JP4419599B2 - Chip-type surge absorber and manufacturing method thereof - Google Patents

Description

  The present invention relates to a chip-type surge absorber used for protecting various electronic devices and the like from surges and preventing accidents, and a method for manufacturing the same.

  Surge absorbers are connected to parts where electronic devices such as telephones and modems are connected to communication lines, or parts that are susceptible to electric shock caused by abnormal voltage such as lightning surge or static electricity, such as CRT drive circuits, and are caused by abnormal voltage entering from outside Used to prevent electronic equipment from being destroyed.

  Various types of such surge absorbers are known, and one of them is provided with an insulating tube made of glass or the like and a pair of sealing electrodes. The tubular body is formed in a cylindrical shape, and a conductive film is deposited on the inner peripheral surface thereof. In this conductive film, a micro gap is formed so as to divide the conductive film in the axial direction at a substantially central portion in the longitudinal direction of the tubular body. The pair of sealing electrodes are sealed at both ends of the tubular body and are electrically connected to the conductive film. In addition, an inert gas is sealed in the tube.

In this surge absorber, when an abnormal voltage (surge voltage) is applied to a pair of sealing electrodes, glow discharge is triggered in the micro gap. This discharge reaches both ends of the tube along the conductive film, and arc discharge is finally generated between a pair of sealing electrodes opposed to each other. As a result, the surge voltage is absorbed by the surge absorber and the electronic device or the like is protected.
Here, in many cases, solder or the like is interposed between the tube body and the pair of sealing electrodes to improve contact. In this case, when a surge current (discharge current) flows, flux and solder are They can decompose and scatter into the tube. If the scattered part accumulates in the microgap, the insulating property of the microgap deteriorates and adversely affects the life of the surge absorber. Therefore, it is preferable that the depth and width of the microgap can be arbitrarily set.

Here, as a method of manufacturing the surge absorber as described above, after a conductive film is deposited on the entire tube body, this is placed in a carbon heater to heat the entire body, and sealed at both ends of the tube body Each electrode is welded. At this time, an inert gas is introduced into the tube and sealed. Thereafter, the conductive coating on the outer peripheral surface of the tube is removed, laser is irradiated from the outside of the tube, and the conductive coating on the inner peripheral surface of the tube is cut to form a micro gap to obtain a surge absorber. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 07-022152 (paragraph numbers 0008-0015, FIGS. 1 and 2)

  By the way, in the conventional method of manufacturing a surge absorber, a laser is irradiated from the outside of the tubular body, and the conductive film on the inner peripheral surface of the tubular body is cut to form a micro gap. Therefore, there is a problem that the depth of the micro gap cannot be made larger than the thickness of the conductive film, and it is difficult to form the depth of the micro gap deeply. In addition, since the microgap is formed by laser irradiation, there is a problem that it is difficult to form the width wide and with high accuracy. Further, for the same reason, there is a problem in that the conductive layers are opposed to each other with the microgap interposed therebetween. Since the end face of the conductive film has a sawtooth shape when viewed microscopically, there is a problem that the discharge start voltage between the films is not stable.

  The present invention has been made in consideration of such circumstances, and can provide a chip-type surge absorber that can set the depth and width of the microgap with high precision and ease, and has a stable discharge start voltage, and its manufacture. It aims to provide a method.

In order to solve the above-described problems and achieve such an object, the present invention proposes the following means.
The chip type surge absorber according to the present invention includes a first insulating element having a first through hole, an intermediate insulating plate having an intermediate through hole, and a second insulating element having a second through hole. The through-holes are joined in such a state that the through-holes are connected in order, and both end portions of the through-holes configured by the connected through-holes are sealed with sealing electrodes, and the first through-hole and the second through-hole are sealed. only the inner peripheral surface of the through hole, the connected conductive film on the sealing electrodes are deposited, a portion of one of the sealing electrodes, disposed in said first through hole, the other A part of the sealing electrode is arranged in the second through hole .

In this chip-type surge absorber, the intermediate through hole formed in the intermediate insulating plate can be a so-called micro gap, so the setting of the depth of the micro gap sets the diameter of the intermediate through hole, The setting can be performed by setting the thickness of the intermediate insulating plate. That is, the depth and width of the microgap can be set easily and with high accuracy.
Further, among the outer surfaces of the conductive film deposited on the inner peripheral surfaces of the first and second through holes, the end surfaces facing each other across the micro gap can be easily made smooth. The discharge start voltage can be reliably stabilized.

  The chip type surge absorber according to the present invention is the chip type surge absorber according to claim 1, wherein the intermediate through hole, the first through hole, and the second through hole are formed coaxially, The intermediate through hole has an inner diameter larger than that of the first through hole and the second through hole.

  In this chip type surge absorber, the first and second through holes are formed coaxially, and the intermediate through hole has an inner diameter larger than that of the first and second through holes. A gap can be easily obtained. Therefore, a surge current flows through the chip-type surge absorber, and flux and the like interposed between the sealing electrode and the first and second insulators are decomposed and scattered, and the scattered one Even when the portion is deposited in the micro gap, it is possible to reliably suppress the deterioration of the insulating property of the micro gap and the shortening of the life of the surge absorber.

The method of manufacturing a chip-type surge absorber according to the present invention includes a first insulating substrate having a plurality of first through-holes having a conductive film formed on an inner peripheral surface, and an intermediate insulation having a plurality of intermediate through-holes. A bonding step in which a substrate and a second insulating substrate having a plurality of second through-holes each having a conductive film formed on an inner peripheral surface are joined in this order with the through-holes in communication with each other; A step of cutting the laminated plate into a lattice shape to form a chip body, and sealing both ends of the through holes formed by the through holes in the communication state with sealing electrodes, The conductive film is connected , a part of one of the sealing electrodes is disposed in the first through hole and a part of the other sealing electrode is disposed in the second through hole. And a sealing process.

  Further, the chip type surge absorber manufacturing method of the present invention is the chip type surge absorber manufacturing method according to claim 3, wherein the first insulating substrate and the second insulating substrate each have a lattice-shaped first surface. One scribe line and a second scribe line are formed, and the cutting step cuts along the first and second scribe lines.

  The chip type surge absorber manufacturing method according to the present invention is the chip type surge absorber manufacturing method according to claim 4, wherein the first insulating substrate and the second insulating substrate are the first and second grids. A green sheet forming step of forming the first and second through holes in the first and second green sheets for ceramics respectively formed with the second scribe line; and the first and second green sheets. The sheet is manufactured through a baking step of baking the sheet and a film forming step of forming a conductive film on the inner peripheral surfaces of the first through hole and the second through hole after baking.

In these chip type surge absorber manufacturing methods, a microgap having a high depth and width can be easily formed, and a chip capable of suppressing the insulation degradation of the microgap and the shortening of the life of the surge absorber. Type surge absorber can be formed easily and at low cost.
Moreover, since the end faces facing each other across the micro gap can be easily made smooth among the surfaces of the conductive film deposited on the inner peripheral surfaces of the first and second through-holes, A chip-type surge absorber having a stable discharge start voltage between the conductive films can be formed reliably and at low cost.
Furthermore, the first insulating substrate and the second insulating substrate have a lattice-shaped first scribe line and second scribe line formed on the surface, respectively, and the cutting step includes the first and second scribe lines. Since cutting is performed along the scribe line, this cutting can be performed easily and with high accuracy.

According to the chip type surge absorber and the manufacturing method thereof according to the present invention, it is possible to easily form a microgap having a high depth and width, and to reduce the insulation property of the microgap and to shorten the life of the surge absorber. It is possible to provide a chip-type surge absorber that can suppress the increase in the size.
Further, among the outer surfaces of the conductive film deposited on the inner peripheral surfaces of the first and second through holes, the end surfaces facing each other across the micro gap can be easily made smooth. The discharge start voltage can be reliably stabilized.

Hereinafter, an embodiment of a chip-type surge absorber and a manufacturing method thereof according to the present invention will be described with reference to FIGS.
The chip type surge absorber 1 shown in FIG. 1 includes a first insulating element 2 having a first through hole 2a, an intermediate insulating plate 3 having an intermediate through hole 3a, and a second having a second through hole 4a. The insulating bodies 4 are joined in this order with the through holes 2a, 3a, 4a in communication. In the present embodiment, each of the through holes 2a, 3a, 4a is formed coaxially, and the intermediate through hole 3a has an inner diameter larger than that of the first through hole 2a and the second through hole 4a. Yes.

Then, both end portions of the through holes constituted by the through holes 2a, 3a, 4a in the communication state are sealed electrodes 5 via a brazing material 15 made of Ag, Ag-Cu, Ag-In, or the like. The conductive film 6 connected to the sealing electrode 5 is attached only to the inner peripheral surfaces of the first through hole 2a and the second through hole 4a. Here, the first and second insulators 2 and 4 and the intermediate insulating plate 3 are made of, for example, a ceramic material made of Al ₂ O ₃ or the like. The first and second insulators 2 and 4 are formed with a thickness (size in the communication direction) of, for example, 0.5 mm to 1.5 mm, and the intermediate insulating plate 3 has a thickness of, for example, It is formed at 30 μm or more and 50 μm or less.

  In the above configuration, the chip type surge absorber 1 has a conductive film 6 deposited on the inner peripheral surfaces of the first and second through holes 2a and 4a so that the through holes 2a, 3a and 4a communicate with each other. A microgap 8 is provided so that the film 6 is divided at substantially the center in the direction. That is, the depth of the micro gap 8 is set by the distance between the inner peripheral surface of the intermediate through hole 3 a and the surface of the conductive film 6, and the width is set by the thickness of the intermediate insulating plate 3. It has become.

The sealing electrode 5 is formed of a Fe—Ni 42% alloy in a two-stage columnar shape, and includes a large diameter portion 5a and a small diameter portion 5b. The outer diameter of the large diameter portion 5a is formed to be substantially the same as the outer diameter of the first and second insulators 2 and 4, and the outer diameter of the small diameter portion 5b is electrically conductive on the inner peripheral surface. The first and second through holes 2a and 4a provided with the conductive film 6 are formed to be approximately the same or slightly smaller in inner diameter, and the outer peripheral surface of the small diameter portion 5b and the surface of the conductive film 6 are connected. Yes. Here, a mixed gas such as argon gas, neon gas, nitrogen gas or the like is sealed in the internal space 9 sealed by the small diameter portion 5b, the conductive film 6, and the intermediate through hole 3a.
The chip-type surge absorber 1 is connected via a sealing electrode 5 to a communication circuit of a communication device such as a telephone, a facsimile, or a modem.

  In the surge absorber 1 configured as described above, when an abnormal voltage (surge voltage) is generated due to lightning or static electricity, the surge voltage is applied to the sealing electrode 5. The applied voltage reaches the micro gap 8 through the conductive film 6 and causes a strong electric field concentration to cause creeping discharge (glow discharge). This discharge reaches the end of the first and second insulators 2 and 4 on the side where the sealing electrode 5 is formed along the conductive film 6, and finally a pair of sealing electrodes facing each other. An arc discharge is generated between the five. Thereby, the chip-type surge absorber 1 can absorb a surge voltage and can protect a circuit.

Next, a manufacturing method of the chip type surge absorber 1 configured as described above will be described with reference to FIGS.
First, lattice-shaped first and second scribe lines L1 and L2 were defined by the first and second scribe lines L1 and L2 in the first and second green sheets for ceramics, respectively. First and second through-holes 2a and 4a are formed at substantially central portions in each lattice. And after baking these 1st, 2nd green sheets, the chemical vapor deposition method (CVD method), the electroless plating method, etc. on the internal peripheral surface of the 1st through-hole 2a and the 2nd through-hole 4a The first and second insulating substrates 20 and 21 are formed by forming the conductive film 6 such as the Mo—Mn layer and the Mo—W layer by the film forming method.
Further, a plurality of intermediate through holes 3a are formed on the surface of the intermediate insulating substrate 22 made of a ceramic material via a predetermined gap. At this time, as described above, the intermediate through hole 3a is formed larger in diameter than the inner diameters of the first and second through holes 2a and 4a, and the first and second through holes 2a and 4a are disposed. It is formed with the same pitch as the pitch.

  As shown in FIGS. 2 and 3, the first insulating substrate 20, the intermediate insulating substrate 22, and the second insulating substrate 21 communicate with the through holes 2a, 3a, and 4a in this order. Specifically, the laminated plate 23 is formed by bonding via a brazing material (not shown) so that they are arranged on the same axis.

  Next, after the laminated plate 23 is cut into a lattice shape along the first and second scribe lines L1 and L2 to form the chip body 24, the first and second surfaces are formed on the front and back surfaces of the chip body 24. The brazing material 15 is placed so as to avoid the through holes 2 a and 4 a and to be in contact with at least a part of the end face of the conductive film 6. Then, the sealing electrode 5 is placed on the surface of the brazing material 15 as shown in FIG. 1, and both end portions of the through holes formed by the through holes 2a, 3a, 4a in the communication state are sealed. The sealing electrode 5 and the conductive film 6 are connected by sealing with the stop electrode 5. In this state, these are put in a carbon heater (not shown) and heated as a whole, and the sealing electrodes 5 are welded to the front and back surfaces of the chip body 24, respectively. At this time, a mixed gas such as argon gas, neon gas, nitrogen gas or the like is introduced into the internal space 9 defined by the sealing electrode 5, the conductive film 6, and the intermediate through hole 3a, and these are sealed. A mold surge absorber 1 is formed.

As described above, according to the chip type surge absorber and the manufacturing method thereof according to the present embodiment, the first and second through holes 2a and 4a are formed in the first and second insulators 2 and 4, respectively. In addition, the conductive film 6 is formed on the inner peripheral surface, the intermediate through hole 3a is formed in the intermediate insulating plate 3, and the through holes 2a, 3a, 4a are in communication with each other. Since the first insulating element 2, the intermediate insulating plate 3, and the second insulating element 4 are laminated and joined in this order, the intermediate through hole 3a can be formed as the micro gap 8. Therefore, the depth of the microgap 8 can be set by setting the inner diameter of the intermediate through hole 3a, and the width can be set by setting the thickness of the intermediate insulating plate 3. Thereby, the depth and width of the microgap 8 can be set easily and with high accuracy.
Further, since it is not necessary to cut the conductive film 6 with a laser when forming the microgap 8, the end surfaces of the conductive film 6 facing each other across the microgap 8 can be easily made smooth. Can do. Therefore, the discharge start voltage between the conductive films 6 can be reliably stabilized.

  Further, since the intermediate through hole 3a is formed to have a larger diameter than the first and second through holes 2a and 4a and these are arranged coaxially with each other, the deep microgap 8 can be easily formed. Can be formed. Therefore, a surge current flows through the chip-type surge absorber 1 and the flux interposed between the sealing electrode 5 and the first and second insulators 2 and 4 is decomposed and scattered. Even if the scattered part accumulates in the micro gap 8, it is possible to reliably suppress the deterioration of the insulating property of the micro gap 8 and the shortening of the life of the surge absorber 1.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is possible to provide a chip type surge absorber that can easily form a microgap having a high depth and width, and can suppress the deterioration of the insulation property of the microgap and the shortening of the life of the surge absorber.
Further, among the outer surfaces of the conductive film deposited on the inner peripheral surfaces of the first and second through holes, the end surfaces facing each other across the micro gap can be easily made smooth. The discharge start voltage can be reliably stabilized.

In one Embodiment which concerns on this invention, it is side surface sectional drawing which shows a chip type surge absorber. In one Embodiment which concerns on this invention, it is a top view which shows a laminated body. FIG. 3 is a cross-sectional view of the laminate shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chip type surge absorber 2 1st insulating element 2a 1st through-hole 3 Intermediate insulating plate 3a Intermediate through-hole 4 2nd insulating element 4a 2nd through-hole 5 Sealing electrode 6 Conductive film 8 Microgap 20 First Insulating Substrate 21 Second Insulating Substrate 22 Intermediate Insulating Substrate 23 Laminated Body 24 Chip Body L1 First Scribe Line L2 Second Scribe Line

Claims (5)

The first insulating element having the first through hole, the intermediate insulating plate having the intermediate through hole, and the second insulating element having the second through hole bring the through holes into communication in this order. Joined together
Both end portions of the through holes constituted by the respective through holes in a communication state are sealed with a sealing electrode,
A conductive film connected to the sealing electrode is attached only to the inner peripheral surfaces of the first through hole and the second through hole,
A part of one of the sealing electrodes is disposed in the first through hole ,
A chip-type surge absorber , wherein a part of the other sealing electrode is disposed in the second through hole . In the chip type surge absorber according to claim 1,
The intermediate through hole, the first through hole, and the second through hole are each formed on the same axis,
The tip type surge absorber, wherein the intermediate through hole has an inner diameter larger than that of the first through hole and the second through hole. A first insulating substrate having a plurality of first through-holes having a conductive coating formed on the inner peripheral surface, an intermediate insulating substrate having a plurality of intermediate through-holes, and a conductive coating formed on the inner peripheral surface A joining step in which a plurality of second through-holes and a second insulating substrate are joined in this order with the through-holes in communication with each other;
A cutting step of cutting the laminated plate into a lattice to form a chip body;
Both ends of the through-holes formed by the through-holes in the communication state are sealed with a sealing electrode to connect the sealing electrode and the conductive film, and a part of the one sealing electrode is chip type surge absorber, characterized in that a sealing step of the part of the first other of the sealing electrodes while being disposed in the through hole is disposed in the second through hole Manufacturing method. In the manufacturing method of the chip type surge absorber according to claim 3,
The first insulating substrate and the second insulating substrate have a lattice-shaped first scribe line and second scribe line formed on the surface, respectively.
The method of manufacturing a chip type surge absorber, wherein the cutting step cuts along the first and second scribe lines. In the manufacturing method of the chip type surge absorber according to claim 4,
The first insulating substrate and the second insulating substrate are:
A green sheet forming step of forming the first and second through holes in the first and second green sheets for ceramics in which the grid-like first and second scribe lines are respectively formed;
A firing step of firing the first and second green sheets;
A chip type surge absorber manufacturing method, wherein the chip type surge absorber is manufactured through a film forming step of forming a conductive film on the inner peripheral surfaces of the first through hole and the second through hole after firing.

Images