Light detection device

Abstract

A light detection device according to one embodiment of the present disclosure comprises: a semiconductor substrate that has a first surface where light is incident, and a second surface located on the opposite side from the first surface, a plurality of pixels being arranged in a two-dimensional array on said semiconductor substrate, and said plurality of pixels including a first pixel that detects light in a first wavelength band among the incident light; and a light guide unit that is positioned on the first surface side of the semiconductor substrate and includes a first wavelength condensing region for condensing, on the first pixel, light in the first wavelength band among the incident light. The light guide unit has a first condensing point where the light in the first wavelength band is condensed substantially in the center of the first pixel. The first wavelength condensing region has an area that is greater than the area of the first pixel, and extends asymmetrically from the first condensing point.

Description

Light detection device

[0001] This disclosure relates to a photodetector.

[0002] For example, Patent Document 1 discloses a photodetector in which an optical control region is stacked on the light incident side of a photoelectric conversion region having multiple pixels to control the direction of light propagation to the photoelectric conversion region. The optical control region has a pixel control region having a microstructure for each of the multiple pixels, and the pixel control region controls the direction of light propagation of the amount of light within the aperture range corresponding to the image height.

[0003] Japanese Patent Publication No. 2023-152552

[0004] By the way, in light detection devices where pixel miniaturization has progressed, there is a need to improve the image quality degradation that occurs with miniaturization.

[0005] It is desirable to provide a light detection device capable of improving image quality.

[0006] An optical detection device as one embodiment of the present disclosure comprises a semiconductor substrate having a first surface to which light is incident and a second surface located opposite to the first surface, and a plurality of pixels including a first pixel that detects light in a first wavelength band from the incident light arranged in a two-dimensional array, and a light guide portion arranged on the first surface side of the semiconductor substrate and including a first wavelength focusing region that focuses light in the first wavelength band from the incident light onto the first pixel, wherein the light guide portion has a first focusing point where light in the first wavelength band is focused approximately at the center of the first pixel, and the first wavelength focusing region has an area larger than the area of ​​the first pixel and extends asymmetrically from the first focusing point.

[0007] In one embodiment of the present disclosure, a light guide is provided on the first surface side of a semiconductor substrate, which is the light incident surface, where a plurality of pixels, including a first pixel that detects light in a first wavelength band, are arranged in a two-dimensional array. The light guide includes a first wavelength focusing region that focuses light in the first wavelength band from the incident light onto the first pixel, and has a first focusing point where light in the first wavelength band is focused approximately at the center of the first pixel. The first wavelength focusing region has an area larger than the area of ​​the first pixel and extends asymmetrically from the first focusing point. As a result, in addition to light in the first wavelength band incident from above the first pixel, light in the first wavelength band incident on pixels surrounding the first pixel is also focused onto the first pixel.

[0008] Figure 1 is a block diagram showing an example of the schematic configuration of a photodetector according to one embodiment of the present disclosure. Figure 2 is a schematic plan view showing an example of the pixel section of the photodetector shown in Figure 1. Figure 3 is a diagram showing an example of the circuit configuration of a unit pixel of the photodetector shown in Figure 1. Figure 4 is a schematic cross-sectional view showing an example of the configuration of the photodetector shown in Figure 1. Figure 5 is a schematic diagram showing an example of the plan configuration of the photodetector shown in Figure 1. Figure 6 is a conceptual diagram illustrating the spectroscopy of the light guide section shown in Figure 4. Figure 7 is a conceptual diagram illustrating the spectroscopy of a light guide section used in a general photodetector. Figure 8 is a diagram showing the phase profile of light that has passed through the light guide section shown in Figure 4. Figure 9 is a diagram showing an example of the focusing region of a light guide section used in a general photodetector. Figure 10 is a diagram showing another example of the focusing region of a light guide section used in a general photodetector. Figure 11 is a diagram illustrating the focusing region and focusing point of light with a wavelength of 600 nm in the light guide section shown in Figure 4. Figure 12 is a diagram illustrating the focusing region and focusing point of light with a wavelength of 500 nm in the light guide section shown in Figure 4. Figure 13 is a diagram illustrating the light-gathering region and focal point of 400 nm light in the light guide section shown in Figure 4. Figure 14 is a diagram illustrating an example of readout when an optical detector having the pixel array shown in Figure 13 is used for addition. Figure 15 is a diagram illustrating an example of readout when an optical detector having a Bayer array is used for addition. Figure 16 is a diagram illustrating another example of readout when an optical detector having a Bayer array is used for addition. Figure 17 is a diagram illustrating an example of readout when an optical detector having the optical detector shown in Figure 1 is used for addition. Figure 18 is a diagram showing the light-gathering region and focal point of 600 nm light in the light guide section according to Modification 1 of this disclosure. Figure 19 is a diagram showing the light-gathering region and focal point of 500 nm light in the light guide section according to Modification 1 of this disclosure. Figure 20 is a diagram showing the light-gathering region and focal point of 400 nm light in the light guide section according to Modification 1 of this disclosure. Figure 21 shows the light-gathering region and focal point of light with a wavelength of 600 nm in the light guide portion according to Modification 2 of this disclosure. Figure 22 shows the light-gathering region and focal point of light with a wavelength of 500 nm in the light guide portion according to Modification 2 of this disclosure. Figure 23 shows the light-gathering region and focal point of light with a wavelength of 400 nm in the light guide portion according to Modification 2 of this disclosure.Figure 24 shows the light-gathering region and focal point of light with a wavelength of 600 nm in the light guide portion according to Modification 3 of this disclosure. Figure 25 shows the light-gathering region and focal point of light with a wavelength of 500 nm in the light guide portion according to Modification 3 of this disclosure. Figure 26 shows the light-gathering region and focal point of light with a wavelength of 400 nm in the light guide portion according to Modification 3 of this disclosure. Figure 27 shows the light-gathering region and focal point of light with a wavelength of 600 nm in the light guide portion according to Modification 4 of this disclosure. Figure 28 shows the light-gathering region and focal point of light with a wavelength of 500 nm in the light guide portion according to Modification 4 of this disclosure. Figure 29 shows the light-gathering region and focal point of light with a wavelength of 400 nm in the light guide portion according to Modification 4 of this disclosure. Figure 30 shows the light-gathering region and focal point of light with a wavelength of 1300 nm in the light guide portion according to Modification 4 of this disclosure. Figure 31 is a diagram showing the light-gathering region and focal point of 600 nm light in the light guide unit according to Modification 5 of this disclosure. Figure 32 is a diagram showing the light-gathering region and focal point of 500 nm light in the light guide unit according to Modification 5 of this disclosure. Figure 33 is a diagram showing the light-gathering region and focal point of 400 nm light in the light guide unit according to Modification 5 of this disclosure. Figure 34 is a functional block diagram showing an example of an electronic device (camera) using the photodetector shown in Figure 1. Figure 35A is a schematic diagram showing an example of the overall configuration of a photodetection system using the photodetector shown in Figure 1. Figure 35B is a diagram showing an example of the circuit configuration of the photodetection system shown in Figure 35A. Figure 36 is a diagram showing an example of the schematic configuration of an endoscopic surgery system. Figure 37 is a block diagram showing an example of the functional configuration of a camera head and a CCU. Figure 38 is a block diagram showing an example of the schematic configuration of a vehicle control system. Figure 39 is an explanatory diagram showing an example of the installation position of an external information detection unit and an imaging unit.

[0009] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following embodiments. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc., of each component shown in each figure. The order of description is as follows: 1. Embodiment (An example of a light detection device that includes a first wavelength focusing region that focuses light of the first wavelength band onto a first pixel, and has a first focusing point where light of the first wavelength band is focused approximately at the center of the first pixel, the first wavelength focusing region having an area larger than the area of ​​the first pixel, and a light guide extending asymmetrically from the first focusing point) 2. Modifications 2-1. Modification 1 (Another example of the configuration of the light guide) 2-2. Modification 2 (Another example of the configuration of the light guide) 2-3. Modification 3 (Another example of the configuration of the light guide) 2-4. Modification 4 (Another example of the configuration of the light guide) 2-5. Modification 5 (Another example of the configuration of the light guide) 3. Application Example 4. Application Example

[0010] <1. Embodiments>

[0011] [Outline Configuration of the Photodetector] Figure 1 is a block diagram showing an example of the schematic configuration of the photodetector (photodetector 1) of the present disclosure. Figure 2 schematically shows an example of the configuration of the pixel array section 100 and its surroundings of the photodetector 1 shown in Figure 2. The photodetector 1 is applicable to CMOS (Complementary Metal Oxide Semiconductor) image sensors used in electronic devices such as digital still cameras and video cameras, and has an effective pixel area (pixel array section 100) in which a plurality of pixels are arranged in a matrix in two dimensions as an imaging area. The photodetector 1 is, for example, a so-called back-illuminated photodetector in this CMOS image sensor.

[0012] The light detection device 1 captures incident light (image light) from a subject via an optical lens system (for example, optical system 1001, see Figure 34), converts the amount of light of the incident light formed on the imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs it as a pixel signal. The light detection device 1 has a pixel array section 100 as an imaging area on a semiconductor substrate 11, and a peripheral section around this pixel array section 100. In the peripheral section, for example, an optical black (OPB) area that outputs a background signal is provided so as to surround the pixel array section 100. In the OPB area, for example, a plurality of unit pixels P are arranged in a matrix in a two-dimensional manner, similar to the pixel array section 100, and a photodiode (PD) is provided for each unit pixel P. In the peripheral section, for example, a pixel control section 111, a signal processing section 112, a control section 113, and a processing section 114 are provided. The light detection device 1 is also provided with, for example, a plurality of control lines Lread and a plurality of signal lines VSL.

[0013] In the pixel array section 100, for example, multiple unit pixels P are arranged in a matrix in a two-dimensional manner. For example, control lines Lread (specifically row selection lines and reset control lines) are wired to each pixel row of unit pixels P, and signal lines VSL are wired to each pixel column.

[0014] The control line Lread is a signal line capable of transmitting signals to control a unit pixel P, and is connected to the pixel control unit 111 and the unit pixel P of the pixel array unit 100. The control line Lread is configured to transmit control signals for reading signals from the unit pixel P. The control line Lread can also be called a drive line (pixel drive line) that transmits signals to drive the unit pixel P.

[0015] A signal line VSL is a signal line capable of transmitting signals from a unit pixel P, and is connected to the unit pixel P of the pixel array section 100 and the signal processing section 112. In the pixel array section 100, for example, one or more signal lines VSL are wired to each pixel row, which is composed of multiple unit pixels P arranged vertically (in the column direction). The signal lines VSL are configured to transmit signals output from the unit pixels P. In the photodetector 1, multiple signal lines VSL may be provided for a single pixel row.

[0016] The pixel control unit 111 is configured to control each unit pixel P of the pixel array unit 100. The pixel control unit 111 is a control circuit and is composed of multiple circuits, such as a buffer, a shift register, and an address decoder. The pixel control unit 111 generates a signal for controlling the unit pixel P and outputs it to each unit pixel P of the pixel array unit 100 via the control line Lread. The pixel control unit 111 is controlled by the control unit 113 and controls the unit pixels P of the pixel array unit 100.

[0017] The pixel control unit 111 generates signals for controlling the unit pixels P, such as signals for controlling the transfer transistor of the unit pixel P, signals for controlling the selection transistor, and signals for controlling the reset transistor, and supplies these signals to each unit pixel P via the control line Lread. The pixel control unit 111 can control the reading of pixel signals from each unit pixel P. The pixel control unit 111 can also be described as a pixel drive unit configured to drive each unit pixel P. The pixel control unit 111 and the control unit 113 together can also be referred to as the pixel control unit.

[0018] The signal processing unit 112 is configured to perform processing of the input pixel signal. The signal processing unit 112 is a signal processing circuit and includes, for example, a load circuit, an analog-to-digital (AD) conversion circuit, and a horizontal selection switch. The load circuit is, for example, composed of a current source capable of supplying current to the amplification transistor of a unit pixel P. The load circuit, together with the amplification transistor of the unit pixel P, constitutes a source follower circuit.

[0019] The signal processing unit 112 may have an amplification circuit configured to amplify the signal read from the unit pixel P via the signal line VSL. Load circuits, amplification circuits, and AD conversion circuits, etc., are provided, for example, for each of the multiple signal lines VSL. Load circuits, amplification circuits, and AD conversion circuits, etc., may be provided for each pixel row of the pixel array unit 100.

[0020] The signals output from each unit pixel P selected and scanned by the pixel control unit 111 are input to the signal processing unit 112 via the signal line VSL. The signal processing unit 112 can perform signal processing such as AD conversion and correlated double sampling (CDS) of the unit pixel P signals. The signals of each unit pixel P transmitted through each of the signal lines VSL are processed by the signal processing unit 112 and output to the processing unit 114.

[0021] The processing unit 114 is configured to perform signal processing on the input signal. The processing unit 114 is a processing circuit and is composed of, for example, a circuit that performs various signal processing on the pixel signal. The processing unit 114 may also include a processor and memory. The processing unit 114 performs signal processing on the pixel signal input from the signal processing unit 112 and outputs the processed pixel signal. The processing unit 114 can perform various signal processing, such as noise reduction processing and gradation correction processing.

[0022] The control unit 113 is configured to control each part of the light detection device 1. The control unit 113 receives data such as a clock and operating mode commands from an external source, and can output data such as internal information of the light detection device 1. The control unit 113 is a control circuit and, for example, has a timing generator configured to generate various timing signals. Based on the various timing signals (pulse signals, clock signals, etc.) generated by the timing generator, the control unit 113 performs drive control of the pixel control unit 111 and the signal processing unit 112, etc.

[0023] The pixel array section 100, the pixel control unit 111, and the signal processing unit 112 may be provided on a single substrate. Alternatively, the pixel control unit 111, the signal processing unit 112, the control unit 113, and the processing unit 114 may be provided on a single semiconductor substrate, or they may be provided on multiple semiconductor substrates. The photodetector 1 may have a laminated structure formed by stacking multiple substrates. Some or all of the signal processing unit 112, the control unit 113, and the processing unit 114 may be integrally configured.

[0024] The pixel array unit 100 is an area that photoelectrically converts a subject image formed by an imaging lens in a photodiode (PD) provided for each unit pixel P to generate a signal for image generation. A first dummy pixel area for generating a pixel signal for assisting image generation may be provided at the periphery of the effective pixel area. Further, a second dummy pixel area that does not generate a pixel signal may be provided outside the first dummy pixel area.

[0025] [Circuit configuration of unit pixel] FIG. 3 shows an example of the circuit configuration of the unit pixel P of the photodetection device 1 shown in FIG. 1. The unit pixel P has, for example, a photoelectric conversion unit 12 and a readout circuit 31. The photoelectric conversion unit 12 is configured to receive light and generate a signal. The readout circuit 31 is configured to output a signal based on the charge that has been photoelectrically converted. The readout circuit 31 can read out a pixel signal based on the charge photoelectrically converted by the photoelectric conversion unit 12.

[0026] The photoelectric conversion unit 12 is a so-called light-receiving element and is configured to be able to generate charge by photoelectric conversion. The photoelectric conversion unit 12 is, for example, a photodiode (PD) that converts incident light into charge. The photoelectric conversion unit 12 can perform photoelectric conversion to generate charge corresponding to the amount of light received.

[0027] As an example, the readout circuit 31 has a transfer transistor TRG, a floating diffusion FD, an amplification transistor AMP, a selection transistor SEL, and a reset transistor RST. The transfer transistor TRG, the amplification transistor AMP, the selection transistor SEL, and the reset transistor RST are each MOS transistors (MOSFETs) having gate, source, and drain terminals.

[0028] For example, the transfer transistor TRG, the amplification transistor AMP, the selection transistor SEL, and the reset transistor RST are each constituted by an NMOS transistor. Note that each transistor constituting the readout circuit 31 may be constituted by a PMOS transistor.

[0029] The transfer transistor TRG is configured to transfer the charge photoelectrically converted in the photoelectric conversion unit 12 to the floating diffusion FD. The transfer transistor TRG is controlled by the signal STRG and electrically connects or disconnects the photoelectric conversion unit 12 and the floating diffusion FD. The transfer transistor TRG can transfer the charge photoelectrically converted and stored in the photoelectric conversion unit 12 to the floating diffusion FD.

[0030] The floating diffusion FD is a storage unit and is configured to store the transferred charge. The floating diffusion FD can store the charge converted photoelectrically by the photoelectric conversion unit 12. The floating diffusion FD can also be described as a storage unit capable of holding the transferred charge. The floating diffusion FD stores the transferred charge and converts it into a voltage corresponding to the capacitance of the floating diffusion FD.

[0031] The amplification transistor AMP is configured to generate and output a signal based on the charge accumulated in the floating diffusion FD. The amplification transistor AMP can generate and output a signal based on the charge converted by the photoelectric conversion unit 12.

[0032] The gate of the amplification transistor AMP is electrically connected to a floating diffusion diode (FD), and the voltage converted by the floating diffusion diode is input to it. The drain of the amplification transistor AMP is connected to a power line, for example, to which the power supply voltage VDD is supplied.

[0033] The source of the amplification transistor AMP is connected to the signal line VSL via the selection transistor SEL. The amplification transistor AMP is configured to generate a signal based on the charge stored in the floating diffusion FD, i.e., a signal based on the voltage of the floating diffusion FD, and output it to the signal line VSL.

[0034] The selection transistor SEL is configured to control the output of the pixel signal. The selection transistor SEL is electrically connected in series with, for example, the amplification transistor AMP. The selection transistor SEL is controlled by the signal SSEL and is configured to output the signal from the amplification transistor AMP to the signal line VSL. The selection transistor SEL can control the timing of the pixel signal output.

[0035] The selection transistor SEL is configured to output a signal based on the charge converted by the photoelectric conversion unit 12. The selection transistor SEL can output the pixel signal of a unit pixel P to the signal line VSL. The selection transistor SEL may be electrically connected in series between the power line to which the power supply voltage VDD is supplied and the amplification transistor AMP. The selection transistor SEL may also be omitted as appropriate.

[0036] The reset transistor RST is configured to reset the voltage of the floating diffusion FD. The reset transistor RST is electrically connected to a power line to which, for example, a power supply voltage VDD is supplied, and is configured to reset the charge of a unit pixel P.

[0037] The reset transistor RST is controlled by the signal SRST and can reset the charge accumulated in the floating diffusion FD and reset the voltage of the floating diffusion FD. The reset transistor RST can, for example, electrically connect the power line and the floating diffusion FD and discharge the charge accumulated in the floating diffusion FD. The reset transistor RST can also discharge the charge accumulated in the photoelectric conversion unit 12 via the transfer transistor TRG.

[0038] The pixel control unit 111 of the light detection device 1 supplies control signals to the gates of each unit pixel P, such as the transfer transistor TRG, the selection transistor SEL, and the reset transistor RST, via the control line Lread, to turn the transistors on (conducting) or off (non-conducting).

[0039] The multiple control lines Lread for each pixel row of the light detection device 1 include, as an example, wiring that transmits the signal STRG which controls the transfer transistor TRG, wiring that transmits the signal SSEL which controls the selection transistor SEL, and wiring that transmits the signal SRST which controls the reset transistor RST.

[0040] The readout circuit 31 may be configured to allow changing the conversion efficiency (gain) when converting charge to voltage. For example, the readout circuit 31 may have a switching transistor used to set the conversion efficiency. As an example, the switching transistor is electrically connected between the floating diffusion FD and the reset transistor RST.

[0041] In the readout circuit 31, when the switching transistor is turned on, the capacitance added to the floating diffusion FD of the unit pixel P increases, and the conversion efficiency is switched. The switching transistor can change the conversion efficiency by switching the capacitance connected to the gate of the amplification transistor AMP.

[0042] The transfer transistor TRG, selection transistor SEL, reset transistor RST, and switching transistors are controlled on and off by the pixel control unit 111. The pixel control unit 111 controls the readout circuit 31 of each unit pixel P to output a pixel signal from each unit pixel P to the signal line VSL. The pixel control unit 111 can control the reading of the pixel signal from each unit pixel P to the signal line VSL.

[0043] [Configuration of the Photodetector] Figure 4 schematically shows an example of the cross-sectional configuration of the photodetector 1 of the present disclosure. Figure 5 schematically shows an example of the planar configuration of the photodetector 1 shown in Figure 4. The photodetector 1 is, for example, a back-illuminated imaging device as described above, and each of the multiple unit pixels P arranged in a matrix in two dimensions in the pixel array 100 has a configuration in which, for example, a light-receiving section 10, an optical layer 20 provided on the light-incident side S1 of the light-receiving section 10 and a multilayer wiring layer 30 provided on the side opposite to the light-incident side S1 of the light-receiving section 10 are stacked. The optical layer 20 includes, for example, a light-guide section 26 which is composed of a plurality of structures 27 that are nanostructures and a medium 28 that fills the spaces between adjacent structures 27.

[0044] Here, the light guide 26 corresponds to a specific example of the "light guide" as one embodiment of the present disclosure. The structure 27 corresponds to a specific example of the "structure" as one embodiment of the present disclosure, and the medium 28 corresponds to a specific example of the "medium" as one embodiment of the present disclosure.

[0045] The light-receiving unit 10 includes a semiconductor substrate 11 having opposing first surfaces 11S1 and second surfaces 11S2, and a plurality of photoelectric conversion units 12 embedded in the semiconductor substrate 11. The light-receiving unit 10 further includes a separation unit 13.

[0046] The semiconductor substrate 11 is made of, for example, a silicon substrate (Si). The semiconductor substrate 11 may also be an SOI (Silicon On Insulator) substrate, a SiGe (Silicon Germanium) substrate, a SiC (Silicon Carbide) substrate, etc. The semiconductor substrate 11 may be made of a compound semiconductor material of group III-V, or it may be formed using other semiconductor materials. The first surface 11S1 of the semiconductor substrate 11 is the light-receiving surface (light incident surface). The second surface 11S2 of the semiconductor substrate 11 is the element formation surface on which elements such as transistors are formed. A gate electrode, a gate insulating film, etc., are provided on the second surface 11S2 of the semiconductor substrate 11.

[0047] The photoelectric conversion unit 12 corresponds to one specific example of the "photoelectric conversion unit" as one embodiment of the present disclosure. The photoelectric conversion unit 12 is, for example, a Positive Intrinsic Negative (PIN) type photodiode (PD) and has a pn junction in a predetermined region of the semiconductor substrate 11. The photoelectric conversion unit 12 is formed by embedding one unit for each unit pixel P, for example.

[0048] The separation section 13 is provided between adjacent unit pixels P. In other words, the separation section 13 is provided so as to surround the unit pixels P, and in the pixel array section 100, it is provided, for example, in a grid pattern. The separation section 13 electrically and optically separates adjacent unit pixels P, and extends, for example, from the first surface 11S1 side to the second surface 11S2 side of the semiconductor substrate 11.

[0049] The separation portion 13 can be formed, for example, by diffusing p-type impurities. Alternatively, the separation portion 13 may be a shallow trench isolation (STI) structure or a full trench isolation (FFTI) structure, for example, in which an opening is formed in the semiconductor substrate 11 from the first surface 11S1 side and an insulating film is embedded. Furthermore, an air gap may be formed within the STI structure and the FFTI structure.

[0050] A dielectric layer 14 is further provided on the first surface 11S1 of the semiconductor substrate 11, which also serves to prevent reflection on the first surface 11S1 of the semiconductor substrate 11. The dielectric layer 14 may be, for example, a film having a positive fixed charge or a film having a negative fixed charge.

[0051] Examples of constituent materials for the dielectric layer 14 include semiconductor materials or conductive materials having a band gap wider than the band gap of the semiconductor substrate 11. Specifically, for example, hafnium oxide (HfO) ｘ ), aluminum oxide (AlO ｘ ), zirconium oxide (ZrO ｘ ), tantalum oxide (TaO ｘ ), titanium oxide (TiO ｘ ), lanthanum oxide (LaO ｘ ), praseodymium oxide (ProOｘ ), cerium oxide (CeO ｘ ), neodymium oxide (NdO ｘ ), promethium oxide (PmO ｘ ), samarium oxide (SmO ｘ ), europium oxide (EuO ｘ ), gadolinium oxide (GdO ｘ ), terbium oxide (TbO ｘ ), dysprosium oxide (DyO ｘ ), holmium oxide (HoO ｘ ), thulium oxide (TmO ｘ ), ytterbium oxide (YbO ｘ ), lutetium oxide (LuO ｘ ), yttrium oxide (YO ｘ ), hafnium nitride (HfN ｘ ), aluminum nitride (AlN ｘ ), hafnium oxynitride (HfO ｘ N ｙ ), and aluminum oxynitride (AlO ｘ N ｙ ), etc. The dielectric layer 14 may be a single-layer film or a laminated film made of different materials.

[0052] The optical layer 20 includes, for example, a light-shielding film 21, a partition wall 22, a color filter 23, a spacer layer 24, a planarization layer 25, and a light guide portion 26, and is configured to guide the light incident from the light incident side S1 to the light receiving portion 10 side.

[0053] The light-shielding film 21 is for preventing the light obliquely incident from the light incident side S1 from leaking into other adjacent unit pixels P, and is provided between adjacent unit pixels P in a plan view, for example, in the same manner as the separation portion 13. That is, the light-shielding film 21 is provided, for example, in a lattice shape. The light-shielding film 21 is provided between the light receiving portion 10 (specifically, the dielectric layer 14) and the partition wall 22 in a cross-sectional view. The light-shielding film 21 can be formed using, for example, tungsten (W), silver (Ag), copper (Cu), titanium (Ti), aluminum (Al), or their alloys.

[0054] The partition wall 22 is a frame provided at the boundary between adjacent unit pixels P, and has an opening 32H for each unit pixel P. In other words, the partition wall 22, like the separation section 13 and the light-shielding film 21, is provided to surround the unit pixels P, and is provided, for example, in a grid pattern.

[0055] The partition wall 22 is designed to prevent light incident at an oblique angle from the light incident side S1 from leaking into adjacent unit pixels P. The partition wall 22 is constructed, for example, using a material with a lower refractive index than the color filter 23.

[0056] The partition wall 22 may also serve to shield the unit pixel P that determines the optical black level. In that case, the light-shielding film 21 described above can be omitted. When the partition wall 22 also serves as the light-shielding film 21, the partition wall 22 is formed using, for example, a light-shielding material. Examples of such materials include tungsten (W), silver (Ag), copper (Cu), titanium (Ti), aluminum (Al), or alloys thereof. In addition, metal compounds such as TiN can be used as materials to form the partition wall 22. The partition wall 22 may be configured as, for example, a single layer or a multilayer film. In the case of a multilayer film, for example, a layer made of Ti, tantalum (Ta), W, cobalt (Co), or molybdenum (Mo), or alloys thereof, nitrides, oxides, or carbides may be provided as an underlayer.

[0057] The color filter 23 is configured to selectively transmit light in a predetermined wavelength range from the incident light. The color filter 23 is an RGB color filter, an infrared light transmitting filter, etc. The color filter 23 is provided above the photoelectric conversion unit 12, for example, for each unit pixel P or for each of several unit pixels P (i.e., for each predetermined number of unit pixels P).

[0058] The pixel array section 100 of the light detection device 1 includes, for example, a plurality of unit pixels P, which are provided in the pixel array section 100 of the light detection device 1. These include a unit pixel Pr (R pixel) provided with a color filter (red filter 23R) that transmits red (R) light, a unit pixel Pg (G pixel) provided with a color filter (green filter 23G) that transmits green (G) light, and a unit pixel Pb (B pixel) provided with a color filter (blue filter 23B) that transmits blue (B) light. In the pixel array section 100, a plurality of unit pixels Pr, a plurality of unit pixels Pg, and a plurality of unit pixels Pb are arranged repeatedly.

[0059] Here, red (R) light corresponds to a specific example of "light in the first wavelength band" as one embodiment of the present disclosure. Unit pixel Pr corresponds to a specific example of "first pixel" as one embodiment of the present disclosure, and red filter 23R corresponds to a specific example of "first filter" as one embodiment of the present disclosure. Green (G) light corresponds to a specific example of "light in the second wavelength band" as one embodiment of the present disclosure. Unit pixel Pg corresponds to a specific example of "second pixel" as one embodiment of the present disclosure, and green filter 23G corresponds to a specific example of "second filter" as one embodiment of the present disclosure. Blue (B) light corresponds to a specific example of "light in the third wavelength band" as one embodiment of the present disclosure. Unit pixel Pb corresponds to a specific example of "third pixel" as one embodiment of the present disclosure, and blue filter 23B corresponds to a specific example of "third filter" as one embodiment of the present disclosure.

[0060] The unit pixels Pr, Pg, and Pb are arranged, for example, according to a Bayer array. In the pixel array section 100, 2x2 pixels, each consisting of one unit pixel Pr, two unit pixels Pg, and one unit pixel Pb, are repeatedly provided. In the 2x2 pixels, as shown in Figure 5, two unit pixels Pg are arranged in one diagonal direction, and one unit pixel Pr and one unit pixel Pb are arranged in the other diagonal direction. In other words, the pixel array section 100 has, for example, pixel rows in which unit pixels Pg and unit pixels Pr are arranged alternately, and pixel rows in which unit pixels Pb and unit pixels Pg are arranged alternately (see, for example, Figure 11).

[0061] The unit pixels Pr, P, and Pb of the pixel array 100 can generate pixel signals of the R component, G component, and B component, respectively. The photodetector 1 can obtain RGB pixel signals. Note that the arrangement of the unit pixels P is not limited to the example described above and can be set arbitrarily.

[0062] For example, the unit pixels Pr, Pg, and Pb may each be arranged in 2x2 pixel units. In the pixel array unit 100, as an example shown in Figure 31, one set of unit pixels Pr, two sets of unit pixels Pg, and one set of unit pixels P are arranged in 2x2 pixel units according to the Bayer array. In the photodetector 1, one photoelectric conversion unit 12 is provided for each unit pixel P. However, as described above, if the unit pixels Pr, Pg, or Pb, which can generate pixel signals of the same components, are each arranged in 2x2 pixel units, then it can be said that each unit pixel Pr, Pg, and Pb is provided with multiple photoelectric conversion units 12 (in this case, four photoelectric conversion units 12 arranged in 2x2) that independently detect the corresponding RGB light.

[0063] The color filter 23 provided in the unit pixel P of the pixel array 100 is not limited to primary color (RGB) color filters, but may also be complementary color filters such as Cy (cyan), Mg (magenta), and Ye (yellow). A filter corresponding to W (white), that is, a filter that transmits light across the entire wavelength range of incident light, may also be provided. The color filter 23 may also be a filter that transmits infrared light.

[0064] In addition, the color filter 23 may be omitted in the light detection device 1 if necessary. For example, depending on the characteristics of the light guide unit 26, it may not be necessary to provide the color filter 23 in some or all of the unit pixels P of the light detection device 1. Furthermore, the color filter 23 may not be provided in pixels (unit pixels Pw) that receive white (W) light and perform photoelectric conversion.

[0065] The spacer layer 24 is provided between the light-receiving section 10 and the light-guiding section 26. The spacer layer 24 is formed to be laminated on, for example, the partition wall 22 and the color filter 23. The spacer layer 24 can be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), aluminum oxide (AlO), etc.

[0066] The spacer layer 24 may be formed using a material with a low refractive index in addition to the insulating material described above, or it may be formed of another material that transmits light in the wavelength range to be measured. The spacer layer 24 can also be called a transparent layer that transmits light. The thickness of the spacer layer 24 is, for example, 2 μm or more and 3 μm or less.

[0067] The planarization layer 25 is for planarizing the surface of the spacer layer 24. The planarization layer 25 can be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), aluminum oxide (AlO), etc.

[0068] The light guide section 26 is configured as an optical element capable of guiding light by, for example, imparting a phase delay to the incident light. The light guide section 26 is a light guide element utilizing metamaterial (metasurface) technology. The light guide section 26 can also be called a metasurface layer (or metamaterial layer).

[0069] The light guide unit 26 has a plurality of structures 27 and a medium 28 that fills the spaces between the plurality of structures 27. The light guide unit 26 uses the plurality of structures 27, which are nanostructures, to propagate light towards the photoelectric conversion unit 12. Light from the object to be measured is incident on the light guide unit 26. Light that has passed through an optical system such as an imaging lens is incident on the plurality of structures 27. The plurality of structures 27 have a size that is less than or equal to a predetermined wavelength of the incident light, for example, a size that is less than or equal to the wavelength range of visible light. The plurality of structures 27 may also have a size that is less than or equal to the wavelength range of infrared light.

[0070] The multiple structures 27 are, for example, columnar (pillar-shaped) structures having a circular planar shape, and can be called metasurface elements. The multiple structures 27 may, as an example, have a cylindrical shape. The multiple structures 27 are arranged so as to be aligned with each other in the X-axis direction or the Y-axis direction, with the medium 28 in between.

[0071] The shapes of the multiple structures 27 can be changed as appropriate, and each may be circular or square in plan view. The shapes of the multiple structures 27 may also be elliptical, polygonal, cross-shaped, or other shapes (for example, freeform).

[0072] The multiple structures 27 are also referred to as metaatoms, nanoatoms, nanoposts, metasurface structures, microstructures, etc.

[0073] In the light guide section 26, multiple structures 27 are arranged at intervals less than or equal to a predetermined wavelength of incident light. As an example, the multiple structures 27 are provided at intervals less than or equal to the wavelength range of visible light in the X-axis direction and the Y-axis direction. In the case of a unit pixel P, the multiple structures 27 may be arranged at intervals less than or equal to the wavelength range of infrared light.

[0074] The multiple structures 27 have refractive indices different from those of the surrounding medium 28. For example, the multiple structures 27 have refractive indices higher than those of the medium 28.

[0075] Examples of constituent materials for the multiple structures 27 include titanium oxide (TiO), silicon, polysilicon (Poly-Si), amorphous silicon (a-Si), germanium (Ge), and the like.

[0076] The multiple structures 27 may be formed using elements such as titanium (Ti), hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), indium (In), and niobium (Nb), or their oxides, nitrides, oxynitrides, or composites thereof. The multiple structures 27 may also be formed by including other metal compounds (metal oxides, metal nitrides, etc.).

[0077] Multiple structures 27 may be formed using GaP, GaN, GaAs, SiC, etc. Multiple structures 27 may also be formed using silicon oxide (SiO), silicon nitride (SiN), silicon oxide nitride (SiON), silicon carbide (SiC), oxygen-doped silicon carbide (SiOC), or other silicon compounds.

[0078] The medium 28 is composed of, for example, an inorganic material such as an oxide, nitride, or oxynitride. The medium 28 may be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), silicon oxide nitride (SiON), silicon carbide (SiC), oxygen-doped silicon carbide (SiOC), or other silicon compounds. The medium 28 may also be formed using TEOS.

[0079] The medium 28 may be formed using a siloxane resin, a styrene resin, an acrylic resin, or the like. The medium 28 may also be composed of a material in which fluorine is contained in any of these resins. Alternatively, the medium 28 may be formed using a material in which beads (fillers) having a higher (or lower) refractive index than the resin are embedded in any of these resins.

[0080] The materials of the multiple structures 27 and the medium 28 can be selected according to the refractive index difference with the surrounding medium, the wavelength range of the incident light to be measured, etc. Note that some of the multiple structures 27 and the medium 28 may be made of air. For example, the multiple structures 27 may be made including air (voids).

[0081] The light guide unit 26 can control the wavefront of light by, for example, generating a phase delay in the incident light due to the difference in refractive index between the multiple structures 27 and the surrounding medium. The light guide unit 26 can adjust the propagation direction of light by, for example, providing a phase delay to the incident light using the multiple structures 27 and the medium 28.

[0082] The materials of the multiple structures 27 and the medium 28 (optical constants of each material), the size of the multiple structures 27 (width (diameter), height, etc.), the pitch (arrangement interval), etc. are determined so that light in a desired wavelength range from the light incident from the object to be measured travels in a desired direction. For example, the materials (refractive index), dimensions, and pitch of the multiple structures 27, and the material (refractive index) of the medium 28, etc., may be set.

[0083] As an example, in the light detection device 1, the material, size, number of arrangements, etc., of the multiple structures 27 of each unit pixel P are determined so that light of a specific wavelength band to be detected proceeds to the photoelectric conversion unit 12 of the desired unit pixel P. For example, the multiple structures 27 provided on the unit pixel Pr, unit pixel Pg, and unit pixel Pb may be formed to have different sizes (e.g., width, height), arrangement positions, etc.

[0084] The light guide unit 26 may be configured, for example, as a spectrometer (spectroscopic element) capable of spectrally separating incident light into multiple wavelength bands. The optical layer 20 (or light guide unit 26) can also be called a splitter (color splitter). The optical layer 20 can also be called a color splitter layer or a wavelength separation layer. The optical layer 20 (or light guide unit 26) can also be called an optical element configured to redirect light.

[0085] In the light guide section 26, the multiple structures 27 are arranged in a predetermined pattern for each unit pixel Pr, Pg, and Pb, as shown in Figure 5, for example. When light enters the light guide section 26, a phase difference corresponding to the wavelength is generated between the multiple structures 27 and the medium 28, and the light in each wavelength band corresponding to RGB is distributed to the corresponding unit pixels r, Pg, and Pb.

[0086] The light guide unit 26 includes, for example, an R-light focusing region R1 that focuses red wavelength light (hereinafter referred to as R-light) onto a unit pixel Pr, a G-light focusing region R2 that focuses green wavelength light (hereinafter referred to as G-light) onto a unit pixel Pg, and a B-light focusing region R3 that focuses blue wavelength light (hereinafter referred to as B-light) onto a unit pixel Pb.

[0087] Figure 6 is a conceptual diagram illustrating the spectral properties of the light guide unit 26. Figure 7 is a conceptual diagram illustrating the spectral properties of a light guide unit used in a typical photodetector. In a typical photodetector (for example, photodetector 1000A, see Figure 9) that uses a color splitter to adjust the direction of light propagation by applying a phase delay to the incident light, as in the light guide unit 26 of this embodiment, for example, the color splitter has a rectangular focusing region (focusing region R Ａ) has such that the center of the light-gathering region and the point of focus coincide. In other words, as shown in Figure 7, the light-gathering region can be said to extend symmetrically in the X-axis and Y-axis directions at a distance p from the point of focus. On the other hand, in the light detection device 1 of this embodiment, the light-gathering region of the light guide unit 26 (for example, the R-light focusing region R1 that focuses R-light onto the unit pixel Pr) is the light-gathering region R shown in Figure 7. Ａ Although it has a similar rectangular shape, the focal point (for example, focal point F1) is configured to be offset from the center of the focal region by, for example, coordinates (a, b), as shown in Figure 6. In other words, the focal region can be said to extend asymmetrically from the focal point.

[0088] Figure 8 shows the phase profile at a wavelength of 630 nm that has passed through the light guide section 26. The phase profile shown in Figure 8 is expressed by the following formula (1), where the focal point (x ｃ , y ｃ The distance (i, j) from ) can be defined by the following formula (2). For example, as shown in Figure 9, one unit pixel Pr, two unit pixels Pg, and one unit pixel Pb are arranged in a Bayer pattern, and the light-gathering region R Ａ Center and focal point F Ａ In the light detection device 1000A equipped with a color splitter that matches, the focusing region R Ａ This is the light-gathering region R Ａ It has a phase distribution that decreases in the direction away from the center. Also, as shown in Figure 10, for example, one set of unit pixels Pr, two sets of unit pixels Pg, and one set of unit pixels arranged in a 2x2 pixel unit are arranged according to the Bayer array, and the light-gathering region R Ｂ Center and focal point F Ｂ Similarly, for the light detection device 1000B equipped with a color splitter that matches, the focusing region R Ｂ This is the light-gathering region R ＢIt has a phase distribution that decreases in the direction away from the center. On the other hand, in the light detection device 1 of this embodiment, the R-light focusing region R1 has a phase distribution that decreases mainly in the part shifted from the center of the R-light focusing region R1. Specifically, the R-light focusing region R1 has a phase distribution that decreases mainly in the part shifted from the center of the R-light focusing region R1 by a distance greater than 0 and less than or equal to 1 / √2 of the pixel pitch connected to the same wavelength as the unit pixel Pr. Here, "pixel pitch connected to the same wavelength" refers to the width of a pixel on which a color filter of the same color (for example, a red filter 23R) is provided. When the red filter 23R is arranged across multiple adjacent pixels, the multiple pixels on which the red filter 23R is arranged are considered as one pixel, and the total width of those multiple pixels becomes the "pixel pitch connected to the same wavelength".

[0089]

[0090] The following describes the focusing of R light, G light, and B light onto the corresponding unit pixels Pr, Pg, and Pb by the light guide unit 26.

[0091] Figure 11 shows the R-light focusing region R1 and the R-light focusing point (focal point) F1 of the light guide unit 26 that focuses 600 nm wavelength light (R-light) onto a unit pixel Pr. The R-light focusing region R1 corresponds to a specific example of the "first wavelength focusing region" as one embodiment of this disclosure. As shown in Figure 11, the R-light focusing region R1 has a larger area than the area of ​​the unit pixel Pr, and the light guide unit 26 has the R-light focusing point F1 at the center of the unit pixel Pr. Specifically, the R-light focusing region R1 is approximately equal to the area of ​​four unit pixels P arranged in a 2x2 grid including the unit pixel Pr. In other words, the R-light focusing region R1 has an area approximately four times that of the unit pixel P. Furthermore, in a plan view, as shown in Figure 11, the R-light focusing region R1 is approximately equal to the formation region of the four unit pixels P arranged in a 2x2 grid including the unit pixel Pr. In other words, the light guide section 26, which includes the R-light focusing region R1, has a focusing point F1 for R-light at a position shifted by 0.5 pixels in the X-axis and Y-axis directions from the center of the R-light focusing region R1 (a, b = -0.5, 0.5). In other words, it can be said that the R-light focusing region R1 extends asymmetrically from the focusing point F1 for R-light.

[0092] Figure 12 shows the G-light focusing region R2 and the G-light focusing point F2 of the light guide unit 26 that focuses 500 nm wavelength light (G-light) onto a unit pixel Pg. The G-light focusing region R2 corresponds to a specific example of the "second wavelength focusing region" as one embodiment of this disclosure. As shown in Figure 12, the G-light focusing region R2 has a larger area than the area of ​​the unit pixel Pg. Specifically, the G-light focusing region R2, like the R-light focusing region R1, is approximately equal to the area of ​​four unit pixels P arranged in a 2x2 grid including the unit pixel Pg. In other words, the G-light focusing region R2 has an area approximately four times that of the unit pixel P. Furthermore, in a plan view, as shown in Figure 12, the G-light focusing region R2 is approximately equal to the formation region of the four unit pixels P arranged in a 2x2 grid including the unit pixel Pg. The light guide 26, which includes the G-light focusing region R2, has a G-light focusing point (focal point) F2 at the center of two unit pixels Pg arranged diagonally in a repeating 2x2 pixel array. In other words, the light guide 26, which includes the G-light focusing region R2, has a G-light focusing point F2 at the center of the G-light focusing region R2 (center of the focusing region) (a, b = 0, 0). In other words, the G-light focusing region R2 can be said to extend symmetrically from the G-light focusing point F1.

[0093] Figure 13 shows the B-light focusing region R3 and the B-light focusing point F3 of the light guide unit 26 that focuses 400 nm wavelength light (B-light) onto a unit pixel Pb. The B-light focusing region R3 corresponds to one specific example of the "third wavelength focusing region" as one embodiment of this disclosure. As shown in Figure 13, the R-light focusing region R1 and the B-light focusing region R3 have a larger area than the area of ​​the unit pixel Pb, and the light guide unit 26 including the B-light focusing region R3 has a B-light focusing point (focal point) F3 at the center of the unit pixel Pb. Specifically, the B-light focusing region R3, like the R-light focusing region R1, is approximately equal to the area of ​​four unit pixels P arranged in a 2x2 grid including the unit pixel Pb. In other words, the B-light focusing region R3 has an area approximately four times that of the unit pixel P. Furthermore, in a plan view, the B-light focusing region R3 substantially coincides with the formation region of four unit pixels P arranged in a 2x2 grid, including this unit pixel Pb, as shown in Figure 11. In other words, the light guide section 26, which includes the B-light focusing region R3, has a B-light focusing point F3 at a position shifted by 0.5 pixels in the X-axis and Y-axis directions from the center of the B-light focusing region R3 (a, b = 0.5, -0.5). In other words, it can be said that the B-light focusing region R3 extends asymmetrically from the B-light focusing point F3.

[0094] As shown in Figures 11 to 13, the R-light focusing region R1, G-light focusing region R2, and B-light focusing region R3 of the light guide 26 described above substantially coincide with the formation regions of four unit pixels P arranged in a 2x2 grid, each containing the corresponding unit pixel P. In other words, the R-light focusing region R1, G-light focusing region R2, and B-light focusing region R3 of the light guide 26 contain the same 2x2 pixels in a plan view and overlap each other.

[0095] The multiple structures 27 may, for example, be arranged in the OPB region surrounding the pixel array 100. By arranging the multiple structures 27 in the OPB region as well, the deformation of the multiple structures 27 arranged at the periphery of the pixel array 100 is prevented, and multiple structures 27 with a uniform shape are formed throughout the entire pixel array 100. In addition, the multiple structures 27 arranged in the OPB region reduce flare caused by surface reflection at the light guide portion 26 that extends to the periphery.

[0096] An anti-reflective coating 39 is provided on the light incident side S1 of the light guide section 26. The anti-reflective coating 39 is provided so as to cover the light incident surface of the light guide section 26 and reduces (suppresses) reflection. The anti-reflective coating 39 is made of a silicon compound such as silicon nitride (SiN) or silicon oxide (SiO). The anti-reflective coating 39 may also be made of a metal compound or other material. The anti-reflective coating 39 may be made by laminating multiple films.

[0097] The multilayer wiring layer 30 is laminated on the second surface 11S2 side of the semiconductor substrate 11. The multilayer wiring layer 30 includes, for example, a conductive film and an insulating film, and has a plurality of wirings and vias. The multilayer wiring layer 30 has a configuration in which a plurality of wirings are laminated with an insulating film acting as an interlayer insulating film. The multilayer wiring layer 30 includes, for example, two or three or more layers of wiring.

[0098] The wiring of the multilayer wiring layer 30 is formed using metallic materials such as aluminum (Al), copper (Cu), and tungsten (W). Alternatively, the wiring of the multilayer wiring layer 30 may be constructed using polysilicon (Poly-Si) or other conductive materials. The interlayer insulating film can be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), or silicon oxynitride (SiON).

[0099] The semiconductor substrate 11 and the multilayer wiring layer 30 are provided with, for example, the above-described readout circuit 31 for each unit pixel P or for each of multiple unit pixels P. In addition to the above-described readout circuit 31, the multilayer wiring layer 30 may also be formed with, for example, a pixel control unit 111, a signal processing unit 112, a control unit 113, and a processing unit 114.

[0100] [Effects and Actions]

[0101] In recent years, pixel miniaturization has been progressing in imaging devices in which four unit pixels Pr, eight unit pixels Pg, and four unit pixels P are arranged in a 2x2 pixel unit according to a Bayer array, from the perspective of both power consumption and image quality.

[0102] However, in the above imaging device, color filters of the same color are arranged side by side. Therefore, as pixels become smaller, the mixing of colors between pixels of the same color deteriorates, and the resolution between pixels of the same color cannot be maintained, resulting in a degradation of image quality. Furthermore, not limited to the above imaging device, image quality degradation due to decreased sensitivity associated with pixel miniaturization is a problem in general imaging devices as well.

[0103] In contrast, the light detection device 1 of this embodiment uses a light guide unit 26 that includes an R-light focusing region R1 that focuses light of a predetermined wavelength band (for example, R-light) from the incident light onto a unit pixel Pr, and has a focusing point F1 where the light from the R-light focusing region R1 is focused, approximately at the center of the unit pixel Pr. The R-light focusing region R1 has an area larger than the area of ​​the unit pixel Pr and extends asymmetrically from the focusing point F1. As a result, in addition to the R-light incident from above the unit pixel Pr, the R-light incident on the surrounding unit pixels (unit pixels Pg, unit pixels Pb) is also focused onto the unit pixel Pr.

[0104] As a result of the above, the light detection device 1 of this embodiment makes it possible to improve image quality.

[0105] Furthermore, in this embodiment, the light guide unit 26 includes, in addition to the R-light focusing region R1, a G-light focusing region R2 for focusing G-light onto a unit pixel Pg and a B-light focusing region R3 for focusing B-light onto a unit pixel Pb. The G-light focusing region R2 and the B-light focusing region R3 each have an area larger than the area of ​​a unit pixel Pr, similar to the R-light focusing region R1, and overlap each other.

[0106] When such a light guide unit 26 is used, for example, in a photodetector (photodetector 1) with a pixel pitch of 0.7 μm or less, it is possible to improve image quality while reducing power consumption compared to a general imaging device having the same pixel pitch.

[0107] For example, when generating image data by reading out the signals of all pixels, the light detection device 1 can achieve equivalent resolution by, for example, rearranging or demosaicing, compared to an imaging device (imaging device 1000C) which has a Bayer array and acquires RGB color information by a color filter without using a color splitter, or an imaging device (imaging device 1000D) such as the light detection device 1000B, in which one set of unit pixels Pr, two sets of unit pixels Pg, and one set of unit pixels P arranged in a 2x2 pixel unit are arranged according to a Bayer array and acquire RGB color information by a color filter without using a color splitter. Furthermore, since the light detection device 1 collects corresponding RGB light from surrounding pixels, it can improve sensitivity compared to imaging devices 1000C and 1000D. Furthermore, when reading out the signals from all pixels to generate image data, the imaging device 1000C performs demosaicing, and the imaging device 1000D performs remosaicing and demosaicing, which increases power consumption. In contrast, the light detection device 1 can generate image data without performing demosaicing, thus suppressing power consumption.

[0108] Furthermore, for example, in the 48M imaging device 1000D, as shown in Figure 14, if adjacent pixels of the same color are added together to generate image data, image data equivalent to 12M can be generated while suppressing power consumption. In the imaging device 1000C having a Bayer array, if the RGBW signals are read out in 2x2 pixel units, similar to the imaging device 1000D, one of the unit pixels Pr, Pg, or Pb is selected and read out in 2x2 pixel units, as shown in Figure 15(A). Therefore, unlike the imaging device 1000D, the center of the RGB signal (marked with a star in the figure) is shifted from the center of the 2x2 pixel, as shown in Figure 15(B), resulting in a significant degradation of resolution. In the imaging device 1000C, as shown in Figure 16(B), in order for the center of the RGB signal to be the center of the 2x2 pixel, an addition process is required to correct the centroid of the signal. For example, as shown in Figure 16(A), all unit pixels Pr and Pb are read out except for the two unit pixels Pg arranged within the 2x2 pixel.

[0109] In contrast, when the RGB signals are read out in 2x2 pixel units in the same 48M photodetector 1 as in the imaging device 1000D, although the center of the RGB signals is offset from the center of the 2x2 pixels, as shown in Figure 17(A), the light of the colors corresponding to RGB is collected from the light incident within the light-gathering region. Therefore, the effective center of the RGB signals can be considered to be the center of the 2x2 pixels, as shown in Figure 17(B). Furthermore, since the photodetector 1 can collect light from each of the RGBW colors from the entire area of ​​the 2x2 pixels, it can obtain higher sensitivity than the imaging device 1000C.

[0110] Next, modifications 1 to 5 of the present disclosure, as well as examples of application and application, 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.

[0111] <2. Modified Examples> (2-1. Modified Example 1) Figure 18 shows the R-light focusing region R1 and the R-light focusing point F1 of the light guide unit 26A that focuses 600 nm light (R-light) onto a unit pixel Pr according to Modified Example 1 of this disclosure. Figure 19 shows the G-light focusing region R2 and the B-light focusing point F2 of the light guide unit 26A that focuses 500 nm light (G-light) onto a unit pixel Pg according to Modified Example 1 of this disclosure. Figure 20 shows the B-light focusing region R3 and the B-light focusing point F3 of the light guide unit 26A that focuses 400 nm light (B-light) onto a unit pixel Pb according to Modified Example 1 of this disclosure.

[0112] In the above embodiment, the R-light focusing region R1, the G-light focusing region R2, and the B-light focusing region R3 all have a rectangular shape and substantially coincide with the formation region of four unit pixels P arranged in a 2x2 grid, each containing the corresponding unit pixel P. However, the embodiment is not limited to this. As shown in Figure 19, the light guide section (light guide section 26A) of this modified example includes two G-light focusing regions R2a and R2b, each having a triangular shape with the centers of two unit pixels Pg arranged diagonally in a 2x2 pixel repeating unit as the centers of their respective focusing regions. Except for this point, the light guide section 26A has substantially the same configuration as the light guide section 26 of the above embodiment.

[0113] In this modified example, the centers of the G-light focusing regions R2a and R2b, respectively, and the G-light focusing point F2 are approximately coincident. Furthermore, the R-light focusing region R1, the G-light focusing regions R2a and R2b, and the B-light focusing region R3 overlap each other.

[0114] Even with this configuration, the light detection device equipped with the light guide unit 26A can obtain the same effects as in the above embodiment.

[0115] (2-2. Modification 2) Figure 21 shows the R-light focusing region R1 and the R-light focusing point F1 of the light guide unit 26B that focuses 600 nm light (R-light) onto a unit pixel Pr according to Modification 2 of the present disclosure. Figure 22 shows the G-light focusing region R2 and the B-light focusing point F2 of the light guide unit 26B that focuses 500 nm light (G-light) onto a unit pixel Pg according to Modification 2 of the present disclosure. Figure 23 shows the B-light focusing region R3 and the B-light focusing point F3 of the light guide unit 26B that focuses 400 nm light (B-light) onto a unit pixel Pb according to Modification 2 of the present disclosure.

[0116] In the above embodiment, the R-light focusing region R1, G-light focusing region R2, and B-light focusing region R3 of the light guide unit 26 all have a rectangular shape and substantially coincide with the formation region of four unit pixels P arranged in a 2x2 grid, each containing the corresponding unit pixel P. However, the embodiment is not limited to this. As shown in Figure 22, the light guide unit of this modified example (light guide unit 26B) includes two G-light focusing regions R2c and R2d, each with the center of the focusing region being the center of two unit pixels Pg arranged diagonally in a 2x2 pixel repeating unit. The two G-light focusing regions R2c and R2d have a substantially rectangular shape rotated 45° with respect to the pixel arrangement direction. Except for this point, the light guide unit 26B has substantially the same configuration as the light guide unit 26 of the above embodiment.

[0117] In this modified example, the centers of the G-light focusing regions R2c and R2d, respectively, coincide approximately with the G-light focusing point F2. The R-light focusing region R1 and B-light focusing region R3 and the G-light focusing regions R2c and R2d partially overlap.

[0118] Even with this configuration, the light detection device equipped with the light guide unit 26B can obtain the same effects as in the above embodiment.

[0119] (2-3. Modification 3) Figure 24 shows the R-light focusing region R1 and the R-light focusing point F1 of the light guide unit 26C that focuses 600 nm light (R-light) onto a unit pixel Pr according to Modification 3 of the present disclosure. Figure 25 shows the G-light focusing region R2 and the B-light focusing point F2 of the light guide unit 26C that focuses 500 nm light (G-light) onto a unit pixel Pg according to Modification 3 of the present disclosure. Figure 26 shows the B-light focusing region R3 and the B-light focusing point F3 of the light guide unit 26C that focuses 400 nm light (B-light) onto a unit pixel Pb according to Modification 3 of the present disclosure.

[0120] In the above embodiment, the R-light focusing region R1, G-light focusing region R2, and B-light focusing region R3 of the light guide 26 all have a rectangular shape and are shown to substantially coincide with the formation region of four unit pixels P arranged in a 2x2 grid, each containing a corresponding unit pixel P. However, the embodiment is not limited to this. The light guide (light guide 26C) of this modified example includes two G-light focusing regions R2e and R2f, similar to the above modified examples 1 and 2. As shown in Figure 25, the G-light focusing region R2e substantially coincides with the formation region of a repeating 2x2 pixel, for example, a unit pixel Pg located in the upper right of the page and a unit pixel Pr adjacent in the X-axis direction. As shown in Figure 25, the G-light focusing region R2f substantially coincides with the formation region of a repeating 2x2 pixel, for example, a unit pixel Pg located in the lower left of the page and a unit pixel Pb adjacent in the X-axis direction. In this modified example, the G-light focusing points F2 are located at positions (a, b = 0.5, 0) or (a, b = -0.5, 0) that are offset from the centers of the G-light focusing regions R2e and R2f in the X-axis and Y-axis directions, respectively. In other words, the G-light focusing regions R2e and R2f can be said to extend asymmetrically from the G-light focusing point F2. Except for this point, the light guide portion 26C has substantially the same configuration as the light guide portion 26 in the above embodiment.

[0121] Even with this configuration, the light detection device equipped with the light guide section 26C can obtain the same effects as in the above embodiment.

[0122] (2-4. Modification 4) Figure 27 shows the R-light focusing region R1 and the R-light focusing point F1 of the light guide unit 26D that focuses 600 nm light (R-light) onto a unit pixel Pr according to Modification 4 of this disclosure. Figure 28 shows the G-light focusing region R2 and the B-light focusing point F2 of the light guide unit 26D that focuses 500 nm light (G-light) onto a unit pixel Pg according to Modification 4 of this disclosure. Figure 29 shows the B-light focusing region R3 and the B-light focusing point F3 of the light guide unit 26D that focuses 400 nm light (B-light) onto a unit pixel Pb according to Modification 4 of this disclosure. Figure 30 shows the IR-light focusing region R4 and the IR-light focusing point F4 of the light guide unit 26D that focuses 1300 nm light (IR-light) onto a unit pixel Pb according to Modification 4 of this disclosure.

[0123] The modified photodetector 1A includes, in addition to the unit pixels Pr, Pg, and Pb, a unit pixel Pir (infrared pixel) that is equipped with a color filter that transmits infrared light (IR), for example. In the pixel array section 100, 2x2 pixels, each consisting of one unit pixel Pr, one unit pixel Pg, one unit pixel Pb, and one unit pixel Pir, are repeatedly provided. In the 2x2 pixels, for example, as shown in Figure 27, unit pixels Pr and Pb are arranged in one diagonal direction, and unit pixels Pg and Pir are arranged in the other diagonal direction. The light guide section (light guide section 26D) of this modified example includes an IR light focusing area R4 in addition to the R light focusing area R1, G light focusing area R2, and B light focusing area R3. The light guide unit 26D further has corresponding focal points F1, F2, F3, and F4 for R light, G light, B light, and IR light at the center of each unit pixel Pr, Pg, Pb, and Pir, respectively, and the R light focal area R1, G light focal area R2, B light focal area R3, and IR light focal area R4 extend asymmetrically from the respective focal points F1, F2, F3, and F4 for R light, G light, B light, and IR light. Except for this point, the light detection device 1A and the light guide unit 26D have substantially the same configuration as the light detection device 1 and the light guide unit 26 of the above embodiment.

[0124] Even with this configuration, the light detection device equipped with the light guide unit 26D can obtain the same effects as in the above embodiment.

[0125] (2-5. Modification 5) Figure 31 shows the R-light focusing region R1 and the R-light focusing point F1 of the light guide unit 26 that focuses 600 nm light (R-light) onto a unit pixel Pr according to Modification 5 of the present disclosure. Figure 32 shows the G-light focusing region R2 and the B-light focusing point F2 of the light guide unit 26 that focuses 500 nm light (G-light) onto a unit pixel Pg according to Modification 5 of the present disclosure. Figure 33 shows the B-light focusing region R3 and the B-light focusing point F3 of the light guide unit 26 that focuses 400 nm light (B-light) onto a unit pixel Pb according to Modification 5 of the present disclosure.

[0126] This technology, in which one set of unit pixels Pr, two sets of unit pixels Pg, and one set of unit pixels P are arranged in a 2x2 pixel unit, according to a Bayer array, can also be applied to a photodetector (photodetector 1B). For example, the same effect as in the above embodiment can be obtained when the photodetector 1B generates image data by adding adjacent pixels of the same color.

[0127] <3. Application Examples>

[0128] (Application Example 1) Furthermore, the light detection device described above (for example, light detection device 1) can be applied to various electronic devices such as imaging systems such as digital still cameras and digital video cameras, mobile phones equipped with imaging functions, or other devices equipped with imaging functions.

[0129] Figure 34 is a block diagram showing an example of the configuration of the electronic device 1000.

[0130] As shown in Figure 34, the electronic device 1000 includes an optical system 1001, a light detection device 1, and a DSP (Digital Signal Processor) 1002. The DSP 1002, memory 1003, display device 1004, recording device 1005, operating system 1006, and power supply system 1007 are connected via a bus 1008, and it is capable of capturing still and moving images.

[0131] The optical system 1001 is composed of one or more lenses and captures incident light (image light) from the subject and forms an image on the imaging surface of the light detection device 1.

[0132] The light detection device 1 converts the amount of incident light imaged onto the imaging surface by the optical system 1001 into an electrical signal on a pixel-by-pixel basis and supplies it to the DSP 1002 as a pixel signal.

[0133] The DSP 1002 performs various signal processing on the signal from the light detection device 1 to acquire an image, and temporarily stores the image data in the memory 1003. The image data stored in the memory 1003 is recorded in the recording device 1005 or supplied to the display device 1004 to display the image. The operation system 1006 accepts various operations from the user and supplies operation signals to each block of the electronic device 1000, and the power supply system 1007 supplies the power necessary to drive each block of the electronic device 1000.

[0134] (Application Example 2) Figure 35A schematically shows an example of the overall configuration of a photodetection system 2000 equipped with a photodetector 1. Figure 35B shows an example of the circuit configuration of the photodetection system 2000. The photodetection system 2000 includes a light-emitting device 2001 as a light source that emits infrared light L2, and a photodetector 2002 as a light-receiving unit having a photoelectric conversion element. For example, the photodetector 1 can be used as the photodetector 2002. The photodetection system 2000 may further include a system control unit 2003, a light source drive unit 2004, a sensor control unit 2005, a light source side optical system 2006, and a camera side optical system 2007.

[0135] The photodetector 2002 can detect light L1 and light L2. Light L1 is light reflected from ambient light from the outside by the subject (object to be measured) 2100 (Figure 35A). Light L2 is light that has been emitted by the light-emitting device 2001 and then reflected by the subject 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 is detectable in the photoelectric conversion unit of the photodetector 2002, and light L2 is detectable in the photoelectric conversion region of the photodetector 2002. Image information of the subject 2100 can be obtained from light L1, and distance information between the subject 2100 and the photodetector system 2000 can be obtained from light L2. The photodetector system 2000 can be mounted on, for example, electronic devices such as smartphones or mobile devices such as cars. The light-emitting device 2001 can be, for example, a semiconductor laser, a surface-emitting semiconductor laser, or a vertical-cavity surface-emitting laser (VCSEL). As a detection method for the light L2 emitted from the light-emitting device 2001 by the photodetector 2002, for example, the iTOF method can be used, but is not limited to this. In the iTOF method, the photoelectric conversion unit can measure the distance to the subject 2100 by, for example, the time-of-flight (TOF). As a detection method for the light L2 emitted from the light-emitting device 2001 by the photodetector 2002, for example, the structured light method or the stereo vision method can also be used. For example, in the structured light method, the distance between the photodetector 2000 and the subject 2100 can be measured by projecting a predetermined pattern of light onto the subject 2100 and analyzing the degree of distortion of the pattern. In the stereo vision method, for example, the distance between the photodetector 2000 and the subject can be measured by using two or more cameras to acquire two or more images of the subject 2100 from two or more different viewpoints. Furthermore, the light-emitting device 2001 and the light-detecting device 2002 can be synchronously controlled by the system control unit 2003.

[0136] <4. Application Examples> (Application Example to Endoscopic Surgical Systems) The technology disclosed herein (this technology) can be applied to various products. For example, the technology disclosed herein may be applied to an endoscopic surgical system.

[0137] Figure 36 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.

[0138] Figure 36 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 a pneumoperitoneum 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.

[0139] 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.

[0140] An opening into which an objective lens is fitted is provided at the tip of the microscope 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 microscope tube by a light guide extending inside the microscope 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.

[0141] 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.

[0142] The CCU 11201 is composed 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 CCU 11201 receives an image signal from the camera head 11102 and performs various image processing operations on that image signal, such as development processing (demosaic processing), to display an image based on that image signal.

[0143] 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.

[0144] The light source device 11203 is composed 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.

[0145] The input device 11204 is an input interface for the endoscopic surgical system 11000. The user can input various types of 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.

[0146] The treatment instrument control device 11205 controls the drive of the energy treatment instrument 11112 for purposes such as tissue cauterization, incision, or blood vessel sealing. The insufflation device 11206 injects gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity for the purpose of securing a field of view by the endoscope 11100 and securing the operator's workspace. 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.

[0147] The light source device 11203 that supplies illumination light to the endoscope 11100 when photographing the surgical area can be configured as a white light source consisting of, for example, an LED, a laser light source, or a combination thereof. When the white light source is configured as a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so the white balance of the captured image can be adjusted in the light source device 11203. In this case, it is also possible to capture images corresponding to each of the RGB colors in time-division by irradiating the observation target with laser light from each of the RGB laser light sources in time-division and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter on the image sensor.

[0148] Furthermore, the light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. By controlling the drive of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity, images can be acquired in time-division order, and these images can be combined to generate high dynamic range images without so-called black crushing and white clipping.

[0149] Furthermore, the light source device 11203 may be configured to supply light in a predetermined wavelength range corresponding to special light observation. In special light observation, for example, so-called narrow-band imaging is performed, in which a predetermined tissue such as blood vessels on the surface of the mucosa is imaged with high contrast by irradiating with narrow-band light compared to the irradiation light used in normal observation (i.e., white light), utilizing the wavelength dependence of light absorption in body tissue. Alternatively, fluorescence observation may be performed in special light observation, in which an image is obtained from fluorescence generated by irradiation with excitation light. In fluorescence observation, fluorescence can be obtained by irradiating body tissue with excitation light and observing the fluorescence from the body tissue (autofluorescence observation), or by locally injecting a reagent such as indocyanine green (ICG) into body tissue and irradiating the body tissue with excitation light corresponding to the fluorescence wavelength of the reagent to obtain a fluorescence image. The light source device 11203 may be configured to supply narrow-band light and / or excitation light corresponding to such special light observation.

[0150] Figure 37 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU 11201 shown in Figure 36.

[0151] The camera head 11102 includes a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with each other.

[0152] The lens unit 11401 is an optical system provided at the connection point with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and then incident on the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses, including a zoom lens and a focus lens.

[0153] 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 configured as a multi-chip type, for example, each image sensor may generate image signals corresponding to RGB, and these 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 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 configured as a multi-chip type, multiple lens units 11401 may also be provided corresponding to each image sensor.

[0154] Furthermore, the imaging unit 11402 does not necessarily have to be located on the camera head 11102. For example, the imaging unit 11402 may be located inside the lens barrel 11101, directly behind the objective lens.

[0155] 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.

[0156] The communication unit 11404 is composed 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.

[0157] 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.

[0158] 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 CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with so-called AE (Auto Exposure), AF (Auto Focus), and AWB (Auto White Balance) functions.

[0159] 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.

[0160] The communication unit 11411 is comprised 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.

[0161] Furthermore, the communication unit 11411 transmits control signals to the camera head 11102 to control the driving of the camera head 11102. Image signals and control signals can be transmitted by telecommunications, optical communications, etc.

[0162] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102.

[0163] 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 a control signal to control the driving of the camera head 11102.

[0164] Furthermore, the control unit 11413 displays the captured image showing the surgical area, etc., 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 reliably.

[0165] 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.

[0166] In the illustrated example, communication was performed via a wired connection using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may be performed wirelessly.

[0167] The above describes an example of an endoscopic surgical system to which the technology described herein may be applied. The technology described herein can be applied to the imaging unit 11402 of the configuration described above. By applying the technology described herein to the imaging unit 11402, the detection accuracy is improved.

[0168] While an endoscopic surgical system has been described here as an example, the technology described herein may also be applied to other systems, such as microsurgical systems.

[0169] (Examples of application to mobile devices) The technology disclosed herein 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 device, such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, robots, construction machinery, or agricultural machinery (tractors).

[0170] Figure 38 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.

[0171] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 38, 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] The imaging unit 12031 is a light 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.

[0176] 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 captures images of 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.

[0177] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information 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 driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0178] 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.

[0179] 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.

[0180] 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 38, the output devices include 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.

[0181] Figure 39 shows an example of the installation position of the imaging unit 12031.

[0182] In Figure 39, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0183] 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.

[0184] Figure 39 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.

[0185] 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.

[0186] For example, the microcomputer 12051, based on distance information obtained from the 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 the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the 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 in front of 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, etc., that drives autonomously without driver operation, can be performed.

[0187] 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, large 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 the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0188] 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.

[0189] Although the present disclosure has been described above with reference to embodiments and modifications 1 to 5, as well as application examples and usage examples, the present technology is not limited to the above embodiments, and various modifications are possible.

[0190] For example, in the above embodiment, an example was shown in which a single layer of light guide portion 26 is provided, which has a plurality of structures 27 and a medium 28 provided around the plurality of structures 27 and having a refractive index different from that of the plurality of structures 27. However, the invention is not limited to this, and a plurality of light guide portions may be stacked.

[0191] The light detection device disclosed herein only needs to receive incident light and convert the light into an electric charge. The output signal may be an image information signal or a distance measurement information signal. The light detection device can be applied to image sensors, distance measurement sensors, etc. Furthermore, this disclosure is not limited to back-illuminated image sensors, but is also applicable to front-illuminated image sensors.

[0192] Furthermore, the light detection device according to this disclosure can also be used as a distance measuring sensor capable of measuring distance using the TOF (Time Of Flight) method. The light-receiving element (photoelectric conversion unit) of each pixel may be an APD (Avalanche Photo Diode). The light-receiving element may be composed of, for example, a SPAD (Single Photon Avalanche Diode). The light detection device can also be used as a sensor capable of detecting events, for example, an event-driven sensor (also called an EVS (Event Vision Sensor), EDS (Event Driven Sensor), DVS (Dynamic Vision Sensor), etc.).

[0193] Furthermore, the effects described herein are merely examples and are not limited to those described; other effects may also occur.

[0194] For example, the above embodiment shows an example in which one light guide portion 26 is provided in the optical layer 20, but it is not limited to this. Multiple light guide portions may be stacked in the optical layer 20 in the direction of light incidence.

[0195] Furthermore, this disclosure can also take the following configuration. According to the technology with the following configuration, in addition to light of the first wavelength band incident from above the first pixel, light of the first wavelength band incident on pixels surrounding the first pixel is focused on the first pixel. Therefore, it is possible to improve image quality. (1) A semiconductor substrate having a first surface on which light is incident and a second surface located on the opposite side of the first surface, wherein a plurality of pixels, including a first pixel that detects light of the first wavelength band from the incident light, are arranged in a two-dimensional array; and a light guide portion arranged on the first surface side of the semiconductor substrate and including a first wavelength focusing region that focuses light of the first wavelength band from the incident light onto the first pixel, wherein the light guide portion has a first focusing point where light of the first wavelength band is focused approximately at the center of the first pixel, and the first wavelength focusing region has an area larger than the area of ​​the first pixel and extends asymmetrically from the first focusing point. (2) The photodetector according to (1), wherein the phase distribution within the first wavelength focusing region decreases mainly in the portion offset from the center of the first wavelength focusing region. (3) The area of ​​the first wavelength focusing region is an n x n array (where n is an integer of 2 or more) containing the first pixel. ２ The light detection device according to (1) or (2) above, wherein the area of ​​the aforementioned pixel is approximately equal to the area of ​​the aforementioned pixel. (4) The first wavelength focusing region is an n row × n column (where n is an integer of 2 or more) including the first pixel. ２(1) or (2) above, wherein the photodetector is substantially the same as the pixel formation region of (1) or (2). (5) The photodetector is the (7) The light guide further includes a second wavelength focusing region for focusing light of the second wavelength band on the second pixel and a third wavelength focusing region for focusing light of the third wavelength band on the third pixel, and further has a second focusing point where light of the second wavelength band is focused approximately at the center of the second pixel and a third focusing point where light of the third wavelength band is focused approximately at the center of the third pixel, wherein the second wavelength focusing region has an area larger than the area of ​​the second pixel and extends symmetrically from the second focusing point, and the third wavelength focusing region has an area larger than the area of ​​the third pixel and extends asymmetrically from the third focusing point, the light detection device according to (6). (8) The light detection device according to (7), wherein the first pixel is a red pixel that detects red light as light in the first wavelength band, the second pixel is a green pixel that detects green light as light in the second wavelength band, and the third pixel is a blue pixel that detects blue light as light in the third wavelength band, and one red pixel, two green pixels and one blue pixel are arranged in a Bayer configuration in two rows and two columns. (9) The light detection device according to (8), wherein the first wavelength focusing region, the second wavelength focusing region and the third wavelength focusing region substantially coincide with and overlap the formation regions of the one red pixel, two green pixels and one blue pixel arranged in a Bayer configuration in two rows and two columns.(10) The photodetector according to (8) or (9), wherein the first wavelength focusing region and the third wavelength focusing region substantially coincide with and overlap each other with the formation regions of one red pixel, two green pixels, and one blue pixel arranged in a Bayer-like 2x2 configuration, and the second wavelength focusing region has a substantially square shape rotated by approximately 45° with respect to the second pixel, and a portion of it overlaps with the first wavelength focusing region and the third wavelength focusing region. (11) The light guide further includes a second wavelength focusing region for focusing light of the second wavelength band on the second pixel and a third wavelength focusing region for focusing light of the third wavelength band on the third pixel, and further has a second focusing point where light of the second wavelength band is focused approximately at the center of the second pixel and a third focusing point where light of the third wavelength band is focused approximately at the center of the third pixel, wherein the second wavelength focusing region has a larger area than the area of ​​the second pixel and extends asymmetrically from the second focusing point, and the third wavelength focusing region has a larger area than the area of ​​the third pixel and extends asymmetrically from the third focusing point, the light detection device according to any one of (6) to (10). (12) The light detection device according to (11), wherein the first pixel is a red pixel that detects red light as light in the first wavelength band, the second pixel is a green pixel that detects green light as light in the second wavelength band, and the third pixel is a blue pixel that detects blue light as light in the third wavelength band, and one red pixel, two green pixels and one blue pixel are arranged in a Bayer configuration in 2 rows x 2 columns. (13) The light detection device according to (12), wherein the first wavelength focusing region and the third wavelength focusing region substantially coincide with and overlap each other with the formation regions of one red pixel, two green pixels and one blue pixel arranged in a Bayer configuration in 2 rows x 2 columns, and the second wavelength focusing region substantially coincides with the formation regions of adjacent red pixels and green pixels or green pixels and blue pixels in the row direction among the one red pixel, two green pixels and one blue pixel arranged in a Bayer configuration in 2 rows x 2 columns.(14) The light detection device according to any one of (11) to (13), wherein the semiconductor substrate further includes a fourth pixel as the plurality of pixels for detecting light of a fourth wavelength band different from the first wavelength band, the second wavelength band and the third wavelength band of the incident light, the light guide further includes a fourth wavelength focusing region for focusing light of the fourth wavelength band from the incident light onto the fourth pixel, and further has a fourth focusing point where light of the fourth wavelength band is focused approximately at the center of the fourth pixel, the fourth wavelength focusing region has an area larger than the area of ​​the fourth pixel and extends asymmetrically from the fourth focusing point. (15) The light detection device according to (14), wherein the first pixel is a red pixel that detects red light as light in the first wavelength band, the second pixel is a green pixel that detects green light as light in the second wavelength band, the third pixel is a blue pixel that detects blue light as light in the third wavelength band, and the fourth pixel is an IR pixel that detects infrared light as light in the fourth wavelength band, and one red pixel, one green pixel, one blue pixel and one IR pixel are arranged in 2 rows x 2 columns. (16) The light detection device according to any one of (6) to (15), further comprising a color filter between the semiconductor substrate and the light guide, the color filter including a first filter that selectively transmits light in the first wavelength band, a second filter that selectively transmits light in the second wavelength band, and a third filter that selectively transmits light in the third wavelength band, the first filter is arranged in the first pixel, the second filter is arranged in the second pixel, and the third filter is arranged in the third pixel. (17) The light detection device according to any one of (1) to (16), wherein the light guide portion includes a plurality of structures having a size less than or equal to the wavelength of the incident light, and a medium provided to fill the space between adjacent plurality of structures and having a refractive index different from that of the plurality of structures. (18) The light detection device according to (17), wherein the plurality of structures separate the incident light into light of a plurality of wavelength bands.(19) The light detection device according to any one of (1) to (18), wherein the light guide portion includes a first light guide portion and a second light guide portion, and the light guide portion and the light guide portion are stacked in the direction of incidence of the light.

[0196] This application claims priority based on Japanese Patent Application No. 2025-007665, filed with the Japan Patent Office on January 20, 2025, and all contents of that application are incorporated herein by reference.

[0197] Those skilled in the art will understand that various modifications, combinations, subcombinations, and changes can be conceived depending on design requirements and other factors, and that these fall within the scope of the attached claims and their equivalents.

Claims

1. A light detection device comprising: a semiconductor substrate having a first surface to which light is incident and a second surface located opposite to the first surface, wherein a plurality of pixels, including a first pixel that detects light in a first wavelength band from the incident light, are arranged in a two-dimensional array; and a light guide portion disposed on the first surface side of the semiconductor substrate and including a first wavelength focusing region that focuses light in the first wavelength band from the incident light onto the first pixel, wherein the light guide portion has a first focusing point where light in the first wavelength band is focused approximately at the center of the first pixel, and the first wavelength focusing region has an area larger than the area of ​​the first pixel and extends asymmetrically from the first focusing point.

2. The photodetector according to claim 1, wherein the phase distribution within the first wavelength focusing region decreases mainly in the portion offset from the center of the first wavelength focusing region.

3. The area of ​​the first wavelength focusing region is an n x n array (where n is an integer of 2 or more) containing the first pixel. ２ The light detection device according to claim 1, wherein the area of ​​the aforementioned pixel is substantially equal to the area of ​​the aforementioned pixel.

4. The first wavelength focusing region is an n x n array (where n is an integer of 2 or more) containing the first pixel. ２ The photodetector according to claim 1, wherein the pixel formation region substantially coincides with the region of the aforementioned pixels.

5. The photodetector according to claim 1, wherein the first pixel has one or more photoelectric conversion units embedded in the semiconductor substrate that independently detect light in the first wavelength band.

6. The photodetector according to claim 1, wherein the semiconductor substrate further includes, as the plurality of pixels, a second pixel that detects light in a second wavelength band different from the first wavelength band among the incident light, and a third pixel that detects light in a third wavelength band different from the first wavelength band and the second wavelength band.

7. The light guide further includes a second wavelength focusing region for focusing light of the second wavelength band onto the second pixel and a third wavelength focusing region for focusing light of the third wavelength band onto the third pixel, and further includes a second focusing point where light of the second wavelength band is focused approximately at the center of the second pixel and a third focusing point where light of the third wavelength band is focused approximately at the center of the third pixel, wherein the second wavelength focusing region has an area larger than the area of ​​the second pixel and extends symmetrically from the second focusing point, and the third wavelength focusing region has an area larger than the area of ​​the third pixel and extends asymmetrically from the third focusing point, the light detection device according to claim 6.

8. The light detection device according to claim 7, wherein the first pixel is a red pixel that detects red light as light in the first wavelength band, the second pixel is a green pixel that detects green light as light in the second wavelength band, and the third pixel is a blue pixel that detects blue light as light in the third wavelength band, and one red pixel, two green pixels, and one blue pixel are arranged in a Bayer-like configuration in two rows and two columns.

9. The photodetector according to claim 8, wherein the first wavelength focusing region, the second wavelength focusing region, and the third wavelength focusing region substantially coincide with and overlap with the formation regions of one red pixel, two green pixels, and one blue pixel arranged in a Bayer-like 2x2 configuration.

10. The photodetector according to claim 8, wherein the first wavelength focusing region and the third wavelength focusing region substantially coincide with and overlap each other with the formation regions of one red pixel, two green pixels, and one blue pixel arranged in a Bayer-like 2x2 configuration, and the second wavelength focusing region has a substantially rectangular shape rotated by approximately 45° with respect to the second pixel, and a portion of it overlaps with the first wavelength focusing region and the third wavelength focusing region.

11. The light guide further includes a second wavelength focusing region for focusing light of the second wavelength band onto the second pixel and a third wavelength focusing region for focusing light of the third wavelength band onto the third pixel, and further has a second focusing point where light of the second wavelength band is focused approximately at the center of the second pixel and a third focusing point where light of the third wavelength band is focused approximately at the center of the third pixel, wherein the second wavelength focusing region has a larger area than the area of ​​the second pixel and extends asymmetrically from the second focusing point, and the third wavelength focusing region has a larger area than the area of ​​the third pixel and extends asymmetrically from the third focusing point, the light detection device according to claim 6.

12. The light detection device according to claim 11, wherein the first pixel is a red pixel that detects red light as light in the first wavelength band, the second pixel is a green pixel that detects green light as light in the second wavelength band, and the third pixel is a blue pixel that detects blue light as light in the third wavelength band, and one red pixel, two green pixels, and one blue pixel are arranged in a Bayer-like configuration in two rows and two columns.

13. The photodetector according to claim 12, wherein the first wavelength focusing region and the third wavelength focusing region substantially coincide with and superimpose the formation regions of one red pixel, two green pixels, and one blue pixel arranged in a Bayer-like 2x2 configuration, and the second wavelength focusing region substantially coincides with the formation regions of adjacent red pixels and green pixels or green pixels and blue pixels in the row direction among the one red pixel, two green pixels, and one blue pixel arranged in a Bayer-like 2x2 configuration.

14. The photodetector according to claim 11, wherein the semiconductor substrate further includes a fourth pixel as the plurality of pixels for detecting light of a fourth wavelength band different from the first wavelength band, the second wavelength band, and the third wavelength band from the incident light, the light guide further includes a fourth wavelength focusing region for focusing light of the fourth wavelength band from the incident light onto the fourth pixel, and further has a fourth focusing point where light of the fourth wavelength band is focused approximately at the center of the fourth pixel, the fourth wavelength focusing region has an area larger than the area of ​​the fourth pixel and extends asymmetrically from the fourth focusing point.

15. The light detection device according to claim 14, wherein the first pixel is a red pixel that detects red light as light in the first wavelength band, the second pixel is a green pixel that detects green light as light in the second wavelength band, the third pixel is a blue pixel that detects blue light as light in the third wavelength band, and the fourth pixel is an IR pixel that detects infrared light as light in the fourth wavelength band, and one red pixel, one green pixel, one blue pixel, and one IR pixel are arranged in 2 rows x 2 columns.

16. The light detection device according to claim 6, further comprising a color filter between the semiconductor substrate and the light guide portion, wherein the color filter includes a first filter that selectively transmits light in the first wavelength band, a second filter that selectively transmits light in the second wavelength band, and a third filter that selectively transmits light in the third wavelength band, the first filter being arranged in the first pixel, the second filter being arranged in the second pixel, and the third filter being arranged in the third pixel.

17. The light guide portion comprises a plurality of structures having a size less than or equal to the wavelength of the incident light, and a medium provided to fill the space between adjacent plurality of structures and having a refractive index different from that of the plurality of structures, according to claim 1.

18. The photodetector according to claim 17, wherein the plurality of structures separate the incident light into light of a plurality of wavelength bands.

19. The light detection device according to claim 1, wherein the light guide portion includes a first light guide portion and a second light guide portion, and the light guide portion and the light guide portion are stacked in the direction of incidence of the light.

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