Photodetector, optical element, and electronic apparatus

Abstract

To provide a photodetector that makes it possible to improve characteristics for incident light.SOLUTION: A photodetector according to one embodiment disclosed herein comprises: a first layer including a plurality of first structures and a first medium having a refractive index different from a refractive index of the first structure; a second layer including a plurality of second structures and a second medium having a refractive index different from a refractive index of the second structure, the second layer stacked on the first layer; and a photoelectric conversion element that photoelectrically converts light incident via the second layer and the first layer. The second structure is formed of the same material as that of the first structure. The plurality of second structures include the second structure in contact with the first structure.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] An image sensor has been proposed having a first lens layer including a plurality of nanoposts, a second lens layer including a plurality of nanoposts, and an etching prevention layer disposed between the first lens layer and the second lens layer (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-74062 Summary of the Invention [Problem to be solved by the invention]

[0004] In a light detecting device, it is desirable to improve characteristics with respect to incident light.

[0005] It is desirable to provide a photodetector device that can improve characteristics with respect to incident light. [Means for solving the problem]

[0006] A photodetector according to an embodiment of the present disclosure includes a first layer having a plurality of first structures arranged in a first direction, a first medium arranged around the first structures and having a refractive index different from that of the first structures, a plurality of second structures arranged in a first direction, a second layer having a second medium arranged around the second structures and having a refractive index different from that of the second structures and stacked on the first layer, and a photoelectric conversion element that photoelectrically converts light incident through the second layer and the first layer. The second structures are made of the same material as the first structures. The plurality of second structures includes a second structure in contact with the first structures. An optical element according to an embodiment of the present disclosure includes a first layer having a first structure arranged in a first direction, a first medium arranged around the first structure and having a refractive index different from that of the first structure, and a second layer having a second structure arranged in a first direction, a second medium arranged around the second structure and having a refractive index different from that of the second structure, and laminated on the first layer. The second structure is made of the same material as the first structure. The second structure includes a second structure in contact with the first structure. 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 having a first structure arranged in a first direction, a first medium arranged around the first structure and having a refractive index different from that of the first structure, a second layer having a second medium arranged around the second structure and having a refractive index different from that of the second structure, and stacked on the first layer, and a photoelectric conversion element that photoelectrically converts light incident through the second layer and the first layer. The second structure is made of the same material as the first structure. The second structure includes a second structure in contact with the first structure. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram showing an example of a schematic configuration of an imaging device which is an example of a light detection device according to a first embodiment of the present disclosure. [Diagram 2] 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. [Diagram 3] 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. [Figure 4] 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. [Diagram 5] 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. [Figure 6A]FIG. 6A is a diagram illustrating an example of a planar configuration of a light guiding unit of the imaging device according to the first embodiment of the present disclosure. [Figure 6B] FIG. 6B is a diagram illustrating an example of a planar configuration of the light guiding unit of the imaging device according to the first embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram for explaining another configuration example of the imaging device according to the first embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram for explaining another configuration example of the light guiding section of the imaging device according to the first embodiment of the present disclosure. [Figure 9A] FIG. 9A is a diagram for explaining another configuration example of the light guiding section of the imaging device according to the first embodiment of the present disclosure. [Figure 9B] FIG. 9B is a diagram for explaining another configuration example of the light guiding section of the imaging device according to the first embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram for explaining another configuration example of the light guiding section of the imaging device according to the first embodiment of the present disclosure. As shown in FIG. [Figure 11A] FIG. 11A is a diagram for explaining an example of a method for manufacturing a light guiding section of an imaging device according to the first embodiment of the present disclosure. [Figure 11B] FIG. 11B is a diagram for explaining an example of a method for manufacturing the light guiding section of the imaging device according to the first embodiment of the present disclosure. [Figure 11C] FIG. 11C is a diagram for explaining an example of a method for manufacturing a light guiding section of an imaging device according to the first embodiment of the present disclosure. [Figure 11D] FIG. 11D 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. [Figure 12] FIG. 12 is a diagram for explaining a configuration example of an imaging device according to a modified example of the present disclosure. [Figure 13] FIG. 13 is a diagram for explaining a configuration example of an optical element according to the second embodiment of the present disclosure. [Figure 14] FIG. 14 is a diagram for explaining a configuration example of an optical element according to the second embodiment of the present disclosure. [Figure 15]FIG. 15 is a block diagram illustrating an example of the configuration of an electronic device having an imaging device. [Figure 16] FIG. 16 is a block diagram showing an example of a schematic configuration of a vehicle control system. [Figure 17] FIG. 17 is an explanatory diagram showing an example of the installation positions of the vehicle outside information detection unit and the imaging unit. [Figure 18] FIG. 18 is a diagram showing an example of a schematic configuration of an endoscopic surgery system. [Figure 19] FIG. 19 is a block diagram showing an example of a functional configuration of the camera head and the CCU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 Examples 4. Application Examples

[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 light detection 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 light detection device is a device capable of detecting incident light. The imaging device 1 which is a light detection device has a plurality of pixels P each having a photoelectric conversion unit (photoelectric conversion element), and is configured to perform photoelectric conversion on the incident light to generate a signal.

[0010] The imaging device 1 can generate a signal by receiving light transmitted 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) and configured to be capable of photoelectrically converting 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 two-dimensionally arranged 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 called a light receiving region. The photoelectric conversion section of each pixel P can also be called 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 light detection device, 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 (photodetection device) 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 (layered structure) formed by stacking a plurality of semiconductor layers. The imaging device 1 may be used in various electronic devices such as digital still cameras, video cameras, and mobile phones.

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

[0015] [Schematic configuration of the imaging device] 1, the imaging device 1 includes a pixel unit 100, a pixel control unit 111, a signal processing unit 112, a control unit 113, and a processing unit 114. The imaging device 1 is also provided with, for example, a plurality of control lines Lread and a plurality of signal lines VSL. The control line Lread is a signal line capable of transmitting a signal for controlling the pixel P, and is connected to the pixel control unit 111 and the pixel P of the pixel unit 100.

[0016] 1, in the pixel section 100, a plurality of control lines Lread are wired for each pixel row composed of a plurality of pixels P arranged in the horizontal direction (row direction). The control lines Lread are configured to transmit control signals for reading out signals from the pixels P. The control lines Lread can also be considered as drive lines (pixel drive lines) that transmit signals for driving the pixels P.

[0017] The signal line VSL is a signal line capable of transmitting a signal from a 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 VSL are wired for each pixel column composed of a plurality of pixels P arranged in the vertical direction (column direction). The signal line VSL is configured to be able to transmit a signal output from the pixel P. In the imaging device 1, multiple signal lines VSL may be provided for one pixel column. The imaging device 1 may have multiple signal lines VSL for each pixel column.

[0018] 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 the signal to each pixel P of the pixel unit 100 via a control line Lread. The pixel control unit 111 is controlled by the control unit 113 and controls the pixel P of the pixel unit 100.

[0019] The pixel control unit 111 generates signals for controlling the pixels P, such as a signal for controlling the transfer transistor of the pixel P, a signal for controlling the selection transistor, and a signal for controlling the reset transistor, and supplies the signals to each pixel P via a control line Lread. The pixel control unit 111 can control reading out pixel signals from each pixel P. The pixel control unit 111 can also be called 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 called a pixel control unit together.

[0020] The signal processing unit 112 is configured to be able to execute signal processing of the input pixel signal. The signal processing unit 112 is a signal processing circuit, and has, for example, a load circuit, an AD (Analog Digital) conversion circuit, a horizontal selection switch, etc. As an example, the load circuit is configured by a current source capable of supplying a current to the amplification transistor of the pixel P. The load circuit, together with the amplification transistor of the pixel P, configures, for example, a source follower circuit.

[0021] The signal processing unit 112 may have an amplifier circuit configured to amplify a signal read from the pixel P via the signal line VSL. The load circuit, the amplifier circuit, the AD conversion circuit, etc. are provided for each of the multiple signal lines VSL, 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.

[0022] A signal output from each pixel P selected and scanned by the pixel control unit 111 is input to a signal processing unit 112 via a signal line VSL. The signal processing unit 112 can perform signal processing such as AD conversion of the signal of the pixel P and CDS (Correlated Double Sampling). The signal of each pixel P transmitted through each signal line VSL is subjected to signal processing by the signal processing unit 112 and output to a processing unit 114.

[0023] 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, tone correction processing, etc.

[0024] 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, and the like, 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. The control unit 113 performs drive control of the pixel control unit 111, the signal processing unit 112, and the like, based on various timing signals (pulse signals, clock signals, and the like) generated by the timing generator.

[0025] The pixel section 100, the pixel control section 111, the signal processing section 112, and the like described above may be provided on one substrate. The pixel control section 111, the signal processing section 112, the control section 113, the processing section 114, and the like may be provided on one semiconductor substrate, or may be provided separately on multiple semiconductor substrates. The imaging device 1 may have a layered structure formed by stacking multiple substrates. Note that some or all of the signal processing section 112, the control section 113, and the processing section 114 may be integrally configured.

[0026] [Pixel configuration] 3 is a diagram for explaining an example of a circuit configuration of a pixel of the imaging device according to the first embodiment. The pixel P has a photoelectric conversion unit 12 (photoelectric conversion element) and a readout circuit 20. The photoelectric conversion unit 12 is configured to receive light and generate a signal. The readout circuit 20 is configured to be capable of outputting a signal based on charges photoelectrically converted. The readout circuit 20 can read out a pixel signal based on the charges photoelectrically converted by the photoelectric conversion unit 12.

[0027] The photoelectric conversion unit 12 is a light receiving unit (light receiving element) and is 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) and 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.

[0028] The read circuit 20 includes, for example, a transistor TRG, a floating diffusion FD, a transistor AMP, a transistor SEL, and a transistor RST. The transistors TRG, AMP, SEL, and RST are each a MOS transistor (MOSFET) having a gate, a source, and a drain terminal.

[0029] 3, the transistors TRG, AMP, SEL, and RST are each configured as an NMOS transistor. The transistors of the pixel P may be configured as PMOS transistors.

[0030] The transistor TRG is a transfer transistor and is configured to be able to transfer charges photoelectrically converted by 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 stored in the photoelectric conversion unit 12 to the floating diffusion FD.

[0031] The floating diffusion FD is an accumulation unit and is configured to be able to accumulate the transferred electric charge. The floating diffusion FD can accumulate the electric charge photoelectrically converted by the photoelectric conversion unit 12. The floating diffusion FD can also be said to be a retention unit capable of retaining the transferred electric charge. The floating diffusion FD accumulates the transferred electric charge and converts it into a voltage according to the capacity of the floating diffusion FD.

[0032] 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.

[0033] The gate of the transistor AMP is electrically connected to the floating diffusion FD, and the voltage converted by the floating diffusion FD is input to the gate of the transistor AMP. In the example shown in Figure 3, the drain of the transistor AMP is connected to a power supply line through which a power supply voltage VDD is supplied.

[0034] The source of the transistor AMP is connected to the signal line VSL via the transistor SEL. The transistor AMP is configured to generate a signal based on the charge stored 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 VSL.

[0035] The transistor SEL is configured to be capable of controlling the output of a pixel signal. The transistor SEL is electrically connected in series with the transistor AMP, for example, as shown in the example of FIG. 3. The transistor SEL is controlled by a signal SSEL and configured to be capable of outputting a signal from the transistor AMP to a signal line VSL. The transistor SEL is a selection transistor and can control the output timing of the pixel signal.

[0036] The transistor SEL is configured to be capable of outputting 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 VSL. The transistor SEL may be electrically connected in series between the transistor AMP and a power line to which a power supply voltage VDD is applied. Furthermore, the transistor SEL may be omitted as necessary.

[0037] 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.

[0038] 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. In the example shown in Fig. 3, 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 discharge the charge accumulated in the photoelectric conversion unit 12 via the transistor TRG.

[0039] The pixel control unit 111 (see FIG. 1) of the imaging device 1 supplies control signals to the gates of the transistors TRG, SEL, RST, etc. of each pixel P via the control line Lread described above, turning the transistors on (conducting) or off (non-conducting).

[0040] The multiple control lines Lread 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.

[0041] The readout circuit 20 may be configured to change the conversion efficiency (gain) when converting the charge into a voltage. For example, the readout circuit 20 may have a 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.

[0042] 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 is switched. The switching transistor can change the capacitance connected to the gate of the transistor AMP to change the conversion efficiency.

[0043] 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 VSL. The pixel control unit 111 can control the reading out of the pixel signal of each pixel P to the signal line VSL.

[0044] [Configuration of imaging device] Fig. 4 is a diagram showing an example of a planar configuration of an imaging device according to the first embodiment. Fig. 4 shows an example of an arrangement of pixels P of a pixel section 100 in the imaging device 1. The pixel P of the imaging device 1 has a light guide section 60 and a filter 25. The light guide section 60 is configured using a multi-layer (multiple stages) structure (for example, a first structure 51 and a second structure 52). Note that, of the first structure 51 and the second structure 52, only the first structure 51 is shown in Fig. 4.

[0045] The light guiding section 60 (light guiding member) has, for example, a first structure 51 and a second structure 52 which are nanostructures, and is configured to guide incident light to the photoelectric conversion section 12 side. The light guiding section 60 is a light guiding element (light guiding member) that utilizes metamaterial (metasurface) technology. In the imaging device 1, for example, as in the example shown in FIG. 4, the light guiding section 60 is provided for each pixel P or for each set of multiple pixels P.

[0046] The filter 25 is configured to selectively transmit light in a specific wavelength range from among 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).

[0047] The pixels P provided in the pixel section 100 of the imaging device 1 include, 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 pixels Pr, the pixels Pg, and the pixels Pb are repeatedly arranged.

[0048] The pixels Pr, Pg, and Pb are arranged according to a Bayer array, for example. In the pixel unit 100, 2×2 pixels each consisting of one pixel Pr, two pixels Pg, and one pixel Pb are repeatedly arranged. The pixel unit 100 has, for example, a pixel row in which the pixels Pg and Pr are alternately arranged, and a pixel row in which the pixels Pb and Pg are alternately arranged.

[0049] The pixels Pr, Pg, and Pb of the pixel unit 100 can generate an R component pixel signal, a G component pixel signal, and a B component pixel signal, respectively. The imaging device 1 can obtain RGB pixel signals. The arrangement of the pixels P is not limited to the above example, and can be set arbitrarily.

[0050] For example, the pixels Pr, Pg, and Pb may each be arranged in a 2×2 pixel unit. 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.

[0051] The filter 25 provided in the pixel P of the pixel unit 100 is not limited to a primary color (RGB) color filter, and may be a complementary color filter such as Cy (cyan), Mg (magenta), or Ye (yellow). A filter corresponding to W (white), that is, a filter that transmits light of all wavelengths of incident light, may be disposed. The filter 25 may be a filter that transmits infrared light.

[0052] In addition, the filter 25 may be omitted in the imaging device 1 as necessary. 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. Furthermore, the filter 25 may not be provided in pixels (referred to as white pixels, clear pixels, etc.) that receive white (W) light and perform photoelectric conversion.

[0053] 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 multi-layer 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 multi-layer 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 multi-layer wiring layer 95 are provided.

[0054] The optical layer 80 has a plurality of structural bodies (multiple stages) and is configured to guide incident light to the photoelectric conversion section 12 side. The optical layer 80 has a plurality of structural bodies (first structural body 51 and second structural body 52 in FIG. 5 ) that are provided so as to be stacked on each other. The optical layer 80 has, for example, a first layer 71 (first layer) in which the first structural body 51 is provided, and a second layer 72 (second layer) in which the second structural body 52 is provided. The optical layer 80 including the first layer 71 and the second layer 72 is provided so as to be stacked on the insulating layer 90.

[0055] The optical layer 80 is an optical element (optical member) that utilizes metamaterial (metasurface) technology. The first structure 51 and the second structure 52 each have, for example, a columnar (pillar) shape. The first structure 51 and the second structure 52 can be called a first metasurface element and a second metasurface element, respectively. The optical layer 80 can also be called a metasurface layer (or a metamaterial layer).

[0056] The first layer 71 of the optical layer 80 has a plurality of first structures 51 and a medium (first member 61) provided around the first structures 51. The second layer 72 has a plurality of second structures 52 and a medium (second member 62) provided around the second structures 52. The second layer 72 is provided by being stacked on the first layer 71. Each of the first structures 51 and the second structures 52 is, for example, a pillar (columnar member) and can be said to be a nanopillar.

[0057] The first structure 51 and the first member 61 are made of materials having refractive indexes different from each other. The second structure 52 and the second member 62 are made of materials having refractive indexes different from each other. The optical layer 80 may have a light guide section 60 including the first structure 51, the first member 61, the second structure 52, and the second member 62 for each pixel P or for each of a plurality of pixels P, as in the example shown in FIG. 5 .

[0058] 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 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. are provided on the surface 11S2 of the semiconductor layer 10.

[0059] The semiconductor layer 10 is composed of a semiconductor substrate, for example, a Si (silicon) substrate. The semiconductor layer 10 may be an SOI (silicon on insulator) substrate, a SiGe (silicon germanium) substrate, a SiC (silicon carbide) substrate, or the like. The semiconductor layer 10 may be composed of a III-V group compound semiconductor material, or may be formed using other semiconductor materials.

[0060] 5, a filter 25, an insulating layer 90, and the like 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 laminated on the semiconductor layer 10 in a thickness direction perpendicular to the surface 11S1 of the semiconductor layer 10. A multilayer 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 multilayer 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.

[0061] In the semiconductor layer 10, a plurality of photoelectric conversion units 12 (photoelectric conversion elements) are provided along a surface 11S1 and a surface 11S2 of the semiconductor layer 10. For example, a plurality of photoelectric conversion units 12 are embedded and formed in the semiconductor layer 10. The photoelectric conversion units 12 are provided between the surface 11S1 and the surface 11S2 of the semiconductor layer 10. The photoelectric conversion units 12 photoelectrically convert light 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.

[0062] The multi-layer wiring layer 95 is provided by being laminated on the semiconductor layer 10. The multi-layer wiring layer 95 includes, for example, a conductor film and an insulating film, and has a plurality of wirings and vias (VIA), etc. The multi-layer wiring layer 95 has a configuration in which a plurality of wirings are laminated via an insulating film serving as an interlayer insulating film (interlayer insulating layer). The multi-layer wiring layer 95 includes, for example, two or more layers of wirings, or three or more layers of wirings.

[0063] The wiring of the multi-layer wiring layer 95 is formed using a metal material such as aluminum (Al), copper (Cu), or tungsten (W). The wiring of the multi-layer 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.

[0064] The semiconductor layer 10 and the multilayer wiring layer 95 are provided with the above-mentioned readout circuit 20 (see FIG. 3), for example, for each pixel P or for each set of multiple pixels P. The above-mentioned pixel control unit 111, signal processing unit 112, control unit 113, processing unit 114, and the like (see FIG. 1) may be provided on a substrate separate from the semiconductor layer 10, or in the semiconductor layer 10 and the multilayer wiring layer 95.

[0065] The insulating layer 90 is provided between the optical layer 80 in which the light guide section 60 is provided, 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 in which the filter 25 is provided. The insulating layer 90 is formed using an insulating film such as an oxide film, a nitride film, or an oxynitride film, for example. The insulating layer 90 is formed using an insulating material such as silicon oxide (SiO), silicon nitride (SiN), or aluminum oxide (AlO).

[0066] The insulating layer 90 may be made of a material with a low refractive index, such as silicon oxide, or may be made of other materials that transmit 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. The optical layer 80 may be configured to include the insulating layer 90.

[0067] 5, the imaging device 1 has a separator 30. The separator 30 is provided between adjacent photoelectric conversion units 12 to separate the photoelectric conversion units 12. At least a portion of the separator 30 is provided at the boundary between adjacent pixels P (or photoelectric conversion units 12). The separator 30 is formed using, for example, a trench.

[0068] The separation portion 30 may be formed in the semiconductor layer 10 so as to surround the photoelectric conversion portion 12 of each pixel P. The separation portion 30 may be provided so as to penetrate the semiconductor layer 10. That is, the separation portion 30 may be formed so as to reach the surface 11S2 of the semiconductor layer 10. The separation portion 30 may also be referred to as a pixel separation portion or a pixel separation wall.

[0069] An insulating film, such as a silicon oxide film, a silicon nitride film, an aluminum oxide film, or the like, is provided in the trench of the isolation unit 30. Polysilicon, a metal material, other insulating materials, or the like may be embedded in the trench of the isolation unit 30. The isolation unit 30 may be configured of a semiconductor region (a p-type semiconductor region or an n-type semiconductor region) formed by ion implantation.

[0070] The separation section 30 may be formed using other insulating materials having a low refractive index. A gap (cavity) may be provided in the trench of the separation section 30. In the imaging device 1, the separation section 30 is provided to suppress leakage of electric charges photoelectrically converted in the photoelectric conversion section 12 of the pixel P to the surrounding pixels P (or the photoelectric conversion section 12). In addition, leakage of unnecessary light to the surrounding pixels P can be suppressed, and for example, color mixing can be suppressed.

[0071] 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. As an example, the fixed charge film and the antireflection film are made of a metal compound (metal oxide, metal nitride, etc.) and can also be called a metal compound layer.

[0072] The fixed charge film and the 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. As an 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.

[0073] 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.

[0074] The anti-reflection film is, for example, made of a metal oxide such as hafnium oxide or tantalum oxide. The anti-reflection film is provided on the surface 11S1 side of the semiconductor layer 10 to reduce (suppress) reflection. The anti-reflection film is provided, for example, so as to be laminated with the fixed charge film. The anti-reflection 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.

[0075] 5, the optical layer 80 of the imaging device 1 is provided above the photoelectric conversion section 12. The optical layer 80 has a first layer 71 in which the first structures 51 are arranged, and a second layer 72 in which the second structures 52 are arranged. The second layer 72 is laminated on the first layer 71. The light guiding section 60 of the optical layer 80 has the first structures 51 in the first stage and the second structures 52 in the second stage.

[0076] Light from a subject, which is 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 first structure 51 and the second structure 52 of the light guiding unit 60. For example, the first structure 51 and the second structure 52 are each a structure having a size equal to or smaller than a predetermined wavelength of the incident light.

[0077] The optical layer 80 (or the light guide section 60) has first structures 51 and second structures 52 which are nanostructures, and is configured to guide light incident from above in Fig. 5 to the photoelectric conversion section 12 side. The first structures 51 and the second structures 52 each 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. Note that each of the first structures 51 and the second structures 52 may have a size equal to or smaller than the wavelength range of infrared light.

[0078] The first structures 51 and the second structures 52 are each, for example, a columnar (pillar-shaped) structure. As an example, each of the first structures 51 and the second structures 52 has a cylindrical shape. The multiple first structures 51 are arranged to be aligned with each other in the X-axis direction (or Y-axis direction) with a part of the first member 61 in between.

[0079] The second structures 52 are arranged to be aligned with each other in the X-axis direction (or Y-axis direction) with a part of the second member 62 in between. The shapes of the first structures 51 and the second structures 52 can be changed as appropriate, and may each be a circle or a rectangle in a plan view. The shapes of the first structures 51 and the second structures 52 may each be an ellipse, a polygon, a cross, or another shape.

[0080] The first member 61 is provided so as to fill the periphery of the first structure 51. The first member 61 is formed, for example, in the first layer 71 so as to fill the spaces between the multiple adjacent first structures 51. The second member 62 is provided so as to fill the periphery of the second structure 52. The second member 62 is formed, for example, in the second layer 72 so as to fill the spaces between the multiple adjacent second structures 52.

[0081] The first structure 51 is provided in the first member 61, and can also be said to be disposed so as to replace a part of the first member 61. The second structure 52 is provided in the second member 62, and can also be said to be disposed so as to replace a part of the second member 62. The first member 61 and the second member 62 can also be said to be medium layers or protective layers (protective members).

[0082] The light guiding unit 60 utilizes the first structure 51 and the second structure 52, which are nanostructures, to propagate light toward the photoelectric conversion unit 12. Each of the first structure 51 and the second structure 52 is also called a meta-atom, a nano-atom, a nano-post, a metasurface structure, a microstructure, etc. The light guiding unit 60 is an optical element (optical member) that guides (propagates) light.

[0083] The light guide unit 60 is configured as, for example, a light guide element capable of providing a phase delay to incident light and guiding the light. In the optical layer 80, as an example, a plurality of first structures 51 and second structures 52 are arranged so as to provide a desired phase profile to the incident light. For example, the size, number of arrangements, arrangement interval (pitch), etc. of each of the first structures 51 and the second structures 52 are determined so that light in a wavelength band to be detected is condensed to the photoelectric conversion unit 12.

[0084] 6A and 6B are diagrams showing an example of a planar configuration of a light guiding section of an imaging device according to the first embodiment. Fig. 6A shows an example of a configuration of a second layer 72 of a light guiding section 60, and Fig. 6B shows an example of a configuration of a first layer 71 of a light guiding section 60. As an example, a plurality of first structures 51 and a plurality of second structures 52 are two-dimensionally arranged in the X-axis direction and the Y-axis direction in a planar view, as in the example shown in Figs. 6A and 6B.

[0085] The width of the first structures 51 in the X-axis direction (or the Y-axis direction) and the width of the second structures 52 in the X-axis direction (or the Y-axis direction) may each be, for example, equal to or less than the wavelength range of visible light. As shown in Fig. 6A, the width (diameter) W2 of the second structures 52 may be, for example, 80 nm to 800 nm. Also, as shown in Fig. 6B, the width W1 of the first structures 51 may be, for example, 80 nm to 800 nm.

[0086] In the first layer 71 of the imaging device 1, for example, a plurality of first structures 51 are arranged at intervals equal to or less than a predetermined wavelength of incident light. In addition, in the second layer 72, a plurality of second structures 52 may be arranged at intervals equal to or less than the predetermined wavelength of incident light. As an example, a plurality of first structures 51 (or a plurality of second structures 52) are provided at intervals equal to or less than the wavelength range of visible light in the X-axis direction and the Y-axis direction. Note that in the pixel P, a plurality of first structures 51 (or a plurality of second structures 52) may be arranged at intervals equal to or less than the wavelength range of infrared light.

[0087] In the imaging device 1, at least some of the second structures 52 among the multiple second structures 52 are provided in contact with the first structures 51. For example, as in the example shown in Fig. 5, some of the second structures 52 among the multiple second structures 52 in the second layer 72 are provided in contact with the first structures 51. In the example shown in Fig. 5, some of the second structures 52 are disposed on the first structures 51 and are in contact with the first structures 51.

[0088] In this disclosure, "in contact" includes direct contact and contact via a natural oxide film or the like. "Second structure 52 and first structure 51 are in contact" includes a case where a natural oxide film is present, and includes a case where second structure 52 is in contact with first structure 51 via a thin natural oxide film. "In contact" indicates that there is no etching stopper film between the structures.

[0089] The first structures 51 and the second structures 52 are provided so as to be in contact with each other. In the example shown in Fig. 5, upper ends (tips) of some of the first structures 51 are in contact with lower ends (bottoms) of the second structures 52. The imaging device 1 has a layered structure in which the first structures 51 and the second structures 52 are layered. The light guiding section 60 may have a structure in which the second structures 52 as the second metasurface element are directly layered on the first structures 51 as the first metasurface element.

[0090] In the imaging device 1, the first member 61 and the second member 62 are provided so as to be in contact with each other. The second member 62 is provided so as to be in contact with the first member 61, for example, as in the example shown in FIG. The second member 62 is directly stacked on the first member 61 and disposed so as to be in contact with the first member 61.

[0091] The first structure 51 has a refractive index different from that of an adjacent medium. In the example shown in FIG. 5 etc., the first structure 51 has a refractive index different from that of a first member 61. The first structure 51 has a refractive index different from that of the medium surrounding the first structure 51, i.e., the first member 61. The first member 61 can also be said to be a first material layer having a refractive index different from that of the first structure 51.

[0092] The second structure 52 has a refractive index different from that of the adjacent medium. In the example shown in FIG. 5 etc., the second structure 52 has a refractive index different from that of the second member 62. The second structure 52 has a refractive index different from that of the medium surrounding the second structure 52, i.e., the second member 62. The second member 62 can also be said to be a second material layer having a refractive index different from that of the second structure 52.

[0093] The first structure 51 has, for example, a refractive index higher than that of the first member 61. The first structure 51 may be made of a material having a refractive index higher than that of the first member 61. Moreover, the second structure 52 has, for example, a refractive index higher than that of the second member 62. The second structure 52 may be made of a material having a refractive index higher than that of the second member 62.

[0094] The first structure 51 and the second structure 52 may be configured using the same material. The second structure 52 is configured, for example, using the same material as the first structure 51 and is formed on the first structure 51. The first structure 51 and the second structure 52 may each be configured using an inorganic material, for example, an oxide film. Furthermore, each of the first structure 51 and the second structure 52 may be configured by an oxide film containing titanium (Ti).

[0095] The first structure 51 and the second structure 52 are configured using titanium oxide (TiO) as an example. As another example, the first structure 51 and the second structure 52 are configured using a nitride film such as silicon nitride (SiN) or silicon oxynitride (SiON). The first structure 51 and the second structure 52 may be formed using silicon, polysilicon (Poly-Si), amorphous silicon (a-Si), germanium (Ge), or the like.

[0096] The first structure 51 and the second structure 52 may be made of a simple substance, an oxide, a nitride, an oxynitride, or a composite of titanium (Ti), hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), indium (In), niobium (Nb), etc. The first structure 51 and the second structure 52 may be made of other metal compounds (metal oxides, metal nitrides, etc.).

[0097] Furthermore, the first structure 51 and the second structure 52 may be configured using GaP, GaN, GaAs, or the like. The first structure 51 and the second structure 52 may be formed using silicon carbide (SiC) or other silicon compounds. The first structure 51 and the second structure 52 may be configured using air. For example, at least one of the first structure 51 and the second structure 52 may be configured to include air (voids).

[0098] The first member 61 and the second member 62 are made of the same material. For example, the first member 61 and the second member 62 are made of inorganic materials such as oxides, nitrides, and oxynitrides. The first member 61 and the second member 62 may be formed of, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon oxide carbide, or other silicon compounds. The first member 61 and the second member 62 may be made of TEOS.

[0099] The first member 61 and the second member 62 may be made of the same organic material. The first member 61 and the second member 62 may be made of a siloxane resin, a styrene resin, an acrylic resin, or the like. The first member 61 and the second member 62 may be made of a material in which any of these resins contains fluorine. The first member 61 and the second member 62 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 materials of the first structure 51, the second structure 52, the first member 61, and the second member 62 can be selected depending on the refractive index difference with the surrounding medium, the wavelength range of the incident light to be measured, etc. Note that a part of the first structure 51, the second structure 52, the first member 61, and the second member 62 may be made of air.

[0101] 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 refractive index difference between the first structure 51 and the second structure 52 and the medium surrounding them. The light guiding section 60 can adjust the propagation direction of the light by imparting a phase delay to the incident light by, for example, the second structure 52 and the second member 62, and the first structure 51 and the first member 61.

[0102] The materials (optical constants of each material) of the first structure 51, the second structure 52, the first member 61, and the second member 62, the sizes (width (diameter), height, etc.) and pitch (disposition interval) of the first structure 51 and the second structure 52, etc. are determined so that light of a desired wavelength range among incident light from the measurement target travels in a desired direction. For example, the materials (refractive index), dimensions, pitch, and materials (refractive index) of the first structure 51 and the second structure 52, the materials (refractive index) of the first member 61 and the second member 62, etc. may be set.

[0103] As an example, in the imaging device 1, the material, size, arrangement number, and the like of the first structures 51 and second structures 52 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 first structures 51 and second structures 52 of the light guide units 60 of the pixels Pr, Pg, and Pb may be formed so as to have different sizes (e.g., width, height), arrangement positions, and the like.

[0104] The optical layer 80 (or the light guide section 60) may be configured, for example, as a spectroscopic section (spectroscopic element) capable of splitting incident light. The optical layer 80 (or the light guide section 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 section 60) may also be referred to as an optical element configured to redirect light.

[0105] 5, the imaging device 1 is provided with an antireflection film 45 and a stopper film 46. The light guide section 60 of each pixel P may have the antireflection film 45 and the stopper film 46. The antireflection film 45 (antireflection film) is provided, for example, on the side of the second structure 52 where light is incident, and is located on the second structure 52. The antireflection film 45 is provided, for example, as shown in FIG. 5, so as to cover the multiple second structures 52, and reduces (suppresses) reflection.

[0106] The anti-reflection film 45 is made of a silicon compound such as silicon nitride (SiN) or silicon oxide (SiO). The anti-reflection film 45 may be made of a metal compound or other materials. The anti-reflection film 45 may be made by stacking a plurality of films.

[0107] The stopper film 46 is provided, for example, between the first structure 51 and the insulating layer 90. The stopper film 46 serves as an etching stopper film (stopper layer) during manufacture of the imaging device 1. By providing the stopper film 46, it is possible to improve the processing controllability of the first structure 51. The stopper film 46 can also be called an etching prevention film (or an etching suppression film).

[0108] The stopper film 46 is, for example, a single layer film made of one of silicon nitride (SiN), silicon oxynitride (SiON), hafnium oxide (HfO), aluminum oxide (AlO), etc., or a laminated film made of two or more of these. The stopper film 46 may be formed using other materials. The insulating layer 90 may be configured to include the stopper film 46.

[0109] As described above, light from a subject to be measured is incident on each pixel P of the imaging device 1 through the optical layer 80. Each pixel P can receive light incident through the second structure 52 and the first structure 51 of the light guiding section 60 and generate a pixel signal. The imaging device 1 can generate image data indicating an image of the subject using the pixel signal obtained by photoelectric conversion in each pixel P.

[0110] Furthermore, for example, the imaging device 1 can generate image data relating to the distance to an object (distance image data) using the pixel signal of each pixel. In this embodiment, the light guiding section 60 having the first structure 51 and the second structure 52 can appropriately guide light to the photoelectric conversion section 12. The multiple stages of metasurface elements can efficiently guide light in any wavelength range to the photoelectric conversion section 12.

[0111] In the imaging device 1, as described above, the first structure 51 is provided in contact with the second structure 52. This makes it possible to suppress the generation of unnecessary reflected light and improve quantum efficiency (QE). Compared to the case where an etching stopper film is provided between the first structure 51 and the second structure 52, the number of interfaces can be reduced, making it possible to prevent an increase in reflectance.

[0112] In the imaging device 1, the second structure 52 is provided in contact with the first structure 51, so that it is possible to suppress a decrease in light utilization efficiency. It is possible to improve sensitivity to incident light. It is also possible to suppress the occurrence of flare and prevent a decrease in image quality. It is possible to realize a light detection device having good optical characteristics.

[0113] In the present embodiment, the first structure 51 and the second structure 52 are configured using the same material. By using the same material for the first structure 51 and the second structure 52, for example, it is possible to suppress the occurrence of unnecessary reflected light. Also, it is possible to improve the adhesion between the first layer 71 and the second layer 72.

[0114] Fig. 7 is a diagram for explaining another example of the configuration of the imaging device according to the first embodiment. Fig. 8 is a diagram for explaining another example of the configuration of the light guiding section of the imaging device. The optical layer 80 and the light guiding section 60 of the imaging device 1 may have the structures shown in Figs. 7 and 8.

[0115] In the imaging device 1, the first structure 51 and the second structure 52 of the light guiding section 60 may have different shapes. By configuring the light guiding section 60 with the first structure 51 and the second structure 52 having different shapes, it is possible to improve the design freedom. It is possible to improve the controllability of light.

[0116] The first structures 51 and the second structures 52 may have different lengths in the stacking direction of the first layer 71 and the second layer 72 (the Z-axis direction in FIGS. 7 and 8). As an example, the first structures 51 and the second structures 52 may be formed such that the length (height) of the first structures 51 in the Z-axis direction is greater than the length of the second structures 52. Furthermore, the length in the Z-axis direction of at least some of the second structures 52 among the multiple second structures 52 may be greater than the length of the first structures 51.

[0117] 8, the lower end portions A2 of some of the second structures 52 among the plurality of second structures 52 are located below the upper end portions A1 of the first structures 51. The lower end portions A2 (bottom portions) of the second structures 52 are located lower than the upper end portions A1 (tip portions) of the first structures 51. The second structures 52 can be formed up to a region deeper than the upper end portions A1 of the first structures 51. By configuring the imaging device 1 in this manner, it is possible to improve the adhesion between the first layer 71 and the second layer 72. It is possible to improve the reliability of the imaging device 1.

[0118] 7 or 8, the first structures 51 may be provided such that the width (length) of the first structures 51 on the second structures 52 side is larger than the width of the first structures 51 on the side opposite to the second structures 52 side. The first structures 51 may be formed such that the width of an upper end portion (tip portion) of the first structures 51 is larger (thicker) than the width of a lower end portion (bottom portion) of the first structures 51.

[0119] The width of the first structure 51 in the X-axis direction (or the Y-axis direction) increases, for example, as it approaches the second structure 52. It can also be said that the width (thickness) of the first structure 51 in the X-axis direction (or the Y-axis direction) decreases as it approaches the stopper film 46 (or the insulating layer 90).

[0120] The width (length) of the first structure 51 in the X-axis direction (or Y-axis direction) may monotonically increase depending on the distance from the stopper film 46 in a predetermined section (range). In the example shown in Fig. 7, the width of the first structure 51 gradually increases (widens) from the lower part to the upper part of the first structure 51. It can also be said that the first structure 51 has a portion whose width increases (widens) as it approaches the second structure 52.

[0121] The first structure 51 may have a recess B1 as in the example shown in Fig. 7 or 8. The first structure 51 may have a recess B1 (groove portion) provided on the second structure 52 side. The first structure 51 having the recess B1 can be formed by using, for example, lithography and etching. The recess B1 is also called a recess (groove).

[0122] The recess B1 may be provided in the upper portion of the first structure 51, as shown in FIG. 7 or 8. The recess B1 is, for example, a portion that is formed relatively shallow, and may also be called a recess. The depth (height) of the recess B1 may be, for example, several nm or less. The depth d1 of the recess B1 shown in FIG. 8 may be, for example, about 5 nm.

[0123] The second structure 52 may be provided in contact with the recessed portion B1 of the first structure 51. In the example shown in Fig. 7 and Fig. 8, a portion of the second structure 52 is provided in the recessed portion B1 of the first structure 51. A portion of the second structure 52 is disposed so as to be embedded in the recessed portion B1, for example.

[0124] By providing a part of the second structure 52 in the recess B1 of the first structure 51, it is possible to prevent an increase in the reflectance of the optical layer 70. It is possible to reduce reflection in the light guiding section 60 and improve quantum efficiency. It is possible to suppress the occurrence of flare and prevent deterioration in image quality.

[0125] The second structure 52 may have a recess B2. The second structure 52 may have a recess B2 (groove) provided on the side opposite to the first structure 51. The recess B2 is also called a recess. The second structure 52 having the recess B2 can be formed by using, for example, lithography and etching.

[0126] The recess B2 may be provided in an upper portion of the second structure 52. The recess B2 may be, for example, a portion that is formed relatively shallow and may be called a recessed portion. The depth (height) of the recess B2 may be, for example, several nm or less. The depth d2 of the recess B2 shown in FIG. 8 may be, for example, about 5 nm.

[0127] The antireflection film 45 may be provided in contact with the recessed portion B2 of the second structure 52. In the example shown in Fig. 7 and Fig. 8, a portion of the antireflection film 45 is provided in the recessed portion B2 of the second structure 52. A portion of the antireflection film 45 is disposed so as to be embedded in the recessed portion B2, for example.

[0128] By providing a part of the antireflection film 45 in the recess B2 of the second structure 52, an increase in reflectance can be prevented and quantum efficiency can be improved. It is possible to suppress the occurrence of flare and prevent a decrease in image quality.

[0129] The shapes of the recess B1 of the first structure 51 and the recess B2 of the second structure 52 are not limited to the example shown in Fig. 8. The recess B1 and the recess B2 may have a rounded shape as in the example shown in Fig. 9A or 9B. The recess B1 of the first structure 51 and the recess B2 of the second structure 52 may each have a rounded portion.

[0130] 10, the second structure 52 may have a protrusion C2. The second structure 52 may have a protrusion C2 (projection) provided on the side surface of the second structure 52 on the first structure 51 side. The protrusion C2 of the second structure 52 may be formed by utilizing side etching, and may also be called a side etch portion. The protrusion C2 may be provided along the interface between the first layer 71 and the second layer 72.

[0131] The protrusion C2 of the second structure 52 is formed, for example, along the boundary between the first layer 71 and the second layer 72, and protrudes in a direction perpendicular to the stacking direction of the first layer 71 and the second layer 72. The protrusion C2 is a protruding structural part, and can also be called a protrusion. In the imaging device 1, the provision of the protrusion C2 can improve the adhesion between the first layer 71 and the second layer 72. The reliability of the imaging device 1 can be improved.

[0132] In the imaging device 1, the first structure 51 may have a seam. When the first structure 51 has a seam, peeling of the first structure 51 caused by stress concentration can be prevented. It becomes possible to prevent deterioration of the characteristics of the light guiding section 60. Note that the second structure 52 may be configured to have a seam. It becomes possible to suppress peeling of the second structure 52 and deterioration of the characteristics of the light guiding section 60.

[0133] 8 and the like may have a thickness d11 (length) in the Z-axis direction of 10 nm to 2000 nm, for example. Also, a thickness d12 in the Z-axis direction of the second structure 52 may be 10 nm to 2000 nm. The thickness d11 of the first structure 51 and the thickness d12 of the second structure 52 may each be, for example, several hundred nm or less, or several tens of nm or less.

[0134] The thickness (height) of the first structures 51 may be different from the thickness of the second structures 52, or may be substantially the same as the thickness of the second structures 52. The film thickness (thickness) d13 of the antireflection film 45 may be, for example, within a range of 10 nm to 3000 nm. The film thickness d14 of the stopper film 46 may be, for example, 1 nm to 1000 nm.

[0135] 11A to 11D are diagrams for explaining an example of a method for manufacturing the light guide section of the imaging device according to the first embodiment. First, as shown in Fig. 11A, a hard mask 103, for example, an a-Si film (amorphous silicon film), is formed on the first structure 51 and the first member 61. Then, as shown in Fig. 11B, the hard mask 103 is processed by etching.

[0136] Next, as shown in Fig. 11C, the second member 62 is formed on the first layer 71, and then the hard mask 103 is peeled off. Then, as shown in Fig. 11D, the second structure 52 is embedded in the second member 62, and then the anti-reflection film 45 is formed on the second structure 52 and the second member 62. By the manufacturing method as described above, the light guide section 60 shown in Fig. 7 etc. can be manufactured. Note that the above-mentioned manufacturing method is merely one example, and other manufacturing methods may be adopted.

[0137] [Actions and Effects] The photodetector according to the present embodiment includes a first layer (first layer 71) having a first medium (first member 61) that is provided around the first structures and has a refractive index different from that of the first structures, a second layer (second layer 72) that is stacked on the first layer and has a second medium (second member 62) that is provided around the second structures and has a refractive index different from that of the second structures, and a photoelectric conversion element (photoelectric conversion section 12) that photoelectrically converts light incident through the second layer and the first layer. The second structures are made of the same material as the first structures. The second structures include a second structure that is in contact with the first structures.

[0138] In the photodetection device (imaging device 1) according to this embodiment, a first layer 71 having a plurality of first structures 51 and a second layer 72 having a plurality of second structures 52 are provided. The plurality of second structures 52 includes a second structure 52 in contact with the first structure 51. This makes it possible to suppress the occurrence of unnecessary reflected light. It becomes possible to realize a photodetection device capable of improving characteristics with respect to incident light.

[0139] (2. Modifications) In the above-mentioned embodiment, the configuration example of the light detection device has been described, but the configuration of the light detection device (imaging device) is not limited to the above-mentioned example. For example, the optical layer 80 may have a laminated structure of three layers, or four or more layers. The light guide section 60 may be configured to include, for example, three or more stages of nanostructures, or four or more stages.

[0140] Fig. 12 is a diagram for explaining a configuration example of an imaging device according to a modified example of the present disclosure. As in the example shown in Fig. 12, the optical layer 80 may have a first layer 71 (first level) in which the first structures 51 are provided, a second layer 72 (second level) in which the second structures 52 are provided, a third layer 73 (third level) in which the third structures 53 are provided, and a fourth layer 74 (fourth level) in which the fourth structures 54 are provided. The first structures 51 to the fourth structures 54 may be formed using the same material, for example.

[0141] For example, a fourth layer 74, a third layer 73, a second layer 72, and a first layer 71 are provided from the light incident side. The first layer 71 to the fourth layer 74 are provided by stacking without an etching stopper film therebetween. This makes it possible to reduce the number of interfaces and reduce reflection in the light guiding section 60. It is possible to realize a photodetector with good performance. In the case of this modification, the same effects as those of the above-mentioned embodiment can be obtained.

[0142] <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, and the like. The light guide section 60 (or the optical layer 80) configured using the above-mentioned nanostructure is applicable to various optical elements (optical members). In the following, the same components as those in the above-mentioned embodiment are given the same reference numerals, and the description will be omitted as appropriate.

[0143] 13 and 14 are diagrams for explaining a configuration example of an optical element according to a second embodiment of the present disclosure. The optical element 200 has a substrate 120 and an optical layer 80. As an example, the optical layer 80 includes a first layer 71 having a plurality of first structures 51, and a second layer 72 having a plurality of second structures 52. The optical element 200 is an optical element (optical member) configured using the first structures 51 and the second structures 52, which are nanostructures, and can be configured as a metalens (metamaterial lens).

[0144] 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 first structure 51 (or the second structure 52). 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 be made of another material that transmits the light to be measured.

[0145] As shown in Fig. 13, the substrate 120 has a surface 12S1 and a surface 12S2 that face each other. 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. 13 or 14, the optical layer 80 including a plurality of first structures 51 and a plurality of second structures 52 is formed on the surface 12S1 of the substrate 120.

[0146] The optical layer 80 including the first structure 51 and the second structure 52 may be provided on the side opposite to the side where light is incident on the substrate 120 (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.

[0147] The second structure 52 may have a size or shape different from that of the first structure 51. The first structure 51 may have a recess B1. A part of the second structure 52 may be provided so as to contact the recess B1 of the first structure 51. Furthermore, the second structure 52 may have a recess B2. A part of the anti-reflection film 45 may be provided so as to contact the recess B2 of the second structure 52. Note that the shapes, numbers, arrangements, etc. of the first structure 51 and the second structure 52 are not limited to the examples shown in the figures and can be changed as appropriate.

[0148] The optical element 200 may be configured as, for example, a lens that collects light, a lens that diffuses light, or the like. The optical element 200 may also be configured as a splitter that separates 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.

[0149] [Actions and Effects] The optical element according to the present embodiment includes a first layer (first layer 71) having a plurality of first structures (for example, first structures 51) arranged to be aligned in a first direction (for example, the X-axis direction), a first medium (first member 61) arranged around the first structures and having a refractive index different from that of the first structures, a plurality of second structures (second structures 52) arranged to be aligned in the first direction, and a second layer (second layer 72) having a second medium (second member 62) arranged around the second structures and having a refractive index different from that of the second structures, and laminated on the first layer. The second structures are made of the same material as the first structures. The plurality of second structures includes a second structure in contact with the first structures.

[0150] In the optical element (optical element 200) according to the present embodiment, a first layer 71 having a plurality of first structures 51 and a second layer 72 having a plurality of second structures 52 are provided. The plurality of second structures 52 includes a second structure 52 in contact with the first structure 51. This makes it possible to improve the characteristics with respect to incident light. It becomes possible to realize an optical element having good optical characteristics.

[0151] <3. Application Examples> The imaging device 1 and the like can be applied to any type of electronic device equipped with an imaging function, for example, a camera system such as a digital still camera or a video camera, a mobile phone equipped with an imaging function, etc. Fig. 15 shows a schematic configuration of an electronic device 1000.

[0152] 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.

[0153] 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 to the DSP circuit 1002 as a pixel signal.

[0154] The DSP circuit 1002 is a signal processing circuit that processes a signal supplied from the imaging device 1. The DSP circuit 1002 outputs image data obtained by processing the signal from the imaging device 1. The frame memory 1003 temporarily holds the image data processed by the DSP circuit 1002 on a frame-by-frame basis.

[0155] The display unit 1004 is, for example, 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 in a recording medium such as a semiconductor memory or a hard disk.

[0156] The operation unit 1006, in response to an operation by a user, outputs operation signals for various functions of the electronic device 1000. The power supply unit 1007 appropriately supplies various types of power to the DSP circuit 1002, the frame memory 1003, the display unit 1004, the recording unit 1005, and the operation unit 1006 as operating power sources to these power sources.

[0157] <4. Application Examples> (Example of application to moving objects) 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 moving body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, a robot, etc.

[0158] FIG. 16 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a moving object control system to which the technology according to the present disclosure can be applied.

[0159] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 16, 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, as functional configurations of the integrated control unit 12050, a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053 are illustrated.

[0160] 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.

[0161] The body system control unit 12020 controls the operation of various devices mounted on 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 head lamps, back lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals of various switches transmitted from a portable device that replaces a key may be input to the body system control unit 12020. The body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, and the like of the vehicle.

[0162] 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 an image outside the vehicle and receives the captured image. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for a person, a car, an obstacle, a sign, or characters on a road surface, based on the received image.

[0163] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according 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.

[0164] 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.

[0165] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the outside-of-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output a control command 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 inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0166] 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 the driver's operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle acquired by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0167] 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-vehicle 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-vehicle information detection unit 12030, and perform cooperative control for the purpose of preventing glare, such as switching from high beams to low beams.

[0168] The audio / video output unit 12052 transmits at least one output signal of audio and video to an output device capable of visually or audibly notifying information to passengers in the vehicle or the outside of the vehicle. In the example of Fig. 16, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as the output device. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

[0169] FIG. 17 is a diagram showing an example of the installation position of the imaging unit 12031.

[0170] In FIG. 17, a vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as an imaging unit 12031.

[0171] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the upper part of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The images of the front acquired by the imaging units 12101 and 12105 are mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

[0172] 17 shows an example of the imaging ranges of the imaging units 12101 to 12104. An 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 an imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, an overhead image of the vehicle 12100 viewed from above is obtained by superimposing the image data captured by the imaging units 12101 to 12104.

[0173] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera made up of a plurality of imaging elements, or may be an imaging element having pixels for detecting a phase difference.

[0174] For example, the microcomputer 12051 can extract, as a preceding vehicle, a three-dimensional object that is the closest three-dimensional object on the travel path of the vehicle 12100 and travels at a predetermined speed (for example, 0 km / h or more) in approximately the same direction as the vehicle 12100, by calculating the distance to each three-dimensional object in the imaging ranges 12111 to 12114 and the change over time of this distance (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. Furthermore, the microcomputer 12051 can set a vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including follow-up stop control) and automatic acceleration control (including follow-up start control). In this way, cooperative control can be performed for the purpose of automatic driving that travels autonomously without relying on the driver's operation.

[0175] For example, the microcomputer 12051 classifies and extracts three-dimensional object data on 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. Then, the microcomputer 12051 determines a collision risk indicating 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.

[0176] At least one of the imaging 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 or not a pedestrian is present in the captured images of the imaging units 12101 to 12104. The recognition of such a pedestrian is performed, for example, by a procedure of extracting feature points in the captured images of the imaging units 12101 to 12104 as infrared cameras, and a procedure of performing pattern matching processing on a series of feature points that indicate the contour of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

[0177] 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 imaging unit 12031 among the configurations described above. Specifically, for example, the imaging device 1 or the like can be applied to the imaging unit 12031. By applying the technology according to the present disclosure to the imaging unit 12031, it becomes possible to obtain a high-definition captured image. It becomes possible to perform high-precision control using the captured image in the mobile object control system.

[0178] (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.

[0179] FIG. 18 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.

[0180] 18 shows a state in which an operator (doctor) 11131 is 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.

[0181] 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 illustrated example, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may be configured as a so-called flexible scope having a flexible lens barrel.

[0182] 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 observation target in 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.

[0183] An optical system and an image sensor are provided inside the camera head 11102, and reflected light (observation light) from an observation target is collected on the image sensor by the optical system. 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 an observation image. The image signal is transmitted to a camera control unit (CCU) 11201 as RAW data.

[0184] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and performs overall control of 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), for displaying an image based on the image signal.

[0185] 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.

[0186] 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 an operation site or the like.

[0187] 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 irradiated light, magnification, focal length, etc.) of the endoscope 11100.

[0188] 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 sends gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity for the purpose of securing the field of view of the endoscope 11100 and securing the working space of the surgeon. The recorder 11207 is a device capable of recording various information related to the surgery. The printer 11208 is a device capable of printing various information related to the surgery in various formats such as text, image, or graph.

[0189] The light source device 11203 that supplies irradiation light to the endoscope 11100 when photographing the surgical site can be composed of a white light source composed of, for example, an LED, a laser light source, or a combination of these. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so that the white balance of the captured image can be adjusted in the light source device 11203. In this case, it is also possible to capture images corresponding to each of the RGB colors in a time-division manner by irradiating the observation object with laser light from each of the RGB laser light sources in a time-division manner and controlling the driving of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter to the image sensor.

[0190] The light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. The driving of the image sensor of the camera head 11102 may be controlled in synchronization with the timing of the change in the light intensity to obtain images in a time-division manner, and the images may be synthesized to generate an image with a high dynamic range that is free of so-called blackout and whiteout.

[0191] The light source device 11203 may be configured to supply light of a predetermined wavelength band corresponding to the special light observation. In the special light observation, for example, by utilizing the wavelength dependency of light absorption in body tissue, a narrow band light is irradiated compared to the irradiated light (i.e., white light) during normal observation, and a predetermined tissue such as blood vessels on the mucous membrane surface is photographed with high contrast, so-called narrow band imaging is performed. Alternatively, in the special light observation, a fluorescent observation may be performed in which an image is obtained by fluorescence generated by irradiating an excitation light. In the fluorescent observation, it is possible to irradiate an excitation light to a body tissue and observe the fluorescence from the body tissue (autofluorescence observation), or to locally inject a reagent such as indocyanine green (ICG) into the body tissue and irradiate the body tissue 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.

[0192] FIG. 19 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0193] 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 by a transmission cable 11400 so as to be able to communicate with each other.

[0194] 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 configured by combining a plurality of lenses including a zoom lens and a focus lens.

[0195] The imaging unit 11402 is composed of an imaging element. The imaging element constituting the imaging unit 11402 may be one (so-called single-plate type) or multiple (so-called multi-plate type). When the imaging unit 11402 is composed of a multi-plate 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 the image 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. By performing 3D display, the surgeon 11131 can more accurately grasp the depth of the biological tissue in the surgical site. Note that when the imaging unit 11402 is composed of a multi-plate type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0196] 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 behind the objective lens.

[0197] 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 appropriately adjusted.

[0198] The communication unit 11404 is configured by a communication device for transmitting and receiving various 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.

[0199] 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 capturing the image, and / or information specifying the magnification and focus of the captured image.

[0200] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by a user, or may be automatically set by the control unit 11413 of the CCU 11201 based on an 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.

[0201] 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.

[0202] The communication unit 11411 is configured with 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.

[0203] 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.

[0204] The image processing unit 11412 performs various types of image processing on the image signal, which is RAW data sent from the camera head 11102 .

[0205] The control unit 11413 performs various controls related to imaging of the surgical site etc. by the endoscope 11100 and 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.

[0206] Further, the control unit 11413 causes the display device 11202 to display the captured image showing the surgical site, etc., based on the image signal that has been image-processed 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 techniques. For example, the control unit 11413 can recognize surgical tools such as forceps, specific living body parts, bleeding, mist when the energy treatment tool 11112 is used, etc., by detecting the shape and color of the edge of an object included in the captured image. When the control unit 11413 causes the display device 11202 to display the captured image, it may use the recognition result to superimpose various types of surgery support information on the image of the surgical site. By superimposing and presenting the surgery support information to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0207] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for communication of electrical signals, an optical fiber for optical communication, or a composite cable of these.

[0208] Here, 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.

[0209] An example of an endoscopic surgery system to which the technology according to the present disclosure can be applied has been described above. Of the configurations described above, 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.

[0210] Although the present disclosure has been described above by way of the embodiment, modifications, application examples, and application examples, the present technology is not limited to the above-described embodiment, etc., and various modifications are possible. For example, although the above-described modifications have been described as modifications of the above-described embodiment, the configurations of the modifications can be appropriately combined.

[0211] In the above embodiment, an imaging device has been described as an example, but the photodetection device 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 distance measurement information. The photodetection device (imaging device) may be applied to an image sensor, a distance measurement sensor, and the like. 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.

[0212] The photodetector according to the present disclosure may also be applied as a distance measuring sensor capable of measuring distances by 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 (imaging device) may also be applied as a sensor capable of detecting an event, for example, an event-driven sensor (also called an event vision sensor (EVS), an event driven sensor (EDS), a dynamic vision sensor (DVS), etc.).

[0213] The photodetector according to an embodiment of the present disclosure includes a first layer having a first structure arranged in a first direction, a first medium arranged around the first structure and having a refractive index different from that of the first structure, a second layer having a second structure arranged in a first direction, a second medium arranged around the second structure and having a refractive index different from that of the second structure, and stacked on the first layer, and a photoelectric conversion element that photoelectrically converts light incident through the second layer and the first layer. The second structure is made of the same material as the first structure. The second structure includes a second structure in contact with the first structure. This makes it possible to realize a photodetector capable of improving characteristics with respect to incident light.

[0214] The optical element according to an embodiment of the present disclosure includes a first layer having a first medium and a refractive index different from that of the first structures, and a second layer having a second medium and a refractive index different from that of the second structures and arranged around the first structures and arranged to be aligned in the first direction. The second structures are made of the same material as the first structures. The second structures include a second structure in contact with the first structures. This makes it possible to realize an optical element having good optical properties.

[0215] In addition, the effects described in this specification are merely examples and are not limited to the description, and other effects may be obtained. In addition, the present disclosure may have the following configurations. (1) a first layer including a plurality of first structures arranged to be aligned in a first direction and a first medium arranged around the first structures and having a refractive index different from that of the first structures; a second layer including a plurality of second structures arranged to be aligned in the first direction and a second medium arranged around the second structures and having a refractive index different from that of the second structures, the second layer being stacked on the first layer; a photoelectric conversion element that performs photoelectric conversion on light incident through the second layer and the first layer; Equipped with the second structure is made of the same material as the first structure, The plurality of second structures include the second structure in contact with the first structure. Light detection device. (2) the plurality of second structures include the second structure provided so as to be stacked with the first structure, The second medium is provided so as to be laminated with the first medium. The light detection device according to (1) above. (3) The second medium is made of the same material as the first medium. The optical detection device according to (1) or (2). (4) The first structure and some of the second structures among the plurality of second structures have shapes different from each other. The optical detection device according to any one of (1) to (3). (5) The first structure and some of the second structures among the plurality of second structures have different lengths in a stacking direction of the first layer and the second layer. The photodetector according to any one of (1) to (4). (6) A lower end portion of a part of the second structures among the plurality of second structures is located below an upper end portion of the first structure. The photodetector according to any one of (1) to (5). (7) The first structure has a recess provided on the second structure side. The photodetector according to any one of (1) to (6). (8) Some of the second structures among the plurality of second structures have a portion provided in the recess of the first structure. The light detection device according to (7) above. (9) The second structure has a recess provided on the opposite side to the first structure. The photodetector according to any one of (1) to (8). (10) Further comprising an anti-reflection film provided on the second structure, A portion of the antireflection film is provided in the recess of the second structure. The light detection device according to (9) above. (11) The second structure has a protrusion provided on a side surface of the second structure on the side of the first structure. The optical detection device according to any one of (1) to (10) above. (12) At least one of the first structure and the second structure is configured to include a void. The photodetector according to any one of (1) to (11) above. (13) The refractive index of the first structure is higher than the refractive index of the first medium, The refractive index of the second structure is higher than the refractive index of the second medium. The photodetector according to any one of (1) to (12) above. (14) The first structure and the second structure each have a size equal to or smaller than the wavelength range of visible light. The photodetector according to any one of (1) to (13) above. (15) a first layer including a plurality of first structures arranged to be aligned in a first direction and a first medium arranged around the first structures and having a refractive index different from that of the first structures; a second layer including a plurality of second structures arranged to be aligned in the first direction and a second medium arranged around the second structures and having a refractive index different from that of the second structures, the second layer being laminated on the first layer; Equipped with the second structure is made of the same material as the first structure, The plurality of second structures include the second structure in contact with the first structure. Optical elements. (16) the plurality of second structures include the second structure provided so as to be stacked with the first structure, The second medium is provided so as to be laminated with the first medium. The optical element according to (15) above. (17) The second medium is made of the same material as the first medium. The optical element according to (15) or (16) above. (18) The first structure and some of the second structures among the plurality of second structures have shapes different from each other. The optical element according to any one of (15) to (17) above. (19) The first structure and some of the second structures among the plurality of second structures have different lengths in a stacking direction of the first layer and the second layer. The optical element according to any one of (15) to (18) above. (20) An optical system; a light detection device that receives light transmitted through the optical system; Equipped with The light detection device includes: a first layer including a plurality of first structures arranged to be aligned in a first direction and a first medium arranged around the first structures and having a refractive index different from that of the first structures; a second layer including a plurality of second structures arranged to be aligned in the first direction and a second medium arranged around the second structures and having a refractive index different from that of the second structures, the second layer being stacked on the first layer; a photoelectric conversion element that performs photoelectric conversion on light incident through the second layer and the first layer; having the second structure is made of the same material as the first structure, The plurality of second structures include the second structure in contact with the first structure. electronic equipment. [Explanation of symbols]

[0216] 1...imaging device, 10...semiconductor layer, 12...photoelectric conversion section, 51...first structure, 52...second structure, 60...light guiding section, 61...first member, 62...second member, 71...first layer, 72...second layer, 80...optical layer.

Claims

1. a first layer including a plurality of first structures arranged to be aligned in a first direction and a first medium arranged around the first structures and having a refractive index different from that of the first structures; a second layer including a plurality of second structures arranged to be aligned in the first direction and a second medium arranged around the second structures and having a refractive index different from that of the second structures, the second layer being stacked on the first layer; a photoelectric conversion element that performs photoelectric conversion on light incident through the second layer and the first layer; Equipped with The second structure is made of the same material as the first structure, The plurality of second structures include the second structure in contact with the first structure. Light detection device.

2. the plurality of second structures include the second structure provided so as to be stacked with the first structure, The second medium is provided so as to be laminated with the first medium.

2. The optical detection device according to claim 1.

3. The second medium is made of the same material as the first medium.

2. The optical detection device according to claim 1.

4. The first structure and some of the second structures among the plurality of second structures have different shapes.

2. The optical detection device according to claim 1.

5. The first structure and some of the second structures among the plurality of second structures have lengths different from each other in a stacking direction of the first layer and the second layer.

2. The optical detection device according to claim 1.

6. A lower end portion of a part of the second structures among the plurality of second structures is located below an upper end portion of the first structure.

2. The optical detection device according to claim 1.

7. The first structure has a recess provided on the second structure side.

2. The optical detection device according to claim 1.

8. Some of the second structures among the plurality of second structures have a portion provided in the recess of the first structure.

8. The optical detection device according to claim 7.

9. The second structure has a recess provided on the opposite side to the first structure.

2. The optical detection device according to claim 1.

10. Further comprising an anti-reflection film provided on the second structure, A portion of the anti-reflection film is provided in the recess of the second structure.

10. The optical detection device according to claim 9.

11. The second structure has a protrusion provided on a side surface of the second structure on the side of the first structure.

2. The optical detection device according to claim 1.

12. At least one of the first structure and the second structure is configured to include a void.

2. The optical detection device according to claim 1.

13. The refractive index of the first structure is higher than the refractive index of the first medium, The refractive index of the second structure is higher than the refractive index of the second medium.

2. The optical detection device according to claim 1.

14. The first structure and the second structure each have a size equal to or smaller than the wavelength range of visible light.

2. The optical detection device according to claim 1.

15. a first layer including a plurality of first structures arranged to be aligned in a first direction and a first medium arranged around the first structures and having a refractive index different from that of the first structures; a second layer including a plurality of second structures arranged to be aligned in the first direction and a second medium arranged around the second structures and having a refractive index different from that of the second structures, the second layer being laminated on the first layer; Equipped with The second structure is made of the same material as the first structure, The plurality of second structures include the second structure in contact with the first structure. Optical elements.

16. the plurality of second structures include the second structure provided so as to be stacked with the first structure, The second medium is provided so as to be laminated with the first medium.

16. The optical element according to claim 15.

17. The second medium is made of the same material as the first medium.

16. The optical element according to claim 15.

18. The first structure and some of the second structures among the plurality of second structures have different shapes.

16. The optical element according to claim 15.

19. The first structure and some of the second structures among the plurality of second structures have lengths different from each other in a stacking direction of the first layer and the second layer.

16. The optical element according to claim 15.

20. An optical system; a light detection device that receives light transmitted through the optical system; Equipped with The light detection device includes: a first layer including a plurality of first structures arranged to be aligned in a first direction and a first medium arranged around the first structures and having a refractive index different from that of the first structures; a second layer including a plurality of second structures arranged to be aligned in the first direction and a second medium arranged around the second structures and having a refractive index different from that of the second structures, the second layer being stacked on the first layer; a photoelectric conversion element that performs photoelectric conversion on light incident through the second layer and the first layer; having The second structure is made of the same material as the first structure, The plurality of second structures include the second structure in contact with the first structure. electronic equipment.

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