KR100659529B1 - Electroluminescene Display Pannel to possess multi-anode electrode - Google Patents

Abstract

The present invention relates to an organic light emitting display device, and more particularly, to provide an organic EL device configured in the organic light emitting display device having a plurality of anodes so as to be easily repaired and replaced when a failure occurs due to a short circuit between the anode and the cathode during operation. The present invention relates to an electroluminescent display device.

An organic light emitting display device comprising a plurality of data lines, a plurality of gate lines, and pixels respectively formed at intersections of the data lines and the gate lines, wherein the pixels are connected to the data lines. An organic EL device which emits light when a data signal and a gate signal are applied through a gate line is included. The organic EL device includes a plurality of anode electrodes and one cathode electrode for each pixel. The plurality of anode electrodes have the same area. Alternatively, the plurality of anode electrodes may have different areas.

Multi-anode, organic light emitting display device, organic EL device

Description

Organic electroluminescent display device having a plurality of anode electrodes {Electroluminescene Display Pannel to possess multi-anode electrode}

1 is a block diagram illustrating a general organic light emitting display device;

2 is a circuit diagram of a unit pixel in a conventional organic light emitting display device;

3 is a plan view of a unit pixel in a conventional organic light emitting display device;

4 is a view showing a short circuit between an anode and a cathode of a conventional organic light emitting display device;

5 is a circuit diagram of a unit pixel of an organic light emitting display device according to an embodiment of the present invention;

6 is a plan view of a unit pixel of an organic light emitting display device according to an embodiment of the present invention;

7 is a plan view illustrating a repair step of an anode electrode shorted from the unit pixel of FIG. 6;

8 is a plan view of a unit pixel of an organic light emitting display device according to another exemplary embodiment of the present invention.

Explanation of symbols on main parts of drawing

10: data driver 20: scan driver

30 unit pixel 40 EL panel

341: first anode 342: second anode

343: third anode 340: anode

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device having a plurality of anodes for easy repair and replacement when a failure occurs due to a short circuit between the anode and the cathode during operation of the organic EL device. .

An organic EL device is a self-light emitting device that emits a fluorescent material by recombination of electrons and holes, and the EL display using the same has a faster response speed than a passive light emitting device requiring a separate light source, such as a liquid crystal display device, and a DC driving voltage. This low and ultra-thin film makes it possible to be wall-mounted or portable.

As such a method of driving the organic EL light emitting cell, there are a simple matrix method and an active matrix method using a TFT. In the simple matrix method, the anode and the cathode are orthogonal and the line is selected and driven, whereas the active driving method is a driving method in which a TFT and a capacitor are connected to each ITO pixel electrode to maintain a voltage by capacitor capacitance.

1 is a schematic plan view of a typical active matrix organic light emitting display device.

Reference numeral 10 denotes a data driver, 20 a scan driver, 30 a pixel, and 40 an EL panel.

The EL panel 40 includes a data driver 10, a scan driver 20, and a pixel 30, and the dual data driver 10 transmits an image signal through data lines D1, D2, D3 ... Dz. Outputs a data voltage, and the scan driver 20 sequentially outputs the gate signals through the gate lines S1, S2, S3, S4 ..... Sy, and the unit pixels 30 are R, G And any one of the R, G, and B unit pixels in a pixel including B.

As shown in the drawing, the EL panel 40 is branched from the data driver 10 to transmit a plurality of data lines D1, D2, D3, ..., Dz for transmitting image signals and gate signals. The gate lines S1, S2, S3, ..., Sy are arranged to cross each other, and the pixel circuit 30 is formed at each intersection point of the gate line and the data line.

FIG. 2 is a detailed circuit diagram illustrating a unit pixel circuit of FIG. 1.

Reference numeral Data is a data line to which a pixel signal is transmitted, Scan is a gate line to which a gate signal is applied, M1 is a first thin film transistor, Cst is a capacitor, M2 is a second thin film transistor, and OLED is an organic EL light emitting device.

The data line Data transmits an image signal, the gate line Scan transmits a gate signal, and the first thin film transistor M1 transmits data to the capacitor Cst according to the gate signal of the gate line Scan. Transfer, and the capacitor Cst stores the applied data. The second thin film transistor M2 drives the organic EL light emitting diode OLED.

As shown in the drawing, the organic EL element OLED is connected to the second thin film transistor M2 to receive a current for emitting light. The source of the second thin film transistor M2 is connected to the power line Vdd, and the gate thereof is connected to the drain of the first thin film transistor M1. The capacitor Cst is connected to the gate of the second thin film transistor M2 and the power line VDD, and the first thin film transistor M1 is connected to the gate of the gate line Scan, and the data is connected to the source. ) Is connected.

Referring to the operation of the pixel circuit having the above configuration in detail, when the first thin film transistor M1 is turned on by the gate signal Scan applied to the gate of the first thin film transistor M1, the data line Data Through the data signal is applied to the gate of the second thin film transistor M2. In addition, a current flows through the second thin film transistor M2 through the second thin film transistor M2 to emit light in response to the data signal applied to the gate.

At this time, the voltage Vgs between the source and the gate of the second thin film transistor M2 becomes a difference between the voltage of the power line VDD and the data voltage transmitted through the first thin film transistor M1 and the second thin film transistor M2. ) Outputs a current corresponding to the square of the difference between the source-gate voltage and the threshold voltage Vth of the transistor to the organic EL element OLED. This is expressed as an equation.

Where I _OLED is the current flowing through the organic EL device, Vgs is the voltage between the source and the gate of the second thin film transistor M2, Vth is the threshold voltage of the second thin film transistor M2, Vdata is the data voltage, and β is a constant. Indicates a value.

As shown in Equation 1, in the circuit of the unit pixel shown in Fig. 2, a current corresponding to the data signal is supplied to the organic EL element OLED, and the organic EL element OLED emits light corresponding to the supplied current. do.

The planar structure of the unit pixel of the conventional organic light emitting display device having the circuit configuration as described above is as shown in FIG.

3 is a plan view of one unit pixel of a conventional organic light emitting display device.

Referring to FIG. 3, a conventional unit pixel includes a gate line 32 arranged in one direction, a data line 31 arranged in a direction crossing the gate line 32, and an intersection with the gate line 32. And a power supply line 37 arranged parallel to the data line 31. In addition, the switching transistor 33 is connected to the gate line 32 and the data line 31, respectively. The capacitor is connected to one of the source / drain electrodes 34 of the switching transistor 33 and the power supply line 37 and the lower electrode 35 connected through the contact hole to the upper side of the capacitor lower electrode 35. The upper electrode 36 is disposed. The driving transistor 39 includes an anode electrode a having a gate 38 connected to the capacitor lower electrode and one of the source / drain electrodes 40 connected via a via hole 41.

In the conventional unit pixel as described above, in the organic EL device OLED, an anode electrode a is formed on a substrate, an EL layer is formed on an upper surface of the anode electrode a, and a cathode electrode is formed on an upper surface of the EL layer. (b) is formed.

In addition, only the EL layer (refer to FIG. 4) exists between the anode electrode a and the cathode electrode b, and an insulating film exists around the anode electrode except for the via hole, so that the anode electrode a and the cathode electrode b are ) Is energized directly without passing through the EL layer.

However, the conventional organic EL device is common with one anode electrode for each unit pixel. Since the cathode is disposed, fine dust is sandwiched between the anode and the cathode layer during the process, or a short circuit defect occurs in which the anode and the cathode are in contact with each other and are energized due to a pattern defect and an external pressure of the lower layer. As shown.

4 is a cross-sectional view illustrating a short circuit between an anode and a cathode in a conventional organic light emitting display device.

Reference numeral a denotes an anode electrode, b a cathode electrode, and c is fine dust.

As shown, fine dust is present in the insulating film between the anode a and the cathode electrode b so that the anode electrode a and the cathode electrode b are contacted due to the fine dust c. As a result of the short circuit between the anode electrode a and the cathode electrode b, a cathode voltage is applied to the anode electrode a so that a defect representing black is generated instead of emitting a predetermined color according to a data signal. However, in the conventional pixel circuit, since only one anode electrode and one cathode electrode are disposed, there is a problem in that replacement and repair are not easy.

 Accordingly, an object of the present invention is to provide an organic light emitting display device having a plurality of anode electrodes, which is easy to use and repair in case of failure due to a short circuit between the anode and the cathode.

An organic light emitting display device comprising a plurality of data lines, a plurality of gate lines, and pixels respectively formed at intersections of the data lines and the gate lines, wherein the pixels are connected to the data lines. An organic EL device which emits light when a data signal and a gate signal are applied through a gate line is included. The organic EL device includes a plurality of anode electrodes and one cathode electrode for each pixel.

The plurality of anode electrodes have the same area.

Alternatively, the plurality of anode electrodes may have different areas.

Alternatively, an organic light emitting display device comprising a plurality of data lines, a plurality of gate lines, and pixels respectively formed at intersections of the data lines and the gate lines, wherein each pixel includes a plurality of anode electrodes and a common cathode electrode. And a thin film transistor for driving the EL element according to a data signal transmitted through the data line, wherein the thin film transistor includes a semiconductor layer, a gate electrode, and a source / drain electrode. One of the source / drain electrodes is connected to the plurality of anode electrodes, respectively.

Here, the thin film transistor further includes a plurality of connection portions for connecting the drain of the driving transistor and the plurality of anode electrodes.

Alternatively, the connection portion may extend from at least the drain of the driving transistor so that its width is equal to or smaller than the width of the channel of the driving transistor.

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

5 is a circuit diagram showing a preferred embodiment of the present invention.

Reference numeral 341 denotes a first anode, 342 a second anode, and 343 a third anode.

As described above, when the gate signal is applied through the gate line, the first thin film transistor M1 is switched on to transfer the data signal transmitted through the data line Data to the capacitor Cst to store the data signal. Be sure to After the data charging period is completed, the data signal stored in the capacitor Cst is transferred to the second thin film transistor M2. Therefore, the second thin film transistor M2 transmits the driving current corresponding to the above Equation 1 to the organic EL element OLED to emit light corresponding to the applied data signal.

The organic EL element OLED includes a plurality of anode electrodes 341, 342 and 343 and one common cathode electrode. Therefore, when n anode electrodes 341, 342 and 343 are configured, the driving current is divided into n and transferred to each of the anodes 341, 342 and 343.

At this time, as described above, when one of the anode electrodes 341, 342 and 343, for example, the first anode electrode 341 and the cathode electrode is shorted or broken due to external pressure or fine dust, etc. The first anode electrode 341 is separated by blocking a portion connecting the anode electrode 341 and the driving transistor M2. Therefore, the driving currents delivered from the second thin film transistor M2 are divided into n−1 and delivered to the n−1 anodes 342 and 343.

As described above, when one of the anode electrodes is separated from the plurality of anode electrodes, the area of the anode electrode is reduced by that amount, but the current density is constant, so that the luminance of light is made constant. Therefore, the area of each anode electrode can be configured to have the same or different areas, it is preferable that the anode electrode is provided with two or more.

The structure of the plurality of anode electrodes as described above is as shown in FIG.

6 is a plan view illustrating a connection relationship between an anode electrode and a driving transistor in a plan view of a display device, and FIG. 7 is a plan view illustrating a repairing process of a shorted anode electrode.

As shown, the anode electrodes 341, 342 and 343 having the same area or different areas are provided with via holes 333a and 333b in the source / drain electrodes, for example, in the drain electrode 332. The source / drain electrode 332 is connected to the drain region (not shown) of the driving transistor 330 through a contact hole.

The drain electrode 332 is extended to be connected to the first to third anodes 341, 342, and 343 to connect to the first to third anodes 341, 342, and 343, respectively. First to third connecting portions 332a, 332b, and 332c are provided.

Therefore, as described above, for example, when the first anode 341 is short-circuited with the cathode 343, the first anode by scanning the laser to the first connection portion 332a as shown in FIG. The 341 is separated from the drain electrode 332 to block the current inflow of the first anode electrode 341 so that the driving current is supplied to the second and third anode electrodes 342 and 343.

8 is a plan view showing another embodiment of a display device according to the present invention.

As shown in the drawing, the first to third connection parts 332a, 332b, and 332c have a width smaller than that of the source / drain electrode 332. That is, if the width of the source / drain electrodes 332 is W1 and the widths of the connection portions 332a, 332b, 332c are W2, the first to third connection portions 332a and 332b are satisfied so as to satisfy W1> W2. When the width is set to 332c, the corresponding anode electrode 340 may be separated by laser scanning of a small beam width.

In the above-described embodiment of the present invention, three anode electrodes are formed as an example. However, the present invention is not limited thereto, and the present invention is to form a plurality of anode electrodes and one common cathode electrode.

The detailed description of the invention has been described with reference to specific embodiments of the invention as examples, but the invention is not limited thereto, and one having ordinary skill in the art to which the invention pertains without departing from the concept of the invention. Modification or modification of the invention in various forms by the ruler is of course included in the concept of the present invention.

As described above, the organic light emitting display device according to the present invention includes at least a plurality of anode electrodes and one cathode electrode, and thus, when one of the plurality of anode electrodes is shorted or fails, By separating the and realizing a predetermined color by concentrating the drive current to the other anode electrode that operates normally, there is an effect that it is easy to replace and repair compared to the conventional.

Claims (6)

delete delete delete An organic light emitting display device comprising a plurality of data lines, a plurality of gate lines, and pixels respectively formed at intersections of the data lines and the gate lines. Each pixel comprises an EL element having a plurality of anode electrodes and a common cathode electrode; A thin film transistor for driving the EL element in accordance with a data signal transmitted through the data line; The thin film transistor includes a semiconductor layer, a gate electrode, and a source / drain electrode, and includes a plurality of connection portions for connecting one of the source / drain electrodes and the plurality of anode electrodes, respectively, of the source / drain electrodes. One is an organic light emitting display device, characterized in that connected to each of the plurality of anode electrodes. The organic light emitting display device of claim 4, wherein the thin film transistor further comprises a plurality of connection portions for connecting the drain of the driving transistor and the plurality of anode electrodes. The organic light emitting display device as claimed in claim 4, wherein the connection portion extends from a drain of the driving transistor so that a width thereof is equal to or smaller than a width of a channel of the driving transistor.

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