JP2006164401A - Objective lens drive apparatus, and optical pickup apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective lens drive apparatus, and an optical pickup apparatus in which the configuration of a drive mechanism is extremely simple, there is no risk of heating, further, low vibration, low power consumption, and low noise can be achieved. <P>SOLUTION: A polymer actuator 108 is used as a drive source. One end of the polymer actuator 108 is fixed to an actuator supporting substrate 109 of a housing 101, and the other end is fixed to a lens holder 107 supporting an objective lens 106. The polymer actuator 108 is curved in the focus direction and the tracking direction by applying potential to a conductive polymer layer of a focus drive area and a tracking drive area. Thereby, the objective lens 106 is driven in the focus direction and the tracking direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an objective lens driving device and an optical pickup device.

An optical pickup device mounted on a CD player, a DVD player, or the like is equipped with an objective lens actuator that drives the objective lens in a focus direction and a tracking direction. As such an objective lens actuator, those utilizing an electromagnetic driving force between a coil and a magnet are widely used.
Japanese Patent Laid-Open No. 2003-16660

  However, according to such an actuator, a drive mechanism such as a coil and a magnet is required in addition to the suspension wire that elastically supports the objective lens, and there is a problem that the configuration becomes complicated. In addition, vibration or the like may adversely affect the performance of the optical pickup device.

Therefore, the present invention provides an objective lens driving device and a pickup device that have an extremely simple driving means, are easy to reduce in size and thickness, are not easily affected by vibration, and can realize low power consumption and low noise. The issue is to provide.

  In view of the above problems, the present invention has the following features.

  According to a first aspect of the present invention, in the objective lens driving device, the objective lens driving device includes a support member that supports the objective lens so that the objective lens can be displaced in a focus direction and a tracking direction. A structure is provided in which the shape is displaced in the focus direction and the tracking direction by entering and exiting the material.

  In the objective lens driving device according to claim 1, the support member has a columnar shape as described in claim 2, and a cross-sectional region perpendicular to the longitudinal direction is formed by entering and exiting the dopant ions. The structure can be divided into a region of the structure that is displaced in the focus direction and a region of the structure that is displaced in the tracking direction by the entry and exit of the dopant ions.

  At this time, as described in claim 3, the structure can be formed on the surface of the core wire having a columnar shape, divided into a region displaced in the focus direction and a region displaced in the tracking direction. .

  More specifically, as described in claim 4, the structure includes a common electrode formed on a surface of the core wire, a divided electrode formed by being divided into the regions, and the common electrode. A conductive polymer material layer formed between the divided electrodes and a solid electrolyte layer for allowing dopant ions to enter and exit the conductive polymer material layer can be formed.

  In the objective lens driving device having the above-described configuration, as described in claim 5, the support member is configured by a plurality of support members that support the objective lens so as to be displaceable in a focus direction and a tracking direction, and The structure member that displaces each support member in the focus direction and the structure region that displaces in the tracking direction are applied to the focus drive direction and the tracking drive direction of the objective lens by applying a servo voltage, respectively. It can be configured to be arranged so as to be displaced.

  The invention according to claim 6 is an optical pickup device including an actuator for driving the beam converging body in the focus direction and the tracking direction, and includes a support member that supports the beam converging body so as to be displaceable in the focus direction and the tracking direction, The support member has a structure whose shape is displaced in the focus direction and the tracking direction when dopant ions enter and exit the conductive polymer material by applying a servo voltage.

  Such an optical pickup device can have the same configuration as that shown in the second to fifth aspects. These are indicated in claims 7 to 10, respectively.

The “support member” in the present invention is indicated as “polymer actuator 108” in the embodiment. Further, the “beam converging body” in the present invention is indicated as “objective lens 106” in the embodiment. In addition to this, such a “beam converging body” can also be realized by a relay lens, a follower lens, or a member in which a follower lens and a light emitting unit are integrated. The following embodiment exemplifies one embodiment of the present invention, and does not limit the meaning of the term of the present invention or each component.

  According to the present invention, since the shape of the support member itself is displaced by applying a servo voltage, actuators such as coils and magnets are not required, and the configuration of the objective lens driving device and the optical pickup device is simple and simple. It can be.

In addition, since the structure in the invention hardly generates heat or mechanical vibration, there is no problem that the characteristics of the optical pickup device are deteriorated by heat or vibration from the driving means. Further, this structure has low power consumption and generates almost no noise during driving, so that the power consumption and noise of the apparatus can be reduced.

  Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of the optical pickup device.
As shown in the figure, an optical pickup device includes a housing 101 for mounting an optical system, a semiconductor laser 102 that emits laser light of a predetermined wavelength, a beam splitter 103 that splits the laser light from the semiconductor laser 102, and a beam splitter. A collimator lens 104 that converts light that has passed through 103 into parallel light, a mirror 105 that raises the laser light that has passed through the collimator lens 104 upward, and an objective lens 106 that converges the laser light raised by the mirror 105. I have.

  Also, a lens holder 107 that holds the objective lens 106, four polymer actuators 108 that cantilever-support the lens holder 107 so as to be displaceable in the focus direction and the tracking direction, and an unsupported side end of the polymer actuator 108 are fixed. The actuator support substrate 109 is provided. With the configuration of the actuator, the objective lens 106 is supported so as to be displaceable in the focus direction and the tracking direction. The structure and operation of the polymer actuator 108 will be described in detail later.

  In addition, the optical pickup device converges the laser light reflected by the beam splitter 103, receives the laser light converged by the converging lens 110, and reproduces an RF signal, a focus error signal, a tracking error signal, and the like. The photodetector 111 which outputs the electric signal for producing | generating is provided.

  Such an optical pickup device is mounted on a chassis in an optical disc device so that the housing 101 is supported by a pair of guide shafts 201 and 202 so as to be movable in the disc radial direction.

  FIG. 2 shows the configuration of the actuator.

  As illustrated, the polymer actuator 108 has an elongated cylindrical structure. Also, as shown in the cross-sectional view in the figure, a structure having a polymer material layer is formed around the core wire, and this structure has a region (focus drive area) displaced in the focus direction and a tracking direction. It is divided into a region to be displaced (tracking drive area). The focus drive area and the tracking drive area occupy arc regions having the same dimensions. Each polymer actuator 108 is configured such that the facing direction of the pair of focus driving areas matches the focus driving direction of the objective lens 106 and the facing direction of the pair of tracking driving areas matches the tracking driving direction of the objective lens 106. Has been placed.

  FIG. 3 shows a cross-sectional structure of the polymer actuator 108. 2A is a cross-sectional view when the polymer actuator 108 is cut in a direction orthogonal to the longitudinal direction, and FIG. 3B is a cross-sectional view taken along the line AA ′ in FIG. is there.

  As shown in FIG. 2A, the polymer actuator 108 includes a common electrode layer (electrode layer B), conductive polymer layers A and B, a solid electrolyte layer A, a divided electrode layer A, C is laminated. Furthermore, an insulating layer is formed on the outer surface.

  In general, macromolecules are produced by polymerizing monomer molecules together to form long chains of molecules. Here, when the monomer molecule has a property of transferring electrons between adjacent molecules at the time of polymerization, the polymer after generation becomes a conductive polymer. That is, the polymer itself has conductivity. This conductivity is close to that of a semiconductor.

  Typical monomer molecules suitable for the formation of a conductive polymer include pyrrole and thiophene. When these are polymerized, it becomes polypyrrole or polythiophene.

  By incorporating various ions called dopants during the polymerization, the conductive polymer itself has p-type or n-type characteristics depending on the polarity of the ionic species. In this state, if the conductive polymer is immersed in the electrolyte solution, and the potential is applied with the electrolyte solution side negative and the conductive polymer layer side positive, for example, if the incorporated dopant ions have positive polarity The dopant ions go out into the electrolyte solution. In addition, when a potential opposite to this is applied, dopant ions are taken into the conductive polymer. In addition, when dopant ion has negative polarity, the behavior contrary to this is shown.

  Here, the amount of ions entering and exiting the conductive polymer is determined by the applied potential difference. That is, when a predetermined potential is applied, the amount of ions taken in the conductive polymer (several or charge amount) is uniquely determined so as to be in an electrochemically equilibrium state with it. Note that when the application of a potential is interrupted in a state where ions are taken in (or out), ions do not substantially enter and exit between the conductive polymer and the electrolyte solution.

  By the way, when dopant ions are taken in at the time of polymerization as described above, an ion pocket secured by the dopant ions (having a polarity opposite to that of the dopant ions) is formed in the conductive polymer material itself. The Here, there are various sizes of dopant ions incorporated into the conductive polymer. By appropriately selecting this size, it is possible to control the physical penetration rate into the conductive polymer.

  When ions are taken in by applying a potential to the conductive polymer material, the volume of the conductive polymer material itself increases. Conversely, the volume decreases as ions exit. Note that “conductive polymer layer A” and “conductive polymer layer B” shown in FIG. 3 are materials having pockets of dopant ions of opposite polarity. Therefore, when the same potential is applied to these two materials, one increases in volume and the other decreases in volume. For this reason, when these two material layers are arranged so as to face each other with the core wire interposed therebetween, a polymer actuator is configured to bend in a direction in which the volume is reduced.

  The polymer actuator 108 shown in FIG. 3 is configured using the characteristics of the conductive polymer. In the polymer actuator 108 shown in the figure, a solid electrolyte layer A is used instead of the electrolyte solution described above.

  In the polymer actuator 108, when the same potential is applied to the conductive polymer layers A and B in the focus drive area or the tracking drive area as shown in FIGS. The layer increases in volume and the other decreases in volume. As a result, the entire polymer actuator 108 is deformed (curved) into an arc shape.

  Here, when the conductive polymer layers A and B are in the focus drive area, the polymer actuator 108 bends in the focus direction. When the conductive polymer layers A and B are in the tracking drive area, the polymer actuator 108 bends in the tracking direction. In this case, since one end of the polymer actuator 108 is fixed to the actuator support substrate 109, the free end on the lens holder 107 side is displaced in the focus direction and the tracking direction. Therefore, the objective lens 106 is displaced in the focus direction and the tracking direction with this displacement.

  Therefore, the objective lens 106 can be driven in the focus direction and the tracking direction by applying a servo signal to the polymer actuator 108 as shown in FIGS.

  FIG. 5 shows a manufacturing process of the polymer actuator having the above structure.

  First, in the step (a) of the figure, the electrode layer B is formed on the surface of the core wire by vacuum deposition or the like. Next, in the step of FIG. 5B, after half of the coating surface of the electrode layer B is masked in the longitudinal direction of the core wire, the conductive polymer layer B is formed on the other half of the coating surface. In this step, referring to FIG. 6, after the core wire is fitted into a semicircular mold (step b-1), a resin is coated on the core wire to form a mask (step b-2). Then, the core wire with the mask formed on one side is removed from the mold (step b-3), and the conductive polymer layer B is formed on the surface by electrolytic polymerization (step b-4). At this time, if the mask is an insulator, the conductive polymer layer B is not polymerized on the mask portion. Thereafter, the mask and the conductive polymer layer B formed on the mask surface are removed.

  Returning to FIG. 5, in step (c), the conductive polymer layer A is formed after masking in the longitudinal direction of the core wire so as to cover the conductive polymer layer B. Thereafter, the mask and the conductive polymer layer A formed on the mask surface are removed. In this step, referring to FIG. 7, after the core wire portion where the conductive polymer layer B is not formed is fitted into a semicircular section mold (step c-1), resin or the like is applied on the core wire. Solidify and form a mask (step c-2), remove the core wire with the mask formed on one side from the mold (step c-3), and further form the conductive polymer layer A on the surface by electrolytic polymerization (step) c-4). At this time, as in the case of FIG. 6, if the mask is an insulator, the conductive polymer layer A is not polymerized on the mask portion. Thereafter, the mask and the conductive polymer layer A formed on the mask surface are removed.

  Returning to FIG. 5, next, in the step of FIG. 5D, the solid electrolyte layer A is uniformly formed on the surfaces of the conductive polymer layers A and B. Further, in the step shown in FIG. 5E, electrode layers A and C are formed on the surface of the solid electrolyte layer A in four parts. The electrode layers A and C are formed by forming a uniform electrode layer on the surface of the solid electrolyte layer A and then cutting the cut in the longitudinal direction of the core wire (laser cutting, etc.) so as to be divided into four. Can do. Alternatively, vapor deposition may be formed by sputtering or the like while masking the parting line portion. Thereafter, an insulating layer is formed on the outermost peripheral surface with a resin or the like.

  According to the above-described embodiment, the objective lens driving mechanism can have a very simple configuration, and the driving mechanism can be reduced in size and thickness. In addition, since the conductive polymer actuator does not generate heat or vibration during driving in the focus direction and tracking direction, there is no problem that the characteristics of the optical pickup device deteriorate due to heat or vibration. Furthermore, since the conductive polymer actuator has low power consumption and little noise, the power consumption and noise of the optical pickup device can be reduced.

  As mentioned above, although embodiment which concerns on this invention was described, it cannot be overemphasized that this invention is not limited to this embodiment, and various changes are possible.

  For example, in the above-described embodiment, the dopant ions are de-injected into the conductive polymer layer by disposing the solid electrolyte layer, but the dopant is obtained by immersing the conductive polymer layer in the electrolyte solution. It is also possible to de-implant ions into the conductive polymer layer.

  In addition, the lamination state and the number of laminations of the conductive polymer layer and the solid electrolyte layer are not limited to those in the above embodiment, and any other one can be used as long as the polymer actuator can be displaced in the focus direction and the tracking direction. The stacking state and the number of stacks may be adopted.

  Furthermore, in the above embodiment, the common electrode (electrode layer B) is formed on the surface of the core wire, but the core wire may be formed of a conductive material and used as the common electrode. In addition, although the cross section of the polymer actuator is circular, other cross sectional shapes may be used.

  The embodiment of the present invention can be appropriately modified in various ways within the scope of the technical idea shown in the claims.

The figure which shows the structure of the optical pick-up apparatus which concerns on embodiment. The figure which shows the structure of the actuator which concerns on embodiment The figure which shows the structure of the polymer actuator which concerns on embodiment The figure which shows the drive state of the polymer actuator which concerns on embodiment The figure which shows the manufacturing process of the polymer actuator which concerns on embodiment The figure which shows the manufacturing process of the polymer actuator which concerns on embodiment The figure which shows the manufacturing process of the polymer actuator which concerns on embodiment

Explanation of symbols

106 Objective lens 108 Polymer actuator for focus

Claims (10)

A support member that supports the objective lens so as to be displaceable in a focus direction and a tracking direction is provided. The support member has a shape that is formed by the dopant ions entering and exiting the conductive polymer material by applying a servo voltage. Comprising a structure that is displaced in a direction,
An objective lens driving device. In claim 1,
The support member has a columnar shape, and a cross-sectional area perpendicular to the longitudinal direction is displaced in the focus direction by the entrance and exit of the dopant ions, and the tracking by the entrance and exit of the dopant ions. Divided into regions of structures that are displaced in the direction,
An objective lens driving device. In claim 2,
The structure is formed on the surface of the core wire having a columnar shape, being divided into a region displaced in the focus direction and a region displaced in the tracking direction.
An objective lens driving device. In claim 3,
The structure includes a common electrode formed on a surface of the core wire, a divided electrode formed by being divided into the regions, a conductive polymer material layer formed between the common electrode and the divided electrode, and Comprising a solid electrolyte layer for allowing dopant ions to enter and exit the conductive polymer material layer;
An objective lens driving device. In any of claims 2 to 4,
The support member includes a plurality of support members that support the objective lens so as to be displaceable in a focus direction and a tracking direction. Each support member includes a region of a structure that is displaced in the focus direction, and the tracking direction. The region of the structure that is displaced in the direction is arranged so as to be displaced in the focus driving direction and the tracking driving direction of the objective lens by applying a servo voltage, respectively.
An objective lens driving device. In an optical pickup device having an actuator for driving a beam converging body in a focus direction and a tracking direction,
A support member that supports the beam converging body so as to be displaceable in a focus direction and a tracking direction is provided, and the support member has a shape that is formed by the dopant ions entering and exiting the conductive polymer material by applying a servo voltage. Comprising a structure that is displaced in the tracking direction;
An optical pickup device characterized by that. In claim 6,
The support member has a columnar shape, and a cross-sectional area perpendicular to the longitudinal direction is displaced in the focus direction by the entrance and exit of the dopant ions, and the tracking by the entrance and exit of the dopant ions. Divided into regions of structures that are displaced in the direction,
An optical pickup device characterized by that. In claim 7,
The structure is formed on the surface of the core wire having a columnar shape, being divided into a region displaced in the focus direction and a region displaced in the tracking direction.
An optical pickup device characterized by that. In claim 8,
The structure includes a common electrode formed on a surface of the core wire, a divided electrode formed by being divided into the regions, a conductive polymer material layer formed between the common electrode and the divided electrode, and A solid electrolyte layer that allows dopant ions to enter and exit the conductive polymer material layer;
An optical pickup device characterized by that. In any of claims 7 to 9,
The support member includes a plurality of support members that support the beam converging body so as to be displaceable in a focus direction and a tracking direction. Each support member includes a region of the structure that is displaced in the focus direction, and the tracking. The region of the structure that is displaced in the direction is arranged so as to be displaced in the focus driving direction and the tracking driving direction of the beam converging body, respectively, by applying a servo voltage.
An optical pickup device characterized by that.

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