Matsushita Electric Industrial Co., Ltd.

Yasuhiro Kumamoto

Taro Funamoto

Katsuyuki Arimoto

Takahiro Kobayashi

Yoshihito Ohta

Wataru Machidori

Tetsuo Kariya

A backlight device is configured from a drive unit and a backlight. The backlight includes a first light source group and a second light source group. The drive unit drives one or more fluorescent lamps of the first light source group in response to a first synchronous signal, and drives one or more fluorescent lamps of the second light source group in response to a second synchronous signal. A phase difference between the first synchronous signal and the second synchronous signal is within a range greater than 60 degrees and smaller than 120 degrees, or a range greater than 240 degrees and smaller than 300 degrees.

Backlight device and display unit provided with it

An EPG extraction portion extracts EPG information; a program type decision portion decides the type of broadcast program using the extracted EPG information, and outputs a ratio modification signal to change the ratio of the image display interval to the black display interval according to the program type; a driving pulse generation portion generates a gate driver control signal which changes the write timing of a frequency-doubled image signal and frequency-doubled black display signal in one field interval, according to the ratio modification signal; and, a gate driver changes the write timing of the frequency-doubled image signal and frequency-doubled black display signal according to the gate driver control signal, to change the ratio of the image display interval to the black display interval.

Display apparatus and display apparatus drive method

A doubler part doubles frequencies of video signals. A drive control circuit generates, in response to a synchronizing signal outputted from the doubler part, PWM dimming frequency information such that a PWM dimming frequency f and a black display ratio B satisfy the relationships f&#x2267;25B+250 and B&#x3e;10, and provides such information to a PWM dimming signal generation circuit. In addition, the drive control circuit drives a gate driver and a source driver such that one frame period is divided into an image display period and a black display period. The PWM dimming signal generation circuit generates, in response to a synchronizing signal and the PWM dimming frequency information, a PWM dimming signal and provides the PWM dimming signal to a lighting circuit. The lighting circuit activates a backlight device with dimming, in response to the PWM dimming signal. This configuration reduces colored interference fringes in a liquid crystal display device resulting from the combination of a black insertion drive technique and a PWM dimming technique.

Liquid crystal display device

A liquid crystal display apparatus that uses a backlight for display includes a video signal time compression circuit for compressing a video signal in the time axis direction and outputting the time-compressed video signal, an LCD controller for driving a liquid crystal panel based on the time-compressed video signal, and a source driver and a gate driver. The liquid crystal display apparatus also includes a motion detection circuit for detecting the amount of motion of a display image based on the video signal, a PWM modulation pulse generation circuit for generating modulation pulses different in frequency according to the detection result from the motion detection circuit, and an inverter for lighting up the backlight based on the modulation pulses, to thereby enable reduction of image contour blurring in a moving image and reduction of flicker in a still image.

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Neyagawa, Japan

Yasuhiro Kumamoto