Amorphous photo-detecting element with spatial filter

摘要

In this sensitive, relatively inexpensive to manufacture, photo-detector, one surface of an amorphous silicon photovoltaic element is bonded to a thin transparent conductive layer formed on an insulating base. A conductive pattern is formed on the opposite surface of the element. The conductive layer may be formed of indium-tin oxide (ITO) and the photovoltaic element may be an element with an intrinsic semiconducting layer between p and n doped layers. The photovoltaic element generates component currents in response to photons passing through the transparent base and conducting layer. Those current components flowing predominantly in a direction at right angles to the photovoltaic element surfaces are summed by the conductive pattern which acts as a spatial filter, responsive to desired ones of these components and relatively unresponsive to other current components. The spatial filter conductive pattern and the transparent conducting layer may be coupled as the input to a suitable high impedance current detector.