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4
Optics and Illumination
Window Placement
Distance from Window
The window should be mounted close to the front of the image engine (parallel, no tilt). The maximum distance is measured from
the front of the imager housing to the farthest surface of the window. Since unwanted reflections can occur at either surface and
the window thickness can vary, the further side is the worst case.
Uncoated Window (or inside only coated):
Coated Window (or outside only coated):
Other window position solutions are possible provided the imager frame rate is tightly controlled. When frame rates are restricted
to 15fps - 30fps, the window may be placed at distances of 7.62mm (.3") and farther as follows:
Distance to Window (measure to the farthest surface from engine)
Distance mm (in)
Window Tilt (deg)
Coated or Uncoated at 0.5 mm - 2 mm thickness
Note: Frame rates less than 15fps will cause any minor defects in the window to be visible in the image. These resulting image
defects will adversely affect reading performance.
There are no solutions for engine-to-window distances of 3mm to 7mm. Window tilt angles required to eliminate reflections will
cause the window to come into physical contact with the engine housing over this range of window distances.
Window Size and Material Requirements
1.
The window should be polycarbonate or a harder material for portable applications.
2.
Window material must be clear. Clarex (cast acrylic) is preferred. Polycarbonate and CR39 are also acceptable.
3.
A minimum thickness of .03 inches (.076 mm) is recommended for this window, with a maximum allowable thickness of
.062 inches (1.57mm). These dimensions prevent reflections from the window that can be seen by the camera.
4.
We strongly recommend using a window with anti-reflective coating on both sides of the window. Transmission should be
98% (average) from 400 nm to 700 nm. If only the outside of the window is coated, the inside uncoated surface is consid-
ered the worst case. If the outside surface of the window is uncoated, it must be treated as a completely uncoated window.
5.
Window clear aperture shown in the Window Size Diagram below is for the location shown. The window size must
increase as it is moved away from the optics module to accommodate the aiming and illumination envelopes shown.
Note: The integrator must take care that the inside of the housing is not shiny. A dark matte finish is recommended for the region
in front of the engine, which could generate its own source of light reflections.
IMAGETEAM™ 4X00 Series Integration Manual
1.5 mm
3.0 mm
7.62 (0.3)
12.7 (0.5)
38
30
38.1
25.4 (1.0)
50.8 (2.0)
(1.51)
22
19
18
4 - 1
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