Patent US5103133A successfully refreshed from Google Patents.
US5103133A
Expired / Lapsed
US
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Fluorescent lamp having low cathode fall voltage
Assignee: Toshiba Lighting and Technology Corp
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Filing: 1991-02-26
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Granted: 1992-04-07
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Expires: 2011-02-26
Abstract
Abstract A fluorescent lamp of a hot cathode type which is operated with a lamp current of 50 mA or less comprises an outer tube as an envelop, a gas filled in the envelop and a pair of electrodes disposed at both ends of the outer tube in an opposing fashion, at least one of the electrodes being operated in a hot cathode mode. With the fluorescent lamp of the type described, a following relationship is established, p.d≧13, where d represents an inner diameter (cm) of the envelop and p represents an inner pressure (Torr) of the gas filled in the envelop. When the relationship V k ≦15, where V k represents a cathode fall voltage, is further satisfied, the life time of the fluorescent lamp can be elongated.
Inventors
- 👤 Katsuhide Misono
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:49
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/70; H01J61/72; H01J61/02; H01J61/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
129 words
A fluorescent lamp of a hot cathode type which is operated with a lamp current of 50 mA or less, comprising: an outer tube forming an envelop having an inner diameter of d cm; a gas provided in said outer tube for sustaining an electric discharge therein, said gas having a pressure of p Torr; and a pair of electrodes disposed at both ends of said outer tube in an opposing fashion, at least one of said pair of electrodes being operated in a hot cathode mode in which an associated cathode fall voltage has a value of V K ; wherein the following relationships are established between said inner diameter d cm, said pressure p Torr and said cathode fall voltage V K : p.d≧13 and V.sub.K <15.
Claim 2
Dependent Claim
129 words
A fluorescent lamp of a hot cathode type which is operated with a lamp current of 50 mA or less, comprising: an outer tube forming an envelop having an inner diameter of d cm; a gas provided in said outer tube for sustaining an electric discharge therein, said gas having a pressure of p Torr; and a pair of electrodes disposed at both ends of said outer tube in an opposing fashion, at least one of said pair of electrodes being operated in a hot cathode mode in which an associated cathode fall voltage has a value of V K ; wherein the following relationships are established between said inner diameter d cm, said pressure p Torr and said cathode fall voltage V K : p.d≧13 and V.sub.K <15.
Claim 3
Dependent Claim
64 words
A fluorescent lamp according to claim 1, wherein a coil across said at least one pair of electrodes operating in the hot cathode mode is formed of a fine wire having a weight to length ratio of 2 MG (mg/200 mm) or more, where MG is a weight in terms of mg relative to a length of a fine tungsten wire of 200 mm.
Claim 4
Dependent Claim
19 words
A fluorescent lamp according to claim 1, wherein said gas is a rare gas essentially consisting of Argon gas.
Claim 5
Dependent Claim
189 words
A fluorescent lamp of a hot cathode type which is operated with a lamp current of 50 Ma or less comprising: an outer tube forming an envelope having an inner diameter of d cm; a gas provided in said outer tube for sustaining an electric discharge therein, said gas having a pressure of p Torr; a pair of electrodes disposed at both ends of said outer tube in an opposing fashion, at least one of said pair of electrodes being operated in a hot cathode mode in which an associated cathode fall voltage has a value of V K ; wherein the following relationships are established between said inner diameter d cm, said pressure P Torr and said cathode fall voltage V K : p.d≧13 and V.sub.K <15; and a coil across said at least one of said pair of electrodes operating in the hot cathode mode, said coil being formed of a fine wire having a weight to length ratio of 2 MG (mg/200 mm) or more, where MG is a weight in terms of mg relative to a length of a fine tungsten wire of 200 mm.
Claim 6
Dependent Claim
189 words
A fluorescent lamp of a hot cathode type which is operated with a lamp current of 50 Ma or less comprising: an outer tube forming an envelope having an inner diameter of d cm; a gas provided in said outer tube for sustaining an electric discharge therein, said gas having a pressure of p Torr; a pair of electrodes disposed at both ends of said outer tube in an opposing fashion, at least one of said pair of electrodes being operated in a hot cathode mode in which an associated cathode fall voltage has a value of V K ; wherein the following relationships are established between said inner diameter d cm, said pressure P Torr and said cathode fall voltage V K : p.d≧13 and V.sub.K <15; and a coil across said at least one of said pair of electrodes operating in the hot cathode mode, said coil being formed of a fine wire having a weight to length ratio of 2 MG (mg/200 mm) or more, where MG is a weight in terms of mg relative to a length of a fine tungsten wire of 200 mm.
References Cited (Backward Citations)
JPS601744A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-04-07 | 1995-10-07 | 1996-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-07 | 1999-10-07 | 2000-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-07 | 2003-10-07 | 2004-04-07 | $7700.00 | Window Closed / Lapsed |