Osram Sylvania Inc.

Gregory A Marking

Thomas M Snyder

Vaddi B Reddy

Chung-nin Chau

Chen Wen Fan

Thomas M Synder

Kenneth T Reilly

Chen-Wen Fan

Shellie K Northrop

Courtney Spencer Warren

Brian J Payne

Eric R Mercer

Chad E DeForest

James E Murphy

Thomas Snyder

There is provided a method of making a SrBO:Pb phosphor that increases the manufactured quantity of the SrBO:Pb phosphor by approximately seven fold when using the same size reaction vessel, decreases the lead-containing waste stream, and eliminates the use of hazardous concentrated ammonium hydroxide. The UV emission brightness is equivalent to or better than the same phosphor when prepared using prior methods.

Method of making a lead-activated strontium hexaborate phosphor

There is described a method for the preparation of a green-emitting terbium and cerium co-activated gadolinium magnesium pentaborate phosphor that utilizes a hydrated magnesium hexaborate as a boron source. The hydrated magnesium hexaborate preferably may be represented by the formula MgBO.XHO where X is from 4 to 6, preferably 4.8 to 5.5, and more preferably about 5. The hydrated magnesium hexaborate is combined with oxides of Gd, Ce, and Tb, and at least one magnesium compound selected from MgCl, MgF, and MgO, and then fired in a slightly reducing atmosphere to form the phosphor. The method results in a greater homogeneity of the fired cake and subsequently a higher brightness. In addition, the method preferably requires only one firing step and provides very little or no sticking of the fired cake to the firing boats.

Method of making green-emitting borate phosphors

There is described a method of producing a red-emitting manganese and cerium co-activated gadolinium magnesium zinc pentaborate phosphor that comprises combining a hydrated hexaborate of zinc, magnesium, and manganese with oxides of Gd and Ce to form a mixture, and firing the mixture in a slightly reducing atmosphere to form the phosphor. Preferably, the hydrated hexaborate has an approximate composition represented by (Zn,Mg,Mn)BO.XHO, where X is 5.3 to 6.2.

Method of making red-emitting borate phosphor

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

Blue-emitting phosphors for use with plasma display panels (PDP) or other vacuum ultraviolet-excited (VUV) devices are provided. These blue-emitting phosphors and mixtures thereof include at least a europium-activated calcium-substituted barium hexa-aluminate (CBAL) phosphor. Preferably, the CBAL phosphor has a composition which may be represented by the formula: BaCaEuAlO, wherein 0&#x3c;x&#x3c;0.25 and 0.01&#x3c;y&#x3c;0.20. These blue-emitting phosphors exhibit improved degradation characteristics, including reduced color shift and increased intensity maintenance, under conditions found in VUV-excited devices.

VUV-excited device with blue-emitting phosphor

The sensitivity of YPO:Ce phosphors to 185 nm radiation may be increased by incorporating a praseodymium coactivator. The use of Ce and Pr as co-activators in a YPOphosphor improves the sensitivity of the phosphor to excitation by both 185 nm and 254 nm radiation and should increase total UVA and UVB output in fluorescent lamps. The co-activated phosphor has emission peaks at about 355 nm and about 335 nm.

Ce,Pr-coactivated yttrium phosphate phosphor and lamp containing same

A Sr(Al,Mg)O:Ce,Pr phosphor is described wherein the phosphor has an increased sensitivity to excitation by 185 nm radiation compared to a Sr(Al,Mg)O:Ce phosphor. The Ce,Pr-coativated strontium magnesium aluminate phosphor emits ultraviolet (UV) radiation at about 306 nm in the UVB region. Suntan lamps made with this phosphor exhibit improved performance over lamps made with a commercial Sr(Al,Mg)O:Ce phosphor.

Ce,Pr-coactivated strontium magnesium aluminate phosphor and lamp containing same

The UVC emission of a Sr(Al,Mg)O:Pr is improved by providing an excess of magnesium relative to the molar amount praseodymium In particular, the UVC-emitting phosphor has a composition represented by the formula SrPrAlMgOwherein y&#x3e;x. The phosphor is excited by vacuum ultraviolet radiation and may be used to create a mercury-free germicidal lamp.

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A UV-emitting phosphor is described wherein the phosphor is excitable by vacuum ultraviolet radiation (VUV). The phosphor is a gadolinium-activated strontium magnesium aluminate which preferably has an excitation maximum at about 172 nm. The phosphor exhibits a narrow-band UV emission at about 310 nm which makes it useful for medical phototherapy applications.

UV-emitting phosphor and lamp containing same

A UV-emitting, Ce,Pr-coactivated calcium pyrophosphate phosphor is provided wherein the Pr activator increases the phosphor's sensitivity to excitation by 185 nm radiation. The improved sensitivity to the 185 nm radiation allows the phosphor to make better use of the approximate 10% of the UV radiation that is emitted at 185 nm by a low pressure mercury discharge.

Ce,Pr-coactivated calcium pyrophosphate phosphor and lamp containing same

A UV-emitting phosphor and lamp containing same are described. The phosphor is a praseodymium-activated pyrophosphate-based phosphor which may be represented by the general formula (Ca,Sr)PO:Pr where 0&#x2266;x&#x2266;2. The phosphor is excitable by vacuum ultraviolet (VUV) radiation and in particular it may be excited by Xe-excimer discharges and thereby provide a Hg-free UV-emitting lamp. The phosphor exhibits a broad emission in the UVC region in the wavelength range from about 220 nm to about 280 nm with the peak emission occurring in the wavelength range from about 230 nm to about 240 nm. The emission characteristics of the phosphor may be varied depending on the ratio of Sr/Ca.

An acidic solution can be used to dissolve undesirable impurity phases in UV-emitting SrBO:Eu phosphors that reduce the UV emission intensity of said phosphor. In particular, the impurity phase, SrBO:Eu, is no longer detected after treating the phosphor with an acid washing process. The phosphors after acid washing are shown to have improved UV emission intensity without greatly increasing the mean particle size.

High brightness green-emitting phosphor

A ZnS:Ag,Al phosphor and method of making are described wherein the ZnS:Ag,Al phosphor exhibits a substantially polyhedral morphology and low particle agglomeration. The method of making includes the use of a mixed sodium chloride and alkaline-earth metal chloride flux. The resulting ZnS:Ag,Al phosphors may be made into finished CRT phosphors having improved CRT screen making properties.

ZnS:Ag,A1 phosphor and method of making same

A Li,SO,'Na,SO,mixed flux for use in the synthesis of yttrium tantalate x-ray phosphors has been invented. The phosphors made with the mixed flux exhibit a dramatic increase XOF brightness, decreased persistence, and a reduced particle size.

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Sayre, PA, United States of America

Gregory A Marking