US4839243A
Expired / Lapsed
US
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Radiographic intensifying screen
Assignee: Mitsubishi Chemical Corp
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Filing: 1988-07-12
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Granted: 1989-06-13
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Expires: 2008-07-12
Abstract
Abstract A radiographic intensifying screen comprising a support and a fluorescent layer formed thereon, said fluorescent layer consisting essentially of at least one terbium-activated rare earth oxysulfide phosphor of the formula: (Ln.sub.1-x-y, Tb.sub.x, A.sub.y).sub.2 O.sub.2 S (I) wherein Ln is at least one element selected from the group consisting of Y, La, Gd and Lu, A is at least one element selected from the group consisting of Ce, Pr, Nd, Dy, Er and Tm, and x and y are numbers within the ranges of 0.002≦x≦0.20 and 0≦y≦0.01, respectively, and at least one terbium-activated rare earth tantalate complex oxide phosphor of the formula: (Ln'.sub.1-z, Tb.sub.z).sub.2 O.sub.3.mTa.sub.2 O.sub.5.nB.sub.2 O.sub.3 (II) wherein Ln' is at least one element selected from the group consisting of Y, La, Gd and Lu, and z, m and n are numbers within the ranges of 0.0001≦z≦0.1, 0.95≦m≦1.05 and 0≦n≦5.0, respectively.
Inventors
- 👤 Etsuo Shimizu
- 👤 Noboru Kotera
- 👤 Shinichi Onogi
- 👤 Teiichi Hitomi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:25
CPC Classifications
G; G21; G21K; G21K4/00; C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7767; C09K11/7769; C09K11/7771
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
172 words
A radiographic intensifying screen comprising a support and a fluorescent layer formed thereon, said fluorescent layer consisting essentially of at least one terbium-activated rare earth oxysulfide phosphor of the formula: (Ln.sub.1-x-y, Tb.sub.x, A.sub.y).sub.2 O.sub.2 S (I) wherein Ln is at least one element selected from the group consisting of Y, La, Gd and Lu, A is at least one element selected from the group consisting of Ce, Pr, Nd, Dy, Er and Tm, and x and y are numbers within the ranges of 0.002≦x≦0.20 and 0≦y≦0.01 respectively, and at least one terbium-activated rare earth tantalate complex oxide phosphor of the formula: (Ln'.sub.1-z, Tb.sub.z).sub.2 O.sub.3.mTa.sub.2 O.sub.5.nB.sub.2 O.sub.3 (II) wherein Ln' is at least one element selected from the group consisting of Y, La, Gd and Lu, and z, m and n are numbers within the ranges of 0.0005≦z≦0.1, 0.95≦m≦1.05 and 0.01≦n≦5.0, respectively wherein the content of the terbium-activated rare earth tantalate complex oxide phosphor in said fluorescent layer is from 10 to 90% by weight based on the total amount of the phosphors.
Claim 2
Dependent Claim
172 words
A radiographic intensifying screen comprising a support and a fluorescent layer formed thereon, said fluorescent layer consisting essentially of at least one terbium-activated rare earth oxysulfide phosphor of the formula: (Ln.sub.1-x-y, Tb.sub.x, A.sub.y).sub.2 O.sub.2 S (I) wherein Ln is at least one element selected from the group consisting of Y, La, Gd and Lu, A is at least one element selected from the group consisting of Ce, Pr, Nd, Dy, Er and Tm, and x and y are numbers within the ranges of 0.002≦x≦0.20 and 0≦y≦0.01 respectively, and at least one terbium-activated rare earth tantalate complex oxide phosphor of the formula: (Ln'.sub.1-z, Tb.sub.z).sub.2 O.sub.3.mTa.sub.2 O.sub.5.nB.sub.2 O.sub.3 (II) wherein Ln' is at least one element selected from the group consisting of Y, La, Gd and Lu, and z, m and n are numbers within the ranges of 0.0005≦z≦0.1, 0.95≦m≦1.05 and 0.01≦n≦5.0, respectively wherein the content of the terbium-activated rare earth tantalate complex oxide phosphor in said fluorescent layer is from 10 to 90% by weight based on the total amount of the phosphors.
Claim 3
Dependent Claim
39 words
The radiographic intensifying screen according to claim 1, wherein the content of the terbium-activated rare earth tantalate complex oxide phosphor in said fluorescent layer is from 50 to 80% by weight based on the total amount of the phosphors.
Claim 4
Dependent Claim
56 words
The radiographic intensifying screen according to claim 1, wherein the fluorescent layer has a double layer structure comprising a first layer formed on the support and consisting mainly of said terbium-activated rare earth oxysulfide phosphor and a second layer formed on the first layer and consisting mainly of said terbium-activated rare earth tantalate complex oxide phosphor.
Claim 5
Dependent Claim
10 words
The radiographic intensifying screen according to claim 1, wherein 0.98≦m≦1.02.
Claim 6
Dependent Claim
13 words
The radiographic intensifying screen of claim 1, wherein 2×10 -3 ≦z≦5×10 -2 .
Claim 7
Dependent Claim
9 words
The radiographic intensifying screen of claim 1, wherein 0.1≦n≦2.0.
Claim 8
Dependent Claim
50 words
A complex oxide phosphor represented by the formula: (Ln.sub.1-z, Tb.sub.2).sub.2 O.sub.3.mTa.sub.2 O.sub.5.nB.sub.2 O.sub.3 (III) wherein Ln is at least one element selected from the group consisting of Y, La, Gd and Lu, and m, n and z are numbers within the ranges of 0.95≦m≦1.05, 0.01≦n≦5.0 and 5×10 -4 ≦z≦0.1, respectively.
Claim 9
Dependent Claim
50 words
A complex oxide phosphor represented by the formula: (Ln.sub.1-z, Tb.sub.2).sub.2 O.sub.3.mTa.sub.2 O.sub.5.nB.sub.2 O.sub.3 (III) wherein Ln is at least one element selected from the group consisting of Y, La, Gd and Lu, and m, n and z are numbers within the ranges of 0.95≦m≦1.05, 0.01≦n≦5.0 and 5×10 -4 ≦z≦0.1, respectively.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-12 | 1992-12-12 | 1993-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-12 | 1996-12-12 | 1997-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-12 | 2000-12-12 | 2001-06-13 | $7700.00 | Window Closed / Lapsed |