JP2008269666A - Optical pickup and optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily switch the optical path of light beams composed of the same wavelength by a simple configuration. <P>SOLUTION: Since the optical path of the light beam 1 can be changed by switching the operation mode of a dimming mirror 17 corresponding to the discriminated result of an optical disk 100 by a control part 2, the optical pickup 7 of the optical disk device 1 can irradiate the optical disk 100B for BD with the light beam L1 through an objective lens 10 and can irradiate an optical disk 100H for HD with the light beam L1 through an objective lens 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup and an optical disc apparatus, and is suitable for application to, for example, an optical disc apparatus compatible with both a BD (Blu-ray Disc, registered trademark) system and an HD DVD (High Density Digital Versatile Disc, registered trademark) system. Is.

  2. Description of the Related Art Conventionally, in an optical disc apparatus, there are widely used devices that record information such as music content, video content, application programs, and various data on an optical disc as an information recording medium, and can read and reproduce such information. It is popular.

  In particular, in recent years, an optical disc apparatus compatible with the BD system using blue laser light having a wavelength of about 405 [nm] has been put into practical use. In the BD system, a laser beam with a much shorter wavelength is used compared to the conventional CD (Compact Disc) system, DVD (Digital Versatile Disc) system, etc., so CDs and DVDs having the same disk diameter, etc. It has a larger recording capacity.

  In addition, a three-wavelength optical disk device has been proposed which can be adapted to BD optical disks as well as conventional CD or DVD optical disks (see, for example, Patent Document 1).

  As described above, the wavelength of the laser beam for BD is 405 [nm], and its wavelength is greatly different from the laser beam for CD and DVD, so it is difficult to design an objective lens for sharing these three wavelengths. is there. For this reason, it is practical to provide two objective lenses for BD and CD / DVD in an optical pickup in an optical disc apparatus that supports three wavelengths.

Accordingly, in such an optical disc apparatus, a light beam having a different wavelength is transmitted or reflected by a dichroic prism or the like in accordance with the wavelength of the light beam, and the optical path is switched, whereby an objective lens for CD / DVD or an objective for BD is used. An optical disk is irradiated with the light beam through a lens.
JP 2006-134474 A

  By the way, as a large-capacity optical disk using a blue laser, the HD DVD (registered trademark) system (hereinafter referred to as the HD system) has been put to practical use in addition to the BD described above. In this HD system, a laser beam having a wavelength equivalent to that of the BD system (405 [nm]) is used, but the thickness from the surface of the irradiated surface irradiated with the light beam in the optical disk to the signal recording layer on which the signal is recorded. The so-called cover layer thickness and the NA (Numerical Aperture) of the objective lens for condensing the light beam are different from those of the BD system.

  In practice, the optical disc 100B for BD is defined to have a cover layer thickness of about 0.1 [mm] and an objective lens NA of about 0.85. On the other hand, in the HD optical disc 100H, the thickness of the cover layer is defined as approximately 0.6 [mm], and the NA of the objective lens is defined as approximately 0.65.

  Therefore, when the optical disk apparatus is compatible with both the BD system and the HD system, it is considered difficult to design an objective lens that can support both the BD system and the HD system for the optical pickup. It is conceivable to separately provide an objective lens for BD and an objective lens for HD DVD.

  On the other hand, as described above, since both the BD laser beam and the HD laser beam are blue laser beams having a wavelength of about 405 [nm], these two laser beams are emitted from a common laser light source. In this case, the optical pickup can be simplified and downsized. In this case, in the optical pickup, it is necessary to switch the laser light having the same wavelength emitted from the single laser light source to the BD system objective lens or the HD system objective lens according to the application.

  However, since the wavelengths of the light beams to be switched are almost the same, the dichroic prism that reflects or transmits the light beam by wavelength selectivity has a problem that the optical path cannot be switched appropriately.

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose an optical pickup and an optical disc apparatus capable of easily switching the optical path of a light beam having the same wavelength with a simple configuration.

  In order to solve such a problem, the optical pickup of the present invention is an optical pickup that irradiates the first or second optical disc with a light beam emitted from the same light source via the first or second objective lens. The light beam is reflected to be bent in the normal direction of the information recording surface of the optical disk and guided to the first objective lens, and the light beam is transmitted to the normal direction of the information recording surface by a predetermined rising mirror. A dimming mirror that leads to the bent second objective lens, and reflects the light beam when irradiating the first optical disk with the light beam, and transmits the light beam when irradiating the second optical disk with the light beam. Thus, a dimming control unit for controlling the reflectance of the light beam in the dimming mirror is provided.

  By switching the optical path of the light beam using the dimming mirror, it is possible to irradiate the first optical disk with the light beam via the first objective lens without using a wave plate or the like for adjusting the polarization direction. The second optical disk can be irradiated with a light beam via the second objective lens.

  The optical disk apparatus of the present invention is an optical disk apparatus that irradiates the first or second optical disk with a light beam emitted from the same light source via the first or second objective lens, and the optical disk is the first optical disk apparatus. A discriminating unit for discriminating between the optical disc and the second optical disc, and the light beam is reflected to bend in the normal direction of the information recording surface of the optical disc and guided to the first objective lens, and the light beam The light beam is irradiated onto the first optical disc in accordance with the light control mirror which is bent in the normal direction of the information recording surface and guided to the second objective lens by transmitting the light and is guided to the second objective lens. The reflectivity of the light beam at the light control mirror is such that the light beam is reflected when the second optical disc is irradiated and the light beam is transmitted when the second optical disc is irradiated with the light beam. And to provide a control for dimming control unit.

  Thus, by switching the optical path of the light beam using the dimming mirror, the light beam is irradiated to the first optical disk via the first objective lens without using a wave plate for adjusting the polarization direction. In addition, the second optical disk can be irradiated with a light beam via the second objective lens.

  According to the present invention, by switching the optical path of the light beam using the dimming mirror, it is not necessary to use a wave plate or the like for adjusting the polarization direction, and the light is transmitted to the first optical disc via the first objective lens. An optical pickup capable of irradiating a beam and irradiating the second optical disk with a light beam through the second objective lens, and thus easily switching the optical path of the light beam having the same wavelength with a simple configuration; An optical disk device can be realized.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) First Embodiment (1-1) Overall Configuration of Optical Disc Device In FIG. 1, an optical disc device 1 according to the first embodiment is configured around a control unit 2 and The information can be recorded and the information can be reproduced from the optical disc 100.

  The control unit 2 includes a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) in which various programs are stored, and a RAM (Random Access Memory) used as a work memory for the CPU. The optical disc apparatus 1 is controlled in an integrated manner.

  That is, the control unit 2 rotates the spindle motor 5 via the drive unit 3 to rotate the optical disc 100 placed on a turntable (not shown) at a desired speed. Further, the control unit 2 drives the sled motor 6 via the drive unit 3 to move the optical pickup 7 along the movement axes G1 and G2 toward the inner peripheral side or the outer peripheral side of the optical disc 100 as shown in FIG. It is moved greatly in the tracking direction, which is the direction to go.

  Hereinafter, for convenience of description, the tracking direction toward the inner or outer peripheral side of the optical disc 100 is also referred to as a radial direction, and the direction orthogonal to the radial direction is also referred to as a tangential direction.

  Further, the control unit 2 drives and controls the biaxial actuator 8 via the driving unit 3 (FIG. 1), thereby causing the objective lens holder 9 on which the objective lenses 10 and 11 are mounted to approach or separate from the optical disc 100. And move it in the tracking direction finely.

  The control unit 2 controls the positions of the objective lenses 10 and 11 as described above, and then irradiates the optical disk 100 with the light beam by the optical pickup 7 and detects the reflected light, thereby reproducing and recording information. It is made to do processing.

  By the way, the optical disc apparatus 1 includes an optical disc 100 (hereinafter referred to as a BD optical disc 100B) and an HD DVD (High Density Digital Versatile Disc (registered trademark)). 100 (hereinafter referred to as HD optical disc 100H).

  For this reason, when the optical disc 100 is loaded, the control unit 2 first performs disc discrimination processing such as reading out information related to the type of the optical disc 100 from a TOC (Table of Contents) area or the like of the optical disc 100, thereby It is determined whether 100 is a BD optical disc 100B or an HD optical disc 100H.

  After that, the optical disc apparatus 1 is configured to irradiate the BD optical disc 100B or the HD optical disc 100H with the light beam by appropriately switching the two types of objective lenses 10 and 11 based on the determination result. (Details will be described later).

(1-2) Configuration of Objective Lens Holder As shown in FIG. 3A, which is an enlarged top view of a part of the optical pickup 7, the objective lens holder 9 includes four support wires 23 </ b> A and 23 </ b> B from the optical pickup 7. , 23C and 23D through a swingable support. For convenience of explanation, the direction supported by the optical pickup 7 (FIG. 2) by the support wires 23A to 23D is defined as the rear direction, and the opposite direction is defined as the front direction.

  The objective lens holder 9 is formed by molding a predetermined resin material, and has a shape in which the lower surface is removed from a hollow rectangular parallelepiped as a whole. As a result, the objective lens holder 9 can enter the interior space of the objective lens holder 9 without interfering with the light control mirror 17 and the rising mirror 18 described later.

  In addition, a hole 9 </ b> A for allowing the light beam to pass through is provided in the front center portion of the objective lens holder 9.

  The objective lens holder 9 is provided with coils 8AC and 8BC on the outer peripheral side and inner peripheral side of the hole 9A on the front surface, respectively, and a coil 8CC is provided on the central portion on the rear surface. On the other hand, magnets 8AM to 8CM are fixed to the optical pickup 7 so as to face the coils 8AC to 8CC, and actuators 8A to 8C are configured by combinations of the coils and the magnets.

  That is, the actuators 8A to 8C are connected to the magnets 8AM to 8CM by supplying the drive signals supplied from the drive unit 3 (FIG. 1) via the support wires 23A to 23D to the coils 8AC to 8CC. Generates thrust. As a result, the actuators 8A to 8C can drive the objective lens holder 9 upward or downward (that is, the focus direction) with respect to the optical pickup 7, or can be driven in the outer peripheral direction or the inner peripheral direction (that is, the tracking direction). Has been made.

(1-3) Configuration of Optical Pickup As shown in FIGS. 4A and 4B, the optical pickup 7 has a plurality of optical components such as a laser diode 12 and a photodetector 21. Based on the control, the optical disk 100 is irradiated with a light beam and the reflected light beam is detected.

  For example, when the control unit 2 receives a reproduction command for reproducing information recorded on the optical disc 100 from the external device (not shown) in a state where the optical disc 100 is loaded, Is supplied to the optical pickup 7.

  In response to this, the optical pickup 7 (FIG. 4A) emits a laser beam having a predetermined light quantity from the laser diode 12 having a wavelength of 405 [nm] as a light beam L1 and enters the inline grating 13.

  The in-line grating 13 splits the light beam L1 into a main light beam L1A for tracking control and sub-light beams L1B and L1C, both of which are incident on the polarization beam splitter.

  Incidentally, the main light beam L1A and the sub light beams L1B and L1C are in a state where their respective optical axes (not shown) are parallel and slightly separated from each other and travel in substantially the same optical path. The beam L1A and the sub light beams L1B and L1C are collectively referred to as a light beam L1.

  The polarization beam splitter 14 has a reflection / transmission surface 14S that reflects or transmits a light beam according to the polarization direction. In practice, the polarization beam splitter 14 reflects the light beam L1 made of, for example, p-polarized light at the reflection / transmission surface 14S and makes it incident on the collimator 15.

  The collimator 15 converts the light beam L1 from divergent light to parallel light and makes it incident on the quarter-wave plate 16. The quarter-wave plate 16 converts the polarization state of the light beam from linearly polarized light to circularly polarized light or from circularly polarized light to linearly polarized light. For example, the light beam L1 composed of p-polarized light is converted to left circularly polarized light. Then, the light beam L1 is applied to the light control mirror 17.

  The dimming mirror 17 has a dimming function for changing the transmittance and the reflectance of the light beam by the applied voltage. Incidentally, the dimming mirror 17 has a plurality of special thin films formed on the surface of the glass substrate, and a voltage is applied to the thin film.

  In practice, as shown schematically in FIG. 5A, the dimming mirror 17 increases the light reflectance when the predetermined switch SW is in an open state and the predetermined voltage E is not applied. The beam L1 is reflected (hereinafter referred to as a reflection mode).

  On the other hand, as shown in FIG. 5B, the dimming mirror 17 reduces the light reflectance when the switch SW is closed and the voltage E is applied, that is, the light transmittance L1 is increased. (Hereinafter, this is referred to as a transmission mode).

  Incidentally, when the change of the reflectance in the reflection mode and the transmission mode in the light control mirror 17 was examined while changing the wavelength of the light beam L1, characteristic curves Q1 and Q2 as shown in FIG. 6 were obtained. As can be seen from the characteristic curves Q1 and Q2, the dimming mirror 17 can obtain a reflectance of approximately 100% in the reflection mode when the wavelength of the light beam L1 is 405 [nm]. Can obtain a reflectance of about 30 [%], that is, a transmittance of about 70 [%].

  Here, the control unit 2 changes the optical path of the light beam L1 by switching the operation mode of the dimming mirror 17 based on the disc discrimination result for the optical disc 100. That is, when the optical disc 100 is the BD optical disc 100B, the control unit 2 switches the dimming mirror 17 to the reflection mode. On the other hand, when the optical disc 100 is the HD optical disc 100H, the control unit 2 turns the dimming mirror 17 on. The mode is switched to the transmission mode.

  As a result, the dimming mirror 17 reflects the light beam L1 toward the near side of the drawing when switched to the reflection mode. At this time, the light beam L1 is incident on the objective lens 10 in FIG. 4B showing a state in which a part of FIG. Incidentally, the polarization direction of the circularly polarized light is reversed at the time of reflection, and the light beam L1 is converted from left circularly polarized light to right circularly polarized light, for example.

  The objective lens 10 has optical characteristics matched to the BD optical disc 100B, condenses the light beam L1 with NA of 0.85, and irradiates the signal recording layer 100BS of the BD optical disc 100B.

  Incidentally, the objective lens 10 irradiates the desired track of the signal recording layer 100BS with the main light beam L1A, which is split by the in-line grating 13, out of the light beam L1, and the sub light beams L1B and L1C are adjacent to the desired track. Irradiate the circumferential track and the outer track.

  The light beam L1 is reflected by the signal recording layer 100BS, and at this time, the rotational direction of the circularly polarized light is reversed, and converted from, for example, right circularly polarized light to left circularly polarized light. Hereinafter, the reflected light beam is referred to as a reflected light beam L2. Incidentally, the reflected light beam L2 is actually composed of three light beams, like the light beam L1, but is collectively referred to as a reflected light beam L2 for convenience.

  The reflected light beam L2 is converted into parallel light by the objective lens 10 by sequentially following the optical path of the light beam L1 in the opposite direction, reflected by the dimming mirror 17, and converted from left circularly polarized light to right circularly polarized light, for example. For example, the light is converted from right circularly polarized light to s-polarized light (that is, linearly polarized light) by the quarter-wave plate 16, further converted to convergent light by the collimator 15, and then incident on the polarization beam splitter 14.

  The polarization beam splitter 14 transmits the reflected light beam L2 made of, for example, s-polarized light through the reflection / transmission surface 14S and enters the multi-lens 20. The multi-lens 20 adjusts the return path magnification to the reflected light beam L2 and has astigmatism for generating a focus error signal, and irradiates the photodetector 21 with it.

  The photodetector 21 is provided so that a predetermined number of detection areas have a predetermined arrangement pattern. Each of the detection areas receives a part of the reflected light beam L2 and performs signal processing on a detection signal corresponding to the reception result. It supplies to each part 4 (FIG. 1).

  The signal processing unit 4 generates a focus error signal, a tracking error signal, and the like by performing predetermined arithmetic processing on the plurality of supplied detection signals, and supplies them to the driving unit 3 to thereby perform feedback processing. Focus control and tracking control are performed.

  Further, the signal processing unit 4 performs a predetermined calculation process on the supplied plurality of detection signals to generate a reproduction RF signal representing recorded information, and further performs a predetermined demodulation process, a decoding process, etc. To generate a reproduction signal, and supply the reproduction signal to the control unit 2. In response to this, the control unit 2 supplies the supplied reproduction signal to an external device (not shown).

  On the other hand, when the dimming mirror 17 (FIG. 4A) is switched to the transmission mode, the light beam L1 is transmitted and reflected by the rising mirror 18 toward the front of the figure. At this time, the light beam L1 is incident on the objective lens 11 as shown in FIG. Incidentally, when the light beam L1 is reflected by the rising mirror 18, the polarization direction of the circularly polarized light is reversed, and is converted from, for example, left circularly polarized light to right circularly polarized light.

  The objective lens 11 has optical characteristics matched to the HD optical disc 100H, condenses the light beam L1 with NA of 0.65, and irradiates the signal recording layer 100HS of the HD optical disc 100H.

  The reflected light beam L2 formed by reflecting the light beam L1 on the signal recording layer 100HS is finally irradiated to the photodetector 21 in the same manner as in the case of the BD optical disc 100B by sequentially following the optical path of the light beam L1 in the opposite direction. Is done.

  The photodetector 21 supplies a detection signal corresponding to the light reception result of the reflected light beam L2 to the signal processing unit 4 (FIG. 1). In response to this, the signal processing unit 4 generates a focus error signal, a tracking error signal, a reproduction signal, and the like based on the detection signal, and supplies them to the control unit 2.

  In this way, when the dimming mirror 17 is switched to the reflection mode, the optical pickup 7 reflects the light beam L1 to irradiate the BD optical disc 100B via the objective lens 10, while switching to the transmission mode. In this case, the HD optical disc 100H is irradiated through the rising mirror 18 and the objective lens 11 by transmitting the light beam L1.

  Further, the control unit 2 switches the operation mode of the dimming mirror 17 based on the determination result of the optical disc 100, so that when the optical disc 100 is the BD optical disc 100B, the dimming mirror 17 is switched to the reflection mode. When the optical disk 100B is irradiated with the light beam L1 and the optical disk 100 is the HD optical disk 100H, the light control mirror 17 is switched to the transmission mode so that the optical beam 100H is irradiated with the light beam L1. Has been made.

  Incidentally, even when a recording command for recording information on the optical disc 100 is received from an external device (not shown), the control unit 2 discriminates the disc type of the optical disc 100 as in the case of receiving a playback command, and the discrimination. According to the result, the operation mode of the light control mirror 17 is switched to change the optical path of the light beam L1, so that the optical beam 100 is irradiated with the light beam L1 via the objective lens 10 or 11 corresponding to the type of the optical disk 100. Has been made.

(1-4) Operation and Effect In the above configuration, when the optical disk 100 is loaded, the control unit 2 of the optical disk device 1 according to the first embodiment performs a predetermined disk discrimination process to thereby perform the optical disk 100. Is the BD optical disc 100B or the HD optical disc 100H.

  Thereafter, when recording information on the optical disc 100 or reproducing information from the optical disc 100, the control unit 2 switches the operation mode of the dimming mirror 17 according to the determination result of the optical disc 100, thereby 7 changes the optical path of the light beam L1. Accordingly, the control unit 2 irradiates the light beam L1 via the objective lens 10 to the BD optical disc 100B and the objective lens 11 to the HD optical disc 100H.

  Therefore, since the optical pickup 7 can switch the optical path of the light beam L1 by the dimming mirror 17 based on the discrimination result of the optical disk 100 by the control unit 2, the light beam L1 is transmitted through the objective lens 10 to the BD optical disk 100B. And the HD optical disc 100H can be irradiated with the light beam L1 through the objective lens 11.

  At this time, the optical pickup 7 can switch the reflectance of the dimming mirror 17 only by controlling the voltage applied to the dimming mirror 17 by the control unit 2, for example, mechanically using a movable part. Compared with the case where the optical path is switched, the risk that the optical path cannot be switched correctly due to an operation failure of a mechanical part or the like can be extremely reduced, and a reliable switching operation can be expected.

  Further, since the optical pickup 7 switches the optical paths of the light beam L1 and the reflected light beam L2 by the dimming mirror 17, for example, the polarization direction of the light beam L1 is adjusted by a half-wave plate or the like, and the polarization beam splitter or the like adjusts the polarization direction. Compared with the case where only a part of the light beam L1 is transmitted, the light beam emitted from the laser diode 12 can be used with high efficiency.

  Furthermore, when thinning the optical disk device and the optical pickup, it is necessary to suppress the thickness at the portion where the objective lens is provided, so that the light beam traveling substantially parallel to the recording surface of the optical disk is directed in the normal direction of the recording surface. There is a problem that optical components such as a wave plate other than the prisms and mirrors that are bent to each other cannot be provided in the thickness direction, and the arrangement of the optical components and the design of the optical path are limited.

  On the other hand, the optical pickup 7 does not switch the optical path of the light beam by a combination of a half-wave plate and a polarizing beam splitter as used in other optical pickups. Therefore, the optical pickup 7 does not need to be provided with a wave plate or the like between the dimming mirror 17 and the objective lens 10 or between the rising mirror 18 and the objective lens 11, and can be configured to be thin overall. it can.

  Further, in the optical pickup 7, as shown in FIG. 6, the dimming mirror 17 can not only adjust the reflectance for the laser light having the wavelength of 405 [nm], but also the reflectance for the laser light of other wavelengths is effective. Can be adjusted. For this reason, the optical pickup 7 can appropriately reflect or transmit the light beam L1 even if the wavelength of the light beam L1 slightly fluctuates from the ideal 405 [nm] due to temperature change in the laser diode 12 or the like. it can.

  Incidentally, as shown in FIG. 6, the dimming mirror 17 uses the light beam L1 as compared with the point that the reflectance in the reflection mode is about 100% because the transmittance in the transmission mode is about 30%. The efficiency will be reduced.

  From such a viewpoint, the optical pickup 7 combines the BD method that requires the light amount of the light beam L1 and the reflection mode, and the HD method and the transmission mode that require a relatively small amount of light, thereby combining the light beam. The amount of light L1 can be used effectively.

  For comparison with the optical pickup 7, the optical pickup 30 in which the objective lenses 10 and 11 are arranged in the radial direction is shown in FIGS. Shown in

  In FIG. 8, the optical pickup 30 is provided with a polarization switching type half-wave plate 31 and a polarization beam splitter 32 instead of the dimming mirror 17. The optical pickup 30 includes collimators 33 and 37 corresponding to the collimator 15, quarter-wave plates 34 and 38 corresponding to the quarter-wave plate 16, a rising mirror 35 corresponding to the rising mirror 18, and a light beam. A mirror 36 and the like for changing the traveling direction of L1 are provided.

  For example, when the optical disc 100 is the BD optical disc 100B, the optical pickup 30 transmits the light beam L1 on the reflection / transmission surface of the polarization beam splitter 32 by adjusting the polarization direction of the polarization switching type half-wave plate 31. Then, the light is reflected by the rising mirror 35 through the collimator 33 and the quarter wavelength plate 34 and is incident on the objective lens 10.

  On the other hand, when the optical disc 100 is the HD optical disc 100H, the optical pickup 30 adjusts the polarization direction of the polarization switching type half-wave plate 31 to adjust the light beam L1 on the reflection / transmission surface of the polarization beam splitter 32. The light is reflected, reflected again by the mirror 36, reflected by the rising mirror 35 through the collimator 37 and the quarter wavelength plate 38, and incident on the objective lens 11.

  Here, as shown in FIG. 7, the objective lens holder 39 corresponding to the objective lens holder 9 includes support wires 23 </ b> A to 23 </ b> D and a light beam that support the objective lens holder 39 so as to be able to swing in the tracking direction (that is, the radial direction). From the viewpoint of preventing interference with L1 and from the viewpoint of thinning, the incident direction of the light beam L1 is limited from the front side.

  That is, the objective lens holder 39 is restricted so that the objective lenses 10 and 11 are arranged along the radial direction on the upper surface thereof.

  In this case, as shown in FIG. 8 (B) corresponding to FIG. 6 (B), the objective lens holder 39 needs to substantially allow two light beams to pass through the hole 39A provided in the center of the front surface. In addition, since the opening is relatively large in the radial direction and it is difficult to provide a rib or the like to prevent interference with the upright mirror 35, there is a possibility that the rigidity is insufficient.

  On the other hand, in the optical pickup 7 according to the present invention, as shown in FIGS. 3 (A) and 3 (B), the hole 9A to the extent that only one light beam can pass through the objective lens holder 9. And the reduction in rigidity of the objective lens holder 9 can be minimized.

  The optical pickup 7 applies thrust in a balanced manner by the actuators 8A to 8C so as to sandwich the objective lenses 10 and 11 having a relatively large weight ratio in the objective lens holder 9 from both the front and rear sides. Compared with the case where thrust is applied only from one side of the objective lenses 10 and 11, the objective lens holder 9 can be stably driven while suppressing unnecessary vibrations and the like.

  According to the above configuration, the optical pickup 7 of the optical disc apparatus 1 can change the optical path of the light beam L1 by switching the operation mode of the dimming mirror 17 according to the discrimination result of the optical disc 100 by the control unit 2. Therefore, the light beam L1 can be applied to the BD optical disc 100B via the objective lens 10, and the light beam L1 can be applied to the HD optical disc 100H via the objective lens 11.

(2) Second Embodiment (2-1) Configuration of Optical Disc Device and Optical Pickup As shown in FIG. 1, the optical disc device 40 according to the second embodiment is an optical disc device according to the first embodiment. 1 is different from the optical pickup 7 in that an optical pickup 47 is provided and an objective lens holder 49 is provided in place of the objective lens holder 9, but the other configuration is the same.

  In the optical pickup 47, as shown in FIG. 9 in which the same reference numerals are assigned to the corresponding parts in FIG. 4, optical components such as a laser diode 12 and a photodetector are provided below the dimming mirror 17, and the light beam L1 is transmitted. The difference is that the light is incident from below the light control mirror 17 and the reflected light beam L2 is emitted downward.

  Incidentally, although the objective lens holder 49 has a configuration similar to that of the objective lens holder 9 (FIG. 3), it is different in that the hole 9A is not provided in order to allow the light beam L1 to enter from below (see FIG. 3). Not shown).

  As in the first embodiment, when the optical disc 100 is the BD optical disc 100B, the control unit 2 switches the dimming mirror 17 to the reflection mode, while the optical disc 100 is similar to the first embodiment. Is the HD optical disc 100H, the light control mirror 17 is switched to the transmission mode.

  When the light control mirror 17 is switched to the reflection mode, the light mirror L1 reflects the light beam L1, reflects it again by the rising mirror 18, enters the objective lens 10, and condenses it on the signal recording layer 100BS of the BD optical disc 100B. . On the other hand, when the light control mirror 17 is switched to the transmission mode, the light beam L1 is transmitted and incident on the objective lens 11, and is condensed on the signal recording layer 100HS of the HD optical disc 100H.

  As a result, like the optical pickup 7, the optical pickup 47 switches the operation mode of the dimming mirror 17 by the control unit 2 and changes the optical path of the light beam L1 according to the disc type discrimination result for the optical disc 100, thereby changing the optical path of the optical beam L1. The optical disk 100 can be irradiated with the light beam L1 via the objective lens 10 or 11 corresponding to 100 types.

  Incidentally, in the optical pickup 47, similarly to the optical pickup 7, the transmittance (about 30%) in the transmission mode of the light control mirror 17 is lower than the reflectance (about 100%) in the reflection mode, and the utilization efficiency of the light beam L1 is improved. Considering the reduction, the HD method and the transmission mode are combined, and the BD method and the reflection mode are combined.

(2-2) Operation and Effect In the above configuration, the control unit 2 of the optical disc apparatus 1 according to the second embodiment determines a predetermined disc when the optical disc 100 is loaded, as in the first embodiment. By processing, the type of the optical disc 100 is determined, and the operation mode of the light control mirror 17 is switched according to the determination result.

  As a result, similarly to the optical pickup 7, the optical pickup 47 can switch the optical path of the light beam L1 by the dimming mirror 17 based on the discrimination result of the optical disc 100 by the control unit 2. Can be irradiated with the light beam L1 via the objective lens 10 and the optical disk 100H for HD via the objective lens 11.

  Further, since the objective lens holder 49 of the optical pickup 47 does not need to be provided with the hole 9A like the objective lens holder 9 (FIG. 3), it can be more rigid than the objective lens holder 9.

  According to the above configuration, the optical pickup 47 of the optical disc device 40 switches the operation mode of the dimming mirror 17 according to the discrimination result of the optical disc 100 by the control unit 2, as in the first embodiment. The optical path of the light beam L1 in the pickup 47 can be changed, the light beam L1 can be irradiated to the BD optical disc 100B via the objective lens 10, and the light beam L1 can be irradiated to the HD optical disc via the objective lens 11. 100H can be irradiated.

(3) Other Embodiments In the above-described embodiment, the objective lens 10 or 11 that condenses the light beam L1 is switched by switching the optical path of the light beam L1 by the dimming mirror 17 in the optical pickup 7. The case of switching to correspond to the BD optical disc 100B or the HD optical disc 100H has been described, but the present invention is not limited to this, and by switching the optical path of the light beam L1 by the dimming mirror 17, any one of them can be selected. The optical disk 100 of the system and the optical disk 100 of another system may be compatible. In this case, an optical component corresponding to the optical disc 100 may be disposed in each optical path.

  In the above-described embodiment, the case where the light beam L1 having a wavelength of 405 [nm] is reflected or transmitted by the dimming mirror 17 is described. However, the present invention is not limited to this, and light of other wavelengths is used. The beam may be transmitted or reflected by the dimming mirror 17.

  In particular, since the light control mirror 17 can transmit or reflect over a wide range of wavelengths as shown in FIG. 6, for example, in addition to BD and HD DVD (registered trademark), CD (Compact Disc) and DVD (Digital Versatile) In addition to the light beam L1 with a wavelength of 405 [nm], an optical pickup with a wavelength of about 780 [nm] corresponding to a CD or a wavelength of about 650 [nm] corresponding to a DVD can be used. The light beam may also be transmitted or reflected.

  Further, in the above-described embodiment, the case where the actuators 8A to 8C are provided so as to sandwich the objective lenses 10 and 11 from both the front and rear sides in the objective lens holder 9 has been described, but the present invention is not limited to this. As shown in FIGS. 9 (A) and 9 (B) in which parts corresponding to those in FIGS. 3 (A) and 3 (B) are given the same reference numerals, the actuator 48 is provided only behind the objective lenses 10 and 11 in the objective lens holder 49. You may make it provide.

  Further, in the first embodiment described above, the light beam L1 is incident on the dimming mirror 17 from a direction parallel to the optical disc 100, and in the second embodiment, the optical disc is incident on the dimming mirror 17. Although the case where the light beam L1 is incident from the normal direction of 100 has been described, the present invention is not limited to this, and the light beam L1 may be incident on the dimming mirror 17 from various other directions. good.

  In this case, by appropriately adjusting the angle of the light beam L1 incident on the light control mirror 17 and the angle of the light control mirror 17 with respect to the optical disc 100, the light beam L1 is perpendicular to the objective lenses 10 and 11, that is, It is only necessary that the optical disk 100 can be guided in a direction parallel to the normal line.

  Further, in the above-described embodiment, when the optical disc 100 is the BD optical disc 100B, the dimming mirror 17 is switched to the reflection mode, and when the optical disc 100 is the HD optical disc 100H, the dimming mirror 17 is changed. Although the case of switching to the transmission mode has been described, the present invention is not limited to this, and when the arrangement of the objective lenses 10 and 11 is changed and the optical disc 100 is the BD optical disc 100B, the light control mirror 17 is set to the transmission mode. When the optical disc 100 is the HD optical disc 100H, the light control mirror 17 may be switched to the reflection mode.

  Further, in the above-described embodiment, the case where the optical disc apparatus 1 can perform both recording and reproduction of information with respect to the optical disc 100 has been described. However, the present invention is not limited to this, and the optical disc 100 is not limited thereto. Only information recording may be performed, or only reproduction of the information may be performed.

  Further, in the above-described embodiment, the case where the optical pickup 7 as the optical pickup is configured by the dimming mirror 17 as the dimming mirror and the control unit 2 as the dimming control unit has been described. However, the present invention is not limited to this, and an optical pickup may be configured by a dimming mirror having various configurations and a dimming control unit.

  Further, in the above-described embodiment, the case where the optical disk device 1 as the optical disk device is configured by the control unit 2 as the determination unit and the dimming control unit and the dimming mirror 17 as the dimming mirror has been described. The present invention is not limited to this, and an optical disc apparatus may be configured by a determination unit having various other configurations, a dimming mirror, and a dimming control unit.

  The optical disc apparatus and optical pickup of the present invention can be used for an optical disc apparatus capable of recording and reproducing a large amount of data, for example.

1 is a schematic diagram illustrating an overall configuration of an optical disc device. It is a basic diagram with which it uses for description of arrangement | positioning of an objective lens. It is a basic diagram which shows the structure of the objective lens holder by 1st Embodiment. It is a basic diagram which shows the structure of the optical pick-up by 1st Embodiment. It is a basic diagram with which it uses for description of reflection and permeation | transmission of the light beam by a light control mirror. It is a basic diagram which shows the optical characteristic of a light control mirror. It is a basic diagram which shows the structural example of the objective-lens holder by radial arrangement | positioning. It is a basic diagram which shows the structural example of the optical pick-up by radial arrangement | positioning. It is a basic diagram which shows the structure of the optical pick-up by 2nd Embodiment. It is a basic diagram which shows the structure of the objective-lens holder by other embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,40 ... Optical disk apparatus, 2 ... Control part, 3 ... Driving part, 7, 47 ... Optical pick-up, 8A-8C ... Actuator, 9, 49 ... Objective lens holder, 10, 11 ... Objective Lens 12... Laser diode 14. Polarizing beam splitter 17. Dimming mirror 18. Upright mirror 100. Optical disk 100 B BD optical disk 100 B 100 H HD optical disk 100 H L1: Light beam.

Claims (8)

An optical pickup that irradiates a first or second optical disc with a light beam emitted from the same light source via a first or second objective lens,
By reflecting the light beam, it is bent in the normal direction of the information recording surface of the optical disc and guided to the first objective lens, and by transmitting the light beam, the information recording surface is reflected by a predetermined rising mirror. A dimming mirror that bends in the normal direction and leads to the second objective lens;
In the dimming mirror, the light beam is reflected when the first optical disc is irradiated with the light beam, and is transmitted through the light beam when the second optical disc is irradiated with the light beam. An optical pickup comprising: a dimming control unit that controls the reflectance of the light beam. The dimming mirror is
By reflecting the light beam substantially parallel to the information recording surface, the light beam is bent in the normal direction of the information recording surface, and transmitted straight through the light beam, and the information recording surface is processed by a predetermined rising mirror. The optical pickup according to claim 1, wherein the optical pickup is bent in a line direction. The light beam is incident on the light control mirror from a tangential direction orthogonal to a radial direction representing a radial direction of the optical disc,
The optical pickup according to claim 1, wherein the first and second objective lenses are arranged along the tangential direction with respect to the optical disc. The first and second objective lenses are attached, and comprise an objective lens holder that swings relative to the optical pickup,
The optical pickup according to claim 1, wherein the objective lens holder is provided with a hole through which only one light beam passes. The lens holder is
Two or more actuators for moving in the focus direction approaching or separating from the first or second optical disc and the tracking direction, which is the radial direction of the first or second optical disc, across the objective lens The optical pickup according to claim 4, wherein the optical pickup is provided at the location. The dimming mirror is
By transmitting the light beam substantially parallel to the normal direction of the information recording surface of the optical disc, the light beam is caused to travel straight, and by reflecting the light beam, the light beam is bent in a direction parallel to the information recording surface, and further, a predetermined rise. The optical pickup according to claim 1, wherein the optical pickup is bent in a normal direction of the information recording surface by a mirror. The dimming mirror is
After the light beam is reflected, the light beam is directly incident on the first objective lens without passing through other optical components, and the light beam is transmitted through and reflected by the rising mirror, and then passes through other optical components. The optical pickup according to claim 1, wherein the optical pickup is directly incident on the second objective lens. An optical disc apparatus for irradiating a first or second optical disc with a light beam emitted from the same light source via a first or second objective lens,
A discriminator for discriminating whether the optical disc is the first optical disc or the second optical disc;
By reflecting the light beam, it is bent in the normal direction of the information recording surface of the optical disc and guided to the first objective lens, and by transmitting the light beam, the information recording is performed by a predetermined rising mirror. A light control mirror that bends in the normal direction of the surface and leads to the second objective lens;
The light beam is reflected when the first optical disk is irradiated with the light beam, and the light beam is irradiated when the second optical disk is irradiated with the light beam according to the determination result by the determination unit. An optical disc apparatus comprising: a dimming control unit that controls a reflectance of the light beam in the dimming mirror so as to transmit light.

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