US 12,461,350 B2
Optical system, optical apparatus and method for manufacturing the optical system, and zoom optical system, optical apparatus and method for manufacturing the zoom optical system
Masashi Yamashita, Tokyo (JP); Tomoki Ito, Kawasaki (JP); Tomonori Kuribayashi, Yokohama (JP); Keigo Koida, Kawasaki (JP); Satoshi Miwa, Yokohama (JP); Yoko Komatsubara, Yokohama (JP); Katsuya Watanabe, Yokohama (JP); Azuna Nonaka, Yokohama (JP); and Ayumu Makida, Kawaguchi (JP)
Assigned to Nikon Corporation, Tokyo (JP)
Appl. No. 17/636,870
Filed by Nikon Corporation, Tokyo (JP)
PCT Filed Aug. 26, 2020, PCT No. PCT/JP2020/032104
§ 371(c)(1), (2) Date Feb. 19, 2022,
PCT Pub. No. WO2021/039812, PCT Pub. Date Mar. 4, 2021.
Claims priority of application No. 2019-157738 (JP), filed on Aug. 30, 2019; and application No. 2019-157745 (JP), filed on Aug. 30, 2019.
Prior Publication US 2022/0334365 A1, Oct. 20, 2022
Int. Cl. G02B 15/14 (2006.01)
CPC G02B 15/145523 (2019.08) 18 Claims
OG exemplary drawing
 
1. An optical system, comprising:
an aperture stop; and
a positive lens that is one of two lenses cemented to each other to form a cemented lens, the positive lens being disposed closer to an object than the aperture stop, wherein the positive lens in the cemented lens satisfies the following conditional expressions:
50.00<νdP1<65.00,
0.545<θgFP1≤0.5583, and
−0.010<θgFP1−(0.6418−0.00168×νdP1)
where
νdP1: an Abbe number of the positive lens with reference to d-line, and
θgFP1: a partial dispersion ratio of the positive lens, defined by the following expression when a refractive index of the positive lens for g-line is ngP1, a refractive index of the positive lens for F-line is nFP1, and a refractive index of the positive lens for C-line is nCP1:
θgFP1=(ngP1−nFP1)/(nFP1−nCP1).