Electret electrode, actuator using the electret electrode, oscillation generator, oscillation generation device, and communication device using the oscillation generation device

Abstract

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.

Description

technical field [0001] The present invention relates to an electret electrode, an electrostatic induction type vibration power generator using the electret electrode, an actuator, a vibration power generating device, an electric device equipped with the vibration power generating device, and a communication device equipped with the vibration power generating device. device. Background technique [0002] An electrostatic induction type vibration power generating device has been proposed as follows (for example, refer to Patent Document 1): charge is given to one electrode of a variable capacitor, the charge is induced to the opposite electrode by electrostatic induction, and the induced charge is induced due to a change in capacitance. The charge changes, and the charge change is taken out in the form of electrical energy. [0003] Figure 7 The electrostatic induction type vibration power generator described in the above-mentioned Patent Document 1 is shown. Figure 7 It is...

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Problems solved by technology

[0017] However, if the film thickness of the silicon oxide film is increased, cracks and warpage of the substrate will occur due to the internal stress of the film, so there is a limit to increasing the thickness of the silicon oxide film.

That is, there is a problem that if the electret material is a silicon oxide film, there is a limit to the increase in surface potential (and surface charge density) due to increase in film thickness.

This leads to the following problem: In the electrostatic induction type vibration power generator, when using a silicon oxide film that holds charges as an electret, the power generation efficiency is low due to the low surface potential (surface charge density)

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