EP 0406116 B1 19940126 - Process and device for dimming a fluorescent lamp of an LCD backlight.
Title (en)
Process and device for dimming a fluorescent lamp of an LCD backlight.
Title (de)
Verfahren und Vorrichtung zum Dimmen einer Leuchtstofflampe in einer LCD-Anzeigen-Rückbeleuchtung.
Title (fr)
Procédé et dispositif de gradation de lumière pour lampe fluorescente d'éclairage arrière d'écran à cristaux liquides.
Publication
Application
Priority
FR 8908807 A 19890630
Abstract (en)
[origin: EP0406116A1] Device for dimming light, in a ratio which can vary from 1 to 1000, for a fluorescent lamp (34) used in a liquid-crystal display backlighting facility. The device comprises a generator (1-13, 15-20) of square-wave signals formed of periodic pulses of adjustable width (potentiometer 1); these square waves are synchronised by the image synchronising signal (14) for the liquid crystal display. An a.c. voltage generator powers the lamp only during the pulses of the square-wave signals. The drop in output from the lamp (34) for square waves of very short duration enables the desired dimming ratio to be achieved without any image flicker effect. <IMAGE>
IPC 1-7
IPC 8 full level
G02F 1/133 (2006.01); G09G 3/18 (2006.01); G09G 3/34 (2006.01); H05B 41/392 (2006.01)
CPC (source: EP US)
G09G 3/3406 (2013.01 - EP US); H05B 41/3927 (2013.01 - EP US); G09G 2320/0626 (2013.01 - EP US); G09G 2320/064 (2013.01 - EP US); Y10S 315/04 (2013.01 - EP US)
Designated contracting state (EPC)
DE GB IT NL SE
DOCDB simple family (publication)
EP 0406116 A1 19910102; EP 0406116 B1 19940126; CA 2019628 A1 19901231; DE 69006272 D1 19940310; DE 69006272 T2 19940505; FR 2649277 A1 19910104; FR 2649277 B1 19960531; HK 83596 A 19960517; JP H0364895 A 19910320; US 5105127 A 19920414
DOCDB simple family (application)
EP 90401866 A 19900628; CA 2019628 A 19900622; DE 69006272 T 19900628; FR 8908807 A 19890630; HK 83596 A 19960509; JP 17035790 A 19900629; US 54176690 A 19900621