Embedded Applications Requiring A Window - Motorola Symbol MiniScan MSXX07 Series Integration Manual

2 - 12 Symbol MiniScan MSXX07 Series Integration Guide

Embedded Applications Requiring a Window

Use the following guidelines for applications that require a window in front of the MiniScan.
NOTE Motorola does not recommend placing an exit window in front of the MiniScan; however, the following
information is provided for applications that require such a window.
Window Material
Many window materials that look perfectly clear can contain stresses and distortions that can reduce scanner
performance. For this reason, Motorola highly recommends only optical glass or cell-cast acrylic with an
anti-reflection coating. Following is a description of acrylic, and CR-39, another popular window material.
Table 2-2 on page 2-13
CAUTION
NOTE Do not use polycarbonate material.
Acrylic
When fabricated by cell-casting, acrylic has very good optical quality and low initial cost. However, protect the
surface from the environment as acrylic is susceptible to attack by chemicals, mechanical stresses, and UV light.
Acrylic has reasonably good impact resistance and can be ultrasonically welded.
CR-39
CR-39 is a thermal-setting plastic produced by the cell-casting process, and is commonly used in plastic eye
glasses lenses. CR-39 has excellent chemical and environmental resistance, including good surface hardness.
Typically it does not require hard-coating, but can be hard coated for severe environments. CR-39 has reasonably
good impact resistance and cannot be ultrasonically welded.
Chemically Tempered Float Glass
Glass is a hard material which provides excellent scratch and abrasion resistance. However, unannealed glass is
brittle. Increasing flexibility strength with minimal optical distortion requires chemical tempering. Glass cannot be
ultrasonically welded and is difficult to cut into odd shapes.
outlines the suggested window properties.
Consult an opto-mechanical engineer to recommend an appropriate window material and to
determine if coatings are appropriate for the specific application.