Patent ID: 7514688

Claim:
A photon-counting imaging device for single xray counting comprising: a) a layer of photosensitive material; b) a source of bias potential; c) a source of a threshold voltage supply; d) an N×M array of photodetector diodes formed using said layer of photosensitive material, each of said photodetector diodes having a bias potential interface and a diode output interface, said bias potential interface of each photodetector diode being connected to said bias potential; e) an NXM array of high gain, low noise readout unit cells, one readout unit cell for each photodetector diode; f) each readout unit cell including: an input interface connected to said diode output interface; a high-gain voltage amplifying unit including a comparator unit; and a digital counter unit including a digital counter and a digital counter output interface connected in series, each digital counter unit counting an output signal of the comparator unit, said output signal being proportional to a number of electron/hole pairs generated by a photon in the respective photodetector diode; g) a multiplexing unit including a row select and a column select circuit allowing to access each readout cell unit, to read out the digital data as actually stored in the digital counter to the digital counter output interface: h) each digital counter output interface connected to an output bus; and i) said output bus being connected to a data processing unit controlling the multiplexing unit.