Forensicspedia

Login / Register
Menu
Login / Register
Created with Fabric.js 5.2.4
Created with Fabric.js 5.2.4
Login
Categories
Uncategorized

PHASE CONTRAST MICROSCOPE

INTRODUCTION

Phase contrast microscopy is an optical microscopy based on the illumination technique. It converts the small phase shifts that occur when light passes through a transparent object into amplitude differences on the resultant images which is detectable by human eye.

This type of light microscope does not require staining of sample to be visible. They simply magnify the contrast of transparent and colourless objects by influencing the optical path of light.

HISTORY

This type of microscope was first invented by Frits Zernike in 1932 which made me own the Nobel Prize in 1953 for its revolutionary usage in biological and medical researches.

PRINCIPLE

When light passes through an object that is optically denser that its background there is a phase shift with respect to unaffected bypassing background light. The phase contrast microscope converts this phase shifts into change in amplitude which is visible in the image contrast. There are 2 rings that allows partial light to pass through the sample and the rest is blocked, which creates the required contrast. These rings are

  1. Annular rings which lie between condenser and light source
  2. Phase ring which is in between objective lens and image plane.

WORKING

  1. A tungsten halogen lamp is used as an illuminating source which passes trough a collector lens focused on a specialized annular ring.
  2. The light waves then pass through the annular ring and falls on the specimen the light causing an illumination. The waves then either passes un-deviated or are diffracted and retarded in phase by structures and phase gradients present in the specimen.
  3. The rays are collected by the objective and separated at the rear focal plane by the phase plate.

PARTS OF PHASE CONTRAST MICROSCOPE

  1. It is present below the condenser.
  2. It is made up of a circular disc having circular annular groove.
  3. The light rays are allowed to pass through the annular groove and falls on the specimen or object to be studied.
  4. The annular phase plate is placed at the back focal plane where the objective develops an image.

PHASE PLATE

  1. It is either negative phase plate having a thick circular area or a positive phase plate having a thin circular groove.
  2. This thick or thin area on the phase plate is called the conjugate area.
  3. This phase plate is a transparent disc.
  4. The direct rays pass through the annular groove whereas the diffracted rays pass through the region outside the groove.
  5. This helps to separate the direct rays from the diffracted rays.
  6. Depending upon the different refractive indices of different cell components, the object to be studied shows a different degree of contrast in this micro­scope.

USES

  1. A living cell, microorganisms, thin tissue slices, fibres, glass fragments etc.
  2. They also help to study cell cycle
  3. These microscopes are widely used in biological researches.

ADVANTAGES

  1. Living cells can be observed in their natural state.
  2. It makes a highly transparent object more visible.
  3. No special preparation of fixation or staining etc. is needed to study an object under a phase-contrast microscope which is quite time efficient.
  4. It made it possible for biologists to study living cells and how they proliferate through cell division.
  5. Examining intracellular components of living cells at relatively high resolution.

LIMITATION

  1. Phase-contrast condensers and objective lenses add considerable cost to a microscope.
    1. The considerable high-cost results in phase contrast microscope is often not used in teaching labs except perhaps in classes in the health professions.
    1. To use phase-contrast the light path must be aligned.
    1. Generally, requires lighter for phase contrast for creating a bright view contrast with the background.

Author- Satarupa Chatterjee

Sam Higginbottom University of Agriculture

Publish your Article with us for FREE…Click here

REFERENCES

  1. https://en.wikipedia.org/wiki/Phase-contrast_microscopy
  2. https://www.ruf.rice.edu/~bioslabs/methods/microscopy/phase.html
  3. IMAGE https://encryptedtbn0.gstatic.com/images?q=tbn:ANd9GcSKYfMTtf9Q96q9a3uR3bD_hGsJVZDL6WlDgjBphe4j8BWufRhW6FTYzSm1Ammo-_txJzI&usqp=CAU

117 replies on “PHASE CONTRAST MICROSCOPE”

Купить тепловизоры для наблюдения profoptica.com.ua для наблюдения и охоты Grand Pulsar Официальная гарантия 3 года Доставка по Украине Pulsar, Infiray(Iray), Hikvision, Pard Цена от 700$.

Купить тепловизоры для военных profoptica.com.ua FLIR серии ONE, TG, EX и С от официального дилера. Бесплатная доставка по всей стране. 2 года официальной гарантии. Заходите!

Купить тепловизоры Профоптика FLIR серии ONE, TG, EX и С от официального дилера. Бесплатная доставка по всей стране. 2 года официальной гарантии. Заходите!

ТОП-овое рекламное digital агентство lasuerte.ua предлагает комплексные решения для товаров и услуг в любой сфере бизнеса. Эффективные стратегии продвижения, команда.

Что предлагает наше рекламное агентство интернет маркетинг lasuerte.ua рекламы – Анализ бизнес-процессов – Построение воронки продаж – Интеграция всех сайтов, соц. сетей, телефонии.

Цены на зарядные станции profoptica.com.ua в нашем магазине приятно вас удивят, при этом качество остается на высоте.

На выставке показали, как зарядные станции Bluetti profoptica.com.ua могут решить проблемы с энергоснабжением.

Станция аккумулятор profoptica.com.ua поможет эффективно зарядить все ваши устройства, используя автономное питание.

With everything that seems to be building throughout this particular subject matter, your perspectives happen to be somewhat stimulating. Even so, I beg your pardon, because I can not give credence to your whole suggestion, all be it stimulating none the less. It seems to everybody that your comments are actually not completely validated and in reality you are generally your self not entirely convinced of the assertion. In any event I did appreciate reading it.

Thanks for sharing excellent informations. Your site is very cool. I’m impressed by the details that you¦ve on this website. It reveals how nicely you understand this subject. Bookmarked this web page, will come back for more articles. You, my pal, ROCK! I found simply the info I already searched all over the place and just couldn’t come across. What a great web-site.

Новичкам будет интересно предложение ггбет бездепозитный бонус https://moto-portal.com.ua/, которое позволяет начать игру без пополнения счета. Это хорошая возможность протестировать платформу.

Leave a Reply

Your email address will not be published. Required fields are marked *

You cannot copy content of this page