Optical element, photodetection device, and electronic apparatus

Abstract

An optical element according to an embodiment of the present disclosure comprises: a substrate; and an optical layer that has a plurality of first structures and is provided in a manner of being layered on the substrate. The optical layer has a first region and a second region. The center position of the first region is different from the center position of the second region. The optical layer can condense first polarized light incident on the first region, and can condense second polarized light which is different from the first polarized light and is incident on the second region.

Description

Optical element, photodetector, and electronic device

[0001] The present disclosure relates to optical elements, photodetection devices, and electronic devices.

[0002] A solid-state imaging device has been proposed that includes a polarization control element that includes a plurality of meta-atoms and focuses the polarized components of incident light toward the center of a pixel (Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2023-24079

[0004] It is desirable for an optical element to be able to efficiently collect incident light.

[0005] It is desirable to provide an optical element that can efficiently focus light.

[0006] An optical element according to an embodiment of the present disclosure includes a substrate and an optical layer having a plurality of first structures and stacked on the substrate. The optical layer includes a first region and a second region. The center position of the first region is different from the center position of the second region. The optical layer is capable of collecting first polarized light incident on the first region and second polarized light different from the first polarized light incident on the second region. A photodetector according to an embodiment of the present disclosure includes a semiconductor layer, a first photoelectric conversion region and a second photoelectric conversion region provided in the semiconductor layer, and an optical layer provided above the semiconductor layer and having a plurality of first structures. The optical layer includes a first region corresponding to the first photoelectric conversion region and a second region corresponding to the second photoelectric conversion region. The center position of the first region is different from the center position of the second region. The optical layer guides the first polarized light incident on the first region to the first photoelectric conversion region and guides the second polarized light different from the first polarized light incident on the second region to the second photoelectric conversion region. According to an embodiment of the present disclosure, an electronic device includes an optical system and a photodetector that receives light transmitted through the optical system. The photodetector includes a semiconductor layer, a first photoelectric conversion region and a second photoelectric conversion region provided in the semiconductor layer, and an optical layer provided above the semiconductor layer and having a plurality of first structures. The optical layer includes a first region corresponding to the first photoelectric conversion region and a second region corresponding to the second photoelectric conversion region. The center position of the first region is different from the center position of the second region. The optical layer guides first polarized light incident on the first region to the first photoelectric conversion region and guides second polarized light, different from the first polarized light, incident on the second region to the second photoelectric conversion region.

[0007] FIG. 1 is a block diagram showing an example of a schematic configuration of an imaging device which is an example of a photodetector according to a first embodiment of the present disclosure. FIG. 2 is a diagram showing an example of a pixel unit of the imaging device according to the first embodiment of the present disclosure. FIG. 3A is a diagram for explaining an example of a planar configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 3B is a diagram for explaining an example of a planar configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 4 is a diagram showing an example of a circuit configuration of a pixel of the imaging device according to the first embodiment of the present disclosure. FIG. 5 is a diagram showing an example of a cross-sectional configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 6 is a diagram for explaining an example of a configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 7 is a diagram for explaining an example of a configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 8 is a diagram showing an example of a configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 9 is a diagram showing an example of a configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 10 is a diagram showing an example of a configuration of an imaging device according to a comparative example of the present disclosure. FIG. 11 is a diagram showing an example of a configuration of the imaging device according to the comparative example of the present disclosure. FIG. 12 is a diagram showing another example of a configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 13 is a diagram illustrating another example configuration of an imaging device according to the first embodiment of the present disclosure. FIG. 14 is a diagram illustrating an example configuration of an imaging device according to the first embodiment of the present disclosure. FIG. 15 is a diagram illustrating an example configuration of a structure of an imaging device according to Modification 1 of the present disclosure. FIG. 16 is a diagram illustrating another example configuration of a structure of an imaging device according to Modification 1 of the present disclosure. FIG. 17 is a diagram illustrating another example configuration of a structure of an imaging device according to Modification 1 of the present disclosure. FIG. 18 is a diagram illustrating an example configuration of an imaging device according to Modification 2 of the present disclosure. FIG. 19 is a diagram illustrating an example configuration of an imaging device according to Modification 3 of the present disclosure. FIG. 20A is a diagram illustrating an example configuration of an imaging device according to Modification 3 of the present disclosure. FIG. 20B is a diagram illustrating an example configuration of an imaging device according to Modification 3 of the present disclosure. FIG. 21 is a diagram illustrating an example configuration of an imaging device according to Modification 4 of the present disclosure. FIG. 22 is a diagram illustrating an example configuration of an imaging device according to Modification 4 of the present disclosure. FIG. 23 is a diagram illustrating an example configuration of an imaging device according to Modification 5 of the present disclosure.FIG. 24 is a diagram for describing an example configuration of an imaging device according to Modification 5 of the present disclosure. FIG. 25 is a diagram for describing an example configuration of an imaging device according to Modification 6 of the present disclosure. FIG. 26 is a diagram for describing an example configuration of an imaging device according to Modification 7 of the present disclosure. FIG. 27 is a diagram for describing an example configuration of an imaging device according to Modification 7 of the present disclosure. FIG. 28 is a diagram for describing an example configuration of an imaging device according to Modification 7 of the present disclosure. FIG. 29 is a diagram for describing another example configuration of an imaging device according to Modification 7 of the present disclosure. FIG. 30 is a diagram for describing another example configuration of an imaging device according to Modification 7 of the present disclosure. FIG. 31A is a diagram for describing an example configuration of an imaging device according to Modification 8 of the present disclosure. FIG. 31B is a diagram for describing an example configuration of an imaging device according to Modification 8 of the present disclosure. FIG. 32 is a diagram for describing an example configuration of an imaging device according to Modification 8 of the present disclosure. FIG. 33 is a diagram for describing an example configuration of an imaging device according to Modification 9 of the present disclosure. FIG. 34 is a diagram for describing an example configuration of an imaging device according to Modification 9 of the present disclosure. FIG. 35A is a diagram for describing a configuration example of an imaging device according to Modification 10 of the present disclosure. FIG. 35B is a diagram for describing a configuration example of an imaging device according to Modification 10 of the present disclosure. FIG. 36 is a diagram for describing a configuration example of an optical element according to a second embodiment of the present disclosure. FIG. 37 is a diagram for describing a configuration example of an optical element according to the second embodiment of the present disclosure. FIG. 38 is a diagram for describing another configuration example of an optical element according to the second embodiment of the present disclosure. FIG. 39 is a block diagram showing a configuration example of an electronic device having an imaging device. FIG. 40 is a block diagram showing an example of a schematic configuration of a vehicle control system. FIG. 41 is an explanatory diagram showing an example of installation positions of an outside-vehicle information detection unit and an imaging unit. FIG. 42 is a diagram showing an example of a schematic configuration of an endoscopic surgery system. FIG. 43 is a block diagram showing an example of the functional configuration of a camera head and a CCU.

[0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order: 1. First embodiment 2. Second embodiment 3. Application example 4. Application example

[0009] 1. First Embodiment Fig. 1 is a block diagram showing an example of a schematic configuration of an imaging device which is an example of a photodetection device according to a first embodiment of the present disclosure. Fig. 2 is a diagram showing an example of a pixel unit of the imaging device according to the first embodiment. The photodetection device is a device capable of detecting incident light. The imaging device 1 which is an example of a photodetection device has a plurality of pixels P including photoelectric conversion units (photoelectric conversion regions) and is configured to photoelectrically convert incident light to generate a signal.

[0010] The imaging device 1 receives light that has passed through an optical system (not shown) including, for example, an optical lens, and generates a signal. The imaging device 1 is configured, for example, using a semiconductor substrate (e.g., a Si (silicon) substrate, an SOI (silicon on insulator) substrate, etc.) on which a photoelectric conversion unit of each pixel P is provided. The imaging device 1 may have a structure (a stacked structure) configured by stacking multiple semiconductor layers.

[0011] The photoelectric conversion unit (i.e., photoelectric conversion region) of the pixel P is, for example, a photodiode (PD) and is configured to be able to photoelectrically convert light. The photoelectric conversion unit of each pixel P can also be referred to as a photoelectric conversion region or a photoelectric conversion element. The imaging device 1 has a region (pixel unit 100) in which a plurality of pixels P are provided, as in the example shown in FIG. 1 or FIG. 2 . The imaging device 1 has, for example, the pixel unit 100 in which a plurality of pixels P are two-dimensionally arranged in a matrix, as an imaging area. The pixel unit 100 can also be referred to as a pixel array in which a plurality of pixels P are arranged.

[0012] The imaging device 1 captures incident light (image light) from a subject to be measured via an optical system including an optical lens. The imaging device 1 captures an image of the subject formed by the optical lens. The imaging device 1 can generate pixel signals by photoelectrically converting the received light (e.g., visible light, infrared light, etc.). The imaging device 1, which is a photodetector, is a device that can receive light and generate a signal, and can also be called a light-receiving device.

[0013] The pixels P of the imaging device 1 are configured to receive, for example, polarized components of light from a measurement object and generate pixel signals corresponding to the polarized components. The imaging device 1 can generate image data as image information related to the polarization state of light from the measurement object based on the pixel signals of each pixel P. Signals (information) related to the amount of light, polarization direction, etc. of the polarized components of light from the measurement object are acquired, making it possible to confirm, for example, the shape, surface condition, etc. of the object to be measured.

[0014] The imaging device 1 (photodetector) may be configured as an image sensor, for example. The imaging device 1 may be, for example, a complementary metal oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD) image sensor. The imaging device 1 may be used in various electronic devices such as digital still cameras, video cameras, and mobile phones. The photodetector and optical element according to the present disclosure may be applied to various electronic devices or optical devices.

[0015] 2, the incident direction of light from the subject to be measured is the Z-axis direction, the left-right direction on the paper surface perpendicular to the Z-axis direction is the X-axis direction, and the up-down direction on the paper surface perpendicular to the Z-axis and X-axis directions is the Y-axis direction. In the following figures, directions may be indicated based on the direction of the arrow in FIG. 2.

[0016] 1 , the imaging device 1 includes a pixel unit 100, a pixel control unit 111, a signal processing unit 112, a control unit 113, and a processing unit 114. The imaging device 1 is also provided with, for example, a plurality of control lines Lc and a plurality of signal lines Ls. Note that the number and arrangement of pixels P provided in the pixel unit 100 (i.e., pixel array) can be changed as appropriate.

[0017] The control lines Lc are signal lines capable of transmitting signals for controlling the pixels P, and are connected to the pixel control unit 111 and the pixels P of the pixel unit 100. In the example shown in FIG. 1 , a plurality of control lines Lc are wired in the pixel unit 100 for each pixel row made up of a plurality of pixels P arranged in the horizontal direction (row direction). The control lines Lc are configured to transmit control signals for reading out signals from the pixels P.

[0018] The plurality of control lines Lc for each pixel row of the imaging device 1 include, for example, wiring for transmitting signals that control transfer transistors, wiring for transmitting signals that control selection transistors, wiring for transmitting signals that control reset transistors, etc. The control lines Lc can also be referred to as drive lines (or pixel drive lines) that transmit signals that drive the pixels P.

[0019] The signal lines Ls are signal lines capable of transmitting signals from the pixels P, and are connected to the pixels P of the pixel unit 100 and the signal processing unit 112. In the pixel unit 100, for example, one or more signal lines Ls are wired for each pixel column made up of a plurality of pixels P aligned in the vertical direction (column direction). The signal lines Ls are electrically connected to the pixels P, and are configured to be able to transmit signals output from the pixels P.

[0020] In the imaging device 1, multiple signal lines Ls may be provided for one pixel column. For example, the imaging device 1 may have multiple signal lines Ls for each pixel column including multiple pixels P. The number and arrangement of the control lines Lc and signal lines Ls provided in the imaging device 1 are not limited to the example shown in the figure and can be changed as appropriate.

[0021] The pixel control unit 111 is configured to be able to control each pixel P of the pixel unit 100. The pixel control unit 111 is a control circuit and is configured by a plurality of circuits including, for example, a buffer, a shift register, an address decoder, etc. The pixel control unit 111 generates signals for controlling the pixels P and outputs them to each pixel P of the pixel unit 100 via control lines Lc. The pixel control unit 111 is controlled by the control unit 113 and controls the pixels P of the pixel unit 100.

[0022] The pixel control unit 111 generates signals for controlling the pixels P, such as a signal for controlling the transfer transistor, a signal for controlling the selection transistor, and a signal for controlling the reset transistor of the pixel P, and supplies these signals to each pixel P via a control line Lc. The pixel control unit 111 can control reading of pixel signals from each pixel P. The pixel control unit 111 can also be said to be a pixel driving unit (pixel driving circuit) configured to be able to drive each pixel P.

[0023] The signal processing unit 112 is configured to be able to perform signal processing of input pixel signals. The signal processing unit 112 is a signal processing circuit and includes, for example, a load circuit, an AD (Analog-Digital) conversion circuit, a horizontal selection switch, etc. The load circuit is configured, for example, by a current source capable of supplying current to the amplification transistor of the pixel P. As an example, the load circuit forms a source follower circuit together with the amplification transistor of the pixel P.

[0024] The signal processing unit 112 may also have an amplifier circuit configured to be able to amplify signals read out from the pixels P via the signal lines Ls. A load circuit, an amplifier circuit, an AD conversion circuit, etc. may be provided for each of the multiple signal lines Ls, for example. In the imaging device 1, a load circuit, an amplifier circuit, an AD conversion circuit, etc. may be provided for each pixel column of the pixel unit 100.

[0025] The signals output from each pixel P selected and scanned by the pixel control unit 111 are input to the signal processing unit 112 via signal lines Ls. The signal processing unit 112 can perform signal processing such as AD conversion of the signals from the pixel P and CDS (Correlated Double Sampling). The signals from each pixel P transmitted through each signal line Ls are subjected to signal processing by the signal processing unit 112 and output to the processing unit 114.

[0026] The processing unit 114 is configured to acquire signals from each pixel P and perform signal processing. The processing unit 114 is a processing circuit, and is configured, for example, by a circuit that performs various types of signal processing on input pixel signals. The processing unit 114 is configured, for example, to include an arithmetic circuit, a memory circuit, etc.

[0027] The processing unit 114 may perform signal processing on pixel signals input from the signal processing unit 112 and output the processed pixel signals. The processing unit 114 may perform various types of signal processing such as noise reduction processing, interpolation processing, and gradation correction processing. The processing unit 114 may include a processor and a memory.

[0028] The control unit 113 is configured to be able to control each unit of the imaging device 1. The control unit 113 receives an externally provided clock, data instructing an operation mode, etc., and can also output data such as internal information of the imaging device 1. The control unit 113 is a control circuit, and has, for example, a timing generator configured to be able to generate various timing signals.

[0029] The control unit 113 controls the driving of the pixel control unit 111, the signal processing unit 112, etc. based on various timing signals (pulse signals, clock signals, etc.) generated by the timing generator. The control unit 113 may include circuits such as a PLL (Phase Locked Loop) and a DAC (Digital to Analog Converter). The control unit 113 and the processing unit 114 may be configured integrally.

[0030] The pixel unit 100, pixel control unit 111, signal processing unit 112, control unit 113, processing unit 114, etc. may be provided on a single substrate or may be provided separately on multiple substrates. The imaging device 1 may have a stacked structure formed by stacking multiple substrates, for example.

[0031] The pixel control unit 111, the signal processing unit 112, the control unit 113, the processing unit 114, etc. of the imaging device 1 may be provided as, for example, peripheral circuits in a peripheral region of the pixel unit 100. Some or all of the signal processing unit 112, the control unit 113, and the processing unit 114 may be configured integrally.

[0032] 3A and 3B are diagrams illustrating an example of the planar configuration of the imaging device according to the first embodiment. Fig. 3B shows an example of the planar configuration of the semiconductor layer 10 in which the photoelectric conversion unit 12 is provided. Fig. 3A also shows an example of the planar configuration of the optical layer 80 provided above the semiconductor layer 10.

[0033] In the imaging device 1, for example, a plurality of pixels P (pixels P1 and P2 in FIGS. 3A and 3B ) each having a photoelectric conversion unit 12 (i.e., a photoelectric conversion region) are provided so as to be aligned in the horizontal direction (X-axis direction) and vertical direction (Y-axis direction) in the pixel unit 100. Note that the number and arrangement of the pixels P in the pixel unit 100 of the imaging device 1 can be set arbitrarily.

[0034] The optical layer 80 is a layer having a plurality of structures 71, and is provided so as to be stacked on the semiconductor layer 10 in which the photoelectric conversion unit 12 is provided. The optical layer 80 is an optical element (optical member) that utilizes metamaterial (metasurface) technology. The optical layer 80 can be configured as, for example, a metalens (metamaterial lens).

[0035] The imaging device 1 includes an optical layer 80 having structures 71, and is configured to guide incident light toward the photoelectric conversion unit 12. The optical layer 80 is configured, for example, as a lens that condenses light. As in the example shown in FIG. 3A , the pixel P of the imaging device 1 has a region (referred to as an element region 60) in which the structures 71 are provided.

[0036] In the imaging device 1, for example, a minute structure 71 is disposed in each element region 60 of each pixel P of the pixel unit 100. The element region 60 corresponds to one region when the optical layer 80 is divided into regions for each pixel P. In the example shown in FIG. 3A , a plurality of structures 71 are formed in the element region 60. The element region 60 has the structure 71 and a member 75 provided around the structure 71.

[0037] 3A , some of the structures 71 are arranged so as to straddle two adjacent element regions 60. The structures 71 may also be provided on a side that forms a boundary between two adjacent pixels P in the X-axis direction or the Y-axis direction, or on an intersection that forms a boundary between four pixels P (or element regions 60).

[0038] The structures 71 are, for example, structures having a columnar (pillar-like) shape. As an example, the structures 71 are pillars (columnar members) having a prismatic shape. The optical layer 80 has the structures 71 as nanostructures and is configured to guide specific polarization components of incident light.

[0039] The imaging device 1 has, for example, an optical layer 80 including a plurality of structures 71, and is configured to be able to collect light that vibrates in a specific direction, i.e., linearly polarized light. The shape of each structure 71 in the optical layer 80 can be changed as appropriate. The structure 71 may have a circular shape or a polygonal shape in a plan view.

[0040] The member 75 is, for example, a member provided so as to fill the spaces between adjacent structures 71, and can also be called a filling member. The structures 71 can also be said to be provided within the member 75 and disposed so as to replace part of the member 75. The structures 71 are made of, for example, a dielectric material having a refractive index different from that of the member 75. Note that the number and arrangement of the structures 71 are not limited to the example shown in the figure and can be changed as appropriate.

[0041] The plurality of pixels P of the pixel unit 100 include, for example, a pixel P1 that receives a certain polarized component of incident light and performs photoelectric conversion, and a pixel P2 that receives a different polarized component and performs photoelectric conversion. The pixel P1 and the pixel P2 are positioned adjacent to each other in the X-axis direction (or the Y-axis direction). In the pixel unit 100, for example, the pixel P1 and the pixel P2 may be arranged repeatedly.

[0042] Pixel P1 and pixel P2 of the pixel unit 100 are configured to generate pixel signals of different polarization components. For example, pixel P1 generates a pixel signal of a 90° polarization component, and pixel P2 generates a pixel signal of a 0° polarization component. The imaging device 1 can obtain pixel signals of multiple types of polarization components, for example, a pixel signal of a 90° polarization component and a pixel signal of a 0° polarization component.

[0043] 4 is a diagram showing an example of the circuit configuration of a pixel of the imaging device according to the first embodiment. The pixel P has a photoelectric conversion unit 12 (photoelectric conversion element) and a readout circuit 20. The photoelectric conversion unit 12 is configured to receive light and generate a signal. The photoelectric conversion unit 12 (i.e., photoelectric conversion region) is configured to be able to generate electric charges by photoelectric conversion.

[0044] 4, the photoelectric conversion unit 12 is a photodiode (PD) that converts incident light into an electric charge. The photoelectric conversion unit 12 performs photoelectric conversion to generate an electric charge according to the amount of received light. The photoelectric conversion unit 12 can also be referred to as a light receiving unit (light receiving element). The readout circuit 20 is configured to be able to output a signal based on the electric charge generated by photoelectric conversion.

[0045] The readout circuit 20 includes, for example, a transistor TR, a floating diffusion FD, a transistor AMP, a transistor SEL, and a transistor RST, and can read out pixel signals based on charges photoelectrically converted by the photoelectric conversion unit 12 (photoelectric conversion region).

[0046] The transistor TR is configured to be able to transfer charges photoelectrically converted by the photoelectric conversion unit 12 to the floating diffusion FD. The transistor TR is controlled by a signal STR to electrically connect or disconnect the photoelectric conversion unit 12 and the floating diffusion FD. The transistor TR is a transfer transistor. The transistor TR can transfer charges photoelectrically converted and stored in the photoelectric conversion unit 12 to the floating diffusion FD.

[0047] The floating diffusion FD is an accumulation unit configured to be able to accumulate transferred charges. The floating diffusion FD can accumulate charges photoelectrically converted by the photoelectric conversion unit 12. The floating diffusion FD accumulates the transferred charges and converts them into a voltage according to the capacitance of the floating diffusion FD. The floating diffusion FD can also be said to be a holding unit capable of holding charges.

[0048] The transistor AMP is configured to generate and output a signal based on the charge accumulated in the floating diffusion FD. The transistor AMP is an amplifying transistor. The transistor AMP can generate and output a signal based on the charge converted by the photoelectric conversion unit 12.

[0049] The gate of the transistor AMP is electrically connected to the floating diffusion FD, and receives the voltage converted by the floating diffusion FD. The drain of the transistor AMP is connected to, for example, a power supply line that supplies a power supply voltage (power supply voltage VDD in the example shown in FIG. 4).

[0050] The source of the transistor AMP is connected to the signal line Ls via, for example, a transistor SEL. The transistor AMP is configured to generate a signal based on the charge accumulated in the floating diffusion FD, i.e., a signal based on the voltage of the floating diffusion FD, and output the signal to the signal line Ls.

[0051] The transistor SEL is configured to be able to control the output of a pixel signal. The transistor SEL is electrically connected in series to the transistor AMP, for example, as in the example shown in FIG. 4 . The transistor SEL is controlled by a signal SSEL, and is configured to be able to output a signal from the transistor AMP to a signal line Ls. The transistor SEL is a selection transistor. The transistor SEL can control the output timing of the pixel signal.

[0052] The transistor SEL is configured to be able to output a signal based on the charge converted by the photoelectric conversion unit 12. The transistor SEL can output a pixel signal of the pixel P to the signal line Ls. The transistor SEL may be electrically connected in series between the transistor AMP and a power supply line to which a power supply voltage (power supply voltage VDD in FIG. 4) is applied. The transistor SEL may also be omitted as necessary.

[0053] The transistor RST is configured to be able to reset the voltage of the floating diffusion FD. The transistor RST is a reset transistor. In the example shown in FIG. 4, the transistor RST is electrically connected to a power supply line to which a power supply voltage VDD is applied, and is configured to be able to reset the charge of the pixel P.

[0054] The transistor RST is controlled by a signal SRST and can reset the charge accumulated in the floating diffusion FD and reset the voltage of the floating diffusion FD. The transistor RST electrically connects the power supply line and the floating diffusion FD and can discharge the charge accumulated in the floating diffusion FD. The transistor RST can reset the charge accumulated in the photoelectric conversion unit 12 via the transistor TR.

[0055] The readout circuit 20 may be configured to be able to change the conversion gain (i.e., conversion efficiency) when converting electric charge into voltage. The readout circuit 20 may include, for example, a transistor (switching transistor) used to set the conversion gain. As an example, the switching transistor is electrically connected between the floating diffusion FD and the transistor RST.

[0056] In the readout circuit 20, when the switching transistor is turned on, the capacitance added to the floating diffusion FD of the pixel P increases, and the conversion gain (conversion efficiency) when converting charge to voltage is switched. The switching transistor can change the conversion gain by switching the capacitance connected to the gate of the transistor AMP.

[0057] The above-mentioned transistor TR (transfer transistor), transistor AMP (amplification transistor), transistor SEL (selection transistor), transistor RST (reset transistor), and switching transistor are each, for example, a MOS transistor (MOSFET) having gate, source, and drain terminals.

[0058] 4, the transistors TR, AMP, SEL, and RST are each configured as an NMOS transistor. The transistors of the pixel P may be configured as PMOS transistors.

[0059] The pixel control unit 111 (see Figure 1) of the imaging device 1 supplies control signals to the gates of the transistors TR, SEL, RST, switching transistors, etc. of each pixel P via the control line Lc described above, turning the transistors on (conducting state) or off (non-conducting state).

[0060] The multiple control lines Lc for each pixel row of the imaging device 1 include, for example, a wiring for transmitting a signal STR that controls the transistor TR, a wiring for transmitting a signal SSEL that controls the transistor SEL, a wiring for transmitting a signal SRST that controls the transistor RST, and a wiring for transmitting a signal that controls the switching transistor.

[0061] The transistors TR, SEL, RST, and switching transistors are controlled to be turned on and off by the pixel control unit 111. The pixel control unit 111 controls the readout circuit 20 of each pixel P to output a pixel signal from each pixel P to a signal line Ls. The pixel control unit 111 can control the reading out of the pixel signal of each pixel P to the signal line Ls.

[0062] The imaging device 1 may have a configuration in which a plurality of pixels P share one readout circuit 20. The readout circuit 20 may be provided for a plurality of pixels P. For example, in the imaging device 1, a readout circuit 20 is arranged for each of a plurality of pixels P, and the plurality of pixels P share one readout circuit 20. As an example, a 2×2 pixel array consisting of four adjacent pixels P may share one readout circuit 20.

[0063] 5 is a diagram showing an example of a cross-sectional configuration of the imaging device according to the first embodiment. The imaging device 1 has, for example, an optical layer 80, a spacer layer 90, a semiconductor layer 10, and a wiring layer 95. The imaging device 1 has a configuration in which the optical layer 80, the spacer layer 90, the semiconductor layer 10, and the wiring layer 95 are stacked in the Z-axis direction. The optical layer 80, the spacer layer 90, the semiconductor layer 10, and the wiring layer 95 are provided from the light incident side.

[0064] The optical layer 80 has structures 71 and is configured to guide incident light toward the photoelectric conversion unit 12. The optical layer 80 has, for example, a plurality of structures 71 arranged so as to be aligned in the X-axis direction (or the Y-axis direction). The structures 71 have, for example, a columnar shape and can be considered a metasurface element. The optical layer 80 can also be called a metasurface layer or a metamaterial layer.

[0065] The optical layer 80 includes structures 71 and members 75 provided around the structures 71. The structures 71 are, for example, pillars (columnar members) and may also be called nanopillars. The structures 71 and the members 75 are made of materials having different refractive indices. The optical layer 80 including the structures 71 is provided by being stacked on the spacer layer 90.

[0066] The semiconductor layer 10 is composed of a semiconductor substrate (e.g., a Si substrate, an SOI substrate, etc.). The semiconductor layer 10 may be a SiGe (silicon germanium) substrate, a SiC (silicon carbide) substrate, etc., or may be formed using other semiconductor materials. The semiconductor layer 10 may also be composed of a III-V group compound semiconductor material, etc.

[0067] As shown in FIG. 5 , the semiconductor layer 10 has opposing surfaces 11S1 and 11S2. The surface 11S2 is the surface opposite to the surface 11S1. For example, the surface 11S1 of the semiconductor layer 10 is a light-receiving surface (light incident surface). The surface 11S2 of the semiconductor layer 10 is an element formation surface on which elements such as transistors and capacitors are formed. A gate electrode, a gate insulating film (e.g., a gate oxide film), etc. may be provided on the surface 11S2 of the semiconductor layer 10.

[0068] A spacer layer 90 is provided on the surface 11S1 side of the semiconductor layer 10. The optical layer 80 and the spacer layer 90 are stacked on the semiconductor layer 10 in a thickness direction perpendicular to the surface 11S1 of the semiconductor layer 10. A wiring layer 95 is provided on the surface 11S2 side of the semiconductor layer 10. The optical layer 80 is provided on the side where light from the optical system is incident, and the wiring layer 95 is provided on the side opposite to the side where the light is incident.

[0069] In the semiconductor layer 10, a plurality of photoelectric conversion units 12 are provided along the surfaces 11S1 and 11S2 of the semiconductor layer 10. For example, a plurality of photoelectric conversion units 12 are embedded in the semiconductor layer 10. The photoelectric conversion units 12 are provided between the surfaces 11S1 and 11S2 of the semiconductor layer 10. The photoelectric conversion units 12 are photoelectric conversion regions and can also be referred to as photoelectric conversion layers. The photoelectric conversion units 12 perform photoelectric conversion on light incident via the optical layer 80 and the spacer layer 90.

[0070] The wiring layer 95 is provided by being laminated on the semiconductor layer 10. The wiring layer 95 includes, for example, a conductor film and an insulating film, and has a plurality of wirings and vias. The wiring layer 95 has a configuration in which a plurality of wirings are laminated via an insulating film serving as an interlayer insulating film (interlayer insulating layer). The wiring layer 95 is configured as, for example, a multi-layer wiring layer, and includes two or more layers of wirings, or three or more layers of wirings.

[0071] The wiring of the wiring layer 95 is formed using a metal material such as aluminum (Al), tungsten (W), copper (Cu), etc. The wiring of the wiring layer 95 may be formed using polysilicon (Poly-Si) or other conductive materials. The interlayer insulating film is formed using, for example, silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), etc. The interlayer insulating film may be formed using other insulating materials.

[0072] The semiconductor layer 10 and the wiring layer 95 are provided with, for example, the above-described readout circuit 20 (see FIG. 4 ) for each pixel P or for each set of pixels P (i.e., for each predetermined number of pixels P). The above-described pixel control unit 111, signal processing unit 112, control unit 113, processing unit 114 (see FIG. 1 ), etc. may be provided on the semiconductor layer 10 and the wiring layer 95, or on a substrate separate from the semiconductor layer 10.

[0073] The spacer layer 90 is provided between the semiconductor layer 10 and the optical layer 80. The spacer layer 90 is made of an insulating film such as an oxide film, a nitride film, or an oxynitride film, and can also be called an insulating layer. The spacer layer 90 may be made of an insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or aluminum oxide (AlO), or may be made of other materials.

[0074] The spacer layer 90 (insulating layer) may be made of, for example, a material with a low refractive index, such as silicon oxide. The spacer layer 90 may also be made of another material that transmits light in the wavelength band to be measured. The spacer layer 90 can also be considered a transparent layer that transmits light.

[0075] The imaging device 1 may have an isolation region 40, as in the example shown in Fig. 5. The isolation region 40 is an isolation region (isolation portion) provided around a pixel P (or a photoelectric conversion portion 12). The isolation region 40 is provided between adjacent pixels P in the semiconductor layer 10, and separates the pixels P (or the photoelectric conversion portions 12). The isolation region 40 is configured using, for example, a trench (groove portion).

[0076] The isolation region 40 is provided, for example, so as to surround the photoelectric conversion unit 12 on all four sides in a plan view (i.e., when viewed in the XY plane) (see also FIG. 3B ). The isolation region 40 may be formed in a lattice pattern in the semiconductor layer 10 so as to surround the photoelectric conversion unit 12 of each pixel P. At least a portion of the isolation region 40 is provided at the boundary between adjacent pixels P. The isolation region 40 can also be referred to as an inter-pixel isolation portion or an inter-pixel isolation wall. The isolation region 40 may be provided so as to penetrate the semiconductor layer 10.

[0077] As an example, the isolation region 40 has a full trench isolation (FTI) structure and is formed to reach the surface 11S2 of the semiconductor layer 10. The isolation region 40 may be provided from the surface 11S1 of the semiconductor layer 10 to between the surfaces 11S1 and 11S2 of the semiconductor layer 10. An insulating film, such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or an aluminum oxide film, is provided in the trench of the isolation region 40.

[0078] The trenches of the isolation region 40 may be filled with polysilicon, a metal material, another insulating material, or the like. The isolation region 40 may also be formed using another insulating material with a low refractive index. A void (cavity) may be provided within the isolation region 40. The isolation region 40 may be composed of a semiconductor region (p-type or n-type semiconductor region) formed by ion implantation.

[0079] A light-shielding member (light-shielding portion) may be provided as the isolation region 40. For example, a material that absorbs light is provided inside the trench of the isolation region 40. As an example, tungsten (W) may be embedded in the trench of the isolation region 40. The isolation region 40 may be made of polysilicon. The isolation region 40 may also be formed using other materials that block light. The isolation region 40 is made of a light-shielding member and can also be called a light-shielding wall.

[0080] In the imaging device 1, the provision of the separation region 40 prevents the electric charge converted by the photoelectric conversion unit 12 of the pixel P from leaking to the surrounding pixels P (or the photoelectric conversion unit 12). Furthermore, it is possible to prevent unnecessary light from leaking to the surrounding pixels P, thereby suppressing crosstalk between pixels. It is also possible to prevent noise from being mixed into the pixel signal.

[0081] The imaging device 1 may have a filter configured to selectively transmit light of a specific wavelength band from the incident light. The filter may be a primary color (RGB) color filter, a complementary color (CMY) color filter, a filter that transmits infrared light, or the like. The filter is provided above the photoelectric conversion unit 12, for example, for each pixel P or for each set of multiple pixels P. The filter may be provided, for example, in the spacer layer 90, between the optical layer 80 and the semiconductor layer 10.

[0082] The imaging device 1 may also have at least one of a fixed charge film and an anti-reflection film on the surface 11S1 side of the semiconductor layer 10. The fixed charge film and the anti-reflection film may be made of, for example, a metal compound (such as a metal oxide or a metal nitride) and may also be referred to as a metal compound layer. The fixed charge film is a film having a fixed charge and may be formed using a high-dielectric material.

[0083] The fixed charge film is, for example, made of a metal oxide such as aluminum oxide or hafnium oxide. The fixed charge film is, for example, a film having a negative fixed charge. A portion of at least one of the fixed charge film and the antireflection film may be provided along the sidewall (side surface) of the isolation region 40 in the semiconductor layer 10.

[0084] In the imaging device 1, the fixed charge film is provided to suppress the generation of dark current at the interface of the semiconductor layer 10. The fixed charge film may be formed of another metal oxide film, or may be formed using a metal nitride film or a metal oxynitride film. In the imaging device 1, a film having a positive fixed charge may be provided as the fixed charge film.

[0085] The antireflection film is made of, for example, a metal oxide such as hafnium oxide or tantalum oxide. The antireflection film (anti-reflection film) is provided on the surface 11S1 side of the semiconductor layer 10 to reduce (suppress) reflection. The antireflection film is provided, for example, so as to be stacked with the fixed charge film. The antireflection film may be made of an insulating material such as silicon nitride, silicon oxide, or aluminum oxide, or may be made of other materials.

[0086] As in the example shown in Fig. 5 , the optical layer 80 has a plurality of structures 71 and is provided above the photoelectric conversion unit 12. The optical layer 80 has structures 71 that are nanostructures and is configured to guide light incident from above in Fig. 5 toward the photoelectric conversion unit 12. For example, light that has passed through an optical system (not shown) such as an imaging lens is incident on the optical layer 80. Light from a subject as a measurement object is incident on the structures 71 of the optical layer 80 via the optical system.

[0087] The optical layer 80 utilizes the structure 71, which is a nanostructure, to propagate light toward the photoelectric conversion unit 12. The structure 71 is also called, for example, a nanopillar, a metaatom, a nanoatom, a nanopost, a metasurface structure, or a microstructure. The optical layer 80 is an optical element (optical member) that guides (propagates) light.

[0088] The plurality of structures 71 of the optical layer 80 are arranged two-dimensionally in the X-axis direction and the Y-axis direction, as in the examples shown in Fig. 3A and Fig. 5. The structures 71 have a size that is equal to or smaller than a predetermined wavelength of incident light, for example, in a plan view (i.e., when viewed on the XY plane).

[0089] When viewed in the XY plane, the structure 71 has a size equal to or smaller than the wavelength range of light to be measured, for example, equal to or smaller than the wavelength range of visible light. The structure 71 may also have a size equal to or smaller than the wavelength range of infrared light. Note that the size of the structure 71 when viewed in the XZ plane or YZ plane (for example, the height of the columnar structure 71) may be equal to or smaller than a predetermined wavelength of the incident light, or may be larger than the wavelength of the incident light.

[0090] The multiple structures 71 in each element region 60 are arranged side by side in the X-axis direction or the Y-axis direction, with part of the member 75 sandwiched between them. As an example, the structures 71 have a prismatic shape. The shape of the structures 71 may be a quadrangle in plan view. Note that the shape of the structures 71 can be changed as appropriate, and may be an ellipse, a cross, or another shape.

[0091] 5 , the member 75 is provided between adjacent structures 71. The member 75 is a member located around the structures 71 and can also be called a support member or a material layer. The member 75 may be formed so as to cover the structures 71. For example, a portion of the member 75 may be located above the structures 71. A portion of the member 75 may be provided below the structures 71.

[0092] The optical layer 80 is configured to, for example, impart a phase delay to incident light and guide the light. A plurality of structures 71 are provided on the optical layer 80 so as to impart a desired phase profile to the incident light. For example, the material of the structures 71 (optical constants of the structures 71), size (width (diameter), height, etc.) of the structures 71, number of structures 71 arranged, arrangement interval (pitch), etc. are determined so that polarized light to be detected is focused onto a predetermined photoelectric conversion unit 12.

[0093] In the optical layer 80, for example, the plurality of structures 71 are arranged at intervals equal to or less than a predetermined wavelength of incident light. As an example, the plurality of structures 71 are provided at intervals equal to or less than the wavelength range of visible light in the X-axis direction and the Y-axis direction. The plurality of structures 71 may also be arranged at intervals equal to or less than the wavelength range of infrared light in the XY plane.

[0094] The structure 71 is configured to have a refractive index different from that of the adjacent medium. The structure 71 has a refractive index different from that of the material or void surrounding the structure 71, for example, the member 75. The structure 71 and the member 75 may be made of different materials. For example, the structure 71 is made of a material having a relatively high refractive index.

[0095] The structure 71 is made of, for example, a material having a refractive index higher than that of the member 75. The structure 71 has a refractive index higher than that of the member 75. The structure 71 is made of a high refractive index material and can also be called a high refractive index portion. The member 75 is made of a low refractive index material and can also be called a low refractive index portion. The member 75 can also be called a material layer having a refractive index different from that of the structure 71.

[0096] The structure 71 is formed, for example, by an oxide film containing titanium (Ti). As an example, the structure 71 is formed using titanium oxide (TiO). As other examples, the structure 71 may be formed using silicon, polysilicon (Poly-Si), amorphous silicon (a-Si), germanium (Ge), or the like. The structure 71 may also be formed using silicon carbide (SiC) or other silicon compounds.

[0097] The structure 71 may be made of other metal compounds (metal oxides, metal nitrides, etc.). The structure 71 may be made of titanium (Ti), hafnium (Hf), aluminum (Al), zirconium (Zr), tantalum (Ta), indium (In), niobium (Nb), or the like, or an element, oxide, nitride, oxynitride, or a composite thereof. The structure 71 may be made of GaP, GaN, GaAs, etc.

[0098] The member 75 is made of an inorganic material such as an oxide, a nitride, or an oxynitride. The member 75 may be made of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), or the like. The member 75 may also be formed using silicon carbide, silicon oxycarbide, silicon carbonitride, or other silicon compounds.

[0099] The member 75 may be made of a siloxane-based resin, a styrene-based resin, an acrylic-based resin, or the like. The member 75 may be made of a material in which any of these resins contains fluorine. The member 75 may be formed using a material in which any of these resins is filled with beads (filler) having a refractive index higher (or lower) than that of the resin.

[0100] The materials constituting the structure 71 and the member 75 can be selected depending on the refractive index difference with the surrounding materials, the wavelength range of light to be measured, etc. The structure 71 and the member 75 may each be made of an inorganic material or an organic material. The structure 71 or the member 75 may be made of a void (cavity). For example, the member 75 may be made to include air (void).

[0101] The optical layer 80 is configured to cause a phase delay in incident light due to, for example, a difference in refractive index between the structure 71 and the surrounding medium, thereby controlling the wavefront of the light. The optical layer 80 can adjust the propagation direction of the light by imparting a phase delay to the incident light using the structure 71 and the member 75 surrounding the structure 71. The light to which the phase is imparted by the optical layer 80 propagates through the spacer layer 90 and reaches the photoelectric conversion unit 12.

[0102] In each pixel P of the imaging device 1, for example, the effective refractive index is adjusted according to the occupancy rate (filling rate) of the structures 71, and the amount of phase delay of light is set. The amount of phase delay can be controlled and a desired phase distribution can be achieved by adjusting the shape, size, and number of the structures 71 in each pixel P. The constituent materials of the structures 71 and the member 75, the shape and size of the structures 71, the spacing between the structures 71, and the like are determined so that light of any polarization direction among the incident light travels in a desired direction.

[0103] The optical layer 80 is configured as a spectroscopic unit (spectroscopic element) that can separate polarized light from incident light. The optical layer 80 is a polarization separation element (i.e., a metasurface polarization separation element) and can be configured as a polarization separation lens. The optical layer 80 can also be called a polarization separation layer or a polarization separation metasurface layer. The optical layer 80 can selectively guide a predetermined polarization component contained in the incident light to the photoelectric conversion unit 12.

[0104] The optical layer 80 can separate incident light into each polarization component by, for example, imparting a different amount of phase delay depending on the polarization direction of the light. In the imaging device 1, the shape, size, arrangement number, etc. of the structures 71 in the region of the optical layer 80 corresponding to the pixel P are determined so that a specific polarization to be detected is separated and travels to the photoelectric conversion unit 12 of the desired pixel P.

[0105] As described above, polarized components of light from a subject to be measured are incident on the photoelectric conversion unit 12 of each pixel P of the imaging device 1 via the optical layer 80. Each pixel P can photoelectrically convert the polarized light incident via the optical layer 80 to generate a pixel signal. The imaging device 1 can generate image data representing an image of the subject using, for example, the pixel signals obtained by each pixel P. Image data (image information) representing the shape, surface condition, etc. of the subject can be obtained using the pixel signals based on the polarized components.

[0106] 6 and 7 are diagrams for explaining an example configuration of the imaging device according to the first embodiment. Fig. 6 shows an example of the planar configuration of the imaging device 1, and Fig. 7 shows an example of the cross-sectional configuration of the imaging device 1. The white arrows in Fig. 7 schematically show light incident on the optical layer 80 including the structures 71. Polarized light L1 and polarized light L2, respectively indicated by dashed arrows, are different polarization components of light from the measurement object.

[0107] Polarized light L2 is light (light component) having a polarization direction different from the polarization direction of polarized light L1. Polarized light L1 and polarized light L2 are, for example, linearly polarized light that is orthogonal to each other. Polarized light L2 has a polarization direction that is orthogonal to the polarization direction of polarized light L1. As an example, polarized light L1 is 90° polarized and polarized light L2 is 0° polarized. For example, the polarization direction of polarized light L1, i.e., the vibration direction of the electric field of polarized light L1, is the Y-axis direction (depth direction).

[0108] Furthermore, for example, the polarization direction of polarized light L2, i.e., the vibration direction of the electric field of polarized light L2, is the X-axis direction (left-right direction). Polarized light L1 is the Y-direction polarization component of the incident light, and polarized light L2 is the X-direction polarization component of the incident light. Note that polarized light L1 and polarized light L2 guided by the optical layer 80 may each be other polarization components (e.g., 45° polarization, 135° polarization, etc.).

[0109] The multiple pixels P of the imaging device 1 include pixel P1 and pixel P2. Pixel P1 receives polarized light L1 in the photoelectric conversion unit 12 and performs photoelectric conversion. Pixel P2 receives polarized light L2 in the photoelectric conversion unit 12 and performs photoelectric conversion. Pixel P2 is provided adjacent to pixel P1. The pixel unit 100 may have, for example, pixel rows in which pixels P1 and pixels P2 are provided alternately.

[0110] The optical layer 80 of the imaging device 1 has a region (referred to as a light-collecting region 81) that collects polarized light L1 (e.g., 90° polarized light) of incident light, and a region (referred to as a light-collecting region 82) that collects polarized light L2 (e.g., 0° polarized light). The light-collecting region 81 and the light-collecting region 82 adjust the traveling directions of the polarized light L1 and the polarized light L2, respectively.

[0111] 6 and 7 , the light-collecting region 81 is provided for the pixel P1. For example, the light-collecting region 81 is provided corresponding to the pixel P1 and a part of the pixel P2 adjacent to the pixel P1. When viewed from above the optical layer 80, the light-collecting region 81 is positioned so as to overlap with the photoelectric conversion unit 12 of the pixel P1 and at least a part of the photoelectric conversion unit 12 of the pixel P2.

[0112] 6 and 7 , the light-collecting region 82 is provided for the pixel P2. The light-collecting region 82 is provided, for example, to correspond to the pixel P2 and a part of the pixel P1 adjacent to the pixel P2. When viewed from above the optical layer 80, the light-collecting region 82 is positioned so as to overlap with the photoelectric conversion unit 12 of the pixel P2 and at least a part of the photoelectric conversion unit 12 of the pixel P1.

[0113] The optical layer 80 has, for example, a plurality of light-collecting regions 81, the number of which corresponds to the number of pixels P1 in the pixel unit 100. The optical layer 80 also has a plurality of light-collecting regions 82, the number of which corresponds to the number of pixels P2 in the pixel unit 100. The light-collecting regions 81 in the optical layer 80 can be configured as regions that overlap with parts of the light-collecting regions 82.

[0114] For example, the light collection region 81 overlaps with a part of the light collection region 82 and includes a part of the light collection region 82. Furthermore, the light collection region 82 overlaps with a part of the light collection region 81 and includes a part of the light collection region 81. The light collection region 81 and the light collection region 82 partially overlap each other. The light collection region 81 and the light collection region 82 are regions that overlap each other, and can also be said to be provided so as to overlap each other.

[0115] The light collecting region 81 and the light collecting region 82 may each have a light receiving area larger than the area of ​​one pixel P, for example, a light receiving area that is approximately twice the area of ​​one pixel P. For example, in a plan view (i.e., when viewed on the XY plane), the light receiving area of ​​each of the light collecting region 81 and the light collecting region 82 is twice the area of ​​the pixel P.

[0116] The imaging device 1 is configured so that the center position of the light collection region 81 is different from the center position of the light collection region 82. In a direction (e.g., the X-axis direction) perpendicular to the stacking direction (the Z-axis direction) of the optical layer 80 and the semiconductor layer 10, the center position of the light collection region 81 is different from the center position of the light collection region 82. In the examples shown in Figures 6 and 7, the center of the light collection region 81 is located away from the center of the light collection region 82 in the horizontal direction (the X-axis direction).

[0117] The optical layer 80 may be configured, for example, so that the center positions of the light collection regions 81 and 82 are displaced (shifted) in the polarization separation direction (e.g., the X-axis direction). The light collection regions 81 and 82 can also be referred to as openings (aperture regions) for the polarized light L1 and the polarized light L2, respectively.

[0118] The light-collecting region 81 corresponding to the pixel P1 and a part of the pixel P2 is configured to be able to propagate polarized light L1 of the incident light to the photoelectric conversion unit 12 of the pixel P1. The light-collecting region 82 corresponding to the pixel P2 and a part of the pixel P1 is configured to propagate polarized light L2 of the incident light to the photoelectric conversion unit 12 of the pixel P2.

[0119] The light-collecting regions 81 and 82 of the optical layer 80 separate the incident light into its respective polarization components, and guide the polarized light L1 toward the pixel P1 and the polarized light L2 toward the pixel P2. The light-collecting region 81 is configured to guide the polarized light L1 of the incident light to the photoelectric conversion unit 12 of the pixel P1. As indicated by the dashed arrow in Figure 7, the optical layer 80 collects the polarized light L1 incident on the light-collecting region 81 to the photoelectric conversion unit 12 of the pixel P1.

[0120] The light-collecting region 82 of the optical layer 80 is configured to guide polarized light L2, which is a polarization component of the incident light that is different from the polarized light L1, to the photoelectric conversion unit 12 of the pixel P2. As indicated by the dashed arrow in Fig. 7 , the optical layer 80 collects the polarized light L2 that is incident on the light-collecting region 82 to the photoelectric conversion unit 12 of the pixel P2.

[0121] In this embodiment, polarized light L1 incident on a light-collecting region 81 including the element region 60 of pixel P1 and a part of the element region 60 of pixel P2 can be collected onto the photoelectric conversion unit 12 of pixel P1. Also, polarized light L2 incident on a light-collecting region 82 including the element region 60 of pixel P2 and a part of the element region 60 of pixel P1 can be collected onto the photoelectric conversion unit 12 of pixel P2.

[0122] The photoelectric conversion unit 12 of each of the pixels P1 and P2 can efficiently receive the polarized component of light from the measurement target, perform photoelectric conversion, and generate charges according to the amount of received light. For example, as in the example shown in Figure 7, it is possible to collect light onto the pixel from a light collection region having an area twice the area of ​​one pixel, thereby improving the sensitivity of the pixels P1 and P2.

[0123] Furthermore, as described above, the imaging device 1 is configured so that the center position of the light collection region 81 is different from the center position of the light collection region 82. The center of the light collection region 81 may be located near the center of the pixel P1, and the center of the light collection region 82 may be located near the center of the pixel P2. This makes it possible to reduce the angle at which light is bent, which is necessary to collect light onto the photoelectric conversion unit 12 of the pixel P. It becomes possible to appropriately guide light from the measurement target to the photoelectric conversion unit 12. Below, the imaging device 1 according to this embodiment will be further described in comparison with a comparative example.

[0124] 8 and 9 are diagrams showing an example of the configuration of an imaging device according to the first embodiment. Fig. 9 shows an example of a cross-sectional configuration in a region where the distance from the center of the pixel unit 100 (pixel array) is higher, i.e., the image height is higher, than in the case of Fig. 8. Light from the optical lens is incident almost perpendicularly on the central portion of the pixel unit 100 of the imaging device 1, as shown by the outline arrow in Fig. 8. Light is incident obliquely on the peripheral portion located outside the central portion, i.e., on the region farther from the center of the pixel unit 100, as shown by the outline arrow in Fig. 9.

[0125] 10 and 11 are diagrams showing an example of the configuration of an imaging device according to a comparative example. In the comparative example, the center position of light collection region 81 and the center position of light collection region 82 are the same, and the centers of light collection regions 81 and 82 are located on the boundary between pixel P1 and pixel P2. In the comparative example, as shown in FIG. 10 , for example, the maximum bending angle θc of light from the measurement target becomes large, which may prevent light from being efficiently collected from adjacent pixels onto the photoelectric conversion unit 12 of the desired pixel P.

[0126] 10 and 11, the change in phase delay (i.e., the slope) required to focus light on the photoelectric conversion unit 12 of the pixel P becomes steep, which may cause the wavefront of the light to become more easily disturbed (disintegrated). It is considered that the influence of manufacturing errors of the nanopillars on the light-focusing performance becomes large. In the case of perpendicular incident light shown in FIG. 10, and also in the case of oblique incident light shown in FIG. 11, the amount of light transmitted (incident) to the photoelectric conversion unit 12 of the target pixel P may decrease, which may result in a decrease in the sensitivity of the pixel P.

[0127] In this embodiment, as described above, the optical layer 80 is configured so that the central positions of the light collection regions 81 and 82 are different from each other. Therefore, as shown in the example in Fig. 8 , the maximum bending angle θi of light from the measurement target is small (θi < θc), and light can be efficiently collected from adjacent pixels onto the photoelectric conversion unit 12 of the desired pixel P.

[0128] In the case of the imaging device 1 according to this embodiment, it is possible to reduce (relax) the amount of change (gradient) in the phase delay required to focus light on the photoelectric conversion unit 12 of the pixel P. This reduces the influence of manufacturing errors of the nanopillar structures 71 on the light-focusing performance. It is possible to prevent a decrease in the amount of light passing through to the photoelectric conversion unit 12 of the target pixel P. It is possible to improve the light-focusing performance.

[0129] 9 , it is possible to appropriately collect light from an area wider than the size of one pixel onto the photoelectric conversion unit 12 of the target pixel P. It is also possible to improve the sensitivity to incident light in pixels P in regions with low image heights (i.e., pixels P in the central region of the pixel unit 100) and pixels P in regions with high image heights (i.e., pixels P in the peripheral region of the pixel unit 100).

[0130] 12 and 13 are diagrams showing another example of the configuration of the imaging device according to the first embodiment. Fig. 13 shows an example of the cross-sectional configuration in a region where the image height is higher than that in Fig. 12. The imaging device 1 can be configured, for example, as shown in Fig. 12, so that the center of the light-collecting region 81 and the center of the pixel P1 are located on the same axis. In the example shown in Fig. 12, the center of the light-collecting region 81 and the center of the pixel P1 are located on the same axis A1.

[0131] Furthermore, the imaging device 1 may be configured so that the center of the light collection region 82 and the center of the pixel P2 are located on the same axis. In the example shown in Fig. 12, the center of the light collection region 82 and the center of the pixel P2 are located on the same axis A2. The light collection region 81 and the light collection region 82 may be formed so that the centers of the light collection region 81 and the light collection region 82 are offset from each other by one pixel in the X-axis direction.

[0132] By configuring the imaging device 1 in this manner, the bending angle of light can be made smaller, and therefore polarized light (polarized light L1, polarized light L2, etc.) can be efficiently collected onto the photoelectric conversion unit 12 of the target pixel P. In both the case of perpendicular incidence in FIG. 12 and the case of oblique incidence in FIG. 13, the light collection efficiency can be improved, and sensitivity can be further improved.

[0133] 14A and 14B are diagrams illustrating an example of the configuration of the imaging device according to the first embodiment. Fig. 14A shows an example of the planar configuration of the optical layer 80 of the imaging device 1. In the example shown in Fig. 14 , the center of the light-collecting region 81 and the center of the pixel P1 are located on the same axis (axis A1), and the center of the light-collecting region 82 and the center of the pixel P2 are located on the same axis (axis A2).

[0134] 14B shows an example of a phase distribution formed by the optical layer 80. In FIG. 14B, the vertical axis represents the phase shift amount (i.e., the phase delay amount), and the horizontal axis represents the position in the X-axis direction. FIG. 14B illustrates the phase delay amount imparted to polarized light L1 (e.g., 90° polarized light) and polarized light L2 (e.g., 0° polarized light).

[0135] The optical layer 80 of the imaging device 1 is configured so that, for example, the structures 71 (pillars) positioned at equal distances from the axis A1 (or axis A2) as the axis of symmetry have the same shape. Furthermore, some of the structures 71 in the optical layer 80 may be provided on the boundaries between adjacent pixels P.

[0136] In the example shown in FIG. 14A , a portion of the structure 71 is provided at the boundary between pixel P1 and pixel P2, which are adjacent in the X-axis direction. The shape of the structure 71 provided at the boundary between pixel P1 and pixel P2 may have rotational symmetry. For example, the structure 71 located at the pixel boundary is configured to have 90° rotational symmetry (i.e., four-fold symmetry). By configuring the imaging device 1 in this manner, it is possible to ensure the symmetry of the PSF (Point Spread Function).

[0137] [Actions and Effects] The photodetector according to this embodiment includes a semiconductor layer (semiconductor layer 10), a first photoelectric conversion region and a second photoelectric conversion region provided in the semiconductor layer, and an optical layer (optical layer 80) provided above the semiconductor layer and having a plurality of first structures (structures 71). The optical layer includes a first region (e.g., light-collecting region 81) corresponding to the first photoelectric conversion region and a second region (e.g., light-collecting region 82) corresponding to the second photoelectric conversion region. The center position of the first region is different from the center position of the second region. The optical layer guides first polarized light (e.g., polarized light L1) incident on the first region to the first photoelectric conversion region, and guides second polarized light (e.g., polarized light L2) incident on the second region, which is different from the first polarized light, to the second photoelectric conversion region.

[0138] The photodetector (imaging device 1) according to this embodiment includes an optical layer 80 having a plurality of structures 71. The optical layer 80 includes a light-collecting region 81 corresponding to the photoelectric conversion region (photoelectric conversion unit 12) of pixel P1 and a light-collecting region 82 corresponding to the photoelectric conversion region of pixel P2. The center position of the light-collecting region 81 is different from the center position of the light-collecting region 82. In this embodiment, incident light can be efficiently guided to the photoelectric conversion region. It is possible to realize a photodetector capable of efficiently collecting light.

[0139] Next, a modified example of the present disclosure will be described. In the following, the same components as those in the above embodiment will be denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0140] (Variation 1) In the above-described embodiment, an example configuration of the imaging device has been described, but the configuration of the imaging device is not limited to the above-described example. For example, the shape of the structure 71 of the imaging device 1 is not limited to the example shown in the drawings and can be modified as appropriate. Fig. 15 is a diagram showing an example configuration of a structure of an imaging device according to Variation 1 of the present disclosure. For example, as in the examples shown in Figs. 15(A) and 15(B), the structure 71 may have a prismatic shape. The shape of the structure 71 may be a rectangular parallelepiped.

[0141] 16 and 17 are diagrams showing other configuration examples of the structure of the imaging device according to Modification 1. The shape of the structure 71 may be elliptical or + (plus) shaped in a plan view. For example, the structure 71 may have an elliptical cylindrical shape as in the example shown in FIGS. 16(A) and (B). The structure 71 may have a + (plus) shape as in the example shown in FIGS. 17(A) and (B).

[0142] (Modification 2) Fig. 18 is a diagram for explaining a configuration example of an imaging device according to Modification 2. Structures 71 as microstructures (nanostructures) may be periodically arranged in the optical layer 80, for example. For example, as shown in the example of Fig. 18, the structures 71 may be arranged at the intersections of a grid of dashed lines arranged at equal intervals. By arranging the structures 71 in this manner, it is possible to ensure the symmetry of the PSF.

[0143] 19, 20A, and 20B are diagrams for explaining a configuration example of an imaging device according to Modification 3. FIGS. 20A and 20B show an example of a planar configuration of different layers of the imaging device. The imaging device 1 may have a multi-layer (multi-stage) structure 71. The optical layer 80 of the imaging device 1 has a plurality of structures, for example, structures 71a and structures 71b, stacked on top of each other. The element region 60 of each pixel P may be provided with a first-stage structure 71a and a second-stage structure 71b.

[0144] 19 and other drawings, the optical layer 80 includes an optical layer 181 (first layer) including structures 71a and members 75a, and an optical layer 182 (second layer) including structures 71b and members 75b. The optical layer 182 is stacked on the optical layer 181. The structures 71a and 71b each have, for example, a columnar shape.

[0145] The structures 71a and the members 75a may be made of materials having different refractive indices. The structures 71b and the members 75b may be made of materials having different refractive indices. The shapes and numbers of the structures 71a and 71b are not limited to the illustrated example and may be changed as appropriate.

[0146] In the imaging device 1 according to this modification, the optical layer 80 having multiple layer structures (e.g., structures 71a and 71b) can appropriately guide light to the photoelectric conversion unit 12. The multiple-stage metasurface element can efficiently focus any polarized light onto the photoelectric conversion unit 12. It is possible to realize an optical layer 80 (metasurface layer) with good optical properties.

[0147] (Variation 4) Fig. 21 is a diagram illustrating an example configuration of an imaging device according to Variation 4. The imaging device 1 may have an anti-reflection film (anti-reflection film). In the example shown in Fig. 21, the imaging device 1 has anti-reflection films 45a and 45b. The anti-reflection film 45a is provided on the side of the structure 71 on which light is incident. The anti-reflection film 45a is formed on the upper surface of the structure 71. The anti-reflection film 45a is provided so as to cover, for example, a plurality of structures 71.

[0148] The antireflection film 45b is provided on the side of the structure 71 opposite to the side on which light is incident. The antireflection film 45b is formed on the lower surface (bottom surface) of the structure 71. In the example shown in Fig. 21 , the antireflection film 45b is provided between the spacer layer 90 and the structure 71. Each of the antireflection films 45a, 45b is made of, for example, a material having a refractive index different from the refractive index of the structure 71.

[0149] In the imaging device 1, the provision of antireflection films 45a and 45b can reduce (suppress) reflection. Note that the imaging device 1 may have a multi-layer structure 71, and may have an antireflection film 45c in addition to the antireflection films 45a and 45b, as in the example shown in FIG. 22 . Note that the antireflection films 45a to 45c can also be considered part of the optical layer 80.

[0150] 23 and 24 are diagrams for explaining a configuration example of an imaging device according to Modification 5. FIG. 24 schematically shows an example of a cross-sectional configuration in a region where the distance from the center of the pixel unit 100, i.e., the image height, is higher than in the case of FIG. 23 . In the imaging device 1, the element region 60 having the structures 71 can be configured differently depending on the distance from the center of the pixel unit 100, i.e., the image height. For example, in the central region of the pixel unit 100, the pixel P is configured as shown in FIG. 23 .

[0151] In a region away from the center of the pixel unit 100, an element region 60 having a plurality of structures 71 is disposed, for example, shifted toward the center of the pixel unit 100 with respect to the photoelectric conversion unit 12 in accordance with the incident direction of light from the measurement target. In the example shown in FIG. 24 , the element region 60 is disposed shifted leftward with respect to the photoelectric conversion unit 12 of the pixel P.

[0152] The center of the element region 60 of the pixel P is located closer to the center of the pixel unit 100 than the center of the photoelectric conversion unit 12 of the pixel P. In addition, in a region away from the center of the pixel unit 100, the light collecting region 81 and the light collecting region 82 of the optical layer 80 can be shifted toward the center of the pixel unit 100, or to the left in the example shown in FIG.

[0153] In the pixel unit 100 of the imaging device 1, the positions of the structures 71 and the element region 60, etc., are adjusted according to the image height, allowing for appropriate pupil correction. This makes it possible to suppress a decrease in the amount of polarized light incident on the photoelectric conversion unit 12 of each pixel P, and to suppress a decrease in sensitivity to incident light. In this modified example, it is possible to improve the light-collection performance.

[0154] 25 is a diagram illustrating an example configuration of an imaging device according to Modification 6. The spacer layer 90 may be composed of a plurality of members, for example, members 91 and 92. The members 91 and 92 are made of materials having different refractive indices. By configuring the spacer layer 90 using the members 91 and 92, it is possible to improve the light-collecting performance and realize a low-profile imaging device 1.

[0155] 26 and 27 are diagrams illustrating an example configuration of an imaging device according to Modification 7. Fig. 26 shows an example cross-sectional configuration of the imaging device 1. Fig. 27 shows an example planar configuration of a spacer layer 90 of the imaging device 1. The spacer layer 90 has a member 93 and a member 94 provided around the member 93.

[0156] The member 94 is made of, for example, a material having a refractive index lower than that of the member 93. The member 94 has a refractive index lower than that of the member 93. For example, the member 93 is made of a high refractive index material and can also be called a high refractive index portion. The member 94 is made of a low refractive index material and can also be called a low refractive index portion.

[0157] In each pixel P of the imaging device 1, for example, a member 93 is provided as a central region and a member 94 is provided as a peripheral region. The members 93 and 94 are located between the optical layer 80 and the semiconductor layer 10. The member 94 can also be referred to as a separation wall or a light-guiding wall. The members 94 and 93 can also be referred to collectively as a separation wall (or a light-guiding wall).

[0158] 27 , the member 94 can be provided so as to surround the member 93 in a plan view (i.e., when viewed on the XY plane). The member 94 has a predetermined thickness and is disposed so as to surround the member 93 on all four sides. A portion of the member 94 is provided at the boundary between adjacent pixels P.

[0159] In the imaging device 1 according to this modification, the provision of members 93 and 94 allows light to be appropriately guided to the photoelectric conversion unit 12, as shown in the example schematically indicated by the dashed arrow in Fig. 28. This makes it possible to suppress deterioration of optical characteristics with respect to obliquely incident light, and improve the light-collection efficiency of pixels P in areas with high image heights.

[0160] 29 is a diagram illustrating another example configuration of an imaging device according to Modification Example 7. As in the example shown in Fig. 29 , members 94 may be provided to sandwich member 93 in a direction perpendicular to the thickness direction of spacer layer 90 (i.e., the Z-axis direction), for example, in the Y-axis direction. Members 94 may be arranged on both sides (both ends) of member 93.

[0161] In the imaging device 1, the traveling direction of incident light is changed by the difference in refractive index between the members 93 and 94. As indicated by the arrows in Fig. 30 , part of the light that has passed through the optical layer 80 is reflected at the interface between the members 93 and 94 and guided toward the photoelectric conversion unit 12. The incident light can be propagated to the photoelectric conversion unit 12, and light leakage into surrounding pixels can be suppressed.

[0162] 29 and 30, a light guiding wall including a member 94 can guide a portion of the incident light to the photoelectric conversion unit 12. The light guiding wall performs the light collection performance in the Y-axis direction, which is orthogonal to the polarization separation direction (i.e., the X-axis direction), thereby reducing the design load (i.e., the design difficulty) of the metasurface layer. Crosstalk between pixels P can be suppressed.

[0163] 31A, 31B, and 32 are diagrams for explaining a configuration example of an imaging device according to Modification 8. Fig. 31A shows an example of the planar configuration of the optical layer 80, and Fig. 31B shows an example of the planar configuration of the semiconductor layer 10. The optical layer 80 of the imaging device 1 may have three or more types of light-collecting regions.

[0164] The optical layer 80 further includes, for example, a region (referred to as a light-collecting region 83) that collects polarized light L3 (e.g., 45° polarized light) of the incident light, and a region (referred to as a light-collecting region 84) that collects polarized light L4 (e.g., 135° polarized light). In the imaging device 1, the light-collecting regions 81 to 84 adjust the traveling directions of the polarized light L1 to L4, respectively.

[0165] The multiple pixels P of the pixel unit 100 include, for example, pixels P3 and P4 in addition to pixels P1 and P2. As an example, pixel P3 generates a pixel signal with a 45° polarization component, and pixel P4 generates a pixel signal with a 135° polarization component. Pixels P3 and P4 are positioned adjacent to each other in the X-axis direction (or Y-axis direction). In the pixel unit 100, for example, pixels P1, P2, P3, and P4 may be arranged repeatedly.

[0166] 32 , the light-collecting region 83 is provided for the pixel P3. For example, the light-collecting region 83 is provided to correspond to the pixel P3 and a part of the pixel P4 adjacent to the pixel P3. When viewed from above the optical layer 80, the light-collecting region 83 is positioned so as to overlap with the photoelectric conversion unit 12 of the pixel P3 and at least a part of the photoelectric conversion unit 12 of the pixel P4.

[0167] 32 , the light-collecting region 84 is provided for pixel P4. For example, the light-collecting region 84 is provided to correspond to pixel P4 and a part of pixel P3 adjacent to pixel P4. When viewed from above the optical layer 80, the light-collecting region 84 is positioned so as to overlap with the photoelectric conversion unit 12 of pixel P4 and at least a part of the photoelectric conversion unit 12 of pixel P3.

[0168] The optical layer 80 has, for example, a plurality of light-collecting regions 83, the number of which corresponds to the number of pixels P3 in the pixel unit 100. The optical layer 80 also has a plurality of light-collecting regions 84, the number of which corresponds to the number of pixels P4 in the pixel unit 100. The light-collecting regions 83 in the optical layer 80 can be configured as regions that overlap with parts of the light-collecting regions 84.

[0169] For example, the light collection region 83 overlaps with a portion of the light collection region 84 and includes a portion of the light collection region 84. Furthermore, the light collection region 84 overlaps with a portion of the light collection region 83 and includes a portion of the light collection region 83. The light collection region 83 and the light collection region 84 partially overlap each other. The light collection region 83 and the light collection region 84 are regions that overlap each other, and can also be said to be provided so as to overlap each other.

[0170] The light collecting region 83 and the light collecting region 84 may each have a light receiving area larger than the area of ​​one pixel P, for example, a light receiving area that is approximately twice the area of ​​one pixel P. For example, in a plan view (i.e., when viewed on the XY plane), the light receiving area of ​​each of the light collecting region 83 and the light collecting region 84 is twice the area of ​​the pixel P.

[0171] The optical layer 80 is configured so that the center position of the light collection region 83 is different from the center position of the light collection region 84. In a direction (e.g., the X-axis direction) perpendicular to the stacking direction (Z-axis direction) of the optical layer 80 and the semiconductor layer 10, the center position of the light collection region 83 is different from the center position of the light collection region 84. In the example shown in Fig. 32 , the center of the light collection region 83 is located apart from the center of the light collection region 84 in the horizontal direction (X-axis direction).

[0172] The imaging device 1 can obtain, for example, a pixel signal of a 90° polarization component, a pixel signal of a 0° polarization component, a pixel signal of a 45° polarization component, and a pixel signal of a 135° polarization component using pixels P1 to P4. Stokes parameters can be calculated using the four types of polarization information, making it possible to visualize the polarization information.

[0173] For example, the imaging device 1 may be configured so that the center of the light-collecting region 83 and the center of the pixel P3 are located on the same axis. The imaging device 1 may also be configured so that the center of the light-collecting region 84 and the center of the pixel P4 are located on the same axis. The optical layer 80 of the imaging device 1 may be configured to include only one, two, or three of the light-collecting regions 81 to 84.

[0174] 33 and 34 are diagrams illustrating a configuration example of an imaging device according to Modification 9. The imaging device 1 may include a polarizer 25 (polarizer 25a and polarizer 25b in FIGS. 33 and 34). The polarizer 25 is configured to selectively transmit a specific polarization component of incident light. The polarizer 25 is provided above the photoelectric conversion unit 12, for example, for each pixel P or for each set of pixels P (i.e., for each predetermined number of pixels P).

[0175] The polarizer 25 is configured using, for example, a member 28 made of a metal material and a member 29 made of a dielectric material. The polarizer 25 includes the member 29 as a dielectric wire and is configured as a wire-gird type polarizer. The polarizer 25 may also be a photonic crystal type polarizer.

[0176] 33 , the polarizers 25a and 25b are provided in the spacer layer 90 between the optical layer 80 and the semiconductor layer 10. The polarizer 25a is provided between the optical layer 80 and the photoelectric conversion unit 12 of the pixel P1 and is configured to transmit polarized light L1. The polarizer 25b is provided between the optical layer 80 and the photoelectric conversion unit 12 of the pixel P2 and is configured to transmit polarized light L2.

[0177] In the imaging device 1 according to this modification, the provision of the polarizer 25 can suppress crosstalk between the pixels P. This can suppress the mixing of noise into pixel signals, and can suppress degradation in the image quality of an image generated using the pixel signals, for example.

[0178] 35A and 35B are diagrams illustrating an example configuration of an imaging device according to Modification 10. A pixel P may have a rectangular shape. In the example shown in FIGS. 35A and 35B , the aspect ratio of the pixel P in the X and Y directions is 1:2. The length of a side of the pixel P in the Y direction may be twice the length of the side of the pixel P in the X direction.

[0179] 35A , the light collection region 81 and the light collection region 82 of the optical layer 80 may have a shape corresponding to the shape of the pixel P. By configuring the imaging device 1 in this manner, it is possible to make the aspect ratio of the spot (i.e., the light collection spot) formed by the light collection region 81 (or the light collection region 82) approach 1:1.

[0180] 2. Second Embodiment Next, a second embodiment of the present disclosure will be described. The technology according to the present disclosure is applicable to various electronic devices, optical devices, etc. The optical layer 80 configured using the above-described nanostructures is applicable to various optical elements (optical members). In the following, components similar to those in the above-described embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0181] 36 and 37 are diagrams illustrating a configuration example of an optical element according to the second embodiment of the present disclosure. The optical element 200 includes a substrate 120 and an optical layer 80. As an example, the optical layer 80 includes a structure 71 and a member 75 provided around the structure 71. The optical element 200 is an optical element (optical member) configured using the structure 71, which is a nanostructure, and can be configured as a metalens (metamaterial lens).

[0182] The substrate 120 is a substrate (transparent substrate) that transmits light, and is made of, for example, a glass substrate. As an example, the substrate 120 (base material) can be made of a material having a refractive index lower than that of the structure 71. The substrate 120 may be made of, for example, quartz glass, borosilicate glass, or the like, or may be made of a resin substrate. The substrate 120 may also be made of another material that transmits the light to be measured.

[0183] As shown in Fig. 36 , the substrate 120 has opposing surfaces 12S1 and 12S2. The surface 12S2 is the surface opposite to the surface 12S1. The optical layer 80 is provided, for example, on the light-incident side of the substrate 120. In the example shown in Fig. 36 , the optical layer 80 including a plurality of structures 71 is formed on the surface 12S1 of the substrate 120.

[0184] The optical layer 80 including the structures 71 may be provided on the side of the substrate 120 opposite to the side where light is incident (i.e., the side where light is emitted). The optical layer 80 may be laminated on the substrate 120 via an insulating layer on the light incident side or the light exit side of the substrate 120. The shape of the substrate 120 is not particularly limited, and may be circular, rectangular, or another shape. The shape, number, arrangement, etc. of the structures 71 are not limited to the example shown in the figure, and can be changed as appropriate.

[0185] The optical element 200 is configured, for example, as a polarization separation lens that can separate polarized light from incident light. The optical element 200 can also be called a polarization separation element (i.e., a metasurface polarization separation element). The optical element 200 can selectively separate and focus predetermined polarization components contained in incident light. The optical element 200 may be configured, for example, as part of the optical system of various devices.

[0186] 37 , the optical layer 80 has a region (light-collecting region 81) that collects polarized light L1 (e.g., 90° polarized light) of the incident light, and a region (light-collecting region 82) that collects polarized light L2 (e.g., 0° polarized light). The light-collecting region 81 and the light-collecting region 82 adjust the traveling directions of the polarized light L1 and the polarized light L2, respectively.

[0187] The optical element 200 can collect polarized light L1 using the light-collecting region 81 and collect polarized light L2 using the light-collecting region 82. Note that the polarized light L1 and polarized light L2 guided by the optical layer 80 may each be other polarization components (e.g., 45° polarization, 135° polarization, etc.). The configurations of the optical element 200 and the optical layer 80 are not limited to the example shown in the figure, and can be changed as appropriate, similar to the first embodiment described above.

[0188] For example, the optical element 200 may have an antireflection film 45 (antireflection film 45a, antireflection film 45b, etc.). The optical layer 80 may have a multi-layer (multi-stage) structure 71. For example, as shown in the example in Fig. 38 , the optical layer 80 may have a structure 71a and a structure 71b. The optical layer 80 may have three or more types of light-collecting regions.

[0189] [Actions and Effects] The optical element according to this embodiment includes a substrate (substrate 120) and an optical layer (optical layer 80) having a plurality of first structures (structures 71) and stacked on the substrate. The optical layer has a first region and a second region (e.g., light-collecting region 81, light-collecting region 82). The center position of the first region is different from the center position of the second region. The optical layer is capable of collecting first polarized light (e.g., polarized light L1) incident on the first region, and is capable of collecting second polarized light (e.g., polarized light L2) different from the first polarized light incident on the second region.

[0190] In the optical element (optical element 200) according to this embodiment, the optical layer 80 has a light-collecting region 81 and a light-collecting region 82. The center position of the light-collecting region 81 is different from the center position of the light-collecting region 82. In this embodiment, incident light can be efficiently collected. It is possible to realize an optical element that can efficiently collect light.

[0191] 3. Application Examples The imaging device 1 and the like can be applied to any type of electronic device equipped with an imaging function, for example, a camera system such as a digital still camera or video camera, a mobile phone with an imaging function, etc. Fig. 39 shows a schematic configuration of an electronic device 1000.

[0192] The electronic device 1000 includes, for example, a lens group 1001, an imaging device 1, a DSP (Digital Signal Processor) circuit 1002, a frame memory 1003, a display unit 1004, a recording unit 1005, an operation unit 1006, and a power supply unit 1007, which are interconnected via a bus line 1008.

[0193] The lens group 1001 captures incident light (image light) from a subject and forms an image on the imaging surface of the imaging device 1. The imaging device 1 converts the amount of incident light formed on the imaging surface by the lens group 1001 into an electrical signal on a pixel-by-pixel basis and supplies the signal as a pixel signal to the DSP circuit 1002.

[0194] The DSP circuit 1002 is a signal processing circuit that processes signals supplied from the imaging device 1. The DSP circuit 1002 outputs image data obtained by processing the signals from the imaging device 1. The frame memory 1003 temporarily stores the image data processed by the DSP circuit 1002 on a frame-by-frame basis.

[0195] The display unit 1004 is composed of a panel-type display device such as a liquid crystal panel or an organic EL (Electro Luminescence) panel, and records image data of moving images or still images captured by the imaging device 1 on a recording medium such as a semiconductor memory or a hard disk.

[0196] The operation unit 1006, in response to a user's operation, outputs operation signals for various functions of the electronic device 1000. The power supply unit 1007 supplies various types of power to the DSP circuit 1002, frame memory 1003, display unit 1004, recording unit 1005, and operation unit 1006 as needed.

[0197] 4. Application Examples (Application Examples to Mobile Bodies) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0198] FIG. 40 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0199] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 40, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (Interface) 12053.

[0200] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0201] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0202] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0203] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0204] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0205] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the distance between vehicles, maintaining vehicle speed, vehicle collision warning, vehicle lane departure warning, etc.

[0206] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0207] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0208] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying the passengers of the vehicle or the outside of the vehicle of information. In the example of Fig. 40, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0209] FIG. 41 is a diagram showing an example of the installation position of the imaging unit 12031.

[0210] In FIG. 41, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0211] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0212] 41 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0213] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0214] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation.

[0215] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0216] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0217] An example of a mobile object control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the image capturing unit 12031 of the above-described configuration. Specifically, for example, the image capturing device 1 and the optical element 200 can be applied to the image capturing unit 12031. By applying the technology according to the present disclosure to the image capturing unit 12031, it becomes possible to obtain a high-resolution captured image. It becomes possible to perform high-precision control using the captured image in the mobile object control system.

[0218] (Application Example to Endoscopic Surgery System) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0219] FIG. 42 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0220] 42 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0221] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the example shown, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible scope having a flexible lens barrel.

[0222] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0223] An optical system and an image sensor are provided inside the camera head 11102, and light reflected from the object of observation (observation light) is collected by the optical system onto the image sensor. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to a camera control unit (CCU) 11201 as RAW data.

[0224] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and comprehensively controls the operations of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102 and performs various types of image processing on the image signal, such as development processing (demosaic processing), to display an image based on the image signal.

[0225] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0226] The light source device 11203 is composed of a light source such as an LED (Light Emitting Diode), and supplies the endoscope 11100 with irradiation light when photographing the surgical site, etc.

[0227] The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) of the endoscope 11100.

[0228] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 inflates the body cavity of the patient 11132 through the insufflation tube 11111 in order to ensure a clear field of view for the endoscope 11100 and a working space for the surgeon. The recorder 11207 is a device capable of recording various types of information related to the surgery. The printer 11208 is a device capable of printing various types of information related to the surgery in various formats such as text, images, or graphs.

[0229] The light source device 11203, which supplies illumination light to the endoscope 11100 when photographing the surgical site, can be configured from a white light source, such as an LED, a laser light source, or a combination of these. When the white light source is configured from a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, allowing the light source device 11203 to adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each RGB by irradiating the object of observation with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, color images can be obtained without providing a color filter to the image sensor.

[0230] Furthermore, the light source device 11203 may be controlled to change the intensity of light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity to acquire images in a time-division manner and combining the images, it is possible to generate an image with a high dynamic range that is free from so-called blocked-up shadows and blown-out highlights.

[0231] The light source device 11203 may also be configured to supply light in a predetermined wavelength band corresponding to special light observation. Special light observation, for example, utilizes the wavelength dependence of light absorption in body tissues to irradiate light in a narrower band than the light irradiated during normal observation (i.e., white light) to capture high-contrast images of specific tissues, such as blood vessels on the surface of mucous membranes, in what is known as narrow band imaging. Alternatively, special light observation may involve fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light. Fluorescence observation may involve irradiating excitation light onto body tissues and observing the fluorescence from the tissues (autofluorescence observation), or may involve locally injecting a reagent such as indocyanine green (ICG) into the body tissue and irradiating the tissues with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow band light and / or excitation light corresponding to such special light observation.

[0232] FIG. 43 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0233] The camera head 11102 has a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with each other.

[0234] The lens unit 11401 is an optical system provided at the connection portion with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses including a zoom lens and a focus lens.

[0235] The imaging unit 11402 is composed of an imaging element. The imaging element constituting the imaging unit 11402 may be a single (so-called single-chip type) or multiple (so-called multi-chip type). When the imaging unit 11402 is composed of a multi-chip type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining these signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to 3D (dimensional) display. The 3D display allows the surgeon 11131 to more accurately grasp the depth of the biological tissue at the surgical site. Note that when the imaging unit 11402 is composed of a multi-chip type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0236] Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens barrel 11101, immediately after the objective lens.

[0237] The driving unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted appropriately.

[0238] The communication unit 11404 is configured by a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0239] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201 and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of imaging, and / or information specifying the magnification and focus of the captured image.

[0240] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0241] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404 .

[0242] The communication unit 11411 is configured by a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0243] Furthermore, the communication unit 11411 transmits to the camera head 11102 a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0244] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0245] The control unit 11413 performs various controls related to the imaging of the surgical site, etc. by the endoscope 11100 and the display of the captured image obtained by imaging the surgical site, etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0246] Furthermore, the control unit 11413 displays the captured image showing the surgical site, etc., on the display device 11202 based on the image signal subjected to image processing by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition technologies. For example, the control unit 11413 can recognize surgical tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition results to superimpose various surgical support information on the image of the surgical site. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0247] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable of these.

[0248] In the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0249] The above describes an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. Of the above-described configurations, the technology according to the present disclosure can be suitably applied to, for example, the imaging unit 11402 provided in the camera head 11102 of the endoscope 11100. By applying the technology according to the present disclosure to the imaging unit 11402, it is possible to provide a high-definition endoscope 11100.

[0250] Although the present disclosure has been described above by way of embodiments, modifications, application examples, and applied examples, the present technology is not limited to the above-described embodiments, etc., and various modifications are possible. For example, although the modifications described above have been described as modifications of the above-described embodiments, the configurations of the modifications can be combined as appropriate.

[0251] In the above embodiments, an imaging device has been described as an example. However, the photodetector of the present disclosure may be, for example, a device that receives incident light and converts the light into an electric charge. The output signal may be a signal of image information or a signal of ranging information. The photodetector (imaging device) may be applied to an image sensor, a ranging sensor, etc. Note that the present disclosure is not limited to a back-illuminated image sensor, but may also be applied to a front-illuminated image sensor.

[0252] The photodetector according to the present disclosure may also be applied as a distance measuring sensor capable of measuring distances using a time-of-flight (TOF) method. The light receiving element (photoelectric conversion unit) of each pixel may be an avalanche photodiode (APD). The light receiving element may be configured, for example, by a single-photon avalanche diode (SPAD). The photodetector (image capture device) may also be applied as a sensor capable of detecting events, for example, an event-driven sensor (also known as an event vision sensor (EVS), event-driven sensor (EDS), dynamic vision sensor (DVS), etc.).

[0253] An optical element according to an embodiment of the present disclosure includes a substrate and an optical layer having a plurality of first structures and stacked on the substrate. The optical layer has a first region and a second region. The center position of the first region is different from the center position of the second region. The optical layer is capable of focusing first polarized light incident on the first region and is capable of focusing second polarized light, different from the first polarized light, incident on the second region. This makes it possible to realize an optical element capable of focusing light efficiently.

[0254] According to one embodiment of the present disclosure, a photodetector includes a semiconductor layer, a first photoelectric conversion region and a second photoelectric conversion region provided in the semiconductor layer, and an optical layer provided above the semiconductor layer and having a plurality of first structures. The optical layer includes a first region corresponding to the first photoelectric conversion region and a second region corresponding to the second photoelectric conversion region. The center position of the first region is different from the center position of the second region. The optical layer guides first polarized light incident on the first region to the first photoelectric conversion region and guides second polarized light, different from the first polarized light incident on the second region, to the second photoelectric conversion region. This makes it possible to realize a photodetector capable of efficiently collecting light.

[0255] Note that the effects described in this specification are merely examples and are not limited to those described above, and other effects may be present. The present disclosure may also have the following configurations. (1) An optical element comprising: a substrate; and an optical layer having a plurality of first structures and stacked on the substrate, wherein the optical layer has a first region and a second region, the center position of the first region being different from the center position of the second region, and the optical layer being capable of focusing first polarized light incident on the first region and second polarized light incident on the second region, the second polarized light being different from the first polarized light. (2) The optical element described in (1), wherein the plurality of first structures are arranged in the optical layer in a first direction, and the first region and the second region partially overlap each other in the first direction. (3) The optical element described in (1) or (2), wherein the optical layer is capable of focusing the first polarized light incident on the first region and the second polarized light incident on the second region in different regions. (4) The optical element according to any one of (1) to (3), wherein the first polarized light and the second polarized light are linearly polarized light that are orthogonal to each other, and the optical layer is capable of focusing light polarized at an angle of 0°, 45°, 90°, or 135° as the first polarized light. (5) The optical element according to any one of (1) to (4), wherein the optical layer has a member provided around the first structures, and the first structures have a refractive index different from that of the member. (6) The optical element according to any one of (1) to (5), wherein the optical layer has a first layer including the plurality of first structures, and a second layer including a plurality of second structures and provided so as to be stacked on the first layer. (7) A photodetector comprising: a semiconductor layer; a first photoelectric conversion region and a second photoelectric conversion region provided in the semiconductor layer; and an optical layer provided above the semiconductor layer and having a plurality of first structures, wherein the optical layer includes a first region corresponding to the first photoelectric conversion region and a second region corresponding to the second photoelectric conversion region, the center position of the first region being different from the center position of the second region, and the optical layer guiding a first polarized light incident on the first region to the first photoelectric conversion region and guiding a second polarized light incident on the second region, different from the first polarized light, to the second photoelectric conversion region.(8) The photodetector according to (7), wherein the plurality of first structures are arranged in the optical layer so as to be aligned in a first direction, and the first region and the second region partially overlap each other in the first direction. (9) The photodetector according to (7) or (8), wherein the optical layer focuses the first polarized light incident on the first region to the first photoelectric conversion region and focuses the second polarized light incident on the second region to the second photoelectric conversion region. (10) The photodetector according to any one of (7) to (9), comprising: a first pixel having the first photoelectric conversion region; and a second pixel having the second photoelectric conversion region, wherein the center of the first region and the center of the first pixel are positioned on the same axis. (11) The photodetector according to (10), wherein the center of the second region and the center of the second pixel are positioned on the same axis. (12) The photodetector according to (10) or (11), wherein some of the plurality of first structures are provided at the boundary between the first pixel and the second pixel, and the shape of the first structure provided at the boundary between the first pixel and the second pixel has rotational symmetry. (13) The photodetector according to any one of (7) to (12), wherein the first structures have a columnar shape. (14) The photodetector according to any one of (7) to (13), further including a spacer layer provided between the optical layer and the semiconductor layer. (15) The photodetector according to (14), wherein the spacer layer has a first member and a second member having a refractive index lower than that of the first member, and the second member is provided to sandwich the first member in a direction perpendicular to a thickness direction of the spacer layer. (16) The photodetector according to (15), comprising: a first pixel having the first photoelectric conversion region; and a second pixel having the second photoelectric conversion region, wherein at least a portion of the second member is provided at a boundary between the first pixel and the second pixel. (17) The photodetector according to (15) or (16), wherein the second member is provided so as to surround the first member in a direction perpendicular to a thickness direction of the spacer layer.(18) The photodetector according to any one of (7) to (17), further including a third photoelectric conversion region and a fourth photoelectric conversion region provided in the semiconductor layer, wherein the optical layer includes a third region corresponding to the third photoelectric conversion region and a fourth region corresponding to the fourth photoelectric conversion region, a center position of the third region being different from a center position of the fourth region, and the optical layer directing third polarized light incident on the third region to the third photoelectric conversion region and directing fourth polarized light incident on the fourth region, different from the third polarized light, to the fourth photoelectric conversion region. (19) The photodetector according to any one of (7) to (18), further including: a first polarizer provided between the optical layer and the first photoelectric conversion region and transmitting the first polarized light; and a second polarizer provided between the optical layer and the second photoelectric conversion region and transmitting the second polarized light. (20) An electronic device comprising: an optical system; and a photodetector that receives light transmitted through the optical system, wherein the photodetector has: a semiconductor layer; a first photoelectric conversion region and a second photoelectric conversion region provided in the semiconductor layer; and an optical layer provided above the semiconductor layer and having a plurality of first structures, wherein the optical layer includes a first region corresponding to the first photoelectric conversion region and a second region corresponding to the second photoelectric conversion region, wherein a center position of the first region is different from a center position of the second region, and wherein the optical layer guides a first polarized light incident on the first region to the first photoelectric conversion region and guides a second polarized light incident on the second region, different from the first polarized light, to the second photoelectric conversion region.

[0256] This application claims priority based on Japanese Patent Application No. 2024-148612, filed on August 30, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0257] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. An optical element comprising: a substrate; and an optical layer having a plurality of first structures and stacked on the substrate, wherein the optical layer has a first region and a second region, the central position of the first region is different from the central position of the second region, and the optical layer is capable of focusing a first polarized light incident on the first region, and is capable of focusing a second polarized light, different from the first polarized light, incident on the second region.

2. The optical element according to claim 1, wherein the plurality of first structures are arranged in the optical layer so as to be aligned in a first direction, and the first region and the second region partially overlap each other in the first direction.

3. The optical element according to claim 1, wherein the optical layer is capable of focusing the first polarized light incident on the first region and the second polarized light incident on the second region onto different regions.

4. The optical element according to claim 1, wherein the first polarized light and the second polarized light are linearly polarized light that are orthogonal to each other, and the optical layer is capable of focusing 0°, 45°, 90°, or 135° polarized light as the first polarized light.

5. The optical element according to claim 1, wherein the optical layer has a member provided around the first structure, and the first structure has a refractive index different from that of the member.

6. The optical element according to claim 1, wherein the optical layer comprises a first layer including the plurality of first structures, and a second layer including a plurality of second structures and disposed so as to be stacked with the first layer.

7. A photodetector comprising: a semiconductor layer; a first photoelectric conversion region and a second photoelectric conversion region provided in the semiconductor layer; and an optical layer provided above the semiconductor layer and having a plurality of first structures, wherein the optical layer includes a first region corresponding to the first photoelectric conversion region and a second region corresponding to the second photoelectric conversion region, the center position of the first region differs from the center position of the second region, and the optical layer guides first polarized light incident on the first region to the first photoelectric conversion region, and guides second polarized light incident on the second region, different from the first polarized light, to the second photoelectric conversion region.

8. The photodetector device according to claim 7, wherein a plurality of the first structures are arranged in the optical layer so as to be aligned in a first direction, and the first region and the second region partially overlap each other in the first direction.

9. The photodetector device of claim 7, wherein the optical layer focuses the first polarized light incident on the first region onto the first photoelectric conversion region, and focuses the second polarized light incident on the second region onto the second photoelectric conversion region.

10. A photodetector device as described in claim 7, comprising a first pixel having the first photoelectric conversion region and a second pixel having the second photoelectric conversion region, wherein the center of the first region and the center of the first pixel are located on the same axis.

11. The photodetector device according to claim 10, wherein the center of said second region and the center of said second pixel are located on the same axis.

12. The photodetector device according to claim 10, wherein some of the plurality of first structures are provided at the boundary between the first pixel and the second pixel, and the shape of the first structures provided at the boundary between the first pixel and the second pixel has rotational symmetry.

13. The photodetector according to claim 7, wherein the first structure has a columnar shape.

14. The photodetector device of claim 7, further comprising a spacer layer disposed between the optical layer and the semiconductor layer.

15. The optical detection device described in claim 14, wherein the spacer layer has a first member and a second member having a refractive index lower than that of the first member, and the second member is arranged to sandwich the first member in a direction perpendicular to the thickness direction of the spacer layer.

16. A photodetector according to claim 15, comprising: a first pixel having the first photoelectric conversion region; and a second pixel having the second photoelectric conversion region, wherein at least a portion of the second member is provided at the boundary between the first pixel and the second pixel.

17. The photodetector according to claim 15, wherein the second member is provided so as to surround the first member in a direction perpendicular to the thickness direction of the spacer layer.

18. The photodetector device of claim 7, further comprising a third photoelectric conversion region and a fourth photoelectric conversion region provided in the semiconductor layer, wherein the optical layer includes a third region corresponding to the third photoelectric conversion region and a fourth region corresponding to the fourth photoelectric conversion region, the center position of the third region being different from the center position of the fourth region, and the optical layer guiding third polarized light incident on the third region to the third photoelectric conversion region and guiding fourth polarized light incident on the fourth region, different from the third polarized light, to the fourth photoelectric conversion region.

19. The photodetector device of claim 7, further comprising: a first polarizer disposed between the optical layer and the first photoelectric conversion region and transmitting the first polarized light; and a second polarizer disposed between the optical layer and the second photoelectric conversion region and transmitting the second polarized light.

20. An electronic device comprising: an optical system; and a photodetector that receives light that has passed through the optical system, wherein the photodetector has: a semiconductor layer; a first photoelectric conversion region and a second photoelectric conversion region provided in the semiconductor layer; and an optical layer provided above the semiconductor layer and having a plurality of first structures, wherein the optical layer includes a first region corresponding to the first photoelectric conversion region and a second region corresponding to the second photoelectric conversion region, wherein the center position of the first region is different from the center position of the second region, and wherein the optical layer guides first polarized light that is incident on the first region to the first photoelectric conversion region, and guides second polarized light that is different from the first polarized light that is incident on the second region to the second photoelectric conversion region.

Images