Omnivision Technologies, Inc.

Tomas Geurts

Andreas Suess

Tiejun Dai

Zhe Gao

Ling Fu

Fixed pattern noise (FPN) reduction techniques in image sensors operated with pulse illumination are disclosed herein. In one embodiment, a method includes, during a first sub-exposure period of a frame, (a) operating a first tap of a pixel to capture a first signal corresponding to first charge at a first floating diffusion, the first charge corresponding to first light incident on a photosensor, and (b) operating a second tap of the pixel to capture a first parasitic signal corresponding to FPN at a second floating diffusion. The method further includes, during a second sub-exposure period of the frame, (a) operating the second tap to capture a second signal corresponding to second charge at the second floating diffusion, the second charge corresponding to second light incident on the photosensor, and (b) operating the first tap to capture a second parasitic signal corresponding to FPN at the first floating diffusion.

Fixed pattern noise reduction in image sensors operated with pulsed illumination

An imaging system includes a pixel array with odd and even pixel cells. Each of the odd and even pixel cells includes a photodiode, a floating diffusion, a transfer transistor, a reset transistor, a lateral overflow integration capacitor (LOFIC), and an overflow gate (OFG) transistor. The imaging system further includes a readout circuit with a sample and hold (SH) circuit and an analog to digital converter. The OFG transistor of each of the odd and even pixel cells is configured to direct the image charge photogenerated by the respective photodiode away from the respective transfer transistor and reduce photodiode exposure shift during LOFIC readouts during a global transfer period.

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Santa Clara, CA, United States of America

Tomas Geurts