JP4696832B2 - Method for manufacturing organic electroluminescence panel - Google Patents

Description

  The present invention relates to a method for manufacturing an organic EL panel in which a protective film is formed on an organic electroluminescence (EL) element.

  In recent years, organic EL elements have attracted attention as self-luminous elements. An organic EL device is a device in which a light emitting layer made of a thin organic compound is sandwiched between electrodes on a substrate such as glass and emits light when a current is supplied between the electrodes.

  In order to mass-produce organic EL elements at low cost, production techniques have been devised in which organic EL elements are formed on a flexible substrate such as a resin film by a roll-to-roll method (see, for example, WO01 / 005194).

  Since the organic EL element is deteriorated by moisture or oxygen, it is necessary to perform sealing that completely blocks the outside air from the viewpoint of reliability. In the conventional roll-to-roll system, after forming the organic EL element on the flexible substrate that has been unwound from the roll in a vacuum environment, it is wound around the roll again, and then transferred to a container filled with an inert gas from the vacuum environment. It is transported to the next process.

  However, the environment in the container of the inert gas is not sufficiently reduced in moisture and oxygen as compared with the vacuum environment when the organic EL element is formed. Therefore, there is a high possibility that the organic EL element is deteriorated and the product life is shortened when the inert gas is sealed before being sealed.

  On the other hand, as a thin film sealing method, a method of covering an organic EL element with a stable thin film barrier film such as a nitride film or a nitrided oxide film is known. The barrier film is formed in a vacuum environment by a thin film forming method such as an electron beam method, a sputtering method, a plasma CVD method, an ion plating method, etc., and even a high melting point material or compound can be formed relatively easily. is there.

  As a conventional technique of the barrier film forming method, Patent Document 1 discloses a technique of a target-type sputtering apparatus. However, in the conventional barrier film, when cracks are generated due to the surface state of the protrusions of the organic EL element, the moisture permeability becomes insufficient particularly in a high temperature and high humidity environment. In addition, due to insufficient film strength of the barrier, scratch resistance due to external factors was not sufficient.

  As another sealing method, Patent Document 2 discloses a technique of attaching a sheet-shaped sealing member to an organic EL element. However, when such a sealing operation is performed in an atmospheric pressure environment, deterioration of the organic EL element due to moisture or oxygen becomes a problem.

The present invention has been made in view of the above points, and an object thereof is to provide a method for manufacturing an organic EL panel in which performance deterioration due to a sealing process of an organic EL element produced by a roll-to-roll method is reduced. .
JP 2002-332567 A JP 2005-4063 A

  Accordingly, an object of the present invention is to produce an organic EL panel with reduced production load when forming a protective film without reducing barrier resistance against moisture and oxygen even in an organic EL panel produced by a roll-to-roll method. It is to provide a method.

  The above-mentioned problem to be solved by the present invention is achieved by the following means.

1. In a method for manufacturing an organic electroluminescence panel by a roll-to-roll method, in which an organic electroluminescence element is formed on a flexible substrate and a protective film is formed on the organic electroluminescence element, the first in-line following the formation of the organic EL element. After forming the protective film, after passing through a preliminary chamber for adjusting the degree of pressure reduction, it is wound up in a roll shape under an atmospheric pressure environment, and thereafter, in an atmospheric pressure environment, offline, separately from the step of forming the organic EL element. A method for producing an organic electroluminescence panel, further comprising forming a second protective film.

  2. 2. The organic electroluminescence according to 1, wherein the first protective film is formed by any one of an electron beam method, a sputtering method, a plasma CVD method, and an ion plating method in a vacuum environment. Panel manufacturing method.

  3. 3. The method of manufacturing an organic electroluminescence panel according to 1 or 2, wherein the first protective film is either silicon nitride oxide or silicon nitride.

  4). 4. The organic electrophoretic material according to any one of 1 to 3, wherein the formation of the second protective film is performed under an atmospheric pressure environment and under dry conditions having a dew point temperature of −10 ° C. or lower. Manufacturing method of luminescence panel.

  5. The said 2nd protective film is formed by sticking a resin film on the flexible substrate in which the said organic electroluminescent element and the 1st protective film were formed, Any one of said 1-4 characterized by the above-mentioned. Manufacturing method of organic electroluminescence panel.

  6). 6. The method for producing an organic electroluminescence panel according to 5, wherein a third barrier film is formed in advance on the resin film.

  7). 7. The method of manufacturing an organic electroluminescence panel according to 5 or 6, wherein the resin film is attached through an intermediate layer.

  By this invention, the manufacturing method of the organic electroluminescent panel which reduced the performance degradation by the sealing process of the organic electroluminescent element produced by a roll toe roll system was provided.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  The roll-to-roll system in the present invention is a roll of a continuous flexible substrate having a length of, for example, several hundred meters and a width of about 1 meter, such as a film, and is intermittently or continuously conveyed while being conveyed. In this method, an organic EL element is formed on a flexible substrate and wound around a roll again.

  Before and after the step of forming the organic EL element, a circuit pattern for driving the element or a protective film covering the element may be bonded and wound on a roll.

  Comparing the single-wafer method and the roll-to-roll method, which transports individually separated substrates for each process, the single-wafer method requires the provision of a substrate loading and unloading unit for each process, and a device for each process. Although the scale tends to increase, in the roll-to-roll method, the substrates flow intermittently or continuously between the steps, so that the steps can be connected to each other, and the work involved in substrate transportation can be reduced and the apparatus can be downsized.

  In the roll-to-roll system in the present invention, in-line means that the roll-shaped flexible substrate is in the process from being fed out to the process of forming the organic EL element and wound up, and offline means organic This is a process after the flexible substrate on which the EL element is formed is wound up on a roll.

Further, the vacuum condition in the present invention means an environment under a pressure environment of 1 × 10 ⁻¹ Pa or less, which is an environment where there is little residual moisture and oxygen and deterioration of the organic EL element is reduced. The atmospheric pressure environment means a pressure environment of 10,000 Pa to 200,000 Pa, and is an environment where much moisture and oxygen remain as compared with a vacuum environment.

(Embodiment of the Invention)
Hereinafter, the present invention will be described with reference to embodiments.

  An example of an embodiment according to the present invention will be described below with reference to the drawings.

  First, the organic EL element will be described below.

FIG. 1 is a schematic diagram of an organic EL element 10.
In the figure, an organic EL element 10 is an element in which a first electrode 12, an organic layer 13, and a second electrode 14 are laminated on a substrate 11.

  The first electrode 12 is an anode, and when transparent, indium tin oxide (ITO), indium zinc oxide (IZO), gold, tin oxide, zinc oxide and the like have a work function of 4 eV or more and a transmittance of 40%. This is an electrode made of the above conductive material.

  The organic layer 13 is a single layer or a plurality of layers made of an organic material such as an organic compound or a complex of several nm to several μm including the light emitting layer. For example, the light emitting device includes a hole transporting layer in contact with the anode and a light emitting material. 3 layers of an electron transport layer in contact with the cathode, a lithium fluoride layer, an inorganic metal salt layer, or a layer containing them may be disposed at an arbitrary position.

  The second electrode 14 is a cathode and is an electrode made of a metal material having a work function of less than 4 eV and a reflectivity of 60% or more, such as aluminum, sodium, lithium, magnesium, silver, calcium, etc. is there.

  The substrate 11 is made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC) as a base material. , Cellulose triacetate (TAC), cellulose acetate propionate (CAP) and the like.

  The organic EL element in the present invention is produced by the combination of electrons and holes in the organic layer 13 due to the current supplied from the outside through the first electrode (anode) 12 and the second electrode (cathode) 14. The light emitted from the organic layer 13 is extracted through the first electrode (anode) 12. Examples of light emission using excitation energy include fluorescence that uses singlet excitation energy for light emission, and phosphorescence that uses triplet excitation energy for light emission. In particular, phosphorescence is desirable light emission as a light source because triplet excitons contribute to light emission, and thus higher light emission efficiency can be obtained than fluorescence.

  Light emitted from the light emitting layer of the organic EL element 10 is extracted through the first electrode 12 and the substrate 11. The second electrode (cathode) is formed by laminating a thin film cathode material and a highly transparent anode material. A so-called top emission configuration in which light is extracted from the cathode may be configured so as to be substantially transparent.

  The present invention is a method for producing an organic EL panel in which a gas barrier protective film (barrier film) is formed on these organic EL elements, and is shielded and sealed from gases such as water and oxygen in the atmosphere. The protective film comprises a first barrier film and preferably a second barrier film made of resin.

  Next, a manufacturing process for forming the organic EL element or the organic EL panel according to the present invention will be described below.

  FIG. 2 is a block diagram of an organic EL panel manufacturing process.

  The organic EL panel manufacturing method of the present invention includes an organic EL element forming step 120, a first protective film forming step 130, a second protective film forming step 140, etc., and in the roll-to-roll manufacturing process, The flexible substrate is sent out, and after forming the organic EL element in the organic EL element forming step 120, the first barrier film is formed in the first in-line protective film forming step, and the formed flexible substrate is rolled. The rolled organic EL element and the substrate on which the first barrier film is formed are then taken off-line, and the flexible organic EL element on which the first protective film is formed is transferred from here. 2 is a manufacturing method in which the second barrier film is formed in the second protective film forming process.

  The substrate is a substrate on which the first electrode (anode) is patterned in advance. Patterning for electrode formation may be performed in-line as in the conventional roll-to-roll method, but there is a concern of short-circuiting between organic EL element electrodes due to scattering of metal powder during electrode formation. It is necessary to take measures to block the powder from forming the organic EL element.

  The substrate pattern is an active type in which electrodes are patterned on the surface for lighting applications, an active type in which TFTs are arranged in a matrix in advance, or a passive pattern in which wiring is patterned in a matrix. It may be a type.

  The cleaning process 110 is a process in which a flexible substrate wound in a roll shape is fed out, dry cleaning such as plasma cleaning, wet cleaning such as drying after being immersed in an ultrasonic cleaning tank, or a combination of dry and wet In this step, the substrate is cleaned.

  The organic EL element formation process 120 is a process in which an organic EL element is formed by a known technique such as a vapor deposition method, an ink jet method, a printing method, or a coating method.

  The first protective film forming step 130 is a step of forming the first barrier film in-line after the organic EL element forming step, and the film forming method is an electron beam method, a sputtering method, a plasma CVD method, an ion plate method. In this process, the first barrier film is formed so as to cover the organic EL element in a vacuum environment by a thin film manufacturing method such as a coating method.

  In the second protective film forming step 140, after winding the flexible substrate on which the organic EL element and the first barrier film are formed in a roll shape, the substrate is taken out of the roll again offline, and the first barrier is formed. On the substrate on which the film is formed, the thickness of the first barrier film is more than twice that of the first barrier film by an ink jet method, a printing method, a coating method, or another barrier film in an atmospheric pressure environment. In this step, the resin layer is formed as a second barrier film.

  In the second protective film forming step, as a method of forming the resin layer as the second barrier film, a method in which a resin film is attached to the flexible substrate on which the organic electroluminescence element and the first protective film are formed. Is preferred.

  Thus, the organic EL panel manufactured by forming the second protective film off-line and sealing it is wound up in a roll shape.

  In this way, when the barrier film is formed by a thin film forming method such as the electron beam method, the sputtering method, the plasma CVD method, the ion plating method or the like in a vacuum environment, the atmospheric pressure environment with a large amount of residual gas is subsequently performed off-line. In the formation of the second protective film below, the organic EL element can be sealed without being exposed to these residual gases.

  Next, the detail of the specific manufacturing process of the organic EL panel of this invention is demonstrated below.

  FIG. 3 is a schematic diagram of a manufacturing process of the organic EL panel of the present invention.

  The flexible substrate 10 wound in a roll is fed into a cleaning process 110, immersed in an ultrasonic cleaning tank 111 and subjected to ultrasonic cleaning, and then rinsed with pure water in a rinsing tank 112 and a shower head 113. And is dried in the drying zone 114.

  Thereafter, the transfer speed for the subsequent process is adjusted by the buffer zone 115, and is transferred to the plasma tank 116 through the preliminary chamber a (116 a) and the preliminary chamber b (116 b). A gate valve 117 for passing a film-like base material is provided between each preliminary chamber entrance, between the preliminary chambers, and between the preliminary chamber and the plasma tank. The gate valve 117 is provided with an orifice (a valve is formed so that the gap can be adjusted) so that the substrate surface, particularly the surface on the organic EL element formation side, can pass through without contact. Thus, the degree of decompression is adjusted by the differential evacuation by the decompression preliminary chamber 116a, another decompression preliminary chamber 116b, and the substrate, and the substrate is carried into the plasma chamber.

  Each decompression preparatory chamber and the plasma chamber are differentially evacuated by a vacuum pump (not shown) provided, so that the vacuum chamber required by the plasma chamber is changed from the atmospheric pressure environment to the plasma chamber. Adjusted. Although two decompression preliminary chambers are shown here, the decompression may be performed in three or more multistages. Here, the substrate enters the plasma chamber through two preliminary chambers.

In the plasma tank 116, the substrate is cleaned with oxygen plasma in a vacuum environment of 1 × 10 ⁻⁴ Pa, for example.

  After the cleaning, the substrate 10 is then transferred to the organic EL element forming step 120.

The vapor deposition tank 121 in which the organic EL element is formed is also in a vacuum environment at a pressure of 1 × 10 ⁻⁴ Pa or less, and a spare chamber 121a is also provided to avoid the exhaust gas from the cleaning tank due to the oxygen plasma. It is done. That is, a gate valve is provided between the plasma chamber and the preliminary chamber, and between the preliminary chamber and the vapor deposition chamber, and the orifice gap is adjusted so that the cleaned surface does not come into contact. Further, a pump (not shown) is connected to the preliminary chamber and exhausted to adjust the pressure and to separate the plasma tank and the vapor deposition tank.

In the formation step 120 of the organic EL element, while the conveyance is adjusted by the buffer zone 115, the portion where the marking hole 15 provided in the end portion of the substrate 10 is opened at the time of forming the organic EL element is in the vapor deposition tank. When it reaches a predetermined position, the conveyance is stopped, and vapor deposition is performed in the vapor deposition tank 121. In the vapor deposition tank 121, an organic material or a metal material is sublimated from the vapor deposition source 122 in a vacuum environment with a pressure of 1 × 10 ⁻⁴ Pa or less, and a predetermined pattern on the anode of the substrate 10 by the mask 123. An organic layer and a cathode are laminated to form an organic EL element.

For example, in the case of an organic EL device having an anode / hole transport layer / light emitting layer / cathode structure, the organic EL device has a hole transport layer (α-NPD) on the substrate on which the anode is formed; Layers (Alq ₃ ); sequentially formed with a thickness of 600 mm, and then a cathode (aluminum) is deposited thereon with a thickness of 2000 mm.

  Next, the substrate 10 on which the organic EL element is formed is transported to the first protective film forming step 130 through the spare chamber 131a.

  The barrier film as the first protective film is a film containing at least one kind of metal oxide film, oxynitride film, nitride film, metal thin film, and diamond-like carbon film, and is a thin film having a thickness of 50 nm to 50 μm. is there.

  Preferred metals are metals such as silicon and aluminum. Examples of preferred barrier film materials include silicon oxynitride and silicon nitride.

  Therefore, here, a sputtering apparatus, for example, an RF magnetron sputtering apparatus is used.

  In the first protective film forming step 130, similarly to the organic EL element forming step 120, the conveyance stops at a predetermined position of the marking hole 15 provided in the end portion of the substrate 10, and the predetermined position is set in the sputtering tank 131. Sputtering is performed.

In the sputtering chamber 131, an organic EL element formed on the substrate 10 by sputtering the target 132 with the sputtering gas plasma generated in the counter target 132 in a vacuum environment with a pressure of 10 ⁻¹ Pa or less by sputtering gas. A first barrier film is formed to cover the film.

The target 132 is made of the same material as the constituent material of the barrier film formed in the organic EL element or the same material as the constituent material by reaction with the sputtering gas. For example, a silicon oxynitride film is formed using, for example, argon containing 5% by volume of oxygen as a sputtering gas and Si ₃ N ₄ as a target.

In addition, since the vapor deposition process, which is a pre-process, is in a vacuum environment at a pressure of 1 × 10 ⁻⁴ Pa or less, the same process as described above is performed between the organic EL element forming process 120 and the first protective film forming process 130. In the preliminary chamber 131a provided with a gate valve, the degree of decompression is adjusted by differential exhaust.

  Thus, the flexible substrate 10 in which the organic EL element and the first barrier film are sequentially formed in-line exits the sputtering tank 131 and sequentially enters the spare chambers 131b and 131c having gate valves for adjusting the degree of pressure reduction. Passing through, the pressure reduction is gradually released by differential evacuation, it is taken out from the vacuum environment to the atmospheric pressure environment, wound up in a roll shape, and transported to the next off-line process.

  The second protective film forming step 140 environment, which is the next step after being taken out in an atmospheric pressure environment and wound up in a roll, is in addition to the atmospheric pressure environment of approximately tens of thousands to hundreds of thousands of Pa, It is controlled in a dry environment with a dew point temperature of −10 ° C. or lower. Here, the first barrier film is already formed on the organic EL element, and sufficient resistance to moisture is ensured in a dry environment, so that it is not necessary to use a vacuum environment.

  The second protective film forming step will be described with reference to FIG.

  The second protective film forming step 140 includes a coating unit 141, a laminating unit 143, a curing unit, a cutting unit, a sealing film 145, and the like.

  The applying unit 141 is a unit for attaching an adhesive layer 142 for forming the second barrier film to the organic EL element, and the adhesive layer may be used by applying an adhesive or the like that is cured by ultraviolet rays. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print it like screen printing.

  Further, instead of the application unit 141, an adhesive sheet as disclosed in Japanese Patent Application Laid-Open No. 2005-4063 may be used which is attached in advance to a sealing film 145 that is a protective film.

  The laminating means 143 is a means for laminating the sealing film 145 fed from the long roller on the adhesive layer 142. In the laminating method, the sealing film 145 is laminated on the first barrier film via the adhesive 142 by pressing or heating the upper and lower rollers, or pressing and heating.

  The curing unit 144 is a unit that cures the adhesive layer 142 and attaches the sealing film 145. When the adhesive is an ultraviolet curable resin, for example, a UV light source such as a halogen lamp is irradiated and cured by a photoreaction, and when the adhesive uses thermal curing, the adhesive is cured by heating to a predetermined temperature.

  The cutting means 146 is a means for cutting the substrate 10 into a predetermined size. The cutting may be performed by a cutter that moves up and down, or a circular rotating cutter that suppresses vibration.

  In the substrate 10 on which the organic EL element and the first protective film formed in the second barrier film forming step are formed, the ultraviolet curing adhesive is sent out at a predetermined flow rate by the syringe 141 on the first barrier film. And is applied at a predetermined thickness.

  Thereafter, the sealing film 145 and the substrate 10 are laminated with an adhesive by a laminating means. The substrate 10 on which the sealing film 145 is laminated on the first barrier film via the adhesive tank 142 is irradiated with a UV light source 144 for a predetermined time to cure the adhesive layer.

  As the sealing film, a flexible (thickness 10 μm to 1 mm) resin film such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, ethylene polyvinyl alcohol, ethylene vinyl acetate, ETFE or the like is used. Also, a laminated film such as a film in which an ethylene vinyl acetate film and an Asahi Glass ETFE (Aflex thickness 25 μm) weather-resistant resin are bonded together may be used.

  Further, a third barrier film may be formed in advance on these films for sealing. For example, a metal oxide film, an oxynitride film, a nitride film, which is the first protective film, A thin film having a thickness of 50 nm to 50 μm, such as a metal thin film. This further enhances the sealing function. Specifically, there are an alumina vapor deposition film, a metal foil laminated with a resin film, and the like.

  Further, as the adhesive, specifically, for example, an epoxy-based, acrylic-based, acrylic-urethane-based ultraviolet curable resin, or the like can be used. Further, a thermosetting resin may be used. Application | coating of the adhesive agent to a sealing part may use a commercially available dispenser as above-mentioned, and may print like screen printing.

  Moreover, not only this but an adhesive sheet as disclosed by Unexamined-Japanese-Patent No. 2005-4063 may be affixed on a sealing film.

  Then, the cutting means 146 cuts the organic EL element of a predetermined size along the marking hole 15. A cutter or the like can be used as the cutting means. However, the cutting means is not limited to the cutter, and it is good to use less cutting waste when a circular rotating cutter with vibration is used.

  As described above, preferred embodiments of the method for producing an organic EL panel by the method of the present invention have been shown.

  In the manufacturing method of the present invention, since the first barrier film is formed in advance, the step of forming the second barrier film can be performed in an off-line step after winding the substrate 10. For this reason, it is not necessary to adjust the conveyance speed and process time of the off-line process of a post process in connection with the in-line process which forms an organic EL element, and the working time corresponding to each process can be selected.

  In the in-line process, the cleaning process and the organic EL element film forming process are separated by the buffer zone. However, the present invention is not limited to this. The substrate may be sent out again in the forming step to form the organic EL element.

  In the off-line process, since the first barrier film is already formed, damage to the organic EL element due to moisture and oxygen is reduced, so that the work environment does not need to be in a vacuum environment. Therefore, it is not necessary for the apparatus for forming the second barrier film that is off-line to correspond to vacuum, and the cost of the film forming apparatus is reduced. Accordingly, the process of forming the second barrier film can be performed in a vacuum environment because, for example, a repair work for a wrinkle failure occurring in the bonding process and a maintenance work such as replacement of a cutter used in the cutting process can be performed in an atmospheric pressure environment. Compared with the case where the work is performed by returning to the atmospheric pressure environment from the bottom, the work efficiency can be improved and the process stop time can be shortened.

1 is a schematic diagram showing a configuration of an organic EL element 10. FIG. It is a block diagram which shows the manufacturing process at the time of barrier film formation. It is a schematic diagram of the manufacturing process of the organic electroluminescent panel of this invention. It is a figure explaining the 2nd protective film formation process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Organic EL element 11 Board | substrate 12 Anode 13 Organic layer 14 Cathode 110 Cleaning process 120 Organic EL element formation process 130 1st protective film formation process 140 2nd protective film formation process

Claims (7)

In a method for manufacturing an organic electroluminescence panel by a roll-to-roll method, in which an organic electroluminescence element is formed on a flexible substrate and a protective film is formed on the organic electroluminescence element, the first in-line following the formation of the organic EL element. After forming the protective film, after passing through a preliminary chamber for adjusting the degree of pressure reduction, it is wound up in a roll shape under an atmospheric pressure environment, and thereafter, in an atmospheric pressure environment, offline, separately from the step of forming the organic EL element. A method for producing an organic electroluminescence panel, further comprising forming a second protective film. 2. The organic electro of claim 1, wherein the first protective film is formed by any one of an electron beam method, a sputtering method, a plasma CVD method, and an ion plating method in a vacuum environment. Manufacturing method of luminescence panel. 3. The method of manufacturing an organic electroluminescence panel according to claim 1, wherein the first protective film is either silicon nitride oxide or silicon nitride. The organic material according to any one of claims 1 to 3, wherein the formation of the second protective film is carried out under an atmospheric pressure environment and under dry conditions having a dew point temperature of -10 ° C or lower. Manufacturing method of electroluminescence panel. The said 2nd protective film is formed by sticking a resin film on the flexible substrate in which the said organic electroluminescent element and the 1st protective film were formed, The any one of Claims 1-4 characterized by the above-mentioned. The manufacturing method of the organic electroluminescent panel of description. 6. The method of manufacturing an organic electroluminescence panel according to claim 5, wherein a third barrier film is previously formed on the resin film. The method for producing an organic electroluminescence panel according to claim 5 or 6, wherein the resin film is attached through an intermediate layer.

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