JP4239421B2 - Surge absorber manufacturing method and surge absorber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surge absorber manufacturing method and surge absorber used for protecting various devices from surges and preventing accidents.
[0002]
[Prior art]
Abnormal voltage is applied to parts where electronic devices for communication equipment such as telephones, facsimiles, modems, etc. are connected to communication lines, or parts that are susceptible to electric shock due to abnormal voltage (surge voltage) such as lightning surge or static electricity, such as CRT drive circuits. In order to prevent the electronic device and the printed circuit board on which this device is mounted from being damaged due to thermal damage or ignition, a surge absorber is connected.
[0003]
As an example of such a surge absorber, the one shown in FIG. 4 is known. As shown in FIG. 4, the surge absorber 1 has cap electrodes 5 and 5 at both ends of an absorber element in which a conductive film 3 having a discharge gap 4 (microgap) is formed on the peripheral surface of a cylindrical ceramic member 2. The covered glass is accommodated in a cylindrical glass tube 7 together with an inert gas, and a pair of sealing electrodes 6 and 6 face each other at both ends of the cylindrical glass tube 7 and are sealed by high-temperature heating. It is a sealed type.
[0004]
[Problems to be solved by the invention]
However, the conventional surge absorber 1 as described above absorbs only the surge of the circuit electrically connected by the two lead wires 6A and 6A connected to the sealing electrodes 6 and 6, respectively. We were unable to cope with surges such as static electricity entering from the space.
Moreover, such a glass tube sealed surge absorber 1 is manufactured by enclosing the absorber element and inert gas in the glass tube 7, so that the product shape is cylindrical and is not suitable for surface mounting. Further, in the case where the absorber element is sealed in the glass tube 7 as described above, the size becomes relatively large, and it has been difficult to meet the demand for downsizing that has been increasing in recent years.
[0005]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a surge absorber manufacturing method and surge absorber that can absorb surges such as static electricity entering from a space, can be surface-mounted, and can be downsized. And
[0006]
[Means for Solving the Problems]
In order to solve the above problems and achieve such an object, the present invention forms a pair of discharge electrodes opposed to each other so that a discharge gap is defined on the upper surface of the insulating substrate, A lid joining process for joining the peripheral edge of the lid to the upper surface of the insulating substrate so as to surround the space above the discharge gap , and an inert gas is enclosed in the internal space formed by the lid A method of manufacturing a surge absorber having a gas sealing step, wherein the lid joining step is performed by using a conductive material containing a metal powder and an inorganic binder , with one discharge electrode and a tip portion of the insulating substrate. A step of forming the base end portion in a groove provided on the upper surface of the insulating substrate, and a step of forming the other discharge electrode on the upper surface of the insulating substrate ; Before inorganic material The bonding material, at least one is applied to one of the peripheral edge or the other of the discharge electrodes of the metal of the lid, and placing the lid on the upper surface of the insulating substrate, the lid, the Bonding a part of the peripheral edge so as to be positioned above the groove and providing a gap between the one discharge electrode and the peripheral edge of the lid; and heating the peripheral edge of the lid by extinguishing the bonding material is taken up in the discharge electrode of the other reacted melt the inorganic binder Te, organic and the step of electrically bonding the periphery of the lid and the other discharge electrode The gas sealing step includes applying an insulating paste capable of venting the inside and outside of the gap, and heating and melting the insulating paste in the gap in an inert gas atmosphere so that the gap is hermetically sealed. And clogging to a state .
[0007]
In the surge absorber manufactured by such a manufacturing method, a metal lid is electrically joined to the other discharge electrode, so that surges such as static electricity entering the metal lid from the space are collected. It can be used as an electrode to be electrified, so that it is possible to absorb static electricity entering from a gap such as a device case or a SW pad or to escape to the ground. Furthermore, discharge can be performed between one discharge electrode and a metal lid that is not electrically joined to the one discharge electrode, and the thermal effect on the discharge electrode can be reduced.
Further, since the lid forming the discharge space (internal space formed by the lid) is made of metal, the lid can be manufactured at low cost. In addition, by using an insulating substrate, the whole becomes a chip shape, and miniaturization and surface mounting can be achieved.
[0008]
Also, just forming the groove on the upper surface of the insulation substrate, easily with to form a gap between the peripheral portion and one of the discharge electrodes of the lid, the closure operations of the gap, in the grooves insulating material paste It can be easily done by embedding.
[0009]
The surge absorber manufacturing method according to the present invention is characterized in that the bonding material is melted simultaneously with heating in the step of closing the gap in the gas sealing step.
When such a manufacturing method is used, the periphery of the lid is bonded to the upper surface of the insulating substrate, the gap formed by the periphery of the lid and one of the discharge electrodes is closed, and the inert gas is sealed. Can be performed simultaneously, and the manufacturing process of the surge absorber can be reduced and the manufacturing efficiency can be improved.
[0010]
The inorganic binder is composed of glass fine particles mainly composed of one or more oxides of SiO ₂ , B ₂ O ₃ , Na ₂ O, PbO, ZnO, or BaO, and the bonding The material is SiO ₂ or 50 wt% or more of SiO ₂ and the balance is one or more oxides of Al ₂ O ₃ , MgO, ZrO ₂ or TiO ₂ , or SiO ₂ , B ₂ O ₃ , It is preferable that the glass is mainly composed of one or more oxides of Na ₂ O, PbO, ZnO or BaO.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a perspective view of a surge absorber according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the surge absorber in FIG.
[0012]
As shown in FIGS. 1 and 2, the surge absorber 10 according to the present embodiment has a substantially rectangular chip shape, and a metal powder is applied to the upper surface 11A of an insulating substrate 11 made of an insulating material such as alumina, for example. A pair of discharge electrodes 12 and 13 made of a conductive material including an inorganic binder is formed so as to face each other, and between the tip of one discharge electrode 13 and the tip of the other discharge electrode 12. A discharge gap 14 (microgap) is formed with a predetermined dimension.
[0013]
Here, although the discharge electrodes 12 and 13 are comprised from the electroconductive material containing a metal powder and an inorganic binder, this metal powder is noble metals, such as Ag, Au, Pd, and Pt, or Examples of the inorganic binder include SiO ₂ , B ₂ O ₃ , Na ₂ O, and PbO. , ZnO or BaO, and fine particles of glass such as borosilicate glass, zinc borate glass, cadmium borate glass, lead zinc silicate glass, etc., mainly composed of one or more oxides of ZnO or BaO. It is done.
[0014]
Further, on the upper surface 11A of the insulating substrate 11, the discharge electrodes 12 and 13 are formed so that the respective base end portions 12A and 13A reach the respective opposing end surfaces 11B and 11B of the insulating substrate 11. The upper surface 11A of the insulating substrate 11 is provided with a groove portion 11C in a portion where one discharge electrode 13 is formed. In the one discharge electrode 13, from the middle portion to the base end portion 13A. A slope approaching the lower surface of the insulating substrate 11 is provided along the groove portion 11C toward the base end portion 13A. That is, one discharge electrode 13 is provided in the groove portion 11 </ b> C from the middle portion to the base end portion 13 </ b> A, and only the distal end portion is positioned on the upper surface 11 </ b> A of the insulating substrate 11.
[0015]
Then, the upper surface 11A of the insulating substrate 11 on which the discharge electrodes 12 and 13 are formed is covered with a cover so as to surround the space above the discharge electrodes 12 and 13 and the discharge gap 14, as shown in FIGS. The peripheral portion 15A of the body 15 is joined by a joining material. The lid body 15 is made of a bottomed annular metal such as Kovar having a flange-shaped peripheral edge portion 15 </ b> A whose diameter is increased by one step in the radial direction.
[0016]
Here, the bonding material used for bonding the lid 15 and the insulating substrate 11 is, for example, SiO ₂ or 50% by weight or more of SiO ₂ with the balance being Al ₂ O ₃ , MgO, ZrO ₂ or TiO _2. Insulating inorganic substances made of a paste made of one or more oxides of these, or oxidation of one or more of SiO ₂ , B ₂ O ₃ , Na ₂ O, PbO, ZnO or BaO An insulating inorganic material made of a glass paste containing a material as a main component is applied in a thin film having a thickness of about 0.1 to 10 μm.
[0017]
Further, such a bonding material joins the peripheral portion 15A of the lid 15 and the upper surface 11A of the insulating substrate 11 when heated and melted, but is applied to the upper surface of the other discharge electrode 12. The material reacts and melts with the inorganic binder, which is a component contained in the discharge electrode 12, so that the other discharge electrode 12 absorbs and disappears, and the other discharge electrode 12 and the peripheral portion 15A of the lid body 15 are lost. Electrically joined and conducted.
At this time, one of the discharge electrodes 13 is inclined so as to approach the lower surface of the insulating substrate 11 from the middle portion toward the base end portion 13A, so that the lid positioned above the groove portion 11C. A predetermined gap 16 is formed without contacting the peripheral edge 15 </ b> A of the body 15.
[0018]
A gap 16 formed between the one discharge electrode 13 and the peripheral edge 15A of the metal lid 15 is sealed with an insulating material 17 such as glass. Further, in the internal space formed by the lid 15, for example, He, Ar, Ne, Xe, SF ₆ , CO ₂ , C ₃ F ₈ , C ₂ F ₆ , CF ₄ , H ₂ and a mixed gas thereof are used. An inert gas suitable for discharge, etc., is enclosed, and this internal space is made a discharge space.
[0019]
Then, the terminal electrodes 18 in which the base end portions 12A and 13A of the discharge electrodes 12 and 13 formed so as to reach the both end faces 11B and 11B of the insulating substrate 11 are joined to the both end faces 11B and 11B of the insulating substrate 11. , 18 to form a surge absorber 10 having a chip shape.
[0020]
In the surge absorber 10 configured as described above, a surge from a circuit or the like connected to the terminal electrodes 18 and 18 by the discharge gap 14 formed by the pair of discharge electrodes 12 and 13 facing each other. In addition, the metal lid 15 electrically joined to the other discharge electrode 12 can be used as an electrode for absorbing surges such as static electricity entering from the space. Surges such as static electricity entering from gaps such as cases and SW pads can be absorbed or released to the ground. Moreover, a discharge can be performed between one discharge electrode 13 and the metal lid 15 that is not electrically joined to the one discharge electrode 13, and there is a thermal effect on the discharge electrodes 12 and 13. The life of the surge absorber can be extended.
[0021]
Further, since the lid 15 forming the discharge space is made of metal, the lid 15 can be manufactured at low cost, and the manufacturing cost of the surge absorber 10 can be reduced. Furthermore, by configuring the surge absorber 10 using the insulating substrate 11, the chip-shaped surge absorber 10 can be obtained, and the miniaturization and surface mounting thereof can be achieved.
Further, when changing the size of the discharge space, it is only necessary to change the size of the lid 15 alone, and the size of the discharge space can be easily changed.
[0022]
Moreover, one discharge electrode 13 is provided in the groove portion 11C formed on the upper surface 11A of the insulating substrate 11 from the middle portion to the base end portion 13A, and a part of the peripheral edge portion 15A of the lid body 15 is a groove portion. Since the gap 16 is formed so as to be positioned above 11C, the peripheral portion 15A of the lid 15 and one of the discharge electrodes can be easily formed simply by forming the groove 11C on the upper surface 11A of the insulating substrate 11. The gap 16 can be formed between the groove 13 and the gap 16 can be closed easily by embedding the insulating material 17 in the groove 11C.
[0023]
Hereinafter, a method of manufacturing the surge absorber 10 having the above configuration will be described. First, as shown in FIG. 1, an insulation having a groove portion 11 </ b> C for inclining one discharge electrode 13 so as to approach the lower surface of the insulating substrate 11 from the middle portion toward the base end portion 13 </ b> A side. The discharge electrodes 12 and 13 facing each other are formed on the upper surface 11A of the conductive substrate 11.
[0024]
The discharge electrodes 12 and 13 are formed in the direction along the groove 11C by using a conductive material including the metal powder and the inorganic binder as described above by sputtering, vapor deposition, ion plating, printing, baking, or the like. After forming into a single strip-shaped thin film, the cut portion becomes the discharge gap 14 by irradiating the laser beam to the middle position of the strip-shaped thin film, that is, the position where the discharge gap 14 is to be formed. The discharge electrodes 12 and 13 facing each other are formed.
[0025]
Next, on the upper surface 11A of the insulating substrate 11, a bonding material made of an insulating inorganic material as described above is placed at a position where the peripheral portion 15A of the lid 15 is to be bonded. It apply | coats in thin film form and mounts so that the peripheral part 15A of the cover body 15 may contact the position where this joining material A was apply | coated.
At this time, as shown in FIG. 3A, the other discharge electrode 12 formed on the upper surface 11A of the insulating substrate 11 is made of a metal lid through a bonding material A made of an insulating inorganic material. 15 in which the peripheral portion 15A is located (in this state, since the joining material A made of an insulating inorganic material is interposed, the peripheral portion 15A of the other discharge electrode 12 and the lid 15 is provided. The one discharge electrode 13 is inclined so as to approach the lower surface of the insulating substrate 11 from the middle part toward the base end part 13A side, so that the peripheral part of the lid 15 A gap 16 is formed between them without contacting 15A.
[0026]
Next, an insulating material paste such as a glass paste is applied to the gap 16. The glass paste applied to the gap 16 has many gaps and holes before being heated and melted. In addition, the lid body 15 has air permeability between the inside and the outside.
Then, for example, heating is performed in an inert gas suitable for discharge such as He, Ar, Ne, Xe, SF ₆ , CO ₂ , C ₃ F ₈ , C ₂ F ₆ , CF ₄ , H _2, or a mixed gas thereof. Thus, the bonding material A is melted to join the peripheral portion 15A of the lid 15 and the upper surface 11A of the insulating substrate 11, and at the same time, through the glass paste applied to the gap 16. Then, an inert gas is sealed in the internal space of the lid 15 to form a discharge space, and the glass paste is melted and loses air permeability, so that the gap 16 is sealed with the insulating material 17 and sealed. The
In other words, the surge absorber manufacturing method according to the present embodiment simultaneously performs the step of bonding the lid 15 to the insulating substrate 11 and the step of closing the gap 16.
[0027]
When the bonding material A is heated, as shown in FIG. 3B, the bonding material A made of an insulating inorganic material reacts and melts with the inorganic binding material that is a component of the other discharge electrode 12, and the other bonding material A is heated. By being absorbed by the discharge electrode 12 and extinguished, the peripheral portion 15A of the lid 15 and the other discharge electrode 12 are electrically joined and conducted.
At this time, if the thickness to which the bonding material A is applied is smaller than 0.1 μm, the peripheral portion 15A of the lid 15 and the upper surface 11A of the insulating substrate 11 cannot be bonded without any gap, and an inert gas is enclosed. On the other hand, if the thickness is larger than 10 μm, the bonding material A cannot be completely melted by reaction with the inorganic bonding material, and the peripheral edge portion 15A of the lid 15 and the other discharge electrode 12 are electrically bonded. There is a risk that it will not be possible.
[0028]
Finally, terminal electrodes 18 and 18 are formed on both end surfaces 11B and 11B of the insulating substrate 11 by, for example, dipping, on both end surfaces 11B and 11B of the insulating substrate 11, and both end surfaces 11B and 11B of the insulating substrate 11 are formed. The surge absorber 10 having the above-described configuration is manufactured by joining the base end portions 12A, 13A of the discharge electrodes 12, 13 extending to 11B to the terminal electrodes 18, 18.
[0029]
In the manufacturing method as described above, the step of bonding the lid 15 to the insulating substrate 11 and the step of closing the gap 16 existing between the one discharge electrode 13 and the peripheral portion 15A of the lid 15 are simultaneously performed. Therefore, it is possible to reduce the manufacturing process and efficiently manufacture the product.
[0030]
In the present embodiment, the one discharge electrode 13 is inclined so as to approach the lower surface of the insulating substrate 11 from the middle portion toward the base end portion 13A, and the one discharge electrode 13 and the lid body 15 are inclined. A gap 16 is formed between the peripheral edge 15A of the first electrode, but other configurations may be used as long as a gap is formed between the one discharge electrode 13 and the peripheral edge 15A of the lid 15. The gap 16 may be formed on the substrate 11 so as to be stepped lower than the upper surface 11A from the middle part of one of the discharge electrodes 13 to the base end part 13A. A notch may be provided in the peripheral edge portion 15 </ b> A so that a gap 16 is formed between the discharge electrode 13.
[0031]
【The invention's effect】
According to the present invention, in addition to being able to absorb the surge by the discharge gap, the metal lid electrically connected to the other discharge electrode serves as an electrode for collecting surges such as static electricity entering from the space. Static electricity entering through gaps such as device cases and SW pads can be absorbed or released to the ground. In addition, discharge can be performed between one of the discharge electrodes and the metal lid, so that the thermal effect on the discharge electrodes is reduced and the life of the surge absorber can be extended.
In addition, since the lid forming the discharge space is made of metal, the lid can be manufactured at low cost, and the manufacturing cost of the surge absorber can be reduced. Further, by using an insulating substrate, a chip-shaped surge absorber can be obtained, and the surge absorber can be miniaturized and surface-mounted.
[0032]
In addition, since one discharge electrode is provided in the groove formed on the upper surface of the insulating substrate and a part of the peripheral edge of the lid is located above the groove, a gap is formed. By simply forming a groove on the upper surface of the substrate, a gap can be easily formed between the peripheral edge of the lid and one of the discharge electrodes, and the gap can be closed easily by embedding an insulating material in the groove. Can be done.
[0033]
Furthermore, the step of bonding the peripheral portion of the lid to the upper surface of the insulating substrate and the step of closing the gap formed between the one discharge electrode and the peripheral portion of the lid are simultaneously heated in an inert gas. Therefore, the manufacturing process of the surge absorber can be reduced, and efficient manufacturing becomes possible.
[Brief description of the drawings]
FIG. 1 is a perspective view of a surge absorber according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a surge absorber according to an embodiment of the present invention.
3A is an explanatory view showing a state before the bonding material is heated and melted, and FIG. 3B is an explanatory view showing a state after the bonding material is heated and melted.
FIG. 4 is a cross-sectional view showing a conventional surge absorber.
[Explanation of symbols]
10 Surge Absorber 11 Insulating Substrate 11A Upper Surface 12, 13 Discharge Electrodes 12A, 13A Base End 14 Discharge Gap 15 Lid 15A Peripheral 16 Gap 17 Insulating Material 18 Terminal Electrode A Bonding Material

Claims (5)

As the discharge gap is defined in the upper surface of the insulating substrate, and forming a pair of discharge electrodes facing each other, the upper surface of the insulating substrate to the peripheral portion of the lid so as to surround the upper space of the discharge gap A method of manufacturing a surge absorber, comprising: a lid joining step for joining with a joining material; and a gas filling step for filling an inert gas in an internal space formed by the lid,
In the lid bonding step , one discharge electrode is made of a conductive material including a metal powder and an inorganic binder, and a distal end portion is positioned on the upper surface of the insulating substrate and a base end portion is an upper surface of the insulating substrate. Forming the other discharge electrode on the upper surface of the insulating substrate, and forming the bonding material made of an insulating inorganic material on the metal lid. The lid is applied to at least one of the peripheral edge or the other discharge electrode , the lid is placed on the upper surface of the insulating substrate, and the lid is partially over the groove. A step of providing a gap between the one discharge electrode and the peripheral portion of the lid, and heating the peripheral portion of the lid to react the bonding material to the inorganic binder. to be extinguished is absorbed into the other discharge electrode is melted , And a step of electrically bonding the peripheral portion of the other discharge electrode and the lid body,
The gas sealing step includes a step of applying an insulating paste capable of venting inside and outside the gap, and heating and melting the insulating paste in the gap in an inert gas atmosphere to make the gap airtight. A method of manufacturing a surge absorber. The method of manufacturing a surge absorber according to claim 1 , wherein the bonding material is melted simultaneously with heating in the step of closing the gap in the gas sealing step. The method of manufacturing a surge absorber according to claim 1 or claim 2, the inorganic binding _{material, SiO 2, B 2 O 3} , Na 2 O, PbO, of ZnO or BaO 1 or more kinds of constituted by glass fine particle mainly comprising oxides, the bonding material, SiO ₂ or 50 wt% or more of SiO ₂ and the balance _Al 2 _O 3, MgO, 1 kind of ZrO ₂ or TiO ₂ or 2 A method of manufacturing a surge absorber, comprising an oxide of a seed or more. The method of manufacturing a surge absorber according to claim 1 or claim 2, the inorganic binding _{material, SiO 2, B 2 O 3} , Na 2 O, PbO, of ZnO or BaO 1 or more kinds of It is composed of glass fine particles mainly composed of an oxide, and the bonding material is composed mainly of one or more oxides of SiO ₂ , B ₂ O ₃ , Na ₂ O, PbO, ZnO or BaO. A method of manufacturing a surge absorber, comprising: A pair of discharge electrodes are formed opposite to each other via a discharge gap defined on the upper surface of the insulating substrate, and a peripheral portion of the lid is surrounded by the insulating substrate so as to surround the space above the discharge gap. A surge absorber that is joined to the upper surface of the metal and in which an inert gas is sealed in an internal space formed by the lid, and is manufactured by the method of manufacturing a surge absorber according to any one of claims 1 to 4. Surge absorber.

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