Title:
OBJECTIVE LENS SYSTEM, OBSERVATION DEVICE, EXPOSURE DEVICE, AND DEVICE MANUFACTURING METHOD
Document Type and Number:
Japanese Patent JP2020086406
Kind Code:
A
Abstract:
To provide an objective lens system which can be corrected well for chromatic aberration in a wide wavelength band including the infrared range.SOLUTION: An objective lens system is provided, comprising, in order from the object side: a first lens group having positive refractive power; a second lens group having positive refractive power as a whole, comprising a first partial lens group having negative refractive power and a second partial lens group having positive refractive power, and including at least one positive lens; and a third lens group having negative refractive power. The objective lens system satisfies conditions expressed as: 30<ν2p<50, -0.004<Δθ2p(gF)<-0.0015, -0.003<Δθ2p(ct)<0.003, where ν2p represents an Abbe number of a glass material of the at least one positive lens belonging to the second lens group, Δθ2p(gF) represents a value indicative of gF abnormal dispersibility of the glass material, and Δθ2p(Ct) represents a value indicative of Ct abnormal dispersibility of the glass material.SELECTED DRAWING: Figure 3
Inventors:
WATANABE KATSUYA
YOSHIDA MIWAKO
NONAKA ANNA
TOKUNAGA KYOYA
YOSHIDA MIWAKO
NONAKA ANNA
TOKUNAGA KYOYA
Application Number:
JP2018225826A
Publication Date:
June 04, 2020
Filing Date:
November 30, 2018
Export Citation:
Assignee:
NIKON CORP
International Classes:
G02B21/02; G03F7/20
Domestic Patent References:
| JP2014035458A | 2014-02-24 | |||
| JP2016085335A | 2016-05-19 | |||
| JP2017116845A | 2017-06-29 |
Attorney, Agent or Firm:
Nishizawa Kazumi
Kazunori Onami
Junichi Kobayashi
Kazunori Onami
Junichi Kobayashi