Abstract: The invention is directed to an X-Y co-ordinate detection system of the type which generates intersecting paths of radiation across a surface which may be, for example, a touch panel of the cathode ray tube type. Less expensive and more reliable operation is provided by developing the paths of radiation by use of radiation-emissive material disposed near at least one edge of the surface and excited by a flying spot of energy, such as an electron beam. In the preferred embodiment, strips of infrared emissive material are disposed on an internal surface of a cathode ray tube's panel and excited by overscanning the tube's electron beam to develop intersecting paths of infrared radiation across the tube's faceplate.