Patent ID: 8022941

Claim:
A method of detecting touch on a touch-screen surface, comprising: providing a transparent slab, the transparent slab comprising a top surface and a bottom surface, and at least one side edge; injecting light into the transparent slab by placing at least one light source on the at least one side edge of the transparent slab, the at least one light source being placed so as to cause light injected in the transparent slab to be totally internally reflected in the transparent slab so that the top surface and the bottom surface of the transparent slab emit a minimum amount of light; receiving touch on the transparent slab with a body part of the user, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user; and capturing with a camera the portion of the light refracted into the body part of the user due to the touch of the body part on the transparent slab, wherein the camera is a shutter camera, the method further comprising: turning the at least one light source on; capturing a first video frame with the shutter camera so as to capture ambient light and the portion of the light refracted into the body part of the user; turning the at least one light source off; capturing a second video frame with the shutter camera so as to capture the ambient light; and subtracting the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab.