Self-scanning MDS-integrated photosensor strip

Multielement MDS (metal-dielectric-semiconductor)-integrated photo-sensor strips are one of the new advances of semiconductor MDS technology. The most widespread types of these devices are photosensors based on CCD (charge-coupled devices) MDS-photodiode sensors and also structures of the photodiode-CCD-register type. If charge-coupled devices and photodiode sensors are compared, the advantages of MDS-photodiode sensors should include higher sensitivity, especially in the blue region of the spectrum, and higher homogeneity of sensitivity; the more significant disadvantages should include the dependence of video output capacitance on the number of elements connected to the output bus and, as a result, a reduction of the output signal voltage and an increase of noise. The effect of output bus capacitance can be reduced by introducing a preamplifier based on an MDS transistor into each photocell, which is connected by a source repeater scheme. The presence of a preamplifier uncouples the low signal current of the photodiode and the high capacitance of the output bus.