Pixel circuit, image sensor, camera module and electronic equipment

Abstract

The embodiment of the invention provides a pixel circuit, an image sensor, a camera module and electronic equipment, and belongs to the technical field of image processing. The pixel circuit comprises a photoelectric conversion device, a charge memory, a first transmission transistor, a second transmission transistor and an exposure control signal memory. Therefore, only one exposure control signal memory is needed, the first transmission transistor and the second transmission transistor are controlled by continuously changing and updating the exposure control signal of each pixel within the exposure time of one frame, the effective exposure time of each pixel can be arranged by the pre-compiled exposure control signal, and a pixel-by-pixel HDR modulation function of the image sensor is realized. On one hand, the problems of size and power consumption in the OffChip technology are avoided; and on the other hand, the size of the pixel can be effectively reduced while the structure of the pixel circuit is simplified, miniaturization of the pixel is facilitated, and the performance of the pixel is improved.

Description

technical field [0001] The present application relates to the technical field of image processing, in particular, to a pixel circuit, an image sensor, a camera module and electronic equipment. Background technique [0002] In a complementary metal-oxide semiconductor image sensor (Complemerntary metal-oxide semiconductor, CMOS), the dynamic range is generally adjusted by changing the exposure time and pixel signal of all pixels for gain adjustment. In high dynamic range (High Dynamic Range, HDR) or wide dynamic range (Wide Dynamic Range, WDR) technology, whether it is multi-frame, line interleaving, or dual gain schemes, all pixels use the same exposure time. The modulation effect of HDR can be changed by the length of exposure time and the adjustment of output signal gain. Since the exposure time of each pixel in the existing HDR technology is the same, the use of HDR results in partial overexposure or underexposure of some pixels in some scenes. [0003] In the related a...

AI Technical Summary

Problems solved by technology

However, when using Off-Chip (non-chip) technology to practice the pixel-by-pixel HDR modulation method, it is necessary to adopt a complex optical coding exposure control system. This system is not only bulky, but also requires precise calibration between different devices, which consumes high power Suitable for practical use on mobile devices such as mobile phones

When using On-Chip (on-chip) technology to practice the pixel-by-pixel HDR modulation method, the pixel circuit needs to have two or more exposure control signal storage units to control two or more charge storage units, which is not conducive to pixel Miniaturization will reduce the performance of the pixel, such as the fill factor of the pixel (Fill Factor). At the same time, using multiple exposure control signal storage units will have a certain probability that the output exposure control signals are all the same, such as all output high-level signals, Cause the charge generated by the photoelectric conversion device to flow to multiple charge storage regions at the same time and finally make the code exposure fail

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