KR20140087435A - Organic Light Emitting Diode Display Device and Method for Manufacturing The Same - Google Patents

Abstract

An organic light emitting display device according to an aspect of the present invention includes a substrate on which a display region and a non-display region surrounding the display region are defined; an organic light emitting device which is formed on the substrate and includes an anode electrode, an organic light emitting layer, and a cathode electrode; a thin film encapsulation layer which is formed on the organic light emitting device and includes at least one inorganic layer and at least one organic layer formed alternatively; and a protection layer which is formed on the thin film encapsulation layer and protects the thin film encapsulation layer. The organic layer has a constant thickness on the non-display region.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display and a method of manufacturing the same, and more particularly, to an active organic light emitting display and a method of manufacturing the same.

With the development of information and communication technology, state-of-the-art flat panel display devices are in the spotlight. Flat panel displays are becoming more thin and more portable. In particular, organic electroluminescent display devices, which are attracting attention as a next-generation liquid crystal display device, are self-luminous devices, and thus there is an advantage that a lightweight thin flat panel device can be realized compared to a liquid crystal display device. Further, the organic light emitting display device is an eco-friendly flat panel display device having a wide viewing angle, excellent contrast ratio, quick response time and low power consumption.

Since the organic light emitting display device adopts an organic light emitting layer composed of an organic material for the light emitting layer replacing the backlight, it is possible to prevent deterioration due to deterioration of organic materials and moisture permeation to improve lifetime and improve reliability of light emission. Is emerging as a key issue in technology development of display devices.

Encapsulation techniques for sealing the organic light emitting layer from the outside to prevent damage to the organic light emitting layer include a front seal type in which a thin film is formed on the organic light emitting layer and an edge sealing seal type. Here, the front sealing (hereinafter referred to as the face seal) is a method of forming the thin film sealing layer on the organic light emitting layer. In the front sealing method, the uniformity of the film depends on the sealing effect, and cracks are particularly likely to occur in the edge region.

1 is a cross-sectional view illustrating a portion of a general organic light emitting display device.

1, a typical organic light emitting display device includes a substrate 101, an organic light emitting diode 110, and a thin film encapsulation layer 120. The thin film encapsulation layer 120 is formed in a front hermetically sealed manner.

An organic light emitting device 110 is formed on a substrate 101 and a thin film sealing layer 120 is formed on the organic light emitting device 110 to protect the organic light emitting device 110. Generally, the thin film encapsulation layer 120 is a multi-layer in which an inorganic layer 121 and an organic layer 122 are alternately formed. The inorganic layer 121 is used as a barrier layer and the organic layer 122 is used as a decoupling layer. In the case of the organic layer 122, it is deposited in a monomer state and polymerized through curing.

One of the main purposes of the organic layer 122 is to cover the foreign substance on the substrate 101 or the inorganic layer 121 so that the thickness of the inorganic layer 121 formed on the organic layer 122 is uniformly formed. Generally, the width of the organic layer 122 is narrow and the width of the inorganic layer 121 is wide so that the inorganic layer 121 surrounds the organic layer 122. This is because when the organic layer 122 is exposed to the outside This is because the organic layer 122 becomes a path for moisture permeation.

In order for the inorganic layer 121 to uniformly cover the organic layer 122 which is formed several times to several tens of times thicker than the inorganic layer 121, the thickness of the edge area of about 100 to 500 μm of the organic layer 122 must be gradually reduced. If foreign matter exists in this area, the organic matter may be exposed to the outside and become a path of moisture permeation, and the moisture permeation may proceed unpredictably, resulting in unexpected lighting failure.

Since only the inorganic layer 121 is present outside the organic layer 122 and the stress applied to each of the inorganic layer 121 and the organic layer 122 locally differs, the thin film is cracked or cracked This also leads to unexpected lighting failure, driving reliability may be deteriorated, and the lifetime prediction of the organic light emitting display device becomes impossible.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic light emitting display device capable of improving driving reliability.

According to an aspect of the present invention, there is provided an organic light emitting display including: a substrate having a display region and a non-display region surrounding the display region; An organic light emitting element formed on the substrate and including an anode electrode, an organic light emitting layer, and a cathode electrode; A thin film encapsulation layer formed on the organic light emitting element and including at least one inorganic layer and at least one organic layer alternately formed; And a protective layer formed on the thin-film encapsulation layer and protecting the thin-film encapsulation layer, wherein the thickness of the organic layer is constant in the non-display area.

According to another aspect of the present invention, there is provided a method of manufacturing an organic light emitting display, including: forming an organic light emitting diode on a substrate on which a display region and a non-display region surrounding the display region are defined; Forming a thin film encapsulation layer by sequentially laminating an inorganic layer and an organic layer on an area of the organic light emitting element that is larger than an area of the non-display area; And removing an edge region of the thin film encapsulation layer so that an end face of the inorganic layer and the organic layer is exposed at an interface between the non-display area and the outside, The thickness of the first layer begins to decrease.

According to the present invention, it is possible to maintain the thickness of the organic layer uniformly in the thin-film encapsulating layer, to prevent the occurrence of cracks due to the difference in stress between the foreign substance and the inorganic layer, and to prevent the unfavorable light- have.

Further, according to the present invention, the organic layer of the thin film encapsulation layer formed to have a uniform thickness is exposed, and the rate of progress of moisture permeation in the edge region of the organic layer can be predicted in advance.

Further, according to the present invention, by predicting the rate of progress of the moisture permeation of the edge region of the organic layer and setting the non-display region to be wider than the moisture permeation progression range, it is possible to reduce unforeseen lighting failure, It is effective.

1 is a cross-sectional view of a general organic light emitting display device of the present invention;
2 is a cross-sectional view illustrating an organic light emitting display device according to an embodiment of the present invention;
3 is a cross-sectional view illustrating an organic light emitting display device according to another embodiment of the present invention;
FIG. 4 is a cross-sectional view illustrating an organic light emitting display device according to another embodiment of the present invention; FIG.
FIG. 5 is a plan view showing a state in which a thin film encapsulation layer is formed during a manufacturing process of an organic light emitting display according to an embodiment of the present invention; FIG. And
6 is a plan view illustrating a method of cutting an edge region of a thin-film encapsulation layer during a manufacturing process of an organic light emitting display according to an embodiment of the present invention.

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

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

2, the organic light emitting display includes a substrate 201, an organic light emitting diode 210, and a thin film encapsulation layer 220.

First, the substrate 201 may be a glass or a metal including any one of aluminum (Al) and copper (Cu). In addition, the substrate 201 may be formed of a flexible material that can be bent, and a material having excellent heat resistance and durability to withstand high temperatures and various chemicals. For example, the substrate 201 may be formed of a material selected from the group consisting of polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylenenaphthalate (PET), polyethylene terephthalate , polyehtyleneterephthalate), and the like.

Next, an organic light emitting element 210 is formed on the substrate 201. [ The organic light emitting device 210 may include an anode electrode (not shown), an organic light emitting layer (not shown), and a cathode electrode (not shown).

In the case of the top emission type, light emitted from the organic light emitting layer can be emitted through the cathode electrode formed on the top surface. In the case of the bottom emission type, light emitted from the organic light emitting layer can be emitted through the anode electrode formed on the backside.

The anode electrode may be connected to a thin film transistor (not shown) formed below. The thin film transistor may be a driving thin film transistor. The driving transistor receives a scan signal from a switching transistor. After receiving the scan signal from the thin film transistor, the anode electrode can supply holes to the organic light emitting layer.

The anode electrode may be formed of a material having a large work function so as to supply holes to the organic light emitting layer. For example, the anode electrode may be formed of a transparent conductive oxide, and may be formed of indium tin oxide (ITO), indium zinc oxide, and indium tin zinc Oxide) may be formed.

Next, in the organic luminescent layer, the holes supplied from the anode electrode and the electrons supplied from the cathode electrode meet to form an exciton, and then the exciton transitions to the ground state, and the inherent characteristics of the material constituting the organic luminescent layer Light having a wavelength as much as the band gap energy can be emitted.

The organic light emitting layer includes a hole injection layer, a hole transportation layer, an electron injection layer, and an electron transportation layer so as to receive holes and electrons as described above. .

Since the organic luminescent layer is made of organic materials that are susceptible to moisture and other foreign substances that can permeate from the outside, a protective layer is necessary to protect the organic luminescent layer. The thin film encapsulation layer 220 may be formed on the organic light emitting device 210 as the protective layer.

Next, the cathode electrode may preferably be formed of a material having a low work function so as to supply electrons to the organic light emitting layer. For example, the cathode electrode may be formed of a metal or an alloy including any one of silver (Ag), copper (Cu), and aluminum (Al). In the case of the top surface emission type, since the light emitted from the organic light emitting layer is emitted in the direction of the cathode electrode, the cathode electrode may be a semi-transparent thin film in which the metal or alloy is formed as a very thin film.

Next, a thin film encapsulating layer 220 is formed on the organic light emitting element 210. [ The thin film encapsulation layer 220 may include at least one inorganic layer 221 and at least one organic layer 222. The thin film encapsulation layer 220 may include at least one inorganic layer 221 and at least one organic layer 222 alternately stacked and an inorganic layer 221 on which an inorganic layer 221 is stacked at the top and bottom, ) / Organic layer 222 / inorganic layer 221 structure.

The inorganic layer 221 may serve as a barrier layer for protecting the organic layer 222 and may be formed to be thinner than the organic layer 222. The inorganic layer 221 may be formed of a material such as silicon oxide (SiOx), silicon oxynitride (SiOxNy), silicon nitride (SiNx), silicon carbide oxide (SiOxCy), aluminum oxide (AlOx), indium tin oxide (ITO), zinc oxide , And aluminum aluminum oxide (Al-ZnOx).

The inorganic layer 221 may be formed by a sputtering method or an atomic layer deposition method. The first inorganic layer 221 formed on the organic light emitting diode 210 may serve as a protective layer for protecting the organic light emitting diode 210 and may serve as a protective layer for protecting the thin film sealing layer 220 from the outside. have. The first organic layer 222 formed on the first inorganic layer 221 may serve to flatten the unevenness of the underlying structure including the organic light emitting device 210. At the same time, foreign matter that may be present on the first inorganic layer 221 may be planarized so that the thickness of the inorganic layer 221 and the organic layer 222 formed on the first organic layer 222 may be uniformly formed.

The organic layer 222 may serve as a buffer layer of the inorganic layer 221 and may be formed as a thin film several times to several tens of times thicker than the inorganic layer 221. The organic layer 222 may be formed of any one of acrylate, epoxy series polymer, imide series polymer, and benzocyclobutene series resin.

The organic layer 222 may be formed of a material having a planarizing property. The irregularities of the lower structure can be flattened or the foreign substances that may be present on the formed film can be covered and planarized. After forming the inorganic layer 221, the remnants of the particles and the inorganic layer 221 formed on the inorganic layer 221 may remain. The organic layer 222 is formed on the inorganic layer 221 to prevent buffering action and cracking of the inorganic layer 221 and to prevent the organic layer 222 and the organic light- It is possible to prevent damage to the first electrode 210.

The organic layer 222 may be formed by a thermal deposition method. Further, after the formation of the organic layer 222, various processes including a heat treatment process may be added to release the gas present therein.

The inorganic layer 221 and the organic layer 222 may be formed in a uniform thickness on the entire surface of the substrate 201 including the non-display area N / A as well as the display area A / A. Since the inorganic layer 221 and the organic layer 222 are formed by an evaporation method using an open mask, the thickness of the edge region formed in the non-display region N / A can be reduced. Particularly, when foreign matter having a height larger than the thickness of the organic layer 222 is present in the non-display area N / A where the organic layer 222 has a reduced thickness, cracks can be generated and the moisture permeation can be accelerated.

However, in the present invention, as shown in FIG. 2, the organic layer 222 and all the inorganic layers 221 except the first organic layer 222 are formed to have a uniform thickness up to the end of the non-display area N / A have. Therefore, it is possible to prevent or delay the moisture permeation by preventing the occurrence of cracks due to foreign matter.

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

As shown in FIG. 3, the organic light emitting display device according to another embodiment of the present invention further includes a protective layer 230.

The protective layer 230 is formed on the thin-film encapsulating layer 220. The protective layer 230 may be formed of the same material as the inorganic layer 221 and may be formed of a material such as silicon oxide (SiOx), silicon oxynitride (SiOxNy), silicon nitride (SiNx), silicon carbide oxide (SiOxCy) And may be formed of any one of aluminum oxide (AlOx), indium tin oxide (ITO), zinc oxide (ZnOx), and aluminum oxide (Al-ZnOx).

The protective layer 230 may be formed on the thin film encapsulation layer 220 and simultaneously surround the exposed end face of the inorganic layer 221 and the organic layer 222. The protective layer 230 may be formed of a material having excellent step coverage characteristics so as to surround the exposed cross section of the inorganic layer 221 and the organic layer 222. [ Therefore, the protective layer 230 may be formed of a transparent conductive oxide having excellent step coverage characteristics. For example, any one of indium tin oxide (ITO), indium zinc oxide (ITO), and indium tin zinc oxide (ITO).

The protective layer 230 may be formed of a material having excellent step coverage characteristics as described above to densely seal the exposed end faces of the inorganic layer 221 and the organic layer 222. Even if the protective layer 230 is formed of the same material as the inorganic layer 221 and the exposed end faces of the inorganic layer 221 and the organic layer 222 are not tightly closed, the permeation rate of the organic layer 222 is decreased It is possible to delay the occurrence of defective light emission.

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

4, the organic light emitting display device according to another embodiment of the present invention further includes a curing unit 240 formed in a non-display area N / A of the organic layer 222. Referring to FIG.

The hardened portion 240 may be formed by irradiating the organic layer 222 with a laser. The organic layer 222 may be formed by a thermal evaporation method. The organic layer 222 may be heat-treated to remove foreign substances such as gas contained therein, and may be heat-treated for curing the organic layer 222. In particular, since the organic layer 222 of the non-display area N / A is the position where the moisture permeation from the outside is started, the organic layer 222 of the non-display area N / A is hardened by the laser, So that the progress of the breathing can be further delayed.

The hardened portion 240 may be formed by repeatedly irradiating a laser after the organic layer 222 is formed, or may be formed by irradiating a laser at one time after the thin film encapsulation layer 220 is completely completed. A metal wiring region such as a pad portion (not shown) may exist on the substrate 201 of the non-display region N / A under the thin film encapsulation layer 220, though not shown in the drawing. Therefore, it is necessary to adjust the laser intensity so as not to damage the region. When the laser is irradiated to the thin sealing layer 220 in the direction of the thin sealing layer 220 at a time after the thin sealing layer 220 is formed , The pad portion, and the like can be prevented from being damaged.

5 is a plan view illustrating a state in which a thin film encapsulation layer is formed during a manufacturing process of an organic light emitting display according to an embodiment of the present invention.

5, the thin film encapsulation layer 220 is formed over the thin film encapsulation layer region T / A having a larger area than the non-display area N / A.

First, a substrate 201 having a larger area than the non-display area N / A is prepared, and then the organic light emitting element 210 is formed for each pixel.

Next, the inorganic layer 221 and the organic layer 222 can be alternately formed on the organic light emitting device 210 in the thin film encapsulation layer region T / A. At this time, the thicknesses of the inorganic layer 221 and the organic layer 222 must be uniformly formed not only in the display area A / A but also in the non-display area N / A. That is, the thickness of the inorganic layer 221 and the organic layer 222 should be uniform in the region where the thin film encapsulation layer 220 is subsequently cut.

When the first inorganic layer 221 is formed on the organic light emitting diode 210, the magnet is once positioned on the opposite side of the substrate 201, and then the open mask is aligned by a magnet. The open area of the mask can coincide with the thin-film encapsulation layer area (T / A). Then, a sputtering process is performed to deposit an inorganic material on the open region of the mask to form the inorganic layer 221 in the thin film sealing layer region (T / A).

In the case of forming the organic layer 222 on the inorganic layer 221, an organic material is deposited on the open region of the mask using a thermal evaporation method with an open mask aligned by a magnet, thereby forming a thin film encapsulation layer region T / A The organic layer 222 can be formed.

The thin film encapsulation layer 220 can be formed in the thin encapsulation layer region T / A by repeating the process of forming the inorganic layer 221 and the organic layer 222. [ The thin film encapsulation layer 220 is formed so as to gradually decrease in thickness from the region where the non-display region N / A ends, that is, the boundary between the non-display region N / A and the outside, .

6 is a cross-sectional view illustrating a method of cutting an edge region of a thin-film encapsulating layer during a manufacturing process of an organic light emitting display according to an embodiment of the present invention.

The thickness of the edge region of the thin film encapsulation layer 220 at the interface B between the non-display area N / A and the outside can be gradually reduced, as shown in Fig. The thin film encapsulation layer 220 is formed by a wheel scribing method as shown in FIG. 6 along a non-display area N / A having a uniform thickness and an interface B with the outside 220 can be cut and removed. At this time, not only the edge region of the thin film encapsulation layer 220 but also the substrate 201 can be cut at the same time.

The wheel scriber moves from the thin film sealing layer 220 toward the substrate 201 to cut the edge region of the thin film sealing layer 220 and the outer frame portion of the substrate 201, It may be cut.

In a region where the substrate 201 should not be cut, patterning may be performed using a conventional photolithography method. Only the edge regions located outside the non-display region N / A of the thin film encapsulation layer 220 are removed by patterning to remove metal wiring and the like formed on the substrate 201 and the non-display region N / A on the substrate 201 Can be protected without removing it.

In addition, the edge region of the thin film encapsulation layer 220 can be removed by using a tape. A tape is attached onto the substrate 201 corresponding to the edge region of the thin film sealing layer 220 to be removed before forming the thin film sealing layer 220 and the thin film sealing layer 220 is formed, The edge region of the thin film sealing layer 220 is removed and the end face of the inorganic layer 221 and the organic layer 222 can be exposed.

The inorganic layer 221 and the organic layer 222 of the thin film encapsulation layer 220 are formed to have a uniform thickness in the non-display area N / A and the organic layer 222 is exposed, 222 can be predicted so that the non-display area N / A of the substrate 201 is longer than the expected wettability progress distance, thereby increasing the yield of the organic light emitting display device. In addition, it is possible to reduce the production cost compared with the case of forming a sealing member having high precision and excellent sealing property, and to prevent defects such as lighting difficult to predict due to unpredictable causes such as cracks and the like, Can be improved.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

201: substrate 210: organic light emitting element
220: Thin film sealing layer 221: Inorganic layer
222: organic layer

Claims (12)

A substrate on which a display region and a non-display region surrounding the display region are defined;
An organic light emitting element formed on the substrate and including an anode electrode, an organic light emitting layer, and a cathode electrode;
A thin film encapsulation layer formed on the organic light emitting element and including at least one inorganic layer and at least one organic layer alternately formed; And
And a protective layer formed on the thin film sealing layer and protecting the thin film sealing layer,
Wherein the organic layer has a constant thickness in the non-display region.
The method according to claim 1,
Wherein a cross section of the inorganic layer and the organic layer is exposed in the non-display region.
3. The method of claim 2,
Wherein the protective layer surrounds the exposed end face of the inorganic layer and the organic layer.
The method according to claim 1,
Wherein the organic layer includes a hardened portion in the non-display region.
Forming an organic light emitting element on a substrate on which a display region and a non-display region surrounding the display region are defined;
Forming a thin film encapsulation layer by sequentially laminating an inorganic layer and an organic layer on a region larger than the non-display region on the organic light emitting element; And
And removing an edge region of the thin-film encapsulation layer such that an end face of the inorganic layer and the organic layer is exposed at an interface between the non-display area and the outside.
6. The method of claim 5,
The step of forming the thin film encapsulation layer includes:
Placing a magnet under the substrate and aligning the mask with the magnet on the substrate;
Depositing an inorganic material by a sputtering method using the mask to form an inorganic layer; And
Depositing an organic material on the inorganic layer by thermal evaporation and curing the organic layer by heat treatment;
Wherein the thickness of the organic layer is uniform in the non-display region, and the thickness of the organic layer starts to decrease from the boundary between the non-display region and the outside to the outside.
The method according to claim 6,
In the step of removing the edge region of the thin film sealing layer,
Wherein the magnetic field region of the thin film encapsulation layer is removed by a wheel scribing method.
The method according to claim 6,
In the step of removing the edge region of the thin film sealing layer,
Wherein the magnetic field region of the thin film encapsulation layer is patterned and removed.
The method according to claim 6,
In the step of removing the edge region of the thin film sealing layer,
Wherein the magnetic field region of the thin film sealing layer is removed by a tape.
10. The method of claim 9,
When the thin film encapsulation layer is removed by the tape,
Characterized in that an edge region of the thin film encapsulation layer is removed while the tape is placed on the substrate before the thin film encapsulation layer is formed and the tape is peeled off after the thin film encapsulation layer is formed, Device.
6. The method of claim 5,
The method of fabricating an organic light emitting display device includes:
And forming a hardened portion by irradiating the organic layer of the non-display region with a laser.
6. The method of claim 5,
The method of fabricating an organic light emitting display device includes:
And forming a protective layer surrounding the inorganic layer and the exposed end surface of the organic layer on the thin-film encapsulation layer.

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