KERN Optics OBE 121 User manual

OBE-12_13-BA-e-2020
KERN & Sohn GmbH
Ziegelei 1
D-72336 Balingen
E-Mail: [email protected]
Tel: +49-[0]7433- 9933-0
Fax: +49-[0]7433-9933-149
Internet: www.kern-sohn.com
User instructions
Transmitted light laboratory microscope
KERN OBE-1
OBE 121, OBE 122, OBE 124
OBE 131, OBE 132, OBE 134
Version 1.0
01/2020

OBE-12_13-BA-e-2020 2
GB
KERN OBE-1
Version 1.0 01/2020
User instructions
Transmitted light microscope
Table of contents
1Before use....................................................................................3
1.1 General notes............................................................................................................................ 3
1.2 Notes on the electrical system................................................................................................ 3
1.3 Storage ...................................................................................................................................... 4
1.4 Maintenance and cleaning....................................................................................................... 5
2Nomenclature...............................................................................6
3Technical data / Features ............................................................8
4Assembly....................................................................................10
4.1 Microscope head .................................................................................................................... 10
4.2 Objectives ............................................................................................................................... 10
4.3 Eyepieces................................................................................................................................ 10
4.4 Condenser............................................................................................................................... 10
5Operation....................................................................................11
5.1 Getting started........................................................................................................................ 11
5.2 (Pre-) focussing ...................................................................................................................... 12
5.3 Adjusting the interpupillary distance................................................................................... 13
5.4 Dioptre adjustment................................................................................................................. 13
5.5 Adjusting the magnification.................................................................................................. 14
5.6 Adjusting the illumination ..................................................................................................... 15
5.7 Using eye cups ....................................................................................................................... 16
5.8 Using oil immersion objectives ............................................................................................ 17
6Changing the bulb .....................................................................17
7Using optional accessories.......................................................18
7.1 Dark field unit.......................................................................................................................... 18
7.2 Camera connection ................................................................................................................ 18
8Trouble shooting........................................................................19
9Service........................................................................................21
10 Disposal......................................................................................21
11 Further information....................................................................21

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1 Before use
1.1 General notes
You must open the packaging carefully, to make sure that none of the accessories in
the packaging fall on the floor and get broken.
In general, microscopes should always be handled carefully because they are
sensitive precision instruments. When using or transporting the microscope it is
particularly important to avoid abrupt movements, as this may damage the optical
components.
You should also avoid getting dirt or finger prints on the lens surface, because in
most cases this will reduce image clarity.
To maintain the performance of the microscope, it must never be disassembled. So
components such as lenses and other optical elements should be left as they were
before use. Also the electrical parts on the rear and base of the device must not be
tampered with, as in this area there is an additional risk of triggering an electric
shock.
1.2 Notes on the electrical system
Before connecting to a mains power supply, you must make sure that you are using
the correct input voltage. The information to select the correct mains cable is located
on the device, on the rear of the product directly above the connection socket. You
must comply with this information. If you do not comply with these specifications, then
fires or other damage to the device could occur.
The main switch must also be switched off before the mains cable is connected. In
this way you will avoid triggering an electric shock.
If you are using an extension cable, then the mains cable you use must be earthed.
If the original fuse should blow, it must only be replaced by an appropriate fuse.
Suitable replacement fuses are included with the delivery.
When carrying out any procedures whereby you come into contact with the electrical
system of the device, such as, for example, changing the bulb or fuse, only carry out
these procedures when the power is disconnected.

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1.3 Storage
You should ensure that the device is not exposed to direct sunlight, temperatures
which are too high or too low, vibrations, dust or a high level of humidity.
The ideal temperature range is between 0 and 40°C and a relative humidity of 85%
should not be exceeded.
The device should always be located on a rigid, smooth, horizontal surface.
When the microscope is not being used, you should cover it with the enclosed dust
protective cover. When doing this, the power supply is stopped by switching off at the
main switch and unplugging the mains cable. If the eyepieces are being stored
separately, the protective caps must be fitted to the tube connectors. In most cases,
if dust and dirt gets inside the optical unit of a microscope this can cause irreversible
errors or damage.
The best way to store accessories which consist of optical elements, such as, for
example, eyepieces and objectives, is in a dry box with desiccant.

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1.4 Maintenance and cleaning
In any event, the device must be kept clean and dusted regularly.
If any moisture should be occur, before you wipe down the device you must ensure
that the mains power is switched off.
When glass components become dirty, the best way to clean them is to wipe them
gently with a lint-free cloth.
To wipe oil stains or finger prints off the lens surface, moisten the lint free cloth with a
mixture of ether and alcohol (70 / 30 ratio) and use this to clean the lens.
You must be careful when handling ether and alcohol, as these are highly flammable
substances. You must therefore keep it away from naked flames and electrical
devices which can be switched on and off, and only use it in well-ventilated rooms.
However organic solutions of this type should not be used to clean other components
of the device. This could lead to damage to the paint finish. To do this, it is sufficient
to use a neutral cleaning product.
You could also use the following cleaning products to clean the optical components:
Special cleaner for optical lenses
Special optical cleaning cloths
Bellows
Brush
When handled correctly and checked regularly, the microscope should give many
years of efficient service.
Should repairs still be necessary, please contact your KERN dealer or our Technical
Department.

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2 Nomenclature
Eyepiece
Lens barrel
Camera adapter
connection
Microscope head /
Tube
Nosepiece
Objective
Object holder
Specimen stage
Condenser
Control dial
X –Y axis
Specimen
stage
Fine
adjustment
knob
Field lens
Dimmer
+
Main switch
Coarse
adjustment
knob

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Power connection

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3 Technical data / Features
Model
KERN
Standard configuration
Optical
system
Tube
Eye pieces
Objectives
Illumination
OBE 121
Finite
Monocular
WF 10x / Ø 18 mm
Achromatic
4x/10x/40x
3W LED (Transmitted)
OBE 122
Finite
Binocular
WF 10x / Ø 18 mm
Achromatic
4x/10x/40x
3W LED (Transmitted)
OBE 124
Finite
Trinocular
WF 10x / Ø 18 mm
Achromatic
4x/10x/40x
3W LED (Transmitted)
OBE 131
Finite
Monocular
WF 10x / Ø 18 mm
Achromatic
4x/10x/40x/100x
3W LED (Transmitted)
OBE 132
Finite
Binocular
WF 10x / Ø 18 mm
Achromatic
4x/10x/40x/100x
3W LED (Transmitted)
OBE 134
Finite
Trinocular
WF 10x / Ø 18 mm
Achromatic
4x/10x/40x/100x
3W LED (Transmitted)
Product dimensions:
360x150x320 mm
Packaging dimensions:
425x340x245 mm
Net weight:
4,6 kg
Gross weight:
6 kg
Input current:
AC 100-240V, 50-60Hz, 0,3A
Output current:
DC 5V, 1,0A

9 OBE-12_13-BA-e-2020

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4 Assembly
4.1 Microscope head
The microscope head is firmly attached at the microscope body and cannot be
removed.
However thanks to the butterfly design the tube is rotatable by 360°, which enables a
flexible adjustment of the eyepieces
4.2 Objectives
Depending on the model all three or four objectives are already mounted to the
nosepiece. After removing the protective foil they are ready for use. They are ranged
in such a way that if you turn the nosepiece clockwise, the objective with the next
higher magnification appears. When the objectives need to be dismounted, you
should always make sure that you do not touch the lenses with your bare fingers and
that no dust enters the apertures.
For objectives which are marked “OIL”, you must use an immersion oil with the
lowest level of inherent fluorescence.
4.3 Eyepieces
You must always use eyepieces with the same magnification for both eyes. These
are already placed onto the tube connectors and each is fixed with a small silver
screw under the eyepiece on the tube connectors, so that they are turnable but you
cannot pull them out of the tube. When changing the eyepieces, you must loosen
these screws and once the new eyepiece is fitted, then they must be re-tightened.
You should always make sure that you do not touch the lenses with your bare fingers
and that no dust enters the apertures.
4.4 Condenser
The condenser is firmly fixed onto a holding ring (condenser holder) underneath the
microscope stage. The lever for the aperture diaphragm is directed towards the front.
There is the ability to adjust the height of the condenser, but not to centre it.
The height adjustment of the condenser is done by turning the condenser on
its vertical axis.
You should avoid touching the optical lenses with bare fingers.

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5 Operation
5.1 Getting started
The very first step is to establish a power connection using the mains plug. After
switching on the lighting you should first adjust the dimmer to a low level, so that
when you look through the eyepiece for the first time, your eyes are not immediately
subject to a high level of light.
The next step is to place an object holder with the sample on the angle table. To do
this, the cover glass must be facing upwards. You can fix the object holder to the
table using the slide holder (see illustration on the left). To move the sample into the
beam path, you must use the adjustment wheels on the right of the angle table (see
illustration on the right).
You can position only one object holder.

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5.2 (Pre-) focussing
When you are observing an object, you must have the correct distance to the
objective to achieve a sharp image.
In order to find this distance at the beginning (without other default settings of the
microscope) place the objective with the lowest magnification in the beam path, look
through the right eyepiece with the right eye and turn it slowly using the coarse
adjustment knob (see illustration).
The simplest way of doing this would be to first raise the specimen stage (using the
coarse adjustment knob) until it is just under the objective and then lower it slowly. As
soon as an image is recognisable (no matter how sharp), then you should only adjust
the focus using the fine adjustment knob.
Adjusting the torque of the coarse and fine adjustment knob
Next to the left adjustment wheel for the coarse and fine adjustment knob there is a
ring which you can use to alter the torque of these wheels. Turning it in a clockwise
direction reduces the torque and turning it in an anti-clockwise direction increases it.
On one hand, this function can help to make it easier to adjust the focus and on the
other hand it can prevent the specimen stage from slipping down unintentionally.
Important:
In order to avoid damaging to the focussing system, the left and right adjustment
wheels for the coarse and fine adjustment knob must never be rotated at the same
time in opposite directions.

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5.3 Adjusting the interpupillary distance
(For binocular and trinocular devices)
With binocular viewing, the interpupillary distance
must be adjusted accurately for each user, in
order to achieve a clear image of the object.
While you are looking through the eyepieces, use
your hands to hold the righthand and lefthand tube
housing firmly. By pulling them apart or pushing
them together, you can either increase or reduce
the interpupillary distance (see illustration). As
soon as the field of views of the lefthand and
righthand eyepieces completely overlap each
other, i.e. they combine to form a circular image, then the interpupillary distance is
set correctly.
5.4 Dioptre adjustment
(For binocular and trinocular devices)
The eye strengths of each eye of the microscope user can often be slightly different,
which in daily life has no consequences. But when using a microscope this can
cause problems in achieving precise focussing.
You can use a mechanism on the left tube connector (dioptre adjustment ring) to
compensate for this as follows.
1. Look through the right eyepiece with the right eye and bring the object into focus
by using the coarse and fine adjustment knob.
2. Then look through the left eyepiece with the left eye and use the dioptre
adjustment ring to focus the image.
To do this, you just need to turn the ring in both directions (see illustration), to find
out where the image is at its most focussed.

OBE-12_13-BA-e-2020 14
5.5 Adjusting the magnification
After prefocussing has been carried out using the objective with the lowest
magnification (see section 5.2), you can then adjust the overall magnification using
the nosepiece, as necessary. By turning the nosepiece you can bring any one of the
four other objectives into the beam path.
When adjusting the nosepiece, you must take the following points into account:
- The required objective must be properly locked in
place at all times.
- The nosepiece should not be rotated by holding
individual objectives, you should use the silver
ring above the objectives (see illustration).
- When rotating the nosepiece you must always make sure that the objective which
is about to be positioned in the beam path does not touch the object holder. This
can lead to significant damage to the objective lens.
We recommend that you always check from the side to make sure that there is
sufficient leeway. If this should not be the case, the specimen stage must be
lowered accordingly.
If you have focussed the object to be observed for a specific magnification, then if
you select the objective with the next greatest magnification, then the object will be
slightly out of focus. Use the fine adjustment knob to make a slight adjustment and
restore the focus.

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5.6 Adjusting the illumination
To make sure that perfect image results are achieved during microscopic
observation, it is important that the direction of light of the microscope is optimised.
The necessary control elements for this are the height-adjustable condenser with
aperture diaphragm.
When adjusting the lighting for the first time, you must first select the lowest possible
objective magnification, so that you can carry out the following steps.
1. Adjust the height of the condenser by turning the condenser to get a good
contrast of the microscopic image. Normally therefore you have to bring the
condenser to just below the maximum height.
2. Use the aperture diaphragm of the condenser to find the
very best compromise between contrast and resolution for
the microscopic image. For the objective with the lowest
magnification the lever of the aperture diaphragm should
be placed almost completely on the right-side limit, so that
the opening of the diaphragm is very small. The higher the
magnification of an objective, the larger the opening should
be selected by pushing the lever towards the left-side limit.
The view in the tube without the eyepiece should look
something like the illustration on the right.
The diameter of the aperture diaphragm which is then visible should make up
approximately 2/3 of the pupil diameter.
If the eyepiece should be removed, for checking, then please make sure that no
dirt or dust falls into the tube.
3. The brightness is always controlled by the bulb brightness (using the dimmer) and
not by the aperture diaphragm.

OBE-12_13-BA-e-2020 16
5.7 Using eye cups
The eye cups supplied with the microscope can basically be used at all times, as
they screen out intrusive light, which is reflected from light sources from the
environment onto the eyepiece, and the result is better image quality.
But primarily, if eyepieces with a high eye point (particularly suitable for those who
wear glasses) are used, then it may also be useful for users who don’t wear glasses,
to fit the eye cups to the eyepieces.
These special eyepieces are also called High Eye Point eyepieces. They can be
identified by the glasses symbol on the side. They are also marked in the item
description by an additional “H” (example: HSWF 10x Ø 23 mm).
When fitting the eye cups, make sure that the dioptre setting is not moved. We would
therefore advise that you hold the dioptre compensation ring on an eyepiece with one
hand while you fit the eye cup with the other.
Before using the microscope, users who wear glasses must remove the eye cups,
which you may find on High Eye Point eyepieces.
As the eye cups are made of rubber, you must be aware that when you are using
them, they can become slightly dirty through grease residues. In order to maintain
hygiene, we would therefore recommend that you clean the eye cups regularly (e.g.
with a damp cloth).
Eye cups
High Eye Point eyepiece
(identified by the glasses symbol)

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5.8 Using oil immersion objectives
The 100x objectives of the OBE-13 series are objectives which can be used with oil
immersion (they are always marked with the word “OIL”). Using these generates a
particularly high resolution for microscopic images.
To use oil immersion correctly, please follow these steps.
1. Put a drop of oil on the cover glass (with standard thickness of 0.17 mm) of the
object slide.
2. Lower the specimen stage and position the 100x objective in the beam path.
3. Bring the specimen stage or object slide to the objective very slowly until there is
slight contact.
4. Observe the object.
The object slide and objective must not be pressed against each other. The oil
constitutes the contact layer.
If the contact is made too jerky, there is a chance that existing air bubbles in the oil
cannot escape. This would have a negative impact on image clarity.
After use or before changing the slide, any components which have been in contact
with the oil must be cleaned thoroughly. See also 1.4 Maintenance and cleaning.
6 Changing the bulb
The devices in the OBE-12 and OBE-13 ranges with lighting are all fitted with LED
bulbs.
Due to the long service life of an LED lighting system, for these microscopes it will
not be necessary to simply change a bulb.
Problems with the lighting unit would therefore, in most cases, be caused by defects
in the electrical system. If this is the case, then our Technical Service will be able to
help.

OBE-12_13-BA-e-2020 18
7 Using optional accessories
7.1 Dark field unit
There is the following way to carry out dark field applications.
1. A dark field attachment with an integrated black disk can be
screwed into the standard condenser of the microscope from
below (see right illustration). Please take note of the
instruction delivered with the dark field attachment.
7.2 Camera connection
OBE 124, OBE 134
Due to the trinocular tube, which is a standard fitting for the models OBE 124 and
OBE 134, it is possible to connect microscope cameras to the device, in order to
digitally record images or sequences of images of an object being observed.
After the plastic cover has been removed from the camera adapter connector on the
top of the microscope head, then a suitable adapter must be fitted.
In general there are two C-mount adapters available for this (1x and 0.5x
magnification, see Chapter 3 Features). After fitting one of these adapters it can be
fixed with the fixing screw. A camera which has a C-mount thread is then screwed on
top of the adapter.
We recommend that you first adjust the field of view using the eyepieces on the
device for the existing requirements, and then carry out the observation using the
microscope camera (i.e. using the PC screen which is connected).
The tube has a light distribution that guarantees the providing of light for the
eyepieces and the camera connection at the same time. This means that it is
possible to simultaneously observe by the eyepieces and PC screen.
For C-mount adapters, which have their own integrated magnification, the image
which is shown on the camera connected to the device can often have a different
level of focus compared with the image on the eyepiece.
In order to be able to bring both images into focus, the focus can be adjusted by
those adapters.

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8 Trouble shooting
Problem
Possible causes
The bulb does not light
The mains plug is not correctly plugged in
There is no power at the socket
Defective bulb
The field of view is dark
The aperture diaphragm and/or field
diaphragm are not opened wide enough
The condenser is not correctly centred
You cannot adjust the brightness
The brightness control has been set
incorrectly
The condenser has not been correctly
centred
The condenser is too low
The field of view is dark or is not
correctly
illuminated
The objective is not positioned correctly on
the beam path
The nosepiece is not correctly fitted
The condenser is not correctly fitted
An objective is being used which doesn’t
match the lighting area of the condenser
The condenser has not been correctly
centred
The bulb is not correctly fitted
The field of view of one eye does not
match that of the other eye
The interpupillary distance is not correctly
adjusted
Dioptre setting has not been carried out
correctly
Different eyepieces are used for the
righthand and lefthand side
The eyes are not used to using a microscope