Touch panel with automatic nulling
US4707845A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1986 |
| Grant date | Nov 17, 1987 |
| Priority date | — |
| Expiry date | Aug 26, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0418
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A touch panel has panel scanning signals selectively applied to the four sides of a touch sensing surface of the panel so as to establish alternating current voltage gradients in desired directions across the touch sensing surface. When the panel is touched, touch signals result and are utilized by a touch location circuit in determining the location of touch. The impedence touch current resulting from a user's touch may also be determined and used. The touch panel circuit automatically compensates for any variations in touch signals which occur when the touch panel is untouched and automatically nulls the touch signals under such circumstances to enhance the accuracy of touch location determination.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.