WO2007063353A2 - Procédé et appareil de lecture optique pour support d'enregistrement multicouche - Google Patents

Procédé et appareil de lecture optique pour support d'enregistrement multicouche Download PDF

Info

Publication number
WO2007063353A2
WO2007063353A2 PCT/IB2005/003628 IB2005003628W WO2007063353A2 WO 2007063353 A2 WO2007063353 A2 WO 2007063353A2 IB 2005003628 W IB2005003628 W IB 2005003628W WO 2007063353 A2 WO2007063353 A2 WO 2007063353A2
Authority
WO
WIPO (PCT)
Prior art keywords
recording medium
optical pick
multilayer recording
signal
optical
Prior art date
Application number
PCT/IB2005/003628
Other languages
English (en)
Other versions
WO2007063353A3 (fr
Inventor
Eugene Levich
Sergei Magnitskii
Original Assignee
New Medium Enterprises, Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by New Medium Enterprises, Inc filed Critical New Medium Enterprises, Inc
Priority to PCT/IB2005/003628 priority Critical patent/WO2007063353A2/fr
Priority to EP05857344A priority patent/EP1994532A4/fr
Priority to TW096119058A priority patent/TW200847156A/zh
Publication of WO2007063353A2 publication Critical patent/WO2007063353A2/fr
Publication of WO2007063353A3 publication Critical patent/WO2007063353A3/fr

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording 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
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1392—Means for controlling the beam wavefront, e.g. for correction of aberration
    • G11B7/13925—Means for controlling the beam wavefront, e.g. for correction of aberration active, e.g. controlled by electrical or mechanical means
    • G11B7/13927—Means for controlling the beam wavefront, e.g. for correction of aberration active, e.g. controlled by electrical or mechanical means during transducing, e.g. to correct for variation of the spherical aberration due to disc tilt or irregularities in the cover layer thickness
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording 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
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
    • G11B7/126—Circuits, methods or arrangements for laser control or stabilisation
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording 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
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
    • G11B7/127—Lasers; Multiple laser arrays
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording 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
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
    • G11B7/127—Lasers; Multiple laser arrays
    • G11B7/1275—Two or more lasers having different wavelengths
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording 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
    • G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
    • G11B2007/0009—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage
    • G11B2007/0013—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage for carriers having multiple discrete layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording 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
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
    • G11B7/08505—Methods for track change, selection or preliminary positioning by moving the head
    • G11B7/08511—Methods for track change, selection or preliminary positioning by moving the head with focus pull-in only
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording 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
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0948—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for detection and avoidance or compensation of imperfections on the carrier, e.g. dust, scratches, dropouts
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording 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
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/095—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for discs, e.g. for compensation of eccentricity or wobble
    • G11B7/0956—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for discs, e.g. for compensation of eccentricity or wobble to compensate for tilt, skew, warp or inclination of the disc, i.e. maintain the optical axis at right angles to the disc

Definitions

  • the present invention generally concerns the principles of reading/writing the information from/on multilayer optical media and design of reading device which can realize this function.
  • Optical pickup devices and methods use recording/reading of data on a recordable plane of an optical medium having at least two recordable planes inside disk and an input plane of protection substrate of the recording/reading disk.
  • the optical pickup devices usually use a semiconductor laser beam spot focused by an objective. Exact focusing- of the spot the recordable plane is assured by special focusing servo system that utilizes focus error signal formed with the help of the said recording/reading laser beam.
  • the multi-layer optical medium contains a set of recordable or data carrying planes ⁇ separated by intermediate transparent layers-spacers. During reading from such multi-layer optical medium, some noise is present due to interference of laser beams reflected from the said recordable/data carrying planes which drastically reduces quality of reading.
  • Recording/reading involves a reading spot formed by a laser beam focused on the data surface.
  • the mentioned objective and other additional optical elements assist in creating laser beams to form focus and track errors.
  • Patent US 5,513,158 discloses the use of a piezo-ceramic deflector to form the signal of 'narrow' focus sensor.
  • the major weakness of this solution is that it requires a powerful high- voltage generator to form pulse for PZLT plate; the former includes transparent electrodes to change the plate's optical phase fast in different areas of objective pupil causing slight flicker of focus point.
  • the PZLT plate is very inefficient and requires a highly powerful generator which will create strong interference too.
  • active wobbling of micro objective focus to read from multi-layer disks. is- disclosed in Patent US 5,740,145. Focusing system is modified in such a way that the micro objective wobbles continuously along optical axis at frequency - ⁇ 0 . To form signal of 'narrow' focus, the frequency - ⁇ 0 must be > 5 kHz.
  • Patent US 6,628,589 provides a method of correcting aberrations similar to the one described above.
  • a value of data signal amplitude value serves as a sensor for correcting tilt aberrations or spherical aberrations.
  • a device based on liquid crystal cell with transparent electrodes serves as an executive unit or, to be more precise, an adaptive corrector. The cell is divided into several
  • the type and shape of the electrodes depend on the type of aberration corrected, e.g. radial tilt and spherical aberration.
  • liquid crystals Under the action of electric field, liquid crystals begin to orient along the electric field line and create a local area of changing refraction index, the shape of this area being
  • the system of automatic compensation of wave front aberrations described in the mention Patent operates in the following manner. If any beam aberration is present, the
  • FIG. 1 illustrates laser beam propagation through multilayer disk
  • FIG. 2 illustrates dependence of reflected light power PR vs. spacer thickness h
  • FIG. 3 illustrates dependence of semiconductor laser radiation wavelength vs. power of radiation (information is taken from Hitachi HL6323M6 Laser Data sheet)
  • FIG. 4. illustrates graph of power modulation of laser HL6323M6 that gives
  • FIG. 5 shows typical discriminating S -curve
  • detection FIG. 6 shows discriminating S-curve for multilayer (three layer) medium
  • FIG. 7 shows tracking unit layout
  • FIG. 8 shows graphically the degradation coefficients of frequency-contrast parameter for spherical aberration and comma.
  • FIG. 1 there is shown reflecting signal from multiplayer reflective optical medium, having two layers in the present example.
  • FIG. 1 there are two reflecting light beams, one reflecting from the layer of interest (layer to be read) I 1 - and another beam I 0 reflected from the adjacent layer (back-reflected beams).
  • a method of suppressing of interference noise is provided.
  • coherence of reading light beam should be "destroyed” or at least decreased up to appropriate levels.
  • an interference sensor e.g. an information photo receiver with low-pass filter to detect amplitude of interference-caused low frequency noise signal
  • single two-mode (multi- mode) laser with two lines of radiation X 1 and ⁇ 2 with equal intensity In accordance with still another aspect of the invention single two-mode (multi- mode) laser with two lines of radiation X 1 and ⁇ 2 with equal intensity.
  • the sensor of interference noise value and phase is required, for this purpose, one can use the method of changing wavelength ⁇ of laser radiation e.g. using frequency modulation of pumping current of laser with distributed feedback.
  • a for suppressing of interference noise that arises at a time of reproducing information from multilayer disc having multiple semi-transparent information-carrying layers high frequency pulse laser radiation might be used.
  • This method utilizes semiconductor laser and high frequency pulsed laser power source that allows fast switching (turning of/on) of output laser radiation power.
  • Interference "destroying” in that case is due to various effects. It is known that the wavelength of laser radiation is depending on power of generation, to this end fast switching of laser power provides generating several wavelengths by the laser. Also, transient processes during laser switching leads to unstable parameters of optical resonator causing generation of additional modes with different wavelengths.
  • the interference noise is suppressed due to superposition of interference patterns produced by radiation with different wavelengths on the photo receiver.
  • this invention is proposed method of suppressing of named interference by means of laser radiation wavelength high frequency shift.
  • Optical disc comprises several semi-reflective layers with information pits that are separated by plastic spacer having thickness 20...70 ⁇ m and refraction coefficient ⁇ 1,49...1,58.
  • phase thickness of spacer h it may derive follow dependence:
  • Wavelength of semiconductor laser may vary with temperature and actual power of laser generation. So, dependence of wavelength of generated light vs. output light power for laser HITACHI HL6323M6 is illustrated in FIG. 3
  • the repetition frequency of pulses should be more than highest frequency used for optical disc information transfer. For actual DVD disks (3T pits) this frequency is 36 MHz. So appropriate pulse frequency is - 100 MHz.
  • Said high frequency pulsed power source provides repeated sequence of pulses having different power. Power difference between pulses said repeated sequence consist of, leads to wavelength shift ⁇ of laser radiation generated during of pulse duration. Said wavelength shift preferably should satisfy the above-mentioned expression.
  • suppressing of interference noise might be performed by using repeated pulse sequence consist of two or more pulses having different power.
  • a method of suppressing of interference noise wherein energy E of each pulse, namely,
  • the frequency of repeated pulse sequence should be at least two times higher than highest frequency used in channel coding of storage device this method is utilized in.
  • multi-layer disks has several information layers to be distinguished and captured by focusing system
  • multilayer disc must have several S- curves each of them is corresponding to own information layer.
  • the interlayer spaces should be as small as possible.
  • S-curves corresponding to different information layer may be interlaced and focusing and tracking signal does not provide stable reproducing of information signal.
  • the challenges for reading multi-layer disks are that the servo system sensors, i.e. focus and track sensors receive both laser beams from a specific reading data layer and layers adjacent to it thereby generating significant noise and interference.
  • This HF signal is superimposed on the usual signal on photo-detector quadrant-and-exists-on-the-all-quadrants.-So-total region-of-this-HF signal-existence -is- — -10..15 micrometers, and this enables to create narrow S-curve much narrower than that based on low frequency signals.
  • HF method allows suppress influence of adjacent layers on the useful focus servo signallf multilayer disc is read, all layers reflect incident laser beam, and finally, all reflected beams are captured by photo receiver. It is clear, that beams that are reflected from adjacent to actually read layer cause distortion of useful optical response from layer to be read. But only useful beam (i.e. that reflected from read layer) is amplitude modulated by HF information signal in contrast to all other disturbing beams because of read spot is focused on the actually read layer only, and another layers are illuminated by defocused spots. To this end, pits of adjacent layers cannot be resolved by defocused spot.
  • tracking unit includes photo receiver or photo receiver matrix for High Frequency (HF) information signal, and photo receiver or photo receiver matrix for trackingng servo signal F, and photo receiver or photo receiver matrix for tracking servo signal E circuit for processing of electric signals from photo receivers or photo receiver matrices for tracking servo signals that derives tracking error signals.
  • Tracking unit -includes-two-high-pass-filters-and-detectors-of-high-frequency-signals-High-pass- filters followed by high frequency detectors are placed between photo receiver or photo receiver matrices for tracking servo signals outputs and inputs of circuit for processing of electric signals from photo receivers or photo receiver matrices for tracking servo signals.
  • optical methods to form focus error signal can be different, namely: astigmatic, full internal reflection, method of Fresnel bi-prism, method of hologram gratings, etc.
  • cut-off frequency of high pass filters f cut off might satisfy the following condition: tservo high limit — 1 cut off — tinf low limit where fse r vo h ig h l i m it - is upper limit of servo systems spectrum or/and upper limit of spectrum of radial and axial beats of spinning disc fi nf l ow l i m it - is lower limit of read information signal.
  • an optical pickup device for reading data from multi-layer disks is equipped with a beanv.phase. corrector, which allows reducing aberrations of a reading beam to an acceptable level in case of disk tilt or change in distance from an input surface to a reading data layer.
  • the suggested corrector shall enable correcting both statistical and dynamic phase aberrations of the beam's wave front occurring during reading of the spinning disk.
  • This embodiment relates to methods of constructing apparatuses for optical recording/ reading of data using optical media (particularly disks) having at least two data surfaces (layers) in the capacity of the medium separated by- thin transparent layers of plastic.
  • the laser beam focuses .on the data layer, the former being modulated by data marks (pits), and at the same time additional beams are generated for focus and tracking sensors as well as a beam aberration sensor for multiplayer disk aberration correction.
  • a data signal amplitude value may be used for correcting tilt aberrations or spherical aberrations.
  • a device based on liquid crystal cell with transparent electrodes serves as an executive unit or, to be more precise, an adaptive corrector. The cell is divided into several zones by transparent electrodes along the area of an objective input pupil. The type and shape of the electrodes depend on the type of aberration corrected, e.g. radial tilt and spherical aberration.
  • liquid crystals Under the action of electric field, liquid crystals begin to orient along the electric field line and create a local area of changing refraction index, the shape of this area being determined by the electrode configuration. Degree of the change in refraction index and so the local changes in the phase of beam's wave front depend on electric field strength, i.e. the voltage applied to the transparent electrodes.
  • a method of generating a dynamic sensor of wave front aberrations for multi-layer optical disks is proposed. It should provide: • assure generation of signal proportionate to the value of aberration;
  • FIG. 8 shows graphically the degradation coefficients of frequency-contrast parameter for spherical aberration and comma.
  • vi' T is 1,5 ⁇ 2,5 higher than the one at frequency v wr ,
  • the amplitude of 14T pits is approximately 4 times larger than that of 3T pits due to decreased ideal MTF; hence, it is these pits that generate an aberration sensor when separating averaged data signal amplitude for aberration correction.
  • Example 1 shows that the signal of 14T pits is 1,5...2,5 times less sensitive to aberrations than that of 3T pits. Therefore, to increase sensitivity of the aberration sensor, it is necessary that the input of 3T pit signal amplitude in the average amplitude of aberration sensor error signal becomes dominant. It provides: • Improving aberration compensation
  • the proposed method is such that an error signal of a system of automatic adjustment (compensation) of aberrations of recording and/or reading devices for moving optical media (particularly optical disks) is generated as defined below.
  • a high frequency data signal from an optical head photo receiver is used as an initial signal.
  • This signal goes to an amplifying correcting device which amplified the electric signal from pits, furthermore, the amplification index of the said device is larger for signals from short pits than for signals from long pits.
  • the amplitude of pulse from small pits in the resulting signal shall be amplified to a greater degree than the one from large pits; hence specific power of a signal from small pits in the resulting signal increases compared to specific power of a signal from large pits.
  • the said resulting signal is used to generate an error signal of the system of automatic adjustment (correction) of aberration.
  • the mentioned amplifying correcting device may be an amplifier, wherein the dependence of amplification coefficient on initial signal frequency is a monotone increasing function for entire working range of initial signal frequencies; e.g. the amplification coefficient may be directly proportional to the frequency of amplified signal.
  • a method of generating error signal of a system of automatic adjustment (compensation) of optical aberrations is proposed, wherein an initial signal is a high frequency signal of optical disk reading, high frequency signal being a series of electric pulse at the output of photo receiver under influence of optical radiation modulated by pits of various length located on a moving optical medium.
  • Initial signal proceeds to the input of an amplifying correcting device which amplifies the initial signal in such a way that the amplification index for pulse from short pits is larger than that for pulse from long pits.
  • amplifying correcting device may be an amplifier, wherein the dependence of amplification coefficient on initial signal frequency is a monotone increasing function for entire working range of initial signal frequencies. Also, a resulting signal of amplifying correcting device proceeds to an amplitude detector, the output signal of which proceeds to a device of generating error signal for the system of automatic aberration control (correction). It will be appreciated by persons skilled in the art that the present invention is not limited > by what has been particularly shown and described herein above. For example, An optical pick-up method and device particularly is useful for multilayer recording medium using in low reflective information layers with reflectivity les than 10% per layer and preferably 1-5 %. Rather the scope of the invention is defined by the claims that follow:

Abstract

L'invention concerne un procédé et un appareil de lecture optique pour support d'enregistrement multicouche faisant appel à une source de rayonnement de lecture, un détecteur de signal réfléchi, un système optique pour focaliser le rayonnement de lecture dans la couche de données et le détecteur de signal réfléchi, un dispositif de focalisation et de commande de suivi et une unité de suppression d'interférence de signaux réfléchis de couches.
PCT/IB2005/003628 2005-12-04 2005-12-04 Procédé et appareil de lecture optique pour support d'enregistrement multicouche WO2007063353A2 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/IB2005/003628 WO2007063353A2 (fr) 2005-12-04 2005-12-04 Procédé et appareil de lecture optique pour support d'enregistrement multicouche
EP05857344A EP1994532A4 (fr) 2005-12-04 2005-12-04 Procédé et appareil de lecture optique pour support d'enregistrement multicouche
TW096119058A TW200847156A (en) 2005-12-04 2007-05-28 Optical pick-up method and device for multilayer recording medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IB2005/003628 WO2007063353A2 (fr) 2005-12-04 2005-12-04 Procédé et appareil de lecture optique pour support d'enregistrement multicouche

Publications (2)

Publication Number Publication Date
WO2007063353A2 true WO2007063353A2 (fr) 2007-06-07
WO2007063353A3 WO2007063353A3 (fr) 2009-04-16

Family

ID=38092610

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2005/003628 WO2007063353A2 (fr) 2005-12-04 2005-12-04 Procédé et appareil de lecture optique pour support d'enregistrement multicouche

Country Status (3)

Country Link
EP (1) EP1994532A4 (fr)
TW (1) TW200847156A (fr)
WO (1) WO2007063353A2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9275671B2 (en) 2011-06-09 2016-03-01 Case Western Reserve University Optical information storage medium

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5107483A (en) * 1987-08-19 1992-04-21 Mitsubishi Denki Kabushiki Kaisha Frequency selective optical data record/regenerate apparatus
US5077719A (en) * 1987-08-28 1991-12-31 Fujitsu Limited Optical disk access system
US5526338A (en) * 1995-03-10 1996-06-11 Yeda Research & Development Co. Ltd. Method and apparatus for storage and retrieval with multilayer optical disks
US6153318A (en) * 1996-04-30 2000-11-28 Rothberg; Gerald M. Layered material having properties that are variable by an applied electric field
EP0854473B1 (fr) * 1997-01-17 2002-09-25 Matsushita Electric Industrial Co., Ltd. Tête optique et appareil pour disque optique utilisant une telle tête
AU2002241918B2 (en) * 2001-01-16 2007-01-18 Gr Intellectual Reserve, Llc Enhanced data storage and retrieval devices and systems and methods for utilizing the same
US7342869B2 (en) * 2002-07-08 2008-03-11 Sony Corporation Optical-recording medium playback apparatus and optical-recording medium, including flying optical head features

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of EP1994532A4 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9275671B2 (en) 2011-06-09 2016-03-01 Case Western Reserve University Optical information storage medium

Also Published As

Publication number Publication date
EP1994532A2 (fr) 2008-11-26
EP1994532A4 (fr) 2009-11-11
TW200847156A (en) 2008-12-01
WO2007063353A3 (fr) 2009-04-16

Similar Documents

Publication Publication Date Title
US7227819B2 (en) Optical pick-up head, optical information apparatus, and optical information reproducing method
US7768881B2 (en) Medium, apparatus, and method of recording optical-information
JP2009508287A (ja) 記録媒体にデータを記録する装置及び方法、並びに記録媒体からデータを再生する装置及び方法
US20040022152A1 (en) Information recording/reproducing apparatus
US6667947B2 (en) Optical multi-layer information recordating medium
US20090245037A1 (en) Focus Servo Method, Optical Reproducing Method, and Optical Reproducing Apparatus
JPS5971142A (ja) 光学的情報再生装置
US20050174922A1 (en) Optical head, optical recording/reproducing apparatus, and method of optical recording/reproduction utilizing the same
US7349298B2 (en) Optical disc drive including detection and correction of spherical aberration
EP1994532A2 (fr) Procédé et appareil de lecture optique pour support d'enregistrement multicouche
JP2003115109A (ja) 情報記録再生装置
JPS62236152A (ja) 光学式ピツクアツプ
US20030095485A1 (en) Radial tilt detection optical head apparatus and optical information apparatus
JP2003217142A (ja) 光ディスクフォーカスエラー検出方法および光ディスク装置
US6809996B2 (en) Optical head, optical recording/reproducing apparatus and laser module
US7623435B2 (en) Optical pickup device, and information recording and reproduction device
EP1688928B1 (fr) Dispositif de disque optique
US6665247B2 (en) Land/groove discriminating method and optical recording/reproducing apparatus employing the method
KR20050074566A (ko) 광디스크 장치 및 정보 기록 재생 방법
KR100570858B1 (ko) 디브이디 광 픽업 장치
JP2002358683A (ja) 光ピックアップ装置
KR100195082B1 (ko) 광헤드
KR100214581B1 (ko) 광픽업장치
KR100253812B1 (ko) 고밀도 광디스크용 광픽업 장치
JP4372114B2 (ja) 光ディスク装置、光ディスク、フォーカスサーボ方法およびプログラム

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase in:

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 2005857344

Country of ref document: EP