Patent ID: 8274497

Claim:
A data input device comprising: a basic image, which is projected on a projection face of an xz plane of an operational coordinate system, having at least one input zone for being processed an input operation; a digital camera having a reference coordinate system with an x′z′ plane parallel to said xz plane, and having a lens capable of taking an input image disposed on said input zone at the time of said input operation being processed and a reference image disposed on the same input zone corresponding to said xz plane respectively; a microprocessor being electrically connected to said digital camera for detecting said input image and said reference image and generating an input signal corresponding to said input image if said detected reference image is an image showing said input zone being touched; wherein a first mirror is installed in front of said lens to reflect said input image for said input image being taken by said digital camera, and a second mirror is installed in front of said lens to reflect said reference image onto an elevation within a preset short distance from said xz plane for said reference image being taken by said digital camera prior to said microprocessor is capable of detecting said reference image and generating said input signal; the input image and the reference image are taken at two different angles; each light path between source of input image and reference image and the digital camera is produced by single reflection of the first mirror and second mirror respectively; wherein, the first and second mirrors are disposed at two different locations to reflect light beams in different directions to the same digital camera via different directions.