Light detection device, optical element, and electronic device

Abstract

A light detection device according to one embodiment of the present disclosure comprises: a first layer that includes a first material layer to which a first structure having a columnar shape is provided; and a photoelectric conversion element that carries out photoelectric conversion of light which is incident via the first layer. The first structure includes a first member that is provided to the first material layer, and a second member that is provided inside the first member and that has a refractive index which is different from the refractive index of the first member.

Description

Photodetector, optical element, and electronic device

[0001] The present disclosure relates to a light detection device, an optical element, and an electronic device.

[0002] An image sensor has been proposed that includes a pattern structure as a splitter and a filler layer pattern provided on both sides of the splitter (Patent Document 1).

[0003] US Patent Application Publication No. 2019 / 0157336

[0004] Light-detecting devices are required to minimize degradation of quality.

[0005] It is desirable to provide a photodetector that can suppress deterioration in quality.

[0006] A photodetector according to an embodiment of the present disclosure includes a first layer including a first material layer on which first structures having a columnar shape are provided, and a photoelectric conversion element that performs photoelectric conversion on light incident through the first layer. The first structures include a first member provided in the first material layer and a second member provided within the first member and having a refractive index different from that of the first member. An optical element according to an embodiment of the present disclosure includes a first material layer and a first structure provided in the first material layer and having a columnar shape. The first structure includes a first member provided in the first material layer and a second member provided within the first member and having a refractive index different from that of the first member. An electronic device according to an embodiment of the present disclosure includes an optical system and a photodetector that receives light transmitted through the optical system. The photodetector includes a first layer including a first material layer on which first structures having a columnar shape are provided, and a photoelectric conversion element that performs photoelectric conversion on light incident through the first layer. The first structure includes a first member provided in the first material layer, and a second member provided within the first member and having a refractive index different from that of the first member.

[0007] FIG. 1 is a block diagram illustrating an example of a schematic configuration of an imaging device that is an example of a photodetector according to a first embodiment of the present disclosure. FIG. 2 is a diagram illustrating an example of a pixel unit of the imaging device according to the first embodiment of the present disclosure. FIG. 3 is a diagram for explaining an example of a circuit configuration of a pixel of the imaging device according to the first embodiment of the present disclosure. FIG. 4 is a diagram illustrating an example of a planar configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 5 is a diagram illustrating an example of a cross-sectional configuration of the imaging device according to the first embodiment of the present disclosure. FIG. 6A is a diagram for explaining an example of a method for manufacturing a light guiding section of the imaging device according to the first embodiment of the present disclosure. FIG. 6B is a diagram for explaining an example of a method for manufacturing a light guiding section of the imaging device according to the first embodiment of the present disclosure. FIG. 6C is a diagram for explaining an example of a method for manufacturing a light guiding section of the imaging device according to the first embodiment of the present disclosure. FIG. 6D is a diagram for explaining an example of a method for manufacturing a light guiding section of the imaging device according to the first embodiment of the present disclosure. FIG. 6E is a diagram for explaining an example of a method for manufacturing a light guiding section 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 an imaging device according to a first modification of the present disclosure. FIG. 8A is a diagram for describing an example of a method for manufacturing a light guiding section of an imaging device according to Modification 1 of the present disclosure. FIG. 8B is a diagram for describing an example of a method for manufacturing a light guiding section of an imaging device according to Modification 1 of the present disclosure. FIG. 8C is a diagram for describing an example of a method for manufacturing a light guiding section of an imaging device according to Modification 1 of the present disclosure. FIG. 8D is a diagram for describing an example of a method for manufacturing a light guiding section of an imaging device according to Modification 1 of the present disclosure. FIG. 8E is a diagram for describing an example of a method for manufacturing a light guiding section of an imaging device according to Modification 1 of the present disclosure. FIG. 8F is a diagram for describing an example of a method for manufacturing a light guiding section of an imaging device according to Modification 1 of the present disclosure. FIG. 9 is a diagram for describing an example configuration of an imaging device according to Modification 2 of the present disclosure. FIG. 10 is a diagram for describing another example configuration of an imaging device according to Modification 2 of the present disclosure. FIG. 11A is a diagram for describing an example configuration of a light guiding section of an imaging device according to Modification 3 of the present disclosure. FIG. 11B is a diagram for describing an example configuration of a light guiding section of an imaging device according to Modification 3 of the present disclosure. FIG. 12 is a diagram for describing an example configuration of an imaging device according to Modification 4 of the present disclosure. FIG. 13 is a diagram illustrating an example of the configuration of an imaging device according to the fifth modification of the present disclosure.FIG. 14 is a diagram for explaining a configuration example of an imaging device according to Modification 5 of the present disclosure. FIG. 15 is a diagram for explaining a configuration example of an imaging device according to Modification 6 of the present disclosure. FIG. 16 is a diagram for explaining a configuration example of an optical element according to a second embodiment of the present disclosure. FIG. 17 is a block diagram showing a configuration example of an electronic device having an imaging device. FIG. 18 is a block diagram showing an example of a schematic configuration of a vehicle control system. FIG. 19 is an explanatory diagram showing an example of installation positions of an outside-vehicle information detection unit and an imaging unit. FIG. 20 is a diagram showing an example of a schematic configuration of an endoscopic surgery system. FIG. 21 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 a photodetection device has a plurality of pixels P each having a photoelectric conversion unit (photoelectric conversion element), and is configured to photoelectrically convert incident light to generate a signal.

[0010] The imaging device 1 can generate a signal by receiving light that has passed through an optical system (not shown) including an optical lens. The imaging device 1 is configured, for example, using a semiconductor substrate (e.g., a silicon substrate) on which a plurality of pixels P are provided. The photoelectric conversion unit of each pixel P of the imaging device 1 is, for example, a photodiode (PD) that is configured to be able to photoelectrically convert light.

[0011] 1 and 2, the imaging device 1 has, as an imaging area, a region (pixel section 100) in which a plurality of pixels P are arranged two-dimensionally in a matrix. The pixel section 100 of the imaging device 1 is a pixel array in which a plurality of pixels P are arranged, and can also be referred to as a light receiving region. The photoelectric conversion section of each pixel P can also be referred to as a photoelectric conversion region.

[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 incident light and generate a signal, and can also be called a light-receiving device.

[0013] 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. The imaging device 1 may have a structure (a stacked structure) formed by stacking multiple semiconductor layers. The imaging device 1 may be used in various electronic devices, such as digital still cameras, video cameras, and mobile phones.

[0014] 2, the incident direction of light from the subject is defined as the Z-axis direction, the left-right direction on the paper surface perpendicular to the Z-axis direction is defined as the X-axis direction, and the up-down direction on the paper surface perpendicular to the Z-axis and X-axis directions is defined as the Y-axis direction. In the following figures, directions may be indicated based on the direction of the arrow in FIG. 2.

[0015] 1, the imaging device 1 includes, for example, 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 L1 and a plurality of signal lines L2.

[0016] The control lines L1 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 , in the pixel unit 100, a plurality of control lines L1 are wired for each pixel row made up of a plurality of pixels P arranged in the horizontal direction (row direction). The control lines L1 are configured to transmit control signals for reading out signals from the pixels P.

[0017] The plurality of control lines L1 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 L1 can also be referred to as drive lines (pixel drive lines) that transmit signals that drive the pixels P.

[0018] The signal line L2 is a signal line capable of transmitting a signal from the pixel P, and is connected to the pixel P of the pixel unit 100 and the signal processing unit 112. In the pixel unit 100, for example, one or more signal lines L2 are wired for each pixel column made up of multiple pixels P lined up in the vertical direction (column direction). The signal line L2 is configured to be able to transmit a signal output from the pixel P. In the imaging device 1, multiple signal lines L2 may be provided for one pixel column. The imaging device 1 may have multiple signal lines L2 for each pixel column.

[0019] 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 a signal for controlling the pixel P and outputs it to each pixel P of the pixel unit 100 via a control line L1. The pixel control unit 111 is controlled by the control unit 113 and controls the pixels P of the pixel unit 100.

[0020] The pixel control unit 111 generates signals for controlling the pixels P, such as signals for controlling the transfer transistors, selection transistors, and reset transistors of the pixels P, and supplies these signals to each pixel P via a control line L1. The pixel control unit 111 can control the reading of pixel signals from each pixel P. The pixel control unit 111 can also be referred to as a pixel driving unit configured to be able to drive each pixel P. The pixel control unit 111 and the control unit 113 can also be referred to collectively as a pixel control unit.

[0021] 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, for example, configured by a current source capable of supplying current to the amplification transistor of the pixel P. The load circuit, together with the amplification transistor of the pixel P, forms, for example, a source follower circuit.

[0022] The signal processing unit 112 may have an amplifier circuit configured to be able to amplify signals read out from the pixels P via the signal lines L2. A load circuit, an amplifier circuit, an AD conversion circuit, etc. may be provided for each of the multiple signal lines L2, for example. A load circuit, an amplifier circuit, an AD conversion circuit, etc. may be provided for each pixel column of the pixel unit 100.

[0023] 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 a signal line L2. The signal processing unit 112 can perform signal processing such as AD conversion of the signal from the pixel P and CDS (Correlated Double Sampling). The signals from each pixel P transmitted through each signal line L2 are subjected to signal processing by the signal processing unit 112 and output to the processing unit 114.

[0024] The processing unit 114 is configured to be able to perform signal processing on the input signal. The processing unit 114 is a processing circuit, and is configured, for example, by a circuit that performs various types of signal processing on pixel signals. The processing unit 114 may include a processor and a memory. The processing unit 114 performs signal processing on pixel signals input from the signal processing unit 112 and outputs the processed pixel signals. The processing unit 114 can perform various types of signal processing, for example, noise reduction processing, gradation correction processing, etc.

[0025] 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.

[0026] 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 and the processing unit 114 may be configured integrally.

[0027] The pixel unit 100, the pixel control unit 111, the signal processing unit 112, etc. described above may be provided on a single substrate. The pixel control unit 111, the signal processing unit 112, the control unit 113, the processing unit 114, etc. may be provided on a single semiconductor substrate, or may be provided separately on multiple semiconductor substrates. The imaging device 1 may have a stacked structure formed by stacking multiple substrates. Note that some or all of the signal processing unit 112, the control unit 113, and the processing unit 114 may be configured integrally.

[0028] 3 is a diagram illustrating an example of the circuit configuration of a pixel of the imaging device according to the first embodiment. The pixel P includes 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 readout circuit 20 is configured to be able to output a signal based on the charge generated by photoelectric conversion.

[0029] The photoelectric conversion unit 12 is a light receiving unit (light receiving element) configured to be able to generate electric charges by photoelectric conversion. In the example shown in Fig. 3, the photoelectric conversion unit 12 is a photodiode (PD) that converts incident light into electric charges. The photoelectric conversion unit 12 can perform photoelectric conversion to generate electric charges according to the amount of received light.

[0030] The readout circuit 20 includes, for example, a transistor TRG, a floating diffusion FD, a transistor AMP, a transistor SEL, and a transistor RST. The readout circuit 20 can read out pixel signals based on charges photoelectrically converted by the photoelectric conversion unit 12.

[0031] The transistor TRG is a transfer transistor and is configured to be able to transfer charges photoelectrically converted in the photoelectric conversion unit 12 to the floating diffusion FD. The transistor TRG is controlled by a signal STRG to electrically connect or disconnect the photoelectric conversion unit 12 and the floating diffusion FD. The transistor TRG can transfer charges photoelectrically converted and accumulated in the photoelectric conversion unit 12 to the floating diffusion FD.

[0032] 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 can also be considered a holding unit capable of holding the transferred charges. The floating diffusion FD accumulates the transferred charges and converts them into a voltage according to the capacitance of the floating diffusion FD.

[0033] 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 and can generate and output a signal based on the charge converted by the photoelectric conversion unit 12.

[0034] 3, 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. 3).

[0035] The source of the transistor AMP is connected to a signal line L2 via 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 L2.

[0036] 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. 3. 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 L2. The transistor SEL is a selection transistor and can control the output timing of the pixel signal.

[0037] 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 a signal line L2. The transistor SEL may be electrically connected in series between the transistor AMP and a power supply line to which the power supply voltage VDD is applied. The transistor SEL may also be omitted as necessary.

[0038] The transistor RST is configured to be able to reset the voltage of the floating diffusion FD. In the example shown in Fig. 3, the transistor RST is electrically connected to a power supply line to which a power supply voltage VDD is applied, and is configured to reset the charge of the pixel P. The transistor RST is a reset transistor.

[0039] 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 also discharge the charge accumulated in the photoelectric conversion unit 12 via the transistor TRG.

[0040] The readout circuit 20 may be configured to change the conversion efficiency (gain) when converting electric charge into voltage. For example, the readout circuit 20 may include a transistor (switching transistor) used to set the conversion efficiency. As an example, the switching transistor is electrically connected between the floating diffusion FD and the transistor RST.

[0041] 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 efficiency (gain) when converting charge to voltage is switched. The switching transistor can change the conversion efficiency by switching the capacitance connected to the gate of the transistor AMP.

[0042] The above-mentioned transistor TRG (transfer transistor), transistor AMP (amplification transistor), transistor SEL (selection transistor), transistor RST (reset transistor), and switching transistor are each a MOS transistor (MOSFET) having gate, source, and drain terminals.

[0043] 3, the transistor TRG, the transistor AMP, the transistor SEL, and the transistor RST are each configured as an NMOS transistor. Note that the transistor of the pixel P may also be configured as a PMOS transistor.

[0044] The pixel control unit 111 (see Figure 1) of the imaging device 1 supplies control signals to the gates of the transistors TRG, SEL, RST, switching transistors, etc. of each pixel P via the control line L1 described above, turning the transistors on (conducting state) or off (non-conducting state).

[0045] The multiple control lines L1 for each pixel row of the imaging device 1 include, for example, a wiring for transmitting a signal STRG that controls the transistor TRG, a wiring for transmitting a signal SSEL that controls the transistor SEL, and a wiring for transmitting a signal SRST that controls the transistor RST.

[0046] The transistors TRG, SEL, RST, and switching transistors are controlled to be turned on and off by a 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 L2. The pixel control unit 111 can control the reading out of the pixel signal of each pixel P to the signal line L2.

[0047] The imaging device 1 may have a configuration in which a plurality of pixels P share one readout circuit 20. For example, in the imaging device 1, the readout circuit 20 may be provided for a plurality of pixels P. 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.

[0048] [Configuration of Imaging Device] Fig. 4 is a diagram showing an example of the planar configuration of the imaging device according to the first embodiment. Fig. 4 shows an example of the arrangement of pixels P of the pixel unit 100 in the imaging device 1. The pixel P of the imaging device 1 has a light guiding unit 60 and a filter 25. The light guiding unit 60 has a structure 50 configured using a plurality of members (for example, a first member 41 and a second member 42).

[0049] The light-guiding section 60 has, for example, a material layer 45 and a plurality of structures 50 provided in the material layer 45. The structures 50 are configured to include a first member 41 and a second member 42 provided in the first member 41. The structures 50 are provided in the material layer 45, and can also be said to be arranged by replacing part of the material layer 45.

[0050] The structures 50 have, for example, a columnar (pillar-shaped) shape. The structures 50 are pillars (columnar members). The shape of each structure 50 of the light-guiding section 60 can be changed as appropriate. The structures 50 have, for example, a cylindrical shape. The structures 50 may have a polygonal shape in a plan view.

[0051] The first member 41 and the second member 42 may be made of different materials. The second member 42 has a refractive index different from that of the first member 41 and is provided so as to be embedded in the first member 41. The second member 42 may be formed so as to be filled in the first member 41. Note that the number and arrangement of the structures 50 are not limited to the above example and can be changed as appropriate.

[0052] The light guide unit 60 (light guide member) has, for example, a plurality of structures 50 as nanostructures, and is configured to guide incident light toward the photoelectric conversion unit 12. The light guide unit 60 is a light guide element (light guide member) that utilizes metamaterial (metasurface) technology. In the imaging device 1, for example, as in the example shown in FIG. 4 , a light guide unit 60 is provided for each pixel P or for each set of multiple pixels P.

[0053] The filter 25 is configured to selectively transmit light in a specific wavelength range from the incident light. The filter 25 is an RGB color filter, a filter that transmits infrared light, etc. The filter 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) (see also FIG. 5 described later).

[0054] The plurality of pixels P provided in the pixel section 100 of the imaging device 1 includes, for example, a pixel Pr (R pixel) provided with a filter 25 that transmits red (R) light, a pixel Pg (G pixel) provided with a filter 25 that transmits green (G) light, and a pixel Pb (B pixel) provided with a filter 25 that transmits blue (B) light. In the pixel section 100, the plurality of pixels Pr, the plurality of pixels Pg, and the plurality of pixels Pb are repeatedly arranged.

[0055] The pixels Pr, Pg, and Pb are arranged, for example, according to a Bayer array. 2×2 pixels, each consisting of one pixel Pr, two pixels Pg, and one pixel Pb, are repeatedly arranged in the pixel unit 100. The pixel unit 100 has, for example, pixel rows in which the pixels Pg and Pr are alternately arranged, and pixel rows in which the pixels Pb and Pg are alternately arranged.

[0056] The pixels Pr, Pg, and Pb of the pixel unit 100 can generate pixel signals of R, G, and B components, respectively. The imaging device 1 can obtain RGB pixel signals. The arrangement of the pixels P is not limited to the example described above and can be set arbitrarily.

[0057] As an example, the pixels Pr, Pg, and Pb may each be arranged in units of 2×2 pixels. In the pixel unit 100, for example, four adjacent pixels Pr, four adjacent pixels Pg, and four adjacent pixels Pb may be arranged repeatedly. It can also be said that the pixels Pr, Pg, and Pb are each periodically arranged in 2 rows and 2 columns.

[0058] The filter 25 provided in the pixel P of the pixel unit 100 is not limited to a primary color (RGB) color filter, but may be a complementary color filter such as Cy (cyan), Mg (magenta), or Ye (yellow). A filter corresponding to W (white), i.e., a filter that transmits light of the entire wavelength range of incident light, may also be provided. The filter 25 may also be a filter that transmits infrared light.

[0059] Note that the filter 25 may be omitted as needed in the imaging device 1. For example, depending on the characteristics of the light guiding section 60, the filter 25 may not be provided in some or all of the pixels P of the imaging device 1. For example, the filter 25 may not be provided in pixels that receive white (W) light and perform photoelectric conversion.

[0060] Fig. 5 is a diagram showing an example of a cross-sectional configuration of the imaging device according to the first embodiment. As shown in Fig. 5, the imaging device 1 has, for example, an optical layer 80, an insulating layer 90, a filter 25, a semiconductor layer 10, and a wiring layer 95. The imaging device 1 has a configuration in which the optical layer 80, the insulating layer 90, the filter 25, the semiconductor layer 10, and the wiring layer 95 are stacked in the Z-axis direction. From the light incident side, the optical layer 80, the insulating layer 90, a layer in which the filter 25 is provided, the semiconductor layer 10, and the wiring layer 95 are provided.

[0061] The optical layer 80 has the structures 50 and is configured to guide incident light toward the photoelectric conversion body 12. The optical layer 80 has, for example, a plurality of the structures 50 arranged so as to be aligned in the X-axis direction (or the Y-axis direction). In the example shown in FIG. 5 , the optical layer 80 including the structures 50 is stacked on the insulating layer 90.

[0062] The optical layer 80 is an optical element (optical member) that utilizes metamaterial (metasurface) technology. The structure 50 has, for example, a columnar (pillar) shape. The structure 50 can be referred to as a metasurface element. The optical layer 80 can also be referred to as a metasurface layer (or metamaterial layer).

[0063] The optical layer 80 includes a material layer 45 and a structure 50 provided in the material layer 45. The structure 50 has a first member 41 formed in the material layer 45 and a second member 42 formed within the first member 41. The structure 50 is, for example, a pillar (columnar member), and can be called a nanopillar.

[0064] The first member 41 and the second member 42 are made of materials having different refractive indices. Furthermore, the first member 41 may be made of, for example, a material having a different refractive index from the material layer 45. The optical layer 80 may have a light guide section 60 including a structure 50 and a material layer 45 for each pixel P or for each of a plurality of pixels P, as in the example shown in FIG. 5 .

[0065] The semiconductor layer 10 is composed of a semiconductor substrate (for example, a Si (silicon) substrate, an SOI (silicon on insulator) 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.

[0066] 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. The surface 11S1 of the semiconductor layer 10 is, for example, 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 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.

[0067] 5 , a filter 25, an insulating layer 90, etc. are provided on the surface 11S1 side of the semiconductor layer 10. The optical layer 80, the insulating layer 90, and the filter 25 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. The imaging device 1 is a so-called back-illuminated imaging device.

[0068] In the semiconductor layer 10, a plurality of photoelectric conversion units 12 (photoelectric conversion elements) are provided along the surfaces 11S1 and 11S2 of the semiconductor layer 10. For example, the 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 photoelectrically convert light that is incident via the optical layer 80, the insulating layer 90, and the filter 25. The photoelectric conversion units 12 can also be referred to as a photoelectric conversion layer.

[0069] The wiring layer 95 is provided by being stacked on the semiconductor layer 10. The wiring layer 95 includes, for example, a conductor film and an insulating film, and has a plurality of wires and vias (VIAs). The wiring layer 95 is a multi-layer wiring layer, and includes, for example, two or more layers of wires, or three or more layers of wires. The wiring layer 95 has a configuration in which a plurality of wires are stacked via an insulating film serving as an interlayer insulating film (interlayer insulating layer).

[0070] The wiring of the wiring layer 95 is formed using a metal material such as aluminum (Al), tungsten (W), or copper (Cu). 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), or the like.

[0071] In the semiconductor layer 10 and the wiring layer 95, for example, the above-described readout circuit 20 (see FIG. 3 ) is provided for each pixel P or for each set of pixels P. In addition, the above-described pixel control unit 111, signal processing unit 112, control unit 113, processing unit 114, etc. (see FIG. 1 ) may be provided on a substrate separate from the semiconductor layer 10, or on the semiconductor layer 10 and the wiring layer 95.

[0072] The insulating layer 90 is provided between the optical layer 80 having the light-guiding section 60 and the semiconductor layer 10. In the example shown in Fig. 5, the insulating layer 90 is formed so as to be laminated on the layer on which the filter 25 is provided. The insulating layer 90 is made of an insulating film such as an oxide film, a nitride film, or an oxynitride film. The insulating layer 90 may be made of an insulating material such as silicon oxide (SiO2), silicon nitride (SiN2), or aluminum oxide (AlO2), or may be made of other materials.

[0073] The insulating layer 90 may be made of a material with a low refractive index, such as silicon oxide, or may be made of another material that transmits light in the wavelength range to be measured. The insulating layer 90 can also be called a transparent layer that transmits light, or a spacer layer. Note that the optical layer 80 may be configured to include the insulating layer 90.

[0074] As shown in FIG. 5 , the imaging device 1 has an isolation region 30, which is an isolation region (isolation section) provided around a pixel P (or a photoelectric conversion section 12). The isolation region 30 is provided between adjacent pixels P in the semiconductor layer 10, and separates the pixels P (or the photoelectric conversion sections 12). At least a portion of the isolation region 30 is provided at the boundary between adjacent pixels P (or the photoelectric conversion sections 12). The isolation region 30 is formed using, for example, a trench (groove section).

[0075] The isolation region 30 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. The isolation region 30 may be provided so as to penetrate the semiconductor layer 10. That is, the isolation region 30 may be formed so as to reach the surface 11S2 of the semiconductor layer 10. The isolation region 30 may also be referred to as a pixel isolation portion or a pixel isolation wall.

[0076] An insulating film, such as a silicon oxide film, a silicon nitride film, or an aluminum oxide film, is provided in the trench of the isolation region 30. Polysilicon, a metal material, another insulating material, or the like may be buried in the trench of the isolation region 30. The isolation region 30 may be configured by a semiconductor region (a p-type semiconductor region or an n-type semiconductor region) formed by ion implantation.

[0077] The separation region 30 may be formed using other insulating materials having a low refractive index. A gap (cavity) may be provided within the separation region 30. The provision of the separation region 30 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, the separation region 30 prevents unnecessary light from leaking to the surrounding pixels P, thereby preventing, for example, color mixing.

[0078] The imaging device 1 may have at least one of a fixed charge film and an antireflection film on the surface 11S1 side of the semiconductor layer 10. The fixed charge film and the antireflection film are, for example, made of a metal compound (metal oxide, metal nitride, etc.) and can also be called a metal compound layer.

[0079] The fixed charge film and anti-reflection film are provided, for example, between the semiconductor layer 10 and the filter 25. The fixed charge film is a film having a fixed charge and can be formed using a high dielectric material. For example, the fixed charge film is made of a metal oxide such as hafnium oxide or aluminum oxide. The fixed charge film is, for example, a film having a negative fixed charge.

[0080] 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. A film having a positive fixed charge may be provided as the fixed charge film.

[0081] 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 (SiN), silicon oxide (SiO), or aluminum oxide (AlO), or may be made of other materials.

[0082] 5 , the optical layer 80 is provided above the photoelectric conversion unit 12. Light from a subject serving as a measurement target is incident on the light guiding unit 60. For example, light that has passed through an optical system such as an imaging lens is incident on the structure 50 of the light guiding unit 60. For example, the structure 50 is a structure having a size equal to or smaller than a predetermined wavelength of the incident light.

[0083] The optical layer 80 (or the light guide section 60) has structures 50 which are nanostructures, and is configured to guide light incident from above in FIG. 5 to the photoelectric conversion section 12 side. The structures 50 have a size equal to or smaller than the wavelength range of light to be measured, for example, a size equal to or smaller than the wavelength range of visible light. The structures 50 may also have a size equal to or smaller than the wavelength range of infrared light.

[0084] The multiple structures 50 of the optical layer 80 are arranged side by side in the X-axis direction (or Y-axis direction) with a portion of the material layer 45 sandwiched between them. The structures 50 are made of multiple materials and have, for example, a cylindrical shape. The shape of the structures 50 can be changed as appropriate and may be circular or rectangular in plan view. The shape of the structures 50 may be elliptical, polygonal, cross-shaped, or any other shape.

[0085] 4 and 5 , the second member 42 is provided within the first member 41. For example, the second member 42 is provided so as to be embedded within the first member 41 provided in the material layer 45. The first member 41 and the second member 42 can be formed so as to fill holes (openings) in the material layer 45. The material layer 45 is a member located around the structure 50, and can also be called a protective member (protective layer) or a supporting member.

[0086] The second member 42 is provided in contact with the first member 41 in the X-axis direction (or Y-axis direction). Furthermore, the second member 42 may be provided in contact with a portion of the first member 41 in the Z-axis direction and positioned on top of a portion of the first member 41, as in the example shown in FIG. 5 . In the example shown in FIG. 5 , the lower end (bottom) of the second member 42 is in contact with the first member 41. The second member 42 is stacked on a portion of the first member 41 and disposed in contact with the first member 41.

[0087] In this disclosure, "in contact" includes direct contact and contact via a natural oxide film, etc. "The second member 42 and the first member 41 are in contact" includes a case where a natural oxide film is present, and also includes a case where the second member 42 is in contact with the first member 41 via a thin natural oxide film.

[0088] In the imaging device 1, reflection can be suppressed by providing a part of the first member 41 between the stopper film 46 and the second member 42. This allows light to be efficiently guided to the photoelectric conversion unit 12 side, making it possible to improve quantum efficiency (QE).

[0089] The light guide unit 60 uses the structure 50, which is a nanostructure, to propagate light toward the photoelectric conversion unit 12. The structure 50 is also called, for example, a meta-atom, a nano-atom, a nano-post, a metasurface structure, or a microstructure. The light guide unit 60 is an optical element (optical member) that guides (propagates) light.

[0090] The light-guiding unit 60 is configured as, for example, a light-guiding element that can impart a phase delay to incident light and guide the light. As an example, a plurality of structures 50 are formed in the optical layer 80 so as to impart a desired phase profile to the incident light. For example, the size, number of structures 50, arrangement interval (pitch), etc. are determined so that light in a wavelength band to be detected is focused onto the photoelectric conversion unit 12.

[0091] In the optical layer 80, for example, the plurality of structures 50 are arranged at intervals equal to or less than a predetermined wavelength of incident light. As an example, the plurality of structures 50 are provided in the X-axis direction and the Y-axis direction at intervals equal to or less than the wavelength range of visible light. Note that in the pixel P, the plurality of structures 50 may be arranged at intervals equal to or less than the wavelength range of infrared light.

[0092] The structure 50 is configured to have a refractive index different from that of an adjacent medium. The second member 42 has a refractive index different from that of the medium surrounding the second member 42, i.e., the first member 41. The second member 42 has a refractive index higher than that of the first member 41, for example.

[0093] The second member 42 is made of, for example, a material having a refractive index higher than that of the first member 41. The first member 41 may also be made of a material having a refractive index equal to or higher than that of the material layer 45. The second member 42 is made of a high refractive index material and can also be called a high refractive index portion. The first member 41 is made of a low refractive index material and can also be called a low refractive index portion.

[0094] The first member 41 and the second member 42 may be made of different materials. For example, the first member 41 and the second member 42 may be made of an inorganic material. The material making up the second member 42 and the first member 41 may be selected depending on the refractive index difference with the surrounding medium, the wavelength range of the incident light to be measured, etc.

[0095] The second member 42 is made of, for example, an oxide film containing titanium (Ti). As an example, the second member 42 is made of titanium oxide (TiO). As another example, the second member 42 may be made of silicon, polysilicon (Poly-Si), amorphous silicon (a-Si), germanium (Ge), or the like.

[0096] The second member 42 may be made of titanium (Ti), hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), indium (In), niobium (Nb), or the like, or an oxide, nitride, oxynitride, or a composite thereof.

[0097] The second member 42 may be made of other metal compounds (metal oxides, metal nitrides, etc.). The second member 42 may be made of GaP, GaN, GaAs, etc. The second member 42 may also be made of silicon carbide (SiC) or other silicon compounds.

[0098] The first member 41 is made of, for example, an inorganic material such as an oxide, a nitride, or an oxynitride. The first member 41 may be made of, for example, silicon oxide (SiO), silicon nitride (SiN), or silicon oxynitride (SiON). The first member 41 may be made of silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, or other silicon compounds.

[0099] The first member 41 and the second member 42 may be made of an organic material. The first member 41 and the second member 42 may be made of, for example, a siloxane-based resin, a styrene-based resin, an acrylic-based resin, or the like. The first member 41 (or the second member 42) may be made of a material in which any of these resins contains fluorine. The first member 41 (or the second member 42) may be formed of 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 material layer 45 is formed using an inorganic material such as an oxide, a nitride, or an oxynitride. For example, the material layer 45 is formed using TEOS. The material layer 45 may be formed using silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or the like, or may be formed using other silicon compounds.

[0101] The material layer 45 may be made of an organic material. The material layer 45 may be made of a siloxane-based resin, a styrene-based resin, an acrylic-based resin, or the like. The material layer 45 may be made of a material in which any of these resins contains fluorine. The material layer 45 may be formed using a material in which any of these resins is filled with beads having a higher refractive index than the resin.

[0102] The light-guiding section 60 of the optical layer 80 can control the wavefront of the light by causing a phase delay in the incident light due to, for example, a difference in refractive index between the structures 50 and the medium surrounding them. The light-guiding section 60 can adjust the propagation direction of the light by, for example, imparting a phase delay to the incident light using the structures 50 constituted by the first member 41 and the second member 42.

[0103] The materials (optical constants of each material) of the first member 41, the second member 42, and the material layer 45, the sizes (width (diameter), height, etc.), the pitch (arrangement interval), etc. of the first member 41 and the second member 42 are determined so that light in a desired wavelength range, among the incident light from the measurement target, travels in a desired direction. For example, the materials (refractive index), dimensions, pitch, etc. of the first member 41 and the second member 42 can be set.

[0104] As an example, in the imaging device 1, the material, size, arrangement number, etc. of the structures 50 of each pixel P are determined so that light in a specific wavelength band to be detected travels to the photoelectric conversion unit 12 of the desired pixel P. For example, the structures 50 of the light guide units 60 of the pixels Pr, Pg, and Pb may be formed so that their sizes (e.g., width, height), arrangement positions, etc. are different from one another.

[0105] The optical layer 80 (or the light guide 60) may be configured as, for example, a spectroscopic unit (spectroscopic element) capable of separating incident light. The optical layer 80 (or the light guide 60) may be configured as a splitter (color splitter) and may also be referred to as a color splitter layer or a wavelength separation layer. The optical layer 80 (or the light guide 60) may also be referred to as an optical element configured to redirect light.

[0106] The imaging device 1 may be provided with a stopper film 46, as in the example shown in Fig. 5 . In the example shown in Fig. 5 , the optical layer 80 has a stopper film 46 provided between the structure 50 and the insulating layer 90. The stopper film 46 serves as an etching stopper film (stopper layer) during the manufacture of the imaging device 1. By providing the stopper film 46, it is possible to improve the processing controllability of the structure 50. The stopper film 46 can also be called an etching prevention film (or etching suppression film).

[0107] The stopper film 46 is configured by, for example, a single layer film made of one of silicon nitride (SiN), silicon oxynitride (SiON), aluminum oxide (AlO), hafnium oxide (HfO), etc., or a laminated film made of two or more of these materials. Note that the stopper film 46 may also be formed using other materials.

[0108] As described above, light from a subject to be measured is incident on each pixel P of the imaging device 1 via the optical layer 80. Each pixel P can receive the light incident via the structure 50 of the light-guiding section 60 and generate a pixel signal. The imaging device 1 can generate image data representing an image of the subject using the pixel signal obtained by photoelectric conversion in each pixel P.

[0109] Furthermore, the imaging device 1 can generate image data (distance image data) relating to the distance to an object, for example, using the pixel signal of each pixel. In this embodiment, the light guide unit 60 having the structure 50 can appropriately guide light to the photoelectric conversion unit 12. The metasurface element can efficiently guide light in any wavelength range to the photoelectric conversion unit 12.

[0110] In the imaging device 1, as described above, the structure 50 of the light guiding unit 60 is configured using a first member 41 and a second member 42 provided within the first member 41. The second member 42 can be provided in contact with the first member 41 in the X-axis direction (or Y-axis direction) and the Z-axis direction. By forming the second member 42 so as to be embedded in the first member 41, it is possible to realize the second member 42 having a high aspect ratio.

[0111] In this embodiment, it is possible to form a minute (fine) second member 42 as a high refractive index portion. This allows for improved design freedom and improved light controllability. It is possible to form a structure 50 including a second member 42 having a desired diameter (width), and the optical characteristics of the optical layer 80 (light guide section 60) can be improved. It is possible to realize a photodetector with good optical characteristics.

[0112] 6A to 6E are diagrams illustrating an example of a method for manufacturing the light guide portion of the imaging device according to the first embodiment. First, as shown in FIG. 6A, a material layer 45 made of a low-refractive-index material (e.g., TEOS) is formed on an insulating layer 90 on which a stopper film 46 (e.g., a SiN film) is formed. Then, as shown in FIG. 6B, the material layer 45 is selectively removed by lithography and etching to form a plurality of holes 48 in the material layer 45.

[0113] Next, as shown in Fig. 6C, an SiO film 71 serving as a low refractive index portion is formed by ALD (Atomic Vapor Deposition) along the side surface (side portion) of the hole 48. Furthermore, as shown in Fig. 6D, a TiO film 72 serving as a high refractive index portion is formed by ALD so as to fill the inside of the hole 48 (opening).

[0114] Next, as shown in Fig. 6E, a portion of the SiO film 71 and a portion of the TiO film 72 are removed by CMP (Chemical Mechanical Polishing). The excess portion of the SiO film 71 is removed to form the first member 41. The excess portion of the TiO film 72 is removed to form the second member 42. The light guide unit 60 shown in Fig. 5 and other figures can be manufactured by the manufacturing method described above. Note that the manufacturing method described above is merely an example, and other manufacturing methods may also be used.

[0115] [Actions and Effects] The photodetector according to this embodiment includes a first layer (optical layer 80) including a first material layer (material layer 45) on which first structures (structures 50) having a columnar shape are provided, and a photoelectric conversion element (photoelectric conversion unit 12) that photoelectrically converts light incident through the first layer. The first structures include a first member (first member 41) provided in the first material layer, and a second member (second member 42) provided within the first member and having a refractive index different from that of the first member.

[0116] In the photodetector (imaging device 1) according to this embodiment, the structure 50 includes a first member 41 and a second member 42 that is provided within the first member 41 and has a refractive index different from that of the first member 41. This makes it possible to form a minute second member 42, thereby improving the optical characteristics. This makes it possible to realize a photodetector that can suppress deterioration in quality.

[0117] 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.

[0118] (Variation 1) Fig. 7 is a diagram for explaining a configuration example of an imaging device according to Variation 1 of the present disclosure. The second member 42 of the structure 50 may be provided so as to penetrate the first member 41. The second member 42 may be formed so as to reach, for example, the stopper film 46. In the example shown in Fig. 7, the second member 42 is provided so that the bottom (lower end) of the second member 42 contacts the stopper film 46. In this variation as well, it is possible to form a structure 50 having a second member 42 with a desired width (diameter).

[0119] 8A to 8F are diagrams illustrating an example of a method for manufacturing a light guide section of an imaging device according to Modification 1. First, as shown in Fig. 8A, a material layer 45 is formed on an insulating layer 90 on which a stopper film 46 has been formed. Then, as shown in Fig. 8B, the material layer 45 is partially removed by lithography and etching to form a plurality of holes 48 (openings) in the material layer 45.

[0120] 8C, a SiO film 71 is formed by, for example, ALD so as to extend along the side surface (sidewall) of the hole 48. Then, the SiO film 71 is partially removed by an etch-back process, thereby forming the first member 41 as shown in FIG.

[0121] Next, as shown in Fig. 8E, a TiO film 72 is formed by ALD so as to fill the hole 48. Then, the TiO film 72 is partially removed by CMP processing, thereby forming the second member 42 as shown in Fig. 8F. The light guide section 60 shown in Fig. 7 can be manufactured by the manufacturing method described above. Note that the manufacturing method described above is merely an example, and other manufacturing methods may also be adopted.

[0122] 9 is a diagram illustrating a configuration example of an imaging device according to Modification 2. Some of the structures 50 of the optical layer 80 may be composed of a plurality of members, for example, a first member 41 and a second member 42. For example, as in the example shown in FIG. 9 , the light guiding section 60 may have a structure 50 composed of the second member 42 and a structure 50 composed of the first member 41 and the second member 42.

[0123] For example, in the imaging device 1, pupil correction can be appropriately performed by configuring the structures 50 of the light guide unit 60 of each pixel P to differ depending on the image height. For example, the number and arrangement positions of the structures 50 made up of the first member 41 and the second member 42 are adjusted depending on the image height, which can prevent a decrease in the amount of light incident on the photoelectric conversion unit 12 of each pixel P. It is possible to improve sensitivity to incident light.

[0124] 10 is a diagram illustrating another example configuration of an imaging device according to Modification 2. Structures 50 of different sizes (width, height, cross-sectional area, etc.) may be provided in the optical layer 80. For example, in order to obtain desired optical characteristics (e.g., light refraction characteristics), structures 50 of different widths (diameters) may be provided, as in the example shown in FIG.

[0125] 11A and 11B are diagrams for explaining a configuration example of a light guiding section of an imaging device according to Modification 3. In the above-described embodiment and modifications, configuration examples of the structure 50 have been described, but these are merely examples, and the configuration of the structure 50 is not limited to the above-described example. For example, the shape of the structure 50 can be changed as appropriate.

[0126] As shown in the example of Fig. 11A, the shape of the structure 50 may be a rectangle or a hexagon in a plan view. Furthermore, as shown in the example of Fig. 11B, the shape of the structure 50 may be a cross in a plan view. The shape of the structure 50 may also be a polygon, an ellipse, or another shape.

[0127] (Modification 4) Fig. 12 is a diagram for explaining a configuration example of an imaging device according to Modification 4. As in the example shown in Fig. 12, the width (length) of the structure 50 on the stopper film 46 side (or the insulating layer 90 side) may be different from the width of the structure 50 on the side opposite to the stopper film 46 side. For example, the structure 50 may be formed so that the width of the upper end (tip) of the structure 50 is larger (thicker) than the width of the lower end (bottom) of the structure 50. The structure 50 may have a tapered shape.

[0128] The width of the structure 50 in the X-axis direction (or Y-axis direction) increases, for example, as it moves away from the stopper film 46. It can also be said that the width (thickness) of the structure 50 in the X-axis direction (or Y-axis direction) decreases as it approaches the stopper film 46 (or the insulating layer 90). In the example shown in FIG. 12 , the width of the structure 50 gradually increases (thickens) from the bottom to the top of the structure 50. Note that the structure 50 may be formed so that the width of the upper end of the structure 50 is smaller (thinner) than the width of the lower end of the structure 50.

[0129] 13 and 14 are diagrams illustrating an example configuration of an imaging device according to Modification 5. FIG. 13 shows an example of a planar configuration of a portion of the imaging device 1, and FIG. 14 shows an example of a cross-sectional configuration of a portion of the imaging device 1. The structure 50 of the light guiding section 60 may have a configuration that combines three or more materials. For example, as in the example shown in FIGS. 13 and 14 , the structure 50 may have a third member 43 provided within the second member 42.

[0130] The third member 43 of the structure 50 may be made of, for example, a material different from that of the second member 42. The third member 43 is provided so as to be embedded in the second member 42, and has a refractive index different from that of the second member 42. The third member 43 may be formed so as to fill the second member 42. Note that the third member 43 may be formed so as to reach the stopper film 46.

[0131] The third member 43 has a refractive index different from the refractive index of the surrounding medium. The third member 43 has a refractive index different from the refractive index of the second member 42 and the refractive index of the first member 41, for example. The third member 43 may have a refractive index higher than the refractive index of the second member 42. The third member 43 may also have a refractive index higher than the refractive index of the material layer 45. In this modified example, the same effects as those of the above embodiment can be obtained.

[0132] The shape of the structure 50 can be changed as appropriate. As shown in the example of Fig. 13, the structure 50 may have a circular shape in a plan view. The shape of the structure 50 may be a polygon, an ellipse, or another shape. The structure 50 may have a hexagonal shape or a cross shape in a plan view.

[0133] (Variation 6) In the above-described embodiment and variations, configuration examples of the light detection device have been described, but the configuration of the light detection device (imaging device) is not limited to the above-described examples. For example, the imaging device 1 may have a layered structure in which two or three or more optical layers are stacked. The light guide unit 60 may be configured to include, for example, two or more stages of nanostructures.

[0134] 15 is a diagram illustrating a configuration example of an imaging device according to Modification 6. The imaging device 1 may have a multi-layer (multi-stage) structure 50. The imaging device 1 has a plurality of structures (structures 50a and 50b in the example shown in FIG. 15) that are stacked on top of each other.

[0135] The imaging device 1 has a first optical layer 80a (first layer) including, for example, a material layer 45a, a structure 50a having a first member 41a and a second member 42a, and a stopper film 46a. The second member 42a is provided in contact with the first member 41a in the X-axis direction (or the Y-axis direction). Furthermore, the second member 42a may be provided in contact with a portion of the first member 41a in the Z-axis direction and positioned on top of a portion of the first member 41a, as in the example shown in FIG. 15 .

[0136] The imaging device 1 also has a second optical layer 80b (second layer) including a material layer 45b, a structure 50b having a first member 41b and a second member 42b, and a stopper film 46b. The second member 42b is provided in contact with the first member 41b in the X-axis direction (or the Y-axis direction). The second member 42b may be provided in contact with a portion of the first member 41b in the Z-axis direction and positioned on top of a portion of the first member 41b, as in the example shown in FIG. 15 .

[0137] The second optical layer 80b can be provided by being stacked on the first optical layer 80a. The light guide section 60 has, for example, a first-stage structure 50a and a second-stage structure 50b. In the case of this modification, the same effects as those of the above-described embodiment can be obtained. It is possible to realize a photodetector with good performance.

[0138] 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 light guide section 60 (or 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.

[0139] 16 is a diagram illustrating an example configuration of an optical element according to a 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 plurality of structures 50 configured using a plurality of members (e.g., a first member 41 and a second member 42). The optical element 200 is an optical element (optical member) configured using the structures 50, which are nanostructures, and can be configured as a metalens (metamaterial lens).

[0140] 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 50. 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 (base material) may also be made of another material that transmits the light to be measured.

[0141] As shown in Fig. 16 , 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 side of the substrate 120 where light is incident. In the example shown in Fig. 16 , the optical layer 80 including a plurality of structures 50 is formed on the surface 12S1 of the substrate 120.

[0142] The optical layer 80 including the structures 50 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 50 are not limited to the example shown in the figure, and can be changed as appropriate.

[0143] The optical element 200 may be configured as, for example, a lens that condenses light, a lens that diffuses light, or the like. The optical element 200 may also be configured as a splitter that disperses incident light, a filter that transmits light in a specific wavelength range, a deflector that changes the traveling direction of light, or the like. The optical element 200 may be configured as, for example, a part of the optical system of various devices.

[0144] [Actions and Effects] The optical element according to the present embodiment includes a first material layer (material layer 45) and a columnar first structure (structure 50) provided in the first material layer. The first structure includes a first member (first member 41) provided in the first material layer, and a second member (second member 42) provided within the first member and having a refractive index different from that of the first member.

[0145] In the optical element (optical element 200) according to this embodiment, the structure 50 includes a first member 41 and a second member 42 that is provided within the first member 41 and has a refractive index different from that of the first member 41. This makes it possible to form a minute second member 42, thereby improving the characteristics with respect to incident light. It is possible to realize an optical element with good optical characteristics.

[0146] 3. Application Examples The imaging device 1 and the like can be applied to any type of electronic device with an imaging function, for example, a camera system such as a digital still camera or a video camera, a mobile phone with an imaging function, etc. Fig. 17 shows a schematic configuration of an electronic device 1000.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] FIG. 18 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.

[0154] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 18, 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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. 18, 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.

[0164] FIG. 19 is a diagram showing an example of the installation position of the imaging unit 12031.

[0165] In FIG. 19, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0166] 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.

[0167] 19 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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 or the like 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 high-resolution captured images. It becomes possible to perform high-precision control using captured images in the mobile object control system.

[0173] (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.

[0174] FIG. 20 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.

[0175] 20 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.

[0176] 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.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] FIG. 21 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] 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 .

[0197] 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.

[0198] 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.

[0199] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0200] 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.

[0201] 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.

[0202] 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.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] 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.).

[0208] According to an embodiment of the present disclosure, a photodetector includes a first layer including a first material layer having a columnar first structure provided therein, and a photoelectric conversion element that photoelectrically converts light incident through the first layer. The first structure includes a first member provided in the first material layer and a second member provided within the first member and having a refractive index different from that of the first member. This makes it possible to realize a photodetector that can suppress deterioration in quality.

[0209] An optical element according to an embodiment of the present disclosure includes a first material layer and a columnar first structure provided in the first material layer. The first structure includes a first member provided in the first material layer and a second member provided within the first member and having a refractive index different from that of the first member. This makes it possible to realize an optical element with excellent optical properties.

[0210] 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) A photodetector including: a first layer including a first material layer on which first structures having a columnar shape are provided; and a photoelectric conversion element that photoelectrically converts light incident through the first layer, wherein the first structures include: a first member provided in the first material layer; and a second member provided within the first member and having a refractive index different from that of the first member. (2) The photodetector described in (1), wherein the first layer includes a plurality of the first structures arranged to be aligned in a first direction; and the second member is in contact with the first member in the first direction. (3) The photodetector described in (2), wherein the second member is provided on a portion of the first member and is in contact with the first member in a second direction perpendicular to the first direction. (4) The photodetector according to any one of (1) to (3), wherein the first layer includes a first stopper film provided under the first material layer, and a portion of the first member is provided between the second member and the first stopper film. (5) The photodetector according to any one of (1) to (4), wherein the first member is provided so as to be embedded in the first material layer and is made of an inorganic material, and the second member is provided so as to be embedded in the first member and is made of an inorganic material. (6) The photodetector according to any one of (1) to (5), wherein the refractive index of the second member is higher than the refractive index of the first member. (7) The photodetector according to any one of (1) to (6), wherein the refractive index of the first member is equal to or higher than the refractive index of the first material layer. (8) The photodetector according to any one of (1) to (7), wherein the first structure has a width equal to or shorter than the wavelength of visible light or the wavelength of infrared light. (9) The photodetector according to any one of (1) to (8), wherein the first structure has a circular shape or a polygonal shape. (10) The photodetector according to any one of (1) to (9), wherein the first layer has a plurality of the first structures having different widths.(11) The photodetector according to any one of (1) to (10), further comprising a second layer including a second material layer on which second structures having a columnar shape are provided, the second layer being stacked on the first layer, wherein the second structures include: a third member provided in the second material layer; and a fourth member provided within the third member and having a refractive index different from that of the third member. (12) The photodetector according to (11), wherein the second layer includes a plurality of the second structures arranged to be aligned in a first direction, and the fourth member is in contact with the third member in the first direction. (13) The photodetector according to (12), wherein the fourth member is provided on a portion of the third member and is in contact with the third member in a second direction perpendicular to the first direction. (14) The photodetector according to any one of (11) to (13), wherein the second layer includes a second stopper film provided below the second material layer, and a portion of the third member is provided between the fourth member and the second stopper film. (15) The photodetector according to any one of (1) to (14), wherein the first structure includes a fifth member provided in the second member and having a refractive index different from that of the second member. (16) An optical element comprising: a first material layer; and a first structure provided in the first material layer and having a columnar shape, wherein the first structure includes: a first member provided in the first material layer; and a second member provided in the first member and having a refractive index different from that of the first member. (17) The optical element according to (16), wherein the first structure includes a plurality of the first structures arranged to be aligned in a first direction, and the second member is in contact with the first member in the first direction. (18) The optical element according to (17), wherein the second member is provided on a part of the first member and is in contact with the first member in a second direction perpendicular to the first direction. (19) The optical element according to any one of (16) to (18), wherein a refractive index of the second member is higher than a refractive index of the first member.(20) An electronic device comprising: an optical system; and a photodetector that receives light transmitted through the optical system, wherein the photodetector has: a first layer including a first material layer in which a first structure having a columnar shape is provided; and a photoelectric conversion element that photoelectrically converts light incident through the first layer, and the first structure includes: a first member provided in the first material layer; and a second member provided within the first member and having a refractive index different from that of the first member.

[0211] This application claims priority based on Japanese Patent Application No. 2024-012469, filed on January 31, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0212] 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. A photodetector comprising: a first layer including a first material layer on which a columnar first structure is provided; and a photoelectric conversion element that photoelectrically converts light incident through said first layer, wherein said first structure includes a first member provided in said first material layer; and a second member provided within said first member and having a refractive index different from that of said first member.

2. The photodetector according to claim 1, wherein the first layer includes a plurality of the first structures arranged in a first direction, and the second member is in contact with the first member in the first direction.

3. The optical detection device according to claim 2, wherein the second member is provided on a portion of the first member and is in contact with the first member in a second direction perpendicular to the first direction.

4. The photodetector according to claim 1, wherein the first layer includes a first stopper film provided below the first material layer, and a portion of the first member is provided between the second member and the first stopper film.

5. The photodetector according to claim 1, wherein the first member is embedded in the first material layer and is made of an inorganic material, and the second member is embedded in the first member and is made of an inorganic material.

6. The photodetector according to claim 1, wherein the refractive index of the second member is higher than the refractive index of the first member.

7. The photodetector according to claim 1, wherein the refractive index of the first member is equal to or greater than the refractive index of the first material layer.

8. The photodetector according to claim 1, wherein the first structure has a width equal to or less than the wavelength of visible light or equal to or less than the wavelength of infrared light.

9. The photodetector according to claim 1, wherein the first structure has a circular or polygonal shape.

10. The photodetector device according to claim 1, wherein the first layer has a plurality of the first structures having different widths.

11. The photodetector according to claim 1, further comprising a second layer provided with a second structure having a columnar shape and stacked on the first layer, wherein the second structure includes: a third member provided in the second material layer; and a fourth member provided within the third member and having a refractive index different from that of the third member.

12. The photodetector device according to claim 11, wherein the second layer includes a plurality of the second structures arranged in a first direction, and the fourth member is in contact with the third member in the first direction.

13. The optical detection device according to claim 12, wherein the fourth member is provided on a part of the third member and is in contact with the third member in a second direction perpendicular to the first direction.

14. The photodetector device according to claim 11, wherein the second layer includes a second stopper film provided below the second material layer, and a portion of the third member is provided between the fourth member and the second stopper film.

15. The photodetector according to claim 1, wherein the first structure includes a fifth member provided within the second member and having a refractive index different from that of the second member.

16. An optical element comprising: a first material layer; and a first structure provided in the first material layer and having a columnar shape, wherein the first structure includes a first member provided in the first material layer; and a second member provided within the first member and having a refractive index different from that of the first member.

17. The optical element according to claim 16, comprising a plurality of the first structures arranged to be aligned in a first direction, and the second member contacting the first member in the first direction.

18. The optical element according to claim 17, wherein the second member is provided on a portion of the first member and is in contact with the first member in a second direction perpendicular to the first direction.

19. The optical element according to claim 16, wherein the refractive index of the second member is higher than the refractive index of the first member.

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 first layer including a first material layer on which a first structure having a columnar shape is provided; and a photoelectric conversion element that photoelectrically converts light that is incident through the first layer, and the first structure includes a first member provided in the first material layer; and a second member provided within the first member and having a refractive index different from that of the first member.

Images