Illumination device and liquid crystal display device using the same
First Claim
1. A liquid crystal display device, comprising:
- 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.
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Abstract
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.
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Citations
5 Claims
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1. A liquid crystal display device, comprising:
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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. - View Dependent Claims (2, 3, 4, 5)
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Specification