US4961024A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circular fluorescent lamp with oval section of tube
Assignee: Hitachi Ltd
•
Filing: 1988-06-24
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Granted: 1990-10-02
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Expires: 2008-06-24
Abstract
Abstract A circular fluorescent lamp has a fluorescent tube of a generally circular shape having electrodes fixed gastight in both of its ends respectively to enclose inert gas and mercury therein. A cap is mounted to bridge between the tube ends. The fluorescent tube has an oval section taken along a line perpendicular with respect to its axis. The rate of ovalness y/x, representing the ratio between the larger tube diameter y and the smaller tube diameter x of the tube sectional shape, preferably lies within the range of 1.10 to 1.30.
Inventors
- 👤 Churyo Kodama
- 👤 Yasuo Hirasawa
- 👤 Yukio Ohno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:06
CPC Classifications
H; H01; H01J; H01J5/00; H01J5/02; H01J61/00; H01J61/02; H01J61/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
142 words
A circular fluorescent lamp, comprising: a fluorescent tube of a generally circular shape having electrodes fixed in both ends thereof respectively and enclosing inert gas and mercury therein, and a cap mounted to bridge between said tube ends, said fluorescent tube having an oval sectional shape relative to a line perpendicular with respect to the tube axis, wherein the oval sectional shape has a rate of ovalness y/x representing the ratio between a larger tube diameter y and a smaller tube diameter x of the oval sectional shape that lies within the range of 1.10 to 1.30, and wherein said larger tube diameter y is in the range of 30 to 34 mm, said smaller tube diameter x is in the range of 25 to 29 mm, and said fluorescent tube has a thickness in the range of 0.7 to 1.0 mm.
Claim 2
Dependent Claim
142 words
A circular fluorescent lamp, comprising: a fluorescent tube of a generally circular shape having electrodes fixed in both ends thereof respectively and enclosing inert gas and mercury therein, and a cap mounted to bridge between said tube ends, said fluorescent tube having an oval sectional shape relative to a line perpendicular with respect to the tube axis, wherein the oval sectional shape has a rate of ovalness y/x representing the ratio between a larger tube diameter y and a smaller tube diameter x of the oval sectional shape that lies within the range of 1.10 to 1.30, and wherein said larger tube diameter y is in the range of 30 to 34 mm, said smaller tube diameter x is in the range of 25 to 29 mm, and said fluorescent tube has a thickness in the range of 0.7 to 1.0 mm.
Claim 3
Dependent Claim
39 words
A circular fluorescent lamp according to claim 1, wherein said fluorescent tube has said oval sectional shape in a range excluding said tube ends and said cap, and said range has a central angle θ of at least 270°.
Claim 4
Dependent Claim
25 words
A circular fluorescent lamp according to claim 1, wherein said fluorescent tube has a wall forming said larger tube diameter y that is generally flat.
Claim 5
Dependent Claim
24 words
A circular fluorescent lamp according to claim 1, wherein said fluorescent tube has a wall forming said larger tube diameter y that is convex.
References Cited (Backward Citations)
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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) | 1993-10-01 | 1994-04-02 | 1994-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-01 | 1998-04-02 | 1998-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-01 | 2002-04-02 | 2002-10-02 | $7700.00 | Window Closed / Lapsed |