Tutorials

The scan speed of a show laser light system is the maximum speed the mirrors on the Galvo motors can move at without distortion. It is measured in Points Per Second (pps), often stated as Kilo Points Per Second (1 kpps = 1000 pps).

To determine the optimal scan speed is difficult. The scan speed according to the ILDA specifications does not necessarily correlate with a proper show output quality. The value stated as ILDA standard is only valid for an 8° output angle. The scan angle of most scanner systems is much wider, up to 60° or even 80°. The behavior of the scanning system in different projection angles is not linear and every scanner type has different behaviour and a different relation between the scan angle and the corresponding optimal scan rate.

There are several approaches to determining the correct scan speed. The following procedure is quite common:

• Set the scan speed in the software to 50% of the value specified by the manufacturer (see manual of your show laser light system).
• Select a test figure with various different shapes. The test picture shall at least contain an L-shaped line, a rectangle, a circle and some single dots. It is recommended to use the test figures 11Ilda12K.bin or 12Ilda30K.bin in Laserworld Showeditor (please see Manual for details on how to find the test figures in Laserworld Showeditor):
  
  
• Project the test figure to a flat surface, like a wall or a screen, and listen to the sound of the moving scanners (turn off all other sound sources). Usually the selected figure is projected well (it’s normal that it flickers) and the buzzing of the scanner motors can be heard. Keep in mind how the sound is like.
• Increase the scan speed in the software by 1000pps (1kpps)
• Have a look at the projection and listen to the sound of the scanner motors: The flickering of the projection is reduced, but the look should have remained more or less the same. The corners are precise and detailed, the line beginnings and endings are clear and straight. Points are visible as points. The sound of the Galvos should have stayed more or less the same.
• Repeat the increase of the scan speed by 1kpps steps until:
• The look of the projection becomes bad and distorted and the sound of the Galvos becomes noticeably louder. Corners become round, points become fuzzy, circles noticeably decrease in size.
• On reaching this point, the correct scan speed has just been exceeded – so a reduction of the scan speed settings by 1kpps sets this correct scan speed.

If the determined scan speed appears to be too slow, there are several parameters that can be adjusted to optimize the output. See the Laserworld Showeditor Manual, Chapter “optimize Output”, to find out more about output optimization.

It is normal that the scan speed values specified by the manufacturer are sometimes different to the maximum scan speed determined with above described procedure. Due to many aspects that influence on the scanning behavior, each scanning system model should be calibrated individually in the software before use.