METHOD FOR ANALOGUE-TO-DIGITAL CONVERSION OF OPTICAL RADIATION ON SWITCHED CONDUCTIVITY DIODE AND PHOTODETECTOR FOR REALISING SAID METHOD Russian patent published in 2013 - IPC G02F7/00 H01L31/00 

FIELD: physics.

SUBSTANCE: method for analogue-to-digital conversion of optical radiation involves converting the radiation into photocurrent; integrating the photocurrent over the exposure time into an electric charge which changes the initial charge input before exposure; converting the resultant charge into signal voltage; comparing the signal voltage with a reference voltage and switching the comparator as the comparison result; generating binary signals, modulated on the time of switching relative the initial time; generating digital codes based thereon; storing the digital codes and successively sending said codes to outputs, wherein the initial charge is input into the switched conductivity diode by applying a voltage corresponding to the initial charge in the forward direction at the rate of change which causes injection of minority carriers, which does not exceed the level of triggering the switching diode into the conducting state, and the reference voltage applied is the corresponding sampling voltage at a variation rate sufficiently high to cause injection of minority carriers, needed for triggering thereof upon reaching voltage corresponding to the resultant charge, with given accuracy. The device which realises this method has one or more photosensitive cells connected to address and signal lines, each cell having series-connected photodetector, initial charge input circuit, charge converter for converting the charge generated by the photodetector signal, in addition to the initial charge, into output voltage of the photodetector, a comparator which converts the difference between the output voltage of the photodetector and a reference voltage into a digital cell signal, a circuit for reading the digital cell signal through address and signal lines, a circuit for generating cell signal codes, random access memory for storing digital codes, a circuit for reading cell signal digital codes on one or more outputs of the photodetector. In a cell, the photodetector, the initial charge input circuit, the charge converter and comparator are in form of a tunnel switching electrode in a MIS (metal, insulator, semiconductor) structure, one of the leads of which is connected to the address line and the other to the signal line.

EFFECT: high spatial resolution with high equivalent quantum efficiency.

9 cl, 3 dwg