| 摘要 |
A method and system for detecting the presence of an object at a touch pad device, wherein the touch pad device has a designated interaction area for allowing a user to use the object to interact with the touch pad device for inputting one or more functions in an electronic device. One or more groups of optical sensor components, each including an optical receiver and two light emitters positioned at opposite sides of the receiver such that when an object is present at the touch pad device, the changes in the receiver output can be used to determine the location of the object as a function of time. Preferably, the light emitters are operated in a pulsed mode so that the changes in the receiver output contain a frequency component so as to distinguish the changes due to the presence of the object and those of ambient light.
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