| US 7,602,679 B2 | ||
| Optical lens and information recording and reproducing device | ||
| Tatsuo Ohta, Otsuki (Japan); and Kunihiko Taka, Musashino (Japan) | ||
| Assigned to Konica Minolta Opto, Inc., Tokyo (Japan) | ||
| Filed on Jul. 07, 2004, as Appl. No. 10/885,038. | ||
| Claims priority of application No. 2003-195903 (JP), filed on Jul. 11, 2003. | ||
| Prior Publication US 2005/0007934 A1, Jan. 13, 2005 | ||
| Int. Cl. G11B 7/00 (2006.01) | ||
| U.S. Cl. 369—44.23 [369/112.23] | 37 Claims |
| 1. An optical lens to be arranged in an optical information recording and/or reproducing apparatus for conducting at least
one of recording information on an optical information recording medium and reproducing information recorded on the optical
information recording medium and to converge a light flux emitted by a first laser light source with wavelength of 390 nm-420
nm onto the optical information recording medium, the optical lens comprising:
at least one lens main body;
an antireflective film arranged on a first lens surface which has the largest surface angle θ on an outer peripheral portion
in an effective radius of lens surfaces on the lens main body;
wherein for a light entering perpendicularly to a central portion of the first lens surface whose central portion has a surface
angle θ of 0 degree, a spectral reflectance of the antireflective film has one or more regions in which the spectral reflectance
is continuously 4% or below and the wavelength includes at least a part of a wavelength region of 300 to 1000 nm,
the broadest wavelength region of the one or more wavelength regions extends from a wavelength λ1 to a wavelength λ2 and
the wavelength λ1 is in a range of 348-460 nm.
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