Patent US4079167A successfully refreshed from Google Patents.
US4079167A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chemically polished polycrystalline alumina material
Assignee: General Electric Co
•
Filing: 1975-06-25
•
Granted: 1978-03-14
•
Expires: 1995-06-25
Abstract
Abstract Increased optical transmission is provided for a body of light transmissive polycrystalline alumina body treated at elevated temperatures with a molten flux composition. A tube of the flux polished material which can be used as the light transmissive envelope for high intensity discharge lamps especially sodium vapor lamps, improves light output from the lamp as the result of increased in-line transmission for the treated envelope member. A method of chemically polishing polycrystalline alumina material in this manner is also disclosed.
Inventors
- 👤 Garland E. Scott, Jr.
- 👤 Michael K. Levenson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:27
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/115; C04B41/53; C04B41/5338; C04B41/5361; C04B41/80; C04B41/91; G; G02; G02B; G02B1/00; G02B1/02; H; H01; H01J; H01J61/00; H01J61/02; H01J61/30; H01J61/302; H01J9/00; H01J9/24; H01J9/245; H01J9/247; Y; Y10; Y10T; Y10T428/00; Y10T428/31; Y10T428/315
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
48 words
As an article of manufacture, a high density, polycrystalline alumina body having flux polished major surfaces so as to reduce the high spots on the individual exterior alumina crystals without materially introducing low spots at the grain boundaries and thereby to obtain increased optical transmission upon flux removal.
Claim 2
Dependent Claim
48 words
As an article of manufacture, a high density, polycrystalline alumina body having flux polished major surfaces so as to reduce the high spots on the individual exterior alumina crystals without materially introducing low spots at the grain boundaries and thereby to obtain increased optical transmission upon flux removal.
Claim 3
Dependent Claim
67 words
An article of manufacture as in claim 1 wherein the polycrystalline alumina comprises high purity alumina having an in-line transmission of not less than 0.5% per millimeter thickness of said alumina body, for radiant energy of all wavelengths in a wavelength range from about 0.3 micron to about 6.6 microns and having an in-line transmission of not less than 10% at some wavelength within said wavelength range.
Claim 4
Dependent Claim
28 words
An article of manufacture as in claim 1 wherein the polycrystalline alumina comprises high purity alumina containing a small but effective amount up to 0.5 weight percent magnesia.
Claim 5
Dependent Claim
19 words
An article of manufacture as in claim 3 wherein the magnesia content is present primarily as an alumina-magnesia spinel.
References Cited (Backward Citations)
US1806589A
Cited
US2510219A
Cited
US3042566A
Cited
US3026210A
Cited
US3026177A
Cited
GB1034122A
Cited
US3311482A
Cited
US3619309A
Cited
US3899560A
Cited
US3808065A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-13 | 1981-09-12 | 1982-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-13 | 1985-09-12 | 1986-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-13 | 1989-09-12 | 1990-03-14 | $7700.00 | Window Closed / Lapsed |