JP2001155356A - Lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain optimization of parts without complicating the structure and the manufacture and also to sustain the assemblability, even if the parts are structured to be plurally divisible. SOLUTION: A holder 10 in which an objective lens 12 and a planar driving solenoid coil assembly 15 are provided is structured by combining a pair of divisible holder bodies 16, 17. Each divisible holder body 16, 17 is a common part of the same shape, and the holder is assembled with one holder body reversed against the other. Consequently, the complete holder 10 has omnidirectional symmetry, facilitating alignment of the center of mass, the center of inertia and the center of support.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a lens driving device for moving an objective lens applied to an optical disk driver or the like mounted on an optical information recording / reproducing device for focusing and tracking.

[0002]

2. Description of the Related Art Conventionally, an actuator such as a lens driving device used for an active control of an optical disk driver has been required to satisfy the following and high speed requirements. And B: high rigidity of the movable part for high controllability.

In order to realize this, it is necessary to reduce dead load thoroughly. The dead load mentioned here refers to gravity related to mass which does not directly contribute to thrust generation and maintenance of structural rigidity. In particular, with respect to B, since it is originally necessary to increase the natural frequency of elastic deformation, it is not only necessary to increase the rigidity. Even if A is shelved, it is necessary to reduce the equivalent mass of the distributed constant system. .

Since the natural frequency depends on the square root of the equivalent rigidity / equivalent mass ratio, the specific rigidity of the material, that is, the elastic modulus /
Materials with a high mass density ratio must be selected. However, since this is a material constant, it cannot be changed arbitrarily. Therefore, when the material is fixed, it is necessary to optimize the shape and structure in order to increase the natural frequency.

On the other hand, looking at the structure of the current practical actuator, a lens actuator having a lens offset structure as disclosed in Japanese Patent Publication No. 8-16985 is often employed due to the demand for a smaller and thinner device as a whole. Such a lens offset structure cannot satisfy Abbe's principle and alignment principle, and the rigid body natural vibration given by the rigidity of the support structure and the concentrated mass of the movable part is coupled with the active drive, thereby deteriorating controllability. Often.

When focusing attention on the structure of the movable portion in the lens driving device, a minimum holder is a single holder that integrates the objective lens, which is a so-called payload, and the driving solenoid coil into a supporting structure. . In order to cope with the above-mentioned rigid natural vibration, the holder generally performs a weight balance so as to cancel the first moment of inertia of the objective lens and bring the center of mass close to the center of thrust and the center of support.

[0007]

From the viewpoint of reviewing the aforementioned shape and structure optimization, reduction of dead load is the most critical issue. In actual parts, it is necessary to have a shape that can maintain assembly accuracy or assembly workability even if it is a dead load due to dynamics, and the parts themselves are also easy to make while maintaining accuracy and strength. Must. This is the reason why it is difficult to achieve a reduction in dead load in the structure after assembly.

[0008] In this case, it is sufficient to make the parts into a plurality of divided shapes and to minimize the volume after the assembly so as to satisfy the above-mentioned necessary functions.
If it is easily performed, the number of parts and the number of steps are increased, and positioning for connecting the two is required, which causes problems such as complicating the structure.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to optimize the parts without complicating the structure and the production thereof even if the parts are divided into a plurality of divided structures, and to reduce the assemblability. It is an object of the present invention to provide a lens driving device that does not cause the lens driving device.

[0010]

To achieve the above object, the present invention provides a holder provided with an objective lens, a support for elastically supporting the holder so as to be displaceable, and a magnetic circuit portion comprising a magnet and a yoke. And a solenoid coil installed opposite to the magnetic circuit unit for generating focusing and tracking thrusts on the holder, for focusing and tracking the objective lens during recording / reproducing on an optical information recording medium. Wherein the holder is divided into a plurality of parts to form a divided holder member, at least the objective lens is assembled at a predetermined position of the divided holder member, and the divided holder members are integrally assembled. Depending on the configuration, only the holder is divided into multiple parts, the configuration is the minimum part, and the structure It is possible to create a Masui part shape.

In the present invention, the divided holder members have the same shape. With this configuration, a plurality of divided holder members can be used as common parts, so that the structural symmetry can be easily satisfied. And is advantageous in terms of process control or cost.

In the present invention, the objective lens is installed on one of the pair of divided holder members, and the weight balance body is installed on the other. By this configuration, the weight balance can be easily adjusted and the structural symmetry can be achieved. Can be easily satisfied.

Further, according to the present invention, the plate-shaped solenoid coil is interposed between the pair of divided holder members, and the divided holder members are connected to each other, so that the solenoid coil can be easily fixed in a well-balanced manner.

Further, in the present invention, a pair of round holes are provided in each of the divided holder members, and pins are fitted into the round holes of each of the divided holder members, thereby performing positioning when the divided holder members are combined. With this configuration, it is possible to easily and accurately perform the connection.

Further, in the present invention, a split pin having a split groove formed in a side portion is used as the pin. With this configuration, it is possible to easily and easily fit the pin at the time of connection. .

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall perspective view of a lens actuator in an assembled state for explaining an embodiment of the present invention, FIG. 2 is a perspective view showing a stator portion of the lens actuator of FIG. 1, and FIG. 3 is a lens actuator of FIG. FIG. 4 is an exploded perspective view of a movable section in the actuator section of FIG.

As shown in FIGS. 1 and 2, the stator portion
The magnetic circuit unit includes magnets 2 and 3 and yokes 4 and 5, and a base 6 also serving as a back yoke of the magnetic circuit unit.

As shown in FIGS. 1, 3, and 4, the movable portion includes a holder 10 (to be described in detail later) and an objective provided in a fixing through hole 11 provided on the left side of the holder 10. Lens 1
2 and a mass balance which is a weight balance member which is disposed in a fixing through hole 13 provided at a right portion of the holder 10 and is disposed at a position where the primary moment of inertia of the holder 10 due to the provision of the objective lens 12 is canceled. 14 and a plate-shaped drive solenoid coil assembly 15, which are assembled and fixed, and integrally formed as a movable portion.

The holder 10 is basically formed by connecting a plurality of (two in this example) divided holder bodies 16 and 17, and each divided holder body 16 and 17 is a common part having the same shape. Then, one of the divided holder bodies 16 and 17 is assembled so as to be turned upside down with respect to the other, so that alignment of the center of mass, the center of inertia, and the center of support is facilitated by omnidirectional symmetry.

Usually, the assembling is often carried out with reference to the objective lens mounting hole, which requires the most accuracy in the shape of the holder, but in this embodiment, each of the divided holder bodies 16 and 17 constituting the holder 10 is assembled. Since a pair of fixing holes 11 and 13 having the same shape as an objective lens mounting hole or a mass balance mounting hole are formed symmetrically in each case, positioning can be easily performed, and positioning accuracy is improved.

In this embodiment, the mass balance 14 is made of a metal stamped part which has been frequently used, and is fixed to the inner surface of the fixing through-hole 13 of the right divided holder 17. However, an object having the same mass as the objective lens 12 may be arranged at a position completely symmetrical with the objective lens 12, and the objective lens 12
The objective lens itself or a mechanically similar objective lens which is optically defective may be diverted.

Further, the driving solenoid coil assembly 15
In this example, a laminated coil formed in a substrate shape by an etching method or the like is illustrated, but in addition to this example, a wound coil is fixed to a conventional wiring substrate and subjected to electrical conduction processing. You may.

As shown in FIGS. 1 and 3, a plurality of (four in this example) doubling as power supply lines are provided on lands formed on the drive solenoid coil assembly 15 in this example. One end of the supporting wire spring 20 is fixed by soldering. The other end of each supporting wire spring 20 is fixed block 21
Is fixed to the flexible printed circuit board 22 fixed to the side surface of. In the present embodiment, an example in which soldering is performed for power supply connection as a fixing method has been described. However, an appropriate wire spring or leaf spring may be used, and an adhesive or insert molding method may be employed as the fixing method.

As shown in FIG. 4, in assembling the movable part, when integrating these series of parts, high precision and strength are required, so that the positioning structure and shape need to be devised. In the present embodiment, the inner surfaces of the divided holder bodies 16 and 17 facing each other and the plate-shaped drive solenoid coil assembly 15
In the corresponding portions in the above, the positioning round holes 25, 2
6 and 27 are provided in pairs, and each round hole 25, 26,
27 is fitted with a pin or split pin 28, and the driving solenoid coil assembly 1 is inserted between the pair of split holder bodies 16 and 17.
5 are connected to each other. Then, it is positioned and connected as described above and firmly fixed by screwing or bonding.

FIG. 4 shows an example in which the split pin 28 is used. However, since the divided holder bodies 16 and 17 are common parts and the accuracy between the cores of the pair of round holes is good, a solid pin is used. Alternatively, only one of the round holes 26 in the drive solenoid coil assembly 15 may be elongated.

As described above, in the present embodiment, in order to satisfy a plurality of conflicting mechanical requirements, the holder 10 is divided into a pair of divided holder bodies 16 and 17 while each of the divided holder bodies 16 and 17 is divided. By using 17 as a common part, it is possible to minimize the burden on parts and man-hours, improve structural accuracy and strength in assembly, and provide an excellent movable structure due to structural symmetry.

[0028]

As described above, according to the present invention,
Divide at least the holder for fixing the objective lens,
A structure that can be integrated after assembly has a movable structure with a high rigidity / mass and thrust / mass ratio that effectively eliminates dead loads after assembly without compromising accuracy or strength during component manufacturing. A lens driving device can be provided.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an assembled lens actuator for describing an embodiment of the present invention.

FIG. 2 is a perspective view showing a stator unit in the lens actuator of FIG. 1;

FIG. 3 is a perspective view showing an actuator unit in the lens actuator of FIG. 1;

FIG. 4 is an exploded perspective view of a movable section in the actuator section of FIG. 3;

[Explanation of symbols]

 2,3 Magnet 4,5 Yoke 6 Base 10 Holder 11,13 Fixing Through Hole 12 Objective Lens 14 Mass Balance 15 Drive Solenoid Coil Assembly 16,17 Split Holder Body 20 Supporting Wire Spring 21 Fixed Block 22 Flexible Printed Board 25 , 26,27 Round hole 28 Split pin

Claims (6)

[Claims] 1. A holder provided with an objective lens, a support member for elastically supporting the holder so as to be displaceable, a magnetic circuit portion including a magnet and a yoke, and a magnetic circuit portion provided opposite to the magnetic circuit portion so as to face the holder. A lens driving device comprising: a solenoid coil for generating a focusing and tracking thrust; and a drive unit for driving the objective lens to perform focusing and tracking during recording / reproducing on an optical information recording medium. A lens driving device, wherein at least the objective lens is assembled at a predetermined position of the divided holder member, and the divided holder member is integrally assembled. 2. The lens driving device according to claim 1, wherein said divided holder members have the same shape. 3. The lens driving device according to claim 1, wherein an objective lens is provided on one of the pair of divided holder members, and a weight balance body is provided on the other. 4. The lens driving device according to claim 1, wherein the plate-shaped solenoid coil is interposed between the pair of divided holder members to connect the divided holder members. 5. The positioning when the divided holder members are combined by providing a pair of round holes in each of the divided holder members and fitting a pin into the round hole of each divided holder member. Item 5. The lens driving device according to item 1, 2, 3, or 4. 6. The lens driving device according to claim 5, wherein a split pin having a split groove formed on a side is used as the pin.