Tetsuhiko Iizuka

Precise positioning of a micro conveyor based on superconducting magnetic levitation

The design and the driving characteristics of a micro conveyor based on superconducting magnetic levitation are reported. This actuator consists of three parts; a superconductor (Y-Ba-Cu-O), a stator layer made by patterned copper electrodes (line pitch: 180 /spl mu/m, width: 70 /spl mu/m) on the polyimide film and a slider with four permanent magnets (the size of one magnet is 1 mm cube). This conveyance actuator is free from particle generation, because there is no friction by the magnetic levitation. The position of the slider is controlled by the current in the patterned electrodes. We have obtained quick conveyance (280 /spl mu/m/s over 2.8 mm) and precise positioning with an accuracy of 40 /spl mu/m by combining the step actuation in the entire area and the micro-step actuation in the local area near the target position.

Copper microcoil arrays for the actuation of optical matrix microswitches

Copper micro-coil arrays have been designed and realized by electroplating for the actuation of arrays of optical matrix micro-switches. The good operation of the micro-switches needs large force that is well fulfilled by the electromagnetic actuation of copper micro-coils. The electromagnetic behavior of the actuator has been examined using the simulator FLUX2DTM and an optimized configuration of ferromagnetic materials was determined. Arrays of micro-coils with high aspect ratio have been achieved with the use of SU8 resin mould. The diameters of micro-coils range from 0.5 millimeters to 4 millimeters with thickness of about 30 micrometers and few tens of turns. Electric measurements have been done in order to characterize the micro-coils.

Electrostatic micro actuators with high-aspect-ratio driving gap for hard disk drive application

Micro actuators are developed for hard disk drive application. The aim is high density data storage by positioning the read and write head element precisely. The desired specifications are displacement of /spl plusmn/1 /spl mu/m, operating voltage of 20 V and structural resonance frequency of 151 Hz. We fabricated a metallic actuator by using thick photoresist lithography and nickel electroplating. The electrostatic gap between the mover and the stator has high aspect ratio to achieve low voltage operation. We introduce a vertical sacrificial layer of copper to make the electrostatic gap. We utilize photoresist with thickness of 10 /spl mu/m. We completed the process and operated the actuator successfully. We also developed a silicon actuator using silicon deep etching and deposition technology. We use ICP-RIE for silicon etching and LPCVD for deposition of the vertical sacrificial layer of SiO/sub 2/ and the mover structure of polysilicon. We obtained an actuator which had thickness of 100 /spl mu/m with electrode gap of aspect ratio of 50.

A Threaded Wobble Motor A Micro Motor Generating Large Linear Displacement

SUMMARY This paper deals with the driving principle and the experimental demonstration of, a micro motor which can convert rotation into linear motion and generate large displacement. The motor is a wobble type one; its rotor and stators have screw threads. When the rotor turns, it moves linearly in the axial direction like a screw. The range of linear motion is limited only by the length of the rotor. The threaded wobble motor can be driven either magnetically or electrostatically. We have fabricated a magnetic version having a rotor of lmm in diameter and operated it successfully.

Fabrication of electrostatic micro-actuators for a hard disk drive application

Micro-actuators are developed for a hard disk drive application. The aim is to obtain a high density of data storage by positioning the read and write head element precisely. The desired specifications are a displacement of ±0.5 μm, operating voltage of 20 V and a structural resonance frequency of 15 kHz. We manufactured the metallic actuator by using thick photoresist lithography and nickel electroplating. The electrostatic gap between the mover and the stator has a high aspect ratio, in order to achieve low voltage operation. We deposited a copper layer by electroplating as a vertical sacrificial layer. Then we removed the copper layer at last process step to make the electrostatic gap with high aspect ratio. We utilize a photoresist which has a thickness of 10 μm as the first trial. We completed the process and operated the actuator successfully. We also developed a silicon actuator using the silicon deep etching and deposition technology. We use an Inductive Coupled Plasma-Reactive Ion Etching (ICP-RIE) machine for silicon etching and a Low Pressure Chemical Vapor Deposition (LPCVD) machine for deposition of the vertical sacrificial layer of SiO2 and the mover structure of polySi. We obtained an actuator which had thickness of 100 μm with the electrode gap having a aspect ratio of 50.

Fabrication of metalic and silicon microactuators with high-aspect-ratio driving gaps

This paper deals with microactuators for the precise positioning of read/write heads in very-high-density magnetic hard disk drives. In order to satisfy required specifications, namely the displacement of /spl plusmn/0.5/spl mu/m at or below 20V and the structural resonance frequency of 15kHz the electrostatic gap, the mover and the stator must be very small (/spl sim/2/spl mu/m) and its aspect ratio must be high (/spl sim/50). We developed the vertical sacrificial layer process to realize such high-aspect-ratio gaps.