Hideaki Yamagishi

Electromagnetically driven silicon microvalve for large-flow pneumatic controls

The authors report a large-flow microvalve which has an ability to replace conventional pneumatic control devices. The authors have analyzed the generating force for various driving methods and concluded a combination of silicon micromachined valve structure and electromagnetic driving is the best way for the large-flow control. The electro- magnetic actuator consists of an externally placed solenoid and a magnetic metal chip which is bonded to silicon valve chip. The actuator produces force larger than 0.1 N along 0.1 mm stroke. The valve structure is integrated on the silicon chip, which consists of an anisotropically etched orifice and a polysilicon valve sheet with springs. The polysilicon layer has a 30 micrometers thickness designed to obtain a strong structure enough to be operated with large force and large displacement. This microvalve can control large-flow gases with short response time and low power consumption, owing to electromagnetic driving. Moreover, the integration of the valve parts reduces its cost and assembly processes. The measured results show that 8.8 1/min air flow is controlled at 440 kPa by 210 mW electric power consumption and the response time is less than 3 ms, which are difficult to achieve by microvalves reported so far.

Antenna-coupled rectifying diode for IR detection

An antenna-coupled rectifying SChottky Barrier DIode (SBD) for IR detection is fabricated on Si by IC processes. Aluminum thin film antenna of 30 micrometers length and 1.5 micrometers width is formed on thermally grown SiO2 layer on Si. At the end of antenna, rectifying SBD of 0.03 micrometers diameter is formed by focused ion beam (FIB) milling technique. Ion current monitoring system with FIB largely reduced the size of milled hole, which is conventionally limited by ion beam waist diameter. IR radiation from CO2 laser of 10.6 micrometers in wavelength and 0.55 W in power is used for device evaluations. Signal dependence on incident angle of CO2 laser radiation and dependence on diode bias voltage are evaluated. We confirmed the rectifying operation of antenna- coupled SBD at IR region and experimentally obtained rectified voltage of 173 nV. The NEP is calculated to be 1.94 X 10-6 W/Hz-1/2.

An Antenna-coupled Electric Wave Detector For Microwave And Infrared Ray

Detector of an antenna-coupled electric field detection type for infrared ray is investigated. As infrared ray is one of the electromagnetic waves, so this detector receives infrared ray at an antenna, and rectifies at a nonlinear element that has high-speed response. The antenna of this device formed by lift-off process at a size of similar rank as wavelength. The rectifying device formed it as making use of a very small hole depending on FIB to be able to respond to frequency of an infrared ray. As experimental results, this detector receives microwaveselectric fields (f=50Ghz, 300mW) and converts it to the signal voltage (1.3mV). It is certified that the signal voltage is obtained through micro antenna by measuring angular dependence between antenna and polarization of microwave. From another experiments, the detector could receive C)/sub 2/laser(/spl lambda/=10.6/spl mu/m). Also, this device detected an inside electric field of a waveguide and revealed what we can use as a position sensor.