Two types of lenses are used in a microscope. One is the objective lenses while the other is known as the ocular lens. Lenses are the main components of any microscope, without this lens we cannot be able to see the magnified images of objects this is under consideration. But in this article, we shall discuss the ocular lens, its functions and shall also explain why we use an ocular lens in the microscope.
Microscopes are being used in almost all of the science education and field. Knowing its parts would surely help to bring the best from it and saving costs in repair and replacements. The ocular lens is also named as “eyepiece”. An ocular lens, or eyepiece, is a type of lens that is used in different optical instruments such as telescopes and microscopes to magnify the things and objects with cannot be seen without a microscope, Such as microorganisms (Bacteria, Yeast). Two closet point can be seen by this lens. This lens is the closest to our eye, while people look at objects through a microscope and its magnification power is much higher than the Objective lens.
Functions of Ocular Lens
Here we shall discuss the function of the ocular lens in the microscope.
- The eyepiece or ocular lens is a cylinder containing two or more lenses placed inside a cylindrical housing called a barrel. The role of these lenses is to bring the image into focus for the eye.
- As we know, eye produces actual imaging but eyepiece or ocular lens have some field lenses. These field lenses are used to expand the field of view. If this field lens is placed in the intermediate image plane, it does not affect the magnification of the image.
- The eyepiece or ocular lens is inserted on the top end of the body tube. These lenses are replaceable and can be replaced according to the magnification required for the image.
- The most common magnification power of the ocular lens is 5x or 10x. But sometimes it may be 15x or 20x.
- The main function of the ocular lens in a microscope is magnification. It magnifies the specimen image.
- The objective lens collects the light and brings to focus to create an image. The ocular lens is placed near the focal point of this objective lens to magnify the image. The power of magnification depends upon the focal length of the ocular lens.
- Also, the image can be focused by moving the ocular lens nearer or further from the specimen or objective.
- The ocular lens also plays an important role in reducing aberrations of specimen created by objective.
- In visual observation, an eyepiece or optical lens is used to produce a secondarily enlarged virtual image.
- In some high-performance microscopes, the optical configuration of the eyepiece and objective lens is matched to get a better result of optical performance.
- Sometimes an ocular lens can be fitted with markers, scales and crosshairs in such a way that the image of these insertions can be superimposed on the image of the specimen.
Importance of Ocular Lens
The ocular lens has great importance in the medical and microscopy field because without this lens we couldn’t be able to see micro-objects. Scientistsand Engineers did this great invention because of the use of this lens in a microscope.
Conclusion
It is now cleared that the ocular lens is used to increase the size of micro-objects. The ocular lens or Eyepiece is a most wonderful invention because it enables us to see those objects and organisms which we cannot see with our naked eye. Shortly, the ocular lens is just like the lens of our eye but high 500X times more magnification power than our eye.
