Touch panel with automatic frequency control
US4698461A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1986 |
| Grant date | Oct 6, 1987 |
| Priority date | — |
| Expiry date | Aug 26, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/045
- 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 adjusts the frequency of the applied panel signals to shift this frequency away from fixed frequency interference spectra, such as due to cathode-ray tube flyback signals, in the environment in which the touch panel is used. The touch location thereby minimizes the effects of such spectra on touch location determinations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.