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.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.