The dark field condenser A 1,36-1,25 MI is designed to illuminate low-contrast objects on the Micromed microscopes. The condenser is used with lenses of immersion systems.
Darkfield illumination is used to examine transparent objects invisible under a microscope under normal brightfield illumination.
The numerical aperture of the dark field condenser is greater than the aperture of the objectives, so the light rays coming out of the condenser do not enter the objective, and in the absence of objects in the field of view of the microscope it is dark.
In the presence of objects, the light reflected from them is collected by the objective, and a bright contrasting image of objects is formed against the dark background of the microscope field of view.
Numerical aperture of this condenser model A = 1.25-1.36 MI
Condenser working distance, mm 1.25 - 1.4
Application of the dark field condenser А 1,36-1,25
Focus the microscope with 10x objective and brightfield condenser onto the surface of the slide (in the area without the object). The thickness of the slide when working with the dark field method should be no more than 1.1 mm.
Install a А 1,36-1,25 dark field condenser instead of the bright field condenser, apply a drop of immersion liquid to the front lens and raise the condenser until the immersion layer touches the glass slide.
Make sure that there is no light in the tube with the eyepiece removed. In the presence of flare, remove it by moving the condenser with the centering screws and focusing (within the immersion layer).
Focus the microscope on the installed object and start research.
If focusing fails, then it is necessary to return to the bright field condenser and focus the microscope on the area with the object with the condenser aperture diaphragm completely closed, then replace the bright field condenser with the А 1,36-1,25 condenser and apply a drop of immersion liquid to the front lens. A light ring with a dark spot in the center should appear in the field of view. Raise the condenser to achieve the appearance of only a light spot (if the immersion layer is not enough, the shape of the light spot or ring is incorrect). If the illuminated spot moves with other lenses from the kit, use the centering screws of the condenser.