US 8,619,010 B2Granted

Image display device and image display method

AssigneeSharp Kabushiki Kaisha

InventorYuji Tanaka

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Abstract

In at least one embodiment of the present invention, display is performed with high color reproducibility by a display device that performs area active drive. An LED output value calculating unit obtains LED data representing the luminances upon light emission of LEDs provided for respective areas, based on an input image. A display luminance calculating unit calculates a luminance image including display luminances for the respective areas, based on the LED data and a luminance spread filter. An LCD data calculating unit determines temporary light transmittances of display elements of a liquid crystal panel based on an input image delayed by a frame memory and the luminance image, and obtains liquid crystal data representing light transmittances such that, when a highest value of temporary light transmittances for respective colors exceeds 1, values obtained by dividing each of the temporary light transmittances by the highest value are used as light transmittances, and when the highest value does not exceed 1, the temporary light transmittances are used as light transmittances. By this, even if there is a color with insufficient luminance, since the ratio between the colors does not change, color reproducibility increases.

Claims8

Dependent claims

An image display device having a function of controlling a luminance of a backlight, the image display device comprising:

a backlight including a plurality of light sources that emit lights which are a plurality of primary colors;
a display panel including a plurality of sets of a plurality of display elements, each set displaying one pixel in a plurality of colors by allowing lights from the light sources to be transmitted therethrough;
a light-emission luminance calculating unit that divides an input image into a plurality of areas and obtains light-emission luminance data based on the input image, the input image including a plurality of pixels, each of which is formed by a plurality of colors, the light-emission luminance data representing luminances upon light emission of the light sources provided for the respective areas;
a display luminance calculating unit that determines display luminances based on the light-emission luminance data for the respective areas, the display luminances being highest luminances obtained by the respective display elements;
a display data calculating unit that obtains display data for controlling light transmittances of the display elements, based on the input image and the display luminances determined by the display luminance calculating unit;
a panel drive circuit that outputs, based on the display data, signals for controlling the light transmittances of the display elements to the display panel;
and
a backlight drive circuit that outputs, based on the light-emission luminance data, signals for controlling luminances of the light sources to the backlight, wherein
when any of luminances for the respective colors forming a pixel in the input image is higher than a corresponding display luminance, the display data calculating unit obtains the display data based on values obtained by dividing each of the luminances for the respective colors forming the pixel in the input image by a same value, so that a light transmittance of a corresponding display element is 1 or less.

6 more elements

An image control display method for an image display device having a function of controlling a luminance of a backlight, and having a backlight including a plurality of light sources that emit lights which become a plurality of primary colors;

and a display panel including a plurality of sets of a plurality of display elements, each set displaying one pixel in a plurality of colors by allowing lights from the light sources to be transmitted therethrough, the method comprising:
a light-emission luminance calculating step of dividing an input image into a plurality of areas and obtaining light-emission luminance data based on the input image, the input image including a plurality of pixels, each of which is formed by a plurality of colors, the light-emission luminance data representing luminances upon light emission of the light sources provided for the respective areas;
a display luminance calculating step of determining display luminances based on the light-emission luminance data for the respective areas, the display luminances being highest luminances obtained by the respective display elements;
a display data calculating step of obtaining display data for controlling light transmittances of the display elements, based on the input image and the display luminances determined in the display luminance calculating step;
a panel driving step of causing the display panel to control the light transmittances of the display elements, based on the display data;
and
a backlight driving step of causing the backlight to control luminances of the light sources, based on the light-emission luminance data, wherein in the display data calculating step, when any of luminances for the respective colors forming a pixel in the input image is higher than a corresponding display luminance, the display data is obtained based on values obtained by dividing each of the luminances for the respective colors forming the pixel in the input image by a same value, so that a light transmittance of a corresponding display element is 1 or less.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/737,369Filed 1 Jun 2009
Priority: JP 2008-2230611 Sep 2008
Published: US 2011/0115827 A119 May 2011
Granted: 31 Dec 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G09G 3/3426
Using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines:…
G09G 3/3413
Control of illumination source: details of control of colour illumination sources
G09G 2320/0646
For control of overall brightness: modulation of illumination source brightness and image signal correlated to each other
G09G 2320/0666
Adjustment of display parameters: for control of colour parameters, e.g. colour temperature