US3898720A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of providing a fluorescent lamp stem with an integral mercury-vapor pressure regulating means
Assignee: Philips North America LLC
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Filing: 1974-05-28
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Granted: 1975-08-12
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Expires: 1994-05-28
Abstract
Abstract The mercury-vapor pressure within a fluorescent lamp is controlled by a metal (indium or an alloy of indium and tin, for example) that wets glass, combines with the mercury within the lamp to form an amalgam and is divided into segments which are fused directly to one or both of the glass stems at spaced locations. The amalgamative-metal segments are of such shape and mass that they inherently remain in place on the stem when they are heat-softened and pressed onto the glass surface. Segments of larger size and mass are retained in place by an overlying porous layer of inert material that adheres to the glass. The amalgamative metal can also be combined with a fusible binder to form a composite which is divided into small pellets that are pressed onto the glass stem and held in place by the adhesive action of the binder when the latter is fused during the bulblehring operation required to fabricate the lamp.
Inventors
- 👤 Chalmers Morehead
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:38
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/70; H01J61/72; H01J9/00; H01J9/02; H01J9/18
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
157 words
In the manufacture of a glass stem assembly for a lowpressure electric discharge lamp of a type that is dosed with a controlled amount of mercury after the stem assembly is sealed to the lamp envelope, the method of providing said stem assembly with integral means for controlling the mercury-vapor pressure within the finished lamp, said method comprising the steps of: forming a compact body of a metal that has a melting point below the softening point of the glass stem assembly and combines with mercury to form an amalgam, heating the glass stem assembly to a temperature above the melting point of the amalgamative-metal, placing the body of amalgamative-metal in contact with the surface of the heated stem assembly until the metal body is fused to the stem assembly, and then maintaining the metal body and stem assembly in such position until they cool and the metal body rigidifies and is secured to the stem assembly.
Claim 2
Dependent Claim
157 words
In the manufacture of a glass stem assembly for a lowpressure electric discharge lamp of a type that is dosed with a controlled amount of mercury after the stem assembly is sealed to the lamp envelope, the method of providing said stem assembly with integral means for controlling the mercury-vapor pressure within the finished lamp, said method comprising the steps of: forming a compact body of a metal that has a melting point below the softening point of the glass stem assembly and combines with mercury to form an amalgam, heating the glass stem assembly to a temperature above the melting point of the amalgamative-metal, placing the body of amalgamative-metal in contact with the surface of the heated stem assembly until the metal body is fused to the stem assembly, and then maintaining the metal body and stem assembly in such position until they cool and the metal body rigidifies and is secured to the stem assembly.
Claim 3
Dependent Claim
42 words
The method of claim 1 wherein said stem assembly has a tubular portion that merges with a flared portion, and said body of amalgamative metal is fused and secured to the tubular portion of the stem assembly adjacent the flared portion thereof.
Claim 4
Dependent Claim
55 words
The method of claim 1 wherein; the stem assembly includes an electrode that is fastened to lead wires anchored in the tubular portion of said stem assembly, and a plurality of amalgamative metal compacts are fused and secured to the surface of the stem assembly in circumferentially-spaced position thereon a predetermined distance from said electrode.
Claim 5
Dependent Claim
99 words
The method of claim 1 wherein; said fused body of amalgamative-metal is of such mass and configuration that it exhibits a tendency to separate from said stem assembly due to its own weight, and a layer of material that is inert with respect to the glass stem assembly, and the dosed mercury and the other discharge-sustaining components of the finished lamp, is deposited over said fused metal body and bonded to the surrounding part of the stem assembly to retain the metal body in place on said stem assembly, said layer of inert material being porous to mercury vapor.
Claim 6
Dependent Claim
25 words
The method of claim 4 wherein said porous layer of inert material consists essentially of finely-divided titanium dioxide, finely-divided zirconium dioxide, or a mixture thereof.
Claim 7
Dependent Claim
35 words
The method of claim 1 wherein; a recess is formed in the surface of said glass assembly, and said compact body of amalgamative-metal is pressed into the recess which thus serves as a retaining-pocket therefor.
Claim 8
Dependent Claim
63 words
The method of claim 6 wherein the exposed surface of said amalgamative-metal body is coated with a layer of material that (a) is inert with respect to the glass stem assembly, and the dosed mercury and the other discharge-sustaining components of the finished lamp, (b) is porous to mercury vapor, and (c) overlies and adheres to the surrounding portion of the glass stem.
Claim 9
Independent Claim
103 words
The method of attaching a body of amalgamative-metal to the surface of a glass stem adapted for use in a low-pressure electric discharge lamp, which method comprises; admixing the amalgamative-metal with amounts of a fusible binder and a non-fusible material sufficient to form a fused porous matrix when heated to a predetermined temperature, shaping the resulting mixture into a pellet-like body and temporarily attaching the latter to the surface of the stem by pressing it thereagainSt, and then heating the stem and pellet-like body to said predetermined temperature to form said fused porous matrix and thereby permanently attach the pellet to the stem.
Claim 10
Independent Claim
103 words
The method of attaching a body of amalgamative-metal to the surface of a glass stem adapted for use in a low-pressure electric discharge lamp, which method comprises; admixing the amalgamative-metal with amounts of a fusible binder and a non-fusible material sufficient to form a fused porous matrix when heated to a predetermined temperature, shaping the resulting mixture into a pellet-like body and temporarily attaching the latter to the surface of the stem by pressing it thereagainSt, and then heating the stem and pellet-like body to said predetermined temperature to form said fused porous matrix and thereby permanently attach the pellet to the stem.
Claim 11
Dependent Claim
20 words
The method of claim 8 wherein said fusible binder comprises boric acid and said non-fusible material comprises titania or zirconia.
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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) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |