JP2007095521A - Manufacturing method of organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming an organic light-emitting layer and a charge transport layer precisely with less time and labor as well as suppressing crosstalk when manufacturing an organic EL element. <P>SOLUTION: This is the manufacturing method of the organic electroluminescent element which is at least equipped with the base body, with a first electrode installed on the base body, with a barrier rib formed corresponding to the first electrode, with the charge transport layer and the organic light-emitting layer formed in a region sectioned by the barrier rib, and with a second electrode. The barrier rib has a lattice shape formed from a first barrier rib in parallel with a first straight line and a second barrier rib in parallel with a second straight line, and the height of the first barrier rib is larger than that of the second barrier rib. This manufacturing method is equipped with a process of forming the charge transport layer by a printing method using a printing plate having a scanning part corresponding to the second barrier rib, and a process of forming the organic light-emitting layer the printing method using the printing plate having the scanning part corresponding to the first barrier rib. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an organic electroluminescence element (hereinafter, referred to as an organic EL element) that is expected to be widely used as a display such as an information display terminal or a surface-emitting light source.

In an organic EL element, a light emitting layer made of an organic light emitting material is formed between two opposing electrodes, and light is emitted by passing a current through the light emitting layer. Is important, and a thin film of about 100 nm is required. Further, in order to make this a display, it is necessary to pattern it with high definition.
The organic light emitting material for forming the light emitting layer includes a low molecular material and a high molecular material. Generally, a low molecular material is formed into a thin film by a resistance heating vapor deposition method or the like, and is patterned using a fine pattern mask at this time. This method has a problem that the larger the substrate is, the more difficult patterning accuracy is.

  Therefore, recently, a method of using a polymer material as an organic light emitting material, dispersing or dissolving the organic light emitting material in a solvent to form a coating solution, and forming a thin film by a wet coating method has been tried. As the wet coating method for forming a thin film, there are a spin coating method, a bar coating method, a protruding coating method, a dip coating method, and the like. For high-definition patterning and colorization, for example, red, green and blue 3 In order to separate the colors, it is difficult to use these wet coating methods, and it is considered most effective to form a thin film by a printing method that is good at coating and patterning.

  Further, among various printing methods, in organic EL elements and displays using glass as a substrate, a method using a hard plate such as a metal printing plate such as a gravure printing method is unsuitable, and an elastic rubber blanket. An offset printing method using, and a relief printing method using an elastic rubber plate or resin plate are also suitable. Actually, as an attempt by these printing methods, a method by offset printing (see Patent Document 1), a method by letterpress printing (see Patent Document 2), and the like have been proposed.

  However, the printing method has a problem that printing cannot be performed unless the correspondence between the patterned printing plate and the substrate to be printed is one-to-one, and alignment is also necessary. In particular, when grid-like partition walls are formed corresponding to pixels on the substrate to be printed, vertical and horizontal alignment must be performed, so printing takes time, and the position is shifted due to expansion and contraction of the plate. There was a problem.

In addition, a charge transport layer such as a hole transport layer that does not require separate coating is generally formed by coating a whole surface by spin coating, protruding coating, dip coating, etc. using a polymer coating type material. there were. However, it has been found that when the charge transport layer is formed on the entire surface, crosstalk that seems to be caused by leakage of current from the pixel electrode becomes a problem.
JP 2001-93668 A JP 2001-155858 A

  It is an object of the present invention to form an organic light emitting layer and a charge transport layer with high accuracy and less crosstalk and to suppress crosstalk when manufacturing an organic EL element.

  A first invention made to solve this problem includes at least a base, a first electrode provided on the base, a partition formed corresponding to the first electrode, and a region partitioned by the partition A method for manufacturing an organic electroluminescent device comprising a charge transport layer and an organic light emitting layer formed therein, and a second electrode, wherein the barrier ribs are parallel to a first barrier rib and a second straight line. The grid is formed from the second partition, the first partition is higher than the second partition, and the charge transport layer is formed by a printing method using a printing plate having an image line corresponding to the second partition. A method for producing an organic electroluminescent element, comprising: a step; and a step of forming an organic light emitting layer by a printing method using a printing plate having an image line corresponding to a first partition.

The second invention is the method of manufacturing an organic electroluminescence element according to claim 1, wherein the height of the first partition is larger than 1 μm.
According to a third aspect of the invention, in the step of forming the charge transport layer and the organic light emitting layer, the printing method is a relief printing method using a relief plate as a printing plate. The organic electroluminescence device according to claim 1 or 2, It is a manufacturing method.

According to the present invention, it is possible to perform printing with high accuracy only by alignment in one direction, and it is possible to manufacture a printed body with high yield.
According to the present invention, since the charge transport layer is printed over the high first barrier rib, the charge transport material hardly remains on the barrier rib, and an anode short-circuit between adjacent pixels can be prevented. Therefore, crosstalk can be prevented. In the case of the passive matrix driving type, the driving voltage can be kept low.

  Since the organic light emitting material is printed over the lower second partition wall, the distance between the printing plate and the substrate to be printed is reduced, and the ink can be transferred reliably. Further, when an electrode or a sealing material is laminated on the upper surface of the organic light emitting layer, problems such as disconnection on the partition walls can be prevented. In addition, since the first color is separated from the other colors by a high first partition at the time of multi-coloring, color mixing can be prevented.

  The organic EL device 10 of the present invention includes a substrate 11, a partition wall 13 provided on the substrate, and an organic light emitting medium layer 14 formed in a region partitioned by the partition wall (FIG. 1A). The partition walls have a lattice shape formed by a first partition wall parallel to the first straight line and a second partition wall parallel to the second straight line. A first electrode 12 is provided below the organic light emitting medium layer, and a second electrode 15 is provided above the organic light emitting medium layer, and has a structure sandwiching the organic light emitting medium layer. A sealing body 16 for protecting the organic light emitting medium layer from the external environment is provided on the second electrode. The organic light-emitting medium layer includes a charge transport layer 14a and an organic light-emitting layer 14b. The charge transport layer is formed on a second partition, and the organic light-emitting layer is printed using a printing plate having an image line corresponding to the first partition. Is formed.

<Board>
The substrate 11 serves as a support for the organic EL element of the present invention (FIG. 1A). Any substrate can be used as long as it has insulating properties and excellent dimensional stability. For example, plastic films and sheets such as glass, quartz, polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, etc., or oxidation to these plastic films and sheets Metal oxides such as silicon and aluminum oxide, metal fluorides such as aluminum fluoride and magnesium fluoride, metal nitrides such as silicon nitride and aluminum nitride, metal oxynitrides such as silicon oxynitride, acrylic resins and epoxy resins Translucent base material with a single layer or laminated polymer resin film such as silicone resin or polyester resin, metal foil such as aluminum or stainless steel, sheet, plate, aluminum on the plastic film or sheet It can be used um, copper, nickel, stainless steel and metal film non-translucent substrate as a laminate of such. What is necessary is just to select the translucency of a base material according to which surface light extraction is performed from. The substrate made of these materials may have been subjected to moisture-proofing treatment or hydrophobic treatment by forming an inorganic film or applying a fluororesin in order to avoid moisture intrusion into the organic EL element. preferable. In particular, in order to avoid intrusion of moisture into the organic light emitting medium, it is preferable to reduce the moisture content and gas permeability coefficient in the substrate.

Further, as these substrates, a driving substrate on which a thin film transistor (TFT) is formed may be used as needed (FIG. 1B).
When the organic EL element of the present invention is an active drive type, a planarizing layer 117 is formed on the TFT 120, and a lower electrode (first electrode 12) of the organic EL element is disposed on the planarizing layer 117. It is preferable that the TFT and the lower electrode are electrically connected via a contact hole 118 provided in the planarization layer 117. By comprising in this way, the outstanding electrical insulation can be obtained between TFT and an organic EL element.

The TFT 120 and the organic EL element formed above the TFT 120 are supported by a support 111. The support is preferably excellent in mechanical strength and dimensional stability. Specifically, the materials described above as the substrate can be used.
As the thin film transistor 120 provided over the support, a known thin film transistor can be used. 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 112 is not particularly limited, and examples thereof include amorphous semiconductor materials such as amorphous silicon, polycrystalline silicon, microcrystalline silicon, cadmium selenide, thiophene oligomers, poly (p-ferylene vinylene), and the like. The organic semiconductor material can be used. 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 silicon is obtained, ion doping is performed by ion implantation; amorphous silicon is formed by LPCVD using Si ₂ H ₆ gas, or PECVD using SiH ₄ gas, and a laser such as an excimer laser is used. After annealing and crystallizing amorphous silicon to obtain polysilicon, a method of ion doping by ion doping (low temperature process); polysilicon is deposited by low pressure CVD or LPCVD, and thermally oxidized at 1000 ° C. or higher Gate break Film is formed, an n + polysilicon gate electrode 114 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 113, a film normally used as a gate insulating film can be used. For example, SiO ₂ formed by PECVD, LPCVD, etc .; SiO obtained by thermally oxidizing a polysilicon film ₂ etc. can be used.
As the gate electrode 114, a material usually used as a gate electrode can be used. For example, a metal such as aluminum or copper; a refractory metal such as titanium, tantalum or tungsten; polysilicon; a silicide of a refractory metal Polycide; and the like.
The thin film transistor 120 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.

When the organic EL element of the present invention is an active drive type, the thin film transistor needs to be connected so as to function as a switching element of the organic EL element, and the drain electrode 116 of the transistor and the pixel electrode (first electrode of the organic EL element) The electrode 12) is electrically connected. Further, it is generally necessary to use a metal that reflects light as a pixel electrode for taking a top emission structure.
The thin film transistor 120, the drain electrode 116, and the pixel electrode 12 of the organic EL element are connected through a connection wiring formed in a contact hole 118 that penetrates the planarization film 117.

Regarding the material of the planarizing film 117, inorganic materials such as SiO ₂ , spin-on glass, SiN (Si ₃ N ₄ ), TaO (Ta ₂ O ₅ ), organic materials such as polyimide resin, acrylic resin, photoresist material, and black matrix material are used. Materials and the like can be used. Spin coating, CVD, vapor deposition, etc. can be selected according to these materials. If necessary, a contact hole 118 is formed by dry etching, wet etching, or the like at a position corresponding to the lower layer thin film transistor 120 by photolithography using a photosensitive resin as the planarizing layer, or once the planarizing layer is formed on the entire surface. Form. The contact hole is then filled with a conductive material to establish conduction with the pixel electrode formed in the upper layer of the planarization layer. The thickness of the planarizing layer is not limited as long as it can cover the lower TFT, capacitor, wiring, etc., and the thickness may be several μm, for example, about 3 μm. FIG. 1B shows a cross-sectional view of an example of a substrate that can be used as the substrate 11 for the active matrix driving type organic EL element.

<First electrode>
The first electrode 12 is formed on the substrate 11 and patterned as necessary (FIG. 1A). Usually, when the organic EL element is a passive drive type, it is formed in a stripe shape, and when it is an active drive type, it is formed independently for each pixel. In the present invention, the first electrode is partitioned by the first partition and the second partition, and becomes a pixel electrode corresponding to each pixel. As materials for the first electrode, metal composite oxides such as ITO (indium tin composite oxide), indium zinc composite oxide and zinc aluminum composite oxide, metal materials such as gold and platinum, these metal oxides, Either a single layer or a laminate of fine particle dispersion films in which fine particles of a metal material are dispersed in an epoxy resin or an acrylic resin can be used. When the first electrode is used as an anode, it is preferable to select a material having a high work function such as ITO. In the case of a so-called bottom emission structure in which light is extracted from below, it is necessary to select a light-transmitting material. If necessary, a metal material such as copper or aluminum may be provided as an auxiliary electrode in order to reduce the wiring resistance of the first electrode. Depending on the material, the first electrode can be formed by a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, a sputtering method, a dry film forming method, a gravure printing method, or a screen printing method. A wet film forming method such as a method can be used. As a patterning method for the first electrode, an existing patterning method such as a mask vapor deposition method, a photolithography method, a wet etching method, or a dry etching method can be used depending on the material and the film forming method. In the case of using a substrate on which a TFT is formed as a substrate, it is formed so that conduction can be achieved corresponding to a lower pixel.

<Partition wall>
The partition wall 13 of the present invention is formed so as to partition the light emitting region corresponding to the pixel. The end portion of the first electrode has large irregularities, and if it cannot be covered with the organic light emitting medium layer formed above, it may cause a short circuit. Therefore, the end portion of the first electrode is preferably formed so as to cover the end portion of the first electrode (FIG. (A), (b)). The partition wall is composed of first partition walls 24 and 33 parallel to the first straight line and second partition walls 23 and 32 parallel to the second straight line, and each has a lattice shape (FIGS. 2 and 3). The first straight line and the second straight line are fictitious straight lines determined for convenience corresponding to the movement directions of the printing plate and the substrate to be printed, and are usually orthogonal to each other.
In the present invention, the image line portion of the printing plate used for printing the charge transport layer corresponds to the second partition, and the image line portion of the printing plate used for printing the organic light-emitting layer extends to the first partition. Correspondingly formed and printed over the second partition. The second partition should be configured so as not to affect the printing more than the first partition. Specifically, the second partition may be lower than the first partition or not impart liquid repellency. it can.

  As in the conventional method, a lattice-shaped partition wall is formed by uniformly forming an inorganic film on a substrate, masking it with a resist, and performing dry etching, or laminating a photosensitive resin on the substrate and photolithography. The method of making a predetermined pattern by a method is mentioned. If necessary, a water repellent can be added, or plasma or UV can be irradiated to impart liquid repellency to the ink after formation. This method can be applied when the heights of the first partition and the second partition are the same.

As a method for forming a partition wall having a second partition wall lower than the first partition wall, for example, an inorganic film such as SiO _{2 is} laminated on the substrate by, for example, 0.5 μm by a CVD method, and then a dry etching method is used to deal with the light emitting region. Then, the openings are formed, the second partition walls and the lattice-shaped inorganic partition walls which are the lower portions of the first partition walls are formed, and then, for example, 0.8 μm of a photosensitive resin is laminated by a slit coating method, and then through an exposure / development process. There is a method in which a stripe-shaped first partition upper portion is formed above the first partition lower portion, and this is combined with the first partition lower portion to form a first partition. You may provide liquid repellency to the photosensitive resin.
Alternatively, the second partition wall and the lattice-shaped organic partition wall to be the lower part of the first partition wall may be formed by photolithography using a photosensitive resin, and the same process may be repeated again to form the upper part of the first partition wall.

When the second partition is lower than the first partition, the lower limit of the height of the first partition is higher than 1 μm, more preferably 3 μm or more, and most preferably 5 μm or more. The patterns can be separated well. In consideration of the cathode formed above and the sealing layer, the upper limit of the height of the partition wall is 15 μm or less, more preferably 10 μm or less. The height of the second partition is preferably in the range of 0.5 μm to 2 μm, and the width of the first partition and the second partition is in the range of about 3 μm to 50 μm. The same effect can be obtained by narrowing the width of the second partition relative to the first partition. However, if the width of the partition is too large, the opening is narrowed, so that the second partition is made forward tapered. For example, the width of the upper part of the partition wall can be narrowed without dropping the corner and rounding the first partition wall into the light emitting region.
As the shape of the partition wall, in addition to the linear shape shown in the drawing, the intersection of the first partition wall and the second partition wall can be rounded to the light emitting region side so that the ink can easily flow around the opening. Moreover, a part of 2nd partition can be made thin or low.

<Organic luminescent medium layer>
Next, the organic light emitting medium layer 14 is formed (FIG. 1A). The organic light emitting medium layer 14 in the present invention can be formed of a single layer film or a multilayer film containing a light emitting substance. Examples of the configuration in the case of forming a multilayer film include a hole transport layer, an electron transporting light emitting layer or a hole transporting light emitting layer, a two-layer structure comprising an electron transport layer, a hole transport layer, a light emitting layer, and an electron transport layer. By further separating the hole (electron) injection function and the hole (electron) transport function as necessary, or by inserting a layer that blocks the transport of holes (electrons), if necessary, It is more preferable to form a multilayer. In addition, the organic light emitting layer in the present invention refers to a layer containing an organic light emitting material, and the charge transport layer refers to a layer formed to increase other light emission efficiency such as a hole transport layer.

  Examples of hole transport materials 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, Aromatic amine low molecular hole injection and transport materials such as N′-diphenyl-1,1′-biphenyl-4,4′-diamine, polyaniline, polythiophene, polyvinylcarbazole, poly (3,4-ethylenedioxythiophene) ) And polystyrene sulfonic acid and other polymer hole transport materials, polythiophene oligomer materials, and other existing hole transport materials It is possible to choose from.

  As organic light-emitting materials, 9,10-diarylanthracene derivatives, pyrene, coronene, perylene, rubrene, 1,1,4,4-tetraphenylbutadiene, tris (8-quinolinolato) aluminum complex, tris (4-methyl-8) -Quinolinolato) aluminum complex, bis (8-quinolinolato) zinc complex, tris (4-methyl-5-trifluoromethyl-8-quinolinolato) aluminum complex, tris (4-methyl-5-cyano-8-quinolinolato) aluminum complex Bis (2-methyl-5-trifluoromethyl-8-quinolinolato) [4- (4-cyanophenyl) phenolate] aluminum complex, bis (2-methyl-5-cyano-8-quinolinolato) [4- (4 -Cyanophenyl) phenolate] aluminum complex, Lis (8-quinolinolato) scandium complex, bis [8- (para-tosyl) aminoquinoline] zinc complex and cadmium complex, 1,2,3,4-tetraphenylcyclopentadiene, pentaphenylcyclopentadiene, poly-2,5 -Diheptyloxy-para-phenylene vinylene, coumarin phosphor, perylene phosphor, pyran phosphor, anthrone phosphor, porphyrin phosphor, quinacridone phosphor, N, N'-dialkyl-substituted quinacridone fluorescence , Naphthalimide-based phosphors, N, N′-diaryl-substituted pyrrolopyrrole-based phosphors, phosphorescent phosphors such as Ir complexes, and other low-molecular light-emitting materials, polyfluorene, polyparaphenylene vinylene, polythiophene, polyspiro High molecular materials such as, and low molecular weight materials Materials and dispersed or copolymerized, it is possible to use other existing polymer-low molecular luminescent material.

  Examples of the electron transport material include 2- (4-bifinylyl) -5- (4-tert-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. For the formation, vacuum deposition or the like can be used.

  The film thickness of the organic light emitting medium layer 14 is 1000 nm or less, preferably 50 to 150 nm, even when formed by a single layer or a stacked layer. In particular, the hole transport material of the organic EL element has a large effect of covering the surface protrusions of the substrate and the first electrode, and it is more preferable to form a film having a thickness of about 50 to 100 nm.

  As a method for forming the organic light emitting medium layer 14, depending on the material constituting each layer, a vacuum deposition method, a coating method such as spin coating, spray coating, flexo, gravure, micro gravure, intaglio offset, printing method or ink jet method is used. Etc. can be used. When the material constituting the organic light emitting medium layer is made into a solution, it is preferable to control the vapor pressure, the solid content ratio, the viscosity, and the like of the solvent according to the forming method. Solvents include water, xylene, anisole, cyclohexanone, mesitylene, tetralin, cyclohexylbenzene, methyl benzoate, ethyl benzoate, toluene, ethanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, isopropyl alcohol, ethyl acetate, butyl acetate, etc. These may be a single solvent or a mixed solvent. In order to improve coatability, it is more preferable to mix an appropriate amount of additives such as surfactants, antioxidants, viscosity modifiers and ultraviolet absorbers as necessary. As a method for drying the coating solution, the solvent may be removed to the extent that the light emission characteristics are not hindered, and heating, decompression, or heating / decompression may be performed.

  In the present invention, at least one of the charge transport layers constituting the organic light emitting medium layer 14 and the organic light emitting layer are formed by a printing method. When the charge transport layer is formed by the method of the present invention, current leakage can be prevented. Further, when the organic light emitting layer is formed by the method of the present invention, it is possible to preferably perform color coding corresponding to coloration. Further, if all the layers constituting the organic light emitting medium layer are formed by a printing method using a printing plate corresponding to any partition wall, the manufacturing process can be greatly simplified.

<Formation of charge transport layer and organic light emitting layer>
The charge transport layer and the organic light emitting layer (that is, part or all of the organic light emitting medium layer) included in the organic EL device of the present invention are formed by a printing method. Examples of the printing method that can be used in the present invention include a relief printing method, a gravure printing method, and a planographic (offset) printing method. A substrate as a substrate to be printed on which the organic light emitting medium layer is formed often uses glass or a plastic film. Therefore, since it is vulnerable to local pressure and has a high risk of breakage, a type using a resin or rubber plate is preferably selected from offset printing methods and letterpress printing methods in which the surface that contacts the substrate to be printed is formed of a resin such as rubber. can do. In the case of using the offset printing method, the relief reversal offset method is preferable because the film thickness can be formed uniformly.

<Letterpress printing method>
The relief printing method, which is a printing method that can be preferably used in the present invention, will be described in detail.
As the relief plate that can be used for forming part or all of the organic light emitting medium layer, it is preferable to use a water development type resin relief plate. Examples of the water-developable photosensitive resin constituting such a resin plate 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. Of these, a polyamide-based water-developable photosensitive resin is preferable from the viewpoint of printing suitability. The convex part (image area) of the printing plate has a height of several hundred μm and is elastic, and the partition of the substrate to be printed is at most several μm, so it can overcome the first partition and the second partition sufficiently. Can be printed.

  The printing machine used for forming part or all of the organic light emitting medium layer can be any relief printing machine that prints on a flat plate as a substrate to be printed, but a printing machine as shown below is desirable. FIG. 4 shows a schematic diagram of the printing press. The manufacturing apparatus has a plate cylinder 46 to which an ink tank 41, an ink chamber 42, an anilox roll 43, and a resin relief plate 45 are attached. The ink tank 41 contains organic luminescent medium ink diluted with a solvent, and the organic luminescent medium ink is fed into the ink chamber 42 from the ink tank 41. The anilox roll 43 rotates in contact with the ink supply part of the ink chamber 42 and the plate cylinder 46.

  As the anilox roll 43 rotates, the organic light emitting medium ink 44 supplied from the ink chamber is uniformly held on the anilox roll surface by a doctor blade (not shown), and then uniformly on the convex portions of the resin relief plate attached to the plate cylinder. Transition with film thickness. Further, the substrate 48 to be printed is fixed on a slidable substrate fixing stage (stage 47) and 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 The convex portion of the resin relief printing plate further moves in contact with the substrate in accordance with the rotation of the ink, and the ink is transferred by patterning to a predetermined position on the substrate.

<Letter offset printing method for letterpress>
The letterpress reverse offset method, which is another printing method that can be preferably used in the present invention, will be described in detail.
FIG. 5 schematically shows an example of a letterpress reverse offset printing apparatus that can be used to form part or all of the organic light emitting medium layer. The letterpress reverse offset printing apparatus includes a blanket that is a support for the laminated material, an ink supply mechanism (not shown) that supplies an ink-like laminated material to the blanket, and an unnecessary portion for removing unnecessary portions from the laminated material on the support. With a relief printing plate. In addition, a transfer target (printed substrate) is disposed on a stage below the transfer member, and is sent out as printing progresses.

The blanket is composed of a blanket cylinder 51 and a silicone blanket 52 wound around the blanket cylinder and constituting a surface.
An ink-like laminated material 53 is applied to an effective surface of a silicone blanket installed on the blanket cylinder from an ink supply means (not shown) and dried to form a coating film (FIG. 5A).

  Next, the blanket cylinder 51 is rotated, the convex printing plate 54 on which the negative pattern (non-image area) of the ink is formed and the silicone blanket 52 are pressure-bonded, and the stage on which the convex printing plate is fixed is moved according to the rotation of the blanket cylinder Let At this time, the laminated material 53b pressure-bonded to the convex portion 54a of the relief printing plate is removed from the blanket and transferred to the convex portion of the relief printing plate, and a pattern 53a of a desired lamination material is formed on the blanket (FIG. 5B). )).

  Next, the blanket cylinder 51 is rotated, the printed substrate 55 and the silicone blanket 52 are pressure-bonded, and the stage on which the printed substrate is fixed is moved in accordance with the rotation of the blanket cylinder. At this time, the patterned laminated material 53a on the silicone blanket is printed on the substrate to be printed (FIG. 5C).

<Second electrode>
Next, the second electrode 15 is formed (FIG. 1A). When the second electrode is a cathode, a substance having a high electron injection efficiency into the organic light emitting medium layer 14 and a low work function 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 by about 1 nm at the interface contacting the light emitting medium, and Al or Cu having high stability and conductivity is laminated. May be used. Alternatively, 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, and Yb having a low work function and stable Ag, Al An alloy system with a metal element such as Cu or Cu may be used. Specifically, alloys such as MgAg, AlLi, and CuLi can be used. In the case of a so-called top emission structure in which light is extracted from the second electrode side, it is preferable to select a light-transmitting material. In this case, after thinly providing Li and Ca having a low work function, a metal composite oxide such as ITO (indium tin composite oxide), indium zinc composite oxide, or zinc aluminum composite oxide may be laminated. The organic light emitting medium layer 4 may be laminated with a metal oxide such as ITO by doping a small amount of a metal such as Li or Ca having a low work function.

  As a method for forming the second electrode, 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 depending on the material. Although there is no restriction | limiting in particular in the thickness of a 2nd electrode, About 10 nm-1000 nm are desirable. Moreover, when utilizing a 2nd electrode as a translucent electrode layer, about 0.1-10 nm is desirable for the film thickness in the case of using metal materials, such as Ca and Li.

<Sealing body>
As an organic EL device, it is possible to emit light by sandwiching a light emitting material between electrodes and passing an electric current. However, since the organic light emitting material is easily deteriorated by moisture and oxygen in the atmosphere, it is usually cut off from the outside. A sealing body is provided.
The sealing body 16 can be formed, for example, by providing the resin layer 16b on the sealing material 16a (FIG. 1A).

The sealing material 16a needs to be a base material having low moisture and oxygen permeability. Examples of the material include ceramics such as alumina, silicon nitride, and boron nitride, glass such as alkali-free glass and alkali glass, metal foil such as quartz, aluminum, and stainless steel, and moisture-resistant film. Examples of moisture-resistant films include films formed by CVD of SiOx on both sides of plastic substrates, films with low permeability and water-absorbing films, or polymer films coated with a water-absorbing agent. The water vapor transmission rate is preferably 10 ⁻⁶ g / m ² / day or less.

  As an example of the material of the resin layer 16b, a photocurable adhesive resin, a thermosetting adhesive resin, a two-component curable adhesive resin made of epoxy resin, acrylic resin, silicone resin, or the like, or ethylene ethyl acrylate (EEA) ) Acrylic resins such as polymers, vinyl resins such as ethylene vinyl acetate (EVA), thermoplastic resins such as polyamide and synthetic rubber, and thermoplastic adhesive resins such as acid-modified products of polyethylene and polypropylene. . Examples of methods for forming a resin layer on a sealing material include solvent solution method, extrusion lamination method, melting / hot melt method, calendar method, nozzle coating method, screen printing method, vacuum laminating method, hot roll laminating method. And so on. A material having a hygroscopic property or an oxygen absorbing property may be contained as necessary. Although the thickness of the resin layer formed on a sealing material is arbitrarily determined by the magnitude | size and shape of the organic EL element to seal, about 5-500 micrometers is desirable. In addition, although it formed as a resin layer on the sealing material here, it can also form directly in the organic EL element side.

  Finally, the organic EL element 10 and the sealing body 16 are bonded together in a sealing chamber. When the sealing body has a two-layer structure of a sealing material and a resin layer, and a thermoplastic resin is used for the resin layer, it is preferable to perform only pressure bonding with a heated roll. When a thermosetting adhesive resin is used, it is preferable to perform heat curing at a curing temperature after pressure bonding with a heated roll. In the case where a photocurable adhesive resin is used, curing can be performed by further irradiating light after pressure bonding with a roll.

  Before or instead of sealing with a sealing body, sealing with an inorganic thin film can be performed, for example, a 150 nm silicon nitride film is formed using a CVD method as a passivation film.

An embodiment of the present invention will be specifically described with reference to FIGS.
As a substrate, a TFT substrate was used in which a glass plate was used as a support, a 300 mm square substrate with a two-inch diagonal panel mounted on two sides, and the number of pixels in one panel was 320 × 240. One side of the substrate 61 is defined as a first straight line, and a side orthogonal to the first straight line is defined as a second straight line (FIG. 6A). 6 and 7, the direction of the substrate is not changed unless otherwise specified. A first electrode corresponding to the lower layer TFT was formed thereon as the first electrode 62 and used as a substrate (FIG. 6B). In the drawing, the first electrode is shown in 8 columns and 8 rows for simplification.

  1 μm of photosensitive polyimide resin was laminated on the substrate by a slit coating method, an opening was formed corresponding to the light emitting region through an exposure / development process, and a grid-like organic partition was formed. The organic barrier rib is composed of a second barrier rib 632 that covers the end of the first electrode formed earlier and is parallel to the second straight line, and a first barrier rib lower portion 631a that is 721 lines parallel to the first straight line. (FIG. 6C). In the figure, 9 lines are simply shown.

  Next, similarly, 4 μm of photosensitive polyimide resin was laminated by a slit coating method, and a striped first partition upper portion 631b was formed above the first partition lower portion 631a through an exposure / development process. This was combined with the lower part of the first partition wall to form a first partition wall 631 having a height of 5 μm (FIG. 7D). Both the first partition and the second partition had a width of 50 μm.

An ink-like polymer hole transport material is disposed in the opening 64, which is a region partitioned by the first partition wall and the second partition wall, by letterpress printing and dried to form a charge transport layer 65a having a thickness of 50 nm. (FIG. 7 (e)). A relief printing method using a polythiophene derivative (PEDOT / PSS) as a polymer hole transport material, dispersed in water to form an ink, and using a polyamide-based water-developable photosensitive resin as a printing plate It went by.
The printing plate used here was provided with a line-shaped convex portion corresponding to the second partition as an image portion, and was printed after alignment with the second partition. The printing plate on which the image line portion corresponding to the second partition was formed was set so that the curve direction of the printing cylinder and the second partition (that is, the second straight line) direction coincided. Moreover, the base body provided with the partition which is a to-be-printed substrate was set to the relief printing machine so that the 2nd partition might become a printing direction.
At this time, the image area of the relief plate was printed over the first partition, but the first partition was sufficiently high so that the ink on the partition was separated naturally and did not continue. In addition, since the image line portion of the printing plate was previously separated from the opening adjacent to the second partition wall, there was no leakage.
In the method of the present invention, alignment in the first linear direction is not required, so that the manufacturing process can be shortened and the yield of the organic EL element obtained can be improved.

  Next, an organic light-emitting material is disposed on the charge transport layer 65a by a relief printing method, and dried to form an organic light-emitting layer 65b having a thickness of 80 nm. The organic light-emitting medium layer 65 is completed together with the charge transport layer ( FIG. 7 (f)). For this formation, an ink prepared by dissolving a polyphenylene vinylene derivative, which is a polymer light emitting material, in toluene so as to have a concentration of 1% as an organic light emitting material was used, and a polyamide-based water-developable photosensitive resin was used as a printing plate. It was performed by letterpress printing.

FIG. 8 is a diagram schematically showing a state where the organic light emitting layer is printed by a relief printing method.
The relief plate which is the printing plate 81 used here is provided with a convex portion which is a line-shaped image line portion 81a corresponding to the first partition, and after inking, alignment with the first partition 631 is performed for printing. did. The printing plate 81 on which the image line portion 81a corresponding to the first partition was formed was set so that the curve direction of the printing cylinder 82 and the first partition (that is, the first straight line) direction coincided. Moreover, the base body provided with the partition which is a to-be-printed substrate was set to the relief printing machine so that a 1st partition might become a printing direction. 8B is a cross-sectional view taken along the line AA ′ in FIG. 8A, and is a cross-sectional view taken along the line BB ′ or CC ′ in FIG.
At this time, the relief image area 81a passes over the second partition 632 and performs printing. However, since the second partition is lower than the first partition 631, there is little influence on the printing plate 81, and the printing plate 81 and the printing target are printed. The distance from the substrate 85 can be reduced, and ink can be prevented from remaining on the printing plate. Further, since the ink on the image area 81a can be naturally removed by the second partition 632, the ink did not remain on the partition.
Since the method of the present invention does not require alignment in the second linear direction, the manufacturing process can be shortened and the yield of the organic EL elements obtained can be improved.

A second electrode was prepared by laminating 5 nm of Ca and 100 nm of Al on the organic light-emitting medium layer formed using the relief printing method by resistance heating vapor deposition in vacuum.
The active matrix driving type organic light emitting EL element having 76800 pixels thus formed was sealed with a glass cap, and the first electrode was used as an anode, the second electrode was used as a cathode, and light emission was observed from the first electrode side. No crosstalk due to leakage was observed.

An organic EL device was produced in the same manner as in Example 1 except that the height of the first partition was 3 μm and the height of the second partition was 1 μm.
The active matrix driving type organic light emitting EL element thus formed was sealed with a glass cap, and light emission was observed using the first electrode as an anode and the second electrode as a cathode, and light emission was observed from the first electrode side. Was not observed.

[Comparative Example 1]
Similar to Example 1, the second partition and the lower part of the first partition were formed. Thereafter, the organic EL element was manufactured without forming the upper part of the first partition. The heights of the first partition and the second partition included in the obtained organic EL element are each 1 μm.
The active matrix driving type organic light emitting EL element thus formed was sealed with a glass cap, and the first electrode was used as an anode, the second electrode was used as a cathode, and light emission was observed from the first electrode side. However, crosstalk due to current leakage was observed.

[Comparative Example 2]
An organic EL device was produced in the same manner as in Example 1 except that the hole transport layer was printed in the same direction as the organic light emitting layer in parallel with the first partition.
The active matrix driving type organic light emitting EL element thus formed was sealed with a glass cap, and the first electrode was used as an anode, the second electrode was used as a cathode, and light emission was observed from the first electrode side. However, crosstalk due to current leakage was observed .

(A) It is sectional drawing of one Example of the organic EL element of this invention. (B) It is sectional drawing of an example of the board | substrate which can be used by this invention. It is a perspective view of an example of a substrate which can be used in the present invention. It is a top view of the other example of the base | substrate which can be used by this invention. It is a schematic diagram explaining an example of the printing method which can be used by this invention. It is a schematic diagram explaining the other example of the printing method which can be used by this invention. It is process drawing which shows one Embodiment of the manufacturing method of this invention. It is process drawing which shows one Embodiment of the manufacturing method of this invention. It is explanatory drawing which shows one Embodiment of the manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Organic EL element 11: Board | substrate 12: 1st electrode 13: Partition 14: Organic light emission medium layer 15: 2nd electrode 16: Sealing body 16a: Sealing material 16b: Resin layer 111: Support body 112: Active layer 113 : Gate insulating film 114: gate electrode 115: interlayer insulating film 116: drain electrode 117: planarization layer 118: contact hole 119: data line 120: thin film transistor 20 and 30: substrate 21: substrate 22 and 31: first electrode 23, 32: Second partition wall 24, 33: First partition wall 41: Ink tank 42: Ink chamber 43: Anilox roll 44: Ink 45: Letter plate 46: Plate cylinder 47: Stage 48: Printed substrate 51: Blanket cylinder 52: Silicone blanket 53: Laminated material 53a: Laminated material 53b: Laminated material 53c: Organic functional thin film 54: Convex printing plate 54a: Convex part 55: Printed substrate 61: Substrate 62: First electrode 631: First partition 631a: First partition lower part 631b: First partition upper part 632: Second partition 64: Opening 65: Organic light emission Medium layer 65a: Charge transport layer 65b: Organic light emitting layer 81: Printing plate (letter plate) 81a: Image line part (convex part) 81b: Non-image line part (recessed part) 82: Printing cylinder 83: Support body 84: Ink 85: Printed substrate

Claims (3)

At least a substrate, a first electrode provided on the substrate, a partition formed corresponding to the first electrode, a charge transport layer and an organic light emitting layer formed in a region partitioned by the partition, A method for producing an organic electroluminescence device comprising two electrodes,
The partition is a lattice formed of a first partition parallel to the first straight line and a second partition parallel to the second straight line, the first partition having a height higher than the second partition,
Forming a charge transport layer by a printing method using a printing plate having an image line corresponding to the second partition;
And a step of forming an organic light emitting layer by a printing method using a printing plate having an image line portion corresponding to the first partition. A method for producing an organic electroluminescent element.   2. The method of manufacturing an organic electroluminescent element according to claim 1, wherein the height of the first partition is greater than 1 [mu] m.   3. The method for producing an organic electroluminescent element according to claim 1, wherein the step of forming the charge transport layer and the organic light emitting layer is a relief printing method using a relief plate as a printing plate.

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