JP5224102B2 - Sealing material for organic EL display - Google Patents

Description

  The present invention relates to a sealing material for an organic EL display that is subjected to a sealing treatment with a laser beam.

  In recent years, organic EL displays have attracted attention as flat display panels. Since the organic EL display can be driven by a DC voltage, the driving circuit can be simplified, and there are advantages such as a liquid crystal display that is not dependent on the viewing angle, bright due to self-emission, and has a high response speed. Currently, organic EL displays are mainly used in small portable devices such as mobile phones, but in the future, application to ultra-thin televisions is expected.

  The organic EL display is composed of two glass substrates, a negative electrode such as metal, an organic light emitting layer, a positive electrode such as ITO, and an adhesive material. Conventionally, an organic resin adhesive material such as an epoxy resin having a low temperature curability or an ultraviolet curable resin has been used as the adhesive material. However, since it is difficult for organic resin adhesive materials to completely block gas intrusion, it is difficult to maintain the airtightness inside the organic EL display, resulting in low water resistance. The organic light emitting layer is likely to be deteriorated, resulting in a problem that the display characteristics of the organic EL display deteriorate with time. In addition, the organic resin adhesive material has the advantage that the glass substrates can be bonded to each other at a low temperature, but has the disadvantage that the water resistance is low, and when the organic EL display is used for a long time, the reliability of the display is lowered. It becomes easy.

In the organic EL display, as in the liquid crystal display, an active element such as a thin film transistor (TFT) is disposed in each pixel and driven.
US Pat. No. 6,416,375 JP 2006-315902 A

  A sealing material using glass is excellent in water resistance as compared with an organic resin adhesive material and is suitable for ensuring airtightness inside the organic EL display.

  However, since the glass used for the sealing material generally has a softening point of 300 ° C. or higher, it has been difficult to apply to an organic EL display. That is, when sealing glass substrates with the above-described sealing material, it is necessary to put the entire organic EL display in an electric furnace and heat-treat at a temperature equal to or higher than the softening point of the glass. However, since the active element has only a heat resistance of about 120 to 130 ° C., sealing the glass substrates with this method causes the active element to be damaged by heat and deteriorate the display characteristics of the organic EL display. End up. Similarly, since the organic light emitting material also has poor heat resistance, sealing the glass substrates by this method damages the organic light emitting material due to heat and degrades the display characteristics of the organic EL display.

  In view of such circumstances, in recent years, a method for sealing an organic EL display by irradiating a sealing material with laser light has been studied. Since the laser beam can locally heat only the site to be sealed, it is possible to seal the glass substrates together while preventing deterioration of the active element or the like.

  Patent Documents 1 and 2 describe a method of sealing a front glass substrate and a rear glass substrate of a field emission display by irradiating a sealing material with laser light. However, Patent Documents 1 and 2 do not specifically describe the material configuration of the sealing material. Even if the sealing material is irradiated with laser light, the light energy of the laser light is converted into thermal energy at the sealing site. It was difficult to convert efficiently. Therefore, in order to seal glass substrates together using these sealing materials, it is necessary to increase the output of laser light, and as a result, an unreasonable thermal history is applied to the active elements and the like, and the organic EL display There was a possibility that the display characteristics of the display deteriorated.

  Therefore, the present invention has a technical problem to produce a highly reliable organic EL display by creating a sealing material for an organic EL display suitable for local heating by laser light.

As a result of diligent efforts, the present inventor has found that the above technical problem can be solved by containing a predetermined amount of bismuth-based glass powder and pigment in the sealing material, and proposes as the present invention. That is, the sealing material for organic EL displays of the present invention is a sealing material for organic EL displays that is subjected to sealing treatment with laser light, and contains 50 to 99.9% by mass of glass powder and 0% of inorganic pigment. 0.1 to 20% by mass, and the glass powder contains 5 to 50% Bi ₂ O ₃ , 10 to 50% B ₂ O ₃ , and 5 to 55% ZnO as a glass composition . wherein the average particle diameter _{D 50} is 0.01 to 5 [mu] m.

  The sealing material for organic EL displays of the present invention is subjected to sealing treatment with laser light. In this way, only the part to be sealed can be locally heated, and thermal damage to the active element and the organic light emitting layer can be prevented. In addition, when carrying out local heating with a laser beam, the temperature of the site | part 1 mm away from the heating location will be 100 degrees C or less, and the thermal damage of an active element or an organic light emitting layer can be prevented.

The sealing material for organic EL display of the present invention can use various lasers. In particular, semiconductor lasers, YAG lasers, CO ₂ lasers, excimer lasers, infrared lasers, etc. are easy to handle. preferable.

The sealing material for organic EL displays of the present invention contains 50 to 99.9% by mass of glass powder as an essential component. In this way, it is possible to maintain the airtightness inside the organic EL display, that is, to prevent a situation in which H ₂ O, O ₂ or the like that deteriorates the organic light emitting layer enters the organic EL display. Long-term reliability of the EL display can be ensured. In addition, when content of glass powder is less than 50 mass%, the fluidity | liquidity of a sealing material will become scarce and it will become difficult to raise the sealing strength of members.

  The sealing material for organic EL displays of the present invention contains an inorganic pigment as an essential component. In this way, since the light energy of the laser light can be efficiently converted into heat energy, only the part to be sealed can be locally heated. As a result, it is possible to seal the glass substrates together while preventing the active element and the organic light emitting layer from being thermally damaged. On the other hand, the sealing material for organic EL displays of the present invention regulates the content of inorganic pigment to 20% by mass or less. If it does in this way, the situation where glass devitrifies at the time of irradiation of a laser beam can be prevented.

In the sealing material for organic EL display of the present invention, the inorganic pigment is a composite oxide, C, Co ₃ O ₄ , CuO, Cr ₂ O ₃ , Fe ₂ O ₃ (including FeO), MnO ₂ , SnO, NiO. , Ti _n O _2n-1 (where n is an integer) is preferably one or more. Here, the “composite oxide” is an oxide composed of a combination of two or more kinds of oxides, and each metal ion forms an equal ion lattice in the close-packed gap of O ^2−. It refers to the oxide that forms. Since these inorganic pigments are excellent in color developability, the light energy of laser light can be efficiently converted into thermal energy.

In the sealing material for an organic EL display of the present invention, the inorganic pigment includes an Al—Co composite oxide, an Al—Co—Cr composite oxide, an Al—Cr—Fe—Zn composite oxide, an Al—Co—. Li-Ti complex oxide, Al-Cu-Fe-Mn complex oxide, Al-Fe-Mn complex oxide, Al-Si complex oxide, Ba-Ni-Ti complex oxide, Ca- Cr-Si-Sn composite oxide, Co-Cr composite oxide, Co-Cr-Fe-Mn composite oxide, Co-Cr-Fe-Ni composite oxide, Co-Cr-Fe-Ni- Si-Zr composite oxide, Co-Cr-Fe composite oxide, Co-Cr-Fe-Mn composite oxide, Co-Cr-Fe-Ni-Zn composite oxide, Co-Fe composite oxide Co-Fe-Mn-Ni complex oxide, Co-Li-P complex Oxide, Co-Ni-Si-Zr composite oxide, Co-Ni-Nb-Ti composite oxide, Co-Ni-Sb-Ti composite oxide, Co-Ni-Ti-Zn composite oxide Co-Si complex oxide, Co-Si-Zn complex oxide, Co-Ti complex oxide, Cr-Cu complex oxide, Cr-Cu-Mn complex oxide, Cr-Fe complex Oxide, Cr—Fe—Mn composite oxide, Cr—Fe—Zn composite oxide, Cr—Nb—Ti composite oxide, Cr—Sb—Ti composite oxide, Fe—Cr composite oxide Fe-Mn complex oxide, Fe-Ti complex oxide, Fe-Ti-W complex oxide, Fe-Ti-Zn complex oxide, Fe-Zn complex oxide, Ni-Nb-Ti -Based complex oxide, Ni-Sb-Ti-based complex oxide, Ni-Ti-W-based complex acid Things, it is preferable that one or two or more selected from Sb-Sn-based composite oxide. Here, “... Complex oxide” refers to a complex oxide containing an explicit component as an essential component.

The sealing material for an organic EL display of the present invention contains glass powder as a glass composition in mol%, Bi ₂ O ₃ 5-60%, B ₂ O ₃ 10-50%, ZnO 5-55%. Characterized by

The organic EL sealing material for a display of the present invention preferably has a thermal expansion coefficient of 85 × 10 -7 ^/ ℃ or less. Here, the “thermal expansion coefficient” refers to a value measured in a temperature range of 30 to 300 ° C. by a push rod type thermal expansion coefficient measurement (TMA) apparatus.

The organic EL sealing material for a display of the present invention preferably has a softening point of 600 ° C. or less. Here, the “softening point” refers to a value measured with a macro-type differential thermal analysis (DTA) apparatus, DTA starts measurement from room temperature, and the rate of temperature rise is 10 ° C./min. In addition, the softening point measured with the macro type | mold DTA apparatus points out the temperature (Ts) of the 4th bending point shown in FIG.

  In the sealing material for organic EL displays of the present invention, the content of the glass powder is 50 to 99.9% by mass, preferably 60 to 99% by mass, more preferably 75 to 98% by mass, and particularly preferably 90 to 96% by mass. %. When there is little content of glass powder, the fluidity | liquidity of a sealing material will become scarce and it will become difficult to raise the sealing strength of members. On the other hand, when the content of the glass powder is more than 99.9% by mass, the content of the inorganic pigment is relatively reduced, and it becomes difficult to convert the light energy of the laser light into heat energy. In particular, when the glass powder is alkali borosilicate glass, the content of the glass powder is preferably 90 to 98% by mass.

In the sealing material for organic EL displays of the present invention, the average particle diameter D ₅₀ of the glass powder is preferably less than 15 μm, more preferably 0.5 to 10 μm, and even more preferably 1 to ₅ μm. When the average particle diameter D ₅₀ of the glass powder is less than 15 μm, the gap between the glass substrates can be easily reduced. In such a case, even if the difference in the thermal expansion coefficient between the glass substrate and the sealing material is large, the glass substrate In addition, cracks and the like are less likely to occur at the sealing portion, and the time required for sealing can be shortened. Here, “average particle diameter D ₅₀ ” refers to a value measured by a laser diffraction method.

In the sealing material for organic EL displays of the present invention, the maximum particle diameter D _max of the glass powder is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. When the average particle diameter D _max of the glass powder is 30 μm or less, the gap between the two glass substrates is easily reduced. In such a case, even if the difference in the thermal expansion coefficient between the glass substrate and the sealing material is large, the glass substrate In addition, cracks and the like are less likely to occur at the sealing portion, and the time required for sealing can be shortened. Here, “maximum particle diameter D _max ” refers to a value measured by a laser diffraction method, and refers to a particle diameter with an integrated particle diameter of 99.9%.

The organic EL sealing material for a display of the present invention, as the glass powder, Ru using bismuth-based glass. When locally heating with laser light, if the softening point of the glass is low, the glass can be sealed in a short time and the sealing strength can be increased. However, generally, when the softening point of glass is lowered, the water resistance of the glass tends to be lowered. Therefore, it is difficult to achieve both low softening properties and high water resistance of the glass, bismuth-based glass, it is possible to achieve both the low-softening properties and high water resistance at a high level. Here , “ bismuth-based glass” refers to glass having a Bi ₂ O ₃ content of 10 mol% or more in the glass composition.

In the organic EL sealing material for a display of the present invention, the glass powder is a glass composition including, in _{mol%, Bi 2 O 3 5~50%} , B 2 O 3 10~50%, you containing 5 to 55% ZnO .

Bi ₂ O ₃ is a main component for lowering the softening point, and its content is 5 to 50%, preferably 25 to 45%. When the content of Bi ₂ O ₃ is small, the softening point of the glass becomes too high, and the glass is difficult to soften even when irradiated with laser light. On the other hand, when the content of Bi ₂ O ₃ is large, the thermal stability of the glass is lowered, and the glass is easily devitrified when irradiated with laser light.

B ₂ O ₃ is a component for forming a glass network, the content is 10-50%, preferably 15-30%. When the content of B ₂ O ₃ is small, the thermal stability of the glass is lowered, and the glass tends to be devitrified when irradiated with laser light. On the other hand, when the content of B ₂ O ₃ is large, the softening point of the glass becomes too high, and the glass is difficult to soften even when irradiated with laser light.

  ZnO is a component that suppresses devitrification of the glass during melting or laser light irradiation and lowers the thermal expansion coefficient of the glass, and its content is 5 to 55%, preferably 15 to 45%. When the content of ZnO is small, it is difficult to obtain an effect of suppressing devitrification of the glass at the time of melting or irradiation with laser light. When there is much content of ZnO, the component balance in a glass composition will be impaired, and it will become easy to devitrify glass.

  In the glass composition range, in addition to the above components, for example, the following components can be contained up to 30% in the glass composition.

SiO ₂ is a component that improves the water resistance of the glass, and its content is 0 to 20%, preferably 0 to 5%. When the content of SiO ₂ is large, the softening point of the glass becomes too high, and the glass is difficult to soften even when irradiated with laser light.

Al ₂ O ₃ is a component that improves the water resistance of the glass. Its content is 0-15%, preferably 0-5%. When the content of Al ₂ O ₃ is large, the softening point of the glass becomes too high, and the glass is difficult to soften even when irradiated with laser light.

  MgO + CaO + SrO + BaO is a component that suppresses glass devitrification during melting or laser light irradiation, and the content of MgO + CaO + SrO + BaO is 0 to 25%, preferably 0 to 20%. When there is much content of MgO + CaO + SrO + BaO, the softening point of glass will become high too much, and even if it irradiates a laser beam, glass will become difficult to soften.

  MgO is a component that suppresses glass devitrification during melting or laser light irradiation, and its content is 0 to 12%, preferably 0 to 7%. When the content of MgO is large, the softening point of the glass becomes too high, and the glass is difficult to soften even when irradiated with laser light.

  CaO is a component that suppresses glass devitrification during melting or laser light irradiation, and its content is 0 to 15%, preferably 0 to 4%. When the content of CaO is large, the softening point of the glass becomes too high, and the glass is difficult to soften even when irradiated with laser light.

  SrO is a component that suppresses the devitrification of the glass during melting or irradiation with laser light, and its content is 0 to 10%, preferably 0 to 7%. When the content of SrO is large, the softening point of the glass becomes too high, and the glass is difficult to soften even when irradiated with laser light.

  BaO is a component that suppresses devitrification of the glass during melting or laser light irradiation, and its content is 0 to 10%, preferably 0 to 8%. When there is too much content of BaO, there exists a possibility that the thermal expansion coefficient of glass may become high too much.

CeO ₂ is a component that suppresses devitrification of the glass during melting or irradiation with laser light, and its content is 0 to 10%, preferably 0 to 4%. When the content of CeO ₂ is too large, balance of components in the glass composition is impaired, the glass tends to be devitrified reversed. Further, from the viewpoint of improving the thermal stability of the glass, it is preferable to add a small amount of CeO _2. Specifically, the content of CeO ₂ is preferably 0.1% or more.

Sb ₂ O ₃ is a component for suppressing devitrification of the glass, and its content is 0 to 10%, preferably 0 to 2%. Sb ₂ O ₃ has an effect of stabilizing the glass network of bismuth-based glass. If Sb ₂ O ₃ is appropriately added to the bismuth-based glass, when the content of Bi ₂ O ₃ is large, for example, Bi ₂ O _{Even if} the content of ₃ is 35% or more, the thermal stability of the glass is hardly lowered. However, when the content of Sb ₂ O ₃ is too large, balance of components in the glass composition is impaired, the glass tends to be devitrified reversed. Further, from the viewpoint of improving the thermal stability of the glass, it is preferable to add a small amount of Sb ₂ O ₃ , and specifically, the content of Sb ₂ O ₃ is preferably 0.2% or more.

WO ₃ is a component for suppressing devitrification of glass, and its content is 0 to 15%, preferably 0 to 5%. When the content of WO ₃ is too large, balance of components in the glass composition is impaired, the glass tends to be devitrified reversed.

In ₂ O ₃ + Ga ₂ O ₃ (total amount of In ₂ O ₃ and Ga ₂ O ₃ ) is a component for suppressing devitrification of glass, and its content is 0 to 6% in total, preferably 0 to 3%. When the content of _{In 2 O 3 + Ga 2 O} 3 is too large, balance of components in the glass composition is impaired, the glass tends to be devitrified reversed.

Li ₂ O + Na ₂ O + K ₂ O is a component that lowers the softening point of the glass, but since it has an action of promoting devitrification of the glass when melted, the total amount is preferably 4% or less.

P ₂ O ₅ is a component that suppresses the devitrification of the glass at the time of melting. If the amount of P ₂ O ₅ added is more than 2%, the glass is likely to phase separate at the time of melting.

La ₂ O ₃ , Y ₂ O ₃ and Gd ₂ O ₃ are components that suppress the phase separation of the glass at the time of melting. If the total amount of these is more than 5%, the softening point of the glass becomes too high, Even when laser light is irradiated, the glass becomes difficult to soften.

  In the glass composition range, in addition to the above components, the following coloring components can be contained in the glass composition in an amount of 0 to 10%, preferably 0.2 to 8%. If a coloring component is added to the glass composition, conversion to thermal energy can be promoted upon irradiation with laser light.

  CuO is a component having light absorption characteristics, and is a component that absorbs light and softens glass when irradiated with laser light, and suppresses devitrification of glass during melting or laser light irradiation. It is a component, and its content is 0 to 15%, preferably 0 to 10%. When there is too much content of CuO, the component balance in a glass composition will be impaired, conversely, it will become easy to devitrify glass and the fluidity | liquidity of glass will be impaired easily.

Fe ₂ O ₃ is a component having light absorption characteristics. When irradiated with laser light, Fe ₂ O ₃ is a component that absorbs light and softens the glass, and devitrifies the glass during melting or laser light irradiation. The content is 0 to 6%, preferably 0 to 2%. When the content of Fe ₂ O ₃ is too large, balance of components in the glass composition is impaired, the glass is easily devitrified Conversely, the flowability of the glass is easily impaired.

  NiO is a component having light absorption characteristics, and when irradiated with laser light, it is a component that absorbs light and softens the glass, and its content is 0 to 7%, preferably 0 to 3%. is there. When there is much content of NiO, it will become easy to devitrify glass and the fluidity | liquidity of glass will be easy to be impaired.

V ₂ O ₅ is a component having light absorption characteristics, and is a component that, when irradiated with laser light, absorbs light and softens the glass, and its content is 0 to 7%, preferably 0 to 0%. 3%. When the content of V ₂ O ₅ is large, the glass tends to be foamed when irradiated with laser light.

  CoO is a component having light absorption characteristics, and is a component that absorbs light and softens the glass when irradiated with laser light, and its content is 0 to 9%, preferably 0 to 3%. is there. When there is much content of CoO, it will become easy to devitrify glass and the fluidity | liquidity of glass will be easy to be impaired.

MoO ₃ is a component having light absorption characteristics, and when irradiated with laser light, it is a component that absorbs light and softens the glass, and its content is 0 to 7%, preferably 0 to 3%. It is. When the content of MoO ₃ is large, the glass is easily devitrified, the flowability of the glass is easily impaired.

TiO ₂ is a component having light absorption characteristics, and is a component that absorbs light and softens glass when irradiated with laser light, and its content is 0 to 10%, preferably 0 to 4%. It is. When the content of TiO ₂ is large, the glass is easily devitrified, the flowability of the glass is easily impaired. If the content of TiO ₂ is large, too high softening point of the glass, be irradiated with laser light, the glass is hardly softened.

MnO ₂ is a component having light absorption characteristics, and when irradiated with laser light, it is a component that absorbs light and softens the glass, and its content is 0 to 10%, preferably 0 to 4%. It is. When the content of MnO ₂ is large, the glass is easily devitrified, the flowability of the glass is easily impaired.

In addition, it is preferable that PbO is not substantially contained from an environmental viewpoint. Here, “substantially no PbO” refers to the case where the content of PbO in the glass composition is 1000 ppm (mass) or less.

  In the sealing material for organic EL displays of the present invention, the content of the inorganic pigment is 0.1 to 20% by mass, preferably 0.5 to 20% by mass, more preferably 3 to 15% by mass, and particularly preferably 5 to 5% by mass. 12% by mass. If the content of the inorganic pigment is small, the degree of coloring at the sealing site becomes poor, and it becomes difficult to convert the light energy of the laser light into thermal energy. On the other hand, when the content of the inorganic pigment is large, the amount of the inorganic pigment dissolved into the glass becomes too large when the laser beam is irradiated, and the thermal stability of the sealing material becomes poor.

  In the sealing material for organic EL displays of the present invention, the inorganic pigment is preferably a complex oxide. Since the composite oxide is structurally stable, it is excellent in heat resistance, chemical resistance, weather resistance and safety.

In the sealing material for an organic EL display of the present invention, the inorganic pigment includes Al—Co composite oxide, Al—Co—Cr composite oxide, Al—Cr—Fe—Zn composite oxide, Al—Co—. Li-Ti complex oxide, Al-Cu-Fe-Mn complex oxide, Al-Fe-Mn complex oxide, Al-Si complex oxide, Ba-Ni-Ti complex oxide, Ca- Cr-Si-Sn composite oxide, Co-Cr composite oxide, Co-Cr-Fe-Mn composite oxide, Co-Cr-Fe-Ni composite oxide, Co-Cr-Fe-Ni- Si-Zr composite oxide, Co-Cr-Fe composite oxide, Co-Cr-Fe-Mn composite oxide, Co-Cr-Fe-Ni-Zn composite oxide, Co-Fe composite oxide , Co—Fe—Mn—Ni based composite oxide, Co—Li— -Based composite oxide, Co-Ni-Si-Zr-based composite oxide, Co-Ni-Nb-Ti-based composite oxide, Co-Ni-Sb-Ti-based composite oxide, Co-Ni-Ti-Zn-based composite oxide Oxide, Co-Si based complex oxide, Co-Si-Zn based complex oxide, Co-Ti based complex oxide, Cr-Cu based complex oxide, Cr-Cu-Mn based complex oxide, Cr-Fe -Based composite oxide, Cr-Fe-Mn-based composite oxide, Cr-Fe-Zn-based composite oxide, Cr-Nb-Ti-based composite oxide, Cr-Sb-Ti-based composite oxide, Fe-Cr-based composite oxide Oxide, Fe-Mn composite oxide, Fe-Ti composite oxide, Fe-Ti-W composite oxide, Fe-Ti-Zn composite oxide, Fe-Zn composite oxide, Ni-Nb -Ti-based composite oxide, Ni-Sb-Ti-based composite oxide, Ni-Ti-W-based If oxides, is preferably one or more selected from Sb-Sn-based composite oxide. These inorganic pigments include (Co, Fe, Mn) (Fe, Cr, Mn) ₂ O ₄ , (Ni, Co, Fe) (Fe, Cr) ₂ O ₄ , (Ni, Co, Fe) (Fe , Cr) ₂ O _4. (Zn, Fe) (Fe, Cr) ₂ O ₄ , (Co, Fe, Mn) (Fe, Cr, Mn) ₂ O ₄ , (Fe, Mn) (Fe, Mn) ₂ O ₄ (Manganese ferrite black spinel), (Fe, Mn) (Fe, Cr, Mn) O ₄ , Cu (Cr, Mn) ₂ O ₄ , CuCr ₂ O ₄ , (Co, Fe) (Fe, Cr) ₂ O ₄ , (Co, Ni) O · ZrSiO ₄ , (Sn, Sb) O ₂ , (Ni, Co, Fe) (Fe, Cr) ₂ O ₄ .ZrSiO ₄ , Fe (Fe, Cr) ₂ O ₄ , (Zn, Fe) (Fe, Cr) ₂ O ₄ , (Zn, Fe) (Fe, Cr, Al) ₂ O ₄ , (Fe, Co) Fe ₂ O ₄ , (Zn, Fe) Fe ₂ O ₄ , (Ti, Sb, Ni) O ₂ , (Ti, Sb, Cr) O ₂ , (Ti, Cr, Nb) O ₂ , (Ti, Sb, Ni, Co) O ₂ , (Ti, Nb, Ni, Co) O ₂ , (Ti, Ni, W) O ₂ , (Ti, Ni, Nb) O ₂ , (Ti, Fe, W) ) O ₂ , (Ti, Nb, Ni) O ₂ , (Zn, Fe) (Fe, Cr) ₂ O ₄ , (Fe, Zn) Fe ₂ O ₄ : TiO ₂ , (Co, Ni, Zn) TiO ₄ , CoCr ₂ O ₄ , CoAl ₂ O ₄ , CoAl ₂ O ₄ : TiO ₂ : Li ₂ O, CoSi ₂ O ₄ , Co ₂ TiO ₄ , CoLiPO ₄ , Co (Al, Cr) ₂ O ₄ , Fe ₂ TiO _{4 , Cr 2 O 3: Fe 2} O 3, (Co, Zn) 2SiO 4, 2NiO, 3BaO, 17TiO 2, CaO, SnO 2, SiO 2: mention may be made of the r ₂ O ₃ and the like.

It is preferable that the sealing material for organic EL displays of the present invention contains a black inorganic pigment. When the black inorganic pigment is used, it becomes easy to convert the light energy of the laser light into heat energy, and even if a foreign material is mixed into the sealing material, it is possible to prevent a situation in which an appearance defect is caused at the sealed portion. As the black inorganic pigment, Al-Cu-Fe-Mn composite oxide, Al-Fe-Mn composite oxide, Co-Cr-Fe composite oxide, Co-Cr-Fe-Mn composite oxide, Co-Cr-Fe-Ni composite oxide, Co-Cr-Fe-Mn composite oxide, Co-Cr-Fe-Ni-Zn composite oxide, Co-Fe-Mn-Ni composite oxide, Cr-Cu complex oxide, Cr-Cu-Mn complex oxide, Cr-Fe-Mn complex oxide, Fe-Mn complex oxide, Ti _n O _2n-1 (n is an integer), Cr ₂ O _3, C can be mentioned, for example, (Co, Fe, Mn) (Fe, Cr, Mn) 2 O 4, (Ni, Co, Fe) (Fe, Cr) 2 O 4, (Ni, Co , Fe) (Fe, Cr) 2 O 4 · (Zn, Fe) (Fe, Cr) 2 O 4, (Co, Fe, Mn _{(Fe, Cr, Mn) 2} O 4, (Fe, Mn) (Fe, Mn) 2 O 4, (Fe, Mn) (Fe, Cr, Mn) O 4, Cu (Cr, Mn) 2 O 4, CuCr ₂ O ₄ and (Co, Fe) (Fe, Cr) ₂ O ₄ may be mentioned.

Since Cr ₂ O ₃ may have an environmental impact, it is preferable that the inorganic pigment does not substantially contain Cr ₂ O ₃ . Here, “substantially does not contain Cr ₂ O ₃ ” refers to the case where the content of Cr ₂ O ₃ in the inorganic pigment is 1000 ppm (mass) or less.

In the organic EL sealing material for a display of the present invention, the average particle diameter _{D 50} of the inorganic pigment is 0.01 to 5 [mu] m, 0.1～3.5Myuemu virtuous preferable. The average particle diameter D ₅₀ of the inorganic pigment is 0.01μm smaller, upon irradiation of the laser beam, becomes the inorganic pigments tends penetration into the glass, the sealing material is easily impaired thermal stability. On the other hand, if the average particle diameter D ₅₀ of the inorganic pigment is larger than 5 μm, it becomes difficult to uniformly disperse the inorganic pigment in the sealing material, and there is a possibility that poor sealing occurs locally.

Since the alkali borosilicate glass has a low thermal expansion coefficient, it is not always necessary to add a refractory filler powder in order to match the thermal expansion coefficient of the material to be sealed. However, since bismuth-based glass has a high thermal expansion coefficient, in some cases, it is necessary to add a refractory filler powder in order to match the thermal expansion coefficient of the material to be sealed. The sealing material for organic EL displays of the present invention can contain up to 45% by mass of a refractory filler powder. If the refractory filler powder is added, the thermal expansion coefficient of the sealing material can be matched with the thermal expansion coefficient of the object to be sealed, and as a result, it is possible to prevent a situation in which undue stress remains in the sealing portion. it can. The refractory filler powder is composed of zircon, zirconia, tin oxide, aluminum titanate, β-spodumene, mullite, titania, quartz glass, β-quartz, willemite, zirconium phosphate compounds (for example, zirconium phosphate, zirconium tungstate phosphate). Etc.), zirconium tungstate and NZP type crystals (for example, NbZr (PO ₄ ) ₃ , [AB ₂ (MO ₄ ) ₃ ] crystalline structure,
A: Li, Na, K, Mg, Ca, Sr, Ba, Zn, Cu, Ni, Mn etc. B: Zr, Ti, Sn, Nb, Al, Sc, Y etc. M: P, Si, W, Mo etc. ) Or a solid solution thereof can be used. In addition to the above refractory filler powder, quartz glass, β-eucryptite, etc. may be added for adjustment of the thermal expansion coefficient of the sealing material, adjustment of fluidity and improvement of mechanical strength. it can.

In the sealing material for organic EL displays of the present invention, the average particle diameter D ₅₀ of the refractory filler powder is preferably less than 15 μm, more preferably 0.5 to 10 μm, and even more preferably 1 to ₅ μm. When the average particle diameter D ₅₀ of the refractory filler powder is 15 μm or more, the sealing portion is likely to be thick, the gap between the two glass substrates is increased, and the organic EL display is difficult to be thinned. If the average particle diameter D ₅₀ of the refractory filler powder is less than 15 μm, the gap between the two glass substrates can be reduced. In such a case, the difference in the thermal expansion coefficient between the glass substrate and the sealing material is large. However, cracks and the like hardly occur in the glass substrate and the sealing part. Incidentally, the refractory filler powder effects (e.g., effect of reducing the thermal expansion coefficient of the sealing material) in order to accurately enjoy is to the average particle diameter D ₅₀ of the refractory filler powder than 0.5μm Is preferred.

In the sealing material for organic EL displays of the present invention, the maximum particle size D _max of the refractory filler powder is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. If the maximum particle diameter D _max of the refractory filler powder is larger than 30 μm, a portion having a thickness of 30 μm or more is generated at the sealing portion, so that the gap between the two glass substrates becomes non-uniform and the organic EL display becomes thin. It becomes difficult to convert. If the average particle diameter _Dmax of the refractory filler powder is 30 μm or less, the gap between the two glass substrates can be reduced. In such a case, the difference in the thermal expansion coefficient between the glass substrate and the sealing material is large. However, cracks and the like hardly occur in the glass substrate and the sealing part.

  The sealing material for organic EL display of the present invention may further contain glass fiber, glass beads, silica beads, resin beads, etc. up to 10% by mass as spacers in order to make the thickness of the sealing part uniform. . Moreover, the sealing material for organic EL displays of the present invention may further contain up to 10% by mass of transition metal powders such as Cu, Fe, Mn, and Co in order to promote light absorption.

Currently, an active matrix driving in which an active element such as a TFT is arranged and driven in each pixel is employed as an organic EL display as a driving method. Therefore, a non-alkali glass (for example, an organic EL display glass substrate) OA-10) manufactured by Nippon Electric Glass Co., Ltd. is used. Since the thermal expansion coefficient of the alkali-free glass is usually 40 × 10 ⁻⁷ / ° C. or less, it is difficult to strictly match the thermal expansion coefficient of the sealing material with the thermal expansion coefficient of the alkali-free glass. However, it is important to make the thermal expansion coefficient of the sealing material for organic EL display as small as possible. Specifically, the thermal expansion coefficient of the sealing material for organic EL display is 85 × 10 ⁻⁷ / ° C. or less (preferably 80 × 10 ⁻⁷ / ° C. or less, more preferably 75 × 10 ⁻⁷ / ° C. or less). If it does in this way, the stress concerning a sealing part can be made small and the stress fracture of a sealing part can be prevented.

  In the sealing material for organic EL displays of the present invention, the softening point is preferably 600 ° C. or lower, more preferably 580 ° C. or lower, and further preferably 560 ° C. or lower. When the softening point is higher than 600 ° C., the glass tends not to soften even when irradiated with laser light. To increase the sealing strength between the glass substrates, it is necessary to increase the output of the laser light or the like. The lower limit of the softening point is not particularly limited, but it is preferable to set the softening point to 385 ° C. or higher in consideration of the thermal stability of the glass.

  The sealing material for organic EL displays of the present invention may be used as it is in powder form, but it is easy to handle if it is kneaded uniformly with a vehicle and processed into a paste. The vehicle mainly includes a solvent and a resin, and the resin is added for the purpose of adjusting the viscosity of the paste. Moreover, surfactant, a thickener, etc. can also be added as needed. The produced paste is applied to a glass substrate using an applicator such as a dispenser or a screen printer, and is subjected to a binder removal process.

  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 acid esters and nitrocellulose are preferable because they have good thermal decomposability.

  As the solvent, N, N′-dimethylformamide (DMF), α-terpineol, higher alcohol, γ-butyllactone (γ-BL), tetralin, 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, triethylene glycol Propylene glycol monobutyl ether, propylene carbonate, dimethyl sulfoxide (DMSO), N-me -2-pyrrolidone and the like can be used. In particular, α-terpineol is preferable because it is highly viscous and has good solubility in resins and the like.

  Hereinafter, the present invention will be described in detail based on examples.

Tables 1 to 5 show reference examples (sample Nos. 1 to 10), examples (samples No. 11 to 15) and comparative examples (sample Nos. 16 to 21) of the present invention.

Each sample described in Tables 1 to 5 was prepared as follows. First, a glass batch in which raw materials such as various oxides and carbonates were prepared so as to have the glass composition shown in the table was prepared, and this was put in a platinum crucible and melted at 1250 ° C. for 1 hour. Next, the molten glass was formed into a thin piece with a water-cooled roller. Finally, the glass flakes were pulverized with a ball mill and classified by air to obtain glass powders having an average particle diameter D ₅₀ of 2.5 μm and a maximum particle diameter D _max of 10 μm.

Inorganic pigments include (Fe, Mn) (Fe, Mn) ₂ O ₄ , (Zn, Fe) (Fe, Cr) ₂ O ₄ , Ti _n O _2n-1 , (Co, Ni) O.ZrSiO ₄ , Cr ₂ O ₃ , (Zn, Fe) Fe ₂ O ₄ , (Sn, Sb) O ₂ , (Fe, Mn) (Fe, Cr, Mn) O ₄ were used. Each inorganic pigment was prepared such that the average particle diameter D ₅₀ was 1 μm.

Cordierite and willemite were used as the refractory filler powder. Each refractory filler powder was prepared such that the average particle size D ₅₀ was 3 μm and the maximum particle size D _max was 10 μm.

  As shown in the table, glass powder, inorganic pigment and refractory filler powder were mixed and sample No. 1-21 were produced. Sample No. About 1-21, the thermal expansion coefficient, the glass transition point, the softening point, the fluidity, the sealing strength, and the devitrification state were evaluated.

  The thermal expansion coefficient was determined with a TMA apparatus. The measurement temperature range was 30 to 300 ° C.

  The glass transition point and softening point were measured with a DTA apparatus. The measurement was performed in the atmosphere at a temperature rising rate of 10 ° C./min, and the measurement was started from room temperature.

The fluidity was evaluated by pressing each sample to a thickness of 2 mm and irradiating each pressed body with a YAG laser (power density 8 kW / cm ² ) having a wavelength of 1060 nm. After irradiation with the YAG laser, the state in which the glass was melted was observed in-situ with a microscope, and the case where the glass was softened and deformed was evaluated as “◯”, and the case where the glass was not softened and deformed was evaluated as “x”.

The sealing strength was evaluated as follows. First, after each sample and vehicle (acrylic resin-containing α-terpineol) were uniformly kneaded with a three-roll mill and formed into a paste, an alkali-free glass substrate (OA-10, Nippon Electric Glass Co., Ltd., □ 100 mm × 0) 0.5 mm thickness) was applied in a linear shape (30 μm thickness) and dried in a drying oven at 150 ° C. for 10 minutes. Next, the temperature was raised from room temperature at 10 ° C./min, and the glass substrate was baked at the softening point of each glass powder for 20 minutes, and then cooled to room temperature at 10 ° C./min, and glazed. Next, after another non-alkali glass substrate (OA-10 manufactured by Nippon Electric Glass Co., Ltd., □ 100 mm × 0.5 mm thickness) is accurately stacked on the non-alkali glass substrate on which the fired film is formed. The YAG laser (power density 8 kW / cm ² ) having a wavelength of 1060 nm was irradiated along the dry film to seal both glass substrates. Both glass substrates after sealing were dropped onto the concrete from 1 m above, and “◯” was evaluated when the sealing part was not peeled off from both glass substrates, and “X” was given when the sealing part was peeled off.

  In the devitrification state, the surface of the sealed portion formed by the above-described evaluation of the sealing strength is observed with an optical microscope (100 times), “○” indicates that no crystal is observed on the surface, and the crystal is observed on the surface. What was done was evaluated as "x".

  As is apparent from Tables 1 to 3, sample No. Nos. 1 to 15 have good evaluation of fluidity, sealing strength and devitrification state, and can be judged to be suitable for sealing materials for organic EL displays.

  As is apparent from Table 4, sample No. Since 16 and 17 did not contain an inorganic pigment, the evaluation of fluidity and sealing strength was poor. Sample No. No. 18 was poor in evaluation of sealing strength and devitrification state because of a large content of inorganic pigment.

  As is apparent from Table 5, sample No. Since 19 and 20 did not contain an inorganic pigment, the evaluation of fluidity and sealing strength was poor. Sample No. No. 18 was poor in evaluation of fluidity, sealing strength and devitrification state because the content of glass powder was small.

It is a schematic diagram which shows the softening point of glass when it measures with a macro type | mold DTA apparatus.

Claims (8)

A sealing material for organic EL display that is subjected to sealing treatment with laser light,
The glass powder 50 to 99.9 wt%, an inorganic pigment containing 0.1 to 20 mass%, glass powder, as a glass composition, in _{mole%, Bi 2 O 3 5~50%} , B 2 O 3 10 -50%, ZnO 5-55% ,
Sealing material for an organic EL display, wherein the average particle diameter _{D 50} of the inorganic pigment is 0.01 to 5 [mu] m. Inorganic pigments, composite _{oxide, C, Co 3 O 4,} CuO, Cr 2 O 3, Fe 2 O 3 ( including _{FeO), MnO 2, SnO,} NiO, Ti n O 2n-1 (n is an integer) The organic EL display sealing material according to claim 1, wherein the organic EL display sealing material is one or more selected from the group consisting of:   Inorganic pigments include Al-Co composite oxide, Al-Co-Cr composite oxide, Al-Cr-Fe-Zn composite oxide, Al-Co-Li-Ti composite oxide, Al-Cu-. Fe-Mn complex oxide, Al-Fe-Mn complex oxide, Al-Si complex oxide, Ba-Ni-Ti complex oxide, Ca-Cr-Si-Sn complex oxide, Co- Cr composite oxide, Co-Cr-Fe-Mn composite oxide, Co-Cr-Fe-Ni composite oxide, Co-Cr-Fe-Ni-Si-Zr composite oxide, Co-Cr- Fe composite oxide, Co-Cr-Fe-Mn composite oxide, Co-Cr-Fe-Ni-Zn composite oxide, Co-Fe composite oxide, Co-Fe-Mn-Ni composite oxide , Co-Li-P composite oxide, Co-Ni-Si-Zr composite oxide Co-Ni-Nb-Ti complex oxide, Co-Ni-Sb-Ti complex oxide, Co-Ni-Ti-Zn complex oxide, Co-Si complex oxide, Co-Si-Zn -Based composite oxide, Co-Ti-based composite oxide, Cr-Cu-based composite oxide, Cr-Cu-Mn-based composite oxide, Cr-Fe-based composite oxide, Cr-Fe-Mn-based composite oxide, Cr -Fe-Zn complex oxide, Cr-Nb-Ti complex oxide, Cr-Sb-Ti complex oxide, Fe-Cr complex oxide, Fe-Mn complex oxide, Fe-Ti complex Oxides, Fe-Ti-W complex oxides, Fe-Ti-Zn complex oxides, Fe-Zn complex oxides, Ni-Nb-Ti complex oxides, Ni-Sb-Ti complex oxides One selected from Ni-Ti-W composite oxide and Sb-Sn composite oxide The organic EL sealing material for display according to claim 1 or 2, wherein the or at two or more. The organic EL sealing material for display according to claim 1, wherein the average particle diameter _{D 50} of the inorganic pigment is 0.01 to 3.5 [mu] m.   Furthermore, the sealing material for organic EL displays in any one of Claims 1-4 characterized by including a refractory filler powder. The thermal expansion coefficient is 85 × 10 ⁻⁷ / ° C. or less, The sealing material for organic EL displays according to claim 1.   The sealing material for organic EL displays according to any one of claims 1 to 6, wherein the softening point is 600 ° C or lower. 6. The sealing material for organic EL displays according to claim 5, wherein the maximum particle diameter _Dmax of the refractory filler powder is 20 [ _mu] m or less.

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