Multiple primary color liquid crystal display device and signal conversion circuit

• US 9,324,286 B2
• Filed: 11/24/2009
• Issued: 04/26/2016
• Est. Priority Date: 11/28/2008
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Mori, Tomohiko, Tomizawa, Kazunari, Yoshida, Yuichi, Nakamura, Kozo, Ueki, Shun
• Primary Examiner(s): Kumar, Srilakshmi K
• Assistant Examiner(s): GUPTA, PARUL H
• Application Number:
  US13/131,289
• Publication Number:
  US 20110227965A1
• Time in Patent Office: 2,345 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0439 Pixel structures
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• CPC Class Codes: G09G 2300/0447 for multi-domain technique to improve the viewing angle in a liquid crystal display, such as multi-vertical alignment [MVA]
• 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 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• 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 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 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 5/026 Control of mixing and/or overlay of colours in general G09G5/022 and G09G5/024 take precedence
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables

Abstract

The viewing angle characteristics of a multiprimary liquid crystal display device in which a plurality of red subpixels are provided in each pixel are improved.

A multiprimary liquid crystal display device according to the present invention includes a pixel defined by a plurality of subpixels, and performs multicolor display by using four or more primary colors to be displayed by the plurality of subpixels. The plurality of subpixels of the multiprimary liquid crystal display device according to the present invention include first and second red subpixels R1 and R2 for displaying red, a green subpixel G for displaying green, a blue subpixel B for displaying blue, and a cyan subpixel C for displaying cyan. When a color having a hue which is within a predetermined first range is displayed by the pixel, the gray scale level of the first red subpixel R1 and the gray scale level of the second red subpixel R2 differ from each other. When a color having a hue which is within a second range different from the first range is displayed by the pixel, the gray scale level of the first red subpixel R1 and the gray scale level of the second red subpixel R2 are equal.

Claims

1. A multiprimary liquid crystal display device comprising a pixel defined by a plurality of subpixels, the multiprimary liquid crystal display device performing multicolor display by using four or more primary colors to be displayed by the plurality of subpixels, wherein,

the plurality of subpixels include first and second red subpixels for displaying red, a green subpixel for displaying green, a blue subpixel for displaying blue, and a cyan subpixel for displaying cyan, there being a greater number of red subpixels in the pixel than any other color of subpixels;

and

when a color having a hue within a predetermined first range is displayed by the pixel, a gray scale level of the first red subpixel and a gray scale level of the second red subpixel differ from each other, and

when a color having a hue within a second range which is different from the first range is displayed by the pixel, the gray scale level of the first red subpixel and the gray scale level of the second red subpixel are equal.

2. The multiprimary liquid crystal display device of claim 1, wherein the plurality of subpixels further include a yellow subpixel for displaying yellow.

4. The multiprimary liquid crystal display device of claim 1, comprising a multiprimary signal generation circuit for receiving an input video signal corresponding to three primaries and generating a multiprimary signal corresponding to four or more primary colors.

5. The multiprimary liquid crystal display device of claim 4, further comprising a red subpixel independent driving circuit for, depending on a hue of a color represented by the input video signal, determining the gray scale level of the first red subpixel and the gray scale level of the second red subpixel from a red component contained in the multiprimary signal.

6. The multiprimary liquid crystal display device of claim 5, wherein the red subpixel independent driving circuit uses a predetermined weight function to determine the gray scale level of the first red subpixel and the gray scale level of the second red subpixel.

7. The multiprimary liquid crystal display device of claim 6, wherein,

the weight function is designated as H;

gray scale levels of a red component, a green component, and a blue component contained in the input video signal are Rin, Gin, and Bin, respectively;

a normalized luminance represented by the red component contained in the multiprimary signal is Y(Rout); and

normalized luminances of the first red subpixel and the second red subpixel are Y(R1out) and Y(R2out), respectively, and

the weight function H is expressed as

H=(Rin−

Gin)/Rin in the case where Rin>

Gin>

Bin,

H=(Rin−

Bin)/Rin in the case where Rin>

Bin>

Gin, or

H=0 in any other case, and

the normalized luminance Y(R1out) of the first red subpixel and the normalized luminance Y(R2out) of the second red subpixel are expressed as

Y(R1out)=H×

Y(Rout) and

Y(R2out)=(2−

H)×

Y(Rout) in the case where (2−

H)×

Y(Rout)≦

1, or

Y(R1out)=2×

Y(Rout)−

1 and

Y(R2out)=1 in the case where (2−

H)×

Y(Rout)>

1.

8. The multiprimary liquid crystal display device of claim 1, wherein the multiprimary liquid crystal display device performs display in a vertical alignment mode.

3. A multiprimary liquid crystal display device comprising a pixel defined by a plurality of subpixels, the multiprimary liquid crystal display device performing multicolor display by using four or more primary colors to be displayed by the plurality of subpixels, wherein,

the plurality of subpixels include first and second red subpixels for displaying red, a green subpixel for displaying green, a blue subpixel for displaying blue, and a yellow subpixel for displaying yellow, there being a greater number of red subpixels in the pixel than any other color of subpixels;

and

when a color having a hue within a predetermined first range is displayed by the pixel, a gray scale level of the first red subpixel and a gray scale level of the second red subpixel differ from each other, and

when a color having a hue within a second range which is different from the first range is displayed by the pixel, the gray scale level of the first red subpixel and the gray scale level of the second red subpixel are equal.

14. The multiprimary liquid crystal display device of claim 3, comprising a multiprimary signal generation circuit for receiving an input video signal corresponding to three primaries and generating a multiprimary signal corresponding to four or more primary colors.

15. The multiprimary liquid crystal display device of claim 14, further comprising a red subpixel independent driving circuit for, depending on a hue of a color represented by the input video signal, determining the gray scale level of the first red subpixel and the gray scale level of the second red subpixel from a red component contained in the multiprimary signal.

16. The multiprimary liquid crystal display device of claim 15, wherein the red subpixel independent driving circuit uses a predetermined weight function to determine the gray scale level of the first red subpixel and the gray scale level of the second red subpixel.

17. The multiprimary liquid crystal display device of claim 16, wherein,

the weight function is designated as H;

gray scale levels of a red component, a green component, and a blue component contained in the input video signal are Rin, Gin, and Bin, respectively;

a normalized luminance represented by the red component contained in the multiprimary signal is Y(Rout);

and normalized luminances of the first red subpixel and the second red subpixel are Y(R1out) and Y(R2out), respectively, and

the weight function H is expressed as

H=(Rin−

Gin)/Rin in the case where Rin>

Gin>

Bin,

H=(Rin−

Bin)/Rin in the case where Rin>

Bin>

Gin, or

H=0 in any other case, and

the normalized luminance Y(R1out) of the first red subpixel and the normalized luminance Y(R2out) of the second red subpixel are expressed as

Y(R1out)=H×

Y(Rout) and

Y(R2out)=(2−

H)×

Y(Rout) in the case where (2−

H)×

Y(Rout)≦

1, or

Y(R1out)=2×

Y(Rout)−

1 and

Y(R2out)=1 in the case where (2−

H)×

Y(Rout)>

1.

18. The multiprimary liquid crystal display device of claim 3, wherein the multiprimary liquid crystal display device performs display in a vertical alignment mode.

9. A signal conversion circuit for use in a multiprimary liquid crystal display device having a pixel defined by a plurality of subpixels including first and second red subpixels for displaying red, a green subpixel for displaying green, a blue subpixel for displaying blue, and a cyan subpixel for displaying cyan, there being a greater number of red subpixels in the pixel than any other color of subpixels, the multiprimary liquid crystal display device performing multicolor display by using four or more primary colors to be displayed by the plurality of subpixels, the signal conversion circuit comprising:

a multiprimary signal generation circuit for receiving an input video signal corresponding to three primaries and generating a multiprimary signal corresponding to four or more primary colors; and

a red subpixel independent driving circuit for, depending on a hue of a color represented by the input video signal, determining the gray scale level of the first red subpixel and the gray scale level of the second red subpixel from a red component contained in the multiprimary signal.

11. The signal conversion circuit of claim 9, wherein the red subpixel independent driving circuit uses a predetermined weight function to determine the gray scale level of the first red subpixel and the gray scale level of the second red subpixel.

12. The signal conversion circuit of claim 11, wherein,

the weight function is designated as H;

gray scale levels of a red component, a green component, and a blue component contained in the input video signal are Rin, Gin, and Bin, respectively;

a normalized luminance represented by the red component contained in the multiprimary signal is Y(Rout); and

normalized luminances of the first red subpixel and the second red subpixel are Y(R1out) and Y(R2out), respectively, and

the weight function H is expressed as

H=(Rin−

Gin)/Rin in the case where Rin>

Gin>

Bin,

H=(Rin−

Bin)/Rin in the case where Rin>

Bin>

Gin, or

H=0 in any other case, and

the normalized luminance Y(R1out) of the first red subpixel and the normalized luminance Y(R2out) of the second red subpixel are expressed as

Y(R1out)=H×

Y(Rout) and

Y(R2out)=(2−

H)×

Y(Rout) in the case where (2−

H)×

Y(Rout)≦

1, or

Y(R1out)=2×

Y(Rout)−

1 and

Y(R2out)=1 in the case where (2−

H)×

Y(Rout)>

1.

13. A multiprimary liquid crystal display device comprising the signal conversion circuit of claim 9.

10. A signal conversion circuit for use in a multiprimary liquid crystal display device having a pixel defined by a plurality of subpixels including first and second red subpixels for displaying red, a green subpixel for displaying green, a blue subpixel for displaying blue, and a yellow subpixel for displaying yellow, there being a greater number of red subpixels in the pixel than any other color of subpixels, the multiprimary liquid crystal display device performing multicolor display by using four or more primary colors to be displayed by the plurality of subpixels, the signal conversion circuit comprising:

a multiprimary signal generation circuit for receiving an input video signal corresponding to three primaries and generating a multiprimary signal corresponding to four or more primary colors; and

a red subpixel independent driving circuit for, depending on a hue of a color represented by the input video signal, determining the gray scale level of the first red subpixel and the gray scale level of the second red subpixel from a red component contained in the multiprimary signal.

19. The signal conversion circuit of claim 10, wherein the red subpixel independent driving circuit uses a predetermined weight function to determine the gray scale level of the first red subpixel and the gray scale level of the second red subpixel.

20. The signal conversion circuit of claim 19, wherein,

the weight function is designated as H;

gray scale levels of a red component, a green component, and a blue component contained in the input video signal are Rin, Gin, and Bin, respectively;

a normalized luminance represented by the red component contained in the multiprimary signal is Y(Rout); and

normalized luminances of the first red subpixel and the second red subpixel are Y(R1out) and Y(R2out), respectively, and

the weight function H is expressed as

H=(Rin−

Gin)/Rin in the case where Rin>

Gin>

Bin,

H=(Rin−

Bin)/Rin in the case where Rin>

Bin>

Gin, or

H=0 in any other case, and

the normalized luminance Y(R1out) of the first red subpixel and the normalized luminance Y(R2out) of the second red subpixel are expressed as

Y(R1out)=H×

Y(Rout) and

Y(R2out)=(2−

H)×

Y(Rout) in the case where (2−

H)×

Y(Rout)≦

1, or

Y(R1out)=2×

Y(Rout)−

1 and

Y(R2out)=1 in the case where (2−

H)×

Y(Rout)>

1.

21. A multiprimary liquid crystal display device comprising the signal conversion circuit of claim 10.