Hitachi Maxell, Limited

Sanyo Electric Co., Ltd.

Sanyo Optec Design Co., Ltd.

Hitachi Maxwell, Ltd.

Mitsuru Ito

Yasuyuki Sugi

Mitsuhiro Miyauchi

Yuichi Sakurai

Kouji Takazawa

Yoshiyuki Nagataki

Takuya Hayashi

Naofumi Ueda

Provided is an objective lens manufactured well by using a mold and an optical pickup apparatus including the same. The objective lens of the present invention includes a first region that focuses laser beams of a BD, DVD, and CD standards, a second region that focuses the laser beams of the DVD and CD standards, and a third region that focuses the laser beams of the BD and the DVD standards are provided in this order from a center portion of the objective lens. A first annular zone step provided in the first region has a step amount larger than step amounts of annular zone steps provided in other regions.

Objective lens, optical pickup apparatus using the same, and method for manufacturing objective lens

Provided is an objective lens that allows securing of a long working distance for a laser beam with a long wavelength and has a predetermined thickness or larger, and an optical pickup apparatus including the objective lens. In an objective lens of the present invention, a first region that focuses laser beams of a BD, DVD, and CD standards, a second region that focuses the laser beams of the DVD and CD standards, and a third region that focuses the laser beams of the BD and the DVD standards are provided in this order from a center portion of the objective lens. An optical super resolution with the laser beam of the BD standard is achieved by preventing a portion of the laser beam of the BD standard transmitted through the second region from contributing to spot formation.

Objective lens and optical pick-up device using the same

An optical pickup lens for focusing a light beam from a laser light source on an optical information recording medium is a single lens. The optical pickup lens has two surfaces, and a surface Ropposite to a surface Rcloser to the laser light source has a continuous shape. When the surface Rhas radii h, hand h(hhh) from an optical axis to a lens periphery, and where sags in the radii h, hand hare sag, sagand sag, and differentials in the sags are &#x394;sagsagand &#x394;sag, respectively, 0&#x3e;&#x394;sagsagand &#x394;sagsagare satisfied.

Optical pickup lens

Disclosed is an objective lens that favorably focuses multiple laser beams having different wavelengths on information recording layers of optical discs, and an optical pickup apparatus including the lens. The objective lens of the invention is provided with a first region for focusing laser beams of the BD, DVD and CD standards. The first region is provided with an annular zone step having a height calculated on the basis of a wavelength of the laser beam of the BD standard, and thus causes chromatic aberration of the laser beam of the DVD standard. This chromatic aberration corrects spherical aberration occurring due to a difference in thickness between coating layers of optical discs. In the invention, the curve surface shape of the first region is adjusted so that the BD and DVD standards can share the aberration for reducing the aberration of the laser beam of the DVD standard.

Objective lens and optical pickup apparatus using the same

An optical pickup lens for focusing a light beam from a laser light source on an optical information recording medium is a single lens. The optical pickup lens has two surfaces, and a surface Ropposite to a surface Rcloser to the laser light source has a continuous shape. When the surface Rhas radii h, hand h(h&#x3c;h&#x3c;h) from an optical axis to a lens periphery, and where sags in the radii h, hand hare sag, sagand sag, and differentials in the sags are &#x394;sag, &#x394;sagand &#x394;sag, respectively, 0&#x3e;&#x394;sag&#x3e;&#x394;sagand &#x394;sag&#x3c;&#x394;sagare satisfied.

An optical pickup lens for focusing a light beam from a laser light source on an optical information recording medium is a single lens. The optical pickup lens has two surfaces, and a surface Ropposite to a surface Rcloser to the laser light source has a continuous shape. When the surface Rhas radii h, hand h(hhh) from an optical axis to a lens periphery, and where sags in the radii h, hand hare sag, sagand sag, and differentials in the sags are &#x394;sagsagand &#x394;sag, respectively,sagsagand &#x394;sagsagare satisfied.

An optical pickup lens for focusing a light beam from a laser light source on an optical information recording medium is a single lens. The optical pickup lens has two surfaces, and a surface Ropposite to a surface Rcloser to the laser light source has a continuous shape. When the surface Rhas radii h, hand h(h&#x3c;h&#x3c;h) from an optical axis to a lens periphery, and where sags in the radii h, hand hare sag, sagand sag, and differentials in the sags are &#x394;sag, &#x394;sagand &#x394;sag, respectively,&#x3e;&#x394;sag&#x3e;&#x394;sagand &#x394;sag&#x3c;&#x394;sagare satisfied.

An optical pickup lens includes a first surface to focus laser light for recording/playback on an optical disc, a second surface formed outside the first surface and radiated with laser light for lens tilt detection, and an antireflection coating to transmit the laser light for recording/playback, the antireflection coating being continuously formed on the first surface and a second surface.

Optical pickup lens capable of detecting the tilt state

An object of the invention is to provide a plastic objective lens having a good lens tilt property in both thicknesses of a two-layer disc in a used temperature range even in the plastic objective lens in which a numerical aperture (NA) is equal to or higher than 0.81, while dissolving the problem mentioned above. The objective lens includes a point at which a third order comma aberration amount generated at a time of a lens tilt of the objective lens becomes equal to a third order comma aberration amount generated at a time when a disc is tilted at the same angle amount as the lens tilt angle, in a transparent board thickness which is thicker than a larger thickness of the two-layer transparent board under a room temperature (25&#xb1;3&#xb0; C.).

Objective lens

An optical pickup lens for focusing a light beam from a laser light source on an optical information recording medium is a single lens. The optical pickup lens has two surfaces, and a surface Ropposite to a surface Rcloser to the laser light source has a continuous shape. When the surface Rhas radii h, hand h(h&#x3c;h&#x3c;h) from an optical axis to a lens periphery, and where sags in the radii h, hand hare sag, sagand sag, and differentials in the sags are &#x394;sag&#x394;sagand &#x394;sag, respectively, 0&#x3e;&#x394;sag&#x3e;&#x394;sagand &#x394;sag&#x3c;&#x394;sagare satisfied.

Growing community of inventors

Ibaraki, Japan

Mitsuru Ito