Light detection devices, optical elements, and electronic devices

Abstract

To provide a photodetector capable of improving the characteristics for obliquely incident light. [Solution] An optical detection device according to one embodiment of the present disclosure comprises an optical layer having a plurality of structures including a first structure and a second structure, and a photoelectric conversion element that photoelectrically converts light incident through the optical layer. The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light.

Description

Technical Field

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

Background Art

[0002] A photodetection device that guides obliquely incident light by a two-layer spectroscopic unit having a plurality of structures has been proposed (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a photodetection device, it is desirable to be able to improve characteristics with respect to obliquely incident light.

[0005] It is desired to provide a photodetection device capable of improving characteristics with respect to obliquely incident light.

Means for Solving the Problems

[0006] A photodetection device according to an embodiment of the present disclosure includes an optical layer having a plurality of structures including a first structure and a second structure, and a photoelectric conversion element that photoelectrically converts light incident through the optical layer. The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure is different from the width of the first structure according to the incident angle of the incident light. An optical element according to an embodiment of the present disclosure includes a substrate and an optical layer having a plurality of structures including a first structure and a second structure and provided so as to be laminated on the substrate. The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure is different from the width of the first structure according to the incident angle of the incident light. An electronic device according to one embodiment of the present disclosure comprises an optical system and a photodetector that receives light transmitted through the optical system. The photodetector has an optical layer having a plurality of structures including a first structure and a second structure, and a photoelectric conversion element that converts light incident through the optical layer into photoelectric energy. The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a block diagram showing an example of the schematic configuration of an imaging device, which is an example of a photodetector according to the first embodiment of the present disclosure. [Figure 2] Figure 2 shows an example of the pixel section of an imaging device according to the first embodiment of this disclosure. [Figure 3A] Figure 3A is a diagram illustrating an example of a planar configuration of an imaging device according to the first embodiment of the present disclosure. [Figure 3B] Figure 3B is a diagram illustrating an example of a planar configuration of an imaging device according to the first embodiment of this disclosure. [Figure 4] Figure 4 is a diagram showing an example of the pixel circuit configuration of an imaging device according to the first embodiment of this disclosure. [Figure 5] Figure 5 is a diagram illustrating an example of the configuration of an imaging device according to the first embodiment of this disclosure. [Figure 6] Figure 6 is a diagram illustrating an example of the configuration of an imaging device according to the first embodiment of this disclosure. [Figure 7] Figure 7 is a diagram illustrating an example of the configuration of an imaging device according to the first embodiment of this disclosure. [Figure 8] Figure 8 is a diagram illustrating an example of the configuration of an imaging device according to the first embodiment of this disclosure. [Figure 9] Figure 9 is a diagram illustrating an example of the configuration of an imaging device according to the first embodiment of this disclosure. [Figure 10]FIG. 10 is a diagram for explaining a configuration example of an imaging device according to the first embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram for explaining a configuration example of an 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 the first embodiment of the present disclosure. [Figure 13] FIG. 13 is a diagram for explaining a configuration example of an imaging device according to the first embodiment of the present disclosure. [Figure 14] FIG. 14 is a diagram showing another configuration example of an imaging device according to the first embodiment of the present disclosure. [Figure 15] FIG. 15 is a diagram for explaining a configuration example of an imaging device according to the first embodiment of the present disclosure. [Figure 16A] FIG. 16A is a diagram for explaining a configuration example of an imaging device according to the first embodiment of the present disclosure. [Figure 16B] FIG. 16B is a diagram for explaining a configuration example of an imaging device according to the first embodiment of the present disclosure. [Figure 16C] FIG. 16C is a diagram for explaining a configuration example of an imaging device according to the first embodiment of the present disclosure. [Figure 17] FIG. 17 is a diagram for explaining a configuration example of a structure of an imaging device according to Modification 1 of the present disclosure. [Figure 18] FIG. 18 is a diagram for explaining another configuration example of a structure of an imaging device according to Modification 1 of the present disclosure. [Figure 19] FIG. 19 is a diagram for explaining another configuration example of a structure of an imaging device according to Modification 1 of the present disclosure. [Figure 20] FIG. 20 is a diagram for explaining a configuration example of an imaging device according to Modification 2 of the present disclosure. [Figure 21] FIG. 21 is a diagram for explaining a configuration example of an imaging device according to Modification 3 of the present disclosure. [Figure 22A] FIG. 22A is a diagram for explaining a configuration example of an imaging device according to Modification 4 of the present disclosure. [Figure 22B]FIG. 22B is a diagram for explaining a configuration example of an imaging device according to Modification Example 4 of the present disclosure. [Figure 23] FIG. 23 is a diagram for explaining a configuration example of an optical element according to the second embodiment of the present disclosure. [Figure 24] FIG. 24 is a diagram for explaining a configuration example of an optical element according to the second embodiment of the present disclosure. [Figure 25] FIG. 25 is a block diagram showing a configuration example of an electronic device having an imaging device. [Figure 26] FIG. 26 is a block diagram showing an example of a schematic configuration of a vehicle control system. [Figure 27] FIG. 27 is an explanatory diagram showing an example of the installation positions of an external vehicle information detection unit and an imaging unit. [Figure 28] FIG. 28 is a diagram showing an example of a schematic configuration of an endoscopic surgery system. [Figure 29] FIG. 29 is a block diagram showing an example of the functional configuration of a camera head and a CCU.

Embodiments of the Invention

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

[0009] <1. First Embodiment> FIG. 1 is a block diagram showing an example of a schematic configuration of an imaging device which is an example of a light detection device according to the first embodiment of the present disclosure. FIG. 2 is a diagram showing an example of a pixel portion of the imaging device according to the first embodiment. A light detection device is a device capable of detecting incident light. An imaging device 1 which is an example of a light detection device has a plurality of pixels P including a photoelectric conversion portion, and is configured to photoelectrically convert incident light to generate a signal.

[0010] The imaging device 1 generates a signal by receiving light transmitted through an optical system (not shown) including an optical lens and an aperture (diaphragm). The imaging device 1 is constructed using a substrate (for example, a semiconductor substrate such as a Si (silicon) substrate or an SOI (silicon on insulator) substrate) on which each pixel P is provided with a photoelectric conversion unit. The imaging device 1 may also have a structure (layered structure) composed of multiple semiconductor layers stacked on top of each other.

[0011] The photoelectric conversion unit of a pixel P is, for example, a photodiode (PD) and is configured to convert light into photoelectric energy. Each photoelectric conversion unit of a pixel P can also be called a photoelectric conversion element or a photoelectric conversion region. The imaging device 1 has a region (pixel section 100) where a plurality of pixels P are provided, as shown in the example in Figure 1 or Figure 2. The imaging device 1 has, for example, a pixel section 100 in which a plurality of pixels P are arranged in a matrix in two dimensions as an imaging area.

[0012] The imaging device 1 captures incident light (image light) from the subject to be measured through 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 photoelectric conversion of the received light (e.g., visible light, infrared light, etc.). The imaging device 1, being a light detection device, is a device capable of receiving light and generating signals, and can also be called a light receiving device.

[0013] The imaging device 1 (light detection device) is configured, for example, as an image sensor. The imaging device 1 is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, a CCD (Charge Coupled Device) image sensor, etc. The imaging device 1 can be used in various electronic devices such as digital still cameras, video cameras, and mobile phones. The light detection device and optical elements according to this disclosure can be applied to various electronic or optical devices.

[0014] As shown in Figure 2, the direction of light incidence from the subject being measured is defined as the Z-axis direction, the left-right direction perpendicular to the Z-axis direction is defined as the X-axis direction, and the up-down direction perpendicular to both the Z-axis and X-axis directions is defined as the Y-axis direction. In subsequent figures, directions may also be indicated based on the direction of the arrows in Figure 2.

[0015] [Outline configuration of the imaging device] The imaging device 1, as an example, includes a pixel section 100, a pixel control unit 111, a signal processing unit 112, a control unit 113, and a processing unit 114, as shown in Figure 1. The imaging device 1 is also provided with, for example, a plurality of control lines Lc and a plurality of signal lines Ls. The pixel section 100 is a pixel array in which a plurality of pixels P are arranged. The number and arrangement of pixels P provided in the pixel section 100 (i.e., the pixel array) can be changed as appropriate.

[0016] The control line Lc is a signal line capable of transmitting signals to control the pixel P, and is connected to the pixel control unit 111 and the pixel P of the pixel unit 100. In the example shown in Figure 1, multiple control lines Lc are wired to each pixel row of the pixel unit 100, which is composed of multiple pixels P arranged horizontally (in the row direction). The control line Lc is configured to transmit control signals for reading signals from the pixel P.

[0017] The multiple control lines Lc for each pixel row of the imaging device 1 include, for example, wiring that transmits signals to control the transfer transistor, wiring that transmits signals to control the selection transistor, and wiring that transmits signals to control the reset transistor. The control lines Lc can also be called drive lines (or pixel drive lines) that transmit signals to drive the pixels P.

[0018] The signal line Ls is a signal line capable of transmitting signals from the pixel P, and is connected to the pixel P of the pixel unit 100 and the signal processing unit 112. In the pixel unit 100, for example, one or more signal lines Ls are wired for each pixel column, which is composed of multiple pixels P arranged vertically (in the column direction). The signal line Ls is electrically connected to the pixel P and is configured to transmit signals output from the pixel P.

[0019] In the imaging device 1, multiple signal lines Ls may be provided for a single pixel row. For example, the imaging device 1 has multiple signal lines Ls for each pixel row containing multiple pixels P. The number and arrangement of control lines Lc and signal lines Ls provided in the imaging device 1 are not limited to the illustrated example and can be changed as appropriate.

[0020] The pixel control unit 111 is configured to control each pixel P of the pixel unit 100. The pixel control unit 111 is a control circuit (pixel control circuit) and is composed of multiple circuits, such as a buffer, a shift register, and an address decoder. The pixel control unit 111 generates a signal for controlling the pixels P and outputs it to each pixel P of the pixel unit 100 via a control line Lc. The pixel control unit 111 is controlled by the control unit 113 and controls the pixels P of the pixel unit 100.

[0021] The pixel control unit 111 generates signals to control the pixels P, such as signals to control the transfer transistor of the pixel P, signals to control the selection transistor, and signals to control the reset transistor, and supplies these signals to each pixel P via the control line Lc. The pixel control unit 111 can also control the reading of pixel signals from each pixel P. The pixel control unit 111 can also be described as a pixel drive unit (pixel drive circuit) configured to drive each pixel P.

[0022] The signal processing unit 112 is configured to perform signal processing on the input pixel signal. The signal processing unit 112 is a signal processing circuit and includes, for example, a load circuit, an AD (Analog Digital) conversion circuit, a horizontal selection switch, etc. The load circuit is composed of, for example, a current source capable of supplying current to the amplification transistor of the pixel P. As an example, the load circuit together with the amplification transistor of the pixel P constitutes a source follower circuit.

[0023] Furthermore, the signal processing unit 112 may have an amplification circuit configured to amplify the signal read from the pixel P via the signal line Ls. The load circuit, amplification circuit, and AD conversion circuit, etc., are provided, for example, for each of the multiple signal lines Ls. In the imaging device 1, a load circuit, amplification circuit, and AD conversion circuit, etc., may be provided for each pixel row of the pixel section 100.

[0024] The signals output from each pixel P selected and scanned by the pixel control unit 111 are input to the signal processing unit 112 via the signal line Ls. The signal processing unit 112 can perform signal processing such as AD conversion of the pixel P signals and CDS (Correlated Double Sampling). The signals of each pixel P transmitted via each signal line Ls are processed by the signal processing unit 112 and output to the processing unit 114.

[0025] The processing unit 114 is configured to acquire the signal from each pixel P and perform signal processing. The processing unit 114 is a processing circuit and consists of, for example, circuits that perform various signal processing on the input pixel signals. The processing unit 114 is configured to include, as an example, an arithmetic circuit, a memory circuit, and so on.

[0026] The processing unit 114 can, for example, perform signal processing on the pixel signal input from the signal processing unit 112 and output the processed pixel signal. The processing unit 114 can perform various signal processing such as noise reduction, interpolation, and gradation correction. The processing unit 114 may also include a processor and memory.

[0027] The control unit 113 is configured to control each part of the imaging device 1. The control unit 113 receives data such as a clock and operating mode commands from an external source, and can output data such as internal information of the imaging device 1. The control unit 113 is a control circuit and, for example, has a timing generator configured to generate various timing signals.

[0028] The control unit 113 controls the operation of the pixel control unit 111 and the signal processing unit 112, etc., based on various timing signals (pulse signals, clock signals, etc.) generated by the timing generator. The control unit 113 may include circuits such as a PLL (Phase Locked Loop) and a DAC (Digital to Analog Converter). The control unit 113 and the processing unit 114 may be configured as an integrated unit.

[0029] The pixel unit 100, pixel control unit 111, signal processing unit 112, control unit 113, processing unit 114, etc., described above may be provided on a single substrate or on multiple substrates. The imaging device 1 may have, for example, a laminated structure formed by stacking multiple substrates.

[0030] The pixel control unit 111, signal processing unit 112, control unit 113, processing unit 114, etc. of the imaging device 1 may be provided, for example, as peripheral circuits in the peripheral area of ​​the pixel unit 100. Some or all of the signal processing unit 112, control unit 113, and processing unit 114 may be configured as an integral part.

[0031] Figures 3A and 3B are diagrams illustrating an example of the planar configuration of an imaging device according to the first embodiment. Figure 3B shows an example of the planar configuration of the semiconductor layer 10 on which the photoelectric conversion unit 11 is provided. Figure 3A also shows an example of the planar configuration of the optical layer 80 provided above the semiconductor layer 10.

[0032] In the imaging device 1, for example, in the pixel section 100, a plurality of pixels P (in Figures 3A and 3B, pixels Pr, Pg, and Pb) having photoelectric conversion units 11 (i.e., photoelectric conversion regions) are provided so as to be aligned in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction). The number and arrangement of pixels P in the pixel section 100 of the imaging device 1 can be arbitrarily set.

[0033] The imaging device 1 has an optical layer 80 provided above the photoelectric conversion unit 11 of the pixel P. The optical layer 80, as will be described later, is a layer having a plurality of structures 60, and is provided so as to be stacked on the semiconductor layer 10 on which the photoelectric conversion unit 11 is provided. The optical layer 80 is an optical element (optical component) utilizing metamaterial (metasurface) technology. The imaging device 1 and the optical layer 80 are configured to have a metastructure and can be configured as a metaoptical element.

[0034] The imaging device 1 includes an optical layer 80 having a structure 60, and is configured to guide incident light towards the photoelectric conversion unit 11. The optical layer 80 is configured, for example, as a lens that focuses light. The optical layer 80 can also be called a metalens (i.e., a metamaterial lens). The pixels P of the imaging device 1 have a region (referred to as the element region 70) where the structure 60 is provided, as shown in the example in Figure 3A.

[0035] In the imaging device 1, for example, a minute structure 60 is arranged in each element region 70 of each pixel P in the pixel section 100. The element region 70 corresponds to one region when the optical layer 80 is divided into regions for each pixel P. The element region 70 has a structure 60 and a member 65 provided around the structure 60. Multiple structures 60 are formed in the element region 70, for example, as shown in the example in Figure 3A. Structures 60 may also be arranged at the boundaries of multiple adjacent element regions 70.

[0036] The structure 60 is, for example, a structure having a columnar (pillar-like) shape. The structure 60 is, as an example, a pillar (i.e., a columnar member) having a prismatic or cylindrical shape. The optical layer 80 has the structure 60 as a nanostructure and is configured to guide incident light towards the photoelectric conversion unit 11.

[0037] Member 65 is provided around the structure 60 in the optical layer 80. Member 65 is provided, for example, to fill the space between multiple adjacent structures 60, and can also be called a filler member. The structure 60 is provided within member 65, and can also be said to be arranged by replacing a part of member 65. Structure 60 is made of a dielectric material having a refractive index different from that of member 65.

[0038] In the imaging device 1, as will be described later, structures 60 of different sizes are provided according to the distance from the center of the pixel section 100 (pixel array). For example, the optical layer 80 of the imaging device 1 is configured such that the width (diameter) of some or all of the structures 60 in each pixel P (or each element region 70) differs according to the distance from the center of the pixel section 100, i.e., the image height.

[0039] The shape of each structure 60 of the optical layer 80 can be changed as appropriate. For example, the structure 60 may have a conical or frustoconical shape. In plan view, the structure 60 may have a circular, elliptical, or polygonal shape. Furthermore, the number and arrangement of the structures 60 are not limited to the illustrated example and can be changed as appropriate.

[0040] In the example shown in Figure 3A, the pixels P of the imaging device 1 have a filter 17. The filter 17 is configured to selectively transmit light in a specific wavelength range from the incident light. The filter 17 is an RGB color filter, an infrared light transmitting filter, etc. The filter 17 is provided, for example, above the photoelectric conversion unit 11 for each pixel P or for each of several pixels P (i.e., for each predetermined number of pixels P).

[0041] The pixel section 100 of the imaging device 1 includes, for example, pixels Pr (R pixels) equipped with a filter 17 that transmits red (R) light, pixels Pg (G pixels) equipped with a filter 17 that transmits green (G) light, and pixels Pb (B pixels) equipped with a filter 17 that transmits blue (B) light. In the pixel section 100, multiple pixels Pr, multiple pixels Pg, and multiple pixels Pb are arranged repeatedly.

[0042] Pixels Pr, Pg, and Pb are arranged, for example, according to a Bayer array. In the pixel section 100, 2x2 pixels, each consisting of one pixel Pr, two pixels Pg, and one pixel Pb, are repeatedly provided. The pixel section 100 has, for example, pixel rows in which pixels Pg and Pr are arranged alternately, and pixel rows in which pixels Pb and Pg are arranged alternately.

[0043] The pixels Pr, Pg, and Pb of the pixel unit 100 generate and output pixel signals for the R component, G component, and B component, respectively. The imaging device 1 can obtain RGB pixel signals. Note that the arrangement of pixels P in the imaging device 1 is not limited to the example described above and can be set arbitrarily.

[0044] For example, pixels Pr, Pg, and Pb may each be arranged in 2x2 pixel units. In the pixel section 100, for example, four adjacent pixels Pr, four adjacent pixels Pg, and four adjacent pixels Pb may be repeatedly arranged. It can also be said that pixels Pr, Pg, and Pb are each arranged periodically in a 2x2 grid.

[0045] The filter 17 provided in the pixel P of the pixel section 100 is not limited to primary color (RGB) color filters, but may also be complementary color filters such as Cy (cyan), Mg (magenta), and Ye (yellow). A filter corresponding to W (white), that is, a filter that transmits light across the entire wavelength range of incident light, may also be provided. The filter 17 may also be a filter that transmits infrared light.

[0046] Furthermore, the filter 17 may be omitted in the imaging device 1 if necessary. For example, depending on the characteristics of the optical layer 80, the filter 17 may not be provided for some or all of the pixels P in the imaging device 1. Also, for example, the filter 17 does not need to be provided for pixels that receive white (W) light and perform photoelectric conversion.

[0047] [Pixel composition] Figure 4 shows an example of the circuit configuration of a pixel in an imaging device according to the first embodiment. The pixel P includes a photoelectric conversion unit 11, a transistor TG, a floating diffusion FD, and a readout circuit 15. The photoelectric conversion unit 11 is configured to receive light and generate a signal. The photoelectric conversion unit 11 is configured to generate electric charge by photoelectric conversion.

[0048] In the example shown in Figure 4, the photoelectric conversion unit 11 is a photodiode (PD) that converts incident light into electric charge. The photoelectric conversion unit 11 can perform photoelectric conversion to generate a charge corresponding to the amount of light received. The photoelectric conversion unit 11 is a photoelectric conversion element and can also be called a light receiving element. The readout circuit 15 is configured to output a signal based on the photoelectrically converted charge.

[0049] Transistor TG is configured to transfer the charge photoelectrically converted in the photoelectric conversion unit 11 to the floating diffusion FD. Transistor TG is controlled by signal STG to electrically connect or disconnect the photoelectric conversion unit 11 and the floating diffusion FD. Transistor TG is a transfer transistor. Transistor TG can transfer the charge converted and stored in the photoelectric conversion unit 11 to the floating diffusion FD.

[0050] The floating diffusion FD is a storage unit and is configured to store the transferred charge. The floating diffusion FD can store the charge photoelectrically converted by the photoelectric conversion unit 11. The floating diffusion FD stores the transferred charge and converts it into a voltage corresponding to the capacitance of the floating diffusion FD. The floating diffusion FD can also be described as a storage unit capable of holding charge.

[0051] The readout circuit 15, as an example, includes a transistor AMP, a transistor SEL, and a transistor RST. The readout circuit 15 can read out pixel signals based on the charge photoelectrically converted in the photoelectric conversion unit 11 (i.e., the photoelectric conversion region). The readout circuit 15 may also include a floating diffusion FD. Furthermore, the readout circuit 15 may also include a transistor TG.

[0052] The transistor AMP is configured to generate and output a signal based on the charge stored in the floating diffusion FD. The transistor AMP is an amplifying transistor. The transistor AMP can generate and output a signal based on the charge converted by the photoelectric conversion unit 11.

[0053] The gate of the transistor AMP is electrically connected to the floating diffusion diode (FD), and the voltage converted by the floating diffusion diode is input to it. The drain of the transistor AMP is connected to a power line that supplies, for example, the power supply voltage (the power supply voltage VDD in the example shown in Figure 4).

[0054] The source of the transistor AMP is connected to the signal line Ls, for example, 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 it to the signal line Ls.

[0055] The transistor SEL is configured to control the output of the pixel signal. The transistor SEL is electrically connected in series with the transistor AMP, for example, as shown in Figure 4. The transistor SEL is controlled by the signal SSEL and is configured to output the signal from the transistor AMP to the signal line Ls. The transistor SEL is a selection transistor. The transistor SEL can control the timing of the pixel signal output.

[0056] The transistor SEL is configured to output a signal based on the charge converted by the photoelectric conversion unit 11. The transistor SEL can output the pixel signal of pixel P to the signal line Ls. The transistor SEL may also be electrically connected in series between the power line to which the power supply voltage (power supply voltage VDD in the example shown in Figure 4) is supplied and the transistor AMP. Furthermore, the transistor SEL may be omitted if necessary.

[0057] The transistor RST is configured to reset the voltage of the floating diffusion FD. In the example shown in Figure 4, the transistor RST is electrically connected to a power line to which the power supply voltage VDD is supplied and is configured to perform a reset of the charge of pixel P. The transistor RST is a reset transistor.

[0058] Transistor RST is controlled by signal SRST and can reset the charge accumulated in the floating diffusion FD and reset the voltage of the floating diffusion FD. Transistor RST electrically connects the power line and the floating diffusion FD and discharges the charge accumulated in the floating diffusion FD. Transistor RST can also reset the charge accumulated in the photoelectric conversion unit 11 via transistor TG.

[0059] The readout circuit 15 may be configured to allow changing the conversion gain (i.e., conversion efficiency) when converting charge to voltage. The readout circuit 15 may have, for example, a transistor (switching transistor) used to set the conversion gain. The switching transistor is electrically connected, for example, between the floating diffusion FD and the transistor RST.

[0060] In the readout circuit 15, when the switching transistor is turned on, the capacitance added to the floating diffusion FD of the pixel P increases, and the conversion gain (conversion efficiency) when converting charge to voltage is switched. The switching transistor can change the conversion gain by switching the capacitance connected to the gate of transistor AMP. The switching transistor may be electrically connected in series with transistor RST or electrically connected in parallel with transistor RST.

[0061] The aforementioned transistors TG (transfer transistor), AMP (amplifier transistor), SEL (selection transistor), RST (reset transistor), and switching transistor are, for example, MOS transistors (MOSFETs) that have gate, source, and drain terminals.

[0062] In the example shown in Figure 4, transistors TG, AMP, SEL, and RST are each composed of NMOS transistors. The transistor for pixel P may, if necessary, be composed of a PMOS transistor.

[0063] The pixel control unit 111 (see Figure 1) of the imaging device 1 supplies control signals to the gates of transistors TG, SEL, RST, switching transistors, etc. of each pixel P via the control line Lc described above, and sets the transistors to an ON state (conducting state) or an OFF state (non-conducting state).

[0064] The multiple control lines Lc for each pixel row of the imaging device 1 include, as an example, wiring that transmits the signal STG for controlling transistor TG, wiring that transmits the signal SSEL for controlling transistor SEL, wiring that transmits the signal SRST for controlling transistor RST, and wiring that transmits signals for controlling switching transistors.

[0065] The transistors TG, SEL, RST, and switching transistors are controlled on and off by the pixel control unit 111. The pixel control unit 111 controls the readout circuit 15 for each pixel P, causing each pixel P to output a pixel signal to the signal line Ls. The pixel control unit 111 can control the reading of the pixel signal from each pixel P to the signal line Ls.

[0066] The imaging device 1 may have a configuration in which multiple pixels P share one readout circuit 15. The readout circuit 15 is provided for multiple pixels P, for example. In the imaging device 1, a readout circuit 15 is provided for each of the multiple pixels P, and one readout circuit 15 may be shared by multiple pixels P. As an example, a 2x2 pixel array, composed of four adjacent pixels P, may share one readout circuit 15.

[0067] [Configuration of the imaging device] Figures 5 to 8 are diagrams illustrating an example configuration of an imaging device according to the first embodiment. Figures 5 and 6 are diagrams illustrating an example configuration in the central region of the pixel section 100 (i.e., pixel array) of the imaging device 1. Figure 5 shows an example of the cross-sectional configuration of the imaging device 1, and Figure 6 shows an example of the planar configuration of the imaging device 1.

[0068] Furthermore, Figures 7 and 8 show examples of configurations in regions where the distance from the center of the pixel section 100 (pixel array), i.e., the image height, is higher than in the cases of Figures 5 and 6. Figure 7 shows an example of a cross-sectional configuration of the imaging device 1, and Figure 8 shows an example of a planar configuration of the imaging device 1.

[0069] In the central part of the pixel section 100 of the imaging device 1, light from the optical system (optical lens, etc.) is incident almost perpendicularly, as shown by the white arrow in Figure 5. In the peripheral part located outside the central part, that is, the region away from the center of the pixel section 100, light is incident at an oblique angle, as shown by the white arrow in Figure 7.

[0070] The imaging device 1 includes, for example, an optical layer 80, a spacer layer 30, a filter 17, a semiconductor layer 10, and a wiring layer 90, as shown in the examples in Figures 5 and 7. The imaging device 1 has a configuration in which the optical layer 80, the spacer layer 30, the filter 17, the semiconductor layer 10, and the wiring layer 90 are stacked in the Z-axis direction. From the side where light is incident, the optical layer 80, the spacer layer 30, the layer on which the filter 17 is provided, the semiconductor layer 10, and the wiring layer 90 are provided.

[0071] The semiconductor layer 10 is composed of a semiconductor substrate such as a Si substrate or an SOI substrate. The semiconductor layer 10 may also be a SiGe (silicon germanium) substrate, a SiC (silicon carbide) substrate, or other materials. The semiconductor layer 10 may also be composed of a III-V compound semiconductor material.

[0072] As shown in Figure 5, the semiconductor layer 10 has opposing surfaces 11S1 and 11S2. Surface 11S2 is the surface opposite to surface 11S1. Surface 11S1 of the semiconductor layer 10 is, for example, the light-receiving surface (light incident surface). Surface 11S2 of the semiconductor layer 10 is the element-forming surface on which elements such as transistors and capacitive elements are formed. A gate electrode, a gate insulating film (for example, a gate oxide film), etc., are provided on surface 11S2 of the semiconductor layer 10.

[0073] In the example shown in Figure 5, for example, a filter 17 and a spacer layer 30 are provided on the surface 11S1 side of the semiconductor layer 10. A wiring layer 90 is provided on the surface 11S2 side of the semiconductor layer 10. The optical layer 80, the spacer layer 30, and the filter 17 are stacked on the semiconductor layer 10 in the thickness direction perpendicular to the surface 11S1 of the semiconductor layer 10. The optical layer 80 is provided on the side into which light from the optical system is incident, and the wiring layer 90 is provided on the side opposite to the side into which light is incident.

[0074] In the semiconductor layer 10, a plurality of photoelectric conversion units 11 are provided along the surfaces 11S1 and 11S2 of the semiconductor layer 10. The photoelectric conversion unit 11 is a photoelectric conversion element and can also be called a photoelectric conversion region (or photoelectric conversion layer). For example, a plurality of photoelectric conversion units 11 are embedded in the semiconductor layer 10. The photoelectric conversion unit 11 is provided between the surfaces 11S1 and 11S2 of the semiconductor layer 10.

[0075] The optical layer 80 includes an element region 70 having a structure 60 and is configured to guide incident light toward the photoelectric conversion unit 11. The optical layer 80 has, for example, a plurality of structures 60 arranged in the X-axis direction (or Y-axis direction). The optical layer 80 including the structures 60 is provided, for example, above the filter 17. As an example, the optical layer 80 is provided stacked on the filter 17 via a spacer layer 30.

[0076] The optical layer 80 includes a structure 60 as a nanostructure and a member 65 provided around the structure 60. The structure 60 and the member 65 are made of materials having different refractive indices. The structure 60 is formed, for example, as a nanopillar and can also be called a metasurface element. The optical layer 80 can also be called a metasurface layer or a metamaterial layer.

[0077] The optical layer 80 has, for example, an element region 70 including a plurality of structures 60 and members 65 for each pixel P or a plurality of pixels P in the pixel section 100, as shown in the examples in Figures 5 and 7. The photoelectric conversion unit 11 converts the light incident on it via the optical layer 80, the spacer layer 30, and the filter 17 into photoelectric power.

[0078] The wiring layer 90 is provided laminated on the semiconductor layer 10. The wiring layer 90 includes, for example, a conductive film and an insulating film, and has a plurality of wirings and a plurality of vias. The wiring layer 90 has a configuration in which a plurality of wirings are laminated with an insulating film acting as an interlayer insulating film (interlayer insulating layer). The wiring layer 90 is configured as, for example, a multilayer wiring layer and may include two or more or three or more layers of wiring.

[0079] The wiring of the wiring layer 90 is formed using metallic materials such as aluminum (Al), copper (Cu), and tungsten (W). The wiring of the wiring layer 90 may also be made of polysilicon (Poly-Si) or other conductive materials. The interlayer insulating film may be formed using silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), or other insulating materials.

[0080] For example, the readout circuit 15 (see Figure 4) described above is provided in the semiconductor layer 10 and the wiring layer 90 for each pixel P or for each of a plurality of pixels P (i.e., for each predetermined number of pixels P). In addition, the pixel control unit 111, signal processing unit 112, control unit 113, processing unit 114 (see Figure 1), etc., described above may be provided in the semiconductor layer 10 and the wiring layer 90, or they may be provided on a substrate separate from the semiconductor layer 10.

[0081] The spacer layer 30 is provided between the semiconductor layer 10 and the optical layer 80. In the example shown in Figure 5, the spacer layer 30 is formed to be laminated on the layer in which the filter 17 is provided. The spacer layer 30 is composed of an insulating film such as an oxide film, a nitride film, or an oxynitride film, and can also be called an insulating layer. The spacer layer 30 may be composed of an insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or aluminum oxide (AlO), or it may be composed of other materials.

[0082] The spacer layer 30 (i.e., the insulating layer) may be made of a low refractive index material such as silicon oxide, for example. The spacer layer 30 may also be made of another material that transmits light in the wavelength range to be measured. The spacer layer 30 can also be called a transparent layer that transmits light. The optical layer 80 may include at least a part of the spacer layer 30.

[0083] The imaging device 1 has a filter 17, as shown in the example in Figure 5 or Figure 7. The filter 17 is provided above the photoelectric conversion unit 11, for example, for each pixel P or for each of several pixels P (i.e., for each predetermined number of pixels P). As an example, the filter 17 is provided between the semiconductor layer 10 and the spacer layer 30, and is located between the semiconductor layer 10 and the optical layer 80. The filter 17 is an RGB color filter, a CMY color filter, etc.

[0084] In the imaging device 1, the filter 17 reduces color mixing between pixels P. This suppresses noise from being mixed into the pixel signal, thereby preventing a decrease in image quality of the image generated using the pixel signal. The filter 17 may also be provided within the spacer layer 30. For example, the filter 17 is provided in the spacer layer 30 between the semiconductor layer 10 and the optical layer 80.

[0085] The imaging device 1 has a separation region 40, as shown in the example in Figure 5. The separation region 40 is a separation region (separation section) provided around a pixel P (or photoelectric conversion unit 11). The separation region 40 is constructed, for example, using a trench (groove). The separation region 40 is provided in the semiconductor layer 10 between a plurality of adjacent pixels P, separating the pixels P (or photoelectric conversion unit 11).

[0086] The isolation region 40 may be provided, for example, so as to surround the photoelectric conversion unit 11 on all four sides in a plan view (i.e., when viewed in the XY plane) (see also Figure 3B). As an example, the isolation region 40 is formed in a grid pattern in the semiconductor layer 10 so as to surround each photoelectric conversion unit 11 of each pixel P. At least a part of the isolation region 40 is provided at the boundary between adjacent pixels P. The isolation region 40 can also be called an inter-pixel isolation region or inter-pixel isolation wall. The isolation region 40 may be provided so as to penetrate the semiconductor layer 10.

[0087] The isolation region 40, for example, has an FTI (Full Trench Isolation) structure and is formed to extend to the surface 11S2 of the semiconductor layer 10. Alternatively, the isolation region 40 may extend from the surface 11S1 of the semiconductor layer 10 to the space between surfaces 11S1 and 11S2. An insulating film, such as a silicon oxide film, silicon nitride film, silicon oxynitride film, or aluminum oxide film, is provided within the trench of the isolation region 40.

[0088] The trenches of the isolation region 40 may be filled with polysilicon, metallic materials, other insulating materials, etc. The isolation region 40 may be formed using other insulating materials having a low refractive index. Voids (caves) may be provided within the isolation region 40. The isolation region 40 may be composed of semiconductor regions (p-type or n-type semiconductor regions) formed by ion implantation.

[0089] In the imaging device 1, the provision of a separation region 40 suppresses the leakage of charge converted by the photoelectric conversion unit 11 of pixel P to surrounding pixels P (or photoelectric conversion unit 11). Furthermore, it suppresses the leakage of unwanted light to surrounding pixels P, thereby suppressing, for example, crosstalk between pixels. It also makes it possible to suppress the inclusion of noise in the pixel signal.

[0090] The imaging device 1 may have at least one of a fixed charge film and a reflection suppression film on the surface 11S1 side of the semiconductor layer 10. The fixed charge film and the reflection suppression film are provided, for example, between the semiconductor layer 10 and the filter 17. The fixed charge film and the reflection suppression film are composed of a metal compound (metal oxide, metal nitride, etc.) as an example, and can also be called a metal compound layer. The fixed charge film is a film having a fixed charge and is formed, for example, using a high dielectric material.

[0091] The fixed charge film may be composed of a metal oxide such as aluminum oxide or hafnium oxide. The fixed charge film is, for example, a film having a negative fixed charge. At least a portion of one of the fixed charge film and the reflection suppression film may be provided in the semiconductor layer 10 so as to be along the side wall (side surface) of the isolation region 40.

[0092] In the imaging device 1, the presence of a fixed charge film can suppress the generation of dark current at the interface of the semiconductor layer 10. The fixed charge film may be composed of other metal oxide films, or it may be composed of a metal nitride film or a metal oxynitride film. In the imaging device 1, the fixed charge film may be a film having a positive fixed charge.

[0093] The reflection suppression film is composed of a metal oxide such as hafnium oxide or tantalum oxide. The reflection suppression film (i.e., anti-reflective film) is provided on the surface 11S1 side of the semiconductor layer 10 to reduce (suppress) reflection. As an example, the reflection suppression film is provided stacked with a fixed charge film. The reflection suppression film may be composed of an insulating material such as silicon nitride, silicon oxide, or aluminum oxide, or it may be composed of other materials.

[0094] Light transmitted through an optical system (such as an imaging lens and aperture) is incident on the optical layer 80. Light from the object being measured is incident on the structure 60 of the optical layer 80 via the optical system. The optical layer 80 has a nanostructure structure 60 and is configured to guide the light incident from above toward the photoelectric conversion unit 11.

[0095] Multiple structures 60 of the optical layer 80 are arranged two-dimensionally in the X-axis and Y-axis directions. For example, the multiple structures 60 of each element region 70 are arranged so as to be aligned with each other in the X-axis or Y-axis direction, with a portion of the member 65 in between. The structures 60 have, for example, a prismatic or cylindrical shape. In plan view (i.e., viewed in the XY plane), the structures 60 may be quadrilateral, circular, elliptical, or have other shapes.

[0096] The structure 60 is also referred to as, for example, a nanopillar, metaatom, nanopost, metasurface structure, or microstructure. The optical layer 80 is configured as an optical component (optical element) that guides light. The optical layer 80 utilizes the nanostructure structure 60 to propagate light to the photoelectric conversion unit 11. The optical layer 80 is configured, for example, to guide light by giving a phase delay to the light incident through the optical system.

[0097] In the optical layer 80, structures 60 are provided in each element region 70 to give a desired phase profile to the incident light. For example, the material of the structures 60 (optical constants of the structures 60), the size of the structures 60 (width (diameter), height, etc.), the number of structures, the spacing between them (pitch), etc. are determined so that light in the wavelength range to be detected is focused onto a predetermined photoelectric conversion unit 11.

[0098] The structure 60, in plan view (i.e., viewed in the XY plane), has a size that is, for example, less than or equal to a predetermined wavelength of incident light. The structure 60, when viewed in the XY plane, may have a size that is less than or equal to the wavelength range of the light to be measured (e.g., the wavelength range of visible light or the wavelength range of infrared light). The size of the structure 60 when viewed in the XZ or YZ plane (e.g., the height of the structure 60) may be less than or equal to the predetermined wavelength of incident light, or it may be greater than the wavelength of incident light.

[0099] Member 65 is provided between multiple adjacent structures 60. Member 65 is a member located around the structures 60 and can also be called a support member or a material layer. Member 65 may be formed to cover the multiple structures 60. For example, part of member 65 may be located on top of the structures 60. Part of member 65 may be provided below the structures 60.

[0100] In each element region 70 of the optical layer 80, for example, multiple structures 60 are arranged at intervals less than or equal to a predetermined wavelength of incident light. As an example, multiple structures 60 are provided in the X-axis and Y-axis directions at intervals less than or equal to the wavelength range of visible light. In the XY plane, multiple structures 60 may be arranged at intervals less than or equal to the wavelength range of infrared light.

[0101] The structure 60 is configured to have a refractive index different from that of the adjacent medium. The structure 60 has a refractive index different from that of the surrounding material or void, for example, member 65. The structure 60 and member 65 may be made of different materials. For example, the structure 60 may be made of a material with a relatively high refractive index.

[0102] The structure 60 is made of a material having a higher refractive index than the member 65, and thus has a higher refractive index than the member 65. The structure 60 is made of a high refractive index material and can also be called a high refractive index section. The member 65 is made of a low refractive index material and can also be called a low refractive index section. The member 65 can also be called a material layer having a different refractive index than the structure 60.

[0103] The structure 60 is composed of, for example, an oxide film containing titanium (Ti). As an example, the structure 60 is composed of titanium oxide (TiO). As another example, the structure 60 may be formed using silicon, polysilicon (Poly-Si), amorphous silicon (a-Si), germanium (Ge), etc. The structure 60 may also be formed using silicon carbide (SiC) or other silicon compounds.

[0104] The structure 60 may be composed of other metal compounds (metal oxides, metal nitrides, etc.). The structure 60 may be composed of elements, oxides, nitrides, oxynitrides, or composites thereof of titanium (Ti), hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), indium (In), niobium (Nb), etc. The structure 60 may also be composed of GaP, GaN, GaAs, etc.

[0105] The component 65 is composed of an inorganic material such as an oxide, nitride, or oxynitride. The component 65 may be composed of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), etc. The component 65 may also be formed using silicon carbide, silicon oxide carbide, silicon carbide nitride, or other silicon compounds.

[0106] The component 65 may be made of a siloxane resin, a styrene resin, an acrylic resin, or the like. The component 65 may also be made of a material in which fluorine is contained in any of these resins. The component 65 may also be formed using a material in which beads (fillers) having a higher (or lower) refractive index than the resin are embedded in any of these resins.

[0107] The materials constituting the structure 60 and the member 65 may be selected according to the refractive index difference with the surrounding material, the wavelength range of the light to be measured, etc. The structure 60 and the member 65 may each be made of inorganic materials or organic materials. The structure 60 or the member 65 may be made using voids (air). For example, the member 65 may be made including voids (cavities).

[0108] The optical layer 80 is configured to control the wavefront of light by, for example, causing a phase delay in the incident light due to the difference in refractive index between the structure 60 and the surrounding medium. The optical layer 80 adjusts the direction of propagation (i.e., direction of travel) of the light by imparting a phase delay to the incident light through the structure 60 and the member 65 surrounding the structure 60. The light, with phase imparted by the optical layer 80, reaches the photoelectric conversion unit 11 via the spacer layer 30 and the filter 17.

[0109] The optical layer 80 may be configured as a spectroscopic element (spectroscopic unit) capable of spectrally analyzing incident light. The optical layer 80 may be configured as a splitter (color splitter) and can also be called a color splitter layer or a color separation layer. The optical layer 80 can also be described as an optical element configured to redirect light. The optical layer 80 can efficiently guide light of any wavelength range to the filter 17 and the photoelectric conversion unit 11.

[0110] Light from the subject to be measured is incident on the photoelectric conversion unit 11 of each pixel P of the imaging device 1 via the optical layer 80. Each pixel P converts the incident light via the optical layer 80 and the filter 17, etc., into a photoelectric signal. The imaging device 1 can use the pixel signals obtained by each pixel P to generate, for example, image data showing the subject image, image data relating to the distance to the measurement target (object) (distance image data), etc.

[0111] The optical layer 80 of the imaging device 1 is provided with structures 60 of different widths (diameters) depending on their distance from the center of the pixel section 100 (pixel array). For example, the width of the structures 60 provided in the peripheral part of the pixel section 100 is different from the width of the structures 60 provided in the central part of the pixel section 100. For example, as shown in the examples in Figures 5 to 8, the width of the structures 60 in the region far from the center of the pixel section 100 is made smaller (narrower) than the width of the structures 60 in the central region of the pixel section 100.

[0112] Figure 9 is a diagram illustrating an example of the configuration of an imaging device according to the first embodiment. Figure 9(B) shows an example of the structure 60 in a region where the distance from the center of the pixel portion 100, i.e., the image height, is higher than in the case of Figure 9(A). Light from the optical system is incident almost perpendicularly on the central part of the pixel portion 100, for example, as shown by the arrow in Figure 9(A).

[0113] In the peripheral areas located outside the central part, that is, in the regions away from the center of the pixel area 100, light is incident at an oblique angle, as shown by the arrow in Figure 9(B). In the imaging device 1 according to this embodiment, the width (diameter) of the structure 60 in each element area 70 can be set such that the area (i.e., apparent area) of the structure 60 in each element area 70 is equal when viewed from the direction of light incidence, as shown schematically with dotted lines in Figures 9(A) and (B).

[0114] The imaging device 1 is configured such that the width of the structure 60 in the element region 70 differs depending on the distance from the center of the pixel region 100, as schematically shown in Figure 10. For example, the further away a region is from the center of the pixel region 100, the smaller the width of the structure 60 in that region becomes. The optical layer 80 may be configured such that the width of the structure 60 gradually decreases (becomes thinner) as the distance from the center of the pixel region 100 increases.

[0115] In the example shown in Figure 5, the width w of the structure 60 in the region away from the center of the pixel portion 100, i.e., the element region 70 shown in Figure 7, is smaller than the width w0 of the structure 60 in the central region of the pixel portion 100, i.e., the element region 70 shown in Figure 5. By configuring it in this way, the area of ​​the structure 60 as seen from incident light incident perpendicularly in Figure 5 and the area of ​​the structure 60 as seen from obliquely incident light in Figure 7 can be made approximately equal.

[0116] In the imaging device 1 according to this embodiment, the characteristics for obliquely incident light can be improved by adjusting (correcting) the width of the structure 60 in the element region 70 in accordance with the incident angle of light incident on the element region 70. This increases the amount of light received by the photoelectric conversion unit 11 and improves quantum efficiency. Furthermore, it becomes possible to suppress the degradation of image quality of images generated using pixel signals.

[0117] As shown in the example in Figure 9, the width w0 of the structure 60 (referred to as structure 60A) in the element region 70 located in the center of the pixel region 100 (referred to as element region 70A) and the width w of the structure 60 (referred to as structure 60B) in the element region 70 located away from element region 70A (referred to as element region 70B) are configured to be different from each other. The width w of structure 60B is set to be smaller than the width w0 of structure 60A, which is a reference value, depending on the incident angle θ of the principal ray L incident on element region 70B.

[0118] Structure 60B is configured to have a width w, for example, represented by the following equation (1). The width w of structure 60B can be expressed, for example, by the following equation (1), using the width w0 of structure 60A and cosθ as a correction value.

number

[0119] The incident angle θ of the principal ray L incident on the element region 70B is the angle that bisects the light beam incident on the element region 70B of the imaging device 1 from the optical system 200, as shown in Figure 11 or Figure 12. The optical system 200 is configured to include an aperture 210 (diaphragm), for example, as shown in Figure 11. The aperture 210 is located on the light incident side of the imaging device 1.

[0120] In the example shown in Figure 12, the optical system 200 has multiple lenses (lenses 221 and 222 in Figure 12). The optical system 200 may be configured to include, for example, a lens with negative refractive power and a lens with positive refractive power as lenses 221 or 222. Note that the arrangement of the aperture 210, lenses 221 and 222 is not limited to the illustrated example and can be changed as appropriate.

[0121] Light from the object to be measured enters the imaging device 1 via the optical system 200. The imaging device 1 receives the incident light from the subject, which is the object to be measured, via the optical system 200. The imaging device 1 can capture an image of the subject formed by the optical system 200, for example. The optical system 200 is an optical system having a plurality of lenses and an aperture, and can be called, for example, an imaging optical system.

[0122] The incident angle θ of the principal ray L incident on the element region 70B can also be said to be the incident angle of the central ray of the light beam incident on the element region 70B. The incident angle θ may be, for example, the angle between a line perpendicular to the surface of the optical layer 80 (i.e., the light-receiving surface (light incident surface) of the optical layer 80) (normal) and the central ray of the light beam incident on the element region 70B.

[0123] Structure 60B may be configured to have a width w represented by the following equation (2) using parameter α.

number

[0124] In equation (2), the parameter α satisfies equation (3). In equation (3), F is the F-number.

number

[0125] Parameter α is an adjustment parameter expressed using the angle φ shown in Figure 13. Parameter α represents the ratio of the correction value cosθ to the correction value cos(θ±φ) when adjusting within the range of θ±φ, and can also be called the correction ratio. Equation (3) above can be obtained, for example, by the following equations (4) and (5).

number

[0126] Figure 14 shows another example of the configuration of the imaging device according to the first embodiment. Figure 14(B) shows an example of the structure 60 in a region where the distance from the center of the pixel portion 100, i.e., the image height, is higher than in the case of Figure 14(A). As shown in the examples in Figures 14(A) and (B), the structure 60 may have a circular or elliptical shape in plan view.

[0127] In the example shown in Figure 14, the width w0 of the structure 60A in the element region 70A located in the center of the pixel region 100 and the width w of the structure 60B in the element region 70B located away from element region 70A may be configured to be different from each other. For example, the width w of the structure 60B is set to be smaller than the width w0 of the structure 60A as a reference value, depending on the incident angle θ of the principal ray L incident on the element region 70B.

[0128] Figures 15 and 16A to 16C are diagrams illustrating an example of the configuration of an imaging device according to the first embodiment. The imaging device 1 may be configured to correct (adjust) the width of the structure 60 in the direction from the center of the pixel section 100 (pixel array) to the structure 60 (i.e., in the azimuthal direction) according to the incident angle θ of the principal ray L described above, as shown by the arrow La in Figure 15, etc.

[0129] The optical layer 80 is configured such that, for example, as shown in the example in Figure 16A or Figure 16B, the width w of the structure 60 in the direction from the center of the pixel portion 100 to the structure 60 (i.e., the direction of arrow La) is different for each pixel P (or element region 70). Alternatively, for example, as schematically shown in Figure 16C, the width of the region 75 (for example, a rectangular region 75) that circumsects the structure 60 may be adjusted to set the width of the region 75.

[0130] In the imaging device 1 according to this embodiment, as described above, structures 60 of different sizes are provided according to the distance from the center of the pixel section 100. In the optical layer 80, for example, the width of part or all of the structures 60 in the element region 70 is set according to the angle of incidence of light incident on that element region 70. As a result, the optical layer 80 can appropriately guide light that is incident at an oblique angle. This makes it possible to suppress deterioration of optical characteristics with respect to obliquely incident light.

[0131] [Effects / Effects] The light detection device according to this embodiment includes an optical layer (optical layer 80) having a plurality of structures (structure 60) including a first structure and a second structure, and a photoelectric conversion element (photoelectric conversion unit 11) that converts light incident through the optical layer into photoelectric energy. The optical layer includes a first region having the first structure (for example, an element region 70A having structure 60A) and a second region having the second structure and located away from the first region (for example, an element region 70B having structure 60B). The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light.

[0132] In the photodetector (imaging device 1) according to this embodiment, the optical layer 80 includes an element region 70A having a structure 60A and an element region 70B having a structure 60B. The width of the structure 60B differs from the width of the structure 60A depending on the angle of incidence of the incident light. Therefore, the photodetector (imaging device 1) can appropriately guide light that is incident at an oblique angle. This makes it possible to realize a photodetector that can improve the characteristics for obliquely incident light.

[0133] Next, modified examples of the present disclosure will be described. In the following, components similar to those in the above embodiments will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0134] (Variation 1) In the embodiments described above, an example of the configuration of the imaging device was explained, but the configuration of the imaging device is not limited to the example described above. For example, the shape of the structure 60 of the imaging device 1 is not limited to the illustrated example and can be changed as appropriate. Figure 17 is a diagram illustrating an example of the configuration of the structure of the imaging device according to Modification 1 of this disclosure. For example, as shown in the example in Figure 17, the structure 60 may have a conical shape.

[0135] Figures 18 and 19 illustrate another example of the structure of the imaging device according to Modification 1. For example, the structure 60 may have the shape of a frustocone, as shown in the example in Figure 17. The structure 60 may be circular, elliptical, or polygonal in plan view. Also, for example, the structure 60 may have a hollow structure, as shown in the example in Figure 19. The structure 60 may be composed of air gaps (cavities). The structure 60 may be composed of multiple members having different refractive indices.

[0136] (Modification 2) Figure 20 is a diagram illustrating an example of the configuration of an imaging device according to Modification 2. The imaging device 1 may have multiple layers (multiple stages) of structures 60. The optical layer 80 of the imaging device 1 has multiple structures 60, for example, structures 60a and structures 60b, which are arranged to be stacked on top of each other. As an example, the element region 70 of each pixel P is provided with a first-stage structure 60a and a second-stage structure 60b.

[0137] As shown in Figure 20, the optical layer 80 has an optical layer 181 (first layer) including a structure 60a and a member 65a, and an optical layer 182 (second layer) including a structure 60b and a member 65b. The optical layer 182 is provided laminated on top of the optical layer 181. The structures 60a and 60b have, for example, a columnar shape, a conical shape, a frustum shape, etc.

[0138] Structure 60a and member 65a are constructed using materials with different refractive indices. Structure 60b and member 65b may also be constructed using materials with different refractive indices. In the optical layer 80, for example, the width of at least one of the structures 60a and 60b in the element region 70 may be set according to the angle of incidence of light incident on the element region 70. Note that the shape and number of structures 60a and 60b are not limited to the illustrated example and can be changed as appropriate.

[0139] In the imaging device 1 according to this modified example, the optical layer 80 having multiple layers of structures (for example, structures 60a and 60b) can appropriately guide light to the photoelectric conversion unit 11. Multiple stages of metasurface elements can efficiently focus light in any wavelength range to the photoelectric conversion unit 11.

[0140] (Variation 3) Figure 21 is a diagram illustrating an example of the configuration of an imaging device according to Modification 3. Figure 21 schematically shows an example of a cross-sectional configuration in a region away from the center of the pixel section 100. In the imaging device 1, the element region 70 having the structure 60 may be configured differently depending on the distance from the center of the pixel section 100, i.e., the image height. For example, in the central region of the pixel section 100, the pixels P are configured as shown in Figure 5 above.

[0141] In areas away from the center of the pixel section 100, an element region 70 having multiple structures 60 is positioned, for example, shifted towards the center of the pixel section 100 relative to the photoelectric conversion unit 11 and the filter 17, corresponding to the direction of incidence of light from the object being measured. In the example shown in Figure 21, the element region 70 is positioned shifted to the right relative to the photoelectric conversion unit 11 of the pixel P. For example, the center of the element region 70 of the pixel P is closer to the center of the pixel section 100 than the center of the photoelectric conversion unit 11 (or filter 17) of that pixel P.

[0142] In the pixel section 100 of the imaging device 1, the position of the structure 60 and the position of the element area 70 are adjusted according to the image height, allowing for appropriate pupil correction. This suppresses a decrease in the amount of light incident on the photoelectric conversion section 11 of each pixel P, thereby suppressing a decrease in sensitivity to incident light. This also makes it possible to improve the characteristics for obliquely incident light.

[0143] (Modification 4) Figures 22A and 22B are diagrams illustrating an example configuration of an imaging device according to Modification 4. The width of the structure 60 may be corrected for only some of the pixels in the pixel section 100 of the imaging device 1. For example, a structure 60 having a width adjusted according to the angle of incidence of light may be provided for only one or two types of pixels P, which are pixels Pr, pixels Pg, and pixels Pb.

[0144] In the imaging device 1, the width of the structure 60 may be made relatively smaller (narrower) only in pixels P of a specific color, for example, pixels Pb as shown in the example in Figure 22A. Alternatively, for example, as shown in the example in Figure 22B, the width of the structure 60 may be made relatively smaller in pixels Pb and Pg among pixels Pr, Pg, and Pb.

[0145] <2. Second Embodiment> Next, a second embodiment of the present disclosure will be described. The technology relating to the present disclosure is applicable to various electronic devices, optical devices, etc. The optical layer 80 constructed using the nanostructure described above is applicable to various optical elements (optical components). In the following, components similar to those in the above-described embodiment will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0146] Figures 23 and 24 are diagrams illustrating an example configuration of an optical element according to a second embodiment of the present disclosure. The optical element 300 has a substrate 120 and an optical layer 80. Figure 24 shows an example configuration in a region where the distance from the center of the substrate 120, i.e., the image height, is higher than in the case of Figure 23.

[0147] The optical layer 80 includes, for example, a structure 60 and a member 65 provided around the structure 60. The optical element 300 is an optical element (optical member) constructed using the nanostructure structure 60, and may be configured as a metalens (metamaterial lens).

[0148] The substrate 120 is a light-transmitting substrate (transparent substrate), and is made of, for example, a glass substrate. The substrate 120 (base material) may be made of a material having a refractive index lower than that of the structure 60, as an example. The substrate 120 may be made of, for example, quartz glass, borosilicate glass, or a resin substrate. The substrate 120 may be made of other materials that transmit the light to be measured.

[0149] As shown in Figure 23 or Figure 24, the substrate 120 has opposing surfaces 12S1 and 12S2. Surface 12S2 is the surface opposite to surface 12S1. The optical layer 80 is provided, for example, on the side of the substrate 120 to which light is incident. In the example shown in Figure 23, the optical layer 80, which includes a plurality of structures 60, is formed on surface 12S1 of the substrate 120.

[0150] The optical layer 80, including the structure 60, may be provided on the side of the substrate 120 opposite to the side where light is incident (i.e., the side where light is emitted). The optical layer 80 may be laminated on the substrate 120 via an insulating layer on either the light incident side or the light emission side of the substrate 120. The shape of the substrate 120 is not particularly limited and may be circular, rectangular, or other shapes. Furthermore, the shape, number, and arrangement of the structure 60 are not limited to the illustrated example and can be changed as appropriate.

[0151] The optical element 300 may be configured as a lens, for example, a lens that focuses light or a lens that diffuses light. The optical element 300 may also be configured as a splitter that spectrally analyzes incident light, a filter that transmits light in a specific wavelength range, or a deflector that changes the direction of light propagation. The optical element 300 may also be configured as part of the optical system of various devices, for example.

[0152] In the optical element 300, structures 60 of different sizes are provided according to their distance from the center of the substrate 120. For example, the optical layer 80 of the optical element 300 is configured such that the width (diameter) of some or all of the structures 60 in each element region 70 differs according to the distance from the center of the substrate 120, i.e., the image height.

[0153] The optical layer 80 includes, for example, an element region 70A located in the center of the substrate 120 and an element region 70B located away from element region 70A. The width of the structure 60B provided in element region 70B is set to be smaller than the width of the structure 60A provided in element region 70A, for example, depending on the incidence angle of the principal ray incident on element region 70B. By configuring the optical element 300 in this way, it is possible to improve the characteristics for obliquely incident light, as in the embodiment described above.

[0154] [Effects / Effects] The optical element according to this embodiment comprises a substrate (substrate 120) and an optical layer having a plurality of structures (structures 60) including a first structure and a second structure, and provided to be laminated on the substrate. The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light.

[0155] In the optical element (optical element 300) according to this embodiment, the optical layer 80 includes, for example, an element region 70A having a structure 60A and an element region 70B having a structure 60B. The width of the structure 60B differs from the width of the structure 60A depending on the angle of incidence of the incident light. This makes it possible to appropriately guide light that is incident at an oblique angle. This makes it possible to realize an optical element that can improve the characteristics for obliquely incident light.

[0156] <3. Application Examples> The above-mentioned imaging device 1 can be applied to any type of electronic device equipped with an imaging function, such as camera systems like digital still cameras and video cameras, or mobile phones with imaging capabilities. Figure 25 shows a schematic configuration of the electronic device 1000.

[0157] 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, all of which are interconnected via a bus line 1008.

[0158] The lens group 1001 captures incident light (image light) from the 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 it as a pixel signal to the DSP circuit 1002.

[0159] The DSP circuit 1002 is a signal processing circuit that processes signals supplied from the imaging device 1. The DSP circuit 1002 outputs image data obtained by processing the signals from the imaging device 1. The frame memory 1003 temporarily holds the image data processed by the DSP circuit 1002 on a frame-by-frame basis.

[0160] The display unit 1004 consists of a panel-type display device such as a liquid crystal panel or an organic EL (Electro Luminescence) panel, and records the video or still image data captured by the imaging device 1 onto a recording medium such as a semiconductor memory or a hard disk.

[0161] The operation unit 1006 outputs operation signals for various functions possessed by the electronic device 1000 in accordance with user operations. The power supply unit 1007 appropriately supplies various power sources to the DSP circuit 1002, frame memory 1003, display unit 1004, recording unit 1005, and operation unit 1006.

[0162] <4. Application Examples> (Examples of applications to mobile devices) The technology disclosed herein (the Technology) can be applied to a variety of products. For example, the Technology disclosed herein may be implemented as a device mounted on any type of mobile vehicle, such as an automobile, electric vehicle, hybrid electric vehicle, motorcycle, bicycle, personal mobility device, airplane, drone, ship, or robot.

[0163] Figure 26 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0164] The vehicle control system 12000 comprises multiple electronic control units connected via a communication network 12001. In the example shown in Figure 26, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0165] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0166] 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 system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0167] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0168] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0169] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that images the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0170] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking system based on information from inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0171] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0172] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0173] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 26, the output devices are exemplified as an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0174] Figure 27 shows an example of the installation position of the imaging unit 12031.

[0175] In Figure 27, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0176] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0177] Figure 27 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0178] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0179] For example, the microcomputer 12051, based on distance information obtained from imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to vehicle 12100). In particular, it can extract the nearest object on the vehicle 12100's path that is traveling in approximately the same direction as vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0180] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, heavy vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0181] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a 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 indicating a pedestrian at a desired position.

[0182] The above describes an example of a mobile control system to which the technology described herein can be applied. The technology described herein can be applied to, for example, the imaging unit 12031 of the configuration described above. Specifically, for example, the imaging device 1 and the optical element 300 can be applied to the imaging unit 12031. By applying the technology described herein to the imaging unit 12031, it becomes possible to obtain high-definition captured images. This makes it possible to perform high-precision control using captured images in the mobile control system.

[0183] (Examples of application to endoscopic surgical systems) The technology disclosed herein (the Technology) can be applied to a variety of products. For example, the Technology disclosed herein may be applied to an endoscopic surgical system.

[0184] Figure 28 shows an example of a schematic configuration of an endoscopic surgical system to which the technology described herein (the technology) may be applied.

[0185] Figure 28 illustrates a surgeon (physician) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgical system 11000. As shown in the figure, the endoscopic surgical system 11000 consists of an endoscope 11100, other surgical instruments 11110 such as an insufflation tube 11111 and an energy treatment device 11112, a support arm device 11120 for supporting the endoscope 11100, and a cart 11200 equipped with various devices for endoscopic surgery.

[0186] The endoscope 11100 consists of a barrel 11101, the tip of which is inserted into the body cavity of the patient 11132 for a predetermined length, and a camera head 11102 connected to the base end of the barrel 11101. In the illustrated example, the endoscope 11100 is shown as a so-called rigid endoscope having a rigid barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible endoscope having a flexible barrel.

[0187] An opening into which an objective lens is fitted is provided at the tip of the endoscope tube 11101. A light source device 11203 is connected to the endoscope 11100, and the light generated by the light source device 11203 is guided to the tip of the endoscope tube by a light guide extending inside the endoscope tube 11101, and is irradiated through the objective lens towards the object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a straight-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0188] The camera head 11102 contains an optical system and an image sensor. Reflected light from the object being observed (observation light) is focused onto the image sensor by the optical system. The image sensor converts the observation light into electrical signals, generating an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. This image signal is transmitted as RAW data to the camera control unit (CCU) 11201.

[0189] The CCU11201 consists of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and other components, and comprehensively controls the operation of the endoscope 11100 and the display device 11202. Furthermore, the CCU11201 receives image signals from the camera head 11102 and performs various image processing operations on these image signals, such as development processing (demosaic processing), to display the image based on those image signals.

[0190] The display device 11202 displays an image based on an image signal that has been processed by the CCU 11201, under control from the CCU 11201.

[0191] The light source device 11203 consists of a light source such as an LED (Light Emitting Diode) and supplies illumination light to the endoscope 11100 when photographing the surgical area, etc.

[0192] The input device 11204 is an input interface for the endoscopic surgical system 11000. The user can input various information and instructions to the endoscopic surgical system 11000 via the input device 11204. For example, the user can input instructions to change the imaging conditions (type of light, magnification, focal length, etc.) of the endoscope 11100.

[0193] The treatment instrument control device 11205 controls the drive of the energy treatment instrument 11112 for purposes such as tissue cauterization, incision, or vascular sealing. The insufflation device 11206 delivers gas into the patient's body cavity via the insufflation tube 11111 to inflate the body cavity of the patient 11132 for the purpose of securing a field of view by the endoscope 11100 and securing the operator's working space. 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, images, or graphs.

[0194] The light source device 11203, which supplies illumination light to the endoscope 11100 when photographing the surgical area, can be configured as a white light source consisting of, for example, an LED, a laser light source, or a combination thereof. When the white light source is configured as 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 the white balance of the captured image can be adjusted in the light source device 11203. In this case, it is also possible to time-divisionally capture images corresponding to each of the RGB light sources by irradiating the observation target with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter on the image sensor.

[0195] Furthermore, the light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. By controlling the drive of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity, images can be acquired in time-division order, and these images can be combined to generate high dynamic range images without so-called black crushing and white clipping.

[0196] Furthermore, the light source device 11203 may be configured to supply light in a predetermined wavelength band corresponding to special light observation. In special light observation, for example, by utilizing the wavelength dependence of light absorption in body tissue and irradiating with narrow-band light compared to the irradiation light used during normal observation (i.e., white light), so-called narrow-band imaging is performed to image predetermined tissues such as blood vessels on the surface of mucosa with high contrast. Alternatively, in special light observation, fluorescence observation may be performed to obtain an image from fluorescence generated by irradiation with excitation light. In fluorescence observation, excitation light is irradiated onto body tissue and fluorescence from the body tissue is observed (autofluorescence observation), or a reagent such as indocyanine green (ICG) is injected into body tissue and excitation light corresponding to the fluorescence wavelength of the reagent is irradiated onto the body tissue to obtain a fluorescence image. The light source device 11203 may be configured to supply narrow-band light and / or excitation light corresponding to such special light observation.

[0197] Figure 29 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU 11201 shown in Figure 28.

[0198] The camera head 11102 includes 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 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with one another.

[0199] The lens unit 11401 is an optical system provided at the connection point 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 then incident on the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses, including a zoom lens and a focus lens.

[0200] The imaging unit 11402 is composed of image sensors. The imaging unit 11402 may consist of one image sensor (a so-called single-chip type) or multiple image sensors (a so-called multi-chip type). If the imaging unit 11402 is composed of multiple chips, for example, each image sensor may generate an image signal corresponding to RGB, and these signals may be combined to obtain a color image. Alternatively, the imaging unit 11402 may be configured to have a pair of image sensors for acquiring image signals for the right eye and the left eye, respectively, 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 area. In addition, if the imaging unit 11402 is composed of multiple chips, multiple lens units 11401 may be provided corresponding to each image sensor.

[0201] Furthermore, the imaging unit 11402 does not necessarily have to be located in the camera head 11102. For example, the imaging unit 11402 may be located inside the lens barrel 11101, directly behind the objective lens.

[0202] The drive unit 11403 is composed of actuators and, under control from the camera head control unit 11405, moves the zoom lens and focus lens of the lens unit 11401 along the optical axis by a predetermined distance. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted as appropriate.

[0203] The communication unit 11404 consists of communication devices for sending and receiving various types of information with the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 as RAW data to the CCU 11201 via the transmission cable 11400.

[0204] Furthermore, the communication unit 11404 receives control signals from the CCU 11201 to control the drive of the camera head 11102 and supplies them to the camera head control unit 11405. These control signals include information regarding imaging conditions, such as information to specify the frame rate of the captured image, information to specify the exposure value at the time of imaging, and / or information to specify the magnification and focus of the captured image.

[0205] The imaging conditions such as frame rate, exposure value, magnification, and focus may be specified by the user as appropriate, or they may be automatically set by the control unit 11413 of the CCU11201 based on the acquired image signal. In the latter case, the endoscope 11100 will be equipped with so-called AE (Auto Exposure), AF (Auto Focus), and AWB (Auto White Balance) functions.

[0206] The camera head control unit 11405 controls the drive of the camera head 11102 based on the control signal received from the CCU 11201 via the communication unit 11404.

[0207] The communication unit 11411 consists of a communication device for sending and receiving various types of information with the camera head 11102. The communication unit 11411 receives image signals transmitted from the camera head 11102 via the transmission cable 11400.

[0208] Furthermore, the communication unit 11411 transmits control signals to the camera head 11102 to control the driving of the camera head 11102. Image signals and control signals can be transmitted by telecommunications, optical communications, etc.

[0209] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102.

[0210] The control unit 11413 performs various controls related to imaging the surgical area, etc., by the endoscope 11100, and the display of the images obtained from imaging the surgical area, etc. For example, the control unit 11413 generates control signals to control the driving of the camera head 11102.

[0211] Furthermore, the control unit 11413 displays the captured image showing the surgical area on the display device 11202 based on the image signal 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 technologies. For example, the control unit 11413 can recognize surgical instruments such as forceps, specific biological sites, bleeding, mist when using the energy treatment device 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When the control unit 11413 displays the captured image on the display device 11202, it may use the recognition results to superimpose various surgical support information onto the image of the surgical area. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced, and the surgeon 11131 can proceed with the surgery with confidence.

[0212] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable compatible with electrical signal communication, an optical fiber compatible with optical communication, or a composite cable thereof.

[0213] In the illustrated example, communication was performed via a wired connection using the transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may be performed wirelessly.

[0214] The above describes an example of an endoscopic surgical system to which the technology described herein can be applied. The technology described herein can be suitably applied to, for example, the imaging unit 11402 provided on the camera head 11102 of the endoscope 11100. By applying the technology described herein to the imaging unit 11402, it becomes possible to provide a high-definition endoscope 11100.

[0215] Although the present disclosure has been described above with reference to embodiments, modifications, application examples, and application examples, the present technology is not limited to the above embodiments, and various modifications are possible. For example, although the above modifications were described as modifications of the above embodiments, the configurations of each modification can be combined as appropriate.

[0216] In the embodiments described above, an imaging device was used as an example; however, the light detection device of this disclosure can be any device that receives incident light and converts the light into an electric charge. The output signal may be an image information signal or a distance measurement information signal. The light detection device (imaging device) can be applied to an image sensor, a distance measurement sensor, etc. Furthermore, this disclosure is not limited to back-illuminated image sensors, but is also applicable to front-illuminated image sensors.

[0217] The light detection device according to this disclosure can also be used as a distance measuring sensor capable of measuring distance using the TOF (Time Of Flight) method. The light-receiving element (photoelectric conversion unit) of each pixel may be an APD (Avalanche Photo Diode). The light-receiving element may be composed of, for example, a SPAD (Single Photon Avalanche Diode). The light detection device (imaging device) can also be used as a sensor capable of detecting events, for example, an event-driven sensor (also called an EVS (Event Vision Sensor), EDS (Event Driven Sensor), DVS (Dynamic Vision Sensor), etc.).

[0218] An optical detection device according to one embodiment of the present disclosure comprises an optical layer having a plurality of structures, including a first structure and a second structure, and a photoelectric conversion element that converts light incident through the optical layer into photoelectric energy. The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light. This makes it possible to realize an optical detection device that can improve the characteristics for obliquely incident light.

[0219] An optical element according to one embodiment of the present disclosure comprises a substrate and an optical layer having a plurality of structures, including a first structure and a second structure, and provided to be laminated on the substrate. The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light. This makes it possible to realize an optical element that can improve the characteristics for obliquely incident light.

[0220] Furthermore, the effects described herein are merely illustrative and not limited to those described; other effects may also exist. Additionally, this disclosure may take the following configuration. (1) An optical layer having multiple structures including a first structure and a second structure, A photoelectric conversion element that converts light incident through the optical layer into photoelectric energy. Equipped with, The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light. Light detection device. (2) The optical layer and the photoelectric conversion element are further provided with a color filter. The light detection device described in (1) above. (3) The pixel array includes a plurality of pixels, each having the aforementioned photoelectric conversion element, The optical layer includes a first region located in the center of the pixel array and a second region located away from the first region. The width of the second structure is smaller than the width of the first structure, depending on the angle of incidence of the principal ray incident on the second region. The light detection device described in (1) or (2) above. (4) The second structure has a width corresponding to the width of the first structure and the incident angle of the principal ray incident on the second region. The light detection device described in (3) above. (5) When the width of the first structure is w0, the width of the second structure is w, and the incident angle of the principal ray incident on the second region is θ, the width w of the second structure is expressed by the following equation (1).

number

number

number

[0221] 1...Imaging device, 10...Semiconductor layer, 11...Photoelectric conversion unit, 17...Filter, 60...Structure, 65...Component, 70...Element region, 80...Optical layer.

Claims

1. An optical layer having a plurality of structures including a first structure and a second structure, A photoelectric conversion element that converts light incident through the optical layer into photoelectric energy. Equipped with, The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light. Light detection device.

2. The optical layer and the photoelectric conversion element are further provided with a color filter. The light detection device according to claim 1.

3. The pixel array includes a plurality of pixels, each having the aforementioned photoelectric conversion element, The optical layer includes a first region located in the center of the pixel array and a second region located away from the first region. The width of the second structure is smaller than the width of the first structure, depending on the angle of incidence of the principal ray incident on the second region. The light detection device according to claim 1.

4. The second structure has a width corresponding to the width of the first structure and the incident angle of the principal ray incident on the second region. The light detection device according to claim 3.

5. The width of the first structure is w ０ When the width of the second structure is w and the incidence angle of the principal ray incident on the second region is θ, the width w of the second structure is expressed by the following equation (1). [Math 1] The light detection device according to claim 3.

6. The width of the first structure is w ０ When the width of the second structure is w and the incidence angle of the principal ray incident on the second region is θ, the width w of the second structure is expressed by the following equation (2): [Math 2] In equation (2), α satisfies equation (3) [Math 3] (In equation (3), F is the F number.) The light detection device according to claim 3.

7. The angle of incidence of the principal ray incident on the second region is the angle that bisects the luminous beam incident on the second region. The light detection device according to claim 3.

8. The incident angle of the principal ray incident on the second region is greater than the incident angle of the principal ray incident on the first region. The width of the second structure is smaller than the width of the first structure, depending on the angle of incidence of the principal ray incident on the second region. The light detection device according to claim 1.

9. The pixel array includes a plurality of pixels, each having the aforementioned photoelectric conversion element, The optical layer includes a first region located in the center of the pixel array and a second region located away from the first region. The width of the second structure in the direction from the center of the pixel array toward the second structure is smaller than the width of the first structure. The light detection device according to claim 1.

10. The width of the second structure in the direction from the center of the pixel array toward the second structure is smaller than the width of the first structure, depending on the incidence angle of the principal rays incident on the second region. The light detection device according to claim 9.

11. The second region has a plurality of the second structures, The width of some of the aforementioned second structures differs from the width of the first structure depending on the angle of incidence of the incident light. The light detection device according to claim 1.

12. The optical layer includes a first region having the first structure provided on each of the multiple stacked layers, and a second region having the second structure provided on each of the multiple layers. The light detection device according to claim 1.

13. The width of the second structure in some of the layers among the plurality of layers differs from the width of the first structure depending on the angle of incidence of the incident light. The light detection device according to claim 12.

14. The pixel array includes a plurality of pixels, each having the aforementioned photoelectric conversion element, The distance between the center of the photoelectric conversion element and the center of the second region differs depending on the distance from the center of the pixel array. The light detection device according to claim 1.

15. The first structure and the second structure each have a columnar, conical, or frustoconical shape. The light detection device according to claim 1.

16. The optical layer has members provided around the first structure and the second structure, The first structure and the second structure each have a refractive index different from that of the member. The light detection device according to claim 1.

17. circuit board and An optical layer having a plurality of structures including a first structure and a second structure, and provided to be laminated on the substrate Equipped with, The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light. Optical element.

18. The optical layer includes a first region located in the center of the substrate and a second region located away from the first region. The width of the second structure is smaller than the width of the first structure, depending on the angle of incidence of the principal ray incident on the second region. The optical element according to claim 17.

19. The second structure has a width corresponding to the width of the first structure and the incident angle of the principal ray incident on the second region. The optical element according to claim 18.

20. Optical system and A light detection device that receives light transmitted through the optical system and Equipped with, The aforementioned light detection device is An optical layer having a plurality of structures including a first structure and a second structure, A photoelectric conversion element that converts light incident through the optical layer into photoelectric energy. It has, The optical layer includes a first region having the first structure and a second region having the second structure and located away from the first region. The width of the second structure differs from the width of the first structure depending on the angle of incidence of the incident light. electronic equipment.

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