Patent ID: 8232511

Claim:
A sensing system adapted to sense a pointer and calculate a location of the pointer, comprising: a panel having a first plane and a first area located at the first plane, the first area being quadrangular and having a first boundary, a second boundary, a third boundary and a fourth boundary which are connected in order; a reflective element disposed at the first boundary and located on the first plane, the reflective element having a second plane substantially perpendicular to the first plane, the second plane being a reflective mirror plane and mirroring the first area to form a second area; an image sensor disposed at a corner at which the third boundary and the fourth boundary intersects and located on the first plane, a sensing range of the image sensor covering the first area and the second area; a processor electrically connected to the image sensor; a first light source disposed beside the image sensor; a first reflector disposed at the second boundary and located on the first plane, the first reflector being mirrored by the reflective element to form a second mirror image, the first reflector having a first retro-reflective surface, the first retro-reflective surface being adapted to reflect the light emitted by the first light source; and a second reflector disposed at the third boundary and located on the first plane, the second reflector being mirrored by the reflective element to form a third mirror image, the second reflector having a second retro-reflective surface, the second retro-reflective surface being adapted to reflect the light emitted by the first light source, the fourth boundary being mirrored by the reflective element to form a fourth mirror image; the reflective element, the first reflector, the second reflector and the fourth boundary surrounding the first area; the reflective element, the second mirror image, the third mirror image and the fourth mirror image surrounding the second area; and the first reflector, the second mirror image and the third mirror image being in the sensing range of the image sensor; wherein when the pointer approaches the first area and the pointer is mirrored by the reflective element to form a first mirror image such that the pointer and the first mirror image is in the sensing range of the image sensor and when a portion of the pointer adjacent to the first area, a portion of the first mirror image adjacent to the second area and the image sensor are not colinear, the image sensor senses the pointer and the first mirror image and the processor calculates the location of the pointer.