Laser/Piezo Autofocus System Offers Flexibility

Engineers at Motion X and Physik Instrumente (PI) have developed a laser-based system that combines Motion X's high-bandwidth autofocus sensor with PI's piezo-driven Pifoc objective and Z positioners. The modular and configurable architecture avoids image degradation and is suitable for commercial and custom microscopes and for substrates ranging from wafers with sensitive coatings to live biological samples. Achieving and maintaining a sharp focus can be a critical task for systems engineers and researchers.

Autofocus is important for users of standard microscopes and designers of custom optical columns alike, and some applications require real-time autofocus during processes in which the substrate is moved. Several approaches have been popular but can present drawbacks. Probe-based mechanisms compensate for drift by measuring the position of the sample plate versus the optical column, but are slow, cumbersome to set up, and limited in effective resolution due to the problematic probe/sample mechanical interface.

They also only maintain a mechanical setpoint and cannot correct for variations in sample thickness, drift between the probe and sample, parfocality errors between objectives, drift in the optics or the column itself, and so on. By comparison, optical autofocus techniques have the advantage of evaluating the image via the optics. All mechanical, thermal and optical issues which can impact focus, including changes and steps in the sample itself, are compensated. The teamwork between PI and Motion X joined Motion X's Focustrac system to PI's controls and piezo mechanics for plug-and-play autofocus capability.

PI's Pifoc piezo objective and z positioners are said to be typically 10 times faster than stepper or servo focusers and can realise full bandwidth capability of the Motion X laser autofocus technique. Different laser wavelengths are easily accommodated, the companies said, and mechanical options include objective positioners, turret positioners, sample-positioning and (well-plate) Z-stages and cost-effective OEM Z-positioning elements.


Popular posts from this blog

What is Class I Division 2?


7/8 16UN Connectors that Provide 600 Volts and 15 Amps