TOF image sensor pixel structure and ranging system

Abstract

The invention relates to a TOF image sensor pixel structure and a ranging system. The TOF image sensor pixel structure comprises an optical sensor, a first reading control unit, a second reading control unit and an anti-overflow transistor, wherein the first reading control unit, the second reading control unit and the anti-overflow transistor are respectively coupled with the optical sensor; the first reading control unit and the second reading control unit respectively comprise a reset transistor, a transmission transistor and an output unit; the reset transistor is used for resetting the voltage of the floating diffusion node; the pass transistor couples the light sensor to the corresponding floating diffusion node. The output units are coupled to the corresponding floating diffusion nodes; the first path end of the anti-overflow transistor is coupled to the voltage source, and the second path end of the anti-overflow transistor is coupled to the light sensor. The pixel structure can eliminate the background light signal when the modulated light is not opened, prevents background light charges from being transmitted to the floating diffusion node, improves the distance measurement precision, and has the characteristic of high dynamic range.

Description

technical field [0001] The invention relates to the technical field of image sensors, in particular to a TOF image sensor pixel structure and distance measuring system. Background technique [0002] Image sensors are an important part of digital cameras. According to different components, image sensors can be divided into CCD (Charge Coupled Device, Charge Coupled Device) image sensors and CMOS (Complementary Metal Oxide Semiconductor, Complementary Metal Oxide Semiconductor) image sensors. kind. However, due to the advantages of power consumption, low cost, and easy standardized production, CMOS image sensors have been widely used in various fields. [0003] With the rapid development of three-dimensional imaging information technology, especially the application of building measurement, indoor positioning and navigation, stereoscopic image and assisted living environment, there is an urgent demand for Time-of-Flight (TOF) imaging, which is applied to time-of-flight imagin...

AI Technical Summary

Problems solved by technology

[0004] In the TOF image sensor pixel, the charge generated by the background light is not helpful for measuring the distance information, but will be transmitted to the floating diffusion node in the TOF image sensor pixel due to the background light charge, thereby affecting the distance measurement accuracy.

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