Sarnoff Corporation

Stanley Electric Co., Ltd

Lightscape Materials, Inc.

Diane Zaremba

Perry Niel Yocom

Yongchi Tian

Ian Gregory Hill

Perry Neil Yocom

The present invention provides a light emitting device comprising: a light output; a light source that produces light having a wavelengths of 530 nm or less; and a wavelength transformer located between the light source and the light output, where the wavelength transformer comprises SrCaGaS: yEu&#xb7;zGaS, where x is 0.0001 to 1, y is a value defining sufficient Euto provide luminescent emission, and z is 0.0001 to 0.2 based on the mole amount of SrCaGaS, and where the wavelength transformer effectively increases the light at the light output, the light having a wavelength between 535 nm and 560 nm.

Methods and devices using high efficiency alkaline earth metal thiogallate-based phosphors

Provided, among other things, is a strontium calcium thiogallate phosphor doped with divalent europium, and having the following formula:SrCaGaS:yEu.zGaS,where x is 0.0001 to 1, y is a value defining sufficient Euto provide luminescent emission, and z is 0.0001 to 0.2 based on the mole amount of SrCaGaS:yEu.

High efficiency alkaline earth metal thiogallate-based phosphors

Provided among other things is a method of forming a phosphor of the formulaSrGaS:Eu:xGaS&#x2003;&#x2003;(I)wherein x is 0.0001 to 0.2, wherein a minor part of the europium component may be substituted with praseodymium in an efficiency enhancing amount, and wherein the median grain size of the phosphor composition is from 2 to 12 microns, the method comprising:

Efficient, size-selected green-emitting phosphors

A red-emitting strontium-calcium sulfide phosphor doped with europium and a halide. These phosphors are made by combining their insoluble sulfates, adding europium as an activator, firing in hydrogen sulfide to form the corresponding sulfides, adding a halide co-activator and firing in nitrogen. The resulting phosphors can be used with various electroluminescent devices to produce colored or white light.

Red photoluminescent phosphors

A method of forming high efficiency emission alkali metal activated gallium sulfide phosphors by including an excess of 1-7% of gallium. A solution of a soluble gallium salt is added to a sulfate precipitate of an alkali metal sulfate and firing in hydrogen sulfide atmosphere at temperatures up to about 900&deg; C.

Preparation of high emission efficiency alkaline earth metal thiogallate phosphors

Long persistence phosphors based on strontium sulfide and activated with a divalent rare earth such as europium and a trivalent rare earth that does not change valence in a strontium sulfide host, and including oxygen and a halide, have long persistence and emit in the red-to-orange colors of the spectrum.

Long persistence red phosphors and method of making

A long persistence, orange-red emitting phosphor has the formula AS:Eu Tr O X wherein A is an alkaline earth metal ion, Tr is one or more trivalent rare earth metal ions, X is a halide, m is an integer in the range 0.01 to 0.5 atomic percent, n is an integer in the range 0.3 to 0.5 atomic percent, x is an integer in the range 0.01 to 2.0 atomic percent, and y is an integer in the range 0.01 to 0.5 atomic percent. These phosphors are made by reacting an alkaline earth metal sulfate to form the corresponding sulfide, mixing with europium oxide and one or more trivalent rare earth metal oxides to dope the sulfate, mixing the doped alkaline earth metal sulfate with a hydrocarbon and powdered sulfur, heating to form the corresponding phosphor sulfide and mixing with a halide compound to form the corresponding oxyhalide sulfide phosphor. The persistence time of the phosphors can be improved by grinding the phosphor and refiring it in the presence of an ammonium halide.

Long persistence alkaline earth sulfide phosphors

Red and orange-red emitting long persistence phosphors based on strontium sulfide and activated with a divalent rare earth such as europium, can be made by heating in the presence of an ammonium halide, or a trivalent rare earth. Using ammonium halide as the flux, the red-emitting phosphor can be molded into a desired shape. Using ammonium halide and powdered alumina, the red-emitting phosphor can be made into a powder directly. Heating a rare earth activated (Eu) strontium sulfide in the presence of a trivalent rare earth salt in the presence of sulfur and a source of carbon, fine particle size red-emitting phosphor particles can be made.

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Fairless Hills, PA, United States of America

Diane Zaremba