JP2007141645A - Organic el display panel and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL display panel preventing an organic light emitting layer from intrusion of moisture, not damaging light emitting property of pixels and life, and a manufacturing method of the same. <P>SOLUTION: An organic light emitting layer 7 and a cathode 8 are arranged so as to run on an end part of an insulation layer 6. A coating film layer 12 is formed in large size so as to cover the organic light emitting layer 7 and the cathode 8 up to outside thereof, and end part of the film layer contacts the side face of barrier ribs 9. By the above, end part of the organic light emitting layer 7 and the cathode 8 are completely covered by the coating film layer 12 made of metallic material or the like, and end face or the like is not exposed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic EL display panel and a manufacturing method thereof.

  An organic EL (electroluminescence) display panel includes an organic EL element substrate having an organic light emitting layer sandwiched between an anode electrode and a cathode electrode, and a sealing substrate facing the organic EL element substrate. It is sealed with a sealing material such as an ultraviolet curable resin disposed on the outer periphery of the resin.

  In the organic EL element substrate constituting the organic EL display panel, on one surface of the anode electrode, for example, an insulating layer partitioned in a lattice shape in which a plurality of rectangular regions corresponding to pixels are arranged is formed. The organic light-emitting layer covering one surface of the anode electrode and a part of the insulating layer and the cathode electrode are sequentially laminated.

By the way, this organic light emitting layer causes deterioration of characteristics even when water penetrates slightly, and causes a decrease in luminance, a reduction in pixels due to enlargement of a non-light emitting portion called a dark frame, or a decrease in the life of an organic EL display panel. Cause it to occur. For this reason, it is required to have a structure that does not allow moisture to penetrate into the organic light emitting layer.
JP 2001-296819 A

  In a conventional organic EL element substrate, an organic light emitting layer is laminated on each rectangular area on an anode electrode partitioned by an insulating layer by vapor deposition or the like, and then a cathode electrode made of a material that does not penetrate water is laminated to produce organic light emission. By covering the layer, the organic light emitting layer was prevented from penetrating moisture.

  However, in the conventional organic EL element substrate, the organic light emitting layer and the cathode electrode are formed in substantially the same size. For this reason, the side edge (edge part) of the organic light emitting layer is not completely covered with the cathode electrode, but an exposed part is generated, and the junction between the insulating layer and the organic light emitting layer is formed from the side edge of the organic light emitting layer. In this case, there is a problem that moisture penetrates into the organic light emitting layer by capillary action or diffusion.

  The present invention has been made in view of the above circumstances, and provides an organic EL display panel that prevents moisture from penetrating into the organic light emitting layer and does not impair the light emission characteristics and life of the pixel, and a method for manufacturing the same. For the purpose.

  In order to achieve the above object, according to the present invention, a step of forming an insulating layer that divides one surface of an anode electrode into a plurality of rectangular regions, and a surface of the anode electrode and a part of the insulating layer are covered. Forming a plurality of organic light emitting layers as described above, forming a cathode electrode so as to cover at least a part of the organic light emitting layer, and extending outside the peripheral edges of the organic light emitting layer and the cathode electrode, Forming a coating layer that covers the organic light emitting layer and the cathode electrode to the end, and performing the step of forming the cathode electrode by a vapor deposition method and performing the step of forming the coating layer by a sputtering method. An organic EL display panel manufacturing method is provided.

The sputtering method for forming the coating layer may use a rare gas as a sputtering gas in a pressure range of 200 to 1 × 10 ⁻² Pa.

  According to the present invention, an insulating layer that divides one surface of the anode electrode into a plurality of rectangular regions, a plurality of organic light emitting layers that cover one surface of the anode electrode and a part of the insulating layer, and the organic light emitting layer A plurality of cathode electrodes covering at least a part of the organic light-emitting layer, and a coating layer extending to the outside of the organic light-emitting layer and the periphery of the cathode electrode and covering the organic light-emitting layer and the cathode electrode to the end. An organic EL display panel is provided.

  A partition wall rising from the insulating layer may be further formed between the cathode electrodes adjacent to each other. Moreover, the edge part of the said film layer should just be in contact with the said partition.

  According to the method for producing an organic EL display panel of the present invention, a film layer is formed by sputtering on an organic light-emitting layer and a cathode electrode formed by vapor deposition, for example, the root portion of an inverted triangular partition. In this method, the coating layer is formed up to a portion that is difficult to stack, and it is possible to completely prevent the penetration of moisture into the organic light emitting layer without exposing the end face of the organic light emitting layer. Thereby, it is possible to reliably prevent moisture from penetrating from the end face of the organic light emitting layer to the back of the organic light emitting layer along the interface with the insulating layer, which has been a conventional problem.

  Even if there is moisture that could not be completely captured by the water trapping material, etc., it would not penetrate the organic light-emitting layer, and the organic light-emitting layer would deteriorate characteristics due to the penetration of water, and non- It is possible to effectively prevent the occurrence of problems such as a decrease in luminance, a reduction in pixels, or a decrease in the lifetime of the organic EL display panel due to the enlargement of the light emitting portion.

  Hereinafter, an organic EL display panel according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of an organic EL display panel according to this embodiment. An organic EL display panel 1 includes an organic EL element substrate 2, a sealing substrate 3 facing the organic EL element substrate 2, a sealing material 4 for sealing the organic EL elements by bonding these substrates, and an organic EL element substrate 2, a water catching material 5 provided in a sealed space formed by the sealing substrate 3 and the sealing material 4.

  The organic EL element substrate 2 is made of, for example, a transparent glass substrate having a thickness of 0.4 to 1.1 mm, and a plurality of transparent strip-like anode electrodes 11 such as ITO are formed thereon. The lower side 10 of the organic EL element substrate 2 corresponds to a so-called viewing side.

  On the anode electrode 11, organic light emitting layers 7, 7... Serving as a light source, cathode electrodes 8, 8... Made of a metal material such as aluminum, insulating layers 6, 6. The organic light emitting layer 7 is sandwiched between the anode electrode 11 and the cathode electrode 8 so that a current can be applied. On the cathode electrode 8, for example, coating layers 12, 12,... Made of the same metal material as the cathode electrode 8 are formed. On the insulating layers 6, 6..., Partition walls 9, 9.

  The sealing substrate 3 is made of, for example, glass or acrylic resin, and is provided so as to cover the organic EL element substrate 2. Further, the shape of the sealing substrate 3 is such that a convex portion is provided on the outer peripheral portion of the substrate on the flat plate, and this convex portion is joined to the organic EL element substrate 2 via the sealing material 4. As a result, the organic EL element is sealed.

  The sealing material 4 is made of, for example, an epoxy-based or acrylic-based ultraviolet curable resin. Among these, a resin having low water permeability is preferable from the viewpoint of preventing moisture from entering from the outside.

  A water catching material 5 is provided over the entire surface of the sealing substrate 3 surrounded by the convex portions. The water catching material 5 may be provided not on the entire surface of the sealing substrate 3 surrounded by the convex portions but on a part thereof. However, in order to increase the water catching efficiency in the panel, it is preferably provided over the entire surface. . The water catching material is a material having a water catching function mixed with a viscous inert solvent or a resin, and examples of the material having a water catching function include zeolite, alumina, Examples include physical adsorption type such as silica gel and molecular sieve, and chemical adsorption type such as calcium oxide, barium oxide, magnesium oxide, sodium sulfate, calcium sulfate, and titanium sulfate.

  FIG. 2 is a partial enlarged cross-sectional view of the organic EL element substrate. In the organic EL display panel 1, for example, one pixel region P is formed between the insulating layers 6, 6. In the pixel region P, the organic light emitting layer 7 is caused to emit light by applying a current to the organic light emitting layer 7 sandwiched between the anode electrode 11 and the cathode electrode 8. The pixel region P is partitioned by the insulating layer 6 and becomes a grid-like rectangular region. That is, the insulating layer 6 is laminated on the anode electrode 11, and a rectangular opening is formed at a position corresponding to the pixel region P. The organic light emitting layer 7 and the cathode electrode 8 are laminated in this opening.

  Outside the pixel region P, the organic light emitting layer 7 and the cathode electrode 8 are formed so as to run over the end of the insulating layer 6. The coating layer 12 is formed to be larger than the organic light emitting layer 7 and the cathode electrode 8, and the end portion is in contact with the side surface of the partition wall 9. That is, the end portions of the organic light emitting layer 7 and the cathode electrode 8 are completely covered with the coating layer 12 formed of a metal material or the like, and the end surfaces are not exposed.

  As described above, the organic light emitting layer 7 and the cathode electrode 8 are completely covered up to the end portions by the coating layer 12 formed of a material having no water permeability such as a metal film. Thus, it is possible to reliably prevent moisture from penetrating into the organic light emitting layer along the interface with the insulating layer 6.

  As a result, even if there is moisture that cannot be completely captured by the water catching material 5, it does not penetrate into the organic light emitting layer 7 due to the action of the coating layer 12, and the organic light emitting layer 7 It is possible to effectively prevent the occurrence of defects such as a decrease in luminance, a reduction in pixels due to enlargement of a non-light-emitting portion such as a dark frame, or a reduction in the lifetime of an organic EL display panel due to the deterioration of characteristics due to penetration. The material constituting the coating layer 12 is preferably a metal material different from the cathode electrode 8, a SiN material that does not allow water to permeate, or a Ca oxide that absorbs water, in addition to the metal material similar to the cathode electrode 8. Can be mentioned.

  Next, the manufacturing method of the organic EL display panel of the present invention will be described. FIG. 3 is an explanatory view showing a process of forming an organic light emitting layer, an electrode, and the like on the organic EL element substrate in manufacturing the organic EL display panel of the present invention. First, as shown in FIG. 3A, a transparent anode electrode 11 made of ITO is formed on one surface of a substrate organic EL element substrate 2 made of, for example, transparent glass.

  Then, an insulating layer 6 made of, for example, polyimide resin or the like is formed in a lattice shape on one surface 11a of the anode electrode 11, and the anode electrode 11 is partitioned for each rectangular region corresponding to a pixel. In order to form the insulating layer 6 in a lattice shape, for example, an insulating material may be formed on the entire surface 11a of the anode electrode 11 and then etched by using a photoresist or the like. Or what is necessary is just to form by the method of vapor-depositing using a lattice-like mask.

  Next, as necessary, as shown in FIG. 3B, a partition wall 9 rising from the upper surface of the insulating layer 6 is formed of, for example, a novolac resin or the like. The partition wall 9 may be formed in an inverted triangle shape whose width increases upward from the upper surface of the insulating layer 6. Such partition walls 9 may be formed, for example, by exposing and developing a positive photosensitive resin.

  Subsequently, as shown in FIG. 3C, the exposed portion of the anode electrode 11 and the end portion of the insulating layer 6 are provided between the adjacent insulating layers 6 to the end portion of the insulating layer 6. A covering organic light emitting layer 7 is formed. The organic light emitting layer 7 is formed by laminating the material for forming the organic light emitting layer 7 by vapor deposition using the mask 22 having the opening 21, so that only the portion of the opening 21 of the mask 22, that is, the anode electrode 11. An organic light emitting layer 7 is formed to cover the exposed portion and the end of the insulating layer 6. Note that the mask 22 may be vapor-deposited so as to be close to the top of the partition wall 9.

  As shown in FIG. 4A, a cathode electrode 8 is formed on the organic light emitting layer 7. In forming the cathode electrode 8, a material for forming the cathode electrode 8 may be laminated by vapor deposition using the same mask 22 used in the previous step.

  And as shown in FIG.4 (b), the membrane | film | coat layer 12 is laminated | stacked to the outer side rather than the edge part of the organic light emitting layer 7 or the cathode electrode 8. FIG. The coating layer 12 may be formed up to a position where the side end is in contact with the partition wall 9 while completely covering the organic light emitting layer 7 and the cathode electrode 8 to the end. The formation of the coating layer 12 may be performed by sputtering using the constituent material of the coating layer 12 as a target 13.

Preferred conditions for such sputtering include a low vacuum environment, for example, a pressure range of 200 to 1 × 10 ⁻² Pa, and a rare gas may be used as the target gas. In particular, when the shape of the partition wall 9 is an inverted triangle, in order to form the coating layer 12 up to the base portion of the partition wall 9 and completely cover the end portion of the organic light emitting layer 7, it is preferable to use Ar which is often used in normal sputtering. Also, it is preferable to use Kr, Xe or the like having a large mass number (heavy). By using a rare gas having a large mass number, the diffusibility of the target particles (coating material) during sputtering increases and diffuse reflection easily occurs, and it is difficult to stack by vapor deposition, such as the root portion of the inverted triangular partition wall 9. It becomes possible to laminate | stack the membrane | film | coat layer 12 which covers the organic light emitting layer 7 to an edge part.

  In this way, by forming the coating layer 12 on the organic light emitting layer 7 and the cathode electrode 8 formed by vapor deposition, it is possible to obtain a portion that is difficult to be laminated by vapor deposition, such as the base portion of the inverted triangular partition wall 9. The coating layer 12 is formed, and it becomes possible to completely prevent the penetration of moisture into the organic light emitting layer 7 without exposing the end face of the organic light emitting layer 7.

  In the embodiment of the present invention, the mask 22 having the opening 21 is used for forming the organic light emitting layer 7 and the cathode electrode 8. However, the present invention is not limited to this, and the adjacent organic light emitting layer 7 and the adjacent cathode electrode 8 are formed. A partition may be used for separation. The organic light emitting layer 7 and the cathode electrode 8 formed in the vapor deposition cannot extend to the base portion of the partition wall 9, but the coating layer 12 formed by the sputtering method of the present invention can cover the base portion of the partition wall 9, Regardless of the method of forming the organic light emitting layer 7 and the cathode electrode 8, the end face of the organic light emitting layer 7 is not exposed. That is, the penetration of moisture into the organic light emitting layer 7 can be completely prevented.

It is sectional drawing which shows an example of the organic electroluminescent display panel of this invention. It is the elements on larger scale of FIG. It is explanatory drawing which shows the manufacturing method of the organic electroluminescence display panel of this invention. It is explanatory drawing which shows the manufacturing method of the organic electroluminescence display panel of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Organic EL display panel, 2 ... Organic EL element substrate, 3 ... Sealing substrate, 6 ... Insulating layer, 7 ... Organic light emitting layer, 8 ... Cathode electrode, 9 ... Partition, 12 ... Film layer, 13 ... Target, 21 ... opening, 22 ... mask.

Claims (5)

  Forming an insulating layer dividing one surface of the anode electrode into a plurality of rectangular regions, forming a plurality of organic light emitting layers so as to cover one surface of the anode electrode and a part of the insulating layer, and the organic A step of forming a cathode electrode so as to cover at least a part of the light emitting layer, and a coating extending outside the periphery of the organic light emitting layer and the cathode electrode and covering the organic light emitting layer and the cathode electrode to the end A method of forming an organic EL display panel, wherein the step of forming the cathode electrode is performed by a vapor deposition method, and the step of forming the coating layer is performed by a sputtering method. 2. The method of manufacturing an organic EL display panel according to claim 1, wherein the sputtering method for forming the coating layer uses a rare gas as a sputtering gas in a pressure range of 200 to 1 × 10 ⁻² Pa. 3.   An insulating layer that divides one surface of the anode electrode into a plurality of rectangular regions, a plurality of organic light emitting layers that cover one surface of the anode electrode and a part of the insulating layer, and a plurality of layers that cover at least a part of the organic light emitting layer An organic EL display panel, comprising: a cathode electrode; and a coating layer extending to the outside of the organic light emitting layer and a periphery of the cathode electrode and covering the organic light emitting layer and the cathode electrode to the end.   4. The organic EL display panel according to claim 3, further comprising a partition wall rising from the insulating layer between the cathode electrodes adjacent to each other. The organic EL display panel according to claim 4, wherein an end portion of the coating layer is in contact with the partition wall.

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