WO2005096675A1 - Method for manufacturing luminous panel - Google Patents

Abstract

A method for manufacturing a luminous panel containing a luminous article formed on a plastic substrate, characterized in that it comprises a step of forming the above luminous article at a treating temperature lower than the glass transition temperature or the heat resistance temperature representing the long term heat resistance of the above plastic substrate, and a step of forming a structure such as a barrier film in the vicinity of the above luminous article at a treating temperature lower than the glass transition temperature or the heat resistance temperature representing the long term heat resistance of the above plastic substrate. The above method can improve the performance capability for sealing the luminous article, without detriment to characteristics of the plastic substrate.

Description

 P2005 / 005647

 1 Description Method of manufacturing light-emitting panel

 The present invention relates to a method for manufacturing a light-emitting panel, and more particularly to a method for manufacturing an organic EL panel (organic electorescent luminescent panel) using a plastic substrate. Background art

 In an organic EL panel, an organic EL element including a light-emitting body made of an organic material is formed on a substrate. Since the organic EL element deteriorates when exposed to moisture, oxygen, and the like, a protective film (passivation film) is formed to cover and seal the entire organic EL element that should be shielded from the outside air. In general, the protective film includes a dense film having high blocking performance against the permeation of impurities to improve sealing performance. If the protective film has a defect, the impurities transmitted through the defect promote oxidation of the constituent materials of the device, and deteriorate the organic EL device. This kind of deterioration causes the generation and expansion of dark spots (non-light emitting points) in the light emitting surface, shortens the life of the organic EL element, and lowers the yield.

In addition, as organic EL panels have become thinner and lighter, film-shaped flexible plastic substrates have been used instead of glass substrates. Film-shaped plastic substrates have more impurities than glass substrates. And easily deteriorate the characteristics of the organic EL element. Therefore, in order to prevent the transmission of impurities from the plastic substrate side, a barrier film is formed on the surface of the plastic substrate. Note that technologies related to protective films and barrier films P2005 / 005647

 The two techniques are disclosed in, for example, JP-A-2001-307873 and JP-A-2002-134268.

 The protective film, the barrier film, and the organic EL element are formed by either a wet process using a solvent or a dry process without using a solvent. The wet process includes a spin coating method, a blade coating method, a roll coating method, a dive method and various printing methods, and the dry process includes a CVD method (chemical vapor deposition method) or a PVD method (physical vapor phase method). Growth method).

 In the wet process, first, a solvent containing a precursor is applied to the underlying surface to form a precursor film. Next, a thin film is formed by, for example, heating the precursor film. Here, if the heating temperature for heating the precursor film is low, the solvent does not evaporate sufficiently and remains in the thin film, so that the solvent remaining in the thin film changes into a volatile gas and reaches the organic EL element. There is a problem that the characteristics of the organic EL element are deteriorated. To avoid this problem, the heating temperature should be set higher.1S If this heating temperature is set higher than the heat resistance temperature of the plastic substrate, the characteristics of the plastic substrate, for example, optical characteristics such as light transmittance, or flexibility or Deterioration of mechanical properties such as tensile strength causes problems. Disclosure of the invention

 A main object of the present invention is to provide a method for manufacturing a light emitting panel capable of improving sealing performance for a light emitting body such as an organic EL element without deteriorating the characteristics of a plastic substrate.

According to a first aspect of the present invention, there is provided a method of manufacturing a light-emitting panel including a light-emitting body formed on a plastic substrate, the method comprising: (a) lowering a glass transition temperature of the plastic substrate. Forming the luminous body at a low processing temperature; and (b) forming a structure near the luminous body at a processing temperature lower than the glass transition temperature of the plastic substrate. It is characterized by including. According to a second aspect of the present invention, there is provided a method of manufacturing a light-emitting panel including a light-emitting body formed on a plastic substrate, comprising: (a) a processing temperature lower than a heat-resistant temperature indicating long-term heat resistance of the plastic substrate (B) forming a structure in the vicinity of the luminous body at a processing temperature lower than a heat-resistant temperature indicating the long-term heat resistance of the plastic substrate; It is characterized by including.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing a cross section of an organic EL panel according to an embodiment of the present invention. FIG. 2 is a sectional view schematically showing an example of the organic functional layer.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments according to the present invention will be described.

 As shown in FIG. 1, the organic EL panel (light emitting panel) 1 includes a plastic substrate 10 and a barrier film 11 formed on the plastic substrate 10. Next, a first electrode layer 12, an insulating film 13, an organic functional layer 14, and a second electrode layer 15 are formed in this order.

The organic EL element (luminous body) 17 includes a first electrode layer 12, an organic functional layer 14, and a second electrode layer 15. Further, the organic EL element 17 is sealed with a protective film (passivation film) 16. The organic EL panel 1 includes, in addition to the components shown in FIG. 1, a color filter, a plurality of partitions for dividing the organic EL element 17, or a driving circuit including a TFT (thin film transistor) and a capacitor. Dare, may include components. In this specification, a Noria film 11, an insulating film 13, a protective film 16, and a plurality of partitions formed on the plastic substrate 10 and near the organic EL element 17 are referred to as "structures". Shall be referred to.

 The plastic substrate 10 has a film shape and has flexibility. The present invention focuses on the glass transition temperature (Tg), which indicates short-term heat resistance, and the UL standard heat-resistant temperature, which indicates long-term heat resistance, as standards for the heat resistance of the plastic substrate 10. UL standards are a US agency

(Underwriters Laboratories Inc.). In this UL standard, “rated temperature” refers to the physical properties of a test piece (bow I tensile strength or Izod strength) when the test piece is exposed to the air at a certain temperature for 100,000 hours at a constant temperature. It is defined as the temperature at which the mechanical properties such as impact strength or electrical properties) are reduced by half from the initial values. In this specification, as the “heat resistant temperature” of the plastic substrate 10, the rated temperature of the mechanical characteristics of UL746B standard, that is, RTI (Relative Thermal Index) is adopted.

As a constituent material of such a plastic substrate 10, any of a crystalline plastic and an amorphous plastic can be used. Non-crystalline plastic materials include acrylic resins such as PMMA (polyethyl methacrylate; Tg = 100-105 ° C), PC (polycarbonate; Tg = 143-150 ° C), PES (polyether sulfone; Tg = 230 ° C), PAr (polyarylate; Tg = 190 ° C), PEI (polyethenoleimide; Tg = 215-220 ° C) or PI (polyimide; Tg = 323-340 ° C) Examples of the crystalline plastic material include PBT (polybutylene terephthalate; Tg = 66 ° C.), PET (polyethylene terephthalate; Tg = 73 to 78 ° C.), and PPS (polyphenylene sulfide; Tg = 85.C). ), PEEK (polyetheretherketone; Tg = 140 ° C) or PEN (polyethylene naphthalate; Tg = 121 ° C). If the plastic substrate 10 requires translucency, use an amorphous plastic material.If the plastic substrate 10 does not require translucency, use a relatively heat-resistant crystalline plastic material. Good. 05 005647

 5 Regarding the heat resistance temperature, for example, RTI is about 105 ° C for a PET sample with a thickness of 25 μπι, and RTI is about 120 ° C for a sample of PET with a thickness of 50 μm. For the PEN sample above, the RTI is about 160 ° C, for the 7.6 μm to 25 μm PI sample, the RTI is 200 ° C, and for the 50 μm PI sample, the RTI is 230 °. (: RTI of about 180 ° C for a 50 m thick PES sample, 170 ° C for a 50 µm thick ΡΕΙ sample, and 130 RTI for a 50 µm thick PAr sample. RTI is about 160 ° C for PPS samples with a thickness of 12 ° m or more at ° C.

 As described later, an organic EL element 17 and structures such as a barrier film 11, an insulating film 13, and a protective film 16 are formed in the element forming region on the plastic substrate 10. The organic EL element 17 and the structure are formed at a processing temperature in a temperature range lower than the glass transition temperature (Tg) or the heat resistance temperature (RTI) of the constituent material of the plastic substrate 10, and One feature is that the organic EL element 17 is formed from a material whose characteristics do not deteriorate at a processing temperature in a temperature range. This reliably prevents the optical or mechanical properties of the film-shaped plastic substrate 10 from irreversibly changing in the process of forming the organic EL element 17 and the structure, thereby improving the yield and improving the quality of the organic EL element. Panel 1 can be provided. Here, from the viewpoint of preventing the characteristic deterioration of the plastic substrate 10, when an amorphous plastic force such as the spc force is also configured, the glass transition temperature (Tg) of the constituent material of the plastic substrate 10 is low. While it is preferable to form the organic EL element 17 and the structure at a processing temperature in the temperature range, if the plastic substrate 10 is made of a crystalline plastic such as PET, the structure of the plastic substrate 10 It is preferable to form the organic EL element 17 and the structure at a processing temperature in a temperature range lower than the heat resistance temperature (RTI) of the material.

Further, for example, the plastic substrate 10 may be formed by depositing a non-crystalline ester-based resin on the surface of a PET substrate which is a crystalline plastic. Thus, when the plastic substrate 10 is made of a crystalline plastic and an amorphous plastic, the smaller of the heat resistance temperature (RTI) of the crystalline plastic and the glass transition temperature (Tg) of the amorphous plastic. One The organic EL element 17 and the structure are preferably formed at a processing temperature in a temperature range lower than the above temperature.

The barrier film 11 has a function of preventing impurities such as moisture and oxygen from permeating into the organic EL element 17 of the plastic substrate 10. The NOR film 11 can be formed by a dry process such as a CVD method or a PVD method, or a wet process such as a spin coating method and a dive method. Examples of the insulating material of the ceramic film 11 include metal oxides such as silicon oxide (Si〇 ₂ ), metal nitrides such as silicon nitride, metal nitride oxides such as silicon nitride (SiON), and the like. An organic insulating material such as a polyimide resin may be used. For example, a silicon nitride film is formed on the surface of the plastic substrate 10 by a CVD method, and then a photocurable resin is applied on the silicon nitride film by a spin coating method and cured to form a resin film. By doing so, the ceramic film 11 can be formed. This resin film is a silicon nitride film due to mechanical stress.

It has a function to prevent the occurrence of cracks.

 When the Noria film 11 is formed by a wet process, first, a solution obtained by dissolving a precursor in a solvent (solvent) is applied on a plastic substrate 10 to form a precursor film. Next, by heating the precursor film, the solvent in the precursor film evaporates, and the barrier film 11 is formed. As described above, when the solvent remains in the Noria film 11, it changes into a volatile gas and deteriorates the characteristics of the organic EL element 17. In order to avoid this, it is preferable to set the temperature at which the precursor film is heated to be higher than the boiling point of the solvent.

Solvents used in the wet process include PGME (Propylene Glycol Monomethyl Ether Acetate), PGMEA (Propylene Glycol Monomethyl Ether Acetate), PGMEA (Propylene Glycol Monomethyl Ether Acetate), Ethylene Lactate, and DMAc (DMAc). N, N-Dimethylacetamide; N, N-Dimethylacetamide), MEK (Methyl Ethyl Ketone), ΜΙΒΚ (Methyl Isobutyl Ketone), IPA (Isopropyl Alcohol), Ethanol , Toluene, benzene, benzene, dichlorobenzene, chlorophonolem, tetralin, xylene, Nore, dichloromethane, _y- mouth ratataton, butylcellosolve, cyclohexane, ΝΜΡ (Ν-methyl-2-pyrrolidone), dimethylsulfoxide, cyclohexanone, dioxane ぴ HF (tetrahydrofuran), etc. More than one species can be used. Regarding the boiling point of the solvent, for example, the boiling point of toluene is 110.4 to 110.6 ° C, the boiling point of benzene is 80.1 ° C, the boiling point of dichlorobenzene is 172 to 173 ° C, and the boiling point of · 26 ° C, tetralin has a boiling point of 206.5-207.6 ° C, xylene has a boiling point of 139 ° C, aesole has a boiling point of 153.8-155 ° C, and dichloromethane has a boiling point of 39.8-40. 2 ° C, γ-butyrolactone has a boiling point of 198 to 208 ° C, butyl cellosolve has a boiling point of 168.4 to 172 ° C, and cyclohexane has a boiling point of 80.7 to 81.4 ° C, NMP (N-methyl (2-pyrrolidone) has a boiling point of 197 to 202 ° C, dimethyl sulfoxide has a boiling point of 189 ° C, cyclohexanone has a boiling point of 115.6 to 155.7 ° C, and dioxane has a boiling point of 101 to: L01. ° C, THF (tetrahydrofuran) has a boiling point of 64 to 66 ° C, PGME has a boiling point of 119 to 120 ° C, PGMEA has a boiling point of 145.8 ° C, and Echinoleate lactate has a boiling point of 154.5 ° C, DMAc Boiling point of 166-16.1 ° C, MEK boiling point . 79. 57~79 6 ° C, the boiling point of the MIBK is 116. 7 ~ 118 ° C,; . ^ Eighth boiling 82-82 4 ° C, ethanol boiling, is § ⁸ 3 ° C..

 The first electrode layer 12 can be formed by depositing a conductive material on the nori film 11 by an evaporation method or a CVD method and patterning the conductive material. Further, it is desirable that the first electrode layer 12 be subjected to a surface treatment such as organic cleaning and UV-zone cleaning. When the first electrode layer 12 is an anode, it is preferable that the first electrode layer 12 be a conductive material having a large work function in terms of hole injection into the organic functional layer 14. As the conductive material, for example, a transparent conductive material such as ITO (Indium Tin Oxide), ΙΖΟ (Indium Zinc Oxide) or tin oxide, or a conductive material such as polythiophene or polyaniline is used. Molecular materials.

Further, insulating films 13 and 13 are formed so as to cover the edges at both ends of the first electrode layer 12. The insulating films 13 and 13 have a function of being used as a mask in the step of forming the organic functional layer 14 or of preventing a short circuit between the first electrode layer 12 and the second electrode layer 15. Insulating film The layers 13 and 13 may be formed by depositing and lettering an insulating material by a CVD method or a vacuum evaporation method, or may be used in the step of forming the barrier film 11 by a wet process. The insulating films 13 and 13 can be formed by using a solution obtained by dissolving the precursor in the same solvent as the solvent.

 An organic functional layer 14 is formed on the first electrode layer 12 and the insulating films 13 and 13. FIG. 2 is a cross-sectional view schematically showing an example of the organic functional layer 14. The organic functional layer 14 is formed by sequentially forming a hole injection layer 20, a hole transport layer 21, a light emitting layer 22, and an electron injection layer 23. When holes are injected from the first electrode layer 12 by the applied voltage and electrons are injected from the second electrode layer 15, the holes and electrons move in the organic functional layer 14 and have a predetermined probability in the light emitting layer 22. Rejoin. The energy of the recombination is released through one or both of the singlet excited state and the triplet excited state of the organic molecules constituting the light-emitting layer 22, and emits fluorescence or phosphorescence, or both fluorescence and phosphorescence. Will be done.

The layers 20 to 23 constituting the organic functional layer 14 are made of a low molecular material or a polymer material, and the layer made of the low molecular material is formed by a dry process such as a vacuum evaporation method. It is generally formed by a wet process such as spin coating, blade coating, divebing, or printing. When the organic functional layer 14 is formed by a wet process such as a spin coating method, toluene, benzene, chlorobenzene, dichloromethane, chlorophonolem, tetralin, xylene, anisolone, dichloromethane, _γ- petit ratataton, butyl cell One or more selected solvents such as Solve, cyclohexane, ΝΜΡ (Ν-methyl-2-pyrrolidone), dimethylsulfoxide, cyclohexanone, dioxane or THF (tetrahydrofuran) are used as a solvent, and A solution obtained by dissolving the precursor can be used as a coating liquid.

When the organic functional layer 14 is formed by a wet process, a precursor film is formed by applying a solvent obtained by dissolving a precursor in a solvent, and the precursor film is heated to evaporate the solvent. The temperature at which the precursor film is heated is preferably set higher than the boiling point of the solvent so that the solvent does not remain in the organic functional layer 14 and deteriorate the characteristics of the organic EL element 17. The constituent materials of the hole injection layer 20 and the hole transport layer 21 include copper phthalocyanine and TPD (a dimer of tripheninoleamine), or polythiophene and polyaniline. The light-emitting materials that constitute the light-emitting layer 22 include Al (aluminoquinolinol complex), ΒΑ1 (almiquinolinol complex), DPVBi (distyrylarylene derivative), EM2 (oxadiazol derivative), and BMA—nT (oligothiophene). Derivatives; n is a positive integer) and the like. The constituent material of the electron injection layer 23 is, for example, Li ₂ O (lithium oxide).

 Note that the organic functional layer 14 is a four-layer element, but instead, the organic functional layer 14 may be a single-layer element including only the light-emitting layer 22, or the light-emitting layer 22, the hole transport layer 21, and the hole. A three-layer device including the injection layer 20 may be used.

 After the formation of the organic functional layer 14, a second electrode layer 15 is formed by depositing and patterning a conductive material on the organic functional layer 14 by a vacuum evaporation method or the like. When the second electrode layer 15 is a cathode, it is preferable that the second electrode layer 15 be made of a conductive material having a small work function and being relatively stable chemically from the viewpoint of electron injection into the organic functional layer 14. Examples of the conductive material include an MgAg alloy, magnesium, aluminum, and an aluminum alloy. Although the electrode patterns of the first electrode layer 12 and the second electrode layer 15 are not explicitly shown in the figure, the first electrode layer 12 and the second electrode layer 15 may be formed in a strip shape so as to be orthogonal to each other. Good.

After the formation of the organic EL element 17, a protective film 16 is formed so as to cover the organic EL element 17 by a dry process or a wet process. Examples of the insulating material forming the protective film 16 include metals such as aluminum, magnesium and copper, metal oxides such as silicon oxide (Si〇 ₂ ) and magnesium oxide, metal nitrides such as silicon nitride, and the like. Examples include metal nitrides such as silicon nitride oxide (SiON) and organic insulating materials such as polyimide resin.

Here, when the protective film 16 is formed by a wet process, a precursor film is formed by applying a solution obtained by dissolving the precursor in a solvent, and the precursor film is heated to evaporate the solvent. Let The The temperature at which the precursor film is heated is preferably set to be higher than the boiling point of the solvent so that the solvent does not remain in the protective film 16 and deteriorate the characteristics of the organic EL element 17.

 As described above, according to the organic EL panel 1, the organic EL element 17 and the barrier film are processed at a processing temperature in a temperature range lower than the glass transition temperature (Tg) or the heat resistance temperature (RTI) of the constituent material of the plastic substrate 10. The organic EL element 17 is formed from a material that does not deteriorate its characteristics at a processing temperature within this temperature range, and the temperature range is determined by the boiling point of the solvent used in the wet process. Is also set to a higher range. For this reason, it is possible to provide the organic EL panel 1 having high sealing performance and good light emission characteristics without deteriorating the mechanical characteristics and optical characteristics of the plastic substrate 10.

 This application is based on Japanese Patent Application No. 2004-103602, and is incorporated in the present disclosure.

Claims

範 囲 Claims  1. A method for manufacturing a light-emitting panel including a light-emitting body formed on a plastic substrate, the method comprising: forming the light-emitting body at a processing temperature lower than a glass transition temperature of the plastic substrate;  (b) forming a structure near the light-emitting body at a processing temperature lower than the glass transition temperature of the plastic substrate.  2. The method for manufacturing a light-emitting panel according to claim 1, wherein in the steps (a) and (b), the processing temperature is lower than a heat resistance temperature indicating a long-term heat resistance of the plastic substrate by a range of V. A method for manufacturing a light-emitting panel, comprising:  3. A method of manufacturing a light-emitting panel including a light-emitting body formed on a plastic substrate, (a) a step of forming the luminous body under a processing temperature lower than a heat resistance temperature indicating long-term heat resistance of the plastic substrate,  (b) forming a structure near the light-emitting body at a processing temperature lower than a heat-resistant temperature indicating the long-term heat resistance of the plastic substrate.  4.The method for manufacturing a light-emitting panel according to claim 2 or claim 3, wherein the heat-resistant temperature is set when the plastic substrate is exposed to the air at a constant temperature for 100,000 hours. A method for manufacturing a light-emitting panel, wherein the temperature is a temperature at which the mechanical strength of a plastic substrate is reduced by half. 5. The method for manufacturing a light emitting panel according to claim 4, wherein the heat-resistant temperature is specified according to UL746B standard. 6. The method for manufacturing a light emitting panel according to any one of claims 1 to 5, wherein the step (a) comprises forming one or more films by a wet process using a solvent. A method for producing a light-emitting panel, comprising a step, wherein the processing temperature is further in a range higher than a boiling point of the solvent. 7. The method for manufacturing a light-emitting panel according to any one of claims 1 to 5, wherein in the step (b), one or more films are formed by a wet process using a solvent. A method for producing a light-emitting panel, comprising a step, wherein the processing temperature is further in a range higher than a boiling point of the solvent.  8. The method for manufacturing a light emitting panel according to any one of claims 1 to 7, wherein in the step (b), a protective film covering the light emitting body is formed as the structure. A method for manufacturing a light-emitting panel, comprising the steps of:  9. The method for manufacturing a light-emitting panel according to any one of claims 1 to 8, wherein the step (b) is performed before the step (a). Forming a barrier film interposed between the substrate and a barrier film for preventing transmission of impurities as the structure.  10. The method for manufacturing a light-emitting panel according to any one of claims 1 to 9, wherein the light-emitting body is an organic electorescent luminescent element. .