Spectroscopic element array, imaging element, and imaging device

Abstract

A camera element of the present disclosure includes a two-dimensional pixel array in which a plurality of pixels including photoelectric conversion elements are arranged in an array on a substrate; a transparent layer formed on the two-dimensional pixel array; and a two-dimensional array of light-splitting elements in which a plurality of light-splitting elements are arranged in an array inside the transparent layer or on the transparent layer. Each light-splitting element includes a plurality of microstructures formed of a material having a higher refractive index than the refractive index of the transparent layer. The plurality of microstructures have a microstructure pattern. Each light-splitting element separates incoming light into first, second, third, and fourth deflected lights having different transmission directions, respectively, according to wavelength regions. First, second, third, and fourth pixels that are mutually adjacent and located directly below each light-splitting element detect the first, second, third, and fourth deflected lights, respectively.

Description

Technical Field

[0001] This invention relates to a beam splitter array, a camera element, and a camera device equipped with the camera element. Background Technology

[0002] Generally speaking, in camera elements equipped with photoelectric conversion elements such as CCD (Charge Coupled Device) sensors and CMOS (Complementary Metal Oxide Semiconductor) sensors, in order to obtain the color information of the image object, it is necessary to perform color separation of the incident light on each pixel, including the photoelectric conversion element.

[0003] Figure 1 The diagram shows a cross-sectional view of a typical color imaging element. In a conventional color imaging element 100, a photoelectric conversion element 102 is disposed on an electrical wiring 112, and a subtractive color filter 104, made of organic or inorganic materials, is disposed opposite to each pixel including the photoelectric conversion element 102. A microlens 103 is disposed on the color filter 104. When light enters from the microlens 103, the color filter 104 is used to transmit only the desired wavelength of light and absorb or reflect the unwanted wavelength of light. Thus, by acquiring signals from the three photoelectric conversion elements 102 corresponding to red (R), green (G), and blue (B) for each pixel, a color two-dimensional image can be generated.

[0004] However, in the general color imaging element 100 described above, there is a problem: when incident light has an RGB ratio of 1:1:1, the total amount of light transmitted through the color filter 104 inevitably becomes about 1 / 3. The remaining light lost is due to absorption or reflection by the color filter 104 and cannot be used for image formation. Therefore, the light utilization efficiency of the incident light is at most about 30%, which significantly limits the sensitivity of the imaging element. In recent years, with the progress of pixel miniaturization (high resolution of images), the amount of light received by a pixel inevitably decreases, and it is desirable to reduce the aforementioned limitation on the sensitivity of the imaging element.

[0005] As a means to reduce the limitations of image sensor sensitivity, a proposed approach is to use beam-splitting elements such as prisms and dichroic mirrors, which can branch incident light according to wavelength, instead of color filter 104, to construct the color image sensor. This approach can, in principle, significantly reduce incident light loss, thus greatly improving light utilization efficiency compared to using color filter 104. However, in recent years, with the miniaturization of pixels, it has become difficult to integrate beam-splitting elements such as prisms and dichroic mirrors onto photoelectric conversion elements while maintaining their functionality and characteristics.

[0006] Therefore, in recent years, the use of beam-splitting elements composed of microstructures that are relatively easy to integrate onto photoelectric conversion elements has been proposed to construct color imaging elements. In Non-Patent Literature 1, a method is proposed as follows: using two microstructures that can separate incident light into two wavelength regions, thereby eliminating the light loss from color separation in principle and improving light utilization efficiency.

[0007] exist Figure 2 (a) shows a top view of the color imaging element 200 proposed in Non-Patent Document 1. Figure 2 Section (b) shows its IIb-IIb sectional view, in Figure 2 (c) shows its IIc-IIc cross-sectional view. As shown, in the color imaging element 200, by replacing the color filter 104 and corresponding to the pixels (photoelectric conversion elements 102) with fine beam structures 206-1 and 206-2, the incident light is separated into direct light and left-right deflected light according to the wavelength region. This is because the phase delay effect experienced by the incident light within and around the fine beam structure is significantly different in one wavelength region and approximately equal in the other. Therefore, by alternately arranging two types of fine beam structures 206-1 and 206-2 with different structural thicknesses in rows on the two-dimensional pixel array, the four adjacent photoelectric conversion elements 102 can each receive light with different wavelength components. As a result, signal processing using matrix operations is performed on the photoelectric conversion signals output from each photoelectric conversion element 102 to generate color information, thereby generating a color image.

[0008] Furthermore, in Non-Patent Document 2, a method is proposed to improve light utilization efficiency by configuring a binary microstructure of fixed thickness that can separate incident light into three wavelength regions on a pixel (photoelectric conversion element 102).

[0009] exist Figure 3 (a) shows a top view of a color imaging element 300 with a micro-beam splitter 306 as proposed in Non-Patent Document 2. Figure 3 Section (b) shows its IIIb-IIIb cross-sectional view. Using the color imaging element 300 of Non-Patent Document 2, a color image can be generated by reconstructing color information through signal processing, similar to the case using the color imaging element 200 of Non-Patent Document 1. Furthermore, the light utilization efficiency of the color imaging element 300 of Non-Patent Document 2 is greater than that of the color imaging element 200 of Non-Patent Document 1. In addition, the color imaging element 200 of Non-Patent Document 2 does not exhibit the polarization dependence that is problematic in the color imaging element 200 of Non-Patent Document 1, and, being a binary structure, it has the advantage of being easy to manufacture.

[0010] Existing technical documents

[0011] Non-patent literature

[0012] Non-patent literature 1: Seiji Nishiwaki, Tatsuya Nakamura, Masao Hiramoto, Toshiya Fujii and Masa-aki Suzuki, "Efficient color splitters for high-pixel-densityimage sensors," Nature Photonics, Vol.7, March 2013, pp.240-246

[0013] Non-patent literature 2: Masashi Miyata, Mitsumasa Nakajima, Toshikazu Hashimoto, "High-Sensitivity Color Imaging Using Pixel-Scale Color Splitters Based on Dielectric Metasurfaces," ACS Photonics, March 2019, pp1442-1450

[0014] Non-patent literature 3: David Sell, Jianji Yang, Sage Doshay, Jonathan A.Fan, "Periodic Dielectric Metasurfaces with High-Efficiency,MultiwavelengthFunctionalities," Advanced Optical Materials, Vol.5, 2017, 1700645 Summary of the Invention

[0015] Non-Patent Documents 1 and 2 propose color reconstruction methods using signal processing as a method for generating color images. However, the technologies disclosed in Non-Patent Documents 1 and 2 have practical problems. These color image generation methods may produce color errors (noise) due to the signal processing, and the signal-to-noise ratio (SN ratio) of the image may deteriorate. Therefore, even if the light utilization efficiency, i.e., the amount of light received in the sensor, increases due to the beam splitter, the SN ratio of the captured image may not improve due to the addition of new noise caused by signal processing, and the substantial sensitivity may not be improved. Moreover, the additional signal processing time raises concerns about the reduction of temporal resolution. It should be noted that, as disclosed in Non-Patent Document 2, the following approach could be considered: setting the shape of a normally circular microlens to an ellipse, or setting the shape of a normally square pixel to a rectangle, etc., to directly obtain color information based on signal intensity without using signal processing. However, in addition to the fact that the change in the shape of the lens and pixel may not be suitable for existing manufacturing processes, post-processing, pixel configurations, etc., it may also interfere with the uniformity of the spatial resolution of the image, thus lacking feasibility. Furthermore, the beam-splitting elements disclosed in Non-Patent Documents 1 and 2 are elements that perform color separation of incident light only along one axis of the pixel array. Therefore, the effects of optical crosstalk between pixels are quite different on the color separation axis and on the axis perpendicular to it. Consequently, the resulting color image may have substantially different spatial resolutions on the two mutually perpendicular axes.

[0016] This disclosure was made in view of the aforementioned problems, and its object is to provide a camera element and camera device that are highly sensitive and can generate images with uniform spatial resolution without using signal processing-based color reconstruction.

[0017] To address the aforementioned problems, one embodiment of the imaging element of the present invention includes: a two-dimensional pixel array, comprising a plurality of pixels including photoelectric conversion elements arranged in an array on a substrate; a transparent layer formed on the two-dimensional pixel array; and a two-dimensional beam-splitting element array, comprising a plurality of beam-splitting elements arranged in an array inside or on the transparent layer, wherein each beam-splitting element includes a plurality of microstructures formed of a material having a refractive index higher than that of the transparent layer, the plurality of microstructures having a microstructure pattern, each beam-splitting element splits incident light in a two-dimensional direction, and the plurality of pixels respectively detect the light split in the two-dimensional direction. In one embodiment, in the above-described imaging element, each beam-splitting element separates incident light into first deflected light, second deflected light, third deflected light, and fourth deflected light with different transmission directions according to a wavelength region, and adjacent first pixels, second pixels, third pixels, and fourth pixels located directly below each beam-splitting element respectively detect the first deflected light, second deflected light, third deflected light, and fourth deflected light.

[0018] According to one embodiment of the present invention, by using a miniature beam-splitter capable of separating incident light into multiple wavelength regions along two axial directions of a plane, a high-sensitivity imaging element and imaging device can be achieved, generating images with uniform spatial resolution without using signal processing-based color reconstruction. Furthermore, the imaging element of one embodiment of the present invention is consistent with the widely used Bayer arrangement of pixel configurations, thus achieving high sensitivity by replacing the color filter with a miniature beam-splitter without making significant changes to the configuration of a typical color imaging element and its subsequent electronic circuitry. Attached Figure Description

[0019] Figure 1 It is a cross-sectional view of a typical color camera element.

[0020] Figure 2 (a) is a top view of the color imaging element proposed in Non-Patent Document 1. Figure 2 (b) is its IIb-IIb sectional view. Figure 2 (c) is its IIc-IIc sectional view.

[0021] Figure 3 (a) is a top view of the color imaging element proposed in Non-Patent Document 2. Figure 3 (b) is its IIIa-IIIb sectional view.

[0022] Figure 4 This is a side view showing a schematic configuration of a camera device 10 according to one embodiment of the present invention.

[0023] Figure 5 (a) is a schematic diagram showing a portion of the imaging element 500, including the pixel array and the beam-splitting element array, as viewed from the top surface. Figure 5 (b) is a schematic diagram showing its Vb-Vb cross-section. Figure 5 (c) is a schematic diagram showing its Vc-Vc cross section.

[0024] Figure 6 (a) is a schematic diagram showing a portion of the imaging element 600, including the pixel array and the beam-splitting element array, as viewed from the top surface. Figure 6 (b) is a schematic diagram showing its VIb-VIb cross section. Figure 6 (c) is a schematic diagram showing its VIc-VIc cross section.

[0025] Figure 7 (a) is a diagram showing the phase delay distribution of the wavelengths corresponding to the first wavelength region (R). Figure 7(b) is a diagram showing the phase delay distribution corresponding to the second wavelength region (G). Figure 7 (c) is a diagram showing the phase delay distribution of the wavelength corresponding to the third wavelength region (B).

[0026] Figure 8 (a) is a top view of an example of the microstructure constituting the micro-splitter 101 of this embodiment. Figure 8 (b) is a side view of an example of a microstructure.

[0027] Figure 9 (a) is a schematic diagram showing a portion of the imaging element 900, including the pixel array and the beam-splitting element array, as viewed from the top surface. Figure 9 (b) is a schematic diagram showing its IXb-IXb cross section. Figure 9 (c) is a schematic diagram showing its IXc-IXc cross section.

[0028] Figure 10 (a) is a schematic diagram showing a portion of the imaging element 900, including the pixel array and the beam-splitting element array, as viewed from the top surface. Figure 10 (b) is a schematic diagram showing its Xb-Xb cross-section. Figure 10 (c) is a schematic diagram showing its Xc-Xc cross section.

[0029] Figure 11 (a) is a diagram showing the phase delay distribution of the wavelengths corresponding to the first wavelength region (R). Figure 11 (b) is a diagram showing the phase delay distribution corresponding to the second wavelength region (G). Figure 11 (c) is a diagram showing the phase delay distribution of the wavelength corresponding to the third wavelength region (B). Figure 11 (d) is a diagram showing the phase delay distribution of wavelengths corresponding to the fourth wavelength region (IR). Detailed Implementation

[0030] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, it is understood that the following embodiments are merely examples, and the present invention is not limited to these embodiments.

[0031] Figure 4 This is a side view showing a schematic configuration of a camera device 10 according to one embodiment of the present invention. The camera device 10 includes: a lens optical system 11; an image sensor 12; and a signal processing unit 13, which processes the photoelectric conversion signal output from the image sensor 12 to generate an image signal.

[0032] Natural light, illumination light, and other light sources illuminate object 1, and the light transmitted / reflected / scattered by object 1, or light emitted from object 1, passes through the lens optical system 11 and forms an optical image on the imaging element 12, which includes photoelectric conversion elements such as CCD and CMOS. Typically, to correct various optical aberrations, the lens optical system consists of a lens group composed of multiple lenses arranged along the optical axis, but... Figure 4 The accompanying drawings are simplified to show a single lens. The signal processing unit 13 processes the photoelectric conversion signal output from the imaging element 12 to generate an image signal, and is capable of outputting the generated image signal to an external image signal output device. It should be noted that the imaging device 10 of the present invention may include known components such as an infrared light cutoff filter, an electronic shutter, a viewfinder, a power supply (battery), and a flash, but these descriptions are not particularly necessary for understanding the embodiments of the present invention and are therefore omitted. Furthermore, the above configuration is only an example. In one embodiment of the present invention, known components may be appropriately combined among the components other than the lens optical system 11, the imaging element 12, and the signal processing unit 13.

[0033] Before describing the details of the embodiments of the present invention, a general description of the imaging element 12 in the embodiments of the present invention will be given. The imaging element 12 of the embodiments of the present invention includes a micro-beam splitter 101 and pixels including a photoelectric conversion element 102. A plurality of pixels including the photoelectric conversion element 102 are arranged in a two-dimensional manner to form a pixel array. In addition, a plurality of micro-beam splitters 101 are arranged in a two-dimensional manner to form a beam splitter array. A portion of four mutually adjacent pixels is disposed at a corresponding position of a beam splitter. The corresponding position of a beam splitter refers to, for example, the state in which a portion of four mutually adjacent pixels including the pixel array overlaps with a projection surface falling onto the pixel array in the vertical direction from the area occupied by the beam splitter in the element surface.

[0034] As an example of the camera element 12, in Figure 5 (a) shows a portion of the configuration as seen from the upper surface of the imaging element 500, which includes a pixel array and a beam-splitting element array. Figure 5 Part of the configuration of the imaging element 500, shown in (b) with its Vb-Vb cross-section, is described. Figure 5 Part of the configuration of the imaging element 500 with its Vc-Vc cross-section is shown in (c). A beam-splitting element array is positioned opposite the pixel array. The beam-splitting element array is located on the side where light from the lens optical system 11 enters. A transparent layer 111 is provided between the beam-splitting element array and the pixel array, and on the lens optical system 11 side of the beam-splitting element array. Electrical wiring 112 (not shown) is provided on the opposite side of the beam-splitting element array of the pixel array.

[0035] Each micro-beam-splitter 101 constituting the beam-splitter array has a microstructure pattern with a fixed thickness (length in the z-axis direction). More specifically, each micro-beam-splitter 101 has a microstructure pattern with a fixed thickness but whose upper and lower surface shapes vary depending on their arrangement. It should be noted that the micro-beam-splitter 101 can also be a microstructure with varying thickness depending on its position. Furthermore, the microstructure pattern is not limited and various arrangements can be used. It should be noted that the imaging element 12 in the embodiments of the present invention can include known components such as microlenses and light-shielding walls, but these descriptions are not particularly necessary for understanding the general outline of the present invention; therefore, in… Figure 5 (a)~ Figure 5 (c) is omitted.

[0036] In this embodiment, the light incident on the imaging element 12 is classified into a first wavelength region, a second wavelength region, a third wavelength region, and a fourth wavelength region according to wavelength. It should be noted that the combination of the first to fourth wavelength regions is typically a combination of the three primary colors of red (R: peak intensity in the red wavelength region above 600 nm), green (G: peak intensity in the green wavelength region of 500 nm to 600 nm), and blue (B: peak intensity in the blue wavelength region below 500 nm) with near-infrared light (IR: peak intensity in the near-infrared wavelength region above 800 nm), but is not limited to this. For example, the combination of wavelength regions can be a combination of the three primary colors of red (R), green (G), and blue (B) with ultraviolet light (UV: peak intensity in the ultraviolet wavelength region below 380 nm), or a combination of multiple wavelength regions that are different in the infrared wavelength region, or a combination of multiple wavelength regions that are different in the ultraviolet wavelength region. Alternatively, the first to third wavelength regions can be set as different wavelength regions, and the fourth wavelength region can be set to be the same as one of the first to third wavelength regions. Each micro-beam splitter 101 constituting the beam splitter array in the embodiments of the present invention has the following function: utilizing the phase delay effect caused by the microstructure described later, as well as its structural size dependence and wavelength dependence, it thereby changes the transmission direction of light incident on the imaging element 12 according to the first to third wavelength regions or the first to fourth wavelength regions, causing the light to be spatially separated on the pixel array. That is, in the embodiments of the present invention, the light incident on the imaging element 12 is separated by each micro-beam splitter 101 in four directions: a first direction (upper right), a second direction (lower right), a third direction (lower left), and a fourth direction (upper left), and is incident on a portion of four adjacent pixels. As a more detailed example, the following scenario is illustrated: The micro-splitter 101 separates red (R) in a first direction (upper right); separates green (G) in a second direction (lower right); separates blue (B) in a third direction (lower left); and separates infrared (IR) in a fourth direction (upper left). Light in the wavelength region of red (R) is incident as light with a wide divergence width in the first direction (light with wavelength components arranged) into one of four adjacent pixels (the shorter wavelength light has a different angle of incidence than the longer wavelength light) to the pixel corresponding to red (adjacent to the pixel corresponding to green, and adjacent to the right side of the pixel corresponding to infrared). Light in the wavelength region of green (G) is incident as light with a wide divergence width in the second direction (light with wavelength components arranged) into the pixel corresponding to green (the shorter wavelength light has a different angle of incidence than the longer wavelength light) to the pixel corresponding to green (adjacent to the lower side of the pixel corresponding to red, and adjacent to the right side of the pixel corresponding to blue).Light in the blue (B) wavelength region, as light with a wide divergence width in the third direction (light with wavelength components arranged), is incident on the pixel corresponding to blue (adjacent to the left of the pixel corresponding to green, and adjacent to the bottom of the pixel corresponding to infrared light) (the incident angle of short-wavelength light is different from that of long-wavelength light). Light in the infrared (IR) wavelength region, as light with a wide divergence width in the fourth direction (light with wavelength components arranged), is incident on the pixel corresponding to infrared light (adjacent to the left of the pixel corresponding to red, and adjacent to the top of the pixel corresponding to blue) (the incident angle of short-wavelength light is different from that of long-wavelength light).

[0037] Furthermore, if four tiny beam-splitting elements 101 adjacent to the two axes of the plane (the x-axis and y-axis of the xy-plane) are designated as a beam-splitting unit (the beam-splitting unit is square), then the beam-splitting functions of the four tiny beam-splitting elements 101 constituting a beam-splitting unit are different from each other. Specifically, a beam-splitting unit includes four types of tiny beam-splitting elements. For example, the first type of tiny beam-splitting element has the following beam-splitting function: separating light in the first wavelength region, the second wavelength region, the third wavelength region, and the fourth wavelength region in the first direction (upper right), the second direction (lower right), the third direction (lower left), and the fourth direction (upper left), respectively. The second type of tiny beam-splitting element has the following beam-splitting function: separating light in the first wavelength region, the second wavelength region, the third wavelength region, and the fourth wavelength region in the second direction (lower right), the first direction (upper right), the fourth direction (upper left), and the third direction (lower left), respectively. The third type of micro-beam splitter has the following beam splitting function: it separates light into the first wavelength region, the second wavelength region, the third wavelength region, and the fourth wavelength region in the third direction (lower left), the fourth direction (upper left), the first direction (upper right), and the second direction (lower right), respectively. The fourth type of micro-beam splitter has the following beam splitting function: it separates light into the first wavelength region, the second wavelength region, the third wavelength region, and the fourth wavelength region in the fourth direction (upper left), the third direction (lower left), the second direction (lower right), and the first direction (upper right), respectively.

[0038] Therefore, the distance between the micro-beam splitter 101 and the pixel including the photoelectric conversion element 102 is set to the distance at which light enters the photoelectric conversion element 102 as follows: light separated by the micro-beam splitter 101 in the first direction (upper right); light separated by the micro-beam splitter adjacent to the right side of the micro-beam splitter 101 in the fourth direction (upper left); light separated by the micro-beam splitter adjacent to the upper right side of the micro-beam splitter 101 in the third direction (lower left); and light separated by the micro-beam splitter adjacent to the upper side of the micro-beam splitter 101 in the second direction (lower right). Thus, the four pixels (photoelectric conversion elements 102) located directly below each beam splitter unit receive light from only one region of the first, second, third, and fourth wavelength regions, respectively. When light enters the pixel, the photoelectric conversion element 102 outputs an electrical signal (photoelectric conversion signal) corresponding to the intensity of the incident light, thus directly acquiring the signal corresponding to the wavelength region (or color information if it is a primary color). The aforementioned micro-beam splitter 101 and the corresponding plurality of pixels (photoelectric conversion elements 102) are configured in a two-dimensional shape, thus enabling the simultaneous acquisition of information for each wavelength region of the optical image of an object formed by the lens optical system without the use of special signal processing. Furthermore, in this configuration, light is separated along the two axes of the plane, so the effects of optical crosstalk between any two pixels are equal, thereby enabling the generation of an image with uniform spatial resolution.

[0039] In the first embodiment described later, the first to third wavelength regions are designated as the three primary colors R, G, and B, and the fourth wavelength region is designated as the same as the second wavelength region. The incident light is spatially separated in four directions according to the wavelength regions of R, G, B, and G by the micro-beam splitter 101. That is, almost all the incident light is separated into the wavelength regions of R, G, and B and then enters the four adjacent pixels (photoelectric conversion elements 102) located directly below the micro-beam splitter 101. It should be noted that, for two of the four pixels, light from the same wavelength region is incident. Therefore, color information can be directly obtained from the photoelectric conversion signal obtained from the pixel (photoelectric conversion element 102).

[0040] Furthermore, in the second embodiment described later, the first to third wavelength regions are designated as the three primary colors R, G, and B, and the fourth wavelength region is designated as infrared (IR). The micro-beam splitter 101 spatially separates the incident light in four directions according to the wavelength regions of R, G, B, and IR. That is, almost all the incident light is incident on the four adjacent pixels (photoelectric conversion elements 102) located directly below the micro-beam splitter 101 while separated into the wavelength regions of R, G, B, and IR. It should be noted that, for each of the four pixels, light from a different wavelength region is incident. Therefore, color information and IR information can be directly obtained from the photoelectric conversion signals obtained from the pixels (photoelectric conversion elements 102).

[0041] The imaging element 12 according to an embodiment of the present invention can acquire information of each wavelength region of an object's optical image without special signal processing by using light separation of wavelength regions by a micro-beam splitter 101 without using a light-reducing bandpass filter. That is, if the first to fourth wavelength regions are set to the three primary colors R, G, B, and G, a color image can be acquired. Therefore, compared with imaging elements using color filters, the total amount of light reaching the pixel array can be increased, thereby improving the sensitivity of color imaging. Furthermore, if the first to fourth wavelength regions are set to the three primary colors R, G, B and IR, an IR image can be acquired simultaneously with high sensitivity in addition to a color image. Moreover, by acquiring information of each wavelength region through light separation along the two axes of the plane on the pixel array, the effect of optical crosstalk between any pixels is equal, and an image with uniform spatial resolution can be generated, thus solving the problems in the technology disclosed in Non-Patent Documents 1 and 2. Moreover, the imaging element 12 of the embodiments of the present invention has the following advantages: it does not require changes to the commonly used microlens shape, pixel shape, Bayer configuration and other pixel configurations, so it has high consistency with existing manufacturing processes and imaging systems, and the effect can be obtained simply by replacing the filter with a tiny beam splitter.

[0042] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0043] (First Implementation)

[0044] The following is a general description of the configuration of the camera element in this embodiment.

[0045] This embodiment shows a method in which the first to third wavelength regions are set as the three primary colors R, G, and B, and the fourth wavelength region is set to be the same as the second region, so that the incident light is split into R, G, B, and G. However, the number of wavelength regions and the wavelength of each wavelength region are not limited to this. For example, at least one of the four wavelength regions can also be light of a wavelength other than the three primary colors (e.g., infrared light, ultraviolet light).

[0046] As an example of the imaging element 12 based on the first embodiment, in Figure 6 (a) schematically shows a portion of the general configuration as seen from the upper surface of the imaging element 600, which includes a pixel array and a beam-splitting element array. Figure 6 Part of the configuration of the imaging element 600 shown in (b) is its VIb-VIb cross-section. Figure 6Part of the configuration of the imaging element 600 with its VIc-VIc cross-section is shown in (c). A low-refractive-index transparent layer 111 made of SiO2 or the like and a plurality of microlenses 103 are stacked on a two-dimensional pixel array in which pixels, including photoelectric conversion elements 102, are arranged in an array. A micro-beam splitter 101 is embedded inside the low-refractive-index transparent layer 111.

[0047] The micro-splitter 101 comprises multiple microstructures formed from materials such as SiN and TiO2, which have a higher refractive index than the transparent layer 111. These microstructures are formed in a patterned manner. For convenience, in the following description, an orthogonal xyz coordinate system is defined as follows: the normal direction of the two-dimensional pixel array is set as the z-axis; the horizontal direction parallel to the two-dimensional pixel array is set as the x-axis; and the direction perpendicular to the x-axis parallel to the two-dimensional pixel array is set as the y-axis.

[0048] like Figure 6 (a)~ Figure 6 As shown in (c), microlenses 103, microbeam splitters 101, and pixels (photoelectric conversion elements 102) are arranged in a lattice pattern with the same period on the xy plane, forming arrays. A microbeam splitter 101 is positioned directly below each microlens 103. Furthermore, the microlens array and the microbeam splitter array are shifted along the x-axis and y-axis, respectively, by half the length of the array period (distance between centers), starting from the arrangement of the pixel array. The center of the microbeam splitter 101 is defined as the position of half the length of the array period in the x-axis direction from the boundary of the microbeam splitter adjacent in the x-axis direction, and the position of half the length of the array period in the y-axis direction from the boundary of the microbeam splitter adjacent in the y-axis direction. At this time, as... Figure 6 As shown in (a), the center of the micro-beam splitter 101 is located directly above the center of the quadrilateral formed by four adjacent pixels directly below the micro-beam splitter 101. The micro-beam splitter array is composed of micro-beam splitters 101, which spatially separate incident light into three wavelength regions (R, G, B) along four directions parallel to the x-axis ±45° on the plane. Furthermore, if four adjacent micro-beam splitters 101 are configured as a beam splitting unit 601 (in... Figure 6(a) can be represented by a rectangle with double-dotted lines, which can be seen as the beam-splitting units forming a lattice array for the micro-beam-splitting element array. The four adjacent micro-beam-splitting elements 101 constituting the beam-splitting unit are configured such that the four combinations of the three wavelength regions are different, and light of the same wavelength region is incident on the four pixels located directly below the unit. It should be noted that for two of the four pixels located directly below each micro-beam-splitting element 101, light of the same wavelength region is incident. The unit described above can also be formed by rotating a micro-beam-splitting element with the same beam-splitting function by 90°, or by flipping it, or it can be formed by four micro-beam-splitting elements 101 that respectively implement four beam-splitting functions. Figure 6 The beam splitting unit shown in (a) includes elements that have the following beam splitting functions: splitting the light of R (solid line) in a first direction (upper right), splitting the light of G (dashed line) in a second direction (lower right), splitting the light of B (single-dot dashed line) in a third direction (lower left), and splitting the light of G (dashed line) in a fourth direction (upper left). To the right, below, and lower right of the element, there are also elements formed by rotating the element counterclockwise by 90°, elements formed by rotating the element clockwise by 90°, and elements formed by flipping the element.

[0049] It should be noted that the above description, as an example, illustrates a two-dimensional pixel array composed of square pixels (photoelectric conversion element 102) arranged in an orthogonal lattice, but the arrangement, shape, and size of the pixels are not limited to the example shown in this figure. Furthermore, in Figure 6 (a)~ Figure 6 (c) is omitted, but a structure may be provided between the two-dimensional pixel array and the micro-beam splitter array, which acts as an internal microlens. The structure has a light-gathering function achieved by a concave-convex structure made of SiN, TiO2, etc., that acts to guide light from the micro-beam splitter 101 to the photoelectric conversion element 102 in the pixel. This structure has a refractive index higher than that of the transparent layer. Figure 6 (a)~ Figure 6 The structure shown in (c) can be fabricated using known semiconductor manufacturing techniques.

[0050] It should be noted that, Figure 6 (a)~ Figure 6 The imaging element 600 shown in (c) has a back-illuminated structure in which light enters from the opposite side of the wiring layer formed by the electrical wiring 112, but this embodiment is not limited to such a structure. For example, it may also have a front-illuminated structure in which light is received from one side of the wiring layer.

[0051] The function of each component of the camera element 600 in this embodiment will be explained below.

[0052] White light incident on the imaging element 600 is first focused by a microlens array, with almost all of the light passing through micro-beam splitters 101 corresponding to each microlens 103. Through each micro-beam splitter 101, the light is spatially separated into four directions according to three wavelength regions, and is received by four adjacent pixels (photoelectric conversion elements 102) located directly below each micro-beam splitter 101. Depending on the configuration of the beam splitter unit, each pixel in the pixel array located directly below the micro-beam splitter array receives light from any wavelength region of R, G, and B; therefore, each pixel corresponds to the detection of any color information among R, G, and B. It should be noted that... Figure 6 (a)~ Figure 6 Example (c) is an example of a Bayer configuration where four pixels are set as one pixel unit, and the four pixels correspond to the R, G, G, and B light respectively. Depending on the configuration of each micro-splitter 101, the combination of color components and transmission direction can be freely changed, and the configuration of the pixels corresponding to RGB also changes accordingly. Finally, photoelectric conversion is performed by the photoelectric conversion element 102 within each pixel, and the signal is output as an image signal including color information.

[0053] It should be noted that a structure may be provided between the pixel array and the micro-beam splitter 101, which acts as an internal microlens and has a light-gathering function achieved by a concave-convex structure composed of SiN, TiO2, etc. with a refractive index higher than that of the transparent layer. However, the micro-beam splitter 101 described later may have a lens function due to the phase delay distribution formed, so the internal microlens may be omitted.

[0054] The miniature beam splitter 101 of this embodiment will be described below.

[0055] In order for the micro-beam splitter 101 to spatially separate the incident light into three wavelength regions (R, G, B) along the four directions mentioned above, it is necessary to give the light transmitted through the micro-beam splitter 101 a different phase delay distribution according to each wavelength region, so as to change the light wavefront.

[0056] Figure 7 (a)~ Figure 7 (c) is an example of the phase delay distribution of the miniature beam-splitting element 101 that achieves the above-described beam-splitting characteristics. In this example, as... Figure 7 As shown in (a), the phase delay distribution corresponding to the wavelength of the first wavelength region (R) forms a distribution that increases linearly from 0 to 2π along the path from the lower left to the upper right, as... Figure 7As shown in (b), the phase delay distribution corresponding to the second wavelength region (G) forms a distribution where the phase delay decreases linearly from π to 0 from the upper left towards the center, and increases linearly from 0 to π from the center towards the lower right, as shown in (b). Figure 7 As shown in (c), the phase delay distribution corresponding to the wavelength of the third wavelength region (B) forms a distribution in which the phase delay increases linearly from 0 to 2π along the upper right to the lower left. For light transmitted through an element having such a phase delay distribution, the first wavelength region (R) is deflected along the upper right direction, the second wavelength region (G) along the upper left and lower right directions, and the third wavelength region (B) along the lower left direction, respectively. It should be noted that the above description is an example, and the combination of wavelength regions and transmission directions can be freely changed according to the phase delay distribution. A phase delay distribution like the one described above can be achieved by appropriately designing the material, quantity, shape, size, pattern, etc., of the microstructure as described below. That is, the micro-splitter 101 in this embodiment arranges the microstructure on a two-dimensional plane, imparting different wavefronts to the incident light according to the wavelength region, and spatially separating the color components.

[0057] Figure 8 (a) shows the upper surface of an example of the microstructure constituting the micro-spectral element 101 in this embodiment. Figure 8 (b) shows a side view of the microstructure. As an example of the microstructure, the columnar structure 121 is formed of a material such as SiN or TiO2, having a refractive index n1 that is higher than the refractive index n0 of the transparent layer 111, and the thickness h of the structure is set to be fixed. Furthermore, the bottom and top surfaces of the columnar structure 121 are square. Based on the refractive index difference between the transparent layer 111 and the columnar structure 121, the columnar structure 121 can be considered as an optical waveguide that traps light within the structure for transmission. Therefore, light incident from the top surface is strongly trapped and transmitted within the columnar structure 121, receiving effective refractive index n1 from the optical waveguide. eff A defined phase delay effect is emitted from the bottom side. Specifically, when the phase of light is taken as the length of the structure in the transparent layer 111, and the wavelength of the light in vacuum is set as λ, the phase delay φ of the columnar structure 121 is expressed by formula (1).

[0058] φ=(n eff -n0)×2πh / λ……(1)

[0059] The phase retardation φ varies depending on the wavelength λ of the light; therefore, within the same columnar structure 121, light can be imparted with different phase retardations depending on the wavelength region (color component). Furthermore, it is known that n eff It is a function of the width w of the columnar structure 121, taking n0 < n eff< the value of n1. Therefore, in Figure 8 In the examples shown in (a) and (b), a variety of combinations of phase retardation amounts corresponding to the wavelength λ of light can be set by changing the width w of the columnar structure 121. Furthermore, since the bottom and top surfaces of the columnar structure 121 are square, the optical properties, including the phase retardation effect, remain unchanged even when the polarization (polarization) direction of the incident light is changed.

[0060] Reference Figure 7 (a)~ Figure 7 (c) The width w of the columnar structure 121 is set according to its position in a manner suitable for the phase delay distribution described above, and multiple such structures are arranged on a two-dimensional plane, thereby realizing the micro-beam splitter in this embodiment. Furthermore, in the arrangement of each columnar structure 121 described above, in order to prevent the generation of unwanted diffraction light caused by the periodic structure, it is ideal to arrange them at intervals below the wavelength of light. It should be noted that in order to effectively deflect light, a phase delay distribution varying from 0 to 2π is suitable; therefore, in each wavelength region, the variable range of the phase delay amount of the columnar structure 121 with a fixed thickness preferably has 2π or more. Therefore, according to formula (1), when the desired center wavelength in the wavelength region on the longest wavelength side of the separated wavelength regions is set to λ... r Ideally, the thickness h of the structure should be set at h = λ. r / (n1-n0) and above. In the above example, the case where the bottom and top surfaces of the columnar structure 121 are squares was described, but it is not limited to this shape. That is, as long as the shape of the surface includes four rotational symmetries with the center of the surface as the axis of symmetry, there will be no polarization dependence on the beam splitting function, and the operation as an optical waveguide that brings phase delay effect will not be lost. Therefore, it is ideal to use a columnar structure with four rotational symmetries such as a square, hollow square, circle, hollow circle, or cross shape. A micro beam splitting element composed of such a microstructure with a fixed thickness is disclosed, for example, in Non-Patent Document 2.

[0061] Furthermore, the micro-beam splitter 101 in this embodiment is not limited to the columnar structure 121 described above, and various microstructures can be used. For example, a microstructure with a fixed thickness and a structural pattern optimized by a computer, as disclosed in Non-Patent Document 3, can form a phase delay distribution according to the wavelength region based on the same principle as described above, and can spatially separate color components. Moreover, according to Formula (1), by changing the thickness h of the structure other than the width w of the columnar structure 121, a more colorful combination corresponding to the wavelength λ of light can be set. Therefore, by setting the width w and thickness h of the microstructures according to their positions in a manner suitable for the phase delay distribution described above, and arranging multiple microstructures on a two-dimensional plane, the micro-beam splitter in this embodiment can also be realized.

[0062] The miniature spectrometer 101 with the above-mentioned spectroscopic function can be fabricated by performing thin film deposition and patterning using known semiconductor manufacturing techniques.

[0063] As described above, desired spectral characteristics can be imparted by appropriately designing the materials, quantity, shape, size, and pattern of the structures constituting the micro-beam splitters. As a result, as mentioned above, light in the desired wavelength region can be separated and directed to each pixel, and the signal corresponding to the wavelength region can be directly acquired based on the photoelectric conversion signal output from the photoelectric conversion element within each pixel. Furthermore, as long as the material constituting the micro-beam splitter is low-loss, almost no light loss occurs. Therefore, compared to imaging elements using filters from conventional techniques, the total amount of light reaching the pixel array can be dramatically increased, thereby improving the sensitivity of color imaging. Moreover, by acquiring information for each wavelength region through light separation along both planar axes on the pixel array, the effects of light crosstalk between any pixels are equal, enabling the generation of images with uniform spatial resolution. In addition, while this embodiment describes an imaging element using a single beam splitter array, an imaging element can also be implemented by overlapping multiple beam splitter arrays along the z-axis instead of a single beam splitter array. That is, the tiny beam-splitting elements 101 constituting a single beam-splitting element array can split the incident light in a two-dimensional direction (two-axis direction of the plane), and multiple tiny beam-splitting elements overlapping in the light transmission direction (z-axis direction) can also split the incident light in a two-dimensional direction. It should be noted that even if the beam-splitting performance of each tiny beam-splitting element is slightly different from the ideal performance described above, good color information can still be obtained by correcting and calculating the acquired signal according to the degree of performance difference.

[0064] It should be noted that after the color components are separated based on the micro-beam splitter, to minimize optical crosstalk between pixels in the pixel array, ideally, the separated light should be incident near the center of each pixel. Therefore, preferably, if the angle between the transmission direction of the light deflected by the micro-beam splitter and the normal direction of the pixel array is set to θ, and the period of the pixel array is set to P, then the distance between the output end of the micro-beam splitter and the photoelectric conversion element is 2. 0.5 The vicinity of P / tanθ.

[0065] The above description describes an imaging element that uses only a small beam splitter. Next, a variation using a subtractive color filter will be described.

[0066] exist Figure 9 Image (a) shows an imaging element 900 including a pixel array and a beam-splitting element array of a modified example of this embodiment. Figure 9 Part of the configuration of the imaging element 900 shown in (b) is the IXb-IXb cross section. Figure 9 (c) shows a portion of the configuration of the imaging element 900 in its IXc-IXc cross-section. (and) Figure 6 (a)~ Figure 6 The difference between the imaging element 600 shown in (c) is that color filters 104, each corresponding to the color of a pixel, are arranged above the pixels corresponding to the color components. R 104 G 104 B Everything else is the same. In this configuration, after the incident light is color-separated by the micro-beam splitter 101, it is filtered by the color filter 104 directly above the pixel (photoelectric conversion element 102). In this case, the light passes through the color filter 104 after color separation, thus improving light utilization efficiency compared to the conventional configuration of only a color filter. However, since the light needs to pass through two elements, the light utilization efficiency is reduced compared to the configuration of only the micro-beam splitter 101. Furthermore, the beam splitting characteristics of the micro-beam splitter 101 are multiplied by the filtering characteristics of the color filter 104, allowing unwanted color components to be further eliminated before entering each pixel. Therefore, the color reproducibility is significantly improved compared to the configurations of only the color filter 104 and only the micro-beam splitter 101. Thus, it can be said to be a configuration with a good balance between light utilization, i.e., sensitivity and color reproducibility.

[0067] (Second Implementation)

[0068] Next, a general description of the configuration of the imaging element in the second embodiment of the present invention will be given.

[0069] As an example of the camera element 12, in Figure 10 (a) schematically shows a portion of the general configuration as seen from the upper surface of the imaging element 1000, which includes a pixel array and a beam-splitting element array. Figure 10 Part of the configuration of the imaging element 1000, shown in (b) with its Xb-Xb cross-section, is described. Figure 10 Part of the configuration of the imaging element 1000, shown in (c) with its Xc-Xc cross-section, is illustrated. Figure 10 (a)~ Figure 10 As can be seen from (c), the difference between the imaging element 1000 and the imaging device 10 using the imaging element 1000 in this embodiment and the imaging element in the first embodiment is that the first to fourth wavelength regions are set as the three primary colors R, G, and B and infrared light (IR), and the incident light is spatially separated in four directions according to the wavelength regions of R, G, B, and IR by the micro-beam splitter 101. Therefore, almost all the incident light enters the four pixels (photoelectric elements 102) located directly below the micro-beam splitter 101 in the state of being separated into the wavelength regions of R, G, B, and IR. R 102 G 102 B 102 IR It should be noted that its constituent elements are the same as those of the imaging element in the first embodiment. The following description focuses on the differences from the first embodiment, omitting repeated points.

[0070] like Figure 10 (a)~ Figure 10 As shown in (c), microlenses 103, microbeam splitters 101, and pixels (photoelectric conversion elements 102) are arranged in a lattice pattern with the same period on the xy plane, forming arrays. A microbeam splitter 101 is positioned on the central axis of each microlens 103. Furthermore, the microlens array and the microbeam splitter array are shifted along the x-axis and y-axis by half the length of the array period, respectively, from the arrangement of the pixel array. The microbeam splitter array is composed of microbeam splitters 101, which spatially separate the incident light into four wavelength regions (R, G, B, IR) along four directions parallel to the x-axis at ±45°. Furthermore, if four adjacent microbeam splitters are considered as a single beam splitting unit (in... Figure 10(a) can be represented by a rectangle with double-dotted lines, which can be seen as the beam-splitting units forming a lattice array for the micro beam-splitting element array. The micro beam-splitting elements 101 constituting the beam-splitting unit are configured such that the combinations of the four directions allocated according to the four wavelength regions are different, and light of the same wavelength region is respectively incident on the four pixels located directly below the unit. It should be noted that, for the four pixels, light of different wavelength regions is incident on all of them. The above-mentioned unit can also be formed by rotating a micro beam-splitting element with the same beam-splitting function by 90°, or by flipping it, or it can be formed by four micro beam-splitting elements 101 that respectively realize four beam-splitting functions. Figure 10 The beam splitting unit shown in (a) includes elements that have the following beam splitting functions: splitting the light of R (solid line) in a first direction (upper right), splitting the light of G (dashed line) in a second direction (lower right), splitting the light of B (single-dot dashed line) in a third direction (lower left), and splitting the light of IR (double-dot dashed line) in a fourth direction (upper left). To the right, below, and lower right of the element, there are also elements formed by rotating the element counterclockwise by 90°, elements formed by rotating the element clockwise by 90°, and elements formed by flipping the element.

[0071] White light incident on the imaging element 1000 is first focused by a microlens array, with almost all of the light passing through micro-beam splitters 101 corresponding to each microlens 103. Through each micro-beam splitter 101, the light is spatially separated into four wavelength regions in four directions, and each light is received by one of the four pixels (photoelectric conversion elements 102) located directly below each micro-beam splitter 101. Depending on the configuration of the beam splitter unit, each pixel in the pixel array located directly below the micro-beam splitter array receives light from any wavelength region among R, G, B, and IR, thus each pixel corresponds to the detection of information in any of the R, G, B, and IR wavelength regions. It should be noted that the combination of wavelength region and transmission direction can be freely changed according to the configuration of each micro-beam splitter 101, and the configuration of the pixels corresponding to R, G, B, and IR also changes accordingly. Finally, photoelectric conversion is performed by the photoelectric conversion elements 102 within each pixel, and the signal is output as an image signal including color and IR information.

[0072] Figure 11 (a)~ Figure 11 (c) is an example of achieving a spatially separated phase delay distribution of incident light across four wavelength regions (R, G, B, IR). In this example, as... Figure 11 As shown in (a), the phase delay distribution corresponding to the wavelength of the first wavelength region (R) forms a distribution that increases linearly from 0 to 2π along the path from the lower left to the upper right, as... Figure 10As shown in (b), the phase delay distribution corresponding to the wavelength in the second wavelength region (G) forms a distribution in which the phase delay increases linearly from 0 to 2π from the upper left to the lower right, as... Figure 10 As shown in (c), the phase delay distribution corresponding to the wavelength in the third wavelength region (B) forms a distribution that increases linearly from 0 to 2π along the upper right to the lower left, as... Figure 10 As shown in (d), the phase delay distribution corresponding to the fourth wavelength region (IR) forms a distribution in which the phase delay increases linearly from 0 to 2π from the lower right to the upper left. For light transmitted through an element having such a phase delay distribution, the first wavelength region (R) is deflected along the upper right direction, the second wavelength region (G) along the lower right direction, the third wavelength region (B) along the lower left direction, and the fourth wavelength region (IR) along the upper left direction, respectively. It should be noted that the above description is an example, and the combination of wavelength regions and transmission directions can be freely changed according to the phase delay distribution. A phase delay distribution like the one described above, similar to that of the imaging element in the first embodiment, can be achieved by appropriately designing the material, quantity, shape, size, pattern, etc., of the microstructure.

[0073] In summary, in this embodiment, IR information can be acquired simultaneously in addition to color information. This embodiment is the same as the first embodiment except as described above, and has the same effects as the photographic element described in the first embodiment; furthermore, the same modifications can be made.

[0074] The first and second embodiments described above are merely preferred specific examples of the present invention. The present invention is not limited to these and various modifications can be made.

[0075] In the first and second embodiments described above, examples assuming SiN and TiO2 are used as materials for micro-beam splitters were shown, but the present invention is not limited thereto. For example, when the imaging element of the embodiments of the present invention is used in the visible light to near-infrared light region with wavelengths ranging from 380 to 1000 nm, materials such as SiN, SiC, TiO2, and GaN have high refractive indices and low absorption losses, and are therefore suitable as materials for micro-beam splitters. Furthermore, for near-infrared light with wavelengths ranging from 800 to 1000 nm, materials such as Si, SiC, SiN, TiO2, GaAs, and GaN are suitable as materials with low loss for these lights. Moreover, in the long-wavelength near-infrared region (such as 1.3 μm and 1.55 μm for communication wavelengths), in addition to the materials described above, InP and the like can also be used. Furthermore, when forming tiny spectral elements by pasting or coating, materials that can be used include polyimides such as fluorinated polyimides, BCB (benzocyclobutene), light-curing resins, UV epoxy resins, acrylic resins such as PMMA, and polymers such as photoresists.

[0076] Furthermore, in the first and second embodiments, examples are shown assuming that SiO2 is used as the material of the transparent layer 111, but the present invention is not limited thereto. Ordinary glass materials, SiO2, air layers, etc., are all acceptable, as long as the refractive index is lower than that of the material of the micro-beam splitter 101 and the loss to the wavelength of incident light is low.

[0077] The imaging element and the imaging device using the imaging element have been described above based on embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from its spirit.

Claims

1. A camera element, comprising: A two-dimensional pixel array is formed by arranging multiple pixels of a photoelectric conversion element in an array on a substrate; A transparent layer is formed on the two-dimensional pixel array; and A two-dimensional beam-splitting element array is formed by arranging multiple beam-splitting elements in an array inside or on the transparent layer, wherein... Each of the aforementioned beam-splitting elements comprises multiple microstructures formed of a material having a refractive index higher than that of the transparent layer. These microstructures have a microstructure pattern. Multiple beam-splitting element units are adjacent to each other in a two-dimensional direction. Each beam-splitting element unit consists of four beam-splitting elements within the two-dimensional beam-splitting element array. These four beam-splitting elements are adjacent to each other in a two-dimensional direction. The four beam-splitting elements in each beam-splitting element unit are beam-splitting elements formed by rotating or flipping a beam-splitting element by 90°. Each beam-splitting element splits the incident light in directions along two axes of the plane. The multiple pixels detect the light split in these two directions. Each of the aforementioned beam-splitting elements separates the incident light into first deflected light, second deflected light, third deflected light, and fourth deflected light, each with a different transmission direction, according to the wavelength region. The first, second, third, and fourth pixels, which are located directly below each of the beam splitting elements and are adjacent to each other, detect the first deflected light, the second deflected light, the third deflected light, and the fourth deflected light, respectively.

2. The imaging element according to claim 1, wherein, The center of each of the beam-splitting elements is located directly above the center of the quadrilateral formed by the first, second, third, and fourth pixels that are adjacent to each other and directly below the beam-splitting element. The wavelength regions of the first pixel, the second pixel, the third pixel, and the fourth pixel that are adjacent to each other correspond to the wavelength regions of the first deflected light, the second deflected light, the third deflected light, and the fourth deflected light detected by the first pixel, the second pixel, the third pixel, and the fourth pixel, respectively. The wavelength regions of at least three of the deflected lights—the first, the second, the third, and the fourth—are different from each other.

3. The imaging element according to claim 1, wherein, The thickness of the multiple microstructures in each of the beam splitting elements is fixed in the direction of light transmission.

4. The imaging element according to claim 1, wherein, The thickness of the multiple microstructures in each of the beam-splitting elements varies depending on their position in the direction of light transmission.

5. The imaging element according to claim 1, wherein, When the incident light is white light The light incident on the first pixel has a peak intensity in the blue wavelength region below 500nm. The light incident on the second pixel and the third pixel has a peak intensity in the green wavelength region of 500nm to 600nm. The light incident on the fourth pixel has a peak intensity in the red wavelength region above 600nm.

6. The imaging element according to claim 1, wherein, When the incident light is white light The light incident on the first pixel has a peak intensity in the blue wavelength region below 500nm. The light incident on the second pixel has a peak intensity in the green wavelength region of 500nm to 600nm. The light incident on the third pixel has a peak intensity in the red wavelength region of 600nm to 800nm. The light incident on the fourth pixel has a peak intensity in the near-infrared wavelength region above 800nm.

7. The imaging element according to claim 5, wherein, A filter array is also provided between the two-dimensional pixel array and the two-dimensional beam splitter array. The filter array includes at least one of the following filters: The first filter has a peak transmittance in the blue wavelength region below 500nm; The second filter has a peak transmittance in the green wavelength region of 500nm to 600nm. The third filter has a peak transmittance in the red wavelength region of 600nm to 800nm; and The fourth filter has a peak transmittance in the near-infrared wavelength region above 800nm.

8. A camera device, comprising: The imaging element according to any one of claims 1 to 7; A camera optical system for forming an optical image on the imaging surface of the camera element; and A signal processing unit that processes the electrical signals output by the camera element.

9. A beam-splitting element array, which is a two-dimensional beam-splitting element array formed by arranging multiple beam-splitting elements in an array inside or on a transparent layer, wherein, Each of the aforementioned beam-splitting elements comprises a plurality of microstructures formed of a material having a refractive index higher than that of the transparent layer. The plurality of microstructures have microstructure patterns. The plurality of beam-splitting element units are adjacent to each other in a two-dimensional direction. Each of the aforementioned beam-splitting element units is composed of four beam-splitting elements within the two-dimensional beam-splitting element array. The four beam-splitting elements are adjacent to each other in a two-dimensional direction. The four beam-splitting elements of each of the aforementioned beam-splitting element units are beam-splitting elements formed by rotating or flipping a beam-splitting element by 90°. Each of the aforementioned beam-splitting elements splits the incident light in a direction along two axes of the plane. Each of the aforementioned beam-splitting elements separates the incident light into a first deflected light, a second deflected light, a third deflected light, and a fourth deflected light, which have different transmission directions, according to the wavelength region.

Images