JP3480073B2 - Two axis actuator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a biaxial actuator for an optical pickup of an optical disk recording / reproducing apparatus such as an O / MD. 2. Description of the Related Art Conventionally, such a biaxial actuator for an optical pickup has been used, for example, for a CD, LD, MO, MD.
Etc. are used for recording and reproducing signals of an optical disk. The actuator moves the objective lens provided on the support member in two directions, a focusing direction and a tracking direction. [0003] Such a two-axis actuator is configured, for example, as shown in FIG. That is, in FIG. 2, the biaxial actuator 1 includes a slide base 3 supported by the reference shaft 2, a tilt adjustment plate 4 swingably attached to the slide base 3, and a tilt adjustment plate 4 on the slide base 3. XY adjustment plate 5 supported by the XY adjustment plate 5
, And an actuator cover 7 disposed to cover the lens holder 6 from the side and above. [0004] The slide base 3 is supported movably along the reference axis 2. Thereby, the objective lens 6a supported by the lens holder 6 moves along the radial direction of the optical disk. In the tilt adjusting plate 4, in the case shown in the figure, a convex portion 4 a protruding downward fits into a concave portion 3 a provided on the upper surface of the slide base 3, and the convex portion 4 a is formed inside the concave portion 3 a. Slide. Thereby, the tilt angle adjusting plate 4 is swung in an arbitrary direction with respect to the slide base 3 so that the tilt angle is adjusted. The XY adjustment plate 5 is provided on the inclination adjustment plate 4 in two horizontal directions with respect to the inclination adjustment plate 4, that is, X direction.
It is arranged movably in the Y direction. The lens holder 6 includes a suspension 6b
Are supported so as to be movable in two directions perpendicular to the direction toward the XY adjustment plate 5, ie, the tracking direction and the focusing direction. The actuator cover 7 includes an XY adjustment plate 5
And the lens holder 6
The lens holder 6 is covered from the side and above so as not to hinder the movement in the tracking direction and the focusing direction. According to the biaxial actuator 1 configured as described above, when a drive voltage is externally supplied to the drive coils provided in the lens holder 6, the magnetic flux generated in each drive coil is reduced. It interacts with the magnetic flux from the yoke and magnet (not shown) fixed and held on the XY adjustment plate 5. Thus, the objective lens 6a attached to the lens holder 6 is appropriately moved in the focusing direction and the tracking direction. However, in such a two-axis actuator adjusting device, the stroke of the lens holder 6 in the focusing direction is limited as follows. That is, the upward stroke (upward stroke) P of the lens holder 6 is limited by the contact of the upper part of the lens holder 6 with the inner surface of the actuator cover 7. Also, the lens holder 6
, The downward stroke (lower stroke) Q
Is limited by the lower part of the lens holder 6 abutting on the upper surface of the XY adjustment plate 5. As shown in FIG. 2, the position of the inner surface of the actuator cover 7 is determined by the dimension A of the slide base 3 with respect to the center of the reference shaft 2 and the dimensions B and X of the inclination adjusting plate 4.
It is determined by the dimension C of the Y adjustment plate 5 and the dimension D of the actuator cover 7. Therefore, the position of the inner surface of the actuator cover 7, that is, the upper stroke P of the lens holder 6, has a dimensional variation based on the dimensional accuracy of the dimensions A, B, C, and D of the above members. The position of the upper surface of the XY adjustment plate 5 is shown in FIG.
As shown in the figure, the dimension A of the slide base 3 with respect to the center of the reference shaft 2, the dimension B of the inclination adjusting plate 4 and the XY
Is determined by the dimension C. Therefore, the position of the upper surface of the XY adjustment plate 5, that is, the lower stroke Q of the lens holder 6, has a dimensional variation based on the dimensional accuracy of the dimensions A, B, and C of each of the above members. Thus, a relatively large variation occurs in the upper stroke P and the lower stroke Q of the lens holder 6 due to the dimensional accuracy of each member, ie, the slide base 3, the inclination adjusting plate 4, the XY adjusting plate 5, and the actuator cover 7. There was a problem. Further, the lens holder 6 is provided with the XY adjustment plate 5.
3, the inclination of the lens holder 6 is corrected by the inclination adjustment plate 4, but the lens holder 6 is fixed to the XY adjustment plate 5 and the actuator as shown in FIG. Since the lens holder 6 is inclined in the space defined by the cover 7, compared with the case where the lens holder 6 is attached to the XY adjustment plate 5 almost horizontally,
There is a problem that the upper stroke P and the lower stroke Q are each limited to a small value. In view of the above, the present invention reduces the variation in the stroke of the lens holder in the focusing direction, and limits the stroke of the lens holder even when the lens holder is installed at an angle. It is an object of the present invention to provide a two-axis actuator that does not have any problem. According to the present invention, there is provided a slide base and the slide base on the slide base.
Fixed plate fixed parallel to ride base
And the lens holder and the lens holder supported on the fixed plate
XY direction that is almost horizontal to the slide base
An adjustment plate for adjusting the orientation and / or tilt angle
Is provided so as to cover the
And an actuator cover fixed to the plate.
When the lens holder moves down,
It has a contact surface with which the lens holder comes in contact, and the fixing plate is
This is achieved by a biaxial actuator in which a portion corresponding to the contact surface of the id base is an opening . According to the above structure, the upper stroke of the lens holder is limited by the lower surface of the actuator cover.
The actuator cover is fixedly held to the slide base directly or via a fixing plate. For this reason, the position of the lower surface of the actuator cover that limits the upper stroke of the lens holder is determined by the dimensions of the slide base, the actuator cover, and the fixing plate. Therefore, the upper stroke of the lens holder is reduced in variation as compared with the case of the conventional actuator cover fixedly held on the XY adjustment plate. On the other hand, since the lower stroke of the lens holder is directly limited by the upper surface of the slide base, the position of the upper surface of the slide base that limits the lower stroke of the lens holder is determined by the dimensions of the slide base. become. Therefore, the variation in the lower stroke of the lens holder is reduced as compared with the case of the XY adjustment plate supported via the conventional tilt angle adjustment plate. Further, the stroke of the lens holder is
Since the stroke is limited by the actuator cover and the slide base, even when the lens holder is installed at an angle, the stroke of the lens holder does not become too small due to the inclination. Preferred embodiments of the present invention will be described below in detail with reference to FIG. In addition, since the Examples described below are preferred specific examples of the present invention, various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. The embodiment is not limited to these embodiments unless otherwise stated. FIG. 1 shows an embodiment of a biaxial actuator for an optical pickup of an optical disk recording / reproducing apparatus according to the present invention. In FIG. 1, a biaxial actuator 10 includes a slide base 12 supported on a reference shaft 11.
A fixed plate 13 fixedly held to the slide base 12, an adjustment plate 14 supported on the fixed plate,
A lens holder 15 supported by the adjustment plate 14 via a suspension 15b;
And an actuator cover 16 disposed so as to cover 5 from the side and above. The slide base 12 is movably supported along the reference axis 11. Thereby, the objective lens 15a supported by the lens holder 15 moves along the radial direction of the optical disc. The fixing plate 13 is fixed and held on the upper surface of the slide base 12, and has a cutout portion 13a so as not to hinder the movement of the lens holder 15 when the lens holder 15 moves downward. . The tilt angle of the adjusting plate 14 is adjusted in an arbitrary direction with respect to the upper surface of the fixed plate 13 and two directions horizontal to the upper surface of the fixed plate 13, that is, XY.
It is movably supported in the direction. The lens holder 15 includes the suspension 1
5b, it is supported so as to be movable in two directions perpendicular to each other toward the adjustment plate 14, that is, in the tracking direction and the focusing direction. The actuator cover 16 is fixed to the fixing plate 13 and the lens holder 1.
The lens holder 15 is covered from the side and above so as not to hinder the movement of the lens 5 in the tracking direction and the focusing direction. The two-axis actuator 10 according to the present invention comprises:
The drive voltage supplied from the outside to the drive coil provided in the lens holder 15 causes the magnetic flux generated in each drive coil to be fixed and held by the yoke and the magnet ( (Not shown). Thus, the objective lens 15a attached to the lens holder 15 is appropriately moved in the focusing direction and the tracking direction. The upper stroke P of the lens holder 15 is
The upper part of the lens holder 15 is the actuator cover 1
6 is limited by abutting on the inner surface. Further, the lower stroke Q is limited by the lower part of the lens holder 15 abutting on the upper surface of the slide base 12. Here, the position of the inner surface of the actuator cover 16 is, as shown in FIG. 1, the dimension A of the slide base 12 and the dimension E of the fixing plate 13 with respect to the center of the reference shaft 11.
And the dimension D of the actuator cover 16. Therefore, the position of the inner surface of the actuator cover 16, that is, the upper stroke P of the lens holder 15
Will have dimensional variations based on the dimensional accuracy of the dimensions A, E, and D of each of the above members. In the slide base 12, the position 12a where the lens holder 15 comes into contact is determined only by the dimension F of the slide base 12 with respect to the center of the reference shaft 11. Therefore, the position 12 of the slide base 12
a, that is, the lower stroke Q of the lens holder 15
Has a dimensional variation based on the dimensional accuracy of the dimension F of the slide base 12. Thus, the dimensional variation is determined by the dimensional accuracy A, D, E, F of each member, ie, the slide base 12, the fixing plate 13, and the actuator cover 16, so that the upper stroke P and the lower stroke Q of the lens holder 15 are determined. Is significantly reduced as compared with the conventional case. Further, when the lens holder 15 is mounted obliquely, the inclination of the lens holder 15 is corrected by the adjusting plate 14. However, in this case, the lens holder 15 has a stroke defined by the position 12 a of the slide base 12 and the lower surface of the actuator cover 16. Therefore, unlike before,
Even when the lens holder 15 is attached to the adjustment plate 14 at a position substantially horizontal to the upper surface of the fixed plate 13, the upper stroke P and the lower stroke Q are significantly reduced. Never. In the above embodiment, the two-axis actuator for the optical pickup of the optical disk recording / reproducing apparatus has been described.
For two-axis actuators for optical disk recording / reproducing devices such as MO and MD and optical pickups for optical disk reproducing devices
Obviously, the present invention applies. As described above, according to the present invention, the variation in the stroke of the lens holder in the focusing direction can be reduced, and even when the lens holder is mounted obliquely, the stroke of the lens holder can be reduced. Is not limited, and a two-axis actuator can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing one embodiment of a biaxial actuator according to the present invention. FIG. 2 is a schematic sectional view showing an example of a conventional biaxial actuator. FIG. 3 is a schematic view of a case where a lens holder in the biaxial actuator of FIG. 2 is attached obliquely. [Description of Signs] 10 Biaxial actuator 11 Reference axis 12 Slide base 12a Contact surface 13 Fixed plate 13a Notch 14 Adjustment plate 15 Lens holder 15a Objective lens 15b Suspension 16 Actuator cover

Continuation of front page (56) References JP-A-5-28510 (JP, A) JP-A-6-44574 (JP, A) JP-A-7-14188 (JP, A) JP-A-7-334855 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B ^7/ 08-7/085

Claims (1)

(57) [Claims 1] A slide base , and a slide base parallel to the slide base.
The fixing plate fixed in a state, the lens holder, and the lens holder supported on the fixing plate
XY directions that are substantially horizontal to the id base and / or
Is provided to cover the lens holder from the side and above, and an adjustment plate to adjust in the tilt angle direction
Actuator cover fixed to the fixing plate
And a chromatography, the slide base moves the lens holder downwards
Has an abutment surface which the lens holder when the abut, the fixing plate to correspond to the contact surface of the slide base
A two-axis actuator characterized in that an opening is formed at the part where the shaft moves .