A microscope has no function without its stage. The stage is where the specimen is viewed, and where the story is told.
The stage is the little aluminum or iron platform where a slide is placed, and the specimen is viewed.
This slide can be raised or lowered when it comes to observation, and the stages often include certain clips that allow the slide to stay in place while it is adjusted in order for it to be viewed.
When it comes to microscopy, the specimen is where the action happens and where the story is told, and this cannot happen without the appropriate stage.
This article will be discussing the different types of stages and their characteristics.
Different Types Of Microscopes
Before delving into the stages of microscopes, let’s highlight a few different types of these scientific apparatus.
Compound Light Microscope
Compound microscopes are some of the more common microscopes you’ll find, especially in science classrooms.
These combine lenses and light in order to view samples.
The eyepiece normally allows 10x to 15x magnification, but if more lenses are added, you can have up to 1000x magnification.
Compound light microscopes are very common for studying plant cells, bacteria, parasites, and viewing drug structures.
As these microscopes are so common, there are several models available, and you can find some that are relatively inexpensive.
Stereo Microscope
These are also known as dissecting microscopes. They allow samples to be viewed three-dimensonally as the microscope has two optical paths.
Their magnification is lower than the compound microscope, giving between 10x and 200x magnification.
However, you can also purchase a zoom variety of this microscope from a manufacturer.
These microscopes are generally used for microsurgery, looking at surfaces, and also making watches. They are also useful for watching photosynthesis taking place.
Digital Microscopes
Digital microscopes are on a whole new level as they allow you to see objects that can’t be viewed by the naked eye.
They do this by connecting the microscope to a computer with a USB cable, just as you would a mouse.
The software on the computer then shows the magnified sample. You are also able to capture still as well as moving images, and save them on the computer’s memory.
You are also able to email images over the internet. This makes sharing samples a lot easier, and allows for more connectivity within the industry.
The images obtained are also in great detail, and can be enlarged, with the only limitation being the size of the computer screen.
Pocket Microscopes
These little portable microscopes are compact but powerful.
They are great for kids and students, and scientists sometimes use them as a hand -held microscope when they are out in the field and need to examine some samples.
Their magnification can range from 25x to 100x and several models are available.
Electron Microscopes
These microscopes are very advanced, with some blasting electrons through a sample, in order to examine samples.
These microscopes allow scientists to view these samples at a nanometer size. They also use computer software in order to analyze images.
The Stage Of A Microscope
Now that you’re familiar with the different types of microscopes available, this article will now go into detail on the different stages that are attached to microscopes.
These are ultimately very important, as they are what keep the specimen in place for analysis.
Simple Stage
A simple stage is spring-loaded and has stage clips that keep the slide in place.
If the slide needs to be moved or adjusted, this must be done manually by the person’s fingers moving it up and down or slide to slide.
Due to this, under high magnification, these stages aren’t recommended as moving a slide manually is very likely to move the actual specimen.
However, there are a few locking and stopping features to keep the specimen in place after focusing on the image.
They also usually have a rack stop feature. These will prevent the stage from moving too close to the objective lens, which can ultimately damage the lens.
Mechanical Stage
The movements of the slide with a mechanical stage are controlled by a mechanical system.
The stage will clamp onto the slide and movement is controlled by certain knobs that will move the slide accordingly.
These knobs allow for the ease of slight movements to the slide, instead of having to rely on your fingers. This also will also help the observer find the specimen quicker, and be able to focus on it.
It is possible to add certain mechanical stage attachments to simple stages in order to modify the simple stage slightly if that stage is the preferred option.
Circular Stage
The circular stage is even more flexible and precise than the above options, as it can rotate 360 degrees.
Some of these circular stages, some with mechanical stage attachments, giving you the best of both worlds when it comes to flexibility and precision.
However, some of these attachments can interfere with the 360-degree rotation, so it is always best to double-check this before deciding on this stage.
There are also two knobs that are attached to this stage, and make sure that the specimen is centered perfectly under the lens.
Inverted Microscope Stage
Similar to the mechanical stage, the inverted stage can control the slide through knobs.
However, the opening in the stage is much larger with this option, so this is best suited for those who want to observe bigger samples.
The reason this kind of microscope is named ‘inverted’ is that the light source is above, and the objectives are below, which is different from a regular compound light microscope.
An inverted microscope focuses by using movement from the nosepiece and an objective lens, which means there’s no risk of clashing with the objective lens.
Precision Measurement Stage
These stages are used alongside a measuring microscope. The size of the stage can range, from around 50×50 to 300×300 millimeters.
Stages, like these, are normally used for testing specimens in high technology fields, and they are normally very small pieces.
They also regularly have stage plates that provide 360 movement as well as edge-detection features.
Micromanipulators Stage
Micromanipulator stages allow for even more precision and manipulation of the specimen.
They have two hydraulically controlled micromanopulators that are built into the stage, and these allow for more angles and areas of the specimen to be viewed.
These stages are used in several areas of science, such as IVF, genetic implantation and tissue sampling.
Universal Stage
Universal stages allow for the observation of different sizes and textures of samples.
For example, when observing rock or crystal samples, different positions and angles are required in order to observe it properly.
When this occurs, a universal stage is best suited. These are able to rotate to 360 degrees across three, four, or five axes if needed.
This gives scientists a lot more flexibility and range when it comes to observing different kinds of samples.
However, the one downside to universal stages, is that some distance is needed between the sample and objective, so the amount of magnification may be limited.
Stereo Microscope Stage
With compound light microscopes, light is shone through a cone and then is focused through a hole in the stage.
Stereo microscope stages, on the other hand, are transparent with a light bulb shining through directly to the stage plate.
Samples that are viewed through stereo microscope stages are usually bigger and can be moved by hand, so no mechanical stage is usually attached.
Electron Microscope Stage
Electron microscopes are very advanced and the stage that is used with them have a piezoelectric actuator that is meant for nano-positioning of the sample.
This is a type of precision positioning that has taken microscopy to a whole new level.
Frequently Asked Questions
What steps should you follow to get a specimen in focus?
There are a few steps you should follow in order to make sure you are focusing in on your specimen correctly.
Firstly, place your sample on the stage, and switch on the LED light. Once you’ve done this, look through the eyepiece and turn the focus knob until you notice the image has come into focus.
Then, play around with the distance between the eyepieces, so both eyes are able to view the sample correctly and comfortably.
Final Thoughts
All stages in microscopes come in different sizes and shapes, but their function is to hold the specimen in place to it can be analyzed and observed.
No matter what microscope you are using, what stage is attached, or what kind of sample you are observing, this cannot be done without a stage, so it is one of the most important features of a microscope.
As mentioned, some stages come with several features to allow for more maneuverability, and which one suits you best will depend on the specimen you are observing.
We hope this article has provided you with a good insight into the stages of microscopes.
Ever since I was a little girl, I have been fascinated by science. Every holiday I would ask for the newest science kit, and spend weeks learning with it.
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