JP2015202971A - Phase-separated glass and composite substrate prepared using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To create a substrate material that contributes to improvements in the light extraction efficiency of an organic EL element without forming a light extraction layer comprising a sintered body on a glass substrate.SOLUTION: A phase-separated glass according to the present invention has a separate phase structure comprising at least a first phase and a second phase, wherein a difference between a maximum value of a total light transmittance at wavelengths of 400-700 nm and a minimum value of a total light transmittance at wavelengths of 400-700 nm is 40% or less.

Description

  The present invention relates to a phase-separated glass and a composite substrate using the same, and specifically to a phase-separated glass having a light scattering function and a composite substrate using the same.

  In recent years, energy consumed in living spaces such as homes has increased due to the widespread use, increase in size, and multifunctionality of home appliances. In particular, the energy consumption of lighting equipment is increasing. For this reason, highly efficient illumination is actively studied.

  Illumination light sources are classified into “directional light sources” that illuminate a limited range and “diffuse light sources” that illuminate a wide range. LED lighting corresponds to a “directional light source” and is being adopted as an alternative to an incandescent bulb. On the other hand, an alternative light source for a fluorescent lamp corresponding to a “diffusion light source” is desired, and organic EL (electroluminescence) illumination is a promising candidate.

  An organic EL element includes a substrate, a transparent conductive film as an anode, an organic EL layer including an organic compound that exhibits electroluminescence that emits light by current injection, or a plurality of light-emitting layers, and a cathode. It is. As the organic EL layer used in the organic EL element, a low molecular dye material, a conjugated polymer material or the like is used. When forming a light emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, an electron injection A laminated structure with layers and the like is formed. An organic EL layer having such a laminated structure is disposed between the anode and the cathode, and by applying an electric field to the anode and the cathode, holes injected from the transparent electrode that is the anode and those injected from the cathode The electrons recombine in the light emitting layer, and the emission center is excited by the recombination energy to emit light.

  Organic EL elements have been studied for use in mobile phones and displays, and some have already been put into practical use. In addition, the organic EL element has a luminous efficiency equivalent to that of a thin television such as a liquid crystal display or a plasma display.

  However, in order to apply the organic EL element to the light source for illumination, the luminance has not yet reached the practical level, and further improvement of the light emission efficiency is necessary.

JP 2012-25634 A

  In order to solve the above problems, it has been studied to use a glass substrate as a substrate and to form a light extraction layer between the glass substrate and a transparent conductive film. For example, in Patent Document 1, a light extraction layer in which a glass frit having a high refractive index is sintered is formed on the surface of a soda glass substrate, and a scattering substance is dispersed in the light extraction layer, whereby light extraction efficiency is obtained. It is described to increase.

However, in order to form the light extraction layer on the surface of the glass substrate, a printing process for applying a glass paste to the surface of the glass substrate is required, and this process causes an increase in production cost. In addition, when scattering particles are dispersed in the glass frit, the transmittance of the light extraction layer is lowered due to absorption of the scattering particles themselves. Furthermore, since the glass frit described in Patent Document 1 contains a large amount of rare metal oxide such as Nb ₂ O ₅ , the raw material cost is high.

  The present invention has been made in view of the above circumstances, and its technical problem contributes to the improvement of the light extraction efficiency of an organic EL element without forming a light extraction layer made of a sintered body on a glass substrate. The idea is to create a substrate material.

  As a result of intensive studies, the present inventors have found that the above technical problem can be solved by using a phase-separated glass having a light scattering function, and propose the present invention. That is, the phase separation glass of the present invention has a phase separation structure including at least a first phase and a second phase, and has a maximum total light transmittance at a wavelength of 400 to 700 nm and a total light transmission at a wavelength of 400 to 700 nm. The difference from the minimum value of the rate is 40% or less. Here, each phase of the “phase separation structure” can be confirmed in detail by, for example, observing the surface of the sample after being immersed in a 1M hydrochloric acid solution for 10 minutes with a scanning electron microscope. The phase-separated glass of the present invention may be used as a substrate material, but may be used as a material for bonding to a substrate as an alternative to the light extraction layer. The “total light transmittance” is a value measured in the thickness direction with a spectrophotometer (for example, UV-2500PC manufactured by Shimadzu Corporation). For example, glass whose both surfaces are mirror-polished is used as a measurement sample. it can.

  The phase separation glass of the present invention has a phase separation structure including at least a first phase and a second phase. In this way, when applied to an organic EL device, light incident on the phase separation glass from the organic EL layer is scattered at the interface between the first phase and the second phase, and the light extraction efficiency of the organic EL element Can be increased.

  On the other hand, when phase-separated glass is used, the wavelength dependency of transmittance tends to occur. In particular, when the size of the phase-separated particles is small, light having a short wavelength is scattered more strongly than light due to Rayleigh scattering, and when an organic EL element, particularly a white OLED, is produced, the color viewing angle dependency is large. Become. Therefore, if the difference between the maximum value of the total light transmittance at a wavelength of 400 to 700 nm and the minimum value of the total light transmittance at a wavelength of 400 to 700 nm is reduced to a predetermined value or less, such a problem can be easily solved.

  Secondly, the phase-separated glass of the present invention preferably has a thickness of 5 to 500 μm. If it does in this way, it will become easy to make a light-scattering function and high transmittance compatible.

  Third, the phase separation glass of the present invention preferably has a diffuse transmittance of 10% or more at a wavelength of 400 to 700 nm. In this way, when applied to an organic EL device, light incident on the phase separation glass from the organic EL layer is scattered at the interface between the first phase and the second phase, and the light extraction efficiency of the organic EL element Can be increased. Here, “diffuse transmittance” is a value measured in the thickness direction with a spectrophotometer (for example, UV-2500PC manufactured by Shimadzu Corporation). For example, glass whose both surfaces are mirror-polished is used as a measurement sample. it can.

Fourth, phase-separated glass of the present invention preferably has a refractive index n _d is 1.50 greater. One cause of the decrease in luminance is a mismatch in refractive index. For example, the refractive index _{n d} of the transparent conductive film is 1.9 to 2.0, the refractive index _{n d} of the organic EL layer is 1.8 to 1.9. In contrast, the refractive index _{n d} of the glass, usually about 1.50. Therefore, in the conventional organic EL device, light incident from the organic EL layer is reflected at the interface between the glass and the transparent conductive film due to a large difference in the refractive index between the glass and the transparent conductive film. There was a problem that decreased. Therefore, if regulating the refractive index n _d of the phase-separated glass, as described above, phase-separated glass and the smaller the refractive index difference between such transparent conductive films, transparent and light incident from the organic EL layer phase-separated glass conductive film It becomes difficult to reflect at the interface. Here, “refractive index n _d ” refers to the value of the d-line measured with a refractive index measuring device (for example, a refractive index measuring device KPR-2000 manufactured by Shimadzu Corporation).

Fifth, the phase-separated glass of the present invention preferably contains, as a glass composition, 30 to 75% of SiO ₂ , 1 to 50% of B ₂ O _{3, and} 1 to 60% of BaO. In this way, phase separation and devitrification resistance can be improved.

Sixth, it is preferable that the phase-separated glass of the present invention contains substantially no rare metal oxide in the glass composition. Here, the “rare metal oxide” referred to in the present invention is a rare earth oxide such as La ₂ O ₃ , Nd ₂ O ₃ , Gd ₂ O ₃ , CeO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O. ₅ points. Further, “substantially no rare metal oxide” means that the content of the rare metal oxide in the glass composition is 0.1% by mass or less.

  Seventh, the phase separation glass of the present invention is preferably used for an organic EL device. Here, the “organic EL device” includes not only organic EL illumination but also an organic EL display.

  Eighth, the composite substrate of the present invention is a composite substrate obtained by bonding a phase separation glass and a substrate, and the phase separation glass is preferably the above phase separation glass. If it does in this way, since phase separation glass functions as a light-scattering film, the light extraction efficiency of an organic EL element can be improved only by compounding with a substrate. Furthermore, if the phase separation glass and the substrate are bonded and the phase separation glass is disposed on the side in contact with air, the scratch resistance of the composite substrate can be improved. Here, the “phase-separated glass” is not limited to glass that has already undergone phase separation before bonding, but also includes glass that has undergone phase separation by a heat treatment step after bonding.

  Ninthly, in the composite substrate of the present invention, the substrate is preferably a glass substrate. A glass substrate is superior in permeability, weather resistance, and heat resistance compared to a resin substrate or a metal substrate.

Tenth, the composite substrate of the present invention, it preferably has a refractive index n _d of the substrate is 1.50 greater. In this way, since reflection at the interface between the organic EL layer and the substrate is suppressed, light in the substrate can be easily taken out into the air.

  Eleventh, in the composite substrate of the present invention, the phase separation glass and the substrate are preferably bonded by optical contact. In this way, since the adhesive tape and the curing agent are not required for joining, the transmittance of the composite substrate is improved, and the phase separation glass and the substrate can be easily joined. Note that the higher the surface accuracy (flatness) of the surface on the bonding side of the phase separation glass and the substrate, the higher the bonding strength of the optical contact.

  Twelfth, the composite substrate of the present invention is preferably used for an organic EL device.

Sample No. 1 is an image obtained by immersing 1 in a 1M hydrochloric acid solution for 10 minutes and then observing the sample surface with a scanning electron microscope. Sample No. 2 is an image obtained by immersing 2 in a 1 M hydrochloric acid solution for 10 minutes and then observing the surface of the sample with a scanning electron microscope. Sample No. This is data obtained by measuring the total light transmittance, diffuse transmittance, and haze value after processing 1 to a thickness of 0.1 mm. Sample No. This is data obtained by measuring the total light transmittance, diffuse transmittance, and haze value after processing 2 to a thickness of 0.1 mm.

Phase-separated glass of the present invention has a phase separation structure comprising at least a first phase and a second phase, the content of SiO ₂ in the first phase, containing SiO ₂ in the second phase it is preferably greater than the amount, also the content of B ₂ O ₃ in the second phase, it is also preferably larger than the content of B ₂ O ₃ in the first phase. If it does in this way, the refractive index of a 1st phase and a 2nd phase will become easy to differ, and the scattering function of phase-separated glass can be improved.

  In the phase separation glass of the present invention, the difference between the maximum value of the total light transmittance at a wavelength of 400 to 700 nm and the minimum value of the total light transmittance at a wavelength of 400 to 700 nm is preferably 40% or less, 30% or less, and 20%. Below, 10% or less, especially 5% or less. If the difference between the maximum value of the total light transmittance at a wavelength of 400 to 700 nm and the minimum value of the total light transmittance at a wavelength of 400 to 700 nm is too large, light of a short wavelength is scattered more strongly than light by a Rayleigh scattering. When an organic EL element, particularly a white OLED, is produced, the viewing angle dependency of color increases. In addition, if the size of the phase-separated particles is optimized to cause a scattering phenomenon due to Mie scattering, the wavelength dependency of the total light transmittance can be reduced. The size of the phase-separated particles can be adjusted by the glass composition, molding conditions, slow cooling conditions, heat treatment temperature, heat treatment time, and the like.

  It is preferable to control the size of the phase-separated particles in consideration of the refractive index of the first phase and the refractive index of the second phase, and it is also possible to control the size of the phase-separated particles within a range that causes Mie scattering. preferable. The size of the phase-separated particles is not particularly limited, but examples of suitable sizes include 200 nm or more, 400 nm or more, 600 nm or more, 800 nm or more, and particularly 1 μm or more.

  The thickness of the phase separation glass of the present invention is preferably 5 to 500 μm. If the thickness is too large, if the light scattering function is excessive, the total light transmittance becomes low, and it becomes difficult to extract the light in the phase separation glass into the air. Therefore, the thickness is preferably 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, particularly 50 μm or less. On the other hand, if the thickness is too small, the light scattering function tends to be lowered, and it becomes difficult to take out the light in the phase separation glass into the air. Therefore, the thickness is preferably 5 μm or more, 10 μm or more, 20 μm or more, particularly 30 μm or more.

  In the phase-separated glass of the present invention, the total light transmittance at a wavelength of 400 to 700 nm is preferably 20% or more, 30% or more, 40% or more, and particularly 50% or more. If the total light transmittance is too low, it becomes difficult to extract the light in the phase separation glass into the air.

  In the phase separation glass of the present invention, the diffuse transmittance at a wavelength of 400 to 700 nm is preferably 10% or more, 20% or more, 30% or more, 40% or more, particularly 50% or more. If the diffuse transmittance is too low, it becomes difficult to extract the light in the phase separation glass into the air.

  In the phase-separated glass of the present invention, the haze value at a wavelength of 400 to 700 nm is preferably 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more. In particular, it is 90% or more. If the haze value is too low, the light scattering function becomes insufficient, and it becomes difficult to extract the light in the phase separation glass into the air. Here, the “haze value” is a value calculated by [(diffuse transmittance) × 100] / (total light transmittance).

In the phase separation glass of the present invention, the refractive index _nd is preferably more than 1.50, 1.52 or more, 1.53 or more, 1.54 or more, particularly 1.55 or more. When the refractive index _nd is 1.50 or less, it becomes difficult to efficiently extract light due to reflection at the interface between the phase separation glass and the transparent conductive film. On the other hand, when the refractive index _nd is too high, the reflectance at the interface between the phase separation glass and the air becomes high, and it becomes difficult to extract the light in the phase separation glass into the air. Therefore, the refractive index _{n d} is preferably 2.30 or less, 2.20 or less, 2.10 or less, 2.00 or less, 1.90 or less, particularly 1.80 or less.

The phase-separated glass of the present invention preferably contains, as a glass composition, 30 to 70% of SiO ₂ , 1 to 50% of B ₂ O ₃ and 10 to 60% of BaO. Hereinafter, the reason why each component is limited as described above will be described. In addition, in description of the containing range of each component,% display means the mass%.

The content of SiO ₂ is preferably 30 to 70%. When the content of SiO ₂ increases, the meltability, moldability, and refractive index tend to decrease. Therefore, a suitable upper limit range of SiO ₂ is 70% or less, 65% or less, particularly 60% or less. On the other hand, when the content of SiO ₂ decreases, it becomes difficult to form a glass network structure, and vitrification becomes difficult. Further, the viscosity of the glass is excessively lowered, and it becomes difficult to ensure a high liquid phase viscosity. Therefore, a suitable lower limit range of SiO ₂ is 30% or more, 35% or more, particularly 40% or more.

The content of B ₂ O ₃ is preferably 1 to 50%. B ₂ O ₃ is a component that enhances phase separation, but if the content of B ₂ O ₃ is too large, the component balance of the glass composition is impaired, and devitrification resistance is likely to decrease. The acid resistance tends to decrease. Therefore, a preferable upper limit range of B ₂ O ₃ is 50% or less, particularly 40% or less, and a preferable lower limit range is 1% or more, 4% or more, 7% or more, 10% or more, 15% or more, particularly 20%. % Or more.

  The BaO content is preferably 1 to 60%. BaO is a component that increases the refractive index of alkaline earth metal oxides without extremely reducing the viscosity of the glass. On the other hand, when the content of BaO increases, the component balance of the glass composition is impaired, and the devitrification resistance is likely to decrease. Therefore, the preferable upper limit range of BaO is 60% or less, 50% or less, particularly 40% or less, and the preferable lower limit range is 1% or more, 10% or more, particularly 20% or more.

  In addition to the above components, for example, the following components can be introduced.

The content of Al ₂ O ₃ is preferably 0 to 35%. Al ₂ O ₃ is a component that enhances devitrification resistance. However, if the content of Al ₂ O ₃ is too large, the phase separation is liable to decrease, and the component balance of the glass composition is impaired. Conversely, devitrification resistance tends to decrease. Moreover, acid resistance tends to decrease. Therefore, the preferred upper limit range of Al ₂ O ₃ is 35% or less, 30% or less, 25% or less, less than 23%, particularly 20% or less, and the preferred lower limit range is 0.1% or more, 3% or more, 5% or more, 8% or more, particularly 10% or more.

The content of Li ₂ O is preferably 0 to 30%. Li ₂ O is a component that enhances phase separation. However, if the content of Li ₂ O is too large, the liquid phase viscosity tends to decrease and the strain point tends to decrease. Furthermore, the alkali component is easily eluted in the acid etching step. Therefore, the preferable upper limit range of Li ₂ O is 30% or less, 20% or less, 10% or less, 5% or less, 1% or less, particularly 0.5% or less.

The content of Na ₂ O is preferably 0 to 30%. Na ₂ O is a component that enhances the phase separation. However, when the content of Na ₂ O is too large, the liquid phase viscosity tends to decrease and the strain point tends to decrease. Furthermore, the alkali component is easily eluted in the acid etching step. Therefore, the preferable upper limit range of Na ₂ O is 30% or less, 20% or less, 10% or less, 5% or less, 1% or less, particularly 0.5% or less.

The content of K ₂ O is preferably 0 to 30%. K ₂ O is a component that enhances phase separation. However, if the content of K ₂ O is too large, the liquid phase viscosity tends to decrease and the strain point tends to decrease. Furthermore, the alkali component is easily eluted in the acid etching step. Therefore, a preferable upper limit range of K ₂ O is 30% or less, 20% or less, 10% or less, 5% or less, 1% or less, particularly 0.5% or less.

  The content of MgO is preferably 0 to 30%. MgO is a component that raises the refractive index, Young's modulus, and strain point and lowers the high-temperature viscosity. However, when MgO is contained in a large amount, the liquidus temperature rises and devitrification resistance decreases. Or the density may become too high. Therefore, a preferable upper limit range of MgO is 30% or less, 20% or less, particularly 10% or less, and a preferable lower limit range is 0.1% or more, 1% or more, 3% or more, particularly 5% or more.

  The content of CaO is preferably 0 to 30%. CaO is a component that lowers the high-temperature viscosity. However, when the content of CaO increases, the density tends to increase, and the balance of components of the glass composition is impaired, and devitrification resistance tends to decrease. Therefore, a preferable upper limit range of CaO is 30% or less, 20% or less, particularly 10% or less, 5% or less, particularly 3% or less, and a preferable lower limit range is 0.1% or more, 0.5% or more, In particular, it is 1% or more.

  The content of SrO is preferably 0 to 30%. If the SrO content is increased, the refractive index and the density are likely to be increased, and the balance of components of the glass composition is impaired, so that the devitrification resistance is likely to be lowered. Therefore, the preferable upper limit range of SrO is 30% or less, 20% or less, particularly 10% or less, and the preferable lower limit range is 1% or more, 3% or more, particularly 5% or more.

  The content of ZnO is preferably 0 to 30%. When the ZnO content is increased, the refractive index and density are likely to be increased, the balance of the components of the glass composition is impaired, and devitrification resistance is likely to be reduced. Therefore, the preferable upper limit range of ZnO is 30% or less, 20% or less, particularly 10% or less, and the preferable lower limit range is 1% or more, 3% or more, particularly 5% or more.

TiO ₂ is a component that increases the refractive index. The content of TiO ₂ is preferably 0 to 20%. However, when the content of TiO ₂ is increased, the component balance of the glass composition is impaired, and the devitrification resistance is easily lowered. In addition, the total light transmittance may be reduced. Therefore, the preferable upper limit range of TiO ₂ is 20% or less, particularly 10% or less, and the preferable lower limit range is 0.001% or more, 0.01% or more, 0.1% or more, 1% or more, 2% Above, especially 3% or more.

ZrO ₂ is a component that increases the refractive index. The content of ZrO ₂ is preferably 0 to 20%. However, when the content of ZrO ₂ increases, the component balance of the glass composition is impaired, and the devitrification resistance is likely to decrease. Therefore, the preferable upper limit range of ZrO ₂ is 20% or less, 10% or less, particularly 5% or less, and the preferable lower limit range is 0.001% or more, 0.01% or more, 0.1% or more, 1%. Above, 2% or more, especially 3% or more.

La ₂ O ₃ is a component that increases the refractive index. The content of La ₂ O ₃ is preferably 0 to 10%. When the content of La ₂ O ₃ increases, the density tends to increase, and the devitrification resistance and acid resistance easily decrease. Furthermore, the raw material cost rises and the production cost of the phase separation glass is likely to rise. Therefore, a suitable upper limit range of La ₂ O ₃ is 10% or less, 5% or less, 3% or less, 2.5% or less, 1% or less, particularly 0.1% or less.

Nb ₂ O ₅ is a component that increases the refractive index. The content of Nb ₂ O ₅ is preferably 0 to 10%. When the content of Nb ₂ O ₅ increases, the density tends to increase and the devitrification resistance tends to decrease. Furthermore, the raw material cost rises and the production cost of the phase separation glass is likely to rise. Therefore, a preferable upper limit range of Nb ₂ O ₅ is 10% or less, 5% or less, 3% or less, 2.5% or less, 1% or less, particularly 0.1% or less.

Gd ₂ O ₃ is a component that increases the refractive index. The content of Gd ₂ O ₃ is preferably 0 to 10%. When the content of Gd ₂ O ₃ is increased, the density becomes too high, the component balance of the glass composition is lacking, the devitrification resistance is lowered, the high temperature viscosity is lowered too much, and a high liquid phase viscosity is secured. It becomes difficult to do. Therefore, a suitable upper limit range of Gd ₂ O ₃ is 10% or less, 5% or less, 3% or less, 2.5% or less, 1% or less, particularly 0.1% or less.

The content of La ₂ O ₃ + Nb ₂ O ₅ is preferably 0 to 10%. When the content of La ₂ O ₃ + Nb ₂ O ₅ is increased, the density and the thermal expansion coefficient are likely to be increased, the devitrification resistance is likely to be lowered, and further, it is difficult to ensure a high liquid phase viscosity. Furthermore, the raw material cost rises and the production cost of the phase separation glass is likely to rise. Therefore, a suitable upper limit range of La ₂ O ₃ + Nb ₂ O ₅ is 10% or less, 8% or less, 5% or less, 3% or less, 1% or less, 0.5% or less, particularly 0.1% or less. . Here, “La ₂ O ₃ + Nb ₂ O ₅ ” refers to the total amount of La ₂ O ₃ and Nb ₂ O ₅ .

  The total content of rare metal oxides is preferably 0 to 10%. When the content of the rare metal oxide is increased, the density and the thermal expansion coefficient are likely to be increased, and the devitrification resistance and the acid resistance are liable to be lowered, so that it is difficult to ensure a high liquid phase viscosity. Furthermore, the raw material cost rises, and the manufacturing cost of the glass plate is likely to rise. Therefore, the preferable upper limit range of the rare metal oxide is 10% or less, 5% or less, 3% or less, particularly 1% or less, and it is desirable that the rare metal oxide is not substantially contained.

As a refining agent, one or two or more selected from the group of As ₂ O ₃ , Sb ₂ O ₃ , SnO ₂ , Fe ₂ O ₃ , F, Cl, SO ₃ , and CeO ₂ are converted into the following oxides. ~ 3% can be introduced. In particular, SnO ₂ , Fe ₂ O ₃ and CeO ₂ are preferable as the fining agent. On the other hand, it is preferable to refrain from using As ₂ O ₃ and Sb ₂ O ₃ as much as possible from an environmental viewpoint, and the content of each is preferably less than 0.3%, particularly preferably less than 0.1%. Here, “the following oxide conversion” means that an oxide having a valence different from the indicated oxide is handled after being converted to the indicated oxide.

The content of SnO ₂ is preferably 0 to 1%, 0.001 to 1%, particularly 0.01 to 0.5%.

Fe ₂ O _{3 has} a preferred upper limit range of 0.05% or less, 0.04% or less, 0.03% or less, particularly 0.02% or less, and a preferred lower limit range of 0.001% or more.

The content of CeO ₂ is preferably 0 to 6%. When the content of CeO ₂ is increased, the devitrification resistance is likely to be lowered. Therefore, the preferable upper limit range of CeO ₂ is 6% or less, 5% or less, 3% or less, 2% or less, 1% or less, particularly 0.1% or less. On the other hand, when the CeO ₂ content is reduced, the clarity is likely to be lowered. Therefore, when CeO ₂ is introduced, a preferable lower limit range of CeO ₂ is 0.001% or more, particularly 0.01% or more.

  PbO is a component that lowers the high-temperature viscosity, but it is preferable to refrain from using it as much as possible from an environmental point of view. The content of PbO is preferably 0.5% or less, and is desirably substantially free. Here, “substantially does not contain PbO” refers to a case where the content of PbO in the glass composition is less than 0.1%.

  In addition to the above components, other components may be introduced in a total amount of preferably 10% (desirably 5%).

  The phase-separated glass of the present invention preferably has the following characteristics.

The density is preferably 2.4 g / cm ³ or more, 2.7 g / cm ³ or more, particularly 3.0 g / cm ³ or more. If the density is too low, easily refractive index n _d decreases, when applied to an organic EL device, the more the light is confined in the organic EL layer / transparent conductive lining, light extraction efficiency is likely to decrease as a result . On the other hand, if the density is too high, it is difficult to reduce the weight of the device. Therefore, the density is preferably 5.0 g / cm ³ or less, 4.5 g / cm ³ or less, particularly 4.0 g / cm ³ or less.

The temperature at 10 ^2.5 dPa · s is preferably 1600 ° C. or lower, 1560 ° C. or lower, 1500 ° C. or lower, 1450 ° C. or lower, 1400 ° C. or lower, particularly 1350 ° C. or lower. If it does in this way, since meltability will improve, productivity of phase separation glass will improve.

  As for surface roughness Ra of at least one surface (especially unpolished surface), 0.01-1 micrometer is preferable. If the surface roughness Ra is too large, it becomes difficult to produce a composite substrate by optical contact. In addition, when a transparent conductive film or the like is formed on the surface, the quality of the transparent conductive film is lowered and uniform. It becomes difficult to obtain luminescence. Therefore, the preferable upper limit range of the surface roughness Ra of at least one surface is 1 μm or less, 0.8 μm or less, 0.5 μm or less, 0.3 μm or less, 0.1 μm or less, 0.07 μm or less, 0.05 μm or less, 0.03 μm or less, particularly 10 nm or less.

  The phase separation glass of the present invention is preferably formed by a downdraw method, particularly an overflow downdraw method. In this way, unpolished glass with good surface quality can be produced. The reason is that, in the case of the overflow down draw method, the surface to be the surface is not in contact with the bowl-shaped refractory and is molded in a free surface state. In addition to the overflow downdraw method, a slot downdraw method can be employed. If it does in this way, it will become easy to produce glass with a small board thickness.

  In addition to the above molding method, for example, a redraw method, a float method, a roll-out method, or the like can be adopted.

The phase-separated glass of the present invention may have at least one surface as a roughened surface. If the roughened surface is arranged on the side in contact with air such as organic EL lighting, in addition to the scattering effect of the phase separation glass, the light emitted from the organic EL layer is reflected by the non-reflective structure of the roughened surface. As a result, the light extraction efficiency can be increased. The surface roughness Ra of the roughened surface is preferably 10 mm or more, 20 mm or more, 30 mm or more, particularly 50 mm or more. The roughened surface can be formed by HF etching, sandblasting, or the like. Moreover, you may form an uneven | corrugated shape in the surface of phase-separated glass by heat processing, such as repress. In this way, an accurate non-reflective structure can be formed on the glass surface. Uneven shape, taking into account the refractive index n _d, may be adjusted the spacing and depth.

Further, the roughened surface can be formed by an atmospheric pressure plasma process. If it does in this way, while maintaining the surface state of one surface of phase-separated glass, a roughening process can be uniformly performed with respect to the other surface. Moreover, it is preferable to use a gas containing F (for example, SF ₆ , CF ₄ ) as a source of the atmospheric pressure plasma process. In this way, since plasma containing HF gas is generated, the roughened surface can be formed efficiently.

  Furthermore, a roughened surface can be formed on at least one surface during the molding of the phase separation glass. This eliminates the need for a separate roughening process and improves the efficiency of the roughening process.

  In addition, you may affix the resin film which has a predetermined uneven | corrugated shape on the surface of phase separation glass, without forming a roughening surface in phase separation glass.

  The phase-separated glass of the present invention is preferably phase-separated in a molding step and / or a slow cooling step from the viewpoint of production efficiency, but may be phase-separated in a melting step other than these steps, for example. Further, from the viewpoint of controlling the phase separation structure, the phases may be separated by a separate heat treatment step. The phase separation phenomenon can be adjusted by the glass composition, molding conditions, slow cooling conditions, heat treatment temperature, heat treatment time, and the like.

  The composite substrate of the present invention is a composite substrate obtained by bonding a phase separation glass and a substrate, and the phase separation glass is the phase separation glass described above. If it does in this way, since phase separation glass functions as a light-scattering film, the light extraction efficiency of an organic EL element can be improved only by compounding with a substrate. Furthermore, if the phase separation glass and the substrate are bonded and the phase separation glass is disposed on the side in contact with air, the scratch resistance of the composite substrate can be improved.

  Various materials can be used as the substrate. For example, a resin substrate, a metal substrate, or a glass substrate can be used. Among these, a glass substrate is preferable from the viewpoints of permeability, weather resistance, and heat resistance. Various materials can be used as the glass substrate. For example, a soda lime glass substrate, an aluminosilicate glass substrate, and an alkali-free glass substrate can be used.

  The thickness of the glass substrate is preferably 0.3 to 3.0 mm, 0.4 to 2.0 mm, particularly more than 0.5 to 1.8 mm from the viewpoint of maintaining strength.

Refractive index _{n d} of the glass substrate is preferably 1.50 greater, 1.51 or more, 1.52 or more, 1.53 or more, 1.54 or more, 1.55 or more, 1.56 or more, 1.60 or more In particular, it is 1.63 or more. If the refractive index of the glass substrate is too low, it becomes difficult to efficiently extract light by reflection at the interface of the glass substrate and the transparent conductive film. On the other hand, if the refractive index _nd is too high, the reflectance at the interface between the glass substrate and the phase separation glass becomes high, and it becomes difficult to extract the light in the glass substrate into the air through the phase separation glass. Therefore, the refractive index _{n d} is preferably 2.30 or less, 2.20 or less, 2.10 or less, 2.00 or less, 1.90 or less, 1.80 or less, particularly 1.75 or less.

  As for surface roughness Ra of at least one surface (especially unpolished surface) of a glass substrate, 0.01-1 micrometer is preferable. If the surface roughness Ra of the surface is too large, it becomes easy to produce a composite substrate by optical contact. In addition, when a transparent conductive film or the like is formed on the surface, the quality of the transparent conductive film is lowered and uniform. It becomes difficult to obtain luminescence. Therefore, the preferable upper limit range of the surface roughness Ra of at least one surface is 1 μm or less, 0.8 μm or less, 0.5 μm or less, 0.3 μm or less, 0.1 μm or less, 0.07 μm or less, 0.05 μm or less, 0.03 μm or less, particularly 10 nm or less.

  Various methods can be used as a method for bonding the phase separation glass and the substrate. For example, a method of joining with an adhesive tape, an adhesive sheet, an adhesive, a curing agent, or the like, or a method of joining with an optical contact can be used. Among these, from the viewpoint of increasing the transmittance of the composite substrate, a method of joining with an optical contact is preferable.

  Hereinafter, based on an Example, this invention is demonstrated in detail. The following examples are merely illustrative. The present invention is not limited to the following examples.

  Table 1 shows Sample No. 1 and 2 are shown.

  First, after preparing a glass raw material so that it might become a glass composition of Table 1, the obtained glass batch was supplied to the glass melting furnace, and it melted at 1500 degreeC for 8 hours. Next, the obtained molten glass was poured onto a carbon plate, formed into a plate shape, and then slowly cooled from the strain point to room temperature over 10 hours. Finally, the obtained glass (Sample Nos. 1 and 2) was processed as necessary to evaluate various properties.

  The density is a value measured by a well-known Archimedes method.

The temperatures at high temperature viscosities of 10 ^4.0 dPa · s, 10 ^3.0 dPa · s, 10 ^2.5 dPa · s, and 10 ^2.0 dPa · s are values measured by the platinum ball pulling method. In addition, it is excellent in a meltability, so that high temperature viscosity is low.

In sample No. 1 according to [Example 1]. After immersing 1 and 2 in a 1M hydrochloric acid solution for 10 minutes, the sample surface was observed with a scanning electron microscope (S-4300SE, manufactured by Hitachi High-Technologies Corporation). 1 and 2 show sample Nos. The image of the scanning electron microscope of the surface of 1 and 2 is each shown. As can be seen from FIGS. 1 and 2 had a phase separation structure. If the glass is phase-separated, the phase rich in B ₂ O ₃ is eluted by the hydrochloric acid solution, and the phase rich in SiO ₂ remains without being eluted in the hydrochloric acid solution.

  Sample No. About 1 and 2, after processing so that thickness might be set to 0.1 mm, both surfaces were mirror-polished. Next, with respect to the wavelength range in the figure, the total light transmittance and diffuse transmittance in the thickness direction were measured with a spectrophotometer (Spectrophotometer UV-2500PC manufactured by Shimadzu Corporation). From both results, the haze value was determined. The results are shown in FIGS. 3 and 4, the total light transmittance and diffuse transmittance data overlap.

  As can be seen from FIGS. 1 and 2, the difference between the maximum value of the total light transmittance at a wavelength of 400 to 700 nm and the minimum value of the total light transmittance at a wavelength of 400 to 700 nm is within 2%, and the total light transmittance at a wavelength of 400 to 700 nm. Was 50% or more, and the diffuse transmittance at a wavelength of 400 to 700 nm was 50% or more.

Sample No. After the molten glass having the glass composition of 1 was poured onto the carbon, a slow cooling treatment was performed to obtain a phase-separated glass in which the surface on the side not in contact with the carbon was a free surface. Next, the surface on the side in contact with the carbon was polished to obtain a phase separation glass having a thickness of 200 μm. Subsequently, the obtained phase separation glass was washed with pure water to remove impurities attached to the surface. Further, a glass substrate with a high refractive index (manufactured by Nippon Electric Glass Co., Ltd. HX-1: refractive index _n d 1.63, thickness 0.7 mm) was prepared. This glass substrate is formed by the overflow downdraw method, and the average surface roughness Ra of the surface is 0.2 nm. Finally, the free surface of the phase separation glass and one surface of the glass substrate were joined by optical contact to obtain a composite substrate.

Sample No. After the molten glass having the glass composition of 2 was poured out onto the carbon, a slow cooling treatment was performed to obtain a phase-separated glass in which the surface on the side not in contact with the carbon was a free surface. Next, the surface on the side in contact with the carbon was polished to obtain a phase separation glass with a thickness of 50 μm. Subsequently, the obtained phase separation glass was washed with pure water to remove impurities attached to the surface. Further, a glass substrate with a high refractive index (manufactured by Nippon Electric Glass Co., Ltd. HX-1: refractive index _n d 1.63, thickness 0.7 mm) was prepared. This glass substrate is formed by the overflow downdraw method, and the average surface roughness Ra of the surface is 0.2 nm. Finally, the free surface of the phase separation glass and one surface of the glass substrate were joined by optical contact to obtain a composite substrate.

Claims (12)

  It has a phase separation structure including at least a first phase and a second phase, and the difference between the maximum value of the total light transmittance at a wavelength of 400 to 700 nm and the minimum value of the total light transmittance at a wavelength of 400 to 700 nm is 40% A phase-separated glass characterized by:   Thickness is 5-500 micrometers, The phase separation glass of Claim 1 characterized by the above-mentioned.   The phase separation glass according to claim 1, wherein the diffuse transmittance at a wavelength of 400 to 700 nm is 10% or more. Phase-separated glass according to any one of claims 1 to 3, the refractive index n _d is equal to or is 1.50 greater. As a glass composition, in _{mass%, SiO 2 30~75%, B} 2 O 3 1~50%, phase separation according to any one of claims 1 to 4, characterized in that it contains 1 to 60% BaO Glass.   The phase-separated glass according to any one of claims 1 to 5, wherein the glass composition contains substantially no rare metal oxide.   It uses for an organic EL device, The phase-separated glass in any one of Claims 1-6 characterized by the above-mentioned. A composite substrate obtained by bonding a phase separation glass and a substrate,
A composite substrate, wherein the phase separation glass is the phase separation glass according to any one of claims 1 to 6.   The composite substrate according to claim 8, wherein the substrate is a glass substrate. Composite substrate according to claim 8 or 9 refractive index n _d of the substrate is characterized by a 1.50 greater.   The composite substrate according to claim 8, wherein the phase separation glass and the substrate are bonded by optical contact.   The composite substrate according to claim 8, wherein the composite substrate is used for an organic EL device.