Digitizing tablet system including a tablet having a grid structure made of two orthogonal sets of parallel uniformly sized and spaced U shaped loops of conductive material
US4694124A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 9, 1985 |
| Grant date | Sep 15, 1987 |
| Priority date | — |
| Expiry date | Dec 9, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/046
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A digitizing tablet system having a stylus which is inductively coupled to a grid is disclosed. The grid includes a first plurality of narrow uniformly sized and spaced U shaped loops of conductive material disposed to define a first coordinate axis of the grid and a second plurality of narrow uniformly sized and spaced U shaped loops of conductive material disposed to define a second coordinate axis of the grid. One end point of each loop in each plurality of loops is connected to a common conductor which serves as one output terminal for that plurality of loops. The other end point of each loop in the same plurality of loops is connected to a multiplexor whose output is connected to a conductor which serves as the other output terminal for that plurality of loops. Voltage signals induced in the loops when the stylus is positioned above the grid and a coil in the stylus is energized are processed to generate data signals corresponding to the position of the stylus relative to the grid structure. Since the loops are uniform in size and shape, nonlinearities in the relationship between the induced voltage and the computed stylus position from one loop to the next are eliminated. In …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.