JP2004043898A - Vapor deposition mask, and organic electroluminescence display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor deposition mask for consistently depositing electrodes of an organic EL display device having sectional shapes not to be raised from a surface to be vapor-deposited and preventing a vapor deposition film from going around with high accuracy, and the organic electroluminescence display device. <P>SOLUTION: The vapor deposition mask for depositing an anode and a cathode of an organic EL display device so as to be orthogonal to each other comprises a frame body 7 to demarcate a mask peripheral part, and a plurality of resin fiber parts 6 stretched between sides facing each other of the frame body 7 along one direction, and a surface in contact with surfaces to be vapor-deposited of the resin fiber parts 6 constitutes a flat portion. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a deposition mask for forming a pattern of an electrode of an organic electroluminescence display device (hereinafter, referred to as an “organic EL display device”) by a vapor deposition method, and an organic EL display device manufactured using the same.
[0002]
[Prior art]
When a pattern is formed by an evaporation method, an evaporation mask made of a thin metal plate having a plurality of openings is generally used. When depositing a deposited film, the particles scattered from the deposition source have directionality, so if the opening of the mask is small and the thickness of the mask is thick, the scattered particles are blocked by the mask, so the part that is difficult to deposit , And unevenness may occur in the deposited film.
[0003]
In addition, since a metal mask has a large specific gravity, the mask hangs down under the influence of gravity, the thickness of the film is uneven due to the floating of the mask, and the width of the deposited film varies from place to place. In the worst case, the deposited film completely wraps around the raised portion of the mask and is continuously formed, so that accurate pattern formation cannot be performed. For this reason, a mask having a devised cross-sectional shape is generally used.
[0004]
Conventionally, a resin fiber mask having a round cross-sectional shape has been used in order to reduce distortion caused by gravity of an evaporation mask. Further, as disclosed in Japanese Patent Application Laid-Open No. 2000-182767, there has been proposed a method of using fibers having a circular cross section, bundling fibers having different diameters, and preventing unevenness in film thickness by devising a cross sectional shape. I have.
[0005]
[Problems to be solved by the invention]
2. Description of the Related Art In recent years, an organic EL display device has been proposed as one of display devices, and practical use thereof is progressing. An organic electroluminescent element (hereinafter, referred to as “organic EL element”) constituting this organic EL display device has a configuration in which at least an anode, an organic material layer, and a cathode are sequentially laminated on a substrate. Electrons are injected from the cathode of the body and holes are injected from the anode, and the applied electric field causes the electrons and holes to move through the thin film and recombine in the organic layer as the light emitting layer, thereby generating the excitation generated. Some of the children lose heat and some emit light when lost. That is, the organic EL element utilizes the phenomenon of light emission when excitons are lost.
[0006]
By the way, it has been found that in the organic EL element, particularly when used for a display device, a difference in luminance occurs due to a difference in the thickness of the vapor-deposited film, and a difference in luminance occurs in a dot. This is because unevenness of the film thickness causes the efficiency of injection of electrons or holes to vary depending on the location, which causes uneven brightness or non-emission when emitting light. Therefore, it is necessary to improve the deposition mask which particularly affects the film thickness distribution.
[0007]
In addition, if the electrode line width changes from place to place due to the wraparound of the deposition film due to the lifting of the deposition mask, the size of the dots varies, and the brightness of each dot varies. This is fatal to an organic EL element used as a display.
[0008]
The present invention has been made in view of the above problems, and has as its object the purpose of preventing the deposition of a deposited film from floating from the surface to be deposited, preventing the electrode of the organic EL display device from being accurately and stably provided. It is an object of the present invention to provide an evaporation mask that can be formed by using the method, and an organic EL display device manufactured using the mask.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the evaporation mask of the present invention has a structure in which at least an anode, an organic material layer containing a luminescent material, and a cathode are laminated on a substrate, and a plurality of rows of anodes are arranged in one direction. And an evaporation mask used to form an anode and a cathode of an organic EL display device in which a plurality of rows of cathodes are arranged along a direction orthogonal to the anode.
A frame that partitions the peripheral portion of the mask, and a plurality of resin fiber portions that are laid in parallel along one direction between opposing sides of the frame, and
The surface of the resin fiber portion that comes into contact with the surface to be deposited constitutes a plane portion.
[0010]
In the vapor deposition mask, it is preferable that a cross-sectional shape of the resin fiber portion is formed such that a width of a plane portion in contact with the surface to be vapor-deposited is larger than a width of a surface portion facing the surface.
[0011]
Further, it is preferable that the cross-sectional shape of the resin fiber portion is such that a width of a plane portion in contact with the surface to be vapor-deposited is larger than a maximum value of a thickness width orthogonal to the surface to be vapor-deposited.
[0012]
Further, the cross-sectional shape of the resin fiber portion is preferably a triangle, a square, a rectangle, a trapezoid, a polygon, or a semicircle.
[0013]
And it is preferable that the said frame and the said resin fiber part are formed with the same kind of resin material.
[0014]
In addition, it is preferable that the frame is reinforced by a reinforcing frame in order to give tension to the resin fiber portion.
[0015]
On the other hand, the organic EL display device of the present invention has at least an anode, an organic material layer containing a luminescent material, and a cathode laminated on a substrate, and a plurality of rows of anodes are arranged along one direction. In an organic EL display device in which a plurality of rows of cathodes are arranged along a direction orthogonal to the anode,
An anode and a cathode are pattern-formed on a substrate so as to be orthogonal to each other by using any one of the above masks for vapor deposition.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments.
[0017]
The vapor deposition mask of the present invention is formed by stacking at least an anode, an organic material layer containing a luminescent material, and a cathode on a substrate, and disposing a plurality of rows of anodes along one direction, and orthogonal to the anodes. This mask is used for manufacturing an organic EL display device in which a plurality of rows of cathodes are arranged along a direction, and forms an anode and a cathode of the organic EL display device so as to be orthogonal to each other.
[0018]
The evaporation mask of the present embodiment includes a frame that partitions the peripheral portion of the mask, and a plurality of resin fiber portions that are laid in parallel in one direction between opposing sides of the frame. Have. In other words, the resin fiber portion is stretched across the opposite sides of the frame body in parallel in a stripe shape, and the surface of the resin fiber portion that contacts the substrate as the surface to be deposited constitutes a flat portion. are doing. And it is preferable that the cross-sectional shape of the resin fiber portion is formed such that the width of a plane portion in contact with the substrate as the surface to be vapor-deposited is larger than the width of the surface portion facing the same. Further, the cross-sectional shape of the resin fiber portion is preferably such that the width of a plane portion in contact with the surface to be vapor-deposited is larger than the maximum thickness width orthogonal to the surface to be vapor-deposited. As a mask for vapor deposition that satisfies such conditions, for example, a mask having a trapezoidal cross section of the resin fiber portion as shown in FIG. Alternatively, a semicircular, square, rectangular, or triangular mask as shown in FIG. 4B or a mask having a polygonal shape or the like can be used.
[0019]
By using a mask in which the surface in contact with the surface to be deposited of such a resin fiber portion constitutes a plane portion, the mask is easily adhered to the surface to be deposited, so that it is possible to prevent the deposition film from wrapping around, particularly at the edge portion. It is possible to prevent unevenness in film thickness. In other words, by devising the cross-sectional shape of the evaporation mask, it is possible to cause the evaporation particles that are not deposited due to the protrusion of the mask before reaching the evaporation surface to be evaporated on the substrate as the evaporation surface.
[0020]
Furthermore, a resin mask can be made lighter in weight than a mask made of metal, has less slack due to gravity, and can keep the mask stretched. This makes it possible to reduce the wraparound of the deposited film due to the lifting of the deposition mask. As a result, it is possible to form an accurate pattern conforming to a predetermined dimension.
[0021]
Various methods, such as a photolithography technique using a photocurable resin and an injection molding method, can be given as a method for producing the evaporation mask of the present invention. Hereinafter, a photolithography technique using a photocurable resin will be described as an example. However, in the present invention, the shape of an evaporation mask is important, and does not depend on a manufacturing method or a material.
[0022]
A deposition mask made of a photocurable resin, here a positive photoresist as an example, will be described with reference to FIG.
[0023]
First, as shown in FIG. 1A, a photocurable resin 2 is formed on a substrate 1 by using a film forming technique such as spin coating, and a substrate that transmits irradiation light on the photocurable resin 2 is formed. A light-shielding mask 3 having a pattern is mounted thereon to expose the light.
[0024]
Then, as shown in FIG. 1 (b), the portion irradiated with light is cured to form a light-cured portion 4, and the portion not irradiated with light becomes a non-cured portion 5.
[0025]
Thereafter, as shown in FIG. 1C, when the light-shielding mask 3 is peeled off and the non-cured portion 5 is dissolved with an etchant, the photo-cured portion 4 as a cured resin remains on the substrate 1.
[0026]
Then, as shown in FIG. 1 (d), the adhesion portion between the substrate 1 and the photo-cured portion 4 is peeled off or the substrate 1 is dissolved with an etching solution to form the deposition mask (light-cured portion) 4. finish.
[0027]
At this time, not only the resin fiber portion (hereinafter, referred to as "mask line") is created, but also the frame 7 for holding the pitch and the shape of the mask line 6 as shown in FIGS. 2 (a) and 2 (b). It should be created at the same time. This is because, if the frame 7 for fixing the mask line 6 is to be separately formed, the pitch of the mask line 6 must be adjusted one by one and accurately span the opposite sides of the frame 7. . This is because if the frame 7 is created at the same time as the creation of the mask line 6, the frame 7 and the mask line 6 are already integrated and fixed at a predetermined pitch when the frame 7 is peeled off from the substrate 1. This is true for other creation methods. Also, the taper can be easily formed by changing the degree of light collection. In injection molding and the like, it is possible to create a tapered and accurate mask by properly designing the mold. From the viewpoint of forming the frame 7 and the mask line 6 at the same time, it is preferable that the frame 7 and the mask line (resin fiber portion) 6 are formed of the same type of resin material.
[0028]
As shown in FIGS. 3A and 3B, the resin fiber mask thus formed is attached to a metal or some rigid reinforcing frame 8 by pulling the resin fiber mask with a certain degree of strength. , And a highly accurate deposition mask without bending due to gravity can be produced.
[0029]
Next, a description will be given of a resin fiber which is a constituent material of the evaporation mask.
[0030]
Materials used for making the mask for vapor deposition include nylon, polyester, polyethylene, polypropylene, polystyrene, urethane, epoxy, phenol, melamine, urea, silicon, polyimide, acrylic, Various synthetic fibers and natural fibers such as a vinyl-based, allylic-based ABS resin, or a halide thereof can be used, and a single fiber or a double fiber can be used.
[0031]
However, there are restrictions such as thermal expansion, decomposition, and softening due to a rise in temperature during vapor deposition. Any polymer can be used as long as the temperature rise can be suppressed. As a method of suppressing the temperature rise, for example, there is a method of performing evaporation while cooling the mask, and, in addition, in order to cut off the radiant heat of the evaporation source, a plate having a slit that does not transmit the radiant heat is referred to as an evaporation source. A method is also conceivable in which the particles are interposed between the mask and the vapor deposition particles coming out of the slit. That is, it is understood that basically any polymer can be used.
[0032]
Further, since it is necessary to minimize the slack of the mask when producing the mask, it is more advantageous to apply a certain amount of tension to the mask when attaching the mask to the reinforcing plate 8 shown in FIG. However, if a mask having a sufficient strength is formed, for example, if the mask has a sufficiently large thickness, it is not necessary to attach the reinforcing frame 8.
[0033]
It is advantageous in terms of process and cost that it is not necessary to cool the mask or to worry about radiant heat. In addition, it is more advantageous in terms of cost to remove the film attached to the mask and wash it, rather than disposable once, rather than disposable once, so that the tensile strength is 140 kg / cm ² or less. Thermal durability (including thermal deformation) of 70 ° C or higher, epoxy, silicon, allyl, polyester, phenol, polycarbonate, polyacetal, nylon (polyamide) based on chemical resistance, etc. Fluorine-based, polypropylene-based, polyimide-based, urea-based, and melamine-based are selected (see the data of the Plastics Research Handbook Co., Ltd., Industrial Research Institute, p6-p11).
[0034]
It is possible to form a mask with other polymers, and it is also possible to vapor-deposit, but among them, those which are considered to have good performance were selected.
[0035]
Next, a method of manufacturing a monocolor passively driven organic EL panel using the vapor deposition mask of the present invention will be described. However, the vapor deposition mask of the present invention can be used in addition to this.
[0036]
FIG. 5 shows a cross-sectional structure of the organic EL panel according to the present embodiment. An anode 10, an organic material layer 11 containing a luminescent material, and a cathode 12 are sequentially laminated on a substrate 9 made of a transparent substrate. . That is, as shown in FIG. 6, a plurality of anodes (first electrodes) 10 are patterned on a glass substrate 9 in a stripe shape, an organic material layer 11 to be a light emitting layer is entirely deposited, and finally, a deposition mask of the present invention. , A cathode 12 (second electrode) is sequentially deposited so as to be orthogonal to the anode 10 to form a laminated structure of the anode 10, the organic layer 11, and the cathode 12. At this time, each layer is formed and arranged in a matrix with a crossing portion where the anode 10 and the cathode 12 face each other and are orthogonal to each other as one pixel. FIG. 7 shows the positional relationship among the substrate 9 on which the anode 10 and the organic material layer 11 are stacked, the mask 13 for vapor deposition, and the cathode vapor deposition source when the organic EL display device is manufactured so as to be easily understood.
[0037]
Further, the anode 10, the organic material layer 11 containing a luminescent material, and the cathode 12 will be described.
[0038]
The anode needs to be transparent in order to extract light from the organic material layer 11 serving as a light emitting layer, and a metal, an alloy, an electrically conductive compound having a large work function, or a mixture thereof is used as an electrode material. Preferably, gold, ITO, CuI, tin oxide, indium oxide, zinc oxide, chromium, aluminum, silver and the like are used. This anode can be formed by a vapor deposition method or a sputtering method.
[0039]
The organic material layer 11 has, for example, a two-layer structure of a hole transport layer and an organic light emitting layer, but is not limited to this structure. A transport layer, an electron injection layer, and the like may be further formed to form a multilayer structure.
[0040]
The material for forming the hole transport layer is not particularly limited, and a compound conventionally used as a hole transport material, a novel compound, or the like can be used. For example, α-NPD {N, N′-di (α-naphthyl) -N, N′-diphenyl-1,1′-biphenyl-4,4′-diamine}, MTDATA {4-4′-4 ″- Tris (N- (3-methylphenyl) -N-phenylamino) triphenylamine}, TPD {N, N'-diphenyl-N, N'-bis (3-phenyl) -1,1'-biphenyl-biphenyl -4,4'-diamine} and the like.
[0041]
In the organic light emitting layer, anthracene, pyrene, tris (8-quinolinolato) aluminum complex and its derivative, quinolinol, quinoline derivative, bisstylanthracene derivative, coumarin derivative, perinone derivative, tetraphenylbutadiene derivative, oxadiazole derivative, phthalimide derivative , Aldazine derivatives, pyrazirine derivatives, cyclopentadiene derivatives, pyrrolopyridine derivatives, styrylamine derivatives, aldazine derivatives, naphthalimide derivatives, distilbenzene derivatives, thiadiazolopyridine derivatives and the like. In the case of a polymer system, a polyphenylenevinylene derivative, a polyparaphenylene derivative, a polythiophene derivative, or the like can be used.
[0042]
Furthermore, a small amount of impurities may be intentionally mixed into the organic light emitting layer for the purpose of improving the light emitting efficiency or extending the light emitting life. Specifically, it is selected from rubrene, quinacridone derivative, phenoxazone 660, dicyanomethylenestilpyran derivative, perinone, perylene, coumarin derivative, dimethylaminopyrazinecarbonitrile derivative, Nile Red, rhodamine derivative and the like.
[0043]
The formation of the organic material layer 11 is mainly performed by a vacuum evaporation method, but electron beam evaporation, a sputtering method, a molecular lamination method, and coating from a solvent are also possible.
[0044]
The cathode 12 is preferably a metal having a low work function in order to efficiently transfer electrons to the light-emitting layer. Specifically, aluminum, tin, indium, lead, magnesium, silver, copper, molybdenum, nickel, tungsten, a rare earth element alone , Alkali metals or alloys of these metals are used. The cathode 12 is formed by a vapor deposition method or a sputtering method. At this time, the deposition mask according to the present invention is effective for keeping the film thickness uniform within the dot and keeping the dot area constant.
[0045]
【The invention's effect】
As described above, according to the present invention, the vapor deposition mask has a shape that does not rise from the surface to be vapor-deposited, and there is no short circuit between the electrodes because there is no wraparound of the vapor deposition film. A pattern can be formed. Therefore, the electrodes of the organic EL display device can be formed accurately and stably.
[Brief description of the drawings]
FIG. 1 shows a method for producing a deposition mask of the present invention, and (a) to (d) are explanatory diagrams of the production procedure.
FIG. 2 is a view showing a completed product of a deposition mask of the present invention. (A) is a plan view of the finished product. (B) is AB sectional drawing of (a).
FIG. 3 is a diagram showing a reinforcing frame for reinforcing the vapor deposition mask of the present invention. (A) is a top view of a reinforcement frame. (B) is a sectional view of a state in which a resin mask is stuck to the reinforcing frame.
FIG. 4 is an explanatory view showing a cross-sectional shape of the evaporation mask of the present invention. (A) is a vapor deposition mask having a trapezoidal cross section. (B) is a figure which shows the example of another cross section.
FIG. 5 is a cross-sectional view illustrating an example of a layer configuration in the organic EL display device of the present invention.
FIG. 6 is a schematic view showing a pattern shape of an anode in the organic EL display device of the present invention.
FIG. 7 is a schematic diagram showing a positional relationship among a substrate, a deposition mask, and a cathode deposition source when an organic EL display device of the present invention is produced.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 substrate 2 light-cured resin 3 light-shielding mask 4 light-cured part 5 uncured part 6 mask line 7 frame 8 reinforcing frame 9 substrate (transparent substrate)
Reference Signs List 10 anode 11 organic material layer 12 cathode 13 evaporation mask

Claims (7)

On a substrate, at least an anode, an organic material layer containing a luminescent material, and a cathode are laminated, and a plurality of columns of anodes are arranged along one direction, and a plurality of rows of cathodes are arranged along a direction orthogonal to the anode. In an evaporation mask used to form an anode and a cathode of an organic electroluminescence display device,
A frame that partitions the peripheral portion of the mask, comprising a plurality of resin fiber portions that are laid in parallel along one direction between opposing sides of the frame,
A surface of the resin fiber portion, which is in contact with the surface to be vapor-deposited, constitutes a plane portion. The cross-sectional shape of the said resin fiber part WHEREIN: The width | variety of the plane part which contacts the said to-be-deposited surface is formed larger than the width of the surface part opposed to this, The vapor deposition for Claim 1 characterized by the above-mentioned. mask. The cross-sectional shape of the resin fiber portion, wherein a width of a flat portion that contacts the deposition target surface is formed to be larger than a maximum value of a thickness width orthogonal to the deposition target surface. 3. The deposition mask according to 2. The vapor deposition mask according to any one of claims 1 to 3, wherein a cross-sectional shape of the resin fiber portion is a triangle, a square, a rectangle, a trapezoid, a polygon, or a semicircle. 5. The vapor deposition mask according to claim 1, wherein the frame and the resin fiber portion are formed of the same resin material. 6. The mask for vapor deposition according to any one of claims 1 to 5, wherein the frame body is reinforced by a reinforcing frame so as to impart a tension to the resin fiber portion. On a substrate, at least an anode, an organic material layer containing a light-emitting material, and a cathode are laminated, and a plurality of columns of anodes are arranged along one direction, and a plurality of rows are arranged along a direction orthogonal to the anodes. In an organic electroluminescent display device provided with a cathode,
7. An organic electroluminescent display device, wherein an anode and a cathode are pattern-formed on a substrate so as to be orthogonal to each other by using the vapor deposition mask according to claim 1.

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