KR100445435B1 - Display device of organic electro luminescent and driving method there of - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent display and a driving method thereof, and more particularly, to an organic electroluminescent display that enables high gradation, large area, and high resolution by using a thin film transistor (TFT). An apparatus and a driving method thereof are provided. The organic light emitting display device as described above has a plurality of data lines for transmitting a data current representing an image signal, a plurality of first scan lines for transferring a selection signal, and are alternately formed with the first scan lines, and emit light. A plurality of second scan lines for transmitting signals, and a plurality of pixel circuits each formed in a plurality of pixels defined by the plurality of data lines and the plurality of first scan lines and the second scan lines. In the electroluminescent display device, the pixel circuit includes a first switching element for switching a data voltage applied to the data line in response to an n-th selection signal applied to the first scan line, and applied to the first scan line. a second switching element for applying a constant voltage to one terminal of the first capacitor in response to the n-1 < th > selection signal, and being applied to the first scan line; a third switching element for diode-connecting a first transistor in response to an n-1 th selection signal, and a first switching element supplied from the first transistor in response to an n th light emission signal (Emission [n]) applied to the second scan line; A fourth switching element for transmitting a current to the organic electroluminescent element, a first transistor for supplying current to the organic electroluminescent element in response to the data voltage applied through the first switching element, and applied from the first transistor An organic electroluminescent element for emitting light corresponding to the amount of current to be made; a first capacitor for applying a data voltage value whose threshold voltage is compensated by the coupling with the second capacitor to the gate of the first transistor; And a second capacitor that maintains the voltage between the gate and the source of the first transistor for a set frame time. Therefore, in the pixel circuit of the present invention, the same pixel current flows through the entire panel by compensating for the variation of the threshold voltage of the TFT, and thus an organic EL display device having a high gradation, a large area, and a high resolution can be realized. .

Description

Display device of organic electroluminescent and driving method there of}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent display and a driving method thereof. More particularly, the present invention relates to an organic electroluminescent display that enables high gradation, large area, and high resolution by using a thin film transistor (hereinafter, referred to as TFT). The present invention relates to a display device and a driving method thereof.

In general, an organic EL display device is a display device for electrically exciting a fluorescent organic compound to emit light, and is capable of representing an image by driving voltage or current driving N × M organic light emitting cells.

Hereinafter, an organic light emitting diode according to the related art will be described with reference to the accompanying drawings.

1 is a view for explaining the basic structure of a general organic electroluminescent device.

A general organic electroluminescent device has a structure of an anode (ITO), organic thin film layers, and a cathode (Metal), as shown in FIG.

In this case, the organic thin film layers formed between the anode and the cathode have a good balance between electrons and holes to improve the light emitting efficiency, such as an emitting layer (EML), an electron transport layer (ETL) and a hole transport layer (HTL). It has a multi-layer structure including), and also includes a separate electron injection layer (EIL) and a hole injection layer (HIL).

As such a method of driving the organic light emitting cell, there are a simple matrix method and an active matrix method using a thin film transistor (TFT).

The simple matrix method is to form the anode and the cathode to be orthogonal and to select and drive the cathode and anode lines, and the active driving method is to integrate a thin film transistor (TFT) and a capacitor in each pixel to maintain the voltage by the capacitor capacity It is a driving method.

2 is a conventional voltage write type active matrix pixel circuit for driving an organic EL element, and FIG. 3 is a drive timing diagram for the conventional voltage write type active matrix pixel circuit shown in FIG.

Here, FIG. 2 is a conventional active matrix and voltage write pixel circuit for driving an organic EL element using a TFT, which representatively shows one of N x M pixels.

Referring to FIG. 2, a current driving transistor Mb is connected to an organic light emitting diode (hereinafter referred to as “OLED”) to supply a current for emitting light. The amount of current of the current-driven transistor Mb is controlled by the data voltage applied through the switching transistor Ma. At this time, a capacitor C for maintaining the applied voltage for a predetermined period is connected between the source and the gate of the transistor Mb. The n-th select signal line Select [n] is connected to the gate of the transistor Ma, and the data line Data [m] is connected to the source side.

Referring to the operation of the pixel having such a structure, as shown in FIG. 3, when the transistor Ma is turned on by the selection signal Select [n] applied to the gate of the switching transistor Ma, data is transmitted through the data line. The voltage V _DATA is applied to the gate (node A) of the driving transistor Mb.

In response to the data voltage V _DATA applied to the gate, a current flows through the transistor Mb to the organic EL element OLED to emit light.

At this time, the current flowing through the organic EL device is as shown in Equation 1 below.

Where I _OLED is the current flowing through the organic EL device, V _GS is the voltage between the source and gate of transistor Mb, V _TH is the threshold voltage of transistor Mb, V _DATA is the data voltage, and β is transistor Mb. This value represents the electrical conductivity of.

As shown in Equation 1, according to the pixel circuit shown in Fig. 3, a current corresponding to the applied data voltage V _DATA is supplied to the organic EL element OLED, and the organic EL element corresponds to the supplied current. Will emit light. In this case, the applied data voltage V _DATA has a multi-level value in a predetermined range to express gray scale.

However, in the conventional pixel circuit as described above, there is a problem in that it is difficult to obtain a high gradation due to the deviation of the threshold voltage Vth of the TFT caused by the nonuniformity of the manufacturing process.

For example, when driving a TFT of a pixel at 3V, a voltage must be applied to the gate voltage of the TFT at intervals of 12 mV (= 3 V / 256) in order to express an 8-bit 256 gray level. When the variation in the threshold voltage of the TFT is more than 100 mV, it is difficult to express high gray.

In order to solve the above problem, a pixel circuit for compensating the threshold voltage of the TFT has been proposed. FIG. 4 illustrates an active matrix and voltage write pixel circuit for driving an organic EL device as an example of a conventionally proposed pixel structure.

Referring to FIG. 4, the current-driven transistor M1 supplies a current for emitting light to the organic EL element OLED through the transistor M4, and the current amount of the transistor M1 is applied through the switching transistor M2. It is controlled by the data voltage.

The transistor M3 and the capacitor C1 are used to compensate for the change in the threshold voltage of the transistor M1, and the compensated pixel current is framed by the capacitor C2 connected between the source and the gate of the transistor M1. Will be maintained for a while.

Referring to the operation of the pixel having such a structure, as shown in FIG. 5, the auto zero signal AZ [n] applied to the gate of the transistor M3 is turned low so that the transistor M3 is turned on and the transistor is turned on. When the auto zero bar signal AZB [n] applied to the gate of M4 becomes high and the transistor M4 is turned off, the threshold voltage of the driving transistor Ma is stored in the capacitor C2. (Autozero behavior).

When the auto zero signal becomes high again and the data voltage is applied, the data voltage of the form in which the threshold voltage is compensated by the ratio of the data voltage and the capacitors C1 and C2 is applied to the gate of the transistor M1 (data Write operation). At this time, the gate voltage of the transistor M1 is shown in equation (2).

When the auto zero bar signal AZB [n] becomes low, the current as shown in Equation 3 flows to the organic EL element OLED by the voltage value of Equation 2 to emit light.

Here, V _G is the gate voltage of transistor M1, V _DD is the pixel supply voltage, | V _TH | is the threshold voltage of transistor M1, and ΔVdata is the amount of change in the applied data voltage.

Where I _OLED is the current flowing through the organic EL element, V _GS is the voltage between the source and gate of transistor M1, ΔVdata is the amount of change in the applied data voltage, | VTH | is the threshold voltage of transistor M1, and β is It is a value indicating the electrical conductivity of the transistor Mb.

As shown in Equation 3, according to the pixel circuit shown in FIG. 4, the current I _OLED flowing through the organic EL element flows only in response to the data voltage applied to the data line irrespective of the threshold voltage of the transistor M1. That is, according to the pixel circuit described above, since the deviation of the threshold voltage of the current driving transistor M1 is compensated for, it is possible to implement a high gray organic EL display device.

However, in the pixel circuit as described above, three different control signals (select, AZ, and AZB) are required, so that the pixel circuit and its surrounding circuits become somewhat complicated. In addition, it is difficult to implement a large-area, high-resolution organic EL display device because auto-zero and data writing must be performed during one line time.

The present invention reduces the number of control signals in the existing pixel circuit to simplify the pixel circuit and its surrounding circuit, and increases the threshold voltage storage time (autozero time) and data writing time in order to solve the above problems. Another object is to provide a high resolution organic electroluminescent (EL) display device and a driving method thereof.

An organic electroluminescent display device according to an aspect of the present invention for achieving the above object includes a plurality of data lines for transmitting a data current representing an image signal, a plurality of first scan lines for transmitting a selection signal, It is formed alternately with the first scan line, and is formed in a plurality of second scan lines for transmitting a light emission signal, and in a plurality of pixels defined by the plurality of data lines and the plurality of first scan lines and second scan lines, respectively. An organic light emitting display device comprising a plurality of pixel circuits, wherein the pixel circuits are configured to switch a data voltage applied to the data line in response to an n-th selection signal applied to the first scan line. A constant voltage is applied to the switching element and one terminal of the first capacitor in response to the n−1 th selection signal applied to the first scan line. A second switching element, a third switching element for diode-connecting the first transistor in response to an n-th selection signal applied to the first scan line, and an n-th light emission signal applied to the second scan line (Emission [n A fourth switching element for transmitting a current supplied from the first transistor to the organic electroluminescent element in response to the "), and supplying a current to the organic electroluminescent element in response to the data voltage applied through the first switching element. The first transistor comprises: a first transistor; an organic electroluminescent element emitting light corresponding to an amount of current applied from the first transistor; and a data voltage value at which a threshold voltage is compensated by coupling with a second capacitor; Maintaining a voltage between a first capacitor and a gate and a source of the first transistor for a predetermined frame time. It is configured to include a second capacitor.

Preferably, the first switching element includes a second transistor having a control terminal connected to the nth first scan line, and a first terminal and a second terminal connected to one terminal of the data line and the second switching element, respectively. The second switching element may include a control terminal connected to the n−1 th scan line, a first terminal connected to a power supply voltage, and a second terminal connected to a second terminal of the first switching device. A third transistor, wherein the third switching element has a control terminal connected to the n−1 th first scan line, a first terminal connected to a gate of the first transistor, and a third terminal connected to a drain of the first transistor And a fourth transistor having two terminals connected thereto, wherein the fourth switching element has a control terminal connected to the nth second scan line and a first terminal connected to a drain of the first transistor. And a fifth transistor having a second terminal connected to the electroluminescent element.

Preferably, the first to fourth switching elements are composed of one of a switch or a transistor, and the transistor is composed of a single crystal silicon transistor (MOS) or a thin film transistor (TFT).

Preferably the first to fourth transistors are transistors of the same conductivity type.

Preferably, the second switching element has a control terminal connected to the n-1 th first scan line, a first terminal is connected to the n-1 th second scan line, and a second terminal is connected to one side of the first switching element. It consists of a 3rd transistor connected.

According to another feature of the present invention for achieving the object as described above is formed alternately with a plurality of data lines, a plurality of first scan line for transmitting a selection signal, and a plurality of first scan line And a matrix having a plurality of second scan lines for transmitting a light emission signal and a transistor formed in an area surrounded by the plurality of data lines and a plurality of first scan lines and a second scan line, respectively, for supplying current to the organic electroluminescent element. A method of driving an organic electroluminescent display device comprising a plurality of pixels of a type, comprising: a first step of storing a threshold voltage of a transistor in a capacitor in response to a selection signal from an n-th first scan line of the scan lines; A second step of applying a data voltage representing a signal to the plurality of data lines, for selecting the row of pixels A third step of sequentially applying a selection signal to the plurality of first scan lines; switching a data voltage applied to the data line in response to a selection signal from an nth first scan line of the first scan lines, whereby a threshold voltage And a fourth step of delivering a compensated data voltage to the gate of the transistor, and a fifth step of supplying current to the organic light emitting display device in the transistor in response to a light emission signal from the second scan line.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

1 is a view illustrating a general organic electroluminescent device.

2 is a conventional voltage write type active matrix pixel circuit for driving an organic EL device.

3 is a driving timing diagram for the conventional voltage write type active matrix pixel circuit shown in FIG.

FIG. 4 is a conventional voltage write type active matrix pixel circuit improving the pixel circuit of FIG.

5 is a driving timing diagram for the pixel circuit of FIG. 4.

6 illustrates an organic electroluminescent display device according to the present invention.

7 is a view for explaining the basic concept of the pixel circuit of the organic electroluminescent display according to the present invention.

8 is a diagram illustrating a pixel circuit of an organic light emitting display device according to a first embodiment of the present invention.

9 is a diagram illustrating a pixel circuit of an organic light emitting display device according to a second exemplary embodiment of the present invention.

FIG. 10 is a driving timing diagram for a pixel circuit of the organic electroluminescent display shown in FIGS. 8 and 9.

11 is a diagram illustrating a pixel circuit of an organic light emitting display device according to a third exemplary embodiment of the present invention.

12 is a diagram illustrating a pixel circuit of an organic light emitting display device according to a fourth exemplary embodiment of the present invention.

FIG. 13 is a driving timing diagram for a pixel circuit of the organic electroluminescent display shown in FIGS. 11 and 12.

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

6 is a view showing an organic EL display device according to the present invention.

As shown in FIG. 6, an organic EL display device according to an exemplary embodiment of the present invention includes an organic EL display panel 10, a data driver 30, and a scan driver 20. It includes.

The organic EL display panel 10 includes a plurality of data lines D1, D2, D3,..., Dy that transmit data voltages representing image signals, and a plurality of first scan lines S1 that transmit a selection signal. S2, S3, ..., Sz and a plurality of agents for alternately forming light in a direction parallel to the plurality of first scan lines S1, S2, S3, ..., Sz to transmit the light emission signal. 2 scan lines E1, E2, E3, ..., Ez, the plurality of data lines D1, D2, D3, ..., Dy and the plurality of first scan lines S1, S2, S3, ... And Sz and a pixel circuit 11 formed in each of a plurality of pixels surrounded by a plurality of second scan lines E1, E2, E3, ..., Ez.

The data driver 30 applies a data voltage representing an image signal to the plurality of data lines D1, D2, D3,..., And Dy, and the scan driver 20 applies the plurality of first scan lines S1,. The selection signal and the emission signal are sequentially applied to S2, S3 ...., Sz and the second scanning lines E1, E2, E3, ..., Ez, respectively.

Fig. 7 is a view for explaining the basic concept of the pixel circuit of the organic EL device according to the present invention.

As shown in Fig. 7, the basic concept of the pixel circuit used in the organic EL device according to the present invention is an organic EL element OLED, a thin film transistor M1, and a plurality of first to fourth switches S1 and S2. , S3 and S4 and first and second capacitors C1 and C2.

The organic EL element OLED is connected between the drain of the current driving thin film transistor M1 and the ground and emits light corresponding to the amount of applied current.

The thin film transistor M1 supplies a current to the organic EL element OLED in response to the data voltage data [m] applied through the first switch S1.

The first switch S1 switches the data voltage applied to the data line in response to the nth select signal Select [n] applied to the first scan line.

The second switch S2 applies a constant voltage to one terminal of the first capacitor C1 in response to the n−1 th select signal Select [n−1] applied to the first scan line.

The third switch S3 diode-connects the thin film transistor M1 in response to the n-1 th select signal Select [n-1] applied to the first scan line.

The fourth switch S4 transfers the current supplied from the thin film transistor M1 to the organic EL element OLED in response to the nth light emission signal Emission [n] applied to the second scan line.

The first capacitor C1 applies a data voltage having a threshold voltage compensated by the coupling with the second capacitor C2 to the gate of the thin film transistor M1.

The second capacitor C2 maintains the voltage between the gate and the source of the thin film transistor M1 for a set frame time.

According to the pixel circuit shown in Fig. 7, the current supply thin film transistor M1 is formed of a PMOS thin film transistor, but may be formed of an NMOS thin film transistor as described later.

Next, the operation of the pixel circuit according to the embodiment of the present invention shown in FIG.

The third switch S3 is turned on by the n-1 th select signal Select [n-1] applied to the control terminal, so that the driving thin film transistor M1 is in a diode connection state, and the fourth switch S4 is turned on. Is turned off by the n th light emission signal (Emission [n]), the threshold voltage of the thin film transistor M1 is stored in the capacitor C2.

When the n-th select signal becomes high again and the third switch S3 is turned off and the n-th select signal becomes low and the first switch S1 is turned on to apply a data voltage, the data voltage and the first voltage are applied. In addition, a data voltage having a threshold voltage compensated by the ratio of the second capacitors C1 and C2 is applied to the gate of the thin film transistor M1. In this case, the gate voltage of the thin film transistor M1 is expressed by Equation 2 as described above.

When the nth light emission signal becomes low, the current as shown in Equation 3 flows to the organic EL element OLED by the voltage value of Equation 2 to emit light.

As shown in Equation 3, according to the pixel circuit shown in FIG. 7, the current I _OLED flowing through the organic EL element OLED is a data voltage applied to the data line regardless of the threshold voltage of the thin film transistor M1. Only flows in response. In other words, according to the pixel circuit, since the deviation of the threshold voltage of the current driving thin film transistor M1 is compensated for, an organic EL display device having a high gray level can be implemented. In addition, since the threshold voltage of the thin film transistor M1 is stored for the n-1th line time and data is written for the nth line time, the pixel circuit and its surrounding circuit can be simplified as compared with the conventional threshold voltage compensation pixel circuit. In addition, approximately twice the autozero time and data write time can be obtained.

Fig. 8 is a diagram showing a pixel circuit of the organic EL display device according to the first embodiment of the present invention.

As shown in FIG. 8, the pixel circuit according to the first embodiment of the present invention has a current supply transistor M1 composed of a PMOS transistor similarly to the pixel circuit shown in FIG. The first to fourth switches S1, S2, S3, and S4 are composed of the second to fifth PMOS transistors M2, M3, M4, and M5, respectively.

9 is a diagram showing a pixel circuit of an organic EL display device according to a second embodiment of the present invention.

As shown in Fig. 9, the pixel circuit according to the second embodiment of the present invention has almost the same configuration as the pixel circuit shown in Fig. 8, but the source of the third transistor M3 is the n-1th light emitting signal line ( It is connected to emission [n-1]).

That is, as shown in FIG. 8, when the source of the third transistor M3 is connected to the power supply voltage VDD, when implementing a large area and high resolution EL display device, if the pixel supply voltage is not constant in all panels due to IR drop. It causes the uniformity of the panel to drop. However, as shown in FIG. 9, the aforementioned effects can be reduced by connecting the source of the transistor M3 to the n-1 < th >

FIG. 10 is a timing diagram for driving the pixel circuits shown in FIGS. 8 and 9. FIG.

Referring to FIG. 10, the threshold voltage of the current driving thin film transistor M1 of the pixel is stored in the second capacitor C2 through the first n−1 th select signal Select [n−1], and the n th th capacitor is stored. The data signal Data [m] is compensated by the selection signal Select [n] and applied to the gate of the thin film transistor M1, and the corresponding pixel is emitted through the n-th emission signal Emission [n].

That is, in more detail, the n-th select signal Select [n-1] applied to the control terminal of the fourth transistor M4 is turned low to turn on the fourth transistor M4. When the n-th light emission signal (Emission [n]) applied to the control terminal of the fifth transistor M5 becomes high and the fifth transistor M5 is turned off, the threshold voltage of the driving thin film transistor M1 becomes zero. 2 is stored in the capacitor (C2).

When the n-th select signal becomes high again and the fourth transistor M4 is turned off and the n-th select signal becomes low and the second transistor M2 is turned on, a data voltage is applied to the data voltage and the capacitor C1. The data voltage compensated by the ratio of C2 is applied to the gate of the driving thin film transistor M1. At this time, the gate voltage of the thin film transistor M1 is shown in Equation 2.

When the nth light emission signal becomes low, the fifth transistor M5 is turned on, and the current as shown in Equation 3 flows to the organic EL element OLED by the voltage value of Equation 2 to emit light.

As shown in Equation 3, according to the pixel circuits shown in FIGS. 8 and 9, the current I _OLED flowing in the organic EL element is only applied to the data voltage applied to the data line regardless of the threshold voltage of the thin film transistor M1. Flows correspondingly.

Fig. 11 is a diagram showing a pixel circuit of the organic EL display device according to the third embodiment of the present invention.

The pixel circuit according to the third embodiment of the present invention has a configuration substantially the same as that of the pixel circuit shown in Fig. 8, but the sixth to tenth transistors M6, M7, M8, M9, and M10 are composed of NMOS transistors. The difference is that the circuit shown in Fig. 8 is completely symmetrical.

Fig. 12 is a diagram showing a pixel circuit of the organic EL display device according to the fourth embodiment of the invention.

The pixel circuit according to the fourth embodiment of the present invention has substantially the same configuration as the pixel circuit shown in Fig. 9, but the sixth to tenth transistors M6, M7, M8, M9, and M10 are composed of NMOS transistors. The difference is that the circuit shown in Fig. 9 is completely symmetrical.

FIG. 13 is a timing diagram for driving the pixel circuits shown in FIG. 11 and FIG. The timing diagram is a form in which the timing diagram of FIG. 10 is inverted. The operation is the same as that of FIG.

The description of the operation of the pixel circuits shown in FIGS. 11 and 12 and the description of the timing diagrams shown in FIG. 13 are easy to be understood by those skilled in the art to which the present invention pertains. As it is known in the art, redundant description will be omitted below.

As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, A various other change and a deformation | transformation are possible.

As described above, according to the present invention, the pixel circuit and its surrounding circuit are simplified by reducing the number of control signal lines, and since the threshold voltage compensation and data writing are performed for twice the line time, a large area and high resolution active matrix voltage is achieved. There is an advantage that a writing type organic EL display device and a driving method can be implemented.

Claims (6)

A plurality of data lines for transmitting a data current representing an image signal, a plurality of first scan lines for transmitting a selection signal, and a plurality of second scan lines for alternating with the first scan lines and for transmitting a light emission signal And a plurality of pixel circuits each formed in a plurality of pixels defined by the plurality of data lines and the plurality of first scan lines and the second scan lines, the organic light emitting display device comprising: The pixel circuit, A first switching element for switching a data voltage applied to the data line in response to an n-th selection signal applied to the first scan line; A second switching element configured to apply a constant voltage to one terminal of the first capacitor in response to the n−1 th selection signal applied to the first scan line; A third switching element for diode-connecting a first transistor in response to an n−1 th selection signal applied to the first scan line; A fourth switching device for transferring a current supplied from the first transistor to the organic electroluminescent device in response to an n-th light emission signal [Emission [n] applied to the second scan line; A first transistor supplying a current to an organic electroluminescent element in response to the data voltage applied through the first switching element; An organic electroluminescent element emitting light corresponding to the amount of current applied from the first transistor; A first capacitor for applying a data voltage value whose threshold voltage is compensated by a coupling with a second capacitor to a gate of the first transistor; And a second capacitor which maintains the voltage between the gate and the source of the first transistor for a set frame time. According to claim 1, The first switching device includes a second transistor having a control terminal connected to the n-th first scan line, and a first terminal and a second terminal connected to one terminal of the data line and the second switching device, respectively. The second switching element is a third terminal is connected to the control terminal is connected to the n-th first scan line, the first terminal is connected to the power supply voltage, the second terminal is connected to the second terminal of the first switching element Consisting of transistors, The third switching device has a fourth control terminal connected to the n-th first scan line, a first terminal connected to a gate of the first transistor, and a second terminal connected to a drain of the first transistor. Consisting of transistors, The fourth switching device includes a fifth transistor having a control terminal connected to the n-th second scan line, a first terminal connected to a drain of the first transistor, and a second terminal connected to the electroluminescent device. Organic electroluminescent display. The method of claim 1, And the first to fourth switching elements comprise one of a switch or a transistor, and the transistor comprises a single crystal silicon transistor (MOS) or a thin film transistor (TFT). The method of claim 2, And the first to fourth transistors are transistors of the same conductivity type. The method of claim 2, The second switching element is a control terminal is connected to the n-1 th first scan line, a first terminal is connected to the n-1 th second scan line, the second terminal is connected to one side of the first switching element An organic light emitting display device comprising: a third transistor. A plurality of matrix lines each having a plurality of data lines, a plurality of scan lines intersecting the plurality of data lines, and a transistor formed in a region surrounded by the plurality of data lines and the plurality of scan lines, each having a transistor for supplying current to an organic electroluminescent element In the driving method of an organic electroluminescent display device comprising a pixel of, A first step of storing a threshold voltage of a transistor in a capacitor in response to a selection signal from an n-1th scan line of the scan lines; A second step of applying a data voltage representing an image signal to the plurality of data lines; A third step of sequentially applying a selection signal for selecting the row of pixels to the plurality of scan lines; A fourth step of switching a data voltage applied to the data line in response to a selection signal from an nth scan line of the scan lines to transfer a data voltage compensated with a threshold voltage to a gate of the transistor; And And a fifth step of supplying a current to the organic light emitting display device in the transistor.