Coordinate input device
US5905489A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 1997 |
| Grant date | May 18, 1999 |
| Priority date | — |
| Expiry date | Feb 12, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0446
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An M-sequence signal is generated in an M-sequence generation circuit, and the M-sequence signal, which is successively delayed by a column-electrode driving circuit or a row-electrode driving circuit, is applied to a column-electrode group or a row-electrode group. A correlator finds a correlation between the M-sequence signal and a detection signal that has been detected by amplifying electrostatically induced voltage that appeared in the detection electrode of an electronic pen so that a position specified by the electronic pen is detected by a detection circuit as a coordinate signal. Thus, it is possible to obtain a coordinate detection signal having a superior S/N ratio without reducing the coordinate detection speed, and consequently to carry out a coordinate detecting operation with high precision.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.