Phase Contrast Microscopy

Phase contract microscopy technique started in the year 1930’s when a Dutch physicist invented this extraordinary device and made him a Nobel Prize winner for his invention. A device too magnificent that it has a contrast enhancing technique that can be utilized to produce high contrast images of transparent specimens such as living cells and microorganisms. It is a type of light microscope that enhances contrasts of transparent and colorless objects by influencing the optical path of light. But first, let’s define what a phase contrast really is. This is a method used in microscopy and developed in the early 20th century by a Dutch physicist. He discovered that if you speed up the direct light path, you can cause destructive interference patterns in the viewed image; these patterns make details in the image appear darker against a light background. You may wonder what causes these interference patterns, but Zernike developed a system of rings located both in the objective lens and in the condenser system and when aligned properly, light waves emitted from the illuminator arrive at your eye ½ wavelengths out of phase and the image of the specimen then becomes greatly enhanced. They appear against a grayish background if used with plain white light, and appear against a green background if used with a green filter in light path.

Research shows that the human eye measures only the energy of light arriving on the retina, so changes in phase are not easily observed, yet often these changes in phase carry a large amount of information. As you all know, phase is only useful on specimens that are color less and transparent and usually difficult to distinguish from their surroundings and very useful in showing details in certain specimens such as cell parts in protozoans, bacteria, sperm tails and other types of unstained cells, others are lithographic patterns, fibers, latex dispersions, and glass fragments. This phase contrast microscope is one of the most commonly used biological contrast enhancing technique today. Phase contrast microscopy is microscopy technique that does not need staining to view the slide and made it possible to study cell cycle. It’s wide variety of microscopic applications include molecular and cellular biology research, clinical and medical diagnosis of health conditions, animal breeding, mold spore identification, environmental air pollution monitoring, mold and mildew detection and abatement, dust mite control, asbestos testing and a lot more applications. So surf and enjoy our informative articles as you browse the pages of this site.