PMA-400 Planar Motion Analyzer - Features

The PMA-400 Planar Motion Analyzer is designed for in-plane microstructure vibration and motion analysis. In-plane measurements of microscopic structures such as MEMS or MOEMS require specialized techniques. While Laser Doppler Vibrometry provides superior resolution for out-of-plane measurements, the PMA-400 features in-plane motion analysis using specialized stroboscopic video microscopy.

Features

• Video measurement of in-plane (X, Y) motion of MEMS devices and microstructures
• Frequency range 0.001 Hz up to 1 MHz
• Time-domain measurements of displacement
• Resolution better than 10 nm
• Measurement of individual structures, or arrays simultaneously with the same video frame
• Modular design that combines with MSV-400 Micro Scanning Vibrometer to MMA-400 Micro Motion Analyzer

Stroboscopic Microscopy

Video of fast moving objects will produce blur patterns based on their motion. Using stroboscopic illumination and digital imaging, motion can be sharply frozen in time to capture the objects exact position. Short light pulses synchronized with the objects motion capture the position at precise phase angles. By shifting the timing of these pulses at phase angle increments, the motion of a moving object can be sampled and reconstructed. The internal signal generator periodically excites the component with a sine or a pulse signal. A so-called pattern generator” uses a LED to generate ultra-short flashes of light (< 50 ns) synchronously with the phase position of the excitation signal. This means that a high degree of phase accuracy is attained, even with high frequency excitation. The electronic camera shutter in turn is synchronized with the excitation. It remains open until enough light at the same phase of the periodic motion has been collected. The power of the LED generally allows sufficient illumination with only a few flashes. This procedure guarantees a high degree of measurement accuracy and a visual real-time analysis in live mode.

The System

The PMA-400 Planar Motion Analyzer is a fully integrated, high performance imaging system combining drive electronics, data acquisition and motion analysis software. The system includes high-speed imager, stroboscopic illumination source, Data Management System with data acquisition, and synchronized signal generator. Both the imager and illumination can be integrated with the optics of the proven MSV Series Microscope Scanning Vibrometer. This setup can be connected to a variety of optical microscopes or probe-stations for wafer level testing. Motion analysis is performed through convenient, interactive software for measurement control. PMA offers a variety of operation modes. The Live Video Mode provides a slow motion visualization of the moving object. In the Acquisition Mode, video sequences are sampled and analyzed using proprietary measurement algorithms.

Motion data based on pixel deviations are extracted and displayed as X, Y displacement values. Sub-pixel resolution enables the measurement of vibration amplitudes with resolution better than 10 nm.

Applications

• In-plane motion measurement of MEMS devices, such as micro actuators, to determine sensitivity curves of displacement vs. voltage.
• Ring down measurements to determine actuator-settling times.
• Microstructure failure analysis and reliability testing
• Wafer-level MEMS motion testing using probe-station
• Measurement of Bode plots