Method for use in a digitizer for determining pen tilt
US5198623A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 27, 1991 |
| Grant date | Mar 30, 1993 |
| Priority date | — |
| Expiry date | Nov 27, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/04186
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A digitizer includes a tablet having an array of conductors, and a pen-shaped, coil-containing stylus. The digitizer applies an energizing signal to either the conductors or the stylus, which signal induces voltages in the other. Then, the digitizer detects the induced voltages corresponding to the conductors, which define a voltage waveform having a positive peak, a negative peak, and a zero-crossing therebetween. The digitizer corrects for pen tilt in determining stylus position on the tablet by determining a position value for the zero-crossing using voltages in a region between the positive and negative peaks of the waveform and generating a pen tilt correction value using the position value and voltages in a region outside the positive and negative peaks. Then, the pen-tilt correction value and a preferably cyclic-error-corrected value for the position of the zero-crossing are combined to yield a relatively accurate pen-tilt-compensated determination of stylus position. The pen-tilt value provided by the invention can also be used in other applications, e.g., hand-writing recognition and electronic calligraphy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.