If a piece of transparent material or glass is given an appropriate shape, and if it is made possible that the parallel incident rays can either converge to a point, or they can diverge from the point. The piece of glass that is having such properties and shape is known as the lens.

Merely, a lens is molded or carefully ground a piece of the transparent material that is reflecting the light rays in such a way that image is formed. The lenses can be considered as a series of tiny refracting prisms, and each of them causes the refraction of light for making their image. When the prisms are acting together, then they are producing the brighter images focused at one point.

Types of Lenses

Nowadays, a variety of lenses are available, with different uses. Lenses are different from each other in terms of shape, and material from which they are made up of. The lenses can be categorized into two distinct types, such as converging lenses and diverging lenses. The converging lenses are identified by their shape, as their middle portion is relatively thick and lower and upper portions are thin. The diverging lens causes the diverging of light rays that are traveling parallel to the principal axis. It is also possible to identify the diverging lenses by their shape, as they are a thing across the middle section and their upper and lower edges are thick.

The double convex lens is symmetrical across both vertical and horizontal axis. Each lens that is having two faces, can be considered as originally being a part of a sphere. The thickness of the double convex lens is more across the middle section and it is the indication that it will cause the converging of light rays parallel to the principal axis. The double concave lenses are also symmetrical across the vertical and horizontal axis.

Application of Lenses

The convex lenses are used for correcting the far sight vision-related problems. The concave lenses are used for the correction of the nearsightedness. The telescopes and the compound microscopes use both convex and concave lenses. By using the combination of convex lenses, the images can be created as a blur. This problem can be corrected by using the concave eyepiece. Sometimes, the combinations of both convex and concave lenses are used in the cameras. Especially, in the lasers, the use of concave lenses is very important, as the actual ray of light is highly specific, which can cause damage to equipment. In the flashlights, concave lenses are used, where light beam causes converging for covering the large area.


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