US4374905A
Expired / Lapsed
US
⏱️ 0.0 years remaining
X-Ray intensifying screen
Assignee: General Electric Co
•
Filing: 1978-10-16
•
Granted: 1983-02-22
•
Expires: 1998-10-16
Abstract
Abstract Improved performance of rare earth oxyhalide phosphors in x-ray image intensifying screens may be realized by admixing a small but effective amount of inorganic salts such as MgSO 4 or ZnSO 4 with the phosphor prior to the preparation of the screen. It is believed that H+ and SO 4 =ions are present in a protective surface film surrounding each phosphor particle to help preserve the original emission brightness of the phosphor when exposed to humidity as well as reduce attack by volatile organic components which migrate from an associated photographic film.
Inventors
- 👤 Jacob G. Rabatin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:28
CPC Classifications
G; G21; G21K; G21K4/00; B; B32; B32B; B32B19/00; B32B19/04; C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7728; C09K11/7732; C09K11/7733; G03; G03C; G03C5/00; G03C5/16; G03C5/17; G21K2004/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
119 words
An improved x-ray screen including a backing member coated with a physical admixture of a rare earth oxyhalide phosphor selected from lanthanum oxyhalide and gadolinium oxyhalide activated by T x wherein T x is chosen from Tm and Tb and an inorganic salt selected from MgSO 4 and ZnSO 4 added in sufficient quantity from a small but effective amount up to 4 weight percent based on the phosphor weight to retain original emission brightness for a longer time period than for said phosphor without said inorganic salt, said admixture further being adhesively bonded with a polymer binder to said backing member, and said improved x-ray screen resisting loss in film speed and brightness when associated with photographic film.
Claim 2
Dependent Claim
119 words
An improved x-ray screen including a backing member coated with a physical admixture of a rare earth oxyhalide phosphor selected from lanthanum oxyhalide and gadolinium oxyhalide activated by T x wherein T x is chosen from Tm and Tb and an inorganic salt selected from MgSO 4 and ZnSO 4 added in sufficient quantity from a small but effective amount up to 4 weight percent based on the phosphor weight to retain original emission brightness for a longer time period than for said phosphor without said inorganic salt, said admixture further being adhesively bonded with a polymer binder to said backing member, and said improved x-ray screen resisting loss in film speed and brightness when associated with photographic film.
References Cited (Backward Citations)
US2421208A
Cited
US3070435A
Cited
US3023313A
Cited
GB999780A
Cited
US3617743A
Cited
US3795814A
Cited
US4138361A
Cited
US4020231A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-21 | 1986-08-23 | 1987-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-21 | 1990-08-23 | 1991-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-21 | 1994-08-23 | 1995-02-22 | $7700.00 | Window Closed / Lapsed |