Touch screen has a very wide range of applications. Most of them are used in public information inquiries, for instance, service inquiries in telecommunication bureau, tax bureau, bank system, electric department, etc...Touch screen can also be used for entertainment and virtual reality applications too. Traditionally, touch screen was composed of pairs of infrared LED and correspondent receivers which were all installed in the screen frame. Arrays of LED were set in the adjacent sides of the frame of an infrared touch screen while arrays of the infrared receivers were fixed in each opposite side, so that the infrared detecting network was formed. While the infrared touch screen has some technical limitations nowadays such as the low resolution, limitations of touching methods and fault response due to environmental disturbances. The plastic material has a relatively high absorption rate for infrared light, which greatly limits the size of the touch screen. Our design uses laser diode as source and change the traditional inner structure of touch screen by using a light pipe with microstructures. The geometric parameters of the light pipe and the microstructures were obtained through equation solving. Simulation results prove that the design method for touch screen proposed in this paper could achieve high resolution and large size of touch screen.

Date Published: 5 November 2010
PDF: 5 pages
Proc. SPIE 7849, Optical Design and Testing IV, 78490R (5 November 2010); doi: 10.1117/12.869734

Published in SPIE Proceedings Vol. 7849:
Optical Design and Testing IV
Yongtian Wang; Julie Bentley; Chunlei Du; Kimio Tatsuno; Hendrik P. Urbach, Editor(s)