A concave lens is also known as a divergent lens because it has the ability to diverge the beam of incoming light rays. It is curved towards the inside, it is thick on the top and bottom but thin at the center. The image produced by a concave lens is upright but is diminished in size. It is used in applications like cameras, laser devices, telescopes, etc. The concave lens can be of three types namely, plano-concave, biconcave, and concave-convex lens. In this article, we discuss the 10 uses of concave lenses.
Uses of a concave lenses
- Flashlight
- Binoculars
- Telescope
- Camera
- Eyeglasses
- Peep-holes
- CD/DVD players
- Scanners
- Phoropter
- Lighting effects
Flashlights
In flashlights, the aim is to project the light on a wider area as possible. The light produced by the bulb is diverged by the concave lens producing a wider beam of light. Some flashlights have the ability to adjust the radius of the beam by adjusting the distance of the concave lens from the bulb.
Binoculars
Binoculars enable us to view a magnified image of far-off objects and make them appear closer to us. They are made up of a combination of convex and concave lenses is used. The convex lens magnifies the object and the concave lens is used to focus the image properly.
Telescope
Telescopes work on the same principle as binoculars. Telescopes are used to view very far-off objects like planets in the solar system. They are also made up of a combination of convex and concave lenses. The convex lens is used for magnification and the concave lens as the eyepiece. You can read more about telescopes here.
Camera
Cameras use a combination of convex and concave lenses for image formation. The concave lens alone will diffract light into different directions, so it is used in combination with a convex lens. You can read this article to know about the different lenses used in cameras.
Eyeglasses
Concave lenses are to treat nearsightedness or myopia. Myopia occurs when the eye is unable to focus the image properly onto the retina. You can near objects clearly, but objects farther away are blurry, because the image is formed in front of the retina and not on the retina. So the divergent lens is used to focus the image on the retina.
Peepholes
Peepholes are used to give a panoramic view of the outside surroundings. A combination of concave and convex lenses is used to give a wide view.
CD/DVD players
CD/DVD players are based on laser technology. They contain a Laser device that uses concave lenses.
Scanners
Scanners are also based on laser technology and they have laser devices that use concave lenses.
Phoropter
A phoropter also commonly known as a refractor is a device used by eye-care professionals. A phoropter is used to manually test your vision and see how much it has to be corrected. An eye specialist changes the lenses manually and asks for your response after each change.
Lighting application
Concave lenses can be in LED lighting for special effects.
Why are concave lenses not used in microscopes?
Microscopes are used to magnify tiny objects like microorganisms, microparticles, etc. But, concave lenses diverge light and cannot be used for magnification purposes, hence they are not used in microscopes.
See also
Uses of convex lenses
