| 摘要 |
A one dimensional image sensor is disclosed which has a series of photodiodes (S1-S3) to be electrically scanned by voltages (Vp1-Vp3) developed by a sawtooth voltage (Vd; V1, V2) for generating electric outputs representative of incident optical energy. The scanning voltages for the photodiodes have so far risen beyond their predetermined saturation points with an increase in the sawtooth voltage, deteriorating the image sensor response to low intensity optical input. For the elimination of this weakness of the prior art, there is provided a bias source (22; 122, 122') which generates a periodically varying bias voltage (Vb) in synchronism with the sawtooth voltage (Vd; V1, V2). The bias voltage has a series of ramps that are opposite in the direction of progress to the ramps of the sawtooth voltage, and so serves to prevent or reduce the undesired rises of the scanning voltages beyond their saturation points. <IMAGE> |
