WO2006027955A1 - 光情報装置及び情報記録/再生装置 - Google Patents
光情報装置及び情報記録/再生装置 Download PDFInfo
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- WO2006027955A1 WO2006027955A1 PCT/JP2005/015368 JP2005015368W WO2006027955A1 WO 2006027955 A1 WO2006027955 A1 WO 2006027955A1 JP 2005015368 W JP2005015368 W JP 2005015368W WO 2006027955 A1 WO2006027955 A1 WO 2006027955A1
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- light
- optical
- light receiving
- information device
- optical information
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- 230000003287 optical effect Effects 0.000 title claims abstract description 172
- 238000001514 detection method Methods 0.000 claims abstract description 18
- 201000009310 astigmatism Diseases 0.000 claims description 13
- 238000010586 diagram Methods 0.000 description 18
- 238000000034 method Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 4
- 230000010287 polarization Effects 0.000 description 4
- 230000004075 alteration Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000013507 mapping Methods 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 239000011229 interlayer Substances 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 101000606504 Drosophila melanogaster Tyrosine-protein kinase-like otk Proteins 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000008034 disappearance Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
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- 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
- G11B7/1381—Non-lens elements for altering the properties of the beam, e.g. knife edges, slits, filters or stops
-
- 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
- G11B7/0901—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 track following 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
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/13—Optical detectors therefor
- G11B7/131—Arrangement of detectors in a multiple array
-
- 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
- G11B7/1353—Diffractive elements, e.g. holograms or gratings
-
- 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
- G11B7/09—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
- G11B7/0909—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 by astigmatic methods
Definitions
- the present invention relates to an optical information apparatus and an information recording Z reproducing apparatus, in particular, an optical information apparatus for recording, reproducing or erasing information on an optical recording medium, and an optical information apparatus using the optical information apparatus.
- the present invention relates to an information recording Z reproducing apparatus for recording, reproducing or erasing information on a recording medium.
- FIG. 13 shows the configuration of a conventional optical pickup used for recording and reproduction on such an optical recording medium.
- a tracking error signal is detected by irradiating an optical recording medium with three light beams (see, for example, Patent Document 1).
- a power source 1 such as a semiconductor laser emits a linearly polarized divergent beam 70 having a wavelength ⁇ 1 of 405 nm.
- the divergent beam 70 emitted from the light source 1 is converted into parallel light by a collimator lens 53 having a focal length fl of 15 mm, and then enters the polarization beam splitter 52.
- the incident beam 70 passes through the polarizing beam splitter 52, passes through the quarter-wave plate 54 and is converted into circularly polarized light, and then converted into a convergent beam by the objective lens 56 having a focal length f2 of 2 mm.
- the light passes through the transparent substrate 41 of the recording medium 40 and is condensed on the information recording surface 40b.
- the aperture of the objective lens 56 is limited by the aperture 55, and the numerical aperture NA is 0.85.
- the thickness of the transparent substrate 41 is 0.1 mm.
- the optical recording medium 40 has an information recording surface 40b.
- the optical recording medium 40 is formed with continuous grooves serving as tracks, and the track pitch tp is 0.32 m.
- the beam 70 reflected by the information recording surface 40b passes through the objective lens 56 and the quarter-wave plate 54, is converted into linearly polarized light that is 90 degrees different from the forward path, and then is reflected by the polarizing beam splitter 52.
- the beam 70 reflected by the polarization beam splitter 52 passes through a condenser lens 59 having a focal length f3 of 30 mm, is converted into convergent light, passes through a cylindrical lens 57, and is subjected to optical detection. It enters the extractor 30.
- the beam 70 is given astigmatism when passing through the cylindrical lens 57.
- the photodetector 30 has four light receiving units 30a to 30d.
- the light receiving units 30a to 30d output current signals I30a to I30d corresponding to the amount of light received.
- the focus error (hereinafter referred to as FE) signal by the astigmatism method is obtained by (I30a + I30c)-(130 b + I30d).
- the tracking error (hereinafter referred to as TE) signal by the push-pull method is obtained by (I30a + I30d)-(I30b + I30c).
- an information signal (hereinafter referred to as RF) signal recorded on the optical recording medium 40 is obtained by I30a + I30b + I30c + I30d.
- the FE signal and TE signal are amplified and phase-compensated to a desired level, and then supplied to the actuators 91 and 92 for focus and tracking control.
- FIG. 14 shows a TE signal obtained when the beam 70 is scanned in a direction orthogonal to the track formed on the optical recording medium 40.
- Tn—4,..., ⁇ + 4 shown on the horizontal axis indicate tracks formed on the information recording surface 40b of the optical recording medium 40, and the solid line extending in the vertical direction in FIG.
- the center positions of the tracks Tn—4,..., Tn + 4 when the track pitch is uniformly formed by tp are shown.
- the track Tn-1 is formed by ⁇ ⁇ -1 and the track Tn is formed by ⁇ n at a position shifted from the position where the original tracks Tn-1 and Tn should be formed. 1 is +25 nm, and ⁇ is ⁇ 25 nm.
- the amplitude of the TE signal varies greatly.
- S1 is the minimum amplitude in the vicinity of track Tn-1
- S2 is the maximum amplitude.
- the position of the zero cross point of the TE signal is shifted from the center of each of the tracks Tn-1 and Tn.
- the shift at track Tn-1 is oftl
- the shift at track Tn is oft2. That is, the deviation oft 1 and the deviation of t2 represent the off-track amount.
- Patent Document 1 Japanese Patent Laid-Open No. 3-005927
- An object of the present invention is to provide an optical pickup head device, an optical information device, and an information reproducing method capable of reducing fluctuations in signal amplitude and recording or reproducing information with high reliability.
- an optical information device provides a predetermined information recording surface of an optical recording medium having a plurality of information recording surfaces.
- Condensing means for condensing light
- beam splitting means for splitting the light beam reflected by the optical recording medium
- a light receiving part for receiving the light beam split by the beam splitting means, and light received by the light receiving part
- a light detecting means for outputting a signal corresponding to the light quantity of the beam, and at least one of the plurality of information recording surfaces is formed with a guide groove, and all of the light receiving portions are information other than the predetermined information recording surface.
- the light beam reflected on the recording surface (hereinafter referred to as the non-light-collecting surface) is arranged in a map formed on the light detection means.
- the optical information device further includes astigmatism generating means disposed between the optical path between the converging means and the light receiving unit.
- the astigmatism generating means is preferably a cylindrical lens.
- the light detection means has a plurality of light receiving parts, and each of the plurality of light receiving parts is arranged to receive the light beam reflected from the same non-light-condensing surface.
- At least some of the plurality of light receiving units are arranged substantially adjacent to each other, and each of the light beams divided by the beam dividing unit is received by at least some of the light receiving units.
- the beam splitting means has at least first to fourth areas, and is divided by the first to fourth areas.
- the received light beam is incident on a light receiving unit that outputs a signal for generating a tracking error signal.
- the light beams divided in the first and second regions mainly include first-order diffracted light diffracted by the tracks of the optical recording medium, and the light beams divided in the third and fourth regions are optical recording media.
- the light detecting means mainly includes first to fourth light receiving parts for receiving the light beams divided in the first to fourth regions, respectively. ⁇ When the signal output from the fourth light receiving part is II ⁇ 14 and K is a real number, the tracking error signal is expressed as (11 -12)- ⁇ (14-13).
- the beam splitting means has at least first to fourth regions, and the light beams split in the first and second regions are diffracted by the tracks of the optical recording medium.
- the light beam mainly including the first-order diffracted light and divided in the third and fourth regions mainly includes the 0th-order diffracted light diffracted by the track of the optical recording medium.
- the tracking error signal is ((11 -12)- ⁇ ⁇ (14-13)), where 11 to 15 are the signals that also output the first to fifth light receiving section forces, and K and L are real numbers. Represented as L'I5.
- the beam splitting means is a diffraction grating, and a tracking error signal is generated using either the first-order diffracted light or the first-order diffracted light diffracted by the diffraction grating.
- the light receiving parts for receiving the + first-order diffracted light and the first-order diffracted light diffracted by the diffraction grating are arranged at substantially axisymmetric positions across the optical axis of the 0th-order diffracted light of the diffraction grating, respectively, and + first-order diffracted light
- a tracking error signal is generated using both of the first order diffracted light and the first order diffracted light.
- a light source that emits a light beam, a light source power, a converging unit that focuses the emitted light beam on a predetermined information recording surface of an optical recording medium having a plurality of information recording surfaces, and the light reflected by the optical recording medium
- a beam splitting unit for splitting the light beam; an aperture limiting unit disposed in the vicinity of the beam splitting unit; and a light receiving unit for receiving the light beam split by the beam splitting unit.
- Light detection means for outputting a signal according to the amount of light
- a guide groove is formed on at least one of the plurality of information recording surfaces, and the light detection means includes at least a first light receiving unit for focus control and a second light receiving unit for tracking control,
- the light receiving portion of the light is reflected on an information recording surface other than a predetermined information recording surface (hereinafter referred to as a non-condensing surface) and is outside the image formed on the light detection means by the light beam limited by the aperture limiting means. Has been placed.
- astigmatism generating means is further provided between the optical path between the converging means and the light receiving section.
- the second light receiving unit is arranged in an arrangement direction other than the direction in which the light beam is diffracted by the track of the optical recording medium with respect to the first light receiving unit.
- the arrangement direction is a direction rotated about 40 to 50 degrees with respect to the direction in which the light beam is diffracted by the track of the optical recording medium.
- the second light receiving section has a plurality of light receiving areas arranged substantially adjacent to each other, and the light beam divided by the beam splitting means is received by each of the plurality of light receiving areas.
- the beam splitting means has at least four regions, and the light beam split in the regions is incident on a second light receiving unit that outputs a signal for generating a tracking error signal.
- the beam splitting means is preferably a diffraction grating.
- An information recording Z reproducing device includes an optical information device according to any one of the above, a transfer control unit that moves the optical information device, a control unit that controls the optical information device and the transfer control unit, and an optical information device. And a recording Z reproducing means for performing at least one of information recording and reproduction on the optical recording medium, and a rotating unit for rotating the optical recording medium.
- the present invention it is possible to provide an optical information apparatus that reduces fluctuations in TE signal amplitude and records or reproduces information with high reliability.
- FIG. 1 is a diagram showing a configuration of an optical information device according to a first embodiment of the present invention.
- FIG. 2 is a diagram showing a schematic configuration of an optical pickup in the optical information device according to the first embodiment of the present invention.
- FIG. 3 is a diagram showing a configuration of a beam splitting element that constitutes the optical information device according to the first embodiment of the present invention.
- FIG. 4 A diagram showing a configuration of a photodetector constituting the optical information device according to the first embodiment of the present invention.
- FIG. 5 is a diagram showing a configuration of a photodetector constituting the optical information device according to the first embodiment of the present invention.
- FIG. 6 is a diagram showing a configuration of a photodetector that constitutes the optical information device according to the first embodiment of the present invention.
- FIG. 7 is a diagram showing a configuration of a photodetector that constitutes the optical information device according to the first embodiment of the present invention.
- FIG. 8 is a diagram showing a configuration of a photodetector that constitutes the optical information device according to the second embodiment of the present invention.
- FIG. 9 is a diagram showing a configuration of a photodetector constituting the optical information device according to the third embodiment of the present invention.
- FIG. 10 is a diagram showing a schematic configuration of an optical information device according to a fourth embodiment of the present invention.
- FIG. 11 is a diagram showing a configuration of aperture limiting means that constitutes the optical information device according to the fourth embodiment of the present invention.
- FIG. 12 is a diagram showing a configuration of a photodetector constituting the optical information device according to the fourth embodiment of the present invention.
- FIG. 13 is a diagram showing a configuration of an optical pickup head device that constitutes a conventional optical information device.
- FIG. 14 is a diagram showing a state of a TE signal obtained by a conventional optical information device.
- Beam splitter (diffraction grating) 70 ⁇ 73, 71a ⁇ 71h Beam
- FIG. 1 shows the configuration of the optical information device according to the present embodiment.
- the optical pickup head device 201 (also referred to as an optical pickup) irradiates the optical recording medium 40 with laser light having a wavelength ⁇ force of 05 nm, and reproduces a signal recorded on the optical recording medium 40.
- the transfer controller 205 moves the optical pickup head device 201 along the radial direction of the optical recording medium 40 in order to record or reproduce information at an arbitrary position on the optical recording medium 40.
- a motor 206 that drives the optical recording medium 40 rotates the optical recording medium 40.
- the controller 207 controls the optical pickup head device 201, the transfer controller 205, and the motor 206.
- the amplifier 208 amplifies the signal read by the optical pickup head device 201. An output signal from the amplifier 208 is input to the controller 209.
- the controller 209 Based on this signal, the controller 209 generates a servo signal, such as an FE signal or a TE signal, which is required when the optical pickup head device 201 reads the signal of the optical recording medium 40, and generates the servo signal. Output to 207.
- the signal input to the controller 209 is an analog signal, but the controller 209 digitalizes (binarizes) the analog signal.
- the demodulator 210 analyzes a signal that has been read and digitized from 40 optical recording media, reconstructs the original video and music data, and the reconstructed signal is output from the output device 214.
- the detector 211 detects an address signal or the like based on the signal output from the controller 209 and outputs it to the system controller 212.
- the system controller 212 identifies the optical recording medium 40 based on the physical format information read from the optical recording medium 40 and the optical recording medium manufacturing information (optical recording medium management information), decodes the recording / reproducing conditions, etc. This optical information device Control the whole.
- the controller 207 drives and controls the transfer controller 205 in accordance with an instruction from the system controller 212.
- the transfer controller 205 moves the optical pickup head device 201 to a desired position on the information recording surface formed on the optical recording medium 40 described later, and the optical pickup head device 201 Information is recorded on and reproduced from the information recording surface of the recording medium 40.
- FIG. 2 is a diagram showing an example of the configuration of the optical pickup head device 201 according to the present embodiment.
- the light source 1 emits a linearly polarized divergent beam 70 having a wavelength of 405 nm.
- the divergent beam 70 emitted from the light source 1 is converted into parallel light by a collimating lens 53 having a focal length fl of 18 mm, and then transmitted through the polarization beam splitter 52 and transmitted through the quarter-wave plate 54. Converted to circularly polarized light. Thereafter, it is converted into a convergent beam by an objective lens 56 having a focal length f2 of 2 mm, passes through a transparent substrate formed on the optical recording medium 40, and is condensed on the information recording surface 40a.
- the aperture of the objective lens 56 is limited by the aperture 55, and the numerical aperture NA is 0.85.
- the information recording surfaces 40a and 40b are formed on the optical recording medium 40.
- the surface force of the optical recording medium 40 is also 0.1 mm
- the thickness dl up to the information recording surface 40a, and the thickness d2 up to the information recording surface 40b is 75 ⁇ m.
- m and refractive index n are 1.57.
- the collimating lens 53 is moved in the optical axis direction by using a stepping motor or the like as the spherical aberration correcting means 93 for correcting the spherical aberration caused by the thickness difference between the information recording surface 40a and the black base material thicknesses dl and d2. It is configured to move freely.
- the beam 70 reflected by the information recording surface 40a passes through the objective lens 56 and the quarter-wave plate 54, is converted into linearly polarized light that is 90 degrees different from the forward path, and then is reflected by the polarizing beam splitter 52.
- the beam 70 reflected by the polarization beam splitter 52 is divided into a zero-order diffracted light beam 70 and first-order diffracted light beams 70a to 70d by a diffraction grating 60, which is a beam splitting element, and a focusing lens 59 having a focal length f3 of 30 mm.
- the light enters the photodetector 32 through the cylindrical lens 57.
- the beam 70 incident on the photodetector 32 is given astigmatism when passing through the cylindrical lens 57.
- FIG. 3 schematically shows the configuration of the diffraction grating 60
- FIG. 4 schematically shows the relationship between the photodetector 32, the beam 70 received by the photodetector 32, and the beams 70a to 70d.
- the diffraction grating 60 has a total of four types of regions 60a to 60d, which may be either a simple groove shape or a stepped or saw blade shape.
- First-order diffracted light diffracted in region 60a is 70a
- first-order diffracted light diffracted in region 60b is 70b
- first-order diffracted light diffracted in region 60b is 70b
- first-order diffracted light diffracted in region 60c is 70c
- region 60d The first-order diffracted light diffracted at is 70d.
- the regions 60a and 60b include many tracking groove components that are first-order diffracted light diffracted by the tracks on the information recording surface 40a
- the regions 60c and 60d include almost no tracking groove components. Divided and structured.
- the diameter of the beam 70 incident on the diffraction grating 60 after being reflected by the polarizing beam splitter 52 is usually designed to be about 2 to 4 mm.
- the FE signal is obtained by the astigmatism method using the signals I32a to I32d output from the photodetector 32, that is, (I32a + I32c) ⁇ (I32b + I32d).
- the TE signal is obtained by (I32e-I32f)- ⁇ (I32h-I32g), where K is a real number.
- FE signal and TE signal are amplified and phase-compensated to a desired level, and then supplied to the actuators 91 and 92 for moving the objective lens 56 for force and tracking control.
- the information recording surface 40b When the beam 70 is focused on the information recording surface 40a, the information recording surface 40b is largely defocused. Therefore, the 0th-order diffracted light transmitted through the diffraction grating 60 of the beam 71 reflected by the information recording surface 40b is largely defocused on the photodetector 32.
- the light receiving portions 32e to 32j are arranged so that the beam 71 is always incident on the light receiving portions 32e to 32h. This is because when the interlayer thickness between the information recording surfaces 40a and 40b changes, the TE signal is disturbed depending on whether the beam 71 is incident on the light receiving portions 32e to 32h, and as a result, stable tracking control can be performed. This is to prevent disappearance.
- the optical information device shown in this embodiment can reduce the fluctuation of the TE signal amplitude and perform a stable tracking operation, so that information can be recorded or reproduced with high reliability.
- the optical recording medium provided with the two-layer information recording surface has been described. However, the same effect can be obtained for an optical recording medium having more information recording surfaces. 5 to 7 show the relationship between the light reflected by the optical recording medium having four layers of information recording surfaces and the optical detector 32. FIG.
- the information recording surfaces 40a, 40b, 40c, 40d and the reflected beams from the information recording surfaces are 70, 71, 72, 73, respectively.
- each beam on the photodetector 32 is arranged so that the beam 71 is always incident on the photodetectors 32e to 32h as shown in FIG.
- the photodetectors 32e to 32h may be arranged at positions where the beam 71 is not incident and the beam 72 is always incident.
- the same effect can be obtained even if the beams 71 and 72 are not incident and the beam 73 is always incident.
- FIG. 8 is a diagram schematically showing the relationship between the photodetector 33 and the beam 70 received by the photodetector 33, the beam 71, and the beams 70a to 70d used in the present embodiment.
- the difference between the optical pickup of the present embodiment and the optical pickup of the first embodiment is that the photodetector 33 is used instead of the photodetector 32.
- the difference between the light detector 32 and the light detector 33 is that the light receiving portions 33i to 331 are abbreviated as light receiving portions 33e to 33h with respect to the center of the beam 71 reflected by the information recording surface 40b that is not focused. This means that it is placed at a target position.
- the TE signal using this photodetector 33 is obtained by (I33e—133 ⁇ 4)-(I 33f-I33i) — ⁇ ⁇ ((I33h-I33k)-(I33g— 1331)), where K is a real number. .
- the optical information apparatus of the present embodiment can reduce the fluctuation of the TE signal and perform the tracking operation stably, so that information can be recorded or reproduced with high reliability.
- FIG. 9 is a diagram schematically showing the relationship between the photodetector 34 used in the present embodiment, the beam 70 received by the photodetector 34, and the beams 70a to 70n.
- the difference between the optical pickup of the present embodiment and the optical pickup of the first embodiment is that a diffraction grating 61 (not shown) is used instead of the diffraction grating 60 and a photodetector 34 is used instead of the photodetector 32. is there.
- the cross-sectional shape of the diffraction grating 60 may be either a simple groove shape or a stepped or serrated blazed shape, but the diffraction grating 61 of the present embodiment is It has a simple groove cross-sectional shape that generates diffracted light. Further, in the same manner as the diffraction grating 60 of FIG. 3, it has four types of regions 6 la to 6 Id in total.
- the beam divided by the diffraction grating 61 will be described. Reflected by the information recording surface 40b and diffracted by the region 61a of the diffraction grating 61 + 70a for the 1st order diffracted light, 70e for the 1st order diffracted light, 70b for the 1st order diffracted light 70b for the 1st order diffracted light Is 70f, + 1st order diffracted light diffracted in region 61c is 70c, ⁇ 1st order diffracted light is 70g, + 1st order diffracted light diffracted in region 61d is 70d, and ⁇ 1st order diffracted light is 70h.
- the beams 70a to 70h are incident on the photodetector 34 as shown in FIG.
- the TE signal at this time is obtained by ((I34e + I34j) — (I34f + I34i)) ⁇ ⁇ ⁇ ((I34h + I3 4k) ⁇ (I34g + I341)).
- the optical information device described in this embodiment can reduce the fluctuation of the TE signal amplitude and perform a stable tracking operation, so that information can be recorded or reproduced with high reliability. .
- FIG. 10 is a diagram showing an example of the configuration of another optical pickup device 202 according to the present embodiment.
- a diffraction grating 62 is used instead of the diffraction grating 60 which is a beam splitting means, an aperture limiting element 80 which is an aperture limiting means in the vicinity of the diffraction grating 62, and a photodetector.
- the light detector 35 is provided instead of 32.
- the aperture limiting element 80 has a structure as shown in FIG. That is, the region corresponding to the tracking direction of the objective lens 56 has a long oval shape region, and the positional relationship in which the center of the oval shape and the center of the diffraction grating 62 substantially coincide is maintained. The beam passing through the outer region of the oval shape is shielded so as not to enter the photodetector 35.
- the difference between the diffraction grating 60 and the diffraction grating 62 of the first embodiment is that the direction of diffraction is rotated ⁇ around the 0th-order diffracted light (see FIG. 12). ⁇ is about 40 to 50 degrees, preferably 45 degrees.
- the optical recording medium 40 is focused, and the beam shape of the beam reflected from the information recording surface 40b on the photodetector 35 is changed. It is schematically represented by a circle.
- a reflected beam having an information recording surface strength is transmitted through the cylindrical lens 57, so that the reflected beam from the information recording surface which is not focused has an elliptical shape on the photodetector 35.
- the direction of the ellipse of the beam reflected by the information recording surface that is not focused on the photodetector 35 is determined by the direction of the curvature surface of the cylindrical lens 57.
- the light receiving portions 35e to 35h that receive the beams 70a to 70d divided by the diffraction grating 62 are used to track the 0th-order diffracted light transmitted through the diffraction grating 62 on the information recording surface 40a. It is arranged in a direction different from the diffraction direction. In this embodiment, it is arranged in a direction rotated about 40 degrees to 50 degrees with respect to the track turning direction, and has a positional relationship of receiving 70a to 70d divided by the diffraction grating 62.
- the TE signal in this optical pickup is obtained by (I35e—I35f) — ⁇ (I35h—I35g), as in the first embodiment.
- the mapping of the beam 71a reflected by the information recording surface 40a on the photodetector 35 is shown by the dotted line in FIG.
- the mapping on the photodetector 35 of 71b reflected by the information recording surface 40b is 71a and 90
- the shape is an ellipse that has been rotated by a predetermined degree, and the mapping shown by the dotted line in FIG.
- the optical information device can reduce the fluctuation of the TE signal amplitude and perform the tracking operation stably, the information can be recorded or reproduced with high reliability.
- the aperture limiting element 80 is configured differently from the diffraction grating 62, but the same effect can be obtained even if it is formed integrally with the diffraction grating. Further, the aperture may be limited by making the diffraction grating 62 into a holder shape.
- Embodiments 1 to 4 described above are merely examples, and can take various forms without departing from the spirit of the present invention. Examples are shown below.
- the diffraction gratings 60 to 62 are divided into four regions, but the number of regions to be divided is not limited to this. In other words, any structure may be used as long as it is divided into a region mainly containing the tracking groove component on the information recording surface and a region containing almost no tracking groove component.
- the TE signal is not used near the center of the beam. Can be obtained.
- optical system has been described as being polarized, but a non-polarized optical system may be used.
- the FE signal detection method other than the astigmatism method has not been described because it is not related to the gist of the present invention.
- the FE signal detection method such as the spot size detection method and the Foucault method. All FE signal detection methods can be used. Even if there is a variation in the position, width, and depth of the track during the production of the optical recording medium, or when using an optical recording medium in which the TE signal amplitude fluctuates due to the recording of information on the track, this embodiment is used. In all the optical information devices shown, fluctuations in TE signal amplitude can be reduced and stable tracking operation can be performed. Therefore, it is possible to improve the yield of the optical recording medium and provide an inexpensive optical recording medium.
- optical recording media with varying TE signal amplitude can be tolerated, laser beam can be used to cut the master of optical recording media at high speed, which is faster and cheaper than cutting the master using an electron beam.
- a master can be produced. For that reason, an inexpensive optical recording medium The body can be provided.
- the optical information apparatus can show the features described so far particularly remarkably.
- the optical information device according to the present invention can be applied to applications such as an optical information device that requires a fluctuation in TE signal amplitude to record or reproduce information with high reliability.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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US10/592,641 US20070189130A1 (en) | 2004-09-09 | 2005-08-24 | Optical information device and information recording and reproduction device |
JP2006535109A JPWO2006027955A1 (ja) | 2004-09-09 | 2005-08-24 | 光情報装置及び情報記録/再生装置 |
Applications Claiming Priority (2)
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JP2004261919 | 2004-09-09 | ||
JP2004-261919 | 2004-09-09 |
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WO2006027955A1 true WO2006027955A1 (ja) | 2006-03-16 |
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PCT/JP2005/015368 WO2006027955A1 (ja) | 2004-09-09 | 2005-08-24 | 光情報装置及び情報記録/再生装置 |
Country Status (4)
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US (1) | US20070189130A1 (ja) |
JP (1) | JPWO2006027955A1 (ja) |
CN (1) | CN1942941A (ja) |
WO (1) | WO2006027955A1 (ja) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7808878B2 (en) | 2007-09-27 | 2010-10-05 | Sharp Kabushiki Kaisha | Optical pickup apparatus and drive apparatus having the same |
US8045427B2 (en) * | 2006-04-18 | 2011-10-25 | Lg Electronics Inc. | Apparatus for optical pick-up |
JP2014238904A (ja) * | 2013-06-10 | 2014-12-18 | 三菱電機株式会社 | 光ヘッド装置、および多層光ディスク装置 |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007335047A (ja) * | 2006-06-19 | 2007-12-27 | Sony Corp | 光ディスク装置、およびピックアップ装置 |
JP2009129483A (ja) * | 2007-11-20 | 2009-06-11 | Sanyo Electric Co Ltd | 光ピックアップ装置 |
KR20090090506A (ko) * | 2008-02-21 | 2009-08-26 | 엘지전자 주식회사 | 데이터 기록/재생 방법 및 장치 |
JP5174913B2 (ja) * | 2008-08-11 | 2013-04-03 | 三菱電機株式会社 | 光ヘッド装置及び光ディスク装置 |
US8472300B2 (en) * | 2010-01-18 | 2013-06-25 | Mitsubishi Electric Corporation | Optical head device and optical disc device |
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JPH04119531A (ja) * | 1990-09-10 | 1992-04-21 | Mitsubishi Electric Corp | 光ピックアップ装置 |
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JPH035927A (ja) * | 1989-06-01 | 1991-01-11 | Sony Corp | 光学記録および/または再生装置 |
-
2005
- 2005-08-24 WO PCT/JP2005/015368 patent/WO2006027955A1/ja active Application Filing
- 2005-08-24 US US10/592,641 patent/US20070189130A1/en not_active Abandoned
- 2005-08-24 JP JP2006535109A patent/JPWO2006027955A1/ja active Pending
- 2005-08-24 CN CNA2005800113136A patent/CN1942941A/zh active Pending
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JPH04119531A (ja) * | 1990-09-10 | 1992-04-21 | Mitsubishi Electric Corp | 光ピックアップ装置 |
JP2001273640A (ja) * | 2000-03-28 | 2001-10-05 | Hitachi Ltd | 光情報記録再生装置 |
JP2002319177A (ja) * | 2001-04-24 | 2002-10-31 | Hitachi Ltd | 光ヘッドおよび光ディスク装置 |
JP2003067949A (ja) * | 2001-06-04 | 2003-03-07 | Matsushita Electric Ind Co Ltd | 光ピックアップヘッドおよび情報記録再生装置 |
JP2003016672A (ja) * | 2001-06-27 | 2003-01-17 | Toshiba Corp | 光ヘッド装置及び光ヘッド制御装置 |
WO2004068480A1 (ja) * | 2003-01-30 | 2004-08-12 | Matsushita Electric Industrial Co., Ltd. | 光ヘッドとこれを備えた装置及びシステム |
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Publication number | Priority date | Publication date | Assignee | Title |
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US8045427B2 (en) * | 2006-04-18 | 2011-10-25 | Lg Electronics Inc. | Apparatus for optical pick-up |
US7808878B2 (en) | 2007-09-27 | 2010-10-05 | Sharp Kabushiki Kaisha | Optical pickup apparatus and drive apparatus having the same |
CN101399061B (zh) * | 2007-09-27 | 2011-03-23 | 夏普株式会社 | 光学拾取头装置及具有该光学拾取头装置的驱动器装置 |
CN102034499B (zh) * | 2007-09-27 | 2012-12-19 | 夏普株式会社 | 光学拾取头装置及具有该光学拾取头装置的驱动器装置 |
JP2014238904A (ja) * | 2013-06-10 | 2014-12-18 | 三菱電機株式会社 | 光ヘッド装置、および多層光ディスク装置 |
Also Published As
Publication number | Publication date |
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US20070189130A1 (en) | 2007-08-16 |
JPWO2006027955A1 (ja) | 2008-05-08 |
CN1942941A (zh) | 2007-04-04 |
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