Light guide
US5053928A · kind A · utility
34Cited by
5References
14Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 15, 1990 |
| Grant date | Oct 1, 1991 |
| Priority date | — |
| Expiry date | Aug 15, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2219/0622
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A light guide for illuminating a keyboard or keypad from behind comprises a transparent grid-like plate having an array of apertures in each of which is accommodated a respective key of the keyboard/keypad. The transparent plate comprises an integral lens aligned with a reflector for directing light from an external source into the plane of the plate. Various plane reflecting surfaces are provided for reflecting the light in a localized path completely surrounding each of the apertures. This arrangement enables the keys to be illuminated with a high degree of uniformity using only relatively few distributed light sources.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.