| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent performance from being deteriorated due to resonance of a light guide plate and to avoid sound quality deterioration sensible in hearing in the case where the volume of output sound is low, in a liquid crystal display device comprising the light guide plate which is cantilever-supported and of which the resonant frequency partially overlaps the frequency band of output sound of a speaker. Ž<P>SOLUTION: A sound processing circuit 23 performs notch filter processing for attenuating a signal component of a specific frequency band in an sound signal input to a speaker 25 but in the case where the volume level of the sound signal is lower than a predetermined threshold level, the sound processing circuit 23 cancels filter processing to the sound signal, wherein the specific frequency band is the band of a resonant frequency of a cantilever-supported light guide plate. The attenuation gain of the specific frequency band in notch filter processing is varied in accordance with the volume level and the attenuation gain of the specific frequency band in the notch filter processing to a delayed sound signal is gradually varied in accordance with the volume level of the sound signal during a delay period by a sound buffer 23a. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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