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US 5,351,319 AGranted
Ferrofluid switch for a light pipe
AssigneeFord Motor Company
InventorsJohn M. Ginder, Jeffrey T. Remillard, Willes H. Weber
Life of this patent
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AssigneeFord Motor Company
InventorsJohn M. Ginder, Jeffrey T. Remillard, Willes H. Weber
Estimating the term…
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.
A device for modulating light output of a light pipe comprising:
The device as recited in 4 wherein said first coil is located adjacent to the portion of said light pipe having cladding removed.
The device as recited in 12 wherein said ferrofluid comprises hydrocarbon base.
A method for controlling the light output of a light pipe having a first index of refraction, fluid responsive to a magnetic field having a second index of refraction, a non-magnetic fluid immiscible in said magnetic fluid, retaining means concentrically located around at least a portion of said light pipe for retaining said fluids such that said magnetic fluid is capable of assuming two configurations, one adjacent to said light pipe and one separate from said light pipe and a controllable magnetic field means for causing said magnetically responsive fluid to assume one of said configurations, comprising the step of:
Dependencies are inferred from the claim text.