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. 12, 2001
Filed:
Jun. 04, 1998
Timothy V. Kalthoff, Tucson, AZ (US);
Bernd M. Rundel, Tucson, AZ (US);
Burr-Brown Corporation, Tucson, AZ (US);
Abstract
A touch screen digitizing system includes a touch screen unit including a first resistive sheet with opposed x+ and x− terminals and a second resistive sheet with opposed y+ and y− terminals, and an ADC having first and second reference input terminals. A first switch is coupled between a first reference voltage and the x− terminal, and a second switch is coupled between the x+ terminal and a second reference voltage for energizing the first resistive sheet. A third switch is coupled between the first reference voltage and the y− terminal, and a fourth switch is coupled between the y+ terminal and the second reference voltage for energizing the second resistive sheet. Switching circuitry couples an input of the ADC to the y+ terminal while the first resistive sheet is energized and the second resistive sheet is not energized, and also couples the input to the x+ terminal while the second resistive sheet is energized and the first resistive sheet is not energized. The structure provides continuous calibration of the full-scale analog touch screen output of the full-scale digital output of the ADC irrespective of sharply different variations in resistances of the switches and resistive sheets.