US4291250A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arc discharge tube end seal
Assignee: Philips North America LLC
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Filing: 1979-05-07
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Granted: 1981-09-22
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Expires: 1999-05-07
Abstract
Abstract An improved arc tube end seal and the method of forming that seal in a high pressure sodium discharge lamp is disclosed. The method includes precoating the refractory metal end cap with a slurry of a mixture of refractory metal powder and powdered metallic silicon and baking the end cap prior to accomplishing the bonding of the end cap to the arc tube with a conventional sealing frit.
Inventors
- 👤 Ranbir S. Bhalla
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:06
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/24; H01J9/26; H01J9/265; H01J9/266; H01J61/00; H01J61/02; H01J61/36
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
102 words
A sealed high pressure sodium discharge lamp arc tube, said arc tube comprising: an elongated alumina arc tube body; a refractory metal end cap associated with each end of said arc tube body; and means sealing said end caps to the ends of said arc tube body, said means sealing said end caps to said ends of said arc tube body including a coating of a refractory metal silicide on the interior surface of said refractory metal end caps and a glassy sealing frit principally comprising alumina and calcia interposed between said refractory metal silicide coating and said alumina arc tube body.
Claim 2
Dependent Claim
102 words
A sealed high pressure sodium discharge lamp arc tube, said arc tube comprising: an elongated alumina arc tube body; a refractory metal end cap associated with each end of said arc tube body; and means sealing said end caps to the ends of said arc tube body, said means sealing said end caps to said ends of said arc tube body including a coating of a refractory metal silicide on the interior surface of said refractory metal end caps and a glassy sealing frit principally comprising alumina and calcia interposed between said refractory metal silicide coating and said alumina arc tube body.
Claim 3
Dependent Claim
30 words
The sealed high pressure sodium discharge lamp arc tube according to claim 1, wherein said alumina arc tube body is polycrystalline alumina and said refractory metal end cap is niobium.
Claim 4
Dependent Claim
53 words
An arc tube for a high pressure sodium discharge lamp comprising: an elongated tubular ceramic arc tube body member; a pair of refractory metal end caps having a refractory metal silicide coating on the interior surface thereof sealed to and closing off the ends of said elongated tubular ceramic arc tube body member.
Claim 5
Dependent Claim
53 words
An arc tube for a high pressure sodium discharge lamp comprising: an elongated tubular ceramic arc tube body member; a pair of refractory metal end caps having a refractory metal silicide coating on the interior surface thereof sealed to and closing off the ends of said elongated tubular ceramic arc tube body member.
Claim 6
Dependent Claim
15 words
The arc tube according to claim 3 wherein said refractory metal end caps are niobium.
Claim 7
Dependent Claim
163 words
A sealed high pressure sodium discharge lamp arc tube, said arc tube comprising: an elongated monolithic alumina arc tube body having circular apertures in the ends thereof of a diameter substantially less than the diameter of the arc tube body; a refractory metal end cap having a refractory metal tubulation extending through the center thereof associated with each end of said arc tube body, with said tubulation extending through said small diameter aperture; and means sealing said end caps and tubulation to the ends of said arc tube body, said means sealing said end caps and tubulation to said ends of said arc tube body including a coating of a refractory metal silicide on the interior surface of said refractory metal end caps and the surface of said tubulation extending through said small diameter aperture in said arc tube body and a glassy sealing frit principally comprising alumina and calcia interposed between said refractory metal silicide coating and said alumina arc tube body.
Claim 8
Dependent Claim
163 words
A sealed high pressure sodium discharge lamp arc tube, said arc tube comprising: an elongated monolithic alumina arc tube body having circular apertures in the ends thereof of a diameter substantially less than the diameter of the arc tube body; a refractory metal end cap having a refractory metal tubulation extending through the center thereof associated with each end of said arc tube body, with said tubulation extending through said small diameter aperture; and means sealing said end caps and tubulation to the ends of said arc tube body, said means sealing said end caps and tubulation to said ends of said arc tube body including a coating of a refractory metal silicide on the interior surface of said refractory metal end caps and the surface of said tubulation extending through said small diameter aperture in said arc tube body and a glassy sealing frit principally comprising alumina and calcia interposed between said refractory metal silicide coating and said alumina arc tube body.
Claim 9
Dependent Claim
33 words
The sealed high pressure sodium discharge lamp arc tube body according to claim 5 wherein said alumina arc tube body is polycrystalline alumina and said refractory metal end caps and tubulations are niobium.
Claim 10
Dependent Claim
36 words
The sealed high pressure sodium discharge lamp arc tube according to claims 1, 3 or 5 wherein said refractory metal silicide is niobium silicide with the ratio of niobium to silicon being about 3 to 7.
References Cited (Backward Citations)
US3281309A
Cited
US3469729A
Cited
US3448319A
Cited
US3598435A
Cited
US3588577A
Cited
US3974410A
Cited
US4103200A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-21 | 1985-03-23 | 1985-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-21 | 1989-03-23 | 1989-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-21 | 1993-03-23 | 1993-09-22 | $7700.00 | Window Closed / Lapsed |