Color image sensor and imaging device

Abstract

To provide a highly sensitive color image sensor and imaging device that integrates a micro-spectroscopic element, which can be easily fabricated, has low polarization dependence, and can separate incident light into three wavelength regions, with a two-dimensional pixel array. [Solution] The image sensor 100 has a two-dimensional pixel array in which pixels 102 including photoelectric conversion elements are arranged in an array, on which a low refractive index transparent layer 111 made of SiO2 or the like and a plurality of microlenses 103 are stacked. Inside the low refractive index transparent layer 111, a plurality of microspectroscopic elements 101 are embedded, each consisting of a microstructure with a constant thickness (length perpendicular to the two-dimensional pixel array) made of a material such as SiN having a refractive index higher than that of the transparent layer 111.

Description

[Technical Field]

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

[0002] Generally, in image sensors equipped with photoelectric conversion elements such as CCD (Charge Coupled Device) sensors and CMOS (Complementary Metal Oxide Semiconductor) sensors, it is necessary to separate the colors of the incident light in order to acquire color information of the object being imaged.

[0003] Figure 16 shows a cross-sectional view of a conventional color image sensor. In the conventional color image sensor 600, a photoelectric conversion element 602 is arranged on electrical wiring 601, and a color-reducing color filter 604 made of organic or inorganic multilayer film material is placed opposite each pixel containing the photoelectric conversion element 602. A microlens 605 is placed on top of the color filter 604.

[0004] When light enters through the microlens 605, the color filter 604 transmits only the desired wavelength band of light and absorbs or reflects the unwanted wavelength bands. By acquiring signals from three photoelectric conversion elements 602 corresponding to red (R), green (G), and blue (B) for each pixel, a color two-dimensional image can be generated.

[0005] However, with a typical color image sensor 600 as described above, there is a problem in that, when the incident light has an RGB ratio of 1:1:1, the total amount of light after passing through the color filter 604 is inevitably reduced to about 1 / 3. The remaining lost light is lost due to absorption or reflection and cannot reach the photoelectric conversion element 602. Therefore, the light utilization efficiency of the incident light is at most about 30%, and the sensitivity of the image sensor is severely limited. In recent years, with the miniaturization of pixels progressing, the amount of light received by each pixel has decreased, so there is a need to solve the above problem.

[0006] Therefore, it has been proposed to construct a color image sensor using spectroscopic elements such as miniature prisms or dichroic mirrors that can split incident light according to wavelength bands, instead of the color filter 604. In principle, this approach can greatly reduce the loss of incident light and significantly improve light utilization efficiency. However, in recent years, with the miniaturization of pixels progressing, it has become difficult to integrate such elements onto a photoelectric conversion element.

[0007] Therefore, in recent years, it has been proposed to construct a color image sensor using a spectroscopic element consisting of a microstructure that can be relatively easily integrated onto a photoelectric conversion element. Non-patent document 1 proposes a method to improve light utilization efficiency by using two types of microstructures that can separate incident light into two wavelength regions, thereby eliminating optical loss in color separation in principle.

[0008] Figure 17(a) shows a top view of a color image sensor using a conventional spectroscopic element, Figure 17(b) shows a cross-sectional view of the same element from XVIIb to XVIIb, and Figure 17(c) shows a cross-sectional view of the same element from XVIIc to XVIIc. As shown in the figures, the color image sensor 610 separates incident light into straight-traveling light and deflected light depending on the wavelength region, using fine beam structures 606-1 and 606-2, which are arranged corresponding to the pixels 602 instead of the color filter 604. This is because the phase delay effect experienced by the incident light within and around the fine beam structure differs significantly in one wavelength region, while being almost equal in the other wavelength region.

[0009] Therefore, by alternately arranging two types of fine beam structures 606-1 and 606-2 with different structural thicknesses in each row on a two-dimensional pixel array, four adjacent photoelectric conversion elements 602 can each receive light with different wavelength components. As a result, color information can be generated by matrix operations using the photoelectric conversion signals output from each photoelectric conversion element 602.

[0010] Furthermore, Non-Patent Literature 1 also proposes a color image sensor 620 that improves light utilization efficiency by arranging a step-shaped microstructure 607 on the pixel 602, as shown in Figure 18, which is capable of separating incident light into three wavelength regions. In addition to generating color information by matrix calculation as described above, this method allows the separated three wavelength regions of light to be incident on three adjacent photoelectric conversion elements 602, and it is thought that color information can be directly generated using the photoelectric conversion signals output from each photoelectric conversion element 602. [Prior art documents] [Non-patent literature]

[0011] [Non-Patent Document 1] Seiji Nishiwaki, Tatsuya Nakamura, Masao Hiramoto, Toshiya Fujii and Masa-aki Suzuki, “Efficient color splitters for high-pixel-density image sensors,” Nature Photonics, Vol. 7, March 2013, pp. 240-246 [Overview of the project] [Problems that the invention aims to solve]

[0012] However, the technology disclosed in Non-Patent Document 1 has practical problems.

[0013] First, in the method using microstructures 606-1 and 606-2 that separate incident light into two wavelength regions, the cost of the fabrication process increases because the structural heights of the two types of microstructures 606-1 and 606-2 are different. Furthermore, because microstructures 606-1 and 606-2 are beam-shaped structures with a long axis, the phase delay effect experienced by the light differs depending on the polarization direction of the incident light, resulting in a polarization-dependent color separation function. Additionally, since signal processing is performed from two sets of light intensity data separated into two wavelength regions to reconstruct RGB information, there are concerns about color reproducibility.

[0014] On the other hand, while the method using a step-shaped microstructure 607 that separates incident light into three wavelength regions theoretically yields a color image with high light utilization and good color reproduction, it is difficult to fabricate a microstructure 607 with ideal spectral characteristics. The disclosed step-shaped microstructure 607 requires multiple lithography and etching processes, as well as high-precision alignment techniques in the lithography process, which increases the fabrication cost. Furthermore, similar to the microstructures 606-1 and 606-2 that separate incident light into two wavelength regions, the shape of the microstructure 607 is a beam-type structure with a long axis, which presents the challenge of polarization dependence in its color separation function.

[0015] The present invention has been made in view of the above problems, and its objective is to provide a highly sensitive color image sensor and imaging device that integrates a microspectroscopic element, which can be easily manufactured, has low polarization dependence, and can separate incident light into three wavelength regions, with a two-dimensional pixel array. [Means for solving the problem]

[0016] To solve the above problems, one aspect of the present invention provides a color image sensor comprising: a two-dimensional pixel array in which a plurality of pixels including photoelectric conversion elements are arranged in a two-dimensional array on a substrate; a transparent layer formed on the two-dimensional pixel array; and a two-dimensional spectroscopic element array in which a plurality of spectroscopic elements are arranged in a two-dimensional array inside or on the transparent layer, wherein each of the spectroscopic elements includes a set of microstructures made of a material having a refractive index higher than that of the transparent layer, the set of microstructures consists of a plurality of microstructures having equal length in the direction perpendicular to the two-dimensional pixel array, different shapes in the direction horizontal to the two-dimensional pixel array, and arranged at intervals less than or equal to the wavelength of incident light, wherein at least a portion of the light incident on the spectroscopic element is separated into first to third deflected light with different propagation directions depending on the wavelength and emitted from the spectroscopic element, and incident on three pixels arranged continuously in one direction of the two-dimensional pixel array.

[0017] In another aspect of the present invention, the microstructure is characterized in that the structural bottom surface and top surface are columnar structures having a shape that is rotationally symmetrical four times with respect to the center as the axis of symmetry.

[0018] In another aspect of the present invention, the first to third deflected light is incident on the first to third photoelectric conversion elements of three adjacent consecutive pixels, respectively.

[0019] In another aspect of the present invention, when the incident light is white light, the light incident on the first photoelectric conversion element has a peak in light intensity in the blue wavelength range of 500 nm or less, the light incident on the second photoelectric conversion element has a peak in light intensity in the green wavelength range of 500 nm to 600 nm, and the light incident on the third photoelectric conversion element has a peak in light intensity in the red wavelength range of 600 nm or more.

[0020] In another aspect of the present invention, the shape of the set of microstructures is identical for all of the spectroscopic elements constituting the two-dimensional spectroscopic element array.

[0021] In another aspect of the present invention, the orientation of a pair of microstructures of adjacent spectroscopic elements arranged along a first direction of the two-dimensional spectroscopic element array is alternately reversed, and three adjacent consecutive pixels are arranged along the first direction, and of the three adjacent pixels along the first direction, the two outermost pixels are incident on any of the first to third deflected light from two adjacent spectroscopic elements along the first direction.

[0022] In another aspect of the present invention, the two-dimensional pixel array and the two-dimensional spectroscopic element array are further provided with a color filter array in which at least one of the following color filters is arranged in an array: a first color filter having a transmittance peak in the blue wavelength range of 500 nm or less, a second color filter having a transmittance peak in the green wavelength range of 500 nm to 600 nm, and a third color filter having a transmittance peak in the red wavelength range of 600 nm or more.

[0023] Another aspect of the present invention is an imaging device comprising a color image sensor according to an aspect of the present invention, an imaging optical system for forming an optical image on the imaging surface of the color image sensor, and a signal processing unit for processing electrical signals output by the color image sensor. [Effects of the Invention]

[0024] According to the present invention, by using a micro-spectroscopic element that can be easily manufactured, has low polarization dependence, and can separate incident light into three wavelength regions, a color image sensor and imaging device with high light utilization efficiency can be manufactured more easily than conventional methods. [Brief explanation of the drawing]

[0025] [Figure 1] This is a side view showing a schematic configuration of the imaging device of the present invention. [Figure 2] This figure schematically shows a portion of the cross-section of the pixel array and spectroscopic element array of an image sensor according to Embodiment 1 of the present invention. [Figure 3] (a) is a schematic top view of a part of the image sensor according to Embodiment 1 of the present invention, and (b) is a cross-sectional view thereof. [Figure 4] (a) is a top view of a columnar structure constituting a microspectroscopic element of an image sensor according to Embodiment 1 of the present invention, and (b) is a cross-sectional view thereof. [Figure 5] (a) is a cross-sectional view of an example of a microspectroscopic element of an image sensor according to Embodiment 1 of the present invention, and (b) is a diagram showing the phase delay distribution of each of the three wavelengths separated by the microspectroscopic element. [Figure 6] (a) is a top view of an example of a microspectroscopic element of an image sensor according to Embodiment 1 of the present invention, and (b) is a cross-sectional view thereof. [Figure 7] (a) is a diagram showing the wavelength dependence of the efficiency of propagation separated in three directions from the output end of a microspectroscopic element when parallel light with vertical polarization is incident on the upper surface of a columnar structure in an image sensor according to Embodiment 1 of the present invention, and (b) is a diagram showing the wavelength dependence of the efficiency of propagation separated in three directions from the output end of a microspectroscopic element when parallel light with transverse polarization is incident on the upper surface of a columnar structure. [Figure 8] Figures (a) to (h) show examples of structural patterns of the micro-spectroscopic elements of the image sensor according to Embodiment 1 of the present invention. [Figure 9] Figures (a) to (c) schematically represent the arrangement of pixels corresponding to the color components of an image sensor according to Embodiment 1 of the present invention. [Figure 10] Figures (a) to (c) schematically represent the arrangement of pixels corresponding to the color components of an image sensor according to Embodiment 1 of the present invention. [Figure 11] This shows a cross-sectional view of a schematic configuration of an image sensor, which is a modified example of Embodiment 1 of the present invention. [Figure 12] (a) is a schematic top view of a part of the image sensor according to Embodiment 2 of the present invention, and (b) is a cross-sectional view thereof. [Figure 13] This figure schematically shows the arrangement of pixels in an image sensor according to Embodiment 2 of the present invention. [Figure 14](a) is a schematic top view of a part of the image sensor according to Embodiment 3 of the present invention, and (b) is a cross-sectional view thereof. [Figure 15] (a) is a schematic top view of a part of the image sensor according to Embodiment 4 of the present invention, and (b) is a cross-sectional view thereof. [Figure 16] This is a cross-sectional view of a conventional color image sensor. [Figure 17] (a) is a top view of a conventional color image sensor using a spectroscopic element, (b) is a cross-sectional view of the same sensor from XVIIb to XVIIb, and (c) is a cross-sectional view of the same sensor from XVIIc to XVIIc. [Figure 18] This is a cross-sectional view of another color image sensor using a conventional spectroscopic element. [Modes for carrying out the invention]

[0026] The embodiments of the present invention will be described in detail below with reference to the drawings. However, it goes without saying that the following embodiments are merely examples, and the present invention is not limited to these embodiments.

[0027] Figure 1 is a side view showing a schematic configuration of the imaging device of the present invention. The image sensor 10 comprises a lens optical system 11, an image sensor 12 including a photoelectric conversion element such as a CCD or CMOS, and a signal processing unit 13 that processes the photoelectric conversion signal output from the image sensor 12 to generate an image signal.

[0028] When light such as natural light or illumination light enters object 1, the light transmitted / reflected / scattered by it, or the light emitted from object 1, forms an optical image on the image sensor 12 by the lens optical system 11. Generally, the lens optical system 11 is composed of a lens group consisting of multiple lenses arranged along the optical axis to correct various optical aberrations, but in Figure 1, the diagram is simplified and shown as a single lens. The signal processing unit 13 also has an image signal output that sends the generated image signal to the outside.

[0029] The imaging device 10 of the present invention may include known components such as an infrared light cut-off optical filter, an electronic shutter, a viewfinder, a power supply (battery), and a flashlight, but their descriptions are not particularly necessary for understanding the present invention and are therefore omitted. Furthermore, the above configuration is merely an example, and in the present invention, known components can be appropriately combined and used for the components other than the lens optical system 11, the image sensor 12, and the signal processing unit 13.

[0030] Before describing specific embodiments of the present invention, the general outline of the image sensor 12 in the embodiments of the present invention will be described.

[0031] The image sensor 12 according to an embodiment of the present invention comprises a pixel array in which a plurality of cells (pixels) 102 including photoelectric conversion elements are arranged in a two-dimensional manner, and a spectroscopic element array in which a plurality of minute spectroscopic elements 101 are arranged in a two-dimensional manner. Figure 2 is a schematic diagram showing a part of the cross-section of the pixel array and spectroscopic element array of the image sensor according to Embodiment 1 of the present invention. The spectroscopic element array is opposite the pixel array and is located on the side into which light from the lens optical system is incident. Each minute spectroscopic element 101 is composed of a plurality of columnar structures of constant thickness. For convenience, the minute spectroscopic elements 101 are represented by four columnar structures, but there are no restrictions on the number, spacing, or arrangement pattern, and various arrangement configurations are possible.

[0032] The visible light component in the light incident on the image sensor 12 is classified into a first color component, a second color component, and a third color component for each wavelength region. While the combinations of the first to third color components are generally those of the three primary colors red (R), green (G), and blue (B), they are not limited to these combinations as long as the light is divided into three wavelength regions.

[0033] In the embodiment of the present invention, the micro-spectroscopic element 101 utilizes the phase delay effect and its structural, dimensional, and wavelength dependence, as described later, to change the propagation direction of incident light according to the first to third color components described above, thereby spatially separating it on the pixel array. That is, in the embodiment of the present invention, at least a portion of the light incident on the image sensor is changed in propagation direction according to the color components by the micro-spectroscopic element 101 and incident on a plurality of pixels 102. Therefore, by appropriately setting the distance between the micro-spectroscopic element 101 and the pixels 102, it is possible to receive light separated into three wavelength ranges, each on a different pixel 102.

[0034] When light enters a pixel 102, the photoelectric conversion element outputs an electrical signal (photoelectric conversion signal) corresponding to the intensity of the incident light, so that a signal corresponding to the color component (color information) can be obtained directly or using signal calculations. Since the above-described miniature spectroscopic element 101 and multiple pixels 102 corresponding to the miniature spectroscopic element 101 are arranged in two dimensions, it is possible to obtain color information of the optical image of an object formed by the lens optical system 11.

[0035] In Embodiments 1 and 2, described later, by using a microlens array, almost all of the incident light passes through one of the tiny spectroscopic elements 101 constituting the spectroscopic element array, so that almost all of the incident light enters the pixel array separated into three wavelength ranges. Therefore, color information can be obtained directly from the photoelectric conversion signal or by simple calculations.

[0036] In Embodiments 3 and 4, described later, a portion of the incident light passes through the micro-spectroscopic elements 101 that constitute the spectroscopic element array, so that a portion of the incident light is incident on the pixel array in a state where it is separated into three wavelength ranges. Therefore, a portion of each pixel 102 outputs a photoelectric conversion signal corresponding to the sum of the light intensity of the light separated into the three wavelength ranges and the light that is not separated. Color information can be obtained from the output photoelectric conversion signal by using appropriate matrix operations, described later.

[0037] According to the image sensor 12 in the embodiment of the present invention, color information can be obtained by low-loss light separation into three colors using a micro-spectroscopic element 101 without using a color-reducing color filter. Therefore, compared to an image sensor using a color filter, the total amount of light reaching the pixel array can be increased, making it possible to improve imaging sensitivity. Furthermore, the micro-spectroscopic element 101 is composed of a structure of constant thickness that is easy to manufacture, and since there is no polarization dependence due to the symmetry of the top and bottom surfaces of the structure, it is possible to solve the problem of polarization dependence in the color separation function of the conventional technology disclosed in Non-Patent Document 1.

[0038] More specific embodiments of the present invention will be described below with reference to the drawings.

[0039] (Embodiment 1) The following describes the general configuration of the image sensor in this embodiment 1.

[0040] Figure 3(a) is a schematic top view of a part of the configuration of an image sensor according to Embodiment 1 of the present invention, and Figure 3(b) is a cross-sectional view thereof. In this Embodiment 1, the image sensor 100 has a two-dimensional pixel array in which pixels 102 including photoelectric conversion elements are arranged in an array, on which a low refractive index transparent layer 111 made of SiO2 or the like and a plurality of microlenses 103 are stacked. Inside the low refractive index transparent layer 111, a microspectroscopic element 101 is embedded, consisting of a plurality of microstructures of constant thickness (length perpendicular to the two-dimensional pixel array) made of a material such as SiN having a refractive index higher than that of the transparent layer 111. For convenience, in the following description, an xyz orthogonal coordinate system is set up in which the z-axis is the normal direction of the two-dimensional pixel array, the x-axis is the direction in which the three pixels 102 constituting the pixel unit 110 are aligned parallel to the two-dimensional pixel array, and the y-axis is the direction parallel to the two-dimensional pixel array and perpendicular to the x-axis.

[0041] As shown in the figure, the microlenses 103, the minute spectroscopic elements 101, and the pixels 102 are arranged in a grid pattern on the xy plane, with one minute spectroscopic element 101 positioned on the central axis of each microlens 103. If three adjacent pixels in the x-axis direction are considered as one pixel unit 110, then each adjacent microlens 103 in the x-axis direction corresponds one-to-one with each pixel unit 110, and the central axis of each microlens 103 passes approximately through the center of the central pixel 102 of the corresponding pixel unit. That is, one microlens 103 and one minute spectroscopic element 101 correspond to three adjacent pixels 102 in the x-axis direction, and if the above microlenses 103, minute spectroscopic elements 101, and pixel units 110 are considered as one image sensor unit, then that image sensor unit is arranged in a grid pattern on the xy plane.

[0042] In the above explanation, the case of a two-dimensional pixel array arranged in an orthogonal grid was described as an example, but the arrangement, shape, and size of the pixels 102 are not limited to the example shown in the figure, and any known arrangement, shape, and size may be used. Also, although omitted in Figures 3(a) and (b), a high refractive index uneven structure made of SiN or the like may be provided between the two-dimensional pixel array and the microstructure, which acts as an internal microlens and guides light from the miniature spectroscopic element 101 to the photoelectric conversion element in the pixel 102. The structures shown in Figures 3(a) and (b) can be fabricated using known semiconductor manufacturing techniques.

[0043] Although the image sensor 100 shown in Figures 3(a) and 3(b) has a back-illuminated structure that receives light from the opposite side of the wiring layer 112, this embodiment is not limited to such a structure and may have a front-illuminated structure that receives light from the side of the wiring layer 112.

[0044] The following describes the function of each component of the image sensor 100 in this embodiment.

[0045] The white light incident on the imaging element 100 is first condensed by the microlens array, and almost all the light passes through the micro-spectroscopic element 101 corresponding to each microlens 103. By each micro-spectroscopic element 101, the light is spatially separated into three wavelength regions in the xz plane, and is received by the three pixels 102 directly below each micro-spectroscopic element 101, respectively. In the example shown in Fig. 3(b), by each micro-spectroscopic element 101, the light of the first color component (R) propagates in the first direction (right), the light of the second color component (G) propagates in the second direction (straight), and the light of the third color component (B) propagates in the third direction (left). Therefore, the three pixels 102D R (right), D G (center), D B (left) respectively correspond to the detection of the color information of R, G, and B.

[0046] Note that the above is an example. Depending on the configuration of each micro-spectroscopic element 101, the combination of the color component and the propagation direction can be freely changed, and accordingly, the pixels 102D corresponding to each of RGB R , D G , D B are also changed.

[0047] When the light spatially separated into three wavelength regions in this way is received by the three pixels 102 respectively, photoelectric conversion is performed by the photoelectric conversion element in each pixel 102, and an image signal including color information is output.

[0048] Note that the widths w R , D G , D B in the x-axis direction of the three pixels 102D d1 , w d2 , w d3 may be the same or different. Also, accordingly, the width w lx in the x-axis direction and the width w ly in the y-axis direction of the microlens 103 may be the same or different. In the example of Fig. 3, the widths w R , D G , D B in the x-axis direction of the three pixels 102D d1 , w d2 , wd3 They are identical, and the microlens 103 is w lx and lol ly They are different.

[0049] Furthermore, a high refractive index uneven structure made of SiN or the like that acts as an internal microlens may be provided between the pixel unit 110 and the microspectroscopic element 101. However, since the microspectroscopic element 101, described later, can have a lens function depending on the phase delay distribution it forms, it is also possible to omit the internal microlens.

[0050] The following describes the microspectroscopic element in this embodiment.

[0051] The microspectroscopic element 101 in this embodiment 1 is composed of a plurality of fine columnar structures 121. Figure 4(a) is a top view of the columnar structure constituting the microspectroscopic element of the image sensor according to Embodiment 1 of the present invention, and Figure 4(b) is a cross-sectional view thereof. The columnar structure 121 is formed from a material such as SiN 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 constant.

[0052] Furthermore, the bottom and top surfaces of the columnar structure 121 are square. Due to the refractive index difference with the transparent layer 111, this columnar structure 121 functions as an optical waveguide that confines and propagates light within the structure. Therefore, when light is incident from the top side, the light propagates while being strongly confined within the columnar structure 121, and the effective refractive index n of the optical waveguide eff The phase delay effect determined by the above is then output from the bottom side. Specifically, when the phase of light propagating through the transparent layer 111 over a length equal to the thickness of the columnar structure 121 is used as the reference, the phase delay amount φ due to the columnar structure 121 is, if the wavelength of light in a vacuum is λ, φ=(n eff -n0) × 2πh / λ (1) It is represented by. Since this amount of phase delay varies depending on the wavelength λ of light, it is possible to give different amounts of phase delay according to the wavelength range (color component) for the light incident on the same columnar structure 121. Also, since the bottom and top surfaces of the columnar structure 121 are square, there is no change in the optical characteristics including the phase delay effect even when the polarization direction is changed. Further, n eff is known to be a function of the structural dimensions, and n0 < n eff < takes the value of n1. Therefore, in the examples shown in FIGS. 4(a) and (b), it is possible to set an arbitrary amount of phase delay by changing the width w of the columnar structure 121.

[0053] The cross-sectional view of FIG. 5(a) is an example of the micro-spectroscopic element 101 in the first embodiment, which is configured by arranging two of the above-described columnar structures 121-1 and 121-2 side by side in the x-axis direction. In the y-axis direction, a plurality of the above-described columnar structures 121-1 and 121-2 are arranged at intervals less than the wavelength.

[0054] As shown in FIG. 5(a), the widths w of the adjacent columnar structures 121-1 and 121-2 in the x-axis direction are different. Due to this difference in the width w, it is possible to give different phase delay distributions for each wavelength region to the light transmitted through the micro-spectroscopic element 101, and the optical wavefront can be changed. Since the propagation direction (deflection direction) of light is determined by this optical wavefront, it is possible to spatially separate the light transmitted through the micro-spectroscopic element 101 according to the wavelength range (color component). That is, the micro-spectroscopic element 101 in the first embodiment arranges a plurality of columnar structures 121, and by changing the dimension w in the plane orthogonal to the propagation direction of light of the adjacent columnar structures 121-1 and 121-2, different optical wavefronts are given according to the wavelength region of the incident light, and the color components are spatially separated.

[0055] For example, in the structure shown in Figure 5(a), different phase delay distributions can be given depending on the three wavelengths (e.g., wavelengths corresponding to RGB), as shown in Figure 5(b). In this example, the phase delay distribution for the wavelength corresponding to the first color component light (R) follows a straight line where the phase amount increases linearly from 0 to +2π, the phase delay distribution for the wavelength corresponding to the second color component light (G) has no spatial change, and the phase delay distribution for the wavelength corresponding to the third color component light (B) follows a straight line where the phase amount decreases linearly from 0 to -2π. In this case, as shown in Figure 5(a), the light transmitted through the micro-spectroscopic element 101 can efficiently propagate in the first direction (right) for the first color component light (R), in the second direction (straight) for the second color component light (G), and in the third direction (left) for the third color component light (B).

[0056] The above explanation is merely an example, and the combination of color components and deflection directions can be freely changed depending on the dimensions of each columnar structure 121. For example, the light of the first color component (R) can efficiently propagate in the second direction (straight), the light of the second color component (G) in the first direction (right), and the light of the third color component (B) in the third direction (left).

[0057] A more detailed example of the microspectroscopic element 101 in this embodiment will be described.

[0058] Figure 6(a) is a top view of an example of a microspectroscopic element of an image sensor according to Embodiment 1 of the present invention, and Figure 6(b) is a cross-sectional view thereof. Two columnar structures 121-1 and 121-2 with different widths w1 and w2 and a constant thickness (length perpendicular to the 2D pixel array) are arranged in the x-axis direction, and three identical columnar structures 121-1 and 121-2 are arranged in the y-axis direction, and these constitute one microspectroscopic element 101. The material constituting the columnar structures 121-1 and 121-2 is assumed to be SiN (n1=2.03), and the material constituting the transparent layer is assumed to be SiO2 (n0=1.45), and the bottom and top surfaces are shown as square. Furthermore, the thickness h of all columnar structures 121-1 and 121-2 was set to 1200 nm, the width w1 of columnar structure 121-1 on the left side of the pattern was set to 145 nm, and the width w2 of columnar structure 121-2 on the right side of the pattern was set to 340 nm. The spacing p between columnar structures 121-1 and 121-2 in the x and y axes was set to 450 nm.

[0059] Figures 7(a) and 7(b) show the wavelength dependence (calculation results based on exact coupled wave theory) of the efficiency (ratio of light intensity in each propagation direction to incident light intensity) of propagation in three directions (R, G, and B directions in Figure 6(b)) from the exit end of the microspectroscopic element 101 when parallel light is incident from the upper surface of the columnar structures 121-1 and 121-2 in the above-described structure. Figure 7(a) shows the results when light with vertical polarization in Figure 6(a) is incident, and Figure 7(b) shows the results when light with horizontal polarization in Figure 6(a) is incident. In the calculation, it was assumed that the above-described microspectroscopic elements 101 were arranged at intervals of P (P=3p) in the x and y axes, but it was confirmed that there is almost no difference from the optical function of a single microspectroscopic element 101. Furthermore, the deflection angles θ in each of the three directions are also shown. R θ G θ B This is based on the diffraction of light, where R:sinθ R =λ / P, G:θ G =0 (straight line), B: sinθ B Let =λ / P.

[0060] Furthermore, the characteristics shown in Figures 7(a) and (b) correspond to the spectral sensitivity characteristics of color filters in conventional imaging devices. The results shown in Figures 7(a) and (b) indicate that the efficiency in the first direction (R) peaks in the red wavelength range above 600 nm, the efficiency in the second direction (G) peaks in the green wavelength range of 500-600 nm, and the efficiency in the third direction (B) peaks in the blue wavelength range below 500 nm. In addition, it exhibits good spectral performance of 40-60%, and there is no significant polarization dependence on the characteristics. Moreover, the sum of curves R, G, and B, i.e., the total transmittance, is over 95%, indicating almost no light loss due to scattering or reflection.

[0061] The above results demonstrate that highly efficient spatial separation of color components is possible by using the microspectroscopic element 101 in this embodiment 1. Furthermore, in the above example, the size of a single microspectroscopic element 101 is 1.35 μm square, which is equivalent to the minimum pixel size of a typical CCD and CMOS sensor. Therefore, it is possible to form a microspectroscopic element 101 corresponding to a pixel unit 110 with the minimum pixel size. It is also possible to form microspectroscopic elements 101 of different sizes by changing the size, number, and arrangement pattern of the columnar structures 121.

[0062] By appropriately designing the material, number, shape, size, and arrangement pattern of the columnar structures 121 that constitute the microspectroscopic element 101, it is possible to provide desired spectral characteristics. As a result, as described above, it becomes possible to isolate and incident only light in the desired wavelength range onto each photoelectric conversion element, and signals corresponding to the color components can be obtained from the photoelectric conversion signals output from each photoelectric conversion element.

[0063] Furthermore, as mentioned above, since there is almost no light loss due to the micro-spectroscopic elements 101, the total amount of light reaching the pixel array can be dramatically increased compared to image sensors using conventional color filters, thereby improving imaging sensitivity. Even if the spectral performance of each micro-spectroscopic element 101 differs somewhat from the ideal performance described above, it is possible to obtain good color information by correcting and calculating the acquired signal according to the degree of the performance difference.

[0064] Furthermore, in arranging each of the columnar structures 121 described above, it is desirable to arrange them at intervals smaller than the wavelength of light in order to prevent the generation of unwanted diffracted light caused by the periodic structure.

[0065] The above example described the case where the base and top surfaces of the columnar structure are square, but the structure is not limited to this shape. That is, if the shape of the surface is rotationally symmetric four times with respect to the axis passing through the center of the base and top surfaces, there will be no dependence of the spectral function on polarization, and the operation as an optical waveguide that produces a phase delay effect will not be lost. Therefore, it is desirable to adopt a columnar structure with a surface that is rotationally symmetric four times, such as a square, hollow square, circle, hollow circle, or cross shape, as shown in Figures 8(a) to (h).

[0066] Furthermore, in order for the light spatial distributions on the pixel unit 110 to be sufficiently separated from each other after the separation of color components by the microspectroscopic element 101, it is preferable that the distance between the output end of the microspectroscopic element 101 and the photoelectric conversion element of the pixel 102 be 1 μm or more. On the other hand, in order to thin the image sensor 100 and save on material costs and process time, it is preferable that the distance between the output end of the microspectroscopic element 101 and the photoelectric conversion element of the pixel 102 be as short as possible.

[0067] Furthermore, in this case, since the optical spatial distributions on the pixel unit 110 need to be clearly separated from each other according to their color components over a short propagation distance, it is preferable to tilt the wavefront of the light significantly using the micro-spectroscopic element 101 to increase the deflection (bending) angle. To increase the deflection angle, it is suitable for the phase delay distribution in each wavelength range formed by the micro-spectroscopic element 101 to change from 0 to 2π. Therefore, it is preferable that the variable range of the phase delay amount by the columnar structure 121 in each wavelength range is 2π or more. Accordingly, from equation (1), the desired center wavelength in the longest wavelength range of the wavelength ranges to be separated is λ r Therefore, the thickness h of the columnar structure 121 is h = λ r It is desirable to set it in the vicinity of / (n1-n0).

[0068] The miniature spectroscopic element 101 having the spectroscopic function described above can be fabricated by performing thin film deposition and patterning using known semiconductor manufacturing techniques. Since the miniature spectroscopic element 101 of this embodiment 1 is composed of multiple columnar structures 121 of constant thickness, it can be manufactured inexpensively and easily compared to the stepped structure disclosed in Non-Patent Document 1, etc.

[0069] The arrangement of the minute optical elements and pixels in the image sensor of this embodiment will be described below.

[0070] In the example shown in Figure 3, rows of microspectroscopic elements 101 arranged along the x-axis are repeatedly arranged along the y-axis without shifting in the x-axis direction, resulting in a continuous pattern of microspectroscopic elements 101 along the y-axis. In this case, in the x-axis direction, there are three pixels 102D corresponding to the color component directly beneath each microspectroscopic element 101. B , D G , D R They are arranged from left to right in this order, and this arrangement is repeated.

[0071] Furthermore, similarly for pixel 102, the rows of pixels 102 arranged along the x-axis are repeated along the y-axis without shifting along the x-axis, resulting in three pixels 102D along the y-axis. B , D G , D R They are arranged in a continuous sequence.

[0072] Figures 9(a) to (c) schematically represent the arrangement of pixels corresponding to the color components of an image sensor according to Embodiment 1 of the present invention. Three adjacent pixels 102D in the x-axis direction B , D G , D R If we consider this as one color pixel unit U, then both the color pixel unit U1 shown in Figure 9(a), and the color pixel unit U2 which is shifted by one pixel in the x-axis direction relative to color pixel unit U1, will always contain exactly one pixel each corresponding to R, G, and B. In other words, by acquiring color information while shifting the color pixel unit U by one pixel at a time in the xy plane, it is possible to obtain information for approximately the number of pixels for all three RGB colors. This means that the resolution of the image sensor can be increased to the extent of the number of pixels (equivalent to the so-called Bayer arrangement). Therefore, in addition to being highly sensitive, the image sensor of this embodiment 1 can generate color information with high resolution at the size of a single pixel.

[0073] The arrangement of the micro-optical elements and pixels that achieve the single-pixel size resolution described above is not limited to Figure 9(a) and can be changed in various ways. Figures 9(b) and 9(c) show another example, in which rows of micro-spectroscopic elements 101 and color pixel units U configured along the x-axis are sequentially arranged along the y-axis, shifting by one pixel size in the x-axis direction in Figure 9(b) and two pixel sizes in Figure 9(c). With such an arrangement, color information can be generated with a single-pixel size resolution, similar to Figure 9(a).

[0074] Figures 10(a) to (c) show an example of a different arrangement from Figures 9(a) to (c), with 3 pixels D per row. B , DG , D R The order of these elements is reversed, and the shift in the x-axis direction is the same as in Figures 9(a) to (c) above. In this case as well, color information can be generated with a resolution of a single pixel size, similar to Figure 9(a). Note that 3 pixels D B , D G , D R To reverse the order, one can use a pattern in which the columnar structures 121-1 and 121-2 of the aforementioned microspectroscopic element 101 are flipped horizontally along the x-axis.

[0075] In the pixel arrangement shown in Figures 9(a)-(c) and 10(a)-(c) above, incident light propagates through the function of each minute spectroscopic element 101, with the first color component (R) moving in the first direction (right), the second color component (G) moving in the second direction (straight), and the third color component (B) moving in the third direction (left), with the three pixels 102D directly below each minute spectroscopic element 101. R (right), D G (Center), D B (Left) This is the case when it is assumed that each corresponds to the detection of R, G, and B color information. As mentioned above, depending on the configuration of the microspectroscopic element 101, the pixel 102 directly below the microspectroscopic element 101 will correspond to one of the three RGB colors, but basically only the order within the color pixel unit U is changed. Even in such cases, if the arrangement is set according to the arrangement rules of the color pixel unit U shown in Figures 9 and 10, color information can be generated with a resolution of the size of a single pixel in the same way.

[0076] The above description concerns the image sensor 100 when only the micro-spectroscopic element 101 is used. Next, we will describe a modified example when a color-reducing color filter is used in combination.

[0077] Figure 11 shows a cross-sectional view of a schematic configuration of an image sensor, which is a modified example of Embodiment 1 of the present invention. The difference from Figure 3 is that a color filter 104 corresponding to the color of each pixel 102 is placed above the pixel 102 corresponding to the color component; otherwise, it is the same. In this configuration, light utilization efficiency and color reproduction are improved compared to the conventional configuration with only color filters.

[0078] For example, as shown in Figure 7, the spectral efficiency of the microspectroscopic element 101 for RGB is assumed to be 40-60%. The transmittance (spectral efficiency) of the RGB color filters 104 in their corresponding wavelength ranges is assumed to be 90% each. The incident light is assumed to have an intensity ratio of 1:1:1 for RGB. In this case, with the configuration using both the microspectroscopic element 101 and the color filters 104, the light passes through both and enters the pixels, resulting in a total light intensity of 36-54% reaching the three RGB pixels 102. Furthermore, the spectral performance of the microspectroscopic element 101 and the color filters 104 are multiplied, and unwanted color components are eliminated before the light enters each pixel 102, significantly improving color reproducibility. On the other hand, with only the color filters 104, the total light intensity reaching the three pixels 102 is 30%, and the color reproducibility is worse compared to the combined configuration. Therefore, by using a configuration that combines the micro-spectroscopic element 101 and the color filter 104, it is possible to improve color reproducibility while achieving a 1.2 to 1.8 times improvement in sensitivity compared to a conventional configuration using only a color filter. Although the light utilization efficiency is lower compared to a configuration using only the micro-spectroscopic element 101, the color reproducibility is significantly improved. Thus, this modified embodiment 1 can be said to be a configuration that strikes a good balance between light utilization efficiency, i.e., sensitivity, and color reproducibility.

[0079] (Embodiment 2) Next, an image sensor according to Embodiment 2 of the present invention will be described.

[0080] Figure 12(a) is a schematic top view of a part of the configuration of an image sensor according to Embodiment 2 of the present invention, and Figure 12(b) is a cross-sectional view thereof. As shown in Figures 12(a) and (b), the image sensor 300 of Embodiment 2 and the imaging device using it differ from Embodiment 1 in that the orientation of the structural patterns of the plurality of minute spectroscopic elements 101 arranged along the x-axis is alternately reversed.

[0081] Furthermore, the rows of the microspectroscopic elements 101 and color pixel units U, which are configured along the x-axis, are sequentially arranged along the y-axis while shifting by 2 pixel sizes along the x-axis. As a result, the orientation of the structural pattern of the microspectroscopic elements 101 alternately reverses along the y-axis. In addition, of the three pixels 102 adjacent to each other along the x-axis that receive light spectrally dispersed by one microspectroscopic element 101, the two outermost pixels 102 also receive light spectrally dispersed by the other two adjacent microspectroscopic elements 101. Note that the other components of this embodiment 2 are the same as those of embodiment 1. The following description will focus on the differences from embodiment 1, and redundant points will be omitted.

[0082] As shown in Figure 12(b), the orientation of the structural pattern of the microspectroscopic element 101 alternately reverses along the x-axis, so the combination of color component and deflection direction alternately reverses, and consequently the pixels 102 corresponding to the color component directly below each microspectroscopic element 101 are D from left to right. R , D G , D B , D G , D R , D G , D B ...and so it is in this order. Directly below each microspectroscopic element 101 is a pixel 102D G It is arranged with 102 pixels on either side. R Or D B It also receives light spectrally separated by two adjacent microspectroscopic elements 101.

[0083] White light incident on the image sensor 300 is first focused by a microlens array, and almost all of the light passes through a miniature spectroscopic element 101 corresponding to each microlens 103. Each miniature spectroscopic element 101 spatially separates the light into three wavelength ranges in the xz plane, and these are received by three pixels 102 corresponding to each miniature spectroscopic element 101. At this time, the pixel 102 (D) directly below the miniature spectroscopic element 101 G ) pixels 102 (D on both sides R , D B ) also receives light propagating from two adjacent microspectroscopic elements 101, but due to the inversion of the structural pattern, it receives light in the same wavelength range.

[0084] The above is merely an example, and the combination of color components and propagation direction can be freely changed depending on the configuration of each minute spectroscopic element 101, and the pixels 102 corresponding to each of RGB will also be changed accordingly. When light spatially separated into three wavelength ranges is received by each of the three pixels 102, photoelectric conversion is performed by the photoelectric conversion element within each pixel 102, and the resulting image signal containing color information is output.

[0085] Figure 13 schematically shows the pixel arrangement of an image sensor according to Embodiment 2 of the present invention. R , two D G , and one D B Four pixels 102 including are considered as one color pixel unit U. In this case, even if only one pixel is shifted in the x-axis or y-axis direction relative to the color pixel unit U1 shown in the figure, one D R , two D G , and one D B A color pixel unit U2 can be configured that includes the above. That is, by shifting the color pixel unit U one pixel at a time in the xy plane and acquiring color information, it is possible to obtain information for approximately the number of pixels in the RGB three colors. This means that the resolution of the image sensor can be increased to the extent of the number of pixels. Therefore, in addition to being highly sensitive, the image sensor 300 of this embodiment 2 can generate color information with high resolution at the size of a single pixel.

[0086] Based on the above, the configuration of this second embodiment can achieve the same functions as that of the first embodiment. Furthermore, this second embodiment is the same as the first embodiment except for the differences from the first embodiment, and the common components have the same effects as those described in the first embodiment, and the same modifications are possible.

[0087] (Embodiment 3) Next, an image sensor according to Embodiment 3 of the present invention will be described.

[0088] Figure 14(a) is a schematic top view of a part of the configuration of the image sensor according to Embodiment 3 of the present invention, and Figure 14(b) is a cross-sectional view thereof. As shown in Figures 14(a) and (b), the image sensor 400 and imaging device of Embodiment 3 differ from those of Embodiment 1 in that the microlenses are arranged to correspond one-to-one with each pixel. Another difference is that matrix operations using photoelectric conversion signals from each pixel 102 are used to acquire color information. Other components are the same as those of Embodiment 1. The following explanation will focus on the differences from Embodiment 1, and redundant points will be omitted.

[0089] As shown in Figure 14(b), the microlenses 103 are arranged in a one-to-one correspondence with each pixel 102. Consequently, of the white light incident on the image sensor 400, only the light focused by the microlens 103 located directly above each microspectroscopic element 101 is incident on the microspectroscopic element 101 and color-separated, while the remaining light is incident directly on the pixels directly below each microlens via each microlens 103.

[0090] Here, if we represent the intensity of white light incident on a single microlens 103 as W, and the intensities of the three RGB colors that make up the white light as R, G, and B respectively, then through the three microlenses 103, the pixels 102D R , D G , D BThe light incident thereon is light with intensities represented by W+R, G, and W+B respectively. Note that the above is an example, and depending on the configuration of each micro-spectroscopic element 101, the combination of color components and propagation directions can be freely changed. Accordingly, for pixel 102D R D G D B the composition of the color components incident thereon is also changed. In the following description, for pixel 102D R D G D B D

[0091] The light with intensities of W+R, G, and W+B incident on each pixel 102 is photoelectrically converted by a photoelectric conversion element and output as a photoelectric conversion signal. Here, the photoelectric conversion signals corresponding to the light intensities of the three RGB colors and white light W are S R S G S B S W Let the photoelectric conversion signals output by each pixel 102 on which light with intensities of W+R, G, and W+B is incident be S W+R S G S W+B respectively. Note that S W is represented by S W =S R +S G +S B and S W+R S W+B can be represented by the relational expressions of S W+R =S W +S R and S W+B =S W +S B respectively. Also, since the light incident on pixel 102D G is the G component spectrally separated by micro-spectroscopic element 101, S G is output as it is.

[0092] From the above, S R S GS B The following S W+R S G S W+B It can be obtained using matrix operations.

[0093]

number

[0094] Therefore, each pixel D R , D G , D B Three photoelectric conversion signals S are output from there. W+R S G S W+B The signal calculation using this method provides the intensity information of the three color components, S R S G S B It is possible to find this.

[0095] Based on the above, the same functions as in Embodiment 1 can be achieved in the configuration of Embodiment 3. Embodiment 3 is the same as Embodiment 1 except for the differences from Embodiment 1, and the common components have the same effects as those described in Embodiment 1, and the same modifications are possible. In the modified example using a color filter, it is desirable to place the color filter for the corresponding color component only on the pixel 102 directly below the micro-spectroscopic element 101.

[0096] (Embodiment 4) Next, an image sensor according to Embodiment 4 of the present invention will be described.

[0097] Figure 15(a) is a schematic top view of a part of the image sensor according to Embodiment 4 of the present invention, and Figure 15(b) is a cross-sectional view thereof. As shown in Figures 15(a) and (b), the image sensor 500 of Embodiment 4 and the imaging device using it differ from Embodiment 2 in that the microlenses 103 are arranged in a one-to-one correspondence with each pixel 102. Another difference is that matrix operations using photoelectric conversion signals from each pixel 102 are used to acquire color information. Other components are the same as those of Embodiment 2. The following explanation will focus on the differences from Embodiment 2, and redundant points will be omitted.

[0098] As shown in Figure 15(b), the microlenses 103 are arranged in a one-to-one correspondence with each pixel 102. Consequently, of the white light incident on the image sensor 500, the only light that is incident on each minute spectroscopic element 101 and color-separated is the light focused by the microlens 103 located directly above the minute spectroscopic element 101, while the remaining light is incident directly on the pixels 102 directly below each microlens 103 via each microlens 103.

[0099] Here, as in the description of Embodiment 3, if we represent the intensity of white light incident on a single microlens 103 as W, and the intensities of the three RGB colors constituting the white light as R, G, and B respectively, then through the five microlenses 103, the pixels 102D R , D G , D B The light incident on each pixel 102D has intensities represented by W+2R, G, and W+2B, respectively. Note that the above is just one example; the combination of color components and propagation direction can be freely changed depending on the configuration of each minute spectroscopic element 101, and accordingly, the pixel 102D R , D G , D B The composition of the color components incident on each of them is also changed. In the following explanation, pixel 102D R , D G , D BThe following describes the acquisition of color information by matrix operations when light of intensities W+2R, G, and W+2B are incident on the elements, respectively. It goes without saying that the numerical values ​​of the matrix operators can be changed in various ways depending on the configuration and spectral performance of the microspectroscopic element 101.

[0100] The light of intensities W+2R, G, and W+2B incident on each pixel 102 is photoelectrically converted by a photoelectric conversion element and output as a photoelectric conversion signal. Here, similar to the description in Embodiment 3, the photoelectric conversion signal corresponding to the light intensity of the three RGB colors and white light W is S R S G S B S W Let S be the photoelectric conversion signal output by each pixel 102 that is incident on light of intensity W+2R, G, and W+2B, respectively. W+2R S G S W+2B Let's assume that S W is S W =S R +S G +S B It is represented as S W+2R S W+2B These are S W+2R =S W +2S R S W+2B =S W +2S B It can be expressed by the following relationship: Furthermore, pixel 102D G The light incident on is the G component spectrally separated by the micro-spectroscopic element 101, therefore S G This will be output as is.

[0101] Therefore, S R S G S B The following S W+2R S G S W+2B It can be obtained using matrix operations.

[0102]

number

[0103] Therefore, each pixel D R , D G , D B Three photoelectric conversion signals S are output from there. W+2R S G S W+2B The signal calculation using this method provides the intensity information of the three color components, S R S G S B It is possible to find this.

[0104] Based on the above, the configuration of this embodiment 4 can achieve the same functions as in embodiment 2. This embodiment 4 is the same as embodiment 2 except for the differences from embodiment 2, and the common components have the same effects as those described in embodiment 2, and the same modifications are possible. In the modified example using a color filter, it is desirable to place the color filter for the corresponding color component only on the pixel directly below the micro-spectroscopic element 101.

[0105] The embodiments 1 to 4 described above are merely preferred examples of the present invention, and the present invention is not limited thereto; various modifications are possible.

[0106] In Embodiments 1 to 4 described above, examples were shown in which SiN was assumed as the material for the microspectroscopic element 101, but the present invention is not limited thereto. For example, when the image sensor of the present invention is used in the visible light region with a wavelength in the range of 380 to 800 nm, materials such as SiN, SiC, TiO2, and GaN are suitable for the microspectroscopic element because they have a high refractive index and low absorption loss. For near-infrared light with a wavelength in the range of 800 to 1000 nm, materials such as Si, SiC, SiN, TiO2, GaAs, and GaN are suitable as materials with low loss for this light. Furthermore, in the near-infrared region of long wavelengths (such as communication wavelengths of 1.3 μm and 1.55 μm), in addition to the materials mentioned above, InP and the like can be used. Furthermore, when forming a microspectroscopic element by bonding or coating, materials such as polyimides such as fluorinated polyimides, BCB (benzocyclobutene), photocurable resins, UV epoxy resins, acrylic resins such as PMMA, and polymers such as resists in general can be used.

[0107] Similarly, while Embodiments 1 to 4 described above show examples in which SiO2 is assumed as the material for the transparent layer 111, the present invention is not limited thereto. Any material with a refractive index lower than that of the microspectroscopic element material and with low loss with respect to the wavelength of incident light may be used, such as general glass material, SiO2, or an air layer.

[0108] In Embodiments 1 to 4 described above, the case in which the micro-spectroscopic element 101 uses light of the three primary colors red, green, and blue as the corresponding three wavelength ranges was explained. However, at least one of the three wavelength ranges may be light of a wavelength other than the three primary colors (for example, infrared light or ultraviolet light).

[0109] 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. [Explanation of symbols]

[0110] 1 object 10 Imaging device 11 Lens Optics 12 Image sensor 13 Signal Processing Unit 100, 200, 300, 400, 500, 600, 610, 620 image sensors 101 Microscopic Spectroscopic Element 102 pixels 103 Microlens 104 color filters 111 Transparent layer 112 Wiring layer 121 Columnar structure 601 Wiring layer 602 pixels 603 Transparent layer 604 color filters 605 Microlens 606, 607 Microstructure

Claims

1. A pixel array in which multiple pixels, including photoelectric conversion elements, are arranged on a substrate, A transparent layer arranged on the aforementioned pixel array, Multiple spectroscopic elements provided inside the transparent layer, A lens placed on the transparent layer and Equipped with, The aforementioned pixel array has a series of pixel units, each consisting of multiple pixels, arranged in a sequence. The lens is provided for each pixel unit, and its width in the direction horizontal to the pixel array plane is the same as the width of the pixel unit. One spectroscopic element is arranged for each lens. An image sensor characterized by the following features.

2. The image sensor according to claim 1, characterized in that the pixel unit has three pixels corresponding to RGB arranged in a row in a direction horizontal to the pixel array surface.

3. The image sensor according to claim 1, characterized in that each of the spectroscopic elements is composed of a plurality of microstructures formed of a material with a refractive index different from that of the transparent layer.

4. The image sensor according to claim 1, characterized in that each of the pixel units has a center of a plane horizontal to the pixel array surface located on the central axis of the lens.

Images