Optical element, imaging element, and imaging device

Abstract

The optical element comprises: a transparent layer, which is used to cover a plurality of pixels each including a photoelectric conversion element; and a plurality of structures, which are arranged on the transparent layer or in the transparent layer in the surface direction of the transparent layer, the plurality of structures are arranged to converge light of colors corresponding to the plurality of pixels in the incident light to the corresponding pixels, and the plurality of structures include structures having cross-sectional shapes of different types from each other when the transparent layer is viewed from above.

Description

Technical Field

[0001] The present invention relates to an optical element, an imaging element, and an imaging device. Background Art

[0002] Some image sensors include optical elements such as micro lenses and color filters. For example, Non-Patent Document 1 discloses a color filter.

[0003] Prior art literature

[0004] Non-patent literature

[0005] Non-patent document 1: Takanori Kudo, Yuki Nanjo, Yuko Nozaki, Kazuya Nagao, Hidemasa Yamaguchi, Wen-Bing Kang, Georg Pawlowski, PIGMENTED PHOTORESISTS FORCOLOR FILTERS, Journal of Photopolymer Science and Technology, 1996, Vol. 9, No. 1, pp. 109-119, 2006 / 08 / 04 / Summary of the invention

[0006] Problems to be solved by the invention

[0007] If two optical elements, a microlens and a color filter, are used, the manufacturing cost will be increased accordingly.

[0008] The object of the present invention is to reduce the manufacturing cost.

[0009] Means for solving problems

[0010] The optical element of the present invention is characterized in that it comprises: a transparent layer, which is used to cover multiple pixels that respectively include photoelectric conversion elements; and multiple structures, which are arranged on the transparent layer or in the transparent layer in the surface direction of the transparent layer, and the multiple structures are arranged to converge the colors of the incident light corresponding to the multiple pixels to the corresponding pixels.

[0011] The imaging element of the present invention comprises the above-mentioned optical element and the plurality of pixels covered by the transparent layer.

[0012] The imaging device of the present invention is characterized by comprising the imaging element described above and a signal processing unit that generates an image signal based on an electrical signal obtained from the imaging element.

[0013] Effects of the Invention

[0014] According to the present invention, the manufacturing cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a diagram showing an example of a schematic configuration of an image pickup element and an image pickup device using the optical element according to the embodiment.

[0016] Figure 2 This is a diagram showing an example of a schematic configuration of an image pickup element.

[0017] Figure 3 This is a diagram showing an example of a schematic configuration of an image pickup element.

[0018] Figure 4 This is a diagram showing an example of a schematic configuration of an image pickup element.

[0019] Figure 5 This is a diagram showing an example of a schematic configuration of an image pickup element.

[0020] Figure 6 It is a diagram schematically showing light focusing on corresponding pixels.

[0021] Figure 7 It is a diagram schematically showing light focusing on corresponding pixels.

[0022] Figure 8 It is a diagram schematically showing light focusing on corresponding pixels.

[0023] Fig. 9 : is a diagram showing an example of light intensity distribution on a pixel at each wavelength.

[0024] Fig.10 : is a diagram showing an example of light intensity distribution on a pixel at each wavelength.

[0025] Fig.11 : is a diagram showing an example of light intensity distribution on a pixel at each wavelength.

[0026] Fig.12 It is a diagram showing an example of a schematic structure of a structure.

[0027] Fig.13 It is a diagram showing an example of a schematic structure of a structure.

[0028] Fig.14 It is a diagram showing an example of a schematic structure of a structure.

[0029] Fig.15 It is a diagram showing an example of a schematic structure of a structure.

[0030] Fig.16 It is a diagram showing an example of a schematic structure of a structure.

[0031] Fig.17It is a diagram showing an example of a schematic structure of a structure.

[0032] Fig.18 It is a diagram showing an example of the combination of each wavelength and the optical phase delay amount.

[0033] Fig.19 It is a diagram showing an example of the combination of each wavelength and the optical phase delay amount.

[0034] Fig. 20 It is a diagram showing an example of lens design.

[0035] Fig.21 It is a diagram showing an example of lens design.

[0036] Fig. 22 It is a diagram showing an example of lens design.

[0037] Fig.23 It is a diagram showing an example of lens design.

[0038] Fig.24 It is a diagram showing an example of lens design.

[0039] Fig.25 It is a diagram showing an example of lens design.

[0040] Fig.26 It is a diagram showing an example of lens design.

[0041] Fig. 27 It is a diagram showing an example of lens design.

[0042] Fig.28 It is a diagram showing an example of lens design.

[0043] Fig.29 It is a diagram showing an example of lens design.

[0044] Fig.30 It is a diagram showing an example of lens design.

[0045] Fig.31 It is a diagram showing an example of lens design.

[0046] Fig.32 It is a diagram showing an example of lens design.

[0047] Fig.33 It is a diagram showing an example of lens design.

[0048] Fig.34 It is a diagram showing an example of lens design.

[0049] Fig.35 It is a diagram showing an example of lens design.

[0050] Fig.36 It is a diagram showing an example of lens design.

[0051] Fig.37 It is a diagram showing an example of lens design.

[0052] Fig.38 It is a diagram showing an example of lens design.

[0053] Fig.39 It is a diagram showing an example of lens design.

[0054] Fig.40 : is a diagram showing an example of the spectrum of light incident on a pixel.

[0055] Fig.41 : is a diagram showing an example of intensity distribution of light incident on a pixel.

[0056] Fig.42 : is a diagram showing an example of intensity distribution of light incident on a pixel.

[0057] Fig.43 : is a diagram showing an example of intensity distribution of light incident on a pixel.

[0058] Fig.44 : is a diagram showing an example of the spectrum of light incident on a pixel.

[0059] Fig.45 : is a diagram showing an example of intensity distribution of light incident on a pixel.

[0060] Fig.46 : is a diagram showing an example of intensity distribution of light incident on a pixel.

[0061] Fig.47 : is a diagram showing an example of intensity distribution of light incident on a pixel.

[0062] Fig.48 is a diagram showing an example of the incidence angle dependency.

[0063] Fig.49 is a diagram showing an example of the incidence angle dependency.

[0064] Fig.50 is a diagram showing an example of the incidence angle dependency.

[0065] Fig.51 is a diagram showing an example of the incidence angle dependency.

[0066] Fig.52 is a diagram showing an example of the incidence angle dependency.

[0067] Fig.53 is a diagram showing an example of the incidence angle dependency.

[0068] Fig.54 is a diagram showing an example of the incidence angle dependency.

[0069] Fig.55 is a diagram showing an example of the incidence angle dependency.

[0070] Fig.56 is a diagram showing an example of the incidence angle dependency.

[0071] Fig.57 is a diagram showing an example of the incidence angle dependency.

[0072] Fig.58 is a diagram showing an example of the incidence angle dependency.

[0073] Fig.59 is a diagram showing an example of the incidence angle dependency.

[0074] Fig.60 is a diagram showing an example of the incidence angle dependency.

[0075] Fig.61 is a diagram showing an example of the incidence angle dependency.

[0076] Fig.62 is a diagram showing an example of the incidence angle dependency.

[0077] Fig.63 is a diagram showing an example of the incidence angle dependency.

[0078] Fig.64 is a diagram showing an example of the incidence angle dependency.

[0079] Fig.65 is a diagram showing an example of the incidence angle dependency.

[0080] Fig.66 is a diagram showing an example of the incidence angle dependency.

[0081] Fig.67 A diagram showing an example of a schematic configuration of an image pickup element according to a modified example.

[0082] Fig.68 A diagram showing an example of a schematic configuration of an image pickup element according to a modified example.

[0083] Fig.69 It is a figure which shows the example of the cross-sectional shape of a structure.

[0084] Fig.70 A diagram showing an example of a schematic configuration of an image pickup element according to a modified example.

[0085] Fig.71 A diagram showing an example of a schematic configuration of an image pickup element according to a modified example.

[0086] Fig.72 : is a diagram showing an example of the spectrum of light incident on a pixel.

[0087] Fig.73 : is a diagram showing an example of the spectrum of light incident on a pixel.

[0088] Fig.74 is a diagram showing an example of the incidence angle dependency.

[0089] Fig.75 is a diagram showing an example of the incidence angle dependency.

[0090] Fig.76 is a diagram showing an example of the incidence angle dependency.

[0091] Fig.77 is a diagram showing an example of the incidence angle dependency.

[0092] Fig.78 is a diagram showing an example of the incidence angle dependency.

[0093] Fig.79 is a diagram showing an example of the incidence angle dependency.

[0094] Fig.80 is a diagram showing an example of the incidence angle dependency.

[0095] Fig.81 is a diagram showing an example of the incidence angle dependency.

[0096] Fig.82 is a diagram showing an example of the incidence angle dependency.

[0097] Fig.83 is a diagram showing an example of the incidence angle dependency.

[0098] Fig.84 is a diagram showing an example of the incidence angle dependency.

[0099] Fig.85 is a diagram showing an example of the incidence angle dependency.

[0100] Fig.86 is a diagram showing an example of the incidence angle dependency.

[0101] Fig.87 is a diagram showing an example of the incidence angle dependency.

[0102] Fig.88 is a diagram showing an example of the incidence angle dependency.

[0103] Fig.89 is a diagram showing an example of the incidence angle dependency.

[0104] Fig.90 is a diagram showing an example of the incidence angle dependency.

[0105] Fig.91 is a diagram showing an example of the incidence angle dependency. DETAILED DESCRIPTION

[0106] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The shapes, sizes, and positional relationships shown in the accompanying drawings are only schematic, and the present invention is not limited thereto. The same parts are marked with the same reference numerals, and repeated descriptions are omitted.

[0107] Figure 1 1 is a diagram showing an example of a schematic structure of an imaging element and an imaging device using an optical element of an embodiment. The imaging device 10 takes light from an object 1 (subject) shown as a hollow arrow as incident light and captures an image of the object 1. The incident light is incident on the imaging element 12 via a lens optical system 11. The signal processing unit 13 processes the electrical signal from the imaging element 12 to generate an image signal.

[0108] Figure 2 to Figure 5 : is a diagram showing an example of a schematic structure of an imaging element. In the figure, an XYZ coordinate system is shown. The XY plane direction corresponds to the surface direction of the pixel layer 3, the transparent layer 5, etc. described later. In the following, unless otherwise specified, "top view" means observation in the Z-axis direction (for example, the negative direction of the Z-axis). "Side view" means observation in the X-axis direction or the Y-axis direction (for example, the negative direction of the Y-axis).

[0109] The imaging element 12 includes a wiring layer 2, a pixel layer 3, and an optical element 4. The wiring layer 2, the pixel layer 3, and the optical element 4 are arranged in this order in the positive direction of the Z axis.

[0110] Figure 2 The layout of the pixel layer 3 when viewed from above is schematically shown. The pixel layer 3 is a pixel array including a plurality of pixels arranged in the XY plane direction. Each pixel is configured to include a photoelectric conversion element. An example of a photoelectric conversion element is a photodiode (PD: Photo Diode). Each pixel corresponds to any one of red (R), green (G) and blue (B). As an example of a wavelength band of red light, if the wavelength is λ0, then 600nm<λ0. An example of a wavelength band of green light is 500nm<λ0≤600nm. An example of a wavelength band of blue light is λ0≤500nm. In order to be able to distinguish each pixel by color, it is referred to as pixel R, pixel G1, pixel G2 and pixel B for illustration. The four pixels of pixel R, pixel G1, pixel G2 and pixel B adopt a Bayer arrangement to form one pixel unit (color pixel unit).

[0111] Figure 3 Shown along Figure 2 FIG. 1 is an example of a cross section of the imaging element 12 when viewed from the side along line III-III′. Figure 4 Shown along Figure 2 FIG. 1 is an example of a cross section of the imaging element 12 when viewed from the side along line IV-IV′. In the figure, arrows schematically indicate light incident on the imaging element 12. The incident light travels along the negative direction of the Z axis and reaches the pixel layer 3 via the optical element 4.

[0112] According to the principle described later, the optical element 4 focuses the red light of the incident light on the pixel R, focuses the green light on the pixels G1 and G2, and focuses the blue light on the pixel B. The charges generated in these pixels R, G1, G2, and B are converted into electric signals as the basis of pixel signals by transistors not shown, etc., and are output to the outside of the imaging element 12 via the wiring layer 2. Several wirings included in the wiring layer 2 are shown in the figure.

[0113] The optical element 4 is arranged in a manner covering the pixel layer 3. An example of the optical element 4 is a meta-surface. The meta-surface is composed of a plurality of microstructures (equivalent to the structure 6 described later) having a width less than the wavelength of light. The meta-surface can have a two-dimensional structure or a three-dimensional structure. Simply by changing the parameters of the microstructure, the phase and light intensity can be controlled according to the characteristics of the light (wavelength, polarization, angle of incidence). In the case of a three-dimensional structure, the design freedom is improved compared to a two-dimensional structure.

[0114] The optical element 4 has two functions, namely, a color separation function and a lens function. The color separation function is a function of separating incident light into lights of each color (each wavelength band) (spectroscopy function, light separation function). The lens function is a function of converging lights of each color to corresponding pixels. In this example, the incident light is separated into red light, green light, and blue light by the color separation function. By the lens function, red light is converged to pixel R, green light is converged to pixels G1 and G2, and blue light is converged to pixel B.

[0115] The optical element 4 includes a transparent layer 5 and a structure 6. The transparent layer 5 is provided on the pixel layer 3 in a manner covering the pixel layer 3. The transparent layer 5 may have a refractive index lower than that of the structure 6. The material of the transparent layer 5 is, for example, SiO2. The transparent layer 5 may also be a void, in which case the refractive index of the transparent layer 5 may be equal to the refractive index of air. The material of the transparent layer 5 may be a single material or a material in which multiple materials are layered.

[0116] A plurality of structures 6 are arranged on or in the transparent layer 5, for example, periodically (having a periodic structure) in the surface direction (XY plane direction) of the transparent layer 5. In this example, the structure 6 is arranged on the transparent layer 5 on the side opposite to the pixel layer 3 (Z-axis positive direction side) across the transparent layer 5. In order to make the design easier, the plurality of structures 6 can be arranged at equal intervals or at unequal intervals. Each structure 6 is a microstructure having a nanometer-scale size that is the same as or smaller than the wavelength of the incident light.

[0117] Figure 5 Schematically shows the Figure 2 An example of a cross section of a plurality of structures 6 corresponding to the portion surrounded by the dotted line V in . The plurality of structures 6 include a plurality of structures 61 (first structure), a plurality of structures 62 (second structure) and a plurality of structures 63 (third structure). When viewed from above, the plurality of structures 61 respectively have cross-sectional shapes of the same type (first type). The same type of cross-sectional shapes include cross-sectional shapes with different sizes (length, width, etc.). Similarly, the plurality of structures 62 respectively have cross-sectional shapes of the same type (second type). The plurality of structures 63 respectively have cross-sectional shapes of the same type (third type). The cross-sectional shape may be a four-fold rotationally symmetrical shape. Such a cross-sectional shape may be configured to include, for example, at least one of a square shape, a cross shape, and a circular shape.

[0118] The structure 61, the structure 62, and the structure 63 have different cross-sectional shapes from each other. Figure 5 In the example shown, the cross-sectional shape of the structure 61 is a square shape. The cross-sectional shape of the structure 62 is an X-shape. The X-shape is an example of a shape including a cross shape, and is a shape obtained by rotating the cross shape by 45° in the plane. The cross-sectional shape of the structure 63 is a hollow rhombus shape. The hollow rhombus shape is an example of a shape including a square shape, and is a shape obtained by rotating the hollow square shape by 45° in the plane.

[0119] In addition, if a shape such as an X-shape or a diamond shape is used after rotating 45 degrees in the plane, the optical coupling with the adjacent structure will be weakened, so the optical characteristics of each structure will not be affected by the adjacent structure and will be easily maintained. As a result, it is easy to reproduce the ideal phase delay amount distribution described later.

[0120] As described above, when the Bayer arrangement is adopted for the pixel R, the pixel G1, the pixel G2, and the pixel B, according to Figure 2 and Figure 5As can be seen from the comparison, the plurality of structures 6 arranged in the area opposite to the pixel G1 (or pixel G2) has an overall configuration structure obtained by rotating the overall configuration structure of the plurality of structures 6 arranged in the area opposite to the pixel G2 (or pixel G1) by 90°. This is because the configurations of the adjacent pixels R and pixels B are different in the pixels G1 and G2, respectively. By making the overall configuration structure of the structures 6 above the pixels G1 and G2 the same except for the rotation of 90°, efficient light focusing can be performed even in a complex color configuration such as the Bayer arrangement.

[0121] Figure 6 to Figure 8 Schematically shows the focusing of light to the corresponding pixel. Figure 6 As shown by the arrow in , the blue light converges to pixel B. In this example, not only the light above pixel B (in the positive direction of the Z axis) converges to pixel B, but also the light above the pixels around pixel B converges to pixel B. That is, the plurality of structures 6 ( Figure 3 to Figure 5 ) is configured so that light of a color corresponding to pixel B among light incident on the outside of the area opposite to pixel B is also focused on pixel B. Thus, compared with a case where only light incident on the area opposite to pixel B is focused on pixel B, the amount of received light can be increased.

[0122] like Figure 7 As shown by the arrows in , the green light converges to the pixel G1 and the pixel G2. In this example, not only the light above the pixel G1 and the pixel G2 converges to the pixel G1 and the pixel G2, but also the light above the pixels around the pixel G1 and the pixel G2 converges to the pixel G1 and the pixel G2. That is, the plurality of structures 6 are configured so that the light of the color opposite to the pixel G1 and the pixel G2 among the light incident on the outside of the area opposite to the pixel G1 and the pixel G2 is also converged to the pixel G1 and the pixel G2. Thus, compared with the case where only the light incident on the area opposite to the pixel G1 and the pixel G2 is converged to the pixel G1 and the pixel G2, the amount of received light can be increased.

[0123] like Figure 8 As shown by the arrow in , the red light is focused on the pixel R. In this example, not only the light above the pixel R is focused on the pixel R, but also the light above the pixels around the pixel R is focused on the pixel R. That is, the plurality of structures 6 are arranged so that the light of the color corresponding to the pixel R among the light incident on the outside of the region opposite to the pixel R is also focused on the pixel R. Thus, compared with the case where only the light incident on the region opposite to the pixel R is focused on the pixel R, the amount of received light can be increased.

[0124] Figures 9 to 11 An example of light intensity distribution for each wavelength (an example of calculation result) is shown. The area with high light intensity is shown brightly. Fig. 9As shown, blue light (in this example, wavelength λ0 = 430 nm) is concentrated in pixel B. Fig.10 As shown, green light (in this example, wavelength λ0 = 525 nm) is concentrated in pixel G1 and pixel G2. Fig.11 As shown, red light (in this example, wavelength λ0=635 nm) is concentrated in pixel R.

[0125] Figure 12 to Figure 17 is a diagram showing an example of a schematic structure of a structure. Fig.12 and Fig.13 , an example of the schematic structure of the structure 61 when viewed from the side and from above is shown. Fig.14 and Fig.15 , an example of the schematic structure of the structure 62 when viewed from the side and from above is shown. Fig.16 and Fig.17 , an example of a schematic structure of the structure 63 in a side view and a plan view is shown. Hereinafter, the structure 61, the structure 62, and the structure 63 may be simply referred to as "the structure 61, etc.".

[0126] The structure 61 and the like are columnar structures extending in the Z-axis direction and are formed on the base 6a. Examples of materials for the columnar structures are TiO2 (refractive index 2.40) or SiN (refractive index 2.05). The base 6a constitutes a transparent layer below the columnar structure. The base 61a is, for example, a part of a SiO2 substrate (refractive index 1.45). The side and top of the structure 61 and the like are air.

[0127] The width of the base 6a corresponding to each structure 61 is referred to as width W in the figure. The width W of the base 6a provides the arrangement period of the structure 61, etc. The width W can be set to W≤(λ min / n2) so that no diffracted light is generated on the transmission side. min It is the shortest wavelength in the wavelength band of the light receiving object, for example, 410 nm. n2 is the refractive index of the base 6a, and when the base 6a is SiO2, n2 = 1.45. The width W (arrangement period of the structure 61, etc.) is 280 nm.

[0128] The height (length in the Z-axis direction) of the structure 61 etc. when viewed from the side is referred to as height H in the figure. The height H of the structure 61 etc. may be the same. The height H may be set to H ≥ λ r / (n1-n0), so that the structure 61 and the like can give an optical phase delay (phase value) of 2π or more to the incident light, that is, the light traveling along the Z-axis direction. rIt is the desired central wavelength in the wavelength band on the longest wavelength side of the wavelength band of the light to be color separated. n1 is the refractive index of the structure 61, etc. When the structure 61, etc. is TiO2, n1=2.40, and the height H is, for example, 1250nm. When the structure 61, etc. is SiN, n1=2.05, and the height H is, for example, 1600nm.

[0129] By designing the cross-sectional shape (including the size design) of the structure 61, various combinations that can give different optical phase delays to light of each color (light of each wavelength) can be realized. By diversifying the cross-sectional shape, the combinations increase, and the degree of design freedom is further improved.

[0130] Fig.18 and Fig.19 This is a diagram showing examples of combinations of wavelengths and optical phase delay amounts. As an example of blue light, the optical phase delay amount relative to light with a wavelength of 430nm (Phase (Phase) @λ = 430nm (rad / π)) is shown. As an example of green light, the optical phase delay amount relative to light with a wavelength of 520nm (Phase @λ = 520nm (rad / π)) is shown. As an example of red light, the optical phase delay amount relative to light with a wavelength of 635nm (Phase @λ = 635nm (rad / π)) is shown.

[0131] The square plots indicate the light phase delay when the cross-sectional dimensions of the structure 61 having a square cross-sectional shape are set to various dimensions. The X-shaped plots indicate the light phase delay when the cross-sectional dimensions of the structure 62 having an X-shaped cross-sectional shape are set to various dimensions. The diamond plots indicate the light phase delay when the cross-sectional dimensions of the structure 63 having a hollow diamond cross-sectional shape are set to various dimensions. The height H is constant. The black circle plots indicate the ideal light phase delay in the lens design described later.

[0132] Fig.18 The optical phase delay amount when the structure 61 and the like are TiO 2 is shown. Fig.19 The optical phase delay when the structure 61 and the like are SiN is shown. It can be understood that by designing the cross-sectional shape of the structure 61 and the like, various combinations of light of each color (light of each wavelength) and the optical phase delay can be achieved. That is, even if only columnar structures having the same height H are used, optical phase delay characteristics (phase characteristics) having a variety of wavelength dispersions can be achieved. This is because the wavelength dispersion characteristics of the generated optical waveguide mode / optical resonance mode and the optical phase delay caused by the optical waveguide mode / optical resonance mode can be changed according to the cross-sectional shape.

[0133] Based on the above principle, by designing the cross-sectional shape and configuration of the structure 61 and the like arranged in the surface direction of the transparent layer 5, it is possible to realize a lens function having different focusing points for each wavelength. In addition, the lens design is not limited to the case where the wavelength is 3, and the lens design can also be performed when the wavelength is 2 or more than 4.

[0134] Reference Figure 20 to Figure 39 An example of lens design is described. In lens design, the cross-sectional shape and configuration of the structure 61, etc. are designed to achieve an ideal light phase delay distribution (phase distribution). In the example described below, the cross-sectional shape and configuration of the structure 61, etc. are designed according to the ideal light phase delay distribution of each center wavelength of the respective wavelength bands of red light, green light, and blue light. The pixel size is 1.68μm×1.68μm. The focal length is 4.2μm. The center wavelength corresponding to blue light is 430nm. The center wavelength corresponding to green light is 520nm. The center wavelength corresponding to red light is 635m.

[0135] When the ideal optical phase delay distribution is set to hour, It is expressed by the following formula.

[0136] [Mathematical formula 1]

[0137]

[0138] In the above formula (1), λ d is the center wavelength (design wavelength). f , Y f and Z f is the focusing position. n2 is the refractive index of the base 6a. C is an arbitrary constant.

[0139] The ideal optical phase retardation distribution is a phase distribution that provides the following light-converging positions to each of the pixel B, the pixel G1, the pixel G2, and the pixel R. The center positions of the four pixels (pixel units) correspond to x=0 and y=0.

[0140] Pixel B:X f = +0.84 μm, y f =-0.84μm, Z f =4.2μm

[0141] Pixel G1:X f = +0.84 μm, y f = +0.84 μm, Z f =4.2μm

[0142] Pixel G2:X f =-0.84μm, yf =-0.84μm, Z f =4.2μm

[0143] Pixel R:X f =-0.84μm, y f = +0.84 μm, Z f =4.2μm

[0144] It is transformed in a manner that converges to the range of 0 to 2π. For example, -0.5π and 2.5π are transformed into 1.5π and 0.5π, respectively. The boundary area of ​​the optical phase delay distribution is set so that the optical phase delay distribution at each center wavelength is symmetrical left and right and up and down with the focusing position as the center (together with the adjacent lens). The constant C can be optimized so that the error (difference from the ideal value) of the optical phase delay distribution at each wavelength is minimized. According to the optical phase delay at each wavelength, the structure that is most suitable for the optical phase delay distribution at each center wavelength (the structure with the smallest error) is configured at the corresponding position.

[0145] Figure 20 to Figure 29 An example of lens design when the structure 61 etc. is TiO2 is shown. Fig. 20 As shown, a plurality of structures 61 and the like are arranged. The center position of the structure 61 and the like shown in the figure corresponds to x=0 and y=0.

[0146] Fig.21 The ideal optical phase retardation distribution (phase (rad / π)) when the central wavelength is 430 nm (blue light) is shown. Fig. 22 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=0.98 μm is shown. Fig.23 The example of the optical phase retardation distribution in the X-axis direction at y = -0.98 μm is shown. The dotted line (Ideal: ideal) represents the ideal optical phase retardation distribution, and the plot (Designed: designed) represents the distribution of the optical phase retardation by the above Fig. 20 The optical phase delay distribution obtained by arranging a plurality of structures 61 shown in FIG.

[0147] Fig.24 The ideal optical phase delay distribution when the central wavelength is 520 nm (green light) is shown. Fig.25 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=0.98 μm is shown. Fig.26 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=-0.98 μm is shown.

[0148] Fig. 27 The ideal optical phase delay distribution when the central wavelength is 635 nm (red light) is shown. Fig.28 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=0.98 μm is shown. Fig.29 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=-0.98 μm is shown.

[0149] It can be understood that in any case where the central wavelength is 430 nm, 520 nm, and 635 nm (blue light, green light, and red light), a nearly ideal optical phase delay distribution can be obtained.

[0150] Figure 30 to Figure 39 FIG. 6 shows an example of lens design when the structure 61 and the like are made of SiN. Fig.30 As shown, a plurality of structures 61 and the like are arranged.

[0151] Fig.31 The ideal optical phase delay distribution when the central wavelength is 430nm (blue light) is shown. Fig.33 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=-0.98 μm is shown.

[0152] Fig.34 The ideal optical phase delay distribution when the central wavelength is 520 nm (green light) is shown. Fig.35 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=0.98 μm is shown. Fig.36 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=-0.98 μm is shown.

[0153] Fig.37 The ideal optical phase delay distribution when the central wavelength is 635 nm (red light) is shown. Fig.38 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=0.98 μm is shown. Fig.39 An example of the distribution of the optical phase retardation amount in the X-axis direction at y=-0.98 μm is shown.

[0154] It can be understood that in any case where the central wavelength is 430 nm, 520 nm, and 635 nm (blue light, green light, and red light), a nearly ideal optical phase delay distribution can be obtained.

[0155] Reference Figures 40 to 47 The spectrum and intensity distribution of light incident on a pixel will be described.

[0156] Fig.40An example of the spectrum of light incident on each pixel when the structure 61, etc. is TiO2 is shown. The spectrum is the spectrum when an unpolarized plane light wave is incident perpendicularly to the substrate (XY plane). The distance from the lower end of the structure 61, etc. (lens structure end) to the pixel layer 3 is 4.2μm (lens focal length). The horizontal axis of the graph represents the wavelength (Wavelength (nm)). The vertical axis represents the light receiving efficiency (Detected power). The light receiving efficiency is (light intensity on the pixel) / (incident light intensity incident on the structure 61, etc.). For example, when half of the light incident on the structure 61, etc. is incident on the pixel, the light receiving efficiency is 0.5.

[0157] Light is focused on each pixel in such a way that each pixel has a peak in the wavelength band of the corresponding color light. The spectrum of light incident on pixel R is represented by curve R. The spectrum of light incident on pixel G1 and pixel G2 is represented by curve G1 and curve G2. The spectrum of light incident on pixel B is represented by curve B. As a comparative example, the upper limit value of the light receiving efficiency of 0.2 in the case where a general filter (color filter) is used instead of the optical element 4 of the embodiment is represented as the filter limit (Filter limit (T max =80%)). The upper limit value of the light receiving efficiency of 0.2 is a value obtained by dividing the filter having a maximum transmittance of 80% at each wavelength into four pixels, namely, pixel R, pixel G1, pixel G2, and pixel B (0.8 / 4=0.2).

[0158] It can be seen that the pixel R, the pixel G1, the pixel G2, and the pixel B all have a peak value greater than the upper limit value 0.2 of the comparative example, and the amount of light received in the pixel is greater than that of the comparative example. For example, at a wavelength of 430nm represented by the mark MA, the light receiving efficiency of the pixel B greatly exceeds the upper limit value 0.2 of the comparative example. At a wavelength of 525nm represented by the mark MB, the light receiving efficiency of the pixel G1 and the pixel G2 also greatly exceeds the upper limit value 0.2 of the comparative example. At a wavelength of 635nm represented by the mark MC, the light receiving efficiency of the pixel R also greatly exceeds the upper limit value 0.2 of the comparative example.

[0159] The total transmittance, i.e., (the sum of the light intensities on all pixels) / (the incident light intensity incident on the structure 61, etc.), is averaged within the wavelength range of 400nm to 700nm, and the value is 93.2%, which greatly exceeds the upper limit of 33% when using a general filter. This shows that the light receiving efficiency of the pixel can be improved.

[0160] Fig.41 Shows that there is Fig.40 The intensity distribution of light (blue light) with a wavelength marked MA in FIG. It can be seen that the distribution is concentrated in pixel B. Fig.42 Shows that there is Fig.40The intensity distribution of the light (green light) with the wavelength of the marker MB in FIG. It can be seen that the distribution is concentrated in the pixel G1 and the pixel G2. Fig.43 Shows that there is Fig.40 The intensity distribution of light (red light) with the wavelength marked MC in FIG.

[0161] Fig.44 An example of the spectrum of light incident on each pixel when the structure 61, etc. is SiN is shown. As in the case where the structure 61, etc. is SiO2, the pixels R, G1, G2, and B all have peak values ​​greater than the upper limit of 0.2 of the comparative example, and the amount of light received in the pixel is greater than that of the comparative example. The total transmittance is 97.1%, which greatly exceeds the upper limit of 33% when a general filter is used.

[0162] Fig.45 Shows that there is Fig.44 The intensity distribution of light (blue light) with a wavelength marked MA in FIG. It can be seen that the distribution is concentrated in pixel B. Fig.46 Shows that there is Fig.44 The intensity distribution of the light (green light) with the wavelength of the mark MB in FIG. 1 is shown in FIG. 1 . In the case of SiN, the wavelength indicated by the mark MB is 520 nm. It can be seen that the distribution is concentrated in the pixel G1 and the pixel G2. Fig.47 Shows that there is Fig.44 The intensity distribution of light (red light) with the wavelength marked MC in FIG.

[0163] Figures 48 to 66 is a diagram showing an example of the incidence angle dependency. Figures 48 to 58 An example of the incident angle dependency when the structure 61 and the like are TiO 2 is shown.

[0164] As mentioned above, Fig.48 As shown in FIG. 1 , pixels R, G1, G2, and B are configured. Fig.49 As shown in FIG. 1 , when the angle (Angle) on the XZ plane with the Z-axis direction as 0° is taken as the incident angle, the incident angle dependence is as follows: Figure 50 to Figure 53 As shown. Fig.50 In FIG. 1 , the light receiving efficiency of the pixel R is shown by a spectrum for each wavelength (Wavelength (μm)) and each incident angle (Incident angle (degree), that is, for each incident angle. Fig.51 In FIG. 1 , the light receiving efficiency of the pixel G1 is shown by a spectrum for each incident angle. Fig.52 In FIG. 1 , the light receiving efficiency of pixel G2 is shown by a spectrum for each incident angle. Fig.53, the light receiving efficiency of pixel B is shown by the spectrum for each incident angle. In any case of pixel R, pixel G1, pixel G2, and pixel B, the spectrum does not change significantly within the range of the incident angle of about ±12°.

[0165] like Fig.54 As shown in FIG. 1 , when the angle (Angle) on the YZ plane with the Z-axis direction set to 0° is taken as the incident angle, the incident angle dependence is as follows: Figure 55 to Figure 58 As shown. Fig.55 In FIG. 1 , the light receiving efficiency of the pixel R is shown by a spectrum for each incident angle. Fig.56 In FIG. 1 , the light receiving efficiency of the pixel G1 is shown by a spectrum for each incident angle. Fig.57 In FIG. 1 , the light receiving efficiency of pixel G2 is shown by a spectrum for each incident angle. Fig.58 , the light receiving efficiency of pixel B is shown by the spectrum for each incident angle. In any case of pixel R, pixel G1, pixel G2, and pixel B, the spectrum does not change significantly within the range of the incident angle of about ±12°.

[0166] Figures 59 to 66 An example of the incident angle dependency when the structure 61 and the like are SiN is shown.

[0167] As previously explained Fig.49 The incident angle dependence on the XZ plane is shown as Figures 59 to 62 shown. Fig.59 The angle dependency of incidence to the pixel R is shown. Fig.60 The angle dependency of incidence to pixel G1 is shown. Fig.61 The angle dependency of incidence to pixel G2 is shown. Fig.62 The incident angle dependency on the pixel B is shown. In the case of any pixel, the spectrum does not change significantly within the incident angle range of about ±12°.

[0168] As previously explained Fig.54 The incident angle dependence on the YZ plane is shown as Figure 63 to Figure 66 shown. Fig.63 The angle dependency of incidence to the pixel R is shown. Fig.64 The angle dependency of incidence to pixel G1 is shown. Fig.65 The angle dependency of incidence to pixel G2 is shown. Fig.66 The diagram shows the incident angle dependency on the pixel B. In the case of any pixel, the spectrum does not change significantly within the incident angle range of about ±12°.

[0169] As described above, it has been confirmed that the incident angle has a tolerance of at least ±12°. This means that, for example, even when using a camera lens with an NA (numerical aperture) of ~0.21 for video recording, it is difficult to produce color errors. Considering that the NA of a general camera lens (telephoto) of a camera such as a smartphone is about 0.2, the optical element 4 of the embodiment may also be used in a smartphone camera, etc. In addition, the tolerance to the incident angle mainly depends on the focal length, so if a lens with a shorter focal length is designed, the angle is allowed to be further expanded.

[0170] As described above, according to the optical element 4, two functions of the lens function are realized. For example, the imaging element of the prior art does not have the optical element 4, but has a filter (for example, a color filter). That is, the filter corresponding to the color of each pixel is set in a manner covering the pixel. In this case, since the light of wavelengths outside the transmission band is absorbed by the filter, the amount of light passing through the filter only remains about 1 / 3 of the amount of light incident on the filter, and the light receiving efficiency is reduced. In contrast, according to the imaging element 12 of the embodiment, as described above, the amount of light is maintained more than that (for example, more than 90%), so the light receiving efficiency is greatly improved.

[0171] In addition, in the prior art, in order to increase the amount of received light (increase sensitivity) by increasing the aperture ratio, reducing the light incident angle dependence, etc., there is also a technology in which a microlens is provided (integrated) on the side opposite to the pixel across the filter. In this case, since it becomes a two-layer structure with at least a filter and a microlens, the structure becomes complicated and the manufacturing cost will also increase. According to the optical element 4 of the embodiment, the color separation function and the lens function can be realized only by the optical element 4, so the structure can be simplified and the manufacturing cost can be reduced. In addition, since a plurality of structures 6 can be arranged without gaps in the plane (in the XY plane), the aperture ratio is increased compared with the microlens.

[0172] Return again Figure 1 , the signal processing unit 13 of the imaging device 10 is described. The signal processing unit 13 generates a pixel signal based on the electrical signal obtained from the imaging element 12. In order to obtain the electrical signal, the signal processing unit 13 also controls the imaging element 12. The control of the imaging element 12 includes exposure of pixels of the imaging element 12, conversion of charges accumulated in the pixel layer 3 into electrical signals, and reading of electrical signals.

[0173] An embodiment of the present invention has been described above, but the optical element, the imaging element, and the imaging device of the embodiment can be modified in various ways without departing from the gist of the embodiment. Several modified examples will be described below.

[0174] In the above embodiment, an example is described in which the plurality of structures 6 are provided on the transparent layer 5 on the side opposite to the pixel layer 3 via the transparent layer 5. However, the structure of the transparent layer 5 and the plurality of structures 6 is not limited thereto.

[0175] Fig.67 and Fig.68 FIG. 2 is a diagram showing an example of a schematic structure of an image pickup element according to a modified example. Fig.67 In the illustrated imaging element 12A, in the optical element 4A, a plurality of structures 6 are provided in the transparent layer 5. The structures 6 are embedded in the transparent layer 5 on the pixel layer 3 (on the PD). Fig.68 In the illustrated imaging element 12B, in the optical element 4B, the transparent layer 5 includes a transparent substrate 5a and an air layer 5b. The plurality of structures 6 are provided on (supported by) the transparent substrate 5a so as to extend from the transparent substrate 5a toward the pixel layer 3 (Z-axis negative direction).

[0176] The cross-sectional shape of the structure 6 is not limited to the above-described Figure 5 The shapes shown. Fig.69 2 is a diagram showing an example of a cross-sectional shape of a structure. The structure 6 can have various cross-sectional shapes shown in the examples. The shapes shown in the examples are, for example, four-fold rotationally symmetrical shapes obtained by variously combining a square shape, a cross shape, and a circular shape.

[0177] The imaging element may include an optical filter. Fig.70 and Fig.71 12C is a diagram showing an example of a schematic structure of an image sensor according to such a modification. The image sensor 12C shown in the example includes a filter layer 7 provided between the pixel layer 3 and the optical element 4 . Fig.70 Shows the Figure 2 An example of a cross section of the imaging element 12C when viewed from the side along the line III-III′ when the imaging element 12 in FIG. 1 is replaced by the imaging element 12C. Fig.71 Shows the Figure 2 An example of a cross section of the imaging element 12C when viewed from the side along the line IV-IV′ when the imaging element 12 in FIG. 1 is replaced by the imaging element 12C.

[0178] The filter layer 7 includes a filter 7R, a filter 7G1, a filter 7G2, and a filter 7B. The filter 7R is arranged to cover the pixel R so that red light passes through. The filter 7G1 is arranged to cover the pixel G1 so that green light passes through. The filter 7G2 is arranged to cover the pixel G2 so that green light passes through. The filter 7B is arranged to cover the pixel B so that blue light passes through. Examples of materials of the filter 7R, the filter 7G1, the filter 7G2, and the filter 7B are organic materials such as resins.

[0179] The light that has been color-separated by the optical element 4 further passes through the filter layer 7 and reaches the pixel layer 3. By performing color separation by both the optical element 4 and the filter layer 7, the crosstalk of the spectrum is suppressed (most of the unnecessary other color components are removed) and the color reproducibility is improved compared to the case where only one side performs color separation. In addition, the incident light passes through the filter layer 7 after being separated by the optical element 4, so the amount of light is not greatly reduced. Therefore, compared with the case where there is no optical element 4 and only the filter layer 7 is provided, the light receiving efficiency of the pixel is improved.

[0180] Fig.72 and Fig.73 : is a diagram showing an example of the spectrum of light incident on a pixel.

[0181] Fig.72 An example of a spectrum when the structure 61, etc. is TiO2 is shown. The light receiving efficiency of pixel R is represented by the curve metalens×R filter (R). The light receiving efficiency of pixels G1 and G2 is represented by the curve metalens×G filter (G1 or G2). The light receiving efficiency of pixel B is represented by the curve metalens×B filter (B). As a comparative example, the light receiving efficiency of pixel R in the case where there is no optical element 4 and only a general filter is provided is represented by the curve R filter (R). The light receiving efficiency of pixel G is represented by the curve G filter (G1 or G2). The light receiving efficiency of pixel B is represented by the curve B filter (B).

[0182] The peak values ​​of the spectra of pixel R, pixel G1, pixel G2, and pixel B are also about 1.2 to 2.0 times that of the comparative example, and a greater light receiving efficiency can be obtained than that of the comparative example. The total transmittance is also 43.3%, which greatly exceeds the 34.7% (about 1.25 times) of the comparative example. In addition, the spectrum of light incident on each pixel is also sharper than that of the comparative example, and it can also be seen that other unnecessary color components can be reduced accordingly. As a result, color reproducibility is improved.

[0183] Fig.73An example of a spectrum when the structure 61 and the like are SiN is shown. The peak values ​​of the spectra of pixel R, pixel G1, pixel G2, and pixel B are also about 1.2 to 2.0 times that of the comparative example, and a greater light receiving efficiency than the comparative example can be obtained. The total transmittance is also 45%, which greatly exceeds the 34.7% (about 1.30 times) of the comparative example. Moreover, compared with the comparative example, the spectrum of light incident on each pixel is also sharper than the spectrum of the comparative example, and it can also be seen that other unnecessary color components can be reduced accordingly. As a result, color reproducibility is improved.

[0184] Reference Figures 74 to 91 The incident angle dependency will be described. Figures 74 to 83 An example of the incident angle dependency when the structure 6 is TiO 2 is shown.

[0185] Fig.74 The incident angle dependence on the XZ plane is shown as Figure 75 to Figure 78 shown. Fig.75 The angle dependency of incidence to the pixel R is shown. Fig.76 The angle dependency of incidence to pixel G1 is shown. Fig.77 The angle dependency of incidence to pixel G2 is shown. Fig.78 The diagram shows the incident angle dependency on the pixel B. In the case of any pixel, the spectrum does not change significantly within the incident angle range of about ±12°.

[0186] Fig.79 The incident angle dependence on the YZ plane is shown as Figure 80 to Figure 83 shown. Fig.80 The angle dependency of incidence to the pixel R is shown. Fig.81 The angle dependency of incidence to pixel G1 is shown. Fig.82 The angle dependency of incidence to pixel G2 is shown. Fig.83 The diagram shows the incident angle dependency on the pixel B. In the case of any pixel, the spectrum does not change significantly within the incident angle range of about ±12°.

[0187] Figures 84 to 91 An example of the incident angle dependency when the structure 61 and the like are SiN is shown.

[0188] As previously explained Fig.74 The incident angle dependence on the XZ plane is shown as Figure 84 to Figure 87 shown. Fig.84 The angle dependency of incidence to the pixel R is shown. Fig.85 The angle dependency of incidence to pixel G1 is shown. Fig.86 The angle dependency of incidence to pixel G2 is shown. Fig.87The diagram shows the incident angle dependency on the pixel B. In the case of any pixel, the spectrum does not change significantly within the incident angle range of about ±12°.

[0189] As previously explained Fig.79 The incident angle dependence on the YZ plane is shown as Figures 88 to 91 shown. Fig.88 The angle dependency of incidence to the pixel R is shown. Fig.89 The angle dependency of incidence to pixel G1 is shown. Fig.90 The angle dependency of incidence to pixel G2 is shown. Fig.91 The diagram shows the incident angle dependency on the pixel B. In the case of any pixel, the spectrum does not change significantly within the incident angle range of about ±12°.

[0190] As described above, according to the imaging element 12C further including the filter layer 7 , it is possible to improve the light receiving efficiency and further improve the color reproducibility.

[0191] In the above embodiment, TiO2 and SiN are used as examples of the material of the structure 6. However, the material of the structure 6 is not limited thereto. For example, for light with a wavelength of 380nm to 1000nm (visible light to near-infrared light), in addition to SiN, SiC, TiO2, GaN, etc. can also be used as the material of the structure 6. These materials are suitable because of their high refractive index and low absorption loss. When used for light with a wavelength of 800 to 1000nm (near-infrared light), Si, SiC, SiN, TiO2, GaAs, GaN, etc. can be used as the material of the structure 6. These materials are suitable because of their low loss. For light in the long-wave near-infrared region (1.3μm, 1.55μm, etc. as communication wavelengths), in addition to the above-mentioned materials, InP, etc. can also be used as the material of the structure 6.

[0192] When the structure 6 is formed by laminating, coating or the like, examples of the material include polyimide such as fluorinated polyimide, BCB (benzocyclobutene), photocurable resin, UV epoxy resin, acrylic resin such as PMMA, polymers such as resist bulk, and the like.

[0193] In the above embodiment, an example in which SiO2 and an air layer are assumed as the material of the transparent layer 5 is shown, but it is not limited to this. It also includes general glass materials, etc., as long as it has a refractive index lower than the refractive index of the material of the structure 6 and has a low loss relative to the wavelength of the incident light. The transparent layer 5 only needs to have a sufficiently low loss for the wavelength of the light that should reach the corresponding pixel, so it can be the same material as the color filter, for example, it can also be an organic material such as resin. In this case, the transparent layer 5 is not only the same material as the color filter, but also has the same structure as the color filter, and can also be designed to have an absorption characteristic corresponding to the wavelength of the light that should be guided to the corresponding pixel.

[0194] In the above embodiment, the three primary colors of RGB are used as an example of the colors corresponding to the pixels, but the pixels may also correspond to light of wavelengths other than the three primary colors (for example, infrared light, ultraviolet light, etc.).

[0195] In the above embodiment, an example is described in which three structures having different cross-sectional shapes, namely, the structure 61, the structure 62, and the structure 63, are used. However, two structures (for example, only the structure 61 and the structure 62) or four or more structures may be used.

[0196] As mentioned above, although this invention was demonstrated based on the specific embodiment, this invention is not limited to the said embodiment, Of course, various changes can be made within the range which does not deviate from the summary.

[0197] The above-described technology is determined, for example, by the following method. Figure 1 to Figure 5 , Fig.67 and Fig.68 As described in the examples above, the optical element 4 includes: a transparent layer 5 for covering a plurality of pixels (such as pixel R) each including a photoelectric conversion element; and a plurality of structures 6 arranged on or in the transparent layer 5 in the surface direction (XY plane direction) of the transparent layer 5. The plurality of structures 6 are arranged to focus the colors (such as red, green, and blue) corresponding to the plurality of pixels in the incident light to the corresponding pixels. The plurality of structures 6 include structures (such as structures 61, 62, and 63) having cross-sectional shapes (such as square shapes, X-shaped shapes, and hollow rhombus shapes) of different types from each other when the transparent layer 5 is viewed from above (when viewed in the Z-axis direction).

[0198] The optical element 4 has both color separation and lens functions (light-gathering functions). Therefore, compared with, for example, providing a filter (e.g., a color filter) corresponding to each pixel and further providing a microlens, the light receiving efficiency of the pixel can be greatly improved, and the light receiving sensitivity can be improved. Since the structure is simplified, the manufacturing cost can also be reduced. Since a plurality of structures 6 can be arranged without gaps in the plane, the aperture ratio is also increased compared with the microlens.

[0199] As reference Figure 12 to Figure 17 As described in the examples above, each of the plurality of structures 6 may be a columnar structure having a refractive index higher than that of the transparent layer 5 and providing an optical phase delay amount corresponding to the cross-sectional shape to the incident light. Figure 20 to Figure 39 As described in the above, a plurality of structures 6 may be arranged according to the distribution of the optical phase delay for realizing the above-mentioned focusing. For example, by arranging such a plurality of structures 6, both the color separation function and the lens function can be realized.

[0200] As reference Figure 5 and Fig.69 As described in the above, the cross-sectional shape of each of the plurality of structures 6 may be a four-fold rotationally symmetric shape. This can prevent the occurrence of polarization dependence.

[0201] As reference Figure 6 to Figure 8 As described in the above, the plurality of structures 6 may be arranged so that the light of the color corresponding to the one pixel among the light incident on the outside of the area opposite to the one pixel is also focused on the one pixel. Thus, the amount of received light can be increased compared to the case where only the light incident on the area opposite to the one pixel is focused on the pixel.

[0202] As reference Figure 2 and Figure 5 As described in , etc., a plurality of pixels include a pixel unit, the pixel unit is composed of one pixel R corresponding to red, two pixels G1 and pixel G2 corresponding to green, and one pixel B corresponding to blue in a Bayer arrangement, and a plurality of structural bodies 6 arranged in a region opposite to one pixel corresponding to green in the pixel unit (e.g., pixel G1) may have an overall arrangement structure obtained by rotating the overall arrangement structure of a plurality of structural bodies arranged in a region opposite to another pixel corresponding to green (e.g., pixel G2) by 90°. By making the overall arrangement structure of the plurality of structural bodies 6 the same except for the rotation by 90° in this way, efficient light focusing can be performed even in a complex color arrangement such as the Bayer arrangement.

[0203] Reference Figure 1 to Figure 5The imaging element 12 described in the above is also one embodiment of the present disclosure. The imaging element 12 includes an optical element 4 and a plurality of pixels (such as pixels R) covered by a transparent layer 5. As described above, the manufacturing cost can be reduced. The light receiving sensitivity can also be improved, and the aperture ratio can be increased.

[0204] As reference Fig.70 and Fig.71 As described in the above, the image sensor 12C may include a filter layer 7 provided between a plurality of pixels (pixels R, etc.) and the transparent layer 5. This can improve light receiving efficiency and further improve color reproducibility.

[0205] Reference Figure 1 The imaging device 10 described in the above is also one embodiment of the present disclosure. The imaging device 10 includes the imaging element 12 and a signal processing unit 13 that generates an image signal based on an electrical signal obtained from the imaging element 12 and a pixel signal. As described above, the manufacturing cost can be reduced. The light receiving sensitivity can also be improved, and the aperture ratio can be increased.

[0206] Description of Reference Numerals

[0207] 3 Pixel Layers

[0208] 4 Optical components

[0209] 5 Transparent Layer

[0210] 6 Structure

[0211] 7 Filter layer

[0212] 10 Camera device

[0213] 11 Lens Optical System

[0214] 12 Camera Components

[0215] 61 Structure

[0216] 62 Structure

[0217] 63 Structure

[0218] R Pixel

[0219] G1 Pixel

[0220] G2 Pixel

[0221] B Pixel

Claims

1. An optical element, characterized in that: have: a transparent layer for covering a plurality of pixels each including a photoelectric conversion element; and a plurality of structures arranged on or in the transparent layer in the surface direction of the transparent layer, The plurality of structures are configured to focus light of colors corresponding to the plurality of pixels, respectively, among incident light, to the corresponding pixels. The cross-sectional shapes of the plurality of structures when the transparent layer is viewed from above are designed and arranged so that light of a color corresponding to one pixel, among light incident outside a region facing one pixel, is also focused on the one pixel.

2. An optical element, characterized in that: have: a transparent layer for covering a plurality of pixels each including a photoelectric conversion element; and a plurality of structures arranged on or in the transparent layer in the surface direction of the transparent layer, The plurality of structures are configured to focus light of colors corresponding to the plurality of pixels, respectively, among incident light, to the corresponding pixels. The plurality of pixels include a pixel unit, the pixel unit being composed of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue in a Bayer arrangement, Among the plurality of structures, the plurality of structures arranged in a region facing one pixel corresponding to green in the pixel unit has an overall arrangement structure obtained by rotating the overall arrangement structure of the plurality of structures arranged in a region facing another pixel corresponding to green by 90°.

3. The optical element according to claim 1 or 2, characterized in that: Each of the plurality of structures is a columnar structure having a refractive index higher than that of the transparent layer and providing incident light with an optical phase retardation amount corresponding to a cross-sectional shape of the transparent layer when viewed from above. The plurality of structures are arranged according to a distribution of light phase delay amounts for achieving the convergence, The cross-sectional shape of each of the plurality of structures is a four-fold rotationally symmetric shape.

4. The optical element according to claim 1 or 2, characterized in that: The plurality of pixels include a pixel unit, the pixel unit being composed of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue in a Bayer arrangement, Among the plurality of structures, the plurality of structures arranged in the region facing the pixel corresponding to red in the pixel unit has a four-fold rotationally symmetrical overall arrangement structure, Among the plurality of structures, the plurality of structures arranged in a region facing a pixel corresponding to blue in the pixel unit has an overall arrangement structure with four-fold rotational symmetry.

5. An imaging element, characterized in that: The imaging element comprises: The optical element according to claim 1 or 2; and The plurality of pixels are covered by the transparent layer.

6. The imaging element according to claim 5, wherein: The imaging element includes a filter layer provided between the plurality of pixels and the transparent layer.

7. A camera device, characterized in that: The camera device comprises: The imaging element according to claim 5; and A signal processing unit generates an image signal based on the electric signal obtained from the imaging element.

Images