KR102582376B1 - Organic light emitting display device and image processing method thereof - Google Patents

Abstract

An organic light emitting display device and its image processing method are provided. The organic light emitting display device according to the present invention includes a display panel including a plurality of pixels consisting of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel, and an RGB data signal converted into an R'G'B'W' data signal. A first data conversion unit that converts a partial gray level value of the W' data signal among the R'G'B'W' data signals to the gray level of the R'G'B' data signal among the R'G'B'W' signals. It includes an image processor including a second data converter that generates a final RGBW data signal by converting it into a value, and a timing controller that outputs the final RGBW data signal input from the image processor to the display panel.

Description

Organic light emitting display device and image processing method thereof {ORGANIC LIGHT EMITTING DISPLAY DEVICE AND IMAGE PROCESSING METHOD THEREOF}

The present invention relates to an organic light emitting display device and an image processing method thereof.

In the recent information age, display devices are becoming popular at a rapid pace. Due to the characteristics of these display devices, such as light weight, thinness, and low power consumption, their application range is gradually expanding to include not only TVs, monitors, and laptops, but also mobile phones, PDAs, and smartphones.

These display devices include Liquid Crystal Display (LCD), Plasma Display Panel Device (PDP), Field Emission Display Device (FED), and Organic Light Emitting Display (Organic Light Emitting Display). OLED), etc.

Among these, the organic light emitting display device is a device that displays an image by self-emitting light when gate signals, data signals, and power are supplied to subpixels arranged in a matrix. It not only has a wide viewing angle and excellent contrast, but also has excellent contrast. Because it has the advantage of fast response speed, it is attracting attention as a next-generation device.

Recently, an RGBW type organic light emitting display device including red, green, blue, and white has been proposed to increase light efficiency while preventing deterioration in luminance and color of pure colors.

The RGBW type organic light emitting display device extracts the optimal W data signal based on the three colors of RGB data signals input from the outside, and produces an R'G'B' data signal with the same luminance and same color coordinates as the optimal W data signal. By extracting the RGB data signals and subtracting the R'G'B' data signals from the RGB data signals, the optimal W data signal is added to generate an RGBW data signal and applied to the red, green, blue, and white subpixels to display the image. do.

When an RGB data signal is converted to an RGBW data signal in this way, the gray level value for one of the RGB data signals is treated as 0 by subtracting the R'G'B' data signal from the RGB data signals, and thus, the general There is an advantage in minimizing the power consumption of an RGBW-type organic light emitting display device.

Meanwhile, a more detailed look at the pixel structure of a general organic light emitting display device, including an RGBW type organic light emitting display device, is shown in Figure 1 below.

1 is an equivalent circuit diagram showing a pixel of a typical organic light emitting display device.

Referring to FIG. 1, a pixel of a typical organic light emitting display device is a switching transistor that applies a data signal input through a data line DL to the first node N1 in response to a gate signal applied to the gate line GL. (STFT), a driving transistor (DTFT) that receives the data signal and applies drain-source current to the organic light emitting diode (OLED) according to the voltage applied to the first node (N1), and the voltage applied to the driving transistor (DTFT) It includes a capacitor (C) that maintains for one frame.

This driving transistor (DTFT) controls the amount of current flowing through the organic light-emitting diode (OLED) to display grayscale images. Unlike the switching transistor (STFT), the driving transistor (DTFT) is subject to continuous driving voltage, so it is prone to deterioration, which can reduce the reliability of the organic light emitting display device.

To solve this problem of the driving transistor (TFT), a structure that compensates for the threshold voltage characteristics of the driving transistor (DTFT) inside or outside the panel has been proposed.

Among them, the external compensation method is equipped with a sensing means for sensing the threshold voltage of the driving transistor (DTFT) outside the panel and a reference wiring connected thereto to sense the threshold voltage of the driving transistor (DTFT) and compensate the data voltage according to the results. This is the way to do it. In addition, the external compensation method secures a margin of compensation voltage in advance by considering the case where the threshold voltage of the driving transistor (DTFT) shifts negatively, and for this purpose, an offset is set in the source node of the driving transistor (DTFT). ) has a structure that takes.

Meanwhile, in recent external compensation methods, in order to solve the problem of flicker occurring in some parts of the screen due to the deviation of the overall threshold voltage, a gate voltage of 0V is applied to the subpixel with 0 gray level, so that the driving transistor (DTFT) is It is controlled so that it turns off reliably.

When such an external compensation method of the driving transistor (DTFT) is adopted in the above-described RGBW-type organic light-emitting display device, the RGBW-type organic light-emitting display device has Among the pixels, there is a subpixel with 0 gray level, and the driving transistor (DTFT) configured in that subpixel has a gate voltage of 0V when considering external compensation, so the gate-source voltage of the driving transistor (DTFT) is negative. bias).

In this way, the RGBW type organic light emitting display device has a problem in that the reliability of the organic light emitting display device is reduced because the driving transistor configured in the subpixel with 0 gray level is prone to deterioration when a negative voltage is applied.

In addition, the RGBW type organic light emitting display device includes a red subpixel, a green subpixel, a blue subpixel, and a white subpixel, and color filters are disposed in the red subpixel, green subpixel, and blue subpixel except for the white subpixel. . As such, since a color filter is not disposed in the white subpixel, the transmittance of the white subpixel is relatively better than that of the red, green, and blue subpixels. Accordingly, the driving transistor disposed in the white subpixel may be driven with a lower driving voltage than the driving transistor disposed in each of the red, green, and blue subpixels.

However, a general driving transistor has relatively poor characteristics when driven by a low driving voltage compared to when driven by a high driving voltage. Accordingly, the driving transistor disposed in the RGBW-type organic light-emitting display device has a characteristic deviation between subpixels, which causes the problem that the uniformity of the display quality of the RGBW-type organic light-emitting display device deteriorates. there is.

Accordingly, the problem to be solved by the present invention is to minimize power consumption in an RGBW type organic light emitting display device and prevent deterioration of the driving transistor configured in the subpixel to improve the reliability of the organic light emitting display device and its It provides an image processing method.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

In order to solve the problems described above, an organic light emitting display device according to an embodiment of the present invention includes a display panel including a plurality of pixels consisting of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel, and RGB data. A first data converter for converting a signal into an R'G'B'W' data signal and converting a partial grayscale value of the W' data signal among the R'G'B'W' data signals into the R'G'B'W' data signal. An image processor including a second data converter for generating a final RGBW data signal by replacing the grayscale value of the R'G'B' data signal among the signals, and outputting the final RGBW data signal input from the image processor to the display panel. Includes a timing controller that

An image processing method of an organic light emitting display device according to another embodiment of the present invention is an image processing method of an organic light emitting display device including a plurality of pixels consisting of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel. , converting the RGB data signal into an R'G'B'W' data signal, converting some gray scale values of the W' data signal among the R'G'B'W' data signals into the R'G'B'W' data It includes the step of replacing the signal with the gray level value of the R'G'B' data signal and outputting the final RGBW data signal.

Specific details of other embodiments are included in the detailed description and drawings.

The organic light emitting display device according to the present invention converts the RGB data signal into an R'G'B'W' data signal and converts the data signal with a grayscale value of 0 among the R'G'B'W' data signals to a value greater than 0. By substituting to have , deterioration of the driving transistor can be prevented.

The organic light emitting display device according to the present invention converts the RGB data signal into the R'G'B'W' data signal and then replaces the R'G'B'W' data signal according to the grayscale value of the W' data signal. By adjusting the substitution ratio that can replace some grayscale values of the W' data signal with grayscale values of the R'G'B' data signal, power consumption can be minimized and uniformity of RGB subpixels can be improved.

The effects according to the present invention are not limited to the contents exemplified above, and further various effects are included in the present specification.

1 is an equivalent circuit diagram showing a pixel of a typical organic light emitting display device.
Figure 2 is a block diagram schematically showing the configuration of an organic light emitting display device according to an embodiment of the present invention.
FIG. 3 is a block diagram schematically showing the configuration of the image processing unit of FIG. 2.
FIG. 4 is a block diagram schematically showing the configuration of the first data conversion unit of FIG. 3.
FIG. 5 is a diagram for explaining a data conversion method in the first data conversion unit of FIG. 3.
FIG. 6 is a block diagram schematically showing the configuration of the second data conversion unit of FIG. 3.
FIG. 7 is a diagram for explaining the data replacement rate according to gray level in the second data converter of FIG. 3.
FIG. 8 is a diagram for explaining a data conversion method in the second data conversion unit of FIG. 3.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are illustrative, and the present invention is not limited to the matters shown. Like reference numerals refer to like elements throughout the specification. Additionally, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description.

In the case of a description of a positional relationship, for example, if the positional relationship of two parts is described as 'on top', 'on the top', 'on the bottom', 'next to', etc., 'immediately' Alternatively, there may be one or more other parts placed between the two parts, unless 'directly' is used.

When an element or layer is referred to as “on” another element or layer, it includes instances where the other layer or other element is directly on top of or interposed between the other elements.

Although first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are merely used to distinguish one component from another. Accordingly, the first component mentioned below may also be the second component within the technical spirit of the present invention.

Like reference numerals refer to like elements throughout the specification.

The size and thickness of each component shown in the drawings are shown for convenience of explanation, and the present invention is not necessarily limited to the size and thickness of the components shown.

Each feature of the various embodiments of the present invention can be partially or fully combined or combined with each other, and as can be fully understood by those skilled in the art, various technical interconnections and operations are possible, and each embodiment may be implemented independently of each other. It may be possible to conduct them together due to a related relationship.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings.

Figure 2 is a block diagram schematically showing the configuration of an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 2, the organic light emitting display device 100 according to an embodiment of the present invention includes a display panel 210, a gate driver 220, a data driver 230, an image processor 240, and a timing controller 250. ) includes. In FIG. 2, the image processing unit 240 and the timing controller 250 are described as separate components, but the image processing unit 240 may be included in the timing controller 250, and the image processing unit 240 and the timing controller may be included in the timing controller 250. (250) may be formed integrally.

In the display panel 210, m data lines (DL1, DL2, ... DLm) in the first direction and n gate lines (GL1, GL2, ... GLn) in the second direction that intersect the first direction are arranged. Additionally, in the display panel 210, a plurality of pixels (PX) are defined by m data lines (DL1, DL2, ... DLm) and n gate lines (GL1, GL2, ... GLn).

Each pixel PX includes red, green, blue, and white subpixels, and each subpixel includes a switching transistor, a driving transistor, a capacitor, and an organic light emitting diode. The switching transistor operates in response to the gate signal supplied through the gate lines (GL1, GL2, ... GLn) so that the data signal supplied through the data lines (DL1, DL2, ... DLm) is supplied and stored in the capacitor as a data voltage. do. The driving transistor operates to cause the organic light emitting diode to emit light by allowing a driving current to flow to the organic light emitting diode according to the data voltage stored in the capacitor.

Meanwhile, the red, green, blue, and white subpixels may be configured with a structure in which more transistors and capacitors are added, such as 2T1C, 3T1C, 4T2C, 5T2C, etc., including a switching transistor, a driving transistor, a capacitor, and an organic light emitting diode.

The display panel 210 configured in this way may be formed in a top-emission method, a bottom-emission method, or a dual-emission method depending on the structure of the subpixel.

The display panel 210 may further have o reference lines (RL1, RL2, ... RLo) arranged in the first direction to which a reference voltage for sensing the amount of change in the threshold voltage of the driving transistor disposed in the subpixel is applied. The reference lines RL1, RL2, ... RLo are connected to the data driver 230 to apply a reference voltage to the pixel PX. Meanwhile, the reference line SL may not be arranged for each subpixel, but one reference line SL may be arranged for each pixel PX to secure the opening.

The gate driver 220 sequentially applies a gate-on voltage to transistors of subpixels of the display panel 210 in response to the gate control signal GCS input from the timing controller 250. The gate driver 220 may include a shift register that sequentially generates gate-on voltage.

The data driver 230 samples and latches the image data signal among the data signals (Data) supplied from the timing controller 250 in response to the data control signal (DCS) from the timing controller 250 to convert it into a data signal of a parallel data system. Convert. The data driver 230 receives the RGBW data signal from the timing controller 250, converts the input RGBW data signal into an analog data signal, and transmits it to the pixel (PX) through m data lines (DL1, DL2, ... DLm). Authorize. The data driver 230 senses the pre-deterioration threshold voltage and the post-deterioration threshold voltage of the driving transistor provided in each subpixel using an external compensation method immediately after turning on/off the power of the organic light emitting display device or at other times designated by the designer. The sensed sensing data (se_data) is transmitted to the timing controller 250. In addition, the threshold voltage of the driving transistor provided in the subpixel of the display panel 210 can be sensed using a voltage follower method using a switching transistor. Meanwhile, in one embodiment of the present invention, it has been described that the deterioration of the driving transistor of the subpixel is sensed by the data driver 230, but this is not limited to this, and the deterioration sensing unit can be configured in a separate configuration from the data driver 230. It may be possible.

When three-color RGB data signals are input from the outside, the image processing unit 240 first converts the RGB data signals into four-color R'G'B'W' data signals and converts them into R'G'B'W' data signals. The R'G'B'W' data signal is secondarily converted to have a non-zero gray level value by replacing the data signal with a gray level value of 0, thereby generating a final RGBW data signal and outputting it to the timing controller 250. First, the image processing unit 240 converts the RGB data signal into an R'G'B'W' data signal, and converts the RGB data signal into R' based on actual or calculated values having luminance and color coordinates corresponding to the W' data signal. Convert the RGB data signal to R'G'B'W' data signal by subtracting the ''G'''B''' data signal and adding the 'W' data signal. At this time, the image processing unit 240 may process the image so that one of the converted R'G'B'W' data signals has a grayscale value of 0 in order to minimize power consumption. However, a driving transistor configured in a subpixel representing a data signal with a gray level value of 0 has a problem in that a negative bias voltage is applied to the driving transistor because the data signal has a gray level value of 0, thereby deteriorating the characteristics of the driving transistor. Accordingly, the image processing unit 240 of the organic light emitting display device according to the present invention replaces some gray scale values of the W' data signal among the R'G'B'W' data signals with the gray scale values of the R'G'B' data signal. Thus, a data signal with a grayscale value of 0 in the final RGBW data signal can be image processed. The detailed configuration of the image processing unit 240 will be examined with reference to FIG. 3 below.

The timing controller 250 receives the final RGBW data signal from the image processor 240 and supplies it to the data driver 230. In addition, the timing controller 250 uses timing signals input from the outside, such as the main clock (MCLK), data enable signal (DE), vertical synchronization signal (Vsync), and horizontal synchronization signal (Hsync), to operate the gate driver 220. and generate a gate control signal (GCS) and a data control signal (DCS) that control the operation timing of the data driver 230. In addition, the timing controller 250 receives sensing data (se_data) that senses the deterioration of the driving transistor provided in the subpixel from the data driver 230, and determines the degree of deterioration of the driving transistor based on the sensing data (se_data). Compensation data is generated and transmitted to the data driver 230. Meanwhile, in one embodiment of the present invention, it has been described that the timing controller 250 generates compensation data to compensate for the deterioration of the driving transistor disposed in the subpixel and applies it to the data driver 230, but the present invention is not limited to this. A compensation data generator may be provided in a separate configuration from the timing controller 250.

FIG. 3 is a block diagram schematically showing the configuration of the image processing unit of FIG. 2.

Referring to FIG. 3, the image processing unit 240 of the organic light emitting display device according to an embodiment of the present invention includes a first data conversion unit 241, a frame memory unit 242, and a second data conversion unit 243. It can be included.

The first data converter 241 converts the RGB data signal into an R'G'B'W' data signal. The first data converter 241 extracts the W' data signal from the RGB data signal to optimize power consumption without changing the luminance and color coordinates, and based on actual or calculated values having luminance and color coordinates corresponding to the W' data signal. Subtract the R''G''B'' data signal and add the W' data signal. A more detailed description of the first data conversion unit 241 will be described with reference to FIGS. 4 and 5 below.

The frame memory unit 242 may store frame data information when the first data conversion unit 241 converts the RGB data signal into an R'G'B'W' data signal. The frame memory unit 242 can convert the RGB data signal into the R'G'B'W' data signal and then store information about the data signal with a grayscale value of 0 among the R'G'B'W' data signals. . For example, assuming that the frame memory unit 242 has 32 bits, frame information for three data signals with non-zero grayscale values among the R'G'B'W' data signals can be stored in 30 bits, In 2 bits, information about the data signal with a gray level value of 0 among the R'G'B'W' data signals can be stored. For example, in 2 bits of the frame memory unit 242, if the value of 2 bits is 00, the R' data signal is determined to have a gray level value of 0, and if the value of 2 bits is 01, the G' data signal is determined to have a gray level value of 0. If the 2-bit value is 10, the B' data signal is judged to have a gray-scale value of 0, and if the 2-bit value is 11, the W' data signal is judged to have a gray-scale value of 0. can be saved. Accordingly, the organic light emitting display device according to an embodiment of the present invention stores information and grayscale values of three data signals with non-zero grayscale values among the R'G'B'W' data signals in the frame memory unit 242. By storing information about this 0 data signal, a separate memory configuration is not required when replacing a data signal with a gray level of 0 among the R'G'B'W' data signals to have a value greater than 0. In other words, a typical RGBW type organic light emitting display device had to have a frame memory unit of 40 bits because each RGBW data signal has a gray level value when converting an RGB data signal into an RGBW data signal. However, when converting an RGB data signal into an R'G'B'W' data signal, the RGBW type organic light emitting display device according to an embodiment of the present invention converts the signal to one of the R'G'B'W' data signals. 30 bits to store information about the three data signals excluding the data signal with a gray level of 0 by setting the gray level to 0, and a data signal with a gray level of 0 to prevent deterioration of the driving transistor of the external compensation method. Since only 2 bits, that is, a total of 32 bits, are needed to store information about, the size of the frame memory unit can be reduced.

The second data conversion unit 243 reads a 2-bit value from the frame memory unit 242 and, when one of the R'G'B' data signals is 0, W among the R'G'B'W' data signals 'Some grayscale values of the data signal are replaced with grayscale values of the R'G'B' data signal among the R'G'B'W' signals to generate a final RGBW data signal. A more detailed description of the second data conversion unit 243 will be described with reference to FIGS. 6 to 8 below.

FIG. 4 is a block diagram schematically showing the configuration of the first data conversion unit of FIG. 3. FIG. 5 is a diagram for explaining a data conversion method in the first data conversion unit of FIG. 3.

Referring to FIG. 4, the first data conversion unit 241 may include a first conversion unit 2411, a minimum value selection unit 2412, a second conversion unit 2413, and a first data output unit 2414. there is.

The first converter 2411 converts each RGB data signal into a W1 data signal to a W3 data signal. That is, the first converter 2411 can convert the R data signal into a W1 data signal, convert the G data signal into a W2 data signal, and convert the B data signal into a W3 data signal. For example, the first converter 2411 may convert the grayscale value of the RGB data signal into a conversion curve and convert it into a W data signal for each RGB data signal.

The minimum value selection unit 2412 selects the W data signal with the minimum value among the W1 data signal to the W3 data signal as the W' data signal. Referring to FIG. 5, as shown in (a), if the R data signal of the RGB data signal has a gray level value of 170, the G data signal has a gray level value of 220, and the B data signal has a gray level value of 190, the corresponding After converting the W1 data signal to the W3 data signal in the first converter 2411, the W1 data signal is converted into a W' data signal because the gray level value of the R data signal has a lower gray level value than the G data signal and the B data signal. You can choose. At this time, as shown in (b) of FIG. 5, it is assumed that the gray level value of the W1 data signal obtained by converting the R data signal to W is 160, which is the minimum value compared to the W2 data signal and the W3 data signal. Accordingly, the minimum value selection unit 2412 selects the W1 data signal as the W' data signal and outputs it.

The second converter 2413 may convert the RGB data signal into an R'''G'''B''' data signal to correspond to the W' data signal output from the minimum value selection unit 2412. For example, since the grayscale value of the W' data signal is 160, the second converter 2413 converts a separately preset conversion curve or the W' data signal into a corresponding R'''G'''B''' data signal. The RGB data signal can be converted based on actual measurements or calculated values to be converted to . Referring to FIG. 5, as shown in (c), the gray scale value of the W' data signal is 160, and the gray scale values of the corresponding R'''G'''B''' data signals are 170, 150, and 100, respectively. It is assumed to have . Accordingly, the grayscale values of the R'''G'''B''' data signal, which has luminance and color coordinates corresponding to the grayscale value of 160 of the W' data signal, may have 170, 150, and 100.

The first data output unit 2414 subtracts the R'''G'''B''' data signal from the RGB data signal and adds the W' data signal to output the R'G'B'W' data signal. . That is, the first data may refer to the R'G'B'W' data signal. Referring to FIG. 5, the gray scale value of the RGB data signals is R 170 G 220 B 190 as shown in (a), and the gray scale value of the R'''G'''B''' data signal is R 170 as shown in (b). After subtracting G 150 B 100 and adding W 160, which is the gray scale value of the W' data signal, as shown in (c), first data has a gray scale value of R 0 G 70 B 90 W 160, as shown in (d). The signal R'G'B'W' data signal is output.

In this way, the first data converter 241 converts the RGB data signal into a W data signal based on actual measurements or calculated values and outputs it, so the color coordinates of the converted R'G'B'W' data signals do not change. In addition, the first data conversion unit 241 subtracts the RGB data signal from the R'''G'''B''' data signal based on actual measurements or calculated values, so that among the converted R'G'B' data signals, The gray level value of one data signal is treated as 0.

However, since the gray level value of one of the converted R'G'B'W' data signals has 0, power consumption can be minimized, but it may have a negative effect on the driving transistor characteristics of the subpixel with a gray level value of 0. You can. This is because the gate-source voltage of the driving transistor may have a negative bias value, and as a result, the driving transistor may easily deteriorate.

Accordingly, the organic light emitting display device according to an embodiment of the present invention uses the R'G'B'W' data signal so that there is no data signal with a gray level of 0 so as to minimize power consumption and deterioration of the driving transistor. Let's take a look at the second data converter that converts and outputs the final RGBW data signal.

FIG. 6 is a block diagram schematically showing the configuration of the second data conversion unit of FIG. 3. FIG. 7 is a diagram for explaining the data replacement rate according to gray level in the second data converter of FIG. 3.

Referring to FIG. 6, the second data conversion unit 243 of the organic light emitting display device according to an embodiment of the present invention receives information of the R'G'B'W' data signal from the frame memory unit 242 and If the W' data signal has a gray scale value other than 0 and one of the R'G'B' data signals has a gray scale value of 0, R'G'B' converted in the first data converter 241 A final RGBW data signal is generated by replacing some grayscale values of the W' data signal among the W' data signals with grayscale values of the R'G'B' data signal among the R'G'B'W' data signals. At this time, the final RGBW data signal may be second data. This second data conversion unit 243 may include a reference value setting unit 2431, a data replacement unit 2432, and a second data output unit 2433.

The reference value setting unit 2431 sets a reference value for determining whether the gray level value of the W' data signal is high gray level or low gray level. These reference values can be set to vary depending on the characteristics of the display panel, the number of bits, etc. Referring to the graph of FIG. 7, when the reference value (ref) is determined as shown in FIG. 7 in consideration of panel characteristics and bits, the reference value setting unit 2431 selects an area where the gray level value is higher than the reference value (ref). can be set as a high grayscale area (HGA), and an area with a grayscale value lower than the reference value (ref) can be set as a low grayscale area (LGA) with a low grayscale value. At this time, the grayscale value and replacement ratio of the W' data signal in the low grayscale area (LGA) may have a linear relationship. That is, if the gray level value of the W' data signal corresponds to the low gray level area (LGA), the lower the gray level value of the W' data signal, the higher the rate of replacement with the gray level value of the R'G'B' data signal. As such, subpixels corresponding to the low grayscale area (LGA) have low grayscale values and therefore have low driving voltages. Accordingly, a difference in driving characteristics may occur between the driving transistor disposed in the white subpixel corresponding to the low gray area (LGA) and the driving transistor disposed in each of the red, green, and blue subpixels, an embodiment of the present invention. In the low grayscale area (LGA), the ratio of grayscale values that are replaced from W' data signals to R'G'B' data signals can be increased, thereby reducing the luminance deviation between white subpixels and red, green, and blue subpixels. . Accordingly, the uniformity of display quality of the organic light emitting display device according to an embodiment of the present invention can be improved.

Additionally, the reference value setting unit 2431 can set the maximum substitution ratio (a _max ). The maximum substitution ratio (a _max ) can be set considering the gray level value and power consumption of the RGBW data signal. More specifically, the maximum substitution ratio (a _max ) may be selected as a value that can minimize power consumption within a range in which a data signal with a grayscale value of 0 is not generated among the RGBW data signals that are final output data.

The data replacement unit 2432 may replace a portion of the grayscale value of the W' data signal among the R'G'B'W' data signals with the grayscale value of the R'G'B' data signal. More specifically, the data replacement unit 2432 replaces a portion of the grayscale value of the W' data signal with the R'G'B' data signal in response to the replacement ratio of the W' data set based on the grayscale value of the W' data signal. It can be replaced with grayscale value. For example, if the grayscale value of the W' data signal is a high grayscale value that is higher than the reference value (ref), the data replacement unit 2432 replaces the W' data among R'G'B'W' according to the maximum replacement ratio (a _max ). Part of the gray level value of the signal is replaced with the gray level value of the R'G'B' data signal, and if the gray level value of the W' data signal is a low gray level value less than the reference value (ref), substitution is proportional to the gray level value of the W' data signal. Depending on the ratio, part of the gray level value of the W' data signal can be replaced with the gray level value of the R'G'B' data signal.

The second data output unit 2433 outputs a final RGBW data signal obtained by converting the R'G'B'W' data signal so that there is no data signal with a gray level value of 0 according to the reference value (ref).

The process of converting the R'G'B'W' data signal into the final RGBW data signal by the second data conversion unit 243 will be examined in more detail with reference to FIG. 8.

FIG. 8 is a diagram for explaining a data conversion method in the second data conversion unit of FIG. 3.

Referring to FIG. 8, the RGB data signal is converted into an R'G'B'W' data signal to have a grayscale value of R 0 G 70 B 90 W 160 in the first data converter 241, as shown in (a). Convert.

At this time, the gray level value of the converted W' data signal is 160. Referring to FIG. 7, it can be seen that if the gray level value of the W' data signal is 160, it corresponds to the high gray level area (HGA).

In this way, if the grayscale value of the W' data signal is higher than the reference value (ref), part of the grayscale value of the W' data signal can be replaced according to the maximum substitution ratio (a _max ). At this time, the value to be replaced among the grayscale values of the W' data signal can be calculated by multiplying the grayscale value (W'in) of the W' data signal by the maximum substitution ratio (a _max ). Referring to FIG. 7, assuming that the maximum substitution ratio (a _max ) is set to 94%, the grayscale value (Win) of the W' data signal was 160, so 160X0.94=150.4 is calculated. Here, if the decimal places are discarded, the result value is 150. Here, the result value may be the grayscale value of the final W data that can minimize power consumption. Accordingly, the substitution value that can be substituted for the grayscale value of the W' data signal may be 10.

Accordingly, the data replacement unit 2432 of the second data conversion unit 243 subtracts the replacement value 10 from the grayscale value 160 of the W' data signal, as shown in (b).

In this way, the second data converter 243 adds the gray level value of the R''G''B'' data signal, as shown in (c), to correspond to 10 subtracted from the gray level value of the W' data signal. , As shown in (d), a final RGBW data signal with grayscale values of R 10 G 80 B 100 W 150 is output. More specifically, in step (c), the average gray level value of the R''G''B'' data signal may be equal to a value subtracted from the gray level value of the W' data signal. In FIG. 8, each grayscale value of the R''G''B'' data signal is added at the same ratio to correspond to the subtraction value of the grayscale value of the W' data signal, but the present invention is not limited to this, and the R'' data, G '' Data and B'' data can be added at different rates.

As such, the organic light emitting display device and its image processing method according to an embodiment of the present invention convert the RGB data signal into the R'G'B'W' data signal and then convert the R'G'B'W' data signal into the R'G'B'W' data signal. Deterioration of the driving transistor can be prevented by replacing a data signal with a gray level value of 0 to have a value greater than 0.

The organic light emitting display device according to the present invention converts the RGB data signal into the R'G'B'W' data signal and then replaces the R'G'B'W' data signal according to the grayscale value of the W' data signal. By adjusting the substitution ratio that can replace some grayscale values of the W' data signal with grayscale values of the R'G'B' data signal, power consumption can be minimized and uniformity of RGB subpixels can be improved.

An organic light emitting display device according to an embodiment of the present invention includes a display panel including a plurality of pixels consisting of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel, and an RGB data signal R'G'B'W ' A first data converter that converts a partial gray scale value of the W' data signal among the R'G'B'W' data signals into a data signal as R'G'B' among the R'G'B'W' signals. It includes an image processing unit including a second data converter that generates a final RGBW data signal by replacing the gray level value of the data signal, and a timing controller that outputs the final RGBW data signal input from the image processing unit to the display panel.

The image processing unit further includes a frame memory unit storing information about the R'G'B'W' data signal, and a second data converting unit stores the R'G'B'W' data signal received from the frame memory unit. Among the information, if the W' data signal has a gray level value other than 0 and one of the R'G'B' data signals has a gray level value of 0, the gray level value of the W' data signal is adjusted to determine the R'G' Among the B' data signals, a data signal with a grayscale value of 0 can be converted to have a value greater than 0.

The second data converter replaces the gray level value of the W' data signal with the gray level value of the R'G'B' data signal in response to the replacement ratio of the W' data signal set based on the gray level value of the W' data signal. can do.

If the gray level value of the W' data signal is greater than or equal to the reference value, the second data converter replaces a portion of the gray level value of the W' data signal with the gray level value of the R'G'B' data signal according to the maximum substitution ratio, and W' If the gray level value of the data signal is less than the reference value, a portion of the gray level value of the W' data signal is converted to the gray level value of the R'G'B' data signal according to a replacement ratio proportional to the gray level value of the W' data signal. It can be replaced.

The maximum replacement ratio can be set considering the gray level value and power consumption of the RGBW data signal.

When the grayscale value of the W' data signal is less than the reference value, the grayscale value of the W' data signal and the replacement ratio may have a linear relationship.

A first data converter extracts the W' data signal based on the RGB data signal, and R' has luminance and color coordinates corresponding to the W' data signal based on the data signal with the minimum gray scale value among the RGB data signals. Extract the 'G''B'' data signal, subtract the gray level value of the R''G''B'' data signal from the gray level value of the RGB data signal, and add the W' data signal to the R A 'G'B'W' data signal can be generated.

The gray level value of one data signal among the R'G'B' data may be 0.

Each subpixel constituting a plurality of pixels includes a switching transistor, a driving transistor, a capacitor, and an organic light emitting diode.

The timing controller may generate compensation data for the driving transistor according to the sensed threshold voltage of the driving transistor.

An image processing method of an organic light emitting display device according to an embodiment of the present invention includes an image processing method of an organic light emitting display device including a plurality of pixels consisting of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel. , converting the RGB data signal into an R'G'B'W' data signal, converting some gray scale values of the W' data signal among the R'G'B'W' data signals into the R'G'B'W' data It includes replacing the R'G'B' data signal with the gray level value of the signal and outputting the final RGBW data signal.

The step of replacing some of the gray scale values of the W' data signal among the R'G'B'W' data signals with the gray scale values of the R'G'B' data signal among the R'G'B'W' data signals includes the W' The gray level value of the W' data signal may be replaced with the gray level value of the R'G'B' data signal in response to a replacement ratio of the W' data signal set based on the gray level value of the data signal.

If the gray level value of the W' data signal is greater than the reference value, a portion of the gray level value of the W' data signal is replaced with the gray level value of the R'G'B' data signal according to the maximum substitution ratio, and the gray level value of the W' data signal is replaced with the gray level value of the R'G'B' data signal. If it is less than the reference value, a portion of the gray level value of the W' data signal may be replaced with the gray level value of the R'G'B' data signal according to a replacement ratio proportional to the gray level value of the W' data signal.

Converting the RGB data signal into the R'G'B'W' data signal includes extracting the W' data signal based on the RGB data signal, and extracting the W' data signal based on the data signal with the minimum gray level value among the RGB data signals. Extracting an R''G''B'' data signal having luminance and color coordinates corresponding to the W' data signal and a gray level of the R''G''B'' data signal from the gray level value of the RGB data signal. Subtracting the value and adding the W' data signal may include generating the R'G'B'W' data signal.

Although embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made without departing from the technical spirit of the present invention. .

Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be construed as being included in the scope of rights of the present invention.

210: display panel
220: Gate driver
230: data driving unit
240: Image processing unit
250: Timing controller
241: First data conversion unit
242: Frame memory unit
243: Second data conversion unit
2411: first conversion unit
2412: Minimum value selection unit
2413: second conversion unit
2414: first data output unit
2431: Reference value setting unit
2432: Data replacement unit
2433: second data output unit

Claims (14)

A display panel including a plurality of pixels including a red subpixel, a green subpixel, a blue subpixel, and a white subpixel;
From a first data conversion unit that converts an RGB data signal into an R'G'B'W' data signal, a frame memory unit that stores information about the R'G'B'W' data signal, and the frame memory unit. If the W' data signal among the received information of the R'G'B'W' data signal has a gray level value other than 0 and one of the R'G'B' data signals has a gray level value of 0, Some gray scale values of the W' data signal among the R'G'B'W' data signals are replaced with gray scale values of the R'G'B' data signal among the R'G'B'W' signals, so that the gray scale value is 0. An image processing unit including a second data conversion unit that generates a final RGBW data signal so that there is no data signal; and
An organic light emitting display device comprising a timing controller that outputs the final RGBW data signal input from the image processor to the display panel. According to paragraph 1,
The second data converter determines that the W' data signal among the information of the R'G'B'W' data signal received from the frame memory unit has a grayscale value other than 0 and is among the R'G'B' data signals. Organic light emitting, where the gray level value of the W' data signal is adjusted when one of the R'G'B' data signals has a gray level value of 0 so that the data signal with a gray level value of 0 among the R'G'B' data signals has a value greater than 0. Display device. According to paragraph 2,
The second data converter converts the grayscale value of the W' data signal to the grayscale value of the R'G'B' data signal in response to a replacement ratio of the W' data signal set based on the grayscale value of the W' data signal. Replaced by an organic light emitting display device. According to paragraph 3,
The second data conversion unit,
When the gray level value of the W' data signal is greater than a reference value, a portion of the gray level value of the W' data signal is replaced with the gray level value of the R'G'B' data signal according to a maximum substitution ratio,
If the gray level value of the W' data signal is less than the reference value, a portion of the gray level value of the W' data signal is converted into the R'G'B' data signal according to a replacement ratio proportional to the gray level value of the W' data signal. An organic light emitting display device that replaces grayscale values. According to paragraph 4,
The organic light emitting display device wherein the maximum replacement ratio is set in consideration of the gray level value and power consumption of the RGBW data signal. According to paragraph 4,
When the grayscale value of the W' data signal is less than the reference value, the grayscale value of the W' data signal and the replacement ratio have a linear relationship. According to paragraph 1,
The first data conversion unit,
The W' data signal is extracted based on the RGB data signal, and R''G'' has luminance and color coordinates corresponding to the W' data signal based on the data signal with the minimum gray scale value among the RGB data signals. Extract the B'' data signal, subtract the gray level value of the R''G''B'' data signal from the gray level value of the RGB data signal, and add the W' data signal to the R'G'B An organic light emitting display device that generates a 'W' data signal. In clause 7,
An organic light emitting display device, wherein the gray level value of one of the R'G'B' data signals is 0. According to paragraph 1,
Each subpixel constituting the plurality of pixels includes a switching transistor, a driving transistor, a capacitor, and an organic light emitting diode. According to clause 9,
The timing controller generates compensation data for the driving transistor according to the sensed threshold voltage of the driving transistor. In the image processing method of an organic light emitting display device including a plurality of pixels consisting of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel,
Converting the RGB data signal to R'G'B'W' data signal;
If the W' data signal among the information of the R'G'B'W' data signal has a gray level value other than 0 and one of the R'G'B' data signals has a gray level value of 0, the R' Substituting some gray scale values of the W' data signal among the G'B'W' data signals with gray scale values of the R'G'B' data signal among the R'G'B'W' data signals; and
Including outputting a final RGBW data signal,
The step of replacing some gray scale values of the W' data signal among the R'G'B'W' data signals with gray scale values of the R'G'B' data signal among the R'G'B'W' data signals, An image processing method for an organic light emitting display device, comprising converting the R'G'B'W' data signal so that there is no data signal with a gray level of 0 and generating the final RGBW data signal. According to clause 11,
The step of substituting a partial grayscale value of the W' data signal among the R'G'B'W' data signals with a grayscale value of the R'G'B' data signal among the R'G'B'W' data signals includes: An organic light emitting display device that replaces the gray level value of the W' data signal with the gray level value of the R'G'B' data signal in response to a replacement ratio of the W' data signal set based on the gray level value of the W' data signal. Image processing method. According to clause 12,
When the gray level value of the W' data signal is greater than a reference value, a portion of the gray level value of the W' data signal is replaced with the gray level value of the R'G'B' data signal according to a maximum substitution ratio,
If the gray level value of the W' data signal is less than the reference value, a portion of the gray level value of the W' data signal is converted into the R'G'B' data signal according to a replacement ratio proportional to the gray level value of the W' data signal. An image processing method for an organic light emitting display device that replaces grayscale values. According to clause 11,
The step of converting the RGB data signal into the R'G'B'W' data signal is,
extracting the W' data signal based on the RGB data signal;
extracting an R''G''B'' data signal having luminance and color coordinates corresponding to the W' data signal based on a data signal having a minimum gray level value among the RGB data signals; and
Subtracting the gray level value of the R''G''B'' data signal from the gray level value of the RGB data signal and adding the W' data signal to generate the R'G'B'W' data signal. Including, an image processing method of an organic light emitting display device.

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