US 12,222,478 B2
Optical system, optical apparatus and method for manufacturing the 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. 17/636,862
Filed by Nikon Corporation, Tokyo (JP)
PCT Filed Aug. 26, 2020, PCT No. PCT/JP2020/032107
§ 371(c)(1), (2) Date Feb. 19, 2022,
PCT Pub. No. WO2021/039815, PCT Pub. Date Mar. 4, 2021.
Claims priority of application No. JP2019-157742 (JP), filed on Aug. 30, 2019.
Prior Publication US 2022/0269055 A1, Aug. 25, 2022
Int. Cl. G02B 15/14 (2006.01); G02B 13/00 (2006.01)
CPC G02B 15/145121 (2019.08) [G02B 13/006 (2013.01)] 15 Claims
OG exemplary drawing
 
1. An optical system comprising:
an aperture stop; and
a lens provided closer to an object than the aperture stop, the lens satisfying the following conditional expressions:
50.00<νdLZ<65.00,
0.545<θgFLZ≤0.5583,
−0.010<θgFLZ−(0.6418−0.00168×νdLZ)
where
νdLZ: a refractive index of the lens for d-line,
νdLZ: an Abbe number of the lens with reference to d-line, and
θgFLZ: a partial dispersion ratio of the lens, defined by a following expression when a refractive index of the lens for g-line is ngLZ, a refractive index of the lens for F-line is nFLZ, and a refractive index of the lens for C-line is nCLZ:
θgFLZ=(ngLZ−nFLZ)/(nFLZ−nCLZ).