optical aspherical surface
optical aspherical surface
[′äp·tə·kəl ā′sfer·ə·kəl ′sər·fəs] (optics)
An optical surface that does not form part of a sphere, such as a paraboloidal or ellipsoidal surface.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.