Matsushita Electric Industrial Co., Ltd.

Koichi Morimoto

Takashi Ikeda

Junji Kojima

Kiyoshi Ikeuchi

Toshiyuki Iwao

Yo Hasegawa

Shizuo Furuyama

A chip PTC thermistor comprising a conductive polymer having PTC properties, a first outer electrode, a second outer electrode, one or more inner electrodes sandwiched between the conductive polymer, a first electrode electrically directly coupled with the first outer electrode, and a second electrode. The odd-numbered inner electrode among the one-or-more inner electrodes is directly coupled with the second electrode, while the even-numbered inner electrode, with the first electrode. When total number of the inner electrodes is an odd number the second outer electrode makes direct electrical contact with the first electrode, when it is an even number the second outer electrode makes direct electrical contact with the second electrode. Defining a distance from the odd-numbered inner electrode to the first electrode, or from the even-numbered inner electrode to the second electrode, as &ldquo;a&rdquo;, while a distance between the adjacent inner electrodes, or a distance between the inner electrode placed the most adjacent to the first outer electrode, or the second outer electrode, and the first outer electrode, or the second outer electrode, as &ldquo;t&rdquo;; the PTC thermistors are constituted so that a ratio a/t is within 3-6. The chip PTC thermistors in accordance with the present invention effectively prevent an overcurrent in large current circuits.

PTC chip thermistor

A temperature sensor for prevention of an overcurrent condition in circuits of electronic equipment such as personal computers. The temperature sensor including a temperature sensitive layer provided on opposing electrodes on an insulating substrate and prepared by suspending an electrically conductive powder in a mixture of a resin obtained by copolymerizing a flexible monomer, a hydrophobic monomer, and a monomer having a glycidyl radical, and a hardening agent; and an electronic equipment employing the temperature sensor.

Temperature sensor and electronic equipment using the same

A method of manufacturing a chip PTC thermistor utilizes a piece of conductive polymer having a PTC characteristic and metal foils formed by patterning and provided on the upper and the lower sides of the piece under pressure integrally into a sheet, making a hole part in the sheet, applying a protective coating serving as plating resist to upper and lower sides of the sheet, forming an electrode on the sheet by electroplating, and cutting the sheet into a chip. The protective coating is made of a material applicable at a temperature equal to or lower than the melting point of the conductive polymer. The processing temperatures at the step from the step of making a hole part in the sheet to the pre-processing step of the step of forming an electrode by electroplating on the sheet are not above the melting point of the conductive polymer.

Method of manufacturing chip PTC thermistor

The PTC thermistor chip of the present invention comprises a conductive polymer having PTC properties, a first outer electrode, a second outer layer electrode, not less than one inner electrode sandwiched between the conductive polymer, a first electrode electrically directly coupled with the first outer electrode, and a second electrode disposed electrically independently from the first electrode. When counting from one of the inner electrodes closest to the first outer layer electrode, and defining the inner layer electrode in a &ldquo;n&rdquo;th position as the &ldquo;n&rdquo;th inner electrode, the odd-numbered inner layer electrodes are directly coupled with the second electrode and the even-numbered inner layer electrodes, with the first electrode. In this PTC thermistor, the cross sections where the odd-numbered and even numbered inner electrodes are respectively in contact with the second and first electrodes are thicker than the other sections.

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Sakai, Japan

Koichi Morimoto