DocumentCode :
1149646
Title :
Analytic solution to remove flickers on a liquid crystal display television
Author :
Nam, Hyoungsik ; Oh, Kwan-Young ; Lee, Seung-Woo
Author_Institution :
Samsung Electron. Co., Asan, South Korea
Volume :
55
Issue :
2
fYear :
2009
fDate :
5/1/2009 12:00:00 AM
Firstpage :
818
Lastpage :
823
Abstract :
Flickers have been critical issues on liquid crystal displays (LCDs) which use a backlight unit (BLU) under a panel. The luminance modulation of the backlight and the transmittance of the panel are independently investigated in frequency domain to look for an analytic solution to remove flickers on the LCD panel. The transmittance of the panel depends on how to drive the LC molecules and how the LC molecules respond. We shows there are three frequency components caused by only the panel driving. It is shown that the flicker can be generated by the inter-modulation effect between two different frequency groups from the BLU and the panel. To remove flickers on LCD TV panels, the frequency of the PWM backlight signal should be carefully chosen so that the inter-modulation frequencies may be higher than 60 Hz. It is shown that it is impossible to perceive flickers on an LCDTV operating at 120 Hz refresh rate if the frequency of the PWM signal is 120 Hz or 180 Hz.
Keywords :
intermodulation; liquid crystal displays; television displays; LC molecules; LCD panel; PWM backlight signal; backlight unit; flicker removal; frequency 120 Hz; frequency 180 Hz; inter-modulation frequencies; intermodulation effect; liquid crystal display television; luminance modulation; panel transmittance; Cathode ray tubes; Filtering; Frequency domain analysis; Frequency estimation; Humans; Image quality; Liquid crystal displays; Plasma displays; Pulse width modulation; TV; flicker, PWM, LCD TV, inter-modulation;
fLanguage :
English
Journal_Title :
Consumer Electronics, IEEE Transactions on
Publisher :
ieee
ISSN :
0098-3063
Type :
jour
DOI :
10.1109/TCE.2009.5174460
Filename :
5174460
Link To Document :
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