WO2013121505A1

WO2013121505A1 - Organic electroluminescent panel and method for manufacturing same

Info

Publication number: WO2013121505A1
Application number: PCT/JP2012/053283
Authority: WO
Inventors: 直井　太郎
Original assignee: パイオニア株式会社; 三菱化学株式会社
Priority date: 2012-02-13
Filing date: 2012-02-13
Publication date: 2013-08-22

Abstract

This organic EL panel has a substrate, and on the substrate, at least one organic functional layer is formed by scanning performed by a droplet jetting nozzle, said organic functional layer being disposed between a first electrode layer and a second electrode layer facing each other, and demarcating a light emitting area. The organic EL panel has a plurality of auxiliary electrodes that are disposed in parallel in stripes on the first electrode layer. The organic functional layer is configured of a plurality of strip-like organic layers, which are disposed among the auxiliary electrodes in parallel to the longitudinal direction of the auxiliary electrodes, and which have end portions thereof bonded to each other. The end portions of the strip-like organic layers are within a normal plane of the substrate, said normal plane including the auxiliary electrodes.

Description

Organic electroluminescence panel and manufacturing method thereof

The present invention relates to an organic EL panel having an organic electroluminescence (hereinafter referred to as organic EL) material as a light emitting layer and a method for manufacturing the same.

An organic EL panel is a surface light emitter in which a plurality of organic functional layers made of an organic compound having a charge transport property are sandwiched between an anode and a cathode, and at least one light emitting layer is included in the organic functional layer.

Organic EL panels have been put into practical use as display devices such as mobile phones, and are being applied to lighting fixtures as thin surface light sources.

As a method for forming an organic functional layer when manufacturing an organic EL panel, a coating method (inkjet method) by scanning a droplet discharge nozzle is known. In the ink jet method, a liquid containing an organic material is ejected through a nozzle in the form of a micro flow (jet flow or drop flow) to deposit droplets on the anode, and then dried to obtain a hole injection layer, a positive Organic functional layers such as a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are formed and stacked.

Conventionally, in an organic EL display device manufactured using an ink jet method, light emission unevenness has occurred at a boundary portion between coating layers of an organic EL material applied by a plurality of scans in the image display area. The uneven light emission at the boundary part deteriorates the “look” of the screen of the organic EL display device that the observer gazes at. In view of this, various ink jet methods have been proposed in which the boundary portion that is an obstacle, that is, the joint portion of the coating layer, is made uniform to make it difficult to visually recognize light emission unevenness (see Patent Documents 1 to 6).

Even when the inkjet method used in the manufacture of a conventional organic EL display device is applied to the manufacture of an organic EL panel for a surface light source, the boundary portion becomes inconspicuous if a plurality of inkjet heads are arranged and scanned simultaneously. However, the use of a plurality of ink jet heads causes an increase in cost and size of manufacturing equipment. There is also a method to increase the width of the inkjet head by increasing the size, but currently there are many 3 to 7 cm wide inkjet heads available, and the wide and large heads are custom-made, making the head expensive and manufactured. Cost increases. Even with the conventional ink jet method, it is difficult to completely eliminate the seam portion, and it is difficult to suppress the non-uniformity of the light emitting surface due to uneven light emission of the seam by suppressing the increase in the manufacturing cost of the organic EL panel for the surface light source. .

JP 2004-327241 A JP 2006-68598 A JP 2008-249781 A JP 2009-66526 A JP 2011-54386 A JP 2006-7079 A

The present invention has been made in view of the above points, and provides an organic EL panel in which nonuniformity of a light emitting surface due to light emission unevenness of a joint of a coating layer generated by an ink jet method is suppressed, and a method for manufacturing the same. An example of the problem.

In the organic EL panel of the present invention, at least one organic functional layer disposed on the substrate and between the first electrode layer and the second electrode layer facing each other in the normal direction of the substrate is scanned by the droplet discharge nozzle. An organic EL panel formed by
A plurality of auxiliary electrodes juxtaposed on the first electrode layer;
The organic functional layer is composed of a plurality of band-like organic layers juxtaposed in parallel with each other between the auxiliary electrodes in the longitudinal direction of the auxiliary electrodes, and edges are joined to each other, and the edge of the band-like organic layer is the auxiliary It lies in the normal plane of the substrate including the electrodes.

Further, in the method for producing an organic EL panel of the present invention, at least one organic functional layer disposed on the substrate and between the first electrode layer and the second electrode layer facing each other in the normal direction of the substrate is a liquid. A method of manufacturing an organic EL panel formed by scanning a droplet discharge nozzle,
Juxtaposing a plurality of auxiliary electrodes on the first electrode layer;
The first electrode between the auxiliary electrodes is scanned over the first electrode layer by a droplet discharge nozzle that moves parallel to the extension direction of the auxiliary electrode along the surface of the first electrode layer between the auxiliary electrodes. And a scanning step of applying a strip organic layer on the electrode layer,
In the scanning step, the droplet discharge nozzle is formed so that the edges of the adjacent strip organic layers applied to each other are bonded to each other and the edges of the strip organic layer are within the normal plane of the substrate including the auxiliary electrode. As described above, the position is controlled relative to the substrate.

According to the present invention, the organic EL panel is provided with an auxiliary electrode that supplies a current to the first electrode layer using a transparent electrode material on the first electrode layer on the light extraction side, and the joint and auxiliary of the coating layer by scanning by the ink jet method. By overlapping both electrodes, the seam becomes inconspicuous.

It is a top perspective view which shows the structure of the organic electroluminescent panel of embodiment of this invention. FIG. 2 is a partial cross-sectional view taken along line AA in FIG. 1. It is sectional drawing which shows the board | substrate in the manufacture process of an organic electroluminescent panel, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacture process of an organic electroluminescent panel, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacture process of an organic electroluminescent panel, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacture process of an organic electroluminescent panel, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacture process of an organic electroluminescent panel, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacture process of an organic electroluminescent panel, and the structure formed on it. It is a schematic perspective view which shows the structure of the inkjet coating device used when forming a strip | belt-shaped organic layer with the inkjet method. It is a perspective view which shows an example of the movement form of the inkjet head which moves on the surface of the board | substrate with which the auxiliary electrode is formed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a portion of an organic EL panel according to an embodiment of the present invention as viewed from the upper surface on the cathode side, and FIG. 2 is a partial cross-sectional view showing a cross section of the organic EL panel taken along line AA in FIG. It is.

In the present embodiment, as shown in FIG. 2, a transparent anode 2 (first electrode layer) formed on a flat substrate 1 or a film-like transparent substrate 1 made of glass, resin, or the like, and laminated thereon. This is an organic EL panel having an organic EL laminate OEL including a light emitting layer 5 and a cathode 9 (second electrode layer) laminated thereon. The organic EL laminated body OEL is formed by laminating an organic functional layer composed of a plurality of band-like organic layers OG formed and connected by an ink jet method, and the hole injection layer 3 / the hole transport layer 4 are used as the organic functional layer. / Light emitting layer 5 / hole blocking layer 6 / electron transport layer 7 / electron injection layer 8 1 and 2, a transparent anode 2 extending in the XY direction on the panel plane is formed on a substrate 1. A solid film-like cathode 9 is formed on the electron injection layer 8 of the organic EL laminate OEL. Note that it is not necessary to form all the organic functional layers of the organic EL panel by the ink jet method, and the film can be formed by another wet method or a vapor deposition method. For example, the hole injection layer and the hole transport layer may be uniformly formed as a solid film by a spray method or the like. For example, the hole blocking layer, the electron transport layer, and the electron injection layer cathode may be uniformly and sequentially formed as a solid film by an evaporation method or the like. Film formation by an ink jet method is preferable for at least a light emitting layer having a large influence on light emission unevenness.

As shown in FIG. 2, on the anode 2, a plurality of auxiliary electrodes BL are formed in stripes parallel to the X direction. In other words, the organic EL stacked body OEL is formed on the substrate 1 on the anode 2 between the adjacent auxiliary electrodes BL so as to straddle the auxiliary electrodes BL. The auxiliary electrode BL is covered with an insulating film SF made of an insulating material (however, only the auxiliary electrode BL is shown in FIG. 1 and the insulating film is not shown). The auxiliary electrode BL is formed to supply power to the anode 2. The organic EL panel uses a transparent electrode for the first electrode layer such as the anode 2 on the light extraction side. Since the transparent electrode has a high resistivity, in an organic EL panel for a surface light source that requires a certain area, an auxiliary electrode made of a metal material having a low resistivity is juxtaposed in a stripe shape on the transparent electrode. In addition, the resistance of the transparent anode 2 as a whole is reduced.

As shown in FIG. 2, each organic functional layer of the organic EL laminate OEL includes a plurality of strip-like organic layers OG that are juxtaposed in parallel to the longitudinal direction (X direction) of the auxiliary electrodes BL and joined to each other between the auxiliary electrodes BL. Consists of An edge portion where adjacent ones of the band-shaped organic layers OG are joined to each other is a joint SM that is in contact with and connected on the auxiliary electrode BL. That is, the edges of the strip-shaped organic layer OG are in the normal plane of the substrate 1 including the auxiliary electrode BL. In addition, the edge part of the strip | belt-shaped organic layer OG means the edge part extended | stretched in a longitudinal direction (X direction).

According to the present embodiment, the joint SM portion by scanning of the inkjet head and the auxiliary electrode BL of the transparent anode 2 are arranged at the same position, that is, the joint SM portion of the plurality of coated strip-like organic layers OG is organic EL laminated. By disposing the joint SM in the normal plane of the substrate 1 including the auxiliary electrode BL in the body OEL, the above-mentioned joint SM portion can be hidden by the auxiliary electrode BL, thereby reducing the deterioration factor of the “look” of the organic EL panel. .

The organic EL panel manufacturing process will be described with reference to FIGS.

As shown in FIG. 3, a parallel plate substrate 1 such as cleaned glass is prepared, on which an anode 2 such as ITO and an auxiliary electrode BL such as aluminum are formed by sputtering or photolithography. A plurality of strip-like auxiliary electrodes BL extending in parallel with the X direction on the surface of the anode 2 are formed at a constant pitch _PBL . The auxiliary electrode BL is formed such that its width W _BL is considerably smaller than the juxtaposed pitch P _BL (W _BL << P _BL ).

Then, as shown in FIG. 4, an insulating insulating film SF is formed for each auxiliary electrode BL so as to expose only the auxiliary electrode BL while exposing the anode 2 by a photolithography process. The insulating film SF is made of a material that can be patterned by exposure and development using, for example, photosensitive polyimide or novolac resin. The insulating film SF usually contains an ethylenically unsaturated compound, a photopolymerization initiator, and a solvent, and may further contain a binder resin, a crosslinking agent, a surface modifier, a liquid repellent component, and the like.

Then, as shown in FIG. 5, droplets of a solution of the material constituting the hole injection layer of the organic functional layer are formed on the insulating film SF and the anode 2 from a droplet discharge nozzle (not shown) of the inkjet head 12. Lq is supplied. In the inkjet coating process, the inkjet head 12 moves on the anode 2 between the auxiliary electrodes BL while moving in parallel with the extension direction of the auxiliary electrode BL (X direction: scanning direction) between adjacent auxiliary electrodes BL and scanning the surface. The strip organic layer OG is applied to After the scanning application between one auxiliary electrode BL, the inkjet head is moved in the Y direction at the end of the substrate 1 and sequentially applied by scanning between adjacent auxiliary electrodes BL. Edges (extending in the scanning direction) of the adjacent strip-shaped organic layers OG applied are connected in contact with each other and joined together to form a joint SM on each auxiliary electrode BL.

Thereafter, the organic layer is subjected to a drying process, and as shown in FIG. 6, the hole injection layer 3 in which the edges of the band-shaped organic layer OG are connected by the joint SM is formed.

Then, a combination of an inkjet coating process and a drying process is sequentially repeated for each organic functional layer that performs each function, and as shown in FIG. 7, a multilayer organic EL in which the edges of each strip-shaped organic layer are connected by a joint SM. A laminated body OEL (hole injection layer 3 / hole transport layer 4 / light emitting layer 5 / hole blocking layer 6 / electron transport layer 7 / electron injection layer 8) is formed.

Then, as shown in FIG. 8, after the organic EL laminate OEL is formed, a metal film cathode 9 is formed by vapor deposition or the like. A portion where the anode 2 and the cathode 9 overlap with each other sandwiching the organic EL laminate OEL defines a light emitting area of the organic EL panel.

Thereafter, a sealed organic EL panel can be obtained through a sealing process.

FIG. 9 is a schematic perspective view showing a configuration of an ink jet coating apparatus that coats a band-shaped organic layer in an ink jet coating process.

As shown in FIG. 9, the inkjet coating apparatus includes a stage 10 that fixes the substrate 1, a stage moving mechanism 11 that moves the stage 10 in the Y direction, an inkjet head 12, and the inkjet head 12 in the X direction orthogonal to the Y direction. A head moving mechanism 13 for moving is provided. The ink jet coating apparatus also includes a control unit (not shown) that drives the stage moving mechanism 11, the ink jet head 12, and the head moving mechanism 13. The inkjet head 12 is provided with a plurality of droplet discharge nozzles (not shown) for discharging droplets containing an organic material as a raw material such as the hole injection layer 3 toward the surface of the substrate 1. . The control unit controls the movement of the stage moving mechanism 11 and the head moving mechanism 13 to move the inkjet head 12 in the Y direction and the X direction in the space above the substrate 1 fixed to the stage 10. Further, the control unit controls the ejection of droplets with respect to the inkjet head 12. The viscosity of the droplet containing the organic material ejected by the inkjet head 12 is 2 to 5 cp, and the surface tension is 30 to 40 mN / m. Moreover, the boiling point of this organic material is larger than 200 degreeC. Furthermore, the droplet discharge speed by the inkjet head 12 is, for example, about 4 m / sec, the discharge amount is about 15 ml, and the drive frequency is about 5 to 12 kHz. The moving speed of the inkjet head 12 is about 100 mm / sec.

As the inkjet head 12, an on-demand piezo type composed of a plurality of piezo elements can be used. Each solution tank (not shown) corresponding to each organic functional layer is connected to the inkjet head. For example, each of a plurality of droplet discharge nozzles in an inkjet head is formed with a piezo element having a solution chamber having a piezoelectric ceramic wall communicating with the nozzle. Pressure is applied to the solution by expansion and contraction of the solution chamber in accordance with the applied voltage to each piezo element, and the solution filled in each solution chamber is discharged from a plurality of nozzles (not shown) of the piezo element. As shown in FIG. 10, for example, according to the inkjet head 12 provided with several hundreds of nozzles arranged in parallel in the Y direction, a plurality of droplets Lq of the solution are provided for the number of nozzles arranged in the Y direction. The strip-shaped organic layer OG can be applied on the anode 2 with a width (W _OG ).

The ink jet head 12 controlled by the control unit is moved to one end Q1 of the substrate 1 shown in FIG. 10 and moved from the position toward the other end Q2 of the substrate 1 in the X direction. The ejection of droplets by the head 12 is executed. As a result, droplets of the organic material discharged from the inkjet head 12 adhere to the area scanned by the inkjet head 12. In this case, the pitch P _BL auxiliary electrodes BL which coincides with the pitch P _OG of the strip-shaped organic layer OG is previously formed so as to extend parallel to the X direction, the anode therebetween and adjacent auxiliary electrodes BL to each other Only the area above 2 (under the path Q1-Q2) is coated with organic material droplets. In addition, the edge part of the board | substrate 1 means the edge part extended | stretched in a Y direction.

When the inkjet head 12 reaches a position outside the end portion Q2 of the substrate 1 shown in FIG. 10, the ejection of the liquid droplets is stopped and moves relative to the substrate 1 in the Y direction toward the end portion Q3 of the substrate 1. The position Q3 shown in FIG. 10 is reached. Then, the inkjet head 12 again causes the inkjet head 12 to discharge the droplet Lq while moving from the position of the end Q3 of the substrate 1 toward the end Q4 of the substrate 1 in the X direction. As a result, organic material droplets are deposited only in the region on the anode 2 (under the Q3-Q4 path) between the auxiliary electrodes BL adjacent to each other.

As shown in FIG. 5 and FIG. 6, the inkjet head 12 is moved along the longitudinal direction (X direction) between the auxiliary electrodes BL while discharging the droplets by the inkjet head 12. A seam SM is formed in which the edges of the regions between the adjacent auxiliary electrodes BL (applied adjacent band-like organic layers OG) are in contact with each other.

As described above, the method for manufacturing the organic EL panel according to the embodiment includes a step of forming a plurality of auxiliary electrodes BL juxtaposed in a stripe shape on the anode 2, as shown in FIG. As shown in FIG. 5, the method includes a scanning process in which the band-shaped organic layer OG is applied on the anode 2 between the auxiliary electrodes BL while the inkjet head 12 is scanned in parallel with the extension direction of the auxiliary electrode BL between the auxiliary electrodes BL. In the scanning process, the ink jet head 12 (droplet discharge nozzle) forms a joint SM in which the edges of the applied adjacent strip organic layers OG are in contact with each other on or just above the auxiliary electrode BL. The position is controlled relative to the substrate 1.

Furthermore, as shown in FIG. 7, the organic functional layer (hole injection layer 3 / hole transport layer 4 / light emitting layer 5 / hole blocking layer 6 / electron transport layer 7) corresponding to the step of applying the strip organic layer OG is applied. In each of the scanning steps shown in FIG. 5, the inkjet head 12 (droplet discharge nozzle) is present in the normal plane including the auxiliary electrode BL of the substrate 1 in each of the scanning steps shown in FIG. In this way, the position is controlled relative to the substrate 1.

Moreover, in the said embodiment, although the light emitting layer 5 which consists of the mixed organic EL material can be made into one layer, the organic electroluminescent panel of monochromatic light emission, such as white, red, green, blue, can be produced, In addition to this, it consists of a multilayer light emitting layer. An organic EL panel can be produced. For example, a light-emitting layer that emits red light, a light-emitting layer that emits green light, and a light-emitting layer that emits blue light can be sequentially stacked to produce a white light-emitting organic EL panel including three light-emitting layers. In addition, a light-emitting layer that emits yellow-orange light and a light-emitting layer that emits blue light can be sequentially stacked to produce a white light-emitting organic EL panel including two light-emitting layers.

Therefore, according to the present embodiment, by making the joint position by scanning of the inkjet head for applying the organic EL material the same as the auxiliary electrode position of the transparent electrode, the joint part can be hidden by the auxiliary electrode, At least, it can reduce the deterioration factor of “look”. In addition, since the number of heads mounted on the ink jet coating apparatus can be reduced, apparatus cost and apparatus size can be reduced. In addition, an ink jet head that can be obtained at present can be used, and it is possible to provide an organic EL panel that can suppress an unnecessary cost increase such as a custom head.

An example of the organic EL panel of the present embodiment is, as shown in FIG. 2, an anode 2 / hole injection layer 3 / hole transport layer 4 / light emitting layer that are sequentially laminated on a transparent substrate 1 such as glass. 5 / hole blocking layer 6 / electron transport layer 7 / electron injection layer 8 / cathode 9 /. In addition to this laminated structure, although not shown, an anode 2 / hole injection layer 3 / light emitting layer 5 / electron transport layer 7 / electron injection layer 8 / cathode 9 / hole transport layer 4 and hole blocking layer 6 are provided. Although omitted, and not shown, the anode 2 / hole transport layer 4 / light emitting layer 5 / electron transport layer 7 / electron injection layer 8 / cathode 9 / hole injection layer 3 and hole blocking layer 6 are omitted. Although not shown in the figure, the anode 2, the light emitting layer 5, the electron transport layer 7, the electron injection layer 8, the cathode 9 / the hole injection layer 3, the hole transport layer 4, and the hole blocking layer 6 may be omitted. It is included in the present invention. Moreover, in the layer structure demonstrated above, it is also possible to laminate | stack components other than a board | substrate in reverse order. In any case, the present invention is not limited to these laminated structures, and a laminated structure including at least a light-emitting layer or a charge transport layer that can also be used is also included in the invention.

[substrate]
As the substrate 1, a quartz or glass plate, a metal plate or a metal foil, a resin substrate to be bent, a plastic film, a sheet, or the like is used. In particular, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic EL panel may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

[Anode and cathode]
The anode 2 that supplies holes to the layers up to the light emitting layer is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum, or a metal such as indium and / or tin or zinc oxide (ITO or IZO). It is composed of an oxide, a metal halide such as copper iodide, carbon black, or a conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline.

The anode is usually formed by a sputtering method, a vacuum deposition method, or the like. In addition, when forming an anode using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, or conductive polymer fine powder, an appropriate binder resin solution is used. The anode can also be formed by dispersing and coating the substrate. Further, in the case of a conductive polymer, a thin film can be directly formed on the substrate by electrolytic polymerization, or the anode can be formed by applying a conductive polymer on the substrate.

The anode usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.

The thickness of the anode depends on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably about 500 nm or less. If it may be opaque, the thickness of the anode is arbitrary, and the anode may be integrated with the substrate 1. Furthermore, different conductive materials may be laminated.

The surface of the anode is treated with ultraviolet (UV) / ozone, oxygen plasma, or argon plasma for the purpose of removing impurities adhering to the anode and adjusting the ionization potential to improve hole injection. Is preferred.

As a material of the cathode 9 for supplying electrons to the layers up to the light emitting layer, a material used for the anode can be used. However, in order to perform electron injection efficiently, a metal having a low work function is preferable. A suitable metal such as tin, magnesium, indium, calcium, aluminum, silver, or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In addition, only 1 type may be used for the material of the

cathode

9, and 2 or more types may be used together by arbitrary combinations and a ratio. The thickness of the cathode is usually the same as that of the anode.

Further, for the purpose of protecting the cathode made of a low work function metal, it is preferable to further laminate a metal layer having a high work function and stable to the atmosphere because the stability of the organic EL panel is increased. For this purpose, for example, metals such as aluminum, silver, copper, nickel, chromium, gold, platinum are used. In addition, these materials may be used only by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

Furthermore, when the anode and cathode are on the light emission extraction side (first electrode layer), the material and film thickness are selected so as to be transparent or translucent. In particular, it is preferable to select a material in which either one or both of the anode and the cathode has a transmittance of at least 10% at the emission wavelength obtained from the organic light emitting material.

[Organic functional layer]
* Hole injection layer *
The hole injection layer 3 is preferably a layer containing an electron accepting compound.

The film thickness of the hole injection layer is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. The hole injection layer is preferably formed by a wet film formation method such as an inkjet method from the viewpoint of reducing dark spots.

When forming a hole injection layer by a wet film formation method, the material for forming the hole injection layer is usually mixed with an appropriate solvent (a solvent for the hole injection layer) to form a composition for film formation (hole An injection layer forming composition) is prepared, and this hole injection layer forming composition is coated on the anode by an appropriate technique to form a film and dried to form a hole injection layer.

The composition for forming a hole injection layer usually contains a hole transporting compound and a solvent as a constituent material of the hole injection layer. Examples of the solvent include, but are not limited to, ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, and the like.
Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2 -Aromatic toluene such as methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and the like.

Examples of ester solvents include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.

Examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylpropylphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene. Can be mentioned.

Examples of the amide solvent include N, N-dimethylformamide and N, N-dimethylacetamide. In addition, dimethyl sulfoxide and the like can also be used. These solvent may use only 1 type and may use 2 or more types by arbitrary combinations and a ratio.

As long as the hole transporting compound is a compound having a hole transporting property that is usually used in a hole injection layer of an organic EL panel, a polymer or the like may be a monomer or the like. Although it may be a low molecular compound, it is preferably a low molecular compound.

The hole transporting compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of a charge injection barrier from the anode to the hole injection layer. Examples of hole transporting compounds include aromatic amine derivatives, phthalocyanine derivatives typified by phthalocyanine copper (CuPc), porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, and tertiary amines linked by fluorene groups. Examples thereof include compounds, hydrazone derivatives, silazane derivatives, silanamine derivatives, phosphamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, and carbon.

Here, the derivative includes, for example, an aromatic amine derivative, and includes an aromatic amine itself and a compound having an aromatic amine as a main skeleton. It may be a body.

The hole transporting compound used as the material for the hole injection layer may contain any one of these compounds alone, or may contain two or more. In the case of containing two or more kinds of hole transporting compounds, the combination is arbitrary, but one or more kinds of aromatic tertiary amine polymer compounds and one or two kinds of other hole transporting compounds. The above can also be used together. From the viewpoints of amorphousness and visible light transmittance, an aromatic amine compound is preferable for the hole injection layer, and an aromatic tertiary amine compound is particularly preferable. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine. Specific examples include those described in the pamphlet of International Publication No. 2005/089024.

As the hole transporting compound, a conductive polymer (PEDOT / PSS) obtained by polymerizing 3,4-ethylenedioxythiophene, which is a derivative of polythiophene, in high molecular weight polystyrene sulfonic acid is also preferable. Moreover, the end of this polymer may be capped with methacrylate or the like.

The concentration of the hole transporting compound in the composition for forming a hole injection layer is usually 0.01% by weight or more, preferably 0.1% by weight or more, and more preferably 0.00% by weight in terms of film thickness uniformity. 5% by weight or more, usually 70% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. If this concentration is too high, film thickness unevenness may occur, and if it is too low, defects may occur in the formed hole injection layer.

The composition for forming a hole injection layer preferably contains an electron-accepting compound, and may further contain other components in addition to the hole-transporting compound and the electron-accepting compound. Examples of other components include various light emitting materials, electron transporting compounds, binder resins, and coating property improving agents. In addition, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and ratios.

* Hole transport layer *
The material of the hole transport layer 4 may be any material that has been conventionally used as a constituent material of the hole transport layer. For example, the hole transport layer is exemplified as the hole transport compound used in the above-described hole injection layer. Things. In addition, arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, condensed polycyclic aromatics Group derivatives, metal complexes and the like. Also, for example, polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylene derivatives, polysiloxane derivatives, polythiophenes Derivatives, poly (p-phenylene vinylene) derivatives, and the like. These may be any of an alternating copolymer, a random polymer, a block polymer, or a graft copolymer. Further, it may be a polymer having a branched main chain and three or more terminal portions, or a so-called dendrimer.

Specific examples of the material for the hole transport layer 4 include polyarylene derivatives described in JP-A-2008-98619.

When the hole transport layer is formed by a wet film formation method, a composition for forming a hole transport layer is prepared in the same manner as the formation of the hole injection layer, followed by drying after the wet film formation.

In addition to the hole transporting compound, the hole transporting layer forming composition contains a solvent. The solvent used is the same as that used for the composition for forming the hole injection layer. The film forming conditions, the drying conditions, and the like are the same as in the case of forming the hole injection layer.

The hole transport layer may contain various light emitting materials, electron transport compounds, binder resins, coatability improvers and the like in addition to the hole transport compound.

The film thickness of the hole transport layer is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

The hole transport layer may be formed by a vacuum deposition method or a wet film formation method, but is preferably formed by a wet film formation method from the viewpoint of reducing dark spots.

The hole transport layer 4 may be a layer containing a polymer obtained by crosslinking an amine-based crosslinking compound.

* Light emitting layer *
The light emitting layer 5 contains at least a material having a light emitting property (light emitting material) as a constituent material, and preferably a compound having a hole transporting property (hole transporting compound) or an electron transport. A compound (electron transporting compound) having the following properties: A light emitting material may be used as a dopant material, and a hole transporting compound, an electron transporting compound, or the like may be used as a host material. There is no particular limitation on the light-emitting material, and a material that emits light at a desired light emission wavelength and has favorable light emission efficiency may be used. In addition, when forming a light emitting layer with a wet film-forming method, it is preferable to use a low molecular weight material in any case.

Any known material can be applied as the light emitting material. For example, a fluorescent material or a phosphorescent material may be used, but a phosphorescent material is preferred from the viewpoint of internal quantum efficiency. Alternatively, blue may be used in combination, such as using a fluorescent material, and green and red using a phosphorescent material.

For the purpose of improving the solubility in a solvent, it is preferable to reduce the symmetry and rigidity of the molecule of the luminescent material, or to introduce a lipophilic substituent such as an alkyl group.

Examples of fluorescent light emitting materials (blue fluorescent dyes) that emit blue light include naphthalene, perylene, pyrene, chrysene, anthracene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof.

Examples of the fluorescent light-emitting material (green fluorescent dye) that emits green light include aluminum complexes such as quinacridone derivatives, coumarin derivatives, and Alq3 (tris (8-hydroxy-quinoline) aluminum).

Examples of the fluorescent light emitting material (yellow fluorescent dye) that emits yellow light include rubrene and perimidone derivatives.

Examples of fluorescent materials that emit red light (red fluorescent dyes) include DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, Examples include benzothioxanthene derivatives and azabenzothioxanthene.

As the phosphorescent material, for example, a long-period type periodic table (hereinafter, unless otherwise specified, the term “periodic table” refers to a long-period type periodic table) selected from Group 7 to 11 And an organometallic complex containing a metal. Preferred examples of the metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold. As the ligand of the complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand and a pyridine, pyrazole, phenanthroline, or the like is connected is preferable. A pyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

Specific examples of phosphorescent materials include tris (2-phenylpyridine) iridium (Ir (ppy) 3), tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, and bis (2-phenylpyridine). ) Platinum, tris (2-phenylpyridine) osmium, tris (2-phenylpyridine) rhenium, octaethylplatinum porphyrin, octaphenylplatinum porphyrin, octaethylpalladium porphyrin, octaphenylpalladium porphyrin, and the like.

The molecular weight of the compound used as the light emitting material is usually 10,000 or less, preferably 5000 or less, more preferably 4000 or less, still more preferably 3000 or less, and usually 100 or more, preferably 200 or more, more preferably 300 or more, still more preferably. The range is 400 or more. If the molecular weight of the luminescent material is too small, the heat resistance will be significantly reduced, gas generation will be caused, the film quality will be reduced when the film is formed, or the morphology of the organic functional layer will be changed due to migration, etc. There is a case. On the other hand, if the molecular weight of the luminescent material is too large, it tends to be difficult to purify the organic compound, or it may take time to dissolve in the solvent.

In addition, any 1 type may be used for a luminescent material, and 2 or more types may be used together by arbitrary combinations and a ratio. The ratio of the light emitting material in the light emitting layer is usually 0.05% by weight or more and usually 35% by weight or less. If the amount of the light emitting material is too small, uneven light emission may occur. If the amount is too large, the light emission efficiency may be reduced. In addition, when using together 2 or more types of luminescent material, it is made for the total content of these to be contained in the said range. The component having the highest content in the light emitting layer is called a host material, and the component having a smaller content is called a guest material. Therefore, at least two kinds of solid contents (host material and guest material) to be the light emitting layer can be prepared by being dispersed or dissolved in a solvent as a solute in the light emitting layer coating liquid.

The light emitting layer may contain a hole transporting compound as a constituent material. Here, among the hole transporting compounds, examples of the low molecular weight hole transporting compound include various compounds exemplified as the hole transporting compound in the hole injection layer 3 described above, for example, Two or more condensed aromatic rings containing two or more tertiary amines represented by 4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) are attached to the nitrogen atom. Aromatic amine compounds having a starburst structure (Journal 芳香 of ジアミン Luminescence, such as substituted aromatic diamines (Japanese Patent Laid-open No. Hei 5-234681), 4,4 ', 4 "-tris (1-naphthylphenylamino) triphenylamine) 1997, Vol.72-74, pp.985), aromatic amine compounds consisting of tetramers of triphenylamine (Chemical Communications, 1996, pp.2175), 2,2 ′, 7,7′-tetrakis- ( Diphenylamino) -9, '- spiro compounds such spirobifluorene (Synthetic Metals, 1997, Vol.91, pp.209) and the like.

In addition, in a light emitting layer, only 1 type may be used for a hole transportable compound, and it may use 2 or more types together by arbitrary combinations and a ratio.

The proportion of the hole transporting compound in the light emitting layer is usually 0.1% by weight or more and usually 65% by weight or less. If the amount of the hole transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of hole transportable compounds, it is made for the total content of these to be contained in the said range.

The light emitting layer may contain an electron transporting compound as a constituent material. Here, among the electron transporting compounds, examples of low molecular weight electron transporting compounds include 2,5-bis (1-naphthyl) -1,3,4-oxadiazole (BND), 2,5, -Bis (6 '-(2', 2 "-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), bathophenanthroline (BPhen), 2,9-dimethyl-4,7 Diphenyl-1,10-phenanthroline (BCP, bathocuproin), 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 4 , 4′-bis (9H-carbazol-9-yl) biphenyl (CBP), etc. In the light emitting layer, only one kind of electron transporting compound may be used, or two or more kinds may be used. It may be used in combination with combination and ratio.

The proportion of the electron transporting compound in the light emitting layer is usually 0.1% by weight or more and usually 65% by weight or less. If the amount of the electron transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of electron transport compounds, it is made for the total content of these to be contained in the said range.

The light emitting layer is formed by preparing a composition for forming a light emitting layer by dissolving the above light emitting layer material in an appropriate solvent and forming a film using the composition.

As the solvent for the light emitting layer to be contained in the composition for forming a light emitting layer for forming the light emitting layer by a wet film forming method, any solvent can be used as long as the light emitting layer can be formed. Suitable examples of the solvent for the light emitting layer are the same as those described for the composition for forming a hole injection layer.

The ratio of the light emitting layer solvent to the light emitting layer forming composition for forming the light emitting layer is usually 0.01% by weight or more and usually 70% by weight or less. In addition, when using 2 or more types of solvents mixed as a solvent for light emitting layers, it is made for the sum total of these solvents to satisfy | fill this range.

After forming the light emitting layer forming composition into a wet film, the obtained coating film is dried and the solvent is removed to form a light emitting layer. The light emitting layer is similar to the coating method described in the formation of the hole injection layer, but is preferably formed by a wet film forming method from the viewpoint of reducing dark spots.

The film thickness of the light emitting layer is usually 3 nm or more, preferably 5 nm or more, and usually 200 nm or less, preferably 100 nm or less. If the light emitting layer is too thin, defects may occur in the film, and if it is too thick, the driving voltage may increase.

* Hole blocking layer *
The hole blocking layer 6 is a layer laminated on the light emitting layer so as to be in contact with the cathode side interface of the light emitting layer. The hole blocking layer has a role of blocking holes moving from the anode from reaching the cathode and a role of efficiently transporting electrons injected from the cathode toward the light emitting layer.

The physical properties required for the material constituting the hole blocking layer include high electron mobility, low hole mobility, large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). It is expensive. Examples of the material of the hole blocking layer satisfying such conditions include bis (2-methyl-8-quinolinolato) (4-phenolato) aluminum (PAlq) and bis (2-methyl-8-quinolinolato) (tri Mixed ligand complexes such as phenylsilanolato) aluminum (SAlq), bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, etc. Stylyl compounds such as metal complexes and distyrylbiphenyl derivatives (Japanese Patent Laid-Open No. 11-242996), 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4- Triazole derivatives such as triazole (JP-A-7-41759), phenanthroyl such as bathocuproine (BCP) And the like derivatives (JP-A-10-79297). Furthermore, compounds having at least one pyridine ring substituted at the 2,4,6-positions described in International Publication No. 2005-022962 are also preferable as the material for the hole blocking layer.

In addition, only 1 type may be used for the material of a hole-blocking layer, and 2 or more types may be used together by arbitrary combinations and a ratio. Although there is no restriction | limiting in the formation method of a hole-blocking layer, It is preferable to form by the wet film-forming method from a viewpoint of dark spot reduction.

The film thickness of the hole blocking layer is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

* Electron transport layer *
The electron transport layer 7 is provided for the purpose of further improving the light emission efficiency of the organic EL panel, and efficiently transports electrons injected from the cathode between the electrodes to which an electric field is applied in the direction of the light emitting layer. Formed from a compound capable of

As the electron transporting compound used for the electron transport layer, usually, the electron injection efficiency from the cathode 9 or the electron injection layer 8 is high, and the injected electrons having high electron mobility can be efficiently transported. Use possible compounds. Examples of the compound satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline such as Alq3 (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadi Azole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline Compound (JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous Silicon carbide, n-type sulfide Examples thereof include zinc and n-type zinc selenide.

In addition, only 1 type may be used for the material of an electron carrying layer, and 2 or more types may be used together by arbitrary combinations and a ratio.

The formation method of the electron transport layer is not limited, but it is preferably formed by a wet film formation method from the viewpoint of reducing dark spots.

The film thickness of the electron transport layer is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

* Electron injection layer *
The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode into the light emitting layer. In order to perform electron injection efficiently, the material for forming the electron injection layer is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and their compounds (CsF, Cs ₂ CO ₃ , Li ₂ O, LiF) and the like. .1 nm or more and 5 nm or less are preferable.

Furthermore, an organic electron transport compound typified by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium or rubidium ( As described in JP-A-10-270171, JP-A-2002-1000047, JP-A-2002-1000048, and the like, it is possible to improve the electron injection / transport property and achieve excellent film quality. preferable. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.

In addition, only 1 type may be used for the material of an electron injection layer, and 2 or more types may be used together by arbitrary combinations and a ratio. There is no restriction | limiting in the formation method of an electron injection layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

[Experimental Example 1]
Specifically, in the experiment, an anode (ITO) / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection on the glass substrate by the process described above with reference to FIGS. An organic EL element having a layer structure (LiF) / cathode (Al) / was prepared and evaluated. Note that a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode were formed by an evaporation method.

From the experimental results, it was confirmed that all the seam portions of the organic functional layer are arranged in the normal plane of the substrate including the auxiliary electrode of the substrate, so that the seam portion can be hidden by the auxiliary electrode and the seam is eliminated.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode BL Auxiliary electrode 10 Stage 11 Stage moving mechanism 12 Inkjet head 13 Head moving mechanism

Claims

An organic EL panel in which at least one organic functional layer disposed between a first electrode layer and a second electrode layer facing each other in the normal direction of the substrate is formed by scanning a droplet discharge nozzle. There,
A plurality of auxiliary electrodes juxtaposed on the first electrode layer;
The organic functional layer is composed of a plurality of band-like organic layers juxtaposed in parallel with each other between the auxiliary electrodes in the longitudinal direction of the auxiliary electrodes, and edges are joined to each other, and the edge of the band-like organic layer is the auxiliary An organic EL panel, which is in a normal plane of the substrate including electrodes.
2. The organic EL panel according to claim 1, wherein when there are a plurality of the organic functional layers, all of the edges of the band-shaped organic layer are in a normal plane of the substrate.
An organic EL panel in which at least one organic functional layer disposed between a first electrode layer and a second electrode layer facing each other in the normal direction of the substrate is formed by scanning a droplet discharge nozzle. A manufacturing method,
Juxtaposing a plurality of auxiliary electrodes on the first electrode layer;
The first electrode between the auxiliary electrodes is scanned over the first electrode layer by a droplet discharge nozzle that moves parallel to the extension direction of the auxiliary electrode along the surface of the first electrode layer between the auxiliary electrodes. And a scanning step of applying a strip organic layer on the electrode layer,
In the scanning step, the droplet discharge nozzle is formed so that the edges of the adjacent strip organic layers applied to each other are bonded to each other and the edges of the strip organic layer are within the normal plane of the substrate including the auxiliary electrode. A method for manufacturing an organic EL panel, wherein the position is controlled relative to the substrate.
In the case where a plurality of the organic functional layers are formed by executing the scanning step a plurality of times, in each of the scanning steps, the droplet discharge nozzle is such that all the edges of the band-shaped organic layer are within the normal plane of the substrate. The method of manufacturing an organic EL panel according to claim 3, wherein the position is controlled relative to the substrate.