Patent ID: 8338725

Claim:
An apparatus for touch detection, comprising: (a) a touch panel characterized with X-Y coordinates; (b) an imaging device associated with the touch panel and configured to acquire an image of the touch panel and transfer the acquired image into a signal array that is a function of an angle; and (c) a processor in communication with the imaging device for receiving the signal array therefrom, comparing a peak signal of the signal array with a predefined threshold and if the peak signal is greater than the predefined threshold, obtaining the peak's width, W, and angle, Θ, relative to the touch panel so as to determine the location (X, Y) of a pointer in the touch panel in the forms of: X=R ×cos(Θ), Y=R ×sin(Θ), wherein R is a distance of the pointer and the imaging device, and satisfies the relationship of W=A×R B +C, wherein A, B and C are constant coefficients.