Electrostatic linear microactuator mechanism for focusing a CCD camera

A newly developed linear electrostatic microactuator mechanism employing a vibrating motion is described. In order to achieve a miniature charge coupled device (CCD) camera with autofocusing and zoom functions, we developed an electrostatic linear microactuator with a large movement range. In miniature CCD cameras, extremely thin electrostatic actuators are needed because the space available for the focusing mechanism is reduced. The moving part (slider) of this actuator is sandwiched between fixed electrodes (stator), is alternately attached and detached to these fixed electrodes, and actuates linearly on a macroscopic level. The fundamental feasibility of this vibrating motion mechanism was first confirmed in experiments. This actuator was then applied to the focusing mechanism of a miniature CCD camera. A microlens was fitted inside the slider and it was possible to adjust the focus by moving the slider (with microlens). The size of the prototype for the focusing mechanism is 3.6/spl times/4.6/spl times/8.0 mm, and a 2-mm movement range is achieved. The minimum driving voltage is 60 V and the maximum velocity is 1.0 min/s.