| 释义 |
dioptre
dioptre (daɪˈɒptə) or dioptern (Units) a unit for measuring the refractive power of a lens: the reciprocal of the focal length of the lens expressed in metres[C16: from Latin dioptra optical instrument, from Greek, from dia- through + opsesthai to see] diˈoptral adjThesaurus| Noun | 1. | dioptre - a unit of measurement of the refractive power of a lens which is equal to the reciprocal of the focal length measured in meters; used by oculistsdiopterunit, unit of measurement - any division of quantity accepted as a standard of measurement or exchange; "the dollar is the United States unit of currency"; "a unit of wheat is a bushel"; "change per unit volume" |
Translationsdioptre
dioptre (US), diopter a unit for measuring the refractive power of a lens: the reciprocal of the focal length of the lens expressed in metres dioptre
dioptre A measure of lens power. The reciprocal of the focal length in metres. A lens of 1 m focal length has a power of 1 dioptre. A lens of 50 cm focal length has a power of 2 dioptres. One of 33.3 cm focal length has a power of 3 dioptres. Dioptres are used by opticians in preference to focal lengths because they can immediately be added together or subtracted during vision testing.dioptre1. A unit proposed by Monoyer to evaluate the refractive power of a lens or of an optical system. It is equal to the product of the refractive index in the image space and the reciprocal of the focal length in metres. (Symbol: D.) Thus a lens with a focal length (in air) of 1 m has a power of 1 D, one with a focal length of 1/2 m, has a power of 2 D, etc. 2. It is also incorrectly used to represent a unit of curvature, being equal to the reciprocal of the radius of curvature expressed in metres. See curvature of a surface; myodioptre; fundamental paraxial equation; refractive error; vergence. " > Fig. D3 Effect of an 8 Χ prism
| Table D3 Relationship between dioptres and focal length (in air) | | | focal length | | dioptre value | | (cm) | | (in) | | 0.25 | | 400 | | 157 | | 0.50 | | 200 | | 79 | | 1.00 | | 100 | | 39 | | 1.50 | | 67 | | 26 | | 2.00 | | 50 | | 20 | | 2.50 | | 40 | | 16 | | 3.00 | | 33.3 | | 13 | | 4.00 | | 25 | | 10 | | 5.00 | | 20 | | 7.9 | | 6.00 | | 16.7 | | 6.6 | | 7.00 | | 14.3 | | 5.6 | | 8.00 | | 12.5 | | 4.9 | | 9.00 | | 11.1 | | 4.4 | | 10.00 | | 10 | | 3.9 | | 12.00 | | 8.3 | | 3.3 | | 14.00 | | 7.1 | | 2.8 | | 16.00 | | 6.2 | | 2.4 | | 20.00 | | 5.0 | | 2.0 |
| Table D4 Relationship between prism dioptres and degrees | prism
dioptres (Χ) | | degrees (º) | | minutes (′) | | 1 | | 0.573º | | 0º34′ | | 2 | | 1.14º | | 1º8′ | | 3 | | 1.71º | | 1º43′ | | 4 | | 2.28º | | 2º17′ | | 5 | | 2.85º | | 2º51′ | | 6 | | 3.43º | | 3º26′ | | 7 | | 4.0º | | 4º0′ | | 8 | | 4.57º | | 4º34′ | | 9 | | 5.14º | | 5º8′ | | 10 | | 5.71º | | 5º43′ | | 15 | | 8.57º | | 8º34 |
dioptre
Synonyms for dioptrenoun a unit of measurement of the refractive power of a lens which is equal to the reciprocal of the focal length measured in metersSynonymsRelated Words |