JP2861950B2 - Optical head lens optical axis adjusting device - 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 axis adjusting device for an objective lens used in an optical head of an optical disc device.

[0002]

2. Description of the Related Art Research on an external storage device having both the high-speed accessibility of a magnetic disk for a computer and the large-capacity memory of an optical disk is progressing rapidly. The development will continue in the direction of higher density and higher recording rate.
For this purpose, it is necessary to increase the numerical aperture (NA) of the objective lens provided in the optical head and shorten the laser wavelength. When Ru with a large lens of NA, tilt margin is reduced with respect to the optical axis inclination and the optical disc recording surface tilt of the objective lens. For this reason, a device for easily and accurately adjusting the optical axis of the objective lens is required.

FIG. 7 shows a schematic configuration of an optical head which requires an optical axis adjustment. The optical disk 10 has a recording surface directed downward, and the optical disk 10 is radially positioned at a position facing the recording surface. A slide shaft 12 for guiding a book is extended. And a fixed optical system 1 having a built-in light source, light receiving element, and the like.
3 is installed at one end position of the slide shaft 12,
The movable optical system 1 optically coupled to the fixed optical system 13
4 is the optical disk 10 along the slide shaft 12
Are supported so as to be able to reciprocate in the radial direction.

As shown in FIG. 8, the movable optical system 13 has a built-in 45-degree mirror 23 and an objective lens 24, and the light transmitted from the fixed optical system 13 in the direction in which the slide shaft 12 extends. Is reflected upward by the 45-degree mirror 23, and is imaged on the recording surface of the optical disk 10 by the objective lens 24. The reflected light from the optical disk 10 is transmitted to the fixed optical system 13 via the objective lens 24 and the 45-degree mirror 23. The objective lens 24 is supported by an adjustable actuator 40,
By adjusting the attitude of the actuator 40, the optical axis of the objective lens 24 is adjusted in the radial and tangential directions of the optical disk. In the example shown in FIG. 8, an inclination adjusting section 41 composed of a spring washer and a screw is provided below the actuator 40 for adjustment.

An actuator for adjusting the optical axis of the objective lens is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-31195.
There is one described in Japanese Patent Publication No. As shown in FIG. 9, the housing 100 has a width Wr in the radial direction of the optical disc smaller than the width Wt in the tangential direction of the optical disc.
And an actuator holder 101 which houses the housing 100. The abutment between the spherical lower surface 102 of the housing 100 and the spherical inner surface 103 of the actuator holder 101 supports the housing 100 so that the housing 100 can move spherically. I have. In the housing 100, an objective lens 106 is supported by a four-wire objective lens actuator 105. Therefore,
A beam incident from below the actuator holder portion (not shown) is collected by the objective lens 106 into 100
While observing with a 0 × microscope and monitoring the uniformity of the primary fringe shape of the focused beam, the posture of the housing 100 is adjusted to an optimum angular position, and after the adjustment, the ultraviolet adhesive is applied to the groove 107 in the holder 101. To fix the two, it is possible to adjust and set the optical axis in the radial and tangential directions of the optical disk.

[0006]

In such a conventional optical axis adjusting apparatus, when adjusting the optical axis of the objective lens, it is necessary to adjust the optical axis from the recording surface side of the optical disk or the tangential direction of the optical disk. And it was. For example, in the configuration example of FIG. 8, it is necessary to adjust the screw of the tilt adjustment unit provided below the actuator from below. Further, in the configuration example of FIG. 9, it is necessary to adjust the inclination of the housing by inserting a jig from each of the tangential direction and the radial direction of the optical disk.
However, since a flexible substrate and a recording / reproducing amplifier are usually arranged on the lower surface of the optical head, it is difficult to adjust the rotation with a screwdriver or the like. Further, in the operation from the tangential direction of the optical disk, since the slide shaft for supporting the movable optical system and the linear motor as the driving source are arranged, the adjustment work from this direction becomes difficult. For this reason, conventionally, it is almost impossible to adjust the optical axis while assembling various components in the optical disk device or while actually operating the optical head, and it is difficult to perform high-precision optical axis adjustment. is there.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical axis adjusting apparatus which can easily adjust the optical axis of an objective lens and can also perform the recording and reproducing with respect to an optical disk.

[0008]

According to the present invention, there is provided a lens optical axis adjusting apparatus for an objective lens which is provided in a movable optical system which is moved in a radial direction with respect to an optical disk and forms an image on a recording surface of the optical disk. An optical axis adjusting means for adjusting the optical axis in a radial direction and a tangential direction of the optical disk is provided.
As the configuration of the optical axis adjusting means, an actuator base holding an objective lens is elastically supported on the casing by a spring material such that the actuator base can be tilted at least in a radial direction and a tangential direction of the optical disc in a casing of the movable optical system. The tip ends of a plurality of adjustment screws supported by the casing are abutted on different portions of the actuator base, and the screwing positions of these adjustment screws are changed to adjust the tilt angle of the actuator base. Is done. In this case, the actuator base has three different plane directions.
Adjustment walls are erected at the points and holes are formed in each adjustment wall, and each adjustment screw is screwed into the casing,
And the taper part provided in each front-end | tip part is made into the structure eccentrically contacted with each hole, and the screwing position of the said adjustment screw
Between the taper portion of the adjusting screw and each of the holes.
The adjusting wall is raised by the vertical force generated by the contact force.
It is configured to be moved in the vertical direction.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of an optical head according to the present invention, and FIG. 2 is a front view of the optical head viewed from an optical axis direction. A disk motor 11 for rotating the optical disk is provided in the optical disk device, and the optical disk 10 is mounted on the disk motor with its recording surface facing downward. Also, a pair of slide shafts 12 are provided on one side of the disk motor 11 along the radial direction of the optical disk, and a fixed optical system 13 is provided at a position on the distal end side of the slide shaft 12. A movable optical system 14 is supported on the slide shaft 12 so as to be able to reciprocate. The fixed optical system 13 includes a laser diode 15 serving as a light source, a lens 16 and mirrors 17 and 18 for projecting a laser beam emitted from the laser diode 15 as a light beam to the movable optical system, and a movable optical system. A lens 19 and a photodiode 20 for receiving the laser beam are provided.

The movable optical system 14 is a movable casing 2
The movable casing 21 is provided with a slide bearing 22 for reciprocating on the slide shaft 12. In the movable casing 21, a 45-degree mirror 23 and an objective lens 24 for forming a laser beam from the fixed optical system 13 on the optical disc 10 or transmitting the reflected light to the fixed optical system 13 are provided. Provided. The 45-degree mirror 23 is provided in the radial direction of the optical disc 10,
2 of the movable casing 21 along the direction of extension of the side wall 2
The laser beam is fixed in the movable casing 21 in a state where the laser beam is inclined 45 degrees in the vertical direction with respect to a laser beam window 25 provided in the laser beam window 1a. Is reflected in a direction substantially perpendicular to the recording surface of the optical disk 10.

On the other hand, the objective lens 24 is supported in the movable casing 21 by an actuator base 27 and a lens holder 28 supported by a leaf spring 26, and a laser beam directed vertically by the 45-degree mirror 23. Are arranged substantially horizontally so as to form an image on the recording surface of the optical disk 10. The leaf spring 26
3 is fixed to the bottom surface of the movable casing 21 at a central portion 26a as shown in FIG.
The arm portions 26b to 26d are connected to the bottom surface of the actuator base 27. As a result, the actuator base 27 is elastically supported in the movable casing 21, and the actuator base 27 is elastically deformed in each of the arms 26 b to 26 d of the leaf spring 26 so that the actuator base 27 can be appropriately moved in an arbitrary vertical direction with respect to the bottom surface of the movable casing 21. It is configured to be tiltable in the angle range. The lens holder 28 is supported by the actuator base 27 with four wires (not shown), and the objective lens 24 is held by the lens holder 28 directly above the 45-degree mirror 23. . Thus, the objective lens 24 can be tilted integrally with the actuator base 27.

As shown in a perspective view of the main part in FIG. 4, the actuator base 27 has adjusting walls 29a to 29c at three different plane positions so as to face the one side wall 21a of the movable casing 21, respectively. And the adjusting walls 29a to 29c have holes 30a to 3 having a required diameter, respectively.
0c is provided. Further, screw holes 31a to 31c are formed in the one side wall 21a of the movable casing 21 at positions facing the respective adjustment walls.
Screws (hereinafter referred to as needle screws) 32a to 32c each having a tapered tip at its tip are screwed into each of the adjustment walls a to 31c.
c. Here, each needle screw 32
Because the same length is used for a to 32c,
A recess 21b is formed in a part of one side wall 21a facing the adjustment wall 29b, and the screw hole 31b is provided in a wall surface of the recess 21b. The screw holes, in other words, the needle screws 32a to 32c
a at the same height position.

Further, holes 30a to 30c of the respective adjusting walls are provided.
The center of the needle screw is provided at a position slightly displaced in the direction perpendicular to the axis of the needle screws 32a to 32c, and has a diameter substantially equal to the diameter of the tip of the needle screw. Therefore, each of the needle screws 32a to 32
c, the tapered portion at the tip of the needle screw enters the holes 30a to 30c. At this time, the axes of the two are displaced, so that the adjusting wall 29a is displaced.
29c are moved in the vertical direction by the wedge action of the tapered portion, whereby the actuator 27 can be tilted in the vertical direction.

According to this configuration, when adjusting the optical axis of the objective lens, as shown in FIG. 5, the three needle screws 3 screwed and arranged on one side wall 21a of the movable casing 21 are used.
The rotation of 2a to 32c is adjusted by a tool such as a screwdriver. As a result, each needle screw is screwed into one side wall of the movable casing 21, and the tapered portion at the tip of the needle screw contacts the holes 30 a to 30 c of each adjustment wall of the actuator base 27 in the screw axis direction. Be retired. As a result, the adjustment walls 29a to 29c of the actuator base 27 are moved in the vertical direction, and the actuator base 27 itself is tilted in the vertical direction. In this case, for example, by fixing the needle screw 32a, the adjustment wall 29a is used as a fulcrum, and by adjusting the needle screw 32c and the adjustment wall 29c that are opposed to the adjustment wall 29a in the tangential direction of the optical disk, the actuator base is adjusted. 27 is tilted in the tangential direction of the optical disk 10. The adjustment wall 29 as a fulcrum
The actuator base 27 is tilted in the radial direction of the optical disk 10 by adjusting the needle screw 32b and the adjustment wall 29b located substantially in the radial direction of the optical disk 10 with respect to a. Accordingly, with the tilting of the actuator base 27, the optical axes of the objective lens 24 and the lens holder 28 held by the actuator base are adjusted in the tangential direction and the radial direction of the optical disk 10.

As described above, in this optical axis adjusting device, the optical axis of the objective lens 24 is adjusted in the tangential direction and the radius of the optical disk 10 by performing the adjusting operation on the one side wall 21a of the movable casing 21 of the movable optical system 14. The adjustment can be made in any of the directions. Therefore, there is no need to make adjustments from the bottom surface side of the optical disc device or from the tangential direction of the optical disc device. Even when various components are arranged at the bottom position of the optical disc device, or when reciprocating through the movable optical system. The optical axis of the objective lens can be adjusted even when the moving bearing is provided in the tangential direction of the optical disk. Further, since the optical axis adjustment can be performed by utilizing the space between the pair of slide shafts 12, unless the laser beam between the fixed optical system 13 and the movable optical system 14 is blocked, the movable optical system The optical axis can be adjusted with extremely high accuracy even when recording and reproducing are performed.

The adjustment wall provided on the actuator base can be arranged as shown in FIG. In this case, the adjustment wall 29a 'can be used as a fulcrum, and the adjustment wall 29c' can adjust the optical axis in the optical disk radial direction, and the adjustment wall 29b 'can adjust the optical axis in the tangential direction of the optical disk. The planar arrangement of these adjustment walls and the contact position of the needle screw with respect to each adjustment wall are not limited to the configuration of the above-described embodiment, and can be appropriately changed.

Further, in the above embodiment, the optical system is applied to the configuration in which the fixed optical system and the movable optical system are separated from each other, but the entire optical system is moved in the radial direction with respect to the optical disk. The present invention can be similarly applied to the optical head described above.

[0018]

As described above, the present invention provides a structure of an optical axis adjusting means for adjusting the optical axis of an objective lens for recording / reproducing on an optical disk in the radial direction and the tangential direction of the optical disk. In a casing of the movable optical system, an actuator base for holding the objective lens is elastically supported by the casing so as to be tiltable at least in a radial direction and a tangential direction of the optical disc by a spring material, and the tip of a plurality of adjustment screws supported by the casing Parts are abutted on different parts of the actuator base,
Changing the screwing position of the adjusting screw is configured to adjust the tilting angle of the actuator base, the further
The actuator base has three different
Adjustment walls are erected at each location and each adjustment wall is
A hole is formed and each adjustment screw is screwed into the casing
And the tapered part provided at each tip is
The holes are eccentrically contacted with the holes, and the adjusting screw
Between the taper portion of the adjusting screw and each of the holes.
The adjusting wall is raised by the vertical force generated by the contact force.
Move the actuator base in the vertical direction and tilt the actuator base.
Since the angle is adjusted, the optical axis of the objective lens can be adjusted in the tangential direction and the radial direction of the optical disk by adjusting the adjusting screw. This makes it possible to reduce the size and weight of the object for which the optical axis adjustment is performed, and it is possible to extremely easily adjust the optical axis of the actual optical head, and the optical head performs recording and reproduction on the optical disk. The optical axis can be adjusted in this state, and highly accurate optical axis adjustment can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a plan configuration of a main part of an optical head of the present invention.

FIG. 2 is a diagram showing a front configuration of FIG. 1;

FIG. 3 is a plan view of a leaf spring.

FIG. 4 is a perspective view showing a relationship between an adjustment wall of an actuator base and a needle screw.

FIG. 5 is a schematic perspective view for explaining an optical axis adjustment operation.

FIG. 6 is a plan view showing a modification of the movable optical system according to the present invention.

FIG. 7 is a schematic perspective view for explaining a configuration of a general optical head.

FIG. 8 is a schematic side view for explaining an example of a conventional optical axis adjusting device.

FIG. 9 is a perspective view for explaining another example of the conventional optical axis adjusting device.

[Explanation of symbols]

 Reference Signs List 10 optical disk 11 disk motor 12 slide shaft 13 fixed optical system 14 movable optical system 15 laser diode 20 photodiode 21 movable casing 23 45 degree mirror 24 objective lens 26 leaf spring 27 actuator base 29a-29c adjustment wall 30a-30c hole 32a-32c Needle screw

Claims (2)

(57) [Claims] 1. An optical head comprising: an objective lens for forming an image on a recording surface of an optical disc; and a movable optical system moved in a radial direction with respect to the optical disc.
The movable optical system includes optical axis adjustment means for adjusting the optical axis of the objective lens in the radial direction and the tangential direction of the optical disc, and the optical axis adjustment means is provided in a casing of the movable optical system. A spring material is used to tilt the optical disk at least in the radial and tangential directions.
Wherein it is elastically supported on the casing Te and actuator base for holding the objective lens, and a plurality of adjusting screws which its distal end is supported by the casing is in contact with the different portions of the actuator base, before
The actuator base has three locations in different plane directions.
Adjustment walls are erected and holes are provided in each adjustment wall.
Formed and said each adjustment screw is screwed into said casing
And the tapered portion provided at each tip portion is
It is abutted against each hole in an eccentric state, and the screwing position of the adjustment screw is adjusted.
Change the contact between the tapered portion of the adjusting screw and each of the holes.
The adjusting wall is raised by the vertical force generated by the force.
An apparatus for adjusting a lens optical axis of an optical head, characterized in that the tilt angle of the actuator base is adjusted by moving the actuator base in a plane direction . 2. One adjusting wall is opposed to one adjusting wall in a radial direction of the optical disk.
2. The apparatus according to claim 1 , wherein the two adjusting walls are opposed to each other in a tangential direction of the optical disk.