| 摘要 |
PURPOSE: To eliminate areas of low temperature by connecting a comb-like conductor group to a pair of bus lines on an electrical insulating substrate by providing a parallel stripe group of resistance material having a positive temperature coefficient(PTC), and by performing heating along the bus lines. CONSTITUTION: A group of comb-like electrodes 32 and 34 are connected to a pair of bus lines 16 and 18 on an insulating substrate 14 to form a parallel stripe group from a PTC material 40. The bus lines have electrical resistance in the longitudinal direction, and heating is carried out along the bus lines. The width of a stripe of the material 40 is changed to acquire a desired output density in a desired region. Moreover, the bus lines 16 and 18 have diminishing tapers from power terminals 20 and 22 to the free ends of the bus lines, forming a desired output distribution in the longitudinal direction. A heating part of variable size and shape is placed on a bus line network between adjoining electrode groups, and is sepalated from adjacent heating parts in a clearance space of variable size and shape. The output distribution over the entire substrate is regulated by the change in density of heating distribution groups. After a protective cover 54 has been stripped, a heating apparatus 12 is installed on a back face of a mirror 10 under the action of an adhesive layer 52 on an insulation barrier layer 50, and is used by connecting the terminals 20 and 22 to a power source to effectively prevent the mirror 10 from being blurred. |
