04346376 is referenced by 122 patents and cites 12 patents.

A touch sensitive device is arranged with substantially parallel surfaces inside which light from a synchronized source, such as a CRT, can become trapped by total internal reflection. The edges of the device are fitted with photodetectors which respond to the entrapment of light within the surfaces. The top surface is arranged so that a touch of the device at a particular point will cause a medium change on the surface at that point. The medium change causes light to become entrapped within the surface by total internal reflection thus making it possible, by comparing the photodetector output with the CRT raster position, to determine the exact surface position of the touch. Using this arrangement, positional determination is uneffected by raster drift.

Title
Touch position sensitive surface
Application Number
6/140716
Publication Number
4346376
Application Date
April 16, 1980
Publication Date
August 24, 1982
Inventor
James B Mallos
Freehold
NJ, US
Agent
David H Tannenbaum
Assignee
Bell Telephone Laboratories Incorporated
NJ, US
IPC
G08B 5/36
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