KR20070047406A - Orgainc electroluminescent device having ultra-thin encapsulation structure including a getter layer - Google Patents

Abstract

Provided is an organic electroluminescent device capable of completely protecting a device from moisture while being able to be manufactured in an ultra-thin film. An organic electroluminescent device according to the present invention comprises a substrate; A plurality of pixels formed in an active region of the substrate; An encapsulation layer formed to cover at least an upper portion of the active region in which pixels are formed; And a getter layer formed on the encapsulation film.

Organic electroluminescent element, encapsulation film, getter layer

Description

An organic electroluminescent device having an ultra-thin encapsulation structure including a getter layer {ORGAINC ELECTROLUMINESCENT DEVICE HAVING ULTRA-THIN ENCAPSULATION STRUCTURE INCLUDING A GETTER LAYER}

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

1B is a schematic cross-sectional view of another conventional organic EL device.

2 is a schematic cross-sectional view of an organic EL device according to an exemplary embodiment of the present invention.

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

The present invention relates to an encapsulation structure of an organic electroluminescent device, and more particularly to an organic electroluminescent device having an ultra-thin encapsulation film containing a getter layer.

In organic electroluminescence, electrons and holes injected through a cathode and an anode are recombined to form an exciton in an organic (low molecular or polymer) thin film, and light of a specific wavelength is generated by energy from the excitons formed. This is a phenomenon that occurs. Referring to the structure of the organic EL device using this phenomenon as follows.

1A is a view schematically showing a conventional organic EL device.

Referring to FIG. 1A, an organic electroluminescent device 1 may be formed of indium tin oxide or metal formed by sputtering on an upper surface of a substrate 10 made of glass or film. An anode electrode layer 11 is formed, and an insulating film 12 is formed on the anode electrode layer 11.

Next, a barrier rib 13 is formed on the insulating layer 12 to intersect the anode electrode layer 11, and the barrier rib 13 serves to separate the cathode electrode layer 15 to be described later.

Next, an organic material layer 14 including an electron injection layer, an electron transporting layer, a light emitting layer, a hole transporting layer, and a hole injection layer is formed on the barrier 13 and the insulating layer 12, and a metal is formed on the organic material layer 14. The cathode electrode layer 15 of is formed.

In the organic electroluminescent element 1 thus formed, the cathode electrode 14 is generally formed of a highly reactive alloy system based on a material having a low work function, for example, alkali metals and alkaline earth metals. However, since it is easily oxidized by reacting with moisture, it causes a problem of deteriorating device characteristics or shortening device life. In addition, the organic material layer 14 formed below the cathode electrode layer 15 also tends to deteriorate under the influence of oxygen and moisture.

Therefore, the organic electroluminescent element 1 has an encapsulation structure in which a cap 16 made of glass or metal is adhered to the anode electrode layer 11 with a sealant S interposed therebetween. In addition, a getter (G), which is an absorbent, is attached to the bottom of the cap 16 through an adhesive tape, and the getter G collects moisture introduced from the outside through an adhesive part to maintain the device in a safe state. .

However, such a conventional organic electroluminescent device 1 having a metal or glass cap has an advantage of having an excellent shielding effect against oxygen and moisture, but this makes the overall thickness of the device thicker, thereby making it possible to display ultra-thin electronic devices. It has been pointed out that the device is difficult to realize.

In order to solve this problem, a method of encapsulating an organic electroluminescent element using an ultrathin film called an "encapsulation film" instead of a cap of glass or metal has been conventionally proposed.

1B is a view schematically showing another conventional organic EL device. The organic EL device shown in FIG. 1B is different only from the organic EL device and the encapsulation structure shown in FIG. 1A, and the remaining components are the same. Therefore, the same components are denoted by the same reference numerals.

Referring to FIG. 1B, the organic EL device 2 may include a substrate 10 of glass or film, an indium tin oxide or metal anode electrode layer 11 formed on the substrate 10, and an insulating layer formed on the anode electrode layer ( 12), a partition 13 formed on the insulating film and intersecting the anode electrode layer 11, an organic material layer 14 sequentially formed on the partition 13 and the anode electrode layer 11, and a cathode of a metal. The electrode layer 15, the organic material layer 14, the partition 13, and the multilayer encapsulation layers 17, 18, and 19 formed to cover all the electrode layers 11 and 15 are included.

The multilayer encapsulation films 17, 18, and 19 consist of a buffer layer 17, a planarization layer 18, and a passivation layer 19 formed sequentially from the substrate side.

The buffer layer 17 and the passivation layer 19 may be formed of a metal oxide or a nitride having excellent barrier ability to air and moisture by using a deposition technique such as CVD.

The planarization layer 18 serves to planarize the curvature of the organic layer 14 and the cathode electrode layer 15, and is formed using a polymer-based material.

The organic light emitting device 2 having such an ultra-thin film encapsulation structure has an advantage of being thin and suitable for adoption in ultra-thin portable electronic devices. There is still a need for a protective encapsulation structure.

Disclosure of Invention The present invention has been made to solve the above problems of the prior art, and an object thereof is to provide an organic electroluminescent device which can be manufactured in an ultra-thin film while completely protecting the device from moisture.

In order to achieve the above object, the organic electroluminescent device according to the present invention, the substrate; A plurality of pixels formed in an active region of the substrate; An encapsulation layer formed to cover at least an upper portion of the active region in which pixels are formed; And a getter layer formed on the encapsulation film.

In this case, the encapsulation film may be formed of a multilayer thin film including a buffer layer, a planarization layer, and a passivation layer.

In addition, a protective film may be further formed on the getter layer, and the protective film may be

It may be formed by laminating a polymer film, or may be formed by depositing silicon nitride or silicon oxide.

In the present invention, the getter layer may be formed by applying a liquid slurry in which the getter material is mixed with a binder, and the getter material may be barium, calcium, barium oxide, or calcium oxide. ) Or a polyacrylonitrile-based superabsorbent polymer material may be used. At this time, a thermosetting resin or an ultraviolet curable resin may be used as the binder. As the binder, a resin which can be naturally cured without irradiating ultraviolet rays or applying heat can also be used.

In the present invention, the getter layer may be formed by depositing a getter material in the form of a thin film. In this case, a getter material may be a material selected from alkali metals, alkaline earth metals or oxides thereof. In addition, as a method of depositing a getter layer, sputtering, thermal evaporation, or CVD can be used.

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

2 is a schematic cross-sectional view of an organic EL device according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the organic EL device 3 includes a transparent substrate 31 made of glass or film, and an active region in which a plurality of pixels are formed is formed on the substrate 31.

The active region includes an anode electrode layer 32 made of indium tin oxide or a metal, an insulating film 33 formed on the anode electrode layer 32, and a partition wall formed on the insulating film 33 and crossing the anode electrode layer 32. (34), the organic material layer 35 and the metal cathode electrode layer 36 formed sequentially on the partition 34 and the anode electrode layer 32 are formed.

The organic layer 35 is a multilayer structure in which a hole transport layer, a light emitting layer, and an electron transport layer are stacked, and different types of organic materials must be deposited for each of R, G, and B light emitting regions. Although a single organic material layer 35 and a cathode electrode layer 36 are shown between the two partition walls 33 in FIG. 2, an organic material layer and a cathode electrode layer having the same structure are formed on both sides thereof to form R, G, and B light emitting regions. Of course they form.

The encapsulation layers 37a, 37b, and 37c covering the organic layer 35, the partition 34, and the electrode layers 32 and 36 are formed on the active region.

The encapsulation films 37a, 37b, and 37c may be formed of a multilayer thin film in which the buffer layer 37a, the planarization layer 37b, and the passivation layer 37c are sequentially formed from the substrate side.

The buffer layer 37a is formed by depositing a metal oxide or nitride having excellent barrier ability against air and moisture in the form of a thin film.

Preferably, the buffer layer 37a is made of a thin film of silicon nitride such as SiN _x or silicon oxide such as SiO ₂ by sputtering or CVD. The thickness of the said thin film is 5 micrometers or less, Preferably it is 2 micrometers or less.

The planarization layer 37b serves to planarize the bend in the organic material layer and the cathode electrode layer formed thereunder, and may be formed using a polymer-based material.

Preferably, the planarization layer 37b is formed of a nonconductive organic film such as BenzoCyclo-Butene (BCB) or Seal (Dow Chemical Company brand, SiLK).

Like the buffer layer 37a, the passivation layer 37c is formed by depositing a metal oxide or nitride having excellent barrier ability against air and moisture in the form of a thin film.

Preferably, the passivation layer 37c is made of a thin film of silicon nitride such as SiN _x or silicon oxide such as SiO ₂ by sputtering or CVD. The thickness of the said thin film is 5 micrometers or less, Preferably it is 2 micrometers or less.

In accordance with an aspect of the present invention, a getter layer 38 is formed on at least the encapsulation layers 37a, 37b, and 37c formed to cover the active region. The getter layer 38 collects moisture or gas that penetrates from the external environment and prevents them from penetrating the encapsulation films 37a, 37b, and 37c and into the inside of the device.

The getter layer 38 may be formed by applying a liquid slurry containing a getter material on top of the encapsulation films 37a, 37b, and 37c.

The liquid slurry is a moisture-absorbing, oxygen-absorbing or NO _x absorbing getter material, for example barium (calcium), barium oxide (barium oxide), or powder of calcium oxide (calcium oxide) to the resin binder, For example, it may be prepared by mixing with a thermosetting resin such as phenol resin, urea resin, polyester or ultraviolet curable resin such as silicone, epoxy, acrylic, urethane. As the binder, a resin which can be naturally cured without irradiating ultraviolet rays or applying heat can also be used.

In addition, the liquid slurry is a high-hygroscopic polymer material having a property of absorbing oxygen and moisture, for example, polyacrylonitrile-based resin powder binders, for example, thermosetting resin such as phenol resin, urea resin, polyester or silicone It can be produced by mixing with ultraviolet curable resins such as epoxy, acrylic, urethane. As the binder, a resin which can be naturally cured without irradiating ultraviolet rays or applying heat can also be used.

In the present embodiment, the liquid slurry is applied to the entire upper region of the encapsulation films 37a, 37b, and 37c so that the getter layer 38 can react with oxygen and moisture in a large area. It may be formed only on a portion of the encapsulation films 37a, 37b, 37c in consideration of the path.

The getter layer 38 according to the present embodiment may be deposited on top of the encapsulation films 37a, 37b, and 37c in a thin film using a deposition technique, in addition to the method of manufacturing and applying the liquid slurry as described above. have.

As the getter material, a metal material having good reactivity with moisture or oxygen, for example, an alkali metal, an alkaline earth metal or an oxide thereof may be used. Preferably the metal material is a metal such as barium or zirconium, more preferably the metal material is barium.

As a deposition method for depositing the getter material as a thin film on the encapsulation films 37a, 37b and 37c, for example, a deposition method such as sputtering, thermal evaporation or CVD may be used. . However, it is not necessarily limited to these methods, and any deposition method suitable for forming a metal thin film may be used.

It is important that the thin film forming the getter layer 38 is formed to a thickness that does not affect the overall thickness of the device. Preferably, the thickness of said thin film is 20 micrometers or less, More preferably, the thickness of the said thin film is 10 micrometers or less, Most preferably, it is 5 micrometers or less.

3 is a cross-sectional view schematically showing an organic light emitting device according to another embodiment of the present invention. This embodiment is distinguished from the embodiment shown in FIG. 2 in that a protective film for protecting the getter layer from the outside is further formed on the getter layer. Therefore, use the same protection for the same parts.

Referring to FIG. 3, the organic electroluminescent device 4 includes a transparent substrate 31 made of glass or film, and an active region in which a plurality of pixels are formed is formed on the substrate 31.

The active region includes an anode electrode layer 32 made of indium tin oxide or a metal, an insulating film 33 formed on the anode electrode layer 32, and a partition wall formed on the insulating film 33 and crossing the anode electrode layer 32. (34), the organic material layer 35 sequentially formed on the partition 34 and the anode electrode layer 32 and the cathode electrode layer 36 of metal are formed, the specific configuration of which is the configuration of the previously described embodiment Is the same as

Encapsulation films 37a, 37b, and 37c are formed on the active region in which the organic material layer 35, the partition wall 34, and the electrode layers 32 and 36 are formed. The encapsulation films 37a, 37b, 37c are composed of a multilayer thin film in which a buffer layer 37a, a planarization layer 37b, and a passivation layer 37c are sequentially formed from the substrate side, and their configurations are similar to those of the previously described embodiment. Since it is the same, it is not repeated.

In accordance with an aspect of the present invention, a getter layer 38 is formed on the encapsulation films 37a, 37b, and 37c. The getter layer 38 collects moisture or gas that penetrates from the external environment and prevents them from penetrating the encapsulation films 37a, 37b, and 37c and into the inside of the device.

The getter layer 38 may be formed by applying a liquid slurry containing a getter material on top of the encapsulation films 37a, 37b, and 37c.

The liquid slurry is a moisture-absorbing, oxygen-absorbing or NO _x absorbing getter material, for example barium (calcium), barium oxide (barium oxide), or powder of calcium oxide (calcium oxide) to the resin binder, For example, it may be prepared by mixing with a thermosetting resin such as phenol resin, urea resin, polyester or ultraviolet curable resin such as silicone, epoxy, acrylic, urethane. As the binder, a resin which can be naturally cured without irradiating ultraviolet rays or applying heat can also be used.

In addition, the liquid slurry is a high-hygroscopic polymer material having a property of absorbing oxygen and moisture, for example, polyacrylonitrile-based resin powder binders, for example, thermosetting resin such as phenol resin, urea resin, polyester or silicone It can be produced by mixing with ultraviolet curable resins such as epoxy, acrylic, urethane. As the binder, a resin which can be naturally cured without irradiating ultraviolet rays or applying heat can also be used.

In the present embodiment, the liquid slurry is applied to the entire upper region of the encapsulation films 37a, 37b, and 37c so that the getter layer 38 can react with oxygen and moisture in a large area. It may be formed only on a portion of the encapsulation films 37a, 37b, 37c in consideration of the path.

The getter layer 38 according to the present embodiment may be deposited on top of the encapsulation films 37a, 37b, and 37c in a thin film using a deposition technique, in addition to the method of manufacturing and applying the liquid slurry as described above. have.

As the getter material, a metal material having good reactivity with moisture or oxygen, for example, an alkali metal, an alkaline earth metal or an oxide thereof may be used. Preferably the metal material is a metal such as barium or zirconium, more preferably the metal material is barium.

As a deposition method for depositing the getter material as a thin film on the encapsulation films 37a, 37b and 37c, for example, a deposition method such as sputtering, thermal evaporation or CVD may be used. . However, it is not necessarily limited to these methods, and any deposition method suitable for forming a metal thin film may be used.

It is important that the thin film forming the getter layer 38 is formed to a thickness that does not affect the overall thickness of the device. Preferably, the thickness of said thin film is 20 micrometers or less, More preferably, the thickness of the said thin film is 10 micrometers or less, Most preferably, it is 5 micrometers or less.

The passivation layer 39 that protects the getter layer is formed on the getter layer 38. The protective film 39 is formed not only to prevent moisture or the like from directly contacting the getter layer 38 from the outside, but also to prevent the coating film of the getter layer 38 from peeling off due to a physical impact applied from the outside.

The protective film 39 may be any material as long as it can perform the above purpose.

For example, the passivation layer 39 may be made of a thin film using the same material as that of the buffer layer 37a or the passivation layer 37c formed thereunder. In this case, the protective film 39 may be made of a thin film of silicon nitride such as SiN _x or silicon oxide such as SiO ₂ by the sputtering method or the CVD method.

In addition, in order to simplify the process, it is also possible to form the protective film 39 in a manner in which the polymer film in the form of a sheet is laminated by a known laminating technique, that is, the polymer film in the form of a sheet is heated to a predetermined temperature and compressed by a roller.

According to the present invention, since the getter layer in the form of a thin film covers the sealing film of the ultra-thin film and reliably protects the internal device from external moisture, there is an advantage that it can be stored and used for a long time regardless of the use environment.

In addition, according to the present invention, since the getter layer in the form of a thin film blocks moisture that penetrates into the encapsulation film, it is not necessary to form an encapsulation film in an excessively multilayered manner, thereby making it possible to manufacture an ultra-thin organic EL device.

Claims (17)

Board; A plurality of pixels formed in an active region of the substrate; An encapsulation layer formed to cover at least an upper portion of the active region in which pixels are formed; And An organic electroluminescent device comprising a getter layer formed on the encapsulation film. The method of claim 1, The encapsulation film is an organic electroluminescent device, characterized in that consisting of a multilayer thin film comprising a buffer layer, a planarization layer and a passivation layer. The method of claim 2, The buffer layer is an organic electroluminescent device, characterized in that made of silicon oxide or silicon nitride. The method of claim 2, The planarization layer is an organic electroluminescent device, characterized in that the non-conductive organic film. The method of claim 2, The passivation layer is an organic electroluminescent device, characterized in that made of silicon oxide or silicon nitride. The method according to any one of claims 1 to 5, An organic electroluminescent device, further comprising a protective film formed on the getter layer. The method of claim 6, The protective film is an organic electroluminescent device, characterized in that formed by laminating a polymer film. The method of claim 6, The protective film is an organic electroluminescent device, characterized in that formed by depositing silicon nitride or silicon oxide. The method of claim 1, The getter layer is formed by applying a liquid slurry obtained by mixing a getter material with a binder. The method of claim 9, The getter material is an organic electroluminescent device, characterized in that selected from barium (calcium), barium oxide (barium oxide), or calcium oxide (calcium oxide). The method of claim 9, The getter material is an organic electroluminescent device, characterized in that the polyacrylonitrile-based superabsorbent polymer material. The method of claim 9, The binder is an organic electroluminescent device, characterized in that the thermosetting resin or ultraviolet curable resin. The method of claim 9, The binder is an organic electroluminescent device, characterized in that the resin that can be naturally cured. The method of claim 1, The getter layer is formed by depositing a getter material in the form of a thin film. The method of claim 14, The getter material is an organic electroluminescent device, characterized in that the material selected from alkali metal, alkaline earth metal or oxides thereof. The method of claim 14, And the getter material is barium or zirconium. The method according to any one of claims 14 to 16, The getter layer is formed by any one of sputtering, thermal evaporation, or CVD method.

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