KR102106558B1 - Organic light emitting display device and method for driving thereof - Google Patents

Abstract

An organic light emitting display device according to an aspect of the present invention to prevent color coordinate changes and afterimages due to deterioration of a white organic light emitting diode in an organic light emitting display device including a white subpixel, red, green having an organic light emitting device A display panel including a plurality of unit pixels composed of blue, and white sub-pixels; A four-color data conversion unit for converting red, green, and blue input data into red, green, blue, and white input data using a first look-up table (LUT); Red, green, blue, and white output data is generated by reflecting a predetermined gain value to the red, green, blue, and white input data, and the red, green, blue, and white output data is stored every set cumulative period. A deterioration compensator which accumulates and stores the red, green, and blue three-color ratio values according to the accumulated white output data and feeds them back to the four-color data conversion unit; And a panel driver configured to supply the red, green, blue, and white output data to corresponding subpixels so that a predetermined image is output through the display panel, wherein the four-color data conversion unit includes a color temperature of the white subpixel. It is characterized in that the first lookup table is updated based on the three-color color ratio value fed back to be a target color temperature.

Description

Organic light-emitting display device and driving method therefor {ORGANIC LIGHT EMITTING DISPLAY DEVICE AND METHOD FOR DRIVING THEREOF}

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device including a white sub-pixel.

Recently, with the development of multimedia, the importance of a flat panel display device has increased. In response to this, flat panel display devices such as liquid crystal display devices, plasma display devices, and organic light emitting display devices have been commercialized. Among these flat panel display devices, the organic light emitting display device has a high response speed and is self-emissive, and thus has no problem in viewing angle, and thus has attracted attention as a next-generation flat panel display device.

A typical organic light emitting display device includes sub-pixels of red (R), green (G), and blue (B) as one unit pixel, and various colors through three sub-pixels. It displays one video consisting of.

Recently, in order to increase the luminance of the unit pixel, a four-color organic light emitting display device in which a white (W) subpixel is added to the unit pixel has been developed. The four-color organic light emitting display device converts and displays red, green, and blue three-color input data into red, green, blue, and white four-color data.

The conventional four-color organic light emitting diode display always emits white sub-pixels when driving a white color, while selectively emitting two sub-pixels among red, green, and blue sub-pixels to obtain a desired white color. Will be implemented. At this time, red, green, blue, and white output data are recorded on a look-up table (LUT) for each of the red, green, and blue input data and the target color temperature.

The above-described conventional four-color organic light emitting display device is proposed on the assumption that the color coordinates of the white sub-pixels are uniform. However, in practice, the white organic light-emitting device included in the white sub-pixel may always deteriorate more quickly than other sub-pixels depending on the material properties and the emission time because it always emits light unlike other sub-pixels. Deterioration causes white luminance deterioration and color coordinate change.

Therefore, the conventional four-color organic light emitting display device has a problem that yellowish phenomenon occurs because the color coordinates (CIEx, CIEy) are shifted according to the deterioration of the white organic light emitting device, and the change of the color coordinates appears as an afterimage. .

The present invention has been devised to solve the above-mentioned problems, and an organic light emitting display device and a driving method thereof to prevent color coordinate changes and afterimages due to deterioration of a white organic light emitting device in an organic light emitting display device including white subpixels The technical task is to provide.

An organic light emitting display device according to an aspect of the present invention for achieving the above technical problem, a display panel including a plurality of unit pixels composed of red, green, blue, and white sub-pixels having an organic light emitting element; A four-color data conversion unit for converting red, green, and blue input data into red, green, blue, and white input data using a first look-up table (LUT); Red, green, blue, and white output data is generated by reflecting a predetermined gain value to the red, green, blue, and white input data, and the red, green, blue, and white output data is stored every set cumulative period. A deterioration compensator which accumulates and stores the red, green, and blue three-color ratio values according to the accumulated white output data and feeds them back to the four-color data conversion unit; And a panel driver configured to supply the red, green, blue, and white output data to corresponding subpixels so that a predetermined image is output through the display panel, wherein the four-color data conversion unit includes a color temperature of the white subpixel. It is characterized in that the first lookup table is updated based on the three-color color ratio value fed back to be a target color temperature.

A method of driving an organic light emitting display device according to another aspect of the present invention for achieving the above technical problem is an organic light emitting display device including a unit pixel composed of red, green, blue, and white subpixels having an organic light emitting element A method of driving, comprising: converting red, green, and blue input data into red, green, blue, and white input data using a first look-up table; Generating red, green, blue, and white output data by reflecting a predetermined gain value in the red, green, blue, and white input data; And accumulating and storing the red, green, blue, and white output data in a memory every set cumulative period. Calculating three color ratio values of red, green, and blue according to the accumulated white output data; And updating the first look-up table based on the calculated three-color color ratio value so that the color temperature of the white sub-pixel becomes a target color temperature.

According to the present invention, it is possible to compensate for deterioration of the organic light emitting device based on the accumulated data of each subpixel.

In addition, according to the present invention, the red, green, and blue three-color ratio values according to the accumulated data of the white sub-pixels are fed back, and the three-color input data is converted to four-color input data based on the fed back three-color ratio values. The color temperature of the white sub-pixel can be set as a target value by correcting the three-color ratio value to prevent the color coordinate change and the yellowish phenomenon due to the deterioration of the white organic light emitting device, and this is due to the color coordinate change It has the effect of preventing an afterimage.

1 is a view for explaining the configuration of an organic light emitting display device according to an embodiment of the present invention.
2 is a circuit diagram showing the structure of a pixel circuit according to an embodiment of the present invention.
3 is a block diagram schematically showing the configuration of a four-color data conversion unit in FIG. 2;
4 is a block diagram schematically showing the configuration of the deterioration compensation unit shown in FIG. 2.
5 is a graph for explaining a method for calculating a gain value according to a first embodiment of the present invention.
6 is a graph for explaining a method for calculating a gain value according to a second embodiment of the present invention.
7 is a graph for explaining a method for calculating a gain value according to a third embodiment of the present invention.
8 is a graph showing changes in color temperature before and after applying the color temperature correction technique according to the present invention.
9 is a flowchart illustrating a method of driving an organic light emitting diode display according to an exemplary embodiment of the present invention.
FIG. 10 is a flowchart showing a method of updating a first lookup table shown in FIG. 9.

The meaning of the terms described in this specification should be understood as follows.

It should be understood that a singular expression includes a plurality of expressions unless the context clearly defines otherwise, and the terms "first", "second", etc. are intended to distinguish one component from another component, The scope of rights should not be limited by these terms.

It should be understood that terms such as “include” or “have” do not preclude the presence or addition possibility of one or more other features or numbers, steps, actions, components, parts or combinations thereof.

It should be understood that the term “at least one” includes all possible combinations from one or more related items. For example, the meaning of “at least one of the first item, the second item, and the third item” means 2 of the first item, the second item, and the third item, as well as the first item, the second item, and the third item, respectively. Any combination of items that can be presented from more than one dog.

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

1 is a view for explaining the configuration of an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 1, an organic light emitting display device according to an exemplary embodiment of the present invention includes a display panel 100, a four-color data conversion unit 200, a deterioration compensation unit 250, a panel driving unit 300, and a memory unit ( 400).

The display panel 100 includes a plurality of unit pixels (Pixel), and each unit pixel includes a plurality of sub pixels (SP). The plurality of sub-pixels SP are formed in the pixel region defined by the plurality of gate lines GL and the plurality of data lines DL intersecting each other. In addition, a plurality of driving power lines PL1 to which driving voltages are supplied from the panel driving unit 300 are formed on the display panel 100 in parallel with each of the plurality of data lines DL.

Each of the plurality of subpixels SP may be any one of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel. One unit pixel displaying one image may include adjacent red subpixels, green subpixels, blue subpixels, and white subpixels, or may include red subpixels, green subpixels, and blue subpixels. Hereinafter, it will be described on the assumption that the single unit pixel is composed of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel.

Each of the plurality of subpixels SP includes an organic light emitting diode OLED and a pixel circuit PC.

The organic light emitting diode OLED is connected between the pixel circuit PC and the second driving power supply line PL2 to emit predetermined color light by emitting light in proportion to the amount of data current supplied from the pixel circuit PC. To this end, the organic light emitting diode OLED includes an anode electrode (or pixel electrode) connected to the pixel circuit PC, a cathode electrode (or reflective electrode) connected to the second driving power supply line PL2, and an anode electrode and a cathode. It includes a light emitting cell formed between the electrodes to emit light of any one of red, green, blue, and white. Here, the light emitting cell may be formed to have a structure of a hole transport layer / organic light emitting layer / electron transport layer or a structure of a hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection layer. Furthermore, a functional layer for improving the luminous efficiency and / or lifespan of the organic light emitting layer may be further formed in the light emitting cell.

The pixel circuit PC is a data voltage supplied from the panel driver 300 to the data line DL in response to a gate signal GS having a gate-on voltage level supplied from the panel driver 300 to the gate line GL ( Vdata) is supplied to the organic light emitting device (OLED). At this time, the data voltage Vdata has a voltage value compensated for the deterioration characteristics of the organic light emitting diode OLED. To this end, the pixel circuit PC is configured to include a switching transistor formed on a substrate by a thin film transistor forming process, a driving transistor, and at least one capacitor. Here, the switching transistor and the driving transistor may be a-Si TFT, poly-Si TFT, oxide TFT, organic TFT, and the like.

An example of such a pixel circuit PC is shown in FIG. 2. Hereinafter, the configuration of the pixel circuit PC will be briefly described with reference to FIG. 2.

2 is a circuit diagram showing the structure of a pixel circuit according to an embodiment of the present invention.

First, the switching transistor Tsw supplies the data voltage Vdata supplied to the data line DL according to the gate signal GS at the gate-on voltage level supplied to the gate line GL, and the gate electrode of the driving transistor Tdr. To supply.

The driving transistor Tdr is turned on according to the voltage between the gate and the source including the data voltage Vdata supplied from the switching transistor Tsw to control the data current Ioled flowing to the organic light emitting diode OLED.

The capacitor Cst is connected between the gate electrode and the source electrode of the driving transistor Tdr to charge the difference voltage between the gate and source of the driving transistor Tdr, and then switches the driving transistor Tdr according to the charged voltage.

The pixel circuit PC illustrated in FIG. 2 is only an example, and the number of transistors and capacitors constituting the pixel circuit PC may be variously modified.

Referring to FIG. 1 again, the four-color data conversion unit 200 inputs red and green colors based on a timing synchronization signal (TSS) input from an external system main body (not shown) or a graphics card (not shown). Red, green, and blue to be supplied to each of the red sub-pixels, green sub-pixels, blue sub-pixels, and white sub-pixels constituting one unit pixel based on the three-color input data (R, G, and B) of blue and blue. , And white 4-color input data (Ri, Gi, Bi, Wi) are generated.

In one embodiment, the four-color data conversion unit 200 uses the first look-up table (LUT) to red, green, and blue three-color input data (R, G, B) in red, It is converted into green, blue, and white four-color input data (Ri, Gi, Bi, Wi).

In particular, the four-color data conversion unit 200 according to the present invention, when it is determined that the white sub-pixel is deteriorated in the deterioration compensation unit 250, red, green, and feedback from the deterioration compensation unit 250 The first lookup table is updated so that the color temperature of the white sub-pixel is the target color temperature based on the blue three-color color ratio value (RGB Portion).

That is, in the case of the present invention, when it is determined that the deterioration of the white sub-pixel occurs, in the process of converting the three-color input data (R, G, B) into four-color input data (Ri, Gi, Bi, Wi) 3 By adjusting the color color ratio value, the color temperature of the white sub-pixel can be corrected so that the color temperature of the white sub-pixel becomes the target color temperature, thereby preventing an afterimage caused by a change in color coordinates.

A more detailed description of the four-color data conversion unit 200 according to an embodiment of the present invention will be described later with reference to FIG. 3.

The deterioration compensator 250 reflects a predetermined gain value in the red, green, blue, and white four-color input data Ri, Gi, Bi, and Wi output from the four-color data conversion unit 200, and red, Four colors of green, blue, and white output data (Ro, Go, Bo, Wo) are generated.

In particular, the deterioration compensation unit 250 according to the present invention accumulates and stores the four color output data (Ro, Go, Bo, Wo) of red, green, blue, and white in the memory unit 400 for each set cumulative period. , The three color ratio values of red, green, and blue according to the accumulated white output data are calculated and fed back to the four color data conversion unit 200.

A more detailed description of the deterioration compensation unit 250 according to an embodiment of the present invention will be described later with reference to FIG. 4.

The panel driver 300 generates a gate control signal GCS and a data control signal DCS based on the timing synchronization signal TSS, and generates a gate signal GS according to the gate control signal GCS to generate a gate line. In addition to sequentially supplying to (GL), the four-color output data (Ro, Go, Bo, Wo) supplied from the deterioration compensator 250 is converted into a data voltage (Vdata) according to the data control signal (DCS) to form a data line. (DL). To this end, the panel driving unit 300 includes a timing control unit 320, a gate driving circuit unit 330, and a data driving circuit unit 340.

The timing control unit 320 sets the driving timing of each of the gate driving circuit unit 330 and the data driving circuit unit 340 according to a timing synchronization signal (TSS) input from an external system body (not shown) or a graphic card (not shown). Control. That is, the timing control unit 320 is based on a timing synchronization signal (TSS) such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), a data enable signal (DE), a dot clock (DCLK), a gate control signal ( GCS) and a data control signal (DCS), and controls the driving timing of the gate driving circuit unit 330 through the gate control signal (GCS), and the data driving circuit unit 340 through the data control signal (DCS) to synchronize with this ) To control the driving timing.

In addition, the timing control unit 320 displays the red, green, blue, and white four-color output data (Ro, Go, Bo, Wo) supplied from the deterioration compensation unit 250 in a pixel arrangement structure of the display panel 100 And the aligned data DATA is supplied to the data driving circuit unit 340 based on a predetermined interface method.

Meanwhile, the timing control unit 320 may include the deterioration compensation unit 250. In this case, the deterioration compensator 250 may be built in the timing control unit 320, and in this case, may be built in a program form or a logic form.

The gate driving circuit unit 330 generates a gate signal GS corresponding to an image display order based on the gate control signal GCS supplied from the timing control unit 320 and supplies the gate signal GS to the corresponding gate line GL. . The gate driving circuit unit 330 may be formed in the form of a plurality of integrated circuits (ICs), or may be formed directly on a substrate of the display panel 100 together with the transistor forming process of each sub-pixel SP to form the plurality of gate lines. (GL) Each may be connected to one side or both sides.

The data driving circuit unit 340 receives data DATA and a data control signal DCS from the timing control unit 320 and receives a plurality of reference gamma voltages from an external reference gamma voltage supply unit (not shown). The data driving circuit unit 340 converts the alignment data DATA into an analog data voltage Vdata using a plurality of reference gamma voltages according to the data control signal DCS, and converts the converted data voltage Vdata. ) Is supplied to the data line DL of the sub-pixel SP. As such, the data driving circuit part 340 may be formed in a form of a plurality of integrated circuits (ICs) and connected to one side and / or both sides of the data line DL.

Hereinafter, the configuration of the four-color data conversion unit shown in FIG. 2 will be described in more detail with reference to FIG. 3.

3 is a block diagram schematically showing the configuration of a four-color data conversion unit according to an embodiment of the present invention.

As shown in FIG. 3, the four-color data conversion unit 200 according to an embodiment of the present invention includes a data conversion unit 201, a comparison unit 202, a correction amount calculation unit 203, and a table update unit ( 204).

First, the data conversion unit 201 uses red, green, and blue three-color input data (R, G, and B) so that the color temperature of the white sub-pixel becomes the target color temperature using the first look-up table 205 that is determined in advance. Is converted into red, green, blue, and white four-color input data (Ri, Gi, Bi, Wi).

In one embodiment, the first look-up table 205 records three-color input data (R, G, B) and a target three-color color ratio value to be applied for each target color temperature of a white sub-pixel. According to this embodiment, the data conversion unit 201 selects a target color ratio value matching the target color temperature of the three color input data (R, G, B) and the white sub-pixel on the first look-up table 205. Then, by applying the selected target color ratio value to the three-color input data (R, G, B), four-color input data (Ri, Gi, Bi, Wi) is generated.

The comparator 202 receives a three-color color ratio value (hereinafter referred to as “feedback three-color color ratio value”) fed back from the deterioration compensation unit 250. In addition, the comparison unit 202 compares the three-color color ratio value (hereinafter referred to as a 'target three-color color ratio value') that causes the color temperature of the white sub-pixel to become the target color temperature and is compared with the feedback three-color color ratio value. Calculate

The correction amount calculating unit 203 receives the deviation calculated by the comparing unit 202 from the comparing unit 202, and the deviation and the target color temperature calculated by the comparing unit 202 on the second look-up table 206. The corresponding three-color color ratio value correction amount is obtained. At this time, in the second look-up table 206, a correction amount of the three-color color ratio value to be applied for each target color temperature and deviation is recorded. Therefore, the correction amount calculating unit 203 extracts the correction amount of the three-color color ratio value matching the deviation and the target color temperature calculated by the comparison unit 202 on the second look-up table.

The table update unit 204 receives the three-color color ratio value correction amount from the correction amount calculation unit 203, and receives the received three-color color ratio value correction amount in the target three-color color ratio recorded in the first look-up table 205. The first lookup table is updated by correcting the target three-color color ratio value to reflect the value.

In the above-described embodiment, the table update unit 204 reflects the three-color color ratio value correction amount to the target three-color color ratio value recorded in the first look-up table 205 to correct the target three-color color ratio value. 1 It has been described that the lookup table 205 is updated.

However, in another embodiment, the data conversion unit 201 does not include a separate table update unit 204, and the data conversion unit 201 sets the three-color color ratio value correction amount to the target three-color color ratio value on the first look-up table 205. Four-color input data (Ri, Gi) by selecting another target three-color color ratio value having the same value as the reflected result value and applying the selected other target three-color color ratio value to the three-color input data (R, G, B) , Bi, Wi).

Hereinafter, the configuration of the deterioration compensation unit illustrated in FIG. 2 will be described in more detail with reference to FIG. 4.

4 is a block diagram schematically showing the configuration of a deterioration compensation unit according to an embodiment of the present invention.

4, the deterioration compensator 250 according to an embodiment of the present invention includes a data compensator 410, a data accumulator 420, an address controller 430, and a gain value calculator 440. , And an operation unit 450.

The data compensator 410 serializes the red image data, the green image data, the blue image data, and the white four-color input data (Ri, Gi, Bi, Wi) from the four-color data converter 200 in units of pixel units. Or, it is supplied in parallel.

The data compensator 410 generates four-color output data (Ro, Go, Bo, Wo) by reflecting a predetermined gain value in the received four-color input data (Ri, Gi, Bi, Wi).

In one embodiment, the data compensation unit 410 multiplies each of the predetermined gain values by the four color input data (Ri, Gi, Bi, Wi) of each sub-pixel to generate four color output data (Ro, Go, Bo, Wo).

At this time, the predetermined gain value may be generated by the gain value calculating unit 440 and stored in the memory unit 400. Accordingly, the data compensation unit 410 reads a predetermined gain value to be applied to the corresponding sub-pixel from the memory unit 400 and reflects it in the four-color input data Ri, Gi, Bi, and Wi of each sub-pixel.

In one embodiment, a predetermined gain value may be updated on a frame-by-frame basis. The predetermined gain value to be reflected first in the four-color input data (Ri, Gi, Bi, Wi) of each sub-pixel may be specified in advance or may be set to "1".

The data compensation unit 410 provides the generated four-color output data (Ro, Go, Bo, Wo) to the above-described panel driving unit 300, that is, the timing control unit 320.

The data accumulator 420 is a predetermined cumulative cycle of four color output data (Ro, Go, Bo, Wo) output from the data compensator 410 to compensate for the deterioration of the organic light emitting element included in each subpixel. Each is accumulated and stored in the memory unit 400.

That is, the data accumulator 420 reads the cumulative output data Adata of the corresponding subpixel SP corresponding to the output data Ro, Go, Bo, and Wo of each subpixel from the memory 400. ), And accumulate the output data (Ro, Go, Bo, Wo) again in the accumulated cumulative output data (Adata) of the corresponding sub-pixel (SP), and store them in the memory unit 400, so that each sub-pixel (SP) The output data Adata accumulated up to the current frame are stored in the memory unit 400.

The address control unit 430 designates the address of the memory unit 400 in which the output data of each sub-pixel generated by the data accumulation unit 420 is accumulated and stored. That is, the address control unit 430 controls a read operation or a write operation of the memory unit 400, and the data accumulation unit 420 is accumulated at a corresponding address of the memory unit 400. The read output data is read, and the accumulated output data of each newly generated sub-pixel by the data accumulation unit 420 is stored in a corresponding address of the memory unit 400.

The gain value calculator 440 accumulates and compensates for deterioration set every frame or a predetermined cycle based on the four color output data (Ro, Go, Bo, Wo) of red, green, blue, and white accumulated and stored in the memory unit 400. For each period, a gain value DCG for compensating deterioration according to a driving time (quantity) of the organic light emitting diode OLED included in each subpixel SP is calculated.

In one embodiment, the gain value calculating unit 440 compares the gain value calculated for each sub-pixel with the gain value of each sub-pixel that is pre-stored in the memory unit 400 and the pre-stored gain value and pre-stored When the gain value is different, the gain value stored in the memory unit 400 is updated to the newly calculated gain value. If the calculated gain value and the previously stored gain value are the same, the memory unit 400 is previously stored. Keep the gain value.

Hereinafter, a method of calculating the gain value for each sub-pixel by the gain value calculating unit 440 will be described in detail with reference to FIGS. 5 to 7.

5 is a graph for explaining a method for calculating a gain value according to the first embodiment of the present invention.

According to the first embodiment, the gain value calculating unit 440 determines the luminance A of each sub-pixel SP based on the accumulated output data of each sub-pixel SP stored in the memory unit 400. The gain value DCG of each sub-pixel SP for increasing to the set initial luminance Yint may be calculated. For example, the gain value calculating unit 440 compares the accumulated output data of the corresponding sub-pixel SP with the accumulated output data (Ref1, Ref2, Ref3) at a plurality of set compensation points, respectively. When the accumulated output data of the pixel SP is greater than or equal to the accumulated output data (Ref1, Ref2, Ref3) at each compensation time point, increase the luminance (A) of the sub-pixel (SP) to the set initial luminance (Yint) Calculate the gain value for DCG.

Each of the accumulated output data (Ref1, Ref2, Ref3) at the plurality of compensation points gradually has a large value to correspond to the set luminance deterioration value (Yset) compared to the initial luminance (Yint) of the organic light emitting diode (OLED). As the set prediction data, it may be set from a look-up table or a relational expression consisting of prediction data for a constant luminance deterioration point compared to the initial luminance Yint of the organic light emitting diode OLED.

The gain value calculator 440 includes a look-up table mapped with a gain value (DCG) having a real value greater than 1 according to the accumulated output data, or an accumulated output It may be composed of operation logic (Logic) for performing an operation to derive a gain value (DCG) having a real value (1) exceeding 1 according to the data.

As a result, in the case of the first embodiment, the gain value calculator 440 repeatedly performs the above-described process so that the accumulated output data of each sub-pixel SP is accumulated output data (Ref1, Ref2) at the compensation time point. , Ref3), a gain value (DCG) having a real value exceeding 1 is generated each time.

6 is a graph for explaining a method for calculating a gain value according to a second embodiment of the present invention.

As illustrated in FIG. 6, in the second embodiment, the gain value calculating unit 440 is based on the accumulated output data of each sub-pixel SP stored in the memory unit 400. The gain value DCG for reducing the luminance Y_SP of) to the same luminance as the luminance Y_ref of the subpixel having the most deteriorated organic light emitting diode OLED is calculated.

For example, in the second embodiment, the gain value calculating unit 440 is the maximum output data having the maximum value among the accumulated output data of all sub-pixels SP stored in the memory unit 400 (hereinafter, ' Maximum output data), and compares the extracted maximum output data with the accumulated output data (Ref1, Ref2, Ref3) at a plurality of set compensation points, and the maximum output data is accumulated at the compensation point. In the case of output data (Ref1, Ref2, Ref3) or more, the gain value DCG of each sub-pixel SP is calculated based on the difference value between the maximum output data and the accumulated output data of each sub-pixel SP.

Each of the accumulated output data (Ref1, Ref2, Ref3) at the plurality of compensation points is prediction data corresponding to the set luminance drop points (t1, t2, t3) compared to the initial luminance (Yint) of the organic light emitting diode (OLED). , It may be set from a look-up table or a relational expression that derives prediction data for a point in time at which a certain luminance decreases compared to an initial luminance (Yint) of the organic light emitting diode (OLED).

In the second embodiment, the gain value calculating unit 40 is a look-up table mapped with a gain value (DCG) having a real value less than 1 according to a difference value between the accumulated output data and the maximum output data ( Look-Up Table), or Logic that performs an operation to derive a gain value (DCG) having a real value less than 1 according to a difference value between accumulated output data and maximum output data. It can be done.

As a result, in the case of the second embodiment, the gain value calculating unit 440 repeatedly performs the above-described process, so that the maximum output data is greater than or equal to the accumulated output data (Ref1, Ref2, Ref3) at the time of compensation. A gain value (DCG) of each sub-pixel SP having a real value of less than 1 is generated according to a difference value between data and the accumulated output data of the sub-pixel SP to generate a gain value of each sub-pixel SP. The luminance Y_SP is adjusted to be equal to the luminance Y_ref of the reference subpixel SP having the maximum output data.

7 is a graph for explaining a method for calculating a gain value according to a third embodiment of the present invention.

As shown in FIG. 7, in the case of the third embodiment, the gain value calculating unit 440 is the maximum among the accumulated output data of all sub-pixels SP stored in the memory unit 400 at each degradation compensation time point. Data having a value (hereinafter referred to as 'maximum output data') is extracted and set as reference data, and a cumulative difference value between accumulated output data of each sub-pixel (Y_ref) is calculated based on the set reference data, and calculated The gain value DCG of each sub-pixel SP may be calculated according to the accumulated difference value of each sub-pixel SP. Here, the gain value DCG of each sub-pixel SP is set such that the luminance (Y_SP1, Y_SP2) of the sub-pixels having the cumulative difference value is reduced to the luminance (Y_ref) of the sub-pixels having the maximum output data. For example, the gain value DCG of each sub-pixel SP may be set to a real value less than 1 that exceeds 0. The gain value DCG of each sub-pixel SP is calculated differently according to the cumulative difference value of each sub-pixel SP, and is updated to a new value for each deterioration compensation point by the above-described calculation process.

The gain value calculator 440 may calculate the gain value DCG of each sub-pixel SP using various algorithms in addition to the method of calculating the gain value DCG according to the above-described embodiment.

Referring back to FIG. 4, the calculator 450 reads accumulated white output data from the memory unit 400 and determines whether the accumulated white output data is greater than or equal to a threshold. In one embodiment, the threshold value may be set as prediction data corresponding to a point in time when the luminance of the white sub-pixel decreases relative to the initial luminance. That is, the threshold value is set as the experimentally calculated cumulative white output data at the time when the yellowish phenomenon occurs as the color coordinates (CIEx, CIEy) are shifted as the white organic light emitting device of the white sub-pixel is deteriorated. Can be.

If it is determined that the accumulated white output data is greater than or equal to the threshold, the calculator 450 calculates the red, green, and blue three-color color ratio values according to the accumulated white input data, and calculates the calculated three-color color ratio values 4 Feedback to the color data conversion unit 200.

In one embodiment, the calculator 450 may calculate three color ratio values of red, green, and blue according to the accumulated white input data using Equation 1 below.

In Equation 1, rL, gL, and bL represent color ratios of red, green, and blue, respectively, and rX, rY, and rZ are red X, Y, and red, included in the accumulated white output data on the color coordinate. And Z coordinates, gX, gY, and gZ represent green X, Y, and Z coordinates included in the accumulated white output data on the color coordinates, and bX, bY, and bZ are accumulated white on the color coordinates. The blue X, Y, and Z coordinates included in the output data are represented, and wX, wY, and wZ represent X, Y, and Z coordinates of accumulated white output data on color coordinates.

As described above, the organic light emitting diode display and driving method according to an embodiment of the present invention compensate for the deterioration of the organic light emitting device based on the accumulated output data of each subpixel, and the white color of each unit pixel When the accumulated output data of a pixel is greater than or equal to a threshold value, it is determined that deterioration has occurred in the white sub-pixel, and based on the accumulated output data of the white sub-pixels of each unit pixel, the three color ratio values of red, red and blue Is calculated and fed back to the four-color data conversion unit, when converting the three-color input data (R, G, B) into four-color input data (Ri, Gi, Bi, Wi), the white sub-pixel is adjusted by adjusting the three-color color ratio ratio value. It is possible to correct the color temperature of the white sub-pixel so that the color temperature of the target becomes the target color temperature, thereby preventing the color coordinate change and yellowish phenomenon caused by the deterioration of the white organic light emitting device, as well as preventing the color coordinate change. A residual image caused by can be prevented.

8 is a graph showing changes in color temperature before and after applying the color temperature correction technique according to the present invention.

As can be seen in FIG. 8, in the process of converting the three-color input data (R, G, B) into four-color input data (Ri, Gi, Bi, Wi), the color temperature of the white sub-pixel becomes the target color temperature. When the color color ratio value is corrected, it can be seen that the color temperature is improved compared to before the correction.

Hereinafter, a driving method of the organic light emitting display device according to the present invention will be described with reference to FIG. 9.

9 is a flowchart illustrating a method of driving an organic light emitting diode display according to an exemplary embodiment of the present invention.

First, as shown in FIG. 9, red, green, and blue three-color input data R, G, and B are received (S900).

Thereafter, the three-color input data (R, G, B) is converted into red, green, blue, and white four-color input data (Ri, Gi, Bi, Wi) using the first lookup table (S910).

In one embodiment, the first look-up table records three-color input data (R, G, B) and target three-color color ratio values to be applied for each target color temperature of the white sub-pixel. According to this embodiment, the target color ratio value matching the target color temperature of the white color sub-pixel and the three-color input data (R, G, B) on the first lookup table is selected, and the selected target color ratio value is three colors By applying to the input data (R, G, B), four-color input data (Ri, Gi, Bi, Wi) is generated.

Thereafter, it is determined whether there is an update of the gain value to be reflected in the four-color input data (Ri, Gi, Bi, Wi) (S920). As a result of determination, if there is no update of the gain value, the gain value generated in the previous frame is reflected in the four-color input data (Ri, Gi, Bi, Wi) to generate four-color output data (Ro, Go, Bo, Wo). (S925), when the gain value is updated, the updated gain value is reflected in the four-color input data (Ri, Gi, Bi, Wi) to generate four-color output data (Ro, Go, Bo, Wo) (S930) ).

At this time, the gain values to be reflected first in the four-color input data (Ri, Gi, Bi, Wi) may be preset and stored in the memory unit.

Subsequently, the output data of the accumulated sub-pixels up to the previous frame previously stored in the corresponding address of the memory unit in which the red, green, blue, and white four-color output data (Ro, Go, Bo, Wo) are to be stored, respectively. After reading (S940), the four-color output data (Ro, Go, Bo, Wo) generated in S930 and the output data of each sub-pixel read in S940 are summed and stored again in the corresponding address in the memory ( S950). Accordingly, output data of each sub-pixel accumulated up to the current frame is recorded at a corresponding address in the memory unit.

Thereafter, the accumulated output data of the white sub-pixels up to the current frame stored in the memory unit is read (S960), and it is determined whether the accumulated output data of the white sub-pixels is greater than or equal to a threshold (S970). .

As a result of determination in S970, if the accumulated output data of the white sub-pixel is greater than or equal to a threshold value, it is determined that deterioration has occurred in the white sub-pixel, and the three color ratio values of red, green, and blue from the accumulated output data of the white sub-pixel Calculate (S980). At this time, the three-color color ratio value can be calculated using Equation 1 above.

In one embodiment, the threshold value may be set as prediction data corresponding to a point in time when the luminance of the white sub-pixel decreases relative to the initial luminance. That is, the threshold value is set as the experimentally calculated cumulative white output data at the time when the yellowish phenomenon occurs as the color coordinates (CIEx, CIEy) are shifted as the white organic light emitting device of the white sub-pixel is deteriorated. Can be.

Thereafter, after updating the first lookup table based on the three-color color ratio value calculated in S980 so that the color temperature of the white sub-pixel becomes the target color temperature (S990), newly input three-color input data (R, G, B) Repeat the above-described process for.

In one embodiment, the first look-up table records the target three-color color ratio values, which are the color ratio values of red, green, and blue, such that the color temperature of the white sub-pixel becomes the target color temperature, and the calculated three-color color ratio value The first lookup table can be updated by correcting the target three-color color ratio value recorded in the first lookup table based on.

Meanwhile, although not illustrated in FIG. 9, the driving method of the organic light emitting diode display according to the present invention is applied to accumulated red, green, blue, and white output data to compensate for deterioration of the organic light emitting elements included in each subpixel. Based on this, a gain value is calculated for each sub-pixel, and the calculated gain value is compared with a gain value of each sub-pixel pre-stored in the memory unit, and the gain value of each sub-pixel pre-stored in the memory unit according to the comparison result It may further include the process of updating.

The method of calculating the gain value of each sub-pixel is described above with reference to FIGS. 5 to 7, so a detailed description is omitted.

Hereinafter, a method of updating the first lookup table will be described with reference to FIG. 10.

10 is a flowchart illustrating a first lookup table update method according to an embodiment of the present invention.

First, as shown in FIG. 10, a deviation is obtained by comparing a three-color color ratio value calculated from accumulated output data of a white sub-pixel and a target three-color color ratio value such that the color temperature of a white sub-pixel becomes the target color temperature. Calculate (S1000).

Thereafter, on the second look-up table, a correction amount of the three-color color ratio value corresponding to the deviation and the target color temperature calculated in S1000 is selected (S1100). At this time, in the second look-up table 206, a correction amount of the three-color color ratio value to be applied for each target color temperature and deviation is recorded. Accordingly, the correction amount of the three-color color ratio value matching the target color temperature and the deviation calculated in S1100 is extracted on the second look-up table.

Thereafter, the first lookup table is updated by reflecting the correction amount of the three-color color ratio value to the target three-color color ratio value (S1200).

In the above-described embodiment, it has been described that the first lookup table is updated by correcting the target three color color ratio value by reflecting the amount of correction of the three color color ratio values to the target three color color ratio values recorded in the first lookup table.

However, in another embodiment, on the first look-up table, a target 3 color color ratio value having the same value as a result value reflecting a 3 color color ratio value correction amount to a target 3 color color ratio value is selected, and the selected other target 3 It is also possible to generate four-color input data (Ri, Gi, Bi, Wi) by applying the color color ratio values to the three-color input data (R, G, B).

The above-described driving method of the organic light emitting display device may also be implemented in a program form that can be performed using various computer means. At this time, the program for performing the driving method of the organic light emitting display device may include a hard disk, a CD-ROM, It is stored in a computer readable recording medium such as a DVD, ROM, RAM, or flash memory.

Those skilled in the art to which the present invention pertains will understand that the above-described present invention can be implemented in other specific forms without changing its technical spirit or essential features. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

The scope of the present invention is indicated by the following claims rather than the above detailed description, and it should be interpreted that all changes or modifications derived from the meaning and scope of the claims and equivalent concepts are included in the scope of the present invention. do.

100: display panel 200: 4-color data conversion unit
250: deterioration compensation unit 300: panel driving unit
201: data conversion unit 202: comparison unit
203: correction amount calculation unit 204: table update unit
205: first lookup table 206: second lookup table
400: memory unit 410: data compensation unit
420: data accumulation unit 430: address control unit
440: gain value calculation unit 450: operation unit

Claims (10)

A display panel including a plurality of unit pixels composed of red, green, blue, and white subpixels having an organic light emitting element;
A four-color data conversion unit for converting red, green, and blue input data into red, green, blue, and white input data using a first look-up table (LUT);
Red, green, blue, and white output data is generated by reflecting a predetermined gain value to the red, green, blue, and white input data, and the red, green, blue, and white output data is stored every set cumulative period. A deterioration compensator which accumulates and stores the red, green, and blue three-color ratio values according to the accumulated white output data and feeds them back to the four-color data conversion unit; And
And a panel driver configured to supply the red, green, blue, and white output data to corresponding sub-pixels so that a predetermined image is output through the display panel,
The four-color data conversion unit updates the first look-up table based on the three-color color ratio value fed back so that the color temperature of the white sub-pixel becomes a target color temperature,
The deterioration compensator determines whether the accumulated white output data is greater than or equal to a threshold value, and when the accumulated white output data is greater than or equal to a threshold value, three colors of red, green, and blue colors according to the accumulated white input data And a calculation unit which calculates a ratio value and feeds it back to the four-color data conversion unit. According to claim 1,
In the first look-up table, the target three-color color ratio values, which are the color ratio values of red, green, and blue, are recorded so that the color temperature of the white sub-pixel becomes the target color temperature,
The four-color data conversion unit, the organic light emitting display device, characterized in that for correcting the target three-color color ratio value recorded on the first look-up table based on the feedback three-color color ratio value. According to claim 1,
The four-color data conversion unit,
A comparison unit that compares the feedback three-color color ratio value and a target three-color color ratio value so that the color temperature of the white sub-pixel becomes the target color temperature;
A correction amount calculating unit for calculating a correction amount of the three-color color ratio value corresponding to the deviation and the target color temperature calculated by the comparison unit on a second look-up table; And
And a table update unit which updates the first look-up table by reflecting the correction amount of the three-color color ratio value to the target three-color color ratio value. According to claim 1,
The deterioration compensation unit,
In order to compensate for deterioration of the organic light emitting device included in each sub-pixel, a gain value calculating unit for calculating the predetermined gain value for each sub-pixel based on the accumulated red, green, blue, and white output data An organic light emitting display device, characterized in that. delete A driving method of an organic light emitting display device comprising a unit pixel composed of red, green, blue, and white subpixels having an organic light emitting element,
Converting red, green, and blue input data into red, green, blue, and white input data using the first look-up table;
Generating red, green, blue, and white output data by reflecting a predetermined gain value in the red, green, blue, and white input data; And
Accumulating and storing the red, green, blue, and white output data in a memory every set cumulative period;
It is determined whether the accumulated white output data is greater than or equal to a threshold value, and when the accumulated white output data is greater than or equal to a threshold value, three color ratio values of red, green, and blue according to the accumulated white output data are calculated. step; And
And updating the first look-up table based on the calculated three-color color ratio value so that the color temperature of the white sub-pixel becomes a target color temperature. The method of claim 6,
In the first look-up table, the target three-color color ratio values, which are the color ratio values of red, green, and blue, are recorded so that the color temperature of the white sub-pixel becomes the target color temperature,
In the updating step, a method of driving an organic light emitting display device, wherein the target three-color color ratio value is recorded in the first look-up table based on the calculated three-color color ratio value. The method of claim 6,
The updating step,
Calculating a deviation by comparing the calculated three-color color ratio value with a target three-color color ratio value such that the color temperature of the white sub-pixel becomes the target color temperature;
Calculating a correction amount of a three-color color ratio value corresponding to the calculated deviation and the target color temperature on a second look-up table; And
And updating the first look-up table by reflecting the correction amount of the three-color color ratio value to the target three-color color ratio value. The method of claim 6,
In the generating step, the predetermined gain value is calculated for each sub-pixel based on the accumulated red, green, blue, and white output data to compensate for deterioration of the organic light-emitting device included in each sub-pixel. Method of driving an organic light emitting display device, characterized in that. delete

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