US3897257A
Expired / Lapsed
US
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Light transmitting polycrystalline magnesia member and method of making
Assignee: Philips North America LLC
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Filing: 1973-09-19
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Granted: 1975-07-29
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Expires: 1993-09-19
Abstract
Abstract Light-transmitting polycrystalline member consists essentially of magnesium oxide with from 0.3% to 4% by weight of dysprosium oxide dispersed therein. The density of the member approximates theoretical. To make the member, the desired weight percent of dysprosium oxide powder is dispersed in magnesium oxide powder and the mixture is first isostatically pressed to form a green compact. The compact is then sintered in oxygen at from about 1,800*C to about 2,000*C for at least about 3 hours.
Inventors
- 👤 Tapan K Gupta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:11
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/03; C04B35/04; C04B35/053; C04B35/622; C04B35/64; H; H01; H01J; H01J61/00; H01J61/02; H01J61/30; H01J61/302
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
31 words
A RADIATION-TRANSMITTING POLYCRYSTALLINE MAGNESIA MEMBER HAVING FROM 0.3% TO 4% BY WEIGHT OF DYSPROSIA DISPERSED THEREIN, AND SAID MEMBER HAVING ADENSITY WHICH APPROXIMATES THE THEORETICAL DENSITY OF SAID MAGNESIA PLUS DYSPROSIA.
Claim 2
Dependent Claim
31 words
A RADIATION-TRANSMITTING POLYCRYSTALLINE MAGNESIA MEMBER HAVING FROM 0.3% TO 4% BY WEIGHT OF DYSPROSIA DISPERSED THEREIN, AND SAID MEMBER HAVING ADENSITY WHICH APPROXIMATES THE THEORETICAL DENSITY OF SAID MAGNESIA PLUS DYSPROSIA.
Claim 3
Dependent Claim
21 words
The member as specified in claim 1, wherein up to 50 weight percent of said dysprosia is replaced by calcium oxide.
Claim 4
Dependent Claim
14 words
The member as specified in claim 1, wherein said member has a tubular configuration.
Claim 5
Dependent Claim
15 words
The member as specified in claim 1, wherein said member has a generally planar configuration.
Claim 6
Dependent Claim
24 words
The member as specified in claim 1, wherein said dysprosia is present in amount of from 0.5% to 2% by weight of said magnesia.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-28 | 1979-01-27 | 1979-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-28 | 1983-01-27 | 1983-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-28 | 1987-01-27 | 1987-07-29 | $7700.00 | Window Closed / Lapsed |