Hitachi Maxell, Limited

Maxell, Ltd.

Hitachi Maxwell, Ltd.

Yutaka Makino

Yasuyuki Sugi

Koichiro Wakabayashi

Mitsuhiro Miyauchi

Takashi Sugiyama

Keiko Hirao

Yoshikazu Mitsui

An imaging lens system and an imaging device capable of capturing a long-distance image in a central direction of an optical axis with high resolution and capturing a neighborhood image at a wide angle. An imaging lens system includes, in order from an object side: a first lens group including at least a first lens, a second lens, and a third lens; an aperture stop (STOP); and a second lens group including two or more lens and having a positive combined power, an image side of the first lens has a concave surface, a combined focal length of the first lens and the second lens is negative, the third lens is a lens having a positive power, an object side of the first lens has an aspherical surface, and an incident-side surface (object side) of the first lens has an inflection point.

Imaging lens system and imaging device

An imaging lens system includes: in order from an object side, a first lens including a negative meniscus lens having a convex surface facing the object side, a second lens including a positive lens having a convex surface facing the object side, a third lens including a negative lens having a concave surface facing an image side, a fourth lens including a positive lens having a convex surface facing the object side, and a fifth lens including a meniscus lens having a concave surface facing the image side, in which: the imaging lens system further includes an aperture stop arranged on the object side or the image side of the second lens, and the lens surface on the image side of the third lens and the lens surface on the object side of the fourth lens are bonded to each other.

A pickup lens with a phase compensator is composed of a condenser lens and a phase compensator. At least one surface of the condenser lens has a step-like annular zone structure to compensate wavefront aberration generated when recording and reproducing data on an information recording medium having a substrate thickness of twith a laser beam having a wavelength &#x3bb;and wavefront aberration generated when recording and reproducing data on an information recording medium having a substrate thickness of twith a laser beam having a wavelength &#x3bb;. The phase compensator compensates wavefront aberration generated when recording and reproducing data on an information recording medium having a substrate thickness of twith a laser beam having a wavelength &#x3bb;

Pickup lens with phase compensator and optical pickup apparatus using the same

An optical pickup lens focuses laser beams having different wavelengths &#x3bb;and &#x3bb;on at least three kinds of optical discs. At least one side of the optical pickup lens has a concentric loop zonal structure for compensating wavefront aberration occurring when recording or reproducing an optical disc having a substrate thickness tby the laser beam having the wavelength &#x3bb;and wavefront aberration occurring when recording or reproducing an optical disc having a substrate thickness tby the laser beam having the wavelength &#x3bb;. When recording or reproducing an optical disc having a substrate thickness tby the laser beam having the wavelength &#x3bb;, a phase difference given to the laser beam having the wavelength &#x3bb;due to the concentric loop zonal structure is about 0.15&#x3bb; or smaller.

Optical pickup lens and optical pickup apparatus

An objective lens of this embodiment is used in an optical head in which a distance between a DVD laser and a CD laser is fixed. The objective lens focuses a laser beam emitted from the DVD laser on a DVD by a numerical aperture of 0.60, and focuses a laser beam emitted from the CD laser on a CD by an numerical aperture of 0.47. The wavefront aberration in design for CD is set greater than the wavefront aberration in design for DVD.

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Ibaraki, Japan

Yutaka Makino