US4287230A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing a scintillator screen
Assignee: Thales SA
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Filing: 1979-09-17
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Granted: 1981-09-01
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Expires: 1999-09-17
Abstract
Abstract In an X-ray image intensifier consisting of a scintillator screen associated with a photocathode, an electron-optical system and an output screen on which a strong visible image appears, resolution is improved by providing the scintillator screen, formed by a layer of cesium iodide doped with sodium deposited onto the substrate, a structure of needles approximately micrometers in diameter which are kept in the form of separate needles during the subsequent heat treatment by virtue of the presence of silicon oxide in the cesium iodide lattice.
Inventors
- 👤 Jean-Pierre Galves
- 👤 Jean-Marie Gutierrez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:29
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/02; H01J29/10; H01J29/36; H01J29/38; H01J29/385; G; G01; G01T; G01T1/00; G01T1/16; G01T1/20; G01T1/202
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
137 words
A process for the production of a scintillator screen having a substrate and a scintillator layer comprising the steps of keeping the substrate cold, while alternately depositing the vapor condensation cesium iodide doped with sodium and then an oxide and then alternating the deposition of the cesium iodide doped with sodium and the oxide until (a) the desired thickness of the scintillator layer is reached and (b) the deposited layer has a structure of fine needles substantially perpendicular to the substrate and optically independent from one another; and then heat treating the substrate and deposited layer to between 250° to 500° C., said oxide introduced into the crystal lattice of the cesium iodide doped with sodium during the chemical vapor deposition step prevents the needles from coalescing into crystals of larger size during said subsequent heating step.
Claim 2
Dependent Claim
137 words
A process for the production of a scintillator screen having a substrate and a scintillator layer comprising the steps of keeping the substrate cold, while alternately depositing the vapor condensation cesium iodide doped with sodium and then an oxide and then alternating the deposition of the cesium iodide doped with sodium and the oxide until (a) the desired thickness of the scintillator layer is reached and (b) the deposited layer has a structure of fine needles substantially perpendicular to the substrate and optically independent from one another; and then heat treating the substrate and deposited layer to between 250° to 500° C., said oxide introduced into the crystal lattice of the cesium iodide doped with sodium during the chemical vapor deposition step prevents the needles from coalescing into crystals of larger size during said subsequent heating step.
Claim 3
Dependent Claim
20 words
A method as claimed in claim 1, wherein it comprises an additional deposition of cesium iodide after said alternate deposition.
Claim 4
Dependent Claim
17 words
A process according to claim 2 wherein said deposition of cesium iodide forms a substantially homogeneous layer.
Claim 5
Dependent Claim
18 words
A process according to claim 3 wherein said deposited layer has a thickness from 3 to 8 μm.
Claim 6
Dependent Claim
17 words
A process according to claim 1 wherein said needles are approximately 3 to 8 μm in diameter.
Claim 7
Dependent Claim
21 words
A process according to claim 1 or to claim 5 wherein said needles are approximately 100 to 200 μm in length.
Claim 8
Dependent Claim
27 words
A process according to claim 1 wherein the quantity of said oxide deposited with said cesium iodide is less than 1.0% by weight of the cesium iodide.
Claim 9
Dependent Claim
20 words
A process according to claim 1 wherein said oxide is silicon oxide according to the formula SiO x with 1≦×≦2.
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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) | 1984-08-31 | 1985-03-02 | 1985-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-31 | 1989-03-02 | 1989-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-31 | 1993-03-02 | 1993-09-01 | $7700.00 | Window Closed / Lapsed |