The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 08, 1989
Filed:
Jun. 25, 1987
Milan Bures, Tabaccoville, NC (US);
Paul P Kratochvil, Kernersville, NC (US);
John R Rowlette, Clemmons, NC (US);
AMP Incorporated, Harrisburg, PA (US);
Abstract
An input device which can be employed to input commands to a computer directly through a CRT display is disclosed. The input device employs a plurality of infrared light emitting diodes and phototransistors aligned in individual emitter-detector pairs. Infrared beams from the emitter cross the display field before striking the corresponding detector. Emitters and detectors are sequentially activated and each emitter is pulsed or modulated at a frequency different from the variation of ambient conditions during each emitter activation interval. The detection circuitry thus can distinguish the varying emitter signal from ambient or spurious variations. A number of pulses at the pulsed or modulated emitter frequency would be detected unless an opaque element were blocking the particular beam.