WO2008075478A1 - 光ピックアップ装置 - Google Patents
光ピックアップ装置 Download PDFInfo
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- WO2008075478A1 WO2008075478A1 PCT/JP2007/064143 JP2007064143W WO2008075478A1 WO 2008075478 A1 WO2008075478 A1 WO 2008075478A1 JP 2007064143 W JP2007064143 W JP 2007064143W WO 2008075478 A1 WO2008075478 A1 WO 2008075478A1
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- light source
- pickup device
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0901—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following only
- G11B7/0903—Multi-beam tracking systems
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—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
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
- G11B7/127—Lasers; Multiple laser arrays
Definitions
- the present invention relates to an optical pickup device for use in an optical information processing apparatus that performs processing such as recording information on an optical information recording medium and reproducing or erasing information recorded on the optical information recording medium.
- optical disc such as a CD (Compact Disc) and a DVD (Digital Versatile Disc) uses an optical beam emitted from a light source such as a semiconductor laser device as an objective lens.
- the light is condensed on the recording track of the optical disc using the light source, and the reflected light from the optical disc is converted into an electrical signal by the light detector.
- the focus error signal and the tracking error signal are detected in order to accurately irradiate the desired recording track with the optical disk that rotates at high speed, and the objective lens is adjusted according to the surface deviation and eccentricity of the optical disk. Perform position control of
- a differential push pull (DPP) method is known as a typical detection method of tracking error signals.
- DPP differential push pull
- a light beam is split into three beams of a main beam, + first-order diffracted light, and first-order diffracted light, and the divided beams are provided on an optical disk so as to be adjacent to each other at a predetermined pitch. Focus on one guide groove.
- the phases of the push-pull signals obtained by detecting and calculating the reflected light of each beam are 180 degrees out of phase with each other between the main beam and the + first-order diffracted light and the first-order diffracted light.
- the pitch of the inner groove is different depending on the standard of the optical disc.
- the pitch of the guide grooves of the write-once type DVD-R (Recordable) and the rewritable type DVD-RW (Rewritable) is 0.74 m.
- the guide groove pitch of a DVD-RAM (Random Access Memory) or the like is 1.23 ⁇ m.
- the optical pickup device disclosed in Patent Document 2 is divided into a special diffraction grating force S3 for splitting a light beam, and the phase of the grating grooves periodically provided in each region is sequentially 90 degrees Let me shift by one.
- a tracking error detection method called an in-line DPP method using such a special diffraction grating stable tracking error detection can be performed on a plurality of optical information recording media having different guide groove pitches.
- Patent Document 1 Japanese Patent Publication No. 4-34212
- Patent Document 2 Japanese Patent Application Laid-Open No. 2004-145915
- FIG. 11 shows a focused spot obtained by focusing a light beam on an optical information recording medium by a conventional optical pickup device.
- the intensity of the focused spot 101 corresponding to the + first-order diffracted light becomes larger on the right side with respect to the radial direction X of the optical information recording medium, and becomes smaller on the left side.
- the light-condensing spot 102 corresponding to the ⁇ first-order diffracted light becomes smaller in intensity on the right side and becomes stronger on the left side.
- the special diffraction grating used in the conventional in-line DPP method is such that the phase of the grating groove 119a in the region 119 leads by 90 degrees with respect to the grating groove 120a in the central region 120.
- the phase of the grating groove 121a in the region 121 is delayed by 90 degrees. Therefore, the phase of the first-order diffracted light transmitted through the area 119 advances by 90 degrees with respect to the phase of the first-order diffracted light transmitted through the central region 120, and the phase of the first-order diffracted light transmitted through the area 121 is 90 degrees I'll be late.
- the relationship between the phase of the grating groove and the phase of the diffracted light is reversed. That is, with respect to the phase of the first-order diffracted light transmitted through central region 120, The phase of the first-order diffracted light transmitted through the area 119 is delayed by 90 degrees, and the phase of the first-order diffracted light transmitted through the area 121 is advanced by 90 degrees.
- the intensity distribution of the first-order diffracted light on the side 121 of the phase-delayed region 121 is greater than that of the focused spot 101 corresponding to the first-order diffracted light on the optical information recording medium.
- the strength is reduced.
- the intensity distribution of the first-order diffracted light is curved toward the region 119 where the phase is delayed, so that the intensity of the focused spot 102 corresponding to the first-order diffracted light becomes smaller at the right and the intensity at the left becomes larger.
- the intensity distribution of the focused spots in the focused spot 101 corresponding to the + first-order diffracted light and the focused spot 102 corresponding to the first-order diffracted light becomes asymmetrical, it corresponds to the main beam.
- the phase force S 180 degrees between the push-pull signal that detects the reflected light from the focused spot 100 and the push-pull signal that detects the reflected light from the focused spot 101 and the focused spot 102 also deviates. For this reason, it is not possible to form each focused spot on the same guide groove, and it becomes impossible to perform stable tracking error signal detection by the in-line DPP method.
- the present invention solves the above-mentioned conventional problems, and while maintaining the advantages of the in-line DPP method, an optical pickup device that performs stable tracking error detection on a plurality of optical information recording media having different guide groove pitches.
- the goal is to make it possible to
- the present invention comprises an optical pickup device having a diffraction grating which is divided into three regions which are out of phase with each other and a plurality of subblocks whose central regions are out of phase with each other.
- the first optical pickup apparatus is an optical pickup apparatus for recording information on an optical information recording medium and reading out and erasing information recorded on the optical information recording medium.
- a light source a diffraction grating that splits the emitted light beam emitted into the light source into at least three light beams, and a light detector that receives the light reflected by the light information recording medium.
- the diffraction grating is a first straight line having a periodic structure whose phases are different from each other by a dividing line in a first direction which is a straight line extending in a direction parallel to the tangential direction of the track of the optical information recording medium.
- Area, second area and third area A second direction which is divided into zones, the second zone being arranged between the first zone and the third zone and being a straight line extending parallel to the radius method of the optical information recording medium
- the phase of the periodic structure is divided into a first sub-block and a second sub-block different from each other by the dividing line of the periodic structure, and the phase of the periodic structure in the first sub-block is the period of the second sub-block.
- the phase of the periodic structure in the first region differs from the phase of the structure by approximately 180 degrees, and the phase of the periodic structure in the first region differs by approximately 90 degrees from the phase of the periodic structure in the first subblock. It is characterized in that it differs from the phase of the periodic structure in the region of approximately 180 degrees.
- the phase of the periodic structure in the first sub block differs from the phase of the periodic structure in the second sub block by about 180 degrees, and the phase of the periodic structure in the first region is The phase of the periodic structure in the first region differs by approximately 90 degrees from the phase of the periodic structure in the first sub-block, and the phase of the periodic structure in the first region differs by approximately 180 degrees from the phase of the periodic structure in the third region.
- phase of the + first-order diffracted light transmitted through the first region advances with respect to the phase of the + first-order diffracted light transmitted through the first sub-block
- the + first-order diffracted light transmitted through the second sub-block Delay for the phase of The phase of the + first-order diffracted light transmitted through the third region advances with respect to the phase of the + first-order diffracted light transmitted through the second sub-block, and the phase of the + first-order diffracted light transmitted through the third sub-block I'll be late.
- the first-order diffracted light it is reversed.
- the center of the light beam emitted from the light source may be disposed on the dividing line in the second direction in the second region of the diffraction grating.
- the light source is plural and the center of the light beam emitted from at least one of the light sources is a parting line in the second direction in the second region of the diffraction grating. It is placed in,,,.
- the light source includes a first light source and a second light source, and a center of the emitted light beam which is also emitted the first light source power is in a first region of the diffraction grating or One The center of the emitted light beam emitted from the second light source and disposed on the dividing line in the first direction that divides the area and the second area is within the third area of the diffraction grating or the second area.
- the first light source power is disposed on the dividing line in the first direction that divides the light source and the third region, and the center of the first light source power emitted and the second light source power of the second light source power are
- the connecting straight line is arranged to intersect with the dividing line in the second direction.
- the tangential length of the first sub-block and the tangential length of the second sub-block are preferably equal to each other. With such a configuration, the left-right symmetry of the focused spot of the sub beam can be surely improved.
- the at least three light beams may include zero-order diffracted light, + first-order diffracted light and first-order diffracted light.
- a plurality of guide grooves are periodically arranged on the recording surface of the optical information recording medium, and each light beam is one of the plurality of guide grooves. Focus on light.
- the first optical pickup device may further include an arithmetic processing circuit that detects a tracking error signal by a differential push-pull method based on an output signal from the light detector.
- the photodetector has at least three light receiving elements corresponding to each of the reflected lights, and each light receiving element is divided into a plurality of light receiving areas. It is also good.
- a second optical pickup device is directed to an optical pickup device for recording information on an optical information recording medium and reading out and erasing information recorded on the optical information recording medium.
- a diffraction grating that splits the emitted light beam emitted into a light beam into at least three light beams, and the respective light beams are collected to be independent collected spots on the recording surface of the optical information recording medium.
- an optical detector for receiving light reflected by the optical information recording medium, each of the light beams emitted as each focusing spot being received, and the diffraction grating is provided on the track of the optical information recording medium.
- the division lines in the first direction which are straight lines extending in a direction parallel to the tangential direction, allow the respective phases to be opposite each other.
- the first region, the second region and the third region having different periodic structures are divided, and the second region is disposed between the first region and the third region, and
- the dividing line in the second direction which is a straight line extending in parallel with the radial direction of the information recording medium, divides the phase of the periodic structure into a first sub-block and a second sub-block different in phase from each other, and
- the sub-blocks and the second sub-block are alternately arranged in a direction parallel to the tangential direction of the track of the optical information recording medium in the second area, and the period in the first sub-block is
- the phase of the structure differs by approximately 180 degrees from the phase of the periodic structure in the second subblock
- the phase of the periodic structure in the first region differs by approximately 90 degrees from the phase of the periodic structure in the first subblock.
- the phase of the periodic structure in the region of 1 is Wherein the different phase substantially 180 degrees in our Keru periodic structure in the region.
- the first sub-block and the second sub-block are in a direction parallel to the tangential direction of the track of the optical information recording medium in the second area.
- the phase forces of the periodic structure in the first subblock are alternately arranged, and differ by approximately 180 degrees from the phase of the periodic structure in the second subblock. Therefore, it is possible to suppress the difference between the area of the light beam passing through the first sub-block 13 and the area of the light beam passing through the second sub-block, that is, the difference in the amount of light passing through each. Therefore, good characteristics can be obtained regardless of the position of the diffraction grating in the Y direction, that is, the position of the center of the light beam emitted.
- the center of the light beam emitted from the light source may be disposed in a second region of the diffraction grating.
- a plurality of light sources may be provided, and a center of the emitted light beam from which at least one of the light sources is also emitted may be disposed in a second region of the diffraction grating. .
- the light source includes a first light source and a second light source, and a center of the light beam emitted from the first light source is within a first region of the diffraction grating or the first And the center of the light beam emitted from the second light source is located in the third region or in the second region and the third region of the diffraction grating. And may be disposed on a dividing line in a first direction to divide
- the at least three light beams may include zero-order diffracted light, + first-order diffracted light and first-order diffracted light.
- a plurality of guide grooves are periodically arranged on the recording surface of the optical information recording medium, and each light beam is formed by one of the plurality of guide grooves. Focus on light.
- the second optical pickup device may further include an arithmetic processing circuit that detects a tracking error signal by a differential push-pull method based on an output signal from the light detector.
- the photodetector has at least three light receiving elements corresponding to each of the reflected lights, and each light receiving element is divided into a plurality of light receiving areas. It is also good.
- optical pickup device of the present invention stable tracking error detection is performed on a plurality of optical information recording media having different guide groove pitches while maintaining the advantages of the in-line DPP method.
- a pickup device can be realized.
- FIG. 1 is a block diagram showing an optical pickup device according to a first embodiment of the present invention.
- FIG. 2 is a circuit diagram showing a photodetector of the optical pickup device according to the first embodiment of the present invention.
- FIG. 3 is a plan view showing a diffraction grating of the optical pickup device according to the first embodiment of the present invention.
- FIG. 4 is a plan view showing the shape of a focused spot formed on the recording surface of the optical information recording medium by the optical pickup device according to the first embodiment of the present invention.
- FIG. 5 is a graph showing the waveform of a signal obtained by the optical pickup device according to the first embodiment of the present invention.
- FIG. 6 is a plan view showing an example of the positional relationship between the diffraction grating of the optical pickup device according to the first embodiment of the present invention and the center of the light beam.
- FIG. 7 Among the diffraction grating and light beam of the optical pickup device according to the first embodiment of the present invention It is a top view which shows an example of the positional relationship with the heart.
- FIG. 8 is a plan view showing a diffraction grating of an optical pickup device according to a second embodiment of the present invention.
- FIG. 9 A plan view showing an example of the positional relationship between the diffraction grating of the optical pickup device according to the second embodiment of the present invention and the center of the light beam.
- FIG. 10 is a plan view showing an example of the positional relationship between the diffraction grating of the optical pickup device according to the second embodiment of the present invention and the center of the light beam.
- FIG. 11 A plan view showing the shape of a focused spot formed on the recording surface of the optical information recording medium by the optical pickup device according to the conventional example.
- FIG. 12 is a plan view showing a diffraction grating of an optical pickup device according to a conventional example.
- FIG. 1 shows a schematic configuration of the optical pickup device according to the first embodiment.
- a light source 11 such as a semiconductor laser element that emits an emitted light beam 31, a main beam that is at least zero-order diffracted light of the emitted light beam 31, + 1
- the diffraction grating 12 diffracts and branches into three light beams of the sub-beam which is the second-order diffracted light and the sub-beam (which is not shown) of the first-order diffracted light, and the half light which guides the branched light beam to the optical information recording medium 51
- the mirror 15 and an integrated circuit board 17 equipped with a photodetector 16 for receiving the reflected light of the branched light beam reflected by the optical information recording medium 51 are provided. Thereby, the recording of the information on the optical information recording medium 51 and the reading of the information recorded on the optical information recording medium 51 are performed.
- a collimating lens 18 and an objective lens 19 are provided between the half mirror 15 and the optical information recording medium 51.
- An outgoing light beam 31 emitted from a light source 11 is diffracted and branched into three light beams of at least 0th-order light, + first-order diffracted light and first-order diffracted light by a diffraction grating 12 and then reflected by a half mirror 15 , Then pass through collimating lens 18 Object lens 19 is reached.
- the zeroth-order light, the + first-order diffracted light and the first-order diffracted light which are diffracted and branched by the diffraction grating 12 are respectively collected by the objective lens 19 independently on the recording surface of the optical information recording medium 51 and three focused spots.
- FIG. 2 shows a circuit configuration of an integrated circuit board 17 on which the photodetector 16 in the optical pickup device shown in FIG. 1 is mounted.
- the integrated circuit substrate 17 has a light receiving element 21A, a light receiving element 21B and a light receiving element 21C, and an arithmetic processing circuit 23 for calculating a signal from the light receiving element.
- the main beam 31a and the two sub beams 31b and 31c branched from the outgoing light beam 31 by the diffraction grating 12 are received by the light receiving element 21A, the light receiving element 21B and the light receiving element 21C, respectively.
- the light receiving element 21A, the light receiving element 21B, and the light receiving element 21C are each divided into a plurality of light receiving areas.
- Signals detected by the light receiving element 21 A, the light receiving element 21 B, and the light receiving element 21 C are input to the arithmetic processing circuit 23.
- the arithmetic processing circuit 23 receives the light receiving element 21A, the light receiving element 21B, and the light receiving element 21C, and the subtractor 24, the subtracter 25, the subtracter 26, and the subtracter 24, the subtracter 25, and the subtracter 26 receive And an amplifier 28 and a subtractor 29.
- the subtractor 24, the subtracter 25 and the subtracter 26 respectively receive the signals from the light receiving element 21A, the light receiving element 21B and the light receiving element 21C, and output push-pull signals MPP, SPP1 and SPP2.
- the adder 27, the amplifier 28, and the subtracter 29 will be described later.
- FIG. 2 shows a circuit configuration where each light receiving element is divided into two light receiving areas, each light receiving element may be divided into three or more light receiving areas.
- shape of each beam in each light receiving element is represented to circular shape typically, a beam shape is not limited to this.
- the optical pickup device of the present embodiment is characterized by the diffraction grating 12 that diffracts the outgoing light beam 31, particularly its periodic structure.
- FIG. 3 shows the periodic structure or grating pattern of the diffraction grating 12.
- the grating surface of the diffraction grating 12 is a direction in which the guide grooves of the optical information recording medium 51 extend (hereinafter referred to as the Y direction), that is, the tangential direction of the track of the optical information recording medium 51
- the first region 12A, the second region 12A, and the division lines D1 and D2 extend in substantially parallel directions. It is divided into three areas of area 12B and third area 12C. That is, the first area 12A and the second area 12B are adjacent to each other with the dividing line D1 interposed therebetween, and the second area 12B and the third area 12C are adjacent to each other with the dividing line D2 interposed therebetween. .
- the second region 12 B is formed of a first sub-block 13 and a first sub-block 13 by a dividing line D 3 extending in a direction substantially parallel to the radial direction of the optical information recording medium 51 (hereinafter referred to as X direction). It is divided into two sub-blocks 14. It is preferable that the length of the first sub-block 13 in the Y direction and the length of the second sub-block in the ⁇ direction be equal to each other.
- the parallel direction means a parallel direction in consideration of an optical system provided between the diffraction grating and the optical information recording medium.
- grating grooves 12a are periodically provided in the first region 12A, the second region 12B, and the third region 12C along the X direction. Also, the periods of the grating grooves 12a are different from each other in the first region 12A, the second region 12B and the third region 12C, and also between the first sub block 13 and the second sub block 14 They are different from each other.
- the phase of the periodic structure formed by the grating grooves 12a formed in the first region 12A is the period formed in the first subblock 13 of the second region 12B. (deviates + 90 °.) substantially is advanced 90 degrees with respect to the structure of the phase 0 that is, the arrangement period of the grating grooves 12a in the first region 12A, the lattice in the first sub-block 13 groove 12a It is shifted in the + Y direction by 1/4 cycle based on the placement cycle of.
- the phase of the periodic structure formed in the third region 12C is formed in the first sub-block 13, and is delayed by substantially 90 degrees with respect to the phase of the periodic structure (-90 degrees Out of alignment. ).
- the arrangement period of the grating grooves 12a in the third region 12C is shifted in the Y direction by a quarter of a period based on the arrangement period of the grating grooves 12a in the first sub-block 13. Therefore, the phase of the periodic structure of the first region 12A and the phase of the periodic structure of the third region 12C are substantially different by 180 degrees. Also, the phase of the periodic structure of the second sub-block 14 is substantially 180 degrees out of phase with the phase of the periodic structure of the first sub-block 13. That is, the arrangement period of the grating grooves 12a in the second sub-block 14 is a half of the arrangement period of the grating grooves 12a in the first sub-block 13 in the + Y direction. It is done.
- the phase shift of the periodic structure in each region does not have to be exactly 90 degrees or 180 degrees. If the focused spot on the recording surface of the optical information recording medium 51 has a shape as will be described later, it may include an error of about 10 degrees.
- the center (emission point center) L1 of the light beam 31 emitted from the light source 11 is preferably disposed on the dividing line D3 within the range of the assembly accuracy of the apparatus, as shown in FIG.
- the outgoing light beam 31 incident on the diffraction grating 12 is branched into sub beams having a predetermined phase difference due to the periodic structures respectively formed in the first area 12A, the second area 12B and the third area 12C. And is led to the optical information recording medium 51.
- FIG. 4 shows the shapes of the main beam 31a and the two sub-beams 31b and 31c of the light beam generated by the diffraction grating 12 on the recording surface of the optical information recording medium 51. Also in FIG. 4, the X direction indicates the radial direction of the optical information recording medium, and the Y direction indicates the direction in which the guide groove extends.
- the first subblock 13 and the second subblock 14 in the second region 12B of the diffraction grating 12 have a phase difference of 180 degrees between the diffraction gratings. Therefore, the diffracted light transmitted through the first subblock 13 and the diffracted light transmitted through the second subblock 14 cancel each other, and the optical information recording medium 51 of the sub beam 31 b and the sub beam 31 c shown in FIG. 4 is recorded.
- the light collecting spot on the surface has a smaller intensity at the center.
- the phase shift between the first subblock 13 and the second subblock 14 is ⁇ 10 with respect to 180 degrees, if the intensity at the central portion of the focused spot of the subbeams 31b and 31c can be reduced. There is no problem even if it contains a degree of error.
- phase of the diffraction grating in the first region 12A leads by 90 degrees with respect to the first subblock 13 in the second region 12B, and is delayed by 90 degrees with respect to the second subblock 14. ing.
- phase of the diffraction grating in the third region 12 C leads by 90 degrees with respect to the second sub-block 14 and lags by 90 degrees with respect to the first sub-block 13. Therefore, the phase of the first-order diffracted light transmitted through the first region 12A is the phase of the first-order diffracted light transmitted through the first sub-block 13. Then, it is advanced by 90 degrees and delayed by 90 degrees with respect to the phase of + first-order diffracted light transmitted through the second subblock 14.
- the phase of the + first-order diffracted light transmitted through the third region 12 C is advanced by 90 degrees with respect to the phase of the + first-order diffracted light transmitted through the second subblock 14 and transmitted through the first subblock 13 + 90 degrees behind the phase of the first-order diffracted light.
- the opposite phenomenon occurs for the first-order diffracted light. Therefore, since the light with the phase advanced by 90 degrees and the light with the phase delayed by 90 degrees exist equally on the left and right sides of the focus spot in the Y direction, the intensity distribution of the focus spot is in the Y direction. Is symmetrical about the axis. Also in this case, the phase shift between the first area 12A and the second area 12B and the phase shift between the second area 12B and the third area 12C are each 10 degrees with respect to 90 degrees. Even the problem, including the error of.
- a plurality of guide grooves 51a are periodically arranged. Further, as shown in FIG. 4, focused spots where the main beam 31a, sub beam 3 lb and sub beam 3 lc of the light beam are focused by the objective lens 19 are arranged in the same guide groove 51a.
- the main beam 3 la, the sub beam 3 lb and the sub beam 31 c are reflected at each focused spot, and the reflected light corresponding to each focused spot is received by the light receiving element 21 A provided in the light detector 16. , And are received by the light receiving element 21B and the light receiving element 21C.
- the light receiving element 21A, the light receiving element 21B and the light receiving element 21C output the push signal MPP corresponding to the main beam 31a, the push pull signal SPP1 corresponding to the sub beam 3 lb, and the push pull signal SPP2 corresponding to the sub beam 31c.
- the radial shift of the objective lens 19 (radial shift of the optical information recording medium) and the offset component of MPP, SPP1 and SPP2 caused by the tilt of the optical information recording medium 51
- the tilt of the information recording medium 51 occurs on the same side (in phase). Therefore, the operation push pull (DPP) signal in which the offset due to the radial shift of the objective lens 19 and the tilt of the optical information recording medium 51 is canceled is obtained using the adder 27, amplifier 28 and subtractor 29 shown in FIG. This can be detected by performing arithmetic processing as shown in equation (1).
- DPP operation push pull
- FIG. 5 shows an output waveform of the DPP signal obtained based on the push-pull signal MPP, the push-pull signal SPP1, the push-pull signal SPP2, and the equation (1).
- the vertical axis represents the signal intensity
- the horizontal axis represents the relative position of the focused spot on the optical information recording medium 51.
- the phases of SPP1 and SPP2 are exactly 180 degrees out of phase with the phase of MPP.
- the DPP signal obtained based on the equation (1) has an appropriate value, it is possible to form each condensing spot on the same guide groove.
- the coefficient k of (Expression 1) is to correct the difference in light intensity between the main beam 31a, the sub beam 31b and the sub beam 31c reflected from the optical information recording medium 51.
- the coefficient k may be aZ2 b. That is, the coefficient k is a constant determined according to the optical information recording medium 51.
- the signal processing circuit may use a conventional configuration.
- the center of the light beam L 1 emitted from the first light source and the center of the light beam L 2 emitted from the second light source among the plurality of light sources are shown.
- the connecting straight line may be arranged to intersect the dividing line D3 in the second region 12B.
- the position of the center L3 of the light beam emitted from the third light source is not particularly limited. Also, the third light source may not be present.
- FIG. 8 shows a diffraction grating 12 used in the optical pickup device according to the second embodiment.
- the same components as in FIG. 3 will be assigned the same reference numerals and descriptions thereof will be omitted.
- the diffraction grating 12 of this embodiment includes a first subblock 13 and a second subblock 13 in a second region 12B.
- the sub blocks 14 are alternately provided repeatedly.
- the difference between the area of the outgoing light beam 31 passing through the first subblock 13 and the area of the outgoing light beam 31 passing through the second subblock 14, ie, It is possible to suppress the difference in the amount of light passing through it. Accordingly, good characteristics can be obtained regardless of the position of the diffraction grating 12 in the Y direction, ie, the position of the center of the light beam emitted from the light source 11.
- first sub block 13 and the second sub block 14 are repeated three times is not particularly limited. Also, the order of repetition may be reversed.
- the lengths in the Y direction of the first sub-block 13 and the second sub-block 14 may be equal to each other. However, it is preferable that the sum of the lengths in the Y direction of the first sub-block 13 be equal to the sum of the lengths in the Y direction of the second sub-block 14.
- FIG. 8 shows an example in which the center L 1 of the outgoing light beam 31 emitted from the light source 11 is disposed on the dividing line of the first sub-block 13 and the second sub-block 14. .
- the center of the emitted light beam 31 emitted from the light source 11 which is not limited to this is disposed in the second region 12B!,!
- the second embodiment shows the case of one light source, a plurality of light sources may be present.
- the center of the light beam emitted from at least one light source is preferably disposed in the second region 12B.
- the center L 1 of the light beam emitted from the first light source among the plurality of light sources is disposed in the first region 12 A, and emitted from the second light source
- the center L2 of the light beam may be located in the third region 12C.
- the position of the center L3 of the light beam emitted from the third light source is not particularly limited. Also, the third light source may not be present.
- the optical information recording medium 51 is not particularly limited. DVD-ROM DVD-RAM DVD-RAM including DVD-R, DVD-RW, etc. and CD-ROM, CD- CDs including R, CD-RW, etc. can be used. Further, the wavelength of the outgoing light beam 31 may be determined according to the optical information recording medium 51, and in the case of DVD and CD, it may be about 780 nm with about 650 nm power. Also, for DVDs, guide grooves for DVD-R etc. It is possible to perform stable tracking error signal detection regardless of whether the pitch is 0.74 / zm or the guide groove pitch such as DVD-RAM is 1.23 / zm.
- an optical system in which a light source and a light detector are arranged is used, and between the light source and the collimating lens You may arrange the diffraction grating ⁇
- the grating grooves provided in the respective regions of the diffraction grating 12 are formed along the X direction which is the radial direction of the optical information recording medium, but instead, grating grooves are formed. It may be provided obliquely to the X direction.
- the optical pickup device makes it possible to cope with various optical information recording media having different guide groove pitches, and realizes more stable recording and reproduction. Tracking error signal detection is achieved. That is, the optical pickup device according to each embodiment can realize miniaturization, simplification, low cost, high efficiency, etc. in the recording device and reproducing device of the DVD system and the CD system. .
- an optical information processing apparatus that performs processing such as recording, reproduction, and deletion of information on an optical information recording medium such as an optical disc, a reproduction signal, recording signal, and the like used for an optical head device that is a main component thereof.
- the optical pickup device is very useful as an optical pickup device having a function of detecting various servo signals and the like.
- the optical pickup device of the present invention is an optical pickup device that performs stable tracking error detection for a plurality of optical information recording media having different pitches of the inner groove while maintaining the advantages of the in-line DPP method.
- the present invention is useful as an optical pickup device or the like for use in an optical information processing apparatus which can realize information recording on an optical information recording medium and reproduction or deletion of information recorded on the optical information recording medium.
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- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Recording Or Reproduction (AREA)
- Optical Head (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/090,385 US7978586B2 (en) | 2006-12-18 | 2007-07-18 | Optical pickup device |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2006-339532 | 2006-12-18 | ||
JP2006339532A JP4444947B2 (ja) | 2006-12-18 | 2006-12-18 | 光ピックアップ装置 |
Publications (1)
Publication Number | Publication Date |
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WO2008075478A1 true WO2008075478A1 (ja) | 2008-06-26 |
Family
ID=39536114
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2007/064143 WO2008075478A1 (ja) | 2006-12-18 | 2007-07-18 | 光ピックアップ装置 |
Country Status (6)
Country | Link |
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US (1) | US7978586B2 (ja) |
JP (1) | JP4444947B2 (ja) |
KR (1) | KR20090092692A (ja) |
CN (1) | CN101356579A (ja) |
TW (1) | TW200828290A (ja) |
WO (1) | WO2008075478A1 (ja) |
Families Citing this family (1)
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JP4444977B2 (ja) | 2007-02-01 | 2010-03-31 | パナソニック株式会社 | 光ピックアップ装置 |
Citations (7)
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JP2004145915A (ja) * | 2002-10-22 | 2004-05-20 | Hitachi Ltd | 光ピックアップおよびそれを用いた光学的情報記録装置または再生装置 |
JP2005353187A (ja) * | 2004-06-11 | 2005-12-22 | Nec Corp | 光ヘッド装置及び光学式情報記録再生装置 |
JP2006228304A (ja) * | 2005-02-16 | 2006-08-31 | Sanyo Electric Co Ltd | トラッキング制御装置 |
JP2007035193A (ja) * | 2005-07-28 | 2007-02-08 | Sharp Corp | 光ピックアップ装置 |
JP2007042252A (ja) * | 2005-06-29 | 2007-02-15 | Enplas Corp | 光学素子および光ピックアップ装置ならびに光学的情報記録および/または再生装置 |
JP2007122779A (ja) * | 2005-10-25 | 2007-05-17 | Sony Corp | 光ピックアップ及び光ディスク装置 |
JP2007141425A (ja) * | 2005-10-17 | 2007-06-07 | Sanyo Electric Co Ltd | 光ピックアップ装置および光ディスク装置 |
Family Cites Families (3)
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JPS6194246A (ja) | 1984-10-15 | 1986-05-13 | Sony Corp | 光学式ヘッドのトラッキング誤差検出方法 |
JPH0434212A (ja) | 1990-05-31 | 1992-02-05 | Ntn Corp | 複列内向き円錐ころ軸受 |
WO2008023567A1 (fr) * | 2006-08-25 | 2008-02-28 | Panasonic Corporation | Dispositif à tête optique, élément de diffraction, dispositif d'informations optiques, ordinateur, lecteur de disque, système de navigation automobile, enregistreur à disque optique et véhicule |
-
2006
- 2006-12-18 JP JP2006339532A patent/JP4444947B2/ja not_active Expired - Fee Related
-
2007
- 2007-07-18 US US12/090,385 patent/US7978586B2/en not_active Expired - Fee Related
- 2007-07-18 WO PCT/JP2007/064143 patent/WO2008075478A1/ja active Application Filing
- 2007-07-18 KR KR1020087024117A patent/KR20090092692A/ko not_active Application Discontinuation
- 2007-07-18 CN CNA2007800011220A patent/CN101356579A/zh active Pending
- 2007-12-03 TW TW096145949A patent/TW200828290A/zh unknown
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004145915A (ja) * | 2002-10-22 | 2004-05-20 | Hitachi Ltd | 光ピックアップおよびそれを用いた光学的情報記録装置または再生装置 |
JP2005353187A (ja) * | 2004-06-11 | 2005-12-22 | Nec Corp | 光ヘッド装置及び光学式情報記録再生装置 |
JP2006228304A (ja) * | 2005-02-16 | 2006-08-31 | Sanyo Electric Co Ltd | トラッキング制御装置 |
JP2007042252A (ja) * | 2005-06-29 | 2007-02-15 | Enplas Corp | 光学素子および光ピックアップ装置ならびに光学的情報記録および/または再生装置 |
JP2007035193A (ja) * | 2005-07-28 | 2007-02-08 | Sharp Corp | 光ピックアップ装置 |
JP2007141425A (ja) * | 2005-10-17 | 2007-06-07 | Sanyo Electric Co Ltd | 光ピックアップ装置および光ディスク装置 |
JP2007122779A (ja) * | 2005-10-25 | 2007-05-17 | Sony Corp | 光ピックアップ及び光ディスク装置 |
Also Published As
Publication number | Publication date |
---|---|
TW200828290A (en) | 2008-07-01 |
US20100177618A1 (en) | 2010-07-15 |
JP2008152853A (ja) | 2008-07-03 |
KR20090092692A (ko) | 2009-09-01 |
US7978586B2 (en) | 2011-07-12 |
JP4444947B2 (ja) | 2010-03-31 |
CN101356579A (zh) | 2009-01-28 |
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