Pixel unit and image sensor with high dynamic range

Abstract

The invention provides a pixel unit with a high dynamic range. The pixel unit is provided with a 4T structure; a reset transistor grid part of the pixel unit and a photodiode region are overlapped to form a first charge storage grid; and a row strobe transistor grid part and the photodiode region are overlapped to form a second charge storage grid. The invention also provides an image sensor with a high dynamic range. According to the pixel unit disclosed by the invention, the reset transistor grid part and the photodiode region are overlapped to form the first charge storage grid; the row strobe transistor grid part and the photodiode region are overlapped to form a second charge storage grid; and the first charge storage grid is controlled by using a reset signal and the second charge storage grid is controlled by using a row selection signal. The capability of a storage charge of the pixel unit is enhanced and the dynamic range of the pixel unit is widened; meanwhile, the difficulty of metal wire distribution is also reduced, the packing ratio of the pixel unit is increased and the chip area of the pixel unit is reduced.

Description

Technical field [0001] The invention belongs to the field of CMOS (Complementary Metal Oxide Semiconductor) image sensors, and particularly relates to a high dynamic range pixel unit and image sensor. Background technique [0002] In recent years, the CMOS image sensor industry has developed rapidly, and image sensor manufacturers have introduced products with superior performance and smaller chip area. This puts forward higher requirements on the pixel unit, requiring image sensors to achieve high dynamic range, high sensitivity, and low noise characteristics under small pixels. However, small pixels significantly restrict the high dynamic technical indicators of the image sensor. Therefore, the use of large-size pixels in the image sensor with high dynamic range makes it difficult to improve the cost performance of the chip. [0003] Existing image sensor circuits all have one pixel array unit, which is composed of multiple pixel units. Generally, a CMOS active pixel unit conta...

AI Technical Summary

Problems solved by technology

[0009] The present invention solves the technical problems of the existing high dynamic range image sensor pixel unit layout difficulty and large chip area, and provides a pixel unit and an image sensor that do not need to add additional MOS capacitance control signals to improve the dynamic range.

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