Electrographic apparatus
US4600807A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 26, 1984 |
| Grant date | Jul 15, 1986 |
| Priority date | — |
| Expiry date | Oct 26, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/045
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An electrographic apparatus utilizing a resistive layer which operates in conjunction with a stylus or tracer. Either the resistive layer or the cursor may be excited from an a.c. source to develop coordinate-defining electrical signals. A sequence of border switching arrays is provided which minimizes the number of switching components required for any given resistive layer or tablet architecture. Improved accuracy is achieved through an automatic gain control and gain election procedure as well as through the imposition of a positive offset signal and a control technique wherein the offset values of the circuit are cyclically evaluated and the coordinate data information is adjusted in accordance with that evaluation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.