Sharp Kabushiki Kaisha Corporation

Masanori Nishido

Tetsuya Kobayashi

Yasutake Furukoshi

Toshihiro Suzuki

Tetsuya Hamada

Keiji Hayashi

Mari Sugawara

Koichi Katagawa

Katsuyoshi Hiraki

Fumiaki Yamada

A drive control circuit includes a timing controller for detecting a change of a horizontal scanning frequency, a gate voltage generating circuit for generating two kinds of gate-on voltages Va and Vb (Va&#x3c;Vb), and a switch for outputting one of the gate-on voltages Va and Vb from the gate voltage generating circuit in accordance with an output of the timing controller. The timing controller includes a counter for counting the number of clocks for one horizontal period, and a comparator for comparing a count result with a threshold value. When the horizontal scanning frequency is in a normal state, the low gate-on voltage Va is outputted, and when the horizontal scanning frequency exceeds a predetermined threshold value, that is, the count value falls below a threshold value, the high gate-on voltage Vb is outputted.

Driving method and drive control circuit of liquid crystal display device, and liquid crystal display device including the same

A liquid crystal display device including an LCD panel modulating light transmissivities of plural pixels disposed in a matrix form on the basis of respective gradation data; an illumination device for irradiating light to the respective pixels while a ratio (duty ratio) of a lighting time in one frame period is changed; and a display data conversion part for calculating respective lightnesses and a lightness histogram from the respective gradation data, determining a threshold lightness from the lightness histogram on the basis of a previously determined ratio of pixels to be saturated in brightness, processing the respective gradation data on the basis of the threshold lightness to output them to the LCD panel, and outputting duty ratio data to change the duty ratio to the illumination device.

Illumination device and liquid crystal display device using the same

A drive control circuit supplies a gate voltage so that display quality is not degraded even in a case where a vertical scanning frequency or a horizontal scanning frequency is changed. The circuit includes a timing controller for detecting a change of a horizontal scanning frequency, a gate voltage generating circuit for generating two kinds of gate-on voltages Va and Vb (Va&#x3c;Vb), and a switch for outputting one of the gate-on voltages Va and Vb from the gate voltage generating circuit in accordance with an output of the timing controller. The timing controller includes a counter for counting the number of clocks for one horizontal period, and a comparator for comparing a count result with a threshold value. When the horizontal scanning frequency is in a normal state, the low gate-on voltage Va is outputted, and when the horizontal scanning frequency exceeds a predetermined threshold value, that is, the count value falls below a threshold value, the high gate-on voltage Vb is outputted.

An illumination device is provided which can reduce a movement blur and a tailing phenomenon on a motion picture display while a drop in display brightness is suppressed, and which can suppress power consumption, can be made small and light, and can prolong the lifetime, and a liquid crystal display device using the same is provided. A light source control part of a control circuit synchronizes a latch pulse signal outputted from a gate driver control part to a gate driver, and outputs light emission control signals to respective light source power supply circuits. The respective light source power supply circuits change emission states of cold cathode fluorescent lamps to one of a first to a third emission states on the basis of the inputted light emission control signals, and illuminate an LCD panel from a rear surface of a display area. A first stage emission state is a non-lighting state, a second stage emission state is a maximum lighting state in which maximum lighting brightness is obtained, and a third emission state is an intermediate lighting state in which brightness of about one half of the second stage emission state is obtained.

Growing community of inventors

Kawasaki, Japan

Masanori Nishido