JP2002260812A - Manufacturing method of surge absorber, and surge absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surge absorber for absorbing the surge intruding from circumferential space, and to contrive miniaturization and surface mounting. SOLUTION: Peripheral part 15a of a metal lid 15 is jointed to a base board 11 having insulation property so as to surround the upper space of a pair of discharge electrodes 12, 13, and a discharge gap 14. A jointing material, used for jointing the lid 15 and the base board 11 having insulation property, is made to react with the inorganic binding material contained in the discharge electrode at other side 12, and made to fuse when heated and fused, and absorbed into the other discharging electrode at other side 12 and disappeared, and electrically joint the discharge electrode at other side 12 with the peripheral part 15a of a metal lid 15, and makes them conductive with each other. The discharge electrode at one side 13 is sloped to the lower surface of the base board 11 having insulation property as it goes to the base end part 13A from the middle part. A gap 16 is formed between the discharge electrode at one side 13 and the peripheral part 15a of the lid 15. The gap 16 is blocked by an insulation material 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a surge absorber used to protect various devices from surges and prevent accidents, and to a surge absorber.

[0002]

2. Description of the Related Art A portion where electronic equipment for communication equipment such as a telephone, a facsimile, and a modem is connected to a communication line, or
For parts that are susceptible to electric shock such as lightning surges or static electricity (surge voltage) such as RT drive circuits, the abnormal voltage prevents electronic equipment and the printed circuit board on which it is mounted from being damaged by thermal damage or fire. For this purpose, a surge absorber is connected.

FIG. 4 shows an example of such a surge absorber. As shown in FIG. 4, the surge absorber 1 has cap electrodes 5 and 5 at both ends of an absorber element having a conductive film 3 having a discharge gap 4 (micro gap) formed on a peripheral surface of a cylindrical ceramic member 2. The covered glass is housed in a cylindrical glass tube 7 together with an inert gas, and the cylindrical glass tube 7
A pair of sealing electrodes 6 and 6 are opposed to each other at both ends, and are sealed by high-temperature heating to form a glass tube sealing type.

[0004]

However, the conventional surge absorber 1 as described above has a structure of a circuit electrically connected by two lead wires 6A, 6A connected to the sealing electrodes 6, 6, respectively. It absorbs only surges and cannot deal with surges such as static electricity that enter from space. In addition, since such a glass tube sealed surge absorber 1 is manufactured by enclosing an absorber element and an inert gas in the glass tube 7, the product has a cylindrical shape and is not suitable for surface mounting. Further, in the case where the absorber element is sealed in the glass tube 7 in this way, the size is relatively large, and it has been difficult to meet the demand for miniaturization that has been increasing in recent years.

The present invention has been made in view of the above problems, and provides a method of manufacturing a surge absorber and a surge absorber that can absorb a surge of static electricity or the like invading from a space, can be surface-mounted, and can be reduced in size. The purpose is to:

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems,
In order to achieve such an object, the present invention provides a method in which a pair of discharge electrodes are formed on an upper surface of an insulating substrate so as to face each other via a discharge gap, and a cover is formed so as to surround a space above the discharge electrodes. A method for manufacturing a surge absorber, comprising: a lid joining step of joining a peripheral portion of a body to an upper surface of the insulating substrate with a joining material; and a gas filling step of filling an inert gas into an internal space formed by the lid. In the lid bonding step, a step of forming the discharge electrode on a top surface of the insulating substrate with a conductive material including a metal powder and an inorganic binder, and the bonding material made of an insulating inorganic material It is applied to at least one of the peripheral portion of the metal lid or the discharge electrode, and the lid is placed on the upper surface of the insulating substrate, and one of the discharge electrodes and the peripheral portion of the lid. Provide a gap between By heating the peripheral portion of the lid body and reacting and melting the bonding material in the inorganic binder to be absorbed and extinguished by the discharge electrode, the other of the discharge electrodes and the peripheral portion of the lid body are heated. And a step of applying an electrically insulating paste capable of ventilating inside and outside the gap, and applying the insulating paste in the gap in an inert gas atmosphere. Heating and melting to close the gap in an airtight state.

In the surge absorber manufactured by such a manufacturing method, a metal cover is electrically connected to the other discharge electrode. It can be an electrode for collecting surges, which makes it possible to absorb static electricity entering through gaps in the device case, SW pad, etc. or to escape to the ground. Further, discharge can be performed between one discharge electrode and a metal lid that is not electrically connected to the one discharge electrode, so that a thermal effect on the discharge electrode can be reduced. In addition, since the lid forming the discharge space (the internal space formed by the lid) is made of metal, the lid can be manufactured at low cost.
In addition, the use of the insulating substrate makes the whole chip-shaped, so that miniaturization and surface mounting can be achieved.

[0008] In the lid joining step, a groove is formed on the upper surface of the insulating substrate, the one discharge electrode is provided in the groove, and the lid is partially covered with the peripheral portion. It is characterized in that the gap is formed by joining so as to be located above the groove. In such a manufacturing method, a gap can be easily formed between the peripheral portion of the lid and one of the discharge electrodes simply by forming a groove on the upper surface of the insulating substrate, and the work of closing the gap can be performed within the groove. This can be easily performed by embedding an insulating material paste in the substrate.

Further, the method of manufacturing a surge absorber according to the present invention is characterized in that the bonding material is melted at the same time as the heating in the step of closing the gap in the gas filling step. With such a manufacturing method, the peripheral portion of the lid is joined to the upper surface of the insulating substrate, the gap formed by the peripheral portion of the lid and one of the discharge electrodes is closed, and the inert gas is filled. Can be performed at the same time, and the manufacturing process of the surge absorber can be reduced to improve the manufacturing efficiency.

Further, the inorganic binder is made of SiO ₂ , B ₂ O
_3, Na ₂ O, PbO, and ZnO, or one or more oxides of BaO constituted by glass fine particle mainly, the bonding material, SiO ₂ or 50 wt%
The above-mentioned SiO ₂ and the remainder are oxides of one or more of Al ₂ O ₃ , MgO, ZrO _{2 and} TiO ₂ , or SiO ₂ , B ₂ O ₃ , Na ₂ O, PbO, ZnO or BaO It is preferable to use a glass mainly containing one or more oxides of the above.

[0011]

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 sectional view of the surge absorber in FIG.

[0012] The surge absorber 10 according to the present embodiment.
As shown in FIG. 1 and FIG. 2, a conductive material containing a metal powder and an inorganic binder is formed on an upper surface 11A of an insulating substrate 11 made of an insulating material such as alumina. Pair of discharge electrodes 1 made of conductive material
2 and 13 are formed so as to face each other, and a discharge gap 14 (micro gap) having a predetermined dimension is formed between the tip of one discharge electrode 13 and the tip of the other discharge electrode 12. .

The discharge electrodes 12 and 13 are made of a conductive material containing a metal powder and an inorganic binder. The metal powder is made of, for example, Ag, Au, P
Examples thereof include noble metals such as d and Pt, and powders obtained by mixing them (high melting point metals such as Ti, Ta, and W, or compounds thereof). The inorganic binder is, for example, S.
iO ₂ , B ₂ O ₃ , Na ₂ O, PbO, ZnO or BaO
One or more oxides of which are the main components,
Glass fine particles such as borosilicate glass, zinc borate glass, cadmium borate glass, and lead zinc silicate glass are exemplified.

Further, on the upper surface 11A of the insulating substrate 11, the discharge electrodes 12, 13 are respectively connected to the base ends 12A,
13A are opposite end faces 11B, 11B of the insulating substrate 11;
Is formed so as to reach each of. Also, on the upper surface 11A of the insulating substrate 11, one of the discharge electrodes 1 is provided.
A groove 11C is provided in a portion where the third electrode 3 is formed, and in one discharge electrode 13, an insulating substrate is provided along the groove 11C from the midway portion to the base end 13A toward the base end 13A. 11 is inclined toward the lower surface. That is, one discharge electrode 13 is provided in the groove 11 </ b> C from the middle part to the base end 13 </ b> A, and only the front end is formed on the upper surface 11 </ b> A of the insulating substrate 11.
Will be located above.

As shown in FIGS. 1 and 2, the upper surface 11A of the insulating substrate 11 on which the discharge electrodes 12 and 13 are formed is formed to surround the space above the discharge electrodes 12 and 13 and the discharge gap 14. The peripheral portion 15A of the lid 15 is joined by a joining material. The lid body 15 is made of a metal such as Kovar, which has a bottomed annular shape and has a flange-shaped peripheral portion 15A whose diameter is increased one step in the radial direction.

Here, the lid 15 and the insulating substrate 11 are connected.
The bonding material used for bonding is, for example, SiO 2_TwoOr
50% by weight or more of SiO_TwoAnd the balance is Al_TwoO_Three, MgO,
ZrO _TwoOr TiO_TwoOne or more acids of
Insulating inorganic material consisting of a paste made of oxide, or
SiO_Two, B_TwoO_Three, Na_TwoO, PbO, ZnO or Ba
One or more oxides of O as a main component
An insulating inorganic substance made of glass paste
It is applied in a thin film of about 0.1 to 10 μm.

When such a bonding material is heated and melted, the peripheral portion 15A of the lid 15 and the insulating substrate 11
Of the other discharge electrode 12 by reacting and melting the bonding material applied to the upper surface of the other discharge electrode 12 with the inorganic binder, which is a component contained in the discharge electrode 12. Is absorbed and disappears, and the other discharge electrode 12
And the peripheral portion 15A of the lid 15 are electrically connected to each other to conduct electricity. At this time, one of the discharge electrodes 13 is insulated from the insulative substrate 11 toward the base end 13A from the middle.
Is inclined so as to approach the lower surface of the lid 15, so that a predetermined gap 16 is formed without contacting the peripheral edge 15 </ b> A of the lid 15 located above the groove 11 </ b> C.

The one discharge electrode 13 and the metal cover 1
The gap 16 formed between the peripheral portion 15A and the peripheral portion 5A is sealed with an insulating material 17 such as glass. further,
In the internal space formed by the lid 15, for example, H
e, Ar, Ne, Xe, SF 6, CO 2, C 3 F 8, C
₂ F ₆ with a suitable inert gas is sealed, CF _4, H ₂ and discharge of such a mixed gas thereof, the internal space is a discharge space.

Then, both end faces 11B of the insulating substrate 11 are provided.
Discharge electrodes 12, 13 formed to reach 11B
Base ends 12A and 13A of the insulating substrate 11
A surge absorber 10 having a chip shape is formed by being connected to the terminal electrodes 18 and 18 joined to 1B and 11B.

In the surge absorber 10 configured as described above, a pair of discharge electrodes 1 opposed to each other are provided.
The discharge gap 14 formed by the discharge electrodes 2 and 13 not only absorbs surges from circuits and the like connected to the terminal electrodes 18 and 18, but also a metal lid electrically connected to the other discharge electrode 12. 15 can be used as an electrode for absorbing surges such as static electricity invading from the space,
Surges such as static electricity that enter through gaps in the device case, SW pads, and the like can be absorbed or released to the ground. In addition, a discharge can be performed between the one discharge electrode 13 and the metal lid 15 that is not electrically connected to the one discharge electrode 13, and the heat effect on the discharge electrodes 12 and 13 can be reduced. As a result, the life of the surge absorber can be extended.

Further, since the cover 15 forming the discharge space is made of metal, the cover 15 can be manufactured at low cost, and the manufacturing cost of the surge absorber 10 can be reduced. Furthermore, by forming the surge absorber 10 using the insulating substrate 11, the chip-shaped surge absorber 10 can be obtained, and its size and surface mounting can be reduced. When the size of the discharge space is changed, only the size of the lid 15 needs to be changed, and the size of the discharge space can be easily changed.

Moreover, one of the discharge electrodes 13 extends from the middle to the base end 13A of the upper surface 11 of the insulating substrate 11.
A is provided in the groove 11C formed in the groove A, and the gap 16 is formed by joining a part of the peripheral edge 15A of the lid 15 so as to be located above the groove 11C. Only by forming the groove 11C on the upper surface 11A, the gap 16 can be easily formed between the peripheral portion 15A of the lid 15 and one of the discharge electrodes 13, and the gap 1 can be easily formed.
6 can be easily performed by embedding the insulating material 17 in the groove 11C.

Hereinafter, a method of manufacturing the surge absorber 10 having the above configuration will be described. First, as shown in FIG. 1, an insulation formed with a groove 11 </ b> C for inclining one discharge electrode 13 so as to approach the lower surface of the insulating substrate 11 from the middle part toward the base end 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.

The discharge electrodes 12 and 13 are formed in the grooves 11C by sputtering, vapor deposition, ion plating, printing, printing, or the like using a conductive material containing a metal powder and an inorganic binder as described above. After forming one strip-shaped thin film in the direction along, the laser beam is irradiated and cut at an intermediate position of the strip-shaped thin film, that is, a position where the discharge gap 14 is to be formed, so that the cut portion becomes the discharge gap 14. , Discharge electrodes 12 and 13 facing each other are formed.

Next, on the upper surface 11A of the insulating substrate 11, a position where the peripheral portion 15A of the lid 15 is to be joined is
The bonding material made of an insulating inorganic material as described above is applied in the form of a thin film having a thickness of about 0.1 to 10 μm, and the peripheral portion 15A of the lid 15 is brought into contact with the position where the bonding material A is applied. As shown. At this time, the other discharge electrode 12 formed on the upper surface 11A of the insulating substrate 11 is
As shown in FIG. 3A, the peripheral portion 15A of the metal lid 15 is positioned on the intermediary of a bonding material A made of an insulating inorganic material. Since the bonding material A made of a conductive inorganic material is interposed, the other discharge electrode 12 and the peripheral portion 15A of the lid 15 are not electrically connected to each other). By being inclined toward the lower surface of the insulating substrate 11, the gap 16 is formed between the lid 15 and the peripheral portion 15 </ b> A without contact with the peripheral portion 15 </ b> A.

Next, an insulating material paste such as a glass paste is applied to the gap 16, and the glass paste applied to the gap 16 has many gaps and holes before being heated and melted. It has air permeability between the inside and the outside of the lid 15. And, for example, He, Ar, Ne, Xe, SF ₆ , CO ₂ , C ₃ F ₈ ,
By heating in an inert gas suitable for electric discharge such as C ₂ F ₆ , CF ₄ , H _2, or a mixture thereof, the above-described bonding material A is melted and insulated from the peripheral portion 15A of the lid 15. At the same time as bonding with the upper surface 11A of the conductive substrate 11, the inert gas is sealed in the inner space of the lid 15 through the glass paste applied to the gap 16 to form a discharge space. The paste melts and loses air permeability, and the gap 16 is closed by the insulating material 17 to be sealed. That is, in the method of manufacturing the surge absorber according to the present embodiment, the step of joining the lid 15 to the insulating substrate 11 and the step of closing the gap 16 are performed simultaneously.

When heating the bonding material A, FIG.
As shown in (b), bonding material A made of an insulating inorganic material
Reacts and melts with the inorganic binder, which is a component of the other discharge electrode 12, and is absorbed by the other discharge electrode 12 and disappears, so that the peripheral portion 15A of the lid 15 and the other discharge electrode 12
Are electrically connected to each other to conduct. 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 a gap, and an inert gas is filled. On the other hand, if the thickness is larger than 10 μm, the bonding material A cannot completely react and melt with the inorganic binder, and the peripheral portion 15A of the lid 15 and the other discharge electrode 12 are electrically bonded. May not be able to be performed.

Finally, both end surfaces 11B of the insulating substrate 11
11B, the terminal electrode 1 is formed by a dipping method, for example.
8, 18 are formed on both end faces 11B, 11B of the insulating substrate 11, and both end faces 11B, 11B of the insulating substrate 11 are formed.
B, the base ends 12A, 13 of the discharge electrodes 12, 13
A is joined to the terminal electrodes 18 to manufacture the surge absorber 10 having the above-described configuration.

In the above-described manufacturing method, the step of bonding the lid 15 to the insulating substrate 11 and the step of closing the gap 16 existing between one of the discharge electrodes 13 and the peripheral portion 15A of the lid 15 are performed. Can be performed at the same time, which leads to a reduction in the number of manufacturing steps, and an efficient product can be manufactured.

In the present embodiment, one of the discharge electrodes 13 is inclined so as to approach the lower surface of the insulating substrate 11 from the intermediate portion toward the base end 13A side. A gap 16 is formed between the cover 15 and the peripheral portion 15A.
Another configuration may be used as long as a gap is formed between the upper electrode 11A and the peripheral portion 15A of the lid 15, for example, from the upper surface 11A of the insulating substrate 11 from the middle of one of the discharge electrodes 13 to the base end 13A. The gap 16 may be formed so as to form a step so as to be one step lower. Further, a notch is provided in the peripheral portion 15A of the lid 15 so that one of the discharge electrodes 1 is formed.
A gap 16 may be formed between the gap 3 and the gap 3.

[0031]

According to the present invention, the surge can be absorbed by the discharge gap, and the metal lid electrically connected to the other discharge electrode collects surges such as static electricity that enter from the space. To become an electrode, equipment case, SW
It can absorb static electricity that enters from gaps such as pads or escape to the ground. Moreover, a discharge can be performed between one discharge electrode and the metal lid,
The influence of heat on the discharge electrode is reduced, and the life of the surge absorber can be extended. In addition, since the lid that forms 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 size and surface mounting of the surge absorber can be reduced.

In addition, one of the discharge electrodes is provided in the groove formed on the upper surface of the insulating substrate, and a part of the peripheral portion of the lid is located above the groove to form a gap. By simply forming a groove on the upper surface of the insulating substrate, a gap can be easily formed between the peripheral portion of the lid and one of the discharge electrodes, and the gap can be closed by embedding an insulating material in the groove. This can be easily performed.

Further, 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 one discharge electrode and the peripheral portion of the lid are performed in an inert gas. And heating at the same time, the number of manufacturing steps 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 sectional view of a surge absorber according to the embodiment of the present invention.

FIG. 3A is an explanatory view showing a state before heating and melting a joining material, and FIG. 3B is an explanatory view showing a state after heating and melting a joining material.

FIG. 4 is a cross-sectional view showing a conventional surge absorber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Surge absorber 11 Insulating substrate 11A Upper surface 12, 13 Discharge electrode 12A, 13A Base end 14 Discharge gap 15 Lid 15A Peripheral part 16 Gap 17 Insulating material 18 Terminal electrode A Bonding material

Claims (6)

[Claims] 1. A pair of discharge electrodes are formed on an upper surface of an insulating substrate so as to face each other via a discharge gap.
A lid bonding step of bonding the peripheral portion of the lid to the upper surface of the insulating substrate with a bonding material so as to surround the space above the discharge electrodes, and filling an inert gas into an internal space formed by the lid. A method of manufacturing a surge absorber having a gas filling step, wherein the lid bonding step is a step of forming the discharge electrode on a top surface of the insulating substrate using a conductive material including a metal powder and an inorganic binder. Applying the bonding material made of an insulating inorganic material to at least one of a peripheral portion of the metal lid and the discharge electrode, placing the lid on an upper surface of the insulating substrate, and setting the discharge electrode Providing a gap between one of the two and the peripheral portion of the lid, and heating the peripheral portion of the lid to react and melt the bonding material in the inorganic binder and absorb and disappear in the discharge electrode. By allowing Electrically connecting the other of the electrodes to the peripheral portion of the lid, wherein the gas filling step includes applying an insulating material paste through which air can flow inside and outside the gap; Heating and melting the insulating paste in the gap in an active gas atmosphere to close the gap in an airtight state. 2. The method of manufacturing a surge absorber according to claim 1, wherein in the lid joining step, a groove is formed on an upper surface of the insulating substrate, and the one discharge electrode is provided in the groove. The surge absorber is characterized in that the lid is joined so that a part of a peripheral portion thereof is located above the groove, thereby forming the gap. 3. 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 filling step. Absorber manufacturing method. 4. The method of manufacturing a surge absorber according to claim 1, wherein the inorganic binder is made of SiO ₂ , B ₂ O ₃ , Na ₂ O, Pb.
The bonding material is composed of glass fine particles mainly containing one or more oxides of O, ZnO and BaO, and the bonding material is made of SiO ₂ or 50 wt% or more of SiO _2.
A method of manufacturing a surge absorber, wherein the remainder is composed of one or more oxides of Al ₂ O ₃ , MgO, ZrO ₂ or TiO ₂ . 5. The method for manufacturing a surge absorber according to claim 1, wherein the inorganic binder is made of SiO ₂ , B ₂ O ₃ , Na ₂ O, Pb.
It is composed of glass fine particles containing one or more oxides of O, ZnO or BaO as a main component, and the bonding material is made of SiO ₂ , B ₂ O ₃ , Na ₂ O, PbO, Z
A method for manufacturing a surge absorber, comprising a glass mainly containing one or more oxides of nO or BaO. 6. A pair of discharge electrodes are formed on an upper surface of an insulating substrate so as to face each other with a discharge gap therebetween, and a peripheral portion of the lid is formed of the insulating material so as to surround a space above the discharge electrodes. A surge absorber joined to an upper surface of a substrate and filled with an inert gas in an internal space formed by the lid, manufactured by the method of manufacturing a surge absorber according to claim 1. Surge absorber to be used.