JP2013004111A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens holder suitable to an optical pickup device for performing reading operation of a signal recorded in an optical disk.SOLUTION: An objective lens in which a ring-annular flange part is formed at an outer circumferential part of a condenser lens part, and a lens holder 3 in which a mounting hole into which an undersurface of the condenser lens part of the objective lens is inserted is formed and which is supported by a plurality of support wires such that displacement operation with respect to the signal surface of an optical disk in a vertical direction and displacement operation of the optical disk in a radial direction are possible are provided, and the lens holder 3 can be shared by fixing a balancing weight for correcting weight difference of the objective lens to the lens holder 3.

Description

  The present invention relates to an optical pickup apparatus that performs an operation of reading a signal recorded on an optical disc and an operation of recording a signal on the optical disc.

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

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

  As a laser beam for performing an operation for reading a signal recorded on a CD standard optical disk, an infrared light having a wavelength of 780 nm is used, and a laser beam for performing an operation for reading a signal recorded on a DVD standard optical disk. In this case, red light having a wavelength of 650 nm is used.

  The protective layer provided on the upper surface of the signal recording layer in the CD-standard optical disc has a thickness of 1.2 mm, and an aperture of an objective lens used for performing a signal reading operation from the signal recording layer. The number is defined as 0.45. Further, the thickness of the protective layer provided on the upper surface of the signal recording layer in the DVD standard optical disc is 0.6 mm, and the numerical aperture of the objective lens used for performing the signal reading operation from the signal recording layer Is defined as 0.6.

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

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

  Recently, an optical disc apparatus that can use not only the optical discs of the CD standard and the DVD standard but also Blu-ray standard optical discs has been commercialized. An optical pickup device used in such an optical disc apparatus can perform a signal reading operation from a signal recording layer provided in an applicable standard optical disc and a signal recording operation to the signal recording layer. Will be configured.

In such an optical pickup device, it is difficult to irradiate the signal recording layer of the optical disc with the laser light having the above-mentioned wavelength with a single objective lens. Two objective lenses are used: an objective lens and an objective lens that irradiates a Blu-ray standard optical disc with laser light. (See Patent Document 1.)
As is well known, the objective lens incorporated in the optical pickup device is provided with a plurality of support wires so that it can be displaced in the direction perpendicular to the signal surface of the optical disk, that is, the focus direction and the radial direction of the optical disk, that is, the tracking direction. It is fixed on the lens holder.

JP 2008-300009 A

  The lens holder is supported by a support wire so that the displacement operation in the focus direction and the tracking direction can be performed, and the displacement operation in the focus direction and the displacement operation in the tracking direction are well known in the art. It is configured to perform by supplying a drive signal to a focusing coil and a tracking coil mounted on the motor.

  Since the displacement operation in the focus direction and the displacement operation in the tracking direction need to be performed in a well-balanced manner, the weight of the first objective lens and the second objective lens as well as the focusing and tracking coils to be mounted are considered. The lens holder has been designed.

  As the optical disk apparatus, there are a reproduction-only optical disk apparatus that performs only a read operation of a signal recorded on the optical disk and a recording / reproduction optical disk apparatus that can perform a recording operation on the optical disk. A read-only optical pickup device is used for the optical disk device, and a recording / reproducing optical pickup device is used for the recording / reproducing optical disc device.

  Comparing a read-only optical pickup device with a recording / reproducing optical pickup device, the recording / reproducing optical pickup device needs to have a larger laser output than the read-only optical pickup device. The heat generated from will increase. As a result, the temperature of the optical pickup device increases, so that the influence on an optical element such as an objective lens increases.

  Synthetic resin such as plastic is used as the material of the objective lens, but the lens made of synthetic resin has a problem that the optical characteristic changes because the lens expands or contracts depending on the temperature. Accordingly, many glasses having excellent temperature characteristics are used as a material for an objective lens used in an optical pickup device capable of performing a recording operation.

  The glass objective lens has a characteristic that it is heavier than the synthetic resin objective lens in terms of temperature characteristics. Therefore, in the conventional optical pickup device, the lens holder is designed in accordance with the weight of the objective lens to be used. Therefore, the lens holder is designed according to the reproduction-only function and the recording / reproduction function required from the optical disk device. There is a problem that the number of types becomes very large and the manufacturing price becomes high.

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

  The present invention includes an objective lens in which an annular collar is formed on the outer periphery of the condenser lens portion, a mounting hole into which the lower surface of the condenser lens portion of the objective lens is inserted, and a plurality of holes. A lens holder supported by a support wire so as to be able to perform a displacement operation in a direction perpendicular to the signal surface of the optical disk and a displacement operation in the radial direction of the optical disk is provided, and the weight difference of the objective lens is corrected in the lens holder. The lens holder can be shared by fixing the balance weight.

  According to the present invention, the first and second objective lenses each having an annular collar formed on the outer periphery of the condenser lens portion, and the lower surfaces of the condenser lens portions of the first and second objective lenses are respectively provided. First and second mounting holes to be inserted are formed and supported by a plurality of support wires so as to be able to perform a displacement operation in a direction perpendicular to the signal surface of the optical disc and a displacement operation in the radial direction of the optical disc. The lens holder can be shared by fixing a balance weight for correcting a weight difference between at least one of the first objective lens and the second objective lens to the lens holder. It is characterized by.

  The present invention is characterized in that the balance weight has an annular shape.

  The present invention is characterized in that the balance weight is arranged so as to be coaxial with the central axis of the objective lens.

  The present invention is characterized in that the balance weight is made of a non-magnetic material.

  Since the optical pickup device of the present invention corrects the weight difference of the objective lens by fixing the balance weight to the lens holder, the same lens holder can be used even if the weight of the objective lens differs depending on the lens material. Can be used. Therefore, the present invention can share a lens holder incorporated in a read-only optical pickup device or a recording / reproducing optical pickup device, and thus has an advantage that the manufacturing cost can be significantly reduced. .

It is sectional drawing of the principal part which shows the lens holder of this invention. It is a top view of the principal part which shows the lens holder of this invention. It is sectional drawing of the principal part which shows the lens holder of this invention. It is a top view of the principal part which shows the lens holder of this invention. It is a perspective view which shows the weight for balance of this invention.

  Objective lenses with different weights such as synthetic resin objective lenses and glass objective lenses may be used as objective lenses for condensing the laser light emitted from the laser diode onto the signal recording layer provided on the optical disk. Provide a lens holder that can.

  1 and 3 are cross-sectional views showing the main part of the lens holder constituting the optical pickup device of the present invention, and FIGS. 2 and 4 are plan views showing the main part of the lens holder constituting the optical pickup device of the present invention. FIG. 5 is a perspective view showing an embodiment of a balance weight used in the optical pickup device of the present invention.

  In the figure, reference numeral 1 denotes a first objective lens for condensing a laser beam for reproducing a signal recorded on, for example, a CD standard and DVD standard optical disc on a signal recording layer of the optical disc. An annular collar 1b is provided on the outer periphery of the condenser lens portion 1a. Reference numeral 2 denotes a second objective lens for condensing a laser beam for performing a recording / reproducing operation of a signal recorded on a Blu-ray standard optical disc on a signal recording layer of the optical disc. An annular flange 2b is provided on the outer periphery of the portion 2a.

  In such a configuration, since the first objective lens 1 is a lens that performs a laser beam condensing operation to perform a reproducing operation, the first objective lens 1 is made of synthetic resin, and the second objective lens 2 is a laser beam that performs a recording / reproducing operation. Since it is a lens that performs the condensing operation, it is made of glass.

  Reference numeral 3 denotes one end fixed to a printed wiring board provided on a base (not shown) constituting the optical pickup device and a plurality of support wires 4 made of a conductor perpendicular to the signal surface of the optical disk. The lens holder is supported so as to be able to be displaced in a focusing direction which is a direction and a tracking direction which is a radial direction of the optical disc, and a lower surface of a condensing lens portion 1a constituting the first objective lens 1 is inserted therein. The 1st mounting hole 5 and the 2nd mounting hole 6 in which the lower surface of the condensing lens part 2a which comprises the said 2nd objective lens 2 is inserted are formed.

  Further, the first mounting hole 5 and the second mounting hole 6 formed in the lens holder 3 are an optical axis central axis of the first objective lens 1 and an optical axis of the second objective lens 2 inserted into the mounting holes. A straight line (shown by a broken line A) connecting the central axes is provided so as to coincide with the radial direction of the optical disc.

  Reference numeral 7 denotes an annular mounting groove formed around the second mounting hole 6 formed in the lens holder 3 so that the lower surface of the condenser lens portion 2a of the second objective lens 2 can be inserted. An annular balance weight 8 as shown in FIG. 5 is bonded and fixed. The balance weight 8 is bonded and fixed to the mounting groove 7 of the lens holder 3 when a synthetic resin objective lens is used as the second objective lens 2, and is made of a nonmagnetic material such as phosphor bronze. Manufactured.

  In such a configuration, the lens holder 3 is mounted with a driving coil such as a focusing coil for displacing the lens holder 3 in the focus direction and a tracking coil for displacing the lens holder 3 in the tracking direction, and the drive supplied through the support wire 4. The lens holder 3, that is, the first objective lens 1 and the second objective lens 2 are in the focus direction by the cooperation of the magnetic flux excited by the signal and the magnetic flux generated by the magnet fixed to the base constituting the optical pickup device. And is configured to be displaced in the tracking direction. Such focusing coil and tracking coil are mounted on the lens holder 3 by a well-known technique, and the description thereof is omitted.

  As described above, the first mounting hole 5 to which the first objective lens 1 is fixed, the second mounting hole 6 to which the second objective lens 2 is fixed, and the balance weight 8 are bonded and fixed to the lens holder 3. A mounting groove 7 is formed. Further, as described above, a driving coil such as a focusing coil or a tracking coil is mounted on the lens holder 3, but the balance is maintained when the first objective lens 1 made of synthetic resin and the second objective lens 2 made of glass are fixed. It is designed to have good characteristics.

  When a synthetic resin objective lens is used as the second objective lens 2, the balance characteristic 8 is configured to be good by bonding and fixing the balance weight 8 to the attachment groove 7. In other words, the weight of the balance weight 8 is designed to correct the weight difference between the weight of the synthetic resin objective lens and the weight of the glass objective lens.

  As described above, the lens holder 3 according to the optical pickup device of the present invention is configured. Next, the first objective lens 1, the second objective lens 2 and the balance weight 8 are fixed to the lens holder 3. The operation will be described.

  1 and 2 show a case where a synthetic resin objective lens is used as the first objective lens 1 and a glass objective lens is used as the second objective lens 2, and the balance weight 8 has a mounting groove. 7 is not adhesively fixed. That is, in the optical pickup device having such a configuration, the optical disk on which the signal reading operation is performed by the laser beam condensed by the first objective lens 1 is subjected only to the reproduction operation, and is condensed by the second objective lens 2. An optical disc on which a signal reading operation is performed by a laser beam to be used is configured to be used when a recording operation is performed as well as a reproduction.

  In such an optical pickup device, when the signal recording operation is performed with the laser light condensed by the second objective lens 2, the temperature of the second objective lens 2 increases as the laser output increases. This is a configuration when a glass objective lens having excellent temperature characteristics is used as the second objective lens 2.

  When a synthetic resin objective lens is used as the first objective lens 1 and a glass objective lens is used as the second objective lens 2, the balance weight 8 is not used as described above. The lens holder 3 is designed to have a good balance characteristic.

  As described above, the lens holder 3 when the glass objective lens is used as the second objective lens 2 is configured. Next, the configuration when the synthetic resin objective lens is used as the second objective lens 2 is described. explain.

  3 and 4 show a case where a synthetic resin objective lens is used as the first objective lens 1 and a synthetic resin objective lens is used as the second objective lens 2. In such a case, balance is achieved. The weight 8 is bonded and fixed to the mounting groove 7 as shown. That is, in the optical pickup device having such a configuration, the optical disk on which the signal reading operation is performed by the laser beam condensed by the first objective lens 1 is subjected only to the reproduction operation, and is condensed by the second objective lens 2. An optical disc on which a signal reading operation is performed by the laser beam is configured to perform only a reproducing operation.

  In such an optical pickup device, the temperature of the second objective lens 2 does not increase when only the signal reproduction operation is performed with the laser light condensed by the second objective lens 2. This is a configuration in the case of using a synthetic resin objective lens excellent in mass production.

  When a synthetic resin objective lens is used as the first objective lens 1 and a synthetic resin objective lens is used as the second objective lens 2, the balance weight 8 is used as described above. And the balance characteristic of the lens holder 3 can be made favorable similarly to the case where the glass objective lens shown in FIG. 2 is used.

  As described above, even if an objective lens made of a material having a different weight is used as the second objective lens 2 such as glass having excellent temperature characteristics or a synthetic resin that can be produced at low cost, the balance weight 8 is used. Since the weight difference between the lenses is corrected by the above, the same lens holder 3 can be shared. Therefore, if the lens holder according to the present invention is used, the same lens holder can be used as the lens holder of the optical pickup device having different functions, so that the optical pickup device can be manufactured at low cost.

  In the present embodiment, the case where the lens holder 3 is configured to be mounted with two objective lenses, the first objective lens 1 and the second objective lens 2, has been described. A similar effect can be obtained when the present invention is applied to a lens holder in which only a lens is mounted.

  Further, in this embodiment, the case where the glass objective lens and the synthetic resin objective lens are used only on the second objective lens 2 side has been described. However, the glass objective lens and the synthetic objective are used on the first objective lens 1 side. It can also be carried out when using a resin objective lens. That is, in such a case, an annular mounting groove is formed around the first mounting hole 5 to which the first objective lens 1 is fixed.

  In this embodiment, the balance weight 8 is provided on the objective lens mounting surface side of the lens holder 3, that is, on the upper side in FIG. 1, but may be provided on the opposite side, that is, on the lower side. Further, as the material of the balance weight 8, a non-magnetic material that is not affected by the magnetic flux generated by the magnet or each coil is used.

  In this embodiment, the case where the glass objective lens is used as the objective lens for condensing the recording laser beam has been described. However, the glass objective lens is used for the purpose of condensing the laser beam for reproduction only. It can also be implemented when used as a lens.

  The present invention is effective for an optical pickup device that performs a reading operation and a recording operation of a signal recorded on a plurality of optical discs of different standards such as an optical disc of a CD standard, a DVD standard, and a Blu-ray standard. The present invention can also be implemented in an optical pickup device that performs a reading operation and a recording operation of a signal recorded on a standard optical disc.

DESCRIPTION OF SYMBOLS 1 1st objective lens 2 2nd objective lens 3 Lens holder 5 1st attachment hole 6 2nd attachment hole 7 Attachment groove 8 Balance weight

Claims (5)

An objective lens in which an annular collar is formed on the outer peripheral portion of the condenser lens portion, a mounting hole into which the lower surface of the condenser lens portion of the objective lens is inserted, and a plurality of support wires An optical pickup device including a lens holder supported so as to be capable of displacement in a direction perpendicular to a signal surface of an optical disc and displacement in a radial direction of the optical disc. An optical pickup device characterized in that a lens holder can be shared by fixing a balance weight to be corrected. First and second objective lenses each having an annular flange formed on the outer periphery of the condenser lens portion, and first and second surfaces into which the lower surfaces of the condenser lens portions of the first and second objective lenses are inserted, respectively. A lens holder having a second mounting hole and supported by a plurality of support wires so as to be able to perform a displacement operation in a direction perpendicular to the signal surface of the optical disc and a displacement operation in the radial direction of the optical disc. In this optical pickup device, the lens holder can be shared by fixing a balance weight for correcting the weight difference between at least one of the first objective lens and the second objective lens to the lens holder. An optical pickup device characterized by the above. 3. The optical pickup device according to claim 1, wherein the balance weight has an annular shape. 4. The optical pickup device according to claim 3, wherein the balance weight is arranged so as to be coaxial with the central axis of the objective lens. 4. The optical pickup device according to claim 3, wherein the balance weight is made of a non-magnetic material.

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