TWI538891B - High refractivity glass - Google Patents

Description

High refractive index glass

The present invention relates to a high refractive index glass, for example, to a high refractive index glass suitable for use in an organic EL element, particularly organic EL illumination.

In recent years, displays and illumination using organic EL light-emitting elements have received increasing attention. The organic EL device has a structure in which an organic light-emitting device is sandwiched by a substrate (glass plate) on which a transparent conductive film such as ITO or FTO is formed (for example, see JP-A-2007-149460). In this configuration, when a current flows into the organic light-emitting element, the holes in the organic light-emitting element merge with the electrons to emit light. The emitted light enters the glass plate through the transparent conductive film, and is output to the outside while being repeatedly reflected in the glass plate.

However, the refractive index nd of the organic light-emitting element is 1.8 to 1.9, and the refractive index nd of the transparent electrode film is 1.9 to 2.0. On the other hand, the refractive index nd of a glass substrate is normally about 1.5. Therefore, the organic EL device of the prior art has a problem that the reflectance is high and the light emitted from the organic light-emitting element cannot be efficiently output due to the difference in refractive index between the glass substrate and the ITO interface.

If a high refractive index glass is used as the glass plate, the refractive index difference at the interface between the glass plate and the transparent electrode film can be reduced.

As the high refractive index glass, an optical glass used for an optical lens or the like is known. In an optical lens or the like, an optical glass which is heat-press molded into a predetermined shape by applying heat treatment to a droplet glass formed into a spherical shape by a droplet forming method or the like is used. Although the optical glass has a high refractive index nd but a low liquid phase viscosity, If it is not formed by a droplet forming method or the like which has a high cooling rate, the glass will be devitrified during molding. Therefore, in order to solve the above problems, it is necessary to improve the devitrification resistance of the high refractive index glass.

However, in order to reduce the thickness and size of an organic EL display or the like, it is required to develop a glass plate having a small thickness and a large area. In order to obtain such a glass plate, it is necessary to form by a float method or a down draw method (overflow down draw method, slot down draw method). However, since the conventional high refractive index glass has a low liquid phase viscosity, it cannot be formed by a floating method or a downdraw method, and it is difficult to achieve thinning and enlargement. In addition, even in the case of organic EL illumination, there is a demand for thinning and enlargement.

On the other hand, when an oxide, particularly LaO, Nb ₂ O ₅ or Gd ₂ O ₃ is added to the glass composition, the decrease in the viscosity of the liquid phase can be suppressed to some extent, and the refractive index nd of the glass plate can be increased. However, such rare metal oxides have a problem of high raw material cost. Further, when a rare metal oxide is added in a large amount to the glass composition, the devitrification resistance is lowered, and it is difficult to form a glass plate. Further, in the case where a rare metal oxide is added in a large amount, oxidation resistance is also lowered.

Therefore, a technical object of the present invention is to provide a refraction with an organic light-emitting element or a transparent electrode film although the content of a rare metal oxide (particularly La ₂ O ₃ , Nb ₂ O ₅ , Gd ₂ O ₃ ) is small. High refractive index glass with a matching rate of nd and good resistance to devitrification.

<First invention>

As a result of intensive studies, the inventors of the present invention have found that the above-mentioned technical problems can be solved by setting the range and refractive index of each component within a predetermined range, and are proposed as the first invention. In other words, the high refractive index glass according to the first aspect of the invention is characterized in that it contains 0 to 10% of B ₂ O ₃ , 0.001% to 35% of SrO, and 0.001% to 30% of ZrO as a glass composition. ₂ + TiO ₂ , 0 to 10% of La ₂ O ₃ + Nb ₂ O ₅ , mass ratio BaO/SrO is 0 to 40, mass ratio SiO ₂ /SrO is 0.1 to 40, and refractive index nd is 1.55 to 2.3. Here, "ZrO ₂ + TiO ₂ " means the total amount of ZrO ₂ and TiO ₂ . "La ₂ O ₃ + Nb ₂ O ₅ " means the total amount of La ₂ O ₃ and Nb ₂ O ₅ . The "refractive index nd" can be measured using a commercially available refractive index measuring instrument, for example, a rectangular parallelepiped sample of 25 mm × 25 mm × about 3 mm, and then (annealing point Ta + 30 ° C) to (strain point Ps - 50 ° C) The temperature range was annealed at a cooling rate of 0.1 ° C/min, and then the refractive index-matched immersion liquid was infiltrated into the glass, and in this state, it was measured by using a refractive index meter KPR-2000 manufactured by Shimadzu Corporation. The "annealing point Ta" means a value measured in accordance with the method described in ASTM C338-93. The "strain point Ps" is a value measured in accordance with the method described in ASTM C336-71.

Secondly, the high refractive index glass of the first invention preferably has a liquid phase viscosity of 10 ^3.0 dPa or more. s. Here, the "liquid phase viscosity" refers to a value obtained by measuring the viscosity of the glass at a liquidus temperature by a platinum ball pulling method. "Liquid phase temperature" means that the glass powder which has passed through a 30 mesh (500 μm) standard sieve and left on a 50 mesh (300 μm) sieve is placed in a platinum boat and kept in a temperature gradient furnace for 24 hours, after which the crystal precipitation is measured. The value obtained by the temperature.

Third, the high refractive index glass of the first invention is preferably plate-shaped. this The "plate shape" is not limited to a shape including a film having a small thickness, for example, a film having a film shape along a column, and a glass having a concavo-convex shape formed on one surface.

Fourth, the high refractive index glass of the first invention is preferably formed by a float method.

5. The high refractive index glass of the first invention is preferably 10 ⁴ dPa. The temperature under s is 1250 ° C or less. Here, "temperature at 10 ^4.0 dPa.s" means a value measured by a platinum ball pulling method.

Sixth, the high refractive index glass of the first invention preferably has a strain point of 650 ° C or higher.

Seventh, the high refractive index glass of the first invention is preferably used for a lighting element.

Eighth, the high refractive index glass of the first invention is preferably used for organic EL illumination.

Ninth, the high refractive index glass of the first invention is preferably used for an organic EL display.

According to a tenth aspect, the high refractive index glass of the first aspect of the invention is characterized in that it contains 0 to 8% of B ₂ O ₃ , 0.001% to 35% of SrO, and 0 to 12% of ZnO as a glass composition. 0.001%~30% ZrO ₂ +TiO ₂ , 0~5% La ₂ O ₃ +Nb ₂ O ₅ , 0~10% Li ₂ O+Na ₂ O+K ₂ O, and the mass ratio BaO/ The SrO is 0-20, the mass ratio SiO ₂ /SrO is 0.1-20, the mass ratio (MgO+CaO)/SrO is 0-20, the refractive index nd is 1.58 or more, and the liquid viscosity is 10 ^3.5 dPa. Above s, the strain point is 670 ° C or more. Here, "Li ₂ O+Na ₂ O+K ₂ O" means the total amount of Li ₂ O, Na ₂ O, and K ₂ O. "MgO+CaO" means the total amount of MgO and CaO.

The high-refractive-index glass according to the first aspect of the invention is characterized in that, as a glass composition, 10% to 50% of SiO ₂ , 0 to 8% of B ₂ O ₃ , and 0 to 10% are calculated by mass%. CaO, 0.001% to 35% SrO, 0 to 30% BaO, 0 to 4% ZnO, 0.001% to 30% ZrO ₂ + TiO ₂ , 0 to 5% La ₂ O ₃ + Nb ₂ O ₅ , 0~2% Li ₂ O+Na ₂ O+K ₂ O, and the mass ratio BaO/SrO is 0~20, the mass ratio SiO ₂ /SrO is 1~15, mass ratio (MgO+CaO)/SrO 0~20, the refractive index nd is 1.6 or more, and the liquid viscosity is 10 ^4.0 dPa. Above s, the strain point is 670 ° C or more.

According to a twelfth aspect, the glass plate for an illumination device according to the first aspect of the invention is characterized in that the glass composition contains 0.1% to 60% of SiO ₂ and 0 to 10% of B ₂ O ₃ and 0.001% by mass%. 35% SrO, 0-40% BaO, 0.001%-30% ZrO ₂ +TiO ₂ , 0-10% La ₂ O ₃ +Nb ₂ O ₅ , and the refractive index nd is 1.55-2.3.

The glass plate for organic EL illumination according to the first aspect of the invention, characterized in that the glass composition contains 0.1% to 60% of SiO ₂ , 0 to 10% of B ₂ O ₃ , and 0.001% by mass%. ~35% of SrO, 0-40% of BaO, 0.001% to 30% of ZrO ₂ +TiO ₂ , 0 to 10% of La ₂ O ₃ +Nb ₂ O ₅ , and a refractive index nd of 1.55 to 2.3.

A glass plate for an organic EL display according to the first aspect of the invention, which comprises, as a glass composition, 0.1% to 60% of SiO ₂ , 0 to 10% of B ₂ O ₃ , and 0.001% by mass%. ~35% of SrO, 0-40% of BaO, 0.001% to 30% of ZrO ₂ +TiO ₂ , 0 to 10% of La ₂ O ₃ +Nb ₂ O ₅ , and a refractive index nd of 1.55 to 2.3.

According to a fifteenth aspect, the high refractive index glass of the first aspect of the invention is characterized in that, as a glass composition, 35% to 60% of SiO ₂ and 0 to 1.5% of Li ₂ O+Na ₂ O+K are contained by mass%. ₂ O, 0.1% to 35% SrO, 0 to 35% BaO, 0.001% to 25% TiO ₂ , 0 to 9% La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ , and refractive index Nd is 1.55~2.3. Here, "La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ " means the total amount of La ₂ O ₃ , Nb ₂ O ₅ and Gd ₂ O ₃ .

According to a sixteenth aspect, the high refractive index glass of the first aspect of the invention is characterized in that, as a glass composition, 35% to 60% of SiO ₂ and 0 to 1.5% of Li ₂ O+Na ₂ O+K are contained by mass%. ₂ O, 0.1% to 20% SrO, 17% to 35% BaO, 0.01% to 20% TiO ₂ , 0 to 9% La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ , and refracted The rate nd is 1.55~2.3.

According to a seventeenth aspect, the high refractive index glass of the first aspect, wherein the content of B ₂ O ₃ is more preferably from 0 to 3% by mass.

According to a eighteenth aspect, the high refractive index glass of the first invention, wherein the content of MgO is more preferably from 0 to 3% by mass.

According to a nineteenth aspect, the high refractive index glass of the first invention, wherein the content of ZrO ₂ +TiO ₂ is more preferably from 1% by mass to 20% by mass.

According to a twentieth aspect, the high refractive index glass of the first invention is preferably formed by a down-draw method. Here, the "down-draw method" includes an overflow down-draw method, a flow-down pull-down method, a redraw method, and the like.

<Second invention>

As a result of intensive studies, the present inventors have found that the above technical problem can be solved by setting the glass composition range within a predetermined range, and is proposed as the second invention. In other words, the high refractive index glass of the second aspect of the invention is characterized in that it contains 30% to 60% of SiO ₂ , 0 to 15% of B ₂ O ₃ , and 0 to 15% of Al as a glass composition. ₂ O ₃ , 0~10% Li ₂ O, 0~10% Na ₂ O, 0~10% K ₂ O, 20%~60% MgO+CaO+SrO+BaO+ZnO, 0.0001%~ 20% TiO ₂ , 0-20% ZrO ₂ , 0-10% La ₂ O ₃ + Nb ₂ O ₅ , and the refractive index nd is 1.55-2.3. Here, "MgO+CaO+SrO+BaO+ZnO" means the total amount of MgO, CaO, SrO, BaO, and ZnO. "La ₂ O ₃ + Nb ₂ O ₅ " means the total amount of La ₂ O ₃ and Nb ₂ O ₅ . The "refractive index nd" can be measured using a refractive index measuring instrument, for example, a rectangular parallelepiped sample of 25 mm × 25 mm × about 3 mm, and then a temperature range of (annealing point Ta + 30 ° C) to (strain point Ps - 50 ° C) Annealing treatment was carried out at a cooling rate of 0.1 ° C/min, and then the immersion liquid having the refractive index nd matching was infiltrated between the glass, and was measured by using a refractive index measuring instrument KPR-200 manufactured by Kalnour. The "annealing point Ta" means a value measured in accordance with the method described in ASTM C338-93. The "strain point Ps" is a value measured in accordance with the method described in ASTM C336-71.

The high refractive index glass according to the second aspect of the invention contains 30% to 60% of SiO ₂ , 0 to 15% of B ₂ O ₃ , 0 to 15% of Al ₂ O ₃ , and 20% to 60% of MgO + CaO + SrO + BaO+ZnO, 0.0001%~20% TiO ₂ , 0-20% ZrO ₂ . In this way, the refractive index nd can be increased while the devitrification resistance is improved.

High refractive index glass of the second invention comprises 0 to 10% of _{La 2 O 3 + Nb 2 O} 5. As a result, the raw material cost can be reduced, and the devitrification resistance or acid resistance can be easily improved.

The high refractive index glass of the second invention contains 0 to 10% of Li ₂ O, 0 to 10% of Na ₂ O, and 0 to 10% of K ₂ O. As a result, the acid resistance is improved, and the alkali component is eluted in the etching process using an acid, and the glass is less likely to be cloudy. Further, the etching process using an acid is included in a manufacturing process of an organic EL display or the like, and if the acid resistance of the glass plate is low, the glass plate is eroded and clouded during the etching process. When the glass plate is turbid, the transmittance of the glass plate is lowered, and it is difficult to achieve high definition of the display.

The refractive index nd of the high refractive index glass of the second invention is 1.55 to 2.3. As a result, it is easy to match the refractive index nd of the organic light-emitting element or the transparent conductive film, and the light emitted from the organic light-emitting element can be efficiently output to the outside.

Second, the high refractive index glass according to the second aspect of the invention preferably contains, as a glass composition, 35% to 60% of SiO ₂ , 0 to 15% of B ₂ O ₃ , and 0 to 15% by mass%. Al ₂ O ₃ , 0 to 10% Li ₂ O, 0% to 10% Na ₂ O, 0 to 10% K ₂ O, 20% to 60% MgO+CaO+SrO+BaO+ZnO, 0.0001%~20% TiO ₂ , 0.0001%~20% ZrO ₂ , 0~10% La ₂ O ₃ +Nb ₂ O ₅ , and the refractive index nd is 1.55~2.3.

Third, the high refractive index glass of the second aspect of the invention preferably contains, as a glass composition, 35% to 60% of SiO ₂ , 0 to 15% of B ₂ O ₃ , and 0 to 15% by mass%. Al ₂ O ₃ , 0 to 1% Li ₂ O, 0 to 1% Na ₂ O, 0 to 1% K ₂ O, 0 to 1% Li ₂ O+Na ₂ O+K ₂ O, 20%~50% MgO+CaO+SrO+BaO+ZnO, 0.1~35% BaO, 0.0001%~20% TiO ₂ , 0.0001%~20% ZrO ₂ , 0~10% La ₂ O ₃ +Nb ₂ O ₅ and the refractive index nd is 1.55 to 2.3. Here, "Li ₂ O+Na ₂ O+K ₂ O" means the total amount of Li ₂ O, Na ₂ O, and K ₂ O.

Fourth, the high refractive index glass of the second aspect of the invention preferably contains 1% by mass or more of B ₂ O ₃ .

Fifth, the high refractive index glass of the second aspect of the invention preferably contains 1% by mass or more of MgO.

Sixth, the high refractive index glass of the second invention is preferably plate-shaped. In this way, it is easy to apply to substrates of various elements such as an organic EL display, an organic EL illumination, and an organic thin film solar cell. Here, the "plate shape" is not limited to be defined, but includes a film shape having a small thickness, for example, a film-shaped glass provided along a column, and a glass having a concavo-convex shape.

7. The high refractive index glass of the second invention, preferably having a liquidus viscosity of 10 ^3.0 dPa. s above. In organic EL illumination or the like, since the surface smoothness of the glass plate is slightly different, the current density changes when a current is applied, and there is a problem that illuminance is uneven. Further, in order to improve the surface smoothness of the glass sheet, if the surface of the glass is polished, there is a problem that the processing cost is improved. Therefore, when the liquidus viscosity is in the above range, the glass sheet can be easily formed by an overflow down-draw method or the like, and as a result, it is easy to produce a glass sheet having excellent surface smoothness even without being polished. Here, the "liquid phase viscosity" refers to a value obtained by measuring the viscosity of the glass at a liquidus temperature by a platinum ball pulling method. "Liquid phase temperature" means that the glass powder which is passed through a 30 mesh (500 μm ) standard sieve and left on a 50 mesh (300 μm ) sieve is placed in a platinum boat and maintained in a temperature gradient oven for 24 hours. Thereafter, the value obtained by measuring the temperature of crystallization was measured. The "overflow down-draw method" means that the molten glass is allowed to overflow from both sides of the heat-resistant groove-like structure, and the overflowed molten glass is merged at the lower end of the groove-like structure, and is drawn downward to form a glass plate. method.

Eighth, the high refractive index glass of the second invention is preferably formed by a floating method or a downdraw method. Here, the "down pull method" includes the overflow down method, under the orifice Rafa and so on.

According to a ninth aspect, the high refractive index glass of the second aspect of the invention preferably has an unpolished surface on at least one side, and the surface roughness Ra of the surface is 10 Å or less. Here, "surface roughness Ra" means a value measured by a method based on JIS B0601:2001.

According to the first invention and the second invention described above, it is possible to provide a rare metal oxide (particularly, La ₂ O ₃ , Nb ₂ O ₅ , Gd ₂ O ₃ ) in a small amount, and to form an organic light-emitting element or a transparent electrode film. A high refractive index glass having a refractive index nd matching and good resistance to devitrification.

<First Embodiment>

The high refractive index glass according to the embodiment of the first invention (hereinafter referred to as the first embodiment) has a glass composition and contains 0 to 10% of B ₂ O ₃ and 0.001% to 35% as a mass %. SrO, 0.001%~30% ZrO ₂ +TiO ₂ , 0~10% La ₂ O ₃ +Nb ₂ O ₅ , mass ratio BaO/SrO is 0~40, mass ratio SiO ₂ /SrO is 0.1~40 . The reason for limiting the content range of each component as described above will be described below. In the following description of the range of contents, % means mass% unless otherwise specified.

The content of B ₂ O ₃ is preferably 0 to 10%. When the content of B ₂ O ₃ is increased, the refractive index nd or Young's modulus is liable to lower. Therefore, a suitable upper limit range of B ₂ O ₃ is 8% or less, 5% or less, 4% or less, 3% or less, less than 2%, 1% or less, and particularly less than 1%.

The content of SrO is preferably 0.001% to 35%. Among the alkaline earth metal oxides, SrO is a compound having a large effect of suppressing devitrification and increasing the refractive index nd. Minute. However, when the content of SrO is increased, the refractive index nd, the density, and the coefficient of thermal expansion become high, or the composition of the glass composition is unbalanced, and the devitrification resistance is likely to be lowered. Therefore, a suitable upper limit range of SrO is 30% or less, 25% or less, 20% or less, 15% or less, 12% or less, 10% or less, and particularly 8% or less. A suitable lower limit range of SrO is 0.01% or more, 0.1% or more, 1% or more, 2% or more, 3% or more, 3.5% or more, and particularly 4% or more.

The content of TiO ₂ + ZrO ₂ is preferably 0.001% to 30%. When the content of TiO ₂ +ZrO ₂ is increased, the devitrification resistance is liable to lower, or the density or thermal expansion coefficient is too high. On the other hand, if the content of TiO ₂ +ZrO ₂ is decreased, the refractive index nd is liable to lower. Therefore, a suitable upper limit range of TiO ₂ + ZrO ₂ is 25% or less, 20% or less, 18% or less, 15% or less, 14% or less, and particularly 13% or less. A suitable lower limit range of TiO ₂ +ZrO ₂ is 0.01% or more, 0.5% or more, 1% or more, 3% or more, 5% or more, 6% or more, and particularly 7% or more.

The content of TiO ₂ is preferably 0 to 30%. TiO ₂ is a component that increases the refractive index nd. However, if the content of TiO ₂ is increased, the density or thermal expansion coefficient becomes too high, or the devitrification resistance is liable to lower, or the transmittance tends to decrease. Therefore, a suitable upper limit range of TiO ₂ is 25% or less, 15% or less, 12% or less, and particularly 8% or less. A suitable lower limit range of TiO ₂ is 0.001% or more, 0.01% or more, 0.5% or more, 1% or more, and particularly 3% or more.

Content of ZrO ₂ is preferably 0 to 30%. ZrO ₂ is a component which has a good effect of increasing the refractive index nd and improving the viscosity in the vicinity of the liquidus temperature. However, if the content of ZrO ₂ is increased, the density may become too high or the devitrification resistance may be easily lowered. Therefore, a suitable upper limit range of ZrO ₂ is 15% or less, 10% or less, 7% or less, and particularly 6% or less. A suitable lower limit range of ZrO ₂ is 0.001% or more, 0.01% or more, 0.5% or more, 1% or more, 2% or more, and particularly 3% or more.

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 refractive index nd tends to be high. However, if the content is more than 10%, the composition of the glass composition is unbalanced, the devitrification resistance is lowered, or the raw material cost is increased. The cost of manufacturing glass is increased. In particular, in applications such as lighting, inexpensive glass is required, and thus the increase in raw material cost is not good. Therefore, a suitable lower limit range of La ₂ O ₃ + Nb ₂ O ₅ is 9% or less, 8% or less, 5% or less, 3% or less, 2% or less, 1% or less, 0.5% or less, and particularly preferably 0.1% or less. .

La ₂ O ₃ is a component that increases the refractive index nd. When the content of La ₂ O ₃ is increased, the devitrification resistance is liable to lower, and the density and thermal expansion coefficient are too high. Therefore, the content of La ₂ O ₃ is preferably 10% or less, 9% or less, 8% or less, 5% or less, 2% or less, 1% or less, 0.5% or less, or particularly 0.1% or less.

Nb ₂ O ₅ is a component that increases the refractive index nd. When the content of Nb ₂ O ₅ is increased, the devitrification resistance is liable to lower, and the density and thermal expansion coefficient are too high. Therefore, the content of Nb ₂ O ₅ is preferably 10% or less, 9% or less, 8% or less, 5% or less, 2% or less, 1% or less, 0.5% or less, or particularly 0.1% or less.

The mass ratio (La ₂ O ₃ + Nb ₂ O ₅ ) / (ZrO ₂ + TiO ₂ ) is preferably 0 to 30. When the mass ratio (La ₂ O ₃ +Nb ₂ O ₅ )/(ZrO ₂ +TiO ₂ ) is larger, the refractive index nd can be increased while suppressing the decrease in the devitrification resistance, but if the value is too large, the glass is too large. The components of the composition are unbalanced, the resistance to devitrification is lowered, or the cost of raw materials becomes too high. Therefore, a suitable upper limit range of the mass ratio (La ₂ O ₃ + Nb ₂ O ₅ ) / (ZrO ₂ + TiO ₂ ) is 20 or less, 10 or less, 5 or less, 2 or less, 1 or less, 0.1 or less, and particularly 0.01. the following.

The mass ratio is 0 to 40 for BaO/SrO. If the mass ratio is too large than BaO/SrO, the devitrification resistance is lowered, or the density or the thermal expansion coefficient becomes too high. On the other hand, if the mass ratio is too small, BaO/SrO is small, and the refractive index nd is lowered, or the composition of the glass composition is unbalanced, and the devitrification resistance is lowered. Therefore, a suitable upper limit range of the mass ratio BaO/SrO is 30 or less, 20 or less, 10 or less, 8 or less, or particularly 5 or less. A suitable lower limit range of the mass ratio BaO/SrO is 0.1 or more, 0.5 or more, 1 or more, 2.5 or more, and particularly preferably 3 or more.

Among the alkaline earth metal oxides, BaO is a component which does not lower the viscosity of the glass and raises the refractive index nd. The content of BaO is preferably from 0 to 40%. When the content of BaO is increased, the refractive index nd, density, and thermal expansion coefficient tend to become high. However, when the content of BaO exceeds 40%, the composition of the glass composition is unbalanced, and the devitrification resistance is liable to lower. Therefore, a suitable upper limit range of BaO is preferably 35% or less, 32% or less, 30% or less, 29.5% or less, 29% or less, or particularly 28% or less. However, if the content of BaO is decreased, it is difficult to obtain a desired refractive index nd, and it is difficult to ensure a high liquidus viscosity. Therefore, a suitable lower limit range of BaO is preferably 0.5% or more, 1% or more, 2% or more, 5% or more, 10% or more, 15% or more, 17% or more, 20% or more, 23% or more, particularly More than 25%.

The mass ratio is SiO ₂ /SrO of 0.1 to 40. If the mass ratio is excessively larger than SiO ₂ /SrO, the refractive index nd is liable to lower. On the other hand, if the mass ratio is too small as SiO ₂ /SrO, the devitrification resistance is likely to be lowered, or the density or the thermal expansion coefficient is too high. Therefore, a suitable upper limit range of the mass ratio SiO ₂ /SrO is 30 or less, 20 or less, 15 or less, 10 or less, 9 or less, or particularly 8 or less. A suitable lower limit range of the mass ratio SiO ₂ /SrO is 0.5 or more, 1 or more, 2 or more, 2.5 or more, and particularly preferably 3 or more.

The content of SiO ₂ is preferably from 0.1 to 60%. When the content of SiO ₂ is increased, the meltability and moldability are liable to lower, or the refractive index nd is likely to be lowered. Therefore, the content of SiO ₂ is preferably 55% or less, 53% or less, 52% or less, 50% or less, 49% or less, 48% or less, or particularly 45% or less. On the other hand, when the content of SiO ₂ is decreased, it is difficult to form a network structure of glass, and it is difficult to achieve vitrification. Moreover, the viscosity of the glass is excessively lowered, and it is difficult to ensure a high liquidus viscosity. Therefore, the content of SiO ₂ is preferably 3% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, and particularly 40% or more.

The content of Al ₂ O ₃ is preferably from 0 to 20%. When the content of Al ₂ O ₃ is increased, devitrified crystals are easily precipitated in the glass, the liquidus viscosity is liable to lower, and the refractive index nd is also likely to be lowered. Therefore, a suitable upper limit range of Al ₂ O ₃ is 15% or less, 10% or less, 8% or less, and particularly 6% or less. Further, when the content of Al ₂ O ₃ is decreased, the composition of the glass composition is unbalanced, and the glass is easily devitrified. Therefore, a suitable lower limit range of Al ₂ O ₃ is 0.1% or more, 0.5% or more, 1% or more, and particularly 3% or more.

The content of MgO is preferably from 0 to 10%. MgO is a component that increases the refractive index nd, Young's modulus, and strain point, and is also a component that lowers the high-temperature viscosity. However, if a large amount of MgO is added, there is an increase in liquidus temperature, a decrease in devitrification resistance, or a density or thermal expansion coefficient. Become too high. Therefore, a suitable upper limit range of MgO is 5% or less, 3% or less, 2% or less, 1.5% or less, 1% or less, and particularly 0.5% or less.

The content of CaO is preferably from 0 to 10%. If the content of CaO increases, it is dense The degree of thermal expansion and the coefficient of thermal expansion tend to be high; if the content of CaO is further excessive, the composition of the glass composition is unbalanced, and the devitrification resistance is liable to lower. Therefore, a suitable upper limit range of CaO is 9% or less, particularly 8.5% or less. Further, when the content of CaO is decreased, the meltability is lowered, or the Young's modulus is lowered, or the refractive index nd is likely to be lowered. Therefore, a suitable lower limit range of CaO is 0.5% or more, 1% or more, 2% or more, 3% or more, and particularly 4% or more.

The mass ratio (MgO+CaO)/SrO is preferably 0-20. When the mass ratio (MgO+CaO)/SrO is increased, the glass density can be lowered or the high temperature viscosity can be lowered while maintaining a high refractive index nd, but the liquidus temperature tends to become high and it is difficult to maintain high. Liquid viscosity. Therefore, a suitable upper limit range of the mass ratio (MgO+CaO)/SrO is 10 or less, 8 or less, 5 or less, 3 or less, 2 or less, or particularly 1 or less.

The content of ZnO is preferably from 0 to 12%. When the content of ZnO is increased, the density or thermal expansion coefficient tends to be too high, or the composition of the glass composition is unbalanced, the devitrification resistance is lowered, or the high-temperature viscosity is excessively lowered, and it is difficult to ensure a high liquidus viscosity. Therefore, a suitable upper limit range of ZnO is 8% or less, 4% or less, 2% or less, 1% or less, 0.5% or less, 0.1% or less, and particularly preferably 0.01% or less.

The content of La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ is preferably 0 to 10%. When the content of La ₂ O ₃ +Nb ₂ O ₅ +Gd ₂ O ₃ is increased, the refractive index nd tends to be high, but if the content is more than 10%, the composition of the glass composition is unbalanced and devitrification resistance is caused. Lowering, or rising raw material costs, leads to an increase in the manufacturing cost of glass. In particular, since inexpensive glass is required for applications such as lighting, the increase in raw material cost is not good. Therefore, a suitable lower limit range of La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ is 9% or less, 8% or less, 5% or less, 3% or less, 2% or less, 1% or less, or 0.5% or less. Especially below 0.1%.

The content of Gd ₂ O ₃ is preferably 0 to 10%. Gd ₂ O ₃ is a component that increases the refractive index, but if the content of Gd ₂ O ₃ is increased, the density or thermal expansion coefficient becomes too high, or the composition of the glass composition is unbalanced to lower the devitrification resistance or the high temperature viscosity. Too much reduction makes it difficult to ensure high liquid viscosity. Therefore, a suitable upper limit range of Gd ₂ O ₃ is 8% or less, 4% or less, 2% or less, 1% or less, 0.5% or less, 0.1% or less, and particularly preferably 0.01% or less.

The content of Li ₂ O+Na ₂ O+K ₂ O is preferably from 0 to 15%. Li ₂ O+Na ₂ O+K ₂ O is a component that lowers the viscosity of the glass and is a component that adjusts the coefficient of thermal expansion. However, if a large amount of Li ₂ O+Na ₂ O+K ₂ O is added, the viscosity of the glass is too high. It is difficult to ensure high liquid viscosity. Therefore, a suitable upper limit range of Li ₂ O+Na ₂ O+K ₂ O is 10% or less, 5% or less, 2% or less, 1.5% or less, 1% or less, 0.5% or less, and particularly preferably 0.1% or less.

As the clarifying agent, one to two or more selected from the group consisting of As ₂ O ₃ , Sb ₂ O ₃ , CeO ₂ , SnO ₂ , F, Cl, and SO ₃ may be added in an amount of 0 to 3%. However, from the viewpoint of the environment, it is preferred to control the use of As ₂ O ₃ , Sb ₂ O ₃ and F, particularly As ₂ O ₃ and Sb ₂ O ₃ as much as possible, and the content of each is preferably less than 0.1%. . In view of the above, as the clarifying agent, SnO ₂ , SO ₃ and Cl are preferred. In particular, the content of SnO ₂ is preferably 0% to 1%, 0.01% to 0.5%, particularly 0.05% to 0.4%. Further, the content of SnO ₂ +SO ₃ +Cl is preferably 0 to 1%, 0.001% to 1%, 0.01% to 0.5%, particularly 0.01% to 0.3%. Here, "SnO ₂ +SO ₃ +Cl" means the total amount of SnO ₂ , SO ₃ and Cl.

Although PbO is a component that lowers the viscosity of high temperature, from the environmental point of view, it is preferable to control the use of PbO as much as possible, and the PbO content is preferably 0.5%. Hereinafter, it is more preferably less than 1000 ppm (mass).

Although the Bi ₂ O ₃ is a component to reduce viscosity of the high temperature, but from the viewpoint of the environment, it is strongly preferred to use a control Bi ₂ O _3, and Bi ₂ O ₃ content is preferably 0.5% or less, more preferably is Less than 1000 ppm (mass).

It is of course possible to combine the suitable ranges of the respective components to construct a suitable glass composition range, but a particularly suitable glass composition range is as follows from the viewpoints of the refractive index nd, the devitrification resistance, the production cost, and the like.

(1) As a glass composition, it contains 20% to 50% of SiO ₂ , 0 to 8% of B ₂ O ₃ , 0 to 10% of CaO, 0.01% to 35% of SrO, and 0 to 30% by mass%. % BaO, 0~4% ZnO, 0.001%-20% ZrO ₂ +TiO ₂ , 0~3% La ₂ O ₃ +Nb ₂ O ₅ , 0~1% Li ₂ O+Na ₂ O +K ₂ O, and the mass ratio BaO/SrO is 0-20, the mass ratio SiO ₂ /SrO is 1-15, and the mass ratio (MgO+CaO)/SrO is 0-10.

(2) As a glass composition, it contains 35% to 50% SiO ₂ , 0 to 5% B ₂ O ₃ , 0 to 9% CaO, 1% to 35% SrO, 0 to 29 in terms of mass %. % BaO, 0~3% ZnO, 1%~15% ZrO ₂ +TiO ₂ , 0~0.1% La ₂ O ₃ +Nb ₂ O ₅ , 0~0.1% Li ₂ O+Na ₂ O +K ₂ O, and the mass ratio is 0 to 10 for BaO/SrO, 1 to 10 for mass ratio SiO ₂ /SrO, and 0 to 5 for mass ratio (MgO+CaO)/SrO.

(3) As a glass composition, it contains 35% to 50% SiO ₂ , 0 to 3% B ₂ O ₃ , 0 to 9% CaO, 2% to 20% SrO, 0 to 28 in terms of mass %. % of BaO, 0 ~ 1% of ZnO, 3% ~ 15% of _{ZrO 2 + TiO 2, 0 ~} 0.1% of _{La 2 O 3 + Nb 2 O} 5, 0 ~ 0.1% of Li ₂ O + Na ₂ O +K ₂ O, and the mass ratio is 0-8 for BaO/SrO, 2 to 10 for mass ratio SiO ₂ /SrO, and 0 to 3 for mass ratio (MgO+CaO)/SrO.

(4) As a glass composition, it contains 35% to 50% of SiO ₂ , 0 to 1% of B ₂ O ₃ , 0 to 8.5% of CaO, 4 to 15% of SrO, and 0 to 28 as mass %. % BaO, 0~0.1% ZnO, 6%~15% ZrO ₂ +TiO ₂ , 0~0.1% La ₂ O ₃ +Nb ₂ O ₅ , 0~0.1% Li ₂ O+Na ₂ O +K ₂ O, and the mass ratio is 0-8 for BaO/SrO, 2 to 10 for mass ratio SiO ₂ /SrO, and 0 to 3 for mass ratio (MgO+CaO)/SrO.

(5) As a glass composition, it contains 35% to 55% of SiO ₂ , 0 to 8% of B ₂ O ₃ , 0.001% to 35% of SrO, 0 to 12% of ZnO, and 0.001% by mass%. 30% ZrO ₂ +TiO ₂ , 0 to 5% La ₂ O ₃ +Nb ₂ O ₅ , 0% to 10% Li ₂ O+Na ₂ O+K ₂ O, and the mass ratio BaO/SrO is 0 ~20, the mass ratio SiO ₂ /SrO is 0.1-20, and the mass ratio (MgO+CaO)/SrO is 0-20.

(6) As a glass composition, it contains 35% to 55% of SiO ₂ , 0 to 5% of B ₂ O ₃ , 0 to 5% of MgO, 0 to 10% of ZrO ₂ , and 0 to 2 as a mass %. % Li ₂ O+Na ₂ O+K ₂ O, 0.1%-20% SrO, 0-30% BaO, 0.001%-15% TiO ₂ , 0-99% La ₂ O ₃ +Nb ₂ O ₅ +Gd ₂ O ₃ , and the mass ratio (La ₂ O ₃ +Nb ₂ O ₅ )/(ZrO ₂ +TiO ₂ ) is 0 to 5, and the mass ratio BaO/SrO is 0 to 10.

(7) As a glass composition, it contains 35% to 55% of SiO ₂ , 0 to 5% of B ₂ O ₃ , 0 to 5% of MgO, 0 to 10% of ZrO ₂ , and 0 to 2 as a mass %. % Li ₂ O+Na ₂ O+K ₂ O, 0.1%-20% SrO, 0-30% BaO, 0.001%-15% TiO ₂ , 0-99% La ₂ O ₃ +Nb ₂ O ₅ +Gd ₂ O ₃ , and the mass ratio (La ₂ O ₃ +Nb ₂ O ₅ )/(ZrO ₂ +TiO ₂ ) is 0 to 5, the mass ratio BaO/SrO is 0 to 10, and the mass ratio is SiO ₂ / The SrO is 0.1 to 10, and the mass ratio (MgO+CaO) / SrO is 0 to 2.

In the high refractive index glass of the first embodiment, the refractive index nd is 1.55 or more, preferably 1.58 or more, 1.6 or more, 1.63 or more, 1.65 or more, and particularly 1.66 or more. When the refractive index nd is less than 1.55, the reflectance at the ITO-glass interface becomes high, and light cannot be efficiently output. On the other hand, when the refractive index nd exceeds 2.3, the reflectance at the air-glass interface becomes high, and even if the surface of the glass is roughened, it is difficult to increase the light output efficiency. Therefore, the refractive index nd is preferably 2.3 or less, 2.2 or less, 2.1 or less, 2.0 or less, 1.9 or less, or particularly 1.75 or less.

In the high refractive index glass of the first embodiment, the liquidus temperature is preferably 1200 ° C or lower, 1150 ° C or lower, 1130 ° C or lower, 11 10 ° C or lower, 1090 ° C or lower, 1070 ° C or lower, or particularly 1050 ° C or lower. In addition, the liquid viscosity is preferably 10 ^3.0 dPa. Above s, 10 ^3.5 dPa. Above s, 10 ^3.8 dPa. s above, 10 ^4.0 dPa. Above s, 10 ^4.1 dPa. s above, 10 ^4.2 dPa. Above s, especially 10 ^4.3 dPa. s above. As a result, the glass is less likely to devitrify during molding, and the glass sheet can be easily formed by the floating method.

The high refractive index glass of the first embodiment is preferably plate-shaped. Further, the thickness is preferably 1.5 mm or less, 1.3 mm or less, 1.1 mm or less, 0.8 mm or less, 0.6 mm or less, 0.5 mm or less, 0.3 mm or less, or particularly 0.2 mm or less. The smaller the plate thickness, the higher the flexibility and the more easily the design of the lighting element is improved. However, if the thickness of the plate is extremely small, the glass plate is easily broken. Therefore, the sheet thickness is preferably 10 μm or more, particularly 30 μm or more.

The high refractive index glass of the first embodiment is preferably formed by a floating method. In this way, the unground surface quality can be manufactured inexpensively and in large quantities. Good glass plate.

In addition to the floating method, as a method of forming the glass sheet, for example, a down-draw method (overflow down-draw method, a flow-down method, a re-drawing method, or the like), a roll-out method, or the like may be employed.

In the high refractive index glass of the first embodiment, it is preferable to roughen one surface by HF etching, sand blasting or the like. The surface roughness Ra of the roughened surface is preferably 10 Å or more, 20 Å or more, 30 Å or more, and particularly 50 Å or more. When the roughened surface is used as the side in contact with the air such as organic EL illumination, the roughened surface is formed into a non-reflective structure, so that light emitted from the organic light-emitting layer is less likely to return to the organic light-emitting layer, and as a result, light can be improved. Output efficiency. Further, the surface of the glass can be imparted with a concave-convex shape by hot working such as repressing. In this way, a correct reflective structure can be formed on the surface of the glass. Regarding the uneven shape, the interval and depth can be adjusted while considering the refractive index nd. Further, a resin film having a concavo-convex shape can be attached to the surface of the glass.

When the atmospheric piezoelectric slurry process is used, the other surface can be uniformly roughened while maintaining the surface state of one of the surfaces. As a source of the atmospheric piezoelectric slurry process, it is preferred to use a gas containing F (for example, SF ₆ , CF ₄ ). In this way, a plasma containing an HF-based gas is generated, so that the efficiency of the roughening treatment is improved.

Further, in the case where a non-reflective structure is formed on the surface of the glass during molding, the same effect can be obtained without performing the roughening treatment.

In the high refractive index glass of the first embodiment, the density is preferably 5.0 g/cm ³ or less, 4.8 g/cm ³ or less, 4.5 g/cm ³ or less, 4.3 g/cm ³ or less, and 3.7 g/cm ^{3 .} or less, particularly 3.5g / cm ³ or less. In this way, the weight of the glass can be reduced and the weight of the component can be reduced. It should be noted that the "density" can be measured in accordance with the well-known Archimedes method.

In the high refractive index glass of the first embodiment, the coefficient of thermal expansion is preferably 30 × 10 ^-7 / ° C to 100 × 10 ^-7 / ° C, 40 × 10 ^-7 / ° C to 90 × 10 ^-7 / ° C, 60×10 ^-7 /°C~85×10 ^-7 /°C, 65×10 ^-7 /°C~80×10 ^-7 /°C, 68×10 ^-7 /°C~78×10 ^-7 /°C, especially 70 × 10 ^-7 / ° C ~ 78 × 10 ^-7 / ° C. In recent years, in organic EL illumination, organic EL elements, and dye-sensitized solar cells, a glass plate having flexibility has been demanded from the viewpoint of improving design factors. In order to increase the flexibility of the glass sheet, it is necessary to reduce the thickness of the glass sheet. However, in this case, if the thermal expansion coefficient of the glass sheet and the transparent conductive film such as ITO or FTO does not match, the glass sheet is easily warped. Further, when an organic EL display using an oxide TFT is produced, if the thermal expansion coefficients of the oxide TFT and the glass plate do not match, the glass plate may be warped or the oxide TFT film may be cracked. Therefore, when the coefficient of thermal expansion reaches the above range, it is easy to prevent the above-mentioned situation. Here, the "thermal expansion coefficient" means an average value in a temperature range of 30 ° C to 380 ° C, and can be measured, for example, using a dilatometer or the like.

In the high refractive index glass of the first embodiment, the strain point is preferably 630 ° C or higher, 650 ° C or higher, 670 ° C or higher, 690 ° C or higher, and particularly 700 ° C or higher. As a result, the glass is less likely to undergo heat shrinkage by the high-temperature heat treatment in the manufacturing process of the component. In particular, when an organic EL display is produced using an oxide TFT or the like, in order to stabilize the quality of the oxide TFT, heat treatment at about 600 ° C is required. However, when the strain point is specified as described above, the glass can be reduced in the heat treatment. Heat shrinkage.

In the high refractive index glass of the first embodiment, 10 ^2.5 dPa. The temperature under s is preferably 1400 ° C or lower, 1350 ° C or lower, 1300 ° C or lower, 1250 ° C or lower, and particularly 1200 ° C or lower. In this way, since the meltability is improved, it is easy to obtain a glass excellent in foam quality, and the production efficiency of the glass sheet is improved.

In the high refractive index glass of the first embodiment, 10 ^4.0 dPa. The temperature under s is 1250 ° C or less, 1200 ° C or less, 1150 ° C or less, 1110 ° C or less, and particularly 1060 ° C or less. As a result, in the molding by the floating method, the molding temperature can be lowered. As a result, it is possible to achieve low-temperature operation, and the life of the refractory used in the molded portion is prolonged, and the manufacturing cost of the glass sheet is easily lowered.

A method for producing a high refractive index glass according to the first embodiment is exemplified: first, a glass raw material is mixed to obtain a desired glass composition, and a glass batch is produced. Then, the glass batch is melted and clarified, and then the resulting molten glass is formed into a desired shape. Thereafter, annealing treatment is performed as needed to process into a desired shape.

Further, the glass plate for an illumination device according to the first aspect of the invention is characterized in that, as a glass composition, 0.1% to 60% of SiO ₂ and 0 to 10% of B ₂ O _{3 are} contained by mass%. 0.001%~35% SrO, 0~40% BaO, 0.001%~30% ZrO ₂ +TiO ₂ , 0%~10% La ₂ O ₃ +Nb ₂ O ₅ , and the refractive index nd is 1.55 ~2.3. In addition, the glass plate for organic EL illumination according to the embodiment of the present invention contains 0.1% to 60% of SiO ₂ and 0 to 10% of B ₂ O ₃ as a glass composition. 0.001%~35% SrO, 0~40% BaO, 0.001%~30% ZrO ₂ +TiO ₂ , 0%~10% La ₂ O ₃ +Nb ₂ O ₅ , and the refractive index nd is 1.55 ~2.3. Further, the glass plate for an organic EL display according to the first aspect of the invention is characterized in that the glass composition contains 0.1% to 60% of SiO ₂ and 0 to 10% of B ₂ O ₃ as a mass %. 0.001%~35% SrO, 0~40% BaO, 0.001%~30% ZrO ₂ +TiO ₂ , 0%~10% La ₂ O ₃ +Nb ₂ O ₅ , and the refractive index nd is 1.55 ~2.3. The technical features of the glass plate for an illumination device, the glass plate for an organic EL illumination, and the glass plate for an organic EL display are substantially the same as those of the high refractive index glass described in the first embodiment, and thus detailed description thereof will be omitted.

Example 1

Hereinafter, an embodiment of the first invention will be described in detail. It should be noted that the following embodiments are merely illustrative. The first invention is not limited to the following examples.

Tables 1 to 4 show examples of the first invention (sample Nos. 1 to 19).

First, the glass raw materials were mixed so as to have the glass compositions described in Tables 1 to 4, and then the obtained glass batch was supplied to a glass melting furnace and melted at 1,500 to 1,600 ° C for 4 hours. Next, the obtained molten glass is poured onto a carbon plate to form The plate shape is followed by a predetermined annealing treatment. Finally, various characteristics were evaluated for the obtained glass plate.

Density is a value measured according to the well-known Archimedes method.

The coefficient of thermal expansion is a value obtained by measuring an average coefficient of thermal expansion at 30 ° C to 380 ° C using a dilatometer. Measuring sample use Cylindrical sample of 5 mm × 20 mm (end processing was performed by R).

The strain point Ps is a value measured in accordance with the method described in ASTM C336-71. It should be noted that the higher the strain point Ps, the higher the heat resistance.

The annealing point Ta and the softening point Ts are values measured in accordance with the method described in ASTM C338-93.

High temperature viscosity 10 ^4.0 dPa. s, 10 ^3.0 dPa. s and 10 ^2.5 dPa. The temperature in s is a value measured by a platinum ball pulling method. In addition, the lower the temperature, the more excellent the meltability.

The liquidus temperature TL means that the glass powder which has passed through a 30 mesh (500 μm ) standard sieve and left on a 50 mesh (300 μm ) sieve is placed in a platinum boat and kept in a temperature gradient furnace for 24 hours. The value obtained by crystallization of the temperature. Further, the liquidus viscosity log ₁₀ ηTL is a value obtained by measuring the viscosity of the glass at the liquidus temperature by a platinum ball pulling method. In addition, the higher the liquidus viscosity and the lower the liquidus temperature, the more excellent the devitrification resistance and the moldability.

The refractive index nd means that a rectangular parallelepiped sample of 25 mm × 25 mm × about 3 mm is first produced, and then the temperature range of (annealing point Ta + 30 ° C) to (strain point Ps - 50 ° C) is performed at a cooling rate of 0.1 ° C / min. After the annealing treatment, the immersion liquid having the refractive index nd matching was infiltrated into the glass, and the value was measured by using a refractive index measuring instrument KPR-2000 manufactured by Shimadzu Corporation.

Example 2

The glass raw material was mixed to _obtain the glass composition described in the sample No. 3, and then the obtained glass batch was placed in a continuous furnace and melted at a temperature of 1500 ° C to 1600 ° C. Then, the obtained molten glass was molded by a floating method to obtain a glass plate having a thickness of 0.5 mm.

The glass raw material was mixed so as to reach the glass composition described in the sample No. 4, and then the obtained glass batch was placed in a continuous furnace and melted at a temperature of 1500 ° C to 1600 ° C. Then, the obtained molten glass was molded by a floating method to obtain a glass plate having a thickness of 0.5 mm.

The glass raw material is mixed so as to reach the glass composition described in the sample No. 6, and then the obtained glass batch is put into a continuous furnace, melted at a temperature of 1500 ° C to 1600 ° C, and then the obtained molten glass is obtained by a floating method. Forming was carried out to obtain a glass plate having a thickness of 0.5 mm.

<Second Embodiment>

The high refractive index glass according to the embodiment of the second invention (hereinafter referred to as the second embodiment) has a glass composition of 30% to 60% of SiO ₂ and 0% to 15% as a glass composition. B ₂ O ₃ , 0% to 15% Al ₂ O ₃ , 0% to 10% Li ₂ O, 0% to 10% Na ₂ O, 0% to 10% K ₂ O, 20% to 60 % MgO + CaO + SrO + BaO + ZnO, 0.0001% ~ 20% TiO ₂ , 0% ~ 20% ZrO ₂ , 0% ~ 10% La ₂ O ₃ + Nb ₂ O ₅ . The reason for limiting the content range of each component as described above will be described below. In addition, in the description of the content range of each component, unless otherwise indicated, % shows the mass %.

The content of SiO ₂ is 30 to 60%. When the content of SiO ₂ is increased, the meltability and moldability are liable to lower, and the refractive index nd is also likely to be lowered. Therefore, the upper limit of the content of SiO ₂ is 60% or less, preferably 50% or less, 48% or less, 45% or less, and particularly 43% or less. On the other hand, when the content of SiO ₂ is decreased, it is difficult to form a glass network structure, and it is difficult to achieve vitrification. In addition, the viscosity of the glass is also too low, and it is difficult to ensure a high liquid viscosity, and the acid resistance is also liable to decrease. Therefore, the lower limit of the content of SiO ₂ is 30% or more, preferably 35% or more, 38% or more, and particularly 40% or more.

The content of B ₂ O ₃ is 0 to 15%. When the content of B ₂ O ₃ is increased, the Young's modulus is liable to lower, and the strain point is also liable to lower. Moreover, the balance of the composition of the glass composition is impaired, the devitrification resistance is liable to be lowered, and the acid resistance is also liable to decrease. Therefore, the upper limit of the content of B ₂ O ₃ is 15% or less, preferably 10% or less, 8% or less, and particularly 6% or less. On the other hand, if the content of B ₂ O ₃ is decreased, the viscosity of the glass liquid phase is liable to lower. Therefore, a suitable lower limit content of B ₂ O ₃ is 0.1% or more, 0.5% or more, 1% or more, 1.5% or more, 2% or more, 3% or more, and particularly 4% or more.

The mass ratio B ₂ O ₃ /SiO _{2 is} preferably 0 to 1. When the mass ratio is larger than B ₂ O ₃ /SiO ₂ , it is difficult to ensure a high liquid phase viscosity, and chemical resistance is also likely to be lowered. Accordingly, the mass ratio of B ₂ O ₃ / SiO ₂ proper upper limit range of 1 or less, 0.5 or less, 0.2 or less, 0.15 or less, particularly 0.13 or less. On the other hand, if the mass ratio is smaller than B ₂ O ₃ /SiO ₂ , the balance of the composition of the glass composition is impaired, and the devitrification resistance is liable to lower. Therefore, a suitable lower limit range of the mass ratio B ₂ O ₃ /SiO ₂ is 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, and particularly 0.10 or more.

The content of Al ₂ O ₃ is 0 to 15%. When the content of Al ₂ O ₃ is too large, the balance of the composition of the glass composition is impaired, and the devitrification resistance is liable to lower. Acid resistance is also easy to reduce. Therefore, the upper limit of the content of Al ₂ O ₃ is 15% or less, preferably 10% or less, 8% or less, and particularly 6% or less. On the other hand, when the content of Al ₂ O ₃ is decreased, the viscosity of the glass is excessively lowered, and it is difficult to ensure a high liquid phase viscosity. Therefore, a suitable lower limit content of Al ₂ O ₃ is 0.5% or more, 1% or more, 2% or more, and particularly 4% or more.

The content of Li ₂ O is 0 to 10%. When the content of Li ₂ O is increased, the viscosity of the liquid phase is liable to lower, and the strain point is also liable to lower. Further, in an etching process using an acid, since the alkaline component is eluted, the glass is liable to become cloudy. Therefore, the upper limit of the content of Li ₂ O is 10% or less, preferably 8% or less, 5% or less, 4% or less, 3% or less, less than 2%, 1% or less, and particularly less than 1%. Contains no Li ₂ O. Here, "substantially free of Li ₂ O" means a case where the content of Li ₂ O in the glass composition is less than 1000 ppm (mass).

The content of Na ₂ O is 0 to 10%. When the content of Na ₂ O is increased, the viscosity of the liquid phase is liable to lower, and the strain point is also liable to decrease. Further, in an etching process using an acid, since the alkaline component is eluted, the glass is liable to become cloudy. Therefore, the upper limit of the content of Na ₂ O is 10% or less, preferably 8% or less, 5% or less, 4% or less, 3% or less, less than 2%, 1% or less, and particularly less than 1%. Contains no Na ₂ O. Here, "substantially free of Na ₂ O" means a case where the content of Na ₂ O in the glass composition is less than 1000 ppm (mass).

The content of K ₂ O is 0 to 10%. When the content of K ₂ O is increased, the viscosity of the liquid phase is liable to lower, and the strain point is also liable to lower. Further, in an etching process using an acid, since the alkaline component is eluted, the glass is liable to become cloudy. Therefore, the upper limit of the content of K ₂ O is 10% or less, preferably 8% or less, 5% or less, 4% or less, 3% or less, less than 2%, 1% or less, and particularly less than 1%. free of K ₂ O. Here, "substantially free of K ₂ O" means a case where the content of K ₂ O in the glass composition is less than 1000 ppm by mass.

The content of Li ₂ O+Na ₂ O+K ₂ O is preferably 0 to 10%. When the content of Li ₂ O+Na ₂ O+K ₂ O is increased, the viscosity of the liquid phase is liable to lower, and the strain point is also liable to decrease. Further, in an etching process using an acid, since the alkaline component is eluted, the glass is liable to become cloudy. Therefore, the upper limit of the content of Li ₂ O+Na ₂ O+K ₂ O is 10% or less, 8% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, and particularly less than 1%. It is desirable to be substantially free of Li ₂ O+Na ₂ O+K ₂ O. Here, "substantially free of Li ₂ O+Na ₂ O+K ₂ O" means a case where the content of Li ₂ O+Na ₂ O+K ₂ O in the glass composition is less than 1000 ppm by mass.

The content of MgO is preferably 0 to 20%. MgO is a component that increases the refractive index nd, Young's modulus, and strain point, and is also a component that lowers the high-temperature viscosity. However, if a large amount of MgO is contained, there is an increase in liquidus temperature, a decrease in devitrification resistance, or a density or thermal expansion. The coefficient becomes too high. Therefore, a suitable upper limit content of MgO is 20% or less, 10% or less, and particularly 6% or less. On the other hand, when the content of MgO is decreased, the meltability is lowered, or the Young's modulus is lowered, or the refractive index nd is likely to be lowered. Therefore, a suitable lower limit content of MgO is 0.1% or more, 0.5% or more, 1% or more, 1.5% or more, 2% or more, and particularly 3% or more.

The content of CaO is preferably from 0 to 15%. When the content of CaO is increased, the density and the coefficient of thermal expansion tend to be high, and the balance of the composition of the glass composition is also impaired, and the devitrification resistance is liable to lower. Therefore, a suitable upper limit content of CaO is 15% or less, 13% or less, 11% or less, 9.5% or less, and particularly 8% or less. On the other hand, if the content of CaO is decreased, the meltability is lowered, or the Young's modulus is lowered, or The refractive index nd is easily lowered. Therefore, a suitable lower limit content of CaO is 0.5% or more, 1% or more, and particularly 2% or more.

The content of SrO is preferably 0 to 25%. When the content of SrO is increased, the refractive index nd, the density, and the coefficient of thermal expansion are likely to be high, and the balance of the composition of the glass composition is also impaired, and the devitrification resistance is liable to lower. Therefore, a suitable upper limit content of SrO is 25% or less, 18% or less, 14% or less, and particularly 12% or less. On the other hand, when the content of SrO is decreased, the meltability is liable to lower, and the refractive index nd is also likely to be lowered. Therefore, a suitable lower limit content of SrO is 0.1% or more, 0.5% or more, 1% or more, 2% or more, 5% or more, 7% or more, and particularly 9% or more.

Among the alkaline earth metal oxides, BaO is a component which does not lower the viscosity of the glass and raises the refractive index nd, and the content thereof is preferably 0.1% to 60%. When the content of BaO is increased, the refractive index nd, the density, and the coefficient of thermal expansion tend to be high, and the balance of the composition of the glass composition is also impaired, and the devitrification resistance is liable to lower. Therefore, the suitable upper limit content of BaO is 60% or less, 53% or less, 48% or less, 44% or less, 40% or less, 39% or less, 36% or less, 35% or less, 34% or less, and particularly 33% or less. . On the other hand, if the content of BaO is decreased, it is difficult to obtain a desired refractive index nd, and it is also difficult to secure a high liquidus viscosity. Therefore, a suitable upper limit content of BaO is 0.1% or more, 1% or more, 2% or more, 5% or more, 10% or more, 15% or more, 20% or more, 23% or more, and particularly 25% or more.

The content of ZnO is preferably 0 to 20%. ZnO is a component that increases the refractive index nd and the strain point, and is also a component that lowers the high-temperature viscosity. However, if ZnO is added in a large amount, the liquidus temperature rises to lower the devitrification resistance, or the density or thermal expansion coefficient becomes too high. After that. Therefore, the appropriate upper limit content of ZnO is 20% or less, 10% or less, 5% or less, 3% or less, and particularly preferably 1% or less.

The content of MgO+CaO+SrO+BaO+ZnO is 20%~60%. When the content of MgO+CaO+SrO+BaO+ZnO is increased, the density and the coefficient of thermal expansion tend to be high, and the composition of the glass composition is degraded, and the devitrification resistance is liable to lower. Therefore, the upper limit of the content of MgO+CaO+SrO+BaO+ZnO is 60% or less, preferably 55% or less, 50% or less, 48% or less, and particularly 45% or less. On the other hand, if the content of MgO+CaO+SrO+BaO+ZnO is decreased, the glass becomes unstable. Therefore, the lower limit of the content of MgO+CaO+SrO+BaO+ZnO is 20% or more, preferably 30% or more, 35% or more, and particularly 40% or more.

TiO ₂ is a component that increases the refractive index nd. The content of TiO ₂ is 0.0001% to 20%. However, if the content of TiO ₂ is increased, the balance of the composition of the glass composition is impaired, and the devitrification resistance is liable to lower. In addition, the transmittance is also reduced, and when applied to an organic EL display, there is a possibility that the luminous efficiency is lowered. Therefore, the upper limit of the content of TiO ₂ is 20% or less, preferably 10% or less, 7% or less, and particularly 5% or less. On the other hand, when the content of TiO ₂ is decreased, it is difficult to obtain a desired refractive index nd. Therefore, the lower limit of the content of TiO ₂ is 0.0001% or more, preferably 0.001% or more, 0.01% or more, 0.02% or more, 0.05% or more, 0.1% or more, 1% or more, and particularly 2% or more.

ZrO ₂ is a component that increases the refractive index nd. The content of ZrO ₂ is 0 to 20%. However, if the content of ZrO ₂ is increased, the balance of the composition of the glass composition is impaired, and the devitrification resistance is liable to lower. Therefore, the upper limit of the content of ZrO ₂ is 20% or less, preferably 10% or less, 7% or less, and particularly 5% or less. On the other hand, when the content of ZrO ₂ is decreased, it is difficult to obtain a desired refractive index nd. Therefore, a suitable lower limit content of ZrO ₂ is 0.0001% or more, preferably 0.001% or more, 0.01% or more, 0.02% or more, 0.05% or more, 0.1% or more, 1% or more, and particularly 2% or more.

La ₂ O ₃ is a component that increases the refractive index nd. The content of La ₂ O ₃ is preferably 0 to 10%. When the content of La ₂ O ₃ is increased, the density and the coefficient of thermal expansion are liable to become high, and devitrification resistance or acid resistance is also likely to be lowered. In addition, the cost of raw materials increases, and the manufacturing cost of the glass sheet is likely to increase. Therefore, a suitable upper limit content of La ₂ O ₃ is 10% or less, 5% or less, 3% or less, 2.5% or less, and particularly preferably 1% or less.

Nb ₂ O ₅ is a component that increases the refractive index nd. The content of Nb ₂ O ₅ is preferably 0 to 10%. When the content of Nb ₂ O ₅ is increased, the density and the coefficient of thermal expansion are liable to become high, and the devitrification resistance is also liable to lower. In addition, the cost of raw materials increases, and the manufacturing cost of the glass sheet is likely to increase. Therefore, a suitable upper limit content of Nb ₂ O ₅ is 10% or less, 5% or less, 3% or less, and particularly preferably 1% or less.

The content of Gd ₂ O ₃ is preferably 0 to 10%. Gd ₂ O ₃ is a component that increases the refractive index nd. However, if the content of Gd ₂ O ₃ is increased, the density or coefficient of thermal expansion may become too high, or the composition of the glass composition may be unbalanced to lower the devitrification resistance, or the high temperature viscosity may be too low to ensure high liquid viscosity. . Therefore, a suitable upper limit content of Gd ₂ O ₃ is 10% or less, 5% or less, 3% or less, and particularly preferably 1% or less.

La ₂ O ₃ + Nb ₂ O ₅ content is 0 to 10%. When the content of La ₂ O ₃ + Nb ₂ O ₅ is increased, the density and the coefficient of thermal expansion are likely to be high, the devitrification resistance is likely to be lowered, and it is difficult to ensure a high liquid phase viscosity. In addition, the cost of raw materials increases, and the manufacturing cost of the glass sheet is likely to increase. Therefore, the upper limit of the content of La ₂ O ₃ + Nb ₂ O ₅ is 10% or less, preferably 8% or less, 5% or less, 3% or less, 1% or less, 0.5% or less, and particularly preferably 0.1% or less.

The content of the rare metal oxide is preferably from 0 to 10% in terms of the total amount. When the content of the rare metal oxide increases, the density and the coefficient of thermal expansion tend to be high, and the devitrification resistance or acid resistance is liable to be lowered, and it is difficult to ensure a high liquid phase viscosity. In addition, the cost of raw materials increases, and the manufacturing cost of the glass sheet is likely to increase. Therefore, a suitable upper limit content of the rare metal oxide is 10% or less, 5% or less, 3% or less, and particularly preferably 1% or less.

In addition to the above ingredients, the following ingredients may be added.

As the clarifying agent, one to two or more selected from the group consisting of As ₂ O ₃ , Sb ₂ O ₃ , CeO ₂ , SnO ₂ , F, Cl, and SO ₃ may be added in an amount of 0 to 3%. However, from the viewpoint of the environment, it is preferred to control the use of As ₂ O ₃ , Sb ₂ O ₃ and F as much as possible, and the content of each is preferably less than 0.1%. In view of the above, as the clarifying agent, SnO ₂ , SO ₃ , Cl, and CeO ₂ are preferable.

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

The content of SO ₃ is preferably 0 to 1%, 0 to 0.5%, 0.001% to 0.1%, 0.005% to 0.1%, 0.01% to 0.1%, particularly 0.01% to 0.05%. Glauber's salt can be used as an introduction material for SO ₃ . It is also possible to use a raw material containing sulfuric acid.

The content of Cl is preferably 0 to 1%, 0.001% to 0.5%, particularly 0.01% to 0.4%.

The content of SnO ₂ +SO ₃ +Cl is preferably 0 to 1%, 0.001% to 1%, 0.01% to 0.5%, particularly 0.01% to 0.3%. Here, "SnO ₂ +SO ₃ +Cl" means the total amount of SnO ₂ , SO ₃ and Cl.

The content of CeO ₂ is preferably 0 to 6%. When the content of CeO ₂ is increased, the devitrification resistance is liable to lower. Therefore, a suitable upper limit content of CeO ₂ is 6% or less, 5% or less, 3% or less, 2% or less, and particularly preferably 1% or less. On the other hand, if CeO _{2 is} decreased, the effect as a clarifying agent is insufficient. Therefore, a suitable lower limit content of CeO ₂ is 0.001% or more, 0.005% or more, 0.01% or more, 0.05% or more, and particularly 0.1% or more.

PbO is a component that lowers the viscosity of high temperature, but from the viewpoint of the environment, it is preferable to control the use of PbO as much as possible. The content of PbO is preferably 0.5% or less, and it is desirable to be substantially free of PbO. Here, "substantially free of PbO" means a case where the content of PbO in the glass composition is less than 1000 ppm by mass.

By combining the appropriate ranges of the ingredients, a suitable range of glass composition can be constructed. Among them, a suitable glass composition range is as follows.

(1) Calculated by mass%, containing 30% to 60% of SiO ₂ , 0% to 15% of B ₂ O ₃ , 0% to 15% of Al ₂ O ₃ , 0% to 10% of Li ₂ O, 0%~10% Na ₂ O, 0%~10% K ₂ O, 20%~60% MgO+CaO+SrO+BaO+ZnO, 0.1%~20% TiO ₂ , 0%~20% ZrO ₂ , 0%~10% La ₂ O ₃ + Nb ₂ O ₅ ;

(2) Calculated in mass %, containing 35% to 45% SiO ₂ , 2% to 8% B ₂ O ₃ , 4% to 8% Al ₂ O ₃ , 1% to 8% Li ₂ O, 0~5% Na ₂ O, 0~8% K ₂ O, 30%~48% MgO+CaO+SrO+BaO+ZnO, 1%~7% TiO ₂ , 0.1%~5% ZrO ₂ , 0~5% La ₂ O ₃ + Nb ₂ O ₅ .

In the high refractive index glass of the second embodiment, the refractive index nd is 1.55 or more, preferably 1.58 or more, 1.60 or more, and particularly 1.63 or more. When the refractive index nd is less than 1.55, light is not efficiently outputted due to reflection at the interface of the transparent conductive film-glass plate. On the other hand, if the refractive index nd is more than 2.3, the reflectance at the air-glass plate interface becomes high, even if the surface of the glass is roughened It is also difficult to output light to the outside. Therefore, the refractive index nd is 2.3 or less, preferably 2.2 or less, 2.1 or less, 2.0 or less, 1.9 or less, and particularly 1.75 or less.

In the high refractive index glass of the second embodiment, the density is preferably 5.0 g/cm ³ or less, 4.8 g/cm ³ or less, 4.5 g/cm ³ or less, 4.3 g/cm ³ or less, and 3.7 g/cm ^{3 .} Hereinafter, it is 3.5 g/cm ³ or less, especially 3.4 g/cm ³ or less. In this way, the weight of the component can be achieved.

In the high refractive index glass of the second embodiment, the thermal expansion coefficient at 30 ° C to 380 ° C is preferably 45 × 10 ^-7 / ° C to 110 × 10 ^-7 / ° C, 50 × 10 ^-7 / ° C to 100 ×10 ^-7 /°C, 60×10 ^-7 /°C~95×10 ^-7 /°C, 65×10 ^-7 /°C~90×10 ^-7 /°C, 65×10 ^-7 /°C~85×10 ^-7 / ° C, especially 67 × 10 ^-7 / ° C ~ 80 × 10 ^-7 / ° C. In recent years, in organic EL devices and the like, the flexibility of the glass sheet may be imparted from the viewpoint of improving design elements. In order to increase the flexibility of the glass sheet, it is necessary to reduce the thickness of the glass sheet, but in this case, if the coefficient of thermal expansion of the glass sheet and the transparent conductive film does not match, the glass sheet is easily warped. Therefore, when the coefficient of thermal expansion at 30 ° C to 380 ° C reaches the above range, it is easy to prevent the above situation.

In the high refractive index glass of the second embodiment, the strain point is preferably 600 ° C or higher, particularly 630 ° C or higher. In an element such as an organic thin film solar cell, when a transparent conductive film is formed, the higher the processing is performed at a high temperature, the more transparent and low-resistance film can be formed. However, the high refractive index glass to date has insufficient heat resistance, so that it is difficult to have both transparency and low electrical resistance. Therefore, when the strain point reaches the above range, in an element such as an organic thin film solar cell, transparency and low electric resistance can be achieved, and at the same time, heat shrinkage of the glass hardly occurs by heat treatment in the manufacturing process of the element.

In the high refractive index glass of the second embodiment, 10 ^2.5 dPa. The temperature under s is preferably 1450 ° C or lower, 1400 ° C or lower, 1350 ° C or lower, 1300 ° C or lower, 1250 ° C or lower, and particularly 1200 ° C or lower. As a result, the meltability is improved, so that the production efficiency of the glass is improved.

In the high refractive index glass of the second embodiment, the liquidus temperature is preferably 1200 ° C or less, 1150 ° C or less, 1130 ° C or less, 1110 ° C or less, 1090 ° C or less, 1070 ° C or less, 1050 ° C or less, and 1040 ° C or less. , below 1000 ° C, especially below 980 ° C. In addition, the liquid viscosity is preferably 10 ^3.5 dPa. Above s, 10 ^3.8 dPa. s above, 10 ^4.0 dPa. s above, 10 ^4.2 dPa. Above s, 10 ^4.4 dPa. Above s, 10 ^4.6 dPa. Above s, 10 ^4.8 dPa. Above s, especially 10 ^5.0 dPa. s above. As a result, the glass is not easily devitrified during molding, and the glass sheet can be easily formed by a floating method or an overflow down-draw method.

The high refractive index glass of the second embodiment is preferably plate-shaped. Further, the thickness (in the case of a plate shape means a plate thickness) is preferably 1.5 mm or less, 1.3 mm or less, 1.1 mm or less, 0.8 mm or less, 0.6 mm or less, 0.5 mm or less, 0.3 mm or less, or 0.2 mm or less. Especially 0.1mm or less. The smaller the thickness, the higher the flexibility, and it is easy to produce an illumination element having excellent design properties. However, if the thickness is extremely reduced, the glass is easily broken. Therefore, the thickness is preferably 10 μm or more, particularly 30 μm or more.

When the high refractive index glass of the second embodiment has a plate shape, it is preferable to have an unpolished surface on at least one surface (in particular, the entire effective surface of at least one surface is not polished). The theoretical strength of the original glass is very high, but often even stresses far below the theoretical strength can cause damage to the glass. This is because the Griffith microcrack is produced on the glass surface in a post-forming process, such as a polishing process. The reason for the small defects of the Griffith flaw. Therefore, when the surface of the glass is not polished, the original mechanical strength of the glass is not easily damaged, so that the glass is not easily broken. Further, since the polishing process can be simplified or omitted, the manufacturing cost of the glass plate can be reduced.

In the high refractive index glass of the second embodiment, the surface roughness Ra of the unpolished surface is preferably 10 Å or less, 5 Å or less, 3 Å or less, or particularly 2 Å or less. When the surface roughness Ra is more than 10 Å, the quality of the transparent conductive film formed on the surface is lowered, and it is difficult to obtain uniform light emission.

The high refractive index glass of the second embodiment is preferably formed by a down-draw method, in particular, an overflow down-draw method. In this way, it is possible to manufacture a glass plate having an unpolished lower surface quality. The reason for this is that when the overflow down-draw method is employed, the surface to be the surface is not in contact with the groove-shaped refractory, and is formed in a state of a free surface. The structure or material of the groove-like structure is not particularly limited as long as it can achieve a desired size or surface accuracy. Further, in order to perform the stretch forming to the lower side, the method of applying a force to the molten glass is not particularly limited. For example, a method in which a heat-resistant roller having a sufficiently large width is rotated in a state of being in contact with molten glass for stretching may be employed, and a plurality of pairs of heat-resistant rollers may be brought into contact only with the vicinity of the end faces of the molten glass. To perform the stretching method. Furthermore, in addition to the overflow down-draw method, as the down-draw method, the flow hole down-draw method can also be employed. In this way, it is easy to produce a glass plate having a small thickness. Here, the "flow hole down-draw method" refers to a method in which a molten glass is drawn downward from a slightly rectangular gap and formed into a glass sheet to form a glass sheet.

The high refractive index glass of the second embodiment is preferably formed by a floating method. In this way, a large glass plate can be produced inexpensively and in a large amount.

In addition to the above-described forming method, for example, a re-drawing method, a floating method, a roll pressing method, or the like can be employed.

In the high refractive index glass of the second embodiment, it is preferable to roughen one surface by HF etching, sand blasting or the like. The surface roughness Ra of the roughened surface is preferably 10 Å or more, 20 Å or more, 30 Å or more, and particularly 50 Å or more. When the roughened surface is used as the contact side with the air such as the organic EL illumination, the roughened surface is formed into a non-reflective structure, so that light emitted from the organic light-emitting layer is less likely to return to the organic light-emitting layer, and as a result, light can be improved. Output efficiency. Further, it is possible to impart a concave-convex shape to the surface of the glass (for example, hot working such as re-pressing). In this way, a correct reflective structure can be formed on the surface of the glass. The interval and depth of the uneven shape can be adjusted while considering the refractive index nd. Further, a resin film having a concavo-convex shape can be attached to the surface of the glass.

Further, when the roughening treatment is performed by the atmospheric piezoelectric slurry process, the surface of one of the surfaces can be maintained, and the other surface can be uniformly roughened. Further, as a source of atmospheric pressure plasma process, it is preferable to use the F-containing gas (e.g. SF _6, CF _4). As a result, a plasma containing an HF-based gas is generated, so that the efficiency of the roughening treatment is improved.

Further, a method of forming an uneven shape on one surface during molding is also preferable. In this case, it is not necessary to separately perform an independent roughening treatment, and the efficiency of the roughening treatment is improved.

Next, a method of manufacturing the high refractive index glass of the second embodiment will be exemplified. First, a glass batch is prepared by mixing glass raw materials in such a manner as to achieve a desired glass composition. This glass batch is then melted, clarified, and then formed into the desired shape. After that, it is processed into a desired shape.

Example 3

Hereinafter, an embodiment of the second invention will be described in detail. It should be noted that the following embodiments are merely illustrative. The second invention is not limited to the following examples.

Tables 5 to 12 show examples (sample No. 20 to No. 55) and comparative examples (sample No. 56) of the second invention.

First, the glass raw materials were mixed to obtain the glass compositions described in Tables 5 to 12, and then the obtained glass batches were supplied to a glass melting furnace and melted at 1500 ° C for 4 hours. Next, the obtained molten glass is poured onto a carbon plate to form a plate shape, and then subjected to a predetermined annealing treatment. Finally, various characteristics were evaluated for the obtained glass plate.

The refractive index nd means that a rectangular parallelepiped sample of 25 mm × 25 mm × about 3 mm is first produced, and then the temperature range of (annealing point Ta + 30 ° C) to (strain point Ps - 50 ° C) is performed at a cooling rate of 0.1 ° C / min. After the annealing treatment, the immersion liquid having the refractive index nd matching was infiltrated into the glass, and the value was measured by using a refractive index measuring instrument KPR-2000 manufactured by Shimadzu Corporation.

Density is a value measured according to the well-known Archimedes method.

The coefficient of thermal expansion is a value obtained by measuring an average coefficient of thermal expansion at 30 ° C to 380 ° C using a dilatometer. Measuring sample use Cylindrical sample of 5 mm × 20 mm (end processing was performed by R).

The strain point Ps is a value measured in accordance with the method described in ASTM C336-71. It should be noted that the higher the strain point Ps, the higher the heat resistance.

Annealing point Ta. The softening point Ts is a value measured in accordance with the method described in ASTM C338-93.

High temperature viscosity 10 ^4.0 dPa. s, 10 ^3.0 dPa. s, 10 ^2.5 dPa. s, and 10 ^2.0 dPa. The temperature under s is a value measured by a platinum ball pulling method. In addition, the lower the temperature, the more excellent the meltability.

The liquidus temperature TL means that the glass powder which has passed through a 30 mesh (500 μm ) standard sieve and left on a 50 mesh (300 μm ) sieve is placed in a platinum boat and kept in a temperature gradient furnace for 24 hours. The value obtained by crystallization of the temperature. Further, the liquidus viscosity log ₁₀ ηTL is a value obtained by measuring the viscosity of the glass at the liquidus temperature by a platinum ball pulling method. In addition, the higher the liquidus viscosity and the lower the liquidus temperature, the more excellent the devitrification resistance and the formability.

The HCl resistance was evaluated by the following method. First, both surfaces of each glass sample were optically polished, and then a part of the glass sample was masked, and then the chemical liquid treatment was performed under the following conditions. After the chemical treatment, the mask was removed, and the difference between the mask portion and the eroded portion was measured using a surface roughness meter, and this value was used as the amount of erosion. The HCl resistance (erosion amount) was evaluated as follows: when the amount of erosion exceeds 20 μm , the evaluation is "x"; when the amount of erosion is 20 μm or less, the evaluation is "○". Regarding the HCl resistance (appearance), both surfaces of each glass sample were optically polished, and then the chemical liquid treatment was carried out under the following conditions, and then the surface of the glass sample was visually observed to become cloudy or rough, or cracked. The glass sample was evaluated as "x"; the glass sample which did not change was evaluated as "○".

The HCl resistance (amount of erosion) was treated by immersing in a 10% by mass aqueous solution of HCl at 80 ° C for 24 hours; the treatment condition of HCl resistance (appearance) was: immersing in a 10% by mass aqueous solution of HCl at 80 ° C for 24 hours. .

As can be seen from the table, Sample Nos. 20 to 55 contain substantially no basic components and rare metal oxides, and the refractive index nd is 1.623 or more, and the acid resistance is good. The liquidus viscosity of sample No. 20, No. 24, No. 27 to No. 37, No. 39, No. 43 to No. 45, and No. 47 to No. 55 was 10 ^3.4 dPa. s above. Further, in Sample Nos. 20 to No. 31, although the refractive index nd is high but the density is low, the weight of the element can be reduced. Further, since it has a thermal expansion coefficient similar to that of the transparent conductive film, it is expected to be a sample capable of suppressing warpage of the glass sheet. In addition, since samples No. 20 to No. 25 and No. 27 to No. 55 have high strain points, they are considered to be samples capable of suppressing heat shrinkage of the glass in the device manufacturing process. On the other hand, in the sample No. 56, since a large amount of rare metal oxide was contained in the glass composition, the density was high and the acid resistance was low.

As described above, the high refractive index glass of the present invention has a refractive index nd of 1.55 or more and a high liquid phase viscosity. Therefore, from the viewpoint of raw material cost, the rare metal oxide can be removed from the glass composition, and from the viewpoint of the environment, As ₂ O ₃ , Sb ₂ O ₃ or the like can be removed from the glass composition. Therefore, the high refractive index glass of the present invention is suitable for a substrate for an organic EL device, particularly a substrate for organic EL illumination. In addition, the high refractive index glass of the present invention can also be used as a cover for a flat panel display such as a liquid crystal display, a charge coupled device (CCD), or an image sensor such as a double contact type solid state imaging device (CIS). Slides, substrates for solar cells, etc.

Claims (32)

A high refractive index glass characterized by comprising, as a glass composition, 0 to 10% of B ₂ O ₃ , 0.001% to 35% of SrO, and 0.001% to 30% of ZrO ₂ +TiO ₂ , 0%~10% of La ₂ O ₃ +Nb ₂ O ₅ , mass ratio BaO/SrO is 0-40, mass ratio SiO ₂ /SrO is 0.1~40, and refractive index nd is 1.55~2.3. The high refractive index glass according to claim 1, wherein the high refractive index glass has a liquid viscosity of 10 ^3.0 dPa. s above. The high refractive index glass according to claim 1, wherein the high refractive index glass is in a plate shape. The high refractive index glass according to claim 3, wherein the high refractive index glass is formed by a floating method. The high refractive index glass according to claim 3, wherein the high refractive index glass has a temperature of 1050 ° C or less at 10 ⁴ dPa ‧ s. The high refractive index glass according to any one of the preceding claims, wherein the high refractive index glass has a strain point of 650 ° C or higher. The high refractive index glass according to any one of claims 1 to 5, wherein the high refractive index glass is used for a lighting element. The high refractive index glass of claim 7, wherein the high refractive index glass is used for organic EL illumination. The high refractive index glass according to any one of claims 1 to 5, wherein the high refractive index glass is used for an organic EL display. A high refractive index glass characterized by comprising, as a glass composition, 0 to 8% of B ₂ O ₃ , 0.001% to 35% of SrO, 0 to 12% of ZnO, and 0.001% to 30% by mass%. ZrO ₂ +TiO ₂ , 0 to 5% La ₂ O ₃ +Nb ₂ O ₅ , 0% to 10% Li ₂ O+Na ₂ O+K ₂ O, and the mass ratio BaO/SrO is 0-20 The mass ratio of SiO ₂ /SrO is 0.1-20, the mass ratio (MgO+CaO)/SrO is 0-20, the refractive index nd is 1.58 or more, and the liquid viscosity is 10 ^3.5 dPa. Above s, the strain point is 670 ° C or more. A high refractive index glass characterized by comprising, as a glass composition, 10% to 50% of SiO ₂ , 0 to 8% of B ₂ O ₃ , 0 to 10% of CaO, and 0.001% to 35% by mass. % SrO, 0~30% BaO, 0~4% ZnO, 0.001%~30% ZrO ₂ +TiO ₂ , 0~5% La ₂ O ₃ +Nb ₂ O ₅ , 0~2% Li ₂ O+Na ₂ O+K ₂ O, and mass ratio BaO/SrO is 0-20, mass ratio SiO ₂ /SrO is 1-15, mass ratio (MgO+CaO)/SrO is 0-20, refractive index Nd is 1.6 or more, and the liquid viscosity is 10 ^4.0 dPa. Above s, the strain point is 670 ° C or more. A glass plate for a lighting element, characterized in that, as a glass composition, it is composed of 0.1% to 60% of SiO ₂ , 0 to 10% of B ₂ O ₃ , 0.001% to 35% of SrO, and 0% by mass%. 40% BaO, 0.001% to 30% ZrO ₂ + TiO ₂ , 0% to 10% La ₂ O ₃ + Nb ₂ O ₅ , and the refractive index nd is 1.55 to 2.3. A glass plate for organic EL illumination, characterized in that, as a glass composition, it is calculated by mass%, including 0.1% to 60% of SiO ₂ , 0 to 10% of B ₂ O ₃ , and 0.001% to 35% of SrO, 0. ~40% BaO, 0.001% to 30% ZrO ₂ +TiO ₂ , 0% to 10% La ₂ O ₃ +Nb ₂ O ₅ , and the refractive index nd is 1.55 to 2.3. A glass plate for an organic EL display, characterized in that, as a glass composition, it is calculated by mass%, including 0.1% to 60% of SiO ₂ , 0 to 10% of B ₂ O ₃ , and 0.001% to 35% of SrO, 0. ~40% BaO, 0.001% to 30% ZrO ₂ +TiO ₂ , 0% to 10% La ₂ O ₃ +Nb ₂ O ₅ , and the refractive index nd is 1.55 to 2.3. A high refractive index glass characterized in that, as a glass composition, it is calculated by mass%, including 35% to 60% of SiO ₂ , 0 to 1.5% of Li ₂ O+Na ₂ O+K ₂ O, and 0.1% to 35. % SrO, 0 to 35% BaO, 0.001% to 25% TiO ₂ , 0 to 9% La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ , and the refractive index nd is 1.55 to 2.3. A high refractive index glass characterized in that, as a glass composition, it is calculated by mass%, including 35% to 60% of SiO ₂ , 0 to 1.5% of Li ₂ O+Na ₂ O+K ₂ O, and 0.1% to 20%. % SrO, 17% to 35% BaO, 0.01% to 20% TiO ₂ , 0 to 9% La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ , and the refractive index nd is 1.55 to 2.3. The high refractive index glass according to claim 15 or 16, wherein the content of B ₂ O ₃ is more from 0 to 3% by mass. The high refractive index glass according to claim 15 or 16, wherein the content of MgO is more than 0 to 3% by mass. The high refractive index glass according to claim 15 or 16, wherein the content of ZrO ₂ + TiO ₂ is more from 1% by mass to 20% by mass. The high refractive index glass of claim 15 or 16, wherein the high refractive index glass is in the form of a plate. The high refractive index glass according to claim 15 or 16, wherein the high refractive index glass has a liquid viscosity of 10 ^3.0 dPa·s or more. The high refractive index glass according to claim 15 or 16, wherein the high refractive index glass is formed by a floating method or a downdraw method. A high refractive index glass characterized by comprising, as a glass composition, 30% to 60% of SiO ₂ , 0% to 15% of B ₂ O ₃ , and 0% to 15% of Al ₂ O _{3 .} 0%~10% Li ₂ O, 0%~10% Na ₂ O, 0%~10% K ₂ O, 20%~60% MgO+CaO+SrO+BaO+ZnO, 0.0001%~ 20% TiO ₂ , 0% to 20% ZrO ₂ , 0% to 10% La ₂ O ₃ + Nb ₂ O ₅ , and the refractive index nd is 1.55 to 2.3. A high refractive index glass characterized by comprising, as a glass composition, 35% to 60% of SiO ₂ , 0% to 15% of B ₂ O ₃ , and 0% to 15% of Al ₂ O _{3 .} 0%~10% Li ₂ O, 0%~10% Na ₂ O, 0%~10% K ₂ O, 20%~60% MgO+CaO+SrO+BaO+ZnO, 0.0001%~ 20% TiO ₂ , 0.0001% to 20% ZrO ₂ , 0% to 10% La ₂ O ₃ + Nb ₂ O ₅ , and the refractive index nd is 1.55 to 2.3. A high refractive index glass characterized by comprising, as a glass composition, 35% to 60% of SiO ₂ , 0% to 15% of B ₂ O ₃ , and 0% to 15% of Al ₂ O _{3 .} 0~1% Li ₂ O, 0~1% Na ₂ O, 0~1% K ₂ O, 0~1% Li ₂ O+Na ₂ O+K ₂ O, 20%~50% MgO+CaO+SrO+BaO+ZnO, 0.1%~35% BaO, 0.0001%~20% TiO ₂ , 0.0001%~20% ZrO ₂ , 0%~10% La ₂ O ₃ +Nb ₂ O ₅ and the refractive index nd is 1.55 to 2.3. A high refractive index glass characterized by comprising, as a glass composition, 35% to 60% of SiO ₂ , 0% to 15% of B ₂ O ₃ , and 0% to 15% of Al ₂ O _{3 .} 0~1% Li ₂ O, 0~1% Na ₂ O, 0~1% K ₂ O, 0~1% Li ₂ O+Na ₂ O+K ₂ O, 20%~50% MgO+CaO+SrO+BaO+ZnO, 0.1%~35% BaO, 0.0001%~20% TiO ₂ , 0.0001%~20% ZrO ₂ , 0~2.5% La ₂ O ₃ , 0~8 % La ₂ O ₃ + Nb ₂ O ₅ and a refractive index nd of 1.55 to 2.3. The high refractive index glass according to any one of claims 23 to 26, which comprises 1% by mass or more of B ₂ O ₃ . The high refractive index glass according to any one of claims 23 to 26, which comprises 1% by mass or more of MgO. The high refractive index glass according to any one of claims 23 to 26, wherein the high refractive index glass is in a plate shape. The high refractive index glass according to any one of claims 23 to 26, wherein the high refractive index glass has a liquid viscosity of 10 ^3.0 dPa·s or more. The high refractive index glass according to any one of claims 23 to 26, wherein the high refractive index glass is formed by a floating method or a downdraw method. The high refractive index glass according to any one of claims 23 to 26, wherein the high refractive index glass includes an unpolished surface on at least one side, and the surface has a surface roughness Ra of 10 Å or less.