KR100732811B1 - Organic light emitting display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display device, comprising: a plurality of first and second lines formed on a substrate, a pad portion formed on a substrate, for receiving a signal, formed in a pixel area of the substrate, and a first line; A plurality of organic electroluminescent elements connected between the second line, a first driver connected between the pad part and the first line, a second driver connected between the pad part and the second line, and a second connected between the pad part and the organic electroluminescent element An organic electroluminescent element connected between the first first line and the first second line and between the first first line and the last second line, the first and second power supply lines comprising a first and a second power supply line. The lengths of the first power supply lines to the connected organic electroluminescent elements are formed equal. When the power supply voltage input through the pad unit is supplied to each organic light emitting diode in the pixel area through the power supply line, the voltage due to the difference in the length of the power supply line from the connection portion of the pad unit and the power supply line to each organic light emitting diode. The luminance is made uniform by minimizing the drop.

Description

Organic light emitting display device

1 is a plan view illustrating a conventional organic light emitting display device.

FIG. 2 is a detailed view of the power supply line shown in FIG. 1. FIG.

3 is a plan view illustrating an organic light emitting display device according to an exemplary embodiment of the present invention.

4 is a cross-sectional view for describing the organic light emitting display device illustrated in FIG. 3.

5 is a detailed view of the power supply line shown in FIG.

<Explanation of symbols for the main parts of the drawings>

10, 100: substrate 20, 120: pixel region

22, 122: scan line 24, 124: data line

26. 126: organic light emitting display device 30, 130: non-pixel region

32, 36, 132, 136: power supply lines 40, 140: pad part

42, 142: scan driver 44, 144: data driver

101: buffer layer 102: semiconductor layer

102a and 102b: source and drain regions 102c: channel region

103: gate insulating film 104: gate electrode

105: interlayer insulating film 106a and 106b: source and drain electrodes

107: planarization layer 108: anode electrode

109: pixel defining layer 110: organic thin film layer

111: cathode electrodes 132a, 136a: first power bus line

132b and 136b: second power bus line

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device which minimizes a decrease in luminance due to voltage drop.

Organic luminescence display devices are the next generation display devices with self-luminous characteristics.They are in terms of viewing angle, contrast, response speed, power consumption, etc., compared to liquid crystal display devices (LCDs). It has excellent characteristics at, and can be manufactured in light weight and thinness because it does not need backlight.

1 is a plan view illustrating a conventional organic light emitting display device. A scan line 22, a data line 24, and a scan line may be formed in a pixel area 20 of a substrate 10. An organic electroluminescent element 26 is formed between the line 22 and the data line 24 in a matrix manner to form a pixel, and the scan line 22 of the pixel region 20 is formed in the non-pixel region 30. And from the outside through the power supply lines 32 and 36 and the pad portion 40 for the operation of the scan line 22 and the data line 24 extending from the data line 24, the organic electroluminescent element 26. The scan driver 42 and the data driver 44 which process the supplied signals and supply them to the scan line 22 and the data line 24 are formed. A film-type flexible printed circuit (FPC) (not shown) is electrically connected to the pad portion 40 of the organic light emitting display device configured as described above, and signals (power supply voltages ELVDD and ELVSS) and data from the outside through the FPC. Etc.) is input.

When a signal is input to the power supply lines 32 and 36, the scan driver 42, and the data driver 44 through the pad part 40, the scan driver 42 and the data driver 44 receive the scan signal and the data signal. Supply to scan line 22 and data line 24, respectively. Therefore, the organic electroluminescent element 26 of the pixel selected by the scan signal emits light corresponding to the data signal.

However, in the conventional organic light emitting display device, since the pad part 40 provided with the power voltages ELVDD and ELVSS from the outside is connected to one side of the power supply lines 32 and 36 as shown in FIG. The distance from (A1 and B1) to each organic electroluminescent element 26 is different. Therefore, assuming that the current I and the cross-sectional area A are constant when the voltage V and the resistance R are expressed as in the following Equations 1 and 2, the power supply voltage input to the pad part 40. The resistance of the power supply lines 32 and 36 increases as the distance l from the connecting portions A1 and B1 through which ELVDD and ELVSS are transmitted to the power supply lines 32 and 36 from the organic electroluminescent element 26 is increased. Since the value R increases, a voltage V drop occurs as shown in Equation 3 below.

Therefore, the luminance drop is generated for each organic electroluminescent element 26 due to the voltage drop, resulting in an uneven image quality. Time difference occurs.

An object of the present invention is to provide an organic light emitting display device which can minimize the voltage drop.

An organic light emitting display device according to an aspect of the present invention for achieving the above object is a substrate, a plurality of first and second lines formed on the substrate, a pad unit formed on the substrate and receiving a signal A plurality of organic light emitting diodes formed in a pixel area of the substrate and connected between the first and second lines, a first driver connected between the pad and the first line, the pad and the second line A second driving part connected between the lines, first and second power supply lines connected between the pad part and the organic light emitting device, the first first line being connected to the pad part and the first power supply line; And an organic electroluminescent device connected between the first and second lines and an organic electroluminescent device connected between the first first line and the last second line. The length of the first power supply line is the same.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided to those skilled in the art to fully understand the present invention, and may be modified in various forms, and the scope of the present invention is limited to the embodiments described below. no.

3 is a plan view illustrating an organic light emitting display device according to an exemplary embodiment of the present invention.

In the pixel region 120 of the substrate 100, an organic light emitting diode constituting a pixel is connected between the scan line 122 and the data line 124 and the scan line 122 and the data line 124 in a matrix manner. 126 is formed, and in the non-pixel region 130, the scan line 122 and the data line 124 extending from the scan line 122 and the data line 124 of the pixel region 120, the organic light emitting diode A scan driver 142 for processing signals supplied from the outside through the power supply lines 132 and 136 and the pad unit 140 for the operation of 126 and supplying them to the scan line 122 and the data line 124; The data driver 144 is formed.

The organic light emitting diode 126 is composed of an anode electrode and a cathode electrode, and an organic thin film layer formed between the anode electrode and the cathode electrode, and when a predetermined voltage is applied to the anode electrode and the cathode electrode, holes and cathode injected through the anode electrode are applied. Electrons injected through the electrode recombine in the organic thin film layer, and emit light due to the energy difference generated in the process. The organic thin film layer may have a structure in which a hole transport layer, an organic light emitting layer, and an electron transport layer are stacked, or may further include a hole injection layer and an electron injection layer.

In the case of the passive matrix method, the organic light emitting diode 126 is connected between the scan line 122 and the data line 124 in a matrix manner, and in the case of the active matrix method, the scan line 122 is provided. And a thin film transistor (TFT) for controlling the operation of the organic light emitting diode 126 and a signal between the organic light emitting diode 126 and the data line 124. Capacitors are further included.

The scan driver 142 and the data driver 144 are formed on the substrate 100 of the non-pixel region 130 during the manufacturing of the organic light emitting diode 126, or manufactured as a separate integrated circuit semiconductor chip. Afterwards, the substrate 100 may be attached to the substrate 100 so as to be connected to the scan line 122 and the data line 124 by a chip on glass or a wire bonding method.

4 is a cross-sectional view for describing the organic light emitting display device 126 in more detail, and schematically illustrates an example configured in an active matrix method.

 A buffer layer 101 is formed on the substrate 100, and a semiconductor layer 102 providing an active layer is formed on the buffer layer 101. The semiconductor layer 102 provides source and drain regions 102a and 102b and channel region 102c of the thin film transistor. The gate insulating film 103 is formed on the entire upper surface including the semiconductor layer 102, and the gate electrode 104 is formed on the gate insulating film 103 on the semiconductor layer 102. An interlayer insulating film 105 is formed on the entire upper surface including the gate electrode 104, and the source and drain regions 102a and 102b of the semiconductor layer 102 are exposed on the interlayer insulating film 105 and the gate insulating film 103. The contact hole is formed so as to. On the interlayer insulating layer 105, source and drain electrodes 106a and 106b are formed to be connected to the source and drain regions 102a and 102b through contact holes, and the entire upper surface including the source and drain electrodes 106a and 106b. The planarization layer 107 is formed in this. Via holes are formed in the planarization layer 107 to expose the source or drain electrodes 106a or 106b, and anode electrodes 108 connected to the source or drain electrodes 106a or 106b through the via holes are formed on the planarization layer 107. Is formed. In addition, a pixel defining layer 109 for exposing the anode electrode 108 of the emission region is formed on the planarization layer 107, and the organic thin film layer 110 and the cathode electrode 111 are disposed on the exposed anode electrode 108. ) Is formed.

FIG. 5 is a plan view for describing in detail the power supply lines 132 and 136 provided with the power voltages ELVDD and ELVSS from the outside through the pad unit 140.

The power supply line 132 is formed on at least one side of the pixel area 120 and is distributed from the first power bus line 132a and the first power bus line 132a connected to the pad unit 140, and thus, the pixel area 120. And a plurality of second power bus lines 132b connected to the organic light emitting display device 126. At this time, the connection portion A2 of the power supply line 132 and the pad portion 140 is connected to the middle portion of the first power bus line 132a, that is, between the first scan line 122 and the first data line 124. The length of the power supply line 132 to the electroluminescent element 126 and the organic electroluminescent element 126 connected between the first scan line 122 and the last data line 124 is the same.

The power supply line 136 is formed on at least one side of the pixel region 120 and is connected to the first power bus line 136a and the first power bus line 136a connected to the pad unit 140, and the pixel region 120. And a second power bus line 136b formed to surround the other side or the pixel region 120. The cathode electrode 111 of the organic light emitting diode 126 is formed on the power supply line 136, and a power voltage ELVSS may be applied to the cathode electrode 111 through the power supply line 136. The connection part B2 of the power supply line 132 and the pad part 140 is formed asymmetrically with the power supply line 132, for example, the connection part of the first power bus line 132a and the pad part 140. It may be formed on one side of the first power bus line 136a adjacent to (A2).

In the above embodiment, it is preferable that the first power bus lines 132a and 136a be formed wider than the second power bus lines 132b and 136b so that the sheet resistance value is reduced. In addition, the distance from the pad portion 140 to the connection portions A2 and B2 and the length of the second power bus line 132b from the first power bus line 132a to each organic light emitting element 126 are also the shortest distances. It is preferred to be designed as. According to the above embodiment, the distance from the pad portion 140 to the connection portions A2 and B2 may be increased than in the conventional case, but the increase in power consumption is less than 1% and can be ignored.

A film-type FPC (not shown) is electrically connected to the pad unit 140 of the organic light emitting display device configured as described above, and signals (power voltages ELVDD and ELVSS, data, etc.) are input from the outside through the FPC. do. When signals are input to the power supply lines 132 and 136, the scan driver 142, and the data driver 144 through the pad unit 140, the scan driver 142 and the data driver 144 may receive the scan signals and the data signals. Supply to scan line 122 and data line 124, respectively. Accordingly, the organic light emitting diode 126 of the pixel selected by the scan signal emits light corresponding to the data signal.

According to the present invention, the power supply voltage ELVDD input through the pad unit 140 is transferred to the first power bus line 132a through the connection unit A2 and then each organic field through the second power bus line 132b. Distributed to the light emitting device 126, wherein the power transmission path from the connection portion A2 is longest, that is, between the first scan line 122 and the first data line 124, Since the length of the power supply line 132 to the organic light emitting element 126 connected between the 122 and the last data line 124 is the same length, each organic light emitting element 126 has the same power supply voltage ELVDD. Is approved.

In addition, the power supply voltage ELVSS provided through the pad unit 140 is transferred to the first power bus line 136a through the connection unit B2 and then through each of the organic light emitting diodes through the second power bus line 136b. 126. The cathode electrode 111 of the organic light emitting diode 126 is formed on the power supply line 136 formed to surround the pixel region 120, so that the first scan line 122 and the first data line are formed. The organic electroluminescent device 126 connected between the 124 and the organic light emitting device 126 connected between the first scan line 122 and the last data line 124 have the same length of power transmission path, so that each organic The same power supply voltage ELVSS is applied to the electroluminescent element 126.

Therefore, the luminance of the organic light emitting diode is determined by the amount of current (I _OLED ) flowing through the organic light emitting diode as shown in Equation 4 below. Luminance degradation can be minimized.

Here, V _GS is a voltage between a gate and a source of the driving transistor, V _th is a threshold voltage of the driving transistor, V _DATA is a data voltage and ρ is a constant.

As described above, the preferred embodiment of the present invention has been disclosed through the detailed description and the drawings. The terms are used only for the purpose of describing the present invention and are not intended to limit the scope of the present invention as defined in the meaning or claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, in the present invention, when the power supply voltage input through the pad unit is supplied to each organic electroluminescent element in the pixel region through the power supply line, power is supplied from the connecting portion of the pad unit and the power supply line to each organic electroluminescent element. Uniform luminance can be achieved by minimizing the voltage drop due to the difference in line lengths.

Claims (8)

Board, A plurality of first and second lines formed on the substrate, A pad unit formed on the substrate and configured to receive a signal; A plurality of organic light emitting diodes formed in the pixel area of the substrate and connected between the first line and the second line; A first driver connected between the pad part and the first line, A second driver connected between the pad part and the second line, First and second power supply lines connected between the pad part and the organic light emitting device, An organic light emitting element connected between the first first line and the first second line and an organic light emitting element connected between the first first line and the last second line from a connection portion of the pad part and the first power supply line The organic light emitting display device having the same length as that of the first power supply line. The display device of claim 1, wherein the first power supply line comprises: a first power bus line formed on at least one side of the pixel area and connected to the pad part; And a plurality of second power bus lines distributed from the first power bus line and connected to the organic light emitting elements in the pixel area. The organic light emitting display device of claim 2, wherein the first power bus line is wider than the second power bus line. The display device of claim 1, wherein the second power supply line comprises: a first power bus line formed on at least one side of the pixel area and connected to the pad part; And a second power bus line connected to the first power bus line and formed on at least another side of the pixel area. The organic light emitting display device of claim 4, wherein the first power bus line is wider than the second power bus line. The organic light emitting display device of claim 1, wherein one electrode of the organic light emitting element is formed on the second power supply line. The organic light emitting display device of claim 1, wherein the second power supply line is asymmetrical with the first power supply line. The organic light emitting display device of claim 1, wherein a power supply voltage is applied to the first power supply line, and a ground voltage is applied to the second power supply line.

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