Cylindrical lens

A cylindrical lens is an astigmatic lens, in the form of a cylinder. Cylindrical lenses focus or wide a beam of light along a single axis. The optical behavior of cylindrical lenses corresponds to the " normal" ( spherical ) lenses. It follows that a mere cylindrical lens parallel incident light to a focal line, rather than a focal point, bundles.

Even lenses which only represent cylinder segments are referred to as cylindrical lenses.

Use

Are cylindrical lenses in the optical measurement technology used in laser scanning, laser diodes, the acousto-optics (eg, acousto-optic modulator ) and in optical data processing to focus laser radiation on a line. A further application is the shaping of the beam is typically elliptical beam profile of laser diodes into a symmetrical beam profile. Also serve this purpose Anamorphic, in which, for example, one or more cylindrical lenses are used.

In medicine, cylindrical lenses are used in the form of lenses, the cylinder of the lens to compensate for errors (see astigmatism).

As a reading can help rod-shaped, plano-convex cylindrical lenses made ​​of acrylic glass are ( read ruler ) that are with the flat side down on the text and moved line by line. Older people with low vision can so that the letters look much larger ( but slightly distorted) and simultaneously lose the newline is not so easily the line.

Widescreen cinema projectors and movie cameras contain a cylindrical lens in order to save space depict the image in widescreen format to the normal aspect ratio of the movie and in the projection to equalize again ( anamorphic processes such as CinemaScope, Panavision, Total Vision and similar ).

And Fresnel lenses may be formed as cylindrical lenses.

Various cylindrical lenses

Beam path on a convex cylindrical lens