Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
250 words
A process for producing a europium activated strontium tetraborate UV emitting phosphor, said process comprising: (a) adding SrCO 3 and Eu 2 O 3 to an aqueous solution of H 3 BO 3 which is at a temperature of at least about 70° C., to form a mixture wherein the mole ratio of SrCO 3 to H 3 BO 3 is from about 1:4 to about 1:4.5 and the Eu 2 O 3 content is from about 0.003 moles to about 0.015 moles; (b) digesting said mixture at a temperature of at least about 90° C. for a sufficient time to form a solid precipitate comprising a strontium borate hydrate intermediate having the formula SrB 6 O 10 .5H 2 O and a liquor; (c) separating said solid from said liquor; (d) drying said solid: and (e) firing the resulting dried solid in an atmosphere consisting essentially of from about 0.3% to about 3.0% by volume hydrogen and the balance nitrogen at a temperature of at least about 800° C. for a sufficient time to produce the final phosphor the major portion of which consists essentially of strontium tetraborate as a host material doped with europium ions substituted for strontium ions, said final phosphor having a composition in percent by weight 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, with said europium being relatively uniformly distributed throughout the balance of said phosphor.
Claim 2
Dependent Claim
250 words
A process for producing a europium activated strontium tetraborate UV emitting phosphor, said process comprising: (a) adding SrCO 3 and Eu 2 O 3 to an aqueous solution of H 3 BO 3 which is at a temperature of at least about 70° C., to form a mixture wherein the mole ratio of SrCO 3 to H 3 BO 3 is from about 1:4 to about 1:4.5 and the Eu 2 O 3 content is from about 0.003 moles to about 0.015 moles; (b) digesting said mixture at a temperature of at least about 90° C. for a sufficient time to form a solid precipitate comprising a strontium borate hydrate intermediate having the formula SrB 6 O 10 .5H 2 O and a liquor; (c) separating said solid from said liquor; (d) drying said solid: and (e) firing the resulting dried solid in an atmosphere consisting essentially of from about 0.3% to about 3.0% by volume hydrogen and the balance nitrogen at a temperature of at least about 800° C. for a sufficient time to produce the final phosphor the major portion of which consists essentially of strontium tetraborate as a host material doped with europium ions substituted for strontium ions, said final phosphor having a composition in percent by weight 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, with said europium being relatively uniformly distributed throughout the balance of said phosphor.
Claim 3
Dependent Claim
27 words
A process of claim 1 wherein the mole ratio of H 3 BO 3 to water in said aqueous solution is from about 1:2.6 to about 1:4.10.
Claim 4
Dependent Claim
25 words
A process of claim 1 wherein the temperature of said aqueous H 3 BO 3 solution is from about 70° C. to about 80° C.
Claim 5
Dependent Claim
19 words
A process of claim 1 wherein said mole ratio of SrCO 3 to H 3 BO 3 is 1:4.28.
Claim 6
Dependent Claim
24 words
A process of claim 1 wherein the Eu 2 O 3 content in said mixture is from about 0.009 moles to about 0.01 moles.
Claim 7
Dependent Claim
31 words
A process of claim 1 wherein said mixture is digested at a temperature of from about 90° C. to about 100° C. for from about 5 hours to about 8 hours.
Claim 8
Dependent Claim
32 words
A process of claim 1 wherein said dried solid is fired at a temperature of from about 890° C. to about 960° C. for from about 6 hours to about 24 hours.
Claim 9
Dependent Claim
31 words
A process of claim 7 wherein said mixture is fired at a temperature of from about 910° C. to about 920° C. for from about 6 hours to about 10 hours.
Claim 10
Dependent Claim
25 words
A process of claim 1 wherein the firing is done in an atmosphere consisting essentially of about 1% by volume hydrogen and the balance nitrogen.
Claim 11
Dependent Claim
39 words
A process of claim 1 wherein the weight composition of said final phosphor is from about 35.17% to about 35.18% strontium, from about 17.71% to about 17.72% boron, from about 1.18% to about 1.25% boron, and the balance oxygen.