Honeywell targets Lumileds, Cree with LED patent lawsuit
Honeywell has a patent relating to the use of a reflector to recycle photons in a phosphor-converted LED. And it has identified the biggest LED makers in the US as alleged infringers.
The patent entitled "Efficient solid-state light emitting device with excited phosphors for producing a visible light output" was filed on December 22, 1998, and was issued on April 16, 2002. The patent was assigned to Honeywell by inventors Burgess Johnson and Wei Yang.
The lawsuit was filed in the Eastern District of Texas (see Southeast Texas Record). Honeywell is seeking a permanent injunction, damages adequate to compensate for the infringement in an amount to be proven at trial, treble damages, interest, fees, costs and other relief the court deems just.
The patent describes a solid-state light-emitting device producing visible light by emission from a phosphor layer. A reflector directs some of the light output back into the phosphor layer, enabling further excitation of and emission from the phosphor layer. The result is a more efficient device.
One application is an AlGaN-based LED with a phosphor layer and an adjacent metal reflector layer. Light from the LED that passes through the phosphor layer without causing excitation/emission is reflected back into the phosphor.