KR101046678B1 - Display and its driving method - Google Patents

Abstract

An object of the present invention is to provide an RGBW display that can improve the problem of color coordinate difference as the luminance ratio of the image signal input to the RGBW display and the color of the image actually displayed is changed.

The present invention uses the red, green, and blue input video signals for displaying red, green, and blue colors, respectively, and the indicator signal, a white output video signal for displaying white color, and a signal for generating a control signal. A generating unit; A signal controller configured to generate red, green, and blue output image signals by adjusting the red, green, and blue input image signals according to the indicator signal and the control signal; The present invention provides a display including an image display unit including red, green, blue, and white sub-pixels receiving the red, green, blue, and white output image signals.

The present invention generates R, G, and B output video signals by adjusting each of the R, G, and B input video signals to equalize the luminance ratio with respect to the color of the input video signal and the actual displayed image, thereby displaying them on the RGBW display. The image may be reduced to the extent that the color coordinate difference between the image displayed on the RGB display cannot be recognized.

Description

Display and driving method of the same             

1A shows an RGB display in which pixels are made up of R, G, and B subpixels.

FIG. 1B shows an RGBW display in which the pixel consists of R, G, B, and W subpixels. FIG.

2 is a schematic illustration of a conventional RGBW display.

3 illustrates a Macbeth chart.

4 schematically illustrates an RGBW display according to an embodiment of the invention.

5 is a view showing a liquid crystal panel as an image display unit of an RGBW display according to an embodiment of the present invention.

6 is a view showing a driver of an RGBW display according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

220: drive unit 230: signal conversion unit                 

241, 242: first and second signal region converter 250: signal generator

251: Indicator signal generator 252: White output image signal generator

253: control signal generation unit 260: signal control unit

270: signal controller 280: data driver

290: gate driver 300: signal input system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device and a driving method thereof, and more particularly to red, green for displaying a red color, a green color, a blue color, and a white color. The present invention relates to a display including a blue, white sub-pixel, and a driving method thereof.

As a widely used display, a television or a monitor such as a cathode ray tube (CRT) is used. Meanwhile, there is a need for a flat panel display having excellent characteristics such as thinness, light weight, and low power consumption. A liquid crystal display, a plasma display panel, and a field emission display have emerged. Various flat panel display devices such as a field emission display and an electroluminescent display (or electroluminescence display (ELD)) have been researched and developed.                         

A display as described above displays an image through a plurality of pixels arranged in a matrix form. In general, a display includes three subpixels of R (red), G (green), and B (blue). The image will be displayed.

On the other hand, in recent years, displays which further include W (white) sub-pixels in R, G and B sub-pixels have been used.

FIG. 1A shows an RGB display in which the pixel is made up of R, G, and B subpixels, and FIG. 1B shows an RGBW display in which the pixel is made up of R, G, B, and W subpixels.

As shown, the RGBW display further includes W subpixels as compared to the RGB display, so that the RGBW display has a brighter brightness than the RGB display.

2 is a diagram schematically showing a conventional RGBW display.

The signal converter 120 of the RGBW display 100 converts the Ri, Gi, and Bi input video signals to output Ro, Go, Bo, and Wo output video signals. Here, the Ri, Gi, Bi input video signals correspond to the video signals input to the RGB display.

The image display unit 110 of the RGBW display 100 receives the Ro, Go, Bo, and Wo output image signals to display an image. Here, the Wo output video signal generally has a minimum value of the Ri, Gi, and Bi input video signals. In such a case, the proportional relationship between the input image signal and the output image signal may not be the same in order to indicate the luminance ratio of the red, green, and blue colors.                         

That is, the proportional relation between input video signals (Ri: Gi: Bi) and the proportional relation between output video signals (Ro + Wo: Go + Wo: Bo + Wo) to express the luminance of red, green, and blue colors May not be identical to each other.

In such a case, the luminance ratios of red, green, and blue appear differently in the image of the RGBW display and the RGB display, so that the RGBW display cannot display the image as desired.

Japanese Laid-Open Patent Publication No. 2001-147666 (published on May 29, 2001) discloses an RGBW liquid crystal display device displaying an image having the same luminance ratio as red, green, and blue colors as the RGB liquid crystal display device. In the RGBW liquid crystal display device disclosed in Japanese Patent Laid-Open No. 2001-14766,

Ri: Gi: Bi = Ro + Wo: Go + Wo: Bo + Wo

As described above, the luminance ratios of the red, green, and blue colors of the input video signal and the output video signal are the same.

The input video signal and the output video signal are digital values, and the luminance to color ratios can be equally adjusted according to arithmetic operations of the digital values. However, depending on the characteristics of the liquid crystal display, the luminance ratio with respect to the color of the image actually displayed may not be the same.

TABLE 1

Color Driving algorithm First algorithm Second algorithm Third algorithm dark skin (# 1) 0.014 0.008 0.014 light skin (# 2) 0.014 0.003 0.010 blue sky (# 3) 0.013 0.007 0.006 foliage (# 4) 0.008 0.004 0.012 blue flower (# 5) 0.015 0.003 0.006 bluish green (# 6) 0.007 0.002 0.005 orange (# 7) 0.007 0.019 0.020 purplish blue (# 8) 0.019 0.010 0.011 moderate red (# 9) 0.027 0.005 0.022 purple (# 10) 0.012 0.005 0.012 yellow green (# 11) 0.006 0.005 0.010 orange yellow (# 12) 0.005 0.013 0.013 blue (# 13) 0.016 0.004 0.012 green (# 14) 0.012 0.002 0.014 red (# 15) 0.018 0.004 0.025 yellow (# 16) 0.003 0.007 0.008 magenta (# 17) 0.014 0.009 0.017 cyan (# 18) 0.000 0.001 0.001 white (# 19) 0.004 0.003 0.003 neutral 8 (# 20) 0.001 0.001 0.001 neutral 6.5 (# 21) 0.001 0.000 0.000 neutral 5 (# 22) 0.001 0.001 0.001 neutral 3.5 (# 23) 0.000 0.001 0.001 black (# 24) 0.000 0.002 0.002 Maximum 0.027 0.019 0.025 Minimum 0.000 0.000 0.000 Average 0.009 0.005 0.009 Deviation 0.007 0.004 0.007

Table 1 shows a color coordinate difference according to whether a white subpixel is used or not in a conventional RGBW liquid crystal display using a Macbeth chart of FIG. 3. There are a large number of colors with a color coordinate difference of more than 0.02 in general. Such a color coordinate difference corresponds to a degree that can be generally recognized by a person.

Therefore, even if the video signal composed of digital values in the RGBW liquid crystal display is converted so that the luminance ratio for the color is the same, the luminance ratio for the color of the actually displayed image is different from the RGB liquid crystal display.

This phenomenon occurs because the individual characteristics of each subpixel change according to the type and thickness of the liquid crystal, the color filter, and the area ratio between the subpixels used in the RGBW liquid crystal display.

Therefore, even though the luminance ratios of the colors of the input image signal and the output image signal are arithmetically identical, the luminance ratio of the input image signal and the color of the image actually displayed may be different.

TABLE 2

Red Green blue R, G, B subpixel 6.80E-03 6.30E-03 9.60E-03 R, G, B, W subpixel 7.60E-03 6.90E-03 1.04E-02 Luminance contribution 1.12 1.10 1.08

Table 2 shows the degree of contribution to the luminance of the red, green, and blue colors of the W sub-pixels in the conventional RGBW liquid crystal display. Here, the RGBW liquid crystal display device operates in an IPS (In-Plane Switching) mode and uses a 72% Gamut color filter.

When the W subpixel is further added, the luminance of the red, green, and blue colors is increased by 1.12, 1.10, and 1.08 times, respectively, compared to the case of using only the R, G, and B subpixels.

Therefore, the luminance ratio with respect to the color of the image displayed in the RGBW liquid crystal display is different from the luminance ratio with respect to the color of the image displayed in the RGB liquid crystal display.

For example, in the RGBW liquid crystal display device disclosed in Japanese Patent Laid-Open No. 2001-14766, when the input image signal Ri, Gi, Bi = (158, 95, 73), the output image signal is (Ro, Go , Bo, Wo) = (158, 65, 33, 73)

Ri: Gi: Bi = Ro + Wo: Go + Wo: Bo + Wo = 1: 0.6: 0.46

This results in the same luminance ratio with respect to the color of the video signal.                         

However, since the luminance of red, green, and blue of an image increases by 1.12, 1.10, and 1.08 times, respectively, by adding a white sub-pixel, the luminance ratio of red, green, and blue of an actually displayed image is 1: 0.61: 0.48.

Therefore, the image displayed in the RGBW liquid crystal display device has a luminance ratio with respect to the color and the image displayed in the RGB liquid crystal display device, resulting in a color coordinate difference.

On the other hand, the above problem occurs not only in the RGBW liquid crystal display device, but also in the RGBW display.

An object of the present invention for solving the above problems is to provide an RGBW display that can improve the problem that the color coordinate difference occurs as the luminance ratio of the image signal input to the RGBW display and the color of the actual displayed image is changed. Is in.

In order to achieve the object as described above, the present invention, using the red, green, blue input image signals for displaying the red, green, blue colors, respectively, the white signal for displaying the indicator signal, and the white color A signal generator for generating an image signal and a control signal; A signal controller configured to generate red, green, and blue output image signals by adjusting the red, green, and blue input image signals according to the indicator signal and the control signal; Provided is a display including an image display unit including red, green, blue, and white sub-pixels receiving the red, green, blue, and white output image signals, respectively.

The signal generator may include an indicator signal generator configured to generate the indicator signal using the red, green, and blue input image signals; A white output image signal generation unit configured to generate the white output image signal using the indicator signal; And a control signal generator configured to generate the control signal using the white output image signal.

The indicator signal includes first and second indicator signals, wherein the first indicator signal is a maximum value of the red, green and blue input image signals, and the second indicator signal is the red, green and blue input image signals. A mean value may be selected from among a minimum value, a geometric mean value, and a harmonic mean value.

The control signal includes first, second, and third control signals, and the first, second, and third control signals use first, second, and third luminance contribution coefficients and white output image signals according to optical characteristics of the display, respectively. Relationship, Wr = Gr * Wo, Wg = Gg * Wo, Wb = Gb * Wo, Wr, Wg, Wb are the first, second, and third control signals, respectively, and Gr, Gg, Gb are each 1, 2, and 3 may be luminance contribution coefficients, and Wo may be a white output image signal.

The signal control unit is a relational expression using the first, second, and third control signals and the first indicator signal, Ro = Ri + Wr * Ri / I1-Wr, Go = Gi + Wg * Gi / I1-Wg, Bo = The red, green, and blue output video signals are generated by adjusting the red, green, and blue input video signals according to Bi + Wb * Bi / I1-Wb, and Ri, Gi, and Bi are red, green, and blue, respectively. The input image signal, Ro, Go, and Bo may be a red, green, and blue output image signal, respectively, and I1 may be a first indicator signal.                     

The white output image signal generation unit generates a white output image signal according to a function using the second indicator signal, Wo = f (I 2), and the function is determined according to an input selection signal, and I 2 is a second indicator signal. Wo may be a white output image signal.

The image display unit is a liquid crystal panel, and the first, second, and third luminance contribution coefficients represent an area ratio between the color filter type and thickness of the liquid crystal panel, the liquid crystal type and mode, and the red, green, blue, and white subpixels. It may be determined according to the optical properties to include.

The color coordinate difference between the image represented by the red, green, and blue input image signals and the image represented by the red, green, blue and white output image signals may be 0.02 or less.

In another aspect, the present invention, by using the red, green, blue input video signal for displaying the red, green, blue color indicator signal, the white output video signal for displaying white color, and the control signal A signal generation step of generating; A signal adjusting step of generating red, green, and blue output image signals by adjusting the red, green, and blue input image signals according to the indicator signal and the control signal; A display driving method includes an image display step of displaying an image through red, green, blue, and white sub-pixels receiving the red, green, blue, and white output image signals, respectively.

The signal generation step may include: an indicator signal generation step of generating the indicator signal using the red, green, and blue input image signals; A white output image signal generation step of generating the white output image signal using the indicator signal; And a control signal generation step of generating the control signal using the white output image signal.                     

The indicator signal includes first and second indicator signals, wherein the first indicator signal is a maximum value of the red, green and blue input image signals, and the second indicator signal is the red, green and blue input image signals. A mean value may be selected from among a minimum value, a geometric mean value, and a harmonic mean value.

The control signal includes first, second, and third control signals, and the first, second, and third control signals use first, second, and third luminance contribution coefficients and white output image signals according to optical characteristics of the display, respectively. Relationship, Wr = Gr * Wo, Wg = Gg * Wo, Wb = Gb * Wo, Wr, Wg, Wb are the first, second, and third control signals, respectively, and Gr, Gg, Gb are each 1, 2, and 3 may be luminance contribution coefficients, and Wo may be a white output image signal.

The signal control step is a relational expression using the first, second, third control signal and the first indicator signal, Ro = Ri + Wr * Ri / I1-Wr, Go = Gi + Wg * Gi / I1-Wg, Bo = Bi + Wb * Bi / I1-Wb to adjust the red, green, and blue input video signals to generate the red, green, and blue output video signals, wherein Ri, Gi, and Bi are red, green, and A blue input video signal, Ro, Go, and Bo may be a red, green, and blue output video signals, and I1 may be a first indicator signal.

The display is a liquid crystal display, and the first, second, and third luminance contribution coefficients are an area ratio between the color filter type and thickness of the liquid crystal display, the liquid crystal type and mode, and the red, green, blue, and white subpixels. It may be determined according to the optical properties including.

The color coordinate difference between the image represented by the red, green, and blue input image signals and the image represented by the red, green, blue and white output image signals may be 0.02 or less.

The present invention adjusts each of the R, G, and B input image signals by using an adjustment signal reflecting optical characteristics of the RGBW display so that the luminance ratio of the input image signal and the color of the image actually displayed is substantially the same. , G, B output video signal is generated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

4 is a diagram schematically illustrating an RGBW display according to an embodiment of the present invention. 5 illustrates a liquid crystal panel as an image display unit of an RGBW display according to an exemplary embodiment of the present invention, and FIG. 6 illustrates a driving unit of an RGBW display according to an exemplary embodiment of the present invention.

As illustrated, the display 200 includes an image display unit 210 and a driver 220.

The image display unit 210 includes R, G, B, and W subpixels for displaying red, green, blue, and white colors, respectively, and each of the R, G, B, and W subpixels includes one pixel ( P) is achieved. The R, G, B, and W sub-pixels receive the R, G, B, and W image signals output through the driver 220, respectively, and display corresponding colors. The data wirings and the gate wirings DL and GL, which cross each other, transfer the image signal and the scan signal to the subpixels, respectively.

In the case where a liquid crystal display device is used as the display 200, the liquid crystal panel 211 shown in FIG. 5 is used as the image display unit 210. The liquid crystal panel 211 is filled with a liquid crystal (not shown) between two substrates (not shown) facing each other, and displays an image by an electric field applied to the liquid crystal. The liquid crystal panel 211 includes a thin film transistor T positioned at a portion where data wirings and gate wirings DL and GL intersect each other to define sub-pixels, and data data and gate wirings DL and GL intersect each other. The liquid crystal capacitor C _LC is connected to the thin film transistor T.

The driver 220 includes a signal converter 230, a signal controller 270, a data driver, and gate drivers 280 and 290.

The signal converter 230 includes first and second signal region converters 241 and 242, a signal generator 250, and a signal controller 260.

The first signal region converter 241 converts the signal region of the image signal. The first signal region converter 241 converts the source image signals Rs, Gs and Bs of the L ^* signal region output from the signal input system 300 into the input image signals Ri, Gi, Bi of the Y signal region. Converted to and transmitted to the signal generator 250.

The first signal region converter 241,

L ^* = 116 (Y / Y _n ) ¹ /3-16

The source video signals Rs, Gs, and Bs can be converted into the input video signals Ri, Gi, and Bi according to the first signal region conversion equation, which is an inverse function of. Here, the image signal of the L ^* signal region is a signal related to the brightness (brightness) or brightness of light that a human feels, and the image signal of the Y signal region is a signal related to luminance (luminance) felt by the measuring machine. And, Y _n is a reference luminance for normalizing the video signal of the Y signal region to the video signal of the L ^* signal region, and corresponds to the luminance of the light source when a non-light emitting display is used. In the display, this corresponds to the maximum brightness and in the signal area to the maximum signal level.

The first signal region changer 241

Y = (L ^* ) ^γ

A second signal region conversion equation such as can be used. Is the gamma value of the display.

In particular, the first signal region converter 241 may use a look-up table (LUT) for efficient conversion of an image signal. The LUT consists of a table in which the output signals corresponding to the input signals are calculated in advance according to the first and second signal region conversion equations. Ri, Gi, Bi) are output.

The signal generator 250 generates various signals using the input image signals Ri, Gi, and Bi. The signal generator 250 includes an indicator signal generator 251, a white output image signal generator 252, and a control signal generator 253.

Pilot signal generating unit 251 is for receiving an input video signal (R _i, G _i, B _i) outputting a first and second indicator signals (I1, I2).

The first indicator signal I1 is

I1 = MAX = Max (Ri, Gi, Bi)

As such, a maximum signal MAX having a maximum value among the input image signals Ri, Gi, and Bi may be used. The first indicator signal I1 is input to the signal controller 260 to adjust the input image signals Ri, Gi, and Bi.

The second indicator signal I2 is

I2 = MIN = Min (Ri, Gi, Bi) or

I2 = (Ri * Gi * Bi) ^k1 or (k1 is a real number),

I2 = k2 * (Ri * Gi * Bi) / ((Ri * Gi) + (Gi * Bi) + (Ri * Bi)) (k2 is a positive real number)

As described above, a minimum signal MIN having a minimum value among the input image signals Ri, Gi, and Bi, and an average signal having a geometric or harmonic mean value may be used. Here, 3 may be used for k1 and k2.

The white output image signal generation unit 252 generates the white output image signal Wo by the white image signal output function Wo = f (I 2) using the second indicator signal I 2. Here, the white image signal output function is determined according to the selection signal SEL input from the outside.                     

In particular, the white output image signal generator 252 may use a plurality of LUTs and multiplexers (MUXs) corresponding to the white image signal output function to efficiently generate the white output image signal (Wo).

The control signal generator 253 receives the white output image signal (Wo) to generate a control signal. The control signal is composed of the first, second and third control signals Wr, Wg and Wb. The first, second and third control signals Wr, Wg and Wb are Ri, Gi and Bi, respectively. Used to adjust each input video signal.

The first, second and third control signals Wr, Wg and Wb are respectively,

Wr = Gr * Wo,

Wg = Gg * Wo,

Wb = Gb * Wo

Can be generated as Here, Gr, Gg, and Gb correspond to the first, second and third luminance contribution coefficients, respectively, and are determined according to the optical characteristics of the display. For example, in the case of using a liquid crystal display device, the luminance contribution coefficient has various values depending on the optical characteristics of the liquid crystal display device such as the type and thickness of the color filter, the type and mode of the liquid crystal, and the area ratio between the subpixels. .

The signal controller 260 adjusts the input image signals Ri, Gi, and Bi using the indicator signals and the control signals generated by the signal generator 250 to generate the output image signals Ro, Go, and Bo. Done.                     

Signal control unit 260,

Ro = Ri + Wr * Ri / I1-Wr,

Go = Gi + Wg * Gi / I1-Wg,

Bo = Bi + Wb * Bi / I1-Wb

According to the signal control relation as described above, the output signal signals Ro, Go, and Bo are generated by using the first indicator signal I1 and the control signals Wr, Wg, and Wb.

The signal controller 260 adjusts the input image signals Ri, Gi, and Bi appropriately by using control signals reflecting the optical characteristics of the display. The input image signals Ri, Gi, and Bi are actually output. The output image signals Ro, Go, and Bo are output by adjusting the input image signals Ri, Gi, and Bi so that the luminance ratio with respect to the color is substantially the same.

The output image signals Ro, Go, Bo, and Wo generated by the signal controller 260 and the white output image signal generator 252 are converted by the second signal region converter 242.

The second signal region converter 242 converts the output image signals Ro, Go, Bo, and Wo of the Y signal region into output image signals Ro`, Go`, Bo`, and Wo` of the L ^* signal region. The signal is transferred to the signal controller 270.

The second signal region conversion unit 242,

L ^* = 116 (Y / Y _n ) ¹ /3-16

According to the third signal region conversion equation as described above, the signal regions of the output image signals Ro, Go, Bo, and Wo may be converted.                     

And, the second signal region converter 242,

L ^* = (Y) ^{1 / γ}

A fourth signal region conversion equation such as can be used.

In particular, the second signal region converter 242 may use the LUT for efficient conversion of the image signal.

The signal controller 270 outputs the output image signals Ro`, Go`, Bo`, and Wo` having the signal region converted to the data driver 280 according to timing. The signal controller 270 outputs various control signals for controlling the data driver 280 and the gate driver 290.

According to the control signal, the data driver 280 outputs the output image signal to the R, G, B, and W subpixels of the image display unit 210, and the output image signal is transmitted to the subpixel through the data wiring DL. do. The gate driver 290 outputs the scan signal to the gate line GL. The sub-pixel connected to the gate line GL to which the gate signal in the on state is transmitted is turned on to receive the output image signal.

On the other hand, when using the liquid crystal display, the data driver 280 may further include a gray voltage generator (not shown) for providing a voltage (V ₁ ~ V _i ) corresponding to the i- gray scale. For example, when the output image signal is 8 bits, the gray voltage generator 220 generates 256 gray voltages V ₁ to V ₂₅₆ corresponding to 2 ⁸ . In addition, when using a liquid crystal display device, it may further include a light source (not shown), such as a lamp for supplying light to the liquid crystal panel (see 211 of FIG. 5).

TABLE 3

Color Driving algorithm First algorithm Second algorithm Third algorithm dark skin (# 1) 0.003 0.003 0.004 light skin (# 2) 0.001 0.001 0.002 blue sky (# 3) 0.001 0.003 0.003 foliage (# 4) 0.003 0.002 0.002 blue flower (# 5) 0.003 0.007 0.008 bluish green (# 6) 0.000 0.004 0.004 orange (# 7) 0.000 0.002 0.002 purplish blue (# 8) 0.004 0.007 0.006 moderate red (# 9) 0.002 0.004 0.003 purple (# 10) 0.002 0.001 0.000 yellow green (# 11) 0.000 0.001 0.001 orange yellow (# 12) 0.000 0.002 0.002 blue (# 13) 0.001 0.005 0.005 green (# 14) 0.002 0.002 0.002 red (# 15) 0.001 0.002 0.002 yellow (# 16) 0.000 0.001 0.001 magenta (# 17) 0.001 0.004 0.003 cyan (# 18) 0.000 0.000 0.000 white (# 19) 0.004 0.004 0.004 neutral 8 (# 20) 0.004 0.003 0.003 neutral 6.5 (# 21) 0.002 0.003 0.003 neutral 5 (# 22) 0.001 0.002 0.002 neutral 3.5 (# 23) 0.001 0.002 0.003 black (# 24) 0.001 0.001 0.001 Maximum 0.004 0.007 0.008 Minimum 0.000 0.000 0.000 Average 0.002 0.003 0.003 Deviation 0.001 0.002 0.002

Table 3 shows a color coordinate difference according to whether a white subpixel is used in an RGBW liquid crystal display as an RGBW display according to an exemplary embodiment of the present invention using the Macbeth chart of FIG. 3. For all colors, the color coordinate difference corresponds to 0.02 or less, and this color coordinate difference corresponds to a degree that is not usually recognized by a person.

Therefore, in the RGBW liquid crystal display according to the embodiment of the present invention, the luminance ratio with respect to the color of the input image signal and the image actually displayed is substantially the same.

The present invention generates R, G, and B output video signals by adjusting each of the R, G, and B input video signals so that the luminance ratio of the video signal input from the RGBW display and the color of the image actually displayed is substantially the same. . Therefore, the image displayed on the RGBW display is reduced to an unrecognizable degree from the image coordinate displayed on the RGB display.

In addition, the present invention adjusts the input image signal according to the optical characteristics of the RGBW display. Therefore, even for various RGBW displays having different optical characteristics, the image and color coordinate difference displayed in the RGB display are reduced to an unrecognizable degree.

Embodiment of the present invention as described above, as an example of the present invention, it is possible to change freely. It is apparent to those skilled in the art that such modifications fall within the scope of the present invention within the scope included in the spirit of the present invention.

The present invention generates R, G, and B output video signals by adjusting the R, G, and B input video signals so that the luminance ratio of the video signal input from the RGBW display and the color of the image actually displayed is the same. Therefore, the image displayed on the RGBW display can be reduced to the extent that the color coordinate difference between the image displayed on the RGB display cannot be recognized.

In addition, the present invention adjusts the input image signal according to the optical characteristics of the RGBW display. Therefore, even for various RGBW displays having different optical characteristics, there is an effect that the image displayed on the RGB display and the color coordinate difference can be reduced to an unrecognizable degree.

Claims (15)

A signal generator for generating an indicator signal, a white output image signal for displaying a white color, and a control signal using red, green, and blue input image signals for displaying red, green, and blue colors, respectively; A signal controller configured to generate red, green, and blue output video signals by adjusting the red, green, and blue input video signals according to the indicator signal and the control signal; An image display unit including red, green, blue, and white sub-pixels receiving the red, green, blue, and white output image signals, respectively; The signal generation unit, An indicator signal generator configured to generate the indicator signals using the red, green, and blue input image signals; A white output image signal generation unit configured to generate the white output image signal using the indicator signal; And a control signal generator configured to generate the control signal using the white output image signal. delete The method of claim 1, The indicator signal includes first and second indicator signals, The first indicator signal is a maximum value of the red, green, and blue input image signals, and the second indicator signal is selected from an average value including a minimum value, a geometric mean value, and a harmonic mean value of the red, green, and blue input image signals. display. The method of claim 3, wherein The control signal includes first, second, and third control signals, and the first, second, and third control signals use first, second, and third luminance contribution coefficients and white output image signals according to optical characteristics of the display, respectively. Relationship, Wr = Gr * Wo, Wg = Gg * Wo, Wb = Gb * Wo Has a value according to, Wr, Wg and Wb are first, second and third control signals, respectively. Gr, Gg, and Gb are first, second, and third luminance contribution coefficients, Wo is a white output video signal. The method of claim 4, wherein The signal control unit is a relational expression using the first, second, third control signal and the first indicator signal, Ro = Ri + Wr * Ri / I1-Wr, Go = Gi + Wg * Gi / I1-Wg, Bo = Bi + Wb * Bi / I1-Wb Generate the red, green, and blue output image signals by adjusting the red, green, and blue input image signals according to Ri, Gi, and Bi are red, green, and blue input video signals, respectively. Ro, Go, and Bo are red, green, and blue output video signals, respectively. Wherein I1 is a first indicator signal. The method of claim 3, wherein The white output image signal generation unit includes a function using the second indicator signal, Wo = f (I2) To generate a white output video signal, The function is determined according to the selection signal inputted, I2 is a second indicator signal and Wo is a white output video signal. The method of claim 4, wherein The image display unit is a liquid crystal panel, and the first, second, and third luminance contribution coefficients represent an area ratio between the color filter type and thickness of the liquid crystal panel, the liquid crystal type and mode, and the red, green, blue, and white subpixels. Display determined in accordance with the optical properties to include. The method of claim 1, And a color coordinate difference between the image represented by the red, green, and blue input image signals and the image represented by the red, green, blue and white output image signals is 0.02 or less. A signal generation step of generating an indicator signal, a white output image signal for displaying a white color, and a control signal using red, green, and blue input image signals for displaying red, green, and blue colors, respectively; A signal adjusting step of generating red, green, and blue output image signals by adjusting the red, green, and blue input image signals according to the indicator signal and the control signal; And an image display step of displaying an image through the red, green, blue, and white sub-pixels receiving the red, green, blue, and white output image signals, respectively. The signal generation step, An indicator signal generation step of generating the indicator signal using the red, green, and blue input image signals; A white output image signal generation step of generating the white output image signal using the indicator signal; And a control signal generation step of generating the control signal using the white output image signal. Display driving method. delete The method of claim 9, The indicator signal includes first and second indicator signals, The first indicator signal is a maximum value of the red, green, and blue input image signals, and the second indicator signal is selected from an average value including a minimum value, a geometric mean value, and a harmonic mean value of the red, green, and blue input image signals. Display driving method. The method of claim 11, The control signal includes first, second, and third control signals, and the first, second, and third control signals respectively output first, second, and third luminance contribution coefficients and white output image signals according to optical characteristics of the display. The relation used, Wr = Gr * Wo, Wg = Gg * Wo, Wb = Gb * Wo Has a value according to, Wr, Wg and Wb are first, second and third control signals, respectively. Gr, Gg, and Gb are first, second, and third luminance contribution coefficients, Wo is a display driving method of white output video signal. 13. The method of claim 12, The signal control step is a relational expression using the first, second, third control signal, and the first indicator signal, Ro = Ri + Wr * Ri / I1-Wr, Go = Gi + Wg * Gi / I1-Wg, Bo = Bi + Wb * Bi / I1-Wb Generate the red, green, and blue output image signals by adjusting the red, green, and blue input image signals according to Ri, Gi, and Bi are red, green, and blue input video signals, respectively. Ro, Go, and Bo are red, green, and blue output video signals, respectively. And I1 is a first indicator signal. 13. The method of claim 12, The display is a liquid crystal display, and the first, second, and third luminance contribution coefficients are an area ratio between the color filter type and thickness of the liquid crystal display, the liquid crystal type and mode, and the red, green, blue, and white subpixels. Display driving method is determined according to the optical characteristics comprising a. The method of claim 9, And a color coordinate difference between the image represented by the red, green, and blue input image signals and the image represented by the red, green, blue and white output image signals is 0.02 or less.

Images