Light detection device and ranging system

Abstract

The light detecting device includes: an avalanche photodiode in which a first fixed voltage is applied to one of an anode region and a cathode region to multiply carriers generated by incident photons; a protection circuit electrically connected in series to the other of the anode region and the cathode region and including a resistive element (R) to protect an internal circuit from overcurrent; and a first electrical conductor (1141) electrically connected in parallel to the resistive element (R).

Description

Technical Field

[0001] This disclosure relates to optical detection devices and ranging systems. Background Technology

[0002] Patent document 1 discloses an optical receiving device and a ranging device. An optical receiving device includes an optical receiving element that generates a signal in response to the input of photons. This optical receiving element is a light detection element. For example, a single-photon avalanche diode (SPAD) element is used as the optical receiving element. The ranging device includes a light receiving device. This ranging device measures the time of flight (ToF) from when light is emitted from a light source toward the ranging target (subject) to when the light reflected from the target returns. In other words, the ranging device measures the distance to the ranging target. For example, in terms of light, a highly directional laser is used. Reference List Patent documents

[0003] Patent Document 1: US2023 / 0145695A1 Summary of the Invention

[0004] The optical receiving device or optical receiving device and ranging device disclosed in Patent Document 1 includes a protection circuit. Similar to direct laser irradiation, when a SPAD is exposed to an unexpectedly large amount of light, it experiences a significant impact on photoelectric conversion, leading to a substantial decrease in internal impedance. This can apply excessively high voltage to the readout circuitry, which reads the signal generated by the photoelectric conversion of the SPAD elements. The protection circuitry includes resistive elements to mitigate the excessive voltage applied to the readout circuitry. It is anticipated that the optical receiving device and ranging device will further improve the tolerance of the resistive element to excessive voltage and improve the characteristics of the protection circuit.

[0005] According to a first embodiment of this disclosure, the photodetector includes: an avalanche photodiode, wherein a first fixed voltage is applied to one of the anode region and the cathode region to multiply the charge carriers generated by the incident photons; a protection circuit including a resistive element electrically connected in series with the other of the anode region and the cathode region to protect the internal circuit from overcurrent; and a first electrical conductor electrically connected in parallel with the resistive element.

[0006] In the optical detection device according to the second embodiment of this disclosure, the first electrical conductor of the optical detection device according to the first embodiment is configured to be opposite to the second electrical conductor, an insulator is inserted between the first electrical conductor and the second electrical conductor, and the second electrical conductor is electrically connected to a second fixed voltage. Furthermore, in the optical detection device, the first electrical conductor, the insulator, and the second electrical conductor constitute a capacitor element to protect the resistive element from overcurrent.

[0007] In the optical detection device according to the third embodiment, the resistive element of the optical detection device according to the first embodiment comprises polysilicon, metal, or insulated gate field-effect transistor.

[0008] In the photodetector according to the fourth embodiment of this disclosure, the resistive element of the photodetector according to the first embodiment has the same or different polarity as the other of the anode region and the cathode region of the avalanche photodiode.

[0009] According to the fifth embodiment of this disclosure, the ranging system includes an optical detection device and a circuit device. The optical detection device includes: an avalanche photodiode, wherein a first fixed voltage is applied to one of the anode and cathode regions to multiply the charge carriers generated by the incident photons; a protection circuit including a resistive element electrically connected in series with the other of the anode and cathode regions to protect the internal circuitry from overcurrent; and a first electrical conductor electrically connected in parallel with the resistive element. The circuit device includes: an internal circuit electrically connected to the avalanche photodiode via the protection circuit, the internal circuit constituting a readout circuit for reading out the multiplied charge carriers; and a time measurement circuit electrically connected to the internal circuit for measuring the time of flight of light. Attached Figure Description

[0010] Figure 1 This is a circuit configuration diagram showing a portion of the optical detection device and ranging system according to a first embodiment of the present disclosure. Figure 2 It is shown Figure 1 The diagram shows the vertical cross-sectional configuration of the optical detection element (optical receiving element) of the optical detection device. Figure 3 It shows the setting Figure 1 A plan view of a portion of the protection circuit in the light detection device shown. Figure 4 This is a plan view showing a portion of the protection circuit provided in the light detection apparatus according to the second embodiment of the present disclosure, the plan view corresponding to Figure 3 . Figure 5 This is a plan view showing a portion of the protection circuit provided in the light detection apparatus according to the third embodiment of the present disclosure, the plan view corresponding to Figure 3 . Figure 6 This is a plan view showing a portion of the protection circuit provided in the light detection apparatus according to the fourth embodiment of the present disclosure, the plan view corresponding to Figure 3 . Figure 7 This is a plan view showing a portion of a protection circuit provided in a light detection apparatus according to a fifth embodiment of the present disclosure, the plan view corresponding to Figure 3 . Figure 8 This is a plan view showing a portion of the protection circuit provided in the light detection apparatus according to the sixth embodiment of the present disclosure, the plan view corresponding to Figure 3 . Figure 9 This is a plan view showing a portion of the protection circuit provided in the light detection apparatus according to the seventh embodiment of the present disclosure, the plan view corresponding to Figure 3 . Figure 10 This is a vertical cross-sectional view showing the optical detection element of the optical detection apparatus according to the eighth embodiment of the present disclosure, the vertical cross-sectional view corresponding to Figure 2 . Figure 11 It is shown Figure 10 The diagram shown is a plan view of a portion of the protection circuit installed in the optical detection device, which corresponds to... Figure 3 . Figure 12 This is a vertical cross-sectional view showing the optical detection element of the optical detection apparatus according to the ninth embodiment of the present disclosure, the vertical cross-sectional view corresponding to Figure 2 . Figure 13 It is shown Figure 12 The diagram shown is a plan view of a portion of the protection circuit installed in the optical detection device, which corresponds to... Figure 3 . Figure 14 This is a vertical cross-sectional view showing the optical detection element of the optical detection apparatus according to the tenth embodiment of the present disclosure, the vertical cross-sectional view corresponding to Figure 2 . Figure 15 This is a circuit diagram showing a portion of the optical detection device and ranging system according to the eleventh embodiment of the present disclosure, the circuit diagram corresponding to Figure 1 . Figure 16 It is shown Figure 15 The diagram shown is a vertical cross-sectional view of the optical detection element of the optical detection device, which corresponds to... Figure 2 . Figure 17This is a circuit diagram showing a portion of the optical detection device and ranging system according to the twelfth embodiment of the present disclosure, the circuit diagram corresponding to Figure 1 . Figure 18 This is a circuit diagram showing a portion of the optical detection device and ranging system according to the thirteenth embodiment of the present disclosure, the circuit diagram corresponding to Figure 1 . Figure 19 This is a circuit diagram illustrating a portion of the optical detection apparatus and ranging system according to the fourteenth embodiment of the present disclosure, the circuit diagram corresponding to Figure 1 . Figure 20 This is a circuit diagram illustrating a portion of the optical detection apparatus and ranging system according to the fifteenth embodiment of the present disclosure, the circuit diagram corresponding to Figure 1 . Figure 21 This is a circuit diagram illustrating a portion of the optical detection apparatus and ranging system according to the sixteenth embodiment of the present disclosure, the circuit diagram corresponding to Figure 1 . Figure 22 It is a block diagram illustrating an example of the schematic configuration of a vehicle control system. Figure 23 This is an example diagram used to illustrate the installation locations of the vehicle exterior information detection unit and the camera unit. Detailed Implementation

[0011] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the descriptions will proceed in the following order. 1. First Embodiment In a first embodiment, a first example of the application of this technology to a light detection device and a ranging system will be described. In this first embodiment, the circuit configuration and apparatus configuration of a light detection device including one or more light detection elements (or light receiving elements or pixels) and a ranging system including the light detection device will be described in detail. At least one of the light detection device or ranging system includes a protection circuit with resistive elements. 2. Second Embodiment In the second embodiment, a second example will be described in which the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the first embodiment is changed. 3. Third embodiment In the third embodiment, a third example will be described in which the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the second embodiment is changed. 4. Fourth Embodiment In the fourth embodiment, a fourth example will be described in which the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the second embodiment is changed. 5. Fifth Embodiment In the fifth embodiment, a fifth example will be described in which the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the fourth embodiment is changed. 6. Sixth Embodiment In the sixth embodiment, a sixth example will be described in which the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the third embodiment is changed. 7. Seventh Embodiment In the seventh embodiment, a seventh example of combining the optical detection device and ranging system according to the fourth embodiment with the optical detection device and ranging system according to the sixth embodiment will be described. 8. Eighth Embodiment In the eighth embodiment, an eighth example will be described in which the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the sixth embodiment is changed. 9. Ninth Embodiment In the ninth embodiment, a ninth example of combining the optical detection device and ranging system according to the fifth embodiment with the optical detection device and ranging system according to the seventh embodiment will be described. The ninth embodiment will be described. 10. Tenth Embodiment In the tenth embodiment, a tenth example will be described in which the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the first embodiment is changed. 11. Eleventh Embodiment In the eleventh embodiment, an eleventh example will be described that modifies the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the first embodiment. 12. Twelfth Embodiment In the twelfth embodiment, a twelfth example will be described that modifies the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the first embodiment. 13. Thirteenth Embodiment In the thirteenth embodiment, a thirteenth example will be described that modifies the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the first embodiment. 14. Fourteenth Embodiment In the fourteenth embodiment, a fourteenth example will be described that modifies the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the first embodiment. 15. Fifteenth Embodiment In the fifteenth embodiment, a fifteenth example will be described that modifies the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the first embodiment. 16. Sixteenth Embodiment In the sixteenth embodiment, a sixteenth example will be described that modifies the configuration of the resistive and capacitive elements of the protection circuit in the optical detection device and ranging system according to the fifteenth embodiment. 17. Examples of applications of moving bodies In the application examples, an example of this technology being applied to a vehicle control system, which is an example of a mobile body control system, will be described. 18. Other embodiments

[0012] <1. First Embodiment> Reference Figures 1 to 3 The light detection device 1 and the ranging system 6 according to the first embodiment of this disclosure are described. Here, the X-arrow direction shown appropriately in the figure indicates the planar direction of the light detection device 1 and the ranging system 6, which are placed on a plane for ease of explanation. The Y-arrow direction indicates another planar direction orthogonal to the X-arrow direction. Additionally, the Z-arrow direction indicates an upward direction orthogonal to both the X and Y-arrow directions. In other words, the X, Y, and Z-arrow directions correspond to the X-axis, Y-axis, and Z-axis directions in the three-dimensional coordinate system, respectively. It should be noted that these directions are provided to facilitate understanding of this disclosure and not to limit the directions related to this technology.

[0013] [Circuit configuration of optical detection device 1 and ranging system 6] (1) Schematic overall configuration of optical detection device 1 and ranging system 6 Figure 1 An example of the circuit configuration of the light detection device 1 and the ranging system 6 according to the first embodiment is shown.

[0014] First, the ranging system 6 using this technology measures the distance to the subject, which is the ranging target. Specifically, the ranging system 6 uses the Time-of-Flight (ToF) method to measure the distance. The ToF method refers to receiving light emitted towards and reflected by the subject, and measuring the time of flight of the light from emission to reception. As a light source, for example, a laser with excellent directivity and a peak wavelength in the near-infrared band is used. The ranging system 6 can also be used as a photon counter.

[0015] Therefore, the ranging system 6 includes a light detection device 1. The light detection device 1 includes one or more light detection elements for receiving light and measuring the distance to the subject. The light detection elements also function as light receiving elements and light receiving pixels.

[0016] The following provides detailed information. like Figure 1 As shown, the ranging system 6 includes at least a light detection device 1. In the first embodiment, the ranging system 6 includes at least a light detection device 1 and a circuit device 5. It should be noted that the ranging system 6 may include a laser oscillation device (not shown), etc., as a device for implementing the ToF method. The laser oscillation device includes a laser source.

[0017] (2) Circuit configuration of optical detection device 1 like Figure 1 As shown, the light detection device 1 is configured as a sensor element or a sensor chip. The light detection device 1 is provided with a pixel 10, which includes an avalanche photodiode 11 used as a light detection element. Figure 1 A single pixel 10 is shown. In reality, the light detection device 1 includes a plurality of pixels 10 arranged in a matrix.

[0018] The avalanche photodiode 11 is a single-photon avalanche diode, capable of multiplying carriers generated by incident photons. In other words, the avalanche photodiode 11 is a single-photon avalanche diode (SPAD). The avalanche photodiode 11 operates in the nonlinear region (in Geiger mode). In other words, the avalanche photodiode 11 is set with a predetermined breakdown voltage and operates at a reverse voltage exceeding that predetermined breakdown voltage.

[0019] The avalanche photodiode 11 has an anode region (anode electrode) electrically connected to an anode power line VLsp. The anode region is supplied with an anode voltage Vsp by the anode power line VLsp. The anode voltage Vsp is a large negative voltage used to induce avalanche multiplication, i.e., a fixed voltage (first fixed voltage) exceeding a predetermined breakdown voltage. For example, the anode voltage is a voltage exceeding -20 V.

[0020] The avalanche photodiode 11 has a cathode region (cathode electrode) connected to a readout circuit 3 via a protection circuit 2 inserted between the cathode region and the readout circuit 3. A cathode voltage clamped by the protection circuit 2 (second protection circuit 22) is applied to the cathode region. For example, the cathode voltage is approximately 3 V supplied by a drive power supply Vd.

[0021] (3) Circuit configuration of the first protection circuit 21 of protection circuit 2 The protection circuit 2 includes a first protection circuit 21 and a second protection circuit 22. In addition to the pixel 10, the first protection circuit 21 is also provided in the light detection device 1. When photons with a light intensity greater than expected are incident on the avalanche photodiode 11, the internal impedance of the avalanche photodiode 11 drops sharply, and an overcurrent flows into the readout circuit 3. The first protection circuit 21 is configured to reduce this overcurrent and protect the readout circuit 3.

[0022] In the first embodiment, the first protection circuit 21 includes a resistive element R and a capacitive element C. A resistor R is electrically connected in series between the avalanche photodiode 11 and the readout circuit 3. Specifically, one end of the resistor R is electrically connected in series to the cathode region of the avalanche photodiode 11. The other end of the resistor R is electrically connected in series to the readout circuit 3. The first protection circuit 21 is positioned closer to the avalanche photodiode 11 than the second protection circuit 22.

[0023] Capacitor C and resistor R are electrically connected in parallel. Details will be provided. One electrode of capacitor C is electrically connected to resistor R. The other electrode of capacitor C is positioned opposite at least one electrode, separated by an insulator (dielectric). This other electrode is electrically connected to a fixed power supply Vc. That is, the other electrode is supplied with a fixed voltage (a second fixed voltage) by the fixed power supply Vc. For example, this fixed voltage is similar to the voltage provided by a standard power supply Vs or a drive power supply Vd. Here, one electrode corresponds to the "first electrical conductor 1141" or a portion thereof according to the present technology (see [link]). Figure 2 and Figure 3 Additionally, another electrode corresponds to the "second electrical conductor 1142" or a portion thereof according to this technology (see...). Figure 2 ).

[0024] When photons with a light intensity greater than the pre-set value are incident on the avalanche photodiode 11, the internal impedance of the avalanche photodiode 11 drops sharply, and an overcurrent flows into the readout circuit 3. The capacitor element C is configured to reduce (absorb) this overcurrent, protect the resistor element R, and increase the tolerance of the resistor element R. In other words, the capacitor element C is configured to increase the tolerance of the resistor element R and protect the first protection circuit 21.

[0025] (4) Circuit configuration of circuit device 5 The circuit device 5 is configured as a circuit element or circuit chip. The circuit device 5 includes a second protection circuit 22 of the protection circuit 2, a readout circuit 3, and a time measurement circuit 4.

[0026] (5) Circuit configuration of the second protection circuit 22 The second protection circuit 22 is disposed between the first protection circuit 21 and the readout circuit 3. The second protection circuit 22 includes a first clamping element Tc1 and a second clamping element Tc2. That is, the second protection circuit 22 is configured to clamp the overcurrent flowing from the second protection circuit 22 to the readout circuit 3 and protect the readout circuit 3.

[0027] The first clamping element Tc1 is implemented using a p-type insulated-gate field-effect transistor (IGFET), which is the first conductivity type. Hereinafter, the insulated-gate field-effect transistor is simply referred to as IGFET. Here, IGFET is used in the sense that it includes both metal-oxide-semiconductor field-effect transistors (MOSFETs) and metal-insulator-semiconductor field-effect transistors (MISFETs). An IGFET includes a pair of main electrodes, a gate insulating film, and a gate electrode. This pair of main electrodes serves as the source and drain electrodes.

[0028] The gate electrode of the first clamping element Tc1 and one of its pair of main electrodes are electrically connected to the other end of the resistive element R of the first protection circuit 21. The other of the pair of main electrodes of the first clamping element Tc1 is electrically connected to the standard power supply Vs. That is, the first clamping element Tc1 is electrically connected in parallel between the second protection circuit 22 and the readout circuit 3. For example, a standard power supply Vs provides 0 V voltage.

[0029] Alternatively, the first clamping element Tc1 can be implemented by a diode element (clamping diode element) electrically connected in parallel between the resistor element R and the second clamping element Tc2. The anode region of the diode element is electrically connected to the standard power supply Vs, and the cathode region is electrically connected to the resistor element R and the second clamping element Tc2. In other words, the diode is configured for reverse connection.

[0030] Similar to the first clamping element Tc1, the second clamping element Tc2 is implemented using a p-type IGFET. One of the pair of main electrodes of the second clamping element Tc2 is electrically connected to the other main electrode of the first clamping element Tc1. The other of the pair of main electrodes of the second clamping element Tc2 is electrically connected to the readout circuit 3. The gate electrode of the second clamping element Tc2 is electrically connected to the standard power supply Vs.

[0031] (6) Circuit configuration of readout circuit 3 The readout circuit 3 includes a first control element T1, a second control element T2, a first output element T3, and a second output element T4.

[0032] In the readout circuit 3, the first control element T1 is used as a quenching element and is implemented by a p-type IGFET. One of the pair of main electrodes of the first control element T1 is electrically connected to the drive power supply Vd via a galvanometer (not labeled in the figure), which is inserted between one of the main electrodes of the first control element T1 and the drive power supply Vd. The other of the pair of main electrodes of the first control element T1 is electrically connected to the second protection circuit 22, the second control element T2, the first output element T3, and the second output element T4. The gate electrode of the first control element T1 is input with an enable signal EN.

[0033] When a low-level enable signal EN is input, the first control element T1 enters the conducting state and provides a driving voltage from the driving power supply Vd to the avalanche photodiode 11. That is, the first control element T1 outputs avalanche current, and the readout circuit 3 enters the reset state.

[0034] The second control element T2 is implemented by an n-type IGFET with a second conductivity type opposite to the first conductivity type. One of the pair of main electrodes of the second control element T2 is electrically connected to a standard power supply Vs. The other of the pair of main electrodes of the second control element T2 is electrically connected to the second protection circuit 22, the first control element T1, the first output element T3, and the second output element T4. The gate electrode of the second control element T2 is fed by an input signal xEN. The signal xEN is inverted compared to the enable signal EN. When a high-level signal xEN is input, the second control element T2 enters the conducting state. That is, the standard power supply Vs provides a standard voltage to the cathode of the avalanche photodiode 11, and the readout circuit 3 enters the working state.

[0035] The first output element T3 and the second output element T4 constitute a complementary output circuit. The first output element T3 is implemented using a p-type IGFET. One of the pair of main electrodes of the first output element T3 is electrically connected to the drive power supply Vd. The other of the pair of main electrodes of the first output element T3 is electrically connected to the time measurement circuit 4. The gate electrode of the first output element T3 is electrically connected to the other of the respective main electrodes of the first control element T1 and the second control element T2. When a low-level signal is input to the gate electrode in response to the output of avalanche photodiode 11, the first output element T3 enters the conducting state. This causes the readout circuit 3 to output a high-level readout signal to the time measurement circuit 4. When a high-level signal is input to the gate electrode, the first output element T3 enters the non-conducting state.

[0036] The second output element T4 is implemented using an n-type IGFET. One of the pair of main electrodes of the second output element T4 is electrically connected to a standard power supply Vs. The other of the pair of main electrodes of the second output element T4 is electrically connected to the time measurement circuit 4. In a similar manner to the gate electrode of the first output element T3, the gate electrode of the second output element T4 is electrically connected to the other of the respective main electrodes of the first control element T1 and the second control element T2. When a low-level signal is input to the gate electrode in response to the output of avalanche photodiode 11, the second output element T4 enters the conducting state. This causes the readout circuit 3 to output a low-level readout signal to the time measurement circuit 4. When a high-level signal is input to the gate electrode, the second output element T4 enters the non-conducting state.

[0037] (7) Circuit configuration of time measurement circuit 4 The output of the time measurement circuit 4 is electrically connected to the output of the readout circuit 3. The output of the readout circuit 3 is output to the time measurement circuit 4 as the output of the avalanche photodiode 11 (the output of pixel 10). Based on the output of the avalanche photodiode 11, the time measurement circuit 4 measures the flight time of light emitted towards the subject (range target), reflected by the subject, and returned.

[0038] In the first embodiment, the time measurement circuit 4 is configured as a hardware configuration. Alternatively, the time measurement circuit 4 may include an input circuit, an output circuit, a central processing unit (CPU), a storage unit, etc., and may be configured as a software configuration.

[0039] [The configuration of the optical detection device 1 and the ranging system 6] (1) Vertical cross-section configuration of optical detection device 1 Figure 2 An example of a vertical cross-section of a light detection device 1 including pixels 10 is shown. The light detection device 1 is stacked on a separately manufactured circuit device 5. The stacked light detection device 1 and the circuit device 5 constitute a ranging system 6.

[0040] like Figure 3 As shown, when viewed along the Y-arrow direction (hereinafter referred to as "in the side view"), the photodetector 1 is configured using a substrate 101 as a base structure. For example, in the first embodiment, the substrate 101 is formed from a single-crystal silicon (Si) substrate doped with n-type impurities of low impurity density. Here, substrate 101 corresponds to the "first substrate" according to the present technology.

[0041] A pixel 10, including an avalanche photodiode 11, is disposed in the substrate 101. In a side view, an insulating separator 102 is disposed in the region surrounding the side of the pixel 10 in the substrate 101. The insulating separator 102 is configured to physically isolate the pixel 10 from other pixels 10 (not shown) adjacent to it in the X and Y arrow directions, and to electrically and optically isolate the avalanche photodiodes 11 from each other.

[0042] (2) Composition of insulating separator 102 Here, the insulating separator 102 includes a separation trench 102A and an insert 102B. Details will be provided below.

[0043] In the side view, the separation trench 102A is formed to extend between a first surface 101A on the Z-arrow direction side of the substrate 101 and a second surface 101B opposite to the first surface 101A on the opposite side. In other words, the separation trench 102A is configured to extend through the thickness direction of the substrate 101. Here, the separation trench 102A extends with a constant width dimension in both the Z-arrow and Y-arrow directions. Therefore, although not shown in the figure, when viewed from the Z-arrow direction (hereinafter referred to as "in the plan view"), the insulating separator 102 has a lattice-like planar shape. Additionally, the pixel 10, surrounded by the grid-shaped insulating separator 102, has a rectangular planar shape, specifically a square planar shape.

[0044] The insert 102B is embedded inside the separation trench 102A. In the first embodiment, the insert 102B is formed of an insulator such as silicon dioxide (SiO2).

[0045] It is important to note that the planar shape of pixel 10 is not necessarily limited to a rectangular shape, and the planar shape of insulating separator 102 is not limited to a grid shape. For example, pixel 10 can have a rectangular planar shape, a polygonal planar shape (including pentagonal and higher-order polygonal shapes), a circular planar shape, or an elliptical planar shape. When the planar shape of pixel 10 changes, the planar shape of insulating separator 102 will also change to adapt to the change in the shape of pixel 10.

[0046] (3) The composition of pixel 10 In the region surrounded by the insulating separator 102, the pixel 10 is disposed in an n-type semiconductor region (n-type well region) 103 formed within the substrate 101. The n-type semiconductor region 103 is formed to have a low impurity density. As described above, pixel 10 includes an avalanche photodiode (SPAD) 11. The SPAD 11 is disposed inside an insulating separator 102, and a p-type semiconductor region 106 is inserted between the SPAD 11 and the insulating separator 102. The p-type semiconductor region 106 is formed along the inner wall of the insulating separator 102. The p-type semiconductor region 106 serves as a pinning region to suppress the generation of dark current. The p-type semiconductor region 106 also serves as part of the anode power line VLsp.

[0047] The avalanche photodiode 11 includes an anode region 104 and a cathode region 105. The anode region 104 is disposed on the second surface 101B side of the substrate 101. The anode region 104 is formed of a p-type semiconductor region with an impurity density higher than that of the p-type semiconductor region 106. Furthermore, in the planar view, the anode region 104 is formed on the inner side of the inner wall of the insulating separator 102, and the p-type semiconductor region 106 is inserted between the anode region 104 and the insulating separator 102. Therefore, the anode region 104 has a rectangular planar shape similar to the planar shape of the pixel 10.

[0048] Anode region 104 is supplied with an anode voltage Vsp through p-type semiconductor region 106 (see [link]). Figure 1 In other words, the anode voltage Vsp is supplied from the outer periphery of pixel 10 to the anode region 104.

[0049] A cathode region 105 is disposed between an anode region 104 and a second surface 101B of the substrate 101. The cathode region 105 is formed of an n-type semiconductor region with an impurity density higher than that of the n-type semiconductor region 103. The cathode region 105 is connected to the anode region 104 via a pn bond. Furthermore, in the planar view, the cathode region 105 is formed on the inner side of the inner wall of the insulating separator 102, and the n-type semiconductor region 103 of the substrate 101 is inserted between the cathode region 105 and the insulating separator 102. Therefore, the cathode region 105 has a rectangular planar shape similar to that of the anode region 104, and the planar shape of the cathode region 105 is similar to that of the anode region 104, but the planar shape of the cathode region 105 is slightly smaller than that of the anode region 104.

[0050] (4) Composition of optical filter 108 and optical lens 109 Pixel 10 includes an optical filter 108 and an optical lens 109 that are sequentially stacked on the first surface 101A of substrate 101. In the side view, the optical filter 108 is embedded in the uneven cross-sectional portion of the n-type semiconductor region 103 formed on the first surface 101A. That is, the optical filter 108 has an uneven cross-section on the first surface 101A side. Additionally, the optical filter 108 has a flat surface on the optical lens 109 side. The optical filter 108 scatters light incident through the optical lens 109 and causes the scattered light to be received by the avalanche photodiode 11.

[0051] On the other hand, in the side view, the optical lens 109 has a surface on the Z-arrow direction side, and this surface is curved toward the Z-arrow direction for each pixel 10 or for multiple pixels 10. That is, the optical lens 109 converges the incident light. The light converged by the optical lens 109 is received by the avalanche photodiode 11. For example, the optical lens 109 is formed of a transparent resin material. Here, the optical lens 109 is formed as an on-plate lens.

[0052] (5) Composition of wiring layer 111 like Figure 2 As shown, a wiring layer 111 is provided on the second surface 101B of the substrate 101. The wiring layer 111 includes contact hole wiring 112, wiring 113, wiring 114 and insulator 115. Wiring layer 111 is configured to electrically connect protection circuit 2 to avalanche photodiode 11 of photodetector 1, to readout circuit 3, or to other components. In other words, wiring layer 111 is configured to electrically connect photodetector 1 to circuitry 5.

[0053] Wiring 113 is located at the position closest to the second surface 101B of the substrate 101. For example, wiring 113 is formed of a gate electrode material such as polysilicon. Specifically, wiring 113 is formed of polysilicon (semiconductor) with added n-type impurities to adjust the resistance value. Wiring 113 constitutes the resistive element R of the first protection circuit 21. Details of the resistive element R will be described later.

[0054] On the side opposite to the direction of arrow Z, wiring 114 is disposed on the second surface 101B of substrate 101, passing over wiring 113. In the first embodiment, wiring 114 is formed of multiple layers. For example, wiring 114 is formed of wiring materials with excellent conductivity, such as copper (Cu) or aluminum (Al)-Cu. In pixel 10, wiring 114 is electrically connected to p-type semiconductor region 106 and forms an anode power line VLsp that provides anode voltage Vsp to anode region 104 of avalanche photodiode 11. Wiring 114 also constitutes a wiring that electrically connects the cathode region 105 of the avalanche photodiode 11 to the resistive element R of the first protection circuit 21.

[0055] Here, wiring 114 also forms one and the other electrodes of capacitor element C in the first protection circuit 21. Details of capacitor element C will be described later.

[0056] Contact hole wiring 112 electrically connects avalanche photodiode 11 to wiring 114, electrically connects p-type semiconductor region 106 to wiring 114, and electrically connects wiring 113 to wiring 114, etc. For example, contact hole wiring 112 is formed of wiring material or metal material such as W.

[0057] In fact, insulator 115 is formed of multiple layers of insulating film. For example, insulator 115 is configured to electrically isolate wiring 113, etc., from wiring 114, etc., to protect them. Insulator 115 also serves as the dielectric of capacitor element C. For example, insulator 115 is formed of insulating materials such as silicon dioxide (SiO2).

[0058] (6) Composition of the first protection circuit 21 and the resistor element R Figure 3 An example of the planar configuration of the first protection circuit 21 provided in the protection circuit 2 of the light detection device 1 is shown. As mentioned above and as Figure 2 As shown, the resistive element R of the first protection circuit 21 is composed of wiring 113 of wiring layer 111. That is, the polysilicon (semiconductor) that serves as the resistive element R is indirectly connected to the cathode region of the avalanche photodiode 11 via contact hole wiring (metal) 112, which is inserted between the polysilicon and the cathode region of the avalanche photodiode 11.

[0059] like Figure 3 As shown, the resistive element R extends towards the X-arrow direction while alternately meandering in the Y-arrow direction and in the opposite direction. In other words, the resistive element R has a curved and folded shape in the planar view. Therefore, it is possible to set a large resistance value for the resistive element R while occupying a small area.

[0060] (7) The structure of the capacitor element C in the first protection circuit 21 like Figure 2 and Figure 3 As shown, capacitor C and resistor R are electrically connected in parallel. Details will be explained below. The capacitor element C includes a first conductor 1141 serving as one electrode, an insulator 115 serving as a dielectric, and a second conductor 1142 serving as the other electrode.

[0061] The first electrical conductor 1141 is disposed in the same wiring layer as the wiring 114 near the resistive element R, and is formed of the same wiring material as the wiring 114. The first electrical conductor 1141 is electrically connected in parallel to the middle portion of the resistive element R in the resistance length direction through the contact hole wiring 112. In the first embodiment, the first electrical conductor 1141 is connected to the middle position of the resistive element in the resistance length direction. Here, the resistance length of the resistor element R refers to the length from one end of the resistor element R to the other end. Furthermore, the direction of resistance length refers to the direction in which the resistance length of the resistor element R increases.

[0062] The first electrical conductor 1141 is configured to overlap with the resistive element R. In other words, the first electrical conductor 1141 is located in the region where the resistive element R is located. The first electrical conductor 1141 includes a long segment extending in the Y-direction from the location where it is connected to the resistive element R, and a long segment extending in the X-direction that intersects the middle portion of the long segment extending in the Y-direction in the direction of extension. That is, the first electrical conductor 1141 has a cross shape in the plan view. The width of the long segment of the first electrical conductor 1141 is not particularly limited, but is set within the range of the bending and folding distance of the resistive element R.

[0063] The second conductor 1142 is disposed in the same wiring layer as wiring 114. The first conductor 1141 and the insulator 115 are inserted between the second conductor 1142 and the resistive element R, and the second conductor 1142 is formed of the same wiring material as wiring 114. Although not shown, according to the first embodiment, the second conductor 1142 is configured to overlap with the first conductor 1141 and has a planar shape similar to that of the first conductor 1141. Of course, the planar shape of the second conductor 1142 can also be different from that of the first conductor 1141, as long as the second conductor 1142 is also configured to overlap with the first conductor 1141. In summary, the capacitor element C is composed of the first conductor 1141, the insulator 115, and the second conductor 1142.

[0064] (8) Composition of circuit device 5 Back Figure 2 The circuit device 5 is configured using a substrate 501 as a base structure. The substrate 501 is disposed on the second surface 101B side of the substrate 101. In other words, in a side view, the light detection device 1 is stacked on the Z-arrow direction side of the circuit device 5. For example, in the first embodiment, the substrate 501 is formed from a monocrystalline silicon substrate in a manner similar to that of the substrate 101. Here, substrate 501 corresponds to the "second substrate" according to the present technology.

[0065] The substrate 501 is provided with various components constituting the protection circuit 2, including the second protection circuit 22, the readout circuit 3, and the time measurement circuit 4 (see...). Figure 1 The detailed composition and description of components, etc., will be omitted.

[0066] (9) Composition of wiring layer 511 like Figure 2 As shown, a wiring layer 511 is provided on the second surface 101B side of the substrate 501. Although detailed structure and description are omitted, similar to the wiring layer 111, the wiring layer 511 also includes contact hole wiring, wiring, insulator, etc. Wiring layer 111 and wiring layer 511 are electrically and mechanically connected to each other via terminals (not shown) inserted between wiring layer 111 and wiring layer 511. For example, this connection is a copper-copper connection.

[0067] [Effects] As mentioned above and as Figures 1 to 3 As shown, the light detection device 1 according to the first embodiment includes an avalanche photodiode 11, a protection circuit 2, and a first electrical conductor 1141. In the avalanche photodiode 11, an anode voltage (first fixed voltage) Vsp is applied to the anode region to multiply the charge carriers generated by the incident photons. The protection circuit 2 includes a first protection circuit 21. The first protection circuit 21 includes a resistive element R electrically connected in series with the cathode region of the avalanche photodiode 11 to protect the readout circuit 3 from overcurrent. A first conductor 1141 is electrically connected in parallel with the resistive element R. When photons with a light intensity greater than expected are incident on the avalanche photodiode 11, the photodetector 1 with this configuration can significantly reduce the internal impedance of the avalanche photodiode 11 and absorb and reduce the overcurrent flowing through the resistive element R. This can protect the resistive element R and increase its tolerance. As a result, the first protection circuit 21 can be protected, and the tolerance of the photodetector 1 to overcurrent can be increased.

[0068] In addition, such as Figures 1 to 3 As shown, in the optical detection device 1, the first electrical conductor 1141 is positioned opposite the second electrical conductor 1142 via an insulator 115, and the second electrical conductor 1142 is electrically connected to a fixed voltage (second fixed voltage) Vc. The first electrical conductor 1141, the insulator 115, and the second electrical conductor 1142 constitute a capacitor element C, which is used to protect the resistive element R from overcurrent. The photodetector 1 with this configuration enables the capacitive element C to absorb and reduce the overcurrent flowing through the resistive element R of the first protection circuit 21. This protects the resistive element R and increases its tolerance. Consequently, the first protection circuit 21 is protected, and the photodetector 1's tolerance to overcurrent is increased.

[0069] In addition, such as Figure 3 As shown, in the optical detection device 1, when viewed from the thickness direction of the resistive element R (in the plan view), the first electrical conductor 1141 is configured to overlap with the resistive element R. The optical detection device 1 with this configuration can place the first electrical conductor 1141, i.e., the capacitor element C, within the area occupied by the resistive element R, thereby improving the area utilization rate.

[0070] In addition, such as Figure 2 and Figure 3 As shown, in the optical detection device 1, the first electrical conductor 1141 is electrically connected in parallel with the middle portion of the resistive element R in the direction of resistance length. The optical detection device 1 with this configuration is able to absorb and reduce the overcurrent flowing through the resistive element R in the optimal region, thereby increasing the tolerance of the resistive element R of the first protection circuit 21 in the optimal region.

[0071] In addition, such as Figures 1 to 3 As shown, the ranging system 6 includes a light detection device 1 and a circuit device 5. The photodetector 1 includes an avalanche photodiode 11, a protection circuit 2, and a first electrical conductor 1141. In the avalanche photodiode 11, an anode voltage Vsp is applied to the anode region to multiply the charge carriers generated by the incident photons. The protection circuit 2 includes a first protection circuit 21. The first protection circuit 21, including a resistive element R, is electrically connected in series with the cathode region of the avalanche photodiode 11 to protect the readout circuit 3 from overcurrent. The first electrical conductor 1141 is electrically connected in parallel with the resistive element R. On the other hand, the circuit device 5 includes an internal circuit and a time measurement circuit 4. The internal circuit constitutes a readout circuit 3. The readout circuit 3 is electrically connected to the avalanche photodiode 11 via the protection circuit 2 and reads out the multiplied charge carriers. The time measurement circuit 4 is electrically connected to the output of the readout circuit 3 and measures the time of flight of light. As described above, the ranging system 6 with this configuration can improve the tolerance of the optical detection device 1 to overcurrent.

[0072] <2. Second Embodiment> Reference Figure 4The optical detection device 1 and the ranging system 6 according to the second embodiment of this disclosure will be described. In the second embodiment, an example in which the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the first embodiment is changed will be described. It should be noted that in the second embodiment and subsequent embodiments, components that are the same or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the first embodiment are indicated by the same reference numerals, and redundant descriptions will be omitted.

[0073] [The configuration of the optical detection device 1 and the ranging system 6] Figure 4 An example of a planar configuration of the resistive element R and the capacitive element C of the protection circuit 2 provided in the light detection device 1 according to the second embodiment is shown.

[0074] like Figure 4 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the first embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2. A plurality of first electrical conductors 1141 serve as electrodes of the capacitor element C and are arranged along the resistance length direction of the resistor element R. Specifically, the plurality of first electrical conductors 1141 are arranged to be electrically connected in parallel at constant intervals from one end of the resistor element R to the other along the resistance length direction. There is no limitation on the number of first electrical conductors 1141. Here, the number of first electrical conductors 1141 is three. In the second embodiment, one end of each of the plurality of first electrical conductors 1141 is connected to the resistive element R at an edge opposite to the direction of the Y-arrow. The other end of each of the plurality of first electrical conductors 1141 extends in the bending direction, i.e., in the direction of the Y-arrow.

[0075] Next, the second conductor 1142 ( Figure 4 Not shown in the image, see [link / reference]. Figure 2 The second conductor 1142 is configured to overlap with the first conductor 1141, and the insulator 115 is inserted between the second conductor 1142 and the first conductor 1141, thereby forming a capacitor element C. It is also possible to provide multiple second conductors 1142 for each first conductor 1141, or to provide a single second conductor 1142 for multiple first conductors 1141.

[0076] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the first embodiment, and redundant descriptions will be omitted.

[0077] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the second embodiment can achieve similar effects to those achieved by the optical detection device 1 and the ranging system 6 according to the first embodiment.

[0078] In addition, such as Figure 4 As shown, in the optical detection device 1, a plurality of first electrical conductors 1141 are arranged along the resistance length direction of the resistive element R in the first protection circuit 21. The photodetector 1 with this configuration can gradually absorb the overcurrent flowing through the resistive element R along the length of the resistor, thereby gradually reducing the overcurrent. This protects the resistive element R and increases its tolerance. As a result, the first protection circuit 21 is protected, and the photodetector 1's tolerance to overcurrent is increased.

[0079] <3. Third Embodiment> Reference Figure 5 The optical detection device 1 and the ranging system 6 according to the third embodiment of this disclosure will be described. In the third embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the second embodiment will be described.

[0080] [The configuration of the optical detection device 1 and the ranging system 6] Figure 5 An example of a planar configuration of the resistive element R and the capacitive element C of the protection circuit 2 provided in the light detection device 1 according to the third embodiment is shown.

[0081] like Figure 5 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the second embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0082] The resistive element R is divided into multiple segmented resistive elements along its length. Details will be provided. The number of segments is not limited, but the resistive element R comprises five segmented resistive elements R1 to R5, which have equal resistive lengths and extend in the Y-direction. In the plan view, the segmented resistive elements R1 to R5 are arranged in parallel and sequentially in the X-direction.

[0083] On the other hand, the plurality of first electrical conductors 1141 are arranged in a manner similar to that of the first electrical conductor 1141 of the photodetector 1 according to the second embodiment. Furthermore, the first electrical conductors 1141 electrically connect a plurality of segmented resistive elements R1 to R5 in series. The details will be explained below. One end of the segmented resistive element R1 is electrically connected to the avalanche photodiode 11. The other end of the segmented resistive element R1 is connected to one end of the segmented resistive element R2 via a first electrical conductor 1141, which is inserted between the other end of the resistive element R1 and one end of the resistive element R2. Similarly, the other end of the segmented resistor R2 is connected to one end of the segmented resistor R3 via a first conductor 1141, which is inserted between the other end of resistor R2 and one end of resistor R3. The other end of the segmented resistor R3 is connected to one end of the segmented resistor R4 via the first conductor 1141, which is inserted between the other end of resistor R3 and one end of resistor R4. The other end of the segmented resistor R4 is connected to one end of the segmented resistor R5 via the first conductor 1141, which is inserted between the other end of resistor R4 and one end of resistor R5. Additionally, the other end of the segmented resistor R5 is connected to the second protection circuit 22.

[0084] The first conductor 1141 connecting the individual segmented resistive elements R1 to R5 extends in the direction of the Y arrow or in the opposite direction of the Y arrow along the bending and folding direction.

[0085] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the first embodiment, and redundant descriptions will be omitted.

[0086] [Effects] As described above, the light detection device 1 and the ranging system 6 according to the third embodiment can achieve similar effects to those achieved by the light detection device 1 and the ranging system 6 according to the second embodiment.

[0087] <4. Fourth Embodiment> Reference Figure 6 The optical detection device 1 and the ranging system 6 according to the fourth embodiment of this disclosure will be described. In the fourth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the second embodiment will be described.

[0088] [The configuration of the optical detection device 1 and the ranging system 6] Figure 6 An example of a planar configuration of the resistive element R and the capacitive element C of the protection circuit 2 provided in the optical detection device 1 according to the fourth embodiment is shown.

[0089] like Figure 6As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the second embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0090] In a manner similar to the first electrical conductor 1141 of the photodetector 1 according to the second embodiment described above, a plurality of first electrical conductors 1141 are used as one electrode of the capacitor element C and are arranged along the resistance length direction of the resistor element R. The details will be explained below. Here, the number of first electrical conductors 1141 is six. In addition, each of the first electrical conductors 1141 is electrically connected in parallel with the resistive element R at the middle position in the direction of extension, that is, in the direction of the Y arrow.

[0091] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the second embodiment, and redundant descriptions will be omitted.

[0092] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the fourth embodiment can achieve similar effects to those achieved by the optical detection device 1 and the ranging system 6 according to the second embodiment.

[0093] <5. Fifth Embodiment> Reference Figure 7 The optical detection device 1 and the ranging system 6 according to the fifth embodiment of this disclosure will be described. In the fifth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the fourth embodiment will be described.

[0094] [The configuration of the optical detection device 1 and the ranging system 6] Figure 7 An example of the planar configuration of the resistive element R and the capacitive element C of the protection circuit 2 provided in the optical detection device 1 according to the fifth embodiment is shown.

[0095] like Figure 7 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the fourth embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0096] In the fifth embodiment, capacitor element C includes capacitor element C1 and capacitor element C2 electrically connected in series with capacitor element C1. Details will be provided below. Capacitor element C1 includes a first conductor 1141, an insulator 115, and a second conductor 1142. On the other hand, capacitor element C2 includes a second conductor 1142, an insulator 115, and a third conductor 1143, which serves as another electrode, and is further divided into a second conductor 1142, an insulator 115, and a third conductor 1143, which is formed by wiring 114, which is stacked on the side of the second conductor 1142 opposite to the first conductor 1141, separated by the insulator 115. In other words, the capacitor element C is composed of multiple layers of electrical conductors, including a first electrical conductor 1141, a second electrical conductor 1142, and a third electrical conductor 1143.

[0097] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the fourth embodiment, and redundant descriptions will be omitted.

[0098] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the fifth embodiment can achieve similar effects to those achieved by the optical detection device 1 and the ranging system 6 according to the second embodiment.

[0099] <6. Sixth Embodiment> Reference Figure 8 The optical detection device 1 and the ranging system 6 according to the sixth embodiment of this disclosure will be described. In the sixth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the third embodiment will be described.

[0100] [The configuration of the optical detection device 1 and the ranging system 6] Figure 8 An example is shown of the resistive element R and the capacitive element C of the protection circuit 2 provided in the light detection device 1 according to the sixth embodiment, as well as the planar configuration of the pixel 10.

[0101] like Figure 8 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the first and third embodiments, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0102] In the plan view, the resistive element R is positioned to overlap with pixel 10. Details will be explained below. The resistive element R is positioned inside the insulating separator 102 surrounding pixel 10 to overlap with the avalanche photodiode 11. Here, the resistive element R comprises four segmented resistive elements R1 to R4 extending along the outer periphery of pixel 10.

[0103] The segmented resistor elements R1 and R3 are opposite each other in the X-arrow direction and extend in the Y-arrow direction. The segmented resistor elements R2 and R4 are opposite each other in the Y-arrow direction and extend in the X-arrow direction.

[0104] One end of the segmented resistor element R1 is electrically connected to the avalanche photodiode 11 via wiring 114. The other end of the segmented resistor element R1 is connected to one end of the segmented resistor element R2 via a first conductor 1141, which is inserted between resistor element R1 and resistor element R2. Similarly, the other end of the segmented resistor R2 is connected to one end of the segmented resistor R3 via a first conductor 1141, which is inserted between resistor R2 and resistor R3. The other end of the segmented resistor R3 is connected to one end of the segmented resistor R4 via the first conductor 1141, which is inserted between resistor R3 and resistor R4. The other end of the segmented resistor R4 is connected to the second protection circuit 22.

[0105] The first conductor 1141, which connects the segmented resistive elements R1 to R4, forms the capacitor element C.

[0106] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the third embodiment, and redundant descriptions will be omitted.

[0107] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the sixth embodiment can achieve similar effects to those achieved by the optical detection device 1 and the ranging system 6 according to the third embodiment.

[0108] In addition, such as Figure 8 As shown, in the light detection device 1, in the plan view, the resistive element R and the capacitive element C are arranged to overlap with the pixel 10. The light detection device 1 with this configuration can set the resistive element R and the capacitive element C within the area occupied by the pixel 10, thereby improving the area utilization rate.

[0109] <7. Seventh Embodiment> Reference Figure 9 The light detection device 1 and the ranging system 6 according to the seventh embodiment of this disclosure will be described. In the seventh embodiment, an example of combining the light detection device 1 and the ranging system 6 according to the fourth embodiment with the light detection device 1 and the ranging system 6 according to the sixth embodiment will be described.

[0110] [The configuration of the optical detection device 1 and the ranging system 6] Figure 9 An example of the resistive element R and the capacitive element C of the protection circuit 2 provided in the light detection device 1 according to the seventh embodiment and the planar configuration of the pixel 10 are shown.

[0111] like Figure 9 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the sixth embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0112] In the plan view, the resistive element R is positioned to overlap with pixel 10. The resistive element R is positioned inside the insulating separator 102 surrounding pixel 10 to overlap with the avalanche photodiode 11. Here, the resistive element R extends along the outer periphery of pixel 10. One end of the resistor R is electrically connected to the avalanche photodiode 11 via wiring 114. The other end of the resistor R is connected to the second protection circuit 22.

[0113] Similar to the first electrical conductor 1141 according to the fourth embodiment, a plurality of first electrical conductors 1141 serve as one electrode of the capacitor element C and are arranged along the resistance length direction of the resistor element R. Each first electrical conductor 1141 extends toward the center side of the pixel 10, thereby increasing the capacitor area. As described above, the first electrical conductor 1141 includes an insulator 115 and a second electrical conductor 1142 ( Figure 9 Not shown in the image, see [link / reference]. Figure 2 ), thus forming capacitor element C.

[0114] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the fourth and sixth embodiments, and redundant descriptions will be omitted.

[0115] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the seventh embodiment can achieve a combination of the effects achieved by the optical detection device 1 and the ranging system 6 according to the fourth embodiment and the effects achieved by the optical detection device 1 and the ranging system 6 according to the sixth embodiment.

[0116] <8. Eighth Embodiment> Reference Figure 10 and Figure 11 The optical detection device 1 and the ranging system 6 according to the eighth embodiment of this disclosure will be described. In the eighth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the sixth embodiment will be described.

[0117] [The configuration of the optical detection device 1 and the ranging system 6] Figure 10 An example is shown of the resistive element R and the capacitive element C of the protection circuit 2 provided in the light detection device 1 according to the eighth embodiment, and the vertical cross-section of the pixel 10. Figure 11 An example of the resistive element R and the capacitive element C of the protection circuit 2 and the planar configuration of the pixel 10 is shown.

[0118] like Figure 10 and Figure 11 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the sixth embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0119] In the planar view, the resistive element R includes four segmented resistive elements R1 to R4 extending along the outer periphery of pixel 10. Here, for example, as described above, the segmented resistive element R1 is formed of polysilicon, one end of which is directly electrically connected to the cathode region of avalanche photodiode 11.

[0120] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the sixth embodiment, and redundant descriptions will be omitted.

[0121] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the eighth embodiment can achieve similar effects to those achieved by the optical detection device 1 and the ranging system 6 according to the sixth embodiment.

[0122] <9. Ninth Embodiment> Reference Figure 12 and Figure 13 The light detection device 1 and the ranging system 6 according to the ninth embodiment of this disclosure will be described. In the ninth embodiment, an example of combining the light detection device 1 and the ranging system 6 according to the fifth embodiment with the light detection device 1 and the ranging system 6 according to the seventh embodiment will be described.

[0123] [The configuration of the optical detection device 1 and the ranging system 6] Figure 12 An example is shown of the resistive element R and the capacitive element C of the protection circuit 2 provided in the light detection device 1 according to the ninth embodiment, and the vertical cross-section of the pixel 10. Figure 13 An example of the resistive element R and the capacitive element C of the protection circuit 2 and the planar configuration of the pixel 10 is shown.

[0124] like Figure 12 and Figure 13 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the seventh embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0125] Furthermore, similar to the capacitor element C according to the fifth embodiment described above, the capacitor element C includes a capacitor element C1 and a capacitor element C2 electrically connected in series with the capacitor element C1. That is, the capacitor element C is composed of a multilayer of electrical conductors, on which a first electrical conductor 1141, a second electrical conductor 1142, and a third electrical conductor 1143 are stacked.

[0126] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the fifth and seventh embodiments, and redundant descriptions will be omitted.

[0127] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the ninth embodiment can achieve a combination of the effects achieved by the optical detection device 1 and the ranging system 6 according to the fifth embodiment and the effects achieved by the optical detection device 1 and the ranging system 6 according to the seventh embodiment.

[0128] <10. Tenth Embodiment> Reference Figure 14 The optical detection device 1 and the ranging system 6 according to the tenth embodiment of this disclosure will be described. In the tenth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the first embodiment will be described.

[0129] [The configuration of the optical detection device 1 and the ranging system 6] Figure 14 An example is shown of the resistive element R and the capacitive element C of the protection circuit 2 provided in the light detection device 1 according to the tenth embodiment, and the vertical cross-section of the pixel 10.

[0130] like Figure 14 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the sixth embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0131] As described above, the resistive element R is formed by wiring 113. Here, a metal (metal resistive material) is used as wiring 113. TaO can be practically used as this metal. x TaSiO x wait.

[0132] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the first embodiment, and redundant descriptions will be omitted.

[0133] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the tenth embodiment can achieve similar effects to those achieved by the optical detection device 1 and the ranging system 6 according to the first embodiment.

[0134] <11. Eleventh Embodiment> Reference Figure 15 and Figure 16 The eleventh embodiment of the light detection device 1 and the ranging system 6 according to this disclosure will be described. In the eleventh embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the light detection device 1 and the ranging system 6 according to the first embodiment will be described.

[0135] [The configuration of the optical detection device 1 and the ranging system 6] Figure 15 An example of the circuit configuration of a portion of the optical detection device 1 and the ranging system 6 according to the eleventh embodiment is shown. Figure 16 An example is shown, consisting of a resistive element R and a capacitive element C of the protection circuit 2 provided in the light detection device 1, and a vertical cross-section of the pixel 10.

[0136] like Figure 15 and Figure 16 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the first embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0137] In the eleventh embodiment, the resistive element R is composed of a transistor resistive element. Here, for example, a p-type IGFET is used as the transistor resistive element. The p-type IGFET includes a gate insulating gate 118 disposed in the n-type well region 116, a wiring 113 serving as the gate electrode, and a pair of p-type semiconductor regions 117 serving as the source region and the drain region. It should be noted that, for example, n-type IGFETs can also be used as transistor resistors.

[0138] On the other hand, the capacitor element C includes capacitors C3 and C4. Capacitor C3 is generated between the wiring (gate electrode) 113 and one of the p-type semiconductor regions 117. Capacitor C4 is generated between the wiring (gate electrode) 113 and the other p-type semiconductor region 117.

[0139] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the first embodiment, and redundant descriptions will be omitted.

[0140] [Effects] As described above, the light detection device 1 and the ranging system 6 according to the eleventh embodiment can achieve similar effects to those achieved by the light detection device 1 and the ranging system 6 according to the first embodiment.

[0141] <12. Twelfth Embodiment> Reference Figure 17 The optical detection device 1 and the ranging system 6 according to the twelfth embodiment of this disclosure will be described. In the twelfth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the first embodiment will be described.

[0142] [The configuration of the optical detection device 1 and the ranging system 6] Figure 17 An example of the circuit configuration of a portion of the optical detection device 1 and the ranging system 6 according to the twelfth embodiment is shown.

[0143] like Figure 17 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the first embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0144] In the twelfth embodiment, a pixel 10 including an avalanche photodiode 11 is disposed in a substrate (first substrate) 101. A first protection circuit 21 of the protection circuit 2 is disposed in a substrate (second substrate) 501. As described above, the first protection circuit 21 includes a resistive element R and a capacitive element C. Here, the light detection device 1 according to the twelfth embodiment is composed of a substrate 101 including pixels 10 and a portion of the substrate 501 corresponding to the first protection circuit 21. It should be noted that the ranging system 6 includes the first protection circuit 21.

[0145] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the first embodiment, and redundant descriptions will be omitted.

[0146] [Effects] As described above, the light detection device 1 and the ranging system 6 according to the twelfth embodiment can achieve similar effects to those achieved by the light detection device 1 and the ranging system 6 according to the first embodiment.

[0147] <13. Thirteenth Embodiment> Reference Figure 18 The optical detection device 1 and the ranging system 6 according to the thirteenth embodiment of this disclosure will be described. In the thirteenth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the first embodiment will be described.

[0148] [The configuration of the optical detection device 1 and the ranging system 6] Figure 18 An example of the circuit configuration of a portion of the optical detection device 1 and the ranging system 6 according to the thirteenth embodiment is shown.

[0149] like Figure 18 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the first embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0150] In the thirteenth embodiment, the first protection circuit 21 of the protection circuit 2 is configured to span across the substrate (first substrate) 101 and the substrate (second substrate) 501. Details thereof will be explained below. The resistor element R in the first protection circuit 21 is divided into a divided resistor element R1 and a divided resistor element R2. The divided resistor element R1 is disposed in the base 101. The divided resistor element R2 is disposed in the base 501 and is electrically connected in series with the divided resistor element R1.

[0151] Additionally, capacitor C is electrically connected in parallel with the segmented resistor R1. Note that capacitor C can also be electrically connected in parallel with the segmented resistor R2, or in parallel with both the segmented resistor R1 and the segmented resistor R2.

[0152] Here, in a manner similar to the optical detection device 1 according to the twelfth embodiment described above, the optical detection device 1 according to the thirteenth embodiment is composed of a substrate 101 and a portion of the substrate 501 including the first protection circuit 21.

[0153] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the first embodiment, and redundant descriptions will be omitted.

[0154] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the thirteenth embodiment can achieve similar effects to those achieved by the optical detection device 1 and the ranging system 6 according to the first embodiment.

[0155] <14. Fourteenth Embodiment> Reference Figure 19 The light detection device 1 and the ranging system 6 according to the fourteenth embodiment of this disclosure will be described. In the fourteenth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the light detection device 1 and the ranging system 6 according to the first embodiment will be described.

[0156] [The configuration of the optical detection device 1 and the ranging system 6] Figure 19 An example of the circuit configuration of a portion of the optical detection device 1 and the ranging system 6 according to the fourteenth embodiment is shown.

[0157] like Figure 19 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the first embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0158] In the fourteenth embodiment, the resistive element R of the protection circuit 2 is electrically connected to the cathode region of the avalanche photodiode 11 in a manner similar to that of the avalanche photodiode 1 in the photodetector 1 according to the first embodiment. Here, the cathode region is an n-type semiconductor region. On the other hand, the resistive element R is formed of polycrystalline silicon with p-type impurities added. That is, the cathode region and the resistive element R have different polarities.

[0159] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the first embodiment, and redundant descriptions will be omitted.

[0160] [Effects] As described above, the light detection device 1 and the ranging system 6 according to the fourteenth embodiment can achieve similar effects to those achieved by the light detection device 1 and the ranging system 6 according to the first embodiment.

[0161] <15. Fifteenth Embodiment> Reference Figure 20 The optical detection device 1 and the ranging system 6 according to the fifteenth embodiment of this disclosure will be described. In the fifteenth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the optical detection device 1 and the ranging system 6 according to the first embodiment will be described.

[0162] [The configuration of the optical detection device 1 and the ranging system 6] Figure 20 An example of the circuit configuration of a portion of the optical detection device 1 and the ranging system 6 according to the fifteenth embodiment is shown.

[0163] like Figure 20 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the first embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0164] In the fifteenth embodiment, the resistive element R of the protection circuit 2 is electrically connected to the anode region of the avalanche photodiode 11 in a manner different from that of the avalanche photodiode 11 in the photodetector 1 according to the first embodiment. Here, the anode region is a p-type semiconductor region.

[0165] The cathode region is supplied with a cathode voltage Vsp by the cathode power line VLsp. The cathode voltage Vsp is a large positive voltage that causes avalanche multiplication, i.e., exceeding a predetermined breakdown voltage (first fixed voltage). For example, the cathode voltage is a voltage exceeding 20 V.

[0166] On the other hand, the resistive element R is formed from polycrystalline silicon with added n-type impurities. That is, the anode region and the resistive element R have different polarities.

[0167] In addition, the first clamping element Tc1 of the second protection circuit 22 is implemented by an n-type IGFET.

[0168] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the first embodiment, and redundant descriptions will be omitted.

[0169] [Effects] As described above, the optical detection device 1 and the ranging system 6 according to the fifteenth embodiment can achieve similar effects to those achieved by the optical detection device 1 and the ranging system 6 according to the first embodiment. <16. Sixteenth Embodiment> Reference Figure 21 The light detection device 1 and the ranging system 6 according to the sixteenth embodiment of this disclosure will be described. In the sixteenth embodiment, an example of changing the configuration of the resistive element R and the capacitive element C of the protection circuit 2 in the light detection device 1 and the ranging system 6 according to the fifteenth embodiment will be described.

[0170] [The configuration of the optical detection device 1 and the ranging system 6] Figure 21 An example of the circuit configuration of a portion of the optical detection device 1 and the ranging system 6 according to the sixteenth embodiment is shown.

[0171] like Figure 21 As shown, in a manner similar to the optical detection device 1 and the ranging system 6 according to the fifteenth embodiment, the optical detection device 1 includes a resistive element R and a capacitive element C in the first protection circuit 21 of the protection circuit 2.

[0172] In the sixteenth embodiment, the resistive element R of the protection circuit 2 is electrically connected to the anode region of the avalanche photodiode 11 in a manner similar to that of the avalanche photodiode 1 in the photodetector 1 according to the fifteenth embodiment. Here, the anode region is a p-type semiconductor region.

[0173] On the other hand, the resistive element R is formed from polycrystalline silicon with p-type impurities added. That is, the anode region and the resistive element R have the same polarity.

[0174] In addition, the first clamping element Tc1 of the second protection circuit 22 is implemented by an n-type IGFET.

[0175] The components other than those described above are the same as or substantially the same as those of the optical detection device 1 and the ranging system 6 according to the fifteenth embodiment, and redundant descriptions will be omitted.

[0176] [Effects] As described above, the light detection device 1 and the ranging system 6 according to the sixteenth embodiment can achieve similar effects to those achieved by the light detection device 1 and the ranging system 6 according to the fifteenth embodiment.

[0177] <17. Examples of Applications of Moving Bodies> The technology disclosed herein (the Technology) is applicable to a variety of products. For example, the Technology disclosed herein can be implemented as a device mounted on various mobile bodies such as automobiles, electric vehicles, hybrid vehicles, autonomous two-wheelers, bicycles, personal motor vehicles, airplanes, unmanned aerial vehicles, ships, or robots.

[0178] Figure 22 This is a block diagram illustrating an example of a schematic configuration of a vehicle control system, which serves as an example of a mobile body control system to which the technology according to embodiments of this disclosure is applicable.

[0179] The vehicle control system 12000 includes multiple electronic control units interconnected via a communication network 12001. Figure 22 In the example shown, 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 a comprehensive control unit 12050. Furthermore, as functional components of the comprehensive control unit 12050, a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown.

[0180] The drive system control unit 12010 controls the operation of equipment 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 various devices such as: drive force generating devices for generating vehicle driving force, such as internal combustion engines and drive motors; drive force transmission mechanisms for transmitting driving force to the wheels; steering mechanisms for adjusting the vehicle's steering angle; and braking devices for generating vehicle braking force.

[0181] The vehicle body system control unit 12020 controls the operation of various devices installed on the vehicle body according to various programs. For example, the vehicle body system control unit 12020 functions as a control device for various devices such as: keyless entry system; smart key system; power windows; or various lights such as headlights, reversing lights, brake lights, turn signals, fog lights, etc. In this case, radio waves or signals from a portable device that replaces the key can be input to the vehicle body system control unit 12020. The vehicle body system control unit 12020 receives these input radio waves or signals and controls the vehicle's door locks, power windows, lights, etc.

[0182] The exterior information detection unit 12030 detects information related to the exterior of the vehicle, including information from the vehicle control system 12000. For example, the exterior information detection unit 12030 is connected to a camera unit 12031. The exterior information detection unit 12030 causes the camera unit 12031 to capture images of the exterior of the vehicle and receives the captured images. Based on the received images, the exterior information detection unit 12030 can perform processing such as detecting objects like people, vehicles, obstacles, signs, and text on the road surface, or detecting their distance.

[0183] The camera unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The camera unit 12031 can output this electrical signal as an image or as information related to distance measurement. Furthermore, the light received by the camera unit 12031 can be visible light or non-visible light such as infrared light.

[0184] The in-vehicle information detection unit 12040 detects information related to the interior of the vehicle. For example, the in-vehicle information detection unit 12040 is connected to a driver state detection unit 12041 that detects the driver's state. For example, the driver state detection unit 12041 includes a camera that captures images of the driver. 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, or determine whether the driver is dozing off.

[0185] Based on information about the exterior or interior of the vehicle acquired by the exterior information detection unit 12030 or the interior information detection unit 12040, the microcomputer 12051 can calculate the control target values ​​for the drive force generating device, steering mechanism, or braking device, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform coordinated control aimed at realizing the functions of ADAS (Advanced Driver Assistance System), including collision avoidance or impact mitigation, distance-based following, constant speed driving, collision warning, or lane departure warning.

[0186] In addition, the microcomputer 12051 can control the drive force generating device, steering mechanism, braking device, etc., based on information about the outside or inside of the vehicle obtained by the external information detection unit 12030 or the internal information detection unit 12040, to perform coordinated control such as autonomous driving that enables the vehicle to drive autonomously without the need for driver operation.

[0187] Furthermore, based on information about the vehicle's exterior obtained by the exterior information detection unit 12030, the microcomputer 12051 can output control commands to the body system control unit 12020. For example, the microcomputer 12051 can perform coordinated control aimed at preventing glare by controlling the headlights to switch from high beam to low beam, for example, based on the position of the vehicle in front or oncoming vehicle detected by the exterior information detection unit 12030.

[0188] The sound / image output unit 12052 sends an output signal of at least one of sound and image to an output device capable of visually or audibly notifying vehicle occupants or external to the vehicle. Figure 22 In the example shown, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are shown as output devices. For example, the display unit 12062 may include at least one of an onboard display and a head-up display.

[0189] Figure 23 This is a diagram showing an example of the installation position of the camera unit 12031.

[0190] exist Figure 23 In the middle, the camera unit 12031 includes camera units 12101, 12102, 12103, 12104 and 12105.

[0191] For example, camera units 12101, 12102, 12103, 12104, and 12105 are arranged at the front nose, side mirrors, rear bumper, and trunk lid of vehicle 12100, as well as at the upper part of the windshield inside the passenger compartment. Camera unit 12101 at the front nose and camera unit 12105 at the upper part of the windshield inside the passenger compartment primarily acquire images of the front of vehicle 12100. Camera units 12102 and 12103 at the side mirrors primarily acquire images of the sides of vehicle 12100. Camera unit 12104 at the rear bumper or trunk lid primarily acquires images of the rear of vehicle 12100. Camera unit 12105 at the upper part of the windshield inside the passenger compartment is mainly used to detect vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc., ahead.

[0192] Incidentally, Figure 23 Examples of the shooting ranges of camera units 12101 to 12104 are shown. Camera range 12111 represents the shooting range of camera unit 12101 located on the front nose. Camera ranges 12112 and 12113 represent the shooting ranges of camera units 12102 and 12103 located on the side mirrors, respectively. Camera range 12114 represents the shooting range of camera unit 12104 located on the rear bumper or trunk door. For example, by superimposing the image data captured by camera units 12101 to 12104, a top-down image of the vehicle 12100 viewed from above is obtained.

[0193] At least one of the camera units 12101 to 12104 may have the function of acquiring distance information. For example, at least one of the camera units 12101 to 12104 may be a stereo camera composed of multiple camera elements, or may be a camera element having pixels for phase difference detection.

[0194] For example, based on distance information obtained from cameras 12101 to 12104, microcomputer 12051 can determine the distance to each three-dimensional object within the camera range 12111 to 12114 and how that distance changes over time (relative speed to vehicle 12100), thereby identifying the closest three-dimensional object as the preceding vehicle: this closest three-dimensional object is specifically located on the driving path of vehicle 12100 and is traveling in approximately the same direction as vehicle 12100 at a predetermined speed (e.g., 0 km / h or more). Furthermore, microcomputer 12051 can set a pre-defined distance between the vehicle ahead and the preceding vehicle and execute automatic braking control (including follow-stop control), automatic acceleration control (including follow-start control), etc. Therefore, coordinated control such as autonomous driving, enabling the vehicle to operate autonomously without driver intervention, can be performed.

[0195] For example, based on distance information obtained by cameras 12101 to 12104, microcomputer 12051 can classify three-dimensional object data into three-dimensional object data for two-wheeled vehicles, standard automobiles, large vehicles, pedestrians, utility poles, and other three-dimensional objects, extract the classified three-dimensional object data, and use the extracted three-dimensional object data to automatically avoid obstacles. For example, microcomputer 12051 distinguishes obstacles around vehicle 12100 into obstacles that the driver of vehicle 12100 can visually recognize and obstacles that the driver of vehicle 12100 cannot visually recognize. Then, microcomputer 12051 determines the collision risk indicating the risk of collision with each obstacle. If the collision risk is equal to or greater than a set value and a collision may occur, microcomputer 12051 issues a warning to the driver via audio speaker 12061 or display unit 12062, and executes forced deceleration or evasive steering via drive system control unit 12010. Thus, microcomputer 12051 can assist driving to avoid collisions.

[0196] At least one of the camera units 12101 to 12104 can be an infrared camera that detects infrared light. For example, the microcomputer 12051 can identify a pedestrian by determining whether a pedestrian exists in the images captured by the camera units 12101 to 12104. For example, this pedestrian identification is performed by: extracting feature points from the images captured by the camera units 12101 to 12104, which are infrared cameras; and performing pattern matching processing 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 camera units 12101 to 12104 and thereby identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 to overlay a square outline for emphasis on the identified pedestrian. The sound / image output unit 12052 can also control the display unit 12062 to display an icon or the like representing a pedestrian at a desired location.

[0197] An example of a vehicle control system to which the technology according to this disclosure is applicable has been described above. The technology according to this disclosure is applicable to the camera unit 12031 in the above configuration. Applying the technology according to this disclosure to the camera unit 12031 can further improve the overvoltage withstand capability of the resistive element and improve the characteristics of the protection circuit.

[0198] <18. Other embodiments> This technology is not limited to the above embodiments and can be modified in various ways without departing from the protection scope of this technology. For example, it is also possible to combine the optical detection device and the ranging system according to two or more embodiments of the first to sixteenth embodiments.

[0199] According to a first embodiment of the present disclosure, the photodetector includes: an avalanche photodiode, wherein a first fixed voltage is applied to one of the anode region and the cathode region to multiply the charge carriers generated by the incident photons; a protection circuit including a resistive element electrically connected in series with the other of the anode and cathode regions to protect the internal circuit from overcurrent; and a first electrical conductor electrically connected in parallel with the resistive element. When photons with a higher than expected light intensity are incident on the avalanche photodiode 11, the photodetector with this configuration can absorb and reduce the overcurrent flowing through the resistive element. This protects the resistive element and increases its tolerance. Consequently, the protection circuit is protected, and the overcurrent tolerance of the photodetector is improved.

[0200] In the optical detection device according to the second embodiment of this disclosure, the first electrical conductor of the optical detection device according to the first embodiment is positioned opposite to the second electrical conductor, an insulator is inserted between the first and second electrical conductors, and the second electrical conductor is electrically connected to a second fixed voltage. Furthermore, in the optical detection device, the first electrical conductor, the insulator, and the second electrical conductor constitute a capacitor element to protect the resistive element from overcurrent. This configuration of the photodetector allows the capacitive element to absorb and reduce overcurrent flowing through the resistive element. This protects the resistive element and increases its tolerance. Consequently, the protection circuit is protected, and the photodetector's tolerance to overcurrent is improved.

[0201] In the optical detection device according to the third embodiment, the resistive element of the optical detection device according to the first embodiment includes polysilicon, metal, or insulated gate field-effect transistor. This configuration of the photodetector allows the capacitive element to absorb and reduce overcurrent flowing through the resistive element, regardless of the material or structure of the resistive element. This protects the resistive element and increases its tolerance. Consequently, the protection circuit is protected, and the photodetector's overcurrent tolerance is increased.

[0202] In the photodetector according to the fourth embodiment of this disclosure, the resistive element of the photodetector according to the first embodiment has the same polarity or a different polarity from another element in the anode and cathode regions of the avalanche photodiode. This configuration of the photodetector allows the capacitive element to absorb and reduce overcurrent flowing through the resistive element, regardless of the polarity of the resistive element. This protects the resistive element and increases its tolerance. Consequently, the protection circuit is protected, and the photodetector's tolerance to overcurrent is improved.

[0203] The ranging system according to the fifth embodiment of this disclosure includes an optical detection device and a circuit device. The photodetector includes: an avalanche photodiode, wherein a first fixed voltage is applied to one of the anode and cathode regions to multiply the charge carriers generated by the incident photons; a protection circuit including a resistive element electrically connected in series with the other in the anode and cathode regions to protect the internal circuit from overcurrent; and a first electrical conductor electrically connected in parallel with the resistive element. The circuitry includes: an internal circuit electrically connected to the avalanche photodiode via a protection circuit, the internal circuit constituting a readout circuit for reading out multiplied charge carriers; and a time measurement circuit electrically connected to the internal circuit for measuring the time of flight of light. In a manner similar to the optical detection device according to the first embodiment, the ranging system having this configuration can improve the optical detection device's tolerance to overcurrent.

[0204] <Based on the structure of this technology> This technology has the following configuration. According to this technology with the following configuration, the protection circuit can be protected, and the tolerance of the photodetector to overcurrent can be improved. (1) The optical detection device includes: An avalanche photodiode, wherein a first fixed voltage is applied to one of the anode and cathode regions to multiply the carriers generated by incident photons; A protection circuit, comprising a resistive element electrically connected in series with another element in the anode region and the cathode region, to protect the internal circuitry from overcurrent; and The first electrical conductor is electrically connected in parallel with the resistive element. (2) According to the optical detection device described in (1), The first electrical conductor is positioned opposite the second electrical conductor, an insulator is inserted between the first electrical conductor and the second electrical conductor, and the second electrical conductor is electrically connected to a second fixed voltage. (3) According to the optical detection device described in (2), The first electrical conductor, the insulator, and the second electrical conductor constitute a capacitor element to protect the resistive element from overcurrent. (4) According to any one of (1) to (3), the light detection device, When viewed from the thickness direction of the resistive element, the first electrical conductor is configured to overlap with the resistive element. (5) According to any one of (1) to (4), the light detection device, The first electrical conductor is electrically connected in parallel with the middle portion of the resistive element along the length of the resistance. (6) According to any one of (1) to (4), the light detection device, In this configuration, a plurality of the first electrical conductors are arranged along the resistance length direction of the resistive element. (7) According to any one of (1) to (4), the light detection device, Wherein, the resistive element is divided into multiple segmented resistive elements along the length direction of the resistor, and The first electrical conductor connects the plurality of segmented resistive elements in series. (8) According to any one of (1) to (4), the light detection device, Specifically, when viewed from the thickness direction of the resistive element, the center of the first electrical conductor is connected to the resistive element. (9) According to any one of (1) to (4), the light detection device, The first electrical conductor forms a capacitor element by stacking multiple electrical conductors in the thickness direction. (10) According to any one of (1) to (9), the light detection device, Specifically, when viewed from the thickness direction of the resistive element, the resistive element is configured to overlap with the avalanche photodiode. (11) According to any one of (1) to (10), the light detection device, The avalanche photodiode side of the resistive element is either directly electrically connected to the semiconductor or indirectly electrically connected to the semiconductor through a metal component. (12) According to any one of (1) to (11), the light detection device, The resistive element comprises polycrystalline silicon or metal. (13) According to any one of (1) to (11), the light detection device, The resistive element includes an insulated-gate field-effect transistor. (14) The light detection device according to any one of (1) to (13) comprises: A first substrate, wherein the avalanche photodiode is disposed therein; and The second substrate is formed by stacking the first substrate on top of the second substrate, and the resistive element is disposed within the second substrate. (15) The light detection device according to any one of (1) to (13) comprises: A first substrate, wherein the avalanche photodiode and the resistive element are disposed in the first substrate. (16) The light detection device according to any one of (1) to (13) comprises: first matrix; and A second substrate, wherein the first substrate is stacked on top of the second substrate. The avalanche photodiode is disposed in the first substrate. A portion of the resistive element is disposed in the first substrate, and Another portion of the resistive element is disposed in the second substrate. (17) According to any one of (1) to (16) the light detection device, The resistive element has the same polarity as the other of the anode and cathode regions of the avalanche photodiode. (18) According to any one of (1) to (16) the light detection device, The resistive element has a polarity different from that of the other of the anode and cathode regions of the avalanche photodiode. (19) According to any one of (1) to (18) the light detection device, The protection circuit further includes a clamping element, which is electrically connected in series between the resistive element and the internal circuit. (20) Distance measuring system, including: Optical detection device; and Circuit device, The optical detection device includes: An avalanche photodiode, wherein a first fixed voltage is applied to one of the anode region and the cathode region to multiply the carriers generated by the incident photons; A protection circuit, comprising a resistive element electrically connected in series with another element in the anode region and the cathode region, to protect the internal circuitry from overcurrent; and The first electrical conductor is electrically connected in parallel with the resistive element, and The circuit device includes: The internal circuit, electrically connected to the avalanche photodiode via the protection circuit, constitutes a readout circuit for reading out the multiplied charge carriers; and A time measurement circuit, which is electrically connected to the internal circuit, measures the time of flight of light.

[0206] This application claims priority to Japanese priority patent application JP2024-036956, filed with the Japan Patent Office on March 11, 2024, the entire contents of which are incorporated herein by reference.

[0207] Those skilled in the art should understand that various modifications, combinations, sub-combinations and alterations can be made according to design requirements and other factors, as long as they are within the scope of protection of the appended claims or their equivalents.

Claims

1. A light detection device, comprising: An avalanche photodiode, wherein a first fixed voltage is applied to one of the anode region and the cathode region to multiply the carriers generated by the incident photons; A protection circuit includes a resistive element electrically connected in series with another element in the anode region and the cathode region to protect the internal circuitry from overcurrent. as well as The first electrical conductor is electrically connected in parallel with the resistive element.

2. The optical detection device according to claim 1, in, The first electrical conductor is positioned opposite the second electrical conductor, and an insulator is inserted between the first electrical conductor and the second electrical conductor. The second electrical conductor is electrically connected to a second fixed voltage.

3. The optical detection device according to claim 2, in, The first electrical conductor, the insulator, and the second electrical conductor constitute a capacitor element to protect the resistive element from overcurrent.

4. The optical detection device according to claim 1, in, When viewed from the thickness direction of the resistive element, the first electrical conductor is configured to overlap with the resistive element.

5. The optical detection device according to claim 1, in, The first electrical conductor is electrically connected in parallel with the middle portion of the resistive element along the length of the resistance.

6. The optical detection device according to claim 1, in, A plurality of the first electrical conductors are arranged along the resistance length direction of the resistive element.

7. The optical detection device according to claim 1, in, The resistive element is divided into multiple parts along its length, and The first electrical conductor will be divided into multiple resistive elements that are connected in series.

8. The optical detection device according to claim 1, in, When viewed from the thickness direction of the resistive element, the center of the first electrical conductor is connected to the resistive element.

9. The optical detection device according to claim 1, in, The first electrical conductor forms a capacitor element by stacking multiple electrical conductors in the thickness direction.

10. The optical detection device according to claim 1, in, When viewed from the thickness direction of the resistive element, the resistive element is configured to overlap with the avalanche photodiode.

11. The optical detection device according to claim 1, in, The avalanche photodiode side of the resistive element is either directly electrically connected to the semiconductor or indirectly electrically connected to the semiconductor through a metal component.

12. The optical detection device according to claim 1, in, The resistive element comprises polycrystalline silicon or metal.

13. The optical detection device according to claim 1, in, The resistive element includes an insulated-gate field-effect transistor.

14. The optical detection device according to claim 1, comprising: A first substrate, wherein the avalanche photodiode is disposed in the first substrate; and The second substrate is formed by stacking the first substrate on top of the second substrate, and the resistive element is disposed within the second substrate.

15. The optical detection device according to claim 1, comprising: A first substrate, wherein the avalanche photodiode and the resistive element are disposed in the first substrate.

16. The optical detection device according to claim 1, comprising: First matrix; and A second substrate, wherein the first substrate is stacked on top of the second substrate. The avalanche photodiode is disposed in the first substrate. A portion of the resistive element is disposed in the first substrate, and Another portion of the resistive element is disposed in the second substrate.

17. The optical detection device according to claim 1, in, The resistive element has the same polarity as the other of the anode and cathode regions of the avalanche photodiode.

18. The optical detection device according to claim 1, in, The resistive element has a polarity different from that of the other of the anode and cathode regions of the avalanche photodiode.

19. The optical detection device according to claim 1, in, The protection circuit also includes a clamping element, which is electrically connected in series between the resistive element and the internal circuit.

20. A ranging system, including: Optical detection device; and Circuit device, The optical detection device includes: An avalanche photodiode, wherein a first fixed voltage is applied to one of the anode region and the cathode region to multiply the carriers generated by the incident photons; A protection circuit, comprising a resistive element electrically connected in series with another element in the anode region and the cathode region, to protect the internal circuitry from overcurrent; and The first electrical conductor is electrically connected in parallel with the resistive element, and The circuit device includes: The internal circuit, electrically connected to the avalanche photodiode via the protection circuit, constitutes a readout circuit for reading out the multiplied charge carriers; and A time measurement circuit, which is electrically connected to the internal circuit, measures the time of flight of light.

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