JPH09120559A - Optical head device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To switch plural objective lenses answering to plural kinds of optical disks and to improve responsiveness and reliability by simply forming its structure. SOLUTION: Plural objective lenses 12, 13 are provided successively on a lens holder 11, and the lens holder 11 is supported by elastic members 10 with a holder support member 5. The holder support member 5 supported by a holder slide mechanism 18 is slidden by a lens switch mechanism 19. Then, one piece between plural objective lenses 12, 13 is arranged on an optical path of a laser optical system 14 selectively. The lens holder 11 is formed simply and lightly by preventing the mechanism switching plural objective lenses 12, 13 from loading on the lens holder 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head device for forming an image of a laser beam emitted from a laser optical system on an optical disc by an objective lens.

[0002]

2. Description of the Related Art At present, an optical disc recorder for recording information on an optical disc, an optical disc player for reproducing information on the optical disc, and the like have been realized. Such an optical disk device has a turntable that rotationally drives the optical disk, and the optical head device irradiates the rotationally driven optical disk with laser light. This optical head device
It has a laser optical system and an objective lens, and images the laser light emitted from the laser optical system on the track of the optical disc by the objective lens.

At this time, the track of the rotationally driven optical disk fluctuates in the focusing direction which is the optical axis direction and the tracking direction which is orthogonal to this and is parallel to the surface of the disk.
In order to deal with this, the optical head device connects a lens holder on which an objective lens is mounted to a holder support member with an elastic member, and elastically supports the objective lens so as to be displaceable in the tracking direction and the focusing direction. There is. Then, by displacing the objective lens in accordance with the displacement of the track of the optical disk, the laser spot is made to follow the track so that information can be reproduced well.

[0004]

In the above optical head device, it is possible to form a laser spot on a track of an optical disk.

However, there are various types of such optical discs, for example, CD (Compact Disk) and DVD (Digi
However, the spot diameter and the depth of focus required for recording and reproducing are different from those of the tal video disk) because they have the same size and the like but have different laminated structures and track widths. On the other hand, a DVD player is required to be able to reproduce a CD, and in order to realize this, it is necessary for one optical head device to generate two kinds of light condensing characteristics.

For example, an optical head device has been developed in which the objective lens is formed of optical glass to have a double focus.
This is because the structure of the objective lens is complicated and the productivity is not good.
In addition, the CD can be rotated by the holder rotation mechanism provided on the lens holder.
And an optical head device for supporting two objective lenses for DVD and DVD, and moving these objective lenses to selectively arrange one of them on the optical path have been announced. However, in this case, it is necessary to mount a holder rotation mechanism for switching between two objective lenses, a drive source, and the like on the lens holder, and the weight of this lens holder increases, and the responsiveness of tracking and focusing deteriorates.

Further, in the product announced with the above-mentioned structure, the lens holder is formed with an arc-shaped opening hole through which the two objective lenses are moved. It is expected that it will be difficult to move. Further, in such a structure, since a gap is required between the objective lens and the aperture hole, it is difficult to hold the objective lens with high precision, and resonance occurs in the objective lens, which deteriorates the frequency characteristic. In order to prevent this, it is conceivable to reduce the gap between the objective lens and the aperture, but this causes the above-mentioned problem of dust to become noticeable, and malfunctions will occur even when expansion and contraction due to temperature changes.

[0008]

According to the first aspect of the present invention,
An objective lens facing the optical disc is mounted on a lens holder, and this lens holder is elastically supported by a resilient member to be elastically supported so as to be displaceable in the tracking direction and the focusing direction, and emitted from a laser optical system. In an optical head device for forming an image of light on the optical disc by the objective lens, a plurality of objective lenses are continuously provided in the lens holder in a direction orthogonal to a focusing direction, and the holder supporting member is slidably supported in this direction. A holder slide mechanism is provided, and a lens switching mechanism that slides the holder support member to selectively dispose one of the objective lenses on the optical path of the laser optical system is provided. Therefore, when the holder slide mechanism slides the holder support member that supports the lens holder, the objective lens that images the laser light emitted from the laser optical system on the optical disk is switched. For this reason, it is not necessary to form one objective lens with a double focus using optical glass, and it is not necessary to mount a mechanism for switching the objective lens on the lens holder.

According to a second aspect of the present invention, in the first aspect of the invention, a damper member for absorbing vibration is provided in the holder slide mechanism, and the holder supporting member is made of a magnetic material. Therefore, the vibration generated in the holder slide mechanism is absorbed by the damper member, and the holder support member and the holder slide mechanism are brought into close contact with each other by the magnetic attractive force.

According to a third aspect of the present invention, an objective lens facing the optical disk is mounted on a lens holder, and the lens holder is connected to a holder supporting member by an elastic member so as to be elastically displaced in a tracking direction and a focusing direction. In an optical head device that supports and images a laser beam emitted from a laser optical system on the optical disc by the objective lens, a holder that rotatably supports the holder support member in an axial direction parallel to the tangential direction. A rotation mechanism is provided, a plurality of objective lenses are arranged on an arc centered on the axis of the holder rotation mechanism, and the holder support member is rotated to move one of the plurality of objective lenses to the laser optical system. A lens switching mechanism is provided which is selectively arranged on the optical path. Therefore, when the holder rotation mechanism rotates the holder support member that supports the lens holder, the objective lens that images the laser light emitted from the laser optical system on the optical disk is switched. For this reason, it is not necessary to form one objective lens with a double focus using optical glass, and it is not necessary to mount a mechanism for switching the objective lens on the lens holder.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the holder rotating mechanism has a support shaft that passes through the holder support member and faces the lens holder. The support shaft and the lens holder A magnet was arranged on one of the end faces facing each other and a coil was arranged on the other. Therefore, since the magnetic force generated by this coil acts on the magnet, the magnetic force causes the lens holder to be displaced with respect to the support shaft in the focusing direction and the tracking direction.

According to a fifth aspect of the present invention, in the third aspect of the invention, two objective lenses are mounted on the lens holder in the directions in which the optical axes are orthogonal to each other, and two types of coils that excite in these directions are provided. Two sets of connection terminals attached to the lens holder and individually connected to the two types of coils are provided on the holder support member, and the tracking electrode for outputting the driving power for tracking the objective lens and the driving power for focusing are output. The focusing electrode is arranged at a position where it comes into contact with the connection terminal of the holder support member, and when the lens holder rotates together with the holder support member, the tracking electrode is electrically connected to the connection terminal of the coil that is excited in the tracking direction. The focusing electrode is electrically connected to the connection terminal of the coil that is excited in the focusing direction. Therefore, when the lens holder rotates, the direction of the coils also switches, but since the tracking electrodes and focusing electrodes that are electrically connected to these coils also switch,
Even if the lens holder rotates, the tracking electrode is electrically connected to the coil that generates the magnetic force in the tracking direction, and the focusing electrode is electrically connected to the coil that generates the magnetic force in the focusing direction.

According to a sixth aspect of the present invention, an objective lens facing an optical disk is mounted on a lens holder, and the lens holder is connected to a holder supporting member by an elastic member so as to be elastically displaced in a tracking direction and a focusing direction. In an optical head device that supports and forms a laser beam emitted from a laser optical system on the optical disc by the objective lens, a holder rotation unit that rotatably supports the holder support member in an axial direction parallel to the focusing direction. A moving mechanism is provided, a plurality of objective lenses are arranged on an arc centered on the axis of the holder rotating mechanism, and the holder supporting member is rotated to move one of the plurality of objective lenses to the laser optical system. A lens switching mechanism that is selectively arranged on the optical path is provided.
Therefore, when the holder rotation mechanism rotates the holder support member that supports the lens holder, the objective lens that images the laser light emitted from the laser optical system on the optical disk is switched. For this reason, it is not necessary to form one objective lens with a double focus using optical glass, and it is not necessary to mount a mechanism for switching the objective lens on the lens holder.

According to a seventh aspect of the present invention, an objective lens facing an optical disk is mounted on a lens holder, and the lens holder is connected to a holder supporting member by an elastic member so as to be elastically displaced in a tracking direction and a focusing direction. In an optical head device that supports and forms a laser beam emitted from a laser optical system on the optical disc by the objective lens, a plurality of objective lenses are continuously provided in the lens holder in a direction orthogonal to a focusing direction, and this direction And an optical system moving mechanism for movably supporting the laser optical system, and a lens switching mechanism for moving the laser optical system and selectively arranging the laser optical system on one optical axis of the plurality of objective lenses. Therefore, when the optical system moving mechanism moves the laser optical system, the objective lens for focusing the laser light emitted from this on the optical disk is relatively switched. For this reason, it is not necessary to form one objective lens with a double focus using optical glass, and it is not necessary to mount a mechanism for switching the objective lens on the lens holder.

[0015]

FIG. 1 shows a first embodiment of the present invention.
And it demonstrates below based on FIG. In the following,
Focusing direction is Fo, tracking direction is Tr,
Display as Further, for convenience sake, the direction orthogonal to the focusing direction and the tracking direction is called the tangential direction, and is shown as Ta in the figure.

The optical head device 1 exemplified here is provided as a part of an optical disk player (not shown). This optical disk player has a turntable that rotatably supports the optical disk 2. As shown in FIG. 1, the optical head device 1 is moved in the tracking direction to a position facing the optical disk 2 thus supported. Supports freely.

That is, the optical head device 1 has its main body base (not shown) supported so as to be movable in the tracking direction, and a pair of supports is provided on the shaft support portion 3 provided upright on the main body base. The shaft 4 is provided so as to project in the tangential direction. A holder support member 5 is slidably supported on these support shafts 4 in the tangential direction, and a drive coil 6 provided on the holder support member 5 and a magnet 7 standing on the main body base face each other. doing. As shown in FIG. 2, the holder supporting member 5 is provided with a bearing 8 for supporting the supporting shaft 4 via a damper member 9, which is made of a magnetic material such as steel.

Since the lens holder 11 is connected to the holder support member 5 by four wire springs 10 communicating in the tangential direction, the lens holder 11 is connected to the holder support member 5 by the wire spring 10. On the other hand, it is elastically held so as to be displaceable in the tracking direction and the focusing direction. A drive coil is mounted on one side of the lens holder 11 and the body base, and a magnet is mounted on the other side of the lens holder 11, and the magnetic attraction of the lens holder 11 causes the lens holder 11 to move in the tracking direction and the focusing direction. The displacement is driven in the direction.

On the lens holder 11, two objective lenses 12 and 13 are arranged in series in the tangential direction, and these objective lenses 12 and 13 are connected to the optical disc 2.
Opposite from the focusing direction. The optical disc 2 is, for example, a replaceable CD or DVD, and one of the objective lenses 12 and 13 has a light-condensing characteristic that corresponds to a CD and the other corresponds to a DVD. The objective lens 1
One laser optical system 1 fixed to the main body base is provided at a position facing the optical disc 2 via the optical discs 2 and 13.
4 is arranged, and the laser optical system 14 includes a laser diode 15, a collimator lens 16, and a reflection mirror 1.
7 are provided.

The holder support member 5 is slidably supported by the support shaft 4 in the tangential direction which is the arrangement direction of the objective lenses 12 and 13,
The holder slide mechanism 18 is formed here. Since the holder support member 5 slides by the magnetic attraction between the drive coil 6 and the magnet 7, one of the objective lenses 12 and 13 is selectively arranged on the optical path of the laser optical system 14. Lens switching mechanism 19
Are formed.

In such a structure, the optical disk player exemplified here is an optical disk 2 such as a CD and a DV.
Both D and can be played. For example, when reproducing a CD as the optical disc 2, the drive power set for this CD is applied to the drive coil 6 of the lens switching mechanism 19. Then, the holder support member 5 slides on the support shaft 4 in the tangential direction by the magnetic attraction between the drive coil 6 and the magnet 7, and the objective lens 1 for CD is used.
2 is arranged on the optical path of the laser optical system 14.

The laser light emitted from the laser diode 15 in such a state is shaped into a parallel light flux by the collimator lens 16 and then reflected by the objective lens 12 by the reflection mirror 17, so that the objective lens 12 emits the laser light. It converges and is incident on the track of the optical disc 2. At this time, since the objective lens 12 has a condensing characteristic corresponding to the CD, the laser light is well imaged on the track of the CD which is the optical disc 2. The laser light reflected in the focusing direction by the optical disc 2 is converged by the objective lens 12 and enters the laser optical system 14. Therefore, a light receiving element (not shown) of the laser optical system 14 reads the incident light and the optical disc. The recorded information of 2 is reproduced.

When the laser beam is reflected on the optical disc 2 to reproduce information as described above, when a tracking error is detected from the laser beam, the lens holder 11 is moved in the tracking direction in response to the tracking error. By controlling the position, the position of the spot imaged on the optical disc 2 by the objective lens 12 is adjusted on the track. Similarly, when a focusing error is detected, the position of the lens holder 11 is controlled in the focusing direction in response to the focusing error,
The image forming position of the laser beam by the objective lens 12 is adjusted on the track of the optical disc 2.

Furthermore, since the track relatively moves in the tracking direction due to the rotation of the optical disk 2, the seek of the track causes the entire optical head device 1 to move in the tracking direction.

When a DVD is reproduced as the optical disc 2, the drive power set for the DVD is applied to the drive coil 6 of the lens switching mechanism 19 so that the holder support member 5 moves on the support shaft 4 in the tangential direction. The objective lens 13 for DVD is arranged on the optical path of the laser optical system 14 by sliding to. In this state, the recorded information of the DVD is reproduced in the same manner as the case of the CD, so that the above-mentioned optical disc player has a different laminated structure between the CD and the DVD.
Both can be used.

The above-described optical head device 1 is a CD by switching the objective lenses 12 and 13 as described above.
It supports both DVD and DVD. At this time, the objective lens 1
Reference numerals 2 and 13 are arranged side by side in one lens holder 11 in the tangential direction, but the holder support member 5 that supports the lens holder 11 displaceably in the focusing direction and the tracking direction is slid in the tangential direction. Thus, the objective lenses 12 and 13 are switched.

That is, since the holder slide mechanism 18 and the lens switching mechanism 19 necessary for switching the objective lenses 12 and 13 are not mounted on the lens holder 11,
The lens holder 11 has a simple structure and is lightweight, and can perform focusing and tracking with good responsiveness. Moreover, the holder slide mechanism 18 is formed by a combination of the general support shaft 4 and the bearing 8, and does not have a mechanism for moving the objective lenses 12 and 13 inside the long hole, so that the operation is smooth. Good reliability.

Further, since the bearing 8 of the holder supporting member 5 is made of a magnetic material, it is magnetically attracted to the magnet 7 that slides the holder supporting member 5. Therefore, the holder support member 5 slides in a state of being biased by the magnet 7, and the backlash between the support shaft 4 and the bearing 8 does not affect the holder support member 5. Moreover,
Since the damper member 9 is provided around the bearing 8, the vibration of the player body is prevented from affecting the holder supporting member 5, and the objective lenses 12 and 13 are excellent in that vibration and rattling do not affect them. Supported by the state.

In the optical head device 1 described above, the objective lenses 12 and 13 are arranged with the direction orthogonal to the focusing direction as the tangential direction, but the present invention is not limited to the above structure. As shown in FIGS. 3 and 4, it is possible to form the optical head device 21 by arranging the objective lenses 12 and 13 in the tracking direction.

Next, a second embodiment of the present invention will be described with reference to FIG.
And it demonstrates below based on FIG. Regarding the optical head device 31 exemplified here, the same parts as those of the above-described optical head device 1 are denoted by the same names and reference numerals, and detailed description thereof will be omitted.

First, the optical head device 31 exemplified here.
Is a single support shaft 34 attached to the shaft support portion 33 of the main body base 32.
Are provided so as to project in the tangential direction, and the holder support member 35 is rotatably supported by the support shaft 34. This holder support member 35 is formed as a worm wheel, and is combined with a worm 37 directly connected to a stepping motor 36.

A lens holder 38 is connected to the holder supporting member 35 by four wire springs 10, and the lens holder 38 is formed in a rectangular parallelepiped shape. Since the two objective lenses 12 and 13 are mounted on the two surfaces parallel to the tangential direction of the lens holder 38, the objective lenses 12 and 13 are located at the axis of rotation of the lens holder 38. Are arranged on an arc centered at. That is, the lens holder 38 is rotatably supported by the support shaft 34 parallel to the tangential direction.
One of the optical axes 2 and 13 is located in the focusing direction and the other is located in the tracking direction.

Drive coils 39 and 40 are wound around the lens holder 38 in two directions, and the excitation directions of these drive coils 39 and 40 correspond to the optical axis directions of the objective lenses 12 and 13. . On the end surface of the holder supporting member 35, two sets of connecting terminals 41 and 42, each of which is a set, are provided in an arc shape, and these two sets of connecting terminals 41 and 4 are provided.
Reference numeral 2 is individually connected to the two drive coils 39 and 40 by using the four wire springs 10 as wiring.

On the main body base 32, a pair of two tracking electrodes 43 and a focusing electrode 44 are provided upright, and these electrodes 43 and 44 are resiliently connected to the connection terminals 41 and 42. Abutting. That is, the tracking electrode 43 and the focusing electrode 44 are connected to the drive coils 39 and 40, but the connection terminals 41 and 42 that contact the electrodes 43 and 44 when the holder support member 35 rotates. Since the directions of the drive coils 39 and 40 are switched to each other as well as to each other, the tracking electrode 43 is connected to the drive coil 3.
The focusing electrode 44 is connected to one of the excitation coil 9 and 40 which is excited in the tracking direction.
9 and 40 are connected to the other exciting in the focusing direction.

A tip portion 45 of the support shaft 34 is formed in a flat plate shape, and a magnet 46 having different polarities at the center and both sides is mounted on the tip portion 45. A similar magnet 48 is also mounted on the magnet supporting portion 47 provided upright on the main body base 32.
Faces the drive coils 39 and 40 of the lens holder 38.

Since the holder supporting member 35 is rotatably supported by the supporting shaft 34 parallel to the tangential direction, a holder rotating mechanism 49 is formed here. When the stepping motor 36 rotationally drives the holder support member 35 by the worm 37, one of the objective lenses 12 and 13 is selectively arranged on the optical path of the laser optical system 14, so that the lens switching is performed here. The mechanism 50 is formed.

In such a configuration, the optical head device 31 exemplified here is also the optical disc 2 such as a CD and a DV.
It corresponds to both D and. When reproducing a CD as the optical disc 2, the lens switching mechanism 50 drives the holder support member 35 to rotate on the support shaft 34, and the objective lens 12 for CD is arranged on the optical path of the laser optical system 14.
When reproducing a DVD as the optical disk 2, the holder supporting member 35 is moved by the lens switching mechanism 50.
4, the objective lens 13 for DVD is arranged on the optical path of the laser optical system 14.

With the lens holder 38 thus rotated and one of the objective lenses 12 and 13 faces the optical disc 2, the optical head device 31 reproduces the recorded information on the optical disc 2 by the laser optical system 14. Since the holder rotation mechanism 49 and the lens switching mechanism 50 necessary for switching the objective lenses 12 and 13 are not mounted on the lens holder 38, the lens holder 38 has a simple structure and is lightweight, and focusing and focusing are possible. Tracking and can be performed with good responsiveness. Moreover, the holder rotation mechanism 4
Reference numeral 9 denotes an objective lens 1 which is formed by a general shaft support structure.
Since 2 and 13 do not have a mechanism for moving inside the long hole, the operation is smooth and the reliability is good.

When the optical head device 31 executes tracking control or focusing control as described above, the lens holder 38 tracks the main body base 32 due to the magnetic forces of the drive coils 39 and 40 and the magnets 46 and 48. The position is adjusted in the direction and the focusing direction. This lens holder 38 is used for the objective lenses 12, 13
When it is rotated to switch the drive coil 39,
Although the direction of 40 also changes, these drive coils 39,
Since the electrodes 43 and 44 conducting to 40 are also switched, the driving power for tracking control is supplied from the tracking electrode 43 to the one exciting the driving coils 39 and 40 in the tracking direction, and the driving power for focusing control is driven from the focusing electrode 44. It is supplied to the other of the coils 39 and 40 that are excited in the focusing direction.

That is, even if the directions of the driving coils 39 and 40 are changed by the rotation of the lens holder 38, the driving power for tracking control is supplied to the tracking electrode 43 and the driving power for focusing control is supplied to the focusing electrode 44. It suffices, and it is not necessary to control the switching of the electrodes 43 and 44. Moreover, since such driving power is transmitted from the holder supporting member 35 to the lens holder 38 by the wire spring 10, no dedicated wiring is required and the structure is simplified. Further, since the magnet 46 facing the drive coils 39, 40 of the lens holder 38 is attached to the tip end portion 45 of the support shaft 34 that supports the holder support member 35, the magnet 46 has a simple structure. Is supported without affecting the rotation of the.

Furthermore, FIG. 7 shows a third embodiment of the present invention.
This will be described below based on Regarding the optical head device 51 exemplified here, the same parts as those of the above-described optical head device 21 are denoted by the same names and reference numerals, and detailed description thereof will be omitted.

First, the optical head device 51 exemplified here.
A hinge mechanism 53 is provided on a hinge supporting portion 52 of a main body base (not shown) so as to project in the focusing direction, and the holder supporting member 5 is rotatably supported by the hinge mechanism 53. A magnet 54 is attached to the side of the end surface of the holder support member 5, and a drive coil 55 facing the magnet 54 is fixed to the hinge support portion 52. Further, a stopper member 56 is provided at one end of the hinge support portion 52 opposite to the drive coil 55, and the stopper member 56 faces the end surface of the holder support member 5 so as to be contactable and separable. doing.

The lens holder 11 has two objective lenses 1
Since the reference numerals 2 and 13 are arranged side by side in the tracking direction, these objective lenses 12 and 13 are arranged on an arc centered on the axis of rotation of the lens holder 11 by the hinge mechanism 53. Since the holder supporting member 5 is rotatably supported by the hinge mechanism 53 whose focusing direction and axis direction are parallel to each other, a holder rotating mechanism 57 is formed here. Then, the drive coil 55
When the holder supporting member 5 is rotationally driven by the magnetic force of the magnet 54, one of the objective lenses 12 and 13 is selectively arranged on the optical path of the laser optical system 14,
A lens switching mechanism 58 is formed here.

In such a configuration, when the optical head device 51 reproduces a CD as the optical disc 2, the lens switching mechanism 58 rotates the holder supporting member 5 to rotate the CD.
The objective lens 12 for laser light is arranged on the optical path of the laser optical system 14. Further, when reproducing a DVD as the optical disc 2, the lens switching mechanism 58 rotates the holder support member 5 and the objective lens 13 for the DVD is arranged on the optical path of the laser optical system 14.

Since the holder rotating mechanism 57 and the lens switching mechanism 58 necessary for switching the objective lenses 12 and 13 are not mounted on the lens holder 11, the lens holder 11 has a simple structure and is lightweight. Yes, focusing and tracking can be performed with good responsiveness. Moreover, since the holder rotating mechanism 57 is formed by the general hinge mechanism 53 and does not have a mechanism for moving the objective lenses 12 and 13 inside the long hole, the operation is smooth and the reliability is good. is there.

Although the holder supporting member 5 is rotatably and pivotally supported by the hinge mechanism 53 provided upright on the main body base, the present invention is not limited to the above-described structure. It is also possible to form the optical head device 61 by pivotally supporting the main body base 59 integrally formed with the holder supporting member 5 with respect to the main body housing 60, as shown in FIG.

Furthermore, FIG. 9 shows a fourth embodiment of the present invention.
And it demonstrates below based on FIG. Regarding the optical head device 71 illustrated here, the same parts as those of the above-described optical head device 21 are denoted by the same names and reference numerals, and detailed description thereof will be omitted.

First, the optical head device 71 exemplified here.
The holder support member 5 is fixed to the main body base 72, and the reflection mirror 17 of the laser optical system 74 is slidably supported in the tracking direction by the solenoid 73 fixed to the main body base 72. The reflection mirror 17 is movably supported by the solenoid 73, and the reflection mirror 17 includes two objective lenses 12 and 13.
The optical system moving mechanism 75 and the lens switching mechanism 76 are formed here because they are selectively arranged on one optical axis.

In such a structure, when the optical head device 71 reproduces a CD as the optical disc 2, the lens switching mechanism 76 causes the reflection mirror 17 of the laser optical system 74.
Is moved, and the reflection mirror 17 is arranged on the optical axis of the objective lens 12 for CD. Also, as the optical disc 2, D
When reproducing VD, the lens switching mechanism 76 moves the reflection mirror 17 of the laser optical system 74, and arranges this reflection mirror 17 on the optical axis of the objective lens 13 for DVD.

Since the optical system moving mechanism 75 and the lens switching mechanism 76 required for switching between the objective lenses 12 and 13 are not mounted on the lens holder 11, the lens holder 11 has a simple structure and is lightweight. Yes, focusing and tracking can be performed with good responsiveness. Moreover, since the optical system moving mechanism 75 is formed of the general solenoid 73 and does not have a mechanism for moving the objective lenses 12 and 13 inside the long hole, the operation thereof is smooth and the reliability is good. .

As shown in FIG. 11, the solenoid 7
It is also possible to improve the positional accuracy of the reflection mirror 17 by elastically supporting the reflection mirror 17 to be moved by 3 with a pair of leaf springs 77.

[0052]

According to the first aspect of the present invention, a plurality of objective lenses are continuously provided on the lens holder in a direction orthogonal to the focusing direction, and a holder slide mechanism for slidably supporting the holder support member in this direction is provided. By providing the lens switching mechanism that slides the holder supporting member to selectively dispose one of the plurality of objective lenses on the optical path of the laser optical system, it is necessary to mount a mechanism for switching the plurality of objective lenses on the lens holder. Since it does not exist, the lens holder has a simple structure and is lightweight, and can perform tracking and focusing with good responsiveness.

According to the second aspect of the present invention, the holder slide mechanism is provided with the damper member for absorbing the vibration, and the holder support member is made of the magnetic material, so that the damper member absorbs the vibration generated in the holder slide mechanism. Since the holder support member and the holder slide mechanism can be brought into close contact with each other by the magnetic attractive force, the holder support member can be movably supported in a state in which vibration does not affect, and deterioration of optical characteristics due to vibration can be prevented. be able to.

According to a third aspect of the present invention, a holder rotating mechanism for rotatably supporting the holder supporting member in an axial direction parallel to the tangential direction is provided, and an arc centered on the axial center of the holder rotating mechanism. By arranging a plurality of objective lenses on the upper side and rotating the holder supporting member to provide a lens switching mechanism for selectively disposing one of the plurality of objective lenses on the optical path of the laser optical system, a plurality of objective lenses are provided. Since it is not necessary to mount a mechanism for switching the lens holder on the lens holder, the lens holder has a simple structure and is lightweight, and tracking and focusing can be performed with good responsiveness.

According to the fourth aspect of the present invention, the holder rotating mechanism has a support shaft that passes through the holder support member and faces the lens holder, and the magnet is provided on one of the end faces of the support shaft and the lens holder that face each other. By arranging and the coil on the other side, it is possible to arrange the magnet and the coil at a position that does not hinder the rotation of the lens holder with a simple structure.

According to the fifth aspect of the present invention, two objective lenses are mounted on the lens holder in the directions in which the optical axes are orthogonal to each other, and two types of coils that are excited in these directions are mounted on the lens holder, and two types of coils are mounted. The holder supporting member is provided with two sets of connecting terminals individually connected to the coil, and the tracking supporting electrode for outputting the driving power for tracking the objective lens and the focusing electrode for outputting the driving power for focusing are connected to the supporting terminal for the holder supporting member. When the lens holder rotates together with the holder supporting member at the contact position, the tracking electrode is electrically connected to the connecting terminal of the coil which is excited in the tracking direction, and the focusing electrode is electrically connected to the connecting terminal of the coil which is excited in the focusing direction. As a result, when the lens holder rotates, the coil direction also changes. Since the tracking electrode and the focusing electrode that are electrically connected to each other are switched, the driving power for tracking control can be supplied from the tracking electrode to the coil that generates the magnetic force in the tracking direction regardless of the rotation of the lens holder. Driving power can be supplied from the focusing electrode to a coil that generates a magnetic force in the focusing direction.

According to a sixth aspect of the present invention, there is provided a holder rotating mechanism for rotatably supporting the holder supporting member in an axial direction parallel to the focusing direction, and an arc centered on the axial center of the holder rotating mechanism. By arranging a plurality of objective lenses on the upper side and rotating the holder supporting member to provide a lens switching mechanism for selectively disposing one of the plurality of objective lenses on the optical path of the laser optical system, a plurality of objective lenses are provided. Since it is not necessary to mount a mechanism for switching the lens holder on the lens holder, the lens holder has a simple structure and is lightweight, and tracking and focusing can be performed with good responsiveness.

According to a seventh aspect of the present invention, a plurality of objective lenses are continuously provided on the lens holder in a direction orthogonal to the focusing direction, and an optical system moving mechanism for movably supporting the laser optical system in this direction is provided. By providing a lens switching mechanism that moves the optical system and selectively arranges it on one optical axis of a plurality of objective lenses, it is not necessary to mount a mechanism for switching a plurality of objective lenses on the lens holder.
This lens holder has a simple structure and is lightweight, and can perform tracking and focusing with good responsiveness.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an optical head device according to a first embodiment of the invention.

FIG. 2 is a vertical sectional front view showing an internal structure of a holder support member.

FIG. 3 is a perspective view showing an optical head device of a modified example.

FIG. 4 is a vertical cross-sectional side view showing an internal structure of a holder support member.

FIG. 5 is a perspective view showing an optical head device of a second embodiment of the invention.

FIG. 6 is a vertical sectional side view showing the internal structure of the optical head device.

FIG. 7 is a perspective view showing an optical head device of a third embodiment of the invention.

FIG. 8 is an exploded perspective view showing an optical head device of a modified example.

FIG. 9 is a perspective view showing an optical head device according to a fourth embodiment of the present invention.

FIG. 10 is a vertical cross-sectional front view showing the internal structure of the optical head device.

FIG. 11 is a perspective view showing a main part of a modified example.

[Explanation of symbols]

 1, 21, 31, 51, 61, 71 Optical head device 2 Optical disk 5,35 Holder support member 9 Damper member 10 Elastic member 11,38 Lens holder 12,13 Objective lens 14,74 Laser optical system 18 Holder slide mechanism 19, 50, 58, 76 Lens switching mechanism 34 Support shaft 39, 40 Coil 41, 42 Connection terminal 43 Tracking electrode 44 Focusing electrode 46 Magnet 49, 57 Holder rotating mechanism 75 Optical system moving mechanism

Claims (7)

[Claims] 1. A laser optical system in which an objective lens facing an optical disc is mounted on a lens holder, and the lens holder is elastically supported by a resilient member to be elastically supported so as to be displaceable in a tracking direction and a focusing direction. In an optical head device for forming an image of laser light emitted from the optical disc on the optical disc by the objective lens, a plurality of objective lenses are continuously provided in the lens holder in a direction orthogonal to the focusing direction, and the holder support member is provided in this direction. A holder slide mechanism that slidably supports is provided, and a lens switching mechanism that slides the holder support member to selectively arrange one of the plurality of objective lenses on an optical path of the laser optical system is provided. Optical head device. 2. The optical head device according to claim 1, wherein a damper member for absorbing vibration is provided in the holder slide mechanism, and the holder supporting member is made of a magnetic material. 3. A laser optical system in which an objective lens facing an optical disk is mounted on a lens holder, and the lens holder is connected to a holder supporting member by an elastic member to elastically support the lens holder so as to be displaceable in a tracking direction and a focusing direction. In an optical head device for forming an image of laser light emitted from the optical disc on the optical disc by the objective lens, a holder rotating mechanism for rotatably supporting the holder supporting member in an axial direction parallel to the tangential direction is provided, A plurality of objective lenses are arranged on an arc centered on the axis of the holder rotating mechanism, and the holder supporting member is rotated to selectively place one of the plurality of objective lenses on the optical path of the laser optical system. An optical head device characterized in that a lens switching mechanism arranged at the position is provided. 4. The holder rotating mechanism has a support shaft that passes through the holder support member and faces the lens holder, and a magnet is arranged on one of the end faces of the support shaft and the lens holder, which face each other, and the other end. The optical head device according to claim 3, wherein a coil is disposed in the optical head device. 5. The two objective lenses are mounted on the lens holder in the directions in which the optical axes are orthogonal to each other, and the two types of coils that are excited in these directions are mounted on the lens holder, and the two types of the coils are individually attached. Two sets of connected connecting terminals are provided on the holder supporting member, and a tracking electrode for outputting the driving power for tracking the objective lens and a focusing electrode for outputting the driving power for focusing are brought into contact with the connecting terminal of the holder supporting member. When the lens holder is placed at a position and rotates together with the holder supporting member, the tracking electrode is electrically connected to the connection terminal of the coil that is excited in the tracking direction, and the focusing terminal is connected to the connection terminal of the coil that is excited in the focusing direction. The optical head device according to claim 3, wherein the electrodes are electrically connected. 6. A laser optical system in which an objective lens facing an optical disk is mounted on a lens holder, and the lens holder is connected to a holder supporting member by an elastic member to elastically support the lens holder so as to be displaceable in a tracking direction and a focusing direction. An optical head device for forming an image of laser light emitted from the optical disc on the optical disc by the objective lens is provided with a holder rotation mechanism for rotatably supporting the holder support member in an axial direction parallel to the focusing direction. A plurality of objective lenses are arranged on an arc centered on the axis of the holder rotating mechanism, and the holder supporting member is rotated to selectively move one of the plurality of objective lenses onto the optical path of the laser optical system. An optical head device comprising a lens switching mechanism to be arranged. 7. A laser optical system in which an objective lens facing an optical disk is attached to a lens holder, and this lens holder is elastically supported to be elastically supported by a holder supporting member so as to be displaceable in a tracking direction and a focusing direction. In an optical head device for forming an image of laser light emitted from the optical disc on the optical disc by the objective lens, a plurality of objective lenses are connected to the lens holder in a direction orthogonal to the focusing direction, and the laser optical system is arranged in this direction. An optical head comprising an optical system moving mechanism for movably supporting the lens, and a lens switching mechanism for moving the laser optical system to selectively dispose on the optical axis of one of the plurality of objective lenses. apparatus.