Mlt-Dpm Illuminator - Datalogic Matrix 300N Series Product Reference Manual

ILLUMINATORS

MLT-DPM ILLUMINATOR

This is both a Bright Field and a Dark Field illuminator available for 1.3 MP models.
The MLT-DPM illuminator is made up of 63 LEDs divided into two groups of four sectors
each, independently controlled by the software application.
Four sectors of six LEDs each make up the internal group called Central LED Group and
correspond to Bright Field illumination. The operating distance range is typically from
20 to 250 mm. The reader focus distance further limits this range.
The use of the MLT-DPM Central LED Group is particularly effective in direct part mark
applications (DPM), where linear machining flaws are present on the part surfaces. In
these cases, an image of the code can be obtained having a very light background.
The other four sectors make up the external group called Peripheral LED Group and cor-
respond to Dark Field illumination. Dark Field illumination is guaranteed by the 39 side-
emitting blue LEDs divided as follows: a TOP sector of 7 LEDs, a BOTTOM sector of 8
LEDs and two sectors (LEFT and RIGHT) of 12 LEDs each.
The Peripheral LED Group can be the correct solution for DPM applications with highly
reflective surfaces. In these applications, by using a traditional bright field illuminator,
the code can result unreadable because in the acquired image some parts of the code
are made invisible due to gray-level saturation generated by direct reflection of the illu-
minator LEDs.
To obtain optimum Dark Field illumination, it is necessary to work at close range, typi-
cally in the range from 20 to 50 mm. The reader focus distance further limits this range.
An orange filter is applied over the Central LED Group in order to avoid harmful blue
light reflections off the Peripheral LED component packages.
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MATRIX 300N
Figure 108 - 39/24-LED MLT-DPM Illuminator