Phase contrast microscopy in characteristics of material

1. PHASE
CONTRAST
MICRSCOPY
MANOJ ARAVINDH S
23PHY23

2. Basics to Know….
Interference
Phase
In Phase
Out of Phase

3. INTERFERENCE:
Two waves superpose(combine) to form a resultant wave of greater or lower or same amplitude.
PHASE:
Relationship between the two signals with each other.
IN PHASE:
Both the waves are at the highest peak. Two waves add together and create constructive interference, resulting in a
wave of greater amplitude.
OUT OF PHASE:
One wave is at the highest peak and other one is at the lowest peak. Two waves cancel each other out and create
destructive interference, resulting in a wave of lower amplitude.

4. History of Phase contrast Microscope
• Phase contrast Microscope was first described in 1934 by Dutch physicist Fritz
Zernike.
• The invention of this microscope helps us to study the live cells and the
cellular process.
• For his efforts, he was awarded the Nobel prize in 1953.

5. Phase contrast Microscope
Phase contrast Microscopy is an optical microscopy technique that converts
phase shifts in the light passing through a transparent specimen to
brightness changes in the image.

6. Principle of Phase contrast Microscope
• Phase contrast microscope is based on the principle that small phase changes in the light
rays introduce by the refractive index of the different parts of the object and the difference
in the thickness (cell density) into easily detected variations in light intensity.
• In simple terms, phase contrast microscopy is the translation of invisible phase shifts into
visible differences of intensities.
• The phase changes are not detectable to human eye whereas the brightness or light
intensity can be easily detected by the human eye.

8. Major Parts of the Microscope
1. Annular ring
2. Condenser lens
3. specimen table
4. objective lens
 Annular ring is the opaque lens which blocks most of the light from the light source. Hence it produces a
hollow cone of light.
 The condenser lens in a phase contrast microscope is a crucial optical component responsible for
illuminating the specimen with uniform and properly phased light.

9.  Specimen table is used to place the specimen.
The objective lens in a phase contrast microscope is a critical component responsible for gathering light
from the specimen and forming the primary image.
 The phase plate in phase contrast microscopy is a crucial optical element that introduces controlled
phase shifts to enhance contrast in transparent specimens.

10. Working
In a phase contrast microscope, light passing through the specimen undergoes phase shifts due to
variations in refractive index within the sample.
Illumination: Light from a source is directed through a condenser lens and a phase plate, which
introduces controlled phase shifts into the light.
Interaction with Specimen: The phase-shifted light illuminates the specimen, which contains
transparent or semi-transparent structures. As light passes through different parts of the specimen,
phase differences occur due to variations in refractive index.

11. phase Contrast: The phase differences between the direct and diffracted light waves are
converted into differences in brightness (contrast) by a phase contrast objective lens.
Image Formation: The phase contrast objective lens focuses the light onto the image plane,
where an eyepiece or camera records the specimen's enhanced contrast image.
Visualization: This contrast-enhanced image allows for the visualization of fine details and
structures within the specimen, even those that would be nearly invisible in conventional
bright-field microscopy.

12. ADVANTAGES
 The capacity to observe living cells.
 Specimens that need not to be killed, fixed or stain
to view under a microscope.
 High contrast, high resolution images.
DISADVANTAGES
 Not ideal for thick organisms.

13. “Life is between the phase of birth and
death. So contrast your visual and
observe clearly “
THANK YOU