Position detecting apparatus with coils of opposite loop direction
US5434372A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 19, 1993 |
| Grant date | Jul 18, 1995 |
| Priority date | — |
| Expiry date | Aug 19, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/046
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A position detecting apparatus includes a tablet and a position pointer. The tablet includes a plurality of electromagnetic wave generating/detecting apparatus. The generating/detecting apparatus generates an electromagnetic wave at specified points of time and detects electromagnetic wave at different points of time. The electromagnetic wave generating/detecting apparatus includes a first coil of a first direction with a first inductance value and a second coil of a second direction with a second inductance value. The first and second coils are coupled serially and closely adjacent to each other and the first inductance value is substantially equal to the second inductance value. Only the first coil is enabled when the electromagnetic wave generating/detecting apparatus is generating the electromagnetic wave, the first and second coils are both enabled when the electromagnetic wave generating/detecting apparatus is receiving the electromagnetic wave. Any interference sensed both by the first and second coils are offset and therefore a position detecting apparatus with high immunity from the electromagnetic interference is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.