A converging lens , in general and particularly for use in the visible wavelength range, also called a collimator lens , convex lens or positive lens , is a spherically ground lens with positive refractive power . Light incident in parallel is collected in its focal plane . Specifically, light incident parallel to the optical axis is focused at the focal point . For X-ray optics , where materials have a negative refractive power, concave lenses have the property of a converging lens.
Lenses are the most important component of optical systems and are used, for example, for camera lenses , microscope and telescope lenses and the associated eyepieces . The light of different wavelengths is refracted to different degrees by simple glass lenses , which results in imaging errors . This chromatic aberration can be compensated for by combining it with lenses with a different refractive power .
- Magnifying glass ( magnifying glass )
- Glasses against farsightedness
- simple photo lens
- simple telescope objective
- Part of microscopes
Converging lenses can be cast or ground in three shapes: biconvex (curved outwards on both sides), plano-convex (one side flat, the other curved outwards, e.g. with card magnifiers) or concave-convex (one side inward, the other curved outwards).
The latter are also called meniscus lenses (menisci) and are used for most glasses. As a converging lens, they have a cross-section similar to a crescent moon, with the convex side being more curved than the concave (conversely, it would be a diverging lens ). They are often used in multi-lens camera lenses and in compound eyepieces, e.g. B. with the Mittenzwey - and wide angle eyepieces .