KR102505167B1 - Organic light emitting diodes - Google Patents

Abstract

The present invention relates to an OLED, and more particularly to an OLED having improved light extraction efficiency.
A feature of the present invention is that the bank of the OLED is made of a metal having reflectivity, and the bank is formed to surround the end of the first electrode.
Through this, the light extraction efficiency of the OLED is improved to improve the luminance of the OLED, and since the driving voltage of the OLED does not have to be increased to increase the luminance of the OLED, the deterioration of the organic light emitting layer due to the increase in the driving voltage is prevented. can be prevented from occurring, and through this, it is possible to prevent shortening of the lifetime of the OLED.

Description

Organic light emitting diodes {Organic light emitting diodes}

The present invention relates to an OLED, and more particularly to an OLED having improved light extraction efficiency.

BACKGROUND OF THE INVENTION [0002] In recent years, as society has entered an information age in earnest, the display field for processing and displaying a large amount of information has developed rapidly, and in response to this, various flat panel display devices have been developed and are in the spotlight.

Specific examples of such a flat panel display device include a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), and an electric light emitting display device. (Electroluminescence Display device: ELD) and organic light emitting diodes (OLED), etc. ) is rapidly replacing

Among the above flat panel display devices, an organic light emitting device (hereinafter, referred to as OLED) is a self-emitting device and can be lightweight and thin because it does not require a backlight used in a liquid crystal display device, which is a non-light emitting device.

In addition, it has excellent viewing angle and contrast ratio compared to liquid crystal displays, is advantageous in terms of power consumption, can be driven at low DC voltage, has a fast response speed, is resistant to external shocks because the internal components are solid, and has a wide operating temperature range. It has advantages.

These OLEDs are composed of a hole injection electrode, an organic light emitting layer, and an electron injection electrode, and light is emitted by the energy generated when excitons generated by combining electrons and holes inside the organic light emitting layer fall from an excited state to a ground state. .

Here, when light is emitted at a critical angle or higher, the light causes total internal reflection at an interface between a transparent electrode having a high refractive index and a substrate having a low refractive index. Due to this total reflection, substantially about 1/4 of the light formed in the organic light emitting layer is emitted to the outside. Accordingly, the OLED has a problem in that optical properties, that is, light efficiency are lowered.

In addition, when the light efficiency is lowered, the luminance of the OLED is lowered, and in order to increase the luminance of the OLED, the driving voltage of the OLED must be increased. problems that may arise.

The present invention is to solve the above problems, and a first object is to provide an organic light emitting device having improved light efficiency.

Through this, the second object is to improve the luminance of the organic light emitting device, and the third object is to prevent the problem of shortening the lifetime of the organic light emitting device due to deterioration of the organic light emitting layer.

In order to achieve the object as described above, the present invention provides a first substrate in which a plurality of pixel areas are defined, a first electrode provided for each pixel area, and an edge of the first electrode surrounding each pixel area. A first bank overlapping with and made of a metal material having a reflectance, an insulating layer interposed between the first bank and the first electrode, and an organic layer positioned above the first electrode in a region surrounded by the first bank An organic light emitting device including a light emitting layer and a second electrode positioned above the organic light emitting layer is provided.

As described above, according to the present invention, the bank of the OLED is made of a metal having reflectance, and the bank is formed to surround the end of the first electrode, thereby improving the light extraction efficiency of the OLED.

Through this, there is an effect of improving the luminance of the OLED, and since it is not necessary to increase the driving voltage of the OLED to increase the luminance of the OLED, it is possible to prevent the deterioration of the organic light emitting layer due to the increase in the driving voltage from occurring. There is an effect that there is, and through this, there is an effect that can prevent the life span of the OLED from being shortened.

1 is a cross-sectional view schematically showing a cross-section of an OLED according to an embodiment of the present invention.
2 is a view for explaining a mechanism for improving light extraction efficiency of an OLED according to a first embodiment of the present invention.
3a to 3b are simulation results obtained by comparing and measuring the light efficiency and color characteristics of an OLED according to a first embodiment of the present invention and a typical OLED.
4 is a view for explaining a mechanism for improving the light extraction efficiency of an OLED according to a second embodiment of the present invention.
5 is a view for explaining a mechanism for improving light extraction efficiency of an OLED according to a third embodiment of the present invention.

The present invention includes a first substrate in which a plurality of pixel areas are defined, a first electrode provided for each pixel area, and a metal material that surrounds each pixel area and overlaps the edge of the first electrode and has a reflectance. An insulating layer interposed between the first bank and the first electrode, an organic light emitting layer positioned above the first electrode in a region surrounded by the first bank, and an organic light emitting layer positioned above the organic light emitting layer. An organic light emitting device including a second electrode is provided.

In this case, the insulating layer has the same optical refractive index as the first electrode, and the insulating layer has the same area and shape as the first bank.

The insulating layer is made of one of silicon nitride (SiNx) and silicon oxide (SiOx), and the first bank is made of silver (Ag), chromium (Cr), aluminum (Al), molybdenum (Mo), gold (Au) ), made of at least one selected from titanium (Ti) and magnesium (Mg).

In addition, a second bank having a hydrophobic property is located above the first bank, and the first bank, the insulating layer, and the second bank have the same area and shape, and each pixel area on the first substrate a driving thin film transistor formed under the first electrode, and a protective layer formed covering the driving thin film transistor and exposing a drain electrode of the driving thin film transistor, wherein the first electrode is formed on the protective layer and within each pixel area. It is formed in contact with the drain electrode of the driving thin film transistor.

In addition, a second substrate facing the first substrate is provided, or an encapsulation film that contacts the second electrode and serves as the second substrate is provided.

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

1 is a cross-sectional view schematically showing a cross-section of an OLED according to an embodiment of the present invention.

In this case, the driving thin film transistor DTr is formed for each pixel region P, but in the drawings, only one pixel region P is shown for convenience of description.

And, for convenience of description, an area that actually implements an image is defined as an emission area (EA), and an area where the driving thin film transistor (DTr) and various wires are formed is defined as a non-emission area (NEA).

Prior to the description, the OLED 100 is divided into a top emission type and a bottom emission type according to the transmission direction of the emitted light. The bottom emission type has high stability and freedom in processing. , Research on the bottom light emission method is being actively conducted. Hereinafter, the OLED 100 of the present invention is a bottom emission method.

As shown, the OLED 100 according to the present invention is an OLED 100 formed by spraying or applying a liquid organic light emitting material to the area surrounded by the bank 200 through an inkjet device or a nozzle coating device and then curing the liquid. The substrate 101 on which the light emitting diode E is formed, on which the organic light emitting layer 123 is formed through the driving thin film transistor DTr and the liquid organic light emitting material, is encapsulated by the encapsulation substrate 102.

That is, the semiconductor layer 103 is formed in the non-emission region NEA of the pixel region P on the substrate 101. The semiconductor layer 103 is made of silicon and the active region 103a forming a channel is formed at the center of the semiconductor layer 103. Further, both sides of the active region 103a are composed of source and drain regions 103b and 103c doped with high-concentration impurities.

A gate insulating film 105 is formed above the semiconductor layer 103 .

A gate electrode 107 and a gate wiring extending in one direction (not shown) are formed above the gate insulating layer 105 to correspond to the active region 103a of the semiconductor layer 103 .

In addition, an interlayer insulating film 109a is formed on the entire upper surface of the gate electrode 107 and the gate wiring (not shown). First and second semiconductor layer contact holes 116 exposing the source and drain regions 103b and 103c, respectively, are provided.

Next, the upper portion of the interlayer insulating film 109a including the first and second semiconductor layer contact holes 116 is spaced apart from each other and exposed through the first and second semiconductor layer contact holes 116, the source and drain regions 103b, Source and drain electrodes 110a and 110b contacting 103c, respectively, are formed.

And, a protective layer 109b having a drain contact hole 117 exposing the drain electrode 110b on top of the source and drain electrodes 110a and 110b and the interlayer insulating film 109a exposed between the two electrodes 110a and 110b. this is formed

At this time, the semiconductor layer 103 including the source and drain electrodes 110a and 110b and the source and drain regions 103b and 103c in contact with the electrodes 110a and 110b and a gate insulating film formed on the semiconductor layer 103 105 and the gate electrode 107 form a driving thin film transistor (DTr).

At this time, a data line 130 intersecting with a gate line (not shown) to define the pixel region P is formed. And, although not shown in the drawing, the switching thin film transistor (not shown) has the same structure as the driving thin film transistor DTr and is connected to the driving thin film transistor DTr.

In addition, the switching thin film transistor (not shown) and the driving thin film transistor (DTr) are shown as an example of a co-planar type in which the semiconductor layer 103 is made of a polysilicon semiconductor layer in the drawing, and as a modification thereof, pure And it may be formed as a bottom gate type made of amorphous silicon of impurities.

It is connected to the drain electrode 110b of the driving thin film transistor DTr and emits light, for example, with a material having a relatively high work function value, in the light emitting area EA, which is an area that substantially displays an image, on the top of the protective layer 109b. As one component constituting the diode E, a first electrode 121 constituting an anode is formed.

The first electrode 121 is formed for each pixel region P, and a bank 200 is located in the non-emission area NEA between the first electrodes 121 formed for each pixel region P. .

That is, the first electrode 121 is formed in a structure in which the first electrode 121 is separated for each pixel region P by using the bank 200 as a boundary for each pixel region P.

Here, the OLED 100 according to the first embodiment of the present invention is characterized in that the bank 200 is made of a metal material having a reflectance, and the bank 200 has an end of the first electrode 121 It has a structure that completely encloses, that is, a part of the upper surface and side surface of the first electrode 121 are all covered by the bank 200 .

In this case, an insulating layer 210 is interposed between the bank 200 and the first electrode 121 .

Therefore, the light extraction efficiency of the OLED 100 according to the first embodiment of the present invention is improved. We will look into this in more detail later.

An organic emission layer 123 is formed on the first electrode 121 .

At this time, the organic light emitting layer 123 is formed by spraying or coating a liquid organic light emitting material into the bank 200 through an inkjet device or a nozzle coating device and then curing the organic light emitting material.

The organic light emitting layer 123 may be composed of a single layer made of a light emitting material, and may include a hole injection layer, a hole transport layer, an emitting material layer, and an electron transport layer to increase light emitting efficiency. It may be composed of multiple layers of an electron transport layer and an electron injection layer.

The organic light emitting layer 123 expresses red (R), green (G), and blue (B) colors or white (W) colors for each pixel area P.

In addition, a second electrode 125 forming a cathode is formed on the entire surface of the organic light emitting layer 123 .

At this time, the second electrode 125 may be made of an opaque conductive material, for example, a metal material having a relatively low work function value, such as aluminum (Al), aluminum alloy (AlNd), silver (Ag), or magnesium (Mg). , Gold (Au), aluminum magnesium alloy (AlMg) is preferably formed of one material selected.

At this time, the first electrode 121, the organic light emitting layer 123, and the second electrode 125 form a light emitting diode (E).

When a predetermined voltage is applied to the first electrode 121 and the second electrode 125 according to the selected color signal, the OLED 100 receives holes injected from the first electrode 121 and from the second electrode 125. The provided electrons are transported to the organic light emitting layer 123 to form excitons, and when these excitons transition from an excited state to a ground state, light is generated and emitted in the form of visible light.

At this time, since the emitted light passes through the transparent first electrode 121 and goes out, the OLED 100 implements an arbitrary image.

In addition, an encapsulation substrate 102 for encapsulation is provided above the driving thin film transistor DTr and the light emitting diode E.

Here, the substrate 101 and the encap substrate 102 are provided with an adhesive (not shown) made of a sealant or frit along their edges, and the substrate 101 and the encap substrate 102 are formed by this adhesive (not shown). is bonded to maintain the panel state.

At this time, a vacuum state may be formed between the substrate 101 and the encap substrate 102 spaced apart from each other, or an inert gas atmosphere may be obtained by being filled with an inert gas.

The substrate 101 and the encapsulation substrate 102 may be made of glass, plastic, stainless steel, metal foil, or the like.

Here, when the substrate 101 and the encapsulation substrate 102 are formed with metal foil, they can be formed to have a thickness of 5 to 100 μm, and the substrate 101 and the encapsulation substrate 102 are formed by a glass or rolling method. It can be formed with a thinner thickness compared to the case of making it possible to reduce the overall thickness of the OLED (100).

In addition, although the thickness of the OLED 100 is reduced, the rigidity and durability of the OLED 100 itself can be improved.

On the other hand, the OLED 100 according to the above-described embodiment has been described and illustrated that the encapsulation substrate 102 for encapsulation is provided in a form facing and spaced apart from the substrate 101, but as a modified example, the encapsulation substrate 102 ) may be configured to contact the second electrode 125 provided on the uppermost layer of the substrate 101 in the form of a film including an adhesive layer (not shown).

In addition, as another modified example according to the embodiment of the present invention, an organic insulating film or an inorganic insulating film may be further provided on the second electrode 125 to form a capping film (not shown), and the organic insulating film or inorganic insulating film may be formed thereon. It may be used as an encapsulation film (not shown) by itself, and in this case, the encapsulation substrate 102 may be omitted.

As described above, in the OLED 100 according to the first embodiment of the present invention, the bank 200 is made of a metal having reflectance and the bank 200 is formed to surround the end of the first electrode 121, thereby , The light extraction efficiency of the OLED 100 is improved.

Through this, the luminance of the OLED 100 is improved, and since the driving voltage of the OLED 100 does not need to be increased in order to increase the luminance of the OLED 100, the organic light emitting layer 123 according to the driving voltage increases. Deterioration can be prevented from occurring, and through this, the lifetime of the OLED 100 can be prevented from being shortened.

2 is a diagram for explaining a mechanism for improving light extraction efficiency of an OLED according to a first embodiment of the present invention.

As shown, on the substrate (101 in FIG. 1) on which the first electrode 121 is formed, a driving thin film transistor (DTr in FIG. 1) and various wirings are formed to define a pixel area (P in FIG. 1). A bank 200 is formed to divide the light emitting area NEA from the light emitting area EA in which the light emitting diode E is formed.

Here, the OLED ( 100 in FIG. 1 ), which cures after spraying or dropping the liquid organic light emitting material on the area surrounded by the partition wall through an inkjet device or a nozzle coating device, applies the liquid organic light emitting material to each pixel area through an inkjet device. In order to spray each (P in Fig. 1) or drop through a nozzle coating device, the organic light emitting material in the liquid state is essentially first to prevent flow to the periphery within each pixel area (P in Fig. 1). A bank 200 in the form of enclosing each pixel region (P in FIG. 1) in which the electrode 121 is formed is required.

Therefore, the bank 200 is provided along the boundary of each pixel area (P in FIG. 1).

At this time, in the OLED (100 in FIG. 1 ) according to the first embodiment of the present invention, the bank 200 is made of a metal material having reflectivity, and the bank 200 completely surrounds the end of the first electrode 121. It is characterized by forming a catalog.

And, it is characterized in that the insulating layer 210 is interposed between the bank 200 and the first electrode 121 . The insulating layer 210 is to prevent the bank 200 made of a metal material and the first electrode 121 from being energized with each other.

Through this, while light emitted from the organic light emitting layer 123 passes through the first electrode 121 and goes out, some of the light is reflected by the bank 200 and goes out.

Accordingly, the light extraction efficiency of the OLED (100 in FIG. 1) is improved.

Looking at this in more detail, in a general OLED, in the process of light emitted from the organic light emitting layer passing through the first electrode and going out, the light is totally reflected at the interface between the first electrode and the protective layer positioned below the first electrode. , At this time, some of the total reflected light is absorbed and scattered by the bank and is lost.

In contrast, in the OLED (100 in FIG. 1 ) according to the first embodiment of the present invention, the bank 200 is formed of a metal material having reflectivity and the bank 200 is formed to surround the end of the first electrode 121. By doing this, the light totally reflected at the interface between the first electrode 121 and the protective layer 109b is reflected again by the bank 200 and is allowed to go out of the first electrode 121 .

Therefore, since the amount of light emitted to the outside of the first electrode 121 is increased, the light extraction efficiency of the OLED (100 in FIG. 1) is improved.

Here, the bank 200 contains at least one selected from silver (Ag), chromium (Cr), aluminum (Al), molybdenum (Mo), gold (Au), titanium (Ti), and magnesium (Mg) having high reflectivity. It is preferable to use

In addition, the insulating layer 210 interposed between the bank 200 and the first electrode 121 may be formed of inorganic insulating films such as silicon nitride (SiNx) and silicon oxide (SiOx). At this time, the insulating layer 210 is It is preferable to have a light refractive index similar to that of the first electrode 121 .

For example, when the first electrode 121 has a light refractive index of 1.8 to 2, the insulating layer 210 is also formed to have a light refractive index of 1.8 to 2.

This prevents light totally reflected at the interface between the first electrode 121 and the protective layer 109b from being totally reflected again between the first electrode 121 and the insulating layer 210, so that the first electrode 121 This is to ensure that all of the light totally reflected at the interface between the bank 200 and the passivation layer 109b is reflected by the bank 200 .

Then, the light reflected by the bank 200 is totally reflected between the first electrode 121 and the insulating layer 210, and passes through the first electrode 121 without being lost and goes out to the outside, thereby forming an OLED (Fig. This is to improve the light extraction efficiency of 100 of 1).

3a to 3b are simulation results obtained by comparing and measuring light efficiency and color characteristics of an OLED according to a first embodiment of the present invention and a general OLED.

Prior to the description, the simulation used a blue OLED emitting blue light, Sample 1 represents a general OLED, and Sample 2 represents an OLED according to the first embodiment of the present invention.

After applying the same voltage to both Sample 1 and Sample 2, light efficiency and color characteristics were measured.

Referring to the graph of FIG. 3A, it can be confirmed that the color characteristics of Sample 1 and Sample 2 are 0.137 (CIEy), indicating equivalent characteristics.

However, referring to FIG. 3B , it can be confirmed that the light efficiency of Sample 2 is 1.5 cd/A at the same luminance, which is 3.5 cd/A higher than the light efficiency of Sample 1, which is 7.0 cd/A.

That is, in the OLED (100 in FIG. 1) according to the first embodiment of the present invention, the bank (200 in FIG. 2) is made of a metal material having a reflectance, and the bank (200 in FIG. 2) is the first electrode (200 in FIG. It can be confirmed that the light extraction efficiency of the OLED (100 in FIG. 1) is improved by forming the end of 121 of Fig. 2) to completely cover the color characteristics of the light emitted from the OLED (100 in FIG. 1) without affecting the color characteristics. can

As described above, in the OLED (100 in FIG. 1 ) according to the first embodiment of the present invention, the bank (200 in FIG. 2 ) is made of a metal having a reflectance, and the bank (200 in FIG. 2 ) is a first electrode ( By being formed to surround the end of 121 in FIG. 2), the light extraction efficiency of the OLED (100 in FIG. 1) is improved.

Through this, the luminance of the OLED (100 in FIG. 1) is improved, and since it is not necessary to increase the driving voltage of the OLED (100 in FIG. 1) to increase the luminance of the OLED (100 in FIG. 1), the driving voltage is Deterioration of the organic light emitting layer (123 in FIG. 2) caused by the increase in height can be prevented, and through this, the lifespan of the OLED (100 in FIG. 1) can be prevented from being shortened.

4 is a diagram for explaining a mechanism for improving light extraction efficiency of an OLED according to a second embodiment of the present invention.

As shown, on the substrate (101 in FIG. 1) on which the first electrode 121 is formed, a driving thin film transistor (DTr in FIG. 1) and various wirings are formed to define a pixel area (P in FIG. 1). A bank 200 is formed to divide the light emitting area NEA from the light emitting area EA in which the light emitting diode E is formed.

At this time, in the OLED (100 in FIG. 1 ) according to the second embodiment of the present invention, the bank 200 is made of a metal material having reflectivity, and the bank 200 completely surrounds the end of the first electrode 121. It is characterized by forming a catalog.

Through this, while light emitted from the organic light emitting layer 123 passes through the first electrode 121 and goes out, some of the light is reflected by the bank 200 and goes out. Accordingly, the light extraction efficiency of the OLED (100 in FIG. 1) is improved.

And, it is characterized in that the insulating layer 210 is interposed between the bank 200 and the first electrode 121 and between the bank 200 and the protective layer 109b. The insulating layer 210 is to prevent the bank 200 made of a metal material and the first electrode 121 from being energized with each other.

Here, the insulating layer 210 is formed to be interposed between the bank 200 and the first electrode 121 and between the bank 200 and the protective layer 109b, so that the insulating layer 210 is planarly formed between the bank 200 and the first electrode 121. It is formed to have the same area and shape, and through this, the bank 200 and the insulating layer 210 can be simultaneously formed through the same mask process, so that a separate process for forming the insulating layer 210 can be omitted.

The insulating layer 210 may be formed of inorganic insulating films such as silicon nitride (SiNx) and silicon oxide (SiOx). In this case, the insulating layer 210 is preferably formed to have a light refractive index similar to that of the first electrode 121. do.

For example, when the first electrode 121 has a light refractive index of 1.8 to 2, the insulating layer 210 is also formed to have a light refractive index of 1.8 to 2.

This prevents light totally reflected at the interface between the first electrode 121 and the protective layer 109b from being totally reflected again between the first electrode 121 and the insulating layer 210, so that the first electrode 121 This is to ensure that all of the light totally reflected at the interface between the bank 200 and the passivation layer 109b is reflected by the bank 200 .

Then, the light reflected by the bank 200 is totally reflected between the first electrode 121 and the insulating layer 210, and passes through the first electrode 121 without being lost and goes out to the outside, thereby forming an OLED (Fig. This is to improve the light extraction efficiency of 100 of 1).

5 is a diagram for explaining a mechanism for improving light extraction efficiency of an OLED according to a third embodiment of the present invention.

As shown, on the substrate (101 in FIG. 1) on which the first electrode 121 is formed, a driving thin film transistor (DTr in FIG. 1) and various wirings are formed to define a pixel area (P in FIG. 1). A first bank 220 is formed to divide the light emitting area NEA from the light emitting area EA in which the light emitting diodes E are formed.

Here, the OLED ( 100 in FIG. 1 ), which cures after spraying or dropping the liquid organic light emitting material on the area surrounded by the partition wall through an inkjet device or a nozzle coating device, applies the liquid organic light emitting material to each pixel area through an inkjet device. In order to spray each (P in FIG. 1) or drop through a nozzle coating device, the organic light emitting material in a liquid state is essentially first to prevent flow to the periphery within each pixel area (P in FIG. 1). The first bank 220 in the form of enclosing each pixel region (P in FIG. 1) in which the electrode 121 is formed is required.

Therefore, the first bank 220 is provided along the boundary of each pixel region (P in FIG. 1).

At this time, the first bank 220 is made of a material having a hydrophobic property, and the first bank 220 may be made of various materials such as an organic material having hydrophobicity or an inorganic material having hydrophobicity. The reason why the first bank 220 has a hydrophobic characteristic is that when the liquid organic light emitting material is sprayed or dropped, the pixel area surrounded by the first bank 220 (P in FIG. 1) is caused by an error of the equipment itself. This is so that even if a predetermined amount is sprayed on the first bank 220 as it is not sprayed at the center of the inside but is sprayed slightly biased, it flows down from the first bank 220 and is located within each pixel area (P in FIG. 1).

In addition, this is to suppress the overflow of the liquid organic light emitting material to the upper part of the first bank 220 even when the injection amount is slightly excessive.

When the first bank 220 has a hydrophobic property, it has a property of repelling the liquid organic light emitting material having a hydrophilic property, so the organic light emitting material is not coated on the top of the first bank 220 and the first bank 220 ), it is possible to gather intensively only in the area surrounded by

Here, the OLED (100 in FIG. 1 ) according to the third embodiment of the present invention has reflectance between the first bank 220 and the first electrode 121 and between the first bank 220 and the protective layer 109b. The second bank 200 is located, and an insulating layer 210 is interposed between the second bank 200 and the first electrode 121 and between the second bank 200 and the protective layer 109b. .

At this time, the second bank 200 has a structure surrounding the end of the first electrode 121 .

Through this, while the light emitted from the organic light emitting layer 123 passes through the first electrode 121 and goes out, some of the light is reflected by the second bank 200 and goes out.

That is, the OLED (100 in FIG. 1 ) according to the third embodiment of the present invention has reflectance between the first bank 220 and the first electrode 121 and between the first bank 220 and the protective layer 109b. By further forming the second bank 200 made of a metal material, the light totally reflected at the interface between the first electrode 121 and the protective layer 109b is reflected again by the second bank 200, It is to go out of the electrode 121.

Therefore, since the amount of light emitted to the outside of the first electrode 121 is increased, the light extraction efficiency of the OLED (100 in FIG. 1) is improved.

Here, the second bank 200 includes at least one selected from silver (Ag), chromium (Cr), aluminum (Al), molybdenum (Mo), gold (Au), titanium (Ti), and magnesium (Mg) having high reflectivity. It is preferable to use one.

In addition, the insulating layer 210 interposed between the second bank 200 and the first electrode 121 and between the second bank 200 and the protective layer 109b is made of silicon nitride (SiNx) or silicon oxide (SiOx). In this case, the insulating layer 210 is preferably formed to have a light refractive index similar to that of the first electrode 121 .

For example, when the first electrode 121 has a light refractive index of 1.8 to 2, the insulating layer 210 is also formed to have a light refractive index of 1.8 to 2.

This prevents light totally reflected at the interface between the first electrode 121 and the protective layer 109b from being totally reflected again between the first electrode 121 and the insulating layer 210, so that the first electrode 121 This is to ensure that all of the light totally reflected at the interface between the first bank and the protective layer 109b is reflected by the second bank 200 .

Then, the light reflected by the second bank 200 is totally reflected between the first electrode 121 and the insulating layer 210, and passes through the first electrode 121 without being lost and goes out to the outside, OLED. This is to improve the light extraction efficiency of (100 in FIG. 1).

Here, the insulating layer 210 and the second bank 200 are formed to have the same area and shape as the first bank 220 in plan view, through which the first bank 220 and the second bank 200 and the insulation Since the layer 210 can be simultaneously formed through the same mask process, a separate process for forming the second bank 200 and the insulating layer 210 can be omitted.

As described above, the OLED (100 in FIG. 1 ) according to the third embodiment of the present invention is between the first bank 220 and the first electrode 121 and between the first bank 220 and the protective layer 109b. By further forming the second bank 220 made of a metal material having reflectance, the light extraction efficiency of the OLED (100 in FIG. 1) is improved.

Through this, the luminance of the OLED (100 in FIG. 1) is improved, and since it is not necessary to increase the driving voltage of the OLED (100 in FIG. 1) to increase the luminance of the OLED (100 in FIG. 1), the driving voltage is It is possible to prevent deterioration of the organic light emitting layer 123 caused by the increase in height, and through this, it is possible to prevent the life span of the OLED (100 in FIG. 1 ) from being shortened.

The present invention is not limited to the above embodiments, and can be practiced with various changes without departing from the spirit of the present invention.

109b: protective layer
121: first electrode, 123: organic light emitting layer, 125: second electrode
200: bank
210: insulating layer

Claims (11)

a first substrate on which a plurality of pixel areas each including a light-emitting area and a non-light-emitting area are defined;
a first electrode provided for each pixel area;
a first bank formed in the non-emission area, surrounding each pixel area, overlapping an edge of the first electrode, and made of a metal material having reflectivity;
an insulating layer interposed between the first bank and the first electrode in the non-emission area;
an organic light emitting layer positioned above the first electrode in the region surrounded by the first bank of the light emitting region;
And a second electrode positioned on the organic light emitting layer,
The first electrode is disposed in the light emitting region and extends into the non-light emitting region, and the insulating layer and the first bank are disposed to surround the top and side surfaces of the first electrode in the non-light emitting region to emit light from the organic light emitting layer. An organic light emitting device in which the emitted light is reflected from the first bank surrounding the first electrode in the non-emission region.
According to claim 1,
The insulating layer has the same light refractive index as the first electrode organic light emitting device.
According to claim 1,
The insulating layer has the same area and shape as the first bank.
According to claim 1,
The insulating layer is an organic light emitting device made of one of silicon nitride (SiNx) and silicon oxide (SiOx).
According to claim 1,
Wherein the first bank is made of at least one selected from among silver (Ag), chromium (Cr), aluminum (Al), molybdenum (Mo), gold (Au), titanium (Ti), and magnesium (Mg).
According to claim 1,
An organic light emitting device in which a second bank having a hydrophobic property is located above the first bank.
According to claim 6,
The first bank, the insulating layer, and the second bank have the same area and shape in plan view.
According to claim 1,
a driving thin film transistor formed below the first electrode in each of the pixel areas on the first substrate;
A protective layer formed covering the driving thin film transistor and exposing the drain electrode of the driving thin film transistor.
and wherein the first electrode contacts the drain electrode of the driving thin film transistor in each of the pixel areas over the passivation layer.
According to claim 1,
An organic light emitting device having a second substrate facing the first substrate corresponding to the first substrate or an encapsulation film that contacts the second electrode and serves as the second substrate. The organic light emitting device of claim 1 , wherein the first electrode extends along the periphery of the pixel region into the non-emission region.
The organic light emitting device of claim 1 , wherein side surfaces of the first bank and the insulating layer in contact with the organic light emitting layer are linear.

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