KR100601457B1 - Optical pick-up actuator apparatus - Google Patents

Abstract

The present invention relates to an objective lens switching device of an optical pickup actuator.

According to an aspect of the present invention, there is provided an actuator holder including a lens holder including a plurality of objective lenses, a coil and a magnet for moving the lens holder, and an actuator fixing holder to which a support member for supporting the lens holder is fixed. The actuator fixing holder is formed in contact with the electromagnetic force inducing means so that the objective lens is switchable according to the wavelength of the light source used.

Therefore, according to the present invention, in the BD class high capacity optical information storage device using the next generation blue laser, both CD / DVD level information storage devices can be used in the past.

Description

Actuator device {Optical pick-up actuator apparatus}

1 (a), (b) and (c) are schematic plan and front views of a conventional optical pickup actuator.

2 and 3 show an actuator comprising two lenses for coping with two wavelengths of conventional BD and CD / DVD.

Figure 4 is another embodiment showing an actuator for switching a conventional objective lens

5 is a plan view illustrating vertical switching of a plurality of objective lenses;

6 is a front view illustrating vertical switching of a plurality of objective lenses;

7 is a view showing an actuator switching device according to the present invention.

8 is a view showing a switching structure for sliding the actuator

9 is a view for explaining a driving principle of the linear switching by the principle of the force between the electromagnet 904 and the permanent magnet (901,905).

Fig. 10 is a view showing that the switching drive structure is configured on the symmetrical or one side on the left and right of the actuator.

The present invention relates to an optical pickup actuator capable of interchangeably reproducing a light source from which beams of a plurality of wavelengths are emitted.

Recently, with the development of digital media technology, various contents such as music and movies are pouring out, and recording media for storing the contents are also diversified.

In addition, as digital devices such as notebooks, camcorders, and digital cameras have become lighter and smaller, demands for miniaturization and large capacity of information storage media storing data in the digital devices are increasing. .

As an example of the information recording medium, it is the optical pickup actuator that serves to record / reproduce the information recorded on the optical disc.

The optical pickup actuator moves in the form of a movable coil by a magnetic field of a permanent magnet to move the objective lens to a desired position.

At this time, the movable part is designed to have a desired frequency characteristic by fixing it with a support having rigidity and attenuation characteristic. The movable part translates in two directions perpendicular to each other, focusing and tracking directions, and rotates or twists to reduce an error of an optical signal. The driving should be made without unnecessary vibration such as.

In general, an objective lens driving apparatus is constructed so that a light spot follows the center of a signal track of an optical disk against the surface vibration and eccentricity of the optical disk caused by the condensed light beam from the objective lens.

The objective lens driving apparatus is called an optical pickup actuator, and the objective lens is driven to perform focusing and tracking operations, and to operate in a radial and tangent direction according to the tilt as necessary.

The focusing operation is to drive the objective lens up and down so that the light spot of the light beam from the objective lens falls within the depth of focus in the signal track of the optical disc, and the tracking operation is that the light spot of the light beam from the objective lens detects the signal track of the optical disc. It is to drive left and right to follow the center.

1A, 1B, and 3C are schematic plan and front views of a conventional optical pickup actuator.

A general optical pickup actuator uses a coil and a magnet to move the objective lens by an electric force between the magnet and the current flowing through the coil.

Figure 1 (a) is a schematic view showing a conventional optical pickup actuator, the lens holder (102), the objective lens 101 is mounted in the center and the coil 106,105 coupled to the outer peripheral surface for the focusing and tracking operation ), Magnets 103 and yokes 104 installed on both sides of the lens holder 102, and the lens holder 102 to support the lens holder 102. Upper and lower wire suspensions 107, one end of which is fixed to the upper and lower fixing substrate 108, and a damper provided at one side of the lens holder 102 to which the other end of the wire suspension 107 is fixed. And a damper holder 109 for supporting.

Referring to the accompanying drawings, a conventional optical pickup actuator as described above is as follows.

The objective lens 101 is mounted to the lens holder 102, and the focusing coil 106 is wound around the peripheral surface of the lens holder 102 for focusing, and the tracking is wound in an appropriate direction on each corner surface for tracking. The coil 105 is attached.

In addition, a plurality of yokes 104, which are ferromagnetic materials, protrude from the left and right sides of the lens holder 102 to fix the magnets 103, respectively, and the yoke 104 is a pickup base (not shown). And are integrated by means of integration.

The fixing substrate 108 is coupled to the upper and lower side centers of the lens holder 102, and one end of two parallel wire suspensions 107 is soldered to each of the fixing substrates 108, and the wire suspension 107. The other end of) is fixed to the main substrate through a damper holder 109 provided on one side of the lens holder 102.

Here, a damper (not shown) is coupled to the damper holder 109 so as to have a rigid damping characteristic of the wire suspension 107, and a main substrate (not shown) is coupled to the outside to allow the wire suspension 107 to be coupled to the damper holder 109. Make sure that the other end of is soldered.

The wire suspension 107 floats the lens holder 102 and serves as a relay line for supplying current.

In brief, the operation of the actuator as described above, the tracking coils 105 attached to the lens holder 102 are wound in a proper direction to each other to generate a magnetic flux in a predetermined direction when the current flows, which is fixed Repulsive force and repulsive force are generated by the magnet 103 and the electromagnetic force.

Then, the movement of the lens holder 102 is moved in the tracking direction (before and after) by the repulsive force and the repulsive force, so that the tracking servo for correcting the tracking error is operated.

In addition, the focusing coil 106 is wound in a vertical direction differently from the tracking coil, and the direction of the magnetic flux is generated in the up and down directions when a current flows, so that the coil is electromagnetically acted on the magnetic flux of the fixed magnet 103. By generating a force in the vertical direction 105, the lens holder 102 is moved in the focusing direction (up, down) to operate a focusing servo for correcting it.

The coils 106 and 105 are wound around the outer circumferential surface of the lens holder 102 such that the coil moves together with the lens holder 102 in the focusing and tracking directions. In contrast, the outer circumferential surface of the lens holder 102 The magnet is attached to the moving magnet together with the lens holder is called a moving magnet method.

At this time, the moving method by magnet and coil uses Lorentz force of Fleming's left hand law.

1 (b) and (c) are front views of a conventional two-axis actuator.

On the other hand, as the demand for high-definition video processing increases due to the advancement of consumer preferences, the data storage capacity of optical disks is also required to increase rapidly.

With this demand, a blue laser optical system has been newly developed, and a pickup design applying an exclusive lens development has been made for the optical system design according to the wavelength of the blue laser light source.

However, in order to be compatible with CD (Compact disk) and DVD (Digital Video Disk), which have conventionally used red lasers, it is necessary to develop an objective lens that can cope with all laser wavelengths. Due to this, it is difficult to develop an objective lens that can be accessed at the same time.

Therefore, there is no space for the drive and it is difficult to allow for the cost in order to separate the two optical heads separately for the two systems.

Therefore, a single optical pick-up head including two optical systems can be used to simultaneously use a red laser light and a blue laser light, that is, three standard CDs, DVDs, and BDs (Blue-ray). It is necessary to develop a pickup that can simultaneously use a variety of media.

Conventionally, in order to be able to access various media at the same time (Access), there is an example in which two objective lenses are configured in one actuator and used by a 90 degree switching operation.

2 and 3 show an actuator comprising two lenses to cope with two wavelengths of a conventional BD and a CD / DVD. As shown in FIG. It shows how to rotate the 90 degree objective lens by the magnetic force in the additional magnetic space.

Figure 4 is another embodiment showing a conventional actuator for switching the objective lens.

As shown in the figure, the objective lens switching actuator structure shown in the present invention is the entire actuator (actuator) by the transfer power mechanism 408 located above and below the frame fixing portion of the entire actuator (Disk) The objective lens is configured to linearly move in the track direction to switch the objective lenses 401 and 402.

Operation of the other components of FIG. 4 is substantially the same as that of FIG.

The objective lens 401 for the blue light source (Blue Laser) and the objective lens 402 for the red light source (Red Laser (CD / DVD)) are supported by the lens holder 405, and the driving of the lens holder is a driving coil. 406 and drive magnet 403. The drive magnet is supported by the drive yoke 404.

Wires 409 are fixed to one side and the other side of the lens holder, and the wires are fixed in contact with the actuator fixing holder 407.

In addition, the actuator fixing holder is operated by the linear drive motor 408.

FIG. 5 shows a configuration diagram of an actuator with respect to an upward position of a disc as a recording medium.

The objective lenses 501 and 502 must be configured to move in the vertical direction of the track with respect to the origin position of the disc. For the two objective lenses 501 and 502 to meet these conditions, the objective lenses for the CD / DVD and the BD respectively. The position must be moved so that it can be centered on the optical axis in the track direction.

Therefore, the configuration for transferring and switching the entire actuator (Actuator) in the track direction of the disc by the transfer device of the present invention will be described.

That is, FIG. 5A is a view showing a state in which the actuator fixing holder 507 is operated to the right by the linear driving motor 508 so that the BD objective lens is switched to be at the center of the optical axis.

5B is a view showing a state in which the actuator fixing holder 507 is operated to the left by the linear drive motor 508 so that the objective lens for CD / DVD is switched at the center of the optical axis.

6 shows the objective lens position switching operation seen from the height direction of the actuator.

Initially, the objective lens located at the center of the optical axis can be switched in the track direction of the disc by the actuator transfer device according to the change of the system, and the objective lens suitable for the current system can be switched at the center of the optical axis.

Therefore, it is possible to switch two objective lenses in a desired direction, and one pickup system capable of compatible with both a red laser optical system (CD / DVD) and a blue laser source (BD) is possible.

On the other hand, the actuator used at this time can use a high-speed high-speed wire-type two-axis or three-axis actuator (actuator) in the prior art it is possible to secure the characteristics that can cope with the high speed.

In addition, it is possible to drive the radial direction in the radial direction with the center of two lenses that are configured vertically by configuring a drive system that can be driven in three axes. Compensation is also possible.

6 will be briefly described with reference to FIGS. 4 and 5.

6 (a) is a front view of the state of FIG. 5 (a).

The optical path of the light source output from the light source is incident on the BD objective lens 601 through the reflection mirror 609. For this purpose, the linear drive motor 607 drives the actuator fixing holder 608 to the right. Other magnets 603 and yoke 604 are the same as described above with reference to FIGS. 1 and 4.

6 (b) shows that the optical path of the light source output from the light source is incident on the objective lens 602 for CD / DVD through the reflection mirror 609. To this end, the linear drive motor 607 drives the actuator fixing holder 608 to the left.

However, in the above configuration, the position of the focus drive system and the track drive system is changed according to the magnetic circuit configuration that is changed when the movable part on which the objective lens is mounted is changed, and thus it is difficult to effectively configure it, and the actuator moving part becomes large. It is difficult to improve performance for high speed and high density.

 In addition, since the rotation is about the axis, the movable part guided by the axis has no degree of freedom in the tilt direction, and an actuator configuration for tilt compensation is impossible.

Therefore, in order to satisfy the characteristics that can be exhibited in a conventional lens driving system and to configure two lenses in one actuator, it is necessary to move the entire moving part including the entire magnetic circuit to switch the objective lens on the optical axis. There is.

Therefore, it is necessary to configure the objective lens to effectively switch the two actuators in response to two laser wavelengths by changing the entire actuator in such a system.

The present invention satisfies the characteristics that can be exhibited in a conventional lens driving system. In order to configure two lenses in one actuator, it is necessary to switch the objective lens on the optical axis by moving the entire movable part including the entire magnetic circuit. Suggest.

Therefore, we propose a structure that effectively switches the objective lens to correspond to a plurality of laser wavelengths by switching the entire actuator in each pickup system in one pickup head.

As one means for realizing the above object, a lens holder including a plurality of objective lenses and an actuator fixing holder to which the support member for supporting the lens holder is fixed are integrally moved so that the plurality of objective lenses are used. It is proposed to operate by contacting the actuator holding holder with the electromagnetic force inducing means so as to be switchable according to the wavelength.

The actuator switching device of the present invention for achieving the above object is an actuator to which a lens holder including a plurality of objective lenses, a coil and a magnet for moving the lens holder, and a support member for supporting the lens holder is fixed. In an actuator including a fixed holder, the actuator fixed holder is formed in contact with the electromagnetic force inducing means such that the plurality of objective lenses are switchable in accordance with the wavelength of the light source used.

As an example of the present invention, a plurality of objective lenses are configured in one actuator in a direction perpendicular to the recording medium track to move the actuator around the optical axis to switch to the objective lens corresponding to the light source to be used.

As one example of the present invention, the electromagnetic force inducing means includes a magnet, a means for supporting the magnet and a conductor wound with a conductor.

As one example of the present invention, means for controlling the power polarity is further included to control the operation of the electromagnetic force inducing means.

As an example of the present invention, the force acting on the conductor and the magnet formed in parallel with the conductor is controlled by changing the polarity of the power source applied to the conductor wound on the conductor.

As an example of the present invention, when the conductor and the magnet of the adjacent part are set to the N pole, when the current flows in the clockwise direction (left-> right), the force of the manpower acts on the conductor and the magnet on the left side. do.

As an example of the present invention, when the conductor and the magnet of the adjacent portion are set to the N pole, the repulsive force acts on the conductor and the magnet on the left side when the current flows counterclockwise.

As an example of the present invention, an actuator including a lens holder including a plurality of objective lenses and an actuator fixing holder connected to the lens holder is slid on the base.

As an example of the invention, the magnets are formed in pairs.

As one example of the invention, the electromagnetic force inducing means may be configured on one side or both sides of the actuator fixed holder.

Other objects and features of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the general structure, object, and the related matter of the present invention are summarized.

1. An objective lens in an optical pickup actuator in which a lens holder for supporting a plurality of objective lenses is supported by a wire spring or a leaf spring, so that a single moving part can be configured to enable focusing, tracking, or tilting driving. Actuator switching movement device to switch to match the optical axis according to the system using the principle of magnets and electromagnets (electromagnetic force guide means).

2. The electromagnetic force inducing means forms a conductor wound between the magnet formed in pairs and the magnet.

3. The switching of the electromagnets is made possible by controlling the polarity of the pair of magnets, for example, the polarity of the two magnets and the change of the polarity of the electromagnet (conductor wound around the conductor) in the center.

4. The electromagnetic force inducing means may be located on one side of the actuator holder or may be configured symmetrically on both sides.

5. The drive of the optical pickup actuator is configured in the base and slides.

7 is a view showing the actuator switching device according to the present invention.

Electromagnetic force inducing means 708 is used as a means for driving the optical pickup actuator.

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First, the operation of the optical pickup actuator portion will be described.

A lens holder 705 having a plurality of objective lenses 701 and 702 mounted thereon and a coil 706 for focusing and tracking on an outer circumferential surface thereof, and a magnetic circuit installed at both sides of the lens holder 705. Magnets 703 and yokes 704 and a plurality of wire suspensions 709 having one end fixed to upper and lower portions of the lens holder 705 to support the lens holder 705. And a damper holder 707 provided at one side of the lens holder 705 to support a damper to which the other end of the wire suspension 709 is fixed.

Referring to the accompanying drawings, the optical pickup actuator as described above is as follows.

The objective lenses 701 and 702 are mounted to the lens holder 705, and the focusing coil 706 is wound around the lens holder 705 for focusing, and the tracking coil 710 is wound for tracking.

In addition, a plurality of yokes 704, which are ferromagnetic structures, protrude from the left and right sides of the lens holder 705 to fix the magnets 703, respectively. The yoke 704 is a pickup base (Fig. 8). 810 is integrated with the integration means.

For example, a fixed substrate (not shown) is coupled to a central portion of the lens holder 705, and one end of two parallel wire suspensions 709 is soldered to each fixed substrate, and the other end of the wire suspension is The damper holder 707 provided at one side of the lens holder 705 is fixed to the main substrate.

The operation of the actuator as described above will be described briefly. The tracking coils 710 attached to the lens holder 705 are wound in a proper direction and generate magnetic flux in a predetermined direction when current flows thereto. Repulsive force and repulsive force are generated by the driving magnet 703 and the electromagnetic force.

Then, the movement of the lens holder 705 moves in the tracking direction by the repulsive force and the repulsive force, so that the tracking servo for correcting the tracking error is operated.

In addition, the focusing coil 706 is wound in a vertical direction differently from the tracking coil, and when the current flows, the direction of the magnetic flux is generated in the up and down directions so that the coil acts electromagnetically with the magnetic flux of the fixed magnet 703. By generating a force in the vertical direction (not shown), the lens holder 705 is moved in the focusing direction to operate the focusing servo.

On the other hand, the present invention will be described for the electromagnetic force inducing means for driving the optical pickup actuator for switching the objective lens.

The electromagnetic force inducing means 708 is in contact with the actuator fixing holder 707 such that the plurality of objective lenses 701 and 702 are switchable according to the wavelength of the light source used.

The electromagnetic force inducing means includes a switching magnet 708c in pairs, a means 708d for supporting the magnet, and a conductor 708a wound with a conductive wire 708b.

Also included are means for controlling the application of power (eg 905 in FIG. 9) to control the operation of the electromagnetic force inducing means. The conductor 708a is formed between the switching magnets 708c / 708e in pairs.

The electromagnetic force inducing means 708 configured as described above may be configured on one side or both sides of the actuator fixing holder 707 and the operation is as follows.

The force acting on the conductor and the switching magnets 708c / 708e formed in parallel with the conductor is controlled by changing the polarity (+/−) of the power source applied to the conductor 708b wound on the conductor 708a.

For example, if the polarity of the switching magnet in the conductor and the adjacent part is set to the N pole, when the current flows in the clockwise direction, the force of attraction is applied between the conductor and the switching magnet on the left side, and the current is counterclockwise. In the case of flow through the repelling force between the conductor and the switching magnet on the left side.

The actuator of the present invention slides on the base.

The above description will be further explained with reference to the accompanying drawings.

As a transfer driving device for switching the objective lenses 701 and 702, an electromagnet is formed by a coil wound around an iron core of a conductor so as to be in contact with a part of a fixed holder 707 of a fixing part of an actuator, and both sides corresponding thereto. The switch magnet, which is a permanent magnet, is used to make the reaction force and attraction force switchable to the left and right according to the polarity of the electromagnet.

At this time, the lens holder 705 and the actuator 812 including the portion 813 including the yoke for supporting the fixed holder 707 and the magnet 703 are integrally seated on the pickup base 810 to switch lenses. It is configured as a structure sliding to the slide unit 811 for.

Therefore, the sliding structure can be mechanically guided to linearly move in the direction in which the lens is switched and can be fixed so that there is no fluctuation in the other direction.

The optical pickup actuator does not tolerate slight fluctuation errors after adjustment, so the system configuration is difficult when the drive device has a degree of freedom and causes fluctuations.

Therefore, in the present invention, only the linear motion is possible, and the mechanical guide between the actuator and the pickup base is configured so that the amount of change in the other direction is characterized in that the magnetic yoke of the electromagnet is fixed by the force of the permanent magnet for switching.

8 shows a switching structure for sliding the actuator.

9 illustrates the driving principle of the linear switching by the principle of the force between the electromagnet 904 and the permanent magnet (901,905).

First, Figure 9 (a) is a view showing a basic electromagnetic force inducing means.

9 (b) is an example of the operation of the electromagnetic force inducing means, and when the current flows counterclockwise in the direction as shown in the drawing, the conductor forms an N pole on the left side and an S pole on the right side, respectively. Depending on the polarity of the same pole, one side of the repulsive force (repulsive force) is different, and one side between the poles different from each other, the attraction force acts, the electromagnet moves to the right side where the attraction force acts as shown in Figure 9 (c), the actuator connected to Move it all.

At this time, if the power is turned off, the iron core 903 of the electromagnet acts as a magnetic yoke as shown in FIG. 9 (c), and is fixed to one side of the permanent magnet 901 and is fixed to the optical axis until the type of optical disk is changed. The objective lens can be positioned to perform the desired operation.

On the other hand, if the next disk is changed and it is necessary to switch the lens, as shown in Fig. 9 (d), the power is supplied in the opposite direction of the current in Fig. 9 (b), and this time, the reaction force and the attraction force are generated in opposite directions, respectively. It is driven in the left direction to transfer the entire actuator (Actuator) as shown in Figure 9 (e) to switch the lens.

Likewise, when the switching operation is completed, the power is cut off, and the iron core of the electromagnet becomes a magnetic yoke and is continuously attached to one side of the permanent magnet. Will be.

In this way, the electromagnet moves the actuator while the power is turned on, and only the permanent magnet and the magnetic yoke do not need to turn on the power during the actuator operation to read data from the desired objective lens. Since it can perform a fixed function, it can be effective in terms of power utilization.

FIG. 10 may be configured such that the linear switching drive structure is symmetrical (FIG. 10B) on the left and right sides 1001 and 1002 of the actuator, and also on one side (FIG. 10) in terms of spatial constraints or cost reduction. It is shown that the structure for driving the whole by configuring the drive source 1001 only in 9a).

As described above, the present invention constitutes a plurality of objective lenses in one actuator in a direction perpendicular to the radius of the disk to vertically move the entire actuator around the optical axis by the action of electromagnetic force inducing means to selectively select the wavelengths to be used among the plurality of wavelengths. The present invention relates to a structure capable of switching an objective lens.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents.

It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. For example, it can be applied to any device such as a general home VDR, a desktop drive, and a slim drive.

Therefore, the above description is not limited to the scope of the present invention by the limitation of the claims.

As described above, the present invention can be used interchangeably with both a CD / DVD-class information storage device in a BD-class high capacity optical information storage device using a next-generation blue laser.

In addition, the present invention transfers and switches the entire actuator, which seats two objective lenses, by the driving principle of the electromagnet and the permanent magnet, so that the actuator is seated on the pickup base and the magnetic yoke of the electromagnet is It can be firmly fixed and operate according to the manpower of permanent magnet.

In addition, it is a linear drive structure that can linearly switch the objective lens with each other at a desired position without using a guide sliding between an actuator and a pickup base.

In addition, it is possible to apply a function capable of radial tilt compensation from the central axis of the lens arranged in parallel on the same axis by using a conventional three-axis drive actuator (actuator) while switching between two objective lenses.

Claims (10)

An actuator comprising a lens holder including a plurality of objective lenses, a coil and a magnet for moving the lens holder, and an actuator fixing holder to which a supporting member for supporting the lens holder is fixed. And an electromagnetic force inducing means coupled with the actuator fixing holder so that the plurality of objective lenses are switched according to the wavelength of the light source used. The method of claim 1, And the plurality of objective lenses are configured in one actuator disposed perpendicular to the radial direction of the recording medium to move the actuator to switch to the objective lens corresponding to the light source to be used. The method of claim 1, And said electromagnetic force inducing means comprises a magnet, a means for supporting said magnet and a conductor wound with a conductor. The method of claim 3, wherein And means for controlling power polarity to control operation of the electromagnetic force inducing means. The method of claim 4, wherein And a force acting on the conductor and a magnet arranged in parallel with the conductor by controlling the polarity of the power applied to the conductor wound around the conductor. The method of claim 5, And the magnetic force acts on the conductor and the magnet on the left side when the current flows in the clockwise direction when the magnet of the conductor and the adjacent portion is set to the N pole. The method of claim 5, And the magnets in the adjacent portion of the conductor are set to the N pole, and a repulsive force acts on the conductor and the magnet on the left side when the current flows counterclockwise. The method according to claim 6 or 7, And the actuator including the lens holder including the plurality of objective lenses and the actuator fixing holder connected to the lens holder is slid on a pickup base. The method of claim 3, wherein And the magnets are formed in pairs. The method of claim 1, The electromagnetic force inducing means is an optical pickup actuator device, characterized in that configured on one side or both sides of the actuator fixed holder.

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