Olympus FHT-521 User manual

OLYMPUS RESEARCH MICROSCOPES
INSTRUCTION MANUAL
MODELS FHT&EHTWITH§W:

INSTRUCTION MANUAL
OLYMPUS RESEARCH MICROSCOPES
MODELS
FHT&EHT:~~:~~
TABLE OF CONTENTS
I. STANDARD EQUIPMENT " 2
II. SPECiFiCATiONS 4
Ill. IDENTIFICATION OF VARIOUS COMPONENTS 5
IV. DESCRIPTION OF EACH COMPONENT 6
V. OPERATING THE MICROSCOPE
14
VI. OPTICAL CHARACTERiSTICS ...............•...... ·19

I
STANDARD EQUIPMENT
Before assembly, please check your standard outfit, which consists of
the following items:
1. Model FHT
, ) Binocular Tube Versions
Con- Total
Model No. Eyepieces Objectives Stage denser magni-
fication
Bi P7x, Bi WF lOx, Ach
4x,Ach lOx,
N.A. 28x-
FHT-521 Bi P15x, paired Ach 40x. 1.25 1500x
Ach l00x (oill
Bi P7x, Bi High-Eye- Ach
4x.Ach lOx, FrS
N.A. 28x-
FHT-522 pointWF 10x,Bi P15x, FI 40x, FI 100x ISquare 1.40 2000x
Bi
K20x. paired
loill
mechani·
Bi P7x, Bi High-Eye- Plan 4x. Plan lOx,
cal stage
with left N.A. 28x-
FHT-523 pointWF lOx. BiP15x. Plan 40x,
&right 1.40 2000x
Bi
K20x, paired Plan loox loill
hand
coaxial N.A.
Plan4x,Plan lOx.
controls) 0.85
FHT-523- Bi SW10x, paired Plan
20x, Plan40x with
40x-
SW SW
Plan looxloill
aux. con
l000x
denser
lens
2} Trinocular Tube Versions
Con- Total
Model No. Eyepieces Objectives Stage
denser
magni-
fication
Bi P7x, BiWF10x,
Bi P15x. paired
Ach 4x, Ach lOx,
N.A. 28x-
FHT-531 Photo eyepieces: Ach 40x,
1.25 1500x
FK2.5x, FK3.3x Ach 100x (oill
FK5x,FK6.7x, leach
Bi P7x, Bi High-Eye- FrS
point WF10x, Bi P15x,
Ach4x,Ach lOx, (Square
FHT-532 Bi
K20x, paired
FI40x,Fll00x
mechani-
N.A. 28x-
Photo eyepieces:
loill
cal stage 1.40 2000x
FK2.5x, FK3.3x.
with left
FK5x,FK6.7x,l each &right
Bi P7x, Bi High-Eye- hand
coaxial
point WF lOx, Bi P15x, Plan4x, Plan lOx. controls)
FHT-533 Bi
K20x. paired Plan
40x,
N.A.
28x-
Photo eyepieces: Plan
l00x loill
1.40 2000x
FK2.5x, FK3.3x,
FK5x,FK6.7x,l each
N.A.
SW10x paired
Plan4x,Planl0x,
0.85
FHT-533-
Photo eyepieces: Plan20x.Plan40x, with 40x-
SW
FK2.5x, FK3.3x,
SWPlan looxloill
aux. con· looox
FK5x,FK6.7x,l each denser
lens.
Other items supplied with each version:
Spare Bulbs,6V.5A,
TB-' _. _. .. 2pcs.
Filter(blue) ..... .................. .. , pc.
Filter Mount (provided only with achromatic/aplanatic condenser) 1pc.
Wooden Carrying Case. . 1
pc.
Certificate . . . . . 1 pc.
2

2. Model EHT
, ) Binocular Tube Version
Can· Total
Model No. Eyepieces Objectives Stage denser magni-
fication
Bi P7x, Bi WF10x.
Ach4x, Ach lOx.
N.A. 28x-
EHT -421 Ach 40x.
8i P15x, paired Ach
loox (oill
1.25 1500x
CrS·VH
Bi P7x,
BI High·Eye· Ach4x. Ach lOx ISquare N.A.
28x-
EHT-422 pointWFl Ox. Bi Pl 5x. FI 40x. FI loox
mechani- 1.40 2000x
Bi
K20x. paired loill cal stage
Bi P7x, Bi High·Eye- Plan 4x. Plan lOx.
with co-
axial low N.A. 28x-
EHT -423
pointWF 1Ox.Bi Pl 5x. Plan 40x.
drive 1.40 2000x
Bi
K20x. paired Plan loox loill
controls) N.A.
Plan
4x. Plan lOx.
0.85
EHT -423· with
40x-
SW
Bi SW10x. paired Plan20x.Plan40x, aux.
con·
looox
SWPlan looxloill
denser
lens
2) Trinocular Tube Version
Con- Total
Model No. Eyepieces Objectives Stage denser magni·
fication
Bi P7x. Bi WF lOx,
Bi P15x. paired. Ach
4x. Ach lOx,
N.A.
28x-
EHT -431 Photo eyepieces :
Ach40x,Achloox
1.25 1500x
FK2.5x,FK3.3x,
(oill
FK5x,FK6.7x,1 each
Bi P7x. Bi High·Eye-
pointWF10x, Bi P15x,
Ach4x,Ach lOx,
CrS·VH
EHT-432 Bi
K20x, paired. FI
40x. FI loox
(Square
N.A. 28x-
Photo eyepieces:
(oill
mechani- 1.40
2000x
FK2.5x, FK3.3x,
cal stage
FK5x, FK6.7x, 1each
with low
Bi P7x, Bi High·Eye- drive
controls)
pointWF10x, Bi Pl 5x, Plan
4x, Plan lOx,
EHT-433
Bi K20x, paired. Plan
40x,
N.A. 28x-
Photo eyepieces :Plan
loox (oil)
1.40 2000-
FK2.5x, FK3.3x,
FK5x, FK6.7x,l each
N.A.
Bi SW lOx, paired. Plan4x, Plan
lOx,
0.85
EHT·433· Photo eyepieces: Plan
20x ,Plan40x,
with 40x-
SW
FK2.5x, FK3.3x
SWPlan lOOx(oill
aux. con- 1000x
FK5x, FK6.7x,l each
denser
lens
Other items supplied with each version:
Spare
Bulbs,6V,5A.TB·' 2pcs.
Filler(blue) .................................... .. , pc.
Filter Mount(provided only wilh achromatic/aplanalic condenser) 1 pc.
Wooden Carrying Case. 1pc.
Certificate . . . . . . . . 1
pc.
3

II
SPECIFICATIONS
~
--------
FHT EHT
Vertical stage movement. Vertical stage
movement.
Focusing coax
ial coarse and fine ad· separate coarse and fine
justments, with automatic adjustments. with auto-
pre·focusing lever. matic pre-focusing lever.
Coarse
Devetait slideways, rack and pinion type:
adjustment adjustment range 32.5 mm
Fine Adjustment ragne
1.2mm. Adjustment range
1.2mm,
adjustment graduated in increments
of
graduated in increments of
Micra-
1 micron. 2microns.
scope Tungsten lamp, 6V. 5A, with centering device and built·in
Stand Light transformer.
source Auxiliary
lenses for low,
medium and high power
objectives.
Revolving Quintuple, on ball bearings. Engravings. coded Ato E.
nosepiece to facilitate objective insertion.
Condenser With condenser centering device and rack·and-pinion
mount
height adjustment. Height displacement 23.5mm.
Tube inclination 45-, rotatable 360-, both eyepiece tubes
Binocular provided
with diopter and tube length adjustments,
tube except Bi-SW observation tube inclined
30-, and diopter
Obser- difference can be adjusted
by the SW eyepiece tube.
vation I nterpupillary distance adjustment from 56mm to 74mm.
Tubes
Tube inclination 45·, rotatable 360·, both eyepiece tubes
provided with diopter and tube length adjustments, except
Trinocular Tr-SWobservation tube inclined 30·, and diopter difference
tube
can be adjusted by the SW eyepiece tube. Interpupillary
distance adjustment from 56mm to 74mm, with photo
tube. Light path selector lever.
FrS
CrS·VH
Rotatable graduated mech· Rotatable graduated mech·
Stages
anical stage with horizontal anical stage with low drive
drive controls, movement controls, movement range
range 44mm x 76mm. Ver· 52mm x 76mm. Vernier
nier scales reading to O. 1 mm scales reading
to 0.1mm.
Achromatic! NA 1.40, with decenterable aperture iris diaphragm and
aplanatic graduated scale.
condenser
Can·
Abbe N.A. 1.25, with aperture iris diaphragm and swing-out
densers condenser filter
mount.
CO-4
N.A. 0.85, for super widefield of view,
with variable
condenser aperture iris diaphragm, filter holder
and auxiliary
condenser lens.
Photo Eyepieces FK
The new photo eyepieces FKare specially designed for photo-
micrography with the Olympus Photomicrographic System Camera Model
PM-10
(optional). The eyepiece powers available are 2.5x, 3.3x, 5x
and 6.7x. Each magnification is computed to focus an image at aprojec-
tion length of 125mm - the same plane as the 35mm film plane, thus
compensating spherical aberration.
The respective magnifications
are engraved on the FKeyepieces:
Total magnification of a picture
when the FK eyepiece is used. is formulated as follows:
Total magnification with 35mm film =Objective power x FK eye-
piece power.
The formula below, however. will be applied in case the camp.ra
adapter with relay lens, model PM-D L, is used for larger format
camera backs:
Total magnification of.large format picture =Objective power x FK
eyepiece power x3.
4

III
IDENTIFICATION OF VARIOUS COMPONENTS
Trinocular Observation Tube
Limb
Voltage
Adjustment
Knob
FHT·533
5
Eyepiece
Revolving
Nosepiece
Objective
5'"",
Conden~r
Voltmeter

IV
DESCRIPTION OF EACH COMPONENT
A. Mic:roMlOpe Sund
1. Limb 8nd Focusi"9 Mech..,ism
The limb is securely attached to the sturdy base and supports the observa-
tion tube, stage, condenser, revolving nosepiece and focusing mechanism.
The focusing mechanism includes
the coarse and fine adjustments and an
automatic pre-focusing lever. This lever
is provided to prevent possible
contact between specimen and objective as well as
to simplify coarse
focusing.
The lever is locked after coarse focus has been accomplished.
This prevents further upward travel
of the stage and automatically pro-
vides alimiting
stop if the stage is lowered then raised again. The
automatic pre-focusing lever does not restrict fine focusing.
The filter
mount is plaoed on the light exit of the illuminator base.
Stage Clamping Lever
Co_
Adjustment Knob
Fine
Adjustment Knob
Automatic
Pre-focusing Lever
FHT
Aux iI iory Lens
Shifting Lever
Fillllr Mount
Light Exit
Coane
Adjustment Knob
Fine
Adjustment Knob
2. Condenser
The condenser may be mounted on the condenser mount by first
inserting
the condenser into the condenser mount from below, aligning
the positioning dots on the condenser and condenser mount, and then
clamping with
the clamping screw. Condenser centration can be
accomplished by means
of two centering knobs. Vertical movement of
the condenser can be adjusted by the condenser height adjustment knob.
The condenser has an excellent resolving power,
dry or oil immersion,
from
4x to 100x magnification objectives. When using the 100x
objective,
the distance between condenser and specimen should be
filled with immersion oil.
Note: For use with
the achromaticlaplanatic condenser N.A. 1.40, the
filter
mount is placed on the light exit of the illuminator base, while
either
the Abbe N.A. 1.25 or N.A. 0.85 condenser incorporates its
own filter mount. When the N.A. 0.85 condenser is used for super
widefield observation, keep
the auxiliary condenser lens slipped on the
light exit on the base.
The slide clamping screw permits simultaneous locking of slide and
6

rotation of condenser and the slide lever allows decentering and rotating
the aperture iris diaphragm for obligue illumination.
• Abbe Conden5el", N.A. 1.25
Abbe COI"denser --------
Condenser Clamping
Screw
Centering Knob
Filter Moun't-~--'
• Achromatic/aplanatic Condenser, N.A. 1.4
Achromaticl
aplanatic
Condenser -------
Condenser
Clamping
Screw ----~-.
Centering Knob
Aperture Iris
Diaphragm
Cuntrol Aing-~-r-'
•CD-4 Condenser, N.A. 0.85
Condenser
Condenser
Mount
Aperture Iris
l..::> ... _---- Diaphragm
Control lever
,,~~- Alignment Dots
/Condenser Mount
Slide Clamping
Screw
~ ...... Alignment Dots
----Slide Lever
Condenser MOllnt
Condenser Clamping
Screw
Centering Knob
Filter Mount
Alignment Dots
Aperture Iris
Diaphragm Control
Leve<
7

Lever Position
H
L
Fo,
Photomicrography
4x
lOx Observ.
20x-l00x
Objective For
Observation
3. Microscope Base and· Light Source
1) Microscope
Base
The lamp house is built onto the base. The lamp socket is clamped to
the lamp house with adamping screw. The tight path is selected with
the auxiliary lens shifting lever for high, medium and low magnification
of objective in use.
... __ ..
It is generally recommended to set the lever to the position marked with
"Observ." (equivalent to position L) for brightfield observation with
all the objectives from 4x through 100x. In phase contrast or darkfield
observation, where
in tenser light is required, however, it is recommended
to set it to position M or Haccording to objective magnification as in
case with photomicrography.
Voltage
Adjustment Knob
Grounding terminal
..::::::;::;",::::~-- Line Voltage
Adjustment Screw
oVoltage Adjustment
The
minimum voltage required for the light source can be varied qv
means of the line voltage adjustment screw provided at the back of the
microscope
base in accordance with the line voltage and frequency,
since asilicon controlled rectifier (SeRl
is .adopted in the dimmer
circuitry.
At the bottom of the base is avoltage selector switch, which can be
turned with acoin, to correspond with the voltage of main supply
(11 OV, 120V, 220V or 240Vl. The transformer is built in the base and
switched on and
off with the voltage adjustment knob, which also
controls the bulb voltage from 0
to lOV.
8

•
2 ) Light Source
The light source consists
of lamp house CD and lamp socket ® .
The lamp socket is provided with two coaxial lamp centering knobs
@ _ The Jamp socket can be moved back and forth along the optical
axis to eliminate uneven illumination in the field of view.
a. Electric Connection
1) Insert the jacks of the lamp cord into the low voltage outlet at
the back of microscope base.
2) Insert the plugs of the line cord into the tine cord socket and the
AC po......er outlet respectively.
b. Adjustment of Line Voltage
1) Turn the voltage adjustment knob clockwise to position ON.
2) If the bulb is dimmly lit. the line voltage is proper, and you have
only to manipulate the voltage adjustment knob in order to obtain
optimum light intensity. with no need to further proceed to the
following procedure 3).
3) Even after the voltage adjustment knob is turned on, if the bulb
does not light or lights up bright immediately after switching on,
rotate gradually the line voltage adjustment screw (at the back
of
the base) with acoin, until the lamp dims.
oAccording
to the fluctuations of line voltage and frequency
(SO/60Hz),
minimum voltage required for lighting the bulb
varies;
if the bulb does not light at all or lights up immediately
after switching on, re-adjustment
of the line voltage screw is
necessary to dim the bulb.
Note: For light intensity adjustment after dimming the bulb,
use the voltage adjustment knob on the side of the base.
c. Attach the tamp socket.
1) Loosen the clamping screw <!) .
2) Insert the lamp socket @ into the lamp house CD .
3) Tighten the clamping screw to secure the socket.
9

4. Low Voltage Indication
~' ~ 1
5;; 1 8 9 10
Meter indicates 3V.
Meter indicates 6V,
As the voltage adjus~ment knob is turned clockwise, the red zone
advances as shown above. Use·the upper scale of the meter to read from
o to 5V, and the lower scale to read from 5V to lOV. Avoid prolonged
use at voltages above 6V.
Lamp Replacement
l 1) Loosen the socket clamping screw and slide out the socket.
l2l Remove the bulb by slightly depressing it against the seat and
then rotating it in acounterclockwise direction.
(3l Insert areplacement bulb in reversed order.
Before
use, wipe off thoroughly any fingerprints or stains on
the bulb.
5. Revolving Nosepiece
The Quintuple revolving nosepiece rotates on ball bearings.
Aknurled ring
is provided for slip-free and smooth rotation.
Each objective clicks Into position accurately, maintaining proper
optical alignment. Also
each objective hole is coded with the letters
A,
8, C, D and Ein order to indicate where the objectives should be
mounted, as "A" is for 4x, "B" for lOx, "C" for 20x, "0" for 40x
and "E" for 100x In addition, the observer can easily tell what
power objective is being used by the color band engraved un each
objective during observation.
Magnification 4x
10, 20,
HlQ,
Color band Red Orange Yellow Brilliant green Light blue
*The stage must be mounted on the microscope prior to the mount
ing of objectives on the revolving nosepiece.
'0

B. Observation Tubes
The observation tubes
are inclined 45" (except Bi·SW and Tr-SW both
inclined 30°) and rotatable 360°. The tubes
can be clamped in any
direction
with the clamping screw provided.
For adjustment
of interpupillary distance. hold the right and left
eyepiece tubes with both hands and push the tubes together or
pull them apart laterally, whichever is required, while looking at an
image through the eyepieces with both eyes, until perfect binocular
vision
is obtained. It is good practice to memorize the individual
interpupillary distance. setting. A
scale for this purpose is located
between the eyepiece tubes. (The mechanical tube length
of the SW
observation tubes is 160mm when this scale is set at 62.l The eyepiece
tubes
are provided with diopter and tube length adjustment rings.
A
light path selector lever to direct the light to observation tube or
photo tube, is provided with the trinocular observation tube.
Photo Tube
Light Path Selector lever
;:::===--- Diopter Adjustment Rings
Clamping
Screw---tllIO'lt __
Eyepiece Tube
Knurled Ring,--"'-\
11
~Knurled Ring
-r- Eyepiece Positioning Groove
Interpupillary
Distance
Scale
Clamping Screw

Clamping Screw -~~~~~~-.!J!!~~~-
Photo Tube
Ujht Path
Se ector Lever
C. Stages
1. Square Mechanical Stage FrS
This is asquare coaxial drive control mechanical stage with interchange-
able mount. The specimen
is moved by means of horizontal drive controls
on both
sides of the stage. The larger control knob is for north-south (Y)
movement
of the specimen, and the smaller control knob is for east-west
(X) movement.
The working
range of the specimen holder is:
North-south excursion ... 44mm
East-west
excursion. . .. .76mm
Each control is provided with a scale (0-50 for Yexcursion, 50-120 for
Xexcursion) and avernier, reading to 0.1 mm. Stage rotation can be
clamped by aclamping screw. The stage may be used as aplain stage by
removing the specimen holder assembly.
Graduated Scale for
North-South Movement
Stage Rotation
Clamping Screw
Graduated Scale
for
East-West Movement
-------
Specimen Holder
Clampinq Screws for
SpeCimen Holder
North-South Movement
Control Knob
East-West Movement
Control Knob
Movement
Control Kno
*The stage may be mounted on the microscope in reversed position, as
shown in the picture above, right, to obtain increased rotation.
'2

2. Square Mechanical Stage with Low Drive Controls CrS-VH
The specimen is moved by means of coaxial low drive control knobs
which are provided on'the stage vertically.
The working range of the specimen holder is:
North-south excursion , 52mm
East-west excursion 76mm
Each control is provided with ascale 10-60 for Yexcursion, 6O~ 13)
for Xexcursion) and avernier, reading to 0.1 mm.
Stage rotation: After bring the specimen slide in position, move the center
of the specimen slide into the optical axis. then rotate the stage horizontally.
The stage rotation can be clamped by means of aclamping screw.
The stage may be used as aplain stage by removing the specimen holder.
Graduated Scale
for East-West
Movement __ .... '"
North.south
Movement
Control Knob
East-West
Movement
Control Knob
Specimen Holdel"
Clamping Screw for
Stage Rotation
~ ~=~l",:;;e;';f,or Rotation
ruat Scale for
'-- ~"'onh-SolJth MovemeoJ
Stage Clamping lever
3, Square Mechanical Stage with Low Drive Controls Cs-VH
This mechanical stage is operated by coaxial low drive controls on
rack-and-pinion for north-south and east-west movements. The working
range of the specimen holder IS the same as that of the CrS-VH.
4, Square Coaxial Mechanical Stage CS
Thp- mechanical stage CS is operated by coaxial horizontal control
knobs with rack-an"d-pinion for north-south movement and alead screw
for east-west movement.
5. Mount the Mechanical Stage
1) Lower the condenser mount as far as possible with the condenser height
adjustment knob.
2) Lower the stage dovetail slide all
the way with the coarse adjust-
ment knobs.
3) Insert the dovetail mount of the
stage slowly into the stage dovetail
slide all the way down. and lock
the stage with the locking lever
provided on the dovetail mount
of the stage.
13

yOPERATING THE MICROSCOPE
A. Interpupillary Distance and Diopter Adjustments
In order to obtain perfect binocular vision through the eyepieces, it is
necessary to adjust interpupillary distance and diopter difference in eye
acuity; otherwise, long time observation would put considerable strain on
the obser'.;er's eyes.
1. I nterpupiltary 0istance Adjustment
(1) Hold the (igh tand lefteyepiece tubes with both hands and push the
tubes together, or pull them apart laterallY,whichever is required,
while looking through the eyepieces with both eyes, until perfect
binocular vision is obtained.
(2) Memorize your interpupillary distance setting. Scale CD is provided
for this purpose, located between the eyepiece tubes.
* This interpupillary distance adjustment is necessary each time
observers are changed. Re-focusing is also necessary whenever the
interpupillary distance is changed.
2. Diopter Adjustment
a. For FHT and EHT
(1) Rotate the diopter ring ® on the right eyepiece tube to match the
scale on the ring to your interpupillary distance setting which you
obtained from scale CD as described in the preceding paragraph
1-121
(2) Look at the image through the
right eyepiece with your right
eye and focus on the specimen
with the fine adjustment knobs.
(3) Next, look at the image through
the left eyepiece with your left
eye and rotate the diopter ring@
to focus on the specimen with-
out using the coarse and fine
adjustment knobs.
b. For FHT-SW and EHT-SW
Each SW eyepiece is provided with
diopter ring for adjustment of your
diopter difference.
(1) Rotate the diopter ring on the
right eyepiece tube to obtain
aclear image of the field of
view in the eyepiece.
(2) Look at the image through the
right eyepiece with your right
eye and focus on the specimen
with the fine adjustment knobs.
(3) Next,look at the image through
the left eyepiece with your left
eye and rotate the diopter ring
to focus on the specimen with-
out using the coarse and fine
adjustment knobs.
14

B. Center the Condenser and the Light Bulb
After all necessary components are attached to the microscope stand
properly
and securely, it is essential to center the condenser and the
light bulb before the microscope
is put in operation.
1. First, make sure that all electrical conne~tions are done property,
then turn the switch
in the microscope base to the ON position.
The lamp
will light up. By raising the voltage progressively, you can
ascertain that the bulb is on.
Adjust light intensity to suit your requirements.
2. Swing the auxiliary lens shifting lever on the illuminator base to posi-
tion Observ.
3. Place aspecimen on the stage and use the objective lOx to bring the
specimen in focus.
o
Out of center.
o
Centered. Opened
fu lIy.
4. Stop down the field iris diaphragm with the field iris diaphragm
control provided on the microscope
base. Aslightly blurred image
of the field iris diaphragm can now be seen in the field of view.
5. Move the condenser up and down with the condenser height
adjustment knob
to focus on the image of the field iris diaphragm.
;(;rvvv,
\"IJU<NUUU/
Before centration.
After centration.
6. While widening the diameter of the field progressively, use the con-
denser centering knobs
to bring the diaphragm image into the center
of the field of view. If the polygonal image of the irisdiaphragm
becomes inscribed in the field
it means that the field iris diaphragm is
centered. Slightly increase the diameter of the field iris diaphragm
until it is iust outside the field of view.
7. Remove one of the eyepieces from the observation tube, and look into
the eyepiece tube
so that the filament image of the bulb at the rear
focal plane
of the objective can easily be seen.
8. Center the filament image with the two coaxial centering knobs on the
lamp socket.
.. Before re-insertion of the eyepiece into the observation tube, move
your head to the right or left to ascertain that the filament image is in
center at the rear focal plane of the objective while looking into the
eyepiece tube.
If there is illumination irregularity seen in the field of view after centra.
tion of the bulb filament, loosen the clamping screw for positioning the lamp
socke~ and move the lamp sod<et back and forth slowly and clamp with the
clamping screw when even illumination is obtained.
15

60-10"
,,.,,
C. Use of Iris Diapnragms
Afield irisdiaphragm as well as an aperture
iris diaphragm
is provided on the microscope.
The field iris diaphragm
is built into the
base and the aperture iris diaphragm is part
of the condenser.
1. Field Iris Diaphragm
The field iris diaphragm controls the diam-
eter
of the ray bundle impinging on the
specimen surface and thus increases
image
definition. Stop down the field iris dia-
phragm while looking through the eyepiece.
An image of the iris diaphragm will appear
within the field. Now open the field dia-
phragm
until its diameter is just slightly
larger than the diameter
of the field of view.
•When particularly clearer
definition of
an image is required in the center of the
field
of view stop down the iris diaphragm as
narrow as shown in the picture at bottom.
•The image of the field irisdiaphragm is conjugated on the specimen's
surface,
so that the diameter of the field iris diaphragm changes
according to the change
of the objective power. By the same token
with every change of the eyepiece the field number will be varied,
which necessitates re-adjustment of the diameter at the field diaphragm.
2. Aperture Iris Diaphragm
An aperture iris diaphragm opened too
wide impairs
image con·trast due to internal
reflections
and related factors. On the
other hand,
if the diaphragm is stopped
down
exce"->5ivcly, rC50lution is unduly
reduced. It is therefore suggested to match
the opening of the aperture iris diaphragm
to the numerical aperture
of the objective
in
use, in order to achieve maximum
objective performance. For that purpose
simply set the numerical aperture scale on
the condenser
to the numerical apeflure of
the objective in use.
However, since microscopic specimens generally are low in contrast,
their image lacks contrast
if the objective is usecl with its full numerical
aperture. Therefore.
il is occasionally preferable to stop down the aperture
iris diaphragm slightly more than indicated
by the objective N.A. This
will result in increased image contrast, larger depth of focus and aflatter
field. On the other hand, stopping down
too much impairs resolution.
An aperture setting
of O.6-0.7x the N.A. of the objective is recommended.
If the N.A. of the objective is 1, for instance, you can set the scale to
0.6-0.7.
16
•
•

D. Tension Adjustment of Coarse Adjustment Knobs
While the coarse adjustment
motion is normally sliff and heavy, it is
freely adjustable for either heavy or light movemenl depending on the
observer's preference.
To adjust the tension hold lhe two coarse adiustment
knobs
with your both hands and rolate them in the opposite direction
at the same time.
E. ParfocalObjectives
Since alt objectives are par/oeal. only a
minimum of fine adJuslment control
is required when you change the objectives.
Focusing Procedure:
1) Operate the fine adjustment knob to bring the line adjustment indicator
line to the center of the fine adjustment range.
2) Place thp. lOx objective in position
3) Bring the specimen as closely as possible to the objective with the
coarse adjustment knobs.
4) While looking through the eyepiece, lower the stage slowly and focus
on the specimen.
5) Turn the revolving nosepiece to bring the objective to be used into
the light path.
F. Use of Immersion Optical Components
1. Immersion Objectives:
1) Focus on the specimen with alow-power objective.
21 Put adrop of immersion oil on both the specimen and the objective
front lens.
3) Turn the revolving nosepiece to bring the immersion objective into
the light path, and focus
with the fine adjustment knob.
2. Immersion Condensers:
1) Remove the specimen from the mechanicul stnge and place adrop of
immersion oil on the front lens of the condenser.
2) Place the specimen on the mechanical stage and slowly raise the·con-
denser until
firm contact with the underside of the specimen slide is
made. Care should be taken to prevent oil bubbles from forming in
the oil film between condenser and specimen slide.
3. After Use
Carefully wipe off the immersion oil deposited on the lens surfaces wi th
gauze moistened
with xylene.
Never
leave oil on the lens surfaces after use as oil remnants will
seriously impair the performance of the lens systems.
17

G. Oblique Illumination
The achromatic!aplanatic condenser N.A. 1.40 has
extremely high resolving power and will give the
operator satisfactory results
even when used dry.
When using objectives lOOx, the condenser should
be immersed. The condenser can be used with all
objectives from 4x and up. Oblique illumination
will further improve resolving power.
1. With oblique illumination, the resolving power
can be doubled. As against the normal (central)
illumination where the light beams are parallel
to the optical axis of the microscope, oblique
illumination provides light bundles
at an angle
to the optical ax is.
The illuminating light proceeds from below with
an inclination to the specimen, which will cause
not only the normal transmitted beam but also
more
of the refracted light to enter the objective.
This
will double the resolving power as compared
with central illumination. The drawing on the
right hand side illustrates the oblique illumina-
tion system.
The cross-hatched
area represents the cone of
light.
c
C: Optical axis
Cd: Condenser Ob:
Objective~
r: Iris diaphragm
CD Resolving power
increases in this
direction.
® Resol'Ving power
decreases in this
direction.
~s
•
.-----
---.
2. Procedure
1) Stop down the aperture iris diaphragm.
2) Loosen the clamping screw and pull out the
aperture diaphragm with the slide lever.
The direction
of diaphragm displacement
should be at right angles to the specimen
detail to be observed.
For example, jf it is desired to identify two
parallel details very close to each other as two
separate Jines, the aperture diaphragm is
moved at right angles to the details. If iden·
tification of two points is desired, the
diaphragm
is moved parallel to the straight
line.connecting the two points.
3) Adjustment of the diaphragm slide and
diaphragm diameter while
looking through
the eyepiece resolves the
two lines or points
and permits very detailed observation
of tfie
structure.
3. Observation of Overall Area Possible
OaArticle
to be identified
blique illumination
is effective only when the S~ Sliding direction of iris
illuminating
light is directed at right angles to
the specimen
In order
to identify individual specimen details, therefore, it is necessary
to adapt the direction of diaphragm displacement perpendicl:llar to
the direction
of the specimen detail to be observed.
Diaphragm
rotation through 1500 is possible with the achromatic!
aplanatic condenser.
Stage rotation provides further possibility of
directional adaptation.
18