Image sensor and imaging device

Abstract

Reduce manufacturing costs. [Solution] The image sensor comprises a plurality of pixels, each containing a photoelectric conversion element; a transparent layer covering the plurality of pixels; and a plurality of structures arranged on or within the transparent layer in the plane direction of the transparent layer. The plurality of structures include structures having different types of cross-sectional shapes when the transparent layer is viewed from above. The plurality of structures concentrate light of the color corresponding to that pixel from the light incident outside the region facing that pixel onto that pixel.

Description

[Technical Field]

[0001] The present invention relates to an image sensor and an imaging device. [Background technology]

[0002] Some image sensors are equipped with optical elements such as microlenses and color filters. A color filter is shown, for example, in Non-Patent Document 1. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Takanori Kudo, Yuki Nanjo, Yuko Nozaki, Kazuya Nagao, Hidemasa Yamaguchi, Wen-Bing Kang, Georg Pawlowski, PIGMENTED PHOTORESISTS FOR COLOR FILTERS, Journal of Photopolymer Science and Technology, 1996, Volume 9, Issue 1, p.109-119, 2006 / 08 / 04 [Overview of the project] [Problems that the invention aims to solve]

[0004] Using two optical elements, a microlens and a color filter, increases manufacturing costs.

[0005] The present invention aims to reduce manufacturing costs. [Means for solving the problem]

[0006] In one aspect, the image sensor comprises a plurality of pixels, each containing a photoelectric conversion element; a transparent layer covering the plurality of pixels; and a plurality of structures arranged on or within the transparent layer in the plane direction of the transparent layer, wherein the plurality of structures include structures having different types of cross-sectional shapes when the transparent layer is viewed from above, and the plurality of structures are characterized in that they focus light of the color corresponding to the pixel from the light incident outside the region facing the pixel onto the pixel.

[0007] In one aspect, the image sensor comprises a plurality of pixels, each containing a photoelectric conversion element; a transparent layer covering the plurality of pixels; and a plurality of structures arranged on or within the transparent layer in the plane direction of the transparent layer, wherein the plurality of structures include structures having different types of cross-sectional shapes when the transparent layer is viewed from above, the plurality of pixels include a pixel unit consisting of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue arranged in a Bayer array, and among the plurality of structures, the plurality of structures arranged in the region opposite to one of the pixels corresponding to green in the pixel unit have an overall arrangement structure that is rotated by 90° from the overall arrangement structure of the plurality of structures arranged in the region opposite to the other pixel corresponding to green.

[0008] In one aspect, the image sensor comprises a plurality of pixels, each containing a photoelectric conversion element; a transparent layer covering the plurality of pixels; and a plurality of structures arranged on or within the transparent layer in the plane direction of the transparent layer, wherein the plurality of structures include structures having different types of cross-sectional shapes when the transparent layer is viewed from above, the plurality of pixels include a pixel unit arranged in a Bayer array, consisting of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue, and of the plurality of structures, the plurality of structures arranged in the region facing the pixel corresponding to red in the pixel unit have an overall arrangement structure that is rotationally symmetrical four times, and of the plurality of structures, the plurality of structures arranged in the region facing the pixel corresponding to blue in the pixel unit have an overall arrangement structure that is rotationally symmetrical four times.

[0009] In one aspect, the image sensor comprises a plurality of pixels, each containing a photoelectric conversion element; a transparent layer covering the plurality of pixels; and structures arranged on or within the transparent layer in the plane direction of the transparent layer. The plurality of pixels include a pixel unit arranged in a Bayer array, consisting of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue. The structure, located in a region facing one of the green pixels in the pixel unit, has an overall arrangement structure that is rotated 90° from the overall arrangement structure of the structure located in the region facing the other green pixel. The structure is characterized by focusing light of the color corresponding to that pixel from the light incident outside the region facing that pixel onto that pixel.

[0010] In one aspect, the image sensor comprises a plurality of pixels, each containing a photoelectric conversion element; a transparent layer covering the plurality of pixels; and structures arranged on or within the transparent layer in the plane direction of the transparent layer. The plurality of pixels include a pixel unit arranged in a Bayer array, consisting of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue. Of the structures, the structure arranged in the region facing the pixel corresponding to red in the pixel unit has an overall arrangement structure that is rotationally symmetrical four times, and the structure arranged in the region facing the pixel corresponding to blue in the pixel unit has an overall arrangement structure that is rotationally symmetrical four times. The structure is characterized by focusing light of the color corresponding to the pixel from the light incident outside the region facing that pixel onto that pixel.

[0011] The imaging device according to the present invention is characterized by comprising the above-mentioned image sensor and a signal processing unit that generates an image signal based on an electrical signal obtained from the image sensor. [Effects of the Invention]

[0012] According to the present invention, it becomes possible to reduce manufacturing costs. [Brief explanation of the drawing]

[0013] [Figure 1]FIG. 1 is a diagram showing an example of a schematic configuration of an imaging device and an imaging apparatus to which an optical element according to an embodiment is applied. [Figure 2] FIG. 2 is a diagram showing an example of a schematic configuration of an imaging device. [Figure 3] FIG. 3 is a diagram showing an example of a schematic configuration of an imaging device. [Figure 4] FIG. 4 is a diagram showing an example of a schematic configuration of an imaging device. [Figure 5] FIG. 5 is a diagram showing an example of a schematic configuration of an imaging device. [Figure 6] FIG. 6 is a diagram schematically showing the light condensation on corresponding pixels. [Figure 7] FIG. 7 is a diagram schematically showing the light condensation on corresponding pixels. [Figure 8] FIG. 8 is a diagram schematically showing the light condensation on corresponding pixels. [Figure 9] FIG. 9 is a diagram showing an example of the light intensity distribution on a pixel at each wavelength. [Figure 10] FIG. 10 is a diagram showing an example of the light intensity distribution on a pixel at each wavelength. [Figure 11] FIG. 11 is a diagram showing an example of the light intensity distribution on a pixel at each wavelength. [Figure 12] FIG. 12 is a diagram showing an example of a schematic configuration of a structure. [Figure 13] FIG. 13 is a diagram showing an example of a schematic configuration of a structure. [Figure 14] FIG. 14 is a diagram showing an example of a schematic configuration of a structure. [Figure 15] FIG. 15 is a diagram showing an example of a schematic configuration of a structure. [Figure 16] FIG. 16 is a diagram showing an example of a schematic configuration of a structure. [Figure 17] FIG. 17 is a diagram showing an example of a schematic configuration of a structure. [Figure 18] FIG. 18 is a diagram showing an example of a combination of each wavelength and the amount of optical phase delay. [Figure 19] FIG. 19 is a diagram showing an example of a combination of each wavelength and the amount of optical phase delay. [Figure 20]Figure 20 shows an example of a lens design. [Figure 21] Figure 21 shows an example of a lens design. [Figure 22] Figure 22 shows an example of a lens design. [Figure 23] Figure 23 shows an example of a lens design. [Figure 24] Figure 24 shows an example of a lens design. [Figure 25] Figure 25 shows an example of a lens design. [Figure 26] Figure 26 shows an example of a lens design. [Figure 27] Figure 27 shows an example of a lens design. [Figure 28] Figure 28 shows an example of a lens design. [Figure 29] Figure 29 shows an example of a lens design. [Figure 30] Figure 30 shows an example of a lens design. [Figure 31] Figure 31 shows an example of a lens design. [Figure 32] Figure 32 shows an example of a lens design. [Figure 33] Figure 33 shows an example of a lens design. [Figure 34] Figure 34 shows an example of a lens design. [Figure 35] Figure 35 shows an example of a lens design. [Figure 36] Figure 36 shows an example of a lens design. [Figure 37] Figure 37 shows an example of a lens design. [Figure 38] Figure 38 shows an example of a lens design. [Figure 39] Figure 39 shows an example of a lens design. [Figure 40] Figure 40 shows an example of the spectrum of light incident on a pixel. [Figure 41]Figure 41 shows an example of the intensity distribution of light incident on a pixel. [Figure 42] Figure 42 shows an example of the intensity distribution of light incident on a pixel. [Figure 43] Figure 43 shows an example of the intensity distribution of light incident on a pixel. [Figure 44] Figure 44 shows an example of the spectrum of light incident on a pixel. [Figure 45] Figure 45 shows an example of the intensity distribution of light incident on a pixel. [Figure 46] Figure 46 shows an example of the intensity distribution of light incident on a pixel. [Figure 47] Figure 47 shows an example of the intensity distribution of light incident on a pixel. [Figure 48] Figure 48 shows an example of the dependence on the angle of incidence. [Figure 49] Figure 49 shows an example of the dependence on the angle of incidence. [Figure 50] Figure 50 shows an example of the dependence on the angle of incidence. [Figure 51] Figure 51 shows an example of the dependence on the angle of incidence. [Figure 52] Figure 52 shows an example of the dependence on the angle of incidence. [Figure 53] Figure 53 shows an example of the dependence on the angle of incidence. [Figure 54] Figure 54 shows an example of the dependence on the angle of incidence. [Figure 55] Figure 55 shows an example of the dependence on the angle of incidence. [Figure 56] Figure 56 shows an example of the dependence on the angle of incidence. [Figure 57] Figure 57 shows an example of the dependence on the angle of incidence. [Figure 58] Figure 58 shows an example of the dependence on the angle of incidence. [Figure 59] Figure 59 shows an example of the dependence on the angle of incidence. [Figure 60] Figure 60 shows an example of the dependence on the angle of incidence. [Figure 61]Figure 61 shows an example of the dependence on the angle of incidence. [Figure 62] Figure 62 shows an example of the dependence on the angle of incidence. [Figure 63] Figure 63 shows an example of the dependence on the angle of incidence. [Figure 64] Figure 64 shows an example of the dependence on the angle of incidence. [Figure 65] Figure 65 shows an example of the dependence on the angle of incidence. [Figure 66] Figure 66 shows an example of the dependence on the angle of incidence. [Figure 67] Figure 67 shows an example of a schematic configuration of an image sensor according to a modified example. [Figure 68] Figure 68 shows an example of a schematic configuration of an image sensor according to a modified example. [Figure 69] Figure 69 shows an example of a cross-sectional shape of a structure. [Figure 70] Figure 70 shows an example of a schematic configuration of an image sensor according to a modified example. [Figure 71] Figure 71 shows an example of a schematic configuration of an image sensor according to a modified example. [Figure 72] Figure 72 shows an example of the spectrum of light incident on a pixel. [Figure 73] Figure 73 shows an example of the spectrum of light incident on a pixel. [Figure 74] Figure 74 shows an example of the dependence on the angle of incidence. [Figure 75] Figure 75 shows an example of the dependence on the angle of incidence. [Figure 76] Figure 76 shows an example of the dependence on the angle of incidence. [Figure 77] Figure 77 shows an example of the dependence on the angle of incidence. [Figure 78] Figure 78 shows an example of the dependence on the angle of incidence. [Figure 79] Figure 79 shows an example of the dependence on the angle of incidence. [Figure 80] Figure 80 shows an example of the dependence on the angle of incidence. [Figure 81] Figure 81 shows an example of the dependence on the angle of incidence. [Figure 82] Figure 82 shows an example of the dependence on the angle of incidence. [Figure 83] Figure 83 shows an example of the dependence on the angle of incidence. [Figure 84] Figure 84 shows an example of the dependence on the angle of incidence. [Figure 85] Figure 85 shows an example of the dependence on the angle of incidence. [Figure 86] Figure 86 shows an example of the dependence on the angle of incidence. [Figure 87] Figure 87 shows an example of the dependence on the angle of incidence. [Figure 88] Figure 88 shows an example of the dependence on the angle of incidence. [Figure 89] Figure 89 shows an example of the dependence on the angle of incidence. [Figure 90] Figure 90 shows an example of the dependence on the angle of incidence. [Figure 91] Figure 91 shows an example of the dependence on the angle of incidence. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the drawings. The shapes, sizes, and positional relationships shown in the drawings are approximate and do not limit the present invention. The same parts are denoted by the same reference numerals, and redundant descriptions are omitted.

[0015] Figure 1 shows an example of a schematic configuration of an image sensor and imaging device using an optical element according to the embodiment. The imaging device 10 uses light from the object 1 (subject), indicated by a white arrow, as incident light to image the object 1. The incident light enters the image sensor 12 via the lens optical system 11. The signal processing unit 13 processes the electrical signal from the image sensor 12 to generate an image signal.

[0016] Figures 2 to 5 show examples of the schematic configuration of an image sensor. In the figures, the XYZ coordinate system is shown. The XY plane direction corresponds to the plane direction of the pixel layer 3, transparent layer 5, etc., which will be described later. Hereafter, unless otherwise specified, "planar view" refers to viewing in the Z-axis direction (for example, the negative Z-axis direction). "Side view" refers to viewing in the X-axis direction or the Y-axis direction (for example, the negative Y-axis direction).

[0017] The image sensor 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 Z-axis direction.

[0018] Figure 2 schematically shows the layout of pixel layer 3 when viewed from above. Pixel layer 3 is a pixel array containing multiple pixels arranged in the XY plane. Each pixel is composed of a photoelectric conversion element. An example of a photoelectric conversion element is a photodiode (PD). Each pixel corresponds to one of the colors: red (R), green (G), or blue (B). An example of the wavelength range for red light is 600 nm < λ0, where λ0 is the wavelength. An example of the wavelength range for green light is 500 nm < λ0 ≤ 600 nm. An example of the wavelength range for blue light is λ0 ≤ 500 nm. To distinguish each pixel by color, they are referred to as pixel R, pixel G1, pixel G2, and pixel B in the diagram. These four pixels R, G1, G2, and B are arranged in a Bayer array to form one pixel unit (color pixel unit).

[0019] Figure 3 shows an example of a cross-section of the image sensor 12 when viewed from the side along the line III-III' in Figure 2. Figure 4 shows an example of a cross-section of the image sensor 12 when viewed from the side along the line IV-IV' in Figure 2. In the figures, the arrows schematically indicate the light incident on the image sensor 12. The incident light travels along the negative Z-axis direction and reaches the pixel layer 3 via the optical element 4.

[0020] According to the principle described later, the optical element 4 focuses the red light from the incident light onto pixel R, the green light onto pixels G1 and G2, and the blue light onto pixel B. The charges generated in pixels R, G1, G2, and B are converted into electrical signals that form the basis of the pixel signals by transistors (not shown), etc., and output to the outside of the image sensor 12 via the wiring layer 2. Some of the wiring included in the wiring layer 2 is shown in the diagram.

[0021] The optical element 4 is provided so as to cover the pixel layer 3. An example of the optical element 4 is a metasurface. The metasurface is composed of multiple microstructures (corresponding to the structure 6 described later) having a width less than or equal to the wavelength of light. The metasurface may have a two-dimensional structure or a three-dimensional structure. By simply changing the parameters of the microstructures, the phase and light intensity can be controlled according to the characteristics of light (wavelength, polarization, angle of incidence). In the case of a three-dimensional structure, the degree of design freedom is improved compared to a two-dimensional structure.

[0022] The optical element 4 has two functions: a color separation function and a lens function. The color separation function is the function of separating incident light into light of each color (each wavelength band) (spectral function, light separation function). The lens function is the function of focusing light of each color to the corresponding pixel. In this example, the color separation function separates the incident light into red light, green light, and blue light. The lens function focuses the red light on pixel R, the green light on pixels G1 and G2, and the blue light on pixel B.

[0023] The optical element 4 includes a transparent layer 5 and a structure 6. The transparent layer 5 is provided on the pixel layer 3 so as to cover the pixel layer 3. The transparent layer 5 may have a refractive index lower than that of the structure 6. An example of the material for the transparent layer 5 is SiO2. The transparent layer 5 may be void, in which case the refractive index of the transparent layer 5 may be equal to that of air. The material of the transparent layer 5 may be a single material or a layer of multiple materials.

[0024] Multiple structures 6 are arranged on or within the transparent layer 5, for example, periodically (having a periodic structure) in the planar direction (XY plane direction) of the transparent layer 5. In this example, the structures 6 are provided on the transparent layer 5 on the side opposite to the pixel layer 3 (the positive Z-axis side) across the transparent layer 5. The multiple structures 6 may be arranged at equal or unequal intervals to facilitate design, etc. Each structure 6 is a nano-order-size microstructure with dimensions approximately the same as or smaller than the wavelength of incident light.

[0025] Figure 5 schematically shows an example of a cross-section of multiple structures 6 corresponding to the area enclosed by the dashed line V in Figure 2. The multiple structures 6 include multiple structures 61 (first structures), multiple structures 62 (second structures), and multiple structures 63 (third structures). When viewed from above, each of the multiple structures 61 has the same type (first type) of cross-sectional shape. The same type of cross-sectional shape includes cross-sectional shapes having different dimensions (length, width, etc.). Similarly, each of the multiple structures 62 has the same type (second type) of cross-sectional shape. Each of the multiple structures 63 has the same type (third type) of cross-sectional shape. The cross-sectional shape may be a four-fold rotationally symmetric shape. Such a cross-sectional shape may consist of, for example, at least one of a square shape, a cross shape, and a circular shape.

[0026] Structures 61, 62, and 63 have different types of cross-sectional shapes. In the example shown in Figure 5, the cross-sectional shape of structure 61 is square. The cross-sectional shape of structure 62 is X-shaped. The X-shaped shape is an example of a shape composed of a cross shape, and is a shape obtained by rotating a cross shape by 45° in plane. The cross-sectional shape of structure 63 is hollow rhombic. The hollow rhombic shape is an example of a shape composed of a square shape, and is a shape obtained by rotating a hollow square shape by 45° in plane.

[0027] Furthermore, by adopting shapes that are rotated 45° in-plane, such as X-shapes or rhombuses, the optical coupling between adjacent structures is weakened, making it easier to maintain the optical properties of each structure without being affected by adjacent structures. As a result, it becomes easier to reproduce the ideal phase delay distribution described later.

[0028] As described above, when pixels R, G1, G2, and B are arranged in a Bayer array, as can be seen from the comparison in Figures 2 and 5, the multiple structures 6 positioned in the region opposite pixel G1 (or pixel G2) have an overall arrangement structure that is a 90° rotation of the overall arrangement structure of the multiple structures 6 positioned in the region opposite pixel G2 (or pixel G1). This is because the arrangement of adjacent pixels R and B differs for pixels G1 and G2, respectively. By making the overall arrangement structure of the structures 6 above pixels G1 and G2 common, except for the 90° rotation, efficient light collection becomes possible even in complex color arrangements such as Bayer arrays.

[0029] Figures 6 to 8 schematically illustrate the focusing of light onto corresponding pixels. As indicated by the arrow in Figure 6, blue light is focused onto pixel B. In this example, not only light from above pixel B (positive Z-axis direction) but also light from above surrounding pixels is focused onto pixel B. That is, the multiple structures 6 (Figures 3 to 5) are arranged so that light of the color corresponding to pixel B, which is incident outside the region opposite pixel B, is also focused onto pixel B. This increases the amount of light received compared to when only light incident on the region opposite pixel B is focused onto pixel B.

[0030] As shown by the arrows in Figure 7, green light is focused onto pixels G1 and G2. In this example, not only the light above pixels G1 and G2, but also the light above the surrounding pixels is focused onto pixels G1 and G2. That is, the multiple structures 6 are arranged so that light of the color opposite to pixels G1 and G2, which is incident outside the region opposite to pixels G1 and G2, is also focused onto pixels G1 and G2. This makes it possible to increase the amount of light received compared to when only light incident in the region opposite pixels G1 and G2 is focused onto pixels G1 and G2.

[0031] As shown by the arrow in Figure 8, red light is focused onto pixel R. In this example, not only light from above pixel R, but also light from above surrounding pixels is focused onto pixel R. That is, the multiple structures 6 are arranged so that light of the color corresponding to pixel R, which is incident outside the region opposite pixel R, is also focused onto pixel R. This increases the amount of light received compared to when only light incident in the region opposite pixel R is focused onto pixel R.

[0032] Figures 9 to 11 show examples of light intensity distribution for each wavelength (examples of calculated results). Areas with high light intensity are shown brightly. As shown in Figure 9, blue light (wavelength λ0 = 430 nm in this example) is concentrated in pixel B. As shown in Figure 10, green light (wavelength λ0 = 525 nm in this example) is concentrated in pixels G1 and G2. As shown in Figure 11, red light (wavelength λ0 = 635 nm in this example) is concentrated in pixel R.

[0033] Figures 12 to 17 show examples of the schematic configuration of the structures. Figures 12 and 13 show examples of the schematic configuration of structure 61 in side view and top view. Figures 14 and 15 show examples of the schematic configuration of structure 62 in side view and top view. Figures 16 and 17 show examples of the schematic configuration of structure 63 in side view and top view. Hereinafter, structures 61, 62, and 63 may simply be referred to as "structure 61, etc."

[0034] The structure 61, etc., is a columnar structure extending in the Z-axis direction and is formed on the base 6a. Examples of materials for the columnar structure are TiO2 (refractive index 2.40) or SiN (refractive index 2.05). The base 6a constitutes the transparent layer below the columnar structure. The base 61a is, for example, part of an SiO2 substrate (refractive index 1.45). The sides and top of the structure 61, etc., are filled with air.

[0035] The width of the base 6a corresponding to each structure 61, etc., is referred to as width W and is shown in the figure. The width W of the base 6a gives the arrangement period of the structures 61, etc. Width W is set such that no diffracted light is generated on the transmission side, W ≤ (λ min It may be set to / n2). λ min n 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. An example of the width W (arrangement period of the structure 61, etc.) is 280 nm.

[0036] The height (length in the Z-axis direction) of the structure 61, etc., when viewed from the side is referred to as height H and is illustrated. The height H of the structure 61, etc., may be the same. Height H is set such that the structure 61, etc., can impart an optical phase delay (phase value) of 2π or more to the incident light, i.e., light traveling along the Z-axis direction, so H ≥ λ. r It may be set to / (n1-n0). Wavelength λ r n1 is the desired center wavelength in the longest wavelength band of the light wavelength range to be color-separated. n1 is the refractive index of the structure 61, etc. If the structure 61, etc. is TiO2, n1 = 2.40 and the height H is, for example, 1250 nm. If the structure 61, etc. is SiN, n1 = 2.05 and the height H is, for example, 1600 nm.

[0037] By designing the cross-sectional shape of structures such as 61 (including dimensional design), various combinations can be realized that provide different optical phase delay amounts for each color of light (for each wavelength of light). Diversifying the cross-sectional shape increases the number of combinations and further improves the degree of design freedom.

[0038] Figures 18 and 19 show examples of combinations of wavelength and optical phase delay. As an example of blue light, the optical phase delay for light with a wavelength of 430 nm (Phase@λ=430 nm (rad / π)) is shown. As an example of green light, the optical phase delay for light with a wavelength of 520 nm (Phase@λ=520 nm (rad / π)) is shown. As an example of red light, the optical phase delay for light with a wavelength of 635 nm (Phase@λ=635 nm (rad / π)) is shown.

[0039] The square plots show the amount of optical phase delay when the dimensions of the cross-sectional shape of structure 61, which has a square cross-section, are set to various values. The X-shaped plots show the amount of optical phase delay when the dimensions of the cross-sectional shape of structure 62, which has an X-shaped cross-section, are set to various values. The rhombus plots show the amount of optical phase delay when the dimensions of the cross-sectional shape of structure 63, which has a hollow rhombus cross-section, are set to various values. In all cases, the height H is constant. The black circle plots represent the ideal amount of optical phase delay in the lens design described later.

[0040] Figure 18 shows the optical phase delay when the structure 61 is made of TiO2. Figure 19 shows the optical phase delay when the structure 61 is made of SiN. As can be seen, by designing the cross-sectional shape of the structure 61, various combinations of light of each color (light of each wavelength) and the optical phase delay can be realized. In other words, even by using columnar structures of the same height H, diverse optical phase delay characteristics (phase characteristics) with different wavelength dispersions can be realized. This is because the wavelength dispersion characteristics of the resulting optical waveguide mode, optical resonance mode, and the resulting optical phase delay can be changed by the cross-sectional shape.

[0041] Based on the above principles, by designing the cross-sectional shape and arrangement of structures 61 and other elements arranged in the planar direction of the transparent layer 5, a lens function with different focal points for each wavelength can be realized. Furthermore, lens design is possible not only for cases with three wavelengths, but also for cases with two or more wavelengths.

[0042] An example of lens design will be described with reference to FIGS. 20 to 39. In lens design, the cross-sectional shape and arrangement of the structure 61 and the like are designed so as to realize an ideal optical phase retardation amount distribution (phase distribution). In the example described below, the cross-sectional shape and arrangement of the structure 61 and the like are designed according to the ideal optical phase retardation amount distribution for each center wavelength in the wavelength bands of red light, green light, and blue light, respectively. The pixel size is 1.68 μm × 1.68 μm. The focal length is 4.2 μm. The center wavelength corresponding to blue light is 430 nm. The center wavelength corresponding to green light is 520 nm. The center wavelength corresponding to red light is 635 nm.

[0043] If the ideal optical phase retardation amount distribution is φ, φ is represented by the following formula.

Equation

[0044] The ideal optical phase retardation amount distribution was set as a phase distribution that gives the following light condensing positions to pixel B, pixel G1, pixel G2, and pixel R, respectively. Note that the center positions of the four pixels (pixel unit) correspond to x = 0 and y = 0. Pixel B: X f = +0.84 μm, y f = -0.84 μm, Z f = 4.2 μm Pixel G1: X f = +0.84 μm, y f = +0.84 μm, Z f = 4.2 μm Pixel G2: X f = -0.84 μm, y f = -0.84 μm, Z f = 4.2 μm Pixel R: X f = -0.84 μm, y f = +0.84 μm, Z f= 4.2 μm φ is converted to fall within the range of 0 to 2π. For example, -0.5π and 2.5π are converted to 1.5π and 0.5π, respectively. The boundary region of the optical phase delay distribution was set so that the optical phase delay distribution at each center wavelength is symmetrical left-right and up-down (together with the adjacent lens) around the focusing position. The constant C may be optimized at each wavelength so as to minimize the error (difference from the ideal value) of the optical phase delay distribution. From the optical phase delay amount at each wavelength, the structure that best fits the optical phase delay distribution at each center wavelength (the structure that minimizes the error) was placed at the corresponding position.

[0045] Figures 20 to 29 show examples of lens designs when the structure 61 etc. is made of TiO2. Multiple structures 61 etc. are arranged as shown in Figure 20. The center position of the illustrated structure 61 etc. corresponds to x=0, y=0.

[0046] Figure 21 shows the ideal optical phase delay distribution (Phase(rad / π)) when the central wavelength is 430 nm (blue light). Figure 22 shows an example of the optical phase delay distribution in the X-axis direction at y = 0.98 μm. Figure 23 shows an example of the optical phase delay distribution in the X-axis direction at y = -0.98 μm. The dashed line (Ideal) shows the ideal optical phase delay distribution, and the plot (Designed) shows the optical phase delay distribution obtained by arranging the multiple structures 61 etc. shown in Figure 20 above.

[0047] Figure 24 shows the ideal optical phase delay distribution when the central wavelength is 520 nm (green light). Figure 25 shows an example of the optical phase delay distribution in the X-axis direction at y = 0.98 μm. Figure 26 shows an example of the optical phase delay distribution in the X-axis direction at y = -0.98 μm.

[0048] Figure 27 shows the ideal optical phase delay distribution when the central wavelength is 635 nm (red light). Figure 28 shows an example of the optical phase delay distribution in the X-axis direction at y = 0.98 μm. Figure 29 shows an example of the optical phase delay distribution in the X-axis direction at y = -0.98 μm.

[0049] As can be seen, a near-ideal optical phase delay distribution can be obtained at any of the central wavelengths of 430 nm, 520 nm, and 635 nm (blue light, green light, and red light).

[0050] Figures 30 to 39 show examples of lens designs when the structure 61 etc. is made of SiN. Multiple structures 61 etc. are arranged as shown in Figure 30.

[0051] Figure 31 shows the ideal optical phase delay distribution when the central wavelength is 430 nm (blue light). Figure 32 shows an example of the optical phase delay distribution in the X-axis direction at y = 0.98 μm. Figure 33 shows an example of the optical phase delay distribution in the X-axis direction at y = -0.98 μm.

[0052] Figure 34 shows the ideal optical phase delay distribution when the central wavelength is 520 nm (green light). Figure 35 shows an example of the optical phase delay distribution in the X-axis direction at y = 0.98 μm. Figure 36 shows an example of the optical phase delay distribution in the X-axis direction at y = -0.98 μm.

[0053] Figure 37 shows the ideal optical phase delay distribution when the central wavelength is 635 nm (red light). Figure 38 shows an example of the optical phase delay distribution in the X-axis direction at y = 0.98 μm. Figure 39 shows an example of the optical phase delay distribution in the X-axis direction at y = -0.98 μm.

[0054] As can be seen, a near-ideal optical phase delay distribution can be obtained at any of the central wavelengths of 430 nm, 520 nm, and 635 nm (blue light, green light, and red light).

[0055] The spectrum and intensity distribution of light incident on a pixel will be explained with reference to Figures 40 to 47.

[0056] Figure 40 shows an example of the spectrum of light incident on each pixel when the structure 61 etc. is TiO2. The spectrum is that of an unpolarized plane light wave incident perpendicularly to the substrate (XY plane). The distance from the bottom end of the structure 61 etc. (lens structure end) to the pixel layer 3 is 4.2 μm (lens focal length). The horizontal axis of the graph shows wavelength (Wavelength (nm)). The vertical axis shows the detected power. The detected power is (light intensity on the pixel) / (light intensity incident on the structure 61 etc.). For example, if half of the light incident on the structure 61 etc. is incident on the pixel, the detected power is 0.5.

[0057] Light is focused onto each pixel such that each pixel has a peak in the wavelength band of light corresponding to its color. The spectrum of light incident on pixel R is shown by graph line R. The spectra of light incident on pixels G1 and G2 are shown by graph lines G1 and G2. The spectrum of light incident on pixel B is shown by graph line B. As a comparative example, the upper limit of the light receiving efficiency of 0.2 when a general filter (color filter) is used instead of the optical element 4 according to the embodiment is shown as the filter limit (with Tmax=80%). This upper limit of light receiving efficiency of 0.2 is the value obtained by dividing a filter having a maximum transmittance of 80% at each wavelength into four pixels: pixel R, pixel G1, pixel G2, and pixel B (0.8 / 4=0.2).

[0058] Pixels R, G1, G2, and B all have peak values ​​greater than the upper limit of 0.2 in the comparative example, indicating that the amount of light received by each pixel is greater than in the comparative example. For example, at a wavelength of 430 nm indicated by marker MA, the light-receiving efficiency of pixel B is significantly higher than the upper limit of 0.2 in the comparative example. At a wavelength of 525 nm indicated by marker MB, the light-receiving efficiency of pixels G1 and G2 is also significantly higher than the upper limit of 0.2 in the comparative example. At a wavelength of 635 nm indicated by marker MC, the light-receiving efficiency of pixel R is also significantly higher than the upper limit of 0.2 in the comparative example.

[0059] The total transmittance, i.e. (sum of light intensity on all pixels) / (incident light intensity on structure 61, etc.), averaged over wavelengths from 400nm to 700nm, is 93.2%, which is significantly higher than the upper limit of ~33% when using a typical filter. This also indicates that the light receiving efficiency of pixels can be improved.

[0060] Figure 41 shows the intensity distribution of light at the wavelength of marker MA in Figure 40 (blue light). It can be seen that the distribution is concentrated in pixel B. Figure 42 shows the intensity distribution of light at the wavelength of marker MB in Figure 40 (green light). It can be seen that the distribution is concentrated in pixels G1 and G2. Figure 43 shows the intensity distribution of light at the wavelength of marker MC in Figure 40 (red light). It can be seen that the distribution is concentrated in pixel R.

[0061] Figure 44 shows an example of the light spectrum incident on each pixel when the structure 61 etc. is SiN. Similar to the case where the structure 61 etc. is SiO2 as described above, pixels R, G1, G2, and B all have peak values ​​greater than the upper limit of 0.2 in the comparative example, indicating that the amount of light received at the pixels is greater than in the comparative example. The total transmittance is 97.1%, which is significantly higher than the upper limit of ~33% when using a typical filter.

[0062] Figure 45 shows the intensity distribution of light at the wavelength of marker MA in Figure 44 (blue light). It can be seen that the distribution is concentrated in pixel B. Figure 46 shows the intensity distribution of light at the wavelength of marker MB in Figure 44 (green light). Note that the wavelength indicated by marker MB in this SiN case is 520 nm. It can be seen that the distribution is concentrated in pixels G1 and G2. Figure 47 shows the intensity distribution of light at the wavelength of marker MC in Figure 44 (red light). It can be seen that the distribution is concentrated in pixel R.

[0063] Figures 48 to 66 show examples of incidence angle dependence. Figures 48 to 58 show examples of incidence angle dependence when the structure 61 etc. is TiO2.

[0064] As previously explained, pixels R, G1, G2, and B are arranged as shown in Figure 48. In this case, the dependence on the incident angle, when the angle in the XZ plane with the Z axis direction set to 0° is defined as the incident angle, is shown in Figures 50 to 53. Figure 50 shows the light receiving efficiency of pixel R as a spectrum for each wavelength (μm) and each incident angle (degree), i.e., for each incident angle. Figure 51 shows the light receiving efficiency of pixel G1 as a spectrum for each incident angle. Figure 52 shows the light receiving efficiency of pixel G2 as a spectrum for each incident angle. Figure 53 shows the light receiving efficiency of pixel B as a spectrum for each incident angle. For pixels R, G1, G2, and B, there is no significant change in the spectrum within an incident angle range of approximately ±12°.

[0065] As shown in Figure 54, the dependence on the incident angle when the angle in the YZ plane with the Z-axis direction set to 0° is taken as the incident angle is shown in Figures 55 to 58. Figure 55 shows the light-receiving efficiency of pixel R as a spectrum for each incident angle. Figure 56 shows the light-receiving efficiency of pixel G1 as a spectrum for each incident angle. Figure 57 shows the light-receiving efficiency of pixel G2 as a spectrum for each incident angle. Figure 58 shows the light-receiving efficiency of pixel B as a spectrum for each incident angle. For pixels R, G1, G2, and B, there is no significant change in the spectrum within an incident angle range of approximately ±12°.

[0066] Figures 59 to 66 show examples of the dependence on the incident angle when the structure 61 etc. is made of SiN.

[0067] The incidence angle dependence in the XZ plane, as shown in Figure 49 explained earlier, is shown in Figures 59 to 62. Figure 59 shows the incidence angle dependence on pixel R. Figure 60 shows the incidence angle dependence on pixel G1. Figure 61 shows the incidence angle dependence on pixel G2. Figure 62 shows the incidence angle dependence on pixel B. In all pixels, no significant change occurs in the spectrum within an incidence angle range of approximately ±12°.

[0068] Figures 63 to 66 show the dependence on the incident angle in the YZ plane, as explained earlier in Figure 54. Figure 63 shows the dependence on the incident angle for pixel R. Figure 64 shows the dependence on the incident angle for pixel G1. Figure 65 shows the dependence on the incident angle for pixel G2. Figure 66 shows the dependence on the incident angle for pixel B. In all pixels, no significant change occurs in the spectrum within an incident angle range of approximately ±12°.

[0069] As described above, it was confirmed that the optical element has tolerance to an incident angle of at least ±12°. This means that even when imaging with an imaging lens having an NA (numerical aperture) of ~0.21, color errors are unlikely to occur. Considering that the NA of a typical imaging lens (telephoto) for smartphone cameras is around 0.2, the optical element 4 according to this embodiment may be usable in smartphone cameras and the like. Note that tolerance to the incident angle mainly depends on the focal length, so designing a lens with a shorter focal length will further widen the acceptable angle.

[0070] As explained above, the optical element 4 enables both lens functions. For example, conventional image sensors have a filter (e.g., a color filter) instead of an optical element 4. That is, a filter corresponding to the color of each pixel is provided to cover that pixel. In this case, since the filter absorbs light of wavelengths other than the transmission wavelength band, the amount of light remaining after passing through the filter is only about 1 / 3 of the amount of light incident on the filter, and the light reception efficiency decreases. In contrast, with the image sensor 12 according to this embodiment, as described above, the amount of light is maintained at a higher level (e.g., more than 90%), so the light reception efficiency is greatly improved.

[0071] Furthermore, some conventional technologies incorporate (integrate) microlenses on the opposite side of the pixel from the filter in order to increase the amount of light received (improve sensitivity) by improving the aperture ratio and reducing the dependence on the angle of incident light. In this case, the structure becomes more complex and manufacturing costs increase because it consists of at least two layers: a filter and a microlens. According to the optical element 4 of this embodiment, the color separation function and the lens function can be realized by the optical element 4 alone, so the structure can be simplified and manufacturing costs can be reduced. In addition, since multiple structures 6 can be arranged in-plane (in the XY plane) without gaps, the aperture ratio is increased compared to microlenses.

[0072] Returning to Figure 1, the signal processing unit 13 of the imaging device 10 will now be described. The signal processing unit 13 generates pixel signals based on electrical signals obtained from the image sensor 12. In order to obtain electrical signals, the signal processing unit 13 also controls the image sensor 12. Control of the image sensor 12 includes exposure of pixels of the image sensor 12, conversion of charge accumulated in the pixel layer 3 into electrical signals, and reading out the electrical signals.

[0073] Although one embodiment of the present disclosure has been described above, the optical element, image sensor, and imaging device according to the embodiment can be modified in various ways without departing from the spirit of the embodiment. Several modifications will be described below.

[0074] In the above embodiment, an example was described in which multiple structures 6 are provided on the transparent layer 5 on the opposite side of the pixel layer 3 from the transparent layer 5. However, the configuration of the transparent layer 5 and the multiple structures 6 is not limited thereto.

[0075] Figures 67 and 68 show examples of schematic configurations of image sensors according to modified examples. In the image sensor 12A illustrated in Figure 67, a plurality of structures 6 are provided within the transparent layer 5 in the optical element 4A. The structures 6 are embedded within the transparent layer 5 on the pixel layer 3 (on the PD). On the other hand, in the image sensor 12B illustrated in Figure 68, the transparent layer 5 in the optical element 4B includes a transparent substrate 5a and an air layer 5b. The plurality of structures 6 are provided on the transparent substrate 5a (supported by the transparent substrate 5a) so as to extend from the transparent substrate 5a toward the pixel layer 3 (in the negative Z-axis direction).

[0076] The cross-sectional shape of structure 6 is not limited to the shapes shown in Figure 5 and other figures described earlier. Figure 69 shows an example of the cross-sectional shape of the structure. Structure 6 may have various cross-sectional shapes as illustrated. The illustrated shapes are, for example, four-fold rotationally symmetric shapes obtained by combining square, cross, and circular shapes in various ways.

[0077] The image sensor may include a filter. Figures 70 and 71 show examples of schematic configurations of image sensors according to such modifications. The illustrated image sensor 12C includes a filter layer 7 provided between the pixel layer 3 and the optical element 4. Figure 70 shows an example of a cross-section of the image sensor 12C when viewed from the side along the line III-III', when the image sensor 12 in Figure 2 is replaced with the image sensor 12C. Figure 71 shows an example of a cross-section of the image sensor 12C when viewed from the side along the line IV-IV', when the image sensor 12 in Figure 2 is replaced with the image sensor 12C.

[0078] The filter layer 7 includes filter 7R, filter 7G1, filter 7G2, and filter 7B. Filter 7R is provided to cover pixel R and allows red light to pass through. Filter 7G1 is provided to cover pixel G1 and allows green light to pass through. Filter 7G2 is provided to cover pixel G2 and allows green light to pass through. Filter 7B is provided to cover pixel B and allows blue light to pass through. Examples of materials for filters 7R, 7G1, 7G2, and 7B are organic materials such as resin.

[0079] Light separated by color by the optical element 4 further passes through the filter layer 7 before reaching the pixel layer 3. Color separation by both the optical element 4 and the filter layer 7 suppresses spectral crosstalk (removing most of the unwanted other color components) compared to color separation by only one of them, improving color reproduction. Furthermore, since the incident light is separated by the optical element 4 before passing through the filter layer 7, the amount of light is not significantly reduced. Therefore, the light-receiving efficiency of the pixels is improved compared to a case where only the filter layer 7 is provided and the optical element 4 is absent.

[0080] Figures 72 and 73 show examples of light spectra incident on a pixel.

[0081] Figure 72 shows an example of the spectrum when the structure 61 etc. is TiO2. The light-receiving efficiency of pixel R is shown by the graph line Metalens×R filter (R). The light-receiving efficiency of pixels G1 and G2 is shown by the graph line Metalens×G filter (G1 or G2). The light-receiving efficiency of pixel B is shown by the graph line Metalens×R filter (B). As a comparative example, the light-receiving efficiency of pixel R when the optical element 4 is absent and only a general filter is provided is shown by the graph line R filter (R). The light-receiving efficiency of pixel G is shown by the graph line G filter (G1 or G2). The light-receiving efficiency of pixel B is shown by the graph line B filter (B).

[0082] The peak spectral values ​​of pixels R, G1, G2, and B are approximately 1.2 to 2.0 times higher than those of the comparative example, resulting in a greater light-receiving efficiency. The total transmittance is also 43.3%, significantly higher than the comparative example's 34.7% (approximately 1.25 times). Furthermore, the spectra of the light incident on each pixel are sharper than those of the comparative example, indicating a reduction in unwanted color components. This improves color reproduction.

[0083] Figure 73 shows an example of the spectrum when the structure 61 etc. is SiN. The peak values ​​of the spectra of pixels R, G1, G2, and B are about 1.2 to 2.0 times higher than those of the comparative example, resulting in a higher light receiving efficiency than the comparative example. The total transmittance is also 45%, significantly higher than the comparative example's 34.7% (about 1.30 times). Furthermore, compared to the comparative example, the spectrum of light incident on each pixel is sharper, indicating that unwanted other color components can be reduced. This improves color reproduction.

[0084] The dependence on the incident angle will be explained with reference to Figures 74 to 91. Figures 74 to 83 show examples of the dependence on the incident angle when structure 6 is TiO2.

[0085] The incidence angle dependence in the XZ plane, as shown in Figure 74, is shown in Figures 75 to 78. Figure 75 shows the incidence angle dependence on pixel R. Figure 76 shows the incidence angle dependence on pixel G1. Figure 77 shows the incidence angle dependence on pixel G2. Figure 78 shows the incidence angle dependence on pixel B. In all pixels, no significant change occurs in the spectrum within an incidence angle range of approximately ±12°.

[0086] The dependence of the incident angle in the YZ plane, as shown in Figure 79, is shown in Figures 80 to 83. Figure 80 shows the dependence of the incident angle on pixel R. Figure 81 shows the dependence of the incident angle on pixel G1. Figure 82 shows the dependence of the incident angle on pixel G2. Figure 83 shows the dependence of the incident angle on pixel B. In all pixels, no significant change occurs in the spectrum within an incident angle range of approximately ±12°.

[0087] Figures 84 to 91 show examples of the incidence angle dependence when the structure 61 etc. is made of SiN.

[0088] Figures 84 to 87 show the incidence angle dependence in the XZ plane, as explained earlier in Figure 74. Figure 84 shows the incidence angle dependence on pixel R. Figure 85 shows the incidence angle dependence on pixel G1. Figure 86 shows the incidence angle dependence on pixel G2. Figure 87 shows the incidence angle dependence on pixel B. In all pixels, no significant change occurs in the spectrum within an incidence angle range of approximately ±12°.

[0089] The dependence on the incident angle in the YZ plane, as shown in Figure 79 explained earlier, is shown in Figures 88 to 91. Figure 88 shows the dependence on the incident angle for pixel R. Figure 89 shows the dependence on the incident angle for pixel G1. Figure 90 shows the dependence on the incident angle for pixel G2. Figure 91 shows the dependence on the incident angle for pixel B. In all pixels, no significant change occurs in the spectrum within an incident angle range of approximately ±12°.

[0090] As explained above, the image sensor 12C, which also includes a filter layer 7, can improve light reception efficiency and further enhance color reproduction.

[0091] In the above embodiment, TiO2 and SiN were used as examples of materials for the structure 6. However, the material for the structure 6 is not limited to these. For example, for light with a wavelength of 380 nm to 1000 nm (visible light to near-infrared light), in addition to SiN, SiC, TiO2, GaN, etc. may be used as materials for the structure 6. These are suitable because they have a high refractive index and low absorption loss. When used with light with a wavelength of 800 to 1000 nm (near-infrared light), Si, SiC, SiN, TiO2, GaAs, GaN, etc. may be used as materials for the structure 6. These are suitable because they have low loss. For light in the long-wavelength near-infrared region (communication wavelengths such as 1.3 μm and 1.55 μm), in addition to the materials mentioned above, InP, etc., can be used as materials for the structure 6.

[0092] When structure 6 is formed by bonding, coating, etc., examples of materials include polymers such as polyimides such as fluorinated polyimides, BCB (benzocyclobutene), photocurable resins, UV epoxy resins, acrylic resins such as PMMA, and general resists.

[0093] In the above embodiment, examples were shown in which SiO2 and an air layer were assumed as the material for the transparent layer 5, but it is not limited to these. Any material that has a refractive index lower than the refractive index of the material for the structure 6 and has low loss with respect to the wavelength of incident light is acceptable, including general glass materials. The transparent layer 5 only needs to have sufficiently low loss with respect to the wavelength of light that should reach the corresponding pixel, so it may be made of the same material as the color filter, or it may be an organic material such as resin. In this case, the transparent layer 5 may not only be made of the same material as the color filter, but may also have the same structure as the color filter and be designed to have absorption characteristics corresponding to the wavelength of light that should be guided to the corresponding pixel.

[0094] In the above embodiment, the three primary colors RGB were used as an example to describe the corresponding colors of the pixels, but pixels may also correspond to light of wavelengths other than the three primary colors (for example, infrared light, ultraviolet light, etc.).

[0095] In the above embodiment, an example was described in which structures having three different cross-sectional shapes, structure 61, structure 62, and structure 63, are used. However, two types of structures (for example, only structure 61 and structure 62) may be used, or four or more types of structures may be used.

[0096] Although the present invention has been described above based on specific embodiments, it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways without departing from its essence.

[0097] The technology described above can be identified, for example, as follows: As explained with reference to Figures 1 to 5, Figure 67 and Figure 68, the optical element 4 comprises a transparent layer 5 for covering a plurality of pixels (pixels R, etc.), each containing a photoelectric conversion element, and a plurality of structures 6 arranged on or within the transparent layer 5 in the plane direction (XY plane direction) of the transparent layer 5. The plurality of structures 6 are arranged to focus the incident light of a color (e.g., red, green, and blue) corresponding to each of the plurality of pixels onto the corresponding pixels. The plurality of structures 6 include structures (e.g., structure 61, structure 62, and structure 63) having different types of cross-sectional shapes (e.g., square shape, X shape, and hollow rhombus shape) when the transparent layer 5 is viewed from above (viewed in the Z-axis direction).

[0098] The optical element 4 described above combines both color separation and lens (light-gathering) functions. Therefore, it is possible to significantly improve the light-receiving efficiency of pixels and enhance light-receiving sensitivity compared to cases where, for example, a filter (e.g., a color filter) corresponding to each pixel is provided, or even microlenses are provided. Since the structure is simplified, manufacturing costs can also be reduced. Because multiple structures 6 can be arranged in the plane without gaps, the aperture ratio is also increased compared to microlenses.

[0099] As explained with reference to Figures 12 to 17, each of the multiple 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 to the incident light according to its cross-sectional shape. As explained with reference to Figures 20 to 39, the multiple structures 6 may be arranged according to the optical phase delay amount distribution for achieving the above-mentioned light focusing. For example, such an arrangement of multiple structures 6 can realize both a color separation function and a lens function.

[0100] As explained with reference to Figures 5 and 69, the cross-sectional shape of each of the multiple structures 6 may be a four-fold rotationally symmetric shape. This makes it possible to avoid polarization dependence.

[0101] As explained with reference to Figures 6 to 8, the multiple structures 6 may be arranged so as to focus the light of the color corresponding to that pixel, which is incident on the outside of the region opposite that pixel, onto that pixel. This increases the amount of light received compared to when only the light incident on the region opposite that pixel is focused onto that pixel.

[0102] As explained with reference to Figures 2 and 5, the multiple pixels include a pixel unit consisting of one pixel R corresponding to red, two pixels G1 and G2 corresponding to green, and one pixel B corresponding to blue, arranged in a Bayer array. Among the multiple structures 6, the multiple structures 6 arranged in the region opposite one of the pixels corresponding to green (e.g., pixel G1) in the pixel unit may have an overall arrangement structure that is rotated by 90° from the overall arrangement structure of the multiple structures arranged in the region opposite the other pixel corresponding to green (e.g., pixel G2). By making the overall arrangement structure of the multiple structures 6 common except for the 90° rotation, efficient light collection becomes possible even in complex color arrangements such as Bayer arrays.

[0103] The image sensor 12 described with reference to Figures 1 to 5 is also one embodiment of the present disclosure. The image sensor 12 comprises an optical element 4 and a plurality of pixels (pixels R, etc.) covered with a transparent layer 5. As explained earlier, this makes it possible to reduce manufacturing costs. It also makes it possible to improve light-receiving sensitivity and increase the aperture ratio.

[0104] As explained with reference to Figures 70 and 71, the image sensor 12C may include a filter layer 7 provided between multiple pixels (pixels R, etc.) and the transparent layer 5. This improves light reception efficiency and further enhances color reproduction.

[0105] The imaging device 10 described with reference to Figure 1, etc., is also one embodiment of the present disclosure. The imaging device 10 comprises the image sensor 12 described above and a signal processing unit 13 that generates an image signal based on pixel signals based on electrical signals obtained from the image sensor 12. As explained earlier, this makes it possible to reduce manufacturing costs. It is also possible to improve light receiving sensitivity and increase the aperture ratio. [Explanation of symbols]

[0106] 3 pixel layers 4 Optical elements 5 Transparent layer 6 Structure 7 Filter Layers 10 Imaging device 11 Lens Optics 12 Image sensor 61 Structure 62 Structure 63 Structure R pixel G1 pixels G2 pixels B pixels

Claims

1. Each of them contains multiple pixels including a photoelectric conversion element, A transparent layer covering the plurality of pixels, A plurality of structures arranged on or within the transparent layer in the plane direction of the transparent layer, Equipped with, The plurality of structures include structures having different types of cross-sectional shapes when the transparent layer is viewed from above, The plurality of structures are characterized by focusing light of a color corresponding to a single pixel onto that single pixel from among the light incident outside the region opposite a single pixel. Image sensor.

2. Each of them contains multiple pixels including a photoelectric conversion element, A transparent layer covering the plurality of pixels, A plurality of structures arranged on or within the transparent layer in the plane direction of the transparent layer, Equipped with, The plurality of structures include structures having different types of cross-sectional shapes when the transparent layer is viewed from above, The plurality of pixels include a pixel unit arranged in a Bayer array, consisting of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue. Among the plurality of structures, the plurality of structures arranged in the region opposite to one pixel corresponding to the green color in the pixel unit are characterized in that they have an overall arrangement structure obtained by rotating the overall arrangement structure of the plurality of structures arranged in the region opposite to the other pixel corresponding to the green color by 90°. Image sensor.

3. Each of them contains multiple pixels including a photoelectric conversion element, A transparent layer covering the plurality of pixels, A plurality of structures arranged on or within the transparent layer in the plane direction of the transparent layer, Equipped with, The plurality of structures include structures having different types of cross-sectional shapes when the transparent layer is viewed from above, The plurality of pixels include a pixel unit arranged in a Bayer array, consisting of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue. Of the plurality of structures, the plurality of structures arranged in the region opposite to the pixel corresponding to the red color in the pixel unit have an overall arrangement structure that is rotationally symmetrical four times. Among the plurality of structures, the plurality of structures arranged in the region opposite to the pixel corresponding to the blue color in the pixel unit are characterized in that they have an overall arrangement structure that is rotationally symmetrical four times. Image sensor.

4. Each of them contains multiple pixels including a photoelectric conversion element, A transparent layer covering the plurality of pixels, A structure arranged on or within the transparent layer in the plane direction of the transparent layer, Equipped with, The plurality of pixels include a pixel unit arranged in a Bayer array, consisting of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue. Among the aforementioned structures, the structure located in the region opposite to one pixel corresponding to the green color in the pixel unit has an overall arrangement structure obtained by rotating the overall arrangement structure of the structure located in the region opposite to the other pixel corresponding to the green color by 90°. The structure is characterized by focusing light of a color corresponding to a single pixel onto that single pixel from among the light incident outside the region opposite a single pixel. Image sensor.

5. Each of them contains multiple pixels including a photoelectric conversion element, A transparent layer covering the plurality of pixels, A structure arranged on or within the transparent layer in the plane direction of the transparent layer, Equipped with, The plurality of pixels include a pixel unit arranged in a Bayer array, consisting of one pixel corresponding to red, two pixels corresponding to green, and one pixel corresponding to blue. Of the aforementioned structures, the structure arranged in the region opposite to the pixel corresponding to the red color in the pixel unit has an overall arrangement structure that is rotationally symmetrical four times. Of the aforementioned structures, the structure arranged in the region opposite to the pixel corresponding to the blue color in the pixel unit has an overall arrangement structure that is rotationally symmetrical four times. The structure is characterized by focusing light of a color corresponding to a single pixel onto that single pixel from among the light incident outside the region opposite a single pixel. Image sensor.

6. Each of the plurality of structures is a columnar structure having a refractive index higher than that of the transparent layer, and giving an optical phase delay amount corresponding to the cross-sectional shape when the transparent layer is viewed in plan with respect to incident light. The aforementioned plurality of structures are arranged according to an optical phase delay distribution for achieving light focusing, Each of the aforementioned plurality of structures is characterized by having a cross-sectional shape that is four-fold rotationally symmetric. The image sensor according to any one of claims 1 to 3.

7. The aforementioned structure is a columnar structure having a refractive index higher than that of the transparent layer, and which provides an optical phase delay amount corresponding to the cross-sectional shape when the transparent layer is viewed in plan with respect to incident light. The aforementioned structure is arranged according to an optical phase delay distribution for achieving light focusing, The cross-sectional shape of the aforementioned structure is characterized by being four-fold rotationally symmetric. The image sensor according to claim 4 or 5.

8. The system is characterized by comprising a filter layer provided between the plurality of pixels and the transparent layer. The image sensor according to any one of claims 1 to 7.

9. An image sensor according to any one of claims 1 to 8, A signal processing unit that generates an image signal based on an electrical signal obtained from the image sensor, A feature comprising: Imaging device.

Images