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AssigneeThomson-CSF
InventorsJean L. Berger, Marc Arques
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The disclosure concerns photosensitive matrices, and especially those using NIPIN or PINIP type phototransistors made of amorphous silicon. To prevent problems of remanence, due to the collecting of holes in the base after an illumination stage, it is proposed to follow the step for reading the illumination signal by a remanence erasure step in which the phototransistor is made conductive in forward or reverse bias, so as to inject, into the base, electrons which will eliminate the holes by recombination. Switching on by reverse bias proves to be more efficient than switiching on by forward bias. The invention is applicable notably to a matrix structure of rows and columns of photosensitive sites in which each site is formed by a NIPIN transistor made of amorphous silicon in series with a reading diode that may be put into reverse conduction.
A method of photoelectric detection wherein there is used, as a detection element, a phototransistor connected between a first electrode and a floating node, with a switch-over element connected between the floating node and a second electrode, the method including a detection step in which the phototransistor is biased in non-conductive mode and photoelectric charges generated in the phototransistor are stored at the floating node, and a reading step during which the switch-over element is made conductive and the stored charges are removed, a method wherein, after the reading step, a step is executed for the erasure of remanence, consisting in turning the phototransistor on.
A method for the erasure of the remanence of a photosensitive matrix, each photosensitive dot of which comprises a phototransistor as a photosensitive element and a reading diode, placed in series with the latter between a row conductor and a column conductor of the matrix, the reading diode and the phototransistor being capable of being placed in reverse conduction, wherein:
Dependencies are inferred from the claim text.