KR101596962B1 - Organic Light Emitting Display Device - Google Patents

Abstract

The present invention relates to a display panel, A scan driver for supplying a scan signal to the display panel; And a gamma unit for changing the first gamma reference voltage value standardized for each gradation to a target second gamma reference voltage value by referring to the variation coefficient value supplied from the outside and mapping the second gamma reference voltage value to the data signal And an organic light emitting display device.

Organic electroluminescent display, gamma, coefficient

Description

[0001] The present invention relates to an organic light emitting display device,

An embodiment of the present invention relates to an organic light emitting display.

An organic electroluminescent device used in an organic electroluminescent display device is a self-luminous device in which a light emitting layer is formed between two electrodes located on a substrate. The organic light emitting display device may be a top emission type, a bottom emission type or a dual emission type depending on a direction in which light is emitted. It is divided into a passive matrix and an active matrix depending on the driving method.

The subpixel disposed in the organic light emitting display includes a transistor portion including a switching transistor, a driving transistor and a capacitor, and an organic light emitting diode including a lower electrode connected to the driving transistor included in the transistor portion, an organic light emitting layer, and an upper electrode .

In the organic light emitting display, when a scan signal, a data signal, a power supply, and the like are supplied to a plurality of subpixels arranged in a matrix form, the selected subpixel emits light, thereby displaying an image.

In general, an organic light emitting display device displays a screen by referring to a gamma value stored in a memory every time the gamma value is corrected (color correction) to store a corrected gamma value in a memory to display a desired luminance and a color coordinate, . However, the organic light emitting display device has a disadvantage in that it is difficult to implement more than one gamma due to the memory capacity limitation, and it is difficult to store the newly measured and corrected gamma values in the memory when adjustment of the stored gamma values is required.

According to an aspect of the present invention, a gamma reference voltage value can be changed using only a variation coefficient input from the outside, so that various multi-gamma implementations can be realized with a minimized register command And an organic electroluminescent display device.

According to the present invention, there is provided a display panel comprising: a display panel; A scan driver for supplying a scan signal to the display panel; And a gamma unit for changing the first gamma reference voltage value standardized for each gradation to a target second gamma reference voltage value by referring to the variation coefficient value supplied from the outside and mapping the second gamma reference voltage value to the data signal And an organic light emitting display device.

The gamma unit includes a memory unit storing a first gamma reference voltage value, a first gamma reference voltage value storage unit storing a first gamma reference voltage value stored in the memory unit and referring to the variation coefficient value, To the second gamma reference voltage value.

The first gamma reference voltage value may be stored in the memory unit in a state in which the target brightness value is reflected.

The target luminance value is made up of the first gamma reference voltage value x the maximum luminance value, and the arithmetic operation unit calculates the first gamma reference voltage value using the gamma equation including the variation coefficient value, the maximum luminance value and the first gamma reference voltage value To a second gamma reference voltage value.

The first gamma reference voltage value may be a 2.2 gamma reference voltage value and the second gamma reference voltage value may be a 1.0 gamma reference voltage value, a 1.8 gamma reference voltage value, and a 2.5 gamma reference voltage value.

The first gamma reference voltage value may be a 1.0 gamma reference voltage value and the second gamma reference voltage value may be a 1.8 gamma reference voltage value, a 2.2 gamma reference voltage value, and a 2.5 gamma reference voltage value.

The first gamma reference voltage value may be a 1.8 gamma reference voltage value and the second gamma reference voltage value may be a 1.0 gamma reference voltage value, a 2.2 gamma reference voltage value, and a 2.5 gamma reference voltage value.

The first gamma reference voltage value may be a 2.5 gamma reference voltage value and the second gamma reference voltage value may be a 1.0 gamma reference voltage value, a 1.8 gamma reference voltage value, and a 2.2 gamma reference voltage value.

The present invention provides an organic electroluminescent display device capable of changing digital video data into analog video data mapped to a target gamma reference voltage value according to a variation coefficient value. In addition, since the embodiment can change the gamma reference voltage value only by using the variation coefficient input from the outside, various multi-gamma implementations can be realized with a minimized register command. In addition, since the embodiment changes the gamma reference voltage value by using an arithmetic operation method, selective gamma can be realized without expanding the internal or external memory part.

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

FIG. 1 is a block diagram of an organic light emitting display according to an exemplary embodiment of the present invention, and FIG. 2 is a diagram illustrating a circuit configuration of the subpixel shown in FIG.

1 and 2, an organic light emitting display according to an exemplary embodiment of the present invention includes a timing driver TCN, a display panel PNL, a data driver DDRV, and a scan driver SDRV.

The timing driver TCN supplies system signals such as digital video data DRGB, a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE and a clock CLK from the outside Receive. The timing driver TCN includes a driving signal such as a data control signal SOE or POL for controlling the data driver DDRV using an externally supplied system signal and a driving signal for controlling the operation timing of the scan driver SDRV Gate timing control signals (GSP, GSC, GOE), and the like.

The data driver DDRV samples and latches the digital video data DRGB input from the timing controller TCN in response to the driving signals SOE and POL output from the timing controller TCN and converts the digital video data DRGB into data of a parallel data system do. The data driver DDRV includes a shift register for receiving the horizontal synchronization signal Hsync and a latch for storing the digital video data DRGB by referring to the signal received from the shift register. The data driver DDRV converts the digital video data DRGB converted into the parallel data transmission scheme into the analog video data using the gamma unit GAMM and supplies the analog video data to the data lines DL1 to DLn. The gamma unit GAMM includes a memory unit MEM, a calculation unit PLOG, and a gamma voltage generator. The gamma unit GAMM changes the first gamma reference voltage value stored in the memory unit MEM to a target second gamma reference voltage value with reference to the variation coefficient value ExK supplied from the outside, Value and the data signal. Accordingly, the digital video data DRGB supplied from the timing controller TCN can supply the analog video data mapped to the target gamma reference voltage value to the data lines DL1 to DLn.

The scan driver SDRV generates a scan signal in response to the gate signals GSP, GSC, and GOE output from the timing driver TCN and supplies the scan signals to the scan lines SL1 to SLm.

The display panel PNL includes subpixels SP arranged in a matrix form at intersections of the data lines DL1 to DLn and the scan lines SL1 to SLm. The subpixels SP may be formed of a 2T (Capacitor) structure including a switching transistor, a driving transistor, a capacitor, and an organic light emitting diode, or may have a structure in which a transistor and a capacitor are further added.

In the case of the 2T1C structure, the elements included in the subpixel SP can be connected as shown in FIG. In the switching transistor S1, a gate is connected to a scan line SL1 to which a scan signal is supplied, one end is connected to the data line DL1 to which a data signal is supplied, and the other end is connected to the first node A. [ The driving transistor Tl is connected at one end to a second node B connected to the first power supply line VDD to which a gate is connected to the first node A and a power supply of high potential is supplied, The other end is connected. One end of the capacitor Cst is connected to the first node A and the other end is connected to the second node B. The cathode of the organic light emitting diode D is connected to a second power supply line GND to which the anode is connected to the other end of the driving transistor Tl and the third node C and to which a low potential power is supplied.

In the above description, the transistors S1 and T1 included in the sub-pixel SP have been described as P-type, but the embodiment of the present invention is not limited thereto. The power supply having a high potential supplied through the first power supply line VDD may be higher than the power supply having a low potential supplied through the second power supply line GND and the first power supply line VDD and the second power supply line GND) can be switched according to the driving method.

The above-described subpixel SP can operate as follows. When the scan signal is supplied through the scan line SL1, the switching transistor S1 is turned on. Next, when the data signal supplied through the data line DL1 is supplied to the first node A through the turned-on switching transistor S1, the data signal is stored as a data voltage in the capacitor Cst. Next, when the scan signal is interrupted and the switching transistor S1 is turned off, the driving transistor T1 is driven in response to the data voltage stored in the capacitor Cst. Next, when the high-potential power supplied through the first power line VDD flows through the second power line GND, the organic light-emitting diode D emits light. However, this is only an example of the driving method, and the embodiment of the present invention is not limited thereto.

Hereinafter, an organic light emitting display according to an embodiment of the present invention will be described in more detail.

FIGS. 3 to 5 are gamma curve graphs for explaining color correction and gamma value setting of an organic light emitting display according to an exemplary embodiment of the present invention. FIG. Fig. 7 is a schematic block diagram of a data driver for explaining the device.

In an organic light emitting display device manufactured by a conventional method, there are variations in process and deviation of organic materials. Accordingly, the fabricated organic light emitting display device improves the deviation through a color correction process. The color correction method uses a method of adjusting the gamma curve so that the target luminance, the color coordinate, and the gamma value can be displayed on a panel-by-spec display quality basis.

In the embodiment, as shown in FIG. 3, the highest level of RGB is corrected to control the color coordinates, white balance, and brightness, and the black level of RGB is corrected as shown in FIG. 4, and the inclination is corrected as shown in FIG. Since the organic electroluminescent display uses independent gamma, the above correction is performed for each of RGB, and the standardized first gamma reference voltage value for each gradation is stored in the memory unit MEM. Therefore, the memory unit MEM occupies a capacity 21 bytes corresponding to the gamma value 3ea for each of R, G, and B and the correction value (7 points) for the correction of Figures 3 to 5, and the first gamma reference voltage value .

In the embodiment, a first gamma reference voltage value corresponding to the characteristics of each display panel PNL is stored in the memory unit MEM to indicate RGB luminance, gamma curve, and white luminance for various gamma values desired. The first gamma reference voltage value stored in the memory unit MEM is changed to a second gamma reference voltage value using a gamma unit (GAMM), and the changed second gamma reference voltage value is mapped to a data signal. .

The gamma unit GAMM includes a memory unit MEM, a calculator PLOG, and a gamma voltage generator VGEN as shown in FIG. The memory unit MEM stores the first gamma reference voltage value corrected in the same manner as in FIGS. 3 through 5 and standardized for each gray level. The operation unit PLOG calculates a standardized first gamma reference voltage value for each gradation, and calculates a desired gradation, a gamma value and a luminance value for the desired gamma.

Here, the first gamma reference voltage value normalized for each gradation is calculated as " ^{( gamma )} / ^{gamma ( gamma ) &} quot ;, and the first gamma reference voltage value is a value (MEM). Here, the target luminance value is calculated as "maximum luminance value ExL x first gamma reference voltage value (Normalized Gamma Value) ". On the other hand, the operation unit PROG uses the "Gamma calculation formula (ExK x ExL x Normalized Gamma Value)" including the variation coefficient value ExK, the maximum luminance value ExL and the first gamma reference voltage value Thereby changing the first gamma reference voltage value to the second gamma reference voltage value.

In the above description, the variation coefficient value (ExK) is defined as a value calculated according to the error between the calculated value and the actual measured value in consideration of the characteristic difference between the display panels (PNL). When the gamma is changed, Coefficient. The maximum luminance value ExL is a value that can be varied according to the specification (or the user demand), and corresponds to a luminance value that can be expressed by the gamma reference voltage value normalized for each gray level.

The operation unit PLOG invokes the first gamma reference voltage value stored in the memory unit MEM and transfers the gamma register G_reg to the gamma voltage generation unit VGEN with reference to the variation coefficient value ExK. Then, the gamma voltage generator VGEN transmits the gamma voltage VG of V0 to V255 to the digital-analog converter DAC so as to be mapped to the data signal DRGB changed to the second gamma reference voltage value. Then, the digital-to-analog converter DAC converts the digital video data signal DRGB to a second gamma reference voltage value, converts the digital video data signal DRGB into an analog video data signal ARGB, and outputs it to the output buffer OP- .

Table 1 is a table showing a first gamma reference voltage value (Normalized Gamma Value) standardized for each gradation, and Table 2 is a table showing an example of an actual set value with respect to a gamma calculation value.

The operation unit PLOG according to the embodiment changes the first gamma reference voltage values normalized to 1.0 gamma, 1.8 gamma, 2.2 gamma, 2.5 gamma, etc. according to the variation coefficient value (ExK) as shown in Table 1, Multi-gamma implementation is possible.

Hereinafter, a method of selecting a gamma reference voltage according to a variation coefficient value will be described, but the variation coefficient value ExK is expressed as (1) to (3) in order to facilitate understanding of the explanation.

FIGS. 7 through 10 illustrate a multi-gamma implementation according to an embodiment of the present invention.

FIG. 7 illustrates an example in which the first gamma reference voltage value stored in the memory unit MEM is stored at 2.2 gamma. In the case of the embodiment, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (1), the data driver DDRV sets the first gamma reference voltage value set to 2.2 gamma to the second gamma reference voltage And the digital video data (DRGB) is changed to analog video data (ARGB) in accordance with 1.8 gamma. Alternatively, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (2), the data driver DDRV sets the first gamma reference voltage value set to 2.2 gamma to a second gamma reference voltage value And the digital video data DRGB is changed to the analog video data ARGB corresponding to 1.0 gamma. Alternatively, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (3), the data driver DDRV sets the first gamma reference voltage value set to 2.2 gamma to a second gamma reference voltage value And the digital video data DRGB is changed to the analog video data ARGB corresponding to 2.5 gamma.

8 shows an example in which the first gamma reference voltage value stored in the memory unit MEM is stored at 1.8 gamma. In the case of the embodiment, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (1), the data driver DDRV sets the first gamma reference voltage value set to 1.8 gamma to the second gamma reference voltage And the digital video data (DRGB) is changed to the analog video data (ARGB) in accordance with 1.0 gamma. Alternatively, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (2), the data driver DDRV sets the first gamma reference voltage value set to 1.8 gamma to a second gamma reference voltage value And the digital video data DRGB is changed to the analog video data ARGB corresponding to 2.5 gamma. Alternatively, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (3), the data driver DDRV sets the first gamma reference voltage value set to 1.8 gamma to a second gamma reference voltage value And the digital video data DRGB is changed to the analog video data ARGB corresponding to 2.2 gamma.

9 shows an example in which the first gamma reference voltage value stored in the memory unit MEM is stored at 1.0 gamma. In the case of the embodiment, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (1), the data driver DDRV sets the first gamma reference voltage value set to 1.0 gamma to the second gamma reference voltage And the digital video data (DRGB) is changed to analog video data (ARGB) in accordance with 2.5 gamma. Alternatively, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (2), the data driver DDRV sets the first gamma reference voltage value set to 1.0 gamma to the second gamma reference voltage value And the digital video data DRGB is changed to the analog video data ARGB corresponding to 2.2 gamma. Alternatively, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (3), the data driver DDRV sets the first gamma reference voltage value set to 1.0 gamma to a second gamma reference voltage value And the digital video data DRGB is changed to analog video data ARGB corresponding to 1.8 gamma.

10 illustrates an example in which the first gamma reference voltage value stored in the memory unit MEM is stored at 2.5 gamma. In the case of the embodiment, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (1), the data driver DDRV sets the first gamma reference voltage value set to 2.5 gamma to the second gamma reference voltage And the digital video data (DRGB) is changed to the analog video data (ARGB) in accordance with 2.2 gamma. Alternatively, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (2), the data driver DDRV sets the first gamma reference voltage value set to 2.5 gamma to a second gamma reference voltage value And the digital video data DRGB is changed to analog video data ARGB corresponding to 1.8 gamma. Alternatively, when the variation coefficient value ExK input to the operation unit PLOG is, for example, (3), the data driver DDRV sets the first gamma reference voltage value set to 2.5 gamma to a second gamma reference voltage value And the digital video data DRGB is changed to the analog video data ARGB corresponding to 1.0 gamma.

As described above, the present invention provides an organic light emitting display device capable of changing digital video data into analog video data mapped to a target gamma reference voltage value according to a variation coefficient value. In addition, since the embodiment can change the gamma reference voltage value only by using the variation coefficient input from the outside, various multi-gamma implementations can be realized with a minimized register command. In addition, since the embodiment changes the gamma reference voltage value by using an arithmetic operation method, selective gamma can be realized without expanding the internal or external memory part.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

1 is a block diagram of an organic light emitting display according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an exemplary circuit configuration of the subpixel shown in FIG. 1; FIG.

3 to 5 are gamma curve graphs for explaining color correction and gamma value setting of an organic light emitting display according to an embodiment of the present invention.

FIG. 6 is a schematic block diagram of a data driver for explaining an organic light emitting display according to an embodiment of the present invention; FIG.

Figures 7 to 10 illustrate a multi-gamma implementation in accordance with an embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

TCN: timing driver PNL: display panel

DDRV: Data driver SDRV: Scan driver

MEM: Memory part PLOG: Operation part

SP: sub-pixel DAC: digital-analog conversion unit

Claims (8)

Display panel; A scan driver for supplying a scan signal to the display panel; And A first gamma reference voltage value that is standardized for each gradation is changed to a target second gamma reference voltage value by referring to a variation coefficient value supplied from the outside and a gamma unit for mapping the second gamma reference voltage value to a data signal And a driving unit, The first gamma reference voltage value is a 2.2 gamma reference voltage value, Wherein the second gamma reference voltage value is one of a 1.0 gamma reference voltage value, a 1.8 gamma reference voltage value, and a 2.5 gamma reference voltage value. The method according to claim 1, The gamma- A memory unit for storing the first gamma reference voltage value, The first gamma reference voltage value stored in the memory unit is referred to and the first gamma reference voltage value is referenced to the target second gamma reference voltage value by referring to the variation coefficient value An organic electroluminescent display device according to the present invention. 3. The method of claim 2, Wherein the first gamma reference voltage value is stored in the memory unit in a state in which the target luminance value is reflected. The method of claim 3, Wherein the target luminance value comprises the first gamma reference voltage value x the maximum luminance value, The arithmetic operation unit may include an organic electroluminescence (EL) device that changes the first gamma reference voltage value to the second gamma reference voltage value using a gamma equation including the variation coefficient value, the maximum luminance value, and the first gamma reference voltage value. Display device. delete Display panel; A scan driver for supplying a scan signal to the display panel; And A first gamma reference voltage value that is standardized for each gradation is changed to a target second gamma reference voltage value by referring to a variation coefficient value supplied from the outside and a gamma unit for mapping the second gamma reference voltage value to a data signal And a driving unit, Wherein the first gamma reference voltage value is a 1.0 gamma reference voltage value, Wherein the second gamma reference voltage value is any one of a 1.8 gamma reference voltage value, a 2.2 gamma reference voltage value, and a 2.5 gamma reference voltage value. Display panel; A scan driver for supplying a scan signal to the display panel; And A first gamma reference voltage value that is standardized for each gradation is changed to a target second gamma reference voltage value by referring to a variation coefficient value supplied from the outside and a gamma unit for mapping the second gamma reference voltage value to a data signal And a driving unit, The first gamma reference voltage value is a 1.8 gamma reference voltage value, Wherein the second gamma reference voltage value is any one of a 1.0 gamma reference voltage value, a 2.2 gamma reference voltage value, and a 2.5 gamma reference voltage value. Display panel; A scan driver for supplying a scan signal to the display panel; And A first gamma reference voltage value that is standardized for each gradation is changed to a target second gamma reference voltage value by referring to a variation coefficient value supplied from the outside and a gamma unit for mapping the second gamma reference voltage value to a data signal And a driving unit, The first gamma reference voltage value is a 2.5 gamma reference voltage value, Wherein the second gamma reference voltage value is any one of a 1.0 gamma reference voltage value, a 1.8 gamma reference voltage value, and a 2.2 gamma reference voltage value.

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