KR20140110497A - Organic electro-luminescent device - Google Patents

Abstract

The present invention provides an organic electro-luminescent device including: a first substrate where a display area having a plurality of pixel areas is defined; a first electrode which is formed at each pixel area and is formed of a transparent conductive material; a reflection transmission pattern which is formed of a metallic material as surrounding each pixel area and being overlapped with an edge of the first electrode, and has reflection characteristics and transmission characteristics by having a first thickness; a bank which is located at a boundary between pixel areas, and is overlapped with a first area of each reflection transmission pattern, and at the same time, exposes a second area in the outside of the first area; an organic light emission layer which is formed on the upper part of the second area exposed to the outside of the first electrode and the bank in an area surrounded by the bank; and a second electrode formed on the whole surface of the display area on the upper part of the organic light emission layer.

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 more particularly, to an organic electroluminescent device including a bank having a dual structure, in which, when forming a liquid organic emission layer, And an organic electroluminescent device capable of suppressing deterioration of lifetime and thus maximizing luminous efficiency.

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.

BACKGROUND ART An organic electroluminescent device is largely composed of an array element and an organic electroluminescent diode. The array element includes a switching thin film transistor connected to a gate and a data line, and a driving thin film transistor connected to the organic light emitting diode. The organic light emitting diode includes a first electrode connected to the driving thin film transistor, Electrode.

In the organic electroluminescent device having such a configuration, light generated from the organic light emitting layer is emitted toward the first electrode or the second electrode to display an image. Considering the aperture ratio and the like, in recent years, And is manufactured by a top emission type in which an image is displayed by using emitted light.

Meanwhile, in the general organic light emitting diode display device, the organic light emitting layer is usually formed by a thermal evaporation method using a shadow mask. In recent years, due to the enlargement of the display device, deflection of the shadow mask is severely generated, It is difficult to manufacture an organic electroluminescent device having a high resolution of 250 PPI or more due to a shadow effect or the like due to thermal evaporation using a shadow mask.

Therefore, a method of forming an organic light emitting layer replacing a thermal deposition process using a shadow mask for manufacturing a large area organic electroluminescent device has been proposed.

The proposed method of forming the organic light emitting layer is to spray or drop a liquid organic light emitting material to a region surrounded by the partition wall through an ink jet apparatus or a nozzle coating apparatus and cure.

1 is a cross-sectional view of an organic electroluminescent device after the step of forming an organic light emitting layer by dropping a liquid organic electroluminescent material through a nozzle coating apparatus.

In order to prevent the organic luminescent material in a liquid state from flowing around in each pixel region P in order to eject liquid organic luminescent material through each of the pixel regions through the inkjet apparatus or to perform dropping through the nozzle coating apparatus A bank is required which surrounds each pixel region P in which the first electrode 50 is formed.

Therefore, as shown in the drawing, the bank 53 having a single layer structure is provided along the boundary of each pixel region P before the organic light emitting layer 55 (Fig. 1B) is provided.

At this time, the bank 53 is made of an organic material having a hydrophobic property. The reason why the bank 53 has the hydrophobic property is that when the liquid organic light emitting material is injected or dropped, the liquid droplets are slightly ejected from the center of the pixel region P surrounded by the bank, Even when a predetermined amount is injected onto the banks 53, the organic EL elements are caused to flow down from the banks 53 to be located in the pixel regions P, and even when the injection amount of the organic luminescent material in the liquid state is slightly increased, It is to suppress the flow.

The organic electroluminescent material is not coated on the upper portion of the bank 53 but concentrated only on the region surrounded by the bank 53 because the organic electroluminescent material has a hydrophobic property It is because.

When the head of the ink jet apparatus or the nozzle of the nozzle coating apparatus 98 is positioned in each pixel region P surrounded by the banks 53 and the liquid organic light emitting material is jetted or dropped, And the organic light emitting layer 55 is formed by drying and curing the organic light emitting layer 55 by progressing the heat treatment in this state.

However, as described above, when the organic light emitting layer 55 is formed through the ink jet device or the nozzle coating device, the edge portions adjacent to the banks 53 are thicker than the central portion in the region surrounded by the respective banks 53 .

This is because the portion in contact with the bank 53 is hardened relatively slowly and the organic light emitting material moves to the edge portion internally as it is hardened from the central portion in the course of curing and finally hardened in this state.

Therefore, the organic light-emitting layer 55 is formed flat in the pixel region P with almost no thickness deviation with respect to the central portion. However, the thickness of the organic light-emitting layer 55 gradually increases toward the edge portion adjacent to the bank 53 Sectional shape.

On the other hand, when the thickness of the organic light emitting layer 55 is different, a difference in luminous efficiency is caused by the application of the same magnitude of current. As a result, the organic light emitting layer 55 has a single- As shown in a photograph of one driven pixel region in an organic electroluminescent device having an organic light emitting layer formed using an organic light emitting material, the organic light emitting layer does not have a flat surface around the bank, And dark portions are darkened. When the user looks at the dark portions, they feel like a smudge. Therefore, the portions that are formed so thick are not visible to the user, so that they do not become a substantial light emitting region.

Referring to FIG. 1, each pixel region P substantially viewed by the user is formed not on the entire surface surrounded by the banks 53 but on the surface of the organic light-emitting layer 55 which has a flat surface, , And the conventional organic electroluminescent device having such a structure has a very low aperture ratio.

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the problems described above, and it is an object of the present invention to improve the aperture ratio by extending a portion having a uniform light emission characteristic in each pixel region by having a flat surface from the region surrounded by the bank to the peripheral portion adjacent to the bank. And to provide an organic electroluminescent device capable of maximizing the luminous efficiency in each pixel region.

According to an aspect of the present invention, there is provided an organic electroluminescent device including a first substrate on which a display region having a plurality of pixel regions is defined; A first electrode formed for each pixel region and made of a transparent conductive material; A reflective transmissive pattern having a reflective property and a transmissive property, the reflective transmissive pattern having a first thickness and being formed of a metal material and superimposed on an edge of the first electrode and surrounding each pixel region; A bank formed at a boundary between the pixel regions and overlapped with the first region of each reflective transmission pattern and exposed to a second region outside the first region; An organic light emitting layer formed on the first electrode and the second region exposed to the outside of the bank in an area surrounded by the bank; And a second electrode formed on the entire surface of the display region above the organic light emitting layer.

At this time, the first thickness is 50 to 500 ANGSTROM, which is thinner than the thickness of the organic light emitting layer.

The reflective transmissive pattern is formed so as to coincide with the side edge of the first electrode or extended to be exposed outside the side edge of the first electrode.

Further, the metallic material is characterized by being aluminum (Al) or an aluminum alloy (AlNd), and the bank has a hydrophobic property.

The organic emission layer is characterized in that the entire region surrounded by the reflective and transmissive pattern has a uniform thickness.

A switching thin film transistor and a driving thin film transistor formed under the first electrode in each of the pixel regions on the first substrate; And a protective layer covering the switching and driving thin film transistor and exposing a drain electrode of the driving thin film transistor, wherein the first electrode is in contact with the drain electrode of the driving thin film transistor in each pixel region on the protection layer .

And a second substrate facing the first substrate, or an encapsulation film which is in contact with the second electrode and serves as the second substrate.

The organic electroluminescent device according to the present invention includes a reflective transmissive pattern having reflection and transmission characteristics along edge portions of a first electrode and a transmissive pattern overlapping a first region of the reflective transmissive pattern, And the reflective transmission pattern has a thickness thinner than the thickness of the organic emission layer so that the organic emission layer is formed on the second region of the reflective transmission pattern exposed to the outside of the bank, .

The organic light emitting layer formed on the reflective / transmissive pattern has a portion having a planarized surface of the same level at the central portion of each pixel region, thereby expanding the area of the flat surface of the organic light emitting layer in each pixel region, Thus, in the entire region surrounded by the transreflective pattern, the organic light emitting layer has a flat surface and has the same thickness.

Therefore, in the organic electroluminescent device according to the embodiment of the present invention having such a configuration, since the light emitting region extends in each pixel region compared with the conventional organic electroluminescent device having the bank having the relatively large width without the reflective transmission pattern, .

Further, since the organic light emitting layer having a flat surface is enlarged in each pixel region, uniform luminance characteristics are obtained, and face defects due to luminance unevenness are suppressed, thereby improving display quality.

Further, since the thickness of the organic light emitting layer is improved by configuring the reflective / transmissive pattern, deterioration of the organic light emitting layer is suppressed and the lifetime is prolonged.

In addition, the generated light can be recycled from the organic light emitting layer in each pixel region by the reflection and transmission pattern, thereby improving light efficiency.

1 is a cross-sectional view of an organic electroluminescent device after the step of forming an organic light emitting layer by dropping a liquid organic light emitting material through a nozzle coating apparatus.
FIG. 2 is a photograph showing one pixel region driven in an organic electroluminescent device having a bank of a single layer structure having a conventional hydrophobic characteristic and forming an organic light emitting layer using a liquid organic electroluminescent material. FIG.
3 is a circuit diagram of one pixel region of an organic electroluminescent device.
4 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.
5 is a sectional view of a driving thin film transistor in an organic electroluminescent device according to a first modification of the embodiment of the present invention.
6 is a sectional view of a driving thin film transistor in an organic electroluminescent device according to a first modification of the embodiment of the present invention.
7 is a cross-sectional view of a portion of a display region of an organic electroluminescent device according to a third modification of the embodiment of the present invention.
8 is a cross-sectional view of a conventional organic electroluminescent device having no reflective / transmissive pattern as a comparative example and an organic electroluminescent device having a reflective transmissive pendant according to an embodiment of the present invention, Respectively.
9 is a view schematically showing progress of light between a reflective transmission pattern and a second electrode in an organic electroluminescent device according to an embodiment of the present invention.
10A to 10K are cross-sectional views illustrating steps of manufacturing an organic electroluminescent device according to an embodiment of the present invention.
11A to 11B are cross-sectional views of a manufacturing process showing a manufacturing method according to a modification of the present invention, showing a step of forming a first electrode and a reflective transmissive region.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, the structure and operation of the organic electroluminescent device will be briefly described with reference to FIG. 3, which is a circuit diagram for one pixel region of the organic electroluminescent device.

A switching thin film transistor STr, a driving thin film transistor DTr, a storage capacitor StgC, and an organic light emitting diode E are formed in each pixel region P of the organic electroluminescent device, .

That is, the gate line GL is formed in the first direction and the data line DL is formed in the second direction intersecting the first direction to form the data line DL surrounded by the gate line GL and the data line DL. And a power supply line PL for applying a power source voltage is formed in the pixel region P spaced apart from the data line DL.

A switching thin film transistor STr is formed at the intersection of the data line DL and the gate line GL and a driving thin film transistor DTr electrically connected to the switching thin film transistor STr is formed have.

The first electrode, which is one terminal of the organic electroluminescent diode E, is connected to the drain electrode of the driving thin film transistor DTr, and the second electrode, which is the other terminal, is grounded. At this time, the power supply voltage transmitted through the power supply line PL is transmitted to the organic light emitting diode E through the driving peak transistor DTr. A storage capacitor StgC is formed between the gate electrode and the source electrode of the driving thin film transistor DTr.

Therefore, when a signal is applied through the gate line GL, the switching thin film transistor STr is turned on and the signal of the data line DL is transmitted to the gate electrode of the driving thin film transistor DTr, The thin film transistor DTr is turned on so that light is output through the organic light emitting diode E.

At this time, when the driving thin film transistor DTr is turned on, the level of a current flowing from the power supply line PL to the organic light emitting diode E is determined, The storage capacitor StgC is capable of maintaining a constant gate voltage of the driving thin film transistor DTr when the switching thin film transistor STr is turned off, The level of the current flowing through the organic light emitting diode E can be kept constant until the next frame even if the switching thin film transistor STr is turned off.

4 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. At this time, although the driving thin film transistor is formed for each pixel region, only one pixel region is shown in the drawing.

The organic EL device 101 according to the embodiment of the present invention includes a first substrate 110 on which a driving and switching thin film transistor DTr (not shown) and an organic light emitting diode E are formed, And a second substrate 170 for encapsulation. At this time, the second substrate 170 may be omitted by being replaced with an inorganic insulating film, an organic insulating film, or the like.

First, the structure of the first substrate 110 including the driving and switching thin film transistor DTr (not shown) and the organic electroluminescent diode E will be described.

A gate line (not shown) and a data line 130 are formed on the first substrate 110. The gate line and the data line 130 intersect each other with a gate insulating layer interposed therebetween, A power wiring (not shown) is formed in parallel with the gate wiring (not shown) or the data wiring 130.

A plurality of pixel regions P are connected to the gate wiring (not shown) and the data wiring 130 and are formed with switching thin film transistors (not shown). A switching thin film transistor (not shown) And a driving thin film transistor DTr connected to the power supply line (not shown).

At this time, the driving thin film transistor DTr includes a polysilicon semiconductor layer 113a including an active region 113a made of pure polysilicon and a source and drain region 113b made of polysilicon doped with impurities on both sides of the active region 113a And a semiconductor layer contact hole (125) exposing the source and drain regions (113b), a gate electrode (120) formed over the active region (113a) And source and drain electrodes 133 and 136 formed in contact with the source and drain regions 113b through the semiconductor layer contact holes 125 and spaced apart from each other. The switching thin film transistor (not shown) also has the same structure as the driving thin film transistor DTr.

In the embodiment of the present invention, the driving and switching thin film transistors DTr (not shown) each include the semiconductor layer 113 of polysilicon, , The configuration of the driving and switching thin film transistor DTr (not shown) may be variously modified.

That is, as shown in FIG. 5 (sectional view of the driving thin film transistor in the organic EL device according to the first modification of the embodiment of the present invention), the switching and driving thin film transistor (not shown, DTr) A semiconductor layer 220 composed of a gate insulating film 218, an active layer 220a of pure amorphous silicon and an ohmic contact layer 220b of an impurity amorphous silicon and a semiconductor layer 220 formed on the semiconductor layer 220, And source and drain electrodes 233 and 236, respectively.

6, the switching and driving thin film transistor (not shown, DTr) is connected to the gate electrode of the organic EL element according to the second embodiment of the present invention, The oxide semiconductor layer 320, the etch stopper 322, and the etch stopper 322, which are spaced apart from each other on the electrode 315, the gate insulating film 318, the oxide semiconductor layer 320, the oxide semiconductor layer 320, An electrode 333, and a drain electrode 336, as shown in FIG.

In the first and second embodiments, the switching and driving thin film transistor DTr (not shown) includes a gate electrode (213 in FIG. 5, 315 in FIG. 6) Structure.

5), and the data line (not shown) is located under the gate insulating film 218 (FIG. 5, 318) and the gate line (not shown) As shown in FIG.

4, a protective layer 140 (not shown) having a drain contact hole 143 exposing a drain electrode 136 of the driving thin film transistor DTr is formed on the driving and switching thin film transistor DTr Is formed.

At this time, the passivation layer 140 is formed of an organic insulating material, for example, a photo acryl so as to form a flat surface.

Next, the pixel region P contacts the drain electrode 136 of the driving thin film transistor DTr through the drain contact hole 143 on the passivation layer 140 having the drain contact hole 143, The first electrode 150 is formed.

The first electrode 150 is made of a transparent conductive material having a work function value of about 4.8 eV to about 5.2 eV, for example, indium-tin-oxide (ITO) .

In the organic electroluminescent device 101 according to the embodiment of the present invention (or the first and second modifications), the first electrode 150 made of the transparent conductive material is provided on each pixel region For example, aluminum (Al) or an aluminum alloy (AlNd) having excellent reflection characteristics corresponding to a predetermined width of the edge portion of each of the first electrodes 150 .

At this time, the transreflective pattern 152 has a thickness of about 50 to 500 ANGSTROM, so that the transreflective pattern 152 has a characteristic of transmitting light in addition to the function of bending light.

When the reflective transmission pattern 152 having reflection characteristics and transmission characteristics along the rim of the first electrode 150 provided in each pixel region P has a thickness of about 50 to 500 Å, The first electrode 160 and the second electrode 160 form a structure in which light is reflected between the two components 152 and 160 and the second electrode 160 and the reflection / The light incident on the reflective transmissive pattern 152 at a specific angle that overcomes the total internal reflection condition is transmitted through the first substrate 110 and emitted toward the first substrate 110, thereby improving the light efficiency.

At this time, in addition to the boundaries between neighboring pixel regions P in the neighboring pixel regions P, the sum of the widths of the reflective transmissive patterns 152 located on both sides of the pixel regions P Is a width of a bank (53 in Fig. 1) provided in a conventional organic electroluminescence device (see Fig. 1).

On the other hand, as a third modification according to the embodiment of the present invention, a cross-sectional view of a driving thin film transistor in Fig. 7 (a cross-sectional view of a portion of a display region of an organic electroluminescent device according to a third modification of the embodiment of the present invention) One end of the reflective transmission pattern 152 is formed to extend to the boundary of each pixel region P outside the first electrode 150 without being coincident with the side edge of the first electrode 150 .

Next, polyimide, styrene, and polyimide containing a high molecular substance having hydrophobic property, for example, fluorine (F), are formed on the boundary of each pixel region P, A bank 153 having a second width smaller than the first width is formed of a material in which one or more of methyl mathacrylate and polytetrafluoroethylene are mixed.

Therefore, the organic light emitting device according to the embodiment of the present invention has the above-described structure of the bank 153, which is formed by exposing the reflective transmissive pattern 152 to the outside of the bank 153 by a predetermined width .

The organic electroluminescent device 101 according to the embodiment of the present invention is provided with the reflective transmission pattern 152 and the bank 153 having the second width smaller than the first width, An organic light emitting layer 155 is formed on a portion of the pattern 152 that is not covered by the bank 153. The reflective transmission pattern 152 is formed along the rim of each pixel region P, In order to form the light emitting layer 155, the organic light emitting material is collected at the central portion of each pixel region P when the organic light emitting material is dropped, so that a portion adjacent to the bank 153, that is, And the thickness of the organic light emitting layer 155 located in the pixel region P becomes thicker than the center of each pixel region P. [

Furthermore, in the pixel region, the region surrounded by the reflective / transmissive pattern 152 has substantially the same size as the region surrounded by the banks 153 in the conventional organic electroluminescent device, The width of the boundary between the pixel regions P located between the two reflective transmission patterns 152 including the width of the banks provided in the organic electroluminescent device or the widths of two neighboring reflective transmission patterns 152 The area enclosed by the bank 153 having the second width smaller than the width of the bank (the sum of the widths of the banks) is larger than the area surrounded by the banks (53 in Fig. 1) in the conventional organic electroluminescent device .

The reflective transmissive pattern 152 may be formed to have a thickness smaller than the thickness of the organic light emitting layer 155. The reflective transmissive pattern 152 may be formed on the reflective reflective pattern 152 exposed outside the bank 153, And an organic light emitting layer 155 is formed thereon.

In addition, the organic light emitting layer 155 formed on the reflective transmission pattern 152 has a portion having the same level of planarized surface at the center of each pixel region P, The organic light emitting layer 155 formed on the entire region surrounded by the transmissive transmissive pattern 152 has a flat surface and has the same thickness.

Therefore, when it is assumed that a region where the organic light emitting layer 155 forms a flat portion in each pixel region P is a light emitting region EA2 that is substantially viewed by the user, the organic light emitting layer 155 according to the embodiment of the present invention 1) with respect to a conventional organic electroluminescent element (see FIG. 1) provided with a bank (53 in FIG. 1) in contact with the first electrode (50 in FIG. 1) EA1 of EA1) is expanded, so that the aperture ratio is improved.

 8 is a cross-sectional view of a conventional organic electroluminescent device having no reflective / transmissive pattern as a comparative example and an organic electroluminescent device having a reflective / transmissive pattern according to an embodiment of the present invention, Respectively.

As shown in the figure, when a pixel region of the same size is formed, the pixel region is defined as a region substantially captured by a gate wiring (not shown) and a data wiring 30 and 130. However, Assuming that a region surrounded by the reflective transmission pattern 152 is a new pixel region SP in the organic electroluminescent device according to the embodiment of the present invention, in the case of the comparative example, the region surrounded by the bank 53 is the pixel region SP do.

In this case, it can be seen that the two organic electroluminescent devices 1 and 101 have the pixel region SP of the same size.

However, the sizes of the emission regions EA1 and EA2 in each pixel region SP are larger than those of the conventional organic electroluminescent element 1 according to the embodiment of the present invention (EA1 ≪ EA2).

In the conventional organic electroluminescent device 1 having the bank 53 having the first width without the reflective / transmissive pattern according to the comparative example, the entire surface of the pixel region SP surrounded by the bank 53 does not become the light emitting region And the portion of the organic EL device 53, which has a predetermined width, that is, the surface of the organic electroluminescent device 53, which is flat on the basis of the bank 53, becomes the light emitting region EA1.

Therefore, in the conventional organic electroluminescent device 1 without the reflective / transmissive pattern according to the comparative example, a light emitting area EA1 having an area smaller than that of the pixel area P is formed in the pixel area P.

However, the organic electroluminescent device 101 according to the embodiment of the present invention includes a region surrounded by the reflective transmissive pattern 152 and a region surrounded by the bank 153, and a region surrounded by the reflective transmissive pattern 152 is a conventional The area surrounded by the bank 153 having the second width corresponds to the pixel area SP of the organic electroluminescent device of the conventional pixel area SP.

In the organic electroluminescent device 101 according to the embodiment of the present invention having such a structure, the organic light emitting layer 155 having a flat surface corresponding to the entire area surrounded by the transreflective pattern 152 is formed, The entire area surrounded by the pattern 152 becomes the light emitting area EA2.

Therefore, the organic electroluminescent device 101 according to the embodiment of the present invention expands the light emitting region EA2 in each pixel region SP with respect to the conventional organic electroluminescent device 1, thereby improving the aperture ratio It can be seen that the

Referring to FIG. 9 (a view schematically showing the progress of light between the reflective transmissive pattern and the second electrode in the organic EL device according to the embodiment of the present invention), the reflective transmissive pattern 152 itself Reflection and transmission are performed according to the angle of incidence of light so that a part of the light reflected through the second electrode 160 is reflected again and the other part is transmitted in a direction in which the protective layer 140 is located The light efficiency is further improved by inducing the recycling of the light generated from the organic light emitting layer 155.

4, the organic electroluminescent device 101 according to the embodiment of the present invention having such a structure is formed in a region surrounded by the banks 153, And an organic light emitting layer 155 is formed on the first electrode 150 and the organic light emitting layer 155.

At this time, the organic light emitting layer 155 is formed of materials that emit red, green, and blue light, respectively, in a repetitive manner with respect to each pixel region P.

The organic light emitting layer 155 is formed by spraying or dropping a liquid organic light emitting material through an ink jet apparatus or a nozzle coating apparatus, and then curing the organic light emitting layer 155.

Although the organic light emitting layer 155 is shown as a single layer composed only of an organic light emitting material in the drawing, the organic light emitting layer 155 may have a multi-layer structure to enhance the light emitting efficiency.

In the case where the organic emission layer 155 has a multilayer structure, a hole injection layer, a hole transport layer (hole injection layer), and a hole transport layer (hole transport layer) are sequentially formed from the top of the first electrode 150 serving as the anode electrode layer structure of a hole transporting layer, an electron transporting layer, and an electron injection layer, or a hole transporting layer, an organic electroluminescent layer, Layer structure of an emitting material layer, an electron transporting layer and an electron injection layer, a hole transporting layer, an emitting material layer, an electron transporting layer, (electron transporting layer).

In addition, a second electrode 160 is formed on the entire surface of the display region on the organic light emitting layer 155. The second electrode 160 may be formed of a metal material having a relatively low work function value such as aluminum (Al), aluminum alloy (AlNd), silver (Ag), magnesium (Mg), gold (Au), aluminum magnesium alloy (AlMg), and serves as a cathode electrode.

At this time, the first electrode 150, the organic light emitting layer 155, and the second electrode 160, which are sequentially stacked on the first substrate 110, constitute an organic light emitting diode E.

Meanwhile, a second substrate 170 for encapsulation is provided corresponding to the first substrate 110 of the organic electroluminescent device 101 according to the embodiment of the present invention.

The first substrate 110 and the second substrate 170 are provided with an adhesive agent (not shown) made of a sealant or a frit along the edge thereof. The adhesive agent (not shown) 110 and the second substrate 170 are adhered to each other to maintain the panel state.

At this time, a vacuum state is formed between the first substrate 110 and the second substrate 170 which are spaced apart from each other, or an inert gas atmosphere may be obtained by being filled with an inert gas.

The second substrate 170 for the encapsulation may be made of plastic having a flexible property, or may be made of a glass substrate.

Meanwhile, although the organic EL device 101 according to the above-described embodiment includes the second substrate 170 for encapsulation in a form spaced apart from the first substrate 110, The second substrate 170 may be in contact with the second electrode 160 provided on the uppermost layer of the first substrate 110 in the form of a film including an adhesive layer.

Further, as another modification of the embodiment of the present invention, an organic insulating film (not shown) or an inorganic insulating film (not shown) may further be provided on the second electrode 160 to form a capping film, (Not shown) or the inorganic insulating film 162 may be used as an encapsulation film (not shown) by itself. In this case, the second substrate 170 may be omitted.

The organic electroluminescent device 101 according to the present invention having the above-described structure includes a reflective transmissive pattern 152 having reflection and transmission characteristics along the edges of the first electrode 150, The bank 153b is formed of a material having a hydrophobic property such that a part of the reflective transmission pattern 152 is overlapped with a part of the reflective layer 152. Further, The organic light emitting layer 155 is formed on the reflective transmissive pattern 152 exposed to the outside of the bank.

At this time, the organic light emitting layer 155 formed on the reflective transmission pattern 152 has a portion having a planarized surface at the same level at the center of each pixel region P, The organic light emitting layer 155 has a flat surface and has the same thickness in the entire region surrounded by the transmissive transmissive pattern 152. As a result,

Therefore, the organic electroluminescent device according to the embodiment of the present invention having such a configuration is a conventional organic electroluminescent device having the banks (53 in FIG. 1) having a relatively large width without the reflective transmission pattern 152 The light emitting region is enlarged in each pixel region P, thereby improving the aperture ratio.

Further, since the organic light emitting layer 155 having a flat surface in each pixel region P is enlarged, uniform luminance characteristics are obtained, so that a face defect due to luminance unevenness is suppressed, and the display quality is improved.

The thickness of the organic light emitting layer 155 is improved by the provision of the transreflective pattern 152 so that deterioration of the organic light emitting layer 155 is suppressed and the lifetime is prolonged. The generated light can be recycled from the organic light emitting layer 155 in each pixel region P, thereby improving light efficiency.

Hereinafter, a method of manufacturing an organic electroluminescent device according to an embodiment of the present invention having the above-described structure will be described. The organic electroluminescent device according to an embodiment of the present invention is characterized in that the first electrode and the reflective transmissive pattern formed to overlap with the edge of the first electrode, and the bank formed by exposing the reflective transmissive pattern, Since the step of forming the transistor is manufactured by a general method, a description thereof will be briefly described, and a step of forming the reflective transmission pattern will be described in detail.

10A to 10K are cross-sectional views illustrating the steps of manufacturing an organic electroluminescent device according to an embodiment of the present invention.

First, as shown in FIG. 10A, gate wirings (not shown) and date wirings (not shown) intersecting each other by a general method on a first substrate 110 made of a transparent material, A switching thin film transistor (not shown) connected to the gate and the data line (not shown) is formed in a switching region (not shown), and at the same time, Thereby forming a driving thin film transistor DTr connected to the switching thin film transistor (not shown) and power supply wiring (not shown).

In this case, the switching and driving thin film transistor (not shown) DTr includes a semiconductor layer 120 of polysilicon so that the semiconductor layer 120 of polysilicon is formed on the lowest surface of the first substrate 110 5) and the ohmic contact layer 220b (FIG. 5) of the impurity amorphous silicon, as in the modification (see FIGS. 5 and 6) (220 in FIG. 5) or an oxide semiconductor layer (120 in FIG. 6) on the first substrate (210 in FIG. 5, 310 in FIG. 6) , 315 in Fig. 6) are provided on the lowest surface.

In the drawing, for example, the switching and driving thin film transistors (not shown) are formed in a top gate type including a semiconductor layer 120 of polysilicon.

Next, a protective layer 140 having a flat surface is formed by applying an organic insulating material, for example, photoacrylic, on the switching and driving thin film transistor (not shown) (DTr), and a mask process is performed on the protective layer 140, A drain contact hole 143 exposing the drain electrode 136 of the thin film transistor DTr is formed.

Next, as shown in FIG. 10B, a transparent conductive material such as indium-tin-oxide (ITO) having a relatively large work function value is deposited on the passivation layer 140 having the drain contact hole 143 A transparent conductive material layer 145 is formed and aluminum (Al) or aluminum alloy (AlNd), which is a metal material having excellent reflectance, is deposited to have a thickness of about 50 to 500 Å, Thereby forming the transmissive layer 146.

Thereafter, a photoresist, which is a photosensitive material, is applied on the transflective layer 146 to form a photoresist layer (not shown).

Then, an exposure mask (not shown) having a transmissive area and a blocking area on the photoresist layer (not shown) and a semi-transmissive area such as a slit area or a halftone area having a light transmission amount smaller than the transmissive area and larger than the blocking area A first photoresist pattern 190a having a first thickness is formed by exposing the exposed photoresist layer (not shown), and developing the exposed photoresist layer (not shown) A second photoresist pattern 190b having a second thickness smaller than the first thickness is formed.

At this time, the first photoresist pattern 190a is formed corresponding to a portion where a later reflection and transmission pattern (152 of FIG. 10K) is to be formed, and the second photoresist pattern 190b is formed later on the first electrode The first electrode 150 is formed so as to correspond to a portion where the scarlet reflection transmission pattern (152 of FIG. 10K) is not formed and the boundary between the pixel regions P is formed The photoresist layer (not shown) is removed.

Next, as shown in FIG. 10C, using the first and second photoresist patterns 190a and 190b as an etching-resistant mask, the transparent conductive material layer 146 (shown in FIG. 10B) (145 in FIG. 10B) is removed, an electrode pattern 147 having a double-layer structure of a transparent conductive material and a metal material is formed in each pixel region P in the present state.

Then, as shown in FIG. 10D, ashing is performed to expose a part of the electrode pattern 147 by removing the second photoresist pattern 190b (FIG. 10C).

At this time, the first photoresist pattern 190a is partially reduced in thickness by the ashing, but remains on the electrode pattern 147. [

Next, as shown in FIG. 10E, an upper layer made of a metal material is removed from the electrode pattern 147 (shown in FIG. 10C) exposed to the outside of the first photoresist pattern 190b, And a first electrode 150 is formed to contact the drain electrode 136 of the driving thin film transistor DTr through each drain contact hole 143. [

At the same time, a reflective transmissive pattern 152 is formed, which overlaps the predetermined width of the edge portion of each of the first electrodes 150 in a form of framing the first electrodes 150.

Next, as shown in FIG. 10F, the strip is advanced to remove the first photoresist pattern (190a in FIG. 10E).

Meanwhile, in the method of manufacturing an organic electroluminescent device according to an embodiment of the present invention, the first electrode 150 and the reflective and transmissive pattern 152 are formed in a single mask (not shown) using an exposure mask The method of forming the first electrode 150 and the reflective and transmissive pattern 152 may be variously modified.

FIGS. 11A and 11B are cross-sectional views illustrating a manufacturing method according to a modification of the present invention, illustrating steps of forming a first electrode and a reflective transmissive region.

As shown in FIG. 11A, a transparent conductive material layer (not shown) is formed on the protective layer 140 and exposed to light using an exposure mask (not shown) The first electrode 150 is preferentially formed by the progress of the masking process.

Then, as shown in FIG. 11B, a reflective material (not shown) is deposited on the first electrode 150 to have a thickness of about 50 to 500 ANGSTROM to form a reflective material A masking process may be performed one time to form a reflective transmissive pattern 152 having a predetermined width of each of the first electrodes 150.

When the first electrode 150 and the reflective transmission pattern 152 are formed by the two mask processes, the side ends of the first electrode 150 and the reflective transmission pattern 152 do not coincide with each other, The reflective transmissive pattern 152 extending to the boundary of each pixel region P is formed outside the one electrode 150.

Since the reflective transmissive pattern 152 is in contact with the first electrode 152 provided in each pixel region P, the reflective transmissive pattern 152 may extend to the boundary of the neighboring pixel regions P, The reflective transmissive patterns 152 are spaced apart from each other without being contacted with each other.

When neighboring reflective transmission patterns 152 are in contact with each other, short-circuiting occurs between neighboring first electrodes 150 to prevent this.

Next, as shown in FIG. 10G, the protective layer 140 and the first electrode 150, which are exposed between the boundaries of the pixel regions P, that is, the spacing between adjacent first electrodes 150, For example, polyimide containing fluorine (F), styrene (styrene), or the like, which has a photosensitive property on the entire surface of the reflective transmissive pattern 152 formed on the reflective transmissive pattern 152, A bank material layer (not shown) is formed by applying a mixture of one or more of the above materials (e.g., polytetrafluoroethylene), methyl mathacrylate, and polytetrafluoroethylene.

In this case, the polymer material forming the bank material layer (not shown) has a photosensitive characteristic of a negative type in which a light-receiving portion is left after development. However, in the case of a positive type photosensitive material Property.

An exposure mask (not shown) having a general light transmission region and a blocking region is disposed on the bank material layer (not shown) having such a negative type photosensitive property, and the exposure mask (Not shown), and development of the exposed bank material layer (not shown) exposes the boundary of the pixel region P with the boundary of the reflective transmissive pattern 152 located in each pixel region P The banks 153 overlapping the first regions corresponding to some predetermined widths and exposing the second regions corresponding to some of the predetermined widths are formed.

10H, a liquid organic light emitting material is supplied to the bank 153b using an inkjet apparatus or a nozzle coating apparatus 199 corresponding to the first substrate 110 on which the banks 153 are formed, The organic light emitting material layer 154 is formed on the first electrode 150 and on the reflective transmission pattern 152 exposed to the outside of the bank 153 by spraying or dropping corresponding to the region surrounded by the first electrode 150 and the bank 153.

When the liquid organic light emitting material is injected or dropped into each pixel region P in the step of injecting or dropping the liquid organic light emitting material, the ink jet apparatus (not shown) or the nozzle coating apparatus 199 The bank 153 has a hydrophobic property and flows into each pixel region P even if the injection or dropping position of the bank 153 is deviated due to its own error.

Also, even if the injection amount of the organic luminescent material in the liquid phase is a little, the bank 153 has a hydrophobic characteristic, so that it tends to push out the organic luminescent material, thereby preventing overflow.

Further, since the reflective transmissive pattern 152 has a thickness smaller than the thickness of the organic light emitting material layer 154, the organic light emitting material layer 154 is formed to the upper portion of the reflective transmissive pattern 152.

In this state, as shown in FIG. 10I, the organic light emitting material layer (154 in FIG. 9H) is subjected to a drying and curing process to remove solvent and moisture, thereby forming a cured organic light emitting layer (155) can be formed.

Meanwhile, the organic light emitting material layer 154 (shown in FIG. 10H) formed on the reflective transmissive pattern 152 in each pixel region P is formed in the step of forming the organic light emitting layer 155 by progressing the curing process. The planar surface state of the organic light emitting layer 155 in the pixel region P is maintained to be the same as that of the organic light emitting layer 155 formed in the central portion of the pixel region P, To the upper portion of the display screen.

In this case, the organic light emitting layer 155 has a flat surface from a central portion of each pixel region P up to a part of the reflective transmissive pattern 152 to form a light emitting region up to the side edge of the reflective transmissive pattern 152 The same luminance characteristics are obtained.

Therefore, the organic electroluminescent device according to the embodiment of the present invention is characterized in that the light emitting region (EA2 in FIG. 8) in each pixel region P is formed by a conventional organic It has an effect of expanding compared to the electroluminescent element (1 in Fig. 8).

In addition, the light generated in the organic light emitting layer 155 is recycled at the portion where the reflective / transmissive pattern 152 is formed, so that the organic light emitting device according to the embodiment of the present invention has an effect of improving the light efficiency.

Although an organic light emitting layer 155 having a single layer structure is formed on the first electrode 150 and the transmissive transmissive pattern 152 in the drawing, the organic light emitting layer 155 may be formed of multiple layers In this case, the same method as that for forming the single-layer organic light-emitting layer 155 is performed, or a method for performing front-surface deposition in the display region is performed to form a hole injection hole or hole at least one of an electron injection layer (not shown), a hole transporting layer (not shown), an electron transporting layer (not shown), and an electron injection layer (not shown) Can be further formed.

Next, as shown in FIG. 10J, a metal material having a relatively low work function value such as aluminum (Al), an aluminum alloy (AlNd), silver (Ag), magnesium (Mg) (Au), aluminum magnesium alloy (AlMg), or the like is deposited on the entire surface of the display region to form the second electrode 160. As a result, the organic electroluminescent device according to the embodiment of the present invention and modifications thereof The first substrate 110 is completed.

The first electrode 150, the organic light emitting layer 155, and the second electrode 160, which are sequentially stacked in each pixel region P, form the organic light emitting diode E by the above-described method.

Next, as shown in FIG. 10K, the second substrate 170 is opposed to the first substrate 110 in order to encapsulate the organic light emitting diode E in correspondence with the first substrate 110, A face seal (not shown) made of a frit, an organic insulating material, or a polymer material having a transparent and adhesive property is formed between the first substrate 110 and the second substrate 170 on the front surface of the first substrate 110 The first substrate 110 and the second substrate 170 are attached to each other in a coated state or a seal pattern (not shown) is formed along the edge of the first substrate 110 in a vacuum or inert gas atmosphere The first and second substrates 110 and 170 are bonded together to complete an organic light emitting device according to an embodiment of the present invention.

An inorganic insulating material or an organic insulating material is deposited or coated on the second electrode 160 of the first substrate 110 or an adhesive layer (not shown) is resumed to attach a film (not shown) When used as an encapsulation film (not shown), the second substrate 170 may be omitted.

The present invention is not limited to the above-described embodiments and modifications, and various modifications may be made without departing from the spirit of the present invention.

101: organic electroluminescent device 110: first substrate
115: gate electrode 118: gate insulating film
120: oxide semiconductor layer 122: etch stopper
133: source electrode 136: drain electrode
140: protective layer 143: drain contact hole
150: first electrode 152: reflection / transmission pattern
153: bank 155: organic light emitting layer
160: second electrode 170: second substrate
DTr: driving thin film transistor P: pixel region

Claims (8)

A first substrate on which a display region having a plurality of pixel regions is defined;
A first electrode formed for each pixel region and made of a transparent conductive material;
A reflective transmissive pattern having a reflective property and a transmissive property, the reflective transmissive pattern having a first thickness and being formed of a metal material and superimposed on an edge of the first electrode and surrounding each pixel region;
A bank formed at a boundary between the pixel regions and overlapped with the first region of each reflective transmission pattern and exposed to a second region outside the first region;
An organic light emitting layer formed on the first electrode and the second region exposed to the outside of the bank in an area surrounded by the bank;
A second electrode formed on the entire surface of the display region,
And an organic electroluminescent device.
The method according to claim 1,
Wherein the first thickness is 50 to 500 ANGSTROM and is thinner than the thickness of the organic light emitting layer.
The method according to claim 1,
Wherein the reflective transmissive pattern is formed so as to coincide with the side of the first electrode or extended to be exposed outside the side edge of the first electrode.
The method according to claim 1,
Wherein the metal material is aluminum (Al) or an aluminum alloy (AlNd).
The method according to claim 1,
Wherein the bank has a hydrophobic property.
The method according to claim 1,
Wherein the organic light emitting layer has a uniform thickness over the entire region surrounded by the reflective and transmissive pattern.
The method according to claim 1,
A switching thin film transistor and a driving thin film transistor formed under the first electrode in each pixel region on the first substrate;
And a protective layer covering the switching and driving thin film transistor and exposing a drain electrode of the driving thin film transistor,
Wherein the first electrode is formed in contact with the drain electrode of the driving thin film transistor in the pixel region over the protective layer.
The method according to claim 1,
A second substrate facing the first substrate, or an encapsulation film which is in contact with the second electrode and serves as the second substrate.

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