double-focus lens
1Lens — (l[e^]nz), n.; pl. {Lenses} ( [e^]z). [L. lens a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. {Lentil}.] (Opt.) A piece of glass, or other transparent substance, ground with two opposite… …
2Lens (optics) — For other uses, see Lens. A lens. Lenses can be used to focus light. A lens is an optical device with perfect or approximate axial symmetry which tra …
3Lens — The transparent structure inside the eye that focuses light rays onto the retina (the nerve layer that lines the back of the eye, senses light and creates impulses that go through the optic nerve to the brain). The lens was named after the lentil …
4Crossed lens — Lens Lens (l[e^]nz), n.; pl. {Lenses} ( [e^]z). [L. lens a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. {Lentil}.] (Opt.) A piece of glass, or other transparent substance, ground with two… …
5Crystalline lens — Lens Lens (l[e^]nz), n.; pl. {Lenses} ( [e^]z). [L. lens a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. {Lentil}.] (Opt.) A piece of glass, or other transparent substance, ground with two… …
6Fresnel lens — Lens Lens (l[e^]nz), n.; pl. {Lenses} ( [e^]z). [L. lens a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. {Lentil}.] (Opt.) A piece of glass, or other transparent substance, ground with two… …
7Multiplying lens — Lens Lens (l[e^]nz), n.; pl. {Lenses} ( [e^]z). [L. lens a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. {Lentil}.] (Opt.) A piece of glass, or other transparent substance, ground with two… …
8Polyzonal lens — Lens Lens (l[e^]nz), n.; pl. {Lenses} ( [e^]z). [L. lens a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. {Lentil}.] (Opt.) A piece of glass, or other transparent substance, ground with two… …
9Double image micrometer — Micrometer Mi*crom e*ter, n. [Micro + meter: cf. F. microm[ e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given… …
10Double refraction micrometer — Micrometer Mi*crom e*ter, n. [Micro + meter: cf. F. microm[ e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given… …
