JP2009245734A - Organic el element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element which can control breakage caused by peeling-off or the like between a cathode electrode and an organic light-emitting layer. <P>SOLUTION: The organic EL element 1 includes an element substrate 2, an anode electrode 3 formed on the element substrate 2, the organic light-emitting layer 4 formed on the anode electrode 3, the cathode electrode 5 made of an aluminum film formed on the organic light-emitting layer 4, a first mitigation layer 6 made of an organic substance NPD and formed on the cathode electrode 5, a second mitigation layer 7 made of an aluminum film and formed on the first mitigation layer 6, and a solid sealing resin layer 8 containing a UV-cured resin and formed on the second mitigation layer 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic EL (electroluminescence) element provided with a solid sealing resin layer made of a curable resin such as a UV curable resin.

  Conventionally, an organic EL element having an organic light emitting layer is known. In Patent Document 1, an element substrate, an anode electrode formed on the element substrate, an organic light emitting layer formed on the anode electrode, a cathode electrode formed on the organic light emitting layer, and a cathode electrode are formed. An organic protective film made of para-xylene resin, an inorganic protective film made of cerium dioxide formed on the organic protective film, a solid sealing resin layer made of UV curable resin formed on the inorganic protective film, and UV An organic EL device including a sealing plate disposed on a cured resin is disclosed.

  In the organic EL element of Patent Document 1, when voltage is applied to the anode electrode and the cathode electrode, holes are injected from the anode electrode to the organic light emitting layer, and electrons are injected from the cathode electrode to the organic light emitting layer. The injected holes and electrons recombine in the organic light emitting layer to emit light.

In the method of manufacturing an organic EL element of Patent Document 1, an anode electrode, an organic light emitting layer, a cathode electrode, an organic protective film, and an inorganic protective film are sequentially laminated on an element substrate. Next, a UV adhesive is applied on the inorganic protective film. Thereafter, UV irradiation is performed with the sealing plate placed on the UV adhesive. Thereby, the UV adhesive is cured and the element substrate and the sealing plate are sealed.
JP 2000-68049 A

  However, the organic EL element of Patent Document 1 expands and contracts when the UV adhesive is cured. The stress due to the expansion / contraction of the UV adhesive is transmitted to the cathode electrode through the inorganic protective film and the organic protective film. As a result, there is a problem such as damage due to peeling between the cathode electrode and the organic light emitting layer.

  The present invention has been made in order to solve the above-described problems, and an object thereof is to provide an organic EL element capable of suppressing breakage.

  In order to achieve the above object, an invention according to claim 1 includes an element substrate, a first electrode formed on the element substrate, an organic light emitting layer formed on the first electrode, and the organic A second electrode formed on the light emitting layer, a first relaxing layer made of an insulator or an organic material formed on the second electrode, and a second relaxing layer made of a metal formed on the first relaxing layer And a solid encapsulating resin layer containing a cured resin formed on the second relaxation layer.

  The invention according to claim 2 is the organic EL element according to claim 1, wherein the first relaxation layer and the organic light emitting layer contain the same material.

  The invention according to claim 3 is characterized in that the second electrode and the second relaxation layer contain the same material, and the organic EL element according to claim 1 or 2. It is.

  The invention according to claim 4 is the organic EL element according to any one of claims 1 to 3, wherein the second relaxation layer is thicker than the first relaxation layer. is there.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein a plurality of the first relaxing layers and the second relaxing layers are alternately stacked. This is an organic EL element.

  The invention according to claim 6 is the organic EL element according to any one of claims 1 to 5, wherein the second electrode is made of metal.

  According to the present invention, between the second electrode and the solid encapsulating resin layer, the first relaxation layer made of an insulating material or an organic material and the second relaxation layer made of a metal having weak adhesion at the interface are provided. Yes. Thereby, the stress resulting from the expansion and contraction when the cured resin is cured can be broken between the first relaxation layer and the second relaxation layer. As a result, it can suppress that a stress acts on a 2nd electrode, and can suppress the damage resulting from peeling etc. with a 2nd electrode and an organic light emitting layer.

(First embodiment)
Hereinafter, an organic EL device according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an organic EL element according to the first embodiment. In the following description, the top and bottom indicated by the arrows in FIG.

  As shown in FIG. 1, the organic EL element 1 according to the first embodiment includes an element substrate 2, an anode electrode 3, an organic light emitting layer 4, a cathode electrode 5, a first relaxation layer 6, and a second relaxation layer. 7, a solid sealing resin layer 8, and a sealing plate 9.

  The element substrate 2 is made of a glass substrate having a thickness of about 0.5 mm and capable of transmitting light. The lower surface of the element substrate 2 is a light extraction surface 2 a for extracting light emitted by the organic light emitting layer 4. The upper surface of the element substrate 2 is a main surface 2b on which the layers 3 to 7 are stacked.

  The anode electrode 3 is for injecting holes into the organic light emitting layer 4. The anode electrode 3 is formed on the main surface 2 b of the element substrate 2. The anode electrode 3 is made of ITO (indium tin oxide) having a thickness of about 100 nm capable of transmitting light.

The organic light emitting layer 4 is for emitting white light. The organic light emitting layer 4 is formed on the anode electrode 3 in an electrically connected state. In the organic light emitting layer 4, a hole transport layer and an electron transport layer are laminated in order from the anode electrode 3 side. The hole transport layer is made of an NPD (diphenylnaphthyldiamine) film having a thickness of about 50 nm. The electron transport layer is made of a quinolinol aluminum complex (Alq ₃ ) film having a thickness of about 50 nm and mixed with a dye. Further, copper phthalocyanine (CuPc) may be laminated between the anode electrode 3 and the organic light emitting layer 4 in order to promote hole injection from the anode electrode 3.

  The cathode electrode 5 is for injecting electrons into the organic light emitting layer 4. The cathode electrode 5 is formed on the organic light emitting layer 4 in an electrically connected state. The cathode electrode 5 is made of an Al film having a thickness of about 100 nm. The cathode electrode 5 is insulated from the anode electrode 3 by an insulating film (not shown).

  The first relaxing layer 6 and the second relaxing layer 7 protect the anode electrode 3, the organic light emitting layer 4, and the cathode electrode 5, and also relieve stress generated when the solid sealing resin layer 8 is cured. is there.

The first relaxation layer 6 is formed on the cathode electrode 5. The first relaxing layer 6 is made of NPD having a thickness of about 100 nm. The thickness of the first relaxation layer 6 is not limited to about 100 nm, but is preferably 10 nm or more in order to relax the stress caused by the solid sealing resin layer 8. Here, since the first relaxing layer 6 is made of NPD which is an organic substance, the first relaxing layer 6 is easily peeled off from the cathode electrode 5 made of metal due to weak adhesion. The material constituting the first relaxing layer 6 is not limited to NPD, and other organic substances can be used. However, from the viewpoint of simplifying the manufacturing process, the material constituting the first relaxing layer 6 is preferably the same material as any of the materials constituting the organic light emitting layer 6. Furthermore, it may be the first relief layer 6 constituted by _SiO 2, inorganic insulating material such as SiN.

  The second relaxing layer 7 is formed on the first relaxing layer 6. The second relaxation layer 7 is made of an Al film having a thickness of about 500 nm. Although the thickness of the second relaxation layer 7 is not limited to a thickness of about 500 nm, it is preferably 20 nm or more in order to relax the stress caused by the solid sealing resin layer 8. Here, since the 2nd relaxation layer 7 consists of Al which is a metal, it adheres with the 1st relaxation layer 6 which consists of organic substance weakly, and peels easily.

  The solid sealing resin layer 8 is for sealing the sealing plate 9 on the second relaxing layer 7. The solid sealing resin layer 8 is made of an epoxy UV curable resin. In addition, you may comprise the solid sealing resin layer 8 with curable resins, such as a thermosetting resin.

  The sealing plate 9 is made of a glass substrate having a thickness of about 0.5 mm. The sealing plate 9 is sealed on the second relaxing layer 7 by the solid sealing resin layer 8.

  Next, the operation of the organic EL element 1 according to the first embodiment described above will be described.

  First, in the organic EL element 1, a voltage is applied between the anode electrode 3 and the cathode electrode 5 by an external power source. As a result, holes are injected from the anode electrode 3 into the organic light emitting layer 4. Electrons are injected from the cathode electrode 5 into the organic light emitting layer 4. The injected holes and electrons recombine in the organic light emitting layer to emit light. The emitted light passes through the anode electrode 3 and the element substrate 2, and is then irradiated from the light extraction surface 2a.

  Next, a method for manufacturing the organic EL element 1 according to the first embodiment will be described. 2-4 is sectional drawing in each manufacturing process of an organic EL element.

  First, as shown in FIG. 2, the patterned anode electrode 3 is formed on the element substrate 2 by sputtering and lift-off. Thereafter, the organic light emitting layer 4 is deposited on the anode electrode 3 through a metal mask (not shown) in which an opening is formed. Furthermore, the patterned cathode electrode 5 is formed on the organic light emitting layer 4 by sputtering and lift-off.

Next, as shown in FIG. 3, a first relaxing layer 6 made of NPD is deposited on the cathode electrode 5 through a metal mask (not shown) in which openings are formed. When the first relaxing layer 6 is made of SiO ₂ or the like, it may be formed by sputtering. Thereafter, the patterned second relaxing layer 7 is formed on the first relaxing layer 6 by sputtering and lift-off. Next, a UV curable resin material 8 </ b> A is applied on the second relaxing layer 7. Thereafter, the sealing plate 9 is placed on the UV curable resin material 8A.

  Next, as shown in FIG. 4, the UV curable resin material 8 </ b> A is irradiated with ultraviolet rays through the sealing plate 9. Here, the UV curable resin material 8 </ b> A expands and contracts when it is cured to become the solid sealing resin layer 8. Due to this expansion and contraction, stress acts on the second relaxation layer 7 and the first relaxation layer 6. However, peeling occurs partially at the interface between the second relaxation layer 7 and the first relaxation layer 6 and at the interface between the first relaxation layer 6 and the cathode electrode 5, and the stress is broken.

  Then, the organic EL element 1 shown in FIG. 1 is completed by dividing into element units.

  As described above, the organic EL element 1 according to the first embodiment includes the first relaxation layer 6 and the second relaxation layer 7 between the cathode electrode 5 and the solid sealing resin layer 8. Here, the first relaxing layer 6 made of an organic material has weak adhesion to the cathode electrode 5 and the second relaxing layer 7 made of metal. As a result, the stress generated when the solid sealing resin layer 8 made of UV curable resin is cured is subjected to the interface between the first relaxation layer 6 and the second relaxation layer 7 and the interface between the first relaxation layer 6 and the cathode electrode 5. Can be broken. As a result, it is possible to suppress damage caused by the cathode electrode 5 being peeled off from the organic light emitting layer 4 due to stress, so that light emission defects can be reduced.

  In the organic EL element 1, the heat dissipation can be improved by making the second relaxing layer 7 thicker than the first relaxing layer 6.

  Further, in the organic EL element 1, by providing the first relaxing layer 6, the pressing force acting on the organic light emitting layer 4 can be relaxed even if a foreign matter mixed above the first relaxing layer 6 is pressed. it can.

  Moreover, in the organic EL element 1, the manufacturing process can be simplified by configuring the first relaxation layer 6 with the same NPD as the hole injection layer. In the organic EL element 1, the manufacturing process can be simplified by configuring the second relaxation layer 7 with the same Al as the cathode electrode 5.

(Second Embodiment)
Next, an organic EL element 1A according to a second embodiment in which the first embodiment described above is partially modified will be described. FIG. 5 is a cross-sectional view of an organic EL element according to the second embodiment. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment, and description is abbreviate | omitted.

As shown in FIG. 5, the organic EL device 1A according to the second embodiment includes first relaxation layers 6 ₁ , 6 ₂ , 6 ₃ ... And second relaxation layers 7 ₁ , 7 ₂ , 7 _3. A plurality of layers (for example, three layers) are periodically stacked alternately.

Thereby, the organic EL element 1A according to the second embodiment has an interface between each of the first relaxing layers 6 ₁ , 6 ₂ , 6 ₃ ... And each of the second relaxing layers 7 ₁ , 7 ₂ , 7 ₃ . The stress generated when the solid sealing resin layer 8 is cured can be broken. As a result, the transmission of stress to the cathode electrode 5 can be further suppressed.

  As mentioned above, although this invention was demonstrated in detail using embodiment, this invention is not limited to embodiment described in this specification. The scope of the present invention is determined by the description of the claims and the scope equivalent to the description of the claims. Hereinafter, modified embodiments in which the above-described embodiment is partially modified will be described.

  The materials, numerical values, shapes, and the like in the above-described embodiments are examples and can be changed as appropriate.

It is sectional drawing of the organic EL element by 1st Embodiment. It is sectional drawing in each manufacturing process of an organic EL element. It is sectional drawing in each manufacturing process of an organic EL element. It is sectional drawing in each manufacturing process of an organic EL element. It is sectional drawing of the organic EL element by 2nd Embodiment.

Explanation of symbols

1,1A organic EL element 2 element substrate 2a light extraction surface 2b main surfaces 3 anode electrode 4 organic light emitting layer 5 cathode electrodes ₆ 1, ... first relief layer _7,7 1, ... second relieving layer 8 Solid sealing resin layer 8A UV curable resin material 9 Sealing plate

Claims (6)

An element substrate;
A first electrode formed on the element substrate;
An organic light emitting layer formed on the first electrode;
A second electrode formed on the organic light emitting layer;
A first relaxation layer made of an insulating material or an organic material formed on the second electrode;
A second relaxation layer made of metal formed on the first relaxation layer;
An organic EL element comprising: a solid sealing resin layer containing a cured resin formed on the second relaxation layer.   The organic EL element according to claim 1, wherein the first relaxation layer and the organic light emitting layer contain the same material.   3. The organic EL device according to claim 1, wherein the second electrode and the second relaxation layer contain the same material. 4.   The organic EL element according to claim 1, wherein the second relaxation layer is thicker than the first relaxation layer.   5. The organic EL element according to claim 1, wherein a plurality of the first relaxation layers and the second relaxation layers are alternately stacked.   The organic EL device according to claim 1, wherein the second electrode is made of a metal.

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