KR20130037538A - Apparatus and method for correcting color of display device - Google Patents

Abstract

PURPOSE: A color correction device and a correcting method thereof are provided to improve image quality by controlling chroma depending on the image condition in real time. CONSTITUTION: A color space conversion part(151) converts the input data of a trichromatic space into the corresponding color data of a corresponding color space. An OLED lookup table(161) stores the value of a boundary between the increase and decrease of chroma depending on the brightness components of the corresponding color data and the material properties of the OLED. A parameter adjustment part(170) calculates the parameters of the horizontal and vertical directions of the boundary value from the OLED look up table for setting a parameter determining the increase and decrease of chroma. [Reference numerals] (151) Color space conversion part; (153) Operation part; (155) Reverse color space conversion unit;

Description

Apparatus and method for color correction of display devices {APPARATUS AND METHOD FOR CORRECTING COLOR OF DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device and to a color correction device and method for reducing display power and improving image quality by adjusting saturation in real time according to image conditions.

Recently, organic light emitting diode (OLED) display devices, along with liquid crystal displays (LCDs), have emerged as image display devices. LCD displays images by using the electrical and optical characteristics of liquid crystals having anisotropy such as refractive index and dielectric constant, and realizes gradation by adjusting the light transmittance through which each pixel passes through the polarizing plate in the direction of the liquid crystal array according to the data signal. do. An OLED display is a self-luminous device that emits an organic light emitting layer by recombination of electrons and holes. The OLED display device has high brightness, low driving voltage, and ultra thin film. The OLED display implements gradation by adjusting the magnitude of the current supplied to the OLED pixel by the driving circuit of each pixel according to the data signal.

As image display apparatuses develop in the direction of high resolution and high definition, color reproducibility is improved. In particular, the OLED display device is a self-luminous device, which has advantages of better color expression than other display devices. In order to highlight these advantages, a technique capable of emphasizing color expression is required. Saturation can be adjusted to a high level by emphasizing the color expression, but if the saturation is too high, the viewer's eyes may be excessively stimulated to give a visually rejection reaction. In addition, when the saturation is adjusted, there should be no change in the hue, and in order to apply the method of adjusting the saturation to the display device, a simple operation capable of real-time processing is further required.

Furthermore, there is a method of emphasizing color expressiveness that adjusts general saturation to a higher level, and a sharpening method of adjusting a higher luminance and a lower luminance to a lower level. Since the power consumption is large, there was a problem that the overall power consumption increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color correction apparatus and method for a display device capable of reducing power consumption and improving image quality by adjusting chroma in real time according to image conditions.

A color correction device of a display device according to an embodiment of the present invention,

A color space converter for converting input data of three primary color spaces into corresponding color data of a corresponding color color space; An OLED lookup table for storing boundary values of increasing and decreasing saturation according to brightness components of the corresponding color data and material characteristics of the OLED; And a parameter adjusting unit that calculates parameters in the horizontal and vertical directions of the boundary value from the OLED lookup table to set parameters for determining the increase and decrease of the saturation.

The color correction method of the display device according to another embodiment of the present invention,

Converting input data of the three primary color spaces into corresponding color data of the corresponding color color space; Storing boundary values of saturation increase and decrease according to brightness components of the corresponding color data and material characteristics of the OLED; And calculating a parameter in the horizontal and vertical directions of the threshold to set a parameter for determining the increase and decrease of the saturation.

The display device according to an embodiment of the present invention has an advantage of improving image quality and reducing power consumption according to OLED material characteristics, brightness, and saturation of input data (R, G, B).

The present invention has the advantage of increasing the saturation in the case of low saturation image data and improving the image quality by reducing the saturation in the case of the high saturation image data and at the same time reducing power consumption.

The present invention can reduce power consumption by about 3.5 to 4.5% based on the total accumulated current of the display device, and increase the saturation for highly saturated image data to compensate for image quality in a general display device. Has the effect of preventing eye fatigue.

1 is a block diagram schematically illustrating a display device according to an exemplary embodiment of the present invention.
2 is a block diagram showing the configuration of the color correction unit of the present invention.
3 is a diagram illustrating a parameter adjusting unit for determining a parameter of the present invention.
4 and 5 are diagrams illustrating saturation correction according to information according to saturation and brightness of an image according to an exemplary embodiment of the present invention.
6 and 7 are diagrams for information on boundary values of saturation increase and saturation decrease stored in the OLED lookup table.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, embodiments of the present invention will be described in detail.

One embodiment of the present invention is intended to enable a person skilled in the art to fully understand the technical idea of the present invention. Therefore, the present invention is not limited to the embodiments described below, and other embodiments can be added on the basis of the technical idea of the present invention.

1 is a block diagram schematically illustrating a display device according to an exemplary embodiment of the present invention, FIG. 2 is a block diagram illustrating a configuration of a color correction unit of the present invention, and FIG. 3 is a parameter for determining a parameter of the present invention. It is a figure which shows a control part.

As shown in FIGS. 1 and 2, a display device according to an exemplary embodiment of the present invention may include an image display unit 110 displaying an image through OLED pixels, and a data line DL of the image display unit 110. A data driver 130 for driving, a gate driver 120 for driving the gate line GL of the image display unit 110, a timing controller for controlling the data driver 130 and the gate driver 120 ( 140, and a color correcting unit 150 for correcting and outputting the input data according to the saturation and brightness of the input image and the change of material properties of the OLED.

The timing controller 140 sorts the output data of the color corrector 150 and outputs the sorted output data to the data driver 130. In addition, the timing controller 140 drives the data driver 130 using a plurality of synchronization signals from the color corrector 150, that is, a dot clock, a data enable signal, a horizontal synchronization signal, and a vertical synchronization signal. A data control signal for controlling timing and a gate control signal for controlling driving timing of the gate driver 120 are generated and output.

The data driver 130 converts digital image data from the timing controller 140 into an analog data signal (current or voltage signal) using a gamma voltage in response to a data control signal from the timing controller 140. It is supplied to the data line DL of the display unit 110.

The gate driver 120 sequentially drives the gate line GL of the image display unit 110 in response to the gate control signal of the timing controller 140.

The image display unit 110 displays an image through a pixel matrix in which a plurality of pixels are arranged, and each pixel is an R / G / B sub connected to the data line DL, the gate line GL, and the power line PL. A pixel (not shown) is provided. Each subpixel includes at least switching and driving transistors SM and DM and one capacitor Cst to drive the OLED element. The switching and driving transistors SM and DM are formed of PMOS or NMOS transistors. The switching transistor SM is turned on by the gate turn-on voltage supplied to the gate line DL, and the data signal supplied to the data line DL is charged to the capacitor by the difference voltage between the driving voltage and the data signal. The driving transistor DM supplies a driving current according to the difference voltage charged to the capacitor to emit light of the OLED element, and the OLED displays a gray scale proportional to the driving current. The image display unit 110 may display a bright and clear image by displaying the correction data through the color corrector 150.

The color corrector 150 linearly converts input data R, G, and B of the three primary color spaces into corresponding color data I, RG, and YB of the corresponding color space. 151 and the brightness component (I) from the color space converter 151 and the material properties of the OLED, and the boundary values (RT_limit, LF_Limit, UP_limit, DN_limit) for setting the increase and decrease of saturation are stored. The parameter (k) is adjusted by using an OLED lookup table (OLED LUT) 161, boundary values (RT_limit, LF_Limit, UP_limit, DN_limit) from the OLED lookup table 161 and corresponding color data (RG / YB). The parameter adjusting unit 170 is included.

The color space converter 151 linearly converts input data R, G, and B of the three primary color spaces into corresponding color data RG / YG of the corresponding color space. The Opponent Color Space is a representation of the four colors of red, yellow, green, and blue representing the basic colors as a combination of red-green (RG) pairs and yellow-blue (YB) pairs. Because of the physiological features of the system, it can be used as an efficient color specification.

'I' of the Opponent Color Space means a brightness component, 'RG' represents a red-green relationship, and 'YB' represents a yellow-blue relationship.

The color space converter 151 may linearly convert the input data (R, G, B) into corresponding color data (I, RG, YB) by an operation using Equation 1 below.

Brightness components of 'I' among the corresponding color data I, RG and YB linearly transformed by Equation 1 are supplied to the OLED lookup table 161 and the inverse color space conversion unit 155, and include 'RG', The 'YB' component is supplied to the parameter adjusting unit 170 and the calculating unit 153, respectively.

The OLED lookup table 161 stores a brightness component defined as 'I' of the input data R, G, and B, and a threshold value (RT_limit, LF_Limit, UP_limit, DN_limit) set according to the material properties of the OLED. That is, the boundary values RT_limit, LF_Limit, UP_limit, and DN_limit are stored through experiments according to the relationship between the material properties of the OLED and the brightness components of the input data R, G, and B defined as 'I'.

Here, the threshold values RT_limit, LF_Limit, UP_limit, DN_limit may be changed according to the material efficiency and color characteristics of the OLED.

The boundary values RT_limit, LF_Limit, UP_limit, DN_limit of the OLED lookup table 161 serve as a reference for setting the increase and decrease of saturation.

1 to 3, the parameter adjusting unit 170 may include a first boundary value corresponding to a horizontal x-axis among the boundary values RT_limit, LF_Limit, UP_limit, and DN_limit of the OLED lookup table 161. An x-axis parameter calculator 171 for calculating an x-axis parameter kx for (RT_limit, LF_Limit) and a second boundary corresponding to the y-axis in the vertical direction among the boundary values RT_limit, LF_Limit, UP_limit, DN_limit The y-axis parameter calculator 173 for calculating the y-axis parameter kx for the values UP_limit and DN_limit, and the xy-axis calculated from the x-axis parameter calculator 171 and the y-axis parameter calculator 173. A collecting unit (MIN, 175) that takes a small value among the parameters and outputs the filter unit (LP), which compensates for the case where the collecting parameter (k_min) from the collecting unit (175) is discontinuous or noise is included. 177).

The x-axis parameter calculator 171 calculates an x-axis parameter kx for the first boundary values RT_limit and LF_Limit according to the increase and decrease of saturation for the RG axis. The x-axis is defined as the RG axis. can do.

The y-axis parameter calculator 173 calculates a y-axis parameter kx for the second boundary values UP_limit and DN_limit according to the increase and decrease of the saturation of the YB axis. The y-axis parameter is defined as the YB axis. can do.

The final parameter k output from the filter unit 177 is supplied to the corresponding color data RG and YB from the color space converter 151 and the calculation unit 153 for calculation.

The calculating unit 153 calculates the final parameter k from the filter unit 177 and the corresponding color data RG and YB, and converts the modulated corresponding color data RG 'and YB' into an inverse color space conversion unit ( 155).

The operation unit 153 performs an operation according to Equation 2 below.

The inverse color space conversion unit 155 uses the modulated corresponding color data RG 'and YB' and the brightness component 'I' to perform inverse transformation on the compensation data R ', G' and B ' ) Is supplied to the timing controller 140.

As described above, the display device according to the exemplary embodiment of the present invention has an advantage of improving image quality and reducing power consumption according to OLED material characteristics, brightness, and saturation of input data (R, G, B). .

4 and 5 are diagrams illustrating saturation correction according to information according to saturation and brightness of an image according to an exemplary embodiment of the present invention.

As shown in FIG. 4, in the case of video data with low chroma, the present invention can reduce the power consumption by increasing the chroma by adjusting the ratio of R, G, and B.

In particular, low saturation image data may increase the ratio of green G which is relatively efficient, and reduce the power consumption by decreasing the ratio of red R and blue B.

In other words, by increasing the ratio of high efficiency green (G) and reducing the ratio of low efficiency blue (B), the power consumption can be reduced by the efficiency difference of R, G, B, and the saturation is increased overall. The picture quality can be improved.

In this case, the brightness is the same as before and after the saturation change.

As shown in FIG. 5, the present invention can reduce saturation in the case of highly saturated image data, thereby reducing power consumption.

In detail, the image data has a large current reduction effect from the high gray lavel to the low gray lavel due to the gamma characteristic, and thus power consumption may be reduced by reducing the ratio of R, G, and B.

In this case, the brightness is the same as before and after the saturation change.

Accordingly, the present invention can increase the saturation in the case of the low saturation image data, reduce the power consumption by reducing the saturation in the case of the low saturation image data, and improve the image quality.

6 and 7 are diagrams for information on boundary values of saturation increase and saturation decrease stored in the OLED lookup table.

As shown in FIG. 6 and FIG. 7, the present invention provides a boundary value according to the material characteristics and intensity of the OLED in order to set the boundary values RT_limit, LF_Limit, UP_limit, DN_limit for increasing saturation and decreasing saturation. RT_limit, LF_Limit, UP_limit, DN_limit) are set.

Depending on the OLED's material properties, the thresholds (RT_limit, LF_Limit, UP_limit, DN_limit) are the criteria for increasing and decreasing saturation, and the increase in saturation is inside the threshold (RT_limit, LF_Limit, UP_limit, DN_limit). Reduction can be defined as the outside of the boundary value (RT_limit, LF_Limit, UP_limit, DN_limit).

As the boundary values RT_limit, LF_Limit, UP_limit, DN_limit, the inner area of the boundary values RT_limit, LF_Limit, UP_limit, DN_limit increases as the intensity of the input data increases.

The present invention increases the saturation in the region inside the boundary values (RT_limit, LF_Limit, UP_limit, DN_limit) according to the material properties and brightness of the OLED, and in the region outside the threshold values (RT_limit, LF_Limit, UP_limit, DN_limit). By reducing saturation, the image quality is improved and power consumption is also reduced.

That is, the present invention has the advantage of increasing the saturation in the case of the low saturation image data and improving the image quality by reducing the saturation in the case of the high saturation image data and at the same time reducing the power consumption.

The present invention can reduce power consumption by about 3.5 to 4.5% based on the total accumulated current of the display device, and increase the saturation for highly saturated image data to compensate for image quality in a general display device. Has the effect of preventing eye fatigue.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

150: color correction unit 151: color space conversion unit
153: operation unit 155: inverse color space conversion unit
161: OLED lookup table 170: Parameter adjustment unit
171: x-axis parameter calculator 173: y-axis parameter calculator
175: collecting section 177: filter section

Claims (14)

A color space converter for converting input data of three primary color spaces into corresponding color data of a corresponding color color space;
An OLED lookup table for storing boundary values of increasing and decreasing saturation according to brightness components of the corresponding color data and material characteristics of the OLED; And
And a parameter adjusting unit configured to calculate parameters in the horizontal and vertical directions of the boundary value from the OLED lookup table to set parameters for determining the increase and decrease of the saturation. The method according to claim 1,
The parameter adjusting unit,
A first parameter calculator configured to calculate a first axis parameter in a horizontal direction among the boundary values of the OLED lookup table;
A second parameter calculator configured to calculate a second axis parameter in a vertical direction among the boundary values of the OLED lookup table;
A collecting unit which collects a small value among the first and second parameters from the first and second parameter calculating units; And
And a filter unit for compensating for the case in which the collecting parameter from the collecting unit is discontinuous or includes noise. The method of claim 2,
And a calculation unit configured to calculate the final parameter from the filter unit and the corresponding color data of the red-green component and the yellow-blue component from the color space converter, and output the modulated corresponding color data. Compensator. The method of claim 3,
The calculator is configured to calculate the corresponding color data RG ′ and YB ′ modulated by the following operation using the final parameter K, the red-green component RG, and the yellow-blue component YB. Device color corrector.

The method of claim 3,
And an inverse color space converter configured to output compensation data using the modulated corresponding color data from the calculator and the brightness component from the color space converter. 6. The method of claim 5,
The inverse color space converter is configured to calculate compensation data R ', G', and B 'using the modulated data RG' and YB 'and the brightness component I through the following operation. Color Corrector.

6. The method of claim 5,
The final data is determined based on the boundary value capable of preventing deterioration of image quality according to the material property and the brightness component of the OLED, and when the saturation of the input data is low, the saturation is adjusted to high. A color compensator for a display device that adjusts the saturation when the input data is saturated. Converting input data of the three primary color spaces into corresponding color data of the corresponding color color space;
Storing boundary values of saturation increase and decrease according to brightness components of the corresponding color data and material characteristics of the OLED; And
Calculating a parameter in the horizontal and vertical directions of the boundary value and setting a parameter for determining the increase and decrease of the saturation. The method of claim 8,
Setting the parameter,
Calculating a first axis parameter in a horizontal direction among the boundary values;
Calculating a second axis parameter in a vertical direction among the boundary values;
Calculating a gathering parameter by collecting a small value among the first and second parameters; And
If the collection parameter is discontinuous or contains noise, compensating for the final parameter to generate a final parameter. 10. The method of claim 9,
And a calculation unit configured to calculate the corresponding parameter data of the final parameter, the red-green component, and the yellow-blue component, and output the modulated corresponding color data. The method of claim 10,
The calculator is configured to calculate the corresponding color data RG ′ and YB ′ modulated by the following operation using the final parameter K, the red-green component RG, and the yellow-blue component YB. Device color corrector.

The method of claim 10,
And an inverse color space converter for outputting compensation data using the modulated corresponding color data and the brightness component from the calculator. The method of claim 12,
The inverse color space converter is configured to calculate compensation data R ', G', and B 'using the modulated data RG' and YB 'and the brightness component I through the following operation. Color correction method.

The method of claim 12,
The final data is determined based on the boundary value capable of preventing deterioration of image quality according to the material property and the brightness component of the OLED, and when the saturation of the input data is low, the saturation is adjusted to high. A method of correcting a color of a display device, in which the saturation is adjusted low when the input data is highly saturated.

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