KR20160083641A - Organic electro luminescent device - Google Patents

Abstract

The organic electroluminescent device according to the present invention includes an element substrate on which a plurality of pixel regions are defined, a switching thin film transistor and a driving thin film transistor formed on the pixel region on the element substrate, A diode, an organic thick film layer provided on the organic light emitting diode, and a barrier film adhered to the organic thick film layer, wherein the device substrate and the organic thick film layer are formed to have the same thickness.

Description

[0001] The present invention relates to an organic electroluminescent device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device and a method for manufacturing the same, and more particularly, to a technique for preventing breakage of an inorganic material layer in an organic electroluminescent device.

An organic electroluminescent device, which is one of flat panel displays (FPDs), has high luminance and low operating voltage characteristics. In addition, since it is a self-luminous type that emits light by itself, it has a large contrast ratio, can realize an ultra-thin display, can realize a moving image with a response time of several microseconds (μs), has no viewing angle limit, And it is driven with a low voltage of 5 V to 15 V direct current, so that it is easy to manufacture and design a driving circuit.

Accordingly, the organic electroluminescent device having the above-described advantages has recently been used in various IT devices such as a TV, a monitor, and a mobile phone.

Hereinafter, the basic structure of the organic electroluminescent device will be described in more detail.

1 is a schematic cross-sectional view of a conventional organic electroluminescent device.

The conventional organic electroluminescent device 1 includes an element substrate 10 having an array element (not shown) and an organic electroluminescent diode E and a barrier film 40 for encapsulation, A tempered glass 50 for absorbing external impact may be further formed on the barrier film.

The device substrate 10 is provided with a gate and a data wiring 12 (not shown) for defining a pixel region P intersecting each other and a power source (not shown) spaced apart from any one of these two wirings (Not shown), array elements provided in each pixel region P, and organic light emitting diodes (OLEDs) connected to a part of the array elements and formed in each pixel region P and emitting red, (E) are provided.

The array element (not shown) of the element substrate 10 includes a switching thin film transistor (not shown) connected to a gate and a data line (not shown) 12, and an organic light emitting diode And a driving thin film transistor (not shown) connected thereto.

The organic light emitting diode E includes a first electrode 15 connected to the driving thin film transistor (not shown), an organic light emitting layer 20 and a second electrode 25.

A protective layer 30 of a multilayer or single layer structure made of an inorganic insulating material or an insulating metallic material and an organic insulating material is formed on the second electrode 25.

The protective layer 160 may be formed for the purpose of suppressing moisture and oxygen penetration into the organic electroluminescent device.

On the other hand, an adhesive layer 35 for sealing the organic electroluminescence element is formed corresponding to the element substrate 10 having such a configuration.

The adhesive layer 35 serves to bond the barrier film 40 and the organic electroluminescent diode E to each other.

On the other hand, a plurality of inorganic layers such as a gate insulating film (not shown) and a protective film 30 are formed in a conventional organic light emitting display device.

At this time, when a strong stress such as warpage is applied to a conventional organic electroluminescent device, there is a serious problem that cracks are generated in the many inorganic layers.

In the organic electroluminescent device, an organic thick film layer and an element substrate are formed of resin in order to prevent cracks occurring in the inorganic material layer of the organic electroluminescent device when stress is applied to the organic electroluminescent device .

According to an aspect of the present invention, there is provided an organic electroluminescent device including an element substrate having a plurality of pixel regions defined therein, a switching thin film transistor formed on each pixel region on the element substrate, And an organic light emitting diode connected to the drain electrode of the transistor. The organic thin film layer is formed on the organic light emitting diode and the barrier film is attached to the organic thin film layer. At this time, the organic thick film layer and the element substrate are formed of the same material, and their thicknesses are the same.

According to the present invention, the organic electroluminescent device of the present invention can prevent a crack generated in the inorganic layer by the organic thick film layer and the neutral region between the element substrate when stress is generated in the organic electroluminescent device .

1 is a cross-sectional view schematically showing a conventional organic electroluminescent device.
2 is a cross-sectional view showing a part of an organic electroluminescent device according to an embodiment of the present invention.
3A to 3C are cross-sectional views schematically showing a method of manufacturing an organic electroluminescent device according to an embodiment of the present invention.

Preferred embodiments according to the present invention will be described in detail with reference to the drawings.

2 is a cross-sectional view of a portion of a display region of an organic electroluminescent device according to an embodiment of the present invention. For convenience of description, a region where a switching thin film transistor is to be formed in each pixel region is defined as a switching region, and a region where a driving thin film transistor is to be formed is defined as a driving region DA. A driving thin film transistor DTr is formed in each pixel region P, but only one pixel region P is shown in the drawing.

The organic EL device 101 according to the first embodiment of the present invention includes an element substrate 110 having a driving and switching thin film transistor DTr (not shown) and an organic light emitting diode E, An organic thick film layer 170 for protection and encapsulation of the organic electroluminescent diode E, and a barrier film 190.

At this time, the device substrate 110 and the barrier film 190 are in a state where the organic thick film layer 170 is interposed therebetween.

The organic electroluminescent device of the present invention will be described in more detail. First, an element substrate 110 having a driving and switching thin film transistor (DTr) (not shown) and an organic electroluminescent diode E is formed.

The element substrate 110 is flexible and may be formed of epoxy or acryl resin as a material which can be fired at a low temperature or at a room temperature.

Next, a first region 113a formed of pure polysilicon on the device substrate 110 and having a central portion formed with a channel, and a second region 113a doped with a high concentration of impurities on both sides of the first region 113a A semiconductor layer 113 composed of a semiconductor layer 113b is formed.

A buffer layer 400 made of an inorganic insulating material such as silicon oxide (SiO 2) or silicon nitride (SiN x) may be further formed on the entire surface between the semiconductor layer 113 and the device substrate 110.

The buffer layer 400 prevents the characteristics of the semiconductor layer 113 from deteriorating due to the release of alkali ions from the inside of the device substrate 110 when the semiconductor layer 113 is crystallized.

A gate insulating layer 116 is formed on the entire surface of the device substrate 110 to cover the semiconductor layer 113. The gate insulating layer 116 may be formed of silicon oxide (SiO2) or silicon nitride (SiNx) .

A gate electrode 120 is formed on the gate insulating layer 116 to correspond to the first region 113a of the semiconductor layer 113.

Further, a gate wiring (not shown) connected to the gate electrode (not shown) of the switching thin film transistor (not shown) and extending in one direction is formed.

The gate electrode 120 and the gate wiring (not shown) constituting the driving and switching thin film transistor DTr may be formed of a metal material having low resistance characteristics such as aluminum (Al), aluminum alloy (AlNd), copper (Cu ), A copper alloy, molybdenum (Mo), and molybdenum alloy (MoTi), or a single layer or a multilayer structure.

In addition, an interlayer insulating film 123 is formed on the gate electrode 120 and the gate wiring (not shown).

A semiconductor layer contact hole 125 is formed in the interlayer insulating layer 123 and the gate insulating layer 116 below the interlayer insulating layer 123 to expose each of the second regions 113b located on both sides of the first region 113a .

Next, a data line 130 is formed on the interlayer insulating layer 123 including the semiconductor layer contact hole 125 to define the pixel regions P intersecting the gate lines (not shown).

In addition, a source and a drain, which are respectively in contact with the second region 113b exposed through the semiconductor layer contact hole 125, are spaced apart from each other in the driving region and the switching region DA (not shown) above the interlayer insulating film 123, Drain electrodes 133 and 136 are formed.

A semiconductor layer 113 including the source and drain electrodes 133 and 136 and a second region 113b contacting the electrodes 133 and 136 and a gate electrode The insulating film 116 and the gate electrode 120 constitute a driving thin film transistor DTr and a switching thin film transistor (not shown), respectively.

The source and drain electrodes 133 and 136, which are spaced apart from the data line 130, are also made of a metal material having low resistance characteristics such as aluminum (Al), an aluminum alloy

(AlNd), copper (Cu), a copper alloy, molybdenum (Mo), and molybdenum alloy (MoTi) to form a single layer or a multilayer structure.

The switching thin film transistor (not shown) is electrically connected to the driving thin film transistor DTr, the gate wiring (not shown) and the data wiring 130, and the data wiring 130 is connected to the switching thin film transistor The driving TFT DTr is connected to the power supply line (not shown) and the organic light emitting diode E (not shown).

In the organic electroluminescent device 101 according to the embodiment of the present invention, the driving thin film transistor DTr and the switching thin film transistor (not shown) have a polysilicon semiconductor layer 113 and a top gate type The driving and switching thin film transistor DTr may be a top gate type or a bottom gate type having a semiconductor layer made of an amorphous silicon semiconductor or an oxide semiconductor material .

On the other hand, although not shown, power wiring (not shown) is formed on the same layer on which the gate wiring (not shown) is formed or on the same layer where the data wiring 130 is formed. And is connected to one electrode of the driving thin film transistor DTr.

A protective layer 140 having drain contact holes 143 exposing the drain electrodes 136 of the driving thin film transistor DTr is formed on the driving transistor DTr and the switching thin film transistor have.

At this time, the protective layer 140 may be formed of an organic insulating material, for example, a photoacryl, so as to have a flat surface so as not to be affected by a step of a lower component.

A first electrode 147 is formed on the protective layer 140 having a flat surface to contact the drain electrode 136 of the driving thin film transistor DTr through the drain contact hole 143.

The first electrode 147 may function as an anode or a cathode according to the driving thin film transistor (DTr) type. In the present invention, the first electrode 147 performs an anode function of the organic light emitting diode, and may have a single layer structure of indium-tin-oxide (ITO), which is a transparent conductive material having a large work function value (Al), an aluminum alloy (AlNd), silver (Ag), and APC (Ag; Pb; Cu), which are metal materials having excellent reflectance for increasing the luminous efficiency of the organic light emitting diode A lower layer 147a may be further provided to form a double layer structure of the lower layer 147a and the upper layer 147b.

When the first electrode 147 has a double layer structure, the light emitted from the organic light emitting layer 155 formed on the first electrode 147 is reflected by the lower layer 147a of the first electrode 147, So that the utilization efficiency of the emitted light is increased and finally the luminance characteristic is improved.

In the drawing, the first electrode 147 has a double-layer structure as an example.

Next, the first electrode 147 having the bilayer structure is formed on the boundary of each pixel region P so as to surround each pixel region P, A bank 150 is formed to expose a central portion of the bank 147.

At this time, the bank 150 may be formed of any one of transparent organic insulating materials such as polyimide, photo acryl, and benzocyclobutene (BCB) For example, black resin, but is not limited thereto.

In addition, in the pixel region P surrounded by the bank 150, it is possible to emit light of any one of red (R), green (G) and blue (B) colors on the first electrode (147) Emitting layer 155 is formed.

The organic light emitting layer 155 may further include a material that emits white (not shown) in addition to the light emitting material that emits red (R), green (G), and blue (B) , Green (G), blue (B), and white.

In the drawing, for example, an organic light emitting layer 155 for emitting red (R), green (G), and blue (B) light is formed.

A second electrode 158 is formed on the entire surface of the display region of the organic light emitting layer 155 to serve as a cathode and maintain transparency.

When the first electrode 147 serves as an anode electrode, the second electrode 158 serves as a cathode electrode. As the second electrode 158, a very thin metallic material having a low work function may be used. For example, the second electrode 158 may be formed of a metallic material such as silver (Ag), titanium (Ti), aluminum (Al), molybdenum (Mo), or an alloy of silver (Ag) Can be used. In addition, the metallic materials may be formed to a thickness of several hundreds of angstroms (A) or less, for example, 200 angstroms or less, and used as the second electrode 158. In this case, the second electrode 158 becomes a semi-transparent layer and can be used as a substantially transparent cathode.

Therefore, in an embodiment of the present invention, the top emission system can be used.

At this time, the first and second electrodes 147 and 158 and the organic light emitting layer 155 formed therebetween form an organic light emitting diode (E).

Although not shown in the drawing, the light emitting efficiency of the organic light emitting layer 155 is improved between the first electrode 147 and the organic light emitting layer 155, and between the organic light emitting layer 155 and the second electrode 158, A first emission compensation layer (not shown) and a second emission compensation layer (not shown) having a multi-layer structure may be further formed.

At this time, the first emission compensation layer (not shown) of a plurality of layers is sequentially stacked from the first electrode 147 and may be a hole injection layer and / or a hole transporting layer, The second emission compensation layer (not shown) may include an electron transporting layer and / or an electron injection layer from the organic emission layer 155.

Furthermore, an electron blocking layer may be further provided between the organic emission layer and the first emission compensation layer, and a hole blocking layer may be further formed between the emission layer and the second emission compensation layer. .

Next, a multi-layered or single-layered protective film 160 made of an inorganic insulating material or an insulating metal material and an organic insulating material is formed on the second electrode 158.

The protective layer 160 may be formed for the purpose of suppressing moisture and oxygen penetration into the organic electroluminescent device.

On the other hand, a barrier film 190 for sealing the organic electroluminescence element is formed corresponding to the element substrate 110 having such a configuration.

Meanwhile, the organic electroluminescent device according to an embodiment of the present invention further includes an organic thick film layer 170 between the barrier film 190 and the protective film 160. The organic thick film layer 170 encapsulates the organic electroluminescent device and an adhesive layer (not shown) for bonding the barrier film 190 and the organic thick film layer 170 is formed on the organic thin film layer 170. [ Layer < RTI ID = 0.0 > 170 < / RTI >

At this time, the organic thick film layer 170 is flexible and can be fired at a low temperature or at room temperature and can be formed of an epoxy or acrylic resin.

When stress is generated in the organic electroluminescent device, if the organic thick film layer 170 and the element substrate 110 are formed of the same material or have the same thicknesses h1 and h2, The gate insulating film 116, the interlayer insulating film 123, and the protective film 160 located between the element substrate 110 and the element substrate 110 can be prevented. This is because a neutral zone is formed between the device substrate 110 and the organic thick film layer 170.

On the other hand, when the device substrate 110 and the organic thick film layer 170 are made of the same material and the thicknesses h1 and h2 are the same, the most preferable effect can be obtained.

Therefore, according to one embodiment of the present invention, even when stress is generated in the organic electroluminescent device, cracking of the inorganic layer can be prevented.

3A to 3C are views schematically showing a method of manufacturing an organic electroluminescent device according to an embodiment of the present invention.

In the case of the organic electroluminescent device according to the manufacturing method to be described next, the same components as those of the organic electroluminescent device according to one embodiment of the present invention described above are denoted by the same reference numerals.

Referring to FIG. 3A, an organic electroluminescent device according to an embodiment of the present invention includes a mother substrate 200 and a sacrificial layer 300 formed on the mother substrate 200.

A buffer layer 400 made of silicon oxide (SiO2) or silicon nitride (SiNx) is formed on the sacrificial layer.

Next, the driving thin film transistor, the switching thin film transistor (DTr, not shown), the organic light emitting diode (E), and the protecting layer 160 are sequentially formed.

The organic thick film layer 170 is formed on the protective film 160 by coating or lamination.

The barrier film 190 is formed on the organic thick film layer 170, and an adhesive layer (not shown) may be further formed between the organic thick film layer and the barrier film 190.

Next, referring to FIG. 3B, a laser release process is performed in which the laser is irradiated to the mother substrate 200 to separate the sacrificial layer 300 and the buffer layer 400 in the next step.

At this time, the sacrifice layer 300 may be formed of an amorphous silicon layer (a-si).

Referring to FIG. 3C, after the laser-releasing process, the device substrate 110 is formed on the lower surface of the buffer layer 400 by coating or laminating the device substrate 110 in the same manner as the organic thick film layer.

Meanwhile, the device substrate 110 and the organic thick film layer 170 may be formed of an epoxy or acrylic resin.

In the case of the organic electroluminescent device according to this manufacturing method, even if stress is generated in the organic electroluminescent device, the organic thick film layer 170 and the element substrate 110 are formed of the same material or the same thicknesses h1 and h2 The gate insulating film 116, the interlayer insulating film 123, and the protective film 160, which are located between the device substrate 110 and the organic thick film layer 170, can be prevented . This is because the device substrate 110 and the organic thick film layer 170 form a neutral zone between the two layers 110 and 170.

Although the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be defined by the appended claims and equivalents thereof.

110: element substrate 113: semiconductor layer
120: gate electrode 170: organic thick film layer
190: barrier film

Claims (5)

An element substrate having a plurality of pixel regions defined therein;
A switching thin film transistor and a driving thin film transistor formed in the pixel region on the element substrate;
An organic light emitting diode electrically connected to the driving thin film transistor;
An organic thick film layer provided on the organic light emitting diode;
And a barrier film adhered to the organic thick film layer;
Wherein the device substrate and the organic thick film layer are formed to have the same thickness. The method according to claim 1,
Wherein the device substrate and the organic thick film layer are made of the same material which is flexible and can be fired at a low temperature or at a room temperature. The method according to claim 1,
Wherein the device substrate and the organic thick film layer are formed of an epoxy or acrylic resin. The method according to claim 1,
Wherein a plurality of inorganic film layers are formed on the element substrate. 5. The method of claim 4,
Wherein the inorganic film layer includes a gate insulating film, an interlayer insulating film, and a protective film.

Images