Title:
COLD-CATHODE TUBE LIGHTING DEVICE
Document Type and Number:
WIPO Patent Application WO/2005/109967
Kind Code:
A1
Abstract:
A cold-cathode tube lighting device which uniformly lights up a plurality of cold-cathode tubes with a common power supply to uniformly keep their luminances with high accuracy in the length directions of respective cold-cathode tubes. A first block (1) converts a dc voltage (Vi) into a pair of ac voltages (VA, VB). The low leakage impedance of step-up transformers (5A, 5B) allows the first block (1) to function as a pair of low-impedance power supplies. Second blocks (2) have cold-cathode tubes (20) that are connected one to one. A ballast inductor (LB), when resonated with a matching capacitor (CM), stabilizes a tube current when a cold-cathode tube (20) is lighted. For each cold-cathode tube (20), a synthetic impedance of a matching capacitor (CM) and a surrounding floating capacitance matches the impedance of the ballast inductor (LB). Since a delay circuit (7) allows the phases of two pulse waves (P1, P2) to deviate from each other, the phase difference between ac voltages (VA, VB) is deviated from 180°.
Inventors:
KOMATSU AKEYUKI
MIYAKE EIJI
KAWATAKA KENJI
MIYAKE EIJI
KAWATAKA KENJI
Application Number:
PCT/JP2005/007652
Publication Date:
November 17, 2005
Filing Date:
April 21, 2005
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD (JP)
KOMATSU AKEYUKI
MIYAKE EIJI
KAWATAKA KENJI
KOMATSU AKEYUKI
MIYAKE EIJI
KAWATAKA KENJI
International Classes:
H05B41/24; H01F27/32; H02M7/48; H05B41/282; H01F38/10; (IPC1-7): H05B41/24; H01F38/10; G02F1/3357
Domestic Patent References:
| WO2003056885A1 | 2003-07-10 | |||
| WO2002078403A1 | 2002-10-03 |
Foreign References:
| JPH0619299U | 1994-03-11 | |||
| JPH0590897U | 1993-12-10 | |||
| JP2002353044A | 2002-12-06 | |||
| JP2004119206A | 2004-04-15 | |||
| JPH06301034A | 1994-10-28 | |||
| JPH08288086A | 1996-11-01 | |||
| JPH08273862A | 1996-10-18 | |||
| JP2004241136A | 2004-08-26 | |||
| JP2005063941A | 2005-03-10 |
Attorney, Agent or Firm:
Higashima, Takaharu (IMP Building 3-7, Shiromi 1-chome, Chuo-k, Osaka-shi Osaka, JP)
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