Touch detection systems and methods are described. The system comprises a light guiding sheet, a light source, a reflective layer and a detector. When a fingertip or other suitable object is pressed against the light guiding sheet, light which is undergoing total internal reflection within the sheet...http://www.google.de/patents/US20090128499?utm_source=gb-gplus-sharePatent US20090128499 - Fingertip Detection for Camera Based Multi-Touch Systems
