| 摘要 |
A Contact Image Sensor (CIS) system utilizing a phototransistor sensing element that consists of a mechanism to pre-charge or inject a "background charge" into the storage node and allow the charge to reset through the same output base-to-emitter junction. This pre-charge and reset process removes the residual image and replenishes the charge lost by the base-to-emitter sub-threshold leakage current. Furthermore, the reset of the injected charge through the same output base-to-emitter junction automatically sets the phototransistor to an initial dark level, which is at the start of a linear region of the response versus illumination curve, and thus substantially improves the photo-response linearity.
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