Table of Contents
Advertisement
1M30P Camera User's Manual
6.
7.
8.
Protecting Against Dust, Oil, and Scratches
The CCD window is part of the optical path and should be handled like other optical
components, with extreme care.
Dust can obscure pixels, producing dark patches on the sensor response. Dust is most
visible when the illumination is collimated. The dark patches shift position as the angle
of illumination changes. Dust is normally not visible when the sensor is positioned at the
exit port of an integrating sphere, where the illumination is diffuse.
Dust can normally be removed by blowing the window surface using clean, dry,
compressed air, unless the dust particles are being held by an electrostatic charge, in
which case either an ionized blower or wet cleaning is necessary.
Oil is usually introduced during handling. Touching the surface of the window
barehanded will leave oily residues. Using rubber fingercots and rubber gloves can
prevent contamination. However, the friction between rubber and the window may
produce electrostatic charge that may damage the sensor. To avoid ESD damage and to
avoid introducing oily residues, only hold the sensor from the edges of the ceramic
package and avoid touching the sensor pins and the window.
Improper handling, cleaning or storage of the sensor can cause scratches. Vacuum
picking tools should not come in contact with the window surface. CCDs should not be
stored in containers where they are not properly secured and can slide against the
container.
Scratches diffract incident illumination. When exposed to uniform illumination, a sensor
with a scratched window will normally have brighter pixels adjacent to darker pixels. The
location of these pixels will change with the angle of illumination.
Cleaning the Sensor Window
1.
2.
3.
4.
DALSA
Ground all tools and mechanical components that come in contact with the CCD.
DALSA recommends that CCDs be handled under ionized air to prevent static
charge buildup.
Always store the devises in conductive foam. Alternatively, clamps can be used to
short all the CCD pins together before storing.
The above ESD precautions need to be followed at all times, even when there is no
evidence of CCD damage. The rate which electrostatic charge dissipates depends on
numerous environmental conditions and an improper handling procedure that does
not appear to be damaging the CCDs immediately may cause damage with a change
in environmental conditions.
Use clean, dry, compressed air to blow off loose particles. This step alone is usually
sufficient to clean the sensor window.
If further cleaning is required, use a lens wiper moistened with alcohol.
We recommend using lint free, ESD safe cloth wipers that do not contain particles
that can scratch the window.
Wipe the window carefully and slowly.
36
03-32-10001-02
Advertisement
Table of Contents
