薄膜金属ガラスを用いた微細構造物の製作 ２ 薄膜金属ガラス静電マイクロアクチュエータの提案と試作

Abstract

This paper presents a new type of electrostatic actuator (Conical Spring Linear Actuator : CSLA) capable of vertical stepwise motion to a substrate. The CSLA is made of a thin film metallic glass (TFMG) of a conical spring shape. The TFMG is expected to be a material suitable for micro structures because it is an amorphous alloy which free from anisotropy and defects originating from the crystal structure. Micro machining of TFMG is possible by a lift-off technique. Moreover TFMG softens at a certain temperature range called the supercooled liquid state, which allows surface micro-machined TFMG structures to be easily formed into three-dimensional shapes. This micro forming technique allows the conical spring shape of the CSLA. The conical spring acting as a moving electrode was assembled on a fixed four-section electrode on the substrate so that the actuator could make a stepwise motion. The CSLA showed vertical stepwise motion of four stages to the substrate by switching the electrodes, which were applied in rotation at a constant voltage (17V). The total displacement of the CSLA was limited to 30μm due to the unexpected deformation of the conical spring.