Chapter 2 Individual Operations
62
Chap. 2
Individual Operations
Filter Cube Motion Restricting Lever Functions
Lever
position
Filter cube switching
A1
-
2
-
3
-
4
B1
-
2 / 3
-
4
C 1
-
2
-
3
-
4
1
1
4
2 3 4
CUBE
A1
-
2
-
3
-
4
B1
-
2 / 3
-
4
C1
-
2
-
3
-
4
Lever position
Position A
(Push in by
two notches)
Locked
(filter cubes cannot be switched)
Position B
(Push in by
one notch)
Switching between positions 1 and 2, or
between positions 3 and 4 only. (The position
at which the lever is pushed in determines
whether switching is for positions 1 and 2 or
positions 3 and 4.)
Position C
(first click
stop position)
Free (switching possible as desired)
17.2
Selecting Filters
filter cube consists of three types of optical components: an
excitation filter (EX filter), a barrier filter (BA filter), and a dichroic
mirror (DM). Select the filter cube with the desired combination o
optical components to suit the characteristics of the sample and
the fluorophore by referencing the properties of each filter.
You can select a combination of an excitation filter and a barrier
filter even if you are using the same excitation method.
Excitation filters, barrier filters, and dichroic mirrors can be
purchased separately.
Since excitation filters are exposed to strong light during
operations, they will deteriorate over time. Replace the filter at
intervals determined by usage.
UV-2A
EX 330-380
DM 400
BA 420
Filter cube
Spacer inside the filter cube
Some types of filter cubes cannot be inserted directly into the epi-fluorescence attachment.
Follow the procedure described in Chapter 3, “6 Assembly for Epi-fluorescence Microscopy - ■ Attaching a filter cube”
to remove an internal spacer or reverse the spacer before insertion.
Excitation filter (EX filter)
Excitation filters allow selective transmission of light (excitation
light) in the wavelength range required for fluorescent light
emissions from the specimen, blocking light of all other
wavelengths. The range of wavelengths allowed to pass through
a filter is referred to as the bandwidth.
The bandwidth range of an excitation filter determines the
brightness of the fluorescent image, the generation of
autofluorescence (fluorescence resulting from substances other
than the fluorophores), and degree of fading. The broader the
bandwidth, the greater the amount of excitation light irradiated
onto the specimen, thereby increasing the brightness. However,
this also increases the amount of autofluorescence and causes
faster color fading. Narrow bandwidth reduces the amount of
excitation light striking the specimen and causes the image to
appear darker, but reduces autofluorescence and fading. For
specimens with pronounced auto fluorescence, use excitation
filters with a narrow bandwidth. (However, the fluorescent image
will be darker.)
Since excitation filters are exposed to strong light during
operations, they will deteriorate over time. Replace the filter at
intervals determined by usage.
EX filter bandwidth
Excitation filte
Barrier filter
Dichroic mirror (inside the cube)
EX filte
Bandwidth
Spectral
transmission
Wavelength
0
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