JP3508574B2 - Chip type surge absorber - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portion where an electronic device such as a telephone or a modem is connected to a communication line, or a portion such as a CRT drive circuit, which is susceptible to electric shock due to an abnormal voltage such as lightning surge or static electricity. The present invention relates to a chip type surge absorber used to prevent electronic devices from being destroyed by voltage.

[0002]

2. Description of the Related Art The following is an example of such a chip type surge absorber.

As shown in FIG. 9, an alumina substrate 51 having a pair of discharge electrodes 51A and 51B formed on a plate surface with a discharge gap (microgap) formed therein, and an opening 52A for forming a discharge chamber are provided in a central portion of the plate. The formed alumina substrate 52 and the non-opened alumina substrate 53 (FIG. 9A) are arranged in this order.
A chip-type surge absorber (FIG. 9B) in which glass paste is laminated and integrated, and the discharge chamber is filled with a sealed gas atmosphere to form a surge absorber element 54 and terminal electrodes 55A and 55B are formed on both end surfaces thereof. As shown in FIG. 10, an alumina substrate 61 having a discharge electrode 61A formed on the plate surface and an alumina substrate 63 having a discharge electrode 63A formed on the plate surface are provided with an opening 62A for forming a discharge chamber at the center of the plate. Through the alumina substrate 62 (see FIG.
(A)), a chip type surge absorber (FIG. 10 (b) in which the surge absorber element body 64 is formed by stacking and integrating the glass paste and using the discharge chamber as an enclosed gas atmosphere to form terminal electrodes 65A and 65B on both end faces thereof. )). As shown in FIG. 11, a chip type surge absorber in which discharge electrodes 71A, 71B and terminal electrodes 72A, 72B are formed on one plate surface of an alumina substrate 71 and discharged in the atmosphere.

As shown in FIG. 12, an alumina substrate 81 having a pair of discharge electrodes 81A and 81B formed on a plate surface with a discharge gap (microgap) and an alumina substrate having a groove 82A for forming a discharge chamber are formed. 82 and the discharge electrode 8
1A, 81B and the groove 82A are overlapped so that they face each other (FIG. 12A), and they are bonded by the glass layer 83 (FIG. 12A).
(B)) A chip type surge absorber (Fig. 12) in which the cap electrodes 84A and 84B are adhered to both end faces and the discharge chamber formed by the groove 82A has a filled gas atmosphere.
(C)). In FIG. 12, reference numeral 85 is a conduction electrode,
86 is a glass layer for adhesion, and 87 is an adhesion layer. The surge absorbers 1 to 3 have the following problems.

In the chip type surge absorber, since the discharge occurs in the atmosphere, the discharge start voltage is not stable under the influence of atmospheric humidity, pressure and dust.

In addition, including the chip type surge absorber, the chip type surge absorber, such as the chip type surge absorber, forms a microgap, and after the conductive film is deposited on the alumina substrate, the film is formed by laser. Although it is necessary to form a microgap at the same time, enormous laser processing cost and processing time are required for forming this microgap, which is a factor of high cost.

With the chip type surge absorber of
Although it is not necessary to form the microgap, since the three substrates are stacked, the degree of overlap of the substrates is likely to be displaced, sealing becomes impossible, and the external dimensions vary greatly. The problem of the deviation of the overlapping degree of the substrates can also occur in the chip type surge absorber since the three substrates are superposed.

A chip type surge absorber which solves the above problems and has a discharge chamber in a sealed gas atmosphere, can prevent the deviation of the overlapping condition of the substrates, and can easily perform the sealing. As a chip type surge absorber that can be easily and inexpensively manufactured by omitting the labor and cost for forming a microgap by a laser, the present applicant has previously described one of the methods as shown in FIG. Conductive film 91 reaching the plate surface from one edge to the other edge
Alumina substrate 91 (FIG. 13A) on which A is formed, and a groove 92B reaching from one edge to the other edge are formed on one plate surface, and the bottom surface of this groove 92B is conductive from one edge to the other edge. Alumina substrate 92 (FIG.
(B)) A chip composed of a combined body in which one plate surface is overlaid so that the conductive film 91A of the alumina substrate 91 and the groove 92B of the alumina substrate 92 face each other, and they are bonded together via the glass layer 93. The element body 94 (FIG. 13C),
Conductive glass layers 95A, 9 are provided on both end faces of (d)), respectively.
A chip type surge absorber having cap electrodes 96A and 96B mounted via 5B has been proposed (Japanese Patent Application No. 10-23).
No. 8878. Hereinafter, it is referred to as "first application". ).

The conductive glass layer 95A of this chip type surge absorber is positioned so as to contact the conductive film 91A and expose the conductive film 92A on one end face of the chip-shaped element 94, and the conductive glass layer 95A is exposed. 95B is located so as to expose the conductive film 91A and contact the conductive film 92A on the other end surface of the chip-shaped element 94, and the inside of the groove 92B is a filled gas atmosphere.
This chip type surge absorber has 91, 92
Edges of the conductive films 91A and 92A and the cap electrode 96
Since the gap d formed between A and 96B becomes a discharge gap, it is not necessary to form a microgap by laser.

[0010]

However, in this chip type surge absorber, the conductive glass layer 95A,
Since the variation in the thickness of 95B is relatively large, the variation in the gap d formed by this thickness is large. On the other hand, generally, as a characteristic of the microgap type surge absorber, the relationship between the P · d value (gas pressure × gap width) and Vs (DC discharge starting voltage) is that Vs decreases as the P · d value decreases. , At a certain P · d value, no more P
・ Vs stops decreasing even if the d value is decreased and remains constant. Therefore, the P · d value (“(P · d) _min ”) indicating the minimum value of Vs
Called. If the absorber is manufactured under a condition of less than 1), Vs is stable even if there is some variation in the gap d, that is, the thickness of the conductive glass layer for bonding, at a constant gas pressure. Therefore, when high gas pressure is applied, P ・ d>
Under the condition of (P · d) _min , the variation of the gap d has a great influence on the discharge starting voltage, and there is a problem that the performance is not stable. Further, when a metal brazing material is used for sealing, there is a problem that the conductive film on the alumina substrate is electrically connected and a gap cannot be formed.

The present invention solves the above-mentioned problems of the prior application and is a chip type surge absorber having a discharge chamber in a filled gas atmosphere, which prevents deviation of the overlapping condition of substrates and facilitates sealing. In addition, it can be manufactured easily and inexpensively by omitting the labor and cost for forming a microgap by a laser, and can be sealed with a metal braze and prevent the variation of the discharge gap. Another object of the present invention is to provide a chip type surge absorber that can provide a high voltage product with a stable discharge starting voltage.

[0012]

According to another aspect of the present invention, there is provided a chip type surge absorber, wherein a conductive film is formed on one plate surface of an insulating substrate from near one edge to near the other edge. A first substrate having a conductive film non-forming portion of a predetermined width provided near the other end edge, and a second substrate having a groove extending from one edge to the other edge on one plate surface of the insulating substrate. A chip-type surge absorber comprising a substrate and a cap electrode, wherein the first substrate and the second substrate are arranged so that the one plate surface faces each other such that the groove and the conductive film face each other. Are stacked and bonded via a glass layer, and the cap electrodes are attached to both end surfaces of a chip-shaped element made of a combined body of the first substrate and the second substrate via bonding layers, respectively. And the inside of the groove is filled with gas atmosphere. And wherein the Rukoto.

The tip type surge absorber of claim 2 is
A first conductive film is formed on one plate surface of the insulating substrate, the first conductive film extending from the vicinity of one end edge to the other end edge, and a conductive film non-forming portion having a predetermined width is provided near the one end edge. And a groove extending from one edge to the other edge are formed on one plate surface of the insulating substrate, and a second conductive film is formed on the bottom surface of the groove from the one edge to the vicinity of the other edge. And a second substrate having a conductive film non-forming portion of a predetermined width provided near the other end edge thereof, and a cap electrode, wherein the first substrate and the second substrate are provided. The substrate of 1 is overlapped with the one plate surface so that the groove and the first conductive film face each other, and is bonded through a glass layer, and the cap electrode is connected to the first substrate. Mounted on both end faces of the chip-shaped body composed of a combined body with the second substrate via bonding layers, respectively. Ri, and the interior of the groove, characterized in that it is a filler gas atmosphere.

In the case of such a chip type surge absorber of the present invention, the gap formed between the edge of the conductive film on the substrate and the cap electrode becomes the discharge gap. It is not necessary to form a microgap.

In addition, this discharge gap d is the sum of the conductive film non-formation portion of the predetermined width d ₁ on the substrate and the film thickness d ₂ of the bonding layer of the cap electrode on the end face of the chip-shaped element ( d
= D ₁ + d ₂ ), even if there is some variation in the film thickness d ₂ of this bonding layer, the variation in the discharge gap d can be made extremely small. Further, by providing the conductive film non-forming portion, the metal brazing can be used.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 is a sectional view showing an embodiment of the chip type surge absorber shown in FIGS.

In FIG. 1, reference numeral 1 is an alumina substrate which serves as a first insulating substrate, and a conductive film 2 is formed on one plate surface thereof. The conductive film 2 is formed from one edge 1A of the alumina substrate 1 to the vicinity of the other edge 1B, and a conductive film non-formation portion M is provided in the vicinity of the other edge 1B. Has been. Further, a discharge chamber forming groove 4 is formed on one plate surface of the alumina substrate 3 serving as the second insulating substrate so as to reach from one edge 3A of the alumina substrate 3 to the other edge 3B. Then, a conductive film 5 is formed on the bottom surface of the groove 4. This conductive film 5
Is formed from one end edge 3A of the alumina substrate 3 to the other end edge 3B, and a conductive film non-forming portion M is provided in the vicinity of the one end edge 3A.

The chip type surge absorber 10 shown in FIG.
The alumina substrate 1 and the alumina substrate 3 are stacked and integrated so that the conductive film 2 of the alumina substrate 1 faces the groove 4 of the alumina substrate 3 and are integrated on both end surfaces of the chip-shaped element body 6. The cap glass electrodes 8A, 8
B is joined. The interior of the groove 4 is filled with a gas atmosphere.

In this chip-type surge absorber 10, the total d of the width d ₁ of the conductive film non-formed portion M on the plate surfaces of the alumina substrates 1 and 3 and the film thickness d ₂ of the conductive glass layer 7 is the discharge gap. Function as and absorb the surge.

Next, this chip type surge absorber 10
The manufacturing procedure of will be described with reference to FIG.

First, a conductive film 2 is formed on one plate surface of an alumina substrate 1 which is a first insulating substrate (FIG. 5).
(A)). This conductive film 2 is formed from one edge 1A of the alumina substrate 1 to the vicinity of the other edge 1B, and a conductive film non-formation portion M is provided in the vicinity of the other edge 1B.

Separately, a glass layer G for joining the substrates to each other is formed on one plate surface of the alumina substrate 3 serving as the second insulating substrate.
After forming an adhesive layer such as, the groove 4 is formed, and the conductive film 5 is formed on the bottom surface of the groove 4. This conductive film 5 can be formed in the same manner as the above-mentioned conductive film 2, but in this alumina substrate 3, the conductive film 5 extends from the vicinity of one edge 3A to the other edge 3B. Then, the conductive film non-forming portion M is provided in the vicinity of the one edge 3A. (FIG.5 (b)).

Then, these alumina substrates 1 and 3 are stacked and heated so that the conductive film 2 and the groove 4 face each other, and the alumina substrate 1 and the alumina substrate 3 are bonded and integrated to form a chip-shaped element. The body 6 is obtained (FIG. 5 (c)).

Next, conductive glass layers for bonding cap electrodes are formed on both end faces of the chip-shaped body 6. In forming the conductive glass layer, first, the conducting electrode 7a is formed, and the glass layer 7b is formed thereon (FIG. 5).
(D)).

After that, cap electrodes are attached to both end faces of the chip-shaped element body 6, and the discharge chamber formed by the grooves 4 of the alumina substrate 3 is replaced with a sealing gas and fired (by this firing, The glass layer 7b is absorbed by the conducting electrode 7a to form the conductive glass layer 7.), and the cap electrode is bonded to the chip-shaped element body 6 and sealed to form the structure shown in FIG.
A chip type surge absorber 10 shown in is obtained.

In FIG. 2, reference numeral 1 is an alumina substrate serving as a first insulating substrate, and a conductive film 2 is formed on one plate surface. The conductive film 2 is formed from the vicinity of one edge 1A of the alumina substrate 1 to the vicinity of the other edge 1B, and in the vicinity of the both edges 1A and 1B,
Non-formed portions M, M of the conductive film are provided. Also,
A groove 4 for forming a discharge chamber is formed on one plate surface of the alumina substrate 3 serving as the second insulating substrate so as to extend from one edge 3A of the alumina substrate 3 to the other edge 3B. .

The chip type surge absorber 10A shown in FIG.
Is such an alumina substrate 1 and an alumina substrate 3,
The conductive film 2 of the alumina substrate 1 has the groove 4 of the alumina substrate 3
Chip-shaped element body 6 which is laminated and integrated so as to face with
Cap electrodes 8A and 8B are joined to both end faces of A by a conductive glass layer or an active metal solder 9. The interior of the groove 4 is filled with a gas atmosphere.

This chip type surge absorber 10A is
Width d of the non-formed portion M of the conductive film on the plate surface of the alumina substrate 1
The total d of ₁ and the film thickness d ₂ of the conductive glass layer 7 functions as a discharge gap to absorb the surge.

Next, this chip type surge absorber 10
The manufacturing procedure of A will be described with reference to FIG.

First, a conductive film 2 is formed on one plate surface of an alumina substrate 1 which is a first insulating substrate (FIG. 6).
(A)). This conductive film 2 is formed from the vicinity of one edge 1A of the alumina substrate 1 to the vicinity of the other edge 1B, and the conductive film non-formation portion M is formed in the vicinity of both edges 1A and 1B.
To provide.

Separately, a glass layer G for joining the substrates to each other is formed on one plate surface of the alumina substrate 3 serving as the second insulating substrate.
After forming the adhesive layers such as the above, the groove 4 is formed.

Then, these alumina substrates 1 and 3 are overlapped and heated so that the conductive film 2 and the groove 4 face each other, and the alumina substrate 1 and the alumina substrate 3 are bonded and integrated to form a chip-shaped element. A body 6A is obtained (FIG. 6 (c)).

Next, the active metal solder 9 for bonding the cap electrodes is applied to both end faces of the chip-shaped body 6 (or
A conductive glass layer may be formed as shown in FIG. ).

Then, cap electrodes are attached to both end surfaces of the chip-shaped element 6A, and the discharge chamber formed by the grooves 4 of the alumina substrate 3 is replaced with a sealing gas and fired to burn the cap electrodes into chips. The chip type surge absorber 10A shown in FIG.
To get

In FIG. 3, reference numeral 1 is an alumina substrate serving as a first insulating substrate, and a conductive film 2 is formed on one plate surface. The conductive film 2 is formed from one edge 1A of the alumina substrate 1 to the vicinity of the other edge 1B, and a conductive film non-formation portion M is provided in the vicinity of the other edge 1B. Has been. Further, a discharge chamber forming groove 4 is formed on one plate surface of the alumina substrate 3 serving as the second insulating substrate so as to reach from one edge 3A of the alumina substrate 3 to the other edge 3B. A conductive film 5 is formed on the bottom surface of the groove 4. This conductive film 5 is
The alumina substrate 3 is formed from the vicinity of one end edge 3A to the other end edge 3B, and a conductive film non-formation portion M is provided near the one end edge 3A.

Chip type surge absorber 10B of FIG.
Is such an alumina substrate 1 and an alumina substrate 3,
The conductive film 2 of the alumina substrate 1 has the groove 4 of the alumina substrate 3
Chip-shaped element body 6 which is laminated and integrated so as to face with
Cap electrodes 8A and 8B are bonded to both end surfaces of the alumina glass 1 by a conductive glass layer or an active metal braze 9, and one edge 1 of the alumina substrate 1 of the active metal braze 9 is joined.
The active metal solder 9A, 9D on the end face on the A side and the end face on the other edge 3B side of the alumina substrate 3 is formed so as to be electrically connected to the end portions of the conductive coatings 2, 5 formed on the respective substrates 1, 3. In addition, the active metal solders 9B and 9C on the other end edge 1B side end surface of the alumina substrate 1 and the one end edge 3A side end surface of the alumina substrate 3 are formed on the respective substrates 1 and 3. The ends of the films 2 and 5 are provided so as to be exposed at the end surface of the chip-shaped body 6. In this way, by forming the active metal solder as the bonding layer so as to recede from the plate surface on the conductive film forming side on the end surface of the alumina substrate, the life of the chip type surge absorber is provided by providing the gap depth. Can be extended. The interior of the groove 4 is filled with a gas atmosphere.

This chip type surge absorber 10B is
The total d of the width d ₁ of the non-formation portion M of the conductive film on the plate surfaces of the alumina substrates 1 and 3 and the film thickness d ₂ of the active metal braze 9 functions as a discharge gap to absorb the surge.

Next, this chip type surge absorber 10
The manufacturing procedure of B will be described with reference to FIG.

First, as shown in FIG. 5 (a), the non-formation portion M of the conductive film is provided on one plate surface of the alumina substrate 1 serving as the first insulating substrate to form the conductive film 2 thereon. Formed (FIG. 7A).

Separately, a glass layer G for bonding the substrates to each other is formed on one plate surface of the alumina substrate 3 serving as the second insulating substrate.
After forming an adhesive layer such as, the groove 4 is formed, and the conductive film 5 is formed on the bottom surface of the groove 4 (FIG. 7B). This groove 4
Also, the conductive film 5 can be formed in the same manner as in the method shown in FIG.

Then, these alumina substrates 1 and 3 are overlapped and heated so that the conductive film 2 and the groove 4 face each other, and the alumina substrate 1 and the alumina substrate 3 are joined and integrated to form a chip-shaped element. The body 6 is obtained (FIG. 7 (c)).

Next, a conductive glass layer for bonding a cap electrode or an active metal solder 9 is formed on both end faces of the chip-shaped body 6.

When forming the active metal braze 9, the other end surface of the conductive film 2 of the alumina substrate 1 and one end surface of the conductive film 5 of the alumina substrate 3 are exposed at the end surface of the chip-shaped body 6. The active metal wax 9 is printed on.
Thereafter, cap electrodes are attached to both end surfaces of the chip-shaped element body 6, and the discharge chamber formed by the grooves 4 of the alumina substrate 3 is replaced with a sealing gas and fired, so that the cap electrode is formed. The chip type surge absorber 10B shown in FIG.

In FIG. 4, reference numeral 1 is an alumina substrate which serves as a first insulating substrate, and a conductive film 2 is formed on one plate surface thereof. The conductive film 2 is formed from one edge 1A of the alumina substrate 1 to the vicinity of the other edge 1B, and the notches R and R are formed at both edges 1A and 1B. In the vicinity of the edges 1A and 1B,
The non-formed portions M, M of the alumina substrate 1 are provided. Further, a discharge chamber forming groove 4 is formed on one plate surface of the alumina substrate 3 serving as the second insulating substrate so as to reach from one edge 3A of the alumina substrate 3 to the other edge 3B. ing.

Chip type surge absorber 10C shown in FIG.
Is such an alumina substrate 1 and an alumina substrate 3,
The conductive film 2 of the alumina substrate 1 has the groove 4 of the alumina substrate 3
Chip-shaped element body 6 which is laminated and integrated so as to face with
Cap electrodes 8A and 8B are bonded to both end faces of B by a conductive glass layer or an active metal solder 9. The interior of the groove 4 is filled with a gas atmosphere.

This chip type surge absorber 10C is
Width d of the non-formed portion M of the conductive film on the plate surface of the alumina substrate 1
The total d of ₁ and the film thickness d ₂ of the active metal braze 9 functions as a discharge gap to absorb the surge.

Next, this chip type surge absorber 10
The procedure for producing C will be described with reference to FIG.

First, a conductive film 2 is formed on one plate surface of an alumina substrate 1 which is a first insulating substrate. The conductive film 2 is formed so as to extend from one edge 1A of the alumina substrate 1 or its vicinity to the other edge 1B or its vicinity. After forming the conductive film 2, the alumina substrate 1 is formed to form the non-formed portion M of the conductive film.
A part of both end edges 1A, 1B is cut shallowly and obliquely to form a cutout portion R (FIG. 8A).

Separately, a glass layer G for joining the substrates to each other is formed on one plate surface of the alumina substrate 3 serving as the second insulating substrate.
After forming the adhesive layers such as the above, the groove 4 is formed (see FIG.
(B)).

Then, these alumina substrates 1 and 3 are superposed so that the conductive film 2 and the groove 4 face each other and heated, whereby the alumina substrate 1 and the alumina substrate 3 are bonded and integrated to form a chip-shaped element. A body 6B is obtained (FIG. 8 (c)).

Next, the active metal solder 9 for bonding the cap electrodes is applied to both end faces of the chip-shaped element 6B (or, as shown in FIG. 5D, the conductive glass layer 2 is also formed. good.).

Then, cap electrodes are attached to both end faces of the chip-shaped element 6B, and the discharge chamber formed by the grooves 4 of the alumina substrate 3 is replaced with a sealing gas and fired to burn the cap electrodes into chips. A chip type surge absorber 10C shown in FIG. 4 which is joined to the element body 6B and sealed.
To get

In the present invention, the insulating substrate is not limited as long as it is insulating and highly airtight, and in addition to the alumina substrate, ceramics such as corundum, mullite, corundum mullite, acryl and bakelite, plastic or resin. A substrate can be used. Normally,
A substrate having a thickness of about 0.3 to 1.0 mm is used as this substrate.

Conductive film on first insulating substrate and second
The conductive film on the bottom surface of the groove of the insulating substrate is made of Ti, TiN,
TiO, Ta, W, SiC, SnO ₂ , Ta ₂ O ₅ , Cr ₂
O ₃ , RuO ₂ , ITO, BaAl, Nb, Si, C, A
u, Ag, Ag-Pt, Pt, Pd, Ag-Pd, La
Alternatively, it is preferable to form a mixture of two or more of these with a film thickness of about 0.1 to 20 μm by a sputtering method, a vapor deposition method, an ion plating method, a printing method, a baking method, or the like.

Further, it is preferable that the width of the conductive film on the first insulating substrate is approximately the same as the width of the groove of the second insulating substrate. The non-formed part M of the conductive film can be formed by providing a part where the film is not deposited, and the width d ₁ of the non-formed part M of the conductive film is preferably about ₁ to 500 μm. .

The depth of the groove of the second insulating substrate is preferably about 1/3 to 2/3 of the thickness of the insulating substrate, and its width is 1/3 of the width of the insulating substrate. It is preferably about 1/2. Specifically, the groove depth is 0.2 to 0.4 m.
m, and the width of the groove is preferably about 0.5 to 1 mm.

The chip type surge absorber 10 shown in FIG.
The notch R of C can be formed by laser cutting or dicing, and the width of the notch R is ₁ to 5 equivalent to the width d ₁ of the non-formed portion M of the conductive film.
00 μm is preferable, and the depth of the deepest part (s in FIG. 4) is 1 to
The thickness is preferably about 100 μm, specifically about 30 μm, for example.

Further, in the present invention, the film thickness d of the conductive glass layer or the active metal brazing layer as the bonding layer of the cap electrode.
₂ is preferably 1 to 100 μm, and the total of the width d ₁ of the non-formed portion M of the conductive film is 1 to 100 μm.
It is preferable to form a discharge gap of m.

Further, as shown in FIG. 3, an active metal wax or a conductive glass layer as a bonding layer is formed on the end face of the alumina substrate on the side where the conductive film is not formed M on the conductive film forming side of the alumina substrate. When it is formed by retreating from the plate surface,
The receding width (t in FIG. 3) is preferably about 1 to 100 μm, specifically about 30 μm, for example.

When a conductive glass layer is formed as the bonding layer, a glass electrode is formed after forming conductive electrodes of Ag, Ag-Pt, Ag-Pd, etc., and then degreasing and calcination are performed. . When an active metal solder is used as the bonding layer, Ti can be used as the active metal solder, and in this case, degreasing and calcination are unnecessary.

As the filling gas, He, N ₂ , Ar, N
_{e, Xe, SF 6, CO} 2, H 2, C 2 F 6, C 3 F 8, CF 4
Etc. can be used alone or in admixture of two or more. The pressure of the enclosed gas is usually about 100 to 1000 Torr.

[0063]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below.

In the following examples, the conductive coatings 2 and 5 were formed by printing or sputtering, and the non-forming portion M of the conductive coating was formed by providing a portion that was not printed or sputtered. The cutout R of the alumina substrate was formed by laser cutting.

Example 1 A chip type surge absorber 10 shown in FIG. 1 was manufactured.

Two alumina substrates 1 and 3 having a thickness of 3.2 mm × 1.6 mm × 0.5 mm were prepared, and one of the alumina substrates 1 was made of an Ag film having a width of 0.5 mm and a length of 3.12 mm. Of the conductive film 2 is formed, and the non-formed portion M of the conductive film is d.
₁ = 80 μm in width. Further, after the glass paste is printed on the plate surface of the other alumina substrate 3, degreased and calcined to form the glass layer G, the width is 0.5 mm and the depth is 0.25 m.
The groove 4 of m was formed, the non-formation part M of the conductive film having a width d ₁ = 80 μm was provided on the bottom surface of the groove 4, and the conductive film 5 made of an Ag film was formed. Then, the alumina substrates 1 and 3 were overlapped and heated so that the conductive film 2 and the groove 4 faced each other, and bonded and integrated to obtain a chip-shaped element body 6. After forming Ag films on both end faces of this chip-shaped element body 6, a glass paste was printed, degreased and calcined to form a glass layer. Next, the cap electrodes 8A and 8B are attached to both ends of the chip-shaped element body 6 on which the glass layer is formed, the inside of the groove 4 is replaced with Ar (760 torr), and the cap electrodes 8A and 8B are joined by high temperature firing. It was sealed together with it to obtain a chip type surge absorber 10. The thickness d ₂ of the conductive glass layer 7 as the bonding layer is 20 μm,
The total discharge gap d with the width d ₁ of the non-formed portion M of the conductive film
Was 100 μm.

With respect to the obtained chip type surge absorber, the direct current discharge starting voltage (Vs) (the voltage at the time when the discharge current became 1 mA when the DC voltage was applied) was examined, and the results are shown in Table 1.
It was shown to.

This chip type surge absorber did not require laser processing for the microgap, and could be manufactured easily and at low cost. Also, there was no problem of substrate displacement.

Example 2 A chip type surge absorber 10A shown in FIG. 2 was manufactured.

Two alumina substrates 1 and 3 having a thickness of 3.2 mm × 1.6 mm × 0.5 mm are prepared, and one of the alumina substrates 1 is made of a conductive Ag film having a width of 0.5 mm and a length of 3.04 mm. The conductive film 2 was formed, and the conductive film non-formation portions M, M were provided on both ends thereof in a width of d ₁ = 80 μm. Further, a glass paste is printed on the plate surface of the other alumina substrate 3, degreased and calcined to form a glass layer G, and then a width of 0.5 mm,
The groove 4 having a depth of 0.25 mm was formed. Then, the alumina substrates 1 and 3 were overlapped and heated so that the conductive film 2 and the groove 4 faced each other, and bonded and integrated to obtain a chip-shaped element body 6A. T on both end surfaces of this chip-shaped body 6A
i active metal braze 9 is applied, and then cap electrode 8
By mounting A and 8B on both ends of the chip-shaped element 6A, substituting the inside of the groove 4 with Ar (760 torr) and baking at a high temperature, the cap electrodes 8A and 8B are joined and sealed, and a chip type surge is provided. The absorber 10A was obtained. The thickness d ₂ of the active metal braze 9 as the bonding layer is 20 μm,
The total discharge gap d with the width d ₁ of the non-formed portion M of the conductive film
Was 100 μm.

With respect to the obtained chip type surge absorber, the DC discharge starting voltage (Vs) was examined in the same manner as in Example 1, and the results are shown in Table 1.

This chip type surge absorber did not require laser processing for the microgap and could be manufactured easily and at low cost. Also, there was no problem of substrate displacement.

[Example 3] A chip type surge absorber 10B shown in Fig. 3 was manufactured.

Two alumina substrates 1 and 3 each having a thickness of 3.2 mm × 1.6 mm × 0.5 mm were prepared, and one of the alumina substrates 1 was made of Ag film having a width of 0.5 mm and a length of 3.12 mm. Of the conductive film 2 is formed, and the non-formed portion M of the conductive film is d.
₁ = 80 μm in width. Further, after the glass paste is printed on the plate surface of the other alumina substrate 3, degreased and calcined to form the glass layer G, the width is 0.5 mm and the depth is 0.25 m.
A groove 4 of m was formed, a non-formation portion M of the conductive film having a width d ₁ = 80 μm was provided on the bottom surface of the groove 4, and a conductive film 5 made of an Ag film was formed. Then, the alumina substrates 1 and 3 were overlapped and heated so that the conductive film 2 and the groove 4 faced each other, and bonded and integrated to obtain a chip-shaped element body 6.
Ti active metal braze 9 was applied to both end faces of the chip-shaped body 6. When applying the active metal braze 9, the active metal braze 9 is t = 30 μm from the plate surface of the alumina substrate on which the electroconductive film is not formed, on the end face of the alumina substrate on the side where the electroconductive film is not formed. It was formed by retreating. Next, the cap electrodes 8A and 8B are attached to both ends of the chip-shaped element body 6 on which the glass layer is formed, and the inside of the groove 4 is filled with Ar (760t).
(orr) and baked at high temperature to bond and seal the cap electrodes 8A and 8B to obtain a chip type surge absorber 10B. The film thickness d ₂ of the active metal braze 9 as the bonding layer was 20 μm, and the total discharge gap d with the width d ₁ of the non-formed portion M of the conductive film was 100 μm.

With respect to the obtained chip type surge absorber, the DC discharge starting voltage (Vs) was examined in the same manner as in Example 1, and the results are shown in Table 1.

This chip type surge absorber did not require laser processing for the microgap, and could be manufactured easily and at low cost. Also, there was no problem of substrate displacement.

Example 4 A chip type surge absorber 10C shown in FIG. 4 was manufactured.

Two alumina substrates 1 and 3 having a thickness of 3.2 mm × 1.6 mm × 0.5 mm were prepared, and one of the alumina substrates 1 was made of a conductive Ag film having a width of 0.5 mm and a length of 3.2 mm. Forming a protective film 2 and cutting out both ends thereof to form a cutout R,
By forming R, the non-formation portions M, M of the conductive film were provided in a width of d ₁ = 80 μm. Further, a glass paste is printed on the plate surface of the other alumina substrate 3, degreased and calcined to form a glass layer G, and then the width is 0.5 mm and the depth is 0.25.
The groove 4 of mm was formed. The notch R was formed so that the depth s of the deepest part was s = 30 μm. Then, the conductive film 2 and the groove 4
By stacking and heating the alumina substrates 1 and 3 so that and face each other, the chips are joined together to form a chip-shaped element body 6B.
Got Ti active metal braze 9 is applied to both end surfaces of the chip-shaped body 6B, cap electrodes 8A and 8B are attached to both ends of the chip-shaped body 6B, and the inside of the groove 4 is filled with Ar (760).
The cap electrodes 8A and 8B were joined and sealed by substituting with (torr) and baking at a high temperature to obtain a chip type surge absorber 10C. The thickness d ₂ of the active metal braze 9 as the bonding layer is 20 μm, and the total discharge gap d with the width d ₁ of the non-formed portion M of the conductive film is 100 μm.
Met.

With respect to the obtained chip type surge absorber, the DC discharge starting voltage (Vs) was examined in the same manner as in Example 1, and the results are shown in Table 1.

This chip type surge absorber did not require laser processing for the microgap and could be manufactured easily and at low cost. Also, there was no problem of substrate displacement.

[Comparative Example 1] A chip type surge absorber shown in FIG. 12 was manufactured.

Two alumina substrates 81 and 82 having a thickness of 3.2 mm × 1.6 mm × 0.5 mm were prepared, and a discharge electrode 81A made of an Ag film and having a width of 0.5 mm was provided on the plate surface of one alumina substrate 81. , 81B with a discharge gap having a width of 20 μm. Further, a groove 82A having a width of 0.5 mm and a depth of 0.25 mm was formed on the plate surface of the other alumina substrate 82, and both alumina substrates 81 and 82 were joined. Then, the conductive layer 8
5, the glass layer 86 is formed, and the cap electrode 8 is formed.
4A and 84B are mounted, and the inside of the groove 82A is Ar (760to
rr) and then baked to replace the cap electrode 84.
A and 84B were joined and sealed.

The surge absorber thus obtained was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Although this chip type surge absorber does not have a problem of the displacement of the substrate, it requires much labor and cost due to the laser processing for forming the microgap.

Comparative Example 2 A chip type surge absorber shown in FIG. 13 was manufactured.

Two alumina substrates 91 and 92 having a thickness of 3.2 mm × 1.6 mm × 0.5 mm are prepared, and one of the alumina substrates 91 is made of a conductive Ag film having a width of 0.5 mm and a length of 3.2 mm. The conductive film 91A was formed. Further, a glass paste is printed on the plate surface of the other alumina substrate 92 to degrease it,
After calcination to form the glass layer 93, a groove 92B having a width of 0.5 mm and a depth of 0.25 mm was formed, and a conductive film 92A made of Ag was formed on the bottom surface of the groove 92B. Then, the alumina substrates 91 and 92 were overlapped and heated so that the conductive film 91A and the groove 92B face each other, and joined and integrated to obtain a chip-shaped element body 94. After forming an Ag-Pt conductive film on both end surfaces of the chip-shaped element body 94 so as not to cover one exposed part of the conductive films 91A and 92A, a glass paste is printed thereon to degrease and calcine. Then, the conductive glass layers 95A and 95B having a thickness d = 20 μm (discharge gap 20 μm) were formed. Next, the cap electrodes 96A and 96B are attached to both ends of the chip-shaped element 94, the inside of the groove 92B is replaced with Ar (760 torr), and the cap electrodes 96A and 96B are joined and sealed by high temperature firing. I got a chip type surge absorber.

With respect to the obtained chip type surge absorber, the DC discharge starting voltage (Vs) was examined in the same manner as in Example 1, and the results are shown in Table 2.

This chip type surge absorber did not require laser processing for the microgap, and could be manufactured easily and at low cost. Also, there was no problem of substrate displacement.

Comparative Example 3 The chip type surge absorber shown in FIG. 9 was manufactured.

Three alumina substrates 51, 52, 53 having a thickness of 3.2 mm × 1.6 mm × 0.5 mm were prepared, and a discharge gap having a width of 20 μm was provided on the alumina substrate 51 to form a pair of Ag films. Discharge electrodes 51A and 51B are formed. Further, an opening 52A having a diameter of 1 mm was formed in the alumina substrate 52. Then, the three alumina substrates 51, 52, 53
Is heat-bonded with glass paste and Ar (760T
orr) was enclosed, and terminal electrodes 55A and 55B were further formed.

The obtained chip type surge absorber was evaluated in the same manner as in Example 1 and the results are shown in Table 2.

This chip type surge absorber requires much labor and cost because of laser processing for forming the microgap. Further, since the three substrates are laminated and bonded, the displacement of the substrates was large.

[0093]

[Table 1]

As is clear from Table 1, according to the present invention, a chip having the same performance as a normal microgap type surge absorber can be easily formed at low cost without forming a microgap by laser processing. Type surge absorber can be realized. Moreover,
Since the variation in the discharge gap is small, it is possible to manufacture a high-voltage product with a stable discharge starting voltage.

[0095]

As described above in detail, the chip-type surge absorber of the present invention is a chip-type surge absorber having a discharge chamber in a sealed gas atmosphere, and prevents the substrates from overlapping and is easily sealed. In addition, it is possible to perform the manufacturing process easily and at a low cost by omitting the labor and cost for forming the microgap by the laser. In addition, it is possible to seal with metal brazing, and it is possible to prevent variations in the discharge gap and provide a high-voltage-compatible product with a stable discharge starting voltage.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a chip type surge absorber of the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the chip type surge absorber of the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of the chip type surge absorber of the present invention.

FIG. 4 is a sectional view showing another embodiment of the chip type surge absorber of the present invention.

5 (a), 5 (b), and 5 (c) are perspective views and FIG. 5 (d) is a cross-sectional view, illustrating a procedure for manufacturing the chip type surge absorber of FIG.

6A and 6B are views for explaining a manufacturing procedure of the chip type surge absorber shown in FIG. 2, wherein FIGS. 6A, 6B and 6C are perspective views and FIG.

7A and 7B are views for explaining a manufacturing procedure of the chip type surge absorber of FIG. 3, wherein FIGS. 7A, 7B and 7C are perspective views and FIG. 7D is a sectional view.

8A and 8B are views for explaining a manufacturing procedure of the chip type surge absorber shown in FIG. 4, in which FIGS. 8A, 8B and 8C are perspective views and FIG. 8D is a sectional view.

FIG. 9 is a perspective view showing a surge absorber according to a prior art.

FIG. 10 is a perspective view showing a surge absorber according to a prior art.

FIG. 11 is a perspective view showing a surge absorber according to a prior art.

FIG. 12 is a diagram showing a surge absorber according to a prior art, in which (a) is a perspective view and (b) and (c) are sectional views.

FIG. 13 is a view showing a surge absorber according to the prior application, in which (a), (b), and (c) are perspective views, (d),
(E) Drawing is sectional drawing.

[Explanation of symbols]

1, 3 Alumina substrate 2, 5 Conductive film 4 Grooves 6, 6A, 6B Chip-shaped element 7 Conductive glass layers 8A, 8B Cap electrode 9 Active metal braze G Glass layer M Conductive film non-forming part R Notch 10,10A, 10B, 10C Chip type surge absorber

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koichiro Harada 2270 Yokose, Yokose-cho, Chichibu-gun, Saitama Mitsubishi Materials Corporation Electronic Technology Research Laboratory (72) Yoshiyuki Tanaka 2270 Yokose, Yokose-cho, Chichibu-gun, Saitama Mitsubishi Materials Co., Ltd. Electronic Technology Research Laboratory (72) Inventor Yasuhiro Sato 2270 Yokose, Yokose-cho, Chichibu-gun, Saitama Mitsubishi Materials Corporation Electronic Technology Research Laboratory (56) Reference JP-A-9-190868 (JP, A) Special Kaihei 3-230487 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01T 4/12 H05K 1/18

Claims (2)

(57) [Claims] 1. A conductive coating film is formed on one plate surface of an insulating substrate, the conductive coating film extending from the vicinity of one end edge to the vicinity of the other end edge, and a conductive coating film non-forming portion having a predetermined width near the one end edge and the other end edge. A chip type surge absorber comprising: a first substrate on which is provided a second substrate in which a groove extending from one edge to the other edge is formed on one plate surface of an insulating substrate; and a cap electrode. The first substrate and the second substrate are bonded together via a glass layer such that the one plate surface is overlaid so that the groove and the conductive film face each other, The cap electrodes are attached to both end faces of a chip-shaped element made of a combined body of the first substrate and the second substrate via bonding layers, respectively, and the inside of the groove is filled with a sealed gas atmosphere. Chip type surge absorber. 2. A first conductive film extending from the vicinity of one edge to the other edge is formed on one plate surface of the insulating substrate,
A first substrate having a conductive film non-forming portion of a predetermined width provided near the one edge, and a groove extending from one edge to the other edge is formed on one plate surface of the insulating substrate, and the bottom surface of the groove A second substrate on which a second conductive film extending from the one edge to the vicinity of the other edge is formed, and a conductive film non-forming portion having a predetermined width is provided near the other edge; A chip-type surge absorber comprising: a glass substrate, wherein the first substrate and the second substrate are laminated on each other so that the groove and the first conductive film face each other. And the cap electrodes are attached to both end surfaces of a chip-shaped element made of a combined body of the first substrate and the second substrate via bonding layers, respectively, and A chip type surge absorber in which the inside of the groove is filled with a gas atmosphere.