WO2007116631A1 - 光ディスク装置 - Google Patents
光ディスク装置 Download PDFInfo
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- WO2007116631A1 WO2007116631A1 PCT/JP2007/055523 JP2007055523W WO2007116631A1 WO 2007116631 A1 WO2007116631 A1 WO 2007116631A1 JP 2007055523 W JP2007055523 W JP 2007055523W WO 2007116631 A1 WO2007116631 A1 WO 2007116631A1
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- WIPO (PCT)
- Prior art keywords
- light
- optical disc
- detection
- diffracted
- objective lens
- Prior art date
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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
- G11B7/08—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
- G11B7/0903—Multi-beam tracking systems
-
- 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
- G11B7/094—Methods and circuits for servo offset compensation
-
- 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
Definitions
- the present invention relates to an optical disk device used for recording a signal on an optical disk or reproducing a signal recorded on an optical disk.
- FIG. 8 (a) is a side view showing an optical disc device according to the prior art
- Fig. 8 (b) is a grating pattern formed on a grating surface used in the optical disc device, and on the grating surface
- FIG. 8 (c) is a diagram showing the configuration of the signal surface of the optical disc and the state of the light distribution on the signal surface.
- the laser light 2 emitted from the radiation source 1 such as a semiconductor laser is sequentially transmitted through the transparent substrate 3 and the split surface 4a of the polarization beam splitter 4, and then collected by the collimating lens 5. It becomes light and becomes parallel light.
- This parallel light is converted from linearly polarized light (P wave) to circularly polarized light by the 1Z4 wavelength plate 6, then condensed by the objective lens 7, and focused on the signal surface 8 a of the optical disk 8 (connecting the light spot).
- optical disk rotation direction On the signal surface 8a of the optical disk 8, guide grooves 8g along the rotation direction of the optical disk 8 (hereinafter referred to as “optical disk rotation direction”) are formed at equal pitches in the radial direction of the optical disk 8 (hereinafter referred to as “optical disk radial direction”).
- optical disk radial direction has been.
- the light reflected by the signal surface 8 a of the optical disk 8 passes through the objective lens 7, is converted into linearly polarized light (S wave) by the 1Z4 wavelength plate 6, and becomes convergent light via the collimator lens 5.
- This convergent light is reflected by the split surface 4a of the polarization beam splitter 4 and then passes through the cylindrical lens 9 arranged with the central axis of the cylindrical surface inclined by 45 degrees with respect to the plane parallel to the paper surface.
- the light is incident on the light detection surface 10a on the light detection substrate 10 located in the vicinity of the circle (an intermediate position between the vertical focal line and the horizontal focal line).
- the surface of the transparent substrate 3 (grating surface 3a) has an axis 3 corresponding to the optical disk rotation direction.
- a straight grating 3b and a straight grating 3c are formed with Y as a boundary.
- the shape of the light spot on the grating surface 3a of the light (transmitted light) emitted from the radiation source 1 and transmitted through the transparent substrate 3 is a circle 2a centering on the center 30 of the grating surface 3a.
- the orientation of each grating is orthogonal to the axis 3Y, and the phase of the gratings of the linear grating 3b and the linear grating 3c is shifted by ⁇ !
- Gr diffracted light Light that passes through the transparent substrate 3 (transmitted light) is diffracted by the linear grating 3b and the linear grating 3c, and ⁇ 1st-order diffracted light is generated in addition to the 0th-order diffracted light (light that is transmitted as it is) (hereinafter, diffraction by the grating).
- Light is called “Gr diffracted light”).
- the wavefront of the 0th-order Gr diffracted light is not affected by the grating, so there is no phase change, but the wavefront of the ⁇ 1st-order Gr diffracted light is shifted by ⁇ on the left and right with the axis 3Y as a boundary.
- These Gr diffracted lights form a light spot on the signal surface 8 a of the optical disk 8.
- the light spot 2b corresponding to the 0th-order Gr diffracted light is positioned directly above the guide groove 8g, and the light spots 2b 'and 2b "corresponding to the first-order Gr diffracted light are respectively guided grooves.
- the two light spots are separated in the optical disk radial direction centered on 8g.
- the wavefront of the first-order Gr diffracted light is on the left and right sides of the central axis 3Y. This is because the phase is shifted by ⁇ .
- the diffraction efficiencies of the linear grating 3b and the linear grating 3c are set so that the light amounts of the light spots 2b and 2b "are about 1Z10 of the light amount of the light spot 2b.
- FIG. 9 (a) is a diagram showing the configuration of the light detection surface used in the optical disk device in the prior art and the state of light distribution on the light detection surface
- FIG. It is a figure which shows the light beam before injecting into the used cylindrical lens.
- the light beams 2c, 2c ′, and 2c ′′ before entering the cylindrical lens 9 correspond to the light spots 2b, 2b ′, and 2b ′′ on the signal surface 8a of the optical disc 8, respectively.
- the 0th-order Gr diffracted light 2c is superposed with diffracted lights 2cp and 2cm from the guide groove 8g of the optical disk 8 in a form shifted along the axis 9X corresponding to the radial direction of the optical disk (hereinafter referred to as the guide groove).
- Diffraction light is called “groove diffraction light”).
- ⁇ 0th order Gr diffracted light 2c ', 2c 0th order groove diffracted light is phase shifted by ⁇ from axis 9Y parallel to the optical disc rotation direction.
- the light spot 2d on the photodetection surface 10a is superimposed on the 0th-order groove diffracted light while shifting along the axis 9mm.
- 2d, and 2d "correspond to the luminous fluxes 2c, 2c, and 2c" before entering the cylindrical lens 9, respectively.
- the light beams 2c, 2c ', 2c are transmitted through the cylindrical lens 9 and the light distribution is inverted with respect to the central axis of the cylindrical surface of the cylindrical lens 9, so that the light spots 2d, 2d on the light detection surface 10a ', 2d, and are the light distribution rotated 90 degrees as a whole with respect to the luminous fluxes 2c, 2c', 2c, and so on (not only the light distribution but also the lens shift of the objective lens 7 (hereinafter referred to as the objective lens lens shift) (It is also simply called “lens shift”).
- the light detectors 11, 11 'and 11 "force S are arranged so as to be substantially coaxial with the light spots 2d, 2d' and 2d", respectively.
- Tl signal obtained in the detection cell 11a
- T2 Signal obtained at detection cell l ib
- T4 Signal obtained from detection cell l id
- T2 ' signal obtained at detection cell l ib'
- T4 ' signal obtained at detection cell l id'
- the tracking error signal TE to the optical disc track the tracking error signal TE to the optical disc track, the focus error signal FE to the optical disc signal surface, and the reproduction signal RF to the optical disc signal surface are calculated by the following formulas (1) to (3). Is done. [0009] TE T1 + T2-T3-T4
- the coefficient k is set to a magnitude that cancels the offset of the tracking error signal generated by the lens shift at the time of tracking control. For example, light spot
- the coefficient k is about 5.
- FIG. 10 is a diagram for explaining the offset of the tracking error signal generated by the lens shift in the optical disc apparatus according to the prior art (by the cylindrical lens).
- the light spot 2d on the photodetector 11 is also proportional to 2 ⁇ (strictly speaking, 2 ⁇ (half the astigmatic difference of the cylindrical lens 9) / (focal length of the collimating lens 5)
- a circle 7a (proportional to ⁇ ), which is a light distribution centered on 2D and shifted along the ray on the light detection surface 10a of the aperture of the objective lens 7. The outside of the shift) is shielded from light.
- Polarity is reversed between the tracking error signal and the tracking error signal obtained only by the photodetector 11 ', 11 ". This is because the phase of the groove diffracted light of the light spot on the photodetector 11', 11" is the optical disc. Shift by ⁇ from the axis parallel to the direction of rotation! This is because the interference relationship between the groove diffracted light is reversed. Therefore, the tracking error signal obtained by the above equation (1) does not impair the detection sensitivity (rather than increase the detection output) compared to the tracking error signal (T1 + T2 ⁇ T3 ⁇ ⁇ 4) obtained by the photodetector 11 alone. However, the effects of off-track due to lens shift can be canceled.
- Patent Document 1 JP-A-9 81942
- the conventional optical disc apparatus as described above has the following problems. That is, in FIG. 8, when the positions of the light spots 2b, 2b "are shifted and the centers of the two light spots of the light spots 2b, 2b" are located in the vicinity of the intermediate portion 81 of the guide groove 8g, The polarity of the tracking error signal obtained only with the photodetector 11 ', 11 "is the same as the polarity of the tracking error signal obtained only with the photodetector 11. And the positions of the light spots 2b', 2b" are changed.
- the tracking error offset generated by the lens shift does not change, so if the coefficient k is determined so as to cancel the off-track effect due to the lens shift, the tracking error signal obtained by the above equation (1) can be obtained.
- the detection output of this becomes small, and the detection output may become zero. Therefore, in the conventional optical disc apparatus as described above, the linear gratings 3b and 3c are formed so that the two light spots of the light spots 2b and 2b "are symmetrical about the guide groove 8g. It is necessary to accurately rotate and adjust the transparent substrate 3, which makes it difficult to assemble the optical disk apparatus.
- the present invention has been made to solve the above-described problems in the prior art, and without off-tracking the tracking error signal without impairing the detection output of the tracking error signal without adjusting the rotation of the linear grating.
- An object of the present invention is to provide an optical disc apparatus capable of canceling the influence.
- the configuration of the optical disc apparatus includes a radiation light source, a circuit A diffraction grating formed on the folded grating surface, an objective lens, a light branching means, and a photodetector are provided, and the light emitted from the radiation light source passes through the diffraction grating and transmits transmitted light a.
- + 1st-order diffracted light b and 1st-order diffracted light c, and the transmitted light a, the + 1st-order diffracted light b, and the 1st-order diffracted light c pass through the objective lens with their parts overlapping.
- the light condensed on the track on the signal surface of the optical disk and reflected by the track on the signal surface enters the light branching means via the objective lens, and the light incident on the light branching means Depending on the incident position, the light corresponding to the transmitted light a splits into two light a 1 and a 2 and enters the light detection areas Al and A 2 on the photodetector, respectively, and + 1
- the light corresponding to the next diffracted light b splits into light bl and b2, and enters the light detection areas Bl and B2 on the photodetector, respectively.
- the light corresponding to the first-order diffracted light c splits into two light beams cl and c2, and enters the light detection regions Cl and C2 on the photodetector, respectively, and the light detection regions Al, A2, Bl, B2,
- a tracking error signal to the track of the optical disk is generated by combining detection signals from CI and C2.
- the objective lens and the light branching unit are fixed in a body-like manner.
- the light detection region A2 is electrically connected to the light detection region A1 in a state where the constant k is applied to the light detection region A1, and the light detection region It is preferable that the photodetection region C1 is electrically connected to A2 with a coefficient k.
- the light detection area A1 and the light detection area C2 are electrically connected or are the same light detection area, and the light detection area It is preferable that A2 and the light detection region B1 are electrically connected or are the same light detection region.
- the tracking error to the track of the optical disc The signal is preferably computed by ⁇ 1 -k X ⁇ 4 using the coefficient k.
- the projection area on the light branching unit corresponding to the + first-order diffracted light b does not exceed the radius of the objective lens! / Has a heel width,
- the region of the diffraction grating on the diffraction grating surface is the projection figure of the opening. It is preferable that the width does not exceed the radius and passes along the straight line corresponding to the rotation direction of the optical disc through the center of the projected figure of the opening.
- the diffraction grating is preferably a linear grating along the radial direction of the optical disk.
- the region of the diffraction grating is located outside the projection pattern of the opening.
- the diffraction grating is further divided into a plurality of strip-shaped regions along a straight line corresponding to the rotation direction of the optical disc, and the irregularities of the diffraction grating are synchronized in every other strip-shaped region. It is preferable that the concave and convex portions of the diffraction grating are shifted by a pitch of 1Z5 to 1Z2! /
- the optical branching unit is divided into two regions by a straight line passing through the center of the objective lens and parallel to the optical disc rotation direction. It is preferable that the light al and the light a2, the light bl and the light b2, and the light cl and the light c2 are branched, respectively.
- the difference between the detection signals in the light detection areas Al and A2 is ⁇ 1
- the difference between the detection signals in the light detection areas Bl and ⁇ 2 is ⁇ ⁇ ⁇ 2
- an optical disc apparatus capable of canceling the off-track effect accompanying the lens shift without impairing the detection output of the tracking error signal without adjusting the rotation of the linear grating. Can do.
- FIG. 1 (a) is a side view showing an optical disc apparatus according to an embodiment of the present invention
- FIG. 1 (b) is a plan view showing a light source portion of the optical disc apparatus
- FIG. ) Indicates the grating pattern formed on the grating surface used in the optical disc apparatus, and the grating.
- Fig. 1 (d) shows the configuration of the signal surface of the optical disc and the state of the light distribution on the signal surface.
- Fig. 1 (f) is a diagram showing the state of light distribution when the pitch of the grating pattern is large on the hologram surface used in the optical disc device.
- Fig. 1 (f) shows the dulling on the hologram surface used in the optical disc device. It is a figure which shows the mode of light distribution in case the pitch of a pattern is small.
- FIG. 2 (a) shows a photodetection pattern formed on the photodetector used in the optical disc apparatus according to the first embodiment of the present invention, and the return light to the laser beam emitted from the radiation light source.
- FIG. 2B is a diagram showing a state of light distribution on the photodetector, and
- FIG. 2B is a diagram showing a configuration of a hologram used in the optical disc apparatus.
- FIG. 3 is a diagram showing a state of light distribution on the light detection surface when the concentrated light is defocused with respect to the signal surface of the optical disc in the first embodiment of the present invention.
- (A) is the case where the signal surface of the optical disk is on the side away from the objective lens
- (b) is the case where the signal surface of the optical disk is on the side approaching the objective lens.
- Fig. 4 is a diagram showing the light distribution on the hologram surface of the return light from the optical disc in the optical disc apparatus according to the first embodiment of the present invention.
- (b) is for ⁇ 1st order Gr diffracted light.
- FIG. 5 is a diagram for explaining an offset of a tracking error signal generated due to a lens shift of the objective lens in the optical disc device according to the first embodiment of the present invention.
- Gr diffracted light distribution on the hologram surface (b) ⁇ 1st order Gr diffraction light distribution on the hologram surface, (c) Groove diffracted light distribution on the hologram surface Show each of them!
- FIG. 6 shows a photodetection pattern formed in a photodetector used in the optical disc apparatus according to the second embodiment of the present invention, and a return light with respect to a laser beam emitted from a radiation light source.
- FIG. 6B is a diagram showing a state of light distribution on the photodetector, and
- FIG. 6B is a diagram showing a configuration of a hologram used in the optical disc apparatus.
- FIG. 7 is a diagram showing a state of light distribution on the light detection surface when the condensed light is defocused with respect to the signal surface of the optical disc in the second embodiment of the present invention.
- (A) is when the signal surface of the optical disc is closer to the objective lens
- (b) is the signal of the optical disc This is the case where the surface is on the side away from the objective lens.
- FIG. 8 (a) is a side view showing an optical disc device in the prior art
- FIG. 8 (b) is a diagram showing a grating pattern formed on a grating surface used in the optical disc device.
- FIG. 8 (c) is a diagram showing the configuration of the signal surface of the optical disc and the state of the light distribution on the signal surface.
- FIG. 9 (a) is a diagram showing a configuration of a light detection surface used in an optical disc apparatus in the prior art and a state of light distribution on the light detection surface
- FIG. 9 (b) It is a figure which shows the light beam before injecting into the cylindrical lens used for an optical disk apparatus.
- FIG. 10 is a diagram for explaining an offset of a tracking error signal generated by a lens shift in an optical disc apparatus according to a conventional technique.
- FIG. 1 (a) is a side view showing an optical disc apparatus according to an embodiment of the present invention
- FIG. 1 (b) is a plan view showing a light source portion of the optical disc apparatus
- FIG. Fig. 1 (d) shows the grating pattern formed on the grating surface used and the state of light distribution on the grating surface.
- Fig. 1 (d) shows the configuration of the signal surface of the optical disc and the light on the signal surface.
- Fig. 1 (e) is a diagram showing the state of the distribution
- Fig. 1 (e) is a diagram showing the state of the light distribution when the pitch of the grating pattern is large on the hologram surface used in the optical disc device. It is a figure which shows the mode of the light distribution in case the pitch of a darting pattern is small on the hologram surface used for the said optical disk apparatus.
- the optical disc apparatus includes a radiation light source 1 such as a semiconductor laser, a diffraction grating that diffracts light emitted from the radiation light source 1, and a diffraction A collimating lens 5 that converts light diffracted by the grating into parallel light, a 1Z4 wavelength plate 6 that converts linearly polarized light into circularly polarized light and circularly polarized light into linearly polarized light, and the parallel light into the optical disc 8 signal surface 8a.
- a radiation light source 1 such as a semiconductor laser
- a diffraction grating that diffracts light emitted from the radiation light source 1
- a diffraction A collimating lens 5 that converts light diffracted by the grating into parallel light
- a 1Z4 wavelength plate 6 that converts linearly polarized light into circularly polarized light and circularly polarized light into linearly polarized light
- the parallel light into the optical disc 8 signal surface 8a.
- the photodetector includes a light detection substrate 10 and a light detection surface 10a formed on the light detection substrate 10.
- the light detection surface 10a is substantially located at the focal plane position of the collimating lens 5 (that is, the virtual light emission point position of the light emission point la of the radiation source 1 shown in FIG. 1B).
- the radiation source 1 is mounted on the light detection substrate 10. Further, on the light detection substrate 10, a reflection mirror 12 is mounted in the vicinity of the radiation light source 1 to reflect the laser light emitted from the radiation light source 1 and bend its optical path.
- the diffraction grating includes a transparent substrate 3, and linear gratings 3b and 3c formed on the surface of the transparent substrate 3 (grading surface 3a).
- the straight grating 3b and the straight grating 3c are formed separately along the axis 3Y passing through the center 30 of the grating surface 3a. More specifically, if the figure projected on the grating surface 3a along the incident light beam (outward ray) of the aperture of the objective lens 7 is a circle 2a, the regions of the straight gratings 3b and 3c are outside the circle 2a. Is located.
- Each grating has an equal pitch and its orientation is perpendicular to axis 3Y (ie, parallel to axis 3X perpendicular to axis 3Y).
- the linear gratings 3b and 3c are each divided into two regions along the axis 3Y at intervals of 20 m (or 20 ⁇ m to 40 ⁇ m), and the phase of the grating is 1Z4 pitch between the two regions. (Ie, shifted by ⁇ / 2) (the phase shift is preferably about 1 ⁇ ⁇ ⁇ ⁇ 5 to 1 ⁇ 2 pitch).
- the width of the straight grating 3b and the straight grating 3c in the direction of the axis 3X is about 1Z3 of the diameter of the circle 2a (at least not more than half the diameter of the circle 2a).
- the straight grating 3b and the straight grating 3c have a blazed shape (sawtooth shape) or a step shape inscribed in a sawtooth shape along the axis 3Y, and the diffraction efficiency thereof is the light spot 2b ', 2b "
- the light intensity of each is set to be about 1Z10 of the light intensity of the light spot 2b.
- the grating area is limited. In order to compensate for the small amount of diffracted light, a cross section with a high diffraction efficiency such as a blaze shape is adopted.
- the hologram is composed of a polarizing hologram substrate 13 and a hologram surface 13a formed on the polarizing hologram substrate 13 as a light branching means. And with Yes.
- the 1Z4 wavelength plate 6 is provided on the polarization hologram substrate 13 on which the hologram surface 13a is formed (the 1Z4 wavelength plate 6 is bonded to the polarization hologram substrate 13). And is configured to move together with the objective lens 7.
- the laser light 2 emitted from the light emitting point la of the radiation light source 1 is reflected by the reflection mirror 12, passes through the transparent substrate 3, and then is collected by the collimator lens 5 to be parallel. It becomes light.
- the parallel light passes through the polarizing hologram substrate 13, is converted from linearly polarized light (S wave or P wave) to circularly polarized light by the 1Z4 wavelength plate 6, is then condensed by the objective lens 7, and Focus on the signal surface 8a (connect the light spot).
- the shape of the light spot of the light (transmitted light) emitted from the radiation source 1 and transmitted through the transparent substrate 3 on the grating surface 3a is a circle 2a centered on the center 30 of the grating surface 3a.
- the light distribution of the laser beam 2 transmitted through the transparent substrate 3 on the grating surface 3a also spreads outside the circle 2a, and this spread component passes through the linear grating 3b and the linear grating 3c.
- the first-order diffracted light is generated (hereinafter referred to as “Gr diffracted light”).
- the light that can enter the aperture of the objective lens 7 is a component diffracted to the optical axis side (linear grating 3b—first-order Gr diffracted light, linear grating 3c + first-order Gr diffracted light), and these components are combined on the signal surface 8a of the optical disc 8 together with the component that passes through the inside of the circle 2a (not diffracted, but for convenience, called “0th order Gr diffracted light”). Tie a light spot to
- the light reflected by the signal surface 8a of the optical disc 8 passes through the objective lens 7, is converted into linearly polarized light (P wave or S wave) by the quarter wave plate 6, and then enters the hologram surface 13a.
- the linearly polarized light incident on the hologram surface 13a is diffracted by the hologram surface 13a and branched into a + first-order diffracted light 2 ′ and a first-order diffracted light 2 ′′ having the optical axis L as the symmetry axis (hereinafter referred to as a hologram).
- the diffracted light by is called "holo diffracted light".
- Each holo-diffracted light becomes convergent light via the collimating lens 5 and enters the light detection surface 10a on the light detection substrate 10.
- the light spot 2b corresponding to the 0th-order Gr diffracted light is located immediately above the guide groove 8g, but the light spots 2b, 2b "corresponding to ⁇ 1st-order Gr diffracted light (respectively, + 1st order Gr diffracted light with linear grating 3c, 1st order Gr diffracted light with linear grating 3b ) Does not have to be located directly above the guide groove 8g.
- the wavefront of ⁇ 1st-order Gr diffracted light is divided into two regions at intervals of 20 m along the axis 3Y, and the phase is shifted by ⁇ ⁇ 2 between the two regions.
- the light becomes three light spots separated in the direction of the guide groove 8g (optical disk rotation direction) (when the phase is shifted by ⁇ between the two regions, it becomes two light spots).
- the light reflected by the signal surface 8a of the optical disk 8 and passing through the objective lens 7 and entering the hologram surface 13a is obtained by superimposing ⁇ 1st order Gr diffracted light 2e, 2e "on 0th order Gr diffracted light 2e.
- FIG. 2 (a) shows a light detection pattern formed on the light detector used in the optical disk device according to the first embodiment of the present invention, and a return light with respect to the laser light emitted from the radiation light source force.
- FIG. 2B is a diagram showing a state of light distribution on the photodetector
- FIG. 2B is a diagram showing a configuration of a hologram used in the optical disc apparatus.
- FIGS. 2 (a) and 2 (b) show the light detection surface and the hologram surface viewed from the optical disk side.
- the first-order Gr diffracted beams 2e ′ and 2e ′′ on the hologram surface 13a are in the state shown in FIG.
- the hologram surface 13a has two straight lines (13X, 13Y) orthogonal to each other at the intersection 130 between the optical axis L and the hologram surface 13a. 134 [This harm has been ij.
- the axis 13X is parallel to the radial direction of the optical disc, and the return light (0th order Gr diffracted light 2e) on the hologram surface 13a is shifted along the axis 13X corresponding to the optical disc radial direction so that the signal of the optical disc 8
- the diffracted lights 2ep and 2em from the guide groove 8g formed on the surface 8a are superimposed (hereinafter, the diffracted light from the guide groove is referred to as “groove diffracted light”).
- the outline of the groove diffracted light is shown by a broken line, taking as an example the return light from a narrow pitch format optical disk such as DVD-R or DVD-RW.
- This light passes through the hologram surface 13a to generate ⁇ 1st-order diffracted light, which is divided into quadrants 131, 132, 133, and 134.
- the light is incident on the light detection surface 10a on the light detection substrate 10.
- the light detection surface 10a has two straight lines orthogonal to the intersection point 100 of the optical axis L and the light detection surface 10a and parallel to the axis 13X and the axis 13Y.
- comb-like focus detection cells 95 and 96 along axis 10X are alternately arranged on the negative side of axis 10X (detection cells with the same reference numerals are electrically connected).
- the rectangular tracking detection cells 91, 92, 92, 93, 94, 94 are arranged on the positive side of the axis 10X (light detection pattern).
- These tracking detection cells 91, 92, 92, 93, 94, 94 have a 180 ° rotationally symmetric shape around the center of the boundary line of the tracking detection cells 92, 94.
- 92, 94, 94 are aligned in the direction of the axis 10Y, and the tracking detection cells 91, 93 are shifted from each other in the direction of the axis 10Y in the opposite directions along the axis 10X.
- the laser beam 2 emitted from the emission point la of the radiation source 1 travels in a plane parallel to the paper surface in parallel with the axis 10Y, and is reflected by the reflecting mirror 12 in the direction of the optical axis L (through the point 100 and directly to the paper surface). To reflect).
- the + 1st order holo diffracted light diffracted by the quadrant 131 of the hologram surface 13a becomes 1
- the first-order holo diffracted light is diffracted by the quadrant 132 of the hologram surface 13a into the light spot 2D1 straddling the boundary between the focus detection cells 95 and 96, and the first-order holo diffracted light is within the tracking detection cell 92.
- the first-order holo diffracted light is diffracted by the quadrant 133 of the hologram surface 13a into the light spot 2D2 straddling the boundary between the focus detection cells 95 and 96.
- the first-order holo-diffracted light is diffracted by the quadrant 134 of the hologram surface 13a into the light spot 2D3 straddling the boundary between the focus detection cells 95 and 96.
- the light spot 2d4 fits inside the in g detection cell 94, -1 order holo diffracted light, respectively collecting light into a light spot 2D4 across the boundaries of the focus detection cells 95, 96.
- the holo-diffracted light diffracted by the quadrant 131 of the hologram surface 13a is transmitted to the light spot 2dl 'outside the detection cell.
- the holo-diffracted light diffracted by the quadrant 132 of the surface 13a is condensed on the light spot 2d2 ′ that is contained inside the tracking detection cell 92 ′.
- the holo diffracted light diffracted by the quadrant 133 of the hologram surface 13a is the holo diffracted light diffracted by the light spot 2d3,. Condenses on each of the light spots 2d4 "that fall within the tracking detection cell 94 '.
- each quadrant 131, 132, 133, 134 of the hologram surface 13a The light spots 2D1, 2D2, 2D3 and 2D4 are approximately point-symmetrical positions with respect to the point 100 of the light spots 2dl, 2d2, 2d3, and 2d4, which are + first-order holo-diffracted light forces S, respectively.
- the 1st order Gr diffracted light 2e, 2e "holo diffracted light is based on the condensing position of the 0th order Gr diffracted light 2e holo diffracted light + 1st order Gr diffracted light 2e
- the holo diffracted light of ' is focused on the brass side of the axis 10Y
- the holo diffracted light of the first-order Gr diffracted light 2e is focused on the position shifted to the negative side of the axis 10Y.
- the focal line in the direction of the axis 10X of the light spots 2D1, 2D2, 2D3, and 2D4 is on either side of the light detection surface 10a (back (side away from the hologram surface 13a) or near (hologram surface 13a).
- the focal spot in the direction of the axis 10Y of the light spots 2D1 and 2D3 is located behind (or in front of) the light detection surface 10a and the direction of the axis 10Y of the light spots 2D2 and 2D4.
- the focal line is located in front of (or behind) the light detection surface 10a.
- each quadrant 131, 132, 133, 134 of the hologram surface 13a is divided into strip-shaped regions along the axis 13Y, and the holo-diffracted light diffracted by every other strip-shaped region is detected.
- a method of condensing holo diffracted light diffracted by the remaining strip-shaped region in the back of the surface 10a before the light detection surface 10a is also conceivable.
- Tl signal obtained in the detection cell 91
- F1 signal obtained at detection cell 95
- F2 Signal obtained at detection cell 96
- the tracking error signal TE 1 to the track of the recordable optical disc the tracking error signal T E2 to the track of the read-only optical disc such as DVD ROM
- the focus error signal FE to the signal surface of the optical disc the optical disc
- the reproduction signal RF of the signal plane is calculated by the following equations (4) to (7).
- the coefficient k is set to a size that cancels the influence of off-track accompanying the lens shift of the objective lens 7 (hereinafter, the lens shift of the objective lens is also simply referred to as “lens shift”) during tracking control.
- FIG. 3 is a diagram showing a state of light distribution on the light detection surface when the focused light is defocused with respect to the signal surface of the optical disc in the first embodiment of the present invention. a) is when the optical disc signal surface is on the side away from the objective lens, and (b) is when the optical disc signal surface is on the side closer to the objective lens. Note that in FIG. 3, only the light spot on the + first-order holo-diffracted light side is shown. The light spot on the first-order holo-diffracted light side relates to the point 100 of the light spot on the + first-order holo-diffracted light side. The position is almost point-symmetric. Fig.
- the light distribution 2dl, 2d3i and the detection senor 92, 92, 94, 94 can be hung! Until this time, the light distribution 2dl, 2d3 base / ⁇ , 2dlS, 2d3S force S is located above the detection cells 91, 93 which are offset in the opposite direction along the axis 10X. Due to that.
- Two-layer discs (DVD-R and Blu-ray discs, etc.) have two signal surfaces with an adhesive layer (thickness d, refractive index n) with a thickness of several tens of ⁇ m.
- an adhesive layer thinness d, refractive index n
- the light reflected by the other signal surface is detected in a state where it is defocused by dZn on the forward path and the return path, and 2dZn on the return path, respectively. Come back on the plane.
- the light reflected by the other signal surface may be mixed as stray light, which will greatly affect the tracking error signal and the focus error signal.
- the above formula (4) is used. Since only the detection cells 92, 92, 94, 94 'are used for tracking error detection, half of the light spot (2dl, 2d3) is not stray light in tracking error detection, and the remaining light spot ( Since 2d2 and 2d4) also cover the tracking detection cell while maintaining the symmetrical relationship, disturbance to the tracking error signal TE1 is cancelled. As a result, the tracking control in the two-layer disk can be stabilized, and the offtrack can be eliminated during tracking control.
- FIG. 4 is a diagram showing the state of light distribution on the hologram surface of the return light from the optical disc in the optical disc apparatus according to the first embodiment of the present invention, and (a) shows the 0th-order Gr diffracted light.
- Case (b) is the case of ⁇ 1st order Gr diffracted light (in fact, these Gr diffracted light overlap and return).
- the light beam (0th-order Gr diffracted light 2e) before entering the hologram surface 13a is shifted along the axis 13X corresponding to the optical disk radial direction, and the signal of the optical disk 8 is shifted. Diffracted beams 2ep and 2em from the guide groove 8g formed on the surface 8a are superimposed.
- the shift amount is given by ⁇ ⁇ ⁇ ⁇ , where f is the focal length of the objective lens 7, the wavelength of the light is ⁇ , and the pitch of the guide groove 8 g in the radial direction of the optical disk is ⁇ .
- the return light on the hologram surface 13a is cut outside the aperture of the objective lens 7, so that only the inside of the circle 7a, which is a figure in which the aperture of the objective lens 7 is projected along the light beam onto the hologram surface 13a, is cut.
- the 0th-order Gr diffracted light 2e has a region (superimposed region) overlapping with the ⁇ first-order groove diffracted light 2ep and 2em.
- the hologram surface 13a has ⁇ first-order Gr diffracted lights 2e, 2e "and their + first-order groove diffracted lights 2ep ', 2ep", and first-order groove diffracted lights 2em', 2em ".
- ⁇ 1st-order groove diffracted light 2ep, 2ep ", 2em, 2em” is shifted by ⁇ ⁇ ⁇ ⁇ along axis 13X with respect to 0th-order groove diffracted light.
- 1st order 01 diffracted light 26, 2e "and their + 1st-order groove diffracted light 2ep, 2ep", 1st-order groove diffracted light 2em, 2em "has a width in the direction of axis 13X, w If the size of is set to about 1Z3 of the radius (aperture radius) a of the circle 7a, it will not exceed 1Z2 of w force Sf ZA in any format optical disc. Therefore, the ⁇ 1st order Gr diffracted beams 2e, 2e "do not overlap the ⁇ 1st order groove diffracted beams 2ep, 2ep", 2em, 2em ", and the light spots 2b ', 2b" are guided grooves.
- phase information of groove diffracted light changes from 8g off-track However, this does not act as a tracking error signal.
- the light spots 2b 'and 2b "on the signal surface 8a do not need to be adjusted with respect to the guide groove 8g as in the prior art, regardless of the position of the guide groove 8g. It is not necessary to adjust the rotation of the linear gratings 3b and 3c.
- FIG. 5 is a diagram for explaining the offset of the tracking error signal generated by the lens shift of the objective lens in the optical disc apparatus according to the first embodiment of the present invention.
- the objective lens 7 when the objective lens 7 is shifted by ⁇ in the optical axis L force optical disk radial direction (direction of the axis 13X), the objective lens 7 enters the objective lens 7 along the optical axis L in a rotationally symmetrical manner.
- the Gaussian-distributed light 2 ⁇ becomes a light 2 ⁇ having a distribution shifted by 2 ⁇ after being reflected by the signal surface 8a of the optical disc 8 (shifted by ⁇ with respect to the central axis 7c of the objective lens 7).
- the 0th-order Gr diffracted light 2e on the hologram surface 13a also has a light distribution centered on the position 2 ⁇ shifted by 2 ⁇ , and the projection of the aperture of the objective lens 7 along the light beam on the hologram surface 13a.
- the outside of the circle 7a which is a figure, is shielded from light.
- the position 2E is shifted by ⁇ from the dividing line 13Y of the hologram surface 13a. Therefore, the amount of light detected by the detection cell 92 is larger than the amount of light detected by the detection cell 94, and an offset is generated only by the signals ( ⁇ 4 ⁇ 2) obtained by the detection cells 92 and 94.
- the offset amount is about 1Z3 of the prior art.
- the ⁇ 1st-order Gr diffracted light 2e, 2e "on the holodamal surface 13a also has a light distribution centered at position 2 ⁇ shifted by 2 ⁇ , and the objective lens 7
- the outside of the circle 7a which is a projected figure along the light beam on the hologram surface 13a, is shielded from light, so the amount of light detected by the detection cell 92 'is less than the amount of light detected by the detection cell 94'.
- the signal (T 4 '—T2') obtained in the detection cells 92 'and 94' is also offset, but the influence of shading by the circle 7a is less than that in Fig. 5 (a). If it becomes smaller, it works to increase the amount of offset, and when standardized by the detected light intensity, it is about 3.5 times that of Fig. 5 (a), 1.1 to 1.2 compared to the conventional technology. Double An offset occurs.
- the magnitude coefficient k cancels the effect of off-track due to lens shift, and the tracking error signal is not included in the signal ( ⁇ 4'- ⁇ 2 '), so there is no deterioration in detection sensitivity due to computation.
- the tracking error signal ( ⁇ 4— ⁇ ⁇ ⁇ ⁇ 2) due to the 0th-order Gr diffracted light 2e is affected by off-track due to lens shift because of the depth of the guide groove such as DVD-R or DVD-RW. It is limited to optical discs with shallow groove pitch and shallow, and optical discs with large groove pitch with deep guide grooves such as DVD-RAM have almost no effect. This phenomenon is the same for ⁇ 1st order Gr diffracted lights 2e, 2e ".
- Fig. 5 (c) shows the ⁇ 1st order Gr diffracted lights 2e, 2e" and their groove diffracted lights in a DVD-RAM device. Show the state. As shown in Fig.
- FIG. 1 is overlapped in the present embodiment and the first embodiment). (The explanation is omitted because it is duplicated.)
- FIG. 6 (a) shows a light detection pattern formed on a light detector used in the optical disk device according to the second embodiment of the present invention, and a return light with respect to the emitted laser light.
- FIG. 6B is a diagram showing a configuration of a hologram used in the optical disc apparatus.
- FIG. 6B is a diagram showing a state of light distribution on the photodetector.
- FIGS. 6 (a) and 6 (b) show a light detection surface and a hologram surface viewed from the optical disk side.
- the first-order Gr diffracted beams 2e ′ and 2e ′′ on the hologram surface 13a are in the state shown in FIG.
- the hologram surface 13a has two straight lines (13X, 13Y) orthogonal to each other at the intersection 130 between the optical axis L and the hologram surface 13a.
- 134 [This harm has been ij.
- the axis 13X is parallel to the radial direction of the optical disc, and the return light (0th order Gr diffracted light 2e) on the hologram surface 13a is shifted along the axis 13X corresponding to the optical disc radial direction so that the signal of the optical disc 8 Groove diffracted beams 2ep and 2em from the guide groove 8g formed on the surface 8a are superimposed.
- the outline of the groove diffracted light is shown by a broken line, taking the return light from an optical disc of a narrow pitch format such as DVD-R or DVD-RW as an example. Then, when this light passes through the hologram surface 13a, ⁇ 1st-order diffracted light is generated and divided into quadrants 133, 132, 133, and 134, and is divided into the light detection surface 10a on the light detection substrate 10.
- the light detection surface 10a has two straight lines orthogonal to the intersection point 100 of the optical axis L and the light detection surface 10a and parallel to the axis 13X and the axis 13Y.
- comb-like focus detection cells 95 and 96 along axis 10X are alternately arranged on the negative side of axis 10X (detection cells with the same reference numerals are electrically connected).
- the rectangular tracking detection cells 91, 92, 92, 93, 94, 94 are arranged on the positive side of the axis 10X (light detection pattern).
- These tracking detection cells 91, 92, 92, 93, 94, 94 have a 180 ° rotationally symmetric shape around the center of the boundary line of the tracking detection cells 92, 94.
- 92, 94, 94 are aligned in the direction of the axis 10Y, and the tracking detection cells 91, 93 are shifted from each other in the direction of the axis 10Y in the opposite directions along the axis 10X.
- the laser beam 2 emitted from the emission point la of the radiation source 1 travels in a plane parallel to the paper surface in parallel with the axis 10Y, and is reflected by the reflecting mirror 12 in the direction of the optical axis L (through the point 100 and directly onto the paper surface). Reflected in the direction of intersection).
- the + first-order holodiffracted light diffracted by the quadrant 131 of the hologram surface 13a is converted into a light spot 2 dl that falls within the tracking detection cell 91, 1
- the first-order holo diffracted light is diffracted by the quadrant 132 of the hologram surface 13a into the light spot 2D1 straddling the boundary between the focus detection cells 95 and 96, and the first-order holo diffracted light is within the tracking detection cell 92.
- the first-order holo diffracted light is diffracted by the quadrant 133 of the hologram surface 13a into the light spot 2D2 straddling the boundary between the focus detection cells 95 and 96.
- the first-order holo-diffracted light is diffracted by the quadrant 134 of the hologram surface 13a into the light spot 2D3 straddling the boundary between the focus detection cells 95 and 96.
- the light spot 2d4 fits inside the in g detection cell 94, -1 order holo diffracted light, respectively collecting light into a light spot 2D4 across the boundaries of the focus detection cells 95, 96.
- the holo-diffracted light diffracted by the quadrant 131 of the hologram surface 13a is transmitted to the light spot 2dl 'outside the detection cell.
- the holo diffracted light diffracted by the quadrant 132 of the surface 13a is reflected into the light spot 2d2 'that falls inside the tracking detection cell 94, and the holo diffracted light diffracted by the quadrant 133 of the hologram surface 13a is light outside the detection cell.
- the holo diffracted light diffracted by the quadrant 134 of the hologram surface 13a on the spot 2d3 is condensed on the light spot 2d4 contained in the tracking detection cell 94 ′. Further, among the first-order Gr diffracted light 2e "on the hologram surface 13a, the holo diffracted light diffracted by the quadrant 131 of the hologram surface 13a is transferred to the optical spot 2dl" outside the detection cell. The holo diffracted light diffracted by the quadrant 132 falls into the light spot 2d2 "that falls inside the tracking detection cell 92, and the holo diffracted light diffracted by the quadrant 133 on the hologram surface 13a becomes the light spot 2d3 outside the detection cell. In addition, the holo diffracted light diffracted by the quadrant 134 of the hologram surface 13a is condensed on the light spot 2d4 that falls within the tracking detection cell 92, respectively.
- each quadrant 131, 132, 133, 134 of the hologram surface 13a The light spots 2D1, 2D2, 2D3 and 2D4 are the + first-order holo-diffracted light power S, the light spot to be focused 2dl, 2d2, 2d3, and 2d4, point 100 The position is almost point symmetrical.
- the first-order Gr diffracted light 2e, 2e "holo-diffracted light is based on the condensing position of the 0th-order Gr diffracted light 2e holo diffracted light + 1st-order Gr diffracted light 2e
- the holo diffracted light of ' is focused on the brass side of the axis 10Y
- the holo diffracted light of the first-order Gr diffracted light 2e is focused on the position shifted to the negative side of the axis 10Y.
- the focal line in the direction of the axis 10X of the light spots 2D1, 2D2, 2D3, and 2D4 is on either side (the back (the side that moves away from the hologram surface 13a) or near (the hologram surface 13a) of the light detection surface 10a.
- the focal spot in the direction of the axis 10Y of the light spots 2D1 and 2D3 is located behind (or in front of) the light detection surface 10a and the direction of the axis 10Y of the light spots 2D2 and 2D4.
- the focal line is located in front of (or behind) the light detection surface 10a.
- each quadrant 131, 132, 133, 134 of the hologram surface 13a is divided into strip-shaped regions along the axis 13Y, and the holo-diffracted light diffracted by every other strip-shaped region is detected.
- a method of condensing holo diffracted light diffracted by the remaining strip-shaped region in the back of the surface 10a before the light detection surface 10a is also conceivable.
- the present embodiment is different from the first embodiment except that ⁇ 1st order 01: diffracted light 26, 2e "passes over the axis 13X and the method of diffracting light by the hologram is different. Therefore, the detection signal of ⁇ 1st order Gr diffracted light 2e, 2e "is approximately 3.5 times the 0th order Gr diffracted light 2e due to the effect of lens shift (normalized by the detected light intensity). Offset) occurs on the other hand, but no offset occurs for off-track.
- the signal (T4, 1 ⁇ 2 ') obtained in the detection cells 92' and 94 ' To compensate for the remaining off-track effects Is the term of the signal (T4, 1 ⁇ 2 ') obtained in the detection cells 92' and 94 '.
- the same effect as that of the first embodiment can be obtained, and the light spots 2b ′ and 2b ′′ on the signal surface 8a are formed in the guide groove 8g.
- the reproduction signal detected by the optical disc apparatus of the present embodiment includes signal components read by the light spots 2b 'and 2b ". This degrades the quality of the reproduced signal (the signal read by the light spot 2b).
- the light spots 2b 'and 2b "on the signal surface 8a are spread in the optical disk rotation direction.
- the AC component of the signal reproduced by the light spots 2b 'and 2b " is almost eliminated. Therefore, the signal component read by the light spots 2b' and 2b" is read by the light spot 2b.
- the influence on the reproduction signal is also kept sufficiently small.
- FIG. 7 is a diagram showing a state of light distribution on the light detection surface when the focused light is defocused on the signal surface of the optical disc in the second embodiment of the present invention. a) is when the optical disc signal surface is closer to the objective lens, and (b) is when the optical disc signal surface is away from the objective lens.
- FIG. 7 only the light spot on the + first-order holo-diffracted light side is shown, but the light spot on the first-order holo-diffracted light side is the dot of the light spot on the + first-order hoof diffracted light side. The position is almost point-symmetric with respect to 100.
- the optical disc apparatus of the present invention can cancel the influence of the off-track accompanying the lens shift without impairing the detection output of the tracking error signal without adjusting the rotation of the linear grating. It is useful as an optical disk device used for recording and reproduction of optical disks.
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Abstract
Description
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CN2007800130728A CN101421785B (zh) | 2006-04-12 | 2007-03-19 | 光盘装置 |
JP2008509711A JP4751444B2 (ja) | 2006-04-12 | 2007-03-19 | 光ディスク装置 |
US12/296,822 US8045432B2 (en) | 2006-04-12 | 2007-03-19 | Optical disc device |
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JP2006109497 | 2006-04-12 | ||
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US (1) | US8045432B2 (ja) |
JP (1) | JP4751444B2 (ja) |
CN (1) | CN101421785B (ja) |
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JP4722190B2 (ja) * | 2009-01-20 | 2011-07-13 | 三洋電機株式会社 | 光ピックアップ装置および光ディスク装置 |
GB2470554A (en) * | 2009-05-26 | 2010-12-01 | St Microelectronics Ltd | Optical navigation device with housing and optical transmission element to a mousing surface |
GB2470553A (en) * | 2009-05-26 | 2010-12-01 | St Microelectronics Ltd | Optical computer input with single frustrated total internal reflection mousing surface |
US8508721B2 (en) * | 2009-08-18 | 2013-08-13 | The Boeing Company | Multifunction aircraft LIDAR |
JP2012033230A (ja) * | 2010-07-30 | 2012-02-16 | Sanyo Electric Co Ltd | 光ピックアップ装置 |
JP2012094209A (ja) * | 2010-10-26 | 2012-05-17 | Sanyo Electric Co Ltd | 光ピックアップ装置 |
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JP2003331437A (ja) * | 2002-05-09 | 2003-11-21 | Hitachi Ltd | 光ヘッドおよび光ディスク装置 |
JP2004281026A (ja) * | 2002-08-23 | 2004-10-07 | Matsushita Electric Ind Co Ltd | 光ピックアップヘッド装置及び光情報装置及び光情報再生方法 |
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JP2006012213A (ja) * | 2004-06-22 | 2006-01-12 | Sharp Corp | 受発光集積デバイスおよびそれを備える光ピックアップならびに光ディスク装置 |
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JP3549301B2 (ja) | 1995-09-08 | 2004-08-04 | 三菱電機株式会社 | 光ヘッドのトラッキング誤差検出装置 |
WO1997015923A1 (en) * | 1995-10-27 | 1997-05-01 | Matsushita Electric Industrial Co., Ltd. | Optical head |
CN1139918C (zh) * | 1997-02-24 | 2004-02-25 | 三洋电机株式会社 | 光读出装置及使用该装置的光学记录媒体驱动装置 |
JP2000133929A (ja) | 1998-10-27 | 2000-05-12 | Matsushita Electric Ind Co Ltd | リフロー加熱方法及びリフロー装置 |
JP3977234B2 (ja) * | 2002-04-24 | 2007-09-19 | シャープ株式会社 | 光ピックアップ |
US20040228236A1 (en) * | 2003-05-13 | 2004-11-18 | Sharp Kabushiki Kaisha | Optical pickup device |
KR100524986B1 (ko) * | 2003-08-26 | 2005-10-31 | 삼성전자주식회사 | 광픽업 및 이를 채용한 광 기록 및/또는 재생기기 |
US7626900B2 (en) * | 2003-09-24 | 2009-12-01 | Sony Corporation | Optical pickup and disk drive apparatus |
WO2007132974A2 (en) * | 2006-05-12 | 2007-11-22 | Lg Electronics Inc. | Recording/reproducing apparatus and tracking control method |
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2007
- 2007-03-19 CN CN2007800130728A patent/CN101421785B/zh not_active Expired - Fee Related
- 2007-03-19 JP JP2008509711A patent/JP4751444B2/ja not_active Expired - Fee Related
- 2007-03-19 WO PCT/JP2007/055523 patent/WO2007116631A1/ja active Application Filing
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Patent Citations (5)
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JP2003331437A (ja) * | 2002-05-09 | 2003-11-21 | Hitachi Ltd | 光ヘッドおよび光ディスク装置 |
JP2004281026A (ja) * | 2002-08-23 | 2004-10-07 | Matsushita Electric Ind Co Ltd | 光ピックアップヘッド装置及び光情報装置及び光情報再生方法 |
JP2005122869A (ja) * | 2003-09-24 | 2005-05-12 | Sony Corp | 光ピックアップ及びディスクドライブ装置 |
JP2005317063A (ja) * | 2004-04-27 | 2005-11-10 | Matsushita Electric Ind Co Ltd | ホログラム素子および光ピックアップ |
JP2006012213A (ja) * | 2004-06-22 | 2006-01-12 | Sharp Corp | 受発光集積デバイスおよびそれを備える光ピックアップならびに光ディスク装置 |
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CN101421785B (zh) | 2011-07-27 |
JPWO2007116631A1 (ja) | 2009-08-20 |
US20090279403A1 (en) | 2009-11-12 |
US8045432B2 (en) | 2011-10-25 |
CN101421785A (zh) | 2009-04-29 |
JP4751444B2 (ja) | 2011-08-17 |
WO2007116631B1 (ja) | 2008-03-20 |
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