KR20080059010A - Organic electroluminescense display and driving method thereof - Google Patents

Abstract

An OELD device and a driving method thereof are provided to reduce the number of components by driving plural pixels through selecting and driving transistors based on a time division scheme. An OELD(Organic ElectroLuminescense Display) device includes plural organic electroluminescence elements(24a,24b,24c), plural driving transistors, and a selecting transistor(21). The organic electroluminescence elements are formed at sections which are defined by data and gate lines. The driving transistors(22a,22b,22c) drive respective electroluminescense elements. The selecting transistor selects a data signal through the data lines, stores the selected data signal, and drives the driving transistors based on the stored data signal. The selecting transistor drives the plural driving transistors in parallel.

Description

Organic EL display device and driving method thereof {ORGANIC ELECTROLUMINESCENSE DISPLAY AND DRIVING METHOD THEREOF}

1 is a circuit diagram of an organic EL display device according to a first embodiment of the present invention.

2 is another circuit configuration diagram of an organic EL display device in the present invention.

Fig. 3 is a further circuit configuration diagram of the organic EL display device in the present invention.

4 is a general circuit diagram of a conventional organic EL display device.

<Explanation of Signs of Major Parts of Drawings>

11 gate line 12 data line

13 power line 14 cathode line

21: first TFT 22, 22a, 22b, 22c: second TFT

23: storage capacity 24, 24a, 24b, 24c: OLED device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic EL display device, and more particularly, to an organic EL display device and a method of driving the same, which reduce the number of wirings to improve the yield and realize the aperture ratio.

4 is a typical circuit configuration diagram of a conventional organic EL display device. FIG. 4A is a diagram illustrating a circuit configuration in one pixel. 4B is a diagram showing a circuit configuration of a plurality of pixels in which three pixels of red, green, and blue are sequentially arranged.

The conventional organic EL display device includes a gate line 11, a data line 12, a power supply line 13, a cathode line 14, a first TFT 21, a second TFT 22, a storage capacitor 23, and the like. It consists of an organic light emitting display (OLED) element 24.

Here, the first TFT 21 constituting the first stage is for selecting and storing the data signal through the data line 12, and the second TFT 22 constituting the second stage is the OLED element 24. ) To drive. With respect to the configuration of the basic two-stage TFTs 21 and 22, a circuit has been developed in which an additional TFT is configured to compensate for the variation in the threshold voltage Vth of the second TFT 22 for driving.

This conventional organic EL display device is a kind of active matrix display device in which the data line 12 is crossed by the gate line 11, and the first TFT 21 and the second TFT 22 are connected to the OLED element 24. Are provided for each pixel so as to correspond to each other (for example, International Patent Publication No. WO 2004/049286 pamphlet).

In the conventional organic EL display device, as shown in FIG. 4, since the first TFT 21 and the second TFT 22 are provided for each pixel so as to correspond to the OLED element 24, the number of wirings is increased and the wiring defect is increased. This causes a decrease in the yield of the panel due to disconnection, and the opening ratio decreases as the number of wirings increases.

Accordingly, in order to solve the above problems, the present invention is to provide an organic EL display device and a driving method thereof which reduce the number of wirings to improve the yield and realize the improvement of the aperture ratio.

The organic EL display device according to the embodiment of the present invention for achieving the above technical problem is a plurality of organic EL elements installed in the region defined by the data line and the gate line, and the organic EL element is installed one to one in the organic EL device A driving transistor for driving an EL element, and a selection transistor for driving the driving transistor by selecting and holding a data signal through the data line, wherein the selection transistor is configured to drive a plurality of driving transistors in parallel. Characterized in that configured.

Each of the driving transistors driven by the selection transistors is supplied with power through respective power lines alternated sequentially to time-divisionally drive corresponding organic EL elements.

An organic EL display device according to another embodiment of the present invention is a selection for outputting a plurality of organic EL elements provided in a region defined by a data line and a gate line, and a data signal supplied to the data line according to the driving of the gate line. And a plurality of driving transistors for time-divisionally driving the respective organic EL elements in accordance with the data signal via the selection transistor.

In the organic EL display device, power is supplied to each of the driving transistors through respective power lines alternated sequentially.

Each driving transistor driven by the selection transistor in the organic EL display device has a stacked structure.

In the organic EL display device, the pixels driven by the respective driving transistors have a stacked structure.

The organic EL display device further comprises one storage capacitor for driving each of the driving transistors while maintaining the difference voltage between the data signal and the power supply via the selection transistor.

In the organic EL display device, each of the organic EL elements is formed to be connected to each of the driving transistors and to be connected to a cathode line or each of the power lines.

A method of driving an organic EL display device according to an exemplary embodiment of the present invention includes a plurality of organic EL elements installed in a region defined by crossing a data line and a gate line, and one to one organic EL elements installed one by one to drive the organic EL elements. And driving a selection transistor connected to the gate line, and maintaining the data signal through the data line according to the driving of the selection transistor to drive the driving transistor. The selection transistor is configured to drive a plurality of driving transistors in parallel.

In the driving method, each of the driving transistors driven by the selection transistors is supplied with power through respective power lines alternated sequentially to time-divisionally drive corresponding organic EL elements.

A method of driving an organic EL display device according to another embodiment of the present invention includes a plurality of organic EL elements provided in an area defined by crossing a data line and a gate line, and a plurality of driving transistors for driving each of the organic EL elements. And driving a selection transistor connected to the gate line to output a data signal supplied to the data line, and time-division driving each of the plurality of driving transistors in accordance with the data signal via the selection transistor. And driving each of the organic EL elements in accordance with time-division driving of each of the plurality of driving transistors.

The driving method is characterized in that it further comprises the step of supplying power through the respective power supply line alternately to each of the driving transistor.

In the driving method, each of the driving transistors is driven by one storage capacitor which holds the difference voltage between the data signal and the power supply via the selection transistor.

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

1 is a circuit diagram of an organic EL display device according to a first embodiment of the present invention.

Referring to FIG. 1, an organic EL display device according to a first exemplary embodiment of the present invention includes a gate line 11, a data line 12, a power line 13a, 13b, and 13c, a cathode line 14, and a first TFT. 21, second TFTs 22a, 22b, 22c, storage capacitor 23, and organic light emitting display (OLED) elements 24a, 24b, 24c. At this time, three pixels of red, green, and blue are collectively shown, and each pixel is represented by a, b, and c as reference numerals for individual components.

In the organic EL display device according to the first embodiment of the present invention, the second TFTs 22a, 22b, 22c, the OLED elements 24a, 24b, 24c, and the power supply lines 13a, 13b, 13c, which are driving transistors, respectively, are used. By using three of them, they are individualized to correspond to three pixels of red, green, and blue. On the other hand, one of the first TFTs 21 and the storage capacitors 23, which are the selection transistors, is used instead of three, and is used for three pixels of red, green, and blue.

More specifically, the second TFTs 22a, 22b, 22c and the power supply, which are individually installed to correspond to each pixel while simultaneously selecting three pixels of red, green, and blue by one first TFT 21 collectively, The individual OLED elements 24a, 24b, 24c are time-divisionally driven by alternately changing the red power supply, the green power supply, and the blue power supply using the lines 13a, 13b, and 13c.

By such time-division driving, one data line 12, one first TFT 21, and one storage capacitor 23 can be used for three pixels, so that the number of components and the number of wirings can be reduced. As a result, an organic EL display device in which the yield can be improved and the aperture ratio can be secured can also be realized.

As described above, the organic EL display device according to the first embodiment of the present invention can reduce the number of components and the number of wirings by time-divisionally driving a plurality of pixels by combining one selection transistor and a plurality of driving transistors. . As a result, an organic EL display device can be obtained which realizes a yield improvement and an aperture ratio improvement.

In addition, in the first embodiment of the present invention, the case where the power supply lines 13a, 13b, and 13c are separately provided for each of the red, green, and blue pixels has been described, but the present invention is not limited thereto. For example, the power lines 13a, 13b, and 13c are arranged in the periphery of the panel in units of 3 pixels so that the same effect can be achieved even if the three types of power supply, red power supply, green power supply, and blue power supply are changed alternately. You can get it.

In addition, the pixels corresponding to time division driving are not limited to every three pixels as in the first embodiment of the present invention described above, and the same effect can be obtained even if the configuration is applied to two or more pixels.

In addition, the power supply lines 13a, 13b, and 13c are equivalent even if they are replaced by the cathode wire 14. In addition, in the circuit diagram of the organic electroluminescence display of FIG. 1, since the connection of OLED element 24a, 24b, 24c is an example, it can also be set as another connection method.

2 is another circuit diagram of the organic EL display device in the present invention. For example, as shown in FIG. 2, the OLED elements 24a, 24b, and 24c are connected between the second TFTs 22a, 22b, and 22c and the respective power supply lines 13a, 13b, and 13c, respectively. The same effects as in the first embodiment of the present invention described above can be obtained.

In addition, although the case of time-divisionally driving the individual OLED elements 24a, 24b, and 24c was demonstrated about the 1st Example of this invention mentioned above, the organic electroluminescence display of this invention is not limited to this. By simultaneously driving the three OLED elements 24a, 24b, and 24c at the same level of voltage, the same effect as in the first embodiment of the present invention can be obtained, and then gray level monochrome display is possible.

In addition, the first embodiment of the present invention described above shows a case in which the RGB three pixels are arranged adjacent to each other on the same plane as shown in Figs. 1 and 2, but the organic EL display device of the present invention is the same. It is not limited. It is also possible to laminate | stack and structure each pixel. 3 is a further circuit configuration diagram of the organic EL display device of the present invention. For example, even when each pixel is stacked structured as shown in FIG. 3, the same effects as in the first embodiment of the present invention described based on the configuration of FIG. 1 can be obtained.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention It will be apparent to those skilled in the art.

The organic EL display device and the driving method thereof according to the embodiment of the present invention as described above are made to combine the selection transistor and the storage capacitor for a plurality of pixels, it is possible to reduce the number of wiring to improve the yield and aperture ratio. .

Claims (13)

A plurality of organic EL elements provided in regions defined by data lines and gate lines; A driving transistor provided one to one in the organic EL element to drive the organic EL element; And a selection transistor configured to select and hold a data signal through the data line to drive the driving transistor. And said selection transistor is configured to drive a plurality of driving transistors in parallel. The method of claim 1, And each of the driving transistors driven by the selection transistors is supplied with power through respective power lines alternated sequentially to time-divisionally drive corresponding organic EL elements. A plurality of organic EL elements provided in regions defined by data lines and gate lines; A selection transistor for outputting a data signal supplied to the data line according to the driving of the gate line; And a plurality of driving transistors for time-divisionally driving each organic EL element in accordance with the data signal via the selection transistor. The method of claim 3, wherein And each of the driving transistors is supplied with power through separate power lines alternately arranged. The method according to any one of claims 1 to 4, And each of the driving transistors driven by the selection transistor has a stacked structure. The method according to any one of claims 1 to 4, And the pixels driven by the respective driving transistors have a stacked structure. The method according to claim 2 or 4, And one storage capacitor for driving each of said driving transistors while maintaining the difference voltage between said data signal and said power source via said selection transistor. The method of claim 2 or 3, And each of the organic EL elements is connected to each of the driving transistors and is connected to a cathode ray or each of the power lines. A plurality of organic EL elements provided in an area defined by crossing the data line and the gate line, and a driving transistor provided in the organic EL element one-to-one and driving the organic EL element, Driving a selection transistor connected to the gate line; And driving the driving transistor by holding the data signal through the data line according to the driving of the selection transistor. And the selection transistor is configured to drive a plurality of driving transistors in parallel. The method of claim 9, Wherein each of the driving transistors driven by the selection transistors is supplied with power through respective power lines alternately alternately to time-divisionally drive corresponding organic EL elements. A plurality of organic EL elements provided in an area defined by crossing the data line and the gate line, and a plurality of driving transistors for driving each of the organic EL elements, Outputting a data signal supplied to the data line by driving a selection transistor connected to the gate line; Time-divisionally driving each of the plurality of driving transistors according to the data signal via the selection transistor; And driving each of the organic EL elements in accordance with time-division driving of each of the plurality of driving transistors. The method of claim 11, And supplying power through respective power lines alternately alternately provided to the respective driving transistors. The method according to claim 10 or 12, Wherein each of the driving transistors is driven by one storage capacitor which holds the difference voltage between the data signal and the power supply via the selection transistor.

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