KR20040025998A - Organic light-emitting device - Google Patents

Abstract

PURPOSE: An organic electro-luminescence device is provided to enhance the efficiency and the productivity by increasing a degree of integration and simplifying a total structure. CONSTITUTION: An organic electro-luminescence device includes a substrate(102), a cathode electrode(104), an organic layer, a gate electrode(114), and an anode electrode(118). The cathode electrode(104) is formed on the substrate(102). The organic layer is formed on the cathode electrode in order to generate the light according to a controlled voltage. The gate electrode(114) is used for controlling the emission of the organic layer on the basis of the control voltage of the outside. The anode electrode(118) is formed on the gate electrode. An insulating layer is formed between the gate electrode and the anode electrode. The gate electrode, the insulating layer, and the anode electrode are operated as a capacitor.

Description

Organic light emitting element {ORGANIC LIGHT-EMITTING DEVICE}

The present invention relates to a flat panel display device, and more particularly, to an organic light emitting device suitable for displaying a target color image through light emission by recombination energy of electrons and holes injected from the outside. to improve the structure of an organic light-emitting device.

Recently, with the development of semiconductor manufacturing technology and image processing technology, commercialization and widespread use of flat panel display devices that can easily achieve light weight, thinness, and high image quality are rapidly progressing. Organic light emitting devices having many advantages, such as ease of use, simplicity of process, and flexibility of structure, have been spotlighted as next generation display devices.

Such an organic light emitting device has characteristics superior to an inorganic light emitting device in terms of excellent luminous efficiency, ease of large area, simplicity of process, direct current low voltage driving, high speed response, and multicoloring, and include a positive electrode (anode electrode) and a negative electrode (cathode electrode). Is used to inject electrons and holes from the outside, and display arbitrary images on the panel through light emission by their recombination energy.

To this end, a driving circuit element for driving the device, that is, a plurality of transistors and capacitors (for example, a plurality of organic light emitting diodes) having a diode structure in which a multilayer organic material layer is deposited between two metal electrodes of a positive electrode and a negative electrode is used. For example, four transistors and two capacitors) are formed. Here, a group of transistors perform a function of supplying a current to the light emitting diode, another group of transistors perform a function of controlling a current driving transistor, and a capacitor is used to constant the gate voltage of the transistor controlling the current supply transistor. It performs the function of maintaining.

However, the conventional organic light emitting device having the structure as described above has a problem that not only the degree of integration decreases significantly but also the overall structure becomes complicated because the driving circuit elements must be formed around each device, and many devices are provided in one pixel. Since the light emitting area is reduced and the aperture ratio is reduced, the display efficiency is inevitably deteriorated.

In addition, the conventional organic light emitting device has a problem that productivity of the organic light emitting device is lowered because the driving circuit device must be formed around the organic light emitting device by repeatedly performing a complex process such as a photo process and an etching process.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is to provide an organic light emitting device capable of realizing high integration and structure simplification by integrally forming a driving circuit element in an organic light emitting device.

Another object of the present invention is to provide an organic light emitting device that can realize high integration and structure simplification by forming a driving circuit element in an organic light emitting device as an integral type of vertical structure.

Still another object of the present invention is to provide an organic light emitting device capable of increasing its productivity by integrally forming a driving circuit device in an organic light emitting device.

Still another object of the present invention is to provide an organic light emitting device capable of increasing the display efficiency of an organic light emitting device by integrally forming a driving circuit device in the organic light emitting device and expanding its light emitting area.

According to an aspect of the present invention, there is provided an organic light emitting device for displaying an image by emitting organic light, the anode comprising: a negative electrode formed on a substrate; An organic layer formed on the negative electrode to emit light according to voltage control; A gate electrode controlling light emission of the organic layer based on a control voltage applied from the outside; And it provides an organic light emitting device consisting of a positive electrode formed on the gate electrode.

According to another aspect of the present invention, there is provided an organic light emitting device for displaying an image through organic light emission, comprising: a positive electrode formed on a substrate; A gate electrode formed on the positive electrode to control light emission of the organic layer based on a control voltage applied from the outside; An organic layer formed on the gate electrode and emitting light according to voltage control from the gate electrode; And it provides an organic light emitting device consisting of a negative electrode formed on the organic layer.

1A is a cross-sectional view of an organic light emitting diode according to a first embodiment of the present invention;

1B is a cross-sectional view of an organic light emitting diode according to a modified embodiment of the first embodiment of the present disclosure;

2A is a cross-sectional view of an organic light emitting diode according to a second embodiment of the present disclosure;

2B is a cross-sectional view of an organic light emitting diode according to a modified embodiment of the second embodiment of the present disclosure;

3A is a cross-sectional view of an organic light emitting diode according to a third embodiment of the present disclosure;

3B is a cross-sectional view of an organic light emitting diode according to a modified embodiment of the third embodiment of the present invention;

4A is a cross-sectional view of an organic light emitting diode according to a fourth embodiment of the present disclosure;

4B is a cross-sectional view of an organic light emitting diode according to a modified embodiment of the fourth embodiment of the present invention;

5A is a cross-sectional view of an organic light emitting diode according to a fifth embodiment of the present disclosure;

5B is a cross-sectional view of an organic light emitting diode according to a modified embodiment of the fifth embodiment of the present invention;

6 is a graph illustrating an experimental result of a current characteristic in which a current flowing between a positive electrode and a negative electrode changes according to a gate voltage value in the organic light emitting diode according to the first embodiment;

FIG. 7 illustrates an experimental result of current characteristics when a voltage applied to a gate electrode is changed from -10V to + 10V while the voltage between the positive electrode and the negative electrode is fixed at -10V in the organic light emitting device according to the first embodiment. Graph showing.

<Description of the code | symbol about the principal part of drawing>

102, 202, 302, 402, 502: substrate

104, 204, 304, 404, 504: negative electrode

106, 206, 306, 406, 506: hole injection layer

108, 208, 308, 408, 508: hole transport layer

110, 210, 310, 410, 510: light emitting layer

112, 212, 312, 412, 512: surface treatment layer

114, 218, 314, 414, 514: gate electrodes

116, 216, 316, 416, 516: electron injection and transport layer

118, 214, 318, 418, 518: positive electrode

220, 320, 420: Capacitor

222, 324, 424: capacitor electrodes

224, 322, 422: capacitor insulating film

520: organic transistor

522: organic material layer

524, 528: metal electrode

526: insulating film

The above and other objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

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

First, a key technical aspect of the present invention is a conventional structure in which a pixel structure is a diode structure in which a multilayer organic material layer is deposited between a positive electrode and a negative electrode, and a plurality of driving circuit elements (ie, transistors and capacitors) are formed around the pixel. Unlike organic light emitting devices, a gate electrode is formed in an organic layer between a positive electrode and a negative electrode, a capacitor is formed in a predetermined portion of a wiring portion of the gate electrode, a capacitor is formed using a positive electrode, or a driving transistor is formed using a positive electrode. By improving the structure of the organic light emitting device in a manner to form a, it is possible to easily achieve the object of the present invention through this technical means.

[First Embodiment]

1A is a cross-sectional view of an organic light emitting diode according to a first embodiment of the present invention, wherein the organic light emitting diode includes a substrate 102, a negative electrode 104, a hole injection layer 106, a hole transport layer 108, and a light emitting layer 110. ), The surface treatment layer 112, the gate electrode 114, the electron injection and transport layer 116, and the positive electrode 118 are sequentially stacked in an arbitrary pattern.

Referring to FIG. 1A, the organic light emitting diode according to the present exemplary embodiment deposits a hole injection layer 106 and a hole transport layer 108 on a negative electrode 104, and deposits a light emitting layer 110 and a surface treatment layer 112 thereon. After that, the gate electrode 114 is formed on the upper portion, and the electron injection and transport layer 116 and the positive electrode 118 are formed thereon. Most of the organic materials used in the organic light emitting device have semiconductor properties. . Therefore, due to this semiconductor property, it is possible to increase or decrease the concentration of charge carriers inside the organic semiconductor layer by applying an electric field externally. Herein, the surface treatment layer 112 may be formed through SAM treatment, thin film buffer layer formation, RIE treatment, and the like, and is used to adjust the work function between the gate electrode 114 and the organic material layer.

To this end, in this embodiment, using this property, another metal electrode, that is, the gate electrode 114 is formed in the organic layer, and a voltage is applied to the gate electrode 114 to cause a change in the electric field in the organic layer. By controlling the concentration and behavior of the charge carriers. Here, the gate electrode 114 may be formed of a metal or may be formed using a metallic conductive polymer rather than a metal.

That is, the voltage applied to the gate electrode 114 is controlled by applying a voltage to the positive electrode 118 and the negative electrode 104 to form an electric field inside the device, thereby changing the concentration of charge in the organic light emitting layer, The amount of light emitted from the device is controlled by reducing the current flowing through the light emitting layer 110 by bypassing the gate electrode 114.

According to the present embodiment, conventionally, two transistors for supplying current to the periphery of the organic light emitting device, two transistors for controlling the current driving transistor, and two or more for maintaining a constant gate voltage of the control transistor. Although the pixel was formed by forming a capacitor, in the present invention, a gate electrode is formed inside the organic layer, and light emission of the light emitting device is controlled by controlling current applied to the formed gate electrode.

On the other hand, since the processes of manufacturing the organic light emitting device according to the present embodiment can be sufficiently realized by manufacturing methods well known in the art, detailed description thereof will be omitted.

The inventors of the present invention conducted an experiment on the current characteristics using the organic light emitting device manufactured according to the present embodiment, the test results are as shown in Figs.

6 is a graph illustrating an experimental result of a current characteristic in which a current flowing between a positive electrode and a negative electrode changes according to a gate voltage value in the organic light emitting diode according to the first embodiment.

Referring to FIG. 6, it can be easily seen that the current flowing between the positive electrode 118 and the negative electrode 104 is controlled according to the voltage value of the gate electrode 114. When the voltage of the gate electrode 114 is -2V or higher, the current is controlled. It can be seen that the organic light emitting device is turned off since the constant is almost 0A, and it can be seen that the organic light emitting device is turned on and emits light when the voltage V _G of the gate electrode 114 is -8V to -10V. In Fig. 6, reference numeral LP denotes a light emitting point, a denotes an unluminous area, and b denotes a light emitting area, respectively.

FIG. 7 illustrates an experimental result of current characteristics when a voltage applied to a gate electrode is changed from -10V to + 10V while the voltage between the positive electrode and the negative electrode is fixed at -10V in the organic light emitting device according to the first embodiment. Is a graph showing

Referring to FIG. 7, it can be easily seen that light emission of the organic layer may be controlled by adjusting a voltage value applied to the gate electrode 114. In Fig. 7, reference numeral LP denotes a light emitting point, a denotes an unluminous area, and b denotes a light emitting area, respectively.

In the present embodiment, the negative electrode 104 is formed on the substrate 102 and the positive electrode 118 is formed on the opposite side with the organic layer and the gate electrode 114 interposed therebetween. The invention is not necessarily limited thereto, and as an example, as shown in FIG. 1B, a positive electrode 118 is formed on the side of the substrate 102, and a gate electrode 114, an organic layer, and a negative electrode are formed on the substrate 102. It is a matter of course that the structure 104 may be formed to be sequentially stacked. Of course, the organic light emitting device of the present modified embodiment may have substantially the same result as the organic light emitting device of the first embodiment described above, even with such an opposite structure.

Therefore, the organic light emitting device of this embodiment does not form a separate driving circuit device (a plurality of transistors and capacitors) around the device as in the conventional device, and emits light of the device using a gate electrode formed in the organic layer. Because of having a structure to control, not only the degree of integration of the organic light emitting device can be greatly improved, but the overall structure can be simplified.

In addition, since the organic light emitting device according to the present embodiment does not need to allocate a separate area of the driving circuit element around the organic light emitting device, the light emitting area can be increased to increase the aperture ratio, thereby improving display efficiency. have.

Furthermore, the organic light emitting device of the present embodiment can reduce the process of forming the driving circuit element around the organic light emitting device can significantly reduce the overall manufacturing process can improve the productivity of the organic light emitting device.

Second Embodiment

2A is a cross-sectional view of an organic light emitting diode according to a second exemplary embodiment of the present invention. The organic light emitting diode of the present exemplary embodiment includes a negative electrode 204, a hole injection layer 206, a hole transport layer 208, and a substrate on a substrate 202. The structure of sequentially stacking the light emitting layer 210 and the surface treatment layer 212 is substantially the same as that of the first embodiment described above.

However, the organic light emitting device of the present embodiment has a structure in which the gate electrode 114 is formed on the surface treatment layer 112 and the electron injection and transport layer 116 and the positive electrode 118 are sequentially formed thereon. Unlike the first embodiment, the positive electrode 214 is first formed on the surface treatment layer 212, and the insulating layer 216 and the gate electrode 218 are sequentially formed thereon.

Therefore, the organic light emitting device of the present embodiment has a principle of driving the device by the field effect in the organic layer because the insulating film 216 is formed between the positive electrode 214 and the gate electrode 218. That is, in the organic light emitting device of the present embodiment, reference numeral 220 functions as a capacitor.

In the present embodiment, the negative electrode 204 is formed on the substrate 202 and the gate electrode 218 and the capacitor 220 are formed on the opposite side with the organic layer and the positive electrode 214 interposed therebetween. Although the present invention is not limited thereto, as shown in FIG. 2B, the gate electrode 218 is first formed on the side of the substrate 202 and the insulating film 216 is formed thereon. Of course, the positive electrode 214, the organic layer and the negative electrode 204 may be formed in a stacked structure. Of course, the organic light emitting device of the present modified embodiment may have substantially the same result as the organic light emitting device of the above-described second embodiment even with such a reverse structure.

Therefore, the organic light emitting device according to the present embodiment can obtain the same result (effect) as in the first embodiment described above, and compared with the first embodiment described above, the capacitor using the positive electrode and the gate electrode. Because it forms a further has a side effect that can expect a field effect in the organic layer.

Third Embodiment

3A is a cross-sectional view of an organic light emitting diode according to a third exemplary embodiment of the present invention. The organic light emitting diode according to the present exemplary embodiment includes a negative electrode 304, a hole injection layer 306, a hole transport layer 308, and a substrate on a substrate 302. In view of the structural aspect in which the light emitting layer 310, the surface treatment layer 312, the gate electrode 314, the electron injection and transport layer 316, and the positive electrode 318 are sequentially stacked in an arbitrary pattern, the above-described first embodiment It is substantially the same as that of the example. Therefore, hereinafter, description of substantially identical structures will be omitted in order to avoid unnecessary overlapping materials.

However, the organic light emitting device of the present embodiment differs from that of the first embodiment in that the capacitor 320 is further formed on the extension line of the gate electrode 314 (that is, the wiring portion of the gate electrode).

That is, in the organic light emitting diode of the present embodiment, the capacitor electrode 322 is formed on the organic substrate 302 on the same line as the negative electrode 304, the capacitor insulating film 324 is formed thereon, and the upper portion of the capacitor insulating film 324 is formed. A line of the gate electrode 314 is formed in the film. Here, the capacitor electrode 322 may be formed at the same time when the negative electrode 304 is formed or may be formed through a separate process, and the capacitor insulating film 324 may be formed at the same time when the hole injection layer 306 is formed, or It can be formed through the process.

Here, the capacitor 320 serves to adjust the voltage applied to the gate electrode 314 formed in the organic light emitting layer, and also serves to block leakage current from flowing through the gate electrode 314.

Meanwhile, in the present embodiment, the negative electrode 304 is formed on the substrate 302 and the positive electrode 318 is formed on the opposite side with the organic layer and the gate electrode 314 interposed therebetween. As an example, as illustrated in FIG. 3B, the positive electrode 318 is first formed on the side of the substrate 302 and the gate electrode 314, the organic layer, and the negative electrode are formed on the substrate 302. Of course, it is also possible to form a structure in which 304 is sequentially stacked. Of course, the organic light emitting device of the present modified embodiment may have substantially the same result as the organic light emitting device of the above-described third embodiment even with such an opposite structure.

Therefore, the organic light emitting device according to the present embodiment can obtain the same result (effect) as in the first embodiment described above, and compared with the first embodiment described above, the capacitor formed in the wiring portion of the gate electrode. Since blocking the leakage current through the has a side effect of reducing the current consumption of the organic light emitting device.

[Example 4]

4A is a cross-sectional view of an organic light emitting diode according to a fourth exemplary embodiment of the present invention. The organic light emitting diode of the present exemplary embodiment includes a negative electrode 404, a hole injection layer 406, a hole transport layer 408, and a substrate on a substrate 402. In view of the structural aspect in which the light emitting layer 410, the surface treatment layer 412, the gate electrode 414, the electron injection and transport layer 416, and the positive electrode 418 are sequentially stacked in an arbitrary pattern, the first embodiment described above It is substantially the same as that of the example and the third embodiment. Therefore, hereinafter, description of substantially identical structures will be omitted in order to avoid unnecessary overlapping materials.

However, the organic light emitting device according to the present embodiment differs from the above-described third embodiment in which the capacitor is formed at the wiring portion of the gate electrode, and the capacitor 420 is formed on the positive electrode 418.

More specifically, in the organic light emitting device of the present embodiment, the capacitor insulating film 422 is formed on the positive electrode 418, and the capacitor electrode 424 is formed thereon, that is, in the above-described third embodiment, the capacitor has a horizontal structure. In contrast, in the present embodiment, the capacitor is formed in a vertical structure.

Meanwhile, in the present embodiment, the negative electrode 404 is formed on the substrate 402, the positive electrode 418 is formed on the opposite side with the organic layer and the gate electrode 414 interposed therebetween, and then the capacitor 420 is formed thereon. Although the present invention is not limited thereto, as shown in FIG. 4B, as shown in FIG. 4B, the capacitor electrode 424 is first formed on the substrate 402 side as opposed to the above. It is a matter of course that the capacitor insulating film 422, the positive electrode 418, the gate electrode 414, the organic layer and the negative electrode 404 are sequentially stacked on the above. Of course, the organic light emitting device of the present modified embodiment may have substantially the same result as the organic light emitting device of the above-described fourth embodiment even with such an opposite structure.

Therefore, substantially the same results (effects) as in the above-described third embodiment can be obtained, and further have the side effect of further improving the integration density by forming the capacitor in a vertical structure instead of a horizontal structure.

[Example 5]

5A is a cross-sectional view of an organic light emitting diode according to a fifth exemplary embodiment of the present invention. The organic light emitting diode of the present exemplary embodiment includes a negative electrode 504, a hole injection layer 506, a hole transport layer 508, and a substrate on a substrate 502. In view of the structural aspect in which the light emitting layer 510, the surface treatment layer 512, the gate electrode 514, the electron injection and transport layer 516, and the positive electrode 518 are sequentially stacked in an arbitrary pattern, the above-described first, Substantially the same as that of the second, third and fourth embodiments. Therefore, hereinafter, description of substantially identical structures will be omitted in order to avoid unnecessary overlapping materials.

However, the organic light emitting diode according to the present exemplary embodiment differs from that of the first exemplary embodiment in that the organic transistor 520 is further formed on the positive electrode 518. Here, the organic transistor 520 can be used as a driving circuit element.

That is, in the organic light emitting device according to the present embodiment, after all the structures of the organic light emitting device are formed, the organic layer 522, the first metal electrode 524, the insulating film 526, and the second metal on the positive electrode 518. The electrodes 528 are formed by sequentially stacking the electrodes 528.

Meanwhile, in the present embodiment, the negative electrode 504 is formed on the substrate 502, and the positive electrode 518 is formed on the opposite side with the organic layer and the gate electrode 514 interposed therebetween, and the organic transistor 520 is formed thereon. Although the present invention is not necessarily limited thereto, as shown in FIG. 5B, the organic transistor 520 is first formed on the substrate 502 side as opposed to the above. Of course, the positive electrode 518, the gate electrode 514, the organic layer, and the negative electrode 504 may be sequentially stacked on the substrate. Of course, the organic light emitting device of the present modified embodiment may have substantially the same result as the organic light emitting device of the above-described fifth embodiment even with such a reverse structure.

Therefore, the organic light emitting device according to the present embodiment can obtain the same result (effect) as in the first embodiment described above, and compared with the first embodiment, the capacitor for the driving circuit element on the upper part of the positive electrode. Since it further forms a further has a side effect that can further realize high integration of the organic light emitting device.

On the other hand, the present embodiment has been described as forming only one transistor on top of the organic light emitting device, but the present invention is not necessarily limited thereto, and a transistor having a multilayer structure on top of the organic light emitting device according to need or use. It will be appreciated that those skilled in the art will readily understand such technical variations.

As described above, according to the present invention, unlike the conventional organic light emitting device in which the pixel structure is a diode structure in which a multilayer organic material layer is deposited between the positive electrode and the negative electrode, and a plurality of driving circuit elements are formed around the pixel, the positive electrode Forming a gate electrode in the organic layer between the negative electrode and the negative electrode, forming a capacitor in a predetermined portion of the wiring portion of the gate electrode, forming a capacitor using the positive electrode, or forming a driving transistor using the positive electrode. Not only can it greatly increase the degree of integration, but also the overall structure can be simplified, and the efficiency of the display can be improved by increasing the aperture area by increasing the light emitting area, and greatly reducing the overall manufacturing process, thereby increasing the productivity of the organic light emitting device. You can.

Claims (16)

In the organic light emitting device for displaying an image by emitting organic light, A negative electrode formed on the substrate; An organic layer formed on the negative electrode to emit light according to voltage control; A gate electrode controlling light emission of the organic layer based on a control voltage applied from the outside; And An organic light emitting device comprising a positive electrode formed on the gate electrode. The organic light emitting device of claim 1, wherein an insulating film is formed between the gate electrode and the positive electrode, and the gate electrode, the insulating film, and the positive electrode function as a capacitor. The organic light emitting diode of claim 1, further comprising a capacitor formed of an insulating film and a capacitor electrode at a wiring portion of the gate electrode. The organic light emitting diode of claim 1, wherein the organic light emitting diode further comprises a capacitor formed on the positive electrode and an insulating film and a capacitor electrode. The organic light emitting diode of claim 1, further comprising a transistor formed of two metal electrodes sequentially stacked on the positive electrode with an insulating film therebetween. The organic light emitting device of claim 1, wherein the organic light emitting device further comprises a transistor having a multilayer structure formed of N metal electrodes sequentially stacked on the positive electrode with an insulating film therebetween. The organic light emitting device according to any one of claims 1 to 6, wherein the gate electrode is a metallic conductive polymer. The organic light emitting device of any one of claims 1 to 6, wherein the organic light emitting device further comprises a surface treatment layer for adjusting a work function between the gate electrode and the organic material layer. In the organic light emitting device for displaying an image by emitting organic light, A positive electrode formed on the substrate; A gate electrode formed on the positive electrode to control light emission of the organic layer based on a control voltage applied from the outside; An organic layer formed on the gate electrode and emitting light according to voltage control from the gate electrode; And An organic light emitting device consisting of a negative electrode formed on the organic layer. The organic light emitting diode of claim 9, wherein an insulating film is formed between the positive electrode and the gate electrode, and the positive electrode, the insulating film, and the gate electrode function as a capacitor. The organic light emitting diode of claim 9, wherein the organic light emitting diode further comprises a capacitor formed of an insulating film and a capacitor electrode at a wiring portion of the gate electrode. The organic light emitting diode of claim 9, wherein the organic light emitting diode further comprises a capacitor formed between the positive electrode and the substrate as an insulating film and a capacitor electrode. The organic light emitting device of claim 9, wherein the organic light emitting device further comprises a transistor formed by sequentially stacking another organic material layer, a first metal, an insulating film, and a second metal between the positive electrode and the substrate. 10. The organic light emitting diode of claim 9, wherein the organic light emitting diode further comprises a transistor having a multilayer structure in which another organic material layer, a first metal, an insulating film, and a second metal are sequentially stacked N-th order between the positive electrode and the substrate. An organic light emitting element. The organic light emitting device according to any one of claims 9 to 14, wherein the gate electrode is a metallic conductive polymer. The organic light emitting device of any one of claims 9 to 14, wherein the organic light emitting device further comprises a surface treatment layer for adjusting a work function between the gate electrode and the organic material layer.