Patent ID: 8676007

Claim:
A light-based touch-sensitive surface, comprising: a housing; a surface attached to said housing for receiving touch input; a plurality of light sources in said housing for emitting light that crosses said surface; a plurality of light receivers in said housing for detecting the light emitted by said light sources; a curved lens adjacent to said surface through which the light emitted by said light sources passes, comprising first and second curved panels having substantially similar curvatures, wherein the light is refracted as it enters said first curved panel and is refracted again as it exits said second curved panel, the refraction upon exit being the inverse of the refraction upon entry, and wherein one of said panels is curved in a horizontal plane parallel to said surface and forms a curved rim for said surface; and a calculating unit in said housing, connected to said light receivers, for calculating a touch location based on an absence of light expected to be received by said receivers.