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SonyGranted patentCameras & imagingInterest 4/10

Sony patents circuit for precise distance measurement using light sensors

Sony describes a photodetection circuit that uses an avalanche photodiode to detect light for measuring distance. It includes a comparison circuit that checks the signal against a reference voltage, which is adjusted by a state detecting circuit to improve accuracy.

Why it mattersThis design helps electronic devices measure how far away objects are more reliably, which is useful for features like camera autofocus or obstacle detection.

In the filing’s own words

There is provided a photodetection circuit and a distance measuring device. The photodetection circuit includes an avalanche photodiode, a charging circuit that supplies a voltage to the avalanche photodiode, and an input amplifier including a comparison circuit in which a voltage level of an output terminal changes according to a comparison result between a voltage of an input terminal connected to the avalanche photodiode and a reference voltage, and a voltage control circuit that changes a potential of the reference voltage. The photodetection circuit additionally includes a state detecting circuit that sets timing for causing the voltage control circuit to change the potential of the reference voltage on the basis of a detection result of the voltage level.

What exactly they claim (claim 1)

1. A photodetection circuit, comprising: an avalanche photodiode; a charging circuit configured to supply a voltage to the avalanche photodiode; an input amplifier including: a comparison circuit configured to change a voltage level of an output terminal of the input amplifier based on a comparison result between a voltage of an input terminal of the input amplifier and a reference voltage, and a voltage control circuit configured to change a potential of the reference voltage, wherein the input terminal of the input amplifier is connected to the avalanche photodiode, the comparison circuit includes an inverter circuit, and the voltage control circuit includes: a switching element connected to the inverter circuit, and one of a resistive element or a current source connected in parallel with the switching element; and a state detecting circuit configured to set, based on a detection result of the voltage level, a timing for the voltage control circuit, wherein the change of the potential of the reference voltage is based on the set timing, and the switching element is configured to execute a switching operation based on an output voltage of the state detecting circuit.

Facts

Company
Sony (SONY SEMICONDUCTOR SOLUTIONS CORPORATION)
Official title
Photodetection circuit and distance measuring device
Patent number
US12733292B2
Application number
18000809
Filed
May 14, 2021
Granted
Sep 8, 2026
Inventors
1
Claims
13

Classified under

H10F 77/959 Electricity & electronicsG01J 1/44 Physics & computingH10F 30/225 Electricity & electronicsG01J 2001/4466 Physics & computingG01S 17/08 Physics & computing
Read the full filing (official PDF) ↗ Open in the Patent Tracker

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Summaries are simplified from the filing’s own abstract and first claim. A patent filing is not a product announcement.
Patent data and drawings: U.S. Patent and Trademark Office (USPTO). Nebula is not affiliated with or endorsed by the USPTO.