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Title:
SCANNING OPTICAL SYSTEM AND SCANNING-TYPE CONFOCAL MICROSCOPE
Document Type and Number:
WIPO Patent Application WO/2020/044410
Kind Code:
A1
Abstract:
A scanning optical system (SL) comprises: a first lens group (G1) having a negative refractive power; a second lens group (G2) having a positive refractive power; and a third lens group (G3) having a negative refractive power. At least one lens included in one of the first lens group (G1), the second lens group (G2), and the third lens group (G3) has a positive refractive power and satisfies the conditional expression νd1>80, and at least one lens included in one of the first lens group (G1), the second lens group (G2), and the third lens group (G3) has a negative refractive power, satisfies the conditional expression νd2<50, and satisfies the conditional expression hmax≥18.0[mm]. hmax is the maximum distance from the optical axis of a principal light beam defining a maximum image height among the principal light beams passing through a rear focal point of an object lens; νd1 is an Abbe number based on a d-line of the lens having a positive refractive power, and is defined by the expression νd1=(nd1-1)/(nF1-nC1) when nd1 is the refractive index relative to the d-line, nF1 is the refractive index relative to the F-line, and nC1 is the refractive index relative to the C-line; and νd2 is an Abbe number based on a d-line of the lens having a negative refractive power, and is defined by the expression νd2=(nd2-1)/(nF2-nC2) when nd2 is the refractive index relative to the d-line, nF2 is the refractive index relative to the F-line, and nC2 is the refractive index relative to the C-line.

Inventors:
YOSHIDA YUUKI (JP)
SUZUKI FUMIO (JP)
Application Number:
PCT/JP2018/031614
Publication Date:
March 05, 2020
Filing Date:
August 27, 2018
Export Citation:
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Assignee:
NIKON CORP (JP)
International Classes:
G02B21/36; G02B13/00; G02B21/06; G02B26/10
Domestic Patent References:
WO2012133623A12012-10-04
Foreign References:
JP2011128273A2011-06-30
JP2012173491A2012-09-10
JP2017102013A2017-06-08
JP2017142314A2017-08-17
Attorney, Agent or Firm:
OHNISHI, Shogo et al. (JP)
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