A light-detecting device and method for converting optical radiation on switched conductivity diodes. The device comprises one or more photosensitive cells connected to address and signal lines, each cell comprising the following elements connected in series: a photodetector, an initial charge input circuit, a charge converter for converting the charge generated by the photodetector signal in addition to the initial charge into photodetector output voltage, a comparator which converts the difference between the photodetector output voltage and reference voltage into a digital cell signal, a reading circuit for reading the digital cell signal through the address lines and the signal lines, a circuit for generating digital codes of the cell signal, a random access memory for storing the digital codes, a reading circuit for reading the digital codes of the cell signals on one or more outputs of the light-detecting device.