Light microscope

LIGHT MICROSCOPY by SIVASANGARI SHANMUGAM
The optical microscope, The functions of a light microscope is based on its ability to focus a beam of light through, which is very small and transparent, to produce an image.

1. SIVASANGARI SHANMUGAM LIGHT MICROSCOPY

2. CONTENTS Introduction Types Principles How does it work? Applications Advantages Disadvantages

3. INTRODUCTION Also known as optical microscope . It is a biology laboratory instrument . That is uses visible light to detect and magnify very small objects & enlarging them. They use lens to focus light on the specimen, magnifying it thus producing an image. The specimen is normally placed close to the microscopic lens. Microscope magnification varies greatly depending on the types and number of lenses.

4. TYPES There are four types of microscope

5. TYPES

6. The functions of light microscope is based on its ability to focus a beam of light through, which is very small and transparent, to produce an image. The image is then passed through one (or) two lenses for magnification for viewing. The transparency of the specimen allows easy and quick penetration of light. Specimens can vary from bacterial to cells and other microbial particles.

7. PRINCIPLE Light is produced from either an internal (or) external light source and passes through the iris diaphragm, a hole variable size which controls the amount of light reaching the specimen. The light then passes through the condenser which focuses the light onto the specimen. The slide is held on the stage at 90° to the path of light which next travels through the specimen. The objective lens magnifies the image of the specimen before the light travels through the barrel of the microscope. Finally light is passes through the eyepieces lens & into the viewer’s eye which sends impulses to the brain which in turn interprets the image.

8. PARTS OF LIGHT MICROSCOPE Eye lens/Ocular lens Objective lens Condenser Beam of light Specimen stage Aperture diaphragm

9. Objective lens - made up of six or  more glasses, which make the image clear from the object. Condenser - mounted below the stage which focuses a beam of light onto the specimen. It can be fixed or movable, to adjust the quality of light, but this entirely depends on the microscope. Stage - where the specimen is placed, allowing movement of the specimen around for better viewing with the flexible knobs and it is where the light is focused on.   Light illuminator/mirror  - found at the base or on the microbes of the nosepiece. Aperture diaphragm - known as the contrast, which controls the diameter of the beam of light that passes through the condenser.

10. HOW DOES IT WORKS?

11. HOW DOES IT WORKS? Light microscope is compound microscope which means that contain at least two lenses. Lenses are bended glass pieces. Light from the mirror is reflected up through the specimen, to be viewed, into the powerful objective lens, which produce the on magnification. The image produced by objective lens is than magnified again by the eyepiece lens, which act as a single magnifying glass. The magnified image can be seen by looking into the eyepiece lens. Important factors are Magnification, Resolution, Contrast.

12. APPLICATIONS A combination of staining and light microscopy can allow scientists to identify different kinds of bacteria. Light microscope play a large part in today’s biology. Observe real time movement in cells and organisms. Biologist use microbes to observe objects and details at a cellular level to learn more about the building blocks of all organisms.

13. ADVANTAGES Relatively easy to use. Small and Lightweight. It offer high levels of observational quality. It is unaffected by electromagnetic fields. Do not require radiation to operate. Require very little training. Allow to observe living organisms. Have minor maintenance cost compared to other models. Fully adjustable to the comfort level of the user.

14. DISADVANTAGES Have a lower resolution. Making it challenging to view living internal structures. Cannot operate in darkness. Cannot provide 3D renderings. Very low magnification caps.

15. OTHER TYPES The modern types of Light Microscopes include: Bright Field Light Microscope Phase Contrast Light Microscope Dark Field Light Microscope Fluorescence Light Microscope Confocal Light microscope

16. REFERENCE https://study.com/academy/lesson/light-microscope-definition-uses-parts.html https://www.thoughtco.com/history-of-the-microscope-1992146 https://www.studyblue.com/notes/note/n/chapter-2-microscopy-exam-i/deck/9442340 https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/light-microscopes https://www.sciencedirect.com/science/article/pii/B9781782420743000179 https://www.quora.com/What-is-the-major-difference-between-Phase-contrast-microscopy-and-Dark-field-microscopy

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