LIQUID CRYSTAL DISPLAY DEVICE AND CONTROL METHOD THEREFOR

• US 20120206513A1
• Filed: 07/23/2010
• Published: 08/16/2012
• Est. Priority Date: 11/20/2009
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ueno, Tetsuya
• Granted Patent: US 8,872,743 B2
• Time in Patent Office: Days
• US Class Current: 345/697
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127

Abstract

The present invention provides a liquid crystal display device including a multiple primary color panel capable of improving the display quality in the vicinity of a monochromatic color, and a control method therefor. The present invention provides a liquid crystal display device that performs display by input thereto of image signals for three colors from outside. The liquid crystal display device includes a liquid crystal display panel and a backlight. A plurality of pixels each including picture elements of four colors or more are formed in a display region of the liquid crystal display panel. Each pixel includes picture elements of three colors, provided with color filters having colors corresponding to the respective colors of the image signals, and at least one picture element of other color(s), provided with a color filter having a color corresponding to a color other than the colors of the image signals. The light emission intensity of the backlight can be controlled in accordance with image signals input. The light emission intensity of the backlight when a monochromatic color or a color close to a monochromatic color is displayed in the display region is greater than the light emission intensity when white is displayed in the display region.

Claims

1. A liquid crystal display device that performs display by input thereto of image signals for three colors from outside,

the liquid crystal display device comprising a liquid crystal display panel and a backlight, wherein:

a plurality of pixels each including picture elements of four colors or more are formed in a display region of the liquid crystal display panel;

each pixel includes picture elements of three colors, provided with color filters having colors corresponding to the respective colors of the image signals, and at least one picture element of other color(s), provided with a color filter having a color corresponding to a color other than the colors of the image signals;

a light emission intensity of the backlight can be controlled in accordance with image signals input; and

the light emission intensity of the backlight when a monochromatic color or a color close to a monochromatic color is displayed in the display region is greater than the light emission intensity when white is displayed in the display region, provided that the term “

color close to a monochromatic color”

refers to a color when a picture element that transmits light of which components include the monochromatic color and that is included in the at least one picture element of other color(s) is set to a gradation other than a highest gradation, and a picture element that transmits the monochromatic color is set to a highest gradation.

2. The liquid crystal display device according to claim 1, wherein:

the backlight includes a plurality of lighting portions whose light emission intensities can be controlled independently of each other; and

the light emission intensity of any one of the lighting portions for a certain section of the display region when the monochromatic color or the color close to the monochromatic color is displayed in the section is greater than the light emission intensity when white is displayed in the section.

3. A liquid crystal display device that performs display by input thereto of image signals for three colors from outside,

the liquid crystal display device comprising a liquid crystal display panel, a backlight, and a backlight intensity determination circuit that determines a light emission intensity of the backlight for each frame, wherein:

a plurality of pixels each including picture elements of four colors or more are formed in a display region of the liquid crystal display panel;

each pixel includes picture elements of three colors, provided with color filters having colors corresponding to the respective colors of the image signals, and at least one picture element of other color(s), provided with a color filter having a color corresponding to a color other than the colors of the image signals;

a light emission intensity of the backlight can be controlled in accordance with image signals input;

the backlight intensity determination circuit includes;

a backlight light amount calculation circuit that converts image signals for three colors that are input from outside into signals for four colors or more that correspond to the colors of the picture elements and determines required minimum light emission intensities of the backlight for the respective pixels based on the signals for four colors or more, and

a maximum value distinguishing circuit that determines a largest light emission intensity among the required minimum light emission intensities; and

the backlight emits light with the light emission intensity determined by the maximum value distinguishing circuit.

4. The liquid crystal display device according to claim 3, wherein:

each of the image signals for three colors comprises gradation data; and

the backlight intensity determination circuit further includes;

a reverse gamma conversion circuit that subjects the image signals that comprise gradation data to reverse gamma conversion to generate image signals for three colors that comprise brightness data; and

a dividing circuit that divides the image signals for three colors that comprise brightness data by the largest light emission intensity.

5. The liquid crystal display device according to claim 3, wherein:

the backlight includes a plurality of lighting portions whose light emission intensities can be controlled independently of each other;

the maximum value distinguishing circuit determines a largest light emission intensity among the required minimum light emission intensities for the respective sections of the display region that correspond to the respective lighting portions; and

the backlight intensity determination circuit further includes a lighting pattern calculation circuit that adds brightness distributions on an irradiated surface of the panel when the lighting portions emit light with the required minimum light emission intensities.

6. The liquid crystal display device according to claim 3, wherein:

the backlight light amount calculation circuit is a first backlight light amount calculation circuit;

the maximum value distinguishing circuit is a first maximum value distinguishing circuit;

the backlight intensity determination circuit further includes;

a second backlight light amount calculation circuit that converts the image signals for three colors into signals for four colors or more corresponding to the colors of the picture elements using the light emission intensity determined by the first maximum value distinguishing circuit, and determines required minimum light emission intensities of the backlight for the respective pixels based on the signals for four colors or more, and

a second maximum value distinguishing circuit that determines a largest light emission intensity among the required minimum light emission intensities calculated by the second backlight light amount calculation circuit; and

the backlight emits light with the light emission intensity determined by the second maximum value distinguishing circuit.

7. A control method for a liquid crystal display device that performs display by input thereto of image signals for three colors from outside,

the liquid crystal display device comprising a liquid crystal display panel and a backlight, wherein:

a plurality of pixels each including picture elements of four colors or more are formed in a display region of the liquid crystal display panel;

each pixel includes picture elements of three colors, provided with color filters having colors corresponding to the respective colors of the image signals, and at least one picture element of other color(s), provided with a color filter having a color corresponding to a color other than the colors of the image signals; and

a light emission intensity of the backlight can be controlled in accordance with image signals input;

the control method including a backlight intensity determination step of determining a light emission intensity of the backlight for each frame, wherein;

the backlight intensity determination step includes;

(1) a step of converting image signals for three colors that are input from outside into signals for four colors or more that correspond to the colors of the picture elements, and determining required minimum light emission intensities of the backlight for the respective pixels based on the signals for four colors or more, and

(2) a step of determining a largest light emission intensity among the required minimum light emission intensities; and

the backlight emits light with the light emission intensity determined in the step (2).

8. The control method for a liquid crystal display device according to claim 7, wherein:

each of the image signals for three colors comprises gradation data; and

the backlight intensity determination step further includes;

(3) a step of subjecting the image signals that comprise gradation data to reverse gamma conversion to generate image signals for three colors that comprise brightness data, and

(4) a step of dividing the image signals for three colors that comprise brightness data by the largest light emission intensity.

9. The control method for a liquid crystal display device according to claim 7, wherein:

the backlight includes a plurality of lighting portions whose light emission intensities can be controlled independently of each other;

in the step (2), a largest light emission intensity among the required minimum light emission intensities is determined for the respective sections of the display region that correspond to the respective lighting portions; and

the backlight intensity determination step further includes (5) a step of adding brightness distributions on an irradiated surface of the panel when the lighting portions emit light with the required minimum light emission intensities.

10. The control method for a liquid crystal display device according to claim 7,

the backlight intensity determination circuit further including:

(6) a step of converting the image signals for three colors into signals for four colors or more corresponding to the colors of the picture elements using the light emission intensity determined in the step (2), and determining required minimum light emission intensities of the backlight for the respective pixels based on the signals for four colors or more, and

(7) a step of determining a largest light emission intensity among the required minimum light emission intensities calculated in the step (6);

wherein the backlight emits light with the light emission intensity determined in the step (7).