WO2004102550A1 - Extended focus control - Google Patents
Extended focus control Download PDFInfo
- Publication number
- WO2004102550A1 WO2004102550A1 PCT/IB2004/050641 IB2004050641W WO2004102550A1 WO 2004102550 A1 WO2004102550 A1 WO 2004102550A1 IB 2004050641 W IB2004050641 W IB 2004050641W WO 2004102550 A1 WO2004102550 A1 WO 2004102550A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- displacement
- sensor signal
- signal
- track
- values
- Prior art date
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
- G11B7/08—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
-
- 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
- G11B7/0946—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 operation during external perturbations not related to the carrier or servo beam, e.g. vibration
-
- 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
- G11B7/0908—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 for focusing 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
- G11B7/095—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
Definitions
- the invention relates to a device for scanning a track on a record carrier via a beam of radiation, the track comprising marks representing information, the device comprising a head for providing the beam and generating at least one sensor signal, the head comprising a focusing element, a focusing unit for controlling the focusing element to maintain an in-focus position for generating a focused spot on the track in dependence on a displacement signal based on the sensor signal, the displacement signal being indicative of a displacement of the focusing element with respect to an in-focus position, the sensor signal having overlapping ranges of sensor signal values for different ranges of the displacement.
- the invention further relates to a method of scanning a track on a record carrier via a beam of radiation, the track comprising marks representing information, the method comprising generating at least one sensor signal, controlling a focusing element to maintain an in-focus position for generating a focused spot on the track in dependence on a displacement signal based on the sensor signal, the displacement signal being indicative of a displacement of the focusing element with respect to an in-focus position, the sensor signal having overlapping ranges of sensor signal values for different ranges of the displacement.
- a device and method for scanning a track and reading information are known from patent US 6,314,069.
- the device has a head for providing a beam of radiation focused on a track.
- a read signal is generated for reading information represented by marks in a track on a record carrier like an optical disc.
- An error signal representing a displacement of a focusing element from an in-focus position is produced based on two detector signals from a detector. The detector signals are presumed to have a periodical characteristic relative to the displacement.
- a servo system responsive to the error signal controls the focusing element to bring the beam to the in-focus position.
- a local feedback loop is coupled to the detector signals, and the error signals (that are shifted in phase) are coupled via two periodic function generators to two multipliers, which multiply the detector signals by the output of the periodic function generators.
- the output of the multipliers is coupled to the circuit to modify the error signal.
- the object is achieved with a device as defined in the opening paragraph, characterized in that the device comprises a multitude of piecewise converters, each converter converting a range of the sensor signal values into a position signal, and selection means for selecting one of the position signals as the displacement signal based on an estimated displacement.
- the object is achieved with a method as defined in the opening paragraph, the method comprising converting a multitude of ranges of the sensor signal values into a multitude of position signals, and selecting one of the position signals as the displacement signal based on an estimated displacement.
- the effect of the piecewise converting is that relevant ranges of sensor signal values are converted by dedicated converters.
- the selection of the relevant position signal is based on the estimated displacement.
- This has the advantage that operation of the focus servo system is extended more accurately outside a substantial linear range around the in-focus position, in particular including non-linear ranges having overlapping sensor signal values.
- the invention is also based on the following recognition.
- the focusing system is usually arranged for a substantially linear working region around a nominal position. Outside the linear range, i.e. for larger displacements, the sensor signal decreases constituting inverted and relatively long tail parts of the curve; the total curve usually being called s-curve.
- the selection means comprise an estimator for determining the estimated displacement based on previous values of the displacement signal. The effect is that movement of the focusing element with respect to the track is assumed to continue from the previous samples. This has the advantage that the selection of a position signal is based on a realistic physical model of the focusing element.
- At least one of the piecewise converters has a substantially proportional relation between the range of the sensor signal values and the position signal, and at least one of the piecewise converters has a substantially inverse relation between the range of the sensor signal values and the position signal.
- the position signal provides displacement values of the focusing element outside the limited linear region of the s-curve.
- Fig. lb shows a record carrier (cross section)
- Fig. lc shows a detail of a track
- Fig. 2 shows a scanning device having a focus extension
- Fig. 3 shows a sensor signal of a focus sensor
- Fig. 4 shows a focus extension unit
- Fig. 5 shows displacement of an objective lens
- Fig. 6 shows a sensor signal
- Fig. 7a shows position signals for the tail parts of the s-curve
- Fig. 7b shows a position signal for the central part of the s-curve
- Fig. 7c shows a combination of position signals
- FIG. 8 shows a reconstructed displacement signal.
- Figure la shows a disc-shaped record carrier 11 having a track 9 and a central hole 10.
- the track 9, being the position of the series of (to be) recorded marks representing information, is arranged in accordance with a spiral pattern of turns constituting substantially parallel tracks on an information layer.
- the record carrier may be optically readable, called an optical disc, and has an information layer of a read-only or recordable type. Details about the read-only DVD disc can be found in reference: ECMA-267: 120 mm DVD - Read-Only Disc - (1997).
- Examples of a recordable disc are the CD-R and CD-RW, and writable versions of DVD, such as DVD+RW, and the high density writable optical disc using blue lasers, called Blue-ray Disc (BD).
- the information is represented on the information layer by providing optically detectable marks along the track, e.g. pits or crystalline or amorphous marks in phase change material.
- the track 9 on the recordable type of record carrier is indicated by a pre-embossed track structure provided during manufacture of the blank record carrier.
- the track structure is constituted, for example, by a pregroove 14 which enables a read/write head to follow the track during scanning.
- the track structure comprises position information, e.g. addresses.
- Figure lb is a cross-section taken along the line b-b of the record carrier 11 of the recordable type, in which a transparent substrate 15 is provided with a recording layer 16 and a protective layer 17.
- the protective layer 17 may comprise a further substrate layer, for example as in DVD where the recording layer is at a 0.6 mm substrate and a further substrate of 0.6 mm is bonded to the back side thereof.
- the pregroove 14 may be implemented as an indentation or an elevation of the substrate 15 material, or as a material property deviating from its surroundings.
- the record carrier 11 is carrying information representing digitally encoded video according to a standardized format like MPEG2.
- Figure lc shows an example of a wobble of the track.
- a detail 12 of the track 9 shows a periodic variation of the lateral position of the pregroove 14, also called wobble.
- the variations cause an additional signal to arise in auxiliary detectors, e.g. in the push-pull channel generated by partial detectors in the central spot in a head of a scanning device.
- the wobble is, for example, frequency modulated and position information is encoded in the modulation.
- a comprehensive description of the wobble and encoding information therein can be found for CD in US 4,901,300 (PHN 12.398) and US 5,187,699 (PHQ 88.002), and for the DVD+RW system in US 6,538,982 (PHN 17.323).
- Figure 2 shows a scanning device having a focus extension.
- the device is provided with means for scanning the track on record carrier 11 which include a drive unit 21 for rotating the record carrier 11, a head 22, a positioning unit (not shown) for coarsely positioning the head 22 in the radial direction on the track and a focusing unit 25 for focusing a radiation beam on the track, and a control unit 20.
- the head 22 comprises an optical system of a known type for generating the radiation beam 24 guided through optical elements focused to a radiation spot 23 on a track of the information layer of the record carrier.
- the radiation beam 24 is generated by a radiation source, e.g. a laser diode.
- the head comprises a focusing element 34, for example an objective lens, controlled by the focusing unit via an actuator for moving the focus of the radiation beam 24 along the optical axis of said beam.
- the head further comprises a tracking actuator (not shown) for fine positioning of the spot 23 in a radial direction on the center of the track.
- the tracking actuator may comprise coils for radially moving an optical element or may alternatively be arranged for changing the angle of a reflecting element.
- a detector of a usual type e.g. a four-quadrant diode
- the head 22 for generating detector signals coupled to a front-end unit 31 for generating various scanning signals, including a main scanning signal 33 and error signals 35 for tracking and focusing.
- the error signals 35 are coupled a focusing extension unit 32 to generate a displacement signal 37 which is coupled to the focus unit 25 for controlling said focusing actuators.
- the error signals 35 may also be coupled to a pre-track demodulation unit for retrieving the physical addresses and other control information from the pre-track pattern constituted by wobble modulation or pre-pits.
- the main scanning signal 33 is processed by read processing unit 30 of a usual type including a demodulator, deformatter and output unit to retrieve the information.
- the focus extension unit 32 is described below with reference to Figure 4.
- the device is provided with recording means for recording information on a record carrier of a re-writable type, for example DVD+RW.
- the recording means cooperate with the head 22 and front-end unit 31 for generating a write beam of radiation, and comprise write processing means for processing the input information to generate a write signal to drive the head 22, which write processing means comprise an input unit 27, a formatter 28 and a modulator 29.
- write processing means comprise an input unit 27, a formatter 28 and a modulator 29.
- the beam of radiation is controlled to create optically detectable marks in the recording layer.
- the marks may be in any optically readable form, e.g. in the form of areas with a reflection coefficient different from their surroundings, obtained when recording in materials such as dye, alloy or phase change material, or in the form of areas with a direction of polarization different from their surroundings, obtained when recording in magneto-optical material.
- the input unit 27 comprises compression means for input signals such as analog audio and/or video, or digital uncompressed audio/video. Suitable compression means are described for video in the MPEG standards, MPEG-1 is defined in ISO/IEC 11172 and MPEG-2 is defined in ISO/IEC 13818. The input signal may alternatively be already encoded according to such standards.
- the control unit 20 controls the recording and retrieving of information and may be arranged for receiving commands from a user or from a host computer.
- the control unit 20 is connected via control lines 26, e.g. a system bus, to the other units in the device.
- the control unit 20 comprises control circuitry, for example a microprocessor, a program memory and interfaces for performing the procedures and functions as described below.
- the control unit 20 may also be implemented as a state machine in logic circuits.
- the device has a calibration unit 36 coupled to the control unit for calibrating the focus servo system under the conditions as described below with reference to Figure 4.
- the calibrating function is implemented in a computer program for a PC having a recording unit, e.g. a DVD+RW drive.
- Figure 3 shows a sensor signal of a focus sensor. The sensor signal value in
- the linear region of the s-curve depends on the optical layout of the optical pick up unit of a drive. In a small form factor drive the linear region 39 happens to be very small (order of ⁇ 2 ⁇ m), hence this drive is very sensitive to shocks.
- the tail parts of the s-curve 38 need to be included. In the tail parts the relation between displacement and sensor signal is inverted. However in general the s-curve cannot be inverted, because a sensor output signal value may correspond to different displacements.
- the device comprises a multitude of piecewise converters. Each converter is for converting a range of the sensor signal values into a position signal, assuming the displacement is within a range corresponding to the conversion range. Further the device has a selection unit for selecting one of the position signals as the displacement signal based on an estimated displacement.
- the estimated displacement is determined by using a model of the displacements of the focusing element, for example an extrapolator that determines a velocity of the displacement based on previous values of the displacement.
- other signals are used for the estimation, e.g. signals from a separate shock sensor or signals based on the periodic nature of a rotating disc having warp or tilt.
- the estimated displacement is based on a separate displacement signal based on a total amount of reflected radiation. The total amount of reflected radiation may for example be determined by summing the sensor signals of all available partial detectors in a quadrant detector.
- Figure 4 shows a focus extension unit.
- the optical sensor 41 generates a sensor signal that depends nonlinearly on the displacement of the focusing element, for example the objective lens.
- the sensor signal is fed into each of three piecewise converters 42,43,44.
- the piecewise converters generate three candidate position signals 40 that represent the position of the objective lens.
- a selector unit 46 compares the three candidates with an estimated value and selects the signal that is closest to the estimated value provided by estimator 47.
- the estimator 47 extrapolates some samples from the past. Basically it includes a simple model of the moving focusing element, for example that during these few sample times the velocity is constant. The operation of the focus extension unit is explained with reference to Figures 5 to 8.
- the estimator calculates a next estimate based on a number of preceding samples.
- the output of the estimator at instant k is called y[k], and the input u[k].
- the estimator has a calculation based on the first and third preceding sample.
- the focus extension unit comprises a filter unit 45.
- the three candidate position signals 40 are filtered by the filter 45 to suppress noise.
- Three corresponding filtered position signals are provided to the selection unit 46 for comparing to the estimated displacement.
- a corresponding non-filtered version of the selected position signal is then passed as displacement signal 49 to the focus controller, while the filtered signal 48 is used to calculate a new estimate.
- the filtered signal might be used for the displacement signal, the non- filtered version is usually preferred because filtering incurs phase shifting, which may disturb the stability of the control loop.
- the piecewise converters 42,43,44 comprise a lookup table.
- the lookup table provides position values for a large number of sensor signal values, a different table being provided for each converter for the relevant part of the s-curve.
- the first converter 42 has a range of position values corresponding to the linear part 39 of the s-curve.
- the sensor voltages are the input values for the lookup table, while the position (or a corresponding voltage) is the output of the lookup table.
- the values in the lookup table are determined by a calibration measurement of the s-curve. The calibration measurement may be performed during design of the device, or for an individual device during manufacture.
- the piecewise converters 42,43,44 comprise a look-up table which is filled during a calibration process in the device itself.
- the focusing actuator is fed by a linearly increasing control voltage, which results in a proportional change in the position of the focusing element.
- the sensor voltage is measured.
- the measured values are subdivided in a number of ranges, one range for each converter. Within a single range there are no overlapping sensor signal values, but overlap between the ranges occurs due to the shape of the s-curve.
- the calibration process may be performed for each record carrier after insertion, and/or during use in regular intervals, for example during idle time when no user data access is required.
- Figure 5 shows displacement of an objective lens.
- FIG. 6 shows a sensor signal.
- a sensor voltage 61 is given vertically, and time horizontally.
- the corresponding displacement of the focusing element is given in Figure 5.
- the curve has a proportional relation between displacement and sensor voltage.
- the sensor signal has an inverted relation to the displacement, overlapping with the linear part.
- the sensor signal also has an inverted relation to the displacement, overlapping with the linear part.
- the sensor signal is fed into the three piecewise converters, which results in the three signals shown in Figure 7.
- Figure 7a shows position signals for the tail parts of the s-curve.
- a fist position signal 71 is produced by the third converter 44.
- a first part 72 shows a correct translation of the sensor voltage of the first part 63 of the s-curve to a displacement.
- a second position signal 74 is produced by the second converter 43.
- a last part 73 shows a correct translation of the sensor voltage of the last part 64 of the s-curve to a displacement.
- Figure 7b shows a position signal for the central part of the s-curve.
- a position signal 75 is produced by the first converter 42.
- a central part 75 shows a correct translation of the sensor voltage of the central part 62 of the s-curve to a displacement.
- Figure 7c shows a combination of position signals.
- a first part 72 of the position signal is connected to a central part 75, and continued with last part 73 of the position signals provided by the different converters.
- the selector decides which signal comes closest to the estimated value. Hence the input displacement is reconstructed by the combined signal pieces.
- Figure 8 shows a reconstructed displacement signal.
- a displacement signal 80 is reconstructed by combining the position output signals from the converters as shown in Figure 7.
- the reconstructed displacement corresponds to the input displacement shown in Figure 5.
- the invention has been mainly explained by embodiments using optical discs, the invention is also suitable for other record carriers such as rectangular optical cards, magneto-optical discs or any other type of information storage system that requires control of a focus element.
- the word 'comprising' does not exclude the presence of other elements or steps than those listed and the word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements, that any reference signs do not limit the scope of the claims, that the invention may be implemented by means of both hardware and software, and that several 'means' or 'units' may be represented by the same item of hardware or software.
- the scope of the invention is not limited to the embodiments, and the invention lies in each and every novel feature or combination of features described above.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP04732378A EP1627381B1 (en) | 2003-05-16 | 2004-05-12 | Extended focus control |
JP2006530803A JP4361090B2 (en) | 2003-05-16 | 2004-05-12 | Extended focus control apparatus and method |
DE602004007796T DE602004007796T2 (en) | 2003-05-16 | 2004-05-12 | EXTENDED FOCUS CONTROL |
US10/556,449 US7548493B2 (en) | 2003-05-16 | 2004-05-12 | Extended focus control |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP03101386.5 | 2003-05-16 | ||
EP03101386 | 2003-05-16 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2004102550A1 true WO2004102550A1 (en) | 2004-11-25 |
Family
ID=33442837
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2004/050641 WO2004102550A1 (en) | 2003-05-16 | 2004-05-12 | Extended focus control |
Country Status (8)
Country | Link |
---|---|
US (1) | US7548493B2 (en) |
EP (1) | EP1627381B1 (en) |
JP (1) | JP4361090B2 (en) |
KR (1) | KR20060006968A (en) |
CN (1) | CN100464370C (en) |
AT (1) | ATE368282T1 (en) |
DE (1) | DE602004007796T2 (en) |
WO (1) | WO2004102550A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8744572B1 (en) | 2013-01-31 | 2014-06-03 | Medronic, Inc. | Systems and methods for leadless pacing and shock therapy |
AU2015213583B2 (en) * | 2014-02-10 | 2017-11-09 | Cardiac Pacemakers, Inc. | Multi-chamber leadless pacemaker system with inter-device communication |
US9808632B2 (en) * | 2015-01-23 | 2017-11-07 | Medtronic, Inc. | Implantable medical device with dual-use communication module |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4695158A (en) * | 1984-03-02 | 1987-09-22 | Pioneer Electronic Corporation | Focus error detector |
EP1220210A2 (en) * | 2000-12-21 | 2002-07-03 | Pioneer Corporation | Optical pickup apparatus and focusing control method |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3970935A (en) * | 1975-02-18 | 1976-07-20 | Burroughs Corporation | Wide-range digital reluctance tachometer |
NL8800151A (en) | 1988-01-22 | 1989-08-16 | Philips Nv | METHOD AND APPARATUS FOR RECORDING AN INFORMATION SIGNAL |
US5187699A (en) | 1988-01-22 | 1993-02-16 | U.S. Philips Corporation | Method and apparatus for successively recording two EFM-modulated signals enabling detection of boundary condition for transitioning between signals |
DE4219311C2 (en) * | 1991-06-13 | 1996-03-07 | Sony Magnescale Inc | Displacement detector |
JPH076372A (en) | 1993-06-21 | 1995-01-10 | Matsushita Electric Ind Co Ltd | Optical pickup device and control method for its focus |
US5642340A (en) | 1993-06-23 | 1997-06-24 | Sharp Kabushiki Kaisha | Device for controlling focus of an optical disk apparatus |
US5740138A (en) * | 1994-09-06 | 1998-04-14 | Kabushiki Kaisha Toshiba | Apparatus for recording information on a primary optical disk to manufacture optical disks |
FR2731808B1 (en) * | 1995-03-14 | 1997-04-11 | Thomson Csf | OPTICAL FOCUS ADJUSTMENT SYSTEM |
US5689485A (en) | 1996-04-01 | 1997-11-18 | Discovision Associates | Tracking control apparatus and method |
US6798725B1 (en) * | 1998-10-27 | 2004-09-28 | Matsushita Electric Industrial Co., Ltd. | Wave-shaping apparatus and reproduction signal processing apparatus including the same |
JP3720203B2 (en) * | 1998-11-17 | 2005-11-24 | パイオニア株式会社 | Focus jump device |
EP1066628B1 (en) | 1999-01-25 | 2003-11-12 | Koninklijke Philips Electronics N.V. | Record carrier and apparatus for scanning the record carrier |
FR2805381B1 (en) * | 2000-02-23 | 2003-09-05 | St Microelectronics Sa | METHOD AND APPARATUS FOR CONTROLLING THE POSITIONING OF AN INCIDENT OPTICAL BEAM ON A TRACK OF A MOBILE MEDIA OF INFORMATION CONTAINED IN THE SAID TRACK, IN PARTICULAR A MULTI-FUNCTION DIGITAL DISC |
US6724561B1 (en) * | 2000-06-28 | 2004-04-20 | Storage Technology Corporation | Apparatus and method for compensating for environmental effects on media |
JP4723114B2 (en) * | 2001-05-18 | 2011-07-13 | 日立コンピュータ機器株式会社 | Focus control device and focus pull-in method |
-
2004
- 2004-05-12 AT AT04732378T patent/ATE368282T1/en not_active IP Right Cessation
- 2004-05-12 KR KR1020057021762A patent/KR20060006968A/en not_active Application Discontinuation
- 2004-05-12 CN CNB2004800133224A patent/CN100464370C/en not_active Expired - Fee Related
- 2004-05-12 WO PCT/IB2004/050641 patent/WO2004102550A1/en active IP Right Grant
- 2004-05-12 JP JP2006530803A patent/JP4361090B2/en not_active Expired - Fee Related
- 2004-05-12 DE DE602004007796T patent/DE602004007796T2/en not_active Expired - Fee Related
- 2004-05-12 EP EP04732378A patent/EP1627381B1/en not_active Not-in-force
- 2004-05-12 US US10/556,449 patent/US7548493B2/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4695158A (en) * | 1984-03-02 | 1987-09-22 | Pioneer Electronic Corporation | Focus error detector |
EP1220210A2 (en) * | 2000-12-21 | 2002-07-03 | Pioneer Corporation | Optical pickup apparatus and focusing control method |
Also Published As
Publication number | Publication date |
---|---|
EP1627381A1 (en) | 2006-02-22 |
CN100464370C (en) | 2009-02-25 |
US20070008839A1 (en) | 2007-01-11 |
DE602004007796D1 (en) | 2007-09-06 |
KR20060006968A (en) | 2006-01-20 |
ATE368282T1 (en) | 2007-08-15 |
US7548493B2 (en) | 2009-06-16 |
EP1627381B1 (en) | 2007-07-25 |
JP4361090B2 (en) | 2009-11-11 |
JP2006529047A (en) | 2006-12-28 |
DE602004007796T2 (en) | 2008-04-30 |
CN1791907A (en) | 2006-06-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP2007141369A (en) | Reproduction device, and method for adjusting spherical aberration correction value and focus bias | |
US20090154306A1 (en) | Optimizing focus crosstalk cancelling | |
US7548493B2 (en) | Extended focus control | |
US7486602B2 (en) | Tilt control for reading information | |
US7269113B2 (en) | Power correction for device for scanning a record carrier | |
JP4268132B2 (en) | Rotational speed control for recording information | |
US20070030789A1 (en) | Method and radiation source driving device for controlling radiation power | |
US20090225638A1 (en) | Recording system having improved prepit detection | |
WO2005101387A1 (en) | Walking focus control | |
US20060187807A1 (en) | Optical disc having focus offset area | |
EP1629499B1 (en) | Method for recording a lead-out on an optical disc. | |
JPH10124891A (en) | Servo signal processor and optical disk device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): BW GH GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2004732378 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2007008839 Country of ref document: US Ref document number: 10556449 Country of ref document: US |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2006530803 Country of ref document: JP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1020057021762 Country of ref document: KR Ref document number: 20048133224 Country of ref document: CN |
|
WWE | Wipo information: entry into national phase |
Ref document number: 3032/CHENP/2005 Country of ref document: IN |
|
WWP | Wipo information: published in national office |
Ref document number: 1020057021762 Country of ref document: KR |
|
WWP | Wipo information: published in national office |
Ref document number: 2004732378 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 10556449 Country of ref document: US |
|
WWG | Wipo information: grant in national office |
Ref document number: 2004732378 Country of ref document: EP |