Manufacture of organic electroluminescent

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a method for manufacturing an organic electroluminescent element capable of converting electrical energy into light, which can be used in fields such as display elements, flat panel displays, backlights, lighting, interiors, signs, signs, and electrophotographic machines.

【0002】

[Conventional technology]

In recent years, active research has been conducted on organic electroluminescent devices in which electrons injected from a cathode and holes injected from an anode recombine in an organic phosphor sandwiched between both electrodes to emit light. .. This device is attracting attention because it is thin, emits high-intensity light under a low driving voltage, and emits light in multiple colors by selecting a fluorescent material.

【0003】

It was first shown by Kodak's CWTang et al. That organic electroluminescent devices emit high brightness (Appl. Phys. Lett. 51 (12) 21, p. 913, 1987). A typical configuration of an organic electroluminescent device presented by Kodak is a hole-transporting diamine compound, 8-hydroxyquinolin aluminum as a light emitting layer, and Mg: Ag as a cathode on an ITO glass substrate by a vapor deposition method. It is installed sequentially, and 1000 cd / m with a drive voltage of about 10 V.²It was possible to emit green light. Some of the current organic electroluminescent devices have different configurations such as those provided with an electron transport layer in addition to the above-mentioned element components, but basically follow the configuration of Kodak. The use of these organic electroluminescent devices capable of high-luminance and multicolor light emission as display devices and the like is being actively studied.

【0004】

However, as pointed out in Nikkei Electronics 1996.1.29 (No.654) p.102, device pattern processing has become one of the major problems.

【0005】

For example, in the case of a full-color display, it is necessary to form R, G, and B light emitting layers at predetermined positions. Usually, such pattern processing is achieved by a wet process represented by a photolithography method, but the organic film forming the organic electroluminescent device has poor durability against moisture, an organic solvent, and a chemical solution. As represented by JP-A-6-234969, it has been shown that an element capable of a wet process can be obtained by devising an organic material, but the organic material used for the element is limited by such a method. Will be done.

【0006】

Further, electrode pattern processing is indispensable for the display element. Even when the electrodes on the upper part of the organic layer are patterned by a wet process, damage to the organic film is still a problem.

【0007】

For this reason, conventionally, organic electroluminescent devices are often manufactured by a dry process typified by a thin-film deposition method, and pattern processing is often realized by using a mask. That is, the mask is placed in front of the substrate on which the element is manufactured, and the organic layer or the electrode is deposited only on the mask opening.

【0008】

[Problems to be Solved by the Invention]

However, it is necessary to reduce the thickness of the mask in order to cope with fine patterns. Since the strength is not sufficient, the adhesion between the substrate and the mask deteriorates due to bending or the like. Therefore, in the conventional method, the finer the pattern, the more the portion where the vapor deposition wraps around the shadow of the mask cannot be ignored, and it is difficult to process the pattern of the device with sufficient accuracy. This is a big problem that can cause a short circuit of the element and crosstalk due to an increase in leakage current. For example, according to Japanese Patent Application Laid-Open No. 2-66873, it is shown that a pattern pitch of less than 300 μm is a pixel size that is considerably smaller than the range in which pattern processing by using a mask is possible.

【0009】

An object of the present invention is to solve such a problem and to provide a manufacturing method capable of achieving good pattern processing accuracy in an organic electroluminescent device that cannot use a wet process. In other words, it is not the purpose of simply fixing the mask to the substrate, but it exhibits sufficient adhesion between the mask and the substrate, which is necessary to realize fine pattern processing with the mask, which was not possible in the past. The purpose is to provide a method.

【0010】

[Means for solving problems]

In order to achieve the above object, the manufacturing method of the present invention is "in an organic electroluminescent device in which a light emitting layer made of an organic compound exists between an anode and a cathode, a pattern processed portion included in the device is a substrate by magnetic force. It is characterized in that it is formed through a mask that is in close contact with the electrode.

【0011】

BEST MODE FOR CARRYING OUT THE INVENTION

The organic electroluminescent device in the present invention is an element in which a light emitting layer made of an organic compound exists between an anode and a cathode and emits light by electric energy, and is a layer constituting an element such as an anode, a cathode, or a light emitting layer. At least one of them is patterned.

【0012】

The anode and cathode may be conductive enough to supply a sufficient current for light emission of the device, but it is desirable that at least one electrode is transparent in order to extract light.

【0013】

If the transparent electrode has a visible light transmittance of 30% or more, there is no major obstacle to its use, but ideally, it is preferable that the transparent electrode is close to 100%. Basically, it is preferable to have substantially the same transmittance over the entire visible light range, but if it is desired to change the color, it is possible to positively have absorption. In that case, it is technically easier to change the color using a color filter or an interference filter. The material of the transparent electrode is often composed of at least one element selected from indium, tin, gold, silver, zinc, aluminum, chromium, nickel, oxygen, nitrogen, hydrogen, argon and carbon, but copper iodide. , Inorganic conductive substances such as copper sulfide, and conductive polymers such as polythiophene, polypyrrole, and polyaniline can also be used, and are not particularly limited.

【0014】

Examples of particularly preferable anodes in the present invention include tin oxide, zinc oxide, indium oxide, and indium tin oxide (ITO) placed on a transparent substrate. In display applications where pattern processing is performed, ITO with excellent workability can be mentioned as a particularly suitable example. ITO may contain small amounts of metals such as silver and gold to reduce surface resistance and suppress voltage drops, and tin, gold, silver, zinc, indium, aluminum, chromium and nickel are used for ITO. It can also be used as a guide electrode for. Among them, chromium is a suitable metal because it can have the functions of both a black matrix and a guide electrode. From the viewpoint of device power consumption, it is desirable that ITO has a low resistance. For example, an ITO substrate of 300 Ω / or less functions as an element electrode, but since it is now possible to supply a substrate of about 10 Ω / , it is particularly desirable to use a low resistance product. The thickness of ITO can be arbitrarily selected according to the resistance value, but it is usually used between 100 and 300 nm. 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, and a glass substrate can be mentioned as a preferable example. Soda lime glass, non-alkali glass, etc. are used, and the thickness needs to be sufficient to maintain the mechanical strength, so 0.7 mm or more is sufficient. As for the material of the glass, non-alkali glass is preferable because it is better that there are few elution ions from the glass, but SiO₂Soda lime glass with a barrier coat such as is also available on the market and can be used. The ITO film forming method is not particularly limited, such as an electron beam method, a sputtering method, and a chemical reaction method.

【0015】

The cathode is not particularly limited as long as it is a substance capable of efficiently injecting electrons into the light emitting layer of this device. Therefore, it is possible to use low-work function metals such as alkali metals, but considering the stability of the electrodes, metals such as platinum, gold, silver, copper, iron, tin, aluminum, magnesium and indium, or these metals A preferred example is an alloy of and a low-working function metal. Further, by doping the organic layer with a small amount of a low work function metal in advance and then forming a relatively stable metal as a cathode, it is possible to obtain a stable electrode while maintaining high electron injection efficiency. The method for producing these electrodes may be a dry process such as resistance heating vapor deposition, electron beam deposition, sputtering, or ion plating method, but the present invention uses a resistance heating vapor deposition method that can be easily performed.

【0016】

The organic layers contained in the organic electroluminescent device include 1) hole transport layer / light emitting layer, 2) hole transport layer / light emitting layer / electron transport layer, 3) light emitting layer / electron transport layer, and 4) or more. It may be any of a light emitting layer in which the combinational substances of the above are mixed in one layer. That is, if a light emitting layer made of an organic compound exists as an element configuration, in addition to the multilayer laminated structure of 1) to 3) above, the light emitting material alone or the light emitting material and the hole transporting material or electron transporting as in 4). It may be sufficient to provide only one light emitting layer containing the material.

【0017】

The hole transporting layer is formed by the hole transporting substance alone or by the hole transporting substance and the polymer binder, and the hole transporting substances include N, N ́-diphenyl-N, N ́-di. (3-Methylphenyl) -1,1'-Diphenyl-4,4 ́-Diamine (TPD) and N, N ́-Diphenyl-N, N ́-Dinaphthyl-1,1'-Diphenyl-4,4 ́- Triphenylamines typified by diamines (NPD), tertiary amines such as N-isopropylcarbazole, pyrazoline derivatives, stilben compounds, hydrazone compounds, oxadiazole derivatives and heterocyclic compounds typified by phthalocyanine derivatives In the polymer system, polycarbonate, a styrene derivative, polyvinylcarbazole, polysilane, etc. having the monomer as a side chain are preferable, but are not particularly limited.

【0018】

Light emitting layer materials are mainly anthracene and pyrene, which have been known as luminescent materials for a long time, and in addition to the above-mentioned 8-hydroxyquinolin aluminum, for example, bisstyryl anthracene derivative, tetraphenylbutadiene derivative, coumarin derivative, and oxadiazole. Derivatives, distyrylbenzene derivatives, pyrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, oxadiazole derivatives, thiadiazolopyridine derivatives, polyphenylene vinylene derivatives, polyparaphenylene derivatives, polythiophene derivatives and the like can be used in the polymer system. .. As the dopant added to the light emitting layer, the above-mentioned rubrene, quinacridone derivative, phenoxazone 660, DCM1, perylene, perylene, coumarin 540, diazaindacene derivative and the like can be used as they are.

【0019】

As an electron-transporting substance, it is necessary to efficiently transport electrons from the cathode between electrodes to which an electric field is applied, and it is desirable that the electron injection efficiency is high and the injected electrons are efficiently transported. For that purpose, it is required to be a substance having a large electron affinity, a high electron mobility, excellent stability, and less likely to generate trap impurities during production and use. Derivatives that satisfy these conditions include 8-hydroxyquinoline aluminum and hydroxybenzoquinolinberylium, such as 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole (t). -Oxadiazole-based derivatives such as (BuPBD) and 1,3-bis (4-t-butylphenyl-1,3,4-oxadizolyl) biphenylene (OXD), which is an oxadiazole dimersible derivative with improved thin film stability. -1), 1,3-bis (4-t-butylphenyl-1,3,4-oxadizolyl) phenylene (OXD-7), triazole-based derivatives, phenanthroline-based derivatives, etc.

【0020】

The materials used for the above hole transport layer, light emitting layer, and electron transport layer can form each layer independently, but as a polymer binder, polyvinyl chloride, polycarbonate, polystyrene, poly (N-vinylcarbazole) , Polymethylmethacrylate, polybutylmethacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide, ethyl cellulose, vinyl acetate, ABS resin, polyurethane resin, and other solvent-soluble resins. It can also be dispersed in a curable resin such as a phenol resin, a xylene resin, a petroleum resin, a urea resin, a melamine resin, an unsaturated polyester resin, an alkyd resin, an epoxy resin, or a silicone resin.

【0021】

The method for forming the organic layer such as the hole transport layer, the light emitting layer, and the electron transport layer is not particularly limited, such as resistance heating vapor deposition, electron beam deposition, and sputtering method, but usually, resistance heating vapor deposition and electron beam. A vapor deposition method such as vapor deposition is preferable in terms of characteristics. The thickness of the layer cannot be limited because it depends on the resistance value of the organic layer, but empirically, it is selected from the range of 10 to 1000 nm.

【0022】

Electrical energy mainly refers to direct current, but pulse current and alternating current can also be used. The current value and voltage value are not particularly limited, but considering the power consumption and life of the device, the maximum brightness should be obtained with the lowest possible energy.

【0023】

The pattern-processed portion in the present invention basically means a portion involved in light emission of the organic electroluminescent element, but depending on the necessity, the contrast, pattern accuracy, and electrical insulation of the portion involved in light emission are improved. It is not particularly limited as it may be a non-emissive portion formed for the purpose of causing the light emission. Preferably, the light emitting layer, the anode, and the cathode are patterned.

【0024】

The light emitting layer and the electrodes are particularly important as the parts involved in light emission. These shapes and sizes are not particularly limited, and the most suitable ones are used depending on the application. For example, in display element and display applications, one or more light emitting regions defined by the pattern shape of the light emitting layer, the electrodes, and the non-light emitting region form one pixel. That is, it is not necessary that the pattern shape and size of the light emitting layer or electrode processed by the present invention match the shape and size of the pixel. The shape of the pixel differs depending on the display method such as the segment method or the dot matrix method, but the pixel size is preferably 2 mm square or less. For high-definition display applications, a pixel size of 500 μm square or less is desirable, and as a more suitable pixel size, 100 × 300 μm, which is a single-color single-pixel size of a full-color liquid crystal display currently in practical use, can be exemplified.

【0025】

In display applications, the pattern processing shapes of the light emitting layer and electrodes often have a repeating cycle. In that case, the minimum pitch of the pattern processing size is preferably 2 mm or less, and more preferably 500 μm or less. These displays may be a simple matrix type or an active matrix type represented by a TFT method, and the present invention does not limit the structure and drive method of the display.

【0026】

The above electrodes refer to at least one of an anode and a cathode in an organic electroluminescent device, and both electrodes may be patterned according to the present invention, if necessary. It also includes things like guide electrodes that are added to improve the conductivity of the electrodes. Basically, one electrode provided on the substrate is first patterned by a wet process, and after forming an organic layer on it, the other electrode is patterned by the method according to the present invention. Is preferable. A more preferable example includes a step in which a transparent electrode previously patterned on a transparent substrate is used as an anode, an organic layer is formed on the anode, and a cathode on the upper part of the organic layer is patterned according to the present invention.

【0027】

The non-light emitting portion to be patterned according to the present invention is not particularly limited, and preferred examples include a black matrix and an insulating layer for defining a light emitting region. The black matrix blackens the gaps in the light emitting region to improve the contrast. The insulating layer protects the electrode edges, defines the light emitting region, and improves the insulation between the electrodes. In either case, the material, shape, and size cannot be unequivocally indicated, and the most suitable one is used depending on the application.

【0028】

The mask in the present invention is a mask having one or more openings provided on a planar object such as a plate or a film. Organic substances or electrode materials that fly toward the substrate by the vapor deposition method are deposited on the substrate through the mask opening installed in front of the substrate, and pattern processing of the organic electroluminescent element corresponding to the shape of the mask opening is realized. Will be done.

【0029】

An important feature of the present invention is that the adhesion between the mask and the substrate is improved by a magnetic force. As a result, the proportion of the wraparound portion such as the vapor-deposited material, that is, the portion to be vapor-deposited so as to bleed from the mask opening to the shadow portion of the mask is reduced, and fine pattern processing that was impossible in the past is achieved. Ru. Since it is not the direct object of the present invention to positionally fix the mask to the substrate or to support the weight of the mask itself, it may be done by magnetic force or mechanical contact, and the method is particularly limited. It's not a thing.

【0030】

In the present invention, the relationship is not particularly limited as long as magnetic forces exert each other between the mask and one or more other objects. For example, if the mask and the substrate of the organic electric field light emitting element exert attractive forces by magnetic force, the substrate may be a magnet, the mask itself may be a magnet, or both may be magnets. Of course, the object that exerts a magnetic force on the mask does not have to be a substrate, and whether it is an attractive force or a repulsive force is not particularly limited. As a preferable example in the present invention, a mask exerted by an attractive force by a magnetic field, that is, a mask made of a material attracted to a magnet is installed on the front side of the substrate, which is the manufacturing surface of the organic electroluminescent element, and is arranged on the back side of the substrate. Examples thereof include a method in which the mask is brought into close contact with the substrate by means of a magnet. The amount of magnetic force required depends on the shape, size, weight, strength, etc. of the opening of the mask, so it cannot be unequivocally shown, but when the mask is fixed by mechanical contact, the required adhesion of the mask is required. It suffices if the magnetic force is more than sufficient to obtain, and if the mask is also fixed by the magnetic force, the magnetic force is sufficient to ensure the adhesion and positional fixing of the mask.

【0031】

Preferable examples of magnets include permanent magnets and electromagnets. The shape and size thereof are not particularly limited, but it is desirable that the size is larger than the mask opening so that the suction force in the direction perpendicular to the substrate surface acts uniformly on the entire opening of the mask. Further, although a magnetic field may be generated in an area required by one magnet, a plurality of magnets may be bonded together or arranged at predetermined intervals. The distance from the substrate is not particularly limited as long as the mask has a sufficient magnetic force.

【0032】

Suitable materials for permanent magnets include hardened hardened magnet materials such as pure iron, carbon steel, W steel, Cr steel, Co steel and KS steel, and precipitated hardened magnets such as MK steel, Alnico steel, NKS steel and Cunico steel. Examples include materials, sintered magnet materials such as OP ferrite and Ba ferrite, and various rare earth magnet materials typified by Sm-Co type and Nd-Fe-B type, but are not limited to the above. These materials are often used in bulk, but powder may be mixed with rubber or resin, or powder may be pressure-molded and used as a magnet.

【0033】

The electromagnet is particularly preferably used in the present invention because it can electrically control ON / OFF of magnetic field generation and magnetic force. The structure is not particularly limited, but it is particularly desirable that the magnetic core is inserted in the solenoid coil in which the lead wire is wound a plurality of times. As the magnetic core material, in addition to those listed above as permanent magnet materials, metal magnetic core materials such as silicon steel plate, Al-Fe alloy, Ni-Fe alloy (permalloy), Mn-Zn type, Ni-Zn type, etc. Examples include ferrite magnetic core materials such as Cu-Zn, and dust core materials obtained by compression molding fine powders such as carbonyl iron, Mopermalloy, and sendust together with a binder. Such an electromagnet may be used alone, but a plurality of electromagnets may be combined to serve as a magnetic field generation source.

【0034】

The above-mentioned magnetic material can also be mentioned as a suitable material for the mask. It is preferable to prepare a mask from a thin plate of these materials, but it is also possible to use a film in which powder of a magnetic material is mixed with rubber or resin, so that the material composition of the mask can be used. Cannot be unequivocally specified. In order to efficiently develop the attractive force of the magnet, the mask contains one or more of the magnetic elements Fe, Co, and Ni in a total composition ratio of 1% or more (in the case of one type, 1 alone). % Or more) is desirable, and it is more desirable to include a total of 20% or more. A magnetic field exerts an attractive force on the produced mask, but the mask itself may or may not be magnetized from the beginning. If necessary, the mask can be made from the magnetized material, or the mask can be made and then magnetized.

【0035】

The shape and size of the mask opening is basically equal to that of pattern processing of organic electroluminescent devices. However, certain pattern processing in an organic electroluminescent device may be realized at one time using one mask, a combination of a plurality of masks, a shift in the relative position between one mask and a substrate, and the like. Since it may be realized in a plurality of times, it is not necessary that both patterns match. When a pattern having a repetition period in the element is realized by one mask as in the above-mentioned display application, 2 mm can be exemplified as a preferable example of the pattern pitch of the mask, and 500 μm can be exemplified as a more preferable example.

【0036】

The thickness of the mask depends on its strength, size, and pattern size, so it cannot be unequivocally shown. If the mask is thicker than necessary and the strength of the mask is too high, a large magnetic force is required to improve the adhesion to the substrate, and it becomes difficult to make the mask follow the deflection of the substrate. As a guide, a thickness of 2 mm or less is a suitable example. The present invention is particularly effective for fine pattern processing, and 500 μm is exemplified as a more preferable example of the pattern pitch. In this case, for example, if the opening is 300 μm, the remaining width of the mask is 200 μm. In order to achieve good pattern accuracy, the thickness of the mask is preferably 5 times or less of the remaining width (200 μm in this case), and more preferably less than or equal to the remaining width. Therefore, as a more preferable thickness of the mask corresponding to fine pattern processing, 500 μm or less can be exemplified.

【0037】

When the surface of the substrate used for the organic electroluminescent element is flat, it is advantageous to use a mask having high flatness in order to realize uniform adhesion between the mask and the substrate. However, if the thickness of the mask is reduced as described above in order to cope with a fine pattern, the mask is easily deformed during the manufacturing process of the mask, and the mask may be wavy and the flatness may be impaired. is there. In such a case, the flatness of the mask may be improved by using a method such as annealing. Furthermore, the mask is often used in a state of being fixed to a frame of an appropriate shape, but even in that case, the flatness of the mask is brought closer to the ideal state by fixing the mask to the frame while applying tension to the mask. Should be done.

【0038】

In the manufacturing method of the present invention, in order to prevent the mask from damaging the organic layer formed on the substrate when the manufacturing surface of the organic electroluminescent device is brought into close contact with the mask, the non-light emitting portion of the organic electroluminescent device is used. It is preferable to arrange a spacer that acts as a cushion in the space. This spacer can also be used in whole or in part of the black matrix. The method and material for manufacturing the spacer are not particularly limited, but it is a process to arrange the spacer on the substrate in advance so that the light emitting part can be efficiently protected from the contact of the mask by using a photolithography method or the like. It is easy to do. The height of the spacer is higher than the thickness of the light emitting part of the organic electroluminescent element, and it is necessary to the extent that the pattern processing accuracy does not deteriorate due to the wraparound of the vapor deposition. It should be optimized according to the conditions.

【0039】

The function of the spacer is to partially provide a protrusion on the substrate contact surface of the mask and bring the protrusion into contact with the non-light emitting part of the organic electroluminescent element, or to make the entire surface of the mask relatively flexible such as resin. It can also be achieved by coating a substance. The material for the protrusions and the coating is not particularly limited, but it is easy to form by using a photoresist or the like.

【0040】

[Example]

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to these examples.

【0041】

Example 1 A mask having openings provided by wet etching was prepared on a 28 × 36 mm, 50 μm thick coval (composition ratio: Fe54%, Ni29%, Co17%) plate. The main part of one opening is rectangular, with short and long side lengths of 200 μm and 15 mm, respectively. This opening is repeated 16 times in the short side direction with a pitch of 300 μm. That is, the central portion is a striped mask having a pitch of 300 μm (opening width 200 μm, remaining width 100 μm) × 16 stripes. Further, in order to facilitate electrical connection with the outside, both sides of the rectangular opening in the long side direction are continuously widened to a pitch of 1.27 mm (opening width 600 μm) between 7.5 mm. The above mask is fixed by laser fusion to a 2 mm wide stainless steel frame with the same outer shape. This mask is fixed in the vacuum vapor deposition equipment so that the stainless steel frame side faces the vapor deposition source (lower side), and on the opposite edge plate side (upper side), a glass substrate with a thickness of 38 x 46 mm and a thickness of 1.1 mm. Plate magnets of 34 x 42 mm and 3 mm in thickness were placed and fixed in order. A rare earth magnet (H-23CV) manufactured by Hitachi Metals, Ltd. was used as the plate magnet. The degree of vacuum inside the device is 5 x 10^-4After exhausting to Pa or less, metallic Al was deposited at a rate of 1 nm / s at a rate of 150 nm by a resistance heating vapor deposition method using an alumina crucible. The substrate was rotated during the vapor deposition in order to average the film thickness distribution.

【0042】

Figure 1 shows a photograph of the glass substrate taken out after vapor deposition and the Al electrode deposited on the substrate surface observed with a microscope. The electrode width at the center in the long side direction was 200 μm. In addition, when the resistance value was measured with a tester using the part where the electrode pitch was widened, there was no electrical short circuit between the 16 electrodes, and the resistance between adjacent electrodes was 20 MΩ or more, which is the measurement limit. It was.

【0043】

Comparative example 1 When the Al electrode was patterned in the same manner as in Example 1 except that a magnet was not used during the vapor deposition, the average value of the electrode width was 270 μm as shown in FIG. However, large wraparound of the deposited Al was observed at multiple locations, and 10 sets of adjacent electrodes out of 16 were electrically short-circuited.

【0044】

Example 2 The Al electrode was patterned in the same manner as in Example 1 except that the opening width was 250 μm and the remaining width was 50 μm (the pitch is the same as 300 μm). Figure 3 shows a photograph of the vapor-deposited Al electrode observed under a microscope. The electrode width was 255 μm. In addition, there was no electrical short circuit between the electrodes, and the resistance between adjacent electrodes was 20 MΩ or more, which is the measurement limit.

【0045】

Comparative example 2 When the Al electrode was patterned in the same manner as in Example 2 except that a magnet was not used during the vapor deposition, as shown in FIG. 4, all the adjacent electrodes overlapped each other, and the electrode width could not be measured. .. Even in the measurement of the resistance value, all the adjacent electrodes were electrically short-circuited.

【0046】

Example 3 A 1.1 mm thick glass substrate with an ITO transparent electrode film (electron beam vapor deposition, 15 Ω / ) is cut to a size of 38 x 46 mm, and ITO is pitched by a photolithography method at a pitch of 300 μm (ITO remaining width 270 μm) ×. The pattern was processed into 32 stripes. One side of the ITO stripe in the long side direction is widened to a pitch of 1.27 mm (opening width 800 μm) to facilitate electrical connection with the outside. The substrate was washed and treated with UV-ozone. This is fixed in the vacuum vapor deposition equipment, and the degree of vacuum in the equipment is 2 × 10.^-4Exhausted until it was below Pa. Bis (m-methylphenylcarbazole), which is a hole transport material, was vapor-deposited from a tantalum boat at a rate of 0.3 nm / sec by a resistance heating method at 120 nm, and 8-hydroxyquinoline aluminum (Alq3) doped with 0.35 wt% quinacridone was 0.3. 30 nm was deposited at a rate of nm / sec, and 70 nm was sequentially deposited at a rate of 0.3 nm / sec for Alq3. The above deposition of organic matter was carried out on the entire surface of the substrate. Next, using a magnet as in Example 1, the mask was set so that the stripe patterns of the ITO and the electrodes were orthogonal to each other. In vacuum, the already formed organic layer was exposed to lithium vapor for doping (thickness conversion amount: 1 nm), and then Al was deposited to a thickness of 150 nm at a rate of 0.5 nm / sec.

【0047】

When the obtained 32 × 16 pixel simple matrix organic electroluminescent device was made to emit light by linear drive, clear character display was possible. A photograph of the light emitting region observed with a microscope is shown in FIG. One pixel was 270 μm x 255 μm, and the length of each side corresponded to the actual patterned ITO and Al electrode widths.

【0048】

Example 4 As a mask for the light emitting layer, a mask having an opening in a Ni plate having an outer diameter of 120 × 84 mm and a thickness of 25 μm was prepared. The basic shape of the opening is a stripe with a length of 67.2 mm and a width of 100 μm, and 272 lines are lined up in the width direction with a pitch of 300 μm. As schematically shown in FIG. 6, each striped opening 2a has a crossover 3 having a width of 20 μm every 4.8 mm in order to prevent deformation of the opening. As a cathode mask, a mask having an opening formed by wet etching on a Koval plate having an outer diameter of 120 × 84 mm and a thickness of 100 μm was prepared. As schematically shown in FIG. 7, each striped opening 2b has a length of 100 mm and a width of 270 μm, and 100 lines are arranged in the width direction at a pitch of 600 μm. The above two types of masks were fixed to a stainless steel frame having the same outer shape and a width of 2 mm by an electron beam welding method, taking care not to impair the flatness.

【0049】

A glass substrate 10 having the same ITO transparent electrode film as in Example 3 is cut into a size of 120 × 100 mm, and ITO is 100 μm pitch (ITO remaining width 90 μm) × 816 pieces by a normal photolithography method as shown in FIG. The pattern was processed into stripe 20 of. Next, a paste obtained by mixing a non-photosensitive polyimide with a black pigment containing a phthalocyanine-based oxidative condensate as a main component was applied onto the substrate by a spin coating method, and the paste was applied at 140 ° C. for 10 minutes in a nitrogen atmosphere in a clean oven. Semi-cure was performed. After patterning the polyimide layer by a normal photolithography method using a positive photoresist, it is cured at 280 ° C for 30 minutes to form a 1.0 μm-thick black layer that also serves as a spacer and a black matrix. Formed. As shown in FIG. 9, the black layer 30 is provided with an opening 31 having a size of 70 × 250 μm, and the central portion of the underlying ITO stripe 20 is exposed from the opening. The volume resistivity of the black layer is 10⁸It was Ω cm or more and had good insulation.

【0050】

After cleaning this substrate and applying UV-ozone treatment, it is fixed to a vacuum vapor deposition machine and the degree of vacuum inside the device is 2 × 10.^-4Exhausted until it was below Pa. First, copper phthalocyanine at 20 nm and bis (m-methylphenylcarbazole) at 100 nm were vapor-deposited on the entire surface of the substrate to form the hole transport layer 32, respectively, as hole transport materials. Next, a mask for a light emitting layer was placed in front of the substrate, and a ferrite-based plate magnet having a thickness of 110 mm, a thickness of 10 mm, and a residual magnetic flux density of 0.3 T was placed behind the substrate to fix them. At this time, the center lines of the striped opening 2a of the mask and the ITO stripe 20 of the substrate were aligned, and the crossover lines 3 were aligned so as not to interfere with the black layer opening 31. Bis (2-methyl-8-hydroxyquinolinolato) -paraphenylphenoratoaluminum (BAlq) doped with 0.3 wt% perylene as the blue light emitting layer 40 in vacuum₃) To 30 nm, and BAlq₃Was sequentially deposited at 70 nm. After shifting the light emitting layer mask by 1/3 pitch with respect to the substrate, the substrate and the magnet were fixed, and 0.3 wt% quinacridone was doped as a green light emitting layer 41 on the adjacent ITO stripe.₃30nm, plus Alq₃Was sequentially deposited at 90 nm. Similarly, Alq doped with 0.3 wt% 4- (dicyanomethylene) -2-methyl-6- (paradimethylaminostyryl) -4-pyran (DCM) as a red light emitting layer 42 on the adjacent ITO stripe.₃30nm, plus Alq₃Was sequentially deposited at 80 nm. As shown in Fig. 10, each light emitting layer is arranged every three ITO stripes 20 and completely covers the exposed portion of ITO. After that, the mask for the light emitting layer is removed, and Alq is used as the light emitting layer coating layer 43 on the entire surface of the substrate.₃Was deposited at 20 nm. Next, the cathode mask was placed in front of the substrate, and the same magnets as described above were placed behind the substrate to fix them. At this time, the stripe-shaped opening 2b of the mask was positioned so as to be orthogonal to the ITO stripe 20 of the substrate and to coincide with the center of the black layer opening 31. In a vacuum, the already formed organic layer was exposed to lithium vapor for doping (thickness conversion amount: 1 nm), and then Al was vapor-deposited to a thickness of 200 nm to form a cathode. At this stage, the cathode 50a has a pitch of 600 μm (electrode width 275 μm) as shown in FIG. Furthermore, after shifting the cathode vapor deposition mask by 1/2 pitch with respect to the substrate, the substrate and the magnet are fixed, and Li doping and Al cathode vapor deposition are performed in the same manner, so that the gap between the cathodes formed the first time is formed. A cathode 50b having the same electrode width was formed on the surface. As schematically shown in FIGS. 12 and 13, red, green, and blue (RGB) light emitting layers are finally arranged alternately on 816 ITO stripes, and 200 cathodes having a pitch of 300 μm are orthogonal to the ITO. A simple matrix type color display lined up with books was obtained. Since the three light emitting regions composed of RGB form one pixel, this display has 272 × 200 pixels at a pitch of 300 μm. In FIG. 13, the thickness of the black layer 30 is drawn thinner than the light emitting portion for ease of explanation, but it is actually formed thicker than the light emitting portion to protect the light emitting portion from contact with the mask. It fully fulfilled the function as a spacer.

【0051】

When the produced display was made to emit light, each light emitting region emitted light in an independent color of RGB, and when the light emitting layer was vapor-deposited, the bleeding of the emitted color due to the vapor deposition wrapping around to other light emitting regions was observed. I was not able to admit. Similarly, there was no short circuit between the striped cathodes. The size of the light emitting region was 70 × 250 μm, which was consistent with the opening size of the black layer. In addition, it was possible to display a clear pattern and make it multicolored by sequentially driving the lines.

【0052】

[Effect of the invention]

According to the present invention, an organic electroluminescent device having good pattern processing accuracy can be manufactured without using a wet process.

[Simple explanation of drawings]

[Figure 1]

It is a micrograph of the pattern of the Al electrode processed by Example 1. FIG.

[Figure 2]

It is a micrograph of the pattern of the Al electrode processed by Comparative Example 1.

[Fig. 3]

It is a micrograph of the pattern of the Al electrode processed by Example 2.

[Fig. 4]

It is a micrograph of the pattern of the Al electrode processed by Comparative Example 2.

[Fig. 5]

It is a micrograph of the pattern of the pixel part of the organic electroluminescent device which was pattern-processed by Example 3.

[Fig. 6]

It is a top view explaining the outline of the mask for a light emitting layer used in Example 4. FIG.

[Fig. 7]

It is a top view explaining the outline of the cathode mask used in Example 4. FIG.

[Fig. 8]

It is a top view explaining the outline of the organic electroluminescent element of Example 4 (ITO pattern processing stage).

[Fig. 9]

It is a top view explaining the outline of the organic electroluminescent device of Example 4 (black layer formation stage).

[Fig. 10]

It is a top view explaining the outline of the organic electroluminescent element of Example 4 (RGB light emitting layer formation stage).

[Fig. 11]

It is a top view explaining the outline of the organic electroluminescent device of Example 4 (the first cathode formation step).

[Fig. 12]

It is a top view explaining the outline of the organic electroluminescent device produced in Example 4.

[Fig. 13]

It is a cross-sectional view of AA'of FIG.

[Explanation of symbols]

1a, 1b mask part 2a, 2b Striped openings 3 Crossover 10 Glass substrate 20 ITO stripe 30 black layer 31 Black layer opening 32 hole transport layer 40 blue light emitting layer 41 Green light emitting layer 42 Red light emitting layer 43 Light emitting layer coating layer 50a, 50b cathode