KR100637253B1 - Organic light emitting display apparatus - Google Patents

Abstract

An organic light emitting display device is provided to prevent a gate electrode from being peeled off by contacting at least a portion of a bottom surface of the gate electrode with an upper surface of an insulation film. A first capacitor electrode, a source electrode, a drain electrode, and a pixel electrode(131) are arranged on a substrate(100). An insulation film(101) includes a first aperture for exposing facing portions between the first source electrode and the drain electrode, and a second aperture for exposing at least a portion of the pixel electrode. An organic semiconductor layer(127) is contacted with the source and drain electrodes within the first aperture. A gate insulation film(102) covers the organic semiconductor layer within the first aperture. A second capacitor electrode is arranged on the insulation film. A gate electrode(121) is arranged on the gate insulation film. A passivation layer(104) covers the second capacitor electrode and the gate electrode, so that at least a portion of the pixel electrode is exposed. An intermediate layer(133) is arranged on an exposed portion of the pixel electrode. A third capacitor electrode is electrically connected to the first capacitor electrode via a contact hole. A counter electrode(134) is arranged on the intermediate layer.

Description

Organic light emitting display apparatus

1 is a cross-sectional view schematically illustrating an organic light emitting display device according to an exemplary embodiment of the present invention.

FIG. 2 is a circuit diagram schematically illustrating a partial pixel of the organic light emitting display device of FIG. 1.

3 is a cross-sectional view schematically illustrating a modified example of the organic light emitting display device illustrated in FIG. 1.

4 is a cross-sectional view schematically illustrating an organic light emitting display device according to another exemplary embodiment of the present invention.

5 is a schematic cross-sectional view of an organic light emitting display device according to another exemplary embodiment of the present invention.

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

100: substrate 101: insulating film

102 gate insulating film 104 passivation film

110: capacitor 111: first capacitor electrode

112: second capacitor electrode 113: third capacitor electrode

120: organic thin film transistor 121: gate electrode

123: source electrode and drain electrode 127: organic semiconductor layer

130: organic light emitting element 131: pixel electrode

133: intermediate layer 134: counter electrode

The present invention relates to an organic light emitting display device, and more particularly, to prevent the delamination of the gate electrode of the organic thin film transistor, and when implemented as a capacitor and an array, while maintaining a high capacitance of the capacitor, the parasitic capacitance is greatly reduced and the aperture ratio is improved. An organic light emitting display device.

An organic light emitting display device is a display device including a pixel electrode, an organic light emitting element having an opposite electrode facing the electrode and an intermediate layer interposed therebetween. Such organic light emitting display devices include an active matrix (AM) organic light emitting display device and a passive matrix (PM) organic light emitting display device. In an active driving type organic light emitting display device, a thin film transistor is electrically connected to a pixel electrode to control an electrical signal applied to the pixel electrode through the thin film transistor, and the passive driving type organic light emitting display device has a first pattern of a stripe pattern that crosses each other. It is provided with an electrode and a 2nd electrode, and these intersection points become each pixel. The present invention relates to an active driven organic light emitting display device.

Such an active driving type organic light emitting display device includes a capacitor in addition to a thin film transistor electrically connected to a pixel electrode of the organic light emitting diode, and the capacitor maintains a current to the pixel electrode of the organic light emitting diode or improves driving speed. Function In order to efficiently perform this, it is preferable that a capacitor has a large capacitance. However, in the case of the capacitor provided in the conventional organic light emitting display device, there is a problem that the capacitance is not large.

In order to solve this problem, a method of using a material having a high dielectric constant as an insulating film between the both electrodes of the capacitor has been proposed, but the insulating film between the both electrodes of the capacitor becomes a gate insulating film of the thin film transistor, so the high dielectric constant value is eventually increased. The use of the gate insulating film has a problem of increasing parasitic capacitance occurring at the portion where the source electrode, the drain electrode, and the gate electrode overlap in the thin film transistor.

In addition, in the case of the top gate thin film transistor, since the gate electrode is provided on the gate insulating film, there is a problem in that a peeling phenomenon occurs between the gate electrode and the gate insulating film when the gate electrode is in poor contact with the gate insulating film.

The present invention is to solve the various problems including the above problems, while the separation of the gate electrode of the organic thin film transistor is prevented and the parasitic capacitance is significantly reduced while maintaining the high capacitance of the capacitor when implemented as a capacitor and an array An object of the present invention is to provide an organic light emitting display device having an improved aperture ratio.

In order to achieve the above object and various other objects, the present invention provides a substrate comprising: (i) a substrate, (ii) a first capacitor electrode, a source electrode, a drain electrode, and the source electrode; A pixel electrode electrically connected to any one of the drain electrodes, (iii) a first opening exposing opposite portions of the source electrode and the drain electrode and a second opening exposing at least a portion of the pixel electrode; An insulating film covering the first capacitor electrode, (iv) an organic semiconductor layer disposed in the first opening and in contact with the source electrode and the drain electrode, and (v) an organic semiconductor layer disposed in the first opening; A gate insulating film to be covered, (vi) a second capacitor electrode disposed on the insulating film, a gate electrode disposed on the gate insulating film, and (vii) a pixel electrode A passivation film covering the second capacitor electrode and the gate electrode to expose a portion thereof, (viii) an intermediate layer disposed on the exposed portion of the pixel electrode, and (ix) the passivation to correspond to the second capacitor electrode An organic light emitting display device includes a third capacitor electrode disposed on a film and electrically connected to the first capacitor electrode through a contact hole, and an opposite electrode disposed on the intermediate layer.

According to another aspect of the present invention, the gate electrode may be provided in the first opening of the insulating film, and the end surface of the gate electrode may be in contact with the side of the first opening of the insulating film.

According to still another feature of the present invention, at least a part of the lower surface of the gate electrode may be in contact with the upper surface of the insulating film.

According to another feature of the invention, the insulating film may be provided with a photoresist.

According to still another feature of the present invention, the electrically connected to the pixel electrode of the source electrode and the drain electrode may be provided integrally with the pixel electrode.

According to another feature of the present invention, the source electrode and the drain electrode, which are not electrically connected to the pixel electrode, may be provided integrally with the first capacitor electrode.

According to still another feature of the present invention, the second capacitor electrode and the gate electrode may be integrally provided.

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

1 is a cross-sectional view schematically showing an organic light emitting display device according to an exemplary embodiment of the present invention, and FIG. 2 is a circuit diagram schematically showing a portion of the organic light emitting display device of FIG. 1.

1 and 2, an organic light emitting diode 110, an organic thin film transistor 120, a capacitor 130, and another organic thin film transistor 140 are provided on a substrate 100. Herein, the organic thin film transistor 120 of reference numeral 120 is a driving transistor for driving the organic light emitting element 110, and the organic thin film transistor 140 of reference numeral 140 switches an electrical signal to be applied to the organic light emitting element 110. Switching transistor. Of course, the circuit structure of the organic light emitting display device according to the present invention is not limited to the circuit structure shown in FIGS. 1 and 2, and various modifications are possible, such as other electronic elements may be further provided. Hereinafter, for convenience, the interconnection structure of the organic thin film transistor 120, the capacitor 110, and the organic light emitting element 130 will be described.

As the substrate 100, not only a glass substrate but also various plastic substrates such as acrylic may be used, and further, a metal plate may be used. A buffer layer (not shown) may be provided on the substrate 100 as necessary.

On the substrate 100, a pixel electrode 131 electrically connected to a first capacitor electrode 111 formed of a conductive material, a source electrode and a drain electrode 123, and one of the source electrode and the drain electrode 123. It is provided. In this case, as illustrated in FIG. 1, an electrode electrically connected to the pixel electrode 131 among the source electrode and the drain electrode 123 may be integrally provided with the pixel electrode 131. In addition, in FIG. 1, an electrode that is not electrically connected to the pixel electrode 131 among the source electrode and the drain electrode 123 is illustrated as being separated from the first capacitor electrode 111, but it can be seen from the circuit diagram of FIG. 2. As can be seen, these electrodes are electrically connected to each other, and of course, may be integrally provided.

The first capacitor electrode 111, the source electrode and the drain electrode 123, and the pixel electrode 131 may be formed of a conductive material, and may be formed of a transparent material or an opaque material, if necessary. More specifically, as described below, when light is extracted to the outside through the pixel electrode 131, the light is formed of a transparent material, and when it is not extracted to the outside through the pixel electrode 131, it is formed as a reflective electrode. Can be. When formed of a transparent material it may be provided with ITO, IZO, ZnO or In ₂ O ₃ , when used as a reflective electrode Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, W and A reflective film formed of these compounds and the like and an ITO, IZO, ZnO or In ₂ O ₃ film formed thereon may be provided. These electrodes may be formed through deposition using a mask, or may be formed by forming a conductive material layer on the substrate 100 and then patterning the conductive material layer.

The insulating film 101 is provided on the first capacitor electrode 111, the source electrode and the drain electrode 123, and the pixel electrode 131. The insulating film 101 has a first opening and a second opening, the first opening exposing opposite portions of the source electrode and the drain electrode 123, and the second opening at least part of the pixel electrode 131. Expose

The insulating film 101 having such openings may be formed in various ways. For example, the entire surface of a material such as silicon nitride, silicon oxide, aluminum oxide, titanium oxide, hafnium oxide or zirconium oxide may be applied, and then a laser beam may be applied to a predetermined region. The laser ablation technique (LAT) may be used to irradiate and remove only the irradiated portion of the insulating film 101. In addition, the insulating layer 101 may be formed as a photoresist, and then openings may be formed through an exposure and development process. Of course, various other methods can be used. As described later, the insulating film 101 may be formed of a material having a high dielectric constant if necessary.

In the first opening of the insulating layer 101, an organic semiconductor layer 127 is provided in contact with the source electrode and the drain electrode 123, respectively. The organic semiconductor layer 127 may be formed using various methods such as inkjet printing.

The organic semiconductor layer 127 may be, for example, pentacene, tetracene, anthracene, naphthalene, alpha-6-thiophene, alpha-4-thiophene, perylene And derivatives thereof, rubrene and derivatives thereof, coronene and derivatives thereof, perylene tetracarboxylic diimide and derivatives thereof, and perylene tetracarboxylic dianhydride tetracarboxylic dianhydride) and derivatives thereof, polythiophene and derivatives thereof, polyparaphenylenevinylene and derivatives thereof, polyparaphenylene and derivatives thereof, polyfluorene and derivatives thereof, polythiophenevinylene and derivatives thereof, polyti Offen-heterocyclic aromatic copolymers and derivatives thereof, oligothiophenes and derivatives thereof of alpha-5-thiophene, phthalocyanine and derivatives thereof with or without metals, pyromellitic dianhydrides and the like Body, and Meli Pyro be a tick diimide and derivatives thereof, perylene tetracarboxylic acid dianhydride and a material comprising the derivatives, and perylene tetracarboxylic diimide rigs and at least one of their derivatives. When the organic semiconductor material is formed by an inkjet printing method, the organic semiconductor layer 127 may be formed only in a region defined by the insulating film 101.

The gate insulating film 102 is provided in the first opening of the insulating film 101 so as to be disposed on the organic semiconductor layer 127. The gate insulating film 270 may also be formed by an inkjet printing method or the like. When the gate insulating layer 102 is formed by inkjet printing, a material such as parylene, acrylic polymer (PMMA), or epoxy may be used. Of course, the material for forming the gate insulating film 102 is not limited to these organic materials.

The second capacitor electrode 112 is provided on the insulating film 101, and the gate electrode 121 is provided on the gate insulating film 102. The second capacitor electrode 112 and the gate electrode 121 may be electrically connected to each other, and may be integrally formed unlike the illustrated in FIG. 1. The second capacitor electrode 112 and the gate electrode 121 may be formed using various conductive materials, such as Al or MoW.

On the other hand, when a predetermined electrical signal is applied to the gate electrode 121, in order to ensure that the channel formed in the organic semiconductor layer 127 is in contact with each of the source electrode and the drain electrode 123, the gate electrode 121 of the Preferably, the edge and the edge of the source electrode and the drain electrode 123 overlap each other. In this case, when the gate insulating layer 102 having the high dielectric constant is used, parasitic capacitance generated at the overlapping portion of the gate electrode 121, the source electrode, and the drain electrode 123 also increases. Therefore, the gate insulating film 102 is preferably formed of a material having a low dielectric constant value.

A passivation film 104 is provided on the insulating film 101, the second capacitor electrode 112, and the gate electrode 121, and the passivation film 104 is provided to expose at least a portion of the pixel electrode 131. . The intermediate layer 133 is provided on the exposed portion of the pixel electrode 131.

The passivation film 104 may be formed of a material such as silicon oxide, polyimide, or silicon nitride.

The intermediate layer 133 may be provided with low molecular weight or high molecular organic material. When using low molecular weight organic materials, hole injection layer (HIL), hole transport layer (HTL), organic emission layer (EML), electron transport layer (ETL), electron injection layer (EIL) The electron injection layer may be formed by stacking a single or complex structure, and the usable organic materials may be copper phthalocyanine (CuPc), N, N-di (naphthalen-1-yl) -N, N '-Diphenyl-benzidine (N, N'-Di (naphthalene-1-yl) -N, N'-diphenyl-benzidine: NPB), tris-8-hydroxyquinoline aluminum ( Alq3) can be used in various ways. When the intermediate layer is formed of such a low molecular weight organic material, the intermediate layer may be formed by various methods such as a deposition method or an inkjet printing method.

In the case of the polymer organic material, the structure may include a hole transport layer (HTL) and an emission layer (EML). In this case, PEDOT is used as the hole transport layer, and poly phenylenevinylene (PPV) and polyfluorene are used as the emission layer. Polymer organic materials such as (polyfluorene) are used. When the intermediate layer is formed of the polymer organic material, it may be formed using an inkjet printing method or a thermal transfer method.

The third capacitor electrode 113 is provided on the passivation film 104 to correspond to the first capacitor electrode 111 and the second capacitor electrode 112, and the counter electrode 134 is also provided on the intermediate layer 133. . In this case, contact holes are formed in the passivation layer 104 and the insulating layer 101, and the third capacitor electrode 113 is electrically connected to the first capacitor electrode 111.

The third capacitor electrode 113 and the counter electrode 134 may be formed at the same time. The third capacitor electrode 113 and the opposite electrode 134 may be formed at the same time, by a method such as deposition using a mask or patterning after full deposition of a conductive material. Of course, these electrodes may also be formed through an inkjet printing method, or the like, and the third capacitor electrode 113 and the counter electrode 134 may be formed of different materials as necessary.

The intermediate layer 133 including the emission layer receives light and holes from the pixel electrode 131 and the counter electrode 134 to generate light. In this case, the pixel electrode 131 functions as an anode electrode, and the opposite electrode 134 functions as a cathode electrode. Of course, the polarity of the pixel electrode 131 and the counter electrode 134 may be reversed.

Light generated in the intermediate layer 133 including the light emitting layer is extracted to the outside through the pixel electrode 131 or the counter electrode 134, and thus is located on the optical path among the pixel electrode 131 and the counter electrode 134. The electrode may be provided as a transparent electrode, and the other electrode may be provided as a transparent electrode or a reflective electrode.

Accordingly, like the pixel electrode 131 described above, the counter electrode 134 may be provided as a transparent electrode or a reflective electrode. When used as a transparent electrode, Li, Ca, LiF / Ca, LiF / Al, Al, Mg, After the compounds are deposited to face the intermediate layer 133, the auxiliary electrode or the bus electrode line may be formed of a transparent electrode forming material such as ITO, IZO, ZnO, or In ₂ O ₃ thereon. . And when used as a reflective electrode is formed by depositing the above Li, Ca, LiF / Ca, LiF / Al, Al, Mg and their compounds.

In the structure as described above, the capacitor 110 functions to maintain the current to the pixel electrode 131 of the organic light emitting element 130 or to improve the driving speed. In order to efficiently perform this, it is preferable that the capacitance of the capacitor 110 is large. Accordingly, in the organic light emitting display device according to the present embodiment, the capacitor 110 has a triple electrode structure, and the third capacitor electrode 113 is electrically connected to the first capacitor electrode 111, thereby increasing its capacitance. .

In addition, when using the capacitor 110 having such a structure, an increase in capacitance can be obtained without increasing the area of each electrode of the capacitor 110, and as a result, the organic light emitting device 130 can be provided. The opening area can be widened to increase the aperture ratio.

In addition, a material having a high dielectric constant is used as the insulating film 101 interposed between the first capacitor electrode 111 and the second capacitor electrode 112 of the capacitor 110, and the gate insulating film 102 has a material having a low dielectric constant value. By using, the parasitic capacitance of the organic thin film transistor 120 may be lowered while the capacitance of the capacitor 110 may be increased.

3 is a cross-sectional view schematically illustrating a modified example of the organic light emitting display device illustrated in FIG. 1. As shown in FIG. 2, which is a circuit diagram schematically illustrating a subpixel of the organic light emitting display device according to the above-described embodiment, the pixel electrode 131 of the source electrode and the drain electrode 123 of the organic thin film transistor 120 is provided. What is not electrically connected may be electrically connected to the first capacitor electrode 111, and thus, various modifications are possible, such that the electrodes may be integrally formed as illustrated in FIG. 3.

4 is a cross-sectional view schematically illustrating an organic light emitting display device according to another exemplary embodiment of the present invention.

Referring to FIG. 4, the organic light emitting display device according to the present embodiment differs from the organic light emitting display device according to the above-described embodiment and modified examples thereof in the position and shape where the gate electrode 121 is provided.

When the bonding force between the gate electrode 121 and the gate insulating layer 102 below is low, problems such as peeling of the gate electrode 121 from the gate insulating layer 102 may occur. In particular, when the gate insulating layer 102 is formed of an organic material, the bonding force between the gate electrode 121 and the gate insulating layer 102 may be poor. Accordingly, as in the organic light emitting diode display according to another exemplary embodiment of the present invention as shown in FIG. 4, the gate electrode 121 is provided in the first opening of the insulating film 101, but the gate electrode 121 is provided. The end face of can be in contact with the opening side of the insulating film (101). As a result, even when the bonding force between the gate electrode 121 and the gate insulating layer 102 is low, the gate electrode 121 may be prevented from peeling through the bonding force between the gate electrode 121 and the insulating layer 101.

5 is a schematic cross-sectional view of an organic light emitting display device according to another exemplary embodiment of the present invention.

The organic light emitting display device according to the present embodiment differs from the organic light emitting display device according to the above embodiment in that the gate electrode 121 is not disposed in the first opening of the insulating film 101. In particular, at least a portion of the lower surface of the gate electrode 121 is in contact with the upper surface of the insulating film 101 in order to prevent peeling due to poor bonding force between the gate electrode 121 and the gate insulating film 102. It is. As such, at least a part of the lower surface of the gate electrode 121 is in contact with the upper surface of the insulating film 101, so that the gate electrode 121 is peeled even when the bonding force between the gate electrode 121 and the gate insulating film 101 is not good. Can be prevented.

According to the organic light emitting display device of the present invention made as described above, the peeling of the gate electrode of the organic thin film transistor is prevented, and when implemented as a capacitor and an array, while maintaining the high capacitance of the capacitor, while the parasitic capacitance is dramatically reduced, the aperture ratio is improved. You can.

Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (7)

Board; A pixel electrode electrically connected to any one of a first capacitor electrode, a source electrode, a drain electrode, and the source electrode and the drain electrode disposed on the substrate; An insulating film covering the first capacitor electrode and having a first opening exposing opposed portions of the source electrode and the drain electrode and a second opening exposing at least a portion of the pixel electrode; An organic semiconductor layer disposed in the first opening and in contact with the source electrode and the drain electrode, respectively; A gate insulating film disposed in the first opening and covering the organic semiconductor layer; A second capacitor electrode disposed on the insulating film, and a gate electrode disposed on the gate insulating film; A passivation film covering the second capacitor electrode and the gate electrode to expose at least a portion of the pixel electrode; An intermediate layer disposed on the exposed portion of the pixel electrode; And And a third capacitor electrode disposed on the passivation layer so as to correspond to the second capacitor electrode and electrically connected to the first capacitor electrode through a contact hole, and an opposite electrode disposed on the intermediate layer. Organic light emitting display device. The method of claim 1, And the gate electrode is provided in a first opening of the insulating film, and an end surface of the gate electrode is in contact with a side of the first opening of the insulating film. The method of claim 1, And at least a portion of a lower surface of the gate electrode is in contact with an upper surface of the insulating layer. The method according to any one of claims 1 to 3, The insulating film is an organic light emitting display device, characterized in that provided with a photoresist. The method according to any one of claims 1 to 3, And wherein the source electrode and the drain electrode, which are electrically connected to the pixel electrode, are integrally provided with the pixel electrode. The method according to any one of claims 1 to 3, And wherein the source electrode and the drain electrode, which are not electrically connected to the pixel electrode, are integrally provided with the first capacitor electrode. The method according to any one of claims 1 to 3, And the second capacitor electrode and the gate electrode are integrally provided.

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