WO2007114006A1 - Optical pickup device - Google Patents

Optical pickup device Download PDF

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Publication number
WO2007114006A1
WO2007114006A1 PCT/JP2007/054987 JP2007054987W WO2007114006A1 WO 2007114006 A1 WO2007114006 A1 WO 2007114006A1 JP 2007054987 W JP2007054987 W JP 2007054987W WO 2007114006 A1 WO2007114006 A1 WO 2007114006A1
Authority
WO
WIPO (PCT)
Prior art keywords
semiconductor laser
light
pickup device
wavelength
optical pickup
Prior art date
Application number
PCT/JP2007/054987
Other languages
French (fr)
Japanese (ja)
Inventor
Masahiko Nishimoto
Naoki Nakanishi
Masayuki Ono
Yasuyuki Kochi
Original Assignee
Matsushita Electric Industrial Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co., Ltd. filed Critical Matsushita Electric Industrial Co., Ltd.
Publication of WO2007114006A1 publication Critical patent/WO2007114006A1/en

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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
    • G11B7/125—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
    • G11B7/1275—Two or more lasers having different wavelengths
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1353—Diffractive elements, e.g. holograms or gratings

Definitions

  • the present invention is used in an optical head device that is a key component in an optical information processing apparatus that performs processing such as information recording, reproduction, and erasing on an optical information recording medium such as an optical disc.
  • the present invention relates to an optical pickup device having a function of detecting reproduction and / or recording signals and various servo signals.
  • FIG. 14 is a detailed view of the integrated laser unit 1.
  • the integrated laser unit 1 will be described in detail below with reference to FIG.
  • the integrated laser unit 1 is configured by laminating a laser package 2, a transparent substrate 3, and a composite polarization beam splitter (composite PBS) 4 in this order on the substrate.
  • composite PBS composite polarization beam splitter
  • the laser package 2 includes a laser stage 7 on which a first semiconductor laser 5 that oscillates in the 650 nm band and a second semiconductor laser 6 that oscillates in the 780 nm band are mounted in close proximity, and a photodetector 8.
  • the detection table 9 is housed.
  • three beams for generating three beams for tracking control are formed at positions facing the first and second semiconductor lasers 5 and 6 on the surface of the transparent substrate 3 that is in close contact with the laser package 2.
  • a diffraction grating 10 is formed.
  • the first polarization hologram element 11 that diffracts the light beam of the first semiconductor laser 5 incident from the composite PBS 4 and guides it to the photodetector 8 is incident on the surface that is in close contact with the composite PBS 4 and the composite PBS 4.
  • a second polarization hologram element 12 that diffracts the optical beam of the second semiconductor laser 6 and guides it to the photodetector 8 is formed.
  • the composite PBS 4 has a polarization beam splitter surface 4a and a reflection surface 4b.
  • a wave plate 13 is laminated on the surface that is not in close contact with the transparent substrate 3.
  • the laser package 2, the transparent substrate 3, the composite PBS 4 and the wave plate 13 are integrally attached and fixed.
  • the light beam A emitted from the first semiconductor laser 5 in the 650 nm band includes a three-beam diffraction grating 10 and a second polarization hologram element as indicated by a solid line. 12
  • the light passes through the polarizing beam splitter surface 4a of the composite PBS 4 and the wave plate 13, and is guided to a collimator lens (not shown).
  • collimated light After collimated light is collimated by a collimator lens (not shown), the light is condensed on an optical information recording medium (not shown) by an objective lens (not shown).
  • the return light A ′ reflected by the optical information recording medium (not shown) is converted into an objective lens (not shown) and a collimator lens (not shown).
  • the light beam B emitted from the second semiconductor laser 6 in the 780 nm band is 3 by the diffraction grating 10 for three beams as indicated by a broken line.
  • the light passes through the second polarization hologram element 12, the polarization beam splitter surface 4a of the composite PBS 4, and the wave plate 13, and is guided to a collimator lens (not shown).
  • a collimator lens it is condensed on an optical information recording medium (not shown) by an objective lens (not shown).
  • the return light B ′ passes through an objective lens (not shown) and a collimator lens (not shown) and is guided to the integrated laser unit 1. And The light passes through the polarization beam splitter surface 4 a of the composite PBS 4, is diffracted by the second polarization hologram element 12, and is condensed on the light receiving element of the photodetector 8.
  • the first polarization hologram element 11 and the second polarization hologram element 12 are formed by engraving a diffraction grating on a special substrate, and 0 according to the polarization direction (p-polarization, s-polarization) of the transmitted light beam. It is an element that greatly varies the ratio of the secondary light and ⁇ primary light. That is, when the transmitted laser beam is p-polarized light, almost all of them are 0th order light, and ⁇ 1st order light is hardly generated. On the other hand, when the transmitted light beam is polarized, almost all of the light is ⁇ 1st order light, and almost no 0th order light is generated.
  • the wave plate 13 generates a phase difference that acts as a quarter wave plate for the wavelength from the first semiconductor laser 5 in the 650 m band, while the wave plate 13 from the second semiconductor laser 6 in the 780 nm band.
  • the thickness is set so as to generate a phase difference that acts as a 1Z4 wavelength plate for the other wavelengths.
  • Patent Document 1 Japanese Unexamined Patent Application Publication No. 2004-87089
  • the base material of the optical information recording medium is designed on the assumption that it does not have birefringence. If there is a large birefringence in the information recording medium, the large birefringence causes the light beam from the poor optical information recording medium to pass through the quarter-wave plate and not to be s-polarized, but to be p-polarized, Only the 0th order light is transmitted without being diffracted by the polarization hologram element. For this reason, in the conventional optical pickup device as shown in FIG. 14, light does not enter the photodetector, the information from the optical information recording medium cannot be read, and the focus error signal and tracking error signal cannot be controlled. There is a problem (first problem).
  • the conventional optical pickup device as shown in Fig. 14 uses two polarization hologram elements and further uses a composite PBS, so that the number of parts increases and the assembly becomes complicated. There is a (second issue).
  • the present invention takes into consideration such a problem (first problem) of the conventional optical pickup device described above, and can be applied to various optical information recording media having different wavelengths of semiconductor laser light to be used.
  • An object of the present invention is to provide an optical pickup device that can cope with the above and can detect a focus error signal and a tracking error signal more stably.
  • the present invention has been made in consideration of the above-described problem (second problem) of the conventional optical pickup device, and an object of the present invention is to provide an optical pickup device having a smaller number of parts than the conventional one. is there.
  • the first aspect of the present invention is a first semiconductor laser that emits a light beam having a first wavelength
  • a second semiconductor laser that emits a light beam having a second wavelength longer than that of the first semiconductor laser
  • a diffraction grating for diffracting the light beam of the first wavelength or the light beam of the second wavelength into diffracted lights of different orders
  • a collimator lens for converting the diffracted light diffracted by the diffraction grating into a parallel beam; an objective lens for condensing the parallel beam on a recording surface of the optical information recording medium; and reflecting by the recording surface of the optical information recording medium
  • a polarization hologram element that diffracts the reflected return light
  • An optical pickup device comprising: a wave plate in which regions having different phase-related characteristics are alternately arranged in a strip shape; and a plurality of light receiving elements that receive diffracted light diffracted by the polarization hologram element.
  • the diffraction grating is configured such that the light beam is divided into 0-order diffracted light and
  • the optical pickup device diffracts into first-order diffracted light.
  • the wave plate is a wave plate in which the regions having two different characteristics are alternately arranged in a strip shape
  • the phase difference of one of the two different characteristics is 1/4 + a
  • the phase difference of the other characteristic is The optical pickup device according to the first or second aspect of the present invention, wherein ⁇ 1/4 is ⁇ , and ⁇ is ⁇ 1/8 ⁇ ⁇ 1/8.
  • the wave plate has a strip shape in which the two regions having different characteristics are formed. Wave plates arranged alternately,
  • the phase difference of one of the two different characteristics is 1/4, and the phase difference of the other characteristic is 3 ⁇
  • the optical pickup device according to the first or second aspect of the present invention wherein ⁇ 1/4.
  • the fifth aspect of the present invention is the optical pickup device according to any one of the first to fourth aspects, wherein the wave plate is provided between the objective lens and the collimator lens.
  • the sixth invention is the optical pickup device according to any one of the first to fifth inventions, wherein the polarization hologram is provided between the diffraction grating and the collimator lens. .
  • the seventh aspect of the present invention is the optical pickup device according to any one of the first to sixth aspects of the present invention, wherein the wave plate and the polarization hologram element are configured in a body.
  • Equation 1 The polarization hologram element is arranged at a position of a distance L that satisfies a X j3 / (NA 2-0.67 XNA1) ⁇ L ⁇ f2,
  • the polarization hologram element is divided into four regions, and regions having two different diffraction characteristics are alternately arranged in a strip shape in each of the regions.
  • the optical pickup device according to any one of the first to eighth aspects of the present invention.
  • the optical axis of the first semiconductor laser and the center of the four regions of the polarization hologram element substantially coincide with the optical axis center of the collimator lens.
  • the light receiving element is separated from the first semiconductor laser and the second semiconductor laser on both sides of the first semiconductor laser and the second semiconductor laser. And arranged on an extension line connecting the light emission position in the first semiconductor laser and the light emission position in the second semiconductor laser,
  • the number of light receiving elements arranged on the opposite side of the second semiconductor laser with respect to the first semiconductor laser force is arranged on the opposite side of the first semiconductor laser with respect to the second semiconductor laser.
  • the optical pickup device according to any one of the first to tenth aspects, wherein the number is less than the number of the light receiving elements.
  • the light beam having the first wavelength or the light beam having the second wavelength reflected from the recording surface of the optical information recording medium is diffracted by the polarization hologram element.
  • the optical pickup device according to any one of the first to eleventh aspects, wherein the diffracted light is received by a common light receiving element.
  • the thirteenth aspect of the present invention is the optical pickup apparatus according to the twelfth aspect of the present invention, wherein a focus and tracking error signal is obtained based on a signal from the light receiving element.
  • a focus error signal is obtained by the light receiving element disposed on the opposite side of the second semiconductor laser as viewed from the first semiconductor laser, and the second semiconductor laser is obtained.
  • the first semiconductor laser, the second semiconductor laser, and the plurality of light receiving elements are mounted on the same integrated circuit substrate.
  • ⁇ The optical pickup device according to any one of 14 above.
  • two focus error signal current-voltage conversion amplifier circuits and six tracking error signal current-voltage conversion amplifier circuits are mounted on the integrated circuit board. This is the optical pickup apparatus of the fifteenth aspect of the present invention.
  • the 17th aspect of the present invention is the optical pickup apparatus according to the 15th or 16th aspect of the present invention, wherein the integrated circuit substrate and the diffraction grating are mounted in one package.
  • the eighteenth aspect of the present invention is the book according to any one of the first to seventeenth aspects, wherein the first semiconductor laser and the second semiconductor laser are formed of one monolithic semiconductor laser. It is an optical pickup device of the invention.
  • the diffraction grating includes a first diffraction region and a second diffraction region having different diffraction efficiencies
  • the diffraction efficiency of the 0th order diffracted light in the first diffraction region is larger than the diffraction efficiency of the 0th order diffracted light in the second diffraction region.
  • the first diffraction region and the second diffraction region are formed in a band shape
  • optical pickup according to any one of the first to 18th aspects, wherein the grating in the first diffraction region and Z or the grating in the second diffraction region are inclined with respect to the first diffraction region.
  • the 0th-order diffracted light generated in the first diffraction region is used as a main beam for recording or reproducing an information signal to or from the optical information recording medium.
  • the ⁇ 1st-order diffracted light generated in the second diffraction region is used as a sub beam.
  • the optical pickup apparatus according to the nineteenth aspect of the present invention according to the nineteenth aspect of the present invention.
  • the optical pickup device of the present invention it is possible to cope with various optical information recording media in which the wavelength of the semiconductor laser light to be used is different, and the focus error signal and the tracking error signal are more stable. The effect that it becomes possible to detect is demonstrated.
  • optical pickup device of the present invention it is possible to further reduce the number of parts.
  • FIG. L (a), (b): Schematic cross-sectional views showing the configuration of the main part of the optical system of the optical pickup device according to the first embodiment of the present invention.
  • FIG. 2 is a plan view showing the configuration of the polarization hologram element according to the first embodiment of the present invention.
  • FIG. 3 is a plan view showing the configuration of the wave plate according to the first embodiment of the present invention.
  • FIG. 4 is a plan view showing the configuration of the light receiving element according to the first embodiment of the present invention.
  • FIG. 5 is a schematic cross-sectional view showing the configuration of the main part of the optical system of the optical pickup device according to the second embodiment of the present invention.
  • FIG. 6 is a schematic cross-sectional view showing the configuration of the main part of the optical system of the optical pickup device according to the third embodiment of the present invention.
  • FIG. 7 is a plan view of a diffraction grating of an optical pickup device in Embodiment 4 of the present invention.
  • FIG. 8 is a plan view of another example of the diffraction grating of the optical pickup device in the fourth embodiment of the present invention.
  • FIG. 9 is an equivalent circuit diagram of the integrated circuit board of the optical pickup device in the fifth embodiment.
  • FIG. 12 (a) A diagram showing the transmittance of the s-polarized component in the wave plate 108 with respect to the change in the birefringence phase difference of the optical information recording medium when the wavelength of the light beam 105 is 1, (b) Diagram showing transmittance of s-polarized component at 2
  • FIG. 13 (a), (b): Schematic sectional views showing another configuration example of the main part of the optical system of the optical pickup device according to the first embodiment of the present invention.
  • FIG. 14 is a schematic diagram showing a conventional optical pickup device.
  • First optical information recording medium First wavelength light beam First semiconductor laser
  • Second optical information recording medium Second wavelength light beam Second semiconductor laser Diffraction grating
  • Polarization hologram element First light receiving element group Second light receiving element group Third light receiving element group Integrated circuit board
  • Monolithic two-wavelength semiconductor laser first diffraction region of diffraction grating second diffraction region of diffraction grating 501 to 508 Current-voltage conversion amplifier circuit
  • FIG. 1 schematically shows the configuration of the optical pickup device according to the first embodiment of the present invention.
  • FIG. 2 shows a polarization hologram element according to Embodiment 1 of the present invention.
  • FIG. 3 shows a wave plate according to Embodiment 1 of the present invention.
  • FIG. 4 is a plan view showing the configuration of the light receiving element according to Embodiment 1 of the present invention.
  • the optical pickup device shown in FIG. 1 includes a first semiconductor laser 103 that emits a light beam 102 having a first wavelength corresponding to recording and reproduction on the first optical information recording medium 101, and a second semiconductor laser 103.
  • a second semiconductor laser 106 that emits a light beam 105 having a second wavelength longer than that of the first semiconductor laser 103, corresponding to recording and reproduction of the optical information recording medium 104, and a first wavelength laser
  • a diffraction grating 107 that diffracts the light beam 102 and the second wavelength light beam 105 into a 0th-order diffracted light main beam and a ⁇ 1st-order diffracted light sub-beam (not shown), respectively, and linearly polarized light (p-polarized light)
  • a wave plate 108 for polarizing the light beams 102 and 105 into circularly polarized light.
  • the optical pick-up device receives the polarization hologram element 109 that diffracts the light beams 102 and 105 reflected from the first and second optical information recording media 101 and 104, and the diffracted light from the polarization hologram element 109.
  • an integrated circuit substrate 113 on which a first light receiving element group 110, a second light receiving element group 111, and a third light receiving element group 112 are mounted on the same substrate.
  • the first and second semiconductor lasers 103 and 106 are also mounted on the integrated circuit substrate 113.
  • a collimator lens 114, an objective lens 115, and a force S are provided between the wave plate 108 and the optical information recording media 101 and 104.
  • FIG. 1 (a) shows a process until the light beams 102 and 105 emitted from the first and second semiconductor lasers 103 and 106 are condensed on the optical information recording medium 101 and 104.
  • Fig. 1 (b) shows the process until the reflected light beams 102 and 105 from the optical information recording media 101 and 104 are incident on the first, second, and third light receiving element groups 110, 111, and 112. Show.
  • FIG. 2 is a plan view of the polarization hologram element 109.
  • the polarization hologram element 109 includes a first diffraction region 116, a second diffraction region 117, a third diffraction region 118, and a fourth diffraction region 119. It has four diffraction regions. Each diffraction region is divided into strips. In the first diffraction region 116, strip-shaped regions 116a and 116b are alternately formed, and in the second diffraction region 117, strip-shaped regions 117a and 117b are alternately formed. In the folding region 118, strip-shaped regions 118a and 118b are alternately formed, and in the fourth diffraction region 119, strip-shaped regions 119a and 119b are alternately formed.
  • FIG. 3 shows a plan view of the wave plate 108.
  • the wave plate 108 has two different regions 108a and 108b alternately formed in a strip shape. These two different areas that are characteristic of the present invention will be described further below.
  • the plan view of FIG. 4 shows the apparent light emission point L 1 of the first semiconductor laser 103 and the apparent light emission point L 2 of the second semiconductor laser 106.
  • the focal length of the objective lens 115 is fl
  • the focal length of the collimator lens 114 is f2
  • the emission point of the first semiconductor laser 103 and the second semiconductor laser 104 The distance from the light emitting point is a
  • the numerical aperture of the objective lens 115 by the light beam 102 of the first wavelength is NA1
  • the numerical aperture of the objective lens 115 by the beam 105 of the second wavelength is NA2 (NA1> NA2).
  • NA1> NA2 the numerical aperture of the objective lens 115 by the beam 105 of the second wavelength
  • the data is adjusted so as to substantially coincide with the center of the optical axis of the data lens 114.
  • an optical information recording medium to be used is either the first optical information recording medium 101 or the second optical information recording medium 104 by an optical information recording medium discriminating means (not shown). If it is the first optical information recording medium 101, the first wavelength semiconductor laser 103 is driven, and if it is the second optical information recording medium 104, the second optical information recording medium 101 is driven. The semiconductor laser 106 is driven.
  • the light beam 102 (represented by a solid line in FIG. 1) emitted from the semiconductor laser 103 and the light beam 105 (represented by a broken line in FIG. 1) emitted from the semiconductor laser element 106 are transmitted by the diffraction grating 107 next time.
  • the main beam of folding light and the sub beam (not shown) of ⁇ 1st order diffracted light are diffracted, and since it is p-polarized light, polarization hologram element 109 transmits almost 100% 0th order light without being diffracted, On the wave plate 108, the p-polarized light beam 102 or 105 becomes circularly polarized.
  • the circularly polarized light beam 102 or 105 is condensed and reflected on the optical information recording medium 101, 104 via the collimator lens 114 and the objective lens 115, and again the objective lens 115, the collimator lens.
  • the light After passing through 114, the light enters the wave plate 108 and becomes s-polarized light, and enters the polarization hologram element 109 that is a light beam branching unit.
  • the percentage of diffraction is about 20-40%.
  • the light beam 102 of the first wavelength reflected by the optical information recording medium 101 is diffracted in the X direction in the figure by the first diffraction region 116 of the polarization hologram element 109, and ⁇ 1st order diffracted light is converted into the first To the light receiving element group 110 and the third light receiving element group 112, and the second diffraction region 11 7 diffracts in the X direction in the figure, and ⁇ 1st order diffracted light is guided to the first light receiving element group 110 and the third light receiving element group 112.
  • the reflected light beam 102 is diffracted in the X direction in the figure by the third diffraction region 118, and ⁇ 1st order diffracted light is converted into the second light receiving element group 111 and the third light receiving element.
  • the light is guided to the group 112 and diffracted in the X direction in the figure by the fourth diffraction region 119, and ⁇ 1st-order diffracted light is guided to the second light receiving element group 111 and the third light receiving element group 112.
  • the light beam 105 having the second wavelength reflected by the optical information recording medium 104 is diffracted in the X direction by the first diffraction region 116 of the polarization hologram element 109, and ⁇ 1 Is guided to the first light receiving element group 110 and the third light receiving element group 112, and is diffracted in the X direction by the second diffraction region 117, so that ⁇ 1st order diffracted light becomes the first light receiving element group 110.
  • the reflected light beam 105 is diffracted by the third diffraction region 118 in the X direction in the figure, and ⁇ 1st order diffracted light is converted into the second light receiving element group 111 and the third light receiving element. Is guided to the group 112 and is diffracted in the X direction by the fourth diffraction region 119, and ⁇ 1st order diffracted light is guided to the second light receiving element group 111 and the third light receiving element group 112. .
  • a tracking error signal is detected from the light beams 102 and 105 guided to the first and second light receiving element groups 110 and 111, and the light beams 102 and 105 guided to the third light receiving element group 112 are detected.
  • a focus error signal is detected, and recording or reproduction of the first optical information recording medium 101 or the second optical information recording medium 104 is performed using these detection signals.
  • the first light receiving element group 110 to the third light receiving element group 112 are each divided into a plurality of light receiving regions in the Y-axis direction.
  • the first light receiving element group 110 is divided into four light receiving areas 110a, 110b, 110c, 110d in the Y-axis direction, and the second light receiving element group 111 receives four light receiving areas in the Y-axis direction.
  • the third light receiving element group 112 is divided into five light receiving areas 112a, 112b, 112c, 112d, and 112e in the Y-axis direction, and is divided into ij, which is divided into areas 11la, 111b, 111c, and 11Id.
  • the beam spots on the light receiving element group diffracted by the polarization hologram element 109 are Light receiving regions 110a to 110d, 111a to ll ld, 112a to 112e, respectively.
  • the white dots are attributed to the light beam 102 of the first wavelength
  • the black dots are attributed to the light beam 105 of the second wavelength.
  • L101c and L104d represent diffraction spots in which the main beam of the light beam 102 of the first wavelength is diffracted by the first diffraction region 116 of the polarization hologram element 109, and L101a, LlOle, L104b, and L104f are A sub-beam of the light beam 102 of the first wavelength represents a diffraction spot diffracted by the first diffraction region 116 of the polarization hologram element 109.
  • L101d and L104c represent diffraction spots in which the main beam of the light beam 102 of the first wavelength is diffracted by the second diffraction region 117 of the polarization hologram element 109, and L101b, LlOlf, L104a, and L104e are The sub-beam of the first wavelength light beam 102 represents a diffraction spot diffracted by the second diffraction region 117 of the polarization hologram element 109.
  • L102d and L103c represent diffraction spots in which the main beam of the light beam 102 of the first wavelength is diffracted by the third diffraction region 118 of the polarization hologram element 109, and L102b, L102f, L103a, and L103e are A sub-beam of the first wavelength light beam 102 represents a diffraction spot diffracted by the third diffraction region 118 of the polarization hologram element 109.
  • L102c and L103d represent diffraction spots in which the main beam of the light beam 102 of the first wavelength is diffracted by the fourth diffraction region 119 of the polarization hologram element 109, and L102a, L102e, L103b, and L103f are A sub-beam of the first wavelength light beam 102 represents a diffraction spot diffracted by the fourth diffraction region 119 of the polarization hologram element 109.
  • L201c and L204d represent diffraction spots in which the main beam of the light beam 105 of the second wavelength is diffracted by the first diffraction region 116 of the polarization hologram element 109
  • L201a, L201e, L204b, L204f represents a diffraction spot in which the sub beam of the light beam 105 having the second wavelength is diffracted by the first diffraction region 116 of the polarization hologram element 109.
  • L201d and L204c represent diffraction spots in which the main beam of the light beam 105 of the second wavelength is diffracted by the second diffraction region 117 of the polarization hologram element 109, and L201b, L201f, L204a, and L204e are A sub beam of the light beam 105 having the second wavelength represents a diffraction spot diffracted by the second diffraction region 117 of the polarization hologram element 109.
  • the main beam of the light beam 105 having the second wavelength is a polarization hologram element.
  • L202b, L202f, L203c, and L203e represent diffraction spots diffracted by the third diffraction region 118 of the optical element 109. It represents a diffracted diffraction spot.
  • L202c and L203d represent diffraction spots in which the main beam of the light beam 105 of the second wavelength is diffracted by the fourth diffraction region 119 of the polarization hologram element 109, and L202a, L202e, L203b, and L203f are A sub-beam of the second wavelength light beam 105 represents a diffraction spot diffracted by the fourth diffraction region 119 of the polarization hologram element 109.
  • the focus error signal FE is a known SSD (spot). Detect by size detection method. A focus error signal FE1 by the light beam 102 of the first wavelength and the light beam 105 of the second wavelength is obtained by the calculation of the following formula 2.
  • the output signal from the light receiving area 110b is T1
  • the output signal from the light receiving area 110c is T2
  • the output signal from the light receiving area 111c is T3
  • the output signal from the light receiving area 11 lb is T4.
  • the tracking error signal TE is the known DPD (phase difference detection). ) Method and DPP (differential push-pull) method.
  • the tracking error signal TE (DPD) of the DPD method using the light beam 102 of the first wavelength and the light beam 105 of the second wavelength is obtained by the calculation of Equation 3 below.
  • T E (D P D) (Phase comparison between T 1 and T 4) + (Phase comparison between T 2 and T 3)
  • the tracking error signal TE (DPP) of the DPP method using the light beam 102 of the first wavelength and the light beam 105 of the second wavelength is obtained by the calculation of Equation 4 below. [0086] (number 4)
  • TE (D P P) (T 1 + T 2) ⁇ (T 3 + T4) — k (T 5— T 6)
  • Equation 4 is an arbitrary value.
  • the wave plate 108 is divided into two different regions 108a and 108b, respectively, and is arranged so that they are alternately arranged in a strip shape.
  • the reason why the longitudinal direction of the strip is made coincident with the X direction is that the light beams 102 and 105 pass through the same region even if the objective lens 115 is shifted in the X direction.
  • the two different regions 108a and 108b are regions having different phase differences.
  • the former phase difference is ⁇ 1/4 + a and the latter phase difference is ⁇ 1 / 4 ⁇ . It is designed to be ⁇ .
  • ⁇ satisfies 1 ⁇ 1/8 and ⁇ ⁇ 1/8.
  • the wave plate 108 has the two regions 108a and 108b having different phase differences, so that the signal of the optical information recording medium having a large bad birefringence passes through the wave plate 108, and the polarization hologram
  • the ⁇ 1st-order diffracted light does not become zero at the element 109 but is guided to the light receiving element groups 110, 111, and 112, and stable focus error signals and tracking error signals can be obtained.
  • the signal of the optical information recording medium having a large bad birefringence passes through the wave plate 108, and ⁇ 1st order diffracted light becomes 0 by the polarization hologram element 109.
  • the reason why the light receiving element groups 110, 111, and 112 are guided will be described with reference to FIGS. 10 (a) to 11 (b).
  • Figure 10 (a) shows the transmittance of the s-polarized component in the wave plate 108 (vertical axis) with respect to the change in birefringence phase difference of the optical information recording medium (horizontal axis) when the wavelength of the light beam 105 is 11
  • Figure 10 (b) shows the transmittance of the s-polarized component when ⁇ 2.
  • the transmittance of the s-polarized component on the vertical axis is the s-polarization when circularly polarized light is incident on the wave plate 108.
  • the light transmittance is expressed as 1.
  • a focus error signal and a tracking error can be more stably compared with the conventional case even for a signal of an optical information recording medium having a large bad birefringence. A signal can be obtained.
  • Figs. 11 (a) to 11 (b) show the transmittance of the s-polarized component in the two regions 108a and 108b of the wave plate 108, as in Figs. 10 (a) to 10 (b).
  • the reflected light incident on 8 is circularly polarized light
  • the value is smaller than the transmittance power. This is because, as already explained, the two regions of the wave plate 108 in FIG.
  • the configuration is such that one phase difference of two regions is ⁇ 1 ⁇ 4 and the other phase difference is _ 3 ⁇ ⁇ ⁇ 4 (the reverse is also possible) Even if it is done, it is good. This case will be described with reference to FIGS. 12 (a) to 12 (b).
  • Fig. 12 (a) shows the transmittance at the time of 1
  • Fig. 12 (b) shows the transmittance at the time of ⁇ 2.
  • Fig. 1 2 (a) when the birefringence phase difference of the optical information recording medium changes at ⁇ 1 (in Fig. 12 (a), the birefringence phase difference is 1), the wave plate 108 The transmittance of the s-polarized component of each passing light passing through the two regions 108a and 108b simultaneously becomes zero.
  • FIG. 12 (b); I 2 no matter how the birefringence phase difference of the optical information recording medium changes, the two regions 108a and 108b of the wave plate 108 are transmitted simultaneously. The rate will never be 0
  • various types of optical information recording media 101 and 104 differ depending on the light beam 102 having the first wavelength and the light beam 105 having the second wavelength.
  • a focus and tracking error signal is detected by a common light receiving element group for the first wavelength light beam 102 and the second wavelength light beam 105, and a signal system for detecting a focus error signal;
  • the signal system for tracking error signal detection processing can be completely separated, and the signal processing system can be simplified.
  • FIG. 5 schematically shows the configuration of the optical pickup device according to the second embodiment of the present invention.
  • the configuration shown in FIG. 5 is basically the same as that shown in Embodiment 1, except that diffraction grating 107 is formed of glass or resin-like diffraction grating plate 201, and the first An integrated circuit board 113 in which a semiconductor laser 103, a second semiconductor laser 106, a first light receiving element group 110, a second light receiving element group 111, and a third light receiving element group 112 are integrated into one package 202.
  • the diffraction grating plate 201 and the package 202 are integrated.
  • the operation of the optical pickup device of the present embodiment, the detection of the focus error signal, the detection of the tracking error signal, and the operation of the wave plate 108 are the same as in the first embodiment.
  • the present embodiment by integrating the diffraction grating plate 201 and the package 202, it is possible to achieve downsizing, simplification, and cost reduction in the recording / reproducing apparatus.
  • the lattice plate 201 and the package 202 it is possible to reduce the number of parts to be handled and improve the accuracy for assembling.
  • FIG. 6 schematically shows the configuration of the optical pickup device according to the third embodiment of the present invention.
  • the configuration shown in FIG. 6 is basically the same as that shown in Embodiment 1, with the difference being the monolithic two-wavelength in which the first semiconductor laser 103 and the second semiconductor laser 106 are integrated. This is a point formed by the semiconductor laser 301.
  • the operation of the optical pickup device of the present embodiment, the detection of the focus error signal, the detection of the tracking error signal, and the operation of the wave plate 108 are the same as in the first embodiment.
  • the first semiconductor laser 103 and the second semiconductor laser 106 are formed as one monolithic two-wavelength semiconductor laser 301, whereby the first semiconductor laser 103 and the second semiconductor laser 103 are combined.
  • the light beam emission interval of the laser 106 is determined by the assembly accuracy.
  • Monolithic The light beam emission interval of the two-wavelength semiconductor laser 301 is determined by the diffusion accuracy. From this, the light beam emission interval of the monolithic two-wavelength semiconductor laser 301 can be made more accurate.
  • the first and second embodiments are also monolithic two-wavelength semiconductor lasers 30.
  • FIG. 7 is a plan view of diffraction grating 107 of the optical pickup device in the fourth embodiment.
  • the diffraction grating 107 is formed of a first diffraction region 401 and a second diffraction region 402.
  • the first wavelength light beam 102 is diffracted by the first diffraction region 401 of the diffraction grating 107 into the 0th-order diffracted main beam 102M, and the second diffraction region 402 of the diffraction grating 107 + the first-order diffracted light sub-beam 102S1 And _ Diffracted into sub-beam 102S2 of 1st-order diffracted light.
  • the second-wavelength light beam 105 is diffracted into the 0th-order diffracted light main beam 105M in the first diffraction region 501 of the diffraction grating 107, and the first-order diffracted light sub-beam 105S1 in the second diffraction region 402 of the diffraction grating 107. And diffracted into the first-order diffracted light sub-beam 105S2.
  • the second diffraction region 402 of the diffraction grating 107 includes ⁇ 1 sub-beams 102S1 and 102S2 of the first-fold light 102 and the first-wavelength light beam 105 of the first wavelength.
  • the grating depth of the second diffraction region 402 is determined so that the efficiency of the sub beams 105S1 and 105S2 is maximized.
  • the present embodiment it is possible to maximize the intensity of the main beam by forming the first diffraction region 401 of the diffraction grating as a non-lattice region.
  • the first diffraction region 401 is a non-lattice region, a ⁇ first-order diffracted light sub-beam is not generated.
  • the second diffraction region 402 can maximize the sub beam of ⁇ 1st order diffracted light. Therefore, it is possible to maximize the light use efficiency (main beam, sub beam) of the optical pickup device itself.
  • the diffraction grating 1070 shown in Fig. 8 may be used.
  • the grating of the second diffraction region 402 of the diffraction grating 107 shown in FIG. 7 is formed so as to be inclined by a predetermined angle with respect to the first diffraction region 401 formed in a band shape.
  • the reason why the beam spot position adjusting process can be simplified by the diffraction grating 1070 will be described.
  • the diffraction grating 107 shown in FIG. 7 is arranged, the diffraction grating 107 itself is rotated by a predetermined angle so that the main beam is arranged in the group portion of the optical information recording medium and the sub beam is arranged in the land portion. This adjustment process is required.
  • the grating of the second diffraction region 402 is formed in advance with a predetermined angle with respect to the first diffraction region 401 formed in a band shape. It has been. Therefore, the adjustment process of rotating the diffraction grating 1070 itself by a predetermined angle becomes unnecessary, and the position adjustment process can be simplified as a whole.
  • the diffraction grating according to the fourth embodiment can be used in the first embodiment, the second embodiment, and the third embodiment.
  • the configuration of the optical pickup device in the fifth embodiment is basically the same as the configuration of the optical pickup device in the first embodiment, but the integrated circuit board 113 in the fifth embodiment of the present invention. This structure differs from that of the first embodiment in the following points.
  • FIG. 9 is an equivalent circuit diagram of the integrated circuit board 113 of the optical pickup device in the fifth embodiment.
  • the output signal from the light receiving area 110b is converted and amplified by the current-voltage conversion amplifier circuit 501, and then T 1 is output.
  • the output signal from the light receiving area 110c is output by the current-voltage conversion amplifier circuit 502 and output after T2 is output.
  • the output signal from the light receiving region 111c is converted and amplified by the current / voltage conversion amplifier circuit 503, and T3 is output.
  • the output signal from the light receiving region 111b is converted and amplified by the current / voltage conversion amplifier circuit 504, and T4 is output.
  • the sum of the output signals from light receiving area 110a and light receiving area 110d is converted and amplified by current-voltage conversion amplification circuit 505, and then T5 is output.
  • the sum of the output signals from light receiving area 111a and light receiving area ll ld is calculated.
  • Current-voltage conversion amplifier circuit 506 outputs T6 after conversion amplification.
  • the light receiving area The sum of the output signals from the areas 112b and 112d is converted and amplified by the current-voltage conversion amplifier circuit 507, and then F 1 is output.
  • the sum of the output signals from the light-receiving areas 112a, 112c, and 112e is converted and amplified by the current-voltage conversion amplifier circuit 508. After output F2.
  • each output signal in the fifth embodiment becomes a voltage output signal.
  • each signal output Tl, ⁇ 2, ⁇ 3, ⁇ 4, ⁇ 5, ⁇ 6, Fl, F2 is converted into a voltage output signal by a current-voltage conversion amplifier circuit, so that it is external to the current output signal. It becomes resistant to signal noise, and the recording / reproducing speed can be improved by mounting the current-voltage conversion amplifier circuit on the integrated circuit board.
  • the integrated circuit board according to the fifth embodiment can be used in the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment.
  • the first optical information recording medium is a DVD (DVD, DVD-ROM, DVD-RAM, DVD-R, DVD-RW, etc.), and the second The optical information recording medium is a CD (CD, CD-ROM, CD-R, CD-RW, etc.), the first wavelength is about 65 Onm, and the second wavelength is about 780 nm.
  • the present invention is not limited to this, and the polarization hologram element 109 may be configured separately for each wavelength, for example, as in the prior art. In that case, there is no limit to the range defined by Equation 1 for the distance L of the polarization hologram element 109.
  • the wave plate 108 is disposed between the polarization hologram element 109 and the collimator lens 114 .
  • the wave plate 108 may be disposed between the objective lens 115 and the collimator lens 114, for example (see FIGS. 13 (a) and 13 (b)).
  • the optical pickup device described above it is possible to cope with various optical information recording media having different wavelengths of semiconductor laser light to be used, reduce the number of parts, and can be configured more simply and more stably.
  • This enables detection of focus and tracking error signals that realize recording and playback. That is, the optical pickup device according to the present invention can be applied to various optical information recording media and can realize more stable recording / reproduction by using two different semiconductor lasers. The focus and tracking error signals can be detected.
  • DVD- and CD-based recording 'reproduction devices can be made smaller, simpler, and less costly' and more efficient.
  • the optical pickup device of the present invention is an optical component that is a key component in the field of optical information processing devices that perform processing such as information recording, reproduction, and erasing on an optical information recording medium such as an optical disk. It is useful as an optical pickup device having a function of detecting reproduction and Z or recording signals and various servo signals used in the head type device.
  • the optical pickup device can cope with various optical information recording media in which the wavelengths of the semiconductor laser light to be used are different, and more stably the focus error signal and the tracking error signal. It has an effect that it can be detected, and is useful as an optical pickup device or the like.

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  • Optics & Photonics (AREA)
  • Optical Head (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

In a conventional optical pickup device using a two-wavelength semiconductor laser, an optical beam from an inferior optical information recording medium transmits a 1/4 wavelength plate and becomes a p-polarized light instead of an s-polarized light. Accordingly, it is impossible to control a focus tracking error signal. Provided is an optical pickup device including: a first semiconductor laser (103) for emitting an optical beam (102) having a first wavelength corresponding to recording/reproduction to/from a first optical information recording medium (101); a second semiconductor laser (106) for emitting an optical beam (105) having a second wavelength longer than the first semiconductor laser corresponding to a second optical information recording medium (104); a diffraction grating (107) for diffracting an optical beam of the first and the second wavelength into 0 degree diffracted light and plus and minus 1 degree diffracted light; a wavelength plate (108); a polarization hologram element (109) for diffracting a reflected light from the first and the second optical information recording medium; a collimator lens (114); an objective lens (115); and a first light receiving element group (110) to a third light receiving element group (112) for receiving diffracted light from a hologram element.

Description

明 細 書  Specification
光ピックアップ装置  Optical pickup device
技術分野  Technical field
[0001] 本発明は、光ディスクなどの光情報記録媒体に、例えば、情報の記録、再生、消去 などの処理を行う光学式情報処理装置において、その基幹部品である光学式ヘッド 装置に使用される再生及び/又は記録信号及び各種サーボ信号の検出機能を有 する光ピックアップ装置に関する。  [0001] The present invention is used in an optical head device that is a key component in an optical information processing apparatus that performs processing such as information recording, reproduction, and erasing on an optical information recording medium such as an optical disc. The present invention relates to an optical pickup device having a function of detecting reproduction and / or recording signals and various servo signals.
背景技術  Background art
[0002] 現在、光ディスクの中で、最も大きな巿場を形成している CD (Compact Disc)にお いて、その記録 '再生には波長 780nm〜820nm帯の近赤外半導体レーザが用いら れている。一方、急速に普及し、より高記録密度の光情報記録媒体である DVD (Digi tal Versatile Disc)の記録 '再生には、光スポットを小さくするため、より短波長の 635 nm〜680nm帯の赤色半導体レーザが用いられている。これら規格の異なる 2種類 の光ディスクに対して、 1台の装置で記録 ·再生を可能にすることが要求されており、 従来、図 14に示すような再生専用の光ピックアップ装置が考えられている（例えば、 特許文献 1参照）。尚、特開 2004— 87089号公報の文献の全ての開示は、そっくり そのまま引用することにより、ここに一体化する。  [0002] Currently, a near-infrared semiconductor laser having a wavelength of 780 nm to 820 nm is used for recording and reproduction on a CD (Compact Disc) which forms the largest field among optical discs. Yes. On the other hand, recording of DVD (Digital Versatile Disc), an optical information recording medium with a higher recording density, which has spread rapidly, has a shorter wavelength of 635 nm to 680 nm in red for playback. A semiconductor laser is used. For these two types of optical discs with different standards, it is required to be able to record and playback with a single device. Conventionally, a read-only optical pickup device as shown in Fig. 14 has been considered. (For example, see Patent Document 1). It should be noted that the entire disclosure of the document of Japanese Patent Application Laid-Open No. 2004-87089 is incorporated herein by reference as it is.
[0003] 以下、この従来の光ピックアップ装置の動作原理を示す。  [0003] The operation principle of this conventional optical pickup device will be described below.
[0004] 図 14は、集積化レーザユニット 1の詳細図である。以下、図 14に従って、集積化レ 一ザユニット 1について詳細に説明する。集積化レーザユニット 1は、レーザパッケ一 ジ 2と透明基板 3と複合偏光ビームスプリッタ (複合 PBS) 4とが、この順序で基板上に 積層されて構成されている。  FIG. 14 is a detailed view of the integrated laser unit 1. The integrated laser unit 1 will be described in detail below with reference to FIG. The integrated laser unit 1 is configured by laminating a laser package 2, a transparent substrate 3, and a composite polarization beam splitter (composite PBS) 4 in this order on the substrate.
[0005] レーザパッケージ 2には、 650nm帯で発振する第 1半導体レーザ 5および 780nm 帯で発振する第 2半導体レーザ 6が近接配置されて搭載されたレーザ台 7と、光検出 器 8が搭載された検出台 9とが、収納されている。 [0005] The laser package 2 includes a laser stage 7 on which a first semiconductor laser 5 that oscillates in the 650 nm band and a second semiconductor laser 6 that oscillates in the 780 nm band are mounted in close proximity, and a photodetector 8. The detection table 9 is housed.
[0006] また、透明基板 3におけるレーザパッケージ 2に密着する側の面の第 1 ,第 2半導体 レーザ 5, 6に対向する位置には、トラッキング制御用の 3ビームを生じさせる 3ビーム 用回折格子 10が形成されている。さらに、複合 PBS4に密着する側の面には、複合 PBS4から入射される第 1半導体レーザ 5の光ビームを回折して光検出器 8に導く第 1偏光ホログラム素子 11と、複合 PBS4から入射される第 2半導体レーザ 6の光ビー ムを回折して光検出器 8に導く第 2偏光ホログラム素子 12とが形成されている。 [0006] Further, three beams for generating three beams for tracking control are formed at positions facing the first and second semiconductor lasers 5 and 6 on the surface of the transparent substrate 3 that is in close contact with the laser package 2. A diffraction grating 10 is formed. Further, the first polarization hologram element 11 that diffracts the light beam of the first semiconductor laser 5 incident from the composite PBS 4 and guides it to the photodetector 8 is incident on the surface that is in close contact with the composite PBS 4 and the composite PBS 4. A second polarization hologram element 12 that diffracts the optical beam of the second semiconductor laser 6 and guides it to the photodetector 8 is formed.
[0007] また、複合 PBS4は、偏光ビームスプリッタ面 4aと反射面 4bとを有している。そして、 透明基板 3に密着していない側の面上には、波長板 13が積層されている。  [0007] The composite PBS 4 has a polarization beam splitter surface 4a and a reflection surface 4b. A wave plate 13 is laminated on the surface that is not in close contact with the transparent substrate 3.
[0008] ここで、レーザパッケージ 2,透明基板 3,複合 PBS4および波長板 13は、一体に接 着固定されている。  Here, the laser package 2, the transparent substrate 3, the composite PBS 4 and the wave plate 13 are integrally attached and fixed.
[0009] 以下、上記構成を有する光ピックアップによって、異なる光情報記録媒体を再生す る方法について詳細に説明する。  Hereinafter, a method for reproducing different optical information recording media by the optical pickup having the above configuration will be described in detail.
[0010] 先ず、上記 DVDを再生する場合には、 650nm帯の第 1半導体レーザ 5から出射さ れた光ビーム Aは、実線で示すように、 3ビーム用回折格子 10，第 2偏光ホログラム 素子 12,複合 PBS4の偏光ビームスプリッタ面 4aおよび波長板 13を透過して、コリメ ータレンズ（図示せず）に導かれる。 [0010] First, when the DVD is reproduced, the light beam A emitted from the first semiconductor laser 5 in the 650 nm band includes a three-beam diffraction grating 10 and a second polarization hologram element as indicated by a solid line. 12, The light passes through the polarizing beam splitter surface 4a of the composite PBS 4 and the wave plate 13, and is guided to a collimator lens (not shown).
[0011] そして、コリメータレンズ（図示せず）で平行光にされた後、対物レンズ（図示せず） によって光情報記録媒体（図示せず）に集光される。そして、光情報記録媒体（図示 せず）で反射された戻り光 A'は、対物レンズ（図示せず）、コリメータレンズ（図示せず[0011] After collimated light is collimated by a collimator lens (not shown), the light is condensed on an optical information recording medium (not shown) by an objective lens (not shown). The return light A ′ reflected by the optical information recording medium (not shown) is converted into an objective lens (not shown) and a collimator lens (not shown).
)を透過して、集積化レーザユニット 1に導かれる。 ) Is guided to the integrated laser unit 1.
[0012] そして、複合 PBS4の偏光ビームスプリッタ面 4aと反射面 4bとで反射された後、第 1 偏光ホログラム素子 11で回折されて、光検出器 8の受光素子（図示せず）に集光され る。 [0012] Then, after being reflected by the polarization beam splitter surface 4a and the reflection surface 4b of the composite PBS 4, it is diffracted by the first polarization hologram element 11 and condensed on the light receiving element (not shown) of the photodetector 8. It is done.
[0013] これに対して、上記 CDを再生する場合には、 780nm帯の第 2の半導体レーザ 6か ら出射された光ビーム Bは、破線で示すように、 3ビーム用回折格子 10で 3ビームに 分割された後に、第 2偏光ホログラム素子 12，複合 PBS4の偏光ビームスプリッタ面 4 aおよび波長板 13を透過して、コリメータレンズ（図示せず）に導かれる。そして、コリメ ータレンズ（図示せず）で平行光にされた後、対物レンズ（図示せず）によって光情報 記録媒体（図示せず）に集光される。そして、戻り光 B'は、対物レンズ（図示せず）、コ リメータレンズ（図示せず）を透過して、集積化レーザユニット 1に導かれる。そして、 複合 PBS4の偏光ビームスプリッタ面 4aを透過し、第 2偏光ホログラム素子 12で回折 されて、光検出器 8の受光素子に集光される。 [0013] On the other hand, when reproducing the CD, the light beam B emitted from the second semiconductor laser 6 in the 780 nm band is 3 by the diffraction grating 10 for three beams as indicated by a broken line. After being divided into beams, the light passes through the second polarization hologram element 12, the polarization beam splitter surface 4a of the composite PBS 4, and the wave plate 13, and is guided to a collimator lens (not shown). Then, after being collimated by a collimator lens (not shown), it is condensed on an optical information recording medium (not shown) by an objective lens (not shown). Then, the return light B ′ passes through an objective lens (not shown) and a collimator lens (not shown) and is guided to the integrated laser unit 1. And The light passes through the polarization beam splitter surface 4 a of the composite PBS 4, is diffracted by the second polarization hologram element 12, and is condensed on the light receiving element of the photodetector 8.
[0014] また、第 1偏光ホログラム素子 11および第 2偏光ホログラム素子 12は特殊な基板上 に回折格子を刻んで形成されており、透過する光ビームの偏光方向（p偏光， s偏光） によって 0次光と ± 1次光との比率を大きく変動させる素子である。すなわち、透過す るレーザ光ビームが p偏光である場合には略総てが 0次光となり、 ± 1次光は殆ど発 生しない。一方、透過する光ビーム力 偏光である場合には略総てが ± 1次光となり、 0次光は殆ど発生しない。  [0014] The first polarization hologram element 11 and the second polarization hologram element 12 are formed by engraving a diffraction grating on a special substrate, and 0 according to the polarization direction (p-polarization, s-polarization) of the transmitted light beam. It is an element that greatly varies the ratio of the secondary light and ± primary light. That is, when the transmitted laser beam is p-polarized light, almost all of them are 0th order light, and ± 1st order light is hardly generated. On the other hand, when the transmitted light beam is polarized, almost all of the light is ± 1st order light, and almost no 0th order light is generated.
[0015] また、波長板 13は、 650m帯の第 1半導体レーザ 5からの波長に対しては 1/4波 長板として作用する位相差を発生させる一方、 780nm帯の第 2半導体レーザ 6から の波長に対しても 1Z4波長板として作用する位相差を発生させる厚さに設定されて いる。  Further, the wave plate 13 generates a phase difference that acts as a quarter wave plate for the wavelength from the first semiconductor laser 5 in the 650 m band, while the wave plate 13 from the second semiconductor laser 6 in the 780 nm band. The thickness is set so as to generate a phase difference that acts as a 1Z4 wavelength plate for the other wavelengths.
特許文献 1 :特開 2004— 87089号公報  Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-87089
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0016] し力、しながら、一般的には光情報記録媒体の基材は、複屈折性を有していないこと を前提として設計されているが、実際には、一部の粗悪な光情報記録媒体に大きな 複屈折が存在すると、その大きな複屈折によって、粗悪な光情報記録媒体からの光 ビームは 1/4波長板を透過し s偏光にはならず、 p偏光となってしまい、偏光ホロダラ ム素子で回折を受けずに 0次光だけが透過してしまう。そのため、図 14に示すような 従来の光ピックアップ装置では、光検出器に光が入らず、光情報記録媒体からの情 報が読めなくなり、フォーカス誤差信号とトラッキング誤差信号の制御ができなくなつ てしまうという課題 (第 1の課題)がある。  [0016] However, in general, the base material of the optical information recording medium is designed on the assumption that it does not have birefringence. If there is a large birefringence in the information recording medium, the large birefringence causes the light beam from the poor optical information recording medium to pass through the quarter-wave plate and not to be s-polarized, but to be p-polarized, Only the 0th order light is transmitted without being diffracted by the polarization hologram element. For this reason, in the conventional optical pickup device as shown in FIG. 14, light does not enter the photodetector, the information from the optical information recording medium cannot be read, and the focus error signal and tracking error signal cannot be controlled. There is a problem (first problem).
[0017] また、図 14に示すような従来の光ピックアップ装置では、 2つの偏光ホログラム素子 を使用し、さらに複合 PBSを使用しているため、部品点数が増え組立が複雑となると レ、う課題 (第 2の課題)がある。  [0017] In addition, the conventional optical pickup device as shown in Fig. 14 uses two polarization hologram elements and further uses a composite PBS, so that the number of parts increases and the assembly becomes complicated. There is a (second issue).
[0018] そこで、本発明は上記従来の光ピックアップ装置のこの様な課題 (第 1の課題)を考 慮し、使用する半導体レーザ光の波長がそれぞれ異なる各種光情報記録媒体への 対応が可能であると共に、フォーカス誤差信号とトラッキング誤差信号をより安定して 検出することが可能な光ピックアップ装置を提供することを目的とするものである。 Therefore, the present invention takes into consideration such a problem (first problem) of the conventional optical pickup device described above, and can be applied to various optical information recording media having different wavelengths of semiconductor laser light to be used. An object of the present invention is to provide an optical pickup device that can cope with the above and can detect a focus error signal and a tracking error signal more stably.
[0019] また、本発明は上記従来の光ピックアップ装置のこの様な課題 (第 2の課題)を考慮 し、従来に比べて部品点数が少ない光ピックアップ装置を提供することを目的とする ものである。  In addition, the present invention has been made in consideration of the above-described problem (second problem) of the conventional optical pickup device, and an object of the present invention is to provide an optical pickup device having a smaller number of parts than the conventional one. is there.
課題を解決するための手段  Means for solving the problem
[0020] 第 1の本発明は、第 1の波長の光ビームを出射する第 1の半導体レーザと、 [0020] The first aspect of the present invention is a first semiconductor laser that emits a light beam having a first wavelength;
前記第 1の半導体レーザより波長の長い第 2の波長の光ビームを出射する第 2の半 導体レーザと、  A second semiconductor laser that emits a light beam having a second wavelength longer than that of the first semiconductor laser;
前記第 1の波長の光ビームまたは前記第 2の波長の光ビームをそれぞれ異なる次 数の回折光に回折するための回折格子と、  A diffraction grating for diffracting the light beam of the first wavelength or the light beam of the second wavelength into diffracted lights of different orders;
前記回折格子により回折された回折光を平行ビームにするためのコリメータレンズと 前記平行ビームを光情報記録媒体の記録面に集光させるための対物レンズと、 前記光情報記録媒体の記録面により反射された戻り光を回折する偏光ホログラム 素子と、  A collimator lens for converting the diffracted light diffracted by the diffraction grating into a parallel beam; an objective lens for condensing the parallel beam on a recording surface of the optical information recording medium; and reflecting by the recording surface of the optical information recording medium A polarization hologram element that diffracts the reflected return light,
位相に関する特性が異なる領域が短冊状に交互に配置された波長板と、 前記偏光ホログラム素子により回折された回折光を受光する複数の受光素子と、 を備えた光ピックアップ装置である。  An optical pickup device comprising: a wave plate in which regions having different phase-related characteristics are alternately arranged in a strip shape; and a plurality of light receiving elements that receive diffracted light diffracted by the polarization hologram element.
[0021] また、第 2の本発明は、前記回折格子は、前記光ビームをそれぞれ 0次回折光と ±[0021] Further, according to the second aspect of the present invention, the diffraction grating is configured such that the light beam is divided into 0-order diffracted light and
1次回折光に回折する、上記第 1の本発明の光ピックアップ装置である。 The optical pickup device according to the first aspect of the present invention diffracts into first-order diffracted light.
[0022] また、第 3の本発明は、前記波長板が、 2つの異なる特性の前記領域が短冊状に 交互に配置された波長板であり、 [0022] Further, in the third aspect of the present invention, the wave plate is a wave plate in which the regions having two different characteristics are alternately arranged in a strip shape,
前記第 1の波長の光ビームの波長を λ 1とするとき、前記 2つの異なる特性の一方 の特性の領域の位相差がえ 1/4 + aであり、他方の特性の領域の位相差が λ 1/ 4一 αであり、且つ前記 αが— λ 1/8 < α < λ 1/8である、上記第 1または 2の本 発明の光ピックアップ装置である。  When the wavelength of the light beam of the first wavelength is λ1, the phase difference of one of the two different characteristics is 1/4 + a, and the phase difference of the other characteristic is The optical pickup device according to the first or second aspect of the present invention, wherein λ 1/4 is α, and α is −λ 1/8 <α <λ 1/8.
[0023] また、第 4の本発明は、前記波長板が、 2つの異なる特性の前記領域が短冊状に 交互に配置された波長板であり、 [0023] Further, according to a fourth aspect of the present invention, the wave plate has a strip shape in which the two regions having different characteristics are formed. Wave plates arranged alternately,
前記第 1の波長の光ビームの波長を λ 1とするとき、前記 2つの異なる特性の一方 の特性の領域の位相差がえ 1/4であり、他方の特性の領域の位相差が 3 X λ 1 /4である、上記第 1または 2の本発明の光ピックアップ装置である。  When the wavelength of the light beam of the first wavelength is λ1, the phase difference of one of the two different characteristics is 1/4, and the phase difference of the other characteristic is 3 × The optical pickup device according to the first or second aspect of the present invention, wherein λ 1/4.
[0024] また、第 5の本発明は、前記波長板は、前記対物レンズと前記コリメータレンズの間 に設けられている、上記第 1〜4のいずれかの本発明の光ピックアップ装置である。  The fifth aspect of the present invention is the optical pickup device according to any one of the first to fourth aspects, wherein the wave plate is provided between the objective lens and the collimator lens.
[0025] また、第 6の本発明は、前記偏光ホログラムは、前記回折格子と前記コリメータレン ズの間に設けられている、上記第 1〜5のいずれかの本発明の光ピックアップ装置で ある。  The sixth invention is the optical pickup device according to any one of the first to fifth inventions, wherein the polarization hologram is provided between the diffraction grating and the collimator lens. .
[0026] また、第 7の本発明は、前記波長板と前記偏光ホログラム素子とがー体的に構成さ れている、上記第 1〜6のいずれかの本発明の光ピックアップ装置である。  The seventh aspect of the present invention is the optical pickup device according to any one of the first to sixth aspects of the present invention, wherein the wave plate and the polarization hologram element are configured in a body.
[0027] また、第 8の本発明は、前記対物レンズの焦点距離を fl、前記コリメータレンズの焦 点距離を f2、光学倍率を （ = f2/fl)、前記第 1の半導体レーザの発光点と前記 第 2の半導体レーザの発光点間隔を a、前記第 1の波長のビームによる前記対物レン ズの開口数を NA1、前記第 2の波長のビームによる前記対物レンズの開口数を NA 2、（NA1 >NA2とする）、前記第 1の半導体レーザの発光点から前記偏光ホロダラ ム素子までの距離を Lとしたとき、  [0027] The eighth aspect of the present invention is that the focal length of the objective lens is fl, the focal length of the collimator lens is f2, the optical magnification is (= f2 / fl), and the emission point of the first semiconductor laser is And the emission point interval of the second semiconductor laser is a, the numerical aperture of the objective lens by the beam of the first wavelength is NA1, the numerical aperture of the objective lens by the beam of the second wavelength is NA2, (NA1> NA2), when the distance from the light emitting point of the first semiconductor laser to the polarization hologram element is L,
(数 1) a X j3 / ( N A 2 - 0 . 6 7 X N A 1 ) ≤ L < f 2 を満たす距離 Lの位置に前記偏光ホログラム素子が配置されている、上記第 6または (Equation 1) The polarization hologram element is arranged at a position of a distance L that satisfies a X j3 / (NA 2-0.67 XNA1) ≤ L <f2,
7の本発明の光ピックアップ装置である。 7 is an optical pickup device of the present invention.
[0028] また、第 9の本発明は、前記偏光ホログラム素子は、 4領域に分割されており、且つ それぞれの前記領域において 2つの異なる回折特性を持つ領域が短冊状に交互に 配置されている、上記第 1〜8のいずれかの本発明の光ピックアップ装置である。 [0028] Further, in the ninth aspect of the present invention, the polarization hologram element is divided into four regions, and regions having two different diffraction characteristics are alternately arranged in a strip shape in each of the regions. The optical pickup device according to any one of the first to eighth aspects of the present invention.
[0029] また、第 10の本発明は、前記第 1の半導体レーザの光軸と、前記偏光ホログラム素 子の前記 4領域の中心とが、前記コリメータレンズの光軸中心と実質上一致しているIn the tenth aspect of the present invention, the optical axis of the first semiconductor laser and the center of the four regions of the polarization hologram element substantially coincide with the optical axis center of the collimator lens. Have
、上記第 9の本発明の光ピックアップ装置である。 [0030] また、第 11の本発明は、前記受光素子は、前記第 1の半導体レーザおよび前記第 2の半導体レーザの両側に前記第 1の半導体レーザおよび前記第 2の半導体レーザ と離間して、かつ前記第 1の半導体レーザにおける光出射位置と前記第 2の半導体 レーザにおける光出射位置とを結ぶ延長線上に配置されており、 This is the ninth optical pickup apparatus of the present invention. [0030] Further, according to an eleventh aspect of the present invention, the light receiving element is separated from the first semiconductor laser and the second semiconductor laser on both sides of the first semiconductor laser and the second semiconductor laser. And arranged on an extension line connecting the light emission position in the first semiconductor laser and the light emission position in the second semiconductor laser,
前記第 1の半導体レーザ力 見て前記第 2の半導体レーザの反対側に配置された 前記受光素子数が、前記第 2の半導体レーザから見て前記第 1の半導体レーザの反 対側に配置された前記受光素子数よりも少なレ、、上記第 1〜： 10のいずれかの本発明 の光ピックアップ装置である。  The number of light receiving elements arranged on the opposite side of the second semiconductor laser with respect to the first semiconductor laser force is arranged on the opposite side of the first semiconductor laser with respect to the second semiconductor laser. The optical pickup device according to any one of the first to tenth aspects, wherein the number is less than the number of the light receiving elements.
[0031] また、第 12の本発明は、前記光情報記録媒体の記録面から反射された前記第 1の 波長の光ビーム、又は前記第 2の波長の光ビームは、前記偏光ホログラム素子により 回折され、回折光を共通の受光素子で受光する、上記第 1〜： 11のいずれかの本発 明の光ピックアップ装置である。  [0031] Further, in the twelfth aspect of the present invention, the light beam having the first wavelength or the light beam having the second wavelength reflected from the recording surface of the optical information recording medium is diffracted by the polarization hologram element. The optical pickup device according to any one of the first to eleventh aspects, wherein the diffracted light is received by a common light receiving element.
[0032] また、第 13の本発明は、前記受光素子からの信号に基づいてフォーカス及びトラッ キング誤差信号を得る、上記第 12の本発明の光ピックアップ装置である。  The thirteenth aspect of the present invention is the optical pickup apparatus according to the twelfth aspect of the present invention, wherein a focus and tracking error signal is obtained based on a signal from the light receiving element.
[0033] また、第 14の本発明は、前記第 1の半導体レーザから見て前記第 2の半導体レー ザの反対側に配置された前記受光素子でフォーカス誤差信号を得、前記第 2の半導 体レーザから見て前記第 1の半導体レーザの反対側に配置された前記受光素子でト ラッキング誤差信号を得る、上記第 13の本発明の光ピックアップ装置である。  [0033] Further, in the fourteenth aspect of the present invention, a focus error signal is obtained by the light receiving element disposed on the opposite side of the second semiconductor laser as viewed from the first semiconductor laser, and the second semiconductor laser is obtained. The optical pickup device according to the thirteenth aspect of the present invention, wherein a tracking error signal is obtained by the light receiving element disposed on the opposite side of the first semiconductor laser as viewed from a conductor laser.
[0034] また、第 15の本発明は、前記第 1の半導体レーザと前記第 2の半導体レーザと前 記複数の受光素子とが、同一の集積回路基板上に搭載されている、上記第 1〜： 14 のいずれかの本発明の光ピックアップ装置である。  [0034] Further, in the fifteenth aspect of the present invention, the first semiconductor laser, the second semiconductor laser, and the plurality of light receiving elements are mounted on the same integrated circuit substrate. ~: The optical pickup device according to any one of 14 above.
[0035] また、第 16の本発明は、前記集積回路基板上に、 2つのフォーカス誤差信号用電 流電圧変換増幅回路と、 6つのトラッキング誤差信号用電流電圧変換増幅回路が搭 載されている、上記第 15の本発明の光ピックアップ装置である。  In the sixteenth aspect of the present invention, two focus error signal current-voltage conversion amplifier circuits and six tracking error signal current-voltage conversion amplifier circuits are mounted on the integrated circuit board. This is the optical pickup apparatus of the fifteenth aspect of the present invention.
[0036] また、第 17の本発明は、前記集積回路基板と前記回折格子とが、 1つのパッケ一 ジに搭載されている、上記第 15または 16の本発明の光ピックアップ装置である。  The 17th aspect of the present invention is the optical pickup apparatus according to the 15th or 16th aspect of the present invention, wherein the integrated circuit substrate and the diffraction grating are mounted in one package.
[0037] また、第 18の本発明は、前記第 1の半導体レーザと前記第 2の半導体レーザとが、 1つのモノリツシック半導体レーザで構成されている、上記第 1〜17のいずれかの本 発明の光ピックアップ装置である。 [0037] The eighteenth aspect of the present invention is the book according to any one of the first to seventeenth aspects, wherein the first semiconductor laser and the second semiconductor laser are formed of one monolithic semiconductor laser. It is an optical pickup device of the invention.
[0038] また、第 19の本発明は、前記回折格子は、互いに回折効率の異なる第 1の回折領 域および第 2の回折領域を有し、  [0038] Further, in the nineteenth aspect of the present invention, the diffraction grating includes a first diffraction region and a second diffraction region having different diffraction efficiencies,
前記第 1の回折領域における 0次回折光の回折効率は、前記第 2の回折領域にお ける 0次回折光の回折効率よりも大きぐ  The diffraction efficiency of the 0th order diffracted light in the first diffraction region is larger than the diffraction efficiency of the 0th order diffracted light in the second diffraction region.
前記第 1の回折領域および前記第 2の回折領域は帯状に形成され、  The first diffraction region and the second diffraction region are formed in a band shape,
前記第 1の回折領域における格子及び Z又は前記第 2の回折領域における格子 が、前記第 1の回折領域に対して傾斜している、上記第 1〜： 18のいずれかの本発明 の光ピックアップ装置である。  The optical pickup according to any one of the first to 18th aspects, wherein the grating in the first diffraction region and Z or the grating in the second diffraction region are inclined with respect to the first diffraction region. Device.
[0039] また、第 20の本発明は、前記第 1の回折領域において生成される 0次回折光が、 前記光情報記録媒体に対して情報信号を記録又は再生するためのメインビームとし て用いられ、 In the twentieth aspect of the present invention, the 0th-order diffracted light generated in the first diffraction region is used as a main beam for recording or reproducing an information signal to or from the optical information recording medium. ,
前記第 2の回折領域において生成される ± 1次回折光が、サブビームとして用いら れる、上記第 19の本発明の光ピックアップ装置である。  The ± 1st-order diffracted light generated in the second diffraction region is used as a sub beam. The optical pickup apparatus according to the nineteenth aspect of the present invention.
発明の効果  The invention's effect
[0040] 本発明の光ピックアップ装置によれば、使用する半導体レーザ光の波長がそれぞ れ異なる各種光情報記録媒体への対応が可能であると共に、フォーカス誤差信号と トラッキング誤差信号をより安定して検出することが可能となるという効果を発揮する。  [0040] According to the optical pickup device of the present invention, it is possible to cope with various optical information recording media in which the wavelength of the semiconductor laser light to be used is different, and the focus error signal and the tracking error signal are more stable. The effect that it becomes possible to detect is demonstrated.
[0041] また、本発明の光ピックアップ装置によれば、部品点数をより低減することが可能と なるという効果を発揮する。 [0041] Further, according to the optical pickup device of the present invention, it is possible to further reduce the number of parts.
図面の簡単な説明  Brief Description of Drawings
[0042] [図 l] (a)、（b) :本発明の実施の形態 1の光ピックアップ装置の光学系主要部の構成 を示す概略断面図  [0042] [Fig. L] (a), (b): Schematic cross-sectional views showing the configuration of the main part of the optical system of the optical pickup device according to the first embodiment of the present invention.
[図 2]本発明の実施の形態 1の偏光ホログラム素子の構成を示す平面図  FIG. 2 is a plan view showing the configuration of the polarization hologram element according to the first embodiment of the present invention.
[図 3]本発明の実施の形態 1の波長板の構成を示す平面図  FIG. 3 is a plan view showing the configuration of the wave plate according to the first embodiment of the present invention.
[図 4]本発明の実施の形態 1の受光素子の構成を示す平面図  FIG. 4 is a plan view showing the configuration of the light receiving element according to the first embodiment of the present invention.
[図 5]本発明の実施の形態 2の光ピックアップ装置の光学系主要部の構成を示す概 略断面図 [図 6]本発明の実施の形態 3の光ピックアップ装置の光学系主要部の構成を示す概 略断面図 FIG. 5 is a schematic cross-sectional view showing the configuration of the main part of the optical system of the optical pickup device according to the second embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing the configuration of the main part of the optical system of the optical pickup device according to the third embodiment of the present invention.
[図 7]本発明の実施の形態 4における光ピックアップ装置の回折格子の平面図  FIG. 7 is a plan view of a diffraction grating of an optical pickup device in Embodiment 4 of the present invention.
[図 8]本発明の実施の形態 4における光ピックアップ装置の回折格子の別の例の平 面図 FIG. 8 is a plan view of another example of the diffraction grating of the optical pickup device in the fourth embodiment of the present invention.
[図 9]実施の形態 5における光ピックアップ装置の集積回路基板の等価回路図  FIG. 9 is an equivalent circuit diagram of the integrated circuit board of the optical pickup device in the fifth embodiment.
[図 10] (a)光ビーム 105の波長が; 1 1であって、 ひ = λ lZlOの時の、光情報記録媒 体の複屈折位相差の変化 (横軸）に対する、波長板 108における s偏光成分の透過 率（縦軸）を示す図、 （b) λ 2の時の s偏光成分の透過率を示す図  [FIG. 10] (a) When the wavelength of the light beam 105 is; 1 1 and h = λ lZlO, the change in the birefringence phase difference of the optical information recording medium (horizontal axis) Figure showing the transmittance (vertical axis) of the s-polarized component, (b) Figure showing the transmittance of the s-polarized component at λ 2
[図 11] (a)光ビーム 105の波長が; 1 1であって、 ひ = λ 1Ζ8の時の、光情報記録媒 体の複屈折位相差の変化に対する、波長板 108における s偏光成分の透過率を示 す図、（b) λ 2の時の s偏光成分の透過率を示す図  [FIG. 11] (a) When the wavelength of the light beam 105 is; 1 1 and ひ = λ 1 Ζ8, Diagram showing transmittance, (b) Diagram showing transmittance of s-polarized component at λ 2
[図 12] (a)光ビーム 105の波長がえ 1であって、光情報記録媒体の複屈折位相差の 変化に対する、波長板 108における s偏光成分の透過率を示す図、 （b)え 2の時の s 偏光成分の透過率を示す図  [FIG. 12] (a) A diagram showing the transmittance of the s-polarized component in the wave plate 108 with respect to the change in the birefringence phase difference of the optical information recording medium when the wavelength of the light beam 105 is 1, (b) Diagram showing transmittance of s-polarized component at 2
[図 13] (a)、 (b)：本発明の実施の形態 1の光ピックアップ装置の光学系主要部の別 の構成例を示す概略断面図  [FIG. 13] (a), (b): Schematic sectional views showing another configuration example of the main part of the optical system of the optical pickup device according to the first embodiment of the present invention.
[図 14]従来の光ピックアップ装置を示す模式図  FIG. 14 is a schematic diagram showing a conventional optical pickup device.
符号の説明 Explanation of symbols
1 集積化レーザユニット 1 Integrated laser unit
2 レーザパッケージ 2 Laser package
3 透明基板 3 Transparent substrate
4 複合偏光ビームスプリッタ  4 Compound polarization beam splitter
5 第 1半導体レーザ  5 First semiconductor laser
6 第 2半導体レーザ  6 Second semiconductor laser
7 レーザ台  7 Laser stand
8 光検出器 3ビーム用回折格子 第 1偏光ホログラム素子 第 2偏光ホログラム素子 波長板 8 photodetector Three-beam diffraction grating First polarization hologram element Second polarization hologram element Wave plate
第 1の光情報記録媒体 第 1の波長の光ビーム 第 1の半導体レーザ 第 2の光情報記録媒体 第 2の波長の光ビーム 第 2の半導体レーザ 回折格子  First optical information recording medium First wavelength light beam First semiconductor laser Second optical information recording medium Second wavelength light beam Second semiconductor laser Diffraction grating
波長板  Wave plate
偏光ホログラム素子 第 1の受光素子群 第 2の受光素子群 第 3の受光素子群 集積回路基板  Polarization hologram element First light receiving element group Second light receiving element group Third light receiving element group Integrated circuit board
コリメータレンズ  Collimator lens
対物レンズ  Objective lens
第 1の回折領域  First diffraction region
、 1070 第 2の回折領域 第 3の回折領域 1070 Second diffraction region Third diffraction region
第 4の回折領域  Fourth diffraction region
回折格子板  Diffraction grating plate
パッケージ  The package
モノリツシック 2波長半導体レ 回折格子の第 1の回折領域 回折格子の第 2の回折領域 501〜508 電流電圧変換増幅回路 Monolithic two-wavelength semiconductor laser first diffraction region of diffraction grating second diffraction region of diffraction grating 501 to 508 Current-voltage conversion amplifier circuit
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0044] 以下、図面を参照しながら、本発明による実施の形態を説明する。  Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
[0045] (実施の形態 1)  [0045] (Embodiment 1)
図 1は、本発明の実施の形態 1における光ピックアップ装置の構成を模式的に示し ている。図 2は本発明の実施の形態 1における偏光ホログラム素子を示している。図 3 は本発明の実施の形態 1における波長板を示している。図 4は本発明の実施の形態 1における受光素子の構成を示す平面図である。  FIG. 1 schematically shows the configuration of the optical pickup device according to the first embodiment of the present invention. FIG. 2 shows a polarization hologram element according to Embodiment 1 of the present invention. FIG. 3 shows a wave plate according to Embodiment 1 of the present invention. FIG. 4 is a plan view showing the configuration of the light receiving element according to Embodiment 1 of the present invention.
[0046] 図 1に示した光ピックアップ装置は、第 1の光情報記録媒体 101の記録 '再生に対 応した第 1の波長の光ビーム 102を出射する第 1の半導体レーザ 103と、第 2の光情 報記録媒体 104の記録'再生に対応した、第 1の半導体レーザ 103よりも波長の長い 第 2の波長の光ビーム 105を出射する第 2の半導体レーザ 106と、第 1の波長の光ビ ーム 102と第 2の波長の光ビーム 105を、それぞれ 0次回折光のメインビームと ± 1次 回折光のサブビーム（図示せず）に回折する回折格子 107と、直線偏光 (p偏光）の 光ビーム 102、 105を円偏光に偏光する波長板 108とを備えている。更に光ピックァ ップ装置は、第 1、第 2の光情報記録媒体 101、 104から反射してくる光ビーム 102、 105を回折する偏光ホログラム素子 109と、偏光ホログラム素子 109からの回折光を 受光する第 1の受光素子群 110、第 2の受光素子群 111、第 3の受光素子群 112を 同一の基板上に搭載した集積回路基板 113とを備えている。また、集積回路基板 11 3には、第 1及び第 2の半導体レーザ 103, 106も搭載されている。  The optical pickup device shown in FIG. 1 includes a first semiconductor laser 103 that emits a light beam 102 having a first wavelength corresponding to recording and reproduction on the first optical information recording medium 101, and a second semiconductor laser 103. A second semiconductor laser 106 that emits a light beam 105 having a second wavelength longer than that of the first semiconductor laser 103, corresponding to recording and reproduction of the optical information recording medium 104, and a first wavelength laser A diffraction grating 107 that diffracts the light beam 102 and the second wavelength light beam 105 into a 0th-order diffracted light main beam and a ± 1st-order diffracted light sub-beam (not shown), respectively, and linearly polarized light (p-polarized light) And a wave plate 108 for polarizing the light beams 102 and 105 into circularly polarized light. Further, the optical pick-up device receives the polarization hologram element 109 that diffracts the light beams 102 and 105 reflected from the first and second optical information recording media 101 and 104, and the diffracted light from the polarization hologram element 109. And an integrated circuit substrate 113 on which a first light receiving element group 110, a second light receiving element group 111, and a third light receiving element group 112 are mounted on the same substrate. In addition, the first and second semiconductor lasers 103 and 106 are also mounted on the integrated circuit substrate 113.
[0047] また、波長板 108と光情報記録媒体 101、 104との間には、コリメータレンズ 114と、 対物レンズ 115と力 S設けられてレ、る。  Further, a collimator lens 114, an objective lens 115, and a force S are provided between the wave plate 108 and the optical information recording media 101 and 104.
[0048] 図 1 (a)は第 1、第 2の半導体レーザ 103、 106からの出射の光ビーム 102、 105が 光情報記録媒体 101、 104に集光するまでの過程を示している。図 1 (b)は光情報記 録媒体 101、 104からの反射の光ビーム 102、 105が第 1、第 2、第 3の受光素子群 1 10、 11 1、 112に入射するまでの過程を示している。  FIG. 1 (a) shows a process until the light beams 102 and 105 emitted from the first and second semiconductor lasers 103 and 106 are condensed on the optical information recording medium 101 and 104. Fig. 1 (b) shows the process until the reflected light beams 102 and 105 from the optical information recording media 101 and 104 are incident on the first, second, and third light receiving element groups 110, 111, and 112. Show.
[0049] 図 2は、偏光ホログラム素子 109の平面図を示し、偏光ホログラム素子 109は、第 1 の回折領域 116、第 2の回折領域 117、第 3の回折領域 118、第 4の回折領域 119 の 4つの回折領域を有している。それぞれの回折領域は短冊状に分割されている。 第 1の回折領域 116は 116a、 116bの短冊状の領域が交互に形成されており、第 2 の回折領域 117は 117a、 117bの短冊状の領域が交互に形成されており、第 3の回 折領域 118は 118a、 118bの短冊状の領域が交互に形成されており、第 4の回折領 域 119は 119a、 119bの短冊状の領域が交互に形成されてレ、る。 FIG. 2 is a plan view of the polarization hologram element 109. The polarization hologram element 109 includes a first diffraction region 116, a second diffraction region 117, a third diffraction region 118, and a fourth diffraction region 119. It has four diffraction regions. Each diffraction region is divided into strips. In the first diffraction region 116, strip-shaped regions 116a and 116b are alternately formed, and in the second diffraction region 117, strip-shaped regions 117a and 117b are alternately formed. In the folding region 118, strip-shaped regions 118a and 118b are alternately formed, and in the fourth diffraction region 119, strip-shaped regions 119a and 119b are alternately formed.
[0050] 図 3は、波長板 108の平面図を示し、波長板 108は、 2つの異なる領域 108a、 108 bが短冊状に交互に形成されている。本願発明の特徴であるこの 2つの異なる領域に ついては、更に後述する。  FIG. 3 shows a plan view of the wave plate 108. The wave plate 108 has two different regions 108a and 108b alternately formed in a strip shape. These two different areas that are characteristic of the present invention will be described further below.
[0051] 図 4の平面図には第 1の半導体レーザ 103の見かけの発光点 Ll、第 2の半導体レ 一ザ 106の見かけの発光点 L2を示してレ、る。  The plan view of FIG. 4 shows the apparent light emission point L 1 of the first semiconductor laser 103 and the apparent light emission point L 2 of the second semiconductor laser 106.
[0052] 対物レンズ 115の焦点距離を fl、コリメータレンズ 114の焦点距離を f 2、光学倍率 を β ( = f2/fl)、第 1の半導体レーザ 103の発光点と第 2の半導体レーザ 104の発 光点との間隔を a、第 1の波長の光ビーム 102による対物レンズ 115の開口数を NA1 、第 2の波長のビーム 105による対物レンズ 115の開口数を NA2 (NA1 >NA2とす る）、第 1の半導体レーザ 103の発光点から偏光ホログラム素子 109までの距離をしと したとき、下記数式 1を満たす距離 Lの位置に偏光ホログラム素子 109が配置されて いる。  [0052] The focal length of the objective lens 115 is fl, the focal length of the collimator lens 114 is f2, the optical magnification is β (= f2 / fl), the emission point of the first semiconductor laser 103 and the second semiconductor laser 104 The distance from the light emitting point is a, the numerical aperture of the objective lens 115 by the light beam 102 of the first wavelength is NA1, and the numerical aperture of the objective lens 115 by the beam 105 of the second wavelength is NA2 (NA1> NA2). ), When the distance from the light emitting point of the first semiconductor laser 103 to the polarization hologram element 109 is taken, the polarization hologram element 109 is arranged at a distance L satisfying the following formula 1.
[0053] (数 1) a X ]3 / ( N A 2 - 0 . 6 7 X N A 1 ) ≤ Lく f 2  [0053] (Equation 1) a X] 3 / (N A 2-0. 6 7 X N A 1) ≤ L
[0054] ここで、距離 Lを数式 1の範囲に制限した理由について簡単に説明する。 Here, the reason why the distance L is limited to the range of Formula 1 will be briefly described.
[0055] 対物レンズ 115のシフト量（図 1の X方向）が、たとえ 0. 1mmまで移動しても、第 1の 半導体レーザ 103と第 2の半導体レーザ 106の出射ビーム 102, 105からのプッシュ プノレ信号のバランス中立位置力 安定してプッシュプノレ信号を検出できるために、偏 光ホログラム素子 109の位置としての距離 Lの範囲を、上記の数式 1に示す様に規定 した。 [0055] Even if the shift amount of the objective lens 115 (X direction in FIG. 1) moves to 0.1 mm, the push from the outgoing beams 102 and 105 of the first semiconductor laser 103 and the second semiconductor laser 106 The balance neutral position force of the punore signal In order to be able to detect the push pnore signal stably, the range of the distance L as the position of the polarization hologram element 109 is defined as shown in the above equation 1.
[0056] 本実施の形態の光ピックアップ装置では、図 1 (a)に示す様に、第 1の半導体レー ザ 103の光ビーム 102の光軸と、偏光ホログラム素子 109の 4領域の中心と力 S、コリメ ータレンズ 114の光軸中心と実質上一致する様に調整されてレ、る。 In the optical pickup device of the present embodiment, as shown in FIG. 1 (a), the optical axis of the light beam 102 of the first semiconductor laser 103, the center of the four regions of the polarization hologram element 109, and the force S, collimate The data is adjusted so as to substantially coincide with the center of the optical axis of the data lens 114.
[0057] 尚、「実質上一致する」様に調整するとは、厳密な意味での一致に限定されるもの ではなぐあくまで組み立て誤差の範囲内であって、当該技術分野のいわゆる当業 者が社会通念状一致すると判断できる範囲内での一致を含むものである。 [0057] It should be noted that the adjustment to "substantially match" is not limited to matching in a strict sense, but is only within the range of assembly error, and a so-called person skilled in the art may It includes a match within a range where it can be determined that the common sense matches.
[0058] 次に、本実施の形態の光ピックアップ装置の動作を説明する。 Next, the operation of the optical pickup device of the present embodiment will be described.
[0059] まず最初に、基本的な動作について説明する。その後、大きな複屈折を有する粗 悪な光情報記録媒体を使用した場合の動作を、波長板 108 (図 3参照）の説明と合 わせて詳細に説明する。 First, the basic operation will be described. Thereafter, the operation when a bad optical information recording medium having a large birefringence is used will be described in detail together with the description of the wave plate 108 (see FIG. 3).
[0060] 基本的な動作としては、光情報記録媒体判別手段（図示せず）により、使用する光 情報記録媒体が第 1の光情報記録媒体 101もしくは第 2の光情報記録媒体 104のど ちらであるかが判別され、第 1の光情報記録媒体 101である場合は、第 1の波長の半 導体レーザ 103が駆動され、第 2の光情報記録媒体 104である場合は、第 2の波長 の半導体レーザ 106が駆動される。 [0060] As a basic operation, an optical information recording medium to be used is either the first optical information recording medium 101 or the second optical information recording medium 104 by an optical information recording medium discriminating means (not shown). If it is the first optical information recording medium 101, the first wavelength semiconductor laser 103 is driven, and if it is the second optical information recording medium 104, the second optical information recording medium 101 is driven. The semiconductor laser 106 is driven.
[0061] 半導体レーザ 103から出射した光ビーム 102 (図 1において実線で表す)及び半導 体レーザ素子 106から出射した光ビーム 105 (図 1において破線で表す）は、回折格 子 107で 0次回折光のメインビームと ± 1次回折光のサブビーム（図示せず）に回折 を受け、 p偏光の光であるので偏光ホログラム素子 109では、回折を受けずに略 100 %の 0次光が透過し、波長板 108で、 p偏光の光ビーム 102または 105は円偏光にな る。 [0061] The light beam 102 (represented by a solid line in FIG. 1) emitted from the semiconductor laser 103 and the light beam 105 (represented by a broken line in FIG. 1) emitted from the semiconductor laser element 106 are transmitted by the diffraction grating 107 next time. The main beam of folding light and the sub beam (not shown) of ± 1st order diffracted light are diffracted, and since it is p-polarized light, polarization hologram element 109 transmits almost 100% 0th order light without being diffracted, On the wave plate 108, the p-polarized light beam 102 or 105 becomes circularly polarized.
[0062] そして、円偏光になった光ビーム 102または 105は、コリメータレンズ 114、対物レ ンズ 115を経て光情報記録媒体 101、 104上に集光'反射され、再び対物レンズ 11 5、コリメータレンズ 114を経て、波長板 108に入射して s偏光となり、光ビーム分岐手 段である偏光ホログラム素子 109に入射する。  [0062] Then, the circularly polarized light beam 102 or 105 is condensed and reflected on the optical information recording medium 101, 104 via the collimator lens 114 and the objective lens 115, and again the objective lens 115, the collimator lens. After passing through 114, the light enters the wave plate 108 and becomes s-polarized light, and enters the polarization hologram element 109 that is a light beam branching unit.
[0063] そして、偏光ホログラム素子 109によって ± 1次光に回折される。回折される割合は 20〜40%程度である。  Then, it is diffracted into ± first-order light by the polarization hologram element 109. The percentage of diffraction is about 20-40%.
[0064] 光情報記録媒体 101で反射された第 1の波長の光ビーム 102は、偏光ホログラム 素子 109の第 1の回折領域 116によって図中 X方向に回折を受け、 ± 1次回折光が 第 1の受光素子群 110と第 3の受光素子群 112へと導かれ、また第 2の回折領域 11 7によって図中 X方向に回折を受け、 ± 1次回折光が第 1の受光素子群 110と第 3の 受光素子群 112へと導かれる。また、上記と同様に、反射された光ビーム 102は、第 3の回折領域 118によって図中 X方向に回折を受け、 ± 1次回折光が第 2の受光素 子群 111と第 3の受光素子群 112へと導かれ、また第 4の回折領域 119によって図中 X方向に回折を受け、 ± 1次回折光が第 2の受光素子群 111と第 3の受光素子群 11 2へと導かれる。 [0064] The light beam 102 of the first wavelength reflected by the optical information recording medium 101 is diffracted in the X direction in the figure by the first diffraction region 116 of the polarization hologram element 109, and ± 1st order diffracted light is converted into the first To the light receiving element group 110 and the third light receiving element group 112, and the second diffraction region 11 7 diffracts in the X direction in the figure, and ± 1st order diffracted light is guided to the first light receiving element group 110 and the third light receiving element group 112. Similarly to the above, the reflected light beam 102 is diffracted in the X direction in the figure by the third diffraction region 118, and ± 1st order diffracted light is converted into the second light receiving element group 111 and the third light receiving element. The light is guided to the group 112 and diffracted in the X direction in the figure by the fourth diffraction region 119, and ± 1st-order diffracted light is guided to the second light receiving element group 111 and the third light receiving element group 112.
[0065] 一方、光情報記録媒体 104で反射された第 2の波長の光ビーム 105は、偏光ホロ グラム素子 109の第 1の回折領域 116によって図中 X方向に回折を受け、 ± 1次回 折光が第 1の受光素子群 110と第 3の受光素子群 112へと導かれ、また第 2の回折 領域 117によって図中 X方向に回折を受け、 ± 1次回折光が第 1の受光素子群 110 と第 3の受光素子群 112へと導かれる。また、上記と同様に、反射された光ビーム 10 5は、第 3の回折領域 118によって図中 X方向に回折を受け、 ± 1次回折光が第 2の 受光素子群 111と第 3の受光素子群 112へと導かれ、また第 4の回折領域 119によ つて図中 X方向に回折を受け、 ± 1次回折光が第 2の受光素子群 111と第 3の受光 素子群 112へと導かれる。  [0065] On the other hand, the light beam 105 having the second wavelength reflected by the optical information recording medium 104 is diffracted in the X direction by the first diffraction region 116 of the polarization hologram element 109, and ± 1 Is guided to the first light receiving element group 110 and the third light receiving element group 112, and is diffracted in the X direction by the second diffraction region 117, so that ± 1st order diffracted light becomes the first light receiving element group 110. To the third light receiving element group 112. Similarly to the above, the reflected light beam 105 is diffracted by the third diffraction region 118 in the X direction in the figure, and ± 1st order diffracted light is converted into the second light receiving element group 111 and the third light receiving element. Is guided to the group 112 and is diffracted in the X direction by the fourth diffraction region 119, and ± 1st order diffracted light is guided to the second light receiving element group 111 and the third light receiving element group 112. .
[0066] 第 1、第 2の受光素子群 110、 111に導力れた光ビーム 102、 105からトラッキング 誤差信号が検出され、第 3の受光素子群 112に導かれた光ビーム 102、 105からフ オーカス誤差信号が検出され、これらの検出信号を用いて第 1の光情報記録媒体 10 1もしくは第 2の光情報記録媒体 104の記録 '再生が行われる。  A tracking error signal is detected from the light beams 102 and 105 guided to the first and second light receiving element groups 110 and 111, and the light beams 102 and 105 guided to the third light receiving element group 112 are detected. A focus error signal is detected, and recording or reproduction of the first optical information recording medium 101 or the second optical information recording medium 104 is performed using these detection signals.
[0067] 次に、第 1の波長及び第 2の波長の光ビーム 102、 105からフォーカス/トラツキン グ誤差信号を検出する方法について説明する。  Next, a method for detecting a focus / tracking error signal from the light beams 102 and 105 having the first wavelength and the second wavelength will be described.
[0068] 図 4に示されるように、第 1の受光素子群 110〜第 3受光素子郡 112は Y軸方向に おいてそれぞれ複数の受光領域に分割されている。第 1の受光素子群 110は Y軸方 向 ίこおレヽて 4個の受光領域 110a、 110b, 110c, 110d こ分害され、第 2の受光素子 群 111は Y軸方向において 4個の受光領域 11 la、 111b, 111c, 11 Idに分割され 、第 3の受光素子群 112は Y軸方向において 5個の受光領域 112a、 112b, 112c, 112d, 112e こ分害 ijされてレヽる。  As shown in FIG. 4, the first light receiving element group 110 to the third light receiving element group 112 are each divided into a plurality of light receiving regions in the Y-axis direction. The first light receiving element group 110 is divided into four light receiving areas 110a, 110b, 110c, 110d in the Y-axis direction, and the second light receiving element group 111 receives four light receiving areas in the Y-axis direction. The third light receiving element group 112 is divided into five light receiving areas 112a, 112b, 112c, 112d, and 112e in the Y-axis direction, and is divided into ij, which is divided into areas 11la, 111b, 111c, and 11Id.
[0069] また、偏光ホログラム素子 109により回折された受光素子群上のビームスポットを各 受光領域 110a〜： 110d、 111a〜： l l ld、 112a〜112eにそれぞれ示した。これらの 表記において、白抜きであらわしたものは第 1の波長の光ビーム 102に起因し、黒塗 りであらわしたものは第 2の波長の光ビーム 105に起因している。 [0069] The beam spots on the light receiving element group diffracted by the polarization hologram element 109 are Light receiving regions 110a to 110d, 111a to ll ld, 112a to 112e, respectively. In these notations, the white dots are attributed to the light beam 102 of the first wavelength, and the black dots are attributed to the light beam 105 of the second wavelength.
[0070] L101c、 L104dは、第 1の波長の光ビーム 102のメインビームが偏光ホログラム素 子 109の第 1の回折領域 116により回折された回折スポットを表し、 L101a、 LlOle 、 L104b、 L104fは、第 1の波長の光ビーム 102のサブビームが偏光ホログラム素子 109の第 1の回折領域 116により回折された回折スポットを表している。  [0070] L101c and L104d represent diffraction spots in which the main beam of the light beam 102 of the first wavelength is diffracted by the first diffraction region 116 of the polarization hologram element 109, and L101a, LlOle, L104b, and L104f are A sub-beam of the light beam 102 of the first wavelength represents a diffraction spot diffracted by the first diffraction region 116 of the polarization hologram element 109.
[0071] L101d、 L104cは、第 1の波長の光ビーム 102のメインビームが偏光ホログラム素 子 109の第 2の回折領域 117により回折された回折スポットを表し、 L101b、 LlOlf 、 L104a、 L104eは、第 1の波長の光ビーム 102のサブビームが偏光ホログラム素子 109の第 2の回折領域 117により回折された回折スポットを表している。  L101d and L104c represent diffraction spots in which the main beam of the light beam 102 of the first wavelength is diffracted by the second diffraction region 117 of the polarization hologram element 109, and L101b, LlOlf, L104a, and L104e are The sub-beam of the first wavelength light beam 102 represents a diffraction spot diffracted by the second diffraction region 117 of the polarization hologram element 109.
[0072] L102d、 L103cは、第 1の波長の光ビーム 102のメインビームが偏光ホログラム素 子 109の第 3の回折領域 118により回折された回折スポットを表し、 L102b、 L102f 、 L103a、 L103eは、第 1の波長の光ビーム 102のサブビームが偏光ホログラム素子 109の第 3の回折領域 118により回折された回折スポットを表している。  [0072] L102d and L103c represent diffraction spots in which the main beam of the light beam 102 of the first wavelength is diffracted by the third diffraction region 118 of the polarization hologram element 109, and L102b, L102f, L103a, and L103e are A sub-beam of the first wavelength light beam 102 represents a diffraction spot diffracted by the third diffraction region 118 of the polarization hologram element 109.
[0073] L102c、 L103dは、第 1の波長の光ビーム 102のメインビームが偏光ホログラム素 子 109の第 4の回折領域 119により回折された回折スポットを表し、 L102a、 L102e 、 L103b、 L103fは、第 1の波長の光ビーム 102のサブビームが偏光ホログラム素子 109の第 4の回折領域 119により回折された回折スポットを表している。  [0073] L102c and L103d represent diffraction spots in which the main beam of the light beam 102 of the first wavelength is diffracted by the fourth diffraction region 119 of the polarization hologram element 109, and L102a, L102e, L103b, and L103f are A sub-beam of the first wavelength light beam 102 represents a diffraction spot diffracted by the fourth diffraction region 119 of the polarization hologram element 109.
[0074] また、 L201c、 L204dは、第 2の波長の光ビーム 105のメインビームが偏光ホログラ ム素子 109の第 1の回折領域 116により回折された回折スポットを表し、 L201a、 L2 01e、 L204b、 L204fは、第 2の波長の光ビーム 105のサブビームが偏光ホログラム 素子 109の第 1の回折領域 116により回折された回折スポットを表している。  [0074] L201c and L204d represent diffraction spots in which the main beam of the light beam 105 of the second wavelength is diffracted by the first diffraction region 116 of the polarization hologram element 109, and L201a, L201e, L204b, L204f represents a diffraction spot in which the sub beam of the light beam 105 having the second wavelength is diffracted by the first diffraction region 116 of the polarization hologram element 109.
[0075] L201d、 L204cは、第 2の波長の光ビーム 105のメインビームが偏光ホログラム素 子 109の第 2の回折領域 117により回折された回折スポットを表し、 L201b、 L201f 、 L204a、 L204eは、第 2の波長の光ビーム 105のサブビームが偏光ホログラム素子 109の第 2の回折領域 117により回折された回折スポットを表している。  L201d and L204c represent diffraction spots in which the main beam of the light beam 105 of the second wavelength is diffracted by the second diffraction region 117 of the polarization hologram element 109, and L201b, L201f, L204a, and L204e are A sub beam of the light beam 105 having the second wavelength represents a diffraction spot diffracted by the second diffraction region 117 of the polarization hologram element 109.
[0076] L202d、 L203cは、第 2の波長の光ビーム 105のメインビームが偏光ホログラム素 子 109の第 3の回折領域 118により回折された回折スポットを表し、 L202b、 L202f 、 L203c、 L203eは、第 2の波長の光ビーム 105のサブビームが偏光ホログラム素子 109の第 3の回折領域 118により回折された回折スポットを表している。 [0076] In L202d and L203c, the main beam of the light beam 105 having the second wavelength is a polarization hologram element. L202b, L202f, L203c, and L203e represent diffraction spots diffracted by the third diffraction region 118 of the optical element 109. It represents a diffracted diffraction spot.
[0077] L202c、 L203dは、第 2の波長の光ビーム 105のメインビームが偏光ホログラム素 子 109の第 4の回折領域 119により回折された回折スポットを表し、 L202a、 L202e 、 L203b、 L203fは、第 2の波長の光ビーム 105のサブビームが偏光ホログラム素子 109の第 4の回折領域 119により回折された回折スポットを表している。  L202c and L203d represent diffraction spots in which the main beam of the light beam 105 of the second wavelength is diffracted by the fourth diffraction region 119 of the polarization hologram element 109, and L202a, L202e, L203b, and L203f are A sub-beam of the second wavelength light beam 105 represents a diffraction spot diffracted by the fourth diffraction region 119 of the polarization hologram element 109.
[0078] まず、フォーカス誤差信号の検出について説明する。  First, detection of a focus error signal will be described.
[0079] 受光領域 112b、 112dからの出力信号の和を F1とし、受光領域 112a、 112c, 11 2eからの出力信号の和を F2とするとき、フォーカス誤差信号 FEは、公知の SSD (ス ポットサイズ検出）法によって検出する。第 1の波長の光ビーム 102と第 2の波長の光 ビーム 105によるフォーカス誤差信号 FE1は下記数式 2の演算によって得られる。  [0079] When the sum of output signals from the light receiving areas 112b and 112d is F1, and the sum of output signals from the light receiving areas 112a, 112c, and 112e is F2, the focus error signal FE is a known SSD (spot). Detect by size detection method. A focus error signal FE1 by the light beam 102 of the first wavelength and the light beam 105 of the second wavelength is obtained by the calculation of the following formula 2.
[0080] (数 2)  [0080] (Number 2)
F E 1 = F 1 - F 2 F E 1 = F 1-F 2
[0081] 次に、トラッキング誤差信号の検出について説明する。 Next, detection of the tracking error signal will be described.
[0082] 受光領域 110bからの出力信号を T1とし、受光領域 110cからの出力信号を T2とし 、受光領域 111cからの出力信号を T3とし、受光領域 11 lbからの出力信号を T4とし 、受光領域 110aと受光領域 110dからの出力信号の和を T5とし、受光領域 11 laと 受光領域 11 Idからの出力信号の和を T6とするとき、トラッキング誤差信号 TEは、公 知の DPD (位相差検出）法と DPP (差動プッシュプル)法によって検出する。  [0082] The output signal from the light receiving area 110b is T1, the output signal from the light receiving area 110c is T2, the output signal from the light receiving area 111c is T3, and the output signal from the light receiving area 11 lb is T4. When the sum of the output signals from 110a and the light receiving area 110d is T5, and the sum of the output signals from the light receiving area 11 la and the light receiving area 11 Id is T6, the tracking error signal TE is the known DPD (phase difference detection). ) Method and DPP (differential push-pull) method.
[0083] 第 1の波長の光ビーム 102と第 2の波長の光ビーム 105による DPD法のトラツキン グ誤差信号 TE (DPD)は下記数式 3の演算によって得られる。  [0083] The tracking error signal TE (DPD) of the DPD method using the light beam 102 of the first wavelength and the light beam 105 of the second wavelength is obtained by the calculation of Equation 3 below.
[0084] (数 3)  [0084] (Equation 3)
T E (D P D ) = (T 1と T 4の位相比較） + (T 2と T 3の位相比較）  T E (D P D) = (Phase comparison between T 1 and T 4) + (Phase comparison between T 2 and T 3)
[0085] 第 1の波長の光ビーム 102と第 2の波長の光ビーム 105による DPP法のトラッキング 誤差信号 TE (DPP)は下記数式 4の演算によって得られる。 [0086] (数 4) The tracking error signal TE (DPP) of the DPP method using the light beam 102 of the first wavelength and the light beam 105 of the second wavelength is obtained by the calculation of Equation 4 below. [0086] (number 4)
TE (D P P) = (T 1 +T 2) ― (T 3+T4) — k (T 5— T 6) TE (D P P) = (T 1 + T 2) ― (T 3 + T4) — k (T 5— T 6)
[0087] ここで、数式 4の kは任意の値とする。 [0087] Here, k in Equation 4 is an arbitrary value.
[0088] 次に、図 3を用いて波長板 108の動作について説明する。ここでは、上述した通り、 粗悪な光情報記録媒体を使用する場合を含めて説明する。  Next, the operation of the wave plate 108 will be described with reference to FIG. Here, as described above, the case where a poor optical information recording medium is used will be described.
[0089] 波長板 108はそれぞれ 2つの異なる領域 108a、 108bに分けられてレ、て、それぞ れが交互に短冊状に並ぶように配置されている。また、短冊の長手方向を X方向に 一致さている理由は、対物レンズ 115が X方向にシフトしても光ビーム 102、 105が同 じ領域を通過する様にするためである。  [0089] The wave plate 108 is divided into two different regions 108a and 108b, respectively, and is arranged so that they are alternately arranged in a strip shape. The reason why the longitudinal direction of the strip is made coincident with the X direction is that the light beams 102 and 105 pass through the same region even if the objective lens 115 is shifted in the X direction.
[0090] ここで、 2つの異なる領域 108a、 108bは、位相差がそれぞれ異なる領域である。具 体的には、波長板 108の領域 108a、 108bは光ビーム 102の波長を λΐとしたとき、 前者の位相差が λ 1/4+ aであり、後者の位相差が λ 1/4— αとなる様に設計さ れている。ここで、 αは、 一 λ 1/8く α< λ 1/8を満たす。  Here, the two different regions 108a and 108b are regions having different phase differences. Specifically, in the regions 108a and 108b of the wave plate 108, when the wavelength of the light beam 102 is λΐ, the former phase difference is λ 1/4 + a and the latter phase difference is λ 1 / 4−. It is designed to be α. Here, α satisfies 1 λ 1/8 and α <λ 1/8.
[0091] このように波長板 108が、位相差がそれぞれ異なる 2領域 108a、 108b力らなること で、粗悪な複屈折の大きい光情報記録媒体の信号が波長板 108を通過し、偏光ホロ グラム素子 109で ±1次回折光が 0にはならずに受光素子群 110、 111、 112に導か れ、安定したフォーカス誤差信号、トラッキング誤差信号を得ることが可能となる。  [0091] As described above, the wave plate 108 has the two regions 108a and 108b having different phase differences, so that the signal of the optical information recording medium having a large bad birefringence passes through the wave plate 108, and the polarization hologram The ± 1st-order diffracted light does not become zero at the element 109 but is guided to the light receiving element groups 110, 111, and 112, and stable focus error signals and tracking error signals can be obtained.
[0092] 次に、図 3の波長板 108を用いることにより、粗悪な複屈折の大きい光情報記録媒 体の信号が波長板 108を通過し、偏光ホログラム素子 109で ± 1次回折光が 0には ならずに受光素子群 110、 111、 112に導かれる理由を図 10(a)〜図 11(b)を参照 しながら説明する。  Next, by using the wave plate 108 of FIG. 3, the signal of the optical information recording medium having a large bad birefringence passes through the wave plate 108, and ± 1st order diffracted light becomes 0 by the polarization hologram element 109. First, the reason why the light receiving element groups 110, 111, and 112 are guided will be described with reference to FIGS. 10 (a) to 11 (b).
[0093] 光ビーム 102の波長を λ 1とし、光ビーム 105の波長を; 12としたとき、波長板 108 の 2つの異なる領域 108a、 108bの位相差力 それぞれ λ 1/4+ひ、 λ 1/4— a であって、 ひ = λ 1/10の条件下での、波長板 108における s偏光成分の透過率は 、図 10 (a)〜図 10(b)のようになる。図 10 (a)は、光ビーム 105の波長が; 11の時の 、光情報記録媒体の複屈折位相差の変化 (横軸）に対する、波長板 108における s偏 光成分の透過率 (縦軸）、図 10(b)は、 λ 2の時の s偏光成分の透過率を示している。 ここで、縦軸の s偏光成分の透過率は、波長板 108に円偏光が入射した場合の s偏 光の透過率を 1として表したものである。また、同図における値は、 λ 1 = 660ηιη、 λ[0093] When the wavelength of the light beam 102 is λ 1 and the wavelength of the light beam 105 is 12, the phase difference forces of two different regions 108a and 108b of the wave plate 108 are λ 1/4 + and λ 1 respectively. The transmittance of the s-polarized component in the wave plate 108 under the conditions of / 4—a and h = λ 1/10 is as shown in FIGS. 10 (a) to 10 (b). Figure 10 (a) shows the transmittance of the s-polarized component in the wave plate 108 (vertical axis) with respect to the change in birefringence phase difference of the optical information recording medium (horizontal axis) when the wavelength of the light beam 105 is 11 Figure 10 (b) shows the transmittance of the s-polarized component when λ2. Here, the transmittance of the s-polarized component on the vertical axis is the s-polarization when circularly polarized light is incident on the wave plate 108. The light transmittance is expressed as 1. The values in the figure are λ 1 = 660ηιη, λ
2 = 785nmとした場合の例である。 This is an example when 2 = 785 nm.
[0094] 図 10 (a)、図 10 (b)からわかるように、光情報記録媒体の複屈折位相差がどの様 に変化しても、波長板 108の 2つの領域 108a、 108bを通過するそれぞれの通過光 の s偏光成分の透過率が同時に 0となることはない。 As can be seen from FIGS. 10 (a) and 10 (b), no matter how the birefringence phase difference of the optical information recording medium changes, it passes through the two regions 108a and 108b of the wave plate 108. The transmittance of the s-polarized component of each passing light does not become 0 at the same time.
[0095] 従って、波長板 108を上記の様に構成することにより、粗悪な複屈折の大きい光情 報記録媒体の信号に対しても、従来に比べて安定してフォーカス誤差信号、トラツキ ング誤差信号を得ることができる。 Therefore, by configuring the wave plate 108 as described above, a focus error signal and a tracking error can be more stably compared with the conventional case even for a signal of an optical information recording medium having a large bad birefringence. A signal can be obtained.
[0096] 次に、 ひ力 _ λ ΐΖ8くひく； 1 1Z8を満たす必要性について図 11 (&)〜図11 ( b)を参照しながら説明する。 [0096] Next, the necessity of satisfying 1_Z8 will be described with reference to FIG. 11 (&) to FIG. 11 (b).
[0097] 図 11 (a)〜図 11 (b)は、図 10 (a)〜図 10 (b)の場合と同様に、波長板 108の 2領 域 108a、 108bにおける s偏光成分の透過率を示しており、図 10 (a)〜図 10 (b)と異 なる点は、 α = λ 1/8とした点である。 [0097] Figs. 11 (a) to 11 (b) show the transmittance of the s-polarized component in the two regions 108a and 108b of the wave plate 108, as in Figs. 10 (a) to 10 (b). The difference from Fig. 10 (a) to Fig. 10 (b) is that α = λ 1/8.
[0098] 同図からわかる様に、複屈折率を有する光情報記録媒体に対する上述した有効性 は図 10 (a)〜図 10 (b)の場合と同じであるが、複屈折率が 0の場合、即ち波長板 10[0098] As can be seen from the figure, the effectiveness described above for the optical information recording medium having a birefringence is the same as in the case of FIGS. 10 (a) to 10 (b), but the birefringence is 0. Case, wave plate 10
8に入射する反射光が円偏光である場合は、透過率力 より小さな値となる。これは、 すでに説明した通り、図 3の波長板 108の 2領域では、 λ 1/4に対してわざと土ひの ズレを生じさせた構造だからである。 When the reflected light incident on 8 is circularly polarized light, the value is smaller than the transmittance power. This is because, as already explained, the two regions of the wave plate 108 in FIG.
[0099] 従って、複屈折率が 0である光情報記録媒体を使用する場合に、 ぇ1について、従 来と同等レベルの安定した制御を維持するためには、 s偏光の透過率が 0. 85以下 にならない様に αを制限する必要がある。 [0099] Therefore, when using an optical information recording medium having a birefringence of 0, in order to maintain stable control at the same level as in the case of E1, the transmittance of s-polarized light is 0. It is necessary to limit α so that it is not less than 85.
[0100] そこで、製造ばらつき等をも考慮して、 ひの範囲を一 λ 1/8く α < λ 1/8を満た すものと規定した。 [0100] Therefore, in consideration of manufacturing variability and the like, it was defined that the range of the string satisfies one λ 1/8 and α <λ 1/8.
[0101] 尚、上記条件とは別の例として、 2領域の一方の位相差を λ 1Ζ4とし、他方の位相 差を _ 3 Χ λ ΐΖ4 (これの逆も可能である）となるように構成されていても良レ、。この 場合にっレ、て、図 12 (a)〜図 12 (b)を用いて説明する。  [0101] In addition, as an example different from the above condition, the configuration is such that one phase difference of two regions is λ 1 Ζ4 and the other phase difference is _ 3 Χ λ ΐΖ4 (the reverse is also possible) Even if it is done, it is good. This case will be described with reference to FIGS. 12 (a) to 12 (b).
[0102] 光ビーム 102、 103のそれぞれの波長が λ 1、 λ 2であり、波長板 108のそれぞれ の 2つの異なる領域 108a、 108b力 S、 λ 1/4、 - 3 Χ λ lZ4のとき、波長板 108に おける s偏光成分の透過率は図 12 (a)〜図 12 (b)のようになる。 [0102] When the wavelengths of the light beams 102 and 103 are λ 1 and λ 2 and the two different regions 108a, 108b of each wave plate 108, 108b force S, λ 1/4,-3 λ λ lZ4, On wave plate 108 The transmittance of the s-polarized component is as shown in Fig. 12 (a) to Fig. 12 (b).
[0103] 図 12 (a)は、 ぇ1の時の透過率、図 12 (b)は、 λ 2の時の透過率を示している。図 1 2 (a)からわかるように、 λ 1の時は光情報記録媒体の複屈折位相差が変化した場合 (図 12 (a)では、複屈折位相差が 1のとき）、波長板 108の 2つの領域 108a、 108bを 通過するそれぞれの通過光の s偏光成分の透過率が同時に 0になってしまう。しかし 、図 12 (b)の; I 2の時は光情報記録媒体の複屈折位相差がどのように変化しても、 波長板 108の 2つの領域 108a、 108bにおレ、て、同時に透過率が 0になることはない [0103] Fig. 12 (a) shows the transmittance at the time of 1, and Fig. 12 (b) shows the transmittance at the time of λ2. As can be seen from Fig. 1 2 (a), when the birefringence phase difference of the optical information recording medium changes at λ 1 (in Fig. 12 (a), the birefringence phase difference is 1), the wave plate 108 The transmittance of the s-polarized component of each passing light passing through the two regions 108a and 108b simultaneously becomes zero. However, in FIG. 12 (b); I 2, no matter how the birefringence phase difference of the optical information recording medium changes, the two regions 108a and 108b of the wave plate 108 are transmitted simultaneously. The rate will never be 0
[0104] 従って、このような構成では、 λ 2の時、粗悪な複屈折の大きい光情報記録媒体の 信号に対しても安定してフォーカス誤差信号、トラッキング誤差信号を得ることができ る。 Therefore, in such a configuration, when λ 2, it is possible to stably obtain a focus error signal and a tracking error signal even for a signal of an optical information recording medium having a large bad birefringence.
[0105] 本実施の形態によれば、 2つの異なる半導体レーザを用いることで、第 1の波長の 光ビーム 102、第 2の波長の光ビーム 105により異なる各種光情報記録媒体 101、 1 04への対応が可能である。それと共に、第 1の波長の光ビーム 102、第 2の波長の光 ビーム 105を共通の受光素子群でフォーカス及びトラッキング誤差信号を検出し、フ オーカス誤差信号の検出処理のための信号系と、トラッキング誤差信号の検出処理 のための信号系とを完全に分離することができ、信号処理システムを簡素化できる。 さらに、本実施の形態によれば、複屈折の大きい粗悪な光情報記録媒体に対しても 、安定した記録'再生を実現するフォーカス及びトラッキング誤差信号の検出が可能 となる。  According to the present embodiment, by using two different semiconductor lasers, various types of optical information recording media 101 and 104 differ depending on the light beam 102 having the first wavelength and the light beam 105 having the second wavelength. Is possible. At the same time, a focus and tracking error signal is detected by a common light receiving element group for the first wavelength light beam 102 and the second wavelength light beam 105, and a signal system for detecting a focus error signal; The signal system for tracking error signal detection processing can be completely separated, and the signal processing system can be simplified. Furthermore, according to the present embodiment, it is possible to detect a focus and tracking error signal that realizes stable recording and reproduction even for a poor optical information recording medium having a large birefringence.
[0106] (実施の形態 2)  [Embodiment 2]
図 5は、本発明の実施の形態 2における光ピックアップ装置の構成を模式的に示し ている。  FIG. 5 schematically shows the configuration of the optical pickup device according to the second embodiment of the present invention.
[0107] 図 5に示した構成は、基本的には実施の形態 1に示したものと同様であり、違いは 回折格子 107がガラスまたは樹脂状の回折格子板 201で形成され、第 1の半導体レ 一ザ 103と第 2の半導体レーザ 106と第 1の受光素子群 110と第 2の受光素子群 11 1と第 3の受光素子群 112を集積した集積回路基板 113を一つのパッケージ 202に 搭載し、回折格子板 201とパッケージ 202が一体化している点である。 [0108] 本実施の形態の光ピックアップ装置の動作、フォーカス誤差信号の検出、トラツキン グ誤差信号の検出、波長板 108の動作については、実施の形態 1と同様である。 The configuration shown in FIG. 5 is basically the same as that shown in Embodiment 1, except that diffraction grating 107 is formed of glass or resin-like diffraction grating plate 201, and the first An integrated circuit board 113 in which a semiconductor laser 103, a second semiconductor laser 106, a first light receiving element group 110, a second light receiving element group 111, and a third light receiving element group 112 are integrated into one package 202. In other words, the diffraction grating plate 201 and the package 202 are integrated. The operation of the optical pickup device of the present embodiment, the detection of the focus error signal, the detection of the tracking error signal, and the operation of the wave plate 108 are the same as in the first embodiment.
[0109] 本実施の形態によれば、回折格子板 201とパッケージ 202を一体化することで、記 録-再生装置において小型化 ·簡素化 ·低コスト化が実現することができ、また、回折 格子板 201とパッケージ 202を一体化することで、取り扱う部品点数を削減でき、組 み立てを行うための精度向上を可能とすることができる。  [0109] According to the present embodiment, by integrating the diffraction grating plate 201 and the package 202, it is possible to achieve downsizing, simplification, and cost reduction in the recording / reproducing apparatus. By integrating the lattice plate 201 and the package 202, it is possible to reduce the number of parts to be handled and improve the accuracy for assembling.
[0110] (実施の形態 3)  [0110] (Embodiment 3)
図 6は、本発明の実施の形態 3における光ピックアップ装置の構成を模式的に示し ている。  FIG. 6 schematically shows the configuration of the optical pickup device according to the third embodiment of the present invention.
[0111] 図 6に示した構成は、基本的には実施の形態 1に示したものと同様であり、違いは 第 1の半導体レーザ 103と第 2の半導体レーザ 106を一体化したモノリツシック 2波長 半導体レーザ 301で形成されている点である。  [0111] The configuration shown in FIG. 6 is basically the same as that shown in Embodiment 1, with the difference being the monolithic two-wavelength in which the first semiconductor laser 103 and the second semiconductor laser 106 are integrated. This is a point formed by the semiconductor laser 301.
[0112] 本実施の形態の光ピックアップ装置の動作、フォーカス誤差信号の検出、トラツキン グ誤差信号の検出、波長板 108の動作については、実施の形態 1と同様である。  The operation of the optical pickup device of the present embodiment, the detection of the focus error signal, the detection of the tracking error signal, and the operation of the wave plate 108 are the same as in the first embodiment.
[0113] 本実施の形態によれば、第 1の半導体レーザ 103と第 2の半導体レーザ 106を 1つ のモノリツシック 2波長半導体レーザ 301とすることで、第 1の半導体レーザ 103と第 2 の半導体レーザ 106の光ビーム出射間隔は組み立て精度で決まる力 モノリツシック 2波長半導体レーザ 301の光ビーム出射間隔は拡散精度で決まる。このことから、モ ノリツシック 2波長半導体レーザ 301の光ビーム出射間隔の方が精度良くすることが できる。  [0113] According to the present embodiment, the first semiconductor laser 103 and the second semiconductor laser 106 are formed as one monolithic two-wavelength semiconductor laser 301, whereby the first semiconductor laser 103 and the second semiconductor laser 103 are combined. The light beam emission interval of the laser 106 is determined by the assembly accuracy. Monolithic The light beam emission interval of the two-wavelength semiconductor laser 301 is determined by the diffusion accuracy. From this, the light beam emission interval of the monolithic two-wavelength semiconductor laser 301 can be made more accurate.
[0114] また、実施の形態 1、実施の形態 2についてもモノリツシック 2波長半導体レーザ 30 [0114] The first and second embodiments are also monolithic two-wavelength semiconductor lasers 30.
1を適用することは可能である。 It is possible to apply one.
[0115] (実施の形態 4) [0115] (Embodiment 4)
次に、本発明の実施の形態 4における光ピックアップ装置について説明する。  Next, an optical pickup device according to Embodiment 4 of the present invention will be described.
[0116] 実施の形態 4における光ピックアップ装置の構成は、基本的には、実施の形態 1に おける光ピックアップ装置の構成と同じであるが、本発明の実施の形態 4における回 折格子 107の構造は、次に示す点において実施の形態 1で用いた一般的な回折格 子とは異なる。 [0117] 図 7は、実施の形態 4における光ピックアップ装置の回折格子 107の平面図である 。回折格子 107には第 1の回折領域 401と第 2の回折領域 402から形成されている。 第 1の波長の光ビーム 102を回折格子 107の第 1の回折領域 401で 0次回折光のメ インビーム 102Mに回折し、回折格子 107の第 2の回折領域 402で + 1次回折光の サブビーム 102S1と _ 1次回折光のサブビーム 102S2に回折する。第 2波長の光ビ ーム 105を回折格子 107の第 1の回折領域 501で 0次回折光のメインビーム 105M に回折し、回折格子 107の第 2の回折領域 402で + 1次回折光のサブビーム 105S1 と一 1次回折光のサブビーム 105S2に回折する。 The configuration of the optical pickup device in the fourth embodiment is basically the same as the configuration of the optical pickup device in the first embodiment, but the configuration of the diffraction grating 107 in the fourth embodiment of the present invention is the same as that of the first embodiment. The structure is different from the general diffraction grating used in Embodiment 1 in the following points. FIG. 7 is a plan view of diffraction grating 107 of the optical pickup device in the fourth embodiment. The diffraction grating 107 is formed of a first diffraction region 401 and a second diffraction region 402. The first wavelength light beam 102 is diffracted by the first diffraction region 401 of the diffraction grating 107 into the 0th-order diffracted main beam 102M, and the second diffraction region 402 of the diffraction grating 107 + the first-order diffracted light sub-beam 102S1 And _ Diffracted into sub-beam 102S2 of 1st-order diffracted light. The second-wavelength light beam 105 is diffracted into the 0th-order diffracted light main beam 105M in the first diffraction region 501 of the diffraction grating 107, and the first-order diffracted light sub-beam 105S1 in the second diffraction region 402 of the diffraction grating 107. And diffracted into the first-order diffracted light sub-beam 105S2.
[0118] 異なる各種光情報記録媒体の記録 ·再生の効率を上げるためにはメインビームの 強度を上げる必要がある。メインビームの強度を上げるためには、第 1の回折領域 40 1における 0次回折光の回折効率を 100%とすることが最も望ましい。第 1の回折領 域 401における 0次回折光の回折効率を 100%とすることは、結局、第 1の回折領域 401が形成された領域には格子を形成しないこと、すなわち無格子領域を設けること と等価である。  [0118] In order to increase the recording / reproducing efficiency of various optical information recording media, it is necessary to increase the intensity of the main beam. In order to increase the intensity of the main beam, it is most desirable to set the diffraction efficiency of the 0th-order diffracted light in the first diffraction region 401 to 100%. Setting the diffraction efficiency of the 0th-order diffracted light in the first diffraction region 401 to 100% means that no grating is formed in the region where the first diffraction region 401 is formed, that is, a non-lattice region is provided. Is equivalent to
[0119] また、回折格子 107の第 2の回折領域 402は第 1の波長の光ビーム 102の ± 1次回 折光のサブビーム 102S1、 102S2と第 2の波長の光ビーム 105の ± 1次回折光のサ ブビーム 105S1、 105S2の効率が最大に成るように第 2の回折領域 402の格子深さ を決めている。  [0119] The second diffraction region 402 of the diffraction grating 107 includes ± 1 sub-beams 102S1 and 102S2 of the first-fold light 102 and the first-wavelength light beam 105 of the first wavelength. The grating depth of the second diffraction region 402 is determined so that the efficiency of the sub beams 105S1 and 105S2 is maximized.
[0120] 本実施の形態によれば、回折格子の第 1の回折領域 401を無格子領域で形成す ることにより、メインビームの強度を最大限に高めることが可能である。し力も、第 1の 回折領域 401は無格子領域のため、 ± 1次回折光のサブビームは発生しない。また 、第 2の回折領域 402は ± 1次回折光のサブビームを最大限に高めることが可能で ある。従って、光ピックアップ装置自体の光利用効率 (メインビーム、サブビーム）を最 大限に高めることが可能である。  [0120] According to the present embodiment, it is possible to maximize the intensity of the main beam by forming the first diffraction region 401 of the diffraction grating as a non-lattice region. However, since the first diffraction region 401 is a non-lattice region, a ± first-order diffracted light sub-beam is not generated. In addition, the second diffraction region 402 can maximize the sub beam of ± 1st order diffracted light. Therefore, it is possible to maximize the light use efficiency (main beam, sub beam) of the optical pickup device itself.
[0121] また、光情報記録媒体のピット上でのビームスポットの位置調整工程を簡素化する ためには、図 8に示す回折格子 1070を用いても良レ、。図 8に示す回折格子 1070で は、図 7に示した回折格子 107の第 2の回折領域 402の格子が、帯状に形成された 第 1の回折領域 401に対して所定角度だけ傾斜して形成されている。 [0122] 上記回折格子 1070により、ビームスポットの位置調整工程を簡素化できる理由に ついて説明する。 [0121] Further, in order to simplify the process of adjusting the position of the beam spot on the pit of the optical information recording medium, the diffraction grating 1070 shown in Fig. 8 may be used. In the diffraction grating 1070 shown in FIG. 8, the grating of the second diffraction region 402 of the diffraction grating 107 shown in FIG. 7 is formed so as to be inclined by a predetermined angle with respect to the first diffraction region 401 formed in a band shape. Has been. The reason why the beam spot position adjusting process can be simplified by the diffraction grating 1070 will be described.
[0123] 即ち、光情報記録媒体のグノレーブ部分にメインビームを配置し、ランド部分にサブ ビームを配置する必要がある。そのため、図 7に示す回折格子 107を配置する場合、 光情報記録媒体のグループ部分にメインビームが配置され、ランド部分にサブビー ムが配置される様に、回折格子 107自体を所定角度だけ回転させるという調整工程 が必要となる。  That is, it is necessary to arrange the main beam in the gnoll part of the optical information recording medium and arrange the sub beam in the land part. Therefore, when the diffraction grating 107 shown in FIG. 7 is arranged, the diffraction grating 107 itself is rotated by a predetermined angle so that the main beam is arranged in the group portion of the optical information recording medium and the sub beam is arranged in the land portion. This adjustment process is required.
[0124] これに対して、図 8に示す回折格子 1070では、予め、第 2の回折領域 402の格子 が、帯状に形成された第 1の回折領域 401に対して所定角度だけ傾斜して形成され ている。そのため、回折格子 1070自体を所定角度だけ回転させるという調整工程は 不要となり、位置調整工程は全体として簡素化できる。  On the other hand, in the diffraction grating 1070 shown in FIG. 8, the grating of the second diffraction region 402 is formed in advance with a predetermined angle with respect to the first diffraction region 401 formed in a band shape. It has been. Therefore, the adjustment process of rotating the diffraction grating 1070 itself by a predetermined angle becomes unnecessary, and the position adjustment process can be simplified as a whole.
[0125] また、実施の形態 4における回折格子を実施の形態 1、実施の形態 2、実施の形態 3に利用することも可能である。  In addition, the diffraction grating according to the fourth embodiment can be used in the first embodiment, the second embodiment, and the third embodiment.
[0126] (実施の形態 5)  [Embodiment 5]
次に、本発明の実施の形態 5における光ピックアップ装置について説明する。  Next, an optical pickup device according to Embodiment 5 of the present invention will be described.
[0127] 実施の形態 5における光ピックアップ装置の構成は、基本的には、実施の形態 1に おける光ピックアップ装置の構成と同じであるが、本発明の実施の形態 5における集 積回路基板 113の構造は、次に示す点において実施の形態 1のものとは異なる。  The configuration of the optical pickup device in the fifth embodiment is basically the same as the configuration of the optical pickup device in the first embodiment, but the integrated circuit board 113 in the fifth embodiment of the present invention. This structure differs from that of the first embodiment in the following points.
[0128] 図 9は、実施の形態 5における光ピックアップ装置の集積回路基板 113の等価回路 図である。  FIG. 9 is an equivalent circuit diagram of the integrated circuit board 113 of the optical pickup device in the fifth embodiment.
[0129] 受光領域 110bからの出力信号を電流電圧変換増幅回路 501で変換増幅した後 T 1を出力し、受光領域 110cからの出力信号を電流電圧変換増幅回路 502で変換増 幅後 T2を出力し、受光領域 111cからの出力信号を電流電圧変換増幅回路 503で 変換増幅後 T3を出力し、受光領域 111bからの出力信号を電流電圧変換増幅回路 504で変換増幅後 T4を出力する。  [0129] The output signal from the light receiving area 110b is converted and amplified by the current-voltage conversion amplifier circuit 501, and then T 1 is output. The output signal from the light receiving area 110c is output by the current-voltage conversion amplifier circuit 502 and output after T2 is output. Then, the output signal from the light receiving region 111c is converted and amplified by the current / voltage conversion amplifier circuit 503, and T3 is output. The output signal from the light receiving region 111b is converted and amplified by the current / voltage conversion amplifier circuit 504, and T4 is output.
[0130] 一方、受光領域 110aと受光領域 110dからの出力信号の和を電流電圧変換増幅 回路 505で変換増幅後 T5を出力し、受光領域 111aと受光領域 l l ldからの出力信 号の和を電流電圧変換増幅回路 506で変換増幅後 T6を出力する。さらに、受光領 域 112b、 112dからの出力信号の和を電流電圧変換増幅回路 507で変換増幅後 F 1を出力し、受光領域 112a、 112c, 112eからの出力信号の和を電流電圧変換増幅 回路 508で変換増幅後 F2を出力する。これによつて実施の形態 5における各出力信 号は電圧出力信号となる。 [0130] On the other hand, the sum of the output signals from light receiving area 110a and light receiving area 110d is converted and amplified by current-voltage conversion amplification circuit 505, and then T5 is output. The sum of the output signals from light receiving area 111a and light receiving area ll ld is calculated. Current-voltage conversion amplifier circuit 506 outputs T6 after conversion amplification. In addition, the light receiving area The sum of the output signals from the areas 112b and 112d is converted and amplified by the current-voltage conversion amplifier circuit 507, and then F 1 is output. The sum of the output signals from the light-receiving areas 112a, 112c, and 112e is converted and amplified by the current-voltage conversion amplifier circuit 508. After output F2. As a result, each output signal in the fifth embodiment becomes a voltage output signal.
[0131] 本実施の形態によれば、各信号出力 Tl、 Τ2、 Τ3、 Τ4、 Τ5、 Τ6、 Fl、 F2を電流 電圧変換増幅回路によって、電圧出力信号とすることで電流出力信号より外的信号 ノイズに強くなり、電流電圧変換増幅回路を集積回路基板上に実装することで記録' 再生速度を向上することが可能である。  [0131] According to the present embodiment, each signal output Tl, Τ2, Τ3, Τ4, Τ5, Τ6, Fl, F2 is converted into a voltage output signal by a current-voltage conversion amplifier circuit, so that it is external to the current output signal. It becomes resistant to signal noise, and the recording / reproducing speed can be improved by mounting the current-voltage conversion amplifier circuit on the integrated circuit board.
[0132] また、実施の形態 5における集積回路基板を実施形態 1、実施の形態 2、実施の形 態 3、実施の形態 4に利用することも可能である。  [0132] The integrated circuit board according to the fifth embodiment can be used in the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment.
[0133] また、実施の形態 1から 5において、例えば、第 1の光情報記録媒体は DVD (DVD 、 DVD-ROM, DVD -RAM, DVD-R, DVD— RW等）であり、第 2の光情報記 録媒体は CD (CD、 CD-ROM, CD-R, CD— RW等）であり、第 1の波長は約 65 Onmであり、第 2の波長は約 780nmである。  In Embodiments 1 to 5, for example, the first optical information recording medium is a DVD (DVD, DVD-ROM, DVD-RAM, DVD-R, DVD-RW, etc.), and the second The optical information recording medium is a CD (CD, CD-ROM, CD-R, CD-RW, etc.), the first wavelength is about 65 Onm, and the second wavelength is about 780 nm.
[0134] 尚、上記実施の形態では、偏光ホログラム素子 109は、 2波長に対して 1枚で構成 した場合に付いて説明した。し力 これに限らず、偏光ホログラム素子 109は、例え ば、従来の様に、各波長毎に別々に構成しても良い。その場合、偏光ホログラム素子 109の距離 Lにつレ、て、数式 1に規定される範囲に制限されることは無レ、。  [0134] In the above embodiment, the description has been given of the case where the polarization hologram element 109 is composed of one for two wavelengths. However, the present invention is not limited to this, and the polarization hologram element 109 may be configured separately for each wavelength, for example, as in the prior art. In that case, there is no limit to the range defined by Equation 1 for the distance L of the polarization hologram element 109.
[0135] また、上記実施の形態では、波長板 108と偏光ホログラム素子 109とを一体に形成 した場合について説明したが、これに限らず例えば別体でも良い。  [0135] In the above-described embodiment, the case where the wave plate 108 and the polarization hologram element 109 are integrally formed has been described. However, the present invention is not limited to this.
[0136] また、上記実施の形態では、波長板 108は、偏光ホログラム素子 109とコリメ一タレ ンズ 114と間に配置された場合について説明した。し力 これに限らず、波長板 108 は、例えば、対物レンズ 115とコリメータレンズ 114の間に配置されていても良レ、（図 1 3 (a) ,図 13 (b)参照）。  [0136] In the above embodiment, the case where the wave plate 108 is disposed between the polarization hologram element 109 and the collimator lens 114 has been described. However, the wave plate 108 may be disposed between the objective lens 115 and the collimator lens 114, for example (see FIGS. 13 (a) and 13 (b)).
[0137] 上述した光ピックアップ装置によれば、使用する半導体レーザ光の波長がそれぞれ 異なる各種光情報記録媒体への対応が可能であると共に、部品点数を減らし、より 簡素に構成でき、より安定した記録 ·再生を実現するフォーカス、及びトラッキング誤 差信号の検出を可能とするものである。 [0138] 即ち、本発明に力かる光ピックアップ装置は、 2つの異なる半導体レーザを用いるこ とで、異なる各種光情報記録媒体への対応が可能であると共に、より安定した記録 · 再生を実現するフォーカス、及びトラッキング誤差信号の検出を行うことができる。そ のため、 DVD系、 CD系の記録 '再生装置において小型化 ·簡素化 ·低コスト化'高 効率化を実現することができる。 [0137] According to the optical pickup device described above, it is possible to cope with various optical information recording media having different wavelengths of semiconductor laser light to be used, reduce the number of parts, and can be configured more simply and more stably. This enables detection of focus and tracking error signals that realize recording and playback. That is, the optical pickup device according to the present invention can be applied to various optical information recording media and can realize more stable recording / reproduction by using two different semiconductor lasers. The focus and tracking error signals can be detected. As a result, DVD- and CD-based recording 'reproduction devices can be made smaller, simpler, and less costly' and more efficient.
[0139] 従って、本発明の光ピックアップ装置は、光ディスクなどの光情報記録媒体に、情報 の記録、再生、消去などの処理を行う光学式情報処理装置の分野において、その基 幹部品である光学式ヘッド装置に使用される再生及び Z又は記録信号及び各種サ ーボ信号の検出機能を有する光ピックアップ装置として有用である。  Therefore, the optical pickup device of the present invention is an optical component that is a key component in the field of optical information processing devices that perform processing such as information recording, reproduction, and erasing on an optical information recording medium such as an optical disk. It is useful as an optical pickup device having a function of detecting reproduction and Z or recording signals and various servo signals used in the head type device.
産業上の利用可能性  Industrial applicability
[0140] 本発明にかかる光ピックアップ装置は、使用する半導体レーザ光の波長がそれぞ れ異なる各種光情報記録媒体への対応が可能であると共に、フォーカス誤差信号と トラッキング誤差信号をより安定して検出することが可能となるという効果を有し、光ピ ックアップ装置等として有用である。 [0140] The optical pickup device according to the present invention can cope with various optical information recording media in which the wavelengths of the semiconductor laser light to be used are different, and more stably the focus error signal and the tracking error signal. It has an effect that it can be detected, and is useful as an optical pickup device or the like.

Claims

請求の範囲 The scope of the claims
[1] 第 1の波長の光ビームを出射する第 1の半導体レーザと、  [1] a first semiconductor laser emitting a light beam of a first wavelength;
前記第 1の半導体レーザより波長の長い第 2の波長の光ビームを出射する第 2の半 導体レーザと、  A second semiconductor laser that emits a light beam having a second wavelength longer than that of the first semiconductor laser;
前記第 1の波長の光ビームまたは前記第 2の波長の光ビームをそれぞれ異なる次 数の回折光に回折するための回折格子と、  A diffraction grating for diffracting the light beam of the first wavelength or the light beam of the second wavelength into diffracted lights of different orders;
前記回折格子により回折された回折光を平行ビームにするためのコリメータレンズと 前記平行ビームを光情報記録媒体の記録面に集光させるための対物レンズと、 前記光情報記録媒体の記録面により反射された戻り光を回折する偏光ホログラム 素子と、  A collimator lens for converting the diffracted light diffracted by the diffraction grating into a parallel beam; an objective lens for condensing the parallel beam on a recording surface of the optical information recording medium; and reflecting by the recording surface of the optical information recording medium A polarization hologram element that diffracts the reflected return light,
位相に関する特性が異なる領域が短冊状に交互に配置された波長板と、 前記偏光ホログラム素子により回折された回折光を受光する複数の受光素子と、 を備えた光ピックアップ装置。  An optical pickup device comprising: a wave plate in which regions having different phase-related characteristics are alternately arranged in a strip shape; and a plurality of light receiving elements that receive diffracted light diffracted by the polarization hologram element.
[2] 前記回折格子は、前記光ビームをそれぞれ 0次回折光と ± 1次回折光に回折する[2] The diffraction grating diffracts the light beam into 0th order diffracted light and ± 1st order diffracted light, respectively.
、請求の範囲第 1項記載の光ピックアップ装置。 The optical pickup device according to claim 1.
[3] 前記波長板は、 2つの異なる特性の前記領域が短冊状に交互に配置された波長 板であり、 [3] The wave plate is a wave plate in which the regions having two different characteristics are alternately arranged in a strip shape,
前記第 1の波長の光ビームの波長を λ 1とするとき、前記 2つの異なる特性の一方 の特性の領域の位相差が λ 1/4 + aであり、他方の特性の領域の位相差が λ 1/ 4一ひであり、且つ前記ひが _ λ 1/8く α < λ 1/8である、請求の範囲第 1項また は第 2項記載の光ピックアップ装置。  When the wavelength of the light beam of the first wavelength is λ1, the phase difference of one of the two different characteristics is λ 1/4 + a, and the phase difference of the other characteristic is The optical pickup device according to claim 1 or 2, wherein λ 1/4 is one and the string is _ λ 1/8 and α <λ 1/8.
[4] 前記波長板は、 2つの異なる特性の前記領域が短冊状に交互に配置された波長 板であり、 [4] The wave plate is a wave plate in which the regions having two different characteristics are alternately arranged in a strip shape,
前記第 1の波長の光ビームの波長を λ 1とするとき、前記 2つの異なる特性の一方 の特性の領域の位相差がえ 1/4であり、他方の特性の領域の位相差が 3 X λ 1 /4である、請求の範囲第 1項または第 2項記載の光ピックアップ装置。  When the wavelength of the light beam of the first wavelength is λ1, the phase difference of one of the two different characteristics is 1/4, and the phase difference of the other characteristic is 3 × 3. The optical pickup device according to claim 1, wherein λ 1/4.
[5] 前記波長板は、前記対物レンズと前記コリメータレンズの間に設けられている、請求 の範囲第 1項記載の光ピックアップ装置。 [5] The wave plate is provided between the objective lens and the collimator lens. 2. An optical pickup device as set forth in claim 1.
[6] 前記偏光ホログラム素子は、前記回折格子と前記コリメータレンズの間に設けられ ている、請求の範囲第 1項記載の光ピックアップ装置。  6. The optical pickup device according to claim 1, wherein the polarization hologram element is provided between the diffraction grating and the collimator lens.
[7] 前記波長板と前記偏光ホログラム素子とがー体的に構成されている、請求の範囲 第 1項記載の光ピックアップ装置。  7. The optical pickup device according to claim 1, wherein the wavelength plate and the polarization hologram element are configured in a body.
[8] 前記対物レンズの焦点距離を fl、前記コリメータレンズの焦点距離を f 2、光学倍率 を β ( = f2/fl)、前記第 1の半導体レーザの発光点と前記第 2の半導体レーザの発 光点間隔を a、前記第 1の波長のビームによる前記対物レンズの開口数を NA1、前 記第 2の波長のビームによる前記対物レンズの開口数を NA2、 (NA1 >NA2とする )、前記第 1の半導体レーザの発光点から前記偏光ホログラム素子までの距離をしと したとき、  [8] The focal length of the objective lens is fl, the focal length of the collimator lens is f2, the optical magnification is β (= f2 / fl), the emission point of the first semiconductor laser and the second semiconductor laser The emission point interval is a, the numerical aperture of the objective lens by the beam of the first wavelength is NA1, the numerical aperture of the objective lens by the beam of the second wavelength is NA2, (NA1> NA2), When the distance from the emission point of the first semiconductor laser to the polarization hologram element is taken,
[数 1] a X j3 / ( N A 2 - 0 . 6 7 X N A 1 ) ≤ L < f 2 を満たす距離 Lの位置に前記偏光ホログラム素子が配置されている、請求の範囲第 [Expression 1] The polarization hologram element is disposed at a position of a distance L that satisfies a X j3 / (NA 2-0.67 XNA1) ≤ L <f2.
6項または第 7項記載の光ピックアップ装置。 8. The optical pickup device according to item 6 or 7.
[9] 前記偏光ホログラム素子は、 4領域に分割されており、且つそれぞれの前記領域に おいて 2つの異なる回折特性を持つ領域が短冊状に交互に配置されている、請求の 範囲第 1項記載の光ピックアップ装置。 [9] The polarization hologram element according to claim 1, wherein the polarization hologram element is divided into four regions, and regions having two different diffraction characteristics are alternately arranged in a strip shape in each of the regions. The optical pickup device described.
[10] 前記第 1の半導体レーザの光軸と、前記偏光ホログラム素子の前記 4領域の中心と 力 前記コリメータレンズの光軸中心と実質上一致している、請求の範囲第 9項記載 の光ピックアップ装置。 10. The light according to claim 9, wherein the optical axis of the first semiconductor laser, the center of the four regions of the polarization hologram element, and the force substantially coincide with the optical axis center of the collimator lens. Pickup device.
[11] 前記受光素子は、前記第 1の半導体レーザおよび前記第 2の半導体レーザの両側 に前記第 1の半導体レーザおよび前記第 2の半導体レーザと離間して、かつ前記第 1の半導体レーザにおける光出射位置と前記第 2の半導体レーザにおける光出射位 置とを結ぶ延長線上に配置されており、  [11] The light receiving element is separated from the first semiconductor laser and the second semiconductor laser on both sides of the first semiconductor laser and the second semiconductor laser, and in the first semiconductor laser. Arranged on an extension line connecting the light emitting position and the light emitting position in the second semiconductor laser,
前記第 1の半導体レーザ力 見て前記第 2の半導体レーザの反対側に配置された 前記受光素子数が、前記第 2の半導体レーザから見て前記第 1の半導体レーザの反 対側に配置された前記受光素子数よりも少ない、請求の範囲第 1項記載の光ピック アップ装置。 The number of light receiving elements arranged on the opposite side of the second semiconductor laser with respect to the first semiconductor laser force is the reaction of the first semiconductor laser with respect to the second semiconductor laser. 2. The optical pickup device according to claim 1, wherein the number is smaller than the number of the light receiving elements arranged on the opposite side.
[12] 前記光情報記録媒体の記録面から反射された前記第 1の波長の光ビーム、又は前 記第 2の波長の光ビームは、前記偏光ホログラム素子により回折され、回折光を共通 の受光素子で受光する、請求の範囲第 1項記載の光ピックアップ装置。  [12] The light beam of the first wavelength reflected from the recording surface of the optical information recording medium or the light beam of the second wavelength is diffracted by the polarization hologram element, and the diffracted light is received in common. 2. The optical pickup device according to claim 1, which receives light by an element.
[13] 前記受光素子からの信号に基づレ、てフォーカス及びトラッキング誤差信号を得る、 請求の範囲第 12項記載の光ピックアップ装置。  13. The optical pickup device according to claim 12, wherein a focus and tracking error signal is obtained based on a signal from the light receiving element.
[14] 前記第 1の半導体レーザから見て前記第 2の半導体レーザの反対側に配置された 前記受光素子でフォーカス誤差信号を得、前記第 2の半導体レーザから見て前記第 1の半導体レーザの反対側に配置された前記受光素子でトラッキング誤差信号を得 る、請求の範囲第 13項記載の光ピックアップ装置。  [14] A focus error signal is obtained by the light receiving element disposed on the opposite side of the second semiconductor laser as viewed from the first semiconductor laser, and the first semiconductor laser as viewed from the second semiconductor laser. 14. The optical pickup device according to claim 13, wherein a tracking error signal is obtained by the light receiving element arranged on the opposite side of the optical pickup.
[15] 前記第 1の半導体レーザと前記第 2の半導体レーザと前記複数の受光素子とが、 同一の集積回路基板上に搭載されている、請求の範囲第 1項記載の光ピックアップ 装置。  15. The optical pickup device according to claim 1, wherein the first semiconductor laser, the second semiconductor laser, and the plurality of light receiving elements are mounted on the same integrated circuit substrate.
[16] 前記集積回路基板上に、 2つのフォーカス誤差信号用電流電圧変換増幅回路と、 [16] On the integrated circuit substrate, two current-voltage conversion amplifier circuits for focus error signals;
6つのトラッキング誤差信号用電流電圧変換増幅回路が搭載されている、請求の範 囲第 15項記載の光ピックアップ装置。 16. The optical pickup device according to claim 15, wherein six tracking error signal current-voltage conversion amplifier circuits are mounted.
[17] 前記集積回路基板と前記回折格子とが、 1つのパッケージに搭載されている、請求 の範囲第 15項記載の光ピックアップ装置。 17. The optical pickup device according to claim 15, wherein the integrated circuit board and the diffraction grating are mounted in one package.
[18] 前記第 1の半導体レーザと前記第 2の半導体レーザとが、 1つのモノリツシック半導 体レーザで構成されている、請求の範囲第 1項記載の光ピックアップ装置。 18. The optical pickup device according to claim 1, wherein the first semiconductor laser and the second semiconductor laser are constituted by one monolithic semiconductor laser.
[19] 前記回折格子は、互いに回折効率の異なる第 1の回折領域および第 2の回折領域 を有し、  [19] The diffraction grating has a first diffraction region and a second diffraction region having different diffraction efficiencies,
前記第 1の回折領域における 0次回折光の回折効率は、前記第 2の回折領域にお ける 0次回折光の回折効率よりも大きぐ  The diffraction efficiency of the 0th order diffracted light in the first diffraction region is larger than the diffraction efficiency of the 0th order diffracted light in the second diffraction region.
前記第 1の回折領域および前記第 2の回折領域は帯状に形成され、  The first diffraction region and the second diffraction region are formed in a band shape,
前記第 1の回折領域における格子及び Z又は前記第 2の回折領域における格子 力 前記第 1の回折領域に対して傾斜している、請求の範囲第 1項記載の光ピックァ ップ装置。 The optical picker according to claim 1, wherein the grating in the first diffraction region and Z or the grating force in the second diffraction region are inclined with respect to the first diffraction region. Equipment.
前記第 1の回折領域において生成される 0次回折光が、前記光情報記録媒体に対 して情報信号を記録又は再生するためのメインビームとして用いられ、  0th-order diffracted light generated in the first diffraction region is used as a main beam for recording or reproducing an information signal with respect to the optical information recording medium,
前記第 2の回折領域において生成される ± 1次回折光が、サブビームとして用いら れる、請求の範囲第 19項記載の光ピックアップ装置。  20. The optical pickup device according to claim 19, wherein the ± first-order diffracted light generated in the second diffraction region is used as a sub beam.
PCT/JP2007/054987 2006-03-31 2007-03-13 Optical pickup device WO2007114006A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10124906A (en) * 1996-10-16 1998-05-15 Sankyo Seiki Mfg Co Ltd Wavelength plate and optical pickup device using the same
JP2001014717A (en) * 1999-04-28 2001-01-19 Matsushita Electronics Industry Corp Optical device
JP2005339766A (en) * 2004-04-23 2005-12-08 Matsushita Electric Ind Co Ltd Optical disk apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10124906A (en) * 1996-10-16 1998-05-15 Sankyo Seiki Mfg Co Ltd Wavelength plate and optical pickup device using the same
JP2001014717A (en) * 1999-04-28 2001-01-19 Matsushita Electronics Industry Corp Optical device
JP2005339766A (en) * 2004-04-23 2005-12-08 Matsushita Electric Ind Co Ltd Optical disk apparatus

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