Patent US4928037A successfully refreshed from Google Patents.
US4928037A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protected discharge lamp lighting system
Assignee: Hitachi Ltd
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Filing: 1988-12-20
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Granted: 1990-05-22
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Expires: 2008-12-20
Abstract
Abstract A discharge lamp lighting system including at least one switch device connected between a d.c. power supply and a discharge lamp which is turned on by a high frequency power generated through turning-on and -off of the switching device. In the discharge lighting system, the discharge lamp lighting operation is allowed to start when the d.c. power supply voltage reaches a predetermined voltage value A or over, and the discharge lamp lighting operation is stopped when the d.c. power supply voltage lowers smaller than a predetermined voltage value B, where the values A and B take a relation that B is smaller than A.
Inventors
- 👤 Kenji Kawabata
- 👤 Soichiro Ogawa
- 👤 Ryoichi Masaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:29
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/26; H05B41/28; H05B41/282; H05B41/285; H05B41/2851; H05B41/2853; Y; Y10; Y10S; Y10S315/00; Y10S315/05
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
181 words
A discharge lamp lighting system comprising: a d.c. power supply; a lighting circuit to which an output from said d.c. power supply is supplied and from which a high frequency voltage is generated; a discharge lamp connected at the output side of said lighting circuit; and a lighting control circuit connected between said d.c. power supply and said lighting circuit, said lighting control circuit being constructed such that if a detected output voltage of said d.c. power supply is lower than a voltage value A at which a lamp discharge start voltage can be obtained, the operation of said lighting circuit is not allowed to start operating, when said detected output voltage reaches the voltage value A or over, said lighting circuit is caused to start operating and apply the start voltage to said discharge lamp to turn on said lamp, and after turning-on of said discharge lamp, when the output voltage of said d.c. power supply lowers smaller than a voltage value B at which said discharge lamp can still maintain its normal discharge said lighting circuit operation is stopped.
Claim 2
Dependent Claim
181 words
A discharge lamp lighting system comprising: a d.c. power supply; a lighting circuit to which an output from said d.c. power supply is supplied and from which a high frequency voltage is generated; a discharge lamp connected at the output side of said lighting circuit; and a lighting control circuit connected between said d.c. power supply and said lighting circuit, said lighting control circuit being constructed such that if a detected output voltage of said d.c. power supply is lower than a voltage value A at which a lamp discharge start voltage can be obtained, the operation of said lighting circuit is not allowed to start operating, when said detected output voltage reaches the voltage value A or over, said lighting circuit is caused to start operating and apply the start voltage to said discharge lamp to turn on said lamp, and after turning-on of said discharge lamp, when the output voltage of said d.c. power supply lowers smaller than a voltage value B at which said discharge lamp can still maintain its normal discharge said lighting circuit operation is stopped.
References Cited (Backward Citations)
US4554487A
Cited
JPS6157500A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-21 | 1993-11-20 | 1994-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-21 | 1997-11-20 | 1998-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-21 | 2001-11-20 | 2002-05-22 | $7700.00 | Window Closed / Lapsed |