Patent US4001623A successfully refreshed from Google Patents.
US4001623A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arc tube for high-pressure mercury/metal halide lamp
Assignee: EMI Group Ltd
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Filing: 1975-03-18
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Granted: 1977-01-04
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Expires: 1995-03-18
Abstract
Abstract A high-pressure mercury/metal-halide discharge lamp has the discharge electrodes offset below the central axis of the arc tube to increase the uniformity of the wall temperature and improve the performance of the lamp. The upper part of the arc tube wall is shaped to be nearer the electrodes at the ends and further from them at the center than in a cylindrical tube.
Inventors
- 👤 Donald Arthur Howles
- 👤 Robert Brian Page
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:00
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/82; H01J61/827; H01J61/02; H01J61/30
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
120 words
In a high-pressure mercury/metal halide discharge lamp for operation in a horizontal position, said lamp having an arc tube comprising a bulb closed at each end by a press seal and containing discharge electrodes, the bulb having a wall which is symmetrical about a plane generally parallel to the press seals, the improvement wherein the bulb wall has a part-cylindrical portion having a cylinder axis lying in said plane, said portion being below said cylinder axis when the lamp is in its horizontal operating position, and said discharge electrodes are positioned in alignment with one another in said plane and offset in the same direction below said cylinder axis to lie between the cylinder axis and said part-cylindrical wall portion.
Claim 2
Dependent Claim
120 words
In a high-pressure mercury/metal halide discharge lamp for operation in a horizontal position, said lamp having an arc tube comprising a bulb closed at each end by a press seal and containing discharge electrodes, the bulb having a wall which is symmetrical about a plane generally parallel to the press seals, the improvement wherein the bulb wall has a part-cylindrical portion having a cylinder axis lying in said plane, said portion being below said cylinder axis when the lamp is in its horizontal operating position, and said discharge electrodes are positioned in alignment with one another in said plane and offset in the same direction below said cylinder axis to lie between the cylinder axis and said part-cylindrical wall portion.
Claim 3
Dependent Claim
69 words
In a lamp as claimed in claim 1 the further improvement wherein said bulb wall has at each end a first end portion lying on one side of said cylinder axis and adjacent said part-cylindrical portion and a second end portion lying on the other side of said cylinder axis, said second end portion being closer to the electrode than an imaginary surface symmetrical with said first end portion.
Claim 4
Dependent Claim
34 words
In a lamp as claimed in claim 2 the further improvement wherein said bulb wall has a middle portion disposed opposite and part-cylindrical portion and further from the cylinder axis than said part-cylindrical portion.
Claim 5
Dependent Claim
77 words
In a lamp as claimed in claim 1, the further improvement wherein the said bulb wall has a profile in the said plane which comprises a straight line at the intersection of said part-cylindrical portion with said plane, two arcs of circles having centres above the tips of the discharge electrodes, and a third arc of larger radius joining the first two arcs, the centre of the third arc lying on a line midway between the electrodes.
Claim 6
Dependent Claim
34 words
In a lamp as claimed in claim 1, the further improvement wherein the offset of said discharge electrodes from the cylinder axis is between one-fifth and four-fifths of the radius of said part-cylindrical portion.
References Cited (Backward Citations)
US2830210A
Cited
US2845557A
Cited
US2888585A
Cited
US3093769A
Cited
US3614508A
Cited
US3798487A
Cited
US3858078A
Cited
US3896326A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-04 | 1980-07-05 | 1981-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-04 | 1984-07-05 | 1985-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-04 | 1988-07-05 | 1989-01-04 | $7700.00 | Window Closed / Lapsed |