Miniaturization and performance advancement have been required for film capacito

Posted by sanny111 on June 10th, 2015

Recently, along with the miniaturization and advancement of the performance of electronic apparatus, it has been demanded for the miniaturization and advancement of performance in electronic parts, and such miniaturization and performance advancement have been required also for metallized film capacitors.

The miniaturization of the film capacitor has been performed by reducing the thickness of dielectric films in existent film capacitors. But when film capacitors are manufactured while reducing the thickness of the dielectric films, wrinkles are generated on the dielectric films, thereby making it difficult to wind broad width films having many stripes and it is difficult to manufacture miniaturized film capacitors having high performances.

For further miniaturizing film capacitors, it is necessary to reduce further the thickness of the plastic film and/or dielectric coating layer as the dielectric film.

In the plastic film, it is technically possible to reduce the film thickness to about 0.5 mu m owing to the advance of the film-forming technique, but there are various problems in the production of film capacitors using such plastic films including their handleability in the production steps.

On the other hand, in the reduction of the film thickness of the dielectric coating layer, there are problems, for example, regarding a solvent solubility, a wettability with vapor-deposited metal layer and a drying property of polycarbonate or polyphenylene oxide and it is extremely difficult for the mass production of dielectric coating layers with a uniform thin thickness of less than 1 mu m, in particular, less than 0.5 mu m. Particularly, when the film thickness of the dielectric coating layer is reduced, this brings about a drawback that pinholes occur frequently and a dielectric breakdown voltage per unit thickness lowers.

An offer of a miniature and high performance film capacitor with the film thickness of the dielectric coating layer of not more than 1 mu m has been demanded. High harmonic absorbing, high reactive power and good stability of capacitance. High-performance AC filtering capacitors used in AC-filter circuit for UPS systems, welding equipment, and tuned passive filtering.