JP2000260280A - Protecting element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protecting element including a fusible alloy and a resistance to melt the alloy with heat generating caused by the carrying of the current, allowing optimum setting of the resistance and capable of melting the alloy in short time with the heat emitted by the resistance. SOLUTION: A resistance 64 is formed straddling electrodes 56 and 57 formed apart on the obverse surface of an insulated board 51 and covered with a insulator layer 65, which is irradiated with laser, and the resistance 64 is trimmed and a cut or cuts 64a/64c is formed so that the resistance is set to the optimum value, and a soluble alloy is connected fast in such a way as straddling electrodes formed on the insulator layer 65. This is further covered with flux, covered with an insulating cap, and secured sealedly with adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a protection element,
More particularly, the present invention relates to a protective element including a fusible alloy and a resistor for forcibly blowing the fusible alloy by heat generated by electric current. The present invention also relates to a method for manufacturing a protection element, and more particularly, to a method for trimming a resistance value of a resistor in a protection element including a fusible alloy and a resistor forcibly blowing the fusible alloy by energizing heat generation and It relates to the arrangement relationship between the resistor and the fusible alloy and the order of the forming steps.

[0002]

2. Description of the Related Art In recent years, protection devices have been used to protect electronic devices and household goods from fire caused by overheating of the electronic devices. As this kind of protection element, there is a thermal fuse using a fusible alloy that melts at a specific temperature.
This thermal fuse is designed to energize through a fusible alloy at a normal temperature, and open the circuit by melting the fusible alloy at an abnormal temperature. Further, in addition to the above-mentioned temperature fuse, a fusible alloy that melts at an arbitrary temperature and a resistor for heating the fusible alloy are provided, and the fusible alloy is forcibly blown off by heat generated by energizing the resistor. There is a composite type protection element that opens a circuit by opening the circuit. As such a composite type protection element, for example, Japanese Utility Model Laid-Open No. 58-5257 discloses a chip type protection element. Hereinafter, this chip-type protection element will be described with reference to the drawings.

FIG. 12 shows a plan view of a conventional protection element.
FIG. 13 shows a longitudinal sectional view of the protection element. FIG. 12 and FIG.
In 3, a rectangular insulating substrate 81 made of a heat-resistant insulating material such as alumina ceramic has three electrodes 82, 83, 84 formed by applying and baking silver paste or the like at positions separated in the longitudinal direction. The pair of electrodes 8
A resistor 85 formed by applying and baking a resistance paste is formed between the pair of electrodes 83 and 83.
Between 84, a fusible alloy 86 that melts at a specific temperature is connected and fixed.

Next, an example of a method of using the above-described protection element will be described. FIG. 12 also shows a circuit diagram illustrating an example of how to use the protection element. That is, the resistor 85 is connected to the electric circuit 87 via the electrodes 82 and 83 of the protection element.
And the fusible alloy 86 is connected to the shutoff protection circuit 88 via the electrodes 83 and 84. This shutoff protection circuit 88 has a relay 89 and its two contacts a and b, and connects the relay 89 and the fusible alloy 86 in series and connected to power terminals T1 and T2. The two contacts a,
b denotes the power terminals T1 and T2 and the electric circuit 87, respectively.
And is interposed between them.

In the above-mentioned example of use of the protection element, a current flows to the relay 89 via the fusible alloy 86 in a normal state, the contacts a and b are closed, and power is supplied to the electric circuit 87. However, when an abnormality occurs, an overcurrent flows through the electric circuit 87, and the resistor 85 generates abnormal heat. This heat is transmitted to the fusible alloy 86 via the insulating substrate 81, and the fusible alloy 86 melts. , Relay 8 of protection circuit 88
9 stops its operation and opens its contacts a and b.
The power supply to the electric circuit 87 is stopped to protect the electric circuit 87.

[0005] However, in the above protection element,
Since the resistor 85 is formed by applying and baking a resistor paste, for example, it is difficult to set the resistance to an optimum value. In addition, since the resistor 85 and the fusible alloy 86 are formed side by side on the one side of the insulating substrate, it takes a relatively long time to start melting the fusible alloy 86 after the resistor 85 is energized. There is a point.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a protective element having a fusible alloy and a resistor, which can set the resistance of the resistor to an optimum value, and can shorten the time from the start of energization to the resistor. An object of the present invention is to provide a protection element capable of reliably blowing a fusible alloy.

[0007]

According to the present invention, there is provided a protection element comprising: an insulating substrate; a resistor formed on one surface of the insulating substrate; and an insulator layer coated on the resistor. A fusible alloy formed on the other surface side of the insulating substrate, wherein the resistor is trimmed, and the fusible alloy corresponds to a position on a current path near a trimming portion of the resistor. It is characterized by being formed.
The method for manufacturing a protection element according to the present invention is a method for manufacturing a protection element having a fusible alloy on an insulating substrate and a resistor forcibly blowing the fusible alloy by energizing heat. The method is characterized by including a step of forming, a step of forming an insulator layer on the resistor, and a step of trimming the resistor by irradiating a laser from above the insulator layer.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION
An insulating substrate, a resistor formed on one surface side of the insulating substrate, and an insulator layer coated on the resistor,
A fusible alloy formed on the other surface side of the insulating substrate, wherein the resistor is trimmed, and the fusible alloy corresponds to a position on a current path near a trimming portion of the resistor. This is a protection element characterized by being formed by:

According to a second aspect of the present invention, there is provided an insulating substrate, and a resistor formed on one surface side of the insulating substrate;
An insulator layer formed on the resistor, and a fusible alloy formed on the insulator layer, the resistor is trimmed, and the fusible alloy is A protection element formed corresponding to a position on a current path near a trimming portion of a body.

The invention according to claim 3 of the present invention is the protection element according to claims 1 or 2, wherein the trimming of the resistor is performed in a direction orthogonal to the current direction.

The invention according to claim 4 of the present invention is the protection element according to claim 3, wherein the trimming of the resistor is performed at a plurality of positions of the resistor.

The invention according to claim 5 of the present invention is the protection element according to claim 4, wherein the trimming of the resistor is performed on the insulating layer.

According to a sixth aspect of the present invention, in the protection element according to the fifth aspect, the insulator layer after trimming of the resistor is further covered with an insulator layer. is there.

According to a seventh aspect of the present invention, there is provided a method for manufacturing a protective element having a fusible alloy and a resistor for forcibly blowing the fusible alloy by energizing heat generation on the insulating substrate. Forming a resistor on the resistor, forming an insulator layer on the resistor, and trimming the resistor by irradiating a laser from above the insulator layer. It is a manufacturing method of a protection element.

According to a seventh aspect of the present invention, the insulator layer after trimming the resistor is covered with an insulator layer having a lower melting point than the insulator layer.
It is a protection element described in

The invention according to claim 8 of the present invention is a method for manufacturing a protection element having a fusible alloy and a resistor for forcibly blowing the fusible alloy by energizing heat generation on an insulating substrate, the method comprising: Forming a resistor on the resistor, forming an insulator layer on the resistor, trimming the resistor by irradiating a laser from above the insulator layer, And a step of forming an insulator layer.

According to a tenth aspect of the present invention, there is provided a method for manufacturing a protective element having a fusible alloy and a resistor for forcibly blowing the fusible alloy by energizing heat generation on an insulating substrate. Forming a resistor on the resistor, forming an insulator layer on the resistor, trimming the resistor by irradiating a laser from above the insulator layer, Forming an insulator layer having a lower melting point than the above, and a step of connecting and fixing a fusible alloy at a position corresponding to a current path of the trimmed resistor. It is.

[0020]

Embodiments of the present invention will be described below. FIG. 1 is a longitudinal sectional view of a protection element A according to a first embodiment of the present invention along a central axis in the longitudinal direction. FIG. 2 shows the protection element A of FIG. FIG. 3 is a bottom view of the protection element A in FIG. Hereinafter, description will be made with reference to FIGS. First, reference numeral 1 denotes a substantially rectangular insulating substrate made of a ceramic such as alumina. As shown in FIGS. 1 and 2, for example, a silver paste or a silver paste is provided on both ends of one surface in the longitudinal direction.
Electrodes 2 and 3 formed by applying and firing a conductive material such as palladium paste, and terminal portions 4 and 5 formed by applying and firing the same conductive material as described above at both ends in the longitudinal direction of the other surface. Having. A ladder-shaped insulating frame 6 made of ceramic such as alumina is integrally formed on one surface of the insulating substrate 1 so that the inner and outer ends of the electrodes 2 and 3 are exposed. . On the other hand, it is formed by coating and baking a resistor paste in which resistor particles such as ruthenium oxide are mixed in, for example, a glass paste, over the inner ends of the terminal portions 4 and 5 on the other surface of the insulating substrate 1. It has a resistor 7. The resistor 7 is covered with an insulator layer 8 formed by applying and baking a glass paste or the like, for example. The insulator layer 8 is for preventing the resistor 7 from causing a short circuit or a withstand voltage failure with a terminal portion, a wiring layer, a mounted component, or the like in a mounting body (not shown) such as a printed circuit board. is there.

After the formation of the insulator layer 8, the resistor 7 is trimmed by irradiating a laser from above the insulator layer 8 to adjust the resistance value. 7a, 7b in FIG.
Indicates a cut formed in the resistor 7 by trimming the resistor 7. The reason why the resistor 7 is trimmed after the formation of the insulator layer 8 is as follows. That is, after the resistor 7 is formed, the resistor 7
When the trimming is performed by directly irradiating the laser with the resistor, the resistor 7 at the trimming location is melted and removed, and at the same time,
Since the resistor 7 in the portion adjacent to the trimming portion also melts and agglomerates by surface tension, it is difficult to form a sharp cut, and it is difficult to adjust the resistance value. On the other hand, the insulator layer 8 is formed on the resistor 7 so that the insulator layer 8
When the trimming is performed by irradiating a laser from above, even if the resistor 7 adjacent to the trimming portion attempts to melt, the presence of the insulating layer 8 prevents heat from being taken out, thereby preventing melting. Even if it melts, the presence of the insulator layer 8 on top of it prevents the aggregation, so that a sharp cut can be formed and the resistance value can be easily adjusted. Therefore, it is desirable to perform the trimming of the resistor after the formation of the insulator layer 8. When the resistor 7 is trimmed from above the insulator layer 8, the resistor component constituting the resistor 7 is melted and scattered, and the resistor component is formed on the insulator layer 8 near the cuts 7 a and 7 b due to the trimming. Since the insulating layer 8 may adhere, the insulating layer 8 after the trimming is performed.
It is desirable that an insulating layer made of glass, epoxy resin, or the like having a lower melting point than the insulating layer 8 is formed again on the lower surface (the lower surface in FIG. 1).

Further, as shown in FIG.
A fusible alloy 9 is connected and fixed between the inner ends of the electrodes 2 and 3 which are exposed at the window 6a of the insulating frame 6 on one side. The fusible alloy 9 is connected and fixed to a position corresponding to a current path near the cuts 7a and 7b by trimming of the resistor 7, that is, a position corresponding to a gap between the cuts 7a and 7b by trimming. Unlike the fusible alloy for the thermal fuse, the fusible alloy 9 does not melt in response to the ambient temperature, but is forcibly blown by energizing heating of the resistor 7. It can be selected from materials having a wide range of melting points, from a low melting point called solder to a high melting point called high temperature solder. The entire surface of the fusible alloy 9 is covered with the flux 10. This flux 10 always covers and protects the fusible alloy 9, and softens and melts to activate the surface of the fusible alloy 9 when the resistor 7 is energized and heated,
It is intended to melt the fusible alloy 9 at an accurate temperature and select and use one having a slightly lower softening point or melting point than the fusible alloy 9.

Terminal portions 4 and 5 on the back surface of the insulating substrate 1 have low melting point solder layers 11 and 12 for surface mounting, respectively.
Are formed. Here, these low melting point solder layers 1
The melting points of the fusible alloy 9 and the flux 1
It is formed in a height dimension lower than the melting point of 0 and the height thereof protrudes from the lower surface of the insulator layer 8 covering the resistor 7.

Plate-shaped leads 13 and 14 are connected to the outer ends of the electrodes 2 and 3 exposed from the cutouts 6b and 6c of the insulating frame 6 on one surface of the insulating substrate 1, respectively.

The upper portion of the insulating frame 6 is covered with an insulating cap 15 made of ceramic or resin such as alumina, and is further connected to the outer ends of the electrodes 2 and 3 of the leads 13 and 14. Sealing resins 16 and 17 are filled and sealed in recesses formed by the cutouts 6a and 6c of the insulating substrate 1 and the insulating frame 6 and the insulating cap 15, which are the connection portions of.

2, the central axis X in the longitudinal direction of the insulating substrate 1 at the cutting position in the longitudinal sectional view of the protection element A shown in FIG. Are also shown.

According to the protection element A having the above-described configuration, the resistance can be easily and optimally adjusted by trimming the resistor 7, so that the protection element having the resistor having a desired resistance can be used. can get. Moreover, the current flowing through the resistor 7 is reduced by the cuts 7a, 7
b, the resistor 7 has a particularly high calorific value between the cuts 7a and 7b due to the trimming. However, the fusible alloy 9 is a part of the trimming which is the largest heat generating portion of the resistor 7. Since the fusible alloy 9 is formed at the position corresponding to the gap 7a, 7b, the fusible alloy 9 can be reliably melted in a short time after the energization of the resistor 7 is started.

Next, a protection element B according to a second embodiment of the present invention will be described. FIG. 4 is a longitudinal sectional view of the protection element B, and FIG.
6 is a plan view in which the insulating material and the flux of the protection element B are removed so that the internal structure can be seen. FIG. 6 is a bottom view of the protection element B. 4 to 6, reference numeral 21 denotes a substantially rectangular insulating substrate made of ceramic such as alumina, and has arc-shaped cutouts 22, 23, 24 and 25 at four corners. A silver paste or a silver paste
A pair of electrodes 26 and 27 are formed by applying and baking a conductive material such as palladium paste. These electrodes 26,
27 is a pair of notch portions 2 located at the opposite corners, respectively.
2, 23, and further cutouts 22, 23
Is formed so as to extend to the end face.

On the back surface of the insulating substrate 21, the notch 2
Terminal portions 28, 29, 30, and 31 formed by applying and baking a conductive material such as a silver paste or a silver-palladium paste are provided in the vicinity of 2, 23, 24, and 25. The respective terminal portions 28 and 29 formed in the vicinity of the pair of diagonally located notches 22 and 23 are interposed through conductive layers formed on the end faces of the notches 22 and 23. Surface electrode 2
6, 27 are connected. Further, the terminal portions 30 and 31 formed near the other pair of notch portions 24 and 25 located at the opposite corners are separated from each other at the central portion of the back surface of the insulating substrate 21 so as to face the extending portions 30a and 31a. Having. A resistor 32 formed by applying and firing a resistor paste in which resistor particles such as ruthenium oxide are mixed in a glass paste is formed over the extending portions 30a and 31a. Further, the resistor 32 is covered with an insulator layer 33 formed by applying and firing a glass paste or the like.

The resistor 32 is trimmed by irradiating a laser from above the insulator layer 33, and cuts 3
2a and 32b. Due to this trimming, a resistance paste component constituting the resistor 32 may adhere to the insulator layer 33. Therefore, a lower layer than the insulator layer 33 is again formed on the insulator layer 33 after the trimming. It is desirable to form an insulating layer made of glass, epoxy resin, or the like having a melting point.

Returning to the front side of the insulating substrate 21 again, the fusible alloy 3 extends between the inner ends of the pair of electrodes 26 and 27.
4 is fixedly connected. And this fusible alloy 34
Is covered with the flux 35. Further, the upper part of the flux 35 is covered with a box-shaped insulating cap 36 made of a molded body such as ceramic or resin.
The adhesive 37 is fixedly sealed to the insulating substrate 21.

Returning to the back side of the insulating substrate 21, solder layers 38, 39, 40, and 41 are formed on the terminals 28, 29, 30, and 31, respectively. These solder layers 38, 39, 40 and 41 are for connecting and fixing the protection element B to the terminal portion of the mounting body such as a printed circuit board by a surface mounting method, and their respective heights are apparent from FIG. In this way, it is formed so as to be higher than the insulator layer 33 covering the resistor 32 (projected downward in FIG. 4).

According to the protection element B of the present invention described above, since the resistor 32 is trimmed similarly to the protection element A of the first embodiment, the resistance of the resistor 32 can be easily and optimally adjusted. Can be adjusted. In addition, since the leadless structure is adopted as compared with the protection element A, the lead (13, 14)
Is unnecessary, the material cost can be reduced, and a space for connecting the leads (13, 14) to the surface electrodes 26, 27 of the insulating substrate 21 becomes unnecessary, and the entire protection element B can be downsized. Furthermore, all terminal portions 28, 29, 3
There is a feature that 0 and 31 can be simultaneously assembled to a mounting body such as a printed circuit board.

FIG. 7 is a longitudinal sectional view of a protection element C according to a third embodiment of the present invention. 8 to 10 show plan views of the insulating substrate and the like in each process step of the protection element C. FIG. 11 shows a bottom view of the protection element C. Hereinafter, the protection element C will be described with reference to FIGS. In the figure, reference numeral 51 denotes a substantially rectangular insulating substrate made of alumina ceramic or the like.
At four corners, arc-shaped notches 52, 53, 54 and 55 are provided. A pair of electrodes 56 and 57 are formed by applying and baking a conductive material such as a silver paste or a silver-palladium paste at spaced positions on the surface of the insulating substrate 51. These electrodes 56 and 57 are formed so as to extend toward the notch portions 52 and 53 at the pair of diagonal positions, and are formed to extend to the end surfaces of the respective notch portions 52 and 53. I have. A pair of electrodes 58 and 59 are formed by applying and baking a conductive material such as a silver paste or a silver-palladium paste similarly in the vicinity of the notch portions 54 and 55 at the other pair of diagonal positions. These electrodes 58 and 59 are formed to extend to the end faces of the respective cutouts 54 and 55.

FIG. 11 is a bottom view of the insulating substrate 51.
Terminal portions 60, 61, 62, 63 formed by applying and baking a conductive material such as a silver paste or a silver-palladium paste near the cutouts 52, 53, 54, 55 at the four corners. The terminal portions 60, 61, 62, 63
The electrodes 56, 57, and 5 on the front side through the conductive layers formed on the end faces of the notches 52, 53, 54, and 55, respectively.
8,59. Here, each of the electrodes 56,
57, 58, 59 and terminal portions 60, 61, 62, 6
3 can be formed by coating and firing simultaneously in the process.

Returning to the front side of the insulating substrate 51 again, FIG.
As shown in FIG. 5, a resistor paste in which resistor particles such as ruthenium oxide are mixed in a glass paste is applied over the electrodes 56 and 57 to form a resistor 64 by firing.

Each of the electrodes 56 and 57 and the resistor 64
Is covered with an insulator layer 65 by applying and baking a glass paste or the like, as shown in FIG. Then, laser is irradiated from above the insulator layer 65 to trim the resistor 64. The resistor 64 in FIG. 9 shows a state after trimming, and a cut 6 from one side end of the resistor 64 in the short direction.
4a, a cut 64b from the opposite end, and a cut 64c from the one end again are formed in a staggered manner. by this,
The current flowing through the resistor 64 is meandering around the cuts 64a to 64c. It is desirable that an insulator layer is formed again on the insulator layer 65 after the trimming for the same reason as described above. The insulating layer to be formed again is desirably formed of a lower electrode, a resistor, and a glass paste having a lower melting point than the insulating layer.

FIG. 10 shows a pair of electrodes 66 and 67 formed separately on an insulator layer 65 covering the resistor 64.
FIG. 9 is a plan view showing a fusible alloy 68 formed between these electrodes 66 and 67. Here, the electrodes 66 and 67 are formed to extend toward the cutouts 54 and 55 and are connected to the electrodes 58 and 59 formed near the cutouts 54 and 55. Therefore, these electrodes 58 and 59 are connected to the terminal portions 62 and 63 on the back surface via the conductive layers formed to extend to the end surfaces of the notches 54 and 55.

Returning to FIG. 7, on the fusible alloy 68,
Coated with flux 69. This flux 69
Is covered by a box-shaped insulating cap 70 made of a molded body such as ceramic or resin, and the lower end of the periphery of the insulating cap 70 is fixedly sealed to the insulating substrate 51 by an adhesive 71.

Returning to FIG. 11, the solder layers 7 are applied to the terminal portions 60, 61, 62 and 63 on the back surface of the insulating substrate 51.
2, 73, 74, 75 are applied. This solder layer 7
Reference numerals 2, 73, 74, and 75 are for connecting and fixing the protection element C to a terminal portion of an attachment (not shown) such as a printed circuit board by a surface mounting method.

According to the protection element C of the above embodiment, the cuts 64 a to 64 formed by trimming the resistor 64.
Since the resistance value is adjusted by c, the resistance value of the resistor 64 can be easily set to the optimum value, as in the above-described embodiments.
In addition, since the fusible alloy 68 is connected and fixed above the current path near the cuts 64a to 64c due to the trimming of the resistor 64, the heat generated by energization of the resistor 64 is efficiently increased. 68 to the resistor 64
The feature is that the fusible alloy 68 is surely melted and the circuit can be opened in a short time from the start of current supply. Further, since the electrodes 56 and 57, the resistor 64, the insulator layer 65, the fusible alloy 68 and the flux 69 are formed on one side of the insulating substrate 51, the protection element A shown in FIGS. 4 and FIG. 4 to FIG.
Is efficiently transmitted to the fusible alloy 68 thereon through the insulating layer 65 thinner than the insulating substrates 1 and 21, and the fusible alloy 6
8 has a feature that the circuit can be opened by fusing.

Although each of the above embodiments has been described with reference to a specific structure of the present invention, it is needless to say that various modifications can be made without departing from the spirit of the present invention. For example, in each of the above-described embodiments, when the insulating substrates 1, 21, 51 are formed in a dark system color (black) and the insulating caps 15, 36, 70 are formed in a white system color (white), the surface mounting is performed during surface mounting. Even when mounted through an infrared reflow furnace, the heat absorption of the insulating caps 15, 36, 70 is small and the heat absorption of the insulating substrates 1, 21, 51 is large, so that the internal fusible alloy 9, 34, 68 is erroneously melted. Surface mounting can be performed without any problem, the temperature can be quickly raised, and an infrared reflow furnace with high efficiency can be adopted, and the mounting method is not limited.

Further, in each of the above-mentioned embodiments, a space is provided above the fluxes 10, 35, 69 and covered with the plate-shaped or box-shaped insulating caps 15, 36, 70 made of a molded body and fixedly sealed. According to such a structure, when the fusible alloys 9, 34, 68 and the fluxes 10, 35, 69 can be melted, they can flow freely, so that the fusible alloys 9, 34, 68 Has the advantage that it can be reliably blown to provide a highly reliable protection element. However, a sufficiently thick flux may be covered with an insulating coating layer made of resin or the like.

Further, although not shown in the above embodiment, a plurality of fusible alloys are provided to control a multi-circuit, or a plurality of resistors are provided to improve the reliability of fusing of the fusible alloy. Thus, the reliability of the protection element can be improved.

[0045]

As described above, the present invention provides an insulating substrate, a resistor formed on one surface side of the insulating substrate, an insulator layer coated on the resistor, A fusible alloy formed on the other surface side of the substrate, wherein the resistor is trimmed, and the fusible alloy is formed corresponding to a position on a current path near a trimming portion of the resistor. The protection element is characterized in that the resistance value of the resistor can be set to the optimum value, and the heat generated by the resistor is efficiently transmitted to the fusible alloy, and a short time after the start of energization of the resistor Thus, it is possible to provide a protection element capable of fusing the fusible alloy. The present invention is also a method for manufacturing a protective element having a fusible alloy on an insulating substrate and a resistor forcibly blowing the fusible alloy by energizing heat generation, the step of forming a resistor on the insulating substrate, A method of manufacturing a protective element, which includes a step of forming an insulator layer on the resistor and a step of trimming the resistor by irradiating a laser from above the insulator layer, A method of manufacturing a protection element that can easily and reliably set the resistance value of a resistor to an optimum value can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a protection element A according to a first embodiment of the present invention, taken along a longitudinal central axis of an insulating substrate.

FIG. 2 is a plan view of the protection element A according to the first embodiment of the present invention before the application of the flux, that is, in a state where the insulating cap and the flux are removed so that the internal structure is visible.

FIG. 3 is a bottom view of the protection element A according to the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional view along a central axis in a longitudinal direction of a protection element B according to a second embodiment of the present invention.

FIG. 5 is a plan view of a protective element B according to a second embodiment of the present invention before the application of flux, that is, a state in which the insulating cap and the flux are removed so that the internal structure is visible.

FIG. 6 is a bottom view of the protection element B according to the second embodiment of the present invention in a state where a part is cut away.

FIG. 7 is a longitudinal sectional view of a protection element C according to a third embodiment of the present invention, taken along a central axis in a longitudinal direction.

FIG. 8 is a plan view of a protection element C according to a third embodiment of the present invention in which an insulating cap, flux, electrodes, and an insulating layer are removed so that the internal structure can be seen.

FIG. 9 is a plan view of a protection element C according to a third embodiment of the present invention in a state where an insulating cap, a flux, a fusible alloy, and an electrode are removed.

FIG. 10 is a plan view of a protective element C according to a third embodiment of the present invention before flux application, that is, a state in which the insulating cap and the flux are removed so that the internal structure is visible.

FIG. 11 is a bottom view of a protection element C according to a third embodiment of the present invention.

FIG. 12 is a plan view of a conventional protection element and a circuit diagram illustrating a method of using the protection element.

FIG. 13 is a longitudinal sectional view of a conventional protection element.

[Explanation of symbols]

1, 21, 51 insulating substrates 2, 3, 26, 27, 56, 57, 58, 59, 66,
67 electrodes 4, 5, 28, 29, 30, 31, 60, 61, 62,
63 terminal 6 insulating frame 7, 32, 64 resistor 7a, 7b, 32a, 32b, 64a, 64b, 64c
Cut by trimming 8, 33, 65 Insulator layer 9, 34, 68 Soluble alloy 10, 35, 69 Flux 11, 12, 38, 39, 40, 41, 72, 73, 7
4, 75 Solder layer 15, 36, 70 Insulating cap 16, 17 Sealing resin 22, 23, 24, 25, 52, 53, 54, 55 Notch 37, 71 Adhesive

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 12, 1999 (1999.3.1.
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

The invention according to claim 7 of the present invention is characterized in that said resistor
Lower melting point above insulator layer after body trimming
7. The semiconductor device according to claim 6, wherein said insulating layer is coated with said insulating layer.
It is a protection element of description.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

The invention according to claim 8 of the present invention provides an insulating substrate
The fusible alloy is forcibly melted by
A method of manufacturing a protection element having a resistor to be turned off.
Forming a resistor on the insulating substrate,
Forming an insulating layer, and laminating the insulating layer from above;
Of trimming the resistor by irradiating the
And a method for manufacturing a protection element.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

According to a ninth aspect of the present invention, there is provided a method of manufacturing a protective element having a fusible alloy and a resistor for forcibly blowing the fusible alloy by energizing and heating the insulating substrate. Forming a resistor on the resistor, forming an insulator layer on the resistor, trimming the resistor by irradiating a laser from above the insulator layer, And a step of forming an insulator layer.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0045

[Correction method] Change

[Correction contents]

[0045]

As described above, the present invention provides an insulating substrate, a resistor formed on one surface side of the insulating substrate, an insulator layer coated on the resistor, A fusible alloy formed on the other surface side of the substrate, wherein the resistor is trimmed, and the fusible alloy is formed corresponding to a position on a current path near a trimming portion of the resistor. The protection element is characterized in that the resistance value of the resistor can be set to the optimum value, and the heat generated by the resistor is efficiently transmitted to the fusible alloy, and a short time after the start of energization of the resistor Thus, it is possible to provide a protection element capable of fusing the fusible alloy. Book
The invention also includes an insulating substrate, and one surface side of the insulating substrate.
The formed resistor and the coating formed on this resistor
An insulator layer and a fusible alloy formed on the insulator layer;
Wherein the resistor has been trimmed,
The fusible alloy is the upper current path near the trimming part of the resistor.
Protection element characterized in that it is formed corresponding to the location
Therefore, the resistance value of the resistor can be set to the optimum value.
Can efficiently generate heat from the resistor without going through the insulating substrate
It is transmitted to the molten alloy and is possible in a short time from the start of energizing the resistor.
A protective element capable of fusing the molten alloy can be provided. According to the present invention
Further, a method for manufacturing a protective element having a fusible alloy on the insulating substrate and a resistor forcibly blowing the fusible alloy by energizing heat generation, a step of forming a resistor on the insulating substrate,
A method of manufacturing a protective element, which includes a step of forming an insulator layer on the resistor and a step of trimming the resistor by irradiating a laser from above the insulator layer, A method of manufacturing a protection element that can easily and reliably set the resistance value of a resistor to an optimum value can be provided.

Claims (10)

[Claims] 1. An insulating substrate, a resistor formed on one surface of the insulating substrate, an insulator layer coated on the resistor, and a resistor formed on the other surface of the insulating substrate. Wherein the resistor is trimmed, and the fusible alloy is formed corresponding to a position on a current path near a trimming portion of the resistor. Protection element. 2. An insulating substrate, a resistor formed on one surface of the insulating substrate, an insulator layer formed on the resistor, and a resistor formed on the insulator layer. And a fusible alloy, wherein the resistor is trimmed, and the fusible alloy is formed corresponding to a position on a current path near a trimming portion of the resistor. 3. The protection element according to claim 1, wherein the trimming of the resistor is performed in a direction orthogonal to a current direction of the resistor. 4. The protection element according to claim 3, wherein said resistor is trimmed at a plurality of positions on said resistor. 5. The protection element according to claim 4, wherein the trimming of the resistor is performed on the insulator layer. 6. The protection element according to claim 5, wherein an upper portion of the insulator layer after trimming the resistor is further covered with an insulator layer. 7. The protection element according to claim 6, wherein the insulator layer after trimming of the resistor is further covered with an insulator layer having a lower melting point. 8. A method for manufacturing a protection element having a fusible alloy on an insulating substrate and a resistor forcibly blowing the fusible alloy by energizing heat, comprising: forming a resistor on the insulating substrate; A method for manufacturing a protective element, comprising: a step of forming an insulator layer on a resistor; and a step of trimming the resistor by irradiating a laser from above the insulator layer. 9. A method for manufacturing a protection element having a fusible alloy on an insulating substrate and a resistor for forcibly blowing the fusible alloy by energization and heat generation, comprising: forming a resistor on the insulating substrate; A step of forming an insulator layer on the resistor, a step of trimming the resistor by irradiating a laser from above the insulator layer, and a step of further forming an insulator layer on the insulator layer A method for manufacturing a protection element, comprising: 10. A method of manufacturing a protective element having a fusible alloy on an insulating substrate and a resistor for forcibly blowing the fusible alloy by heat generated by current flow, comprising: forming a resistor on the insulating substrate; A step of forming an insulator layer on the resistor, a step of trimming the resistor by irradiating a laser from above the insulator layer, and an insulator having a lower melting point than the insulator on the insulator layer. A method of manufacturing a protection element, comprising: forming a layer; and connecting and fixing a fusible alloy at a position corresponding to a current path of a trimmed resistor.