Title:
光学系および光学機器
Document Type and Number:
Japanese Patent JP6881602
Kind Code:
B2
Abstract:
An optical system (LS) includes an aperture stop (S), and a positive lens (L13) that is disposed farther on the object side than the aperture stop (S) is and that satisfies the following conditional expressions: ndP1+(0.01425×νdP1) < 2.12; 18.0 <νdP1 < 35.0; and 0.702 <θgFP1+(0.00316×νdP1), where ndP1 is the refractive index of the positive lens with respect to the d-line, νdP1 is the Abbe number of the positive lens with reference to the d-line, and θgFP1 is the partial dispersion ratio of the positive lens. θgFP1 is defined by the following equation: θgFP1 = (ngP1-nFP1)/(nFP1-nCP1), assuming that the refractive index of the positive lens with respect to the g-line is ngP1, the refractive index of the positive lens with respect to the F-line is nFP1, and the refractive index of the positive lens with respect to the C-line is nCP1.
Inventors:
Masashi Yamashita
Tomoki Ito
Hiroshi Watamoto
Hirofumi Yamamoto
Tetsushi Miwa
Keisuke Tsubonoya
Ayumi Makida
Ken Uehara
Tomoki Ito
Hiroshi Watamoto
Hirofumi Yamamoto
Tetsushi Miwa
Keisuke Tsubonoya
Ayumi Makida
Ken Uehara
Application Number:
JP2019558853A
Publication Date:
June 02, 2021
Filing Date:
December 15, 2017
Export Citation:
Assignee:
NIKON CORPORATION
International Classes:
G02B13/00; G02B13/02; G02B13/04; G02B15/20
Domestic Patent References:
| JP200725653A | ||||
| JP2006349948A | ||||
| JP2009280724A | ||||
| JP2017190280A |
Attorney, Agent or Firm:
Masago Onishi
Namiki Toshiaki
Namiki Toshiaki