tdi photosensitive device and image sensor for suppressing image mismatch

Abstract

The TDI photosensitive device for suppressing image mismatch of the present invention is composed of K rows of separated TDI photosensitive sub-arrays integrated on the same chip, and the transfer corresponding to each TDI photosensitive sub-array is arranged in the gap between adjacent TDI photosensitive sub-arrays. circuit. The pixel signals collected by each TDI photosensitive sub-array are transferred to the outside through the transfer circuit, and the pixel signals of the TDI photosensitive sub-arrays in the 2nd to k rows are shifted externally to match the pixel signals of the same column, and then the pixels of each column The signals are accumulated to obtain a corrected image. The invention completely solves the problem of image mismatch, greatly improves the quality of TDI images, and can save the cost of later image correction.

Description

technical field [0001] The invention belongs to the technical field of integrated circuit image sensors, and in particular relates to a TDI image sensor. Background technique [0002] Time Delay Integration (TDI) is an imaging technology widely used in image sensors. The pixels of the sensor row expose the same part of the object successively, and finally the light signals of each column of pixels are accumulated to improve the photosensitive ability of the detector in the low-light environment, and make up for the shortcomings of the image sensor in the low-light environment that the energy acquisition is insufficient. The traditional TDI photosensitive device is an overall CCD array, which is divided into charge domain accumulation and digital domain accumulation according to the signal accumulation method. When the number of TDI stages of the image sensor is N, the charge-domain TDI technology directly accumulates the generated photoelectric charges N times, and the sign...

AI Technical Summary

Problems solved by technology

However, in specific applications, there are differences between the scanning direction of the image sensor and the motion of the object, such as the crosstalk of the image between the column pixels caused by the lateral motion, such as Figure 2a , Figure 2b As shown, this leads to a reduction in the resolution of the image sensor, and in severe cases, image smearing occurs, so image correction is required in the later stage

At the same time, because the charge domain TDI technology first accumulates the signal and then outputs it, the computer algorithm cannot fundamentally correct the image

At the same time, the TDI signal-to-noise ratio is positively correlated with its series, but the increase of the series will not only increase the complexity of layout design, but also rapidly reduce the chip yield

Although the digital domain mode can correct the image first and then accumulate the signal, since the signal will introduce readout noise during readout, the signal-to-noise ratio can only be improved times, the space for noise suppression is very limited

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