Osram Sylvania Inc.

Global Tungsten & Powders Corp.

Chen-Wen Fan

Dale E Benjamin

Richard G W Gingerich

Thomas M Snyder

Eric A Thomason

Tuan A Dang

David C Sheppeck

Frank A Schwab

Joan M Coveleskie

Charles F Chenot

Richard G Gingerich

Kenneth T Reilly

Gregory A Marking

Shellie K Northrop

Chung-nin Chau

Xianzhong Chen

Keith A Klindinst

Franz Kummer

Thomas Snyder

An electroluminescent phosphor comprising ZnS:Mn is disclosed. Also disclosed are ZnS:Mn electroluminescent phosphors that are free of or substantially free of copper, and/or wherein the phosphor has a D50 size of less than about 5 &#x3bc;m. In addition, a method for preparing a ZnS:Mn phosphor is disclosed, comprising the steps of contacting at least a portion of each of a first solution comprising a Zncompound, a manganese source, and a second solution comprising a Ssource agent; and then heating the mixture at a temperature and for a time sufficient to form a phosphor.

Electroluminescent ZnS:Mn phosphor and method of making

An electroluminescent (EL) phosphor is described wherein each individual phosphor particle is encapsulated in an inorganic coating, preferably aluminum oxyhydroxide. The encapsulated phosphor shows an extreme insensitivity to atmospheric moisture and suffers only minor loss of initial brightness in lamps. The method of applying the coating is a hybrid process, which involves EL phosphor particles first being coated with a thin inorganic film using an atomic layer deposition (ALD) method in a fluidized bed wherein the precursors are introduced sequentially in repeated cycles, subsequently followed by an additional coating layer applied by a chemical vapor deposition (CVD) method in which the precursors are introduced simultaneously.

Moisture resistant electroluminescent phosphor with high initial brightness and method of making

A method of producing a UV-emitting magnesium pentaborate phosphor is described. The method comprises combining a hydrated magnesium hexaborate with oxides of Y, Gd, Ce and Pr to form a mixture and firing the mixture in a slightly reducing atmosphere to form the phosphor. The hydrated magnesium hexaborate, which is preferably prepared as a precipitate, preferably has a formula MgBO.XHO where X is from 4 to 6.

Method of producing UV-emitting magnesium pentaborate phosphors

The present invention is an electroluminescent phosphor wherein each individual phosphor particle is encapsulated in an inorganic coating applied by an atomic layer deposition (ALD) coating method. In a preferred embodiment, the coating is aluminum oxyhydroxide. The encapsulated phosphor shows an extreme insensitivity to atmospheric moisture and suffers only minor loss of initial brightness in lamps.

Moisture-resistant electroluminescent phosphor with high initial brightness and method of making

A UV-emitting phosphor comprising SrBO:Eu phosphor particles that have been treated to yield a surface layer containing from greater than 0 to about 25 atomic percent aluminum. The holdover stability of the treated SrBO:Eu phosphor improves the 100-hour maintenance in a fluorescent tanning lamp to the extent that the treated phosphor may be subject to a holdover period of more than 25 days without a significant change in its 100-hour maintenance.

UV-emitting strontium borate phosphor with improved holdover stability

A method is provided for making narrow-band, UVB-emitting, (Y,Gd,Ce,Pr)Mg borate phosphors. The method involves the use of a mixed oxide co-precipitate which is combined with MgO and boric acid and fired twice to form the borate phosphor. The mixed oxide co-precipitate is formed by dissolving sources of Y, Gd, Ce, and optionally Pr, in an acid solution. Oxalic acid or ammonia is added to the solution (or vice versa) to form a co-precipitate of oxalates or hydroxides that are further fired to obtain a mixed oxide co-precipitate. The use of the mixed oxide co-precipitate improves homogeneity and yields a phosphor having a higher brightness with very little or no sticking between the fired cakes and the firing crucibles.

Method of making narrow-band UVB-emitting phosphors

The present invention is a single-component, UV-emitting phosphor having a composition represented by the general formula (YLaGdCe)POwhere x has a value in a range from 0.001 to 0.98, y has a value in a range from 0 and 0.1, z has a value in a range from 0.01 and 0.2, and x+y+z&#x3c;1. The phosphor when stimulated by 254 nm radiation emits in both the UVA and UVB regions. The relative balance of the UVA and UVB emissions may be varied by adjusting the relative amounts of Y and La. Brightness can be increased by adding Gd to the composition.

Single-component, UV-emitting phosphor

A narrow-band UVB emitting phosphor is described wherein the phosphor has a preferred composition represented by the general formula (YGdCePr)MgBOwhere x has a value in a range from 0.02 to 0.80, y has a value in a range from 0.01 to 0.97, and z has a value in a range from greater than 0 to 0.05 and x+y+z&#x3c;1. The phosphor has a narrow emission centered at about 312 nm when excited by radiation from a low-pressure mercury discharge.

Narrow-band UVB-emitting phosphor

A process for preparing particles of zinc sulfide-based electroluminescent phosphor having a moisture resistant coating thereon which comprises the steps of selecting a reaction vessel having a given height and a porous disc at the bottom thereof; charging the reaction vessel with phosphor particles and fluidizing the particles by introducing an inert gas into the vessel through the porous disc; heating the reaction vessel to a reaction temperature; introducing a coating precursor into the reaction vessel at a position adjacent the bottom of the vessel but above the disc; introducing a co-reactant into the reaction vessel at a position substantially mid-way of the given height; and maintaining the inert gas flow, the precursor flow and the co-reactant flow for a time sufficient for a reaction to occur and coat the phosphor with the moisture resistant coating. Apparatus for carrying out the process is also disclosed.

Method and apparatus for coating electroluminescent phosphors

A process for making an electroluminescent phosphor having a given emission spectra A, comprises the steps of manufacturing a beginning electroluminescent phosphor having an emission spectra B, different than A. A coating is applied to the phosphor having the emission spectra B to increase the resistance of the phosphor to the deleterious effects of moisture and change the emission spectra of the phosphor to emission spectra A. The application of the coating includes the steps of reacting a coating precursor with a mixture of oxygen and ozone.

Encapsulated long life electroluminescent phosphor

A long-life, white-emitting phosphor blend is provided which comprises about 75 wt. % of a first electroluminescent phosphor having an x color coordinate of about 0.530 and a y color coordinate of about 0.455; about 10 wt. % of a second electroluminescent phosphor having an x color coordinate of about 0.185 and a y color coordinate of about 0.440, said second electroluminescent phosphor containing about 600 ppm copper; and about 15 wt. % of a third electroluminescent phosphor having an x color coordinate of about 0.160 and a y color coordinate of about 0.175, said third electroluminescent phosphor containing about 300 ppm copper.

Long life, white light emitting electroluminescent phosphor

A method of coating phosphor particles comprises introducing an inert gas into a reaction vessel and charging phosphor particles into the reaction vessel. The reaction vessel is then heated to a reaction temperature and a coating precursor is introduced while the temperature is maintained for a time sufficient to saturate the phosphor particles with the precursor. Thereafter, continuous precursor is introduced into the reaction vessel, along with an oxygen/ozone mixture. The inert gas flow, oxygen/ozone mixture flow and further precursor are supplied for a time sufficient to coat the phosphor particles.

Method for making long-life electroluminescent phosphor

A method of recovering a base phosphor from encapsulated phosphors, which comprises the steps of selecting a recovery vessel including a magnetic stir bar; adding to the recovery vessel, deionized water, a first batch of concentrated hydrochloric acid and encapsulated phosphor to form a stirred suspension; heating the stirred suspension to about 90&deg; C. for about 2 hours; settling the stirred suspension; decanting the mother liquor and slurrying the remaining solids with a second batch of hydrochloric acid and water; decanting and washing the remaining solids with deionized water; filtering the remaining solids to form a filter cake; heating the filter cake at 110&deg; C. in air for a time sufficient to form a dried filter cake; and screening the dried filter cake through a &minus;325 mesh screen to yield a recovered base phosphor.

Recovery of electroluminescsent phosphor from encapsulated material

A method of coating phosphor particles by chemical vapor deposition. The phosphors are coated by introducing an inert gas into a reaction vessel; charging phosphor particles into the reaction vessel; heating the reaction vessel to a reaction temperature; introducing a coating precursor which includes carbon into the reaction vessel for a time sufficient to saturate the phosphor particles with the precursor; continuing precursor flow into the reaction vessel; introducing an oxygen/ozone mixture into the reaction vessel, the oxygen/ozone mixture comprising less than 4.4 wt. % ozone; and maintaining the inert gas flow, oxygen/ozone mixture flow and further precursor supply for a time sufficient to coat the phosphor particles. The process produces phosphors having from 2200 to 6300 ppm of carbon on the coating and provides lamp efficacy's of greater than 6.1 lm/watt.

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Sayre, PA, United States of America

Chen-Wen Fan