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:
Jun. 18, 1991
Filed:
Dec. 08, 1986
James L Tallman, Hillsboro, OR (US);
Terry G Sherbeck, Aloha, OR (US);
Tektronix, Inc., Beaverton, OR (US);
Abstract
A system for providing input to a computer comprises a touchscreen apparatus for generating a grid of horizontal and vertical light beams and producing a set of output signals, each indicating whether a corresponding one of the light beams strikes an object. A scanning device repeatedly scans the states of the output signals, stores data representing the last scanned state of each output signal, and transmits a first interrupt signal to the computer whenever the state of any one of the output signals changes. In response to the interrupt signal, the computer reads the stored scan data, determines whether the data indicates that a horizontal and a vertical light beam is striking an object, and if so, sets parameter values to identify the horizontal and vertical light beams. In response to a second interrupt signal periodically generated by a clock, the computer determines whether or not the parameter values have remained constant for a predetermined period, and if so executes a routine responsive to the parameter values.