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Global shutter control method for high dynamic range image sensor pixels

An image sensor, high dynamic range technology, used in image communication, color TV parts, TV system parts and other directions, can solve the problems of destroying high gain signal values, unable to achieve global exposure, etc., to eliminate reset noise, The effect of reducing dark noise

Active Publication Date: 2018-09-18
GPIXEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Using the above-mentioned 5-transistor high dynamic range image sensor pixel signal readout control method, the pixel will destroy the stored high-gain signal value during the second charge transfer, so global exposure cannot be achieved

Method used

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  • Global shutter control method for high dynamic range image sensor pixels
  • Global shutter control method for high dynamic range image sensor pixels
  • Global shutter control method for high dynamic range image sensor pixels

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0063] Such as Figure 8 As shown, the device for realizing the global shutter control method of the high dynamic range image sensor pixel of the present invention includes a global gate transistor M6, a photodiode PD, a charge transfer control transistor M1, a reset transistor M3, a lateral overflow gate switch structure, a buffer amplifier M4 and Row select transistor M5. The gate TX2 of the global gate transistor M6 of each pixel of the image sensor is controlled by the same signal. The drain of the global gate transistor M6 is connected to the reset voltage VD3, the source is connected to the cathode of the photodiode PD, and the cathode of the photodiode PD is connected to the source of the charge transfer control transistor M1 at the same time; the drain of the charge transfer control transistor M1 is connected to the floating diffusion area FD; the lateral overflow gate switching structure is composed of a switching transistor M2, and the floating diffusion region FD i...

Embodiment 2

[0069] Such as Figure 10 As shown, the difference between the device for realizing the global shutter control method of the high dynamic range image sensor pixel of the present invention and Embodiment 1 is that the source of the reset transistor M3 is directly connected to the floating diffusion region FD; the lateral overflow gate switch structure is composed of A switch transistor M2 is formed, the floating diffusion region FD is connected to the source of the switch transistor M2 at the same time, the drain of the switch transistor M2 is connected to one end of the storage capacitor C1, and the other end of the storage capacitor C1 is connected to the power ground. The structure of the rest of the device is the same as in Embodiment 1.

[0070] In this embodiment, the working sequence and the potential of each part of the exposure process are as follows: Figure 7 , Figure 9a ~ Figure 9e Shown, is identical with embodiment 1.

Embodiment 3

[0072] Such as Figure 11 As shown, the device for implementing the global shutter control method for high dynamic range image sensor pixels of the present invention is different from Embodiment 1 only in that the lateral overflow gate switch structure is composed of a high dynamic transistor HDR, and the channel of the high dynamic transistor HDR As a charge storage area directly, the storage capacitor C1 is omitted.

[0073] The structure of high dynamic transistor HDR is as follows Figure 14 shown.

[0074] The gate area S of the high dynamic transistor HDR satisfies formula (1);

[0075] Q max / (ΔV max ×Cox)≤S≤2×Q max / (ΔV max ×Cox) (1)

[0076] where Q max is the maximum expected value of the amount of charge stored in the channel after the second transfer of photogenerated electrons, ΔV max is the maximum expected value of the second photoelectron transfer signal, and Cox is the gate oxide capacitance per unit area.

[0077] The working sequence of this embodi...

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Abstract

The invention relates to a global shutter control method for a high dynamic range image sensor pixel. The method applies a lateral overflow gate technology in the high dynamic range image sensor pixel, and reduces the on-voltage of the lateral overflow gate switch to a set value during charge transfer. , so that when the first charge transfer is performed, the high and low gain signal values ​​can be obtained by floating the diffusion region and the charge storage region in the pixel at the same time, without the need for the second charge transfer. With this method, the image sensor performs a global shutter, all pixels start exposure at the same time, and stop exposure at the same time. After exposure, after a signal transfer, different gain signals are obtained in the floating diffusion area and the charge storage area. The two signals are stored in the pixel and wait to be read line by line to complete the global shutter. Using this control method, all pixels have the same start and end exposure time, and the picture will not be distorted when shooting high-speed moving objects.

Description

technical field [0001] The invention belongs to the technical field of semiconductor image sensing, and in particular relates to a global shutter control method for high dynamic image sensor pixels. Background technique [0002] Dynamic range is an important indicator of image sensors, and the prior art 5-transistor high dynamic range image sensor pixels such as figure 1 As shown, it includes photodiode PD, charge transfer control transistor M1, switch transistor M2, capacitor C1, reset transistor M3, buffer amplifier M4 and row select transistor M5. The pixel operation timing is as figure 2 As shown, its working principle is as follows: [0003] 1. At time t1, the charge transfer control transistor M1 is closed, the switch transistor M2 is closed, the reset transistor M3 is closed, and the photodiode PD is reset. After that, the charge transfer control transistor M1 is turned off, and the pixel starts to be exposed; [0004] 2. Before the end of the exposure, turn on t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04N5/353H04N5/357H04N5/235
CPCH04N23/73H04N25/53H04N25/616
Inventor 王欣洋马成周泉
Owner GPIXEL