Method of making an electronic device

Abstract

An electronic device containing an electronic element such as a thermistor element is produced first by providing the element with electrodes formed on its two main surfaces facing outward away from each other, at least two terminals and a casing. Each terminal has a contact part for contacting one of the electrodes and an extended part extending from the contact part. The contact part of at least one of the terminals is elastic and bendable. The terminals and the electronic element are inserted into the casing either sequentially or simultaneously as an assembly in any of the ways such that the electrodes on the electronic element are not rubbed directly against the contact parts of the terminals. This may be done by disposing flexible guide plates over the contact parts such that the electrodes will glide over these guide plates as the electronic element is inserted after the terminals are installed inside the casing. Alternatively, the contact parts may be contacted to the electrodes to form an assembly outside the casing which is made divisible into two parts, and the assembly is placed into one of the divided parts and the two parts of the casing are joined together.

What is claimed is:  
     
         1 . A method of making an electronic device, said method comprising the steps of: 
 providing an electronic element having two main surfaces which face outward away from each other and electrodes formed individually on said main surfaces;    providing at least two terminals each having a contact part for contacting one of said electrodes and an extended part extending from said contact part, the contact part of at least one of said terminals being an elastic contact part for elastically contacting a corresponding one of said electrodes;    providing a casing for containing therein said electronic element and the contact parts while said electronic element is sandwiched between said terminals with each of said contact parts contacting the corresponding electrode and the extended parts extending out of said casing;    inserting said electronic element into said casing; and    inserting said terminals into said casing, wherein said steps of inserting said electronic element and said terminals are carried out without having either of said electrodes rubbed by said elastic contact part.    
     
     
         2 . The method of    claim 1    wherein each of said electrodes has a first layer and a second layer which is formed on said first layer with an peripheral part of said first layer exposed, and wherein the steps of inserting said electronic element and said terminals are carried out without having said exposed peripheral part of said first layer rubbed by said elastic contact part.  
     
     
         3 . The method of    claim 2    wherein said first layer is made of a first metal and said second layer is made of a second metal, said first metal being less likely to generate migration than said second metal.  
     
     
         4 . The method of    claim 3    wherein said electronic element is a heat-generating element which generates heat when in operation.  
     
     
         5 . The method of    claim 4    wherein said heat-generating element is a thermistor element.  
     
     
         6 . The method of    claim 1    wherein the step of inserting said electronic element is carried out after the step of inserting said terminals and comprises the steps of: 
 disposing a flexible planar guide plate between said elastic contact part inside said casing and the corresponding electrode of said electronic element before said electronic element is inserted into said casing;  
 inserting said electronic element into said casing until said electrodes reach positions each facing a corresponding one of the contact parts; and  
 thereafter pulling out said guide plate.  
 
     
     
         7 . The method of    claim 1    wherein the steps of inserting said electronic element and said terminals include the steps of: 
 setting said electronic element and said terminals in an assembled condition by causing each of said electrodes to be contacted by a corresponding one of the contact parts of said terminals, said terminals having a gap therebetween; and  
 thereafter inserting said electronic element and said terminals into said casing together while maintaining said electronic element and the corresponding contact parts in said assembled condition and elastically deforming said elastic contact part so as to narrow said gap between said terminals.  
 
     
     
         8 . The method of    claim 7    wherein said casing includes a main part and a lid, said main part having at least one open surface and serving to surround said electronic element and the contact parts, said lid having throughholes, serving to allow the extended parts of said terminals to pass therethrough and to support said electronic element and said terminals, and being engageable to said main part to thereby close said open surface of said main part; 
 wherein the step of setting said electronic element and said terminals in said assembled condition includes the steps, while said terminals are supported by said lid, of: 
 increasing a distance of separation between the contact parts;  
 thereafter positioning said electronic element between said contact parts; and  
 thereafter decreasing said distance of separation between said contact parts;  
 
 and wherein the steps of inserting said electronic element and said terminals are carried out while said terminals are supported by said lid and include the step of attaching said lid to said main part.  
 
     
     
         9 . The method of    claim 8    wherein at least one of said throughholes has a clearance which is sufficiently large to allow one of said terminals passing therethrough and being supported by said lid to vary the angle of the one terminal passing therethrough with respect to said lid; and 
 wherein the step of increasing said distance of separation between said contact parts includes varying said angle of said one terminal inside said clearance.  
 
     
     
         10 . The method of    claim 9    wherein the one throughhole having said clearance has a sloped inner wall for allowing said angle of said inserted one terminal to be varied more than if said clearance had not said sloped inner wall.  
     
     
         11 . The method of    claim 1    wherein said casing is divisible into a first half and a second half across a dividing plane which is parallel to said main surfaces of said electronic element; and 
 wherein the steps of inserting said electronic elements and said terminals into said casing include the steps of: 
 disposing said electronic element and one of said two terminals inside said first half such that the contact part of said one terminal is in contact with one of said electrodes of said electronic element;  
 thereafter disposing the other of said two terminals such that the contact part of said other terminal contacts the other of said electrodes; and  
 thereafter joining said first half and said second half to form said casing.  
 
 
     
     
         12 . The method of    claim 11    wherein the step of disposing the other terminal is carried out while said second half supports said other terminal.