lens /ˈlɛnz/ 名詞
Lens n.; pl. Lenses Opt. A piece of glass, or other transparent substance, ground with two opposite regular surfaces, either both curved, or one curved and the other plane, and commonly used, either singly or combined, in optical instruments, for changing the direction of rays of light, and thus magnifying objects, or otherwise modifying vision. In practice, the curved surfaces are usually spherical, though rarely cylindrical, or of some other figure.
Note: ☞ Of spherical lenses, there are six varieties, as shown in section in the figures herewith given: viz., plano-concave; double-concave; plano-convex; double-convex; converging concavo-convex, or converging meniscus; diverging concavo-convex, or diverging meniscus.
Crossed lens Opt., a double-convex lens with one radius equal to six times the other.
Crystalline lens. Anat. See Eye.
Fresnel lens Opt., a compound lens formed by placing around a central convex lens rings of glass so curved as to have the same focus; used, especially in lighthouses, for concentrating light in a particular direction; -- so called from the inventor.
Multiplying lens or Multiplying glass Opt., a lens one side of which is plane and the other convex, but made up of a number of plane faces inclined to one another, each of which presents a separate image of the object viewed through it, so that the object is, as it were, multiplied.
Polyzonal lens. See Polyzonal.
n 1: a transparent optical device used to converge or diverge
transmitted light and to form images [syn: lense, lens
2: genus of small erect or climbing herbs with pinnate leaves
and small inconspicuous white flowers and small flattened
pods: lentils [syn: genus Lens]
3: (metaphor) a channel through which something can be seen or
understood; "the writer is the lens through which history
can be seen"
4: biconvex transparent body situated behind the iris in the
eye; it focuses light waves on the retina [syn: crystalline
5: electronic equipment that uses a magnetic or electric field
in order to focus a beam of electrons [syn: electron lens]