Transparent eyelevel upconversion stoplight for vehicles
US4935722A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 6, 1989 |
| Grant date | Jun 19, 1990 |
| Priority date | — |
| Expiry date | Nov 6, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60Q1/302
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A transparent eyelevel stoplight for vehicles is disclosed, which operates on an upconversion principle wherein red light in an otherwise transparent crystal is excited by invisible infrared radiation. The crystal may take the form of a transparent plate or an optical fiber applied to the vehicle rear window. The host crystal material is doped with a suitable rare-earth ion, which when illuminated by infrared energy produces visible light. An infrared laser may be used to illuminate the doped crystal, and is activated by the vehicle brakes. The crystal material is transparent to ordinary visible light and therefore will not obscure the driver's vision.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.