JP2004063046A - Optical system driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturized and high performance tilt adjusting mechanism for an optical element. <P>SOLUTION: A pedestal 40 is provided with a mounting part 41 for a reflection mirror 30 and the reflection mirror 30 is bonded and fixed to the mounting part 41. The pedestal 40 is contained in the space of a carriage. At this time, the carriage is adjusted in its tilt and is attached to the pedestal 40 by using gaps 44a and 44b, so that the optical axis of an objective lens 1 on the carriage is made perpendicular to a recording medium surface. An adjusting machine is used for the adjustment. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical system driving device provided in an optical recording / reproducing device for optically recording / reproducing information.
[0002]
[Prior art]
In general, a mechanism for moving an optical element in a direction perpendicular to a recording medium adjusts the inclination of the optical element and is attached to a carriage in order to correctly direct the optical element toward the recording medium.
[0003]
In Japanese Unexamined Patent Publication No. 9-54960, as shown in FIGS. 1 and 2 of the publication, a holder 1 holding a lens 2 is supported by a leaf spring 5 on a spring receiving member 9 so as to be movable in a vertical direction of a recording medium. ing. A focus actuator 18 for moving the lens 2 in a direction perpendicular to the recording medium is mounted on a carriage 20. The carriage 20 has a groove 24 through which light passes. The focus actuator 18 is attached to the carriage 20 in such a manner that a part of the focus actuator 18 is inserted into the groove. The spring receiving member 9 of the focus actuator 18 is provided with three convex portions 13a to 13c. A rising portion 26 is formed at an end of the groove 24 of the carrier 20, and a groove 27 and a curved surface 28 are provided. The bottom surface of the groove 27 is also a curved surface, and the convex portion 13a is brought into contact with the convex portion 13b, 13c against the curved surface 28, and by shifting the same, the spring receiving member 9 can be tilted, and the focus actuator 18 can be tilted. Thus, the lens 2 can be correctly fixed and adhered to the recording medium.
[0004]
In the optical system driving device disclosed in Japanese Patent Application Laid-Open No. 9-54960, the focus actuator 1g is mounted and adjusted inside the carriage 20, so that the size of the optical system driving device such as the carriage 20 increases due to the adjustment mechanism. When the size of the optical system driving device increases, the natural frequency of the entire driving device decreases, which hinders control and results in a low-performance device.
[0005]
Therefore, as shown in FIG. 15, the carriage 201 is in contact with the shaft 200 at the bearings 202a and 202b (there are actually two shafts, but only one is shown for explanation), and the bearings 202a and 202b are separate members from the carriage 201. Then, the focus actuator (not shown in FIG. 15) on the carriage 201 can be oriented in the correct direction by performing the adjustment and the adhesive fixation to the carriage 201.
[0006]
[Problems to be solved by the invention]
However, in the case of FIG. 15, the reflection mirror 204 fixed to the reflection mirror mounting portion 203 of the carriage 201 also tilts due to the carriage 201 being tilted with respect to the axis. Light emitted from the outside of the carriage 201 is reflected by the reflection mirror 204, the direction of the reflected light path 205b changes as shown in the figure with respect to the incident light path 205b, and enters the objective lens. The angle 206 between the optical path 205a and the axis 200 needs to be a right angle, but when the carriage 201 is inclined, the angle 207 is shifted from the right angle as shown in FIG. Although the objective lens (not shown) is oriented in the correct direction, the direction of the light incident thereon is incorrect, and as a result, there is a problem that a spot cannot be correctly formed on the recording medium.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical system driving device capable of realizing a small and high-performance tilt adjusting mechanism for an optical element.
[0008]
[Means for Solving the Problems]
An optical system driving device according to an aspect of the invention includes a holder having an optical element, a carriage supporting the holder so as to be movable in a substantially vertical direction and / or a substantially radial direction of a recording medium, and the carriage having a substantially radius of the recording medium. Two shafts movably supported in the directions, a plurality of bearings provided on the carriage for supporting the two shafts, and changing directions of light rays incident on the optical element fixed to the carriage. An optical system driving device having at least a reflecting mirror for causing the bearing and the fixing portion of the reflecting mirror to be combined and fixed to the carriage separately.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0010]
1 to 6 relate to a first embodiment of the present invention, FIG. 1 is a perspective view showing an external configuration of an optical system driving device, and FIG. 2 is a perspective view showing a first main part of the optical system driving device of FIG. FIG. 3 is an exploded perspective view of a second main part of the optical system driving device of FIG. 1, and FIG. 4 is a cross-sectional view of the optical system driving device of FIG. FIG. 5 is a first diagram illustrating a method of adjusting the inclination of the optical element in the optical system driving device of FIG. 1, and FIG. 6 illustrates a method of adjusting the inclination of the optical element in the optical system driving device of FIG. It is the 2nd figure which does.
[0011]
In the optical system driving apparatus 100 of the present embodiment, as shown in FIGS. 1 to 4, the objective lens 1 and the focus coils 5a and 5b are adhered to the holder 2.
[0012]
The focus coils 5a and 5b fit the central holes into the convex portions 3a and 3b (the convex portions 3a are not shown by shadows) provided on the holder 2. Further, one ends of the leaf springs 6a and 6b are also adhered to the holder 2. The other ends of the leaf springs 6a and 6b are bonded to a spring receiver 9. The holder 2 is supported by the leaf springs 6a and 6b so as to be movable in a vertical direction (z direction) of a recording medium (not shown). This group is called a focus actuator 15.
[0013]
The focus actuator 15 is provided on a carriage 18 made of synthetic resin. The 12 surfaces of the spring receiver 9 and the surface 16 of the carriage 18 and the surfaces 13a and 13b of the spring receiver 9 are placed on the surfaces 17a and 17b of the carriage 18 (the surface 17a is shaded). (Not shown) are attached so as to be in contact with each other, and are adhesively fixed to the spring receiver 9 and the carriage 18 on the surface thereof. Further, tracking coils 32a and 32b are also adhered to the carriage 18.
[0014]
The tracking coils 32a and 32b and the focus coils 5a and 5b are connected to an electric circuit by a flexible substrate (not shown). A space 19 is provided on the back side of the carriage 18. Grooves 29a and 29b (grooves 29b are not visible in the figure) are also provided on the side surface of the carriage 18.
[0015]
As shown in FIG. 3, a nonmagnetic metal upper cover 38 is adhesively fixed so as to cover the focus actuator 15.
[0016]
As shown in FIG. 4, the bearing base 40 is made of resin, and has main bearings 42a and 42b and a driven bearing 43 formed thereon. The shapes of the main bearings 42a and 42b are the same and have a circular cross section cut at four planes as shown in FIG. 4, and the distance between the opposed planes is 5 to 5 times larger than the diameter of the shaft 33b passing therethrough. The size is increased by about 10 μm. The shape of the driven bearing 43 is a shape obtained by cutting a circular cross section by two planes as shown in FIG. 4, and the distance between the opposed planes is set to be about 5 to 10 μm larger than the diameter of the shaft 33a passing therethrough. . The mounting portion 41 of the reflection mirror 30 is provided on the bearing base 40, and the reflection mirror 30 is adhered and fixed. The bearing stand 40 is adapted to enter the space 19 of the carriage 18 (see FIG. 2).
[0017]
At this time, there are gaps 44a and 44b as shown in FIG. 4, and the carriage 18 is tilted and attached to the bearing base 40 by using the gaps 44a and 44b, and the optical axis of the objective lens 1 on the carriage 18 is shown in the figure. The recording medium is not perpendicular to the surface of the recording medium. For adjustment, use a coordinator.
[0018]
The carriage 18 is gripped by an adjusting device so that the optical axis of the objective lens 1 is perpendicular to a plane defined by the two axes with respect to the axis passed through the bearing base 40, and the inclination is adjusted. At this time, the distance between the objective lens 1 and the axis is also set to a predetermined position. At the time of adjustment, the adjuster is provided with a claw, and the adjustment is performed by grasping the grooves 29a and 29b of the carriage 18 with the claw.
[0019]
As shown in FIG. 5, the carriage 18 is tilted so as to rotate about the principal point 50 of the objective lens 1 (arrows 51 and 52). After the adjustment, the fixing is performed by bonding. At this time, the distance between the objective lens 1 and the axis is also set to a predetermined position. The center of rotation is desirably the principal point of the objective lens 1, but this does not mean that it must be different.
[0020]
For example, as shown in FIG. 6 (a cross-sectional view at the center in the Y direction), a convex portion is provided at substantially the center of the bearing base 40, and a concave portion is provided at a portion opposite to the carriage 18, so that the convex and concave portions are in contact with each other. It may be adjusted as the center. In this case, since there is a portion that is in mechanical contact, the configuration of the adjuster can be simplified.
[0021]
As shown in FIGS. 1 to 4, the shafts 33b and 33a are passed through the main bearings 42a and 42b and the driven bearing 43, respectively. Thus, the carriage 18 is supported movably in the radial direction (X direction) of the recording medium (not shown).
[0022]
Inner yokes 34a and 34b are arranged in the tracking coils 18a and 18b. Copper short rings 35a and 35b having a thickness of about 0.2 mm are attached by caulking to the outside of the inner yokes 34a and 34b. The outer yokes 36a, 36b are located in the z-ten direction of the inner yokes 34a, 34b. Magnets 37a, 37b are adhesively fixed to the outer yokes 36a, 36b. The shafts 33a and 33b and the inner yokes 34a and 34b are fixed to a deck base (not shown). The outer yokes 36a and 36b are fixed to a deck base (not shown) via the inner yokes 34a and 34b.
[0023]
Next, the operation of the present embodiment configured as described above will be described.
[0024]
Laser light emitted from a fixed optical system (not shown) passes through the opening 23 of the carriage 18 and the opening 4 of the holder (see FIG. 2), is reflected by the reflection mirror 30, and is then reflected by the objective lens 1. A spot is formed on a recording medium not shown. The reflected light from the recording medium returns to the fixed optical system through the objective lens 1 again, and a focus error, a tracking error, and a recording signal are detected. When a focus error is detected, the current is applied to the focus coils 5a and 5b to drive the holder 2 in a direction perpendicular to the medium surface. When a tracking error is detected, the holder 2 is driven together with the carriage 18 in the radial direction of the medium by passing a current through the tracking coils 32a and 32b. When accessing a different track, the holder 2 is driven together with the carriage 18 in the radial direction of the medium so that current flows through the tracking coils 32a and 32b.
[0025]
As described above, the focus control, the tracking control, and the access control of the holder 2 and the objective lens 1 fixed thereto are performed.
[0026]
In the present embodiment, as described above, since the tilt adjustment of the objective lens 1 is performed between the bearing base 40 and the carriage 18, it is not necessary to provide a tilt adjusting mechanism between the spring receiver 9 and the carriage 18. The spring receiver 9 and its part. The shape of the ridge 18 can be simplified, and these can be reduced in size. In addition, since the reflection mirror 30 is fixed to the bearing base 40, by adjusting the inclination, the direction of the reflection mirror 30 does not deviate from a predetermined direction, and good recording / reproducing characteristics can be obtained.
[0027]
The bearing cross section shown in the present embodiment is an example, and for example, the main bearing shape may be a simple circular cross section. In the present embodiment, the tracking single-stage servo system is used, but it goes without saying that the tracking two-stage servo system is also effective.
[0028]
7 to 12 relate to a second embodiment of the present invention, FIG. 7 is a perspective view showing an external configuration of an optical system driving device, FIG. 8 is a perspective view of a main part of the optical system driving device in FIG. 9 is an exploded perspective view of a main part of the optical system driving device of FIG. 7, FIG. 10 is a first diagram illustrating a method of adjusting the inclination of an optical element in the optical system driving device of FIG. 7, and FIG. FIG. 12 is a second diagram illustrating a method of adjusting the inclination of the optical element in the optical system driving device, and FIG. 12 is a third diagram illustrating a method of adjusting the inclination of the optical element in the optical system driving device of FIG.
[0029]
Since the second embodiment is almost the same as the first embodiment, only different points will be described, and the same components will be denoted by the same reference numerals and description thereof will be omitted.
[0030]
In the optical system driving device 100a of the present embodiment, as shown in FIGS. 7 to 9, the objective lens 1 and the focus coils 5a and 5b are adhered to the holder 2.
[0031]
Further, one ends of the leaf springs 6a and 6b are also adhered to the holder 2. The other ends of the leaf springs 6a and 6b are bonded to the carriage 18a. The holder 2 is supported by the leaf springs 6a and 6b so as to be movable in a vertical direction (Z direction) of a recording medium (not shown). Covers 51a and 51b and tracking coils 32a and 32b are also adhesively fixed to the carriage 18a. Although not shown, the focus coils 5a and 5b and the tracking coils 32a and 32b are connected to an external electric board by a flexible board.
[0032]
Spaces 52, 53, and 54 are provided in the carriage 18a, and main bearings 42a and 42b and a driven bearing 43 are adhesively fixed to the spaces. The cross-sectional shape of each bearing is the same as in the first embodiment.
[0033]
The mounting portion 41 of the reflection mirror 30 is provided integrally with the main bearing 42a, and the reflection mirror 30 is fixed. In the assembly, first, a member in which the mounting portion 41 of the reflection mirror 30 and the main bearing 42a are integrated is bonded and fixed to the carriage 18a. At this time, the optical axis of the objective lens 1 on the carriage 18a is perpendicular to the center axis of the shaft 33b passing through the main bearing 42a. The angle A in FIG. The main bearing 42a and the reflection mirror 30 fixed to the mounting portion 41 of the reflection mirror 30 need to be integrally formed precisely at a correct angle (45 degrees).
[0034]
Next, the driven bearing 43 is adhesively fixed to the carriage 18a. Since the angle B in FIG. 11 changes depending on the position of the driven bearing 43, the angle B is adjusted so as to be 90 degrees. Further, the axis 33b passing through the main bearing 42a and the axis 33a passing through the driven bearing 43 are made parallel. Thus, the optical axis of the objective lens 1 is perpendicular to the plane determined by the axes 33a and 33b. Finally, the main bearing 42b is bonded and fixed to the carriage 18a such that the center of the main bearing 42a coincides with the center of the main bearing 42a (so that the shaft 33a passes).
[0035]
It should be noted that, as shown in FIG. 12, a spherical surface 57 centered on the principal point 50 of the objective lens 1 is provided on a member in which the mounting portion 41 of the reflection mirror 30 and the main bearing 42a are integrated, and a spherical surface 56 having substantially the same radius as the carriage is provided. When the member provided with the mounting portion 41 of the reflection mirror 30 and the main bearing 42a is fixed to the carriage 18a, the spherical portion may be adjusted by shifting the member. As a result, a portion where the two members are in contact with each other is formed, so that the adjustment is facilitated, the configuration of the adjuster can be simplified, and the rigidity of the carriage 18a can be increased. Other configurations and operations are the same as those of the first embodiment.
[0036]
As described in the first embodiment, the bearing is only 5 to 10 μm larger than the shaft, and if the two main bearings 42a and 42b have poor coaxiality, the bearing does not move on the shaft. The difficulty of resin molding for obtaining this accuracy is also high. In the present embodiment, since the adjustment is made when fixing this to the carriage 18a, it is not necessary to increase the coaxiality, and the molding cost of the bearing can be reduced.
[0037]
Further, in this embodiment, the cost for the spring receiver can be reduced by directly attaching the leaf springs 6a and 6b to the carriage 18a without using the spring receiver.
[0038]
13 and 14 relate to a third embodiment of the present invention. FIG. 13 is an exploded perspective view of a main part of the optical system driving device, and FIG. 14 is a cross-sectional view showing a cross section of the main part of FIG.
[0039]
Since the third embodiment is almost the same as the second embodiment, only different points will be described, and the same components will be denoted by the same reference numerals and description thereof will be omitted.
[0040]
As shown in FIGS. 13 and 14, in the present embodiment, the main bearings 42 a and 42 b and the driven bearing 43 are bonded and fixed as in the second embodiment, but the mounting portion between the main bearing 42 a and the reflection mirror 30 is attached. 41 is not integrated. The mounting portion 41 is a separate body, and is provided with a spherical portion 61 and a convex portion 64. The carriage 18b is provided with a spherical portion 65 and a hole 66. The spherical portion 61 and the spherical portion 65 are assembled so that the convex portion 64 enters the hole 66 so that the spherical portion 65 is in contact with the spherical portion 65.
[0041]
First, the main bearings 42a and 42b and the driven bearing 43 are adhesively fixed to the carriage 18b such that the optical axis of the objective lens 1 is perpendicular to the recording medium surface (not shown). At this time, the main bearings 42a and 42b are also adjusted so that they are on the same axis (so-called coaxiality is obtained). After that, the inclination is adjusted by grasping the convex portion 64 so that the reflection mirror 30 is oriented in the correct direction, and is adhesively fixed. The center of the spherical portion is desirably the principal point of the objective lens 1, but may be located at a point shifted from that point.
[0042]
In the present embodiment, since it is not necessary to worry about the direction of the reflection mirror 30 when attaching the main bearing 42a, the adjustability can be improved and the adjustment amount can be increased. Also, the accuracy of the parts can be reduced. As a result, the cost of parts can be further reduced.
[0043]
The present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the spirit of the present invention.
[0044]
【The invention's effect】
As described above, according to the present invention, there is an effect that a small-sized and high-performance tilt adjusting mechanism for an optical element can be realized.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external configuration of an optical system driving device according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view of a first main part of the optical system driving device in FIG. FIG. 4 is an exploded perspective view of a second main part of the optical system driving device of FIG. 1; FIG. 4 is a cross-sectional view showing a cross section taken along line AA in a yz plane including an objective lens of the optical system driving device of FIG. 1 is a first diagram illustrating a method of adjusting the inclination of an optical element in the optical system driving device of FIG. 1. [FIG. 6] A second diagram illustrating a method of adjusting the inclination of an optical element in the optical system driving device of FIG. FIG. 7 is a perspective view showing an external configuration of an optical system driving device according to a second embodiment of the present invention. FIG. 8 is a perspective view of a main part of the optical system driving device shown in FIG. FIG. 10 is an exploded perspective view of a main part of a system driving device. FIG. 10 is a first diagram illustrating a method of adjusting the inclination of an optical element in the optical system driving device of FIG. FIG. 12 is a second diagram illustrating a method of adjusting the inclination of the optical element in the optical system driving device of FIG. 7; FIG. 12 is a third diagram illustrating a method of adjusting the inclination of the optical element in the optical system driving device of FIG. 13 is an exploded perspective view of a main part of an optical system driving device according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view showing a cross section of the main part of FIG. 13. FIG. FIG. 16 is a first diagram illustrating a method of adjusting the inclination of an optical element. FIG. 16 is a second diagram illustrating a method of adjusting the inclination of an optical element in a conventional optical system driving device.
DESCRIPTION OF SYMBOLS 1 ... Objective lens 2 ... Holder 3a, 3b ... Convex part 5a, 5b ... Focus coil 6a, 6b ... Leaf spring 9 ... Spring receiver 15 ... Focus actuator 18 ... Carriage 30 ... Reflection mirror 32a, 32b ... Tracking coil 40 ... Bearing stand 41 mounting parts 42a, 42b main bearing 43 driven bearings 44a, 44b gaps 29a, 29b groove 100 optical system driving device

Claims (3)

A holder with an optical element,
A carriage supporting the holder so as to be movable in a substantially vertical direction and / or a substantially radial direction of a recording medium;
Two shafts for supporting the carriage so as to be movable in a substantially radial direction of the recording medium;
A plurality of bearings provided on the carriage to support the two shafts;
An optical system driving device having at least a reflecting mirror for changing a direction of a light beam incident on the optical element fixed to the carriage,
An optical system driving device, wherein the bearing and the fixed portion of the reflection mirror are fixed to the carriage separately as a unit. A holder with an optical element,
A carriage supporting the holder so as to be movable in a substantially vertical direction and / or a substantially radial direction of a recording medium;
Two shafts for supporting the carriage so as to be movable in a substantially radial direction of the recording medium;
A plurality of bearings provided on the carriage to support the two shafts;
An optical system driving device having at least a reflecting mirror for changing a direction of a light beam incident on the optical element fixed to the carriage,
A part or all of the bearings are fixed to the carriage as a separate body from the carriage, and one of the bearings is fixed to the carriage as a separate body in a form in which the bearing and a fixed portion of the reflection mirror are combined. Optical system drive. A holder with an optical element,
A carriage supporting the holder so as to be movable in a substantially vertical direction and / or a substantially radial direction of a recording medium;
Two shafts for supporting the carriage so as to be movable in a substantially radial direction of the recording medium;
A plurality of bearings provided on the carriage to support the two shafts;
An optical system driving device having at least a reflecting mirror for changing a direction of a light beam incident on the optical element fixed to the carriage,
An optical system driving device, wherein a part or all of the bearings are fixed to the carriage as a separate body from the carriage, and a fixing portion of the reflection mirror is fixed to the carriage as a separate body.

Images