公开(公告)号：EP2325841A4

公开(公告)日：2014-08-27

申请号：EP09812923

申请日：2009-09-14

Applicant: PANASONIC CORP

Inventor： SANO KOUSEI ,  KOMMA YOSHIAKI ,  HINO YASUMORI

IPC: G11B7/26 ,  G11B7/005 ,  G11B7/24

CPC classification number: G11B7/268 ,  G11B7/00375 ,  G11B2007/0013

Abstract: An optical information medium measurement method of the present invention, for measuring a degree of modulation in an optical information medium of a multilayered structure having a plurality of information layers, includes a first step of measuring the modulation degree of each layer of the optical information medium, by use of a measurement optical system, a second step of obtaining a thickness between layers of the optical information medium, a third step of obtaining a reflectance of each layer of the optical information medium, and a fourth step of converting the modulation degree of each layer, the modulation degree being measured in the first step, into a modulation degree at a reference optical system differing from the measurement optical system, based on a value indicative of the thickness between layers, the thickness being obtained in the second step, and a value indicative of the reflectance of each layer, the reflectance being obtained in the third step.

公开(公告)号：EP1500956A4

公开(公告)日：2009-11-11

申请号：EP03723145

申请日：2003-04-18

Applicant: PANASONIC CORP

Inventor： SANO KOUSEI ,  KOMMA YOSHIAKI ,  WADA HIDENORI ,  YASUDA AKIHIRO

IPC: G11B7/1353 ,  G02B5/18 ,  G02B5/32 ,  G11B7/00 ,  G11B7/085 ,  G02F1/13 ,  G11B7/09 ,  G11B7/135

CPC classification number: G11B7/1275 ,  G02B5/32 ,  G11B7/1353 ,  G11B2007/0006

公开(公告)号：EP1993092A4

公开(公告)日：2009-04-01

申请号：EP07707245

申请日：2007-01-23

Applicant: PANASONIC CORP

Inventor： MATSUZAKI KEIICHI ,  KOMMA YOSHIAKI ,  TANAKA TOSHIYASU ,  SANO KOUSEI ,  WAKABAYASHI KANJI ,  WADA HIDENORI

IPC: G11B7/135

CPC classification number: G11B7/1353 ,  G11B7/1362 ,  G11B7/1376 ,  G11B7/13925 ,  G11B2007/0013

Abstract: A small optical pickup having a wide correction range of spherical aberration. The optical pickup comprises a rising mirror (4) for deflecting a light beam approximately perpendicularly and leading it toward the plane of incidence of an objective lens, a spherical aberration correction lens (2) having a curvature larger on one side than on the other side, a lens holder (9) for holding the spherical aberration correction lens (2) such that the plane of larger curvature projects partially to the rising mirror side, guide members (11, 42, 72) extending in the direction of optical axis (L) of a spherical aberration correction lens (s) and having an end arranged up to the side of the plane of reflection of the rising mirror (4), and portions (15, 36, 16d) sliding along the guide members (11, 42, 72). The projecting portions of the sliding portions (15, 36, 16d) are arranged to be confined in the side face of the reflective plane of the rising mirror (4), and when the spherical aberration correction lens (2) most closely approaches the rising mirror (4), the portion of the spherical aberration correction lens projecting from the lens holder overlaps the reflective plane of the rising mirror (4).

公开(公告)号：EP2360692A4

公开(公告)日：2014-08-27

申请号：EP09831663

申请日：2009-12-03

Applicant: PANASONIC CORP

Inventor： NAKAO MASAHITO ,  HINO YASUMORI ,  KOMMA YOSHIAKI ,  YAMASAKI FUMITOMO ,  SANO KOUSEI

IPC: G11B7/24038 ,  G11B7/005 ,  G11B7/007 ,  G11B7/125 ,  G11B7/1267

CPC classification number: G11B7/005 ,  G11B7/00736 ,  G11B7/1267 ,  G11B7/24038 ,  G11B2007/0013

Abstract: An information recording medium according to the present invention includes at least three information recording layers. If the readout power of a laser beam in reading information from an information recording layer L(n) is identified by Pw(n), and if the readout power of the laser beam in reading information from an information recording layer L(n+a) is identified by Pw(n+a), then a base thickness between the information recording layers is determined so that the intensity of the light when the information recording layer L(n+a) is irradiated with a laser beam having the readout power Pw(n) becomes equal to or lower than that of the light when the information recording layer L(n+a) is irradiated with a laser beam having the readout power Pw(n+a).