Switches and keyboards
US4839474A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1987 |
| Grant date | Jun 13, 1989 |
| Priority date | — |
| Expiry date | Dec 10, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2229/042
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A low profile switch or keypad has one or more touch buttons of circular or polygonal shape in plan formed integrally with and raised from a surrounding membrane of elastomeric material by a wall of resiliently deformable material of thickness and angle relative to the membrane so that the wall can flex under finger pressure on the or each button without deflecting the surrounding membrane. The membrane and at least the periphery of the button are relatively thick and the wall is relatively thin so that deformation during the keystroke is localized in the wall. The length of the wall is about equal to the keystroke and is relatively small compared to the width of the touch button. The junction between the wall and the membrane is located a distance greater than the keystroke above the lower surfaces of the membrane so that the wall passes overcenter during the keystroke resulting in a change in tactile sensation. The underside of each touch button is preferably formed with a convex contact pad dimensioned in relation to the button diameter and travel and the length of wall so that the contact pad makes surface to surface contact with conductors of an underlying circuit board.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.