Coordinate detecting apparatus
US4680430A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 1985 |
| Grant date | Jul 14, 1987 |
| Priority date | — |
| Expiry date | Feb 27, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/045
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A coordinate detecting apparatus for determining the coordinate data of a point on a plane by indicating the point with a touch of a fingertip or other load to the point. The apparatus comprises a transparent resistive film forming the plane (touch panel) and a buffer circuit operating as a voltage follower circuit having substantially infinate input impedance. The buffer amplifier is operatively connected between each selected pair of facing ends of a substantially rectangular region of the resistive film, and equalizes the potentials at the ends. The change of the impedance between one of the ends and the ground is detected in accordance with the touch of the fingertip to the touch panel and is used as an original coordinate data. Further modifications concerning the avoidance of degradation in the detection quality due to fluctuations of the impedance provided by the touch of a fingertip, for example, and the methods to perform 2-dimensional coordinate detection are described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.