KERN OPTICS OKO-1 User manual

OKO-1-BA-en-2111
KERN & Sohn GmbH
Ziegelei 1
D-72336 Balingen
Email: [e-mail]
Tel: +49-[0]7433- 9933-0
Fax: +49-[0]7433-9933-149
Internet: www.kern-sohn.com
Operating instructions
Metallurgical microscope
KERN OKO-1
OKO 178
Version 1.1
01/2021

OKO-1-BA-en-2111 2
EN
KERN OKO-1
Version 1.1 01/2021
Operating instructions
Metallurgical microscope
Table of Contents
1Before use......................................................................................3
1.1 General information ................................................................................................................. 3
1.2 Notes on the electrical system................................................................................................ 3
1.3 Storage ...................................................................................................................................... 4
1.4 Maintenance and cleaning....................................................................................................... 5
2Nomenclature ................................................................................6
3Technical data / equipment ..........................................................9
4Assembly .....................................................................................11
4.1 Incident light unit.................................................................................................................... 12
4.2 Microscope head .................................................................................................................... 12
4.3 Objective ................................................................................................................................. 12
4.4 Eyepieces ................................................................................................................................ 13
4.5 Color filter ............................................................................................................................... 13
4.6 Condenser............................................................................................................................... 13
5Operation .....................................................................................14
5.1 First steps ............................................................................................................................... 14
5.2 (Pre-) Focusing ....................................................................................................................... 15
5.3 Adjusting the eye relief.......................................................................................................... 16
5.4 Diopter compensation............................................................................................................ 16
5.5 Setting the magnification ...................................................................................................... 17
5.6 Using the eyecups.................................................................................................................. 18
5.7 Adjustment of Köhler illumination for transmitted light .................................................... 19
5.8 Adjustment of the illumination for incident light ................................................................ 22
6Lamp replacement ......................................................................23
7Fuse replacement........................................................................23
8Use of optional accessories.......................................................24
8.1 Polarization unit (transmitted light)...................................................................................... 24
8.2 Camera connection ................................................................................................................ 25
9Troubleshooting..........................................................................26
10 Service .........................................................................................28
11 Disposal .......................................................................................28
12 Further information.....................................................................28

3 OKO-1-BA-en-2111
1 Before use
1.1 General information
The packaging must be opened carefully to prevent the accessories inside from falling
to the floor and breaking.
In general, a microscope should always be handled with great care, as it is a sensitive
precision instrument. Avoiding abrupt movements during operation or transport is
therefore particularly important, especially in order not to endanger the optical
components.
Likewise, you should avoid dirt or fingerprints on the lens surfaces, as this will reduce
image clarity in most cases.
If the performance of the microscope is to be maintained, it must never be
disassembled. Components such as objective lenses and other optical elements
should therefore be left as they are found at the start of operation. Also the electrical
part at the back and at the bottom of the instrument must not be tampered with without
further ado, because here there is the additional danger of triggering an electric shock.
1.2 Notes on the electrical system
Before connecting to a power supply, be sure to use the correct input voltage. The
power cord selection guide is located on the back of the unit, just above the power
jack. Failure to follow these instructions may result in fire or other damage to the unit.
Also, the main power switch should be turned off before connecting the power cord.
This will prevent an electric shock from occurring.
If you use an extension cord, the power cord you use must be grounded.
If the original fuse blows, replace it only with a suitable fuse. Suitable replacement
fuses are included in the scope of delivery.
All handling of the equipment that involves contact with the electrical system, such as
changing lamps or fuses, may only be carried out when the power supply is
disconnected.

OKO-1-BA-en-2111 4
1.3 Storage
Avoid exposing the device to direct sunlight, high or low temperatures, shock, dust and
high humidity.
The suitable temperature range is 0 - 40° C and a relative humidity of 85 % should not
be exceeded.
The device should always be placed on a firm, smooth and horizontal surface.
When the microscope is not in use, it is best to cover it with the dust cover provided.
The power supply should be switched off at the main switch and the power cord
removed. When storing the eyepieces separately, it is essential to attach the protective
caps to the tube sockets. Dust or dirt inside the optics of a microscope can in many
cases cause irreversible malfunctions or damage.
Accessories consisting of optical elements, such as eyepieces and objectives, are
preferably stored in a drying box with desiccant.

5 OKO-1-BA-en-2111
1.4 Maintenance and cleaning
In any case, the device must be kept clean and regularly cleaned of dust.
Before wiping down the unit when wet, make sure that the power is turned off.
Glass components should preferably be wiped lightly with a lint-free cloth when
contaminated.
To wipe off oil stains or fingerprints from lens surfaces, the lint-free cloth is moistened
with a mixture of ether and alcohol (ratio 70 / 30) and then used for cleaning.
Ether and alcohol must always be handled with care as they are highly flammable
substances. Therefore, it is essential to keep them away from open flames and
electrical appliances, which are switched on and off, and use only in well-ventilated
rooms.
However, organic solutions of this type should not be used to clean other components
of the device. This could result in changes to the paintwork. It is sufficient to use a
neutral cleaning agent for this purpose.
Other cleaning agents for the optical components include:
•Special cleaner for optical lenses
•Special optical cleaning cloths
•Bellows
•Brush
With proper handling and regular inspection, the microscope will operate smoothly for
many years.
However, if a repair is necessary, contact your KERN dealer or our Technical Service.

OKO-1-BA-en-2111 6
2 Nomenclature
Eyepieces
Camera adapter
connector
Microscope head / tube
Locking screw/
Microscope head
LED incident
light unit
Dial X - Y axis
Object table
Dimmer
Coarse and
fine drive
Locking screw
Condenser
Field lens with
field diaphragm
Centering screw
Condenser
Condenser with
aperture adjustment
Object table
Object holder
Lens
Objective
nosepiece

7 OKO-1-BA-en-2111
Rear view
Carrying
handle
Coarse and fine
drive
Main switch
Mains
connection
Fuse
LED incident light
unit
Power cable
for incident

OKO-1-BA-en-2111 8
Incident light unit
Insertion for diffuser
Luminous field
diaphragm
Lamp housing
Colour filter
Polariser
Analyser
Aperture diaphragm

9 OKO-1-BA-en-2111
3 Technical data / equipment
Dimensions Product:
550x200x460 mm
Dimensions Packing:
520x470x430 mm
Net weight:
12 kg
Gross weight:
16 kg
Input voltage:
AC 100-240V, 50-60Hz
Output voltage:
DC 1.2-6V
Fuse:
2A 5x20mm

OKO-1-BA-en-2111 10

11 OKO-1-BA-en-2111
4 Assembly

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4.1 Incident light unit
First, the lamp housing and the incident light unit must be brought together at their
connection points. Then the connection is fixed via an Allen screw on the right at the
connection point of the lamp housing.
Analyzer, polarizer and color filter slides can now be placed in the appropriate slots
(see page 8).
To subsequently attach the incident light unit to the microscope, first loosen the
fastening screw at the tube connection point and remove the black protective cover.
The round dovetail mount on the incident light unit can now be inserted into the round
dovetail mount on the housing and fixed with the fixing screw. Always make sure that
the lenses are not touched with bare fingers and that no dust enters the openings.
Finally, the power cable must be used to make the connection between the lamp
housing and the connection socket on the back of the microscope.
4.2 Microscope head
First loosen the fixing screw at the connection point of the incident light unit and remove
the black protective cover.
The round dovetail mount on the head can now be inserted into the round dovetail
mount on the incident light unit and fixed with the fixing screw. Always make sure that
the lenses are not touched with bare fingers and that no dust enters the openings.
4.3 Objective
The stage must be in the lower position so that the objectives can be screwed into the
revolving nosepiece. The objectives can now be screwed into the revolving nosepiece
in such a way that the objective with the next higher magnification appears when the
revolving nosepiece is turned clockwise. Care should be taken not to touch the lenses
with bare fingers and not to allow dust to enter the apertures.

13 OKO-1-BA-en-2111
4.4 Eyepieces
Always use eyepieces with the same magnification for both eyes. These are simply
placed on the tube sockets after first removing the protective plastic caps. There is no
fixation possibility. You should always make sure that the lenses are not touched with
your bare fingers and that no dust enters the openings.
4.5 Color filter
A blue color filter is already part of the condenser. It is screwed to the bottom of the
condenser by means of a ring holder. It can be removed at any time. To use suitable
filters without this retaining ring, they can simply be placed in the ring holder of the field
lens.
4.6 Condenser
The object stage should best be brought into the uppermost position using the coarse
drive. With the focus wheel of the condenser one must now bring the condenser carrier
into a middle position. This way, the condenser can be inserted into the condenser
carrier at the appropriate position and fixed with the locking screw. The scale should
be readable from the front. Avoid touching the optical lenses with your bare fingers.
For items 7 (polarizing unit) and 8 (camera connector), see Chapter 8 Using
Optional Accessories.

OKO-1-BA-en-2111 14
5 Operation
5.1 First steps
The first thing to do is to connect the power supply by means of a mains plug. The
light intensity control (dimmer) should first be set to a low level, so that the eyes
are not immediately exposed to too much light when looking into the eyepieces for the
first time. Now the illumination can be switched on via the main switch.
The next step is to place an object or slide with specimen on the stage. The cover
glass (if used) must face upwards for this.
In order to move the point of the object to be observed into the beam path, the
adjustment wheels on the right of the mechanical stage must be operated accordingly
(see illustration).

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5.2 (Pre-) Focusing
In order for an object to be observed, it must be at the correct distance from the lens
so that a sharp image can be obtained.
To find this distance initially (without any other presettings of the microscope), bring
the objective with the lowest magnification into the beam path, look with the right eye
through the right eyepiece and turn the coarse adjustment knob slowly at first (see
illustration).
The simplest method for this would be to bring the stage (also using the coarse drive)
to just below the lens beforehand and then slowly lower it. As soon as an image (no
matter how sharp) can then be seen, the correct sharpness should only be set with the
fine drive.
Torque adjustment of coarse and fine drive
Next to the left adjusting wheels of the coarse and fine drive is a ring which can be
used to change the torque of these wheels. Turning clockwise decreases the torque
and turning counterclockwise increases the torque.
This function can be used to facilitate the focus adjustment on the one hand and to
prevent the object stage from sliding down unintentionally on the other hand.
Important
To avoid damage to the focusing system, never turn the left and right dials of the coarse
and fine focus knobs in opposite directions at the same time.

OKO-1-BA-en-2111 16
5.3 Adjusting the eye relief
In binocular viewing, the interpupillary distance
must be precisely adjusted for each user to obtain
a clear image of the object.
While looking through the eyepieces, hold the left
and right tube housings with one hand each. By
pulling them apart or pushing them together, the
interpupillary distance can be either increased or
decreased (see illustration). As soon as the field of
view of the left eyepiece and the field of view of the
right eyepiece overlap completely, or merge into a
single circular image, the correct interpupillary distance has been set.
5.4 Diopter compensation
The visual acuity of the eyes of a person using the microscope can very often show
minor differences, which are inconsequential in everyday life, but can cause problems
with regard to exact focusing when using the microscope.
A mechanism on the two eyepieces (diopter compensation rings) can be used to
compensate for this difference as follows.
1. Move right diopter adjustment ring to position 0.
2. Look through the right eyepiece with the right eye and focus the image using the
coarse and fine focus adjustment knobs.
3. Now look through the left eyepiece with the left eye and focus the image using the
left diopter compensation ring.
To do this, turn the ring in both directions (see illustration) to find out at which
position the image appears sharpest.

17 OKO-1-BA-en-2111
5.5 Setting the magnification
After pre-focusing using the objective with the lowest magnification (see section 5.2),
the total magnification can now be adjusted as required using the revolving nosepiece.
By rotating the revolver, any of the four other objectives can be brought into the beam
path.
It is essential to observe the following points when adjusting the revolving nosepiece:
- The desired lens must always be properly
engaged.
- The turret should not be rotated by holding it by
the individual lenses, but by the silver ring above
the lenses (see illustration).
- When rotating the turret, always make sure that the objective lens that is being
brought into the beam path does not come into contact with the specimen slide.
This can cause considerable damage to the objective lens.
It is best to always check from the side whether there is sufficient clearance. If this
is not the case, the object table must be lowered accordingly.
If you have focused the object of observation for a certain magnification, the focus can
easily get out of focus when selecting the objective with the next higher magnification.
In this case, the focus must be restored by slightly adjusting the fine adjustment knob.

OKO-1-BA-en-2111 18
5.6 Using the eyecups
The eyecups included in the scope of delivery can basically always be used, as they
shield disturbing light that is reflected from light sources in the surroundings at the
eyepiece, thus resulting in better image quality.
But mainly, if eyepieces with a high viewpoint (especially suitable for eyeglass wearers)
are used, then it can be useful for users without glasses to attach the eyecups to the
eyepieces.
These special eyepieces are also called High Eye Point eyepieces and can be
recognized by a glasses symbol on the side. They are also identified by an additional
"H" in the article description (example: HSWF 10x Ø 23 mm).
With the OKO-1 series, the eyecups are already attached to the eyepiece. To use
them, simply unfold the folded rubber parts.
When unfolding the eyecups, care should be taken not to adjust the diopter setting.
Therefore, it is recommended to hold the diopter adjustment ring of an eyepiece with
one hand while unfolding the eyecup with the other.
Eyeglass wearers must fold in the eyecups before observing if there are any on the
High Eye Point eyepieces.
Since the eyecups are made of rubber, it is important to note that they can easily
become contaminated by grease residues during use. To maintain hygiene at all times,
it is therefore recommended to clean the eyecups regularly (e.g. with a damp cloth).
Eyecups
High Eye Point Eyepiece
(recognizable by the glasses symbol)

19 OKO-1-BA-en-2111
5.7 Adjustment of Köhler illumination for transmitted light
In order to obtain perfect image results during microscopic observation, it is important
that the light guidance of the microscope is optimized. If illumination can be adjusted
according to Köhler, this results in homogeneous illumination of the specimen and the
reduction of disturbing stray light.
Necessary control elements for this are:
•Height adjustable and centerable condenser with aperture diaphragm
•Illuminated field diaphragm
For the first adjustment of Köhler's illumination, the smallest possible objective
magnification must first be selected so that the following steps can then be carried out.
1. Move the condenser with the condenser focus wheel to a
position directly under the specimen stage. Switch on the
illumination and focus the specimen, which is placed with
the cover glass facing upwards, using the coarse and fine
adjustment knobs.
2. Close the field diaphragm completely at its adjustment ring.
When looking into the microscope, a blurred image of the
aperture appears. If the microscopic image becomes
completely dark, the image of the field diaphragm is
outside the field of view and must be brought into the field
of view by the centering screws of the condenser.