Patent ID: 7679592
Filing Date: 2010-03-16
Classification: G09G,H04N

Abstract:
1. A liquid crystal display device to be operated by remote control using a remote controller, comprising: a liquid crystal display unit with a liquid crystal panel being driven by an AC voltage and having a display electrode, to which a voltage based on a video signal is applied, and also having a counter-electrode to which a counter-electrode voltage is applied; a remote control receiver for receiving a flicker adjustment control signal from the remote controller; a microcomputer for outputting a flicker voltage control signal based on the flicker adjustment control signal received by the remote controller; a counter-electrode voltage control unit for generating a flicker adjustment voltage whose value varies according to the flicker voltage control signal from the microcomputer, and for outputting a DC counter-electrode voltage based on the flicker adjustment voltage to the liquid crystal display unit; and a DC-AC converter for converting the DC counter-electrode voltage, output from the counter-electrode voltage control unit, to an AC counter-electrode voltage, which is then applied to the counter-electrode of the liquid crystal display unit; wherein the counter-electrode voltage control unit comprises a voltage amplifier for amplifying the flicker adjustment voltage which, after amplified by the voltage amplifier, is output as the DC counter-electrode voltage to the liquid crystal display unit, wherein the liquid crystal display device further comprises: a first A/D converter for converting the DC counter-electrode voltage output from the voltage amplifier to a digital DC counter-electrode voltage, and outputs the digital DC counter-electrode voltage to the microcomputer; and a second A/D converter for converting an AC counter-electrode voltage output from the liquid crystal display unit to a digital AC counter-electrode voltage, and outputs the digital AC counter-electrode voltage to the microcomputer; wherein the microcomputer compares the digital DC counter-electrode voltage with an average value of the digital AC counter-electrode voltage, and wherein when difference between the digital DC counter-electrode voltage and the average value of the digital AC counter-electrode voltage is equal to or lower than a predetermined threshold value, the microcomputer displays a predetermined color in a color bar display area on the liquid crystal display unit.