Sign illumination system and method
US5818640A · kind A · utility
49Cited by
5References
11Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 30, 1997 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Jan 30, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09F13/0472
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This relates to a system for and method of illuminating a sign, so that drivers and observers may easily recognize and read the sign and billboard. The apparatus employs an external illumination source that is easy to inspect and maintain. The illumination source and the sign or billboard are separately installed from each other. Light emitted from the illumination source forms an incident angle (.theta.) in the range of 0.degree. to about 30.degree. at any point on the road sign. A road sign area of the sign is made of a retroreflective sheet having a wide observation angle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.