Stereo Microscope | 3 Important parts | Magnification | Illumination

Stereo Microscope | 3 Important parts | Magnification | Illumination

STEREO MICROSCOPE

CONTENTS

What is a stereo microscope?

The stereo microscope is used to examine samples at low magnification. This is done by working with the phenomenon of reflection of the light rays from the sample instead of transmission. These microscopes have different angles of viewing for the left and right eye as it uses two separate optical paths for the eyepiece and the objective. The resultant microscopic image formed is a 3D or Stereo image. These types of microscopes are generally used to observe and view objects that do not allow light rays to pass through them. Such instruments are used for manufacturing, quality control, coin collecting, and botany study. Stereo microscopes are often utilized for carrying out processes such as watch-making, dissection, circuit board inspection or manufacture, and forensic engineering.

stereo microscope
A stereo microscope. Image source: GcG(jawp), Optical stereo microscope nikon smz10, marked as public domain, more details on Wikimedia Commons

What are the parts of a stereo microscope?

  1. Viewing head/body: The viewing head is present in the top of the microscope and contains the optical components like the eyepiece lens, the reticle and the relay lens.
  2. Focus block: The focus block helps in adjusting the focused image of the sample by altering the position of the objective lens.
  3. Luminous stand: The luminous stand comprises of the stage where the sample is placed and the source of illumination of the sample.
Stereo Microscope | 3 Important parts | Magnification | Illumination
Parts of a stereo microscope. A – Objective B – Galilean telescopes (rotating objectivesC – Zoom control D – Internal objective E – Prism F – Relay lens G – Reticle H – Eyepiece Image source: TamasflexSztereomikCC BY-SA 3.0

What is the magnification of stereo microscope?

Stereo microscopes have two different types of magnification: fixed magnification and zoom or pancratic magnification. Fixed magnification is due to the set of objective lenses. The zoom or pancratic magnification is provided by the auxiliary objectives. The total magnification of a microscopic system is given by the product of the zoom magnification and the fixed magnification. The same set of objective lenses can be designed to produce two different types of magnification in a stereo microscopic system. The Galilean optical system is responsible for providing the intermediate magnification between the fixed magnification and zoom or pancratic magnification.

What type of illumination is used in stereo microscopy?

Small sample specimens require a high power/intensity light in order to be viewed properly under a microscope. Fiber optic light sources are generally preferred over other types of sources as they provide high-intensity illumination of given power input. These light sources are compact and can easily fin in the microscope stand.

However, these light sources heat up easily and often require a cooling agent for better performance. Sometimes a number of fiber optic light stalks are used together to further increase the level of illuminance. These light stalks are appropriate for illuminating the specimen and does not interfere with the image formed by the microscope. These light stalks are generally mobile i.e. it can be moved depending on the specimen’s position.

Recent microscopes have incorporated the use of high power LED lamps for sample illumination. These are capable of producing a spectrum of light and are considered effective in examining biological samples specially.

Stereo Microscope | 3 Important parts | Magnification | Illumination
A stereo microscope with an illuminated specimen. Image source: Monique SacomoriLooking at the butterflyCC BY-SA 4.0

What is the difference between a stereomicroscope and a digital microscope?

A digital microscope and a stereo microscope differ mainly in terms of their magnification ranges. The magnification in a stereo microscope is obtained by multiplying the magnification of the objective lens with the magnification of the eyepiece lens. A digital microscope does not have an eyepiece, therefore, its magnification is equal to the product of the objective magnification with the CCD-monitor pair magnification or electronic magnification. The electronic magnification is calculated by dividing the dimension of the monitor image by the dimension of the sample.

The rays fall directly on the CCD screen in a digital microscope. This can result in forming images with a better resolution than stereo microscopes. Unlike digital microscopes, stereo microscopes consider the effect of human vision properties into consideration.

What is the difference between a stereomicroscope and a compound microscope?

  • A stereo microscope is used to examine samples at low magnification. This is done by working with the phenomenon of reflection of the light rays from the sample instead of transmission.
  • These microscopes have different angles of viewing for the left and right eye as it uses two separate optical paths for the eyepiece and the objective.
  • Stereo microscopic systems are used for observing objects that do not allow light to pass through them whereas most microscopes view samples that transmit light.

To know more about microscopes visit https://lambdageeks.com/types-of-microscope/

About Sanchari Chakraborty

Stereo Microscope | 3 Important parts | Magnification | IlluminationI am an eager learner, currently invested in the field of Applied Optics and Photonics. I am also an active member of SPIE (International society for optics and photonics) and OSI(Optical Society of India). My articles are aimed towards bringing quality science research topics to light in a simple yet informative way. Science has been evolving since time immemorial. So, I try my bit to tap into the evolution and present it to the readers.

Let's connect through https://www.linkedin.com/in/sanchari-chakraborty-7b33b416a/

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