Coordinate determining device using spatial filters
US4963703A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 1989 |
| Grant date | Oct 16, 1990 |
| Priority date | — |
| Expiry date | Jul 18, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/046
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A digitizing tablet is disclosed in which two sets of circuitous conductive lines form grids each connected at one end to a surrounding conductive loop. All outputs are measured from the conductive loop as a multiplexor sequentially grounds the grids one at a time. The outputs are fed through linear spatial filters which are used to produce intermediate signals which are in turn combined to arrive at raw position signals for a position indicating coil located over the work surface. Separate sets of linear spatial filters may be used to produce two raw position signals differently responsive to tilt which can then be combined to arrive at a true position signal insensitive to tilt.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.