| 单词 | principal ray |
| 释义 | > as lemmasprincipal ray principal ray n. †(a) Perspective the straight line from the point of sight normal to the plane of delineation or to the eye (obsolete); (b) Optics a ray passing through or reflected at the centre of a lens or mirror, or passing through the centre of the entrance pupil. ΚΠ 1704 J. Harris Lexicon Technicum I. at Plane Vertical Plane, in Opticks and Perspective, is a Plain Surface which passeth along the Principal Ray, and consequently thro' the Eye, and is perpendicular to the Geometrical Plane. a1830 Encycl. Metrop. (1845) III. 454/2 On account of this property, the ray OI is called the principal ray... The principal ray would be that which entered or emerged at the summit of the curvature. 1838 Philos. Trans. (Royal Soc.) 128 387 Some have maintained..that the visible direction of an object coincides with the visual ray, or the principal ray of the pencil which flows from it to the eye. 1970 M. Born & E. Wolf Princ. Optics (ed. 4) iv. 186 There will be a ray which passes through the centre of the entrance pupil. This special ray is known as the principal ray (also the chief or the reference ray) of the pencil. 2002 E. Hecht Optics (ed. 4) iv. 266/2 One exception is the case in which the aperture stop is at the lens, so that the chief ray is, in effect, the principal ray. < as lemmas |
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