Surface-mounted thermistor and manufacturing method thereof

Abstract

A thermistor, which is to be mounted on a PCB, for protecting other circuit elements is disclosed. Electrode patterns separately formed on both surfaces of a film resistance element are respectively shaped into two parts which are engaged to each other with a non-conductive gap interposed therebetween. Thus, a Tombstone phenomenon caused by asymmetric structure may be fundamentally prevented. Grooves are formed in both sides of the thermistor, and connection portions for electrically connecting the electrodes formed on both surfaces of the thermistor are formed through the inside of the grooves or through the sides except the grooves. Thus, though a crack arises in the connection portion, it is possible to prevent the crack from being propagated to the entire connection portion along the side of the thermistor.

1 - 16 . (canceled)  
     
     
         17 . A method for manufacturing a thermistor comprising: 
 preparing a sheet configured that metal films are laminated on both surfaces of a film resistance element which changes a resistance depending on temperature;    forming a plurality of through holes having a predetermined width and a length longer than the width in the sheet in a matrix pattern;    electrically connecting the metal films laminated on both surfaces of the sheet through a side wall of the through hole;    forming an electrode pattern by patterning the metal film; and    cutting the sheet on which the electrode pattern is formed so that a region between adjacent through holes in a width direction of the through hole becomes one unit.    
     
     
         18 . A method for manufacturing a thermistor according to  claim 17 , 
 wherein, in the electrode pattern forming step, for at least one metal film formed on both surfaces of the sheet, the metal film is partially removed in each region between adjacent through holes in a width direction of the through hole so as to make the electrode pattern in two parts which are separated but symmetrically engaged to each other.    
     
     
         19 . A method for manufacturing a thermistor according to  claim 18 , wherein the metal film is removed so that a metal film-removed region has a shape of crank, rectangular wave, zigzag or wave.  
     
     
         20 . A method for manufacturing a thermistor according to  claim 17 , 
 wherein, the electrode pattern forming step, for each metal film formed on both surfaces of the sheet, the metal film is partially removed in each region between adjacent through holes in a width direction of the through hole to make the electrode pattern into two parts which are separated but engaged to each other and to make the electrode pattern coincided when the sheet is turned over.    
     
     
         21 . A method for manufacturing a thermistor according to  claim 20 , 
 wherein the metal film is removed so that a metal film-removed region has a shape of crank, rectangular wave, zigzag or wave.    
     
     
         22 . A method for manufacturing a thermistor according to  claim 17 , 
 wherein the sheet cutting step includes a step of cutting a part of the longitudinal side wall of the through hole to form a groove on the side wall.    
     
     
         23 . A method for manufacturing a thermistor according to  claim 17 , further comprising between the electrode pattern forming step and the sheet cutting step: 
 coating solder resists on both surfaces of the sheet on which the electrode pattern is formed, except a portion near the through hole; and    forming a solder on the electrode pattern exposed near the through hole where the solder resist is not coated.    
     
     
         24 . A method for manufacturing a thermistor comprising: 
 preparing a sheet configured that metal films are laminated on both surfaces of a film resistance element which changes a resistance depending on temperature;    forming a plurality of circular or oval through holes in the sheet in a matrix pattern;    electrically connecting the metal films laminated on both surfaces of the sheet through a side wall of the through hole;    forming an electrode pattern by patterning the metal films; and    cutting the sheet in which the electrode pattern is formed so that a region between adjacent through holes in one direction along the arrangement of the through holes becomes one unit,    wherein, in the electrode pattern forming step, for each metal film formed on both surfaces of the sheet, the metal film is partially removed in each region between adjacent through hoes in one direction so as to make the electrode pattern into two parts which are separated but symmetrically engaged to each other and to make the electrode pattern coincided when the sheet is turned over.    
     
     
         25 . A method for manufacturing a thermistor according to  claim 24 , 
 wherein the metal film is removed so that a metal film-removed region has a shape of crank, rectangular wave, zigzag or wave.