JP2004318973A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device which can cope with a plurality of kinds of media without restricting the shape of a device by realizing switching of a plurality of optical lenses in a compact and simple structure. <P>SOLUTION: This device is an optical disk device provided with a pickup mechanism 3 in which an optical system guiding a laser beam and converging the laser beam on a recording plane of an optical disk to record or reproduce information is provided, and a track moving means which can move the pickup mechanism 3 in the radial direction of the optical disk. The pickup mechanism 3 is provided with a holding base 3A holding a plurality of objective lenses 10A, 10B of which the operation distance are different and a plurality of lens driving means 11A, 11B performing position compensation of an objective lens, and sliding mechanisms 32, 37, 37 moving this holding base 3A in parallel, further, when the objective lens 10A having a longer operation distance is arranged at a position of the pickup, the lens driving means 11B is operated and a position of the objective lens 10B having a shorter operation distance is lowered. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk device for recording or reproducing information on or from an optical disk, and more particularly, to a technique particularly useful when used in an optical disk device capable of supporting a plurality of types of optical disks.
[0002]
[Prior art]
At present, a plurality of types of optical disk media such as a CD (compact disk), a DVD (digital versatile disk), and an optical disk capable of recording and reproducing a large amount of data using a blue-violet laser have been put to practical use.
When recording or reproducing information on or from these optical discs, it is necessary to use a laser beam having a wavelength corresponding to the type of the medium. Further, for CDs and DVDs, an objective lens having a numerical aperture NA of “0.65”, a blue-violet In the case of a laser medium, it is necessary to use an objective lens having a numerical aperture according to the type of the medium, such as an objective lens having a numerical aperture NA of "0.85".
[0003]
Therefore, in order to make a single optical disc device correspond to a plurality of types of media, a plurality of semiconductor lasers having different output wavelengths and a plurality of objective lenses having different numerical apertures are mounted in the device, and these are set according to the media. It is necessary to switch and use. For example, Patent Literature 1 discloses a technology that can support a plurality of media by switching and using a plurality of objective lenses.
[0004]
As a conventional configuration for switching a plurality of objective lenses, as shown in FIG. 6, two sets each having an optical system for guiding laser light to a pickup position and objective lenses 82A and 82B for condensing laser light on a recording surface are provided. And two sets of track moving mechanisms for moving these two sets of pickup mechanisms 80A and 80B in the radial directions H1 and H2 of the optical disk D0, respectively.
[0005]
[Patent Document 1]
JP-A-9-270141
[Problems to be solved by the invention]
However, the switching structure shown in FIG. 6 has a problem in that two paths must be secured in the apparatus to move the pickup mechanisms 80A and 80B, and the required space increases. In general, the shape of an optical disc device mounted on a personal computer is standardized, and it is difficult to adopt the switching structure of FIG. 6 in such a device in terms of securing space. The structure shown in FIG. 6 is disadvantageous in reducing the size of the disk drive even if it is not used.
[0007]
It is an object of the present invention to realize switching of a plurality of objective lenses with a compact and simple structure, whereby it is possible to cope with a plurality of types of media without limiting the shape of the device and to manufacture at low cost. To provide an optical disk device capable of performing the following.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an optical system for guiding a laser beam for recording or reproducing information, a pickup mechanism provided with an objective lens for condensing the laser beam on a recording surface of an optical disc, and the pickup In an optical disc apparatus including a track moving unit that enables the mechanism to move in a radial direction of the optical disc and a control unit that controls each driving unit, the pickup mechanism includes a plurality of objective lenses having different working distances, A plurality of lens driving means for respectively correcting the positions of the plurality of objective lenses; a holding base for holding the plurality of objective lenses and the plurality of lens driving means; and a plurality of the objective lenses to a pickup position at which laser light is emitted. And a slide mechanism for moving the holding base in parallel so that the arrangement can be switched. The lens driving means for moving the objective lens having a short working distance away from the optical disc at least at the time of recording or reproducing information, when an objective lens having a long working distance among the plurality of objective lenses is disposed at the pickup position; Is controlled.
[0009]
According to such a means, the switching of the objective lens can be realized by a simple configuration in which a plurality of objective lenses are slid, and the configuration for moving the pickup mechanism in the track direction is only one. No space is required. On the other hand, if such a simple configuration is adopted, there is a problem that an objective lens having a short working distance may come into contact with an optical disc when an objective lens having a long working distance is used due to a difference in working distance of each objective lens. According to the present invention, such a problem can be avoided in such a case by operating the position correcting lens driving means to move the objective lens having a short working distance away from the optical disc.
[0010]
Specifically, it is preferable that the plurality of objective lenses are arranged so that the distances from the disk surface of the optical disk are different in accordance with the respective working distances in a state where the plurality of lens driving units are not operating. This allows each objective lens to be used with its initial position at an optimum height, thereby reducing the load on the lens driving means for correcting the position of the objective lens.
[0011]
Further, it is preferable that the slide mechanism is configured to move the holding base in parallel with the disk surface of the optical disk. Thereby, the holding base and its sliding mechanism can also adopt a simple configuration.
[0012]
Further, the pickup mechanism may be provided with slide driving means for driving the slide mechanism. Thereby, the switching of the objective lens can be performed quickly.
[0013]
Also, a slide drive unit for driving the slide mechanism is provided separately from the pickup mechanism, and the slide drive unit and the slide mechanism are engaged when the pickup mechanism is moved to a predetermined position by the track moving unit. In addition, the holding base may be configured to be slidable by the slide driving unit. This makes it possible to reduce the size of the pickup mechanism moved in the radial direction with respect to the optical disc.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view showing an example of an optical pickup mechanism and its peripheral configuration in an optical disk device according to an embodiment of the present invention. FIG. 2 shows a state in which a frame and a holding base of the optical pickup mechanism are separated. FIG.
[0015]
The optical disk device of this embodiment includes, for example, three semiconductor lasers having different output wavelengths (other semiconductor lasers 20A are omitted in FIG. 1) and two objective lenses 10A having different numerical apertures. By using these semiconductor lasers and objective lenses by switching between them, it is also compatible with optical disks for blue-violet lasers that record and reproduce large amounts of information using blue-violet lasers in addition to CDs and DVDs. An optical disk device.
[0016]
The optical disc apparatus includes a pickup mechanism 3 having an optical system for guiding laser light along a predetermined path for recording or reproducing information, such as a semiconductor laser 20A... And objective lenses 10A and 10B, and a central portion of the optical disc. A spindle 2 which is fixedly driven to rotate, screw shafts 4 and 4 as track moving means for moving the pickup mechanism 3 in the radial direction of the optical disk in accordance with a recording or reproducing position of information, a driving motor (not shown), and an objective lens A lens switching drive unit (slide driving means) 5 for switching between 10A and 10B and a tray mechanism for taking an optical disk in and out of the apparatus are provided.
[0017]
Although not shown, the optical disc apparatus includes a drive control of an optical system for controlling output of a laser beam and minute position correction of an objective lens, data processing of recording data and reproduction data, insertion and removal of a tray of an optical disc, There is provided a control circuit (control means) for controlling each drive unit, such as rotational drive control of the spindle 2, drive control for switching the objective lens, and drive control of the pickup mechanism 3 in the track direction.
[0018]
As shown in FIGS. 1 and 2, the optical pickup mechanism 3 includes two objective lenses 10A and 10B and two sets of lens actuators (lens driving means) 11A that respectively perform minute position correction of the objective lenses 10A and 10B. , 11B, a holding base 3A for holding the objective lenses 10A, 10B and the lens actuators 11A, 11B, a frame 3B on which the holding base 3A is slidably movable, and various types mounted on the frame 3B. And the like.
[0019]
The two objective lenses 10A and 10B have, for example, numerical apertures of “NA 0.65” and “NA 0.85” and a working distance (Working Distance) representing a distance from the lens upper surface to the focal position of “1.5 mm”. "And" 0.1 mm ".
[0020]
The lens actuator 11A holds the objective lens 10A in a lens holder 111 fixed in a state where it can be minutely displaced by a plurality of wires 112, and is arranged to face a coil (not shown) provided on a side surface of the lens holder 111. The lens holder 111 is displaced by the force generated by the magnet 113 or the force generated by a magnet (not shown) provided on the lens holder 111 and a coil disposed opposite to the magnet 113 to finely correct the position of the objective lens 10B. Is what you do.
[0021]
The driving directions of the objective lens 10B by the lens actuator 11B are three axial directions: a focal direction of the light of the objective lens 10B, the same tracking direction as the radial direction of the optical disk, and a tilt angle direction corresponding to the tilt of the optical disk in the radial direction. . Various proposals have been made for these driving methods, and various driving methods can be applied to the lens actuator.
The other lens actuator 11B has the same configuration.
[0022]
The optical system elements mounted on the frame 3B include a semiconductor laser 20A, a collimator lens, a condenser lens, a beam splitter, a laser diode, and the like. Although these elements are not described in detail, they output laser light to a pickup position where one of the objective lenses 10A and 10B is disposed, guide the laser light, extract reflected light of an optical disk to detect intensity, and perform laser irradiation. A part of the output light is fed back for feedback control to keep the light output level constant, or a part of the incident light or the reflected light is extracted for correcting the position of the objective lenses 10A and 10B in three axial directions. It is used for
[0023]
As shown in FIG. 2, the frame 3B of the pickup mechanism 3 has an emission hole 31 for outputting a laser beam to the objective lens, slide shafts (slide mechanism) 32, 32 for slidingly moving the holding base 3A, A stopper 33 for positioning the holding base 3A and bearings 35 for receiving the screw shafts 4, 4 are provided. The stopper 33 is formed, for example, by fixing a spherical engaging projection 33b to one end of a leaf spring 33a, and fixing the other end of the leaf spring 33a to the frame 3B with a screw 33c.
[0024]
On the other hand, the holding base 3A is engaged with through holes 36A, 36B provided below the two objective lenses 10A, 10B and through which laser light passes, and the gear 5b of the lens switching drive unit 5 (FIG. 1). A rack portion 39 is provided, and a bearing (slide mechanism) 37 for receiving the slide shafts 32, 32, and an engagement groove 38 for engaging with the engagement protrusion 33b of the stopper 33 are provided on the lower surface of the holding base 3A. , 38 are provided.
[0025]
The slide shafts 32 are installed in parallel with the disk surface of the optical disk, so that the holding base is slid in parallel with the disk surface. Further, at a position where the through holes 36A, 36B of the holding base 3A overlap the emission hole 31 of the frame 3B, the engaging projections 33b of the stopper 33 and the engaging grooves 38, 38 are engaged.
[0026]
The lens switching drive unit 5 includes, for example, a drive motor 5a and gears 5b and 5c. When the pickup mechanism 3 is moved along the screw shafts 4 and 4 to the outermost position of the optical disk, the lens switching drive unit 5 moves the holding base 3A. The rack 39 and the gear 5b are fixed at a position where they mesh with each other.
[0027]
FIG. 3 is a front view illustrating the arrangement relationship of the objective lenses held by the holding base. In the figure, the lens holders 111 and 111B show cross sections including the optical axes of the objective lenses 10A and 10B, and the objective lenses 10A and 10B show the front shapes as they are. Further, in the same drawing, the wires 112, magnets 113, etc. of the lens actuators 11A, 11B are omitted.
[0028]
As shown in FIG. 3, the two lens holders 111 are installed at the same height in a state where the lens actuators 11A and 11B are not operated. The lens holder 111 is provided with a through hole 111a for passing laser light at the center thereof and an insertion hole 111b for inserting a lens or the like at an upper portion thereof.
[0029]
The objective lens 10A having a long working distance is directly inserted and fixed in, for example, the insertion hole 111b, while the objective lens 10B having a short working distance is inserted and fixed in the insertion hole 111b via the sub-lens holder 111B. ing.
[0030]
As a result, the objective lenses 10A and 10B are arranged such that the objective lens 10B having a shorter working distance is closer to the optical disc D0 than the objective lens 10A having a longer working distance in accordance with the respective working distances. Then, the lens actuators 11A and 11B can perform the position correction process with the state close to the non-operation state as the origin, so that the operation load is small and the best operation characteristics are derived. The distance between the objective lenses 10A and 10B and the optical disk D0 does not need to be the same as the respective working distances. For example, the objective lens 10B having a short working distance has a margin and is arranged at a position slightly separated from the working distance. You may do it.
[0031]
Further, by holding the objective lens 10B via the sub-lens holder 111B as described above, the two sets of lens actuators 11A and 11B can have exactly the same configuration, so that the cost of parts can be reduced. Has become.
[0032]
4A and 4B are front views illustrating a state in which the pickup mechanism is operating. FIG. 4A illustrates a state using an objective lens with a short working distance, and FIG. 4B illustrates a state using an objective lens with a long working distance. It is in the state of being.
[0033]
According to the optical disk device of this embodiment, when the optical disk D0 for blue-violet laser is inserted into the disk tray and detected, the screw shafts 4 and 4 are driven to rotate by the control circuit, and the pickup mechanism 3 rotates the optical disk. The lens is moved to the lens switching home position at the outermost position. Then, in this state, the lens switching drive unit 5 is driven to move the holding base 3A in parallel, and as shown in FIG. 4A, the objective lens 10B having a short working distance is moved to the exit hole 31 through which the laser light is emitted. Placed in the position. Further, in this state, the stopper 33 acts to fix the position of the holding base 3A.
[0034]
When the switching of the arrangement of the objective lens 10B is completed, the pickup mechanism 3 moves in the track direction along the screw shafts 4 and 4 under the control of the control circuit, and moves the objective lens 10B to a predetermined track of the optical disc. The laser beam is condensed to record or reproduce information.
[0035]
On the other hand, when the optical disk D1 of CD or DVD is inserted into the disk tray, the screw shafts 4 and 4 are rotationally driven by the control circuit, and the pickup mechanism 3 is moved to the home position at the outermost peripheral position of the optical disk. Then, in this state, the lens switching drive unit 5 is driven to move the holding base 3A in parallel, and the objective lens 10A having a long working distance is disposed at the position of the emission hole 31 from which the laser light is emitted. Further, in this state, the stopper 33 acts to fix the position of the holding base 3A.
[0036]
At the stage where the objective lens 10A with a long working distance is arranged at the position of the exit hole 31, as shown in FIG. 3, the objective lens 10B with a short working distance is arranged close to the optical disc D1. The disk surface of the optical disk is not a strict plane, but has a slight inclination in the radial direction or has a wobbling surface. Then, the magnitude of the inclination or the runout may be larger than the working distance (for example, 0.1 mm) of the objective lens 10B. When the objective lens 10B is used, the lens actuator 11B performs position correction so as to follow these tilts and surface shakes, so that the objective lens 10B does not touch the disk surface. When the lens 10B is not used, the position is not corrected, so that the objective lens 10B may touch the disk surface as it is.
[0037]
Therefore, according to the optical disk device of this embodiment, as shown in FIG. 4B, when the arrangement of the objective lens 10A having a long working distance is switched to the pickup position, the control circuit controls the objective lens having a short working distance. The lens actuator 11B of the lens 10B is operated, and the objective lens 10B is driven to move away from the disk surface of the optical disk.
[0038]
Then, in this state, the pickup mechanism 3 moves in the track direction along the screw shafts 4 and 4, and the laser beam is focused on a predetermined track of the optical disc by the objective lens 10A to record or reproduce information. Is
[0039]
As described above, according to the optical disk device of this embodiment, the switching of the objective lenses 10A and 10B can be realized with a simple configuration in which the holding base 3A is slid, and the pickup mechanism 3 is mounted on the track. Since only one configuration is required to move in the direction, there is an effect that the required space can be reduced as compared with the case where two systems of track moving mechanisms are provided. In addition, the problem of contact between the disk surface and the objective lens 10B having a short working distance, which may occur in such a simple configuration, can be avoided by driving the lens actuator 11B.
[0040]
Further, a lens switching drive unit 5 for slidingly driving the holding base 3A is provided separately from the pickup mechanism 3 moved in the track direction, and the holding base 3A is moved when the pickup mechanism 3 is moved to the home position for lens switching. Since the slide drive is possible, the pickup mechanism 3 can be made compact.
[0041]
It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible. FIG. 5 shows another configuration example in which the holding base 3A is slidably driven. For example, as shown in the figure, in the configuration in which the holding base 3A is slidably driven, a plunger 51a pushes a lever 53 provided rotatably about a rotation shaft 53b and a projection 53c provided on the lever 53. It can also be constituted by a solenoid actuator 51 for rotating and driving the lever 53 and a spring 54 for applying a force in a direction opposite to the moving direction by the lever 53.
[0042]
According to such a configuration, when the solenoid actuator 51 operates, the lever 53 rotates, and the contact portion 53a pushes the side surface of the holding base 3A to move rightward, and the driving of the solenoid actuator 51 stops. Thus, the holding base 3A is returned to the left by the force of the spring 54. When such a configuration is adopted, it is preferable that the lever 53, the solenoid actuator 51, and the spring 54 are provided on the frame 3B of the pickup mechanism 3 and move in the track direction together with the pickup mechanism 3.
[0043]
In addition, various methods can be adopted as a method of slidingly driving the holding base 3A, such as a configuration in which the holding base 3A is slidably driven by rotation using a screw shaft. Further, the configuration for holding the holding base 3A so as to be slidable is not limited to the configuration of the slide shaft 32 and the bearing 37 that moves along the slide shaft 32. For example, various systems such as a configuration using a rail can be adopted.
[0044]
In the above embodiment, the lens switching drive unit 5 is fixed near the lens switching home position. However, this lens switching drive unit 5 is installed on the frame 3B of the pickup mechanism 3 and It may be configured to move in the track direction together with. Thus, an effect is obtained that the switching of the objective lenses 10A and 10B can be executed quickly regardless of the arrangement of the pickup mechanism 3.
[0045]
Other details specifically shown in the above embodiment, such as the type of optical disk, the number of objective lenses, the numerical aperture and working distance of the objective lens, and the type of optical system mounted on the frame of the pickup mechanism, are examples. Needless to say, it can be changed as appropriate without departing from the spirit of the present invention.
[0046]
【The invention's effect】
As described above, according to the present invention, switching of the objective lens can be realized with a simple configuration in which a plurality of objective lenses are slid, and only one configuration for moving the pickup mechanism in the track direction is required. Therefore, there is an effect that it can be realized in a small space.
[0047]
Also, due to the difference in the working distance of each objective lens, there is a problem that the objective lens with a short working distance may come into contact with the optical disc when using an objective lens with a long working distance. This problem can be avoided by driving the means to move the objective lens having a short working distance away from the optical disk.
[0048]
Further, in a state where the lens driving means is not driven, the objective lens having a short working distance is arranged closer to the optical disc than the objective lens having a long working distance in correspondence with the working distance of each objective lens, so that each objective lens is disposed. The lens can be used with the initial position at an optimum height, which has the effect that the lens driving means can be used within an appropriate operating range.
[0049]
Further, by adopting a configuration in which the slide mechanism of the holding base is moved in parallel with the disk surface of the optical disk, there is an effect that the configuration and arrangement of the objective lens and the lens driving means can be simplified.
[0050]
Also, by providing the pickup mechanism with slide driving means for driving the holding base to slide, there is an effect that the objective lens can be quickly switched.
[0051]
Further, a slide driving means for slidingly driving the holding base is provided separately from the pickup mechanism, and the holding base can be slidably driven by the slide driving means when the pickup mechanism is moved to a predetermined position. There is an effect that the mechanism can be made compact.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a drive system of an optical pickup in an optical disc device according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a state where a frame body and a holding base of the optical pickup mechanism are separated.
FIG. 3 is a front view partially showing a cross-sectional view for explaining an arrangement relationship of an objective lens held by a holding base.
4A and 4B are front views illustrating a state in which a pickup mechanism is operating. FIG. 4A illustrates a state using an objective lens with a short working distance, and FIG. 4B illustrates a state using an objective lens with a long working distance. It is in the state of being.
FIG. 5 is a perspective view showing a modified example of a drive mechanism for slidingly driving a holding base.
FIG. 6 is a diagram illustrating a structure that can be used by switching between two objective lenses in a conventional optical disc device.
[Explanation of symbols]
2 Spindle 3 Pickup mechanism 3A Holding base 3B Frame 4 Screw shaft 5 Lens switching drive units 10A, 10B Objective lenses 11A, 11B Lens actuator 32 Slide shaft 33 Stopper 35 Bearing 37 Bearing 38 Engagement groove 39 Rack part 111 Lens holder 111B Sub Lens holder

Claims (6)

An optical system for guiding laser light along a predetermined path for recording or reproducing information, and a pickup mechanism provided with an objective lens for condensing the laser light on a recording surface of the optical disc; An optical disc device comprising: a track moving unit for moving in a direction; and a control unit for controlling each drive unit.
In the pickup mechanism, two objective lenses having different working distances from each other and arranged at different distances from the disk surface of the optical disc corresponding to the respective working distances, and correcting the positions of these objective lenses, respectively. Two sets of lens driving means, a holding base for holding the two objective lenses and the two sets of lens driving means, and a parallel movement of the holding base in parallel with the disk surface of the optical disc to move the plurality of objective lenses A slide mechanism is provided, which is capable of switching the arrangement to a pickup position from which laser light is emitted,
The control means is configured to move the objective lens having a short working distance away from the optical disc at least at the time of recording or reproducing information, when the objective lens having a long working distance among the plurality of objective lenses is disposed at the pickup position. While being configured to control the lens driving means,
Slide drive means for driving the slide mechanism is provided separately from the pickup mechanism,
When the pickup mechanism is moved to a predetermined position by the track moving means, the slide drive means and the slide mechanism are engaged, and the holding base can be slidably driven by the slide drive means. An optical disk device characterized by the following. A pickup mechanism provided with an optical system for guiding laser light for recording or reproducing information and an objective lens for condensing the laser light on the recording surface of the optical disc, and enabling the pickup mechanism to move in the radial direction of the optical disc In an optical disc device including a track moving unit and a control unit that controls each driving unit,
The pickup mechanism includes a plurality of objective lenses having different working distances, a plurality of lens driving units for respectively correcting the positions of the plurality of objective lenses, and a holding unit for holding the plurality of objective lenses and the plurality of lens driving units. A base, and a slide mechanism for moving the holding base in parallel so that the arrangement of the plurality of objective lenses can be respectively switched to a pickup position where the laser beam is emitted,
The control means is configured to, when the objective lens having a long working distance among the plurality of objective lenses is disposed at the pickup position, at least at the time of recording or reproducing information, to move the objective lens having a short working distance away from the optical disc. An optical disk device configured to control the lens driving unit. The plurality of objective lenses are arranged so that the distance from the disk surface of the optical disk is different from each other in accordance with each working distance in a state where the plurality of lens driving units are not operating. The optical disk device according to claim 2. 4. The optical disk device according to claim 2, wherein the slide mechanism is configured to move the holding base in parallel with a disk surface of the optical disk. 5. The optical disk device according to claim 2, wherein a slide drive unit that drives the slide mechanism is provided in the pickup mechanism. Slide drive means for driving the slide mechanism is provided separately from the pickup mechanism,
The slide drive means and the slide mechanism are engaged when the pickup mechanism is moved to a predetermined position by the track moving means, and the holding base is slidably driven by the slide drive means. 5. The optical disk device according to claim 2, wherein:

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