Image sensor active pixel and image sensor with variable conversion gain

Abstract

The invention discloses an imaging sensor active pixel and an imaging sensor with variable conversion gain and belongs to the field of the imaging sensor. The active pixel comprises a photosensitive element which is arranged in a semiconductor base body, a charge transfer transistor which connected with the photosensitive element, a reset transistor, a source following transistor, a row choosing transistor, a transistor capacitor and a floating active area, wherein a source drain electrode of the transistor capacitor is connected with the floating active area, and a grid electrode of the transistor capacitor is connected with an external input voltage. In a low luminous environment, a gate-oxide layer capacitor portion of the transistor capacitor is not in line with a capacitor of the floating active area. In a high luminous environment, a great quantity of photoelectricity charges enable potential of the floating active area to be reduced, so that the gate-oxide layer capacitor portion of the transistor capacitor is enabled to be in line with the capacitor of the floating active area. Therefore, the active pixel effectively delays saturated time of the imaging sensor in the high luminous environment, and the sensor collects more real object detail information in the high luminous environment.

Description

technical field [0001] The invention relates to the field of image sensors, in particular to an image sensor active pixel with variable conversion gain and the image sensor. Background technique [0002] Image sensors have been widely used in digital cameras, mobile phones, medical devices, automobiles and other applications. In particular, the rapid development of CMOS (Complementary Metal Oxide Semiconductor) image sensor technology has made people have higher requirements for the output image quality of image sensors. [0003] In the prior art, a CMOS image sensor generally adopts a pixel structure with a linear photoelectric response function. like figure 1 As shown, it is an active pixel using four transistors of a CMOS image sensor, which is also called a 4T active pixel in the field. The components of a 4T active pixel include: a photodiode 101, a charge transfer transistor 102, a reset transistor 103, a source follower transistor 104, a row selection transistor 10...

AI Technical Summary

Problems solved by technology

In the outdoor environment, the linear sensor is not easy to collect the physical information of the high lighting environment, thus reducing the output image quality of the sensor

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