Now a day’s all of us are familiar with the term “stage” and what is its purpose? Basically, it is the main place where all the action happens such as actors performing, and the story is told. The same thing happens in the microscope as well.
In a microscope, the stage is the place where the main character of the play is placed, instead of actors or storytellers we placed specimens there, which we want to observe.
In this article, we will look at what is microscope stage is and different types of stages, their function, how they differ from each other, and where you can use this different stage?
What Is Microscope Stage?
All Microscopes are designed to include a stage where the usually mounted specimen is placed for observation. Stages are offend equipped with a Stage clip or mechanical device that holds the specimen slide in its place. The mechanical device can smoothly translate the slide back and forth as well as from side to side.
In the simplest case, the Microscope possesses the plain stage that consists of a square design containing several clips on it. These clips are usually spring-loaded and just lift and hold a slide in place.
In the microscope stage, you can see one opening or hole in the center that allows light coming from the condenser to pass through the specimen.
The Sage is also Equipped with a couple of locking and stopping Control that allows the stage to be fixed in place to prevent movement after focusing your image.
However, Stages will typically ship with a rack stop feature which can be adjusted to prevent the stage from moving too close to the objective lenses. If the stage moves too close to the objective lens the lens can be easily damaged and become non-functional.
Types Of Microscope Stage And Its Function
The microscope stage can be classified or divided according to the design and the functionality of the stage. Following are the 8 types of a microscope stage according to their design and functionality.
- Mechanical Stage
- Circular Stage
- Inverted Microscope Stage
- Precision Measurement Stage
- Micromanipulator Stage
- Universal Stage
- Stereo Microscope Stage
- Electron Microscope Stage
1. Mechanical Stage
The mechanical stage is so named because slide movements are controlled by a mechanical system mounted to the stage.
The mechanical stage clamps, instead of clips, onto the slide, and movement along the X (side to side) and Y (up and down) axis of the stage is controlled by knobs that can more precisely move the slide into position.
The mechanical stage knobs allow the user to make extremely slight movements of the slide by slightly turning the knobs instead of relying on manual movements by hand.
This allows the observer to not only find the specimen quicker but to keep the specimen in the field of view as magnification increases.
There are mechanical stage attachments that can be mounted to simple stages with some slight modifications to the simple stage including removing the standard stage clips.
2. Circular Stage
The circular stage allows even more flexibility and precision than the simple and mechanical stage because it can rotate 360 degrees.
Typically, circular stages come with stage clips but there is a mechanical attachment that can be mounted to it that gives you the benefits of a mechanical stage and the benefits of 360-degree orations.
Note that some of the mechanical stage attachments can prevent the full 360-degree motion so be sure to check to make sure the attachment you get does not impede the movement too much.
The circular stage also has two centering knobs that help to ensure the specimen is completely centered under the objective lens and does not leave the field of view as the specimen is rotated and as the higher magnification objective lenses are selected.
The stage swivels on ball bearings to do require some upkeep to ensure the swivel motion is smooth and precise.
3. Inverted Microscope Stage
Inverted microscopes are configured differently than the standard upright microscope. These microscopes have the objectives placed below the stage and use several different condenser configurations to illuminate the specimen.
Tissue culture microscopes have a condenser that is mounted above the stage, while epi-illumination microscopes (metallographs and their relatives) have a substage condenser that precedes the objectives.
In both cases, the stage is slightly modified from standard stages. The inverted microscope stage is similar in its basic overall design to the mechanical stage.
Both stages have translational controls that allow the stage to be moved in both the X and Y directions. The main difference is the large stage opening that accommodates an insert on the inverted microscope stage.
The inserts are usually made of stainless steel and have openings of various sizes to allow for large differences in sample size.
For instance, with inverted tissue culture microscopes, researchers often must scan large culture flasks to observe the entire population of cells and this is much easier to accomplish when the stage insert has a large opening.
Metallography samples are also often quite large and more of their surface can be observed with the specialized inserts.
When small specimens are to be observed, an insert with a very small opening is used to support the sample for observation. Inverted microscope stages do not translate up and down. Focusing is accomplished using a translatable nosepiece that, together with the objectives, moves up and down.
4. Precision Measurement Stage
Precision measurement stages are used with a measuring microscope. The stage itself can range from 50 X 50 to 300 X 300 millimeters. These stages are typically used for quality testing purposes for components in high technology fields that require very small pieces.
These stages are usually equipped with a rotatable stage plate that allows 360-degree movement and edge detection capabilities that allow measurements to be taken from any point.
5. Micromanipulator Stage
It is often necessary to manipulate the specimen while it is being observed under the microscope. This is the case in many tissue culture and in vitro fertilization experiments as well as genetic implantation procedures that require close observation of the sample during the experiment.
The micromanipulator stage the specialized stage has two triple-axis hydraulically controlled water micromanipulators that orchestrate specimen handling in a highly accurate manner.
For Instance, a small Petri dish containing embryos is being manipulated with the control arms to monitor the pH of the solution as well as provide radioactively labeled nutrients to the embryos.
These manipulators can be adjusted to perform a wide spectrum of functions ranging from microinjection to electrochemistry experiments.
6. Universal Stage
This unwieldy-looking microscope stage permits tilting of a thin specimen at any angle for measuring the optical structure of a birefringent crystal.
Universal stages are designed to be used with special long working distance (LWD) objectives and very low magnifications usually ranging from 5X to 20X.
These stages are graduated on all 4 axes with rotation scales that are distinguished by different color codes.
The four rotating centers of the main body all rest on a common point. Two hemispherical lenses are used to sandwich the specimen between their plane surfaces with immersion oil is applied to all contact surfaces.
7. Stereo Microscope Stage
Unlike a compound light microscope where light is condensed into a cone of light and focused up through a hole in the stage, the stereo microscope stage is transparent and a bulb light source shines light directly through the transparent stage plate.
Stereo microscope stages typically do not come with a mechanical stage because specimens used under stereo microscopes are much larger and can easily be manipulated by hand.
8. Electron Microscope Stage
The electron microscope stage is nonmagnetic and is built to be used in a vacuum environment. These stages are built with a piezoelectric actuator that is used for the nano-positioning of the specimen.