Focus detector

Abstract

Abstract PURPOSE: To achieve the improvement in the detection accuracy of the focus control state of the main imaging optical system by adding an imaging optical system having pupil faces having conjugate relations near the intended focal plane of the main imaging optical system. CONSTITUTION: The pupil face of an imaging lens 2 and the respective pupil faces of relay lenses 3A and 3B are so set as to be put in the conjugate relation with each other by a field lens 4 and the intended focal plane F of the lens 2 and the respective detecting faces of photoelectric detectors 5A and 5B so as to be put in the conjugate relation with each other by the lenses 3A and 3B respectively. The image Ii of the object 1 is formed near the lens 4 by the lens 2 and this image Ii is formed again on the detectors 5A, 5B by the lenses 3A, 3B. At this time, the images Ia, Ib of the respective detectors are formed respectively by the luminous fluxes passing only the imaginary openings 2A, 2B of the lens 2 produced from the conjugate relations of the pupil face of the lens 2 and the respective pupil faces of the lenses 3A, 3B. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Hideo Yokota
• 👤 Kikuo Momiyama
• 👤 Tetsuo Kuwayama
• 👤 Kiyonobu Endo
• 👤 Nobuyoshi Tanaka

Bibliographic Details