An optical touch panel including a support defining a generally planar surface, an optical illumination assembly arranged along and above at least part of a periphery of the support to define a detection region, at least one light detector, arranged to detect changes in the light received from the optical...http://www.google.com.hk/patents/US7333095?utm_source=gb-gplus-share專利 US7333095 - Illumination for optical touch panel
