SIGNAL CONVERSION CIRCUIT AND MULTIPLE PRIMARY COLOR LIQUID CRYSTAL DISPLAY DEVICE WITH THE CIRCUIT

• US 20100053235A1
• Filed: 11/20/2007
• Published: 03/04/2010
• Est. Priority Date: 11/28/2006
• 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: Mori, Tomohiko, Tomizawa, Kazunari, Ueki, Shun, Muroi, Takao
• Granted Patent: US 8,294,739 B2
• Time in Patent Office: Days
• US Class Current: 345/694
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 2201/52 RGB geometrical arrangements
• 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 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

Abstract

In one embodiment of the present invention, a signal conversion circuit is disclosed which is suitably used in a multiprimary liquid crystal display device, and a multiprimary liquid crystal display device having such a signal conversion circuit. A signal conversion circuit according to one embodiment of the present invention is for use in a multiprimary liquid crystal display device, and converts an input video signal to a multiprimary signal corresponding to four or more primary colors. When generating a multiprimary signal for displaying dark skin, the signal conversion circuit according to an embodiment of the present invention applies a conversion to the video signal so that a color difference Δu′v′=((u′−u₆₀′)²+(v′−v₆₀′)²) is 0.03 or less, the color difference Δu′v′ being defined by CIE1976 chromaticity coordinates (u′, v′) representing a chromaticity when the pixel is viewed from the frontal direction and CIE1976 chromaticity coordinates (u₆₀′, v₆₀′) representing a chromaticity when the pixel is viewed from a 60° oblique direction.

Claims

1. A signal conversion circuit for use in a multiprimary liquid crystal display device which performs display by using four or more primary colors, the signal conversion circuit converting an input video signal to a multiprimary signal corresponding to four or more primary colors, wherein

when generating a multiprimary signal for a pixel of the multiprimary liquid crystal display device to display dark skin according to the Macbeth chart, the signal conversion circuit applies a conversion to the video signal so that a color difference Δ

u′

v′

=((u′

−

u₆₀′

)²+(v′

−

v₆₀′

)²) is 0.03 or less, the color difference Δ

u′

v′

being defined by CIE1976 chromaticity coordinates (u′

, v′

) representing a chromaticity when the pixel is viewed from a frontal direction and CIE1976 chromaticity coordinates (u₆₀′

, v₆₀′

) representing a chromaticity when the pixel is viewed from a 60°

oblique direction.

2. The signal conversion circuit of claim 1, wherein the signal conversion circuit applies a conversion to a video signal so that the color difference Δ

u′

v′

is 0.008 or less when generating a multiprimary signal for the pixel of the multiprimary liquid crystal display device to display dark skin according to the Macbeth chart.

3. The signal conversion circuit of claim 1, wherein the signal conversion circuit applies a conversion to a video signal so that the color difference Δ

u′

v′

is 0.01 or less when generating a multiprimary signal for the pixel of the multiprimary liquid crystal display device to display light skin according to the Macbeth chart.

5. The signal conversion circuit of claim 3, wherein the signal conversion circuit applies a conversion to a video signal so that the color difference Δ

u′

v′

is 0.008 or less when generating a multiprimary signal for the pixel of the multiprimary liquid crystal display device to display light skin according to the Macbeth chart.

6. The signal conversion circuit of claim 1, wherein, when there is a number n of primary colors to be used for displaying, the signal conversion circuit acquires luminances of (n−

3) primary colors among the n primary colors by referring to a look-up table based on the input video signal, and calculates luminances of the remaining three primary colors among the n primary colors through a calculation using the luminances of the (n−

3) primary colors.

7. The signal conversion circuit of claim 6, comprising:

a look-up table memory for storing the look-up table; and

a calculation section for performing the calculation.

8. A multiprimary liquid crystal display device comprising:

the signal conversion circuit of claim 1; and

a liquid crystal display panel to which the multiprimary signal generated by the signal conversion circuit is input.

4. A signal conversion circuit for use in a multiprimary liquid crystal display device which performs display by using four or more primary colors, the signal conversion circuit converting an input video signal to a multiprimary signal corresponding to four or more primary colors, wherein

when generating a multiprimary signal for a pixel of the multiprimary liquid crystal display device to display light skin according to the Macbeth chart, the signal conversion circuit applies a conversion to the video signal so that a color difference Δ

u′

v′

=((u′

−

u₆₀′

)²+(v′

−

v₆₀′

)²) is 0.01 or less, the color difference Δ

u′

v′

being defined by CIE1976 chromaticity coordinates (u′

, v′

) representing a chromaticity when the pixel is viewed from a frontal direction and CIE1976 chromaticity coordinates (u₆₀′

, v₆₀′

) representing a chromaticity when the pixel is viewed from a 60°

oblique direction.

9. The signal conversion circuit of claim 4, wherein the signal conversion circuit applies a conversion to a video signal so that the color difference Δ

u′

v′

is 0.008 or less when generating a multiprimary signal for the pixel of the multiprimary liquid crystal display device to display light skin according to the Macbeth chart.

10. The signal conversion circuit of claim 4, wherein, when there is a number n of primary colors to be used for displaying, the signal conversion circuit acquires luminances of (n−

3) primary colors among the n primary colors by referring to a look-up table based on the input video signal, and calculates luminances of the remaining three primary colors among the n primary colors through a calculation using the luminances of the (n−

3) primary colors.

11. The signal conversion circuit of claim 10, comprising:

a look-up table memory for storing the look-up table; and

a calculation section for performing the calculation.

12. A multiprimary liquid crystal display device comprising:

the signal conversion circuit of claim 4; and

a liquid crystal display panel to which the multiprimary signal generated by the signal conversion circuit is input.