How does light travel in a microscope?

Our lives are filled with all kinds of intricate details. But if you want to see the details more clearly, you can’t observe them with the naked eye. This is when the microscope comes into its own. It can magnify very small objects hundreds or even thousands of times, in science, industry and other fields have its figure. But have you ever wondered how light passes through a microscope and reaches the sample under observation? In this article, we will explore how light travels through a microscope and how it works.

How does light travel through a microscope?

We all know that light is emitted from a light source, usually an LED lamp, and passes through a condenser mirror located below the stage, through which the light converges on the sample to be observed, so as to achieve optimal illumination, but also effectively reduce the impact of glare, the objective lens can collect light and magnify the image, and then project the image upward to the eyepiece to magnify the image again.

How does light reach the eye?

Due to the refractive properties of the lens, when light passes through the eyepiece, the magnified image is projected onto the retina of the eye. Due to the presence of photosensitive cells in the retina, their role is to convert the image into electrical impulses that are sent to the brain for processing. This is why we can see magnified samples through a microscope.

After understanding how light reaches the eye isn’t it interesting to also have a clear understanding of how magnification works. By understanding how light travels through a microscope, we can understand how light works with eyepieces, objectives, etc., and we can understand the complex ways in which the images we observe are produced.

Stereo Microscopes

Understanding the concept of magnification

Magnification is the extent to which the image we see is enlarged compared to its original size, an effect achieved mainly by the combination of the objective lens and the eyepiece, and the magnification of a microscope depends on the level of quality of the lens and the technology used in the design of the microscope. Higher magnification microscopes allow smaller details to be seen more accurately, but higher magnification is not always better, as it can lead to distorted images and make it difficult to see the object.

Observing the microscopic world through a microscope is amazing and allows us to see details that are invisible to the naked eye, but not the higher the magnification the better, it is very important to choose the right magnification according to the right object of observation.

The influence of illumination system in microscope

The illumination system is crucial in a microscope and is decisive for producing clear images. It not only increases the light needed to illuminate the sample, but also improves contrast to help see details more clearly. By adjusting the right intensity and angle of light, you can improve the effectiveness of your microscope.

What does microscope illumination do to gather light?

Microscopes focus light through a combination of various lenses. Light from the sample is collected and magnified by the eyepiece, and then further magnified and focused to the observer’s eye by the eyepiece. When in use, the image is sharpened by switching the eyepiece and objective lens with the appropriate magnification, and then adjusting the fine and coarse focus knobs to adjust the distance between the objective lens and the sample. In addition, different types of microscopes employ other mechanisms to perform re-adjustment operations on the light, such as the addition of a spotting scope. These principles may seem simple, but it is the precise arrangement and alignment of the mechanisms of these lenses that produces accurate and clear patterns.


Which microscopes are equipped with a light source?

First of all, not all microscopes are equipped with a light source. Usually, microscopes used in laboratories or academic institutions are equipped with a light source. Light sources provide better visibility of magnified objects at high resolution, and in stereo microscopes they are often equipped with led light sources, which can be used for repairing circuit boards, hand engraving, and other tasks. Of course there are microscopes that use other methods of illumination, but the optical principles are the same, they all utilize reflection, absorption and refraction to manipulate and magnify light.

How does the light source affect the quality of the image?

The light source plays an important role in the quality of the image displayed. The characteristics of the light source all have an effect on the image produced, such as the intensity of the light, the direction of light propagation and the color temperature. An even and bright light source also has a great impact on the clarity of the image. Insufficient light leads to blurred images and low contrast, which can have a significant impact on analysis and judgment. The propagation direction of the light source affects the illumination angle. The color temperature of the light source needs to be adjusted according to different samples. A mismatch in color temperature will result in color distortion of the sample image, making it difficult to accurately identify specific features.

Refractive light microscopy and transmitted light microscopy

Refractive light microscopes utilize light reflected from the sample to form an image. These microscopes are typically used to view opaque objects or reflective materials such as metallurgy and minerals.

Transmitted light microscopes utilize light passing through the sample to form an image, and are typically used to view transparent or translucent materials, such as cell walls in biology and medicine.

These two types of microscopes are differentiated by the way in which the sample interacts with the light, and each has its own advantages and limitations, and will be chosen for more specific use scenarios.

To summarize

Light is an important medium through which we observe the world with our eyes. Explore the amazing journey of light by understanding how light travels through a microscope. Understanding this knowledge can help us to reacquaint ourselves with the microscopic world and unravel the hidden secrets of a world that is invisible to the naked eye.