Alloy type thermal fuse and material for a thermal fuse element

Abstract

An alloy type thermal fuse of an operating temperature of 75 to 120° C. is provided in which a fuse element of a Bi—In—Sn alloy is used, excellent aging and heat cycle resistances for a long term can be ensured, and satisfactory operating characteristic can be ensured. A material for a thermal fuse element has an alloy composition in which In is 15% or larger and smaller than 37%, Sn is 5% or larger and 28% or smaller, and balance Bi, and in which, with respect to each of reference points of ternary Bi—In—Sn eutectic points of 57.5% Bi-25.2% In-17.3% Sn and 54.0% Bi-29.7% In-16.3% Sn, a range of ±2% Bi, ±1% In, and ±1% Sn is excluded.

What is claimed is:  
     
         1 . A material for a thermal fuse element wherein said material has an alloy composition in which In is 15% or larger and smaller than 37%, Sn is 5% or larger and 28% or smaller, and balance Bi, and in which, with respect to each of reference points of ternary Bi—In—Sn eutectic points of 57.5% Bi-25.2% In-17.3% Sn and 54.0% Bi-29.7% In-16.3% Sn, a range of ±2% Bi, +1% In, and ±1% Sn is excluded.  
     
     
         2 . A material for a thermal fuse element wherein 0.1 to 3.5 weight parts of one, or two or more elements selected from the group consisting of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, and Ge are added to 100 weight parts of an alloy composition of  claim 1 .  
     
     
         3 . An alloy type thermal fuse wherein a material for a thermal fuse element of  claim 1  is used as a fuse element.  
     
     
         4 . An alloy type thermal fuse wherein a material for a thermal fuse element of  claim 2  is used as a fuse element.  
     
     
         5 . An alloy type thermal fuse according to  claim 3 , wherein said fuse element contains inevitable impurities.  
     
     
         6 . An alloy type thermal fuse according to  claim 4 , wherein said fuse element contains inevitable impurities.  
     
     
         7 . An alloy type thermal fuse according to  claim 3 , wherein said fuse element is connected between lead conductors, and at least a portion of each of said lead conductors which is bonded to said fuse element is covered with a Sn or Ag film.  
     
     
         8 . An alloy type thermal fuse according to  claim 4 , wherein said fuse element is connected between lead conductors, and at least a portion of each of said lead conductors which is bonded to said fuse element is covered with a Sn or Ag film.  
     
     
         9 . An alloy type thermal fuse according to  claim 5 , wherein said fuse element is connected between lead conductors, and at least a portion of each of said lead conductors which is bonded to said fuse element is covered with a Sn or Ag film.  
     
     
         10 . An alloy type thermal fuse according to  claim 6 , wherein said fuse element is connected between lead conductors, and at least a portion of each of said lead conductors which is bonded to said fuse element is covered with a Sn or Ag film.  
     
     
         11 . An alloy type thermal fuse according to  claim 3 , wherein a pair of film electrodes are formed on a substrate by printing conductive paste containing metal particles and a binder, said fuse element is connected between said film electrodes, and said metal particles are made of a material selected from the group consisting of Ag, Ag-Pd, Ag-Pt, Au, Ni, and Cu.  
     
     
         12 . An alloy type thermal fuse according to  claim 4 , wherein a pair of film electrodes are formed on a substrate by printing conductive paste containing metal particles and a binder, said fuse element is connected between said film electrodes, and said metal particles are made of a material selected from the group consisting of Ag, Ag-Pd, Ag-Pt, Au, Ni, and Cu.  
     
     
         13 . An alloy type thermal fuse according to  claim 5 , wherein a pair of film electrodes are formed on a substrate by printing conductive paste containing metal particles and a binder, said fuse element is connected between said film electrodes, and said metal particles are made of a material selected from the group consisting of Ag, Ag—Pd, Ag—Pt, Au, Ni, and Cu.  
     
     
         14 . An alloy type thermal fuse according to  claim 6 , wherein a pair of film electrodes are formed on a substrate by printing conductive paste containing metal particles and a binder, said fuse element is connected between said film electrodes, and said metal particles are made of a material selected from the group consisting of Ag, Ag-Pd, Ag-Pt, Au, Ni, and Cu.  
     
     
         15 . An alloy type thermal fuse according to  claim 3 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         16 . An alloy type thermal fuse according to  claim 4 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         17 . An alloy type thermal fuse according to  claim 5 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         18 . An alloy type thermal fuse according to  claim 6 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         19 . An alloy type thermal fuse according to  claim 7 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         20 . An alloy type thermal fuse according to  claim 8 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         21 . An alloy type thermal fuse according to  claim 9 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         22 . An alloy type thermal fuse according to  claim 10 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         23 . An alloy type thermal fuse according to  claim 11 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         24 . An alloy type thermal fuse according to  claim 12 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         25 . An alloy type thermal fuse according to  claim 13 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         26 . An alloy type thermal fuse according to  claim 14 , wherein a heating element for fusing off said fuse element is additionally disposed.  
     
     
         27 . An alloy type thermal fuse according to  claim 3 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         28 . An alloy type thermal fuse according to  claim 4 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         29 . An alloy type thermal fuse according to  claim 5 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         30 . An alloy type thermal fuse according to  claim 6 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         31 . An alloy type thermal fuse according to  claim 7 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         32 . An alloy type thermal fuse according to  claim 8 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         33 . An alloy type thermal fuse according to  claim 9 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         34 . An alloy type thermal fuse according to  claim 10 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         35 . An alloy type thermal fuse according to  claim 11 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         36 . An alloy type thermal fuse according to  claim 12 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         37 . An alloy type thermal fuse according to  claim 13 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         38 . An alloy type thermal fuse according to  claim 14 , wherein said fuse element connected between a pair of lead conductors is sandwiched between insulating films.  
     
     
         39 . An alloy type thermal fuse according to  claim 3 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         40 . An alloy type thermal fuse according to  claim 4 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         41 . An alloy type thermal fuse according to  claim 5 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         42 . An alloy type thermal fuse according to  claim 6 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         43 . An alloy type thermal fuse according to  claim 7 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         44 . An alloy type thermal fuse according to  claim 8 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         45 . An alloy type thermal fuse according to  claim 9 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         46 . An alloy type thermal fuse according to  claim 10 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         47 . An alloy type thermal fuse according to  claim 11 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         48 . An alloy type thermal fuse according to  claim 12 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         49 . An alloy type thermal fuse according to  claim 13 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         50 . An alloy type thermal fuse according to  claim 14 , wherein a pair of lead conductors are partly exposed from one face of an insulating plate to another face, said fuse element is connected to said lead conductor exposed portions, and said other face of said insulating plate is covered with an insulating material.  
     
     
         51 . An alloy type thermal fuse according to  claim 3 , wherein lead conductors are bonded to ends of said fuse element, respectively, a flux is applied to said fuse element, said flux-applied fuse element is passed through a cylindrical case, gaps between ends of said cylindrical case and said lead conductors are sealingly closed, ends of said lead conductors have a disk-like shape, and ends of said fuse element are bonded to front faces of said disks.  
     
     
         52 . An alloy type thermal fuse according to  claim 4 , wherein lead conductors are bonded to ends of said fuse element, respectively, a flux is applied to said fuse element, said flux-applied fuse element is passed through a cylindrical case, gaps between ends of said cylindrical case and said lead conductors are sealingly closed, ends of said lead conductors have a disk-like shape, and ends of said fuse element are bonded to front faces of said disks.  
     
     
         53 . An alloy type thermal fuse according to  claim 5 , wherein lead conductors are bonded to ends of said fuse element, respectively, a flux is applied to said fuse element, said flux-applied fuse element is passed through a cylindrical case, gaps between ends of said cylindrical case and said lead conductors are sealingly closed, ends of said lead conductors have a disk-like shape, and ends of said fuse element are bonded to front faces of said disks.  
     
     
         54 . An alloy type thermal fuse according to  claim 6 , wherein lead conductors are bonded to ends of said fuse element, respectively, a flux is applied to said fuse element, said flux-applied fuse element is passed through a cylindrical case, gaps between ends of said cylindrical case and said lead conductors are sealingly closed, ends of said lead conductors have a disk-like shape, and ends of said fuse element are bonded to front faces of said disks.  
     
     
         55 . An alloy type thermal fuse according to  claim 7 , wherein lead conductors are bonded to ends of said fuse element, respectively, a flux is applied to said fuse element, said flux-applied fuse element is passed through a cylindrical case, gaps between ends of said cylindrical case and said lead conductors are sealingly closed, ends of said lead conductors have a disk-like shape, and ends of said fuse element are bonded to front faces of said disks.  
     
     
         56 . An alloy type thermal fuse according to  claim 8 , wherein lead conductors are bonded to ends of said fuse element, respectively, a flux is applied to said fuse element, said flux-applied fuse element is passed through a cylindrical case, gaps between ends of said cylindrical case and said lead conductors are sealingly closed, ends of said lead conductors have a disk-like shape, and ends of said fuse element are bonded to front faces of said disks.  
     
     
         57 . An alloy type thermal fuse according to  claim 9 , wherein lead conductors are bonded to ends of said fuse element, respectively, a flux is applied to said fuse element, said flux-applied fuse element is passed through a cylindrical case, gaps between ends of said cylindrical case and said lead conductors are sealingly closed, ends of said lead conductors have a disk-like shape, and ends of said fuse element are bonded to front faces of said disks.  
     
     
         58 . An alloy type thermal fuse according to  claim 10 , wherein lead conductors are bonded to ends of said fuse element, respectively, a flux is applied to said fuse element, said flux-applied fuse element is passed through a cylindrical case, gaps between ends of said cylindrical case and said lead conductors are sealingly closed, ends of said lead conductors have a disk-like shape, and ends of said fuse element are bonded to front faces of said disks.