The document discusses the phase contrast microscope. It was first described in 1934 by Dutch physicist Fritz Zernike, who later won the Nobel Prize in Physics in 1953. Phase contrast microscopes use interference of light waves passing through specimens to create high-contrast images without staining. They are commonly used to view transparent or unstained samples like living cells and small organisms.

1. V.MUTHUMEENA
III BSc Biotechnology
Bon Secours College For Women,
Thanjavur.

2.  Phase contrast microscope was first described
in 1934 by DUTCH physicist FRITZ ZERNIKE.
 He awarded by Nobel prize in physics in 1953.
 Green light used in Phase contrast microscope.

3.  Application for Phase contrast microscope
equipment range from the study of living
biological specimens , medical applications ,
study of live blood cells and other biological
and science applications.
 Most commonly used to provide contrast of
transparent specimens such as living cells or
small organisms.

4.  Use full in observing cells cultured in vitro during
mitosis.
 Unstained/living biological specimens have little
contrast with their surrounding medium.

5.  Posses – light source
 Condenser
 Objective lens
 Ocular lens
 CHARACTERS OF LIGHT(Two types):
Diffraction
Interference

6. o Annular diaphragm
o Phase contrast ring

7. o Phase contrast microscopes use refraction and
interference caused by structures in a specimens
to create high contrast ,high resolution images
without staining.
o It is the oldest and simplest type microscope that
creates an image by altering the wave lengths of
light rays passing through the specimen.

8. o When the wave lengths are out of phase, wave
troughs will cancel out wave peaks, which is called
destructive interference.

9.  Transparent specimens in living cells and small
organisms.
 Cell cultured in vitro during mitosis.
 Enable visualization of internal cellular
components.
 Study of cytoskeleton.
 Visualize all types of cellular movements.

10.  Living cells can be examined in their natural state.
 The dynamics of ongoing biological processes
can be observed and recorded in high contrast
with sharp clarity of minute specimen detail.
 It contain special phase contrast objectives and a
special phase contrast condenser.

11.  Annuli or rings limit the aperture to some extent ,
which decreases resolution.
 Not ideal for thick organisms or particles.
 Images may appear grey or green if white or
green lights are used respectively, resulting in
poor photomicrography.