back lens
31contact lens — one of a pair of small plastic disks that are held in place over the cornea by surface tension and correct vision defects inconspicuously. Cf. hard lens, intraocular lens, soft lens. [1885 90] * * * Thin artificial lens worn on the surface of the …
32Kerr-lens modelocking — (KLM) is a method of modelocking lasers via a nonlinear optical process known as the optical Kerr effect . This method allows the generation of pulses of light with a duration as short as a few femtoseconds.The optical Kerr effect is a process… …
33Field lens — Field Field (f[=e]ld), n. [OE. feld, fild, AS. feld; akin to D. veld, G. feld, Sw. f[ a]lt, Dan. felt, Icel. fold field of grass, AS. folde earth, land, ground, OS. folda.] 1. Cleared land; land suitable for tillage or pasture; cultivated ground; …
34Parfocal lens — A parfocal lens is a lens that stays in focus when magnification/focal length is changed. There is inevitably some amount of focus error, but small enough not to be considered significant.MicroscopyParfocal microscope objectives stay in focus… …
35Battle of Lens — Infobox Military Conflict conflict=Battle of Lens partof=the Thirty Years War caption=The Battle of Lens . Contemporary illustration, oil on canvas. date=20 August 1648 place=between Grenay and Liévin, west of Lens, Pas de Calais, France… …
36Intraocular lens — The clouded (cataractous) lens is best removed in its entirety by surgery and replaced with an intraocular lens (IOL) made of plastic, an operation that takes about an hour and usually does not need hospitalization. Cataract surgery was first… …
37Dialyte lens — A dialyte lens (sometimes called a dialyt[1]) is a compound lens design that corrects optical aberrations where the lens elements are widely air spaced.[2] The design is used to save on the amount of glass used for specific elements or where… …
38To back against the field — Field Field (f[=e]ld), n. [OE. feld, fild, AS. feld; akin to D. veld, G. feld, Sw. f[ a]lt, Dan. felt, Icel. fold field of grass, AS. folde earth, land, ground, OS. folda.] 1. Cleared land; land suitable for tillage or pasture; cultivated ground; …
39To back the field — Field Field (f[=e]ld), n. [OE. feld, fild, AS. feld; akin to D. veld, G. feld, Sw. f[ a]lt, Dan. felt, Icel. fold field of grass, AS. folde earth, land, ground, OS. folda.] 1. Cleared land; land suitable for tillage or pasture; cultivated ground; …
40Photochromic lens — Photochromic lenses are lenses that darken on exposure to UV radiation. Once the UV is removed (for example by walking indoors), the lenses will gradually return to their clear state. Photochromic lenses may be made of either glass or plastic.… …
