Direct conversion x-ray imaging device with strip electrodes

Abstract

A flat panel X-ray imager using an amorphous selenium detector which uses a dielectric layer within the X-ray conversion layer to form an interface between the X-ray conversion layer and the high voltage bias electrode. To accomplish the removal of trapped counter charges at the dielectric/selenium layer, a plurality of discrete or strip electrodes are provided in contact with the dielectric layer and which are electrically coupled into distinct groups. During X-ray exposure, a high bias voltage is applied to all groups of strip electrodes. Following X-ray exposure and image readout, the groups of strip electrodes are energized using a plurality of differently-phased energization signals to drive trapped counter charges toward 'gutter' strip electrodes at the sides of the detector. A second embodiment of the flat panel X-ray imager includes sandwiching the discrete electrodes in a dielectric layer applied against the selenium layer and including a continuous electrode on the opposite side of the dielectric layer. Application of a high voltage bias to the continuous electrode results in an electric field in the selenium layer that is smoothed during X-ray acquisition. Discrete electrode energization to drive trapped counter charges to the gutter electrodes occurs while the high voltage bias is present.