JP2006120216A - Optical pickup and disk driving device equipped with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure good characteristics for a light receiving element when a plurality of laser beams different in wavelength are used. <P>SOLUTION: A light emitting element 9 having a plurality of emission points 9a to 9c for emitting laser beams different in wavelength according to a type of a disk recording medium 100, and a light receiving element 14 having a light receiving surface for receiving the return light of a laser beam emitted from the light emitting element and reflected on the disk recording medium are provided. The light receiving elements are moved to positions in which the laser beams of wavelengths reflected on the disk recording medium are made incident on the light receiving surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to the technical field of an optical pickup and a disk drive device including the same. More specifically, the present invention relates to a technical field for ensuring good characteristics of a light receiving element when a plurality of laser beams having different wavelengths are used by moving the light receiving element to a position where laser beams having different wavelengths are incident on the light receiving surface.

  2. Description of the Related Art There is a disk drive device that records and reproduces information signals on a disk-shaped recording medium. Such a disk drive device moves in the radial direction of the disk-shaped recording medium mounted on a disk table and moves to the disk-shaped recording medium. And an optical pickup that records or reproduces an information signal by irradiating a laser beam through an objective lens.

  In the optical pickup, optical components such as a light emitting element and a light receiving element are arranged on a moving base that is movable in the radial direction of the disk-shaped recording medium, and laser light emitted from the light-emitting element is recorded on the recording surface of the disk-shaped recording medium. The return light is received by the light receiving element, and the information signal is recorded or reproduced on the disc-shaped recording medium.

  In recent years, disk drive devices have been used for information signals for a plurality of types of disc-shaped recording media having different wavelengths used, such as CD (Compact Disc), DVD (Digital Versatile Disc), BD (Blu-ray Disc), and the like. There are some that can be recorded or played back.

  In the optical pickup provided in such a disk drive device, in consideration of miniaturization and the like, a light emitting element having a plurality of light emitting points for emitting laser beams of different wavelengths toward each disk-shaped recording medium is arranged. There is something that has been.

  In an optical pickup in which a light emitting element having a plurality of light emitting points is arranged, the position of the light emitting point is different and the difference in the refractive index of each optical component causes an optical axis shift between the respective laser beams. Since the points differ, the number of light receiving elements corresponding to laser beams of different wavelengths is arranged, or the optical axis deviation is corrected by arranging an optical axis synthesizing element in the optical path. It corresponds to the difference of the light receiving point.

  In addition, there is an optical axis shift that is corrected by moving or rotating a wedge-shaped glass disposed in the optical path (see, for example, Patent Document 1).

JP-A-6-28687

  However, in the method of arranging the number of light receiving elements corresponding to the laser beams having different wavelengths as described above, the number of optical components such as a light separating element for guiding the laser light to each light receiving element is increased. However, there is a problem that a plurality of light receiving elements for different laser beams are required, the number of parts is increased, and a large space is required for arranging these parts, resulting in an increase in the size of the optical pickup.

  In addition, in the method of arranging the optical axis synthesizing element and the wedge-shaped glass in the optical path, it is necessary to increase the number of parts and to increase the optical path length by arranging these parts. End up.

  Furthermore, the method of arranging the optical axis synthesizing element and the wedge-shaped glass can deal with laser light of two wavelengths, but there is a problem that it becomes difficult to match the optical axes at all wavelengths when the wavelength is three or more. is there.

  On the other hand, in order to cope with the deviation of the light receiving point due to the optical axis deviation described above, a single light receiving element can be provided with a plurality of light receiving surfaces corresponding to the respective wavelengths. There is a problem that the position, the arrangement position of the amplifier circuit, and the like are restricted.

  Accordingly, an optical pickup of the present invention and a disk drive device including the same are intended to overcome the above-described problems and to secure good characteristics of the light receiving element when a plurality of laser beams having different wavelengths are used. .

  In order to solve the above-described problems, an optical pickup of the present invention and a disk drive device including the same are provided with a light emitting element having a plurality of light emitting points that respectively emit laser beams having different wavelengths depending on the type of the disk-shaped recording medium. And a light receiving element having a light receiving surface for receiving the return light of the laser light emitted from the light emitting element and reflected by the disk-shaped recording medium, and each light beam reflected by the disk-shaped recording medium is received by the light receiving surface. The light receiving element is moved to the position where it is incident on the light.

  Therefore, in the optical pickup of the present invention and the disk drive device equipped with the same, the light receiving element is moved according to the position of the light receiving point of each laser beam.

  The optical pickup of the present invention is moved in the radial direction of a disk-shaped recording medium mounted on the disk table, and irradiates the disk-shaped recording medium with a laser beam via an objective lens, and outputs an information signal to the disk-shaped recording medium. An optical pickup that performs recording or reproduction, a light-emitting element having a plurality of light-emitting points that respectively emit laser beams having different wavelengths according to the type of the disk-shaped recording medium, and a disk-shaped recording medium that emits light from the light-emitting element A light receiving element having a light receiving surface for receiving the return light of the reflected laser light, and moving the light receiving element to a position where each wavelength of laser light reflected by the disk-shaped recording medium is incident on the light receiving surface. It is characterized by that.

  Therefore, it is possible to secure good characteristics of the light receiving element while reducing the number of optical components arranged in the optical path of the laser light and shortening the optical path length of the optical system.

  In addition, when multiple light-receiving surfaces corresponding to each wavelength are provided in one light-receiving element, there are no problems such as restrictions on the position of the light-receiving surface and the arrangement position of the amplifier circuit, ensuring good characteristics of the light-receiving element. can do.

  According to the second aspect of the present invention, each movement position of the light receiving element for each laser beam of each wavelength is set in advance, and the light receiving element is moved to each of the movement positions according to the light emission point. Therefore, the movement control of the light receiving element can be easily performed.

  In the invention described in claim 3, the light receiving surface of the light receiving element is divided into a plurality of light receiving areas, the amount of received laser light in each divided light receiving area is detected, and the amount of light received detected in each light receiving area. Since the light receiving element is moved to a position where the position signal of the light receiving element generated based on the above is within a predetermined range, the accuracy of movement control of the light receiving element can be improved.

  In the invention described in claim 4, since the light emitting element is provided with three light emitting points for emitting laser beams having different wavelengths, an optical axis synthesizing element and wedge-shaped glass are arranged to emit light for the three wavelengths. Difficulties when performing axis synthesis are avoided, and good characteristics of the light receiving element can be ensured.

  The disk drive device provided with the optical pickup of the present invention is moved in the radial direction of a disk-shaped recording medium mounted on the disk table and irradiates the disk-shaped recording medium with a laser beam through an objective lens. A disk drive device comprising an optical pickup for recording or reproducing information signals with respect to a recording medium, wherein the optical pickup emits laser beams having different wavelengths according to the type of the disk-shaped recording medium. And a light receiving element having a light receiving surface for receiving the return light of the laser light emitted from the light emitting element and reflected by the disk-shaped recording medium, and each wavelength of the laser reflected by the disk-shaped recording medium The light receiving element is moved to a position where light is incident on the light receiving surface.

  Therefore, it is possible to secure good characteristics of the light receiving element while reducing the number of optical components arranged in the optical path of the laser light and shortening the optical path length of the optical system.

  In addition, when multiple light-receiving surfaces corresponding to each wavelength are provided in one light-receiving element, there are no problems such as restrictions on the position of the light-receiving surface and the arrangement position of the amplifier circuit, ensuring good characteristics of the light-receiving element. can do.

  In the invention described in claim 6, each moving position of the light receiving element for each laser beam of each wavelength is set in advance, and the light receiving element is moved to each moving position according to the light emitting point to emit light. Therefore, the movement control of the light receiving element can be easily performed.

  In the invention described in claim 7, the light receiving surface of the light receiving element is divided into a plurality of light receiving regions, the amount of received laser light in each of the divided light receiving regions is detected, and the amount of light received detected in each light receiving region. Since the light receiving element is moved to a position where the position signal of the light receiving element generated based on the above is within a predetermined range, the accuracy of movement control of the light receiving element can be improved.

  In the invention described in claim 8, since the light emitting element is provided with three light emitting points for emitting laser beams of different wavelengths, an optical axis synthesizing element and wedge-shaped glass are arranged to emit light for the three wavelengths. Difficulties when performing axis synthesis are avoided, and good characteristics of the light receiving element can be ensured.

  The best mode of an optical pickup of the present invention and a disk drive device having the same will be described below with reference to the accompanying drawings.

  The disk drive device 1 is configured by arranging required members and mechanisms in an outer casing 2 (see FIG. 1), and the outer casing 2 has a disk insertion slot (not shown).

  A chassis (not shown) is disposed in the outer casing 2, and the disk table 3 is fixed to the motor shaft of a spindle motor attached to the chassis.

  Parallel guide shafts 4 and 4 are attached to the chassis, and a lead screw 5 that is rotated by a feed motor (not shown) is supported.

  The optical pickup 6 has a moving base 7, required optical components arranged on the moving base 7, and an objective lens driving device 8 arranged on the moving base 7, and is provided at both ends of the moving base 7. The bearing portions 7a and 7b are slidably supported by the guide shafts 4 and 4, respectively. When a nut member (not shown) provided on the moving base 7 is screwed into the lead screw 5 and the lead screw 5 is rotated by the feed motor, the nut member is sent in a direction corresponding to the rotation direction of the lead screw 5, The pickup 6 is moved in the radial direction of the disc-shaped recording medium 100 mounted on the disc table 3.

  In the disk drive device 1 configured as described above, when the disk table 3 is rotated in accordance with the rotation of the spindle motor, the disk-shaped recording medium 100 mounted on the disk table 3 is rotated, and at the same time, the light The pickup 6 is moved in the radial direction of the disc-shaped recording medium 100, and a recording operation or a reproducing operation is performed on the disc-shaped recording medium 100.

  As shown in FIG. 2, the optical pickup 6 includes a light emitting element 9, a beam splitter 11, a collimator lens 12, a rising mirror 13, an objective lens 8a, and a light receiving element 14.

  The light emitting element 9 is a semiconductor laser. From the light emitting element 9, for example, laser light having a wavelength of about 780 nm, about 660 nm, or about 405 nm is the disc-shaped recording medium 100, for example, CD (Compact Disc), DVD (Digital Light is emitted toward Versatile Disc) or BD (Blu-ray Disc).

  As described above, the light emitting element 9 has three light emitting points 9a, 9b, and 9c in order to emit laser beams having three different wavelengths. As shown in FIG. 3, the positions of the light emitting points 9a, 9b, 9c in the light emitting element 9 are orthogonal to the optical axis (Z direction shown in FIG. 3), for example, with the light emitting point 9a as a reference. The light emitting point 9c is spaced 100 μm (distance L1) from the light emitting point 9a in the direction (X direction shown in FIG. 3). Distance L2) Separated. The optical magnification of the optical system provided in the optical pickup 6 is, for example, 2 times, and the light receiving point in the light receiving element 13 emits light from the light emitting point 9b when the laser light emitted from the light emitting point 9a is used as a reference. The laser beam emitted from the light emitting point 9a is positioned at a distance of 200 μm from the light receiving point of the laser light emitted from the light emitting point 9a, and the laser light emitted from the light emitting point 9c is the position of the laser light emitted from the light emitting point 9a. The position is 20 μm apart from the light receiving point in the Y direction.

  The beam splitter 11 reflects the laser light emitted from the light emitting element 9 on the separation surface 11a, guides it to the collimator lens 12, and transmits the return light of the laser light reflected on the disk-shaped recording medium 100 through the separation surface 11a. And has a function of leading to the light receiving element 14.

  The collimator lens 12 has a function of converting the incident laser beam into a parallel beam. Therefore, the laser light incident on the collimator lens 12 via the beam splitter 11 becomes a parallel light flux and enters the objective lens 8 a via the rising mirror 13.

  The raising mirror 13 has a function of reflecting the laser beam and guiding it to the objective lens 8 a or the collimator lens 12.

  The objective lens 8 a has a function of condensing incident laser light on the recording surface of the disk-shaped recording medium 100.

  In the optical pickup 6 configured as described above, when laser light is emitted from the light emitting element 9, the laser light is reflected by the separation surface 11 a of the beam splitter 11 and converted into a parallel light beam by the collimator lens 12. The recording surface of the disk-shaped recording medium 100 mounted on the disk table 3 is irradiated through the objective lens 8a after being raised by the mirror 13. The laser light applied to the recording surface of the disc-shaped recording medium 100 is reflected by the recording surface and is incident on the beam splitter 11 again through the objective lens 8a, the rising mirror 13 and the collimator lens 12 as return light. . The return light incident on the beam splitter 11 passes through the separation surface 11 a of the beam splitter 11 and enters the light receiving element 14. When return light is incident on the light receiving element 14, each signal such as an RF signal is detected, and an information signal is recorded on or reproduced from the disc-shaped recording medium 100, that is, a CD, DVD, or BD.

  As shown in FIG. 4, the light receiving element 14 has a light receiving surface 14a for receiving the return light of the laser beam reflected by the disk-shaped recording medium 100. The light receiving surface 14a has four light receiving areas A, B, and C. , D. For example, it is formed in the shape of a rice field.

  The light receiving element 14 is disposed on a moving mechanism 15 provided on the moving base 7 (see FIG. 5).

  The moving mechanism 15 includes a first base portion 16 and a second base portion 17, and the first base portion 16 having a small outer shape is attached to the second base portion 17 having a large outer shape.

  The light receiving element 14 is disposed on the first base portion 16, and the first base portion 16 is provided with a rack portion 16 a protruding sideways.

  The second base portion 17 is provided with a pair of first bearing projections 17a and 17a and a pair of second bearing projections 17b and 17b. The second base portion 17 is provided with a rack portion 17c protruding sideways.

  The first bearing protrusions 17a and 17a support a first lead screw 19 that is rotated around the axis by the first drive motor 18 and extends in the X direction, and the first lead screw 19 is supported by the first base. The rack portion 16a of the portion 16 is engaged. A first guide shaft 20 extending in the X direction is attached between the second bearing protrusions 17b and 17b, and the first base portion 16 is movably supported by the first guide shaft 20. Accordingly, when the first lead screw 19 is rotated by the first drive motor 18, the rack portion 16 a is sent in a direction corresponding to the rotation direction, and the first base portion 16 is moved to the first guide shaft 20. It is guided and moved in the X direction, and the light receiving element 14 is moved in the X direction along with this movement.

  The moving base 7 of the optical pickup 6 is provided with a pair of third bearing protrusions 7c, 7c and a pair of fourth bearing protrusions 7d, 7d.

  The third bearing protrusions 7c and 7c support a second lead screw 22 that is rotated around the axis by the second drive motor 21 and extends in the Y direction. The second lead screw 22 is a second base. The rack portion 17c of the portion 17 is engaged. A second guide shaft 23 extending in the Y direction is attached between the fourth bearing protrusions 7d and 7d, and the second base portion 17 is movably supported by the second guide shaft 23. Accordingly, when the second lead screw 22 is rotated by the second drive motor 21, the rack portion 17 c is sent in a direction corresponding to the rotation direction, and the second base portion 17 is moved to the second guide shaft 23. It is guided and moved in the Y direction, and the light receiving element 14 is moved in the Y direction along with this movement.

  In the optical pickup 6, when the laser light is emitted from the light emitting points 9a, 9b, 9c, movement control for moving the position of the light receiving element 14 in the XY directions is performed. An example of the movement control in the XY directions will be described with reference to the flowchart shown in FIG.

  In this description, the wavelength of the laser light emitted from the light emitting point 9a is α, the wavelength of the laser light emitted from the light emitting point 9b is β, the wavelength of the laser light emitted from the light emitting point 9c is γ, and the light emitting point. The light receiving point of the laser light emitted from 9a and the light receiving point of the laser light emitted from the light emitting point 9b are separated by 200 μm in the X direction, and light is emitted from the light receiving point of the laser light emitted from the light emitting point 9a and the light emitting point 9c. It is assumed that the received point of the laser beam is 20 μm apart in the Y direction.

  (S1) When laser light is emitted from the light emitting point 9a, the light emitting point 9b, or the light emitting point 9c, movement control in the XY directions is started, and the light receiving element 14 is moved to the initial position by the moving mechanism 15. The initial position is a position to be moved when the laser light is emitted from the light emitting point 9a, and is stored in advance in a storage means such as a memory. Accordingly, in the step (S1), the setting stored in the storage means is read and the light receiving element 14 is moved.

  (S2) When the wavelength of the emitted laser light is β, the process proceeds to (S3), and when the wavelength is not β, the process proceeds to (S4).

  (S3) The light receiving element 14 is moved by 200 μm in the X direction by the moving mechanism 15. This movement distance is set in advance based on the distance between the light emitting points 9a and 9b and the optical magnification of the optical system, and this set value is stored in a storage means such as a memory. Accordingly, in the step (S3), the setting stored in the storage means is read and the light receiving element 14 is moved in the X direction. When the light receiving element 14 is moved in the X direction by 200 μm, the stationary movement control ends.

  (S4) When the wavelength of the emitted laser light is γ, the process proceeds to (S5), and when the wavelength is not γ, the stationary movement control is terminated.

  (S5) The light receiving element 14 is moved by 20 μm in the Y direction by the moving mechanism 15. The setting value is also stored in the storage means for this moving distance as in the case of (S3). In this step (S5), the setting stored in the storage means is read and the light receiving element 14 is read. Is moved in the Y direction. When the light receiving element 14 is moved 20 μm in the Y direction, the stationary movement control is terminated.

  The laser light emitted from each light emitting point 9a, 9b, 9c by the above control is condensed on the light receiving surface 14a of the light receiving element 14 and received. Therefore, it is possible to end the movement control in the X and Y directions at this point, but in the optical pickup 6, depending on the error in the arrangement position of each optical component with respect to the moving base 7 and the processing accuracy of each optical component, There is a possibility that an error may occur in the distance difference between the light receiving points which is set in advance, that is, the distance difference between the light receiving points actually with respect to 200 μm in the X direction or 20 μm in the Y direction. Therefore, in consideration of such an error, the following movement control in the XY directions may be continued.

  When the movement control is continued, the process proceeds to (S6) when the light receiving element 14 is moved 200 μm in the X direction in (S3), and the process proceeds to (S6) when the wavelength is not γ in (S4). When the light receiving element 14 is moved 20 μm in the Y direction in (S5), the process proceeds to (S6).

  (S6) A position detection circuit (not shown) detects the position of the light receiving element 14 in the X and Y directions. This position detection is performed, for example, when the received light amounts of the laser beams in the divided light receiving areas A, B, C, and D of the light receiving surface 14a are Am, Bm, Cm, and Dm, respectively, in the X direction. Is calculated by Px = Am + Dm− (Bm + Cm), and the position signal Py in the Y direction is calculated by Py = Am + Bm− (Cm + Dm).

  (S7) Based on the position signal detected in (S6), the movement direction and movement amount of the light receiving element 14 are calculated. This calculation is performed by the difference between Px value calculated in (S6) and Px = 0 in the X direction, and in the Y direction by the difference between Py value calculated in (S6) and Py = 0. Do.

  (S8) As a result of the calculation in (S7), it is detected whether or not the calculation result for the movement amount is within a predetermined range. If it is detected that the calculation result is within the regulation, the movement control is terminated, and if it is detected that the calculation result is not within the regulation, the process proceeds to (S9).

  (S9) The light receiving element 14 is moved by the moving mechanism 15 based on the calculation result performed in (S7), and subsequently, the steps (S6) to (S8) are performed, and the calculation result regarding the movement amount is determined in advance. The movement control is terminated when it falls within the specified range.

  Further, in the optical pickup 6, in addition to the above-described movement control in the XY direction, movement control in the Z direction, which is a direction orthogonal to the X direction and the Y direction, is also performed. An example of the movement control in the Z direction will be described with reference to the flowchart shown in FIG.

  As described above, in an optical system using laser beams having different wavelengths, when a single light receiving element 14 is used as the optical path of laser beams having different wavelengths, a prism disposed in the optical path, When laser light of an arbitrary wavelength is condensed on the light receiving element 14 due to chromatic aberration generated by an optical component formed of a glass material such as a lens, defocusing is performed on the light receiving element 14 with laser light of other wavelengths. May occur. Therefore, in order to avoid this defocus, the following movement control in the Z direction is required.

  In the description of movement control in the Z direction, the wavelength of the laser light emitted from the light emitting point 9a is α, the wavelength of the laser light emitted from the light emitting point 9b is β, and the wavelength of the laser light emitted from the light emitting point 9c is set. Let γ.

  The movement of the light receiving element 14 in the Z direction is performed by the Z direction moving means. As the Z direction moving means, for example, a piezoelectric element 24 as shown in FIG. 8 is used. The piezoelectric element 24 generates a distortion corresponding to the magnitude of the applied voltage by applying a voltage, and moves the light receiving element 14 in the Z direction. The piezoelectric element 24 serves as the first base portion 16 in the moving mechanism 15. The element 24 may be used. The Z-direction moving means is not limited to the piezoelectric element 24. For example, as with the moving mechanism 15, a mechanical mechanism using a lead screw and a guide shaft can be used.

  (S11) When laser light is emitted from the light emission point 9a, light emission point 9b, or light emission point 9c, movement control in the Z direction is started. If the wavelength of the emitted laser light is α, the process proceeds to (S13). If the wavelength is not α, the process proceeds to (S12).

  (S12) When the wavelength of the emitted laser light is β, the process proceeds to (S14), and when the wavelength is not β, the process proceeds to (S15).

  (S13) The light receiving element 14 is moved from the light emitting point 9a to the initial position Pα when the laser light is emitted. This initial position Pα is obtained by, for example, applying a voltage to the piezoelectric element 24 to detect the applied voltage when the amplitude of the RF signal is maximized, and applying this voltage to the piezoelectric element 24. The position of the light receiving element 14 at the time. Accordingly, at this time, a voltage that is detected and set in advance in a state where laser light is emitted from the light emitting point 9 a is applied to the piezoelectric element 24.

  (S14) An initial voltage when the laser light is emitted from the light emitting point 9b is applied to the piezoelectric element 24 by applying a voltage detected and set in advance in a state where the laser light is emitted from the light emitting point 9b. Move to position Pβ.

  (S15) A voltage detected and set in advance in a state where laser light is emitted from the light emitting point 9c is applied to the piezoelectric element 24, and an initial state when the light receiving element 14 emits laser light from the light emitting point 9c. Move to position Pγ.

  (S16) The optical pickup 6 is moved so that the objective lens 8a is positioned at a position corresponding to a predetermined signal recording area of the disc-shaped recording medium 100.

  (S17) The RF signal for the signal recording area in (S16) is detected, and the amplitude value T1 of the RF signal at the initial position Pα (or Pβ or Pγ) is measured.

  (S18) A predetermined voltage is applied to the piezoelectric element 24 to move the light receiving element 14 by a predetermined amount ΔS in the Z direction with respect to the initial position Pα (or Pβ or Pγ), thereby positioning the light receiving element 14 at position S1.

  (S19) An RF signal for the signal recording area in (S16) is detected, and the amplitude value T2 of the RF signal at position S1 is measured.

  (S20) A predetermined voltage in the direction opposite to the voltage in (S18) is applied to the piezoelectric element 24, and the light receiving element 14 is moved by a predetermined amount −ΔS in the Z direction with respect to the initial position Pα (or Pβ or Pγ). The light receiving element 14 is positioned at the position S2.

  (S21) The RF signal for the signal recording area in (S16) is detected, and the amplitude value T3 of the RF signal in position S2 is measured.

  (S22) Based on the RF signal amplitude values T1, T2, and T3 measured in (S17), (S19), and (S21), the position of the light receiving element 14 when the amplitude of the RF signal is maximized is calculated.

  (S23) A voltage is applied to the piezoelectric element 24 based on the calculated value in (S22), the light receiving element 14 is moved to the position calculated in (S22), and the movement control in the Z direction is terminated.

  In the above, the case where the light receiving element 14 is moved to the position where the amplitude of the RF signal is maximized has been shown as an example. However, the movement position of the light receiving element 14 is determined by measuring the amplitude of the RF signal. For example, a jitter value is measured, and the time when the jitter value is minimized can be determined as the movement position of the light receiving element 14.

  Moreover, although the case where it has the light emitting element 9 which emits a laser beam of 3 wavelengths as an example was shown above, in application of this invention, the number of the laser beams by the difference in wavelength is arbitrary, 2 wavelengths or Four or more wavelengths may be used.

  In the above-described best mode, the case of laser light of three wavelengths has been described. In particular, in the case of three wavelengths, an optical axis synthesizing element or wedge-shaped glass is arranged to synthesize optical axes for all wavelengths. Therefore, when the present invention is applied to laser light having three wavelengths, such difficulty is avoided and good characteristics of the light receiving element 14 can be ensured.

  As described above, in the disk drive device 1, the light receiving element 14 is moved to a position where the laser light of each wavelength reflected by the disk-shaped recording medium 100 is incident on the light receiving surface 14 a of the light receiving element 14. I have to.

  Therefore, it is possible to secure good characteristics of the light receiving element 14 while reducing the number of optical components arranged in the optical path and shortening the optical path length of the optical system.

  In addition, when a plurality of light receiving surfaces corresponding to each wavelength are provided in one light receiving element, there are no problems such as restrictions on the position of the light receiving surface and the arrangement position of the amplifier circuit, and the good characteristics of the light receiving element 14 are obtained. Can be secured.

  Furthermore, as in the steps (S1) to (S5) shown in the flowchart of FIG. 6, the respective moving positions of the light receiving element 14 for each laser beam of each wavelength are set in advance, and light emission points 9a, 9b, Since the light receiving element 14 is moved to each moving position according to 9c, the movement control of the light receiving element 14 can be easily performed.

  In addition, as in the steps (S6) to (S9) shown in the flowchart of FIG. 6, the amount of received laser light in each light receiving area A, B, C, D of the light receiving surface 14a is detected, and each light receiving area is detected. By moving the light receiving element 14 based on the amount of received light detected in A, B, C, and D, it is possible to improve the accuracy of movement control.

  The specific shapes and structures of the respective parts shown in the above-described best mode are merely examples of the implementation of the present invention, and the technical scope of the present invention is limited by these. It should not be interpreted in a general way.

FIG. 2 to FIG. 8 show the best mode for carrying out the present invention, and this figure is a schematic perspective view of a disk drive device. It is a conceptual diagram which shows the structure of an optical pick-up. It is a conceptual diagram which shows the position of the light emission point of a light emitting element. It is a conceptual diagram which shows a light receiving element. It is an expansion perspective view which shows a moving mechanism. It is a flowchart figure which shows the movement control in an XY direction. It is a flowchart figure which shows the movement control in a Z direction. It is an expansion perspective view which shows a piezoelectric element and the light receiving element arrange | positioned at this.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Disc-shaped recording medium, 1 ... Disc drive apparatus, 3 ... Disc table, 6 ... Optical pick-up, 8a ... Objective lens, 9 ... Light emitting element, 9a ... Light emission point, 9b ... Light emission point, 9c ... Light emission point, 14 ... Light receiving element, 14a ... light receiving surface

Claims (8)

Light that is moved in the radial direction of a disk-shaped recording medium mounted on the disk table and that irradiates the disk-shaped recording medium with a laser beam through an objective lens to record or reproduce information signals on the disk-shaped recording medium. A pickup,
A light emitting element having a plurality of light emitting points that respectively emit laser beams having different wavelengths according to the type of the disk-shaped recording medium;
A light receiving element having a light receiving surface for receiving the return light of the laser light emitted from the light emitting element and reflected by the disc-shaped recording medium,
An optical pickup characterized in that a light receiving element is moved to a position where laser light of each wavelength reflected by a disk-shaped recording medium is incident on a light receiving surface. Preset each movement position of the light receiving element for each laser beam of each wavelength,
The optical pickup according to claim 1, wherein the light receiving element is moved to each of the moving positions according to a light emitting point that emits light. The light receiving surface of the light receiving element is divided into a plurality of light receiving areas,
Detect the amount of laser light received in each divided light receiving area,
The optical pickup according to claim 1, wherein the light receiving element is moved to a position where a position signal of the light receiving element generated based on the amount of received light detected in each light receiving region falls within a predetermined range. The optical pickup according to claim 1, wherein the light emitting element is provided with three light emitting points that emit laser beams having different wavelengths. Light that is moved in the radial direction of a disk-shaped recording medium mounted on the disk table and that irradiates the disk-shaped recording medium with a laser beam through an objective lens to record or reproduce information signals on the disk-shaped recording medium. A disk drive device equipped with a pickup,
The above optical pickup
A light emitting element having a plurality of light emitting points that respectively emit laser beams having different wavelengths according to the type of the disk-shaped recording medium;
A light receiving element having a light receiving surface for receiving the return light of the laser light emitted from the light emitting element and reflected by the disc-shaped recording medium,
A disk drive device characterized in that the light receiving element is moved to a position where laser light of each wavelength reflected by the disk-shaped recording medium is incident on the light receiving surface. Preset each movement position of the light receiving element for each laser beam of each wavelength,
6. The disk drive device according to claim 5, wherein the light receiving element is moved to each of the moving positions in accordance with a light emitting point that emits light. The light receiving surface of the light receiving element is divided into a plurality of light receiving areas,
Detect the amount of laser light received in each divided light receiving area,
6. The disk drive device according to claim 5, wherein the light receiving element is moved to a position where a position signal of the light receiving element generated based on the amount of received light detected in each light receiving region falls within a predetermined range. . The disk drive device according to claim 5, wherein the light emitting element is provided with three light emitting points that emit laser beams having different wavelengths.

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