JPH1027352A - Optical head and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the variation of performance and to make an optical head small in size, thin in thickness and low in cost. SOLUTION: An objective lens 1 is mounted on an objective lens holder 2 previously attached with a coil to be assembled as a movable part, and a support part 3 is attached to the movable part and a hold part 4. The support part 3 attached to the movable part and the hold part 4 is joined with a yoke part 5 having a magnet provided with positioning holes 5b, 5d capable of chucking to a tilt correction mechanism for the optical axis of the objective lens 1 to be chucked to the tilt correction mechanism. The drive center of the turntable of the tilt correction mechanism is arranged so as to come to the main point position of the objective lens to be stuck to an opto-base 6 beforehand attached to a reference position after tilt correction for the optical axis is performed. Thus, by providing no tilt correction mechanism on the yoke part and the opto-base 6, the optical head can be made small in size, thin in thickness and low in cost, and the variation of distance between gaps related to the drive performance of the objective lens is suppressed by eliminating an effect when the tilt is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical head used for an optical pickup device such as an optical recording / reproducing device and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, an optical head is used in an optical recording / reproducing apparatus or the like for condensing light emitted from a light source such as a laser on a recording medium and recording / reproducing information.

FIG. 3 is a sectional view showing an example of an optical head according to the prior art. Referring to FIG. 3, the objective lens 1 is held by an objective lens holder 2, and the objective lens holder 2 is held by a holding member 4 by a support member 3 composed of a leaf spring or the like. A movable coil and a yoke section (not shown) are provided integrally with the objective lens holder 2 to constitute an actuator section for driving the objective lens 1 in a focus direction and a tracking direction as shown by arrows.

The light emitted by a light source such as a laser is
The light is focused on the recording medium 10 by the objective lens 1. At this time, if the objective lens 1 is inclined with respect to the optical axis 11,
Problems such as deterioration of light condensing property and occurrence of aberration occur. For this reason, the inclination of the objective lens 1 with respect to the optical axis 11 needs to be corrected.

In the optical head shown in FIG. 3, a tilt correcting mechanism is used to correct the tilt of the objective lens 1. This tilt correction mechanism is a plate 1 for tilt correction.
3, the end face of the opt base 14, the spring 15, the screw 16,
And a tilt correcting screw 17. The tilt correcting plate 13 has a spherical surface centered on the principal point position 12 of the objective lens, and this spherical surface is in contact with the end surface of the opt base 14. These inclination correcting plates 13
The opt base 14 is provided with a screw 16 having a spring 15 at one end. At the other end, an inclination correcting screw 17 is provided. With this tilt correction mechanism,
When the inclination is corrected, the screw 16 is used as an action point, and the screw 17 for correcting the inclination is turned, whereby the inclination correction plate 13 is rotated without causing the center deviation according to the principle of leverage, and the accompanying objective lens holder is used. 2 can correct the inclination of the objective lens 1 above.

FIG. 4 is an exploded perspective view showing another example of the conventional optical head. As shown in FIG. 4, the optical head comprises an objective lens 1 and driving coils 2a, 2a.
b or an objective lens holder 2 on which a magnet is mounted, a support member 3, a holder 4, a holder arm 7, a yoke 8 on which a magnet 8a is mounted, and an opt base 9. To correct the tilt during assembly, the opt base 9
The yoke part 8 is attached in advance, and the objective lens 1, the objective lens holder 2 on which the driving coil or magnet is mounted, the support member 3, and the holder 4 are attached to the holder arm 7.
Further, the chucking is performed on the equipment mechanism for inclination correction, without touching the yoke portion 8.

[0007]

However, in the conventional optical head shown in FIG. 3, since the ball seat is provided at a position distant from the principal point of the objective lens in the thickness direction, the tilt correction is movable. Considering the amount, it is difficult to reduce the thickness, and furthermore, there is a disadvantage that it is disadvantageous to lower the cost due to the cost of processing because of the provision of the ball seat.

In the conventional optical head shown in FIG. 4, a yoke portion to which a magnet is attached is fixed, and a holding arm on which one driving coil is mounted is gripped to correct the tilt of the objective lens. The gap between the drive coil and the magnet has an additional variation due to the influence of the inclination correction on the assembly accuracy, and the gap between the drive coil and the magnet constituting the magnetic circuit has a large variation. It had.

Furthermore, in the conventional optical head shown in FIG.
Considering mechanical interference with the yoke portion 8 and miniaturization, the contact area of the holding arm 7 is unfavorably large, and conversely, there is a demerit that the shape becomes larger when stability is further required. Was. Furthermore, when chucking or fixing the holder arm to the equipment-side mechanism for tilt correction, it tends to be unstable, difficult to adjust, and it is difficult to obtain a high-quality optical head. It had.

Therefore, one technical problem of the present invention is to reduce the size
Provides an optical head that is advantageous in weight reduction, improves productivity by adopting a shape suitable for automation, has a shape that is easy to process, and reduces costs by reducing the number of parts and a method of manufacturing the same. Is to do.

Another object of the present invention is to provide an optical pickup using the optical head.

[0012]

In order to solve the above-mentioned technical problems, an optical head according to the present invention uses an optical head for reading or writing information on a recording medium. An actuator for driving the optical axis of the objective lens to be focused on the optical axis in a plane including the optical axis; and a base supporting the actuator, wherein the actuator comprises the objective lens and the movable coil. A movable portion on which the movable portion is mounted, a support portion for movably supporting the movable portion, a holding portion for holding the support portion, and a yoke portion for applying a magnetic field to the movable coil. It is characterized by being fixed by joining.

In the optical head according to the present invention, in the optical head, the connection between the yoke portion and the base portion is performed by welding or bonding after correcting the inclination of the objective lens with respect to the optical axis. It is characterized by:

In the method of manufacturing an optical head according to the present invention,
In a method of manufacturing an optical head for reading or writing information on a recording medium, a movable section having an objective lens for focusing light on the recording medium, a supporting section for movably supporting the movable section, and a yoke. While assembling and holding the actuator unit with the unit and supporting the base,
The tilt of the objective lens with respect to the optical axis is corrected by moving the actuator relative to the base, and then the yoke is joined to the base.

In the method of manufacturing an optical head according to the present invention,
In the method of manufacturing an optical head, the base and the yoke are joined by welding or bonding.

Further, an optical pickup device according to the present invention is characterized in that the optical head is provided with the optical head.

[0017]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an exploded perspective view showing an optical head according to an embodiment of the present invention. FIG. 2 is a partial side sectional view used for explaining the assembly of the optical head of FIG.

Referring to FIGS. 1 and 2, the optical head comprises:
It forms a part of an optical pickup device, and includes a movable part having an objective lens 1, an objective lens holder 2 for holding the objective lens 1, and movable coils 2a and 2b incorporated in the objective lens holder 2. The inside of the movable coil 2b of the objective lens holder 2 is a hollow portion 2 penetrating in the vertical direction.
d, and a cavity 2e is provided on the side of the objective lens 1 of the movable coil 2a. Further, from the side opposite to the objective lens 1 side of the objective lens holder 2, a support portion 3 made of a leaf spring extends in the horizontal direction, and its tip reaches the inside of the box-shaped holding portion 4.

The yoke portion 5 includes yoke pieces 5c, 5c erected on the yoke main body 5b and a permanent magnet 5a joined to one of the center sides of the yoke pieces 5c, 5c.

At the time of assembling, the cavities 2d and 2e of the objective lens holder are respectively inserted into an integral body of one yoke piece 5c and the permanent magnet 5a and the other yoke piece 5c, respectively. The lower end of the holding part 4 is fixed to one end of the yoke part 5.

The yoke body 5b of the yoke portion 5 includes
Positioning holes 5d and 5'd for chucking a correction mechanism described later are provided. Reference numeral 5e denotes a positioning hole for fixing the holding unit 4.

The movable section, support section 3, holding section 4 and yoke section 5 constitute an actuator section 20.

An opt base 6, which is a base of the optical head, includes a housing 6a for housing the actuator 20,
A prism 6 provided on the bottom plate 6b of the housing 6a so as to intersect the optical axis of the objective lens 1 at the bottom of the housing 6a.
c. An optical element 6d is disposed on one end surface of the opt base 6, and emits and receives laser light to and from an objective lens via a prism 6c. At the other end, an attachment portion 6e for attaching the optical head to an optical recording / reproducing device (not shown) is formed.

Next, a method of manufacturing an optical head according to an embodiment of the present invention will be described with reference to FIGS.

First, the objective lens 1 is mounted on an objective lens holder 2 to which a coil has been attached in advance and assembled as a movable part, and the support part 3 is attached to the movable part and the holding part 4. Then, the permanent magnet 5a is joined to the yoke 5 previously attached to the yoke piece 5c.

The holder 4 including the objective lens 1 is joined to the yoke portion 5 provided with the holes 5e and 5g, and the hole 5d and the tilt correction mechanism
Are inserted, and chucked on the rotation table 18b of the tilt correction mechanism 18. Rotating table 1
8b is configured to make spherical contact with the support portion 18c of the tilt correction mechanism 18, and is arranged such that the drive center of the rotary table 18b comes to the principal point position 12 of the objective lens 1.

Further, the opt base 6 is connected to the tilt correcting mechanism 18.
In, the reference position was fixed independently of the rotation position. Here, the rotation table 18b provided in the tilt correction mechanism 18 sets the opt base 6 on which the light emitting / receiving element is mounted in advance at the reference position, and sets the light emitting element at a position independent of the opt base 6 and the light emitting element. It is configured such that the determined principal point position of the objective lens 1 between the recording media 10 is set as the drive center.

After correcting the inclination of the optical head with respect to the optical axis 11, the optical head is fixed to the opt base 6 previously attached to the reference position. The operation is as follows.

First, the state of the light emitted from the light emitting element and condensed by the objective lens 1 is checked, and the inclination correction of the objective lens 1 with respect to the optical axis 11 is adjusted by turning the rotary table 18b. The yoke portion 5 is bonded to 6. The yoke portion 5 may be solder-welded to a metal yoke insert-molded on the opt base. In this way,
The optical head is completed.

Here, in the embodiment of the present invention,
Before the tilt correction, the holding section 4 including the objective lens 1 is joined to the yoke section 5 in advance. For this reason, variation in the gap distance between the permanent magnet 5a and the coils 2a and 2b is reduced.
Without being affected by the inclination correction, the assembly can be suppressed to a desired allowable error range. Further, the tilt correcting mechanism 18 is not provided on the yoke 5 or the opt base 6, but is provided on the equipment mechanism side to be manufactured. For this reason, material costs and processing costs for parts can be significantly reduced.

[0032]

As described above, in the present invention, since the optical head is not provided with a tilt correction mechanism, for example, a ball seat, the necessary space can be effectively used or omitted. In addition, since the ball seat processing is not required, the processing cost required for the processing is eliminated, so that it is not necessary to provide a mechanism for correcting inclination in the yoke portion and the opt base. This makes it possible to reduce the size, thickness, and cost of the optical head.

In the present invention, since the coil and the magnet are assembled beforehand so as to come to a fixed position before the inclination correction, the inclination correction does not affect the distance between the gaps, and the driving performance of the objective lens is not affected. The variation in the distance between the gaps can be suppressed.

Further, according to the present invention, it is possible to provide an optical pickup device using an optical head having the above advantages.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an optical head according to an embodiment of the present invention.

FIG. 2 is a partial side sectional view used for describing an inclination correction mechanism of the optical head of FIG. 1;

FIG. 3 is a cross-sectional view illustrating an example of an optical head according to the related art.

FIG. 4 is an exploded perspective view showing another example of the conventional optical head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Objective lens holder 3 Support part 4 Holder 5, 8, 13 Yoke part 6, 9, 14 Opt base 7 Holder arm 10 Recording medium 11 Optical axis 12 Objective lens principal point 15 Spring 16, 17 Screw 18 Tilt Correction mechanism

Claims (5)

[Claims] 1. An optical head for reading or writing information on a recording medium, wherein an optical axis of an objective lens focused on the recording medium is rotated in a plane including the optical axis. An actuator for driving; and a base for supporting the actuator. The actuator includes a movable part on which the objective lens and a movable coil are mounted, a support for movably supporting the movable part, and a support for the movable part. An optical head, comprising: a holding portion for holding the movable coil; and a yoke portion for applying a magnetic field to the movable coil, wherein the yoke portion is fixed to the base by bonding. 2. The optical head according to claim 1, wherein the joining of the yoke portion and the base portion is performed by welding or bonding after correcting a tilt of the objective lens with respect to an optical axis. And the optical head. 3. A method of manufacturing an optical head for reading or writing information on a recording medium, comprising: a movable section having an objective lens for focusing light on the recording medium; and the movable section movably supported. An actuator unit including a support unit and a yoke unit is integrally assembled and held, and while the base unit is supported, the actuator is relatively moved with respect to the base unit to correct the inclination of the objective lens with respect to the optical axis. A method of manufacturing the optical head, wherein the yoke portion is joined to the base portion after performing. 4. The method of manufacturing an optical head according to claim 3, wherein the base and the yoke are joined by welding or bonding. 5. An optical pickup device comprising the optical head according to claim 1.