TWI697022B - Fuse unit, fuse element, protection element, short circuit element, switching element - Google Patents

Abstract

The present invention provides a fuse unit that can be surface-mounted and that can simultaneously achieve rated lift and fast fuse.

In the fuse unit, three or more metal layers with different melting points are stacked.

Description

Fuse unit, fuse element, protection element, short circuit element, switching element

The present invention relates to a fuse unit constructed on a current path that can be fused by self-heating or heating of a heating element when a current exceeding a rated current flows to block the current path, particularly a fuse with excellent quick-breaking properties Unit, and fuse element, protection element, short circuit element, and switching element using the fuse unit.

This application claims priority based on the Japanese Patent Application No. Japanese Patent Application No. 2014-229360 filed in Japan on November 11, 2014, and refers to the application to apply it to this application.

In the past, there has been used a fuse unit that fuses by self-heating to interrupt the current path when a current exceeding the rated current flows. As the fuse unit, for example, a holder-fixed fuse formed by sealing a solder into a glass tube, or a wafer fuse with Ag electrodes printed on the surface of a ceramic substrate to make a part of the copper electrode thinner and assembled in a plastic box Screw or plug-in fuse, etc.

[Prior Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2011-82064

However, the above-mentioned known fuse unit has been pointed out that there are problems such as surface mounting where reflow cannot be performed, current rating is low, and if the rating is increased due to enlargement, the quick-breaking property is poor.

In addition, in the case where a quick-blow fuse element for reflow construction is assumed, in order to avoid melting due to the heat of reflow, it is generally preferred that the fuse unit has a high lead content with a melting point of 300° C. or higher in terms of fusing characteristics. Melting point solder. However, in the RoHS directive, etc., the use of lead-containing solders is only limitedly approved, and it is generally believed that the requirements for lead-free will increase in the future.

That is, as a fuse unit, it is required to have a surface structure that can be reflowed and is excellent in the structure of the fuse element, it is rated and can respond to large currents, and can be quickly interrupted when the rated overcurrent is exceeded Fast fusing of current path.

Therefore, an object of the present invention is to provide a fuse unit that can be surface-mounted and can achieve both rated improvement and fast fusing, as well as a fuse element, a protection element, a short-circuit element, and a switching element using the fuse unit.

In order to solve the above problem, the fuse unit of the present invention has three or more metal layers with different melting points.

In addition, the fuse element of the present invention has a fuse unit in which three or more metal layers having different melting points are stacked; the above-mentioned fuse unit is blown by overcurrent flow exceeding a rating.

Furthermore, the protection element of the present invention includes: an insulating substrate; a heating element formed on or inside the insulating substrate; first and second electrodes provided on the insulating substrate; a heating element extraction electrode, which generates heat Body electrical connection; and a fusible conductor connected from the first electrode to the second electrode via the heating element extraction electrode and connected to the second electrode; the fusible conductor consists of three or more metal layers with different melting points The fuse unit is configured to be melted by the energization of the heating element to block the first and second electrodes.

Moreover, the short-circuit element of the present invention has: an insulating substrate; a heating element formed in On the insulating substrate or inside the insulating substrate; the first and second electrodes are provided adjacent to the insulating substrate; the third electrode is provided on the insulating substrate and electrically connected to the heating element; and a fusible conductor, Crossed between the first and third electrodes; the fusible conductor is composed of a fuse unit in which three or more metal layers with different melting points are stacked, and is melted by the heating of the heating element to make the first 1. A short circuit between the second electrodes interrupts the first and third electrodes.

Moreover, the switching element of the present invention includes: an insulating substrate; first and second heating elements formed on or inside the insulating substrate; first and second electrodes provided adjacent to the insulating substrate; 3 electrodes, provided on the insulating substrate and electrically connected to the first heating element; a first fusible conductor, spanned between the first and third electrodes; a fourth electrode, provided on the insulating substrate and The second heating element is electrically connected; a fifth electrode is provided adjacent to the fourth electrode on the insulating substrate; and a second fusible conductor is bridged from the second electrode to the fifth electrode via the fourth electrode Electrodes; the first and second fusible conductors are composed of a fuse unit in which three or more metal layers with different melting points are stacked; the second fusible conductor is melted by energization of the second heating element, Interrupting between the second and fifth electrodes; melting the first fusible conductor by the energization of the first heating element to short-circuit the first and second electrodes.

According to the present invention, by stacking the high melting point metal layer, the fuse unit will not be fused as a fuse unit even when the assembly temperature such as reflow exceeds the melting temperature of the low melting point metal layer. Therefore, according to the present invention, the fuse unit can be constructed with good efficiency by reflow.

In addition, the fuse unit of the present invention is melted by self-heating or heat generated by a heating element. At this time, the fuse unit erodes the high melting point metal layer through the melted low melting point metal layer, and The high melting point metal layer is dissolved at a temperature lower than its own melting point. Therefore, according to the present invention, the fuse unit can be fused in a short time by the erosion effect of the low melting point metal layer on the high melting point metal layer.

In addition, the fuse unit of the present invention is composed of a low-melting-point metal layer and a low-resistance high-melting-point metal layer, so that the conductor resistance can be greatly reduced, and the current can be rated compared to the conventional chip fuses of the same size. Significantly improved. In addition, it can be thinner than the conventional wafer fuse having the same current rating, and has excellent fast blowability.

Therefore, the fuse unit of the present invention can maintain resistance to high temperature environments such as reflow temperature and low resistance characteristics, compared to a fuse unit composed of laminated fusible conductors of two kinds of metals having different melting points. , Play an excellent fast fusing.

1,10,20,30,40,50,60,70 ‧‧‧ fuse unit

2‧‧‧High melting point metal layer

3‧‧‧First low melting point metal layer

4‧‧‧The second low melting point metal layer

80‧‧‧Fuse element

81‧‧‧Insulated substrate

82‧‧‧First electrode

82a‧‧‧The first external connection electrode

83‧‧‧ 2nd electrode

83a‧‧‧The second external connection electrode

84‧‧‧ Adhesive

85‧‧‧flux

86‧‧‧Protective layer

87‧‧‧flux sheet

88‧‧‧ connection material

89‧‧‧ Covering member

90‧‧‧Protection element

91‧‧‧Insulated substrate

92‧‧‧Insulation

93‧‧‧Fever

94‧‧‧First electrode

94a‧‧‧The first external connection electrode

95‧‧‧ 2nd electrode

95a‧‧‧The second external connection electrode

96‧‧‧Exiting electrode of heating element

97‧‧‧ Covering member

98‧‧‧Protective layer

99‧‧‧Heating body electrode

99a‧‧‧Heating electrode for heating element

100‧‧‧ connection material

101‧‧‧flux sheet

102‧‧‧ Outflow prevention section

104‧‧‧flux

110‧‧‧Short circuit element

111‧‧‧Insulated substrate

112‧‧‧Heating body

113‧‧‧First electrode

113a‧‧‧The first external connection electrode

114‧‧‧ 2nd electrode

114a‧‧‧The second external connection electrode

115‧‧‧3rd electrode

116‧‧‧covering member

117‧‧‧ connection material

118‧‧‧Insulation

119‧‧‧flux

120‧‧‧Extraction electrode of heating element

121‧‧‧Heating body electrode

121a‧‧‧Heating electrode for heating element

122‧‧‧flux sheet

123‧‧‧ switch

124‧‧‧ 4th electrode

125‧‧‧ 2nd fuse unit

126‧‧‧ Outflow prevention section

130‧‧‧Switching element

131‧‧‧Insulation substrate

132‧‧‧The first heating element

133‧‧‧The second heating element

134‧‧‧First electrode

134a‧‧‧The first external connection electrode

135‧‧‧ 2nd electrode

135a‧‧‧Second external connection electrode

136‧‧‧3rd electrode

137‧‧‧ 4th electrode

138‧‧‧ 5th electrode

139‧‧‧covering member

140‧‧‧Insulation

141‧‧‧The first heating element extraction electrode

142‧‧‧The first heating element electrode

142a‧‧‧The first heating element power supply electrode

143‧‧‧Second heating element extraction electrode

144‧‧‧ 2nd heating element electrode

144a‧‧‧Second heating element power supply electrode

145‧‧‧ connection material

146‧‧‧flux sheet

147‧‧‧ Outflow prevention section

150‧‧‧switch

FIG. 1 is a cross-sectional view of the fuse unit of the present invention.

2 is a cross-sectional view of a fuse unit in which a first low-melting-point metal layer is laminated as the outermost layer.

3 is a cross-sectional view of another fuse unit of the present invention formed repeatedly with a predetermined build-up pattern.

FIG. 4 is a cross-sectional view of another fuse unit of the present invention in which a predetermined build-up pattern is repeated and a first low-melting-point metal layer is stacked as the outermost layer.

5 is a cross-sectional view showing other fuse units of the present invention.

6 is a cross-sectional view of another fuse unit in which a second low-melting-point metal layer is laminated as the outermost layer.

7 is a cross section of another fuse unit of the present invention repeatedly formed with a predetermined build-up pattern Face map.

8 is a cross-sectional view of another fuse unit of the present invention that repeats a predetermined build-up pattern and has a second low-melting-point metal layer as the outermost layer.

9 is a cross-sectional view showing a fuse element to which the present invention is applied.

FIG. 10 is a plan view showing the fuse element to which the present invention is applied, omitting the cover member.

11 is a cross-sectional view of a fuse element in which a sheet is impregnated with flux applied to a fuse unit.

FIG. 12 is a cross-sectional view of a fuse element coated with a flux mixed with fibrous materials on a fuse unit.

13 is a circuit diagram of the fuse element, (A) shows before the fuse unit is blown, (B) shows after the fuse unit is blown.

14 is a cross-sectional view showing a state of a fuse unit to which the fuse element of the present invention is blown.

15 is a diagram showing a protection element to which the present invention is applied, (A) is a plan view showing the cover member omitted, and (B) is a cross-sectional view.

16 is a cross-sectional view of a protective element in which a sheet is impregnated with flux applied to a fuse unit.

17 is a cross-sectional view of a protective element coated with flux mixed with fibrous materials on a fuse unit.

FIG. 18 is a circuit diagram showing the protection element to which the present invention is applied.

FIG. 19 is a diagram showing the protection element in a state after the fuse unit is blown, (A) is a plan view shown without the cover member, and (B) is a circuit diagram.

FIG. 20 is a diagram showing a short-circuit element to which the present invention is applied, (A) is a plan view shown without a cover member, and (B) is a cross-sectional view.

21 is a cross-sectional view of a short-circuit element in which a sheet is impregnated with flux applied to a fuse unit.

FIG. 22 is a cross-sectional view of a short-circuit element coated with a flux mixed with fibrous materials on a fuse unit.

Fig. 23 is a circuit diagram of a short-circuit element, (A) shows a state where the switch is cut, and (B) shows a state where the switch is short-circuited.

24 is a cross-sectional view of a short-circuit element showing a state where the insulated first and second electrodes are short-circuited by a molten conductor.

25A is a plan view showing the short-circuit element with the cover member omitted.

25B is a cross-sectional view of a short-circuit element.

FIG. 25C is a cross-sectional view of the two fuse units of the short-circuit element carrying flux sheets, respectively.

FIG. 25D is a cross-sectional view of the sheet impregnated with flux applied to the two fuse units of the short-circuit element.

FIG. 25E is a cross-sectional view of two fuse units of a short-circuit element coated with flux mixed with fibrous materials.

FIG. 25F is a cross-sectional view of two flux units across a short-circuit element coated with a flux mixed with fibers.

FIG. 26A is a plan view showing a switching element to which the present invention is applied, omitting the cover member.

26B is a cross-sectional view of a switching element to which the present invention is applied.

FIG. 27 is a cross-sectional view of the switching element in which the sheet is impregnated with the flux applied to the fuse unit.

FIG. 28 is a cross-sectional view of a switching element coated with a flux mixed with fibrous materials on a fuse unit.

FIG. 29 is a circuit diagram of the switching element before the fuse unit is blown.

FIG. 30 is a plan view showing a state in which the second fuse element of the switching element is melted first without the cover member.

FIG. 31A shows that the cover member is omitted and the second, fourth, and fifth electrodes of the switching element are blocked by the fuse of the fusible conductor being connected, and the first and second electrodes of the insulation are being fuse by the molten conductor Top view of short circuit.

FIG. 31B shows that the cover member is omitted and the second, fourth, and fifth electrodes of the switching element are blocked by the fuse of the fusible conductor being connected, and the first and second electrodes of the insulation are being fuse by the molten conductor Top view of short circuit.

32 is a circuit diagram of the switching element after the fuse unit is blown.

Hereinafter, the fuse unit, the fuse element, the protection element, the short-circuit element, and the switching element to which the present invention is applied will be described in detail while referring to the drawings. In addition, the present invention is not limited to the following embodiments, and of course various changes can be made without departing from the scope of the present invention. In addition, the drawings are only schematics, and the ratios of the dimensions may differ from the actual ones. The specific dimensions should be judged in consideration of the following description. In addition, the drawings also naturally include parts having different dimensional relationships or ratios.

[Fuse Unit]

First, the fuse unit to which the present invention is applied will be explained. The fuse unit 1 to which the present invention is applied is used as a fusible conductor of a fuse element, a protection element, a short-circuit element, and a switching element described later, by The self-heating (Joule heat) that exceeds the rated current flows and is fused, or is fused by the heating of the heating body. The fuse unit 1 has three or more metal layers with different melting points, for example, as shown in FIG. 1, it has a high melting point metal layer 2, a first low melting point metal layer 3 having a melting point lower than the high melting point metal layer 2, and a melting point The second low-melting-point metal layer 4 lower than the first low-melting-point metal layer 3 is formed in, for example, a rectangular plate shape.

The high-melting-point metal layer 2 is preferably made of, for example, Ag, Cu, or an alloy containing Ag or Cu as a main component, and has a high temperature that does not melt when the fuse unit 1 is mounted on an insulating substrate by a reflow furnace Melting point.

The first low-melting-point metal layer 3 is preferably a material that uses Sn or an alloy containing Sn as a main component and is generally called "lead-free solder." The melting point of the first low-melting-point metal layer 3 does not have to be higher than the temperature of the reflow furnace, and it may also melt at about 200°C.

The second low-melting-point metal layer 4 is preferably Bi, In, or an alloy containing Bi or In as a main component. The melting point of the second low-melting-point metal layer 4 is lower than that of the first low-melting-point metal layer 3, for example, melting starts at 120°C to 140°C.

The fuse unit 1 is formed by laminating three or more metal layers with different melting points, which can make the fuse element, protection element, short-circuit element, and switching element excellent in the construction of the insulating substrate, Each element of the wire unit 1 improves the structure of the external circuit board. In addition, the fuse unit 1 can achieve rated improvement and fast fusing in each element.

That is, the fuse unit 1 is provided with the high-melting-point metal layer 2 and is exposed to high heat above the melting point of the first and second low-melting-point metal layers 3, 4 in a short time even by an external heat source such as a reflow furnace In the case of environment, it can also prevent fusing or deformation, and prevent the reduction of fusing characteristics caused by initial interruption, initial short circuit or rating change. Therefore, the fuse unit 1 can be constructed by reflow Good efficiency realizes the construction of the fuse element and other components on the insulating substrate, and the fuse element and other components on the external circuit substrate, so that the structure is improved.

In addition, since the fuse unit 1 is formed by stacking a high-melting-point metal layer 2 with low resistance, it can greatly reduce the conductor resistance compared to the conventional fusible conductor using lead-based high-melting-point solder, compared to the same size Conventional chip fuses, etc., can greatly increase the current rating. In addition, it can be thinner than the conventional wafer fuse having the same current rating, and has excellent fast blowability.

Furthermore, since the fuse unit 1 has a first low-melting-point metal layer 3 having a melting point lower than the high-melting-point metal layer 2 and a second low-melting-point metal layer 4 having a melting point lower than the first low-melting-point metal layer 3, it can be borrowed The self-heating or the heating of the heating element caused by the overcurrent melts from the melting point of the second low-melting-point metal layer 4, which improves the rapid fusing characteristic. For example, when the second low-melting-point metal layer 4 is composed of a Sn-Bi-based alloy or an In-Sn-based alloy, etc., the fuse unit 1 starts to melt at a low temperature around 140°C or 120°C. Next, by melting the first and second low-melting-point metal layers 3 and 4 to erode the high-melting-point metal layer 2 (solder erosion), the high-melting-point metal layer 2 is melted at a temperature lower than the melting point. Therefore, the fuse unit 1 can utilize the erosive effect of the first and second low-melting-point metal layers 3 and 4 on the high-melting-point metal layer 2 to improve the rapid fusing.

[Laminated structure of fuse unit]

Here, as shown in FIG. 1, the fuse unit 1 preferably has a high melting point metal layer 2 laminated between the first low melting point metal layer 3 and the second low melting point metal layer 4. The fuse unit 1 sandwiches the high-melting-point metal layer 2 by the first and second low-melting-point metal layers 3 and 4 having different melting points, and the high-melting-point metal starts from the lower temperature of the second low-melting-point metal layer 4 The erosion of one side of the layer 2 is followed by the erosion of the high melting point metal layer 2 from both sides at the temperature of the first low melting point metal layer 3.

Thereby, the fuse unit 1 can have resistance to high temperature environments such as reflow temperature and At the same time, the fast fusing characteristic is improved. That is, a fuse unit composed of a low-melting-point metal layer and a high-melting-point metal layer such as Ag composed of a general lead-free solder with a melting point of around 220°C must be resistant to high-temperature environments such as reflow temperature. As the thickness of the high melting point metal layer is increased, the fusing time becomes longer.

In addition, if the low-melting-point metal layer is formed of a cheaper Sn/Bi-based alloy in order to shorten the fuse unit fusing time, the resistance value becomes higher and the rating cannot be improved.

In this regard, the fuse unit 1 is based on the first low-melting-point metal layer 3 in which Sn or an alloy containing Sn as a main component can be very suitably used, and Bi, In or an alloy containing Bi or In can be very suitably used and A high-melting-point metal layer 2 is stacked between the second low-melting-point metal layer 4 and the second low-melting-point metal layer 4 having a melting point lower than that of the first low-melting-point metal layer 3. In this way, in the fuse unit 1, even if the high-melting-point metal layer 2 has a thickness that is resistant to high-temperature environments such as the reflow temperature, the high-melting point can be reduced by the first and/or second low-melting-point metal layers 3 and 4 The metal layer 2 is eroded from both sides and can be quickly fused.

In addition, the fuse unit 1 can maintain a low resistance by including the first low-melting-point metal layer 3 that can use Sn or an alloy containing Sn as a main component, and can also use Bi and In very appropriately by having Or a second low-melting-point metal layer 4 containing an alloy of Bi or In and having a melting point lower than that of the first low-melting-point metal layer 3 can be melted from a low temperature and improve the rapid fusing property.

Furthermore, the fuse unit 1 has a high melting point metal layer 2 between the first low melting point metal layer 3 and the second low melting point metal layer 4 having a melting point lower than that of the first low melting point metal layer 3. When a part of the metal layer 2 is dissolved and the first low-melting-point metal layer 3 and the second low-melting-point metal layer 4 are mixed, the melting point of the first low-melting-point metal layer 3 is lowered, and the melting speed is accelerated, that is, the quick fusing property can be further improved.

In addition, the fuse unit 1 is preferably composed of a high melting point metal layer 2 and a first low melting point The metal layer 3 and the second low-melting-point metal layer 4 are stacked with four or more layers. At this time, as shown in FIG. 1, the fuse unit 1 may also deposit four layers in the order of the first low melting point metal layer 3, the high melting point metal layer 2, the second low melting point metal layer 4, and the high melting point metal layer 2 from the lower layer. The fuse unit shown in FIG. 1 can be quickly fused by stacking a high-melting-point metal layer 2 between the first and second low-melting-point metal layers 3 and 4.

In addition, the fuse unit 1 may also use the first low-melting-point metal layer 3 as the connecting material for connecting the electrodes of each element of a fuse element, a protection element, a short-circuit element, and a switching element described later. That is, the fuse unit 1 may also be connected to the electrodes of each element through the first low-melting-point metal layer 3.

In addition, the fuse unit 1 can be improved by assembling the inner layer provided between the pair of high melting point metal layers 2 as the second low melting point metal layer 4 and the outer layer as the high melting point metal layer 2. The electrical system of each element, such as a fuse element, has resistance to lightning surges (impulse resistance) when an abnormally high voltage is applied momentarily. That is, the fuse unit 1 does not blow until a current of 100 A flows for a few msec, for example. At this point, since a large current flowing in a very short time flows through the surface layer of the conductor (skin effect), and the fuse unit 1 is provided with a high-melting-point metal layer 2 such as Ag plating having a low resistance value as an outer layer, the lightning is caused by lightning The current applied by the surge easily flows, which can prevent melting due to self-heating. Therefore, the fuse unit 1 can greatly improve the resistance to lightning surges compared to fuses formed by conventional solder alloys.

[Manufacturing method]

The fuse unit 1 can be manufactured by forming a high-melting-point metal 2 on the surfaces of the first and second low-melting-point metal layers 3 and 4 using a plating technique. The fuse unit 1 can be manufactured with high efficiency by applying Ag plating to the surface of the elongated solder foil, for example, and can be easily used by cutting according to the size during use.

In addition, the fuse unit 1 can also be manufactured by laminating the low melting point metal foil constituting the first and second low melting point metal layers 3 and 4 and the high melting point metal foil constituting the high melting point metal layer 2. The fuse unit 1 is, for example, sandwiched between two rolled Cu foils or Ag foils, which are also rolled to form the second low-melting-point metal layer 4 of the solder foil, and then laminated on a high-melting-point metal layer 2 to constitute the first The solder foil of the low-melting-point metal layer 3 is pressed and manufactured. In this case, the low melting point metal foil is preferably a softer material with a higher melting point metal foil. As a result, the uneven thickness can be absorbed and the low-melting-point metal foil and the high-melting-point metal foil can be closely adhered without a gap. In addition, since the low melting point metal foil can be thinned by pressing, the thickness can be made thicker first. When the low melting point metal foil exceeds the end surface of the fuse unit due to the pressing, it is preferable to cut off to adjust the shape.

In addition, the fuse unit 1 can also form a fusion of the first and second low-melting-point metal layers 3 and 4 and the high-melting-point metal layer 2 by thin film forming techniques such as evaporation or other well-known layering techniques.丝单元1。 Silk unit 1.

In addition, when a high melting point metal layer 2 is used as the outermost layer, the fuse unit 1 may further form an oxidation prevention film (not shown) on the surface of the outermost high melting point metal layer 2. The fuse unit 1 is further covered with an oxidation prevention film by the outermost high-melting-point metal layer 2, and can also prevent the oxidation of Cu even when Cu plating or Cu foil is formed as the high-melting-point metal layer 2. Therefore, the fuse unit 1 can prevent the fusing time from becoming longer due to the oxidation of Cu, and can be fused in a short time.

In addition, the fuse unit 1 can use a cheap but easily oxidized metal such as Cu as the high-melting-point metal layer 2 and can be formed without using an expensive material such as Ag.

For the oxidation prevention film of the high melting point metal, the same material as the first and second low melting point metal layers 3 and 4 can be used, for example, lead-free solder containing Sn as a main component can be used. Also, oxidation prevention The stop film can be formed by applying tin plating to the surface of the high melting point metal layer 2. In addition, the oxidation prevention film can also be formed by Au plating or pre-flux.

Furthermore, the fuse unit to which the present invention is applied may also be stacked in the order of the first low-melting-point metal layer 3, the high-melting-point metal layer 2, the second low-melting-point metal layer 4, and the high-melting-point metal layer 2 as shown in FIG. 2, and The first low-melting-point metal layer 3 is laminated as the outermost layer. In the fuse unit 10 shown in FIG. 2, the inner layer provided between the pair of high-melting-point metal layers 2 is the second low-melting-point metal layer 4, the outer layer is the high-melting-point metal layer 2, and the outermost layer is provided. The first low-melting-point metal layer 3 is formed, and a pair of high-melting-point metal layers 2 are stacked between the first and second low-melting-point metal layers 3 and 4.

In addition, as shown in FIG. 3, the fuse unit to which the present invention is applied can also be laminated by repeatedly stacking the first low-melting-point metal layer 3, the high-melting-point metal layer 2, the second low-melting-point metal layer 4, and the high-melting-point metal layer 2. Pattern to form. The fuse unit 20 shown in FIG. 3 can reduce the resistance due to the increase in the thickness of the fuse unit and suppress the deformation during reflow by maintaining the fast fusing property by repeating the stacked pattern.

In other words, in order to lower the resistance and increase the rated current, the fuse unit must thicken the high-melting-point metal layer or thicken the low-melting-point metal. If thickening the high melting point metal layer, in addition to lowering the resistance, it can prevent deformation or fusing during reflow, and improve the resistance to high temperature environments such as reflow temperature, but on the other hand, it will damage the fast fusing. In addition, thickening the low-melting-point metal layer will accelerate corrosion and impair the resistance to high-temperature environments. Therefore, the fuse unit 20 can maintain rapid fusing by repeating the build-up pattern, and at the same time ensure the desired thickness to increase the rating due to the reduction in resistance and to improve the resistance to high temperature environments. In addition, although the fuse unit 20 stacks 8 layers by repeating the stacking pattern, the fuse unit of the present invention can also be stacked by stacking 8 or more layers by repeating the stacking pattern.

In addition, as shown in FIG. 4, the fuse unit of the present invention may be used to repeat the stacked pattern of the first low melting point metal layer 3, the high melting point metal layer 2, the second low melting point metal layer 4, and the high melting point metal layer 2 and The first low-melting-point metal layer 3 is laminated as the outermost layer. The fuse unit 30 shown in FIG. 4 is formed by laminating 8 layers by repeating the lamination pattern, the first low melting point metal layer 3 is laminated as the outermost layer, and all the high melting point metal layers 2 are laminated on the first and second low melting points Between metal layers 3,4.

In addition, as shown in FIG. 5, the fuse unit of the present invention may be stacked from the lower layer in the order of the second low melting point metal layer 4, the high melting point metal layer 2, the first low melting point metal layer 3, and the high melting point metal layer 2. Four floors. The fuse unit 40 shown in FIG. 5 can be quickly fused by stacking a high melting point metal layer 2 between the first and second low melting point metal layers 3 and 4 in the same manner as the fuse unit 1 described above. .

In addition, the fuse unit 40 may also use the second lowest melting point metal layer 4 as a connection material connected to the electrodes of each element of a fuse element, a protection element, a short circuit element, and a switching element described later. That is, the fuse unit 40 may also be connected to the electrode of each element through the second low-melting-point metal layer 4.

Furthermore, as shown in FIG. 6, the fuse unit to which the present invention is applied may be stacked in the order of the second low-melting-point metal layer 4, the high-melting-point metal layer 2, the first low-melting-point metal layer 3, and the high-melting-point metal layer 2. And the second low melting point metal layer 4 is laminated as the outermost layer. In the fuse unit 50 shown in FIG. 6, the inner layer provided between the pair of high melting point metal layers 2 is set as the first low melting point metal layer 3, the outer layer is set as the high melting point metal layer 2, and the outermost layer is set The second low-melting-point metal layer 4 is formed, and a pair of high-melting-point metal layers 2 are stacked between the first and second low-melting-point metal layers 3 and 4.

In addition, as shown in FIG. 7, the fuse unit to which the present invention is applied may be repeated by repeating the second low melting point metal layer 4, the high melting point metal layer 2, the first low melting point metal layer 3, and the high melting point metal layer 2 Layered pattern. The fuse unit 60 shown in FIG. 7 is designed to reduce the resistance due to an increase in the thickness of the fuse unit while maintaining the fast fusing performance as in the fuse units 20 and 30 described above by repeating the laminated pattern. And suppress the deformation caused by the increase in rigidity during reflow. In addition, although the fuse unit 60 stacks 8 layers by repeating the stacking pattern, the fuse unit of the present invention can also be stacked by stacking 8 or more layers by repeating the stacking pattern.

In addition, as shown in FIG. 8, the fuse unit to which the present invention is applied can also repeat the stacked pattern of the second low melting point metal layer 4, the high melting point metal layer 2, the first low melting point metal layer 3, and the high melting point metal layer 2 and The second low melting point metal layer 4 is laminated as the outermost layer. The fuse unit 70 shown in FIG. 8 is formed by laminating 8 layers by repeating the lamination pattern, and the second low melting point metal layer 4 is laminated as the outermost layer, and all the high melting point metal layers 2 are laminated at the first and second low melting points Between metal layers 3,4.

In addition, as described above, the fuse unit 1,10,20,30,40,50,60,70 can be very suitably used as Bi, In or an alloy containing Bi or In as the second low melting point metal layer Metal, but the In resistivity is lower than Sn and it is a rare metal and an expensive material. Therefore, the overall judgment from the manufacturing cost, the ease of material acquisition, etc. is compared to the fuse unit 1, 10 shown in Figures 1 to 4. 20, 30, the configuration of the fuse units 40, 50, 60, 70 shown in Figs. 5-8 should be better.

In addition, in the above-mentioned fuse units 1, 10, 20, 30, 40, 50, 60, and 70, it is preferable that the volume of the first low-melting-point metal layer 3 is larger than the volume of the higher-melting-point metal layer 2. The fuse unit 1, 10, 20, 30, 40, 50, 60, 70 can effectively increase the volume of the first low-melting-point metal layer 3 in a short time by the erosion of the high-melting-point metal layer 2 Fuse. Similarly, in the fuse unit 1, 10, 20, 30, 40, 50, 60, 70, it is preferable to set the volume of the second low melting point metal layer 4 to be larger than the volume of the higher melting point metal layer 2.

Next, the use of the above fuse unit 1,10,20,30,40,50,60,70 is explained Fuse element, protection element, short circuit element, switching element. In addition, in the following description, although each element of the fuse unit 1 is described, it is of course also possible to use the fuse units 1, 10, 20, 30, 40, 50, 60, 70.

[Fuse element]

The fuse element 80 to which the present invention is applied includes an insulating substrate 81, a first electrode 82 and a second electrode 83 provided on the insulating substrate 81, and a fuse unit 1 as shown in FIG. 9. The fuse unit 1 spans the first It is constructed between the second electrodes 82 and 83 and is fused by self-heating by being energized with a current exceeding the rated current, thereby blocking the current path between the first electrode 82 and the second electrode 83.

The insulating substrate 81 is formed into a square shape using insulating members such as alumina, glass ceramics, mullite, and zirconia. In addition, as the insulating substrate 81, a material such as a glass epoxy substrate, a phenol substrate, or the like for printed wiring boards may be used.

First and second electrodes 82 and 83 are formed on opposite ends of the insulating substrate 81. The first and second electrodes 82, 83 are each formed by conductive patterns such as Ag or Cu wiring, and Sn plating, Ni/Au plating, Ni/Pd plating, Ni/ Protective layer 86 such as Pd/Au plating. In addition, the first and second electrodes 82, 83 are continuous from the front surface 81a of the insulating substrate 81 via a castellation to the first and second external connection electrodes 82a, 83a formed on the back surface 81b. The fuse element 80 is mounted on the current path of the circuit board through the first and second external connection electrodes 82a and 83a formed on the back surface 81b.

The first and second electrodes 82 and 83 are connected to the fuse unit 1 through a connecting material 88 such as solder.

As described above, since the fuse unit 1 is provided with the high-melting-point metal layer 2, the resistance to a high-temperature environment is improved, so it is excellent in structurability, and is mounted on the first through the connecting material 88 After the second electrode 82, 83, it can be easily connected by reflow welding or the like. In addition, the fuse unit 1 may also be connected to the first and second electrodes 82, 83 using the first low-melting-point metal layer 3 or the second low-melting-point metal layer 4 provided in the lowermost layer as a connecting material.

[Construction status]

Next, the construction state of the fuse unit 1 will be described. In the fuse element 80, as shown in FIG. 9, the fuse unit 1 is constructed by being separated from the surface 81 a of the insulating substrate 81.

On the other hand, in the fuse element in which the fuse unit is formed on the surface of the insulating substrate by printing, and the fuse unit is in contact with the surface of the insulating substrate, the molten metal in the fuse unit between the first and second electrodes will It adheres to the insulating substrate and causes leakage. For example, in a fuse element in which a fuse unit is formed by printing Ag paste on a ceramic substrate, ceramic and silver are sintered and infiltrated, and remain between the first and second electrodes. Therefore, the leakage current flows between the first and second electrodes due to the molten residue of the fuse unit, and the current path cannot be completely blocked.

In this regard, in the fuse element 80, the fuse unit 1 is formed separately from the insulating substrate 81, and is formed separately from the surface 81a of the insulating substrate 81. Therefore, in the fuse element 80, even when the fuse unit 1 is melted, penetration of molten metal into the insulating substrate 81 does not occur and can be introduced into the first and second electrodes 82, 83, so that the first , The second electrode 82,83 is insulated.

[Flux sheet]

In addition, in the fuse element 80, in order to prevent the oxidation of the high-melting-point metal layer 2 or the first and second low-melting-point metal layers 3, 4 and to remove the oxides at the time of fusing and to improve the fluidity of the solder, the fuse unit 1. Apply flux on the surface or back of 1. Furthermore, as shown in FIG. 9, the flux sheet 87 may be arranged all over the outermost layer on the fuse unit 1. Flux sheet 87 is a flux for fluid or semi-fluid The agent is impregnated and held in a sheet-shaped support, for example, the impregnated flux is impregnated with a non-woven fabric or a mesh-shaped fabric.

As shown in FIG. 10, the flux sheet 87 preferably has an area larger than the surface area of the fuse unit 1. As a result, the fuse unit 1 is completely covered by the flux sheet 87, and even when the volume is expanded due to melting, the rapid removal of the oxide by the flux and the improvement of wettability can be reliably achieved.

By arranging the flux sheet 87, the flux can also be kept on the entire surface of the fuse unit 1 during the heat treatment step when the fuse unit 1 is assembled or when the fuse element 80 is assembled. In actual use, the wettability of the first and second low-melting-point metal layers 3, 4 (such as solder) can be improved, and the oxides during the dissolution of the first and second low-melting-point metals can be removed. ) The erosive effect improves the fast fusing.

Moreover, by arranging the flux sheet 87, even if an oxidation preventing film such as lead-free solder mainly composed of Sn is formed on the surface of the outermost refractory metal layer 2, the oxide of the oxidation preventing film can be removed, which is effective To prevent the oxidation of the high-melting-point metal layer 2 and maintain and improve the fast fusing.

In addition, the fuse element 80 can also replace the flux sheet 87. As shown in FIG. 11, after applying the flux 85a to the outermost layer of the fuse unit 1, a non-woven fabric or a mesh-like cloth is placed on the flux 85a, and Impregnate the flux. In addition, as shown in FIG. 12, the fuse element 80 may replace the flux sheet and apply the flux 85 b mixed with the fibrous material to the entire outermost layer of the fuse unit 1. The flux 85b can improve the viscosity by mixing with fibrous materials, and it is not easy to flow in a high-temperature environment. The fuse unit 1 can comprehensively seek to remove oxides and improve wettability during fusing. In addition, as the fibrous material mixed with the flux 85b, for example, non-woven fiber, glass Glass fiber and other fibers with insulation and heat resistance.

In addition, although the fuse unit 1 can be connected to the first and second electrodes 82, 83 by reflow welding as described above, in addition, the fuse unit 1 can also be connected to the first electrode by ultrasonic welding. On the first and second electrodes 82, 83.

[Cover member]

In addition, in the fuse element 80, a cover member 89 that protects the inside and prevents scattering of the melted fuse unit 1 is mounted on the surface 81a of the insulating substrate 81 on which the fuse unit 1 is provided. The covering member 89 can be formed by insulating members such as various engineering plastics and ceramics, and is connected through an insulating adhesive 84. In the fuse element 80, since the fuse unit 1 is covered by the covering member 89, when self-heating caused by arc discharge due to overcurrent is interrupted, molten metal is also caught by the covering member 89 and can be prevented Scattered around.

In addition, the covering member 89 has a protrusion 89b extending from the top surface 89a toward the insulating substrate 81 to at least the side surface of the flux sheet 87. Since the covering member 89 restricts the movement of the side surface of the flux sheet 87 by the protrusion 89b, the position of the flux sheet 87 can be prevented from shifting. That is, the protruding portion 89b is provided to maintain the size of the predetermined gap compared to the size of the flux sheet 87, and is provided corresponding to the position where the flux sheet 87 should be maintained. In addition, the protruding portion 89b may be formed as a wall surface that wraps around the side surface of the flux sheet 87 and may be partially protruded.

In addition, the covering member 89 is constituted by a predetermined interval between the flux sheet 87 and the top surface 89a. The reason for this configuration is that when the fuse unit 1 is melted, it is necessary to have a gap where the melted fuse unit 1 presses the flux sheet 87 upward.

Therefore, in the covering member 89, the height of the internal space of the covering member 89 (the height up to the top surface 89a) is configured to be higher than the molten fuse on the surface 81a of the insulating substrate 81 The sum of the height of the unit 1 and the thickness of the flux sheet 87 is still large.

[Circuit configuration]

This fuse element 80 has the circuit configuration shown in FIG. 13(A). The fuse element 80 is assembled in an external circuit through the first and second external connection electrodes 82a and 83a to be assembled in the current path of the external circuit. The fuse element 80 does not blow due to self-heating while the predetermined rated current flows through the fuse unit 1. Next, after the fuse element 80 is energized after exceeding the rated overcurrent, the fuse unit 1 is fused due to self-heating, interrupting the first and second electrodes 82, 83, thereby interrupting the current of the external circuit Path (Figure 13(B)).

At this time, the fuse unit 1 has the first low melting point metal layer 3 having a melting point lower than the high melting point metal layer 2 and the second low melting point metal layer 4 having a melting point lower than the first low melting point metal layer 3 as described above. Therefore, the self-heating caused by the overcurrent begins to melt from the melting point of the second low-melting-point metal layer 4 and begins to erode the high-melting-point metal layer 2. Therefore, the fuse unit 1 can use the erosion of the first and second low-melting-point metal layers 3 and 4 to the high-melting-point metal layer 2, and the high-melting-point metal layer 2 is melted at a temperature lower than its melting point, quickly Fuse.

Furthermore, as shown in FIG. 14, the molten metal of the fuse unit 1 is divided to the left and right by the physical pull-in action of the first and second electrodes 82, 83, so the first can be quickly and surely blocked And the current path between the second electrodes 82,83.

[Protection element]

Next, the protection element using the fuse unit 1 will be described. As shown in FIGS. 15(A) and (B), the protection element 90 to which the present invention is applied includes an insulating substrate 91, a heating element 93 laminated on the insulating substrate 91 and covered by the insulating member 92, and first substrates formed on both ends of the insulating substrate 91 The first electrode 94 and the second electrode 95 are laminated on the insulating member 91 to overlap the heating element 93 and electrically connected to the heating element 93. The heating body extraction electrode 96 and both ends are respectively connected to the first and second electrodes 94, 95 and the center portion is connected to the fuse unit 1 of the heating body extraction electrode 96. In addition, the protective element 90 is mounted on the insulating substrate 91 with a cover member 97 that protects the inside.

The insulating substrate 91 is formed into a square shape using insulating members such as alumina, glass ceramic, mullite, and zirconia, similar to the insulating substrate 81 described above. In addition, as the insulating substrate 91, a material such as a glass epoxy substrate and a phenol substrate may be used for printed wiring boards.

First and second electrodes 94 and 95 are formed on opposite ends of the insulating substrate 91. The first and second electrodes 94 and 95 are formed by conductive patterns such as Ag or Cu wiring. The first and second electrodes 94, 95 are continuous from the first and second external connection electrodes 94a, 95a formed on the back surface 91b from the front surface 91a of the insulating substrate 91 via a castle-shaped contact. The protection element 90 is assembled into the current path formed on the circuit board by connecting the first and second external connection electrodes 94a, 95a formed on the back surface 91b to the connection electrodes provided on the circuit board on which the protection element 90 is constructed Part.

The heating element 93 is an electrically conductive member that generates heat when energized, and is made of, for example, nickel chromium, W, Mo, Ru, or a material including these. The heating element 93 can be formed by forming a pattern on the insulating substrate 91, firing, etc., by using a screen printing technique to mix a powder of these alloys or compositions, compounds, and a resin binder into a paste.

In the protection element 90, the heating element 93 is covered with the insulating member 92, and the heating element extraction electrode 96 is formed so as to face the heating element 93 via the insulating member 92. The heating element extraction electrode 96 is connected to the fuse unit 1, whereby the heating element 93 overlaps the fuse unit 1 via the insulating member 92 and the heating element extraction electrode 96. The insulating member 92 is for seeking the heating element 93 It is provided for protection and insulation, and transmits the heat of the heating element 93 to the fuse unit 1 with good efficiency, and is composed of, for example, a glass layer.

In addition, the heating element 93 may be formed inside the insulating member 92 laminated on the insulating substrate 91. In addition, the heating element 93 may be formed on the back surface 91b opposite to the surface 91a of the insulating substrate 91 on which the first and second electrodes 94, 95 are formed, or may be formed on the surface 91a of the insulating substrate 91 with the first and second The electrodes 94, 95 are formed adjacent to each other. In addition, the heating element 93 may be formed inside the insulating substrate 91.

In addition, one end of the heating element 93 is connected to the heating element extraction electrode 96 and the other end is connected to the heating element electrode 99. The heating element extraction electrode 96 has a lower layer portion 96a formed on the surface 91a of the insulating substrate 91 and connected to the heating element 93, and an upper layer portion opposed to the heating element 93 and laminated on the insulating member 92 and connected to the fuse unit 1 96b. Thereby, the heating element 93 is electrically connected to the fuse unit 1 through the heating element extraction electrode 96. In addition, the heating element extraction electrode 96 is arranged to face the heating element 93 via the insulating member 92, so that the fuse unit 1 can be melted, and the molten conductor can be easily aggregated.

The heating element electrode 99 is formed on the front surface 91a of the insulating substrate 91 and continues to the heating element power supply electrode 99a formed on the back surface 91b of the insulating substrate 91 via the castellated contact.

The protection element 90 is connected to the fuse unit 1 so as to extend from the first electrode 94 to the second electrode 95 via the heating element extraction electrode 96. The fuse unit 1 is connected to the first and second electrodes 94, 95 and the heating element extraction electrode 96 through a connection material 100 such as solder.

As described above, since the fuse unit 1 is provided with the high-melting-point metal layer 2, the resistance to high-temperature environments is improved, so it has excellent structural properties and can be mounted on the first and second electrodes 94 through the connection material 100. After the 95 and the heating element are drawn out on the electrode 96, it can be easily connection. In addition, the fuse unit 1 may also use the first low-melting-point metal layer 3 or the second low-melting-point metal layer 4 provided in the lowermost layer as a connecting material to connect to the first and second electrodes 94, 95 and the heating element引出 electrode 96.

[Flux sheet]

In addition, in the protection element 90, in order to prevent the oxidation of the high-melting-point metal layer 2 or the first and second low-melting-point metal layers 3, 4 and to remove the oxide at the time of fusing and improve the fluidity of the solder, the fuse unit 1 Flux is applied on the surface or back surface. Furthermore, as shown in FIG. 15, the flux sheet 101 may be arranged all over the outermost layer on the fuse unit 1. The flux sheet 101 is the same as the flux sheet 87 described above, in which the flux of the fluid or semi-fluid is impregnated and held in a sheet-shaped support, for example, the flux is impregnated into a non-woven fabric or mesh-like fabric Successor.

The flux sheet 101 preferably has a larger area than the surface area of the fuse unit 1. As a result, the fuse unit 1 is completely covered by the flux sheet 101, and even when the volume is expanded due to melting, the rapid removal of the oxide by the flux and the improvement of wettability can be reliably achieved.

By arranging the flux sheet 101, the flux can also be kept in the entirety of the fuse unit 1 during the heat treatment step when the fuse unit 1 is assembled or when the protection element 90 is assembled, and is actually used in the protection element 90 Can improve the wettability of the first and second low-melting-point metal layers 3, 4 (such as solder), and remove the oxides during the dissolution of the first and second low-melting-point metals, using the high melting point metal (such as Ag) The erosion effect improves the fast fusing.

Furthermore, by arranging the flux sheet 101, even if an oxidation preventing film such as lead-free solder mainly composed of Sn is formed on the surface of the outermost refractory metal layer 2, the oxide of the oxidation preventing film can be removed, which is effective To prevent the oxidation of the high-melting-point metal layer 2 and maintain and improve the fast fusing.

In addition, the protection element 90 can also replace the flux sheet 101. As shown in FIG. 16, after applying the flux 104a to the outermost layer of the fuse unit 1, a non-woven fabric or mesh-like cloth is arranged on the flux 104a, and The flux 104a is impregnated. Furthermore, as shown in FIG. 17, the protective element 90 may replace the flux sheet and apply the flux 104b mixed with the fibrous material to the entire outermost layer of the fuse unit 1. The flux 104b can improve the viscosity by mixing with fibrous materials, and it is not easy to flow in a high-temperature environment, so that the fuse unit 1 can comprehensively remove oxides and improve wettability during fusing. In addition, as the fibrous material mixed with the flux 104b, for example, nonwoven fabric fibers, glass fibers, and other fibers having insulation and heat resistance can be suitably used.

In addition, the first and second electrodes 94, 95, the heating element extraction electrode 96, and the heating element electrode 99 are formed by a conductive pattern such as Ag or Cu, and Sn plating, Ni/Au are appropriately formed on the surface Protective layer 98 for plating, Ni/Pd plating, Ni/Pd/Au plating, etc. This prevents surface oxidation and suppresses the first and second electrodes 94 of the first and second low-melting metal layers 3 and 4 of the fuse unit 1 or the connecting material 100 such as solder for connecting the fuse unit 1 to the first and second electrodes 94 , 95 and the heating element lead to the erosion of the electrode 96.

Further, at the first and second electrodes 94, 95, an outflow preventing portion 102 made of an insulating material such as glass for preventing the outflow of the molten conductor of the fuse unit 1 or the connection material 100 of the fuse unit 1 is formed.

[Cover member]

In addition, the protective element 90 is provided with a cover member 97 that protects the inside and prevents the molten fuse unit 1 from scattering on the surface 91 a of the insulating substrate 91 provided with the fuse unit 1. The covering member 97 can be formed by insulating members such as various engineering plastics and ceramics. In the protective element 90, since the fuse unit 1 is covered by the covering member 97, the molten metal is caught by the covering member 97 and can be prevented Stop flying around.

In addition, the covering member 97 has a protrusion 97b extending from the top surface 97a toward the insulating substrate 91 to at least the side surface of the flux sheet 101. Since the covering member 97 restricts the movement of the side surface of the flux sheet 101 by the protrusion 97b, the position of the flux sheet 101 can be prevented from shifting. That is, the protruding portion 97b is compared with the size of the flux sheet 101 to maintain the size of the predetermined gap, and is provided corresponding to the position where the flux sheet 101 should be maintained. In addition, the protruding portion 97b may be formed as a wall surface that wraps around the side surface of the flux sheet 101 and may be partially protruded.

In addition, the covering member 97 is constituted by a predetermined interval between the flux sheet 101 and the top surface 97a. The reason for this configuration is that when the fuse unit 1 is melted, it is necessary to have a gap where the melted fuse unit 1 presses the flux sheet 101 upward.

Therefore, in the covering member 97, the height of the internal space of the covering member 97 (the height up to the top surface 97a) is configured to be higher than the height of the molten fuse unit 1 on the surface 91a of the insulating substrate 91 and the flux sheet The sum of the thickness of 101 is still large.

This protection element 90 is formed with an energizing path to the heating element 93 that reaches the heating element power supply electrode 99a, the heating element electrode 99, the heating element 93, the heating element extraction electrode 96, and the fuse unit 1. In the protection element 90, the heating element electrode 99 is connected to an external circuit that energizes the heating element 93 through the heating element power supply electrode 99a, and the energization between the heating element electrode 99 and the fuse unit 1 is controlled by the external circuit.

In addition, the protective element 90 is connected to the heating element extraction electrode 96 by the fuse unit 1 to form a part of the energizing path to the heating element 93. Therefore, after the fuse unit 1 melts to cut off the connection with the external circuit, the current supply path to the heating element 93 is also cut off, so that the heat generation can be stopped.

[Circuit diagram]

The protection element 90 to which the present invention is applied has the circuit configuration shown in FIG. That is, the protection element 90 is the fuse unit 1 connected in series between the first and second external connection electrodes 94a, 95a by the electrode 96 drawn through the heating element, and generates heat by being energized through the connection point of the fuse unit 1 The circuit configuration of the heating element 93 that melts the fuse unit 1. In the first and second electrodes 94 and 95 of the protection element 90 and the heating element electrode 99, the first and second external connection electrodes 94a and 95a and the heating element power supply electrode 99a are respectively connected to the external circuit board. Thereby, the protection element 90 and the fuse unit 1 pass through the first and second electrodes 94 and 95 in series with the current path of the external circuit, and the heating element 93 passes through the heating element electrode 99 and is connected to the current control element provided in the external circuit.

[Fuse Step]

The protection element 90 constituted by such a circuit configuration causes the heating element 93 to be energized by the current control element provided in the external circuit when it is necessary to interrupt the current path of the external circuit. Thereby, the protection element 90 melts the fuse unit 1 assembled on the current path of the external circuit by the heat of the heating element 93, and as shown in FIG. 19(A), by the fuse unit 1’s molten conductor The heating element drawn electrode close to the high wettability leads to the electrode 96 and the first and second electrodes 94, 95 to blow the fuse unit 1. As a result, the fuse unit 1 can surely fuse the first electrode 94 to the heating element extraction electrode 96 to the second electrode 95 (FIG. 19(B) ), and interrupt the current path of the external circuit. In addition, when the fuse unit 1 is blown, the power supply to the heating element 93 is also stopped.

At this time, the fuse unit 1 has the first low melting point metal layer 3 having a melting point lower than the high melting point metal layer 2 and the second low melting point metal layer 4 having a melting point lower than the first low melting point metal layer 3 as described above. Therefore, the melting point of the second low-melting-point metal layer 4 starts to melt, and the high-melting-point metal layer 2 begins to erode. Therefore, the fuse unit 1 can use the first and second low-melting-point metal layers 3 and 4 to be high The erosion effect of the melting point metal layer 2 is that the high melting point metal layer 2 is melted at a temperature lower than the melting temperature and quickly melts.

[Short circuit element]

Next, the short-circuit element using the fuse unit 1 will be described. FIG. 20(A) shows a top view of the short-circuit element 110, and FIG. 20(B) shows a cross-sectional view of the short-circuit element 110. The short-circuit element 110 includes an insulating substrate 111, a heating element 112 provided on the insulating substrate 111, a first electrode 113 and a second electrode 114 provided adjacent to each other on the insulating substrate 111, and is provided adjacent to the first electrode 113 and electrically The third electrode 115 connected to the heating element 112 and the fuse unit 1 are arranged across the first and third electrodes 113, 115 to form a current path, and the first 1. The current path between the third electrodes 113, 115, and the first and second electrodes 113, 114 are short-circuited through the molten conductor. In addition, in the short-circuit element 110, a cover member 116 for protecting the inside is mounted on the insulating substrate 111.

The insulating substrate 111 is formed into a square shape using insulating members such as alumina, glass ceramics, mullite, and zirconia. In addition, as the insulating substrate 111, a material such as a glass epoxy substrate, a phenol substrate, or the like for printed wiring boards may be used.

The heating element 112 is covered with an insulating member 118 on the insulating substrate 111. In addition, the first to third electrodes 113 to 115 are formed on the insulating member 118. The insulating member 118 is provided to transmit the heat of the heating element 112 to the first to third electrodes 113 to 115 with good efficiency, and is composed of, for example, a glass layer. The heating element 112 can easily agglomerate the molten conductor by heating the first to third electrodes 113 to 115.

The first to third electrodes 113 to 115 are formed by conductive patterns such as Ag or Cu wiring. The first electrode 113 is formed adjacent to the second electrode 114 on one side and is insulated. Yudi The third electrode 115 is formed on the other side of the one electrode 113. The first electrode 113 and the third electrode 115 are electrically connected by connecting the fuse unit 1 to constitute a current path of the short-circuit element 110. In addition, the first electrode 113 is connected to the first external connection electrode 113a provided on the back surface 111b of the insulating substrate 111 via a castle-shaped contact facing the side surface of the insulating substrate 111. In addition, the second electrode 114 is connected to the second external connection electrode 114a provided on the back surface 111b of the insulating substrate 111 via a castellated contact facing the side surface of the insulating substrate 111.

The third electrode 115 is connected to the heating element 112 via the insulating substrate 111 or the heating element extraction electrode 120 provided on the insulating member 118. The heating element 112 is connected to the heating element power supply electrode 121a provided on the back surface 111b of the insulating substrate 111 via the heating element electrode 121 and the castle-shaped contact facing the side edge of the insulating substrate 111.

The first and third electrodes 113 and 115 are connected to the fuse unit 1 through a connection material 117 such as solder. As described above, since the fuse unit 1 is provided with the high-melting-point metal layer 2, the resistance to high-temperature environments is improved, so it has excellent structural properties and can be mounted between the first and third electrodes 113 and 115 through the connection material 117 , Easy connection by reflow soldering, etc. In addition, the fuse unit 1 may also use the first low-melting-point metal layer 3 or the second low-melting-point metal layer 4 provided in the lowermost layer as a connecting material to connect between the first and third electrodes 113,115.

[Flux sheet]

In addition, in the short-circuit element 110, in order to prevent the oxidation of the high-melting-point metal layer 2 or the first and second low-melting-point metal layers 3, 4 and to remove the oxide at the time of fusing and improve the fluidity of the solder, the fuse unit 1 Flux is applied on the surface or back surface. Furthermore, as shown in FIG. 20, the flux sheet 122 may be arranged on the entirety of the outermost layer on the fuse unit 1. The flux sheet 122 is formed by impregnating and holding the flux of the fluid or semi-fluid in a sheet-like support, similar to the flux sheet 87 described above, for example If the flux is impregnated with non-woven fabric or mesh fabric.

The flux sheet 122 preferably has a larger area than the surface area of the fuse unit 1. As a result, the fuse unit 1 is completely covered by the flux sheet 122, and even when the volume expands due to melting, it is possible to surely realize the rapid fusing achieved by removing oxides by the flux and improving wettability.

By arranging the flux sheet 122, the flux can also be kept in the entirety of the fuse unit 1 during the heat treatment step when the fuse unit 1 is assembled or when the short-circuit element 110 is assembled, in actual use of the short-circuit element 110 Can improve the wettability of the first and second low-melting-point metal layers 3, 4 (such as solder), and remove the oxides during the dissolution of the first and second low-melting-point metals, using the high melting point metal (such as Ag) The erosion effect improves the fast fusing.

Moreover, by arranging the flux sheet 122, even if an oxidation preventing film such as lead-free solder mainly composed of Sn is formed on the surface of the outermost refractory metal layer 2, the oxide of the oxidation preventing film can be removed, which is effective To prevent the oxidation of the high-melting-point metal layer 2 and maintain and improve the fast fusing.

In addition, the short-circuit element 110 can also replace the flux sheet 122. As shown in FIG. 21, after applying the flux 119a to the outermost layer of the fuse unit 1, a non-woven fabric or a mesh-like cloth is arranged on the flux 119a, and The flux 119a is impregnated. In addition, as shown in FIG. 22, the short-circuit element 110 may replace the flux sheet and apply the flux 119b mixed with the fibrous material to the entire outermost layer of the fuse unit 1. The flux 119b can improve the viscosity by mixing with fibrous materials, and it is not easy to flow in a high-temperature environment. The fuse unit 1 can comprehensively seek to remove oxides and improve wettability during fusing. In addition, as the fibrous material mixed with the flux 119b, for example, nonwoven fabric fibers, glass fibers, and other fibers having insulation and heat resistance can be suitably used.

In addition, in the short-circuit element 110, it is preferable that the first electrode 113 has a Very large area of 115. Thereby, the short-circuit element 110 can cause more molten conductors to condense on the first and second electrodes 113 and 114, and reliably short-circuit the first and second electrodes 113 and 114 (see FIG. 24).

In addition, although the first to third electrodes 113, 114, 115 can be formed using general electrode materials such as Cu or Ag, it is preferably formed at least on the surfaces of the first and second electrodes 113, 114 by a well-known plating process by Ni/Au plating , Ni/Pd plating, Ni/Pd/Au plating and other coatings 129. Thereby, the oxidation of the first and second electrodes 113, 114 can be prevented, and the molten conductor can be reliably maintained. In addition, when the short-circuit element 110 is reflowed, the first or second low-melting-point metal layers 3 and 4 forming the outer layer of the fuse unit 1 can be prevented from melting by connecting the solder of the fuse unit 1 or the outer layer of the fuse unit 1. The electrode 113 is eroded (solder erosion).

In addition, the first to third electrodes 113 to 115 are formed with an outflow preventing portion 126 made of an insulating material such as glass that prevents the molten conductor of the fuse unit 1 or the connection material 117 of the fuse unit 1 from flowing out.

[Cover member]

In addition, the short-circuit element 110 is provided with a cover member 116 on the surface 111a of the insulating substrate 111 provided with the fuse unit 1 to protect the inside and prevent the molten fuse unit 1 from scattering. The covering member 116 can be formed by insulating members such as various engineering plastics and ceramics. In the short-circuit element 110, since the fuse unit 1 is covered by the covering member 116, the molten metal is caught by the covering member 116 and can be prevented from flying around.

In addition, the covering member 116 has a protrusion 116b extending from the top surface 116a toward the insulating substrate 111 to at least the side surface of the flux sheet 122. The covering member 116 restricts the movement of the side surface of the flux sheet 122 by the protrusion 116b, so that the position of the flux sheet 122 can be prevented from shifting. That is, the protrusion 116b is compared to the size of the flux sheet 122 to maintain both The size of the gap is set corresponding to the position where the flux sheet 122 should be kept. In addition, the protruding portion 116b may be formed as a wall surface that is wound around the side surface of the flux sheet 122 and covered, or may be a partial protrusion.

In addition, the covering member 116 is constituted by a predetermined interval between the flux sheet 122 and the top surface 116a. The reason for this configuration is that when the fuse unit 1 is melted, it is necessary to have a gap where the melted fuse unit 1 presses the flux sheet 122 upward.

Therefore, in the covering member 116, the height of the inner space of the covering member 116 (the height up to the top surface 116a) is configured to be higher than the height of the molten fuse unit 1 on the surface 111a of the insulating substrate 111 and the flux sheet The sum of the thickness of 122 is still large.

[Short circuit of element]

The short-circuit element 110 as described above has a circuit configuration as shown in FIGS. 23(A)(B). That is, the short-circuit element 110 constituting the first electrode 113 and the second electrode 114 is normally insulated (FIG. 23(A)), and when the fuse unit 1 is melted by the heat of the heating element 112, it passes through The switch 123 where the molten conductor is short-circuited (FIG. 23(B)). In addition, the first external connection electrode 113 a and the second external connection electrode 114 a constitute both terminals of the switch 123. In addition, the fuse unit 1 is connected to the heating element 112 through the third electrode 115 and the heating element extraction electrode 120.

Also, the short-circuit element 110 is assembled in an electronic device, etc., and the two terminals 113a, 114a of the switch 123 are connected to the current path of the electronic device, and when the current path is turned on, the switch 123 is short-circuited to form a current of the electronic component path.

For example, in the short-circuit element 110, the electronic component provided on the current path of the electronic component is connected in parallel with the two terminals 113a, 114a of the switch 123. If the parallel electronic component is abnormal, the power supply electrode 121a is connected to the first external Electricity is supplied between the electrodes 113a, and the heating element 112 is energized to generate heat. After the fuse unit 1 is melted by this heat, the molten conductor is as shown in FIG. 24 As shown, it aggregates on the first and second electrodes 113,114. Since the first and second electrodes 113, 114 are formed adjacent to each other, the molten conductors aggregated on the first and second electrodes 113, 114 are combined, thereby short-circuiting the first and second electrodes 113, 114. That is, in the short-circuit element 110, the two terminals of the switch 123 are short-circuited (FIG. 23(B)), forming a bypass current path that bypasses the electronic component that has generated an abnormality. In addition, since the first and third electrodes 113 and 115 are fused by the fuse unit 1 being fused, the power supply to the heating element 112 is also stopped.

At this time, the fuse unit 1 has the first low melting point metal layer 3 having a melting point lower than the high melting point metal layer 2 and the second low melting point metal layer 4 having a melting point lower than the first low melting point metal layer 3 as described above. Therefore, the melting point of the second low-melting-point metal layer 4 starts to melt, and the high-melting-point metal layer 2 begins to erode. Therefore, the fuse unit 1 can use the erosion of the first and second low-melting-point metal layers 3 and 4 to the high-melting-point metal layer 2, the high-melting-point metal layer 2 is melted at a temperature lower than the melting temperature, and quickly Fuse.

[Modification of short-circuit element]

In addition, the short-circuit element 110 does not necessarily need to cover the heating element 112 with the insulating member 118, and the heating element 112 may be disposed inside the insulating substrate 111. By using an object having excellent thermal conductivity as the material of the insulating substrate 111, the heating element 112 can be heated in the same way as when passing through the insulating member 118 such as a glass layer.

In addition, in the short-circuit element 110, in addition to forming the heating element 112 on the insulating substrate 111 on the surface of the first to third electrodes 113 to 115 as described above, the heating element 112 may be provided on the insulating substrate 111 and the first ~The third electrode 113~115 is formed on the opposite surface. By forming the heating element 112 on the back surface 111b of the insulating substrate 111, it can be formed in a simpler process than in the insulating substrate 111. In addition, in this case, if an insulating structure is formed on the heating element 112 The component 118 is preferable in terms of protection of the resistor or insulation during assembly.

In addition, in the short-circuit element 110, the heating element 112 may be provided on the formation surface of the first to third electrodes 113 to 115 of the insulating substrate 111, and be provided in parallel with the first to third electrodes 113 to 115. By forming the heating element 112 on the surface of the insulating substrate 111, it can be formed in a simpler process than in the insulating substrate 111. In addition, in this case as well, it is preferable to form the insulating member 118 on the heating element 112.

[Fourth electrode, second fuse unit]

In addition, the short-circuit element of the present invention may be formed as shown in FIGS. 25(A) and (B) to form the fourth electrode 124 and the second and fourth electrodes 114 and 124 which are adjacent to the second electrode 114 and are mounted therebetween. 2fused fuse unit 125. The second fuse unit 125 has the same configuration as the fuse unit 1.

In addition, the short-circuit element 110 may be mounted on the fuse unit 1 and the second fuse unit 125 as shown in FIG. 25(B), or may be mounted separately as shown in FIG. 25(C). For the fuse unit 1 and the second fuse unit 125. Alternatively, as shown in FIG. 25(D), after applying the flux 119a to each of the fuse unit 1 and the second fuse unit 125 as shown in FIG. 25(D), the non-woven fabric or mesh-like fabric is loaded across the fuse On the unit 1 and the second fuse unit 125, as shown in FIG. 25(E), non-woven fabric or mesh-like fabric may be mounted on the fuse unit 1 and the second fuse unit 125, respectively. Furthermore, as shown in FIG. 25(F), the short-circuit element 110 may be coated with a flux 119b in which the fibrous material is mixed and the viscosity of the fuse unit 1 and the second fuse unit 125 is improved.

In this short-circuit element 110, the fuse unit 1 and the second fuse unit 125 melt, and the molten conductor wets and diffuses between the first and second electrodes 113, 114 to short-circuit the first and second electrodes 113, 114. The short-circuit element 110 shown in FIG. 25 is the same as the above structure except that the fourth electrode 124 and the second fuse unit 125 are provided, so the same reference numerals are given and omitted. Detailed description.

Similarly in the short-circuit element 110 shown in FIG. 25, the first and second electrodes 113 and 114 preferably have a larger area than the third and fourth electrodes 115 and 124. Thereby, the short-circuit element 110 can cause more molten conductors to condense on the first and second electrodes 113, 114, and can surely short-circuit the first and second electrodes 113, 114.

[Switching element]

Next, the switching element using the fuse unit 1 will be described. The top view of the switching element 130 is shown in FIG. 26(A), and the cross-sectional view of the switching element 130 is shown in FIG. 26(B). The switching element 130 includes an insulating substrate 131, a first heating element 132 and a second heating element 133 provided on the insulating substrate 131, a first electrode 134 and a second electrode 135 provided adjacent to each other on the insulating substrate 131, and a first electrode 134 is arranged adjacent to and electrically connected to the third electrode 136 of the first heating element 132, adjacent to the second electrode 135 and electrically connected to the fourth electrode 137 of the second heating element 133, and the fourth electrode 137 The fifth electrode 138 adjacent to the first electrode 134, 136 is provided between the first and third electrodes to form a current path, and the first and third electrodes 134, 136 are fused by heating from the first heating element 132. The fuse unit 1A and the second electrode 135 are installed across the fourth electrode 137 to the fifth electrode 138, and the current path between the second, fourth, and fifth electrodes 135, 137, and 138 is fused by heating from the second heating element 133. The second fuse unit 1B. Next, the switching element 130 is mounted on the insulating substrate 131 with a cover member 139 protecting the inside.

The insulating substrate 131 is formed into a square shape using insulating members such as alumina, glass ceramics, mullite, and zirconia. In addition, as the insulating substrate 131, a material such as a glass epoxy substrate, a phenol substrate, or the like for printed wiring boards may be used.

The first and second heating elements 132, 133 are similar to the heating element 93 described above, and have A conductive member that generates heat when energized can be formed in the same manner as the heating element 93. In addition, the first and second fuse units 1A and 1B have the same configuration as the fuse unit 1 described above.

In addition, the first and second heating elements 132 and 133 are covered on the insulating substrate 131 and covered with the insulating member 140. The first and third electrodes 134, 136 are formed on the insulating member 140 covering the first heating element 132, and the second, fourth, and fifth electrodes 135, 137, 138 are formed on the insulating member 140 covering the second heating element 133. The first electrode 134 is formed adjacent to the second electrode 135 on one side and is insulated. A third electrode 136 is formed on the other side of the first electrode 134. The first electrode 134 and the third electrode 135 are electrically connected by connecting the first fuse unit 1A, and constitute a current path of the switching element 130. In addition, the first electrode 134 is connected to the first external connection electrode 134a provided on the back surface 131b of the insulating substrate 131 via a castle-shaped contact facing the side surface of the insulating substrate 131.

The third electrode 136 is connected to the first heating element 132 via the insulating substrate 131 or the first heating element extraction electrode 141 provided on the insulating member 140. In addition, the first heating element 132 is connected to the first heating element feeding electrode 142a provided on the back surface 131b of the insulating substrate 131 via the first heating element electrode 142 and the castle-shaped contact facing the side edge of the insulating substrate 131.

A fourth electrode 137 is formed on the other side of the second electrode 135 opposite to the side adjacent to the first electrode 134. In addition, a fifth electrode 138 is formed on the other side of the fourth electrode 137 opposite to the side adjacent to the second electrode 135. The second electrode 135, the fourth electrode 137, and the fifth electrode 138 are connected to the second fuse unit 1B. In addition, the second electrode 135 is connected to the second external connection electrode 135a provided on the back surface 131b of the insulating substrate 131 via a castle-shaped contact facing the side of the insulating substrate 131.

The fourth electrode 137 is connected to the second heating element 133 via the insulating substrate 131 or the second heating element extraction electrode 143 provided on the insulating member 140. In addition, the second heating element 133 The second heating element power supply electrode 144a provided on the back surface 131b of the insulating substrate 131 is connected to the second heating element electrode 144 and the castellated contact facing the side edge of the insulating substrate 131.

Furthermore, the fifth electrode 138 is connected to the fifth external connection electrode 138a provided on the back surface of the insulating substrate 131 via a castle-shaped contact facing the side of the insulating substrate 131.

In the switching element 130, the first fuse unit 1A is connected from the first electrode 134 to the third electrode 136, and the second fuse unit 1B is connected from the second electrode 135 to the fifth electrode 138 via the fourth electrode 137. The first and second fuse units 1A, 1B are similar to the above-mentioned fuse unit 1 because the high-melting-point metal layer 2 improves the resistance to high-temperature environments, so the structure is excellent and can pass through solder etc. After the connection material 145 is mounted on the first to fifth electrodes 134 to 138, it is easily connected by reflow soldering or the like. In addition, the fuse units 1A, 1B can also use the first low-melting-point metal layer 3 or the second low-melting-point metal layer 4 provided in the lowermost layer as a connecting material to connect to the first to fifth electrodes 134 to 138 .

[Flux sheet]

In addition, in the switching element 130, in order to prevent the oxidation of the high-melting-point metal layer 2 or the first and second low-melting-point metal layers 3, 4 and to remove the oxide at the time of fusing and improve the fluidity of the solder, the fuse unit 1 Flux is applied on the surface or back surface. Furthermore, as shown in FIG. 26, the flux sheet 146 may be arranged on the entirety of the outermost layer on the fuse units 1A, 1B. The flux sheet 146 is the same as the flux sheet 87 described above, in which the flux of the fluid or semi-fluid is impregnated and held in a sheet-like support, for example, the flux is impregnated into a non-woven fabric or a mesh-like fabric Successor.

The flux sheet 146 preferably has an area larger than that of the fuse units 1A and 1B. Thereby, the fuse units 1A, 1B are completely covered by the flux sheet 146, and even when the volume is expanded due to melting, the speed of removing oxides by the flux and improving wettability can be reliably achieved Fuse.

By arranging the flux sheet 146, the flux can also be kept in the entirety of the fuse units 1A, 1B during the heat treatment step when the fuse unit 1 is assembled or when the switching element 130 is assembled. In actual use, the wettability of the first and second low-melting-point metal layers 3, 4 (such as solder) can be improved, and the oxides during the dissolution of the first and second low-melting-point metals can be removed. ) The erosive effect improves the fast fusing.

Moreover, by arranging the flux sheet 146, even if an oxidation preventing film such as lead-free solder mainly composed of Sn is formed on the surface of the outermost refractory metal layer 2, the oxide of the oxidation preventing film can be removed, which is effective To prevent the oxidation of the high-melting-point metal layer 2 and maintain and improve the fast fusing.

In addition, the switching element 130 can also replace the flux sheet 146. As shown in FIG. 27, after applying the flux 148a to the outermost layer of the fuse units 1A, 1B, a non-woven fabric or mesh-like fabric is arranged on the flux 148a. And the flux 148a is impregnated. Moreover, as shown in FIG. 28, the switching element 130 may replace the flux sheet and apply the flux 148b mixed with the fibrous material to the entire outermost layer of the fuse units 1A, 1B. The flux 148b can improve the viscosity by mixing with fibrous materials, and it is not easy to flow in a high-temperature environment. It can fully remove oxides and improve wettability in the fuse unit 1A, 1B. In addition, as the fibrous material mixed with the flux 148b, a fiber having insulation and heat resistance such as non-woven fiber and glass fiber can be very suitably used.

At this time, the switching element 130 may straddle the flux sheet 146 on the fuse unit 1A and the fuse unit 1B, or may be mounted on the fuse unit 1A and the fuse unit 1B, respectively. Alternatively, the switching element 130 may apply the flux 148a to each of the fuse unit 1A and the fuse unit 1B, and then load the non-woven fabric or mesh-like fabric across the fuse unit 1A and the fuse unit 1B, or Non-woven fabric or mesh-like fabric can be mounted on the fuse unit 1A and the fuse unit 1B, respectively. Furthermore, the switching element 130 may also be coated with a flux 148b in which a fibrous material is mixed and has improved viscosity on each of the fuse unit 1A and the fuse unit 1B.

In addition, although the first to fifth electrodes 134, 135, 136, 137, 138 can be formed using common electrode materials such as Cu or Ag, it is preferably formed at least on the surfaces of the first and second electrodes 134, 135 by a well-known plating process by Ni/Au plating Coating 149 such as coating, Ni/Pd plating, Ni/Pd/Au plating, etc. Thereby, the oxidation of the first and second electrodes 134, 135 can be prevented, and the molten conductor can be reliably maintained. In addition, when the switching element 130 is reflowed, it is possible to prevent the first electrode and the second electrode from being melted by the solder connecting the fuse units 1A, 1B or the low-melting-point metal forming the outer layers of the fuse units 1A, 1B. 134,135 erosion (solder erosion).

In addition, the first to fifth electrodes 134 to 138 are formed with an outflow preventing portion 147 made of an insulating material such as glass that prevents the molten conductor of the fuse units 1A, 1B or the connection material 145 of the fuse units 1A, 1B from flowing out.

[Cover member]

Moreover, the switching element 130 is provided with a cover member 139 on the surface 131a of the insulating substrate 131 provided with the fuse units 1A, 1B to protect the inside and prevent the fuse units 1A, 1B from melting. The covering member 139 can be formed by insulating members such as various engineering plastics and ceramics. In the switching element 130, since the fuse units 1A and 1B are covered by the covering member 139, the molten metal is caught by the covering member 139 and can be prevented from flying around.

In addition, the covering member 139 has a protrusion 139b extending from the top surface 139a toward the insulating substrate 131 to at least the side surface of the flux sheet 146. Since the covering member 139 restricts the movement of the side surface of the flux sheet 146 by the protrusion 139b, the flux sheet 146 can be prevented The position is offset. That is, the protruding portion 139b is compared with the size of the flux piece 146 to maintain the size of the predetermined gap, and is provided corresponding to the position where the flux piece 146 should be maintained. In addition, the protruding portion 139b may be formed as a wall surface that is wound around the side surface of the flux sheet 146 and covered, or may be a partially protruding portion.

In addition, the covering member 139 is constituted by a predetermined interval between the flux sheet 146 and the top surface 139a. The reason for this configuration is that when the fuse units 1A and 1B are melted, there must be a gap where the melted fuse units 1A and 1B press the flux sheet 146 upward.

Therefore, in the covering member 139, the height of the inner space of the covering member 139 (the height up to the top surface 139a) is configured to be higher than the height of the melted fuse units 1A, 1B on the surface 131a of the insulating substrate 131. The total thickness of the solder pieces 146 is still large.

[Switching element circuit]

The switching element 130 as described above has the circuit configuration shown in FIG. 29. That is, the switching element 130 constituting the first electrode 134 and the second electrode 135 is normally insulated, and the first and second fuse units 1A, 1B are melted by the heating of the first and second heating elements 132, 133 At this time, the switch 150 short-circuited through the molten conductor. In addition, the first external connection electrode 134 a and the second external connection electrode 135 a constitute two terminals of the switch 150.

In addition, the first fuse unit 1A is connected to the first heating element 132 via the third electrode 136 and the first heating element extraction electrode 141. The second fuse unit 1B is connected to the second heating element 133 via the fourth electrode 137 and the second heating element extraction electrode 143, and is further connected to the second heating element feeding electrode 144a via the second heating element electrode 144. That is, the second fuse unit 1B and the second electrode 135, the fourth electrode 137, and the fifth electrode 138 connected to the second fuse unit 1B are used to pass through the second fuse unit 1B before the operation of the switching element 130 The second electrode 135 and the fifth electrode 138 are electrically connected, and the second electrode 135 and the fifth electrode are blocked by blowing the second fuse unit 1B The protection element between 138 functions.

Next, after the switching element 130 energizes the second heating element 133 from the second heating element feeding electrode 144a, that is, as shown in FIG. 30, the second fuse unit 1B is melted by the heat of the second heating element 133, and Aggregated at the second, fourth, and fifth electrodes 135, 137, and 138, respectively. As a result, the current path across the second electrode 135 and the fifth electrode 138 connected via the second fuse unit 1B is blocked. In addition, after the switching element 130 energizes the first heating element 132 from the first heating element feeding electrode 142a, that is, the first fuse unit 1A is melted by the heat of the first heating element 132 and condenses on the first, The third electrode 134,136. As a result, as shown in FIGS. 31(A) and (B), the switching element 130 is combined with the melted conductors of the first and second fuse units 1A, 1B aggregated in the first electrode 134 and the second electrode 135, so that The first electrode 134 and the second electrode 135 in the insulation are short-circuited. That is, the switching element 130 short-circuits the switch 150, and can switch the current path across the second and fifth electrodes 135, 138 to the current path across the first and second electrodes 134, 135 (FIG. 32).

At this time, the fuse units 1A, 1B have the first low melting point metal layer 3 having a melting point lower than the high melting point metal layer 2 and the second low melting point metal layer having a melting point lower than the first low melting point metal layer 3 as described above. 4. Therefore, the melting point of the second low-melting-point metal layer 4 begins to melt, and the high-melting-point metal layer 2 begins to erode. Therefore, the fuse units 1A, 1B can be fused by the first and second low-melting-point metal layers 3, 4 to the high-melting-point metal layer 2, and the high-melting-point metal layer 2 is melted at a temperature lower than the melting temperature , Quickly blown.

In addition, the energization of the first heating element 132 is interrupted by fusing the first fuse unit 1A to block the first and third electrodes 134, 136, and the energization of the second heating element 133 is determined by the second The fuse unit 1B is fused to shut off the second and fourth electrodes 135,137 and the fourth and fifth electrodes 137,138, and is stopped.

[The first fuse unit melts first]

Here, it is preferable that the switching element 130 melts before the second fuse unit 1B before the first fuse unit 1A. In the switching element 130, since the first heating body 132 and the second heating body 133 generate heat separately, the second heating body 133 heats first as the timing of energization, and then the first heating body 132 heats up, as shown in FIG. 30 As shown, the second fuse unit 1B is melted before the first fuse unit 1A, and as shown in FIG. 31, the first and second fuse units 1A can be reliably made on the first and second electrodes 134, 135, The molten conductor of 1B aggregates and bonds, and short-circuits the first and second electrodes 134 and 135.

In addition, the switching element 130 may be formed such that the second fuse unit 1B is narrower than the first fuse unit 1A, so that the second fuse unit 1B is blown before the first fuse unit 1A. By forming the second fuse unit 1B to have a narrow width, since the fusing time can be shortened, the second fuse unit 1B can be melted before the first fuse unit 1A.

[Electrode area]

Furthermore, it is preferable that the switching element 130 has a larger area of the first electrode 134 than the third electrode 136 and a larger area of the second electrode 135 than the fourth and fifth electrodes 137 and 138. Since the retention amount of the molten conductor increases in proportion to the electrode area, the area of the first and second electrodes 134, 135 can be formed to be larger than that of the third, fourth, and fifth electrodes 136, 137, 138. The molten conductor aggregates on the first and second electrodes 134, 135, and can surely short-circuit the first and second electrodes 134, 135.

[Modification of switching element]

In addition, the switching element 130 does not necessarily need to cover the first and second heating elements 132, 133 with the insulating member 140, and the first and second heating elements 132, 133 may also be provided inside the insulating substrate 131. By using an object with excellent thermal conductivity as the material of the insulating substrate 131, the first and second heating elements 132, 133 It can be heated in the same way as when passing through an insulating member 140 such as a glass layer.

Furthermore, in the switching element 130, the first and second heating elements 132, 133 may be provided on the back surface of the insulating substrate 131 opposite to the formation surface of the first to fifth electrodes 134, 135, 136, 137, 138. By forming the first and second heating elements 132 and 133 on the back surface 131b of the insulating substrate 131, it can be formed in a simpler process than in the insulating substrate 131. In addition, in this case, if the insulating member 140 is formed on the first and second heating elements 132 and 133, it is preferable in terms of protection of the resistor or ensuring insulation during assembly.

In addition, the switching element 130 may be provided with the first and second heating elements 132, 133 on the formation surface of the first to fifth electrodes 134, 135, 136, 137, 138 of the insulating substrate 131, and juxtaposed with the first to fifth electrodes 134 to 138. By forming the first and second heating elements 132 and 133 on the surface 131a of the insulating substrate 131, it can be formed in a simpler process than in the insulating substrate 131. In this case as well, it is preferable to form the insulating member 140 on the first and second heating elements 132 and 133.

1‧‧‧Fuse unit

2‧‧‧High melting point metal layer

3‧‧‧First low melting point metal layer

4‧‧‧The second low melting point metal layer

Claims (29)

A fuse unit having: a high melting point metal layer; a first low melting point metal layer having a melting point lower than the above high melting point metal layer; and a second low melting point metal layer having a melting point lower than the first low melting point metal layer above The wire unit has four or more layers stacked in the order of the second low melting point metal layer, the high melting point metal layer, the first low melting point metal layer, and the high melting point metal layer. A fuse unit having: a high melting point metal layer; a first low melting point metal layer having a melting point lower than the above high melting point metal layer; and a second low melting point metal layer having a melting point lower than the first low melting point metal layer above In the wire unit, the inner layer is the first low melting point metal layer, the outer layer deposited on the inner layer is the high melting point metal layer, and the outermost layer deposited on the outer layer is the second low melting point metal layer. For example, in the fuse unit of claim 1 or 2, the volume of the first low melting point metal layer is larger than the volume of the high melting point metal layer. For example, in the fuse unit of claim 1 or 2, the volume of the second low melting point metal layer is larger than the volume of the high melting point metal layer. For example, the fuse unit according to item 1 or 2 of the patent application, wherein the high melting point metal layer is Ag, Cu or an alloy containing Ag or Cu as the main component, and the first low melting point metal layer is Sn or Sn is the main component For the alloy of the components, the second low-melting-point metal layer is Bi, In or an alloy containing Bi or In. A fuse unit having: a high melting point metal layer; a first low melting point metal layer having a melting point lower than the above high melting point metal layer; and a second low melting point metal layer having a melting point lower than the above first low melting point metal layer; the above high A melting point metal layer is deposited between the first low melting point metal layer and the second low melting point metal layer, the high melting point metal layer is Ag, Cu or an alloy containing Ag or Cu as a main component, the first low melting point The metal layer is Sn or an alloy containing Sn as a main component, the second low melting point metal layer is Bi, In or an alloy containing Bi or In, and the fuse unit is based on the first low melting point metal layer and the high The melting point metal layer, the second low melting point metal layer, and the high melting point metal layer are sequentially stacked in four or more layers. A fuse element includes: an insulating substrate; first and second electrodes formed on the insulating substrate; and a fuse unit, at least a high melting point metal layer and a first low melting point having a melting point lower than the high melting point metal layer are laminated A metal layer is bridged between the first and second electrodes; the fuse unit is connected to the first and second electrodes by a second low-melting metal layer having a melting point lower than the first low-melting metal layer . A fuse element according to claim 7 of the patent application, wherein in the fuse unit, the high-melting-point metal layer is laminated between the first low-melting-point metal layer and the second low-melting-point metal layer, at least one of the outermost layers This is the second low melting point metal layer. A protection element with: An insulating substrate; a heating element formed on or inside the insulating substrate; first and second electrodes provided on the insulating substrate; a heating element extraction electrode electrically connected to the heating element; and a fusible conductor, The second electrode is bridged from the first electrode through the heating element extraction electrode; the fusible conductor is at least composed of a fusion of a high melting point metal layer and a first low melting point metal layer having a melting point lower than the high melting point metal layer Wire unit; the fuse unit is connected to the first and second electrodes and the heating element extraction electrode by a second low melting point metal layer having a melting point lower than the first low melting point metal layer, by the heat generation The body is heated and melts, blocking the first and second electrodes. A protection element according to claim 9 of the patent application, wherein in the fuse unit, the high-melting-point metal layer is laminated between the first low-melting-point metal layer and the second low-melting-point metal layer, and the outermost layer of at least one of the layers is The above second low melting point metal layer. A short-circuit element comprising: an insulating substrate; a heating element formed on or inside the insulating substrate; first and second electrodes provided adjacent to the insulating substrate; and a third electrode provided on the insulating substrate And electrically connected to the heating element; and a fusible conductor across the first and third electrodes; the fusible conductor includes at least a laminated high-melting metal layer and a melting point lower than the high-melting metal layer. 1 Composition of low-melting metal layer fuse unit; The fuse unit is connected to the first and third electrodes by a second low-melting-point metal layer having a melting point lower than the first low-melting-point metal layer, and is melted by energization of the heating element to cause the first 1. A short circuit between the second electrodes interrupts the first and third electrodes. A short-circuit element according to claim 11 of the patent application, wherein, in the fuse unit, the high-melting-point metal layer is laminated between the first low-melting-point metal layer and the second low-melting-point metal layer, and the outermost layer of at least one of them is The above second low melting point metal layer. A short-circuit element comprising: an insulating substrate; a heating element formed on or inside the insulating substrate; first and second electrodes provided adjacent to the insulating substrate; and a third electrode provided on the insulating substrate And electrically connected to the heating element; and a fusible conductor across the first and third electrodes; the fusible conductor includes at least a laminated high-melting metal layer and a melting point lower than the high-melting metal layer. 2 The fuse unit of the low melting point metal layer; the above fuse unit is connected to the first low melting point metal layer by a melting point lower than the high melting point metal layer and a melting point higher than the second low melting point metal layer 1. The third electrode is melted by the energization and heating of the heating element to short-circuit the first and second electrodes and block the first and third electrodes. A short-circuit element according to claim 13 of the patent application, wherein in the fuse unit, the high-melting-point metal layer is laminated between the first low-melting-point metal layer and the second low-melting-point metal layer, and the outermost layer of at least one of the layers is The first low melting point metal layer. A switching element with: An insulating substrate; the first and second heating elements are formed on or inside the insulating substrate; the first and second electrodes are provided adjacent to the insulating substrate; the third electrode is provided on the insulating substrate and It is electrically connected to the first heating element; the first fusible conductor is connected across the first and third electrodes; the fourth electrode is provided on the insulating substrate and is electrically connected to the second heating element; 5 electrodes, provided on the insulating substrate adjacent to the fourth electrode; and a second fusible conductor, spanning from the second electrode to the fifth electrode via the fourth electrode; the first and second fusible The conductor is composed of a fuse unit in which three or more metal layers having different melting points are laminated; the second fusible conductor is melted by the energization of the second heating element to block the gap between the second and fifth electrodes ; The first fusible conductor is melted by the energization of the first heating element to short-circuit the first and second electrodes. A switching element comprising: an insulating substrate; first and second heating elements formed on or inside the insulating substrate; first and second electrodes provided adjacent to the insulating substrate; and a third electrode provided On the insulating substrate and electrically connected to the first heating element; the first fusible conductor is connected across the first and third electrodes; the fourth electrode is provided on the insulating substrate and generates heat with the second Body electrical connection; the fifth electrode is provided adjacent to the fourth electrode on the insulating substrate; and The second fusible conductor is bridged from the second electrode to the fifth electrode via the fourth electrode; the first and second fusible conductors are at least composed of a laminated high melting point metal layer and a melting point lower than the high melting point metal The fuse unit of the first low-melting-point metal layer of the layer; the first fusible conductor is connected to the first and third by the second low-melting-point metal layer having a melting point lower than the first low-melting-point metal layer Electrode; the second fusible conductor is connected to the second, fourth, and fifth electrodes by a second low-melting metal layer having a melting point lower than the first low-melting metal layer; by the second heating element The energized heating causes the second fusible conductor to melt, blocking the second and fifth electrodes; the energized heating of the first heating body melts the first fusible conductor to melt the first and second electrodes Short circuit. A switching element according to claim 16 of the patent application, wherein in the first and second fusible conductors, the high-melting-point metal laminate layer is between the first low-melting-point metal layer and the second low-melting-point metal layer, at least One outermost layer is the above-mentioned second low melting point metal layer. A switching element comprising: an insulating substrate; first and second heating elements formed on or inside the insulating substrate; first and second electrodes provided adjacent to the insulating substrate; and a third electrode provided On the insulating substrate and electrically connected to the first heating element; the first fusible conductor is connected across the first and third electrodes; the fourth electrode is provided on the insulating substrate and generates heat with the second Body electrical connection; the fifth electrode is provided adjacent to the fourth electrode on the insulating substrate; and The second fusible conductor is bridged from the second electrode to the fifth electrode via the fourth electrode; the first and second fusible conductors are at least composed of a laminated high melting point metal layer and a melting point lower than the high melting point metal The fuse unit of the second low melting point metal layer of the layer; the first fusible conductor is formed by the first low melting point metal layer having a melting point lower than the high melting point metal layer and higher than the second low melting point metal layer Connected to the first and third electrodes; the second fusible conductor is connected to the first low-melting metal layer having a melting point lower than the high-melting metal layer and a melting point higher than the second low-melting metal layer. The second, fourth, and fifth electrodes; the second fusible conductor is melted by the energization of the second heating element to interrupt the second and fifth electrodes; the energization of the first heating element Heat generation melts the first soluble conductor and short-circuits the first and second electrodes. According to the switching element of claim 18, in the first and second fusible conductors, the high-melting-point metal layer is laminated between the first low-melting-point metal layer and the second low-melting-point metal layer, at least One of the outermost layers is the above-mentioned first low melting point metal layer. A fuse unit, characterized by comprising: a high-melting-point metal layer composed of a solid metal easily soluble in metal; a first low-melting-point metal layer composed of a metal soluble in at least one side of the high-melting metal layer ; And the second low-melting-point metal layer, which is further soluble in the other side of the high-melting-point metal layer; the high-melting-point metal layer is made of Ag, Cu or an alloy with Ag or Cu as the main component The first low melting point metal layer has a second melting temperature lower than the high melting point metal layer, and the second low melting point The spot metal layer melts at the above-mentioned construction working temperature and has a third melting temperature below the second melting temperature. For example, in the fuse unit of claim 20, in the first low melting point metal layer, Sn or an alloy containing Sn as a main component is used. For example, in the fuse unit of claim 20, in the second low melting point metal layer, Bi, In, or an alloy containing Bi or In is used. As for the fuse unit of claim 21, wherein the second low melting point metal layer uses Bi, In, or an alloy containing Bi or In. As for the fuse unit according to any one of patent application items 20 to 23, wherein the above-mentioned assembly operation temperature is the surface assembly temperature of reflow. A fuse element, comprising: an insulating substrate; first and second electrodes formed on the insulating substrate; a fuse unit spanning between the first and second electrodes; and a covering member covering the above A fuse unit, the fuse unit includes: a high melting point metal layer composed of a solid metal that is easily soluble in the metal; a first low melting point metal layer composed of a metal that is soluble on at least one side of the high melting point metal layer; And a second low-melting-point metal layer composed of a soluble metal that is further soluble in the other side of the high-melting-point metal layer; the high-melting-point metal layer is composed of Ag, Cu, or an alloy containing Ag or Cu as a main component , Having a first melting temperature that exceeds the assembly operating temperature, the first low melting point metal layer has a second melting temperature lower than the high melting point metal layer, The second low-melting-point metal layer melts at the construction work temperature and has a third melting temperature below the second melting temperature. A protection element, comprising: an insulating substrate; a heating element formed on the insulating substrate or inside the insulating substrate; first and second electrodes provided on the insulating substrate; a heating element extraction electrode, which generates heat Body electrical connection; and a fuse unit, which is bridged from the first electrode to the second electrode via the heating element extraction electrode, and the fuse unit is melted by the energization of the heating body to block the first 1. Between the second electrodes, the fuse unit includes: a high melting point metal layer composed of a solid metal that is easily soluble in the metal; a first low melting point metal layer composed of a metal that is soluble on at least one side of the high melting point metal layer And the second low-melting-point metal layer is composed of a soluble metal that is further soluble in the other side of the high-melting-point metal layer; the high-melting-point metal layer is composed of Ag, Cu or Ag or Cu as the main component The alloy is composed of a first melting temperature that exceeds the assembly operating temperature, the first low melting point metal layer has a second melting temperature lower than the high melting point metal layer, and the second low melting point metal layer is in the assembly The operating temperature melts and has a third melting temperature below the second melting temperature. A short-circuit component characterized by: An insulating substrate; a heating element formed on or inside the insulating substrate; first and second electrodes provided adjacent to the insulating substrate; and a third electrode provided on the insulating substrate and electrically connected to the heating element Sexual connection; and a fuse unit, which is connected between the first and third electrodes; the fuse unit is melted by the energization of the heating element to short-circuit the first and second electrodes and shield Between the first and third electrodes, the fuse unit includes: a high melting point metal layer composed of a solid metal that is easily soluble in metal; and a first low melting point metal layer composed of at least one side of the high melting point metal layer Soluble metal; and the second low melting point metal layer, which is further soluble in the other side of the high melting point metal layer; the high melting point metal layer is made of Ag, Cu or Ag or Cu as The main component alloy is composed of a first melting temperature that exceeds the assembly operation temperature. The first low melting point metal layer has a second melting temperature lower than that of the high melting point metal layer. The second low melting point metal layer is at The above-mentioned assembly working temperature melts and has a third melting temperature below the second melting temperature. A switching element comprising: an insulating substrate; first and second heating elements formed on or inside the insulating substrate; first and second electrodes provided adjacent to the insulating substrate; and a third electrode provided On the insulating substrate and electrically connected to the first heating element; a first fuse unit is connected across the first and third electrodes; a fourth electrode is provided on the insulating substrate and generates heat with the second Body electrical connection; A fifth electrode is provided adjacent to the fourth electrode on the insulating substrate; and a second fuse unit is bridged from the second electrode to the fifth electrode via the fourth electrode, and the first and second fuses The wire unit includes: a high-melting-point metal layer composed of a solid metal that is easily soluble in the metal; a first low-melting-point metal layer composed of a metal soluble in at least one side of the high-melting-point metal layer; and a second low-melting-point metal The layer is composed of a soluble metal that is further soluble in the other side of the high-melting-point metal layer; the high-melting-point metal layer is composed of Ag, Cu, or an alloy containing Ag or Cu as the main component, and has over-construction work The first melting temperature of the temperature, the first low-melting-point metal layer has a second melting temperature lower than the high-melting-point metal layer, the second low-melting metal layer melts at the assembly working temperature, and has the second At the third melting temperature below the melting temperature, the second fuse unit is melted by the energized heating of the second heating element to block the second and fifth electrodes, and the energized heating of the first heating element causes the The first fuse unit melts and short-circuits the first and second electrodes. A fuse unit having: a high melting point metal layer; a first low melting point metal layer having a melting point lower than the above high melting point metal layer; and a second low melting point metal layer having a melting point lower than the above first low melting point metal layer; the above high A melting point metal layer is deposited between the first low melting point metal layer and the second low melting point metal layer, the high melting point metal layer is Ag, Cu or an alloy containing Ag or Cu as a main component, the first low melting point The metal layer is Sn or an alloy containing Sn as the main component, and the above-mentioned second low melting point The metal layer is Bi, In or an alloy containing Bi or In.

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