Matsushita Electric Industrial Co., Ltd.

Kohichi Morimoto

Takashi Ikeda

Junji Kojima

Toshiyuki Iwao

Naohiro Mikamoto

Kiyoshi Ikeuchi

Chip PTC thermistors that can easily be inspected the soldered portions after it is mounted on a printed circuit board and that can be used in a flow soldering process, and methods of making same. A chip PTC thermistor of the present invention includes: a first main electrode and a first sub-electrode on first surface of a cuboidal form conductive polymer having the PTC characteristics, a second main electrode and a second sub-electrode on a second surface opposite the first surface of the conductive polymer. Between the first sub-electrode and the second sub-electrode, and between the first sub-electrode and the second main electrode are electrically connecting with a first side electrode and a second side electrode, respectively.

Chip PTC thermistor and method for manufacturing the same

Method of manufacturing a chip PTC thermistor

A chip polymer PTC thermistor for surface mount assembly having a superior long-term connection reliability between side electrode and main and sub electrodes. The thermister comprises; a rectangular parallelepiped conductive polymer( ) having PTC properties; a first main electrode( ) and a first sub electrode( ) disposed on a first face of the conductive polymer; a second main electrode( ) and a second sub electrode( ) disposed on a second face opposite the first face of the conductive polymer; and first and second side electrodes( ) folding around and over the entire surface of side faces of the conductive polymer, the side electrodes electrically coupling the electrodes disposed on the two faces of the conductive polymer, and a thickness of the side electrodes is not less than one twentieth of the distance between the first main electrode( ) and the second sub electrode( ) and the distance between the first sub electrode( ) and second main electrode( ).

PTC thermister chip

The present invention aims to provide a PTC thermister which uses a conductive polymer having a positive temperature coefficient and has a high withstand voltage and high reliability and in which no failure in electrical connection occurs in side electrode even when a mechanical stress occurs due to the thermal shock by repeated thermal expansion of the conductive polymer sheet. It also aims to provide a method to manufacture the above PTC thermister. To achieve the above purpose, the PTC thermister of the present invention comprises (1)a laminated body made by alternately laminating conductive polymer sheets and inner electrodes, (2) outer electrodes disposed on tops and bottoms of said laminated body and (3) multi-layered side electrodes disposed at the center of both sides of said laminated body and is electrically coupled with said inner electrodes and said outer electrodes. And, a side of laminated body having an area on which a side electrode layer is formed and areas on which side electrode is not formed. A method for manufacturing a PTC thermistor comprises the steps of (1) forming a laminated body by sandwiching a conductive polymer sheet with metal foils, and then integrating them by heat pressing, (2) sandwiching the laminated body and conductive polymer sheets from the top and bottom by metal foils, and integrating them by heat pressing. A multi-layered PTC thermistor is obtained by repeating above processes.

PTC thermistor and method for manufacturing the same

The present invention aims to provide a PTC thermister which uses a conductive polymer having a positive temperature coefficient and has a high withstand voltage and high reliability and in which no failure in electrical connection occurs in side electrode even when a mechanical stress occurs due to the thermal shock by repeated thermal expansion of the conductive polymer sheet. It also aims to provide a method to manufacture the above PTC thermister. To achieve the above purpose, the PTC thermister of the present invention comprises (,) a laminated body made by alternately laminating conductive polymer sheets and inner electrodes, (,) outer electrodes disposed on tops and bottoms of said laminated body and (,) multi-layered side electrodes disposed at the center of both sides of said laminated body and is electrically coupled with said inner electrodes and said outer electrodes. And, a side of laminated body having an area on which a side electrode layer is formed and areas on which side electrode is not formed. A method for manufacturing a PTC thermistor comprises the steps of (,) forming a laminated body by sandwiching a conductive polymer sheet with metal foils, and then integrating them by heat pressing, (,) sandwiching the laminated body and conductive polymer sheets from the top and bottom by metal foils, and integrating them by heat pressing. A multi-layered PTC thermistor is obtained by repeating above processes.

Growing community of inventors

Sakai, Japan

Kohichi Morimoto