JP2005015280A - Lead-free low melting glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that an answer to solve a new problem that cavities occur in electronic material substrates is not found, and the new problem is becoming a large factor inhibiting the development of industry. <P>SOLUTION: A B<SB>2</SB>O<SB>3</SB>-ZnO-BaO-based lead-free low melting glass is transparent and insulative, and contains Sn in an amount of 0.1-10 wt.% expressed in terms of its oxide. The B<SB>2</SB>O<SB>3</SB>-ZnO-BaO-based lead-free low melting glass contains, by weight, 0-8% SiO<SB>2</SB>, 18-32% B<SB>2</SB>O<SB>3</SB>, 20-50% ZnO, 15-50% BaO, and 0-15% RO(MgO, CaO and SrO), with the proviso that the weight ratio of BaO to (BaO + RO) is ≥0.7 and ≤0.95 and the weight ratio of B<SB>2</SB>O<SB>3</SB>to ZnO is ≥0.5 and ≤1.3, and is characterized in that the coefficient of thermal expansion in a range of 30-300°C is (65-95)×10<SP>-7</SP>/°C and the softening point is ≥550 and ≤630°C. Further, a substrate for an electronic material and a panel for a PDP, using the lead-free low melting glass, are also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４７】
【表２】

【００４８】
【発明の効果】
本発明により、ＰＤＰに代表される電子材料基板の電極周辺に発生する空洞を抑制することができた。
【図面の簡単な説明】
【図１】本発明の低融点ガラスの使用部位を一例として示すプラズマディスプレイパネルの概略図である。
【符号の説明】
１ 前面ガラス板
２ 背面ガラス板
３ 封止材
４ 透明電極
５ バス電極
６ 透明誘電体
７ 保護膜
８ アドレス電極
９ 白色誘電体
１０ 蛍光体
１１ 隔壁
１２ 紫外線
１３ 可視光[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an insulating coating material for an electronic material substrate typified by a plasma display panel, a liquid crystal display panel, an electroluminescence panel, a fluorescent display panel, an electrochromic display panel, a light emitting diode display panel, a gas discharge display panel, and the like. The present invention relates to a low melting point glass used as a sealing material.
[0002]
[Prior art]
With the recent development of electronic components, many types of display panels such as plasma display panels, liquid crystal display panels, electroluminescence panels, fluorescent display panels, electrochromic display panels, light emitting diode display panels, and gas discharge display panels have been developed. Has been. Among them, a plasma display panel (hereinafter abbreviated as PDP) is attracting attention as a thin and large flat color display device. In a PDP, a large number of cells are provided between a front substrate and a rear substrate used as a display surface, and an image is formed by performing plasma discharge in the cells. This cell is partitioned by partition walls, and an electrode is formed for each pixel unit in order to control the display state of each pixel forming an image.
[0003]
As shown in FIG. 1, the PDP panel is sandwiched between a front glass plate 1 and a back glass plate 2, and the front glass plate 1 and the back glass plate 2 are sealed with a sealing material 3. There are a front glass plate 1, a transparent electrode 4, a bus electrode 5, a transparent dielectric 6 and a protective film at the front of the panel, and a back glass plate 2, an address electrode 8, a white dielectric 9, and a phosphor 10 on the back. There is a partition wall 11. Generally, the ultraviolet rays 12 become visible light 13 due to the action of the phosphor 10.
[0004]
For example, a transparent electrode (ITO or the like), a bus, and an address electrode (Cr-Cu-Cr; sometimes replaced with Al instead of Cu) are disposed as conductors on the front or back substrate of the PDP. A dielectric layer is formed so as to cover them, and a gas is sealed between the front and back substrates on which the dielectric layer is formed to form a panel structure. By the way, low melting point glass is used for the dielectric as described above, and when forming a structure, a low melting point glass paste is applied on a substrate on which electrodes are arranged and fired to form a dielectric film. To do.
[0005]
Conventionally, lead glass has been employed for low melting glass, for example, low melting glass for coating a substrate. Although the lead component is an important component for making the glass have a low melting point, it has a great detrimental effect on the human body and the environment, and has recently tended to be avoided. However, when the lead-based glass is changed to a lead-free low-melting glass, a cavity is generated at the interface between the formed dielectric film and the copper electrode, resulting in a problem that the sealed gas leaks after the panel is formed.
[0006]
The present inventor has disclosed a SiO ₂ —B ₂ O ₃ —BaO—ZnO-based low-melting glass having a transparent and electrically insulating property for covering a substrate surface directly or covering a conductor and a semiconductor pattern disposed on the substrate. A low-melting glass having a thermal expansion coefficient at 30 ° C. to 300 ° C. of 65 to 95 × 10 ⁻⁷ / ° C., a softening point of 600 ° C. or less, and a dielectric constant of 7.5 or less at room temperature and 1 MHz, particularly A low melting glass for forming a film on a transparent electrode line pattern arranged on a display panel substrate is disclosed (see Patent Document 1).
[0007]
Further, for example, a plasma display material in which the contents of PbO and CuO are limited (see, for example, Patent Document 2), and a plasma display in which the contents of BaO + SrO + MgO in addition to PbO, B ₂ O ₃ , SiO ₂ , and CaO are also limited. Materials for use (see, for example, Patent Document 3) are disclosed.
[0008]
[Patent Document 1]
JP 2002-12445 A [Patent Document 2]
JP 2001-52621 A [Patent Document 3]
Japanese Patent Laid-Open No. 2001-80934
[Problems to be solved by the invention]
In electronic materials such as PDP, lead-free is being studied due to environmental problems, and on the other hand, more strict manufacturing conditions and quality are required. For this reason, what has not been a problem in the past is also highlighted and may be taken up as a major problem. For example, there is a problem of a cavity generated beside an electrode used in a PDP, that is, a cavity generated in a portion where a low melting point glass and a conductor portion of a metal electrode are in contact with each other. This is a new problem that has become apparent in recent years and has not been seen in the past. Therefore, until now, almost no awareness was given, and the occurrence of such problems was not recognized. It is unclear what manufacturing conditions are affecting the cavity problem, and of course the countermeasures are not known. Factors that hinder industrial development as a major problem in electronic materials such as recent PDPs. It is becoming.
[0010]
Even in the disclosed literature, this void problem is not described, and an effective countermeasure is unknown. That is, the method disclosed in Japanese Patent Application Laid-Open No. 2002-12445 has an advantage that not only the influence on the human body and the environment is reduced and the electrical insulation is excellent, but also the adverse effects due to alkali leaching can be eliminated. Japanese Patent Laid-Open No. 2001-52621 and Japanese Patent Laid-Open No. 2001-80934 are remarkably improved with respect to yellowing, but are not effective for countermeasures against cavities that are a problem in the present invention. There is also a basic problem of containing lead.
[0011]
[Means for Solving the Problems]
The present invention is a B ₂ O ₃ —ZnO—BaO-based lead-free low-melting glass characterized by containing 0.1 to 10% by weight of Sn converted to an oxide in a transparent insulating lead-free low-melting glass.
[0012]
In addition, the above lead-free containing 0 to 8 SiO ₂ , 18 to 32 B ₂ O ₃ , 20 to 50 ZnO, 15 to 50 BaO, and 0 to 15 RO (MgO, CaO and SrO) by weight%. It is a low melting glass.
[0013]
Moreover, it is said lead-free low melting glass whose weight ratio of BaO / (BaO + RO) is 0.7-0.95.
[0014]
_The weight ratio of B ₂ O 3 / ZnO is above lead-free low-melting-point glass is 0.5 to 1.3.
[0015]
Moreover, it is said lead-free low melting glass whose thermal expansion coefficient in 30 degreeC-300 degreeC is (65-95) x10 < ^-7 > / degreeC, and a softening point is 550 degreeC or more and 630 degrees C or less.
[0016]
Furthermore, it is an electronic material substrate using the above lead-free low-melting glass.
[0017]
Still further, the present invention is a PDP panel using the above lead-free low melting point glass.
[0018]
As described above, by adding an oxide containing Sn to the lead-free low-melting glass of the present invention in the above-mentioned range, a low-melting point made into a paste form on a glass substrate for a PDP panel in which transparent electrode wires and bus electrode wires are arranged. After the glass is applied and baked to form the low melting point glass layer, the problem that cavities are generated around the electrode can be solved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a B ₂ O ₃ —ZnO—BaO-based lead-free low-melting glass characterized by containing 0.1 to 10% by weight of Sn converted to an oxide in a transparent insulating lead-free low-melting glass. The inclusion of Sn is extremely effective for the cavity problem occurring beside an electrode used in an electronic material substrate, for example, a PDP. If Sn converted to oxide is less than 0.1% by weight, the effect is not obtained. On the other hand, if it exceeds 10% by weight, the glass becomes unstable and reaction bubbles with the electrode may be generated. Preferably it is 0.1 to 5 weight%, More preferably, it is 0.1 to 3 weight%. B ₂ O ₃ —ZnO—BaO-based lead-free low-melting glass has many features such as transparency, chemical resistance, and electrical insulation, and can be used for electronic material substrates such as PDPs.
[0020]
Further, the SiO _{2 0~8,} B _{2 O 3} and 18 to 32, ZnO and 20 to 50, BaO 15 to 50, and RO (MgO, CaO and SrO) and containing 0 to 15 lead-free low-melting-point in weight% It is glass.
[0021]
SiO ₂ is a glass-forming component. By coexisting with B ₂ O ₃ which is another glass-forming component, a stable glass can be formed even in a small amount, and it is 8% or less (% by weight) in the glass. The same applies to the following). If it exceeds 10%, the softening point of the glass will increase, making the formability and workability difficult.
[0022]
For example, in the production of a PDP, an insulating film is once formed on the electrode line pattern, and then the insulating film coated on the part is dissolved and removed with an acid so as to form an electrode line extraction part on the peripheral edge of the panel. However, if the amount is too large, the acid resistance increases more than necessary, and dissolution becomes difficult. Further, in order to make the glass more stable, the content is more preferably 2% or more. Al ₂ O ₃ can be substituted and introduced within a range of 1/2 weight or less of SiO ₂ and 1% or less in the glass.
[0023]
B ₂ O ₃ is a glass forming component SiO ₂ Similarly, the glass melt is facilitated, suppresses an excessive increase in the thermal expansion coefficient of the glass, and, given an appropriate fluidity to the glass upon baking, the glass with SiO ₂ It decreases the dielectric constant. It is good to make it contain in 18 to 32% of range in glass. If it is less than 18%, the glass becomes unstable and devitrification tends to occur. On the other hand, if it exceeds 32%, the softening point of the glass increases. More preferably, it is 22 to 30% of range.
[0024]
ZnO lowers the softening point of glass, imparts moderate fluidity, and adjusts the thermal expansion coefficient to an appropriate range, and is contained in the glass in a range of 20 to 50%. If it is less than 20%, the above effect cannot be exhibited, and if it exceeds 50%, the glass becomes unstable and devitrification tends to occur. More preferably, it is 34 to 45% of range.
[0025]
BaO, like ZnO, lowers the softening point of glass, imparts moderate fluidity, and adjusts the thermal expansion coefficient to an appropriate range, and is contained in the range of 15 to 50%. If it is less than 15%, the above-mentioned action cannot be exhibited. On the other hand, if it exceeds 50%, the thermal expansion coefficient is excessively increased.
[0026]
In addition, RO (MgO, CaO and SrO), which is the same divalent metal oxide as BaO, imparts fluidity to the glass and adjusts the thermal expansion coefficient to an appropriate range. At least one kind of RO is appropriately selected from MgO, CaO, and SrO, and the total content of RO is 0 to 15%. If it exceeds 15%, crystallization tends to occur. Preferably, it is 1 to 10% of range.
[0027]
The lead-free low-melting glass described above, wherein the weight ratio of BaO / (BaO + RO) is 0.7 or more and 0.95 or less. If it is less than 0.7, the devitrification tendency tends to increase, or the softening point may increase or the thermal expansion coefficient may fall outside the appropriate range. On the other hand, if it exceeds 0.95, it becomes difficult to improve the stability and adjust the thermal expansion coefficient. Preferably, it is the range of 0.8-0.9.
[0028]
It is also important that the weight ratio of B ₂ O ₃ / ZnO is 0.5 or more and 1.3 or less. If the amount is less than 0.5%, the problem of easy crystallization occurs. If the value exceeds 1.3, the softening point becomes too high. Preferably, it is the range of 0.7-1.
[0029]
In addition, since PbO is not included substantially, the influence which has on a human body and an environment can be made completely. Here, “substantially free of PbO” means an amount of PbO mixed as an impurity in the glass raw material. For example, if it is in the range of 0.3 wt% or less in the low-melting glass, there is almost no influence on the adverse effects described above, that is, the influence on the human body and the environment, the insulation characteristics, etc., and it is substantially not affected by PbO. Become.
[0030]
Furthermore, if the problem of insulation is small, Na ₂ O can be introduced. In general, the amount is within 5% by weight, but is not limited to this depending on the place of use or application.
[0031]
It is a lead-free low-melting glass having a thermal expansion coefficient of (65 to 95) × 10 ⁻⁷ / ° C. at 30 ° C. to 300 ° C. and a softening point of 550 ° C. or more and 630 ° C. or less. When the thermal expansion coefficient is outside (65 to 95) × 10 ⁻⁷ / ° C., problems such as peeling of the film and warping of the substrate occur when a thick film is formed on the electronic material substrate. Preferably, it is in the range of (75 to 85) × 10 ⁻⁷ / ° C. If the softening point exceeds 630 ° C., problems such as softening deformation of the substrate occur. If it is less than 550 ° C., a problem may occur when it is used as an electronic material substrate. Preferably, they are 560 degreeC or more and 610 degrees C or less, More preferably, they are 565 degreeC or more and 600 degrees C or less.
[0032]
Furthermore, it is a substrate for electronic materials using the low melting point glass. By using the above-described low-melting glass, a substrate for an electronic material without a cavity can be obtained.
[0033]
Furthermore, the present invention is a PDP panel using the above-mentioned low melting point glass. By using the above-described low melting point glass, a PDP panel without a cavity can be obtained.
[0034]
When lead-free low-melting glass is used for sealing and coating, it is used in powder form. This powdered glass is usually mixed with a low expansion ceramic filler, a heat-resistant pigment or the like, if necessary, and then kneaded with an organic oil to form a paste.
[0035]
As the glass substrate, a transparent glass substrate, particularly soda lime silica glass, glass similar to the glass (high strain point glass), or alumino lime borosilicate glass with little (or almost no alkali content) is used. Has been.
[0036]
【Example】
Hereinafter, a description will be given based on examples.
(Front glass substrate for PDP)
The front glass substrate is made of clear soda-lime glass or glass having a similar composition, thermophysical properties, and the like. A patterned transparent electrode wire, for example, an indium oxide-tin (ITO) -based or tin oxide (SnO ₂ ) -based electrode wire is applied to the surface (one surface) of the front glass substrate by a sputtering method or a CVD method.
[0037]
Further, a part of the transparent electrode line is covered, and chromium-copper-chromium (Cr-Cu-Cr) [or aluminum is used instead of copper] is formed as the bus electrode line. A transparent insulating coating (hereinafter referred to as insulating coating) made of the low melting point glass according to the present invention is applied to the upper layer. Insulating coating is a pre-manufactured and sized mixture of low melting point glass powder and paste oil applied on the front substrate and transparent electrode wire by screen printing, etc., and baked at 630 ° C. or less to form a thick film with a thickness of about 30 μm. To do. The thickness of about 30 μm is necessary and sufficient for exhibiting display performance by gas discharge and long-term stability.
[0038]
Further, the production of the front glass substrate for PDP is completed by covering the insulating coating and coating the protective magnesia layer by sputtering or the like.
Below, the Example which employ | adopted the low melting glass of this invention as insulating coating is shown.
[0039]
(Production of low melting point glass mixed paste)
Fine silica sand as SiO ₂ source, boric acid as B ₂ O ₃ source, zinc white as ZnO source, barium carbonate as BaO source, magnesium carbonate as MgO source, calcium carbonate as CaO source, strontium carbonate as SrO source And sodium carbonate as the Na ₂ O source and tin oxide as the SnO ₂ source. Furthermore, red lead was used as the PbO source, orthophosphoric acid was used as the P ₂ O ₅ source, and indium oxide was used as the In ₂ O ₃ source. After preparing these as a desired low melting glass composition, it puts into a platinum crucible, heat-melts in 1000-1200 degreeC and 1-2 hours in an electric heating furnace, Examples 1-5 of Table 1, Table 1 The glass of the composition shown in 2 comparative examples 1-5 was obtained.
[0040]
A part of the glass was poured into a mold, made into a block shape, and used for measurement of thermal properties (thermal expansion coefficient, softening point). The remaining glass was flaked with a rapid cooling twin roll molding machine and sized with a pulverizer into a powder having an average particle size of 2 to 4 μm and a maximum particle size of less than 15 μm.
[0041]
Next, paste oil composed of α-terpineol and butyl carbitol acetate was mixed with ethyl cellulose as a binder and the above glass powder to prepare a paste suitable for screen printing having a viscosity of about 300 ± 50 poise.
[0042]
(Formation of insulating coating)
An ITO pattern film is formed on a soda-lime-based glass substrate having a thickness of 2 to 3 mm and a size of 150 mm □ by a sputtering method. The paste was applied by screen printing.
Next, after drying, baking was performed at 630 ° C. or lower for 40 minutes to form an insulating coating.
The obtained sample was subjected to the following test.
[0043]
(Cavity observation around the electrode)
After firing the thick film on a 30 × 30 mm size glass substrate, the fractured surface was observed with a microscope.
(Reaction with bus electrode)
After firing a thick film on a 30 × 30 mm size glass substrate, ○ indicates that there is no bubble of 30 μm or more around the bus electrode, and x indicates that there is no bubble around the bus electrode.
[0044]
(result)
The low melting point glass composition and various test results are shown in the table.
As shown in Examples 1 to 5 in Table 1, within the composition range of the present invention, the generation of cavities around the copper electrode is suppressed, the reaction with the bus electrode is also suppressed, etc. It is suitable as a low-melting glass for forming a transparent insulating coating, particularly as a low-melting glass for a PDP full-surface glass substrate.
[0045]
On the other hand, Comparative Examples 1 to 5 in Table 2 outside the composition range of the present invention do not show preferable physical properties and preferable characteristics as a low-melting glass for coating a substrate such as PDP, but as a low-melting glass for coating a substrate such as PDP. Not applicable.
[0046]
[Table 1]

[0047]
[Table 2]

[0048]
【The invention's effect】
According to the present invention, cavities generated around the electrodes of an electronic material substrate typified by PDP can be suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic view of a plasma display panel showing, as an example, a portion where a low melting point glass of the present invention is used.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Front glass plate 2 Back glass plate 3 Sealing material 4 Transparent electrode 5 Bus electrode 6 Transparent dielectric 7 Protective film 8 Address electrode 9 White dielectric 10 Phosphor 11 Partition 12 Ultraviolet ray 13 Visible light

Claims (7)

The transparent insulating lead-free low-melting-point glass, Sn in terms of oxide, characterized in that it comprises 0.1 to 10 wt% _B 2 _O 3 -ZnO-BaO-based lead-free low-melting-point glass. It contains 0 to 8 SiO ₂ , 18 to 32 B ₂ O ₃ , 20 to 50 ZnO, 15 to 50 BaO, and 0 to 15 RO (MgO, CaO and SrO) by weight%. The lead-free low melting point glass according to claim 1. The lead-free low-melting glass according to claim 1 or 2, wherein a weight ratio of BaO / (BaO + RO) is 0.7 or more and 0.95 or less. The lead-free low-melting glass according to any one of claims 1 to 3, wherein a weight ratio of B ₂ O ₃ / ZnO is 0.5 or more and 1.3 or less. The lead-free lead according to any one of claims 1 to 4, wherein the coefficient of thermal expansion at 30 to 300 ° C is (65 to 95) × 10 ^-7 / ° C, and the softening point is 550 to 630 ° C. Low melting glass. 6. A substrate for electronic materials, wherein the lead-free low-melting glass according to claim 1 is used. 6. A PDP panel using the lead-free low-melting glass according to claim 1.

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