| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a focus detector capable of removing stray light by a simple structure and enhancing focus detection accuracy. <P>SOLUTION: A focus detector 100 of phase difference system has level differences A to D between lens parts 121, 126 of a center section and lens parts 122, 123, 127, 128 of a peripheral section on the incident side and the emission side of a field lens 120. In a cross section including the optical axis L' of the focus detector and parallel to a direction P in which three openings 111 to 113 of a field mask 110 are aligned, a distance M<SB POS="POST">C</SB>between a light-shielding mask and an end part 129a<SB POS="POST">1</SB>of the level difference C on the emission side of the field lens in the optical axis direction of the focus detector is larger than a distance M<SB POS="POST">A</SB>between the field mask and an end part 124a<SB POS="POST">1</SB>of the level difference A on the incident side of the field lens in the optical axis direction of the focus detector. At the level difference C of the field lens, the lens part 126 of the center section is projected over the lens part 127 of the peripheral section. <P>COPYRIGHT: (C)2012,JPO&INPIT |
