JP2509812Y2 - Discharge type surge absorber with safety mechanism - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge type surge absorbing element which absorbs a surge such as inductive lightning induced on a telephone line or the like to prevent damage to the equipment, and particularly to downsizing of outer diameter shape. The present invention relates to a discharge type surge absorbing element with a safety mechanism, which has an excellent space factor and can block continuous overcurrent flowing through the discharge type surge absorbing element.

[0002]

2. Description of the Related Art Conventionally, as a surge absorbing element for protecting an electronic circuit from a surge such as an induced lightning which is applied to the electronic circuit, a varistor made of a high resistance element having a voltage non-linear characteristic and a discharge gap are sealed in an airtight container. Stored arresters are widely used. However, although the varistor has excellent surge absorption response, it has a relatively small current withstanding capacity per unit cross-sectional area, and thus it is difficult to efficiently absorb a large surge current. Further, the arrester can increase the current withstanding capacity by generating an arc discharge in its discharge gap, but the time required from the application of a surge to the arc discharge is slower than that of the varistor, and its response Had a sex problem.

Therefore, in order to improve the response of surge absorption in the arrester, as shown in FIGS. 3 and 4, a conductive thin film 23 is deposited on the surface of a substantially cylindrical insulator 22, and then this is used. A minute discharge gap 24 having a width of about 0.1 mm is formed in a circular shape in the conductive thin film 23 to divide the conductive thin film 23, and the discharge electrodes 26, 26 are separated at both ends of the insulator 22 with a main discharge gap 25. The conductive thin film 2 by fitting
3, 23 and the discharge electrodes 24, 24 are connected to each other, and the discharge electrodes 24 and 24 are sealed together with a discharge gas in an airtight container 27 to form external terminals 28,
A surge absorbing element 21 derived from 28 has been proposed.
When a surge is applied to the surge absorbing element 21 having the minute discharge gap 24, first, a potential difference is generated between the conductive thin films 23, 23 via the minute discharge gap 24, whereby electrons are emitted to the minute discharge gap 24. Creeping discharge occurs. Next, a transition is made to a glow discharge due to the priming effect of electrons generated by the creeping discharge. And
This glow discharge is transferred to the main discharge gap 25 due to an increase in surge current, and is transferred to arc discharge to absorb the surge. As described above, since the surge absorbing element 21 having the minute discharge gap 24 utilizes creeping discharge having a high response speed originally, it has substantially the same excellent responsiveness as the varistor, and at the same time, has a high current It has a large tolerance and is excellent.

In this conventional surge absorbing element 21, as shown in FIG. 3, the airtight container 27 has a substantially cylindrical shape and is not so small as compared with so-called small electronic parts. It required a certain degree of exclusive area when it was mounted inside electronic and electrical equipment. However, in recent years electronic and electric devices have been significantly reduced in size and weight,
As a result, miniaturization of electronic components is promoted by ICs and the like, and therefore, there is a demand for further miniaturization even in the conventional surge absorbing element.

Further, the conventional surge absorbing element 21 described above is used.
Therefore, if a continuous overvoltage exceeding the rating of the surge absorbing element is applied by an overvoltage test based on safety standards such as UL and CSA assuming such accidents with the power line, the main discharge The energization of the excessive current due to the arc discharge generated in the gap 25 is maintained. Furthermore, the heat generated by the continuous energization of this excessive current causes the airtight container to melt, resulting in burnout of the circuit board on which the surge absorbing element is mounted, which does not satisfy the acceptance criteria in the overvoltage test. There were many. Moreover, when the above-mentioned phenomenon occurs in an actual use state, there is a possibility of causing a fire.

[0006]

Therefore, in the discharge type surge absorbing element with a safety mechanism of the present invention, the outer diameter shape is made smaller and the space factor is improved, and
Even if the discharge is sustained in a line accident or an overvoltage test, the burnout accident can be prevented by cutting off the overcurrent, and the discharge with a safety mechanism that complies with the safety standard is excellent. Type surge absorber is intended to be realized.

[0007]

In order to achieve the above-mentioned object, the discharge type surge absorbing element of the present invention has a discharge space in which a discharge gas is sealed and is provided on an insulating substrate hermetically covered by a lid member. a conductive thin film opposed pairs across a small discharge gap, are connected to the conductive thin film and electrically, the discharge electrode film opposed pairs deposited formed at a main discharge gap, and
In addition, the central part of the insulating board is mounted in a floating state.
External terminals for both sides facing each other in the insulating board
It extends downward from the end face and extends almost vertically.
In addition, the external terminal is electrically connected to the discharge electrode film, and the resistance value of the conductive thin film is a resistance value that generates a calorific value capable of crushing the insulating substrate due to thermal strain when a continuous overcurrent flows. It is characterized by that.

[0008]

A conductive thin film, which is opposed to the surface of an insulating substrate, which is covered with a lid member in a hermetically sealed manner, with a discharge space filled with a discharge gas, is electrically connected to the conductive thin film. In addition, by depositing and forming a discharge electrode film facing each other across the main discharge gap, the shape of the discharge type surge absorbing element is flattened, and the size can be easily reduced. Furthermore, the central part of the insulating substrate is mounted in a floating state.
External terminals for insulating both sides of the insulating substrate facing each other
While extending downward from the surface in a substantially vertical direction,
This external terminal is electrically connected to the discharge electrode film,
The discharge type surge absorber with a safety mechanism is the central part of the insulating substrate.
Are mounted in a floating state, which allows the insulating substrate to
Since it is not supported in close contact with the plate, etc.,
Insulation substrate easily breaks when a large amount of energy is applied
It will be. Further, the resistance value of the conductive thin film, that the insulating substrate has a resistance value that produces a calorific value which can be砕裂by thermal strain when continuous overcurrent flows exceeds the rating of the discharge surge absorbing element continuously When the overcurrent flows through the conductive thin film, the insulating substrate is crushed and air flows into the discharge gas in the discharge space, which causes the discharge to disappear and shut off the overcurrent. It is possible to prevent the discharge type surge absorber with a mechanism from burning.

[0009]

1 is an exploded perspective view showing a discharge type surge absorbing element with a safety mechanism of the present invention, and FIG. 2 is a sectional view showing a discharge type surge absorbing element with a safety mechanism of the present invention.

In the figure, 1 is a discharge type surge absorbing element with a safety mechanism of the present invention, 2 is an insulating substrate made of ceramic or the like having a thickness of 0.4 to 1.0 mm, and 3 and 3 are on the surface of the insulating substrate 2. A conductive thin film such as a cermet resistor having a resistance value of 5 to 100 Ω formed by depositing a ruthenium (Ru) -based paste with a small discharge gap 4 having a width of 10 to 200 μm, 5, 5
Are electrically connected to the respective end portions of the conductive thin films 3 and 3 and face each other with a main discharge gap 6 and 6 of about 0.4 to 3.0 mm, and molybdenum (Mo), tungsten (W),
Lanthanum hexaboride (LaB ₆ ), molybdenum disilicide (M
OSI _2), the discharge electrode film made of a conductive substance having a sputtering resistance, such as titanium dioxide (TiO _2), 7,7 is insulated from the conductive thin film 3, 3 and the discharge electrode film 5 and 5 substrate 2
External terminal connection coatings made of silver-palladium (Ag-Pd), nickel (Ni), or the like, deposited on the side end surfaces 2a, 2a of the above, 8 and 8 are connected to the external terminal connection coatings 7 and 7, and One end is fixedly provided on both end surfaces 2a, 2a of the insulating substrate 2 which face each other, and the other end extends in a substantially vertical direction downward of the insulating substrate 2 as a connecting portion for a circuit board or the like.
External terminal made of leaving the conductive metal, 9, 9 to coat the exposed portion of the conductive thin film 3, 3, a protective film made of non-crystallized glass for preventing creeping discharge in the exposed portion Numeral 10 is a lid member formed on all sides with a brim 10a and made of an insulating material (glass in this embodiment) such as glass or ceramic.
A sealing member made of low-melting glass for hermetically sealing the surface. The lid member 10 has a height of about 3 to 10 mm and covers the minute discharge gap 4 between the conductive thin films 3 and 3 and the main discharge gaps 6 and 6 between the discharge electrode films 5 and 5. The discharge space 12 is formed inside the lid member 10 by sealing the brim 10a to the insulating substrate 2. Then, in the discharge space 12, helium (He), neon (N)
e), argon (Ar), xenon (Xe), and other rare gases are contained in a discharge gas mainly containing a single substance or a mixture. The lid member 10 may have a flat plate shape. In this case, a spacer or the like may be arranged between the lid member 10 and the insulating substrate 2 to form the discharge space 12. Further, in the portions of the conductive thin films 3 and 3 facing the minute discharge gap 4, molybdenum (Mo), tungsten (W), lanthanum hexaboride (LaB ₆ ), the same as in the discharge electrode films 5 and 5, Conductive substances 13 and 13 having sputter resistance such as molybdenum silicide (MoSi ₂ ) and titanium dioxide (TiO ₂ ) are deposited. This prevents insulation deterioration of the minute discharge gap 4 due to sputtering of the conductive thin films 3 and 3 and improves life characteristics. Of course, even with a discharge type surge absorbing element in which the conductive materials 13 and 13 are not formed on the conductive thin films 3 and 3, the surge absorbing characteristic itself does not change.

However, in the discharge type surge absorbing element 1 with a safety mechanism having the above-mentioned structure, the external terminals 8 and 8 are externally applied while being mounted on the printed circuit board of the equipment.
When a surge such as inductive lightning is applied via the micro electric discharge gap, a potential difference is generated between the conductive materials 13, 13 via the micro electric discharge gap 4, so that electrons are emitted to the micro electric discharge gap 4 and a creeping discharge is generated. . Next, this creeping discharge shifts to glow discharge due to the priming effect of electrons generated by the discharge. Then, this glow discharge is transferred to the main discharge gap 6 due to the increase of the surge current, and is further transferred to arc discharge to absorb the surge.

Further, in the discharge type surge absorbing element 1 with a safety mechanism of the present invention, a continuous overvoltage exceeding the rating of the discharge type surge absorbing element is applied by an overvoltage test assuming a contact accident with a power line or such a situation. In this case, the discharge in the minute discharge gap 4 does not transfer to the main discharge gap 6, the discharge continues in the minute discharge gap 4 or the minute discharge gap 4 and the main discharge gap 6, and a continuous overcurrent is generated through this discharge. It will flow. Then, when such a short circuit occurs, the conductive thin films 3 and 3 generate heat due to their resistance values, and the insulating substrate 2 is thermally distorted and shattered, whereby the discharge gas in the discharge space 12 is discharged. The air flows into the device to extinguish the discharge, and as a result, the overcurrent is shut off. Further, in the discharge type surge absorber 1 with a safety mechanism of the present invention, the opposite end surfaces 2a, 2 of the insulating substrate 2 facing each other are provided.
Since the external terminals 8 and 8 are fixed to a in a direction substantially perpendicular to the insulating substrate 2, when connecting the external terminals 8 and 8 to a circuit board or the like, a circuit board or the like such as a so-called chip type electronic component is connected. When the conductive thin films 3 and 3 generate heat that may crush the insulating substrate 2, the insulating substrate 2 is crushed when the conductive thin films 3 are crushed. It is easy to tear.

[0013]

As described above in detail, according to the discharge type surge absorbing element with a safety mechanism of the present invention, a minute discharge gap is formed on the surface of the insulating substrate which is hermetically covered by the lid member with the discharge space. By forming a conductive thin film facing each other and a discharge electrode film which is conductive with the thin conductive film and faces the main discharge gap, the shape of the discharge type surge absorber with the above configuration is flattened and small. It is possible to expand the usage of the discharge type surge absorption element with a safety mechanism and to increase its utility value, since it can be easily realized and can be accommodated in a small device with a small space for accommodating components. .
In addition, the central part of the insulating board is mounted in a floating state.
External terminals on both sides of the insulating substrate facing each other.
And extends in a substantially vertical direction,
Since the external terminals are electrically connected to the discharge electrode film, the safety of the present invention is improved.
The discharge type surge absorber with a mechanism floats in the center of the insulating substrate.
It is mounted as it is, so that the insulating board becomes a circuit board, etc.
Since it is not supported in close contact with the
Insulative substrate easily breaks when energy is applied
Things. In addition, in the discharge type surge absorber with a safety mechanism of the present invention, the resistance value of the conductive thin film is set to a resistance value that generates a calorific value capable of crushing the insulating substrate due to thermal strain when a continuous overcurrent flows . Therefore, when a continuous overcurrent exceeding the rating of the discharge type surge absorption element flows by an overvoltage test assuming such a situation as a contact with a power line or such a situation, the insulating substrate is heated due to the large heat generation of the conductive thin film. Disruption is caused by crushing and injecting air into the discharge gas, and as a result, overcurrent is cut off to prevent burnout accidents due to the discharge type surge absorbing element, which in turn has excellent safety and complies with various safety standards. It is possible to realize a discharge type surge absorber with a safety mechanism that is well suited.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a discharge type surge absorber with a safety mechanism according to the present invention.

FIG. 2 is a cross-sectional view of a discharge type surge absorber with a safety mechanism of the present invention.

FIG. 3 is a schematic perspective view of a conventional surge absorbing element.

FIG. 4 is a schematic sectional view of a conventional surge absorbing element.

[Explanation of symbols]

 1 Discharge type surge absorber with safety mechanism 2 End face of insulating substrate 2a 3 Conductive thin film 4 Micro discharge gap 5 Discharge electrode film 6 Main discharge gap 8 External terminal 10 Lid member 12 Discharge space

Claims (1)

(57) [Scope of utility model registration request] 1. A pair of conductive thin films facing each other with a small discharge gap on an insulating substrate which is hermetically covered with a lid member and which is provided with a discharge space filled with a discharge gas, and the conductive thin film and the electrically conductive thin film. And a pair of discharge electrode films facing each other across a main discharge gap are formed by deposition, and the center of the insulating substrate is further formed.
The external terminal for mounting the part in a floating state
Face downward from the opposite end faces of the edge substrate
While extending in a substantially vertical direction, this external terminal
And a resistance value of the conductive thin film which is electrically conductive with the electrode film and is a resistance value that generates a calorific value capable of crushing due to thermal strain of the insulating substrate when a continuous overcurrent flows. Discharge type surge absorber with safety mechanism.