Active pixel, high-dynamic range image sensor and method for operating active pixel

Abstract

The invention provides an active pixel, a high-dynamic range image sensor and a method for operating the active pixel. The corresponding active pixel comprises a second transmission transistor, a second reset transistor and an auxiliary capacitor, wherein the second transmission transistor is arranged between a light sensing element and a second floating node; and the second reset transistor and the auxiliary capacitor are connected to the second floating node. The corresponding method for operating the active pixel comprises the following steps of cleaning charges in a potential well of the light sensing element and controlling the light sensing element to start exposure; starting a first reset transistor and a row selection transistor to reset a first floating node, and after reset operation, stopping the first reset transistor and reading a reset signal; starting a first transmission transistor, and transferring photoelectric charges in the light sensing element into the first floating node, so as to finish the exposure of the light sensing element; stopping the first transmission transistor and reading a photoelectric signal; and stopping the row selection transistor to finish the operation of reading the photo electric signal. The dynamic range and the output image quality of the image sensor are improved.

Description

technical field [0001] The invention relates to an active pixel, a high dynamic range image sensor and a method for operating the active pixel, belonging to the technical field of image sensing. Background technique [0002] Image sensors have been widely used in digital cameras, mobile phones, medical equipment, automobiles and other occasions. In particular, the rapid development of technology for manufacturing CMOS (Complementary Metal Oxide Semiconductor, Complementary Metal Oxide Semiconductor) image sensors has made people have higher requirements for the output image quality of image sensors. [0003] In the prior art, CMOS image sensors generally adopt such as figure 1 The structure shown uses four-transistor active pixels of a CMOS image sensor, also known as 4T active pixels in the art. The components of a 4T active pixel include: a photodiode 101 , a transfer transistor 102 , a reset transistor 103 , a source follower transistor 104 and a row selection transisto...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem existing in the existing linear image sensor technology that it is impossible to collect all the signals from the dark light environment to the strong light environment, which leads to the low quality of the output image of the sensor, it further provides an active sensor. Pixel, high dynamic range image sensor, and method of operating active pixels

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