IMPROVING THE LUMINANCE AND LUMINOUS EFFICACY OF MINIATURE FLUORESCENT LAMPS FOR LIQUID-CRYSTAL DISPLAY BACKLIGHTING BY USING A DOUBLE FREQUENCY DRIVE

Citation
T. Shiga et al., IMPROVING THE LUMINANCE AND LUMINOUS EFFICACY OF MINIATURE FLUORESCENT LAMPS FOR LIQUID-CRYSTAL DISPLAY BACKLIGHTING BY USING A DOUBLE FREQUENCY DRIVE, Review of scientific instruments, 69(9), 1998, pp. 3426-3432
Citations number
7
Categorie Soggetti
Physics, Applied","Instument & Instrumentation
ISSN journal
00346748
Volume
69
Issue
9
Year of publication
1998
Pages
3426 - 3432
Database
ISI
SICI code
0034-6748(1998)69:9<3426:ITLALE>2.0.ZU;2-E
Abstract
A new method of driving miniature fluorescent tubes for liquid crystal display backlighting, with diameters as small as 2 mm, has been devis ed with the objective of improving the luminance and luminous efficaci es of such lamps. The driver voltage wave form consists of high freque ncy oscillations at the leading and trailing edges of conventional squ are-wave form voltage pulses of relatively low frequency. The wave for m is produced simply by inserting coils between low frequency square-w ave pulse generators and the lamp electrodes. A lamp driven in this wa y operates in a different discharge mode from the conventional glow di scharge obtained in the absence of the coils. The twofold intensity in crease of visible emission from the positive column region indicates t hat the vacuum ultraviolet emission increases: enhancing the excitatio n of the phosphor in the lamp, There is evidence that the luminous eff icacy is also increased by a factor of 2 as a result of more efficient use of the input energy. The minimum voltage needed to maintain a dis charge is reduced. (C) 1998 American Institute of Physics. [S0034-6748 (98)04409-8]