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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.

In this paper we describe a new design of a fluid-driven microactuator which comprises a planar piston, a four-way control valve, and a mechanical feedback system that controls the output in accordance with an input displacement. Merits of this design are expected in terms of output density, scalability, and feedback ability realized with no electronic devices. Fabrication processes of the microactuator include bulk micromachining of two sheets of silicon substrate and their assembly by electro static bonding to glass plates. The output characteristics were measured while compressed air was supplied. Generated output force showed an almost linear relation ship to supplied pressure and to valve displacement. However, the magnitude was asymmetric in terms of driven directions, which resulted from geometrical configuration essentially introduced by an anisotropic etching of the silicon substrate The position of the output shaft was sufficiently controlled with a designec magnification factor multiplied to the input displacement in both static and dynamic senses.

A newly developed linear electrostatic micro actuator mechanism employing a vibrating motion is described. Features of this mechanism are that anti-friction bearings are not required, the influence of friction is reduced significantly, and a large stroke is achieved. 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. Several difficulties have been identified regarding actuators operated by attachmen/ detachment. The interactive forces, including the accumulation of charge caused by contact between each slider and stator, create one of the most difficult 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 employed. The first prototype, casing size ...

Ba2Ti9O20 with GeO2 and B2O3 was synthesized by an ordinary sintering method. Fired densities, dielectric constants and dielectric losses were measured. Ba2Ti9O20 containing B2O3 sintered at lower temperatures and Ba2Ti9O20 containing GeO2 showed more excellent dielectric properties than a single phase of Ba2Ti9O20. However, Ba2Ti9O20 containing GeO2 and B2O3 showed no improvement in the sinterability and dielectric properties by low temperature firing. A two-step addition process, i.e., separate addition of GeO2 and B2O3 before and after the calcination, respectively, was effective in reducing the firing temperature without affecting the dielectric properties. XRD (X-ray diffraction) analysis and SEM (scanning electron microscope) observation were carried out on those samples. The sintering mechanism of Ba2Ti9O20 containing GeO2 and/or B2O3 was proposed and the relationship between the microstructures and dielectric characteristics was discussed.

In this paper we describe a new design of a fluid-driven microactuator which comprises a planar piston, a four-way control valve, and a mechanical feedback system that controls the output in accordance with an input displacement. Merits of this design are expected in terms of output density, scalability, and feedback ability realized with no electronic devices. Fabrication processes of the microactuator include bulk micromachining of two sheets of silicon substrate and their assembly by electro static bonding to glass plates. The output characteristics were measured while compressed air was supplied. Generated output force showed an almost linear relation ship to supplied pressure and to valve displacement. However, the magnitude was asymmetric in terms of driven directions, which resulted from geometrical configuration essentially introduced by an anisotropic etching of the silicon substrate The position of the output shaft was sufficiently controlled with a designec magnification factor multiplied to the input displacement in both static and dynamic senses.

This paper describes a new design of a fluid driven micro-actuator which can be fabricated by anisotropic etching of single crystalline silicon. The actuator has a four-way valve to regulate the work fluid and a differential piston to generate linear force. First, fundamental flow characteristics are analyzed theoretically when the fluid flows in simple channels which have rectangular and trapezoidal cross section. Applicability of the Navier-Stokes equation assumed in the analysis is confirmed about the specific dimensions used in the actuator design by actual flow measurement. Then proposed actuator is examined separately on four constituent parts by numerical resolution of the N. S. equation. Consequently the results are integrated to estimate the output of the actuator. The design parameters of piston-casing clearance, piston width and casing height are investigated to evaluate the effect on the output. Finally the output characteristics are compared with that of an electrostatic actuator. The output and the one for unit area are expected to be a hundred times and ten times as large as those of the electrostatic actuator respectively.

Newly developed linear electrostatic micro actuators employing a vibrating motion and fabricated by a bulk silicon micromachining process are described. The moving part (slider) of these actuators is sandwiched between two glass plates whose surfaces have many electrodes (fixed electrodes), is attached and detached to these fixed electrodes by turns, and actuates linearly on a macroscopic level. A feature of these actuators is that the influence of friction is reduced significantly and a large stroke is achieved. However, several difficulties have been identified regarding attachment/detachment operation actuators. The interactive forces, including the accumulation of charge caused by contact between each stator and slider create one of the most difficult problems. Our developed actuators incorporate micro pyramid stoppers, which prevent the accumulation of charge and other interactive forces, on both surfaces of the moving parts. The casing size of the prototype is 8/spl times/8/spl times/1.2 mm and achieves a 2 mm range of movement. The minimum driving voltage is 60 V and maximum velocity is 2.0 mm/s. The behavior of the slider is not simple and further analysis is very important in order to improve positioning accuracy, increase output force, and decrease driving voltage. The characteristics of the actuator (Stepping Model) obtained by experiments is reported. The authors further apply these actuators to a micro pan-tilt mechanism for altering the vision angle of a micro CCD camera and experimentally confirm their practical utility.

Newly developed linear electrostatic micro actuators employing an attachment/detachment mechanism and fabricated by a bulk silicon micromachining process are described. The moving part (slider) of these actuators is sandwiched between two glass plates whose surfaces have many electrodes (fixed electrodes), is attached to these fixed electrodes by turns up and down, and is actuated in the course of the linear motion. A feature of these actuators is that anti-friction bearings are not required and the influence of friction is reduced significantly. Several difficulties have been identified regarding attachment/detachment operation actuators. The accumulation of charge caused by contact between each stator and slider is one of the most difficult problems, and it can lead to complete actuator failure. The newly developed actuators have micro pyramid stoppers which prevent the accumulation of charge on both surfaces of the moving part. When a diving voltage of about 80 [V] is applied, the slider moves successfully with a /spl plusmn/1 [mm] stroke at a speed of 1.0 mm/sec under the condition of no load. The authors further apply these actuators to a micro pan-tilt mechanism for altering the vision angle of a micro CCD camera and experimentally confirm their practical utility.