Nature of learning starts by observing, and this is applicable especially in science, because all science is defined by observing.
Observing is primal method of the process of learning.
Human mind discovered many instruments for observing,
- For remote objects (telescope) and
- For objects too small for the eye to see (microscope).
Definition for compound light microscope can be made only by revealing some facts and previous data, because no definition can be concluded before analyzing and putting some history facts first.
Compound light microscope history
Etymology of the word microscope comes from Ancient Greece. It is combination of the word:
- mikrós, “small” and
- skopeîn, “to look”.
First and simple definition is that microscope is an instrument used to see objects that are too small for the naked eye.
The earliest forms of magnification were magnifying glasses used for inspecting small insects, but the inventors that create first microscope are father and son team, Hans and Zacharias in 1590.
Since then, history of microscope is filled with many inventors and scientists credited for today irreplaceable position of microscope in science. Microscopes are used in:
- Material science,
- Mineralogy and
enhancing our knowledge on everyday basis.
The most common is the optical (light) microscope, which uses light to image the sample. Light microscopes can reveal the structures of living cells and tissues, as well as of non-living samples such as rocks and semiconductors. Nowadays light-microscopy technology has evolved far beyond the first microscopes of Hooke and Leeuwenhoek.
Compound light microscope definition
Light microscopes can be simple light microscopes or compound light microscopes.
Light microscopes send light that first focuses the light into a tight beam and then passes that light through a sample, which creates an image. Further, image passes through one or more lenses (depending of the type of the microscope) to magnify it until it reaches the user’s eye or a camera.
Simple light microscopes use a single lens to magnify an object and cannot reach high magnification, and compound light microscopes use two sets of lenses:
- an objective lens and
- an eyepiece, in order to produce images.
Compound light microscope
Compound means more than one lens and light because of the method of light transmitting the image to the eye. In more specific terms, it is compound because it’s made of two lens systems.
There are three structural components of a compound microscope:
- base and
The body contains optical parts in the upper part of the microscope; base, supports the microscope and houses the illuminator; and arm connects to the base and supports the microscope head.
All parts are:
- fine adjustment knob,
- power switch,
- body tube,
- stage clips,
- stage stop,
- coarse adjustment knob,
- light source.
The objective or one lens system is close to the specimen, producing an enlarged image of the specimen. Then, this image is enlarged by eyepiece (ocular), or the other lens system, magnifying the image of the primary lens, near to the spectator’s eye. The two lens systems are located at opposite ends of the body tube of the microscope.
Objective lenses are the primary optical lenses on a microscope. Most microscopes contain three or four lenses. Objectives can be forward or rear-facing. The objective lens is located at the lower end of the body tube and the observer often begins viewing the specimen with the objective of lowest power and then examines further with objectives of higher power. The image is brought into focus by turning either the coarse or fine adjustment knob, which focuses the image by moving the body tube up and down.
Magnifying power of a compound microscope
The eyepiece (or ocular) is near to the eye of the spectator, so ocular is what you look through at the top of the microscope. Standard eyepieces have a magnifying power of 10x and objectives of 10x, 45x, and 100x magnifying powers. Therefore, the magnifying power of the entire microscope would range from 100x to 1000x the size of the actual specimen.
The result of magnifying powers of the eyepiece and the objective is the magnifying power of a compound microscope. Because of the multiple lenses, compound light microscope is capable to reveal a great amount of detail in samples. Because it contains its own light source in its base, a compound light microscope is also considered as a bright field microscope.
Uses and future of Compound Light Microscopes
The compound microscope is widely used in:
- biology, and
- medicine in the examination of bacteria, other unicellular organisms, plant and animal cells.
It has been very important in the development of the biological sciences and medicine.
China has become a major supplier of microscopes for everyday use and this trend of the market had a favorable effect on the price of microscopes, enabling their path beyond the scientists to everyday commercial and individual use.
Compared to simple light microscopes with ability to magnify an object to 266X, modern compound light microscope can magnify an object from 1000X to 2000X times the specimen’s original diameter.
Today, microscopes have even entered the digital age, using charge-coupled devices (CCDs) and digital cameras to capture images. The great improvement of the light microscope is due to new light sources like halogen, fluorescent and LED.
The most recent innovation is arrival of the digital microscope. Digital microscopes allow live image transmission to a TV or computer screen. They have helped to develop microphotography. They use the method of integrating digital camera on the trinocular port of a standard microscope.
Also, one more of the original innovations have been Dino-Lite digital microscopes. They offer low power zoom capability with magnification up to 500x, and they are not much larger than a fat pen. Because they are handheld digital microscopes, they are easy to use, so these microscopes had a marked impact on industrial inspection applications.
Microscopy, as a technique in scientific investigation, has had a key role in uncovering nature’s beauty so in conclusion, let’s finish with the quote from the authors Lelio Orci & Michael Pepper:
“As long as there is a hunger for knowledge and a deep desire to uncover the truth, microscopy will continue to unveil Mother Nature’s deepest and most beautiful secrets.”