Tracer for electrographic surfaces
US4707572A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 1986 |
| Grant date | Nov 17, 1987 |
| Priority date | — |
| Expiry date | Oct 22, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/03543
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An improved tracer for use with electrographic surfaces which employs reticle components including crosshairs and a sighting circle which additionally functions to provide capacitive coupling. Formed of a conductive material such as chromium, these components are geometric regular shape and somewhat concentrated at the center portion of the reticle targeting center. As such, the device is capable of achieving a close correspondence between actual physical targeting location and resultant digitized coordinate readout. These components further achieve an avoidance of inaccuracies due to active surface border influences. The reticle-capacitive coupling components are placed on one side of a transparent disk, the opposite or upwardly disposed surface of which is coated with a transparent electrically conductive material such as indium tin oxide. This upwardly disposed conductive layer is coupled with ground and there results a dissipation of spurious signals which otherwise may influence the performance of the device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.