light exit surface of the optical filter. 1 is a schematic diagram showing reflection of light by a light exit surface of the optical filter. FIG. 2 is a graph showing the relationship between an inclination angle and an incident angle in the optical filter. FIG. 3 is a graph plotting the inclination angle against ΔN in the optical filter. FIG. 4 is a graph showing the relationship between a prism pitch and a peak angle of separated light. FIG. 5 is a simulation result of a real image and a virtual image in a state in which the optical filter is removed from the image display device according to Configuration Example 1 of the present technology. FIG. 6 is a simulation result of a real image and a virtual image in the image display device. FIG. 7 is a simulation result of a real image and a virtual image in an image display device according to a comparative example. FIG. 8 is a perspective view of a prism included in an optical filter according to Configuration Example 2 of the present embodiment. FIG. 9 is a schematic diagram of the optical filter. FIG. 10 is a perspective view of a prism array included in the optical filter. FIG. 11 is a plan view of the prism array. FIG. 12 is a schematic diagram showing an arrangement of real images and virtual images of pixels by the optical filter. FIG. 13 is a simulation result of a real image and a virtual image for the optical filter. FIG. 14 is a cross-sectional view of the optical filter. FIG. 15 is a schematic diagram showing the projected area of ​​a prism included in the optical filter. FIG. 16 is a simulation result of a real image and a virtual image when the ratio of the projected areas is different in the optical filter.10 is a simulation result of a real image and a virtual image when the ratio of the projected areas is equal in the optical filter. FIG. 11 is a schematic diagram showing the projected area of ​​a prism included in the optical filter. FIG. 12 is a perspective view of a prism included in the optical filter according to Configuration Example 3 of the present embodiment. FIG. 13 is a cross-sectional view of the prism. FIG. 14 is a schematic diagram of the optical filter. FIG. 15 is a perspective view of a prism array included in the optical filter. FIG. 16 is a plan view of the prism array. FIG. 17 is a schematic diagram showing an arrangement of real images and virtual images of pixels by the optical filter. FIG. 18 is a simulation result of a real image and a virtual image for the optical filter. FIG. 19 is a perspective view of a prism included in an optical filter according to Modification Example 1 of Configuration Example 3. FIG. 19 is a cross-sectional view of the prism. FIG. 19 is a perspective view of a prism array included in the optical filter. FIG. 19 is a simulation result of a real image and a virtual image for the optical filter. FIG. 19 is a perspective view of a prism included in an optical filter according to Modification Example 2 of Configuration Example 3. FIG. 19 is a cross-sectional view of the prism. FIG. 19 is a perspective view of a prism array included in the optical filter. FIG. 19 is a simulation result of a real image and a virtual image for the optical filter. FIG. 19 is a perspective view of a prism included in an optical filter according to Configuration Example 4 of the present embodiment. FIG. 19 is a cross-sectional view of the prism. FIG. 19 is a schematic diagram of the optical filter. 1 is a perspective view of a prism array included in the optical filter. FIG. 2 is a plan view of the prism array. FIG. 3 is a graph showing an example of the shape of an inclined surface included in the prism. FIG. 4 is a schematic view showing an arrangement of real images and virtual images of pixels by the optical filter. FIG. 5 is a simulation result of real images and virtual images for the optical filter. FIG. 6 is a schematic view of a prism included in an optical filter according to Configuration Example 5 of the present embodiment. FIG. 7 is a perspective view of the prism. FIG. 8 is a schematic view of a prism included in another optical filter according to Configuration Example 5 of the present embodiment. FIG. 9 is a perspective view of the prism. FIG. 10 is a simulation result of real images and virtual images for the optical filter. FIG. 11 is a perspective view of a prism included in an optical filter according to Modification Example 1 of Configuration Example 5. FIG. 12 is a simulation result of real images and virtual images for the optical filter. FIG. 13 is a perspective view of a prism included in an optical filter according to Modification Example 1 of Configuration Example 5. FIG. 14 is a simulation result of real images and virtual images for the optical filter.

[0024] [Configuration of Image Display Device] An image display device according to an embodiment of the present technology will be described. Fig. 1 is a schematic diagram of an image display device 100 according to this embodiment, and Fig. 2 is an enlarged view thereof. As shown in these figures, the image display device 100 includes an image display body 101, a spacer 102, and an optical filter 103. The image display device 100 is an image display device for virtual production, and is photographed by a photographing device 150 as shown in Fig. 1.

[0025] The image display 101 has a pixel group in which a plurality of pixels 104 are arranged as shown in Fig. 2, and generates an image. Each pixel 104 emits light of a single color or multiple colors, and is, for example, a micro LED (light-emitting diode). As shown in the figure, the pitch of the pixels 104 is defined as a pitch P Ｒ Pitch P Ｒ is, for example, 2.5 mm. There are no particular limitations on the specific configuration of the image display body 101. Hereinafter, directions parallel to the surface of the image display body 101 are referred to as the X direction and the Y direction, and a direction perpendicular to the X direction and the Y direction is referred to as the Z direction.

[0026] The spacer 102 is laminated on the image display 101 and defines the distance between the image display 101 and the optical filter 103. The spacer 102 is configured to transmit light emitted from the pixels 104, and is a plate made of a transparent optical resin such as acrylic. The spacer 102 may also be made of a transparent optical resin containing a diffusing material. As shown in FIG. 2 , the thickness (Z direction) of the spacer 102 is defined as thickness T. Thickness T is, for example, 2.3 mm.

[0027] The optical filter 103 is laminated on the side of the spacer 102 opposite to the image display body 101, and separates the rays of light incident from the image display body 101 through the spacer 102. Fig. 3 is a schematic diagram showing the separation of rays by the optical filter 103. As shown in the figure, when a ray L1 of light emitted from a pixel 104 enters the optical filter 103, the ray L1 is separated by the optical filter 103, and a ray L2 is generated.

[0028] In the figure, the extension of the light ray L2 toward the image display 101 is shown as a light ray L3. When viewed through the optical filter 103, the light ray L2 is reflected by the real image G of the pixel 104. Ｒ Instead, the virtual image G at the exit position of the light ray L3 Ｖ As shown in the figure, the angle formed by the light ray L2 with respect to the light ray L1 is taken as the separation angle θa. Although one pixel 104 is shown in FIG. 3, the same applies to the other pixels 104.

[0029] 4 is a schematic diagram of the image display device 100 at this time, viewed from the optical filter 103 side. Since the light beam is split into light beams L2 as described above, the real image G Ｒ is not visible, and each real image G Ｒ Four virtual images G around Ｖ In FIG. 4, a virtual image G Ｖ In this way, the optical filter 103 separates the light beams emitted from each pixel 104, increasing the apparent number of pixels. Ｖ Pitch P Ｖ is the real image G Ｒ Pitch P Ｒ Also, the virtual image G Ｖ The amount of light is divided into rays to form a real image G Ｒ As shown in FIG. 4, four virtual images G Ｖ When the virtual image G Ｖ The amount of light of the real image G Ｒ It becomes 1 / 4 of that.

[0030] 5 and 6 are schematic diagrams showing the effect of light beam separation. Fig. 5 is a schematic diagram showing pixels 121 of a general display, image pickup elements 122 of an image pickup device that photographs the display, and the amount of light received by each image pickup element 122. The pitch of the pixels 121 is defined as a pitch P Ｄ and the pitch of the image pickup element 122 is P ＣAs shown in the figure, when outgoing light 123 emitted from one pixel 121 is incident on one image sensor 122, the amount of light received by that image sensor 122 is 1. On the other hand, when outgoing light 123 from one pixel 121 is incident on the boundary between two image sensors 122, the amount of light received by each image sensor 122 is 0.5. Therefore, the amount of light received by each image sensor 122 is either 1 or 0.5, and this difference causes moiré.

[0031] 6, the light amount of each pixel 121 is set to 1 / 3 of the configuration of FIG. 5, and the pitch P Ｄ 6 is a schematic diagram showing a case where the number of pixels 121 into which the outgoing light 123 is incident on each image sensor 122 is increased and the amount of light received by each pixel 121 is small, so the amount of light received by each image sensor 122 is 0.83 or 0.67, and the difference in the amount of received light is reduced compared to the configuration in FIG. 5. For this reason, the configuration in FIG. 6 suppresses moire compared to the configuration in FIG. 5.

[0032] Here, as described above, the image display device 100 separates light rays using the optical filter 103, and four virtual images G are generated from one pixel 104 as shown in FIG. Ｖ is generated, it is equivalent to increasing the number of pixels 104, decreasing the pitch, and decreasing the amount of light in each pixel 104. Therefore, when the image display device 100 is photographed with the photographing device 150, it is possible to suppress moire that occurs in the photographing device 150.

[0033] The image display device 100 has the above-described configuration. Note that an anti-reflection sheet having a dielectric film or microstructures such as a moth-eye, an anti-glare sheet with a diffusion function, or the like may be provided on the surface of the optical filter 103. The configuration of the image display device 100 is not limited to that described above, and any device capable of displaying images and including at least the optical filter 103 may be used. The image display device 100 is not limited to that used for virtual production, and the present technology can be applied to any image display device that is capable of displaying images and is photographed by a photographing mechanism.

[0034] [Specific Configuration of Optical Filter] A specific configuration of the optical filter 103 will be described. Fig. 7 is a cross-sectional view of the optical filter 103. As shown in the figure, the optical filter 103 includes a first layer 111 and a second layer 112.

[0035] The first layer 111 has a first refractive index n １ The first layer 111 is provided with a prism array 113. The first layer 111 is made of an optical material such as glass or transparent resin. Fig. 8 is a perspective view of the prism array 113, and Fig. 9 is a plan view of the prism array 113. As shown in these figures, the prism array 113 is configured by arranging a plurality of prisms 114. In Fig. 9, one prism 114 is shown surrounded by a thick line.

[0036] Fig. 10 is a perspective view of one prism 114. As shown in the figure, the prism 114 has a quadrangular pyramid shape and four inclined surfaces 114a. As shown in Fig. 7, the first layer 111 has a light incident surface 115, which is the surface opposite to the prism array 113, and an interface surface 116, which is the surface opposite to the light incident surface 115 and is the surface of the prism array 113. Therefore, the interface surface 116 is made up of a plurality of inclined surfaces 114a. The light incident surface 115 is a plane parallel to the surface (X-Y plane) of the image display body 101.

[0037] As shown in FIG. 9, the prism arrangement angle θ ｈ is, for example, 45°. The period of the prisms 114, i.e., the prism pitch, is defined as the pitch P ａ Then, the pitch P ａ is, for example, 100 μm. ａ A pitch that does not cause diffraction is preferable, and a pitch of more than 25 μm is preferable.

[0038] The second layer 112 is deposited on the interface 116 and has a second refractive index n ２ The second layer 112 is made of an optical material such as glass or transparent resin. ２ is the first refractive index n １ The third refractive index n ３ or more refractive index (i.e., n １ >n ２ ≧n ３) The atmosphere refers to a gas such as air that exists around the optical filter 103. As shown in FIG. 7, the second layer 112 has a light exit surface, which is the surface opposite to the boundary surface 116. The light exit surface 117 is a plane parallel to the light incident surface 115 (X-Y plane).

[0039] 11 is a schematic diagram showing the inclination angle and critical angle of the inclined surface 114a that constitutes the boundary surface 116. As shown in the figure, a plane (XY plane) parallel to the light incident surface 115 is defined as plane F, and the angle of the inclined surface 114a with respect to plane F is defined as inclination angle θ Ｓ In the figure, a cross section (X-Z plane) perpendicular to the light incident surface 115 (X-Y plane) is shown, but the inclined surface 114a also has an inclination angle θ in the cross section (Y-Z plane) perpendicular to the cross section. Ｓ It has.

[0040] The critical angle of the boundary surface 116 is defined as the critical angle θ Ｃ The critical angle θ Ｃ is the angle at which light incident on the boundary surface 116 from the first layer 111 is totally reflected, and the first refractive index n １ and the second refractive index n ２ θ is expressed by the following (Equation 1). Ｃ = sin －１ (n ２ / n １ ) (Formula 1)

[0041] The optical filter 103 has an inclination angle θ Ｓ is the critical angle θ Ｃ Larger, i.e., θ Ｓ >θ Ｃ 12 to 15 are schematic diagrams illustrating this effect, showing a light ray L1 of light emitted from a pixel 104 and a light ray L2 generated when the light ray L1 is separated by the optical filter 103. FIG. 13 also shows a light ray L3 that is an extension of the light ray L2 toward the image display body 101. In FIGS. 12 and 13 , "portion A" denotes a portion of the optical filter 103 near a position perpendicular to the pixel 104 and the light incident surface 115 (Z direction), and "portion B" denotes a portion of the optical filter 103 separated from "portion A," i.e., a portion positioned diagonally from the pixel 104.

[0042] As shown in FIG. 14, in “part A”, the inclination angle θ Ｓ is the critical angle θ Ｃ Since the incident angle θ of the light ray L1 is larger than the incident angle θ of the light ray L1, １ is the critical angle θ Ｃ Therefore, the light ray L1 is totally reflected at the boundary surface 116. The light ray L1 is further refracted at the light emitting surface 117 and emitted as a light ray L2 from the light emitting surface 117. Since the light ray L1 is totally reflected at the boundary surface 116, the separation angle θ ａ becomes larger.

[0043] Also, as shown in FIG. 15, in “part B”, the incident angle θ １ is the critical angle θ Ｃ The angle of inclination θ becomes smaller than the angle of inclination θ, and the light ray L1 is refracted at the boundary surface 116. The light ray L1 is further refracted at the light emitting surface 117 and is emitted as a light ray L2 from the light emitting surface 117. Ｓ is large, the separation angle θ ａ becomes larger.

[0044] In this way, in the optical filter 103, the separation angle θ between the light beam L1 and the light beam L2 is ａ As a result, even if the thickness T of the spacer 102 is small, the real image G Ｒ and virtual image G Ｖ It is possible to increase the distance R

[0045] 16 is a schematic diagram showing the configuration of an optical filter 303 for comparison. The optical filter 303 has a first layer 311 and a second layer 312. The first layer 311 is provided with a prism array 313 in which a plurality of prisms 314 are arranged. The refractive index of the first layer 311 is a first refractive index n １ is the second refractive index n ２ Smaller (n １ <n ２ ), that is, the magnitude relationship of the refractive index is opposite to that of the optical filter 103 according to this embodiment.

[0046] In this case, the first layer 311 and the second layer 312 are a combination with a high Fresnel reflectance, and as shown in the figure, a light ray L4 that enters the optical filter 303 from the outside is reflected by the boundary surface 316 and becomes stray light before being emitted from the optical filter 303. Therefore, with this optical filter 303, external light such as illumination light and natural light is reflected by the optical filter 303, causing problems during shooting for virtual production, etc.

[0047] 17 is a schematic diagram showing the configuration of an optical filter 403 for comparison. The optical filter 403 has a first layer 411 and a second layer 412. The first layer 411 is provided with a prism array 413 in which a plurality of prisms 414 are arranged. The refractive index of the first layer 411 is a first refractive index n １ is the second refractive index n ２ Larger than (n １ >n ２ ), that is, the magnitude relationship of the refractive index is the same as that of the optical filter 103 according to this embodiment.

[0048] In this case, the first layer 411 and the second layer 412 do not have a combination with a high Fresnel reflectance, so that the reflection of external light as in the optical filter 303 does not become a problem. １ is the second refractive index n ２ If it is larger, the angle of separation θ ａ To increase the tilt angle θ Ｓ However, in this case, as shown in FIG. ３ is the critical angle θ of the light emitting surface 417 Ｍ A light ray L5 that is larger than the incident light ray L1 and is totally reflected by the light exit surface 417 is generated.

[0049] If this total reflection is not caused, the tilt angle θ Ｓ cannot be increased beyond a certain level, and the separation angle θ ａ Separation angle θ ａ If the thickness T of the spacer (see Figure 2) is not increased, the real image G Ｒ and virtual image G Ｖ The distance R between the real image G Ｒ and virtual image G ＶWhen the distance R is insufficient, the real image G Ｒ and virtual image G Ｖ As shown in the figure, if the distance R is insufficient, the virtual image G Ｖ However, increasing the thickness T of the spacer increases the weight of the image display device and reduces the ease of holding the optical filter 403 and the installation of the image display device.

[0050] In contrast, in the optical filter 103 according to this embodiment, the refractive index of the first layer 111 is the first refractive index n １ is the refractive index of the second layer 112, ２ greater than (n １ >n ２ ), so there is no problem with external light reflection. In addition, in the optical filter 103, the light is split by a separation angle θ at part A due to total reflection and at part B due to refraction. ａ (See FIG. 13 ), and even if the thickness T of the spacer 102 is small, the real image G Ｒ and virtual image G Ｖ It is possible to increase the distance R.

[0051] In addition, the optical filter 103 does not use the diffraction effect to separate light beams, so there is no degradation in image quality due to a loss of color balance. Therefore, the optical filter 103 according to this embodiment can suppress moiré without impairing image quality, and has a configuration suitable for thinning.

[0052] The optical filter 103 has an inclination angle θ Ｓ is the critical angle θ Ｃ The inclination angle θ 116 does not have to be larger than the inclination angle θ 216 . Ｓ is the critical angle θ Ｃ It may be larger, as will be explained in more detail below.

[0053] [Details of the Inclination Angle] As described above, in the optical filter 103, the inclination angle θ of the boundary surface 116 Ｓ is the critical angle θ Ｃ Here, the inclination angle θ Ｓ is the critical angle θ ＣIt is preferable that the angle θ is larger than 1 / 2 and satisfies the following (Equation 2): Ｓ ≧99.296ΔN+62.034 (Formula 2) ΔN=(n １ -n ２ ) (n ２ -n ３ )

[0054] Inclination angle θ Ｓ satisfies the above (Equation 2), it is possible to prevent reflection of light by the light exit surface 117. Figures 19 and 20 are schematic diagrams showing reflection of light by the light exit surface 117, and show a light ray L6 reflected by the light exit surface 117. As shown in Figure 20, the incident angle of the light ray L1 reflected by the boundary surface 116 with respect to the light exit surface 117 is defined as an incident angle θ Ｏ Let's say.

[0055] This incident angle θ Ｏ is the critical angle θ of the light emitting surface 117 Ｍ , the light ray L1 is totally reflected by the light exit surface 117 and travels toward the light incident surface 115 as shown in the figure. If total reflection occurs in the region of the boundary surface 116 where the light ray L1 is incident, as shown by the broken line, half of the light ray L1 incident on one prism 114 will not be emitted from the light exit surface 117. Therefore, when this total reflection occurs, the virtual image G Ｖ The amount of light is insufficient, and the moire reduction effect is reduced.

[0056] In addition, the critical angle θ Ｍ is the angle at which light incident on the light exit surface 117 from the second layer 112 is totally reflected, and the second refractive index n ２ and the third refractive index n ３ θ is expressed by the following (Equation 3) Ｍ = sin －１ (n ３ / n ２ ) (Formula 3)

[0057] FIG. 21 shows the incident angle θ Ｌ Tilt angle θ Ｓ and the angle of incidence θ Ｏ 10 is a graph showing the relationship between the incident angle θ Ｌ is the angle of incidence of the light ray L1 with respect to the light incident surface 115 as shown in FIG. 20. In FIG. 21, the first refractive index n １ is 1.65 (high refractive index resin), the second refractive index n２ is 1.41 (low refractive index resin), the third refractive index n ３ is 1.00 (air), the critical angle θ Ｍ (45.2°).

[0058] As shown in FIG. 21, the incident angle θ Ｌ When the inclination angle θ is between -40° and -20°, Ｓ Regardless of the incident angle θ Ｏ is the critical angle θ Ｍ is smaller than the incident angle θ 2 , and total reflection does not occur at the light exit surface 117. Ｌ When the angle is -10°, the tilt angle θ Ｓ is smaller than the angle K, the incident angle θ Ｏ is the critical angle θ Ｍ , and total reflection occurs at the light exit surface 117 .

[0059] The angle K is the incident angle θ Ｏ is the critical angle θ Ｍ The tilt angle θ S The incident angle θ of the plot with the largest Ｏ is the critical angle θ Ｍ The tilt angle θ S In this example, the tilt angle θ is 71.8°. Ｓ is smaller than the angle K, the incident angle θ Ｏ is the critical angle θ Ｍ , and total reflection occurs at the light exit surface 117. Ｓ By making the angle K or more, the incident angle θ Ｌ It is possible to prevent the light ray L1 at an angle of −10° from being totally reflected on the light exit surface 117.

[0060] In addition, the incident angle θ Ｌ Even when the inclination angle θ is between 0° and 40°, Ｓ If the angle is equal to or greater than K, the incident angle θ Ｏ is the critical angle θ Ｍ Therefore, the inclination angle θ Ｓ By setting the angle to be equal to or larger than the angle K, it is possible to prevent the total reflection of the light ray L1 from occurring on the light exit surface 117.

[0061] FIG. 22 shows the first refractive index n １: 1.55 to 1.75, second refractive index n ２ : 1.00 to 51, third refractive index n ３ Calculations were performed in the same manner as in the above example using combinations selected from the refractive index range of 1.00 to 1.00, and the angle K was plotted against ΔN. ΔN is expressed by the following (Equation 4): ΔN=(n １ -n ２ ) (n ２ -n ３ )) (Formula 4)

[0062] The plot shown in Figure 22 shows an approximate line obtained by the least squares method. This approximate line is expressed by the function shown in the following (Equation 5): θ Ｓ =99.296ΔN+62.034 (Formula 5)

[0063] Therefore, the tilt angle θ Ｓ By setting the range shown in the above (Equation 2), it is possible to prevent total reflection of the light ray L1 at the light exit surface 117, prevent a decrease in the amount of light due to total reflection, and obtain a high moire reduction effect.

[0064] [Regarding Prism Pitch] As described above, the pitch P ａ (See FIG. 9) is preferably a pitch that does not cause diffraction, and specifically, a pitch larger than 25 μm is preferable. ａ 1 is a graph showing the relationship between the pitch P ａ If the pitch P is 25 μm or less, multiple high-order diffracted light beams are generated, resulting in deviation from the desired refraction angle. ａ If the pitch P is greater than 25 μm, the effect of diffraction does not occur. ａ By making the diffraction angle larger than 25 μm, it is possible to prevent deterioration in image quality, such as loss of color balance, due to diffraction.

[0065] [Various Configurations of the Optical Device] As described above, the optical filter 103 has an inclination angle θ Ｓ is the critical angle θ of the boundary surface 116 ＣThe shape of the prism 114 is not limited to the above as long as it is larger. Various configuration examples of the optical filter 103 will be described below. Note that the following will focus on differences from the configurations already described, and will omit a description of the same points.

[0066] {Configuration Example 1} As described above, the prism 114 can be formed in a quadrangular pyramid shape (see FIG. 10). As for the configuration of each layer, for example, the first layer 111 is made of a transparent optical resin and has a first refractive index n １ is 1.65, the second layer 112 is made of a transparent optical resin, and the second refractive index n ２ is 1.41, the atmosphere is air, and the third refractive index n ３ can be set to 1.00. In this case, the critical angle θ of the boundary surface 116 Ｃ is 58.7°.

[0067] The inclination angle θ of the inclined surface 114a Ｓ is 72°, and the prism arrangement angle θ ｈ (See FIG. 9) can be set to 45°, width W to 100 μm, and height H to 154 μm. Ｒ (see FIG. 2) is 2.5 mm, and the spacer 102 is made of acrylic and has a thickness T of 2.3 mm. Ｓ satisfies the above (Equation 2).

[0068] When a light ray L1 is incident on the optical filter 103, the light ray L1 emitted from one pixel 104 is split by the four slopes 114a of the quadrangular pyramid. Ｒ is not formed, and four virtual images G Ｖ The virtual image distance D Ｖ is 0.884 mm, virtual image G Ｖ Pitch P Ｖ is the real image G Ｒ Pitch P Ｒ This is half of the above, or 1.25 mm.

[0069] 24 shows the results of a simulation in which the pixels 104 are made to emit light with the optical filter 103 removed from the image display device 100. The pixels 104 are represented by white dots, and their pitch P Ｒ25 shows the results of a simulation in which the pixel 104 is caused to emit light in the image display device 100 equipped with the optical filter 103 having the configuration of Configuration Example 1. In the figure, the real image G Ｒ is not visible, and the virtual image G Ｖ is represented by a white dot. Ｖ Pitch P Ｖ is 1.25 mm.

[0070] For comparison, FIG. 26 shows the tilt angle θ Ｓ is 58°, that is, the inclination angle θ Ｓ is the critical angle θ Ｃ The figure shows the simulation results for an optical filter with a virtual image G Ｖ is represented by a white dot, but in this configuration, the virtual image G Ｖ The distance between the two lenses is insufficient, and the moire reduction effect is reduced. Ｖ To achieve uniform spacing, the spacer thickness must be about 3.85 mm, ie, 1.75 times the thickness.

[0071] In contrast, in the above-described configuration example 1, the inclination angle θ Ｓ The critical angle θ Ｃ By making it larger, even if the thickness of the spacer 102 is as thin as 2.3 mm, the virtual image G Ｖ The prism 114 is not limited to a quadrangular pyramid shape, but may be an n-sided pyramid shape (n is a natural number of 3 or more).

[0072] {Configuration Example 2} The prisms 114 may have a truncated quadrangular pyramid shape. Fig. 27 is a perspective view of a prism 114 having a truncated quadrangular pyramid shape, and Fig. 28 is a cross-sectional view of an optical filter 103 including a prism array 113 in which the prisms 114 are arranged. Fig. 29 is a perspective view of the prism array 113, and Fig. 30 is a plan view of the prism array 113. In Fig. 30, one prism 114 is indicated by a bold line surrounding it.

[0073] 27, the prism 114 has four inclined surfaces 114a and one parallel surface 114b. Each inclined surface 114a is inclined with respect to a plane F (XY plane) parallel to the light incident surface 115, and the angle of the inclined surface 114a with respect to the plane F is an inclination angle θ Ｓ In the figure, a cross section (X-Z plane) perpendicular to the light incident surface 115 (X-Y plane) is shown, but the inclined surface 114a also has an inclination angle θ in the cross section (Y-Z plane) perpendicular to the cross section. Ｓ The parallel surface 114b is a plane parallel to the plane F (XY plane).

[0074] As for the configuration of each layer, for example, the first layer 111 is made of a transparent optical resin and has a first refractive index n １ is 1.65, the second layer 112 is made of a transparent optical resin, and the second refractive index n ２ is 1.41, the atmosphere is air, and the third refractive index n ３ can be set to 1.00. In this case, the critical angle θ of the boundary surface 116 Ｃ is 58.7°.

[0075] The inclination angle θ of the inclined surface 114a Ｓ The pitch P of the pixel 104 can be set to 78°, the prism arrangement angle θh (see FIG. 30) to 26.6°, the width W1 to 100 μm, the width W2 to 44 μm, and the height H to 130 μm. Ｒ (see FIG. 2) is 2.5 mm, and the spacer 102 is made of acrylic and has a thickness T of 1.95 mm. Ｓ is the critical angle θ Ｃ and satisfies the above (Equation 2).

[0076] 31 is a schematic diagram of the image display device 100, in which the pixels 104 are caused to emit light, as viewed from the optical filter 103 side. When a light ray L1 is incident on the optical filter 103, a part of the light ray L1 emitted from one pixel 104 passes through the parallel surface 114b, and a real image G is formed as shown in FIG. Ｒ The other part of the light ray L1 is separated by the four slopes 114a of the quadrangular pyramid, and forms a real image G Ｒ Four virtual images G around Ｖ The virtual image distance D Ｖ is 1.12 mm, virtual image GＶ Pitch P Ｖ is 1.12 mm.

[0077] According to this configuration, the optical filter 103 reduces the virtual image G Ｖ In addition to the real image G Ｒ Since the image of the pixel 104 captured by the image capturing device 150 (see FIG. 1) is also formed, the number of images of the pixel 104 captured by the image capturing device 150 (see FIG. 1) is further increased, and a greater moire reduction effect is obtained. Furthermore, the aspect ratio (height H / width W1) of the prism 114 can be reduced, and the difficulty of manufacturing the optical filter 103 can be reduced.

[0078] 32 shows the simulation results for the optical filter 103 having the configuration of Configuration Example 2. In the figure, the real image G Ｒ and virtual image G Ｖ is represented by a white dot. Ｖ Pitch P Ｖ is 1.12 mm.

[0079] Prisms 114 having a truncated quadrangular pyramid shape may have a plane between adjacent prisms 114. Fig. 33 is a schematic diagram showing a prism 114 having a parallel surface 114c between adjacent prisms 114. The parallel surface 114c is a plane parallel to plane F (XY plane).

[0080] In this configuration, when a light ray L1 is incident on the optical filter 103, a part of the light ray L1 emitted from one pixel 104 passes through the parallel surface 114b and the parallel surface 114c, and a real image G is formed as shown in FIG. Ｒ The other part of the light ray L1 is separated by the four slopes 114a of the quadrangular pyramid, and forms a real image G Ｒ Four virtual images G around Ｖ Form.

[0081] Furthermore, the prism 114 is not limited to a quadrangular pyramid shape, but may also have an n-sided pyramid shape (n is a natural number of 3 or more).

[0082] (Projection Area in Configuration Example 2) In Configuration Example 2, the projection areas of the inclined surfaces 114a and the parallel surfaces 114b can be set as follows. FIG. 34 shows the projection area S ａand the projected area S of the parallel surface 114b ｂ As shown in the figure, these projected areas are areas obtained by projecting the inclined surface 114 a and the parallel surface 114 b onto a plane F, in other words, areas when the inclined surface 114 a and the parallel surface 114 b are viewed from a direction perpendicular to the plane F (Z direction).

[0083] Here, the projected area S ａ is the projected area S ｂ That is, it is preferable that the following (Formula 6) is satisfied: S ａ / S ｂ ≒1 (Formula 6)

[0084] As a result, the real image G Ｒ and virtual image G Ｖ The amount of light becomes equal to that of the real image G, and the moire suppression effect can be improved. Ｒ and virtual image G Ｖ On the other hand, Figure 36 shows the simulation results when (Equation 6) is satisfied. As shown in the figure, the brightness of the real image G Ｒ and virtual image G Ｖ The brightness is uniform.

[0085] 33, when a parallel surface 114c is provided between adjacent prisms 114, the projected area of ​​the inclined surface 114a, the parallel surface 114b, and the plane 114c can be as follows. ａ、 Projected area S of the parallel surface 114b ｂ and the projected area S of the parallel surface 114c ｃ FIG.

[0086] In this case, the projected area S ａ is the projected area S ｂ and the projected area S ｃ It is preferable that the sum of S is equal to or substantially equal to the sum of S. ａ / (S ｂ +S ｃ )≒1 (Equation 7)

[0087] When the above (Equation 7) is satisfied, the real image G Ｒ and virtual image G Ｖ Similarly, when the prism 114 has an n-sided pyramid shape (n is a natural number of 3 or more), if the above (Equation 6) or (Equation 7) is satisfied, the real image G Ｒ and virtual image G Ｖ The amount of light can be made equivalent.

[0088] {Configuration Example 3} Prisms 114 may have inclined surfaces with different inclination angles. Fig. 38 is a perspective view of a prism 114 having inclined surfaces with different inclination angles, and Fig. 39 is a cross-sectional view thereof. Fig. 40 is a cross-sectional view of an optical filter 103 including a prism array 113 in which such prisms 114 are arranged. Fig. 41 is a perspective view of the prism array 113, and Fig. 42 is a plan view of the prism array 113. In Fig. 42, one prism 114 is indicated by a bold line surrounding it.

[0089] 38 to 40, the prism 114 has four inclined surfaces 114a and one parallel surface 114b. Each inclined surface 114a has a first inclined surface 114d on the light incident surface 115 side and a second inclined surface 114e on the light exit surface 117 side. Each first inclined surface 114d is inclined with respect to a plane F (XY plane) parallel to the light incident surface 115, and the angle of the first inclined surface 114d with respect to the plane F is called an inclination angle θ Ｓ１ Let's say.

[0090] Each second inclined surface 114e is inclined with respect to the plane F (XY plane), and the angle of the second inclined surface 114e with respect to the plane F is defined as an inclination angle θ Ｓ２ The inclination angle θ Ｓ１ and the tilt angle θ Ｓ２ and at least one of the angles is different from the critical angle θ of the interface 116. Ｃ 40 shows a cross section (XZ plane) perpendicular to the light incident surface 115 (XY plane), but the first inclined surface 114d also has a tilt angle θ Ｓ１ The second inclined surface 114e has an inclination angle θ Ｓ２ The parallel surface 114b is a plane parallel to the plane F (XY plane).

[0091] Specifically, as shown in FIG. 39, the prism 114 has a truncated pyramid 152 provided on a truncated pyramid 151, and the angle θ between the first inclined surface 114d and the second inclined surface 114e is Ｅ can be configured so that the angle is an obtuse angle.

[0092] As for the configuration of each layer, for example, the first layer 111 is made of a transparent optical resin and has a first refractive index n １ is 1.75, the second layer 112 is made of a transparent optical resin, and the second refractive index n ２ is 1.31, the atmosphere is air, and the third refractive index n ３ can be set to 1.00. In this case, the critical angle θ of the boundary surface 116 Ｃ is 48.5°.

[0093] The inclination angle θ of the first inclined surface 114d Ｓ１ is 79°, and the inclination angle θ of the second inclined surface 114e is Ｓ２ is the 55° prism arrangement angle θ ｈ (see FIG. 42) can be set to 26.6°, width W1 to 100 μm, width W2 to 28 μm, height H1 to 103 μm, and height H2 to 72 μm. Ｒ (see FIG. 2) is 2.5 mm, and the spacer 102 is made of acrylic and has a thickness T of 1.75 mm. Ｓ１ and inclination angle θ Ｓ２ is the critical angle θ Ｃ The larger the angle, the tilt angle θ Ｓ１ satisfies the above (Equation 2).

[0094] 43 is a schematic diagram of the image display device 100, in which the pixels 104 are caused to emit light, viewed from the optical filter 103 side. When a light ray L1 is incident on the optical filter 103, a part of the light ray L1 emitted from one pixel 104 passes through the parallel surface 114b, and a real image G is formed as shown in FIG. Ｒ The other part of the light ray L1 is separated by the four first inclined surfaces 114d and the four second inclined surfaces 114e, forming a real image G Ｒ Eight virtual images G around Ｖ The virtual image distance D Ｖ１ is 0.7 mm, virtual image distance D Ｖ２ is 1.4 mm, virtual image G ＶThe pitch is a composite pitch of 0.7 mm and 1.4 mm.

[0095] According to this configuration, by providing the first inclined surface 114d and the second inclined surface 114e on the inclined surface 114a, the virtual image G Ｖ Since the number of the inclined surfaces 114a increases, the number of images of the pixels 104 captured by the image capturing device 150 (see FIG. 1) further increases, resulting in a greater moire reduction effect. Furthermore, the aspect ratio (height H1 / width W1) of the prism 14 can be reduced, making it possible to reduce the difficulty of manufacturing the optical filter 103. The number of the inclined surfaces 114a is not limited to four, but may be three or more. Furthermore, when one inclined surface 114a has an inclination angle θ Ｓ It may have three or more slopes with different slopes.

[0096] 44 shows the simulation results for the optical filter 103 having the configuration of Configuration Example 3. In the figure, the real image G Ｒ and virtual image G Ｖ is represented by a white dot. Ｖ The pitch is a composite pitch of 0.7 mm and 1.4 mm.

[0097] (Modification of Configuration Example 3) The shape of the prism 114 in Configuration Example 3 can be other shapes. Fig. 45 is a perspective view of the prism 114 according to Modification Example 1, and Fig. 46 is a cross-sectional view thereof. Fig. 47 is a perspective view of a prism array 113 made up of this prism 114. As shown in these figures, the prism 114 has a shape in which the truncated quadrangular pyramid 154 has been removed from the truncated quadrangular pyramid 153, and the angle θ between the first inclined surface 114d and the second inclined surface 114e is Ｅ 48 shows the results of a simulation of the optical filter 103 having this configuration. In the figure, the real image G Ｒ and virtual image G Ｖ are represented by white dots.

[0098] Fig. 49 is a perspective view of a prism 114 according to Modification 2, and Fig. 50 is its cross-sectional view. Fig. 51 is a perspective view of a prism array 113 made up of this prism 114. As shown in these figures, the prism 114 has a shape in which a truncated quadrangular pyramid 156 has been removed from a truncated quadrangular pyramid 155. The truncated quadrangular pyramid 156 is rotated by 45° relative to the truncated quadrangular pyramid 155 in a plane (X-Y plane) parallel to the light incident surface 115. The angle θ between the first inclined surface 114d and the second inclined surface 114e is Ｅ 52 shows the results of a simulation of the optical filter 103 having this configuration. In the figure, the real image G Ｒ and virtual image G Ｖ are represented by white dots.

[0099] {Configuration Example 4} The prism 114 may have a curved inclined surface. Fig. 53 is a perspective view of a prism 114 having a curved inclined surface, and Fig. 54 is a cross-sectional view of this prism 114. Fig. 55 is a cross-sectional view of an optical filter 103 including a prism array 113 in which these prisms 114 are arranged. Fig. 56 is a perspective view of the prism array 113, and Fig. 57 is a plan view of the prism array 113. In Fig. 57, one prism 114 is shown surrounded by a thick line.

[0100] As shown in Figures 53 to 56, the prism 114 has four curved inclined surfaces 114a and one parallel surface 114b. Each inclined surface 114a is inclined with respect to a plane F (X-Y plane) parallel to the light incident surface 115, and the inclination with respect to plane F becomes gradually gentler as the distance from the light incident surface 115 increases. Figure 58 is a graph showing an example of the shape of the inclined surfaces 114a, plotting the width (X direction or Y direction) against the height (height from the parallel surface 114b, Z direction) of the prism 114. As shown in the figure, the inclined surfaces 114a can be parabolic. Alternatively, the inclined surfaces 114a may be curved surfaces of other shapes, such as hemispherical.

[0101] As shown in FIG. 54, the angle of the inclined surface 114a with respect to the plane F at each position is defined as an inclination angle θ Ｓ Then, the inclination angle θ Ｓbecomes gradually smaller as it becomes farther away from the light incident surface 115. In the figure, a cross section (X-Z plane) perpendicular to the light incident surface 115 (X-Y plane) is shown, but the cross section (Y-Z plane) perpendicular to this also has the same inclination angle θ Ｓ The inclination angle θ at least at a part of the inclined surface 114a becomes gradually smaller as the inclination angle θ increases from the light incident surface 115. Ｓ is the critical angle θ of the boundary surface 116 Ｃ The parallel surface 114b is a plane parallel to the plane F (XY plane).

[0102] As for the configuration of each layer, for example, the first layer 111 is made of a transparent optical resin and has a first refractive index n １ is 1.75, the second layer 112 is made of a transparent optical resin, and the second refractive index n ２ is 1.31, the atmosphere is air, and the third refractive index n ３ can be set to 1.00. In this case, the critical angle θ of the boundary surface 116 Ｃ is 48.5°.

[0103] In addition, the prism arrangement angle θ ｈ (See FIG. 57) can be set to 26.6°, width W1 to 100 μm, width W2 to 12 μm, and height H to 150 μm. Ｒ The spacer 102 is made of acrylic and has a thickness T of 1.75 mm. Ｓ is the critical angle θ Ｃ The inclination angle θ at some positions is larger than the angle Ｓ satisfies the above (Equation 2).

[0104] 59 is a schematic diagram of the image display device 100, in which the pixels 104 are caused to emit light, as viewed from the optical filter 103 side. When a light ray L1 is incident on the optical filter 103, a part of the light ray L1 emitted from one pixel 104 passes through the parallel surface 114b, and a real image G is formed as shown in FIG. Ｒ The other part of the light ray L1 is separated by the four slopes 114a and forms a real image G Ｒ Four virtual images G around Ｖ At this time, since the inclined surface 114a is a curved surface, the virtual image GＶ is the real image G Ｒ The virtual image distance D is a band-like shape extending in one direction with the virtual image distance D as the center. Ｖ is 1.12 mm.

[0105] According to this configuration, the band-shaped virtual image G Ｖ is formed, the virtual image G Ｖ The uniformity of the pixel 104 increases, and a greater moire reduction effect can be obtained. The number of slopes 114a is not limited to four, but may be three or more. FIG. 60 shows the simulation results for the optical filter 103 having the configuration of the fourth configuration example. In the figure, the real image G Ｒ and virtual image G Ｖ is represented by a white dot. Ｖ The pitch of the virtual image G Ｖ The parallel surface 114b is not necessarily provided. In this case, the real image G Ｒ is not formed, and a band-shaped virtual image G Ｖ Only the nucleus is formed.

[0106] {Configuration Example 5} The prism 114 may be divided into a plurality of parts. Fig. 61 is a schematic diagram showing the division of the prism 114, and the prism 114 shown in the lower part of the figure is obtained by dividing the prism 114 shown in the upper part of the figure. Fig. 62 is a perspective view of this divided prism 114. Fig. 63 is a schematic diagram showing the division of another prism 114, and the prism 114 shown in the lower part of the figure is obtained by dividing the prism 114 shown in the upper part of the figure. Fig. 64 is a perspective view of this divided prism 114.

[0107] As shown in these figures, the prism 114 can be divided while maintaining the relationship between the inclined surfaces 114a and the parallel surfaces 114b. This makes it possible to reduce the height H of the prism 114 while maintaining its functionality, thereby reducing the aspect ratio (H / W) of the prism 114. For example, if the height H before division is 100 μm, the height H after division can be set to 50 μm. By reducing the aspect ratio of the prism 114 and designing the structure in consideration of the processing constraints of photolithography exposure and mold machining, manufacturability can be improved.

[0108] FIG. 65 shows the simulation results for the optical filter 103 having the prism 114 shown in FIG. 64, and shows the real image G Ｒ and virtual image G Ｖ is represented by white dots. When this simulation result is compared with the simulation result of the prism 114 before division (see FIG. 44), the real image G Ｒ and virtual image G Ｖ The arrangement is equivalent.

[0109] (Modification of Configuration Example 5) The division of the prism 114 is not limited to the above. Fig. 66 is a perspective view of the prism 114 according to Modification Example 1 of Configuration Example 5. Fig. 67 shows the simulation results for the optical filter 103 having this prism 114, and shows the real image G of the pixel 104. Ｒ and virtual image G Ｖ As shown in the figure, the prism 114 generates one real image G for one pixel 104. Ｒ and eight virtual images G Ｖ can be generated.

[0110] Fig. 68 is a perspective view of a prism 114 having yet another configuration. Fig. 69 shows the results of a simulation of the optical filter 103 having this prism 114, and shows the real image G Ｒ and virtual image G Ｖ As shown in the figure, the prism 114 generates one real image G for one pixel 104. Ｒ and 12 virtual images G Ｖ In addition, the prism 114 can be divided in various ways while maintaining the relationship between the inclined surface 114a and the parallel surface 114b.

[0111] [About the present disclosure] The effects described in this disclosure are merely examples and are not limiting, and other effects may also be present. The description of multiple effects does not necessarily mean that these effects are exhibited simultaneously. It means that at least one of the effects described above can be obtained depending on the conditions, etc., and effects not described in this disclosure may also be exhibited. Furthermore, it is possible to combine at least two of the characteristic features described in this disclosure.

[0112] The present technology can also be configured as follows.

[0113] (1) An optical filter comprising: a first layer having a first refractive index and including a prism array in which a plurality of prisms are arranged, the first layer having a light incident surface that is the surface opposite to the prism array, and a boundary surface that is the surface opposite to the light incident surface and is the surface of the prism array, wherein, when the angle formed by the boundary surface with the light incident surface is defined as an inclination angle, the inclination angle of at least a portion of the boundary surface is larger than a critical angle of the boundary surface; and a second layer stacked on the boundary surface, having a second refractive index and including a light exit surface that is the surface opposite to the boundary surface, the second refractive index being smaller than the first refractive index and equal to or greater than a third refractive index that is the refractive index of the atmosphere. (2) The optical filter according to (1), wherein the prism array is configured not to generate diffraction. (3) The optical filter according to (2), wherein the prism array has a prism pitch greater than 25 μm. (4) The optical filter according to any one of (1) to (3) above, wherein the boundary surface is composed of an inclined surface that is inclined with respect to the light incident surface and the inclination angle is greater than the critical angle. (5) The optical filter according to (4) above, wherein each prism that constitutes the prism array is composed of a plurality of the inclined surfaces, and the inclined surfaces are flat. (6) The optical filter according to (5) above, wherein the prism has an n-sided pyramid shape, where n is a natural number greater than or equal to 3. (7) The optical filter according to (4) above, wherein each prism that constitutes the prism array is composed of a plurality of the inclined surfaces, and the inclined surfaces are curved surfaces. (8) The optical filter according to any one of (1) to (3) above, wherein the boundary surface is composed of an inclined surface that is inclined with respect to the light incident surface and the inclination angle is greater than the critical angle, and a parallel surface that is parallel to the light incident surface. (9) The optical filter according to (8) above, wherein each prism constituting the prism array is composed of a plurality of the inclined surfaces and the parallel surfaces, and the inclined surfaces are flat surfaces.(10) The optical filter according to (9) above, wherein the prism has an n-sided pyramidal truncated shape, where n is a natural number equal to or greater than 3. (11) The optical filter according to (8) above, wherein each prism constituting the prism array is composed of a plurality of the inclined surfaces and the parallel surfaces, and the inclined surfaces are curved. (12) The optical filter according to (8) above, wherein, in each prism, the projected area of ​​the inclined surface on a plane parallel to the light incident surface is the same as the projected area of ​​the parallel surface on a plane parallel to the light incident surface. (13) The optical filter according to (1) above, wherein the boundary surface has a first inclined surface inclined with respect to the light incident surface, the inclination angle of which is a first angle, and a second inclined surface inclined with respect to the light incident surface, the inclination angle of which is a second angle different from the first angle, and at least one of the first angle and the second angle is greater than the critical angle. (14) The optical filter according to any one of (1) to (13) above, wherein the tilt angle is θ. Ｓ , the first refractive index is n １ , the second refractive index is n ２ , the third refractive index is n ３ Then, the optical filter satisfies the following (Equation 1). θ Ｓ [°] ≥ 99.296 · ΔN + 62.034 (Equation 1) where ΔN = (n １ -n ２ ) (n ２ -n ３(15) The optical filter according to any one of (1) to (14) above, wherein each prism constituting the prism array is divided into a plurality of portions. (16) An image display device comprising: an image display having a pixel group in which a plurality of pixels are arranged; a spacer laminated on the image display; and an optical filter laminated on the side of the spacer opposite to the image display, the optical filter having a first refractive index and a prism array in which a plurality of prisms are arranged, the optical filter having a light incident surface that is the surface opposite to the prism array and a boundary surface that is the surface opposite to the light incident surface and is the surface of the prism array, wherein, when an angle that the boundary surface makes with the light incident surface is an inclination angle, at least a part of the boundary surface has the inclination angle larger than a critical angle of the boundary surface; and a second layer laminated on the boundary surface, having a second refractive index, and having a light exit surface that is the surface opposite to the boundary surface, wherein the second refractive index is smaller than the first refractive index and is equal to or greater than a third refractive index that is the refractive index of the atmosphere, the optical filter being arranged so that the light incident surface faces the spacer, and light emitted from each pixel of the pixel group is incident on the light incident surface via the spacer.

[0114] REFERENCE SIGNS LIST 100...Image display device 101...Image display body 102...Spacer 103...Optical filter 104...Pixel 111...First layer 112...Second layer 113...Prism array 114...Prism 114a...Inclined surface 114b...Parallel surface 114c...Parallel surface 114d...First inclined surface 114e...Second inclined surface 115...Light incident surface 116...Boundary surface 117...Light exit surface

Claims

1. An optical filter comprising: a first layer having a first refractive index, comprising a prism array having a plurality of prisms arranged thereon, a light incident surface which is the surface opposite to the prism array, and a boundary surface which is the surface of the prism array opposite to the light incident surface, wherein, assuming that the angle which the boundary surface makes with the light incident surface is an inclination angle, at least a portion of the boundary surface has an inclination angle larger than a critical angle of the boundary surface; and a second layer laminated on the boundary surface, having a second refractive index, comprising a light exit surface which is the surface opposite to the boundary surface, wherein the second refractive index is smaller than the first refractive index and is equal to or greater than a third refractive index which is the refractive index of the atmosphere.

2. An optical filter according to claim 1, wherein said prism array is configured so as not to cause diffraction.

3. An optical filter according to claim 2, wherein the prism array has a prism pitch of greater than 25 μm.

4. An optical filter according to claim 1, wherein the boundary surface is configured as an inclined surface that is inclined with respect to the light incidence surface, the inclination angle being larger than the critical angle.

5. An optical filter according to claim 4, wherein each prism constituting said prism array is composed of a plurality of said inclined surfaces, and said inclined surfaces are flat surfaces.

6. An optical filter according to claim 5, wherein the prism has an n-sided pyramid shape, n being a natural number of 3 or more.

7. An optical filter according to claim 4, wherein each prism constituting said prism array is composed of a plurality of said inclined surfaces, and said inclined surfaces are curved surfaces.

8. An optical filter according to claim 1, wherein the boundary surface is composed of an inclined surface that is inclined with respect to the light incident surface, the inclination angle of which is greater than the critical angle, and a parallel surface that is parallel to the light incident surface.

9. An optical filter according to claim 8, wherein each prism constituting said prism array is composed of a plurality of said inclined surfaces and said parallel surfaces, and said inclined surfaces are flat surfaces.

10. The optical filter according to claim 9, wherein the prism has an n-sided pyramid shape, n being a natural number of 3 or more.

11. An optical filter according to claim 8, wherein each prism constituting said prism array is composed of a plurality of said inclined surfaces and said parallel surfaces, and said inclined surfaces are curved surfaces.

12. An optical filter according to claim 8, wherein in each of the prisms, the projected area of ​​each of the inclined surfaces onto a plane parallel to the light incident surface is equal to the projected area of ​​each of the parallel surfaces onto a plane parallel to the light incident surface.

13. An optical filter according to claim 1, wherein the boundary surface has a first inclined surface inclined with respect to the light incident surface, the inclination angle being a first angle, and a second inclined surface inclined with respect to the light incident surface, the inclination angle being a second angle different from the first angle, and at least one of the first angle and the second angle is larger than the critical angle.

14. The optical filter according to claim 1, wherein the inclination angle is θ Ｓ , the first refractive index is n １ , the second refractive index is n ２ , the third refractive index is n ３ Then, the optical filter satisfies the following (Equation 1). θ Ｓ [°] ≧ 99.296 · ΔN + 62.034 (Formula 1) where ΔN = (n １ -n ２ ) (n ２ -n ３ ) 15. An optical filter according to claim 1, wherein each prism constituting said prism array is divided into a plurality of portions.

16. An image display device comprising: an image display having a pixel group in which a plurality of pixels are arranged; a spacer laminated on the image display; and an optical filter laminated on the side of the spacer opposite to the image display, the optical filter having a first refractive index and a prism array in which a plurality of prisms are arranged, the optical filter having a light incident surface which is the surface opposite to the prism array and a boundary surface which is the surface opposite to the light incident surface and is the surface of the prism array, the angle which the boundary surface makes with the light incident surface being an inclination angle, the first layer having an inclination angle greater than a critical angle of the boundary surface, and a second layer laminated on the boundary surface, having a second refractive index and a light exit surface which is the surface opposite to the boundary surface, the second refractive index being smaller than the first refractive index and being equal to or greater than a third refractive index which is the refractive index of the atmosphere, the optical filter being arranged so that the light incident surface is on the spacer side, and light emitted from each pixel of the pixel group is incident on the light incident surface via the spacer.

Images