Stylus position digitizer using acoustic waves
US5691959A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 6, 1994 |
| Grant date | Nov 25, 1997 |
| Priority date | — |
| Expiry date | Apr 6, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S367/907
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A digitizer uses acoustic waves originating from a stylus to determine the position of the stylus on a plate. The acoustic waves are introduced into the plate from the tip of the stylus and are detected by a plurality of detectors positioned at various points along the periphery of the plate. By sensing differences in the arrival times of the acoustic waves at the detectors, a microprocessor calculates the position of the stylus. In a preferred embodiment using a non-tethered stylus, four detectors are positioned at the corners of a rectangle, and the time differences are used as addresses in a lookup table, which is programmed to contain x and y coordinates corresponding to the time differences, Different embodiments may detect only the "fast" symmetrical waves or only the "slow" antisymmetrical waves generated in the plate, or may use the arrival times of both types of waves to determine the stylus position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.