The precision infrared position detector apparatus uses an information display device that has a substantially cylindrical shaped screen to limit curvature of the screen to a single dimension. In addition, to compensate for this curvature, a flexible printed circuit board is used to align the row of...http://www.google.de/patents/US4891508?utm_source=gb-gplus-sharePatent US4891508 - Precision infrared position detector apparatus for touch screen system
