Patent ID: 8138655
Filing Date: 2012-03-20
Classification: H01G,H02N

Abstract:
1. An electrostatic actuator comprising: a substrate; a first lower electrode and a second lower electrode formed apart from each other above the substrate; an electrode portion formed above the first lower electrode and the second lower electrode to have a cavity portion, including a first upper electrode, a second upper electrode, and a third upper electrode formed between the first upper electrode and the second upper electrode, the first upper electrode opposing the first lower electrode and having a first portion and a second portion, a first distance between the first upper electrode and the first lower electrode at the first portion being greater than a second distance between the first upper electrode and the first lower electrode at the second portion, the second upper electrode opposing the second lower electrode and having a third portion and a fourth portion, a third distance between the second upper electrode and the second lower electrode at the third portion being greater than a fourth distance between the second upper electrode and the second lower electrode at the fourth portion, a first boundary portion between the first upper electrode and the third upper electrode having a convex shape, a second boundary portion between the second upper electrode and the third upper electrode having a convex shape, and the electrode portion driving the third upper electrode by applying a potential difference between the first lower electrode and the first upper electrode and between the second lower electrode and the second upper electrode; a first layer and a second layer formed in the first boundary portion and the second boundary portion, respectively; and a third lower electrode formed above the substrate to oppose the third upper electrode, and wherein a lower surface and an upper surface of the first upper electrode is exposed in a portion other than the first boundary portion, and a lower surface and an upper surface of the second upper electrode is exposed in a portion other than the second boundary portion, before the third upper electrode is driven, a fifth distance between the third upper electrode and the third lower electrode is equal to a sixth distance and a seventh distance, the sixth distance is a distance between the first upper electrode and the first lower electrode in a first end portion of the first upper electrode adjacent to the third upper electrode, and the seventh distance is a distance between the second upper electrode and the second lower electrode in a third end portion of the second upper electrode adjacent to the third upper electrode.