JPH1154357A - Electronic component with safety function and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate fuming or inflaming, by a method wherein an external terminal is fixed to one external electrode via a glass layer, an insulative ceramic layer or these composite layers, and a fuse is connected between this external terminal and the external electrode, and the external electrode is connected to the other external electrode. SOLUTION: A rectangular external terminal 5 is fixed to one external electrode 2 via a glass layer 3, and this external terminal 5 is connected to the external electrode 2 via a current fuse 7. Further, the other external electrode 2 is connected to a rectangular external terminal 6. With this structure, when an overcurrent continuously flows in a capacitor element 1, the current fuse 7 is melted and a capacitor is separated from a circuit. As a result, it is possible to prevent previously fuming, inflaming, other stains and damages of other electronic parts, etc., connected to the capacitor or circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component such as a ceramic capacitor and a ceramic varistor and a method for manufacturing the same.

[0002]

2. Description of the Related Art Electronic components surface-mounted on electronic circuit boards include, for example, ceramic capacitors and ceramic varistors. These electronic components include a laminate type, a single plate-like component, and a component in which a plurality of plate-like components are used by laminating them. There is a configuration in which a metal cap is fitted into the external electrode formed in the above, and a lower portion of the cap is soldered to a circuit board. FIG. 4 shows a configuration of a conventionally used ceramic capacitor with a cap. That is, external electrodes 12 are formed on both side surfaces of the two ceramic capacitor elements 11, and an adhesive 13 made of epoxy resin is applied between the lower and upper surfaces of the two capacitor elements 11 to be bonded in a plane. Alternatively, two electronic component elements are integrated by baking the electrode material applied to the external electrode portion to form a capacitor element group, and a cap 14 previously coated with cream solder on its inner surface is fitted to the capacitor element 11 group. The external electrode 12 of the capacitor element 11 was connected to the cap 14 by drying and heating to melt the cream solder. Note that 15
Is a circuit board.

However, such a ceramic capacitor with a cap has a configuration in which the external electrode 12 of the capacitor element 11 and the metal cap 14 are connected, so that a voltage higher than the rated voltage is applied to the capacitor element 11 or the like. If an overvoltage due to direct lightning or induced lightning is applied, the insulation characteristics will deteriorate and the leakage current will increase.If the device is used continuously, smoke and fire will occur due to thermal runaway due to self-heating, and the There have been problems such as fouling and burning of electronic components.

In some cases, such a ceramic capacitor with a cap is electrically short-circuited due to a malfunction of the capacitor element 11 itself. In this case, a short-circuit current flows and heat is generated, causing a current runaway due to the heat generation. May emit smoke or fire.

[0005]

As described above, in a conventional electronic component with a cap, an electronic component such as a capacitor element is integrated with a metal cap by using cream solder to form an electronic component. When a voltage higher than the rated voltage of the electronic component is applied, an impact voltage such as a lightning surge is applied, the electronic component element is deteriorated, and the current continues to flow due to the deterioration of the electronic component element itself. However, there is a problem in that heat is generated and heat runaway causes smoke and ignition, thereby damaging not only the electronic components but also a group of surrounding electronic components.

In order to protect an electronic circuit from smoke or ignition due to the above-mentioned excessive current or thermal runaway, there is a type in which a current fuse or a temperature fuse is incorporated in an electronic component. An insulating material is disposed between the metal cap and the cap, and the metal cap and the external electrode are connected by a fuse. In this configuration, one process is required for forming the insulating material, and there are problems such as displacement of the insulating material, deterioration of the insulating material of the insulating material → conductivity → inactivation of the fuse.

The present invention solves such a drawback. Even if an overvoltage flows through the electronic component or the electronic component itself deteriorates to cause thermal runaway, the external electrodes and the external terminals of the electronic component element can be used. The purpose of the present invention is to provide an electronic component which does not emit smoke or fire by interrupting a circuit by a fuse provided in a part of the connection with the electronic device.

It is another object of the present invention to provide a method of manufacturing an electronic component, in which glass, ceramic or a composite material thereof formed between an external electrode and an external terminal is formed at the same time as the external electrode, so that the number of steps is not increased.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to an electronic component element having a pair of external electrodes, wherein one of the external electrodes has a glass layer, an insulative ceramic layer, or the like. An electronic component with a security function in which an external terminal is fixed via these composite layers, a fuse is connected between the external terminal and the external electrode, and the external terminal is connected to the other external electrode.

In the electronic component with a security function according to the first aspect, an external terminal is fixed to one external electrode via a glass layer, an insulating ceramic layer, or a composite layer thereof.
Although the external terminals and the external electrodes are connected by a fuse, the operation is simple because the external terminals are fixed on a glass layer, an insulating ceramic layer, or a composite layer thereof. When a fuse is provided in an electronic component, it is necessary to keep the external terminal away from the external electrode.Therefore, it is conceivable that the external terminal is fixed to a place away from the external electrode and both are connected by a fuse. However, in such a configuration, there are problems such as contact between the external terminals and the external electrodes and difficulty in work because the electronic components are small articles.

[0011] Even if a voltage higher than the rated voltage is applied to the electronic circuit to which the electronic component according to the present invention is connected, thereby deteriorating the electrical characteristics of the electronic component and continuing the overcurrent,
Since the current fuse connecting the external terminal and the external electrode is blown, the electronic component is cut off from the electronic circuit, and damage to electronic circuit components other than the electronic component can be avoided.

When a thermal fuse is used as a fuse, a voltage higher than a rated voltage is applied to an electronic circuit to which the electronic component is connected, or an overcurrent continues to flow due to deterioration of the electronic component itself. Even if heat is generated and the heat of the electronic component rises due to thermal runaway due to the generated heat, the thermal fuse is blown, so that the electronic component is cut off from the electronic circuit, and damage to electronic circuit components other than the electronic component is avoided. be able to.

Since the glass and the insulating ceramic do not become conductive due to the deterioration of the insulating properties, there is no problem that the external electrode and the external terminal are conducted and the security function does not operate.

[0014] The invention described in claim 2 is the first invention.
In the electronic component with security function described, one external terminal has a U-shape or a configuration in which a notch is provided in a part of a box shape, and the other external terminal has a U-shape or a box shape. Features.

The connection surface of the external electrode for connecting the fuse to the external terminal may be any of the five surfaces of the external electrode. One of the external terminals for connecting the fuse has a U-shape or a box-like portion provided with a notch, and the fuse is connected at an external electrode portion exposed from the notch. You can also.

According to a third aspect of the present invention, in the electronic component with a security function according to the first or second aspect, one of the external terminals has a glass layer, an insulative ceramic layer, or a composite layer thereof formed in advance on the inner surface. It is characterized by having. By using such an external terminal, it is possible to fix the external terminal on which a glass layer, an insulating ceramic layer or a composite layer thereof is formed in advance by a simple operation of bonding the external terminal to the external electrode of the electronic component element. it can.

The U-shaped or box-shaped shape and dimensions of the external terminals are set in accordance with the shape of the electronic component element, for example, a rectangular parallelepiped or a cube.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an electronic component having a security function, wherein a step of applying a pair of external electrode materials to an electronic component element and a step of thermally melting one external electrode of the electronic component element are performed. Applying an inorganic material to become glass, insulating ceramic or a composite material thereof, and firing the electronic component element at a predetermined temperature to produce an external electrode and the glass layer, ceramic layer or a composite layer thereof. Connecting an external terminal on the glass layer, on the ceramic layer or on a composite layer thereof, and on the other external electrode, and connecting the external terminal on the glass layer, on the ceramic layer or on the composite layer And a step of connecting the external electrode and the external electrode with a fuse.

According to this manufacturing method, there is a feature that the external electrode material applied to the electronic component element and the inorganic material which becomes a glass, an insulating ceramic or a composite material thereof by heat melting can be simultaneously fired. Conventionally, since an insulating material such as a resin is used, it is necessary to separately fire and cure the external electrode material and the resin or the like as the insulating material, which requires a plurality of steps.

[0020]

An embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, two ceramic capacitor elements 1 were each coated with a conductive paint containing silver-palladium (hereinafter referred to as Ag-Pd) as a main component, and dried to form external electrodes 2. A glass material made of zinc borosilicate was applied on one of the external electrodes 2 of the two groups of capacitor elements 1 to form a glass layer 3 and then fired at 750 ° C. By this firing,
The conductive paint of the external electrode 2 and the glass material forming the glass layer 3 are simultaneously baked.

The two capacitor elements 2 were bonded with an adhesive 4 made of epoxy resin, and a U-shaped external terminal 5 was bonded on one of the external electrodes 2 provided with the glass layer 3.

The other external electrode 2 serving as a counter electrode has
A U-shaped external terminal 6 in which cream solder was applied to the inner surface in advance was fitted, heated, and connected to the external electrode 2.

Further, a current fuse 7 connects between the U-shaped external terminal 5 and the external electrode 2.

As described above, one external electrode 2 is
A U-shaped external terminal 5 is fixed via the glass layer 3, and the external terminal 5 is connected to the external electrode 2 by a current fuse 7.
And the other external electrode 2 is connected to a U-shaped external terminal 6.
Therefore, if an overcurrent continues to flow through the capacitor element 1, the current fuse 7 is blown and the capacitor is disconnected from the circuit, so that the capacitor and other electronic components connected to the circuit can be used. Smoke, fire, and other pollution and damage can be prevented.

In the above embodiment, the case where a current fuse is used has been described. However, similar effects can be obtained by using a temperature fuse depending on the situation of an electronic circuit or the like, and Ag-Pd used as an external electrode material can be obtained. In place of Ag, aluminum borosilicate or an insulating ceramic, or a composite material of glass and ceramic may be used in place of zinc borosilicate used as glass.

Although the case where U-shaped ones are used as the external terminals 5 and 6 has been described, as shown in FIG. An external terminal 5a having a shape in which a notch portion 8 is provided in the outer electrode and the external electrode exposed from the notch portion 8 is connected with a fuse, and a box-shaped external terminal is used as the other external terminal. Is also good. The external electrode surface to which the fuse is connected can be connected not only to the upper surface of the electronic component element shown in the above-mentioned embodiment but also to five surfaces of the side surface, the front surface, the rear surface, and the lower surface. The connection direction of the external terminal to the external electrode is not necessarily limited to the connection fitting from both sides of the electronic component element as in the embodiment, and the connection from the front surface or the rear surface of the electronic component element is also possible. . In any of the above-described cases, it is necessary that a glass layer, an insulating ceramic layer, or a composite layer thereof is disposed between one external electrode for connecting the fuse of the capacitor element and the external terminal.

Further, as shown in FIG. 3, a glass layer, an insulating ceramic layer or a composite layer 3b thereof is formed in advance on one external terminal 5b for connecting a fuse, and this is bonded to an external electrode by bonding or the like. The same effect can be obtained even if fixed. At this time, the width of the glass layer 3b or the like is preferably equal to or larger than the width of the external electrode 5b.

In the above embodiment, the case where a ceramic capacitor is used as an electronic component has been described. However, the present invention can also be applied to a varistor, a resistor, or an electronic component that is a combination thereof.

[0029]

As described above, in the electronic component according to the present invention, the fuse connected between one external electrode and the external terminal of the electronic component element can be used even if deterioration due to overvoltage or heat generation of the electronic component occurs. As a result, there is no smoke or ignition, and it is possible to obtain an effect that other electronic components incorporated in the same substrate or the like are not stained or burnt.

Further, since the external electrode and the glass layer, the insulating ceramic layer or the composite layer formed on the external electrode can be fired at the same time, the production process can be shortened.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an electronic component according to the present invention.

FIG. 2 is a perspective view showing another embodiment of the external terminal used in the present invention.

FIG. 3 is a perspective view showing an external terminal on which an insulating material layer used in the present invention is formed.

FIG. 4 is a front view showing a conventional electronic component element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ceramic capacitor element 2 ... External electrode 3 ... Glass layer 4 ... Adhesive 5 ... One external terminal 6 ... The other external terminal 7 ... Current fuse

Claims (4)

[Claims] An electronic component element having a pair of external electrodes, or an electronic component element group in which two or more electronic component elements are bonded, a glass layer on one external electrode of the electronic component element,
An external terminal fixed via an insulating ceramic layer or a composite layer thereof, a fuse connected between the external terminal and the external electrode, and an external terminal connected to the other external electrode of the electronic component element. Electronic components with security functions. 2. The method according to claim 1, wherein one of the external terminals has a U-shape or a box-like shape and a cutout portion is provided in a part thereof, and the other external terminal has a U-shape or a box-shape. Item 2. An electronic component with a security function according to Item 1. 3. The electronic component with a security function according to claim 1, wherein one of the external terminals has a glass layer, an insulating ceramic layer, or a composite layer thereof formed on the inner surface. 4. A step of applying a pair of external electrode materials to the electronic component element, and a step of applying an inorganic material which becomes a glass, a ceramic, or a composite material thereof by thermally melting one external electrode of the electronic component element. And firing the electronic component element at a predetermined temperature to produce an external electrode and a glass layer, an insulating ceramic layer or a composite layer thereof, and
A step of connecting external terminals on the ceramic layer or on these composite layers, and on the other external electrode, and on the glass layer, on the ceramic layer or on these composite layers, the external terminals and the external electrodes; A method of manufacturing an electronic component with a security function, comprising the steps of: connecting an electronic component with a fuse.