Rockwell Automation 2755 2D Hand-Held Scanner - Manual (Page 44)

3–6 Operating the Scanner
Publication 2755-6.4
Specular Reflection
When the laser beam reflects directly back into the scanner from the
decode, it can blind the scanner and make decoding difficult. This is
called specular reflection.
To avoid this, scan the bar code so that the beam does not bounce
directly back. Do not scan at too oblique an angle; the scanner needs
to collect scattered reflections from the scan to make a successful
decode. Simple practice shows what tolerances to work within.
Tilt Back at Slight Angle (up to 30 _)
1. Specular reflection; reflected
beam interferes. 2. No specular reflection. Decode
can occur.
Avoiding Specular Reflection
Bar Code Bar Code