KERN Optics OBF-1 User manual

OBF-1_OBL-1-BA-e-1510
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 OBF-1, OBL-1
OBF 121, OBF 122, OBF 123, OBF 131, OBF 132, OBF 133
OBL 125, OBL 127, OBL 135, OBL 137
Version 1.0
01/2015

OBF-1_OBL-1-BA-e-1510 2
GB
KERN OBF-1, OBL-1
Version 1.0 01/2015
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....................................................................................13
4.1 Microscope head .................................................................................................................... 13
4.2 Objectives ............................................................................................................................... 13
4.3 Eyepieces................................................................................................................................ 13
4.4 Colour filter ............................................................................................................................. 13
4.5 Condenser............................................................................................................................... 14
5Operation....................................................................................14
5.1 Getting started........................................................................................................................ 14
5.2 (Pre-) focussing ...................................................................................................................... 15
5.3 Adjusting the interpupillary distance................................................................................... 16
5.4 Dioptre adjustment................................................................................................................. 16
5.5 Adjusting the magnification.................................................................................................. 17
5.6 Adjusting the Koehler illumination....................................................................................... 18
5.7 Using eye cups ....................................................................................................................... 20
5.8 Using oil immersion objectives ............................................................................................ 21
6Changing the bulb .....................................................................22
7Changing the fuse......................................................................23
8Using optional accessories.......................................................23
8.1 Polarisation unit ..................................................................................................................... 23
8.2 Camera connection ................................................................................................................ 24
8.3 Dark field units........................................................................................................................ 24
8.4 Phase-contrast unit................................................................................................................ 25
8.5 Fluorescence reflected light unit.......................................................................................... 27
9Trouble shooting........................................................................38
10 Service........................................................................................40
11 Disposal......................................................................................40
12 Further information....................................................................40

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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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Under no circumstances should you touch the integrated halogen bulbs either during
operation or directly after use. These bulbs produce significant heat and therefore
there is a risk that the user could be severely burnt. So before handling the bulbs,
you must check that they have cooled down.
The microscope housing, on the other hand, is constructed so that no significant heat
radiation emanates from the device and that there is absolutely no risk of the user
burning themselves from the housing outer surfaces.
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
Microscope head / Tube
Adjusting screw
Head
Nosepiece
Objective
Object holder
Specimen stage
Aperture adjustment
Condenser
Condenser
Field lens with
Field diaphragm
Control dial
X –Y axis
Specimen
stage
Fine
adjustment
knob
Dimmer
Coarse
adjustment
knob
Lens barrel

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Rear view
Adjusting ring
torque
Carrying
handle
Main switch
Power
connection
Coarse
adjustment
knob
Fine
adjustment
knob
Fuse
Condenser
Focus dial
Adjusting ring
torque

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3 Technical data / Features
Model
KERN
Standard configuration
Optical system
Tube
Illumination
OBF 121
Finite
Binocular
6V / 20W Halogen (Transmitted light)
OBF 122
Finite
Binocular
6V / 20W Halogen (Transmitted light)
OBF 123
Finite
Binocular
3W LED (Transmitted light)
OBF 131
Finite
Trinocular
6V / 20W Halogen (Transmitted light)
OBF 132
Finite
Trinocular
6V / 20W Halogen (Transmitted light)
OBF 133
Finite
Trinocular
3W LED (Transmitted light)
OBL 125
Infinity
Binocular
6V / 20W Halogen (Transmitted light)
OBL 127
Infinity
Binocular
3W LED (Transmitted light)
OBL 135
Infinity
Trinocular
6V / 20W Halogen (Transmitted light)
OBL 137
Infinity
Trinocular
3W LED (Transmitted light)
Eyepieces OBF-1:
Eyepieces OBL-1:
WF 10x / Ø 18 mm
WF 10x / Ø 20 mm
Objectives:
4x / 10x / 40x / 100x
Product dimensions:
395x200x380 mm
Packaging dimensions:
400x280x435 mm
Net weight:
6,7 kg
Gross weight:
8 kg
Input voltage:
AC 100-240V, 50-60Hz
Output voltage:
DC 1,2-6V
Fuse:
2A 5x20mm

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4 Assembly
4.1 Microscope head
Inside the packaging the microscope head is already mounted but inclined towards
the rear. In order to turn it to the front you must loosen the fixing screw on the tube
connection point and after the turning fix it again with the screw. In case of removing
the head completely from the housing, you should always make sure that you do not
touch the lenses with your bare fingers and that no dust enters the apertures.
4.2 Objectives
All 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 simply placed onto the tube connectors, once you have first removed the plastic
protective caps. There is no way of fixing them. 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 Colour filter
A blue colour filter is already an integral part of the microscopes of the series OBF-1
and OBL-1. It is fitted underneath the field diaphragm. In order to use suitable filters,
these can simply be placed in the ring bracket of the field lens.

OBF-1_OBL-1-BA-e-1510 14
4.5 Condenser
We recommend that you use the course adjustment knob to bring the specimen
stage to its uppermost position. Use the focus dial of the condenser to move the
condenser holder to the central position. In this way the condenser can be fitted at
the right place in the condenser holder and fixed with the adjusting screw. When
doing this, you should be able to read the scale from the front. You should avoid
touching the optical lenses with bare fingers.
5 Operation
5.1 Getting started
The very first step is to establish a power connection using the mains plug. 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. You can now switch on the lighting using the main switch.
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 a total of two object holders at the same time.

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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
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
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.

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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 Koehler 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. If,
as with the devices in the KERN OBF-1 and OBL-1 series, the lighting can be set in
accordance with Koehler, the result is homogenous illumination of the slide and
avoidance of disruptive stray light.
The necessary control elements for this are:
Height-adjustable and centre-adjustable condenser with aperture diaphragm
Field diaphragm
Note: The condenser of the microscopes of the series OBF-1 and OBL-1 is not
centre-adjustable. Therefore it is not a full Koehler illumination. However this is
regarded as Fixed-Koehler, since the condenser is pre-centred.
When adjusting the Koehler lighting for the first time, you must first select the lowest
possible objective magnification, so that you can carry out the following steps.
1. Use the condenser focus wheel to position the condenser
directly below the specimen stage. Switch on the lighting
and use the coarse and fine adjustment knob to bring the
slide with the cover glass positioned facing upwards into
focus.
2. Close the field diaphragm completely using its adjusting
ring. When you look in the microscope a blurred image
appears in the aperture.
3. Adjust the height of the condenser until the image from the
field diaphragm appears clearly in the field of view. For
some microscopes there is a risk that you will lift the
condenser up so high that it collides with the object holder.
Therefore care is needed when doing this.

19 OBF-1_OBL-1-BA-e-1510
4. Open the field diaphragm until it just disappears out of the
field of view.
If necessary, simply re-centre using the centring screws on
the condenser holder.
5. Use the aperture diaphragm of the condenser to find the
very best compromise between contrast and resolution for
the microscopic image. The scale divisions on the
condenser can be used as a guideline. Select in
accordance with the objective being used.
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.
6. It is possible to alter the brightness of the bulb using the dimmer. The brightness
is always controlled by the bulb brightness and not by the aperture diaphragm.
7. Possibly there is the need of re-adjusting the focus and x-y axis.
8. Observe the object.
If another magnification is selected afterwards, then the Koehler illumination does not
have to be reset from scratch, only the aperture diaphragm and field diaphragm need
to be adjusted as required.