# US 2013/0155091 A1 · Color Adjustment Device, Method for Adjusting Color and Display for the Same

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- Number: US 2013/0155091 A1
- Document ID: US20130155091A1
- Status: Published application
- Kind: A1
- Application number: 13/380,821
- Filed: 2011-12-19
- Published: 2013-06-20
- Earliest claimed: 2011-12-15
- Assignees: Shenzhen China Star Optoelectronics Technology Co., Ltd.
- Inventors: Ye Dai; Chihtsung Kang
- Web page: https://patentgrep.com/patent/US20130155091A1

## CPC

- H04N 9/64: Circuits for processing colour signals (H04N9/77 takes precedence; camera processing pipelines for processing colour signals H04N23/84)
- G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)}
- H04N 17/02: for colour television signals
- H04N 17/04: for receivers
- G09G 2320/0285: using tables for spatial correction of display data
- G09G 2320/0666: for control of colour parameters, e.g. colour temperature
- G09G 2360/145: the light originating from the display screen
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)

## Abstract

The present invention provides a color adjustment device, a method of adjusting color and a display device for the same. In the beginning, it measures a plurality of tristimulus sets at various white grayscales on a LCD panel, converts the multiple tristimulus sets into a plurality of chromatic sets (xn, yn). After then, among the plurality of chromatic sets (xn, yn), it recognizes the Pth chromatic set (xp, yp), the break point, and based on the pth chromatic set (xp, yp), determines a plurality of target chromatic sets (Nxn, Nyn) at from the grayscale 0 to the grayscale p, where Nx n = x 0 + ( x 255 - x 0 ) · [ 1 - exp  ( 1 - p n ) ] ,  Ny n = y 0 + ( y 255 - y 0 ) · [ 1 - exp  ( 1 - p n ) ] . By this method, an exponential function instead of a linear function is adopted to depict the chromatic variation at low grayscales. Thus the grayscale variation appears more smooth and without any obvious break point in human's perception.

## Claims

### Claim 1

A method of adjusting color, characterized in that: the method comprises:
measuring a plurality of tristimulus sets at various white grayscales on a LCD panel;
converting the plurality of tristimulus sets into a plurality of chromatic sets (xn, yn), where n=0, 1, 2, . . . , 255;
among the plurality of chromatic sets, judging a pth chromatic set (xp, yp) as a breakpoint, where xp−1−xp<0, xp−xp+1=0, yp−1−yp<0, yp−yp+1=0; and
based on the pth chromatic set (xp, yp), determining a plurality of target chromatic sets (Nxn, Nyn) at from the grayscale 0 to the grayscale p, where
Nx
n
=
x
0
+
(
x
255
-
x
0
)
·
[
1
-
exp

(
1
-
p
n
)
]
,

Ny
n
=
y
0
+
(
y
255
-
y
0
)
·
[
1
-
exp

(
1
-
p
n
)
]
,
n=0, 1, . . . , p and exp denotes to an exponential function.

### Claim 2 (depends on 1)

The method of claim 1, characterized in that: the method further comprises:
based on the pth chromatic set (xp, yp), determining a plurality of target chromatic sets (Nxn, Nyn) at from the grayscale p+1 to the grayscale 255 as (x255, y255).

### Claim 3 (depends on 2)

The method of claim 2, characterized in that: the method further comprises:
converting the plurality of sets of target luminance value WYn and target chromatic values (Nxn, Nyn) into a plurality of target tristimulus sets, each grayscale corresponding to one of the target tristimulus set, and each of the target tristimulus set comprising three target stimulus values;
determining a RGB ratios set corresponding to each of the target tristimulus set; and
before the LCD panel showing a predetermined grayscale, adjusting a RGB ratios set at the predetermined grayscale on the basis of the RGB ratios set of the target tristimulus set corresponding to the predetermined grayscale.

### Claim 4 (depends on 3)

The method of adjusting color of claim 3, the LCD panel comprising a plurality of pixels, each pixel comprising a plurality of sub-pixels for displaying red, green and blue, characterized in that the method further comprises:
based on the RGB ratios of the target stimulus set corresponding to the predetermined grayscale, adjusting driving voltages applied to the plurality of sub-pixels of each pixel.

### Claim 5

A color adjusting device, characterized in that: the color adjusting device comprises:
a measurement unit for measuring a plurality of tristimulus sets at various white grayscales on a LCD panel;
a first conversion unit, connected to the measurement unit, for converting the plurality of tristimulus sets into a plurality of chromatic sets (xn, yn), n=0, 1, 2, . . . , 255;
a judging unit, connected to the first conversion unit, for recognizing a pth chromatic set (xp, yp), that is, a break point, where xp−1−xp<0, xp−xp+1=0, yp−1−yp<0, yp−yp+1=0;
a determining unit, connected to the judging unit, for determining a plurality of target chromatic sets (Nxn, Nyn) at from the grayscale 0 to the grayscale p, where
Nx
n
=
x
0
+
(
x
255
-
x
0
)
·
[
1
-
exp

(
1
-
p
n
)
]
,

Ny
n
=
y
0
+
(
y
255
-
y
0
)
·
[
1
-
exp

(
1
-
p
n
)
]
,
n=0, 1, . . . , p, and exp denotes to an exponential function;
a second conversion unit, connected to the determining unit, for converting the plurality of target chromatic sets (Nxn, Nyn) into a plurality of target tristimulus sets, each grayscale corresponding to one of the target tristimulus set, and each target stimulus set comprising three stimulus values; and
a calculation unit, connected to the second conversion unit, for calculating a RGB ratios set corresponding to the tristimulus values of each target tristimulus set.

### Claim 6 (depends on 5)

The color adjustment device of claim 5, characterized in that: the color adjustment device further comprises a storage unit for storing all the RGB ratios sets corresponding to the target tristimulus sets produced by the calculation unit as a lookup table.

### Claim 7 (depends on 6)

The color adjustment device of claim 6, characterized in that: the color adjustment device further comprises an adjustment unit, connected to the storage unit, for obtaining the RGB ratios set of the target tristimulus set corresponding to a predetermined grayscale from the lookup table, and accordingly adjusting the RGB ratios set at the predetermined grayscale, before the LCD panel showing the predetermined grayscale.

### Claim 8 (depends on 5)

The color adjustment device of claim 5, characterized in that: the determining unit, based on the pth chromatic set (xp, yp), determines a plurality of target chromatic sets (Nxn, Nyn) at from the grayscale p+1 to the grayscale 255 as (x255, y255).

### Claim 9

A display comprising a liquid crystal display (LCD) panel, the LCD panel comprising a plurality of pixels for displaying an image, each pixel comprising a plurality of sub-pixels, characterized in that: the display further comprises a color adjustment device, the color adjustment device comprising:
a measurement unit for measuring a plurality of tristimulus sets at various white grayscales on a LCD panel;
a first conversion unit, connected to the measurement unit, for converting the plurality of tristimulus sets into a plurality of chromatic sets (xn, yn), n=0, 1, 2, . . . , 255;
a judging unit, connected to the first conversion unit, for recognizing a pth chromatic set (xp, yp), that is, a break point, where xp−1−xp<0, xp−xp+1=0, yp−1−yp<0, yp−yp+1=0;
a determining unit, connected to the judging unit, for determining a plurality of target chromatic sets (Nxn, Nyn) at from the grayscale 0 to the grayscale p, where
Nx
n
=
x
0
+
(
x
255
-
x
0
)
·
[
1
-
exp

(
1
-
p
n
)
]
,

Ny
n
=
y
0
+
(
y
255
-
y
0
)
·
[
1
-
exp

(
1
-
p
n
)
]
,
n=0, 1, . . . , p, and exp denotes to an exponential function;
a second conversion unit, connected to the determining unit, for converting the plurality of target chromatic sets (Nxn, Nyn) into a plurality of target tristimulus sets, each grayscale corresponding to one of the target tristimulus set, and each target stimulus set comprising three stimulus values; and
a calculation unit, connected to the second conversion unit, for calculating a RGB ratios set corresponding to the tristimulus values of each target tristimulus set.

### Claim 10 (depends on 9)

The display of claim 9, characterized in that: the color adjusting device further comprises a storage unit for storing all the RGB ratios corresponding to the white target tristimulus sets produced by the calculation unit as a lookup table.

### Claim 11 (depends on 10)

The display of claim 10, characterized in that: the color adjusting device further comprises an adjusting unit, connected to the storage unit, for obtaining the RGB ratios set of the target tristimulus set corresponding to the predetermined grayscale from the lookup table, and accordingly adjusting the RGB ratios set at the predetermined grayscale, before the LCD panel showing a predetermined grayscale.

### Claim 12 (depends on 11)

The display of claim 11, characterized in that: the display further comprises a driving unit coupled to the adjusting unit for adjusting driving voltage applied to the plurality of sub-pixels of each pixel according to the RGB ratios corresponding to the set of three target stimulus values at the predetermined grayscale.

### Claim 13 (depends on 9)

The display of claim 9, characterized in that: the determining unit, based on the pth chromatic set (xp, yp), determines a plurality of target chromatic sets (Nxn, Nyn) at from the grayscale p+1 to the grayscale 255 as (x255, y255).