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1. WO2006115262 - OPTICAL PICKUP DEVICE

Publication Number WO/2006/115262
Publication Date 02.11.2006
International Application No. PCT/JP2006/308682
International Filing Date 19.04.2006
IPC
G11B 7/135 2006.1
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation, reproducing using an optical beam at lower power; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
135Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
CPC
G11B 2007/0006
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation ; by modifying optical properties or the physical structure; , reproducing using an optical beam at lower power ; by sensing optical properties; Record carriers therefor
0003Recording, reproducing or erasing systems characterised by the structure or type of the carrier
0006adapted for scanning different types of carrier, e.g. CD & DVD
G11B 7/1353
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation ; by modifying optical properties or the physical structure; , reproducing using an optical beam at lower power ; by sensing optical properties; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
135Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
1353Diffractive elements, e.g. holograms or gratings
G11B 7/1367
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation ; by modifying optical properties or the physical structure; , reproducing using an optical beam at lower power ; by sensing optical properties; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
135Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
1365Separate or integrated refractive elements, e.g. wave plates
1367Stepped phase plates
G11B 7/13922
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation ; by modifying optical properties or the physical structure; , reproducing using an optical beam at lower power ; by sensing optical properties; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
135Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
1392Means for controlling the beam wavefront, e.g. for correction of aberration
13922passive
Applicants
  • 株式会社 ケンウッド KABUSHIKI KAISHA KENWOOD [JP]/[JP] (AllExceptUS)
  • 新造 徹 SHINZOU, Toru [JP]/[JP]
Inventors
  • 新造 徹 SHINZOU, Toru
Agents
  • 岡部 正夫 OKABE, Masao
Priority Data
2005-12433221.04.2005JP
Publication Language Japanese (ja)
Filing Language Japanese (JA)
Designated States
Title
(EN) OPTICAL PICKUP DEVICE
(FR) DISPOSITIF DE DÉTECTION OPTIQUE
(JA) 光ピックアップ装置
Abstract
(EN) An optical pickup device enables prevention of an increase of spherical aberration during tracking without needing any finite optical system. The diameters of parallel light beams (A, B, C) for the next-generation DVDs, DVDs, and CDs are limited to diameters of a, b, c (a>b>c) in accordance with the NA for each type by a light beam limiting element, the diameter of light beam B is limited to the diameter ranges of b to c and d (=0.85×c) to e (d>e>0), the diameter of the light beam C is limited to the diameter ranges of c to d and less than e. They are passed through a phase correcting element (13B) and focused on the corresponding optical recording medium signal planes by means of a common objective lens. The objective lens is so optimized that the wave front aberration to the light beam A is minimum on the signal plane of the next generation DVD. The phase correcting element (13B) has a phase correcting zones (Z1 to Z4) of diffraction optical structure exhibiting a pseudo-kinoform shape of a step constitution. The spherical aberration to the light beam B is corrected in the zones (Z1, Z3). The spherical aberration to the light beam C is corrected in the zones (Z2, Z4). The light beam A is passed through all the zones of the light beam diameter a without changing the parallel light beam state by optimizing the step heights of the zones (Z1 to Z4).
(FR) L’invention concerne un dispositif de détection optique permettant de prévenir toute augmentation de l’aberration sphérique pendant une poursuite sans devoir recourir à un quelconque système optique fini. Le diamètre des faisceaux lumineux parallèles (A, B, C) pour les DVD de la prochaine génération, les DVD et les CD actuels est limité au diamètre de a, b, c (a>b>c) conformément à la valeur NA de chaque type par un élément limiteur de faisceau lumineux, le diamètre de faisceau lumineux B est limité aux fourchettes de diamètre de b à c et d (=0,85×c) à e (d>e>0), le diamètre du faisceau lumineux C est limité aux fourchettes de diamètre de c à d et inférieur à e. Ils passent par un élément de correction de phase (13B) et sont concentrés sur les plans de signal de support d’enregistrement optiques correspondants au moyen d’une lentille d’objectif commune. La lentille d’objectif est optimisée de telle sorte que l’aberration de front d’onde par rapport au faisceau lumineux A est minimale sur le plan de signal du DVD de la prochaine génération. L’élément de correction de phase (13B) possède plusieurs zones de correction de phase (Z1 à Z4) de structure optique de diffraction de forme pseudo-cinétique de constitution de phase. L’aberration sphérique par rapport au faisceau lumineux B est corrigée dans les zones (Z1, Z3). L’aberration sphérique par rapport au faisceau lumineux C est corrigée dans les zones (Z2, Z4). Le faisceau lumineux A passe par toutes les zones du diamètre de faisceau lumineux a sans modification de l’état du faisceau lumineux parallèle en optimisant la hauteur de phase des différentes zones (Z1 à Z4).
(JA) 有限光学系を不用とし、トラッキング動作に伴う球面収差の増大を回避する光ピックアップ装置を提供する。次世代DVD 、DVD 、CD用の光ビームA、B、Cの平行光束が光束制限素子で種類毎のNAに応じた光束径a、b、c(a>b>c)に制限され、かつBは直径b~cとd( =0.85×c) ~e(d>e>0)の範囲、Cは直径c~dとe以下の範囲に制限され、位相補正素子13Bを経て共通の対物レンズにより対応する光記録媒体信号面上に集光される。対物レンズは次世代DVD の信号面上でのAの波面収差が最小となるように最適化しておく。位相補正素子13B は階段構造の擬似キノフォーム形の回折光学構造の位相補正領域Z1乃至Z4を有し、Z1、Z3でBに対し球面収差補正をし、Z2、Z4でCに対し球面収差補正をする。AはZ1乃至Z4の段差高さを最適化して光束径aの全範囲を平行光束状態のまま透過させる。
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