Patent ID: 6061177
Filing Date: 2000-05-09
Classification: G06F

Abstract:
A touch screen input device, which comprises:a transparent sheet having a first surface and a second surface, the transparent sheet having an index of refraction greater than that of air, and the first surface being a smooth surface defining a touch surface of the touch screen input device;a diffusing surface imposed on the second surface of the transparent sheet;a light source positioned in proximity to the second surface so that the second surface is closer than the first surface to the light source, and positioned to project light onto the diffusing surface of the transparent sheet, and so that when light is projected onto the diffusing surface some light refracts as said some light passes through the diffusing surface and reflects within the transparent sheet when said some light reaches the first surface; anda camera positioned in proximity to the second surface so that the second surface is closer than the first surface to the camera, and positioned to image light emanating from the second surface of the transparent sheet;whereby reflection of light within the transparent sheet is interrupted where the touch surface is being touched and light emanating from the second surface is thereby reduced.