Precision start-of-scan (SOS) detector for polygon scan heads

Polygon scanners capable of scanning hundreds of meters per second are needed to utilize the full capability of the latest high power Ultrafast and Ultra Short Pulse lasers.  To accurately process materials with a polygon scanner requires a Start-Of-Scan (SOS) detector. 

One issue is that the very bright/powerful working beam used in a Polygon Scan Head can interfere with the SOS laser detection.  With the new Precision Start-Of-Scan Detector, this is controlled with an integral detector isolation tube that blocks stray light except for a small operating aperture.  Should stray light entering the aperture cause interference, an optional band pass/reject filter can be installed in the tube.  This effectively solves the optical interference problem.

The other issue is loss of accuracy due to thermal effects.  In high power Polygon Scan Heads, the working beam and/or the hot working environment can elevate the temperature inside the scan head.  This can cause thermal drift of conventional SOS detectors.  Thermal drift will cause the starting position of the working beam to vary with temperature.  The new Precision SOS DetectorTM uses a temperature compensating bi-cell sensor to eliminate thermal drift accuracy error.

Precision Laser Scanning also offers an optional SOS laser matched to the SOS detector for power and spot size.  It is a compact red laser diode module that does not require focusing so it is easy to align within a Polygon Scan Head.


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