KR101465620B1 - Method for encapsulation of OLED - Google Patents

Abstract

The present invention relates to a method of encapsulating an organic light emitting diode, comprising: forming a first encapsulation layer on a surface of an organic light emitting diode at a predetermined deposition rate; (b) forming a second encapsulation layer on the surface of the first encapsulation layer at a deposition rate that is slower or faster than the predetermined deposition rate, thereby forming a double encapsulation layer on the surface of the first encapsulation layer, , The generation of a gap in the sealing film is completely suppressed, so that the organic thin film layer and the cathode layer of the organic light emitting device are completely protected from oxygen or moisture.

Description

[0001] The present invention relates to a method for encapsulating an OLED,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of encapsulating an organic light emitting diode, and more particularly, to a method of encapsulating an organic light emitting diode to prevent an organic light emitting diode from being deteriorated by oxygen or moisture.

2. Description of the Related Art In recent years, a flat panel display (FPD) has been attracting attention as a display device due to rapid development of information and communication technology and expansion of the market.

Examples of such flat panel display devices include a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting diode (OLED).

Among them, organic light emitting diode (OLED) has very good advantages such as fast response speed, lower power consumption than conventional liquid crystal display devices, light weight, no need for separate backlight device, And has been attracting attention as a next-generation display device.

The organic light emitting device is a principle in which a proper energy difference is formed in the organic thin film by self-coating by applying a positive electrode film, an organic thin film and a negative electrode film on a substrate in order and applying a voltage between the anode and the cathode. That is, the injected electrons recombine with the holes, and the excitation energy that remains is generated by the light. In this case, since the wavelength of light generated according to the amount of dopant of the organic material can be controlled, full color can be realized.

The organic light emitting device is usually formed by sequentially stacking an anode layer, an organic thin film layer, and a cathode layer on a substrate.

As the anode, indium tin oxide (ITO) having a small surface resistance and good transparency is mainly used. In order to increase the luminous efficiency, the organic thin film has a hole injection layer, a hole transfer layer, ), An electron transfer layer, and an electron injection layer, and a LiF-Al metal film is used as a cathode.

Here, organic materials used as the light emitting layer are Alq3, TPD, PBD, m-MTADATA, TCTA, and the like.

In the organic light emitting device thus formed, the cathode layer is formed of a material having a low work function, for example, an alloy system having high reactivity based on alkali metals and alkaline earth metals. Since such reactive metals are easily oxidized by reacting with oxygen or moisture, And the lifetime of the device is shortened. Further, the organic thin film layer is also liable to be deteriorated under the influence of oxygen and moisture.

Therefore, a sealing structure is required to seal the organic light emitting element to protect it from oxygen and moisture.

Conventionally, the sealing structure of the organic light emitting diode can be implemented by various methods.

For example, a sealing structure in which a cap made of glass or metal is bonded to an anode over an organic light emitting element via a sealant is exemplified. Here, a getter, which is a moisture absorbent, is attached to the bottom surface of the cap through an adhesive tape, and this getter captures moisture flowing from the outside through the adhering portion to keep the device in a safe state.

However, the sealing structure of such a conventional organic light emitting device having a metal or glass cap has an advantage that it has an excellent shielding effect against oxygen and moisture, but since the whole thickness of the device becomes thick, It is difficult to realize the device.

In order to solve such a problem, a method of encapsulating an organic light emitting element using a polar thin film called a "sealing film" instead of a glass or metal cap has been proposed.

FIG. 1 is a schematic view showing a state in which a sealing film is deposited on an organic light emitting device. As shown in FIG. 1, the sealing film is formed to cover all the organic light emitting elements 10 having a structure in which a cathode layer, (Not shown).

The encapsulation film 20 is composed of a buffer layer, a planarization layer, and a passivation layer sequentially formed from the device side.

Here, the buffer layer and the passivation layer may be formed using a deposition technique such as a CVD (Chemical Vapor Deposition) method, or a metal oxide or nitride having an excellent barrier property against air and moisture.

In addition, the planarization layer serves to planarize the curvature of the organic thin film layer and the cathode layer, and is deposited using a polymer-based material.

However, although the sealing structure of the organic light emitting device having the sealing film as described above is suitable for use in an ultra-thin portable electronic device because the thickness of the entire organic light emitting device is thin, the sealing film is deposited by the CVD method, The organic thin film layer 20 and the cathode layer of the organic light emitting device are not completely protected from oxygen or moisture due to crystallization of the organic thin film layer 20 itself in the form of amorphous or polymer, there was.

DISCLOSURE OF THE INVENTION The present invention has been conceived in view of the above problems, and it is an object of the present invention to provide a method for depositing a double sealing film by vapor deposition or ALD deposition on an organic light emitting device, And the organic thin film layer and the cathode layer of the organic light emitting device are completely protected from oxygen or moisture.

According to another aspect of the present invention, there is provided a method of encapsulating an organic light emitting diode, comprising: (a) forming a first encapsulation layer on a surface of the organic light emitting device at a predetermined deposition rate; (b) forming a second encapsulation layer on the surface of the first encapsulation layer at a deposition rate that is slower or faster than the predetermined deposition rate.

In this case, the first encapsulation film may be formed by any one of a sputtering method, a thermal evaporation method, and a CVD method, and the second encapsulation film may be formed by any one of a sputtering method, a thermal evaporation method, a CVD method, Can be formed by a vapor deposition method

Here, the first encapsulation film and the second encapsulation film may be deposited as a homogeneous material.

Meanwhile, a method of encapsulating an organic light emitting diode according to the present invention comprises the steps of: (a) forming a first encapsulation layer on the surface of the organic light emitting diode by any one of a sputtering method, a thermal deposition method, a CVD method, ; (b) forming a second encapsulation film on the surface of the first encapsulation film by using any one of a sputtering method, a thermal deposition method, a CVD method, and an atomic layer deposition method using a polymeric material rather than a deposition material constituting the first encapsulating film And a step of

As described above, according to the sealing method of the organic light emitting diode according to the present invention, the double sealing film is deposited on the organic light emitting device by the CVD deposition method or the ALD deposition method, and the deposition rate is controlled as the homogeneous material or the heterogeneous material, Accordingly, the generation of a gap in the sealing film is completely suppressed, so that the organic thin film layer and the cathode layer of the organic light emitting diode are completely protected from oxygen or moisture.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a state in which a sealing film is deposited on a conventional organic light emitting device. FIG.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light-
FIG. 3 is a view showing a process of depositing an atomic or molecular sealant film by an atomic layer thin film apparatus. FIG.
FIGS. 4 to 8 are views schematically showing a state in which a sealing film is deposited on an organic light emitting device by a sealing method according to another embodiment of the present invention. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

≪ Embodiment 1 >

FIG. 2 is a schematic view illustrating a state in which a sealing film is deposited on an organic light emitting device by a sealing method according to a first embodiment of the present invention, and a method of forming a sealing film on the surface of the organic light emitting device .

As shown in the figure, the first encapsulation layer 20 is deposited to cover the anode layer, the organic thin film layer, and the cathode layer in the organic light emitting element 10.

The first encapsulation layer 20 may include a buffer layer, a planarization layer, and a passivation layer sequentially formed from the device side. The first encapsulation film 20 may be formed by depositing a metal oxide or nitride having excellent barrier properties against air and moisture by sputtering, thermal evaporation or CVD (Chemical Vapor Deposition) It can be deposited by one deposition method, and it is particularly preferable to deposit at a high deposition rate.

Meanwhile, a second encapsulation layer 20a is deposited on the first encapsulation layer 20 by an atomic layer deposition (ALD) method while the first encapsulation layer 100 is deposited .

The atomic layer deposition method is a method of forming a monolayer by chemical adsorption and desorption process by the surface saturated reaction of the reactive material at the surface of the device. It is a thin film deposition method capable of controlling the film thickness at the atomic layer level to be.

When the second sealing film 20a is deposited on the first sealing film 20 by the atomic layer deposition process as described above, two or more source gases (the source gas and the source gas) And a purge gas, which is an inert gas, is introduced between the inflow of the source gases, whereby the source gases react on the surface of the first encapsulant to form a predetermined thin film. That is, when one source gas (source gas) is chemically adsorbed on the surface of the first sealing film and subsequently another source gas (reaction gas) is provided, the two source gases chemically react on the surface One atomic layer is formed on the surface of the first sealing film.

Then, the second sealing film 20a having a predetermined thickness may be deposited repeatedly until the thin film having a desired thickness is formed at such a cycle.

At this time, when the second sealing film 20a is deposited by the atomic layer deposition method, the deposition is performed at a slower rate than when the first sealing film 20 is deposited.

As described above, when the second sealing film 20a, which is a thin film of atomic or molecular units, is deposited on the first sealing film 20 by the atomic layer deposition method, the gaps that can be formed in the first sealing film 20 are all As a result, oxygen and moisture are completely prevented from penetrating into the cathode and the organic thin film layer of the organic light emitting element 10.

≪ Embodiment 2 >

FIG. 4 is a schematic view illustrating a state in which a sealing film is deposited on an organic light emitting device by a sealing method according to a second embodiment of the present invention, and a method of sealing the organic light emitting device will be described with reference to FIG.

As shown in the figure, the first encapsulation layer 20 is deposited to cover the anode layer, the organic thin film layer, and the cathode layer in the organic light emitting element 10.

The first encapsulation layer 20 may include a buffer layer, a planarization layer, and a passivation layer sequentially formed from the device side. The first encapsulation film 20 may be formed by depositing a metal oxide or nitride having excellent barrier properties against air and moisture by sputtering, thermal evaporation or CVD (Chemical Vapor Deposition) It is possible to deposit by one deposition method, and it is particularly preferable to perform deposition at a high deposition rate.

On the other hand, in the state that the first encapsulation film 100 is deposited, a second encapsulation film 20b is deposited on the first encapsulation film 20.

The second encapsulation layer 20b may be formed of any one of a sputtering method, a thermal evaporation method, and a CVD (Chemical Vapor Deposition) method using a metal oxide or nitride having an excellent barrier property against air and moisture. And in this case, deposition is performed at a slow deposition rate as compared with the first encapsulation film 20. In this case,

When the second encapsulation film 20b is deposited at a slow deposition rate on the first encapsulation film 20, the amorphous or polymer crystal itself is enlarged. As a result, the first encapsulation film 20b is deposited at a high deposition rate, The sealing film 20 is completely covered and the gap is blocked.

Accordingly, the gaps that can be formed in the first sealing film 20 are completely filled, and oxygen and moisture are completely blocked from penetrating into the cathode and the organic thin film layer of the organic light emitting element 10.

≪ Third Embodiment >

5 and 6 are views schematically showing a state in which a sealing film is deposited on an organic light emitting device according to a third embodiment of the present invention, and a method of sealing the surface of the organic light emitting device will be described with reference to FIG. .

As shown in the figure, the first encapsulation layer 20 is deposited to cover the anode layer, the organic thin film layer, and the cathode layer in the organic light emitting element 10.

The first encapsulation layer 20 may include a buffer layer, a planarization layer, and a passivation layer sequentially formed from the device side. The first encapsulation film 20 may be formed by depositing a metal oxide or nitride having excellent barrier properties against air and moisture by sputtering, thermal evaporation or CVD (Chemical Vapor Deposition) Can be deposited by one deposition method, in particular, deposition at a slow deposition rate.

On the other hand, in the state that the first encapsulation film 20 is deposited, the second encapsulation film 30 is deposited on the first encapsulation film 20.

The second sealing film 30 may also be formed by sputtering, thermal evaporation or CVD (Chemical Vapor Deposition) or atomic layer deposition (e.g., sputtering, thermal evaporation, or chemical vapor deposition) The deposition may be performed by any one of deposition methods. In this case, deposition is preferably performed at a deposition rate that is faster than that of the first sealing film 20.

As the first encapsulation layer 20 is deposited at a slow deposition rate and the first encapsulation layer 20 forms a buffer layer or an interface activation layer, (30) is deposited at a high deposition rate, it is deposited as an excellent thin film, thereby preventing the occurrence of gaps.

<Fourth Embodiment>

7 and 8 are schematic views illustrating a state in which a sealing film is deposited on an organic light emitting diode according to a fourth embodiment of the present invention. Referring to FIG. 7, a method of sealing the surface of the organic light emitting diode will be described as follows .

A metal oxide or nitride having excellent barrier properties against air and moisture is formed on the surface of the organic light emitting element 10 by sputtering, thermal evaporation or CVD (Chemical Vapor Deposition) ) Or an atomic layer deposition method, a metal oxide or nitride having excellent barrier properties against air and moisture is formed on the first seal films 20 and 30 by a sputtering method ( the second encapsulation films 30 and 20 are formed by any one of vapor deposition, sputtering, thermal evaporation, CVD (Chemical Vapor Deposition) and atomic layer deposition.

The first and second sealing films 20 and 30 and the second sealing films 30 and 20 are made of a different material than the first sealing films 20 and 30, . Since the first encapsulation films 20 and 30 and the second encapsulation films 30 and 20 are deposited using the different materials, the step coverage is improved, and the formation of the gap is prevented by the deposition of the excellent film.

7, the first encapsulation layer 20 may be formed by an atomic layer deposition method and the second encapsulation layer 30 may be formed by sputtering, thermal evaporation, or CVD The first encapsulation layer 30 may be formed by a sputtering method, a thermal evaporation method or a CVD method (Chemical Vapor Deposition), as shown in FIG. Deposition), and the second sealing film 20 may be formed by an atomic layer deposition method.

The technical ideas described in the embodiments of the present invention as described above may be independently performed, or may be implemented in combination with each other. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. It is possible. Accordingly, the technical scope of the present invention should be determined by the appended claims.

10: organic light emitting element 20: first sealing film
20, 20a, 20b, 30: second sealing film

Claims (5)

(a) forming a first sealing film on a surface of an organic light emitting device at a predetermined deposition rate by using any one of a sputtering method, a thermal evaporation method, and a CVD method;
(b) forming a second sealing film on the surface of the first sealing film at a rate that is relatively slower than the predetermined deposition rate by using any one of a sputtering method, a thermal evaporation method, and a CVD method to form an amorphous or polymer crystal And filling the gap (gap) that can be formed in the first sealing film with oxygen and moisture to prevent the penetration into the organic light emitting device.
delete (a) forming a first sealing film on a surface of an organic light emitting device at a predetermined deposition rate by using any one of a sputtering method, a thermal evaporation method, and a CVD method;
(b) an atomic layer deposition method by chemical reaction of one source gas and one source gas (reaction gas) on the surface of the first encapsulant, And forming a second sealing film which is a thin film so as to prevent oxygen and moisture from permeating into the organic light emitting element as the gaps (gaps) that can be formed in the first sealing film are filled, A method of encapsulating a light emitting element. delete delete

Images