Light receiving device and distance measuring system

Abstract

A light-receiving device and a distance-measuring system capable of reliably receiving light using reference pixels. The light-receiving device includes a plurality of pixels, each of which comprises a light-receiving element having a light-receiving surface and a light source disposed on the opposite side of the light-receiving element from the light-receiving surface. The plurality of pixels includes a first pixel having a light-shielding component disposed between the light-receiving element and the light source, and a second pixel having a light-guiding portion for transmitting photons between the light-receiving element and the light source. This technology can be applied, for example, to distance-measuring systems that detect the depth distance of a subject.

Description

Technical Field

[0001] The present technology relates to a light receiving device and a distance measuring system, and in particular, to a light receiving device and a distance measuring system capable of reliably receiving light using reference pixels. Background Art

[0002] In recent years, distance sensors that measure distance using the ToF (Time-of-Flight) method have attracted attention. For example, some use SPADs (Single Photon Avalanche Diodes) in their pixels. In a SPAD, when a voltage greater than the breakdown voltage is applied and a single photon enters the high-electric-field PN junction region, avalanche amplification occurs. By detecting the timing of the instantaneous current flow at this point, distance can be measured with high precision.

[0003] For example, Patent Document 1 discloses a technique in which a distance measuring sensor using a SPAD is provided with measurement pixels and reference pixels, and the reference pixels are used to measure the intensity of background light and change the bias voltage of the SPAD.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-81254 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] However, the technology of Patent Document 1 is unreliable because background light is used as the light detected by the reference pixels.

[0009] The present technology has been developed in view of such circumstances and can reliably receive light using reference pixels.

[0010] Technical solutions to technical problems

[0011] A light-receiving device according to a first aspect of the present technology includes a plurality of pixels, each of which includes: a light-receiving element having a light-receiving surface; and a light-emitting source arranged on the side opposite to the light-receiving surface relative to the light-receiving element, wherein the plurality of pixels include: a first pixel having a light-shielding component arranged between the light-receiving element and the light-emitting source; and a second pixel having a light-guiding portion for transmitting photons between the light-receiving element and the light-emitting source.

[0012] The ranging system of the second aspect of the present technology includes: an illumination device that irradiates irradiation light; and a light receiving device that receives reflected light of the irradiation light, the light receiving device including a plurality of pixels, the plurality of pixels having: a light receiving element having a light receiving surface; and a light source that is arranged on the side opposite to the light receiving surface relative to the light receiving element, the plurality of pixels including: a first pixel having a light shielding component arranged between the light receiving element and the light source; and a second pixel having a light guiding portion that transmits photons between the light receiving element and the light source.

[0013] In the first to third aspects of the present technology, a plurality of pixels are provided, each including: a light-receiving element having a light-receiving surface; and a light-emitting source disposed on a side opposite to the light-receiving surface of the light-receiving element. The plurality of pixels include: a first pixel having a light-shielding member disposed between the light-receiving element and the light-emitting source; and a second pixel having a light-guiding portion for transmitting photons between the light-receiving element and the light-emitting source.

[0014] The light receiving device and the distance measuring system may be independent devices or components assembled into other devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a block diagram showing a configuration example of an embodiment of a distance measurement system to which the present technology is applied.

[0016] Figure 2 It shows Figure 1 A block diagram of an example of the configuration of a light receiving device.

[0017] Figure 3 A diagram showing an example of a circuit configuration of a pixel.

[0018] Figure 4 It is an explanation Figure 3 A diagram of the action of pixels.

[0019] Figure 5 It is a top view of the light source and pixel array.

[0020] Figure 6 is a cross-sectional view of a pixel.

[0021] Figure 7 1 is a diagram showing a configuration example of a light source and a pixel array in another distance measurement system as a comparative example.

[0022] Figure 8 It is a cross-sectional view showing another example of pixel arrangement.

[0023] Figure 9 This is a diagram illustrating an example of use of a distance measurement system.

[0024] Figure 10This is a block diagram showing an example of a schematic configuration of a vehicle control system.

[0025] Figure 11 It is an explanatory diagram showing an example of the installation positions of the vehicle exterior information detection unit and the imaging unit. DETAILED DESCRIPTION

[0026] Hereinafter, a method for implementing the present technology (hereinafter referred to as an embodiment) will be described in the following order.

[0027] 1. Example of Distance Measurement System Configuration

[0028] 2. Example of the structure of the light receiving device

[0029] 3. Example of pixel circuit configuration

[0030] 4. Top view of light source and pixel array

[0031] 5. Pixel cross-section

[0032] 6. Comparative Examples

[0033] 7. Other pixel arrangement examples

[0034] 8. Example of using the distance measurement system

[0035] 9. Application examples to mobile objects

[0036] <1. Example of Distance Measurement System Configuration>

[0037] Figure 1 This is a block diagram showing a configuration example of an embodiment of a distance measurement system to which the present technology is applied.

[0038] The distance measurement system 11 is a system for capturing distance images using, for example, the ToF method. Here, the distance image is detected pixel by pixel from the distance measurement system 11 to the subject in the depth direction, and the signal of each pixel is composed of a distance pixel signal based on the detected distance.

[0039] The distance measurement system 11 includes an illumination device 21 and a photographing device 22 .

[0040] The lighting device 21 includes a lighting control unit 31 and a light source 32 .

[0041] The lighting control unit 31 controls the pattern of light emitted by the light source 32 under the control of the control unit 42 of the imaging device 22. Specifically, the lighting control unit 31 controls the pattern of light emitted by the light source 32 based on an illumination code included in the illumination signal provided by the control unit 42. For example, the illumination code consists of binary values ​​of 1 (high) and 0 (low). When the illumination code value is 1, the lighting control unit 31 turns on the light source 32, and when the illumination code value is 0, the lighting control unit 31 turns off the light source 32.

[0042] The light source 32 emits light within a predetermined wavelength range under the control of the illumination control unit 31. The light source 32 is composed of, for example, an infrared laser diode. The type of the light source 32 and the wavelength range of the irradiated light can be arbitrarily set according to the application of the distance measurement system 11.

[0043] The imaging device 22 receives reflected light emitted from the lighting device 21 (illumination light) by the subjects 12 and 13 , etc. The imaging device 22 includes an imaging unit 41 , a control unit 42 , a display unit 43 , and a storage unit 44 .

[0044] The imaging unit 41 includes a lens 51 and a light receiving device 52 .

[0045] The lens 51 forms an image of incident light on the light receiving surface of the light receiving device 52. The structure of the lens 51 is arbitrary, and for example, the lens 51 may be composed of a plurality of lens groups.

[0046] The light receiving device 52 is composed of a sensor that uses a SPAD (single photon avalanche diode) for each pixel, for example. Under the control of the control unit 42, the light receiving device 52 receives reflected light from the subject 12, the subject 13, etc., converts the obtained pixel signal into distance information, and outputs the distance information to the control unit 42. The light receiving device 52 provides the control unit 42 with a distance image that stores a digital count value as the pixel value (distance pixel signal) of each pixel in a pixel array in which pixels are two-dimensionally arranged in a matrix in the row and column directions, wherein the digital count value is obtained by counting the time from the time the illumination device 21 emits the irradiation light until the light receiving device 52 receives the light. A light emission timing signal indicating the timing of the light source 32 emitting light is also provided to the light receiving device 52 from the control unit 42.

[0047] In addition, the distance measuring system 11 repeats the light emission of the light source 32 and the reception of its reflected light many times (for example, thousands to tens of thousands), so that the imaging unit 41 generates a distance image without the influence of interference light and multipath, and provides it to the control unit 42.

[0048] The control unit 42 is composed of a control circuit, a processor, and the like, such as an FPGA (Field Programmable Gate Array) and a DSP (Digital Signal Processor). The control unit 42 controls the lighting control unit 31 and the light receiving device 52. Specifically, the control unit 42 provides an illumination signal to the lighting control unit 31, and provides a light-emitting timing signal to the light receiving device 52. The light source 32 emits illumination light according to the illumination signal. The light-emitting timing signal may be an illumination signal provided to the lighting control unit 31. In addition, the control unit 42 provides the distance image obtained from the shooting unit 41 to the display unit 43, and causes the display unit 43 to display it. In addition, the control unit 42 stores the distance image obtained from the shooting unit 41 in the storage unit 44. In addition, the control unit 42 outputs the distance image obtained from the shooting unit 41 to the outside.

[0049] The display unit 43 includes a panel-type display device such as a liquid crystal display device or an organic EL (Electro Luminescence) display device.

[0050] The storage unit 44 can be constituted by any storage device or storage medium, and stores distance images and the like.

[0051] <2. Example of the structure of the light receiving device>

[0052] Figure 2 2 is a block diagram showing a configuration example of the light receiving device 52 .

[0053] The light receiving device 52 includes a pixel driving section 71 , a pixel array 72 , a MUX (multiplexer) 73 , a time measuring section 74 , a signal processing section 75 , and an input / output section 76 .

[0054] The pixel array 72 has the following structure: pixels 81 that output detection signals indicating detection results as pixel signals are arranged in a two-dimensional matrix in the row and column directions. Here, the row direction refers to the arrangement direction of the pixels 81 in the horizontal direction, and the column direction refers to the arrangement direction of the pixels 81 in the vertical direction. Figure 2 In the figure, due to paper limitations, the pixel array 72 is shown as having 10 rows and 12 columns of pixels. However, the number of rows and columns of the pixel array 72 is not limited thereto and is arbitrary.

[0055] Relative to the matrix pixel arrangement of the pixel array 72, pixel drive lines 82 are wired in the horizontal direction for each pixel row. The pixel drive lines 82 transmit drive signals for driving the pixels 81. The pixel drive unit 71 drives each pixel 81 by providing a predetermined drive signal to each pixel 81 via the pixel drive line 82. Specifically, the pixel drive unit 71 performs the following control: at a predetermined timing according to a light-emitting timing signal provided from the outside via the input-output unit 76, at least a portion of the plurality of pixels 81 arranged in a two-dimensional matrix becomes active pixels, and the remaining pixels 81 become inactive pixels. Active pixels are pixels that detect the incidence of photons, and inactive pixels are pixels that do not detect the incidence of photons. Of course, all pixels 81 of the pixel array 72 can be active pixels. The detailed structure of the pixels 81 will be described later.

[0056] In addition, Figure 2 In FIG. 8 , the pixel drive line 82 is shown as a single wiring, but may be composed of a plurality of wirings. One end of the pixel drive line 82 is connected to an output end corresponding to each pixel row of the pixel drive unit 71.

[0057] The MUX 73 selects an output from an active pixel according to the switching between active pixels and inactive pixels in the pixel array 72. The MUX 73 then outputs the pixel signal input from the selected active pixel to the time measurement unit 74.

[0058] Based on the pixel signal of the active pixel supplied from the MUX 73 and the emission timing signal indicating the emission timing of the light source 32, the time measurement unit 74 generates a count value corresponding to the time from when the light source 32 emits light until the active pixel receives light. The time measurement unit 74 is also called a TDC (time-to-digital converter). The emission timing signal is supplied from the outside (control unit 42 of the imaging device 22) via the input / output unit 76.

[0059] Based on the repetition of the light emission of the light source 32 and the reception of its reflected light a predetermined number of times (for example, thousands to tens of thousands of times), the signal processing unit 75 creates a histogram of the time (count value) until the reflected light is received for each pixel. Then, the signal processing unit 75 determines the time until the light emitted from the light source 32 is reflected by the subject 12 or the subject 13 and returns by detecting the peak of the histogram. The signal processing unit 75 generates a distance image in which a digital count value is stored in each pixel, and provides it to the input-output unit 76, wherein the digital count value is obtained by counting the time until the light receiving device 52 receives light. Alternatively, the signal processing unit 75 may perform a calculation for determining the distance to the object based on the determined time and the speed of light, generate a distance image in which the calculation result is stored in each pixel, and provide it to the input-output unit 76.

[0060] The input / output unit 76 outputs the distance image signal (distance image signal) supplied from the signal processing unit 75 to the outside (control unit 42 ). Furthermore, the input / output unit 76 receives the light emission timing signal supplied from the control unit 42 and supplies it to the pixel driving unit 71 and the time measuring unit 74 .

[0061] <3. Example of Pixel Circuit Configuration>

[0062] Figure 3 A circuit configuration example is shown in which a plurality of pixels 81 are arranged in a matrix in the pixel array 72 .

[0063] Figure 3 The pixel 81 includes a SPAD 101, a transistor 102, a switch 103, and an inverter 104. In addition, the pixel 81 further includes a latch circuit 105 and an inverter 106. The transistor 102 is a P-type MOS transistor.

[0064] The cathode of the SPAD 101 is connected to the drain of the transistor 102, the input terminal of the inverter 104, and one end of the switch 103. The anode of the SPAD 101 is connected to the power supply voltage VA (hereinafter also referred to as the anode voltage VA).

[0065] The SPAD 101 is a photodiode (single photon avalanche photodiode) that amplifies electrons generated by incident light and outputs a cathode voltage VS signal. The power supply voltage VA supplied to the anode of the SPAD 101 is a negative bias voltage (negative potential) of approximately -20V, for example.

[0066] Transistor 102 is a constant current source operating in the saturation region and performs passive quenching by acting as a quenching resistor. The source of transistor 102 is connected to the power supply voltage VE, and the drain is connected to the cathode of SPAD 101, the input terminal of inverter 104, and one end of switch 103. Thus, the power supply voltage VE is also supplied to the cathode of SPAD 101. A pull-up resistor can be used instead of transistor 102 connected in series with SPAD 101.

[0067] In order to detect light (photons) with sufficient efficiency, a voltage greater than the breakdown voltage VBD of the SPAD 101 (hereinafter referred to as "excess bias") is applied to the SPAD 101. For example, if the breakdown voltage VBD of the SPAD 101 is 20V and a voltage 3V higher than the breakdown voltage VBD is applied, the power supply voltage VE supplied to the source of the transistor 102 is 3V.

[0068] In addition, the breakdown voltage VBD of the SPAD 101 varies greatly depending on temperature, etc. Therefore, the applied voltage to the SPAD 101 is controlled (adjusted) according to the variation in the breakdown voltage VBD. For example, when the power supply voltage VE is a fixed voltage, the anode voltage VA is controlled (adjusted).

[0069] One end of switch 103 is connected to the cathode of SPAD 101, the input terminal of inverter 104, and the drain of transistor 102, and the other end is connected to ground line 107, which is connected to ground (GND). Switch 103 can be composed of, for example, an N-type MOS transistor, and switches the gate control signal VG, which is the output of latch circuit 105, on and off based on the gate inversion signal VG_I ​​inverted by inverter 106.

[0070] The latch circuit 105 supplies a gate control signal VG for controlling the pixel 81 as an active pixel or an inactive pixel to the inverter 106 based on the trigger signal SET and the address data DEC supplied from the pixel driver 71. The inverter 106 generates a gate inversion signal VG_I ​​obtained by inverting the gate control signal VG and supplies it to the switch 103.

[0071] The trigger signal SET is a timing signal indicating the timing for switching the gate control signal VG, and the address data DEC is data indicating the address of a pixel set as an active pixel among the plurality of pixels 81 arranged in a matrix within the pixel array 72. The trigger signal SET and the address data DEC are supplied from the pixel driving section 71 via the pixel driving line 82.

[0072] The latch circuit 105 reads the address data DEC at a predetermined timing indicated by the trigger signal SET. In addition, when the pixel address indicated by the address data DEC includes the pixel address of the own pixel (the pixel 81), the latch circuit 105 outputs the strobe control signal VG of Hi(1) for setting the own pixel 81 as an active pixel. On the other hand, when the pixel address indicated by the address data DEC does not include the pixel address of the own pixel (the pixel 81), the latch circuit 105 outputs the strobe control signal VG of Lo(0) for setting the own pixel 81 as an inactive pixel. Thus, when the pixel 81 becomes an active pixel, the strobe inversion signal VG_I ​​of Lo(0) inverted by the inverter 106 is provided to the switch 103. On the other hand, when the pixel 81 becomes an inactive pixel, the strobe inversion signal VG_I ​​of Hi(1) is provided to the switch 103. Therefore, when the pixel 81 is set as an active pixel, the switch 103 is turned off (disconnected), and when it is set as an inactive pixel, the switch 103 is turned on (connected).

[0073] The inverter 104 outputs a Hi detection signal PFout when the cathode voltage VS as an input signal is Lo, and outputs a Lo detection signal PFout when the cathode voltage VS is Hi. The inverter 104 is an output unit that outputs the incidence of photons on the SPAD 101 as a detection signal PFout.

[0074] Next, refer to Figure 4 The operation when the pixel 81 is set as an active pixel will be described.

[0075] Figure 4 Graphs showing changes in the cathode voltage VS of the SPAD 101 and the detection signal PFout according to incidence of photons.

[0076] First, when the pixel 81 is an active pixel, the switch 103 is set to OFF as described above.

[0077] Since the power supply voltage VE (for example, 3V) is supplied to the cathode of the SPAD 101 and the power supply voltage VA (for example, -20V) is supplied to the anode, a reverse voltage greater than the breakdown voltage VBD (=20V) is applied to the SPAD 101, and the SPAD 101 is set to the Geiger mode. In this state, for example, Figure 4 At time t0 , the cathode voltage VS of the SPAD 101 is the same as the power supply voltage VE.

[0078] When a photon is incident on the SPAD 101 set to Geiger mode, avalanche multiplication occurs and current flows into the SPAD 101 .

[0079] If in Figure 4 Avalanche multiplication occurs at time t1 and current flows into the SPAD 101. Then, current flows into the SPAD 101 after time t1, and thus current also flows into the transistor 102, causing a voltage drop due to the resistance component of the transistor 102.

[0080] At time t2, the cathode voltage VS of each SPAD 101 falls below 0V, and the voltage between the anode and cathode of the SPAD 101 falls below the breakdown voltage VBD, thereby stopping avalanche amplification. Here, the current generated by avalanche amplification flows into the transistor 102, causing a voltage drop. As this voltage drops, the cathode voltage VS falls below the breakdown voltage VBD, thereby stopping avalanche amplification. This is called quenching.

[0081] When avalanche amplification stops, the current flowing into the resistor of the transistor 102 gradually decreases, and at time t4, the cathode voltage VS returns to the original power supply voltage VE again, becoming a state capable of detecting the next new photon (recharging operation).

[0082] When the input voltage, cathode voltage VS, is above a predetermined threshold voltage Vth, inverter 104 outputs a detection signal PFout of Low. When cathode voltage VS is below the predetermined threshold voltage Vth, inverter 104 outputs a detection signal PFout of High. Therefore, when photons strike SPAD 101, avalanche multiplication occurs, causing cathode voltage VS to decrease and fall below threshold voltage Vth. Detection signal PFout inverts from a low level to a high level. On the other hand, when avalanche multiplication in SPAD 101 converges, cathode voltage VS rises and remains above threshold voltage Vth, detection signal PFout inverts from a high level to a low level.

[0083] Furthermore, when pixel 81 is inactive, the inverted gate signal VG_I ​​of Hi(1) is supplied to switch 103, and switch 103 is turned on. When switch 103 is turned on, the cathode voltage VS of SPAD 101 becomes 0 V. As a result, the anode / cathode voltage of SPAD 101 becomes lower than the breakdown voltage VBD, and thus, even if a photon enters SPAD 101, it does not react.

[0084] <4. Top view of light source and pixel array>

[0085] Figure 5 A shows a top view of the light source 32 .

[0086] The light source 32 is composed of a plurality of light-emitting units 121 arranged in a matrix. The light-emitting units 121 are, for example, vertical cavity surface emitting lasers (VCSELs). The lighting control unit 31 can individually turn on and off the light-emitting units 121 arranged in the matrix according to the illumination code included in the illumination signal provided by the control unit 42.

[0087] Figure 5 FIG. 8B shows a top view of the pixel array 72 .

[0088] As described above, the pixel array 72 is configured by two-dimensionally arranging the pixels 81 in a matrix. However, each pixel 81 is functionally classified as one of the pixel 81M, the pixel 81R, and the pixel 81D.

[0089] The pixel 81M receives reflected light of the light emitted from the light source 32 (light emitting unit 121 ) and reflected by the subjects 12 and 13 , and is a pixel for measuring (distance measurement) the distance to the subject.

[0090] The pixel 81R is a reference pixel for confirming that an appropriate voltage is applied to the SPAD 101 and calibrating distance data.

[0091] Pixel 81D is a dummy pixel used to separate measurement pixel 81M from reference pixel 81R. Dummy pixel 81D may have the same pixel structure as measurement pixel 81M and may differ only in that it is not driven. Alternatively, it may have the same pixel structure as measurement pixel 81M and may be driven for internal voltage monitoring.

[0092] If a plurality of measurement pixels 81M are arranged in a matrix, and dummy pixels 81D are disposed between measurement pixels 81M and reference pixels 81R, the number of pixels 81M, 81R, and 81D is not particularly limited. Measurement pixels 81M may be arranged in a matrix of N1×N2 (N1 and N2 are integers greater than or equal to 1), reference pixels 81R may be arranged in a matrix of M1×M2 (M1 and M2 are integers greater than or equal to 1), and dummy pixels 81D may be arranged in a matrix of L1×L2 (L1 and L2 are integers greater than or equal to 1).

[0093] In addition, Figure 5 In the example, the plurality of reference pixels 81R are arranged side by side, but the reference pixel 81R may be independently arranged in the dummy pixel 81D, and the dummy pixel 81D may be arranged between the pixel 81R and other pixels 81R.

[0094] <5. Pixel Cross-Sectional Diagram>

[0095] Figure 6 A shows a cross-sectional view of the pixel 81M used for measurement.

[0096] The pixel 81M is constructed by bonding a first substrate 201 and a second substrate 202 together. The first substrate 201 includes a semiconductor substrate 211 made of silicon or the like and a wiring layer 212. Hereinafter, the wiring layer 212 will be referred to as the sensor-side wiring layer 212 to distinguish it from the wiring layer 312 on the second substrate 202 side, described later. The wiring layer 312 on the second substrate 202 side will be referred to as the logic-side wiring layer 312. The surface on which the sensor-side wiring layer 212 is formed relative to the semiconductor substrate 211 is the front surface. In the figure, the back surface, where the upper sensor-side wiring layer 212 is not formed, is the light-receiving surface on which reflected light is incident.

[0097] The pixel region of the semiconductor substrate 211 includes an N-well 221, a P-type diffusion layer 222, an N-type diffusion layer 223, a hole accumulation layer 224, and a high-concentration P-type diffusion layer 225. Furthermore, an avalanche multiplication region 257 is formed by a depletion layer formed in a region connecting the P-type diffusion layer 222 and the N-type diffusion layer 223.

[0098] The N-well 221 is formed by controlling the impurity concentration of the semiconductor substrate 211 to be n-type, creating an electric field that transfers electrons generated by photoelectric conversion in the pixel 81M to the avalanche multiplication region 257. In the center of the N-well 221, an N-type region 258 with a higher concentration than the N-well 221 is formed in contact with the P-type diffusion layer 222. This creates an electric potential gradient, allowing carriers (electrons) generated in the N-well 221 to easily drift from the periphery to the center. Alternatively, a P-well formed by controlling the impurity concentration of the semiconductor substrate 211 to be p-type can be used instead of the N-well 221.

[0099] The P-type diffusion layer 222 is a dense P-type diffusion layer (P+) formed across substantially the entire surface of the pixel region in a planar direction. The N-type diffusion layer 223, like the P-type diffusion layer 222, is a dense N-type diffusion layer (N+) formed across substantially the entire surface of the pixel region near the surface of the semiconductor substrate 211. The N-type diffusion layer 223 is a contact layer connected to the contact electrode 281, which serves as a cathode and is used to supply a negative voltage for forming the avalanche multiplication region 257. The N-type diffusion layer 223 is formed into a convex shape, with a portion thereof extending toward the contact electrode 281 on the surface of the semiconductor substrate 211.

[0100] The hole accumulation layer 224 is a P-type diffusion layer (P) formed to surround the side and bottom surfaces of the N-well 221 and accumulates holes. Furthermore, the hole accumulation layer 224 is connected to a high-concentration P-type diffusion layer 225, which is electrically connected to a contact electrode 282 serving as the anode of the SPAD 101.

[0101] The high-concentration P-type diffusion layer 225 is a concentrated P-type diffusion layer (P++) formed near the surface of the semiconductor substrate 211 surrounding the periphery of the N-well 221 and constitutes a contact layer for electrically connecting the hole accumulation layer 224 and the contact electrode 282 of the SPAD 101 .

[0102] A pixel separator 259 is formed at the boundary between adjacent pixels of the semiconductor substrate 211, i.e., at the pixel boundary. For example, the pixel separator 259 may consist solely of an insulating layer, or may have a double structure in which the outer side of the tungsten metal layer (the N-well 221 side) is covered with an insulating layer such as SiO2.

[0103] In the sensor-side wiring layer 212 , contact electrodes 281 and 282 , metal wirings 283 and 284 , contact electrodes 285 and 286 , and metal wirings 287 and 288 are formed.

[0104] The contact electrode 281 connects the N-type diffusion layer 223 and the metal wiring 283 , and the contact electrode 282 connects the high-concentration P-type diffusion layer 225 and the metal wiring 284 .

[0105] In a planar region, the metal wiring 283 is formed wider than the avalanche multiplying region 257 to at least cover the avalanche multiplying region 257. The metal wiring 283 may have a structure that reflects light transmitted through the pixel region of the semiconductor substrate 211 toward the semiconductor substrate 211.

[0106] In a planar region, the metal wiring 284 is formed to overlap with the high-concentration P-type diffusion layer 225 so as to surround the outer periphery of the metal wiring 283 .

[0107] Contact electrode 285 connects metal wiring 283 and metal wiring 287 , and contact electrode 286 connects metal wiring 284 and metal wiring 288 .

[0108] On the other hand, the second substrate 202 includes a semiconductor substrate 311 made of silicon or the like and a wiring layer 312 (logic-side wiring layer 312 ).

[0109] In the drawing, a plurality of MOS transistors Tr (Tr1, Tr2, etc.) are formed on the front surface side of an upper semiconductor substrate 311, and a logic-side wiring layer 312 is formed at the same time.

[0110] The logic-side wiring layer 312 has metal wirings 331 and 332 , metal wirings 333 and 334 , and contact electrodes 335 and 336 .

[0111] The metal wiring 331 is electrically and physically connected to the metal wiring 287 of the sensor-side wiring layer 212 via a metal bond such as Cu-Cu. The metal wiring 332 is electrically and physically connected to the metal wiring 288 of the sensor-side wiring layer 212 via a metal bond such as Cu-Cu.

[0112] Contact electrode 335 connects metal wiring 331 and metal wiring 333 , and contact electrode 336 connects metal wiring 332 and metal wiring 334 .

[0113] The logic-side wiring layer 312 further includes a multilayer metal wiring 341 between the layers of the metal wirings 333 and 334 and the semiconductor substrate 311 .

[0114] On the second substrate 202 , logic circuits corresponding to the pixel driving unit 71 , the MUX 73 , the time measuring unit 74 , the signal processing unit 75 , etc. are formed by a plurality of MOS transistors Tr formed on the semiconductor substrate 311 and the multilayer metal wiring 341 .

[0115] For example, a power supply voltage VE applied to the N-type diffusion layer 223 is supplied to the N-type diffusion layer 223 by the logic circuit formed on the second substrate 202 via the metal wiring 333, the contact electrode 335, the metal wirings 331 and 287, the contact electrode 285, the metal wiring 283, and the contact electrode 281. A power supply voltage VA is supplied to the high-concentration P-type diffusion layer 225 via the metal wiring 334, the contact electrode 336, the metal wirings 332 and 288, the contact electrode 286, the metal wiring 284, and the contact electrode 282. Furthermore, when a P-well is formed in which the impurity concentration of the semiconductor substrate 211 is controlled to be p-type, instead of the N-well 221, the voltage applied to the N-type diffusion layer 223 becomes the power supply voltage VA, and the voltage applied to the high-concentration P-type diffusion layer 225 becomes the power supply voltage VE.

[0116] The cross-sectional structure of the pixel 81M for measurement is constructed as described above. The SPAD 101 serving as a light-receiving element includes an N-well 221 of a semiconductor substrate 211, a P-type diffusion layer 222, an N-type diffusion layer 223, a hole accumulation layer 224, and a high-concentration P-type diffusion layer 225. The hole accumulation layer 224 is connected to a contact electrode 282 serving as an anode, and the N-type diffusion layer 223 is connected to a contact electrode 281 serving as a cathode.

[0117] At least one layer of metal wiring 283, 284, 287, 288, 331 to 334, or 341 serving as a light shielding member is disposed between the semiconductor substrate 211 of the first substrate 201 and the semiconductor substrate 311 of the second substrate 202 throughout the entire area in the planar direction of the pixel 81M. Therefore, even if light is emitted by hot carriers in the MOS transistor Tr in the semiconductor substrate 311 of the second substrate 202, the light does not reach the N-well 221 and N-type region 258 of the semiconductor substrate 211 serving as the photoelectric conversion region.

[0118] In pixel 81M, SPAD 101, which serves as a light-receiving element, has a light-receiving surface formed by the plane of N-well 221 and hole accumulation layer 224, and MOS transistor Tr, which serves as a light-emitting source for hot-carrier emission, is provided on the side opposite to the light-receiving surface of SPAD 101. Furthermore, metal wiring 283 and metal wiring 341, which serve as light-shielding members, are provided between SPAD 101, which serves as a light-receiving element, and MOS transistor Tr, which serves as a light-emitting source, so that light emitted by hot carriers does not reach N-well 221 or N-type region 258 of semiconductor substrate 211, which serves as a photoelectric conversion region.

[0119] The pixel structure of the dummy pixel 81D is the same as that of the measurement pixel 81M.

[0120] Figure 6B shows a cross-sectional view of a pixel 81R for reference.

[0121] exist Figure 6 In B, with Figure 6 The corresponding parts of A are given the same reference numerals, and their descriptions are appropriately omitted.

[0122] exist Figure 6 In the cross-sectional structure of the reference pixel 81R shown in FIG. Figure 6 The difference of the measurement pixel 81M shown in FIG. 8A is that a light guide portion 361 for transmitting light (photons) generated by hot carrier luminescence is provided between the SPAD 101 as a light receiving element and the MOS transistor Tr as a light source performing hot carrier luminescence.

[0123] That is, in a portion of the entire area in the planar direction between the semiconductor substrate 211 of the first substrate 201 and the semiconductor substrate 311 of the second substrate 202 of the pixel 81R, there is a region where none of the metal wirings 283, 284, 287, 288, 331 to 334 and 341 for shielding light are formed, and the metal wiring forms a light-guiding portion 361 for propagating light in the stacking direction of the metal wiring.

[0124] Therefore, if hot carrier luminescence is generated in the MOS transistor Tr1 formed at a position at least partially overlapping the light guide portion 361 in the planar direction, the SPAD 101 of the pixel 81R can receive the light generated by the hot carrier luminescence that has passed through the light guide portion 361 and output a detection signal (pixel signal). In addition, even if all metal wirings 283, 341, etc. are not completely open as described above, the light guide portion 361 only needs to be open to the extent that light can pass through.

[0125] In addition, a light shielding member (light shielding layer) 362 is formed on the light-receiving surface side of pixel 81R, that is, on the upper surface of hole accumulation layer 224, so as to cover the light-receiving surface of hole accumulation layer 224. Light shielding member 362 blocks interfering light and the like that is incident from the light-receiving surface side. As described above, since the influence of interfering light and the like can be removed by the histogram generation process, light shielding member 362 is not essential and can be omitted.

[0126] The MOS transistor Tr1 that emits light that propagates through the light guiding portion 361 and reaches the photoelectric conversion region of the pixel 81R may be a MOS transistor Tr1 provided as a light source as a circuit element not included in the measurement pixel 81M, or may be a MOS transistor formed in the pixel 81M.

[0127] Therefore, when MOS transistor Tr1 is provided exclusively as a light source in reference pixel 81R, the circuits formed in the pixel region on second substrate 202 differ between reference pixel 81 and measurement pixel 81M. In this case, MOS transistor Tr1 provided exclusively as a light source corresponds to, for example, a circuit for controlling the light source.

[0128] For example, the timing at which MOS transistor Tr1, which is specifically configured as a light source, emits light can be set to coincide with the timing at which light emitting section 121 of light source 32 emits light. In this case, for example, by making the timing at which reference pixel 81R receives light from the light source (MOS transistor Tr1) the reference for zero distance, the distance calculated from the timing at which measurement pixel 81M receives light can be calibrated. In other words, reference pixel 81R can be used to calibrate distance data.

[0129] In addition, for example, the reference pixel 81R can be used to confirm the appropriateness of the voltage applied to the SPAD 101. In this case, in the pixel 81R, the MOS transistor Tr1 set as a light source is made to emit light, and the cathode voltage VS of the SPAD 101 during the quenching operation is confirmed, that is, Figure 4 The cathode voltage VS at time t2 can be used to adjust the anode voltage VA.

[0130] On the other hand, when the MOS transistor Tr1 serving as the light source is formed in the measurement pixel 81M, the circuit formed in the pixel region on the second substrate 202 may be the same in the reference pixel 81 and the measurement pixel 81M.

[0131] In addition, the light-emitting source of the reference pixel 81R is not limited to the MOS transistor, and may be other circuit elements such as a diode or a resistor.

[0132] As described above, the light receiving device 52 comprises a laminated structure formed by bonding the first substrate 201 and the second substrate 202 together. However, the light receiving device 52 may be formed from a single substrate (semiconductor substrate) or from a laminated structure of three or more substrates. Furthermore, while the light receiving surface of the first substrate 201, which has the sensor-side wiring layer 212 formed on the opposite side of the front surface, is a back-type light receiving sensor structure, a surface-type light receiving sensor structure may also be employed.

[0133] <6. Comparative Example>

[0134] Figure 7 As a comparative example to be compared with the configurations of the light source 32 and the pixel array 72 of the distance measuring system 11 , a configuration example of a light source and a pixel array in another distance measuring system is shown.

[0135] Figure 7The light source 40 includes a plurality of light emitting sections 411M and 411R arranged in a matrix. The light emitting sections 411M and 411R are similar to the light emitting section 121 of the light source 32 and are composed of, for example, vertical cavity surface emitting lasers (VCSELs).

[0136] and Figure 5 Compared to the configuration of the light source 32 of the distance measuring system 11 shown, the light emitting section 411M corresponds to the light emitting section 121, and the light source 401 includes a light emitting section 411R in addition to the light emitting section 121. The light emitting section 411R is a reference light emitting section 411 provided to illuminate the reference pixel 412R of the pixel array 402.

[0137] exist Figure 7 In the pixel array 402, the measurement pixel 412M, the reference pixel 412R, and the dummy pixel 412D are arranged in the same manner as Figure 5 However, the pixel structures of the pixels 412M, 412R, and 412D are configured to be the same as those of the pixel array 72. Figure 6 The structure of the measurement pixel 81M shown in A is the same.

[0138] That is, the reference pixel 412R, like the measurement pixel 412M, has a light-shielding component between the SPAD 101 and the MOS transistor Tr serving as the light source, which blocks the light emitted by hot carriers from reaching the photoelectric conversion region, thereby receiving light irradiated from the reference light-emitting portion 411R from the light-receiving surface side.

[0139] In this composition, Figure 5 Compared to the distance measurement system 11 shown, the light emitting unit 411R is additionally required for the reference pixel 412R. This increases the mounting area of ​​the light emitting unit 411R and the power required to drive the light emitting unit 411R, thereby increasing power consumption. Furthermore, the optical axis must be adjusted so that the light emitted from the light emitting unit 411R is received by the reference pixel 412R, and optical axis deviation is minimized.

[0140] In contrast, the configuration of the light source 32 and pixel array 72 of the ranging system 11 eliminates the need for the light emitting unit 411R for the reference pixel 412R. This not only reduces power consumption but also eliminates the need for adjustment of optical axis offset. Furthermore, the light source is provided within the pixel region of the reference pixel 81R, specifically on the side opposite to the light-receiving surface of the SPAD 101, and a light guide 361 for transmitting light is provided, enabling reliable light reception.

[0141] <7. Other Pixel Arrangement Examples>

[0142] Figure 82 is a cross-sectional view showing another example of pixel arrangement in the pixel array 72 .

[0143] exist Figure 8 In the cross-sectional view, Figure 6 Corresponding parts are given the same reference numerals, but are shown in a more simplified manner. Figure 6 The structure shown in FIG2 is the same as that shown in FIG2 , and some reference numerals are omitted.

[0144] exist Figure 5 In the arrangement example of the pixel array 72 shown in , the reference pixel 81R is arranged in a pixel row or pixel column away from the measurement pixel 81M in a manner that sandwiches the virtual pixel 81D therebetween, but the reference pixel 81R and the measurement pixel 81M may also be arranged in the same pixel row or pixel column.

[0145] Figure 8 The cross-sectional view shows pixels 81 arranged in one pixel row or pixel column.

[0146] like Figure 8 As shown, reference pixel 81R and measurement pixel 81M can be arranged in the same pixel row or pixel column. Even in this case, it is desirable to arrange dummy pixel 81D between reference pixel 81R and measurement pixel 81M, with the dummy pixel 81D sandwiched therebetween. This can suppress the effect on measurement pixel 81M even if light from MOS transistor Tr, the light source of reference pixel 81R, leaks into adjacent pixel 81. Alternatively, dummy pixel 81D between reference pixel 81R and measurement pixel 81M can be omitted.

[0147] <8. Example of using the ranging system>

[0148] This technology is not limited to range-finding systems. Specifically, it can be applied to all electronic devices, including smartphones, tablets, mobile phones, personal computers, game consoles, television receivers, wearable devices, digital still cameras, and digital video cameras. The imaging unit 41 may be a packaged assembly in which the lens 51 and light receiving device 52 are packaged together, or the lens 51 and light receiving device 52 may be separate components, with only the light receiving device 52 being a single chip.

[0149] Figure 9 1 and 2 are diagrams showing examples of use of the distance measuring system 11 or the light receiving device 52 .

[0150] The distance measuring system 11 described above can be used in various situations of sensing light such as visible light, infrared light, ultraviolet light, and X-rays, for example, as follows.

[0151] Devices that capture images for viewing, such as digital cameras and mobile devices with camera functions

[0152] Traffic devices such as on-vehicle sensors that capture images of the front, rear, surroundings, and interior of a vehicle for safe driving, such as automatic stopping, and driver status recognition; surveillance cameras that monitor moving vehicles and roads; and distance sensors that measure distances between vehicles.

[0153] · To capture user gestures and operate devices based on them, for home appliances such as TVs, refrigerators, and air conditioners

[0154] Endoscopes, devices for angiography using infrared light, and other medical and health care devices

[0155] ・Security devices such as surveillance cameras for security purposes and cameras for personal authentication purposes

[0156] ・Device for beauty use, such as a skin measuring device that takes pictures of the skin and a microscope that takes pictures of the scalp

[0157] Sports cameras, wearable cameras, and other sports devices

[0158] Agricultural equipment such as cameras used to monitor the status of fields and crops

[0159] <9. Application Examples to Mobile Objects>

[0160] The technology disclosed herein (the present technology) can be applied to a variety of products. For example, the technology disclosed herein can be implemented as a device mounted on any type of mobile object, including automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, and robots.

[0161] Figure 10 This is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0162] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. Figure 10 In the illustrated example, vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an exterior information detection unit 12030, an interior information detection unit 12040, and an integrated control unit 12050. Furthermore, as functional components of integrated control unit 12050, a microcomputer 12051, an audio and video output unit 12052, and an in-vehicle network I / F (interface) 12053 are illustrated.

[0163] The drive system control unit 12010 controls the operation of devices related to the vehicle's drive system according to various programs. For example, the drive system control unit 12010 functions as a control device for a drive force generating device such as an internal combustion engine or a drive motor that generates the vehicle's drive force; a drive force transmission mechanism that transmits the drive force to the wheels; a steering mechanism that adjusts the vehicle's steering angle; and a braking device that generates the vehicle's braking force.

[0164] The body system control unit 12020 controls the operation of various devices installed on the vehicle according to various programs. For example, the body system control unit 12020 functions as a controller for the keyless entry system, smart key system, power windows, and various lights such as the headlights, taillights, brake lights, signal lights, and fog lights. In these cases, radio waves transmitted from a portable device that replaces a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door locks, power windows, lights, and other devices.

[0165] The vehicle exterior information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, the camera unit 12031 is connected to the vehicle exterior information detection unit 12030. The vehicle exterior information detection unit 12030 causes the camera unit 12031 to capture images outside the vehicle and receive the captured images. The vehicle exterior information detection unit 12030 can also perform object detection processing such as people, cars, obstacles, signs, or text on the road, or distance detection processing based on the received images.

[0166] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 can be visible light or invisible light such as infrared.

[0167] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the driver's state is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures the driver's image. Based on the detection information input from the driver state detection unit 12041, the in-vehicle information detection unit 12040 can calculate the driver's level of fatigue or concentration, and can also determine whether the driver is dozing off.

[0168] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 performs coordinated control for the purpose of implementing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or mitigation, vehicle-to-vehicle distance-based following, speed maintenance, collision warning, or lane departure warning.

[0169] In addition, the microcomputer 12051 controls the driving force generating device, steering mechanism, or braking device based on the information around the vehicle obtained by the external information detection unit 12030 or the internal information detection unit 12040, thereby enabling coordinated control for the purpose of automatic driving, etc., which allows the vehicle to travel automatically without relying on the driver's operation.

[0170] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on the information outside the vehicle acquired by the vehicle exterior information detection unit 12030. For example, the microcomputer 12051 can control the headlights based on the position of the preceding vehicle or oncoming vehicle detected by the vehicle exterior information detection unit 12030, thereby performing coordinated control for the purpose of preventing glare, such as switching from high beam to low beam.

[0171] The audio and video output unit 12052 sends an output signal of at least one of audio and video to an output device that can visually or auditorily notify the occupants of the vehicle or the outside of the vehicle of information. Figure 10 In the example of FIG, as the output device, an audio speaker 12061, a display portion 12062, and an instrument panel 12063 are exemplified. The display portion 12062 may include, for example, at least one of an in-vehicle display and a head-up display.

[0172] Figure 11 This is a diagram showing an example of the installation position of the imaging unit 12031.

[0173] exist Figure 11 In the figure, the vehicle 12100 includes imaging units 12101 , 12102 , 12103 , 12104 , and 12105 as the imaging unit 12031 .

[0174] Cameras 12101, 12102, 12103, 12104, and 12105 are located, for example, on the front of the vehicle 12100, in the rearview mirrors, rear bumper, rear doors, and above the front windshield inside the vehicle cabin. Camera 12101 on the front of the vehicle and camera 12105 on the above-mentioned front windshield inside the vehicle cabin primarily capture images of the front of the vehicle 12100. Cameras 12102 and 12103 on the rearview mirrors primarily capture images of the sides of the vehicle 12100. Camera 12104 on the rear bumper or rear door primarily captures images of the rear of the vehicle 12100. The images captured by cameras 12101 and 12105 are primarily used to detect vehicles or pedestrians ahead, obstacles, traffic lights, traffic signs, lanes, and the like.

[0175] in addition, Figure 11 The figure shows an example of the imaging ranges of the imaging units 12101 to 12104. The imaging range 12111 represents the imaging range of the imaging unit 12101 located at the front of the vehicle, the imaging ranges 12112 and 12113 represent the imaging ranges of the imaging units 12102 and 12103 located at the rearview mirrors, respectively, and the imaging range 12114 represents the imaging range of the imaging unit 12104 located at the rear bumper or rear door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 can be obtained.

[0176] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of multiple imaging elements, or an imaging element having pixels for phase difference detection.

[0177] For example, based on the distance information obtained from imaging units 12101 to 12104, microcomputer 12051 calculates the distance to each three-dimensional object within imaging range 12111 to 12114 and the temporal variation of that distance (relative speed to vehicle 12100). Specifically, microcomputer 12051 can identify the closest three-dimensional object on the path of vehicle 12100 and, as the preceding vehicle, the three-dimensional object traveling in the same direction as vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, microcomputer 12051 can set a predetermined inter-vehicle distance in front of the preceding vehicle and perform automatic braking control (including follow-up stop control) and automatic acceleration control (including follow-up advance control). This enables coordinated control aimed at, for example, autonomous driving, which allows the vehicle to travel independently of the driver.

[0178] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 classifies 3D object data related to three-dimensional objects into categories such as two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, and utility poles, and extracts these data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 as those visible to the driver and those difficult to see. Furthermore, the microcomputer 12051 determines a collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk exceeds a set value, indicating a potential collision, the microcomputer 12051 outputs a warning to the driver via the audio speaker 12061 or display unit 12062, or initiates forced deceleration or evasive steering via the drive system control unit 12010, thereby providing driving assistance to avoid collisions.

[0179] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can identify pedestrians by determining whether a pedestrian exists in images captured by the imaging units 12101 to 12104. This pedestrian identification is performed, for example, by extracting feature points from images captured by the imaging units 12101 to 12104, which are infrared cameras, and performing pattern matching on a series of feature points representing the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian exists in the images captured by the imaging units 12101 to 12104 and identifies the pedestrian, the audio and video output unit 12052 controls the display unit 12062 to display a square outline for emphasis overlaid on the identified pedestrian. Alternatively, the audio and video output unit 12052 may control the display unit 12062 to display an icon representing the pedestrian at a desired location.

[0180] The above describes an example of a vehicle control system to which the technology of the present disclosure can be applied. The technology of the present disclosure can be applied to the above-described imaging unit 12031 and the like. Specifically, for example, Figure 1 The ranging system 11 can be applied to the imaging unit 12031. The imaging unit 12031 is, for example, a laser radar, which detects objects around the vehicle 12100 and the distance to those objects. By applying the technology disclosed herein to the imaging unit 12031, the accuracy of detecting objects around the vehicle 12100 and the distance to those objects are improved. As a result, for example, a vehicle collision warning can be issued at an appropriate time, thereby preventing traffic accidents.

[0181] In this specification, a system refers to a collection of multiple components (devices, components (parts), etc.), and it does not matter whether all components are housed in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, as well as a single device housing multiple components in a single housing, are both systems.

[0182] In addition, the embodiment of the present technology is not limited to the above-mentioned embodiment, and various changes can be made without departing from the gist of the present technology.

[0183] In addition, the effects described in this specification are merely examples and are not limiting, and there may be effects other than those described in this specification.

[0184] In addition, the present technology can adopt the following configurations. (1)

[0186] A light receiving device includes a plurality of pixels, wherein the plurality of pixels have:

[0187] a light receiving element having a light receiving surface; and

[0188] a light source, arranged on a side opposite to the light receiving surface relative to the light receiving element,

[0189] The plurality of pixels comprises:

[0190] A first pixel having a light shielding member disposed between the light receiving element and the light source; and

[0191] The second pixel includes a light-guiding portion for transmitting photons between the light-receiving element and the light-emitting source. (2)

[0193] According to the light receiving device described in (1), the second pixel further includes a light shielding member, and the light shielding member covers the light receiving surface of the light receiving element. (3)

[0195] According to the light receiving device described in (1) or (2), the light emitting source of the second pixel emits light at the same timing as the timing of irradiating the reflected light received by the light receiving element of the first pixel. (4)

[0197] The light receiving device according to any one of (1) to (3) is formed by bonding two or more substrates including a first substrate and a second substrate.

[0198] The light receiving element is formed on the first substrate,

[0199] The light source is formed on the second substrate. (5)

[0201] According to the light receiving device described in (4), in the circuit within the pixel region of the second substrate, the first pixel and the second pixel are different. (6)

[0203] According to the light receiving device described in (5), the circuit that is different between the first pixel and the second pixel is a circuit that controls the light source formed in the second pixel. (7)

[0205] According to the light receiving device described in (4), in the circuit within the pixel region of the second substrate, the first pixel and the second pixel are identical. (8)

[0207] According to the light receiving device according to any one of (1) to (7), the light receiving element is a SPAD. (9)

[0209] According to the light receiving device described in (8), the signal of the pixel is used for any one of distance measurement, calibration of distance data, and confirmation of the suitability of the voltage applied to the SPAD. (10)

[0211] According to the light receiving device described in (9), in confirming the suitability of the voltage applied to the SPAD, the voltage applied to the SPAD of the second pixel is measured. (11)

[0213] The light receiving device according to (10) controls the anode voltage of the SPAD based on the measured applied voltage of the SPAD. (12)

[0215] The light receiving device according to any one of (1) to (11) further includes a third pixel not used for distance measurement between the first pixel and the second pixel in the planar direction. (13)

[0217] According to the light receiving device described in (12), the third pixel is a pixel that is not driven. (14)

[0219] In the light-receiving device described in (12), the third pixel is a pixel driven for internal voltage monitoring. (15)

[0221] In the light receiving device according to any one of (1) to (14), the first pixels are arranged in N1×N2 (N1 and N2 are integers greater than or equal to 1). (16)

[0223] In the light-receiving device according to any one of (1) to (15), the second pixels are arranged in M1×M2 (M1 and M2 are integers greater than or equal to 1). (17)

[0225] According to any one of (1) to (16) of the light receiving device, the light emitting source is constituted by any one of a transistor, a diode, and a resistor. (18)

[0227] A ranging system, comprising:

[0228] an illumination device that emits illumination light; and

[0229] a light receiving device for receiving reflected light from the irradiated light,

[0230] The light receiving device includes a plurality of pixels, and the plurality of pixels have:

[0231] a light receiving element having a light receiving surface; and

[0232] a light source, arranged on a side opposite to the light receiving surface relative to the light receiving element,

[0233] The plurality of pixels comprises:

[0234] A first pixel having a light shielding member disposed between the light receiving element and the light source; and

[0235] The second pixel includes a light-guiding portion for transmitting photons between the light-receiving element and the light-emitting source.

[0236] Description of Reference Numerals

[0237] 11…ranging system; 21…illumination device; 22…photographing device; 31…illumination control unit; 32…light source; 41…photographing unit; 42…control unit; 52…light receiving device; 71…pixel driving unit; 72…pixel array; 73…MUX; 74…time measurement unit; 75…signal processing unit; 76…input / output unit; 81 (81R, 81M, 81D)…pixel; 101…SPAD; 102…transistor; 103…switch; 104…inverter; 201…first substrate; 202…second substrate; 211…semiconductor substrate; Tr…MOS transistor; 361…light guiding unit; 362…light shielding component.

Claims

1. A light receiving device, characterized in that: The light receiving device is configured to receive reflected light from a subject, wherein the light receiving device includes a plurality of pixels, each of which has: a light receiving element having a light receiving surface for the reflected light to be incident on; as well as a light source, arranged on a side opposite to the light receiving surface relative to the light receiving element, The plurality of pixels comprises: A first pixel having a light shielding member disposed between the light receiving element and the light source; as well as The second pixel includes a light-guiding portion for transmitting photons between the light-receiving element and the light source, and the light source is provided in a pixel region of the second pixel.

2. The light receiving device according to claim 1, wherein The second pixel further includes a light shielding member that covers a light receiving surface of the light receiving element.

3. The light receiving device according to claim 1, wherein The light source of the second pixel emits light at the same timing as the timing of irradiating the reflected light received by the light receiving element of the first pixel.

4. The light receiving device according to claim 1, wherein The light receiving device is formed by bonding two or more substrates including a first substrate and a second substrate. The light receiving element is formed on the first substrate, The light source is formed on the second substrate.

5. The light receiving device according to claim 4, wherein In a circuit within a pixel region of the second substrate, the first pixel and the second pixel are different.

6. The light receiving device according to claim 5, wherein The circuit that is different between the first pixel and the second pixel is a circuit for controlling the light source formed in the second pixel.

7. The light receiving device according to claim 4, wherein In a circuit within a pixel region of the second substrate, the first pixel and the second pixel are identical.

8. The light receiving device according to claim 1, wherein The light receiving element is a single photon avalanche diode.

9. The light receiving device according to claim 8, wherein The signal from the pixel is used for any of ranging, calibration of distance data, and confirmation of the suitability of the voltage applied to the single-photon avalanche diode.

10. The light receiving device according to claim 9, wherein In checking the suitability of the voltage applied to the single-photon avalanche diode, the voltage applied to the single-photon avalanche diode of the second pixel is measured.

11. The light receiving device according to claim 10, wherein Based on the measured applied voltage of the single-photon avalanche diode, the anode voltage of the single-photon avalanche diode is controlled.

12. The light receiving device according to claim 1, wherein In the planar direction, a third pixel not used for distance measurement is provided between the first pixel and the second pixel.

13. The light receiving device according to claim 12, wherein: The third pixel is a pixel that is not driven.

14. The light receiving device according to claim 12, wherein The third pixel is a pixel driven for internal voltage monitoring.

15. The light receiving device according to claim 1, wherein The first pixels are arranged in an N1×N2 array, where N1 and N2 are integers greater than or equal to 1.

16. The light receiving device according to claim 1, wherein The second pixels are arranged in M1×M2, where M1 and M2 are integers greater than or equal to 1.

17. The light receiving device according to claim 1, wherein The light emitting source is composed of any one of a transistor, a diode, and a resistor.

18. A distance measurement system, characterized in that: include: an illumination device for emitting illumination light; as well as a light receiving device for receiving reflected light from the irradiated light, The light receiving device includes a plurality of pixels, and the plurality of pixels have: A light receiving element having a light receiving surface; as well as a light source, arranged on a side opposite to the light receiving surface relative to the light receiving element, The plurality of pixels comprises: A first pixel having a light shielding member disposed between the light receiving element and the light source; as well as The second pixel includes a light-guiding portion for transmitting photons between the light-receiving element and the light source, and the light source is provided in a pixel region of the second pixel.

Images