JP2014118308A - Translucent substrate, method for producing the same and surface light emitting element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a translucent substrate that solves the problem of distortion of the translucent substrate and is excellent in light extraction efficiency of light emitting elements such as organic EL and the like formed on the translucent substrate, to provide a method for producing the translucent substrate and to provide a surface light emitting element such as organic EL and the like formed on the substrate.SOLUTION: The translucent substrate has an alkali-free glass substrate and a high refractive material layer containing at least one kind of glass material having a coefficient of linear expansion larger than a coefficient of linear expansion (CTE) of the alkali-free glass substrate on the alkali-free glass substrate and comprising at least one kind of glass material having a coefficient of linear expansion smaller than the CTEon the alkali-free glass substrate. The method for producing a translucent substrate produces the translucent substrate as mentioned above.

Description

  The present invention relates to a light-transmitting substrate excellent in light extraction efficiency of a light-emitting element such as an organic EL formed on the light-transmitting substrate, a manufacturing method thereof, and a surface light-emitting element such as an organic EL formed on the substrate.

  As a substrate used for a display to which an organic electroluminescence element is applied, in particular, in an active drive system of a TFT type (thin film transistor), when the substrate contains an alkali metal oxide or the like, a metal or oxide is present on the substrate surface. In a thin film forming process for forming a thin film or the like, there is a problem that alkali metal ions diffuse into the thin film and the film characteristics are significantly deteriorated. Therefore, an alkali-free glass substrate that does not contain an alkali oxide having excellent chemical resistance, heat resistance, high electrical insulation, and high elastic modulus is preferably used.

  Furthermore, in recent years, as displays have been remarkably spread and demands for a large area are increasing, a non-alkali glass substrate used is also required to have a large area.

  In Patent Document 1, unevenness is provided on the surface of a translucent glass substrate serving as a base, and a high refractive material layer obtained by melting a glass frit material is formed on the uneven surface, thereby improving the extraction efficiency. The translucent substrate thus formed can efficiently extract both the thin-film waveguide light and the substrate waveguide light in the organic electroluminescence light-emitting device, and has excellent industrial mass productivity. It has been reported that the benefits are great.

  In Patent Document 2, a high-refractive material layer obtained by melting a glass frit material is formed on a light-transmitting glass substrate serving as a base, and a scattering material having a different refractive index is transmitted through the high-refractive material layer. By forming a high-refractive material layer with a varying content distribution in the depth direction from the optical glass substrate to the electrode and adding a light scattering function, both thin-film guided light and substrate-guided light are efficiently extracted. There have been reports of improved light extraction efficiency.

In Patent Document 1, if the difference between the coefficient of linear expansion (CTE) of the glass frit material used and the CTE of the translucent glass substrate is large, distortion may occur and breakage such as cracks may occur in the high refractive index material layer. There is a description that the CTE difference between them is preferably smaller than 10 × 10 ⁻⁷ . However, as a result of the study by the present inventors, when a high refractive index material layer is formed on a large area non-alkali glass substrate (CTE = 32 × 10 ⁻⁷ / ° C.), a CTE difference of about 10 × 10 ^−7. It was found that a sufficient distortion level could not be secured even when using a glass frit having a thickness (the target of the distortion level is a warp amount of 1 mm or less when the substrate size is 500 mm). Further, there is generally no glass frit material having a CTE of the same level as that of an alkali-free glass substrate, and there is a big problem for application to a large area display.

In Patent Document 2, the CTE of the glass frit material used is 50 × 10 ⁻⁷ / ° C. or higher, preferably 70 × 10 ⁻⁷ / ° C. or higher, more preferably 95 × 10 ⁻⁷ / ° C. or higher, due to distortion. Has been. However, assuming a non-alkali glass substrate for large area display applications, the difference in CTE will be large, resulting in substrate distortion and the occurrence of cracks in the high refractive material layer. There are major challenges.

  A translucent substrate having a structure in which a highly refractive material layer obtained by melting a glass frit material on an alkali-free glass substrate is formed, and a glass frit material as a raw material for the alkali-free glass substrate and the highly refractive material layer is generally used Further, since it is difficult to combine CTE due to the difference in material composition, a concave substrate as shown in FIG. 9A or a convex substrate warp as shown in FIG. 9B occurs. FIG. 9C is a graph showing the relationship between the amount of warpage of a translucent substrate in which a high refractive material layer is formed on an alkali-free glass substrate and the CTE of the glass frit material used for the high refractive material layer. . The warpage amount in the graph is obtained by calculating the warpage amount shown in FIG. 9A or 9B from the surface shape profile obtained by scanning the translucent substrate by 10 mm.

  FIG. 10 is a graph showing a result of simulating the warpage amount and the warpage amount when the area is increased, and it can be seen that there is a problem that the substrate warpage amount increases as the area is increased.

JP 2012-133944 A International Publication No. 2009/060916

  In any of the above methods, in a translucent substrate in which a highly refractive material layer is formed on an alkali-free glass substrate, the substrate is strained (amount of substrate warpage) so that the light extraction efficiency of the surface light emitting element can be improved and the area can be increased. A method for solving this problem has not been proposed yet.

  In view of the above-described problems, an object of the present invention is to solve the problem of distortion of a light-transmitting substrate and provide a light-transmitting substrate having excellent light extraction efficiency.

The translucent substrate according to an embodiment of the present invention contains an alkali-free glass substrate, and on the alkali-free glass substrate, at least one glass material larger than the linear expansion coefficient CTE _glass of the alkali-free glass substrate, And it has the high refractive material layer containing at least 1 sort (s) of glass material smaller than said CTE _glass, It is characterized by the above-mentioned.

  The translucent substrate according to an embodiment of the present invention is characterized in that, in the above-described configuration, the interface between the alkali-free glass substrate and the high refractive material layer is uneven.

  The translucent substrate according to an embodiment of the present invention is characterized in that, in the configuration, the high refractive material layer is made of a scattering material having a refractive index different from that of the glass material and the glass material. Yes.

Further, the translucent substrate according to an embodiment of the present invention, in the structure, the alkali-free glass substrate, and the CTE _Glass greater comprises at least one glass material layer, the CTE _Glass smaller at least one It is characterized by having a high refractive material layer composed of two or more layers including a layer made of a glass material.

  Moreover, the translucent substrate according to one embodiment of the present invention is characterized in that, in the above configuration, the interface between the alkali-free glass substrate and the high refractive material layer is uneven.

  In the translucent substrate according to an embodiment of the present invention, in the configuration, at least one of the two layers of the high refractive material layer has a refractive index different from that of the glass material and the glass material. It consists of a scattering material.

The translucent substrate according to an embodiment of the present invention is characterized in that, in the above configuration, crystallized glass is included in a high refractive material layer containing a glass material having a CTE smaller than the CTE _glass . .

  The translucent substrate according to an embodiment of the present invention is characterized in that, in the above configuration, the high refractive material layer has a thickness of 40 μm or less.

  Moreover, the organic electroluminescent element by one Embodiment of this invention is characterized by using the translucent board | substrate in any one which has the said structure.

In addition, a method for manufacturing a light-transmitting substrate according to an embodiment of the present invention includes a non-alkali glass substrate on which at least one glass frit material larger than the CTE _{glass and} at least one glass frit material smaller than the CTE _glass. A paste is prepared by mixing, the paste is applied, the paste is dried, and the dried paste is baked to form a high refractive material layer.

In addition, a method for manufacturing a light-transmitting substrate according to an embodiment of the present invention includes a paste A or a non-alkali glass substrate containing at least one glass frit material larger than the linear expansion coefficient CTE _glass of the non-alkali glass substrate. Applying any one paste of paste B containing at least one glass frit material smaller than the CTE _glass , drying the paste, firing the dried film obtained by the dried paste, A step of forming a fired film (high refractive index material layer), and the first application and drying of the paste A and the paste B on the high refractive material layer formed by the first application / drying / firing step. A paste that has not been applied in the drying / firing step is applied onto the first fired film (high refractive index material layer), the paste is dried, and the dry It is characterized by forming a stacked high refractive material layer by calcining the resulting dried film by paste.

In addition, a method for manufacturing a light-transmitting substrate according to an embodiment of the present invention includes a paste A or a non-alkali glass substrate containing at least one glass frit material larger than the linear expansion coefficient CTE _glass of the non-alkali glass substrate. A first coating / drying step of applying and drying any one of pastes B containing at least one glass frit material smaller than the CTE _glass, and a dry film formed by the first coating / drying step On top of this, the second application / drying step of applying the paste that has not been applied in the first application / drying step of the paste A and the paste B, and the laminated type formed by the second application / drying step A laminated high refractive material layer is formed by firing the dry film.

  According to the present invention, it is possible to improve the amount of substrate warpage caused by the CTE difference between the glass frit material used for the high refractive material layer and the non-alkali glass substrate, so that the substrate distortion is small and the area can be increased. A light-transmitting substrate having excellent light extraction efficiency can be provided.

(A) is the schematic of the organic EL element 100 which concerns on Embodiment 1, (b) is the schematic of the organic EL element 200 which concerns on Embodiment 2, (c) is the organic EL element which concerns on Embodiment 3. FIG. FIG. (A) is the schematic of the organic EL element 400 which concerns on Embodiment 4, (b) is the schematic of the organic EL element 500 which concerns on Embodiment 5, (c) is the organic EL element which concerns on Embodiment 6. FIG. FIG. 6D is a schematic diagram of an organic EL element 700 according to the seventh embodiment. (A) is the schematic of the organic EL element 800 which concerns on Embodiment 8, (b) is the schematic of the organic EL element 900 which concerns on Embodiment 9, (c) is the organic EL element which concerns on Embodiment 10. FIG. FIG. (A) is the schematic of the organic EL element 1100 which concerns on Example 11, (b) is the schematic of the organic EL element 1200 which concerns on Example 12. FIG. (A) thru | or (h) is the schematic which shows the manufacturing process of the high refractive material layer 120 of 4th to 10th Embodiment, Example 11 and Example 12 in order. (A) thru | or (f) is the schematic which shows the manufacturing process of the high refractive material layer 120 of 4th to 10th Embodiment, Example 11 and Example 12 in order. (A) is a glass frit material A having two kinds of glass frit materials (CTE (CTE _Low ) lower than the CTE of the alkali-free glass substrate) used for forming the high refractive material layer 120 of the first to third embodiments. The relationship between the value defined by the following formula (1) (CTE calculated value) and the warpage amount from the blending ratio of the glass frit material B having a CTE (CTE _High ) higher than the CTE of the alkali-free glass substrate It is a graph which shows. CTE calculation value = CTE _Low × combination ratio A (%) + CTE _High × combination ratio (100-A) (%) (1) (b) is the high refractive material layer of the fourth to twelfth embodiments. The film thickness ratio of the high refractive material layer 120A formed by melting the glass frit material A and the high refractive material layer 120B formed by melting the glass frit material B is a value defined by the following formula (2): It is a graph which shows the relationship with the amount of curvature. Film thickness ratio (%) = 120A film thickness (μm) / 120B film thickness (μm) × 100 (2) (A) is a schematic sectional drawing which shows the general structure of a bottom emission type organic EL element, (b) is a schematic sectional drawing which shows the general structure of a top emission type organic EL element. (A) And (b) is the schematic of the concave and convex board | substrate curvature which generate | occur | produces in the translucent board | substrate which formed the highly refractive material layer obtained by fuse | melting glass frit material on an alkali free glass board | substrate. (C) shows the amount of warpage of the translucent substrate in which the high refractive material layer is formed on the alkali-free glass substrate (CTE = 32 × 10 ⁻⁷ ) and the CTE of the glass frit material used for the high refractive material layer. It is the graph which showed the relationship. The warpage amount in the graph is obtained by calculating the warpage amount shown in FIG. 9A or 9B from the surface shape profile obtained by scanning the translucent substrate by 10 mm. It is a graph which shows the result of having simulated the relationship between the amount of curvature mentioned above and the amount of curvature when it enlarged.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

(General configuration of OLED)
First, a general configuration of an OLED will be described with reference to FIGS. 8 (a) and 8 (b). FIG. 8A is an explanatory diagram showing a general cross-sectional configuration of a bottom emission type OLED, and FIG. 8B is an explanatory diagram showing a general cross sectional configuration of a top emission type OLED.

  As shown in FIG. 8A, the bottom emission type OLED 10 includes a transparent conductive film such as ITO formed on a substrate 11 made of glass or the like by a sputtering method, a resistance heating vapor deposition method, or the like. One electrode 12 and N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine (hereinafter abbreviated as NPD) formed on the first electrode 12 by the resistance heating vapor deposition method or the like. And the like, a light emitting layer 14 made of 8-hydroxyquinoline Al μmin μm (hereinafter abbreviated as Alq3) formed on the hole transport layer 13 by a resistance heating vapor deposition method, and the like, and a light emitting layer 14. Tris (8-quinolinolato) aluminum, tris (4-methyl-8-quinolinolato) aluminum, bis (2-methyl-8-quinolino) formed above Lat) -4-phenylphenolate-aluminum, electron transport layer 15 made of a metal complex such as bis [2- [2-hydroxyphenyl] benzoxazolate] zinc, and resistance heating vapor deposition method on electron transport layer 15 And a second electrode 16 made of a reflective metal film made of aluminum or the like. When a DC voltage or a DC current is applied with the first electrode 12 of the bottom emission type OLED 10 having the above configuration as a positive electrode and the second electrode 16 as a negative electrode, the first electrode 12 passes through the hole transport layer 13. Then, holes are injected into the light emitting layer 14, and electrons are injected from the second electrode 16 into the light emitting layer 14 through the electron transport layer 15. In the light-emitting layer 14, recombination of holes and electrons occurs, and a light emission phenomenon occurs when excitons generated thereby shift from the excited state to the ground state.

  FIG. 8B is a cross-sectional view showing the structure of the top emission type OLED 20. In the case of the top emission type OLED 20, the bottom emission type OLED 10 in that the first electrode 12 is made of a highly reflective metal layer such as aluminum and the second electrode 16 is made of a transparent conductive film such as ITO. The structure is different. As described above, in the case of a top emission type OLED, the first electrode 12 is generally composed of a reflective metal and the second electrode 16 is composed of a thin film metal or a transparent conductive material.

  Examples of the transparent conductive material include ITO (Indium Tin Oxide), tin oxide, zinc oxide, IZO (Indium Zinc Oxide), AZO (Aluminum-doped Zinc Oxide), and GZO (Gallium-doped Zinc Oxide). be able to. In addition to the inorganic conductive film, an organic conductive film such as a polyparaphenylene vinylene derivative, a polyfluorene derivative, a polythiophene derivative, or the like can be used as the conductive substance constituting the transparent electrode, or the inorganic conductive film and the A composite film in which an organic conductive film is multilayered can be used.

  The present invention is applicable to both the bottom emission type OLED and the top emission type OLED.

[First Embodiment]
First, the configuration of the OLED according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1A is an explanatory diagram showing a cross-sectional configuration of the OLED 100 according to the first embodiment of the present invention.

  As shown in FIG. 1A, the OLED 100 according to the first embodiment of the present invention is a bottom emission type, and includes an alkali-free glass substrate 110, a high refractive material layer 120, a transparent electrode 130 as a positive electrode, The organic light emitting layer 150 and the cathode 180 are mainly provided.

  The OLED 100 has a structure in which a concavo-convex surface 111 is formed on the surface of an alkali-free glass substrate 110, and the concavo-convex surface 111 is flattened by a high refractive material layer 120 (surface that contacts the transparent electrode 130). doing. The uneven surface 111 formed at the interface between the alkali-free glass substrate 110 and the high refractive material layer 120 has a function of scattering light incident from the transparent electrode 130 side. Hereinafter, each component of the OLED 100 will be described in detail.

<Non-alkali glass substrate 110>
As a substrate generally applicable to OLED, for example, glass materials such as alkali-free glass, soda lime glass, high strain point glass (PD200, etc.), for example, polyethersulfone (PES), polyacrylate (PAR), Polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polyimide (PI), polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate Examples thereof include transparent plastic materials having insulating properties such as (CAP). In recent years, as a substrate used for a display using OLED, especially in a TFT type (thin film transistor) active drive system, when the substrate contains an alkali metal oxide or the like, a metal or oxide thin film or the like is formed on the substrate surface. In the thin film formation process for forming the film, there is a problem that alkali metal ions diffuse into the thin film and the film characteristics are remarkably deteriorated.

  In addition, for the purpose of preventing the permeability of mobile ions such as alkali metals, a means for protecting the substrate surface with a passivation film such as silicon nitride or silicon oxide to ensure reliability is also known. There is a problem of cost burden due to an increase in processes. Therefore, in the present invention, an alkali-free glass substrate not containing an alkali oxide having excellent chemical resistance, heat resistance, high electrical insulation, and high elastic modulus is used.

<Uneven surface 111>
The concavo-convex surface 111 is a surface having random concavo-convex such that light generated in the organic light emitting layer 150 passes through the transparent electrode 130 and is incident on the non-alkali glass substrate 110 to disturb the refraction angle of incident light. is there. In the present invention, after a dry film made of a glass frit material and a resin is formed on the concavo-convex surface 111, the high refractive material layer 120 is formed by removing the resin in a baking step and melting the glass frit. For this reason, it is preferable to use a glass frit material having a melting point lower than that of the alkali-free glass substrate.

  The degree of unevenness of the uneven surface 111 is not particularly limited, but is preferably 0.7 μm or more and 5 μm or less in terms of the average surface roughness Ra specified in JIS B 0601-2001. When Ra is smaller than 0.7 μm, the light extraction effect may not be sufficient. Moreover, when Ra exceeds 5 μm, the extraction efficiency tends to decrease. The reason is considered as follows. As in the present embodiment, when light extraction is to be used to increase the extraction efficiency, the light passes through the scattering layer (the region where the uneven surface 111 is present) in the OLED 100 several times. As a result, light can be extracted to the outside of the OLED 100. Considering such a mechanism, if Ra is large, the high refractive material layer 120 inevitably becomes thick in order to flatten the surface of the high refractive material layer 120 (the surface in contact with the transparent electrode 130). This is because when the thickness of the high refractive material layer 120 is too thick, loss due to light absorption in the high refractive material layer 120 cannot be ignored. In this respect, the glass frit used as the material of the high refractive material layer 120 used in the present invention is made of a metal oxide and has an extremely small extinction coefficient k in the visible light region. The attenuation of is negligibly small.

<Uneven shape of uneven surface 111>
The uneven shape of the uneven surface 111 in the present embodiment may be the random shape described above, or may be a regular shape having a uniform structural unit such as a lens shape or a pyramid shape. . There are no particular restrictions on the specific shape or size of such a lens structure or pyramid structure, which is sufficiently large for the wavelength range of the generated light and capable of exhibiting a light condensing effect, which is larger than the pixel size. What is necessary is just to have a small structural unit. The pixel size (pixel size) of a general display is about 100 to 600 μm, and each size of RGB is 1/3 of the size, so it is about 30 to 200 μm. Therefore, as a specific shape of the uneven surface 111 in this modification, a lens shape (substantially hemispherical shape) or a pyramid shape (substantially four) having a structural unit with a size (uneven height) of several μm to several tens μm. Pyramid shape).

  Further, the thickness of the high refractive material layer 120 is not particularly limited as long as it is sufficient to flatten the uneven surface 111 of the alkali-free glass substrate 110, but according to the study by the present inventors, It is preferably 1.3 times or more the maximum height of the uneven surface 111 of the alkali-free glass substrate 110. That is, if the uneven surface 111 has a lens structure, and the structural unit of the lens is a hemispherical shape with a diameter of 10 μm, the maximum height of the uneven surface 111 of the alkali-free glass substrate 110 is 5 μm. The preferred thickness of the material layer 120 is 6.5 μm or more. If the structural unit of the lens is a hemispherical shape having a diameter of 80 μm, the preferred thickness of the high refractive material layer 120 is 52 μm or more.

<High refractive material layer 120>
The high refractive material layer 120 is disposed between the alkali-free glass substrate 110 and the transparent electrode 130 described above, and has a refractive index equal to or higher than the refractive index of the alkali-free glass substrate 110, and is incident from the transparent electrode 130 side. It has an uneven surface 111 that scatters light, and a surface in contact with the transparent electrode 130 is flat.

  When creating a surface light emitting device such as an OLED, the substrate is required to have high smoothness. This is because many surface light-emitting elements are composed of thin films (several tens of nanometers to several micrometers), and if there are irregularities on the surface of the substrate, current leakage occurs and the elements cannot be driven stably. Therefore, in this embodiment, in order to flatten the uneven surface 111 formed on the alkali-free glass substrate 110, the uneven surface formed on the surface of the alkali-free glass substrate 110 using a glass paste containing glass frit. After forming a dry film made of a glass frit material and a resin on 111, the surface in contact with the transparent electrode 130 is flattened by providing a high refractive material layer 120 in which the resin is removed and the glass frit is melted in a baking process. . Various materials for flattening the unevenness of the substrate surface have been proposed, such as SOG material and CVD film, but it is not possible to form a film thickness that can flatten the unevenness having a large roughness. There are many problems in practical use, such as the need for highly expensive and sophisticated equipment for film formation, which takes time. According to the study by the present inventors, when an SOG material is used, the maximum film thickness that can be formed is at most about 1 to 2 μm, and even a SiN film formed using the CVD method can be practically formed. The film thickness is several μm. The structure (unevenness) for adjusting the refraction angle of the incident light to the substrate, such as light scattering and condensing, is a structure larger than the wavelength of the incident light (unevenness having a roughness larger than the wavelength of the incident light) If the SOG material or the CVD method is used, it is impossible to achieve flattening of the uneven surface.

  In contrast, in the method of forming a high refractive material layer using the glass frit of the present embodiment, the glass frit is made of a high boiling point solvent such as terpineol or butyl carbitol acetate and a thickening agent such as ethyl cellulose or acrylic resin. By simply applying a glass paste prepared by mixing with a binder resin onto the alkali-free glass substrate 110, drying and baking, the uneven surface 111 can be easily flattened, and a sufficient film thickness can be obtained. It is possible to form the high refractive material layer 120. The glass paste for forming the highly refractive material layer 120 is a paste-like composition containing glass frit, a solvent, and a resin. Hereinafter, each component of the glass paste according to this embodiment will be described. .

<Glass frit>
First, the glass frit used in the present embodiment has a thermal characteristic such that a transparent glass layer (high refractive material layer 120) can be formed at a temperature at which the alkali-free glass substrate 110 is not distorted or distorted. Need to be. When the alkali-free glass substrate 110 is subjected to a temperature of 650 ° C. or higher, distortion and strain are generated, which is not preferable. In order to form the high refractive material layer 120 at 650 ° C. or lower, the glass transition temperature (Tg) of the glass frit is preferably 630 ° C. or lower.

  The material forming the high refractive material layer 120, that is, the refractive index of the glass frit needs to be higher than the refractive index of the alkali-free glass substrate 110. The refractive index of the glass frit is preferably about the same as that of the transparent electrode 130 (for example, formed of ITO). The refractive index of a substrate of a surface light emitting element such as a general OLED is about 1.5, and the refractive index of a transparent conductive film (transparent electrode) is about 2. If the refractive index of the high-refractive material layer 120 is about the same as that of the alkali-free glass substrate 110, the reflection at the interface with the transparent electrode 130 is the same as when there is no uneven surface 111 and the high-refractive material layer 120, It cannot be desired to improve the light extraction efficiency. Specifically, in the OLED 100 according to the present embodiment, the refractive index of the high refractive material layer 120 is preferably about 1.7 to 2.5.

Examples of the glass frit component having a low glass transition temperature and a high refractive index as described above are, for example, 1 selected from P ₂ O ₅ , SiO ₂ , B ₂ O ₃ , Ge ₂ O, and TeO ₂ as a network former. It contains seeds or two or more kinds of components, and as a high refractive index component, TiO ₂ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , ZnO, BaO, PbO, Sb ₂ O ₃ can be used. High refractive index glass containing one or more components selected from two or more components can be used.

In Embodiment 1, the high refractive material layer 120 includes at least one glass frit material A smaller than the CTE _{glass of the} alkali-free glass substrate 110 and at least one glass frit material B larger than the CTE _glass. These glass frit materials are mixed and melted to form a desired high refractive material layer.

In the high refractive material layer 120 in the first embodiment, the CTE (CTE _low , CTE _high ) and blending ratio (A%, B%) of the glass frit materials A and B to be used are defined as follows. Yes.
CTE _glass ≧ CTE _low × glass frit material A blending ratio A (%) + CTE _high × glass frit material B blending ratio B (= 100−A) (%) ≧ CTE _{glass −10} × 10 ^−7. 1)

Further, as the glass frit component in this embodiment, in addition to the above components, alkali metal oxides, alkaline earth metal oxides, fluorides, etc. are required for the refractive index in order to adjust the characteristics of the glass. You may use in the range which does not impair the physical property made. Specific examples of the glass frit component system include, for example, B ₂ O ₃ —ZnO—La ₂ O ₃ system, P ₂ O ₅ —B ₂ O ₃ —R ′ ₂ O—R ″ O—TiO ₂ —Nb _2. O ₅ —WO ₃ —Bi ₂ O ₃ system, TeO ₂ —ZnO system, B ₂ O ₃ —Bi ₂ O ₃ system, SiO ₂ —Bi ₂ O ₃ system, SiO ₂ —ZnO system, B ₂ O ₃ —ZnO System, P ₂ O ₅ —ZnO system, etc. Here, R ′ represents an alkali metal element, and R ″ represents an alkaline earth metal element.

<Solvent>
The solvent used for the glass paste of the present embodiment is not particularly limited as long as it is an organic solvent. However, considering the production process, if the drying rate is too fast, the organic solvent is dried during production, and solids are precipitated, which is not preferable. From such a viewpoint, the organic solvent used in the glass paste of the present embodiment is preferably a solvent having a boiling point of 150 ° C. or higher, more preferably 180 ° C. or higher. As such a solvent, for example, a terpene solvent (terpineol) Etc.) and carbitol solvents (butyl carbitol, butyl carbitol acetate) and the like can be used.

<Resin>
The resin used for the glass paste of the present embodiment is not particularly limited as long as it exhibits an appropriate viscosity for applying the paste, but the resin disappears at a temperature lower than the glass transition temperature of the glass frit. Is preferred. This is because if the resin is not baked and removed at a temperature lower than the temperature at which the glass frit exhibits fluidity, the resin gasifies at the temperature at which the glass is baked, causing bubbles inside the glass. Specific examples that can be suitably used as such a resin include ethyl cellulose and nitrocellulose as cellulosic resins, and acrylic resin and methacrylic resin as acrylic resins.

<Other additives>
If necessary, an additive for the purpose of improving the dispersibility of the glass frit and the resin and adjusting the rheology may be added to the glass paste of the present embodiment. As such an additive, for example, adjustment of viscosity suitable for processes such as slit coating, polymers added for the purpose of improving dispersibility of glass frit, thickeners added for the purpose of rheology adjustment, Examples thereof include a dispersant added for the purpose of preparing a glass paste with good dispersibility. Examples of the polymer include acrylic polymers. Examples of the thickener include cellulose resins such as ethyl cellulose, polyoxyalkylene resins such as polyethylene glycol, and the like. Examples of the dispersant include dispersants such as polyvalent carboxylic acids and ammonium salts thereof. Examples of the polyvalent carboxylic acid include lower to higher aliphatic polyvalent carboxylic acids, and these may form an ammonium salt such as a tetrabutylammonium salt. Specifically, for example, the HIPLAAD series manufactured by Enomoto Kasei Co., Ltd., the Disperbyk series manufactured by Big Chemie, and the like can be mentioned. In addition, it is preferable that content of the above additives is 3 mass parts or less with respect to 100 mass parts of glass pastes, for example.

<Film thickness>
The film thickness of the high refractive material layer 120 is not particularly limited as long as it is sufficient to flatten the uneven surface 111 of the alkali-free glass substrate 110. It is preferable that the glass substrate 110 has a thickness not less than 30 times and not more than 40 times the average roughness Ra. The absolute range of the film thickness of the high refractive material layer 120 is preferably about 3 μm to 100 μm, and more preferably 3 μm to 40 μm. This is because the maximum height Rz of the concavo-convex surface 111 formed by sandblasting or wet etching is approximately 10 to 20 times Ra.

  From the same meaning as described above, the thickness of the highly refractive material layer 120 is 1.3 times or more the maximum roughness Rz (described in JIS B 0601-2001) of the uneven surface 111 of the alkali-free glass substrate 110. Is preferred. This is because if it is less than 1.3 times Rz, the high refractive material layer 120 that provides sufficient reliability with respect to the driving stability described above cannot be obtained.

  As described above, it is impossible to easily form a flattened film having the above thickness with an SOG material (sol-gel material) or a vacuum process (CVD or the like). On the other hand, methods of obtaining a thick planarized film with an organic material such as a polymer are conceivable. However, these methods have sufficient heat resistance (300 ° C.) for forming a transparent conductive film (transparent electrode) such as ITO. In addition, as described above, the high refractive index layer 120 is required to have a high refractive index (preferably 2 or more), but such a refractive index is realized with an organic material. There can be no material that can. That is, unless the glass paste containing the glass frit in the present embodiment is used, the high refractive material layer 120 having the above thickness cannot be easily formed.

  The film thickness of the high refractive material layer 120 can be confirmed by measuring the film thickness after firing, but the non-alkali glass substrate 110 has a concavo-convex surface 111 (concavo-convex structure). The film thickness varies depending on the position. Therefore, the film thickness of the high refractive material layer 120 in this embodiment is the film thickness from the deepest part of the uneven surface 111 to the uppermost part of the high refractive material layer 120, but the uneven surface 111 has random unevenness. If it is a shape, it may be difficult to determine the deepest part even by analyzing the cross-sectional shape. In such a case, the film thickness is measured for 10 or more arbitrarily selected sites, There is no problem even if the maximum thickness portion is considered as the film thickness.

<Smoothness of the interface between the high refractive material layer 120 and the transparent electrode 130>
Although it repeats above, when producing surface emitting elements, such as OLED, high smoothness is calculated | required by a board | substrate. This is because many surface light-emitting elements are composed of thin films (several tens of nanometers to several micrometers), and if there are irregularities on the surface of the substrate, current leakage occurs and the elements cannot be driven stably. In the present invention, the smoothness of the interface between the high refractive material layer 120 and the transparent electrode 130 is not particularly limited, but according to the study by the present inventors, Ra is 30 nm or less, preferably 1 nm or less.

<Transparent electrode 130>
The transparent electrode 130 is a layer that functions as an anode of the OLED 100, and has a conductivity, and a transparent material is used to extract light out of the OLED 100. Specifically, as a material for forming the transparent electrode 130, a transparent oxide semiconductor, particularly ITO, IZO (Indium Zinc Oxide), ZnO, In ₂ O ₃ or the like is preferably used.

<Organic light emitting layer 150>
The organic light emitting layer 150 includes at least a light emitting layer (also referred to as “EL layer” for short). The organic light emitting layer 150 may include a hole injection layer and an electron injection layer. When the organic light emitting layer 150 includes both the hole transport layer and the hole injection layer, the hole injection layer is disposed closer to the transparent electrode 130 than the hole transport layer. Further, the EL layer included in the organic light emitting layer 150 is disposed on the side farther from the transparent electrode 130 than the hole transport layer.

  As a hole transport material for forming the hole transport layer, for example, known materials such as α-NPD (NPB), TPD, TACP, and triphenyl tetramer can be used. Moreover, as a hole injection material which forms a hole injection layer, well-known materials, such as polyaniline, a polypyrrole, copper phthalocyanine (CuPc), PEDOT: PSS, can be used, for example.

  The organic light emitting layer 150 may include one or more of red, green and blue light emitting layers.

  Examples of the material for forming the red light emitting layer include tetraphenylnaphthacene (rubrene), tris (1-phenylisoquinoline) iridium (III) (Ir (piq) 3), and bis (2-benzo [b] thiophene. 2-yl-pyridine) (acetylacetonate) iridium (III) (Ir (btp) 2 (acac)), tris (dibenzoylmethane) phenanthroline europium (III) (Eu (dbm) 3 (phen)), tris [4,4′-di-tert-butyl- (2,2 ′)-bipyridine] ruthenium (III) complex (Ru (dtb-bpy) 3 * 2 (PF6)), DCM1, DCM2, Eu (thenoyltrifluoro) Acetone) 3 (Eu (TTA) 3, butyl-6- (1,1,7,7-tetramethyldurori) Le-9-enyl) -4H- pyran) (DCJTB) can be used like, Besides, polyfluorene-based polymer, a polymeric light emitting material, such as polyvinyl-based polymer can be used.

  Examples of the material for forming the green light-emitting layer include Alq3, 3- (2-benzothiazolyl) -7- (diethylamino) coumarin (Coumarin6), 2,3,6,7-tetrahydro-1,1,7, 7, -Tetramethyl-1H, 5H, 11H-10- (2-benzothiazolyl) quinolidine- [9,9a, 1gh] coumarin (C545T), N, N′-dimethyl-quinacridone (DMQA), tris (2-phenyl) Pyridine) iridium (III) (Ir (ppy) 3) can be used, and in addition, polymer light-emitting substances such as polyfluorene-based polymers and polyvinyl-based polymers can also be used.

  Examples of the material for forming the blue light emitting layer include oxadiazole dimer dye (Bis-DAPOXP), spiro compounds (Spiro-DPVBi, Spiro-6P), triarylamine compounds, bis (styryl) amine (DPVBi, DSA), 4,4′-bis (9-ethyl-3-carbazovinylene) -1,1′-biphenyl (BCzVBi), perylene, 2,5,8,11-tetra-tert-butylperylene (TPBe), 9H -Carbazole-3,3 '-(1,4-phenylene-di-2,1-ethene-diyl) bis [9-ethyl- (9C)] (BCzVB), 4,4-bis [4- (di- p-tolylamino) styryl] biphenyl (DPAVBi), 4- (di-p-tolylamino) -4 ′-[(di-p-tolylamino) styri Ru] stilbene (DPAVB), 4,4′-bis [4- (diphenylamino) styryl] biphenyl (BDAVBi), bis (3,5-difluoro-2- (2-pyridyl) phenyl- (2-carboxypyridyl) Iridium III (FIrPic) or the like can be used, and in addition, a polymer light-emitting substance such as a polyfluorene polymer or a polyvinyl polymer can be used.

As described above, the organic light emitting layer 150 may include an electron transport layer and an electron injection layer in order from the side close to the cathode 180. As an electron transport material for forming the electron transport layer, known materials such as an oxazole derivative (PBD, OXO-7), a triazole derivative, a boron derivative, a silole derivative, and Alq3 can be used. As the electron injecting material, for _example, be used LiF, Li 2 O, CaO, CsO, known materials such as CsF _2.

<Cathode 180>
A material for forming the cathode 180 is a metal, particularly a metal having a small work function. Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, and compounds thereof can be used.

[Method of Manufacturing First Embodiment (OLED 100)]
The configuration of the OLED 100 according to the present embodiment has been described in detail above. Subsequently, a method for manufacturing the OLED 100 according to the present embodiment having the above-described configuration will be described in detail.

The manufacturing method of the translucent board | substrate which concerns on this embodiment used as the board | substrate of OLED100 contains a surface roughening process, an application | coating process, a drying process, and a baking process. The surface roughening step is a step of forming the uneven surface 111 on the surface of the alkali-free glass substrate 110. In the coating process, at least one kind of glass frit material having a refractive index higher than that of the alkali-free glass substrate 110 on the surface of the alkali-free glass substrate 110 on which the uneven surface 111 is formed and smaller than the CTE _{glass of the} alkali-free glass substrate 110. This is a step of applying a glass paste containing A, at least one glass frit material B larger than CTE _glass , a solvent, and a resin. A drying process is a process of drying the glass paste apply | coated to the alkali free glass substrate 110, volatilizing a solvent, and forming a dry film | membrane. The baking step is a step of baking the dried film obtained in the drying step to eliminate and remove the resin and melt the glass frit to form the high refractive material layer 120 on the alkali-free glass substrate 110. Hereinafter, a method for manufacturing the OLED 100 including these steps will be described.

(Surface roughening process)
In the surface roughening step, light generated in the organic light emitting layer 150 passes through the transparent electrode 130 by a method such as a sand blast method, a wet etching method (frost method) or a press method on the surface of the alkali-free glass substrate 110. Random uneven surfaces 111 that cause disturbance in the refraction angle of incident light when entering the alkali glass substrate 110 are formed. The degree of unevenness of the uneven surface 111 formed at this time is not particularly limited as described above, but is preferably 0.7 μm or more and 5 μm or less in terms of average surface roughness Ra.

  Moreover, when forming the uneven surface 111 having the above-described uniform structural unit, the shape of the uneven surface 111 on the surface of the alkali-free glass substrate 110 has a uniform structural unit such as a lens structure or a pyramid structure. It is formed to be uneven. Such a lens structure or pyramid structure can be formed using, for example, a mold thermal transfer method, a photolithography / wet etching method, laser processing, polishing with a grindstone, or the like.

(Preparation of glass paste)
Next, a glass paste containing the glass frit as described above, a solvent, and a resin is prepared. As a method for preparing this glass paste, a glass frit, a (binder) resin, and other components are dissolved and mixed in a solvent, and then kneaded with a roll mill or the like to produce a paste in which the glass frit is dispersed. The mixing ratio of the glass frit, the solvent and the resin may be, for example, about 50 to 80% by mass of the glass frit, 10 to 40% by mass of the solvent, and about 1 to 10% by mass of the resin. As described above, in consideration of the melting point of the alkali-free glass substrate 110, it is preferable to carry out the drying process and the baking process described later at a temperature of 650 ° C. or lower. For this purpose, the glass transition temperature of the glass frit is It is preferable that it is 630 degrees C or less.

(Coating process)
Next, the prepared glass paste is coated (applied) on the surface of the uneven surface 111 of the alkali-free glass substrate 110. The method for applying the glass paste is not particularly limited, and for example, a known method such as bar coating, doctor blade, slit coating, or die coating can be used.

(Drying process)
Next, the alkali-free glass substrate 110 having the uneven surface 111 coated with glass paste is transferred to a hot air dryer or the like to remove the solvent and form a dry film. As described above, the drying temperature at this time is preferably 650 ° C. or lower so that the alkali-free glass substrate 110 does not melt. More preferably, it is 100 degreeC or more and 200 degrees C or less.

(Baking process)
After the drying step, the non-alkali glass substrate 110 having the dried film from which the solvent has been removed is transferred to a firing furnace and fired at a temperature not lower than the glass transition temperature Tg and not higher than the softening temperature Ts of the glass frit (binder) resin. Is removed by burning and the glass frit is melted. Further, the high refractive material layer 120 is formed on the surface of the alkali-free glass substrate 110 by baking at a temperature not lower than the softening temperature Ts of the glass frit (preferably not higher than 650 ° C.) in a baking furnace.

(Formation of transparent electrode 130, organic thin film layer including organic light emitting layer 150, and cathode 180)
Next, ITO, IZO, ZnO, In ₂ O ₃ or the like is formed on the alkali-free glass substrate 110 whose surface is planarized by the high refractive material layer 120 by using a method such as spin coating or sputtering. A transparent electrode 130 is formed. Furthermore, after forming a hole transport layer and an organic light emitting layer by vapor-depositing a hole transport material or a light emitting material on the transparent electrode 130, an electron transport layer is formed to form the organic light emitting layer 150, and the electron An OLED 100 can be manufactured by depositing a metal such as Ag, Mg, or Al on the transport layer to form the cathode 180 (see FIG. 1A). The hole transport layer, the organic light emitting layer, the electron transport layer, and the cathode 180 forming the organic light emitting layer 150 may be formed by vacuum deposition, casting methods (spin casting method, dipping method, etc.), ink jet methods, printing methods. A known method such as a method (typographic printing, gravure printing, offset printing, screen printing, etc.) can be used.

[Use of First Embodiment OLED 100]
The translucent substrate used in the OLED 100 of the present embodiment has irregularities (surface roughness) that are equal to or greater than the wavelength order, and thereby scatters light incident on the translucent substrate, so that all wavelengths of light are scattered. It can be taken out efficiently. Therefore, the OLED 100 can be suitably used for a white OLED or the like, and can also be applied to a lighting fixture or a backlight for a display device that requires high efficiency.

[Second Embodiment]
[Configuration of OLED 200]
FIG.1 (b) is explanatory drawing which shows the cross-sectional structure of OLED200 which concerns on the 2nd Embodiment of this invention.

  As shown in FIG.1 (b), OLED200 which concerns on the 2nd Embodiment of this invention is a bottom emission type, Comprising: The alkali-free glass substrate 110, the high refractive material layer 120, the transparent electrode 130 as a positive electrode, The structure mainly including the organic light emitting layer 150 and the cathode 180 is common to the first embodiment.

  In the second embodiment, a filler 125 is mixed as a scattering material having a refractive index different from the refractive index of the glass frit that is a base material of the high refractive material layer in the high refractive material layer 120, and an alkali-free glass substrate. An uneven surface is not formed on 110, and the interface between the alkali-free glass substrate 110 and the high refractive material layer 120 is flat, which is different from the first embodiment.

[Third Embodiment]
[Configuration of OLED 300]
FIG.1 (c) is explanatory drawing which shows the cross-sectional structure of OLED300 which concerns on the 3rd Embodiment of this invention.

  As shown in FIG.1 (c), OLED200 which concerns on the 3rd Embodiment of this invention is a bottom emission type, Comprising: The alkali free glass substrate 110, the high refractive material layer 120, the transparent electrode 130 as a positive electrode, The structure mainly including the organic light emitting layer 150 and the cathode and 180 is common to the first embodiment.

  The third embodiment is that the filler 125 is mixed as a scattering material having a refractive index different from the refractive index of the glass frit that is the base material of the high refractive material layer in the high refractive material layer 120. Is different. In the third embodiment, the concavo-convex surface is formed on the alkali-free glass substrate 110 as in the first embodiment.

Note that two types of glass frit materials (a glass frit material A having a CTE (CTE _Low ) lower than the CTE of an alkali-free glass substrate) and an alkali-free glass are used for forming the highly refractive material layer 120 of the first to third embodiments. Experimental results showing the relationship between the value defined by the above formula (1) (CTE calculated value) and the amount of warpage from the blending ratio of the glass frit material B having a CTE (CTE _High ) higher than the CTE of the substrate Is shown in FIG.

[Fourth Embodiment]
[Configuration of OLED 400]
FIG. 2A is an explanatory diagram showing a cross-sectional configuration of an OLED 400 according to the fourth embodiment of the present invention.

  As shown in FIG. 2A, the OLED 400 according to the fourth embodiment of the present invention is a bottom emission type, and includes an alkali-free glass substrate 110, a highly refractive material layer 120, a transparent electrode 130 as a positive electrode, The structure mainly including the organic light emitting layer 150 and 180 is common to the first embodiment.

  The fourth embodiment is that the high refractive material layer 120 is composed of two layers, a high refractive material layer 120A including the glass frit material A and a high refractive material layer 120B including the glass frit material B. Is different. The high refractive material layer 120A and the high refractive material layer 120B are manufactured by sequentially performing the steps shown in FIGS. 5A to 5H or FIGS. 6A to 6F. Can do.

One of the glass frit materials A and B is a glass frit material having a CTE (CTE _low ) smaller than the CTE _{glass of the} alkali-free glass substrate 110, and the other is larger than the CTE _{glass of the} alkali-free glass substrate 110. It consists of a glass frit material with CTE (CTE _high ).

Further, in the manufacturing method of FIG. 5, it is required that cracks due to substrate warpage do not occur when the first highly refractive material layer is formed. For this reason, the difference between the CTE (CTE _low or CTE _high ) of the glass frit material as the base material and the CTE _glass of the non-alkali glass substrate is preferably 50 × 10 ⁻⁷ or less, more preferably 30 × 10 ⁻⁷ or less. It is.

The film thickness ratio of the high refractive material layer 120A and the high refractive material layer 120B in Embodiment 4 is defined by the equation (2).
0.5 ≦ high refractive material layer thickness (CTE _low ) / high refractive material layer thickness (CTE _high ) ≦ 2.0 (2)

[Fifth Embodiment]
[Configuration of OLED 500]
FIG. 2B is an explanatory diagram showing a cross-sectional configuration of an OLED 500 according to the fifth embodiment of the present invention.

  As shown in FIG. 2B, the OLED 500 according to the fifth embodiment of the present invention is a bottom emission type, and includes a non-alkali glass substrate 110, a high refractive material layer 120A including a glass frit material A, and a glass frit material. In a structure mainly including a high refractive material layer 120 including two high refractive material layers 120B containing B, a transparent electrode 130 as a positive electrode, an organic light emitting layer 150, and a cathode 180, the fourth embodiment Common with form.

  In the fifth embodiment, a filler 125 is mixed in the high refractive material layer 120B as a scattering material having a refractive index different from the refractive index of the glass frit that is a base material of the high refractive material layer. It differs from the embodiment.

[Sixth Embodiment]
[Configuration of OLED 600]
FIG. 2C is an explanatory diagram showing a cross-sectional configuration of an OLED 600 according to the sixth embodiment of the present invention.

In the sixth embodiment, the filler 125 is mixed in the high refractive material layer 120A, while the filler 125 is not mixed in the high refractive material layer 120B. It has the same configuration as.
[Seventh Embodiment]
[Configuration of OLED 700]
FIG. 2D is an explanatory diagram showing a cross-sectional configuration of an OLED 700 according to the seventh embodiment of the present invention.

  The seventh embodiment has the same configuration as that of the fourth to sixth embodiments except that the filler 125 is mixed in both the high refractive material layer 120A and the high refractive material layer 120B.

[Eighth Embodiment]
[Configuration of OLED 800]
FIG. 3A is an explanatory diagram showing a cross-sectional configuration of an OLED 800 according to the eighth embodiment of the present invention. An OLED 800 according to the eighth embodiment corresponds to the OLED 500 according to the fifth embodiment, and has the same structure as the OLED 500 except that an uneven surface is not formed on the alkali-free glass substrate 110.

[Ninth Embodiment]
[Configuration of OLED 900]
FIG. 3B is an explanatory view showing a cross-sectional configuration of an OLED 900 according to the ninth embodiment of the present invention, and the OLED 900 is the OLED 600 except that the uneven surface is not formed on the alkali-free glass substrate 110. Has the same structure.

[Tenth embodiment]
[Configuration of OLED1000]
FIG. 3C is an explanatory diagram showing a cross-sectional configuration of the OLED 1000 according to the tenth embodiment of the present invention. The OLED 1000 has the OLED 700 except that an uneven surface is not formed on the alkali-free glass substrate 110. Has the same structure.

[Crystallized glass]
Further, in the first to tenth embodiments, high refraction made of crystallized glass is used instead of the high refraction material layer whose base material is a glass frit material having a CTE (CTE _low ) smaller than the CTE _{glass of the} alkali-free glass substrate. A material layer can be used.

The crystallized glass is a ceramic-like polycrystalline body obtained by reheating glass under controlled conditions to uniformly precipitate and grow a large number of fine crystals. First, a large number of nuclei are uniformly formed in the glass, and a large number of fine crystals are uniformly grown based on the nuclei, whereby a polycrystal is formed. Typical crystallized glass is Li ₂ O—Al ₂ O ₃ —SiO ₂ , Na ₂ O—Al ₂ O ₃ —SiO ₂ , MgO—Al ₂ O ₃ —SiO ₂ , Na ₂ O—CaO—MgO—. Examples thereof include SiO ₂ , PbO—ZnO—B ₂ O ₃ , and ZnO—B ₂ O ₃ —SiO ₂ .

[Manufacturing Method of Fourth to Tenth Embodiments]
The high-refractive material layer 120A and the high-refractive material layer 120B according to the fourth to tenth embodiments perform the steps shown in FIGS. 5A to 5F or FIGS. 6A to 6F. It can manufacture by performing sequentially.

  First, the first manufacturing method (FIG. 5) will be described. First, a glass paste A containing a glass frit material A, a solvent, and a resin is prepared on an alkali-free glass substrate 110, and the glass paste A is applied so as to have a predetermined film thickness. Is removed to obtain a dry film. Next, the obtained dried film is baked to burn and remove the resin, and the glass paste A is melted to obtain a first highly refractive material layer. Thereafter, a glass paste B containing a glass frit material B, a solvent, and a resin is prepared, and the glass paste B is applied on the first highly refractive material layer so as to have a predetermined film thickness, followed by drying. A dry film is obtained by removing the solvent in the process. This is baked, the resin is burned off and the glass paste B is melted, and the second high refractive material layer is formed on the first high refractive material layer, so that the high refractive material is formed on the high refractive material layer 120A. The high refractive material layer 120 having a structure in which the layer 120B is laminated is manufactured.

  Next, the second manufacturing method (FIG. 6) will be described. First, a glass paste A containing a glass frit material A, a solvent, and a resin is prepared on an alkali-free glass substrate 110, and the glass paste A is applied so as to have a predetermined film thickness. Is removed to obtain a dry film. Next, a glass paste B containing a glass frit material B, a solvent, and a resin is prepared, and the glass paste B is applied on the dry film so as to have a predetermined film thickness. By removing, a dry film laminated on the alkali-free glass substrate 110 is obtained. The high refractive material layer 120 having a structure in which the high refractive material layer 120B is laminated on the high refractive material layer 120A is manufactured by baking this, removing the resin by burning, and melting the glass paste A and the glass paste B. The

FIG. 7B shows experimental results showing the relationship between the thickness ratio (3) of the high refractive material layer 120A and the high refractive material layer 120B in Embodiments 4 to 10 and the amount of warpage. .
Film thickness ratio (%) = high refractive material layer thickness (CTE _low ) / high refractive material layer thickness (CTE _high ) (3)

  The high-refractive material layer 120 in the fourth to tenth embodiments changes more slowly than the high-refractive material layer 120 in the first to third embodiments in the range where the amount of warpage (μm) is ± 1.0 μm. Therefore, it is a preferable structure because the amount of warpage can be controlled more easily.

[Example]
Examples 1 to 12 of the present invention will be described below. Examples 1 to 10 have a configuration corresponding to each of Embodiments 1 to 10, respectively. Examples 11 to 12 correspond to a light-transmitting substrate formed using crystallized glass. The “translucent substrate” in Examples 1 to 12 below means a substrate composed of the high refractive material layer 120 and the alkali-free glass substrate 110 in FIGS. 1 to 3.

Example 1
Glass frit material prepared by mixing ZnTE glass frit with CTE = 10.5 × 10 ⁻⁷ / ° C. and ZnO glass frit with CTE = 41 × 10 ⁻⁷ / ° C. in an arbitrary ratio; 45 g, ethyl cellulose STD45 (Dow Chemical Company) 3 g, terpineol; 36.4 g, butyl carbitol acetate; 15.6 g were dissolved and mixed, and then kneaded with a three-roll mill to prepare a glass paste.

  Concavity and convexity non-alkali glass obtained by spraying # 800 alumina powder under the condition of 0.5 kPa on an alkali-free glass substrate (EagleXG; manufactured by Corning) having a thickness of 0.7 mm and a size of 50 × 50 mm. It is coated on a substrate using a doctor blade, the solvent is removed with a 120 ° C. hot air dryer, transferred to a baking furnace, baked at 400 ° C. for 20 minutes, the resin is removed, baked at 630 ° C. for 30 minutes, and translucent. A substrate was created.

(Example 2)
Glass frit material in which CTE = 10.5 × 10 ⁻⁷ / ° C. ZnO glass frit and CTE = 41 × 10 ⁻⁷ / ° C. ZnO glass frit are mixed at an arbitrary ratio; 45 g, eucryptite as a filler material Crystal (D50 = 2 μm); 6.8 g, D50 ethylcellulose STD45 (manufactured by Dow Chemical); 3 g, terpineol; 36.4 g, butyl carbitol acetate; 15.6 g were dissolved and mixed, and then kneaded by a three-roll mill. A filler-containing glass paste was prepared.

  After applying the above filler-containing glass paste onto a non-alkali glass substrate (EagleXG; manufactured by Corning) having a thickness of 0.7 mm and a size of 50 × 50 mm using a doctor blade, the solvent was removed with a 120 ° C. hot air dryer. Then, after transferring to a baking furnace and baking at 400 ° C. for 20 minutes to remove the resin, baking was carried out at 630 ° C. for 30 minutes to prepare a translucent substrate.

(Example 3)
In the same manner as in Example 2, a filler-containing glass paste was prepared. Thereafter, a highly refractive material layer was formed on the alkali-free glass substrate with unevenness similar to that in Example 1 in the same manner as in Example 1 to prepare a translucent substrate.

Example 4
CTE = 10.5 × 10 ⁻⁷ / ° C. ZnO glass frit material; 45 g, ethyl cellulose STD45 (manufactured by Dow Chemical); 3 g, terpineol; 36.4 g, butyl carbitol acetate; 15.6 g A glass paste A was prepared by kneading with a three-roll mill.

A glass paste B was prepared in the same manner as described above except that 45 g of ZnO-based glass frit material with CTE = 41 × 10 ⁻⁷ / ° C. was used.

  No unevenness obtained by spraying the above glass paste A onto a non-alkali glass substrate (Eagle XG; manufactured by Corning) having a thickness of 0.7 mm and a size of 50 × 50 mm under the condition of 0.5 kPa. It apply | coated using the doctor blade on the alkali glass board | substrate, after removing a solvent with a 120 degreeC hot-air dryer, it moved to the baking furnace, baked at 400 degreeC for 20 minutes, baked at 630 degreeC for 30 minutes after removing resin. On the high refractive material layer thus formed, glass paste B was applied in the same manner using a doctor blade, the solvent was removed with a 120 ° C. hot air dryer, transferred to a baking furnace, and the mixture was transferred to 400 ° C. for 20 minutes. After baking and removing the resin, baking was performed at 630 ° C. for 30 minutes to prepare a light-transmitting substrate on which a high refractive material layer was laminated.

(Example 5)
ZnO glass frit material with CTE = 10.5 × 10 ⁻⁷ / ° C .; 45 g, eucryptite crystal (D50 = 2 μm) as filler material; 6.8 g, ethylcellulose STD45 (manufactured by Dow Chemical Co.); 3 g, terpineol; 36.4 g and butyl carbitol acetate; 15.6 g were dissolved and mixed, and then kneaded with a three-roll mill to prepare a filler-containing glass paste A.

Also, after dissolving and mixing ZnO glass frit material of CTE = 41 × 10 ⁻⁷ / ° C .; 45 g, ethyl cellulose STD45 (manufactured by Dow Chemical Co.); 3 g, terpineol; 36.4 g, butyl carbitol acetate; 15.6 g A glass paste B was prepared by kneading with a three-roll mill.

  These glass frit dispersion pastes were used in the same manner as in Example 4 to prepare a translucent substrate on which a high refractive material layer was laminated.

(Example 6)
CTE = 10.5 × 10 ⁻⁷ / ° C. ZnO glass frit material; 45 g, ethyl cellulose STD45 (manufactured by Dow Chemical); 3 g, terpineol; 36.4 g, butyl carbitol acetate; 15.6 g A glass paste A was prepared by kneading with a three-roll mill.

In addition, CTE = 41 × 10 ⁻⁷ / ° C. ZnO-based glass frit material; 45 g, eucryptite crystal (D50 = 2 μm) as filler material; 6.8 g, ethyl cellulose STD45 (manufactured by Dow Chemical Co.); 3 g, terpineol; 36.4 g and butyl carbitol acetate; 15.6 g were dissolved and mixed, and then kneaded with a three-roll mill to prepare filler-containing glass paste B.

  These glass frit dispersion pastes were used in the same manner as in Example 4 to prepare a translucent substrate on which a high refractive material layer was laminated.

(Example 7)
In the same manner as in Example 5, a filler-containing glass paste A was prepared. Further, a filler-containing glass paste B was prepared in the same manner as in Example 6.
Using these glass pastes in the same manner as in Example 4, a translucent substrate on which a high refractive material layer was laminated was prepared.

(Example 8)
In the same manner as in Example 5, filler-containing glass paste A and glass paste B were prepared.

  The filler-containing glass paste A is applied onto a non-alkali glass substrate (Eagle XG; manufactured by Corning) having a thickness of 0.7 mm and a size of 50 × 50 mm using a doctor blade, and the solvent is removed with a hot air dryer at 120 ° C. Then, it moved to the baking furnace, baked for 20 minutes at 400 degreeC, removed the resin, and baked for 30 minutes at 630 degreeC. On the high refractive material layer thus formed, glass paste B was applied in the same manner using a doctor blade, the solvent was removed with a 120 ° C. hot air dryer, transferred to a baking furnace, and the mixture was transferred to 400 ° C. for 20 minutes. After baking and removing the resin, baking was performed at 630 ° C. for 30 minutes to prepare a light-transmitting substrate on which a high refractive material layer was laminated.

Example 9
In the same manner as in Example 6, glass paste A and filler-containing glass paste B were prepared. Using these glass pastes in the same manner as in Example 8, a translucent substrate on which a high refractive material layer was laminated was prepared.

(Example 10)
In the same manner as in Example 7, filler-containing glass paste A and filler-containing glass paste B were prepared.
Using these glass pastes in the same manner as in Example 8, a translucent substrate on which a high refractive material layer was laminated was prepared.

(Example 11)
ZnO glass frit material made of crystallized glass; 45 g, ethyl cellulose STD45 (manufactured by Dow Chemical Co.); 3 g, terpineol; 36.4 g, butyl carbitol acetate; 15.6 g were dissolved and mixed, and then kneaded by a three-roll mill. A glass paste A was prepared.

Also, after dissolving and mixing ZnO glass frit material of CTE = 41 × 10 ⁻⁷ / ° C .; 45 g, ethyl cellulose STD45 (manufactured by Dow Chemical Co.); 3 g, terpineol; 36.4 g, butyl carbitol acetate; 15.6 g A glass paste B was prepared by kneading with a three-roll mill.

  Using these glass pastes, a translucent substrate 1100 on which a high refractive material layer 120 was laminated was produced in the same manner as in Example 8 (FIG. 4A).

(Example 12)
CTE = 41 × 10 ⁻⁷ / ° C. ZnO-based glass frit material; 45 g, ethyl cellulose STD45 (manufactured by Dow Chemical); 3 g, terpineol; 36.4 g, butyl carbitol acetate; A glass paste A was prepared by kneading with this roll mill.

  In addition, ZnO-based glass frit material made of crystallized glass; 45 g, ethyl cellulose STD45 (manufactured by Dow Chemical Co.); 3 g, terpineol; 36.4 g, butyl carbitol acetate; A glass paste B was prepared by kneading.

  Using these glass pastes, a translucent substrate 1200 on which a high refractive material layer 120 was laminated was produced in the same manner as in Example 8 (FIG. 4B).

[Measurement method of warpage]
The amount of warpage was measured for each of the translucent substrates of Examples 1 to 12. For the measurement of the amount of warpage, a surface obtained by scanning a translucent substrate by 10 mm with a stylus type surface roughness measuring machine Surfcoder (manufactured by Kosaka Laboratory Ltd.) fixed at both ends of the substrate. The warpage amount was defined from the shape profile as shown in FIG. 9 (a) or (b).

  The results are shown in Table 1. It turns out that the amount of curvature improves the translucent board | substrate of this invention.

[Observation results of large area translucent substrate]
A translucent substrate in which the high refractive material layer described in Examples 1 to 12 is formed on an alkali-free glass substrate having a thickness of 0.7 mm and a G5 size (width 1100 × length 1250 mm), The surface condition was observed. The results are shown in Table 1. It can be seen that the translucent substrate of the present invention is good because no cracks or peeling is observed in the high refractive material layer.

[Examples of organic EL elements]
An organic EL element was produced using the translucent substrate of the present invention (element area was 0.04 cm ² ). On the translucent substrate of the present invention, ITO was formed as a transparent electrode by a 150 nm sputtering method. Thereafter, as a pretreatment, the transparent substrate having the ITO transparent electrode was cleaned with IPA and then treated with a UV ozone cleaner. PEDOT was formed to 20 nm as a hole injection layer, NPD was formed to 60 nm as a hole transport layer, and Alq3 was formed as a green light emitting layer by a vacuum deposition method of 40 nm. Further, 0.4 nm of LiF was deposited as an electron injection layer, and 100 nm of Al was deposited as a cathode to prepare an organic EL device. The organic EL device created as described above is transported into a glove box in a dry nitrogen atmosphere without being exposed to the surrounding air, and the organic EL device is sealed with a water-absorbing material containing barium oxide powder. The organic EL element was sealed by laminating using a plate and an ultraviolet curable resin sealant, and curing the sealant by ultraviolet irradiation.

The current-voltage-total luminous flux characteristics of the organic EL element obtained as described above were measured with a measurement system in which a KEITHLEY source meter 2400, an integrating sphere and an illuminometer were combined, and the current luminance efficiency (cd / A) was determined. Calculated. In addition, the current luminance efficiency of the organic EL element produced using an alkali free glass substrate was set to 1.0, and it was set as relative evaluation. The results are shown in Table 2 below.
In each of the organic EL elements using the translucent substrate of the present invention, it was confirmed that a current luminance efficiency of 1.5 times or more was obtained, and the light extraction efficiency was greatly improved.

From the above, by forming at least one glass material larger than the CTE _{glass of the} alkali-free glass substrate and forming the highly refractive material layer using at least one glass material smaller than the CTE _glass , Substrate distortion caused by the CTE difference between the refractive glass material and the alkali-free glass substrate can be eliminated, and a light-transmitting substrate capable of increasing the area as well as improving the light extraction efficiency can be provided.

100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200 Light emitting element 110 Non-alkali glass substrate 111 Concavity and convexity 120 High refractive index material layer 130 Transparent electrode 150 Organic light emitting layer (organic thin film layer )
180 Cathode 191 High refractive material layer 192 Non-alkali glass substrate

Claims (12)

An alkali-free glass substrate;
On the non-alkali glass substrate, a high refractive material layer containing at least one glass material larger than the linear expansion coefficient CTE _glass of the non-alkali glass substrate and containing at least one glass material smaller than the CTE _glass is provided. A light-transmitting substrate comprising: The translucent substrate according to claim 1, wherein an interface between the alkali-free glass substrate and the highly refractive material layer is uneven. The translucent substrate according to claim 1, wherein the high refractive material layer is made of a scattering material having a refractive index different from that of the glass material and the glass material. An alkali-free glass substrate;
It has a high refractive material layer composed of two or more layers including a layer made of at least one kind of glass material larger than the CTE _glass and a layer made of at least one kind of glass material smaller than the CTE _glass. Translucent substrate. The translucent substrate according to claim 4, wherein an interface between the alkali-free glass substrate and the highly refractive material layer is uneven. 6. The light transmitting device according to claim 4, wherein at least one of the two layers of the high refractive material layer is made of a scattering material having a refractive index different from that of the glass material and the glass material. Substrate. The translucent substrate according to any one of claims 1 to 6, wherein crystallized glass is contained in the high refractive material layer containing a glass material having a CTE smaller than the CTE _glass . 8. The translucent substrate according to claim 1, wherein the highly refractive material layer has a thickness of 40 μm or less. An organic electroluminescence element using the translucent substrate according to any one of claims 1 to 8. On the alkali-free glass substrate, a paste is prepared by mixing at least one glass frit material larger than the linear expansion coefficient CTE _glass of the alkali-free glass substrate and at least one glass frit material smaller than the CTE _glass ,
Applying the paste and drying to form a dry film,
A method for producing a light-transmitting substrate, comprising baking the dry film to form a highly refractive material layer. A paste A containing at least one glass frit material larger than the linear expansion coefficient CTE _glass of the alkali free glass substrate or a paste B containing at least one glass frit material smaller than the CTE _glass on the alkali free glass substrate. Applying one of the pastes, drying the paste to form a dry film, firing the dry film to form a first high refractive index layer, a first coating / drying / firing step;
On the high refractive material layer formed by the first application / drying / firing step, the paste that is not applied in the first application / drying / firing step among the paste A and the paste B is the first A method for producing a light-transmitting substrate, comprising: coating on a high refractive index layer; drying the paste to form a dry film; and firing the dry film to form a laminated high refractive material layer. . Paste A containing at least one glass frit material larger than the linear expansion coefficient CTE _glass of the alkali free glass substrate or paste B containing at least one glass frit material smaller than the CTE _glass on the alkali free glass substrate A first application / drying step of applying one of the pastes to obtain a first dry film;
On the first dry film formed by the first application / drying step, a paste that has not been applied in the first application / drying step is applied to the second dry film. A second coating / drying step to obtain a film;
A method for producing a light-transmitting substrate, comprising forming a laminated high refractive material layer by firing a laminated dry film formed after the second coating / drying step.