JP2012216308A - Method for repairing sealing of organic el display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for repairing the sealing of an organic EL display device practical and adaptable to various adhesive materials.SOLUTION: A method for repairing the adhesion portion of an organic EL display device where the end of a cap sealing material 7 and a substrate 18 is bonded with an adhesive 16 so that the cap sealing material 7 covers an organic light-emitting layer formed on the substrate 18 in an airtight manner, comprises the steps of applying a laser-light absorbent binder 17 to the adhesion portion, generating thermal strain by applying laser light 19 to the binder, pulling the cap sealing material 7 apart from the substrate 1, and bonding the cap sealing material to the substrate anew.

Description

  The present invention relates to a repair method in a sealing portion of an organic EL display device.

  2. Description of the Related Art In recent years, organic EL display devices are widely used for displays and display elements such as in-vehicle components and mobile phones because they are excellent in visibility and flexibility and have various coloring properties.

  While these organic EL display devices have such excellent characteristics, they are generally known to be extremely weak against moisture. As an example, the organic EL display is caused by the moisture in the ambient atmosphere that is taken in when the outer peripheral portion of the organic EL element is sealed with a sealing material, or the moisture that permeates the defective portion of the sealing layer and enters the element. A non-light emitting area called a dark spot is generated in the apparatus, and there is a problem in life that light emission cannot be maintained.

  For this reason, in the conventional bottom emission type organic EL display device, a metal or glass sealing material (sealing cap) that blocks moisture is bonded to the back surface of the element with an adhesive to form a hollow structure. In general, a structure in which invading moisture is captured by a porous adsorbent sheet made of a hygroscopic adsorbent provided inside the sealing material and does not reach the light emitting site has been used.

  In the sealing process here, a sealing failure such as “mixing of air bubbles into the adhesion site” often occurs due to “positional deviation” between the element and the sealing material or “adhesive application failure”.

  In the sealing repair for the sealing failure in these organic EL display devices, it is difficult to remove the sealing portion by a relatively simple physical method such as grinding after the adhesive is cured. For example, when a semiconductor element sealing repair using a sealing cap similar to an organic EL display device using a sealing cap is given, in the repair that removes the sealing material and the adhesive on the so-called semiconductor element by grinding, The substrate surface is highly likely to be damaged, requiring many steps and careful work.

  In addition, about the thing of an epoxy-type resin in the conventional adhesive agent, the method of immersing in xylene for about 6 hours and making it melt | dissolve and separating a sealing material (sealing cap) is also possible. However, the adhesive is not completely dissolved by this method, and it is practical due to the problem that a large peeling shear force is required for removing the sealing material, or the problem that a problem occurs when the substrate surface is immersed in a solvent. Not.

Japanese Patent Laid-Open No. 10-67916 JP-A-10-137660

Until now, many of the organic EL display devices that have completed the sealing process have been detected to have a sealing failure, and since there was no practical repair method, many of them were discarded despite being originally expensive. This has contributed to yield reduction and cost increase. In addition, since the adhesive is melted or dissolved using heat or a solvent even when repair is performed by the conventional technique, there is a problem that the usable adhesive is limited and a sufficient sealing effect cannot be obtained.
Accordingly, an object of the present invention is to provide a sealing repair method for an organic EL display device that can handle practical and various adhesive materials.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that the end of the cap-type sealing material and the substrate are hermetically covered with the cap-type sealing material so as to hermetically cover the organic light emitting layer formed on the substrate. A method for repairing an adhesive portion of an organic EL display device that is bonded and fixed via an adhesive, wherein the repair method includes a step of applying a laser light absorbing binder to the adhesive portion, and irradiating the binder with laser. An organic EL display device comprising: a step of generating thermal strain between the adhesive and the substrate, a step of separating the cap-type sealing material from the substrate, and a step of bonding the cap-type sealing material to the substrate again. This is a repair method.

  The invention according to claim 2 is characterized in that the binder is selected from carbon paste, silver paste, chromium paste, gold paste, nickel paste, palladium paste, or a mixed paste thereof. Item 14. A method for repairing an organic EL display device according to Item 1.

  The invention according to claim 3 is the method for repairing an organic EL display device according to claim 1, wherein the cap-type sealing material is made of glass.

  The invention according to claim 4 is the organic EL display device repair method according to claim 1, wherein the laser irradiation is performed in an inert gas environment.

The present invention irradiates a sealing material of an organic EL element that has caused a sealing failure and a binder applied to a bonding portion of a substrate by irradiating a laser beam to generate thermal distortion in the bonding portion, thereby removing the sealing material from the element. It is easily peelable from the substrate and does not damage the light emitting portion.
Therefore, it is possible to return the organic EL element to a state where it can be sealed again before sealing, and an improvement in yield and a reduction in cost can be expected.

(A) Schematic diagram of organic EL display device, (b) Schematic diagram before film formation of organic light emitting medium layer of organic EL display device, (c) Schematic diagram after film formation of organic light emitting medium layer of organic EL display device It is. It is a schematic diagram of the printing machine for film-forming of the organic light emitting medium layer of an organic electroluminescence display. It is a schematic diagram in repair of the sealing part of an organic electroluminescence display. It is the schematic diagram which expanded the repair site | part. 10 is a schematic diagram of Comparative Example 3. FIG.

  FIG. 1 shows a cross-sectional view of a typical organic EL display device to which the present invention can be applied.

  The present invention will be described below with reference to the drawings. The present invention can be applied to both passive matrix type and active matrix type organic EL display devices.

  As shown in FIG. 1A, the organic EL element of the present invention has a first electrode 2 on a glass substrate 1. In the case of the passive matrix system, the first electrode 2 has a stripe pattern. In the case of the active matrix method, the first electrode 2 has a pattern for each pixel.

Moreover, the figure (b) shows the state before apply | coating the positive hole transport layer 4 and the organic light emitting layer 5 on a 1st electrode, and the figure (c) applies the positive hole transport layer 4 and the organic light emitting layer 5 to it. It is a figure which shows the state after having performed.

  Further, the second electrode 6 is disposed on the organic light emitting layer 5. In the case of the passive matrix system, the second electrode 6 is provided in a stripe shape so as to be orthogonal to the first electrode 2 having a stripe shape. In the case of the active matrix method, the second electrode 6 is a solid electrode formed on the entire surface of the organic light emitting layer.

  Next, a method for manufacturing the organic EL display device according to the present invention will be described.

  As the substrate, any substrate having an insulating property can be used. However, in the case of a bottom emission type organic EL display device in which light is emitted from the substrate side, it is necessary to use a transparent substrate.

  For example, a glass substrate or a quartz substrate can be used. Further, it may be a plastic film or sheet such as polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate. Metal oxide thin film, metal fluoride thin film, metal nitride thin film, metal oxynitride thin film, or polymer resin film for the purpose of preventing moisture from entering the organic light emitting medium layer in these plastic films and sheets You may utilize what laminated | stacked these as a board | substrate.

  In addition, it is more preferable to reduce the moisture adsorbed on the inside or the surface of the substrate as much as possible by performing a heat treatment on these substrates in advance. Further, in order to improve the adhesion depending on the material to be laminated on the substrate, it is preferable to use after performing surface treatment such as ultrasonic cleaning treatment, corona discharge treatment, plasma treatment, UV ozone treatment.

  Further, a thin film transistor (TFT) can be formed on these to form a substrate for an active matrix organic EL display device. A known thin film transistor can be used as the thin film transistor. Specifically, a thin film transistor mainly including an active layer in which a source / drain region and a channel region are formed, a gate insulating film, and a gate electrode can be given. The structure of the thin film transistor is not particularly limited, and examples thereof include a staggered type, an inverted staggered type, a top gate type, and a coplanar type.

  The active layer is not particularly limited, and examples thereof include inorganic semiconductor materials such as amorphous silicon, polycrystalline silicon, microcrystalline silicon, cadmium selenide, thiophene oligomers, poly (p-ferylene vinylene), and the like. It can be formed of an organic semiconductor material.

These active layers are formed by, for example, laminating amorphous silicon by plasma CVD, ion doping, forming amorphous silicon by LPCVD using SiH ₄ gas, and crystallizing amorphous silicon by solid phase growth. After obtaining silicon, ion doping by ion implantation, LPCVD using Si ₂ H ₆ gas, and amorphous silicon by PECVD using SiH ₄ gas, and excimer laser or other laser After annealing and crystallizing amorphous silicon to obtain polysilicon, polysilicon is laminated by ion doping (low temperature process), low pressure CVD or LPCVD, and thermally oxidized at 1000 ° C. or higher. Gate insulation film Formed, the gate electrode of the n ⁺ polysilicon is formed thereon, then, a method of ion doping (high temperature process), and the like by an ion implantation method.

As the gate insulating film, typically, it can be used that is used as a gate insulating film, for example, PECVD method, SiO formed by the LPCVD method or the like _2; SiO obtained polysilicon film was thermally oxidized ₂ Etc. can be used.

  As a gate electrode, what is normally used as a gate electrode can be used, for example, metals, such as aluminum and copper, refractory metals, such as titanium, tantalum, and tungsten, polysilicon, silicide of a refractory metal, Polycide etc. are mentioned.

  The thin film transistor may have a single gate structure, a double gate structure, or a multi-gate structure having three or more gate electrodes. Moreover, you may have a LDD structure and an offset structure. Further, two or more thin film transistors may be arranged in one pixel. The organic EL display device of this case needs to be connected so that the thin film transistor functions as a switching element of the organic EL display device, and the drain electrode of the transistor and the first electrode 2 of the organic EL display device are electrically connected. Yes. The thin film transistor, the drain electrode, and the first electrode 2 of the organic EL display device are connected through a connection wiring formed in a contact hole that penetrates the planarization film.

  A first electrode 2 is provided on the substrate. When the first electrode 2 is used as an anode, the material is a metal such as ITO (indium tin composite oxide), IZO (indium zinc composite oxide), tin oxide, zinc oxide, indium oxide, zinc aluminum composite oxide, etc. A single layer or laminated layer of metal materials such as composite oxide, gold, platinum, and chromium can be used. The first electrode 2 can be formed by a dry film forming method such as a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, or a sputtering method depending on the material.

  In addition, ITO is preferably used because of its low resistance, solvent resistance, and high transparency when the bottom mission method is adopted. ITO is formed on the glass substrate 1 by a sputtering method, and is patterned by the photolithography method to form the first electrode 2.

After the first electrode 2 is formed, the pixel partition 3 is formed so as to cover the edge of the first electrode. The pixel partition 3 needs to have insulating properties, and a photosensitive material or the like can be used. The photosensitive material may be a positive type or a negative type, a photo-curing resin of a photo radical polymerization system, a photo cationic polymerization system, or a copolymer containing an acrylonitrile component, polyvinyl phenol, polyvinyl alcohol. , Novolac resin, polyimide resin, cyanoethyl pullulan, and the like can be used. Further, as a partition wall forming _material, it is also possible to use SiO 2, TiO ₂ or the like.

When the partition wall forming material is a photosensitive material, the entire surface of the forming material solution is coated by a slit coating method or a spin coating method, and then patterning is performed by a photolithography method such as exposure and development. In the case of the spin coating method, the height of the partition wall can be controlled by conditions such as the number of rotations when spin coating, but there is a limit height in one coating, and if it is higher than that, multiple spin coatings are performed. Use an iterative approach. Further, when the partition wall forming material is SiO ₂ or TiO ₂ , it can be formed by a dry film forming method such as a sputtering method or a CVD method. The patterning of the partition walls can be performed by a mask or a photolithography method.

  Next, an organic light emitting medium layer is formed. The organic light-emitting medium layer may be composed of the organic light-emitting layer 5 alone, or assists light emission such as the hole transport layer 4 and the organic light-emitting layer 5, other hole injection layers, electron transport layers, and electron injection layers. It is good also as a laminated structure with the light emission auxiliary layer. The hole transport layer, hole injection layer, electron transport layer, and electron injection layer are appropriately selected as necessary.

  The organic light emitting layer 5 is a layer that emits light when an electric current is applied. Examples of the organic light-emitting material formed by the organic light-emitting layer 5 include 9,10-diarylanthracene derivatives, pyrene, coronene, perylene, rubrene, 1,1,4,4-tetraphenylbutadiene, tris (8-quinolato) aluminum complex, Tris (4-methyl-8-quinolate) aluminum complex, bis (8-quinolate) zinc complex, tris (4-methyl-5-trifluoromethyl-8-quinolate) aluminum complex, tris (4-methyl-5-cyano) -8-quinolate) aluminum complex, bis (2-methyl-5-trifluoromethyl-8-quinolinolate) [4- (4-cyanophenyl) phenolate] aluminum complex, bis (2-methyl-5-cyano-8- Quinolinolato) [4- (4-cyanophenyl) phenolate] aluminum complex , Tris (8-quinolinolato) scandium complex, bis [8- (paratosyl) aminoquinoline] zinc complex and cadmium complex, 1,2,3,4-tetraphenylcyclopentadiene, 2,5-diheptyloxy-para-phenylene A low molecular weight light emitting material such as vinylene can be used.

  Also, coumarin phosphors, perylene phosphors, pyran phosphors, anthrone phosphors, polyphyrin phosphors, quinacridone phosphors, N, N′-dialkyl-substituted quinacridone phosphors, naphthalimide phosphors, A material obtained by dispersing a low molecular weight light emitting material such as an N, N′-diaryl-substituted pyrrolopyrrole-based fluorescent pair or a phosphorescent light emitter such as an Ir complex in a polymer can be used. As the polymer, polystyrene, polymethyl methacrylate, polyvinyl carbazole and the like can be used.

  Also, poly (2-decyloxy-1,4-phenylene) (DO-PPP), poly [2,5-bis- [2- (N, N, N-triethylammonium) ethoxy] -1,4-phenyl- Alt-1,4-phenyllene] dibromide (PPP-NEt3) poly [2- (2′-ethylhexyloxy) -5-methoxy-1,4-phenylenevinylene] (MEH-PPV), poly [5-methoxy -(2-propanoxysulfonide) -1,4-phenylenevinylene] (MPS-PPV), poly [2,5-bis- (hexyloxy) -1,4-phenylene- (1-cyanovinylene)] ( CN-PPV) and poly (9,9-dioctylfluorene) (PDAF) may be used. Examples thereof include polymer precursors such as PPV precursor, PNV precursor, and PPP precursor. Further, a material obtained by dispersing or copolymerizing the low-molecular light-emitting material in these polymer materials, or other existing light-emitting materials can also be used.

  Examples of the material for the hole transport layer 4 include metal phthalocyanines such as copper phthalocyanine and tetra (t-butyl) copper phthalocyanine, and metal-free phthalocyanines, quinacridone compounds, 1,1-bis (4-di-p-tolylaminophenyl). ) Cyclohexane, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine, N, N′-di (1-naphthyl) -N , N′-diphenyl-1,1′-biphenyl-4,4′-diamine and other aromatic amine-based low molecular hole injection and transport materials, polyaniline, polythiophene, polyvinylcarbazole, poly (3,4-ethylenedioxy) Polymeric hole transport materials such as a mixture of thiophene and polystyrene sulfonic acid, polythiophene oligomer materials, and other existing hole transport materials It can be selected from among.

  As a material for the electron transport layer, 2- (4-bifinylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (1-naphthyl)- 1,3,4-oxadiazole, oxadiazole derivatives, bis (10-hydroxybenzo [h] quinolinolato) beryllium complexes, triazole compounds, and the like can be used.

Solvents that dissolve or disperse the organic light emitting material include toluene, xylene, acetone, hexane, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, 2-methyl- (t-butyl) Benzene, 1,2,3,4-tetramethylbenzene, pentylbenzene, 1,3,5-triethylbenzene, cyclohexylbenzene, 1,3,5-tri-isopropylbenzene and the like can be used alone or in combination. . Moreover, surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. may be added to organic luminescent ink as needed.

  Solvents that dissolve or disperse the hole transport material and electron transport material include, for example, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, water, etc. Alternatively, a mixed solvent thereof can be used. In particular, water or alcohols are suitable when forming a hole transport material into an ink.

  The organic light emitting medium layer is formed by a wet film forming method. In the case where the organic light emitting medium layer has a laminated structure, it is not necessary to form all of the layers by a wet film formation method. As the wet film forming method, spin coating method, die coating method, dip coating method, discharge coating method, pre-coating method, roll coating method, bar coating method and the like, relief printing method, inkjet printing method, offset printing method, Examples of the printing method include a gravure printing method. In particular, when the organic light emitting layer 5 is formed, it can be selectively applied to the pixel portion by using, for example, a printing method. For this reason, it is also possible to manufacture an organic EL element capable of color display by printing a light emitting layer that emits light in different colors on each pixel.

  In particular, the organic light emitting layer 5 is preferably formed by a relief printing method. The relief printing method is different from the ink jet method, and the ink is transferred so that the plate and the substrate are in direct contact. In the present invention, the letterpress used in the letterpress printing method is preferably a water development type resin letterpress. Examples of the water-developable photosensitive resin constituting the resin plate in the present invention include a type having a hydrophilic polymer and a monomer containing an unsaturated bond, a so-called crosslinkable monomer and a photopolymerization initiator as constituent elements. In this type, polyamide, polyvinyl alcohol, cellulose derivatives and the like are used as hydrophilic polymers. Examples of the crosslinkable monomer include methacrylates having a vinyl bond, and examples of the photopolymerization initiator include aromatic carbonyl compounds. Among these, a polyamide-based water-developable photosensitive resin is preferable from the viewpoint of printability.

  The printing apparatus used for forming the organic light emitting layer 5 can be any letterpress printing apparatus that prints on a flat plate, but the following printing apparatus is desirable. FIG. 2 shows a schematic diagram of the relief printing apparatus of the present invention. The manufacturing apparatus includes a plate cylinder 11 to which an ink tank 8, an ink chamber 9, an anilox roll 10, and a resin relief plate 12 are attached. The ink tank 8 contains an organic light-emitting ink diluted with a solvent, and the organic light-emitting ink is fed into the ink chamber 9 from the ink tank 8. The anilox roll 10 rotates in contact with the ink supply unit of the ink chamber 9 and the plate cylinder 11.

  As the anilox roll 10 rotates, the organic light-emitting ink supplied from the ink chamber 9 is uniformly held on the surface of the anilox roll 10 and then has a uniform film thickness on the convex portions of the resin relief plate 12 attached to the plate cylinder 11. It will transfer at. Further, the substrate to be printed 13 is fixed on a slidable substrate fixing table, and is moved to the printing start position while adjusting the position by the position adjustment mechanism of the plate pattern and the substrate pattern, and the plate cylinder 11 is rotated. At the same time, the convex portion of the resin relief plate 12 further moves while being in contact with the substrate, and the ink is transferred by patterning to a predetermined position of the printed substrate 13 on the stage 14.

Next, the second electrode 6 is formed. When the second electrode 6 is a cathode, a material having a high electron injection efficiency is used. Specifically, a single metal such as Mg, AL, or Yb is used, or a compound such as Li, oxidized Li, or LiF is sandwiched about 1 nm at the interface contacting the light emitting medium, and Al or Cu having high stability and conductivity is laminated. And use. Or, in order to achieve both electron injection efficiency and stability, one or more metals such as Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, etc., which have low work function, and stable Ag, Al An alloy system with a metal element such as Cu is used. Specifically, alloys such as MgAg, AlLi, and CuLi can be used. Further, in the case of a top emission type organic EL device, the cathode needs to have transparency, and for example, transparency can be achieved by a combination of these metals and a transparent conductive layer such as ITO.

  As a method for forming the second electrode 6, a dry film forming method such as a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, or a sputtering method can be used. The thickness is preferably about 10 nm to 1 μm. In the present invention, the first electrode can be a cathode and the second electrode can be an anode.

  This organic EL display device can emit light by passing an electric current through a portion where a light emitting material is sandwiched between both electrodes, but part of the organic light emitting medium layer and the electrode forming material is moisture in the atmosphere. Ordinarily, it is necessary to provide a sealing body for shielding from the outside.

  The sealing body is made of, for example, a glass sealing material 7 such as non-alkali glass or alkali glass on the substrate on which the first electrode 2, the organic light emitting medium layer including the organic light emitting layer 5, and the second electrode 6 are formed. It is formed by bonding the sealing material 7 and the organic EL display device in a glove box that removes moisture and oxygen and becomes an inert gas environment such as nitrogen and argon (FIG. 1).

  At this time, the bonding is performed on the bonding site via the adhesive 16 and the adhesive 16 is generally applied with a thickness of 5 to 10 μm by a dispenser. As the type of adhesive 16 used here, many epoxy resins are used. Specifically, epoxy resins such as prepolymers composed of bisphenol compounds and epichlorohydrin, acrylic acid esters, methacrylic acid esters, ethylene ethyl acrylate polymers, etc. A photo-curable adhesive resin and a thermosetting adhesive resin made of acrylic resin, silicone resin, etc., and a thermoplastic adhesive resin made of acid-modified products such as polyethylene and polypropylene can be used.

  Further, as a means for solidifying the adhesive 16 here, a mask is applied to a part other than the (adhesive 16) application site of the epoxy resin prepolymer, and ultraviolet light 365 nm is irradiated to the mask non-covering portion for 1 to 2 minutes. The sealing body can be completed by polymerizing.

  Here, the sealing procedure using the photocurable adhesive resin is described as an example, but the present invention is not limited to this.

  Hereinafter, the countermeasures against the sealing failure occurring here will be described.

  In the glove box which removes moisture and oxygen and becomes an inert gas environment such as nitrogen and argon, the interface (adhesive 16) between the substrate and the adhesive of the organic EL display device having a sealing failure and the sealing material 7 On the other hand, using a binder application dispenser 15 (see Patent Document 2), the binder 17 is applied with a thickness of about 10 μm so as not to adhere to the first electrode 2 (see FIG. 4).

  The binder 17 is a commercially available silver paste having a metal powder particle size of generally 100 μm or less, a corresponding content of 10 to 90 wt%, a sheet resistivity of 22 to 98 Ω / Sq, and a surface roughness of 3.6 to 11.4 μm. , Nickel paste, gold paste, palladium paste, chromium paste or carbon paste, or a blending agent composed of various mixing ratios of the pastes (for example, a blending agent composed of silver and carbon from Nagano Techtron Co., Ltd.) Select and use.

  At this time, if the binder 17 is applied with a thickness of about 10 μm or more, it may adhere to the first electrode 2 due to dripping. Therefore, it is necessary to pay attention to the applied thickness.

  A laser irradiation device 19 is used from the side of the substrate toward the coated binder 17 to irradiate the laser with an output of 50 to 100 μJ and a pulse width of 3 to 10 nsec.

  At this time, if the output value or pulse width is greater than the above value, the amount of heat generated is too large, so that heat may be transferred to the TFT circuit 18 and burnt. Since the amount of heat generated to dissociate the adhesive 16 cannot be obtained, attention must be paid to the output value and the pulse width.

  The laser irradiation device 19 used here is, for example, a MicroPoint laser generation device manufactured by Photonic Instruments Co., Ltd.

  However, although the above laser irradiation apparatus is taken as an example here, the present invention is not limited to this.

  The heat of the irradiated laser passes through the binder 17 and heats the sealing material 7 and the adhesive 16, and the sealing material 7 and the adhesive 16 are expanded by the heat, and distortion is generated due to the difference in expansion coefficient and dissociates. As a result, the adhesive 16 and the sealing material 7 can be peeled off from the TFT circuit substrate 18, and a reusable substrate is obtained (FIGS. 3 and 4).

  As a result, the epoxy resin used for the normal adhesive 16 cannot absorb the laser beam, but can absorb the heat derived from the laser beam and dissociate the sealing material 7 through the binder. Even when repairing is performed by the conventional technique (for example, Patent Document 1), the adhesive is melted or dissolved by heating or a solvent, but at this time, there is a certain restriction on the selection of the material of the epoxy adhesive. It was. However, in this example, the material of epoxy resin, for example, Adeka Resin EP-4100, Adeka Resin EP-4530, Adeka Resin EP-4901, manufactured by Asahi Denka Kogyo Co., Ltd., Epicron 840, Epicron 857, Epicron 830, Repair is possible without being limited to specific materials such as Epicoat 828, Epicoat 801, and Epicoat 807 manufactured by JER Corporation.

  In order for the thin film transistor to function as a switching element, a top emission backplane formed so as to be connected to the first electrode 2 through a contact hole formed in the planarization film is used, and the number of pixels is 240 × 320 dots. The number of pixels was 720 × 320 dots. Then, the first electrode 2 was formed by patterning ITO by a sputtering method so that the space between the sub-pixels was 40 μm in length and 100 μm in width at a pitch of 120 μm × 360 μm.

  Next, a positive photosensitive material TELR series (manufactured by Tokyo Ohka Co., Ltd.) was applied to the entire effective surface by a spin coating method. Then, exposure (10 sec) and development were performed to form a pixel partition wall 3 having a height of 0.5 μm as shown in FIG.

Next, a 0.1 μm-thick poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid mixture (hereinafter referred to as PEDOT / PSS) is dispersed in water as the hole transport layer 4 on the first electrode 2. Then, a film was formed by a spin coating method. Thereafter, the hole transport ink in unnecessary portions around the effective pixels was removed by wiping with methanol.

  Next, polyphenylene vinylene derivatives, which are organic light emitting materials having emission colors of red 5 (R), green 5 (G), and blue 5 (B), are applied to a relief printing method using a water-developable photosensitive resin relief plate. The organic light emitting layer 5 was formed for each color. At this time, using an anilox roll of 150 lines / inch, the thickness of the organic light emitting layer 5 obtained was 80 nm for each color.

  Next, as the second electrode 6, Ba was deposited with a thickness of 5 nm by vacuum deposition, and Al was deposited thereon with a thickness of 20 nm. Then, without exposing to the atmosphere, a photocurable adhesive was applied to a dispenser with a thickness of 10 μm in a so-called inert gas environment under nitrogen at a dew point of −80 ° C. and an oxygen concentration of 1 ppm. Sealing was performed by irradiating the adhesion site with light for 1 minute to obtain an organic EL display device.

  As a repair method for the sealing displacement generated here, first, at the interface between the organic EL display device, the sealing glass 7 and the adhesive 16 in a glove box which removes moisture and oxygen and becomes an inert gas environment such as nitrogen and argon. On the other hand, a silver paste manufactured by Nagano Techtron Co., Ltd., having a powder particle size of 90 μm, a content rate of 80 wt%, a sheet resistivity of 74 Ω / Sq, and a surface roughness of 4.1 μm as a binder 17 using a binder coating dispenser 15 is 10 μm. After coating with a thickness of 1, a laser beam is emitted at an output of 100 μJ and a pulse width of 3 nsec to generate thermal strain toward this part using a MicroPointo laser generator manufactured by Photonic Instruments Co., Ltd. Thermal strain is generated in the stop glass 7 and peeled off from the TFT circuit 18 (FIG. 4).

  The organic EL display device from which the sealing glass 7 has been peeled off does not cause any problems in the organic light emitting layer 5 and the TFT circuit 18 and maintains the same state as before sealing, and is sealed again and completed as a repair product. As a result of inspecting the characteristics, results comparable to good products were obtained (Table 1).

(Comparative Example 1)
The poorly sealed organic EL display device generated through the same steps as in Example 1 was heated on a hot plate at 300 ° C. to try to melt the adhesive 16. As a result, the sealing glass 7 was successfully peeled, but a part of the organic layer was thermally deformed (film unevenness) due to heating, and the characteristics of the organic EL display device after resealing were reduced (Table). 1).

(Comparative Example 2)
The poorly sealed organic EL display device generated through the same steps as in Example 1 was immersed in xylene for 6 hours to try to dissolve the adhesive 16. As a result, the sealing glass 7 was successfully peeled off, but when immersed, the organic layer was partially swollen (film unevenness) due to the penetration of xylene into the organic layer, and the organic EL display device after resealing (Table 1).

(Comparative Example 3)
An abrasive was used for the sealing portion of the poorly sealed organic EL display device generated through the same steps as in Example 1, and an abrasive was used to polish the interface between the sealing glass 7 and the adhesive 16. . As a result, the sealing glass 7 was successfully peeled off, but a partial wiring break 21 of the TFT circuit 18 due to polishing was confirmed, and the state could not be restored to the state of the organic EL display device before sealing (FIG. 5 and Table 1). ).

According to the present invention, an organic EL display device that has caused a defect in a sealing portion that should be discarded so far can be regenerated as an organic EL display device precursor that can be sealed again by peeling off the sealing material, and the yield Can be improved.

DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... 1st electrode 3 ... Pixel partition 4 ... Hole transport layer 5 ... Organic light emitting layer 6 ... 2nd electrode layer 7 ... Sealing material 8 ... Ink tank 9 ... Ink chamber 10 ... Anilox roll 11 ... Plate cylinder 12 ... Resin letter plate 13 ... Print substrate 14 ... Stage 15 ... Binder application dispenser 16 ... ..Adhesive 17 ... Binder 18 ... TFT circuit board 19 ... Laser irradiation device 20 ... Panel file brush 21 ... Wiring break

Claims (4)

  The organic EL display device is configured such that the end of the cap type sealing material and the substrate are bonded and fixed with an adhesive so that the organic light emitting layer formed on the substrate is hermetically covered with the cap type sealing material. A method for repairing an adhesive portion, which includes a step of applying a laser light absorbing binder to the adhesive portion, a step of generating thermal strain between the adhesive and the substrate by irradiating the binder with laser, and a cap type A method for repairing an organic EL display device, comprising: a step of separating the sealing material from the substrate; and a step of newly bonding the cap-type sealing material to the substrate.   2. The organic EL display according to claim 1, wherein the binder is selected from a carbon paste, a silver paste, a chromium paste, a gold paste, a nickel paste, and a palladium paste, or a mixed paste thereof. Device repair method.   The method for repairing an organic EL display device according to claim 1, wherein the cap-type sealing material is made of glass.   The method of repairing an organic EL display device according to claim 1, wherein the laser irradiation is performed in an inert gas environment.

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