EP0272930A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Ceramic envelope device for high-pressure discharge lamp
Assignee: NGK Insulators Ltd
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Filing: 1987-12-23
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Granted: —
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Expires: 2007-12-23
Abstract
Abstract A ceramic envelope device (6) for use in a HID (high intensity discharge) lamp, which includes: (a) a translucent ceramic tube (12); (b) a pair of electrically conductive end caps (14, 14) which close longitudinally opposite ends of the ceramic tube; (c) a pair of oppositely located discharge electrodes (16, 16) each of which is supported at a first end thereof by a corresponding one of the end caps such that a second end of each electrode protrudes from an inner surface (18) of the corresponding end cap in a longitudinally inward direction in the ceramic tube; (d) an electrical insulator (20) provided for one or both of the pair of end caps; and (e) a sealing member (30) disposed to maintain fluid-tightness between an engaging portion (14a) of the end cap for which the electrical insulator is provided, and the corresponding end of the ceramic tube. The electrical insulator includes a peripheral portion (46) which covers a peripheral portion of the inner surface of the corresponding end cap, and the end of the ceramic tube sealed by the sealing member includes a contact portion (44) which contacts the peripheral portion of the electrical insulator, to thereby isolate the sealing member from an inner space (50) in which the second end of each discharge electrode extends.
Inventors
- 👤 Mikio Lunetsurumai 402 Kariya
- 👤 Hirotsugu Esupoahorita 802 Izumiya
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 08:47
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/36; H01J61/366
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
258 words
A ceramic envelope device for a high-pressure metal-vapor discharge lamp, comprising: a translucent ceramic tube (12) having longitudinally opposite ends; a pair of electrically conductive end caps (14, 14) which close said opposite ends of said translucent ceramic tube, respectively, each of said end caps having an engaging portion (14a) which engages the corresponding one of said opposite ends of the translucent ceramic tube; a pair of oppositely located discharge electrodes (16, 16) each of which is supported at a first end thereof by a corresponding one of said end caps such that a second end of said each discharge electrode opposite to said first end thereof protrudes from an inner surface (18) of said corresponding end cap in a longitudinally inward direction in said ceramic tube; an electrical insulator (20) provided for at least one of said pair of end caps, said electrical insulator covering at least the inner surface of the end cap; and a sealing member (30) disposed to maintain fluid-tightness between said engaging portion of the or each end cap for which a said electrical insulator is provided, and the corresponding end of said ceramic tube, said electrical insulator including a peripheral portion (46) which covers a peripheral portion of said inner surface of the end cap, the end of said translucent ceramic tube sealed by said sealing member including a contact portion (44) which contacts said peripheral portion of said electrical insulator, to thereby isolate said sealing member from an inner space (50) in which said second end of said discharge electrodes protrudes.
Claim 2
Dependent Claim
258 words
A ceramic envelope device for a high-pressure metal-vapor discharge lamp, comprising: a translucent ceramic tube (12) having longitudinally opposite ends; a pair of electrically conductive end caps (14, 14) which close said opposite ends of said translucent ceramic tube, respectively, each of said end caps having an engaging portion (14a) which engages the corresponding one of said opposite ends of the translucent ceramic tube; a pair of oppositely located discharge electrodes (16, 16) each of which is supported at a first end thereof by a corresponding one of said end caps such that a second end of said each discharge electrode opposite to said first end thereof protrudes from an inner surface (18) of said corresponding end cap in a longitudinally inward direction in said ceramic tube; an electrical insulator (20) provided for at least one of said pair of end caps, said electrical insulator covering at least the inner surface of the end cap; and a sealing member (30) disposed to maintain fluid-tightness between said engaging portion of the or each end cap for which a said electrical insulator is provided, and the corresponding end of said ceramic tube, said electrical insulator including a peripheral portion (46) which covers a peripheral portion of said inner surface of the end cap, the end of said translucent ceramic tube sealed by said sealing member including a contact portion (44) which contacts said peripheral portion of said electrical insulator, to thereby isolate said sealing member from an inner space (50) in which said second end of said discharge electrodes protrudes.
Claim 3
Dependent Claim
59 words
A ceramic envelope device as claimed in claim 1, further comprising a pair of electrical lead members (8, 8) through which electric power is supplied to said pair of discharge electrodes (16, 16) via said pair of end caps (14, 14), respectively, each of said electrical lead members being supported on an outer surface of the corresponding end cap.
Claim 4
Dependent Claim
24 words
A ceramic envelope device as claimed in claim 1 or claim 2, wherein said end caps (1,414) are made of an electrically conductive cermet.
Claim 5
Dependent Claim
120 words
A ceramic envelope device as claimed in any one of claims 1 to 3, wherein the end of said ceramic tube (12) sealed by said sealing member (30) includes a first inner cylindrical surface (41) having a first inside diameter, and a second inner cylindrical surface (42) which is located axially inwardly of said first inner cylindrical surface, said second inner cylindrical surface having a second inside diameter smaller than said first inside diameter, said engaging portion (14a) of said each of said at least one end cap (14) for which said electrical insulator (20) and said sealing member (30) are provided having a diameter which is smaller than said first inside diameter and greater than said second inside diameter.
Claim 6
Dependent Claim
44 words
A ceramic envelope device as claimed in claim 4, wherein said contact portion of the end of the translucent ceramic tube (12) sealed by said sealing member (30) has a shoulder surface (44) disposed between said first and second inner cylindrical surfaces (41, 42).
Claim 7
Dependent Claim
26 words
A ceramic envelope device as claimed in claim 5, wherein said shoulder surface (44) is perpendicular to said first and second inner cylindrical surfaces (41, 42).
Claim 8
Dependent Claim
76 words
A ceramic envelope device as claimed in any one of claims 1 to 3, wherein the end of said translucent ceramic tube (12) sealed by said sealing member (30) has a tapered bore defined by a tapered inner surface, while said engaging portion (14a) of the corresponding end cap (14) has a tapered outer surface whose taper angle is smaller than that of said tapered inner surface, said contact portion consisting of said tapered inner surface.
References Cited (Backward Citations)
No citation records indexed.
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