Liquid crystal display device achieving predetermined color temperature while preventing a shift in color tone by correcting blue luminance

• US 8,451,391 B2
• Filed: 09/20/2007
• Issued: 05/28/2013
• Est. Priority Date: 09/26/2006
• 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: Ueki, Shun, Nakamura, Kozo, Taguchi, Tokio, Miyazaki, Akiko
• Primary Examiner(s): Robinson, Mark
• Assistant Examiner(s): Jordan, Andrew
• Application Number:
  US12/442,733
• Publication Number:
  US 20100091032A1
• Time in Patent Office: 2,077 Days
• Field of Search: 345/590, 349106-109
• US Class Current: 349/33
• 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 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2340/10 Mixing of images, i.e. displayed pixel being the result of an operation, e.g. adding, on the corresponding input pixels
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/2074 using sub-pixels
• 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
• CPC Class Codes: G09G 5/026 Control of mixing and/or overlay of colours in general G09G5/022 and G09G5/024 take precedence

Abstract

A liquid crystal display device includes a liquid crystal display panel having a pixel defined by at least three sub-pixels including a blue sub-pixel, a backlight which emits, toward the liquid crystal display panel, light that brings a color temperature to a predetermined level when the pixel displays white, and a color tone correction circuit which corrects a color tone of a color displayed by the pixel. When the pixel displays a color containing at least one predetermined color component that is other than a white component and a blue component, the color tone correction circuit performs a correction to set a luminance of the blue sub-pixel lower than an original luminance.

Claims

1. A liquid crystal display device, comprising:

a liquid crystal display panel which includes a pixel defined by at least three sub-pixels including a blue sub-pixel;

a backlight arranged to emit, toward the liquid crystal display panel, light that brings a color temperature to a predetermined level when the pixel displays white; and

a color tone correction section arranged to correct a color tone of a color displayed by the pixel;

wherein

when the pixel displays a color containing at least one predetermined color component that is other than a white component and a blue component, the color tone correction section makes a correction to set a luminance of the blue sub-pixel lower than an original luminance; and

the luminance of the blue sub-pixel remains uncorrected whenever the color displayed by the pixel includes only the white component.

2. The liquid crystal display device according to claim 1, wherein the at least one predetermined color component is a magenta component or a cyan component.

3. The liquid crystal display device according to claim 1, wherein, when the pixel displays a color that contains only the blue component, or a color that contains only the white component and the blue component, the color tone correction section makes a correction to set the luminance of the blue sub-pixel lower than the original luminance.

4. The liquid crystal display device according to claim 1, wherein, when the pixel displays a color that contains only the blue component, or a color that contains only the white component and the blue component, the color tone correction section does not make a correction on the luminance of the blue sub-pixel and the luminance of the blue sub-pixel is equal to the original luminance.

5. The liquid crystal display device according to claim 1, wherein a maximum luminance of the blue sub-pixel that is set when the pixel displays an arbitrary color containing the at least one predetermined color component is lower than the luminance of the blue sub-pixel that is set when the pixel displays at least one of white and blue.

6. The liquid crystal display device according to claim 1, wherein the color tone correction section creates a corrected image signal that indicates luminances to be actually presented by the at least three sub-pixels, from an image signal that indicates original luminances of a red sub-pixel, a green sub-pixel, and the blue sub-pixel in a pixel that is formed only of the red sub-pixel, the green sub-pixel, and the blue sub-pixel.

7. The liquid crystal display device according to claim 6, wherein the color tone correction section includes:

a color component extracting unit arranged to extract a color component from a color of the pixel that is indicated by the image signal; and

a signal synthesizing unit which is arranged to create, based on the original luminance of the blue sub-pixel and the color component, the corrected image signal in a manner that makes the luminance to be actually presented by the blue sub-pixel lower than the original luminance.

8. The liquid crystal display device according to claim 1, wherein the at least three sub-pixels include a red sub-pixel and a green sub-pixel.

9. The liquid crystal display device according to claim 8, wherein the at least three sub-pixels further include a yellow sub-pixel.

10. The liquid crystal display device according to claim 9, wherein the color tone correction section sets a luminance of the yellow sub-pixel to a predetermined value.

11. The liquid crystal display device according to claim 8, wherein, when the pixel displays a color which is free of a yellow component and which contains at least one color component other than the yellow component, the color tone correction section makes a correction to set the luminance of the blue sub-pixel lower than the original luminance.

12. The liquid crystal display device according to claim 9, wherein the at least three sub-pixels further include a cyan sub-pixel.

13. The liquid crystal display device according to claim 12, wherein, when the pixel displays a color which is free of the yellow component and a cyan component and which contains at least one color component other than the yellow component and the cyan component, the color tone correction section makes a correction to set the luminance of the blue sub-pixel lower than the original luminance.

14. A liquid crystal display device comprising a pixel that is defined by at least three sub-pixels including a blue sub-pixel, wherein

a maximum luminance of the blue sub-pixel that is set when the pixel displays an arbitrary color containing at least one predetermined color component that is other than a white component and a blue component is lower than a luminance of the blue sub-pixel that is set when the pixel displays at least one of white and blue;

the luminance of the blue sub-pixel is corrected when the pixel displays a color containing the at least one predetermined color component that is other than the white component and the blue component; and

the luminance of the blue sub-pixel remains uncorrected whenever the color displayed by the pixel includes only the white component.

15. The liquid crystal display device according to claim 14, wherein the at least one predetermined color component is a magenta component or a cyan component.

16. The liquid crystal display device according to claim 14, wherein the at least three sub-pixels include a red sub-pixel and a green sub-pixel.

17. The liquid crystal display device according to claim 16, wherein the at least three sub-pixels further include a yellow sub-pixel.

18. The liquid crystal display device according to claim 17, wherein the at least three sub-pixels further include a cyan sub-pixel.

19. A liquid crystal display device comprising a pixel containing a red sub-pixel, a green sub-pixel, and a blue sub-pixel, wherein

a luminance of the blue sub-pixel that is set when the pixel displays magenta and a luminance of the blue sub-pixel that is set when the pixel displays cyan are lower than a luminance of the blue sub-pixel that is set when the pixel displays white;

the luminance of the blue sub-pixel is corrected when the pixel displays a color containing at least one predetermined color component that is other than a white component and a blue component; and

the luminance of the blue sub-pixel remains uncorrected whenever the color displayed by the pixel includes only the white component.

20. The liquid crystal display device according to claim 19, wherein the pixel further includes a yellow sub-pixel.

21. The liquid crystal display device according to claim 20, wherein the pixel further includes a cyan sub-pixel.