Photoelectric conversion device

Abstract

To provide a technique for supporting microfabrication of a circuit in a photoelectric conversion device having a structure of three or more layers.SOLUTION: A photoelectric conversion device comprises: a pixel including an avalanche photodiode, a pixel circuit for performing signal processing from the avalanche photodiode, and a signal processing circuit for performing signal processing from the pixel circuit; and a control signal generation circuit which generates a first control signal for controlling operation of the pixel circuit and a second control signal for controlling operation of the signal processing circuit. An output terminal of the avalanche photodiode is connected with the pixel circuit, a plurality of pixels is disposed in a pixel region, and the control signal generation circuit is disposed in a peripheral region provided in a periphery of the pixel region. First wiring supplying the first control signal to the pixel circuit is provided in a first circuit layer, and the first wiring is connected with the control signal generation circuit in the peripheral region.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The technology of the present disclosure relates to a photoelectric conversion device. [Background technology]

[0002] There is known a photoelectric conversion device that can detect weak light at the single photon level by using avalanche multiplication. Patent Document 1 discloses a photoelectric conversion device in which a sensor chip on which a plurality of pixels are arranged and a circuit chip on which a circuit for performing signal processing is formed are both electrically connected in a stacked structure. It is disclosed that avalanche diodes in which electric charges undergo avalanche multiplication are used for the pixels in the sensor chip of this photoelectric conversion device.

[0003] Patent Document 2 proposes the configuration of a photoelectric conversion device having a three or more layer structure equipped with an avalanche photodiode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2017 / 0186798 [Patent Document 2] JP 2022-113123 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the structures of the photoelectric conversion devices described in Patent Documents 1 and 2, there is room for improvement in terms of miniaturizing the circuits in the circuit layer laminated on the photodiode layer.

[0006] The technique of the present disclosure has been made in view of the above-mentioned problems, and has an object to provide a technique for supporting miniaturization of circuits in a photoelectric conversion device having a structure of three or more layers. [Means for solving the problem]

[0007] In order to achieve the above object, the photoelectric conversion device according to the present disclosure includes a pixel having an avalanche photodiode, a pixel circuit that performs processing using a signal output from the avalanche photodiode, and a signal processing circuit that performs processing using the signal output from the pixel circuit, and a control signal generation circuit that generates a first control signal that controls an operation of the pixel circuit and a second control signal that controls an operation of the signal processing circuit, wherein a second circuit layer in which the signal processing circuit and the control signal generation circuit are arranged, a first circuit layer in which the pixel circuit is arranged, and a photodiode layer in which the avalanche photodiode is arranged are stacked in this order, an output terminal of the avalanche photodiode is connected to the pixel circuit, a plurality of the pixels are arranged in a pixel region, the control signal generation circuit is arranged in a peripheral region provided around the pixel region, and a first wiring that supplies the first control signal to the pixel circuit is provided in the first circuit layer, and the first wiring is connected to the control signal generation circuit in the peripheral region. Effect of the Invention

[0008] According to the technique of the present disclosure, it is possible to provide a technique for supporting miniaturization of circuits in a photoelectric conversion device having a structure of three or more layers. [Brief description of the drawings]

[0009] [Figure 1] Schematic diagram of a photoelectric conversion device according to an embodiment. [Diagram 2] 1 is a schematic diagram of a photodiode layer of a photoelectric conversion device according to an embodiment; [Diagram 3] 1 is a schematic diagram of a first circuit layer of a photoelectric conversion device according to an embodiment; [Figure 4] 1 is a schematic diagram of a second circuit layer of a photoelectric conversion device according to an embodiment; [Diagram 5] FIG. 1 is a schematic diagram showing the operation of a photodiode in a photoelectric conversion device according to an embodiment; [Figure 6]FIG. 1 is a schematic diagram showing a circuit configuration of a photoelectric conversion device according to a first embodiment; [Figure 7] FIG. 1 is a schematic diagram showing a circuit configuration of a photoelectric conversion device according to a conventional technique. [Figure 8] FIG. 1 is a schematic diagram showing a circuit configuration of a photoelectric conversion device according to a modified example of the first embodiment. [Figure 9] FIG. 13 is a schematic diagram showing a circuit configuration of a photoelectric conversion device according to a second embodiment. [Figure 10] FIG. 13 is a schematic diagram showing a circuit configuration of a photoelectric conversion device according to a third embodiment. [Figure 11] FIG. 10 is a diagram for explaining a photoelectric conversion system according to a fourth embodiment. [Figure 12] FIG. 13 is a diagram illustrating a photoelectric conversion system and a moving object according to a fifth embodiment. [Figure 13] FIG. 13 is a diagram for explaining a range image sensor according to a sixth embodiment. [Figure 14] FIG. 13 is a diagram for explaining an endoscopic surgery system according to a seventh embodiment. [Figure 15] FIG. 13 is a diagram for explaining smart glasses according to an eighth embodiment. [Figure 16] FIG. 13 is a diagram illustrating an electronic device according to a ninth embodiment. [Figure 17] FIG. 17 is a diagram for explaining an X-ray CT apparatus according to the tenth embodiment. [Figure 18] FIG. 11 is a diagram for explaining an apparatus according to an eleventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the technology of the present disclosure will be described in detail with reference to the drawings. The embodiments shown below are intended to embody the technical ideas of the technology of the present disclosure, and do not limit the technology of the present disclosure. The size and positional relationship of the components shown in each drawing may be exaggerated to clarify the explanation. In the following explanation, the same configurations may be assigned the same numbers and explanations may be omitted.

[0011] In this specification, a planar view refers to a view from a direction perpendicular to the light incidence surface of the semiconductor layer. A cross-sectional view refers to a view from a direction perpendicular to the light incidence surface of the semiconductor layer. When the light incidence surface of the semiconductor layer is a rough surface when viewed microscopically, the planar view is defined based on the light incidence surface of the semiconductor layer when viewed macroscopically. The components of each embodiment can be added to another embodiment or replaced with the components of another embodiment. The sizes and positional relationships of the components shown in each drawing may be exaggerated to clarify the explanation.

[0012] The following embodiments relate in particular to a photoelectric conversion device including a SPAD (Single Photon Avalanche Diode) that counts the number of photons incident on the avalanche photodiode. The photoelectric conversion device includes at least an avalanche photodiode. In the photoelectric conversion devices described in the following embodiments, the anode of the avalanche photodiode (APD) is set to a fixed potential, and a signal is taken out from the cathode side. Therefore, the first conductive type semiconductor region having charges of the same polarity as the signal charge as the majority carriers is an N-type semiconductor region, and the second conductive type semiconductor region having charges of a polarity opposite to that of the signal charge as the majority carriers is a P-type semiconductor region.

[0013] The following embodiments can also be applied when the cathode of the APD is at a fixed potential and the signal is taken out from the anode side. In this case, the first conductivity type semiconductor region having charges of the same polarity as the signal charge as the majority carrier is a P-type semiconductor region, and the second conductivity type semiconductor region having charges of a different polarity than the signal charge as the majority carrier is an N-type semiconductor region. In the following, a case where one node of the APD is at a fixed potential will be described, but the potentials of both nodes may fluctuate.

[0014] First, a configuration common to each embodiment of a photoelectric conversion device and a driving method thereof will be described with reference to FIGS. 1 to 5. FIG.

[0015] FIG. 1 is a diagram showing an overall image of a photoelectric conversion device 100. The photoelectric conversion device 100 has a configuration in which a first substrate 110, a second substrate 210, and a third substrate 310 are stacked on top of each other. The first substrate 110 is also called a sensor chip, and has a pixel region 12 in which pixels having a photoelectric conversion unit are arranged two-dimensionally. In addition, a peripheral region 13 is provided between the pixel region 12 and the chip end of the photoelectric conversion device 100. The second substrate 210 is also called a pixel circuit chip, and has a pixel circuit region 22 in which a pixel control circuit that processes a signal from the photoelectric conversion unit is arranged. The third substrate 310 is also called a signal processing chip, and has a signal processing circuit region 32 in which a signal processing circuit that processes a signal from the pixel control circuit is arranged.

[0016] (First board) 2 is a configuration diagram of the first substrate 110. The first substrate 110 is provided with a pixel region 12 in which pixels 101 having photoelectric conversion units 102 including avalanche photodiodes (hereinafter, APDs) are arranged two-dimensionally. The pixels 101 may be arranged one-dimensionally in the pixel region 12. Details of the photoelectric conversion units 102 will be described later.

[0017] The pixel 101 is typically a pixel for forming an image, but when used for TOF (Time of Flight), it does not necessarily have to form an image. In other words, the pixel 101 may be an element for measuring the time when light arrives and the amount of light.

[0018] (Second board) FIG. 3 is a configuration diagram of the second substrate 210. The second substrate 210 has a pixel control circuit 201 and a vertical scanning circuit 202. The pixel circuit region 22 in which at least the pixel control circuit 201 is provided is disposed at a position overlapping the pixel region 12 of the first substrate 110 shown in FIG. 2. The pixel control circuit 201 is electrically connected to the photoelectric conversion unit 102 of the first substrate 110 via a connection wiring provided for each pixel. In addition, the pixel control circuit 201 is electrically connected to the signal processing circuit 301 of the third substrate 310 via each connection wiring. The pixel control circuit 201 is a pixel circuit that performs processing using a signal output from the photoelectric conversion unit 102 of the pixel. For example, the pixel control circuit 201 performs processing such as a quenching operation of the avalanche photodiode of the photoelectric conversion unit 102 and waveform shaping of the signal output from the photoelectric conversion unit 102.

[0019] The vertical scanning circuit 202 receives a pixel control signal (also referred to as a pixel clock (PCLK)) supplied from the control signal generating circuit 302 on the third substrate 310, and supplies the pixel control signal to each pixel control circuit 201. The vertical scanning circuit 202 uses logic circuits such as a shift register and an address decoder.

[0020] (Third board) Fig. 4 is a configuration diagram of the third substrate 310. The third substrate 310 has a signal processing circuit 301, a control signal generating circuit 302, a vertical scanning circuit 303, a horizontal scanning circuit 304, and a signal line 305. A signal processing circuit region 32 in which at least the signal processing circuit 301 is provided is disposed at a position overlapping the pixel region 12 of the first substrate 110 shown in Fig. 2 and the pixel circuit region 22 of the second substrate 210 shown in Fig. 3.

[0021] The signal processing circuit 301 performs processing using a signal output from the pixel control circuit 201. For example, the signal processing circuit 301 has a count circuit that performs count processing of a pulse signal output from the pixel control circuit 201, a memory that holds a count value output by the count circuit, and the like. The vertical scanning circuit 303 receives a control signal supplied from the control signal generation circuit 302, and supplies a control signal to each signal processing circuit 301. In order to read out a signal from the signal processing circuit 301, the horizontal scanning circuit unit 203 inputs a control pulse to the signal processing circuit 301, which sequentially selects each column via a signal line 305.

[0022] The third substrate 310 may be provided with a processing circuit that performs image processing on the signal read out from the signal processing circuit 301 and performs processing such as noise removal and white balance adjustment on the image data. When the photoelectric conversion device 100 is used as a distance measurement device, for example, a processing circuit that creates a histogram based on a Time to Digital Converter (TDC) circuit or information obtained from the TDC circuit and performs distance calculation may be provided.

[0023] In a histogram, the horizontal axis represents time-related classes (bins), and the vertical axis represents the frequency of each class. The frequency is the number of times light is received in a given light-receiving time. Furthermore, the histogram contains a mixture of counts based on reflected light and ambient light. Therefore, a given threshold is set to separate the counts of reflected light components from the counts of ambient light components. The distance between the distance measurement device and the object to be measured is calculated from the light arrival time corresponding to the reflected light component.

[0024] The third substrate 310 may also be provided with a DSP (Digital Signal Processor) that functions as a processing unit that executes a program stored in a memory and executes various processes using a trained model created by machine learning. For example, the trained model is created by machine learning using a deep neural network (DNN). For example, the trained model may be designed based on parameters generated by inputting an input signal corresponding to an output from the pixel region 12 and training data associated with a label for the input signal into a predetermined machine learning model. The predetermined machine learning model may also be a training model that uses a multi-layer neural network.

[0025] Data output from the photoelectric conversion device 100 is input to an application processor (not shown) that processes display, user interface, and the like. The application processor is configured using, for example, a CPU (Central Processing Unit) and the like, and executes an operating system, various application software, and the like. This application processor may be equipped with functions such as a GPU (Graphics Processing Unit) and a baseband processor. The application processor performs various processes on the input image data and calculation results as necessary, displays them to the user, and transmits them to an external cloud server via a predetermined network.

[0026] The network may be any of various networks, such as the Internet, a wired LAN (Local Area Network), a wireless LAN, a mobile communication network, Bluetooth (registered trademark), etc. The destination of the image data and the calculation results is not limited to a cloud server, but may be any of various information processing devices (systems) having communication functions, such as a single operating server, a file server storing various data, or a communication terminal such as a mobile phone.

[0027] 5A and 5B are diagrams illustrating a relationship between the operation of the APD included in the photoelectric conversion unit 102 and an output signal. As shown in Fig. 5A, in one pixel of the photoelectric conversion device 100, the APD 103 of the photoelectric conversion unit 102, the quench element 204 of the pixel control circuit 201, and the waveform shaping unit 205 are electrically connected to each other. Here, the input side of the waveform shaping unit 205 is referred to as nodeA, and the output side is referred to as nodeB. Fig. 5B illustrates an example of a waveform change at nodeA in Fig. 5A and a waveform change at nodeB in Fig. 5A.

[0028] As shown in Fig. 5B, between time t0 and time t1, a potential difference of VH-VL is applied to the APD 103 in Fig. 5A. When a photon is incident on the APD 103 at time t1, avalanche multiplication occurs in the APD 103, and avalanche multiplication is generated in the quench element 204. A doubled current flows, and the voltage at nodeA drops and exceeds the decision threshold. Then, when the amount of voltage drop becomes even larger and the potential difference applied to APD 103 becomes smaller, at time t2, avalanche multiplication of APD 103 stops, and the voltage level at nodeA does not drop by more than a certain value. After that, between time t2 and time t3, a current that compensates for the voltage drop from voltage VL flows to nodeA, and the voltage at nodeA rises and exceeds the decision threshold. Then, at time t3, nodeA is settled to its original potential level. At this time, the part of the output waveform at nodeA that exceeds a certain threshold is shaped by waveform shaping unit 205 and then output as a signal at nodeB.

[0029] (First embodiment) Next, the photoelectric conversion device according to the first embodiment will be described with reference to Fig. 6. Fig. 6 is a block diagram showing an example of a circuit of the photoelectric conversion device 100 according to this embodiment. Note that in the figure, some components of the photoelectric conversion device 100 will be omitted for the description.

[0030] As shown in FIG. 6, the photoelectric conversion device 100 includes a PD (Photo Diode). The photoelectric conversion device 100 includes a first substrate 110 as a first circuit layer, a second substrate 210 as a first circuit layer, and a third substrate 310 as a second circuit layer. Thus, in the photoelectric conversion device 100, the second circuit layer (third substrate 310), the first circuit layer (second substrate 210), and the photodiode layer (first substrate 110) are laminated in this order. The side on which the first substrate 110 is present is the side on which light is incident on the photoelectric conversion device 100. In the pixel region 12 of the photoelectric conversion device 100, pixels 121, 122, 123, and 124 are arranged. In the figure, four pixels are arranged in one direction, but in the pixel region 12, pixels having the same configuration as these pixels are arranged two-dimensionally.

[0031] 6, on the first substrate 110, APDs 1211, 1221, 1231, and 1241 are provided for the pixels 121, 122, 123, and 124, respectively. Furthermore, on the second substrate 210, the pixels 121, 122, 123, and 124 are provided with pixel control circuits 2011, 2012, 2013, and 2014. The pixel control circuits 2011, 2012, 2013, and 2014 control the operation of the APDs 1211, 1221, 1231, and 1241 and process signals output from the APDs 1211, 1221, 1231, and 1241.

[0032] The second substrate 210 is a substrate on which elements, such as quenching elements, having a higher withstand voltage than elements arranged on the third substrate are arranged. In addition, in Fig. 6, the second substrate 210 is provided with wiring 2101 that supplies a control signal (PCLK) to the pixel control circuits 2011, 2012, 2013, and 2014. The wiring 2101 is provided on the second substrate 210 in the pixel region 12. The wiring 2101 is a first wiring that supplies a first control signal, which controls the operation of the pixel circuit, to the pixel circuit.

[0033] Further, the pixels 121 and 123 are provided with buffers 1212 and 1232, respectively, for adjusting the timing of the control signal transmitted by the wiring 2101. The wiring 2101 is provided with the buffers 1212 and 1232 at a constant pitch according to the pixel unit. However, which pixels in the wiring 2101 are provided with the buffers at the constant pitch may be appropriately determined. In this embodiment, the multiple pixels include at least one pixel in which the wiring 2101 is not provided with a buffer and at least one pixel in which the wiring 2101 is provided with a buffer. Furthermore, the wiring 2101 is connected to the control signal generating circuit 302 of the third substrate 310 in the peripheral region 13.

[0034] The third substrate 310 is a substrate on which elements having a lower withstand voltage than elements arranged on the second substrate 210, such as a count circuit or a logic circuit of a memory circuit, are arranged. In FIG. 6, as an example, the third substrate 310 is provided with a control signal generating circuit 302 in the peripheral region 13. Furthermore, on the third substrate 310, the pixels 121, 122, 123, and 124 are provided with signal processing circuits 3011, 3012, 3013, and 3014. The signal processing circuits 3011, 3012, 3013, and 3014 perform counting processing using signals output from the pixel control circuits 2011, 2012, 2013, and 2014.

[0035] The third substrate 310 is also provided with wiring 3101 that supplies a reset signal for the count circuit to the signal processing circuits 3011, 3012, 3013, and 3014. The third substrate 310 is also provided with wiring 3102 that supplies an enable signal for the count circuit to the signal processing circuits 3011, 3012, 3013, and 3014. The third substrate 310 is also provided with wiring 3103 that supplies a read signal for the count value to the signal processing circuits 3011, 3012, 3013, and 3014. The wirings 3101, 3102, and 3103 are second wirings that supply a second control signal for controlling the operation of the signal processing circuit to the signal processing circuit.

[0036] Furthermore, the pixel 121 is provided with buffers 1215, 1216, and 1217 for adjusting the timing of control signals transmitted through the wirings 3101, 3102, and 3103. Similarly, the pixel 123 is provided with buffers 1235, 1236, and 1237 for adjusting the timing of control signals transmitted through the wirings 3101, 3102, and 3103. It may be appropriately determined which pixels the buffers 1215, 1216, 1217, 1235, 1236, and 1237 are provided in. In other words, the pitches at which these buffers are provided on the third substrate 310 may be different from each other.

[0037] Here, Fig. 7 shows an example of a photoelectric conversion device 100c in the prior art. The photoelectric conversion device 100c includes a first substrate 110c, a second substrate 210c, and a third substrate 310c. In addition, pixels 121c, 122c, 123c, and 124c are arranged in a pixel region 12c of the photoelectric conversion device 100c. In the figure, four pixels are arranged in one direction, but in the pixel region 12, pixels having the same configuration as these pixels are arranged two-dimensionally. In addition, a control signal generating circuit 302c is provided in a peripheral region 13c of the photoelectric conversion device 100c.

[0038] The pixels 121c, 122c, 123c, and 124c respectively include APDs 1211c, 1221c, 1231c, and 1241c, pixel control circuits 2011c, 2012c, 2013c, and 2014c, and signal processing circuits 3011c, 3012c, 3013c, and 3014c. The APD, pixel control circuit, and signal processing circuit in Fig. 7 correspond to the APD, pixel control circuit, and signal processing circuit in Fig. 6. The pixel 121c also includes buffers 1212c, 1215c, 1216c, and 1217c, and the pixel 123c also includes buffers 1232c, 1235c, 1236c, and 1237c. Buffers 1212c, 1215c, 1216c, 1217c, 1232c, 1235c, 1236c, and 1237c correspond to buffers 1212, 1215, 1216, 1217, 1232, 1235, 1236, and 1237 in Figure 6.

[0039] In the photoelectric conversion device 100c, a third substrate 310c is provided with wiring 2101c that supplies a control signal (PCLK) to the pixel control circuits 2011c, 2012c, 2013c, and 2014c. Similarly to the above-described photoelectric conversion device 100, the third substrate 310c is provided with wiring 3101c, 3102c, and 3103c that correspond to the wiring 3101, 3102, and 3103 in FIG.

[0040] For this reason, in the third substrate 310c of the photoelectric conversion device 100c, the arrangement density of elements and the arrangement density of wiring are higher than those of the third substrate 310 of the photoelectric conversion device 100, and the number of elements that can be arranged in each pixel arranged in the pixel region may be reduced. Also, in order to supply control signals to the pixel control circuits 2011c, 2012c, 2013c, and 2014c, it is necessary to provide wiring for transferring signals between the third substrate 310c and the second substrate 210c in each pixel. Therefore, in the photoelectric conversion device 100c, the pitch of the connection between the third substrate 310c and the second substrate 210c becomes dense, which may reduce the number of elements that can be arranged in each pixel arranged in the pixel region.

[0041] On the other hand, according to the photoelectric conversion device 100 of this embodiment, the wiring 2101 for signals supplied to the pixel control circuit 201 provided on the second substrate 210 is provided on the second substrate 210 instead of the third substrate 310. In this manner, when a circuit for processing signals from the APDs 1211, 1221, 1231, and 1241 is provided on the second substrate 210, the wiring for supplying a control signal to the circuit is provided on the same second substrate 210, not on the third substrate 310. This allows a larger area to be secured on the third substrate 310 for providing wiring, elements, and the like, and allows further miniaturization of the components of the third substrate 310.

[0042] (Variation 1) Next, a description will be given of a modification of the photoelectric conversion device 100 according to the first embodiment. In the following description, the same components as those in the photoelectric conversion device 100 described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0043] FIG. 8 is a block diagram showing an example of a circuit of a photoelectric conversion device 150 according to this modification. In FIG. 8, some components of the photoelectric conversion device 150 are omitted for explanation. As shown in FIG. 8, in the first substrate 110 of the photoelectric conversion device 150, pixels 121, 122, 123, and 124 are provided in the pixel region 12. The pixels 121, 122, 123, and 124 include APDs 1211, 1221, 1231, and 1241, respectively. A voltage Va is applied to the anode terminals of the APDs 1211, 1221, 1231, and 1241. The cathode terminals of the APDs 1211, 1221, 1231, and 1241 are connected to MOSFETs (Metal-oxide Semiconductor Field Effect Transistors) 2011a, which are quenching elements of the second substrate 210.

[0044] In the second substrate 210 of the photoelectric conversion device 150, MOSFETs 2011a, 2012a, 2013a, and 2014a constituting a pixel control circuit are provided in the pixel region 12. The drains of the MOSFETs 2011a, 2012a, 2013a, and 2014a are connected to the cathode terminals of the APDs 1211, 1221, 1231, and 1241. A voltage Vdd is applied to the sources of the MOSFETs 2011a, 2012a, 2013a, and 2014a. The MOSFETs 2011a, 2012a, 2013a, and 2014a suppress the voltage supplied to the APDs 1211, 1221, 1231, and 1241 to perform a quenching operation that suppresses avalanche multiplication. In addition, in the pixel region 12, processing circuits 2011b, 2012b, 2013b, and 2014b including waveform shaping circuits that perform waveform shaping processing of signals output from the APDs 1211, 1221, 1231, and 1241 are provided.

[0045] The APDs 1211, 1221, 1231, and 1241 generate pairs of charges according to incident light through photoelectric conversion. One of the two nodes of the APDs 1211, 1221, 1231, and 1241 is connected to a power supply line that supplies a drive voltage Va (first voltage). The other of the two nodes of the APDs 1211, 1221, 1231, and 1241 is connected to a power supply line that supplies a drive voltage Vdd (second voltage) that is higher than the voltage Va supplied to the anode.

[0046] In FIG. 8, one node of the APDs 1211, 1221, 1231, and 1241 is an anode terminal, and the other node of the APDs 1211, 1221, 1231, and 1241 is a cathode terminal. A reverse bias voltage is supplied to the anode and cathode terminals of the APDs 1211, 1221, 1231, and 1241 so that the APDs 1211, 1221, 1231, and 1241 perform avalanche multiplication. By supplying such a voltage, the input The electric charges generated by the incident light undergo avalanche multiplication, generating an avalanche current. In Fig. 8, the cathode terminals, which are the output terminals of the APDs 1211, 1221, 1231, and 1241, are connected to the MOSFETs 2011a, 2012a, 2013a, and 2014a that constitute the pixel control circuit. However, the anode terminals of the APDs 1211, 1221, 1231, and 1241 may be connected to the MOSFETs 2011a, 2012a, 2013a, and 2014a as output terminals.

[0047] In addition, there is a Geiger mode in which the voltage difference between the anode terminal and the cathode terminal is greater than the breakdown voltage when a reverse bias voltage is supplied, and a linear mode in which the voltage difference between the anode terminal and the cathode terminal is close to or less than the breakdown voltage when a reverse bias voltage is supplied.

[0048] An APD operated in Geiger mode is called a SPAD. For example, the voltage Va is −30 V and the voltage Vdd is 1 V. The APDs 1211, 1221, 1231, and 1241 may be operated in either linear mode or Geiger mode. In the case of a SPAD, the voltage difference is larger than that of a linear mode APD, and the effect of withstanding voltage is more pronounced, so it is preferable that the APDs 1211, 1221, 1231, and 1241 are SPADs.

[0049] Moreover, in the second substrate 210, wiring 2101 for supplying a control signal (PCLK) to the gates of the MOSFETs 2011a, 2012a, 2013a, and 2014a is provided in the peripheral region 13. Therefore, the MOSFETs 2011a, 2012a, 2013a, and 2014a, which are quenching elements, are controlled by the control signal supplied by the wiring 2101 to a high resistance state and a low resistance state having a resistance value lower than that of the high resistance state.

[0050] The third substrate 310 has a control signal generating circuit 302 in the peripheral region 13. In addition, in the third substrate 310, the pixels 121, 122, 123, and 124 have count circuits 3011a, 3012a, 3013a, and 3014a and memory circuits 3011b, 3012b, 3013b, and 3014b that constitute a signal processing circuit. The count circuit 3011a has a flip-flop 3011f for performing count processing of the signal output from the processing circuit 2011b. The count circuits 3012a, 3013a, and 3014a also have a flip-flop similar to the flip-flop 3011f.

[0051] The third substrate 310 is also provided with wiring 3101 for supplying reset signals to the count circuits 3011a, 3012a, 3013a, and 3014a. The third substrate 310 is also provided with wiring 3102 for supplying enable signals to the count circuits 3011a, 3012a, 3013a, and 3014a. The third substrate 310 is also provided with wiring 3104 for supplying write signals for writing count values ​​output from the count circuits 3011a, 3012a, 3013a, and 3014a to the memory circuits 3011b, 3012b, 3013b, and 3014b. The third substrate 310 is also provided with wiring 3103 for supplying read signals for count values ​​to the memory circuits 3011b, 3012b, 3013b, and 3014b. The wirings 3101, 3102, 3103, and 3104 are second wirings for supplying a second control signal for controlling the operation of the signal processing circuit to the signal processing circuit.

[0052] The pixel 121 is provided with buffers 1215, 1216, 1217, and 1218 that adjust the timing of control signals transmitted through the wirings 3101, 3102, 3103, and 3104. Similarly, the pixel 123 is provided with buffers 1235, 1236, 1237, and 1238 that adjust the timing of control signals transmitted through the wirings 3101, 3102, 3103, and 3104. It is possible to determine which pixels the buffers 1215, 1216, 1217, 1218, 1235, 1236, 1237, and 1238 are provided in as appropriate. That is, in the third substrate 3100, each of these buffers The pitch at which the buffers are provided may be different.

[0053] According to the photoelectric conversion device 150 of this modification, the wiring 2101 for signals supplied to the MOSFETs 2011a, 2012a, 2013a, and 2014a provided on the second substrate 210 is provided on the second substrate 2100 instead of the third substrate 310. This allows a larger area to be secured on the third substrate 310 for providing wiring, elements, and the like, and allows the components of the third substrate 310 to be further miniaturized.

[0054] Second embodiment Next, a photoelectric conversion device according to a second embodiment will be described with reference to the drawings. In the following description, the same components as those in the above embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0055] Fig. 9 is a block diagram showing an example of a circuit of a photoelectric conversion device 200 according to this embodiment. Note that some components of the photoelectric conversion device 200 will be omitted in the description of Fig. 9. As shown in Fig. 9, the photoelectric conversion device 200 includes a first substrate 110, a second substrate 210, and a third substrate 310.

[0056] In the first substrate 110, pixels 221 and 222 are provided in the pixel region 12. Note that in the pixel region 12, a plurality of pixels having the same configuration as the pixels 221 and 222 are arranged two-dimensionally, but in the following, only the pixels 221 and 222 will be described, and a description of the other pixels will be omitted. The pixels 221 and 222 each include an APD 1211, 1221, a pixel control circuit 2011, 2012 connected to the APD 1211, 1221, and a signal processing circuit 3011, 3012 connected to the pixel control circuit 2011, 2012, respectively.

[0057] The peripheral region 13 of the second substrate 210 is provided with wiring 2101 that supplies a control signal (PCLK) to the pixel control circuits 2011 and 2012. The pixel region 12 of the second substrate 210 is provided with a buffer 2102 as a global buffer that adjusts the timing, such as the transmission speed, of the control signal transmitted by the wiring 2101. The pixel region 12 of the second substrate 210 is provided with a buffer 2103 as a local buffer that sends the control signal transmitted via the buffer 2102 to the pixel control circuits 2011 and 2012. The buffer 2102 is a first buffer that outputs a first control signal to a plurality of groups each consisting of two or more pixels of the plurality of pixels. The buffer 2103 is a second buffer that outputs a first control signal to each pixel included in the plurality of groups.

[0058] Furthermore, the third substrate 310 is provided with a control signal generating circuit 302 in the peripheral region 13. Furthermore, in the third substrate 310, the pixels 221 and 222 are provided with signal processing circuits 3011 and 3012. Furthermore, the third substrate 310 is provided with wirings 3101, 3102, and 3103, respectively.

[0059] In this embodiment, a buffer 3105 is provided as a global buffer that adjusts the timing of the transmission speed of signals transmitted through the wirings 3101, 3102, and 3103. The third substrate 310 is also provided with a buffer 3106 as a local buffer that supplies signals transmitted through the wirings 3101, 3102, and 3103 to the signal processing circuits 3011 and 3012.

[0060] 9, in this embodiment, buffers 2102, 2103, 3105, and 3106 are provided for each pair of pixels 221 and 222. However, which pixels each of these buffers is provided for may be determined appropriately. That is, the pitches at which each of these buffers is provided on the third substrate 310 may be different from each other.

[0061] The delay increases with the distance between the buffers 2102 and 3105 and the pixel to which the signal is supplied. For this reason, if the buffers 2102 and 3105 are used alone to adjust the timing of the signal transmission speed and other factors for each pixel in the pixel region 12, the configuration of the buffers 2102 and 3105 may become complicated. Therefore, in the photoelectric conversion device 200 of this embodiment, buffers 2102, 2103, 3105, and 3106 are provided for the pair of pixels 221 and 222. This distributes the signal processing load of the buffers 2102 and 3105, making it possible to reduce the delay of the control signal supplied to each pixel.

[0062] Moreover, according to the photoelectric conversion device 200 of this embodiment, the wiring 2101 for signals supplied to the pixel control circuits 2011, 2012 provided on the second substrate 210 is provided on the second substrate 210 instead of the third substrate 310. In this manner, when a circuit for processing signals from the APDs 1211, 1221 is provided on the second substrate 210, a circuit for supplying a control signal to the circuit is provided on the same second substrate 210, not on the third substrate 310. This allows a larger area to be secured on the third substrate 310 for providing wiring, elements, and the like, and allows further miniaturization of the components of the third substrate 310.

[0063] Third embodiment Next, a photoelectric conversion device according to a third embodiment will be described with reference to the drawings. In the following description, the same components as those in the above-described embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0064] Fig. 10 is a block diagram showing an example of a circuit of a photoelectric conversion device 300 according to this embodiment. Note that some components of the photoelectric conversion device 300 will be omitted in the description of Fig. 10. As shown in Fig. 10, the photoelectric conversion device 300 includes a first substrate 110, a second substrate 210, and a third substrate 310.

[0065] In the first substrate 110, pixels 321, 322, 323, and 324 are provided in the pixel region 12. Note that in the pixel region 12, a plurality of pixels having the same configuration as the pixels 321, 322, 323, and 324 are arranged two-dimensionally, but in the following, the pixels 321, 322, 323, and 324 will be described, and a description of the other pixels will be omitted. The pixels 321, 322, 323, and 324 include APDs 1211, 1221, 1231, and 1241, and pixel control circuits 2011, 2012, 2013, and 2014 connected to the APDs 1211, 1221, 1231, and 1241, respectively. The pixels 321, 322, 323, and 324 further include signal processing circuits 3011, 3012, 3013, and 3014 connected to pixel control circuits 2011, 2012, 2013, and 2014, respectively.

[0066] The peripheral region 13 of the second substrate 210 is provided with wiring 2101 that supplies a control signal (PCLK) to the pixel control circuits 2011, 2012, 2013, and 2014. The pixel region 12 of the second substrate 210 is provided with a buffer 2104 as a global buffer that adjusts the timing of the transmission speed of the control signal transmitted by the wiring 2101. The pixel region 12 of the second substrate 210 is provided with a buffer 2105 as a local buffer that sends the control signal transmitted through the buffer 2104 to the pixel control circuits 2011 and 2012. Similarly, the pixel region 12 of the second substrate 210 is provided with a buffer 2106 as a global buffer that adjusts the timing of the transmission speed of the control signal output from the buffer 2104. The pixel region 12 of the second substrate 210 is provided with a buffer 2107 as a local buffer that sends the control signal transmitted through the buffer 2106 to the pixel control circuits 2013 and 2014.

[0067] In this embodiment, the buffers 2104, 2105, 2106, and 2107 are buffers and interfaces. The first buffer 2104 is configured with a combinational logic circuit having a pair of a buffer and an inverter. The buffer 2107 has two pairs of a buffer and an inverter connected in series. Therefore, the buffer 2104, which is the first buffer, has a logic circuit that inverts the first control signal that is input. As a result, the pulse waveform of the control signal transmitted by the wiring 2101 is inverted by the buffers 2104 and 2105, respectively, and supplied to the pixel control circuits 2011 and 2012. The control signal output from the buffer 2104 is inverted by the buffer 2106, and further inverted twice by the buffer 2107, and supplied to the pixel control circuits 2013 and 2014.

[0068] In the photoelectric conversion device 200 of the second embodiment, the buffers 2102 and 2103 are configured with a positive logic circuit. Therefore, delays in the rising or falling edges of the pulse of the control signal transmitted through the wiring 2101 accumulate, which may cause the pulse waveform of the control signal to be distorted. On the other hand, in the photoelectric conversion device 300 of the present embodiment, in the buffers 2104 and 2106, the delays in the rising edge and the falling edge of the pulse of the control signal are switched every time the control signal is inverted. As a result, the buffers 2104 and 2106 can output the control signal without distorting the pulse waveform of the input control signal.

[0069] In the photoelectric conversion device 300, the control signal output from the control signal generation circuit 302 is inverted by the buffer 2104, and is then inverted again in the buffer 2105 before being supplied to the pixel control circuits 2011 and 2012. The control signal output from the buffer 2104 is inverted again by the buffer 2106, that is, the control signal output from the control signal generation circuit 302 is in a non-inverted state. Therefore, the control signal output from the buffer 2106 is inverted twice in the buffer 2107 before being supplied to the pixel control circuits 2011 and 2012.

[0070] The third substrate 310 has a control signal generating circuit 302 provided in the peripheral region 13. Furthermore, in the third substrate 310, the pixels 321, 322, 323, and 324 have signal processing circuits 3011, 3012, 3013, and 3014. Furthermore, the third substrate 310 has wirings 3101, 3102, and 3103 provided thereon, respectively.

[0071] In this embodiment, buffers 3107 and 3109 are provided as global buffers that adjust the timing of the transmission speeds of signals transmitted through wirings 3101, 3102, and 3103. Third substrate 310 is also provided with buffer 3108 as a local buffer that supplies signals transmitted through wirings 3101, 3102, and 3103 to signal processing circuits 3011 and 3012. Similarly, buffer 3110 is provided as a local buffer that supplies each signal output from buffer 3107 to signal processing circuits 3013 and 3014.

[0072] The inversion of each signal by the buffers 3107, 3108, 3109, and 3110 is similar to the inversion by the buffers 2104, 2105, 2106, and 2107 of the control signal transmitted by the wiring 2101 described above, and therefore a detailed description thereof will be omitted here.

[0073] 10, in this embodiment, buffers 3107 and 3108 are provided for a pair of pixels 321 and 322, and buffers 3109 and 3110 are provided for a pair of pixels 323 and 324. However, which pixels these buffers are provided for may be determined appropriately. That is, the pitches at which these buffers are provided on the second substrate 210 and the third substrate 310 may be different from each other.

[0074] According to the photoelectric conversion device 300 of this embodiment, buffers 3107 and 3108 are provided for the pair of pixels 321 and 322, and buffers 3109 and 3110 are provided for the pair of pixels 323 and 324, respectively. This makes it possible to distribute the signal processing load of the buffers 2104 and 3107 and reduce the delay in the control signals supplied to each pixel.

[0075] Moreover, according to the photoelectric conversion device 300 of this embodiment, the wiring 2101 for signals supplied to the pixel control circuits 2011, 2012, 2013, and 2014 provided on the second substrate 210 is provided on the second substrate 210 instead of the third substrate 310. In this manner, when a circuit for processing signals from the APDs 1211, 1221, 1231, and 1241 is provided on the second substrate 210, a circuit for supplying a control signal to the circuit is provided on the same second substrate 210, not on the third substrate 310. This allows a larger area to be secured on the third substrate 310 for providing wiring, elements, and the like, and allows further miniaturization of the components of the third substrate 310.

[0076] (Fourth embodiment) The photoelectric conversion system according to this embodiment will be described with reference to Fig. 11. Fig. 11 is a block diagram showing a schematic configuration of the photoelectric conversion system according to this embodiment.

[0077] The photoelectric conversion devices described in the first to third embodiments are applicable to various photoelectric conversion systems. The photoelectric conversion system includes at least the photoelectric conversion device according to the above embodiments and a signal processing unit that processes a signal output from the photoelectric conversion device. Examples of devices to which such photoelectric conversion systems can be applied include digital still cameras, digital camcorders, security cameras, copiers, fax machines, mobile phones, vehicle-mounted cameras, observation satellites, sensors, and measuring instruments. Camera modules equipped with an optical system such as a lens and an imaging device are also included in devices to which the photoelectric conversion system is applied. FIG. 11 illustrates a block diagram of a digital still camera as an example of these devices.

[0078] 11 includes an image pickup device 404 which is an example of a photoelectric conversion device, a lens 402 which forms an optical image of a subject on the image pickup device 404, an aperture 403 which varies the amount of light passing through the lens 402, and a barrier 401 which protects the lens 402. The lens 402 and the aperture 403 form an optical system which focuses light on the image pickup device 404. The image pickup device 404 is a photoelectric conversion device according to any one of the above embodiments, and converts the optical image formed by the lens 402 into an electrical signal.

[0079] The photoelectric conversion system also has a signal processing unit 407 which is an image generating unit that generates an image by processing an output signal output from the imaging device 404. The signal processing unit 407 performs various corrections and compression as necessary to output image data. The signal processing unit 407 may be formed on a semiconductor substrate on which the imaging device 404 is provided, or may be formed on a semiconductor substrate separate from the imaging device 4004. Moreover, the imaging device 404 and the signal processing unit 407 may be formed on the same semiconductor substrate.

[0080] The photoelectric conversion system further includes a memory unit 410 for temporarily storing image data, and an external interface unit (external I / F unit) 413 for communicating with an external computer or the like. The photoelectric conversion system further includes a recording medium 412 such as a semiconductor memory for recording or reading out imaging data, and a recording medium control interface unit (recording medium control I / F unit) 411 for recording or reading out data on the recording medium 412. The recording medium 412 may be built into the photoelectric conversion system, or may be removable.

[0081] The photoelectric conversion system further includes an overall control / calculation unit 409 that performs various calculations and controls the entire digital still camera, and a timing generation unit 408 that outputs various timing signals to the image pickup device 404 and the signal processing unit 407. Here, the timing signals may be input from outside, and the photoelectric conversion system includes at least the image pickup device 404 and the output signal output from the image pickup device 404. and a signal processing unit 407 for processing the force signal.

[0082] The imaging device 404 outputs an imaging signal to the signal processing unit 407. The signal processing unit 407 performs predetermined signal processing on the imaging signal output from the imaging device 404, and outputs image data. The signal processing unit 407 generates an image using the imaging signal.

[0083] In this way, according to this embodiment, it is possible to realize a photoelectric conversion system to which the photoelectric conversion device (imaging device) according to any one of the above embodiments is applied.

[0084] Fifth embodiment The photoelectric conversion system and the moving object of this embodiment will be described with reference to Fig. 12. Fig. 12 is a diagram showing the configuration of the photoelectric conversion system and the moving object of this embodiment.

[0085] FIG. 12A shows an example of a photoelectric conversion system related to an in-vehicle camera. The photoelectric conversion system 500 has an imaging device 510. The imaging device 510 is the photoelectric conversion device described in any of the above embodiments. The photoelectric conversion system 500 has an image processing unit 512 that performs image processing on a plurality of image data acquired by the imaging device 510. The photoelectric conversion system 500 also has a distance acquisition unit 516 that calculates a distance to an object, and a collision determination unit 518 that determines whether or not there is a possibility of collision based on the calculated distance. Here, the distance acquisition unit 516 may acquire distance information to the object using ToF (Time Of Flight), or may acquire distance information using parallax information or the like. That is, the distance information is information related to parallax, defocus amount, distance to the object, and the like. The collision determination unit 518 may use any of these distance information to determine the possibility of collision. The distance information acquisition means may be realized by dedicated hardware or may be realized by a software module. It may also be realized by a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like, or may be realized by a combination of these.

[0086] The photoelectric conversion system 500 is connected to a vehicle information acquisition device 520, and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. The photoelectric conversion system 500 is also connected to an ECU 530, which is a control device that outputs a control signal to generate a braking force for the vehicle based on the judgment result of the collision judgment unit 518. The photoelectric conversion system 500 is also connected to an alarm device 540 that issues an alarm to the driver based on the judgment result of the collision judgment unit 518. For example, when the judgment result of the collision judgment unit 518 indicates that there is a high possibility of a collision, the ECU 530 performs vehicle control to avoid a collision and reduce damage by applying the brakes, releasing the accelerator, suppressing engine output, etc. The alarm device 540 warns the user by sounding an alarm, displaying alarm information on the screen of a car navigation system, etc., and vibrating the seat belt or steering wheel.

[0087] In this embodiment, the surroundings of the vehicle, for example, the front or rear, are imaged by the photoelectric conversion system 500. Fig. 12B shows the photoelectric conversion system when imaging the area in front of the vehicle (imaging range 550). The vehicle information acquisition device 520 sends an instruction to the photoelectric conversion system 500 or the imaging device 510. This configuration can further improve the accuracy of distance measurement.

[0088] Although an example of control to prevent collision with other vehicles has been described above, the present invention can also be applied to control of automatic driving to follow other vehicles, and control of automatic driving to avoid going out of lanes. Furthermore, the photoelectric conversion system is not limited to vehicles such as automobiles, but can be applied to moving bodies (moving devices) such as ships, aircraft, and industrial robots. The moving body includes a driving force generating unit that generates a driving force mainly used for the movement of the moving body, and a driving force generating unit that generates a driving force mainly used for the moving body. The driving force generating unit may be an engine, a motor, or the like. The rotating body may be a tire, a wheel, a ship's screw, an aircraft's propeller, or the like. In addition, the present invention may be applied not only to moving bodies, but also to a wide range of devices that use object recognition, such as intelligent transport systems (ITS).

[0089] Sixth embodiment The photoelectric conversion system of this embodiment will be described with reference to Fig. 13. Fig. 13 is a block diagram showing an example of the configuration of a range image sensor which is the photoelectric conversion system of this embodiment.

[0090] 13, the distance image sensor 601 is configured to include an optical system 607, a photoelectric conversion device 608, an image processing circuit 604, a monitor 605, and a memory 606. The distance image sensor 601 can obtain a distance image according to the distance to the subject by receiving light (modulated light or pulsed light) that is projected from a light source device 609 toward the subject and reflected from the surface of the subject.

[0091] The optical system 607 is configured with one or more lenses, and guides image light (incident light) from a subject to a photoelectric conversion device 608, and forms an image on a light receiving surface (sensor unit) of the photoelectric conversion device 608. As the photoelectric conversion device 608, the photoelectric conversion device of each of the above-mentioned embodiments is applied, and a distance signal indicating a distance determined from a light receiving signal output from the photoelectric conversion device 608 is supplied to the image processing circuit 604.

[0092] The image processing circuit 604 performs image processing to construct a distance image based on the distance signal supplied from the photoelectric conversion device 608. The distance image (image data) obtained by this image processing is then supplied to a monitor 605 for display, or supplied to a memory 606 for storage (recording).

[0093] In the range image sensor 601 configured in this way, by applying the above-mentioned photoelectric conversion device, it is possible to obtain, for example, a more accurate range image as the pixel characteristics improve.

[0094] Seventh embodiment The photoelectric conversion system of this embodiment will be described with reference to Fig. 14. Fig. 14 is a diagram showing an example of a schematic configuration of an endoscopic surgery system which is the photoelectric conversion system of this embodiment.

[0095] 14 shows a state in which an operator (doctor) 731 is performing surgery on a patient 732 on a patient bed 733 using an endoscopic surgery system 750. As shown in the figure, the endoscopic surgery system 750 is composed of an endoscope 700, a surgical tool 710, and a cart 734 on which various devices for endoscopic surgery are mounted.

[0096] The endoscope 700 is composed of a lens barrel 701, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 732, and a camera head 702 connected to the base end of the lens barrel 701. In the illustrated example, the endoscope 700 is configured as a so-called rigid lens barrel having a rigid lens barrel 701, but the endoscope 700 may be configured as a so-called flexible lens barrel having a flexible lens barrel.

[0097] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 701. A light source device 730 is connected to the endoscope 700, and light generated by the light source device 730 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 701, and is irradiated toward an observation target in a body cavity of a patient 732 via the objective lens. may be a direct-view mirror, an oblique-view mirror, or a side-view mirror.

[0098] An optical system and a photoelectric conversion device are provided inside the camera head 702, and reflected light (observation light) from an observation target is collected by the optical system onto the photoelectric conversion device. The observation light is photoelectrically converted by the photoelectric conversion device to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to an observation image. The photoelectric conversion device described in each of the above-mentioned embodiments can be used as the photoelectric conversion device. The image signal is transmitted to a camera control unit (CCU: Camera Control Unit) 735 as RAW data.

[0099] The CCU 735 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and performs overall control of the operations of the endoscope 700 and the display device 736. Furthermore, the CCU 735 receives an image signal from the camera head 702, and performs various types of image processing on the image signal, such as development processing (demosaic processing), for displaying an image based on the image signal.

[0100] The display device 736, under the control of the CCU 735, displays an image based on an image signal that has been subjected to image processing by the CCU 735. The light source device 730 is composed of a light source such as an LED (Light Emitting Diode), and supplies the endoscope 700 with irradiation light when imaging an operation site or the like.

[0101] The input device 737 is an input interface for the endoscopic surgery system 750. A user can input various information and instructions to the endoscopic surgery system 750 via the input device 737.

[0102] The treatment tool control device 738 controls the driving of the energy treatment tool 712 for cauterizing tissue, incising, sealing blood vessels, etc. The light source device 730 that supplies irradiation light to the endoscope 700 when photographing the surgical site can be composed of a white light source composed of, for example, an LED, a laser light source, or a combination of these. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so that the light source device 730 can adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each of the RGB laser light sources by irradiating the observation target with laser light from each of the RGB laser light sources and controlling the driving of the image sensor of the camera head 702 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter to the image sensor.

[0103] Furthermore, the light source device 730 may be controlled to change the intensity of the light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 702 in synchronization with the timing of the change in the light intensity to acquire images in a time-division manner and synthesizing the images, it is possible to generate an image with a high dynamic range that is free of so-called blocked-up shadows and blown-out highlights.

[0104] Furthermore, the light source device 730 may be configured to supply light in a predetermined wavelength band corresponding to special light observation. In special light observation, for example, the wavelength dependency of light absorption in body tissue is utilized. Specifically, a predetermined tissue such as blood vessels on the mucosal surface layer is photographed with high contrast by irradiating light with a narrower band than the light (i.e., white light) irradiated during normal observation. Alternatively, in special light observation, fluorescent observation may be performed in which an image is obtained from fluorescence generated by irradiating excitation light. In fluorescent observation, excitation light is irradiated onto body tissue and the fluorescence from the body tissue is observed, or a reagent such as indocyanine green (ICG) is locally injected into the body tissue and excitation light corresponding to the fluorescent wavelength of the reagent is irradiated onto the body tissue to obtain a fluorescent image. The light source device 730 can be configured to be capable of supplying narrowband light and / or excitation light compatible with such special light observation.

[0105] Eighth embodiment The photoelectric conversion system of this embodiment will be described with reference to Figs. 15A and 15B. Fig. 15A describes glasses 800 (smart glasses) which are the photoelectric conversion system of this embodiment. The glasses 800 have a photoelectric conversion device 802. The photoelectric conversion device 802 is the photoelectric conversion device described in each of the above embodiments. A display device including a light-emitting device such as an OLED or LED may be provided on the back side of the lens 801. The photoelectric conversion device 802 may be one or more. A combination of multiple types of photoelectric conversion devices may also be used. The arrangement position of the photoelectric conversion device 802 is not limited to that of Fig. 15A.

[0106] The glasses 800 further include a control device 803. The control device 803 functions as a power source that supplies power to the photoelectric conversion device 802 and the display device. The control device 803 also controls the operations of the photoelectric conversion device 802 and the display device. The lens 801 is formed with an optical system for focusing light on the photoelectric conversion device 802.

[0107] FIG. 15B illustrates glasses 810 (smart glasses) according to one application example. The glasses 810 have a control device 812, and the control device 812 is equipped with a photoelectric conversion device corresponding to the photoelectric conversion device 802 and a display device. The lens 811 is formed with an optical system for projecting light emitted from the photoelectric conversion device in the control device 812 and the display device, and an image is projected onto the lens 811. The control device 812 functions as a power source for supplying power to the photoelectric conversion device and the display device, and controls the operation of the photoelectric conversion device and the display device. The control device may have a line of sight detection unit that detects the line of sight of the wearer. Infrared light may be used for detecting the line of sight. The infrared light emitting unit emits infrared light toward the eyeball of a user gazing at a display image. An imaging unit having a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an image of the eyeball. By having a reduction means for reducing light from the infrared light emitting unit to the display unit in a planar view, deterioration of image quality is reduced.

[0108] The gaze of the user with respect to the displayed image is detected from an image of the eyeball obtained by capturing infrared light. Any known method can be applied to gaze detection using the image of the eyeball. As an example, a gaze detection method based on a Purkinje image formed by reflection of irradiated light on the cornea can be used.

[0109] More specifically, a gaze detection process based on the pupil-corneal reflex method is performed. Using the pupil-corneal reflex method, a gaze vector that indicates the direction (rotation angle) of the eyeball is calculated based on the pupil image and the Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze. The display device of this embodiment may have a photoelectric conversion device having a light receiving element, and may control the display image of the display device based on information on the user's line of sight from the photoelectric conversion device.

[0110] Specifically, the display device determines a first field of view area to which the user gazes and a second field of view area other than the first field of view area based on the line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be received from an external control device. In the display area of ​​the display device, the display resolution of the first field of view area may be controlled to be higher than the display resolution of the second field of view area. In other words, the resolution of the second field of view area may be lower than that of the first field of view area.

[0111] The display area may include a first display area and a second display area different from the first display area, and an area having a higher priority may be determined from the first display area and the second display area based on the line-of-sight information. The first display area and the second display area may be determined by a control device of the display device. Alternatively, the resolution may be determined by an external control device. The resolution of a high priority area may be controlled to be higher than the resolution of areas other than the high priority area. In other words, the resolution of an area with a relatively low priority may be controlled to be lower.

[0112] AI (Artificial Intelligence) may be used to determine the first field of view area and the area with high priority. The AI ​​may be a model configured to estimate the angle of the line of sight and the distance to an object at the end of the line of sight from the image of the eyeball, using the image of the eyeball and the direction in which the eyeball in the image was actually looking as teacher data. The AI ​​program may be included in the display device, the photoelectric conversion device, or an external device. If included in the external device, it is transmitted to the display device via communication.

[0113] When display control is performed based on visual recognition detection, the present invention can be preferably applied to smart glasses further including a photoelectric conversion device for capturing an image of the outside world. The smart glasses can display captured outside information in real time.

[0114] Ninth embodiment The above-described photoelectric conversion device and photoelectric conversion system may be applied to electronic devices such as so-called smartphones and tablets.

[0115] 16A and 16B are diagrams showing an example of an electronic device 900 equipped with a photoelectric conversion device. Fig. 16A shows the front side of the electronic device 900, and Fig. 16B shows the rear side of the electronic device 900.

[0116] 16A, a display 910 for displaying an image is disposed in the center of the surface of the electronic device 900. Then, along the upper side of the surface of the electronic device 900, front cameras 921 and 922 using photoelectric conversion devices, an IR light source 930 for emitting infrared light, and a visible light source 940 for emitting visible light are disposed.

[0117] As shown in FIG. 16B, rear cameras 951 and 952 using photoelectric conversion devices, an IR light source 960 that emits infrared light, and a visible light source 970 that emits visible light are arranged along the upper side of the rear surface of the electronic device 900.

[0118] In the electronic device 900 configured in this manner, by applying the above-mentioned photoelectric conversion device, for example, it is possible to capture a higher quality image. Note that the photoelectric conversion device can also be applied to other electronic devices such as infrared sensors, distance measuring sensors using active infrared light sources, security cameras, and personal or biometric authentication cameras. This can improve the accuracy, performance, and the like of these electronic devices.

[0119] Tenth embodiment 17 is a block diagram of an X-ray CT apparatus in this embodiment. As described above, the semiconductor device in the above embodiment is applicable to a detector of an X-ray CT apparatus. The X-ray CT apparatus 1000 in this embodiment includes an X-ray generating unit 1010, a wedge 1011, a collimator 1012, an X-ray detecting unit 1020, a top plate 1030, and a rotating frame 1040. The X-ray CT apparatus 1000 further includes a high voltage generating device 1050, a data acquisition system (DAS) 1051, a signal processing unit 1052, a display unit 1053, and a control unit 1054.

[0120] The X-ray generating unit 1010 is composed of, for example, a vacuum tube that generates X-rays. A high voltage and a filament current are supplied from a high voltage generator 1050 to the vacuum tube of the X-ray generating unit 1010. Thermal electrons are irradiated from the cathode (filament) toward the anode (target). This produces X-rays.

[0121] The wedge 1011 is a filter that adjusts the amount of X-rays irradiated from the X-ray generating unit 1010. The wedge 1011 attenuates the amount of X-rays so that the X-rays irradiated from the X-ray generating unit 1010 to the subject have a predetermined distribution. The collimator 1012 is made of a lead plate or the like that narrows down the irradiation range of the X-rays that have passed through the wedge 1011. The X-rays generated by the X-ray generating unit 1010 are shaped into a cone beam via the collimator 1012 and irradiated to the subject on the tabletop 1030.

[0122] The X-ray detection unit 1020 is configured using the semiconductor device according to the above-mentioned embodiment. The X-ray detection unit 1020 detects X-rays emitted from the X-ray generation unit 1010 and transmitted through the subject, and outputs a signal corresponding to the X-ray dose to the DAS 1051.

[0123] The rotating frame 1040 has an annular shape and is configured to be rotatable. An X-ray generation unit 1010 (wedge 1011, collimator 1012) and an X-ray detection unit 1020 are arranged facing each other inside the rotating frame 1040. The X-ray generation unit 1010 and the X-ray detection unit 1020 are rotatable together with the rotating frame 1040.

[0124] The high-voltage generator 1050 includes a boost circuit, and outputs a high voltage to the X-ray generation unit 1010. The DAS 1051 includes an amplifier circuit and an A / D conversion circuit, and outputs a signal from the X-ray detection unit 1020 to the signal processing unit 1052 as digital data.

[0125] The signal processing unit 1052 includes a CPU, a ROM, and a RAM, and can execute image processing on digital data. The display unit 1053 includes a flat display device, and can display X-ray images. The control unit 1054 includes a CPU, a ROM, a RAM, and controls the operation of the entire X-ray CT apparatus 1000.

[0126] Eleventh embodiment A photoelectric conversion system according to an eleventh embodiment will be described with reference to Fig. 18. Fig. 18 is a block diagram showing a schematic configuration of an imaging system SYS, which is a photoelectric conversion system according to the eleventh embodiment. The imaging system SYS includes at least a photoelectric conversion device according to the above embodiment, and a signal processing unit that processes a signal output from the photoelectric conversion device.

[0127] The imaging system SYS is an information terminal having a camera and a photographing function. The imaging system SYS is constructed using an imaging device IS. The imaging device IS may further include a package PKG that houses an imaging device IC. The package PKG may include a base to which the imaging device IC is fixed, and a lid that faces the imaging device IC. The package PKG may include a connection member (a member that connects a terminal provided on the base with a terminal provided on the imaging device IC). The imaging device IS may also mount a plurality of imaging device ICs side by side in a common package PKG. Also, the imaging device IS may also mount an imaging device IC and other semiconductor device ICs stacked on top of each other in a common package PKG.

[0128] The imaging system SYS may include an optical system OU (optical device) that forms an image on the imaging device IS. The imaging system SYS may also include at least one of a control device CU, a processing device PU, a display device DU, and a storage device MU. The control device CU controls the imaging device IS, the processing device PU processes signals from the imaging device IS, the display device DU displays images obtained from the imaging device IS, and the storage device MU stores images obtained from the imaging device IS.

[0129] <Other> In the above embodiment, various devices have been described, but the camera may further include a mechanical device. The mechanical device in the camera can drive optical components for zooming, focusing, and shutter operation, or the mechanical device in the camera can move a photoelectric conversion device for vibration reduction operation.

[0130] The device may be transportation equipment such as a vehicle, ship, or aircraft. A mechanical device in a transportation device may be used as a moving device. The device as a transportation device is suitable for transporting a photoelectric conversion device or for assisting and / or automating driving (piloting) by using an imaging function. A processing device for assisting and / or automating driving (piloting) may perform processing for operating the mechanical device as a moving device based on information obtained by the photoelectric conversion device.

[0131] In the present specification, expressions such as "A or B", "at least one of A and B", "at least one of A and / or B", "one or more of A and / or B" may be used. In this case, unless otherwise expressly defined, all possible combinations of the listed items can be included. That is, the above expressions are understood to disclose all cases including at least one A, at least one B, and both at least one A and at least one B. This also applies to combinations of three or more elements.

[0132] The above-described embodiments can be modified as appropriate without departing from the technical concept. The disclosure of this specification includes not only what is described in this specification, but also all matters that can be understood from this specification and the drawings attached hereto. The disclosure of this specification also includes the complement of the concepts described in this specification. In other words, if this specification contains a statement that "A is greater than B," for example, this specification can be said to disclose that "A is not greater than B" even if the statement that "A is not greater than B" is omitted. This is because when it is stated that "A is greater than B," it is assumed that the case in which "A is not greater than B" is taken into consideration.

[0133] The disclosure of this embodiment includes the following configuration. (Configuration 1) a pixel including an avalanche photodiode, a pixel circuit for performing processing using a signal output from the avalanche photodiode, and a signal processing circuit for performing processing using the signal output from the pixel circuit; a control signal generating circuit that generates a first control signal for controlling an operation of the pixel circuit and a second control signal for controlling an operation of the signal processing circuit; Equipped with a second circuit layer in which the signal processing circuit and the control signal generating circuit are arranged, a first circuit layer in which the pixel circuits are arranged, and a photodiode layer in which the avalanche photodiodes are arranged are laminated in this order; an output terminal of the avalanche photodiode is connected to the pixel circuit; A plurality of the pixels are arranged in a pixel region, the control signal generating circuit is disposed in a peripheral region provided around the pixel region, A first wiring that supplies the first control signal to the pixel circuit is provided in the first circuit layer, and the first wiring is connected to the control signal generating circuit in the peripheral region. A photoelectric conversion device comprising: (Configuration 2) 2. The photoelectric conversion device according to claim 1, wherein in the pixel region, buffers are arranged in the first wiring at a constant pitch corresponding to a pixel unit. (Configuration 3) The plurality of pixels include at least one pixel in which a buffer is not provided on the first wiring and at least one pixel in which a buffer is provided on the first wiring. 3. The photoelectric conversion device according to configuration 1 or 2. (Configuration 4) 4. The photoelectric conversion device according to any one of configurations 1 to 3, wherein in the pixel region, the first wiring is provided in the first circuit layer. (Configuration 5) 5. The photoelectric conversion device according to any one of configurations 1 to 4, wherein in the pixel region, a second wiring for supplying the second control signal to the signal processing circuit is provided in the second circuit layer. (Configuration 6) 6. The photoelectric conversion device according to any one of configurations 1 to 5, wherein the elements arranged on the first circuit layer have a higher withstand voltage than the elements arranged on the second circuit layer. (Configuration 7) the pixel circuit includes a control circuit for the avalanche photodiode; The signal processing circuit includes a count circuit that performs count processing of the signal output from the pixel circuit. 7. The photoelectric conversion device according to any one of configurations 1 to 6. (Configuration 8) The photoelectric conversion device according to any one of configurations 1 to 7, wherein the pixel circuit includes a quench element that performs a quenching operation on the avalanche photodiode and a waveform shaping circuit that performs a waveform shaping process on a signal output from the avalanche photodiode. (Configuration 9) 9. The photoelectric conversion device according to configuration 8, wherein the quench element is controlled by the first control signal to be in a high resistance state or a low resistance state having a resistance value lower than that of the high resistance state. (Configuration 10) 8. The photoelectric conversion device according to configuration 7, wherein the count circuit has a flip-flop that performs the counting process, and a memory that holds a count value obtained by the counting process. (Configuration 11) A photoelectric conversion device according to any one of configurations 1 to 10, characterized in that the first wiring is provided with a first buffer that outputs the first control signal to a plurality of groups each consisting of two or more pixels of the plurality of pixels, and a second buffer that outputs the first control signal to each pixel included in the plurality of groups. (Configuration 12) 12. The photoelectric conversion device according to configuration 11, wherein the first buffer has a logic circuit that inverts the first control signal input thereto. (Configuration 13) A photoelectric conversion device according to any one of configurations 1 to 12, and a signal processing unit that generates an image using a signal output from the photoelectric conversion device. (Configuration 14) A moving object including the photoelectric conversion device according to any one of configurations 1 to 12, A moving body comprising: a control unit that controls the movement of the moving body using a signal output from the photoelectric conversion device. (Configuration 15) An apparatus including the photoelectric conversion device according to any one of configurations 1 to 12, an optical device corresponding to the photoelectric conversion device; A control device for controlling the photoelectric conversion device; a processing device that processes a signal output from the photoelectric conversion device; a display device that displays information obtained by the photoelectric conversion device; a storage device that stores information obtained by the photoelectric conversion device; and and a mechanical device that operates based on information obtained by the photoelectric conversion device. [Explanation of symbols]

[0134] 12 pixel region, 13 peripheral region, 100 photoelectric conversion device, 110 first substrate, 210 second substrate, 310 third substrate, 121 pixel, 302 control signal generating circuit, 1211 APD, 2011 pixel control circuit, 2101 wiring, 3011 signal processing circuit

Claims

1. a pixel including an avalanche photodiode, a pixel circuit for performing processing using a signal output from the avalanche photodiode, and a signal processing circuit for performing processing using the signal output from the pixel circuit; a control signal generating circuit that generates a first control signal for controlling an operation of the pixel circuit and a second control signal for controlling an operation of the signal processing circuit; Equipped with a second circuit layer in which the signal processing circuit and the control signal generating circuit are arranged, a first circuit layer in which the pixel circuits are arranged, and a photodiode layer in which the avalanche photodiodes are arranged, stacked in this order; an output terminal of the avalanche photodiode is connected to the pixel circuit; A plurality of the pixels are arranged in a pixel region, the control signal generating circuit is disposed in a peripheral region provided around the pixel region, A first wiring that supplies the first control signal to the pixel circuit is provided in the first circuit layer, and the first wiring is connected to the control signal generating circuit in the peripheral region. A photoelectric conversion device comprising:

2. 2 . The photoelectric conversion device according to claim 1 , wherein in the pixel region, buffers are arranged in the first wiring at a constant pitch corresponding to a pixel unit.

3. 2. The photoelectric conversion device according to claim 1, wherein the plurality of pixels include at least one pixel in which a buffer is not provided on the first wiring and at least one pixel in which a buffer is provided on the first wiring.

4. The photoelectric conversion device according to claim 1 , wherein the first wiring is provided in the first circuit layer in the pixel region.

5. 2 . The photoelectric conversion device according to claim 1 , wherein a second wiring for supplying the second control signal to the signal processing circuit is provided in the second circuit layer in the pixel region.

6. 2. The photoelectric conversion device according to claim 1, wherein the elements arranged on the first circuit layer have a higher withstand voltage than the elements arranged on the second circuit layer.

7. the pixel circuit includes a control circuit for the avalanche photodiode; The signal processing circuit includes a count circuit that performs count processing of the signal output from the pixel circuit.

2. The photoelectric conversion device according to claim 1.

8. 2. The photoelectric conversion device according to claim 1, wherein the pixel circuit includes a quench element that performs a quenching operation on the avalanche photodiode, and a waveform shaping circuit that performs a waveform shaping process on the signal output from the avalanche photodiode.

9. 9. The photoelectric conversion device according to claim 8, wherein the quench element is controlled by the first control signal to be in a high resistance state or a low resistance state having a resistance value lower than that of the high resistance state.

10. 8. The photoelectric conversion device according to claim 7, wherein the count circuit includes a flip-flop that performs the counting process, and a memory that holds the count value obtained by the counting process.

11. The photoelectric conversion device according to claim 1, characterized in that the first wiring is provided with a first buffer that outputs the first control signal to multiple groups of two or more pixels of the plurality of pixels, and a second buffer that outputs the first control signal to each pixel included in the multiple groups.

12. 12. The photoelectric conversion device according to claim 11, wherein the first buffer includes a logic circuit that inverts the first control signal input thereto.

13. The photoelectric conversion device according to any one of claims 1 to 12, and a signal processing unit that generates an image using a signal output from the photoelectric conversion device.

14. A moving object comprising the photoelectric conversion device according to any one of claims 1 to 12, A moving body comprising: a control unit that controls the movement of the moving body using a signal output from the photoelectric conversion device.

15. An apparatus comprising the photoelectric conversion device according to any one of claims 1 to 12, an optical device corresponding to the photoelectric conversion device; A control device for controlling the photoelectric conversion device; a processing device that processes a signal output from the photoelectric conversion device; a display device that displays information obtained by the photoelectric conversion device; a storage device that stores information obtained by the photoelectric conversion device; and and a mechanical device that operates based on information obtained by the photoelectric conversion device.

Images