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Levenhuk MED 45 Microscopes
EN
General Information
Read the user manual carefully before you start working with a microscope. Levenhuk MED Series biological microscopes are
safe for health, life and property of the consumer and the environment when properly used, and meets the requirements
of international standards. These microscopes are designed for observing transparent objects in the transmitted light using
the phase contrast as well as the bright and dark field method. They perform well in clinical research and tests; teaching
demonstrations; bacterioscopy and cytology in medical and health establishments, laboratories, universities; and may be used
for scientific research in agriculture and microbiology.
Microscope assembly
•
Unpack the microscope carefully and place it on a flat surface.
• Remove the plastic bags and dustproof cover of the eyepiece head.
• Install the binocular or trinocular head and tighten the locking screw.
•
Inspect all the items included in the kit and define their purpose.
• Connect the power cord to the microscope and plug it in.
Microscope use: The bright-field method
Please refer to the fig. 1а (binocular model) and fig. 1b (trinocular model).
• Turn on the power and the illumination will turn on. Set the brightness at approximately 70%. Place the specimen on the
stage. Make sure the clips hold the specimen firmly in place.
•
Chose the “BF” (bright field) position on the revolving disk of the phase contrast condenser.
• Iris diaphragm should be adjusted in accordance with numerical aperture of a lens. The best practice is to make the iris
diaphragm slightly smaller than the aperture of the selected lens. Open or close the iris diaphragm using the adjustment
screws. If the adjustment screw is turned to the right, the iris diaphragm is fully open. Note: The diaphragm is not intended
for adjusting the brightness of the illumination. To adjust the brightness, use the brightness adjustment knob.
•
Slide the filter holder, place the filter in it and then return the holder to its initial position.
•
To change the objective magnification, turn the revolving nosepiece until it clicks.
• Make sure that the lens does not touch the sample when adjusting the focus: Rotate the coarse focus knob until the
specimen is about 3.175mm (1/8") away from the lens.
• Looking into the eyepiece, slowly turn the coarse focusing knob until you can see the image of the observed specimen. Turn
the fine focusing knob to make the image clear. The fine focusing mechanism allows you to focus on the observed specimen
while using high magnifications.
•
When you use an oil immersion objective, the space between the specimen and the lens should be filled with immersion oil.
Raise the condenser to the upper position and put a drop of oil on the lens and on the cover glass of the specimen. Move the
revolving nosepiece back and forth to get rid of air bubbles in the oil. Then, fix the objective lens in its working position.
Make sure that oil fills the entire space between the objective lens and the specimen. After use, wipe the lens dry.
•
To adjust the position of the mechanical scale, turn the coarse focusing knob in a clockwise direction if you want to fix the
position of the mechanical scale or in a counterclockwise direction if you want to loosen it.
•
To place the specimen in the field of view, move the stage horizontally back and forth or left and right using the stage
moving knobs.
•
Look through the right eyepiece with your right eye and adjust the image sharpness with the coarse and fine focusing knobs.
Then, look through the left eyepiece with your left eye and rotate the diopter adjustment ring to equalize the difference
between your left and right eyes vision. Remember the setting for future use. Adjust the distance between the eyepiece
tubes of the binocular head so that the image merges into a single circle.
• Trinocular models: You can install the digital camera to the third eyepiece tube. Use the beam splitter to send the light to
the eyepieces or to the camera.
Phase-contrast device
Configuration and operating principle
Please refer to fig. 3. The device is designed for studying low-contrast objects that are not visible in the microscope
when observed in transmitted light in a bright field. It allows for observing unstained low-contrast specimens and living
microorganisms using the phase contrast method.
The light that passes through an unstained specimen changes the light wave phase, but these changes are invisible to the human
eye. To make such a specimen visible, it is necessary to convert the phase shifts of a light into changes in amplitude, which can
be observed. The phase contrast device (consisting of a phase condenser and phase objectives) makes the image of a specimen
contrast enough and suitable for research.
The phase condenser enables observing using the dark and bright field methods. The iris diaphragm under the revolving disk is
used for bright-field research, and in the disk itself there is a hole for the passage of the entire light beam.
Assembly and using
• Install the phase objectives into the revolving nosepiece and the auxiliary microscope into the microscope tube.
•
Install the phase condenser into a ring-shaped mount under the stage.
• Fully open the iris diaphragm of the phase condenser.
•
Rotate the revolving disk, select the desired annular diaphragm; the corresponding number will appear in the window of the
condenser (the magnification of the lens should coincide with the marking of the aperture of the phase-contrast device).
The “BF” position is intended for using the bright-field method, and the “DF” position is intended for research in a dark
field.
