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US5650094A
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Red emitting long decay phosphors
Assignee: Nichia Chemical Industries Ltd
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Filing: 1995-06-06
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Granted: 1997-07-22
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Expires: 2015-06-06
Abstract
Abstract Long decay phosphors are disclosed that are comprised of rare-earth activated divalent titanates. In particular, the long decay phosphors are comprised of (Ca.sub.(1-a-b) Pr.sub.a M.sub.b)O.TiO.sub.2 wherein 0.00001≦a≦0.1 and 0.0≦b≦0.3 and M is Zn and/or Mg.
Inventors
- 👤 Martin R. Royce
- 👤 Shinya Matsuda
- 👤 Hiroto Tamaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:34
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7701; C09K11/7702; C09K11/7703
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
36 words
A red emitting long decay phosphor comprising a composition of (Ca.sub.(1-a-b) Pr.sub.a M.sub.b)O.TiO.sub.2 wherein 0.00001≦a≦0.1 and 0.0005≦b≦0.3 and M is a divalent metal element selected from the group consisting of Zn, Mg and a combination thereof.
Claim 2
Dependent Claim
36 words
A red emitting long decay phosphor comprising a composition of (Ca.sub.(1-a-b) Pr.sub.a M.sub.b)O.TiO.sub.2 wherein 0.00001≦a≦0.1 and 0.0005≦b≦0.3 and M is a divalent metal element selected from the group consisting of Zn, Mg and a combination thereof.
Claim 3
Dependent Claim
11 words
The long decay phosphor of claim 1 wherein M is zinc.
Claim 4
Dependent Claim
11 words
The long decay phosphor of claim 1 wherein M is magnesium.
Claim 5
Dependent Claim
16 words
The long decay phosphor of claim 1 wherein M is a combination of Zn and Mg.
Claim 6
Dependent Claim
9 words
The long decay phosphor of claim 1 wherein 0.000≦a≦0.01.
Claim 7
Dependent Claim
9 words
The long decay phosphor of claim 1 wherein 0.0005≦b≦0.2.
Claim 8
Dependent Claim
14 words
The long decay phosphor of claim 1 wherein said composition is: (Ca.sub.0.9 Pr.sub.0.001 Zn.sub.0.099)O.TiO.sub.2.
Claim 9
Dependent Claim
15 words
The long decay phosphor of claim 1 wherein said composition is: (Ca.sub.0.9 Pr.sub.0.001 Mg.sub.0.099)O.TiO.sub.2. 9.
Claim 10
Dependent Claim
20 words
The long decay phosphor of claim 1 wherein said composition is: (Ca.sub.0.9 Pr.sub.0.001 M.sub.0.009)O.TiO.sub.2, wherein M is Mg or Zn.
Claim 11
Independent Claim
103 words
A method of preparing a red emitting long decay phosphor comprising: preparing a mixture comprising a component comprising calcium, a component comprising praseodymium, and a component comprising titanium and firing the mixture to produce a long decay phosphor having the composition (Ca.sub.(1-a) Pr.sub.a)O.TiO.sub.2 wherein 0.00001≦a≦0.1 and wherein the firing step is carried out in a 2-step process comprising (a) firing under reducing conditions for 1-8 hours at a temperature of about 1100° to about 1400° C. to produce a fired product and (b) re-firing said fired product under oxidizing conditions for 1-4 hours at a temperature of about 700° to about 1300° C.
Claim 12
Independent Claim
103 words
A method of preparing a red emitting long decay phosphor comprising: preparing a mixture comprising a component comprising calcium, a component comprising praseodymium, and a component comprising titanium and firing the mixture to produce a long decay phosphor having the composition (Ca.sub.(1-a) Pr.sub.a)O.TiO.sub.2 wherein 0.00001≦a≦0.1 and wherein the firing step is carried out in a 2-step process comprising (a) firing under reducing conditions for 1-8 hours at a temperature of about 1100° to about 1400° C. to produce a fired product and (b) re-firing said fired product under oxidizing conditions for 1-4 hours at a temperature of about 700° to about 1300° C.
Claim 13
Dependent Claim
29 words
The method according to claim 10 wherein the long decay phosphor is capable of producing visually perceptible phosphorescence for at least 10 minutes after removal of an excitation source.
Claim 14
Dependent Claim
17 words
The method according to claim 11 wherein the excitation source produces UV radiation at about 365 nm.
Claim 15
Dependent Claim
68 words
The method according to claim 10 wherein the mixture includes a raw material selected from the group consisting of a component comprising Zn, a component comprising Mg and a combination of components thereof so as to produce a long decay phosphor having the composition: (Ca.sub.(1-a-b) Pr.sub.a M.sub.b)O.TiO.sub.2 wherein 0.0005≦b≦0.3 and M is a divalent metal element selected from the group consisting of Zn, Mg and a combination thereof.
Claim 16
Dependent Claim
19 words
The method according to claim 10 wherein said firing step is carried out in the presence of a flux.
Claim 17
Dependent Claim
15 words
The method according to claim 14 wherein said flux comprises boric acid or boric oxide.
Claim 18
Dependent Claim
33 words
The method according to claim 15 wherein said boric acid or boric oxide is present in an amount corresponding to 3-10 mole % as compared to the total amount of calcium titanate produced.
Claim 19
Dependent Claim
12 words
The method according to claim 14 wherein said flux comprises calcium fluoride.
Claim 20
Dependent Claim
30 words
The method according to claim 17 wherein said calcium fluoride is present in an amount corresponding to 3-10 mole % as compared to the total amount of calcium titanate produced.
Claim 21
Dependent Claim
12 words
The method according to claim 14 wherein said flux comprises ammonium tetrafluoroborate.
Claim 22
Dependent Claim
30 words
The method according to claim 19 wherein said ammonium tetrafluoroborate is present in an amount corresponding to 3-10 mole % as compared to the total amount of calcium titanate produced.
Claim 23
Dependent Claim
23 words
The method according to claim 10 wherein the firing step under reducing conditions is carried out at a temperature of about 1350° C.
Claim 24
Dependent Claim
23 words
The method according to claim 10 wherein the firing step under oxidizing conditions is carried out at a temperature of about 1000° C.
Claim 25
Dependent Claim
22 words
The method according to claim 10 wherein the firing step under reducing conditions is carried out in the presence of activated carbon.
Claim 26
Dependent Claim
13 words
The method according to claim 10 wherein said component comprising titanium comprises anatase.
Claim 27
Dependent Claim
13 words
The method according to claim 10 wherein said component comprising titanium comprises rutile.
Claim 28
Independent Claim
79 words
A method for producing long decay red phosphorescence comprising: (a) preparing a long decay phosphor having the composition (Ca.sub.(1-a-b) Pr.sub.a M.sub.b)O.TiO.sub.2, wherein 0.00001≦a≦0.1 and 0.0005≦b≦0.3, and M is a divalent metal element selected from the group consisting of Zn, Mg and a combination thereof; and (b) exciting said long decay phosphor with an excitation source so as to cause said long decay phosphor to produce visually perceptible phosphorescence for at least 10 minutes after removal of the excitation source.
Claim 29
Independent Claim
79 words
A method for producing long decay red phosphorescence comprising: (a) preparing a long decay phosphor having the composition (Ca.sub.(1-a-b) Pr.sub.a M.sub.b)O.TiO.sub.2, wherein 0.00001≦a≦0.1 and 0.0005≦b≦0.3, and M is a divalent metal element selected from the group consisting of Zn, Mg and a combination thereof; and (b) exciting said long decay phosphor with an excitation source so as to cause said long decay phosphor to produce visually perceptible phosphorescence for at least 10 minutes after removal of the excitation source.
Claim 30
Dependent Claim
17 words
The method according to claim 26 wherein said excitation source produces UV radiation at about 365 nm.
Claim 31
Independent Claim
90 words
A method of preparing a red emitting long decay phosphor comprising: preparing a mixture comprising a component comprising calcium, a component comprising praseodymium, a component comprising titanium and a raw material selected from the group consisting of a component comprising Zn, a component comprising Mg and a combination of components thereof and firing the mixture to produce a long decay phosphor having the composition (Ca.sub.(1-a-b) Pr.sub.a M.sub.b)O.TiO.sub.2 wherein 0.00001≦a≦0.1 and 0.0005≦b≦0.3 and M is a divalent metal element selected from the group consisting of Zn, Mg and a combination thereof.
Claim 32
Independent Claim
90 words
A method of preparing a red emitting long decay phosphor comprising: preparing a mixture comprising a component comprising calcium, a component comprising praseodymium, a component comprising titanium and a raw material selected from the group consisting of a component comprising Zn, a component comprising Mg and a combination of components thereof and firing the mixture to produce a long decay phosphor having the composition (Ca.sub.(1-a-b) Pr.sub.a M.sub.b)O.TiO.sub.2 wherein 0.00001≦a≦0.1 and 0.0005≦b≦0.3 and M is a divalent metal element selected from the group consisting of Zn, Mg and a combination thereof.
Claim 33
Dependent Claim
29 words
The method according to claim 20 wherein the long decay phosphor is capable of producing visually perceptible phosphorescence for at least 10 minutes after removal of an excitation source.
Claim 34
Dependent Claim
17 words
The method according to claim 29 wherein the excitation source produces UV radiation at about 365 nm.
Claim 35
Dependent Claim
19 words
The method according to claim 28 wherein said firing step is carried out in the presence of a flux.
Claim 36
Dependent Claim
15 words
The method according to claim 31 wherein said flux comprises boric acid or boric oxide.
Claim 37
Dependent Claim
33 words
The method according to claim 32 wherein said boric acid or boric oxide is present in an amount corresponding to 3-10 mole % as compared to the total amount of calcium titanate produced.
Claim 38
Dependent Claim
12 words
The method according to claim 31 wherein said flux comprises calcium fluoride.
Claim 39
Dependent Claim
29 words
The method according to claim 34 wherein said calcium fluoride is present in an amount corresponding to 3-10 mole as compared to the total amount of calcium titanate produced.
Claim 40
Dependent Claim
12 words
The method according to claim 31 wherein said flux comprises ammonium tetrafluoroborate.
Claim 41
Dependent Claim
30 words
The method according to claim 36 wherein said ammonium tetrafluoroborate is present in an amount corresponding to 3-10 mole % as compared to the total amount of calcium titanate produced.
Claim 42
Dependent Claim
63 words
The method according to claim 28 wherein the firing step is carried out in a 2-step process comprising (a) firing under reducing conditions for 1-8 hours at a temperature of about 1100° to about 1400° C. to produce a fired product and (b) re-firing said fired product under oxidizing conditions for 1-4 hours at a temperature of about 700° to about 1300° C.
Claim 43
Dependent Claim
23 words
The method according to claim 38 wherein the firing step under reducing conditions is carried out at a temperature of about 1350° C.
Claim 44
Dependent Claim
23 words
The method according to claim 38 wherein the firing step under oxidizing conditions is carried out at a temperature of about 1000° C.
Claim 45
Dependent Claim
22 words
The method according to claim 38 wherein the firing step under reducing conditions is carried out in the presence of activated carbon.
Claim 46
Dependent Claim
13 words
The method according to claim 28 wherein said component comprising titanium comprises anatase.
Claim 47
Dependent Claim
13 words
The method according to claim 28 wherein said component comprising titanium comprises rutile.
References Cited (Backward Citations)
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