JP3039715B2 - Optical disk player - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk player for preventing vibration.

[0002]

2. Description of the Related Art An optical system and a servo system for reproducing an optical disk such as a CD (compact disk) player and an LD (laser disk) player accurately track and focus on externally applied vibrations and the like. Have a limited ability to do

For this reason, a structure is employed in which the entire mechanism or the reproducing mechanism (optical mechanism) is elastically supported to attenuate external vibration. FIG. 1 shows an LD player as an example of a player having a structure for damping such external vibration. A mechanical chassis 4 is provided on a housing 1 via a floating spring 3 provided on a support member 2. Are elastically supported at the four corners. Thus, the mechanical chassis 4 is in a floating state with respect to the housing 1.

A spindle motor 7 having a turntable 6 for rotating the optical disk 5 is mounted on the front side of the mechanical chassis 4. A speed detecting sensor 8 having a speed detecting coil 12 integrated with the spindle motor 7 is provided on the lower surface side of the mechanical chassis 4. The speed detection sensor 8 includes a U-shaped side yoke 9 extending along the radial direction of the optical disk 5, a speed detection magnet 10 fixed inside the center side yoke, a center yoke 11 attached to both ends of the side yoke 9, and a center. The speed detecting coil 12 is loosely fitted to the yoke 11. In addition,
The side yoke 9, the speed detecting magnet 10, and the side yoke 9 are fixed to the lower surface of the mechanical chassis 4.

[0005] On both sides in the middle of the mechanical chassis 4, there are provided support pieces 13 obtained by bending a part of the mechanical chassis 4 in the vertical direction. Inside each support piece 13, linear motor portions 14 and 15 extending in the same direction as the speed detection sensor 8 are provided. Side yokes 14 a, 15 a having a U-shaped cross section of the linear motor portions 14, 15 are fixed to the inside of the support piece 13. Driving magnets 14b and 15b are fixed inside the side yokes 14a and 15a such that the magnetic poles face each other as described later. Center yokes 14 are provided at both ends of each side yoke 14a, 15a.
c and 15c are fixed. Each center yoke 14
Drive coils 14e and 15e described later are loosely fitted to c and 15c.

A rail support member 16 is provided on the mechanical chassis 4.
a, 16b, 16c, 16d are fastened by screws 17. Each rail support member 16a, 16b and 16
Guide rails 18 and 19 are extended between c and 16d in parallel with the linear motor sections 14 and 15. The detachment of the guide rails 18 and 19 from the respective rail support members 16a, 16b, 16c and 16d is prevented by the head of the screw 17.

The pickup mounting plate 20 has a total of four rollers 2 along the axial direction of the guide rails 18 and 19.
1 is rotatably mounted. Each roller 21 is formed with a depression 22 along the outer peripheral surface.
Is pressed into engagement with the guide rails 18 and 19, so that the pickup mounting plate 20 is positioned away from the mechanical chassis 4.

In the middle of the pickup mounting plate 20, an optical pickup 24 having a pickup head 23 is mounted. Pickup mounting plate 2
The coil holding members 25 and 26 that hold the annular drive coils 14e and 15e are provided on both sides of the zero.
The above-described movement of the optical pickup 24 in the radial direction of the optical disk 5 is performed based on the principle shown in FIG.

That is, the magnetic flux from the drive magnets 14b, 15b in the linear motor units 14, 15 is supplied to the center yokes 14c, 15c and the side yokes 14a, 15a.
To form a loop. When a drive current is supplied to each of the drive coils 14e and 15e in the direction shown in the figure, F = BIL (B: magnetic flux density, I: current, L:
(Effective length of the coil). Therefore, the optical pickup 24 is pushed in the direction of the force F.

At this time, the speed detecting coil 12 of the speed detecting sensor 8 generates e = BLv (e: electromotive force generated in the speed detecting coil, L: effective length of the coil, v: moving speed of the optical pickup). Electric power is generated. Speed detection coil 1
The moving speed of the optical pickup 24 can be detected by monitoring the terminal voltage of No. 2.

On the other hand, with respect to external vibration, the mechanical chassis 4 is connected to the housing 1 via the floating spring 3 of the support member 2.
In this case, the floating spring 3 prevents the mechanical chassis 4 from vibrating. Accordingly, the optical disk 5 and the optical pickup 24 do not vibrate, so that appropriate tracking and focusing are performed.

[0012]

However, the above-described optical disk player has a structure in which the entire mechanism or the reproducing mechanism (optical system mechanism) is elastically supported to attenuate external vibrations, and the optical pickup is moved by a linear motor system. This causes the following problems.

That is, the movement of the optical pickup 24 in the radial direction of the optical disk 5 is as shown in FIG.
Each drive magnet 14b, 15b and each drive coil 14
This is performed by being pushed out by the force obtained by the reaction force of the magnetic flux with e and 15e.

At this time, since the pickup mounting plate 20 on which the optical pickup 24 is mounted has a considerable weight, a reaction force in a direction opposite to the pushing force of the optical pickup 24 is applied to each of the drive magnets 14b, 15b. Conveyed to. Therefore, the mechanical chassis 4 has a structure that is hardly affected by external vibrations due to the action of the floating springs 3. On the other hand, the action of the floating spring 3 causes the mechanical chassis 4 itself to easily vibrate.

As described above, the pickup mounting plate 2
If the mechanical chassis 4 itself vibrates due to the vibration caused by the movement on the 0 side, the optical pickup 24 and the optical disk 5 vibrate, so that an appropriate tracking error signal cannot be obtained, Various problems such as occurrence of jitter in the reproduced RF signal occur.

The present invention has been made in view of such circumstances, and an appropriate tracking error signal can be obtained by fixing a member to be a cause of internal vibration to a housing side separately from an elastic support. It is an object of the present invention to provide an optical disc player that can obtain the reproduced RF signal and prevent the jitter.

[0017]

According to the present invention, there is provided a mechanical chassis mounted on a housing in a floating state via an elastic support, and a radius of an optical disk along a guide rail mounted on the mechanical chassis. An optical pickup mounting plate guided in the direction, and a pickup drive motor fixed to the housing via a support of a sub-plate provided separately from the mechanical chassis.

In the optical disc player having such a configuration, when external vibration is applied to the housing, the mechanical chassis is mounted in a floating state with respect to the housing, so that the vibration to the mechanical chassis is prevented by the action of the spring. In addition, since the magnet, center yoke, and side yoke of the pickup drive motor are attached to the housing via the support of the sub-plate provided separately from the mechanical chassis, the pickup mounting the optical pickup is mounted. The reaction force against the pressing force on the plate side can be received by the relatively heavy casing.

Therefore, the optical pickup maintains a structure that is hardly affected by external vibrations due to the elastic support function, and is relatively heavy against the reaction force at the time of movement of the optical pickup which causes internal vibrations. It can be received by a case with a frame.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, portions common to those in FIGS. 1 to 4 are denoted by the same reference numerals, and redundant description will be omitted.

FIGS. 5 to 7 show an embodiment of an optical disk player according to the present invention.
The mechanical chassis 4 is floatingly supported via a floating spring 3 provided in the mechanical chassis 4. Housing 1
A sub plate 32 is mounted on the upper side via a support 31. On both sides in the middle of the sub-plate 32, support pieces 33 obtained by bending a part of the sub-plate 32 in the vertical direction are provided.
Is provided. Inside each support piece 33, linear motor portions 14 and 15 extending in the same direction as the speed detection sensor 8 are provided. Side yokes 14 a, 15 a having a U-shaped cross section of the linear motor portions 14, 15 are fixed inside the support piece 33.

The driving magnets 14 are provided inside the side yokes 14a and 15a such that the magnetic poles are directed in opposite directions.
b and 15b are fixed. That is, the N pole side of one drive magnet 14 b is directed to the other linear motor unit 15. The S pole side of the other drive magnet 15b faces the one linear motor unit 14. Center yokes 14 are provided at both ends of each side yoke 14a, 15a.
c and 15c are fixed. Each center yoke 14
Drive coils 14e and 15e described later are loosely fitted to c and 15c.

On the front side of the mechanical chassis 4, a spindle motor 7 having a turntable 6 for rotating the optical disk 5 is mounted. A speed detecting sensor 8 having a speed detecting coil 12 integrated with the spindle motor 7 is provided on the lower surface side of the mechanical chassis 4. The speed detection sensor 8 includes a side yoke 9, a speed detection magnet 10, a center yoke 11, and a speed detection coil 12. The side yoke 9, the speed detecting magnet 10, and the side yoke 9 are fixed to the lower surface of the sub-plate 32.

A rail support member 16 is provided on the mechanical chassis 4.
a, 16b, 16c, 16d are fastened by screws 17. Each rail support member 16a, 16b and 16
Guide rails 18 and 19 are extended between c and 16d in parallel with the linear motor sections 14 and 15.

On the pickup mounting plate 20, the depressions 22 are pressed and engaged with the guide rails 18, 19,
1 is rotatably mounted. An optical pickup 24 having a pickup head 23 is mounted in the middle of the pickup mounting plate 20. On both sides of the pickup mounting plate 20, coil holding members 25, 26 for holding the annular drive coils 14e, 15e are provided.
Is provided. The drive coils 14e and 15e are loosely fitted to the center yokes 14c and 15c.

In the optical disk player having such a configuration, when external vibration is applied to the housing 1, the mechanical chassis 4
Is floating with respect to the housing 1 via the floating spring 3 of the support member 2, so that the vibration of the mechanical chassis 4 is prevented by the action of the floating spring 3. Accordingly, the optical disk 5 and the optical pickup 24 do not vibrate, so that appropriate tracking and focusing are performed.

On the other hand, the movement of the optical pickup 24 in the radial direction of the optical disk 5 is controlled by the drive magnets 14b,
This is performed by being pushed out by the force obtained by the reaction force of the magnetic flux between the drive coils 15b and the drive coils 14e and 15e. At this time, a reaction force in a direction opposite to the pushing force of the optical pickup 24 is transmitted to each of the drive magnets 14b and 15b.

Here, the drive magnets 14b, 15b, the center yoke 14c,
15c and the side yokes 14a, 15a are supported by the support pieces 3 of the sub-plate 32 provided separately from the mechanical chassis 4.
3, the reaction force against the pushing force on the side of the pickup mounting plate 20 on which the optical pickup 24 is placed is relatively heavy.
Can be received by

Therefore, the mechanical chassis 4 maintains a structure that is hardly affected by external vibration due to the action of the floating spring 3.
Can be received by the relatively heavy casing 1 via the sub-plate 32 against the vibration caused by the reaction force at the time of the movement caused by the pickup mounting plate 20 on which is mounted.

FIG. 9 shows an example of a drive circuit for supplying a drive current to each of the linear motor units 14 and 15, and the non-inverting input terminal of the operational amplifier 30 is grounded.
A speed detecting coil 12 is connected to the inverting input terminal via a resistor R1. A positive or negative control signal is input to the inverting input terminal via a resistor R2. Further, a gain adjustment circuit including resistors R3, R4, C1, and C2 is interposed between the output terminal of the operational amplifier 30 and the inverting input terminal.

Then, the drive current is supplied to one drive coil 14e in the direction shown in FIG. 8 by the drive current supplied from the drive circuit. Thus, F = BIL occurs in the direction of the arrow according to Fleming's law. The other drive coil 15e has one drive coil 1 as shown in FIG.
The driving current is supplied in the opposite direction to the 4e side. At this time, the S pole side of the drive magnet 15b is connected to the drive coil 15e.
Side, so that F = BI which occurs in the same manner as above
The direction of L is the same as the direction of F generated on one linear motor unit 14 side.

Therefore, the optical pickup is pushed out in the direction of arrow F. When the optical pickup moves in the direction of arrow F, an electromotive force e is generated in the speed detection coil 12 in the direction of arrow. At this time, each drive coil 1
The directions of the magnetic fields from 4e and 15e are reversed in the speed detection coil 12. Thereby, each drive coil 14e, 1
The magnetic field forces from 5e are respectively equal and opposite, and are mutually weakened and counteracted. Each linear motor unit 1
The driving magnets 14b, 15b are arranged so that the magnetic poles of the driving magnets 14b, 15b are different from each other, and the driving currents are supplied to the respective driving coils 14e, 15e in opposite directions. The direction of the force to push out the type pickup can be the same.

At this time, the directions of the magnetic fields from the drive coils 14e and 15e exerted on the speed detection sensor 8 provided at the intermediate portion between the linear motor sections 14 and 15 are made opposite to each other by the speed detection coil 12. You. Therefore, the magnetic field forces from the drive coils 14e and 15e are equal and opposite to each other, and are mutually weakened and canceled.

Therefore, the effect of the external magnetic field on the electromotive force generated in the speed detecting coil 12 is prevented, so that no error occurs in the electromotive force. In addition, the feedback amount of the detection result from the speed detection sensor 8 is increased, and furthermore, no error occurs in the electromotive force, so that the speed control band is expanded, so that stable linear motor driving is performed.

As described above, in this embodiment, the side yokes 14a, 15a, the center yokes 14c, 15c, and the driving magnets 14b, 1 of the linear motor units 14, 15 are used.
5b was attached to the housing 1 via the support piece 33 of the sub-plate 32 provided separately from the mechanical chassis 4. On the other hand, the mechanical chassis 4 on which the pickup mounting plate 20 and the like on which the optical pickup 24 is mounted is placed in a floating state with respect to the housing 1 via the floating spring 3 of the support member 2.

Therefore, the mechanical chassis 4 maintains a structure that is hardly affected by external vibrations due to the action of the floating springs 3, and is resistant to vibrations caused by a reaction force caused when the pickup mounting plate 20 moves. The relatively heavy casing 1 via the sub-plate 32
Can be received by Accordingly, the optical disk 5 and the optical pickup 24 do not vibrate, so that appropriate tracking and focusing are performed.

[0037]

As described above, according to the optical disk player of the present invention, the turntable, the optical pickup and the drive coil are elastically supported on the housing via the support member, and the yoke and the drive magnet are mounted on the housing. Fixed to the body. As a result, the optical pickup maintains a structure that is hardly affected by external vibration due to the elastic support function, and is relatively heavy against the reaction force at the time of movement of the optical pickup that causes internal vibration. It can be received by the housing. Therefore, since both the internal vibration and the external vibration are absorbed, the vibration of the optical pickup and the optical disk is prevented, an appropriate tracking error signal can be obtained, and the jitter of the reproduced RF signal can be prevented.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a conventional optical disc player.

FIG. 2 is a front view showing the optical disc player of FIG. 1;

FIG. 3 is a right side view showing the optical disc player of FIG. 1;

FIG. 4 is a diagram showing the principle of the linear motor unit of FIG.

FIG. 5 is a plan view showing an embodiment of the optical disc player of the present invention.

FIG. 6 is a front view showing the optical disk player of FIG. 5;

FIG. 7 is a right side view showing the optical disc player of FIG. 5;

8 is a diagram showing the principle of a linear motor unit of the optical disk player of FIG.

9 is a diagram showing a drive circuit for supplying a drive current to each linear motor unit of the optical disc player of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Support member 3 Floating spring 4 Mechanical chassis 5 Optical disk 8 Speed detection sensor 9, 14a, 15a Side yoke 10 Speed detection magnet 11, 14c, 15c Center yoke 12 Speed detection coil 14, 15 Linear motor part 14e, 15e Drive Coil 20 Pickup mounting plate 31 Support 32 Subplate 33 Supporting piece

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G11B 7/085 G11B 21/02 612 G11B 25/04 101

Claims (1)

(57) [Claims] 1. Floating on a housing via an elastic support
A mechanical chassis attached to the state, Along the guide rail attached to the mechanical chassis
Optical pickup guided in the radial direction of the optical disk
Mounting plate, Of the sub plate provided separately from the mechanical chassis
Pickup drive module fixed to the housing via a support
Optical disc player, comprising:
Ya.