Patent ID: 8669951

Claim:
An optical touch panel, comprising: a substrate, having a surface; a single planar light generator, disposed outside the surface of the substrate for generating a planar light; wherein an illuminating range of the planar light covers a range of the surface of the substrate; at least a retro reflector device, disposed on at least a side of the substrate for reflecting the planar light; a single photo sensor array, disposed outside the surface of the substrate for sensing the reflected planar light and generating a reflected light distribution information; and a signal processing unit for performing a touch input calculating procedure to calculate a coordinate of a touch input position of a touch input device based on the reflected light distribution information generated by the single photo sensor array, wherein the touch input calculating procedure includes: providing a radius (a) of the touch input device; determining a central azimuth angle (θ), a first boundary azimuth angle (θ 1 ), and a second boundary azimuth angle (θ 2 ) of the touch input position based on the reflected light distribution information; calculating a distance (R) between the single photo sensor array and the touch input position by an equation 1: R = a sin ⁡ ( θ ⁢ ⁢ 2 - θ ⁢ ⁢ 1 2 ) ; and calculating the coordinate of the touch input position by an equation 2: X=R sin θ and an equation 3:Y=R cosθ, wherein X is a horizontal coordinate of the touch input position and Y is a vertical coordinate of the touch input position.