Method and apparatus for detecting a multitouch event in an optical touch-sensitive device

摘要

A touch sensitive optical control device comprising a set of light emitters 14, 22 and light detectors 18, 24 arranged relative to a touchable surface 30 such that light transmitted by the emitters is received by the detectors along multiple intersecting beams which pass transversely of the surface and touching the surface at a beam interrupts the light transmitted along the beam. Candidate touch points T1, T2, F1, F2 are defined at the intersections of interrupted beams and are confirmed or not as actual touch points by examining test beams 40, 42, 54, 56 near to or coincident with the candidate touch point.

主权项

1. A method for determining a touch event on a touch-sensitive optical device comprising a plurality of optical emitters and a plurality of optical detectors, the optical emitters and the optical detectors defining therebetween a plurality of optical beam paths forming an optical beam intersection pattern that extends over an area and is symmetrical about at least one axis of the area, the method comprising the steps of:
detecting modulation of energy transmitted along each of a pair of optical beam paths; assigning a candidate touch point at the intersection of said pair of modulated beams; retrieving stored data regarding symmetric beams on a first side of the at least one axis; extrapolating the symmetric beam data to identify predetermined other beams on a symmetrically opposite side of the first axis, wherein the predetermined other beams are identified based on the assigned candidate touch point; analyzing the predetermined other beams; and responsive to said analysis, determining whether the candidate touch point is an actual touch point.