KR20190078316A - Organic Light Emitting Display Device and Method for Driving the Same - Google Patents

Abstract

The present invention relates to an organic light emitting display device, which solves a problem of recognizing a measurement area of a panel recognized by the luminance difference from a non-measurement area when measuring an impedance of an organic light emitting diode to evaluate a deterioration level of an organic light emitting display device in a deterioration compensating method of the organic light emitting display device, and a driving method thereof. According to the present invention, the organic light emitting display device comprises: a display panel having a plurality of pixels including a driving transistor and an organic light emitting diode; a deterioration measuring unit for selecting any one of a plurality of first lines or any one of a plurality of second lines alternately disposed with the first lines in a sensing mode and sensing a source voltage of the driving transistor included in a measurement area for deterioration measurement; and an external compensation unit for turning on pixels on the first lines included in the measurement area of the display panel and driving pixels on the second lines included in the measurement area to have a black gray scale when the deterioration measuring unit senses any one of the first lines.

Description

[0001] The present invention relates to an organic light emitting display, and more particularly,

The present invention relates to an organic light emitting display and a driving method thereof. More particularly, the present invention relates to an organic light emitting diode (OLED) display device and a driving method thereof for improving a luminance difference between a measurement region and a non-measurement region of a panel when measuring an impedance of an organic light emitting diode.

Description of the Related Art [0002] A display device technology for displaying visual information as an image or an image in an information society has been developed. Among display devices, an organic light emitting display uses an organic light emitting diode that generates light by recombination of electrons and holes to display an image. The organic light emitting display device has a fast response speed and is capable of expressing low gradation according to the self light emission, and thus, it is attracting attention as a next generation display.

The organic light emitting display includes a display panel having data lines, scan lines, a plurality of pixels formed at intersections of data lines and scan lines, a gate driver for supplying scan signals to the scan lines, And a data driver for supplying data voltages to the data driver. Each of the pixels includes an organic light emitting diode, a driving transistor for controlling the amount of current supplied to the organic light emitting diode according to the voltage of the gate electrode, and a driving transistor for controlling the data voltage of the data line in response to the scanning signal of the scanning line. And a scan transistor for supplying a gate electrode of the driving transistor.

The threshold voltage of the driving transistor may vary from pixel to pixel due to a problem in manufacturing the organic light emitting display device or deterioration of the driving transistor due to long term driving. That is, when the same data voltage is applied to the pixels, the current supplied to the organic light emitting diode should be the same. However, even if the same data voltage is applied to the pixels due to the difference in threshold voltage of the driving transistor between the pixels, The current supplied may vary from pixel to pixel. In addition, the organic light emitting diode may also be deteriorated due to long-term driving. In this case, the brightness of the organic light emitting diode may vary from pixel to pixel. Accordingly, even if the same data voltage is applied to the pixels, the luminance at which the organic light emitting diode emits light may vary from pixel to pixel. To solve this problem, a compensation method for compensating for the threshold voltage of the driving transistor and deterioration of the organic light emitting diode is provided.

The threshold voltage of the driving transistor and the deterioration of the organic light emitting diode can be compensated by an external compensation method. The external compensation method supplies a predetermined data voltage to the pixel, senses the source voltage of the driving transistor through a predetermined sensing line according to a predetermined data voltage, and outputs the sensed voltage using an analog-digital converter Into digital data sensing data, and compensates the digital video data supplied to the pixels according to the sensing data.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a configuration diagram showing a display panel for performing deterioration measurement of a general organic light emitting display device. FIG.

As shown in Fig. 1 (a), the entire panel is divided into m x n regions, and each region is driven with constant data for sequentially measuring the deterioration amount. Then, the current flowing through the reference voltage (ELVDD) is measured through the current measuring circuit. By driving and measuring m x n regions in this manner, the drive current values for the respective regions are secured.

On the other hand, in the method of measuring the amount of deterioration, pixels included in an area where the deterioration is to be measured are turned on, and pixels included in other areas other than the deterioration amount are driven by black data to be turned off.

Therefore, as shown in Fig. 1 (b) to Fig. 1 (d), the conventional method of measuring the amount of deterioration is such that as the local area of the panel is sequentially selected and the deterioration amount is measured, There is a problem. That is, there is a problem that the region where the deterioration is measured due to the difference in brightness between the portion illuminated when the local region is driven and the region illuminated when the deteriorated region is not illuminated is recognized.

The present invention relates to a method of compensating degradation of an organic light emitting display, and more particularly, to a method of compensating degradation of an organic light emitting display, in which an organic light emitting diode A display device and a driving method thereof are provided.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description and more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

In order to solve such a problem, an OLED display device of the present invention includes a display panel having a plurality of pixels including a driving transistor and an organic light emitting diode, a display panel in which one of a plurality of first lines in the sensing mode, A deterioration measuring unit for selecting any one of the plurality of second lines arranged alternately with the first line of the driving transistor and sensing the source voltage of the driving transistor included in the measuring area for the deterioration measurement, And the pixels on the plurality of second lines included in the measurement area are lighted in the measurement area of the display panel when sensing any one of the plurality of first lines And an external compensation section for driving the pixel to have a black gradation.

The external compensation unit drives the pixels on the plurality of first lines included in the measurement area to have a black gradation when sensing the one of the plurality of first lines in the deterioration measuring unit, The pixels on the plurality of second lines not included in the second line are turned on.

The deterioration measuring unit may include a first deterioration measuring unit for sensing a source voltage of the driving transistor connected to the plurality of first lines included in the measurement region, And a second deterioration measuring unit for sensing a source voltage of the driving transistor connected to the second transistor.

The sensing unit may include a second power supply voltage supply unit for supplying a sensing power supply voltage, a second control switch for controlling the sensing power supply voltage to be provided to a drain electrode of the driving transistor in a sensing mode, An operational amplifier for sensing a sensing current flowing through the driving transistor and the organic light emitting diode at an input terminal, a feedback resistor for transmitting the sensing current to an output terminal of the operational amplifier, And an analog-to-digital converter for converting the sensing data into sensing data.

The degradation measuring unit may further include a first power supply voltage supply unit for providing a high potential power supply voltage and a first control switch for controlling the high potential power supply voltage to be provided to a drain electrode of the driving transistor in a display mode.

The deterioration measuring unit supplies a sensing power supply voltage lower than the high potential power supply voltage to a drain electrode of a driving transistor connected to the pixel to drive the driving transistor in a linear region.

The apparatus further includes an external compensation unit for calculating a deterioration compensation gain for correcting the digital video data transmitted from the system using the sensing data into compensated digital video data.

Also, the deterioration amount of the organic light emitting diode is measured for each measurement region in the display panel.

In addition, the measurement region includes two or more reference voltage lines.

Also, in the sensing mode, the plurality of first lines and the plurality of second lines are alternately selected in the sensing mode, and pixels corresponding to all the lines are lighted for one frame (one frame).

In order to solve such a problem, a method of driving an organic light emitting display according to the present invention includes the steps of: providing a high potential power supply voltage to a plurality of pixels in a display mode for displaying an image; Either one of the plurality of first lines or a plurality of second lines arranged alternately to the plurality of first lines is selected to sense the source voltage of the driving transistor included in the measuring region for the deterioration measurement The pixels on the plurality of first lines included in the measurement area are turned on and the pixels on the plurality of second lines included in the measurement area are turned on when the one of the plurality of first lines is sensed And is driven to have a black gradation.

The method further comprises the steps of: when any one of the plurality of first lines is sensed in the deterioration measuring unit, the pixels on the plurality of first lines not included in the measurement area are driven to have a black gradation; The pixels on the second plurality of lines are lighted.

The step of sensing the source voltage of the driving transistor may include sensing a source voltage of the driving transistor connected to the plurality of first lines included in the measurement region, And sensing the source voltage of the driving transistor connected on the second line.

The sensing of the source voltage of the driving transistor may include providing a sensing voltage to a drain electrode of the driving transistor, sensing a sensing current flowing through the driving transistor and the organic light emitting diode according to the sensing power supply voltage And converting sensing power supply voltages corresponding to the sensed current into sensed data.

The method further includes calculating a deterioration compensation gain for compensating the digital video data transmitted from the system using the sensing data into compensated digital video data.

In addition, sensing the source voltage of the driving transistor may provide a sensing power supply voltage lower than the high potential power supply voltage to a drain electrode of a driving transistor connected to the pixel to drive the driving transistor in a linear region.

In addition, the step of sensing the source voltage of the driving transistor measures the amount of deterioration of the organic light emitting diode for each region in the display panel.

Also, in the sensing mode, the plurality of first lines and the plurality of second lines are alternately selected in the display panel, and pixels corresponding to all the lines during one frame (one frame) are turned on.

According to one embodiment of the present invention, the organic light emitting display device and the driving method thereof according to the present invention improve the problem that the measurement region of the panel is detected by the non-measurement region and the luminance difference when measuring the impedance of the organic light emitting diode, The luminance difference between the measurement area and the non-measurement area can be eliminated.

1 is a configuration diagram showing a display panel for performing deterioration measurement of a general organic light emitting display device
2 is a block diagram showing a configuration of an organic light emitting diode display according to an embodiment of the present invention.
Fig. 3 is a circuit diagram showing in detail the configuration of the deterioration measuring unit shown in Fig. 2
4 is a circuit diagram schematically showing a driving circuit of an organic light emitting diode (OLED) in an organic light emitting display according to the present invention.
5 is a graph showing the source voltage of the driving TFTs of the organic light emitting display device of the present invention and the current flowing in the organic light emitting diode OLED
6 is a circuit diagram showing a configuration of an organic light emitting diode display according to an embodiment of the present invention.
FIG. 7 is a view showing an example of a panel structure for measuring the deterioration amount of an organic light emitting diode (OLED) in an even-numbered line in the organic light emitting display according to the present invention
8 is a view showing a panel structure for measuring the deterioration of an odd-numbered organic light emitting diode (OLED) in an organic light emitting display according to an embodiment of the present invention
9 is a waveform diagram showing the driving of the deterioration measuring unit of the organic light emitting display according to the present invention

The above and other objects, features, and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, which are not intended to limit the scope of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to denote the same or similar elements.

Hereinafter, an organic light emitting display according to a preferred embodiment of the present invention and a driving method thereof will be described in detail with reference to the drawings.

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

2, the OLED display of the present invention includes a display panel 100, a deterioration measurement unit 200, an external compensation unit 300, a data driver 500, and a gate driver 600 .

The display panel 100 includes a plurality of pixels, and the data lines D1 to Dm, m are positive integers of 2 or more, the reference voltage lines R1 to Rp, p are positive integers of 2 or more, (S1 to Sn, n is a positive integer of 2 or more), and sensing signal lines (SE1 to SEn). The data lines D1 to Dm and the reference voltage lines R1 to Rp may intersect the scan lines S1 to Sn and the sensing signal lines SE1 to SEn. The data lines D1 to Dm and the reference voltage lines R1 to Rp may be parallel to each other. The scan lines S1 to Sn and the signal sensing lines SE1 to SEn may be parallel to each other.

Each of the pixels includes one of the data lines D1 to Dm, one of the reference voltage lines R1 to Rp, one of the scan lines S1 to Sn, and one of the signal sensing lines SE1 to SEn Or the like. Each of the pixels may include an organic light emitting diode (OLED) and a plurality of transistors for supplying current to the organic light emitting diode.

The data driver 500 is connected to the data lines D1 to Dm in accordance with the compensated digital video data, the sensing digital video data, and the data timing control signal input from the external compensator 300 to supply the data voltages. The data driver 500 is connected to the reference voltage lines R1 to Rp and supplies the reference voltage ELVDD in the display mode.

The gate driver 600 is connected to the scan lines S1 to Sn according to a scan timing control signal input from the external compensator 300 to supply scan signals. The gate driver 600 sequentially supplies sensing control signals to the sensing signal lines SE1 to SEn in the sensing mode.

The sensing mode supplies sensing data voltages according to sensing digital video data to the pixels, thereby sensing the threshold voltages of the driving transistors of the pixels through reference voltage lines (R1 to Rp) connected to the respective pixels. In the sensing mode, the source voltage of the driving transistor is sensed to compensate for the electron mobility of the driving transistor of each pixel or the deterioration of the organic light emitting diode (OLED) of each pixel.

The deterioration measuring unit 200 separates the reference voltage lines R1 to Rp into an even-numbered line and an odd-numbered line. The deterioration measuring unit 200 generates the reference voltage ELVDD in the display mode and alternately or sequentially selects the even-numbered line and the odd-numbered line to supply the reference voltage ELVDD. At this time, the alternate selection means that the reference voltage is supplied to all the lines of the even-numbered lines, and then the reference voltage is supplied to all the lines of the odd-numbered lines. That is, the reference voltage is first supplied to the even lines of 2, 4, 6, 8, ..., and the reference voltages are supplied to the odd number lines of 1, 3, 5, 7, In addition, sequential selection refers to sequentially supplying reference voltages to even-numbered lines, odd-numbered lines, even-numbered lines, and odd-numbered lines. That is, the reference voltage is supplied in the order of 1, 2, 3, 4, 5, 6, 7, 8, ....

The deterioration measuring unit 200 may generate driving voltages necessary for driving the organic light emitting display according to the present invention in addition to the reference voltage ELVDD and supply the driving voltages to necessary configurations.

The deterioration measuring unit 200 estimates the deterioration amount of the organic light emitting diode OLED by sensing the source voltage of the driving TFT by alternately or sequentially selecting the even and odd lines in the sensing mode. The deterioration measuring unit 200 converts the source voltage of the sensed transistor into digital data sensing data SD. The converted sensing data SD is transmitted to the external compensation unit 300.

At this time, the sensing for estimating the deterioration amount is performed for each of a plurality of measurement areas on the display panel 100. The plurality of measurement areas are divided into a plurality of measurement areas mxn (where m is an integer equal to or greater than 2) and a length n (n is an integer equal to or greater than 2) on the basis of the sensing digital video data, ). Then, the deterioration measuring unit 200 separates the reference voltage lines R1 to Rp into an even-numbered line and an odd-numbered line, and then alternately or sequentially senses even-numbered lines and odd-numbered lines in the measurement area. One measurement region may include two or more reference voltage lines.

The pixels corresponding to the even lines (or the odd lines) among the pixels included in the measurement area 130 are turned on, and the pixels corresponding to the odd lines (or even lines) are displayed with black tones. In addition, the remaining area of the display panel 100 excluding the measurement area 130 is displayed in the opposite manner. That is, a pixel corresponding to an odd line (or an even line) is turned on, and a pixel corresponding to an even line (or an odd line) is displayed with a black tone. The even number lines (or the odd number lines) and the odd number lines (or the even number lines) are alternately or sequentially selected and the corresponding pixels are turned on. Accordingly, the display panel 100 exhibits an effect that the spatial average brightness is uniform in the measurement area and the non-measurement area as a whole, and the measurement area is not recognized.

The deterioration measuring unit 200 selects and senses the source voltage of the driving transistor of the pixels that are turned on in the measurement region.

The sensing mode may be performed before the power of the organic light emitting display device is turned off, or may be performed as soon as the power of the organic light emitting display device is turned on, or may be performed at a predetermined cycle with the power of the organic light emitting display device turned on. In addition, the measurement may be performed sequentially on the m x n regions at once, or may be divided into a plurality of regions each time the OLED display is turned on by a user turning on the product.

The deterioration measuring unit 200 separates the separation of the reference voltage lines R1 to Rp into an even-numbered line and an odd-numbered line, but this is not limitative in one embodiment. That is, two or more neighboring reference voltage lines can be grouped together and alternately separated from each other. At this time, the same number of reference voltage lines may be bundled (for example, 2: 1: 1: 2: 2: 2: 1: 1: ... etc). That is, the first and second reference voltage lines R1 and R2 are grouped into one, the third reference voltage line R3 is grouped into one, the fourth reference voltage line R4 is grouped into one, The seventh and eighth reference voltage lines R7 and R8 are grouped together and the ninth reference voltage line R9 is grouped together to form a tenth reference voltage line R10, Can be combined into one.

The deterioration measuring unit 200 selects all of the plurality of measurement regions (m x n) as an even-numbered line and an odd-numbered line, and senses the source voltage of the transistor. The degradation measuring unit 200 converts the sensing data SD to the external compensation unit 300. At this time, the sensing data SD transmitted to the external compensator 300 may be stored in the memory of the external compensator 300.

The external compensation unit 300 converts the digital video data into compensated digital video data using the sensing data SD sensed in the sensing mode. As a result, it is possible to compensate for the threshold voltage of the driving transistor of each pixel, the electron mobility of each driving transistor, and the deterioration of the organic light emitting diode. The external compensation unit 300 may include a memory for storing sensing data SD. The memory of the external compensation unit 300 may be a nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory). The external compensation unit 300 may be a timing controller.

3 is a circuit diagram showing the configuration of the deterioration measuring unit shown in Fig. 2 in detail.

3, the deterioration measuring unit 200 includes a first power supply voltage supply unit ELVDD1, a second power supply voltage supply unit ELVDD2, first and second control switches T1 and T2, (210), a feedback resistor (RF), and an ADC (220).

The first power-supply voltage supply unit ELVDD1 supplies the high-potential power-supply voltage ELVDD. The first power supply voltage supply unit ELVDD1 may be a line connected to a power management integrated circuit (PMIC) to transfer a high-potential power supply voltage generated by the power management integrated circuit. The high-potential power supply voltage ELVDD is the same voltage as the high-potential power supply voltage ELVDD for driving the display panel 100 in the display mode. Accordingly, the first power supply voltage supplying unit ELVDD1 can drive the plurality of driving transistors (driving TFT) and the organic light emitting diodes OLED in the display mode.

The second power supply voltage supply unit ELVDD2 alternately or sequentially supplies the sensing power supply voltage to the even-numbered lines and the odd-numbered lines. The sensing power supply voltage supplied may be less than the high potential supply voltage (ELVDD). The second power supply ELVDD2 supplies the sensing power supply voltage to the even or odd lines in which the pixels are lit in the measurement region 130. [ That is, if the reference voltage line in which the pixel is lit in the measurement region 130 is the even-numbered line, the second power-supply voltage supply unit ELVDD2 supplies the sensing power-supply voltage to the even-numbered line. If the reference voltage line in which the pixel is lit in the measurement region 130 is an odd line, the second power supply voltage supply unit ELVDD2 supplies the sensing power supply voltage to the odd numbered lines.

The pixels of even lines are turned on in the measurement area 130 of the display panel 100 and the pixels of the odd lines are displayed in the black gradation, the remaining area of the display panel 100 excluding the measurement area 130 is the odd- And the pixels on the even-numbered lines are displayed in black gradation.

The second power supply voltage ELVDD2 may be connected to a power management integrated circuit (PMIC) to generate the sensing power voltage using one of the driving power voltages generated by the power management integrated circuit. The sensing power supply voltage is a voltage smaller than the high potential supply voltage (ELVDD), and is a voltage that causes a plurality of driving transistors (Driving TFT) to operate in a linear region.

Hereinafter, the sensing power supply voltage of the second power supply voltage supply unit ELVDD2 for allowing a plurality of driving transistors (driving TFT) to operate in a linear region will be described in more detail with reference to the drawings.

FIG. 4 is a circuit diagram schematically illustrating a driving circuit of an organic light emitting diode (OLED) in the organic light emitting display according to the present invention. And a current flowing in the light emitting diode (OLED).

In the drawing, current-voltage (I-V) characteristic curves of a driving TFT and an organic light emitting diode (OLED) are shown. And also shows a method of determining the current according to the driving start point and the high-potential power supply voltage ELVDD on the current-voltage (I-V) characteristic curve.

In the display mode, the organic light emitting diode OLED is driven in the saturation region. In the saturation region, a certain amount of current flows through the organic light emitting diode (OLED) even when there is a change in the high-potential power supply voltage (ELVDD). In the sensing mode, the threshold voltage Vth of the driving TFT, the electron mobility of the driving transistor (driving TFT), or the deterioration characteristic of the organic light emitting diode OLED are driven in the linear region.

In order to drive the sensing mode in the linear region, a voltage smaller than the high potential power supply voltage ELVDD used for driving the organic light emitting diode OLED in the display mode is applied to the driving transistor (driving TFT) To the drain electrode of the transistor. The second power supply voltage supply unit ELVDD2 supplies a sensing power supply voltage having a voltage sufficiently lower than the high potential power supply voltage ELVDD in the sensing mode.

As shown in FIG. 5, when the threshold voltage Vth of the organic light emitting diode OLED is different in the linear region, the source voltage VTFT of the driving TFT is different.

That is, the first threshold voltage Vth0, which is the threshold voltage of the driving TFT connected to the first organic light emitting diode OLED1, is equal to the threshold of the driving TFT connected to the second organic light emitting diode OLED2 May be smaller than the magnitude of the second threshold voltage Vth1. In this case, the first source voltage VTFT0, which is the source voltage of the driving TFT connected to the first organic light emitting diode OLED1, is larger than the size of the driving TFT connected to the second organic light emitting diode OLED2. May be larger than the magnitude of the second source voltage VTFT1 which is the source voltage. In this case, the current I0 flowing through the first organic light emitting diode OLED1 is larger than the current I1 flowing through the second organic light emitting diode OLED2. It can also be seen that the degree of deterioration of the second organic light emitting diode OLED2 is significant and the current I1 flowing through the second organic light emitting diode OLED2 decreases.

As described above, when the organic light emitting diode OLED is deteriorated, the current-voltage (IV) characteristic curve moves from? To?, And the current flowing through the organic light emitting diode OLED decreases from I0 to I1. Thus, _{△ Vth = (I 0 - I} 1) R x may be from _TFT to calculate the organic light emitting diode (OLED), the amount of movement of the characteristic curve (△ Vth). The R _TFT means a TFT resistance in a linear region when a constant voltage (Vg) is applied to the gate of a driving transistor (Driving TFT).

The second power supply voltage ELVDD2 is supplied with a threshold voltage of a plurality of driving transistors (Driving TFT), a plurality of driving transistors (Driving TFTs) in a sensing mode using a shift amount DELTA Vth of an organic light emitting diode (OLED) characteristic curve, ) Or the degree of deterioration of a plurality of organic light emitting diodes (OLEDs).

The first control switch T1 connects the first power supply ELVDD1 and a plurality of driving transistors (Driving TFTs). The first control switch Tl is turned on by the first emission signal EL1 so that the first power supply voltage supply ELVDD1 can supply the high potential supply voltage ELVDD to the plurality of driving transistors DT. The first control switch Tl may be implemented as a P-type MOS transistor. However, the present invention is not limited to this, and the first control switch Tl may be implemented as a circuit element that can control turn-on and turn-off by a control signal.

The second control switch T2 connects an even-numbered reference voltage line and an odd-numbered reference voltage line of the plurality of driving transistors (Driving TFT) with the second power supply voltage supply ELVDD2. The second control switch T2 includes a control switch T2a for connecting the second power voltage supply ELVDD2 to the even reference voltage line and a control switch for connecting the second power voltage supply ELVDD2 to the even reference voltage line T2b).

The second control switch T2 includes a plurality of driving TFTs (Driving TFTs) that are turned on by the second emission signal EL2 and the second power supply voltage supply ELVDD2 is connected to the even reference voltage line or the odd reference voltage line, So that the sensing power supply voltage can be alternately or sequentially supplied. The second control switch T2 may be implemented by a P-type MOS transistor. However, the present invention is not limited to this, and the second control switch T2 may be implemented by a circuit element which can control the turn-on and turn-off by a control signal.

The operational amplifier 210 may be implemented as a circuit element close to an ideal op-amp (OP-AMP). The positive input terminal of the operational amplifier 210 is connected to the second power supply voltage supply ELVDD2, and the negative input terminal thereof is connected to the second control switch T2. The output terminal of the operational amplifier 210 is connected to an analog-to-digital converter (ADC) 220.

The operational amplifier 210 has a characteristic of keeping the voltages of the positive input terminal and the negative input terminal the same. Accordingly, the operational amplifier 210 can transmit the sensing power supply voltage supplied from the second power supply voltage supply ELVDD2 to the second control switch T2.

The feedback resistor (RF) is connected between the negative input terminal of the operational amplifier 210 and the output terminal of the operational amplifier 210. The current does not flow through the negative input terminal of the operational amplifier 210. Therefore, the negative input terminal and the output input terminal of the operational amplifier 210 must be connected in a line to receive the current and transmit the current to the ADC 220. A feedback resistor (RF) is disposed on the line connecting the negative input terminal and the output terminal of the operational amplifier 210.

The analog-to-digital converter (ADC) 220 converts the voltages sensed from the reference voltage lines (R 1 to Rp) into digital data sensing data (SD) in the sensing mode and transfers the voltages to the external compensation unit 300. The analog-to-digital converter (ADC) 220 converts voltages obtained by subtracting the voltage applied to the feedback resistor (RF) from the sensing power supply voltage generated by the second power supply voltage supply ELVDD2 through the operational amplifier 210, (SD). The analog-to-digital converter (ADC) 220 transmits the sensing data SD to an external compensation unit 300 that processes the deterioration compensation algorithm through an interface such as SPI or I2C.

The external compensation unit 300 calculates and compensates the deterioration compensation gain for compensating the digital video data transmitted from the system 400 into the compensated digital video data by the sensing data SD transmitted from the deterioration measuring unit 200. The external compensation unit 300 transmits the sensing digital video data transmitted from the system 400 to the data driver 500 in the sensing mode to generate a sensing mode pattern on the display panel 100. In the sensing mode pattern, only the pixels corresponding to the even lines (or the odd lines) are lit in the measurement region 130, and the pixels corresponding to the odd lines (or even lines) are displayed in black tones. In the sensing mode pattern, only the pixels corresponding to the odd lines (or even lines) are lit in the remaining area of the display panel 100 excluding the measurement area 130, and the pixels corresponding to the even lines (or odd lines) ). The even-numbered lines (or odd-numbered lines) and odd-numbered lines (or even-numbered lines) are alternately or sequentially selected and the corresponding pixels are turned on.

The external compensation unit 300 generates control signals necessary for driving the organic light emitting display according to the present invention and transmits the control signals to the necessary structures in addition to the compensation of the digital video data and the generation of the pattern of the sensing mode in the display panel 100 .

The data driver 500 supplies the compensated digital video data from the external compensator 300 to the data lines D1 to Dm as data voltages.

The deterioration measuring unit 200, and the external compensation unit 300 may be mounted on the control printed circuit board. The control printed circuit board can be connected to the source printed circuit board by a flexible cable.

6 is a circuit diagram showing a configuration of an OLED display according to an embodiment of the present invention.

6, the OLED display of the present invention includes a display panel 100, first and second deterioration measurement units 200a and 200b, and an external compensation unit 300. As shown in FIG. Hereinafter, the case of the display mode is not described, but only the case of the sensing mode will be described. 6, the deterioration measuring unit 200 includes a first deterioration measuring unit 200a for sensing a source voltage of a transistor by supplying a sensing power voltage to odd lines of a reference voltage line, And a second deterioration measurement unit 200b for sensing the source voltage of the transistor by supplying the power supply voltage. However, this configuration is not limited to this embodiment. That is, one deterioration measuring unit 200 may select an even-numbered line and an odd-numbered line using a separate switching element, and sense the source voltage of the transistor.

The first deterioration measuring unit 200a estimates the deterioration amount of the organic light emitting diode OLED connected to the odd numbered lines 110 among the reference voltage lines R1 to Rp in the sensing mode. The first deterioration measuring unit 200a supplies the odd voltage ELVDD_ODD to the drain electrode of the driving TFT connected to the odd lines 110 through the second power supply voltage supply unit ELVDD2. Here, the odd voltage ELVDD_ODD may be smaller than the high potential power supply voltage ELVDD.

The second power supply ELVDD2 is connected to the negative input terminal of the first operational amplifier 210a included in the first deterioration measuring unit 200a. In general, since the operational amplifier has a characteristic of keeping the voltages of the positive input terminal and the negative input terminal the same, the positive input terminal voltage of the first operational amplifier 210a becomes the second power supply voltage which is the negative input terminal voltage.

Then, when the second control switch T2a is turned on by the second emission signal EL2, the second control switch T2a connected to the positive input terminal of the first operational amplifier 210a turns on the odd-numbered lines 110, The second odd-numbered power supply current I_ELVDD_ODD flows. At this time, the second odd-numbered power supply current I_ELVDD_ODD flows only in the pixels lit on the odd-numbered lines of the measurement area 130 by the sensing digital video data, and the second odd-numbered power supply current I_ELVDD_ODD does not flow in the remaining non- .

Accordingly, a sensing voltage obtained by subtracting the voltage (RF * I_ELVDD_ODD) applied to the feedback resistor RF from the sensing power supply voltage generated by the second power supply voltage supply ELVDD2 is applied to the output terminal of the first operational amplifier 210a. Accordingly, the sensing voltage is applied to the output terminal of the first operational amplifier 210a, which is proportional to the amount of current I_ELVDD_ODD flowing to the pixels that are turned on in the measurement region 130.

The analog-to-digital converter (ADC) 220 converts the sensing voltage applied to the output terminal of the first operational amplifier 210a into digital data sensing data SD and transfers the sensing voltage to the external compensation unit 300.

The second deterioration measuring unit 200b has a second power supply ELVDD2 connected to the negative input terminal of the second operational amplifier 210b. In general, since the operational amplifier has a characteristic of keeping the voltages of the positive input terminal and the negative input terminal the same, the positive input terminal voltage of the second operational amplifier 210b is the second power supply voltage ELVDD2 which is the negative input terminal voltage do.

When the second control switch T2b is turned on by the second emission signal EL2, the second control switch T2b connected to the positive input terminal of the second operational amplifier 210b is turned to the even lines 120 The second even-numbered power supply current I_ELVDD_EVEN flows. At this time, only the second even-numbered power supply current I_ELVDD_EVEN flows through the even-numbered lines in the measurement region 130 due to the sensing digital video data, and the second even-numbered power supply current I_ELVDD_EVEN does not flow in the remaining non- .

Thus, a sensing voltage obtained by subtracting the voltage (RF * I_ELVDD_EVEN) applied to the feedback resistor RF from the sensing power supply voltage generated by the second power supply voltage supply ELVDD2 is applied to the output terminal of the second operational amplifier 210b. Accordingly, the sensing voltage is applied to the output terminal of the second operational amplifier 210b, which is proportional to the amount of current I_ELVDD_ODD flowing to the pixels that are turned on in the measurement region 130.

The analog-to-digital converter (ADC) 220 converts the sensing voltage applied to the output terminal of the second operational amplifier 210b into digital data sensing data SD and transfers the sensing voltage to the external compensator 300.

At this time, the display panel 100 displays a plurality of measurement areas mxn (where m is an integer of 2 or more) and a longitudinal n (n is an integer of 2 or more) ). Then, the deterioration measuring unit 200 measures the amount of deterioration by dividing the reference voltage lines R1 to Rp into an even-numbered line and an odd-numbered line. One measurement region 130 may include two or more reference voltage lines.

In the measurement area 130, only the pixels corresponding to the even lines (or the odd lines) are illuminated, and the pixels corresponding to the odd lines (or even lines) are displayed in the black gradation. On the contrary, only the pixels corresponding to the odd lines (or even lines) are lit and the pixels corresponding to the even lines (or odd lines) are displayed in the black tones . The even number lines (or the odd number lines) and the odd number lines (or the even number lines) are alternately or sequentially selected and the corresponding pixels are turned on.

The first deterioration measuring unit 200a is turned on when a pixel corresponding to an odd line of the measurement region 130 is turned on through the second emission signal EL2 transmitted from the external compensation unit 300, The voltage is sensed. The second deterioration measuring unit 200b senses the source voltage of the transistor when the pixel corresponding to the even line of the measurement region 130 is turned on.

The external compensator 300 compensates the digital video data transmitted from the system 400 by using the sensing data SD transmitted from the first deterioration measuring unit 200a and the second deterioration measuring unit 200b, . And provides compensated digital video data to the data driver 500. The data driver 500 supplies the compensated digital video data to the data lines D1 to Dm as data voltages. As a result, it is possible to compensate for the threshold voltage of the driving transistor of each pixel, the electron mobility of each driving transistor, and the deterioration of the organic light emitting diode.

6, the configuration of the organic light emitting display device is constructed by the first deterioration measuring unit 200a and the second deterioration measuring unit 200b, respectively. However, this is only an example, and the present invention is not limited thereto But may be implemented in other structures. In addition, these circuits may be included in PM-IC (Power Management IC) or SD-IC (Source Driver IC) or may be composed of discrete discrete elements.

FIG. 7 is an embodiment showing a panel structure for measuring the deterioration of an organic light emitting diode (OLED) in an even-numbered line in the organic light emitting display according to the present invention. OLED) deterioration amount measurement.

7 and 8, the current measurement for estimating the amount of deterioration of the organic light emitting diode (OLED) according to the present invention is performed on the display panel 100 with the measurement regions 130a, 130b, 110) (120).

The entire area of the display panel 100 is divided by the sensing digital video data into a plurality of measurement regions (mxn pieces) 130a, 130b (where m is an integer of 2 or more) and a longitudinal n (n is an integer of 2 or more) ). The deterioration measuring unit 200 separates the reference voltage lines R1 to Rp of the display panel 100 into the even line 120 and the odd line 110 and then outputs the odd number line and the odd number line Alternately or sequentially. Two or more reference voltage lines may be included in one measurement area 130a and 130b.

Thereafter, the deterioration measuring unit 200 sequentially selects a plurality of measurement regions 130a and 130b and senses the deterioration amount. At this time, the deterioration measuring unit 200 selects all of the plurality of measurement regions 130a and 130b (m x n) as the even line 120 and the odd line 110, and senses the source voltage of the transistor.

Each of the plurality of measurement regions 130a and 130b is sequentially displayed on the display panel 100 by sensing digital video data having a predetermined gradation and pattern.

7, only the pixels corresponding to the even lines (1 to 9) 120 in the first measurement region 130a are turned on while the pixels corresponding to the odd lines 110 are black Are displayed in gray scale. On the contrary, only the pixels corresponding to the odd-numbered lines 110 are turned on and the pixels corresponding to the even-numbered lines 120 are displayed in the black gradation.

8, only the pixels corresponding to the odd-numbered lines 10 to 15 (110) in the second measurement region 130b are turned on and the pixels corresponding to the even-numbered lines 120 Are displayed in black gradation. In the remaining area of the display panel 100 except for the second measurement area 130b, only the pixels corresponding to the even lines 120 are turned on and the pixels corresponding to the odd lines 110 are displayed in black tones.

The even-numbered (or odd-numbered) and odd-numbered (or even-numbered) measurements are performed alternately or sequentially in succession to equalize the temporal luminance averages.

Therefore, the spatial average brightness of the display panel 100 as a whole becomes equal to the measurement areas 130a and 130b in the non-measurement area. This makes it possible to solve the problem that the measurement areas 130a and 130b of the display panel 100 are recognized as a difference between a non-measurement area and a luminance difference in the measurement of the impedance for measuring the deterioration of the organic light emitting diode.

The deterioration measuring unit 200 applies a sensing power voltage so that a driving transistor (driving TFT) provided in the measurement region 130 can operate in a linear region. The deterioration measuring unit 200 senses a current flowing through the second power supply voltage supply unit ELVDD2. And a measurement current value for each of the plurality of measurement regions 130 can be ensured.

Measurement is performed at the initial stage of shipping of the display panel 100 to ensure measurement current data for each display panel 100 and for the area within the display panel 100 before deterioration occurs in the organic light emitting diode OLED . Meanwhile, even when the user uses the organic light emitting display according to the present invention, the current is sensed while performing the sensing operation for each region of the display panel 100 even at the set time, for example, when the organic light emitting display is turned on. The degree of deterioration of the organic light emitting diode OLED can be calculated from the difference of the current value by comparing the measured current value with the measured current value secured at the initial stage of shipment of the display panel 100.

9 is a waveform diagram showing driving of a deterioration measuring unit of the organic light emitting display according to the present invention.

The organic light emitting display according to the present invention has a driving sensing mode and a display mode. Also, since the first and second control switches T1 and T2 formed in the deterioration measuring unit 200 are P-type MOS transistors, they are turned off when a signal of a high logic level is input to the gate electrode, And is turned on when a low logic level signal is input to the gate electrode.

In the sensing mode, the first emission signal EL1 maintains a high logic level state to turn off the first control switch T1. And the second emission signal EL2 maintains a low logic level to turn on the second control switch T2. Accordingly, in the sensing mode, the drain electrode of the driving TFT is connected to the second power supply voltage supply ELVDD2 to receive the sensing power voltage. At this time, the first emission signal EL1 and the second emission signal EL2 are control signals transmitted from the external compensation unit 300, and select a sensing mode and a display mode.

The data voltage Vdata is input in the sensing mode and the display mode while repeating one frame period (1 frame) and the blank interval (BP) on the data lines D1 to Dm.

The ADC which is the output data of the analog-digital converter (ADC) 220 is outputted only in the blank section BP of the sensing mode, and is not outputted in the one frame period (1 frame) of the sensing mode and the display mode.

In the sensing mode, the deterioration measuring unit 200 turns off the first control switch T1 and the second control switch T2. Accordingly, the deterioration measuring unit 200 can supply the sensing power supply voltage to the display panel 100 in the sensing mode. The display panel 100 lights up only the pixels corresponding to the even lines (or odd lines) of the measurement area 130 by one frame period (1 frame) by the digital video data and the pixels corresponding to the odd lines Are displayed in black gradation. On the contrary, only the pixels corresponding to the odd-numbered lines (or the even-numbered lines) are illuminated and the pixels corresponding to the even-numbered lines (or odd-numbered lines) are displayed as black gradations. The even-numbered lines (or odd-numbered lines) and odd-numbered lines (or even-numbered lines) are alternately or sequentially selected and the corresponding pixels are turned on.

The deterioration measuring unit 200 measures the current flowing through the second power supply voltage supplying unit ELVDD2 through the analog-digital converter (ADC) 220 in the blank interval BP after each one frame period (1 frame) .

In the organic light emitting display of the present invention, the sensing mode is ended and the display mode is proceeded after the measurement is completed.

The deterioration measuring unit 200 keeps the first light emitting signal EL1 at a low logic level in the display mode and turns on the first control switch T1. And the second emission signal EL2 maintains the high logic level to turn off the second control switch T2. Accordingly, in the display mode, the deterioration measuring unit 200 supplies the high potential power supply voltage ELVDD by connecting the first power voltage supply unit ELVDD1 with the transistor electrode of the driving TFT.

The OLED display and the driving method thereof according to the present invention have corresponding deterioration models for each display panel or each display panel. At this time, by performing the deterioration compensation while maintaining the average spatial luminance of the display panel 100 as a whole in the measurement areas 130a and 130b and the non-measurement area, the degradation of the measurement area and the non- The occurrence of the luminance difference can be eliminated.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, But the present invention is not limited thereto.

100: display panel 110: odd line
120: even line 130: measurement area
200: deterioration measuring section 210: operational amplifier
220: analog-to-digital converter (ADC) 300: external compensation unit
400: system 500: data driver
600: Gate driver
ELVDD1, ELVDD2: First and second power supply voltage supplies
Driving TFT: Driving transistor OLED: Organic light emitting diode
T1, T2: first and second control switches RF: feedback resistor

Claims (18)

A display panel including a plurality of pixels including a driving transistor and an organic light emitting diode;
The method comprising: selecting one of a plurality of first lines in a sensing mode or a plurality of second lines alternately arranged in a plurality of first lines, A deterioration measuring unit for sensing a voltage; And
Wherein when the deterioration measuring unit senses any one of the plurality of first lines, it turns on a pixel on the plurality of first lines included in the measurement area of the display panel, And the pixel on the second line includes an external compensation section for driving to have a black gradation
Organic light emitting display.
The method according to claim 1,
The external compensation unit
Wherein when the deterioration measuring unit senses any one of the plurality of first lines, the pixel on the plurality of first lines included in the measurement area is driven to have a black gradation, and the plurality of And the pixel on the second line is turned on.
The method according to claim 1,
The deterioration measuring unit
A first deterioration measuring unit for sensing a source voltage of the driving transistor connected to the plurality of first lines included in the measurement region,
And a second deterioration measuring unit for sensing a source voltage of the driving transistor connected to the plurality of second lines included in the measurement area.
The method according to claim 1,
The deterioration measuring unit
A second power supply voltage supply unit for providing a sensing power supply voltage,
A second control switch which is controlled so that the sensing power supply voltage is provided to a drain electrode of the driving transistor in a sensing mode,
An operational amplifier for sensing a sensing current flowing through the driving transistor and the organic light emitting diode at an input terminal according to the sensing power supply voltage,
A feedback resistor for transmitting the sensing current to an output terminal of the operational amplifier,
And an analog-to-digital converter for converting a voltage sensed at an output terminal of the operational amplifier into sensing data.
5. The method of claim 4,
The deterioration measuring unit
A first power supply voltage supply unit for supplying a high potential power supply voltage,
And a first control switch for controlling the high-potential power supply voltage to be provided to a drain electrode of the driving transistor in a display mode.
6. The method of claim 5,
Wherein the deterioration measuring unit supplies a sensing power supply voltage lower than the high potential power supply voltage to a drain electrode of a driving transistor connected to the pixel to drive the driving transistor in a linear region.
5. The method of claim 4,
And an external compensation unit for calculating a deterioration compensation gain for correcting the digital video data transmitted from the system using the sensing data into compensated digital video data
Organic light emitting display.
The method according to claim 1,
And measures an amount of deterioration of the organic light emitting diode in each measurement region in the display panel.
The method according to claim 1,
Wherein the measurement region includes at least two reference voltage lines.
The method according to claim 1,
The display panel
Wherein the plurality of first lines and the plurality of second lines are alternately selected in the sensing mode and pixels corresponding to all the lines are lit for one frame.
Providing a high potential power supply voltage to a plurality of pixels in a display mode for displaying an image;
Any one of a plurality of first lines or a plurality of second lines arranged alternately with the plurality of first lines may be selected in a sensing mode for measuring the deterioration of the pixels, Sensing a source voltage of a driving transistor included therein; And
The pixels on the plurality of first lines included in the measurement area are turned on when sensing any one of the plurality of first lines and the pixels on the plurality of second lines included in the measurement area are black gradated ≪ / RTI >
A method of driving an organic light emitting display device.
12. The method of claim 11,
A pixel on the plurality of first lines not included in the measurement area is driven to have a black gradation when sensing the one of the plurality of first lines in the deterioration measuring unit;
Wherein the plurality of pixels on the second line included in the measurement area are lighted.
12. The method of claim 11,
The step of sensing the source voltage of the driving transistor
Sensing a source voltage of the driving transistor connected to the plurality of first lines included in the measurement area,
And sensing a source voltage of the driving transistor connected to the plurality of second lines included in the measurement area.
12. The method of claim 11,
The step of sensing the source voltage of the driving transistor
Providing a sensing power supply voltage to a drain electrode of the driving transistor,
Sensing a sensing current flowing through the driving transistor and the organic light emitting diode according to the sensing power supply voltage,
And converting sensing power supply voltages corresponding to the sensed current into sensed data.
15. The method of claim 14,
And calculating a deterioration compensation gain for correcting the digital video data transmitted from the system to compensated digital video data using the sensing data.

16. The method of claim 15,
The step of sensing the source voltage of the driving transistor
Wherein a sensing power supply voltage lower than the high potential power supply voltage is applied to a drain electrode of a driving transistor connected to the pixel to drive the driving transistor in a linear region.
12. The method of claim 11,
The step of sensing the source voltage of the driving transistor
Wherein the amount of deterioration of the organic light emitting diode is measured for each region of the display panel.
12. The method of claim 11,
In the sensing mode, the plurality of first lines and the plurality of second lines are alternately selected in the display panel, and pixels corresponding to all the lines are lighted for one frame (one frame).

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