Patent US4585972A successfully refreshed from Google Patents.
US4585972A
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Discharge lamp arc tubes
Assignee: Thorn EMI Ltd
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Filing: 1985-01-10
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Granted: 1986-04-29
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Expires: 2005-01-10
Abstract
Abstract An arc discharge lamp is provided using sealing compositions comprising mainly Al 2 O 3 --SiO 2 --MgO. Preferred compositions include between 25 to 28% by weight of MgO and 13 to 21% by weight of Al 2 O 3 since these have lower melting points than others in the group. Additives of B 2 O 3 , nucleating agents and HfO 2 and other rare earth oxides are preferred. The sealing compositions are used to seal end closure members of alumina or CERMET to ceramic arc tubes for use in discharge lamps. The compositions are selected to have linear expansion co-efficients compatible with the materials of the end closures and arc tubes. The methods described give scaling times of between 3 and 4 minutes.
Inventors
- 👤 Peter Hing
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:00
CPC Classifications
C; C04; C04B; C04B37/00; C04B37/02; C04B37/023; C04B37/025; H; H01; H01J; H01J61/00; H01J61/02; H01J61/36; C04B2237/00; C04B2237/02; C04B2237/10; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/343; C04B2237/40; C04B2237/401; C04B2237/50; C04B2237/76; C04B2237/765
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
163 words
An arc tube for a metal halide discharge lamp, said arc tube comprising an envelope of polycrystalline alumina, sapphire or a spinel and one or more cermet end closures hermetically sealed thereto by a sealing composition, said sealing composition consisting of one of: (a) 2.00 to 5.0% by weight of nucleating agent selected from the group consisting of phosphorous pentoxide, titania, zirconia and chromia; (b) 1.96 to 5.0% by weight of boric oxide; and, (c) a member from the group consisting of HfO 2 and the rare earth oxides Y 2 O 3 , Yb 2 O 3 , La 2 O 3 , Dy 2 O 3 and Eu 2 O 3 present in an amount up to 10% by weight; and, the remaining part of said sealing composition consisting of a mixture of silica, alumina and magnesia, there being from 13% to 21% by weight of alumina, and from 25% to 28% by weight of magnesia and the balance being silica.
Claim 2
Dependent Claim
163 words
An arc tube for a metal halide discharge lamp, said arc tube comprising an envelope of polycrystalline alumina, sapphire or a spinel and one or more cermet end closures hermetically sealed thereto by a sealing composition, said sealing composition consisting of one of: (a) 2.00 to 5.0% by weight of nucleating agent selected from the group consisting of phosphorous pentoxide, titania, zirconia and chromia; (b) 1.96 to 5.0% by weight of boric oxide; and, (c) a member from the group consisting of HfO 2 and the rare earth oxides Y 2 O 3 , Yb 2 O 3 , La 2 O 3 , Dy 2 O 3 and Eu 2 O 3 present in an amount up to 10% by weight; and, the remaining part of said sealing composition consisting of a mixture of silica, alumina and magnesia, there being from 13% to 21% by weight of alumina, and from 25% to 28% by weight of magnesia and the balance being silica.
Claim 3
Dependent Claim
31 words
An arc tube for a discharge lamp according to claim 1 wherein said end closure is made from cermet material having a volume fraction of metal ranging from 0.045 to 0.2.
Claim 4
Dependent Claim
23 words
An arc tube for a discharge lamp according to claim 2 wherein the cermet material comprises alumina and tungsten or alumina and molybdenum.
Claim 5
Dependent Claim
17 words
An arc tube for a discharge lamp according to claim 1 wherein the halide comprises sodium bromide.
Claim 6
Dependent Claim
139 words
An arc tube for a metal halide discharge lamp, said arc tube comprising an envelope of polycrystalline alumina, sapphire or a spinel and one or more cermet end closures hermetically sealed thereto by a sealing composition, said sealing composition consisting of a member from the group consisting of HfO 2 and the rare earth oxides Y 2 O 3 , Yb 2 O 3 , La 2 O 3 , Dy 2 O 3 and Eu 2 O 3 in an amount up to 10% by weight to enhance the thermal and mechanical characteristics of the sealing composition and the remaining part of said sealing composition consisting of a mixture of silica, alumina and magnesia, there being from 13% to 21% by weight of alumina, and from 25% to 28% by weight of magnesia and the balance being silica.
Claim 7
Dependent Claim
139 words
An arc tube for a metal halide discharge lamp, said arc tube comprising an envelope of polycrystalline alumina, sapphire or a spinel and one or more cermet end closures hermetically sealed thereto by a sealing composition, said sealing composition consisting of a member from the group consisting of HfO 2 and the rare earth oxides Y 2 O 3 , Yb 2 O 3 , La 2 O 3 , Dy 2 O 3 and Eu 2 O 3 in an amount up to 10% by weight to enhance the thermal and mechanical characteristics of the sealing composition and the remaining part of said sealing composition consisting of a mixture of silica, alumina and magnesia, there being from 13% to 21% by weight of alumina, and from 25% to 28% by weight of magnesia and the balance being silica.
Claim 8
Dependent Claim
101 words
An arc tube for a metal halide discharge lamp, said arc tube comprising an envelope of polycrystalline alumina, sapphire or a spinel and one or more cermet end closures hermetically sealed thereto by a sealing composition, said sealing composition consisting of 2.00 to 5.0% by weight of nucleating agent selected from the group consisting of phosphorous pentoxide, titania, zirconia and chromia and the remaining part of said sealing composition consisting of a mixture of silica, alumina and magnesia, there being from 13% to 21% by weight of alumina, from 25% to 28% by weight of magnesia and the balance being silica.
Claim 9
Dependent Claim
101 words
An arc tube for a metal halide discharge lamp, said arc tube comprising an envelope of polycrystalline alumina, sapphire or a spinel and one or more cermet end closures hermetically sealed thereto by a sealing composition, said sealing composition consisting of 2.00 to 5.0% by weight of nucleating agent selected from the group consisting of phosphorous pentoxide, titania, zirconia and chromia and the remaining part of said sealing composition consisting of a mixture of silica, alumina and magnesia, there being from 13% to 21% by weight of alumina, from 25% to 28% by weight of magnesia and the balance being silica.
Claim 10
Dependent Claim
88 words
An arc tube for a metal halide discharge lamp, said arc tube comprising an envelope of polycrystalline alumina, sapphire or a spinel and one or more cermet end closures hermetically sealed thereto by a sealing composition, said sealing composition consisting of 1.96 to 5.0% weight of boric oxide and the remaining part of said sealing composition consisting of a mixture of silica, alumina and magnesia, there being from 13% to 21% by weight of alumina, from 25% to 28% by weight of magnesia and the balance being silica.
Claim 11
Dependent Claim
88 words
An arc tube for a metal halide discharge lamp, said arc tube comprising an envelope of polycrystalline alumina, sapphire or a spinel and one or more cermet end closures hermetically sealed thereto by a sealing composition, said sealing composition consisting of 1.96 to 5.0% weight of boric oxide and the remaining part of said sealing composition consisting of a mixture of silica, alumina and magnesia, there being from 13% to 21% by weight of alumina, from 25% to 28% by weight of magnesia and the balance being silica.
Claim 12
Dependent Claim
46 words
An arc tube for a discharge lamp according to claim 7 wherein said sealing composition consists of 26.67% by weight of MgO; 19.05% by weight of Al 2 O 3 ; 49.52% by weight of SiO 2 and 4.76% weight of B 2 O 3 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1989-04-28 | 1989-10-28 | 1990-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-28 | 1993-10-28 | 1994-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-28 | 1997-10-28 | 1998-04-29 | $7700.00 | Window Closed / Lapsed |