Reproducing device

Patent metadata

Field	Value
Publication number	US-9805761-B2
Application number	US-201715455167-A
Country	US
Kind code	B2
Filing date	Mar 10, 2017
Priority date	Jul 16, 2013
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A reproducing device ( 100 ) includes (i) an optical pickup ( 6 ) for irradiating, with reproduction light, an optical disk ( 1 ) which is a super-resolution medium, (ii) an RF signal processing circuit ( 9 ) for converting, into a reproduction signal, light which reflected off optical disk ( 1 ), (iii) an i-MLSE detecting section ( 141 ) for evaluating quality of the reproduction signal, and (iv) a spherical aberration correcting section ( 142 ) for correcting a spherical aberration by using a result of evaluation of the quality of the reproduction signal.

First claim

The invention claimed is:

1. A reproducing device capable of reproducing content from an optical information recording medium in which the content is recorded in a form of a pit group including one or more pits shorter than an optical system resolution limit of the reproducing device, comprising:
an irradiation section for irradiating the optical information recording medium with reproduction light;
a conversion section for converting, into reproduction signal indicative of the content, light which reflected off the optical information recording medium;
a signal quality evaluating section for evaluating quality of the reproduction signal converted by the conversion section; and
a spherical aberration correcting section for correcting a spherical aberration caused by the irradiation section, by using a result of evaluation of the quality of the reproduction signal which quality has been evaluated by the signal quality evaluating section; wherein
the signal quality evaluating section is an i-MLSE (Integrated-Maximum Likelihood Sequence Estimation) detecting section for (a) detecting an i-MLSE which is an evaluation index for evaluating a signal characteristic of the reproduction signal and (b) evaluating quality of the reproduction signal,
it is determined whether the optical information recording medium is a super-resolution medium or a conventional medium, and
in a case where the optical information recording medium is determined to be the super-resolution medium, the optical information recording medium is irradiated with the reproduction light having reproduction power for super-resolution reproduction.

2. A reproducing device capable of reproducing content by irradiating, via an objective lens having a numerical aperture of 0.85, an optical information recording medium with reproduction light having a wavelength of 405 nm, the optical information recording medium including (a) a light transmitting layer having a surface which the reproduction light enters, (b) an information recording layer which the reproduction light reflects off so that information is reproduced, and (c) a substrate on which a pit group is provided in a scanning direction, the pit group including one or more pits shorter than 119 nm which is an optical system resolution limit of the reproducing device, the light transmitting layer, the information recording layer, and the substrate being provided in this order from a side from which the reproduction light enters, the content being recorded in the information recording layer by use of the pit group, comprising:
an irradiation section for irradiating the optical information recording medium with reproduction light;
a conversion section for converting, into reproduction signal indicative of the content, light which reflected off the optical information recording medium;
a signal quality evaluating section for evaluating quality of the reproduction signal converted by the conversion section; and
a spherical aberration correcting section for correcting a spherical aberration caused by the irradiation section, by using a result of evaluation of the quality of the reproduction signal which quality has been evaluated by the signal quality evaluating section; wherein
the signal quality evaluating section is an i-MLSE (Integrated-Maximum Likelihood Sequence Estimation) detecting section for (a) detecting an i-MLSE which is an evaluation index for evaluating a signal characteristic of the reproduction signal and (b) evaluating quality of the reproduction signal,
it is determined whether the optical information recording medium is a super-resolution medium or a conventional medium, and
in a case where the optical information recording medium is determined to be the super-resolution medium, the optical information recording medium is irradiated with the reproduction light having reproduction power for super-resolution reproduction.

Assignees

• Sharp Kk
• Memory-Tech Holdings Inc

Inventors

• Tajima Hideharu
• Yamamoto Masaki
• Yamada Hirohisa
• Naka Takayuki
• Konishi Masahito

Classifications

• G11B20/10314 Primary

  amplitude of the recorded or reproduced signal · CPC title

• G11B7/13

  Optical detectors therefor · CPC title

• G11B7/1374

  Objective lenses {(optical objectives per se G02B9/00)} · CPC title

• G11B7/0052

  involving reflectivity, absorption or colour changes · CPC title

• G11B7/0053

  Reproducing non-user data, e.g. wobbled address, prepits, BCA · CPC title