parabolic mirror

…Concave mirrors have properties similar to convex lenses. When f > 0, s > 0, and an object is placed outside the focal point ( s > f ), an inverted real image is obtained, and when it is placed inside ( s < f ), an erect virtual image is produced behind the mirror. Broadly speaking, concave mirrors also include those with the inner surface of an ellipsoid or paraboloid as a reflecting surface. Among these, parabolic mirrors that use a parabolic surface are used in automobile headlights and searchlights because the light emitted from the focal point becomes parallel to the optical axis after being reflected by the parabolic surface (Figure 2). Although spherical mirrors have the characteristic of being completely free of chromatic aberration, they are rarely used alone, except in the case of a life-size imaging system in which an object is placed at the center of a sphere, because of the large spherical aberration and other aberrations. …

*Some of the terminology that mentions "parabolic mirror" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…凹面鏡は凸レンズに似た性質があり，f＞0,s＞0で，焦点より外側に物体を置く(s＞f)と倒立した実像が得られ，内側に置く(s＜f)と鏡のうしろ側に正立した虚像ができる。広くは回転楕円面，放物面の内側を反射面としたものも凹面鏡に含め，このうち放物面を利用した放物面鏡parabolic mirrorは，焦点から出た光が放物面で反射したのち光軸と平行になるので，自動車のヘッドライトやサーチライトなどに用いられている（図2）。　球面鏡には色収差がまったくないという特徴はあるが，球心に物体を置いた等倍結像系の場合を除き，球面収差をはじめ各種の収差が大きいので単独で用いられることは少ない。…

※「parabolic mirror」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報