JP2006073331A

JP2006073331A - Fuse element

Info

Publication number: JP2006073331A
Application number: JP2004254663A
Authority: JP
Inventors: Kengo Hirose; 健吾廣瀬
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-09-01
Filing date: 2004-09-01
Publication date: 2006-03-16
Anticipated expiration: 2024-09-01
Also published as: JP4386274B2

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that it was impossible to realize a fuse element of which the rated current capacity per sheet of the same size is large with an I<SP>2</SP>t value made small because the I<SP>2</SP>t value becomes large in proportion to the square of the total minimum cross sectional area ΣS in a conventional fuse element. <P>SOLUTION: The fuse element 21 is constituted by forming a conductive thin film 23 on the surface of a rectangular plate ceramic substrate 22 having electrically insulating characteristics. As for the conductive thin film 23, a copper foil or the like existing in 9 pieces of oval parts 23a and half-ellipse parts 23b on these both sides is removed by etching, and this parallel intercepting part 23c in which 10 pieces of a narrow and small part P of which the cross-sectional area is made narrow and small are electrically arranged in parallel is formed furthermore. Other 5 pieces of these parallel intercepting parts 23c are electrically arranged in series. Furthermore, the thickness excluding the parallel intercepting part 23c is formed thinner in comparison with the thickness of the other part of the parallel intercepting part 23c, and the number P<SB>B</SB>of the narrow and small part P is numerously formed based on this share of which the thickness has been reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、導電性薄膜の断面積が狭小にされた狭小部が電気的に並列に配置されて並列遮断部が形成され、さらに、この並列遮断部が電気的に直列に配置されて基板表面に形成されるヒューズエレメントに関するものである。 In the present invention, the narrow portions of the conductive thin film having a reduced cross-sectional area are electrically arranged in parallel to form a parallel cut-off portion, and the parallel cut-off portions are electrically arranged in series to form a substrate surface. The present invention relates to a fuse element formed in

従来、この種のヒューズエレメントとしては、例えば、図１（ａ）に示すエッチング・ヒューズエレメント１がある。 Conventionally, as this type of fuse element, for example, there is an etching fuse element 1 shown in FIG.

このエッチング・ヒューズエレメント１は、電気的絶縁性を有する長方形の板状をしたセラミック基板２の表面に、導電性薄膜３が形成されて構成されており、ヒューズ筒中に消弧砂に埋められて収納される。導電性薄膜３は銅箔や銀箔等からなり、図示するようにエッチングされてパターンニングされている。このパターンニングにより、４個の楕円部３ａおよびこの両側の半楕円部３ｂにある銅箔等がエッチングによって除去され、導電性薄膜３には、断面積が狭小にされた狭小部Ｐが５個電気的に並列に配置された並列遮断部３ｃが形成されている。この並列遮断部３ｃはさらに５個電気的に直列に配置され、狭小部Ｐは、５個直列(Sereis)で５個並列(Parallel)、つまり、５Ｓ５Ｐにパターンニングされている。 This etching fuse element 1 is formed by forming a conductive thin film 3 on the surface of a rectangular ceramic substrate 2 having electrical insulation, and is buried in arc-extinguishing sand in a fuse cylinder. Stored. The conductive thin film 3 is made of a copper foil, a silver foil, or the like, and is etched and patterned as shown. By this patterning, the copper foils and the like in the four ellipsoidal portions 3a and the semi-elliptical portions 3b on both sides thereof are removed by etching, and the conductive thin film 3 has five narrow portions P whose sectional areas are narrowed. A parallel blocking portion 3c arranged in parallel electrically is formed. Further, five parallel blocking portions 3c are electrically arranged in series, and the narrow portion P is patterned in five parallel (Sereis), five parallel, that is, 5S5P.

通電電流はヒューズエレメント１の導電性薄膜３を通常流れているが、事故電流が発生すると、断面積が小さくて抵抗値の高い各狭小部Ｐが溶断し、アーク電圧が高まって事故電流が速やかに遮断される。 The energizing current normally flows through the conductive thin film 3 of the fuse element 1. However, when an accident current occurs, each narrow portion P having a small cross-sectional area and a high resistance value is melted, the arc voltage increases, and the accident current is quickly generated. Will be blocked.

また、従来、図１（ｂ）に示すリボン型のヒューズエレメント１１もある。このヒューズエレメント１１は、銀（Ａｇ）リボンがプレス金型によって図示するように打ち抜かれ、銀リボンの断面積が狭小にされた狭小部Ｐが５個直列で４個並列、つまり、５Ｓ４Ｐの形状にパターンニングされている。 Conventionally, there is also a ribbon-type fuse element 11 shown in FIG. The fuse element 11 has a silver (Ag) ribbon punched out by a press die as shown in the figure, and five narrow portions P in which the cross-sectional area of the silver ribbon is narrowed in series are four in parallel, that is, a shape of 5S4P. Has been patterned.

このヒューズエレメント１１も、ヒューズ筒中に消弧砂に埋められて収納される。通電電流はヒューズエレメント１１を通常流れているが、事故電流が発生すると、断面積が小さくて抵抗値の高い各狭小部Ｐが溶断し、アーク電圧が高まって事故電流が速やかに遮断される。 This fuse element 11 is also housed in a fuse cylinder buried in arc-extinguishing sand. The energizing current normally flows through the fuse element 11, but when an accident current occurs, each narrow portion P having a small cross-sectional area and a high resistance value is melted, the arc voltage is increased, and the accident current is quickly cut off.

これらヒューズエレメント１，１１を用いた電力用限流ヒューズ、特に半導体保護用ヒューズにおいては、限流性能を示す代表値として、遮断電流Ｉの二乗値（Ｉ^２ｄｔ）を遮断時間０〜ｔで積分したＩ^２ｔ値が採用され、また、その参考値として、並列遮断部における各狭小部Ｐの断面積Ｓの総和（Σ）に相当するヒューズエレメント１，１１の総合最小断面積ΣＳが使用される場合が多い。 In the current limiting fuse for electric power using these fuse elements 1 and 11, especially the fuse for semiconductor protection, as a representative value indicating the current limiting performance, the square value (I ² dt) of the interrupting current I is expressed by the interrupting time 0 to t. The integrated I ² t value is adopted, and the total minimum cross-sectional area ΣS of the fuse elements 1 and 11 corresponding to the sum (Σ) of the cross-sectional areas S of the narrow portions P in the parallel interrupting section is used as a reference value. Often done.

図２（ａ）は、これら従来のヒューズエレメント１，１１を用いた半導体保護用ヒューズの遮断電圧波形であり、縦軸は電圧ｖ，横軸は時間ｔを表す。また、同図（ｂ）は同ヒューズ１，１１の遮断電流波形を示すグラフであり、縦軸は電流ｉ，横軸は時間ｔを表す。これらグラフに示すように、時刻ｔ_０に短絡電流が発生すると、各狭小部Ｐに大電流が流れることによって各狭小部Ｐは熱せられ、時刻ｔ_１に各狭小部Ｐは溶断する。各狭小部Ｐが溶断するとアークが発生し、商用周波５０[Hz]の電圧波形Ｖは電圧値Ｖｍまで急峻に立ち上がるアーク電圧となり、時刻ｔ_２で遮断が行われる。遮断が行われると、電流波形Ｉは急速に減少して電流値Ｉｍに限流され、時刻ｔ_３において電流値が０となって遮断が完了する。 FIG. 2A shows a cutoff voltage waveform of a semiconductor protection fuse using these conventional fuse elements 1 and 11, where the vertical axis represents voltage v and the horizontal axis represents time t. FIG. 4B is a graph showing the breaking current waveform of the fuses 1 and 11, where the vertical axis represents current i and the horizontal axis represents time t. As shown in these graphs, when a short-circuit current occurs at time t ₀ , each narrow portion P is heated by a large current flowing through each narrow portion P, and each narrow portion P is fused at time t ₁ . When the narrow portion P is blown arc is generated, the voltage waveform V of the commercial frequency 50 [Hz] becomes the arc voltage rises sharply up to the voltage value Vm, blocking is performed at time t _2. When blocking occurs, the current waveform I is flowed limited to the current value Im decreases rapidly, the current value at time t ₃ is 0 when the shut-off is completed.

溶断後のアーク電圧の立ち上がりはほとんど垂直に近く、アーク電圧が電源電圧まで立ち上がったところで限流されるのが理屈であるが、溶断時刻ｔ_１と限流時刻ｔ_２との時間差は数μｓｅｃ以下で、その差はほとんど認められない。従って、溶断時刻ｔ_１を限流時刻ｔ_２としても大きな間違いとはならない。また、短絡電流の突進率は極めて大きく、約１１．１×１０^６〜４４．４×１０^６Ａ／ｓｅｃもあるので、溶断は、各狭小部Ｐが断熱的に熱せられて起こり、発生した熱が消弧砂に逃げることなく、発弧に至るものと考えられる。従って、溶断時に各狭小部Ｐが吸収する熱の容量を決めるヒューズエレメント１，１１の総合最小断面積ΣＳは、ヒューズの限流特性を予測する参考値と考えられる。すなわち、総合最小断面積ΣＳは電流波形Ｉから計算されるＩ^２ｔ値と比例関係にあり、総合最小断面積ΣＳの二乗に比例してＩ^２ｔ値も大きくなると考えられている。 The rise of the arc voltage after fusing is almost vertical, and it is logical that the current is limited when the arc voltage rises to the power supply voltage, but the time difference between the fusing time t ₁ and the current limiting time t ₂ is several μsec or less. The difference is hardly recognized. Therefore, even if the fusing time t ₁ is set as the current limiting time t ₂ , it is not a big mistake. Moreover, since the rush rate of the short-circuit current is extremely large and is about 11.1 × 10 ^{6 to} 44.4 × 10 ⁶ A / sec, the fusing occurred as each narrow portion P was adiabatically heated and occurred. It is thought that the heat reaches the arc without escaping to the arc-extinguishing sand. Therefore, the total minimum cross-sectional area ΣS of the fuse elements 1 and 11 that determines the capacity of heat absorbed by each narrow portion P at the time of fusing is considered to be a reference value for predicting the current limiting characteristics of the fuse. That is, the total minimum cross-sectional area ΣS is proportional to the I ² t value calculated from the current waveform I, and it is considered that the I ² t value increases in proportion to the square of the total minimum cross-sectional area ΣS.

ヒューズエレメント１，１１を製作するうえで、同じ大きさで１枚当たりの定格電流容量を大きくすることは、ヒューズの製造コストを下げるうえで重要であるが、Ｉ^２ｔ値を大きくすることなく、つまり、限流性能を低下させることなく、これを実現することが重要である。定格電流容量を大きくするには、導電性薄膜３や銀リボンといったヒューズリンクのＷ（ワット）損を小さくするため、総合最小断面積ΣＳを大きくする必要がある。しかし、上記従来のヒューズエレメント１，１１では、上述したように、総合最小断面積ΣＳの二乗に比例してＩ^２ｔ値も大きくなるため、同じ大きさで１枚当たりの定格電流容量が大きいヒューズエレメントを限流性能を低下させることなく実現することは至難であった。 When manufacturing the fuse elements 1 and 11, increasing the rated current capacity per sheet with the same size is important for reducing the manufacturing cost of the fuse, but without increasing the I ² t value. In other words, it is important to realize this without degrading the current limiting performance. In order to increase the rated current capacity, it is necessary to increase the total minimum cross-sectional area ΣS in order to reduce the W (watt) loss of the fuse link such as the conductive thin film 3 and the silver ribbon. However, in the conventional fuse elements 1 and 11, as described above, the I ² t value also increases in proportion to the square of the total minimum cross-sectional area ΣS, so that the rated current capacity per sheet is large with the same size. It has been difficult to realize the fuse element without degrading the current limiting performance.

本発明はこのような課題を解決するためになされたもので、電気的絶縁性を有する基板と、断面積が狭小にされた狭小部が電気的に並列に配置された並列遮断部が電気的に直列に配置されて基板表面に形成された導電性薄膜とから構成されるヒューズエレメントにおいて、導電性薄膜は、狭小部の断面積が小さく形成され、この断面積が小さくされた分に基づいて狭小部の個数が多く形成されて、狭小部の総合最小断面積が、狭小部の増加前後の個数比に逆比例した値を最小値とした狭小部の断面積と、狭小部の増加後の個数との積に設定されていることを特徴とする。 The present invention has been made to solve such a problem, and an electrically insulating substrate and a parallel blocking portion in which a narrow portion having a narrow cross-sectional area is electrically arranged in parallel are electrically connected. In the fuse element composed of the conductive thin film arranged in series on the substrate surface, the conductive thin film has a narrow cross-sectional area formed on the basis of the reduced cross-sectional area. A large number of narrow portions are formed, and the total minimum cross-sectional area of the narrow portion is the cross-sectional area of the narrow portion with the minimum value that is inversely proportional to the number ratio before and after the increase of the narrow portion, and after the increase of the narrow portion It is characterized by being set to the product of the number.

この構成によれば、狭小部Ｐの断面積Ｓは、狭小部Ｐの増加前の個数をＰ_Ａ、増加後の個数をＰ_Ｂとすると、狭小部Ｐの増加前後の個数比（Ｐ_Ｂ／Ｐ_Ａ）に逆比例（Ｐ_Ａ／Ｐ_Ｂ）した断面積、つまり、Ｓ×（Ｐ_Ａ／Ｐ_Ｂ）を最小値として設定される。従って、各狭小部Ｐの断面積の総和である総合最小断面積ΣＳ（＝Ｓ×Ｐ_Ａ）を同等のΣＳ（＝Ｓ×（Ｐ_Ａ／Ｐ_Ｂ）×Ｐ_Ｂ）、またはこれ以上に設定しながら、狭小部Ｐの個数を増やすことが出来る。また、導電性薄膜は、砂粒の間に空隙があって熱伝導性の悪い従来の消弧砂とは異なり、基板に密着しているため、導電性薄膜で生じた熱は速やかに基板に放散する。このため、総合最小断面積ΣＳを同等または同等以上にしながら狭小部Ｐの個数を増やすことにより、事故電流の遮断時に各狭小部Ｐに発生する熱を基板に放散することの出来る箇所が増え、放熱量を増大させるため、遮断電流の限流値Ｉｍを従来よりも低い値に抑えることができる。この結果、総合最小断面積ΣＳの二乗値とＩ^２ｔ値とは比例すると考えられていた従来の常識に反し、総合最小断面積ΣＳを同等または同等以上にして、定格電流容量を同じかまたはより大きく確保しながら、Ｉ^２ｔ値を小さくすることが可能なヒューズエレメントが提供される。 According to this configuration, the cross-sectional area S of the narrow portion P has a number ratio (P _B / _B) before and after the increase of the narrow portion P, where P _{A is} the number before the narrow portion P is increased and P _B is the number after the increase. _A cross-sectional area inversely proportional to (P _A ) (P _A / P _B ), that is, S × (P _A / P _B ) is set as a minimum value. Accordingly, the total minimum cross-sectional area ΣS (= S × P _A ), which is the sum of the cross-sectional areas of the respective narrow portions P, is set to an equivalent ΣS (= S × (P _A / P _B ) × P _B ) or more. However, the number of the narrow portions P can be increased. In addition, unlike conventional arc-extinguishing sand, where the conductive thin film has voids between the sand grains and has poor thermal conductivity, the conductive thin film is in close contact with the substrate, so the heat generated in the conductive thin film is quickly dissipated to the substrate. To do. For this reason, by increasing the number of the narrow portions P while making the total minimum cross-sectional area ΣS equal or equal to or greater, the number of places where the heat generated in each narrow portion P can be dissipated to the substrate when the fault current is interrupted is increased. Since the heat radiation amount is increased, the current limiting value Im of the breaking current can be suppressed to a value lower than that of the conventional one. As a result, contrary to the conventional common sense that the square value of the total minimum cross-sectional area ΣS and the I ² t value are considered to be proportional, the total minimum cross-sectional area ΣS is made equal to or equal to or higher, and the rated current capacity is the same or A fuse element capable of reducing the I ² t value while ensuring a larger value is provided.

また、本発明は、導電性薄膜が、狭小部間のピッチが各狭小部の冷却特性の独立性を失わないところまで狭く形成され、この狭くされた分に基づいて狭小部の個数が多く形成されていることを特徴とする。 Further, according to the present invention, the conductive thin film is formed so narrow that the pitch between the narrow portions does not lose the independence of the cooling characteristics of each narrow portion, and the number of the narrow portions is formed based on the narrowed portion. It is characterized by being.

この構成によれば、各狭小部Ｐ間のピッチが狭く形成されて１個当たりの狭小部Ｐの断面積が小さくされ、この小さくされた断面積の分に基づいて狭小部Ｐの個数が多く形成されることにより、Ｉ^２ｔ値を小さくしながら総合最小断面積ΣＳを同等または同等以上に設定することが出来る。 According to this configuration, the pitch between the narrow portions P is narrowed to reduce the cross-sectional area of each narrow portion P, and the number of the narrow portions P is large based on the reduced cross-sectional area. By being formed, the total minimum cross-sectional area ΣS can be set to be equal to or greater than or equal to the value while reducing the I ² t value.

また、本発明は、導電性薄膜が、並列遮断部の厚さが並列遮断部以外の厚さに比較して薄く形成され、この薄くされた分に基づいて狭小部の個数が多く形成されていることを特徴とする。 Further, according to the present invention, the conductive thin film is formed such that the thickness of the parallel blocking portion is smaller than the thickness other than the parallel blocking portion, and the number of narrow portions is formed based on the thinned portion. It is characterized by being.

この構成によれば、並列遮断部の厚さが薄く形成されて１個当たりの狭小部Ｐの断面積が小さくされ、この小さくされた断面積の分に基づいて狭小部Ｐの個数は、上記の狭小部間のピッチが狭く形成される場合よりもさらに多く形成される。そして、狭小部Ｐの個数が多く形成されることにより、Ｉ^２ｔ値を小さくしながら総合最小断面積ΣＳを同等または同等以上に設定することが出来る。このように導電性薄膜の一部分を薄くする構造は、極薄い銀リボンをプレス成型して形成するヒューズエレメントでは実現し得ない。 According to this configuration, the thickness of the parallel blocking portions is formed thin, and the cross-sectional area of each narrow portion P is reduced. Based on the reduced cross-sectional area, the number of the narrow portions P is as described above. It is formed more than the case where the pitch between the narrow portions is narrow. Then, by forming a large number of narrow portions P, it is possible to set the total minimum cross-sectional area ΣS to be equal to or equal to or greater than that while reducing the I ² t value. Such a structure in which a part of the conductive thin film is thinned cannot be realized by a fuse element formed by press-molding an extremely thin silver ribbon.

このように本発明によれば、上記のように、総合最小断面積ΣＳの二乗値とＩ^２ｔ値とは比例すると考えられていた従来の常識に反し、総合最小断面積ΣＳを同等または同等以上にして、定格電流容量が同じかまたはより大きいヒューズエレメントを同じ大きさでしかもＩ^２ｔ値特性のよりよいものを実現することが可能となる。 Thus, according to the present invention, as described above, the square value of the total minimum cross-sectional area ΣS and the I ² t value are contrary to conventional common sense, which is considered to be proportional, and the total minimum cross-sectional area ΣS is equal or equivalent. As described above, fuse elements having the same or larger rated current capacity and having the same size and better I ² t value characteristics can be realized.

次に、本発明を実施するための最良の形態について説明する。 Next, the best mode for carrying out the present invention will be described.

図３は、本実施形態によるエッチング・ヒューズエレメント２１の平面図である。 FIG. 3 is a plan view of the etching fuse element 21 according to the present embodiment.

このエッチング・ヒューズエレメント２１は、電気的絶縁性を有する長方形の板状をした厚さ１[ｍｍ]のセラミック基板２２の表面に、導電性薄膜２３が形成されて構成されており、ヒューズ筒中に消弧砂に埋められて収納される。導電性薄膜２３は銅箔や銀箔等からなり、図示するようにエッチングされてパターンニングされている。このパターンニングにより、９個の楕円部２３ａおよびこの両側の半楕円部２３ｂにある銅箔等がエッチングによって除去され、導電性薄膜２３には、断面積が狭小にされた狭小部Ｐが１０個電気的に並列に配置された並列遮断部２３ｃが形成されている。この並列遮断部２３ｃはさらに５個電気的に直列に配置され、狭小部Ｐは、５個直列(Sereis)で１０個並列(Parallel)、つまり、５Ｓ１０Ｐにパターンニングされている。 This etching fuse element 21 is configured by forming a conductive thin film 23 on the surface of a ceramic substrate 22 having a thickness of 1 [mm] in the form of a rectangular plate having electrical insulation properties. It is buried in arc-extinguishing sand and stored. The conductive thin film 23 is made of copper foil, silver foil, or the like, and is etched and patterned as shown in the figure. By this patterning, the copper foils and the like in the nine ellipsoidal portions 23a and the semi-elliptical portions 23b on both sides are removed by etching, and the conductive thin film 23 has ten narrow portions P with a narrow cross-sectional area. A parallel blocking portion 23c is formed which is electrically arranged in parallel. Further, five parallel cut-off portions 23c are electrically arranged in series, and the narrow portion P is patterned in five parallel (Sereis), 10 parallel (Parallel), that is, 5S10P.

また、本実施形態では、導電性薄膜２３が、エッチングにより、並列遮断部２３ｃの厚さが並列遮断部２３ｃ以外の厚さに比較して薄く形成され、この薄くされた分に基づいて狭小部Ｐの個数Ｐ_Ｂが図１（ａ）に示す従来のエッチング・ヒューズエレメント１の個数Ｐ_Ａよりも５個多く形成されている。 Further, in the present embodiment, the conductive thin film 23 is formed by etching so that the thickness of the parallel blocking portion 23c is thinner than the thickness other than the parallel blocking portion 23c, and a narrow portion is formed based on the thinned portion. P number P _B is formed of five larger than the number P _a of Figure 1 a conventional etch fuse element 1 shown in (a).

つまり、本実施形態のヒューズエレメント２１の導電性薄膜２３は、並列遮断部２３ｃの厚さｔ_Ｂが４０[μ]、並列遮断部２３ｃ以外の厚さが１００[μ]となっており、楕円部２３ａ間の間隔、つまり、狭小部Ｐの幅ｂ_Ｂが８０[μ]となっている。このように導電性薄膜２３の一部分を薄くする構造は、銀リボンをプレス成型して形成する従来のヒューズエレメントでは、穴径に制約があり、余り大きなＰ値を採用できないばかりか、厚さが８０[μ]以上で一定で１つのパターン内に厚さの大小をつけることが出来ず、実現し得ない。従って、狭小部Ｐの断面積Ｓ_Ｂはｔ_Ｂ×ｂ_Ｂ＝４０[μ]×８０[μ]となり、総合最小断面積ΣＳ_Ｂはｔ_Ｂ×ｂ_Ｂ×Ｐ_Ｂ＝４０[μ]×８０[μ]×１０＝３２０００×１０^−１２となる。また、図１（ａ）に示す従来のエッチング・ヒューズエレメント１の導電性薄膜３は、厚さｔ_Ａが５０[μ]で均一となっており、楕円部３ａ間の間隔、つまり、狭小部Ｐの幅ｂ_Ａが１００[μ]となっている。従って、狭小部Ｐの断面積Ｓ_Ａはｔ_Ａ×ｂ_Ａ＝５０[μ]×１００[μ]となり、総合最小断面積ΣＳ_Ａはｔ_Ａ×ｂ_Ａ×Ｐ_Ａ＝５０[μ]×１００[μ]×５＝２５０００×１０^−１２となる。 That is, in the conductive thin film 23 of the fuse element 21 of the present embodiment, the thickness t _B of the parallel blocking portion 23c is 40 [μ], and the thickness other than the parallel blocking portion 23c is 100 [μ]. The interval between the portions 23a, that is, the width b _B of the narrow portion P is 80 [μ]. In this way, the structure in which a part of the conductive thin film 23 is thinned has a limitation in the hole diameter in the conventional fuse element formed by press-molding a silver ribbon. It is constant at 80 [μ] or more, and the thickness cannot be set in one pattern and cannot be realized. Therefore, the cross-sectional area _{S B} of the narrow portion P is _{_{t B × b B = 40 [}} μ] × 80 [μ] , and the total minimum cross-sectional area [sigma] s _B is _{_{_{t B × b B × P B}}} = 40 [μ] × 80 [μ] × 10 = 32000 × 10 ⁻¹² Further, the conductive thin film 3 of the conventional etching fuse element 1 shown in FIG. 1A has a uniform thickness t _A of 50 [μ], and the interval between the ellipsoidal portions 3a, that is, a narrow portion. The width b _{A of} P is 100 [μ]. Accordingly, the cross-sectional area S _A of the narrow portion P is t _A × b _A = 50 [μ] × 100 [μ], and the total minimum cross-sectional area ΣS _A is t _A × b _A × P _A = 50 [μ] × 100. [μ] × 5 = 25000 × 10 ⁻¹²

総合最小断面積ΣＳはヒューズエレメントの定格電流に比例する。従って、本実施形態のヒューズエレメント２１の定格電流は、計算式（ΣＳ_Ｂ／ΣＳ_Ａ）^１／２＝（３２０００×１０^−１２／２５０００×１０^−１２）^１／２＝１．１３により、従来のヒューズエレメント１の定格電流の１．１３倍になっている。 The total minimum sectional area ΣS is proportional to the rated current of the fuse element. Therefore, the rated current of the fuse element 21 of the present embodiment is calculated according to the calculation formula (ΣS _B / ΣS _A ) ^1/2 = (32000 × 10 ⁻¹² / 25000 × 10 ⁻¹² ) ^1/2 = 1.13. This is 1.13 times the rated current of the fuse element 1.

また、本実施形態のヒューズエレメント２１は、狭小部Ｐの増加前の個数Ｐ_Ａが従来のヒューズエレメント１の５、増加後の個数Ｐ_Ｂが１０であり、並列遮断部２３ｃの導電性薄膜３の厚さｔ_Ｂ（４０[μ]）は、狭小部Ｐの増加前後の個数比（Ｐ_Ｂ／Ｐ_Ａ＝１０／５）に逆比例（Ｐ_Ａ／Ｐ_Ｂ＝５／１０）した厚さ（ｔ_Ａ×（Ｐ_Ａ／Ｐ_Ｂ）＝５０[μ]×５／１０＝２５[μ]）を最小値として設定されている。従って、本実施形態のヒューズエレメント２１は、厚さｔ_Ｂ（４０[μ]）に狭小部Ｐの幅ｂ_Ｂ（８０[μ]）を乗算して得られる狭小部Ｐの断面積Ｓ_Ｂ（＝３２００×１０^−１２）が、狭小部Ｐの増加前後の個数比（Ｐ_Ｂ／Ｐ_Ａ＝１０／５）に逆比例（Ｐ_Ａ／Ｐ_Ｂ＝５／１０）した値（Ｓ_Ａ×（Ｐ_Ａ／Ｐ_Ｂ）＝５０００×１０^−１２×５／１０＝２５００×１０^−１２）を最小値として設定されていることになる。 In the fuse element 21 of the present embodiment, the number P _A before the increase of the narrow portion P is 5 of the conventional fuse element 1 and the number P _B after the increase is 10, and the conductive thin film 3 of the parallel blocking portion 23c. The thickness t _B (40 [μ]) is a thickness inversely proportional to the number ratio (P _B / P _A = 10/5) before and after the increase in the narrow portion P (P _A / P _B = 5/10). _{_{_{(t a × (P a /}}} P B) = 50 [μ] × 5/10 = 25 [μ]) is a is set as the minimum value. Therefore, the fuse element 21 of the present embodiment has a cross-sectional area S _B (narrow portion P _B ) obtained by multiplying the thickness t _B (40 [μ]) by the width b _B (80 [μ]) of the narrow portion P. = 3200 × 10 ⁻¹² ) is a value (S _A × (S _A × (10)) that is inversely proportional (P _A / P _B = ^5/10 ) to the number ratio (P _B / P _A = ^10/5 ) before and after the increase of the narrow portion P. P _A / P _B ) = 5000 × 10 ⁻¹² × ^5/10 = 2500 × 10 ⁻¹² ) is set as the minimum value.

しかし、ここで、並列遮断部２３ｃの導電性薄膜３の厚さｔ_Ｂを、狭小部Ｐの増加前後の個数比（Ｐ_Ｂ／Ｐ_Ａ＝１０／５）に逆比例（Ｐ_Ａ／Ｐ_Ｂ＝５／１０）した厚さと等しくし（ｔ_Ｂ＝２５[μ]）、狭小部Ｐの断面積Ｓ_Ｂを、狭小部Ｐの増加前後の個数比（Ｐ_Ｂ／Ｐ_Ａ＝１０／５）に逆比例（Ｐ_Ａ／Ｐ_Ｂ＝５／１０）した断面積と等しくすることにより（Ｓ_Ｂ＝２５００×１０^−１２）、本実施形態のヒューズエレメント２１の定格電流を、従来のヒューズエレメント１の定格電流と等しく設定することが出来る（ΣＳ_Ｂ＝２５００×１０^−１２×１０＝ΣＳ_Ａ）。 However, here, the thickness t _B of the conductive thin film 3 of the parallel blocking portion 23c is inversely proportional to the number ratio (P _B / P _A = 10/5) before and after the increase of the narrow portion P (P _A / P _B = 5/10) was equal to the thickness _{(t B = 25 [μ]} ), the cross-sectional area _{S B} of the narrow portion P, increased before and after the number ratio of the narrow portion _{_{P (P B / P a =}} 10/5) (S _B = 2500 × 10 ⁻¹² ) to make the rated current of the fuse element 21 of the present embodiment the conventional fuse element 1 by making it equal to the cross-sectional area inversely proportional to (P _A / P _B = ^5/10 ). Can be set equal to the rated current (ΣS _B = 2500 × 10 ⁻¹² × 10 = ΣS _A ).

また、本実施形態のヒューズエレメント２１のＩ^２ｔ値は、従来のヒューズエレメント１のＩ^２ｔ値の０．２５倍となっている。すなわち、本実施形態のヒューズエレメント２１は、上述したように、並列遮断部２３ｃの厚さが並列遮断部２３ｃ以外の厚さに比較して薄く形成され、この薄くされた分に基づいて狭小部Ｐの個数Ｐ_Ｂ（＝１０）が従来のエッチング・ヒューズエレメント１の個数Ｐ_Ａ（＝５）よりも多く形成されているため、本実施形態のヒューズエレメント２１のＩ^２ｔ値は、従来のヒューズエレメント１のＩ^２ｔ値と比較して、狭小部Ｐの増加前後の個数比（Ｐ_Ｂ／Ｐ_Ａ＝１０／５）の逆比（Ｐ_Ａ／Ｐ_Ｂ＝５／１０）の二乗倍（（５／１０）^２＝０．２５倍）になっている。 Also, ^{I 2} t value of the fuse element 21 of the present embodiment has a 0.25 times the conventional ^{I 2} t value of the fuse element 1. That is, in the fuse element 21 of the present embodiment, as described above, the thickness of the parallel blocking portion 23c is formed thinner than the thickness other than the parallel blocking portion 23c, and the narrow portion is formed based on the thinned portion. since the P number _P B (= 10) is formed larger than the conventional etch-fuse element 1 number _{^{P a (= 5), I}} 2 t value of the fuse element 21 of the present embodiment, the conventional Compared with the I ² t value of the fuse element 1, the square ratio of the inverse ratio (P _A / P _B = 5/10) of the number ratio (P _B / P _A = 10/5) before and after the increase of the narrow portion P ((5/10) ² = 0.25 times).

これは、ヒューズリンクを構成する導電性薄膜２３が、セラミック基板２２の表面と分子的に結合してセラミック基板２２に密着しているため、砂粒の間に空隙があって熱伝導性の悪い従来の消弧砂とは異なり、導電性薄膜２３で生じた熱が速やかにセラミック基板２２に放散するためであると考えられる。このため、総合最小断面積ΣＳ_Ｂを総合最小断面積ΣＳ_Ａと同等または同等以上にしながら、狭小部Ｐの個数をＰ_ＡからＰ_Ｂに増やすことにより、事故電流の遮断時に各狭小部Ｐに発生する熱をセラミック基板２２に放散することの出来る箇所が増え、放熱量を増大させるため、遮断電流の限流値Ｉｍを従来よりも低い値に抑えることができる。この結果、総合最小断面積ΣＳ_Ｂを総合最小断面積ΣＳ_Ａと同等または同等以上にして、定格電流容量を同じかまたはより大きく確保しながら、ヒューズエレメント１と同じ大きさでしかもＩ^２ｔ値を小さくすることが可能なヒューズエレメント２１を実現できる。 This is because the conductive thin film 23 constituting the fuse link is molecularly bonded to the surface of the ceramic substrate 22 and is in close contact with the ceramic substrate 22, so that there is a gap between sand grains and the heat conductivity is poor. Unlike the arc extinguishing sand, it is considered that the heat generated in the conductive thin film 23 is quickly dissipated to the ceramic substrate 22. Thus, while the total minimum cross-sectional area [sigma] s _B comprehensive minimum sectional area [sigma] s _A equal to or more than equivalent, the number of the narrow portion P by increasing the P _A to P _B, when interrupting the accident current to each narrow portion P Since the number of locations where the generated heat can be dissipated to the ceramic substrate 22 is increased and the amount of heat radiation is increased, the current limiting value Im of the breaking current can be suppressed to a value lower than the conventional value. As a result, the total minimum cross-sectional area ΣS _B is made equal to or greater than or equal to the total minimum cross-sectional area ΣS _A , while ensuring the same or larger rated current capacity, the same size as the fuse element 1 and the I ² t value Can be realized.

このようなヒューズエレメント２１を実現することが出来たのは、総合最小断面積ΣＳの二乗値とＩ^２ｔ値とは比例すると考えられていた従来の常識に反し、Ｉ^２ｔ値は、狭小部Ｐの増加前後の個数比（Ｐ_Ｂ／Ｐ_Ａ）の逆比（Ｐ_Ａ／Ｐ_Ｂ）の二乗（（Ｐ_Ａ／Ｐ_Ｂ）^２）倍になるということを、出願人が以下の実験によって見いだしたからである。 The fuse element 21 can be realized because the square value of the total minimum sectional area ΣS and the I ² t value are considered to be proportional to the conventional common sense, and the I ² t value is narrow. The applicant conducted the following experiment that the inverse ratio (P _A / P _B ) of the number ratio (P _B / P _A ) before and after the increase of the part P is squared ((P _A / P _B ) ² ). Because it was found by.

この実験は、図４（ａ），（ｂ），（ｃ）に示すエッチング・ヒューズエレメント３１，３２，３３を試料として行った。これらヒューズエレメント３１，３２，３３は、セラミック基板３４の表面に導電性薄膜３５，３６，３７が形成されて構成されている。各導電性薄膜３５，３６，３７は、幅８[ｍｍ]，長さ４０[ｍｍ]の長方形状で、厚さｔが６０[μ]で均一の銅箔からなり、同図（ｄ）に拡大して示す直径φで間隔がｂの４個の円部４０、およびこの両側の半円部４１にある銅箔がエッチングによって除去され、それぞれ図示するようにパターンニングされている。 This experiment was performed using the etching fuse elements 31, 32, and 33 shown in FIGS. 4A, 4B, and 4C as samples. These fuse elements 31, 32 and 33 are configured by forming conductive thin films 35, 36 and 37 on the surface of a ceramic substrate 34. Each of the conductive thin films 35, 36, and 37 has a rectangular shape with a width of 8 [mm] and a length of 40 [mm], and is made of a uniform copper foil with a thickness t of 60 [μ], as shown in FIG. The copper foils in the four circular portions 40 with the diameter φ and the interval b shown in an enlarged manner and the semicircular portions 41 on both sides thereof are removed by etching and patterned as shown in the figure.

このパターンニングにより、同図（ａ）に示すヒューズエレメント３１の導電性薄膜３５は、断面積が狭小にされた狭小部Ｐが５個電気的に並列に配置された並列遮断部４２が、５個電気的に直列に配置されて、５Ｓ５Ｐにパターンニングされいる。また、同図（ｂ）に示すヒューズエレメント３２の導電性薄膜３６は、狭小部Ｐが５個電気的に並列に配置された並列遮断部４２が４個電気的に直列に配置されて、４Ｓ５Ｐにパターンニングされいる。また、同図（ｃ）に示すヒューズエレメント３３の導電性薄膜３７は、狭小部Ｐが５個電気的に並列に配置された並列遮断部４２が３個電気的に直列に配置されて、３Ｓ５Ｐにパターンニングされいる。 As a result of this patterning, the conductive thin film 35 of the fuse element 31 shown in FIG. 5A has five parallel blocking portions 42 in which five narrow portions P having a narrow cross-sectional area are electrically arranged in parallel. Individually arranged in series and patterned to 5S5P. Further, in the conductive thin film 36 of the fuse element 32 shown in FIG. 4B, four parallel blocking portions 42 in which five narrow portions P are electrically arranged in parallel are electrically arranged in series, and 4S5P. Is patterned. Further, in the conductive thin film 37 of the fuse element 33 shown in FIG. 6C, three parallel blocking portions 42 in which five narrow portions P are electrically arranged in parallel are electrically arranged in series, and 3S5P. Is patterned.

上記実験は、さらに、導電性薄膜３５，３６，３７の各並列遮断部４２における並列配置された狭小部Ｐの個数を４個にして、５Ｓ４Ｐ，４Ｓ４Ｐ，３Ｓ４Ｐにパターンニングした図示しないエッチング・ヒューズエレメントも試料に用いた。そして、これら各試料における狭小部Ｐの幅ｂの値を０．０９，０．１，０．１１，０．１２[ｍｍ]とし、図６の表に示す、Ａ，Ｂ，Ｃ，Ｄ，Ｅ，Ｆ，Ｇ，Ｈ，Ｉ，Ｊ，Ｋ，Ｌの１２種類の試料を各３枚、計３６枚製作した。ここで、ヒューズ筒の大きさは、定格電圧の値と小型化の目標によって決められているので、定格電流を決めるものは、ヒューズ筒内で発生する熱量であり、その主たるものは遮断点の発熱であるから、各試料は、形状係数Ｋ（Ｋ＝（φ／ｂ）×（Ｓ／Ｐ）×（１／１００））の値が全て同一の値（１．００）となるように製作している。 In the above experiment, the number of the narrow portions P arranged in parallel in each of the parallel blocking portions 42 of the conductive thin films 35, 36, and 37 is set to 4 and etched fuses (not shown) patterned to 5S4P, 4S4P, and 3S4P. The element was also used for the sample. The values of the width b of the narrow portion P in these samples are 0.09, 0.1, 0.11, 0.12 [mm], and A, B, C, D, A total of 36 samples of 3 types each of 12 types of samples E, F, G, H, I, J, K, and L were produced. Here, the size of the fuse cylinder is determined by the value of the rated voltage and the goal of miniaturization, so what determines the rated current is the amount of heat generated in the fuse cylinder, and the main one is the breaking point. Because of the heat generation, each sample is manufactured so that the shape factor K (K = (φ / b) × (S / P) × (1/100)) has the same value (1.00). is doing.

実験は、これら試料を、図５に示す等価ＬＣ遮断試験回路で遮断試験をすることにより、行った。この遮断試験回路は、５[ｋＶ]に充電された１４，０００[μＦ]のコンデンサＣ_１と空芯リアクトルＬ_０とによって商用周波数５０[Ｈｚ]の共振電流を発生させ、この共振電流を事故電流として被試験器Ｆとされる各試料に流す。コンデンサＣ_１への充電は、ＡＣ２００[Ｖ]までの可変電圧が印加される６[ｋＶ]のトランスＴｒで行われ、スイッチＳ_１，Ｓ_２を投入することにより、被試験器Ｆに共振電流が流される。また、空芯リアクトルＬ_０の接続を変えることにより、被試験器Ｆにかかる電圧が調整され、また、タップＴａ，Ｔｂ間に挿入されるリアクトルＬ１〜Ｌ３の種類により、回路定数が変更される。遮断試験電流Ｉａはシャント抵抗ｓｈを介して計測され、遮断試験電圧Ｖａは抵抗ＶＤを介して計測される。 The experiment was performed by conducting a block test on these samples using the equivalent LC block test circuit shown in FIG. This interruption test circuit generates a resonance current with a commercial frequency of 50 [Hz] by a 14,000 [μF] capacitor C ₁ and an air-core reactor L ₀ charged to 5 [kV], and this resonance current is accidentally caused. A current is passed through each sample as the device under test F. The capacitor C ₁ is charged by a 6 [kV] transformer Tr to which a variable voltage up to AC 200 [V] is applied, and the resonance current is supplied to the device under test F by turning on the switches S ₁ and S _2. Will be washed away. Further, the voltage applied to the device under test F is adjusted by changing the connection of the air-core reactor L ₀ , and the circuit constant is changed depending on the types of the reactors L ₁ to L ₃ inserted between the taps Ta and Tb. . The interruption test current Ia is measured via the shunt resistor sh, and the interruption test voltage Va is measured via the resistor VD.

図６に示す実験結果Ｉｍ[Ａ]，実験結果Ｉ^２ｔ[Ａ^２Ｓ]の欄の各値は、各試料についての３回の遮断試験で得られた遮断電流のピーク電流値Ｉｍ，およびＩ^２ｔ値の各平均値である。 Each value in the column of the experimental result Im [A] and the experimental result I ² t [A ² S] shown in FIG. 6 is the peak current value Im of the breaking current obtained in the three breaking tests for each sample, and Each average value of I ² t values.

図７は、図６に示す試料Ｄを被試験器Ｆとして上記の回路で遮断試験を行った実験結果を、各試料の代表として示している。同図（ａ）は縦軸を電圧[Ｖ]，横軸を時間[ｍｓｅｃ]とする試料Ｄの遮断電圧波形のグラフ、同図（ｂ）は縦軸を電流[Ａ]，横軸を時間[ｍｓｅｃ]とする試料Ｄの遮断電流波形のグラフである。 FIG. 7 shows, as a representative of each sample, an experimental result in which the interruption test was performed in the above circuit using the sample D shown in FIG. FIG. 4A is a graph of the cut-off voltage waveform of the sample D with the vertical axis representing voltage [V] and the horizontal axis representing time [msec]. FIG. 5B shows the vertical axis representing current [A] and the horizontal axis representing time. It is a graph of the interruption current waveform of sample D made into [msec].

図８は、縦軸にとった図６に示した実験結果Ｉ^２ｔ値を、横軸にとった円部４０の直径φと対比して示したグラフである。このグラフでは、Ｉ^２ｔ値を５Ｓ型、４Ｓ型、３Ｓ型にグループ化した。このグラフから、Ｉ^２ｔ値は、５Ｓ＜４Ｓ＜３Ｓの順に大きくなっていることが分かる。さらに、各グループ内の各試料のＩ^２ｔ値の違いを見ると、例えば、試料Ａと試料Ｇとでは、φの値はほぼ同一であるのにＩ^２ｔ値に差が出ている。これは、ｂ値とＰ値の違いによって生じたものと考えられ、狭小部Ｐの幅ｂの値が大きく、並列個数Ｐが少ないほど、Ｉ^２ｔ値が大きくなると言える。他の各試料についても調べた結果、これと同じことが言える。 FIG. 8 is a graph showing the experimental result I ² t value shown in FIG. 6 taken on the vertical axis in comparison with the diameter φ of the circular portion 40 taken on the horizontal axis. In this graph, the I ² t values are grouped into 5S type, 4S type, and 3S type. From this graph, it can be seen that the I ² t value increases in the order of 5S <4S <3S. Further, looking at the difference in the I ² t value of each sample in each group, for example, the sample A and the sample G have the same φ value, but a difference in the I ² t value. This is considered to be caused by the difference between the b value and the P value, and it can be said that the I ² t value increases as the width b of the narrow portion P increases and the parallel number P decreases. As a result of examining other samples, the same can be said.

図９は、縦軸にとった図６に示した実験結果Ｉｍ値を、横軸にとった円部４０の直径φと対比して示したグラフである。このグラフを用いて、Ｉ^２ｔ値に最も大きく影響を与えるＩｍの特性について検討すると、各試料についてのプロットは極めて規則的な関係があることが分かった。さらに詳しく調べて見ると、プロットＡ，Ｂを含む５Ｐの特性線５１とプロットＧ，Ｈ，Ｉを含む４Ｐの特性線５２との間で、総合最小断面積ΣＳ（＝ｂ×ｔ×Ｐ）は、５Ｐで２７０００×１０^−１２（＝９０[μ]×６０[μ]×５）、４Ｐで２６４００×１０^−１２（＝１１０[μ]×６０[μ]×４）となっているので、その差は僅かに２％である。同様に、プロットＤ，Ｅ，Ｆを含む５Ｐの特性線５３とプロットＪ，Ｋ，Ｌを含む４Ｐの特性線５４との間で、総合最小断面積ΣＳは、５Ｐで３００００×１０^−１２（＝１００[μ]×６０[μ]×５）、４Ｐで２８８００×１０^−１２（＝１２０[μ]×６０[μ]×４）となっているので、その差は僅かに４％である。従って、その差は無いものと考えると、同一φ値に対するＩｍ値は、狭小部Ｐの増加前後の個数比に逆比例していることが明白となった。 FIG. 9 is a graph showing the experimental result Im value shown in FIG. 6 taken on the vertical axis in comparison with the diameter φ of the circular portion 40 taken on the horizontal axis. Using this graph, the characteristics of Im that have the greatest influence on the I ² t value were examined, and it was found that the plots for each sample had a very regular relationship. When examined in more detail, the total minimum sectional area ΣS (= b × t × P) between the 5P characteristic line 51 including the plots A and B and the 4P characteristic line 52 including the plots G, H, and I Is 27000 × 10 ⁻¹² (= 90 [μ] × 60 [μ] × 5) at 5P, and 26400 × 10 ⁻¹² (= 110 [μ] × 60 [μ] × 4) at 4P The difference is only 2%. Similarly, between the 5P characteristic line 53 including the plots D, E, and F and the 4P characteristic line 54 including the plots J, K, and L, the total minimum cross-sectional area ΣS is 30000 × 10 ⁻¹² (5P). = 100 [μ] × 60 [μ] × 5) 4P is 28800 × 10 ⁻¹² (= 120 [μ] × 60 [μ] × 4), so the difference is only 4% . Therefore, when it is considered that there is no difference, it has become clear that the Im value for the same φ value is inversely proportional to the number ratio before and after the increase in the narrow portion P.

例えば、特性線５１と特性線５２との間で、同一φ値に対するＩｍ値は、例えば、φ＝０．９のところで特性線５１が１３２０、特性線５２が１６８０になっているので、特性線５２の１６８０は、特性線５１の１３２０に対して約１．２７倍になり、狭小部Ｐの増加前後の個数比（４／５）のほぼ逆比（５／４＝１．２５）倍になっている。また、特性線５３と特性線５４との間で、同一φ値に対するＩｍ値は、例えば、φ＝１．０のところで特性線５３が１５９５、特性線５４が１９８０になっているので、特性線５４の１９８０は、特性線５３の１５９５に対して約１．２４倍になり、狭小部Ｐの増加前後の個数比（４／５）のほぼ逆比（５／４＝１．２５）倍になっている。 For example, the Im value for the same φ value between the characteristic line 51 and the characteristic line 52 is, for example, the characteristic line 51 is 1320 and the characteristic line 52 is 1680 when φ = 0.9. 1680 of 52 is about 1.27 times as large as 1320 of the characteristic line 51, and is almost the inverse ratio (5/4 = 1.25) times the number ratio (4/5) before and after the increase of the narrow portion P. It has become. Also, the Im value for the same φ value between the characteristic line 53 and the characteristic line 54 is, for example, 1595 for the characteristic line 53 and 1980 for the characteristic line 54 when φ = 1.0. 1980 of 54 is about 1.24 times as large as 1595 of the characteristic line 53, and is almost the inverse ratio (5/4 = 1.25) times the number ratio (4/5) before and after the increase of the narrow portion P. It has become.

すなわち、このグラフから、Ｉｍ値は、狭小部Ｐの増加前後の個数比（Ｐ_Ｂ／Ｐ_Ａ）の逆比（Ｐ_Ａ／Ｐ_Ｂ）倍になることが言える。従って、Ｉｍ値の二乗に比例するＩ^２ｔ値は、前述したように、狭小部Ｐの増加前後の個数比（Ｐ_Ｂ／Ｐ_Ａ）の逆比（Ｐ_Ａ／Ｐ_Ｂ）の二乗（（Ｐ_Ａ／Ｐ_Ｂ）^２）倍になるということが分かり、大きな成果を得ることが出来た。 That is, from this graph, it can be said that the Im value is an inverse ratio (P _A / P _B ) times the number ratio (P _B / P _A ) before and after the increase of the narrow portion P. Accordingly, the I ² t value proportional to the square of the Im value is, as described above, the square of the inverse ratio (P _A / P _B ) of the number ratio (P _B / P _A ) before and after the increase of the narrow portion P (( It was found that P _A / P _B ) ² ) times, and great results were obtained.

図１０は、縦軸にとった図６の表に示した補正Ｉ^２ｔ[Ａ^２Ｓ]を、横軸にとった円部４０の直径φと対比して示したグラフである。補正Ｉ^２ｔ値は、Ｉ^２ｔ値を１／Ｐ^２で補正した値である。このグラフから、各プロットはある線上に並び、Ｄ→Ｆで示される下限特性と、Ｇ→Ｃで示される上限特性とがあることが分かる。これは、３Ｓ型、４Ｓ型がアーク電圧が上昇せず、不安定遮断のためと言うことが出来る。３Ｓ、４Ｓ型は、定格電圧６００[Ｖ]用のヒューズリンクとしては不適格であり、５Ｓ型が適格と考えられる。また、このグラフから、φ＝０．９５[ｍｍ]付近にＩ^２ｔ値の最小値があり、その値は２７０[Ａ^２Ｓ]であることが分かる。 FIG. 10 is a graph showing the correction I ² t [A ² S] shown in the table of FIG. 6 on the vertical axis in comparison with the diameter φ of the circular portion 40 on the horizontal axis. The corrected I ² t value is a value obtained by correcting the I ² t value by 1 / P ² . From this graph, it can be seen that the plots are arranged on a certain line and have a lower limit characteristic indicated by D → F and an upper limit characteristic indicated by G → C. This can be said that the 3S type and 4S type do not increase the arc voltage and are because of unstable interruption. The 3S and 4S types are not suitable as a fuse link for a rated voltage of 600 [V], and the 5S type is considered suitable. Further, it can be seen from this graph that there is a minimum value of I ² t value in the vicinity of φ = 0.95 [mm], and the value is 270 [A ² S].

上記の実験の結果から、最もよい特性が得られる試料の導電性薄膜のエッチングパターンは、５Ｓ直列型で、φ＝０．９５[ｍｍ]のものであり、狭小部Ｐの幅ｂはエッチングの精度が許す限り細くし、並列個数は定格電流によって決定すればよいことが分かった。Ｉ^２ｔ値は、５Ｓ５Ｐでφ＝０．９５[ｍｍ]とすれば２７０[Ａ^２Ｓ]になるという結果が得られており、この値は現用の同定格ヒューズのＩ^２ｔ値である５６０[Ａ^２Ｓ]に対して５０％以下に抑えられることが分かった。 From the result of the above experiment, the etching pattern of the conductive thin film of the sample that can obtain the best characteristics is 5S series type, φ = 0.95 [mm], and the width b of the narrow portion P is determined by the etching. It was found that the precision should be as thin as possible, and the number of parallels should be determined by the rated current. The I ² t value is 270 [A ² S] when φ = 0.95 [mm] at 5S5P. This value is the I ² t value of the current rated fuse. It was found that it was suppressed to 50% or less with respect to 560 [A ² S].

なお、図３に示した本実施形態によるヒューズエレメント２１では、導電性薄膜２３が、並列遮断部２３ｃの厚さが並列遮断部以外の厚さに比較して薄く形成され、この薄くされた分に基づいて狭小部Ｐの個数が薄くしない場合に比べてさらに多く形成されている場合について説明した。しかし、導電性薄膜２３は、エッチング技術の将来の向上によって狭小部Ｐの断面積がより小さく形成され、この断面積が小さくされた分に基づいて狭小部Ｐの個数が多く形成されていればよく、また、狭小部Ｐ間のピッチが各狭小部Ｐの冷却特性の独立性を失わないところまで狭く形成され、この狭くされた分に基づいて狭小部Ｐの個数が多く形成されていてもよい。この構成によっても、Ｉ^２ｔ値を小さくしながら総合最小断面積ΣＳを同等または同等以上に設定することが出来るヒューズエレメントが提供される。ただし、狭小部Ｐの個数は、並列遮断部２３ｃの厚さが並列遮断部以外の厚さに比較して薄く形成される上記実施形態の場合の方が、狭小部Ｐの断面積をより容易に縮小させることが出来るため、狭小部Ｐ間のピッチが狭く形成される場合よりもさらに多く形成することが出来る。 In the fuse element 21 according to the present embodiment shown in FIG. 3, the conductive thin film 23 is formed such that the thickness of the parallel blocking portion 23c is smaller than the thickness other than the parallel blocking portion. The case where the number of the narrow portions P is formed more than the case where the number of the narrow portions P is not made thin has been described. However, if the conductive thin film 23 is formed with a smaller cross-sectional area of the narrow portion P due to future improvements in etching technology, and the number of the narrow portions P is increased based on the reduced cross-sectional area. In addition, even if the pitch between the narrow portions P is narrow so that the independence of the cooling characteristics of each narrow portion P is not lost, and the number of the narrow portions P is increased based on the narrowed portion. Good. This configuration also provides a fuse element that can set the total minimum cross-sectional area ΣS to be equal or equal to or greater while reducing the I ² t value. However, the number of the narrow portions P is more easily reduced in the cross-sectional area of the narrow portion P in the case of the above embodiment in which the thickness of the parallel blocking portion 23c is formed thinner than the thickness other than the parallel blocking portion. Therefore, it can be formed more than the case where the pitch between the narrow portions P is narrow.

本実施形態によるヒューズエレメント２１は、電力用限流ヒューズ、特に半導体保護用ヒューズに適用すると、好適である。 The fuse element 21 according to the present embodiment is suitable when applied to a current limiting fuse for power, particularly a semiconductor protection fuse.

従来のヒューズエレメントの平面図である。It is a top view of the conventional fuse element. 従来のヒューズエレメントの遮断波形を示すグラフである。It is a graph which shows the interruption | blocking waveform of the conventional fuse element. 本発明の一実施形態によるヒューズエレメントの平面図である。1 is a plan view of a fuse element according to an embodiment of the present invention. 本発明の一実施形態によるヒューズエレメントを製作する上で行った実験試料の平面図である。It is a top view of the experimental sample performed when manufacturing the fuse element by one Embodiment of this invention. 上記実験に用いられた遮断試験回路図である。It is the interruption | blocking test circuit diagram used for the said experiment. 上記実験に用いられた各試料と実験結果とを示す表図である。It is a table | surface figure which shows each sample used for the said experiment, and an experimental result. 上記実験における代表的な遮断波形を示すグラフである。It is a graph which shows the typical interruption | blocking waveform in the said experiment. 上記実験により得られたＩ^２ｔ値とφ値との関係を示すグラフである。It is a graph showing the relationship between the I ^{2 t} value and φ values obtained by the above experiment. 上記実験により得られたＩｍ値とφ値との関係を示すグラフである。It is a graph which shows the relationship between Im value obtained by the said experiment, and (phi) value. 上記実験により得られた補正Ｉ^２ｔ値とφ値との関係を示すグラフである。Is a graph showing the relationship between the correction I ^{2 t} value and φ values obtained by the above experiment.

Explanation of symbols

２１…ヒューズエレメント
２２…セラミック基板
２３…導電性薄膜
２３ａ…円部
２３ｂ…半円部
２３ｃ…並列遮断部
Ｐ…狭小部
DESCRIPTION OF SYMBOLS 21 ... Fuse element 22 ... Ceramic substrate 23 ... Conductive thin film 23a ... Circle part 23b ... Semicircle part 23c ... Parallel interruption | blocking part P ... Narrow part

Claims

A conductive thin film formed on the surface of a substrate having an electrically insulating substrate and a parallel blocking portion in which narrow portions having a narrow cross-sectional area are electrically arranged in parallel are further arranged in series. In the fuse element composed of
The conductive thin film is formed such that the cross-sectional area of the narrow portion is small, the number of the narrow portions is formed based on the reduced cross-sectional area, and the total minimum cross-sectional area of the narrow portion is A fuse element characterized in that the fuse element is set to a product of a cross-sectional area of the narrow portion with a value inversely proportional to a number ratio before and after the increase of the narrow portion as a minimum value and a number after the increase of the narrow portion.

The conductive thin film is formed so narrow that the pitch between the narrow portions does not lose the independence of the cooling characteristics of the narrow portions, and the number of the narrow portions is formed based on the narrowed portion. The fuse element according to claim 1, wherein the fuse element is provided.

The conductive thin film is formed such that the thickness of the parallel blocking portion is smaller than the thickness other than the parallel blocking portion, and the number of the narrow portions is formed based on the thinned portion. The fuse element according to claim 1 or 2, characterized by the above-mentioned.