Gte Products Corporation

Osram Sylvania Inc.

Gte Sylvania Incorporated

Gte Laboratories Incorporated

Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh

Fred R. Taubner

Henry B. Minnier

Charles F. Chenot

A. Gary Sigai

Charles F Chenot

Anthony F Kasenga

Leslie F Gray

Wolfgang Walter

Michael A Krebs

Richard G Gingerich

James E Mathers

Chung N Chau

Francis N Shaffer

Henry B Minnier

Anthony L Diaz

Ulrich Mueller

Martin Zachau

A Gary Sigai

Chen-Wen Fan

Romano G Pappalardo

Dale E Benjamin

Robin W Munn

Fred R Taubner

Judy A Belinski-Wolfe

Dieter Schmidt

Doris L Brown

Deborah V Lutz

Shelley A Sonner

Leslie F Trudeau

Franz Kummer

Fuquiang Huang

Donald R Castle

Vincent Chiola, Executrix

Robert E Taylor, Deceased

A method of making zinc sulfide based electroluminescent phosphors is described wherein a first-fired zinc sulfide material having a hexagonal &#x3b2;-ZnS crystal structure is at least partially converted to a distorted hexagonal &#x3b2;-ZnS crystal structure by ultrasonic irradiation. The first-fired material is then fired at a lower temperature to form an electroluminescent phosphor.

Method of making electroluminescent phosphor using sonochemistry

A novel phosphate treated silicate phosphor has been invented that exhibits improved lumen maintenance with respect to the untreated phosphor when used in a fluorescent lamp. In one aspect, a protective phosphate-containing surface layer is formed by treating the phosphor in an aqueous phosphate solution, filtering, and annealing. In particular, a BaSi,O,:Pb phosphor that has been treated in this way exhibits improved maintenance in a fluorescent lamp and a characteristic X-ray diffraction pattern evidencing the presence of the protective phosphate-containing surface layer.

Phosphate treated silicate phosphor

A cation-treated silicate phosphor and fluorescent lamp made therefrom are provided wherein the 100 hour radiance maintenance is significantly improved. The cation treatment method involves adding an amount of a silicate phosphor to a salt solution containing a cation wherein the ratio of cation to phosphor in the solution is from about 1:2 to about 4:1 moles of cation to moles of phosphor. The solution is then stirred for a time sufficient to cause the cation to attach to the phosphor surface to form a cation-treated phosphor. The cation-treated phosphor is separated from the solution and annealed at a temperature and for a time sufficient to increase radiance maintenance of the cation-treated phosphor.

Cation-treated silicate phosphor

A barium magnesium aluminate phosphor having improved maintenance and efficiency is provided. The novel phosphor is suitable for use in conventional fluorescent lamp applications and applications utilizing VUV excitation, including Xe excimer lamps and plasma display panels.

Barium magnesium aluminate 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 fine, largely beta phase calcium pyrophosphate powder for, e.g., a diffuser coating for the interior surface of lamp envelopes. The powder is useful for electrostatic deposition of such coatings under varying conditions of environmental humidity. A process for the synthesis of the calcium pyrophosphate is also disclosed. Dibasic calcium orthophosphate (monetite) is dissolved in a dilute aqueous hydrochloric acid solution and spray-dried to form a calcium phosphate powder of spherically shaped hollow particles. The calcium phosphate powder is fired in air to convert the calcium phosphate powder to a spherical calcium pyrophosphate powder including the beta phase as a major component and the gamma phase as a minor component. For a diffuser coating, the poder is sonicated to fragment a portion of the hollow particles.

Synthesis of beta phase spherical calcium pyrophosphate powder

A method for preparing a specific zinc orthosilicate phosphor particle having a nonparticulate, conformal aluminum oxide coating wherein all of a manganese activator is present as manganese (II) and occupies zinc (II) sites includes the steps of blending a zinc source, a manganese (II) source, a silicon source, and a tungsten source in amounts in accordance with said formula with an amount of up to about 2 weight percent NH.sub.4 Cl and up to about 0.2 weight percent NH.sub.4 F to form a relatively uniform admixture, firing the mixture in a closed container under an inert non-oxidizing atmosphere to promote retention of manganese in the plus two valance state whereby oxidation of manganese to a higher valence state is avoided and conditions promote larger particle size formation; milling and washing the phosphor in an aqueous citric acid solution to remove unreacted manganese; rinsing, drying and sieving the dried phosphor; and depositing a continuous, nonparticulate, conformal aluminum oxide coating on the dried phosphor particle.

Method for preparing zinc orthosilicate phosphor particle

A manganese-activated zinc orthosilicate phosphor having the empirical formula:

Method for preparing zinc orthosilicate phosphor

A method of making a lanthanum cerium terbium phosphate phosphor involves the single-step reaction of single-phase, mixed valence state lanthanum cerium terbium oxide with boron phosphate in the presence of a flux-forming compound containing lithium. The resulting phosphor is up to 5% brighter than the same phosphor prepared without the lithium-containing compound.

Method of making lanthanum cerium terbium phosphate phosphor with

A method of making a lanthanum cerium terbium phosphate phosphor involves the single-step reaction of a single-phase, mixed valence state lanthanum cerium terbium oxide and boron phosphate. Alternatively, the single-step reaction may involve a mixture of lanthanum oxide, cerium oxide, terbium oxide and boron phosphate.

Method of making lanthanum cerium terbium phosphate phosphor

A europium activated strontium tetraborate UV emitting phosphor is disclosed having a weight composition of from about 34.72% to about 35.80 strontium %, from about 17.66% to about 17.78 boron %, from about 0.37% to about 1.86% europium, and the balance oxygen. The phosphor has essentially elongated prism-like particles with the europium relatively uniformly distributed throughout the balance of the phosphor and with the particle size distribution being characterized by the 50% size being in the range of from about 7 micrometers to about 12 micrometers as determined by Coulter Counter measurement and with less than about 12% by weight of the particles having a particle size of greater than about 16 micrometers as determined by Coulter Counter measurement. The process for making the phosphor is disclosed which involves forming a mixture of strontium carbonate and europium carbonate in an aqueous solution of boric acid at a temperature of at least about 70.degree. C. with the mole ratio of SrCO.sub.3 to H.sub.3 BO.sub.3 being from about 1:4 to 1:4.5 and the Eu.sub.2 O.sub.3 content being from about 0.003 to 0.015 moles. The mixture is digested at at least about 90.degree. C. for a sufficient time to form a solid precipitate comprising a strontium borate hydrate intermediate and a liquor, followed by separating the solid from the liquor, drying the solid and firing the solid in an atmosphere of 0.3%, to 3.0% by volume hydroen and the balance nitrogen at at least about 800.degree. C. for a sufficient time to produce the phosphor.

Europium activated strontium tetraborate UV phosphors

A process is disclosed for applying a lubricant to a powdered material to control the fluidity of the powdered material. In the process one first obtains at least x number of samples of the powdered material without lubricant. Thereafter, increasing amounts of lubricant are applied to x-1 number of the samples. The bulk and tap densities of the samples are then measured and the Hausner ratio from the densities is calculated. The Hausner ratio versus the concentration of the lubricant in the powder samples is plotted and the concentrations of the minima lubricant in the powder samples at the point of the plot obtained in step e are determined. The concentration of lubricant determined in step f is applied to the remainder of the powdered material whereby an operational level of fluidity of the powder is achieved.

Procedure for controlling powder fluidity

A europium activated strontium tetraborate UV emitting phosphor is disclosed having a weight composition of from about 34.72% to about 35.80 strontium %, from about 17.66% to about 17.78 boron %, from about 0.37% to about 1.86% europium, and the balance oxygen. The phosphor has essentially elongated prism-like particles with the europium relatively uniformly distributed throughout the balance of the phosphor and with the particle size distribution being characterized by the 50% size being in the range of from about 7 micrometers to about 12 micrometers as determined by Coulter Counter measurement and with less than about 12% by weight of the particles having a particle size of greater than about 16 micrometers as determined by Coulter Counter measurement. The process for making the phosphor is disclosed which involves forming a mixture of strontium oxide and europium carbonate in an aqueous solution of boric acid at a temperature of at least about 70.degree. C. with the mole ratio of SrCO.sub.3 to H.sub.3 BO.sub.3 being from about 1:4 to 1:4.5 and the Eu.sub.2 O.sub.3 content being from about 0.003 to 0.015 moles. The mixture is digested at at least about 90.degree. C. for a sufficient time to form a solid precipitate comprising a strontium borate hydrate intermediate and a liquor, followed by separating the solid from the liquor, drying the solid and firing the solid in an atmosphere of 0.3% to 3.0% by volume hydrogen and the balance nitrogen at at least about 800.degree. C. for a sufficient time to produce the phosphor.

Process for producing europium activated stronium tetraborate UV phosphor

Calcium fluorophosphate phosphor co-activated by specific levels of antimony and manganese emits in a narrow portion of the yellow region of the spectrum making such phosphor useful in fluorescent lamps. Furthermore, when blended in specific proportions with a blue-emitting divalent europium activated strontium halophosphate, and incorporated into a fluorescent lamp, the resultant lamp gives an increased lumen per watt output over a 'cool white' lamp incorporating a standard 'cool white' calcium halophosphate phosphor.

Lamp incorporating phosphor blend of calcium fluorophosphate and

A process is disclosed for producing a europium activated strontium borate phosphor having a strontium containing coating. The process involves washing a europium activated strontium borate phosphor with a solution of strontium hydroxide to produce a first washed phosphor followed by removing the first washed phosphor from the resulting wash solution. The first washed phosphor is washed with a wash solution selected from the group consisting of ammonium fluoride in alcohol, ammonium bifluoride in alcohol, and a strontium salt in ammonium hydroxide, followed by removing the resulting second washed phosphor from the resulting wash solution. The second washed phosphor is then heated to produce the coated phosphor.

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Towanda, PA, United States of America

Charles F Chenot