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US5371377A
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Method of erasing energy stored in a photostimulable phosphor medium
Assignee: Agfa HealthCare NV
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Filing: 1993-08-26
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Granted: 1994-12-06
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Expires: 2013-08-26
Abstract
Abstract A method of erasing energy stored in a photostimulable Eu 2+ doped alkaline earth halide phosphor medium, wherein in said method after imagewise exposure of said medium to penetrating radiation and read out of stored energy by photostimulation with light in the wavelength range of 430 to 550 nm, said phosphor medium is exposed in a single erasure step with light mainly within the 370 to 530 nm range containing two distinct or separate emission bands, one of which is peaking at or near 400 nm and the other at or near 500 nm.
Inventors
- 👤 Luc Struye
- 👤 Paul Leblans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:20
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/20; G01T1/2012; G01T1/2016
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
98 words
A method of erasing energy stored in a medium containing a photostimulable Eu 2+ doped alkaline earth halide phosphor, wherein in said method after imagewise exposure of said phosphor to penetrating radiation and read out of stored energy by photostimulation with light in the wavelength range of 430 to 550 nm, said phosphor for its erasure is exposed in a single erasure step with light mainly within the 370 to 530 nm range containing two distinct or separate emission bands, one of which is peaking at or near 400 nm and the other at or near 500 nm.
Claim 2
Independent Claim
98 words
A method of erasing energy stored in a medium containing a photostimulable Eu 2+ doped alkaline earth halide phosphor, wherein in said method after imagewise exposure of said phosphor to penetrating radiation and read out of stored energy by photostimulation with light in the wavelength range of 430 to 550 nm, said phosphor for its erasure is exposed in a single erasure step with light mainly within the 370 to 530 nm range containing two distinct or separate emission bands, one of which is peaking at or near 400 nm and the other at or near 500 nm.
Claim 3
Dependent Claim
48 words
Method according to claim 1, wherein the erasure proceeds with said light in the 370 to 530 nm range being composed such that the ultraviolet light emitted in the 370-400 nm range is less than 50% of the energy emitted as visible light in the 400-500 nm range.
Claim 4
Dependent Claim
26 words
Method according to claim 1, wherein the erasure proceeds with an erasure source containing an ultraviolet-stimulable fluorescent means in conjunction with an ultraviolet radiation emitting means.
Claim 5
Dependent Claim
27 words
Method according to claim 3, wherein said fluorescent means is a supported phosphor coating containing at least one phosphor emitting fluorescent light when struck with ultraviolet radiation.
Claim 6
Dependent Claim
20 words
Method according to claim 3, wherein said ultraviolet radiation emitting means is one or more high pressure mercury vapor lamps.
Claim 7
Dependent Claim
37 words
Method according to claim 1, wherein the erasure proceeds with fluorescent light emitted by a mixture of two fluorescent lamp phosphors corresponding respectively to the following empirical formulae: Sr.sub.O.8 Mg.sub.1.2 P.sub.2 O.sub.7 :Eu and MgOGa.sub.2 O.sub.3 :Mn.
Claim 8
Dependent Claim
21 words
Method according to claim 1, wherein the erasure proceeds with fluorescent light having an emission spectrum as shown in FIG. 1.
Claim 9
Dependent Claim
37 words
Method according to claim 1, wherein said Eu 2+ doped alkaline earth halide phosphor is an europium(II)-barium fluorohalide phosphor in which barium is partly replaced by strontium and fluorine is present in excess over the other halide(s).
Claim 10
Dependent Claim
177 words
Method according to claim 1, wherein said phosphor corresponds to the following empirical formula: Ba.sub.1-x-y-p-3q-z Sr.sub.x M.sub.y.sup.II M.sub.2p.sup.I M.sub.2q.sup.III F.sub.2-a-b Br.sub.a X.sub.b :zA wherein: X i s at 1 east one halogen selected from the group consisting of C1 and I: M I is at least one alkali metal selected from the group consisting of Li Na, K, Rb and Cs; M II is at least one alkaline earth metal selected from the group consisting of Ca and Mg; M III is at least one metal selected from the group consisting of Al, Ga, In, T1, Sb, Bi, Y or a trivalent lanthanide, e.g. La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; a is a number satisfying the conditions of 0.85≦a≦0.96 when x is 0.17≦x≦0.55 and 0.90≦a≦0.96 when x is 0.12≦x≦0.17; y is in the range 0≦y≦O.10; b is in the range 0≦b≦0.15; p is in the range 0≦p≦0.3; q is in the range 0≦q≦O.1; z is in the range 10 -6 ≦z≦10 -2 , and A is Eu 2+ .
Claim 11
Dependent Claim
18 words
Method according to claim 1, wherein said read out proceeds with argon ion laser light of 488 nm.
Claim 12
Independent Claim
162 words
An apparatus for recording and reproducing a pattern of penetrating radiation, which apparatus comprises: (1) a recording and storage means containing a photostimulable storage phosphor of the Eu 2+ doped alkaline earth metal fluorohalides capable of storing energy when struck by said penetrating radiation, (2) a read out means for generating stimulating rays in the wavelength range of 430 nm to 550 nm to which said photostimulable phosphor after storing therein the energy of said penetrating radiation is exposed, (3) a detection means for detecting fluorescent light emitted from the photostimulable phosphor by irradiation with said stimulating rays, and (4) an erasure means for erasing energy left in said phosphor after said detection, wherein said means is a light source or plurality of light sources capable of emitting light mainly within the 370 to 530 nm range containing two distinct or separate emission bands, one of which is peaking at or near 400 nm and the other at or near 500 nm.
Claim 13
Independent Claim
162 words
An apparatus for recording and reproducing a pattern of penetrating radiation, which apparatus comprises: (1) a recording and storage means containing a photostimulable storage phosphor of the Eu 2+ doped alkaline earth metal fluorohalides capable of storing energy when struck by said penetrating radiation, (2) a read out means for generating stimulating rays in the wavelength range of 430 nm to 550 nm to which said photostimulable phosphor after storing therein the energy of said penetrating radiation is exposed, (3) a detection means for detecting fluorescent light emitted from the photostimulable phosphor by irradiation with said stimulating rays, and (4) an erasure means for erasing energy left in said phosphor after said detection, wherein said means is a light source or plurality of light sources capable of emitting light mainly within the 370 to 530 nm range containing two distinct or separate emission bands, one of which is peaking at or near 400 nm and the other at or near 500 nm.
Claim 14
Dependent Claim
47 words
Apparatus according to claim 11, wherein the erasure means emits light in the 370 to 530 nm range being composed such that the ultraviolet light emitted in the 370-400 nm range is less than 50% of the energy emitted as visible light in the 400-500 nm range.
Claim 15
Dependent Claim
26 words
Apparatus according to claim 12, wherein said erasure means is an erasure source containing an ultraviolet-stimulable fluorescent means in conjunction with an ultraviolet radiation emitting means.
References Cited (Backward Citations)
JPH02272440A
Cited
US5065021A
Cited
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