Photodetector and photodetector system

Abstract

To provide an optical detection device capable of suitable communication. [Solution] An embodiment of the photodetector of the present disclosure comprises a first substrate having a photoelectric conversion element that converts light into photoelectric energy, a second substrate laminated with the first substrate having at least a portion of a processing circuit capable of performing signal processing on a first signal generated based on the charge converted by the photoelectric conversion element, and an optical circuit capable of outputting a first optical signal based on the first signal.

Description

Technical Field

[0001] The present disclosure relates to a photodetection device and a photodetection system.

Background Art

[0002] An imaging device has been proposed that includes an imaging unit that performs photoelectric conversion of light received through a lens, and a transmission unit that transmits data of each pixel supplied from the imaging unit to a DSP (Digital Signal Processor) via a transmission path (lane) (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is desirable that the photodetection device be capable of appropriate communication.

[0005] It is desired to provide a photodetection device that enables suitable communication.

Means for Solving the Problems

[0006] A photodetection device according to an embodiment of the present disclosure includes a first substrate having a photoelectric conversion element that photoelectrically converts light, a second substrate laminated with the first substrate and having at least a part of a processing circuit capable of executing signal processing of a first signal generated based on charges converted by the photoelectric conversion element, and an optical circuit capable of outputting a first optical signal based on the first signal. One embodiment of the photodetection system of the present disclosure comprises a photodetection device and an external device. The photodetection device comprises a first substrate having a photoelectric conversion element that converts light into photoelectric energy, a second substrate laminated with the first substrate and having at least a portion of a processing circuit capable of performing signal processing on a first signal generated based on the charge converted by the photoelectric conversion element, and an optical circuit capable of transmitting a first optical signal based on the first signal to the external device. [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 an embodiment of the present disclosure. [Figure 2] Figure 2 shows an example of the pixel section of an imaging device according to an embodiment of the present disclosure. [Figure 3] Figure 3 is a diagram showing an example of the pixel circuit configuration of an imaging device according to an embodiment of the present disclosure. [Figure 4] Figure 4 shows another example of the pixel circuit configuration of an imaging device according to an embodiment of the present disclosure. [Figure 5] Figure 5 shows an example of a cross-sectional configuration of an imaging device according to an embodiment of the present disclosure. [Figure 6] Figure 6 shows an example of a cross-sectional configuration of an imaging device according to an embodiment of the present disclosure. [Figure 7] Figure 7 shows an example of a cross-sectional configuration of an imaging device according to an embodiment of the present disclosure. [Figure 8] Figure 8 is a diagram illustrating an example layout of an imaging device according to an embodiment of the present disclosure. [Figure 9] Figure 9 is a diagram illustrating an example of the configuration of the optical circuit of an imaging device according to an embodiment of the present disclosure. [Figure 10] Figure 10 is a diagram illustrating another example of the configuration of the optical circuit of the imaging device according to the embodiment of the present disclosure. [Figure 11] Figure 11 is a diagram illustrating an example of the configuration of the optical circuit of an imaging device according to an embodiment of the present disclosure. [Figure 12]FIG. 12 is a diagram for explaining a configuration example of an optical circuit of an imaging device according to an embodiment of the present disclosure. [Figure 13] FIG. 13 is a diagram for explaining another layout example of an imaging device according to an embodiment of the present disclosure. [Figure 14] FIG. 14 is a diagram for explaining a configuration example of an optical detection system according to an embodiment of the present disclosure. [Figure 15] FIG. 15 is a diagram for explaining a configuration example of an optical detection system according to an embodiment of the present disclosure. [Figure 16] FIG. 16 is a diagram for explaining another configuration example of an optical detection system according to an embodiment of the present disclosure. [Figure 17] FIG. 17 is a diagram for explaining another configuration example of an optical detection system according to an embodiment of the present disclosure. [Figure 18A] FIG. 18A is a diagram showing an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. [Figure 18B] FIG. 18B is a diagram showing an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. [Figure 18C] FIG. 18C is a diagram showing an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. [Figure 18D] FIG. 18D is a diagram showing an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. [Figure 18E] FIG. 18E is a diagram showing an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. [Figure 18F] FIG. 18F is a diagram showing an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. [Figure 18G] FIG. 18G is a diagram showing an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. [[ID=3-seven]] [Figure 18H] FIG. 18H is a diagram showing an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. [Figure 19] FIG. 19 is a diagram for explaining a configuration example 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 Example 1 of the present disclosure. [Figure 21] FIG. 21 is a diagram for explaining another configuration example of the imaging device according to Modification Example 1 of the present disclosure. [Figure 22] FIG. 22 is a diagram for explaining a configuration example of an imaging device according to Modification Example 2 of the present disclosure. [Figure 23] FIG. 23 is a diagram for explaining a layout example of the imaging device according to Modification Example 2 of the present disclosure. [Figure 24] FIG. 24 is a diagram for explaining a configuration example of an imaging device according to Modification Example 3 of the present disclosure. [Figure 25] FIG. 25 is a diagram for explaining a configuration example of an imaging device according to Modification Example 4 of the present disclosure. [Figure 26] FIG. 26 is a diagram for explaining a configuration example of an imaging device according to Modification Example 5 of the present disclosure. [Figure 27] FIG. 27 is a diagram for explaining a configuration example of the imaging device according to Modification Example 5 of the present disclosure. [Figure 28] FIG. 28 is a diagram for explaining a layout example of the imaging device according to Modification Example 5 of the present disclosure. [Figure 29] FIG. 29 is a diagram for explaining another configuration example of the imaging device according to Modification Example 5 of the present disclosure. [Figure 30] FIG. 30 is a diagram for explaining another configuration example of the imaging device according to Modification Example 5 of the present disclosure. [Figure 31] FIG. 31 is a diagram for explaining a configuration example of an imaging device according to Modification Example 6 of the present disclosure. [Figure 32] FIG. 32 is a diagram for explaining a configuration example of the imaging device according to Modification Example 6 of the present disclosure. [Figure 33] FIG. 33 is a diagram for explaining a configuration example of an imaging device according to Modification Example 7 of the present disclosure. [Figure 34] FIG. 34 is a diagram for explaining a configuration example of the imaging device according to Modification Example 7 of the present disclosure. [Figure 35] FIG. 35 is a diagram for explaining another configuration example of the imaging device according to Modification Example 7 of the present disclosure. [Figure 36] Figure 36 is a diagram illustrating another configuration example of the imaging device according to Modification 7 of this disclosure. [Figure 37] Figure 37 is a diagram illustrating another configuration example of the imaging device according to Modification 7 of this disclosure. [Figure 38] Figure 38 is a diagram illustrating another configuration example of the imaging device according to Modification 7 of this disclosure. [Figure 39] Figure 39 is a block diagram showing an example of the configuration of an electronic device having an imaging device. [Figure 40] Figure 40 is a block diagram showing another example configuration of an electronic device having an imaging device. [Figure 41] Figure 41 is a block diagram showing an example of a schematic configuration of a vehicle control system. [Figure 42] Figure 42 is an explanatory diagram showing an example of the installation location of the external information detection unit and the imaging unit. [Figure 43] Figure 43 is a block diagram showing another example of a schematic configuration of a vehicle control system. [Figure 44] Figure 44 shows an example of a schematic configuration of an endoscopic surgical system. [Figure 45] Figure 45 is a block diagram showing an example of the functional configuration of a camera head and CCU. [Figure 46] Figure 46 is a block diagram showing another example of the functional configuration of the camera head and CCU. [Modes for carrying out the invention]

[0008] The embodiments of this disclosure will be described in detail below with reference to the drawings. The description will be in the following order. 1. Embodiment 2. Variations 3. Examples of application 4. Application Examples

[0009] <1. Embodiment> 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 an embodiment of the present disclosure. Figure 2 is a diagram showing an example of the pixel section of an imaging device according to an embodiment. A photodetector is a device capable of detecting incident light. An imaging device 1, which is an example of a photodetector, has a plurality of pixels P including a photoelectric conversion unit, and is configured to generate a signal by photoelectric conversion of incident light.

[0010] The imaging device 1, as an example, receives light transmitted through an optical system (not shown) including an optical lens and generates a signal. The imaging device 1 is constructed using, for example, a substrate (for example, a semiconductor substrate such as a Si (silicon) substrate or an SOI (silicon on insulator) substrate) on which the photoelectric conversion unit of each pixel P is provided.

[0011] The imaging device 1, as will be described later, has a structure (layered structure) composed of multiple substrates stacked on top of each other. The imaging device 1 has, for example, a photonic integrated circuit (PIC). The imaging device 1 can be manufactured using silicon-containing substrates (silicon substrates, SOI substrates, etc.) and silicon photonics technology.

[0012] 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.

[0013] 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.

[0014] The imaging device 1 (light detection device) is configured, for example, as an image sensor. The imaging device 1 may be, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor. The imaging device 1 can be used in various electronic devices such as digital still cameras, video cameras, and mobile phones.

[0015] As shown in Figure 2, the direction of incidence of light 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.

[0016] [Overall configuration of the imaging device] The imaging device 1, as an example, includes a pixel section 100, a pixel control circuit 105, a processing circuit 200, and an optical circuit 300, as shown in Figure 1. The imaging device 1 is also provided with, for example, a plurality of control lines L1 and a plurality of signal lines L2. The pixel section 100 is a pixel array in which a plurality of pixels P are arranged. The number and arrangement of pixels P in the pixel section 100 (i.e., the pixel array) can be changed as appropriate.

[0017] Control line L1 is a signal line capable of transmitting signals to control pixels P, and is connected to the pixel control circuit 105 and the pixels P of the pixel unit 100. Multiple control lines L1 are wired to each pixel row of the pixel unit 100, for example, each row composed of multiple pixels P arranged horizontally (in the row direction). The control line L1 is configured to transmit control signals for reading signals from the pixels P.

[0018] The multiple control lines L1 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, wiring that transmits signals to control the reset transistor, etc. The control lines L1 can also be called drive lines (or pixel drive lines) that transmit signals to drive the pixels P.

[0019] The signal line L2 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 processing circuit 200. In the pixel unit 100, for example, one or more signal lines L2 are wired for each pixel column, which is composed of multiple pixels P arranged vertically (in the column direction). The signal line L2 is electrically connected to the pixel P and is configured to transmit signals output from the pixel P.

[0020] In the imaging device 1, multiple signal lines L2 may be provided for a single pixel row. For example, the imaging device 1 has multiple signal lines L2 for each pixel row containing multiple pixels P. The number and arrangement of control lines L1 and signal lines L2 in the imaging device 1 are not limited to the illustrated example and can be changed as appropriate.

[0021] The pixel control circuit 105 is configured to control each pixel P of the pixel unit 100. The pixel control circuit 105 (pixel control unit) is composed of multiple circuits, such as a buffer, a shift register, and an address decoder. The pixel control circuit 105 generates a signal for controlling the pixels P and outputs it to each pixel P of the pixel unit 100 via the control line L1.

[0022] The pixel control circuit 105 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 L1. The pixel control circuit 105 can also control the reading of pixel signals from each pixel P. The pixel control circuit 105 can also be described as a pixel driving circuit (pixel driving unit) configured to drive each pixel P.

[0023] The processing circuit 200 is a signal processing circuit (signal processing unit) and is configured to perform signal processing. The processing circuit 200 includes an AD (Analog Digital) conversion circuit and is configured to perform signal processing of the input pixel signal. The processing circuit 200 includes, for example, a load circuit, an AD conversion circuit 20, a horizontal selection switch, etc. The load circuit is, for example, composed of a current source capable of supplying current to the amplification transistor of the pixel P. The load circuit, for example, forms a source follower circuit together with the amplification transistor of the pixel P.

[0024] The processing circuit 200 may have a signal amplification circuit configured to amplify the pixel signal read from the pixel P via the signal line L2. The load circuit, signal amplification circuit, and AD conversion circuit 20, etc., are provided, for example, for each of the multiple signal lines L2. In the imaging device 1, a load circuit, signal amplification circuit, and AD conversion circuit 20, etc., may be provided for each pixel row of the pixel section 100. The AD conversion circuit 20 is an ADC (Analog to Digital Converter).

[0025] The AD conversion circuit 20 is configured to perform AD conversion and converts the input analog signal into a digital signal. The AD conversion circuit 20 (AD conversion unit) performs AD conversion processing on the pixel signal, which is an analog signal input from each pixel P via the signal line L2. The AD conversion circuit 20 includes, as an example, a comparator circuit and a counter, and converts the input pixel signal into a digital signal of a predetermined number of bits.

[0026] The processing circuit 200 includes multiple logic circuits and is composed of, for example, circuits that perform various signal processing on the input pixel signal. The processing circuit 200 is composed of arithmetic circuits, memory circuits, etc. As an example, the processing circuit 200 can perform signal processing on the pixel signal and output the processed pixel signal. The processing circuit 200 can perform various signal processing such as noise reduction processing and interpolation processing.

[0027] The signals output from each pixel P of the pixel unit 100 are input to the processing circuit 200 via the signal line L2. The processing circuit 200 can perform signal processing such as AD conversion of the pixel P signals and CDS (Correlated Double Sampling). The signals from each pixel P transmitted via each signal line L2 are processed by the processing circuit 200 and output to the optical circuit 300.

[0028] The processing circuit 200 also functions as a control circuit (control unit) and is configured to control various parts of the imaging device 1. The processing circuit 200 receives externally supplied clock signals, data commanding the operating mode, etc., and can output data such as internal information of the imaging device 1. The processing circuit 200 includes, for example, a timing generator configured to generate various timing signals.

[0029] The processing circuit 200 controls the operation of the pixel control circuit 105 and the optical circuit 300, etc., based on various timing signals (pulse signals, clock signals, etc.) generated by the timing generator. The processing circuit 200 may include circuits such as a PLL (Phase Locked Loop) and a DAC (Digital to Analog Converter). Furthermore, the processing circuit 200 may be configured to include at least a part of the pixel control circuit 105.

[0030] The optical circuit 300 is configured to convert electrical signals into optical signals and output optical signals. The optical circuit 300 includes, for example, a modulator and a waveguide, and is configured to output (transmit) optical signals based on pixel signals. For example, the optical circuit 300 receives the pixel signals of each pixel P after signal processing from the processing circuit 200.

[0031] The optical circuit 300 is configured to convert the pixel signal, which is an electrical signal input from the processing circuit 200, into an optical signal, and to output the converted pixel signal to the outside. For example, the optical circuit 300 can generate a modulated optical signal based on the pixel signal, which is a digital signal input from the processing circuit 200, and output it to an external device (for example, an image processing device).

[0032] [Pixel composition] Figure 3 shows an example of the circuit configuration of a pixel in an imaging device according to an 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.

[0033] In the example shown in Figure 3, 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 3).

[0039] The source of the transistor AMP is connected to signal line L2, for example, via 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 signal line L2.

[0040] 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 3. The transistor SEL is controlled by the signal SSEL and is configured to output the signal from the transistor AMP to the signal line L2. The transistor SEL can control the timing of the pixel signal output. The transistor SEL is a selection transistor.

[0041] 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 L2. 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 3) is supplied and the transistor AMP. Furthermore, the transistor SEL may be omitted if necessary.

[0042] The transistor RST is configured to reset the voltage of the floating diffusion FD. In the example shown in Figure 3, 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.

[0043] 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, for example, the power line to 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.

[0044] The readout circuit 15 may be configured to allow changing the conversion gain (i.e., conversion efficiency) when converting charge to voltage. For example, the readout circuit 15 may have 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.

[0045] 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.

[0046] 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.

[0047] In the example shown in Figure 3, transistors TG, AMP, SEL, and RST are each composed of NMOS transistors. The transistor for pixel P may be composed of a PMOS transistor if necessary.

[0048] The pixel control circuit 105 (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 L1 described above, and sets the transistors to an ON state (conducting state) or an OFF state (non-conducting state).

[0049] For example, the multiple control lines L1 for each pixel row of the imaging device 1 include 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, wiring that transmits the signal for controlling switching transistors, and so on.

[0050] The transistors TG, SEL, RST, and switching transistors are controlled on and off by the pixel control circuit 105. The pixel control circuit 105 controls the readout circuit 15 for each pixel P, causing each pixel P to output a pixel signal to the signal line L2. The pixel control circuit 105 can control the reading of the pixel signal from each pixel P to the signal line L2.

[0051] Figure 4 shows another example of the pixel circuit configuration of an imaging device according to an embodiment. The imaging device 1 may have a configuration in which multiple pixels P share one readout circuit 15. In the imaging device 1, for example, the readout circuit 15 is provided for multiple pixels P.

[0052] As an example, as shown in Figure 4, a readout circuit 15 may be placed for every four pixels P (referred to as pixels Pa to Pd). Pixels Pa, Pb, Pc, and Pd share one readout circuit 15. For example, a 2x2 pixel array composed of adjacent pixels Pa to Pd shares one readout circuit 15.

[0053] The imaging device 1 is configured to read out the pixel signal of each of the 2x2 pixels by, for example, operating the readout circuit 15 in a time-division manner. The imaging device 1 can also read out a pixel signal which is the sum of the signals of each of the 2x2 pixels. As an example, the imaging device 1 can read out a pixel signal corresponding to the charge obtained by summing the charges converted photoelectrically by each of the 2x2 pixels.

[0054] The photoelectric conversion unit 11 (in the example shown in Figure 4, the photodiode PD of pixel Pa to the photodiode PD of pixel Pd) can perform photoelectric conversion to generate charge according to the amount of light received. The transistor TG (in Figure 4, the transistor TG of pixel Pa to the transistor TG of pixel Pd) is configured to transfer the charge converted photoelectrically by the photoelectric conversion unit 11 to the floating diffusion FD.

[0055] In the example shown in Figure 4, the transistors TG of pixels Pa through Pd are controlled on and off by different signals. The transistor TG of pixel Pa is controlled by signal STG1, and the transistor TG of pixel Pb is controlled by signal STG2. Furthermore, the transistor TG of pixel Pc is controlled by signal STG3, and the transistor TG of pixel Pd is controlled by signal STG4.

[0056] The imaging device 1 may have a configuration in which five or more pixels P, for example eight pixels P, share one readout circuit 15. For example, in the imaging device 1, a readout circuit 15 is provided for every eight pixels P, and the eight pixels P share one readout circuit 15. The configuration of the readout circuit 15 is not limited to the illustrated example and can be changed as appropriate.

[0057] [Configuration of the imaging device] Figure 5 shows an example of a cross-sectional configuration of an imaging device according to an embodiment. The imaging device 1 has, for example, a substrate 201, a substrate 202, and a substrate 203, as shown in the example in Figure 5. The imaging device 1 has, as an example, a configuration in which the substrates 201, 202, and 203 are stacked in the Z-axis direction.

[0058] Each of the substrates 201, 202, and 203 is constructed using a semiconductor substrate such as a silicon substrate or an SOI substrate. Substrates 201, 202, and 203 may also be constructed using a SiGe (silicon germanium) substrate, a SiC (silicon carbide) substrate, or other materials.

[0059] In the example shown in Figure 5, substrate 201 has layer 101 and wiring layer 111. Substrate 202 has layer 102, wiring layer 121 and wiring layer 122. Substrate 203 has layer 103, layer 104, wiring layer 131 and layer 132. Layers 101, 102, 103, and 104 are, for example, semiconductor layers.

[0060] Layers 101, 102, 103, and 104 are also referred to as semiconductor layer 101, semiconductor layer 102, semiconductor layer 103, and semiconductor layer 104. Note that layer 132 of the substrate 203 is configured to have a refractive index lower than, for example, the refractive index of semiconductor layer 103. Layer 132 can be formed using a material having a refractive index lower than the refractive index of the optical waveguide (such as waveguide 71 or waveguide 72 described later) provided in semiconductor layer 103.

[0061] Layer 132 may be composed of silicon oxide (SiO), or it may be formed using other insulating materials. For example, layer 132 may be composed of a BOX (Buried Oxide) layer in an SOI substrate. Layer 132 can also be called an insulating layer (insulating layer) or a material layer. Furthermore, layer 132 may be composed of a low refractive index material and can also be called a low refractive index material layer.

[0062] Furthermore, wiring, electrodes, etc., may be provided in layer 132 of the substrate 203 as needed. For example, wiring (or electrodes) that penetrate layer 132 may be formed for mounting circuit elements on the back side of the semiconductor layer 103. Layer 132 may be a layer with wiring, and can also be called a wiring layer.

[0063] In the example shown in Figure 5, the semiconductor layer 101, wiring layer 111, wiring layer 121, semiconductor layer 102, wiring layer 122, wiring layer 131, semiconductor layer 103, layer 132, and semiconductor layer 104 are provided from the side into which light from the object to be measured is incident. The substrate 201 including the semiconductor layer 101 is provided with, for example, a photoelectric conversion unit 11, a readout circuit 15, and the like.

[0064] As shown in Figure 5, the semiconductor layer 101 of substrate 201 has opposing surfaces 11S1 and 11S2. Surface 11S2 is the surface opposite to surface 11S1. Surface 11S2 is, for example, a light-receiving surface (light incident surface). The semiconductor layer 102 of substrate 202 has opposing surfaces 12S1 and 12S2. Surface 12S2 is the surface opposite to surface 12S1.

[0065] The semiconductor layer 103 of the substrate 203 has opposing surfaces 13S1 and 13S2. Surface 13S2 is the surface opposite to surface 13S1. Surfaces 11S1, 12S1, and 13S1 are, for example, element formation surfaces on which elements such as transistors are formed. Surfaces 11S1 and 12S1 are provided with gate electrodes, gate insulating films (e.g., gate oxide films), etc.

[0066] In the semiconductor layer 101, a plurality of photoelectric conversion units 11 are provided along surfaces 11S1 and 11S2 of the semiconductor layer 101. The photoelectric conversion unit 11 is a photoelectric conversion element, and can also be called a photoelectric conversion region. For example, a plurality of photoelectric conversion units 11 are embedded in the semiconductor layer 101. The photoelectric conversion unit 11 is provided between surfaces 11S1 and 11S2 of the semiconductor layer 101.

[0067] On the surface 11S2 side of the semiconductor layer 101, for example, a lens 17 and a filter 18 are provided. The lens 17 is a lens that focuses light and is an optical component also called an on-chip lens. The lens 17 (lens portion) is provided, for example, above the photoelectric conversion unit 11 for each pixel P or for each of a group of pixels P.

[0068] Light from the subject to be measured enters the lens 17, for example, through an optical system such as an imaging lens. The lens 17 guides the incident light towards the photoelectric conversion unit 11 of the pixel P. The photoelectric conversion unit 11 of the pixel P converts the incident light, which enters through the lens 17 and filter 18, into photoelectric energy. The photoelectric conversion unit 11 absorbs the incident light and generates an electric charge.

[0069] The filter 18 is configured to selectively transmit light in a specific wavelength range from the incident light. The filter 18 can be a primary color system (RGB), a complementary color system (CMY), or a filter that transmits infrared light. The filter 18 is provided, for example, above the photoelectric conversion unit 11 for each pixel P or for each set of pixels P. As an example, the filter 18 is formed between the lens 17 and the semiconductor layer 101.

[0070] The filter 18 is provided, for example, on the surface 11S2 side of the semiconductor layer 101 for each pixel P or for each set of pixels P. In the imaging device 1, the filter 18 may be omitted if necessary. The filter 18 may not be provided for some or all of the pixels P in the imaging device 1. For example, the filter 18 may not be provided for pixels P that receive white (W) light and perform photoelectric conversion.

[0071] In the example shown in Figure 5, the lens 17 and filter 18 are stacked on the semiconductor layer 101 in the thickness direction perpendicular to the surface 11S2 of the semiconductor layer 101. The lens 17 and filter 18 are provided on the side into which light from the optical system is incident, and the wiring layer 111 is provided on the side opposite to the side into which light is incident. The imaging device 1 is configured, for example, as a so-called back-illuminated imaging device.

[0072] On the surface 11S1 side of the semiconductor layer 101, for example, transistors TG, floating diffusion FD, etc. are provided. Also, for example, at least some of the transistors of the readout circuit 15 (transistor AMP, transistor SEL, transistor RST, etc.) are provided on the surface 11S1 side of the semiconductor layer 101.

[0073] A wiring layer 111 is provided on the surface 11S1 side of semiconductor layer 101. A wiring layer 121 is provided on the surface 12S1 side of semiconductor layer 102, and a wiring layer 122 is provided on the surface 12S2 side of semiconductor layer 102. In addition, a wiring layer 131 is provided on the surface 13S1 side of semiconductor layer 103, and a layer 132 is provided on the surface 13S2 side of semiconductor layer 103.

[0074] Each of the wiring layers 111, 121, 122, and 131 includes, for example, a conductive film and an insulating film, and has multiple wirings and multiple vias, etc. Each of the wiring layers 111, 121, 122, and 131 has a configuration in which multiple wirings are laminated via an insulating film, for example, an interlayer insulating film (interlayer insulating layer). Each of the wiring layers 111, 121, 122, and 131 is configured as a multilayer wiring layer and may contain two or more or three or more layers of wiring.

[0075] Each of the wirings in wiring layers 111, 121, 122, and 131 may be formed using a metallic material such as aluminum (Al), copper (Cu), or tungsten (W), or may be made of polysilicon (Poly-Si) or other conductive materials. The interlayer insulating film may be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), or other insulating materials. Layer 132 may also be configured as a wiring layer having multiple wirings.

[0076] In the example shown in Figure 5, wiring layer 111 has multiple electrodes 91, wiring layer 121 has multiple electrodes 92, wiring layer 122 has multiple electrodes 93, and wiring layer 131 has multiple electrodes 94. Electrodes 91, 92, 93, and 94 are, for example, electrodes formed using copper (Cu).

[0077] Electrodes 91, 92, 93, and 94 are electrodes used for joining metal electrodes, and can also be called joining electrodes. Electrodes 91, 92, 93, and 94 may be made of metal materials other than copper, such as nickel (Ni), cobalt (Co), gold (Au), tin (Sn), etc., or other materials.

[0078] As an example, substrates 201 and 202 are bonded together by a bond between metal electrodes made of Cu (electrode 91, electrode 92), i.e., a Cu-Cu bond. Circuits provided on substrate 201 and circuits provided on substrate 202 are electrically connected via electrodes 91 and 92.

[0079] As an example, substrates 201 and 202 are stacked such that surfaces 11S1 and 12S1, on which elements such as transistors are formed by bonding between electrodes, face each other. That is, substrates 201 and 202 are bonded together such that the surface of semiconductor layer 101 and the surface of semiconductor layer 102 face each other.

[0080] Furthermore, for example, the substrates 202 and 203 are bonded together by a bond between electrodes 93 and 94, which are metal electrodes made of Cu, i.e., a Cu-Cu bond. The circuits provided on substrate 202 and the circuits provided on substrate 203 are electrically connected via electrodes 93 and 94.

[0081] As an example, substrates 202 and 203 are stacked by bonding between electrodes such that surfaces 12S2 and 13S1 face each other. That is, substrates 202 and 203 are bonded so that the back surface of semiconductor layer 102 and the front surface of semiconductor layer 103 face each other. Alternatively, substrates 201, 202, and 203 may be stacked using bumps.

[0082] The imaging device 1 is provided with a through-electrode 80, for example, as shown in the example in Figure 5. The through-electrode 80 is a connecting electrode (i.e., a connection part) that connects circuits (elements) provided in different layers. As an example, the through-electrode 80 is provided in the substrate 202 so as to penetrate the semiconductor layer 102.

[0083] In the example shown in Figure 5, the through-electrode 80 extends in the thickness direction (i.e., the Z-axis direction) of the substrate 202 in the semiconductor layer 102 and the wiring layer 122, and is connected to electrode 93. The through-electrode 80 and electrodes 93, 94, etc., electrically connect the circuit elements provided on the substrate 202 to the circuit elements provided on the substrate 203.

[0084] The imaging device 1 is configured to have a plurality of through electrodes 80, as shown in the example in Figure 5 or Figure 6, corresponding to the number of signals transmitted between substrates 202 and 203. The through electrodes 80 are formed using a metallic material such as tungsten, aluminum, or copper. However, the through electrodes 80 may be made of other metallic materials.

[0085] In the imaging device 1, for example, the photoelectric conversion unit 11 and readout circuit 15 for each pixel P are provided on the substrate 201. The processing circuit 200 (see Figure 1), which includes the AD conversion circuit 20 described above, is provided on the substrate 202, which includes the semiconductor layer 102, for example. The optical circuit 300 is provided on the substrate 203. The pixel control circuit 105 described above is provided on the substrate 202 or the substrate 201.

[0086] The readout circuit 15 generates a pixel signal based on the charge converted by the photoelectric conversion unit 11 and outputs it to the processing circuit 200 on the substrate 202 via the signal line L2. The processing circuit 200 performs signal processing (such as AD conversion) on the pixel signal of each pixel P and can output the processed pixel signal to the optical circuit 300 on the substrate 203.

[0087] The optical circuit 300 is provided on a substrate 203 including, for example, layers 103 and 104. Each of layers 103 and 104 is, for example, a semiconductor layer, and may be a silicon layer. Layers 103 and 104 may each be made of other semiconductor materials or other materials.

[0088] The semiconductor layer 103 may be composed of, for example, a silicon layer (i.e., an active layer) on a BOX (Buried Oxide) layer in an SOI substrate. The optical circuit 300 is formed, for example, using silicon photonics technology, and can also be called a silicon photonics circuit. The substrate 203 on which the optical circuit 300 is formed can also be called a silicon photonics substrate.

[0089] The optical circuit 300 includes, for example, a light source 30, a modulator 40, a waveguide 71, and a waveguide 72. The optical circuit 300 may also have a photodetector 50. Furthermore, the optical circuit 300 may also have an antenna, a distributor, a wavelength filter, etc. The light source 30 is provided on the same substrate (for example, substrate 203) together with the modulator 40, etc., and is mounted on the imaging device 1. The light source 30 may also be provided outside the imaging device 1.

[0090] The light source 30, modulator 40, and photodetector 50 are provided on the substrate 203, for example, as shown in Figure 5. In the example shown in Figure 5, the light source 30, modulator 40, and photodetector 50 are provided on the semiconductor layer 103 and the wiring layer 131. It can also be said that the light source 30, modulator 40, and photodetector 50 are arranged on the semiconductor layer 103.

[0091] The light source 30 is configured to generate and output light. The light source 30 (light source unit) is configured to include, for example, one or more light-emitting elements 31. The light-emitting elements 31 are LDs (Laser Diodes) or the like, and can output light to the outside. The light source 30 is electrically connected to a circuit that controls the light source 30 (for example, a processing circuit 200) via electrodes 93 and 94, for example.

[0092] The light source 30 has, for example, a light-emitting element 31 which is a semiconductor laser element, and is configured to output laser light as output light. The light-emitting element 31 is, for example, made of a III-V compound semiconductor material (such as InP (indium phosphide), GaAs (gallium arsenide), etc.) and has a structure in which a p-type cladding layer, an active layer, and an n-type cladding layer are stacked. The light source 30 can generate laser light and emit laser light.

[0093] Waveguide 71 is, for example, a Si (silicon) waveguide and is provided in semiconductor layer 103. Waveguide 71 is configured to guide incoming (incident) light. Waveguide 71 transmits, for example, light incident from light-emitting element 31 of light source 30. Waveguide 71 is configured to transmit (propagate) light from light source 30 to modulator 40.

[0094] The output light from the light source 30 is transmitted to the modulator 40, for example, via a waveguide 71. The waveguide 71 may be made of other semiconductor materials. The waveguide 71 may be formed using other materials having a higher refractive index than the surrounding components (for example, the insulating film of the wiring layer 131, the insulating film of layer 132). The arrangement and shape of the waveguide 71 are not limited to the illustrated example and can be changed as appropriate.

[0095] The modulator 40 is configured to convert electrical signals into optical signals and output optical signals. The modulator 40 is a modulation circuit (modulation unit) and is configured to output an optical signal modulated based on an input electrical signal (e.g., a pixel signal). For example, the output light from the light source 30 is input (incident) to the modulator 40 via the waveguide 71. In addition, the modulator 40 receives a pixel signal, which is a digital signal, from the processing circuit 200 via wiring and through electrodes 80, etc.

[0096] The modulator 40 is configured to modulate the light transmitted from the light source 30 based on the pixel signal supplied from the processing circuit 200. The modulator 40 can, for example, modulate the light (intensity modulation or phase modulation) according to the value (pixel value) of the pixel signal, which is a digital signal, and output the modulated light, i.e., an optical signal based on the pixel signal.

[0097] The modulator 40 generates, for example, a converted pixel signal that is a light (laser light) modulated according to the pixel signal, which is a digital signal, i.e., an optical signal indicating the pixel value. As an example, the pixel signals of each pixel P transmitted from the processing circuit 200 are sequentially converted into optical signals by the modulator 40 and output (transmitted) to the outside via the waveguide 72.

[0098] Waveguide 72 is, for example, a silicon waveguide and is provided in semiconductor layer 103. Waveguide 72 is configured to guide incoming (incident) light. Waveguide 72 transmits light (e.g., modulated laser light) incident from modulator 40 to the outside. Waveguide 72 may be made of other semiconductor materials. Waveguide 71 may be formed using other materials having a refractive index higher than that of surrounding materials (e.g., insulating film of wiring layer 131, insulating film of layer 132).

[0099] A transmission path 75 is optically connected to the waveguide 72, for example, as schematically shown in Figure 7. The transmission path 75 is an optical transmission path and is made of, for example, an optical fiber. The transmission path 75 has, as an example, a core and a cladding with different refractive indices. The transmission path 75 may be configured to have one or more cores and one or more cladding.

[0100] A modulated optical signal is input to the transmission line 75 from the modulator 40 of the optical circuit 300. The optical signal output from the modulator 40 is transmitted (propagated) to an external device (e.g., an image processing device) via, for example, the waveguide 72 and the transmission line 75 connected to the waveguide 72. Note that communication of optical signals between the optical circuit 300 of the imaging device 1 and the external device may be performed wirelessly.

[0101] The photodetector 50 is configured to receive (receive) optical signals. The photodetector 50 is a light-receiving circuit and is configured to include one or more light-receiving elements 51. The light-receiving elements 51 are, for example, photodiodes (PDs) and are configured to receive optical signals. The light-receiving elements 51 may be made of germanium photodiodes (GePDs). As an example, the light-receiving elements 51 are provided on the surface 13S1 of the semiconductor layer 103.

[0102] The photodetector 50 is configured to receive an optical signal and convert the optical signal into an electrical signal. The photodetector 50 is configured to receive the optical signal via the transmission line 75 shown in Figure 7 or another transmission line. The photodetector 51 receives light, generates an electric charge through photoelectric conversion, and can output an electric current. The photodetector 51 outputs a signal based on the received optical signal.

[0103] In the imaging device 1, for example, in response to the reception of an optical signal from an external device, a signal corresponding to the photocurrent flowing through the photodetector 51 is generated and output to an amplification circuit (not shown). The amplification circuit is electrically connected to a photodetector 50, for example, and is configured to output a signal based on the photocurrent generated by the photodetector 50.

[0104] The amplification circuit is configured using, for example, a transimpedance amplifier (TIA). The amplification circuit can convert the current signal detected by the photodetector 50 into a voltage signal and output the voltage signal to the processing circuit 200. The optical circuit 300 may include an amplification circuit (e.g., a TIA circuit). The photodetector 50 and the amplification circuit together can also be referred to as the light receiving circuit or detection circuit.

[0105] The processing circuit 200 performs, for example, AD conversion processing on the signal input from the amplification circuit. The processing circuit 200 receives signals from external devices (external circuits) via the photodetector 50 and the amplification circuit, etc., and can obtain signals related to the control of the imaging device 1 (for example, signals indicating the operating mode, signals indicating imaging conditions, etc.). The imaging device 1 can transmit and receive optical signals, for example, through one or more transmission lines 75.

[0106] Figure 8 is a diagram illustrating an example layout of an imaging device according to an embodiment. Figure 8(A) shows an example layout on the substrate 201 of the imaging device 1. Figure 8(B) shows an example layout on the substrate 202 of the imaging device 1. Figure 8(C) shows an example layout on the substrate 203 of the imaging device 1.

[0107] As shown in Figure 8(A), the substrate 201 is provided with, for example, a pixel section 100 (i.e., a pixel array). On the substrate 201, as an example, a plurality of pixels P, each containing a photoelectric conversion section 11, are arranged in the X-axis direction and the Y-axis direction. On the substrate 202, for example, a processing circuit 200 is provided, as shown in the example in Figure 8(B).

[0108] As shown in the example in Figure 8(C), for example, an optical circuit 300 is provided on substrate 203. Electrode regions 85 are also provided on substrates 202 and 203. The electrode region 85 is the area where the aforementioned through-electrodes 80 are provided. Multiple through-electrodes 80 are provided in the electrode region 85, corresponding to the number of signals to be transmitted. On substrate 202, for example, an electrode region 85 containing multiple through-electrodes 80 is provided in the area surrounding the processing circuit 200.

[0109] As shown in the example in Figure 8(B), the electrode region 85 is provided, for example, at the end (side) of the processing circuit 200. The electrode region 85 has, for example, a plurality of through electrodes 80 arranged in the Y-axis direction in a plan view (for example, when viewed in the XY plane). On the substrate 203, the electrode region 85 is provided, for example, in the peripheral region of the optical circuit 300. For example, as shown in the example in Figure 8(C), the electrode region 85 is provided at the end (side) of the optical circuit 300.

[0110] The multiple through-electrodes 80 provided in the imaging device 1 include, for example, a through-electrode 80 that transmits pixel signals from the processing circuit 200, a through-electrode 80 that transmits signals to control the optical circuit 300 (modulator 40, photodetector 50, etc.), a through-electrode 80 that transmits signals from the photodetector 50 and an amplification circuit (e.g., a TIA circuit).

[0111] The optical circuit 300 of the imaging device 1 may include an optical multiplexer / demultiplexer, a switch, a distributor, a wavelength filter, etc. The optical circuit 300 may, for example, have an AWG (Arrayed Waveguide Grating) as an optical multiplexer / demultiplexer and be configured to enable Wavelength Division Multiplexing (WDM) communication.

[0112] The optical circuit 300 may include, for example, multiple switches (optical switches) and be configured to select (switch) the transmission path (waveguide) to which the optical signal is transmitted. The optical circuit 300 may also be configured to broadcast signals simultaneously to multiple external chips (for example, multiple APs (Application Processors)).

[0113] Figure 9 is a diagram illustrating an example of the configuration of the optical circuit of an imaging device according to an embodiment. The optical circuit 300 is composed of a plurality of modulators 40 and a distributor 41. The modulators 40 are, for example, wavelength-selective modulators (e.g., ring modulators). The light source 30 may be provided inside the imaging device 1 or outside the imaging device 1. Figure 9 schematically shows an example where the light source 30 is provided as an external light source.

[0114] In the example shown in Figure 9, the output light from the light source 30, which acts as an external light source, is input to the distributor 41 via the transmission line 75. The light from the light source 30 is distributed to two lanes by the distributor 41 and modulated in each of the multiple modulators 40 (four modulators 40 in Figure 9) in each lane, for example, according to the pixel signal of each pixel P. The optical circuit 300 can output the optical signals modulated by each modulator 40 to the outside via the transmission line 75.

[0115] The transmission path 75 may include, for example, multiple optical fibers (optical fibers between the external light source and the optical circuit 300, optical fibers between the optical circuit 300 and external devices, etc.) and be configured as a group of transmission paths. It can also be said that there are transmission paths 75 that transmit the output light from the light source 30 as an external light source to the optical circuit 300, and transmission paths 75 that transmit the optical signals modulated by the optical circuit 300 to external devices.

[0116] Figure 10 is a diagram illustrating another example of the configuration of the optical circuit of the imaging device according to the embodiment. The optical circuit 300 is composed of a plurality of modulators 40, a demultiplexer 42, and a multiplexer 43. The modulators 40 are configured, for example, using a Mach-Zehnder interferometer. Figure 10 schematically shows an example in which the light source 30 is provided as an external light source.

[0117] In the example shown in Figure 10, the output light from the light source 30, which acts as an external light source, is input to the demultiplexer 42 via the transmission line 75. The light from the light source 30 is separated (branched) into three lanes by the demultiplexer 42, i.e., wavelength-separated, and modulated in each of the three modulators 40 according to the pixel signal of each pixel P, for example. The optical signals modulated by each modulator 40 are combined (coupled) by the multiplexer 43, i.e., wavelength-combined, and output to the outside via the transmission line 75.

[0118] As shown in the example in Figure 8(C), the substrate 203 is provided with, for example, a modulator 40, a photodetector 50, a circuit region 86, a circuit region 87, and a light source 30. The circuit region 86 is provided with, for example, the distributor 41, demultiplexer 42, multiplexer 43, switch, wavelength filter, etc. The circuit region 87 is provided with, for example, a plurality of waveguides (i.e., waveguide wiring), such as waveguide 71 and waveguide 72.

[0119] Furthermore, the optical circuit 300 may have a spot size converter 74 (SSC), as shown in Figure 8(C). The spot size converter 74 is provided on the substrate 203 between the circuit region 87 including waveguides 71 and 72 and the transmission line 75 (optical fiber), for example, as shown in the example in Figure 8(C).

[0120] The processing circuit 200 may have an I / F (interface) circuit 25, as shown in Figure 8(B). The I / F circuit 25 is configured to control the driving of, for example, a modulator 40 and a photodetector 50. The I / F circuit 25 can also be called an I / F driving circuit (or optical I / F circuit). The I / F circuit 25 is configured to output the pixel signal of each pixel P after signal processing to the modulator 40 on the substrate 203 via the through-electrode 80 in the electrode region 85.

[0121] As shown in the examples in Figures 8(B) and 8(C), the modulator 40 and the photodetector 50 are arranged on the substrate 203, for example, directly below the I / F circuit 25 on the substrate 202. In this case, the wiring distance between the I / F circuit 25 and the modulator 40 (or photodetector 50) can be minimized. The I / F circuit 25 may be provided so as to overlap at least a portion of the modulator 40 or photodetector 50 when viewed from above the substrate 202.

[0122] By configuring the imaging device 1 in this way, signal transmission between the processing circuit 200 and the optical circuit 300 can be efficiently performed by the I / F circuit 25 and the through-electrode 80 of the electrode region 85. Signal delay and signal attenuation in the transmission path between the processing circuit 200 and the optical circuit 300, which acts as an optical communication circuit, can be suppressed. Alternatively, either the modulator 40 or the photodetector 50, for example, only the modulator 40, may be placed directly below the I / F circuit 25.

[0123] In the imaging device 1, the modulator 40 may be positioned such that its long side intersects (e.g., orthogonally) with the direction of the through-electrode 80 (i.e., the Y-axis direction), as shown in the example in Figure 11 or Figure 12. For example, the pixel signal transmitted through the through-electrode 80 can be input from the end (e.g., the left end) of the modulator 40 (e.g., a Mach-Zehnder interferometer), thereby suppressing a decrease in modulation accuracy.

[0124] Figure 13 is a diagram illustrating another layout example of the imaging device according to the embodiment. Figure 13(A) shows an example layout on the substrate 201 of the imaging device 1. Figure 13(B) shows an example layout on the substrate 202 of the imaging device 1. Figure 13(C) shows an example layout on the substrate 203 of the imaging device 1.

[0125] The processing circuit 200 of the imaging device 1 may be provided on separate substrates 202 and 203. This increases the area of ​​the region where the processing circuit 200 is located. For example, as shown in Figures 13(B) and 13(C), a portion of the processing circuit 200 is provided on substrate 202, and another portion is provided on substrate 203. This makes it possible to increase the area of ​​the processing circuit 200.

[0126] The imaging device 1 according to this embodiment has an optical circuit 300 as described above. Therefore, it is possible to perform communication using optical signals and to efficiently transmit signals. The imaging device 1 can communicate with the outside using optical signals and can efficiently transmit signals from the imaging device 1 to the outside. For example, the imaging device 1 can transmit the pixel signals of each pixel P processed by the processing circuit 200 to the outside at high speed.

[0127] As described above, the imaging device 1 has a structure composed of multiple substrates stacked on top of each other. The optical circuit 300 is provided stacked on the substrate on which the processing circuit 200 is located. This allows for a shorter wiring distance between the processing circuit 200 and the optical circuit 300, thereby suppressing signal delays and increased power consumption caused by parasitic capacitance. Furthermore, it is possible to integrate optical communication elements while avoiding an increase in package area, for example.

[0128] Furthermore, the optical detection device (imaging device 1) according to this disclosure enables the use of optical signals for communication within a package during chiplet integration, as well as for communication within a chip, thereby enabling efficient signal transmission. In addition, as in the example described above, when the pixel unit 100, processing circuit 200, and optical circuit 300 are arranged on multiple substrates, it becomes possible to optimize the process for each substrate.

[0129] Figures 14 and 15 are diagrams illustrating an example configuration of a photodetection system according to an embodiment. The photodetection system 10 includes, for example, an imaging device 1 which is an example of a photodetection device, and one or more external devices 2. The external device 2 may be, for example, a semiconductor chip or an AP (Application Processor).

[0130] External device 2, for example, has a processor and memory (ROM, RAM, etc.) and is configured to perform various signal processing tasks. External device 2 is composed of, for example, a GPU (Graphics Processing Unit), a CPU (Central Processing Unit), and memory (ROM, RAM, etc.). The light detection system 10 may be configured to include multiple external devices 2 (external devices 2a to 2c in Figure 15).

[0131] External device 2 has an optical circuit 310, as shown in Figure 14 or Figure 15. The optical circuit 310 has, for example, a photodetector (photodetector) and is configured to receive optical signals. Also, for example, the optical circuit 310 has a modulator (modulation circuit) and is configured to convert electrical signals into optical signals and output them. The optical circuit 310 may have the same circuit (photodetector, modulator, etc.) as the optical circuit 300 of imaging device 1 described above.

[0132] As an example, the imaging device 1 is connected to multiple transmission lines 75 (transmission lines 75a to 75c in Figure 15). In the example shown in Figure 15, the imaging device 1 is connected to an external device 2a having a GPU, an external device 2b having memory, and an external device 2c having a CPU by transmission lines 75a, 75b, and 75c (for example, optical fibers).

[0133] The processing circuit 200 of the imaging device 1 and the circuits (GPU, memory, or CPU) of the external device 2 communicate signals via, for example, optical circuits 300 and 310. In the example shown in Figure 15, the optical circuit 300 of the imaging device 1 communicates optical signals with the optical circuit 310 of the external device 2a via transmission line 75a. The optical circuit 300 also communicates optical signals with the optical circuit 310 of the external device 2b via transmission line 75b, and with the optical circuit 310 of the external device 2c via transmission line 75c.

[0134] The optical detection system 10 can transmit and receive optical signals using the imaging device 1 and the external device 2, each having an optical circuit as an optical interface, enabling efficient signal transmission. For example, it becomes possible to efficiently process large amounts of information in real time. Furthermore, it is possible to prevent an increase in power consumption when signal transmission is increased in speed or distance.

[0135] In the photodetection system 10 according to this embodiment, communication can be performed appropriately even when the distance between the imaging device 1 and the external device 2 (e.g., AP) is long and high-resolution and high-frame-rate data transfer is performed (e.g., for autonomous driving). This makes it possible to realize a photodetection device and photodetection system that enable suitable communication.

[0136] Figures 16 and 17 illustrate another configuration example of the photodetection system according to the embodiment. The photodetection system 10 may be configured to enable communication using optical signals and communication using electrical signals between the imaging device 1 and the external device 2. For example, the imaging device 1 and the external device 2 are configured to transmit and receive optical signals via a transmission line 75 (optical fiber) and to transmit and receive electrical signals via a transmission line 76 (e.g., an electric wire).

[0137] The imaging device 1 may be connected to multiple transmission lines 75 (transmission lines 75a to 75c in Figure 17) and multiple transmission lines 76 (transmission lines 76a to 76c in Figure 17). Each transmission line 76 is, for example, made of an electrical signal cable that corresponds to the communication of electrical signals. The imaging device 1 communicates with the external device 2a using optical signals via transmission line 75a and with the external device 2a using electrical signals via transmission line 76a.

[0138] Furthermore, in the example shown in Figure 17, the imaging device 1 communicates with the external device 2b using optical signals via transmission line 75b, and with the external device 2b using electrical signals via transmission line 76b. In addition, the imaging device 1 communicates with the external device 2c using optical signals via transmission line 75c, and with the external device 2c using electrical signals via transmission line 76c.

[0139] As an example, the light detection system 10 may use optical signals to transmit pixel signals from the imaging device 1 to the external device 2, and electrical signals to transmit signals (e.g., control signals) from the external device 2 to the imaging device 1. Examples of control signals transmitted from the external device 2 to the imaging device 1 include control signals related to the operating mode and control signals related to imaging conditions.

[0140] The optical circuit 300 of the imaging device 1 may have only the modulator 40 among the modulator 40 and photodetector 50 described above. Similarly, the optical circuit 310 of the external device 2 may have only the photodetector 50 among the modulator 40 and photodetector 50 described above. This makes it possible to reduce the circuit area and power consumption of the optical circuits 300 and 310. The imaging device 1 and the external device 2 may be configured to transmit and receive optical signals via wireless communication.

[0141] Figures 18A to 18H show an example of a manufacturing method for an imaging device according to an embodiment. As shown in Figure 18A, photoelectric conversion units 11 and elements such as transistors are formed on the semiconductor layer 101 for each pixel P. In addition, a wiring layer 111 including electrodes 91 and wiring is formed on the surface 11S1 of the semiconductor layer 101.

[0142] Furthermore, as shown in Figure 18B, transistors and other components of the processing circuit 200 are formed on the semiconductor layer 102, and a wiring layer 121 including electrodes 92 and wiring is formed on the surface 12S1 of the semiconductor layer 102. Then, the semiconductor layer 101 with the wiring layer 111 and the semiconductor layer 102 with the wiring layer 121 are placed facing each other, and the substrate 201 and the substrate 202 are joined together as shown in Figure 18C. After that, the thickness of the semiconductor layer 102 is reduced (thinned).

[0143] Next, as shown in Figure 18D, a wiring layer 122 is formed on the surface 12S2 of the semiconductor layer 102, and through electrodes 80 and 93 are formed. A substrate 203 having a semiconductor layer 103 is also prepared. Then, as shown in Figure 18E, each element of the optical circuit 300, such as a light source 30, modulator 40, and photodetector 50, is formed on the surface 131S1 side of the semiconductor layer 103.

[0144] Furthermore, as shown in Figure 18E, a wiring layer 131 including electrodes 94 and wiring is formed on the surface 13S1 of the semiconductor layer 103. Then, the semiconductor layer 102 on which the wiring layer 122 is provided and the semiconductor layer 103 on which the wiring layer 131 is provided are placed facing each other, and the substrate 202 and the substrate 203 are joined together as shown in Figure 18F. After that, the thickness of the semiconductor layer 101 is reduced.

[0145] Next, as shown in Figure 18G, a filter 18 and a lens 17 are formed on the surface 11S2 side of the semiconductor layer 101. After that, the chips are separated (i.e., separated into individual components), and the transmission line 75 (optical fiber) is mounted as shown in Figure 18H. The imaging device 1 shown in Figures 5 to 7 can be manufactured using the above manufacturing method. Note that the above-described manufacturing method for the imaging device is merely an example, and other manufacturing methods may be used.

[0146] [Effects / Effects] The photodetector according to this embodiment comprises a first substrate (e.g., substrate 201) having a photoelectric conversion element that converts light into photoelectric energy, a second substrate (e.g., substrate 202) laminated with the first substrate and having at least a part of a processing circuit (processing circuit 200) capable of performing signal processing on a first signal (e.g., pixel signal) generated based on the charge converted by the photoelectric conversion element, and an optical circuit (optical circuit 300) capable of outputting a first optical signal based on the first signal.

[0147] The photodetector (imaging device 1) according to this embodiment includes a substrate 201 having a photoelectric conversion unit 11, a substrate 202 having at least a part of a processing circuit 200, and an optical circuit 300 capable of outputting an optical signal based on a pixel signal. Therefore, the imaging device 1 can perform communication using optical signals. This makes it possible to realize a photodetector that enables suitable communication.

[0148] 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.

[0149] <2. Variant> (2-1. Variation 1) Figure 19 is a diagram illustrating an example configuration of an imaging device according to Modification 1 of the present disclosure. The imaging device 1 may have a light-shielding member 60, as shown in the example in Figure 19. The light-shielding member 60 is a light-shielding portion (light-shielding film) composed of a light-blocking material. As shown in the example in Figure 19, the light-shielding member 60 is provided above the optical circuit 300 to suppress unwanted light from entering each element of the optical circuit 300.

[0150] The light-shielding member 60 is provided, for example, above the optical circuit 300, so as to cover the optical circuit 300. In the example shown in Figure 19, the light-shielding member 60 is formed on the substrate 203 and is located between the substrate 202 on which the processing circuit 200 is provided and the optical circuit 300. The light-shielding member 60 may be formed to cover all or part of the optical circuit 300 in a plan view (i.e., when viewed in the XY plane).

[0151] The light-shielding member 60 is provided, for example, to cover the modulator 40 of the optical circuit 300. Alternatively, the light-shielding member 60 may be provided to cover the light source 30 having the light-emitting element 31 and the light receiver 50 having the light-receiving element 51. The light-shielding member 60 may also be arranged to cover only a part of the optical circuit 300 (for example, one or two of the modulator 40, light receiver 50, and light source 30).

[0152] The light-shielding member 60 may be made of, for example, the wiring of the wiring layer 131. The light-shielding member 60 may be made of, for example, aluminum (Al), tungsten (W), etc. The light-shielding member 60 may also be made of other light-shielding metal materials, such as copper (Cu). The light-shielding member 60 may be made of a metal compound. The light-shielding member 60 may be made of a light-absorbing material.

[0153] In the imaging device 1, the light-shielding member 60 is provided to suppress unwanted light, as schematically shown by the dashed arrow A1 in Figure 20, from entering the modulator 40 and photodetector 50 of the optical circuit 300. This prevents external light from adversely affecting the optical circuit 300. For example, it is possible to suppress light from the subject being measured from passing through the substrate 201 and other components and entering the modulator 40, thereby suppressing noise from being mixed into the pixel signal. This makes it possible to prevent a deterioration in the quality of the pixel signal.

[0154] Figure 21 is a diagram illustrating another configuration example of the imaging device according to Modification 1. As shown in the example in Figure 21, the light-shielding member 60 may be provided in multiple layers. In the example shown in Figure 21, the light-shielding member 60 is provided in two of the wiring layers 131. The light-shielding member 60 may be formed in multiple layers and have an alternating structure. A high light-shielding effect can be achieved while ensuring gaps for wiring.

[0155] In the imaging device 1 according to this modified example, the provision of a light-shielding member 60 suppresses the incidence of unwanted light onto the light source 30, modulator 40, photodetector 50, or amplification circuit (TIA circuit), etc., thereby suppressing, for example, a decrease in the characteristics of the optical circuit 300 (a decrease in modulation accuracy, a decrease in the accuracy of conversion to digital signals, etc.).

[0156] (2-2. Variation 2) Figure 22 is a diagram illustrating an example configuration of the imaging device according to Modification 2. Figure 23 is a diagram illustrating an example layout of the imaging device according to Modification 2. Figure 23(A) shows an example layout on the substrate 201 of the imaging device 1. Figure 23(B) shows an example layout on the substrate 202 of the imaging device 1, and Figure 23(C) shows an example layout on the substrate 203 of the imaging device 1.

[0157] In the imaging device 1, the through-electrode 80 may be provided in a region of the substrate 202 corresponding to the pixel section 100 (pixel array), that is, in the region below the photoelectric conversion section 11 of each pixel P. The through-electrode 80 may be provided on a pixel-by-pixel basis or in multiple pixel units (i.e., every predetermined number of pixels). For example, the imaging device 1 is configured to have multiple through-electrodes 80 (through-electrode 80A, through-electrode 80B in the example shown in Figure 22) corresponding to the number of pixels (or the number of pixel signals).

[0158] In the example shown in Figure 22, the imaging device 1 has a through electrode 80A provided on the substrate 202 so as to be located within the pixel portion 100, and a through electrode 80B provided on the substrate 202 so as to be located outside the pixel portion 100. The through electrode 80A is configured, for example, as a nanoTSV and has a width smaller (narrower) than the width of the through electrode 80B in the X-axis direction (or Y-axis direction). The through electrode 80A may be provided, for example, for each pixel P or for a group of pixels P.

[0159] As schematically shown in Figure 23(C), multiple modulators 40 and multiple photodetectors 50 may be provided on the entire surface of the substrate 203, i.e., the entire substrate 203. For example, the number of modulators 40 (or photodetectors 50) on the substrate 203 may correspond to the number of signals transmitted between the processing circuit 200 and the optical circuit 300. By configuring the imaging device 1 as described above, it becomes possible to efficiently transmit signals between the substrate 202 and the substrate 203. Through electrodes 80 are also placed within the pixel section 100, allowing for a flexible layout (e.g., wiring layout).

[0160] (2-3. Variation 3) Figure 24 is a diagram illustrating an example of the configuration of an imaging device according to Modification 3. Instead of, or in addition to, the through-electrode 80, wiring 81 may be provided as in the example shown in Figure 24. The wiring 81 is provided, for example, from the side of the substrate opposite to the element formation surface to reach elements such as transistors formed on the element formation surface of the substrate. The wiring 81 can also be called back-surface wiring.

[0161] The imaging device 1 is configured to have a plurality of wirings 81, as shown in the example in Figure 24, corresponding to the number of signals transmitted between substrates 202 and 203. The wirings 81 are provided, for example, by carving into the semiconductor layer 102. In the example shown in Figure 24, the wirings 81 are formed from the surface 12S2 side to the surface 12S1 side of substrate 202 and are electrically connected to the terminals (e.g., drain or source) of the transistor on the surface 12S1 side.

[0162] In the imaging device 1 according to this modified example, connections between circuits can be made by wiring 81 (i.e., back-side wiring), making it possible to suppress the occurrence of unnecessary parasitic capacitance (e.g., wiring capacitance) in the imaging device 1. The number and arrangement of wiring 81 are not limited to the illustrated example and can be changed as appropriate.

[0163] (2-4. Modification 4) The embodiments and modifications described above illustrate examples of the configuration of the imaging device 1, but these are merely examples, and the configuration of the imaging device 1 is not limited to the examples described above. Figure 25 is a diagram illustrating an example of the configuration of the imaging device according to Modification 4. The imaging device 1 may have a stacked structure as shown in Figure 25.

[0164] In the example shown in Figure 25, the wiring layer 122 has multiple electrodes 92, and the wiring layer 121 has multiple electrodes 93. Substrates 201 and 202 are stacked such that surfaces 11S1 and 12S2 face each other, for example, by bonding between electrodes (electrodes 91, 92). That is, substrates 201 and 202 are bonded such that the surface of semiconductor layer 101 and the back surface of semiconductor layer 102 face each other.

[0165] Furthermore, substrates 202 and 203 are stacked such that surfaces 12S1 and 13S1 face each other by bonding between electrodes (electrodes 93, 94). That is, substrates 202 and 203 are bonded so that the surface of substrate 202 and the surface of substrate 203 face each other. In the imaging device 1 according to this modified example, the parasitic capacitance (wiring capacitance) added to the wiring between substrates 202 and 203 can be reduced. For example, the signal delay in the processing circuit 200 and the optical circuit 300 can be reduced, and power consumption can be reduced.

[0166] Furthermore, the imaging device 1 may be provided with the aforementioned wiring 81 (i.e., back surface wiring). In the example shown in Figure 25, the wiring 81 is provided on the substrate 202 in place of or in addition to the through-electrode 80. The wiring 81 is formed, for example, by excavating the semiconductor layer 102. As an example, the wiring 81 is formed from the surface 12S2 side to the surface 12S1 side of the substrate 202 and is electrically connected to the terminals (e.g., drain or source) of the transistor on the surface 12S1 side.

[0167] (2-5. Modification 5) Figures 26 and 27 are diagrams illustrating an example configuration of the imaging device according to Modification 5. Figure 27 schematically shows an example of the implementation of the transmission line 75. Figure 28 is a diagram illustrating an example layout of the imaging device. Figure 28(A) shows an example layout on the substrate 201 of the imaging device 1. Figure 28(B) shows an example layout on the substrate 203 of the imaging device 1, and Figure 28(C) shows an example layout on the substrate 202 of the imaging device 1.

[0168] In the example shown in Figures 26 to 28, substrates 201, 203, and 202 are provided from the side where light from the object to be measured is incident. Substrate 203 is placed between substrates 201 and 202. Substrate 203 has, for example, a semiconductor layer 103, a wiring layer 131, and a layer 132.

[0169] In the examples shown in Figures 26 and 27, layer 132 has multiple electrodes 92, and wiring layer 131 has multiple electrodes 93. Wiring layer 121 also has multiple electrodes 94. Substrate 201 and substrate 203 are laminated, for example, by bonding between electrodes (electrodes 91, 92), such that surfaces 11S1 and 13S2 face each other. That is, substrate 201 and substrate 203 are bonded so that the surface of semiconductor layer 101 and the back surface of semiconductor layer 103 face each other.

[0170] Furthermore, substrates 203 and 202 are stacked together by bonding between electrodes (electrodes 93, 94) such that surfaces 13S1 and 12S1 face each other. That is, substrates 203 and 202 are bonded together such that the surface of substrate 203 and the surface of substrate 202 face each other.

[0171] Furthermore, in the example shown in Figure 26, the through-electrode 80 is provided on the substrate 203. The through-electrode 80 is provided on the substrate 203 so as to penetrate the semiconductor layer 103. In the example shown in Figure 26, for example, the circuit element provided on the substrate 201 and the circuit element provided on the substrate 202 are electrically connected via the through-electrode 80, electrodes 91-94, etc.

[0172] The aforementioned signal line L2 (see Figures 1, 3, etc.) that transmits the pixel signal is, for example, a signal line using a through electrode 80. On the substrate 203, for example, a through electrode 80 is provided for each signal line L2. The pixel signal of the pixel P of the pixel section 100 is transmitted, for example, via electrodes 91, 92, the through electrode 80 which is part of the signal line L2, and electrodes 93, 94 to a processing circuit 200 including an AD conversion circuit 20 provided on the substrate 202.

[0173] As shown in the examples in Figures 28(B) and 28(C), the modulator 40 and the photodetector 50 may be arranged on the substrate 203, for example, directly above the I / F circuit 25 on the substrate 202. In this case, the wiring distance between the I / F circuit 25 and the modulator 40 (or photodetector 50) can be minimized. The modulator 40 (or photodetector 50) may be provided so as to overlap at least a portion of the I / F circuit 25.

[0174] The electrode region 85 has a plurality of through electrodes 80 arranged in the X-axis direction, for example, as shown in the example in Figure 28(B). The electrode region 85 is provided in the peripheral region of the optical circuit 300, as an example. In the example shown in Figure 28(B), the electrode region 85 is provided along the edge (edge ​​portion) of the substrate 203.

[0175] Furthermore, as shown in the example in Figure 26 or Figure 27, the through-electrode 80 may be provided within the region of the optical circuit 300 on the substrate 203. In this case, for example, by arranging the through-electrode 80 while avoiding the region of the island-shaped semiconductor layer 103, the parasitic capacitance added to the through-electrode 80 can be reduced.

[0176] By configuring the imaging device 1 as shown in the examples in Figures 26 to 28, the area of ​​the region where the processing circuit 200 is located can be increased. Compared to the case where through-electrodes 80 are provided on the substrate on which the processing circuit 200 is located, it is expected that parasitic capacitance can be reduced. In addition, it becomes easier to arrange through-electrodes 80 over the entire surface of the substrate.

[0177] Furthermore, substrates 203 and 202 are stacked so that the surface of substrate 203 and the surface of substrate 202 face each other. This suppresses the occurrence of large parasitic capacitance between substrates 202 and 203, thereby preventing signal delay and increased power consumption.

[0178] Furthermore, a portion of the processing circuit 200 may be placed on the substrate 203. The imaging device 1 may also have the light-shielding member 60 described above. The light-shielding member 60 (light-shielding film) is provided, for example, on layer 132 of the substrate 203 and is located between the substrate 201 and the optical circuit 300. The light-shielding member 60 may be formed on layer 132 so as to cover a portion or all of the optical circuit 300 in a plan view (i.e., when viewed in the XY plane).

[0179] Figures 29 and 30 are diagrams illustrating another configuration example of the imaging device according to Modification 5. Figure 30 schematically shows an example of the implementation of the transmission line 75. In the examples shown in Figures 29 and 30, the wiring layer 131 has a plurality of electrodes 92, and the layer 132 has a plurality of electrodes 93.

[0180] Substrates 201 and 203 are stacked, for example, by bonding between electrodes (electrodes 91, 92), such that surfaces 11S1 and 13S1 face each other. That is, substrates 201 and 203 are bonded so that the surface of semiconductor layer 101 and the surface of semiconductor layer 103 face each other.

[0181] Furthermore, substrates 203 and 202 are laminated, for example, by bonding between electrodes (electrodes 93, 94), such that surfaces 13S2 and 12S1 face each other. That is, substrates 203 and 202 are bonded so that the back surface of substrate 203 and the front surface of substrate 202 face each other.

[0182] In the example shown in Figure 29 or Figure 30, substrates 201 and 203 are stacked so that the surface of substrate 201 and the surface of substrate 203 face each other. In this case, multiple substrates 202 (for example, substrates 202a and 202b) may be stacked on the surface 13S2 side of substrate 203. The processing circuit 200 may be provided separately on substrates 202a and 202b. For example, each of substrates 202a and 202b is configured as a semiconductor chip and mounted on the imaging device 1.

[0183] In addition, in the example shown in Figure 29 or Figure 30, a part of the processing circuit 200 may be placed on the substrate 203. Furthermore, the imaging device 1 may be provided with a light-shielding member 60. In the example shown in Figure 29, the light-shielding member 60 is provided, for example, on the wiring layer 131 of the substrate 203 and is located between the substrate 201 and the optical circuit 300. The light-shielding member 60 may be formed on the wiring layer 131 so as to cover part or all of the optical circuit 300 in a plan view.

[0184] (2-6. Variation 6) Figures 31 and 32 are diagrams illustrating an example configuration of an imaging device according to Modification 6. Figure 32 schematically shows an example of the implementation of the transmission line 75. The substrate 201 may have a structure in which multiple semiconductor layers (in the example shown in Figures 31 and 32, semiconductor layer 101a and semiconductor layer 101b) are stacked.

[0185] In the examples shown in Figures 31 and 32, the substrate 201 has a semiconductor layer 101a, a layer 112, a semiconductor layer 101b, and a wiring layer 111. The semiconductor layer 101b may be composed of, for example, a silicon layer (i.e., an active layer) in an SOI substrate. The layer 112 is provided, for example, as a wiring layer or an insulating layer. The layer 112 is also referred to as the wiring layer 112.

[0186] A photoelectric conversion unit 11 for each pixel P is provided on the semiconductor layer 101a of the substrate 201. At least a part of the readout circuit 15 (see Figures 3 and 4) described above is provided on the semiconductor layer 101b. Some of the transistors of the readout circuit 15 may be placed on the semiconductor layer 101a, and some of the other transistors may be placed on the semiconductor layer 101b.

[0187] For example, the transistor TG of pixel P may be provided in semiconductor layer 101a, and at least a portion of the transistors AMP, SEL, and RST may be provided in semiconductor layer 101b. The imaging device 1 can have a structure advantageous for pixel miniaturization. In addition, a portion of the processing circuit 200 may be provided in semiconductor layer 101b and wiring layer 111.

[0188] Furthermore, at least a portion of the optical circuit 300 is provided in the semiconductor layer 101b and the wiring layer 111. For example, as shown in the example in Figure 31 or Figure 32, the modulator 40, photodetector 50, and waveguide 72 may be provided in the semiconductor layer 101b. Alternatively, for example, the light source 30 including the light-emitting element 31 may be placed on the semiconductor layer 101b.

[0189] The imaging device 1 may have a light-shielding member 65, as shown in the example in Figure 31, etc. The light-shielding member 65 is a light-shielding portion (light-shielding film) composed of a light-blocking material. The light-shielding member 65 (light-shielding film) is provided above the optical circuit 300. In the example shown in Figure 31, etc., the light-shielding member 65 is formed on the surface 11S2 side of the semiconductor layer 101a. By providing the light-shielding member 65 in the imaging device 1, it is possible to suppress the incidence of unwanted light on each element of the optical circuit 300.

[0190] The imaging device 1 may have the above-described light-shielding member 60 instead of or in addition to the light-shielding member 65. In the example shown in Figure 31 or Figure 32, the light-shielding member 60 is provided, for example, on the wiring layer 112 of the substrate 201 and is located between the semiconductor layer 101a and the optical circuit 300. The light-shielding member 60 may be formed on the wiring layer 112 so as to cover part or all of the optical circuit 300 in a plan view.

[0191] (2-7. Variation 7) Figures 33 and 34 are diagrams illustrating an example of the configuration of an imaging device according to Modification 7. The imaging device 1 may have a structure in which four or more substrates are stacked. The imaging device 1 has substrates 201 to 205, for example, as shown in the example in Figure 33 or Figure 34. The imaging device 1 may also have a substrate 206 as a support substrate.

[0192] Substrates 204 and 205 are, for example, semiconductor chips, such as processors, memory, sensors, and other integrated circuits. For instance, one of substrates 204 and 205 may be a chip composed of logic circuits, such as a DSP (Digital Signal Processor) or FPGA (Field Programmable Gate Array). The other of substrates 204 and 205 may be a chip composed of memory circuits, such as a DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory).

[0193] In the example shown in Figure 33, the substrates 204 and 205 are laminated on the substrate 203. The substrates 204 and 205 are arranged so as to be laminated on the surface 13S2 side of the substrate 203. Each of the substrates 204 and 205 is provided by lamination on the substrate 203 by bonding between electrodes (electrodes 95, 96), for example, as shown in the example in Figure 33. Note that each of the substrates 204 and 205 may have a structure in which multiple semiconductor layers are laminated.

[0194] In the imaging device 1, the circuitry on the substrate 204 (e.g., the arithmetic circuitry) is electrically connected to the optical circuitry 300 via electrodes 95, 96 and through-electrode 80, etc. The imaging device 1 is configured to enable communication between the circuitry on the substrate 204 and the circuitry of an external device, for example, by transmitting and receiving optical signals using the optical circuitry 300 and the transmission line 75.

[0195] Furthermore, in the imaging device 1, the circuits on the substrate 205 (for example, the memory circuit) are electrically connected to the optical circuit 300 via electrodes 95, 96 and through-electrode 80, etc. The imaging device 1 is configured to enable communication between the circuits on the substrate 205 and the circuits of an external device, for example, by transmitting and receiving optical signals using the optical circuit 300 and the transmission line 75.

[0196] According to the modified imaging device 1, all communication between the circuits on each substrate of the imaging device 1 (processing circuit 200, arithmetic circuit, or memory circuit, etc.) and external devices can be performed using optical signals. For example, communication between the arithmetic circuit or memory circuit and external devices can be performed at high speed, significantly improving processing capabilities.

[0197] Figures 35 and 36 illustrate another configuration example of the imaging device according to Modification 7. The imaging device 1 may have a configuration in which a plurality of substrates are individually stacked on a substrate 203 on which the optical circuit 300 is provided. For example, a substrate 202 on which substrate 201 is stacked, a substrate 204, and a substrate 205 are arranged in different regions on one side of the substrate 203.

[0198] As shown in the example in Figure 35 or Figure 36, the size of substrate 203 (e.g., area in the XY plane) is larger than the size of each of substrates 201, 202, 204, and 205 (e.g., area in the XY plane). In the example shown in Figure 35, substrates 201 and 202 are stacked on region R1 of substrate 203.

[0199] Furthermore, substrate 204 (e.g., arithmetic circuit) is stacked on region R2 of substrate 203. Substrate 205 (e.g., memory circuit) is stacked on region R3 of substrate 203. Each of substrates 202, 204, and 205 is joined to substrate 203, for example, by electrode-to-electrode bonding. Note that four or more, or five or more, substrates may be arranged on substrate 203.

[0200] By configuring the imaging device 1 as shown in the example in Figure 35, the substrate 203 can be used as an interposer (i.e., an interposer substrate), and for example, substrates 202, 204, and 205 can be placed far apart from each other. This makes it possible to mitigate the adverse effects of heat generation on each substrate on the imaging device 1.

[0201] Figures 37 and 38 are diagrams illustrating another configuration example of the imaging device according to Modification 7. The imaging device 1 may have a substrate 207 as an interposer (interposer substrate). The substrate 207 has one or more waveguides 72 (waveguides 72a to 72c in Figure 37, etc.) as shown in the example in Figure 37 or Figure 38, and is configured as an optical interposer substrate.

[0202] In the imaging device 1, for example, substrate 203, which has substrates 201 and 202 stacked on it, substrate 204, and substrate 205 are arranged separately on substrate 207. Substrates 204 and 205 have an optical circuit 320, as schematically shown in Figure 37. The optical circuit 320 is configured to include, for example, a circuit similar to that of optical circuit 300 (modulator 40, photodetector 50, amplifier circuit, etc.). Waveguides 72a to 72c are configured to transmit optical signals from optical circuit 300 (for example, optical signals based on pixel signals), optical signals from optical circuit 320, etc.

[0203] In the example shown in Figure 37, the substrate 207 is provided with a light source 30 including a light-emitting element 31 and a waveguide 71. The output light from the light source 30 is transmitted via the waveguide 71 of the substrate 207 to, for example, a modulator 40 on the substrate 203. The output light from the light source 30 can also be transmitted via the waveguide to optical circuits 320 on the substrate 204 and optical circuits 320 on the substrate 205. The light source 30 may be mounted on the substrate 207, or it may be provided on the substrate 203 or another substrate.

[0204] The optical circuit 300 on substrate 203, the optical circuit 320 on substrate 204, and the optical circuit 320 on substrate 205 are optically connected to each other, for example, by waveguides 72a to 72c. For example, the circuits provided on substrates 203 to 205 are optically connected (coupled) to each other by evanescent coupling, antennas, three-dimensional waveguides, etc.

[0205] In the imaging device 1, for example, the optical circuit 300 on substrate 203 communicates with the optical circuit 320 on substrate 204 or the optical circuit 320 on substrate 205 via waveguide 72a. Also, the optical circuit 320 on substrate 204 communicates with the optical circuit 320 on substrate 205 via waveguide 72b.

[0206] As described above, the imaging device 1 communicates between the circuits on substrate 202 (e.g., processing circuit 200), substrate 204 (e.g., arithmetic circuit), and substrate 205 (e.g., memory circuit) by transmitting and receiving optical signals using optical circuits 300, 320 and waveguides 72a to 72c. Furthermore, the imaging device 1 can communicate between the circuits on each substrate and the circuits of an external device by transmitting and receiving optical signals via waveguide 72c and transmission line 75.

[0207] As described above, the imaging device 1 may have a configuration in which multiple substrates are connected via a substrate 207 acting as an optical interposer substrate (i.e., a chiplet configuration). This makes it possible to realize an imaging device (optical detection device) that enables suitable communication. Furthermore, for example, substrates 202, 204, and 205 can be arranged far apart from each other, thereby suppressing adverse effects on the imaging device 1 due to heat generated by each substrate.

[0208] <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 39 shows a schematic configuration of the electronic device 1000.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] 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.

[0214] The imaging device 1 can convert the pixel signals obtained as electrical signals into optical signals and supply the converted optical pixel signals to the DSP circuit 1002. The imaging device 1 may also output the converted optical pixel signals to the bus line 1008, as shown in the example in Figure 40. The imaging device 1 can also broadcast signals to multiple circuits, including the DSP circuit 1002.

[0215] <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.

[0216] Figure 41 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.

[0217] The vehicle control system 12000 comprises multiple electronic control units connected via a communication network 12001. In the example shown in Figure 41, 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.

[0218] 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.

[0219] 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.

[0220] 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.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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 41, 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.

[0227] Figure 42 shows an example of the installation position of the imaging unit 12031.

[0228] In Figure 42, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0229] 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.

[0230] Figure 42 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.

[0231] 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.

[0232] 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.

[0233] 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.

[0234] 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.

[0235] 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 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.

[0236] The imaging unit 12031 to which the above-described imaging device 1 is applied can convert an electrical signal corresponding to the amount of light received into an optical signal and output that optical signal. The imaging unit 12031 (for example, imaging units 12101 to 12105) can output an optical signal as image information, or it can output an optical signal as distance measurement information.

[0237] The imaging unit 12031 is connected to the drive system control unit 12010, the body system control unit 12020, the external information detection unit 12030, the internal information detection unit 12040, and the integrated control unit 12050 via the communication network 12001, as shown in the example in Figure 43.

[0238] The microcomputer 12051 may receive signals from the imaging unit 12031 without going through the external information detection unit 12030 and detect information outside the vehicle. For example, the microcomputer 12051 may perform object detection processing or distance detection processing, such as detecting people, cars, obstacles, signs, or characters on the road surface, based on the signals received from the imaging unit 12031.

[0239] (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.

[0240] Figure 44 is a diagram showing an example of a schematic configuration of an endoscopic surgical system to which the technology described herein (the technology) may be applied.

[0241] Figure 44 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.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] 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.

[0246] 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.

[0247] 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.

[0248] 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.

[0249] 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.

[0250] The light source device 11203 that supplies irradiation light for photographing the surgical site with the endoscope 11100 can be composed of, for example, a white light source composed of an LED, a laser light source, or a combination thereof. When the white light source is composed of a combination of RGB laser light sources, since the output intensity and output timing of each color (each wavelength) can be controlled with high precision, the white balance of the captured image can be adjusted in the light source device 11203. Also, in this case, the laser light from each of the RGB laser light sources is irradiated to the observation target in a time-sharing manner, and by controlling the driving of the imaging element of the camera head 11102 in synchronization with the irradiation timing, it is also possible to capture images corresponding to each of RGB in a time-sharing manner. According to this method, a color image can be obtained without providing a color filter on the imaging element.

[0251] Further, the driving of the light source device 11203 may be controlled so that the intensity of the output light is changed every predetermined time. By controlling the driving of the imaging element of the camera head 11102 in synchronization with the timing of the change in the intensity of the light and acquiring images in a time-sharing manner and synthesizing the images, a so-called high dynamic range image without black crush and white clip can be generated.

[0252] In addition, 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, a narrow-band light is irradiated as compared with the irradiation light (i.e., white light) during normal observation, so as to perform so-called narrow-band imaging that captures a predetermined tissue such as blood vessels in the mucosal surface layer with high contrast. Alternatively, in special light observation, fluorescence observation may be performed to obtain an image by fluorescence generated by irradiating excitation light. In fluorescence observation, excitation light may be irradiated on body tissue to observe fluorescence from the body tissue (autofluorescence observation), or a reagent such as indocyanine green (ICG) may be locally injected into the body tissue and excitation light corresponding to the fluorescence wavelength of the reagent may be irradiated on the body tissue to obtain a fluorescence image. The light source device 11203 can be configured to supply such narrow-band light and / or excitation light corresponding to special light observation.

[0253] FIG. 45 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG. 44.

[0254] 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 communicably connected to each other by a transmission cable 11400.

[0255] The lens unit 1140 is an optical system provided at a connection portion with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is configured by combining a plurality of lenses including a zoom lens and a focus lens.

[0256] 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.

[0257] 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.

[0258] 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.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] 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.

[0264] 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 via telecommunications, optical communications, etc.

[0265] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102.

[0266] 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.

[0267] 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.

[0268] 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.

[0269] 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.

[0270] 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.

[0271] The imaging unit 11402 to which the imaging device 1 is applied may convert an electrical signal corresponding to observation light into an optical signal and output the optical signal. The imaging unit 11402 may be configured to include the communication unit 11404 as in the example shown in FIG. 46. The imaging device 1, the optical circuit 300, etc. can be applied to, for example, the imaging unit 11402 and the communication unit 11404. The imaging unit 11402 can transmit and receive image signals and control signals by optical communication, electrical communication, etc.

[0272] The present disclosure has been described by way of embodiments, modifications, application examples, and usage examples. However, the present technology is not limited to the above embodiments, and various modifications are possible. For example, although the above modifications have been described as modifications of the above embodiments, the configurations of each modification can be appropriately combined.

[0273] In the above embodiments and the like, the imaging device has been illustrated and described. However, the light detection device of the present disclosure may be, for example, any device that receives incident light and converts the light into electric charges. The output signal may be a signal of image information or a signal of distance measurement information. The light detection device (imaging device) can be applied to an image sensor, a distance measurement sensor, etc. Note that the present disclosure is not limited to a back-illuminated image sensor and can also be applied to a front-illuminated image sensor.

[0274] The light detection device according to the present disclosure can also be applied as a distance measurement sensor capable of distance measurement by the TOF (Time Of Flight) method. The light detection device (imaging device) can also be applied as a sensor capable of detecting events, for example, an event-driven sensor (referred to as EVS (Event Vision Sensor), EDS (Event Driven Sensor), DVS (Dynamic Vision Sensor), etc.).

[0275] One embodiment of the photodetector in this disclosure comprises a first substrate having a photoelectric conversion element, a second substrate laminated with the first substrate and having at least a portion of a processing circuit capable of performing signal processing on a first signal generated based on the charge converted by the photoelectric conversion element, and an optical circuit capable of outputting a first optical signal based on the first signal. This makes it possible to realize a photodetector that enables suitable communication.

[0276] One embodiment of the optical detection system of this disclosure comprises an optical detection device and an external device. The optical detection device comprises a first substrate having a photoelectric conversion element, a second substrate laminated with the first substrate and having at least a portion of a processing circuit capable of performing signal processing on a first signal generated based on the charge converted by the photoelectric conversion element, and an optical circuit capable of transmitting a first optical signal based on the first signal to the external device. This makes it possible to realize an optical detection system that enables suitable communication.

[0277] 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) A first substrate having a photoelectric conversion element that converts light into photoelectric energy, A second substrate laminated with the first substrate has at least a portion of a processing circuit capable of performing signal processing on a first signal generated based on the charge converted by the photoelectric conversion element, An optical circuit capable of outputting a first optical signal based on the first signal and A light detection device equipped with the following features. (2) The optical circuit is provided so as to be stacked above or below the second substrate. The light detection device described in (1) above. (3) The photoelectric conversion element is included, and the pixel is capable of outputting the first signal based on the charge converted by the photoelectric conversion element. The light detection device described in (1) or (2) above. (4) The processing circuit includes an AD conversion circuit capable of converting the first signal into a digital signal, and is capable of performing signal processing on the first signal converted into a digital signal. The optical circuit is capable of converting the first signal output from the processing circuit into the first optical signal. The light detection device described in any one of (1) to (3) above. (5) The optical circuit has a modulator capable of outputting the first optical signal modulated based on the first signal. The light detection device described in any one of (1) to (4) above. (6) The device comprises a third substrate stacked with the second substrate, At least a portion of the optical circuit is provided on the third substrate. The light detection device described in any one of (1) to (5) above. (7) The second substrate further comprises a first through-electrode, The first substrate and the second substrate are stacked such that the surface on which the elements of the first substrate are formed and the surface on which the elements of the second substrate are formed face each other. The second substrate and the third substrate are stacked such that the side of the second substrate opposite to the side on which the elements are formed faces the side of the third substrate on which the elements are formed. The light detection device described in (6) above. (8) The second substrate further comprises a first wiring, The first substrate and the second substrate are stacked such that the surface on which the elements of the first substrate are formed and the surface on which the elements of the second substrate are formed face each other. The second substrate and the third substrate are stacked such that the side of the second substrate opposite to the side on which the elements are formed faces the side of the third substrate on which the elements are formed. The first wiring is provided so as to reach the elements on the second substrate from the side opposite to the side on which the elements on the second substrate are formed. The light detection device described in (6) above. (9) The second substrate further comprises a first through-electrode, The first substrate and the second substrate are stacked such that the surface on which the elements of the first substrate are formed and the surface on which the elements of the second substrate are formed are opposite to each other. The second substrate and the third substrate are stacked such that the surface on which the elements of the second substrate are formed and the surface on which the elements of the third substrate are formed face each other. The light detection device described in (6) above. (10) One or more fourth substrates stacked with the third substrate, The second through electrode provided on the third substrate and Furthermore, it is equipped with The light detection device described in any one of (6) to (9) above. (11) The present invention further comprises one or more fourth substrates stacked with the third substrate, The size of the third substrate is larger than the size of each of the first substrate, the second substrate and one or more of the fourth substrates. The first substrate and the second substrate are stacked on a portion of the third substrate. One or more of the fourth substrates are stacked on other portions of the third substrate. The light detection device described in any one of (1) to (10) above. (12) The fifth substrate further comprises a waveguide capable of transmitting the first optical signal from the optical circuit and is laminated with the third substrate. The light detection device described in any one of (1) to (10) above. (13) At least a portion of the optical circuit is provided on the first substrate. The light detection device described in any one of (1) to (12) above. (14) The first substrate has a first layer on which the photoelectric conversion element is provided, and a second layer provided stacked with the first layer. At least a portion of the optical circuit is provided in the second layer. The light detection device described in any one of (1) to (13) above. (15) The optical circuit is further provided with a light-shielding member that covers the optical circuit above it. The light detection device described in any one of (1) to (14) above. (16) A third substrate having the aforementioned optical circuit and stacked with the second substrate, A light-shielding member provided between the second substrate and the optical circuit and Furthermore, it is equipped with The light detection device described in any one of (1) to (15) above. (17) The third substrate has a wiring layer on which the light-shielding member is provided, The light-shielding member is provided in multiple layers of the wiring layer. The light detection device described in (16) above. (18) The optical circuit has a light source, The optical circuit is capable of converting the first signal into the first optical signal based on the output light of the light source. The light detection device described in any one of (1) to (17) above. (19) The optical circuit has a photodetector capable of receiving a second optical signal from an external source. The light detection device described in any one of (1) to (18) above. (20) Light detection device and External devices and Equipped with, The aforementioned light detection device is A first substrate having a photoelectric conversion element that converts light into photoelectric energy, A second substrate laminated with the first substrate has at least a portion of a processing circuit capable of performing signal processing on a first signal generated based on the charge converted by the photoelectric conversion element, An optical circuit capable of transmitting a first optical signal based on the first signal to the external device and has Light detection system. (twenty one) The system further comprises a transmission path connected between the aforementioned photodetector and the aforementioned external device. The light detection system described in (20) above. (twenty two) The optical circuit is capable of transmitting the first optical signal to the external device via the transmission path. The light detection system described in (21) above. [Explanation of Symbols]

[0278] 1...Imaging device, 10...Photodetection system, 11...Photoelectric conversion unit, 30...Light source, 40...Modulator, 50...Photodetector, 200...Processing circuit, 300...Optical circuit.

Claims

1. A first substrate having a photoelectric conversion element that converts light into photoelectric energy, A second substrate laminated with the first substrate has at least a portion of a processing circuit capable of performing signal processing on a first signal generated based on the charge converted by the photoelectric conversion element, An optical circuit capable of outputting a first optical signal based on the first signal and A light detection device equipped with the following features.

2. The optical circuit is provided so as to be stacked above or below the second substrate. The light detection device according to claim 1.

3. The photoelectric conversion element is included, and the pixel is capable of outputting the first signal based on the charge converted by the photoelectric conversion element. The light detection device according to claim 1.

4. The processing circuit has an AD conversion circuit capable of converting the first signal into a digital signal, and is capable of performing signal processing on the first signal converted into a digital signal. The optical circuit is capable of converting the first signal output from the processing circuit into a first optical signal. The light detection device according to claim 1.

5. The optical circuit has a modulator capable of outputting the first optical signal modulated based on the first signal. The light detection device according to claim 1.

6. The present invention comprises a third substrate stacked with the second substrate, At least a portion of the optical circuit is provided on the third substrate. The light detection device according to claim 1.

7. The second substrate further comprises a first through-electrode, The first substrate and the second substrate are stacked such that the surface on which the elements of the first substrate are formed and the surface on which the elements of the second substrate are formed face each other. The second substrate and the third substrate are stacked such that the side of the second substrate opposite to the side on which the elements are formed faces the side of the third substrate on which the elements are formed. The light detection device according to claim 6.

8. The second substrate further comprises a first wiring, The first substrate and the second substrate are stacked such that the surface on which the elements of the first substrate are formed and the surface on which the elements of the second substrate are formed face each other. The second substrate and the third substrate are stacked such that the side of the second substrate opposite to the side on which the elements are formed faces the side of the third substrate on which the elements are formed. The first wiring is provided so as to reach the elements on the second substrate from the side opposite to the side on which the elements on the second substrate are formed. The light detection device according to claim 6.

9. The second substrate further comprises a first through-electrode, The first substrate and the second substrate are stacked such that the surface on which the elements of the first substrate are formed and the surface on which the elements of the second substrate are formed are opposite to each other. The second substrate and the third substrate are stacked such that the surface on which the elements of the second substrate are formed and the surface on which the elements of the third substrate are formed face each other. The light detection device according to claim 6.

10. One or more fourth substrates stacked with the third substrate, The second through electrode provided on the third substrate and Furthermore, it is equipped with The light detection device according to claim 6.

11. The present invention further comprises one or more fourth substrates laminated with the third substrate, The size of the third substrate is larger than the size of each of the first substrate, the second substrate and one or more of the fourth substrates. The first substrate and the second substrate are stacked on a portion of the third substrate. One or more of the fourth substrates are stacked on other portions of the third substrate. The light detection device according to claim 6.

12. The fifth substrate further comprises a waveguide capable of transmitting the first optical signal from the optical circuit and is laminated with the third substrate. The light detection device according to claim 6.

13. At least a portion of the optical circuit is provided on the first substrate. The light detection device according to claim 1.

14. The first substrate has a first layer on which the photoelectric conversion element is provided, and a second layer provided stacked with the first layer. At least a portion of the optical circuit is provided in the second layer. The light detection device according to claim 1.

15. The optical circuit is further provided with a light-shielding member that covers the optical circuit above it. The light detection device according to claim 1.

16. A third substrate having the aforementioned optical circuit and laminated with the second substrate, A light-shielding member provided between the second substrate and the optical circuit and Furthermore, it is equipped with The light detection device according to claim 1.

17. The third substrate has a wiring layer on which the light-shielding member is provided, The light-shielding member is provided in multiple layers of the wiring layer. The light detection device according to claim 16.

18. The optical circuit has a light source, The optical circuit is capable of converting the first signal into a first optical signal based on the output light of the light source. The light detection device according to claim 1.

19. The optical circuit has a photodetector capable of receiving a second optical signal from an external source. The light detection device according to claim 1.

20. Light detection device and External devices and Equipped with, The aforementioned light detection device is A first substrate having a photoelectric conversion element that converts light into photoelectric energy, A second substrate laminated with the first substrate has at least a portion of a processing circuit capable of performing signal processing on a first signal generated based on the charge converted by the photoelectric conversion element, An optical circuit capable of transmitting a first optical signal based on the first signal to the external device and has Light detection system.

Images