Pixel circuits, image sensors, camera modules and electronic equipment

Abstract

Embodiments of the present application provide a pixel circuit, an image sensor, a camera module and an electronic device, which belong to the technical field of image processing. Wherein, the pixel circuit includes: a photoelectric conversion device, a charge storage, a first transfer transistor, a second transfer transistor, and an exposure control signal storage. Therefore, only one exposure control signal memory is needed, and the first transfer transistor and the second transfer transistor are controlled by continuously changing and updating the exposure control signal of each pixel within the exposure time of one frame, so that the effective exposure of each pixel can be effectively exposed. The timing is programmed by a pre-programmed exposure control signal, enabling pixel-by-pixel HDR modulation of the image sensor. On the one hand, the volume and power consumption problems of Off‑Chip technology are avoided. On the other hand, while simplifying the pixel circuit structure, the volume of the pixel can be effectively reduced, which is beneficial to the miniaturization of the pixel and improves the performance of the pixel.

Description

technical field [0001] The present application relates to the technical field of image processing, and in particular, to a pixel circuit, an image sensor, a camera module and an electronic device. Background technique [0002] In a complementary metal-oxide-semiconductor (CMOS) image sensor, the dynamic range is generally adjusted for gain by changing all pixel exposure times and pixel signals. In the High Dynamic Range (HDR) or Wide Dynamic Range (Wide Dynamic Range, WDR) technology, whether it is a multi-frame, line interleaving, or dual gain scheme, all pixels use the same exposure time. The modulation effect of HDR is 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 local overexposure or underexposure of some pixels in some scenes. [0003] In the related art, through the pixel-wise (Pixel-Wise or Per-Pixel) exposure time control t...

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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