High dynamic image sensor, pixel unit and electronic information device

Abstract

The embodiment of the invention discloses a high dynamic range image sensor, a pixel unit and an electronic information device. The image sensor comprises a reset transistor; a source follower transistor; an overflow drain; a first photodiode; a first transfer transistor; a first floating diffusion region; a second photodiode; a second transfer transistor; a second floating diffusion region; the first photodiode and the second photodiode have different full well capacities; the first photodiode and the second photodiode share one overflow drain electrode; and the source electrode of the source following transistor outputs a signal. Different from the existing 4T pixel structure design, the embodiment of the invention adopts the 3T pixel structure design and the photodiodes with different full-well capacities to share the overflow drain electrode, the three switch transistors and the three capacitors corresponding to the three switch transistors are added, and the capacitors are selectively opened or closed through the switch transistors, so that the output voltage of the liquid crystal display is improved. Therefore, the high dynamic range image sensor with multi-stage conversion gain is realized.

Description

technical field [0001] The present invention relates to the field of image sensors, in particular to a high dynamic image sensor and a pixel unit. Background technique [0002] In different real scenes, there is a very large variation range of light intensity. Especially for surveillance, vehicle and other scenes, the change of light and shade is very common. In order to adapt to different scenarios, the image sensors used in these scenarios need to have a large enough dynamic range to record as much image detail as possible. High Dynamic Range (HDR, High DynamicRange) has different design requirements for sensor pixels under different brightness. At high brightness, recording details requires the pixel's photodiode (PD, Photodiode) to have as large a full-well capacity (FWC, Full-well Capacitance) as possible. At low brightness, the capacitance of the floating diffusion region (FD, Floating Diffusion) needs to be as small as possible to obtain as large a conversion gain ...

AI Technical Summary

Problems solved by technology

This poses a great challenge to the circuit design of the image sensor

At the same time, the two gears with huge differences cannot provide the best conversion gain in the entire light intensity range, resulting in the loss of image details in scenes with medium light intensity

Images