Desk-top calculator keyboard switch
US4180711A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 14, 1977 |
| Grant date | Dec 25, 1979 |
| Priority date | — |
| Expiry date | Sep 14, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2231/002
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic desk-top calculator includes a bottom casing for the calculator on the inner surface of which bottom casing there are provided fixed contacts, and a flexible plate having thereon pairs of contacts provided with wiring conductors therefor. These pairs of contacts are so arranged at the positions in registry with the fixed contacts as to form a matrix. The fixed contacts act as bridging contacts and comprise electrically conductive material containing carbon particles. The pairs of contacts and wiring conductors have a first electrically conductive layer. An insulative layer of moisture-resistive material overlies the first conductive layer except those terminal ends of the wiring conductor which serve as contacts or electrical connectors. The exposed portions of the first conductive layer which function as switch contacts have an additional layer of electrically conductive material containing carbon particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.