| 摘要 |
<p>A sheet-shaped heater is structured by attaching plural electrode covering members 4, each covering electrodes 3, on a sheet-shaped heating resistance sheet 2 to have a predetermined space from each other. At least an area adjacent to the electrode 3 is a PTC layer having positive temperature coefficient characteristics which show increasing electric resistance value with rise in temperature. The heating resistance sheet 2 does not have the positive temperature coefficient characteristics or has the positive temperature coefficient characteristics of which, in a range below the temperature showing the maximum kick-off increase ratio of the PTC layer, the kick-off increase ratio is smaller than that of the PTC layer or the kick-off temperature is higher than that of the PTC layer. <IMAGE></p> |
