A display device has an array of pixels (10) comprising light emitting display elements (20), for example EL elements, carried on a substrate (50) and associated light sensing elements (40) responsive to light emitted by the display elements. The light sensing elements each comprise a gated photosensitive...http://www.google.de/patents/US20010052597?utm_source=gb-gplus-sharePatent US20010052597 - Light-emitting matrix array display devices with light sensing elements
