Graphic input system
US4777329A · kind A · utility
95Cited by
8References
20Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 24, 1987 |
| Grant date | Oct 11, 1988 |
| Priority date | — |
| Expiry date | Aug 24, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/03545
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A graphic input system determining position coordinate data of a mobile element on a writing surface by measuring the transit times of ultrasonic signals and an electromagnetic signal. The mobile element may comprise either a writing instrument or an eraser. The electromagnetic signal contains information that represents the color of ink used in the writing instrument and identifies the portion of the eraser in contact with the writing surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.