Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
2007-09-05
2010-06-15
Edun, Muhammad N. (Department: 2627)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S112280, C369S112030, C369S044230, C369S044370
Reexamination Certificate
active
07738347
ABSTRACT:
An optical pickup device includes:a laser source for emitting, to an optical disk, a laser beam having a wavelength λ1and a laser beam having a wavelength λ2, which is longer than the wavelength λ1;a light receiver, for receiving laser beams that are reflected by the optical disk;a beam splitter, for directing, to the light receiver, the laser beams reflected by the optical disk; andan astigmatism generation element, located between the beam splitter and the light receiver, for generating the laser beams to be used for focusing control, by designating as the front of the light receiver a focal point on one of the intersecting cross sections that include the light axes of the laser beams, and by designating as the rear of the light receiver, a focal point on the other cross section,wherein the astigmatism generation element is an optical element, which is like a Fresnel lens, whose step depth is substantially a natural number times either the wavelength λ1or the wavelength λ2.
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Japanese Office Action dated Nov. 26, 2009 with English Translation thereof.
Fukakusa Masaharu
Ono Eizo
Sato Hiroshi
Tsukamoto Mayumi
Dickinson Wright PLLC
Edun Muhammad N.
Panasonic Corporation
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