Ferrofluid switch for a light pipe
US5351319A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 15, 1993 |
| Grant date | Sep 27, 1994 |
| Priority date | — |
| Expiry date | Nov 15, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/3572
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A ferrofluid controlled switch for a light pipe has a light pipe having a first index of refraction, a fluid responsive to a magnetic field having a second index of refraction, and an enclosure concentrically located around at least a portion of the light pipe for retaining the fluid such that the fluid is capable of assuming two configurations, one adjacent to the light pipe and one separate from the light pipe. A controllable magnetic field device such as a permanent magnet or wire coils are used to transfer the magnetically responsive fluid between said two configurations to reduce the output of the light pipe when the fluid is adjacent to the light pipe.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.