JP2012048786A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup device which can read a signal recorded on optical discs having different standards using three laser beams each having a different wavelength.SOLUTION: An optical magnification of a forward path that leads first laser beams to a first optical disc and an optical magnification of a return path that leads return beams reflected from the first optical disc to an optical photodetector 16 are set by a first power lens 17 and a second power lens 18. An optical magnification of a forward path that leads second laser beams or third laser beams to a second optical disc or a third optical disc is set by the first power lens 17, and an optical magnification of a return path that leads return beams reflected from the second optical disc or the third optical disc to the optical photodetector 16 is set by the first power lens 17 and the second power lens 18.

Description

  The present invention relates to an optical pickup device that performs reading operation of a signal recorded on an optical disc and recording operation of a signal on an optical disc by laser light.

  2. Description of the Related Art Optical disk apparatuses that can perform signal reading operation and signal recording operation by irradiating a signal recording layer of an optical disk with laser light emitted from an optical pickup device have been widely used.

  As an optical disk apparatus, an apparatus using an optical disk called a CD or a DVD is generally widespread. Recently, an optical disk with improved recording density, that is, an apparatus using a Blu-ray standard optical disk has been developed.

  As a laser beam for performing a read operation of a signal recorded on a CD standard optical disc, an infrared light having a wavelength of 785 nm is used. As a laser beam for performing a read operation of a signal recorded on a DVD standard optical disc, , Red light having a wavelength of 655 nm is used.

  Further, the thickness of the transparent protective layer provided between the signal recording layer and the surface of the optical disc in the CD standard optical disc is 1.2 mm, and is used to read out signals from the signal recording layer. The numerical aperture of the objective lens to be set is set to 0.47. The thickness of the transparent protective layer provided between the signal recording layer in the DVD standard optical disc and the surface of the optical disc is 0.6 mm, and is used to read out signals from the signal recording layer. The numerical aperture of the objective lens to be set is set to 0.6.

  For such CD standard and DVD standard optical disks, the laser light for performing the read operation of the signals recorded on the Blu-ray standard optical disk is a laser light having a short wavelength, for example, a blue-violet light having a wavelength of 405 nm. in use.

  The thickness of the protective layer provided on the upper surface of the signal recording layer in the Blu-ray standard optical disc is 0.1 mm, and the aperture of the objective lens used to read out signals from the signal recording layer The number is set to 0.85.

  The diameter of a laser spot generated by reading a signal recorded on a signal recording layer provided on a Blu-ray standard optical disc or by condensing a laser beam to record a signal on the signal recording layer Need to be small. The objective lens used to obtain a desired laser spot shape has a feature that not only the numerical aperture is increased but also the focal length is shortened, so that the radius of curvature of the objective lens is reduced.

An optical disc apparatus capable of reading and recording signals recorded on all the optical discs of the CD standard, the DVD standard, and the Blu-ray standard described above has been commercialized, and is incorporated into such an optical disc apparatus. As an optical pickup device, a laser diode that emits a first laser beam that performs an operation of reading a signal recorded on a Blu-ray standard optical disc, and the first laser beam emitted from the laser diode is condensed on a signal recording layer. Two wavelengths for emitting a first objective lens, a second laser beam for performing a read operation of a signal recorded on a DVD standard optical disc, and a third laser beam for performing a read operation of a signal recorded on a CD standard optical disc Laser diode, and second and third laser beams Optical pickup device in which the second objective lens is incorporated for converging the signal recording layer of the click is generally employed (see Patent Document 1.).

JP 2010-61781 A

  A laser diode that emits a laser beam of one wavelength, a two-wavelength laser diode that emits a laser beam of two wavelengths, and a reading operation of signals recorded on three optical discs of different standards by two objective lenses In the optical pickup apparatus configured as described above, when an optical path is provided for each laser beam, many optical parts are required, which is not only expensive, but also cannot be reduced in size.

  As a method for solving such a problem, the optical paths of the first laser light, the second laser light, and the third laser light are made common. A conventional optical pickup device having such a configuration will be described with reference to FIGS.

  In FIG. 3, reference numeral 1 denotes a laser diode that generates and emits first laser light having a wavelength of 405 nm, for example, blue-violet light, and 2 denotes a first diffraction grating on which the first laser light emitted from the laser diode 1 is incident. There is a diffraction grating section 2a that separates laser light into zero-order main beam, + 1st-order light, and two sub-beams that are −1st-order light, and 1 that converts incident laser light into linearly polarized light in the S direction. / 2 wavelength plate 2b.

  3, for example, a first laser element that generates and emits second laser light that is red light having a wavelength of 655 nm and a second laser element that generates and emits third laser light that is infrared light of 785 nm are housed in the same case. This is a two-wavelength laser diode.

  Reference numeral 4 denotes a second diffraction grating on which the second laser light emitted from the first laser element incorporated in the two-wavelength laser diode 3 and the third laser light emitted from the second laser element are incident. A diffraction grating portion 4a that separates light into a main beam that is zero-order light, two sub-beams that are + 1st-order light, and two sub-beams that are −1st-order light, and a ½ wavelength that converts incident laser light into linearly polarized light in the S direction It consists of a plate 4b.

  Reference numeral 5 denotes a divergence lens provided at a position where the second laser light and the third laser light emitted from the two-wavelength laser diode 3 are incident through the second diffraction grating 4, and is incident divergent light. It functions to adjust the divergence angle of the laser beam.

  Reference numeral 6 denotes a first laser beam, a second laser beam, and a third laser beam that reflect the S-polarized light of the first laser beam incident through the first diffraction grating 2 and reflected from the optical disk through an optical path to be described later. This is a half mirror that transmits the P-polarized light that is the return light. 7 reflects the S-polarized light of the second laser beam and the third laser beam incident through the second diffraction grating 4 and the divergence lens 5 and the first laser beam incident after being reflected by the half mirror 6. It is a polarization beam splitter that transmits P-polarized light that is transmitted through and reflected from the optical disk and that is return light of the first laser light, the second laser light, and the third laser light.

In the polarizing beam splitter 7 having such a configuration, a part of the S-polarized light of the second laser light and the third laser light incident through the second diffraction grating 4 and the divergence lens 5 is transmitted and reflected from the half mirror 6. Is configured to reflect a portion of the S-polarized light of the first laser light incident thereon. 8 is a front monitor diode provided at a position where the first laser light reflected by the polarizing beam splitter 7, the second laser light transmitted through the polarizing beam splitter 7, and the third laser light are irradiated; A detection signal corresponding to the output of each laser beam is output. That is, the laser output can be controlled to a desired laser output by using the detection signal obtained from the front monitor diode 8.

  9 is provided at a position where the first laser light transmitted through the polarizing beam splitter 7, the second laser light reflected by the polarizing beam splitter 7 and the third laser light are incident, and having three different wavelengths. This is a three-wavelength type quarter-wave plate that functions to convert incident laser light corresponding to laser light from linearly polarized light to circularly polarized light, and conversely from circularly polarized light to linearly polarized light.

  Reference numeral 10 denotes a collimator lens for converting the incident laser light into parallel light as the laser light transmitted through the quarter-wave plate 9 is incident thereon. The collimating lens 10 is displaced in the optical axis direction by the displacement operation of the optical disk. The spherical aberration generated based on the thickness of the protective layer is corrected.

  Reference numeral 11 denotes a first objective lens that condenses the first laser beam on the signal recording layer L1 provided on the first optical disc D1 (see FIG. 2), and reference numeral 12 denotes a second laser beam provided on the second optical disc D2. The second objective lens focuses light on the signal recording layer L2 and focuses the third laser light on the signal recording layer L3 provided on the third optical disc D3. In such a configuration, the first objective lens 11 and the second objective lens 12 are, for example, displaced by a four support wires in a focusing direction perpendicular to the surface of the optical disc and in a radial direction of the optical disc. It is mounted on a member called a lens holder that is supported so that it can be displaced in the direction.

  The first laser light, the second laser light, and the third laser light transmitted through the collimating lens 10 are configured to be guided to the first objective lens 11 and the second objective lens 12 by the optical system shown in FIG. . In FIG. 2, reference numeral 13 denotes a wavelength selective element, which is configured to transmit the first laser light and reflect the second laser light and the third laser light toward the second objective lens 12. Reference numeral 14 denotes a rising mirror that reflects the first laser light transmitted through the wavelength selective element 13 toward the first objective lens 11. Such a configuration is the same as the technique described in Patent Document 1.

  In such a configuration, the first laser light transmitted through the collimator lens 10 is transmitted through the wavelength selective element 13, reflected by the rising mirror 14, and incident on the first objective lens 11. Thus, the first laser light incident on the first objective lens 11 is condensed on the signal recording layer L1 provided on the first optical disc D1 by the condensing operation of the first objective lens 11. Become.

The second laser light transmitted through the collimator lens 10 is reflected by the wavelength selective element 13 and is incident on the second objective lens 12. Thus, the second laser light incident on the second objective lens 12 is condensed on the signal recording layer L2 provided on the second optical disc D2 by the condensing operation of the second objective lens 12. Become. Then, the third laser light transmitted through the collimating lens 10 is reflected by the wavelength selective element 13 and is incident on the second objective lens 12. Thus, the third laser light incident on the second objective lens 12 is condensed on the signal recording layer L3 provided on the third optical disc D3 by the condensing operation of the second objective lens 12. Become.

  In such a configuration, the first laser light emitted from the laser diode 1 is transmitted through the first diffraction grating 2, the half mirror 6, the polarization beam splitter 7, the quarter wavelength plate 9, the collimating lens 10, the wavelength selective element 13, and the like. After being incident on the first objective lens 11 via the rising mirror 14, the signal recording layer L1 provided on the first optical disc D1 is irradiated as a focused spot by the focusing operation of the first objective lens 11. However, the first laser light applied to the signal recording layer L1 is reflected as return light by the signal recording layer L1.

  The second laser light emitted from the first laser element of the two-wavelength laser diode 3 is a second diffraction grating 4, a divergence lens 5, a polarization beam splitter 7, a quarter-wave plate 9, a collimating lens 10, and a wavelength selection. After being incident on the second objective lens 12 via the directional element 13, the signal recording layer L2 provided on the second optical disc D2 is irradiated as a focused spot by the focusing operation of the second objective lens 12. The second laser light applied to the signal recording layer L2 is reflected as return light by the signal recording layer L2.

  The third laser light emitted from the second laser element of the two-wavelength laser diode 3 is a second diffraction grating 4, a divergence lens 5, a polarization beam splitter 7, a quarter-wave plate 9, a collimating lens 10, and a wavelength selection. After being incident on the second objective lens 12 via the directional element 13, the signal recording layer L3 provided on the third optical disc D3 is irradiated as a focused spot by the focusing operation of the second objective lens 12. The third laser light applied to the signal recording layer L3 is reflected as return light by the signal recording layer L3.

  The return light of the first laser beam reflected from the signal recording layer L1 of the first optical disc D1 is a first objective lens 11, a rising mirror 14, a wavelength selective element 13, a collimating lens 10, a quarter wavelength plate 9, and The light enters the half mirror 6 through the polarization beam splitter 7. The return light incident on the half mirror 6 in this way is changed to linearly polarized light in the P direction by the phase changing operation by the quarter wavelength plate 9. Therefore, the return light of the first laser light is not reflected by the half mirror 6, but passes through the half mirror 6 as control laser light.

  The return light of the second laser light reflected from the signal recording layer L2 of the second optical disk D2 is the second objective lens 12, the wavelength selective element 13, the collimating lens 10, the quarter wavelength plate 9, and the polarization beam splitter. 7 enters the half mirror 6. The return light incident on the half mirror 6 in this way is changed to linearly polarized light in the P direction by the phase changing operation by the quarter wavelength plate 9. Therefore, the return light of the second laser light is not reflected by the half mirror 6, but passes through the half mirror 6 as control laser light.

  The return light of the third laser light reflected from the signal recording layer L3 of the third optical disc D3 is the second objective lens 12, the wavelength selective element 13, the collimating lens 10, the quarter wavelength plate 9, and the polarization beam splitter. 7 enters the half mirror 6. The return light incident on the half mirror 6 in this way is changed to linearly polarized light in the P direction by the phase changing operation by the quarter wavelength plate 9. Therefore, the return light of the third laser light is not reflected by the half mirror 6, but passes through the half mirror 6 as control laser light.

Reference numeral 15 denotes an AS plate on which the control laser beam transmitted through the half mirror 6 is incident. The size of the astigmatism generated by the half mirror 6 is a size suitable for generating a focus error signal. In addition to the function of enlarging, the coma aberration generated in the half mirror 6 is corrected. Reference numeral 16 denotes a photodetector 14 that is irradiated with control laser light through the AS plate 15 and is provided with a known quadrant sensor or the like, which is recorded on the signal recording layer of the optical disc by the main beam irradiation operation. A focus error signal generating operation for performing a signal generating operation accompanying a signal reading operation and a focusing control operation by an astigmatism method, and a tracking error signal generating operation for performing a tracking control operation by irradiation of two sub beams are performed. It is configured as follows. Since such control operations for generating various signals are well known, the description thereof is omitted.

  As described above, the first laser light emitted from the laser diode 1 goes to the signal recording layer L1 of the first optical disc D1, and the second laser light emitted from the second wavelength laser diode 3 records the signal on the second optical disc D2. Comparing the forward path to the layer L2 and the forward path of the third laser light emitted from the two-wavelength laser diode 3 to the signal recording layer L3 of the third optical disc D3, the optical path from the polarization beam splitter 7 to the wavelength selective element 13 is You can see that they are also used.

  Then, the return path of the return light of the first laser light reflected from the signal recording layer L1 of the first optical disk D1 to the photodetector 16, the return of the second laser light reflected from the signal recording layer L2 of the second optical disk D2 Comparing the return path of the light to the photodetector 16 and the return path of the return light of the third laser light reflected from the signal recording layer L3 of the third optical disc D3, the light from the wavelength selective element 13 is compared. It can be seen that the optical path to the detector 16 is also used.

  The conventional optical pickup device shown in FIG. 3 combines the forward path for guiding the laser light to the signal recording layer of the optical disk and the return path for guiding the return light reflected from the signal recording layer of the optical disk to the photodetector 16. The number of optical components can be reduced. As a result, the manufacturing cost can be reduced and the optical pickup device can be downsized.

  In the optical pickup device having such a configuration, if the optical magnification in the forward path and the optical magnification in the backward path are greatly different, a positional deviation between the light receiving unit such as a four-divided sensor incorporated in the photodetector 16 and the spot of the return light occurs. There is a problem that it is easy. In the conventional example described above as a method for solving such a problem, the divergence lens 5 is provided in the forward path of the second laser light and the third laser light emitted from the two-wavelength laser diode 3. That is, by adjusting the optical magnification with such a divergence lens 5, it is possible to suppress the occurrence of spot displacement, but there is a problem that workability is poor because the divergence lens 5 needs to be fixed and adjusted accurately. .

  The present invention is intended to provide an optical pickup device that can solve such a problem.

The present invention relates to a laser diode that emits a laser beam having a first wavelength for performing a read operation of a signal recorded on a first optical disc having a short distance from the surface of the optical disc to the signal recording layer, from the surface of the optical disc to the signal recording layer. A second wavelength laser beam for performing a read operation of a signal recorded on a second optical disc having a longer distance than the first optical disc, and a third optical disc having a longer distance from the surface of the optical disc to the signal recording layer than the second optical disc In an optical pickup device incorporating a two-wavelength laser diode that emits two laser beams of a third wavelength that performs a read operation of a signal recorded on the first laser beam, the first laser beam emitted from the laser diode is In addition to guiding toward the objective lens, the signal recording layer of the first optical disc and the second optical disc A first polarizing member that guides the first laser beam, the second laser beam, and the third laser beam reflected from the signal recording layer of the first optical disc and the signal recording layer of the third optical disc toward the photodetector, the first polarizing member, and the objective A second laser beam and a third laser beam emitted from the two-wavelength laser diode and guided toward the objective lens, and a signal recording layer of the first optical disc and a signal of the second optical disc A second polarizing member that guides the first laser light, the second laser light, and the third laser light reflected from the recording layer and the signal recording layer of the third optical disc in the direction of the first polarizing member; the second polarizing member; The polarization direction of the first laser beam, the second laser beam, and the third laser beam is changed from linearly polarized light to circularly polarized light, and from circularly polarized light to linearly polarized light. A three-wavelength-compatible quarter-wave plate, a first power lens that is provided between the second polarizing member and the objective lens, and that adjusts and changes the transmission angle of laser light, and the first polarizing member And a second power lens that adjusts and changes the transmission angle of the laser light and is provided between the first polarizing member and the second polarizing member. The optical magnification of the forward path for guiding the first laser light to the first optical disk and the first optical disk The optical power of the return path for guiding the return light reflected from the light to the photodetector is set by the first power lens and the second power lens, and the second laser light and the third laser light are applied to the second optical disk and the third optical disk. The optical magnification of the forward path to be guided is set by the first power lens, and the optical magnification of the return path to guide the return light reflected from the second optical disc and the third optical disc to the photodetector is set to the first power level. And a second power lens.

  In the present invention, recording is performed on each signal recording layer by focusing the first, second, and third laser beams having different wavelengths on the signal recording layers provided on the first, second, and third optical discs having different standards. In the optical pickup device configured to perform the read operation of the signal that has been read, the optical magnification of the forward path for guiding the first laser light to the first optical disc and the return light reflected from the first optical disc are guided to the photodetector. The optical magnification of the return path is set by the first power lens and the second power lens, and the optical magnification of the forward path for guiding the second laser light and the third laser light to the second optical disk and the third optical disk is set by the first power lens. In addition, the first power lens and the second power lens set the optical magnification of the return path that guides the return light reflected from the second optical disk and the third optical disk to the photodetector. Since the so that, that is, since it possible to set the optical magnification of the forward path and backward path suitable for each laser beam has the advantage that it is possible to suppress the position deviation of the optical detector.

It is the schematic which shows one Example of the optical pick-up apparatus which concerns on this invention. It is a figure which shows a part of Example of the optical pick-up apparatus based on this invention. It is the schematic which shows one Example of the conventional optical pick-up apparatus.

  Using a laser diode that generates a single laser beam and a two-wavelength laser diode that generates two laser beams of different wavelengths, it is recorded on a signal recording layer provided on an optical disc of a different standard. It is related with the optical pick-up apparatus comprised so that the read-out operation | movement of the signal may be performed.

  FIG. 1 shows an embodiment of an optical pickup device according to the present invention. Components having the same functions as those of the optical pickup device shown in FIG.

  In the optical pickup device of the present invention, a first power lens 17 for adjusting and changing the transmission angle of laser light is disposed between the quarter-wave plate 9 and the objective lenses 11 and 12 as shown in the drawing, and the half mirror 6 A second power lens 18 for adjusting and changing the transmission angle of the laser light is disposed between the polarizing beam splitter 7 and the polarizing beam splitter 7.

  In such a configuration, the first power lens 17 is set to have a positive power characteristic, and the second power lens 18 is set to have a negative power characteristic. According to such a configuration, the first laser light generated and emitted from the laser diode 1 is the first diffraction grating 2, the half mirror 6, the second power lens 18, the polarization beam splitter 7, the quarter wavelength plate 9, The light is guided to the first objective lens 11 through the 1 power lens 17, the wavelength selective element 13, and the rising mirror 14, and is condensed on the signal recording layer L 1 of the first optical disc D 1 by the condensing operation of the first objective lens 11. Is done.

  The return light of the first laser beam reflected from the signal recording layer L1 of the first optical disc D1 is the first objective lens 11, the rising mirror 14, the wavelength selective element 13, the first power lens 17, 1 / The light is irradiated onto the photodetector 16 through the four-wavelength plate 9, the polarizing beam splitter 7, the second power lens 18, the half mirror 6 and the AS plate 15.

  As described above, the second power lens 18 and the first power lens 17 are inserted in the forward path of the first laser light emitted from the laser diode 1, and the first power lens 17 is inserted in the return path as the return light of the first laser light. The power lens 17 and the second power lens 18 are inserted. That is, since the optical system of the first laser beam that performs the reading operation of the signal recorded on the signal recording layer L1 of the first optical disc D1 has the same lens configuration for the forward path and the backward path, the optical magnification of the forward path and the return path The optical magnification is made equal, and the position shift of the photodetector can be prevented.

  Next, the second laser light generated and emitted from the two-wavelength laser diode 3 passes through the second diffraction grating 4, the polarization beam splitter 7, the quarter-wave plate 9, the first power lens 17, and the wavelength selective element 13. Then, the light is guided to the second objective lens 12 and is focused on the signal recording layer L2 of the second optical disc D2 by the focusing operation of the second objective lens 12.

  The return light of the second laser light reflected from the signal recording layer L2 of the second optical disc D2 includes the second objective lens 12, the wavelength selective element 13, the first power lens 17, the quarter wavelength plate 9, The light is irradiated onto the photodetector 16 through the polarization beam splitter 7, the second power lens 18, the half mirror 6 and the AS plate 15.

  The third laser light generated and emitted from the two-wavelength laser diode 3 passes through the second diffraction grating 4, the polarization beam splitter 7, the quarter-wave plate 9, the first power lens 17, and the wavelength selective element 13. The light is guided to the second objective lens 12 and focused on the signal recording layer L3 of the third optical disc D3 by the focusing operation of the second objective lens 12.

  The return light of the third laser beam reflected from the signal recording layer L3 of the third optical disc D3 includes the second objective lens 12, the wavelength selective element 13, the first power lens 17, the quarter wavelength plate 9, The light is irradiated onto the photodetector 16 through the polarization beam splitter 7, the second power lens 18, the half mirror 6 and the AS plate 15.

  As described above, the first power lens 17 is inserted in the forward path of the second laser light and the third laser light emitted from the two-wavelength laser diode 3, and is the return light of the second laser light and the third laser light. The first power lens 17 and the second power lens 18 are inserted in the return path. That is, the optical system of the second laser beam and the third laser beam that performs the read operation of the signals recorded on the signal recording layer L2 of the second optical disc D2 and the signal recording layer L3 of the third optical disc D3 is the forward path and the backward path. Since the lens configuration is different, the optical power ratio of the conventional forward path and the backward path can be reduced by using a lens having a negative power characteristic as the second power lens 18 in particular. It can be set to a value that suppresses the positional deviation.

In addition, according to such a configuration, the optical system that performs the read operation of the signal recorded on the signal recording layer L2 of the second optical disc D2 and the read operation of the signal recorded on the signal recording layer L2 of the third optical disc D3. Since one power lens is inserted in the forward path, that is, an optical system similar to the conventional optical system is used, laser output is performed as in the case of recording signals on the second optical disk D2 and the third optical disk D3. When it is necessary to increase the laser power, it is possible to prevent the laser output from being insufficient.

  In this embodiment, the half mirror 6 is used as the first polarizing member and the polarizing beam splitter 7 is used as the second polarizing member. However, a polarizing beam splitter can also be used as the first polarizing member. .

  Although the description has been given of the case where the optical pickup apparatus that performs the reading operation of the signal recorded on the optical disc of the CD standard, the DVD standard, and the Blu-ray standard has been described, the reading operation of the signal recorded on the optical disc of another different standard has been described. It can also be implemented in an optical pickup device that can be used.

DESCRIPTION OF SYMBOLS 1 Laser diode 3 2 wavelength laser diode 6 Half mirror 7 Polarizing beam splitter 9 1/4 wavelength plate 11 1st objective lens 12 2nd objective lens 16 Photo detector 17 1st power lens 18 2nd power lens

Claims (3)

A laser diode that emits a laser beam of a first wavelength that performs a read operation of a signal recorded on a first optical disc with a short distance from the surface of the optical disc to the signal recording layer, and a distance from the surface of the optical disc to the signal recording layer The laser beam having the second wavelength for performing the reading operation of the signal recorded on the second optical disc longer than the first optical disc and the third optical disc in which the distance from the surface of the optical disc to the signal recording layer is longer than the second optical disc. In an optical pickup device incorporating a two-wavelength laser diode that emits two laser beams of a third wavelength that performs a readout operation of a signal being transmitted, the first laser beam emitted from the laser diode is directed toward the objective lens And the signal recording layer of the first optical disc and the signal recording of the second optical disc. A first polarizing member that guides the first laser light, the second laser light, and the third laser light reflected from the signal recording layer of the layer and the third optical disc toward the photodetector, and the first polarizing member and the objective lens A second laser beam and a third laser beam provided between the two-wavelength laser diodes and guided toward the objective lens, and a signal recording layer of the first optical disc, a signal recording layer of the second optical disc, A second polarizing member that guides the first laser light, the second laser light, and the third laser light reflected from the signal recording layer of the third optical disc in the direction of the first polarizing member; and the second polarizing member and the objective lens. Three waves that are provided in between and convert the polarization directions of the first laser beam, the second laser beam, and the third laser beam from linearly polarized light to circularly polarized light, and from circularly polarized light to linearly polarized light. Corresponding ¼ wavelength plate, a first power lens that is provided between the second polarizing member and the objective lens and adjusts and changes the transmission angle of the laser beam, the first polarizing member, and the second The second power lens is provided between the polarizing member and adjusts and changes the transmission angle of the laser beam, and is reflected from the optical magnification of the forward path for guiding the first laser beam to the first optical disc and from the first optical disc. The optical power of the return path for guiding the return light to the photodetector is set by the first power lens and the second power lens, and the forward path for guiding the second laser light and the third laser light to the second optical disk and the third optical disk. The optical power is set by the first power lens and the optical power of the return path for guiding the return light reflected from the second optical disk and the third optical disk to the photodetector is set by the first power lens and the first power lens. An optical pickup device characterized in that it is set by a two-power lens. 2. The optical pickup device according to claim 1, wherein a half mirror is used as the first polarizing member and a polarizing beam splitter is used as the second polarizing member. 3. The optical pickup device according to claim 2, wherein a polarizing beam splitter is used as the first polarizing member.

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