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JP-2026074710-A - Photodetector and electronic equipment

JP2026074710AJP 2026074710 AJP2026074710 AJP 2026074710AJP-2026074710-A

Abstract

[Problem] To provide an optical detection device and electronic equipment that reduces the number of wiring layers by appropriately arranging circuits and wiring in the light receiving chip and detection chip, and also reduces costs. [Solution] The light detection device comprises a first chip including a light receiving unit that converts incident light into an electrical signal, a part of a conversion circuit that converts the electrical signal into a voltage signal, a first buffer circuit that outputs a first detection signal corresponding to the voltage signal, and first and second capacitive elements with one end connected to the output of the first buffer circuit; and a second chip including a first comparator connected to the other end of the first capacitive element that outputs a first output signal when the first or second detection signal exceeds a first threshold voltage higher than the first or second detection signal, and a second comparator connected to the other end of the second capacitive element that outputs a second output signal when the first or second detection signal falls below a second threshold voltage lower than the first or second detection signal, with the first chip and the second chip stacked. [Selection Diagram] Figure 8

Inventors

  • 北野 伸

Assignees

  • ソニーセミコンダクタソリューションズ株式会社

Dates

Publication Date
20260507
Application Date
20241021

Claims (14)

  1. A first chip comprising: a light receiving unit that converts incident light into an electrical signal; a part of a conversion circuit that converts the electrical signal into a voltage signal; a first buffer circuit that outputs a first detection signal corresponding to the voltage signal; and first and second capacitive elements, one end of which is connected to the output of the first buffer circuit; and The second chip includes a first comparator connected to the other end of the first capacitive element, which outputs a first output signal when the first detection signal exceeds a first threshold voltage, and a second comparator connected to the other end of the second capacitive element, which outputs a second output signal when the first detection signal falls below a second threshold voltage that is lower than the first threshold voltage. A light detection device in which the first chip and the second chip are stacked.
  2. The first capacitive element is provided between the output of the first buffer circuit and one of the input terminals of the first comparator. The second capacitive element is provided between the output of the first buffer circuit and one of the input terminals of the second comparator. The first threshold voltage is applied to the other input terminal of the first comparator. The photodetector according to claim 1, wherein the second threshold voltage is applied to the other input terminal of the second comparator.
  3. A first junction is provided between the other end of the first capacitive element and one input terminal of the first comparator, The photodetector according to claim 1, further comprising a second junction provided between the other end of the second capacitive element and one input terminal of the second comparator.
  4. The photodetector according to claim 3, wherein the first and second joints are joints formed by directly joining the wiring of the first chip and the wiring of the second chip.
  5. The power supply portion of the conversion circuit is provided on the second chip, as described in claim 1.
  6. The photodetector according to claim 1, further comprising a quantizer that binarizes the first and second output signals, on the second chip.
  7. The first chip includes an N-type transistor and does not have a P-type transistor, as described in claim 1.
  8. The photodetector according to claim 1, wherein the second chip has a CMOS (Complementary Metal Oxide Semiconductor).
  9. The first chip has an analog circuit configured using the first transistor, The photodetector according to claim 1, wherein the second chip has a digital circuit configured using a second transistor having a lower breakdown voltage than the first transistor.
  10. The power supply portion of the first buffer circuit is shared with the power supply portion of the conversion circuit and is provided on the second chip, as described in claim 5.
  11. A third junction electrically connects the power supply portion of the conversion circuit and the power supply of the first chip for each pixel of the light receiving section, The light detection device according to claim 10, further comprising a fourth junction that electrically connects the power supply portion of the first buffer circuit and the power supply of the first chip to each pixel of the light receiving unit.
  12. The power supply portion of the first buffer circuit and the power supply portion of the conversion circuit are shared and provided on the first chip, as described in claim 1.
  13. The first chip has an analog circuit, The light detection device according to claim 12, wherein the second chip has a digital circuit.
  14. A first chip comprising: a light receiving unit that converts incident light into an electrical signal; a part of a conversion circuit that converts the electrical signal into a voltage signal; a first buffer circuit that outputs a first detection signal corresponding to the voltage signal; and first and second capacitive elements, one end of which is connected to the output of the first buffer circuit; and The second chip includes a first comparator connected to the other end of the first capacitive element, which outputs a first output signal when the first detection signal exceeds a first threshold voltage, and a second comparator connected to the other end of the second capacitive element, which outputs a second output signal when the first detection signal falls below a second threshold voltage that is lower than the first threshold voltage. An electronic device having a light detection device, wherein the first chip and the second chip are stacked.

Description

This disclosure relates to a photodetector and electronic equipment. A light detection device has been developed that can detect event signals in real time when the light intensity of a pixel exceeds a threshold. Such a light detection device that detects event signals is called an EVS (Event Vision Sensor). An EVS is a sensor that detects changes in pixel brightness and outputs the changed data combined with coordinate and time information. Patent No. 7141440 A block diagram showing one example configuration of a light detection device according to the first embodiment.A figure showing an example of a stacked structure of a solid-state image sensor according to the first embodiment.An example of a plan view of a light-receiving chip.An example of a plan view of the pixel array section.An example of a plan view of a detection chip.An example of a plan view of the detection unit.A block diagram showing an example of the configuration of an event detection circuit.A circuit diagram showing an example of the configuration of an event detection circuit.A schematic cross-sectional view showing an example of the configuration of a light detection device according to the first embodiment.A schematic cross-sectional view showing a photodetector according to a comparative example.A diagram showing an example of the configuration of an event detection circuit according to the second embodiment.A schematic perspective view showing an example configuration of a photodetector when the buffer's power line is located on the light-receiving chip side.A schematic perspective view showing an example of the power supply connection configuration for a transistor in a logarithmic transformation circuit.A diagram showing an example of the configuration of an event detection circuit according to the third embodiment.A diagram showing another example of a buffer configuration according to the fourth embodiment.A block diagram showing an example of a general configuration of a vehicle control system.An explanatory diagram showing an example of the installation location of the external information detection unit and the imaging unit. The following describes specific embodiments of this technology in detail with reference to the drawings. The drawings are schematic or conceptual, and the proportions of each part may not necessarily be identical to those of actual objects. In the specification and drawings, elements similar to those described above are denoted by the same reference numerals, and detailed explanations are omitted where appropriate. (First Embodiment) Figure 1 is a block diagram showing an example configuration of a light detection device 1 according to the first embodiment. The light detection device 1 is, for example, an EVS or DVS (Dynamic Vision Sensor). The light detection device 1 comprises an imaging lens 10, a solid-state image sensor 20, a recording area 30, and a control unit 40. Examples of the light detection device 1 include electronic devices such as cameras mounted on industrial robots, in-vehicle cameras, and surveillance cameras. The imaging lens 10 focuses the incident light and guides it to the solid-state image sensor 20. The solid-state image sensor 20 converts the incident light into photoelectric energy to generate a voltage signal corresponding to the amount of light received, and detects changes in the amount of light received as an event signal based on the change in the voltage signal. The detected event signal is output to the recording area 30. The recording area 30 records event signals from the solid-state image sensor 20. The recording area 30 may be, for example, a latch circuit, DRAM (Dynamic Random Access Memory), flash memory, or other semiconductor memory. The internal configuration of the recording area 30 will be explained in more detail later. The control unit 40 is configured with a microcomputer, for example, equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM, etc. The CPU controls the operation of the light detection device 1 by executing processing according to a program. In particular, the control unit 40 controls the solid-state image sensor 20 to perform the event signal detection operation described above, controls the recording area 30 to record the event signal, and performs processing to read the event signal from the recording area 30. Figure 2 shows an example of a stacked structure of a solid-state image sensor 20 according to the first embodiment. The solid-state image sensor 20 comprises a detection chip 202 and a light-receiving chip 201 stacked on the detection chip 202. In such a stacked structure, the light-receiving chip 201 and the detection chip 202 are electrically connected via connection points such as vias. In addition to vias, connections can also be made using Cu-Cu junctions or bumps. Figure 3 is an example of a plan view of the light-receiving chip 201. The light-receiving chip 201 includes a pixel array section 220 and via ar