Title:
PROJECTION LENS
Document Type and Number:
WIPO Patent Application WO/2017/204127
Kind Code:
A1
Abstract:
A projection lens LN has a lens substrate 10 and an antireflective film 20 constituted of at least eight layers formed on the surface of the lens substrate 10. The material for a first layer 21 of the antireflective film 20 counted from the air side is MgF2. The refractive indices of a second layer 22, fourth layer 24, sixth layer 26, and eighth layer 28 are 2.0 - 2.3. Material for a third layer 23, fifth layer 25, and seventh layer 27 is SiO2. The quarter wave optical film thicknesses Q1 - Q8 for the first layer 21 to eighth layer 28 for a refractive index ns for the lens substrate 10 at a design main wavelength of λ0 = 550 nm satisfy predetermined equation (1) to equation (8).
Inventors:
NAKANO YOSHIHIRO (JP)
TAKAHARA KOJI (JP)
TERAMOTO MIYUKI (JP)
TAKAHARA KOJI (JP)
TERAMOTO MIYUKI (JP)
Application Number:
PCT/JP2017/018922
Publication Date:
November 30, 2017
Filing Date:
May 19, 2017
Export Citation:
Assignee:
KONICA MINOLTA INC (JP)
International Classes:
G02B1/115; G02B13/16; G03B21/14
Foreign References:
| JP2015022187A | 2015-02-02 | |||
| JP2014164120A | 2014-09-08 | |||
| JP2007094150A | 2007-04-12 | |||
| JP2010079013A | 2010-04-08 |
Other References:
See also references of EP 3467549A4
Attorney, Agent or Firm:
SANO PATENT OFFICE (JP)
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