POLYGON SCAN HEAD – BLOCK DIAGRAM

When galvanometer (galvo) scanners are not fast enough, a Polygon Scan Head may be the solution.  A Polygon Scan Head can scan at hundreds of meters per second.  Here is a block diagram of a single axis Polygon Scan Head.  It may produce 2 axis imaging when combined with a moving target such as a roll to roll material processing application.

The laser beam enters through a beam expander to set the desired beam diameter.  The beam expander can also adjust the beam divergence.  

Optional refractive beam shaping can change the beam energy profile from Gaussian to flat top or donut or in between.  Refractive beam shaping has the lowest energy loss. Many applications can benefit from beam shaping.  

The beam is then scanned using a high speed polygon scanner and focused at a flat target using an F-Theta lens.  The non-reciprocating polygon scanner can achieve scan speeds greater than 10 times that of galvo scanners.  This high scanning speed may be required to utilize the full potential of high power and Ultrafast / USP lasers.

Galvo scanners require absolute encoders to operate accurately.  Polygon scanners require Start-Of-Scan (SOS) detection for accurate scanning.  The SOS laser and detector will be out of plane from the high power working beam to avoid interference or damage to the detector.  In a high power system, the detector may use shielding and filtering to block stray light from working beam.

Precision Laser Scanning can provide all of these optics as well as advice for you to build a Polygon Scan Head for your high speed laser scanning application.  Feel free to ask questions.  Contact us at info@precisionlaserscanning.com or 1-480-515-1643.