Title:
OPTICAL SYSTEM AND OPTICAL DEVICE HAVING THE SAME
Document Type and Number:
Japanese Patent JP2019045631
Kind Code:
A
Abstract:
To provide an optical system which has a light absorptive element with a thickness distribution and offers good optical performance.SOLUTION: An optical system comprises a plurality of lenses including an aspherical lens with an aspherical surface. A light absorptive element FE having a thickness distribution in a direction perpendicular to an optical axis of the optical system 1 is provided on the optical axis. The optical system 1 satisfies the following conditional expressions: |nG×XG/(nF×XF)|>1, 0.8≤hG/hF≤1.3, where nG represents a refractive index of the aspherical lens GE, nF represents a refractive index of the light absorptive element FE, XG represents an aspherical surface sag amount of the aspherical lens GE, XF represents an aspherical surface sag amount of the light absorptive element FE, hG represents a marginal ray height of the axial ray at the aspherical lens GE, and hF represents a marginal ray height of the axial ray at the light absorptive element FE.SELECTED DRAWING: Figure 1
Inventors:
ISHIBASHI TOMOHIKO
Application Number:
JP2017167283A
Publication Date:
March 22, 2019
Filing Date:
August 31, 2017
Export Citation:
Assignee:
CANON KK
International Classes:
G02B13/18; G02B5/00; G02B13/00; G02B13/04; G02B27/58; G03B11/00
Domestic Patent References:
| JP2017040909A | 2017-02-23 | |||
| JP2007178822A | 2007-07-12 | |||
| JP2016173398A | 2016-09-29 |
Foreign References:
| WO2016039147A1 | 2016-03-17 |
Attorney, Agent or Firm:
Takuma Abe
Sogo Kuroiwa
Sogo Kuroiwa