WO2006118082A1 - 光ヘッド装置および光情報処理装置 - Google Patents
光ヘッド装置および光情報処理装置 Download PDFInfo
- Publication number
- WO2006118082A1 WO2006118082A1 PCT/JP2006/308573 JP2006308573W WO2006118082A1 WO 2006118082 A1 WO2006118082 A1 WO 2006118082A1 JP 2006308573 W JP2006308573 W JP 2006308573W WO 2006118082 A1 WO2006118082 A1 WO 2006118082A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- light
- light beam
- sub
- signal
- main
- Prior art date
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 351
- 230000010365 information processing Effects 0.000 title claims description 48
- 238000001514 detection method Methods 0.000 claims description 41
- 230000005540 biological transmission Effects 0.000 claims description 16
- 238000010586 diagram Methods 0.000 description 53
- 238000000034 method Methods 0.000 description 16
- 238000004364 calculation method Methods 0.000 description 12
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 8
- 239000000758 substrate Substances 0.000 description 7
- 230000000903 blocking effect Effects 0.000 description 5
- 230000010287 polarization Effects 0.000 description 5
- 230000003321 amplification Effects 0.000 description 4
- 201000009310 astigmatism Diseases 0.000 description 4
- 230000001427 coherent effect Effects 0.000 description 4
- 238000003199 nucleic acid amplification method Methods 0.000 description 4
- 238000002310 reflectometry Methods 0.000 description 4
- 230000002238 attenuated effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000005498 polishing Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 101150108962 TEPP gene Proteins 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1381—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
- G11B7/12—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
- G11B7/0901—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
Definitions
- the present invention relates to an optical head device for optical recording and Z or reproduction of data, and an optical information processing device equipped with the optical head device.
- DVD Digital Versatile Disc
- FIG. 26 is a diagram showing a conventional optical head device 300. As shown in FIG.
- the optical head device 300 is mounted on an optical information processing device (not shown) that records and reproduces information.
- a tracking error signal is detected by irradiating the optical recording medium 21 with three light beams (see, for example, Patent Document 1).
- light source 1 which is a semiconductor laser element or the like emits a linearly polarized divergent light beam 10 having a wavelength ⁇ force of 05 nm.
- the diverging light beam 10 emitted from the light source 1 is converted into parallel light by a collimating lens 11 having a focal length f 1 of 15 mm and then enters the diffraction grating 12.
- the light beam 10 incident on the diffraction grating 12 is branched into three light beams of 0th order and ⁇ 1st order diffracted light.
- the 0th-order diffracted light is a main light beam 10a for recording and reproducing information Z.
- the ⁇ first-order diffracted light is two sub light beams 10b and 10c used in a differential push-pull (hereinafter referred to as DPP) method for detecting a tracking error (hereinafter referred to as TE) signal.
- DPP differential push-pull
- TE tracking error
- the ratio of the diffraction efficiency of the 0th-order diffracted light 10a and one 1st-order diffracted light 10b or 10c is usually 10: 1 to avoid unnecessary recording by the sub-light beam. It is set to 20: 1, here it is 20: 1.
- the three light beams 10a ⁇ generated by the diffraction grating 12: LOc passes through the polarization beam splitter 13, passes through the quarter wave plate 14, and is circularly polarized. After being converted into light, it is converted into a convergent light beam by an objective lens 15 having a focal length f2 of 2 mm, passes through the transparent substrate 21a of the optical recording medium 21, and is condensed on the information recording layer 21c.
- the optical recording medium 21 includes two information recording layers 21b and 21c. In FIG. 26, the light beam 10 collected by the objective lens 15 is focused on the information recording layer 21c.
- the distance d2 from the light incident surface of the optical recording medium 21 to the information recording layer 21c is 100 ⁇ m, and the distance dl between the information recording layer 21b and the information recording layer 21c is 25 m.
- the period tp (FIG. 27) of the tracks formed in the information recording layers 21b and 21c is 0.32 m.
- the aperture of the objective lens 15 is limited by the aperture 16, and the numerical aperture NA is 0.85.
- the transparent substrate 21a has a thickness of 0.1 mm and a refractive index n of 1.62.
- the equivalent reflectivities of the information recording layers 21b and 21c are about 4 to 8%, respectively.
- the equivalent reflectance means that the optical recording medium 21 is reflected after the light beam is reflected by the information recording layer 21b or 21c when the light amount of the light beam incident on the optical recording medium 21 is 1. It shows the amount of light beam when it is emitted again.
- the information recording layer 21c absorbs or reflects most of the amount of incident light beam.
- the information recording layer 21b has a light amount of about 50% of the incident light beam to reach the information recording layer 21c. And absorbs or reflects the remaining 50% of the light.
- FIG. 27 is a diagram showing the positional relationship between the light beam on the information recording layer 21c and the track.
- the track pitch tp of tracks Tn—l, Tn and Tn + 1 is 0.32 m.
- the sub light beam 10b is condensed between the track Tn-1 and the track Tn
- the sub light beam 10c is condensed between the track Tn and the track Tn + 1.
- the distance U between the main light beam 10a and the sub light beams 10b and 10c is perpendicular to the track U.
- Light beam 10a reflected by information recording layer 21c: LOc passes through objective lens 15 and quarter-wave plate 14 and is converted into linearly polarized light that is 90 degrees different from the forward path, and then polarized beam splits Reflected by data 13.
- the light beams 10a to 10c reflected by the polarization beam splitter 13 pass through a condenser lens 25 having a focal distance f3 of 30 mm, are converted into convergent light, and enter a photodetector 30 through a cylindrical lens 26.
- Astigmatism is imparted to the light beam 10a ⁇ : LOc when passing through the cylindrical lens 26.
- the light detector 30 includes eight light receiving units 30a to 30h, the light receiving units 30a to 30d receive the light beam 10a, the light receiving units 30e to 30f force S the light beam 10b, and the light receiving units 30g to 30h receive the light beam 10c, respectively. Receive light.
- the light receiving units 30a to 30h output electrical signals I30a to I30h (not shown) corresponding to the received light quantity.
- a focus error (hereinafter referred to as FE) signal is obtained by an astigmatism calculation using signals I30a to I30d output from the photodetector 30.
- the FE signal can be obtained by calculating (I 30a + I30c) one (I30b + I30d).
- the TE signal can be obtained by calculation using the DPP method.
- a TE signal can be obtained by calculating ⁇ (I30a + I30d) (I30b + I30c) ⁇ C ′ ⁇ (I30e + I30g) ⁇ (I30f + I30h) ⁇ .
- C is a coefficient determined by the ratio of the diffraction efficiency between the 0th-order diffracted light of the diffraction grating 12 and one 1st-order diffracted light.
- the FE signal and TE signal are amplified and phase-compensated to a desired level, and then supplied to the actuators 31 and 32 for moving the objective lens 15 to perform focus control and tracking control.
- a reproduction signal (hereinafter referred to as an RF signal) indicating information recorded in the information recording layer 21c is obtained by the calculation of I30a + I30b + I30c + I30d.
- Patent Document 1 Japanese Patent Laid-Open No. 3-005927 (pages 5-8, Fig. 2)
- the light beam is reflected by an information recording layer other than the desired information recording layer and then enters the photodetector.
- the optical beams 40a to 40c are light beams that enter the photodetector 30 when the light beams 10a to 10c are reflected by the information recording layer 21b.
- the light beam 40a and the light beam 10b overlap each other, and the light beam 40a and the light beam 10c overlap each other, thereby producing a light and dark distribution due to interference.
- the distribution of brightness and darkness due to this interference varies depending on the surface blur of the optical recording medium 21 and the partial thickness unevenness of the transparent substrate 21a, and affects the TE signal.
- FIG. 29 is a diagram showing a state when a TE signal by the DPP method obtained when the light beams 10a to 10c are scanned in a direction orthogonal to the track is observed with an oscilloscope.
- the TE signal is detected by the conventional optical head device as described above, the amplitude and symmetry of the TE signal fluctuate greatly.
- tracking control is performed using this TE signal, tracking control becomes unstable, and it is difficult to record and reproduce information with high reliability.
- the present invention has been made in view of the above problems, and an object of the present invention is to reduce fluctuations in TE signal amplitude and to record and reproduce information with high reliability and optical information. It is to provide a processing apparatus.
- the optical head device of the present invention includes a light source that emits a light beam, a condensing unit that condenses the light beam on an optical recording medium having a track, and a light beam reflected by the optical recording medium. And an optical head device that receives the branched light beam and outputs a signal corresponding to the received light amount, wherein the reflected light beam is zero-order diffracted light + 1st order diffracted light and 1st order diffracted light, and the reflected light beam includes a first interference part where the 0th order diffracted light and the + 1st order diffracted light interfere, and the 0th order diffracted light and the above described light beam.
- a second interference portion that interferes with the first-order diffracted light, and the branching portion includes a first main region that transmits the first interference portion, a second main region that transmits the second interference portion, and The ratio of transmission of the first interference portion is lower than that of the first main region, and A first sub-region and a second sub-region having a lower rate of transmission of the second interference portion than the second main region, and a longitudinal direction of the first and second interference portions of the cross section of the reflected light beam The first sub-region and the second sub-region are separated from each other by a dividing line extending to the first sub-region, and the branching portion connects the first main light beam transmitted through the first main region and the second main region.
- the branching unit may further include an exchange unit for exchanging a part of the first sub light beam and a part of the second sub light beam.
- the light detection unit includes a first light receiving unit, a second light receiving unit, and a third light receiving unit. And a fourth light receiving portion, wherein the first main light beam is incident on the first light receiving portion, the second main light beam is incident on the second light receiving portion, and the first sub light beam and the The part of the replaced second sub light beam is incident on the same third light receiving unit, and the part of the second sub light beam and the part of the replaced first sub light beam is the same as the fourth light receiving part. Incident on the part.
- the dividing line passes through a position where a central portion of the cross section of the reflected light beam in the branch portion transmits.
- the branch portion further includes a central dummy region that transmits a central portion of a cross section of the reflected light beam, and the branch portion includes a dummy that passes through the central dummy region.
- the reflected light beam is further branched into a light beam, and the dummy light beam does not enter the first to fourth light receiving parts.
- a pair of the replacement units is provided, wherein one of the replacement units is located between the first main region and the central dummy region, and the other of the replacement units is the It is located between the second main area and the central dummy area.
- An optical information processing apparatus includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- An optical information processing apparatus of the present invention is an optical information processing apparatus including the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the first light receiving unit on which the first main light beam is incident outputs a first signal corresponding to the received light amount
- the second light receiving unit on which the second main light beam is incident corresponds to the received light amount.
- the third light receiving section that outputs the second signal and the first sub light beam and a part of the replaced second sub light beam are incident outputs a third signal corresponding to the received light quantity.
- the fourth light receiving unit on which the second sub light beam and a part of the replaced first sub light beam are incident outputs a fourth signal corresponding to the received light amount, and the optical information processing apparatus And a generation unit that generates a tracking error signal, and the generation unit
- a first differential operation unit that generates a first differential signal by calculating a difference between the first signal and the second signal; and a second difference by calculating a difference between the third signal and the fourth signal.
- a second differential operation unit that generates a dynamic signal; an adjustment unit that adjusts the gain of at least one of the first differential signal and the second differential signal;
- a third differential operation unit configured to calculate a difference between the first differential signal and the second differential signal to generate a third differential signal;
- the optical head device of the present invention includes a light source that emits a light beam, a condensing unit that condenses the light beam on an optical recording medium having a track, and a light beam reflected by the optical recording medium. And an optical head device that receives the branched light beam and outputs a signal corresponding to the received light amount, wherein the reflected light beam is zero-order diffracted light + 1st order diffracted light and 1st order diffracted light, and the reflected light beam includes a first interference part where the 0th order diffracted light and the + 1st order diffracted light interfere, and the 0th order diffracted light and the above described light beam.
- a second interference portion that interferes with the first-order diffracted light includes a first main region that transmits the first interference portion, a second main region that transmits the second interference portion, and The ratio of transmission of the first interference portion is lower than that of the first main region, and A first sub-region and a second sub-region having a lower rate of transmission of the second interference portion than the second main region, and a longitudinal direction of the first and second interference portions of the cross section of the reflected light beam
- the first sub-region and the second sub-region are separated by a dividing line extending to the center, and the branch portion further includes a central dummy region through which a central portion of the cross section of the reflected light beam is transmitted.
- the central dummy area is surrounded by the first and second main areas and the first and second sub-areas, and the branch portion is a first main light beam transmitted through the first main area.
- the reflected light beam is branched, and the light detection unit includes a first light receiving unit, a second light receiving unit, a third light receiving unit, and a fourth light receiving unit, and the first main light beam is the first light receiving unit.
- the second main light beam is incident on the second light receiving portion, the first sub light beam is incident on the third light receiving portion, and the second sub light beam is incident on the second light receiving portion.
- the light beam is incident on four light receiving portions, and the dummy light beam is not incident on the first to fourth light receiving portions.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the first light receiving unit on which the first main light beam is incident is a light receiving unit.
- the second light receiving unit that outputs the first signal according to the amount of light and the second main light beam is incident outputs the second signal according to the amount of light received, and the first sub light beam is incident.
- the third light receiving unit outputs a third signal corresponding to the received light amount
- the fourth light receiving unit on which the second sub light beam is incident outputs a fourth signal corresponding to the received light amount
- the apparatus further includes a generation unit that generates a tracking error signal, and the generation unit calculates a difference between the first signal and the second signal to generate a first differential signal.
- a computing unit a second differential computing unit that computes a difference between the third signal and the fourth signal to generate a second differential signal; and the first differential signal and the second differential signal;
- An adjustment unit for adjusting the gain of at least one of the first differential signal and the third differential signal by calculating a difference between the first differential signal and the second differential signal That and a third differential operation unit.
- An optical head device of the present invention includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffraction light beams that are collected on an optical recording medium.
- a condensing unit a branching unit that branches a plurality of diffracted light beams reflected by the optical recording medium; and a light detection unit that receives the plurality of branched diffracted light beams and outputs a signal corresponding to the received light quantity
- the plurality of diffracted light beams includes a main light beam that is zero-order diffracted light and first and second sub-light beams that are first-order or higher-order diffracted light
- the optical head device is further provided with a partial light shielding unit that is provided in an optical path between the light source and the light collecting unit and shields a part of the main light beam.
- the partial light shielding portion shields a portion including a central portion of a cross section of the main light beam.
- the optical recording medium includes a plurality of recording layers, and a part of the main light beam shielded by the partial light shielding unit focuses the main light beam on a predetermined recording layer. Accordingly, the main light beam reflected by the recording layer other than the predetermined recording layer corresponds to a portion incident on the light receiving portion of the light detecting portion.
- the partial light-shielding part shields two parts positioned symmetrically with respect to a central part of a cross section of the main light beam.
- the optical recording medium includes a plurality of recording layers
- the light detection unit includes a first light receiving unit and second and second symmetrically arranged with respect to the first light receiving unit.
- the partial light shielding unit further includes a collimator lens provided in an optical path between the light source and the partial light shielding unit, which converts a light beam emitted from the light source into a parallel light beam. Shields part of the parallel light beam.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the optical head device of the present invention includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffracted light beams that are collected on an optical recording medium.
- a condensing unit a branching unit that branches a plurality of diffracted light beams reflected by the optical recording medium; and a light detection unit that receives the plurality of branched diffracted light beams and outputs a signal corresponding to the received light quantity
- the plurality of diffracted light beams includes a main light beam that is zero-order diffracted light and first and second sub-light beams that are first-order or higher-order diffracted light
- the diffracting section generates a first partial diffracting section that generates more main light beams than the first and second sub-light beams, and more first and second sub-light beams than the main light beams.
- a second partial diffraction section to be generated, and That.
- the pair of second partial diffractive parts includes a pair of the second partial diffractive parts, and the pair of second partial diffractive parts is symmetrically positioned with respect to a central part of a cross section of the light beam incident on the diffractive part. It is location.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the optical head device of the present invention includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffracted light beams that are collected on an optical recording medium.
- the plurality of diffracted light beams are zero-order diffracted light.
- first and second sub light beams that are first-order or higher-order diffracted light, and the diffracting section transmits the main light beam more than the first and second sub light beams.
- the second partial diffraction portion is not provided with a diffraction grating.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the optical head device of the present invention is an optical head device that is mounted on a device that generates a tracking error signal using a main light beam and a sub light beam, and the optical head device uses the main light beam.
- a first light source that emits light
- a second light source that emits the sub light beam
- a light collecting unit that condenses the main light beam and the sub light beam onto an optical recording medium; and the light reflected by the optical recording medium.
- a branching unit that branches the main light beam and the sub light beam; and a light detection unit that receives the branched main light beam and the sub light beam and outputs a signal corresponding to the received light amount,
- the main light beam and the sub light beam have different wavelengths.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the optical head device of the present invention includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffracted light beams that are collected on an optical recording medium.
- a condensing unit ; a branching unit that branches a plurality of diffracted light beams reflected by the optical recording medium; and a light detection unit that receives the plurality of branched diffracted light beams and outputs a signal corresponding to the received light quantity
- the diffraction unit has a diffraction grating, and the optical head device swings the diffraction unit in a direction perpendicular to a direction in which a groove of the diffraction grating extends. It further has a moving part.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- An optical head device of the present invention includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffracted light beams that are collected on an optical recording medium.
- a condensing unit ; a branching unit that branches a plurality of diffracted light beams reflected by the optical recording medium; and a light detection unit that receives the plurality of branched diffracted light beams and outputs a signal corresponding to the received light quantity
- the optical recording medium includes a plurality of recording layers, the coherence distance of the light beam emitted from the light source is L, and the distance between two recording layers is d, It is characterized in that 2′d′n> L, where n is the refractive index of the medium located between the two recording layers.
- An optical information processing apparatus includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the branch portion of the optical head device includes the first main region through which the first interference portion of the light beam is transmitted, the second main region through which the second interference portion is transmitted, and the first main region.
- the first and second sub-regions have a lower rate of transmission of the first interference portion than the second main region and a lower rate of transmission of the second interference portion than the second main region.
- the branching unit includes a first main light beam transmitted through the first main region, a second main light beam transmitted through the second main region, a first sub light beam transmitted through the first sub region, and a second sub light beam. The light beam is split into the second sub-light beam that has passed through the region.
- the branching unit further includes an exchange unit for exchanging a part of the first sub light beam and a part of the second sub light beam.
- an exchange unit for exchanging a part of the first sub-light beam and a part of the second sub-light beam so as to be incident on the light detection unit.
- the optical head device includes a partial light blocking unit that blocks a part of the main light beam.
- a part of the main light beam corresponding to the portion incident on the light receiving portion of the light detecting portion is shielded by the partial light shielding portion.
- [3B] A diagram showing the relationship between the photodetector and the light beam according to the first embodiment of the present invention.
- FIG. 4 A diagram showing a signal generation unit according to the first embodiment of the present invention.
- FIG. 5 A diagram showing a TE signal according to the first embodiment of the present invention.
- FIG. 6A A diagram showing a partial light shielding plate according to Embodiment 2 of the present invention.
- [6B] A diagram showing the relationship between the photodetector and the light beam according to the second embodiment of the present invention.
- FIG. 7A A diagram showing a partial light shielding plate according to Embodiment 3 of the present invention.
- [7B] A diagram showing the relationship between the photodetector and the light beam according to the third embodiment of the present invention.
- FIG. 8 shows an optical head device according to Embodiment 4 of the present invention.
- [10B] A diagram showing the relationship between the photodetector and the light beam according to the fifth embodiment of the present invention.
- FIG. 11 shows an optical head device according to Embodiment 6 of the present invention.
- FIG. 12 A diagram showing a relationship between a photodetector and a light beam according to Embodiment 6 of the present invention.
- FIG. 13 A diagram showing an optical head device according to Embodiment 7 of the present invention.
- FIG. 14 shows an optical head device according to Embodiment 8 of the present invention.
- FIG. 15A shows a diffraction grating according to Embodiment 8 of the present invention.
- ⁇ 15B A diagram showing the relationship between the photodetector and the light beam according to the eighth embodiment of the present invention.
- ⁇ 16] A diagram showing the optical head device according to the ninth embodiment of the present invention.
- ⁇ 17 Diagram showing an optical head device according to the tenth embodiment of the present invention.
- FIG. 18 shows a hologram element according to Embodiment 10 of the present invention.
- FIG. 19 A diagram showing a relationship between a photodetector and a light beam and a signal generation unit according to Embodiment 10 of the present invention.
- FIG. 20 shows an example of the distribution of light incident on the hologram element according to Embodiment 10 of the present invention.
- FIG. 22 is a diagram illustrating an example of an offset variation of a tracking signal according to Embodiment 10 of the present invention.
- FIG. 22 is a diagram illustrating an example of an offset variation of a tracking signal in a conventional optical head device.
- ⁇ 24 A diagram showing the relationship between the photodetector and the light beam according to the eleventh embodiment of the present invention.
- ⁇ ⁇ 25 A diagram showing an example of the tracking signal offset variation according to the eleventh embodiment of the present invention.
- FIG. 26 shows a conventional optical head device.
- FIG.29 Diagram showing the state of a conventional TE signal
- FIGS. 1-10 A first embodiment of an optical head device and an optical information processing device according to the present invention will be described with reference to FIGS.
- FIG. 1 is a diagram showing an optical information processing apparatus 100 of the present embodiment.
- the optical information processing apparatus 100 is a recording / reproducing apparatus, a reproducing apparatus, a recording apparatus, an editing apparatus, or the like that optically records information on the optical recording medium 21 and Z or reproduces information from the optical recording medium 21.
- the optical recording medium 21 is an optical disk medium.
- the optical information processing apparatus 100 includes an optical head device 50 that irradiates the optical recording medium 21 with a light beam, a transfer controller 51 that moves the optical head device 50, and a motor 52 that rotates the optical recording medium 21.
- the amplifier 54 that amplifies the signal
- the demodulator 56 that demodulates the data
- the output unit 57 that outputs the signal
- the detector 58 that detects the address signal and the like
- the first controller that controls the operation of the optical information processing apparatus 100 1 and second control units 53 and 55 and a system control unit 59.
- the optical head device 50 (also referred to as an optical pickup device) irradiates the optical recording medium 21 with a light beam having a wavelength ⁇ of 405 nm, and reproduces information recorded on the optical recording medium 21.
- the transfer controller 51 moves the optical head device 50 in the radial direction of the optical recording medium 21 in order to record or reproduce information at a desired position of the optical recording medium 21.
- the motor 52 drives and rotates the optical recording medium 21.
- the first control unit 53 controls the optical head device 50, the transfer controller 51, and the motor 53.
- the amplifier 54 amplifies the output signal of the optical head device 50.
- the second control unit 55 outputs servo signals such as a focus error (hereinafter referred to as FE) signal and a tracking error (hereinafter referred to as TE) signal necessary for recording / reproducing information to / from the optical recording medium 21 from the output of the amplifier 54. Generate from signal.
- the second control unit 55 outputs the generated servo signal to the first control unit 53.
- the signal input to the second control unit 55 is an analog signal.
- the analog signal is digitized (binarized).
- the signal generated by the second control unit 55 is output to the first control unit 53, the demodulation unit 56, the detection unit 58, and the system control unit 59.
- the demodulator 56 analyzes the digital signal output from the second controller 55, reconstructs the original video data, music data, etc., and the reproduced signal generated by the reconstruction is also output from the output unit 57. Is output.
- the detection unit 58 also detects an address signal or the like from the signal power output from the second control unit 55 and outputs it to the system control unit 59.
- the system control unit 59 identifies the optical recording medium based on the physical format information read from the optical recording medium 21 and the optical recording medium manufacturing information (optical recording medium management information), and performs recording / reproduction. Decodes the conditions and controls the entire optical information processing apparatus 100.
- the first control unit 53 drives and controls the transfer controller 51 in accordance with instructions from the system control unit 12.
- the transfer controller 51 moves the optical head device 50 to a desired position on the information recording layer 21c, and the optical head device 50 records and reproduces information on the information recording layer of the optical recording medium 21.
- FIG. 2 is a diagram showing the optical head device 50.
- the optical head device 50 includes a light source 1, a collimating lens 11, a diffraction unit 61, a partial light shielding plate 62, a polarizing beam splitter 63, a quarter-wave plate 14, an objective lens 15, and an aperture. 16, actuators 31 and 32, a detection lens 64, a cylindrical lens 65, and a photodetector 30.
- the light source 1 is a semiconductor laser element or the like, and emits a linearly polarized divergent light beam 10 having a wavelength ⁇ of about 405 nm.
- the divergent light beam 10 emitted from the light source 1 is converted into parallel light by the collimator lens 11 having a focal length fl of 15 mm, and then enters the diffraction unit 61.
- the light beam 10 incident on the diffraction section 61 having a diffraction grating is branched into three optical beams 10a, 10b, and 10c of 0th-order and first-order diffracted light.
- the 0th-order diffracted light is a main light beam 10a that performs information recording Z reproduction.
- the ⁇ first-order diffracted light is two sub-light beams 10b and 10c used in the differential push-pull (hereinafter referred to as DPP) method for detecting the TE signal.
- the sub light beams 10b and 10c can be first-order or higher diffracted light.
- diffraction efficiency of 0th-order diffracted light 10a and one 1st-order diffracted light 10b or 10c The ratio is normally set to 10: 1 to 20: 1 to avoid unnecessary recording by the sub light beam, and is 20: 1 here.
- the three light beams 10a ⁇ : LOc generated by the diffraction section 61 are partially shielded when passing through the partial light shielding plate (partial light shielding section) 62 (details will be described later).
- the optical recording medium 21 includes two information recording layers 21b and 21c. In FIG. 2, the light beam 10 collected by the objective lens 15 is focused on the information recording layer 21c. When recording / reproducing information on / from the information recording layer 2 lb, the light beam 10 is focused on the information recording layer 21b.
- the incident surface force of light of the optical recording medium 21 is set such that the distance d2 to the information recording layer 21c is 100 m, and the distance dl between the information recording layer 21b and the information recording layer 21c is 25 m.
- the period tp (FIG. 27) of the tracks formed in the information recording layers 21b and 21c is 0.32 m.
- the aperture of the objective lens 15 is limited by the aperture 16, and the numerical aperture NA is 0.85.
- the transparent substrate 21a has a thickness of 0.1 mm and a refractive index n of 1.62.
- the equivalent reflectivities of the information recording layers 21b and 21c are about 4-8%, respectively.
- the equivalent reflectance refers to the optical recording medium 21 again after the light beam is reflected by the information recording layer 21b or 21c when the light quantity of the light beam incident on the optical recording medium 21 is 1.
- the light intensity of the light beam when it is emitted is shown.
- the information recording layer 21c absorbs or reflects most of the amount of incident light beam, but the information recording layer 21b is about 50% of the incident light beam to reach the information recording layer 21c. The remaining amount of light is absorbed or reflected.
- the light beam 10a reflected by the information recording layer 21c The LOc passes through the objective lens 15 and the quarter-wave plate 14 and is converted into linearly polarized light that differs by 90 degrees from the forward path. The light is reflected at 63 (branch). The light beams 10a to 10c reflected by the polarization beam splitter 63 are converted into convergent light by the detection lens 64 having a focal length f3 of 50 mm, and enter the photodetector 30 through the cylindrical lens 65. Astigmatism is imparted to the light beam 10a to LOc when passing through the cylindrical lens 65. The light beams 10a to 10c are applied to the information recording layer 21.
- the light beam 10 on the photodetector 30 becomes a circle of least confusion.
- the driving current of the light source 1 is modulated at a high frequency of 400 MHz by the high frequency superimposing element 66, and the light beam 10 emitted from the light source 1 has a plurality of wavelengths. Since the light beam 10 emitted from the light source 1 has a plurality of wavelengths, the distribution of light and darkness due to interference is reduced.
- the photodetector 30 outputs a signal corresponding to each light quantity of the received light beams 10a to 10c.
- FIG. 3A is a front view of the partial light shielding plate 62 that shields a part of the main light beam 10a.
- the partial light shielding plate 62 is provided in the optical path between the light source 1 and the objective lens 15. In the example shown in FIG. 2, it is provided between the diffraction section 61 and the polarization beam splitter 63.
- the light beam 10 emitted from the light source 1 is converted into a parallel light beam by the collimator lens 11 provided in the optical path between the light source 1 and the partial light shielding plate 62 and branched by the diffraction unit 61.
- the partial light shielding plate 62 shields a part of the main light beam 10a which is a parallel light beam. By blocking the parallel light beam, the alignment of the main light beam 10a and the partial light shielding plate 62 is facilitated.
- a dotted line 70 shows a cross section of the main light beam 10a obtained by projecting the main light beam 10a when passing through the aperture 16 onto the partial light shielding plate 62.
- the light shielding part 71 is located in the central part of the partial light shielding plate 62, and light is shielded by absorbing the light beam that attempts to pass through this part, that is, the part including the central part of the cross section of the main light beam 10a.
- FIG. 3B is a diagram showing the light beams 10a to 10c incident on the photodetector 30 when the light beams 10a to 10c are focused on the desired information recording layer 21c.
- the main light beam 10a reflected by the information recording layer 21b enters the photodetector 30 as a light beam 72a.
- the light shielding region 73 near the center of the light beam 72a is a portion blocked by the light shielding portion 71 of the partial light shielding plate 62.
- the light shielding region 73 is aligned with the light receiving portions 30a to 30h included in the photodetector 30.
- a portion corresponding to a portion incident on the light receiving portions 30a to 30h (that is, the light shielding region 73) is shielded by the partial light shielding plate 62.
- the light beams 10b and 10c focused on the light receiving section 30e-30h should not overlap with the light beam 72a. Thus, interference can be prevented. As a result, the amplitude fluctuation of the TE signal can be reduced. By detecting TE signals stably, information can be recorded and reproduced with high reliability.
- the detection system has a magnification of 25 times.
- the distance dl between the information recording layer 21b and the information recording layer 21c is at least 20 m
- the refractive index of the information recording layer 21b and the transparent substrate 21a is 1.60.
- the diameter of the light beam 72a shown in FIG. 3B is 0.8 lmm.
- the size of the area where the light receiving portions 30a to 30h are arranged is 120 111 360 111.
- a light-shielding region 73 having a size of about 120 X 360 m or more is formed for an optical beam having a diameter of 0.81 mm! Since the diameter of the cross section (dotted line 70) of the light beam 10a when passing through the partial light shielding plate 62 is 3.4 mm, the light shielding portion 71 may have a size of about 1.5 mm X O. 5 mm or more.
- the photodetector 30 includes eight light receiving units 30a to 30h, and the light receiving units 30a to 30d receive the main light beam 10a.
- the light receiving units 30e and 30f receive the sub light beam 10b, and the light receiving units 30g and 30h receive the sub light beam 10c.
- the light receiving units 30a to 30h output electrical signals I30a to I30h (not shown) corresponding to the received light amounts.
- An FE signal is obtained using the signals I30a to I30d output from the photodetector 30.
- the detection method of the FE signal is an astigmatism method, and can be obtained by, for example, the calculation of (I30a + I30c)-(I30b + I30d).
- the TE signal detection method is the DPP method, which can be obtained, for example, by calculating ⁇ (I30a + I30d) (I30b + I30c) ⁇ C ′ ⁇ (130e + I30g) (I30f + I30h) ⁇ .
- C is a coefficient determined by the ratio of the diffraction efficiency of the 0th-order diffracted light and one 1st-order diffracted light of the diffractive portion 61.
- the FE signal and the TE signal are amplified and phase-compensated to a desired level, and then supplied to the actuators 31 and 32 for moving the object lens 15, for focus control and tracking control. .
- the information recorded on the information recording layer 21c is displayed.
- the reproduction signal (hereinafter referred to as RF signal) is obtained by the calculation of I30a + I30b + I30c + I30d.
- the TE signal When the TE signal is detected by the phase difference method, it may be generated by comparing the output timing of the signals I30a to I30d.
- the TE signal generation method based on the phase difference method is often used when using an optical recording medium having a read-only information recording layer. To do.
- FIG. 4 is a diagram illustrating a signal generation unit 55a that generates a TE signal.
- the signal generation unit 55a can be provided in the second control unit 55.
- the signals I30a and I30d output from the light receiving units 30a and 30d are subjected to power calculation by the adding unit 80.
- the signals I30b and I30c output from the light receiving units 30b and 30c are calorified by the adding unit 81.
- the signals output from the adder 80 and the adder 81 are input to the differential operation unit 82 and subjected to differential operation.
- a signal ⁇ (I30a + I30d)-(I30b + I3Oc) ⁇ which is a differentially calculated signal is a TE signal detected by a so-called push-pull method.
- the TE signal When the TE signal is detected by a simple push-pull method, if the objective lens 15 is made to follow the tracking according to the eccentricity of the optical recording medium 21, an offset variation corresponding to the tracking follow-up occurs in the TE signal.
- the signals I30f and 13 Oh output from the light receiving units 30f and 30h are added by the adding unit 83, and the signals I30e and I 30g output from the light receiving units 30e and 30g are added by the adding unit 84. .
- the signals output from the adders 83 and 84 are input to the differential calculator 85 and subjected to differential calculation.
- the signal output from the differential operation unit 85 is input to the variable gain amplification unit 86, and is amplified or attenuated to a desired signal strength. The amplification at this time is C.
- the signal output from the variable gain amplifying unit 86 has the same variation as the offset variation corresponding to the tracking tracking that the signal output from the differential operation unit 82 has.
- the differential operation unit 87 receives the signal output from the differential operation unit 82 and the signal output from the variable gain amplification unit 86 and performs the differential operation, thereby outputting from the differential operation unit 82. Reduces offset fluctuation according to tracking tracking of the signal. As a result, the signal output from the differential operation unit 87 becomes a TE signal with almost no offset fluctuation even after tracking tracking. However, in this state, the reflectance of the information recording layers 21b and 21c and the optical recording medium 21 are not illuminated.
- the output signal of the differential operation unit 87 is input to the division unit 88 to obtain a constant amplitude.
- the signals I30a to I30d output from the light receiving units 30a to 30d are added by the adding unit 89 and then input to the dividing unit 88 as a signal for performing division.
- the signal output from the adder 89 is a signal proportional to the reflectance of the information recording layers 21b and 21c and the intensity of the light beam applied to the optical recording medium 21. For this reason, the signal output from the division unit 88 is a TE signal having a desired constant amplitude.
- the optical recording medium 21 includes two information recording layers 21b and 21c.
- Light beam 10a ⁇ When information is recorded / reproduced with the LOc focused on the information recording layer 21c, the light beam is also reflected on the information recording layer 2 lb and then enters the photodetector 30.
- the light beam 72a (FIG. 3B) is a light beam incident on the photodetector 30 when the light beam 10a is reflected by the information recording layer 21b. Since the light beams 10a to 10c are focused on the information recording layer 21c, the information recording layer 21b is largely defocused. Therefore, the light beam 72a is also largely defocused on the light detector 30.
- the photodetector 30 receives both the main light beam 10a and the sub light beams 10b and 10c. Since the optical head device 50 includes the partial light shielding plate 62, the light beam 10b and the light beam 72a do not overlap, and the light beam 10c and the light beam 72a do not overlap. For this reason, there is no light and dark distribution due to interference caused by conventional optical head devices.
- FIG. 5 is a diagram showing a state when the TE signal obtained by the optical information processing apparatus 100 of the present embodiment is observed with an oscilloscope.
- the TE signal amplitude TEpp and symmetry are both very stable, enabling stable tracking control.
- the partial light shielding plate 62 is disposed in the forward path of the light beam 10a. Since the partial light shielding plate 62 shields a part of the light beam 10a, the energy of the light beam 10a is attenuated to some extent. Therefore, in order to obtain a stable reproduction signal having a high SZN ratio, the light source 1 needs to emit a high-energy light beam 10 in consideration of energy attenuation.
- the partial light shielding plate 62 is arranged on the return path after the light beam 10a is reflected by the information recording layer.
- the partial light shielding plate 62 is disposed in the forward path of the light beam 10a, and the laser light 10a after the energy is attenuated by the partial light shielding plate 62 is recorded in the information recording medium. The above problem does not occur because the recording layer is irradiated.
- the power shielding unit 71 reflects or diffracts a part of the main light beam 10a as an example in which the light shielding part 71 of the partial light shielding plate 62 absorbs a part of the main light beam 10a. In this case, the same effect can be obtained.
- FIG. 6A is a diagram showing the partial light shielding plate 91 of the present embodiment.
- the partial light shielding plate 91 is mounted on the optical head device 50 instead of the partial light shielding plate 62 (FIG. 2).
- the partial light shielding plate 91 no interference occurs even if the position of the light shielding region of the laser beam is shifted.
- the difference of the partial light shielding plate 91 from the partial light shielding plate 62 is that the width of the light shielding portion 92 is increased along the direction in which the objective lens 15 moves for tracking tracking.
- FIG. 6B is a diagram showing the light beams 10a to 10c incident on the photodetector 30 when the light beams 10a to 10c are focused on the desired information recording layer 21c.
- the main light beam 10a reflected by the information recording layer 21b enters the photodetector 30 as a light beam 93a.
- the light shielding region 94a near the center of the light beam 93a is a portion blocked by the light shielding portion 92 of the partial light shielding plate 91.
- the width of the light shielding portion 92 is increased, the light receiving portions 30a to 30h are accommodated in the light shielding region 94a even if the position of the objective lens 15 is shifted due to tracking tracking. Even if the position of the objective lens 15 is shifted due to tracking tracking, the light beam 93a does not overlap with the light beams 10b and 10c, so that interference can be prevented.
- the moving range of the objective lens 15 in which the tracking signal can be stably obtained can be set larger.
- a force indicating a design in which the amount of movement of the objective lens 15 is assumed to be 100 ⁇ m is not limited to this.
- the present invention is not limited to this, and the width of the light shielding portion 92 is increased. Even if it is narrowed, the same effect can be obtained.
- FIG. 7A is a diagram showing the partial light shielding plate 101 of the present embodiment.
- the partial light shielding plate 101 is mounted on the optical head device 50 instead of the partial light shielding plate 62 (FIG. 2).
- the partial light shielding plate 101 differs from the partial light shielding plate 62 in that two light shielding portions 102 and 103 are provided at positions corresponding to the light receiving portions that receive the sub light beams 10b and 10c. Similarly to the light shielding part 92 (FIG. 6A), the widths of the light shielding parts 102 and 103 are increased along the direction in which the objective lens 15 moves by tracking tracking.
- a dotted line 70 shows a cross section of the main light beam 10a obtained by projecting the main light beam 10a when passing through the aperture 16 onto the partial light shielding plate 62.
- the light shielding parts 102 and 103 shield two parts located symmetrically with respect to the central part of the cross section of the main light beam 10a.
- the light receiving units 30e to 30f and the light receiving units 30g to 30h are arranged symmetrically with respect to the light receiving units 30a to 30d.
- FIG. 7B is a diagram showing the light beams 10a to 10c incident on the photodetector 30 when the light beams 10a to 10c are focused on the desired information recording layer 21c.
- the main light beam 10a reflected by the information recording layer 21b enters the photodetector 30 as a light beam 104a.
- the sub-light beams 10b and 10c reflected by the information recording layer 21b also enter the photodetector 30, but are omitted for the sake of simplicity.
- the light shielding regions 105a and 106a included in the light beam 104a are portions blocked by the light shielding portions 102 and 103.
- the light shielding areas 105a and 106a are aligned with the light receiving portions 30e to 30h.
- portions corresponding to the portions incident on the light receiving portions 30e to 30h that is, the light shielding regions 105a and 106a
- the light shielding regions 105a and 106a are shielded by the light shielding portions 102 and 103.
- Interference can be prevented by making the light beams 10b and 10c focused on the light receiving portions 30e to 30h and the light beam 104a not overlap each other.
- fluctuations in the amplitude of the TE signal can be reduced.
- By detecting the TE signal stably, information can be recorded and reproduced with high reliability.
- the conditions of the optical system are the same as the example described in the description of the first embodiment. Design so that the light beam 104a and the light beams 10b and 10c do not overlap even if the objective lens moves by tracking 100 m.
- the light receiving sections 10e to 10h that receive the sub light beams 10b and 10c are located at both ends 1Z3 of the light receiving sections 10a to LOh. Therefore, the vertical width of the light-shielding portion 102 is set to 0.5 mm, the vertical width of the light-shielding portion 103 is set to 0.5 mm, and the two light-shielding portions are arranged with an interval of 0.5 mm therebetween.
- the width in the horizontal direction of the light shielding portions 102 and 103 may be 0.9 mm shown in the description of the second embodiment.
- FIG. 8 is a diagram showing the optical head device 110 of the present embodiment.
- the optical head device 110 is mounted on the optical information processing device 100 instead of the optical head device 50 (FIG. 2).
- the optical head device 110 includes a diffractive portion 111 instead of the diffractive portion 61 and the partial light shielding plate 62, and the other constituent elements are the same as those of the optical head device 50.
- the diffractive portion 111 partially has a region having a high diffraction efficiency, thereby functioning as a partial light shielding portion.
- FIG. 9 is a diagram showing the diffraction section 111.
- the diffracting unit 111 generates the first partial diffracting unit 114 that generates the main light beam 10a more than the sub light beams 10b and 10c, and the first partial diffracting unit 114 that generates the sub light beams 10b and 10c more than the main light beam 10a.
- Two partial diffraction sections 112 and 113 are provided.
- the second partial diffraction portions 112 and 113 are high diffraction efficiency portions with high diffraction efficiency.
- the diffraction gratings of the high diffraction efficiency sections 112 and 113 have deeper grooves than the other regions (first partial diffraction section 114).
- the diffraction gratings of the 0th order diffracted light 10a and one 1st order diffracted light 10b or 10c The ratio of folding efficiency is 0: 1.
- the ratio of the diffraction efficiency of the first partial diffraction section 114 is 20: 1 as in the first embodiment.
- the positional relationship between the arrangement position of the pair of high diffraction efficiency sections 112 and 113 in the diffraction section 111 and the light beam 10 is the same as the arrangement position of the pair of light shielding sections 102 and 103 (Fig. 7A) and the main light beam 1 Oa. It is the same as the positional relationship with.
- the pair of high diffraction efficiency portions 112 and 113 are positioned symmetrically with respect to the central portion of the cross section of the light beam 10 incident on the diffraction portion 111.
- the high diffraction efficiency parts 112 and 113 have the same design as the light-shielding parts 102 and 103, with a width of 0.9 mm, a vertical width of 0.5 mm, and an interval of 0.5 mm.
- a light shielding region similar to the light shielding regions 105a and 106a (FIG. 7B) can be formed, so that no interference occurs on the light receiving portions 30a to 30h of the photodetector 30.
- the amplitude fluctuation of the TE signal can be reduced, and information can be recorded and reproduced with high reliability.
- the diffractive part 111 When the diffractive part 111 is used, the light shielding part and the diffractive part can be integrated, so that the optical head 110 can be reduced in size and the number of manufacturing steps can be reduced.
- FIGS. 10A to 10B Next, a fifth embodiment of the optical head device according to the present invention will be described with reference to FIGS. 10A to 10B.
- FIG. 10A is a diagram showing the diffraction unit 121 of the present embodiment.
- the diffractive part 121 is a diffractive part 111.
- the diffraction unit 121 records desired information. Interference caused by the sub-light beams 10b and 10c reflected by the information recording layer other than the layer is prevented.
- FIG. 10A is a front view of the diffractive portion 121.
- the diffraction unit 121 may be used in place of the force diffraction unit 61 (FIG. 2) used in place of the diffraction unit 111 (FIG. 8).
- the ratio of the diffraction efficiency between the main light beam 10a and one sub light beam 10b or 10c in the first partial diffraction unit 125 of the diffraction unit 121 is the same as that of the diffraction unit 61 (Fig. 2). 20: 1.
- the main light beam 10a includes a second partial diffraction section (low diffraction efficiency section) 122 having a higher ratio of generating the main light beam than the first partial diffraction section 125.
- the diffraction grating groove is not formed in the low diffraction efficiency portion 122, and the ratio of the diffraction efficiency in this case is about 1: 0.
- the low diffraction efficiency portion 122 is disposed at a position where the central portion of the cross section of the light beam 10 incident on the diffraction portion 121 is transmitted. All the laser light 10 incident on the low diffraction efficiency part 122 is not diffracted but outputted as a main light beam 10a which is zero-order light.
- FIG. 10B shows the light beams 10a to 10c incident on the photodetector 30 when the light beams 10a to 10c are focused on the desired information recording layer 21c.
- the sub light beams 10b and 10c reflected by the information recording layer 21b enter the photodetector 30 as light beams 123b and 123c.
- the main light beam 10a reflected by the information recording layer 21b also enters the photodetector 30, but is omitted for the sake of simplicity.
- the light shielding region 124b near the center of the light beam 123b the light is blocked because the low diffraction efficiency portion 122 has no diffraction grating groove.
- the light shielding region 124c near the center of the light beam 123c the light is blocked because the low diffraction efficiency portion 122 has no diffraction grating groove. Since the incident positions of the light shielding regions 124b and 124c are based on the sub light beams 10b and 10c, they are shifted in the vertical direction in FIG. 10B.
- the low diffraction efficiency portion 122 is designed so that the light receiving portions 10a to LOh are contained within the region where the light shielding regions 124b and 124c overlap (indicated by white in FIG. 10B).
- the light shielding regions 124b and 124c are located in the range of the light receiving portions 30a to 30h even if their positions are shifted due to tracking tracking of the objective lens 15.
- the optical beams 123b and 123c do not overlap with the light beams 10a to: LOc and do not cause interference. Thereby, the amplitude fluctuation of the TE signal can be reduced. Stable detection of TE signal By doing so, information can be recorded and reproduced with high reliability.
- the conditions of the optical system are the same as the example described in the description of Embodiment 1.
- the positions of the light beams 123b and 123c on the photodetector 30 are shifted by 120 / zm with respect to the main light beam reflected by the information recording layer 21b and incident on the photodetector 30. Therefore, the required length in the vertical direction of the light shielding regions 124b and 124c is 360 m + 120 ⁇ 2 and 600 m. When this is converted on the diffraction part 121, it becomes about 2.5 mm.
- the horizontal direction is 0.9 mm so that the objective lens 15 may move 100 / z m by tracking tracking o
- Use of the low diffraction efficiency portion 122 can prevent occurrence of interference due to the sub light beams 10b and 10c reflected by the information recording layer other than the desired information recording layer.
- the low diffraction efficiency unit 122 can be combined with the optical head devices of the first to third embodiments, and the TE signal fluctuation due to interference can be more completely suppressed.
- the low diffraction efficiency portion 122 may be formed with a shallow groove as a diffraction grating.
- the low diffraction efficiency unit 122 only needs to have a lower diffraction efficiency than the first partial diffraction unit 125.
- FIG. 11 is a diagram showing the optical head device 130 of the present embodiment.
- the optical head device 130 In the optical head device 130, different light source forces are generated for the main light beam and the sub light beam.
- the optical head device 130 is mounted on the optical information processing device 100 instead of the optical head device 50 (FIG. 2).
- the optical head device 130 includes a light source 131, a diffraction unit 133, and a beam splitter 134 instead of the diffraction unit 61 and the partial light shielding plate 62, and the other components are the same as those of the optical head device 50.
- the light source 1 emits a light beam 10 as a main light beam.
- the light source 131 emits a light beam 132 as a sub light beam.
- the light beam 10 and the light beam 132 have different wavelengths.
- the light beam 132 emitted from the light source 131 is diffracted by the diffraction section 133, and two sub light beams 132b and 132c are output.
- the light beam 10 and the two sub light beams are directed almost in the same direction by the beam splitter 134, and the collimator lens 11 and the beam splitter 63 are As described above, the light is condensed on the optical recording medium 21 by the objective lens 15.
- the sub light beams 132b and 132c are condensed at the same positions as the sub light beams 10b and 10c shown in FIG.
- the three light beams reflected and diffracted by the optical recording medium 21 pass through the objective lens 15 again, are reflected by the beam splitter 63, are collected by the detection lens 64, pass through the cylindrical lens 65, and enter the photodetector 30. .
- FIG. 12 is a diagram showing the light beams 10, 132b, and 132c that enter the photodetector 30 when the light beams 10, 132b, and 132c are focused on the desired information recording layer 21c.
- the main light beam 10 reflected by the information recording layer 21b enters the photodetector 30 as a light beam 40a.
- the sub-light beams 132b and 132c reflected by the information recording layer 21b are also omitted for simplicity of description of the force incident on the photodetector 30.
- the light beam 40a and the light beams 132b and 132c have overlapping forces. Since the wavelengths are different from each other, no interference occurs. Thereby, the amplitude fluctuation of the TE signal can be reduced. By stably detecting TE signals, information can be recorded and reproduced with high reliability.
- the optical head device 130 since it is not necessary to provide a light shielding portion or the like in the light forward path, interference can be prevented without affecting signal reproduction, and a TE signal can be stably obtained. .
- FIG. 11 is a diagram showing the optical head device 140 of the present embodiment.
- the optical head device 140 In the optical head device 140, different light source forces are generated for the main light beam and the sub light beam.
- the optical head device 140 is mounted on the optical information processing device 100 instead of the optical head device 50 (FIG. 2).
- the optical head device 140 includes light sources 141 and 142 and a beam splitter 145 instead of the light source 131 and the diffraction unit 133, and other components are the optical head device 130. Is the same.
- the light source 1 emits a light beam 10 as a main light beam.
- the light sources 141 and 142 emit light beams 143 and 144 as sub light beams.
- the light beam 10, the light beam 143, and the light beam 144 have different wavelengths.
- the light beams 143 and 144 emitted from the light sources 141 and 142 are the beam splitters 14. At 5 is pointed in one direction. Further, the light beam 10, the light beam 143, and the light beam 144 are directed in substantially the same direction by the beam splitter 134. The subsequent operation of the optical head device 140 is the same as that of the optical head device 130.
- the light beam 10 Since the light beam 10, the light beam 143, and the light beam 144 have different wavelengths, interference on the light detector 30 does not occur. As a result, the amplitude fluctuation of the TE signal can be reduced. By stably detecting TE signals, information can be recorded and reproduced with high reliability.
- the optical head device 140 since it is not necessary to provide a light blocking portion or the like in the light forward path, interference can be prevented without affecting signal reproduction, and a TE signal can be obtained stably. .
- FIG. 14 An eighth embodiment of the optical head device according to the present invention will be described with reference to FIG. 14, FIG. 15A and FIG. 15B.
- FIG. 14 is a diagram showing an optical head device 150 of the present embodiment.
- the optical head device 150 is mounted on the optical information processing device 100 instead of the optical head device 50 (FIG. 2).
- the optical head device 150 includes a diffractive portion 151 and an actuator 152 instead of the diffractive portion 61 and the partial light shielding plate 62, and other components are the same as those of the optical head device 50.
- the actuator 152 functions as a swinging unit that swings the diffraction unit 151 in a direction perpendicular to the direction in which the groove of the diffraction grating of the diffraction unit 151 extends. By oscillating the diffraction part 151, the interference fringes are averaged over time.
- FIG. 15A is a front view of the diffractive portion 151, and shows the moving direction of the diffractive portion 151.
- the grooves of the diffraction grating are formed in the horizontal direction, and the diffracted light is generated in the vertical direction.
- the moving direction 153 is the same direction (longitudinal direction) as the direction in which the diffracted light is generated.
- FIG. 12 is a diagram showing the light beams 10a to 10c incident on the photodetector 30 when the light beams 10a to 10c are focused on the desired information recording layer 21c.
- the main light beam 10 reflected by the information recording layer 21b enters the photodetector 30 as a light beam 40a.
- the sub-light beams 10b and 10c reflected by the information recording layer 21b are also incident on the photodetector 30 for the sake of simplicity.
- the optical system conditions are the same as the example described in the description of the first embodiment.
- the pitch of the diffraction grating of the diffraction section 151 is 162 / z m. If the tracking servo gain intersection is 5 kHz and the TE signal only needs to be averaged at 5 kHz, 81 111 should be moved by 0.2 msec in order to reverse the brightness of the interference fringes. That is, if the diffraction part 151 is swung at an average speed of 0.4 m Zsec.
- the optical head device 150 since it is not necessary to provide a light blocking portion or the like in the light forward path, interference can be prevented without affecting signal reproduction, and a TE signal can be obtained stably. .
- FIG. 16 is a diagram showing an optical head device 160 of the present embodiment.
- the optical head device 160 is mounted on the optical information processing device 100 instead of the optical head device 50 (FIG. 2).
- the optical head device 160 includes a light source 161 with low coherence instead of the light source 1 and does not include the partial light shielding plate 62.
- Other components of the optical head device 160 are the same as those of the optical head device 50.
- the light beam 10 emitted from the light source 161 passes through a distance that differs by a distance of 2 X dl Xn when reflected by the information recording layer 2c and when reflected by the information recording layer 21c.
- dl is the distance between the information recording layers
- n is the refractive index of the intermediate substance between the information recording layers.
- the coherent distance L force of the light beam 10 emitted from the light source 161 may be reduced so that interference does not occur due to this difference in distance. That is, 2'dl'n> L is sufficient.
- the length of the coherent distance L can be set by the element design of the light source 161.
- the length of the coherent distance L can also be set by adjusting the harmonic current superimposed on the drive current supplied to the light source 1601. [0132] As an example, if the minimum distance of dl is 20 ⁇ m and n is 1.60, the coherent distance L may be less than 64 ⁇ m.
- the optical head device 160 since it is not necessary to provide a light blocking portion or the like in the light forward path, interference can be prevented without affecting signal reproduction, and a TE signal can be obtained stably. .
- FIG. 17 is a diagram showing an optical head device 170 of the present embodiment.
- the optical head device 170 is mounted on the optical information processing device 100 instead of the optical head device 50 (FIG. 2).
- the optical head device 170 includes a photodetector 173 instead of the photodetector 30, and further includes a hologram element 171.
- the optical head device 170 does not include the diffraction unit 61 and the partial light shielding plate 62.
- Other components of the optical head device 160 are the same as those of the optical head device 50.
- the optical head device 170 employs a one-beam tracking method to stabilize the detected tracking signal.
- the light beam 10 emitted from the light source 1 passes through the collimator lens 11 and the beam splitter 63 and is condensed on the optical recording medium 21 by the objective lens 15.
- the light beam 10 reflected and diffracted by the optical recording medium 21 passes through the objective lens 15 again, is reflected by the beam splitter 63, and enters the hologram element (branching unit) 171.
- the light beam 10 is divided into regions by the hologram element 171, and a part of the light beam 10 is diffracted to become diffracted light 172.
- the light beam 10 and the diffracted light beam 172 are collected by the detection lens 64, pass through the cylindrical lens 65, and enter the light detector 173.
- FIG. 18 is a front view of hologram element 171.
- FIG. A cross section of the light beam 10 incident on the hologram element 171 is indicated by a dotted line 174.
- the light beam 10 is diffracted when reflected by the track of the optical recording medium 21, and includes 0th-order diffracted light, + first-order diffracted light, and first-order diffracted light.
- the light beam 10 includes a first interference portion 175 where the 0th-order diffracted light and the + first-order diffracted light interfere, and a second interference portion 176 where the 0th-order diffracted light and the first-order diffracted light interfere.
- Hologram element 171 is divided into a plurality of regions.
- the hologram element 171 includes a first main region 171A through which the first interference portion 175 passes and a second main region through which the second interference portion 176 passes.
- the first main region 171A and the second main region 171B are arranged symmetrically with the central portion of the hologram element 171 as a reference.
- the first sub-regions 171C and 171D include a replacement unit 171G
- the second sub-regions 171E and 171F include a replacement unit 171H. Details of the replacement units 171G and 171H will be described later.
- the first sub-regions 171C and 171D are arranged so as to surround the outer periphery of the first main region 171A in a C shape.
- the second sub-regions 171E and 171F are arranged so as to surround the outer periphery of the second main region 171B in a C shape.
- the rate of transmission of the first interference portion 175 is lower than that of the first main region 171A, and the second interference portion 176 is transparent of the second main region 171B. This is a region with a low rate.
- the first and second interference portions 175 and 176 hardly transmit the first and second sub-regions 171C to 171F.
- the first sub-regions 171C and 17 1D and the second sub-regions 171E and 171F are separated by a dividing line 178.
- the dividing line 178 extends in the longitudinal direction of the first and second interference portions 175 and 176 in the cross section of the light beam 10, and the extension line of the dividing line 178 passes through the position where the central portion of the cross section of the light beam 10 is transmitted.
- the direction in which the dividing line 178 extends is a direction substantially parallel to the track direction when the track on the optical recording medium 21 is projected onto the hologram element 171.
- the hologram element 171 further includes a central dummy region 17II through which the central portion of the cross section of the light beam 10 is transmitted.
- Fig. 19 is a diagram showing the photodetector 173 and a signal generation unit 55b that generates a TE signal.
- the signal generation unit 55b can be provided in the second control unit 55 (FIG. 1).
- hologram element 171 diffracts and splits light beam 10 into first and second main light beams 172A and 172B and first and second sub light beams 172C to 172F.
- the first main light beam 172A is a light beam that has passed through the first main region 171A.
- the second main light beam 172B is a light beam that has passed through the second main region 171B.
- the first sub light beams 172C and 172D are light beams transmitted through the first sub regions 171C and 171D.
- the second sub light beams 172E and 172F are light beams transmitted through the second sub regions 171E and 171F.
- the light beam 10 transmitted through the central dummy area 1711 is received by the photodetector 173. ⁇ Enters I 73a to 173d.
- Hologram element 171 includes replacement units 171G and 171H that diffract light beam 10 so that a part of first sub light beams 172C and 172D and a part of second sub light beams 172E and 172F are interchanged. Further prepare.
- Replacement unit 171G is arranged in first sub-regions 171C and 171D.
- the replacement unit 171H is disposed in the second sub-regions 171E and 171F.
- the replacement unit 171G is disposed between the first main region 171A and the central dummy region 1 711, and the replacement unit 171H is disposed between the second main region 171B and the central dummy region 1 711.
- the photodetector 173 includes a first light receiving unit 173e, a second light receiving unit 173f, a third light receiving unit 173g, and a fourth light receiving unit 173h.
- the first main light beam 172A is incident on the first light receiving unit 173e.
- the second main light beam 172B is incident on the second light receiving unit 173f.
- the first sub light beams 172C and 172D and the replaced part 172H of the second sub light beam are incident on the same third light receiving unit 173g.
- the second sub light beams 172E and 172F and the part of the replaced first sub light beam 172G are incident on the same fourth light receiving unit 173h.
- the light beam 10, which is a dummy light beam that has passed through the central dummy region 1711, does not enter the first light receiving unit 173e to the fourth light receiving unit 173h but enters the light receiving units 173a to 173d.
- the signals obtained by receiving the light beams 172C, 172D, and 172H were added with the same polarity, and the light beams 172E, 172F, and 172G were received. Add signals with the same polarity. In this way, a part 172G of the first sub-light beam and a part 172H of the second sub-light beam are exchanged across the dividing line 178 and light is received for calculation.
- a cross-track signal can be obtained by differential operation 171AI-171BI of the signal corresponding to the main area.
- the differential operation of the signal corresponding to the sub-region is (171CI + 171DI + 171HI)-(171EI + 171FI + 171GI).
- first light receiving unit 173e outputs a first signal 173el corresponding to the received light quantity.
- the second light receiving unit 173f outputs a second signal 173 ⁇ corresponding to the received light quantity.
- the third light receiving unit 1 73g outputs a third signal 173gl corresponding to the received light quantity.
- the fourth light receiving unit 173h outputs a fourth signal 173hl corresponding to the amount of received light.
- Differential operation section 190 calculates the difference between signal 173el and signal 173 ⁇ and outputs differential signal 1901.
- the differential signal 1901 is a signal mainly including a track crossing component.
- the differential signal 1901 causes the objective lens 15 to follow the tracking according to the eccentricity of the optical recording medium 21, an offset fluctuation occurs according to the tracking tracking.
- differential operation unit 191 output the differential signal 1911 by calculating the difference between the signal 173 8 1 and the signal 173,111.
- the differential signal 1911 is input to the variable gain amplifying unit 192, and the gain of the differential signal 1911 is adjusted to amplify or attenuate to a desired signal strength.
- the amplification degree at this time is k.
- the signal 1921 output from the variable gain amplifying unit 192 has the same fluctuation as the offset fluctuation corresponding to the tracking of the differential signal 1901.
- the gain adjustment may be performed on the differential signal 1901.
- the differential calculation unit 193 reduces the offset variation of the differential signal 1901 by calculating the difference between the differential signal 1901 and the signal 1921.
- the differential signal 1931 output from the differential operation unit 193 is a TE signal with almost no offset variation even after tracking tracking. Since the signal intensity of the differential signal 1931 changes in accordance with the reflectivity of the information recording layers 21b and 21c and the intensity of the light beam applied to the optical recording medium 21, the differential signal 1931 is input to the division unit 194. To a constant amplitude. Signals 173al to 173dl output from the light receiving units 173a to 173d are added by an adding unit 195. The addition signal 1951 output from the addition unit 195 is input to the division unit 194 as a signal for performing division.
- the addition signal 1951 is a signal proportional to the reflectivity of the information recording layers 21b and 21c and the intensity of the light beam applied to the optical recording medium 21, and the signal 1941 output from the division unit 194 is a TE signal having a desired intensity. It becomes.
- the intensity distribution of strength and weakness is caused by diffraction at the edge of the aperture of a processing mark of an optical element having a cylindrical surface or a toric surface (such as a beam shaper that corrects the intensity distribution of an optical beam).
- polishing by rotational movement cannot be used for processing the element surface or mold surface, and polishing by movement using two axes is necessary, and processing traces parallel to the axis are required. Tends to remain. Since the direction in which the light passing through the processing mark is refracted is slightly shifted, an intensity distribution of vertical stripes or horizontal stripes is generated. Even when such an optical element is arranged in the optical path, the optical head apparatus can suppress the offset of the TE signal by mounting the hologram element 171, and a tracking signal can be stably obtained.
- FIG. 21 shows an example of a change in the offset of the TE signal when the objective lens 15 is moved in the optical head device on which the hologram element 171 is mounted.
- FIG. 22 shows an example of a change in the offset of the TE signal when the objective lens is moved in the conventional optical head apparatus.
- signals corresponding to the light beams transmitted through the regions 171C, 171D, and 171G are added.
- signals corresponding to the light beams transmitted through the regions 171E, 171F, and 171H are added. For this reason, when the intensity distribution of light intensity moves, the fluctuation cannot be suppressed, and the TE signal offset changes abruptly.
- the TE signal offset changes by about 15% as the lens moves 100 ⁇ m.
- the change is suppressed to about 5% at 100 m.
- the light beams 10 and 172A to 172H are condensed by the detection lens 64 to receive the light receiving unit 173a.
- the detection lens 64 receives the light receiving unit 173a.
- FIG. 23 is a diagram showing the hologram element 200 of the present embodiment.
- the hologram element 200 is mounted on the optical head device 170 instead of the hologram element 171 (FIG. 18).
- FIG. 23 is a front view of hologram element 200.
- FIG. A cross section of the light beam 10 incident on the hologram element 200 is indicated by a dotted line 174.
- the light beam 10 includes a first interference portion 175 and a second interference portion 176.
- the hologram element 200 (branch portion) is divided into a plurality of regions.
- the hologram element 200 includes a first main region 200A through which the first interference portion 175 is transmitted, a second main region 200B through which the second interference portion 176 is transmitted, first subregions 200C and 200D, a second subregion 200E and With 200F.
- the first main region 200A and the second main region 200B are arranged symmetrically with the central portion of the hologram element 200 as a reference.
- the first sub-regions 200C and 200D are arranged along the longitudinal direction of the first and second interference portions 175 and 176 in the cross section of the light beam 10 so as to sandwich the first main region 200A.
- the first sub-regions 200E and 200F are arranged along the longitudinal direction of the first and second interference portions 175 and 176 so as to sandwich the second main region 200B.
- the rate of transmission of the first interference portion 175 is lower than that of the first main region 200A, and the second interference portion 176 is transparent of the second main region 200B. This is a region with a low rate.
- the first and second interference portions 175 and 176 hardly transmit the first and second sub-regions 200C to 200F.
- the first sub-regions 200C and 200D and the second sub-regions 200E and 200F are separated by a dividing line 203.
- the dividing line 203 extends in the longitudinal direction of the first and second interference portions 175 and 176 in the cross section of the light beam 10, and the extended line of the dividing line 203 passes through the position where the central portion of the cross section of the light beam 10 is transmitted.
- the direction in which the dividing line 203 extends is the optical recording medium This is a direction substantially parallel to the track direction when the track on 21 is projected onto the hologram element 200.
- the hologram element 200 further includes a central dummy region 200G through which the central portion of the cross section of the light beam 10 passes.
- Central dummy area 200G is surrounded by dividing lines 201 and 202 and main areas 200A and 200B. Dividing lines 201 and 202 extend across main areas 200A and 200B. The sub-regions 200C to 200F are arranged outside the dividing lines 201 and 202. The central dummy area 200G is located so as to include the central portion of the hologram element 200, and is surrounded by the sub areas 200C to 200F and the main areas 200A and 200B.
- FIG. 24 is a diagram showing the photodetector 173.
- hologram element 200 diffracts and splits light beam 10 into first and second main light beams 204A and 204B and first and second sub light beams 204C to 204F.
- the first main light beam 204A is a light beam that has passed through the first main region 200A.
- the second main light beam 204B is a light beam that has passed through the second main region 200B.
- the first sub light beams 204C and 204D are light beams transmitted through the first sub regions 200C and 200D.
- the second sub light beams 204E and 204F are light beams transmitted through the second sub regions 200E and 200F.
- the light beam 10 transmitted through the central dummy region 200G enters the light receiving portions 173a to 173d.
- the first main light beam 204A is incident on the first light receiving unit 173e.
- the second main light beam 204B is incident on the second light receiving unit 173f.
- the first sub light beams 204C and 204D are incident on the third light receiving unit 173g.
- the second sub light beams 204E and 204F are incident on the fourth light receiving portion 173h.
- the light beam 10, which is a dummy light beam transmitted through the central dummy region 200G, does not enter the first light receiving unit 173e to the fourth light receiving unit 173h but enters the light receiving units 173a to 173d.
- each of the light receiving units 173a to 173h outputs signals 173al to 173hl corresponding to the received light quantity.
- the calculation method of the signals 173al to 173hl is the same as the method described with reference to FIG.
- FIG. 25 shows an example of a change in the offset of the TE signal when the objective lens 15 is moved in the optical head device on which the hologram element 200 is mounted.
- the TE signal offset is suppressed to about 3% even when the lens of 100 m is moved.
- the lateral length of the cross section of light beam 10 overlapping each of main regions 200A and 200B is 30% of the diameter of light beam 10.
- the width of the laterally narrow portion of the central dummy region 200G is 40% of the light beam diameter.
- the NA of the objective lens 15 is 0.85
- the track pitch is 0.32 ⁇ m
- the wavelength of the laser beam is 405 nm
- the width of each of the interference regions 175 and 176 is about 25% of the light beam diameter.
- the lateral length of the cross section of the light beam 10 overlapping each of the main regions 200A and 200B is the light beam It has been 30% of 10 diameters.
- this ratio indicates the offset of the tracking signal generated at the boundary between the area where the information is recorded on the optical recording medium 21 and the area where the information is not recorded. It's also a good rate to keep down.
- the optimal length of the cross section of the light beam 10 that overlaps each of the main areas 200A and 200B is (interference area width) +0 to 5%. 0 to 5% represents the ratio to the light beam diameter.
- the light beams 10 and 204A to 204F are collected by the detection lens 64 and are incident on the light receiving portions 173a to 173h, thereby further suppressing interference between the regular light beam and stray light and detecting the photodetector.
- the area of the light receiving surface 173 can be reduced.
- the optical head device of the present invention includes a light source that emits a light beam, a condensing unit that condenses the light beam on an optical recording medium having a track, and the optical recording medium.
- An optical head device comprising: a branching unit that branches the reflected light beam; and a light detection unit that receives the branched light beam and outputs a signal corresponding to the amount of received light.
- the light beam includes 0th-order diffracted light, + first-order diffracted light, and first-order diffracted light
- the reflected light beam is a first interference part where the 0th-order diffracted light and the + first-order diffracted light interfere with each other.
- the branching part includes a first main region through which the first interference part is transmitted, and the second interference part is A second main region that transmits through, and the first interference portion is more than the first main region.
- a first sub-region and a second sub-region having a lower transmission ratio and a lower transmission ratio of the second interference portion than the second main region, and the first and second sub-sections of the reflected light beam.
- the first sub-region and the second sub-region are separated from each other by a dividing line extending in the longitudinal direction of the interference portion, and the branch portion includes a first main light beam transmitted through the first main region; Reflected by the second main light beam transmitted through the second main region, the first sub light beam transmitted through the first sub region, and the second sub light beam transmitted through the second sub region.
- the light beam is further branched, and the branching unit further includes a replacement unit that replaces a part of the first sub-light beam and a part of the second sub-light beam.
- the light detection unit includes a first light receiving unit, a second light receiving unit, and a third light receiving unit. And a fourth light receiving portion, wherein the first main light beam is incident on the first light receiving portion, the second main light beam is incident on the second light receiving portion, and the first sub light beam and the The part of the replaced second sub light beam is incident on the same third light receiving unit, and the part of the second sub light beam and the part of the replaced first sub light beam is the same as the fourth light receiving part. Incident on the part.
- the dividing line passes through a position where a central part of a cross section of the reflected light beam in the branching portion is transmitted.
- the branch portion further includes a central dummy region that transmits a central portion of a cross section of the reflected light beam, and the branch portion includes a dummy that passes through the central dummy region.
- the reflected light beam is further branched into a light beam, and the dummy light beam does not enter the first to fourth light receiving parts.
- a pair of the replacement units is provided, wherein one of the replacement units is located between the first main region and the central dummy region, and the other of the replacement units is the It is located between the second main area and the central dummy area.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- An optical information processing apparatus of the present invention is an optical information processing apparatus including the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the first light receiving unit on which the first main light beam is incident outputs a first signal corresponding to the received light amount
- the second light receiving unit on which the second main light beam is incident corresponds to the received light amount.
- the third light receiving section that outputs the second signal and the first sub light beam and a part of the replaced second sub light beam are incident outputs a third signal corresponding to the received light quantity.
- the fourth light receiving unit on which the second sub light beam and a part of the replaced first sub light beam are incident outputs a fourth signal corresponding to the received light amount, and the optical information processing apparatus And a generation unit that generates a tracking error signal, and the generation unit
- a first differential operation unit that generates a first differential signal by calculating a difference between the first signal and the second signal; and a second difference by calculating a difference between the third signal and the fourth signal.
- a second differential operation unit that generates a dynamic signal; an adjustment unit that adjusts the gain of at least one of the first differential signal and the second differential signal;
- a third differential operation unit configured to calculate a difference between the first differential signal and the second differential signal to generate a third differential signal;
- the optical head device of the present invention includes a light source that emits a light beam, a condensing unit that collects the light beam on an optical recording medium having a track, and a light beam reflected by the optical recording medium. And an optical head device that receives the branched light beam and outputs a signal corresponding to the received light amount, wherein the reflected light beam is zero-order diffracted light + 1st order diffracted light and 1st order diffracted light, and the reflected light beam includes a first interference part where the 0th order diffracted light and the + 1st order diffracted light interfere, and the 0th order diffracted light and the above described light beam.
- a second interference portion that interferes with the first-order diffracted light includes a first main region that transmits the first interference portion, a second main region that transmits the second interference portion, and The ratio of transmission of the first interference portion is lower than that of the first main region, and A first sub-region and a second sub-region having a lower rate of transmission of the second interference portion than the second main region, and a longitudinal direction of the first and second interference portions of the cross section of the reflected light beam
- the first sub-region and the second sub-region are separated by a dividing line extending to the center, and the branch portion further includes a central dummy region through which a central portion of the cross section of the reflected light beam is transmitted.
- the central dummy area is surrounded by the first and second main areas and the first and second sub-areas, and the branch portion is a first main light beam transmitted through the first main area.
- the reflected light beam is branched, and the light detection unit includes a first light receiving unit, a second light receiving unit, a third light receiving unit, and a fourth light receiving unit, and the first main light beam is the first light receiving unit.
- the second main light beam is incident on the second light receiving portion, the first sub light beam is incident on the third light receiving portion, and the second sub light beam is incident on the second light receiving portion.
- the light beam is incident on four light receiving portions, and the dummy light beam is not incident on the first to fourth light receiving portions.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the first light receiving unit on which the first main light beam is incident is a receiver.
- the second light receiving unit that outputs the first signal according to the amount of light and the second main light beam is incident outputs the second signal according to the amount of light received, and the first sub light beam is incident.
- the third light receiving unit outputs a third signal corresponding to the received light amount
- the fourth light receiving unit on which the second sub light beam is incident outputs a fourth signal corresponding to the received light amount
- the apparatus further includes a generation unit that generates a tracking error signal, and the generation unit calculates a difference between the first signal and the second signal to generate a first differential signal.
- a computing unit a second differential computing unit that computes a difference between the third signal and the fourth signal to generate a second differential signal; and the first differential signal and the second differential signal;
- An adjustment unit for adjusting the gain of at least one of the first differential signal and the third differential signal by calculating a difference between the first differential signal and the second differential signal That and a third differential operation unit.
- the optical head device of the present invention includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffracted light beams that are collected on an optical recording medium.
- a condensing unit a branching unit that branches a plurality of diffracted light beams reflected by the optical recording medium; and a light detection unit that receives the plurality of branched diffracted light beams and outputs a signal corresponding to the received light quantity
- the plurality of diffracted light beams includes a main light beam that is zero-order diffracted light and first and second sub-light beams that are first-order or higher-order diffracted light
- the optical head device is further provided with a partial light shielding unit that is provided in an optical path between the light source and the light collecting unit and shields a part of the main light beam.
- the partial light shielding portion shields a portion including a central portion of a cross section of the main light beam.
- the optical recording medium includes a plurality of recording layers, and a part of the main light beam shielded by the partial light-shielding unit focuses the main light beam on a predetermined recording layer. Accordingly, the main light beam reflected by the recording layer other than the predetermined recording layer corresponds to a portion incident on the light receiving portion of the light detecting portion.
- the partial light-shielding part shields two parts positioned symmetrically with respect to a central part of a cross section of the main light beam.
- the optical recording medium includes a plurality of recording layers
- the light detection unit includes a first light receiving unit and second and second symmetrically arranged with respect to the first light receiving unit.
- the partial light shielding unit is further provided with a collimator lens provided in an optical path between the light source and the partial light shielding unit, which converts a light beam emitted from the light source into a parallel light beam. Shields part of the parallel light beam.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the optical head device includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffraction light beams that are collected on an optical recording medium.
- a condensing unit a branching unit that branches a plurality of diffracted light beams reflected by the optical recording medium; and a light detection unit that receives the plurality of branched diffracted light beams and outputs a signal corresponding to the received light quantity
- the plurality of diffracted light beams includes a main light beam that is zero-order diffracted light and first and second sub-light beams that are first-order or higher-order diffracted light
- the diffracting section generates a first partial diffracting section that generates more main light beams than the first and second sub-light beams, and more first and second sub-light beams than the main light beams.
- a second partial diffraction section to be generated, and That.
- the pair of second partial diffractive parts includes a pair of second partial diffractive parts, and the pair of second partial diffractive parts are symmetrically positioned with respect to a central part of a cross section of a light beam incident on the diffractive part. It is location.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the optical head device of the present invention includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffracted light beams that are collected on an optical recording medium.
- the plurality of diffracted light beams are zero-order diffracted light.
- first and second sub light beams that are first-order or higher-order diffracted light, and the diffracting section transmits the main light beam more than the first and second sub light beams.
- the second partial diffraction section is not provided with a diffraction grating.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the optical head device of the present invention is an optical head device mounted on a device that generates a tracking error signal using a main light beam and a sub light beam, and the optical head device uses the main light beam.
- a first light source that emits light
- a second light source that emits the sub light beam
- a light collecting unit that condenses the main light beam and the sub light beam onto an optical recording medium; and the light reflected by the optical recording medium.
- a branching unit that branches the main light beam and the sub light beam; and a light detection unit that receives the branched main light beam and the sub light beam and outputs a signal corresponding to the received light amount,
- the main light beam and the sub light beam have different wavelengths.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the optical head device of the present invention includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffraction light beams that are collected on an optical recording medium.
- a condensing unit ; a branching unit that branches a plurality of diffracted light beams reflected by the optical recording medium; and a light detection unit that receives the plurality of branched diffracted light beams and outputs a signal corresponding to the received light quantity
- the diffraction unit has a diffraction grating, and the optical head device swings the diffraction unit in a direction perpendicular to a direction in which a groove of the diffraction grating extends. It further has a moving part.
- the optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- the optical head device of the present invention includes a light source that emits a light beam, a diffraction unit that generates a plurality of diffraction light beams from the light beam, and the plurality of diffracted light beams that are collected on an optical recording medium.
- a condensing unit ; a branching unit that branches a plurality of diffracted light beams reflected by the optical recording medium; and a light detection unit that receives the plurality of branched diffracted light beams and outputs a signal corresponding to the received light quantity
- the optical recording medium includes a plurality of recording layers, the coherence distance of the light beam emitted from the light source is L, and the distance between two recording layers is d, It is characterized in that 2′d′n> L, where n is the refractive index of the medium located between the two recording layers.
- An optical information processing apparatus of the present invention includes the above-described optical head device and a control unit that controls the optical head device based on a signal output from the light receiving unit.
- optical head device and the optical information processing device of the present invention are particularly useful in the technical field of performing optical recording and Z or reproduction of data.
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Recording Or Reproduction (AREA)
- Optical Head (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2007514720A JP4954871B2 (ja) | 2005-04-27 | 2006-04-24 | 光ヘッド装置および光情報処理装置 |
US11/912,469 US8107346B2 (en) | 2005-04-27 | 2006-04-24 | Optical head device and optical information processing device |
CN2006800147813A CN101171629B (zh) | 2005-04-27 | 2006-04-24 | 光头装置及光信息处理装置 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2005129268 | 2005-04-27 | ||
JP2005-129268 | 2005-04-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2006118082A1 true WO2006118082A1 (ja) | 2006-11-09 |
Family
ID=37307882
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2006/308573 WO2006118082A1 (ja) | 2005-04-27 | 2006-04-24 | 光ヘッド装置および光情報処理装置 |
Country Status (4)
Country | Link |
---|---|
US (1) | US8107346B2 (ja) |
JP (1) | JP4954871B2 (ja) |
CN (2) | CN101171629B (ja) |
WO (1) | WO2006118082A1 (ja) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008198336A (ja) * | 2007-01-18 | 2008-08-28 | Matsushita Electric Ind Co Ltd | 光学ヘッド、光ディスク装置、コンピュータ、光ディスクプレーヤおよび光ディスクレコーダ |
JP2008262642A (ja) * | 2007-04-13 | 2008-10-30 | Victor Co Of Japan Ltd | 光ピックアップ装置 |
JP2010097663A (ja) * | 2008-10-17 | 2010-04-30 | Sharp Corp | 光ピックアップ装置 |
EP2202732A1 (en) * | 2008-12-23 | 2010-06-30 | Thomson Licensing | Apparatus and method for reading and apparatus for reading and writing holograms |
EP1942500B1 (en) * | 2007-01-08 | 2010-06-30 | Samsung Electronics Co., Ltd. | Optical pickup including unit to remove crosstalk in multi-layered disk, and optical recording and/or reproducing apparatus including the optical pickup |
US7983134B2 (en) * | 2008-02-21 | 2011-07-19 | Lg Electronics Inc. | Method and apparatus for recording/reproducing data on/from a recording medium |
US8223613B2 (en) | 2008-01-21 | 2012-07-17 | Hitachi Media Electronics Co., Ltd. | Optical pickup device and optical disc apparatus |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4481365B2 (ja) * | 2007-05-30 | 2010-06-16 | 三菱電機株式会社 | 光ヘッド装置及び光ディスク装置 |
JP4784663B2 (ja) * | 2009-02-24 | 2011-10-05 | ソニー株式会社 | 光ピックアップ及び光ディスク装置 |
WO2011048733A1 (ja) * | 2009-10-21 | 2011-04-28 | パナソニック株式会社 | 光ヘッド装置、光情報装置及び情報処理装置 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH041933A (ja) * | 1990-04-18 | 1992-01-07 | Matsushita Electric Ind Co Ltd | 光学ヘッド |
JPH04119531A (ja) * | 1990-09-10 | 1992-04-21 | Mitsubishi Electric Corp | 光ピックアップ装置 |
JPH0547016A (ja) * | 1991-08-13 | 1993-02-26 | Asahi Optical Co Ltd | 光デイスク装置の信号検出系 |
JPH08306057A (ja) * | 1995-05-11 | 1996-11-22 | Matsushita Electric Ind Co Ltd | 光学ヘッド |
JPH1173658A (ja) * | 1997-06-30 | 1999-03-16 | Matsushita Electric Ind Co Ltd | 光学ヘッド及び、情報記録・再生装置 |
JPH11353670A (ja) * | 1998-06-10 | 1999-12-24 | Fujitsu Ltd | 光学装置,トラッキング装置,及び光ディスク装置 |
Family Cites Families (27)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4817074A (en) * | 1985-12-19 | 1989-03-28 | Nec Corporation | Method and apparatus for detecting the focusing state and positioning accuracy of a light beam directed onto an optical disk tracking guide in an optical recording system |
JPH035927A (ja) | 1989-06-01 | 1991-01-11 | Sony Corp | 光学記録および/または再生装置 |
US5278401A (en) | 1991-08-13 | 1994-01-11 | Asahi Kogaku Kogyo Kabushiki Kaisha | Optical disc apparatus having five light receiving areas for detecting focus error and tracking error |
JPH05151593A (ja) * | 1991-11-26 | 1993-06-18 | Nippon Columbia Co Ltd | 光ピツクアツプ |
AU714000B2 (en) * | 1995-06-12 | 1999-12-16 | Sony Corporation | Optical pickup |
FR2758340B1 (fr) * | 1997-01-16 | 1999-02-12 | Vetrotex France Sa | Procede et dispositif de fabrication de plaques composites |
JPH10241188A (ja) * | 1997-02-24 | 1998-09-11 | Sanyo Electric Co Ltd | 光ピックアップ装置およびそれを備えた光学記録媒体駆動装置 |
US6185167B1 (en) | 1997-06-30 | 2001-02-06 | Matsushita Electric Industrial Co., Ltd. | Optical head and information recording and reproduction apparatus |
JP3547610B2 (ja) * | 1998-03-27 | 2004-07-28 | パイオニア株式会社 | 体積ホログラフィックメモリ光情報記録再生装置 |
JP3443668B2 (ja) * | 1998-04-30 | 2003-09-08 | 富士通株式会社 | 収差補正方法及び収差補正装置 |
JP2000228020A (ja) * | 1999-02-05 | 2000-08-15 | Sony Corp | 光ディスク駆動装置、光ディスク駆動方法および光ディスク装置 |
DE60041679D1 (de) * | 1999-03-15 | 2009-04-16 | Panasonic Corp | Lichtsammelelement, Verfahren zur Aufzeichnung und Wiedergabe der Informationen und optischer Kopf |
DE60038872D1 (de) * | 1999-09-23 | 2008-06-26 | Koninkl Philips Electronics Nv | Verfahren zum unmittelbaren schreiben oder lesen von dateien auf ein plattenähnliches aufzeichnungsmedium |
JP2001351266A (ja) * | 2000-04-06 | 2001-12-21 | Fujitsu Ltd | 光ピックアップ及び光記憶装置 |
US7304920B2 (en) * | 2000-06-26 | 2007-12-04 | Matsushita Electric Industrial Co., Ltd. | Optical head that detects tilt in an optical disk |
JP4505982B2 (ja) * | 2000-11-30 | 2010-07-21 | 三菱電機株式会社 | 光ヘッド装置、記録及び/又は再生装置並びに記録及び/又は再生方法 |
JP4242108B2 (ja) * | 2001-06-04 | 2009-03-18 | パナソニック株式会社 | 光ピックアップヘッドおよび情報記録再生装置 |
JP2003223738A (ja) * | 2001-11-22 | 2003-08-08 | Sony Corp | 光ピックアップ装置及び光ディスク装置並びに光学装置及び複合光学素子 |
JP4151313B2 (ja) * | 2002-06-03 | 2008-09-17 | 株式会社日立製作所 | 光再生装置 |
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 |
CN100520930C (zh) * | 2002-11-07 | 2009-07-29 | 松下电器产业株式会社 | 光头及具有光头的光盘装置 |
KR100965884B1 (ko) | 2004-01-14 | 2010-06-24 | 삼성전자주식회사 | 광픽업 |
JP2005216458A (ja) * | 2004-02-02 | 2005-08-11 | Sharp Corp | 光ピックアップ装置 |
TWI302307B (en) * | 2004-04-09 | 2008-10-21 | Hon Hai Prec Ind Co Ltd | Optical reading/writing system |
JP2005317118A (ja) * | 2004-04-28 | 2005-11-10 | Sankyo Seiki Mfg Co Ltd | 光ヘッド装置 |
JP4561706B2 (ja) * | 2005-11-16 | 2010-10-13 | 日本ビクター株式会社 | 光ピックアップ装置 |
JP4433315B2 (ja) * | 2006-01-12 | 2010-03-17 | ソニー株式会社 | 光ピックアップ及び光情報装置 |
-
2006
- 2006-04-24 CN CN2006800147813A patent/CN101171629B/zh active Active
- 2006-04-24 US US11/912,469 patent/US8107346B2/en active Active
- 2006-04-24 JP JP2007514720A patent/JP4954871B2/ja active Active
- 2006-04-24 CN CN201010131814.0A patent/CN101794596B/zh active Active
- 2006-04-24 WO PCT/JP2006/308573 patent/WO2006118082A1/ja active Application Filing
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH041933A (ja) * | 1990-04-18 | 1992-01-07 | Matsushita Electric Ind Co Ltd | 光学ヘッド |
JPH04119531A (ja) * | 1990-09-10 | 1992-04-21 | Mitsubishi Electric Corp | 光ピックアップ装置 |
JPH0547016A (ja) * | 1991-08-13 | 1993-02-26 | Asahi Optical Co Ltd | 光デイスク装置の信号検出系 |
JPH08306057A (ja) * | 1995-05-11 | 1996-11-22 | Matsushita Electric Ind Co Ltd | 光学ヘッド |
JPH1173658A (ja) * | 1997-06-30 | 1999-03-16 | Matsushita Electric Ind Co Ltd | 光学ヘッド及び、情報記録・再生装置 |
JPH11353670A (ja) * | 1998-06-10 | 1999-12-24 | Fujitsu Ltd | 光学装置,トラッキング装置,及び光ディスク装置 |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1942500B1 (en) * | 2007-01-08 | 2010-06-30 | Samsung Electronics Co., Ltd. | Optical pickup including unit to remove crosstalk in multi-layered disk, and optical recording and/or reproducing apparatus including the optical pickup |
JP2008198336A (ja) * | 2007-01-18 | 2008-08-28 | Matsushita Electric Ind Co Ltd | 光学ヘッド、光ディスク装置、コンピュータ、光ディスクプレーヤおよび光ディスクレコーダ |
JP2008262642A (ja) * | 2007-04-13 | 2008-10-30 | Victor Co Of Japan Ltd | 光ピックアップ装置 |
US8223613B2 (en) | 2008-01-21 | 2012-07-17 | Hitachi Media Electronics Co., Ltd. | Optical pickup device and optical disc apparatus |
US8547815B2 (en) | 2008-01-21 | 2013-10-01 | Hitachi Media Electronics Co., Ltd. | Optical pickup device and optical disc apparatus |
US7983134B2 (en) * | 2008-02-21 | 2011-07-19 | Lg Electronics Inc. | Method and apparatus for recording/reproducing data on/from a recording medium |
JP2010097663A (ja) * | 2008-10-17 | 2010-04-30 | Sharp Corp | 光ピックアップ装置 |
EP2202732A1 (en) * | 2008-12-23 | 2010-06-30 | Thomson Licensing | Apparatus and method for reading and apparatus for reading and writing holograms |
EP2202735A1 (en) | 2008-12-23 | 2010-06-30 | Thomson Licensing | Apparatus and method for reading and apparatus for reading and writing holograms |
Also Published As
Publication number | Publication date |
---|---|
US8107346B2 (en) | 2012-01-31 |
CN101171629B (zh) | 2010-10-06 |
US20090028035A1 (en) | 2009-01-29 |
JP4954871B2 (ja) | 2012-06-20 |
CN101171629A (zh) | 2008-04-30 |
JPWO2006118082A1 (ja) | 2008-12-18 |
CN101794596A (zh) | 2010-08-04 |
CN101794596B (zh) | 2013-08-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4954871B2 (ja) | 光ヘッド装置および光情報処理装置 | |
US7558162B2 (en) | Optical pick-up head, optical information apparatus, and optical information reproducing method | |
JP5149235B2 (ja) | 光ピックアップ装置 | |
JP2002025091A (ja) | 回折格子、光ピックアップ、誤差信号検出装置および誤差信号検出方法 | |
JP4533349B2 (ja) | 光ピックアップ装置 | |
KR100877458B1 (ko) | 광 픽업 헤드 장치와, 광 기억 매체 재생 장치 및 방법 | |
JP4751444B2 (ja) | 光ディスク装置 | |
JP2007059031A (ja) | 光ピックアップ | |
JP2007272980A (ja) | 光ピックアップ装置 | |
JP4806661B2 (ja) | 光ピックアップ及び光学的情報再生装置 | |
JP5318033B2 (ja) | 光ピックアップ装置 | |
JP5099014B2 (ja) | 光ヘッド装置および光学式情報記録再生装置 | |
KR20070052222A (ko) | 광학 픽업, 광기록재생장치 및 트래킹 에러 신호 검출 방법 | |
WO2010131461A1 (ja) | 光ヘッド装置、受光素子、集積回路、光集積素子、光ディスク装置および信号検出方法 | |
WO2010131406A1 (ja) | 光ヘッド装置、ホログラム素子、光集積素子、光情報処理装置および信号検出方法 | |
JP5474165B2 (ja) | 光ピックアップ及び光情報記録再生装置 | |
JP4765570B2 (ja) | 光学ピックアップ、光記録再生装置及びトラッキングエラー信号検出方法 | |
JP4770915B2 (ja) | 光ピックアップヘッド装置及び光情報装置 | |
JP2005100550A (ja) | 光ピックアップ及び光ディスク記録再生装置 | |
JP2007287235A (ja) | 光学式情報記録再生装置 | |
JP2012133852A (ja) | 光ピックアップ | |
JP2010020812A (ja) | 光ピックアップ装置及び光ディスク装置 | |
JP2008135123A (ja) | 光ピックアップ装置 | |
JP2008210461A (ja) | 光ピックアップ装置 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 200680014781.3 Country of ref document: CN |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2007514720 Country of ref document: JP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 11912469 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
NENP | Non-entry into the national phase |
Ref country code: RU |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 06732283 Country of ref document: EP Kind code of ref document: A1 |