Specular Reflection - Motorola MK1250-0N0DAKBNTWR - Symbol Micro Kiosk MK 1250 Product Reference Manual

Ensure the symbol is in good condition.

Specular Reflection

When laser beams reflect directly back into the scanner from the bar code, they can "blind" the scanner and make
decoding difficult. This phenomenon is called specular reflection.
To avoid this, scan the bar code so that the beam does not bounce directly back. But don't scan at too oblique an
angle; the scanner needs to collect scattered reflections from the scan to make a successful decode. Practice
quickly shows what tolerances to work within.
Specular reflection.
Reflected beam is
within specular
dead zone and
prevents decode.
Avoiding Specular Reflection
Figure 1-9
When scanning a 1D bar code, there is only a small specular dead zone to avoid (+ 2
The specular dead zone is larger for scanning PDF417 (+ 9
not effective if its beams hit the bar code's surface at an angle greater than 30
Side Views
Tilt Bar Code At Slight Angle (Up to 30°)
o
from the direct laser beam). However, the scanner is
MK1200 Introduction 1 - 11
No specular reflection.
Decode can occur.
o
from the direct laser beam).
o
.