Jordan and Hamburg
PTC planar heater and method for adjusting the resistance of the same
 A PTC planar heater according to the present invention is produced by bonding one or a plurality of PTC ceramic sheets, each having a pair of electrodes formed on the surface thereof, to an insulator. The electrode pairs are electrically connected in parallel by lead wires. An insulating elastic layer covers the electrodes to prevent warpage, electrical leaks, and shorting. A thickness of the PTC ceramic sheets equal to or greater than 0.5 mm prevents warpage. Resistance is adjusted by cutting conductive paths in the electrodes or by connecting predetermined portions of the electrodes. Further, in a PTC planar unit according to the present invention, a PTC thermistor element having a pair of electrodes formed thereon is in direct contact with one side of an insulation substrate, and a insulation substrate is mounted to the other side thereof. 
Nippon Tungsten Co., Ltd.
H H H H H H
H05B H05B H05B H05B H01C H01C
inventional inventional additional inventional inventional inventional
Koichi Takashi Masanori Osamu
Inenaga Kaimoto Saito Nakano