Microscope

Parts of a Microscope and Their Functions

Eyepiece

  • The eyepiece (ocular lens) is the part closest to the viewer’s eye.

  • Located at the top of the microscope, it is used to look at the specimen.

  • Magnification powers vary from 5X to 30X, with common lenses at 10X or 15X.

Eyepiece Tube

  • The eyepiece tube holds the eyepiece just above the objective lens.

  • Some designs are flexible (like binocular microscopes) for better visualization based on distance; monocular microscopes have a non-flexible eyepiece tube.

Diopter Adjustment

  • Present only in binocular microscopes, this control knob adjusts the focus on one eyepiece.

  • Compensates for differences in vision between the viewer’s two eyes.

Nose Piece

  • The nose piece is a circular structure housing all the objective lenses, also known as the revolving turret.

  • It can rotate to increase or decrease magnification by changing the objective lens.

Objective Lenses

  • Closest lenses to the specimen; typical microscopes have 3 to 4 lenses with varying powers (4X, 10X, 40X, 100X).

  • They magnify the specimen for the first time after it receives transmitted light.

Fine Adjustment Knob

  • A smaller knob used to sharpen the image, mostly under high power magnification.

Coarse Adjustment Knob

  • A larger knob used for focusing under low power magnification, rapidly moving the stage up or down.

Stage

  • The platform where the specimen is placed for viewing.

  • Includes stage clips to hold specimen slides and can feature a mechanical stage for slide control via knobs.

Stage Control Knobs

  • Control knobs used to move the stage mechanically.

  • One knob moves the stage left and right, while the other moves it forward and backward.

Aperture

  • A hole in the stage that allows transmitted light from the source to reach the specimen.

Microscopic Illuminator

  • The light source for the microscope, which may use a mirror to reflect external light or bulbs.

  • Commonly uses tungsten-halogen lamps or 75-150W Xenon lamps.

Condenser

  • Lenses that focus light from the illuminator onto the specimen.

  • Positioned under the stage, critical for producing clear images at high magnifications (400X and above).

Diaphragm

  • Also known as the iris, it is under the stage and controls the amount of light reaching the specimen.

  • Adjustable to control light intensity and beam size.

Condenser Focus Knob

  • Moves the condenser up or down, controlling the focus of light on the specimen.

Abbe Condenser

  • Designed for high-quality microscopes, allowing for high magnification (over 400X) with a movable condenser.

Rack Stop

  • Controls the vertical movement of the stage, preventing the objective lens from getting too close to the specimen, protecting both.

Light Switch

  • An electrical control device for turning the illuminator on and off.

Brightness Adjustment

  • Regulates voltage supplied to the light bulb, controlling the intensity (brightness) of the light.