Optical touch input system and method of establishing reference in the same

A method of establishing a reference in an optical touch input system, the method comprising:

• emitting light by emitters located at respective first and second corners of a display panel, and receiving direct light by a detector located at a third corner of the display panel;
• the detector at the third corner detecting respective first and second impulse signals generated by the direct light of the emitters located at the respective first and second corners;
• the respective first and second impulse signals corresponding to pixel positions of the detectors located at the third corners;
• and
• correlating the respective pixel positions of the respective first and second impulse signals with respective predetermined first and second reference angles of the display panel,
• wherein at least one of the predetermined first and second reference angles is 0 degree or 90 degrees, and the at least one of the predetermined first and second reference angles corresponds to one end of a region of interest of the display panel.

A method of establishing a reference in an optical touch input system, the method comprising:

• emitting light by emitters located at respective first, second, and third corners of a display panel, and receiving direct light by a detector located at a fourth corner of the display panel;
• the detector at the fourth corner detecting respective first, second, and third impulse signals generated by the direct light of the emitters located at the respective first, second, and third corners;
• the respective first, second, and third impulse signals corresponding to pixel positions of the detectors located at the fourth corner;
• and
• correlating the respective pixel positions of the respective first, second, and third impulse signals with respective predetermined first, second, and third reference angles of the display panel,
• wherein the first reference angle is 0 degrees, the third reference angle is 90 degrees, and the second reference angle is greater than the first reference angle and less than the third reference angle and
• wherein the first reference angle corresponds to one end of a region of interest of the display panel, and the third reference angle corresponds to another end of the region of interest.

An optical touch input system, comprising:

• a display panel;
• three or more optical sensor modules disposed at three or more corners of the display panel, each of the optical sensor modules with a detector and an emitter;
• a retro-reflector disposed corresponding to at least three sides of the display panel;
• and
• a touch controller having a first part for detecting touch and a second part for establishing a reference, wherein the reference is sensed by the detector of one optical sensor module with detecting a direct light from the emitter of another optical sensor modules,
• wherein the second part of the touch controller detects impulse signals from the emitters of the optical, sensor modules and detects pixels corresponding to the pixel positions of the detectors in the optical sensor modules, and correlates the pixels positions of the detectors to reference angles corresponding to corners in the display panel and
• wherein at least one of the reference angles is 0 degree or 90 degrees, and corresponds to one end of a region of interest of the display panel.