JP2001344789A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the size of an optical disk device for performing inclination correction (tilt correction) smaller, the accuracy of the inclination correction higher, the speed of operation higher, and the stability to vibration or impact higher. SOLUTION: A spring member 28 in one supporting section 13 presses the end of a turning shaft 10c of a movable chassis 10 toward a y direction. The end of the turning shaft 10b subjected to the pressing is abutted and positioned to a stop wall part formed in a V-groove 25a of a bearing 25. Spring members 27 and 28 are screwed and fixed to a stationary chassis 2 by a regulating member. The regulating member regulate more than specified deformation and displacement of the spring members 27 and 28 when disturbance such as impact is added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus having a structure for optically recording / reproducing information by irradiating an optical disk with a light beam emitted from an optical pickup. Is related to a tilt correction (tilt correction) mechanism that corrects the image to be kept vertical.

[0002]

2. Description of the Related Art With the recent increase in recording density on optical disks, the bit size on optical disks has been reduced. Therefore, it is necessary to reduce the diameter of the light spot focused on the optical disk. However, if the NA of the objective lens that focuses the light beam as the light spot on the optical disk is increased, the wavefront is increased due to the tilt of the optical axis of the light beam and the disk surface. Aberration occurs. Therefore, it is necessary to keep the optical axis of the light beam perpendicular to the disk surface.

[0003] As a method for keeping the light beam and the disk surface perpendicular, there are a method of adjusting at the time of assembling the drive,
There is a method of correcting the inclination of the light beam and the disk surface depending on the position of the optical pickup during the drive operation.

As an example of the latter method, there is a method using a two-layer chassis and a tilt correcting mechanism. The chassis is
It has a two-piece structure: a fixed chassis on which a spindle motor for rotating a disk is mounted, and a movable chassis on which a seek mechanism for moving the optical pickup is mounted.
Then, the movable chassis is rotated about the rotation axis with respect to the fixed chassis by the tilt correction mechanism, and the optical pickup is tilted so that the optical axis of the light beam is maintained perpendicular to the disk surface. ing.

[0005] As a tilt correction mechanism, DC is used as a power source.
2. Description of the Related Art A motor is widely used, and the height of a rotation driving point with respect to one end of a movable chassis is adjusted using a mechanism such as an adjusting screw or a driving cam. In order to keep the optical axis of the light beam perpendicular to the disk surface with high precision, the rotation axis and the rotation drive point should be set so that there is no play between the rotation axis and the rotation drive point provided on the movable chassis. Is held.

For example, in an optical disk device described in Japanese Patent Application Laid-Open No. 11-161991, an optical pickup supported on a guide shaft, a movable base supported on the guide shaft and provided rotatably with respect to a reference base are disclosed. Correction means for adjusting the tilt angle by rotating the movable base,
Furthermore, by eliminating the backlash between the guide roller attached to the guide shaft and the guide surface that is erected on the reference base and comes into contact with the guide roller by the urging force of the leaf spring member, the track tangential direction on the optical disc can be reduced. This makes accurate tilt correction possible.

[0007]

However, providing a mechanism such as a guide roller and a guide surface as in the above-described conventional apparatus causes an increase in the size of the apparatus. Further, since disturbance such as shock or vibration is applied to the apparatus, if the strength and urging force of the leaf spring member are small, plastic deformation of the leaf spring member or a fixed chassis (reference base) of the movable chassis (movable base) is performed. Separation easily occurs. Also, when the urging force of the leaf spring member is large, the load on the driving source increases due to an increase in friction at the rotating shaft portion and the driving point portion of the movable chassis,
In addition, it may cause the correction accuracy to deteriorate.

Therefore, the present invention solves the above-mentioned conventional problems, and aims at miniaturization, high-precision tilt correction, high-speed operation, and stabilization against shock or vibration in an optical disk device that performs tilt correction (tilt correction). The purpose is to:

[0009]

According to one aspect of the present invention, there is provided an optical pickup for irradiating an optical disk with a light beam for optically recording / reproducing information; A seek mechanism for sending the optical pickup in the radial direction of the optical disc, a movable chassis on which the seek mechanism is mounted and supported by a rotating shaft so as to be rotatable with respect to the fixed chassis, and An optical disc device comprising: a tilt correction driving unit that adjusts a tilt of an optical axis of a light beam emitted from the optical pickup; a spring member that biases the rotation axis toward the fixed chassis; and the tilt correction driving unit. A spring member for urging a driving point with respect to the movable chassis in the direction of the fixed chassis, and a regulating member for regulating displacement of the spring member. And then, by this configuration, for biasing the pivot shaft of the movable chassis, the spring member and the driving points for the movable chassis in inclination correction drive means,
With a simple configuration, it is possible to prevent rattling in the rotating portion and the driving portion, and furthermore, it is possible to prevent the spring member from being excessively deformed by the regulating member, so that reliable and stable tilt correction can be performed. .

According to a second aspect of the present invention, in the optical disk device of the first aspect, a screw portion is provided integrally with the regulating member, and the spring member is fixed to the fixed chassis by the screw portion. This reduces the number of parts and simplifies assembly.

According to a third aspect of the present invention, in the optical disk device according to the first aspect, the rotating shaft is pivotally supported on the fixed chassis. With this configuration, the structure for supporting the rotating shaft is simplified. And miniaturization can be achieved.

According to a fourth aspect of the present invention, in the optical disk device according to the first aspect, the spring member is formed of a leaf spring, and the biasing structure can be simplified by this configuration.

According to a fifth aspect of the present invention, in the optical disk device of the fourth aspect, a width of a portion where the leaf spring bends after contacting the regulating member is formed to be wider than a width of a portion which does not bend. Characteristically, according to this configuration, the urging force before the leaf spring contacts the regulating member can be reduced, and the urging force after the leaf spring contacts the regulating member can be increased, thereby stabilizing against impact or vibration.

According to a sixth aspect of the present invention, in the optical disk device of the fourth or fifth aspect, a portion where the leaf spring contacts the regulating member is curved in an arc shape. Can reduce the stress applied to the portion contacting the regulating member, and can prevent plastic deformation of the leaf spring.

According to a seventh aspect of the present invention, in the optical disk device of the fourth, fifth or sixth aspect, a portion where the regulating member contacts the leaf spring is formed in an arc shape.
With this configuration, the stress applied to the portion where the leaf spring contacts the regulating member can be reduced, and plastic deformation of the leaf spring can be prevented.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of an optical disk device for explaining a first embodiment of the present invention, and FIG.
FIG. 2 is a cross-sectional view taken along the line A. 1 is a spindle motor for rotating the optical disk, 2 is a fixed chassis on which the spindle motor 1 is mounted, 3 is an objective lens for condensing a light beam on the optical disk, 4 is an objective lens 3 and a lens drive. The optical pickup 5 on which the device and the optical device are mounted includes a drive motor (DC motor) 6 for feeding the optical pickup 4 in the disk radial direction, a worm gear 7 serving as a feed screw, a drive gear group 8, a guide shaft 9, and the like. Seek mechanism, 10
Is equipped with a seek mechanism 5 and fixed chassis 2 on both sides.
The movable chassis 14, which is rotatably supported by the supporting portions 12, 13 fixed to the movable chassis 10, adjusts the height of the driving point X on the driven shaft 10a extending from the central portion of one side of the movable chassis 10. This is a tilt correction mechanism.

Reference numeral 15 denotes a known inclination detecting means provided above the optical pickup 4 for detecting the inclination of an optical disk (not shown) rotated and driven by the spindle motor 1, and generally includes one light emission. In many cases, the light receiving element receives light emitted from the light emitting element and reflected from the optical disk, and when the optical disk is tilted, the difference in the amount of received light between the two light receiving elements. Is generated, and the difference in the output current due to the difference in the amount of received light is detected to detect the tilt of the optical disk.

The tilt correction mechanism 14 includes a drive cam 19 having a gear portion 18 that meshes with an output gear 17 provided on an output shaft of a drive motor (DC motor) 16, and a drive cam 19 as shown in FIG. A biasing spring member 21 is formed by a leaf spring that presses the driven shaft 10a of the movable chassis 10 disposed in contact with the upper cam surface 19a against the upper cam surface 19a. The spring member 21 is connected to the driven shaft 10
a, a vertical portion 21b having an upper portion continuous with the horizontal portion 21a, and a fixed portion 21c continuous with a lower portion of the vertical portion 21b. The fixed portion 21c is fixed to the fixed chassis 2 by screws 22. ing. Above the screw 22, a columnar regulating member 23 is provided which extends alongside the vertical portion 21b of the spring member 21.

The structures of the supporting portions 12 and 13 are as shown in FIGS. 3 to 6. FIG. 3 is a sectional view taken along line BB in FIG. 1, and FIG. 4 is a sectional view taken along line CC in FIG. FIG. 5 shows FIG.
6 is a sectional view taken along the line DD in FIG. 1, and FIG. 6 is a sectional view taken along the line EE in FIG. 1. The rotating shafts 10b and 10c protruding from both sides of the movable chassis 10 are fixed on the fixed chassis 2. The axial direction of the outer periphery makes line contact with the inner periphery of the V-shaped grooves 25a, 26a formed on the upper portions of the bearings 25, 26 so as to extend in the y direction (tangential direction of the information track on the optical disc) in FIG. Is arranged. Rotating shafts 10b, 10c
Are pressed against the inner surfaces of the V-shaped grooves 25a and 25b by biasing spring members 27 and 28, respectively. Spring member 2
7, 28 have the same configuration as the spring member 21, and have horizontal portions 27a, 28a for pressing the rotating shafts 10b, 10c, and vertical portions 27b, 2 having upper portions continuous with the horizontal portions 27a, 28a.
8b and fixing portions 27c and 28c that are continuous with the lower portions of the vertical portions 27b and 28b. The fixing portions 27c and 28c are fixed to the fixed chassis 2 by screws 29 and 30.
On the upper portions of the screws 29, 30, a columnar regulating member 3 extending alongside the vertical portions 27b, 28b of the spring members 27, 28 is provided.
1, 32 are provided.

Further, in this embodiment, in one of the support portions 13, the spring member 28 moves the end of the rotating shaft 10c in the axial direction (y
Direction), and this pressing force is applied to the movable chassis 10.
In the other support portion 12, the end of the rotating shaft 10b abuts against a stop wall portion 33 formed at the end of the V-shaped groove 25a of the bearing 25, and is positioned.

Next, the operation of the above embodiment will be described.

An inclination detecting means 15 provided above the optical pickup 4 detects an inclination of a disk surface of an optical disk (not shown) driven by the spindle motor 1. Based on this detection result, the drive motor 16 of the tilt correction mechanism 14 rotates to drive the drive cam 19 to rotate. The upper cam surface 19a of the drive cam 19 is formed such that the height in the circumferential direction of the drive point X in contact with the driven shaft 10a changes with rotation.
By adjusting the height of the optical pickup 4, the movable chassis 10 is rotated about the support portions 12 and 13, and the inclination of the optical pickup 4 with respect to the optical disk is adjusted. By this adjustment, the inclination is corrected so that the optical axis of the light beam emitted from the objective lens 3 of the optical pickup 4 is perpendicular to the optical disk.

The accuracy of the tilt correction is determined by fixing the driving point X of the driven shaft 10a and the rotating shafts 10b and 10c in the movable chassis 10 in consideration of disturbance such as shock and vibration applied to the apparatus. Chassis 2 (bearings 25, 26)
Greatly affects the position accuracy with respect to. Therefore, in the present embodiment, the driving point X of the movable chassis 10 and the rotating shaft 10
The b and 10c are biased (pressurized) against the fixed chassis 2 by spring members 21, 27 and 28, respectively, and are held.

Further, the spring members 21, 27, 28 are formed by regulating members 23, 31,
32 secures the fixed chassis 2 with screws. The regulating members 23, 31, 32 regulate the deformation and displacement of the spring members 21, 27, 28 beyond a certain level. That is, when a disturbance such as an impact is applied, the spring members 21, 27 and 28 bend and come into contact with the regulating members 23, 31 and 32,
The spring members 21, 27, 28 prevent further deformation and displacement.

The spring members 21, 27, 28 are
After coming into contact with 3, 31, 32, the portion that bends as a spring becomes shorter, so that the urging force (pressurizing force) of the spring members 21, 27, 28 changes as shown in FIG. Therefore, the spring member 2
1, 27 and 28 are hard to bend over a certain amount. Therefore, only when an impact is applied, the urging force of the spring members 21, 27, 28 can be increased, and the spring members 21, 27, 2
Even if the urging force in the step 8 is reduced, it is possible to stabilize against disturbance such as impact.

In this embodiment, the regulating members 23, 3
By screwing and fixing the spring members 21, 27, 28 with the screws 22, 29, 30 formed integrally with the components 1, 32, the number of parts can be reduced and the assembling can be simplified.

FIG. 8 is an exploded view of a spring member 21 made of a leaf spring (the other spring members 27 and 28 have the same configuration). The horizontal portion 2 which bends after the spring member 21 comes into contact with the regulating member 23 is shown.
By making the width of 1a wider than the width of the vertical portion 21b that does not bend, the change in the urging force of the spring member 21 before and after contact can be increased. Therefore, the spring member 2
1 can reduce the urging force before coming into contact with the regulating member 23 and increase the urging force after the contact, so that the inclination correction can be made more precise, faster, and stabilized against shock or vibration. it can.

FIGS. 9 to 12 are sectional views showing the structure of a supporting portion for rotatably supporting the movable chassis on the fixed chassis in the second embodiment of the present invention. Referring to the structure shown in FIG. 9 is a sectional view taken along line BB in FIG.
1 corresponds to a cross-sectional view taken along line CC in FIG. 1, FIG. 11 corresponds to a cross-sectional view taken along line DD in FIG. 1, and FIG. 12 corresponds to a cross-sectional view taken along line EE in FIG. In the following description,
Members corresponding to the members described in FIGS. 1 to 8 are denoted by the same reference numerals, and detailed description is omitted. The difference of the second embodiment from the first embodiment is the configuration of the support portions 12 and 13 for rotatably supporting the movable chassis 10 on the fixed chassis 2.

That is, in the second embodiment, the plate-like rotating shafts 10b, 10 protruding from both sides of the movable chassis 10 are provided.
1C, spherical projections 41 and 42 are formed at the lower part, a conical groove 45 is formed on one bearing 43 fixed on the fixed chassis 2, and a V-shaped groove 46 is formed on the other bearing 44 in FIG.
, And each of the spherical projections 41, 42 is formed into a conical groove 4.
5 or the V-shaped groove 46, respectively, and in the x direction in FIG.
8 and a spring member 4 having the same structure as the regulating members 31 and 32
The movable chassis 10 is fixed to the fixed chassis 2 by pressing the upper portions of the spherical projections 41 and 42 with the spring members 47 and 48, respectively.
It is rotatably supported with respect to.

As described above, the rotating shaft 1 of the movable chassis 10
0b and 10c are the pivots of the bearing 4 of the fixed chassis 2
3, 44 and the conical groove 4 of one bearing 43
When the spherical projection 41 of the one rotating shaft 10b is placed on 5, the spherical projection 42 of the other rotating shaft 10c moves in the V-shaped groove 46 of the other bearing 44 in the y direction of the V-shaped groove 46. Because of this structure, the position can be adjusted with reference to the positions of the spherical projection 41 and the conical groove 45 on one support portion 12. Therefore, even if the rotating shafts 10b and 10c are not pressed in the y-direction by the spring members 47 and 48, they are held at appropriate positions. For this reason, the degree of freedom of the mounting positions of the spring members 47 and 48 and the regulating members 49 and 50 increases.

The spring members 21, 27, 28, 4
A large stress is generated at a position where the regulating members 23, 31, 32, 49, and 50 come into contact with each other. Therefore, when a large impact is applied, the spring member may bend from a position where the spring member comes into contact with the regulating member to cause plastic deformation.

Therefore, in the present embodiment, each spring member 2
1,27,28,47,48 and regulating members 23,31,3
13, the vertical portion 27 of the spring member 27 that contacts the regulating member 31 as shown in FIG.
The portion b is bent in an arc shape. By doing so, the contact state between the spring member 27 and the regulating member 31 changes from a line contact to a surface contact, and the stress applied to the spring member 27 decreases. Plastic deformation of the spring member 27 can be prevented.

Further, as shown in FIG.
The portion where 1 contacts the spring member 27 (the tip portion in this example)
The same effect as described above can be obtained even if is curved, and the stress applied to the spring member 27 is reduced, so that plastic deformation of the spring member 27 can be prevented.

As described above, by regulating the displacement of the spring member by the regulating member as in the present embodiment, it is possible to stabilize the apparatus against disturbance such as impact. Further, by providing a screw portion integrally with the regulating member and fixing the spring member to the fixed chassis by the screw portion, the number of parts is reduced and the assembly is simplified. Further, by using a pivot as the pivot, the size of the apparatus can be reduced.

Further, by making the width of the portion that bends after the spring member made of a leaf spring comes into contact with the restricting member wider than the width of the portion that does not bend, the inclination correction can be made more accurate, speeded up, and shock or impact can be improved. Stabilization against vibration can be achieved.

Further, by bending the portion where the spring member made of a leaf spring contacts the regulating member into an arc shape, the stress applied to the portion where the spring member contacts the regulating member can be reduced, and the plasticity of the spring member can be reduced. Deformation can be prevented, and a similar effect can be obtained by making the portion where the regulating member comes into contact with the spring member an arc shape, whereby plastic deformation of the spring member can be prevented.

[0038]

As described above, according to the present invention,
The drive point and the rotating shaft of the movable chassis supporting the optical pickup and the seek mechanism can be held by the spring member without any backlash by being urged by the spring member.
Deformation is regulated by the regulating member, and tilt correction can be performed. Therefore, the number of parts can be reduced, the size of the device can be reduced, and the device can be stabilized against impact or vibration. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a plan view of an optical disc device for explaining a first embodiment of the present invention;

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a cross-sectional view taken along the line BB of FIG. 1 showing the structure of the support unit according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view taken along the line CC of FIG. 1, showing the structure of the support portion according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along the line DD of FIG. 1, showing the structure of the support portion according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view taken along the line EE of FIG. 1, illustrating a structure of a support unit according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a relationship between a spring member (leaf spring) and a pressurizing force (biasing force) according to the first embodiment of the present invention.

FIG. 8 is a plan view of a spring member according to the first embodiment of the present invention.

FIG. 9 is a cross-sectional view taken along the line BB of FIG. 1 showing a structure of a support unit according to the second embodiment of the present invention.

FIG. 10 is a cross-sectional view taken along the line CC of FIG. 1, illustrating a structure of a support unit according to the second embodiment of the present invention.

FIG. 11 is a cross-sectional view taken along the line DD of FIG. 1, showing the structure of a support according to the second embodiment of the present invention.

FIG. 12 is a cross-sectional view taken along line EE of FIG. 1, illustrating a structure of a support according to a second embodiment of the present invention.

FIG. 13 is a sectional view showing another example of the relationship between the spring member and the regulating member according to the second embodiment of the present invention.

FIG. 14 is a sectional view showing another example of the relationship between the spring member and the regulating member according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle motor 2 Fixed chassis 3 Objective lens 4 Optical pickup 5 Seek mechanism 10 Movable chassis 10a Driven shaft 10b, 10c Rotating shaft 12, 13 Support part 14 Tilt correction mechanism 15 Tilt detecting means 19 Drive cam X Drive point 21, 27 , 28, 47, 48 Spring member 22, 29, 30 Screw 23, 31, 32, 49, 50 Restriction member 25, 26, 43, 44 Bearing 25a, 26a, 46 V-shaped groove 41, 42 Spherical protrusion 45 Conical groove

Claims (7)

[Claims] An optical pickup for irradiating an optical disk with a light beam for optically recording / reproducing information, a seek mechanism for feeding the optical pickup in a radial direction of the optical disk, and the seek mechanism are mounted. A movable chassis rotatably supported by a rotating shaft with respect to the fixed chassis; and a tilt correction driving means for rotating the movable chassis to adjust a tilt of an optical axis of a light beam emitted from the optical pickup. An optical disc device comprising: a spring member for urging the rotating shaft in the direction of the fixed chassis; and a spring member for urging a drive point of the tilt correction driving unit with respect to the movable chassis in the direction of the fixed chassis. An optical disc device comprising: a regulating member that regulates displacement of a spring member. 2. The optical disk device according to claim 1, wherein a screw portion is provided integrally with said regulating member, and said spring member is fixed to said fixed chassis by said screw portion. 3. The optical disk device according to claim 1, wherein the rotating shaft is pivotally supported on the fixed chassis. 4. The optical disk device according to claim 1, wherein said spring member comprises a leaf spring. 5. The optical disk device according to claim 4, wherein a width of a portion where the leaf spring bends after contacting the regulating member is formed to be wider than a width of a portion which does not bend. 6. The optical disk device according to claim 4, wherein a portion of the leaf spring that contacts the regulating member is curved in an arc shape. 7. The optical disk device according to claim 4, wherein a portion of said regulating member that contacts said leaf spring is formed in an arc shape.