Title:
光学系及びそれを有する光学機器
Document Type and Number:
Japanese Patent JP6415142
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide an optical system that has a wide angle of view, and has lateral chromatic aberration occurring upon attaining the wide angle of view excellently corrected, and has a high optical performance over an entire screen.SOLUTION: In an optical system composed of a first lens group with negative refractive power, an aperture stop and a second lens group with positive refractive power, the second lens group has a negative lens unit. An Abbe number νp of a material of a positive lens constituting the negative lens unit and abnormal portion dispersibility thereof Δθg.F_p, an Abbe number νn of a material of a negative lens constituting the negative lens unit and abnormal portion dispersibility thereof Δθg.F_n, a focal length of the optical system f, a focal length of the negative lens unit fsg, and abnormal portion dispersibility Δθg.F with partial dispersion ratio θg.F for g-and F-lines are appropriately set, respectively.SELECTED DRAWING: Figure 1
Inventors:
Tetsuichiro Okumura
Application Number:
JP2014140327A
Publication Date:
October 31, 2018
Filing Date:
July 08, 2014
Export Citation:
Assignee:
Canon Inc
International Classes:
G02B13/04
Domestic Patent References:
| JP2000227546A | ||||
| JP5019164A | ||||
| JP2005092056A | ||||
| JP2010128145A | ||||
| JP2011186095A |
Attorney, Agent or Firm:
Yukio Takanashi