JP6840982B2 - Bismuth glass and sealing materials using it - Google Patents

Description

The present invention relates to a bismuth-based glass and a sealing material using the same, and particularly to a bismuth-based glass suitable for a sealing treatment by laser light (hereinafter, laser sealing) and a sealing material using the same.

In recent years, an organic EL display has been attracting 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 infiltration of gas and moisture, the active element and the organic light emitting layer having low water resistance are liable to deteriorate, and the display characteristics of the organic EL display deteriorate with time. Was occurring.

On the other hand, the sealing material containing the glass powder is less likely to allow gas or moisture to permeate than the organic resin adhesive, so that the airtightness inside the organic EL display can be ensured.

However, since the glass powder has a higher softening temperature than the organic resin adhesive, there is a risk that the active element and the organic light emitting layer are thermally deteriorated at the time of sealing. Under these circumstances, laser sealing is drawing attention. According to laser sealing, it is possible to locally heat only the part to be sealed, and the sealed object such as a non-alkali glass substrate can be sealed without thermally deteriorating the active element or the organic light emitting layer. can do.

Further, in recent years, it has been studied to maintain the characteristics of the airtight package and extend the service life. For example, in an airtight package on which an LED element is mounted, a low-temperature fired substrate (LTCC) having aluminum nitride and thermal vias is used as a substrate from the viewpoint of thermal conductivity. In this case as well, the substrate and lid (lid) are used. ) Is preferably laser-sealed. In particular, in an airtight package in which an LED element that emits light in the ultraviolet wavelength region is mounted, it becomes easy to maintain the emission characteristics in the ultraviolet wavelength region by laser sealing. Further, it is possible to prevent thermal deterioration of the LED element by laser sealing. Further, even in an airtight package on which a MEMS (Micro Electric Mechanical System) element is mounted, laser sealing is preferable in order to prevent deterioration of the characteristics of the MEMS element.

U.S. Pat. No. 6416375 Japanese Unexamined Patent Publication No. 2006-315902

The sealing material used for laser sealing generally includes glass powder, refractory filler powder and laser absorber. The glass powder is a component that softens and flows during laser sealing, reacts with the object to be sealed, and secures the sealing strength. 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 absorber is a material for absorbing laser light during laser sealing and converting it into heat energy, and does not soften and flow during laser sealing.

Conventionally, lead boric acid-based glass has been used as the glass powder, but from an environmental point of view, lead-free glass has been used in recent years. In particular, bismuth-based glass has a low melting point and excellent softening fluidity, and is therefore regarded as a promising lead-free glass. However, in bismuth-based glass, the main component Bi ₂ O ₃ has almost no laser absorbing ability, so that the laser absorbing ability tends to be insufficient. Therefore, in order to supplement the laser absorption capacity of bismuth-based glass, the content of the laser absorber must be increased. However, when the content of the laser absorber increases, the laser absorber melts into the bismuth-based glass at the time of laser sealing, which causes the bismuth-based glass to devitrify and the desired softening fluidity cannot be secured. ..

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

As a result of diligent studies, the present inventor has found that the above technical problems can be solved by introducing predetermined amounts of CuO and MnO into bismuth-based glass, and proposes the present invention. In other words, bismuth glass of the present invention has a glass composition, in mol% terms of _oxide, and contains _{Bi 2 O 3 25~45%, B} 2 O 3 20~35%, a 15 to 40% CuO + MnO, Moreover, the molar ratio CuO / MnO is 0.5 to 6.2. Here, "CuO + MnO" refers to the total amount of CuO and MnO. “CuO / MnO” refers to a value obtained by dividing the content of CuO by the content of MnO.

The bismuth-based glass of the present invention contains 20 mol% or more of CuO and MnO in the glass composition in total. CuO and MnO are components that greatly enhance the laser absorption capacity. Therefore, if the total amount of CuO and MnO is regulated to 20 mol% or more, the laser absorption capacity can be remarkably enhanced. In particular, the ability to absorb laser light having a wavelength of 808 nm, which is widely used industrially, can be remarkably enhanced.

According to the investigation by the present inventors, the _{raw material for introducing MnO such as MnO 2} has an oxidizing action at the time of melting. Then, as bismuth glass of the present invention, a combination of CuO and MnO, when regulating the molar ratio CuO / MnO to 0.5 to 6.2, Cu ₂ O present in the glass during melting, the MnO Copper oxide (for example, CuO) having an oxidation number of 2 or more is oxidized by the introduced raw material, and this increases the laser absorption capacity in the near infrared wavelength region.

As described above, the bismuth-based glass of the present invention has an extremely high laser absorption capacity because the total amount of CuO and MnO is 20 mol% or more and the molar ratio CuO / MnO is regulated to 0.5 to 6.2. It is expensive, and when used as a sealing material, the amount of laser absorber introduced can be reduced as much as possible. As a result, both softening fluidity and laser absorption capacity can be achieved at a high level.

Secondly, the bismuth-based glass of the present invention preferably further contains 1 to 20 mol% of ZnO in the glass composition.

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

Fourth, the bismuth-based glass of the present invention preferably contains substantially no PbO. Here, "substantially free of PbO" refers to a case where the content of PbO in the glass composition is less than 0.1% by mass.

Fifth, the sealing material of the present invention is a sealing material containing a glass powder made of bismuth-based glass and a fire-resistant filler powder, in which the glass powder content is 50 to 95% by volume and the fire-resistant filler powder is contained. It is preferable that the amount is 1 to 40% by volume and the bismuth-based glass is the above-mentioned bismuth-based glass.

Sixth, in the sealing material of the present invention, the refractory filler powder is made from cordierite, willemite, alumina, zirconium phosphate compound, zircon, zirconia, tin oxide, quartz glass, β-eucryptite, and spodium. It is preferably one or more selected.

Seventh, the sealing material of the present invention preferably has a laser absorber content of 5% by volume or less.

Eighth, the sealing material of the present invention is preferably used for laser sealing. By doing so, it is possible to prevent thermal deterioration of the element at the time of sealing. The light source of the laser light used for laser sealing is not particularly limited, but for example, a semiconductor laser, a YAG laser, a CO ₂ laser, an excimer laser, an infrared laser and the like are suitable because they are easy to handle. Further, the emission center wavelength of the laser light is preferably 500 to 1600 nm, particularly preferably 750 to 1300 nm in order for the sealing material to accurately absorb the laser light.

Bismuth glass of the present invention has a glass composition, in _{mol%, Bi 2 O 3 25~45%} , B 2 O 3 20~35%, containing 15 to 40% CuO + MnO, is and the molar ratio CuO / MnO It is characterized by being 0.5 to 6.2. The reasons for limiting the glass composition range of bismuth-based glass as described above are shown below. In the description of the glass composition, the% indication indicates mol%.

Bi ₂ O ₃ is a main component of 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%, and more preferably 35 to 40%. If _{the content of Bi 2} O ₃ is too small, the softening point becomes too high, and even if the glass is irradiated with laser light, it becomes difficult for the glass to soften and flow. On the other hand, if _{the content of Bi 2} O ₃ is too large, the coefficient of thermal expansion becomes unreasonably high, cracks occur in the object to be sealed and the material layer to be sealed during laser sealing, and poor airtightness is likely to occur. Become. In addition, the glass becomes thermally unstable, and the glass tends to be devitrified when the laser is sealed.

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%, and more preferably 24 to 30%. If _{the content of B 2} O ₃ is too small, the glass becomes thermally unstable and the glass tends to be devitrified during laser sealing. On the other hand, if _{the content of B 2} O ₃ is too large, the softening point becomes too high, and even if the glass is irradiated with laser light, the glass becomes difficult to soften and flow.

CuO and MnO are components that greatly enhance the laser absorption capacity. The total amount of CuO and MnO is 20 to 40%, preferably 22 to 35%, and more preferably 25 to 30%. If the total amount of CuO and MnO is too small, the laser absorption capacity tends to decrease. On the other hand, if the total amount of CuO and MnO is too large, the softening point becomes too high, and even if laser light is irradiated, the glass becomes difficult to soften and flow. In addition, the glass becomes thermally unstable, and the glass tends to be devitrified when the laser is sealed. The CuO content is preferably 8 to 30%, more preferably 13 to 25%. The MnO content is preferably 3 to 25%, more preferably 5 to 15%.

MnO- _{introduced raw materials such as MnO 2} have an oxidizing action when melted. Then, the bismuth glass, a combination of CuO and MnO, when regulating the molar ratio CuO / MnO in .5-6.2, Cu ₂ O present in the glass during melting, is oxidized by the introduction material of MnO As a result, copper oxide having an oxidation number of 2 or more increases, which can greatly enhance the laser absorption capacity in the near-infrared wavelength region. The molar ratio CuO / MnO is 0.5 to 6.2, preferably 0.7 to 6.0, and more preferably 1.0 to 3.5. If the molar ratio CuO / MnO is too small, the glass becomes thermally unstable and the glass tends to be devitrified during laser sealing. On the other hand, when the molar ratio CuO / MnO too large, Cu 2 _O is not sufficiently oxidized during melting, it becomes difficult to obtain a desired laser absorption capacity.

ZnO is a component that lowers the coefficient of thermal expansion. The ZnO content is preferably 0 to 25%, more preferably 1 to 20%, still more preferably 5 to 15%. If the ZnO content is too low, the coefficient of thermal expansion tends to be high. On the other hand, if the content of ZnO is too large _{, the glass becomes thermally unstable when the content of Bi 2} O ₃ is 35% or more, and the glass tends to be devitrified at the time of laser sealing.

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

Fe ₂ O ₃ is a component that enhances the laser absorption capacity, and further, is a component that suppresses devitrification during laser sealing when the content of _{Bi 2} O _{3 is 35% or more.} The content of Fe ₂ O ₃ is preferably 0 to 5%, 0.1 to 3%, and particularly 0.2 to 2%. If _{the content of Fe 2} O ₃ is too large, the component balance in the glass composition is impaired, and conversely, the glass tends to be devitrified.

Al ₂ O ₃ is a component that enhances water resistance. Its content is preferably 0 to 5%, 0 to 3%, particularly 0.1 to 2%. If _{the content of Al 2} O ₃ is too large, the softening point becomes too high, and even if the glass is irradiated with laser light, it becomes difficult for the glass to soften and flow.

MgO, CaO, SrO and BaO are components that enhance thermal stability. However, if the contents of MgO, CaO, SrO and BaO are too large, it becomes difficult to reduce the coefficient of thermal expansion while ensuring the softening fluidity. Therefore, the total amount and individual content of MgO, CaO, SrO and BaO are preferably 0 to 7%, 0 to 5%, 0 to 3%, less than 0 to 2%, 0 to 1%, and particularly 0 to 1. Less than%.

SiO ₂ is a component that enhances water resistance. Its content is preferably 0 to 10%, 0 to 5%, and particularly preferably less than 0 to 1%. If _{the content of SiO 2} is too large, the softening point becomes too high, and even if the glass is irradiated with laser light, it becomes difficult for the 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 the effect of promoting devitrification during melting. Therefore, the total content of these components is preferably 2% or less, particularly preferably less than 1%.

P ₂ O ₅ is a component that suppresses devitrification during melting, but if the amount added is too large, the glass tends to be phase-separated during 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 phase separation during melting, but if the content of La ₂ O ₃ , Y ₂ O ₃ and Gd ₂ O ₃ is too high, , The softening point becomes too high, and even if laser light is irradiated, the glass becomes difficult to soften. Therefore, _{the contents of La 2} O ₃ , Y ₂ O ₃ and Gd ₂ O ₃ are preferably 0 to 5%, particularly preferably less than 0 to 1%, respectively.

TiO ₂ , V ₂ O ₅ , Cr ₂ O ₃ , Co ₂ O ₃ , MoO ₃ , NiO and CeO ₂ are components that enhance the laser absorption capacity. The content of each component is preferably 0-7%, 0-4%, particularly less than 0-1%. If the content of each component is too high, the glass tends to be devitrified during laser sealing.

From an environmental point of view, PbO is preferably substantially free.

The sealing material of the present invention is a sealing material containing a glass powder made of bismuth-based glass and a fire-resistant filler powder, in which the content of the glass powder is 50 to 95% by volume and the content of the fire-resistant filler powder is 1 to 1. It is preferable that the volume is 40% and the bismuth-based glass is the above-mentioned 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 low, the softening fluidity of the sealing material tends to decrease. On the other hand, if the content of the glass powder is high, the content of the refractory filler powder is relatively low, and the coefficient of thermal expansion of the sealing material may be unreasonably high.

The maximum particle size D _max of the glass powder is preferably 10 μm or less, particularly 5 μm or less. If the maximum particle size D _max of the glass powder is too large, the time required for laser sealing becomes long, it becomes difficult to make the gap between the objects to be sealed uniform, and the accuracy of laser sealing tends to decrease. Here, the "maximum particle size D _max " refers to a value measured by a laser diffractometer, and the cumulative amount is accumulated from the smallest particle in the volume-based cumulative particle size distribution curve measured by the laser diffractometer. The particle size is 99%.

The softening point of the glass powder is preferably 480 ° C. or lower, 450 ° C. or lower, and particularly preferably 350 to 430 ° C. If the softening point of the glass powder is too high, it becomes difficult for the glass to soften during laser sealing, so that the sealing strength cannot be increased unless the output of the laser beam is increased. Here, the "softening point" refers to the temperature of the fourth inflection point as measured by macro-type differential thermal analysis.

For the glass powder, for example, a glass batch containing various raw materials is prepared, put into platinum melting, melted at 900 to 1200 ° C. for 1 to 3 hours, and then the molten glass is poured between water-cooled twin rollers to form a film. It is produced by molding into a shape, crushing the obtained glass film with a ball mill, and performing classification such as air classification.

It is preferable to use one or more of nitrates, sulfates, dioxides, and peroxide salts as a part of the raw materials used for producing the glass powder. Among the coloring components, there is a component (particularly CuO) whose laser absorption capacity increases when the oxidation number is high. Then, by using such a raw material, the oxidation number of the coloring component in the molten glass can be increased.

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, and particularly 22 to 35% by volume. If the content of the refractory filler powder is low, the coefficient of thermal expansion of the sealing material may be unreasonably high. On the other hand, when the content of the refractory filler powder is large, the content of the glass powder is relatively small, and the softening fluidity of the sealing material tends to decrease.

Various materials can be used as the refractory filler powder. Among them, cordierite, willemite, alumina, zirconium phosphate compound, zircon, zirconia, tin oxide, quartz glass, β-eucryptite, and spojumen. One or more selected from the above is preferable. These refractory filler powders have a low coefficient of thermal expansion, high mechanical strength, and good compatibility with the bismuth-based glass of the present invention. Further, β-eucryptite is particularly preferable because it has a high effect of lowering the coefficient of thermal expansion of the sealing material.

The maximum particle size D _max of the refractory filler powder is preferably 15 μm or less, less than 10 μm, less than 5 μm, and particularly less than 0.5 to 3 μm. If the maximum particle size D _max of the refractory filler powder is too large, it becomes difficult to make the gap between the objects to be sealed uniform, and it becomes difficult to narrow the gap between the objects to be sealed, making the organic EL display and the airtight package thinner. It becomes difficult to plan. If the gap between the objects to be sealed is large and the difference in the coefficient of thermal expansion between the objects to be sealed and the material layer to be sealed is large, cracks or the like are likely to occur in the objects to be sealed or the material layer to be sealed.

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, and particularly 0 to 0.1% by volume. If the content of the laser absorber is too large, the laser absorber melts into the glass during laser sealing, which causes the glass to devitrify and the softening fluidity of the sealing material tends to decrease.

In the sealing material of the present invention, the light absorption rate in monochromatic light having a wavelength of 808 nm is preferably 75% or more, more preferably 80% or more. If this light absorption rate is low, the sealing material layer cannot properly absorb light at the time of laser sealing, and the sealing strength cannot be increased unless the output of the laser light is increased. If the output of the laser beam is increased, the element may be thermally deteriorated at the time of laser sealing. Here, the "light absorption rate in monochromatic light having a wavelength of 808 nm" is obtained by measuring the reflectance and transmittance of monochromatic light having λ = 808 nm with a spectrophotometer for the sealing material layer fired to a film thickness of 5 μm, respectively. Corresponds to the value obtained by subtracting the total value of 100%.

In the sealing material of the present invention, the coefficient of thermal expansion is preferably 75 × ^10-7 / ° C. or lower, particularly 50 × ^10-7 / ° C. or higher, and 71 × ^10-7 / ° C. or lower. In this way, when the object to be sealed has a low expansion, the stress remaining on the object to be sealed or the material layer for sealing becomes small, so that cracks are less likely to occur in the material layer to be sealed or the material to be sealed. Here, the "coefficient of thermal expansion" refers to a value measured by a push rod type thermal expansion coefficient measuring (TMA) device, and the measured temperature range is 30 to 300 ° C.

In the sealing material of the present invention, the softening point is preferably 510 ° C. or lower, 480 ° C. or lower, and 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 beam is increased.

The sealing material of the present invention may be used 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. Vehicles are mainly composed of solvents and resins. The resin is added for the purpose of adjusting the viscosity of the sealing material paste. Further, if necessary, a surfactant, a thickener and the like can be added. The sealing material paste is applied onto the object to be sealed using a coating machine such as a dispenser or a screen printing machine, and then subjected to a debindering step.

As the resin, acrylic acid ester (acrylic resin), ethyl cellulose, polyethylene glycol derivative, nitrocellulose, polymethylstyrene, polyethylene carbonate, methacrylic acid ester and the like can be used. In particular, acrylic ester and nitrocellulose are preferable because they have good thermal decomposability.

As solvents, N, N'-dimethylformamide (DMF), α-terpineol, higher alcohol, γ-butyl lactone (γ-BL), tetraline, butyl carbitol 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.

The present invention will be described in detail based on examples. The following examples are merely examples. The present invention is not limited to the following examples.

Tables 1 and 2 show Examples (Samples Nos. 1 to 6) and Comparative Examples (Samples Nos. 7 to 11) of the present invention.

The glass powders listed in the table were prepared as follows. First, a glass batch containing various raw materials was prepared so as to have the glass composition shown in the table, and this was placed in a platinum crucible and melted at 1000 ° C. for 1 hour. At the time of melting, the molten glass was homogenized by stirring with a platinum rod. Next, a part of the obtained molten glass was poured between water-cooled twin rollers to form a film, and the remaining molten glass was poured into a carbon mold to form a rod. Finally, the obtained glass film was pulverized by a ball mill and then classified by an air classifier so that _{the average particle diameter D 50} was 1.0 μm and the maximum particle diameter D _{max was 4.0 μm.} Further, the rod-shaped glass was put into an electric furnace kept at a temperature about 20 ° C. higher than the slow cooling point, and then slowly cooled to room temperature at a temperature lowering rate of 3 minutes / minute.

Β-eucryptite was used as the refractory filler powder. The refractory filler powder is adjusted to an average particle size D of ₅₀ 1.0 μm and a maximum particle size of D _{max 3.0 μm by air classification.}

The glass powder and the refractory filler powder were mixed at the mixing ratio shown in the table, and the sample No. 1 to 11 were prepared. Sample No. For 1 to 11, the coefficient of thermal expansion, light absorption rate, softening fluidity, sealing strength and airtightness were evaluated. In addition, "N / A" in the table means that evaluation is impossible.

The coefficient of thermal expansion is a value measured by a TMA device in a temperature range of 30 to 300 ° C. As the TMA measurement sample, each sample was densely sintered and then processed into a predetermined shape.

The light absorption rate was measured as follows. First, each sample and vehicle (tripropylene glycol monobutyl ether containing ethyl cellulose resin) are uniformly kneaded with a three-roll mill to form a paste, and then an alkali-free glass substrate (OA-10, 40 mm × manufactured by Nippon Electric Glass Co., Ltd.). It was applied to a 30 mm × 30 mm square on (40 mm × 0.5 mm thick) and dried in a drying oven at 120 ° C. for 10 minutes. Next, the temperature was raised from room temperature at 10 ° C./min, fired at 510 ° C. for 10 minutes, then lowered to room temperature at 10 ° C./min, and fixed on a glass substrate. Subsequently, the reflectance and transmittance of monochromatic light having a wavelength of λ = 808 nm were measured with a spectrophotometer for the obtained fired film having a thickness of 5 μm, and the total value of these was subtracted from 100% to absorb light. It was a rate.

For softening fluidity, for each sample, ^{a powder having a mass equivalent to 0.6 cm 3} minutes was dry-pressed with a mold into a button shape with an outer diameter of 20 mm, and this was pressed onto an alumina substrate having a thickness of 25 mm × 25 mm × 0.6 mm. Evaluate by placing, raising the temperature in air at a rate of 10 ° C./min, holding at 510 ° C. for 10 minutes, lowering the temperature to room temperature at 10 ° C./min, and measuring the diameter of the obtained button. It was done. Specifically, the case where the flow diameter was 16.0 mm or more was evaluated as “◯”, and the case where the flow diameter 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 with a three-roll mill to form a paste, and then an alkali-free glass substrate (OA-10 manufactured by Nippon Denki Glass Co., Ltd., □ 40 mm x 0.5 mm thick, coefficient of thermal expansion 38 x ^10-7 / ° C), coated in a frame shape (5 μm thick, 0.6 mm width) along the edge of the non-alkali glass substrate, and 120 in a drying oven. The temperature was dried for 10 minutes. Next, the temperature is raised from room temperature at 10 ° C./min, fired at 510 ° C. for 10 minutes, and then lowered to room temperature at 10 ° C./min to incinerate the resin components in the paste (debinder treatment) and to seal the sealing material. Fixing was performed to form a sealing material layer on a non-alkali glass substrate. Next, another non-alkali glass substrate (□ 40 mm × 0.5 mm thick) on which the sealing material layer is not formed is accurately overlaid on the non-alkali glass substrate having the sealing material layer, and then sealed. By irradiating a laser beam having a wavelength of 808 nm from the non-alkali glass substrate side having the material layer along the sealing material layer, the sealing material layer was softened and flowed, and the non-alkali glass substrates were air-sealed. .. The irradiation conditions (output, irradiation speed) of the laser beam were adjusted according to the average thickness of the sealing material layer. Finally, after the obtained sealing structure was dropped onto concrete from 1 m above, the one in which no peeling occurred at the interface between the non-alkali glass and the sealing material layer was marked with "○", and the non-alkali glass was sealed. The sealing strength was evaluated as "Δ" when the interface of the coating material layer was partially peeled off and "x" when the interface between the non-alkali glass and the sealing material layer was completely peeled off.

The airtightness was evaluated as follows. The sealed structure obtained by the above method was held 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, and the one in which the sealing material layer did not deteriorate and no moisture invaded into the sealing structure was marked with "○", and the intrusion of moisture into the sealing structure. However, the airtightness was evaluated as "Δ" for the altered sealing material layer and "x" for the invasion of water into the sealing structure.

As can be seen from Table 1, the sample No. In Nos. 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. In No. 7, since the molar ratio CuO / MnO was large, the light absorption rate was low, and the evaluation of sealing strength and airtightness was slightly inferior. Sample No. In No. 8, since the molar ratio CuO / MnO was small, devitrification occurred during firing and laser sealing, and the devitrification caused poor evaluation of softening fluidity, sealing strength, and airtightness. Sample No. In No. 9, since the total amount of CuO and MnO was small, the light absorption rate was low, and the evaluation of sealing strength and airtightness was poor. Sample No. In No. 10, since the total amount of CuO and MnO was large, the sealing material layer was insufficiently sintered, and all evaluations were impossible. Sample No. Since _{the content of Bi 2} O ₃ was high in No. 11, all evaluations were impossible due to devitrification.

The bismuth-based glass of the present invention and the sealing material using the same include dye-sensitized solar cells and CIGS-based thin film compound solar cells, in addition to laser sealing of organic EL devices such as organic EL displays and organic EL lighting devices. It is also suitable for laser sealing of solar cells such as OLED packages, laser sealing of airtight packages such as OLED packages and LED packages, and the like.

Claims (8)

As a glass composition, in mol% terms of _{oxide, Bi 2 O 3 25~45%,} B 2 O 3 20~35%, containing 15 to 40% CuO + MnO, is and the molar ratio CuO / MnO 0.5 Bismuth-based glass characterized by being ~ 6.2. The bismuth-based glass according to claim 1, further comprising 1 to 20 mol% of ZnO in the glass composition. The bismuth-based glass according to claim 1 or 2, wherein the MnO content is 3 to 25 mol%. The bismuth-based glass according to any one of claims 1 to 3, wherein the content of PbO in the glass composition is less than 0.1% by mass. In a sealing material containing a glass powder made of bismuth-based glass and a refractory filler powder,
The bismuth-based glass according to any one of claims 1 to 4, wherein the content of the glass powder is 50 to 95% by volume, the content of the refractory filler powder is 1 to 40% by volume, and the bismuth-based glass is. A sealing material that is characterized by that. The refractory filler powder is one or more selected from cordierite, willemite, alumina, zirconium phosphate compound, zircon, zirconia, tin oxide, quartz glass, β-eucryptite, and spodium. The sealing material according to claim 5. The sealing material according to claim 5 or 6, wherein the content of the laser absorber is 5% by volume or less. The sealing material according to any one of claims 5 to 7, wherein the sealing material is used for laser sealing.