ELECTRET ELECTRODE, ACTUATOR USING THE ELECTRET ELECTRODE, OSCILLATION GENERATOR, OSCILLATION GENERATION DEVICE, AND COMMUNICATION DEVICE USING THE OSCILLATION GENERATION DEVICE

摘要

Provided is an electret electrode having an improved surface charge density. A conductive film (111) is formed on a substrate (102).  On the conductive film (111), a first insulating film (112) and a second insulating film (113) are alternately layered.  After this, electret films (110a to 110d) having a lower surface, an upper surface, and side surfaces covered with a third insulating film (114) and a fourth insulating film (115) are arranged so as to constitute an electret electrode (100).  Since the first insulating film (112) and the second insulating film (113) exist between the electret films (110a to 110d) and the conductive film (111), if the same electric charge is held, the electric field intensity in the film becomes small, and if the same electric field intensity is present, the surface charge density (surface potential) can be increased.