High-resolution, scalable multi-touch sensing display systems and processes based on frustrated total internal reflection employ an optical waveguide that receives light, such as infrared light, that undergoes total internal reflection and an imaging sensor that detects light that escapes the optical...http://www.google.co.uk/patents/US20080179507?utm_source=gb-gplus-sharePatent US20080179507 - MULTI-TOUCH SENSING THROUGH FRUSTRATED TOTAL INTERNAL REFLECTION
