Film capacitors are one kind of capacitors that have outstanding performance, which has following main characters: non-polarity, high insulation resistance, outstanding frequency response (wide frequency response), less dielectric loss. As the film capacitors have small size and large capacity, they are used widely to transform into different product series, for example, high specific power storage capacitors, anti-EMI capacitors, anti-irradiation capacitors, safety film capacitors, long service capacitors, high reliable capacitors, high pressure all film capacitors and so on.
Thin film capacitors are made from metallization films, the metallization film is formed from a plastic film vacuum deposited with a thin metal layer, the metal layer is served as electrode.
In existing technology, two or more than two metallization films and (or) a plurality of optical films are wound into a large capacitor core by winding device, after some manufacturing procedures including metal spraying, the large capacitor core is cut into laminated capacitor cores by cutter, finally the laminated capacitor cores are used to make capacitors. This kind of laminated metallization film capacitor has disadvantages: on the plane of section of the capacitor core, the insulation distance between metallization electrodes in different potentials is the thickness of the dielectric between electrodes, the thickness is from several to dozens of μm, the withstand voltage property on the plane of section is weak only relying on the coating material thereon to insulate.