top of page
Search
  • Stephen Wilkinson

What is a Compound Microscope?

Updated: Mar 23, 2021

The compound microscope is the most common type of microscope – the one most of us first encounter in our younger days, and the first that many people ever use.

The term “compound” refers to the microscope’s optical system. This consists of two main lenses: the objective lens, positioned closest to the object being viewed, and the eyepiece lens, through which the user looks. These two lenses are arranged at opposite ends of a tube, in such a way that the magnified image produced by the objective lens travels to the eyepiece lens, where it is further magnified before finally being viewed.

Binocular Compound Microscope

In early instruments (back in the 1500s, when the microscope was first invented) the lens arrangement was very simple, and just one or two lenses were used. Modern microscope objective and eyepiece lenses are often compound in themselves – that is, made up of several different lenses, precisely aligned and mounted together to produce a high-quality image.

Compound microscopes are also commonly known by several other names, such as biological microscopes, optical microscopes and brightfield (or bright field) microscopes.


Compound Microscope Uses


Compound microscopes are used extensively in many fields. Perhaps the most common and most familiar is health care, where they are used to examine blood and tissue samples, for example, or to examine biological cultures for bacteria and other microorganisms.

Because it is possible to build simple, economical but relatively rugged compound microscopes, this is also the type of instrument most often used to introduce children and students to the world of microscopy. It is also the type normally found in school classrooms and laboratories – though more advanced and elaborate instruments are also widely used at higher levels of education.


Basic Structure


Most compound microscopes are designed and built with this basic structure:

  • A base or stand provides a stable base for the whole instrument.

  • A stage is provided, to securely hold the object to be viewed.

  • A light source of some type is included, the most recent innovation being LED illumination, all of our microscopes now come with LED, arranged in such a way that it will provide enough light for the viewer to clearly see the object viewed. In most basic compound microscopes, objects are viewed using light passed through the object, from below. For the reason, the light source is ordinarily positioned below the stage, arranged so that it can direct light upward through an opening in the stage, and on through the object being viewed. The term “bright field microscope” comes from this most common lighting arrangement – the term refers to the brightly-lit field of view seen when the observer looks through the instrument’s eyepiece.

  • An objective lens is positioned above the stage. Many microscopes offer the user several different objective lenses, of different magnifications. In such instruments, the objectives are normally mounted on a turret, allowing the user to rotate the desired lens into position for viewing, even changing from one objective (and magnification) to another, without having to move the object being viewed.

  • An eyepiece is mounted above the objective lens. Ordinarily there is an enclosed tube connecting the objective and eyepiece; the tube arrangement normally also allows the user to substitute one eyepiece for another.

Again, these are just the basic elements of a compound microscope. There are many, many options available for each, all to suit a particular instrument’s purpose and uses.

Compound Microscope Common Options

  • Magnification

Viewing magnification in most compound microscopes is the result of the combined magnifications of the objective lens and the eyepiece. For example, if the objective lens magnifies four times (4X) and the eyepiece magnifies ten times (10X), the overall magnification will be 40 times, or 40X. (4 multiplied by 10). A 100X objective coupled with a 10X eyepiece would give a 1000X magnification – which happens to be the upper limit of most common microscopes. Higher magnifications are attainable, but due to the physical limitations of available materials, and the nature of visible light itself, for most applications requiring much higher magnification, entirely different types of microscopes are used.

Semi-Plan Objectives 4x, 10x, 40x & 100x OIL

Another choice is the option of zoom magnification or fixed magnification. As the name implies, fixed magnification is unchanging. One objective and eyepiece combination produces only one degree of magnification. A microscope equipped for zoom magnification allows the viewer to smoothly change the instrument’s degree of magnification while viewing, without changing the objective lens or eyepiece. Zoom magnification requires a more elaborate system of lenses and mountings than fixed magnification, so zoom-equipped instruments are normally significantly more expensive.

  • Illumination

A compound microscope’s light source may be as simple as a mirror, mounted below the stage in a pivoting bracket that can be adjusted to reflect light up through the stage. A small electric light positioned below the stage is another common light source – such units most often use LED Illumination. Various mechanisms for focusing, filtering and otherwise controlling the light – and even the type of light – are available, for today’s microscopes’ many different and specialized uses.

  • Digital Imaging

USB3 Digital Microscope Camera

One increasingly common type of option or accessory chosen by microscope users is adding a dedicated digital microscope camera. In fact, some microscope users no longer look through an eyepiece at all; instead, all images are digitally transferred direct to a computer or monitor, these images and videos can then be saved to your computer and used for reference or shared among colleagues and posted on/or Facebook for example.


 

Our Advanced N2000m Biological Student Microscope features a modern style C frame shape offering comfortable operation, all metal construction and high specification glass DIN achromatic objective lenses with a magnification range of 40x – 1000x we recommend this microscope for use high schools, laboratories, colleges and universities.

 

The advanced binocular microscope is designed to meet the demands of modern laboratory microscopy. Our research microscopes offer the same optics as our larger professional scopes with ball bearing movements in focusing and stage systems to ensure long life.

Designed to meet the demands of modern laboratory microscopy, our research microscopes offer the same optics as our larger professional scopes with ball bearing movements in focusing and stage systems to ensure long life, reliability and accuracy.

 

The N120 Binocular Microscope offers good performance and a rich array of the most-used features all in an economical package. The N120 is also available with a Trinocular Head Standard features include wide-field 10x eyepieces, an iris-diaphragm with Abbe condenser, LED illumination system for cool, flicker-free and colour-correct viewing. Four achromatic objective lenses are standard, with semi-plan objectives available as an optional upgrade. An excellent choice for high schools, universities and veterinary applications.

 

The N120T Trinocular Microscope offers good performance and a rich array of the most-used features all in an economical package. The N120 is also available with a binocular head configuration. Standard features include wide-field 10x eyepieces, an iris-diaphragm with Abbe condenser, LED illumination system for cool, even, flicker-free and colour-correct viewing and photography, and much more. Four achromatic objective lenses are standard.

33 views0 comments

Commenti


Post: Blog2_Post
bottom of page