Abstract: In one aspect, the present invention provides a touch input system for use with an information display system. The touch input system includes a frame have four sides defining a touch input area. On each side is positioned an array of light emitting devices. In a preferred embodiment, the light emitting devices are organic light emitting diodes. A light transmissive prism is positioned along each array of light emitting devices such that light emitted from the light emitting devices is directed across the touch input area. The system also includes light detection device positioned at each corner of the frame.

Abstract: A touchscreen is constructed directly on the glass surface of a cathode ray tube (CRT). To solve the problem of insufficient space between the CRT's bezel and frontal region to accommodate the transducers for the touchscreen, the transducers are moved away from the frontal region, to the highly curved shoulder region of the CRT. To preserve acoustic signal strength, the positioning of the transducers is chosen to take advantage of the fact that an acoustic wave on a non-Euclidean surface travels along a geodesic path. Allowance is also made for the acoustic lens and prism effect of the corner regions of the CRT, where the transducer may be located.

Abstract: An effective seal for protecting a touchscreen and associated electronics from liquid infiltration, the seal being placed between the housing and the surface of the touchscreen and configured to surround the useful touchscreen area. The seal is preferably formed of a closed cell foam covered on the surface which contacts the touchscreen surface with a liquid impervious barrier, or an expanded polymer such as expanded PTFE. The seal may be secured to the bezel edge by a transfer adhesive coating applied to the bezel edge, except for a relatively thin edge strip along the inner edge of the bezel end, so that substantially no adhesive is present on a free surface of the seal body proximate to the window aperture of the bezel. Preferably, a smooth surface is provided for adhering the seal body to the bezel. The seal body may be compressed between the bezel and touchscreen surface to effect a seal.