Electrostatic tablet writing stylus
US4158747A · kind A · utility
21Cited by
1References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1978 |
| Grant date | Jun 19, 1979 |
| Priority date | — |
| Expiry date | Jun 26, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/03545
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An improved device for capacitively detecting signals generated in a writing table by a grid of conductive wires that produce a varying electrostatic field near its surface to be picked up through a stack of paper with the table functioning as one plate of a capacitor, and a conductive stylus as the other plate. The improvement consists of grounding the stylus, which has an extended body portion surrounded by a tubular member, extending the tubular member to a point very near the stylus tip where it functions as the second plate of a capacitor, and connecting the tubular member to a preamplifier mounted in the device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.