Konica Minolta Opto, Inc.

Kunihiko Taka

Tatsuo Ohta

Katsuya Nakamura

Setsuo Tokuhiro

Shingo Nakamura

Disclosed is an objective lens used for an optical pickup apparatus to perform writing and/or reading of an optical information recording medium, comprising an antireflective film on a surface of a light source side, wherein a light flux of wavelengths including a wavelength &#x3bb;1 of 380 nm&#x2266;&#x3bb;1&#x2266;420 nm and a wavelength &#x3bb;2 of 630 nm&#x2266;&#x3bb;2&#x2266;810 nm, is condensed on the medium, a numerical aperture on the light source side with respect to the wavelength &#x3bb;1 is within a range of 0.8-0.9, and that with respect to the wavelength &#x3bb;2 is 0.7 or less, and a band of the antireflective film is within a range of 700 nm-800 nm in a state where a reflectance of a light flux perpendicularly entering a central portion of the surface in a wavelength region from 400 nm to 1200 nm is 3.0% or less.

Objective lens and optical pickup apparatus

The present invention provides an optical element including: a substrate; and an antireflection film formed on a surface of the substrate. The antireflection film includes a plurality of lower refractive index layers, and a plurality of higher refractive index layers which are layered alternately. Each of at least two of the plurality of lower refractive index layers comprises a same main component each other and comprises a side component with a different content ratio independently.

Optical element and optical pickup apparatus

An optical lens to be arranged in an optical information recording and/or reproducing apparatus includes at least one lens main body; an antireflective film arranged on a first lens surface which has the largest surface angle 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 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 wavelength &#x3bb;to wavelength &#x3bb;and the wavelength &#x3bb;is in a range of 348-460 nm.

Optical lens and information recording and reproducing device

An antireflection coating provided on an optical element which passes through at least two wavelengths of light in the wavelength range of 1300-1600 nm, wherein the antireflection coating comprises: a high refractive index layer; a low refractive index layer having a refractive index lower than a refractive index of the high refractive index layer; and a supplementary layer having a composition different from a composition of the high refractive index layer or from a composition of the low refractive index layer, and being provided adjacent to the high refractive index layer or to the low refractive index layer.

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Musashino, Japan

Kunihiko Taka