Patent ID: 8288917
Filing Date: 2012-10-16
Classification: H01G,H02N

Abstract:
1. An electret electrode, comprising: a plurality of conductive films spaced apart from each other; a plurality of silicon oxide films retaining an electric charge and being disposed above the plurality of conductive films; and an insulating film disposed between the plurality of conductive films and the plurality of silicon oxide films, the insulating film including a laminate having a first insulating film and a second insulating film so that the first insulating film is disposed on a proximal side of the plurality of conductive films, wherein the plurality of conductive films is disposed such that the conductive films are only below a region where the plurality of silicon oxide films retaining an electric charge is disposed, and wherein the plurality of conductive films is surrounded by the first insulating film and the width of the plurality of conductive films is shorter than that of the first insulating film.