JP3471497B2 - Method of manufacturing objective lens driving 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 objective lens driving device for an optical pickup that records and reproduces information on an optically recorded disc and a method for manufacturing the same.

[0002]

2. Description of the Related Art An objective lens driving device is provided in an optical pickup of an optical information recording / reproducing device such as a magneto-optical disk device capable of recording / reproducing information or an optical disk device. An objective lens for focusing a light beam on a recording surface of an optical recording disk as a recording medium when the apparatus is in operation is provided.

Conventionally, in such an objective lens driving device, the objective lens is generally attached to an objective lens holding body for holding the objective lens with an adhesive or
It is fixed by a mounting member and a mounting screw.

However, fixing the objective lens and the objective lens holder with an adhesive causes the following problems.
That is, in order to drive the objective lens driving device, it is necessary to reduce the size and weight of the objective lens and the objective lens holder, but in order to fix the objective lens and the objective lens holder with an adhesive, Adhesive space is required, and both the objective lens and the objective lens holder become large. Also,
As the size increases, the weight becomes heavier and the weight of the adhesive is added. For this reason, it is inevitable that the portion to be driven becomes large and heavy, which adversely affects the performance of the objective lens driving device.

Further, by fixing the objective lens and the objective lens holder with an adhesive, they cannot be driven integrally at a high frequency, which also adversely affects the performance of the objective lens driving device.

Further, when fixing the objective lens to the objective lens holder, positional accuracy and inclination accuracy are required. However, in this case, in order to fix the objective lens to the objective lens holding body, generally, the objective lens is fixed by being fitted into the objective lens holding body, which causes rattling and the like. It is difficult to maintain the inclination accuracy.

Further, the effect of the adhesive causes distortion in the objective lens, which deteriorates the performance of the objective lens driving device. Further, there is a problem in that the cost of manufacturing increases due to the work such as bonding.

Further, when the objective lens is sandwiched between the mounting members and fixed to the objective lens holding body by the mounting screws, there is a problem that the number of parts is increased and the production cost is increased. Further, in this case, since the positioning of the objective lens depends on the positional accuracy of the mounting member, there is a problem that accurate positioning is difficult unless the objective lens and the mounting member are fitted properly.

In view of this, in Japanese Patent Laid-Open No. 62-51040, the objective lens and the objective lens holder are made compact and lightweight by integrally molding the objective lens and the objective lens holder by molding the same resin material. In addition, there is disclosed an objective lens driving device capable of accurately positioning the objective lens.

Further, in Japanese Patent Laid-Open No. 6-51174,
A method is disclosed in which the objective lens and the mounting member are integrally formed by insert molding or outsert molding to reduce the number of steps and the number of parts and obtain a lens with high positioning accuracy.

[0011]

However, JP-A-62-62
When the objective lens and the objective lens holder are integrally molded with the same resin material as disclosed in Japanese Patent Laid-Open No. 51040, a new problem different from the above problem occurs.

The conditions required for the material of the objective lens made of synthetic resin are (1) little variation in refractive index, (2) little birefringence, and (3) good resin fluidity during molding. And (4) high moisture absorption resistance, and (5) transparency required for optical lenses.

However, when the objective lens and the objective lens holder are integrally molded with the same resin material by using a resin material that satisfies the above-mentioned requirements for the objective lens material, the bending elasticity (hardness) of the objective lens holder is increased. Therefore, when the objective lens holder is driven in a high frequency band, resonance occurs and the performance required as the objective lens driving device cannot be maintained.

Therefore, the bending elasticity of the objective lens holder can be enhanced by impregnating the objective lens holder with glass fiber or carbon fiber, but the resin material is impregnated with glass fiber, carbon fiber or the like. Therefore, the material conditions 1 to 5 necessary for the material of the objective lens cannot be satisfied.

That is, when the objective lens and the objective lens holder are integrally molded using a material having a high bending elasticity, there is no material satisfying the material conditions required for the objective lens. For this reason, it is difficult to mold and integrate the objective lens and the objective lens holder with the same material, and it is difficult to obtain an objective lens driving device that can sufficiently exhibit the required performance.

Further, as disclosed in JP-A-6-51174, when the objective lens and the mounting member are integrally molded, the man-hours and the number of parts are reduced as compared with the case where a separate mounting member is used. Although it can be reduced,
Since the objective lens is fixed to the objective lens holder by screwing, there is a risk of backlash and the like, and it is hard to say that the positional accuracy and the inclination accuracy can be sufficiently improved. Further, since the objective lens is screwed, the weight of the mounting screw is added. For this reason, it is inevitable that the weight of the portion to be driven is increased, which may adversely affect the performance of the objective lens driving device.

The present invention has been made in view of the above problems, and an object thereof is to provide a compact and lightweight objective lens driving device which can maintain the performance required as an objective lens driving device even in a high frequency band. To do.

[0018]

According to claim 1 of the present invention.
A method of manufacturing an objective lens driving device solves the above problems.
In order to focus the light beam on the recording surface of the recording medium
Objective lens and holding means for holding the objective lens
And the objective lens and the holding means are different from each other.
Made of material and holds the outer peripheral rib of the objective lens
Objective lens drive integrally molded to enclose the means
A method of manufacturing a moving device, comprising the objective lens and holding means.
And, after molding the holding means, an acrylic resin and
Any one selected from the group consisting of polyolefin resins
By injection molding the objective lens with the material
It is characterized by being integrally molded.

The objective lens driving device according to claim 2 of the present invention.
In order to solve the above problems, the manufacturing method of
Holding means is polyphenylene sulfide, polycarbonate
, Liquid crystal polymer, polyphthalamide
Characterized by being made of any one type of material
It

According to the above structure, the objective lens and the holder are
By performing injection molding when integrally molding the step,
Easy to use objective lens and holding means made of different materials
Can be integrated. Further, according to the above configuration,
The objective lens and the holding means are molded into the holding means.
Made of acrylic resin and polyolefin resin
The objective lens is made of any one material selected from the group.
By integrally molding by injection molding
Objective lens without stress due to molding
The holding means and the holding means can be easily integrated.

According to the above arrangement, the objective lens and
The holding means and the holding material are integrally molded using different materials.
The objective lens and the holding means are respectively
Can meet the necessary conditions. Above objective lens
From the group consisting of acrylic resin and polyolefin resin
Objective lens made of any one of the materials selected
Conditions, such as variation in refractive index and small birefringence
, Good resin fluidity during molding, moisture absorption resistance and transparency
You can meet the requirements such as high.

Further , the holding means is a polyphenylene sensor.
Rufide, polycarbonate, liquid crystal polymer, polyf
Any kind of material selected from the group consisting of taramide
In Lana Rukoto, conditions necessary for the holding means, i.e., bending elasticity
It is possible to meet the requirements such as high cost.

The objective lens drive obtained by the present invention is also
In the moving device, the objective lens and the holding means are integrally molded.
This allows the objective lens to have excellent position accuracy and tilt accuracy, and
Even if the frequency is high, the objective lens and the holding means can be driven integrally.
It That is, the objective lens driving device obtained by the present invention
Is required as an objective lens driving device even in a high frequency band
It is possible to maintain excellent performance.

Further, the objective lens obtained by the present invention
For the drive unit, use adhesives or mounting tools such as mounting screws.
Since it is not used, it may be affected by the adhesive,
Space is not required, so it is smaller and lighter.
be able to.

The objective lens driving device according to claim 3 of the present invention.
In order to solve the above problems, the manufacturing method of
Glass fiber or carbon fiber is mixed with the material of the holding means.
It is characterized by doing. According to the above configuration,
The bending elasticity of the holding means can be further enhanced.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] The following will describe one embodiment of the present invention with reference to FIGS. 1 to 5. As shown in FIG. 4, the objective lens driving device 28 according to the present embodiment is an optical pickup 2 of an optical information recording / reproducing device such as a magneto-optical disk device capable of recording / reproducing information or an optical disk device.
It is equipped with 3.

The optical pickup 23 has a recording surface 21a of an optical recording disk (hereinafter simply referred to as a disk) 21 as a recording medium which is rotationally driven by a motor 22 during operation of the optical information recording / reproducing apparatus. And the reflected light from the disc 21 is taken in and the feed mechanism 29 provided with a driving means such as a linear motor in the direction parallel to the recording surface 21a of the disc 21, that is, the tracking direction. It is supposed to be moved.

The optical pickup 23 is a laser light source 24.
And the deflection mirror 25 and the objective lens 2. The laser light source 24 and the deflection mirror 25 are arranged in the pickup housing 27, while the objective lens 2 is provided.
Is located above the deflection mirror 25, and the objective lens driving device 28
It is located inside.

As shown in FIG. 2, the objective lens driving device 28 comprises an objective lens 2, an objective lens holder (holding means) 1, a focusing coil 3, a tracking coil 4 and a substrate 5. Holder assembly 2
0 is the outer base 6 which is the base of the objective lens driving device 28.
Leaf spring 1 extending from a plate-shaped fixed substrate 16 fixed to the
It has a structure in which it is swingably supported by 3.

On the outer base 6, flat plate-shaped outer yokes 7, 7 are provided at symmetrical positions with respect to a through hole (not shown) formed at the central position of the outer base 6, respectively. Flat magnets 8 for driving the objective lens holder assembly 20 are fixed to the opposing surfaces of the outer yokes 7, 7.

A flat plate-shaped inner base 9 smaller than the outer base 6 is formed on the outer base 6 so that a through hole (not shown) formed in the inner base 9 overlaps with a through hole formed in the outer base 6. It is fixed by a screw 10. On the inner base 9, a flat plate-shaped inner yoke 11
11 are provided at positions symmetrical with respect to the objective lens holder assembly 20 so as to face the outer yokes 7.

Further, a ceiling yoke 12 is mounted between the outer yoke 7 and the inner yoke 11 which face each other. As a result, a magnetic circuit is formed by the outer yoke 7, the magnet 8, the inner yoke 11, and the top yoke 12.

The fixed board 16 is provided on the outer base 6.
However, the outer yokes 7 and 7 are erected at a lateral position in a direction in which the outer yokes 7 and 7 oppose each other via a spacer 14 and fixed by screws 15.

An objective lens holder 1 for holding the objective lens 2 is arranged above the through holes provided in the outer base 6 and the inner base 9. As shown in FIG. 1, the objective lens holder 1 is provided with a through hole 1a penetrating in the vertical direction at its center position, and as shown in FIGS. 2 and 3, inner yokes 11 and 11 are formed.
Notches 1b for inserting the inner yokes 11 and 11 are formed on the respective side surfaces facing each other.

Then, as shown in FIG. 3, an objective lens 2 is attached to the center of the objective lens holder 1.
Further, a focusing coil 3 is wound around the outer peripheral side surface of the objective lens holder 1, and a pair of pairs is provided on each surface of the portion of the focusing coil 3 that covers the cutouts 1b and 1b from the side. Tracking coil 4
... is stuck.

On the other hand, the cutout portion 1 of the objective lens holder 1
By holding substrates 5 and 5 used for lead wire processing of the focusing coil 3 and the tracking coil 4 on the surface of the focusing coil 3 on the side surface where b. A body assembly 20 is formed. It should be noted that this objective lens holder assembly 20 is a part of the objective lens driving device 28 that is actually driven.

As a result, the action of the magnetic field generated in the magnetic circuit and the flow of electric current through the focusing coil 3 and the tracking coil 4 cause the objective lens holder assembly 20 to move in the optical axis direction of the objective lens 2, that is, , The focus direction perpendicular to the recording surface 21a of the disk 21, or the optical axis direction of the objective lens 2 and the disk 21.
Is driven in a direction orthogonal to the rotation direction, that is, in a tracking direction parallel to the recording surface 21a of the disk 21.

At this time, the objective lens holder assembly 20 is
As shown in FIG. 2, it is supported by a pair of leaf springs 13 provided on both sides of the inner yoke 11 and the outer yoke 7 located on the fixed substrate 16 side. That is,
One end of the leaf spring 13 is on the substrate 5, and the leaf spring 13 is
The other end of is fixed to the fixed substrate 16 by soldering. As a result, the objective lens holder assembly 20 is held substantially horizontally by being separated upward from the inner base 9 and the outer base 6 by the four leaf springs 13 and is held inside the notches 1b and 1b. The yoke 11 is held in a state of being inserted therethrough, and in this state, the center-side portions of the tracking coils 4 and the focusing coil 3 which are adjacent to each other are located between the magnet 8 and the inner yoke 11. Each is located in the magnetic circuit of.

The leaf spring 13 is made of beryllium copper or dron bronze, and the focusing coil 3 is used.
It also serves as a current supply to the tracking coil 4.

In the optical information recording / reproducing apparatus having such an objective lens driving device 28, as shown in FIG. 4, when laser light is emitted from the laser light source 24 arranged in the pickup housing 27, This laser light
After being deflected by the deflecting mirror 25, after passing through the through holes of the outer base 6 and the inner base 9 of the objective lens driving device 28 and the through hole 1a of the objective lens holder 1, the objective lens 2 causes the recording surface 21a of the disk 21 to reach the recording surface 21a. Collected. Then, the information recorded on the recording surface 21a is read by the reflected light according to the direction of magnetization on the recording surface 21a.

When the disk 21 is irradiated with the laser light as described above, first, the recording surface 21a of the disk 21 is moved by the optical pickup 23 by the feeding operation of the feeding mechanism 29.
Moves in parallel with, and high-speed access is performed to the target track. Then, following the access of the optical pickup 23, a drive signal to the objective lens drive device 28 is generated based on the detected change amount of the reflected light from the recording surface 21a. That is, the focus position of the laser light is the recording surface 21a.
Focusing coil 3
To the focusing coil 3.
The outer yoke 7, the magnet 8, the inner yoke 11,
The electromagnetic force in the focus direction acts on the portion located inside the magnetic circuit formed by the top yoke 12. This electromagnetic force causes the objective lens holder 1 to move the leaf springs 13
The curved deformation of 13 is generated in the vertical direction and the lens is driven in the vertical direction, whereby the focal position of the objective lens 2 is corrected so as to match the recording surface 21a of the disk 21.

Similarly, by energizing the tracking coils 4 ... And applying an electromagnetic force to these tracking coils 4, the objective lens holder 1 is moved to each leaf spring 1.
It is driven by causing a curved deformation in the tracking direction in 3 · 13. As a result, the focal position of the objective lens 2 is corrected so as to match the predetermined tracking on the recording surface 21a of the disc 21.

The driving of the objective lens driving device 28 as described above needs to follow the disc 21 rotating at high speed at high speed in order to stabilize the recording / reproducing state on the disc 21. Objective lens driving device 28
Is required to maintain its performance even in a high frequency band and to be further reduced in size and weight.

Generally, the conditions necessary for the material of the objective lens are (1) there is little variation in the refractive index,
(2) Low birefringence, (3) Good resin fluidity at the time of molding, (4) High moisture absorption resistance, (5) Required transparency of optical lens, and the like. Also,
Bending elasticity (hardness) and the like can be mentioned as conditions necessary for the material of the objective lens holder.

Therefore, the objective lens 2 and the objective lens holder 1 are integrally molded by injection molding using different materials, so that the objective lens 2 and the objective lens holder 1 are integrally molded.
And can be easily integrated with a material satisfying the conditions required for the objective lens and the objective lens holder described above. Further, by integrally molding the objective lens 2 and the objective lens holder 1 by injection molding, it becomes possible to easily obtain the tilt and position accuracy of the objective lens 2.
Even at a high frequency, the objective lens 2 and the objective lens holder 1 are integrally driven.

When the above method is used, it is not necessary to bond with an adhesive as in the conventional case, and a mounting tool such as a mounting screw for mounting the objective lens is not required.
For this reason, the objective lens 2 is not affected by the adhesive agent, does not require a space for adhesion, and can be reduced in size and weight, and the work is also simplified.

[0047] As a material of the objective lens 2, if materials satisfying required for the objective lens (1) to (5), is not particularly limited, an acrylic resin, a polyolefin resin is preferred .

As the material of the objective lens holder 1,
The material is not particularly limited as long as it is a material satisfying the necessary condition for the objective lens holder, but P having relatively high bending elasticity is used.
PS (polyphenylene sulfide), PC (polycarbonate), LCP (liquid crystal polymer) and PPA (polyphthalamide) are preferable. Further, glass fibers, carbon fibers or the like may be added to the above materials in order to further increase the bending elasticity.

When integrally molding the objective lens 2 and the objective lens holder 1, as shown in FIG. 1, the objective lens holder 1 is injection-molded so as to wrap the outer peripheral rib 2a of the objective lens 2. Thus, the objective lens 2 and the objective lens holder 1 can be integrated.

In this case , the objective lens 2 is an acrylic resin,
If made of a synthetic resin such as polyolefin resin, among injection molding is also heat-resistant temperature of the material also is necessary to consider, but after molding the objective lens holder 1, an objective lens 2
By molding, that is, by outsert molding,
The objective lens 2 and the objective lens holder 1 can be easily integrated without giving stress to the objective lens 2 due to molding.

As described above, in the objective lens driving device 28 according to the present invention, the objective lens 2 and the objective lens holder 1 are integrally molded by using different materials, so that the objective lens 2 and The objective lens holder 1 can satisfy the necessary conditions for each.

[0052] Therefore, the objective lens is an acrylic resin, that consist of one kind of material selected from the group consisting of polyolefin resin, the conditions required for the objective lens,
For example, it is possible to satisfy the conditions that there are few variations in the refractive index and birefringence, the resin fluidity at the time of molding is good, and the moisture absorption resistance and transparency are high.

The objective lens holder 1 is made of PP
By being made of any one kind of material selected from the group consisting of S, PC, LCP and PPA, the condition required for the holding means,
That is, it is possible to satisfy the conditions such as high bending elasticity.

Further, in the objective lens driving device 28 according to the present invention, since the objective lens 2 and the objective lens holding body 1 are integrally molded, the objective lens 2 is excellent in the positional accuracy and the inclination accuracy, and even at a high frequency. The objective lens 2 and the objective lens holder 1 are integrally driven. That is, the objective lens driving device 28 according to the present invention can maintain the performance required as the objective lens driving device even in a high frequency band.

Further, since the objective lens driving device 28 according to the present invention does not use an adhesive agent or an attaching tool such as an attaching screw, it is not affected by the adhesive agent and does not require a space for adhesion. It can be made smaller and lighter.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, the shape of the objective lens 2 may be spherical or aspherical, and its outer shape is not particularly limited as long as it can exhibit the performance required for the objective lens. Furthermore, the width (length) of the outer peripheral rib 2a also <br/> is not particularly limited.

[0057]

The objective lens drive according to claim 1 of the present invention
As described above, the device manufacturing method is performed on the recording surface of the recording medium.
The objective lens for focusing the light beam and the objective lens
Holding means for holding and holding the objective lens.
The holding means is made of different materials, and the objective
Molded integrally so that the holding means wraps the outer peripheral rib of the lens
A method for manufacturing an objective lens driving device, comprising:
The objective lens and the holding means are molded into the holding means.
After that, a group consisting of acrylic resin and polyolefin resin
The objective lens is made of any one material selected from
Is integrally molded by injection molding.

The objective lens driving device according to claim 2 of the present invention.
As described above, the method for manufacturing
Enylene sulfide, polycarbonate, liquid crystal polymer
-, Any one selected from the group consisting of polyphthalamide
It is composed of seed materials.

According to the above arrangement, the objective lens and the holder are
By performing injection molding when integrally molding the step,
Easy to use objective lens and holding means made of different materials
The effect that it can be integrated is produced. Also on
According to the above configuration, the objective lens and the holding means are
After molding the holding means, the acrylic resin and the polyole
For any kind of material selected from the group consisting of fin resin
Therefore, the objective lens can be integrated by injection molding.
By shaping, the stress due to molding is applied to the objective lens.
The objective lens and the holding means can be easily integrated without giving them.
The effect that can be achieved.

According to the above construction, the objective lens and
The holding means and the holding material are integrally molded using different materials.
The objective lens and the holding means are respectively
Can meet the necessary conditions. Above objective lens
From the group consisting of acrylic resin and polyolefin resin
Objective lens made of any one of the materials selected
Conditions, such as variation in refractive index and small birefringence
, Good resin fluidity during molding, moisture absorption resistance and transparency
You can meet the requirements such as high.

Further , the holding means is a polyphenylene sensor.
Rufide, polycarbonate, liquid crystal polymer, polyf
Any kind of material selected from the group consisting of taramide
Therefore, the condition required for the holding means, that is, bending elasticity
Has the effect of being able to satisfy conditions such as high
It

The objective lens drive obtained by the present invention is also
In the moving device, the objective lens and the holding means are integrally molded.
This allows the objective lens to have excellent position accuracy and tilt accuracy, and
Even if the frequency is high, the objective lens and the holding means can be driven integrally.
It That is, the objective lens driving device obtained by the present invention
Is required as an objective lens driving device even in a high frequency band
It is possible to maintain excellent performance.

Further, the objective lens obtained by the present invention
For the drive unit, use adhesives or mounting tools such as mounting screws.
Since it is not used, it may be affected by the adhesive,
Space is not required, so it is smaller and lighter.
be able to.

The objective lens driving device according to claim 3 of the present invention.
As described above, the manufacturing method of the device is as follows.
A glass fiber or carbon fiber
It According to the above structure, the bending elasticity of the holding means is improved.
The effect is that it can be further increased.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an objective lens driving device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an overall configuration of the objective lens driving device.

FIG. 3 is a perspective view showing a configuration of an objective lens holder assembly in the objective lens driving device.

FIG. 4 is a schematic diagram showing an overall configuration of an optical information recording / reproducing device incorporating the objective lens driving device .

[Explanation of symbols]

1 Objective lens holder 2 Objective lens

Claims (3)

(57) [Claims] 1. A light beam is focused on a recording surface of a recording medium.
Objective lens and a holding hand for holding the objective lens
The objective lens and the holding means are different from each other.
The outer ribs of the objective lens are preserved.
Objective lens integrally molded so as to wrap around the holding means
A method of manufacturing a drive device, comprising molding the objective lens and the holding means by molding the holding means.
Made of acrylic resin and polyolefin resin
The objective lens is made of any one material selected from the group.
It is characterized by being integrally molded by injection molding
Method for manufacturing an objective lens driving device. 2. The holding means is polyphenylene sulfide.
, Polycarbonate, liquid crystal polymer, polyphthalamide
It consists of one kind of material selected from the group consisting of
An objective lens driving device according to claim 1,
Build method. 3. The material of the holding means is glass fiber or
Carbon fiber is compounded, Claim 1 characterized by the above-mentioned.
Is a method for manufacturing an objective lens driving device according to 2.