US5120619A
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US
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X-ray phosphors and X-ray intensifying screen using the phosphor
Assignee: Nichia Corp
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Filing: 1990-11-07
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Granted: 1992-06-09
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Expires: 2010-11-07
Abstract
Abstract This invention relates to rare earth tantalate and/or niobate phosphors which emit light under X-ray excitation, and an X-ray intensifing screen which utilizes these phosphors. The phosphor is represented by the general formula (I); .sup.Ln 1-x-(2/3)y-(1/3)z.sup.M" y.sup.M' z.sup.DO 4:xR.sup.3+(I) In this formula, M" is at least one kind of divalent metal selected from the group consisting of Be, Mg, Ca, Sr, Zn and Cd, M' is at least one kind of alkali metal selected from the group consisting of Li, Na, Ba and K, Ln is at least one kind of element selected from the group consisting of Y, Gd, La and Lu, D consists of Ta and/or Nb, and R is at least one selected from the group conssiting of Tm, Pr, Sm, Eu, Tb, Dy and Yb, y is a value in the range 1×10 -5 ≦y≦1, z is a value in range 1×10 -4 ≦z≦0.1, and x is a numerical value in the range 0≦×≦0.05. The X-ray intensifying screen is composed of a supporting plane coated with the above mentioned phosphor. The phosphor is distributed on, and held in place by mixing with a binding agent.
Inventors
- 👤 Shigeharu Nakajima
- 👤 Genichi Shinomiya
- 👤 Mizuho Takeda
- 👤 Satoru Chikutei
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:24
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7701; C09K11/7703; C09K11/7702; C09K11/7766; C09K11/7767; C09K11/7768; C09K11/7769; C09K11/7783; C09K11/7784; C09K11/7785; C09K11/7786
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
299 words
An X-ray intensifying screen comprising: a support; and a phosphor layer supported on said support, said phosphor layer comprising a phosphor which emits light by the excitation of X-rays, having a composition represented by the formula: Ln.sub.1-x-(2/3)y-(1/3)z M".sub.y M'.sub.z DO.sub.4 :xR.sup.3+ where: M" is at least one element selected from the group consisting of Ca, Sr and Cd, M' is at least one alkali metal selected from the group consisting of Li, Na and K, Ln is at least one rare earth element selected from the group consisting of Y, La and Lu, D is Ta, or Ta and Nb, R is at least one activator metal selected from the group consisting of Tm, Ce, Pr, Sm, Eu, Tb, Dy and Yb, y is a value in the range of 1×10 -5 to 1, z is a value in the range of 1×10 -4 to 0.1, and x is a value in the range of 0 to 0.05, said phosphor being obtained by admixing an oxide of Ln in an amount corresponding to 1-x-(2/3)y-(1/3)z parts by mol of Ln, an oxide of D in an amount corresponding to one part by mol of D, an oxide of R in an amount corresponding to x parts by mol of R, a chloride of M' in an amount sufficient to provide z parts by mol of M' and a carbonate of M" in an amount corresponding by y parts by mol of M", the amount of chloride of M' being larger than z parts by mole of M' in said phosphor and firing the admixture at a temperature and for a time sufficient to provide said phosphor having said composition and wherein said phosphor exhibits a smaller afterglow and a greater brightness intensity than the same phosphor absent M" and M'.
Claim 2
Dependent Claim
299 words
An X-ray intensifying screen comprising: a support; and a phosphor layer supported on said support, said phosphor layer comprising a phosphor which emits light by the excitation of X-rays, having a composition represented by the formula: Ln.sub.1-x-(2/3)y-(1/3)z M".sub.y M'.sub.z DO.sub.4 :xR.sup.3+ where: M" is at least one element selected from the group consisting of Ca, Sr and Cd, M' is at least one alkali metal selected from the group consisting of Li, Na and K, Ln is at least one rare earth element selected from the group consisting of Y, La and Lu, D is Ta, or Ta and Nb, R is at least one activator metal selected from the group consisting of Tm, Ce, Pr, Sm, Eu, Tb, Dy and Yb, y is a value in the range of 1×10 -5 to 1, z is a value in the range of 1×10 -4 to 0.1, and x is a value in the range of 0 to 0.05, said phosphor being obtained by admixing an oxide of Ln in an amount corresponding to 1-x-(2/3)y-(1/3)z parts by mol of Ln, an oxide of D in an amount corresponding to one part by mol of D, an oxide of R in an amount corresponding to x parts by mol of R, a chloride of M' in an amount sufficient to provide z parts by mol of M' and a carbonate of M" in an amount corresponding by y parts by mol of M", the amount of chloride of M' being larger than z parts by mole of M' in said phosphor and firing the admixture at a temperature and for a time sufficient to provide said phosphor having said composition and wherein said phosphor exhibits a smaller afterglow and a greater brightness intensity than the same phosphor absent M" and M'.
Claim 3
Dependent Claim
13 words
The X-ray intensifying screen as claimed in claim 1, wherein R is Tm.
Claim 4
Dependent Claim
26 words
The X-ray intensifying screen as claimed in claim 1, wherein M" is Ca, and y is a value in the range 1×10 -5 ≦y≦3×10 -1 .
Claim 5
Dependent Claim
26 words
The X-ray intensifying screen as claimed in claim 1, wherein M" is Sr and y is a value in the range 1×10 -5 ≦y≦6×10 -1 .
Claim 6
Dependent Claim
12 words
The X-ray screen according to claim 1, wherein said M' is Li.
Claim 7
Dependent Claim
280 words
A phosphor which emits light by the excitation of X-rays, having a composition represented by the formula: Ln.sub.1-x-(2/3)y-(1/3)z M".sub.y M'.sub.z DO.sub.4 :xR.sup.3+ where: M" is at least one element selected from the group consisting of Ca, Sr and Cd, M' is at least one alkali metal selected from the group consisting of Li, Na and K, Ln is at least one rare earth element selected from the group consisting of Y, La and Lu, D is Ta, or Ta and Nb, R is at least one activator metal selected from the group consisting of Tm, Ce, Pr, Sm, Eu, Tb, Dy and Yb, y is a value in the range of 1×10 -5 to 1, z is a value in the range of 1×10 -4 to 0.1, and x is a value in the range of 0 to 0.05, said phosphor being obtained by admixing an oxide of Ln in an amount corresponding to 1-x-(2/3)y-(1/3)z parts by mol of Ln, an oxide of D in an amount corresponding to one part by mol of D, an oxide of R in an amount corresponding to x parts by mol of R, a chloride of M' in an amount sufficient to provide z parts by mol of M', and a carbonate of M" in an amount corresponding by y parts by mol of M", the amount of chloride of M' being larger than z parts by mole of M' in said phosphor and firing the admixture at a temperature and for a time sufficient to provide said phosphor having said composition and wherein said phosphor exhibits a smaller afterglow and a greater brightness intensity than the same phosphor absent M" and M'.
Claim 8
Dependent Claim
280 words
A phosphor which emits light by the excitation of X-rays, having a composition represented by the formula: Ln.sub.1-x-(2/3)y-(1/3)z M".sub.y M'.sub.z DO.sub.4 :xR.sup.3+ where: M" is at least one element selected from the group consisting of Ca, Sr and Cd, M' is at least one alkali metal selected from the group consisting of Li, Na and K, Ln is at least one rare earth element selected from the group consisting of Y, La and Lu, D is Ta, or Ta and Nb, R is at least one activator metal selected from the group consisting of Tm, Ce, Pr, Sm, Eu, Tb, Dy and Yb, y is a value in the range of 1×10 -5 to 1, z is a value in the range of 1×10 -4 to 0.1, and x is a value in the range of 0 to 0.05, said phosphor being obtained by admixing an oxide of Ln in an amount corresponding to 1-x-(2/3)y-(1/3)z parts by mol of Ln, an oxide of D in an amount corresponding to one part by mol of D, an oxide of R in an amount corresponding to x parts by mol of R, a chloride of M' in an amount sufficient to provide z parts by mol of M', and a carbonate of M" in an amount corresponding by y parts by mol of M", the amount of chloride of M' being larger than z parts by mole of M' in said phosphor and firing the admixture at a temperature and for a time sufficient to provide said phosphor having said composition and wherein said phosphor exhibits a smaller afterglow and a greater brightness intensity than the same phosphor absent M" and M'.
Claim 9
Dependent Claim
11 words
The phosphor as claimed in claim 6 wherein R is Tm.
Claim 10
Dependent Claim
25 words
An X-ray phosphor as claimed in claim 6 wherein M" is Ca, and y is a value in the range 1×10 -5 ≦y≦3×10 -1 .
Claim 11
Dependent Claim
25 words
An X-ray phosphor as claimed in claim 6 wherein M" is Sr and y is a value in the range 1×10 -5 ≦y≦6×10 -1 .
Claim 12
Dependent Claim
11 words
The phosphor according to claim 6, wherein said Ln is Y.
Claim 13
Dependent Claim
11 words
The phosphor according to claim 6, wherein said M' is Li.
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| 3.5 Years (Year 4) | 1995-06-09 | 1995-12-09 | 1996-06-09 | $2000.00 | Window Closed / Lapsed |
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