A ‘locate-and-select’ touch screen

A touch screen has been developed which senses finger position by the obstruction of a network of infra-red beams passing in front of the screen. As this system does not use touch sensing per se, it becomes possible to introduce a second level of activation based on finger pressure. The major attraction of the proposed scheme is that it allows the desired item to be located before it is selected; feedback is provided to confirm the location. In addition, the response of the terminal to the selection can be programmed to simplify the driving software, and to provide compatibility with conventional terminals.