KR100199694B1 - Surge absorber - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount surge absorbing element of a printed circuit board for protecting a communication device from surges.

Conventionally, by cutting and bending the lead wire, inserting it into the hole of the substrate, and soldering it, excessive manpower consumption is caused, and there is a manufacturing problem, particularly as a poor connection and surface mount type.

The present invention has been invented by correcting such a problem, and thus, a discharge gap is formed to form an electrode having a gap formed on the plane of the substrate and an airtight cap surrounding it.

Description

Surge Absorption Element

1 is a cross-sectional view of a surge absorbing device according to the prior art.

2 is a sectional view of Embodiment 1 of the surge absorption element according to the present invention, (a) is a sectional view, and (b) is a plan view.

3 is a cross-sectional view of another embodiment according to the present invention.

4 is a sectional view of an embodiment according to the present invention.

5 is another example of the present invention, (a) is a plan view, (b) is a sectional view.

6 is another embodiment of the present invention, (a) is a sectional view, (b) is a plan view,

7 is a cross-sectional view according to another embodiment of the present invention, (a) and (b) are plan views, (c) and (a) are ab.

* Explanation of symbols for main parts of the drawings

1a, 1b: Pair of electrodes 2: Microgap

5: glass tube 21: substrate

22a, 22b: electrode 23: microgap

24: glass film 25: airtight cap

26: sealing material 27a, 27b: electrode terminal

31 substrate 32a, 32b electrode

33: microgap 34: glass film

35: airtight cap 36: sealing material

37a, 37b: electrode terminal 41: substrate

42a, 42b: electrode 43: microgap

44: glass film 45: airtight cap

48: sealing material 51: substrate

52a, 52b: electrode 61: substrate

62a, 62b: electrode 62a ', 62b': fixed electrode

72a, 72b: electrode 80: removal

[Industrial use]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to microgap or gap type surge absorbing devices, and more particularly, to surface mount type surge absorbing devices that are advantageous for automatic mounting on printed circuit boards.

[Prior art]

A surge absorbing element for protecting a communication device such as a telephone and a facsimile from a surge is a pair of electrodes 1a and 1b forming a micro gap 2 as shown in FIG. Formed on the columnar insulator surface, the electrodes 3a, 3 attached to each of the insulator pairs 1a, 1b with lead wires were mounted, and the pressurized glass tube 5 was hermetically sealed with .

Conventional micro-gap surge absorbing elements require cutting of the feed line to a suitable length and bending in mounting the printed circuit board with the lead wire 4 around 25 mm as shown in FIG. After that, the lead wire was inserted into the hole of the printed circuit board and soldered. However, as is well known, such a method of mounting a printed circuit board requires a lot of manual labor by manpower, and many electronic components have been changed into surface-mounted or so-called surface-mounted electronic components.

An object of the present invention is to provide a microgap type surge absorbing device which is easy to mount and advantageous in manufacturing.

[Means to solve the problem]

Summary of the Invention The present invention includes a pair of electrodes arranged to form microgaps or gaps electrically insulated from each other on the same plane of the substrate, and a portion of each of the pair of electrodes around the microgap or gaps includes a plane of the substrate. The main part of the microgap surge absorbing element is formed by forming a discharge space by an airtight cap formed so as to enclose and a pair of external electrodes on the same plane are arranged on the flat substrate by placing external electrodes for mounting on a printed circuit board. The surface mounting in the printed circuit board by this is enabled.

Next, the surge absorbing element of the present invention will be described by specific examples, but the present invention is not limited to the present description.

Example 1

2 shows an example of a surge absorbing element according to the present invention in cross section (a) and plan view (b). A pair of electrodes 22a and 22b are printed and fired on the main surface of the insulating substrate 21 such as a lightless or alumina by a screen printing method and then fired to form a micro gap between the pair of electrodes 22a and 22b. 23). The method of forming a microgap has a method of printing and baking integrally with the method of separating and printing the electrodes 22a and 22b, and then cutting it with a laser to form a gap.

The glass film 24 covering a part of the pair of electrode surfaces is effective to improve the sealing property when sealing the airtight cap 25. In the case of sealing by soldering, short-circuiting of the electrodes 22a and 22b by soldering is prevented.

An airtight cap 25 is formed on the glass film 24. The airtight cap 25 is preferably metal such as copal or glass ceramic. Moreover, although glass frit is suitable for sealing of the airtight cap 25 to the board | substrate 21 surface, the method of using soldering is also possible.

In this case, it is preferable to form a conductor film, such as a solder, a pre-solderable paradium, molybdenum alloy, or tungsten alloy, on the surface of the soldering portion by screen printing, firing or vapor deposition, sputtering, CVD (Chemical Vapor Deposition), or the like.

26 in the figure is a sealing material for sealing the airtight cap 25 on the substrate 21 surface.

In the case of sealing the airtight cap, vacuum evacuation is performed to partially replace the gas with argon gas or the like, and then heat the glass frit or lead under a predetermined pressure to seal the cap.

As apparent from the above description, a surface mountable surge absorption element is possible.

In addition, it is also clear that the surface mount surge absorbing element, which is advantageous in the mounting surface, can be obtained with high mass productivity, as a result of such a device being able to utilize a highly productive film forming technology such as screen printing technology. Furthermore, the following effects were observed in the characteristics of surge absorbing elements. That is, as shown in FIG. 1, when compared with the conventional surge absorbing elements, these elements radiate heat by the lead wires around 0.5mm in diameter, and in the surge absorbing element of this embodiment, It is based on the wide electrode terminals 27a and 27b, which is not less than 4 times as compared to the cross-section of the electrode, and the heat dissipation is improved, resulting in a long life as a surge absorbing element. The amount to withstand (Surge) is also improved by more than 20% compared to the conventional device.

Example 2

3 shows another embodiment of the present invention. In the present embodiment, a conductive substrate such as aluminum is used for the substrate 31. In the case of an aluminum substrate, the substrate surface is covered with an insulating film 38 such as an aluminum oxide film such as Al ₂ O ₃ .

In case of using such a material, since the substrate difference has a high thermal conductivity, the heat dissipation caused by the surge of a large current is significantly improved when operating as a surge absorbing element. Absorption element which does not deteriorate characteristic as an absorption element is provided.

In the figure, 32a and 32b are electrodes, 33 are microgaps, and 34 are insulating films such as glass films.

In addition, although the glass film 34 is effective for improving airtight sealing property, it is also possible to seal on an electrode directly.

And 36 is a sealing agent for hermetically adhering the hermetic cap 35, 37a 37b is an electrode terminal made of copal and the like.

In addition, as shown in FIG. 1, in comparison with the conventional surge absorbing elements, the thermal conductivity of the surge absorbing element of the present embodiment is higher than that of these elements by heat dissipation by lead wires having a diameter of about 0.5 mm. The heat dissipation from the entire surface of the excellent substrate 31 is remarkably improved, and thus the heat dissipation is remarkably improved. As a result, the lifespan of the surge absorbing element as well as the amount of surging surges are improved by 35% or more.

Example 3

4 is another embodiment of the present invention, in which 41 is an insulating substrate, 42a and 42b are a pair of electrodes formed by printing firing, and 43 is a gap formed between a pair of electrodes 42a and 42b.

In addition, 44 is an insulating film, such as a glass film, and 45 is a cap which is a lid for hermetic sealing. Compared with Example 1 and Example 2, the point which seals with a flat lid differs.

In the case of a flat lid, there is an advantage of not needing an expensive mold because the lid molding operation as in the case of a lid is unnecessary, and the degree of freedom in selecting materials is high because of the flatness.

However, in order to ensure the airtight space formed by making the space | interval of a pair of electrode 42a, 42b and a lid appropriate, a thick sealing material is needed.

It is effective to attach the sealing material thickly or to add the sealing material in advance using a material having a higher melting point than the sealing material such as frit.

Example 4

Figure 5 shows another example of the present invention. It is a structure that a pair of electrodes is made on the back side through the through hole by printing and firing on a ceramic substrate having a multi-sided through hole. In this case, special electrode terminal mounting is unnecessary. The cost saving effect is large due to the reduction of labor.

In the figure, 51 is a ceramic substrate, 52a and 52b are a pair of electrodes (the state before a gap is formed by laser cutting) and an external connection electrode, and 59a and 59b are the electrically conductive films which connect the electrodes of the front and back sides of a board | substrate.

Example 5

In the above embodiment, the pair of electrodes 27a, 27b, 37a, 37b, 47a, and 47b have been described using printing, firing, or thick film technology. It is effective to apply and does not impair the gist of the present invention.

That is, as a pair of electrode negotiation methods, a conductive thin film having a high melting point such as TiN and tungsten molybdenum is formed by an electron beam deposition method, a sputtering method, a CVD (Chemi-cal Vapor Deposition) method, an ion plating method, and processed by laser, The same effect can be obtained by forming a gap.

In addition, in the case of a thin film, since the thickness of the film is thin, there is an advantage in that a step between the substrate and the substrate becomes small, so that an airtight sealing operation is easier than in the case of a thick film.

The surge absorbing device of the present invention is a surface-mount surge absorbing device without lead wire compared to the conventional surge absorbing device having 2 minutes of lead wire, and can greatly improve productivity when mounting a printed circuit board. In addition to improving the heat dissipation generated during surge application of large currents, surge absorbing devices can be provided with a significantly improved amount to withstand surges.

In addition, alignment of lead wires that are easily deformed, cylindrical lids and glass tubes that are easy to roll, and alignment or the like are difficult to automate in handling and cost reduction.

However, in the present invention, a large number of devices can be formed at the same time by using a multi-sided substrate, and electrodes can be formed by a thick film or thin film formation technology, and the positional relationship of the elements on the multi-sided substrate is accurate. This simple jig is easy to align and easy to automate, improving productivity and reducing costs.

Example 6

6A and 6B show another example of the present invention.

In the figure, 61 is a substrate, 62a, 62b, and 62a '62b' are electrodes, and these electrodes are composed of parts having different resistivities. That is, it consists of the electrode parts 62a and 62b with high resistivity, and the 62a 'and 62b' electrode parts with low resistivity.

As a result, the discharge initiated by the gap 63 'is enlarged on the electrode, so that it is possible to easily move between the electrodes 62a' and 62b ', so that the discharge is easy to concentrate and thermally damaged. It can improve the service life.

In the figure, 65 is a lid, 67a and 67b are a pair of electrode terminals.

As the electrodes 62a and 62b, a high melting point metal such as W, Ta, Mo, etc. having high thermal stability is formed by an electron beam deposition method, a sputtering method, or a CVD (chemical vapor deposition) method.

Dozens In 1000 The thickness of is effective.

In addition, the resistivity varies depending on the amount of the dop of impurities, and semiconductors such as Si having a relatively high melting point are also effective.

Au, Cu, Ni, etc. are effective for the electrodes 62a ', 62b', but it is also effective to thicken the solid-state melting point metals such as electricity, W, Ta, and Mo to lower the resistance. One kind is advantageous in terms of equipment investment and process control.

Example 7

In the electrode of Example 6, the electrode films of 62a, 62b and 62a ', 62b' were formed in a single layer, and the high resistance portion corresponding to 62a and 62b was reduced to reduce the planar shape (or electrode area) of the electrode, thereby achieving an equivalent effect. It is an Example obtained.

7a and 7b show another embodiment of the present disease.

In the figure, 72b and 72b are a pair of electrodes. From 10,000 It consists of a thin film or a printed and fired resistor.

In the present invention, a portion of these electrodes in the vicinity of the gap 73 is removed to reduce the planar shape (or cross-sectional area) of the electrodes, thereby increasing the resistance. In the figure, 80 and 80 'are the removal parts of the electrodes, whereby the resistances of the 72a' and 72b 'portions extending from the electrodes 72a and 72b to the gap portions are high, whereby the discharge easily proceeds to 72a' and 72b 'and thus the gap portions are removed. The electrode life is extended.

In addition, when the gap 73 is formed and the removal portion 80 is formed by a photo etching method, the batch process can be performed in the same process.

It is also possible to carry out as a continuous process by laser cutting as in the previous embodiment.

In this case, however, if the outer periphery of the removal unit is removed from the line, the wrapped part is separated from the surrounding electrode, and thus the same effect as the removal can be obtained.

Claims (1)

A pair of electrodes electrically insulated from one another on the same plane of the substrate and arranged to form a microgap or gap, and a portion of each of the electrical microgap or gap and a pair of electrodes around the gap to surround the electrical substrate A microgap or gap surge absorbing element having an airtight cap or lid and a pair of electrodes formed on both end surfaces of an electric substrate.