Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Patent
1997-12-29
1998-12-01
Hjerpe, Richard A.
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
345 87, 349 61, G09G 336
Patent
active
058445404
ABSTRACT:
A liquid crystal display with a back-light control function is provided with a PWM dimmer driving circuit section for applying a PWM dimming to a fluorescent tube provided on the back surface of a liquid crystal panel by controlling an inverter section. The PWM dimming frequency by the PWM dimmer driving circuit section is set such that m flashes occur (m is an integer of not less than n, and is not a multiple of n) in n screen display periods of the liquid crystal panel (n is an integer of not less than 2), for example, 5 frequency occurs in 2 display periods. Based on a display panel vertical synchronizing signal corresponding to the vertical driving frequency of the liquid crystal panel, the PWM dimmer driving circuit section controls the inverter section while synchronizing a lighting timing of the fluorescent tube with a driving timing of the liquid crystal panel. As a result, an occurrence of flicker and flutter can be prevented effectively. Moreover, a sound noise generated in the inverter section can be reduced. Furthermore, variations in dimming can be reduced.
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Hjerpe Richard A.
Lang Kent C.
Sharp Kabushiki Kaisha
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