CN100477333C - Organic electroluminescent element and pixel structure, pixel array and driving method thereof - Google Patents

Abstract

An organic electroluminescent device comprises a first organic thin film transistor, a second organic thin film transistor and at least one organic functional layer. The second organic thin film transistor and the first organic thin film transistor are arranged up and down, and the organic functional layer is clamped between the second organic thin film transistor and the first organic thin film transistor. And simultaneously, applying voltage to the first organic thin film transistor and the second organic thin film transistor to enable the two organic thin film transistors to generate potential difference, and further enabling electrons and the hollow holes to move to the organic functional layer and be combined in the organic functional layer to emit light. By integrating the organic electroluminescent device and the organic thin film transistor, the aperture ratio and the process reliability of the organic electroluminescent device are improved.

Description

Organic electroluminescence element, its pixel structure, pixel array and driving method

technical field

The present invention relates to a light-emitting device, and in particular to an organic electroluminescent device (OEL Device) and its pixel structure, pixel array and driving method.

Background technique

With the advancement of multimedia, the importance of displays as an interface between humans and computers is increasing day by day. Among them, flat panel displays (FPDs) with superior characteristics such as high image quality, good space utilization efficiency, low power consumption, and no radiation have gradually become the mainstream of the market.

The so-called flat panel displays include liquid crystal displays (Liquid Crystal Display, LCD), organic electroluminescence displays, and plasma displays (Plasma Display Panel, PDP), etc. Among them, the organic electroluminescence display has self-luminescence (Emissive), which can be divided into small molecule organic electroluminescence display (small molecule OLED, SM-OLED) and polymer organic electroluminescence display according to the molecular weight of the organic functional material. There are two types of displays (polymer light-emitting display, PLED). Organic electroluminescent displays have no viewing angle limitation, low manufacturing cost, high response speed (about a hundred times higher than that of liquid crystal), power saving, DC drive that can be used in portable machines, wide operating temperature range, and light weight and can be used anywhere. Miniaturization and thinning of hardware equipment, etc., meet the characteristic requirements of displays in the multimedia era. Therefore, organic electroluminescent displays have great potential for development and are expected to become novel flat panel displays of the next generation.

Organic electroluminescent displays can generally be classified into active organic electroluminescent displays and passive organic electroluminescent displays according to their driving methods. For active organic electroluminescent displays, thin film transistors (thin film transistors, TFTs) are currently used as switching elements for driving display elements. FIG. 1 is a circuit diagram of a conventional active organic electroluminescence display. Please refer to FIG. 1 , a conventional active organic electroluminescent display 100 usually configures two thin film transistors T1, T2 and a capacitor C in each pixel to drive the pixel electrode 106 to make the organic electroluminescent element (not shown) ) emit light. Wherein, the pixel electrode 106 (the anode of the organic electroluminescent element) is a transparent electrode, so the light emitted by the organic electroluminescent element can be emitted from the pixel electrode 106 to the outside of the display. The actual light-emitting area of the pixel in FIG. 1 is only equivalent to the area of the pixel electrode 106, and the area other than the pixel electrode 106 (the area where the thin film transistors T1, T2 and capacitor C are arranged) does not emit light. Therefore, the pixel aperture ratio of the organic electroluminescent display 100 is limited by the size of the thin film transistors T1 and T2 and the capacitor C. In order to increase the aperture ratio of the active organic electroluminescence display 100, the area of the pixel electrode 106 must be increased, but the reliability of the manufacturing process may be reduced accordingly.

In order to solve the above problems, a top-emitting active organic electroluminescent display is conventionally proposed. FIG. 2 is a schematic partial cross-sectional view of a conventional top-emission active organic electroluminescence display. Please refer to FIG. 2, when the anode 206 (that is, the pixel electrode) of the active organic electroluminescent display 200 is a general metal electrode, and the cathode 210 is a transparent electrode, the light emitted by the organic functional layer 208 can pass through the cathode. 210 and is emitted along the direction 212 shown in FIG. 2 . Since the active organic electroluminescent display 2 emits light from the top, the aperture ratio of the organic electroluminescent display 200 is not limited by the size of the switching element 204 .

However, using thin film transistors to drive organic electroluminescent devices may increase process uncertainties, resulting in reduced process reliability.

Contents of the invention

The object of the present invention is to provide an organic electroluminescent device and its pixel structure, pixel array and driving method, which can have better aperture ratio and process reliability.

The present invention proposes an organic electroluminescence element, which includes a first organic thin film transistor (Organic Thin Film Transistor, OTFT), a second organic thin film transistor and at least one organic functional layer. Wherein, the first organic thin film transistor has a first control terminal, a first input terminal, a first output terminal and a first channel, and the first channel is located between the first input terminal and the first output terminal. The second organic thin film transistor has a second control terminal, a second input terminal, a second output terminal and a second channel, and the second channel is located between the second input terminal and the second output terminal. The second organic thin film transistor and the first organic thin film transistor are arranged up and down, and the organic functional layer is sandwiched between the second organic thin film transistor and the first organic thin film transistor.

The present invention proposes a pixel structure of an organic electroluminescence element, which includes an above-mentioned organic electroluminescence element, a switch element and a charge storage element. Wherein, the second control terminal of the second organic thin film transistor is connected to the first output terminal of the first organic thin film transistor, and the first pulling terminal of the first organic thin film transistor is connected with the second organic thin film transistor through the organic functional layer. The second control terminal connection. The switch element has a third output terminal, a third input terminal and a third control terminal. Wherein, the third output terminal is connected to the first input terminal of the first organic thin film transistor. The charge storage element is connected to the first output end of the first organic thin film transistor and the second input end of the second organic thin film transistor.

The present invention proposes a pixel array of an organic electroluminescent device, which includes the above-mentioned pixel structure of the organic electroluminescent device, a first scanning line, a data line and a second scanning line. Wherein, the first scan line is connected to the third control end of the switch element, the data line is connected to the third input end of the switch element, and the second scan line is connected to the first control end of the first organic thin film transistor.

In an embodiment of the present invention, the switch element includes at least one thin film transistor, and the charge storage element includes at least one capacitor.

In one embodiment of the present invention, the organic functional layer is sandwiched between the first channel and the second channel, and in other embodiments, the organic functional layer can also be sandwiched between the first input terminal and the second input terminal. terminals, or sandwiched between the first output terminal and the second output terminal. The projection direction of the first channel is, for example, perpendicular to the projection direction of the second channel.

In an embodiment of the present invention, the first organic thin film transistor is a p-type organic thin film transistor, and the second organic thin film transistor is an n-type organic thin film transistor. Wherein the first input end is a source, the first output end is a drain, the second input end is a drain, and the second output end is a source.

In an embodiment of the present invention, the first organic thin film transistor is an n-type organic thin film transistor, and the second organic thin film transistor is a p-type organic thin film transistor. Wherein the first input end is a drain, the first output end is a source, the second input end is a source, and the second output end is a drain.

In an embodiment of the present invention, the first channel is, for example, disposed above the first control terminal, and the second channel is, for example, disposed below the second control terminal.

In an embodiment of the present invention, the organic electroluminescent device further includes a first insulating layer and a second insulating layer, which are respectively arranged between the first control terminal and the first channel, and the second control terminal and the first channel between the two channels. The first insulating layer is, for example, disposed between the first input end and the first output end, and the first channel is, for example, disposed on the first insulating layer. The second insulating layer is, for example, disposed between the second input end and the second output end, and the second channel is, for example, disposed under the second insulating layer.

In an embodiment of the present invention, the first input terminal and the first output terminal are, for example, disposed in the organic functional layer. The second input terminal and the second output terminal are also, for example, disposed in the organic functional layer.

In an embodiment of the present invention, the material of the organic functional layer is, for example, selected from at least one of high molecular organic materials and small molecular organic materials. The material of the first control terminal, the first input terminal, the first output terminal, the second control terminal, the second input terminal and the second output terminal is, for example, a conductive material or a conductive metal oxide, wherein the conductive metal oxide is, for example, selected At least one of indium tin oxide (ITO), aluminum zinc oxide (AZO), indium zinc oxide (IZO) and cadmium tin oxide (Cdsno), wherein the conductive material is, for example, selected from aluminum/lithium fluoride, At least one of aluminum, calcium, magnesium, indium, tin, manganese, chromium, copper, silver, gold and alloys thereof. The alloy containing magnesium is magnesium-silver alloy, magnesium-indium alloy, magnesium-tin alloy, magnesium-antimony alloy or magnesium-tellurium alloy. For example, the drain and source of an n-type organic thin film transistor are suitable to use conductive materials with low work function, and the drain and source of p-type organic thin film transistors are suitable to use conductive materials with high work function.

The present invention further proposes a driving method of the organic electroluminescent device, which is suitable for driving the above-mentioned pixel array of the organic electroluminescent device. In this method, two voltages are respectively inputted to turn on the switching element and the first organic thin film transistor, and the second organic thin film transistor is turned off, and then the data signal is input to store in the charge storage element. Then turn off the switching element, and change the voltage input to the first organic thin film transistor to turn on the second organic thin film transistor, and generate a potential difference between the first organic thin film transistor and the second organic thin film transistor to drive the organic thin film transistor. Excite light element.

The invention integrates the organic electroluminescence element and the organic thin film transistor, so the organic electroluminescence element with better aperture ratio can be manufactured and the reliability of the manufacturing process can be improved.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic circuit diagram of a part of a conventional active organic electroluminescence display.

FIG. 2 is a schematic partial cross-sectional view of a conventional top-emission active organic electroluminescence display.

FIG. 3 is a three-dimensional exploded view of an organic electroluminescence device according to a preferred embodiment of the present invention.

4A to 4C are schematic cross-sectional views of the first organic thin film transistor and the organic functional layer of the organic electroluminescence device according to a preferred embodiment of the present invention, respectively.

FIG. 5 is a schematic circuit diagram of a pixel array of an organic electroluminescent device according to a preferred embodiment of the present invention.

FIG. 6 is a waveform diagram of signals input into the first scan line and the second scan line shown in FIG. 5 .

100, 200: Active organic electroluminescent displays

106: pixel electrode

204: switching element

206: anode

208: Organic functional layer

210: Cathode

212: direction

300: Organic electroluminescence element

301: carrier

306a: first insulating layer

306b: second insulating layer

308a: first channel

308b: second channel

310: The first organic thin film transistor

312: The first control terminal

314a: first input terminal

314b: first output terminal

320: second organic thin film transistor

322: Second control terminal

324a: second input terminal

324b: Second steal end

330: Organic functional layer

800: Pixel array of organic electroluminescent elements

802: switching element

808: First scan line

810: Second scan line

812: data line

816: Charge storage element

820: Pixel structure

C: Capacitance

G: the third control terminal

I: the third input terminal

O: the third output terminal

T1, T2: thin film transistor

Detailed ways

The invention uses the gate electrode of the organic thin film transistor as the upper and lower electrodes of the organic electroluminescent element to increase the aperture ratio of the organic electroluminescent element. The following examples will be given to illustrate the present invention. It should be noted that the following examples are only used to illustrate the present invention, but not to limit the present invention. Those skilled in the art can slightly modify the following embodiments according to the spirit of the present invention, but they also fall within the scope of the present invention.

FIG. 3 is a three-dimensional exploded view of an organic electroluminescence device according to a preferred embodiment of the present invention. Referring to FIG. 3 , the organic electroluminescence device 300 includes a first organic thin film transistor 310 , a second organic thin film transistor 320 and at least one organic functional layer 330 . Wherein, the first organic thin film transistor 310 has a first control terminal 312, a first input terminal 314a, a first output terminal 314b and a first channel 308a, and the first channel 308a is located between the first input terminal 314a and the first channel 308a. Between one output terminal 314b. Between the first control terminal 312 and the first channel 308a, for example, a first insulating layer 306a is disposed, and the first channel 308a is, for example, located on the first insulating layer 306a.

The second organic thin film transistor 320 has a second control terminal 322, a second input terminal 324a, a second output terminal 324b and a second channel 308b, and the second channel 308b is located at the second input terminal 324a and the second output terminal Between the ends 324b, between the second control end 322 and the second channel 308b, for example, a second insulating layer 306b is disposed, and the second channel 308b is, for example, located under the second insulating layer 306b.

The projection direction of the first channel 308a of the first organic thin film transistor 310 is different from the projection direction of the second channel 308b of the second organic thin film transistor 320 by an angle, such as being vertical, and the second input of the second organic thin film transistor 320 The extension direction of the end 324a toward the second output end 324b is perpendicular to the extension direction of the first input end 314a of the first organic thin film transistor 310 toward the first output end 314b.

Please continue to refer to FIG. 3, the first control terminal 312 and the first input terminal 314a, the first output terminal 314b of the first organic thin film transistor 310 and the second control terminal 322 and the second input terminal 324a of the second organic thin film transistor 320, The material of the second output end 324b is, for example, conductive material or conductive metal oxide. In terms of conductive materials, it is preferably at least one selected from gold, aluminum, aluminum/lithium fluoride, calcium, magnesium, silver, copper, chromium, manganese, indium, tin and alloys thereof, wherein magnesium alloy, which is preferably magnesium-silver alloy, magnesium-indium alloy, magnesium-tin alloy, magnesium-antimony alloy or magnesium-tellurium alloy. As for the conductive metal oxide, it is preferably at least one selected from indium tin oxide, aluminum zinc oxide, indium zinc oxide and cadmium tin oxide.

The organic functional layer 330 is sandwiched between the first organic thin film transistor 310 and the second organic thin film transistor 320, and in this embodiment, the organic functional layer 330 is sandwiched between the first channel 308a and the second channel 308b, for example. Between, and the material of the organic functional layer 330 is, for example, selected from at least one of high molecular organic materials and small molecular organic materials. The organic functional layer 330 of the present invention can be composed of single-layer, double-layer, three-layer or even multi-layer organic material layers. The present invention does not limit the number of organic functional layers 330 , those skilled in the art can determine the number of organic functional layers 330 according to actual device and process requirements.

Please refer to FIG. 3 again, the first organic thin film transistor 310 is, for example, a p-type or n-type organic thin film transistor, and when the first organic thin film transistor 310 is a p-type organic thin film transistor, the second organic thin film transistor 320 is an n-type organic thin film transistor. transistor. The first channel 308 a is made of, for example, an organic material that can transport holes, and the second channel 308 b is, for example, made of an organic material that can transport electrons. Therefore, when holes are transmitted from the first input terminal 314a (source) to the first output terminal 314b (drain) through the first channel 308a, and electrons are transmitted from the second input terminal 324a (drain) to the first output terminal 308b through the second channel 308b When the second output terminal 324b (source), holes and electrons enter the organic functional layer 330 through the first channel 308a and the second channel 308b respectively, and then recombine in the organic functional layer 330 to excite light.

When the first organic thin film transistor 310 is an n-type organic thin film transistor, the second organic thin film transistor 320 is a p-type organic thin film transistor. The principle of the light emitting mechanism of the organic electroluminescent device 300 is generally the same as the above, and will not be described here again.

In other embodiments, the first organic thin film transistor 310 and the second organic thin film transistor 320 in the organic electroluminescent device of the present invention may also have structures different from the above-mentioned embodiments, which will be described below with examples. FIG. 4A is a cross-sectional view of the first organic thin film transistor 310 and the organic functional layer 330 in FIG. 3 . 4B to 4C are cross-sectional views of the first organic thin film transistor 310 and the organic functional layer 330 in other embodiments of the present invention.

Please refer to FIG. 4A first. In the first organic thin film transistor 310 of this embodiment, carriers (holes or electrons) 301 are transmitted from the first input terminal 314a to the first output terminal 314b through the first channel 308a. Please refer to FIG. 4B , in other embodiments, the first insulating layer 306a may also be located between the first input terminal 314a and the first output terminal 314b, and the first channel 308a is located on the first insulating layer 306a. At this time, the carriers 301 are transmitted from the first input end 314a to the first output end 314b through the upper first channel 308a.

Referring to FIG. 4C , the organic functional layer 330 may also be interposed between the first input terminal 314 a and the first output terminal 314 b of the first organic thin film transistor 310 . At this time, the carriers (holes or electrons) 301 are transmitted from the first input terminal 314a to the first output terminal 314b through the lower first channel 308a.

The structure of the second organic thin film transistor 320 of the present invention can also be changed as described above for the first organic thin film transistor 310, and combined with any of the above first organic thin film transistors 310 to form the organic electroluminescence element of the present invention. Those skilled in the art can select the forms of the first organic thin film transistor and the second organic thin film transistor of the organic electroluminescent element according to the present invention, which is not limited by the present invention.

The light emitting mechanism of the organic electroluminescent device of the present invention will be described below by taking the organic electroluminescent device shown in FIG. 3 as an example. The following description takes the p-type first organic thin film transistor 310 and the n-type second organic thin film transistor 320 as examples, but it is not intended to limit the conductivity of the first organic thin film transistor 310 and the second organic thin film transistor 320 of the present invention. type. Those skilled in the art will know that the first organic thin film transistor 310 can also be an n-type organic thin film transistor, and the second organic thin film transistor 320 can also be a p-type organic thin film transistor.

Please refer to FIG. 3 again, if the voltages applied to the first control terminal 312 of the first organic thin film transistor 310 and the second control terminal 322 of the second organic thin film transistor 320 are respectively greater than the voltages of the first organic thin film transistor 310 and the second organic thin film transistor The threshold voltage or threshold voltage of the thin film transistor 320, then the hole will move in the first channel 308a between the first input terminal 314a and the first output terminal 314b, and the electrons will move between the second input terminal 324a and the first output terminal 314b. The second channel 308b moves between the two output terminals 324b. Since there is a potential difference between the first control terminal 312 and the second control terminal 322, in addition to the holes and electrons moving in the first channel 308a and the second channel 308b respectively, they will also be caused by the first control terminal 312 and the second control terminal 322. The potential difference between the terminals 322 moves to the organic functional layer 330, and recombines in the organic functional layer 330, so that the organic functional layer 330 emits light. The first control terminal 312, the first input terminal 314a and the first output terminal 314b of the first organic thin film transistor 310 and the second control terminal 322, the second input terminal 324a and the second output terminal 324b of the second organic thin film transistor 320 The material is, for example, conductive metal oxide, and the light emitted by the organic functional layer 330 can be emitted from any direction of the organic electroluminescent device 300 , thus making the organic electroluminescent device 300 have better luminous efficiency.

The application of the above-mentioned organic electroluminescent element in an active organic electroluminescent display panel will be described below.

FIG. 5 is a schematic circuit diagram of a pixel array of an organic electroluminescent device according to a preferred embodiment of the present invention. Referring to FIG. 5 , the pixel array 800 of the organic electroluminescent device is composed of, for example, a pixel structure 820 of the organic electroluminescent device, a first scan line 808 , a second scan line 810 and a data line 812 .

As mentioned above, the pixel structure 820 of the organic electroluminescent device includes an organic electroluminescent device 300 , a switching device 802 and a charge storage device 816 . The organic electroluminescence device 300 includes a first organic thin film transistor 310 , a second organic thin film transistor 320 and at least one organic functional layer 330 (see FIG. 3 ). Wherein, the second control terminal 322 of the second organic thin film transistor 320 is connected to the first output terminal 314b of the first organic thin film transistor 310, and the first control terminal 312 of the first organic thin film transistor 310 is connected through the organic functional layer 330 And connected to the second control terminal 322 of the second organic thin film transistor 320 .

The switch element 802 has a third input terminal I, a third output terminal 0 and a third control terminal G, and the third output terminal 0 is connected to the first input terminal 314 a of the first organic thin film transistor 310 . In a preferred embodiment, the switch element 802 includes at least one thin film transistor, which can be an n-type or p-type thin film transistor. The charge storage element 816 includes at least one capacitor connected to the first output terminal 314 b of the first organic thin film transistor 310 and the second input terminal 324 a of the second organic thin film transistor 320 .

Please continue to refer to FIG. 5, the first scanning line 808 is connected to the third control terminal G of the switching element 802, the data line 812 is connected to the third input terminal I of the switching element 802, and the second scanning line 810 is connected to The first control terminal 312 of the first organic thin film transistor 310 .

An example will be given below to illustrate the driving method of the pixel array of the above-mentioned active organic electroluminescence device. In the following embodiments, the switching element 802 and the first organic thin film transistor 310 are, for example, n-type, while the second organic thin film transistor 320 is, for example, p-type.

FIG. 6 is a waveform diagram of voltage signals input into the first scan line and the second scan line shown in FIG. 5 . Please refer to FIG. 5 and FIG. 6 at the same time. Firstly, in step 1, the switch element 802 and the first organic thin film transistor 310 are turned on, and the second organic thin film transistor 320 is turned off. For example, voltage signals are first input from the first scanning line 808 and the second scanning line 810 to turn on the switching element 802 and the first organic thin film transistor 310, and are controlled by the voltage signal input to the first organic thin film transistor 310. The potential of the second pulling terminal 322 of the second organic thin film transistor 320 is used to maintain the second organic thin film transistor 320 in an off state. Then, a data signal is input through the data line 812 , and the data signal will be transmitted to the charge storage element 816 through the switch element 802 and the first organic thin film transistor 310 in the on state and stored therein. Afterwards, in step 2, the switching element 802 is turned off, and the voltage value input by the second scanning line 810 is changed to turn on the second organic thin film transistor 320 . At this time, a potential difference will be generated between the first control terminal 312 of the first organic thin film transistor 310 and the second control terminal 322 of the second organic thin film transistor 320, and the charge storage element 816 will also output the data stored therein. signal, in the first organic thin film transistor 310, the carrier moving from the first input terminal 314a to the first output terminal 314b and the carrier moving from the second input terminal 324a to the second output terminal 324b in the second organic thin film transistor 320 Carriers will also move to the organic functional layer 330 (see FIG. 3 ) between the first control terminal 312 of the first organic thin film transistor 310 and the second control terminal 322 of the second organic thin film transistor 320 at the same time, and the carriers (holes) and electrons) will recombine therein, and then make the organic electroluminescence device 300 emit light.

In summary, the present invention integrates organic thin film transistors and organic electroluminescent elements to improve the reliability of the manufacturing process and solve the problem that the aperture ratio of conventional active organic electroluminescent displays is limited by the size of the thin film transistors. question. If the present invention is applied to an active organic electroluminescent display, since the pixel size is equal to that of an organic thin film transistor, the aperture ratio and resolution of the display can be effectively improved.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, this The scope of protection of the invention shall be defined by the scope of the appended patent application.

Claims (16)

1, a kind of organic electroluminescent element is characterized in that it comprises:

One first OTFT has one first control end, a first input end, one first output and a first passage, and first passage is between the first input end and first output;

One second OTFT has one second control end, one second input, one second output and a second channel, and second channel is between second input and second output; And

Second OTFT and the first OTFT upper and lower settings, at least one organic functional layer is folded between second OTFT and first OTFT.

2, organic electroluminescent element according to claim 1, it is characterized in that wherein the organic functional layer be folded between first passage and the second channel respectively, between first input end and first output or between second input and second output.

3, organic electroluminescent element according to claim 1 is characterized in that the projecting direction of first passage wherein is perpendicular to the projecting direction of second channel.

4, organic electroluminescent element according to claim 1 is characterized in that wherein first OTFT is a p type OTFT, and second OTFT is a n type OTFT.

5, organic electroluminescent element according to claim 4 is characterized in that wherein first input end is to be source electrode, and first output is to be drain electrode, and second input is to be drain electrode, and second output is to be source electrode.

6, organic electroluminescent element according to claim 1 is characterized in that wherein first OTFT is a n type OTFT, and second OTFT is a p type OTFT.

7, organic electroluminescent element according to claim 6 is characterized in that wherein first input end is to be drain electrode, and first output is to be source electrode, and second input is to be source electrode, and second output is to be drain electrode.

8, organic electroluminescent element according to claim 1 is characterized in that wherein first passage is arranged on first control end, and second channel is arranged under second control end.

9, organic electroluminescent element according to claim 8 is characterized in that it more comprises one first insulating barrier and one second insulating barrier, and it is to be arranged at respectively between first control end and the first passage, between second control end and the second channel.

10, organic electroluminescent element according to claim 9, wherein first insulating barrier is to be arranged between the first input end and first output, first passage is arranged on first insulating barrier.

11, organic electroluminescent element according to claim 9, wherein second insulating barrier is to be arranged between second input and second output, second channel is arranged under second insulating barrier.

12, organic electroluminescent element according to claim 9 is characterized in that wherein first input end and first output or second input and second output are to be arranged in the organic functional layer.

13, organic electroluminescent element according to claim 1 is characterized in that wherein the material of first control end, first input end, first output, second control end, second input and second output is the metal oxide of electric conducting material or conduction.

14, a kind of dot structure of organic electroluminescent element is characterized in that it comprises:

One organic electroluminescent element as claimed in claim 1, wherein second control end of second OTFT is first output that is linked to first OTFT, and first control end of first OTFT is to link with second control end of second OTFT by the organic functional layer;

One switch element has one the 3rd control end, one the 3rd input and one the 3rd output, and the 3rd output is linked to the first input end of first OTFT; And

One charge storage element is linked to first output of first OTFT and second input of second OTFT.

15, a kind of pel array of organic electroluminescent element is characterized in that it comprises:

Dot structure just like the described organic electroluminescent element of claim 14;

One first scan line is linked to the 3rd control end of switch element;

One data line is linked to the 3rd input of switch element; And

One second scan line is linked to first control end of first OTFT.

16, a kind of driving method of organic electroluminescent element is suitable for driving the pel array just like the described organic electroluminescent element of claim 15, it is characterized in that it comprises the following steps:

Import two voltages opening the switch element and first OTFT respectively, and make second OTFT maintain closed condition;

Import a document signal, it is stored in the charge storage element; And

The off switch element, and change inputs to the magnitude of voltage of first OTFT, opening second OTFT, and between first OTFT and second OTFT, produce a potential difference, to drive organic electroluminescent element.

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