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

• US 20110080520A1
• Filed: 05/21/2009
• Published: 04/07/2011
• Est. Priority Date: 05/27/2008
• Status: Abandoned Application

• 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, Yoshida, Yuichi, Tomizawa, Kazunari, Ueki, Shun, Nakamura, Kohzoh
• Application Number:
  US12/993,906
• Publication Number:
  US 20110080520A1
• Time in Patent Office: Days
• US Class Current: 348/453
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 2201/52 RGB geometrical arrangements
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• 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 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2300/0486 Cholesteric liquid crystals, including chiral-nematic liquid crystals, with transitions between focal conic, planar, and homeotropic states
• 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 2340/06 Colour space transformation
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• 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 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

There is provided a signal conversion circuit which is suitably used in a multiprimary liquid crystal display device (especially a multiprimary liquid crystal display device which performs display in a vertical alignment mode), and a multiprimary liquid crystal display device having such a signal conversion circuit.

A signal conversion circuit according to the present invention is for use in a multiprimary liquid crystal display device which performs display in a vertical alignment mode, 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 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 in a vertical alignment mode 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.

9. The multiprimary liquid crystal display device of claim 8, wherein,

the liquid crystal display panel includes a first substrate, a second substrate opposing the first substrate, a vertical-alignment type liquid crystal layer disposed between the first substrate and the second substrate, the liquid crystal display panel having a plurality of subpixels each displaying one of the four or more primary colors;

each of the plurality of subpixels includes a first electrode provided on the liquid crystal layer side of the first substrate, and a second electrode being provided on the second substrate and opposing the first electrode via the liquid crystal layer; and

in each of the plurality of subpixels, when a predetermined voltage is applied across the liquid crystal layer, a plurality of regions whose liquid crystal molecules tilt in respectively different azimuth directions are formed.

10. The multiprimary liquid crystal display device of claim 9, wherein

the liquid crystal display panel includes:

first orientation restriction means provided on the first electrode side of the liquid crystal layer; and

second orientation restriction means provided on the second electrode side of the liquid crystal layer.

11. The multiprimary liquid crystal display device of claim 10, wherein the first orientation restriction means is a rib, and the second orientation restriction means is a slit provided in the second electrode.

12. The multiprimary liquid crystal display device of claim 10, wherein the first orientation restriction means is a first rib, and the second orientation restriction means is a second rib.

13. The multiprimary liquid crystal display device of claim 10, wherein the first orientation restriction means is a first slit provided in the first electrode, and the second orientation restriction means is a second slit provided in the second electrode.

14. The multiprimary liquid crystal display device of claim 9, wherein,

the first electrode includes at least one aperture or recessed portion formed at a predetermined position;

and

in each of the plurality of subpixels, when a predetermined voltage is applied across the liquid crystal layer, a plurality of liquid crystal domains are formed each exhibiting an axisymmetric orientation.

4. A signal conversion circuit for use in a multiprimary liquid crystal display device which performs display in a vertical alignment mode 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.