Small voice coil motor drives laser mirrors.
A new voice coil motor from Equipment Solutions of Sunnyvale, Calif., uses a flexure bearing to provide precise positioning in a very compact package. The RVC-5 was designed to tilt a mirror or grating in laser and optical systems.
Potential uses include laser marking, cutting, and welding, as well as light shows, semiconductor fabrication, optical testing, scanning microscopy, and anywhere engineers need to manipulate optical elements.
The motor was originally created for diode-pumped lasers. According to Equipment Solutions' president, Paul Swanson, the frequency of these lasers drifts during operation. By shining the light beam onto a grating before it exits the laser and manipulating the grating's angle, the device can correct for drift and keep the laser tuned to a single frequency.
The device has two elements, a voice coil motor and a flexure bearing attached to a lever. The motor consists of a magnetic housing and coil. Applying voltage causes the coil to move linearly along the length of the housing. As it moves, it pushes or pulls a flexure bearing. This moves the lever, which tilts the mirror plus or minus 5 degrees.
According to Swanson, the flexure bearing will last the life of the motor. It can oscillate or move to any fixed point, and achieves a smooth, linear velocity profile free of friction and stiction. An absolute angle electrooptic position sensor directly monitors the motion of the attached mirror or grating with microradian resolution and high repeatability.
Restricting the rotational angle to a maximum of 5 degrees enabled Swanson to shrink the size of the motor. By restricting motor and sensor operation to a narrow range of angles, Swanson was able to build a motor that responds faster and has more accurate sensor resolution.
The entire package, motor and integrated sensor, is tiny. It measures only 25 mm (1.0 in.) wide by 40 mm (1.5 in.) long. "It is much more compact than the galvanometers used for this application, and less costly. While its performance is not quite as high, it can fit into any pumped diode laser," Swanson said.
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|Title Annotation:||TECH FOCUS: Power Transmission & Motion Control|
|Comment:||Small voice coil motor drives laser mirrors.(TECH FOCUS: Power Transmission & Motion Control)|
|Author:||Brown, Alan S.|
|Date:||Mar 1, 2012|
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