Particulate spacers for inhibiting Newton rings in touch sensitive overlays
US4696860A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 26, 1985 |
| Grant date | Sep 29, 1987 |
| Priority date | — |
| Expiry date | Sep 26, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31645
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Fine particles, preferably of brown alumina (approximately 96% Al.sub.2 O.sub.3), are disposed between closely spaced and normally parallel surfaces of two adjacent transparent layers, such as are typically found in a touch sensitive overlay (TSO). The particles are preferably of a size within the range 3-100 microns, and are distributed in a density preferably in the range 300-3,000 particles per square inch, so that the larger particles are in simultaneous contact with both the parallel surfaces. Local pressure on a TSO panel with this distribution of particles of non-uniform size allows operation of the panel without the generation of distracting Newton rings between the surfaces contacting the particles. These particles may be conveniently sprayed onto either of the parallel surfaces in suspension with a fluid carrier that evaporates to leave the particles adhering to the sprayed surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.