Scientific Grade Digital Video Camera
Chapter 9: Maintenance
ITN000089-D02, Rev H
Page 41
9.1.4. Cleaning the Infrared Filter (Standard and TE-Cooled Cameras)
The infra-red filter is visible when the lens is removed, mounted inside the lens mounting ring. This filter blocks
invisible, near-infrared light from reaching the CCD sensor. This is desirable in most applications where the
camera is imaging in the visible spectrum.
•
What must I do before cleaning the infrared filter?
Do not remove the filter from the camera.
First, remove the lens and carefully examine the filter in a clean location under a strong, direct light. Try to
determine if the contaminants are a few dust particles, oily smudge (such as fingerprints) or both.
•
What if the contamination is only a few dust particles?
Use a CLEAN, DRY (preferably brand-new), camel hair lens cleaning brush (such as those used by
photographers) to gently wipe the particles off of the filter.
•
What if the contamination includes a smudge?
1.
Remove the camera from the optical assembly and bring the camera to a clean, dry location
where it is safe to use flammable solvents (please see “Caution” below)
2.
Carefully loosen the lens mount lock ring using the supplied TSI lock ring wrench.
3.
Orient the camera so that the lens mount is pointing downward and carefully unscrew the lens
mounting ring and integral filter.
4.
Place the camera face down on a clean, dry surface to prevent particles from accumulating on
the CCD faceplate.
5.
Once the filter is removed, Use a CLEAN, DRY (preferably brand-new), camel hair lens cleaning
brush (such as those used by photographers) to gently wipe the particles off of the filter.
6.
Re-examine the filter after removing the dust. If a smudge is still visible, proceed by dipping a
clean, lint-free cotton swab in ethyl or isopropyl alcohol. The swab should be saturated, but not
dripping.
7.
Carefully draw the swab once across the surface, then rotate the swab 180 degrees to expose
the fresh surface and draw it across the filter surface again. Be careful not to pool alcohol on the
glass surface.
8.
Re-examine once again and repeat the process once, if necessary.
If contamination continues to be a problem, please call Thorlabs for assistance.
CAUTION
Ethyl and isopropyl alcohols are highly flammable! Do not use near extreme heat, arcing electrical
equipment (such as space heaters) or open flame! Use only with proper ventilation. Follow all safety
instructions provided by the manufacturer of the alcohol product.