Switchable lighting device and use thereof
US9881531B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 13, 2015 |
| Grant date | Jan 30, 2018 |
| Priority date | — |
| Expiry date | Mar 29, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2358/00
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A lighting device for operation in at least two operating modes: a mode for free viewing and a mode for restricted viewing. The device includes a backlighting system, which in the restricted-viewing mode radiates light in a restricted angular range, a plate-shaped optical element situated along a viewing direction in front of the backlighting system, and illuminants laterally arranged at the optical element. The optical element is configured as a light guide consisting of a matrix plastic and, homogeneously distributed therein, scattering particles of a polymer. The light guide is transparent to at least 80% of the light emitted by the backlighting system. The light laterally incident on the optical element from the illuminants is radiated in a free viewing range; in the restricted-viewing mode, the backlighting system is switched on and the illuminants switched off; in the free-viewing mode, the illuminants are on and the backlighting system is off.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.