JP2008077821A - Optical pickup apparatus and optical disk apparatus equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adapt an optical pickup apparatus to various media such as a conventional optical disk and a high density recording optical disk, and to obtain a small and thin optical pickup apparatus. <P>SOLUTION: The optical pickup apparatus includes at least: a first light emitting element 10 that can emit a first wavelength light; a second light emitting element 20 that can emit a second wavelength light which is different from the first wavelength light; a first objective lens 60 that condenses the first wavelength light on a first medium; and a second objective lens 70 that condenses the second wavelength light on a second medium which is based on a different standard from the first medium. When optical paths L1i and L1ii on which the first wavelength light reaches the first medium from the first light emitting element 10 via the first objective lens 60, are determined to be a first optical path L1 and optical paths L2i and L2ii on which the second wavelength light reaches the second medium from the second light emitting element 20 via the second objective lens 70, are determined to be a second optical path L2, the first optical path L1 and the second optical path L2 intersect. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is, for example, “CD” (Compact Disc) (trademark), “DVD” (registered trademark) (Digital Versatile Disc), “HD DVD” (registered trademark) (High Definition DVD), or “Blu-ray Disc”. To an optical pickup device capable of reproducing data recorded on any one of a plurality of media such as “registered trademark” and recording data on any of the plurality of media, and an optical disk device including the same It is.

  FIG. 9 is a schematic view showing an embodiment of a conventional optical pickup device.

  An optical disk device is used to reproduce or record data such as information on a medium. Media means media that records and mediates information and media that records and transmits information. Examples of the medium include an optical disc 700 such as a CD (Compact Disc).

  A current is passed from the laser driver 510 to the laser diode 520, and laser light / laser (LASER: light amplification by stimulated emission of radiation) is output from the laser diode 520. The laser driver 510 constitutes a laser driving circuit 510 that drives the laser diode 520 to emit laser light from the laser diode 520. A current is supplied from the laser driver 510 to the laser diode 520, and information is recorded on the disk 700, for example, or information recorded on the disk 700 is reproduced by the laser light emitted from the laser diode 520. .

  The laser light output from the laser diode 520 is irradiated onto the disk 700 via the diffraction grating 530, the intermediate lens 540, the half mirror 550, and the objective lens 560. The diffraction grating 530 is configured to divide the laser light emitted from the laser diode 520 into several beams (not shown) by utilizing light diffraction. The objective lens 560 plays a role of condensing the laser beam on the signal portion 701 of the disc 700. Part of the laser light reflected from the disk 700 is returned to the photodetector 570 or the like. The photodetector 570 receives light, converts the signal into an electrical signal, and outputs a signal for operating a servo mechanism (not shown) of a lens holder (not shown) of the optical pickup device 501. The servo or servo mechanism means a mechanism that measures the state of the object to be controlled, compares the measured value with a reference value, and automatically performs correction control.

  Further, a part of the laser light output from the laser diode 520 enters the front monitor diode 580. The front monitor diode 580 monitors the laser light output from the laser diode 520 and applies feedback to control the laser diode 520.

  The laser driver 510, the laser diode 520, the diffraction grating 530, the intermediate lens 540, the half mirror 550, the objective lens 560, the photodetector 570, and the front monitor diode 580 are attached to a housing (not shown). The housing means, for example, a box-shaped object in which an object such as a device or a part is accommodated, or something similar to a box.

The laser driver 510, the laser diode 520, the photo detector 570, and the front monitor diode 580 are connected to the flexible printed circuit 505 so as to be energized. A process for manufacturing the flexible printed circuit will be described. For example, a plurality of circuit conductors to be a metal foil such as a copper foil are printed in parallel on the insulating sheet. A protective layer is provided thereon to form a flexible printed circuit.

  The optical pickup device 501 is configured to include the various types described above. The optical pickup device 501 includes other components (not shown) in addition to those shown in the drawing, but these components are omitted in FIG. 9 for convenience.

  The laser light emitted from the laser diode 520 of the optical pickup device 501 passes through the objective lens 560 and is applied to an optical disc 700 such as a CD installed in the player body. For example, information is recorded on the optical disc 700 or information recorded on the optical disc 700 is reproduced by the laser light emitted from the laser diode 520. In this manner, information is recorded or reproduced in the optical disc apparatus.

  As a conventional optical pickup device, for example, there is an optical pickup that is compatible with a CD (Compact Disc) shape and a DVD (Digital Versatile Disc) that do not require a separate variable aperture (see, for example, Patent Document 1). ).

Further, as related to the conventional optical pickup device, for example, there are an optical pickup device and an optical disc device that can realize at least one of thinning and miniaturization even in response to lasers of various wavelengths including a blue laser (for example, (See Patent Document 2).
Japanese Patent Laid-Open No. 11-224436 (pages 1, 3 and 3) Japanese Patent Laying-Open No. 2005-32286 (pages 1, 3 and 1)

  In recent years, media of various standards such as the “Blu-ray Disc” standard and the “HD DVD” standard that enable higher density recording than the conventional CD standard and DVD standard have been announced. However, the conventional optical pickup device 501 shown in FIG. 9 is compatible only with the conventional optical disc 700 such as a CD, and is not compatible with a high-density recording optical disc such as a Blu-ray Disc.

  The new Blu-ray Disc standard media, which is not compatible with the conventional standard, and capable of high-density recording, is different from the DVD standard media such as “HD DVD” and the CD standard media. It is a standard. Until now, it has been difficult to develop a single optical pickup device that can handle the media of completely different standards.

  In order to cope with this, an optical disk device (not shown) including a plurality of optical pickup devices capable of handling each medium has been considered. For example, a first optical pickup device (not shown) corresponding to a Blu-ray Disc standard medium and a second optical pickup device (not shown) corresponding to a DVD standard medium and a CD standard medium An optical disk device provided with two optical pickup devices has also been considered.

  However, a plurality of optical pickup devices including a first optical pickup device (not shown) corresponding to the Blu-ray Disc standard media and a second optical pickup device (not shown) corresponding to the DVD standard media and the CD standard media are provided. Since the optical disk device provided is increased in the number of parts, there is a concern that the optical disk device is increased in size and weight, and the price is increased.

In recent years, there has been a demand for further downsizing / thinning of notebook or laptop personal computers and desktop personal computers. A personal computer (PC) will be described. Since a notebook PC or laptop PC is required to be light and thin, it has a structure including an optical disk device equipped with a slim type drive. . A notebook PC or a laptop PC has a display and a PC main body that have a single structure, and the display is folded with respect to the PC main body, so that the PC or the laptop PC has a small size. The notebook PC is, for example, a general-purpose PC having a size of about A4 or smaller when viewed in plan, and is also called a book PC, for example. Notebook PCs or laptop PCs are compact and can be easily carried. In contrast to notebook PCs or laptop PCs, desktop computers are desktop computers and are computers that can be used on a desk, but are not easily portable. .

  PC assembly / manufacturers such as notebook PCs, laptop PCs, desktop PCs, etc. are able to support the new Blu-ray Disc standard media group and media such as "HD DVD". In addition, there is a demand for an optical pickup device that can handle a DVD standard media group that can handle conventional DVDs and a CD standard media group that is a conventional standard, and an optical disk device that includes such an optical pickup device. ing.

  The present invention is to solve the above problems. SUMMARY OF THE INVENTION In view of the above, the present invention provides an optical pickup device capable of supporting various media such as a conventional optical disc to a high-density recording optical disc, and capable of being reduced in size and thickness, and an optical disc apparatus including the same. The purpose is to do.

  In order to achieve the above object, an optical pickup device according to a first aspect of the present invention includes a first light emitting element capable of emitting first wavelength light, and second wavelength light having a wavelength different from the first wavelength light. A second light emitting element capable of emitting light, a first objective lens for condensing the first wavelength light on the first medium, and the second wavelength light on a second medium of a standard medium different from the first medium A second objective lens for condensing, and determining an optical path of the first wavelength light from the first light emitting element to the first medium via the first objective lens as a first optical path, When the optical path of the second wavelength light from the second light emitting element to the second medium via the second objective lens is determined as a second optical path, the first optical path and the second optical path Crossing each other.

  Even if the standard of the first media and the standard of the second media are different from each other, the optical pickup device corresponding to at least the first media and the second media of the standard media different from the first media is provided. Is possible. A first light emitting element capable of emitting first wavelength light, a second light emitting element capable of emitting second wavelength light having a wavelength different from the first wavelength light, and condensing the first wavelength light on the first medium. If an optical pickup device comprising a first objective lens for focusing and a second objective lens for condensing the second wavelength light on a second medium of a standard medium different from the first medium is configured, one optical pickup device Thus, for example, at least a high-density recording standard first medium and a second standard medium different from the first medium can be supported. Accordingly, it is possible to provide an optical pickup device that supports various media of different standards. In addition, a first optical path that is an optical path of the first wavelength light from the first light emitting element through the first objective lens to the first medium, and a second optical element from the second light emitting element through the second objective lens. By crossing the second optical path which is the optical path of the second wavelength light until reaching the two media, the optical pickup device can be reduced in size and thickness.

  The optical pickup device according to claim 2 is the optical pickup device according to claim 1, wherein the first wavelength light is guided to an optical path passing through the first objective lens or an optical path passing through the second objective lens. A member is provided.

  With the above configuration, an optical pickup device compatible with various media of different standards can be configured. When the polarizing member is installed in the optical pickup device, the first wavelength light emitted from the first light emitting element is guided to the optical path via the first objective lens. Or the 1st wavelength light radiate | emitted from the 1st light emitting element is guide | induced to the optical path which passes along a 2nd objective lens. By installing the polarizing member in the optical pickup device, the optical pickup device can support various media.

  The optical pickup device according to claim 3 is the optical pickup device according to claim 2, wherein when the first wavelength light is transmitted through the polarizing member, the first wavelength light passes through the first objective lens. When the first wavelength light is reflected by the polarizing member, the first wavelength light passes through the second objective lens.

  With the above configuration, the first wavelength light emitted from the first light emitting element is condensed on the first medium by the first objective lens. Or the 1st wavelength light radiate | emitted from the 1st light emitting element is condensed by the 2nd objective lens on the other medium made into a medium different from a 1st medium, and a medium different from a 2nd medium. . The first wavelength light is condensed on the first medium or another medium different from the first medium and the second medium by utilizing the transmission characteristic or reflection characteristic for the first wavelength light included in the polarizing member. It becomes possible to make it.

  The optical pickup device according to claim 4 is the optical pickup device according to claim 2 or 3, wherein the second wavelength light is guided to an optical path passing through the second objective lens by the polarizing member. And

  With the above configuration, an optical pickup device corresponding to various media of different standards is configured. When the optical pickup device is equipped with the polarizing member that guides the second wavelength light to the optical path reaching the second medium via the second objective lens, the optical pickup device can cope with various media.

  The optical pickup device according to claim 5 is the optical pickup device according to any one of claims 2 to 4, wherein the second wavelength light passes through the polarizing member and passes through the second objective lens. It is characterized by that.

  With the above configuration, the second wavelength light emitted from the second light emitting element is condensed on the second medium by the second objective lens. The second wavelength light can be condensed on the second medium by using the transmission characteristic of the second wavelength light included in the polarizing member.

  The optical pickup device according to a sixth aspect is the optical pickup device according to any one of the second to fifth aspects, wherein the polarizing member is disposed at an optical path intersection where the first optical path and the second optical path intersect. It is characterized by being located.

  With the above configuration, it is possible to reduce the size and thickness of an optical pickup device that can handle various media. By positioning the polarizing member at the optical path intersection where the first optical path and the second optical path intersect, the optical layout in the optical pickup device can be made compact. Therefore, it is possible to provide a small / thin optical pickup device that can handle various media.

  An optical pickup device according to a seventh aspect is the optical pickup device according to any one of the second to sixth aspects, wherein the first wavelength light passing through the polarizing member is a P wave. One wavelength light is transmitted through the polarizing member and passes through the first objective lens.

  With the above configuration, the P-wavelength first wavelength light is reliably condensed on the first medium through the polarizing member, via the first objective lens. “P” in the P wave is an abbreviation for “parallel” in German and means “parallel”. The first wavelength light passing through the polarizing member is changed to a P wave, and the polarization state of the first wavelength light is clarified. Since the polarizing member is formed so as to transmit the P-wavelength first wavelength light, the P-wavelength first wavelength light is surely transmitted through the polarizing member and reliably passed through the first objective lens. Focused on one medium.

  An optical pickup device according to an eighth aspect is the optical pickup device according to any one of the second to seventh aspects, wherein the first wavelength light passing through the polarizing member is changed to an S wave. One wavelength light is reflected by the polarizing member and passes through the second objective lens.

  With the above configuration, the S-wavelength first wavelength light is reflected by the polarizing member, passes through the second objective lens, and is reliably collected on the first medium and another medium different from the second medium. “S” in the S wave is an abbreviation for “senkrecht” in German and means “vertical”. The first wavelength light that has passed through the polarizing member is converted to an S wave, and the polarization state of the first wavelength light is clarified. Since the polarizing member is formed so as to reflect the first wavelength light of the S wave, the first wavelength light of the S wave is reliably reflected by the polarizing member and reliably transmitted via the second objective lens. Focused on other media.

  An optical pickup device according to a ninth aspect is the optical pickup device according to any one of the second to eighth aspects, further comprising a polarization direction conversion member capable of polarizing the first wavelength light.

  With the above configuration, the first wavelength light emitted from the first light-emitting element reaches the first medium via the first objective lens, or the first medium and the second medium via the second objective lens. It is diverted to the optical path that reaches other media. By changing the polarization state of the first wavelength light using the polarization direction changing member, the first wavelength light is transmitted through or reflected by the polarizing member, for example. By transmitting or reflecting the first wavelength light through the polarizing member, the first wavelength light passes through the first objective lens to the first medium, or passes through the second objective lens to another medium. It is surely turned to the optical path to reach.

  An optical pickup device according to a tenth aspect is the optical pickup device according to the ninth aspect, wherein the polarization direction changing member is located between the first light emitting element and the polarizing member.

  By the said structure, the optical path change of the 1st wavelength light in a polarizing member is performed reliably. By positioning a polarization direction conversion member capable of polarizing the first wavelength light between the first light emitting element and the polarizing member, the first wavelength light emitted from the first light emitting element is transmitted to the polarizing member at the first wavelength. Before the light is incident, the desired polarization state is surely obtained. Since the polarization state of the first wavelength light can be determined in advance before the first wavelength light is incident on the polarizing member, the first wavelength light emitted from the first light emitting element is Thus, the light beam is reliably directed to the optical path that reaches the first medium via the first objective lens, or the optical path that reaches another medium different from the first medium and the second medium via the second objective lens.

  In an optical pickup device according to an eleventh aspect, in the optical pickup device according to the ninth or tenth aspect, a liquid crystal element capable of polarizing the first wavelength light into a P wave or an S wave is used as the polarization direction conversion member. It is characterized by that.

With the above configuration, the first wavelength light is polarized into P wave or S wave. For example, when electricity is not applied to the liquid crystal element, the P-wavelength first wavelength light incident on the liquid crystal element is emitted from the liquid crystal element as the P-wavelength first wavelength light. In this case, for example, the P-wavelength first wavelength light passes through the polarizing member, reaches the first objective lens, and is condensed on the first medium by the first objective lens. Further, for example, when electricity is applied to the liquid crystal element, the P-wavelength first wavelength light incident on the liquid crystal element is polarized into S-wavelength first wavelength light and emitted from the liquid crystal element. In this case, for example, the S-wavelength first wavelength light is reflected by the polarizing member and reaches the second objective lens, and is collected by the second objective lens on another medium different from the first medium and the second medium. The

  An optical pickup device according to a twelfth aspect is the optical pickup device according to the ninth or tenth aspect, wherein the first wavelength light can be polarized into a P wave or an S wave as the polarization direction conversion member. Is used.

  With the above configuration, the first wavelength light is polarized into P wave or S wave. For example, when the half-wave plate is not positioned in the first optical path, the P-wave first wavelength light passing through the vicinity of the half-wave plate is left as the P-wave first wavelength light. . In this case, for example, the P-wavelength first wavelength light passes through the polarizing member, reaches the first objective lens, and is condensed on the first medium by the first objective lens. Further, for example, when the half-wave plate is positioned in the first optical path, the P-wave first wavelength light incident on the half-wave plate is polarized into the S-wave first wavelength light. The light is emitted from the half-wave plate. In this case, for example, the S-wavelength first wavelength light is reflected by the polarizing member and reaches the second objective lens, and is collected by the second objective lens on another medium different from the first medium and the second medium. The

  The optical pickup device according to claim 13 is the optical pickup device according to any one of claims 1 to 12, wherein the optical pickup device has a wavelength different from the first wavelength light and a wavelength different from the second wavelength light. And a third light emitting element capable of emitting the third wavelength light.

  With the above-described configuration, the optical pickup device can support other media corresponding to the third wavelength light having a wavelength different from the first wavelength light and a wavelength different from the second wavelength light. Therefore, it is possible to provide an optical pickup device that supports various media.

  The optical pickup device according to claim 14 is the optical pickup device according to claim 13, wherein the first wavelength light is guided to an optical path passing through the first objective lens or an optical path passing through the second objective lens. By the member, the third wavelength light is guided to an optical path passing through the second objective lens.

  With the above configuration, an optical pickup device corresponding to various media of different standards is configured. When the polarizing member is installed in the optical pickup device, the first wavelength light emitted from the first light emitting element is guided to the optical path via the first objective lens. Or the 1st wavelength light radiate | emitted from the 1st light emitting element is guide | induced to the optical path which passes along a 2nd objective lens. In addition, since the polarizing member is installed in the optical pickup device, the third wavelength light emitted from the third light emitting element is guided to the optical path via the second objective lens. By installing the polarizing member in the optical pickup device, the optical pickup device can support various media.

  The optical pickup device according to a fifteenth aspect is the optical pickup device according to the fourteenth aspect, wherein the third wavelength light is reflected by the polarizing member and passes through the second objective lens.

  With the above configuration, the third wavelength light emitted from the third light emitting element is condensed on another medium by the second objective lens. The third wavelength light can be condensed on another medium by utilizing the reflection characteristic with respect to the third wavelength light provided in the polarizing member.

  The optical pickup device according to claim 16 is the optical pickup device according to any one of claims 13 to 15, wherein the third wavelength light is a standard medium different from the first medium by the second objective lens. And the light is condensed on a third medium which is a standard medium different from the second medium.

  With the above configuration, the optical pickup device is compatible with various media including the third media corresponding to the third wavelength light. The optical pickup device includes a first medium corresponding to the first wavelength light, a standard medium different from the first medium, a second medium corresponding to the second wavelength light, and a standard medium different from the first medium. The standard medium is different from the second medium, and is compatible with the third medium corresponding to the third wavelength light. For example, the first medium is a high-density recording standard medium, the second medium is a conventional standard medium, the third medium is a higher-density recording standard medium than the second medium, and is different from the second medium. Even if it is supposed to include media of the conventional standard, this optical pickup device corresponds to the first media, the second media, and the third media.

  The optical pickup device according to claim 17 is the optical pickup device according to any one of claims 1 to 12, wherein the second light emitting element has a wavelength different from the second wavelength light and the first wavelength light. And a light emitting device that emits a plurality of types of wavelength light capable of emitting a third wavelength light having a different wavelength from the second wavelength light.

  With the above configuration, an optical pickup device that can handle various media is configured, and the number of parts of the optical pickup device can be reduced. The second light emitting element is capable of emitting two or more types of light having a second wavelength light and a third wavelength light having a wavelength different from the first wavelength light and a wavelength different from the second wavelength light. Since it is configured as a light emitting element that emits light of various types of wavelengths, the optical pickup device can handle various types of media. Also, together with this, the light emitting element that can emit the second wavelength light and the light emitting element that can emit the third wavelength light are combined as one light emitting element. It will be lightened. Therefore, it is possible to provide an optical pickup device that can be used for various media and that is reduced in parts, reduced in size, reduced in thickness, and the like.

  The optical pickup device according to claim 18 is the optical pickup device according to claim 17, wherein the third wavelength light follows the second optical path which is the same optical path as the optical path followed by the second wavelength light, and The second objective lens collects light on a third medium that is a standard medium different from the first medium and a standard medium different from the second medium.

  With the above configuration, the optical pickup device is compatible with various media including the third media corresponding to the third wavelength light. The optical pickup device includes a first medium corresponding to the first wavelength light, a standard medium different from the first medium, a second medium corresponding to the second wavelength light, and a standard medium different from the first medium. The standard medium is different from the second medium, and is compatible with the third medium corresponding to the third wavelength light. For example, the first medium is a high-density recording standard medium, the second medium is a conventional standard medium, the third medium is a higher-density recording standard medium than the second medium, and is different from the second medium. Even if it is supposed to include media of the conventional standard, this optical pickup device corresponds to the first media, the second media, and the third media.

  An optical pickup device according to a nineteenth aspect is the optical pickup device according to any one of the first to eighteenth aspects, wherein the optical pickup device can be equipped in a computer that is easy to carry.

  With the above-described configuration, an optical pickup device that supports various media of different standards and can be installed in a computer that is easy to carry is configured.

  An optical disk device according to a twentieth aspect is characterized by including the optical pickup device according to any one of the first to nineteenth aspects.

  With the above configuration, reading of data from various media and writing of data to various media can be performed by an optical disc apparatus including an optical pickup device. Various media are provided in the optical disk device, and for example, data of various media is read or data is written to various media. Therefore, it is possible to provide an optical disc apparatus that can handle various media.

  As described above, according to the first aspect of the present invention, even if the standard of the first medium is different from the standard of the second medium, at least the first medium and the standard medium different from the first medium are used. An optical pickup device compatible with two media can be provided. A first light emitting element capable of emitting first wavelength light, a second light emitting element capable of emitting second wavelength light having a wavelength different from the first wavelength light, and condensing the first wavelength light on the first medium. If an optical pickup device comprising a first objective lens for focusing and a second objective lens for condensing the second wavelength light on a second medium of a standard medium different from the first medium is configured, one optical pickup device Thus, for example, at least a high-density recording standard first medium and a second standard medium different from the first medium can be supported. Therefore, it is possible to provide an optical pickup device that supports various media of different standards. In addition, a first optical path that is an optical path of the first wavelength light from the first light emitting element through the first objective lens to the first medium, and a second optical element from the second light emitting element through the second objective lens. By crossing the second optical path that is the optical path of the second wavelength light until reaching the two media, the optical pickup device can be reduced in size and thickness.

  According to the second aspect of the present invention, it is possible to configure an optical pickup device that supports various media of different standards. When the polarizing member is installed in the optical pickup device, the first wavelength light emitted from the first light emitting element is guided to the optical path via the first objective lens. Or the 1st wavelength light radiate | emitted from the 1st light emitting element is guide | induced to the optical path which passes along a 2nd objective lens. By installing the polarizing member in the optical pickup device, the optical pickup device can be adapted to various media.

  According to the invention described in claim 3, the first wavelength light emitted from the first light emitting element is condensed on the first medium by the first objective lens. Or the 1st wavelength light radiate | emitted from the 1st light emitting element is condensed by the 2nd objective lens on the other medium made into a medium different from a 1st medium, and a medium different from a 2nd medium. . The first wavelength light is condensed on the first medium or another medium different from the first medium and the second medium by utilizing the transmission characteristic or reflection characteristic for the first wavelength light included in the polarizing member. Can be made.

  According to the invention described in claim 4, it is possible to configure an optical pickup device corresponding to various media of different standards. Since the optical pickup device is equipped with a polarizing member that guides the second wavelength light to the optical path that reaches the second medium via the second objective lens, the optical pickup device can be adapted to various media.

  According to the invention of claim 5, the second wavelength light emitted from the second light emitting element is condensed on the second medium by the second objective lens. The second wavelength light can be condensed on the second medium by using the transmission characteristic of the second wavelength light included in the polarizing member.

  According to the sixth aspect of the present invention, it is possible to reduce the size / thinness of the optical pickup device that can handle various media. By positioning the polarizing member at the optical path intersection where the first optical path and the second optical path intersect, the optical layout in the optical pickup device can be made compact. Therefore, it is possible to provide a small / thin optical pickup device that can handle various media.

  According to the seventh aspect of the present invention, the P-wavelength first wavelength light is reliably condensed on the first medium through the polarizing member, via the first objective lens. The first wavelength light passing through the polarizing member is changed to a P wave, and the polarization state of the first wavelength light is clarified. Since the polarizing member is formed so as to transmit the P-wavelength first wavelength light, the P-wavelength first wavelength light is surely transmitted through the polarizing member and reliably passed through the first objective lens. Focused on one medium.

  According to the eighth aspect of the present invention, the S-wavelength first-wavelength light is reflected by the polarizing member, passes through the second objective lens, and reliably passes through the first medium and another medium different from the second medium. It is condensed to. The first wavelength light that has passed through the polarizing member is converted to an S wave, and the polarization state of the first wavelength light is clarified. Since the polarizing member is formed so as to reflect the first wavelength light of the S wave, the first wavelength light of the S wave is reliably reflected by the polarizing member and reliably transmitted via the second objective lens. Focused on other media.

  According to the ninth aspect of the invention, the first wavelength light emitted from the first light emitting element is transmitted through the first objective lens to the first medium, or through the second objective lens. It can be directed to an optical path that reaches other media different from the first media and the second media. By changing the polarization state of the first wavelength light using the polarization direction changing member, the first wavelength light is transmitted through or reflected by the polarizing member, for example. By transmitting or reflecting the first wavelength light through the polarizing member, the first wavelength light passes through the first objective lens to the first medium, or passes through the second objective lens to another medium. It is surely turned to the optical path to reach.

  According to the tenth aspect of the present invention, it is possible to reliably change the optical path of the first wavelength light in the polarizing member. By positioning a polarization direction conversion member capable of polarizing the first wavelength light between the first light emitting element and the polarizing member, the first wavelength light emitted from the first light emitting element is transmitted to the polarizing member at the first wavelength. Before the light is incident, the desired polarization state is surely obtained. Since the polarization state of the first wavelength light can be determined in advance before the first wavelength light is incident on the polarizing member, the first wavelength light emitted from the first light emitting element is transmitted by the polarizing member. The optical path reaching the first medium via the first objective lens or the optical path reaching the other medium different from the first medium and the second medium via the second objective lens is reliably directed.

  According to the eleventh aspect of the invention, the first wavelength light can be polarized into P wave or S wave. For example, when electricity is not applied to the liquid crystal element, the P-wavelength first wavelength light incident on the liquid crystal element is emitted from the liquid crystal element as the P-wavelength first wavelength light. In this case, for example, the P-wavelength first wavelength light passes through the polarizing member, reaches the first objective lens, and is condensed on the first medium by the first objective lens. Further, for example, when electricity is applied to the liquid crystal element, the P-wavelength first wavelength light incident on the liquid crystal element is polarized into S-wavelength first wavelength light and emitted from the liquid crystal element. In this case, for example, the S-wavelength first wavelength light is reflected by the polarizing member and reaches the second objective lens, and is collected by the second objective lens on another medium different from the first medium and the second medium. The

According to invention of Claim 12, 1st wavelength light can be polarized into P wave or S wave. For example, when the half-wave plate is not positioned in the first optical path, the P-wave first wavelength light passing through the vicinity of the half-wave plate is left as the P-wave first wavelength light. . In this case, the P-wavelength first wavelength light, for example, passes through the polarizing member, reaches the first objective lens, and is condensed on the first medium by the first objective lens. Further, for example, when the half-wave plate is positioned in the first optical path, the P-wave first wavelength light incident on the half-wave plate is polarized into the S-wave first wavelength light. The light is emitted from the half-wave plate. In this case, the S-wavelength first wavelength light is reflected by, for example, a polarizing member and reaches the second objective lens, and is collected by the second objective lens on another medium different from the first medium and the second medium. .

  According to the invention of claim 13, the optical pickup device is also compatible with other media corresponding to the third wavelength light having a wavelength different from the first wavelength light and a wavelength different from the second wavelength light. It becomes possible. Therefore, it is possible to provide an optical pickup device that supports various media.

  According to the fourteenth aspect of the present invention, it is possible to configure an optical pickup device corresponding to various media of different standards. When the polarizing member is installed in the optical pickup device, the first wavelength light emitted from the first light emitting element is guided to the optical path via the first objective lens. Or the 1st wavelength light radiate | emitted from the 1st light emitting element is guide | induced to the optical path which passes along a 2nd objective lens. In addition, since the polarizing member is installed in the optical pickup device, the third wavelength light emitted from the third light emitting element is guided to the optical path via the second objective lens. By installing the polarizing member in the optical pickup device, the optical pickup device can be adapted to various media.

  According to the invention described in claim 15, the third wavelength light emitted from the third light emitting element is condensed on the other medium by the second objective lens. The third wavelength light can be condensed on another medium by using the reflection characteristic of the polarizing member with respect to the third wavelength light.

  According to the sixteenth aspect of the present invention, the optical pickup device supports various media including the third media corresponding to the third wavelength light. The optical pickup device includes a first medium corresponding to the first wavelength light, a standard medium different from the first medium, a second medium corresponding to the second wavelength light, and a standard medium different from the first medium. The standard medium is different from the second medium, and is compatible with the third medium corresponding to the third wavelength light. For example, the first medium is a high-density recording standard medium, the second medium is a conventional standard medium, the third medium is a higher-density recording standard medium than the second medium, and is different from the second medium. Even if it is supposed to include media of a conventional standard, this optical pickup device corresponds to the first media, the second media, and the third media.

  According to the seventeenth aspect of the present invention, it is possible to configure an optical pickup device that can handle various types of media, and it is possible to reduce the number of parts of the optical pickup device. The second light emitting element is capable of emitting two or more types of light having a second wavelength light and a third wavelength light having a wavelength different from the first wavelength light and a wavelength different from the second wavelength light. Since it is configured as a light emitting element that emits light of various types of wavelengths, the optical pickup device can handle various types of media. Also, together with this, the light emitting element that can emit the second wavelength light and the light emitting element that can emit the third wavelength light are combined as one light emitting element. It can be made lighter and thinner. Therefore, it is possible to provide an optical pickup device that can be used for various media and that can be reduced in parts, reduced in size, reduced in thickness, and the like.

According to the invention described in claim 18, the optical pickup device supports various media including the third media corresponding to the third wavelength light. The optical pickup device includes a first medium corresponding to the first wavelength light, a standard medium different from the first medium, a second medium corresponding to the second wavelength light, and a standard medium different from the first medium. The standard medium is different from the second medium, and is compatible with the third medium corresponding to the third wavelength light. For example, the first medium is a high-density recording standard medium, the second medium is a conventional standard medium, the third medium is a higher-density recording standard medium than the second medium, and is different from the second medium. Even if it is supposed to include media of a conventional standard, this optical pickup device corresponds to the first media, the second media, and the third media.

  According to the nineteenth aspect of the present invention, it is possible to configure an optical pickup device that can accommodate various media of different standards and can be equipped in a computer that is easy to carry.

  According to the twentieth aspect of the present invention, reading of data from various media and writing of data to various media can be executed by an optical disk device including an optical pickup device. Various media are provided in the optical disk device, and for example, data of various media is read or data is written to various media. Therefore, it is possible to provide an optical disc apparatus that can handle various media.

  Embodiments of an optical pickup device according to the present invention and an optical disk device including the same will be described in detail below with reference to the drawings.

  First, a first embodiment of an optical pickup device according to the present invention and an optical disk device including the same will be described in detail with reference to FIGS.

  FIG. 1 is a schematic diagram showing a first embodiment of an optical pickup device according to the present invention and an optical disk device including the same, and FIG. 2A shows a state in which first wavelength light is irradiated onto a first medium. FIG. 2B is an explanatory diagram illustrating a state in which the second wavelength light is irradiated to the second medium, and FIG. 3A illustrates a state in which the first wavelength light is irradiated to the first medium. FIG. 3B is an explanatory diagram illustrating a state in which the third wavelength light is irradiated to the third medium.

  2A or 3A shows the first objective lens 60 (FIG. 1), the substantially side surfaces of the first mirror 58, etc., for example, the first objective lens 60 from the central portion side of the substantially disc-shaped medium. The optical axis LA1 of the second objective lens 70 and the optical axis LA2 of the second objective lens 70 are connected to each other. 1, FIG. 2 (A), FIG. 3 (A)). 2 (B) or 3 (B) shows a direction perpendicular to the media radial direction Dr on substantially side surfaces of the second objective lens 70 (FIG. 1), the aperture limiting element 69, the second mirror 68, and the like. And is a schematic view viewed from the first collimator lens 41 side substantially along the tangential direction Ds that is orthogonal to the tracking direction Df (FIGS. 1, 2B, and 3). (B)).

  Various media such as various optical disks are inserted into an optical disk device (not shown). Various optical disks 100, 200, and 300 placed in an optical disk device (not shown) are formed in a disk shape. As the disk, for example, an optical disk dedicated to data reading such as “CD-ROM”, “DVD-ROM”, “HD DVD-ROM”, “BD-ROM”, “CD-R”, “DVD-R”, Data write-once optical disks such as “DVD + R”, “HD DVD-R”, “BD-R”, “CD-RW”, “DVD-RW”, “DVD + RW” (registered trademark), “DVD-RAM” , “HD DVD-RW”, “HD DVD-RAM”, “BD-RE”, and other types of optical disks capable of data writing / erasing and data rewriting.

  Further, examples of the disc include an optical disc (not shown) in which signal surfaces are provided on both sides of the disc and data writing / erasing and data rewriting are possible. Further, examples of the disk include an optical disk (not shown) provided with a two-layer signal surface and capable of data writing / erasing and data rewriting. Also, for example, an “HD DVD” optical disc (not shown) provided with a three-layer signal surface and capable of data writing / erasing and data rewriting is also included. In addition, for example, a “Blu-ray Disc” optical disc (not shown) provided with a four-layer signal surface and capable of data writing / erasing and data rewriting is also included.

  The signal unit 150 of the first optical disc 100 (FIGS. 2A and 3A) is formed of a metal layer such as a metal thin film, for example. Information, data, and the like are recorded on the signal surface portion 150 of a layer formed of a metal thin film or the like. Further, the signal portion 250 of the second optical disc 200 (FIG. 2B) is also formed of a metal layer such as a metal thin film, for example. Information, data, and the like are recorded on the signal surface portion 250 of a layer formed of a metal thin film or the like. Further, the signal portion 350 of the third optical disc 300 (FIG. 3B) is also formed of a metal layer such as a metal thin film, for example. Information, data, and the like are recorded on the signal surface portion 350 of a layer formed of a metal thin film or the like.

  The optical disc apparatus is compatible with the various discs. An optical disk device is used to reproduce data such as information recorded on various optical disks 100, 200, and 300. In addition, data such as information is recorded on various optical discs 100, 200, and 300 using an optical disc device.

  In the optical disc 100, 200, 300 in which information such as data can be recorded in the optical disc apparatus, a groove (for storing data / information in the signal units 150, 250, 350 of the optical disc 100, 200, 300) (Not shown) is provided. A groove means an elongated dent. When the disk-shaped optical disc 100, 200, 300 is viewed in plan, the groove is formed in a substantially spiral shape. When the optical discs 100, 200, and 300 are irradiated with laser light, when the optical discs 100, 200, and 300 are viewed from the signal surface portions 150, 250, and 350 that are irradiated with the laser light, the grooves are spiral. Has been. Since the groove is very small, the groove is not visible. In FIG. 2 or FIG. 3, for convenience, the signal units 150, 250, and 350 of the optical discs 100, 200, and 300 are shown using broken lines.

The optical disk will be described. “CD” is an abbreviation for “Compact Disc” (trademark). “DVD” (registered trademark) is an abbreviation of “Digital Versatile Disc”. Further, “ROM” in “CD-ROM”, “DVD-ROM” and “HD DVD-ROM” is an abbreviation of “Read Only Memory”. “BD-ROM” is an abbreviation for “Blu-ray Disc-ROM”. “CD-ROM”, “DVD-ROM”, “HD
“DVD-ROM” and “BD-ROM” are exclusively used for reading data / information. In addition, “R” in “CD-R”, “DVD-R”, “DVD + R”, and “HD DVD-R” is an abbreviation of “Recordable”. “BD-R” is an abbreviation for “Blu-ray Disc-R”. “CD-R”, “DVD-R”, “DVD + R”, “HD DVD-R”, and “BD-R” can write data / information. “RW” in “CD-RW”, “DVD-RW”, “DVD + RW”, and “HD DVD-RW” is an abbreviation of “Re-Writable”. “BD-RE” is an abbreviation for “Blu-ray Disc-RE”. “CD-RW”, “DVD-RW”, “DVD + RW”, “HD DVD-RW”, and “BD-RE” can be rewritten data / information. Further, “RAM” in “DVD-RAM” and “HD DVD-RAM” is an abbreviation for “Random Access Memory”. “DVD-RAM” and “HD DVD-RAM” can read / write / erase data / information.

  “HD DVD” (registered trademark) is an abbreviation for “High Definition DVD”. The “HD DVD” is compatible with the conventional DVD series and has a larger storage capacity than the conventional DVD series disks. In the conventional CD, an infrared laser is used. In addition, a red laser is used for a conventional DVD. However, when data / information recorded on the “HD DVD” optical disc 300 (FIG. 3B) is read out or when data / information is written on the “HD DVD” optical disc 300, a blue-violet laser is used. It is done. “Blu-ray” means a blue-violet laser employed to realize high-density recording, compared to a red laser used for conventional signal reading and writing.

  Since the "DVD" standard optical disc 300 and the "HD DVD" standard optical disc 300 are compatible with many common parts, in this specification, the "DVD" standard optical disc 300 and For the sake of convenience, the same reference numerals are used to describe the “HD DVD” standard optical disc 300.

  As shown in FIGS. 2 and 3, the thicknesses 210t and 220t of the substrates 210 and 220 of the CD-series optical disc 200 (FIG. 2B) and the substrates 310 of the DVD-series optical disc 300 (FIG. 3B). , 320 is different from the thicknesses 310t, 320t. In the CD-series optical disc 200 (FIG. 2B), the thickness 210t of the first substrate 210 through which the laser beam is transmitted is, for example, back-to-back with respect to the first substrate 210. Is thicker than 220t. On the other hand, the DVD optical disc 300 (FIG. 3B) has a thickness 310t of the first substrate 310 and a thickness 320t of the second substrate 320 that is back-to-back with respect to the first substrate 310, for example. Are approximately equal. The thickness 210t of the first substrate 210 in the CD-series optical disc 200 (FIG. 2B) is, for example, approximately 1.1 mm (millimeters), and the thickness 220t of the second substrate 220, the so-called layer 220, is, for example, approximately 0.1 mm. It is said. In addition, the thickness 310t of the first substrate 310 and the thickness 320t of the second substrate 320 in the DVD-series optical disc 300 (FIG. 3B) are both approximately 0.6 mm.

  Further, the thicknesses 310t and 320t on the substrates 310 and 320 of the DVD optical disc 300 (FIG. 3B) and the substrates 110 and 120 of the Blu-ray Disc optical disc 100 (FIG. 3A), respectively. The thickness is different from 110t and 120t. In the DVD-series optical disc 300, the thickness 310t of the first substrate 310 and the thickness 320t of the second substrate 320 that is back-to-back with respect to the first substrate 310 are substantially equal. On the other hand, in the Blu-ray Disc series optical disc 100, the thickness 110t of the first substrate 110 through which the laser light is transmitted is, for example, the thickness of the second substrate 120 that is back-to-back with respect to the first substrate 110. Thinner than 120t. In the Blu-ray Disc series optical disc 100, the thickness 110t of the first substrate 110 is approximately 0.1 mm, and the thickness 120t of the second substrate 120 is approximately 1.1 mm.

  Further, the thicknesses 110t and 120t of the respective substrates 110 and 120 of the Blu-ray Disc series optical disc 100 (FIG. 2A) and the substrates 210 and 220 of the CD series optical disc 200 (FIG. 2B). It is different from the thicknesses 210t and 220t. In the Blu-ray Disc series optical disc 100, the thickness 110t of the first substrate 110 through which the laser beam is transmitted is thinner than the thickness 120t of the second substrate 120 that is back-to-back with respect to the first substrate 110, for example. . On the other hand, in the CD-series optical disc 200, the thickness 210t of the first substrate 210 through which the laser beam is transmitted is, for example, the thickness of the second substrate 220 so-called layer 220 that is back-to-back with the first substrate 210. Thicker than 220t.

Also, the track pitch and the like in the signal section 250 of the CD-series optical disc 200 (FIG. 2B), the track pitch and the like in the signal section 350 of the DVD-series optical disc 300 (FIG. 3B), and the Blu-ray Disc The track pitch and the like in the signal unit 150 of the optical disc 100 of the series (FIGS. 2A and 3A) are different from each other. As described above, the optical discs 100 (FIG. 2A, FIG. 3A), 200 (FIG. 2B), and 300 (FIG. 3B) have different standards. It is said that.

  In this specification, the “Blu-ray Disc” standard optical disc 100 is defined as the first medium 100 for convenience. Further, the “CD” standard optical disc 200 is defined as the second medium 200 for convenience. For convenience, the second medium 200 is another medium 200. Further, the “HD DVD” standard or “DVD” standard optical disc 300 is defined as the third medium 300 for convenience. For convenience, the third medium 300 is another medium 300.

  The optical pickup device 1 is adapted to reproduce data recorded on the various optical discs and record data on the writable or rewritable optical discs. An optical pickup or an optical pickup unit is abbreviated as “OPU”, for example. The OPU 1 is compatible with CD media, DVD media, and Blu-ray Disc media. As described above, the OPU 1 corresponds to a plurality of media.

  The focusing detection method of the condensing spot S1 (FIGS. 2A, 3A) and S3 (FIG. 3B) in the OPU 1 is a detection method based on the differential astigmatism method. . The differential astigmatism method is, for example, a method for detecting the displacement of the focused spots S1 and S3 by detecting a point image distortion formed by an optical system having astigmatism. The OPU 1 (FIG. 1) is an OPU 1 provided with an optical system based on a differential astigmatism method.

  Further, the tracking detection method of the condensing spot S1 (FIGS. 2A, 3A), S2 (FIG. 2B), and S3 (FIG. 3B) in the OPU 1 is a differential push-pull. And a detection method based on the phase difference method. The differential push-pull method is, for example, a method of detecting the displacement of the focused spots S1, S2, and S3 by using a main beam for reading and writing data and two sub beams for detecting a positional deviation correction signal. . For example, tracking detection is performed based on the phase difference signal detected by the quadrant photodetector 90A (FIG. 1). The phase difference method is, for example, a detection method based on a phase difference signal detected by a quadrant photodetector.

  Focus means focus and focus. Focusing means focusing or focusing. In addition, tracking refers to the use of light to form minute pits (holes, dents) or grooves (grooves) provided in the signal portions 150, 250, 350 of the optical discs 100, 200, 300 (FIGS. 2 and 3). , Wobbling (meandering) and the like are tracked and the position of the orbit drawn in a substantially spiral shape is determined. “Tilt” refers to the objective lenses 60 and 70 (FIGS. 2 and 3) emitted from the signal surface portions 150, 250, and 350 of the optical discs 100, 200, and 300 and the light emitting elements 10, 20, and 30 (FIG. 1). Means an angular deviation with respect to the optical axes LA1 and LA2 of the laser beam that has passed through. Further, in this specification, the focus direction Df (FIGS. 1 to 3), the tracking direction Dr or the disk radial direction Dr (FIGS. 1 to 3), and the tilt direction Dt (FIGS. 2B and 3B) Is defined for the convenience of describing the OPU.

Laser light having an output value of 0.2 to 500 mW (milliwatts), specifically 3 to 300 mW, is emitted from each of the light emitting elements 10, 20, and 30 (FIG. 1). For example, when the laser beam has an output value of less than 0.2 mW, the amount of the laser beam reflected after being irradiated on each of the optical discs 100, 200, and 300 (FIGS. 2 and 3) is insufficient. Each optical disc 100, 200, 3
When reproducing each data of 00 or the like, a laser beam having an output value of several to several tens of mW, for example, about 3 to 10 mW is sufficient. When writing each data etc. to each optical disk 100, 200, 300, the laser beam of the output value of several dozen-several hundred mW is required. For example, when writing each data etc. to each optical disk 100, 200, 300 at high speed, a laser beam with a high output value of 300 mW or 500 mW may be required.

  First, the optical path of the laser emitted from the first light emitting element 10 (FIG. 1) will be described. A current flows from the laser driver 9 to the first light emitting element 10, and the first light emitting element 10 outputs laser light having the first wavelength. The state in which the laser beam of the first wavelength is output from the first light emitting element 10 will be described in detail. A current flows from the laser driver 9 to the light emitting element 10 for “Blu-ray Disc” or “HD DVD”. The laser light having a wavelength corresponding to the “Blu-ray Disc” or “HD DVD” disc is output from the “Blu-ray Disc” or “HD DVD” light emitting element 10. The first light emitting element 10 is a laser for “HD DVD” and “Blu-ray Disc” capable of emitting blue-violet laser light having a wavelength of about 350 to 450 nm (nanometer) and a reference wavelength of about 405 nm, for example. It is a diode. The laser diode is abbreviated as “LD”. For example, the first light emitting element 10 is the first LD 10, the second light emitting element 20 is the second LD 20, and the third light emitting element 30 is the third LD 30.

  The laser driver is called “LDD” or the like. “LDD” is an abbreviation for “LD driver”. The LDD 9 includes a laser driving circuit that drives the first LD 10 to emit laser light having the first wavelength from the first LD 10. The LDD 9 includes a laser driving circuit that drives the second LD 20 to emit laser light having the second wavelength from the second LD 20. The LDD 9 includes a laser driving circuit that drives the third LD 30 to emit a laser beam having the third wavelength from the third LD 30. The LDD 9 is configured as, for example, a standardized LDD 9 that can be used in common with other OPUs.

  The optical path until the laser light emitted from the first LD 10 is applied to the “Blu-ray Disc” standard optical disc 100 will be described. A current is supplied from the LDD 9 to the first LD 10, and the “Blu-ray Disc” standard optical disc 100 (FIGS. 2A and 3) is generated by blue-violet laser light having a wavelength of 350 to 450 nm emitted from the first LD 10. (A)), information is recorded, or information recorded on the “Blu-ray Disc” standard optical disc 100 is reproduced. The first LD 10 (FIG. 1) is configured as a special LD.

  When the LD emits light, heat is generated from the LD. The temperature of the LD itself changes due to heat generated from the LD that emits light. The oscillation wavelength in the LD depends on the temperature. For this reason, when the temperature of the LD itself changes, the wavelength of the laser light emitted from the LD changes. It is preferable that the wavelength of the laser light be maintained at a substantially constant wavelength without being changed as much as possible.

Diffused light is emitted from the first LD 10. Diffused light means light from a light source that diffuses and irradiates light in various directions. The first wavelength laser beam of the diffused light output from the first LD 10 passes through the optical path L1a and the first DOE 11 for “Blu-ray Disc” or “HD DVD”. DOE (Diffractive Optical Element) means a diffractive optical element that changes the traveling direction of light by utilizing a light diffraction phenomenon. The DOE is a diffractive optical element in which a special grating and a half-wave plate are configured as one. A grating means a diffraction grating. The diffraction grating divides the laser light emitted from the LD into several parts by utilizing light diffraction. More specifically, the diffraction grating plays a role of at least dividing the laser light emitted from the LD into one main beam and two sub beams using light diffraction. Grating is also called GRT. The half-wave plate plays a role of changing the polarization direction of linearly polarized light. The half wave plate is also called HWP. The half-wave plate is also called a 1 / 2λ (lambda) plate. For example, the first diffractive optical element 11 is the first DOE 11, the second diffractive optical element 21 is the second DOE 21, and the third diffractive optical element 31 is the third DOE 31. When the laser beam having the first wavelength passes through the first DOE 11, the laser beam having the first wavelength becomes a linearly polarized P wave.

  “P” in the P wave is an abbreviation for “parallel” in German and means “parallel”. In addition, “S” of S wave with respect to P wave is an abbreviation of “senkrecht” in German and means “vertical”. Depending on the design / specifications of the OPU, the P wave and the S wave are used properly. The linearly polarized P-wavelength first-wavelength laser light transmitted through the first DOE 11 is incident on the polarization member 35 through the optical path L1a. In the polarizing member 35, the polarizing member 35 is configured to transmit the P wave substantially straight and transmit it, and to reflect the S wave substantially at a right angle. The polarizing member 35 includes a special film 35c that forms a dichroic filter. Dichroic means having two hues. The dichroic filter is abbreviated as a dichroic filter or the like. Further, the polarizing members 25, 35, and 40 are also referred to as, for example, a dichroic prism or a polarizing beam splitter depending on the use site and the usage method.

  The polarization beam splitter is provided on the optical path of the laser beam so that the laser beam emitted from the LD does not emit astigmatism in the laser beam irradiated to the optical disk when passing through the polarization beam splitter. It is done. Astigmatism means, for example, a focus position shift. The polarization beam splitter is abbreviated as PBS. “PBS” is an abbreviation for “polarized beam splitter” or “polarizing beam splitter”. For example, the first polarizing member 40 is the first PBS 40, the second polarizing member 25 is the second PBS 25, and the third polarizing member 35 is the third PBS 35.

  The PBS 35 includes a first member 35a having a substantially triangular prism shape, a second member 35b having a substantially triangular prism shape fitted to the first member 35a, and a special film 35c between the first member 35a and the second member 35b. It is configured as a provision. The substantially triangular prism-shaped first member 35a and the substantially triangular prism-shaped second member 35b are combined to form a substantially cubic PBS 35 having a special film 35c. A special film 35 c is provided between the first member 35 a constituting the PBS 35 and the second member 35 b constituting the PBS 35. A special film 35 c is formed in the PBS 35. In the PBS 35, there is provided a special film 35c that allows the linearly polarized P wave to travel substantially straight and transmits, and reflects the linearly polarized S wave at a substantially right angle.

  As a result, the linearly polarized P-wave laser light incident on the PBS 35 travels substantially straight, passes through the PBS 35 and is emitted from the PBS 35. Further, the linearly polarized S-wave laser light incident on the PBS 35 is reflected substantially at right angles in the PBS 35, passes through the PBS 35, and is emitted from the PBS 35. Examples of the PBS 35 provided with a special film 35c inside include a PBS prism manufactured by Tamron. Special films are also called dichroic films. The dichroic film is abbreviated as a dichroic film. The linearly polarized P-wavelength first-wavelength laser light that has passed through the first DOE 11 passes through the PBS 35 substantially straight, and enters a liquid crystal element 37 that serves as a polarization direction conversion member 37.

The first-wavelength laser light transmitted substantially straight through the PBS 35 passes through the liquid crystal element 37 through the optical path L1c. The liquid crystal element 37 is configured as an active wavelength plate whose polarization state can be switched by voltage ON / OFF. “Liquid crystal” means a substance in an intermediate state between a solid and a liquid. The liquid crystal material has fluidity like a liquid as a whole, but has regularity of a structure similar to a crystal, and has optical anisotropy. The liquid crystal element is also called, for example, an LCD. “LCD” is an abbreviation of “liquid crystal device” or “liquid crystal display”, for example.

  When data of the “Blu-ray Disc” standard optical disc 100 (FIGS. 2A and 3A) is reproduced or when data is recorded on the “Blu-ray Disc” standard optical disc 100 In addition, no electricity flows through the LCD 37 (FIG. 1), and the LCD 37 is not energized. When the LCD 37 is not energized, the linearly polarized P-wave first wavelength laser light incident on the LCD 37 is emitted from the LCD 37 as a linearly polarized P-wave first wavelength laser light without changing the polarization state. The The linearly polarized P-wave first wavelength laser beam transmitted through the LCD 37 reaches the PBS 40 through the optical path L1c.

  The PBS 40 includes a substantially triangular prism-shaped first member 40a, a substantially triangular prism-shaped second member 40b fitted to the first member 40a, and a special film 40c between the first member 40a and the second member 40b. It is configured as a provision. The substantially triangular prism-shaped first member 40a and the substantially triangular prism-shaped second member 40b are combined to form a substantially cubic PBS 40 having a special film 40c. A special film 40 c is provided between the first member 40 a constituting the PBS 40 and the second member 40 b constituting the PBS 40. A special film 40 c is formed in the PBS 40. In the PBS 40, there is provided a special film 40c that allows the linearly polarized P-wave first wavelength laser light to pass substantially straight and transmits, and reflects the linearly polarized S-wave first wavelength laser light at a substantially right angle. More specifically, the linearly polarized P wave of the first wavelength laser beam for “Blu-ray Disc” having a blue-violet wavelength of about 350 to 450 nm is passed through the PBS 40 in a straight line, and the wavelength of about 350 to 450 nm is transmitted. A special polarizing film 40c for reflecting the linearly polarized S wave of the first wavelength laser beam for “HD DVD” having a blue-violet color at a substantially right angle is provided.

  As a result, the linearly polarized P-wavelength first-wavelength laser light incident on the PBS 40 travels substantially straight, passes through the PBS 40 and is emitted from the PBS 40. Further, the linearly polarized S-wavelength first-wavelength laser light incident on the PBS 40 is reflected substantially at right angles in the PBS 40, passes through the PBS 40, and is emitted from the PBS 40.

  As described above, the coating 40c provided in the PBS 40 allows the linearly polarized P-wave first wavelength laser light to travel substantially straight and transmits it, and reflects the linearly polarized S-wave first wavelength laser light at a substantially right angle. 40c. The coating 40c is a special coating 40c that allows the second wavelength laser beam to pass through substantially straight. Further, the coating 40c is a special coating 40c that allows the linearly polarized P-wave third-wavelength laser light to pass substantially straight through and reflects the linearly-polarized S-wave third-wavelength laser light at a substantially right angle. Examples of the PBS 40 provided with a special film 40c therein include a PBS prism manufactured by Tamron Co., Ltd. The linearly polarized P-wavelength first-wavelength laser light transmitted through the LCD 37 passes through the optical path L1c, travels substantially straight through the PBS 40, and enters the first collimator lens 41 through the optical path L1d.

  The diffused first wavelength laser light that travels substantially straight through the PBS 40 passes through the optical path L1d and passes through the first collimator lens 41 for “Blu-ray Disc”. The collimator lens emits light incident on the lens from the LD side as parallel light or substantially parallel light. Parallel light means light that travels in parallel without any rays spreading. The collimator lens is also called, for example, a collimator lens. The collimator lens is abbreviated as “CL” or “COL”.

The first CL 41 is fixed to a holding member 42 that holds the CL 41. The holding member 42 is attached to a guide member 43 that enables the holding member 42 to which the first CL 41 is attached to move along the optical path L1d extending in the optical axis direction of the first CL 41. The guide member 43 is attached to a pedestal 44 provided with a motor (not shown) for driving the guide member 43 and the like. The pedestal 44 is attached to the housing 7A. The first CL41;
An expander unit 45 that includes a holding member 42, a guide member 43, and a pedestal 44 is configured in the housing 7 </ b> A of the OPU 1.

  An expander unit in this specification is a movable unit that changes laser light to a required size. For example, a movable motor (not shown) is used, and the holding member 42 including the first CL 41 moves on the guide member 43 along the optical path L1d extending in the optical axis direction of the first CL 41. The single wavelength laser beam is varied to a required size. For example, when data is recorded on a Blu-ray Disc standard optical disc 100 having a plurality of signal layers, or when data recorded on a Blu-ray Disc standard optical disc 100 having a plurality of signal layers is reproduced. The beam expander unit 45 having the first CL 41 is required.

  Also, for example, the thicknesses 110t and 120t of the substrates 110 and 120 of the “Blu-ray Disc” optical disc 100 (FIG. 3A) and the “HD DVD” series optical disc 300 (FIG. 3B) The thicknesses 310t and 320t of the substrates 310 and 320 are different. In the optical disc 100 for “Blu-ray Disc”, the thickness 110 t of the first substrate 110 through which the laser beam is transmitted is, for example, a thickness 120 t of the second substrate 120 that is back-to-back with respect to the first substrate 110. Thinner than. On the other hand, in the “HD DVD” series optical disc 300, the thickness 310 t of the first substrate 310 is substantially equal to the thickness 320 t of the second substrate 320 that is back-to-back with respect to the first substrate 310, for example. . Further, in the “Blu-ray Disc” optical disc 100 and the “HD DVD” series optical disc 300, the signal portions 150, 350 of the optical discs 100, 300 on the optical axes LA1, LA2 along the focus direction Df. The focal positions of the spots S1 and S3 of the laser beam irradiated and formed on are different. In addition, the working distance WDb of the first objective lens 60 with respect to the optical disc 100, so-called working distance WDb, is different from the working distance WDd of the second objective lens 70 with respect to the optical disc 300, so-called working distance WDd.

  Correspondingly, the beam expander unit 45 provided with the first CL 41 (FIG. 1) is required for the OPU 1 in order to irradiate and form the high-precision focused spots S1, S3 on the various optical discs 100, 300, etc. It becomes. As described above, the OPU 1 includes the beam expander unit 45 that changes the laser beam to a predetermined size. The beam expander unit 45 including the CL 41 is configured as a beam expander unit (none of which is not shown) including the CL 41 and a pair of beam expander lenses. By installing the beam expander unit 45 including the CL 41 in the OPU 1, the number of parts of the OPU 1 is reduced and the OPU 1 can be reduced in size and thickness. The P-wavelength first-wavelength laser light that has passed through the first CL 41 of the beam expander unit 45 becomes parallel light, passes through the optical path L1d, and reaches a polarizing mirror 48, a so-called dichroic mirror 48.

  For example, approximately 92 to 98% of the linearly polarized P-wave first wavelength laser light irradiated on the front side surface 48a of the first dichroic mirror 48 through the optical path L1d is substantially triangular prism-shaped first dichroic mirror 48. The light is reflected by the front side surface 48 a so as to be slightly sharper than a right angle, and travels toward the first quarter-wave plate 57 along the optical path L 1 e. Further, for example, approximately 2 to 8% of the linearly polarized P-wave first wavelength laser light irradiated on the front side surface 48a of the first dichroic mirror 48 through the optical path L1d is substantially triangular prism-shaped first dichroic mirror. An obtuse angle from the back side surface 48b of the substantially triangular prism-shaped first dichroic mirror 48 which is bent at an obtuse angle from the front surface 48a of the 48, enters the first dichroic mirror 48, passes through the first dichroic mirror 48, and passes through the first dichroic mirror 48. Then, the light is bent and emitted so as to travel toward the first light receiving element 50 along the optical path L1g.

  More specifically, approximately 93 to 97% of the linearly polarized P-wave first wavelength laser light irradiated on the front side surface 48a of the first dichroic mirror 48 through the optical path L1d is approximately triangular prism-shaped first. The light is reflected by the front side surface 48 a of the dichroic mirror 48 so that the angle is slightly sharper than the right angle, and travels toward the first quarter wave plate 57 along the optical path L 1 e. In addition, approximately 3 to 7% of the linearly polarized P-wave first wavelength laser light irradiated to the front side surface 48a of the first dichroic mirror 48 through the optical path L1d is substantially triangular prism-shaped first dichroic mirror 48. It is bent from the front side surface 48a to have an obtuse angle, enters the first dichroic mirror 48, passes through the first dichroic mirror 48, and becomes an obtuse angle from the back side surface 48b of the substantially triangular prism-shaped first dichroic mirror 48. The light is then bent and emitted, and travels along the optical path L1g toward the first light receiving element 50.

  The dichroic mirror 48 includes a special film 48c that forms a dichroic filter. A dichroic film 48 c is formed on the front side surface 48 a of the first dichroic mirror 48. The dichroic mirror is abbreviated as a dichroic mirror or the like.

  Reflection of linearly polarized P-wave first wavelength laser light on the first dichroic mirror 48 when linearly polarized P-wave first wavelength laser light is applied to the special film 48 c on the front side surface 48 a of the first dichroic mirror 48. When the amount is smaller than 92%, for example, when the transmission amount of the first wavelength laser light of the linearly polarized P wave in the first dichroic mirror 48 is larger than 8%, for example, the optical disc 100 (FIG. 2 (A), In FIG. 3A, the amount of light necessary for irradiating the first wavelength laser beam is insufficient.

  More specifically, the linearly polarized light in the first dichroic mirror 48 when the first wavelength laser light of the linearly polarized P wave is applied to the special film 48c on the front side surface 48a of the first dichroic mirror 48 (FIG. 1). When the reflection amount of the P-wavelength first laser beam is less than 93%, that is, when the transmission amount of the first-wavelength laser beam of the linearly polarized P-wave in the first dichroic mirror 48 is more than 7%, the optical disk 100 (FIG. 2 (A), FIG. 3 (A)) lacks the amount of light necessary to irradiate the first wavelength laser beam.

  The first wavelength of the linearly polarized P wave in the first dichroic mirror 48 when the first wavelength laser beam of the linearly polarized P wave is applied to the special film 48c on the front side surface 48a of the first dichroic mirror 48 (FIG. 1). When the amount of reflection of laser light is larger than 98%, for example, when the amount of transmission of the first wavelength laser light of the linearly polarized P wave in the first dichroic mirror 48 is smaller than 2%, for example, the first light receiving element The amount of received light of the first wavelength laser beam required for 50 is insufficient.

  More specifically, when the first wavelength laser beam of the linearly polarized P wave is applied to the special film 48c on the front side surface 48a of the first dichroic mirror 48, the first of the linearly polarized P wave in the first dichroic mirror 48 is applied. When the reflection amount of the one-wavelength laser light is larger than 97%, that is, when the transmission amount of the first-wavelength laser light of the linearly polarized P wave in the first dichroic mirror 48 is smaller than 3%, the first light receiving element The amount of received light of the first wavelength laser beam required for 50 is insufficient.

Reflection of linearly polarized P-wave first wavelength laser light on the first dichroic mirror 48 when linearly polarized P-wave first wavelength laser light is applied to the special film 48 c on the front side surface 48 a of the first dichroic mirror 48. When the amount is, for example, 95%, that is, when the transmission amount of the first-wavelength laser light of the linearly polarized P wave in the first dichroic mirror 48 is, for example, 5%, the optical disc 100 (FIG. 2 (A), 3A is irradiated with sufficient laser light, and appropriate laser light required for the first light receiving element 50 (FIG. 1) is irradiated. Therefore, it is preferable that the OPU 1 is equipped with the first dichroic mirror 48 having such characteristics.

  The dichroic film 48c of the dichroic mirror 48 reflects most of the “Blu-ray Disc” laser light (first wavelength laser light) of linearly polarized P-wave having a wavelength of about 350 to 450 nm. When a first wavelength laser beam having a wavelength of 350 to 450 nm of linearly polarized P wave is applied to the first dichroic mirror 48, the first dichroic mirror 48 is mostly the first wavelength laser beam having a wavelength of 350 to 450 nm. The first wavelength laser beam having a wavelength of 350 to 450 nm is transmitted. Examples of the dichroic mirror 48 in which a special film 48c is provided on the surface 48a include Tamron Co., Ltd .: dichroic mirror, dichroic prism, and the like.

  The light enters the first dichroic mirror 48 from the front side surface 48 a of the substantially triangular prism-shaped first dichroic mirror 48, passes through the first dichroic mirror 48, and exits from the back side surface 48 b of the first triangular dichroic mirror 48. The part of the first-wavelength laser light thus made reaches the first light receiving element 50 through the optical path L1g. The first light receiving element 50 is configured as a front monitor diode to which a part of the laser light is irradiated. The front monitor diode is abbreviated as “FMD”. The FMD 50 monitors the laser light output from the LD 10 and applies feedback for controlling the LD 10.

  Most of the first-wavelength laser light reflected from the front side surface 48a of the substantially triangular prism-shaped first dichroic mirror 48 so as to be a little sharper than a right angle passes through the optical path L1e and reaches the first quarter-wave plate 57. . The quarter-wave plate changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. The linearly polarized light is circularly polarized, and the laser light between the quarter-wave plate and the optical disk is circularly polarized. For example, even if the optical disk is poor, data recording / recording on the optical disk is possible. The playback operation is performed normally. In addition, the linearly polarized light is circularly polarized, and the laser light between the quarter-wave plate and the optical disk is circularly polarized, thereby improving characteristics when data is written / reproduced to / from the optical disk. To do. The quarter wavelength plate is also called a quarter λ plate. The quarter-wave plate is abbreviated as “QWP”.

  The optical path L1e from the first dichroic mirror 48 through the first OBL 60 without the first QWP 57 being positioned in the optical paths L1a, L1c, L1d from the first LD 10 to the first dichroic mirror 48 or When the first QWP 57 (FIG. 1) is positioned in any one of the optical paths L1e and L1f in L1f (FIG. 2A, FIG. 3A), for example, via the first dichroic mirror 48 It is easy to avoid that some of the first wavelength laser beams adversely affect the first FMD 50.

  The linearly polarized P-wavelength first wavelength laser light that has passed through the optical path L1e and transmitted through the first QWP 57 becomes circularly polarized light. The first-wavelength laser light of linearly polarized P wave becomes, for example, right-handed circularly polarized light in the first QWP 57. Here, the circularly polarized light in a right-turned state is referred to as, for example, forwardly polarized circularly polarized light.

The first-wavelength laser light that has passed through the optical path L1e and passed through the first QWP 57 and turned into right-handed circularly polarized light is the upper side of the housing base wall reference portion 7h (FIGS. 2A and 3A). Is applied to the first reflective mirror 58 for reflecting the first wavelength light. The first reflective mirror 58 is provided with a coating 58a that substantially totally reflects the laser light. Therefore, the laser beam applied to the reflective mirror 58 is substantially totally reflected. The mirror is abbreviated as “MR”, for example. As a reflective mirror in which the film | membrane which substantially reflects light totally was formed, the Nitto Kogyo company make: total reflection mirror etc. are mentioned, for example.

  The first wavelength laser beam that has passed through the optical path L1e (FIG. 1) and passed through the first QWP 57 and turned into right-handed circularly polarized light is a reflective MR 58 for “Blu-ray Disc” (FIG. 2 (A), 3A is reflected at a substantially right angle, passes through the first objective lens 60 through the optical path L1f. The right-turn circularly polarized first wavelength laser light that is parallel light becomes convergent light by the first objective lens 60 having a numerical aperture of about 0.85, and is a signal portion 150 of the optical disc 100 of “Blu-ray Disc” standard. Is irradiated. The objective lens plays a role of condensing the laser light emitted from the LD onto the optical disk. The objective lens is abbreviated as “OBL”. The numerical aperture refers to the product of the sine of the angle at which the effective radius (incident pupil radius) of the objective lens is viewed from an object point in the optical instrument and the refractive index of the medium on the incident side. The numerical aperture (Numerical Aperture) is abbreviated as “NA”. The numerical aperture is used to express the performance of the objective lens. The convergent light is, for example, the reverse of the diffused light, and means light in which the light rays are brought close to each other, for example.

  When the focus servo of the first OBL 60 mounted on the lens holder (not shown) is performed on the optical disc 100, the lens holder including the first OBL 60 is moved along the focus direction Df. Further, when tracking servo of the first OBL 60 mounted on a lens holder (not shown) is performed on the optical disc 100, the lens holder including the first OBL 60 is moved along the tracking direction Dr. Further, when tilt control of the first OBL 60 mounted on the lens holder is performed with respect to the optical disc 100, the lens holder including the first OBL 60 is swung along the tilt direction.

  The lens holder equipped with the first OBL 60 is driven using a plurality of wires (not shown). More specifically, the lens holder is supported by an even number of suspension wires (not shown) such as four or six, and the even number of suspension wires, for example, the focus direction Df, tracking direction Dr, tilt It is driven substantially along any one direction or all directions among the directions. Further, a second OBL 70 is mounted on a lens holder (not shown) adjacent to the first OBL 60 (FIG. 1). The second OBL 70 is arranged in parallel to the outside of the first OBL 60 substantially along the disk radial direction Dr with respect to the first OBL 60 positioned substantially on the center side of the disk of the housing 7A constituting the OPU 1. Further, the optical axis LA1 of the first OBL 60 and the optical axis LA2 of the second OBL 70 are located on a virtual line substantially extending along the disk radial direction Dr so-called tracking direction Dr extending from the center of the disk toward the outer periphery of the disk. To do.

  The first wavelength laser beam of the diffused light emitted from the first LD 10 is converted into a linearly polarized P wave by the first DOE 11 in the optical path L1a, changed from the diffused light to the parallel light by the first CL 41 in the optical path L1d, and the optical path L1e. From the linearly polarized P wave to the right-handed circularly polarized light by the first QWP 57 and converged light by the first OBL 60 in the optical path L1f (FIG. 2 (A), FIG. 3 (A)), and “Blu-ray Disc” The light is condensed on the signal unit 150 of the standard optical disc 100. The laser beam of the first wavelength follows the forward path in this way and is focused on the “Blu-ray Disc” standard optical disc 100 as the first medium 100.

  Next, the return path of the first wavelength laser beam reflected on the “Blu-ray Disc” standard optical disc 100 will be described. When the first wavelength laser light is reflected by the signal unit 150 of the “Blu-ray Disc” standard optical disc 100, the clockwise circularly polarized first wavelength laser light becomes counterclockwise circularly polarized light. Here, the circularly polarized light that is turned left is called, for example, the circularly polarized light in an inverted state. The left-turn circularly polarized first-wavelength laser light becomes diffused light, returns through the optical path L1f, and reaches the first OBL 60. The left-handed circularly polarized first wavelength laser light that is diffused light is converted into parallel light by the first OBL 60. The left-turn circularly polarized first wavelength laser light that passes through the first OBL 60 and returns to the optical path L1f reaches the first reflective MR 58.

  The left-turn circularly polarized first-wavelength laser light reflected by the first reflective MR 58 returns to the first QWP 57 through the optical path L1e (FIG. 1). When the first wavelength laser beam returns through the optical path L1e and passes through the first QWP 57, the left-turn circularly polarized first wavelength laser beam becomes a linearly polarized S wave. The linearly polarized S-wave first wavelength laser light transmitted through the first QWP 57 returns to the first dichroic mirror 48 through the optical path L1e.

  The linearly polarized S-wave first wavelength laser light reflected by the front side surface 48a of the first dichroic mirror 48 returns to the first CL 41 through the optical path L1d. When the first wavelength laser beam returns through the optical path L1d and passes through the first CL 41, the first wavelength laser beam of the linearly polarized S wave of the parallel light is the first wavelength laser beam of the linearly polarized S wave of the convergent light and Become. The linearly polarized S-wave first wavelength laser light transmitted through the first CL 41 returns to the PBS 40 through the optical path L1d.

  In the PBS 40, there is provided a special film 40c that reflects the linearly polarized S-wave first wavelength laser light substantially perpendicularly and transmits the linearly polarized P-wave first wavelength laser light substantially straight and transmits the optical path L1d. The linearly polarized S-wavelength first-wavelength laser light that has returned to the PBS 40 and is internally reflected substantially at a right angle by the PBS 40, reaches the PBS 25 through the optical path L2c.

  The linearly polarized S-wavelength first-wavelength laser light incident on the PBS 40 from the optical path L1d is reflected from the PBS 40 at a substantially right angle, then exits from the PBS 40, and enters the PBS 25 through the optical path L2c. The PBS 25 is configured to transmit a first wavelength laser beam having a wavelength of about 350 to 450 nm while traveling substantially straight in the PBS 25.

  The PBS 25 includes a special film 25c that forms a dichroic filter. A special film 25 c is provided in the PBS 25. More specifically, the film 25c is a special film 25c that transmits a first wavelength laser beam for "Blu-ray Disc" or a first wavelength laser beam for "HD DVD" having a wavelength of about 350 to 450 nm. ing. The film 25c is a special film 25c that transmits a third wavelength laser beam for DVD having a wavelength of about 630 to 685 nm. The film 25c is configured to reflect the second wavelength laser light for CD having a wavelength of about 765 to 830 nm. Since the special film 25c is provided in the PBS 25, the PBS 25 has a wavelength light for "Blu-ray Disc", a wavelength light for "HD DVD", a wavelength light for DVD, or a wavelength for CD. It exhibits different characteristics for light. The PBS 25 is also called, for example, a dichroic prism.

  The PBS 25 includes a substantially triangular prism-shaped first member 25a, a substantially triangular prism-shaped second member 25b fitted to the first member 25a, and a special film 25c between the first member 25a and the second member 25b. It is configured as a provision. By combining the substantially triangular prism-shaped first member 25a and the substantially triangular prism-shaped second member 25b, a column-shaped PBS 25 having a generally rhombic shape in plan view provided with a special film 25c is formed. A special film 25 c is provided between the first member 25 a constituting the PBS 25 and the second member 25 b constituting the PBS 25. The special film 25c transmits the “Blu-ray Disc” laser light or the “HD DVD” laser light having a wavelength of about 350 to 450 nm.

  The “Blu-ray Disc” laser light having a wavelength of about 350 to 450 nm incident on the PBS 25 by the PBS 25 having the special coating 25 c travels substantially straight and passes through the PBS 25 and is emitted from the PBS 25. Examples of the PBS 25 provided with a special film 25c therein include a PBS prism manufactured by Tamron Co., Ltd.

The linearly polarized S-wavelength first-wavelength laser light transmitted substantially straight through the PBS 25 reaches the sensor lens 80A through the optical path L2b.

  Astigmatism occurs in the first wavelength laser light when the linearly polarized S-wave first wavelength laser light passes through the sensor lens 80A. The sensor lens 80A is configured to generate astigmatism of the laser light. Aberration means that, for example, rays passing through a lens or the like are not correctly collected at one point, and an incomplete image is formed. Astigmatism means a difference in focus position. The sensor lens may be called, for example, a power lens, an anamorphic lens (anamorphic lens), or the like.

  The first wavelength laser light transmitted through the sensor lens 80A reaches the photodetector 90A through the optical path L2b. The photodetector 90A receives the laser light reflected from the optical disc 100 (FIGS. 2A, 3A), and 300 (FIG. 3B), converts the signal into an electrical signal, and converts the optical signal into an optical signal. (FIG. 2 (A), FIG. 3 (A)), and 300 (FIG. 3 (B)) are for detecting the information recorded. The photodetector 90A (FIG. 1) receives the laser light reflected from the optical disc 100 (FIGS. 2A, 3A), and 300 (FIG. 3B), and electrically converts the signal. Instead of the signal, a servo mechanism (not shown) of an OBL-equipped lens holder (not shown) constituting the OPU 1 (FIG. 1) is operated. The photodetector (photo detector / photo diode IC) is abbreviated as, for example, “PD” or “PDIC”.

  The diffused first wavelength laser light reflected by the signal unit 150 of the “Blu-ray Disc” standard optical disc 100 (FIGS. 2A and 3A) is transmitted by the signal unit 150 of the optical disc 100. When reflected, it turns from right-handed circularly polarized light to left-handed circularly polarized light, converted into parallel light by the first OBL 60 in the optical path L1f, and straight from left-handed circularly polarized light by the first QWP 57 (FIG. 1) in the optical path L1e. It becomes a polarized S wave, is changed from parallel light to convergent light by the first CL41 of the optical path L1d, is bent substantially at right angles by the first PBS 40 located at the branch point of the optical path L1c, the optical path L1d, the optical path L2c, and the optical path L2d, The light is applied to the PDIC 90A located at the end of the optical path L2b. The first-wavelength laser light reflected from the “Blu-ray Disc” standard optical disc 100 (FIG. 2A, FIG. 3A) follows the return path in this way, and enters the first PDIC 90A (FIG. 1). Irradiated.

  Next, an optical path until the laser light emitted from the first LD 10 (FIG. 1) is irradiated onto the “HD DVD” standard optical disc 300 (FIG. 3B) will be described. Current is supplied from the LDD 9 to the first LD 10, and information is recorded on the “HD DVD” standard optical disc 300 (FIG. 3B) by blue-violet laser light having a wavelength of 350 to 450 nm emitted from the first LD 10. Or information recorded on the optical disc 300 of the “HD DVD” standard is reproduced.

  Diffused light is emitted from the first LD 10 (FIG. 1). The first wavelength laser beam of the diffused light output from the first LD 10 passes through the optical path L1a and the first DOE 11 for “Blu-ray Disc” or “HD DVD”. When the laser beam having the first wavelength passes through the first DOE 11, the laser beam having the first wavelength becomes a linearly polarized P wave.

  The linearly polarized P-wave first wavelength laser light transmitted through the first DOE 11 passes through the optical path L1a and enters the PBS 35. In the PBS 35, a special film 35c is provided that allows the linearly polarized P wave to travel substantially straight and transmit, and reflects the linearly polarized S wave at a substantially right angle. Therefore, the laser beam of the linearly polarized P wave incident on the PBS 35 is Go straight through the PBS 35 and exit from the PBS 35. The linearly-polarized P-wavelength first-wavelength laser light transmitted through the first DOE 11 passes straight through the PBS 35 and is incident on the LCD 37 serving as the polarization direction conversion member 37.

The first-wavelength laser light transmitted substantially straight through the PBS 35 passes through the optical path L1c and the LCD 37. When data of the “HD DVD” standard optical disc 300 (FIG. 3B) is reproduced or when data is recorded on the “HD DVD” standard optical disc 300, electricity is applied to the LCD 37 (FIG. 1). The LCD 37 is energized. When the LCD 37 is in an energized state, the linearly polarized P-wave first wavelength laser light incident on the LCD 37 is changed from the polarization state and emitted from the LCD 37 as a linearly polarized S-wave first wavelength laser light. The first wavelength laser light transmitted through the LCD 37 and converted into the linearly polarized S wave reaches the PBS 40 through the optical path L1c.

  The PBS 40 is provided with a special coating 40c that reflects the linearly polarized S-wave first wavelength laser light substantially perpendicularly and transmits the linearly polarized P-wave first wavelength laser light substantially straight and transmits the PBS 40. The incident linearly polarized S-wave first wavelength laser light is reflected substantially at right angles in the PBS 40, passes through the PBS 40, and is emitted from the PBS 40. The linearly polarized S-wavelength first-wavelength laser light transmitted through the LCD 37 passes through the PBS 40 at a substantially right angle, and enters the liquid crystal correction element 52 through the optical path L2d.

  The S-wavelength first-wavelength laser light is reflected substantially perpendicularly by the PBS 40 and passes through the liquid crystal correction element 52. The liquid crystal correction element is capable of freely controlling liquid crystal molecules. By using the liquid crystal correction element, it is possible to suppress the occurrence of aberrations such as coma and spherical aberration in the optical disc when the laser beam is applied to the optical disc. The coma aberration is a phenomenon in which, for example, when light entering obliquely from an object point separated from the optical axes LA1 and LA2 is imaged through the lenses 60 and 70, the light spreads without forming a point and looks like a comet, for example. means.

  As described above, the OPU 1 is configured such that the first wavelength laser beam is applied to the optical disc 300 of the “HD DVD” standard (FIG. 3B) and focused on the signal portion 350 of the optical disc 300 of the “HD DVD” standard. A liquid crystal correction element 52 (FIG. 1) is configured to suppress the occurrence of aberrations such as coma and spherical aberration in the condensing spot S3 when S3 is formed by irradiation. Further, in this OPU 1, the third wavelength laser beam is applied to the “DVD” standard optical disc 300 (FIG. 3B), and the signal spot 350 of the “DVD” standard optical disc 300 is irradiated and formed. Then, the liquid crystal correction element 52 (FIG. 1) is configured to suppress the occurrence of aberrations such as coma and spherical aberration in the focused spot S3. The liquid crystal correction element 52 is, for example, a blue-violet laser beam (first wavelength laser beam) for “HD DVD” having a wavelength of about 350 to 450 nm, or a red laser beam (third) for “DVD” having a wavelength of about 630 to 685 nm. (Wavelength laser light) and the like.

  The liquid crystal correction element 52 also serves to correct, for example, either or both of vertical birefringence and in-plane birefringence of laser light applied to the optical disc 300 (FIG. 3B). . Examples of the birefringence include birefringence caused by thermal stress caused by “variation” of the temperature distribution of the disk molding die. In addition, when the resin material is poured into the cavity of the disk molding die and the disk 300 is molded, birefringence due to the flow residual stress of the resin material can be mentioned. These are called intrinsic birefringence. On the other hand, birefringence different from intrinsic birefringence includes stress birefringence generated in the disk 300 due to stress generated when the disk 300 rotates. Further, a change in the orientation refractive index generated in the disk 300 due to heat transmitted to the disk 300 or the like is also related to birefringence.

This OPU 1 (FIG. 1) is a laser beam having vertical birefringence or in-plane birefringence caused by the transparent resin substrates 310 and 320 constituting the “HD DVD” standard or “DVD” standard optical disc 300 (FIG. 3B). A liquid crystal correction element 52 that corrects one or both of the refractions is provided. This liquid crystal correction element 52 (FIG. 1) is made up of transparent resin substrates 310 and 320 constituting an optical disk 300 (FIG. 3B) of “HD DVD” standard or “DVD” standard.
Any one or both of the vertical birefringence and the in-plane birefringence of the laser beam caused by the above-described phenomenon is corrected together.

  If the OPU 1 includes the liquid crystal correction element 52 that corrects either or both of the vertical birefringence and the in-plane birefringence of the laser light applied to the optical disc 300, the signal surface 350 of the various optical discs 300 has a signal surface 350. Birefringence of the laser light that occurs when the laser light is irradiated can be suppressed. For example, in the OPU 1 that supports “Blu-ray Disc”, “HD DVD”, and the like, OBLs 60 and 70 having a large NA are used.

  For example, when the laser beam is converged by the OBL 70 having a large NA and the laser beam is irradiated onto the signal surface portion 350 of the “HD DVD” standard or “DVD” standard optical disc 300, the signal surface portion 350 of the optical disc 300 is irradiated and formed. The aberration of the spot S3 may become a special aberration due to birefringence by the transparent substrates 310 and 320 of the optical disc 300. The aberration of the spot S3 formed by irradiation on the signal surface portion 350 of the “HD DVD” standard or “DVD” standard optical disc 300 is caused by the birefringence of the transparent resin substrates 310 and 320 constituting the optical disc 300. The degree of aberration may be different between the vicinity of the center of the laser beam spot S3 formed on the surface and the vicinity of the peripheral edge of the laser beam spot S3.

  If the OPU 1 includes the liquid crystal correction element 52 that corrects either or both of vertical birefringence and in-plane birefringence caused by the transparent resin substrates 310 and 320 constituting the optical disc 300, the optical disc can be used. When data / information on the optical disc 300 is read by irradiating the signal surface portion 350 of the optical disc 300 with laser light, or when data / information is written or rewritten on the optical disc 300 by irradiating the signal surface portion 350 of the optical disc 300 with laser light, When the signal surface portion 350 of the optical disc 300 is irradiated with laser light to erase data / information on the optical disc 300, the transparent resin substrates 310, 320 of the optical disc 300 are caused by the transparent resin substrates 310, 320 constituting the optical disc 300. Due to the birefringence of the laser light generated in 320, the optical disc 300 It is likely to be avoided that adverse effect on the aberration correction of the signal face portion 350 laser light spot S3, irradiated formed is exerted.

  Corresponding to the amount of birefringence caused by the transparent resin substrates 310 and 320 constituting the optical disc 300 (FIG. 3B), the voltage applied to the liquid crystal correction element 52 (FIG. 1) is adjusted, and the optical disc 300 ( Either or both of the vertical birefringence and the in-plane birefringence of the laser light irradiated in FIG.

  By adjusting the voltage applied to the liquid crystal correction element 52, the aberration correction of the spot S3 formed by irradiating the signal surface portion 350 of the optical disc 300 with the laser light irradiated to the signal surface portion 350 of the optical disc 300 is performed satisfactorily. Further, the voltage applied to the liquid crystal correction element 52 is adjusted in accordance with the amount of birefringence of the laser light caused by the transparent resin substrates 310 and 320 constituting the optical disc 300, so that the transparent resin constituting the optical disc 300 is adjusted. Correction of one or both of the vertical birefringence and the in-plane birefringence of the laser light caused by the substrates 310 and 320 is performed together.

  As described above, the aberration / birefringence correction method of the OPU 1 performs the spherical aberration correction of the laser beam spot S3 by using the liquid crystal correction element 52, and at the same time, adjusts the applied voltage of the liquid crystal correction element 52 to reduce the optical disc. The OPU1 aberration / birefringence correction method corrects the internal birefringence and vertical birefringence of 300.

In contrast to the OPU aberration / birefringence correction method in which only the spherical aberration correction of the laser beam spot (S3) is performed using the liquid crystal correction element (52), the OPU1 aberration / birefringence correction method has the above liquid crystal correction. The element 52 is used to adjust the voltage applied to the liquid crystal correction element 52 to correct the spherical aberration of the spot S3 of the laser beam, and either vertical birefringence or in-plane birefringence of the laser beam irradiated to the optical disc 300. Either or both corrections are performed together. The parentheses () attached to the reference numerals in this specification are used for the sake of convenience in order to explain what is slightly different from the illustrated one.

  In contrast to the spot correction method in which only the spherical aberration of the laser beam spot (S3) is corrected using the liquid crystal correction element (52), the OPU1 aberration / birefringence correction method is performed, thereby performing light spot correction. The corrected spot correction waveform / shape and the maximum / minimum value of the wavefront after the spherical aberration correction of the light spot S3 is changed. By performing the aberration / birefringence correction method of the OPU 1 in contrast to the spot correction method in which only the spherical aberration of the laser beam spot (S3) is simply corrected using the liquid crystal correction element (52), the laser beam spot S3 is corrected. Waveform and shape correction effects are different. When the influence of birefringence is estimated by numerical calculation, for example, the Jones matrix is used. The Jones matrix is a matrix with 2 rows and 2 columns that represents characteristics of a polarizer, a phase plate, and the like.

  The S-wavelength first wavelength laser light transmitted through the liquid crystal correction element 52 (FIG. 1) passes through the second CL 61 through the optical path L2d. The S-wavelength first-wavelength laser light transmitted through the second CL 61 passes through the optical path L2d as substantially parallel light and reaches the polarizing mirror 63, so-called dichroic mirror 63.

  The first wavelength laser beam of linearly polarized S wave irradiated to the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is substantially transmitted through the front side surface 63a of the substantially dichroic second dichroic mirror 63 and second. Enters the dichroic mirror 63. For example, approximately 92 to 98% of the linearly polarized S-wave first wavelength laser light that has entered the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is approximately triangular. The light is reflected at a substantially right angle by the back side surface 63 b of the columnar second dichroic mirror 63 and travels along the optical path L <b> 2 e toward the second quarter-wave plate (QWP) 67. Further, for example, approximately 2 to 8% of the first-wavelength laser light of the linearly polarized S wave incident on the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is The light is emitted from the back side surface 63b of the substantially triangular prism-shaped second dichroic mirror 63 by being bent at an obtuse angle and travels toward the second light receiving element (FMD) 65 along the optical path L2g.

  More specifically, approximately 93 to 97% of the first-wavelength laser light of the linearly polarized S wave incident on the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d. Are reflected at substantially right angles on the back side surface 63 b of the substantially triangular prism-shaped second dichroic mirror 63 and travel on the optical path L <b> 2 e toward the second QWP 67. In addition, approximately 3 to 7% of linearly polarized S-wave first-wavelength laser light that has entered the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is approximately triangular. It is bent and emitted from the back side surface 63b of the columnar second dichroic mirror 63 so as to form an obtuse angle, and travels along the optical path L2g toward the second FMD 65.

  The dichroic mirror 63 includes a special film 63c that forms a dichroic filter. A dichroic film 63 c is formed on the back side surface 63 b of the second dichroic mirror 63.

Reflection of linearly polarized S-wave first wavelength laser light on the second dichroic mirror 63 when linearly polarized S-wave first wavelength laser light is applied to the special film 63c on the back side surface 63b of the second dichroic mirror 63. When the amount is smaller than 92%, for example, when the transmission amount of the first wavelength laser light of the linearly polarized S wave in the second dichroic mirror 63 is larger than 8%, for example, the optical disc 300 (FIG. 3B). Insufficient light quantity to irradiate the first wavelength laser beam.

  More specifically, the linearly polarized light in the second dichroic mirror 63 when the first wavelength laser beam of the linearly polarized S wave is applied to the special film 63c on the back side surface 63b of the second dichroic mirror 63 (FIG. 1). When the reflection amount of the S-wavelength first-wavelength laser light is less than 93%, that is, when the transmission amount of the linearly polarized S-wavelength first-wavelength laser light through the second dichroic mirror 63 is more than 7%, the optical disk The amount of light necessary for irradiating 300 (FIG. 3B) with the first wavelength laser light is insufficient.

  The first wavelength of the linearly polarized S wave in the second dichroic mirror 63 when the first wavelength laser beam of the linearly polarized S wave is applied to the special film 63c on the back surface 63b of the second dichroic mirror 63 (FIG. 1). When the reflection amount of the laser light is larger than 98%, for example, when the transmission amount of the first wavelength laser light of the linearly polarized S wave in the second dichroic mirror 63 is smaller than 2%, for example, the second FMD 65 The required amount of received first wavelength laser light is insufficient.

  More specifically, when the first wavelength laser beam of the linearly polarized S wave is applied to the special film 63c on the back side surface 63b of the second dichroic mirror 63, the first of the linearly polarized S wave in the second dichroic mirror 63 is applied. When the reflection amount of the one-wavelength laser light is larger than 97%, that is, when the transmission amount of the first-wavelength laser light of the linearly polarized S wave in the second dichroic mirror 63 is smaller than 3%, the second FMD 65 The required amount of received first wavelength laser light is insufficient.

  Reflection of linearly polarized S-wave first wavelength laser light on the second dichroic mirror 63 when linearly polarized S-wave first wavelength laser light is applied to the special film 63c on the back side surface 63b of the second dichroic mirror 63. When the amount is, for example, 95%, that is, when the transmission amount of the first-wavelength laser light of the linearly polarized S wave in the second dichroic mirror 63 is, for example, 5%, the optical disc 300 (FIG. 3B) A sufficient amount of laser light is irradiated and an appropriate amount of laser light required for the second FMD 65 (FIG. 1) is irradiated. Therefore, it is preferable that the OPU 1 is equipped with the second dichroic mirror 63 having such characteristics.

  The dichroic film 63c of the dichroic mirror 63 reflects most of the “HD DVD” laser light (first wavelength laser light) of linearly polarized S wave having a wavelength of about 350 to 450 nm. When the first wavelength laser beam having a wavelength of 350 to 450 nm of the linearly polarized S wave is applied to the second dichroic mirror 63, the second dichroic mirror 63 has the first wavelength laser beam having a wavelength of most 350 to 450 nm. The first wavelength laser beam having a wavelength of 350 to 450 nm is transmitted. Examples of the dichroic mirror 63 having a special film 63c on the surface 63b include Tamron Co., Ltd .: dichroic mirror, dichroic prism, and the like.

  The obtuse angle from the back side surface 63b of the substantially triangular prism-shaped second dichroic mirror 63 is incident on the second dichroic mirror 63 through the front side surface 63a of the substantially triangular prism-shaped second dichroic mirror 63, and passes through the second dichroic mirror 63. A part of the first wavelength laser beam bent and emitted so as to reach the second FMD 65 through the optical path L2g. The second FMD 65 is configured as a front monitor diode that is irradiated with part of the laser light. The FMD 65 monitors the laser light output from the LD 10, 20, 30 and applies feedback for controlling the LD 10, 20, 30.

Most of the first wavelength laser light reflected from the back side surface 63b of the substantially triangular prism-shaped second dichroic mirror 63 at a substantially right angle reaches the second QWP 67 through the optical path L2e. The first wavelength laser beam reflected by the back side surface 63 b of the substantially triangular prismatic dichroic mirror 63 enters the second QWP 67 adjacent to the dichroic mirror 63. The linearly polarized S-wave first wavelength laser light transmitted through the second QWP 67 becomes circularly polarized light. In the second QWP 67, the linearly polarized S-wave first wavelength laser light becomes, for example, left-handed circularly polarized light.

  The optical path L2e from the second dichroic mirror 63 through the second OBL 70 without the second QWP 67 being positioned in the optical paths L1a, L1c, L2d from the first LD 10 to the second dichroic mirror 63 or When the second QWP 67 (FIG. 1) is positioned in any one of the optical paths L2e and L2fd of L2fd (FIG. 3B), for example, a part of the first wavelength via the second dichroic mirror 63 It is easy to avoid that the laser beam adversely affects the second FMD 65.

  The first-wavelength laser light that has passed through the second QWP 67 and turned into left-handed circularly polarized light passes through the optical path L2e, and is the second reflectivity located above the housing base wall reference portion 7h (FIG. 3B). Applied to a mirror (MR) 68. The second reflective MR 68 is provided with a coating 68a that substantially totally reflects the laser light. Therefore, the laser beam applied to the reflective MR 68 is substantially totally reflected.

  The first-wavelength laser light that has passed through the second QWP 67 (FIG. 1) and turned into circularly polarized light turning counterclockwise passes through the optical path L2e and reflects the reflective MR 68 (FIG. 3B) at a slightly acute angle from a right angle. Then, the light passes through the aperture limiting element 69 through the optical path L2fd. On the first side surface 69a of the aperture limiting element 69, a part of the infrared laser beam for CD (second wavelength laser beam) having a wavelength of about 765 to 830 nm is masked and blocked, and “HD DVD having a wavelength of about 350 to 450 nm is blocked. A special film 69c that transmits the blue-violet laser beam (first wavelength laser beam) for "and the red laser beam for DVD (third wavelength laser beam) having a wavelength of about 630 to 685 nm without masking. ing. Since such a special film 69c is provided on the first side surface 69a of the aperture limiting element 69, the aperture limiting element 69 is an infrared laser beam for CD having a wavelength of about 765 to 830 nm (second wavelength laser beam). The blue-violet laser beam (first wavelength laser beam) for "HD DVD" having a wavelength of about 350 to 450 nm and the red laser beam (third wavelength laser beam) for DVD having a wavelength of about 630 to 685 nm. Does not work. Therefore, even if the left-handed circularly polarized first wavelength laser light having a wavelength of about 350 to 450 nm and having a blue violet color passes through the aperture limiting element 69, no significant change occurs in the left-handed circularly polarized first wavelength laser light. The left-turn circularly polarized first wavelength laser light is incident on the aperture limiting element 69 from the first side surface 69a of the aperture limiting element 69 without being masked, and is emitted from the second side surface 69b of the aperture limiting element 69. The As described above, the OPU 1 includes the aperture limiting element 69 that acts on the second wavelength laser light without acting on the first wavelength laser light and / or the third wavelength laser light.

The special films 25c, 35c, 40c, 48c, 63c, and 69c such as the dichroic films 48c and 63c and the polarizing film 40c are formed on a desired surface based on, for example, a vacuum deposition method or a sputtering method. . The special films 25c, 35c, 40c, 48c, 63c, and 69c such as the dichroic films 48c and 63c and the polarizing film 40c are, for example, SiO ₂ , ZnO ₂ , Ta ₂ O ₅ , TiO ₂ and Ti _2. The layer contains at least one substance selected from the group consisting of O ₅ . Specifically, each of the dichroic films 48c and 63c and the polarizing film 40c is at least one selected from the group consisting of SiO ₂ , ZnO ₂ , Ta ₂ O ₅ , TiO ₂ and Ti ₂ O ₅ . Configured as a thin layer containing the substance.

The left-turn circularly polarized first wavelength laser light transmitted through the aperture limiting element 69 passes through the second objective lens 70. The left-turn circularly polarized first wavelength laser light that is substantially parallel light becomes convergent light by the second OBL 70 having a numerical aperture of about 0.6 to 0.65, and is a signal portion 350 of the optical disc 300 of the “HD DVD” standard. Is irradiated.

  When the focus servo of the second OBL 70 mounted on the lens holder (not shown) is performed on the optical disc 300, the lens holder including the second OBL 70 is moved along the focus direction Df. In addition, when the tracking servo of the second OBL 70 mounted on the lens holder (not shown) is performed on the optical disc 300, the lens holder including the second OBL 70 is moved along the tracking direction Dr. Further, when tilt control of the second OBL 70 mounted on the lens holder is performed with respect to the optical disc 300, the lens holder including the second OBL 70 is swung along the tilt direction Dt. The lens holder equipped with the second OBL 70 is driven using a plurality of wires (not shown). In addition, a first OBL 60 is mounted on a lens holder (not shown) adjacent to the second OBL 70 (FIG. 1).

  The first wavelength laser beam of the diffused light emitted from the first LD 10 is converted into a linearly polarized P wave by the first DOE 11 in the optical path L1a, converted into a linearly polarized S wave by the LCD 37 in the energized state of the optical path L1c, and the optical path L1c. The first PBS 40 located at the branch point of the optical path L1d, the optical path L2c, and the optical path L2d is bent at a substantially right angle, changed from diffused light to substantially parallel light by the second CL 61 of the optical path L2d, and straight by the second QWP 67 of the optical path L2e. From the polarized S wave, it becomes a left-turn circularly polarized light, becomes convergent light by the second OBL 70 in the optical path L2fd (FIG. 3B), and is condensed on the signal part 350 of the optical disk 300 of “HD DVD” standard. The laser beam of the first wavelength follows the forward path in this way and is condensed on the “HD DVD” standard optical disc 300 as the third medium 300.

  Next, the return path of the first wavelength laser beam reflected to the “HD DVD” standard optical disc 300 will be described. When the first wavelength laser light is reflected by the signal unit 350 of the “HD DVD” standard optical disc 300, the left-turn circularly polarized first wavelength laser light becomes right-turn circularly polarized light. The right-turn circularly polarized first wavelength laser light turns into diffused light, returns through the optical path L2fd, and reaches the second OBL 70. The right-turn circularly polarized first wavelength laser light that is diffused light becomes substantially parallel light by the second OBL 70. The right-turn circularly polarized first wavelength laser light that passes through the second OBL 70 and returns to the optical path L2fd passes through the aperture limiting element 69 and reaches the second reflective MR 68.

  The right-turn circularly polarized first wavelength laser beam reflected by the second reflective MR 68 returns to the second QWP 67 through the optical path L2e (FIG. 1). When the first wavelength laser light returns through the optical path L2e and passes through the second QWP 67, the circularly polarized first wavelength laser light turning clockwise becomes a linearly polarized P wave. The linearly polarized P-wave first wavelength laser light transmitted through the second QWP 67 enters the second dichroic mirror 63 adjacent to the second QWP 67.

  The linearly polarized P-wave first wavelength laser beam internally reflected by the back side surface 63b of the second dichroic mirror 63 returns to the second CL 61 through the optical path L2d. When the first wavelength laser beam returns through the optical path L2d and passes through the second CL 61, the first wavelength laser beam of the substantially parallel linearly polarized P wave is the first wavelength laser beam of the linearly polarized P wave of the convergent light. It becomes. The linearly polarized P-wavelength first wavelength laser light transmitted through the second CL 61 returns to the liquid crystal correction element 52 through the optical path L2d. The linearly polarized P-wavelength first wavelength laser light transmitted through the liquid crystal correction element 52 returns to the PBS 40 through the optical path L2d.

  In the PBS 40, there is provided a special film 40c that allows the linearly polarized P-wave first wavelength laser light to travel substantially straight and transmits it, and reflects the linearly polarized S-wave first wavelength laser light at a substantially right angle. The linearly polarized P-wavelength first-wavelength laser light that has returned to the PBS 40 passes substantially straight through the PBS 40 and reaches the PBS 25 through the optical path L2c.

  The linearly polarized P-wavelength first-wavelength laser light that has entered the PBS 40 from the optical path L2d is transmitted through the PBS 40 in a straight line and then emitted from the PBS 40, and then enters the PBS 25 through the optical path L2c.

  The laser beam for “HD DVD” having a wavelength of about 350 to 450 nm incident on the PBS 25 by the PBS 25 provided with the special film 25 c travels substantially straight and passes through the PBS 25 and is emitted from the PBS 25. The linearly polarized P-wavelength first-wavelength laser light transmitted substantially straight through the PBS 25 reaches the sensor lens 80A through the optical path L2b. Astigmatism occurs in the first wavelength laser light when the linearly polarized P-wave first wavelength laser light passes through the sensor lens 80A. The first wavelength laser light transmitted through the sensor lens 80A reaches the PDIC 90A through the optical path L2b.

  The first wavelength laser light of the diffused light reflected by the signal unit 350 of the “HD DVD” standard optical disc 300 (FIG. 3B) rotates left when reflected by the signal unit 350 of the optical disc 300. From the circularly polarized light, it becomes right-turned circularly polarized light, becomes substantially parallel light by the second OBL 70 in the optical path L2fd, and by the second QWP 67 (FIG. 1) in the optical path L2e, it turns from right-handed circularly polarized light to the linearly polarized P-wave, The light is changed from substantially parallel light to convergent light by the second CL 61 of L2d, and irradiated to the PDIC 90A located at the end of the optical path L2b. The first-wavelength laser light reflected from the “HD DVD” standard optical disc 300 (FIG. 3B) follows the return path in this way, and is irradiated to the first PDIC 90A (FIG. 1).

  Next, the optical path until the laser beam emitted from the third LD 30 (FIG. 1) is irradiated onto the DVD standard optical disc 300 (FIG. 3B) will be described. Since the DVD standard optical disc 300 and the “HD DVD” standard optical disc 300 are compatible, the optical path of the laser beam for CD emitted from the second LD 20 (FIG. 1) for convenience. Prior to the description, the optical path of the DVD laser light emitted from the third LD 30 will be described.

  Current is supplied from the LDD 9 to the third LD 30, and information is recorded on the DVD standard optical disc 300 (FIG. 3B) by the red laser light having a wavelength of 630 to 685 nm emitted from the third LD 30. The information recorded on the DVD standard optical disc 300 is reproduced. The third LD 30 is a DVD laser diode capable of emitting red laser light having a wavelength of about 630 to 685 nm and a reference wavelength of about 635 nm or about 650 nm, for example.

  Diffused light is emitted from the third LD 30 (FIG. 1). The third wavelength laser beam of the diffused light output from the third LD 30 passes through the optical path L1b and the third DOE 31 for DVD. When the third wavelength laser beam passes through the third DOE 31, the third wavelength laser beam becomes a linearly polarized S wave.

  The linearly polarized S-wavelength third-wavelength laser light transmitted through the third DOE 31 is incident on the PBS 35 through the optical path L1b. In the PBS 35, a special film 35 c that reflects the linearly polarized S wave at a substantially right angle and transmits the linearly polarized P wave substantially straightly is transmitted, so that the laser beam of the linearly polarized S wave incident on the PBS 35 is The light is internally reflected at a substantially right angle, passes through the PBS 35, and exits from the PBS 35. The linearly polarized S-wavelength third-wavelength laser light transmitted through the third DOE 31 passes through the PBS 35 by being internally reflected substantially at a right angle, and is incident on the LCD 37 serving as a polarization direction changing member 37.

The third-wavelength laser light internally reflected and transmitted through the PBS 35 passes through the optical path L1c and the LCD 37. When data of the DVD standard optical disc 300 (FIG. 3B) is reproduced or when data is recorded on the DVD standard optical disc 300, the LC
Electricity does not flow through D37 (FIG. 1), and the LCD 37 is not energized. When the LCD 37 is not energized, the linearly polarized S-wave third wavelength laser light incident on the LCD 37 is emitted from the LCD 37 as a linearly polarized S-wave third wavelength laser light without changing the polarization state. The The linearly polarized S-wavelength third-wavelength laser light transmitted through the LCD 37 reaches the PBS 40 through the optical path L1c.

  The PBS 40 is provided with a special coating 40c that reflects the linearly polarized S wave of the third wavelength laser light substantially at right angles and transmits the linearly polarized P wave of the third wavelength laser light in a substantially straight line. The incident linearly polarized S-wavelength third-wavelength laser light is reflected substantially at right angles in the PBS 40, passes through the PBS 40, and is emitted from the PBS 40. The linearly polarized S-wavelength third-wavelength laser light transmitted through the LCD 37 passes through the PBS 40 at a substantially right angle and enters the liquid crystal correction element 52 through the optical path L2d.

  The S-wavelength third-wavelength laser light is reflected at a substantially right angle by the PBS 40 and passes through the liquid crystal correction element 52. The S-wavelength third-wavelength laser light transmitted through the liquid crystal correction element 52 passes through the second CL 61 through the optical path L2d. The S-wavelength third-wavelength laser light transmitted through the second CL 61 passes through the optical path L2d as substantially parallel light and reaches the dichroic mirror 63.

  The linearly polarized S-wave third-wavelength laser beam irradiated on the front side surface 63a of the second dichroic mirror 63 through the optical path L2d substantially passes through the front side surface 63a of the second triangular dichroic mirror 63 and is second transmitted. Enters the dichroic mirror 63. For example, approximately 92 to 98% of the linearly polarized S-wave third-wavelength laser light that has entered the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is approximately triangular. The light is reflected at a substantially right angle by the back side surface 63 b of the columnar second dichroic mirror 63 and travels along the optical path L <b> 2 e toward the second QWP 67. Further, for example, approximately 2 to 8% of the third-wavelength laser light of the linearly polarized S wave incident on the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is The light is emitted from the rear side surface 63b of the substantially triangular prism-shaped second dichroic mirror 63 by being bent at an obtuse angle and travels toward the second FMD 65 along the optical path L2g.

  More specifically, approximately 93 to 97% of linearly polarized S-wave third-wavelength laser light that has entered the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d. Are reflected at substantially right angles on the back side surface 63 b of the substantially triangular prism-shaped second dichroic mirror 63 and travel on the optical path L <b> 2 e toward the second QWP 67. Further, approximately 3 to 7% of the linearly polarized S-wave third-wavelength laser light that has entered the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is approximately triangular. It is bent and emitted from the back side surface 63b of the columnar second dichroic mirror 63 so as to form an obtuse angle, and travels along the optical path L2g toward the second FMD 65.

  Reflection of linearly polarized S-wave third-wavelength laser light on the second dichroic mirror 63 when the third-wavelength laser light of linearly-polarized S-wave is applied to the special film 63c on the back side surface 63b of the second dichroic mirror 63. For example, when the amount is smaller than 92%, specifically 93%, that is, the amount of transmission of the third wavelength laser light of the linearly polarized S wave in the second dichroic mirror 63 is, for example, 8%, specifically 7%. In many cases, the amount of light necessary for irradiating the optical disc 300 (FIG. 3B) with the third wavelength laser light is insufficient.

The third wavelength of the linearly polarized S wave in the second dichroic mirror 63 when the third wavelength laser beam of the linearly polarized S wave is applied to the special film 63c on the back surface 63b of the second dichroic mirror 63 (FIG. 1). When the amount of reflection of laser light is larger than 98%, specifically 97%, for example, the transmission amount of the third wavelength laser light of the linearly polarized S wave in the second dichroic mirror 63 is specifically 2%. If it is less than 3%, the amount of received third-wavelength laser light required for the second FMD 65 is insufficient.

  Reflection of linearly polarized S-wave third-wavelength laser light on the second dichroic mirror 63 when the third-wavelength laser light of linearly-polarized S-wave is applied to the special film 63c on the back side surface 63b of the second dichroic mirror 63. When the amount is, for example, 95%, that is, when the transmission amount of the third-wavelength laser light of the linearly polarized S wave in the second dichroic mirror 63 is, for example, 5%, the optical disc 300 (FIG. 3B) A sufficient amount of laser light is irradiated and an appropriate amount of laser light required for the second FMD 65 (FIG. 1) is irradiated. Therefore, it is preferable that the OPU 1 is equipped with the second dichroic mirror 63 having such characteristics.

  The dichroic film 63c of the dichroic mirror 63 reflects most of the linearly polarized S-wave DVD laser light (third wavelength laser light) having a wavelength of about 630 to 685 nm. When the third wavelength laser beam having a wavelength of 630 to 685 nm of the linearly polarized S wave is applied to the second dichroic mirror 63, the second dichroic mirror 63 causes the third wavelength laser beam having most of the wavelengths of 630 to 685 nm. Is reflected, and a part of the third wavelength laser beam having a wavelength of 630 to 685 nm is transmitted.

  The obtuse angle from the back side surface 63b of the substantially triangular prism-shaped second dichroic mirror 63 is incident on the second dichroic mirror 63 through the front side surface 63a of the substantially triangular prism-shaped second dichroic mirror 63, and passes through the second dichroic mirror 63. A part of the third-wavelength laser light that is bent so as to be emitted passes through the optical path L2g and reaches the second FMD 65.

  Most of the third-wavelength laser light reflected from the back side surface 63b of the substantially triangular prism-shaped second dichroic mirror 63 at a substantially right angle reaches the second QWP 67 through the optical path L2e. The third wavelength laser light reflected by the back side surface 63 b of the substantially triangular prismatic dichroic mirror 63 enters the second QWP 67 adjacent to the dichroic mirror 63. The linearly polarized S-wave third-wavelength laser light transmitted through the second QWP 67 becomes circularly polarized light. The third-wavelength laser light of linearly polarized S wave becomes, for example, left-handed circularly polarized light in the second QWP 67.

  The optical path L2e from the second dichroic mirror 63 through the second OBL 70 without the second QWP 67 being positioned in the optical paths L1b, L1c, L2d from the third LD 30 to the second dichroic mirror 63 or When the second QWP 67 (FIG. 1) is positioned in any one of the optical paths L2e and L2fd in L2fd (FIG. 3B), for example, a part of the third wavelength via the second dichroic mirror 63 It is easy to avoid that the laser beam adversely affects the second FMD 65.

  The third-wavelength laser light that has passed through the second QWP 67 and turned into left-handed circularly polarized light passes through the optical path L2e, and is the second reflectivity located on the upper side of the housing base wall reference portion 7h (FIG. 3B). Applied to MR68. Since the second reflective MR 68 is provided with the coating 68a that substantially totally reflects the laser light, the laser light applied to the reflective MR 68 is substantially totally reflected.

The third-wavelength laser light that has passed through the second QWP 67 (FIG. 1) and turned to circularly polarized left-handed light passes through the optical path L2e and reflects the reflective MR 68 (FIG. 3B) at a slightly sharper angle than the right angle. Then, the light passes through the aperture limiting element 69 through the optical path L2fd. On the first side surface 69a of the aperture limiting element 69, a part of the infrared laser beam for CD (second wavelength laser beam) having a wavelength of about 765 to 830 nm is masked to be blocked. A special film 69c that transmits the blue-violet laser beam (first wavelength laser beam) for "and the red laser beam for DVD (third wavelength laser beam) having a wavelength of about 630 to 685 nm without masking. ing. Since such a special film 69c is provided on the first side surface 69a of the aperture limiting element 69, the aperture limiting element 69 converts the red laser beam for DVD (third wavelength laser beam) having a wavelength of about 630 to 685 nm. Does not work. Accordingly, even if the left-handed circularly polarized third-wavelength laser light having a red wavelength of about 630 to 685 nm passes through the aperture limiting element 69, no significant change occurs in the left-handed circularly-polarized third wavelength laser light. The left-turn circularly polarized third-wavelength laser light enters the aperture limiting element 69 from the first side surface 69a of the aperture limiting element 69 without being masked, and exits from the second side surface 69b of the aperture limiting element 69. The

  The left-turn circularly polarized third-wavelength laser light transmitted through the aperture limiting element 69 passes through the second OBL 70. The left-turn circularly polarized third-wavelength laser light that is substantially parallel light becomes convergent light by the second OBL 70 having a numerical aperture of approximately 0.6 to 0.65, and is applied to the signal portion 350 of the DVD standard optical disk 300. The

  When the focus servo of the second OBL 70 mounted on the lens holder (not shown) is performed on the optical disc 300, the lens holder including the second OBL 70 is moved along the focus direction Df. In addition, when the tracking servo of the second OBL 70 mounted on the lens holder (not shown) is performed on the optical disc 300, the lens holder including the second OBL 70 is moved along the tracking direction Dr. Further, when tilt control of the second OBL 70 mounted on the lens holder is performed with respect to the optical disc 300, the lens holder including the second OBL 70 is swung along the tilt direction Dt.

  The diffused third-wavelength laser light emitted from the third LD 30 (FIG. 1) is converted into linearly polarized S waves by the third DOE 31 in the optical path L1b, and is branched into the optical path L1c, the optical path L1d, the optical path L2c, and the optical path L2d. The first PBS 40 located at the point is bent at a substantially right angle, changed from the diffused light to the substantially parallel light by the second CL 61 of the optical path L2d, and becomes the left-turned circularly polarized light from the linearly polarized S wave by the second QWP 67 of the optical path L2e, The second OBL 70 in the optical path L2fd (FIG. 3B) becomes converged light and is condensed on the signal portion 350 of the DVD standard optical disc 300. The laser beam of the third wavelength follows the forward path in this way, and is focused on the DVD standard optical disc 300 as the third medium 300.

  Next, the return path of the third wavelength laser beam reflected from the DVD standard optical disc 300 will be described. When the third wavelength laser light is reflected by the signal unit 350 of the DVD standard optical disk 300, the left-handed circularly polarized third-wavelength laser light becomes right-handed circularly polarized light. The right-turn circularly polarized third-wavelength laser light becomes diffused light, returns through the optical path L2fd, and reaches the second OBL 70. The right-turn circularly polarized third-wavelength laser light that is diffused light becomes substantially parallel light by the second OBL 70. The right-turn circularly polarized third-wavelength laser light that passes through the second OBL 70 and returns to the optical path L2fd passes through the aperture limiting element 69 and reaches the second reflective MR 68.

  The right-turn circularly polarized third-wavelength laser light reflected by the second reflective MR 68 returns to the second QWP 67 through the optical path L2e (FIG. 1). When the third wavelength laser beam returns through the optical path L2e and passes through the second QWP 67, the circularly polarized third wavelength laser beam that turns clockwise becomes a linearly polarized P wave. The linearly polarized P-wavelength third-wavelength laser light transmitted through the second QWP 67 enters the second dichroic mirror 63 adjacent to the second QWP 67.

The linearly polarized P-wavelength third-wavelength laser beam internally reflected by the back side surface 63b of the second dichroic mirror 63 returns to the second CL 61 through the optical path L2d. When the third wavelength laser beam returns through the optical path L2d and passes through the second CL 61, the third wavelength laser beam of the substantially parallel linearly polarized P wave is the third wavelength laser beam of the linearly polarized P wave of the convergent light. It becomes. The linearly polarized P-wavelength third-wavelength laser light transmitted through the second CL 61 returns to the liquid crystal correction element 52 through the optical path L2d. The third-wavelength laser beam of linearly polarized P wave that has passed through the liquid crystal correction element 52 returns to the optical path L2d and returns to PB
S40 is reached.

  In the PBS 40, there is provided a special film 40c that allows the linearly polarized P-wave third-wavelength laser light to pass substantially straight through and reflects the linearly-polarized S-wave third-wavelength laser light at a substantially right angle, so that the optical path L2d The linearly polarized P-wavelength third-wavelength laser light returning to PBS 40 passes through the PBS 40 substantially straight, passes through the optical path L2c, and reaches the PBS 25.

  The linearly polarized P-wavelength third-wavelength laser light incident on the PBS 40 from the optical path L2d is emitted from the PBS 40 after passing through the PBS 40 substantially straight, and then enters the PBS 25 through the optical path L2c. The PBS 25 is configured to transmit a third wavelength laser beam having a wavelength of about 630 to 685 nm while traveling substantially straight in the PBS 25.

  The DVD laser light having a wavelength of about 630 to 685 nm incident on the PBS 25 is substantially straight and passes through the PBS 25 and is emitted from the PBS 25 by the PBS 25 having the special film 25c. The linearly polarized P-wavelength third-wavelength laser light transmitted substantially straight through the PBS 25 reaches the sensor lens 80A through the optical path L2b. Astigmatism occurs in the third wavelength laser light when the third wavelength laser light of linearly polarized P wave passes through the sensor lens 80A. The third wavelength laser light transmitted through the sensor lens 80A reaches the PDIC 90A through the optical path L2b.

  The diffused third wavelength laser light reflected by the signal part 350 of the DVD standard optical disk 300 (FIG. 3B) is reflected from the left-handed circularly polarized light when reflected by the signal part 350 of the optical disk 300. Right-handed circularly polarized light becomes substantially parallel light by the second OBL 70 in the optical path L2fd, and right-handed circularly polarized light becomes linearly polarized P-wave by the second QWP 67 (FIG. 1) in the optical path L2e. The second CL 61 changes the light from substantially parallel light to converged light, and irradiates the PDIC 90A located at the end of the optical path L2b. The third-wavelength laser light reflected from the DVD-standard optical disk 300 (FIG. 3B) follows the return path in this manner and is applied to the first PDIC 90A (FIG. 1).

  Next, the optical path until the laser beam emitted from the second LD 20 (FIG. 1) is irradiated onto the CD standard optical disc 200 (FIG. 2B) will be described. Current is supplied from the LDD 9 to the second LD 20, and information is recorded on the CD standard optical disc 200 (FIG. 2B) by infrared laser light having a wavelength of 765 to 830 nm emitted from the second LD 20. Or information recorded on the CD standard optical disc 200 is reproduced. The second LD 20 is a CD laser diode capable of emitting infrared laser light having a wavelength of about 765 to 830 nm and a reference wavelength of about 780 nm, for example. The second LD 20 includes a light emitting unit 20a that emits infrared laser light having a wavelength of approximately 765 to 830 nm, a light detecting unit 20b that detects infrared laser light having a wavelength of approximately 765 to 830 nm, and the light emitting unit 20a and light. It is a special semiconductor laser diode provided with a metal cover 20c that protects the detector 20b from the outside.

  Diffused light is emitted from the second LD 20 (FIG. 1). The second wavelength laser light of the diffused light output from the second LD 20 passes through the optical path L2a and passes through the second DOE 21 for CD. The second DOE 21 includes a hologram (not shown), and is configured as a special hologram element, for example. The hologram means, for example, a holography that is applied and a laser beam or the like is used and various kinds of materials are printed on a special film or plastic plate. A special LD 20 and a special DOE 21 are combined to form a hologram laser diode unit 22. When the laser beam of the second wavelength passes through the second DOE 21, the laser beam of the second wavelength becomes a linearly polarized S wave.

The second-wavelength laser light that has passed through the second DOE 21 and has become a linearly polarized S wave passes through the divergent lens 23. The divergent lens 23 collects laser light emitted from the LD. The divergent lens 23 is sometimes called, for example, a coupling lens or an intermediate lens.

  The linearly polarized S-wavelength second-wavelength laser light transmitted through the divergent lens 23 enters the PBS 25 through the optical path L2a. Since the special film 25c for reflecting the second wavelength light is provided in the PBS 25, the linearly polarized S-wave laser light incident on the PBS 25 is internally reflected so as to have an obtuse angle, and the PBS 25 Passes through and exits from the PBS 25. The linearly polarized S-wavelength second-wavelength laser light transmitted through the second DOE 21 is internally reflected through the PBS 25 so as to form an obtuse angle, passes through the optical path L2c, and reaches the PBS 40.

  Since the special film 40c that allows the second wavelength laser light to pass substantially straightly through the PBS 40 is provided, the linearly polarized S-wave second wavelength laser light incident on the PBS 40 passes through the PBS 40 and is emitted from the PBS 40. To do. The linearly polarized S-wave second-wavelength laser light emitted from the PBS 25 passes through the optical path L2c, travels substantially straight through the PBS 40, and enters the liquid crystal correction element 52 through the optical path L2d.

  The S-wavelength second-wavelength laser light travels substantially straight through the PBS 40 and passes through the liquid crystal correction element 52. The S-wavelength second-wavelength laser light transmitted through the liquid crystal correction element 52 passes through the second CL 61 through the optical path L2d. The S-wavelength second-wavelength laser light transmitted through the second CL 61 passes through the optical path L2d as substantially parallel light and reaches the dichroic mirror 63.

  The linearly polarized S-wave second-wavelength laser light that is irradiated onto the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is substantially transmitted through the front side surface 63a of the substantially dichroic second dichroic mirror 63 and second. Enters the dichroic mirror 63. For example, approximately 92 to 98% of the linearly polarized S-wave second-wavelength laser light that has entered the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is approximately triangular. The light is reflected at a substantially right angle by the back side surface 63 b of the columnar second dichroic mirror 63 and travels along the optical path L <b> 2 e toward the second QWP 67. Further, for example, approximately 2 to 8% of the second-wavelength laser light of the linearly polarized S wave incident on the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is The light is emitted from the rear side surface 63b of the substantially triangular prism-shaped second dichroic mirror 63 by being bent at an obtuse angle and travels toward the second FMD 65 along the optical path L2g.

  More specifically, approximately 93 to 97% of linearly polarized S-wave second-wavelength laser light that has entered the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d. Are reflected at substantially right angles on the back side surface 63 b of the substantially triangular prism-shaped second dichroic mirror 63 and travel on the optical path L <b> 2 e toward the second QWP 67. Further, approximately 3-7% of the linearly polarized S-wave second-wavelength laser light that has entered the second dichroic mirror 63 from the front side surface 63a of the second dichroic mirror 63 through the optical path L2d is approximately triangular. It is bent and emitted from the back side surface 63b of the columnar second dichroic mirror 63 so as to form an obtuse angle, and travels along the optical path L2g toward the second FMD 65.

  Reflection of linearly polarized S-wave second-wavelength laser light on the second dichroic mirror 63 when the second-wavelength laser light of linearly-polarized S-wave is applied to the special film 63c on the back side surface 63b of the second dichroic mirror 63. When the amount is, for example, 92%, specifically less than 93%, that is, the transmission amount of the second wavelength laser light of the linearly polarized S wave in the second dichroic mirror 63 is, for example, 8%, specifically, more than 7%. In many cases, the amount of light necessary for irradiating the optical disc 200 (FIG. 2B) with the second wavelength laser light is insufficient.

The linearly polarized light S is applied to the special film 63c on the back side surface 63b of the second dichroic mirror 63 (FIG. 1).
When the second wavelength laser beam of the wave is applied, the reflection amount of the second wavelength laser beam of the linearly polarized S wave on the second dichroic mirror 63 is, for example, 98%, specifically more than 97%, that is, When the transmission amount of the linearly polarized S-wave second-wavelength laser light in the second dichroic mirror 63 is less than 2%, specifically 3%, for example, the second-wavelength laser light required for the second FMD 65 The amount of received light is insufficient.

  Reflection of linearly polarized S-wave second-wavelength laser light on the second dichroic mirror 63 when the second-wavelength laser light of linearly-polarized S-wave is applied to the special film 63c on the back side surface 63b of the second dichroic mirror 63. When the amount is, for example, 95%, that is, when the transmission amount of the second-wavelength laser light of the linearly polarized S wave in the second dichroic mirror 63 is, for example, 5%, the optical disc 200 (FIG. 2B) A sufficient amount of laser light is irradiated and an appropriate amount of laser light required for the second FMD 65 (FIG. 1) is irradiated. Therefore, it is preferable that the OPU 1 is equipped with the second dichroic mirror 63 having such characteristics.

  The dichroic film 63c of the dichroic mirror 63 reflects most of the linearly polarized S-wave laser beam for CD (second wavelength laser beam) having a wavelength of about 765 to 830 nm. When the second-wavelength laser light having a wavelength of 765 to 830 nm of the linearly polarized S wave is applied to the second dichroic mirror 63, the second dichroic mirror 63 causes the second-wavelength laser light having the most wavelength of 765 to 830 nm. Is reflected, and a part of the second wavelength laser beam having a wavelength of 765 to 830 nm is transmitted.

  The obtuse angle from the back side surface 63b of the substantially triangular prism-shaped second dichroic mirror 63 is incident on the second dichroic mirror 63 through the front side surface 63a of the substantially triangular prism-shaped second dichroic mirror 63, and passes through the second dichroic mirror 63. A part of the second-wavelength laser light that is bent and emitted so as to pass through the optical path L2g reaches the second FMD 65.

  Most of the second wavelength laser light reflected from the rear side surface 63b of the substantially triangular prism-shaped second dichroic mirror 63 at a substantially right angle reaches the second QWP 67 through the optical path L2e. The second wavelength laser beam reflected by the back side surface 63 b of the substantially triangular prismatic dichroic mirror 63 enters the second QWP 67 adjacent to the dichroic mirror 63. The linearly polarized S-wave second wavelength laser light transmitted through the second QWP 67 is circularly polarized light. In the second QWP 67, the linearly polarized S-wave second wavelength laser light becomes, for example, left-handed circularly polarized light.

  The second QWP 67 is not located in the optical path L2a, L2c, L2d from the second LD 20 to the second dichroic mirror 63 constituting the hologram laser diode unit 22, and the second OBL 70 is moved from the second dichroic mirror 63 to the second OBL 70. When the second QWP 67 (FIG. 1) is positioned in any one of the optical paths L2e and L2fc of the optical path L2e or L2fc (FIG. 2B) until passing through, for example, the second dichroic mirror 63 is moved. It is easy to avoid that part of the second-wavelength laser light that has passed through adversely affects the second FMD 65.

  The second wavelength laser beam that has passed through the second QWP 67 and turned into circularly polarized left-handed light passes through the optical path L2e, and is the second reflectivity located above the housing base wall reference portion 7h (FIG. 2B). Applied to MR68. Since the second reflective MR 68 is provided with the coating 68a that substantially totally reflects the laser light, the laser light applied to the reflective MR 68 is substantially totally reflected.

The second-wavelength laser light that has passed through the second QWP 67 (FIG. 1) and turned into left-handed circularly polarized light passes through the optical path L2e and reflects the reflective MR 68 (FIG. 2 (B)) at a slightly acute angle from a right angle. Then, the light passes through the aperture limiting element 69 through the optical path L2fc. When the second wavelength laser beam having a wavelength of about 765 to 830 nm for CD passes through the aperture limiting element 69, the phase correction of the second wavelength laser beam is performed. On the first side surface 69a of the aperture limiting element 69, a part of the infrared laser beam for CD (second wavelength laser beam) having a wavelength of about 765 to 830 nm is masked to be blocked. A special film 69c that transmits the blue-violet laser beam (first wavelength laser beam) for "and the red laser beam for DVD (third wavelength laser beam) having a wavelength of about 630 to 685 nm without masking. Therefore, when the second wavelength laser light passes through the aperture limiting element 69, the second wavelength laser light enters the OBL 70 in a masked state and is narrowed down by the OBL 70.

  Thereby, the second wavelength laser beam is narrowed down by the OBL 70 in the same state as being narrowed down by an OBL (not shown) having a numerical aperture of about 0.45. The actual numerical aperture of the OBL 70 is approximately 0.6 or 0.65. However, if the aperture limiting element 69 is provided in the optical path, the second wavelength laser light enters the OBL 70 in a masked state. Therefore, the second wavelength laser beam is focused on the signal unit 250 of the optical disk for CD 200 in the same state as being narrowed down using an OBL (not shown) having a numerical aperture of about 0.45. By providing the aperture limiting element 69 in the optical path, even if one OBL 70 having a numerical aperture of about 0.6 to 0.65 is used, the OBL 70 has a numerical aperture of about 0.37 to 0.95, for example. It functions substantially as a numerical aperture of about 0.45 to 0.65. The left-turn circularly polarized second wavelength laser light is applied by the special film 69c formed on the first side surface 69a of the aperture limiting element 69 when it enters the aperture limiting element 69 from the first side surface 69a of the aperture limiting element 69. Masked and emitted from the second side surface 69b of the aperture limiting element 69 in the masked state.

  Depending on the design / specifications of the OPU 1, for example, a special film (69c) may be provided on the second side surface (69b) of the aperture limiting element (69). Further, in place of the opening limiting element 69 in which the special film 69c is formed on the first side surface 69a, for example, an opening limiting element (69) in which the special film (69c) is formed on the second side surface (69b) can be used. The

  The left-turn circularly polarized second-wavelength laser light transmitted through the aperture limiting element 69 passes through the second OBL 70. The left-handed circularly polarized second-wavelength laser light that is substantially parallel light becomes convergent light by the second OBL 70 and is applied to the signal portion 250 of the optical disk 200 of the CD standard.

  When the focus servo of the second OBL 70 mounted on the lens holder (not shown) is performed on the optical disc 200, the lens holder including the second OBL 70 is moved along the focus direction Df. Further, when the tracking servo of the second OBL 70 mounted on the lens holder (not shown) is performed on the optical disc 200, the lens holder including the second OBL 70 is moved along the tracking direction Dr. Further, when tilt control of the second OBL 70 mounted on the lens holder is performed on the optical disc 200, the lens holder including the second OBL 70 is swung along the tilt direction Dt.

  The second wavelength laser light of the diffused light emitted from the second LD 20 (FIG. 1) is converted into a linearly polarized S wave by the second DOE 21 in the optical path L2a, and is changed from the diffused light to the substantially parallel light by the second CL 61 in the optical path L2d. The second QWP 67 in the optical path L2e is converted to a left-turn circularly polarized light from the linearly polarized S wave, masked by the aperture limiting element 69 in the optical path L2fc (FIG. 2B), and converged by the second OBL 70, The light is focused on the signal section 250 of the CD standard optical disc 200. The laser beam of the second wavelength follows the forward path in this way, and is focused on the CD standard optical disc 200 as the second medium 200.

Next, the return path of the second wavelength laser beam reflected from the CD standard optical disc 200 will be described. When the second wavelength laser light is reflected by the signal unit 250 of the CD standard optical disc 200, the left-handed circularly polarized second-wavelength laser light becomes right-handed circularly polarized light. The right-turn circularly polarized second-wavelength laser light becomes diffused light, returns through the optical path L2fc, and reaches the second OBL 70. The right-handed circularly polarized second-wavelength laser light that is diffused light becomes substantially parallel light by the second OBL 70. The right-turn circularly polarized second-wavelength laser light that passes through the second OBL 70 and returns to the optical path L2fc passes through the aperture limiting element 69 and reaches the second reflective MR 68.

  The right-turn circularly polarized second wavelength laser light reflected from the second reflective MR 68 returns to the second QWP 67 through the optical path L2e (FIG. 1). When the second wavelength laser light returns through the optical path L2e and passes through the second QWP 67, the right-turn circularly polarized second wavelength laser light becomes a linearly polarized P wave. The linearly polarized P-wave second-wavelength laser light transmitted through the second QWP 67 enters the second dichroic mirror 63 adjacent to the second QWP 67.

  The linearly polarized P-wave second-wavelength laser light internally reflected by the back side surface 63b of the second dichroic mirror 63 returns to the second CL 61 through the optical path L2d. When the second wavelength laser beam returns through the optical path L2d and passes through the second CL 61, the second wavelength laser beam of the substantially parallel linearly polarized P wave is the second wavelength laser beam of the linearly polarized P wave of the convergent light. It becomes. The linearly polarized P-wavelength second-wavelength laser light transmitted through the second CL 61 returns to the liquid crystal correction element 52 through the optical path L2d. The linearly polarized P-wavelength second-wavelength laser light transmitted through the liquid crystal correction element 52 returns to the PBS 40 through the optical path L2d.

  Since the special film 40c that allows the second wavelength laser light to pass straightly through the PBS 40 is provided in the PBS 40, the second wavelength laser light of the linearly polarized P wave that has returned the optical path L2d and reached the PBS 40 is substantially passed through the PBS 40. Go straight and pass through the optical path L2c and reach the PBS 25.

  The linearly-polarized P-wavelength second-wavelength laser light that has entered the PBS 40 from the optical path L2d is transmitted through the PBS 40 substantially straight, then exits the PBS 40, and enters the PBS 25 through the optical path L2c. The PBS 25 is configured to reflect the second wavelength laser light having a wavelength of about 765 to 830 nm in the PBS 25.

  By the PBS 25 having the special coating 25c, the CD laser light having a wavelength of about 765 to 830 nm incident on the PBS 25 is internally reflected so as to have an obtuse angle, passes through the PBS 25, and is emitted from the PBS 25. The linearly polarized P-wavelength second-wavelength laser light internally reflected so as to form an obtuse angle in the PBS 25 passes through the divergent lens 23 through the optical path L2a and reaches the DOE 21. When the linearly polarized P-wavelength second-wavelength laser light passing through the optical path L2a passes through the DOE 21, the second-wavelength laser light is bent so that the optical path of the second-wavelength laser light has an obtuse angle, and the direction of the second-wavelength laser light is changed. The polarized P-wavelength second-wavelength laser light passes through the optical path L2h. The second wavelength laser light transmitted through the DOE 21 passes through the optical path L2h and reaches the light detection unit 20b provided in the metal cover 20c constituting the LD 20.

  The light detection unit 20b receives the laser beam reflected from the optical disc 200 (FIG. 2B), converts the signal into an electrical signal, and detects information recorded on the optical disc 200 (FIG. 2B). It is meant for. The light detection unit 20b (FIG. 1) receives the laser beam reflected from the optical disc 200 (FIG. 2B), converts the signal into an electrical signal, and has an OBL with OPU 1 (FIG. 1). A servo mechanism (not shown) of a lens holder (not shown) is operated. Here, for convenience, the light detection unit is abbreviated as, for example, “PD” or “PDIC”.

The diffused second wavelength laser light reflected by the signal unit 250 of the CD standard optical disc 200 (FIG. 2B) is reflected from the left-handed circularly polarized light when reflected by the signal unit 250 of the optical disc 200. Right-handed circularly polarized light becomes substantially parallel light by the second OBL 70 in the optical path L2fc, and right-handed circularly polarized light becomes linearly polarized P-wave by the second QWP 67 (FIG. 1) in the optical path L2e. The second CL 61 changes the light from substantially parallel light to converged light and irradiates the PDIC 20b positioned at the end of the optical path L2h. The second-wavelength laser light reflected from the CD-standard optical disk 200 (FIG. 2B) follows the return path in this way, and the second PDIC 20b mounted in the metal cover 20c constituting the LD 20 (FIG. 1). Is irradiated.

  The LDD 9, LD 10, 30, the PDIC 20b, the hologram laser diode unit 22 including the LD 20 having the light emitting portion 20a, the LCD 37, the expander unit 45, the FMD 50, 65, the PDIC 90A, etc. A flexible substrate 8A such as a circuit body is connected to be energized. The flexible printed circuit is abbreviated as “FPC”. In the FPC 8A, a plurality of circuit conductors (not shown) are printed on an insulating sheet (not shown) made of an aromatic heat resistant resin such as a wholly aromatic polyimide resin, for example, and a metal foil such as a copper foil (not shown) (Not shown) are arranged side by side on the insulating sheet, and a transparent or translucent protective layer (not shown) made of an aromatic heat-resistant resin such as a wholly aromatic polyimide resin is provided thereon. The By using FPC8A including an insulating sheet made of aromatic heat-resistant resin such as wholly aromatic polyimide resin and / or a protective layer, LD20 having LDD9, LD10, 30, PDIC20b and light emitting portion 20a is provided for FPC8A. The holographic laser diode unit 22, the LCD 37, the expander unit 45, the FMDs 50 and 65, the PDIC 90A, and the like provided with the above are favorably soldered. The FPC 8A is configured as, for example, a standardized FPC 8A that can be used in common with other OPUs.

  The OPU 1 includes the above-described various types. Various parts constituting the OPU 1 are mounted on a metal housing 7A. The housing 7A is a side view of a pair of main shafts that is movably fitted to a housing main body 7d equipped with various components and a substantially straight round bar-shaped first shaft member (not shown) that protrudes from the housing main body 7d. A bearing portion 7p, 7q having a round hole shape and a second shaft having a substantially straight round bar shape projecting from the housing body 7d toward the opposite side to the bearing portions 7p, 7q having a substantially round hole shape in a side view for the main shaft. It is formed with a member (not shown) and a bearing portion 7r having a substantially U shape in side view for a counter shaft that is movably matched. The main shaft bearing portions 7p and 7q and the sub shaft bearing portion 7r are integrally formed with the housing body 7d. The main shaft bearing portions 7p and 7q, the sub shaft bearing portion 7r, and the housing body 7d are formed as a single piece using the same metal material.

  For the housing 7A constituting the OPU 1, for example, a non-ferrous metal such as aluminum (Al), magnesium (Mg), and zinc (Zn), or an alloy containing aluminum (Al), magnesium (Mg), and zinc (Zn) is used. Formed. Aluminum, magnesium, and zinc are excellent in corrosion resistance and are non-ferrous metals having a specific gravity smaller than that of iron. For example, an aluminum alloy containing aluminum as a main component is used to form the housing 7A. For example, the heat generated from the plurality of LDs 10, 20, 30 and the like is efficiently dissipated outside the housing 7A by the aluminum alloy housing 7A mainly composed of aluminum having excellent heat dissipation. The housing 7A is made of aluminum and is formed as, for example, a standardized housing 7A that can be used in common with other OPUs. The OPU 1 including the housing 7A and the like is assumed to include other components in addition to those illustrated, but in FIG. 1, these other components are omitted for convenience.

  For example, when the optical disk apparatus is turned on and the optical disk apparatus is activated, the optical disk 100 (FIG. 2A, FIG. 3A), 200 (FIG. 2B), 300 (FIG. 3 (B)), when the track jump of the OPU 1 (FIG. 1) is performed, the OPU 1 movably supported by the first shaft member and the second shaft member each having a substantially straight round bar shape is substantially in the disk radial direction Dr. Driven along. The OPU 1 is mounted on the first shaft member and the second shaft member that are substantially linear round bar-shaped in a state that can reciprocate substantially along the disk radial direction Dr.

  The OPU 1 includes the housing 7A, the FPC 8A, the LDD 9, the LD 10, 30, the DOE 11, 21, 31, the hologram laser diode unit 22, the divergent lens 23, the PBS 25, 35, 40, the LCD 37, CL41, 61, the beam expander unit 45, the dichroic mirrors 48, 63, the FMD 50, 65, the liquid crystal correction element 52, the QWP 57, 67, the MR 58, 68, the OBL 60, 70, the aperture limiting element 69, The sensor lens 80A, the PDIC 90A, and the like are provided.

  The OPU 1 is used to irradiate the CD-series optical disc 200 (FIG. 2B) with laser light and the DVD-series optical disc 300 (FIG. 3B). When compared with the current state, on the optical axes LA1 and LA2 along the focus direction Df, the focal positions of the spots S2 and S3 of the laser beams irradiated and formed on the signal portions 250 and 350 of the optical discs 200 and 300 are different. . In addition, the working distance WDc of the second objective lens 70 with respect to the CD-series optical disc 200 (FIG. 2B) and the working distance of the second objective lens 70 with respect to the DVD-series optical disc 300 (FIG. 3B) ( WDd). For example, the working distance WDc of the second objective lens 70 for the CD-series optical disc 200 (FIG. 2B) is approximately 0.61 mm. For example, the working distance (WDd) of the second objective lens 70 with respect to the DVD series optical disc 300 (FIG. 3B) is about 0.84 mm.

  Further, as shown in FIG. 3, a state in which laser light is applied to the “HD DVD” series optical disc 300 as a DVD series optical disc 300 and a case in which laser light is applied to the Blu-ray Disc series optical disc 100. When compared with the state, the focal positions of the laser beam spots S3 and S1 irradiated on the signal portions 350 and 150 of the optical disks 300 and 100 on the optical axes LA1 and LA2 along the focus direction Df are different. Also, the working distance WDd of the second objective lens 70 for the DVD series optical disc 300 is different from the working distance WDb of the first objective lens 60 for the Blu-ray Disc series optical disc 100. For example, the working distance WDb of the first objective lens 60 for the Blu-ray Disc series optical disc 100 is about 0.36 mm. Further, for example, the working distance WDd of the second objective lens 70 for the “HD DVD” optical disc 300 (FIG. 3B) is approximately 0.76 mm.

  Further, as shown in FIG. 2, when the state when the laser light is irradiated onto the Blu-ray Disc optical disc 100 and the state when the laser light is irradiated onto the CD optical disc 200, the focus direction Df is compared. The focal positions of the laser light spots S1 and S2 formed on the signal portions 150 and 250 of the optical disks 100 and 200 are different on the optical axes LA1 and LA2. Also, the working distance WDb of the first objective lens 60 for the Blu-ray Disc series optical disc 100 is different from the working distance WDc of the second objective lens 70 for the CD series optical disc 200.

  Since the optical discs 100 (FIG. 2A, FIG. 3A), 200 (FIG. 2B), and 300 (FIG. 3B) have different standards, the optical axis LA1 along the focus direction Df. , LA2 and the focal positions of the laser light spots S1, S2, S3, working distances WDb, WDc, WDd, (WDd) and the like are different, but the OPU 1 shown in FIG. It is possible to cope with different optical disks 100, 200, and 300.

The OPU 1 includes a first LD 10 capable of emitting a first wavelength laser beam, a second LD 20 capable of emitting a second wavelength laser beam having a wavelength different from the first wavelength laser beam, and a first wavelength laser beam. A first OBL 60 for condensing on one optical disc 100 and a second OBL 70 for condensing the second wavelength laser light on a second optical disc 200 which is an optical disc of a standard different from the first optical disc 100 are provided.

  For convenience, the optical paths L1i and L1ii of the first wavelength laser light from the first LD 10 to the first optical disc 100 via the first OBL 60 are defined as the first optical path L1. Further, the optical paths L2i and L2ii of the second wavelength laser light from the second LD 20 to the second optical disc 200 via the second OBL 70 are defined as the second optical path L2 for convenience. When the first optical path L1 and the second optical path L2 are thus defined and the OPU 1 is viewed in plan as shown in FIG. 1, the optical layout in the OPU 1 is that the first optical path L1 and the second optical path L2 are within the housing 7A. For example, the optical layout is substantially cross-shaped and intersects at a substantially right angle.

  By configuring the optical layout in this manner, even if the standard of the first optical disc 100 and the standard of the second optical disc 200 are different, at least the first optical disc 100 and the optical disc having a different standard from the first optical disc 100 are used. The OPU 1 corresponding to the second optical disc 200 can be provided.

  The first LD 10 capable of emitting the first wavelength laser light, the second LD 20 capable of emitting the second wavelength laser light having a wavelength different from the first wavelength laser light, and the first wavelength laser light on the first optical disc 100 If the OPU 1 is configured to include the first OBL 60 that condenses the light and the second OBL 70 that condenses the second wavelength laser light on the second optical disc 200 that is an optical disc of a standard different from the first optical disc 100, A single OPU 1 can at least correspond to, for example, a first optical disc 100 with a high-density recording standard and a second optical disc 200 with a conventional standard different from the first optical disc 100. Accordingly, it is possible to provide the OPU 1 corresponding to the various optical discs 100 and 200 of different standards.

  Further, the first optical path L1 which is the optical path L1i, L1ii of the first wavelength laser light from the first LD 10 to the first optical disc 100 via the first OBL 60 and the second LD 20 via the second OBL 70. An optical layout in which the second optical path L2 defined as the optical paths L2i and L2ii of the second wavelength laser light until reaching the second optical disc 200 intersects the housing 7A at a substantially right angle, for example, in a cross shape in plan view. By doing so, the OPU 1 can be reduced in size and thickness. Accordingly, it is possible to provide the OPU 1 with space saving. Further, when the OPU 1 is viewed in a plan view, the first optical path L1 and the second optical path L2 are, for example, substantially cross-shaped and substantially perpendicular to each other in the housing 7A, whereby the OPU 1 in the housing 7A. Optical layout design is facilitated.

  The OPU 1 guides the first wavelength laser light to the optical path L1ii reaching the first optical disc 100 via the first OBL 60 or the optical path L2ii reaching the third optical disc 300 via the second OBL 70, and A PBS 40 is provided for guiding the second wavelength laser light to the optical path L2ii that reaches the second optical disk 200 via the optical path L2ii.

By mounting the PBS 40 on the OPU 1, it becomes possible to configure the OPU 1 corresponding to various optical discs 100, 200, and 300 of different standards. When the PBS 40 is installed in the OPU 1, the first wavelength laser light emitted from the first LD 10 is guided to the optical path L 1 ii reaching the first optical disc 100 via the first OBL 60. Alternatively, the first wavelength laser beam emitted from the first LD 10 reaches the third optical disc 300 that is changed from the first optical disc 100 to the optical disc different from the second optical disc 200 via the second OBL 70. Guided to the optical path L2ii. Further, when the PBS 40 is installed in the OPU 1, the second wavelength laser light emitted from the second LD 20 is guided to the optical path L 2 ii reaching the second optical disc 200 via the second OBL 70. By mounting the PBS 40 corresponding to at least the first wavelength laser beam and the second wavelength laser beam on the OPU 1, the OPU 1 can support various optical discs 100, 200, and 300.

  When the first wavelength laser light passes through the PBS 40 substantially straight, the first wavelength laser light emitted from the first LD 10 is condensed on the first optical disc 100 via the first OBL 60. In addition, when the first wavelength laser light is internally reflected substantially at right angles by the PBS 40, the first wavelength laser light emitted from the first LD 10 is condensed on the third optical disc 300 via the second OBL 70. Is done.

  The first wavelength laser light emitted from the first LD 10 by the PBS 40 is condensed on the first optical disc 100 by the first OBL 60. Alternatively, the first wavelength laser beam emitted from the first LD 10 by the PBS 40 is changed to an optical disc different from the first optical disc 100 and to an optical disc different from the second optical disc 200 by the second OBL 70. It is focused on. The first optical disc 100 or the first optical disc 100 and the second optical disc 200 are utilized by utilizing the transmission characteristic with respect to the first wavelength laser light provided in the PBS 40 or the reflection characteristic with respect to the first wavelength laser light provided in the PBS 40. It becomes possible to focus the first wavelength laser beam on the different third optical disc 300.

  The second wavelength laser light emitted from the second LD 20 is guided to the optical path L2ii reaching the second optical disc 200 via the second OBL 70 by the PBS 40.

  By mounting the PBS 40 having the above performance on the OPU 1, the OPU 1 corresponding to the various optical discs 100, 200, and 300 having different standards is configured. By installing PBS 40 that guides the second wavelength laser beam to the optical path L2ii reaching the second optical disc 200 via the second OBL 70, the OPU 1 can support various optical discs 100, 200, and 300. Become.

  The second wavelength laser light emitted from the second LD 20 passes through the PBS 40 substantially straight and is condensed on the second optical disc 200 via the second OBL 70.

  The second wavelength laser light emitted from the second LD 20 is condensed on the second optical disc 200 by the second OBL 70. It is possible to focus the second wavelength laser light on the second optical disc 200 by using the substantially straight transmission characteristic of the second wavelength laser light included in the PBS 40.

  In the housing 7A, the PBS 40 passes through the first optical path L1 from the first LD 10 to the first optical disc 100 via the first OBL 60, and the first optical path L1 from the second LD 20 via the second OBL 70. It is located at the optical path intersection LX where the second optical path L2 defined as the optical paths L2i and L2ii to the second optical disc 200 intersects.

  This makes it possible to reduce the size and thickness of the OPU 1 that can be used for various optical discs 100, 200, and 300. A first optical path L1 which is an optical path L1i, L1ii from the first LD 10 to the first optical disc 100 via the first OBL 60, and an optical path L2i from the second LD 20 to the second optical disc 200 via the second OBL 70, By positioning the PBS 40 at the optical path intersection LX where the second optical path L2 that is L2ii intersects, the optical layout in the OPU 1 can be made compact. Therefore, it is possible to provide a small / thin OPU 1 that can handle various optical discs 100, 200, and 300.

When the first wavelength laser beam passing through the PBS 40 is changed to a P wave, the first wavelength laser beam passes through the PBS 40 substantially straight and is condensed on the first optical disc 100 via the first OBL 60. The

  The P-wavelength first-wavelength laser light is transmitted through the PBS 40 substantially straight, passes through the first OBL 60, and is reliably condensed on the first optical disc 100. The first wavelength laser light that has passed through the PBS 40 is changed to a P wave, and the polarization state of the first wavelength laser light is clarified. Since the PBS 40 is formed to transmit the P-wavelength first wavelength laser light substantially straightly, the P-wavelength first-wavelength laser light surely transmits substantially straight through the PBS 40 and passes through the first OBL 60. The light is surely collected on the first optical disc 100.

  When the first wavelength laser beam passing through the PBS 40 is changed to an S wave, the first wavelength laser beam is internally reflected at a substantially right angle by the PBS 40 and collected on the third optical disc 300 via the second OBL 70. Lighted.

  The S-wavelength first-wavelength laser light is reflected substantially at right angles in the PBS 40, passes through the second OBL 70, and is reliably condensed on the third optical disc 300 different from the first optical disc 100 and the second optical disc 200. . The first wavelength laser beam that has passed through the PBS 40 is changed to an S wave, and the polarization state of the first wavelength laser beam is clarified. The PBS 40 is formed so as to internally reflect the S-wavelength first wavelength laser light at a substantially right angle, so that the S-wavelength first wavelength laser light is reliably reflected within the PBS 40 at a substantially right angle, The light is reliably condensed on the third optical disc 300 via the OBL 70.

  The OPU 1 includes a polarization direction conversion member 37 capable of polarizing S-wave or P-wave first wavelength laser light in the optical path L1c of the first optical path L1.

  Since the polarization direction changing member 37 is installed in the OPU 1, the first wavelength laser light emitted from the first LD 10 passes through the first OBL 60 through the optical path L 1 ii reaching the first optical disc 100 or the second OBL 70. Via the optical path L2ii reaching the third optical disk 300 different from the first optical disk 100 and the second optical disk 200 via the optical path L2ii. Using the polarization direction conversion member 37 positioned in the optical path L1c of the first optical path L1, the polarization state of the first wavelength laser light is changed to P wave or S wave, or the polarization state of the first wavelength laser light is changed to P wave. Alternatively, by leaving the S wave as it is, the first wavelength laser light is transmitted through the PBS 40 or reflected internally from the PBS 40, for example. When the first wavelength laser light is internally transmitted or internally reflected through the PBS 40, the first wavelength laser light passes through the first OBL 60 and reaches the first optical disc 100 or the second OBL 70 through the second optical path L 1 ii. Three are reliably directed to the optical path L2ii reaching the optical disc 300.

  The polarization direction changing member 37 is located in the optical path L1i between the first LD 10 and the PBS 40. More specifically, the polarization direction changing member 37 is located in the optical path L1c between the PBS 35 and the PBS 40.

By thus arranging the polarization direction changing member 37 in the housing 7A, the optical path change of the first wavelength laser light in the PBS 40 is reliably performed. A first wavelength emitted from the first LD 10 by positioning a polarization direction changing member 37 capable of polarizing S-wave or P-wave first wavelength laser light in the optical path L1i between the first LD 10 and the PBS 40. The laser light is surely in a desired polarization state such as a P wave or an S wave before the first wavelength laser light is incident on the PBS 40. More specifically, the polarization direction conversion member 37 capable of polarizing S-wave or P-wavelength first laser light is positioned in the optical path L1c between the PBS 35 and the PBS 40, whereby the first LD 10 emitted from the first LD 10 is positioned. The one-wavelength laser light is surely in a desired polarization state such as a P wave or an S wave before the first wavelength laser light is incident on the PBS 40. Alternatively, the polarization state of the first wavelength laser light is reliably incident on the PBS 40 with the P wave or S wave. Since the polarization state of the first wavelength laser light can be determined in advance before the first wavelength laser light is incident on the PBS 40, the first wavelength laser light emitted from the first LD 10 The optical path L1ii reaching the first optical disc 100 via the first OBL 60 or the optical path L2ii reaching the third optical disc 300 different from the first optical disc 100 and the second optical disc 200 via the second OBL 70 Be turned to.

  As the polarization direction converting member 37, an LCD 37 is used that can freely polarize S-wave or P-wavelength first laser light into P-wave or S-wavelength first laser light when energized. More specifically, the OPU 1 is equipped with an LCD 37 that can freely polarize a P-wavelength first laser beam into an S-wavelength first laser beam when energized.

  By using the LCD 37 as the polarization direction changing member 37, the S-wave or P-wave first wavelength laser light is freely polarized into the P-wave or S-wave first wavelength laser light. Alternatively, without changing the polarization state of the first wavelength laser light, the P-wave or S-wave first wavelength laser light is left as the P-wave or S-wave first wavelength laser light. More specifically, for example, when electricity is not applied to the LCD 37, the P-wavelength first laser beam incident on the LCD 37 is emitted from the LCD 37 as the P-wavelength first laser beam. In this case, for example, the P-wavelength first-wavelength laser light travels substantially straight through the PBS 40 and reaches the first OBL 60, and is condensed on the first optical disc 100 by the first OBL 60. Further, for example, when electricity flows through the LCD 37, the P-wavelength first wavelength laser light incident on the LCD 37 is polarized into the S-wavelength first wavelength laser light and emitted from the LCD 37. In this case, for example, the S-wavelength first wavelength laser light is internally reflected substantially at right angles by the PBS 40 and reaches the second OBL 70, and the third optical disk 300 different from the first optical disk 100 and the second optical disk 200 by the second OBL 70. Focused on top.

  The OPU 1 includes a third LD 30 capable of emitting a third wavelength laser beam having a wavelength different from that of the first wavelength laser beam and a wavelength different from that of the second wavelength laser beam.

  Since the third LD 30 is mounted on the OPU 1, the OPU 1 has a third optical disc 300 corresponding to a third wavelength laser beam having a wavelength different from that of the first wavelength laser beam and a wavelength different from that of the second wavelength laser beam. Can also be supported. Therefore, it is possible to provide the OPU 1 corresponding to various optical discs 100, 200, 300 such as the first optical disc 100, the second optical disc 200, and the third optical disc 300.

  The PBS 40 for guiding the first wavelength laser beam to the optical path L1ii reaching the first optical disc 100 via the first OBL 60 or the optical path L2ii reaching the third optical disc 300 via the second OBL 70 causes the second wavelength laser beam to be Then, the light is guided to the optical path L2ii reaching the second optical disc 200 via the second OBL 70. Further, the third wavelength laser is provided by the PBS 40 for guiding the first wavelength laser light to the optical path L1ii reaching the first optical disc 100 via the first OBL 60 or the optical path L2ii reaching the third optical disc 300 via the second OBL 70. The light is guided through the second OBL 70 to an optical path L2ii that reaches the third optical disc 300.

Since the OPU 1 is equipped with the PBS 40 having the performance of guiding some of the second wavelength laser light, the second wavelength laser light, and the third wavelength laser light to the optical path L2ii, various optical disks 100, 200, OPU1 corresponding to 300 is configured. By mounting the PBS 40 having the above performance on the OPU 1, the first wavelength laser light emitted from the first LD 10 is guided to the optical path L 1 ii reaching the first optical disc 100 via the first OBL 60. Or the 1st wavelength laser beam radiate | emitted from 1st LD10 is guide | induced to the optical path L2ii which reaches the 3rd optical disk 300 via 2nd OBL70. In addition, since the PBS 40 having the above performance is equipped in the OPU 1, the second wavelength laser light emitted from the second LD 20 is
The light is guided to the optical path L2ii reaching the second optical disc 200 via the second OBL 70. In addition, by mounting the PBS 40 having the above performance on the OPU 1, the third wavelength laser light emitted from the third LD 30 is guided to the optical path L 2 ii reaching the third optical disc 300 via the second OBL 70. By mounting the PBS 40 corresponding to the first wavelength laser beam, the second wavelength laser beam, and the third wavelength laser beam on the OPU 1, the OPU 1 can support various optical disks 100, 200, and 300. .

  The third wavelength laser light emitted from the third LD 30 is internally reflected at a substantially right angle by the PBS 40 and is condensed on the third optical disc 300 via the second OBL 70.

  The third wavelength laser light emitted from the third LD 30 is condensed on the third optical disc 300 by the second OBL 70. The third wavelength laser light can be condensed on the third optical disc 300 by using the reflection characteristic of the PBS 40 with respect to the third wavelength laser light.

  The third wavelength laser light emitted from the third LD 30 is changed to an optical disc with a different standard from the first optical disc 100 by the second OBL 70 and onto an optical disc 300 with a different standard from the second optical disc 200. Focused.

  The OPU 1 corresponds to various optical discs 100, 200, and 300 including the third optical disc 300 corresponding to the third wavelength laser light. The OPU 1 includes a first optical disc 100 corresponding to the first wavelength laser beam, an optical disc having a different standard from the first optical disc 100, a second optical disc 200 corresponding to the second wavelength laser beam, and a standard different from the first optical disc 100. And an optical disc of a standard different from that of the second optical disc 200, and can be adapted to the third optical disc 300 corresponding to the third wavelength laser beam. For example, the first optical disc 100 is a high-density recording standard optical disc that is not compatible with a conventional standard optical disc, the second optical disc 200 is a conventional standard optical disc, and the third optical disc 300 is more than the second optical disc 200. Even if the optical disk is a high-density recording standard optical disk and includes a conventional optical disk different from the second optical disk 200, the OPU 1 includes the first optical disk 100, the second optical disk 200, and the third optical disk 300. Corresponding to

  As shown in FIG. 1, the OPU 1 includes a first LD 10 capable of emitting a first wavelength laser beam, and a second wavelength laser having a wavelength different from the first wavelength laser beam emitted from the first LD 10. A second LD 20 capable of emitting light, a wavelength different from the first wavelength laser light emitted from the first LD 10 and a wavelength different from the second wavelength laser light emitted from the second LD 20. The third LD 30 capable of emitting the third wavelength laser light and the first wavelength laser light emitted from the first LD 10 are transmitted substantially linearly or reflected at a substantially right angle and emitted from the second LD 20. The first wavelength laser light is collected on the first medium 100, and the PBS 40 reflects the third wavelength laser light emitted from the third LD 30 substantially at right angles. First OBL to light 0, and a second OBL 70 that condenses the laser light of the second wavelength on the second medium 200 and condenses the laser light of the first wavelength or the laser light of the third wavelength on the third medium 300, It is configured as a provision.

If the OPU 1 is configured in this way, even if the standard of the first medium 100, the standard of the second medium 200, and the standard of the third medium 300 are different from each other, The OPU 1 corresponding to the second medium 200 and the third medium 300 can be provided. For example, the first medium 100 is a new standard Blu-ray Disc standard medium that is capable of high-density recording while being incompatible with the conventional standard, and the second medium 200 is compatible with the conventional standard. If the third medium 300 is a DVD standard medium corresponding to the conventional standard, the first medium 100, the second medium 200, and the third medium 300 can be compatible with completely different standards. It has been difficult to develop a simple OPU1.

  In order to cope with this, for example, a first OPU (not shown) corresponding to the first medium 100 and a second OPU (not shown) corresponding to the second medium 200 and the third medium 300 are included. An optical disk device (not shown) using two OPUs has also been considered. However, an optical disc apparatus in which a plurality of OPUs including a first OPU (not shown) corresponding to the first medium 100 and a second OPU (not shown) corresponding to the second medium 200 and the third medium 300 is used is a component. As the number of points increases, there is a concern that the size will increase, the weight will increase, and the price will become expensive.

  On the other hand, the first LD 10 capable of emitting the first wavelength laser light and the second wavelength laser light having a different wavelength from the first wavelength laser light emitted from the first LD 10 can be emitted. The second LD 20 and a third wavelength different from the first wavelength laser light emitted from the first LD 10 and different from the second wavelength laser light emitted from the second LD 20 The third LD 30 capable of emitting the laser light of the first wavelength and the laser light of the first wavelength emitted from the first LD 10 are transmitted substantially linearly or reflected at substantially right angles, and the second wavelength of the second wavelength emitted from the second LD 20 is reflected. A PBS 40 that transmits the laser light substantially straightly and reflects the laser light of the third wavelength emitted from the third LD 30 at a substantially right angle, and a first light that condenses the laser light of the first wavelength on the first medium 100. OBL60 and second wavelength If OPU1 provided with 2nd OBL70 which condenses a laser beam on the 2nd medium 200 and condenses the 1st wavelength laser beam or the 3rd wavelength laser beam on the 3rd medium 300 is comprised The first medium 100 of the Blu-ray Disc standard, which is a new high-density recording standard, and the second medium 200, which is compatible with the CD standard, which is completely different from the first medium 100, in a single OPU 1, It is possible to support the third medium 300 that is compatible with the DVD standard that is completely different from the one medium 100 and is different from the second medium 200 as the conventional standard. Accordingly, the OPU 1 corresponding to various media 100, 200, 300, etc. of different standards such as the Blu-ray Disc standard, the DVD standard, and the CD standard can be provided to the assembly manufacturer of the OPU 1, the user of the OPU 1, and the like.

  Depending on the design / specifications of the OPU (1), for example, the second LD (20) may be configured as an LD (20) capable of emitting laser beams of a plurality of types of wavelengths. More specifically, the second LD (20) emits a second wavelength laser beam and a third wavelength laser beam having a different wavelength from the first wavelength laser beam and a different wavelength from the second wavelength laser beam. It may be configured as a possible dual wavelength light emitting device (dual wavelength LD) (20). In this case, the third LD (30), the third DOE (31), and the third PBS (35) can be omitted without being installed in the OPU (1).

The OPU 1 that can handle various optical discs 100, 200, and 300 is configured by mounting the LD (20) capable of emitting laser beams of a plurality of types of wavelengths typified by the two-wavelength LD (20). In addition, the number of parts of the OPU 1 can be reduced. For example, the second LD (20) has two types of wavelengths: a second wavelength laser beam and a third wavelength laser beam that has a different wavelength from the first wavelength laser beam and a different wavelength from the second wavelength laser beam. Since it is configured as a two-wavelength LD (20) capable of emitting laser light, the OPU 1 equipped with the first LD 10 and the second LD (20) can support various optical discs 100, 200, and 300. At the same time, the LD 20 capable of emitting the second wavelength laser light and the LD 30 capable of emitting the third wavelength laser light are combined into one LD (20), and the third LD (30) and the third DOE are combined. Since (31) and the third PBS (35) are omitted without being installed in the OPU (1), the parts of the OPU 1 can be reduced, reduced in weight, reduced in size, reduced in weight, reduced in price, and the like. It will be. Accordingly, it is possible to provide an OPU (1) that can be used for various optical discs 100, 200, and 300 and that is reduced in parts, reduced in weight, reduced in size, reduced in thickness, reduced in price, and the like.

  The third wavelength laser light emitted from the second LD (20), which is the two-wavelength LD (20), follows, for example, the second optical path (L2) that is the same optical path as the optical path followed by the second wavelength laser light. The second OBL 70 focuses the light on the third optical disc 300 which is an optical disc having a different standard from the first optical disc 100 and an optical disc having a different standard from the second optical disc 200.

  The OPU (1) corresponds to various optical discs 100, 200, and 300 including the third optical disc 300 corresponding to the third wavelength laser light. The OPU (1) includes a first optical disc 100 corresponding to the first wavelength laser beam, a second optical disc 200 corresponding to the second wavelength laser beam, which is an optical disc of a standard different from the first optical disc 100, and the first optical disc 100. And an optical disc with a different standard from the second optical disc 200, and is compatible with the third optical disc 300 corresponding to the third wavelength laser beam. For example, the first optical disc 100 is a high-density recording standard optical disc that is not compatible with a conventional standard optical disc, the second optical disc 200 is a conventional standard optical disc, and the third optical disc 300 is more than the second optical disc 200. Even if the optical disc is a high-density recording standard optical disc and includes a conventional optical disc different from the second optical disc 200, the OPU (1) is composed of the first optical disc 100, the second optical disc 200, and the third optical disc. This corresponds to the optical disc 300.

  For example, when the two-wavelength LD (20) capable of emitting the second wavelength laser beam and the third wavelength laser beam constitutes the hologram laser diode unit (22), the second PBS (25) is included in the PBS (25). The second wavelength laser beam and the third wavelength laser beam are both internally reflected. In this case, the second wavelength laser beam and the third wavelength laser beam are internally reflected in the PBS (25) regardless of the P wave or S wave. In this case, the coating (25c) in the PBS (25) reflects the second wavelength laser beam and the third wavelength laser beam regardless of the P wave or S wave. The coating (25c) in the PBS (25) transmits the first wavelength laser light regardless of the P wave or S wave. The second wavelength laser light on the return path and the third wavelength laser light on the return path that are emitted from the PBS (40) after passing through the PBS (40) substantially straight and then return on the optical path (L2c) are both the second PBS (25 ) Is reflected at a substantially obtuse angle, and proceeds toward the hologram laser diode unit (22).

  When the linearly polarized P-wave second-wavelength laser light or linearly-polarized P-wavelength third-wavelength laser light returning through the optical path (L2a) passes through the DOE (21), the second-wavelength laser light or the third-wavelength laser light The direction of the second wavelength laser beam or the third wavelength laser beam is changed so that the optical path becomes an obtuse angle, and the second wavelength laser beam of the linearly polarized P wave or the third wavelength laser beam of the linearly polarized P wave is the optical path. Go through (L2h). The second wavelength laser beam or the third wavelength laser beam that has passed through the DOE (21) passes through the optical path (L2h), and is included in the metal cover (20c) constituting the LD (20). ).

By the PBS (25) provided with the special film (25c), the second wavelength laser beam or the third wavelength laser beam incident on the PBS (25) is internally reflected so as to have an obtuse angle, and passes through the PBS (25). Pass through and exit from PBS (25). The linearly polarized P-wave second-wavelength laser light or the linearly-polarized P-wavelength third-wavelength laser light internally reflected so as to form an obtuse angle in the PBS (25) returns the optical path (L2a), for example, a divergent lens (23). And reaches DOE (21). When the linearly polarized P-wave second-wavelength laser light or linearly-polarized P-wavelength third-wavelength laser light returning through the optical path (L2a) passes through the DOE (21), the second-wavelength laser light or the third-wavelength laser light The direction of the second wavelength laser beam or the third wavelength laser beam is changed so that the optical path becomes an obtuse angle, and the second wavelength laser beam of the linearly polarized P wave or the third wavelength laser beam of the linearly polarized P wave is the optical path. Go through (L2h). The second wavelength laser beam or the third wavelength laser beam that has passed through the DOE (21) passes through the optical path (L2h), and is included in the metal cover (20c) constituting the LD (20). ).

  Further, for example, the dual wavelength LD (20) that can emit the second wavelength laser beam and the third wavelength laser beam is a dual wavelength LD (20) that does not constitute the hologram laser diode unit (22). In some cases, the second PBS (25) internally reflects the S wave of the second wavelength laser beam and the S wave of the third wavelength laser beam in the PBS (25), and the P wave of the second wavelength laser beam and the first wave. It is configured to transmit the P wave of the three-wavelength laser light substantially straight. In this case, the coating (25c) in the PBS (25) internally reflects the S wave of the second wavelength laser beam and the S wave of the third wavelength laser beam, and the P wave of the second wavelength laser beam and the third wavelength laser. The light P wave is transmitted substantially straight. The coating (25c) in the PBS (25) transmits the first wavelength laser beam regardless of the P wave or S wave. The second wavelength laser light on the return path and the third wavelength laser light on the return path that are emitted from the PBS (40) after passing through the PBS (40) substantially straight and then return on the optical path (L2c) are both the second PBS (25 ) Passes substantially straight through and travels toward the sensor lens (80).

  By the PBS (25) provided with the special coating (25c), the linearly polarized P-wave second wavelength laser light or the linearly polarized P-wavelength third laser light incident on the PBS (25) travels substantially linearly and moves to the PBS. (25) Passes through and exits from PBS (25). The linearly polarized P-wave second wavelength laser light or the linearly polarized P-wavelength third laser light transmitted substantially straight through the PBS (25) reaches the sensor lens (80) through the optical path (L2b). Astigmatism occurs in the second wavelength laser beam or the third wavelength laser beam when the second wavelength laser beam of the linearly polarized P wave or the third wavelength laser beam of the linearly polarized P wave passes through the sensor lens (80). . The second wavelength laser beam or the third wavelength laser beam transmitted through the sensor lens (80) reaches the PDIC (90) through the optical path (L2b).

  The OPU 1 can be mounted on an optical disk device of a PC that is easy to carry, such as a notebook PC or laptop PC, for example, with a thickness of about 10 mm or less, specifically, a thickness of about 7.3 mm or less. Is formed. The thickness of the OPU 1 in this specification is, for example, the maximum thickness of the OPU 1 along the focus direction Df.

  By adopting the above optical layout in OPU1, it is compatible with various optical disks 100, 200, 300 of different standards, and can be installed in an optical disk device of a PC that is easy to carry, such as a notebook PC or laptop PC, for example. A thin OPU 1 having a thickness of about 10 mm or less, specifically, a thickness of about 7.3 mm or less is configured. Although it depends on the design / specifications of the optical disk device and OPU1 that are compatible with PCs that are easy to carry, such as notebook PCs or laptop PCs, it is made thinner due to the minimum size of the various parts that make up OPU1. It is assumed that the OPU 1 having a thickness of, for example, about 2 mm or more, specifically, a thickness of about 3 mm or more / over is necessary.

  The OPU 1 is shipped, for example, to an optical disk device assembly manufacturer or the like, and the optical disk device assembly manufacturer or the like constitutes one optical disk device including only one OPU 1.

When the OPU 1 is installed in the optical disc apparatus, reading of data from the various optical discs 100, 200, 300 and writing of data to the various optical discs 100, 200, 300 are performed by one optical disc apparatus provided with only one OPU 1. It becomes possible to execute. Various optical discs 100, 200, and 300 are installed in the optical disc device, and for example, data of the various optical discs 100, 200, and 300 are read out, or data is written into the various optical discs 100, 200, and 300, for example. Accordingly, it is possible to provide an optical disc apparatus that can handle various optical discs 100, 200, and 300.

  The OPU 1 is, for example, a read-only optical disc such as “CD-ROM”, “DVD-ROM”, “HD DVD-ROM”, “BD-ROM”, “CD-R”, “DVD-R”, Write-once optical disks such as “DVD + R”, “HD DVD-R”, “BD-R”, “CD-RW”, “DVD-RW”, “DVD + RW”, “DVD-RAM”, “HD DVD-” RW "," HD DVD-RAM "," BD-RE "and the like are compatible with write / erase and rewritable optical disks.

  The optical disk device provided with the OPU 1 is, for example, a computer such as a notebook personal computer (not shown), a laptop personal computer (not shown), a desktop personal computer (not shown), or a CD. It can be installed in an audio device such as a player or an audio / video device (not shown) such as a DVD player. Further, the optical disc apparatus provided with the OPU 1 can be adapted to a plurality of media such as a CD-type optical disc, a DVD-type optical disc, and a Blu-ray Disc.

  The optical pickup device according to the present invention and the optical disc device including the same are not limited to those illustrated or described above.

  For example, in the optical path intersection (LX) of the OPU (1) shown in FIG. 1, the first optical path (L1) and the second optical path (L2) may intersect at an inclined angle.

  Further, for example, the P wave or S wave of the laser beam of the CD system or the like may be reversed. Further, the clockwise circularly polarized laser beam and the counterclockwise circularly polarized laser beam may be reversed.

  Further, for example, OPU (1) (FIG. 1) in which only data reproduction is performed without writing data to the second media 200 that is a CD-series medium 200 (FIG. 2B). May be omitted without being equipped with a divergent lens (23).

  Further, for example, the OPU (1) corresponds to a read-only optical disk such as “CD-ROM”, “DVD-ROM”, “HD DVD-ROM”, “BD-ROM”, “CD-R”, Write-once optical disks such as “DVD-R”, “DVD + R”, “HD DVD-R”, “BD-R”, “CD-RW”, “DVD-RW”, “DVD + RW”, “DVD-RAM” ”,“ HD DVD-RW ”,“ HD DVD-RAM ”,“ BD-RE ”, and other types of rewritable / rewritable optical discs may not be supported.

  Further, for example, the QWP (57) may not be interposed in the optical path (L1) and may be omitted.

  Further, for example, the LD (30) is installed at the position where the hologram laser diode unit 22 shown in FIG. 1 is installed, and instead, the hologram laser diode unit (22) is installed at the position where the LD 30 shown in FIG. ) May be equipped.

  Further, for example, the first OBL (60) and the second OBL (70) positioned substantially on the disk center side of the housing (7) constituting the OPU (1) are orthogonal to the disk radial direction (Dr). May be arranged along the tangential direction (Ds), which is a direction perpendicular to the focus direction (Df).

Further, for example, instead of the first OBL 60 for Blu-ray Disc shown in FIGS. 2A and 3A, for example, the optical axis direction Df of the first wavelength laser light irradiated on the first medium 100 A pair of OBLs (not shown) arranged along the line may be arranged in the OPU 1 as an OBL for a Blu-ray Disc so as to be overlapped. That is, instead of the first OBL 60 for Blu-ray Disc shown in FIGS. 2 (A) and 3 (A), for example, a pair of OBLs (not shown) arranged in series along the focus direction Df -It may be deployed in OPU (1) as an OBL for a ray disc.

  Further, for example, instead of the one LDD 9 (FIG. 1), a first LDD (not shown) corresponding to the first LD 10 and a second LDD (not shown) corresponding to the second LD 20 are shown. And a third LDD (not shown) corresponding to the third LD 30 may be individually installed in the OPU 1. Also, a second LDD (not shown) corresponding to the second LD 20 and a third LDD (not shown) corresponding to the third LD 30 may be configured as one LDD (not shown). Good.

  Further, for example, the optical path L1f between the reflective MR 58 for Blu-ray Disc (FIG. 2 (A), FIG. 3 (A)) and the first OBL 60 for Blu-ray Disc, or Blu-ray Disc In the first optical path L1 such as the optical path L1e between the reflective MR 58 (FIG. 1) and the first dichroic mirror 48 for Blu-ray Disc, the condensing spot S1 (FIG. 2A) 3), aberration correction for the spherical aberration and the like generated in FIG. 3A) and correction of either or both of vertical birefringence and in-plane birefringence of the laser light irradiated to the optical disc 100 are performed. A liquid crystal correction element (not shown) for Blu-ray Disc may be further provided.

  Next, a second embodiment of an optical pickup device according to the present invention and an optical disk device including the same will be described in detail with reference to FIGS.

  FIG. 4 is a schematic view showing a second embodiment of the optical pickup device according to the present invention and an optical disk device including the same.

  The focusing detection method of the condensing spot S1 (FIGS. 2A, 3A), S2 (FIG. 2B), and S3 (FIG. 3B) in the OPU 2 is the same as that of the first embodiment. Similar to OPU1 (FIG. 1), the detection method is based on the differential astigmatism method. The OPU 2 (FIG. 4) is an OPU 2 having an optical system based on a differential astigmatism method. Further, the tracking detection method of the condensing spots S1, S2, and S3 in the OPU 2 is a detection method based on the differential push-pull method or the phase difference method, similar to the OPU 1 (FIG. 1) of the first embodiment. (FIG. 4).

  Instead of the LCD 37 located in the optical path L1c between the first PBS 40 (FIG. 1) and the third PBS 35, as shown in FIG. 4, in the optical path L1cr between the first PBS 40 and the third PBS 35, for example, A half-wave plate (HWP) 38 capable of polarizing S-wave or P-wave first wavelength laser light into P-wave or S-wave first wavelength laser light is movably equipped.

  The OPU 1 of the first embodiment shown in FIG. 1 and the OPU 2 of the second embodiment shown in FIG. 4 are different in the above-described portions. However, in other parts, the OPU 1 (FIG. 1) of the first embodiment and the OPU 2 (FIG. 4) of the second embodiment are the same. For example, as shown in FIGS. 1 and 4, the housing 7 </ b> A is formed as, for example, a standardized housing 7 </ b> A that can be used in common with the OPU 1 and the OPU 2. For example, the FPC 8A is formed as, for example, a standardized FPC 8A that can be used in common with the OPU 1 and the OPU 2. In the OPU 2 of the second embodiment shown in FIG. 4, components that are substantially the same as the OPU 1 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted.

  First, the first wavelength laser beam emitted from the first LD 10 (FIG. 4) passes through the first OBL 60 and passes through the first medium 100 of the “Blu-ray Disc” standard (FIGS. 2A and 3). The optical path until the first wavelength laser beam irradiated and reflected by (A)) reaches the first PDIC 90A (FIG. 4) will be described.

  Note that the first wavelength laser light emitted from the first LD 10 travels straight through the third PBS 35 and travels to the optical path L1cr, and the first wavelength laser light travels through the optical path L1cr travels straight through the first PBS 40. Then, the first PBL 90A (FIG. 4) is transmitted through the first OBL 60 and irradiated onto the first medium 100 (FIGS. 2A and 3A) of the “Blu-ray Disc” standard and reflected. ) And the description of the optical path until the first wavelength laser beam reaches the first FMD 50 are the same as the description of the optical path in the first embodiment, and the detailed description thereof is omitted. did.

  The linearly polarized P-wavelength first wavelength laser beam emitted from the first LD 10 and transmitted through the first DOE 11 through the optical path L1a passes substantially straight through the PBS 35, passes through the optical path L1cr, and passes through the optical path L1cr. It passes through the vicinity of the HWP 38 without being incident on the HWP 38. Alternatively, the linearly polarized P-wavelength first-wavelength laser light emitted from the first LD 10 and transmitted through the first DOE 11 through the optical path L1a passes substantially straight through the PBS 35, passes through the optical path L1cr, and is polarized. The light is incident on the HWP 38 serving as the conversion member 38.

  Instead of the LCD 37 shown in FIG. 1, for example, an HWP 38 capable of polarizing S-wave or P-wavelength first laser light into P-wave or S-wavelength first laser light is used as the polarization direction changing members 37 and 38. It is used. The HWP 38 is detachably mounted in the optical path L1cr of the first half optical path L1i that constitutes the first optical path L1. More specifically, when the HWP 38 is positioned in the optical path L1cr of the first optical path L1i constituting the first optical path L1, the HWP 38 that polarizes the P-wavelength first laser beam into the S-wavelength first laser beam. , Equipped in OPU2.

  By using the HWP 38 as the polarization direction changing member 38, the S-wave or P-wave first wavelength laser light is freely polarized into the P-wave or S-wave first wavelength laser light. When the HWP 38 is not positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the polarization state of the first wavelength laser light is not changed, and the first wavelength laser light of P wave or S wave Passes through the optical path L1cr with the P-wave or S-wave first wavelength laser light.

  More specifically, for example, when the HWP 38 is not positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the P-wavelength first wavelength laser light passing through the optical path L1cr in the vicinity of the HWP 38 is It passes through the optical path L1cr with the P-wavelength first wavelength laser light. In this case, for example, the P-wavelength first-wavelength laser light travels substantially straight through the PBS 40 and reaches the first OBL 60 through the second half optical path L1ii constituting the first optical path L1. It is condensed on (FIG. 2 (A), FIG. 3 (A)).

  Next, the first wavelength laser beam emitted from the first LD 10 (FIG. 4) passes through the second OBL 70 and is irradiated onto the third medium 300 (FIG. 3B) of the “HD DVD” standard. The optical path until the reflected first reflected laser beam reaches the first PDIC 90A (FIG. 4) will be described.

Note that the first wavelength laser beam emitted from the first LD 10 travels straight through the third PBS 35 and proceeds to the optical path L1cr, and the first wavelength laser beam that has traveled the optical path L1cr is within the first PBS 40. The first PDIC 90 </ b> A (FIG. 4) is reflected while being reflected at a substantially right angle, is transmitted through the second OBL 70, and is irradiated and reflected on the third medium 300 (FIG. 3B) of the “HD DVD” standard. Explanation of the optical path in the process of returning to the first position, and the first wavelength laser beam
Since the explanation of the optical path up to is the same as the explanation of the optical path in the first embodiment, the detailed explanation is omitted.

  The linearly polarized P-wavelength first wavelength laser beam emitted from the first LD 10 and transmitted through the first DOE 11 through the optical path L1a passes substantially straight through the PBS 35, passes through the optical path L1cr, and passes through the optical path L1cr. 38 enters the HWP 38. For example, when the HWP 38 is positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the P-wavelength first wavelength laser light incident on the HWP 38 is polarized into the S-wavelength first wavelength laser light. And emitted from the HWP 38. In this case, the S-wavelength first-wavelength laser light traveling in the optical path L1cr is internally reflected substantially at a right angle by the PBS 40 and reaches the second OBL 70 through the second half optical path L2ii constituting the second optical path L2, and is transmitted by the second OBL 70. The light is condensed on a third optical disc 300 (FIG. 3B) different from the first optical disc 100 (FIGS. 2A and 3A) and the second optical disc 200 (FIG. 2B).

  The second wavelength laser beam emitted from the second LD 20 (FIG. 4) is transmitted through the second OBL 70 and irradiated to the CD standard second medium 200 (FIG. 2 (B)) and reflected and reflected. Since the optical path until the second laser beam having reached the second PDIC 20b in the metal cover 20c constituting the LD 20 (FIG. 4) is the same as the optical path description in the first embodiment, Detailed explanation was omitted.

  Next, the third wavelength laser light emitted from the third LD 30 passes through the second OBL 70 and is irradiated on the third medium 300 (FIG. 3B) of the DVD standard, and is reflected and reflected. The optical path until the third wavelength laser beam reaches the first PDIC 90A (FIG. 4) will be described.

  The third wavelength laser beam emitted from the third LD 30 is transmitted through the third PBS 35 while being reflected at substantially right angles and travels to the optical path L1cr, or the first wavelength laser beam travels along the optical path L1cr. Is transmitted while being reflected at a substantially right angle in the first PBS 40, transmitted through the second OBL 70, irradiated onto the DVD standard third medium 300 (FIG. 3B), and reflected to the first PBS 40. The optical path explanation in the process of returning to the PDIC 90A (FIG. 4) and the optical path explanation until the third wavelength laser beam reaches the second FMD 65 are the same as the optical path explanation in the first embodiment. The explanation was omitted.

  The linearly polarized S-wavelength third-wavelength laser beam emitted from the third LD 30 and transmitted through the third DOE 31 through the optical path L1b is transmitted while being reflected substantially at right angles in the PBS 35 and proceeds to the optical path L1cr. For example, when the HWP 38 is not positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the polarization state of the third wavelength laser light is not changed, and the third wavelength of the P wave or S wave The laser beam passes through the optical path L1cr as a P-wave or S-wave third-wavelength laser beam. More specifically, for example, when the HWP 38 is not positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the S-wavelength third-wavelength laser light passing through the optical path L1cr in the vicinity of the HWP 38 is It passes through the optical path L1cr with the S-wavelength third-wavelength laser light.

  In this case, the S-wavelength third-wavelength laser light traveling in the optical path L1cr is internally reflected substantially at a right angle by the PBS 40 and reaches the second OBL 70 through the second half optical path L2ii that constitutes the second optical path L2. The light is condensed on a third optical disc 300 (FIG. 3B) different from the first optical disc 100 (FIGS. 2A and 3A) and the second optical disc 200 (FIG. 2B).

  Next, a third embodiment of the optical pickup device according to the present invention and the optical disk device including the same will be described in detail with reference to FIGS. 2, 3, and 5.

  FIG. 5 is a schematic view showing a third embodiment of the optical pickup device and the optical disk device including the same according to the present invention.

  The focusing detection method of the condensing spot S1 (FIGS. 2A, 3A), S2 (FIG. 2B), and S3 (FIG. 3B) in the OPU 3 is based on, for example, the knife edge method. Detection method. The knife edge method in this specification is a method of detecting errors of the focused spots S1, S2, and S3 using, for example, a knife edge, a DOE 75 (FIG. 5) having a diffraction grating function, and the like. The OPU 3 is an OPU 3 having an optical system based on a knife edge method. The tracking detection method of the condensing spots S1, S2, and S3 in the OPU 3 is a detection method based on the differential push-pull method or the phase difference method, similar to the OPU 1 (FIG. 1) of the first embodiment. The

  Instead of the first PDIC 90A located at the end of the optical path L2i in FIG. 1 and corresponding to the focusing detection method based on the differential astigmatism method, a first detection corresponding to the focusing detection method based on the knife edge method as shown in FIG. PDIC90B is equipped. Further, instead of the anamorphic lens 80A located in the optical path L2b in FIG. 1, a power lens 80B is provided in the optical path L2bs as shown in FIG. For example, a power lens 80B is used as the sensor lens 80B of the OPU 3 in the third embodiment. The optical path L2bs between the second PBS 25 and the sensor lens 80B is equipped with a DOE 75 for "Blu-ray Disc", "HD DVD", "DVD", or "CD". . The return path DOE 75 is a DOE having a knife edge formed by a plurality of divided hologram elements such as a four-divided hologram element. The OPU 3 includes a return path DOE 75 in which a knife edge is formed by a quadrant hologram element.

  The OPU 1 of the first embodiment shown in FIG. 1 is different from the OPU 3 of the third embodiment shown in FIG. However, in other parts, the OPU 1 (FIG. 1) of the first embodiment and the OPU 3 (FIG. 5) of the third embodiment are the same. For example, as shown in FIGS. 1 and 5, the housing 7 </ b> A is formed as, for example, a standardized housing 7 </ b> A that can be used in common with the OPU 1 and the OPU 3. For example, the FPC 8A is formed as, for example, a standardized FPC 8A that can be used in common with the OPU 1 and the OPU 3. In the OPU 3 of the third embodiment shown in FIG. 5, components that are substantially the same as the OPU 1 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted.

  First, the first wavelength laser beam emitted from the first LD 10 (FIG. 5) passes through the first OBL 60 and passes through the first medium 100 of the “Blu-ray Disc” standard (FIGS. 2A and 3). An optical path until the first wavelength laser beam irradiated and reflected by (A)) reaches the first PDIC 90B (FIG. 5) will be described. The first wavelength laser beam emitted from the first LD 10 passes through the first OBL 60 and is the first medium 100 of “Blu-ray Disc” standard (FIGS. 2A and 3A). The optical path in the process of being irradiated and reflected and returned to the second PBS 25 (FIG. 5) and the optical path until the first wavelength laser beam reaches the first FMD 50 are described. Since it is the same as the description, the detailed description is omitted.

The first optical path L1 passes through the optical path L1d, passes through the first PBS 40 while reflecting at a substantially right angle, passes through the optical path L2c of the second optical path L2, and is located at the branch point of the optical path L2a, the optical path L2bs, and the optical path L2c. The first wavelength laser beam of the linearly polarized S wave in the return path that has reached the second PBS 25 travels substantially straight through the second PBS 25, passes through the optical path L2bs, and reaches the return path DOE 75. Return D
The first-wavelength laser light in the return path that has passed through the OE 75 passes through the sensor lens 80B through the optical path L2bs. The first-path laser beam in the return path that has passed through the sensor lens 80B passes through the optical path L2bs and is applied to the first PDIC 90B.

  Next, the first wavelength laser beam emitted from the first LD 10 passes through the second OBL 70 and is irradiated and reflected on the third medium 300 (FIG. 3B) of the “HD DVD” standard. The optical path until the reflected first wavelength laser light reaches the first PDIC 90B (FIG. 5) will be described. The first wavelength laser light emitted from the first LD 10 is transmitted through the second OBL 70 and irradiated and reflected on the third medium 300 (FIG. 3B) of the “HD DVD” standard. The optical path explanation in the process of returning to the second PBS 25 (FIG. 5) and the optical path explanation until the first wavelength laser beam reaches the second FMD 65 are the same as the optical path explanation in the first embodiment. The detailed explanation was omitted.

  The first-wavelength laser light of the linearly polarized P wave in the return path that has passed through the optical path L2d of the second optical path L2 and passed substantially straight through the first PBS 40 and reached the second PBS 25 through the optical path L2c of the second optical path L2, It travels substantially straight through the second PBS 25, passes through the optical path L2bs, and reaches the return path DOE 75. The first wavelength laser beam in the return path that has passed through the return path DOE 75 passes through the optical path L2bs, passes through the sensor lens 80B, and is applied to the first PDIC 90B.

  The second wavelength laser light emitted from the second LD 20 passes through the second OBL 70 and is irradiated to the CD standard second medium 200 (FIG. 2B), reflected, and reflected. Since the optical path until the wavelength laser beam reaches the second PDIC 20b in the metal cover 20c constituting the LD 20 (FIG. 5) is the same as the optical path description in the first embodiment, a detailed description thereof will be given. Omitted.

  Next, the third wavelength laser light emitted from the third LD 30 passes through the second OBL 70 and is irradiated on the third medium 300 (FIG. 3B) of the DVD standard, and is reflected and reflected. The optical path until the third wavelength laser beam reaches the first PDIC 90B (FIG. 5) will be described.

  The third wavelength laser light emitted from the third LD 30 passes through the second OBL 70 and is irradiated on and reflected by the DVD standard third medium 300 (FIG. 3B). The optical path explanation in the process of returning to the PBS 25 (FIG. 5) and the optical path explanation until the third wavelength laser beam reaches the second FMD 65 are the same as the optical path explanation in the first embodiment. The explanation was omitted.

  The third-wavelength laser light of the linearly polarized P wave in the return path that has passed through the optical path L2d of the second optical path L2 and transmitted substantially straight through the first PBS 40 and reached the second PBS 25 through the optical path L2c of the second optical path L2, It travels substantially straight through the second PBS 25, passes through the optical path L2bs, and reaches the return path DOE 75. The laser beam of the third wavelength in the return path that has passed through the return path DOE 75 passes through the optical path L2bs, passes through the sensor lens 80B, and is applied to the first PDIC 90B.

  Next, a fourth embodiment of the optical pickup device and the optical disk device including the same according to the present invention will be described in detail with reference to FIG. 2, FIG. 3, and FIG.

  FIG. 6 is a schematic view showing a fourth embodiment of the optical pickup device and the optical disk device including the same according to the present invention.

The condensing spot S1 (FIG. 2 (A), FIG. 3 (A)), S2 (FIG. 2 (B) in this OPU4
)), S3 (FIG. 3B), the focusing detection method is, for example, a detection method based on the knife edge method, as in the OPU 3 (FIG. 5) of the third embodiment. For example, errors of the focused spots S1, S2, and S3 are detected using a knife edge, a DOE 75 (FIG. 6) having a diffraction grating function, and the like. The OPU 4 is an OPU 4 provided with an optical system based on a knife edge method. The tracking detection method of the condensing spots S1, S2 and S3 in the OPU 4 is the differential push-pull method, similar to the OPU 1 (FIG. 1) of the first embodiment and the OPU 3 (FIG. 5) of the third embodiment. Or, it is a detection method based on the phase difference method.

  Instead of the LCD 37 located in the optical path L1c between the first PBS 40 (FIG. 1) and the third PBS 35, as shown in FIG. 6, in the optical path L1cr between the first PBS 40 and the third PBS 35, for example, A half-wave plate (HWP) 38 capable of polarizing S-wave or P-wave first wavelength laser light into P-wave or S-wave first wavelength laser light is movably equipped.

  Further, instead of the first PDIC 90A corresponding to the focusing detection method based on the differential astigmatism method located at the end of the optical path L2i in FIG. 1, it corresponds to the focusing detection method based on the knife edge method as shown in FIG. The first PDIC 90B is equipped. Further, instead of the anamorphic lens 80A located in the optical path L2b in FIG. 1, a power lens 80B is provided in the optical path L2bs as shown in FIG. For example, a power lens 80B is used as the sensor lens 80B of the OPU 4 in the fourth embodiment. The optical path L2bs between the second PBS 25 and the sensor lens 80B is equipped with a DOE 75 for "Blu-ray Disc", "HD DVD", "DVD", or "CD". . The return path DOE 75 is a DOE having a knife edge formed by a plurality of divided hologram elements such as a four-divided hologram element. The OPU 4 includes a return path DOE 75 in which a knife edge is formed by a quadrant hologram element.

  The OPU 1 of the first embodiment shown in FIG. 1 and the OPU 4 of the fourth embodiment shown in FIG. However, in other parts, the OPU 1 (FIG. 1) of the first embodiment and the OPU 4 (FIG. 6) of the fourth embodiment are the same. For example, as shown in FIGS. 1 and 6, the housing 7 </ b> A is formed as, for example, a standardized housing 7 </ b> A that can be used in common with the OPU 1 and the OPU 4. For example, the FPC 8A is formed as, for example, a standardized FPC 8A that can be used in common with the OPU 1 and the OPU 4. In the OPU 4 of the fourth embodiment shown in FIG. 6, components that are substantially the same as the OPU 1 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted.

  First, the first wavelength laser beam emitted from the first LD 10 (FIG. 6) passes through the first OBL 60 and passes through the first medium 100 of the “Blu-ray Disc” standard (FIGS. 2A and 3). The optical path from when the first wavelength laser beam irradiated and reflected to (A)) reaches the first PDIC 90B (FIG. 6) will be described.

  Note that the first wavelength laser light emitted from the first LD 10 travels straight through the third PBS 35 and travels to the optical path L1cr, and the first wavelength laser light travels through the optical path L1cr travels straight through the first PBS 40. Then, the first medium 100 (FIGS. 2A and 3A) of the “Blu-ray Disc” standard is transmitted through the first OBL 60 and reflected and reflected by the second PBS 25 (FIG. 6). ) And the description of the optical path until the first wavelength laser beam reaches the first FMD 50 are the same as the description of the optical path in the first embodiment, and the detailed description thereof is omitted. did.

The linearly polarized P-wavelength first wavelength laser beam emitted from the first LD 10 and transmitted through the first DOE 11 through the optical path L1a passes substantially straight through the PBS 35, passes through the optical path L1cr, and passes through the optical path L1cr. It passes through the vicinity of the HWP 38 without being incident on the HWP 38. Alternatively, the linearly polarized P-wavelength first-wavelength laser light emitted from the first LD 10 and transmitted through the first DOE 11 through the optical path L1a passes substantially straight through the PBS 35, passes through the optical path L1cr, and is polarized. The light is incident on the HWP 38 serving as the conversion member 38.

  Instead of the LCD 37 shown in FIG. 1, for example, an HWP 38 capable of polarizing S-wave or P-wavelength first laser light into P-wave or S-wavelength first laser light is used as the polarization direction changing members 37 and 38. It is used. The HWP 38 is detachably mounted in the optical path L1cr of the first half optical path L1i that constitutes the first optical path L1. More specifically, when the HWP 38 is positioned in the optical path L1cr of the first optical path L1i constituting the first optical path L1, the HWP 38 that polarizes the P-wavelength first laser beam into the S-wavelength first laser beam. Equipped with OPU4.

  By using the HWP 38 as the polarization direction changing member 38, the S-wave or P-wave first wavelength laser light is freely polarized into the P-wave or S-wave first wavelength laser light. When the HWP 38 is not positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the polarization state of the first wavelength laser light is not changed, and the first wavelength laser light of P wave or S wave Passes through the optical path L1cr with the P-wave or S-wave first wavelength laser light.

  More specifically, for example, when the HWP 38 is not positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the P-wavelength first wavelength laser light passing through the optical path L1cr in the vicinity of the HWP 38 is It passes through the optical path L1cr with the P-wavelength first wavelength laser light. In this case, for example, the P-wavelength first-wavelength laser light travels substantially straight through the PBS 40 and reaches the first OBL 60 through the second half optical path L1ii constituting the first optical path L1. It is condensed on (FIG. 2 (A), FIG. 3 (A)).

  The first wavelength laser light reflected from the first optical disk 100 returns to the first PBS 40 through the latter half optical path L1ii constituting the first optical path L1 (FIG. 6). The first optical path L1 passes through the optical path L1d, passes through the first PBS 40 while reflecting at a substantially right angle, passes through the optical path L2c of the second optical path L2, and is located at the branch point of the optical path L2a, the optical path L2bs, and the optical path L2c. The first wavelength laser beam of the linearly polarized S wave in the return path that has reached the second PBS 25 travels substantially straight through the second PBS 25, passes through the optical path L2bs, and reaches the return path DOE 75. The first wavelength laser beam on the return path that has passed through the return path DOE 75 passes through the sensor lens 80B through the optical path L2bs. The first-path laser beam in the return path that has passed through the sensor lens 80B passes through the optical path L2bs and is applied to the first PDIC 90B.

  Next, the first wavelength laser beam emitted from the first LD 10 passes through the second OBL 70 and is irradiated and reflected on the third medium 300 (FIG. 3B) of the “HD DVD” standard. The optical path until the reflected first wavelength laser light reaches the first PDIC 90B (FIG. 6) will be described.

  Note that the first wavelength laser beam emitted from the first LD 10 travels straight through the third PBS 35 and proceeds to the optical path L1cr, and the first wavelength laser beam that has traveled the optical path L1cr is within the first PBS 40. Reflected and transmitted at substantially right angles, transmitted through the second OBL 70, irradiated onto the third medium 300 (FIG. 3B) of the “HD DVD” standard, and reflected and reflected to the second PBS 25 (FIG. 6). The explanation of the optical path in the process of returning to the point and the explanation of the optical path until the first wavelength laser beam reaches the second FMD 65 are the same as the explanation of the optical path in the first embodiment, and the detailed explanation is omitted. .

The linearly polarized P-wavelength first wavelength laser beam emitted from the first LD 10 and transmitted through the first DOE 11 through the optical path L1a passes substantially straight through the PBS 35, passes through the optical path L1cr, and passes through the optical path L1cr. 38 enters the HWP 38. For example, when the HWP 38 is positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the P-wavelength first wavelength laser light incident on the HWP 38 is polarized into the S-wavelength first wavelength laser light. And emitted from the HWP 38. In this case, the S-wavelength first-wavelength laser light traveling in the optical path L1cr is internally reflected substantially at a right angle by the PBS 40 and reaches the second OBL 70 through the second half optical path L2ii constituting the second optical path L2, and is transmitted by the second OBL 70. The light is condensed on a third optical disc 300 (FIG. 3B) different from the first optical disc 100 (FIGS. 2A and 3A) and the second optical disc 200 (FIG. 2B).

  The first wavelength laser light reflected from the third optical disk 300 returns to the first PBS 40 through the latter half optical path L2ii constituting the second optical path L2 (FIG. 6). The first-wavelength laser light of the linearly polarized P wave in the return path that has passed through the optical path L2d of the second optical path L2 and passed substantially straight through the first PBS 40 and reached the second PBS 25 through the optical path L2c of the second optical path L2, It travels substantially straight through the second PBS 25, passes through the optical path L2bs, and reaches the return path DOE 75. The first wavelength laser beam in the return path that has passed through the return path DOE 75 passes through the optical path L2bs, passes through the sensor lens 80B, and is applied to the first PDIC 90B.

  The second wavelength laser light emitted from the second LD 20 passes through the second OBL 70 and is irradiated to the CD standard second medium 200 (FIG. 2B), reflected, and reflected. Since the optical path until the wavelength laser beam reaches the second PDIC 20b in the metal cover 20c constituting the LD 20 (FIG. 6) is the same as the optical path description in the first embodiment, a detailed description thereof will be given. Omitted.

  Next, the third wavelength laser light emitted from the third LD 30 passes through the second OBL 70 and is irradiated on the third medium 300 (FIG. 3B) of the DVD standard, and is reflected and reflected. The optical path until the third wavelength laser beam reaches the first PDIC 90B (FIG. 6) will be described.

  The third wavelength laser beam emitted from the third LD 30 is transmitted through the third PBS 35 while being reflected at substantially right angles and travels to the optical path L1cr, or the first wavelength laser beam travels along the optical path L1cr. Is transmitted while being reflected at a substantially right angle in the first PBS 40, is transmitted through the second OBL 70, is irradiated on the third medium 300 (FIG. 3B) of the DVD standard, and is reflected and reflected. The optical path explanation in the process of returning to the PBS 25 (FIG. 6) and the optical path explanation until the third wavelength laser beam reaches the second FMD 65 are the same as the optical path explanation in the first embodiment. The explanation was omitted.

  The linearly polarized S-wavelength third-wavelength laser beam emitted from the third LD 30 and transmitted through the third DOE 31 through the optical path L1b is transmitted while being reflected substantially at right angles in the PBS 35 and proceeds to the optical path L1cr. For example, when the HWP 38 is not positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the polarization state of the third wavelength laser light is not changed, and the third wavelength of the P wave or S wave The laser beam passes through the optical path L1cr as a P-wave or S-wave third-wavelength laser beam. More specifically, for example, when the HWP 38 is not positioned in the optical path L1cr of the first half optical path L1i constituting the first optical path L1, the S-wavelength third-wavelength laser light passing through the optical path L1cr in the vicinity of the HWP 38 is It passes through the optical path L1cr with the S-wavelength third-wavelength laser light.

  In this case, the S-wavelength third-wavelength laser light traveling in the optical path L1cr is internally reflected substantially at a right angle by the PBS 40 and reaches the second OBL 70 through the second half optical path L2ii that constitutes the second optical path L2. The light is condensed on a third optical disc 300 (FIG. 3B) different from the first optical disc 100 (FIGS. 2A and 3A) and the second optical disc 200 (FIG. 2B).

  The third wavelength laser light reflected from the third optical disc 300 returns to the first PBS 40 through the latter half optical path L2ii constituting the second optical path L2 (FIG. 6). The third-wavelength laser light of the linearly polarized P wave in the return path that has passed through the optical path L2d of the second optical path L2 and transmitted substantially straight through the first PBS 40 and reached the second PBS 25 through the optical path L2c of the second optical path L2, It travels substantially straight through the second PBS 25, passes through the optical path L2bs, and reaches the return path DOE 75. The laser beam of the third wavelength in the return path that has passed through the return path DOE 75 passes through the optical path L2bs, passes through the sensor lens 80B, and is applied to the first PDIC 90B.

  Next, a fifth embodiment of the optical pickup device and the optical disk device including the same according to the present invention will be described in detail with reference to FIG. 2, FIG. 3, and FIG.

  FIG. 7 is a schematic diagram showing a fifth embodiment of the optical pickup device and the optical disk device including the same according to the present invention.

  The main difference between the OPU 1 (FIG. 1) of the first embodiment and the OPU 5 (FIG. 7) of the fifth embodiment will be described. In the OPU 1 of the first embodiment shown in FIG. In contrast to the LX equipped with the polarizing member 40, in the OPU 5 of the fifth embodiment shown in FIG. 7, the optical path intersection LX is omitted without being equipped with the polarizing member. Further, in the OPU 1 of the first embodiment shown in FIG. 1, a hologram laser diode unit 22 including a second LD 20 capable of emitting a second wavelength laser beam and a third laser beam capable of emitting a third wavelength laser beam. Each of the LDs 30 is provided, but in the OPU 5 of the fifth embodiment shown in FIG. 7, a dual wavelength light emitting element (dual wavelength LD) 20W capable of emitting the second wavelength laser beam and the third wavelength laser beam. Is equipped. The optical layout in the OPU 1 (FIG. 1) of the first embodiment is slightly different from the optical layout in the OPU 5 (FIG. 7) of the fifth embodiment.

  Further, other parts are also different between the OPU 1 (FIG. 1) of the first embodiment and the OPU 5 (FIG. 7) of the fifth embodiment. For example, the housing 7A of the OPU 1 shown in FIG. 1 and the housing 7B of the OPU 5 shown in FIG. 7 are formed in different shapes, although there are common parts such as bearings 7p, 7q, and 7r. Also, for example, the FPC 8A of the OPU 1 shown in FIG. 1 and the FPC 8B of the OPU 5 shown in FIG. In the OPU 5 of the fifth embodiment shown in FIG. 7, components that are substantially the same as the OPU 1 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted.

  The focusing detection method of the condensing spot S1 (FIG. 2 (A), FIG. 3 (A)), S2 (FIG. 2 (B)), S3 (FIG. 3 (B)) in this OPU 5 (FIG. 7) is differential. The detection method is based on the astigmatism method. This OPU 5 (FIG. 7) is an OPU 5 provided with an optical system based on a differential astigmatism method.

  Further, the tracking detection method of the condensing spot S1 (FIGS. 2A, 3A), S2 (FIG. 2B), S3 (FIG. 3B) in the OPU 5 is a differential push-pull. And a detection method based on the phase difference method. For example, tracking detection is performed based on the phase difference signal detected by the quadrant PDIC 91A, 92A (FIG. 7).

For example, a laser beam having an output value of 0.2 to 500 mW, specifically 3 to 300 mW, is emitted from each LD 10 and 20 W. For example, when the laser beam has an output value of less than 0.2 mW, the amount of the laser beam reflected after being irradiated on each of the optical discs 100, 200, and 300 (FIGS. 2 and 3) is insufficient. When reproducing each data of each optical disc 100, 200, 300, a laser beam with an output value of several to several tens mW, for example, about 3 to 10 mW is sufficient. When writing each data etc. to each optical disk 100, 200, 300, the laser beam of the output value of several dozen-several hundred mW is required. For example, when writing each data etc. to each optical disk 100, 200, 300 at high speed, a laser beam with a high output value of 300 mW or 500 mW may be required.

  First, the optical path of the laser emitted from the first LD 10 (FIG. 7) will be described. A current flows from the LDD 9 to the first LD 10, and a laser beam having the first wavelength is output from the first LD 10. The state in which the laser beam of the first wavelength is output from the first LD 10 will be described in detail. An electric current flows from the LDD 9 to the LD 10 for “Blu-ray Disc”, and the “Blu-ray Disc” LD 10 outputs “Blu”. -ray Disc "-type laser light with a wavelength corresponding to the disc is output. The first LD 10 is a “Blu-ray Disc” laser diode capable of emitting blue-violet laser light having a wavelength of about 350 to 450 nm and a reference wavelength of about 405 nm, for example.

  The LDD 9 includes a laser driving circuit that drives the first LD 10 to emit laser light having the first wavelength from the first LD 10. The LDD 9 includes a laser driving circuit that drives the second LD 20W to emit laser light having the second wavelength from the second LD 20W. The LDD 9 includes a laser driving circuit that drives the second LD 20W and emits laser light having a third wavelength from the second LD 20W. The LDD 9 is, for example, a standardized LDD 9 (FIG. 7) that can be shared with the OPU 1 (FIG. 1) of the first embodiment. The second LD 20W is configured as a special LD capable of emitting laser beams of a plurality of types of wavelengths.

  The optical path until the laser light emitted from the first LD 10 is applied to the “Blu-ray Disc” standard optical disc 100 will be described. A current is supplied from the LDD 9 to the first LD 10, and the “Blu-ray Disc” standard optical disc 100 (FIGS. 2A and 3) is generated by blue-violet laser light having a wavelength of 350 to 450 nm emitted from the first LD 10. (A)), information is recorded, or information recorded on the “Blu-ray Disc” standard optical disc 100 is reproduced. The first LD 10 (FIG. 7) is configured as a special LD.

  Diffused light is emitted from the first LD 10. The first wavelength laser beam of the diffused light output from the first LD 10 passes through the optical path L1at and passes through the first DOE 11 for “Blu-ray Disc”. When the laser beam having the first wavelength passes through the first DOE 11, the laser beam having the first wavelength becomes a linearly polarized P wave.

  The linearly polarized P-wave first wavelength laser light transmitted through the first DOE 11 is incident on the first PBS 16 through the optical path L1at. The first PBS 16 is configured to reflect the P wave at a substantially right angle within the PBS 16 and transmit the S wave substantially straightly. The first PBS 16 includes a special film 16c that forms a dichroic filter. The PBSs 16 and 26 are also called, for example, a dichroic prism or a polarization beam splitter depending on the use site and the use method.

  The PBS 16 includes a first member 16a having a substantially triangular prism shape, a second member 16b having a substantially triangular prism shape fitted to the first member 16a, and a special film 16c between the first member 16a and the second member 16b. It is configured as a provision. The substantially triangular prism-shaped first member 16a and the substantially triangular prism-shaped second member 16b are combined to form a substantially cubic PBS 16 having a special film 16c. A special film 16 c is provided between the first member 16 a constituting the first PBS 16 and the second member 16 b constituting the first PBS 16. A special film 16 c is formed in the first PBS 16. In the first PBS 16, there is provided a special film 16c that reflects linearly polarized P-waves at substantially right angles and transmits linearly polarized S-waves while traveling substantially straight.

  As a result, the linearly polarized P-wave laser light incident on the first PBS 16 is reflected at a substantially right angle in the first PBS 16, passes through the first PBS 16, and is emitted from the first PBS 16. Further, the linearly polarized S-wave laser light incident on the first PBS 16 travels substantially straight, passes through the first PBS 16, and is emitted from the first PBS 16. Examples of the PBS 16 provided with a special film 16c therein include a PBS prism manufactured by Tamron Co., Ltd. The linearly polarized P-wavelength first-wavelength laser light transmitted through the first DOE 11 is reflected at a substantially right angle in the first PBS 16, passes through the first PBS 16, and is incident on the first QWP 17.

  The first wavelength laser beam reflected substantially perpendicularly inside the first PBS 16 having a substantially cubic shape reaches the first QWP 17 through the optical path L1ct. The linearly polarized P-wave first-wavelength laser light passing through the optical path L1ct and transmitted through the first QWP 17 becomes circularly polarized light. The linearly polarized P-wave first wavelength laser light becomes, for example, right-handed circularly polarized light in the first QWP 17.

  The first wavelength laser light that has passed through the optical path L1ct and passed through the first QWP 17 and turned into circularly polarized light in the clockwise direction is a first optical path L1T that is an optical path L1T for Blu-ray Disc, and a first optical path L1T. And travels straight through an optical path intersection LX where the second optical path L2T, which is the optical path L2T for CD and DVD, intersects the first CL41. The first wavelength laser beam that has passed through the first QWP 17 and turned into right-handed circularly polarized light passes through the optical path L1ct, goes straight through the optical path intersection LX, passes through the optical path L1dt, and enters the first CL41. . The diffused first-wavelength laser light that has passed through the first QWP 17 substantially straight and passes through the optical path L1dt passes through the first CL 41 for “Blu-ray Disc”.

  The first CL41 is fixed to a holding member 42t that holds the CL41. The holding member 42t is attached to a guide member 43 that enables the holding member 42t to which the first CL 41 is attached to move along the optical path L1dt extending in the optical axis direction of the first CL 41. The guide member 43 is attached to a pedestal 44 including a motor (not shown) that drives the guide member 43 and the like. The pedestal 44 is attached to the housing 7B. An expander unit 46 including a first CL 41, a holding member 42t, a guide member 43, and a pedestal 44 is configured in the housing 7B of the OPU 5.

  For example, a movable motor (not shown) is used, and the holding member 42t including the first CL 41 moves on the guide member 43 along the optical path L1dt extending in the optical axis direction of the first CL 41. The single wavelength laser beam is varied to a required size. For example, when data is recorded on a Blu-ray Disc standard optical disc 100 having a plurality of signal layers, or when data recorded on a Blu-ray Disc standard optical disc 100 having a plurality of signal layers is reproduced. The beam expander unit 46 having the first CL 41 is required. The right-turn circularly polarized first wavelength laser light transmitted through the first CL 41 of the beam expander unit 46 becomes parallel light, passes through the optical path L1dt, and reaches a polarizing mirror 48, a so-called dichroic mirror 48.

For example, approximately 92 to 98% of the right-handed circularly polarized first-wavelength laser light irradiated on the front side surface 48a of the first dichroic mirror 48 through the optical path L1dt is approximately triangular prism-shaped first dichroic mirror 48. The front side surface 48a is reflected so as to have an acute angle rather than a right angle, and travels along the optical path L1e toward the first reflective MR 58. Further, for example, approximately 2 to 8% of the first-wavelength circularly polarized first-wavelength laser light irradiated to the front side surface 48a of the first dichroic mirror 48 through the optical path L1dt is approximately triangular prism-shaped first dichroic. The back side surface 48b of the first dichroic mirror 48 having a substantially triangular prism shape is bent from the front side surface 48a of the mirror 48 so as to have an obtuse angle, is incident on the first dichroic mirror 48, is transmitted through the first dichroic mirror 48.
Is bent and emitted so as to have an obtuse angle, and travels toward the first FMD 50 along the optical path L1g.

  More specifically, approximately 93 to 97% of the right-turn circularly polarized first wavelength laser light irradiated to the front side surface 48a of the first dichroic mirror 48 through the optical path L1dt is approximately triangular prism-shaped first. The light is reflected by the front side surface 48a of the dichroic mirror 48 so as to be slightly sharper than a right angle, and travels along the optical path L1e toward the first reflective MR 58. In addition, approximately 3 to 7% of the right-turn circularly polarized first wavelength laser light irradiated to the front side surface 48a of the first dichroic mirror 48 through the optical path L1dt is approximately triangular prism-shaped first dichroic mirror 48. The obtuse angle is bent from the front side surface 48a of the first dichroic mirror 48, is incident on the first dichroic mirror 48, passes through the first dichroic mirror 48, and is obtuse from the rear side surface 48b of the substantially triangular prism-shaped first dichroic mirror 48. The light is then bent and emitted, and travels along the optical path L1g toward the first FMD 50.

  The dichroic mirror 48 includes a special film 48c that forms a dichroic filter. A dichroic film 48 c is formed on the front side surface 48 a of the first dichroic mirror 48.

  When the right-turn circularly polarized first wavelength laser light is applied to the special film 48c on the front side surface 48a of the first dichroic mirror 48, the right-turn circularly polarized first wavelength laser light in the first dichroic mirror 48 is applied. Is less than 92%, for example, when the transmission amount of the first-wavelength circularly polarized first-wavelength laser light through the first dichroic mirror 48 is more than 8%, for example, the optical disc 100 (FIG. 2 ( A) and FIG. 3 (A)) lack the light quantity necessary for irradiating the first wavelength laser beam.

  Specifically, when the first-wavelength circularly polarized first wavelength laser beam is applied to the special film 48c on the front side surface 48a of the first dichroic mirror 48 (FIG. 7), the right side of the first dichroic mirror 48 When the reflection amount of the first wavelength laser beam of the circularly circularly polarized light is less than 93%, that is, the transmission amount of the first wavelength laser beam of the rightward circularly polarized light by the first dichroic mirror 48 is more than 7%. In this case, the amount of light necessary for irradiating the optical disc 100 (FIGS. 2A and 3A) with the first wavelength laser beam is insufficient.

  When the right-turn circularly polarized first wavelength laser light is applied to the special film 48c on the front side surface 48a of the first dichroic mirror 48 (FIG. 7), When the amount of reflection of one-wavelength laser light is larger than 98%, for example, when the amount of transmission of the first-wavelength circularly polarized first-wavelength laser light through the first dichroic mirror 48 is smaller than 2%, for example. The amount of received light of the first wavelength laser beam required for the FMD 50 is insufficient.

  More specifically, when the right-turn circularly polarized first wavelength laser light is applied to the special film 48c on the front side surface 48a of the first dichroic mirror 48, the right-turn circularly polarized light in the first dichroic mirror 48 is applied. When the amount of reflection of the first wavelength laser beam is greater than 97%, that is, when the amount of transmission of the first wavelength laser beam of right-turn circularly polarized light in the first dichroic mirror 48 is less than 3%, The amount of received light of the first wavelength laser beam required for the FMD 50 is insufficient.

When the right-turn circularly polarized first wavelength laser light is applied to the special film 48c on the front side surface 48a of the first dichroic mirror 48, the right-turn circularly polarized first wavelength laser light in the first dichroic mirror 48 is applied. Is reflected, for example, when the transmission amount of the first-wavelength circularly polarized first-wavelength laser light through the first dichroic mirror 48 is, for example, 5%, the optical disc 100 (FIG. 2 ( A sufficient laser beam is irradiated to A) and FIG. 3A, and an appropriate laser beam required for the first FMD 50 (FIG. 7) is irradiated. Therefore, it is preferable that the OPU 5 is equipped with the first dichroic mirror 48 having such characteristics.

  The dichroic film 48c of the dichroic mirror 48 reflects most of the right-turn circularly polarized “Blu-ray Disc” laser light (first wavelength laser light) having a wavelength of about 350 to 450 nm. When the first wavelength laser beam having a wavelength of 350 to 450 nm of right-handed circularly polarized light is applied to the first dichroic mirror 48, the first dichroic mirror 48 has a first wavelength laser having a wavelength of most 350 to 450 nm. It is formed to reflect light and transmit a part of the first wavelength laser light having a wavelength of 350 to 450 nm.

  The light enters the first dichroic mirror 48 from the front side surface 48 a of the substantially triangular prism-shaped first dichroic mirror 48, passes through the first dichroic mirror 48, and exits from the back side surface 48 b of the first triangular dichroic mirror 48. The part of the first-wavelength laser light thus made passes through the optical path L1g and reaches the first FMD 50. The FMD 50 monitors the laser light output from the LD 10 and applies feedback for controlling the LD 10.

  Most of the first-wavelength laser light reflected from the front side surface 48a of the substantially triangular prism-shaped first dichroic mirror 48 so as to have a slightly acute angle rather than a right angle passes through the optical path L1e and reaches the first reflective MR 58.

  The first wavelength laser light passing through the optical path L1e is applied to the first reflective MR 58 for reflecting the first wavelength light located on the upper side of the housing base wall reference portion 7h (FIGS. 2A and 3A). . The first reflective MR 58 is provided with a coating 58a that substantially totally reflects the laser light. Therefore, the laser beam applied to the reflective MR 58 is substantially totally reflected.

  The first-wavelength laser light passing through the optical path L1e (FIG. 7) reflects the reflective MR58 (FIGS. 2A and 3A) for “Blu-ray Disc” at a substantially right angle, and passes through the optical path L1f. Go through the first OBL60. The first-wavelength circularly polarized first-wavelength laser light that is parallel light becomes convergent light by the first OBL 60 having a numerical aperture of about 0.85, and is irradiated onto the signal unit 150 of the “Blu-ray Disc” standard optical disc 100. Is done.

  When the focus servo of the first OBL 60 mounted on the lens holder (not shown) is performed on the optical disc 100, the lens holder including the first OBL 60 is moved along the focus direction Df. Further, when tracking servo of the first OBL 60 mounted on a lens holder (not shown) is performed on the optical disc 100, the lens holder including the first OBL 60 is moved along the tracking direction Dr. Further, when tilt control of the first OBL 60 mounted on the lens holder is performed with respect to the optical disc 100, the lens holder including the first OBL 60 is swung along the tilt direction.

The lens holder equipped with the first OBL 60 is driven using a plurality of wires (not shown). More specifically, the lens holder is supported by an even number of suspension wires (not shown) such as four or six, and the even number of suspension wires, for example, the focus direction Df, tracking direction Dr, tilt It is driven substantially along any one direction or all directions among the directions. Further, a second OBL 70 is mounted on a lens holder (not shown) adjacent to the first OBL 60 (FIG. 7). With respect to the first OBL 60 positioned substantially on the center side of the disk of the housing 7B constituting the OPU 5, the second OBL 70 is arranged in parallel outside the first OBL 60 substantially along the disk radial direction Dr. Further, the optical axis LA1 of the first OBL 60 and the optical axis LA2 of the second OBL 70 are located on a virtual line substantially extending along the disk radial direction Dr so-called tracking direction Dr extending from the center of the disk toward the outer periphery of the disk. To do.

  The first wavelength laser light of the diffused light emitted from the first LD 10 is converted into a linearly polarized P wave by the first DOE 11 in the optical path L1at, and is circularly polarized clockwise from the linearly polarized P wave by the first QWP 17 in the optical path L1ct. Then, the first CL41 of the optical path L1dt is changed from the diffused light to the parallel light, and the first OBL 60 of the optical path L1f (FIG. 2 (A), FIG. 3 (A)) becomes the convergent light, and “Blu-ray Disc” The light is condensed on the signal unit 150 of the standard optical disc 100. The laser beam of the first wavelength follows the forward path in this way and is focused on the “Blu-ray Disc” standard optical disc 100 as the first medium 100.

  Next, the return path of the first wavelength laser beam reflected on the “Blu-ray Disc” standard optical disc 100 will be described. When the first wavelength laser light is reflected by the signal unit 150 of the “Blu-ray Disc” standard optical disc 100, the clockwise circularly polarized first wavelength laser light becomes counterclockwise circularly polarized light. The left-turn circularly polarized first-wavelength laser light becomes diffused light, returns through the optical path L1f, and reaches the first OBL 60. The left-handed circularly polarized first wavelength laser light that is diffused light is converted into parallel light by the first OBL 60. The left-turn circularly polarized first wavelength laser light that passes through the first OBL 60 and returns to the optical path L1f reaches the first reflective MR 58.

  The left-turn circularly polarized first wavelength laser light reflected by the first reflective MR 58 returns to the first dichroic mirror 48 through the optical path L1e (FIG. 7).

  The left-turn circularly polarized first wavelength laser light reflected by the front side surface 48a of the first dichroic mirror 48 returns to the first CL 41 through the optical path L1dt. When the first wavelength laser light returns through the optical path L1dt and passes through the first CL 41, the left-handed circularly polarized first wavelength laser light of the parallel light is Become. The left-turn circularly polarized first wavelength laser light transmitted through the first CL 41 passes through the optical path L1dt, goes straight through the optical path intersection LX, passes through the optical path L1ct, and is incident on the first QWP 17.

  When the first wavelength laser light returns through the optical path L1ct and passes through the first QWP 17, the left-turn circularly polarized first wavelength laser light becomes a linearly polarized S wave. The left-handed circularly polarized first wavelength laser light that has returned through the optical path L1dt and passed through the optical path intersection LX passes through the first QWP 17 through the optical path L1ct, and at that time becomes a linearly polarized S wave and reaches the PBS 16.

  In the PBS 16, a special film 16c that reflects the linearly polarized P wave at a substantially right angle and transmits the linearly polarized S wave in a substantially straight line is provided. It passes through almost straight. The linearly polarized S-wavelength first-wavelength laser light transmitted substantially straight through the PBS 16 reaches the first sensor lens 81A through the optical path L1bt.

  Astigmatism is generated in the first wavelength laser light when the linearly polarized S-wave first wavelength laser light passes through the first sensor lens 81A. The first sensor lens 81A generates astigmatism of the first wavelength laser beam.

  The first wavelength laser light that has passed through the first sensor lens 81A passes through the optical path L1bt and reaches the first PDIC 91A. The first PDIC 91A receives laser light reflected from the optical disc 100 (FIGS. 2A and 3A), converts the signal into an electrical signal, and detects information recorded on the optical disc 100. It is said that. The first PDIC 91A (FIG. 7) receives the laser beam reflected from the optical disc 100 (FIGS. 2A and 3A), converts the signal into an electrical signal, and converts the signal into an OPU 5 (FIG. 7). ) For operating a servo mechanism of an unillustrated lens holder with an OBL.

  The diffused first wavelength laser light reflected by the signal unit 150 of the “Blu-ray Disc” standard optical disc 100 (FIGS. 2A and 3A) is transmitted by the signal unit 150 of the optical disc 100. When reflected, it turns from right-handed circularly polarized light to left-handed circularly polarized light, becomes parallel light by the first OBL 60 in the optical path L1f, and is changed from parallel light to convergent light by the first CL41 in the optical path L1dt (FIG. 7), The first QWP 17 on the optical path L1ct changes the circularly polarized light from the left turn into a linearly polarized S wave, and the first PBS 16 positioned at the branch point between the optical path L1at, the optical path L1bt, and the optical path L1ct is substantially straight and positioned at the end of the optical path L1bt. The first PDIC 91A is irradiated. The first-wavelength laser light reflected from the “Blu-ray Disc” standard optical disc 100 (FIGS. 2A and 3A) follows the return path in this way, and passes through the first PDIC 91A (FIG. 7). Irradiated.

  Next, the optical path until the laser light emitted from the second LD 20W (FIG. 7) is irradiated onto the CD standard optical disc 200 (FIG. 2B) will be described. Current is supplied from the LDD 9 to the second LD 20W, and information is recorded on, for example, the CD standard optical disc 200 (FIG. 2B) by infrared laser light having a wavelength of 765 to 830 nm emitted from the second LD 20W. Or the information recorded on the CD standard optical disc 200 is reproduced. Also, current is supplied from the LDD 9 (FIG. 7) to the second LD 20W, and information is transmitted to the DVD standard optical disc 300 (FIG. 3B) by the red laser light having a wavelength of 630 to 685 nm emitted from the second LD 20W. Are recorded, and information recorded on the DVD standard optical disc 300 is reproduced. The second LD 20W (FIG. 7) can emit an infrared laser beam having a wavelength of about 765 to 830 nm and a reference wavelength of about 780 nm, for example, and has a wavelength of about 630 to 685 nm and a reference wavelength. This is a two-wavelength laser diode that can emit red laser light of approximately 635 nm or 650 nm. The second LD 20W is a special semiconductor laser diode.

  Diffused light is emitted from the second LD 20W (FIG. 7). The diffused second wavelength laser light output from the second LD 20W passes through the optical path L2at and the second DOE 24 for CD and DVD. When the second wavelength laser beam passes through the second DOE 24, the second wavelength laser beam becomes a linearly polarized S wave. The linearly polarized S-wave second-wavelength laser light transmitted through the second DOE 24 is incident on the second PBS 26 through the optical path L2at.

  The PBS 26 includes a first member 26a having a substantially triangular prism shape, a second member 26b having a substantially triangular prism shape fitted to the first member 26a, and a special film 26c between the first member 26a and the second member 26b. It is configured as a provision. The substantially triangular prism-shaped first member 26a and the substantially triangular prism-shaped second member 26b are combined to form a substantially cubic PBS 26 having a special film 26c. A special film 26 c is provided between the first member 26 a constituting the second PBS 26 and the second member 26 b constituting the second PBS 26. A special film 26 c is formed in the second PBS 26. In the second PBS 26, there is provided a special film 26c that reflects the linearly polarized S wave at a substantially right angle and transmits the linearly polarized P wave by traveling substantially straight.

As a result, the linearly polarized S-wave laser light incident on the second PBS 26 is reflected at a substantially right angle in the second PBS 26, passes through the second PBS 26, and is emitted from the second PBS 26. The linearly polarized P-wave laser light incident on the second PBS 26 travels substantially straight, passes through the second PBS 26, and is emitted from the second PBS 26. In the second PBS 26, the linearly polarized S wave of the second wavelength laser light or the linearly polarized S wave of the third wavelength laser light is reflected substantially at right angles, and the linearly polarized P wave of the second wavelength laser light or the third wavelength laser is reflected. Since the special coating 26c that transmits the linearly polarized P wave of light substantially straight is transmitted, the laser light of the linearly polarized S wave of the second wavelength light incident on the second PBS 26 is internally reflected at a substantially right angle. Then, the light passes through the PBS 26 and is emitted from the PBS 26. Examples of the PBS 26 having a special film 26c therein include a PBS prism manufactured by Tamron Corporation. The linearly polarized S-wavelength second-wavelength laser light transmitted through the second DOE 24 is internally reflected through the second PBS 26 at a substantially right angle, passes through the optical paths L2ct and L2dt, and reaches the second CL61.

  The second-wavelength laser light of the linearly polarized S wave emitted from the second PBS 26 passes through the optical path L2ct and is substantially orthogonal to the second optical path L2T and the optical path L2T for CD and DVD, and is orthogonal to the second optical path L2T. The light travels straight through the optical path intersection LX where the first optical path L1T, which is the optical path L1T for the -ray disc, intersects, and enters the second CL 61 through the optical path L2dt.

  The S-wavelength second-wavelength laser light passes through the optical path L2ct and travels straight through the optical path intersection LX. The S-wavelength second-wavelength laser light traveling straight through the optical path intersection LX passes through the second CL 61 through the optical path L2dt. The S-wavelength second-wavelength laser light transmitted through the second CL 61 becomes substantially parallel light, passes through the optical path L2dt, and reaches the second QWP 62. The second wavelength laser light transmitted through the second CL 61 enters the second QWP 62. The linearly polarized S wave second wavelength laser light transmitted through the second QWP 62 becomes circularly polarized light. The second-wavelength laser light of the linearly polarized S wave becomes, for example, left-handed circularly polarized light in the second QWP 62. The second-wavelength laser light that has turned counterclockwise circularly polarized light reaches the second dichroic mirror 64.

  Through the optical path L2dt, the front side surface 64a of the second dichroic mirror 64 is irradiated with left-handed circularly polarized second wavelength laser light. For example, approximately 92 to 98% of the left-handed circularly polarized second-wavelength laser light irradiated on the front side surface 64a of the second dichroic mirror 64 through the optical path L2dt is substantially triangular prism-shaped second dichroic mirror 64. The light is reflected at a substantially right angle on the front side surface 64a and travels along the optical path L2e toward the second reflective MR68. Further, for example, approximately 2 to 8% of the left-circular circularly polarized second wavelength laser light irradiated to the front side surface 64a of the second dichroic mirror 64 through the optical path L2dt is a substantially triangular prism-shaped second dichroic mirror. The obtuse angle is bent from the front side surface 64a of the 64, is incident on the second dichroic mirror 64, is transmitted through the second dichroic mirror 64, and is obtuse from the rear side surface 64b of the substantially triangular prism-shaped second dichroic mirror 64. Then, the light is bent and emitted, and proceeds on the optical path L2gt toward the second FMD 65.

  More specifically, approximately 93 to 97% of the left-handed circularly polarized second-wavelength laser light irradiated on the front side surface 64a of the second dichroic mirror 64 through the optical path L2dt is approximately triangular prism-shaped second. The light is reflected at a substantially right angle by the front side surface 64a of the dichroic mirror 64 and travels along the optical path L2e toward the second reflective MR 68. In addition, approximately 3 to 7% of the left-handed circularly polarized second-wavelength laser light irradiated to the front side surface 64a of the second dichroic mirror 64 through the optical path L2dt is substantially triangular prism-shaped second dichroic mirror 64. It is bent from the front side surface 64a so as to have an obtuse angle, enters the second dichroic mirror 64, passes through the second dichroic mirror 64, and becomes an obtuse angle from the back side surface 64b of the substantially triangular prism-shaped second dichroic mirror 64. Is bent and emitted, and travels along the optical path L2gt toward the second FMD 65.

  Reflection of counterclockwise circularly polarized second wavelength laser light on the second dichroic mirror 64 when the counterclockwise circularly polarized second wavelength laser light is applied to the special film 64c on the back side surface 64b of the second dichroic mirror 64. If the amount is less than 92%, for example, that is, if the transmission amount of the second-wavelength laser light of left-handed circularly polarized light in the second dichroic mirror 64 is more than 8%, for example, the optical disc 200 (FIG. 2B) Insufficient light quantity to irradiate the second wavelength laser beam.

More specifically, when the second film of the left-handed circularly polarized light is applied to the special film 64c on the back side surface 64b of the second dichroic mirror 64 (FIG. 7), the second dichroic mirror 64 turns left. When the reflection amount of the circularly polarized second wavelength laser beam is less than 93%, that is, when the transmission amount of the left-turn circularly polarized second wavelength laser beam in the second dichroic mirror 64 is more than 7%, the optical disk The amount of light necessary for irradiating 200 (FIG. 2B) with the second wavelength laser light is insufficient.

  The second wavelength of the left-handed circularly polarized light in the second dichroic mirror 64 when the second-wavelength laser light of the left-handed circularly polarized light is applied to the special film 64c on the back side surface 64b of the second dichroic mirror 64 (FIG. 7). When the reflection amount of the laser light is larger than 98%, for example, when the transmission amount of the second wavelength laser light of the left-handed circularly polarized light in the second dichroic mirror 64 is smaller than 2%, for example, the second FMD 65 The required amount of received second-wavelength laser light is insufficient.

  More specifically, when the second-wavelength laser light having left-handed circular polarization is applied to the special film 64c on the back surface 64b of the second dichroic mirror 64, the second left-handed circularly-polarized light in the second dichroic mirror 64 is applied. When the reflection amount of the two-wavelength laser light is larger than 97%, that is, when the transmission amount of the left-turn circularly polarized second-wavelength laser light in the second dichroic mirror 64 is smaller than 3%, the second FMD 65 The required amount of received second-wavelength laser light is insufficient.

  Reflection of counterclockwise circularly polarized second wavelength laser light on the second dichroic mirror 64 when the counterclockwise circularly polarized second wavelength laser light is applied to the special film 64c on the back side surface 64b of the second dichroic mirror 64. When the amount is, for example, 95%, that is, when the transmission amount of the left-turn circularly polarized second-wavelength laser light through the second dichroic mirror 64 is, for example, 5%, the optical disc 200 (FIG. 2B) A sufficient amount of laser light is irradiated and an appropriate amount of laser light required for the second FMD 65 (FIG. 7) is irradiated. Therefore, it is preferable that the OPU 5 is equipped with the second dichroic mirror 64 having such characteristics.

  The dichroic film 64c of the dichroic mirror 64 reflects most of the left-handed circularly polarized CD laser light (second wavelength laser light) having a wavelength of about 765 to 830 nm. When the second wavelength laser beam having a wavelength of 765 to 830 nm of left-handed circularly polarized light is applied to the second dichroic mirror 64, the second dichroic mirror 64 has the second wavelength laser beam having a most wavelength of 765 to 830 nm. Is reflected, and a part of the second wavelength laser beam having a wavelength of 765 to 830 nm is transmitted.

  The obtuse angle from the back side surface 64b of the substantially triangular prism-shaped second dichroic mirror 64 through the second dichroic mirror 64 through the second dichroic mirror 64 through the front side surface 64a of the substantially triangular prism-shaped second dichroic mirror 64. A part of the second-wavelength laser light that is bent and emitted so as to pass through the optical path L2gt reaches the second FMD 65. The FMD 65 monitors the laser beam output from the two-wavelength LD 20W and applies feedback for controlling the two-wavelength LD 20W.

  The left-handed circularly polarized second-wavelength laser light reflected from the front side surface 64a of the second dichroic mirror 64 at a substantially right angle passes through the optical path L2e and is located above the housing base wall reference portion 7h (FIG. 2B). Applied to second reflective MR68. Since the second reflective MR 68 is provided with the coating 68a that substantially totally reflects the laser light, the laser light applied to the reflective MR 68 is substantially totally reflected.

The left-handed circularly polarized second-wavelength laser light reflected from the front side surface 64a of the second dichroic mirror 64 (FIG. 7) at a substantially right angle passes through the optical path L2e and passes through the reflective MR 68 (FIG. 2 (B)) at a right angle. The light is reflected at a slight acute angle, passes through the aperture limiting element 69 through the optical path L2fc. When a second wavelength laser beam having a wavelength of about 765 to 830 nm for CD passes through the aperture limiting element 69,
Phase correction of the second wavelength laser light is performed. The first side surface 69a of the aperture limiting element 69 is shielded by masking a part of the infrared laser beam for CD (second wavelength laser beam) having a wavelength of about 765 to 830 nm, and is used for a DVD having a wavelength of about 630 to 685 nm. Since the special film 69c that transmits the red laser beam (third wavelength laser beam) without masking is provided, when the second wavelength laser beam passes through the aperture limiting element 69, the second wavelength laser beam is In the masked state, the OBL 70 is entered and narrowed down by the OBL 70.

  As a result, the second wavelength laser light is narrowed down by the OBL 70 in the same state as being narrowed down by an OBL (not shown) having a numerical aperture of about 0.45. The actual numerical aperture of the OBL 70 is approximately 0.6 or 0.65. However, if the aperture limiting element 69 is provided in the optical path, the second wavelength laser light enters the OBL 70 in a masked state. Therefore, the second wavelength laser light is condensed on the signal unit 250 of the optical disk for CD 200 in the same state as being narrowed down using an OBL (not shown) having a numerical aperture of about 0.45. By providing the aperture limiting element 69 in the optical path, even if one OBL 70 having a numerical aperture of about 0.6 to 0.65 is used, the OBL 70 has a numerical aperture of about 0.37 to 0.95, for example. It functions substantially as a numerical aperture of about 0.45 to 0.65. The left-turn circularly polarized second wavelength laser light is applied by the special film 69c formed on the first side surface 69a of the aperture limiting element 69 when it enters the aperture limiting element 69 from the first side surface 69a of the aperture limiting element 69. Masked and emitted from the second side surface 69b of the aperture limiting element 69 in the masked state. As described above, the OPU 5 includes the aperture limiting element 69 that acts on the second wavelength laser light without acting on the third wavelength laser light.

  Depending on the design / specifications of the OPU 5, for example, a special film (69c) may be provided on the second side surface (69b) of the aperture limiting element (69). Further, in place of the opening limiting element 69 in which the special film 69c is formed on the first side surface 69a, for example, an opening limiting element (69) in which the special film (69c) is formed on the second side surface (69b) can be used. The

The special films 16c, 26c, 48c, 64c, and 69c such as the dichroic films 48c and 64c are formed on a desired surface based on, for example, a vacuum deposition method or a sputtering method. The special films 16c, 26c, 48c, 64c, and 69c such as the dichroic films 48c and 64c are selected from the group consisting of SiO ₂ , ZnO ₂ , Ta ₂ O ₅ , TiO _2, and Ti ₂ O _5, for example. It is configured as a layer containing at least one or more substances. More specifically, each of the dichroic films 48c and 64c is a thin layer containing at least one material selected from the group consisting of SiO ₂ , ZnO ₂ , Ta ₂ O ₅ , TiO ₂ and Ti ₂ O _5. Configured as

  The left-turn circularly polarized second-wavelength laser light transmitted through the aperture limiting element 69 passes through the second OBL 70. The left-handed circularly polarized second-wavelength laser light that is substantially parallel light becomes convergent light by the second OBL 70 and is applied to the signal portion 250 of the optical disk 200 of the CD standard.

  When the focus servo of the second OBL 70 mounted on the lens holder (not shown) is performed on the optical disc 200, the lens holder including the second OBL 70 is moved along the focus direction Df. Further, when the tracking servo of the second OBL 70 mounted on the lens holder (not shown) is performed on the optical disc 200, the lens holder including the second OBL 70 is moved along the tracking direction Dr. Further, when tilt control of the second OBL 70 mounted on the lens holder is performed on the optical disc 200, the lens holder including the second OBL 70 is swung along the tilt direction Dt.

The second-wavelength laser light of the diffused light emitted from the second LD 20W (FIG. 7) is converted into a linearly polarized S wave by the second DOE 24 in the optical path L2at, and the diffused light is made substantially parallel light by the second CL 61 in the optical path L2dt. The second QWP 62 in the optical path L2dt is converted to a left-turn circularly polarized light from the linearly polarized S wave, masked by the aperture limiting element 69 in the optical path L2fc (FIG. 2B), and converged by the second OBL 70, The light is focused on the signal section 250 of the CD standard optical disc 200. The laser beam of the second wavelength follows the forward path in this way, and is focused on the CD standard optical disc 200 as the second medium 200.

  Next, the return path of the second wavelength laser beam reflected from the CD standard optical disc 200 will be described. When the second wavelength laser light is reflected by the signal unit 250 of the CD standard optical disc 200, the left-handed circularly polarized second-wavelength laser light becomes right-handed circularly polarized light. The right-turn circularly polarized second-wavelength laser light becomes diffused light, returns through the optical path L2fc, and reaches the second OBL 70. The right-handed circularly polarized second-wavelength laser light that is diffused light becomes substantially parallel light by the second OBL 70. The right-turn circularly polarized second-wavelength laser light that passes through the second OBL 70 and returns to the optical path L2fc passes through the aperture limiting element 69 and reaches the second reflective MR 68.

  The right-turn circularly polarized second wavelength laser light reflected by the second reflective MR 68 returns to the second dichroic mirror 64 through the optical path L2e (FIG. 7).

  The right-turn circularly polarized second wavelength laser light reflected by the front side surface 64a of the second dichroic mirror 64 returns to the second QWP 62 through the optical path L2dt. When the second wavelength laser beam returns through the optical path L2dt and passes through the second QWP 62, the right-turn circularly polarized second wavelength laser beam becomes a linearly polarized P wave. The linearly polarized P-wave second-wavelength laser light transmitted through the second QWP 62 reaches the second CL 61. When the second wavelength laser beam returns through the optical path L2dt and passes through the second CL 61, the second wavelength laser beam of the substantially parallel linearly polarized P wave is the second wavelength laser beam of the linearly polarized P wave of the convergent light. It becomes. The linearly polarized P-wavelength second-wavelength laser light transmitted through the second CL 61 returns through the optical path L2dt, travels straight through the optical path intersection LX, returns through the optical path L2ct, and is incident on the second PBS 26.

  When the second wavelength laser beam returns through the optical path L2dt and passes through the second QWP 62, the right-turn circularly polarized second wavelength laser beam becomes a linearly polarized P wave. The linearly polarized P-wave second-wavelength laser light that has returned the optical path L2dt and passed through the optical path intersection LX reaches the PBS 26 through the optical path L2ct. In the PBS 26, the linearly polarized P wave of the second wavelength laser light or the linearly polarized P wave of the third wavelength laser light travels substantially straight, and the linearly polarized S wave of the second wavelength laser light or the linearly polarized light S of the third wavelength laser light. Since the special film 26c that reflects and transmits the wave at substantially right angles is provided, the linearly polarized P-wave second-wavelength laser light passes through the PBS 26 substantially straight.

  The linearly polarized P-wave second-wavelength laser light that has been transmitted substantially straight through the PBS 26 passes through the optical path L2bt and reaches the second sensor lens 82A. Astigmatism occurs in the second wavelength laser light when the second wavelength laser light of the linearly polarized P wave passes through the second sensor lens 82A. The second sensor lens 82A is configured to generate astigmatism of the second wavelength laser beam or the third wavelength laser beam.

  The second wavelength laser light transmitted through the second sensor lens 82A passes through the optical path L2bt and reaches the second PDIC 92A. The second PDIC 92A receives the laser beam reflected from the optical disc 200 (FIG. 2B), converts the signal into an electrical signal, and detects information recorded on the optical disc 200. . The second PDIC 92A (FIG. 7) receives the laser beam reflected from the optical disc 200 (FIG. 2B), converts the signal into an electrical signal, and configures the OPU 5 (FIG. 7). It is intended to operate the servo mechanism of the lens holder with OBL.

The diffused second wavelength laser light reflected by the signal portion 250 of the “CD” standard optical disc 200 (FIG. 2B) is left-turned when reflected by the signal portion 250 of the optical disc 200. From the polarized light, it becomes a right-handed circularly polarized light, becomes parallel light by the second OBL 70 in the optical path L2fc, and becomes a linearly polarized P wave from the right-handed circularly polarized light by the second QWP 62 of the optical path L2dt (FIG. 7), The parallel light is changed from the parallel light to the convergent light by the second CL 61, travels substantially straight through the second PBS 26 located at the branch point of the optical path L2at, the optical path L2bt, and the optical path L2ct, and irradiates the second PDIC 92A located at the end of the optical path L2bt. Is done. The second-wavelength laser light reflected from the “CD” standard optical disc 200 (FIG. 2B) follows the return path in this way and is irradiated to the second PDIC 92A (FIG. 7).

  Next, the optical path until the laser beam emitted from the second LD 20W (FIG. 7) is irradiated onto the DVD standard optical disc 300 (FIG. 3B) will be described. The second LD 20W is a two-wavelength laser diode capable of emitting a laser beam for CD and a laser beam for DVD.

  Diffused light is emitted from the second LD 20W (FIG. 7). The diffused third-wavelength laser light output from the second LD 20W passes through the optical path L2at and the second DOE 24 for CD and DVD. When the third wavelength laser beam passes through the second DOE 24, the third wavelength laser beam becomes a linearly polarized S wave.

  The linearly polarized S-wavelength third-wavelength laser light transmitted through the second DOE 24 is incident on the second PBS 26 through the optical path L2at. In the second PBS 26, the linearly polarized S wave of the second wavelength laser light or the linearly polarized S wave of the third wavelength laser light is reflected substantially at right angles, and the linearly polarized P wave of the second wavelength laser light or the third wavelength laser is reflected. Since the special coating 26c that transmits the linearly polarized P wave of light substantially straight is transmitted, the laser light of the linearly polarized S wave of the second wavelength light incident on the second PBS 26 is internally reflected at a substantially right angle. Then, the light passes through the PBS 26 and is emitted from the PBS 26. The linearly polarized S-wavelength third-wavelength laser light transmitted through the second DOE 24 passes through the second PBS 26 by being internally reflected at a substantially right angle, passes through the optical paths L2ct and L2dt, and reaches the second CL61.

  The linearly polarized S-wave third-wavelength laser light emitted from the second PBS 26 passes through the optical path L2ct and is substantially orthogonal to the second optical path L2T and the second optical path L2T. The light travels straight through the optical path intersection LX where the first optical path L1T, which is the optical path L1T for the -ray disc, intersects, and enters the second CL 61 through the optical path L2dt.

  The S-wavelength third-wavelength laser light passes through the optical path L2ct and travels straight through the optical path intersection LX. The S-wavelength third-wavelength laser beam that has traveled straight through the optical path intersection LX passes through the second CL 61 through the optical path L2dt. The S-wavelength third-wavelength laser light transmitted through the second CL 61 becomes substantially parallel light, passes through the optical path L2dt, and reaches the second QWP 62. The third wavelength laser light that has passed through the second CL 61 enters the second QWP 62. The linearly polarized S-wave third-wavelength laser light transmitted through the second QWP 62 becomes circularly polarized light. The third-wavelength laser light of linearly polarized S wave becomes, for example, left-handed circularly polarized light in the second QWP 62. The third-wavelength laser light that has turned counterclockwise circularly polarized light reaches the second dichroic mirror 64.

Through the optical path L2dt, the front side surface 64a of the second dichroic mirror 64 is irradiated with the left-turn circularly polarized third-wavelength laser light. For example, approximately 92 to 98% of the left-handed circularly polarized third-wavelength laser light irradiated to the front side surface 64a of the second dichroic mirror 64 through the optical path L2dt is substantially triangular prism-shaped second dichroic mirror 64. The light is reflected at a substantially right angle on the front side surface 64a and travels along the optical path L2e toward the second reflective MR68. Further, for example, approximately 2 to 8% of the left-turn circularly polarized third-wavelength laser light irradiated on the front side surface 64a of the second dichroic mirror 64 through the optical path L2dt is a substantially triangular prism-shaped second dichroic mirror. The back side surface 6 of the second dichroic mirror 64 having a substantially triangular prism shape is bent at an obtuse angle from the front side surface 64a of the 64, is incident on the second dichroic mirror 64, is transmitted through the second dichroic mirror 64.
4b is bent and emitted so as to have an obtuse angle, and travels toward the second FMD 65 along the optical path L2gt.

  More specifically, approximately 93 to 97% of the left-turn circularly polarized third-wavelength laser light irradiated on the front side surface 64a of the second dichroic mirror 64 through the optical path L2dt is approximately triangular prism-shaped second. The light is reflected at a substantially right angle by the front side surface 64a of the dichroic mirror 64 and travels along the optical path L2e toward the second reflective MR 68. Further, approximately 3 to 7% of the left-handed circularly polarized third-wavelength laser light irradiated to the front side surface 64a of the second dichroic mirror 64 through the optical path L2dt is substantially triangular prism-shaped second dichroic mirror 64. It is bent from the front side surface 64a so as to have an obtuse angle, enters the second dichroic mirror 64, passes through the second dichroic mirror 64, and becomes an obtuse angle from the back side surface 64b of the substantially triangular prism-shaped second dichroic mirror 64. Is bent and emitted, and travels along the optical path L2gt toward the second FMD 65.

  Reflection of counterclockwise circularly polarized third wavelength laser light on the second dichroic mirror 64 when the counterclockwise circularly polarized third wavelength laser light is applied to the special film 64c on the back side surface 64b of the second dichroic mirror 64. When the amount is smaller than 92%, for example, when the transmission amount of the left-turn circularly polarized third-wavelength laser light through the second dichroic mirror 64 is larger than 8%, for example, the optical disc 300 (FIG. 3B) Insufficient light quantity to irradiate the third wavelength laser beam.

  More specifically, when the special film 64c on the back side surface 64b of the second dichroic mirror 64 (FIG. 7) is irradiated with the counterclockwise circularly polarized third wavelength laser light, the second dichroic mirror 64 turns counterclockwise. When the reflection amount of the circularly polarized third-wavelength laser light is less than 93%, that is, when the transmission amount of the left-turn circularly-polarized third-wavelength laser light through the second dichroic mirror 64 is more than 7%, the optical disk The amount of light necessary for irradiating 300 (FIG. 3B) with the third wavelength laser light is insufficient.

  The third wavelength of left-handed circularly polarized light in the second dichroic mirror 64 is applied to the special film 64c on the back side surface 64b of the second dichroic mirror 64 (FIG. 7) when left-turned circularly-polarized third wavelength laser light is applied. When the reflection amount of the laser light is larger than 98%, for example, when the transmission amount of the left-turn circularly polarized third-wavelength laser light in the second dichroic mirror 64 is smaller than 2%, for example, the second FMD 65 The required amount of received third-wavelength laser light is insufficient.

  More specifically, when the third-wavelength laser light with left-handed circular polarization is applied to the special film 64c on the back side surface 64b of the second dichroic mirror 64, the second left-handed circularly-polarized light at the second dichroic mirror 64 is When the reflection amount of the three-wavelength laser light is larger than 97%, that is, when the transmission amount of the left-turn circularly polarized third-wavelength laser light in the second dichroic mirror 64 is smaller than 3%, the second FMD 65 The required amount of received third-wavelength laser light is insufficient.

  Reflection of counterclockwise circularly polarized third wavelength laser light on the second dichroic mirror 64 when the counterclockwise circularly polarized third wavelength laser light is applied to the special film 64c on the back side surface 64b of the second dichroic mirror 64. When the amount is, for example, 95%, that is, when the transmission amount of the left-turn circularly polarized third-wavelength laser light through the second dichroic mirror 64 is, for example, 5%, the optical disc 300 (FIG. 3B) A sufficient amount of laser light is irradiated and an appropriate amount of laser light required for the second FMD 65 (FIG. 7) is irradiated. Therefore, it is preferable that the OPU 5 is equipped with the second dichroic mirror 64 having such characteristics.

The dichroic film 64c of the dichroic mirror 64 reflects most of the counterclockwise circularly polarized DVD laser light (third wavelength laser light) having a wavelength of about 630 to 685 nm. When the third-wavelength laser light having a wavelength of 630 to 685 nm of left-handed circularly polarized light is applied to the second dichroic mirror 64, the second dichroic mirror 64 has the third-wavelength laser light having a majority of wavelengths of 630 to 685 nm. Is reflected, and a part of the third wavelength laser beam having a wavelength of 630 to 685 nm is transmitted.

  The obtuse angle from the back side surface 64b of the substantially triangular prism-shaped second dichroic mirror 64 through the second dichroic mirror 64 through the second dichroic mirror 64 through the front side surface 64a of the substantially triangular prism-shaped second dichroic mirror 64. A part of the third-wavelength laser light that is bent and emitted so as to pass through the optical path L2gt reaches the second FMD 65.

  The left-handed circularly polarized third-wavelength laser light reflected from the front side surface 64a of the second dichroic mirror 64 at a substantially right angle passes through the optical path L2e and is positioned above the housing base wall reference portion 7h (FIG. 3B). Applied to second reflective MR68. Since the second reflective MR 68 is provided with the coating 68a that substantially totally reflects the laser light, the laser light applied to the reflective MR 68 is substantially totally reflected.

  The left-handed circularly polarized third-wavelength laser light reflected from the front side surface 64a of the second dichroic mirror 64 (FIG. 7) at a substantially right angle passes through the optical path L2e and passes through the reflective MR 68 (FIG. 3 (B)) at a right angle. The light is reflected at a slight acute angle and passes through the aperture limiting element 69 through the optical path L2fd. The first side surface 69a of the aperture limiting element 69 is shielded by masking a part of the infrared laser beam for CD (second wavelength laser beam) having a wavelength of about 765 to 830 nm, and is used for a DVD having a wavelength of about 630 to 685 nm. A special film 69c that transmits red laser light (third wavelength laser light) without masking is provided. Since such a special film 69c is provided on the first side surface 69a of the aperture limiting element 69, the aperture limiting element 69 is an infrared laser beam for CD having a wavelength of about 765 to 830 nm (second wavelength laser beam). It does not act on red laser light (third wavelength laser light) for DVD having a wavelength of about 630 to 685 nm. Accordingly, even if the left-handed circularly polarized third-wavelength laser light having a red wavelength of about 630 to 685 nm passes through the aperture limiting element 69, no significant change occurs in the left-handed circularly-polarized third wavelength laser light. The left-turn circularly polarized third-wavelength laser light enters the aperture limiting element 69 from the first side surface 69a of the aperture limiting element 69 without being masked, and exits from the second side surface 69b of the aperture limiting element 69. The

  The left-turn circularly polarized third-wavelength laser light transmitted through the aperture limiting element 69 passes through the second OBL 70. The left-turn circularly polarized third-wavelength laser light that is substantially parallel light becomes convergent light by the second OBL 70 and is applied to the signal portion 350 of the DVD-standard optical disk 300.

  When focus servo of the second OBL 70 mounted on a lens holder (not shown) is performed on the optical disc 300, the lens holder including the second OBL 70 is moved along the focus direction Df. In addition, when the tracking servo of the second OBL 70 mounted on the lens holder (not shown) is performed on the optical disc 300, the lens holder including the second OBL 70 is moved along the tracking direction Dr. Further, when tilt control of the second OBL 70 mounted on the lens holder is performed with respect to the optical disc 300, the lens holder including the second OBL 70 is swung along the tilt direction Dt.

The third wavelength laser beam of the diffused light emitted from the second LD 20W (FIG. 7) is converted into a linearly polarized S wave by the second DOE 24 in the optical path L2at, and is changed from the diffused light to the substantially parallel light by the second CL 61 in the optical path L2dt. The second QWP 62 in the optical path L2dt is changed from the linearly polarized S wave to left-handed circularly polarized light, passes through the aperture limiting element 69 in the optical path L2fd (FIG. 3B), and becomes convergent light by the second OBL 70, and DVD The light is condensed on the signal unit 350 of the standard optical disc 300. The laser beam of the third wavelength follows the forward path in this way, and is focused on the DVD standard optical disc 300 as the third medium 300.

  Next, the return path of the third wavelength laser beam reflected from the DVD standard optical disc 300 will be described. When the third wavelength laser light is reflected by the signal unit 350 of the DVD standard optical disk 300, the left-handed circularly polarized third-wavelength laser light becomes right-handed circularly polarized light. The right-turn circularly polarized third-wavelength laser light becomes diffused light, returns through the optical path L2fd, and reaches the second OBL 70. The right-turn circularly polarized third-wavelength laser light that is diffused light becomes substantially parallel light by the second OBL 70. The right-turn circularly polarized third-wavelength laser light that passes through the second OBL 70 and returns to the optical path L2fd passes through the aperture limiting element 69 and reaches the second reflective MR 68.

  The right-turn circularly polarized third-wavelength laser light reflected from the second reflective MR 68 returns to the second dichroic mirror 64 through the optical path L2e (FIG. 7).

  The right-turn circularly polarized third-wavelength laser light reflected by the front side surface 64a of the second dichroic mirror 64 returns to the second QWP 62 through the optical path L2dt. When the third wavelength laser light returns through the optical path L2dt and passes through the second QWP 62, the clockwise circularly polarized third wavelength laser light becomes a linearly polarized P wave. The linearly polarized P-wave third-wavelength laser light transmitted through the second QWP 62 reaches the second CL 61. When the third wavelength laser light returns through the optical path L2dt and passes through the second CL 61, the third wavelength laser light of the substantially parallel linearly polarized P wave is the third wavelength laser light of the linearly polarized P wave of the convergent light. It becomes. The third-wavelength laser light of linearly polarized P wave that has passed through the second CL 61 returns through the optical path L2dt, travels straight through the optical path intersection LX, returns through the optical path L2ct, and is incident on the second PBS 26.

  When the third wavelength laser light returns through the optical path L2dt and passes through the second QWP 62, the clockwise circularly polarized third wavelength laser light becomes a linearly polarized P wave. The third-wavelength laser beam of linearly polarized P wave that has returned the optical path L2dt and passed through the optical path intersection LX reaches the PBS 26 through the optical path L2ct. In the PBS 26, the linearly polarized P wave of the second wavelength laser light or the linearly polarized P wave of the third wavelength laser light travels substantially straight, and the linearly polarized S wave of the second wavelength laser light or the linearly polarized light S of the third wavelength laser light. Since the special film 26c that reflects and transmits the waves at substantially right angles is provided, the linearly polarized P-wave third-wavelength laser light passes through the PBS 26 substantially straight.

  The linearly-polarized P-wavelength third-wavelength laser light transmitted substantially straight through the PBS 26 reaches the second sensor lens 82A through the optical path L2bt. Astigmatism occurs in the third wavelength laser light when the third wavelength laser light of linearly polarized P wave passes through the second sensor lens 82A.

  The third wavelength laser light transmitted through the second sensor lens 82A reaches the second PDIC 92A through the optical path L2bt. The second PDIC 92A receives laser light reflected from the optical disc 300 (FIG. 3B), converts the signal into an electrical signal, and detects information recorded on the optical disc 300. . The second PDIC 92A (FIG. 7) receives the laser beam reflected from the optical disc 300 (FIG. 3B), converts the signal into an electrical signal, and configures the OPU 5 (FIG. 7). This is for operating the servo mechanism of the lens holder with OBL.

The diffused third wavelength laser light reflected by the signal unit 350 of the “DVD” standard optical disc 300 (FIG. 3B) is a left-turned circle when reflected by the signal unit 350 of the optical disc 300. From the polarized light, it becomes a right-handed circularly polarized light, becomes parallel light by the second OBL 70 in the optical path L2fd, and becomes a linearly polarized P-wave from the right-handed circularly polarized light by the second QWP 62 in the optical path L2dt (FIG. 7). The parallel light is changed from the parallel light to the convergent light by the second CL 61, travels substantially straight through the second PBS 26 located at the branch point of the optical path L2at, the optical path L2bt, and the optical path L2ct, and irradiates the second PDIC 92A located at the end of the optical path L2bt. Is done. The third-wavelength laser light reflected from the “DVD” standard optical disc 300 (FIG. 3B) follows the return path in this manner, and is irradiated to the second PDIC 92A (FIG. 7).

  The LDD 9, the LD 10, LD 20W, the expander unit 46, the FMDs 50 and 65, the PDICs 91A and 92A, and the like are connected to an FPC 8B such as the flexible printed circuit body so as to be energized. In the FPC 8B, a plurality of circuit conductors are printed on an insulating sheet made of an aromatic heat-resistant resin such as a fully aromatic polyimide resin (not shown), and a metal foil (not shown) such as a copper foil is juxtaposed on the insulating sheet. Further, a transparent or translucent protective layer (not shown) made of an aromatic heat resistant resin such as a wholly aromatic polyimide resin is provided thereon. By using FPC8B provided with an insulating sheet made of aromatic heat-resistant resin such as wholly aromatic polyimide resin and / or a protective layer, LDD9, LD10, LD20W, expander unit 46, FMD50, 65 are provided for FPC8B. , PDIC 91A, 92A, etc. are soldered well. The FPC 8B is configured as, for example, a standardized FPC 8B that can be used in common with other OPUs.

  The OPU 5 is configured to include the various types described above. Various parts constituting the OPU 5 are mounted on a metal housing 7B. The housing 7B includes a housing main body 7e equipped with various components, and a pair of main shafts that are movably matched with a first shaft member that is projecting from the housing main body 7e and that is not illustrated, and that is movable in a side view. Bearing parts 7p, 7q having a shape and a second part having a substantially straight round bar shape (not shown) projecting from the housing body 7e toward the opposite side to the bearing parts 7p, 7q having a substantially round hole shape when viewed from the side. A shaft portion and a bearing portion 7r having a substantially U shape in a side view, which is movably matched with the shaft member, are formed. The main shaft bearing portions 7p, 7q and the sub shaft bearing portion 7r are integrally formed with the housing body 7e. The main shaft bearing portions 7p and 7q, the sub shaft bearing portion 7r, and the housing main body 7e are formed as one using the same metal material.

  For the housing 7B constituting the OPU 5, for example, a non-ferrous metal such as aluminum (Al), magnesium (Mg), and zinc (Zn), or an alloy containing aluminum (Al), magnesium (Mg), and zinc (Zn) is used. Formed. For example, an aluminum alloy containing aluminum as a main component is used to form the housing 7B. For example, heat generated from a plurality of LDs 10, 20W, etc. is efficiently dissipated to the outside of the housing 7B by the aluminum alloy housing 7B mainly composed of aluminum having excellent heat dissipation. The housing 7B is made of aluminum and is formed as, for example, a standardized housing 7B that can be used in common with other OPUs. The OPU 5 including the housing 7B and the like is assumed to include other components in addition to the illustrated ones, but in FIG. 7, these other components are omitted for convenience.

  For example, when the optical disk apparatus is turned on and the optical disk apparatus is activated, the optical disk 100 (FIG. 2A, FIG. 3A), 200 (FIG. 2B), 300 (FIG. 3 (B)), when the track jump of the OPU 5 (FIG. 7) is performed, the OPU 5 movably supported by the first shaft member and the second shaft member each having a substantially straight round bar shape is substantially in the disk radial direction Dr. Driven along. The OPU 5 is mounted on the first shaft member and the second shaft member having a substantially straight round bar shape so as to be reciprocally movable along the disk radial direction Dr.

The OPU 5 includes the housing 7B, the FPC 8B, the LDD 9, the LD 10, 20W, the DOE 11, 24, the PBS 16, 26, the QWP 17, 62, the CL 41, 61, the beam expander unit 46, and the dichroic mirror 48. 64, FMD 50, 65, MR 58, 68, OBL 60, 70, aperture limiting element 69, sensor lenses 81A, 82A, PDIC 91A, 92A, and the like. The OPU 5 is compatible with optical discs 100 (FIGS. 2A, 3A), 200 (FIG. 2B), and 300 (FIG. 3B) having different standards. ing.

  The OPU 5 (FIG. 7) includes a first LD 10 capable of emitting a first wavelength laser beam, a second LD 20W capable of emitting a second wavelength laser beam having a wavelength different from the first wavelength laser beam, and a first wavelength. At least a first OBL 60 for condensing the laser light on the first optical disc 100 and a second OBL 70 for condensing the second wavelength laser light on the second optical disc 200, which is an optical disc of a standard different from the first optical disc 100. I have.

  The optical paths L1it and L1iit of the first wavelength laser light from the first LD 10 to the first optical disc 100 via the first OBL 60 are defined as the first optical path L1T for convenience. Further, the optical paths L2it and L2iit of the second wavelength laser light from the second LD 20W to the second optical disc 200 via the second OBL 70 are defined as a second optical path L2T for convenience. When the first optical path L1T and the second optical path L2T are thus defined and the OPU 5 is viewed in plan as shown in FIG. 7, the optical layout in the OPU 5 is such that the first optical path L1T and the second optical path L2T are within the housing 7B. For example, the optical layout is substantially cross-shaped and intersects at a substantially right angle.

  By configuring the optical layout in this manner, even if the standard of the first optical disc 100 and the standard of the second optical disc 200 are different, at least the first optical disc 100 and the optical disc having a different standard from the first optical disc 100 are used. Thus, it is possible to provide the OPU 5 corresponding to the second optical disc 200.

  The first LD 10 capable of emitting the first wavelength laser light, the second LD 20W capable of emitting the second wavelength laser light having a different wavelength from the first wavelength laser light, and the first wavelength laser light on the first optical disc 100 If the OPU 5 is configured to include the first OBL 60 that condenses the light and the second OBL 70 that condenses the second wavelength laser light on the second optical disc 200 that is an optical disc of a standard different from the first optical disc 100, A single OPU 5 can at least support, for example, a first optical disc 100 with a high-density recording standard and a second optical disc 200 with a conventional standard different from the first optical disc 100. Therefore, it is possible to provide the OPU 5 corresponding to the various optical discs 100 and 200 of different standards.

  Also, the first optical path L1T, which is the optical path L1it, L1iit of the first wavelength laser light from the first LD 10 to the first optical disc 100 via the first OBL 60, and the second LD 20W via the second OBL 70. An optical layout in which the second optical path L2T, which is the optical paths L2it and L2iit of the second wavelength laser light until reaching the second optical disc 200, intersects at a substantially right angle in a substantially cross shape, for example, in a plan view in the housing 7B. By doing so, the OPU 5 can be reduced in size and thickness. Therefore, it is possible to provide the OPU 5 that is space-saving. Further, when the OPU 5 is viewed in a plan view, the first optical path L1T and the second optical path L2T have an optical layout in which, for example, a substantially cross shape intersects at a substantially right angle in the housing 7B. Optical layout design is facilitated.

  The second LD 20W is configured as an LD 20W that can emit laser light having a plurality of types of wavelengths. More specifically, the second LD 20W is capable of emitting a second wavelength laser beam and a third wavelength laser beam having a different wavelength from the first wavelength laser beam and a different wavelength from the second wavelength laser beam. It is configured as a wavelength LD20W.

When the OPU 5 is equipped with the LD 20W capable of emitting laser beams of a plurality of types of wavelengths typified by the two-wavelength LD 20W, an OPU 5 compatible with various optical discs 100, 200, and 300 is configured. The number of parts can be reduced. For example, the second LD 20W has two types of wavelength laser beams, a second wavelength laser beam and a third wavelength laser beam that has a different wavelength from the first wavelength laser beam and a different wavelength from the second wavelength laser beam. Since it is configured as a two-wavelength LD 20W that can emit light, the OPU 5 equipped with the first LD 10 and the second LD 20W can support various optical discs 100, 200, and 300. At the same time, the LD capable of emitting the second wavelength laser light and the LD capable of emitting the third wavelength laser light are grouped as one LD 20W, so that the parts of the OPU 5 can be reduced, reduced in weight, and reduced in size. Downsizing, lightening and price reduction. Accordingly, it is possible to provide the OPU 5 that can be used for various optical discs 100, 200, and 300 and that is reduced in parts, reduced in weight, reduced in size, reduced in thickness, reduced in price, and the like.

  The third wavelength laser light emitted from the second LD 20W, which is the two wavelength LD 20W, follows the second optical path L2T, which is the same optical path as the optical path followed by the second wavelength laser light, for example, The light is condensed on a third optical disk 300 which is an optical disk having a standard different from that of the optical disk 100 and which is an optical disk having a standard different from that of the second optical disk 200.

  The OPU 5 corresponds to various optical discs 100, 200, 300 including the third optical disc 300 corresponding to the third wavelength laser light. The OPU 5 includes a first optical disc 100 corresponding to the first wavelength laser beam, an optical disc having a standard different from the first optical disc 100, a second optical disc 200 corresponding to the second wavelength laser beam, and a standard different from the first optical disc 100. And an optical disc of a standard different from that of the second optical disc 200, and can be adapted to the third optical disc 300 corresponding to the third wavelength laser beam. For example, the first optical disc 100 is a high-density recording standard optical disc that is not compatible with a conventional standard optical disc, the second optical disc 200 is a conventional standard optical disc, and the third optical disc 300 is more than the second optical disc 200. Even if the optical disk is a high-density recording standard optical disk and includes a conventional optical disk different from the second optical disk 200, the OPU 5 includes the first optical disk 100, the second optical disk 200, and the third optical disk 300. Corresponding to

  The OPU 5 can be mounted on an optical disk device of a PC that can be easily carried, such as a notebook PC or a laptop PC, for example, and has a thickness of about 10 mm or less, specifically a thickness of about 7.3 mm or less. Is formed.

  By adopting the above optical layout in OPU5, it can be installed in an optical disk device of a PC that is easy to carry, such as a notebook PC or a laptop PC, as well as corresponding to various optical disks 100, 200, 300 of different standards. A thin OPU 5 having a thickness of about 10 mm or less, specifically, a thickness of about 7.3 mm or less is configured. Although it depends on the design / specifications of the optical disk device and OPU5 that are easy to carry, such as a notebook PC or laptop PC, it is made thinner due to the minimum size of the various parts that make up the OPU5. It is assumed that the OPU 5 has a thickness of about 2 mm or more, specifically, a thickness of about 3 mm or more.

  The OPU 5 is shipped, for example, to an optical disk device assembly manufacturer or the like, and the optical disk device assembly manufacturer or the like constitutes one optical disk device including only one OPU 5.

  When the OPU 5 is installed in the optical disc apparatus, reading of data from the various optical discs 100, 200, 300 and writing of data to the various optical discs 100, 200, 300 are performed by one optical disc apparatus provided with only one OPU 5. It becomes possible to execute. Various optical discs 100, 200, and 300 are installed in the optical disc device, and for example, data of the various optical discs 100, 200, and 300 are read out, or data is written into the various optical discs 100, 200, and 300, for example. Accordingly, it is possible to provide an optical disc apparatus that can handle various optical discs 100, 200, and 300.

  The OPU 5 is, for example, a read-only optical disk such as “CD-ROM”, “DVD-ROM”, “BD-ROM”, “CD-R”, “DVD-R”, “DVD + R”, “BD-”. For write-once optical discs such as “R”, and write / erase and rewritable optical discs such as “CD-RW”, “DVD-RW”, “DVD + RW”, “DVD-RAM”, “BD-RE”, etc. It is assumed that it corresponds.

  The optical disk device provided with the OPU 5 includes, for example, a notebook personal computer (not shown), a laptop personal computer (not shown), a computer such as a desktop personal computer (not shown), an audio device such as a CD player, It can be installed in an audio / video device (not shown) such as a DVD player. The optical disk device provided with the OPU 5 is capable of supporting a plurality of media such as a CD optical disk, a DVD optical disk, and a Blu-ray Disc.

  The optical pickup device according to the present invention and the optical disc device including the same are not limited to those illustrated or described above.

  For example, in the optical path intersection (LX) of the OPU (5) shown in FIG. 7, the first optical path (L1T) and the second optical path (L2T) may intersect at an inclined angle.

  Further, for example, the P wave or S wave of the Blu-ray Disc system, DVD system, or CD system laser beam may be reversed. Further, the clockwise circularly polarized laser beam and the counterclockwise circularly polarized laser beam may be reversed.

  Further, for example, the DVD-series optical disk 300 may be the second medium (300), and the CD-series optical disk 200 may be the third medium (200) instead.

  Further, for example, the OPU (5) (FIG. 7) in which only data reproduction is performed without writing data to the second media 200 that is the CD-series medium 200 (FIG. 2B). It may be said.

  Further, for example, the OPU (5) corresponds to a read-only optical disk such as “CD-ROM”, “DVD-ROM”, “BD-ROM”, and “CD-R”, “DVD-R”, “ Write / erase and rewrite of write-once optical discs such as DVD + R and BD-R, and CD-RW, DVD-RW, DVD + RW, DVD-RAM, and BD-RE Possible types of optical disks may not be supported.

  Further, the QWP 17 located in the optical path L1ct of the first half optical path L1it that constitutes the first optical path L1T may be located, for example, in the optical path (L1e) of the second half optical path (L1iit) that constitutes the first optical path (L1T). For example, the QWP (17) may not be interposed in the optical path (L1T) and may be omitted. Further, the QWP 62 positioned in the optical path L2dt of the second half optical path L2iit constituting the second optical path L2T may be positioned, for example, in the optical path (L2e) of the second half optical path (L2iit) constituting the second optical path (L2T).

  Further, for example, the first LD (10) is installed at the position where the second LD 20W shown in FIG. 7 is installed, and instead the second LD (10) is installed at the position where the first LD 10 shown in FIG. 20W) may be equipped.

Further, for example, the first OBL (60) and the second OBL (70) located substantially on the disk center side of the housing (7) constituting the OPU (5) are orthogonal to the disk radial direction (Dr). May be arranged along the tangential direction (Ds), which is a direction perpendicular to the focus direction (Df).

  Further, for example, instead of the first OBL 60 for Blu-ray Disc shown in FIGS. 2A and 3A, for example, the optical axis direction Df of the first wavelength laser light irradiated on the first medium 100 A pair of OBLs (not shown) arranged along the lines may be provided in the OPU 5 as OBLs for Blu-ray Discs so that they are overlapped. That is, instead of the first OBL 60 for Blu-ray Disc shown in FIGS. 2 (A) and 3 (A), for example, a pair of OBLs (not shown) arranged in series along the focus direction Df -It may be arranged in OPU5 as OBL for ray disc.

  Further, for example, instead of the one LDD 9 (FIG. 7), a first LDD (not shown) corresponding to the first LD 10 and a second LDD (not shown) corresponding to the second LD 20W are provided. The OPU 5 may be individually installed.

  Further, for example, the optical path L1f between the reflective MR 58 for Blu-ray Disc (FIG. 2 (A), FIG. 3 (A)) and the first OBL 60 for Blu-ray Disc, or Blu-ray Disc In the first optical path L1T such as the optical path L1e between the reflective MR 58 (FIG. 1) and the first dichroic mirror 48 for Blu-ray Disc, the condensing spot S1 (FIG. 2 (A) 3), aberration correction for the spherical aberration and the like generated in FIG. 3A) and correction of either or both of vertical birefringence and in-plane birefringence of the laser light irradiated to the optical disc 100 are performed. A liquid crystal correction element for Blu-ray Disc (not shown) may be further provided.

  Next, a sixth embodiment of the optical pickup device and the optical disk device including the same according to the present invention will be described in detail with reference to FIG. 2, FIG. 3, and FIG.

  FIG. 8 is a schematic view showing a sixth embodiment of the optical pickup device and the optical disk device including the same according to the present invention.

  The focusing detection methods of the condensing spots S1 (FIGS. 2A, 3A), S2 (FIG. 2B), and S3 (FIG. 3B) in the OPU 6 are based on, for example, the knife edge method. Detection method. For example, errors of the focused spots S1, S2, and S3 are detected using knife edges, DOEs 76 and 77 (FIG. 8) having a diffraction grating function, and the like. The OPU 6 is an OPU 6 provided with an optical system based on a knife edge method. The tracking detection method of the condensing spots S1, S2, S3 in the OPU 6 is a detection method based on the differential push-pull method or the phase difference method, as in the OPU 5 (FIG. 7) of the fifth embodiment. The

  Instead of the first PDIC 91A located at the end of the optical path L1it in FIG. 7 and corresponding to the focusing detection method based on the differential astigmatism method, the first corresponding to the focusing detection method based on the knife edge method as shown in FIG. PDIC91B is equipped. Further, instead of the first anamorphic lens 81A located in the optical path L1bt of FIG. 7, a first power lens 81B is provided in the optical path L1bu as shown in FIG. For example, a first power lens 81B is used as the first sensor lens 81B of the OPU 6 in the sixth embodiment. In addition, the first return path DOE 76 for “Blu-ray Disc” is provided in the optical path L1bu between the first PBS 16 and the first sensor lens 81B. The first return path DOE 76 is a DOE having a knife edge formed by a plurality of divided hologram elements such as a four-divided hologram element.

Further, instead of the second PDIC 92A located at the end of the optical path L2it in FIG. 7 and corresponding to the focusing detection method based on the differential astigmatism method, as shown in FIG. 8, it corresponds to the focusing detection method based on the knife edge method. A second PDIC 92B is provided. Further, in place of the second anamorphic lens 82A located in the optical path L2bu in FIG. 7, a second power lens 82B is provided in the optical path L2bu as shown in FIG. For example, a second power lens 82B is used as the second sensor lens 82B of the OPU 6 in the sixth embodiment. Further, a second return path DOE 77 for DVD or CD is provided in the optical path L2bu between the second PBS 26 and the second sensor lens 82B. Similar to the first return path DOE 76, the second return path DOE 77 is a DOE having a knife edge formed by a plurality of divided hologram elements such as a quadrant hologram element. The OPU 6 includes a first return-path DOE 76 and a second return-path DOE 77 each having a knife edge formed by a quadrant hologram element.

  The OPU 5 of the fifth embodiment shown in FIG. 7 and the OPU 6 of the sixth embodiment shown in FIG. However, in other parts, the OPU 5 (FIG. 7) of the fifth embodiment and the OPU 6 (FIG. 8) of the sixth embodiment are the same. For example, as shown in FIGS. 7 and 8, the housing 7 </ b> B is formed as, for example, a standardized housing 7 </ b> B that can be used in common with the OPU 5 and the OPU 6. For example, the FPC 8B is formed as, for example, a standardized FPC 8B that can be used in common with the OPU 5 and the OPU 6. In the OPU 6 of the sixth embodiment shown in FIG. 8, components that are substantially the same as the OPU 5 of the fifth embodiment shown in FIG. 7 are assigned the same reference numerals and detailed descriptions thereof are omitted.

  First, the first wavelength laser beam emitted from the first LD 10 (FIG. 8) passes through the first OBL 60 and passes through the first medium 100 of the “Blu-ray Disc” standard (FIGS. 2A and 3). The optical path until the first wavelength laser beam irradiated and reflected by (A)) reaches the first PDIC 91B (FIG. 8) will be described. The first wavelength laser beam emitted from the first LD 10 passes through the first OBL 60 and is the first medium 100 of the “Blu-ray Disc” standard (FIGS. 2A and 3A). The optical path in the process of being irradiated and reflected and returned to the first PBS 16 (FIG. 8) and the optical path until the first wavelength laser beam reaches the first FMD 50 are described. Since it is the same as the description, the detailed description is omitted.

  It passes through the optical path L1dt of the first optical path L1T, passes through the optical path intersection LX, passes through the optical path L1ct of the first optical path L1T, passes through the first QWP, and becomes a linearly polarized S wave. The first-wavelength laser beam of the linearly polarized S wave in the return path that reaches the first PBS 16 located at the branch point passes through the first PBS 16 substantially straight, passes through the optical path L1bu, and is used for the “Blu-ray Disc”. The first return route DOE 76 is reached. The first wavelength laser beam in the return path that has passed through the first return path DOE 76 passes through the first sensor lens 81B for the “Blu-ray Disc” through the optical path L1bu. The first wavelength laser beam in the return path that has passed through the first sensor lens 81B passes through the optical path L1bu and is applied to the first PDIC 91B for “Blu-ray Disc”.

  Next, the second wavelength laser light emitted from the second LD 20W is transmitted through the second OBL 70 and irradiated to the CD standard second medium 200 (FIG. 2B) and reflected and reflected. The optical path until the second wavelength laser beam reaches the second PDIC 92B (FIG. 8) will be described. The second wavelength laser light emitted from the second LD 20W is transmitted through the second OBL 70 and irradiated to the CD standard second medium 200 (FIG. 2B) and reflected to be reflected by the second laser beam. The optical path explanation in the process of returning to the PBS 26 (FIG. 8) and the optical path explanation until the second wavelength laser beam reaches the second FMD 65 are the same as the optical path explanation in the fifth embodiment. The explanation was omitted.

The second path 26 reaches the second PBS 26 located at the branch point of the optical path L2at, the optical path L2bu, and the optical path L2ct through the optical path L2dt of the second optical path L2T, the optical path intersection LX, the optical path L2ct of the second optical path L2T, and the optical path L2ct. The linearly polarized P-wave second-wavelength laser light travels straight through the second PBS 26, passes through the optical path L2bu, and reaches the second return path DOE 77 for DVD or CD. The laser beam of the second wavelength of the return path that has passed through the second return path DOE 77 passes through the optical path L2bu, the second sensor lens 82B for DVD or CD, and hits the second PDIC 92B for DVD or CD. It is done.

  Next, the third wavelength laser beam emitted from the second LD 20W is transmitted through the second OBL 70 and irradiated to the DVD standard third medium 300 (FIG. 3B) and reflected and reflected. The optical path until the third wavelength laser beam reaches the second PDIC 92B (FIG. 8) will be described. The third wavelength laser light emitted from the second LD 20W is transmitted through the second OBL 70 and irradiated to the DVD standard third medium 300 (FIG. 3B) and reflected to be reflected by the second laser beam. The optical path explanation in the process of returning to the PBS 26 (FIG. 8) and the optical path explanation until the third wavelength laser beam reaches the second FMD 65 are the same as the optical path explanation in the fifth embodiment. The explanation was omitted.

  The third wavelength laser light of the linearly polarized P wave in the return path that has passed through the optical path L2dt of the second optical path L2T, passed through the optical path intersection LX, passed through the optical path L2ct of the second optical path L2T, and reached the second PBS 26 is the second PBS 26 The vehicle travels substantially straight and passes through the optical path L2bu to reach the second return path DOE 77 for DVD or CD. The laser beam of the third wavelength of the return path that has passed through the second return path DOE 77 passes through the optical path L2bu, the second sensor lens 82B for DVD or CD, and hits the second PDIC 92B for DVD or CD. It is done.

  As mentioned above, although embodiment of this invention was described, embodiment mentioned above is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed / improved without departing from the gist thereof, and equivalents thereof are also included.

1 is a schematic diagram showing a first embodiment of an optical pickup device according to the present invention and an optical disk device including the same. (A) is explanatory drawing which shows the state in which 1st wavelength light is irradiated to a 1st medium, (B) is explanatory drawing which shows the state in which 2nd wavelength light is irradiated to a 2nd medium. (A) is explanatory drawing which shows the state in which 1st wavelength light is irradiated to a 1st medium, (B) is explanatory drawing which shows the state in which 3rd wavelength light is irradiated to a 3rd medium. It is the schematic which shows 2nd embodiment of the optical pick-up apparatus which concerns on this invention, and an optical disk apparatus provided with the same. It is the schematic which shows 3rd embodiment of the optical pick-up apparatus which concerns on this invention, and an optical disk apparatus provided with the same. It is the schematic which shows 4th embodiment of the optical pick-up apparatus which concerns on this invention, and an optical disk apparatus provided with the same. It is the schematic which shows 5th embodiment of the optical pick-up apparatus which concerns on this invention, and an optical disk apparatus provided with the same. It is the schematic which shows 6th embodiment of the optical pick-up apparatus which concerns on this invention, and an optical disk apparatus provided with the same. It is the schematic which shows one form of the conventional optical pick-up apparatus.

Explanation of symbols

1,2,3,4,5,6 OPU (Optical Pickup Device)
7A, 7B Housing 7d, 7e Housing body 7p, 7q, 7r Bearing 7h Housing base wall reference part (base wall reference part)
8A, 8B FPC (flexible substrate)
9 LDD (Laser Driver)
10, 20, 20W, 30 LD (light emitting device)
11, 21, 24, 31, 75, 76, 77 DOE (diffractive optical element)
16, 25, 26, 35, 40 PBS (polarizing member)
16a, 25a, 26a, 35a, 40a First member 16b, 25b, 26b, 35b, 40b Second member 16c, 25c, 26c, 35c, 58a, 68a, 69c Film (film)
17, 57, 62, 67 QWP (1/4 wavelength plate)
20a light emitting unit 20b PDIC (light detection unit)
20c cover 22 hologram laser diode unit 23 divergent lens (coupling lens)
37 LCD (polarization direction conversion member)
38 HWP (polarization direction conversion member)
40c Polarizing film (film)
41, 61 CL (collimator lens)
42, 42t Holding member 43 Guide member 44 Base 45, 46 Beam expander unit (expander unit)
48, 63, 64 Dichroic mirror (mirror)
48a, 63a, 64a Front side (surface)
48b, 63b, 64b Back side (surface)
48c, 63c, 64c Dichroic membrane (membrane)
50, 65 FMD (light receiving element)
52 Liquid crystal correction element 58, 68 MR (mirror)
60,70 OBL (objective lens)
69 Opening limiting element 69a First side surface (side surface)
69b Second side (side)
80A, 80B, 81A, 81B, 82A, 82B Sensor lens (lens)
90A, 90B, 91A, 91B, 92A, 92B PDIC (light detector)
100, 200, 300 Optical disc (media)
110, 120, 210, 310, 320 Substrate 110t, 120t, 210t, 220t, 310t, 320t Thickness 150, 250, 350 Signal surface part (signal part)
220 layers (substrate)
Df Focus direction (direction)
Dr Tracking direction (direction)
Ds Tangential direction (direction)
Dt Tilt direction (direction)
L1, L1T First optical path (optical path)
L1i, L1it, L1ii, L1iit, L1a, L1at, L1b, L1bt, L1bu, L1c, L1cr, L1ct, L1d, L1dt, L1e, L1f, L1g, L2i, L2it, L2ii, L2iiL, b2L L2bt, L2bu, L2c, L2ct, L2d, L2dt, L2e, L2fc, L2fd, L2g, L
2gt, L2h optical path L2, L2T second optical path (optical path)
LA1, LA2 Optical axis LX Optical path intersection S1, S2, S3 Condensing spot (spot)
WDb, WDc, WDd Working distance (working distance)

Claims (20)

A first light emitting element capable of emitting a first wavelength light;
A second light emitting element capable of emitting second wavelength light having a wavelength different from that of the first wavelength light;
A first objective lens for condensing the first wavelength light on a first medium;
A second objective lens that focuses the second wavelength light on a second medium of a standard medium different from the first medium;
Comprising at least
The optical path of the first wavelength light from the first light emitting element to the first medium via the first objective lens is defined as a first optical path,
When the optical path of the second wavelength light from the second light emitting element to the second medium via the second objective lens is defined as a second optical path,
The optical pickup device, wherein the first optical path and the second optical path intersect. The optical pickup device according to claim 1, further comprising a polarizing member that guides the first wavelength light to an optical path passing through the first objective lens or an optical path passing through the second objective lens. When the first wavelength light is transmitted through the polarizing member, the first wavelength light passes through the first objective lens,
The optical pickup device according to claim 2, wherein when the first wavelength light is reflected by the polarizing member, the first wavelength light passes through the second objective lens. 4. The optical pickup device according to claim 2, wherein the second wavelength light is guided to an optical path passing through the second objective lens by the polarizing member. 5. The optical pickup device according to any one of claims 2 to 4, wherein the second wavelength light passes through the polarizing member and passes through the second objective lens. The optical pickup device according to any one of claims 2 to 5, wherein the polarizing member is located at an optical path intersection where the first optical path and the second optical path intersect. The first wavelength light passes through the polarizing member and passes through the first objective lens when the first wavelength light passing through the polarizing member is a P wave. 7. The optical pickup device according to any one of 6 above. The first wavelength light is reflected by the polarizing member and passes through the second objective lens when the first wavelength light passing through the polarizing member is an S wave. The optical pickup device according to any one of? 7. The optical pickup device according to any one of claims 2 to 8, further comprising a polarization direction conversion member capable of polarizing the first wavelength light. The optical pickup device according to claim 9, wherein the polarization direction conversion member is positioned between the first light emitting element and the polarization member. The optical pickup device according to claim 9 or 10, wherein a liquid crystal element capable of polarizing the first wavelength light into P wave or S wave is used as the polarization direction changing member. 11. The optical pickup device according to claim 9, wherein a half-wave plate capable of polarizing the first wavelength light into a P wave or an S wave is used as the polarization direction conversion member. 13. A third light-emitting element capable of emitting a third wavelength light having a wavelength different from that of the first wavelength light and a wavelength different from that of the second wavelength light is provided. 2. An optical pickup device according to item 1. The third wavelength light is guided to the optical path passing through the second objective lens by a polarizing member that guides the first wavelength light to the optical path passing through the first objective lens or the optical path passing through the second objective lens. 14. The optical pickup device according to claim 13, wherein the optical pickup device is used. The optical pickup device according to claim 14, wherein the third wavelength light is reflected by the polarizing member and passes through the second objective lens. The third wavelength light is condensed by the second objective lens onto a third medium that is a standard medium different from the first medium and a standard medium different from the second medium. The optical pickup device according to any one of claims 13 to 15. The second light emitting element is
The second wavelength light;
A third wavelength light having a wavelength different from the first wavelength light and a wavelength different from the second wavelength light;
The optical pickup device according to claim 1, wherein the optical pickup device emits a plurality of types of wavelength light that can emit light. The third wavelength light follows the second optical path which is the same optical path as the second wavelength light follows, and is changed to a standard medium different from the first medium by the second objective lens and the second optical path. The optical pickup device according to claim 17, wherein the optical pickup device is focused on a third medium that is a standard medium different from the medium. The optical pickup device according to any one of claims 1 to 18, wherein the optical pickup device can be installed in a computer that is easy to carry. An optical disc device comprising the optical pickup device according to claim 1.

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