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Diverse has devised a system to allow measurements to be carried out on MEMs devices
MEMs (Micro-Electro-Mechanical Systems) is an umbrella description of a wide range of devices that are essentially mechanical, but constructed using the same technique as microprocessors.
The system that Diverse developed uses a laser doppler/interferometer system to provide the key measurement data. The data can be position, speed or the Fourier transform of the movement. Distances resolved can be from less than a nanometre to hundreds of micrometres. Amazingly, the distances can be resolved over wide bandwidths from dc to over 1MHz.
One of the most difficult aspects of such measurements is to ensure that the whole system is mechanically static, because the smallest vibration caused by say road traffic could overwhelm the signal that is to be measured. To achieve this, Diverse built the system on an anti-vibration table with particular regard to minimising cantilever and other mechanical constructions that have low modal frequencies.
Even with a good design, when resolving very small distances, even the flap of a butterfly's wing will cause disturbance. To overcome this, the instrument has high pass filters to reject the low frequency interference and accept only the high frequency MEMs signals to be tested. There is an option for dual channel operation with the instrument working in differential mode. This technique can further reduce low frequency noise by looking not only at the point of interest, but, on the second channel a static position on the same MEMs device. Subtracting the two signals returns the required data.
When the system is used to investigate pulse responses, there is a need to synchronise the MEMs movement to the position capture of the instrumentation. To accomplish this, Diverse designed MEMs drive electronics and appropriate trigger generators.
To benefit from DIVERSE experience, whether you need development of specialist instrumentation or assistance in overcoming a specific problems, all you need to do is contact us. We would welcome the opportunity to give you a short presentation of our experience and to explore possible solutions for your requirements.
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