Patent ID: 8791926
Filing Date: 2014-07-29
Classification: G06F

Abstract:
1. A projection touch system, configured for detecting a position of a touch object, comprising: an invisible light source, emitting an invisible light beam; a projection panel, wherein the invisible light source is disposed at a first side of the projection panel, comprising: a transparent plate; and a fluorescent film, disposed between the transparent plate and the invisible light source, and the invisible light beam scans back and forth on the projection panel, wherein when the invisible light beam penetrates through the transparent plate and the fluorescent film, the fluorescent film excited by the invisible light beam emits a first fluorescent light beam, wherein when the touch object is near or touched to the projection panel from a second side of the projection panel opposite to the first side and the invisible light beam reaches to the touch object, at least a portion of the invisible light beam is reflected by the touch object back to the fluorescent film and the fluorescent film excited by the invisible light beam emits a second fluorescent light beam; a light detector, disposed at the first side of the projection panel to detect the second fluorescent light beam relative to the first fluorescent light beam by an intensity level; and an analyze unit, finding the position of the touch object according to the first fluorescent light beam and the second fluorescent light beam detected by the light detector.