PHASE CONTRAST (OPTIONAL)
Use of phase contrast with the MT-420 and
MT-430 microscope
The phase contrast method was designed
in 1934 by the Dutchman Frits Zernike to
observe very thin or transparent objects. This
technique uses the fact that light traveling
through tissue undergoes a phase shift due
to diffraction.
By recombining the phase shifted light with
the background light, a contrasted image
appears in the eyepiece.
Using the Zernike phase contrast set
Any MT-420 and MT-430 model with a Zernike phase contrast set comes with the phase
contrast condenser and objectives already mounted and centered on your microscope. If you
suspect misalignment or want to check the alignment please see the next point for “centering the
phase rings”.
The height of condenser can be adjusted by turning the rack and pinion up and down. By doing
this the light beam will be focused more on the specimen for maximum resolution.
The Zernike phase disc has five positions:
“0” for bright field observation, this position also has an iris diaphragm.
“10”
“20”
“40”
“100”
These positions correspond to the respective phase contrast objectives 10X, 20X, 40X an 100X.
When the condenser is in the “0” position, the objectives can be used for bright field observation.
For phase contrast, the condenser position should match the objective used. Meaning that when
the condenser is in position “40” the objective used should also be 40X.