WO2014002932A1 - Glass substrate for organic el device and manufacturing method therefor - Google Patents

Abstract

This glass substrate for an organic EL device is characterized by having a compressive stress layer at the surface.

Description

Glass substrate for organic EL and method for producing the same

The present invention relates to a glass substrate for organic EL and a method for producing the same.

Mobile devices such as mobile phones, digital cameras, PDAs, solar cells and touch panel displays are widely used and tend to become increasingly popular in the future. These mobile devices are required to be thinner and lighter.

At present, an organic EL display is manufactured using a 0.7 mm or 0.5 mm thick glass substrate, a panel is assembled, and then the glass substrate is thinned to a thickness of 0.2 to 0.3 mm by etching or the like. The way to make it. However, when the glass substrate is thinned to a thickness of 0.2 to 0.3 mm, the mechanical strength of the glass substrate is lowered. In order to compensate for this decrease in mechanical strength, a structure in which a tempered glass substrate is disposed on the front surface of the display is employed.

As described above, in the organic EL device, in order to reduce the thickness of the glass substrate, the glass substrate was etched after the panel was assembled. However, since etching and the like are costly, there is a risk that the manufacturing cost of the organic EL device will increase.

When a tempered glass substrate is disposed on the front surface of the display, the thickness of the tempered glass substrate must be reduced in order to reduce the overall thickness. In this case, the tensile stress inside the tempered glass substrate is high. In order not to become too much, it is necessary to limit the compressive stress value and the stress depth of the compressive stress layer, and as a result, it becomes difficult to increase the mechanical strength of the tempered glass substrate. Therefore, it is difficult to achieve both the mechanical strength and the thinning of the organic EL device.

The present invention has been made in view of the above technical problem, and the technical problem is to devise a glass substrate capable of achieving both a reduction in thickness and an increase in strength without increasing the manufacturing cost of an organic EL device. That is.

As a result of various studies, the present inventor has found that the above technical problem can be solved by regulating the content of each component in the glass composition, and proposes the present invention. That is, the glass substrate for organic EL of the present invention has a compressive stress layer on the surface.

Secondly, the glass substrate for organic EL of the present invention contains, as a glass composition, 40% to 80% of SiO ₂ , 1 to 25% of Al ₂ O ₃ , and 0.5 to 20% of Na ₂ O as a glass composition. It is preferable. In addition, the glass substrate for organic EL of this invention contains crystallized glass etc. besides tempered glass.

Third, it is preferable that the glass substrate for organic EL of the present invention is chemically strengthened.

Fourthly, the glass substrate for organic EL of the present invention preferably has a compressive stress of the compressive stress layer of 100 MPa or more, a stress thickness of 10 μm or more, and an internal tensile stress of 200 MPa or less. Here, “compressive stress value of compressive stress layer” and “stress depth” are interference fringes observed when a sample is observed using a surface stress meter (for example, FSM-6000 manufactured by Toshiba Corporation). The value calculated from the number of and the interval. “Internal tensile stress” refers to the value calculated by the following formula 1.

(Formula 1)
Internal tensile stress = (compressive stress value x stress depth) / (plate thickness-stress depth x 2)

Fifth, the glass substrate for organic EL of the present invention preferably has an alkali barrier film formed on at least one surface. In this way, it becomes easy to prevent the situation where alkali ions diffuse into the semiconductor material formed in the heat treatment step. As a result, it becomes easy to apply the glass substrate containing an alkali metal oxide to an organic EL device like this invention.

Sixth, in the glass substrate for organic EL of the present invention, the thickness of the alkali barrier film is preferably 10 to 1000 nm.

Seventh, the method for producing a glass substrate for organic EL of the present invention is a glass containing, by mass%, SiO ₂ 40-80%, Al ₂ O ₃ 1-25%, Na ₂ O 0.5-20%. A glass raw material prepared to have a composition is melted and formed into a plate shape, and then subjected to an ion exchange treatment to form a compressive stress layer on the glass surface.

Eighth, the method for producing a glass substrate for organic EL of the present invention is preferably formed into a plate shape by a downdraw method. Ninthly, it is preferable that the manufacturing method of the glass substrate for organic EL of this invention shape | molds in plate shape with the overflow downdraw method.

The structural example at the time of producing an organic EL device using the glass substrate for organic EL of the present invention is shown. The structural example at the time of producing an organic EL device using the glass substrate for organic EL of the present invention is shown.

The glass substrate for organic EL according to the embodiment of the present invention is a tempered glass having a compressive stress layer on the surface. There are a physical strengthening method and a chemical strengthening method as a method for forming a compressive stress layer on the surface. In this embodiment, it is preferable to form the compressive stress layer by a chemical strengthening method. The chemical strengthening method is a method of introducing alkali ions having a large ion radius to the surface of the glass by performing an ion exchange treatment at a temperature below the strain point of the glass. If the compressive stress layer is formed by the chemical strengthening method, a desired mechanical strength can be obtained even if the plate thickness of the glass substrate is small. Furthermore, even if the tempered glass is cut after forming the compressive stress layer, unlike a physical strengthening method such as an air cooling strengthening method, it is not easily broken.

The glass substrate for organic EL of the present embodiment contains, as a glass composition, 40 to 80% of SiO ₂ , 1 to 25% of Al ₂ O _{3 and} 0.5 to 20% of Na ₂ O as a glass composition. The reason for limiting the glass composition in this way will be described below. In the following description, “%” indicates mass% unless otherwise specified.

SiO ₂ is a component that forms a network of glass. The content of SiO ₂ is preferably 40 to 80%, preferably 41 to 71%, preferably 42 to 66%, preferably 43 to 65%, preferably 44 to 63%, preferably 45 to 63%, preferably Is 50 to 59%, particularly preferably 55 to 58.5%. If the SiO ₂ content is too large, it will be difficult to melt and mold the glass, or the thermal expansion coefficient will be too low, making it difficult to match the thermal expansion coefficient with the surrounding materials. On the other hand, if the content of SiO ₂ is too small, it becomes difficult to vitrify. Moreover, a thermal expansion coefficient becomes high and the thermal shock resistance of glass tends to fall. From the above viewpoint, the upper limit of the content of SiO ₂ is preferably 80% or less, preferably 71% or less, preferably 70% or less, preferably 66% or less, preferably 65% or less, preferably 63% or less, preferably Is 60% or less, preferably 59% or less, preferably 58.5% or less, and particularly preferably 56% or less. The lower limit of the SiO ₂ content is preferably 40% or more, preferably 41% or more, preferably 42% or more, preferably 43% or more, preferably 44% or more, preferably 45% or more, preferably 50 % Or more, particularly preferably 55% or more.

Al ₂ O ₃ is a component that improves the ion exchange performance, and also has an effect of increasing the strain point and Young's modulus. The content of Al ₂ O ₃ is preferably 1 to 25%. When the content of Al ₂ O ₃ is too large, it is difficult to forming by the overflow down-draw method or the like is easily devitrified crystal glass deposition. In this case, the coefficient of thermal expansion becomes too low, making it difficult for the peripheral material and the coefficient of thermal expansion to match, and increasing the high-temperature viscosity, making it difficult to melt. On the other hand, when the content of Al ₂ O ₃ is too small, a possibility arises which can not exhibit a sufficient ion exchange performance. From the above viewpoint, the upper limit of the content of Al ₂ O ₃ is preferably 23% or less, preferably 21% or less, preferably 20% or less, preferably 19% or less, preferably 18% or less, preferably 17.5. % Or less, preferably 17% or less, particularly preferably 16.5% or less. Further, the lower limit of the content of Al ₂ O ₃ is preferably 3% or more, preferably 7.5% or more, preferably 8.5% or more, preferably 9% or more, preferably 10% or more, preferably 12 % Or more, preferably 13% or more, preferably 14% or more, preferably 15% or more, particularly preferably 16% or more. When emphasizing meltability, the content of Al ₂ O ₃ is preferably 15% or less.

Na ₂ O is an ion exchange component and a component that lowers the high temperature viscosity and improves the meltability and moldability. Na ₂ O is also a component that improves devitrification resistance. However, when the content of Na ₂ O is too large, the thermal expansion coefficient becomes too high, the thermal shock resistance is lowered, and it is difficult to match the thermal expansion coefficient with the surrounding materials. In this case, the strain point tends to be too low, or the balance of the glass composition is lacking, and the devitrification resistance tends to be lowered. On the other hand, if too small content of Na ₂ O, lowered the melting property, become too coefficient of thermal expansion is low, it tends to decrease the ion exchange performance. From the above viewpoint, the upper limit of the content of Na ₂ O is preferably 20% or less, preferably 19% or less, preferably 18% or less, preferably 17% or less, preferably 15% or less, particularly preferably 13% or less. It is. Further, the lower limit of the content of Na ₂ O is preferably 0.1% or more, preferably 3% or more, preferably 6% or more, preferably 7% or more, preferably 8% or more, preferably 10% or more, Particularly preferably, it is 12% or more. In the case where importance is attached to the consistency of the coefficient of thermal expansion with a device such as TFT rather than ion exchange performance, the content of Na ₂ O is preferably 12% or less, preferably 10% or less, preferably 8% or less, Particularly preferably, it is 6% or less.

In addition to the above components, for example, the following components may be added.

Li ₂ O is an ion-exchange component and a component that lowers the high-temperature viscosity and improves meltability and moldability. Li ₂ O is a component that improves the Young's modulus. Furthermore, Li ₂ O has a large effect of increasing the compressive stress value among alkali metal oxides. However, when the content of Li ₂ O is too large, and decreases the liquidus viscosity, it tends glass devitrified. In addition, the thermal expansion coefficient becomes too high, the thermal shock resistance is lowered, and it is difficult to match the thermal expansion coefficient with the surrounding materials. Furthermore, if the low-temperature viscosity is too low and stress relaxation is likely to occur, the compressive stress value may be lowered. Therefore, the content of Li ₂ O is preferably 0 to 3.5%, preferably 0 to 2%, preferably 0 to 1%, preferably 0 to 0.5%, preferably 0 to 0.1%. It is most preferable not to contain substantially, that is, to suppress to less than 0.01%.

K ₂ O has an effect of promoting ion exchange, and has a high effect of increasing the stress depth among alkali metal oxides. Moreover, it is a component which reduces a high temperature viscosity and improves a meltability and a moldability. K ₂ O is also a component that improves devitrification resistance. The content of K ₂ O is preferably 0 to 15%. When the content of K ₂ O is too large, the thermal expansion coefficient becomes high, or the thermal shock resistance is lowered, the peripheral material and the coefficient of thermal expansion is hardly consistent. Furthermore, there is a tendency that the strain point is excessively lowered, the balance of the glass composition is lacking, and the devitrification resistance is lowered. Therefore, the upper limit of the content of K ₂ O is preferably 12% or less, preferably 10% or less, preferably 9% or less, preferably 8% or less, preferably 7% or less, particularly preferably 6% or less. . Further, the lower limit of the content of K ₂ O is preferably 0.1 or more, preferably 0.5% or more, preferably 1% or more, preferably 2% or more, preferably 3% or more, preferably 4% or more. Particularly preferably, it is 4.5% or more.

If the total amount of the alkali metal oxide R ₂ O (R is one or more selected from Li, Na, K) becomes too large, the glass tends to be devitrified and the thermal expansion coefficient becomes too high. As a result, the thermal shock resistance is lowered, and the thermal expansion coefficient is difficult to match with the surrounding material. Further, there is a case where the total content of alkali metal oxides R ₂ O is too large, too lowered strain point, not obtain a high compression stress value. Furthermore, the viscosity in the vicinity of the liquidus temperature may decrease, and it may be difficult to ensure a high liquidus viscosity. Therefore, the total amount of R ₂ O is preferably 22% or less, preferably 20% or less, and particularly preferably 19% or less. On the other hand, if the total amount of R ₂ O is too small, the ion exchange performance and meltability may decrease. Therefore, the total amount of R ₂ O is preferably 8% or more, preferably 10% or more, preferably 13% or more, and particularly preferably 15% or more.

The value of (Na ₂ O + K ₂ O) / Al ₂ O ₃ is preferably 0.5 to 4, preferably 0.7 to 2, and preferably 0.8 to 1. The amount is preferably regulated to 6, 0.9 to 1.6, preferably 1 to 1.6, particularly preferably 1.2 to 1.6. When this value is increased, the low-temperature viscosity is excessively decreased, the ion exchange performance is decreased, the Young's modulus is decreased, the thermal expansion coefficient is excessively increased, and the thermal shock resistance is easily decreased. Moreover, when this value becomes large, the component balance of a glass composition will be impaired and it will become easy to devitrify glass. On the other hand, when this value is small, the meltability and devitrification resistance are liable to decrease.

The range of the mass ratio of K ₂ O / Na ₂ O is preferably 0-2. When the mass ratio of K ₂ O / Na ₂ O is changed, the compressive stress value and the stress depth can be changed. When it is desired to set a high compressive stress value, the mass ratio is preferably adjusted to be 0 to 0.3, particularly preferably 0 to 0.2. On the other hand, when it is desired to increase the stress depth or to form a deep compressive stress layer in a short time, the mass ratio is preferably 0.3 to 2, preferably 0.5 to 2, preferably 1 to. It is preferable to adjust to 2, preferably 1.2 to 2, particularly preferably 1.5 to 2. Here, the reason why the upper limit of the mass ratio is set to 2 is that if it exceeds 2, the glass composition is not balanced and the glass is easily devitrified.

For example, alkaline earth metal oxide R′O (R ′ is one or more selected from Mg, Ca, Sr, and Ba) is a component that can be added for various purposes. However, when the total amount of R′O increases, the density and thermal expansion coefficient increase and devitrification resistance decreases, and in addition, ion exchange performance tends to decrease. Therefore, the total amount of R′O is preferably 0 to 9.9%, preferably 0 to 8%, preferably 0 to 6, particularly preferably 0 to 5%. On the other hand, when it is desired to achieve a high strain point, the total amount of R′O is preferably controlled to 1 to 10%, preferably 2 to 9%, preferably 4 to 8%, particularly preferably 6 to 8%. Is good.

MgO is a component that lowers the viscosity at high temperature to increase the meltability and formability, and increases the strain point and Young's modulus. Among alkaline earth metal oxides, MgO has a great effect of improving ion exchange performance. The MgO content is preferably 0 to 6%. However, when the content of MgO increases, the density and thermal expansion coefficient increase, and the glass tends to devitrify. Therefore, the content of MgO is preferably 5% or less, preferably 4% or less, preferably 3% or less, preferably 2.5% or less, preferably 2% or less, particularly preferably 1.5% or less. . When introducing MgO, the content of MgO is preferably 0.1% or more, particularly preferably 1% or more.

CaO is a component that lowers the high-temperature viscosity to increase meltability and formability, and increases the strain point and Young's modulus. Among alkaline earth metal oxides, CaO has a great effect of improving ion exchange performance. The CaO content is preferably 0 to 10%. However, when the content of CaO is increased, the density and thermal expansion coefficient may be increased, the glass may be easily devitrified, and the ion exchange performance may be decreased. Therefore, the upper limit of the CaO content is preferably 9% or less, preferably 8% or less, preferably 7% or less, and particularly preferably 6% or less. On the other hand, the lower limit of the content of CaO is preferably 0.1% or more, preferably 1% or more, preferably 2% or more, preferably 4% or more, preferably 5% or more. In the case where introduction of CaO is avoided as much as possible, the CaO content is preferably 4% or less, preferably less than 2%, particularly preferably 0.9% or less.

SrO and BaO are components that lower the high-temperature viscosity to improve the meltability and moldability, and increase the strain point and Young's modulus. The contents of SrO and BaO are each preferably 0 to 3%. When the content of SrO or BaO increases, the ion exchange performance tends to decrease. Further, the density and the thermal expansion coefficient are increased, and the glass is easily devitrified. The content of SrO is preferably 2% or less, preferably 1.5% or less, preferably 1% or less, preferably 0.5% or less, preferably 0.2% or less, particularly preferably 0.1% or less. It is. The content of BaO is preferably 2.5% or less, preferably 2% or less, preferably 1% or less, preferably 0.8% or less, preferably 0.5% or less, preferably 0.2%. Hereinafter, it is particularly preferably 0.1% or less.

ZnO is a component that enhances ion exchange performance, and is particularly effective in increasing the compressive stress value. ZnO is also a component having an effect of reducing the high temperature viscosity without reducing the low temperature viscosity. The ZnO content is preferably 0 to 8%. However, if the ZnO content is increased, the glass is phase-divided, the devitrification resistance is lowered, and the density is increased. Therefore, the content is preferably 8% or less, preferably 6% or less, preferably Is 5% or less, preferably 4% or less, preferably 3% or less, preferably 2% or less, preferably 1% or less, particularly preferably less than 1%.

When the content (total amount) of SrO + BaO is regulated to 0 to 5%, the ion exchange performance can be improved more effectively. That is, since SrO and BaO have the effect | action which inhibits an ion exchange reaction as mentioned above, containing many of these components is disadvantageous when raising the mechanical strength of tempered glass. The content of SrO + BaO is preferably 0 to 3%, preferably 0 to 2.5%, preferably 0 to 2%, preferably 0 to 1%, preferably 0 to 0.2%, particularly preferably 0 to 0.1%.

When the value obtained by dividing the total amount of R′O by the total amount of R ₂ O increases, the tendency of the devitrification resistance to decrease appears. Therefore, the value of R′O / R ₂ O in mass fraction is preferably regulated to 0.5 or less, preferably 0.4 or less, particularly preferably 0.3 or less.

SnO ₂ has an effect of improving the ion exchange performance, particularly the compressive stress value. Therefore, it preferably contains 0.01 to 3%, preferably 0.01 to 1.5%, particularly preferably 0.1 to 1%. It is good to do. When the content of SnO ₂ increases, devitrification due to SnO ₂ occurs or the glass tends to be easily colored.

ZrO ₂ has the effect of significantly improving the ion exchange performance, increasing the Young's modulus and strain point, and lowering the high temperature viscosity. Further, since ZrO ₂ has an effect of increasing the viscosity in the vicinity of the liquid phase viscosity, the ion exchange performance and the liquid phase viscosity can be simultaneously increased by containing a predetermined amount. However, when the content of ZrO ₂ is too large, the devitrification resistance may be extremely lowered. Therefore, the content of ZrO ₂ is preferably 0 to 10%, preferably 0.001 to 10%, preferably 0.1 to 9%, preferably 0.5 to 8%, preferably 0.5 to 7%. %, Preferably 1 to 5%, particularly preferably 2.5 to 5%. In order to avoid the ZrO ₂ content as much as possible, the ZrO ₂ content is preferably less than 2%, preferably less than 1%, preferably less than 1%, preferably less than 0.5%, preferably less than 0. 1% or less, particularly preferably less than 0.1%.

B ₂ O ₃ has the effect of lowering the liquidus temperature, high temperature viscosity and density, and also has the effect of improving ion exchange performance, particularly the compressive stress value. Therefore, B ₂ O ₃ can be contained together with the above components. However, if the content is too large, there is a possibility that the surface may be burnt by ion exchange, the water resistance may be lowered, or the liquid phase viscosity may be lowered. . In this case, the stress depth tends to decrease. Therefore, the content of B ₂ O ₃ is preferably 0 to 6%, preferably 0 to 4%, preferably 0 to 3%, preferably 0 to 1%, preferably 0 to 0.8%, preferably It is 0 to 0.5%, particularly preferably 0 to 0.1%.

TiO ₂ is a component that has an effect of improving ion exchange performance. It also has the effect of reducing the high temperature viscosity. However, when there is too much the content, glass will color, devitrification resistance will fall, or a density will become high. In particular, when used as a display substrate, when the content of TiO ₂ is increased, the transmittance tends to change when the melting atmosphere or the raw material is changed. Therefore, in the process of bonding the glass substrate to the device using light such as ultraviolet curable resin, the ultraviolet irradiation conditions are likely to fluctuate, and stable production becomes difficult. Therefore, the content of TiO ₂ is preferably 10% or less, preferably 8% or less, preferably 6% or less, preferably 5% or less, preferably 4% or less, preferably 2% or less, preferably 0.7%. % Or less, preferably 0.5% or less, preferably 0.1% or less, particularly preferably 0.01% or less.

In the present embodiment, from the viewpoint of improving ion exchange performance, it is preferable to restrict ZrO ₂ and TiO ₂ to the above range, but a reagent may be used as the TiO ₂ source and the ZrO ₂ source, and impurities contained in the raw materials and the like May be introduced.

From the viewpoint of achieving both devitrification resistance and ion exchange performance, the content (total amount) of Al ₂ O ₃ + ZrO ₂ is preferably determined as follows. The content of Al ₂ O ₃ + ZrO ₂ is preferably more than 12%, preferably 13% or more, preferably 15% or more, preferably 17% or more, preferably 18% or more, preferably 19% or more. If it does in this way, it will become possible to improve ion exchange performance more effectively. However, when the content of Al ₂ O ₃ + ZrO ₂ is too high, devitrification resistance is extremely lowered. Therefore, the upper limit of the content of Al ₂ O ₃ + ZrO ₂ is preferably 28% or less, preferably 25% or less, preferably 23% or less, preferably 22% or less, and particularly preferably 21% or less.

P ₂ O ₅ is a component that enhances the ion exchange performance, and since the effect of increasing the stress depth is particularly great, its content is preferably 0 to 8%. However, when the content of P ₂ O ₅ is increased, the glass is phase-separated and the water resistance and devitrification resistance are liable to be lowered. Therefore, the upper limit of the content of P ₂ O ₅ is preferably 5% or less, preferably 4% or less, preferably 3% or less, particularly preferably 2% or less.

As a fining agent, 0.001 to 3% of one or more selected from the group of As ₂ O ₃ , Sb ₂ O ₃ , CeO ₂ , F, SO ₃ , and Cl may be added. However, As ₂ O ₃ and Sb ₂ O ₃ are preferably used as much as possible in consideration of the environment, and each content is less than 0.1%, particularly less than 0.01%, that is, substantially no content. Is preferred. CeO ₂ is a component that lowers the transmittance, and the content thereof is preferably less than 0.1%, particularly less than 0.01%, that is, it is preferably not substantially contained. F may lower the low temperature viscosity and may cause a decrease in compressive stress value. Therefore, it is preferable that the content of F is less than 0.1%, particularly less than 0.01%, that is, it is not substantially contained. Accordingly, preferred fining agents are SO ₃ and Cl, preferably one or both of SO ₃ and Cl, preferably 0.001 to 3%, preferably 0.001 to 1%, 0.01 to 0.5. %, Particularly preferably 0.05 to 0.4%.

Rare earth oxides such as Nd ₂ O ₃ and La ₂ O ₃ are components that increase the Young's modulus. However, the cost of the raw material itself is high, and if it is contained in a large amount, the devitrification resistance is lowered. Therefore, the content of the rare earth oxide is preferably 3% or less, preferably 2% or less, preferably 1% or less, preferably 0.5% or less, particularly 0.1% or less.

Transition metal elements such as Co and Ni that strongly color the glass are not preferable because they reduce the transmittance. In particular, when used in a display, if the content of the transition metal element is large, the visibility of the display tends to be lowered. Therefore, the content of the transition metal oxide is preferably 0.5% or less, preferably 0.1% or less, and particularly preferably 0.05%. Therefore, the amount of the raw material or cullet can be adjusted. desirable.

It is preferable to limit the oxide content of substances such as Pb and Bi to less than 0.1% in consideration of the environment.

In the glass substrate for organic EL of this embodiment, a suitable content range of each component can be appropriately selected to obtain a preferable glass composition range. Specific examples are shown below.
(1) By mass, SiO ₂ 40-71%, Al ₂ O ₃ 7.5-21%, Li ₂ O 0-2%, Na ₂ O 10-19%, K ₂ O 0-15%, MgO A glass composition containing 0 to 6%, CaO 0 to 6%, SrO 0 to 3%, BaO 0 to 3%, ZnO 0 to 8%, SnO ₂ 0.01 to 3%.
(2) By mass%, SiO ₂ 40-71%, Al ₂ O ₃ 7.5-21%, Li ₂ O 0-2%, Na ₂ O 10-19%, K ₂ O 0-15%, MgO A glass composition containing 0-6%, CaO 0-6%, SrO 0-3%, BaO 0-3%, ZnO 0-8%, SnO ₂ 0.01-3%, ZrO ₂ 0-10%.
(3) By mass%, SiO ₂ 40-71%, Al ₂ O ₃ 8.5-21%, Li ₂ O 0-1%, Na ₂ O 10-19%, K ₂ O 0-10%, MgO A glass composition containing 0 to 6%, CaO 0 to 6%, SrO 0 to 3%, BaO 0 to 3%, ZnO 0 to 8%, SnO ₂ 0.01 to 3%.
(4) By mass%, SiO ₂ 40 to 71%, Al ₂ O ₃ 8.5 to 21%, Li ₂ O 0 to 1%, Na ₂ O 10 to 19%, K ₂ O 0 to 10%, MgO A glass composition containing 0-6%, CaO 0-6%, SrO 0-3%, BaO 0-3%, ZnO 0-8%, SnO ₂ 0.01-3%, ZrO ₂ 0-10%.
(5) By mass%, SiO ₂ 40-71%, Al ₂ O ₃ 9-19%, B ₂ O ₃ 0-6%, Li ₂ O 0-2%, Na ₂ O 10-19%, K ₂ O 0-15%, MgO 0-6%, CaO 0-6%, SrO 0-3%, BaO 0-3%, ZnO 0-6%, SnO ₂ 0.1-1%, ZrO ₂ 0.001 A glass composition that is ˜10% and substantially free of As ₂ O ₃ and Sb ₂ O ₃ .
(6) By mass, SiO ₂ 40-71%, Al ₂ O ₃ 9-18%, B ₂ O ₃ 0-4%, Li ₂ O 0-2%, Na ₂ O 11-17%, K ₂ O 0-6%, MgO 0-6%, CaO 0-6%, SrO 0-3%, BaO 0-3%, ZnO 0-6%, SnO ₂ 0.1-1%, ZrO ₂ 0.001 A glass composition that is ˜10% and substantially free of As ₂ O ₃ and Sb ₂ O ₃ .
(7) By mass, SiO ₂ 40 to 63%, Al ₂ O ₃ 9 to 17.5%, B ₂ O ₃ 0 to 3%, Li ₂ O 0 to 0.1%, Na ₂ O 10 to 17 %, K ₂ O 0-7%, MgO 0-5%, CaO 0-4%, SrO + BaO 0-3%, SnO ₂ 0.01-2%, substantially As ₂ O ₃ and Sb ₂ O. ₃ , a glass composition having a mass fraction of (Na ₂ O + K ₂ O) / Al ₂ O ₃ of 0.9 to 1.6 and K ₂ O / Na ₂ O of 0 to 0.4.
(8) By mass%, SiO ₂ 40 to 71%, Al ₂ O ₃ 3 to 21%, Li ₂ O 0 to 2%, Na ₂ O 10 to 20%, K ₂ O 0 to 9%, MgO 0 to Glass composition containing 5%, TiO ₂ 0-0.5%, SnO ₂ 0.001-3%.
(9) By mass%, SiO ₂ 40-71%, Al ₂ O ₃ 8-21%, Li ₂ O 0-2%, Na ₂ O 10-20%, K ₂ O 0-9%, MgO 0- A glass composition containing 5%, TiO ₂ 0-0.5%, SnO ₂ 0.001-3% and substantially free of As ₂ O ₃ and Sb ₂ O ₃ .
(10) By mass%, SiO ₂ 40-65%, Al ₂ O ₃ 8.5-21%, Li ₂ O 0-1%, Na ₂ O 10-20%, K ₂ O 0-9%, MgO It contains 0 to 5%, TiO ₂ 0 to 0.5%, SnO ₂ 0.001 to 3%, and the value of (Na ₂ O + K ₂ O) / Al ₂ O ₃ is 0.7 to 2 in terms of mass fraction. A glass composition characterized by being substantially free of As ₂ O ₃ , Sb ₂ O ₃ and F.
(11) By mass, SiO ₂ 40 to 65%, Al ₂ O ₃ 8.5 to 21%, Li ₂ O 0 to 1%, Na ₂ O 10 to 20%, K ₂ O 0 to 9%, MgO It contains 0-5%, TiO ₂ 0-0.5%, SnO ₂ 0.01-3%, MgO + CaO + SrO + BaO 0-8%, and the value of (Na ₂ O + K ₂ O) / Al ₂ O ₃ by mass fraction Is a glass composition containing 0.9 to 1.7 and substantially free of As ₂ O ₃ , Sb ₂ O ₃ and F.
(12) By mass%, SiO ₂ 40 to 63%, Al ₂ O ₃ 9 to 19%, B ₂ O ₃ 0 to 3%, Li ₂ O 0 to 1%, Na ₂ O 10 to 20%, K ₂ O 0-9%, MgO 0-5%, TiO ₂ 0-0.1%, SnO ₂ 0.01-3%, ZrO ₂ 0.001-10%, MgO + CaO + SrO + BaO 0-8% The value of (Na ₂ O + K ₂ O) / Al ₂ O ₃ is 1.2 to 1.6 in terms of percentage, and is substantially free of As ₂ O ₃ , Sb ₂ O ₃ and F. Glass composition.
(13) By mass%, SiO ₂ 40 to 63%, Al ₂ O ₃ 9 to 17.5%, B ₂ O ₃ 0 to 3%, Li ₂ O 0 to 1%, Na ₂ O 10 to 20%, K ₂ O 0-9%, MgO 0-5%, TiO ₂ 0-0.1%, SnO ₂ 0.01-3%, ZrO ₂ 0.1-8%, MgO + CaO + SrO + BaO 0-8%, A glass composition having a mass fraction of (Na ₂ O + K ₂ O) / Al ₂ O ₃ of 1.2 to 1.6 and substantially not containing As ₂ O ₃ , Sb ₂ O ₃ and F.
(14) By mass%, SiO ₂ 40 to 59%, Al ₂ O ₃ 10 to 15%, B ₂ O ₃ 0 to 3%, Li ₂ O 0 to 0.1%, Na ₂ O 10 to 20%, Contains K ₂ O 0-7%, MgO 0-5%, TiO ₂ 0-0.1%, SnO ₂ 0.01-3%, ZrO ₂ 1-8%, MgO + CaO + SrO + BaO 0-8%, A glass composition having a ratio of (Na ₂ O + K ₂ O) / Al ₂ O ₃ of 1.2 to 1.6 and containing substantially no As ₂ O ₃ , Sb ₂ O ₃ and F.
(15) SiO ₂ 50 to 65%, Al ₂ O ₃ 12 to 19%, Li ₂ O 0 to 1%, Na ₂ O 12 to 18%, K ₂ O 0 to 8%, MgO 0 to 6%, CaO A glass composition containing 0 to 6%, SrO 0 to 1%, BaO 0 to 1%, ZnO 0 to 8%, SnO ₂ 0.01 to 3%.
(4) SiO ₂ 50 to 65%, Al ₂ O ₃ 16 to 25%, B ₂ O ₃ 0 to 1%, Na ₂ O 7 to 15%, K ₂ O 2 to 9%, MgO 2 to 5%, A glass composition containing 0-10% CaO, 0-1% SrO, 0-1% BaO, 0-0.5% TiO ₂ .
(16) SiO ₂ 50-60%, Al ₂ O ₃ 17-25%, B ₂ O ₃ 0-0.8%, Na ₂ O 7-15%, K ₂ O 4.5-6%, MgO 2 ~ 5%, CaO 0 ~ 10%, SrO 0 ~ 1%, BaO 0 ~ 1%, TiO ₂ 0 ~ 0.5%, ZrO ₂ 0 ~ 2%, ZnO 0 ~ 5%, Fe ₂ O ₃ 0 ~ Glass composition containing 1%, SnO ₂ 0.1-3%.
(17) SiO ₂ 50 to 56%, Al ₂ O ₃ 17 to 23%, B ₂ O ₃ 0 to 0.5%, Na ₂ O 8 to 12%, K ₂ O 4.5 to 6%, MgO 2 0.5-5%, CaO 4-8%, SrO 0-0.1%, BaO 0-0.1%, TiO ₂ 0-0.1%, ZrO ₂ 0-0.1%, ZnO 0-5 %, Fe ₂ O ₃ 0-0.1%, SnO ₂ 0.1-3%, As ₂ O ₃ 0-0.1%, Sb ₂ O ₃ 0-0.1% glass composition (18) SiO ₂ 50-70%, Al ₂ O ₃ 12-25%, B ₂ O ₃ 0-1%, Na ₂ O 10-13%, K ₂ O 4.5-9%, MgO 2-6%, CaO A glass composition containing 0 to 8%, SrO 0 to 1%, BaO 0 to 1%, TiO ₂ 0 to 0.1%.
(19) SiO ₂ 50-70%, Al ₂ O ₃ 12-25%, B ₂ O ₃ 0-0.1%, Na ₂ O 10-13%, K ₂ O 4.5-9%, MgO 2 ~ 6%, CaO 0 ~ 8%, SrO 0 ~ 1%, BaO 0 ~ 1%, TiO ₂ 0 ~ 0.1%, ZrO ₂ 0 ~ 2%, ZnO 0 ~ 1%, As ₂ O ₃ 0 ~ Glass composition containing 0.1%, Sb ₂ O ₃ 0-0.1%.

The compressive stress value of the compressive stress layer in the glass substrate for organic EL of the present embodiment is preferably 100 MPa or more, preferably 200 MPa or more, preferably 300 MPa or more, preferably 500 MPa or more, preferably 600 MPa or more, preferably 800 MPa or more, preferably Is 1000 MPa or more, particularly preferably 1200 MPa or more. As the compressive stress increases, the mechanical strength of the tempered glass increases. On the other hand, if an extremely large compressive stress is formed on the surface, microcracks may be generated on the surface, which may lower the mechanical strength of the tempered glass. Moreover, since there exists a possibility that the tensile stress which exists in tempered glass may become extremely high, it is preferable that a compressive stress value shall be 2500 Mpa or less. In order to increase the compressive stress value, the content of Al ₂ O ₃ , TiO ₂ , ZrO ₂ , MgO, ZnO, SnO ₂ may be increased, or the content of SrO, BaO may be decreased. Moreover, what is necessary is just to shorten the time which ion exchange requires, or to lower the temperature of an ion exchange solution.

The stress depth is preferably 5 μm or more, preferably 10 μm or more, preferably 15 μm or more, preferably 20 μm or more, particularly preferably 30 μm or more. The deeper the stress depth, the harder the tempered glass breaks even if the tempered glass is deeply damaged. On the other hand, there is a possibility that the tempered glass is difficult to cut or that the internal tensile stress becomes extremely high and is broken. Therefore, the stress depth is preferably 100 μm or less, preferably 80 μm or less, preferably 60 μm or less, and particularly preferably 50 μm or less. In order to increase the stress depth, the contents of K ₂ O, P ₂ O ₅ , TiO ₂ , and ZrO ₂ may be increased, or the contents of SrO and BaO may be reduced. Moreover, what is necessary is just to lengthen the time which ion exchange requires, or to raise the temperature of an ion exchange solution.

The internal tensile stress is preferably 200 MPa or less, preferably 150 MPa or less, preferably 100 MPa or less, preferably 60 MPa or less, preferably 50 MPa or less, preferably 40 MPa or less, preferably 30 MPa or less, preferably 25 MPa or less, particularly preferably 22 MPa. It is as follows. The smaller this value, the harder it is to break the tempered glass due to internal defects. Moreover, it becomes easy to cut | disconnect tempered glass stably. Furthermore, it becomes possible to reduce the dimensional change at the time of cutting. However, when the internal tensile stress becomes extremely small, the surface compressive stress value and the stress depth are lowered. Therefore, the internal tensile stress is preferably 1 MPa or more, preferably 10 MPa or more, and particularly preferably 15 MPa or more.

The glass substrate for organic EL of this embodiment preferably has an alkali barrier film formed on at least one surface in order to prevent a situation where alkali ions diffuse into the semiconductor material formed in the heat treatment step. . Various materials can be used as the alkali barrier film, but a film of SiO ₂ or SiN _x is preferable in view of film formability and cost. Note that the alkali barrier film can be formed by sputtering, CVD, or the like.

The thickness of the alkali barrier film is preferably 10 to 10000 nm, preferably 10 to 5000 nm, preferably 10 to 3000 nm, particularly preferably 10 to 1000 nm. If the thickness of the alkali barrier film is too small, it will be difficult to prevent the diffusion of alkali ions. On the other hand, when the thickness of the alkali barrier film is too large, the film formation cost is likely to increase.

The plate thickness of the organic EL glass substrate of the present embodiment is preferably 2.0 mm or less, preferably 1.5 mm or less, preferably 1.0 mm or less, preferably 0.8 mm or less, preferably 0.7 mm or less, preferably Is 0.6 mm or less, particularly preferably 0.5 mm or less. The smaller the plate thickness, the lighter the glass substrate. Moreover, the glass substrate for organic EL of this embodiment has an advantage that it is difficult to break even if the plate thickness is reduced. In addition, when a glass substrate is shape | molded with the overflow down draw method, thickness reduction and smoothing of a glass substrate can be achieved without grinding | polishing.

The density of the glass substrate for organic EL of the present embodiment is preferably 2.8 g / cm ³ or less, preferably 2.7 g / cm ³ or less, particularly preferably 2.6 g / cm ³ or less. The lower the density, the lighter the glass. Here, the “density” can be measured by, for example, the well-known Archimedes method. In order to reduce the density, the content of SiO ₂ , P ₂ O ₅ , B ₂ O ₃ is increased or the content of alkali metal oxide, alkaline earth metal oxide, ZnO, ZrO ₂ , TiO ₂ is increased. What is necessary is just to reduce the quantity.

In the glass substrate for organic EL of the present embodiment, the thermal expansion coefficient in a temperature range of 30 to 380 ° C. is preferably 70 × 10 ⁻⁷ to 110 × 10 ⁻⁷ / ° C., preferably 75 × 10 ⁻⁷ to 110 ×. 10 ⁻⁷ / ° C., preferably 80 × 10 ⁻⁷ to 110 × 10 ⁻⁷ / ° C., particularly preferably 85 × 10 ⁻⁷ to 110 × 10 ⁻⁷ / ° C. When the thermal expansion coefficient is within the above range, the thermal expansion coefficient is easily matched with a member such as a metal or an organic adhesive, and peeling of the member such as a metal or an organic adhesive can be prevented. Here, “thermal expansion coefficient” refers to a value obtained by measuring an average thermal expansion coefficient in a temperature range of 30 to 380 ° C. using a dilatometer. In order to increase the coefficient of thermal expansion, the content of alkali metal oxides and alkaline earth metal oxides may be increased. To decrease the coefficient of thermal expansion, alkali metal oxides and alkaline earth metal oxides may be increased. What is necessary is just to reduce content.

The strain point of the organic EL glass substrate of the present embodiment is preferably 500 ° C. or higher, preferably 540 ° C. or higher, preferably 550 ° C. or higher, preferably 560 ° C. or higher, preferably 580 ° C. or higher, preferably 600 ° C. or higher. Preferably it is 620 degreeC or more, Preferably it is 630 degreeC or more, Most preferably, it is 640 degreeC or more. Here, the “strain point” refers to a value measured based on the method of ASTM C336. The higher the strain point, the better the heat resistance, and in the case of bottom emission organic EL, the thermal shrinkage of the glass substrate is reduced even when heat treatment is performed when forming an oxide TFT or the like on a tempered glass substrate. At the same time, the compressive stress layer is difficult to disappear. Also, if the strain point is high, stress relaxation is difficult to occur during the ion exchange treatment, and a high compressive stress value can be obtained. In order to increase the strain point, the content of the alkali metal oxide is reduced or the content of the alkaline earth metal oxide, Al ₂ O ₃ , ZrO ₂ , P ₂ O ₅ is increased. Good.

In the glass substrate for organic EL of the present embodiment, the temperature at 10 ^2.5 dPa · s is preferably 1650 ° C. or less, preferably 1500 ° C. or less, preferably 1450 ° C. or less, preferably 1430 ° C. or less, preferably 1420 ° C. or less, Especially preferably, it is 1400 degrees C or less. Here, “temperature at 10 ^2.5 dPa · s” refers to a value measured by a platinum ball pulling method. The temperature at a high temperature viscosity of 10 ^2.5 dPa · s corresponds to the melting temperature of the glass, and the lower the temperature, the more the glass can be melted. Therefore, the lower the temperature, the smaller the burden on glass manufacturing equipment such as a melting furnace, and the foam quality can be improved. As a result, the glass substrate can be manufactured at low cost. In order to lower the temperature at 10 ^2.5 dPa · s, the content of alkali metal oxide, alkaline earth metal oxide, ZnO, B ₂ O ₃ , TiO ₂ is increased, or SiO ₂ , Al ₂ O _What is necessary is just to reduce the content of ₃ .

The Young's modulus of the glass substrate for organic EL of the present embodiment is preferably 65 GPa or more, preferably 70 GPa or more, preferably 73 GPa or more, and particularly preferably 75 GPa or more. The higher the Young's modulus, the harder the glass substrate bends when used as a display substrate. Here, the “Young's modulus” can be measured by a resonance method, for example.

The liquid phase temperature of the glass substrate for organic EL of the present embodiment is preferably 1250 ° C. or less, preferably 1200 ° C. or less, preferably 1050 ° C. or less, preferably 1030 ° C. or less, preferably 1010 ° C. or less, preferably 1000 ° C. or less. The temperature is preferably 950 ° C. or lower, preferably 900 ° C. or lower, particularly preferably 870 ° C. or lower. To lower the liquidus temperature, the content of Na ₂ O, K ₂ O, B ₂ O ₃ is increased, or the content of Al ₂ O ₃ , Li ₂ O, MgO, ZnO, TiO ₂ , ZrO ₂ is increased. Can be reduced. “Liquid phase temperature” means that glass powder that passes through a standard sieve 30 mesh (a sieve opening of 500 μm) and remains at 50 mesh (a sieve opening of 300 μm) is placed in a platinum boat and is placed in a temperature gradient furnace for 24 hours. It refers to the temperature at which crystals precipitate after being held.

The liquid phase viscosity is preferably 10 ^4.0 dPa · s or more, preferably 10 ^4.3 dPa · s or more, preferably 10 ^4.5 dPa · s or more, preferably 10 ^5.0 dPa · s or more, preferably 10 ^5.4 dPa · s or more, Preferably 10 ^5.8 dPa.s. s or more, preferably 10 ^6.0 dPa · s or more, particularly preferably 10 ^6.2 dPa · s or more. To increase the liquid phase viscosity, increase the content of Na ₂ O, K ₂ O or decrease the content of Al ₂ O ₃ , Li ₂ O, MgO, ZnO, TiO ₂ , ZrO _2. Good. The “liquid phase viscosity” refers to a value obtained by measuring the viscosity at the liquid phase temperature by a platinum ball pulling method.

In addition, the higher the liquidus viscosity and the lower the liquidus temperature, the better the devitrification resistance and the better the moldability. The liquidus temperature is 1200 ° C. or less, if the liquidus viscosity of 10 ^4.0 dPa · s or more, it is possible to form the glass substrate by an overflow down draw method.

The glass substrate for organic EL of this embodiment preferably has an unpolished surface, and the average surface roughness (Ra) of the unpolished surface is preferably 10 mm or less, preferably 5 mm or less, preferably 4 mm or less, Preferably it is 3 mm or less, and particularly preferably 2 mm or less. The average surface roughness (Ra) may be measured by a method based on SEMI D7-97 “Measurement method of surface roughness of FPD glass substrate”. Although the theoretical strength of glass is inherently very high, it often breaks even at stresses much lower than the theoretical strength. This is because a small defect called Griffith flow is generated on the glass surface in a post-molding process such as a polishing process. Therefore, if the glass surface is unpolished, the mechanical strength of the original glass is not impaired and the glass substrate is difficult to break. Further, if the glass surface is unpolished, the polishing step can be omitted, and the manufacturing cost of the glass substrate can be reduced. In the glass substrate for organic EL of the present invention, if the entire effective surface of the glass substrate is unpolished, the glass substrate becomes more difficult to break. Moreover, in order to prevent the situation which breaks from the cut surface of a glass substrate, you may perform a chamfering process, an etching process, etc. to the cut surface of a glass substrate. In order to obtain an unpolished surface, a glass substrate may be formed by an overflow down draw method.

In order to manufacture the glass substrate for organic EL according to the present embodiment, it is preferable that a glass substrate is first prepared and then the glass substrate is subjected to a tempering treatment. The glass substrate may be cut into a predetermined size before the strengthening process, but it is preferable to perform the glass substrate after the strengthening process because the manufacturing cost can be reduced. Note that it is preferable to cut the tempered glass substrate after patterning such as TFT on the tempered glass substrate and sealing with the cap glass. The strengthening process is desirably performed by an ion exchange process. The ion exchange treatment can be performed, for example, by immersing the glass substrate in a potassium nitrate solution at 400 to 550 ° C. for 1 to 8 hours. As the conditions for the ion exchange treatment, optimum conditions may be selected in consideration of the viscosity characteristics of glass, application, plate thickness, internal tensile stress, and the like.

In the glass substrate according to the present embodiment, a glass raw material prepared so as to have a glass composition within the above composition range is charged into a continuous melting furnace, the glass raw material is heated and melted at 1500 to 1600 ° C., and clarified. It can be manufactured by forming molten glass into a plate shape and slowly cooling it.

In order to form a glass substrate, it is preferable to employ an overflow down draw method. If the glass substrate is formed by the overflow down draw method, a glass substrate that is unpolished and has good surface quality can be produced. The reason for this is that, in the case of the overflow down draw method, the surface to be the surface of the glass substrate does not come into contact with the bowl-like refractory, and is molded in a free surface state. This is because it can be molded. Here, the overflow down draw method is to melt the molten glass from both sides of the heat-resistant bowl-like structure and draw the overflowed molten glass downward while joining at the lower end of the bowl-like structure. This is a method for producing a glass substrate.

If high surface quality is not required, a method other than the overflow downdraw method can be adopted. For example, a molding method such as a downdraw method (slot down method, redraw method, etc.), a float method, a rollout method, or a press method can be employed.

Hereinafter, examples of the present invention will be described. The present invention is not limited to the following examples. The following examples are merely illustrative.

Tables 1 to 8 show examples of the present invention (sample Nos. 1 to 57). In addition, the display of “not yet” in the table means not measured.

The samples shown in Tables 1 to 8 were prepared as follows. First, the glass raw material was prepared so that it might become the glass composition in a table | surface, and it melted at 1580 degreeC for 8 hours using the platinum pot. Thereafter, the molten glass was poured onto a carbon plate and formed into a plate shape. Various characteristics were evaluated about the obtained glass substrate.

The density was measured by the well-known Archimedes method.

The strain point Ps and the annealing point Ta were measured based on the method of ASTM C336.

The softening point Ts was measured based on the method of ASTM C338.

The temperature at a high temperature viscosity of 10 ^4.0 dPa · s, 10 ^3.0 dPa · s, 10 ^2.5 dPa · s was measured by a platinum ball pulling method.

The Young's modulus was measured by a bending resonance method.

As the thermal expansion coefficient α, an average thermal expansion coefficient in a temperature range of 30 to 380 ° C. was measured using a dilatometer.

The liquid phase temperature TL is obtained by crushing glass, passing through a standard sieve 30 mesh (a sieve opening of 500 μm), and putting the glass powder remaining in 50 mesh (a sieve opening of 300 μm) into a platinum boat and placing it in a temperature gradient furnace for 24 hours. The temperature at which the crystals were deposited was measured.

Liquid phase viscosity logηTL is the viscosity of the glass at the liquidus temperature.

As a result, the obtained glass substrate had a density of 2.59 g / cm ³ or less, a thermal expansion coefficient of 83 × 10 ⁻⁷ to 100 × 10 ⁻⁷ / ° C., and was suitable as a material for tempered glass. In addition, since the liquid phase viscosity is 10 ^4.2 dPa · s or more, it can be molded by the overflow downdraw method, and the temperature at 10 ^2.5 dPa · s is as low as 1614 ° C. It is thought that it can be produced.

Subsequently, sample No. Both surfaces 1 to 46 were subjected to optical polishing and then subjected to ion exchange treatment. Sample No. For samples 1 to 8, 13 to 15, 24 and 25, 47 to 57, each sample was placed in KNO ₃ molten salt at 430 ° C. for 4 hours. For Nos. 9-12, 16-23, and 26, each sample was placed in KNO ₃ molten salt at 460 ° C. for 4 hours, 27 to 46 were carried out by immersing each sample in KNO ₃ molten salt at 440 ° C. for 6 hours. After the ion exchange treatment, each sample is thoroughly washed, and the surface compressive stress value and stress depth are calculated from the number of interference fringes observed using a surface stress meter (FSM-6000 manufactured by Toshiba Corporation) and the interval between them. did. In the calculation, the refractive index of the sample was 1.53, and the optical elastic constant was 28 [(nm / cm) / MPa]. In addition, although glass composition differs microscopically in the surface layer of glass, unstrengthened glass and tempered glass do not differ substantially in glass composition as the whole glass. Therefore, characteristic values such as density and viscosity are not substantially different between untempered glass and tempered glass.

As a result, sample No. A compressive stress of 277 MPa or more was generated on the surfaces 1 to 57, and the depth thereof was 7 μm or more. When the plate thickness was 1 mm, the internal tensile stress was 43 MPa or less.

Sample No. Using 15 glass substrates, test pieces having different internal tensile stresses were prepared by changing the plate thickness and ion exchange treatment conditions. Next, the state of breakage due to internal tensile stress was evaluated for each test piece. The evaluation method is as follows.

A glass substrate having a thickness of 0.5 mm and a thickness of 0.7 mm was prepared, and each glass substrate was cut into a size of 35 mm × 35 mm. Each glass substrate thus obtained was subjected to ion exchange treatment under conditions of 460 ° C. for 6 hours, 460 ° C. for 8 hours, and 490 ° C. for 6 hours, and then the compressive stress value and the stress depth were measured. The results are shown in Table 9. The compressive stress value and the stress depth were measured by the same method as described above, and the internal tensile stress was calculated from these values.

Subsequently, it was investigated whether the glass substrate was damaged when the scratches formed on the surface of the glass substrate reached the internal tensile stress region. Use a scribe machine with wheel tip material made of diamond, set air pressure to 0.3 MPa, wheel tip blade angle to 125 °, wheel tip polishing grade to D521, and hit the wheel tip against the surface of the glass substrate. The glass substrate was destroyed.

Table 10 shows the number of pieces after breaking the glass substrate. For reference, the number of fragments of a glass substrate (unreinforced glass substrate) having no internal tensile stress without performing ion exchange treatment is also shown. As is clear from Table 10, it can be understood that when the internal tensile stress is 50 to 94 MPa, the number of pieces is the same as that of the glass substrate having the internal stress of 0.

Example No. by the overflow down draw method. Forty glasses were molded to a thickness of 0.7 mm. At that time, the temperature range of the annealer zone arranged at the bottom of the compact was adjusted, and the length and temperature of the annealer were adjusted so that the cooling rate in the temperature range from 730 ° C to 580 ° C was 50 ° C / min. .

The obtained glass substrate was subjected to ion exchange treatment in a KNO ₃ molten salt containing 40 ppm of Li ₂ O under conditions of 440 ° C. and 6 hours. As a result, the compressive stress value of the compressive stress layer was 600 MPa, the stress depth was 34 μm, and the internal tensile stress was 32 MPa.

1 and 2 show structural examples when an organic EL device is produced using the organic EL glass substrate of the present invention.

The organic EL device shown in FIG. 1 is arranged in the order of an unstrengthened glass substrate 1, a TFT 2, an organic EL element 3, a transparent electrode 4, and a tempered glass substrate 5, and the unstrengthened glass substrate 1 and the tempered glass substrate 5 are sealed. It has a structure sealed with a stop material 6.

The organic EL device shown in FIG. 2 is arranged in the order of a tempered glass substrate 7, a TFT 8, a transparent electrode 9, an organic EL element 10, a metal electrode 11, and a sealing layer 12. Has a structure sealed with a sealing material 13. Although not shown in the drawing, it is preferable to form an alkali barrier film on the surface of the tempered glass substrate 7.

In the above examples, for the convenience of explanation of the present invention, glass was melted and cast by casting, followed by optical polishing before ion exchange treatment. When producing on an industrial scale, it is desirable to produce a glass substrate by an overflow down draw method or the like, and to perform the ion exchange treatment with both surfaces of the glass substrate being unpolished.

1 Unstrengthened glass substrate 2, 8 TFT
3, 8 Organic EL element 4, 9 Transparent electrode 5, 7 Tempered glass substrate 6, 13 Sealing material 11 Metal electrode 12 Sealing layer

Claims (9)

An organic EL glass substrate having a compressive stress layer on the surface. _2. The organic EL device according to claim 1, wherein the glass composition contains SiO ₂ 40-80%, Al ₂ O ₃ 1-25%, and Na ₂ O 0.5-20% by mass. Glass substrate. The glass substrate for organic EL according to claim 2, wherein the glass substrate is chemically strengthened. The organic EL glass substrate according to claim 2 or 3, wherein the compressive stress of the compressive stress layer is 100 MPa or more, the stress thickness is 10 µm or more, and the internal tensile stress is 200 MPa or less. The glass substrate for organic EL according to claim 2 or 3, wherein an alkali barrier film is formed on at least one surface. 6. The glass substrate for organic EL according to claim 5, wherein the alkali barrier film has a thickness of 10 to 1000 nm. A glass raw material prepared to have a glass composition containing 40% to 80% SiO ₂ , 1 to 25% Al ₂ O _{3, and} 0.5 to 20% Na ₂ O by mass% is melted and formed into a plate shape Then, an ion exchange treatment is performed to form a compressive stress layer on the glass surface. The method for producing a glass substrate for organic EL according to claim 7, wherein the glass substrate is formed into a plate shape by a downdraw method. The method for producing a glass substrate for organic EL according to claim 7, wherein the glass substrate is formed into a plate shape by an overflow downdraw method.

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