Concave mirror

…A reflecting mirror has a spherical reflective surface. There are concave mirrors, whose reflective surface is the inner surface of a sphere, and convex mirrors, whose reflective surface is the outer surface of a sphere. The straight line passing through the center of the mirror (mirror center) M and the center of the sphere (sphere center) O is called the optical axis, and light rays that are parallel to the optical axis near the optical axis and their extensions are focused almost at the focal point F. …

*Some of the terminology explanations that mention "concave mirror" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…反射面が球面である反射鏡。球面の内面を反射面とする凹面鏡concave mirrorと球面の外面を反射面とする凸面鏡convex mirrorがある。鏡面の中心(鏡心)Mと球面の中心(球心)Oを通る直線を光軸といい，光軸の近くで光軸に平行に入射した光線およびその延長線はほぼ焦点Fに集まる。…

※「concave 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