Sutter Instrument Lambda DG-4, Operation Manual

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LAMBDA DG-4 & DG-5 OPERATION MANUAL – REV.
3.05C
(
20150414
)
9
Figure 2-4. Light guide optical holder.
2.4 Loading Filters
2.4.1 Filter Orientation
The two sides of a filter are usually not identical due to differences in their surface coatings.
Some form of labeling will be present to differentiate the two sides. It is important to refer to
the filter manufacturer’s documentation to interpret the labeling and determine the proper
orientation relative to the light source. Remember, the light path inside the Lambda DG-4/5
travels from BOTTOM TO TOP. Therefore, the filters should be oriented with their “Lamp
Side” down.
2.4.2 Loading Filters
At the end of each filter holder is a filter cup assembly (shown below). There are at least two
items installed into the filter cup at the factory: a threaded retaining ring and a spacer ring
(to carry the force of the retaining ring to the unthreaded portion at the bottom of the cup).
In two of the filter cups, there will also be a blanking disc. Installation of filters into the filter
holders requires care and patience to avoid damaging the threads of the filter cups and
retaining rings as well as the filters.
Figure 2-5. Filter holder assembly.
The threaded retaining ring has two notches cut into it, 180 degrees apart. Place the notched
end of the brass spanner wrench into the notches on the retaining ring and carefully unscrew
it. If a retaining ring has been previously over-tightened, it is possible that the filter cup will
begin to unscrew from the slider. If this occurs, STOP. Turn the spanner wrench around and,
using the other end, insert it into the slots at the top of the cup. Then screw the cup back into
the slider. DO NOT push on the cup. Just screw it in until it seats firmly. It should then be
possible to remove the retaining ring.