How Is Electron Microscope Different From Light Microscope

In this how is electron microscope different from light microscope post we have briefly explained about key differences between light microscope and electron microscope.

The difference between a light microscope and electron microscope is mostly due to two characteristics: the source of illumination and the type of lens.

Source of illumination: A microscope’s property that ensures the object or specimen’s clear visibility while also adding brightness. The fundamental role of the lens in a microscope, which varies depending on the type of microscope accessible, is to magnify the image.

The image is formed by a direct source of light waves in the light microscope, whereas the image is formed by an accelerated electron beam in the electron microscope. Glass-based lenses are used in light microscopes, and they include an eyepiece, objective, and condenser lens. The electromagnetic lens, which combines a condenser, objective, and projector lens, is used in electron microscopes. The differences between light microscope and electron microscope will be discussed here.

How Is Electron Microscope Different From Light Microscope

Images of light microscope and electron microscope

Difference Between Light Microscope and Electron Microscope

Properties

Light microscope

Electron microscope

Discovery

Invented by Zoocharia Janseen in 1590.

Invented by Ernst Ruska and Max Knoll in 1931.

Alternatively Known As

Optical microscope

Beam microscope

Principle

To form the picture of the specimen, optical lenses are used to bend light beams.

To form the picture of the specimen, optical lenses are used to bend light beams.

Illuminating Source

Illuminating source is visible light (white light)

Illuminating source is accelerated beam of electrons from a tungsten filament.

Wave Length

Wave length of light used is 450 to 750 nm

Wave length of electron beam used is 0.5 Å

Structure

Light microscopes are smaller and lighter.

Heavier and larger in size.

Lenses

All lenses are made of glass or quarts (condenser, objective, and eye piece lenses).

The entire lens system is made up of electromagnets; no glass lenses are used.

Vacuum

A vacuum cleaner isn’t required.

A vacuum is required for smooth operation.

Specimen Type

Fixed or unfixed, stained or unstained, living or non-living.

Fixed, stained, and non-living.

Specimen Observed

Both living and dead specimens are on display.

Only the remains of deceased specimens are on display.

Preparation Time

Preparation of specimens is a matter of a few hours.

Preparation of specimens is a matter of a few hours.

Specimen Preparation

Less tedious and simple.

More expertise is necessary, both in the preparation of specimens and in the interpretation of EM pictures (due to artifacts).

Thickness Of Specimen

The optical microscope has a low-resolution of approximately 0.25µm.

It has a higher resolution power of approximately 0.001µ than an optical one.

Dehydration Specimen

Specimens need not be dehydrated before viewing.

Only dehydrated specimens are used.

Coating Of Specimen

Stained by colored dyes for proper visualization.

Coated with heavy metals to reflect electrons.

Mounting Of Specimen

Specimen is mounted on glass slide

Specimen is mounded on metallic grid (usually copper)

Focusing

Focusing is by adjusting the lens position mechanically

Focusing is done by adjusting the power of electric current to the electromagnetic lenses

Magnification Power

Magnification limit is less, possible limit is 1500 X

Magnification limit is very high, possible limit is 500000X

Resolving Power

Low resolving power (often less than 0.30µm).

The high resolving power of up to 0.001µm, which is approximately 250 times that of a light microscope.

Electricity

A high voltage of electricity is not necessary.

A high voltage of minimum 50,000 volts is necessary.

Cooling System

The system does not have a cooling method enabled.

It has a cooling mode that uses high current to dissipate heat.

Size Of Instrument

The instrument is smaller in size and can be used as a desktop instrument.

Separate systems such as a cooling system, a vacuum system, and an image processing system are all involved in the bigger instrument.

Price

Price is much cheaper when compared to electron microscope

Electron microscope is extremely costly instrument

Risk Of Radiation

There is no risk of radiation.

Risk of radiation is present.

Filament

It does not use any filament.

It uses tungsten filament to release electrons.

Suitability

Suitable for most basic functions, and is very common in schools and other learning institutions.

Limited to specialized use such as research.

Application

It is used for the study of detailed gross internal structure.

It is used in the study of the external surface, the ultrastructure of cells and very small organisms.

differences between light microscope and electron microscope 4
differences between light microscope and electron microscope 3

Difference between light microscope and electron microscope image results

Key Differences Between Light Microscope and Electron Microscope

  1. One distinct characteristic is that a light microscope uses a light source, whereas an electron microscope employs an electron beam.
  2. The light microscope has a low magnification and resolving power of 1000X and 0.2µm, respectively, on the light microscope. An electron microscope, on the other hand, has a high magnification and resolving power of 10,000X and 0.001µm.
  3. In a light microscope, the item is viewed straight through the eyepiece. The electron microscope, on the other hand, uses a fluorescent screen to display an enlarged view of the item.
  4. Because of its complicated architecture, an electron microscope requires more power and technical knowledge to operate, but a light microscope requires less power and is easier to operate.
  5. An electron microscope has a vacuum system, tungsten filament, cooling system, and radiation leakage, but a light microscope does not.
  6. In comparison to the light microscope and electron microscope, sample preparation is simple with a light microscope.
  7. In a light microscope, thick specimens up to 5 µm can be easily observed, however in an electron microscope, only thin specimens up to 0.1 µm can be visualised.
  8. The chemical dyes used to stain the specimens provide contrast to the microscopic image, resulting in a coloured specimen. In the case of an electron  microscope, however, a specimen is coated with heavy metals that attract the electron beam, resulting in a black and white specimen.
  9. Bright field, dark field, phase contrast, and fluorescent field microscopes are the four types of light microscopes. TEM (Transmission Electron Microscope), SEM (Scanning Electron Microscope), and STEM (Scanning Transmission Electron Microscope) are three types of electronic microscopes.

Further Readings

Reference