KR102427006B1 - Bismuth-based glass, bismuth-based glass manufacturing method and sealing material - Google Patents

Abstract

The bismuth-based glass of the present invention has a glass composition, and is Bi ₂ O ₃ 25 to 45%, B ₂ O ₃ 20 to 35%, Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO+CuO+MnO+Fe ₂ O ₃ +TiO ₂ in mole % in terms of the following oxides. +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO 90 to 100% (but not including 90%), molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO) is characterized in that 2.0 to 3.5.

Description

Bismuth-based glass, bismuth-based glass manufacturing method and sealing material

The present invention relates to bismuth-based glass, a method for manufacturing bismuth-based glass, and a sealing material, and more particularly, to a manufacturing method and sealing material of bismuth-based glass and bismuth-based glass suitable for sealing treatment by laser light (hereinafter, laser sealing) will be.

DESCRIPTION OF RELATED ART In recent years, organic electroluminescent display attracts attention as a flat display panel. Conventionally, an organic resin-based adhesive having low-temperature curability has been used as an adhesive material for an organic EL display. However, since the organic resin adhesive cannot completely block the penetration of gas or moisture, an active element or organic light emitting layer having low water resistance tends to deteriorate, resulting in a problem that the display characteristics of the organic EL display deteriorate over time.

On the other hand, since the sealing material including the glass powder is less permeable to gas or moisture than the organic resin-based adhesive, airtightness inside the organic EL display can be secured.

However, since the glass powder has a higher softening temperature than the organic resin adhesive, there is a fear that the active element or the organic light emitting layer may be deteriorated at the time of sealing. From these circumstances, laser sealing is attracting attention. According to laser sealing, it is possible to locally heat only the portion to be sealed, so that an object to be sealed such as an alkali-free glass substrate can be sealed without deteriorating the active element or the organic light emitting layer.

Moreover, in recent years, maintaining the characteristics of an airtight package and aiming at the improvement of life is examined. For example, in a hermetic package in which an LED element is mounted, aluminum nitride and a low-temperature fired substrate (LTCC) having a thermal via are used as the substrate from the viewpoint of thermal conductivity. Even in this case, it is preferable to laser-seal the substrate and the lid (lead). do. In particular, in the hermetic package in which the LED element emitting light in the ultraviolet wavelength region is mounted, it becomes easy to maintain the light emitting characteristic in the ultraviolet wavelength region by laser sealing. Further, thermal deterioration of the LED element can be prevented by laser sealing.

In addition, even in an airtight package in which a micro electric mechanical system (MEMS) device is mounted, laser sealing is suitable to prevent deterioration of characteristics of the MEMS device.

Specification of US Patent No. 6416375 Japanese Patent Laid-Open No. 2006-315902

Sealing materials used for laser sealing generally include glass powder, refractory filler powder, and a laser absorber. The glass powder is a component for ensuring sealing strength by softening and flowing during laser sealing and reacting with the object to be sealed. The refractory filler powder acts as an aggregate and is a material for lowering the coefficient of thermal expansion, and does not soften and flow during laser sealing. The laser absorbing material is a material for absorbing laser light and converting it into thermal energy during laser sealing, and does not soften and flow during laser sealing.

As a glass powder, lead-boric-acid type glass was used conventionally, but lead-free glass is used from an environmental viewpoint in recent years. In particular, since bismuth-based glass has a low melting point and is excellent in softening fluidity, it is promising as lead-free glass. However, the bismuth-based glass tends to have insufficient laser absorbing power because Bi ₂ O ₃ as the main component does not have most of the laser absorbing power. Therefore, the content of the laser absorbing material must be increased in order to supplement the laser absorbing power of the bismuth-based glass. However, when the content of the laser absorber increases, the laser absorber penetrates into the bismuth-based glass during laser sealing, thereby devitrifying the bismuth-based glass, making it impossible to secure the desired softening fluidity. In addition, if the refractory filler powder is lowered to ensure softening fluidity, the thermal expansion coefficient of the sealing material is unreasonably increased, so that cracks are generated in the object to be sealed or the sealing material layer during laser sealing, which tends to cause airtight failure.

Therefore, the present invention has been made in view of the above circumstances, and its technical object is to create a bismuth-based glass capable of achieving both softening fluidity and laser absorption capability at a high level, and a sealing material using the same.

MEANS TO SOLVE THE PROBLEM As a result of earnest examination, this inventor discovers that the said technical subject can be solved by strictly regulating the ratio of the non-colored component in bismuth-type glass, and a coloring component, and proposes as this invention. That is, the bismuth-based glass of the present invention has a glass composition in terms of mol% in terms of the following oxides: Bi ₂ O ₃ 25 to 45%, B ₂ O ₃ 20 to 35%, Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO+CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO 90 to 100% (but not including 90%), molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO) is characterized in that 2.0 to 3.5. Here, "Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO+CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO" is Bi ₂ O ₃ , B ₂ O ₃ , BaO, ZnO, CuO, MnO, Indicates the content of Fe ₂ O ₃ , TiO ₂ , V ₂ O ₅ , Cr ₂ O ₃ , Co ₃ O ₄ and NiO. "( _{Bi2O3 + B2O3 +} BaO+ZnO)/(CuO+MnO ₊ Fe2O3+TiO2 _{+ V2O5 + Cr2O3 + Co3O4 +} NiO)" is _{Bi2O3 , B2O3} , _{BaO and} ZnO It refers to a value obtained by dividing the content by the content of CuO, MnO, Fe ₂ O ₃ , TiO ₂ , V ₂ O ₅ , Cr ₂ O ₃ , Co ₃ O ₄ and NiO.

In the bismuth-based glass of the present invention, the ratio of the non-colored component to the colored component is strictly regulated. Specifically, the bismuth-based glass of the present invention has a molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO) of 2.0 to 3.5. are regulating If the molar ratio ( _{Bi2O3 + B2O3 +} BaO+ZnO)/(CuO+MnO ₊ Fe2O3+TiO2 _{+ V2O5 + Cr2O3 + Co3O4} +NiO) is too small, _it becomes thermally unstable _and the glass devitrifies during laser sealing. it becomes easier to become _On the other hand, when the molar ratio ( _{Bi2O3 + B2O3 + BaO} +ZnO)/(CuO+MnO ₊ Fe2O3+TiO2 _{+ V2O5 + Cr2O3 + Co3O4} +NiO) is too large, laser absorption ability will fall easily. As a result, if the laser absorbing material is excessively added to the sealing material or the laser power is not increased, the laser sealing becomes difficult. In addition, the coefficient of thermal expansion is unreasonably high, and cracks are generated in the object to be sealed or the sealing material layer during laser sealing, which tends to cause airtight failure.

Second, in the bismuth-based glass of the present invention, the content of ZnO is preferably 1 to 20 mol%.

Third, in the bismuth-based glass of the present invention, the content of MnO is preferably 3 to 25 mol%.

Fourth, it is preferable that the bismuth-based glass of the present invention contains substantially no PbO. Here, "it does not contain PbO substantially" refers to the case where content of PbO in a glass composition is less than 0.1 mass %.

Fifth, the method for producing bismuth-based glass of the present invention is the method for producing bismuth-based glass, wherein a glass batch containing any one of a nitrate raw material, a sulfate raw material, a dioxide raw material, and a peroxide raw material is melted and molded to form the bismuth-based glass. It is preferable to manufacture

Sixth, in the method for producing a bismuth-based glass of the present invention, it is preferable that the raw material for the above-mentioned oxide material is a raw material for manganese dioxide.

Seventh, in the method for producing a bismuth-based glass of the present invention, it is preferable that the peroxide raw material is a permanganate raw material.

Eighth, the sealing material of the present invention includes a glass powder made of bismuth-based glass and a refractory filler powder, wherein the content of the glass powder is 50 to 95% by volume and the content of the refractory filler powder is 1 to 40% by volume %, and the bismuth-based glass is preferably the bismuth-based glass.

Ninth, in the sealing material of the present invention, the refractory filler powder is selected from cordierite, willemide, alumina, zirconium phosphate-based compounds, zircon, zirconia, tin oxide, quartz glass, β-eucryptite, and spodumene. It is preferable that it is 1 type or 2 or more types used.

Tenth, it is preferable that the content of the laser absorbing material in the sealing material of the present invention is 5% by volume or less.

Eleventh, the sealing material of the present invention is preferably used for laser sealing. In this way, thermal deterioration of the element during sealing can be prevented. In addition, the light source of the laser beam used for laser sealing is although it does not specifically limit, For example, a semiconductor laser, a YAG laser, _a CO2 laser, an excimer laser, an infrared laser, etc. are suitable from the point of easy handling. In addition, the emission center wavelength of the laser light is preferably 500 to 1600 nm, particularly preferably 750 to 1300 nm, in order to accurately absorb the laser light by the sealing material.

The bismuth-based glass of the present invention has a glass composition as described above, in terms of mol% in terms of the following oxides, Bi ₂ O ₃ 25 to 45%, B ₂ O ₃ 20 to 35%, Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO+CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO 90-100% (but not including 90%), molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO2 _{+ V2O5} + _{Cr2O3 + Co3O4} + _NiO ) is _2.0-3.5 . As described above, the reason for limiting the glass composition range of the bismuth-based glass is shown below. Incidentally, in the description of the glass composition, % indicates mole %.

Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO+CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO content is greater than 90%, preferably 93% or more, 95% or more, 97% or more, In particular, more than 98%. If the content of Bi ₂ O ₃ + _{B 2} O ₃ +BaO+ZnO+CuO+MnO ₊ Fe2O3+TiO2 _{+ V2O5} + _{Cr2O3 + Co3O4} +NiO is too small, _it becomes difficult to _achieve both softening fluidity and laser absorption ability. As a result, if the laser absorbing material is excessively added to the sealing material or the laser power is not increased, laser sealing becomes difficult.

Content of CuO+MnO ₊ Fe2O3+TiO2 _{+ V2O5 + Cr2O3 + Co3O4} +NiO becomes like this _. Preferably it is ₂₂ to 33 %, More preferably, it is 25 to 30 %. When there is too little content of CuO+MnO ₊ Fe2O3+TiO2 _{+ V2O5 + Cr2O3 + Co3O4} + _NiO , _the laser absorption ability will fall easily. As a result, if the laser absorbing material is excessively added to the sealing material or the laser power is not increased, the laser sealing becomes difficult. _On the other hand, when there is too much content of CuO+MnO ₊ Fe2O3+TiO2 _{+ V2O5 + Cr2O3 + Co3O4} +NiO, _it becomes thermally unstable, and it becomes easy to devitrify glass at the time of laser sealing.

The molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO) is 2.0 to 3.5, preferably 2.1 to 3.2, more preferably is 2.2 to 3.1, particularly preferably 2.4 to 3.0. If the molar ratio ( _{Bi2O3 + B2O3 +} BaO+ZnO)/(CuO+MnO ₊ Fe2O3+TiO2 _{+ V2O5 + Cr2O3 + Co3O4} +NiO) is too small, _it becomes thermally unstable _and the glass devitrifies during laser sealing. it becomes easier to become _On the other hand, when the molar ratio ( _{Bi2O3 + B2O3 + BaO} +ZnO)/(CuO+MnO ₊ Fe2O3+TiO2 _{+ V2O5 + Cr2O3 + Co3O4} +NiO) is too large, laser absorption ability will fall easily. As a result, if the laser absorbing material is excessively added to the sealing material or the laser power is not increased, the laser sealing becomes difficult. Further, the coefficient of thermal expansion is unreasonably high, so that cracks are generated in the object to be sealed or the sealing material layer during laser sealing, which tends to cause airtight failure.

Bi ₂ O ₃ is a major component of the bismuth-based glass, and is a component that enhances softening fluidity. The content of Bi ₂ O ₃ is 25 to 45%, preferably 30 to 42%, more preferably 35 to 40%. When there is too little content _of Bi2O3, a softening point becomes _high too much, and even if it irradiates a laser beam, it becomes difficult for glass to soften and flow. On the other hand, when the content of Bi ₂ O ₃ is too large, the coefficient of thermal expansion is unreasonably high, and cracks are generated in the object to be sealed or the sealing material layer during laser sealing, which tends to cause airtight failure. Moreover, it becomes thermally unstable, and it becomes easy to devitrify glass at the time of laser sealing.

B ₂ O ₃ is a component that forms a glass network. The content of B ₂ O ₃ is 20 to 35%, preferably 22 to 32%, more preferably 24 to 30%. When there is too little content _{of B2O3} , glass will become thermally unstable, and it will become easy to devitrify glass at the time of laser sealing. On the other hand, when there is too much content _{of B2O3} , a softening point will become high too much, and even if it irradiates a laser beam, it becomes difficult for glass to soften and flow.

BaO is a component that lowers the softening point and also a component that improves thermal stability. However, when there is too much content of BaO, it will become difficult to reduce a thermal expansion coefficient. As a result, cracks and the like are likely to occur in the sealing material layer. Accordingly, the content of BaO is preferably 0 to 15%, 0 to 8%, 0 to 5%, and particularly less than 0.1 to 2%.

ZnO is a component that lowers the coefficient of thermal expansion. The content of ZnO is preferably 0 to 25%, more preferably 1 to 20%, still more preferably 5 to 15%. When there is too little content of ZnO, the thermal expansion coefficient becomes high easily. On the other hand, when the content of ZnO is too large, when the content of Bi ₂ O ₃ is 35% or more, the glass becomes thermally unstable, and the glass tends to devitrify during laser sealing.

CuO and MnO are components that significantly increase laser absorption. The content of CuO and MnO is preferably 15 to 35%, more preferably 20 to 40%, still more preferably 25 to 30%. When the content of CuO and MnO is too small, the laser absorption ability tends to decrease. On the other hand, when the content of CuO and MnO is too large, the softening point becomes too high, and it becomes difficult for the glass to soften and flow even when irradiated with laser light. In addition, the glass becomes thermally unstable, so that the glass tends to devitrify during laser sealing. Moreover, content of CuO becomes like this. Preferably it is 5 to 30 %, More preferably, it is 8 to 30 %, More preferably, it is 13 to 25 %. The content of MnO is preferably 0 to 20%, more preferably 3 to 25%, still more preferably 5 to 15%.

A raw material for introducing MnO, such as MnO ₂ , has an oxidizing action upon melting. And, in bismuth-based glass, when CuO and MnO are used together and the molar ratio CuO/MnO is regulated to 0.5 to 6.2, Cu ₂ O present in the glass at the time of melting is oxidized by the introduction raw material of MnO, and oxidation number of 2 or more is oxidized. Copper increases, whereby the laser absorption capacity in the near-infrared wavelength region can be significantly improved. Molar ratio CuO/MnO becomes like this. Preferably it is 0.5-6.2, More preferably, it is 0.7-6.0, More preferably, it is 1.0-3.5. When the molar ratio CuO/MnO is too small, the glass becomes thermally unstable and the glass tends to devitrify at the time of laser sealing. On the other hand, when the molar ratio CuO/MnO is too large, Cu ₂ O is not sufficiently oxidized at the time of melting, making it difficult to obtain a desired laser absorbing power.

Fe ₂ O ₃ is a component that enhances laser absorbing power, and when the content of Bi ₂ O ₃ is 35% or more, it is a component that suppresses devitrification at the time of laser sealing. The content of Fe ₂ O ₃ is preferably 0 to 5%, 0.1 to 3%, and particularly 0.2 to 2%. When there is too much content _of Fe2O3, _the component balance in a glass composition will be impaired and glass will become easy to devitrify conversely.

TiO ₂ , V ₂ O ₅ , Cr ₂ O ₃ , Co ₂ O ₃ and NiO are components that increase laser absorption. The content of each component is preferably 0 to 7%, 0.1 to 4%, particularly less than 0.5 to 2%. When there is too much content of each component, it will become easy to devitrify glass at the time of laser sealing.

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

Al ₂ O ₃ is a component that improves water resistance. The content is preferably 0 to 5%, 0 to 3%, and particularly preferably 0.1 to 2%. When there is too much content _of Al2O3, a softening point will become _high too much, and even if it irradiates a laser beam, it becomes difficult for glass to soften and flow.

MgO, CaO and SrO are components that increase thermal stability. However, when there is too much content of MgO, CaO, and SrO, it will become difficult to reduce a thermal expansion coefficient, ensuring softening fluidity|liquidity. Accordingly, the content and individual content of MgO, CaO and SrO is preferably 0-7%, 0-5%, 0-3%, less than 0-2%, 0-1%, in particular less than 0-1%.

SiO2 is _a component which improves water resistance. The content is preferably 0 to 8%, 0 to 5%, and particularly preferably less than 0 to 1%. When there is too much content _of SiO2, a softening point becomes high too much, and even if it irradiates a laser beam, it becomes difficult for glass to soften and flow.

Li ₂ O, Na ₂ O, K ₂ O, and Cs ₂ O are components that lower the softening point, but have an action of promoting devitrification at the time of melting. Accordingly, the content of these components is preferably 2% or less, particularly less than 1% in terms of content.

_{Although P2O5} is a component which suppresses devitrification at the time of melting, when there is too much the addition amount, it will become easy to separate glass at the time of melting. Therefore, the content of P ₂ O ₅ is preferably 0 to 5%, particularly preferably less than 0 to 1%.

La ₂ O ₃ , Y ₂ O ₃ , and Gd ₂ O ₃ are components that suppress the phase separation at the time of melting, but when the contents of La ₂ O ₃ , Y ₂ O ₃ and Gd ₂ O ₃ are too large, the softening point becomes too high and laser beam Even if irradiated, the glass becomes difficult to soften. Therefore, the content of La ₂ O ₃ , Y ₂ O ₃ , and Gd ₂ O ₃ is preferably 0 to 5%, respectively, and particularly preferably less than 0 to 1%.

MoO ₃ and CeO ₂ are components that increase laser absorption. The content of each component is preferably 0 to 7%, 0 to 4%, particularly less than 0 to 1%. When the content of each component is too large, the glass tends to be devitrified at the time of laser sealing.

It is preferable not to contain PbO substantially from an environmental viewpoint.

The sealing material of the present invention is a sealing material comprising a glass powder made of bismuth-based glass and a refractory filler powder, wherein the content of the glass powder is 50 to 95% by volume and the content of the refractory filler powder is 1 to 40% by volume, and The bismuth-based glass is preferably the bismuth-based glass.

In the sealing material of the present invention, the content of the glass powder is preferably 50 to 95% by volume, 60 to 80% by volume, and particularly preferably 65 to 75% by volume. When the content of the glass powder is small, the softening fluidity of the sealing material tends to decrease. On the other hand, when the content of the glass powder is large, the content of the refractory filler powder is relatively small, and there is a fear that the coefficient of thermal expansion of the sealing material becomes unduly high.

The maximum particle diameter (D _max ) of the glass powder is preferably 10 µm or less, particularly 5 µm or less. When the maximum particle diameter (D _max ) of the glass powder is too large, the time required for laser sealing becomes long, and it becomes difficult to equalize the gap between objects to be sealed, and the precision of laser sealing tends to decrease. Here, "maximum particle diameter (D _max )" refers to a value measured by a laser diffraction apparatus, and the cumulative amount is accumulated from the smaller particle size in the volume-based cumulative particle size distribution curve when measured by laser diffraction method. It represents a particle diameter of 99%.

The softening point of the glass powder is preferably 480°C or less, 450°C or less, and particularly preferably 350 to 430°C. If the softening point of the glass powder is too high, the sealing strength cannot be increased unless the output of the laser beam is increased because the glass becomes difficult to soften at the time of laser sealing. Here, the "softening point" refers to the temperature of the 4th inflection point when measured by macro-type differential thermal analysis.

Glass powder prepares, for example, a glass batch combining various raw materials, puts this into platinum melting, melts it at 900 to 1200°C for 1 to 3 hours, then pours the molten glass between water-cooled twin rollers to shape it into a film and grind|pulverizes the obtained glass film with a ball mill, and is produced by performing classification, such as air classification.

It is preferable to use 1 type or 2 or more types of a nitrate raw material, a sulfate raw material, a dioxide raw material, and a peroxide raw material for a part of the raw material used for manufacture of a bismuth-type glass. In particular, it is preferable to use a nitrate raw material as a raw material for introducing Bi ₂ O ₃ , it is preferable to use a manganese dioxide raw material as a dioxide raw material, and it is preferable to use a permanganate raw material as a peroxide raw material. Among the coloring components, there is a component (especially CuO) whose laser absorbing power increases when the oxidation number is high. And when such a raw material is used, the oxidation number of the coloring component in a molten glass can be made high.

In the sealing material of the present invention, the content of the refractory filler powder is preferably 1 to 40% by volume, 10 to 45% by volume, 20 to 40% by volume, particularly 22 to 35% by volume. When the content of the refractory filler powder is small, there is a risk that the thermal expansion coefficient of the sealing material becomes unduly high. On the other hand, when the content of the refractory filler powder is large, the content of the glass powder is relatively small, so that the softening fluidity of the sealing material tends to decrease.

Various materials can be used as the refractory filler powder, but among them, one selected from cordierite, willemite, alumina, zirconium phosphate-based compound, zircon, zirconia, tin oxide, quartz glass, β-eucryptite, and spodumene Or 2 or more types are preferable. These refractory filler powders have a high mechanical strength in addition to a low coefficient of thermal expansion, and both have good compatibility with the bismuth-based glass of the present invention. In addition, β-eucryptite is particularly preferable because of its high effect of lowering the thermal expansion coefficient of the sealing material.

The maximum particle diameter (D _max ) of the refractory filler powder is preferably 15 µm or less, less than 10 µm, less than 5 µm, in particular less than 0.5 to 3 µm. When the maximum particle diameter (D _max ) of the refractory filler powder is too large, it becomes difficult to equalize the gap between the objects to be sealed, and it becomes difficult to narrow the gap between the objects to be sealed, and it becomes difficult to reduce the thickness of the organic EL display or the hermetic package. . Further, when the gap between the object to be sealed is large and the difference in the coefficient of thermal expansion between the object to be sealed and the sealing material layer is large, cracks or the like are likely to occur in the object to be sealed or the sealing material layer.

In the sealing material of the present invention, the content of the laser absorber is preferably 0 to 5% by volume, 0 to 3% by volume, 0 to 1% by volume, particularly 0 to 0.1% by volume. When the content of the laser absorbing material is too large, the laser absorbing material is dissolved into the glass during laser sealing, whereby the glass is devitrified and the softening fluidity of the sealing material is easily lowered. In addition, the content of the refractory filler powder is relatively small, and there is a fear that the coefficient of thermal expansion is unreasonably increased.

In the sealing material of the present invention, the light absorptivity in monochromatic light having a wavelength of 808 nm is preferably 75% or more, more preferably 80% or more. If the light absorptivity is low, the sealing strength cannot be increased unless the sealing material layer cannot adequately absorb the light during laser sealing and the output of the laser light is not increased. Moreover, when the output of a laser beam is raised, there exists a possibility that an element may thermally deteriorate at the time of laser sealing. Here, the "light absorptivity for monochromatic light with a wavelength of 808 nm" is measured by measuring the reflectance and transmittance of monochromatic light with λ = 808 nm respectively with a spectrophotometer for the sealing material layer baked to a thickness of 5 µm, and the sum of these values is 100 It corresponds to the value subtracted from %.

In the sealing material of the present invention, the coefficient of thermal expansion is preferably 75×10 ^-7 /°C or less, particularly 50×10 ^-7 /°C or more, and further 71×10 ^-7 /°C or less. In this way, when the object to be sealed has low expansion, since the stress remaining in the object to be sealed or the sealing material layer is reduced, cracks are less likely to occur in the object to be sealed or the sealing material layer. Here, the "coefficient of thermal expansion" refers to a value measured by a press-bar type coefficient of thermal expansion measurement (TMA) device, and the measurement temperature range is set to 30 to 300°C.

In the sealing material of the present invention, the softening point is preferably 510°C or less, 480°C or less, particularly 350 to 450°C. If the softening point of the sealing material is too high, the sealing material layer becomes difficult to soften and flow during laser sealing, so that the sealing strength cannot be increased unless the output of the laser light is increased.

The sealing material of the present invention may be provided for use in a powder state, but it is easy to handle if it is uniformly kneaded with a vehicle and processed into a sealing material paste. The vehicle is mainly composed of a solvent and a resin. The resin is added for the purpose of adjusting the viscosity of the sealing material paste. In addition, if necessary, a surfactant, a thickener, etc. may be added. The sealing material paste is applied on an object to be sealed by using an applicator such as a dispenser or a screen printing machine, and then provided to a binder removal process.

As the resin, acrylic acid ester (acrylic resin), ethyl cellulose, polyethylene glycol derivative, nitrocellulose, polymethyl styrene, polyethylene carbonate, methacrylic acid ester and the like can be used. In particular, acrylic acid ester and nitrocellulose are preferable because of their good thermal decomposition properties.

As the solvent, N,N'-dimethylformamide (DMF), α-terpineol, higher alcohol, γ-butyllactone (γ-BL), tetralin, butylcarbitol acetate, ethyl acetate, isoamyl acetate, Diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, benzyl alcohol, toluene, 3-methoxy-3-methylbutanol, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, Dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, propylene carbonate, dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone and the like can be used.

Example

The present invention will be described in detail based on Examples. In addition, the following examples are mere examples. The present invention is not limited in any way to the following examples.

Tables 1 and 2 show the Examples (Sample Nos. 1 to 6) and Comparative Examples (Sample Nos. 7 to 10) of the present invention.

As follows, the glass powder described in the table|surface was produced. First, the glass batch which combined various raw materials so that it might become the glass composition in a table|surface was prepared, this was put into a platinum crucible, and it melt|melted at 1000 degreeC for 1 hour. At the time of melting, the molten glass was homogenized by stirring using a platinum rod. In addition, about sample _No.3 - ₅ , 10% of content of Bi2O3 was introduce|transduced by the nitrate raw material. Next, a part of the obtained molten glass was flowed out between water-cooled twin rollers, and it shape|molded into film shape, the remaining molten glass was made to flow out into a carbon mold, and it shape|molded in rod shape. Finally, the obtained glass film was pulverized with a ball mill and then classified with an air classifier such that the average particle diameter (D ₅₀ ) was 1.0 μm and the maximum particle diameter (D _max ) was 4.0 μm. In addition, about rod-shaped glass, after putting in the electric furnace maintained at the temperature about 20 degreeC higher than the slow cooling point, it was slow-cooled to room temperature at the temperature-fall rate of 3 minutes/min.

As the refractory filler powder, β-eucryptite was used. The refractory filler powder is adjusted to an average particle diameter (D ₅₀ ) of 1.0 µm and a maximum particle diameter (D _max ) of 3.0 µm by air classification.

Glass powder and refractory filler powder were mixed at the mixing ratio shown in Table, and Sample No. 1-10 were produced. Sample Nos. 1 to 10 were evaluated for coefficient of thermal expansion, light absorption, softening fluidity, sealing strength, and airtightness. In addition, "component A" in the table indicates the content of Bi ₂ O ₃ , B ₂ O ₃ , BaO and ZnO, and "component B" is CuO, MnO, Fe ₂ O ₃ , TiO ₂ , V ₂ O ₅ , Cr The contents of ₂ O ₃ , Co ₃ O ₄ and NiO are shown, and “N/A” indicates the inability to evaluate.

The coefficient of thermal expansion is a value measured in a temperature range of 30 to 300°C by a TMA device. In addition, as a measurement sample for TMA, after each sample was densely sintered, what was processed into a predetermined shape was used.

The light absorptance was measured as follows. First, each sample and vehicle (tripropylene glycol monobutyl ether containing ethyl cellulose resin) are uniformly kneaded by a three-stage roll mill to form a paste, and then an alkali-free glass substrate (OA- manufactured by NIPPON ELECTRIC GLASS CO., LTD.) 10, 40 mm x 40 mm x 0.5 mm thick), it apply|coated on the square of 30 mm x 30 mm, and it dried in the drying oven at 120 degreeC for 10 minutes. Then, the temperature was raised at 10°C/min from room temperature, and after baking at 510°C for 10 minutes, the temperature was lowered to room temperature at 10°C/min, and fixed on a glass substrate. Then, the reflectance and transmittance of monochromatic light having a wavelength of λ = 808 nm were respectively measured with a spectrophotometer for the obtained fired film having a film thickness of 5 µm, and the value obtained by subtracting the total value from 100% was taken as the light absorptivity.

For softening fluidity, for each sample, powder of a mass equivalent to 0.6 cm 3 min is dry-pressed into a button shape with an outer diameter of 20 mm by a mold, and this is loaded on an alumina substrate of 25 mm × 25 mm × 0.6 mm thickness, and in the air. After raising the temperature at a rate of 10°C/min, the temperature was lowered to room temperature at 10°C/min after holding at 510°C for 10 minutes, and measuring the diameter of the obtained button was evaluated. Specifically, the case where the flow diameter was 16.0 mm or more was evaluated as "○", and the case where it was less than 16.0 mm was evaluated as "x".

The sealing strength was evaluated as follows. First, each sample and vehicle (tripropylene glycol monobutyl ether containing ethyl cellulose resin) are uniformly kneaded by a three-stage roll mill to form a paste, and then an alkali-free glass substrate (OA-10 manufactured by NIPPON ELECTRIC GLASS CO., LTD.) , □ 40㎜×0.5㎜ thick, coefficient of thermal expansion 38×10 ^-7 /℃), along the edge of the alkali-free glass substrate, applied in a frame shape (5㎛ thickness, 0.6㎜ width) and dried in a drying oven at 120℃ , and dried for 10 minutes. Then, the temperature is raised from room temperature to 10°C/min, calcined at 510°C for 10 minutes, and then cooled to room temperature at 10°C/min, incineration of the resin component in the paste (debinder treatment) and fixing of the sealing material A sealing material layer was formed on the alkali glass substrate. Next, on the alkali-free glass substrate having the sealing material layer, another alkali-free glass substrate (□40 mm × 0.5 mm thick) on which the sealing material layer is not formed is accurately overlapped, and then from the alkali-free glass substrate side having the sealing material layer. By irradiating a laser beam with a wavelength of 808 nm along the sealing material layer, the sealing material layer was softened and flowed, and the alkali-free glass substrates were hermetically sealed. In addition, the laser beam irradiation conditions (output, irradiation speed) were adjusted according to the average thickness of the sealing material layer. Finally, after dropping the obtained sealing structure onto concrete from 1 m above, "○" indicates that no peeling occurred at the interface between the alkali free glass and the sealing material layer, and the interface between the alkali free glass and the sealing material layer was partially peeled off. The sealing strength was evaluated as "(triangle|delta)", the thing in which the interface of the alkali free glass and the sealing material layer completely peeled, and "x".

Confidentiality was evaluated as follows. The sealing structure obtained by the above method was maintained for 24 hours in a constant temperature and humidity chamber maintained at 121°C, 100% humidity, and 2 atm. After that, the sealing structure was observed with an optical microscope to indicate that the sealing material layer did not deteriorate and moisture did not penetrate into the sealing structure, indicating that “○”, and no penetration of moisture into the sealing structure was confirmed, but the sealing material layer was deteriorated. The airtightness was evaluated as "Δ", and "x" when moisture intrusion into the sealing structure was confirmed.

As can be seen from Table 1, in Samples No. 1 to 6, since the glass composition of the glass powder was regulated within a predetermined range, the evaluation of the coefficient of thermal expansion, the light absorption rate, the softening fluidity, the sealing strength, and the airtightness was good. On the other hand, Sample No. 7 has a small molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO), so during firing and laser sealing At the time, devitrification occurred, and due to this devitrification, evaluation of softening fluidity was poor, making it impossible to evaluate sealing strength and airtightness. Sample No. 8 had a large molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO), so the light absorption rate was low, so sealing strength and airtightness were low. evaluation was not good. Sample No. 9 has a low light absorptivity due to a low content of Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO+CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO, and evaluation of fluidity, adhesive strength, and airtightness was bad Sample No. 10 has a large molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO), so the light absorption rate is low, so sealing strength and airtightness are low. evaluation was not good. In addition, sample No. 8 had a rather high coefficient of thermal expansion because the molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO) was too large. .

For reference, for sample No. 3, 7.5 vol% of refractory filler powder was added to the laser absorber (Fe ₂ O ₃ -Cr ₂ O ₃ -MnO-based composite oxide, average particle diameter D ₅₀ 1.0 μm, maximum particle diameter D _max 3.0 μm), the coefficient of thermal expansion increased to 77 × 10 ^-7 /°C.

(industrial applicability)

The bismuth-based glass of the present invention and a sealing material using the same are used for laser sealing of organic EL devices such as organic EL displays and organic EL lighting devices, as well as laser sealing of solar cells such as dye-sensitized solar cells and CIGS thin-film compound solar cells; It is also suitable for laser sealing of airtight packages such as MEMS packages and LED packages.

Claims (11)

As a glass composition, it is Bi2O3 25-45%, _B2O3 20-35%, _{Bi2O3 + B2O3 +} BaO+ZnO+CuO+MnO _{+ Fe2O3} +TiO2 _{+ V2O5 + Cr2O in} mole% _of the following oxide conversion _{. 3} +Co ₃ O ₄ +NiO 90-100% (however, 90% is not included), the molar ratio (Bi ₂ O ₃ +B ₂ O ₃ +BaO+ZnO)/(CuO+MnO+Fe ₂ O ₃ +TiO ₂ +V ₂ O ₅ +Cr ₂ O ₃ +Co ₃ O ₄ +NiO) bismuth-based glass, characterized in that 2.0 to 2.81. The method of claim 1,
A bismuth-based glass having a ZnO content of 1 to 20 mol%. 3. The method according to claim 1 or 2,
A bismuth-based glass having a MnO content of 3 to 25 mol%. 3. The method according to claim 1 or 2,
A bismuth-based glass substantially free of PbO. A method for producing the bismuth-based glass according to claim 1 or 2, comprising:
A method for producing a bismuth-based glass, comprising: melting and molding a glass batch containing any one of a nitrate raw material, a sulfate raw material, a dioxide raw material, and a peroxide raw material to produce a bismuth-based glass. 6. The method of claim 5,
A method for producing a bismuth-based glass, wherein the raw material for oxide is a raw material for manganese dioxide. 6. The method of claim 5,
A method for producing a bismuth-based glass, wherein the peroxide raw material is a permanganate raw material. A sealing material comprising a glass powder made of bismuth glass and a refractory filler powder, the sealing material comprising:
A sealing material characterized in that the content of the glass powder is 50 to 95 vol%, the content of the refractory filler powder is 1 to 40 vol%, and the bismuth-based glass is the bismuth-based glass according to claim 1 or 2. 9. The method of claim 8,
Refractory filler powder is one or more selected from cordierite, willemite, alumina, zirconium phosphate compound, zircon, zirconia, tin oxide, quartz glass, β-eucryptite, and spodumene. ingredient. 9. The method of claim 8,
A sealing material characterized in that the content of the laser absorber is 5% by volume or less. 9. The method of claim 8,
A sealing material for use in laser sealing.