Compound Light Microscope

• The objective lens is the most important part of the microscope, as it determines the magnification.
• The compound light microscope was developed in 1950 by Zaccharias Janssen and Hans Lipperhey, who experimented with two lenses placed at opposite ends of a tube and were amazed at the greatly enlarged image.
• Anton Van Leeuwenhoek was able to make a simple microscope made of a single lens that could magnify an object 270 times, and was the first to observe bacteria, yeast and red blood cells.
• Robert Hooke spent much of his life improving the design and capabilities of microscopes, and then discovered tiny compartments in a thin slice of cork and called them cells.
• There are two types of microscopes: the simple microscope, composed of one lens and providing relatively low magnifying powers, and the compound microscope, composed of two or more lenses that provide powerful magnification.
• The parts of the compound light microscope are categorized into three major parts: the illuminating parts, the magnifying parts, and the mechanical parts.
• The illuminating parts of the compound light microscope provide light, with two sources of light: a natural source (sunlight) and an artificial source (light bulb).
• The condenser, found beneath the stage, concentrates the reflected light from the mirror to the object being examined.
• The iris diaphragm, a thin structure with adjustable opening located at the mouth of the condenser, is used to regulate the intensity of light which enters the condenser.
• The magnifying parts of the compound light microscope are the parts that enlarge the object or specimen.
• The mechanical parts of the compound light microscope are parts of the microscope that support, adjust, connect, and move other parts.
• A microscope is an instrument used to see objects that are too small for the naked eye.
• The science of investigating small objects using such an instrument is called microscopy.
• Microscopic means invisible to the naked eye unless aided by a microscope.
• Anton Van Leeuwenhoek is known as the Father of Microscopy because of his discovery of animalcules.
• The mirror is located beneath the stage and has concave and plane surfaces to gather and direct light in order to illuminate the object.
• The Electric Lamp is a built-in illuminator beneath the stage that may be used if sunlight is not preferred or is not available.
• The Illuminating parts of the CLM has 4 parts, the Condenser, Electric Lamp and the Iris Diaphragm.
• An Ocular or Eyepiece is another set of lens found on top of the body tube which functions to further magnify the image produced by the objective lenses. It usuallgy ranges from 5x to 15x.
• Objectives are the metal cylinders attached below the nosepiece and contained especially ground and polished lenses
• Types of Objectives are Low Power Objective (LPO), High Power Objective (HPO), and Oil Immersion Objective (OIO).
• LPO gives the lowest magnification, usually 10x.
• HPO gives higher magnification usually 40x or 43x.
• OIO gives the highest magnification, usually 97x or 100x, and is used wet either with cedar wood oil or synthetic oil.
• The formula for the total magnification is Magnification = Objective Lens × Eyepiece Lens.
• The 2 magnifying parts are the Ocular/Eyepiece and the Objectives.
• There are 13 Mechanical parts, namely the Base, Pillar, Inclination joint, Arm/Neck, Stage, Stage Clips, Stage Opening, Body Tube, Draw Tube, Revolving/Rotating Nosepiece, Dust Shield, Coarse Adjustment Knob and the Fine Adjustment Knob.
• A parfocal lens is a lens that stays in focus when magnification/focal length is changed.
• The base is the bottommost portion that supports the entire/lower microscope.
• The pillar is the part above the base that supports the other parts.
• The inclination joint is the part that allows the tilting of the microscope for convenience of the user.
• The Arm/Neck is a curved/slanted part which is held while carrying the microscope.
• The stage is the platform where object to be examined is placed.
• The stage clips secures the specimen to the stage.
• The stage opening allows light to pass through the stage so that we can be able to see the specimen.
• The body tube is attached to the arm and bears the lensed.
• The draw tube is a cylindrical structure on top of the body tube that holds the ocular lenses.
• The revolving/rotating nosepiece is the rotating disc where the objectives are attached.
• The dust shield lies on top of the nosepiece and keeps dust from settling on the objectives.
• The coarse adjustment knob is geared to the body tube which elevates or lowers when rotated bringing the object into approximate focus.