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US4174973A
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Transparent yttria ceramics containing magnesia or magnesium aluminate
Assignee: Osram Sylvania Inc
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Filing: 1979-01-29
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Granted: 1979-11-20
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Expires: 1999-01-29
Abstract
Abstract An article of manufacture comprising a substantially transparent high density polycrystalline yttria-based body consisting essentially of yttria and from 0.1 to 5 wt. % MgO or from 0.1 to 5 wt. % MgAl 2 O 4 . Transparent yttria-based bodies according to this invention are particularly useful as envelopes for high pressure sodium vapor lamps.
Inventors
- 👤 William H. Rhodes
- 👤 F. Joseph Reid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:08
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/50; C04B35/505
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
35 words
A substantially transparent, high density polycrystalline yttria-based body consisting essentially of yttria and about 0.1% to 5% by weight of a material selected from the group consisting of MgO and MgAl 2 O 4 .
Claim 2
Dependent Claim
35 words
A substantially transparent, high density polycrystalline yttria-based body consisting essentially of yttria and about 0.1% to 5% by weight of a material selected from the group consisting of MgO and MgAl 2 O 4 .
Claim 3
Dependent Claim
12 words
The yttria-based body according to claim 1 wherein said material is MgO.
Claim 4
Dependent Claim
23 words
The yttria-based body according to claim 2 wherein the MgO is present in an amount of between about 0.3% to 1.5% by weight.
Claim 5
Dependent Claim
16 words
The yttria-based body according to claim 1 wherein said material is MgAl 2 O 4 .
Claim 6
Dependent Claim
26 words
The yttria-based body according to claim 4 wherein the MgAl 2 O 4 is present in an amount of between about 0.1% to 1% by weight.
References Cited (Backward Citations)
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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) | 1982-11-19 | 1983-05-21 | 1983-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-19 | 1987-05-21 | 1987-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-19 | 1991-05-21 | 1991-11-20 | $7700.00 | Window Closed / Lapsed |