JPH08288049A - Surge absorber - Google Patents

Abstract

PURPOSE: To stabilize discharge voltage and response speed, regarding a surge absorber for protecting an electronic circuit or an electronic part against a surge. CONSTITUTION: A glass sealed body 22 is internally provided with a flat chip substrate 23, and resistor layers 24a and 24b of high resistance are formed on the substrate 23. Also, both ends of the substrate 23 are fitted with main electrodes 25a and 25b electrically continuous to the layers 24a and 24b. Projections 37a and 37b from both layers 24a and 24b face each other in a gap 37. When a surge is applied to lead wires 26a and 26b, discharge first takes place across the projections 37a and 37b, and, then, propagates to a gap between the main electrodes 25a and 25b. According to this construction, a discharge start position is limited to an area across the projections 37a and 37b. Thus, when the shape of the projections 37a and 37b and the gap thereof are precisely established, discharge voltage and response speed can be defined with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surge absorber for protecting an electronic circuit or an electronic component from a surge, which can exhibit a particularly stable surge absorbing function and can improve the life of a resistor layer. Regarding absorbers.

[0002]

2. Description of the Related Art FIG. 7 is a perspective view showing the structure of a conventional gap type surge absorber, and FIG. 8 is an enlarged sectional view showing an enlarged gap portion of the surge absorber. This surge absorber 1 is provided with a round bar-shaped base body 3 formed of alumina (aluminum oxide; Al ₂ O ₃ ) or the like inside a glass sealing body 2, and the surface of the base body 3 is
Resistor layers 4a and 4b facing each other through the gap 7 are formed. The resistor layers 4a and 4b are made of tin oxide (Sn
It is made of a high resistance material such as O ₂ ). The gap 7 is formed in a straight line along the entire circumference of the base body 3, and in the entire length of the gap 7, both resistor layers 4 are formed.
The distance between a and 4b is constant. In FIG. 8, the gap (gap length) of the gap 7 is indicated by G.

Main electrodes 5a and 5b, which are electrically connected to the respective resistor layers 4a and 4b, are provided at both ends of the substrate 3. The main electrodes 5a and 5b are formed in a cap shape from a metal material having a low resistance value, and are fitted to both ends of the base 3 from above the resistor layers 4a and 4b. Both main electrodes 5
Lead wires 6a and 6b are connected to a and 5b, and the lead wires 6a and 6b extend to the outside of the glass sealing body 2.
The inside of the glass sealing body 2 is set to a pressure of about 100 to 500 Torr, and this inside is filled with an inert gas such as argon (Ar), helium (He), or neon (Ne).

In this conventional surge absorber, a resistor layer having a thickness of about 20 μm is formed on the entire outer surface of the round rod-shaped base body 3, and a resistance is applied along the circumference at the central portion of the base body 3 by laser processing. The gap 7 is formed by removing the body layer. Due to the limitation of processing accuracy of laser processing, the gap interval G is about several tens of μm, and the actual gap is about 30 μm with the minimum gap length.

An equivalent circuit for explaining the operation of the surge absorber can be represented as shown in FIG. 9, for example. In FIG. 9, R0 and R0 are the respective resistor layers 4
Resistance values of a and 4b, Ra is the resistance layer 4a in the gap 7
, 4b is an insulation resistance between the resistor layers 4a and 4b, and Rb is a discharge resistance when a discharge is started between the resistor layers 4a and 4b.
It is about 1 to 0.1Ω. C is the capacitance of the gap 7. In the state where the surge is not applied between the main electrodes 5a and 5b, the discharge is not performed in the gap 7, therefore the switch S2 represented by the equivalent circuit is connected to the insulation resistance Ra side, and the surge absorber is very It has a high electric resistance.

When a surge is applied between the main electrodes 5a and 5b, the switch S1 represented by the equivalent circuit is closed, and the gap 7 starts to be charged through the resistor R0 of the resistor layer. The discharge starting voltage in the gap 7 (capacity C) is determined by the gap length G, the gas pressure in the glass sealing body 2, and the like. When the charging voltage at the capacity C reaches the discharge starting voltage (Paschen's minimum voltage), the resistor layers 4a and 4b.
The discharge is started in the meantime. In the equivalent circuit of FIG. 9, the switch S2 is switched to the discharge resistor Rb by the information α when the charge voltage of the gap 7 reaches the discharge start voltage. The discharge in the gap 7 is a positive discharge or a negative discharge, the discharge moves on the surfaces of the resistor layers 4a and 4b, and finally the main electrodes 5a and 5b are bridged by an arc. In the final state where the main electrodes 5a and 5b are bridged by an arc due to discharge, the equivalent circuit is the main electrodes 5a and 5b.
It can be expressed that the space is connected only by the discharge resistance (the resistance lower than the resistance value R0 of the resistor layers 4a and 4b).

[0007]

The surge absorber 1 having the above-mentioned conventional structure has the following problems. (1) As shown in FIG. 7, the gap 7 extends linearly along the circumference of the base body 3. Therefore, the circumferential length of the gap 7, that is, the length at which the two resistor layers 4a and 4b face each other is a limited length determined by the diameter of the base body 3. Here, FIG. 10 is an enlarged view of the gap 7 of the conventional surge absorber 1, but in the conventional surge absorber 1, a resistor layer formed of tin oxide (SnO ₂ ) or the like is used as a laser. The gap is formed by processing. The processing accuracy in laser processing is not very high, and the resistor layers 4a and 4 facing each other with the gap 7 interposed therebetween are not used.
The facing edge portion of b is not linearly formed with high precision, but becomes a fine uneven shape. In the equivalent circuit shown in FIG. 9, when the voltage charged in the capacitance C of the gap 7 reaches the discharge start voltage, discharge is started between the resistor layers 4a and 4b.
The part where the discharge starts is the part where the gap between the resistor layers is narrow as shown in (a) or (b) in FIG. 10. The discharge in the part (b) or the part (b) triggers the discharge to the other part of the gap 7 and further to the space between the main electrodes 5
The discharge develops between a and 5b.

As described above, in the gap 7, when the surge is applied, the lines of electric force are concentrated on an unspecified portion shown by (a) and (b), and the discharge is first generated at this concentrated portion. . Therefore, the resistor layers 4a and 4b are damaged at the portion where the discharge is first generated, and the gap distance G is widened at this portion, and the resistor layers 4a and 4b do not substantially function as the gap when the surge is applied next. As described above, the resistor layer is damaged at different portions each time a surge is applied. In the conventional surge absorber 1, however, the gap 7 is linear and its length is a circle of the base body 3. Since the length is limited to the circumferential distance, the resistor layer is damaged over almost the entire length of the gap by applying the surge several times, and the life is shortened.

(2) Further, in the surge absorber, discharge is generated by triggering one of the facing portions (portions (a) and (b)) in the gap, and this discharge extends over the entire length of the gap 7. However, in the conventional surge absorber 1, as described above, the dimension of the gap 7 in the circumferential direction is short,
The area where the two resistor layers 4a and 4b face each other via the gap 7 is small. Therefore, when the discharge is performed between the resistor layers 4a and 4b in the entire gap 7, the discharge current becomes small, and during the discharge in the gap 7, that is, the initial discharge in the entire surge absorber 1,
The surge absorption energy is small.

(3) In the surge absorber, the resistor layer 4
The interval G between a and 4b affects the response speed and the discharge start voltage. If the gap G of the gap 7 is short, the response time from the application of the surge to the start of the discharge becomes fast,
If the interval G is long, the response time becomes slow. When the gap G of the gap 7 is short, the discharge start voltage is low, and when the gap G is long, the discharge start voltage is high. Therefore, for example, when constructing a surge absorber having a high discharge start voltage and a high response speed, multiple gaps 7 are provided at a predetermined pitch in the axial direction of the base 3 of the surge absorber, and the gaps between the gaps 7 are arranged. It is necessary to form G as short as possible.

In this way, the resistor layer 4a in the gap 7 is formed.
The distance G between the terminals 4 and 4b has a great influence on the performance and characteristics of the surge absorber. Therefore, in order to operate the surge absorber at the response speed and the discharge start voltage as designed, the distance G is faithful to the design. It is necessary to manufacture to match.

However, as shown in FIG. 10, in the gap 7 formed by the conventional laser processing, the shapes of the opposing edges of the resistor layers 4a and 4b located on both sides of the gap 7 are highly precise straight lines. However, in the gap 7, the facing distance between the resistor layers 4a and 4b varies at individual positions,
It is difficult to control the gap G of the gap 7 substantially. That is, when the opposing edges of both resistor layers 4a and 4b facing each other at the gap 7 are designed to be straight lines parallel to each other, at which position the gap interval G becomes substantially narrower. Alternatively, whether the width becomes wider is unspecified depending on variations in laser processing of individual products.

Therefore, as shown in (a) and (b) of FIG. 10, when the resistor layer is formed with a fine protrusion projecting in the direction of the gap 7, the interval of this portion is set. Since the response speed and the discharge start voltage are determined, the discharge start voltage may be lower than the designed value. On the other hand, if the gap G between the resistor layers is wider than the design value over the entire length of the gap 7, the response speed becomes significantly slower than the design value.

As described above, when a surge absorber having a high response speed and a high discharge starting voltage is set, it is manufactured with multiple gaps. However, the discharge starting voltage varies among the individual gaps. When the value becomes large, even if multiple gaps are provided in multiple, the discharge start voltage proportional to the number of gaps cannot be set, and the variation of the discharge start voltage of each gap is accumulated by the number of gaps. It becomes a big surge absorber.

The present invention has been made to solve the above-mentioned conventional problems. The substantial length dimension of the gap is increased so that the resistor layer can withstand repeated surges, thereby improving the life and the resistance. The purpose is to increase the current during discharge between body layers to increase the surge energy that can be absorbed during initial discharge.

Further, according to the present invention, the position where the discharge can be started first is specified between the resistor layers, and the substantial gap interval G is set with high precision by the shape of the resistor layer at that position. The purpose is to enable the response speed and the discharge start voltage to be set stably.

[0017]

According to a first aspect of the present invention, there is provided a resistor layer formed on the surface of a substrate, and main electrodes arranged on both sides of the resistor layer, wherein the resistor layer is A surge absorber in which three or more gaps are formed, wherein the gap has a shape in which irregularities are continuous in a direction in which the main electrodes face each other, and the resistor layers face each other at regular intervals along the entire length of the gap. It is characterized by doing.

That is, the gap extends in the circumferential direction for a columnar substrate and in the width direction for a flat substrate, but the gap undulates in the circumferential direction or the width direction. The shape is a triangular shape, a triangular wave shape, or a comb shape. Therefore, the opposing edge portions of both resistor layers sandwiching the gap are shaped so as to alternately enter in the direction of the opposing resistor layer.

A second aspect of the present invention has a resistor layer formed on the surface of a substrate and main electrodes arranged on both sides of the resistor layer, and one or more gaps are formed in the resistor layer. In the above-mentioned surge absorber, the resistor layers are opposed to each other at a constant interval in the gap, and protrusions projecting into the gap are formed in the resistor layer.

In the above, the protrusions are formed on the resistor layers on both sides facing each other across the gap, and the edge portions of the protrusions protruding from both resistor layers face each other in the gap. It is preferable that the protrusion having the edge portion has a substantially triangular shape.

Further, it is more preferable that the protrusions are provided at a plurality of places in the gap.

[0022]

In the first aspect of the present invention, the gap has a shape in which irregularities are repeated in the direction of both main electrodes, and the substantial length dimension of the gap is large. In other words, the length of the gap can be set to a length equal to or larger than the above dimension within a limited dimension in the circumferential direction of the columnar substrate and the widthwise direction of the flat substrate. The resistor layer is damaged at the portion where the discharge is first started when the surge is applied, that is, the portion which triggers the discharge, and this damaged portion does not become the discharge start position at the next surge application. Every time a surge is applied, any part of the resistor layer is damaged, but since the gap is substantially long, even if the number of positions to be damaged increases, the other intact gap part Will remain for a long time, and the life as a surge absorber can be extended. Further, since the gap can be lengthened even if the base body is small, a small-sized and long-life surge absorber can be configured.

Further, any position within the gap triggers, and after that, discharge between the resistor layers is started in the entire gap. However, the gap is long and the facing area of the resistor layers facing each other in the gap portion. Is getting larger,
The discharge current amount between the resistor layers increases, and the ability to absorb the energy of the surge increases.

In the second aspect of the present invention, the resistor layers face each other at a constant interval in the gap, and the resistor layer is provided with a protrusion protruding inward of the gap. Preferably, the protrusion is formed in both resistor layers. The protrusions are formed so that the protrusions face each other at the edge portions. In this case, the position where the discharge is started is limited to the protrusion portion. Therefore, unlike the structure shown in FIG. 10 in which it is not possible to specify which position is the first discharge position, it is possible to set a specific position in the gap as the discharge start point. Therefore, if the shape of this protrusion and the dimension of the opposing layer between the resistor layers in the portion where the protrusion is formed are determined with high accuracy,
With this size, it becomes easy to set the discharge start voltage and the response speed to values close to the design values. If the dimensions of the protrusions and the spacing of the resistor layers at the protrusions are set with high accuracy, even if the precision of the spacing of the edges of the resistor layer at the portions other than the protrusions drops, or Even if the edges of the resistor layer are not parallel to each other, or even if the edges of the resistor layer are slightly uneven, the response speed and the discharge start voltage of the surge absorber as a whole can be set with high accuracy. In particular, when the shape of the gap portion is set by the etching process, the shape of the protrusion and the interval between the resistor layers in the protrusion portion can be set with high accuracy.

In particular, when the protrusion is formed in a triangular shape having an edge portion, an electric field can be concentrated on this edge portion when a surge is applied, and the response speed and the discharge starting voltage according to the interval of the resistor layer at the protrusion portion are highly accurate. Can be set to. Further, when the electric discharge is started at the protrusion portion, the edge portion of the protrusion may be damaged. Therefore, if the protrusions are provided at multiple locations, even if any of the protrusions is damaged, the other protrusions can respond to the next surge application,
The life will be extended.

By providing the above-mentioned protrusions, it is possible to reduce variations in discharge start voltage and response speed. Therefore, when configuring a surge absorber in which multiple gaps are multiply formed in the direction of the main electrode, the accuracy of the discharge function in each gap is high, so the discharge start voltage can be set in proportion to the number of gaps, and the multiple gap structure It is possible to configure the surge absorber as a highly accurate one with less variation than the conventional one.

[0027]

Embodiments of the present invention will be described below. FIG. 1 is a perspective view showing an embodiment of a surge absorber 11 of the first present invention. In this surge absorber 11, a cylindrical (round bar) substrate 13 is provided inside a glass sealing body 12. The base 13 is made of a ceramic material such as alumina (Al ₂ O ₃ ) or a glass material. Resistor layers 14a and 14b made of a high resistance material are formed on the surface of the base 13 so as to face each other with a gap 17 therebetween. Main electrodes 15a and 15b, which are electrically connected to the respective resistor layers 14a and 14b, are provided at both ends of the base body 13 in the axial direction. Both main electrodes 15a and 15b are made of a metal material having a low resistance value, and are fitted to the base 13 from above the resistor layers 14a and 14b.

A lead wire 1 is attached to both main electrodes 15a and 15b.
6a and 16b are connected, and the lead wires 16a and 16b are connected.
Extend to the outside of the glass sealing body 12. Further, the inside of the glass sealing body 12 has a low pressure close to vacuum and is filled with an inert gas such as argon (Ar), helium (He), neon (Ne).

FIG. 2A is a developed view showing the gap 17 in the embodiment shown in FIG. 1 in an enlarged manner. In this surge absorber 11, the gap 17 extends in the circumferential direction of the base body 13, but has a shape in which unevenness is further repeated in the direction of both main electrodes 15a and 15b. In the example shown in FIG. The gap 17 is a wave pattern. That is, the resistor layers 14a on both sides facing each other across the gap 17
4b is a shape which alternately projects in the direction of the opposing resistor layer. Further, the gap 17 is designed so that the gap G between the resistor layers 14a and 14b always has a constant value over the entire length thereof.

An equivalent circuit showing the operation of this surge absorber is the same as that shown in FIG. 9, in which a surge is applied between the lead wires 16a and 16b, and the high resistance resistor layer 14a.
And 14b are charged with electric charges in the capacitance of the gap 17 facing each other. When this charge voltage matches the discharge start voltage,
Discharge occurs first in any part of the gap 17,
Next, discharge is generated between the resistor layers 14a and 14b in the entire gap 17. After that, the discharge develops between the main electrodes 15a and 15b.

When a surge is applied to the lead wires 16a and 16b and a discharge is generated in any portion of the gap 17, the resistor layer 14 is formed in the first discharge portion.
Damage is likely to occur in a and 14b. However, since the length dimension of the gap 17 of the corrugated pattern is sufficiently longer than the dimension of the base body 13, the gap 17 left without damage is longer than the conventional one. Therefore, in the entire length of the gap 17, the resistor layers 14a,
The number of repetitions of the surge application increases until 14b is damaged and the function as the surge absorber cannot be exerted, resulting in a long-life surge absorber.

Further, since the gap 17 has a long overall length and the opposing area of the resistor layers 14a and 14b can be made wider than that of the conventional one, when the discharge is generated in the entire region of the gap 17, the gap 17 is interposed. The discharge current flowing between the resistor layers 14a and 14b increases. Therefore, the resistor layer 14a
And 14b, that is, the discharge current during the initial discharge of the entire surge absorber before the discharge develops between the main electrodes 15a and 15b increases, and the surge energy absorption function increases. .

Further, the uneven pattern of the gap is not limited to those shown in FIGS. 1 and 2A, and various shapes can be used. For example, in the gap 17 shown in FIG. 2A, the gap extends in the direction of both the main electrodes 15a and 15b (the direction parallel to the axial direction of the base body 13) except for the arcuate portion (C). Like the gap 17a shown in FIG. 2 (B), it is possible to have a shape in which a straight line portion (d) other than the arcuate portion (c) is inclined with respect to the directions of both main electrodes 15a and 15b. Is. Alternatively, as shown in FIG. 2C, the gap 17b may have a comb tooth shape in which rectangular irregularities are repeated. Alternatively, as shown in FIG. 2D, the gap 17c may have a repeating shape of triangular irregularities (triangular wave pattern). Further, the structure shown in FIG. 3 can be used as a modification of the surge absorber 11 shown in FIG.

The surge absorber 21 includes a glass sealing body 22 and a flat-plate chip-shaped substrate 23 provided therein. The base 23 is made of glass or Al2 having a relatively high melting point.
It is formed of a ceramic material such as O3.
Resistor layers 24a and 24 are formed on the front surface and the back surface of the base body 23.
b is formed, and a gap 17 is formed between both resistor layers 24a and 24b. The shape of the gap 17 is the same as that shown in FIGS. 1 and 2A. That is, the gap 17 has a shape that extends in the width direction of the flat plate-shaped substrate 23 and that the unevenness of the waveform pattern is repeated in the direction of both the main electrodes 25a and 25b. The function and effect of this surge absorber 21 are the same as those shown in FIG.

Main electrodes 25a and 25b are electrically connected to the resistor layers 24a and 24b at both ends of the base member 23.
And lead wires 26a and 26b connected to the main electrodes 25a and 25b extend to the outside of the glass sealing body 22. The inside of the glass sealing body 22 is 100 to 500T.
It has a pressure of about orr and is filled with an inert gas such as argon. The surge absorber 2 shown in FIG.
In FIG. 1, the shape of the gap may be any one of those shown in FIGS.

FIG. 4 is a perspective view showing a second embodiment of the surge absorber of the present invention. This surge absorber 31
The basic structure of the surge absorber 11 shown in FIG.
In the same manner as above, a round bar-shaped substrate 13 and main electrodes 15a and 15b are provided inside the glass sealing body 12, and lead wires 16a and 16b extend to the outside of the glass sealing body 12. The inside of the glass sealing body 12 is 100 to 500.
An inert gas is filled at a pressure of about Torr. Resistor layers 14a and 14b made of a high resistance material are formed on the surface of the substrate 13.
Is formed, and a gap 37 is formed between the resistor layers 14a and 14b. FIG. 5 is a development view showing the gap 37 in an enlarged manner.

The gap G of the gap 37 is designed to have a constant size. Then, projections 37a and 37b projecting into the gap 37 are formed on the opposing edge portions of both resistor layers 14a and 14b. In the embodiment shown in FIGS. 4 and 5, the protrusion 37a is formed on the resistor layer 14a and the resistor layer 1 is formed.
A protrusion 37b is formed on 4b, and both protrusions 37a and 37b are provided at positions facing each other. Also, both protrusions 3
Both 7a and 37b have a triangular pattern, and triangular edge portions (e) face each other in the gap 37. Further, as shown in FIG. 4, in the gap 37 extending in the circumferential direction of the base 13, protrusions 37a and 37b facing each other are provided at a plurality of positions at a predetermined pitch.

In this surge absorber 31, when a surge is applied to the lead wires 16a and 16b, an electric field is concentrated on the edge portions (e) of the projections 37a and 37b formed on the resistor layers 14a and 14b, and the projections are formed. Discharge is first initiated at the opposing portions of the edges (e) of 37a and 37b, and this discharge triggers discharge over the entire length of the gap 37, and further develops into discharge between the main electrodes 15a and 15b.

During the response time from the application of the surge to the lead wires 16a and 16b to the start of the discharge between the main electrodes 15a and 15b, the discharge between the protrusions 37a and 37b starts after the surge is applied. The time until the completion is a major factor in determining the response time (response speed). Therefore, the response speed of the surge absorber 31 is determined by the facing distance Ga between the protrusions 37a and 37b. Similarly, the discharge start voltage is also the protrusion 3
It is determined by the spacing Ga between 7a and 37b.

In the conventional surge absorber, as shown in FIG. 10, since the resistor layers 4a and 4b face each other in parallel with each other in the gap 7 with fine irregularities formed by laser processing, a surge is applied. However, the position at which the discharge is first started is not specified, and thus the response speed and the discharge start voltage vary greatly. However, in the surge absorber 31 shown in FIG. 4 and FIG. 5, when the surge is applied, the position where the discharge is first started is specified as the portion where the protrusions 37a and 37b are formed. Moreover, both protrusions 3
The response speed and the discharge start voltage are determined by the facing distance Ga between 7a and 37b. Therefore, by forming the shapes of the projections 37a and 37b and the facing distance Ga between the projections 37a and 37b with high accuracy, the response speed (response time) of the surge absorber and the discharge start voltage can be set with high accuracy. You can do it.

If only the shapes and positions of the protrusions 37a and 37b are set with high accuracy, the edges of the resistor layers 14a and 14b at the other parts of the gap 37 are required to have very high accuracy. Not done. Conventionally, the discharge position in the gap is not specified, and accuracy is required in the entire edge portion of the resistor layer facing in the gap, whereas in the embodiment of the present invention, accuracy is required. Since it is only the protrusions 37a and 37b, it is easier to set the interval Ga that affects the start of discharge in the embodiment of the present invention.

Further, as will be described later, when the gap 37 is manufactured by an etching process, the shape of the gap 37 can be set with high accuracy as compared with the conventional laser processing, and the protrusion 3 can be formed.
It is easy to set the shapes of 7a and 37b and the facing gap Ga thereof. In addition, the edge portions (e) of the protrusions 37a and 37b
By determining the interval Ga between them with high accuracy, the discharge starting voltage can be set within the range of the minimum variation. Therefore, when the gaps 37 are multiply formed in the opposing direction of the main electrodes 15a and 15b, the discharge start voltage proportional to the number of the gaps can be set with high accuracy, and the response speed is high and the surge absorber with high discharge start voltage has high accuracy. Manufacture becomes possible.

FIG. 6 shows a modification of the surge absorber shown in FIG. The basic structure of the surge absorber 41 is the same as that shown in FIG. 3, and a flat plate chip-shaped substrate 23 is provided in the glass sealing body 22, and a resistor is provided on the front surface or the front and back surfaces of the substrate 23. Layers 24a and 24b
Are formed. The gap 37 formed in the facing portion between the resistor layers 24a and 24b has the same shape as shown in FIG.
And 24b, projections 37a and 3 protruding into the gap 37
7b is formed, and the projections 37a and 37b are formed on the base 2
A plurality of portions are formed at a constant pitch in the width direction of No. 3.

The operation and effect of the surge absorber 41 shown in FIG. 6 is the same as that shown in FIG. In addition, as shown in FIGS. 4 and 6, the protrusions 37a and 37b are formed in the gap 3
If the protrusions 37a and 37b are damaged by the discharge by forming them at a predetermined pitch at a plurality of locations within 7, the gap Ga between the other protrusions 37a and 37b will respond when the next surge is applied. The speed and discharge start voltage can be determined, and the surge absorber has a long life. The protrusion 37
It is not necessary to form a and 37b on both resistor layers, and protrusions may be provided on only one resistor layer. In this case,
The response speed and the discharge start voltage are determined by the distance between the protrusion and the edge of the opposite resistor layer that faces the protrusion.

Next, since the gaps 17, 17a, 17b, 17c and 37 shown in each of the embodiments of FIGS. 1 to 6 have an uneven shape or a shape having projections, a mask is used instead of the conventional laser processing. It is preferable to form a pattern by the etching process used. Resistor layer 1 in each of the above examples
4a, 14b and 24a, 24b are bases 13, 23
A high resistance material that can be formed into a film on the surface of the substrate by a process such as vapor deposition or sputtering is used. As the high resistance material, for example, TaSiO ₂ , CrSiO ₂ , which is composed of metal and oxide,
Ta-HfO ₂ is a mixture of metal and oxide, Cr-H
fO ₂ , SiC-Ta ₂ O ₅ , which is a mixture of oxides with carbides or nitrides, TiN-SiO ₂ , HfN-SiO ₂
Can be exemplified. Each of these materials has a high melting point, and the specific resistance can be changed within the range of 10 ⁻² to 10 ² Ω · cm.

Further, as a high resistance material, amorphous carbon such as DLC (diamond-like carbon), aluminum (Al), tantalum (Ta), niobium (N) is used.
It is preferable to use amorphous carbon containing 5 to 40 at% of b), zirconium (Zr), titanium (Ti), and chromium (Cr). Amorphous carbon has a relatively high resistance and a high resistance to an inert gas such as argon or neon filled in the glass sealing body, and is therefore suitable as a material for the resistor layer. The thickness of the resistor layers 14a and 14b is preferably in the range of 50 to 1000 nm or 200 to 500 nm.

The gaps 17, 17a, 17b, 17c,
37 can be formed by forming a film of the high resistance material on the surface of the substrate and then removing this film. This step is performed by wet etching or dry etching. If the high resistance material is amorphous carbon, CF
_The gap 13 can be processed by dry etching using a mixed gas of ₄ + O ₂ . Considering that the gap is formed by the etching process as described above, it is preferable to form the resistor layer in a planar shape on the flat-plate-shaped substrate 23 as shown in FIG. 3 or 6.

[0048]

As described above, according to the first aspect of the present invention, the device is small and has a long service life against repeated surge application.
In addition, it becomes a surge absorber with a high ability to absorb surge energy at the start of discharge.

Further, in the second aspect of the present invention, the discharge start position in the gap can be specified as the protrusion portion, and by setting the protrusion with high accuracy, the discharge start voltage and the response speed can be easily set and the discharge start The variation in voltage and response speed is small.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a surge absorber of the first present invention,

2A is a development view showing an enlarged gap shape of the surge absorber shown in FIG. 1, and FIGS. 2B, 2C and 2D are
An expanded view showing another example of the gap shape in an enlarged manner,

FIG. 3 is a perspective view showing another configuration example of the surge absorber of the first present invention,

FIG. 4 is a perspective view showing an embodiment of a surge absorber of the second present invention,

5 is a development view showing the gap shape of the surge absorber shown in FIG. 4 in an enlarged manner;

FIG. 6 is a perspective view showing another configuration example of the surge absorber of the second present invention,

FIG. 7 is a perspective view showing a conventional surge absorber,

FIG. 8 is an enlarged sectional view showing a gap portion of a conventional surge absorber,

FIG. 9 is an equivalent circuit diagram for explaining the discharge operation of the surge absorber,

FIG. 10 is an enlarged development view of a gap portion of a conventional surge absorber,

[Explanation of symbols]

 11, 21, 31, 41 Surge absorber 12, 22 Glass sealing body 13, 23 Base body 14a, 14b, 24a, 24b Resistor layer 15a, 15b, 25a, 25b Main electrode 16a, 16b, 26a, 26b Lead wire 17, 17a, 17b, 17c, 37 Gap 37a, 37b Protrusion

Front page continued (72) Inventor Isao Nakamura 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Insane Nakamura 21-6 Kurobegaoka, Hiratsuka-shi, Kanagawa

Claims (4)

[Claims] 1. A surge absorber having a resistor layer formed on a surface of a substrate and main electrodes arranged on both sides of the resistor layer, wherein one or more gaps are formed in the resistor layer. The surge absorber is characterized in that the gap has a shape in which irregularities are continuous in a direction in which the main electrodes face each other, and the resistor layers face each other at a constant interval along the entire length of the gap. 2. A surge absorber having a resistor layer formed on a surface of a substrate and main electrodes arranged on both sides of the resistor layer, wherein one or more gaps are formed in the resistor layer. The surge absorber is characterized in that the resistor layers are opposed to each other at a constant interval in the gap, and protrusions projecting into the gap are formed in the resistor layer. 3. The protrusions are respectively formed on the resistor layers on both sides facing each other across the gap, and the edge portions of the protrusions protruding from both resistor layers face each other in the gap. Surge absorber. 4. The surge absorber according to claim 2, wherein the projection is provided at a plurality of positions in the gap.