JP2000173769A - Manufacture of organic electric field light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain highly accurate, stable, and fine patterning under a wide condition range by a masking method by patterning at least one of a light-emitting layer and a second electrode with a shadow mask held with tension applied. SOLUTION: On a first electrode in an organic electric field light-emitting device, a shadow mask, in which at least one of a mask part 31 and a reinforcing line 33 is made of a magnetic material, is brought into tight contact with a spacer which is raised vertically on a substrate to a second electrode by means of magnetic force, so that the substrate and the shadow mask are uniformly brought into mutual contact, and consequently, patterning accuracy can be improved. In this process, the magnetic material constituting one of the mask part 31 and the reinforcing line 33 is selected from a metallic material, a magnetic material, a rare earth magnetic material, a magnetic core material, and a green compact material prepared by compression molding fine powder with a binder, and this material is formed into a sheet shape so as to be formed into the shadow mask. This shadow mask, in which one of the mask part 31 and the reinforcing line 33 is made of a magnetic material, in attracted by a magnet arranged, on the substrate back side in the organic electric field light emitting device to be brought into tight contact with the spacer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic electroluminescent device which can be used in fields such as display devices, flat panel displays, backlights, and interiors.

[0002]

2. Description of the Related Art In recent years, an organic electroluminescent device has attracted attention as a new light emitting device. This element emits light by the recombination of the holes injected from the anode and the electrons injected from the cathode in the organic light emitting layer sandwiched between both electrodes,
It is possible to emit light with high luminance at a low voltage by C.D. W.
Tang et al. (Appl. Phy.
s. Lett. 51 (12) 21, p. 913,198
7).

FIG. 19 is a sectional view showing a typical structure of an organic electroluminescent device. A hole transport layer 5, a light-emitting layer 6, and a second electrode (cathode) 8 are laminated on a transparent first electrode (anode) 2 formed on a glass substrate 1, and light emission generated by driving by a driving source 9 is It is taken out through one electrode and the glass substrate. Such an organic electroluminescent device is thin, can emit high-intensity light under low-voltage driving, and can emit multicolor light by selecting an organic light-emitting material. Application to a light-emitting device such as a display device or a display is actively studied. It is.

In such a case, for example, at least the organic light emitting layer and the second electrode are provided with high precision in a simple matrix type color display as shown in FIGS. A patterning technique is required.

Conventionally, a photolithography method, which is a wet process, is used for such fine patterning. JP-A-6-234969 discloses a technique for obtaining an element to which a photolithography method can be applied by devising an organic material.

As a method of patterning the second electrode without using a wet process, Japanese Patent Application Laid-Open Nos. 5-275172 and 8-315981 disclose a technique of a partition wall method. The technology disclosed in Japanese Patent Application Laid-Open No. 5-275172 is
The partition walls are formed at intervals on the substrate, and the electrode material is vapor-deposited on the substrate obliquely. Japanese Patent Application Laid-Open No. 8-315981 discloses a technique in which a partition having an overhang portion is formed on a substrate, and an electrode material is vapor-deposited on the substrate in an angle range centered in a vertical direction.

The conventional mask method is a general patterning method that does not use a wet process. In this method, a shadow mask is arranged in front of a substrate, and patterning is realized by depositing a deposit through an opening.

As a fine patterning method using a mask method, Japanese Unexamined Patent Application Publication No. 9-115672 discloses a mask technique in which a light emitting layer and a second electrode are patterned using a common shadow mask. In this method, a practical pitch simple matrix type color display is realized by patterning an organic thin film layer and a second electrode for each emission color using a shadow mask having a mask portion wider than an opening width. ing.

[0009]

However, the above-mentioned conventional method has the following problems.

In the above-mentioned photolithography method, the performance of the organic electroluminescent device is remarkably deteriorated because the organic thin film layer constituting the organic electroluminescent device generally has poor durability against moisture, organic solvents and chemicals. In addition, in order to obtain an organic electroluminescent element to which a wet process can be applied, there is a problem that materials to be used are limited.

In the above-mentioned partition method, patterning is realized by utilizing the shadow of the deposit created by the partition.
High-precision patterning cannot be performed under conditions where various deposition angles exist or under conditions where the amount of wrap around of the deposition material is large. For this reason, there are problems with increasing the substrate area, increasing the deposition rate, and increasing the precision of patterning. Further, it has not been easy to stably form a partition having a large sectional aspect ratio or a partition having a special shape having an overhang portion over the entire surface of the substrate. Further, this method is suitably used for patterning the second electrode, but cannot be applied to patterning of the light emitting layer.

In the mask method, since the thin film layer and the second electrode are laminated in the same planar shape, not only a plurality of electrode material deposition steps are required for forming the second electrode, but also the second electrode is formed. However, there is a problem that it can be applied only to a display structure in which is used as a data line. In addition, the shadow mask is provided with an infinite number of very elongated stripe-shaped openings, and means for preventing deformation of the shape, such as providing a reinforcing line, cannot be used. Therefore,
In order to maintain the shape of the opening, it was necessary to use a relatively thick shadow mask, and the cross section of the mask portion had to be tapered so that the shadow mask itself did not form a shadow of vapor deposition. Further, there is a problem that even if an attempt is made to improve the flatness of the shadow mask, only a force can be applied linearly in the longitudinal direction of the stripe-shaped opening.

As described above, although the mask method is a suitable technique having a wide range of applications, there has been a problem in that the opening portion is deformed or the flatness is deteriorated due to insufficient strength of the shadow mask.
In particular, since the shadow mask used becomes thinner as the finer pattern becomes thinner, this problem becomes more serious, and it is difficult to realize the sub-millimeter level fine patterning required for display applications with high accuracy and stability. It was difficult.

It is an object of the present invention to solve the above problem and to provide a method of manufacturing an organic electroluminescent device capable of performing high-precision fine patterning stably under a wide range of conditions by a mask method.

[0015]

These objects are achieved by the present invention described below. The present invention provides an organic electroluminescence including a step of forming a thin film layer including a light emitting layer made of at least an organic compound on a first electrode formed on a substrate, and a step of forming a second electrode on the thin film layer. A method for manufacturing an element, comprising: patterning at least one of the light-emitting layer or the second electrode using a shadow mask held in a tensioned state. is there.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 show an example of an organic electroluminescent device manufactured by the manufacturing method of the present invention. Substrate 1
A first electrode 2 having a stripe shape formed thereon and a light emitting layer 6 made of an organic compound patterned on each first electrode
, And a stripe-shaped second electrode 8 orthogonal to the first electrode are laminated, and a plurality of light emitting regions having an organic electroluminescent element structure are formed at intersections of both electrodes. . Each light-emitting region emits red (R), green (G), and blue (B) light by using different materials for the light-emitting layer. By driving this simple matrix light-emitting device line-sequentially, an image or the like is displayed in color. It is possible to Also,
If necessary, a spacer 4 having a height exceeding the thickness of the thin film layer may be formed on the substrate.

Hereinafter, the present invention will be described with reference to the method for manufacturing an organic electroluminescent device. However, the present invention is not limited to the method for manufacturing an organic electroluminescent device having the exemplified form and structure. The present invention can be applied to an organic electroluminescent device having an arbitrary structure irrespective of a type such as a type, a simple matrix type, an active matrix type, and the number of light emission colors such as color and monochrome.

According to the manufacturing method of the present invention, at least one of the light emitting layer and the second electrode is patterned by using a shadow mask held in a state where tension is applied, and only the light emitting layer is patterned by a mask method. Thus, the second electrode can be patterned by the partition method, or both can be patterned by the mask method. By applying tension to the shadow mask, the flatness of the shadow mask is improved, and the effect of suppressing the size change of the shadow mask due to changes in the surrounding temperature and radiant heat from the evaporation source can be expected. realizable.

The method for applying tension to the shadow mask is not particularly limited. By connecting the end of the shadow mask to a movable means, vapor deposition can be performed while mechanically applying tension from the movable mechanism in a vacuum, or tension can be applied to the shadow mask using gravity or magnetic force. Good. Usually, a sheet-like substance provided with an opening as a shadow mask is used, but, for example, a plurality of linear substances are arranged in a stripe pattern, and a tension is applied to them to have a stripe-shaped opening. It is also possible to have the same function as a sheet-shaped shadow mask. There is no particular limitation on the shape of the opening and the cross section of the shadow mask, so that tension may be applied to the mask by an optimal method for obtaining necessary flatness.

The shadow mask can be fixed to the frame while applying tension to the shadow mask. If the mechanical strength of the frame is sufficient, the shadow mask is always held under tension, so using a shadow mask fixed to the frame has the same effect as applying tension during patterning Is obtained. This method is preferably used in the present invention, because it also facilitates the handling of thin shadow masks.

The fixing method to the frame can be easily achieved by bonding the frame to a shadow mask which is mechanically tensioned. As the bonding means, bonding with a curable resin or a plastic resin, welding using an electron beam or a laser, a method of mechanical caulking, a method of depositing a metal or the like by an electrodeposition method and fixing the same are used. be able to. In such a case, it is also possible to fix the shadow mask to the frame in a heated state, return the temperature to room temperature, and apply tension using thermal expansion. In addition, before being mounted on the frame, the flatness of the shadow mask can be further improved by annealing or the like. The tension applied to the shadow mask is preferably not biased in one direction and is basically isotropic, but is not limited to this depending on the shape of the shadow mask.

Since the dimensions of the shadow mask and the frame are delicately changed by heat, the thermal expansion ratio of the material is preferably small. The required value depends on the conditions of use and the required accuracy, so it is difficult to specify it unconditionally. However, the coefficient of linear expansion near room temperature is preferably 50 × 10 ⁻⁶ K ⁻¹ or less, and 20 × 10 ⁻⁶ K ^{− 1} , more preferably 10 × 10 ⁻⁶ K ⁻¹ or less.

The gap between the substrate and the shadow mask is very important in realizing fine patterning. If the gap is large, a wraparound of the deposit occurs and the pattern accuracy is deteriorated. When the difference between the maximum value and the minimum value of the gap generated between the shadow mask and the substrate during patterning is defined as the flatness of the shadow mask, the flatness is 100 μm.
m, preferably 50 μm or less, more preferably 20 μm or less. When the substrate is planar, it is important to improve the planarity of the shadow mask in order to reduce the flatness of the shadow mask, and the effect of the present invention becomes clear. When the substrate is not planar, it is preferable to make the difference between the gap between the substrate and the shadow mask as small as possible so that the shadow mask is arranged along the substrate and to improve the flatness of the shadow mask. . Also in this case, it is effective to apply tension to the shadow mask.

As for the thickness of the shadow mask, a thicker one is more advantageous in terms of strength, but it is substantially difficult to form a fine opening pattern in the thicker shadow mask as described above. There is also a problem that the part itself becomes a shadow of vapor deposition. In the present invention, for the purpose of fine patterning, the thickness of the shadow mask is preferably 200 μm or less, more preferably 100 μm or less, 80 μm or less, and even more preferably 50 μm or less. Regardless of the thickness, the cross section of the shadow mask may be rectangular or tapered.

Next, the shadow mask used in the present invention will be described with reference to specific examples. FIG. 4 shows an example of a shadow mask for patterning the light emitting layer. An opening 32 having a shape corresponding to each light emitting layer pattern is provided in the mask portion 31, and a reinforcement formed in the same plane as the mask portion so as to cross the opening to prevent deformation of the opening shape. Line 33 is present. Further, the shadow mask is fixed to a frame 34 for easy handling.
The substrate and the shadow mask are aligned so that the center of the first electrode and the center of the opening on the substrate coincide with each other, and the reinforcing line coincides with the gap between the second electrodes formed later. In this state, a light-emitting material is deposited to form a light-emitting layer in a desired region. By repeating this operation three times, each RGB light emitting layer can be patterned on the first electrode.

The light emitting layer may be patterned using a number of shadow masks corresponding to each light emitting layer pattern. However, when the same light emitting layer pattern is repeatedly formed as in a matrix type light emitting device, one light emitting layer is used. Each light emitting layer can be patterned while the positions of the shadow mask and the substrate are relatively shifted. Further, the light emitting layer corresponding to one light emission color may be patterned by two or more evaporation steps.

There is no particular limitation on the structure of the shadow mask, but the reinforcing line should match the gap between the second electrodes or the spacer formed in that region so that there is no shadow of the reinforcing line in the light emitting region. Preferably, a reinforcing line is arranged in the opening.

The width of the reinforcing line is not particularly limited, but is preferably smaller than the portion where no light emitting layer is present, that is, the width of the non-light emitting region in the organic electroluminescent device. Therefore, the reinforcing line width is preferably smaller than 50 μm, and 30 μm
More preferably, it is smaller.

Although the plane size of the opening is not particularly limited, from the viewpoint of reducing the possibility of short-circuit between the first electrode and the second electrode, the opening is larger than the exposed portion of the first electrode corresponding to each light emitting region. That is, it is preferable that the light emitting layer pattern is large. In the simple matrix type light emitting device shown in FIGS. 1 to 3, a value of 100 μm can be exemplified as a typical lateral pitch of each light emitting region at a practical level. In this case, assuming that the width of the first electrode is 70 μm, the width of the light emitting layer pattern and the opening is centered at 100 μm, which is equal to the pitch, so that the width is larger than the width of the first electrode and does not overlap the adjacent first electrode. It is preferable to set the value as follows.

When a monochrome light emitting device is manufactured, patterning of the light emitting layer can be omitted. In this case, a light-emitting material may be deposited over the entire region where the light-emitting region exists to form a light-emitting layer.

FIGS. 5 and 6 show an example of the shadow mask for patterning the second electrode. An opening 32 having a shape corresponding to the second electrode pattern is provided in the mask portion 31, and there is a reinforcing line 33 formed across the opening to prevent deformation of the opening shape. Also,
A gap 36 is provided between one surface 35 of the mask portion and the reinforcing line.
Exists. Further, the shadow mask is fixed to a frame 34 for easy handling. The surface of the shadow mask where the reinforcing line does not exist is directed toward the substrate, and the mask and the spacer formed on the substrate are aligned with each other. A second electrode is formed in a desired region by depositing a material. The second electrode material that has flown from the reinforcing wire 33 side is deposited around the shadowed portion of the reinforcing wire due to the presence of the gap 36, so that the second electrode is not divided by the reinforcing wire. .

The conditions for vapor deposition of the second electrode material are not particularly limited, and vapor deposition may be performed from a single vapor deposition source. In contrast, it is effective to deposit the second electrode material around the reinforcing wire from a plurality of different directions. As a method for achieving such an effect, when using a high vacuum process such as a vacuum deposition method in which a deposition material reaches a substrate straight from a deposition source, a second electrode material is deposited from a plurality of deposition sources. A method in which the second electrode material is deposited while moving or rotating the substrate relative to one or more deposition sources is preferable in terms of process.
In addition, low vacuum processes such as sputtering deposition method,
This is a preferable method because, in principle, the second electrode material flies from a random direction and wraps around the reinforcing line to be easily deposited.

As another example of the shadow mask for patterning the second electrode, for example, the reinforcing lines may be in a mesh shape, or the mask portion 31 may have a tapered shape as shown in the sectional view of FIG. The structure may be such that the reinforcing wire 33 is integrated with the mask portion 31 as shown in the sectional view of FIG. Also, as shown in FIG.
By using a shadow mask in which 3 and the mask portion 31 are formed in the same plane, the second electrode material is wrapped around the gap formed between the substrate and the reinforcing wire by the spacer formed on the substrate, It is also possible to pattern the second electrode.

The reinforcement line width is preferably equal to or less than the height of the gap, because basically, the thinner the line, the larger the amount of wraparound of the deposit. Further, the number of reinforcing lines is preferably as small as possible within a range where deformation of the opening can be sufficiently prevented in order to reduce a shadowed portion of the reinforcing lines.

As described above, the method of patterning the second electrode in one vapor deposition step is preferable, but the number of steps is not particularly limited, and a plurality of shadow masks may be used, or one shadow mask and a substrate may be used. The second electrode may be patterned in a plurality of vapor deposition steps, for example, by relatively shifting the position of the second electrode.

The materials constituting the shadow mask for the light emitting layer or the second electrode include stainless steel, copper alloy,
Preferred examples include metal materials such as nickel alloys and aluminum alloys, known resin materials, and photosensitive resin materials obtained by imparting photosensitivity to polymers such as polyvinyl-based, polyimide-based, polystyrene-based, acrylic-based, novolak-based, and silicone-based polymers. Although it can be mentioned, it is not particularly limited. The material forming the mask portion of the shadow mask and the reinforcing line may be the same or different. In addition, by forming a relatively flexible cushion portion using the above-mentioned resin material on the surface of the shadow mask that is in close contact with the substrate, damage to the thin film layer formed on the substrate when both are in close contact with each other Can also be reduced.

In the manufacturing method of the present invention, it is preferable that a shadow mask in which at least one of the mask portion and the reinforcing wire is made of a magnetic material is brought into close contact with the spacer by magnetic force. By doing so, the substrate and the shadow mask can be more evenly and surely brought into close contact, so that the patterning accuracy can be further improved. The method of fixing the relative position between the substrate and the shadow mask after alignment and the method of supporting the weight of the shadow mask itself are not particularly limited, and a magnetic force may be used, or a mechanical method may be used. It is also possible to use.

The magnetic material constituting at least one of the mask portion and the reinforcing wire includes metal materials such as iron alloy, cobalt alloy and nickel alloy, carbon steel, tungsten steel, and the like.
Chrome steel, cobalt steel, KS steel, MK steel, Alnico
Steel, NKS steel, Cunico steel, OP ferrite, Ba
Magnetic materials such as ferrite, Sm-Co and Nd-Fe
-B based rare earth magnet material, silicon steel sheet, Al-Fe
Preferred are alloys, magnetic core materials such as Mn-Zn-based ferrites, Ni-Zn-based ferrites, and Cu-Zn-based ferrites, and compacted materials obtained by compression-molding a fine powder such as carbonyl iron, Mo permalloy, and sendust together with a binder. Examples can be given. It is preferable to produce a shadow mask from a sheet formed from these magnetic materials, but it is also possible to produce a shadow mask from a sheet formed by mixing powder of the magnetic material with rubber or resin. is there. If necessary, a shadow mask may be formed from a magnetic material that has been magnetized from the beginning, or a shadow mask may be formed and then magnetized.

As a method of bringing the shadow mask into close contact with the spacer by magnetic force, the shadow mask in which at least one of the mask portion and the reinforcing wire is made of a magnetic material is attracted by a magnet arranged on the back side of the substrate of the organic electroluminescent device. Is preferred. However, the above method is not particularly limited since a magnetic force may be exerted between the shadow mask and one or more other objects. For example, a shadow mask functioning as a magnet and a substrate made of a magnetic material may be used. It is also possible to improve the adhesiveness by applying a suction force between the two by the combination of.

Known permanent magnets and electromagnets can be used as the magnet. The shape and size are not particularly limited. Further, the shadow mask may be suctioned using a single magnet, but it is also possible to use a magnet assembly formed by bonding a plurality of magnets or arranging them at predetermined intervals. The distance between the magnet and the shadow mask and the magnitude of the magnetic force acting between them are not particularly limited as long as a sufficient magnetic force can reach the shadow mask.

The method of manufacturing the shadow mask is not particularly limited, and a method such as a mechanical polishing method, a sand blast method, a sintering method, or a laser processing method can be used. It is preferable to use a method, an electroforming method, or a photolithography method.

In the production of the shadow mask, the mask portion and the reinforcing line may be formed in a single step. However, the mask portion and the reinforcing line are separately formed, and then the two are overlapped and connected. A shadow mask can also be made. In this case, the two may be connected by a method such as adhesion, pressure bonding, or welding, or when at least one of the two has conductivity, the two may be connected using the electrodeposition phenomenon. That is, the mask portion and the reinforcing wire are immersed in an electrolytic solution in close contact with each other, and the two are connected by depositing an electrodeposit on the contact portion between the two by energization. Generally, a metal material such as nickel is selected for the electrodeposit, but an organic material such as polyaniline can also be used. Alternatively, a shadow mask can be formed by forming a photosensitive resin layer on the previously formed mask portion and patterning the photosensitive resin layer by a photolithography method.

As described above, it is preferable that the reinforcing line width is basically small, but it becomes difficult to handle the shadow mask during the manufacturing process. Therefore, it is also possible to first produce a shadow mask having a relatively large reinforcing line or mask portion, fix it to the frame while applying tension thereto, and then reduce the reinforcing line to a desired line width. Although thinning by etching is easy in the process, the thinning method is not particularly limited, and an appropriate method may be used depending on the material constituting the shadow mask.

As a material for forming the frame, a low-expansion alloy such as 42 alloy, various ceramics, various glass materials, and the like can be used together with the shadow mask material exemplified above.

In the manufacturing method of the present invention, it is possible to form a spacer having a height at least partially exceeding the thickness of the thin film layer on the substrate. For example, as shown in FIG. 3, the spacer 4 is formed on the substrate 1 so as to have a height exceeding the thickness of the thin film layer 10. The shadow mask adheres to the spacer when patterning the light emitting layer or the second electrode, so that it is possible to prevent the thin film layer formed on the substrate before that from being damaged. There is no particular limitation on the height of the spacer, but in consideration of the deterioration of pattern accuracy caused by the deposition material wrapping around the gap formed between the shadow mask and the substrate by the spacer,
0.1 to 100 μm, preferably 1 to 10 μm
Formed in the range.

The position where the spacer is formed is not particularly limited, but it is preferable to arrange the spacer around the non-light emitting region in the organic electroluminescent device so as to minimize the loss of the light emitting area. The structure of the spacer is not particularly limited, and may be formed by one layer or by laminating a plurality of layers. The first spacer is formed so as to cover the end of the first electrode to add a function as an interlayer insulating layer, or the first spacer is formed in a matrix, and the second spacer is overlapped with a part thereof to form a second spacer. It is also possible to form a spacer. Also, a plurality of dot-shaped spacers can be arranged on the substrate, and the planar shape can be any shape such as a circle or a polygon. The cross-sectional shape of the spacer is not particularly limited, and may be a taper type or a reverse taper type.

Since the spacer is often formed in contact with the first electrode, it is preferable that the spacer has sufficient electric insulation. A conductive spacer can be used, but in that case, an electrically insulating portion for preventing a short circuit between the electrodes may be formed. As the spacer material, a known material can be used. For an inorganic material, an oxide material such as silicon oxide, a glass material, a ceramic material, and the like, and for an organic material, a polyvinyl, polyimide, polystyrene, acrylic, and novolak are used. Preferred examples include polymer-based resin materials such as silicone-based and silicone-based resins. Further, by blackening the entire spacer or a portion in contact with the substrate or the first electrode, a function like a black matrix that contributes to an improvement in display contrast of the organic electroluminescent device can be added to the spacer. In such a case, as a spacer material, an inorganic substance such as silicon, gallium arsenide, manganese dioxide, titanium oxide or a laminated film of chromium oxide and metal chromium, and an organic substance to the above-described resin material, and a surface layer for enhancing electrical insulation. Known pigments and dyes such as treated carbon black, phthalocyanine, anthraquinone, monoazo, disazo, metal complex salt type monoazo, triallylmethane, aniline, etc., or mixed with the above inorganic material powder Materials can be mentioned as preferred examples.

As a method of forming the spacer layer, when an inorganic material is used, a dry process such as resistance heating evaporation, electron beam evaporation, or sputtering is used. When an organic material is used, spin coating or slitting is used. Examples thereof include a method using a wet process such as a die coating method and a dip coating method, but are not particularly limited.

The method of patterning the spacer is not particularly limited, but a method of forming a spacer layer on the entire surface of the substrate after the first electrode patterning step and patterning the spacer layer by a known photolithography method is easy in process. The spacer may be patterned by an etching method using a photoresist or a lift-off method, or by patterning by directly exposing and developing a spacer layer using a photosensitive spacer material obtained by adding photosensitivity to the above-described resin material. You can also.

The first and second electrodes only need to have a conductivity capable of supplying a current sufficient for light emission of the organic electroluminescent element.
Preferably, at least one of the electrodes is transparent to extract light.

The use of a transparent electrode is not a major obstacle if the visible light transmittance is 30% or more, but ideally 100%.
Is preferably closer to Basically, it is preferable to have the same transmittance in the entire visible light range. However, when it is desired to change the emission color, it is possible to positively impart light absorbency. In such a case, it is technically easy to change the color using a color filter or an interference filter. Transparent electrode materials include indium, tin, gold,
It is often composed of at least one element selected from silver, zinc, aluminum, chromium, nickel, oxygen, nitrogen, hydrogen, argon, carbon, but inorganic conductive substances such as copper iodide and copper sulfide, polythiophene, polypyrrole It is also possible to use a conductive polymer such as polyaniline or the like, and there is no particular limitation.

Preferred examples of the first electrode material include tin oxide, zinc oxide, indium oxide, vanadium oxide, and indium tin oxide (ITO) formed on a transparent substrate. In display applications where patterning is performed, it is particularly preferable to use ITO having excellent workability for the first electrode. ITO may contain a small amount of metal such as silver or gold to improve conductivity, and use tin, gold, silver, zinc, indium, aluminum, chromium, and nickel as ITO guide electrodes. It is also possible. In particular, chromium is a preferred guide electrode material because it can have both functions of a black matrix and a guide electrode. From the viewpoint of power consumption of the organic electroluminescent device, the resistance of ITO is preferably low. An ITO substrate having a resistance of 300 Ω / □ or less functions as the first electrode. However, it is now easy to supply an ITO substrate having a resistance of about 10 Ω / □, so that a low resistance product can be used. The thickness of the ITO can be arbitrarily selected according to the resistance value, but usually the thickness is 100 to 300 nm.
Is often used. The material of the transparent substrate is not particularly limited, and a plastic plate or film made of polyacrylate, polycarbonate, polyester, polyimide, or aramid can be used. A preferred example is a glass plate. As for the material of the glass, soda lime glass or the like provided with a barrier coat such as non-alkali glass or silicon oxide film can be used. In addition, the thickness is 0.5 mm because it is sufficient to maintain the mechanical strength.
That's enough. The method for forming ITO is not particularly limited, such as electron beam evaporation, sputtering evaporation, and a chemical reaction method.

The method of patterning the first electrode is not particularly limited as long as a known technique can be used. Therefore,
Although the first electrode may be formed on the substrate by a patterning method using a shadow mask having a reinforcing line of the present invention, generally, the first electrode formed on the entire surface of the substrate is etched by a photolithographic method. It can be patterned. The pattern shape of the first electrode is not particularly limited, and an optimum pattern may be selected according to the application. The first electrode may be patterned as needed. For example, when the first electrode is a common electrode in a segment type light emitting device, the first electrode may be used without patterning.

Although the material of the second electrode is not particularly limited, when ITO is used as the first electrode, since the ITO generally functions as an anode, electrons are efficiently applied to the organic electroluminescent device by the second electrode. It is required to function as a cathode that can be injected well. Therefore, it is possible to use a low work function metal such as an alkali metal as the second electrode material, but considering the stability of the electrode, platinum, gold, silver,
It is preferable to use metals such as copper, iron, tin, aluminum, magnesium and indium, or alloys of these metals with low work function metals. In addition, a small amount of a low work function metal is previously doped into the thin film layer of the organic electroluminescent element, or a thin layer of a metal salt such as lithium fluoride is formed on the thin film layer, and then a relatively stable metal is applied to the second electrode. By forming as, a stable electrode can be obtained while keeping the electron injection efficiency high. The formation method of the second electrode is also resistance heating evaporation, electron beam evaporation, sputtering evaporation,
There is no particular limitation as long as it is a dry process such as an ion plating method.

The thin film layers included in the organic electroluminescent device include 1) a hole transport layer / light emitting layer, 2) a hole transport layer / light emitting layer / electron transport layer, 3) a light emitting layer / electron transport layer, and 4)
Any of the above-described light-emitting layers in which the layer constituent materials are mixed together may be used. That is, if a light emitting layer made of an organic compound exists as a device configuration, the above-mentioned 1) to 3)
In addition to the multi-layer structure, the light emitting material alone or a single light emitting layer containing the light emitting material and the hole transporting material or the electron transporting material as in 4) may be provided.

The hole transporting layer is formed of a hole transporting material alone or a hole transporting material and a polymer binder. As a hole transport material, N, N′-diphenyl-N, N′-di (3-methylphenyl) -1,1 ′ is used for a low molecular weight compound.
-Diphenyl-4,4'-diamine (TPD), N,
N'-diphenyl-N, N'-dinaphthyl-1,1'-
Heterocycles such as triphenylamines represented by diphenyl-4,4'-diamine (NPD), N-isopropylcarbazole, pyrazoline derivatives, stilbene compounds, hydrazone compounds, oxadiazole derivatives and phthalocyanine derivatives Preferred examples include compounds, and in the case of polymers, polycarbonates having a low molecular weight compound in the side chain, styrene derivatives, polyvinyl carbazole, polysilane, and the like.

In the application of the simple matrix type light emitting device, the light emitting time of each organic electroluminescent element is short, and it is necessary to instantaneously emit light with high luminance by passing a pulse current. In such a case, the hole transporting material is required to have not only excellent hole transporting properties and stable thin film forming ability, but also good electron blocking properties to prevent a decrease in luminous efficiency due to leakage of electrons in the hole transporting layer. Is done. In order to satisfy the above characteristics in a well-balanced manner, the production method of the present invention particularly preferably includes a step of forming an organic layer made of an organic compound having a biscarbazolyl skeleton.

Examples of the light emitting material include anthracene derivatives, pyrene derivatives, 8-hydroxyquinoline aluminum derivatives, bisstyrylanthracene derivatives, tetraphenylbutadiene derivatives, coumarin derivatives, and oxadiazoles, which have been known as light emitters for low molecular weight compounds. Derivatives, distyrylbenzene derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, oxadiazole derivatives, thiadiazolopyridine derivatives, etc., in the case of polymer systems, polyphenylenevinylene derivatives,
Preferred examples include polyparaphenylene derivatives and polythiophene derivatives. Preferred examples of the dopant for doping the light-emitting layer include rubrene, quinacridone derivatives, phenoxazone derivatives, DCM, perinone derivatives, perylene derivatives, coumarin derivatives, and diazaindacene derivatives.

Since the electron transporting material is required to efficiently transport the electrons injected from the cathode, it is preferable that the electron transporting material has a large electron affinity, a large electron mobility, and a stable thin film forming ability. As materials satisfying such characteristics, 8-hydroxyquinoline aluminum derivatives, hydroxybenzoquinoline beryllium derivatives, 2- (4-
Biphenyl) -5- (4-t-butylphenyl) -1,
3,4-oxadiazole (t-BuPBD), 1,3
-Bis (4-t-butylphenyl-1,3,4-oxadizolyl) biphenylene (OXD-1), 1,3-bis (4-t-butylphenyl-1,3,4-oxadizolyl) phenylene (OXD- Oxadiazole derivatives, triazole derivatives, phenanthroline derivatives and the like such as 7) can be mentioned as preferred examples.

The materials used for the above-described hole transporting layer, light emitting layer and electron transporting layer can be used alone to form each layer. As the polymer binder, polyvinyl chloride, polycarbonate, polystyrene, poly (N- Vinyl carbazole), polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide,
Solvent-soluble resins such as ethyl cellulose, vinyl acetate, ABS resin, polyurethane resin, phenolic resin, xylene resin, petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin,
It can be used by being dispersed in a curable resin such as a silicone resin.

The method for forming the above-mentioned hole transporting layer, light emitting layer, electron transporting layer, etc. is not particularly limited, such as resistance heating evaporation, electron beam evaporation, and sputtering evaporation. Is preferred in terms of characteristics. The thickness of the organic layer cannot be limited because it is related to its resistance value, but is practically selected from the range of 10 to 1000 nm.

It is also possible to use an inorganic material for the whole or a part of the hole transport layer or the electron transport layer. Preferred examples include silicon carbide, gallium nitride, zinc selenide, and zinc sulfide-based inorganic semiconductor materials.

If necessary, after the second electrode patterning step, the formation of the protective layer and the sealing of the light emitting region can be performed by using a known technique or the patterning technique in the manufacturing method of the present invention.

[0064]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
The present invention is not limited to these examples.

Example 1 A shadow mask having a structure in which a mask portion and a reinforcing line were formed on the same plane as shown in FIG. 4 was prepared for light emitting layer patterning. The outline of the shadow mask is 120
× 84 mm, the thickness of the mask portion 31 is 25 μm,
Stripe-shaped opening 32 having a length of 64 mm and a width of 100 μm
Are arranged at a pitch of 300 μm in the horizontal direction. Each stripe-shaped opening has a width 2 orthogonal to the opening.
Reinforcing lines 33 of 0 μm are formed every 1.8 mm. The shadow mask is fixed to a stainless steel frame 34 having the same outer shape and a width of 5 mm.

A method for manufacturing this shadow mask will be described below. First, Ni-
By depositing a Co alloy, a sheet having a mesh-shaped blank portion 38 connected around the mask portion 31 as shown in FIG. 10 was formed. Next, the mask portion and the frame were overlapped while applying tension to the sheet using the mesh blank portion, and both were fixed using an adhesive. Finally, a mesh-shaped blank portion protruding from the frame was cut out to obtain a light-emitting layer shadow mask.

As shown in FIGS. 11 and 12, one surface 35 of the mask portion 31 is used for patterning the second electrode.
A shadow mask having a structure in which a gap 36 is present between the shadow mask and the reinforcing wire 33 was prepared. The outline of the shadow mask is 120 ×
84 mm, the thickness of the mask portion is 100 μm, and 200 stripe-shaped openings 32 having a length of 100 mm and a width of 245 μm are arranged in a horizontal direction at a pitch of 300 μm.
On the mask portion, a mesh-like reinforcing line having a regular hexagonal structure having a width of 40 μm, a thickness of 35 μm, and a distance between two opposing sides of 200 μm is formed. The height of the gap is equal to the thickness of the mask portion and is 100 μm. The shadow mask is fixed to a stainless steel frame 34 having the same outer shape and a width of 5 mm.

A method of manufacturing the shadow mask will be described below with reference to FIG. First, mesh-shaped reinforcing wires were formed in advance by depositing Ni on an electroformed matrix by an electroforming method. First, (a) on an electroformed mold 21 having a pattern of a photoresist 20,
(B) Mask part 3 by depositing Ni-Co alloy
Thereafter, only (c) the photoresist was removed. Next, (d) the reinforcing wire 33 was superposed on the mask portion while applying a tension 22 to the reinforcing wire 33, and the two were connected by depositing Ni in a contact portion between the two by an electrodeposition phenomenon. further,
(E) The mask portion and the reinforcing wire connected while maintaining the tension were removed, and (f) the mask portion and the frame 34 were overlapped, and both were fixed using an adhesive. Finally, the reinforcing line protruding from the frame was cut off to obtain a second electrode shadow mask.

The first electrode was patterned as follows. An ITO glass substrate (manufactured by Geomatic) having a 130-nm-thick ITO transparent electrode formed on a 1.1-mm-thick non-alkali glass substrate surface by sputtering deposition was cut into a size of 120 × 100 mm. ITO
A photoresist was applied on the substrate, and the photoresist was patterned by exposure and development by a normal photolithography method. By removing the photoresist after etching the unnecessary portions of ITO, ITO can be 90 mm long,
It was patterned into a stripe shape having a width of 70 μm. This stripe-shaped first electrode has a pitch of 100 μm in the horizontal direction.
Sixteen are arranged.

The spacer was formed as follows. Polyimide photosensitive coating agent (UR-3, manufactured by Toray Industries, Inc.)
100) was applied onto the ITO substrate by spin coating, and 80
Prebaked at 1 ° C. for 1 hour. Further, the coating film was exposed to ultraviolet light through a photomask to light cure a desired portion, and developed using a developer (DV-505, manufactured by Toray Industries, Inc.). Finally, apply the patterned coating film in a clean oven at 180 ° C. for 30 minutes,
Baking was performed at 30 ° C. for 30 minutes to form a spacer 4 orthogonal to the first electrode as shown in FIGS. The translucent spacers have a length of 100 mm, a width of 60 μm, and a height of 4 μm, and are arranged 201 at a pitch of 300 μm in the horizontal direction. Further, this spacer had good electric insulation.

After washing the ITO substrate on which the spacer was formed, it was set in a vacuum evaporation machine. In addition, the three shadow masks for the light emitting layer, the shadow mask 1 for the second electrode,
The sheets were set in a vacuum evaporation machine. In the present vacuum evaporation machine, the above four types of shadow masks can be exchanged so that each can be aligned with the substrate in a vacuum with an accuracy of about 10 μm.

The thin film layer was formed as follows by a vacuum evaporation method using a resistance wire heating method. The degree of vacuum at the time of vapor deposition was 2 × 10 ⁻⁴ Pa or less, and the substrate was rotated with respect to the vapor deposition source during vapor deposition.

First, in the arrangement as shown in FIG. 14, copper phthalocyanine is deposited to a thickness of 30 nm and bis (N-ethylcarbazole) is deposited to a thickness of 120 nm on the whole surface of the substrate by a crystal oscillator type film thickness monitor display value. 5 was formed.

Next, a first light-emitting layer shadow mask was arranged at the front of the substrate so that they were in close contact with each other, and a ferrite plate magnet (YBM-1B, manufactured by Hitachi Metals, Ltd.) was arranged at the rear of the substrate. At this time, as shown in FIGS. 15 and 16, the stripe-shaped first electrode 2 is located at the center of the stripe-shaped opening 32 of the shadow mask, the reinforcing line 33 matches the position of the spacer 4, and the reinforcing line is formed. Both are aligned so that the and the spacers are in contact. In this state, 0.3
wt% of 1,3,5,7,8-pentamethyl-4,4-
43 nm of Alq ₃ doped with difluoro-4-bora 3a, 4a-diaza-s-indacene (PM546)
The G light emitting layer was patterned by vapor deposition. Next, the G
Using a second light-emitting layer shadow mask in the same manner as the patterning of the light-emitting layer, 1 wt% of 4- (dicyanomethylene) -2-methyl-6- (julolidylstyryl) -pyran (DCJT) was doped. Alq ₃ at 30 nm
The R light emitting layer was patterned by vapor deposition. Further, similarly, using the third light emitting layer shadow mask, the DPV
Bi was deposited to a thickness of 40 nm to pattern the B light emitting layer. Each of the light emitting layers is disposed every third stripe-shaped first electrode 2 and completely covers the exposed portion of the first electrode. Each of the light emitting layers has a flatness of the shadow mask of 2
Patterning was performed under the condition of 0 μm or less.

Further, in the arrangement shown in FIG. 17, an electron transport layer 7 was formed by evaporating DPVBi to 70 nm and Alq ₃ to 20 nm on the entire surface of the substrate. After that, the thin film layer 10 was exposed to lithium vapor for doping (0.5 nm in equivalent film thickness).

The second electrode was formed as follows by a vacuum deposition method using a resistance wire heating method. The degree of vacuum at the time of vapor deposition was 3 × 10 ⁻⁴ Pa or less, and the substrate was rotated with respect to two vapor deposition sources during vapor deposition.

In the same manner as in the patterning of the light emitting layer, a shadow mask for the second electrode was arranged in front of the substrate so that they were in close contact with each other, and a magnet was arranged behind the substrate. At this time, the two are aligned so that the spacer 4 matches the position of the mask portion 31. In this state, as shown in FIG. 18, aluminum was evaporated to a thickness of 400 nm to pattern the second electrode 8. This second electrode was also patterned under the condition that the flatness of the shadow mask was 20 μm or less.

Finally, in the arrangement shown in FIG. 17, silicon monoxide was deposited on the entire surface of the substrate by a 200 nm electron beam evaporation method to form a protective layer.

As described above, as schematically shown in FIGS. 1 to 3, the width is 70 μm, the pitch is 100 μm, and the number is 816.
A thin film layer 10 including a patterned RGB light emitting layer 6 is formed on the ITO striped first electrode 2, and has a width of 240 μm and a pitch of 30 μm orthogonal to the first electrode.
A simple matrix type color light emitting device in which 200 0 μm striped second electrodes 8 were arranged was produced. Since the three light emitting regions of RGB form one pixel, the present light emitting device has 272 × 200 pixels at a pitch of 300 μm.

Each of the stripe-shaped second electrodes had a sufficiently low electrical resistance over the length of 100 mm without being separated by the reinforcing lines of the shadow mask. On the other hand, there was no short circuit between the second electrodes adjacent in the width direction, and the electrodes were completely insulated.

The light emitting area of this light emitting device is 70 × 240 μm
, And emitted light uniformly in RGB independent colors.
In addition, no decrease in emission color purity in the light emitting region due to the wraparound of the light emitting material during patterning of the light emitting layer was observed, and it was confirmed that high-precision fine patterning was achieved.

When the light-emitting device was driven line-sequentially by a line-sequential driving circuit, clear pattern display and multi-color display were possible.

Comparative Example 1 A simple matrix type color light emitting device was manufactured in the same manner as in Example 1 except that a light emitting layer shadow mask manufactured by fixing to a frame without applying tension was used. The flatness during patterning of the light emitting layer was larger than 100 μm.

The light-emitting region of the light-emitting device emitted light with a size of 70 × 240 μm. However, since a shadow mask having poor planarity was used, a light-emitting material wrapped around during the patterning of the light-emitting layer. RGB was in a mixed state. In addition, uneven brightness of light emission between the light emitting regions due to uneven thickness of the light emitting layer was also observed.

When the light emitting device was driven line-sequentially, pattern display was possible, but multi-color display was unclear.

Example 2 The procedure was the same as in Example 1 until the formation of the electron transport layer. In the formation of the second electrode, is formed orthogonal to the first electrode,
Patterning was performed by using 201 spacers having a pitch of 300 μm as barriers in the barrier rib method, and evaporating aluminum in a region where the barriers exist.

Each of the striped second electrodes had a sufficiently low resistance electrically over the length direction of 100 mm, and there was no short circuit between the second electrodes adjacent in the width direction.

The light emitting area of this light emitting device is 70 × 240 μm
, And emitted light uniformly in RGB independent colors.
In addition, no decrease in emission color purity in the light emitting region due to the wraparound of the light emitting material during patterning of the light emitting layer was observed, and it was confirmed that high-precision fine patterning was achieved.

When the light emitting device was driven line-sequentially by a line-sequential driving circuit, clear pattern display and multi-color display were possible.

[0090]

According to the manufacturing method of the present invention, fine patterning of the light emitting layer and the second electrode can be realized with high precision, since tension is applied to the shadow mask to perform patterning while maintaining the flatness of the shadow mask. Therefore, a decrease in color purity of the light emitting region due to color mixing or the like and a short circuit between the second electrodes hardly occur, and a fine pitch display can be stably manufactured. Furthermore, since the present manufacturing method can be applied to patterning of an arbitrary shape, the structure of the organic electroluminescent device to be manufactured is not limited.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an organic electroluminescent device manufactured according to the present invention.

FIG. 2 is a sectional view taken along the line XX ′ of FIG. 1;

FIG. 3 is a sectional view taken along line YY 'of FIG.

FIG. 4 is a plan view showing an example of a shadow mask for patterning a light emitting layer.

FIG. 5 is a plan view showing an example of a shadow mask for patterning a second electrode.

FIG. 6 is a sectional view taken along the line XX ′ of FIG. 5;

FIG. 7 is a ZZ ′ cross-sectional view showing another example of a shadow mask for patterning a second electrode.

FIG. 8 is a ZZ ′ cross-sectional view showing another example of a shadow mask for patterning a second electrode.

FIG. 9 is a plan view showing another example of the shadow mask for patterning the second electrode.

FIG. 10 is a plan view illustrating a method for manufacturing a shadow mask for patterning a light emitting layer.

FIG. 11 is a plan view showing another example of a shadow mask for patterning a second electrode.

FIG. 12 is a sectional view taken along the line XX ′ of FIG. 11;

FIG. 13 is a cross-sectional view illustrating a method for manufacturing a shadow mask for patterning a second electrode.

FIG. 14 is an XX ′ cross-sectional view illustrating a method for forming a hole transport layer.

FIG. 15 is a sectional view taken along the line XX ′ for explaining a light emitting layer patterning method.

16 is a YY ′ cross-sectional view (side view of FIG. 15) illustrating a light-emitting layer patterning method.

FIG. 17 is a cross-sectional view along the line XX 'illustrating a method for forming the electron transport layer.

FIG. 18 is a cross-sectional view XX ′ illustrating a second electrode patterning method.
Sectional view.

FIG. 19 is a cross-sectional view illustrating an example of a conventional organic electroluminescent device.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 first electrode 4 spacer 5 hole transport layer 6 light emitting layer 7 electron transport layer 8 second electrode 9 driving source 10 thin film layer 11 hole transport material 12 light emitting material 13 electron transport material 14 second electrode material 20 photoresist DESCRIPTION OF SYMBOLS 21 Electroforming mold 22 Tension 31 Mask part 32 Opening 33 Reinforcement line 34 Frame 35 One surface of mask part 36 Gap 38 Mesh blank part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K007 AB00 AB04 AB05 BA06 BB06 CA01 CA05 CA06 CB01 DA00 DB03 EB00 FA00 FA01 FA03 5C094 AA05 BA27 EA05 EB02 FB01 GB10 5C096 AA00 BA01 CC07 EA06 EB00 EB02 EB13

Claims (7)

[Claims] An organic electric field including a step of forming a thin film layer including a light emitting layer made of at least an organic compound on a first electrode formed on a substrate, and a step of forming a second electrode on the thin film layer. A method for manufacturing a light-emitting element, wherein at least one of the light-emitting layer or the second electrode is patterned using a shadow mask held in a tensioned state. . 2. The method according to claim 1, wherein the flatness of the shadow mask at the time of patterning is 100 μm or less.
A method for producing the organic electroluminescent device according to the above. 3. The method according to claim 1, wherein a shadow mask having a thickness of 200 μm or less is used. 4. The method for manufacturing an organic electroluminescent device according to claim 1, wherein a shadow mask having a reinforcing line formed so as to cross the opening is used. 5. The method according to claim 1, wherein a shadow mask made of a magnetic material is adhered to the substrate by magnetic force. 6. The method for manufacturing an organic electroluminescent device according to claim 1, wherein a spacer having a height at least partially exceeding the thickness of the thin film layer is formed on the substrate. 7. A shadow mask fixed to a frame under tension is used.
A method for producing the organic electroluminescent device according to the above.