Display panels are provided which enable effective document scanning, information display, and entry of information using a stylus. The panels include (in the same panel) light emitting and light detecting functions which are arranged to permit effective scanning, display, and stylus reading techniques. In one aspect there is a two-dimensional panel for scanning information at a scanning surface. The panel has a light emitting layer and a light detecting layer. The light emitting layer is configured to emit light onto the scanning surface at selected pixel locations in response to electrical signals, each electrical signal being impressed at a selected pixel location, the layer having optical apertures defining corresponding optical paths at the pixel locations for light to exit the opposite side of the layer from the scanning surface. The light detecting layer is configured to detect light exiting the layer at pixel locations. The light emitting layer is between the light detecting layer and the scanning surface.