A. Koga et al., ELECTROSTATIC LINEAR MICRO ACTUATOR WITH VIBRATING MOTION (APPLICATION TO THE FOCUSING MECHANISM OF A MINIATURE CCD CAMERA), Advanced robotics, 12(2), 1998, pp. 103-113
Citations number
9
Categorie Soggetti
Robotics & Automatic Control","Robotics & Automatic Control
A newly developed linear electrostatic micro actuator mechanism employ
ing a vibrating motion is described. Features of this mechanism are th
at anti-friction bearings are not required, the influence of friction
is reduced significantly, and a large stroke is achieved. The moving p
art (Slider) of this actuator is sandwiched between fixed electrodes (
Stator), is alternately attached and detached to these fixed electrode
s, and actuates linearly on a macroscopic level. Several difficulties
have been identified regarding actuators operated by attachmen/detachm
ent. The interactive forces, including the accumulation of charge caus
ed by contact between each slider and stator, create one of the most d
ifficult problems. Our developed actuator incorporates micro stoppers,
which prevent the accumulation of charge and other interactive forces
on the surface of the slider or the stator. A voltage supply pattern
such that the positive and negative charge appear alternately, is empl
oyed. The first prototype, casing size is 8 x 8 x 1.2 mm and range of
movement is 2.0 mm, has been fabricated by a bulk silicon micromachini
ng process and the fundamental feasibility of this vibrating motion me
chanism has been confirmed by experiments. This motion mechanism is ap
plied to a focusing mechanism of a miniature CCD camera. A micro lens
is fitted inside the slider and the focus is adjusted by moving the sl
ider (with the micro lens). The size of the prototype focusing mechani
sm is 3.6 x 4.6 x 8.0 mm and this achieves a 2 mm range of movement. T
he minimum driving voltage is 60 V and maximum velocity is 1.0 mm/s.