HP 8168E User Manual page 236

Cleaning Large Area Lenses and Mirrors
Caution
Some mirrors, such as those from a monochromator, are very soft and sensitive. Therefore, never
touch them and do not use cleaning tools such as compressed air or polymer lm.
Some lenses have special coatings that are sensitive to solvents, grease, liquid and mechanical
abrasion. Take extra care when cleaning lenses with these coatings.
Lens assemblies consisting of several lenses are not normally sealed. Therefore, use as little liquid
as possible, as it can get between the lenses and in doing so can change the properties of
projection.
1. Blow away any dust or dirt with compressed air.
Preferred
Procedure
Use this procedure particularly when there is greasy dirt on the lens:
Procedure for
Stubborn Dirt
Caution
Only use water if you are sure that your device does not corrode.
Do not use hot water as this can lead to mechanical stress, which can
damage your device.
Make sure that your liquid soap has no abrasive properties or perfume in it,
because they can scratch and damage your device.
Do not use normal washing-up liquid as sometimes an iridescent lm remains.
1. Moisten the lens or the mirror with water.
2. Put a little liquid soap on the surface and gently spread the liquid over the
whole area.
3. Wash o the emulsion with water, being careful to remove it all, as any
remaining streaks can impair measurement accuracy.
4. Take a new, dry soft-tissue and remove the water, by rubbing gently over
the surface using a small circular movement.
5. Blow away remaining lint with compressed air.
To clean lenses that are extremely sensitive to mechanical stress or pressure
Alternative
you can also use an optical clean polymer lm. This procedure is
Procedure A
time-consuming, but you avoid scratching or destroying the surface.
1. Put the lm on the surface and wait at least 30 minutes to make sure that
the lm has had enough time to dry.
2. Remove the lm and any dirt with special adhesive tapes.
If your lens is sensitive to water then:
Alternative
Procedure B
1. Moisten the lens or the mirror with isopropyl alcohol.
2. Take a new, dry soft-tissue and remove the alcohol, dissolved sediment and
dust, by rubbing gently over the surface using a small circular movement.
3. Blow away remaining lint with compressed air.
E-10 Cleaning Procedures