Photodetector and electronic device

Abstract

The present disclosure pertains to a photodetector and an electronic device that make it possible to more appropriately attenuate incident light and achieve a high dynamic range. The photodetector comprises a high-sensitivity pixel and multiple types of low-sensitivity pixels, wherein: the high-sensitivity pixel and the low-sensitivity pixels each have a photoelectric conversion unit formed on a semiconductor substrate and multiple on-chip lenses formed on the light-incident surface side of the semiconductor substrate; each of the low-sensitivity pixels also has a light attenuation film disposed between the multiple on-chip lenses and the semiconductor substrate; and if each region formed by dividing the region corresponding to one on-chip lens into four equal parts that are symmetrical in the vertical, horizontal and diagonal directions is set as a light-incident unit region and the number of the light-incident regions of each of the high-sensitivity pixel and the multiple types of low-sensitivity pixels are counted in terms of light-incident unit regions, the sums of the light-incident unit regions have a relationship of a prescribed multiple in the high-sensitivity pixel and the multiple types of low-sensitivity pixels. The technology of the present disclosure can be applied, for example, to a photodetector that generates and outputs an imaging signal corresponding to the amount of incident light.

Description

Optical Detection Device and Electronic Device

[0001] The present disclosure relates to an optical detection device and an electronic device, and particularly to an optical detection device and an electronic device capable of more appropriately reducing incident light and realizing a high dynamic range.

[0002] Conventionally, in order to realize the high dynamic range of an image sensor, an optical detection device has been proposed that introduces a light reduction structure that causes a sensitivity difference between pixels. For example, in the optical detection device described in Patent Document 1, a configuration is disclosed in which a mesh-shaped structure in which a mesh-shaped light shielding pattern is formed is arranged as a light reduction structure between an on-chip lens and a photoelectric conversion unit.

[0003] International Publication No. 2024 / 111271

[0004] In the optical detection device described in Patent Document 1, when the mesh-shaped structure is arranged at the same depth position as the inter-pixel light shielding film, the angular responsiveness to incident light, that is, the sensitivity according to the incident angle of light, periodically changes according to the light shielding pattern. Therefore, the mesh-shaped structure is arranged near the on-chip lens. However, when the mesh-shaped structure is arranged near the on-chip lens, there is a concern that the reflected light component becomes flare light.

[0005] The present disclosure has been made in view of such a situation, and is intended to more appropriately reduce incident light and realize a high dynamic range.

[0006] The first aspect of the light detection device of this disclosure comprises a pixel array portion in which a plurality of pixels, including a high-sensitivity pixel having a first sensitivity and a plurality of types of low-sensitivity pixels having a sensitivity lower than the first sensitivity, are arranged in a matrix in a two-dimensional manner, wherein the high-sensitivity pixel and the low-sensitivity pixel each have a photoelectric conversion portion formed on a semiconductor substrate and a plurality of on-chip lenses formed on the light incident surface side of the semiconductor substrate, and the low-sensitivity pixel further has a light-reducing film disposed between the plurality of on-chip lenses and the semiconductor substrate, which blocks a portion of the light incident on the photoelectric conversion portion, and one region obtained by dividing the region corresponding to one of the on-chip lenses into four equal parts so as to be symmetrical in the vertical, horizontal, and diagonal directions is defined as a light incident unit region, and when the number of light incident units of the high-sensitivity pixel and the plurality of types of low-sensitivity pixels is counted by the number of light incident unit regions, the sum of the light incident unit regions of the high-sensitivity pixel and the plurality of types of low-sensitivity pixels is a multiple of a predetermined value.

[0007] The electronic device according to the second aspect of the present disclosure comprises a pixel array portion in which a plurality of pixels, including a high-sensitivity pixel having a first sensitivity and a plurality of types of low-sensitivity pixels having a sensitivity lower than the first sensitivity, are arranged in a matrix in a two-dimensional manner, wherein the high-sensitivity pixel and the low-sensitivity pixel each have a photoelectric conversion portion formed on a semiconductor substrate and a plurality of on-chip lenses formed on the light incident surface side of the semiconductor substrate, and the low-sensitivity pixel further has a light-reducing film disposed between the plurality of on-chip lenses and the semiconductor substrate, which blocks a portion of the light incident on the photoelectric conversion portion, and the photodetector comprises a light detection device in which a region corresponding to one of the on-chip lenses is divided into four equal parts so as to be symmetrical in the vertical, horizontal, and diagonal directions, and one region is defined as a light incident unit region, and when the number of light incident unit regions is counted for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels, the sum of the light incident unit regions is a multiple of a predetermined value for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels.

[0008] In the first and second aspects of this disclosure, a pixel array is provided in which a plurality of pixels, including a high-sensitivity pixel having a first sensitivity and a plurality of types of low-sensitivity pixels having a sensitivity lower than the first sensitivity, are arranged in a matrix in a two-dimensional manner. The high-sensitivity pixel and the low-sensitivity pixel are provided with a photoelectric conversion unit formed on a semiconductor substrate and a plurality of on-chip lenses formed on the light incident surface side of the semiconductor substrate. The low-sensitivity pixel is further provided with a light-reducing film disposed between the plurality of on-chip lenses and the semiconductor substrate, which blocks a portion of the light incident on the photoelectric conversion unit. A region corresponding to one of the on-chip lenses is divided into four equal parts so as to be symmetrical in the vertical, horizontal, and diagonal directions, and one region is defined as a light incident unit region. When the number of light incident unit regions is counted for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels, the sum of the light incident unit regions is configured to be a multiple of a predetermined value for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels.

[0009] The light detection device and electronic equipment may be independent devices or modules incorporated into other devices.

[0010] This figure shows the schematic configuration of a photodetector to which the technology of this disclosure is applied. This figure shows the equivalent circuit of a pixel in the photodetector. This figure shows an example of a cross-sectional configuration of a high-sensitivity pixel in the first embodiment. This is a plan view showing the arrangement of an on-chip lens and a light-shielding film. This is a plan view illustrating the difference in light-shielding structures between high-sensitivity pixels and low-sensitivity pixels. This figure shows an example of a cross-sectional configuration of a low-sensitivity pixel. This is a plan view illustrating the arrangement pattern of the light-reducing film of the first low-sensitivity pixel. This is a plan view illustrating the arrangement pattern of the light-reducing film of the second low-sensitivity pixel. This figure shows an example of a cross-sectional configuration of a second low-sensitivity pixel. This is a plan view illustrating the arrangement pattern of the light-reducing film of the third low-sensitivity pixel. This is a plan view illustrating the configuration of high-sensitivity pixels and low-sensitivity pixels in the second embodiment. This figure shows an example of a cross-sectional configuration of a low-sensitivity pixel. This is a plan view illustrating the configuration of high-sensitivity pixels and low-sensitivity pixels in the third embodiment. This is a plan view illustrating a modified example of a low-sensitivity pixel. This is a cross-sectional view of the low-sensitivity pixel in Figure 14. This is a plan view illustrating the configuration of high-sensitivity pixels and low-sensitivity pixels in the fourth embodiment. This is a plan view illustrating the configuration of high-sensitivity pixels and low-sensitivity pixels in the fourth embodiment. This is a plan view illustrating the configuration of high-sensitivity pixels and low-sensitivity pixels in the fourth embodiment. This is a diagram illustrating an example of the cross-sectional configuration of high-sensitivity pixels in the fourth embodiment. This is a diagram illustrating an example of the cross-sectional configuration of low-sensitivity pixels in Figure 16B. This is a diagram illustrating an example of the cross-sectional configuration of low-sensitivity pixels in Figure 18C. This is a plan view illustrating the configuration of high-sensitivity pixels and low-sensitivity pixels in the fifth embodiment. This is a diagram illustrating the shape of the end face of the light-reducing film in the fifth embodiment. This is a diagram illustrating an example of the cross-sectional configuration of high-sensitivity pixels in the sixth embodiment. This is a diagram illustrating an example of the cross-sectional configuration of high-sensitivity pixels in a modified example of the sixth embodiment. This is a block diagram illustrating an example of the configuration of an electronic device to which the technology of this disclosure is applied. This is a diagram illustrating an example of the use of an image sensor. This is a block diagram illustrating an example of the schematic configuration of a vehicle control system. This is an explanatory diagram showing an example of the installation position of the external information detection unit and the imaging unit.

[0011] The following describes embodiments for carrying out the technology of this disclosure (hereinafter referred to as "embodiments") with reference to the attached drawings. The description will proceed in the following order: 1. Example of overall configuration of a light detection device 2. Equivalent circuit of a pixel 3. Example of pixel configuration of the first embodiment 4. Example of pixel configuration of the second embodiment 5. Example of pixel configuration of the third embodiment 6. Example of pixel configuration of the fourth embodiment 7. Example of pixel configuration of the fifth embodiment 8. Example of pixel configuration of the sixth embodiment 9. Summary of pixel configuration examples 10. Example of configuration of electronic equipment 11. Example of use of an image sensor 12. Example of application to a mobile device

[0012] In this specification and the drawings, identical or similar parts are denoted by the same or similar reference numerals, thereby omitting redundant explanations as appropriate. The drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of the thickness of each layer, etc., may differ from the actual ones. Furthermore, there may be parts where the dimensional relationships and ratios differ between drawings.

[0013] Furthermore, the definitions of directions such as up and down in the following explanation are merely for explanatory convenience and do not limit the technical concept of this disclosure. For example, if an object is rotated 90° and observed, up and down will be converted to left and right and read accordingly, and if it is rotated 180° and observed, up and down will be inverted and read accordingly.

[0014] The technology disclosed herein can be applied to all types of photodetectors having a pixel array in which pixels are arranged two-dimensionally in a matrix, and which convert incident light into photoelectric signals and output a pixel signal corresponding to the amount of light. The light to be detected may be light in the visible light region including wavelengths such as R (Red), G (Green), and B (Blu), or it may be light in the invisible light region such as infrared light. Alternatively, both visible and invisible light regions may be used as the detection target. The photodetector can be used as a solid-state imaging device that generates and outputs an imaging signal corresponding to the amount of incident light, or as a light-receiving device (distance sensor) in a distance measuring system that receives light (reflected light) reflected from an object after infrared light has been irradiated as active light, and measures the distance to the subject using a direct ToF (Time of Flight) or indirect ToF (Time of Flight) method. Below, an example of applying the technology disclosed herein to a photodetector that receives light in the visible light region and generates and outputs an imaging signal corresponding to the amount of incident light will be described.

[0015] <1. Example of overall configuration of a photodetector> Figure 1 shows a schematic configuration of a photodetector to which the technology of this disclosure is applied.

[0016] The photodetector 1 in Figure 1 is constructed on a semiconductor substrate 21 made of, for example, single-crystal silicon (Si) as the semiconductor, and includes a pixel array section 3 and a peripheral circuit region around it. The peripheral circuit region includes a vertical drive circuit 4, a column signal processing circuit 5, a horizontal drive circuit 6, an output circuit 7, a control circuit 8, and the like.

[0017] The pixel array section 3 has a configuration in which pixels 2, each having a photoelectric conversion unit that generates and stores photocharges corresponding to the amount of light received, are arranged in two dimensions in the row and column directions, i.e., in a matrix. Here, the row direction refers to the horizontal arrangement direction of the pixel array section 3, and the column direction refers to the vertical arrangement direction of the pixel array section 3.

[0018] Pixel 2 consists of a photodiode, which is a photoelectric conversion unit, and a plurality of pixel transistors. The plurality of pixel transistors consist of, for example, four transistors: a transfer transistor, a selection transistor, a reset transistor, and an amplification transistor, each of which is a MOS transistor (MOS FET).

[0019] Pixel 2 can also be a shared pixel structure. This shared pixel structure consists of multiple photodiodes, multiple transfer transistors, one shared floating diffusion transistor, and one shared other pixel transistor. In other words, in the shared pixel structure, each pixel 2 has a photodiode and a transfer transistor, and the other pixel transistors are shared and used by multiple pixels 2.

[0020] The control circuit 8 receives the input clock and data that commands the operating mode, and outputs data such as internal information of the light detection device 1. In other words, the control circuit 8 generates clock signals and control signals that serve as the reference for the operation of the vertical drive circuit 4, column signal processing circuit 5, and horizontal drive circuit 6, etc., based on the vertical synchronization signal, horizontal synchronization signal, and master clock. The control circuit 8 then outputs the generated clock signals and control signals to the vertical drive circuit 4, column signal processing circuit 5, and horizontal drive circuit 6, etc.

[0021] The vertical drive circuit 4 is configured, for example, by a shift register, and selects a predetermined pixel drive wiring 10, supplies pulses to the selected pixel drive wiring 10 to drive the pixels 2, and drives the pixels 2 row by row. That is, the vertical drive circuit 4 sequentially selects and scans each pixel 2 of the pixel array 3 row by row in the vertical direction, and supplies a signal based on the signal charge generated in the photoelectric conversion unit of each pixel 2 according to the amount of light received to the column signal processing circuit 5 through the vertical signal line 9.

[0022] The column signal processing circuit 5 is located for each column of pixels 2 and performs signal processing such as noise reduction on the signals output from each row of pixels 2 for each pixel column. For example, the column signal processing circuit 5 performs signal processing such as CDS (Correlated Double Sampling) and AD conversion to remove pixel-specific fixed pattern noise.

[0023] The horizontal drive circuit 6 is composed of, for example, a shift register, and sequentially outputs horizontal scanning pulses to select each of the column signal processing circuits 5 in order, causing each of the column signal processing circuits 5 to output a pixel signal to the horizontal signal line 11.

[0024] The output circuit 7 processes the signals sequentially supplied from each of the column signal processing circuits 5 through the horizontal signal line 11 and outputs them. The output circuit 7 may, for example, only perform buffering, or it may perform black level adjustment, column variation correction, various digital signal processing, etc. The input / output terminal 13 exchanges signals with the outside.

[0025] The light detection device 1 configured as described above has a structure called a column AD method, in which column signal processing circuits 5 that perform CDS processing and AD conversion processing are arranged in each column. The light detection device 1 generates a signal corresponding to the amount of light received by each pixel 2 in the pixel array section 3 and outputs it to the outside. The light detection device 1 can be used, for example, as a solid-state imaging device that detects the distribution of incident light amount of infrared light or visible light and captures it as an image, or as a light receiving device in a distance measuring system that receives light (reflected light) reflected from an object when infrared light is irradiated as active light, and measures the distance to the subject using a direct ToF method or an indirect ToF method.

[0026] <2. Equivalent Circuit of Pixel> Figure 2 shows the equivalent circuit of pixel 2.

[0027] Pixel 2 includes, for example, a photodiode PD as a photoelectric conversion unit, a transfer transistor TG electrically connected to the photodiode PD, and a floating diffusion FD electrically connected to the transfer transistor TG. Pixel 2 also includes a reset transistor RST, an amplification transistor AMP, and a selection transistor SEL. The transfer transistor TG, reset transistor RST, amplification transistor AMP, and selection transistor SEL are composed of, for example, N-type MOS transistors (MOS FETs).

[0028] A photodiode (PD) converts incident light into electricity, generating an electric charge (signal charge) corresponding to the amount of incident light received. In a photodiode (PD), the cathode is electrically connected to the source of a transfer transistor (TG), and the anode is electrically connected to a reference potential line (e.g., ground).

[0029] The transfer transistor TG controls the transfer of charge generated by the photodiode PD. When the transfer transistor TG is turned ON, it transfers the charge generated by the photodiode PD to the floating diffusion FD. In the transfer transistor TG, the drain is electrically connected to the floating diffusion FD, and the gate is electrically connected to the pixel drive wiring. This pixel drive wiring is part of the pixel drive wiring 10 described in Figure 1.

[0030] The floating diffusion transistor (FD) is a charge storage unit that temporarily stores the charge transferred from the photodiode (PD), and also a charge-voltage conversion unit that generates a voltage corresponding to the amount of charge. The floating diffusion transistor (FD) is electrically connected to the gate of the amplification transistor (AMP) and the source of the reset transistor (RST).

[0031] The reset transistor RST resets the potential of the floating diffusion FD to a predetermined potential. When the reset transistor RST is turned on by the pixel drive wiring supplied to the gate, it resets the potential of the floating diffusion FD to the potential of the power line VDD. This pixel drive wiring is part of the pixel drive wiring 10 described in Figure 1. When the potential of the floating diffusion FD is reset, the reset transistor RST is also controlled to be turned on at the same time.

[0032] The amplification transistor AMP generates a signal with a voltage corresponding to the level of charge accumulated in the floating diffusion FD as a pixel signal. The amplification transistor AMP is connected in series with the selection transistor SEL and is connected to the vertical signal line 9 via the selection transistor SEL. This amplification transistor AMP, together with the load circuit in the column signal processing circuit 5 connected to the vertical signal line 9, constitutes a source follower. When the selection transistor SEL is turned on, the amplification transistor AMP outputs the voltage of the floating diffusion FD to the column signal processing circuit 5 via the vertical signal line 9. The drain of the amplification transistor AMP is connected to the power line VDD, and the source of the amplification transistor AMP is connected to the drain of the selection transistor SEL.

[0033] The selection transistor SEL controls the output timing of the pixel signal. The source of the selection transistor SEL is connected to the vertical signal line 9, and the gate of the selection transistor SEL is connected to the pixel drive wiring. When the selection transistor SEL is turned on by the pixel drive wiring supplied to its gate, it outputs the pixel signal from the amplification transistor AMP to the vertical signal line 9. This pixel drive wiring is part of the pixel drive wiring 10 described in Figure 1.

[0034] The selection transistor SEL may be located between the power line VDD and the amplification transistor AMP. In this case, the drain of the reset transistor RST is electrically connected to the power line VDD and the drain of the selection transistor SEL. The source of the selection transistor SEL is electrically connected to the drain of the amplification transistor AMP. The source of the amplification transistor AMP (the output terminal of pixel 2) is electrically connected to the vertical signal line 9, and the gate of the amplification transistor AMP is electrically connected to the source of the reset transistor RST.

[0035] The pixel 2, configured as described above, converts incident light into photoelectric light according to the control of the vertical drive circuit 4 and outputs a pixel signal corresponding to the amount of light received to the column signal processing circuit 5 via the vertical signal line 9.

[0036] The following describes the pixel structure used in pixel 2 of the light detection device 1.

[0037] <3. Pixel Configuration Example of the First Embodiment> The pixels 2 arranged in a matrix in the pixel array section 3 of the light detection device 1 include high-sensitivity pixels 2H having a first sensitivity and low-sensitivity pixels 2L having a second sensitivity lower than the first sensitivity. The high-sensitivity pixels 2H are the pixels among the multiple pixels 2 arranged in two dimensions in the pixel array section 3 that have the smallest light-shielding area and allow the most incident light to enter them, while the low-sensitivity pixels 2L have a larger light-shielding area than the high-sensitivity pixels 2H and are less sensitive than the high-sensitivity pixels 2H. The number of pixels arranged in the pixel array section 3 is, for example, greater for high-sensitivity pixels 2H than for low-sensitivity pixels 2L.

[0038] The light detection device 1 is equipped with high-sensitivity pixels 2H and low-sensitivity pixels 2L in the pixel array section 3, and by acquiring pixel signals with a sensitivity difference, the dynamic range is expanded and high dynamic range is achieved.

[0039] <Example of High-Sensitivity Pixel Configuration> Figure 3 shows an example of a cross-sectional configuration of a high-sensitivity pixel in the first embodiment of the light detection device 1.

[0040] In the following descriptions of high-sensitivity pixels 2H and low-sensitivity pixels 2L, if they are common to both high-sensitivity pixels 2H and low-sensitivity pixels 2L, they may be referred to as "pixel 2".

[0041] In the photodetector 1, a photodiode PD, which serves as a photoelectric conversion unit, is formed on a pixel-by-pixel basis by forming an N-type semiconductor region 42, which is an N-type (second conductivity type) impurity region, in the P-type semiconductor region 41, which is a P-type (first conductivity type) impurity region, for each pixel 2 on the semiconductor substrate 21. The P-type semiconductor region 41 facing both the front and back surfaces of the semiconductor substrate 21 also serves as a hole charge accumulation region for suppressing dark current. The semiconductor substrate 21 is made of, for example, a silicon (Si) substrate.

[0042] Pixel 2 has an insulating film 22, an interlens light-shielding film 23, a color filter layer 24, and an on-chip lens 25 on the light incident surface (hereinafter also referred to as "back surface S1") of the semiconductor substrate 21. On the surface of the semiconductor substrate 21 opposite to the back surface S1 (hereinafter also referred to as "front surface S2"), a wiring layer 31 is formed. The wiring layer 31 has a plurality of pixel transistors Tr (not shown) that perform functions such as reading out the charge accumulated in the photodiode PD, and a plurality of layers of metal wiring 32 and interlayer insulating film 33. Specifically, the pixel transistors Tr are the transfer transistor TG, reset transistor RST, amplification transistor AMP, and selection transistor SEL mentioned above.

[0043] The insulating film 22 on the back surface S1 side of the semiconductor substrate 21, the inter-lens light-shielding film 23, the color filter layer 24, and the on-chip lens 25 are stacked in this order from the back surface S1 of the semiconductor substrate 21.

[0044] The insulating film 22 is made of, for example, silicon oxide (SiO2), silicon nitride (SiN), etc. The insulating film 22 may be composed of, for example, a plurality of insulating films with different refractive indexes, for example, a two-layer film of hafnium oxide (HfO2) film and silicon oxide film, and may be provided with a function as an antireflection film to prevent reflection of incident light. The inter-lens light-shielding film 23 is provided in a grid pattern at the boundary of each on-chip lens 25 in a plan view. The inter-lens light-shielding film 23 may be any material that can shield light, but a material with strong light-shielding property and can be accurately processed by microfabrication, for example, etching, is desirable. The inter-lens light-shielding film 23 can be formed of, for example, a metal film such as tungsten (W), aluminum (Al), copper (Cu), titanium (Ti), molybdenum (Mo), nickel (Ni), etc. The color filter layer 24 is formed by spin-coating a photosensitive resin containing a pigment or a dye such as a dye. As the arrangement of the color filter layer 24, each color of R (red), G (green), and B (blue) is arranged in pixel units, for example, by a Bayer arrangement, but other arrangement methods may also be used.

[0045] A plurality of on-chip lenses 25 are formed so as to be arranged for each pixel, collect light from a subject, and make it incident into the corresponding photodiode PD through the color filter layer 24 and the like. The on-chip lens 25 is formed of, for example, a resin-based material such as a styrene-based resin, an acrylic-based resin, a styrene-acrylic copolymer-based resin, or a siloxane-based resin.

[0046] A in FIG. 4 is a plan view showing the arrangement of the on-chip lens 25 in FIG. 3, and B in FIG. 4 is a plan view showing the arrangement of the inter-lens light-shielding film 23 in FIG. 3.

[0047] As shown in A of FIG. 4, four on-chip lenses 25 consisting of 2x2 are arranged in the pixel 2. The inter-lens light-shielding film 23 is provided in a grid pattern at the boundary of the four on-chip lenses 25 consisting of 2x2 as shown in B of FIG. 4.

[0048] In addition, in A and B of FIG. 4, the dividing lines that divide pixel 2 into 2x2, specifically the central solid line that bisects pixel 2 in the column and row directions, are auxiliary lines for explaining that the on-chip lens 25 is formed in a 2x2 arrangement. Such boundary lines are not provided in the actual pixel 2 of the light detection device 1.

[0049] The high-sensitivity pixel 2H in the first embodiment has the above configuration.

[0050] <Configuration Example of Low-Sensitivity Pixel> Next, the configuration of the low-sensitivity pixel 2L will be described while comparing it with the high-sensitivity pixel 2H.

[0051] FIG. 5 is a plan view for explaining the difference in the light shielding structure between the high-sensitivity pixel 2H and the low-sensitivity pixel 2L.

[0052] A in FIG. 5 is a plan view of the high-sensitivity pixel 2H, and B to D in FIG. 5 are plan views of the low-sensitivity pixel 2L.

[0053] In the low-sensitivity pixel 2L, a light attenuation film 23X is formed between the on-chip lens 25 and the semiconductor substrate 21. The light attenuation film 23X is a film that shields a part of the light incident on the photodiode PD. The light attenuation film 23X is formed of the same material as the inter-lens light shielding film 23 described for the high-sensitivity pixel 2H, for example, and at the same time. There are three types of low-sensitivity pixels 2L, namely 2La to 2Lc. The low-sensitivity pixels 2La to 2Lc have different degrees of light attenuation for the incident light, that is, different sensitivities, due to the different regions of the light attenuation film 23X arranged. The low-sensitivity pixel 2La is the first low-sensitivity pixel, the low-sensitivity pixel 2Lb is the second low-sensitivity pixel with a lower sensitivity than the first low-sensitivity pixel, and the low-sensitivity pixel 2Lc is the third low-sensitivity pixel with a lower sensitivity than the second low-sensitivity pixel. The plan views of A to D in FIG. 5 show the plan views of the on-chip lens 25 and the light attenuation film 23X, and the illustration of the inter-lens light shielding film 23 commonly provided in the high-sensitivity pixel 2H and the low-sensitivity pixel 2L is omitted.

[0054] A light incidence unit region OCLB1 is set as a region for comparing the amount of incident light incident on the photodiode PD and the amount of light blocked by the light-reducing film 23X in the high-sensitivity pixel 2H and the low-sensitivity pixel 2L. As shown in Figure 5A, the light incidence unit region OCLB1 corresponds to one region (1 / 16 pixel region) obtained by dividing a 1 / 4 pixel region corresponding to one on-chip lens 25 into four equal parts symmetrically in the vertical, horizontal, and diagonal directions.

[0055] If the amount of incident light incident on the high-sensitivity pixel 2H is taken as "1" (100%), then the amount of incident light incident on the low-sensitivity pixel 2La is "3 / 4" (75%), the amount of incident light incident on the low-sensitivity pixel 2Lb is "2 / 4" (50%), and the amount of incident light incident on the low-sensitivity pixel 2Lc is "1 / 4" (25%). More specifically, since the light-reducing film 23X is not placed on the high-sensitivity pixel 2H, the region where incident light is incident on the high-sensitivity pixel 2H consists of 16 light-incident unit regions OCLB1. The light-reducing film 23X is placed on a 1 / 4 pixel region corresponding to one on-chip lens 25 in the low-sensitivity pixel 2La. Therefore, the region where incident light is incident on the low-sensitivity pixel 2La consists of 12 light-incident unit regions OCLB1. The light-reducing film 23X is placed on a 2 / 4 pixel region corresponding to two on-chip lenses 25 in the low-sensitivity pixel 2Lb. Therefore, in the low-sensitivity pixel 2Lb, the region into which incident light is incident consists of eight light-incident unit regions OCLB1. In the low-sensitivity pixel 2Lc, a light-reducing film 23X is placed in 3 / 4 pixel regions corresponding to three on-chip lenses 25. Therefore, in the low-sensitivity pixel 2Lc, the region into which incident light is incident consists of four light-incident unit regions OCLB1.

[0056] The light-incident regions of the high-sensitivity pixel 2H and the low-sensitivity pixel 2L are provided with a light-reducing film 23X such that the sum of the number of light-incident unit regions OCLB1 is a multiple of "4". Here, "4" corresponds to the number of light-incident unit regions OCLB1 of the lowest-sensitivity pixel 2Lc. Specifically, the light-incident region of the lowest-sensitivity pixel 2Lc has 4 light-incident unit regions OCLB1, the light-incident region of the next lowest-sensitivity pixel 2Lb has 8 light-incident unit regions OCLB1, the light-incident region of the next lowest-sensitivity pixel 2La has 12 light-incident unit regions OCLB1, and the light-incident region of the high-sensitivity pixel 2H has 16 light-incident unit regions OCLB1. In this way, by providing the light-incident regions of the high-sensitivity pixel 2H and the low-sensitivity pixels 2La to 2Lc with a light-reducing film 23X such that the sum of the number of light-incident unit regions OCLB1 is a multiple of "4", it is possible to construct light-reducing pixels with a desired sensitivity difference relative to the high-sensitivity pixel 2H.

[0057] Figure 6 shows an example of the cross-sectional configuration of the low-sensitivity pixel 2La in the X-X' line of Figure 5B.

[0058] In the low-sensitivity pixel 2La, as shown in Figure 6, the light-reducing film 23X is formed in the same layer as the inter-lens light-shielding film 23. In the example in Figure 6, the thickness (film thickness) of the light-reducing film 23X is thinner than that of the inter-lens light-shielding film 23, but it may also be the same thickness as the inter-lens light-shielding film 23. In the low-sensitivity pixel 2La, other than the presence or absence of the light-reducing film 23X, it is the same as the high-sensitivity pixel 2H, so further explanation is omitted.

[0059] In the low-sensitivity pixel 2La shown in Figure 5B, a light-reducing film 23X was formed on the lower right portion of the four on-chip lenses 25, which are arranged in a 2x2 configuration. However, the region on which the light-reducing film 23X is formed is not limited to the lower right portion of the 2x2 on-chip lenses 25.

[0060] Figure 7 is a plan view showing an example of the arrangement of the light-reducing film 23X in the low-sensitivity pixel 2La.

[0061] There are four types of low-sensitivity pixels 2La arranged in the pixel array section 3, as shown in Figures 7A to D, which differ in the arrangement of the light-reducing film 23X. The same number of these four types of low-sensitivity pixels 2La shown in Figures 7A to D are arranged in the pixel array section 3. This maintains symmetry in the vertical, horizontal, and diagonal directions within the pixel array section 3.

[0062] Figure 8 is a plan view showing an example of the arrangement of the light-reducing film 23X in a low-sensitivity pixel 2Lb.

[0063] Low-sensitivity pixels 2Lb, which have 2 / 4 the sensitivity of high-sensitivity pixels 2H, exist in two types, A and B in Figure 8, with different arrangements of the light-reducing film 23X. The X-X' and Y-Y' cross-sectional views of Figure 8A are the same as in Figure 6, and the Z-Z' cross-sectional view of Figure 8A is as shown in Figure 9. The two types of low-sensitivity pixels 2Lb in Figure 8 are arranged in equal numbers in the pixel array 3. This maintains symmetry in the vertical, horizontal, and diagonal directions in the pixel array 3.

[0064] Figure 10 is a plan view showing an example of the arrangement of the light-reducing film 23X in a low-sensitivity pixel 2Lc.

[0065] The low-sensitivity pixels 2Lc, which have 1 / 4 the sensitivity of the high-sensitivity pixels 2H, come in four types, A to D in Figure 10, each with a different arrangement of the light-reducing film 23X. The four types of low-sensitivity pixels 2Lc in Figure 10 are arranged in equal numbers in the pixel array section 3. This maintains symmetry in the vertical, horizontal, and diagonal directions within the pixel array section 3.

[0066] As described above, the low-sensitivity pixels 2La to 2Lc can maintain symmetry in the vertical, horizontal, and diagonal directions within the pixel array 3, making it possible to attenuate light while maintaining as much angular responsiveness to incident light as possible. Furthermore, since the area of ​​the photoelectric conversion region is not affected by the design of the light-gathering focus position, the design offers greater flexibility, as the high-sensitivity pixels 2H and low-sensitivity pixels 2L do not affect the design of the photoelectric conversion region.

[0067] In the low-sensitivity pixels 2La to 2Lc, the on-chip lens 25 is not required to be formed in the region where the light-reducing film 23X is located. However, forming the on-chip lens 25 maintains the periodicity of the lens shape, thus simplifying the manufacturing process.

[0068] <4. Pixel Configuration Example of the Second Embodiment> Next, the configuration of high-sensitivity pixels and low-sensitivity pixels in the second embodiment of the light detection device 1 will be described.

[0069] Figure 11 is a plan view illustrating the configuration of the high-sensitivity pixel 2H and low-sensitivity pixel 2L in the second embodiment. In Figure 11, as in Figure 5, a plan view of the on-chip lens 25 and the light-reducing film 23Y is shown.

[0070] In the second embodiment, the high-sensitivity pixel 2H is the same as in the first embodiment described above. In the low-sensitivity pixel 2L, a light-reducing film 23Y is formed instead of the light-reducing film 23X of the first embodiment described above, and the arrangement of the light-reducing film 23Y within the pixel is different from that of the light-reducing film 23X of the first embodiment. There are three types of low-sensitivity pixels 2L, 2La to 2Lc, and the degree of light reduction that reduces incident light, i.e., sensitivity, differs among the low-sensitivity pixels 2La to 2Lc due to the different regions in which the light-reducing film 23Y is arranged.

[0071] In the second embodiment as well, if the amount of incident light incident on the high-sensitivity pixel 2H is "1", the amount of incident light incident on the low-sensitivity pixel 2La is "3 / 4", the amount of incident light incident on the low-sensitivity pixel 2Lb is "2 / 4", and the amount of incident light incident on the low-sensitivity pixel 2Lc is "1 / 4". More specifically, since the light-reducing film 23Y is not placed on the high-sensitivity pixel 2H, the region to which incident light is incident on the high-sensitivity pixel 2H consists of 16 light-incident unit regions OCLB1. The light-reducing film 23Y is placed on a 1 / 4 pixel region corresponding to one on-chip lens 25 in the low-sensitivity pixel 2La. Therefore, the region to which incident light is incident on the low-sensitivity pixel 2La consists of 12 light-incident unit regions OCLB1. The light-reducing film 23Y is placed on a 2 / 4 pixel region corresponding to two on-chip lenses 25 in the low-sensitivity pixel 2Lb. Therefore, the region to which incident light is incident on the low-sensitivity pixel 2Lb consists of 8 light-incident unit regions OCLB1. In the low-sensitivity pixel 2Lc, a light-reducing film 23Y is placed in a 3 / 4 pixel area corresponding to three on-chip lenses 25. Therefore, the area into which incident light is incident in the low-sensitivity pixel 2Lc consists of four light-incident unit regions OCLB1.

[0072] The light-incident regions of the high-sensitivity pixel 2H and the low-sensitivity pixel 2L are provided with a light-reducing film 23Y such that the sum of the number of light-incident unit regions OCLB1 is a multiple of "4". Here, "4" corresponds to the number of light-incident unit regions OCLB1 of the lowest-sensitivity pixel 2Lc. Specifically, the light-incident region of the lowest-sensitivity pixel 2Lc has 4 light-incident unit regions OCLB1, the light-incident region of the next lowest-sensitivity pixel 2Lb has 8 light-incident unit regions OCLB1, the light-incident region of the next lowest-sensitivity pixel 2La has 12 light-incident unit regions OCLB1, and the light-incident region of the high-sensitivity pixel 2H has 16 light-incident unit regions OCLB1. In this way, by providing the light-incident regions of the high-sensitivity pixel 2H and the low-sensitivity pixels 2La to 2Lc with a light-reducing film 23Y such that the sum of the number of light-incident unit regions OCLB1 is a multiple of "4", it is possible to construct light-reducing pixels with a desired sensitivity difference relative to the high-sensitivity pixel 2H. In the second embodiment, the arrangement of the light-reducing films 23Y for the low-sensitivity pixels 2La to 2Lc is symmetrical in the diagonal directions (up, down, left, right, and right) within the pixel.

[0073] The cross-sectional views along the X-X' line in Figure 11B, the Y-Y' line in Figure 11C, or the Z-Z' line in Figure 11D are shown in Figure 12.

[0074] In comparison with the first embodiment, the first embodiment requires the placement of ten different arrangement patterns of the light-reducing film 23X within the pixel array 3, with four types shown in Figure 7, two types in Figure 8, and four types in Figure 10. In contrast, the second embodiment has only three arrangement patterns for the light-reducing film 23Y of the low-sensitivity pixels 2L, as shown in Figures 11 (B to D), thus reducing the number of pixel patterns for the low-sensitivity pixels 2L. Furthermore, since the arrangement of the light-reducing film 23Y of the low-sensitivity pixels 2La to 2Lc in the second embodiment is symmetrical in the diagonal directions (up, down, left, right, and right) within the pixel, optical symmetry can be improved.

[0075] According to the second embodiment, it is possible to configure attenuation pixels with a desired sensitivity difference from the high-sensitivity pixels 2H using low-sensitivity pixels 2La to 2Lc, and since symmetry in the vertical, horizontal, and diagonal directions can be maintained within the pixel, it is possible to attenuate light while maintaining angular responsiveness to incident light as much as possible. Furthermore, since the area of ​​the photoelectric conversion region is not changed between the high-sensitivity pixels 2H and the low-sensitivity pixels 2L, and the design is not dependent on the design of the light-gathering focal position, it is possible to have a degree of design freedom.

[0076] <5. Pixel Configuration Example of the Third Embodiment> Next, the configuration of high-sensitivity pixels and low-sensitivity pixels in the third embodiment of the light detection device 1 will be described.

[0077] Figure 13 is a plan view illustrating the configuration of the high-sensitivity pixel 2H and low-sensitivity pixel 2L in the third embodiment. Similar to Figure 5, Figure 13 also shows a plan view of the on-chip lens 25 and the light-reducing film 23Y.

[0078] In the third embodiment, the high-sensitivity pixels 2H are the same as in the first embodiment described above. For the low-sensitivity pixels 2La to 2Lc, the same light-reducing film 23Y as in the second embodiment is formed, but the arrangement of the light-reducing film 23Y within the pixels differs from that of the second embodiment. For the low-sensitivity pixels 2Lc, two types of low-sensitivity pixels 2Lc with different arrangements of the light-reducing film 23Y are arranged in the same number in the pixel array 3.

[0079] In the third embodiment, if the amount of incident light incident on the high-sensitivity pixel 2H is "1", the amount of incident light incident on the low-sensitivity pixel 2La is "3 / 4", the amount of incident light incident on the low-sensitivity pixel 2Lb is "2 / 4", and the amount of incident light incident on the low-sensitivity pixel 2Lc is "1 / 4". More specifically, since the light-reducing film 23Y is not placed on the high-sensitivity pixel 2H, the region to which incident light is incident on the high-sensitivity pixel 2H consists of 16 light-incident unit regions OCLB1. The light-reducing film 23Y is placed on a 1 / 4 pixel region corresponding to one on-chip lens 25 in the low-sensitivity pixel 2La. Therefore, the region to which incident light is incident on the low-sensitivity pixel 2La consists of 12 light-incident unit regions OCLB1. The light-reducing film 23Y is placed on a 2 / 4 pixel region corresponding to two on-chip lenses 25 in the low-sensitivity pixel 2Lb. Therefore, the region to which incident light is incident on the low-sensitivity pixel 2Lb consists of 8 light-incident unit regions OCLB1. In the low-sensitivity pixel 2Lc, a light-reducing film 23Y is placed in a 3 / 4 pixel area corresponding to three on-chip lenses 25. Therefore, the area into which incident light is incident in the low-sensitivity pixel 2Lc consists of four light-incident unit regions OCLB1.

[0080] The light-incident regions of the high-sensitivity pixel 2H and the low-sensitivity pixel 2L are provided with a light-reducing film 23Y such that the sum of the number of light-incident unit regions OCLB1 is a multiple of "4". Here, "4" corresponds to the number of light-incident unit regions OCLB1 of the lowest-sensitivity pixel 2Lc. Specifically, the light-incident region of the lowest-sensitivity pixel 2Lc has 4 light-incident unit regions OCLB1, the light-incident region of the next lowest-sensitivity pixel 2Lb has 8 light-incident unit regions OCLB1, the light-incident region of the next lowest-sensitivity pixel 2La has 12 light-incident unit regions OCLB1, and the light-incident region of the high-sensitivity pixel 2H has 16 light-incident unit regions OCLB1. In this way, by providing the light-incident regions of the high-sensitivity pixel 2H and the low-sensitivity pixels 2La to 2Lc with a light-reducing film 23Y such that the sum of the number of light-incident unit regions OCLB1 is a multiple of "4", it is possible to construct light-reducing pixels with a desired sensitivity difference relative to the high-sensitivity pixel 2H. In the second embodiment, the arrangement of the light-reducing films 23Y for the low-sensitivity pixels 2La to 2Lb is symmetrical in the diagonal directions (up, down, left, right, and right) within the pixel.

[0081] According to the third embodiment, it is possible to configure attenuating pixels with a desired sensitivity difference from the high-sensitivity pixels 2H using low-sensitivity pixels 2La to 2Lc, and since symmetry in the vertical, horizontal, and diagonal directions can be maintained within the pixels or in the pixel array 3, it is possible to attenuate light while maintaining angular responsiveness to incident light as much as possible. Furthermore, since the area of ​​the photoelectric conversion region is not changed between the high-sensitivity pixels 2H and the low-sensitivity pixels 2L, and the design is not dependent on the design of the light-gathering focus position, it is possible to have a degree of design freedom.

[0082] In comparison with the first embodiment, the first embodiment requires 10 types of low-sensitivity pixels 2L with different arrangement patterns of the light-reducing film 23X to be arranged within the pixel array 3. In contrast, the third embodiment has only four types of arrangement patterns for the light-reducing film 23Y of the low-sensitivity pixels 2L, as shown in Figure 12 B to D, thus reducing the number of pixel patterns for the low-sensitivity pixels 2L. Furthermore, in the third embodiment, the low-sensitivity pixels 2La and 2Lb have symmetrical arrangements of the light-reducing film 23Y in the diagonal directions (up, down, left, right, and right) within the pixel, thus improving optical symmetry.

[0083] <Modification> In the second and third embodiments described above, at least a portion of the low-sensitivity pixels 2Lb arranged in the pixel array 3 may be replaced with the four types of low-sensitivity pixels 2Lb shown in Figure 14. The four types of low-sensitivity pixels 2Lb shown in Figure 14 are arranged such that the light-reducing film 23Y blocks light from one of the regions that are divided into two parts horizontally or vertically with respect to the on-chip lens 25. Since these four types of low-sensitivity pixels 2Lb can output a phase difference signal for detecting a phase difference as a pixel signal, they can be used as both a phase difference pixel for detecting a phase difference and a low-sensitivity pixel with "2 / 4" the amount of incident light compared to the high-sensitivity pixel 2H.

[0084] Figure 15 is a cross-sectional view taken along the line X-X' or Y-Y' in Figure 14.

[0085] Furthermore, instead of replacing at least a portion of the low-sensitivity pixels 2Lb in the second and third embodiments, for low-sensitivity pixels with an incident light amount of "2 / 4" that of the high-sensitivity pixels 2H, multiple instances of only the four types of low-sensitivity pixels 2Lb shown in Figure 14 may be arranged. Moreover, a configuration in which only the high-sensitivity pixels 2H and the four types of low-sensitivity pixels 2Lb shown in Figure 14 are arranged in the pixel array section 3 is also acceptable.

[0086] <6. Pixel Configuration Example of the Fourth Embodiment> Next, the configuration of high-sensitivity pixels and low-sensitivity pixels in the fourth embodiment of the light detection device 1 will be described.

[0087] In the fourth embodiment, high-sensitivity pixels 2H' and low-sensitivity pixels 2L' are arranged in the pixel array section 3. There are eight types of low-sensitivity pixels 2L', ranging from 2La' to 2Lh', and these low-sensitivity pixels differ in the degree of light reduction they exert on incident light, i.e., their sensitivity.

[0088] Figures 16 to 18 are plan views illustrating the configuration of the high-sensitivity pixel 2H' and low-sensitivity pixel 2L' in the fourth embodiment. Figures 16 to 18 show plan views of the on-chip lens 25 and the light-reducing film 23Z.

[0089] In the fourth embodiment, the high-sensitivity pixel 2H' shown in Figure 16A has nine on-chip lenses 25 arranged in a 3x3 configuration. A light-reducing film 23Z is formed between the on-chip lens 25 and the semiconductor substrate 21 for the low-sensitivity pixels 2La' in Figure 16B to C in Figure 18. The light-reducing film 23Z is a light-reducing light-shielding film that is formed simultaneously with the inter-lens light-shielding film 23 using the same material. The inter-lens light-shielding film 23 is provided in a grid pattern at the boundaries of the nine on-chip lenses 25 arranged in a 3x3 configuration, as shown in the cross-sectional view of Figure 19, but is omitted from the plan views of Figures 16 to 18 because it is common to both the high-sensitivity pixel 2H' and the low-sensitivity pixel 2L'.

[0090] In the fourth embodiment, the light incident unit region OCLB2 for comparing the amount of incident light and the amount of blocked light in the high-sensitivity pixel 2H and the low-sensitivity pixel 2L is a single region (1 / 36 pixel region) obtained by dividing a 1 / 9 pixel region corresponding to one on-chip lens 25 into four equal parts so as to be symmetrical in the vertical, horizontal, and diagonal directions, as shown in Figure 16A.

[0091] If the amount of incident light incident on the high-sensitivity pixel 2H' in Figure 16A is "1", then the amount of incident light incident on the low-sensitivity pixel 2La' in Figure 16B is "8 / 9", and the amount of incident light incident on the low-sensitivity pixel 2Lb' in Figure 18C is "7 / 9". More specifically, since the light-reducing film 23Z is not placed in the high-sensitivity pixel 2H, the region where incident light is incident on the high-sensitivity pixel 2H consists of 36 light-incident unit regions OCLB2. In the low-sensitivity pixel 2La', the light-reducing film 23Z is placed in a 1 / 9 pixel region corresponding to one on-chip lens 25. Therefore, the region where incident light is incident on the low-sensitivity pixel 2La' consists of 32 light-incident unit regions OCLB2. The arrangement of the light-reducing film 23Z in the low-sensitivity pixel 2La' is symmetrical in the vertical, horizontal, and diagonal directions. In the low-sensitivity pixel 2Lb', the light-reducing film 23Z is placed in a 2 / 9 pixel region corresponding to two on-chip lenses 25. Therefore, the region into which incident light is incident in the low-sensitivity pixel 2Lb' consists of 28 light-incident unit regions OCLB2. The arrangement of the light-reducing film 23Z within the low-sensitivity pixel 2Lb' is symmetrical in the diagonal direction.

[0092] If the amount of incident light incident on the high-sensitivity pixel 2H' in Figure 16A is "1", then the amount of incident light incident on the low-sensitivity pixel 2Lc' in Figure 17A is "6 / 9", the amount of incident light incident on the low-sensitivity pixel 2Ld' in Figure 17B is "5 / 9", and the amount of incident light incident on the low-sensitivity pixel 2Le' in Figure 17C is "4 / 9". More specifically, in the low-sensitivity pixel 2Lc', the light-reducing film 23Z is arranged in a 3 / 9 pixel area corresponding to three on-chip lenses 25. Therefore, the area where incident light is incident on the low-sensitivity pixel 2Lc' consists of 24 light-incident unit areas OCLB2. The arrangement of the light-reducing film 23Z in the low-sensitivity pixel 2Lc' is symmetrical in the vertical, horizontal, and diagonal directions. In the low-sensitivity pixel 2Ld', the light-reducing film 23Z is arranged in a 4 / 9 pixel area corresponding to four on-chip lenses 25. Therefore, the region to which incident light is incident in the low-sensitivity pixel 2Ld' consists of 20 light-incident unit regions OCLB2. The arrangement of the light-reducing film 23Z within the low-sensitivity pixel 2Ld' is diagonally symmetrical. In the low-sensitivity pixel 2Le', the light-reducing film 23Z is arranged in 5 / 9 pixel regions corresponding to 5 on-chip lenses 25. Therefore, the region to which incident light is incident in the low-sensitivity pixel 2Le' consists of 16 light-incident unit regions OCLB2. The arrangement of the light-reducing film 23Z within the low-sensitivity pixel 2Le' is symmetrical in the up, down, left, right, and diagonal directions.

[0093] If the amount of incident light incident on the high-sensitivity pixel 2H' in Figure 16A is "1", then the amount of incident light incident on the low-sensitivity pixel 2Lf' in Figure 18A is "3 / 9", the amount of incident light incident on the low-sensitivity pixel 2Lg' in Figure 18B is "2 / 9", and the amount of incident light incident on the low-sensitivity pixel 2Lh' in Figure 18C is "1 / 9". More specifically, in the low-sensitivity pixel 2Lf', the light-reducing film 23Z is arranged in a 6 / 9 pixel area corresponding to the six on-chip lenses 25. Therefore, the area where incident light is incident on the low-sensitivity pixel 2Lf' consists of 12 light-incident unit areas OCLB2. The arrangement of the light-reducing film 23Z in the low-sensitivity pixel 2Lf' is symmetrical in the vertical, horizontal, and diagonal directions. In the low-sensitivity pixel 2Lg', the light-reducing film 23Z is arranged in a 7 / 9 pixel area corresponding to the seven on-chip lenses 25. Therefore, in the low-sensitivity pixel 2Lg', the region into which incident light is incident consists of eight light-incident unit regions OCLB2. The arrangement of the light-reducing film 23Z within the low-sensitivity pixel 2Lg' is diagonally symmetrical. In the low-sensitivity pixel 2Lh', the light-reducing film 23Z is arranged in 8 / 9 pixel regions corresponding to eight on-chip lenses 25. Therefore, in the low-sensitivity pixel 2Lh', the region into which incident light is incident consists of four light-incident unit regions OCLB2. The arrangement of the light-reducing film 23Z within the low-sensitivity pixel 2Lh' is symmetrical in the up, down, left, right, and diagonal directions.

[0094] Therefore, in the fourth embodiment as well, the light incidence regions of the high-sensitivity pixels 2H' and low-sensitivity pixels 2L' are provided with a light-reducing film 23Z such that the sum of the number of light incidence unit regions OCLB1 is a multiple of "4". Here, "4" corresponds to the number of light incidence unit regions OCLB2 of the lowest-sensitivity pixels 2Lh'. Specifically, the light incident region of the least sensitive pixel 2Lh' has 4 light incident unit regions OCLB2, the next least sensitive pixel 2Lg' has 8 light incident unit regions OCLB2, the next least sensitive pixel 2Lf' has 12 light incident unit regions OCLB2, the next least sensitive pixel 2Le' has 16 light incident unit regions OCLB2, the next least sensitive pixel 2Ld' has 20 light incident unit regions OCLB2, the next least sensitive pixel 2Lc' has 24 light incident unit regions OCLB2, the next least sensitive pixel 2Lb' has 28 light incident unit regions OCLB2, the next least sensitive pixel 2La' has 32 light incident unit regions OCLB2, and the light incident region of the most sensitive pixel 2H' has 36 light incident unit regions OCLB2.

[0095] Figure 19 shows a cross-sectional view of the high-sensitivity pixel 2H' in Figure 16A. Since the high-sensitivity pixel 2H' has nine on-chip lenses 25 arranged in a 3x3 grid, in a cross-sectional view along a line segment that bisects the high-sensitivity pixel 2H' horizontally or vertically, three on-chip lenses 25 are arranged as shown in Figure 19. On the back surface S1 side of the semiconductor substrate 21, a light-shielding film 23 between lenses is provided in a grid pattern at the boundaries of the on-chip lenses 25. The other configurations are the same as in the first embodiment described above.

[0096] Figure 20 shows a cross-sectional view of the low-sensitivity pixel 2La' in Figure 16B along the X-X' line. Similarly, the cross-sectional view of the low-sensitivity pixel 2Ld' in Figure 17B along the Z-Z' line is the same as that of Figure 20. Figure 21 shows a cross-sectional view of the low-sensitivity pixel 2Lh' in Figure 18C along the Y-Y' line.

[0097] According to the fourth embodiment, by providing a light-reducing film 23Z such that the number of light-incident unit regions OCLB1 in the light-incident regions of the high-sensitivity pixel 2H' and the low-sensitivity pixels 2La' to 2Lh' is a multiple of "4", it is possible to configure light-reducing pixels with a desired sensitivity difference relative to the high-sensitivity pixel 2H'. Furthermore, since symmetry in the vertical, horizontal, and diagonal directions can be maintained within the pixel or in the pixel array 3, it is possible to reduce light while maintaining angular responsiveness to incident light as much as possible. In addition, since the area of ​​the photoelectric conversion region is not changed for the high-sensitivity pixel 2H' and the low-sensitivity pixel 2L', and the design is not dependent on the design of the light-collecting focus position, it is possible to have a degree of design freedom.

[0098] In comparison with the first to third embodiments described above, the fourth embodiment allows for an increase in the number of types of pixels 2 that have different sensitivities by arranging nine on-chip lenses 25 in a 3x3 configuration in one pixel, thereby further improving the resolution.

[0099] <7. Pixel Configuration Example of the Fifth Embodiment> Next, the configuration of high-sensitivity pixels and low-sensitivity pixels in the fifth embodiment of the light detection device 1 will be described.

[0100] In the fifth embodiment, high-sensitivity pixels 2H' and low-sensitivity pixels 2L' are arranged in the pixel array section 3. There are three types of low-sensitivity pixels 2L', namely 2La' to 2Lc', and these low-sensitivity pixels 2La' to 2Lc' differ in the degree of light attenuation they exert on incident light, i.e., their sensitivity.

[0101] Figure 22 is a plan view illustrating the configuration of the high-sensitivity pixel 2H' and low-sensitivity pixel 2L' in the fifth embodiment. Figure 22 shows a plan view of the on-chip lens 25 and the light-reducing film 23Z.

[0102] The high-sensitivity pixel 2H' shown in Figure 22A is the same as the high-sensitivity pixel 2H' of the fourth embodiment described above. The high-sensitivity pixel 2H' is equipped with nine on-chip lenses 25 arranged in a 3x3 grid.

[0103] In Figure 22, from low-sensitivity pixel 2La' (B) to low-sensitivity pixel 2Lc' (D), a light-reducing film 23Z is formed between the on-chip lens 25 and the semiconductor substrate 21. The light-reducing film 23Z in the fifth embodiment has a different planar shape from the light-reducing film 23Z in the fourth embodiment described above. In the fifth embodiment, the light-reducing film 23Z is positioned such that the boundary line between the light-reducing region and the light-incident region is at a 45-degree angle to the horizontal or vertical direction of the pixel array 3.

[0104] In the fourth embodiment, if the amount of incident light incident on the high-sensitivity pixel 2H' is "1", then the amount of incident light incident on the low-sensitivity pixel 2La' is "7 / 9", the amount of incident light incident on the low-sensitivity pixel 2Lb' is "3 / 9", and the amount of incident light incident on the low-sensitivity pixel 2Lc' is "2 / 9". More specifically, since no light-reducing film 23Z is placed in the high-sensitivity pixel 2H', the region to which incident light is incident in the high-sensitivity pixel 2H' consists of 36 light-incident unit regions OCLB2. In the low-sensitivity pixel 2La', the light-reducing film 23Z is placed in 6 / 9 pixel regions corresponding to 6 on-chip lenses 25. Therefore, the region to which incident light is incident in the low-sensitivity pixel 2La' consists of 12 light-incident unit regions OCLB2. The arrangement of the light-reducing film 23Z in the low-sensitivity pixel 2La' is symmetrical in the vertical, horizontal, and diagonal directions. In the low-sensitivity pixel 2Lb', the light-reducing film 23Z is placed in 3 / 9 pixel regions corresponding to 3 on-chip lenses 25. Therefore, the region to which incident light is incident in the low-sensitivity pixel 2Lb' consists of 12 light-incident unit regions OCLB1. The arrangement of the light-reducing film 23Z within the low-sensitivity pixel 2Lb' is symmetrical in the vertical, horizontal, and diagonal directions. In the low-sensitivity pixel 2Lc', the light-reducing film 23Y is arranged in 7 / 9 pixel regions corresponding to 7 on-chip lenses 25. Therefore, the region to which incident light is incident in the low-sensitivity pixel 2Lc' consists of 8 light-incident unit regions OCLB1. The arrangement of the light-reducing film 23Z within the low-sensitivity pixel 2Lc' is symmetrical in the vertical, horizontal, and diagonal directions.

[0105] In the fifth embodiment configured as described above, the light incidence regions of the high-sensitivity pixels 2H' and low-sensitivity pixels 2L' are provided with a light-reducing film 23Z such that the sum of the number of light incidence unit regions OCLB1 is a multiple of "4". Specifically, the light incidence region of the lowest-sensitivity pixel 2Lc' has 8 light incidence unit regions OCLB2, the next lowest-sensitivity pixel 2Lb' has 12 light incidence unit regions OCLB2, the next lowest-sensitivity pixel 2La' has 28 light incidence unit regions OCLB2, and the light incidence region of the high-sensitivity pixel 2H' has 36 light incidence unit regions OCLB2. It is possible to configure light-reducing pixels with a desired sensitivity difference from the high-sensitivity pixel 2H' using the low-sensitivity pixels 2La' to 2Lc', and since symmetry in the up, down, left, right, and diagonal directions can be maintained, it is possible to reduce light while maintaining angular responsiveness to incident light as much as possible. Furthermore, because the area of ​​the photoelectric conversion region can be changed using the high-sensitivity pixel 2H' and the low-sensitivity pixel 2L', and the design is not dependent on the design of the light-gathering focus position, it is possible to have a high degree of design flexibility.

[0106] Figure 23 illustrates the shape of the end face of the light-reducing film 23Z.

[0107] As described above, in the fifth embodiment, the boundary line between the light-reducing region and the light-incident region due to the light-reducing film 23Z is oblique to the horizontal or vertical direction of the pixel array 3 at a 45-degree angle. The upper surface of the end face of the light-reducing film 23Z, which forms the boundary line between the light-reducing region and the light-incident region, can be made into an uneven shape, as shown in Figure 23. This suppresses light leakage to surrounding pixels and reduces color mixing by causing diffuse reflection of incident light at the end face of the light-reducing film 23Z. Figure 23 is a plan view of the low-sensitivity pixel 2La', but the same applies to the end faces of the light-reducing film 23Z of the low-sensitivity pixels 2Lb' and 2Lc'.

[0108] <8. Pixel Configuration Example of the Sixth Embodiment> Next, the configuration of high-sensitivity pixels and low-sensitivity pixels in the sixth embodiment of the light detection device 1 will be described. <Example of High-Sensitivity Pixel Configuration> Figure 24 is a diagram showing an example of the cross-sectional configuration of a high-sensitivity pixel in the sixth embodiment.

[0109] The high-sensitivity pixel 2H in the sixth embodiment has a configuration that further includes the same number of inner lenses 72 as the on-chip lens 25 in addition to the pixel structure of the high-sensitivity pixel 2H of the first embodiment shown in Figure 3. Specifically, a first planarization film 71, an inner lens 72, and a second planarization film 73 are stacked between the insulating film 22 and the inter-lens light-shielding film 23 formed on the back surface S1 side of the semiconductor substrate 21 and the color filter layer 24, in order from the lower layer side closer to the semiconductor substrate 21. On the inter-lens light-shielding film 23, partition walls 74 separating each inner lens 72 are formed in a grid pattern in a plan view.

[0110] The first planarization film 71 covers the insulating film 22 and the interlens light-shielding film 23 formed on the back surface S1, and its upper surface is a flat surface without irregularities. As the material for the first planarization film 71, for example, silicon oxide (SiO2) or silicon nitride (SiN) can be used.

[0111] Multiple inner lenses 72 are arranged for each pixel to correspond to the upper on-chip lens 25. Since four on-chip lenses 25 arranged in a 2x2 configuration are provided for the high-sensitivity pixel 2H, four inner lenses 72 arranged in a 2x2 configuration are formed on the first planarization film 71 for each pixel. The inner lenses 72 further concentrate the incident light focused by the on-chip lens 25 and direct it into the photodiode PD. Together with the on-chip lens 25, the inner lenses 72 constitute a light-gathering section that concentrates the incident light.

[0112] The second planarization film 73 covers the light incident surface of the inner lens 72, making the surface on the color filter layer 24 side a flat surface without irregularities. For example, the same material as the first planarization film 71 can be used for the second planarization film 73.

[0113] The first planarization film 71, the inner lens 72, and the second planarization film 73 are divided into multiple regions by partition walls 74, corresponding to the number of on-chip lenses 25. The partition walls 74 are arranged in a grid pattern in plan view, separating each inner lens 72. This prevents light incident on one inner lens 72 region from leaking into the region of an adjacent inner lens 72, thereby suppressing color mixing. The end of the partition wall 74 on the semiconductor substrate 21 side is in contact with the inter-lens light-shielding film 23. For example, metals such as aluminum (Al), tungsten (W), and copper (Cu) can be used as the material for the partition wall 74. If the same metal as the inter-lens light-shielding film 23 is used as the material for the partition wall 74, the partition wall 74 and the inter-lens light-shielding film 23 may be formed integrally.

[0114] As described above, the high-sensitivity pixel 2H in the sixth embodiment can be configured by further adding an inner lens 72 to the pixel structure of the high-sensitivity pixel 2H of the first embodiment shown in Figure 3.

[0115] In the sixth embodiment, although not shown in the figures, the low-sensitivity pixels 2La to 2Lc also have a configuration in which a first planarization film 71, an inner lens 72, a second planarization film 73, and a partition wall portion 74 are added to the pixel structure of the low-sensitivity pixels 2La to 2Lc of the first embodiment. In the low-sensitivity pixel 2L, the inner lens 72 is positioned between the on-chip lens 25 and the light-reducing film 23X.

[0116] Furthermore, if there are concerns about asymmetry in the oblique incidence characteristics due to color mixing components, a second interlens light-shielding film 81 may be further formed on the second planarization film 73 on the on-chip lens 25 side of the inner lens 72, as shown in Figure 25. The second interlens light-shielding film 81 is formed in a grid pattern in a plan view at the same position as the lower interlens light-shielding film 23. By further adding the second interlens light-shielding film 81, color mixing components can be further suppressed.

[0117] In the sixth embodiment configured as described above, it is possible to configure attenuating pixels with a desired sensitivity difference from the high-sensitivity pixels 2H using the low-sensitivity pixels 2La to 2Lc, and since symmetry in the vertical, horizontal, and diagonal directions can be maintained, it is possible to attenuate light while maintaining angular responsiveness to incident light as much as possible. Furthermore, since the area of ​​the photoelectric conversion region is not changed by the high-sensitivity pixels 2H and the low-sensitivity pixels 2L, and the design is not dependent on the design of the light-gathering focus position, it is possible to have a degree of design freedom. By further providing the inner lens 72, the light-gathering efficiency can be further increased.

[0118] Similarly to the pixel structures of the second to fifth embodiments described above, a first planarization film 71, an inner lens 72, a second planarization film 73, and a partition wall portion 74 can be added between the insulating film 22 and the interlens light-shielding film 23 and the color filter layer 24, and an additional inner lens 72 can be added. This further improves the light-gathering efficiency.

[0119] <9. Summary of Pixel Configuration Examples> The light detection device 1 includes a pixel array section 3 in which a plurality of pixels 2, including a high-sensitivity pixel 2H having a first sensitivity and a plurality of types of low-sensitivity pixels 2L having a sensitivity lower than the first sensitivity, are arranged in a matrix in a two-dimensional manner. The high-sensitivity pixels 2H and low-sensitivity pixels 2L each have a photoelectric conversion unit (photodiode PD) formed on a semiconductor substrate 21 and a plurality of on-chip lenses 25 formed on the light incident surface side of the semiconductor substrate 21. The low-sensitivity pixels 2L further have a light-reducing film (light-reducing films 23X to 23Z) positioned between the plurality of on-chip lenses 25 and the semiconductor substrate 21, which blocks a portion of the light incident on the photoelectric conversion unit. One on-chip lens 25 is divided into four equal parts symmetrically in the vertical, horizontal, and diagonal directions, and each of these regions is defined as a light incident unit region. When the number of light incident unit regions for the high-sensitivity pixels 2H and the plurality of low-sensitivity pixels 2L is counted, the sum of the light incident unit regions for the high-sensitivity pixels 2H and the plurality of low-sensitivity pixels 2L is a multiple of a predetermined value ("4").

[0120] By providing high-sensitivity pixels 2H and low-sensitivity pixels 2L in the pixel array 3 as described above, and acquiring pixel signals with different sensitivities, it is possible to configure attenuating pixels with a desired sensitivity difference relative to the high-sensitivity pixels 2H using multiple types of low-sensitivity pixels 2L. Furthermore, by arranging the attenuation films 23X to 23Z of the low-sensitivity pixels 2L in a way that maintains symmetry in the vertical, horizontal, and diagonal directions within the pixel or the pixel array 3, it is possible to attenuate light while maintaining as much as possible the angular response of the oblique incidence characteristics of the normalized sensitivity. Therefore, the light detection device 1 can more appropriately attenuate incident light and achieve a high dynamic range.

[0121] The combination of high-sensitivity pixels 2H and low-sensitivity pixels 2L allows for greater design flexibility because the area of ​​the photoelectric conversion region is not affected by the design of the light-gathering focus position.

[0122] In the above-described embodiment, an example was explained in which four on-chip lenses 25 arranged in a 2x2 grid and nine on-chip lenses 25 arranged in a 3x3 grid were placed in one pixel. However, as long as device process fabrication is feasible, a configuration with NxN (where N is 2 or more) on-chip lenses 25 can be arranged. The resolution of sensitivity adjustment can be increased according to the NxN number of divisions in which the on-chip lenses 25 are arranged.

[0123] <10. Examples of Electronic Device Configurations> The light detection device 1 described above can be applied to various electronic devices such as imaging systems like digital still cameras and digital video cameras, mobile phones equipped with imaging functions, or other devices equipped with imaging functions.

[0124] Figure 26 is a block diagram showing an example of the configuration of an electronic device.

[0125] As shown in Figure 26, the electronic device 101 comprises an optical system 102, a light detection device 103, a DSP (Digital Signal Processor) 104, a display device 105, an operating system 106, a memory 107, a recording device 108, and a power supply system 109. The DSP 104, display device 105, operating system 106, memory 107, recording device 108, and power supply system 109 are interconnected via a bus 110. The electronic device 101 is, for example, an imaging device capable of capturing still images and moving images.

[0126] The optical system 102 is composed of one or more lenses and guides the image light (incident light) from the subject to the light detection device 103, where it forms an image on the light-receiving surface (sensor part) of the light detection device 103.

[0127] In the photodetector 103, electrons as signal charges are accumulated for a certain period of time according to the image formed on the light-receiving surface via the optical system 102. Then, a signal corresponding to the electrons accumulated in the photodetector 103 is supplied to the DSP 104. As the photodetector 103, the photodetector 1 described above, that is, a photodetector that expands the dynamic range and achieves high dynamic range by providing high-sensitivity pixels 2H and low-sensitivity pixels 2L in the pixel array section 3 and acquiring pixel signals with a sensitivity difference, can be used.

[0128] The DSP 104 performs various signal processing on the signal from the light detection device 103 to generate an image, and temporarily stores the image data in the memory 107. The image data stored in the memory 107 is recorded in the recording device 108 or supplied to the display device 105 to display the image. The operation system 106 receives various operations from the user and supplies operation signals to each block of the electronic equipment 101, and the power supply system 109 supplies the power necessary to drive each block of the electronic equipment 101.

[0129] In the electronic device 101 configured in this way, by applying the above-described light detection device 1 as the light detection device 103, the dynamic range can be expanded and high dynamic range can be achieved. Therefore, high-quality captured images can be generated.

[0130] <11. Example of Image Sensor Use> Figure 27 shows an example of use when the above-mentioned light detection device 1 is an image sensor.

[0131] If the above-mentioned light detection device 1 is an image sensor, it can be used in various cases to sense light such as visible light, infrared light, ultraviolet light, and X-rays, for example, as follows.

[0132] - Devices that capture images for viewing purposes, such as digital cameras and portable devices with camera functions. - Devices used for traffic purposes, such as in-vehicle sensors that capture images of the front, rear, surroundings, and interior of a vehicle for safe driving such as automatic stopping and recognition of the driver's condition, surveillance cameras that monitor moving vehicles and roads, and distance measuring sensors that measure distances between vehicles. - Devices used in home appliances such as TVs, refrigerators, and air conditioners that capture user gestures and allow device operation according to those gestures. - Devices used for medical and healthcare purposes, such as endoscopes and devices that perform angiography using infrared light reception. - Devices used for security purposes, such as surveillance cameras for crime prevention and cameras for person recognition. - Devices used for beauty purposes, such as skin measuring devices that capture images of skin and microscopes that capture images of the scalp. - Devices used for sports purposes, such as action cameras and wearable cameras for sports use. - Devices used for agriculture, such as cameras that monitor the condition of fields and crops.

[0133] <12. Examples of Application to Mobile Devices> The technology relating to this disclosure (this technology) can be applied to various products. For example, the technology relating to this disclosure 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, and robots.

[0134] Figure 28 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.

[0135] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 28, 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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 28, 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.

[0145] Figure 29 shows an example of the installation position of the imaging unit 12031.

[0146] In Figure 29, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0147] 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.

[0148] Figure 29 shows an example of the imaging ranges 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.

[0149] 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.

[0150] For example, the microcomputer 12051, based on distance information obtained from imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to 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 before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0151] 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.

[0152] 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.

[0153] The above describes an example of a vehicle control system to which the technology described herein may be applied. The technology described herein can be applied to the imaging unit 12031 of the configuration described above. Specifically, the above-described light detection device 1 can be applied as the imaging unit 12031. By applying the technology described herein to the imaging unit 12031, it is possible to obtain clearer captured images and acquire distance information while miniaturizing the unit. Furthermore, by using the obtained captured images and distance information, it becomes possible to reduce driver fatigue and improve the safety of the driver and the vehicle.

[0154] In the example described above, a solid-state imaging device was described in which the first conductivity type was P-type and the second conductivity type was N-type, and electrons were used as the signal charge. However, this disclosure can also be applied to a solid-state imaging device in which holes are used as the signal charge. That is, the first conductivity type can be N-type and the second conductivity type can be P-type, and each of the aforementioned semiconductor regions can be composed of semiconductor regions of the opposite conductivity type.

[0155] Furthermore, this disclosure is not limited to applications to solid-state imaging devices that detect the distribution of incident light intensity of visible light and capture it as an image, but is also applicable to solid-state imaging devices that capture the distribution of incident light intensity of infrared rays, X-rays, or particles as an image, and in a broader sense, to solid-state imaging devices (physical quantity distribution detection devices) in general, such as fingerprint detection sensors that detect the distribution of other physical quantities such as pressure and capacitance and capture it as an image.

[0156] Furthermore, the technology disclosed herein is applicable not only to photodetectors but also to semiconductor devices in general that have other semiconductor integrated circuits.

[0157] In this specification, a system refers to a collection of multiple components (devices, modules (parts), etc.), regardless of whether all components are located in the same enclosure. Therefore, multiple devices housed in separate enclosures and connected via a network, and a single device containing multiple modules within a single enclosure, are both considered systems.

[0158] Furthermore, the embodiments of the technology disclosed herein are not limited to those described above, and various modifications are possible without departing from the gist of the technology disclosed herein.

[0159] Furthermore, the effects described herein are merely illustrative and not limiting, and other effects may also occur.

[0160] Furthermore, the technology of this disclosure may employ the following configuration: (1) A light detection device comprising a pixel array portion in which a plurality of pixels, including a high-sensitivity pixel having a first sensitivity and a plurality of types of low-sensitivity pixels having a sensitivity lower than the first sensitivity, are arranged in a matrix in a two-dimensional manner, wherein the high-sensitivity pixel and the low-sensitivity pixel each have a photoelectric conversion portion formed on a semiconductor substrate and a plurality of on-chip lenses formed on the light incident surface side of the semiconductor substrate, and the low-sensitivity pixel further has a light-reducing film disposed between the plurality of on-chip lenses and the semiconductor substrate, which blocks a portion of the light incident on the photoelectric conversion portion, and a region corresponding to one of the on-chip lenses is divided into four equal parts so as to be symmetrical in the vertical, horizontal, and diagonal directions, and one region obtained by dividing the region corresponding to one of the on-chip lenses into four equal parts is defined as a light incident unit region, and when the number of light incident unit regions of the high-sensitivity pixel and the plurality of types of low-sensitivity pixels is counted by the number of light incident unit regions, the sum of the light incident unit regions of the high-sensitivity pixel and the plurality of types of low-sensitivity pixels is a multiple of a predetermined value. (2) The photodetector according to (1), wherein the plurality of on-chip lenses are four on-chip lenses arranged in a 2x2 configuration. (3) The photodetector according to (1), wherein the plurality of on-chip lenses are nine on-chip lenses arranged in a 3x3 configuration. (4) The photodetector according to any one of (1) to (3), wherein the predetermined value is "4". (5) The photodetector according to any one of (1) to (4), wherein the predetermined value is the number of light incidence unit regions corresponding to the light incidence region of the lowest sensitivity low-sensitivity pixel. (6) The photodetector according to any one of (1) to (5), wherein the high-sensitivity pixel and the low-sensitivity pixel further have an interlens light-shielding film provided in a grid pattern at the boundary of the on-chip lens in a plan view. (7) The photodetector according to any one of (1) to (6), wherein the high-sensitivity pixel and the low-sensitivity pixel further have the same number of inner lenses between the on-chip lens and the light-reducing film as the on-chip lens. (8) The light detection device according to (7), wherein the high-sensitivity pixels and the low-sensitivity pixels are arranged in a grid pattern in a plan view, and further comprises a partition wall separating the inner lens and a second interlens light-shielding film provided in a grid pattern in a plan view on the side of the inner lens to the on-chip lens.(9) The light detection device according to any one of (1) to (8), wherein a portion of the low-sensitivity pixels includes a pixel that outputs a phase difference signal. (10) The light detection device according to any one of (1) to (9), wherein the boundary line between the light-reducing region and the light-incident region due to the light-reducing film is at a 45-degree angle to the horizontal or vertical direction of the pixel array. (11) The light detection device according to (10), wherein the upper surface of the end face of the light-reducing film that forms the boundary line has an uneven shape. (12) The light detection device according to any one of (1) to (11), wherein the arrangement of the light-reducing film of the low-sensitivity pixels is symmetrical in the diagonal directions of up, down, left, right, and within the pixel. (13) The light detection device according to any one of (1) to (12), wherein there are three types of sensitivity for the low-sensitivity pixels. (14) The light detection device according to any one of (1) to (12), wherein there are eight types of sensitivity for the low-sensitivity pixels. (15) An electronic device comprising a pixel array portion in which a plurality of pixels, including a high-sensitivity pixel having a first sensitivity and a plurality of types of low-sensitivity pixels having a sensitivity lower than the first sensitivity, are arranged in a matrix in a two-dimensional manner, wherein the high-sensitivity pixel and the low-sensitivity pixel each have a photoelectric conversion portion formed on a semiconductor substrate and a plurality of on-chip lenses formed on the light incident surface side of the semiconductor substrate, and the low-sensitivity pixel further has a light-reducing film disposed between the plurality of on-chip lenses and the semiconductor substrate to block a portion of the light incident on the photoelectric conversion portion, and the region corresponding to one of the on-chip lenses is divided into four equal parts so as to be symmetrical in the vertical, horizontal, and diagonal directions, and one region obtained by dividing the region into four equal parts is defined as a light incident unit region, and when the number of light incident unit regions is counted for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels, the sum of the light incident unit regions is a multiple of a predetermined value for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels.

[0161] 1. Light detection device, 2. Pixels, 2H, 2H' high-sensitivity pixels, 2L, 2La to 2Lc, 2La' to 2Lh' low-sensitivity pixels, 3. Pixel array section, PD photodiode, 21. Semiconductor substrate, 22. Insulating film, 23. Interlens light-shielding film, 23X, 23Y, 23Z light-reducing film, 24. Color filter layer, 25. On-chip lens, 31. Wiring layer, 32. Metal wiring, 33. Interlayer insulating film, 41. P-type semiconductor region, 42. N-type semiconductor region, 71. First planarization film, 72. Inner lens, 73. Second planarization film, 74. Partition wall section, 81. Second interlens light-shielding film, 101. Electronic device, 103. Light detection device, OCLB1 lens region (light incident unit region), OCLB2 lens region (light incident unit region)

Claims

1. A light detection device comprising a pixel array portion in which a plurality of pixels, including a high-sensitivity pixel having a first sensitivity and a plurality of types of low-sensitivity pixels having a sensitivity lower than the first sensitivity, are arranged in a matrix in a two-dimensional manner, wherein the high-sensitivity pixel and the low-sensitivity pixel each have a photoelectric conversion portion formed on a semiconductor substrate and a plurality of on-chip lenses formed on the light incident surface side of the semiconductor substrate, and the low-sensitivity pixel further has a light-reducing film disposed between the plurality of on-chip lenses and the semiconductor substrate to block a portion of the light incident on the photoelectric conversion portion, wherein the region corresponding to one of the on-chip lenses is divided into four equal parts so as to be symmetrical in the vertical, horizontal, and diagonal directions, and one region obtained by dividing the region into four equal parts is defined as a light incident unit region, and when the number of light incident unit regions is counted for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels, the sum of the light incident unit regions is a multiple of a predetermined value for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels.

2. The photodetector according to claim 1, wherein the plurality of on-chip lenses are four on-chip lenses arranged in a 2x2 configuration.

3. The photodetector according to claim 1, wherein the plurality of on-chip lenses are nine on-chip lenses arranged in a 3x3 configuration.

4. The light detection device according to claim 1, wherein the predetermined value is "4".

5. The photodetector according to claim 1, wherein the predetermined value is the number of light incident unit regions corresponding to the light incident region of the lowest sensitivity pixel.

6. The light detection device according to claim 1, wherein the high-sensitivity pixels and the low-sensitivity pixels further have interlens light-shielding films provided in a grid pattern at the boundary of the on-chip lens in a plan view.

7. The light detection device according to claim 1, wherein the high-sensitivity pixels and the low-sensitivity pixels further have the same number of inner lenses between the on-chip lens and the light-reducing film as the on-chip lens.

8. The light detection device according to claim 7, wherein the high-sensitivity pixels and the low-sensitivity pixels are arranged in a grid pattern in a plan view, and further comprises a partition wall separating the inner lens and a second inter-lens light-shielding film provided in a grid pattern in a plan view on the side of the inner lens to the on-chip lens.

9. The photodetector according to claim 1, wherein a portion of the low-sensitivity pixels includes pixels that output a phase difference signal.

10. The light detection device according to claim 1, wherein the boundary line between the light-reducing region and the light-incident region due to the light-reducing film is in an oblique direction of 45 degrees with respect to the horizontal or vertical direction of the pixel array portion.

11. The light detection device according to claim 10, wherein the upper surface of the end face of the light-reducing film that forms the boundary line has an uneven shape.

12. The light detection device according to claim 1, wherein the arrangement of the light-reducing film of the low-sensitivity pixel is symmetrical in the diagonal directions (up, down, left, right, and right) within the pixel.

13. The light detection device according to claim 1, wherein there are three types of sensitivity for the low-sensitivity pixels.

14. The light detection device according to claim 1, wherein there are eight types of sensitivity for the low-sensitivity pixels.

15. An electronic device comprising a pixel array portion in which a plurality of pixels, including a high-sensitivity pixel having a first sensitivity and a plurality of types of low-sensitivity pixels having a sensitivity lower than the first sensitivity, are arranged in a matrix in a two-dimensional manner, wherein the high-sensitivity pixel and the low-sensitivity pixel each have a photoelectric conversion portion formed on a semiconductor substrate and a plurality of on-chip lenses formed on the light incident surface side of the semiconductor substrate, and the low-sensitivity pixel further has a light-reducing film disposed between the plurality of on-chip lenses and the semiconductor substrate to block a portion of the light incident on the photoelectric conversion portion, and the region corresponding to one of the on-chip lenses is divided into four equal parts so as to be symmetrical in the vertical, horizontal, and diagonal directions, and one region obtained by dividing the region into four equal parts is defined as a light incident unit region, and when the number of light incident unit regions is counted for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels, the sum of the light incident unit regions is a multiple of a predetermined value for the high-sensitivity pixel and the plurality of types of low-sensitivity pixels.

Images