Osram Sylvania Inc.

Global Tungsten & Powders Corp.

Other

Gte Products Corporation/gte Laboratories, Inc.

Dale E Benjamin

Chen-Wen Fan

Richard G W Gingerich

Tuan A Dang

Robin W Munn

David C Sheppeck

Frank A Schwab

Joan M Coveleskie

Charles F Chenot

Richard G Gingerich

A Gary Sigai

Kenneth T Reilly

Ricky D Morgan

Hans-Joachim Lunk

Silvia E Lichtensteiger

Henry J Stevens

Deborah V Lutz

Timothy A Frisk

Franz Kummer

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

The coating the tungsten powder particles with a ceramic barrier suppresses the leachability of tungsten in aqueous media. Preferably, the ceramic coating substantially encapsulates each particle of tungsten and has a thickness of at least about 30 nm and, more preferable, from about 200 nm to about 500 nm. Examples of ceramic coatings that may be used include, but are not limited to, aluminum oxide (alumina), aluminum oxyhydroxide (AlOOH), zirconium oxide (zirconia), cerium oxide (ceria), hafnium oxide (hafnia), and magnesium oxide (magnesia).

Ceramic-coated tungsten powder

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 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 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 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.

Method for making high-efficacy and long life electroluminescent phosphor

Method for making high-efficacy and long life electroluminescent phophor

A method of coating phosphor particles that comprises the steps of 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 into the reaction vessel; introducing an oxygen/ozone mixture into the reaction vessel; and maintaining the agitation, inert gas flow, oxygen/ozone mixture flow and precursor supply for a time sufficient to coat the phosphor particles. This process yields phosphors having a half-life of upwards of 3,100 hours with efficacys of greater than 6 lumens per watt (lm/w).

Method of making long life electroluminescent phosphor

A method for forming a continuous, conformal non-particulate coating of boron oxide on individual phosphor particles is provided. The method involves reacting a boron-containing precursor with an oxidizing gas in a fluidized bed of phosphor particles. The boron oxide coated phosphor exhibits an increased quantum efficiency under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation.

Boron oxide coated phosphor and method of making same

A method of forming a partial protective coating on phosphor particles to improve initial power output and maintenance of fluorescent lamps made with the phosphor. The phosphor particles are fluidized in a bed and at least partially enveloped by a coating precursor material. Residence time of the phosphor particles in the fluidized bed is short so that the phosphor particles are only partially coated with the coating precursor material. The coating precursor material is reacted to form a protective coating over at least a portion of the surface of the phosphor particles. The partially-coated phosphor particles are then annealed to cause the protective coating to selectively cover at least a portion of certain sites on the surface of the phosphor particles.

Method of forming a partial coating on phosphor particles by coating the

Disclosed is a method for adjustably controlling the rate of circulation and temperature gradient in a fluidized bed.

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Athens, PA, United States of America

Dale E Benjamin