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:
Sep. 26, 1978
Filed:
Aug. 18, 1976
Eugene Stewart Schlig, Somers, NY (US);
George Raymond Stilwell, Jr, West Nyack, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A light pen detection and tracking scheme for detecting and tracking both 'on' and 'off' cells with a single cursor voltage waveform in an AC gas discharge display panel. The special cursor voltage waveform is applied to the panel during the sustain cycle, in either a line-by-line or binary scanning fashion, to momentarily fire both 'on' and 'off' cells so that they may be detected by the light pen without a loss of the memory state of the cells. A cross-hair cursor is automatically displayed at the pen position when the search scan is complete. Since both 'on' and 'off' cells are detected, the system can respond to pen motion by repeating the search to reacquire the pen, so that no special tracking strategy is needed.