US 2011/0299375 A1Published application

Optical pickup device and optical disc apparatus

AssigneeHitachi Media Electronics Co., Ltd.

InventorsKazuyoshi YAMAZAKI, Daisuke Tomita

Life of this patent

Estimating the term…

Loading patent…

Abstract

In a small-sized optical pickup device for enabling to obtain a stable servo-signal, as well as, a focus error signal and a tracking error signal, without receiving ill influences of stray lights from other layers, when recording/reproducing a multi-layer optical disc, a reflection light from the multi-layer optical disc is divided into plural numbers of regions by a diffraction grating. And, it is divided into at least four (4) regions, by a division line in the tangential direction of the optical disc and a division line in the radial direction thereof. Light receiving parts, for detecting either one of grating diffraction lights, i.e., a +1st dimensional grating diffraction light or a −1st dimensional grating diffraction light of a light beam entering into the at least four (4) regions, are aligned, nearly, on a straight line in the radial direction of the optical disc, and light receiving parts for detecting the other dimensional grating diffraction light are aligned, shifting, with respect to a direction nearly coincident with a tangential direction of the optical disc.

Claims26

Dependent claims

An optical pickup device, comprising:

a laser diode, which emits a laser light therefrom;
an objective lens, which is configured to irradiate the light beam emitting from said laser diode upon an optical disc;
a diffraction grating, which is configured to divide the light beam reflecting on an optical disc;
and
a photo detector including plural numbers of light receiving parts, which are configured to detect the light beams divided by said diffraction grating, wherein
said diffraction grating is divided, by a division line nearly coincident with a tangential direction of said optical disc, passing through a center of said diffraction grating, and a division line nearly coincident with a radial direction of said optical disc,
into at least four (4) grating regions, not including therein the division line nearly coincident with the radial direction of said optical disc,
light receiving parts for detecting either one, a +1st dimensional grating diffraction light or a −1st dimensional grating diffraction light of the light beam entering into at least the four (4) grating regions, not including the division line nearly coincident with the radial direction of said optical disc are aligned,
nearly on a straight line in a direction nearly coincident with the radial direction of said optical disc, and
light receiving parts for detecting the other dimensional grating diffraction light are aligned,
shifting, with respect to a direction nearly coincident with the tangential direction of said optical disc.

8 more elements

An optical pickup device, comprising:

a laser diode, which emits a laser light therefrom;
an objective lens, which is configured to irradiate the light beam emitting from said laser diode upon an optical disc;
a diffraction grating, which is configured to divide the light beam reflecting on an optical disc;
and
a photo detector including plural numbers of light receiving parts, which are configured to detect the light beams divided by said diffraction grating, wherein
said diffraction grating is divided, by a division line nearly coincident with a tangential direction of said optical disc, passing through a center of said diffraction grating, and a division line nearly coincident with a radial direction of said optical disc,
into at least four (4) grating regions, not including therein the division line nearly coincident with the tangential direction of said optical disc,
light receiving parts for detecting either one, a +1st dimensional grating diffraction light or a −1st dimensional grating diffraction light of the light beam entering into at least the four (4) grating regions, not including the division line nearly coincident with the tangential direction of said optical disc are aligned,
nearly on a straight line in a direction nearly coincident with the tangential direction of said optical disc, and
light receiving parts for detecting the other dimensional grating diffraction light are aligned,
shifting, with respect to a direction nearly coincident with the radial direction of said optical disc.

8 more elements

An optical pickup device, comprising:

a laser diode, which emits a laser light therefrom;
an objective lens, which is configured to irradiate the light beam emitting from said laser diode upon an optical disc;
a diffraction grating, which is configured to divide the light beam reflecting on an optical disc;
and
a photo detector including plural numbers of light receiving parts, which are configured to detect the light beams divided by said diffraction grating, wherein
said diffraction grating has three (3) regions, a region A, a region B and a region C,
among disc diffraction lights diffracted by a track on said optical disc,
a 0th dimensional disc diffraction light enters into said region A,
the 0th and ±1st dimensional disc diffraction lights enter into said region B,
on said photo detector, reproduction signals are detected from grating diffraction lights diffracting on said regions A, B and C, and also,
at least four (4) light receiving parts for detecting either one grating diffraction light, a +1st dimensional grating diffraction light or a −1st dimensional grating diffraction light of said diffraction grating region A are aligned,
nearly, on a straight line in a direction nearly coincident with a radial direction of said optical disc, and
light receiving parts for detecting the other dimensional grating diffraction light are aligned,
shifting, with respect to a tangential direction of said optical disc.

11 more elements

An optical pickup device, comprising:

a laser diode, which emits a laser light therefrom;
an objective lens, which is configured to irradiate the light beam emitting from said laser diode upon an optical disc;
a diffraction grating, which is configured to divide the light beam reflecting on an optical disc;
and
a photo detector including plural numbers of light receiving parts, which are configured to detect the light beams divided by said diffraction grating, wherein
said diffraction grating has three (3) regions, a region A, a region B and a region C,
among disc diffraction lights diffracted by a track on said optical disc,
a 0th dimensional disc diffraction light enters into said region A,
the 0th and ±1st dimensional disc diffraction lights enter into said region B,
on said photo detector, reproduction signals are detected from grating diffraction lights diffracting on said regions A, B and C, and also,
at least four (4) light receiving parts for detecting either one grating diffraction light, a +1st dimensional grating diffraction light or a −1st dimensional grating diffraction light of said diffraction grating region B are aligned,
nearly, on a straight line in a direction nearly coincident with a tangential direction of said optical disc, and
light receiving parts for detecting the other dimensional grating diffraction light are aligned,
shifting, with respect to a radial direction of said optical disc.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/078,030Filed 1 Apr 2011
Priority: JP 2010-1295307 Jun 2010
Published: 8 Dec 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G11B 7/1353
Means for guiding the beam from the source to the record carrier or from the record carrier to the detector: diffractive elements, e.g. holograms…
G11B 7/131
Optical detectors therefor: arrangement of detectors in a multiple array
G11B 7/0901
With provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record…
G11B 7/0908
With provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record…