JP2006260695A - Objective lens driving system, optical pickup system, and optical disk driving system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective lens driving system which keeps the normal positions of movable parts in assembling by assembling the movable parts without warpage of elastic boards due to heating in soldering the elastic board and elastic support members if holding each one end of the elastic support members when supporting the movable parts with the other ends of the elastic support members whose one end is fixed. <P>SOLUTION: The objective lens driving system is provided with a plurality of the elastic support members 30 whose each one end is fixed to an objective lens holder 4, fixing parts 21 for supporting the other ends of the elastic support members, a driving means for driving the objective lens holder, and the elastic board 22 which have fixed parts 22a fixed to a fixing member in the vicinity of a center in a tracking direction within a surface including a focus direction and the tracking direction, where both of the ends of the fixed parts in the tracking direction are elastically deforming parts 22b displaceable in a tangential direction and where each one end part of the elastic support members is connected to the elastic deforming parts. In the elastic board, each constitution of material, thickness and shapes are symmetrical with respect to the center of a thickness direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an objective lens driving device used in an optical disc apparatus that records and / or reproduces information on the optical disc by projecting laser light onto the optical disc, an optical pickup device including the objective lens driving device, and an optical pickup device. The present invention relates to an optical disc drive apparatus provided.

An optical disc drive apparatus that records and reproduces information by projecting laser light emitted from a laser light source onto a disc-shaped recording medium such as a CD or a DVD includes a pickup module. A spindle motor for rotating the optical disk and a seek rail are fixed to the pickup module, and an optical pickup device is mounted on the seek rail so as to be movable in the radial direction of the optical disk on the seek rail. The optical pickup device is a device for irradiating a recording surface of an optical disc with laser light to form a light spot and receiving reflected light from the recording surface. This optical pickup device is usually provided with an objective lens driving device, and guides the light beam emitted from the light source in the optical pickup device to the recording surface of the optical disc using the objective lens in the objective lens driving device. An optical system for guiding the return light beam reflected by the light beam to a predetermined light receiving position, a light receiving element disposed at the light receiving position, and the like. The objective lens driving device drives the objective lens in the focusing direction and the tracking direction so that the light beam spot is accurately irradiated to a predetermined position on the disk by using a control signal obtained from the reflected light.
There are several methods for movably supporting the movable part (movable member including the objective lens) of the objective lens driving device by the fixed part, and one of the methods mainly used at present is movable by the elastic support member. There is a method to support the part. Among these methods, as a method for supporting the elastic support member on the fixed portion side, there is one in which the elastic support member is held via an elastic substrate between the elastic support member and the fixed portion (Japanese Patent No. 3497333).
As described above, by using an elastic substrate that can be elastically deformed in the tangential direction between the fixed member and the elastic support member, the movable portion can be secured in the focusing direction and the tangential tilt direction.

However, as in the invention disclosed in Japanese Patent No. 3497333, when the structure in the thickness direction of the elastic substrate is asymmetric and the movable part is supported from one side in the tangential direction, the elastic substrate, the elastic support member, The following problems occur regarding solder assembly. That is, since the linear expansion coefficient of the elastic substrate is asymmetric with respect to the center in the thickness direction, it is deformed in the tangential direction by heating during the soldering operation, and in this state, the elastic substrate and the elastic support member are Bonded and fixed. After that, the heat of the elastic substrate dissipates, and the tangential deflection tends to return to the state before the heating, but since the solder portion is already solidified, the elastic support member fixed to the elastic substrate and the tip thereof The fixed movable part is shifted in the tangential direction, and a positional shift occurs. Also, if the movable part is supported from both sides in the tangential direction, if the bending direction of the elastic substrate is bent outward, which is the opposite direction to the movable part, the elastic substrate after soldering as in the case of one-side support The deflection in the tangential direction tends to return to the state before heating, but because there is no escape place for the elastic support member in the tangential direction because of the support on both sides, a displacement occurs that the movable part falls in the focusing direction. .
Japanese Patent No. 3497333

The present invention has been devised to solve such drawbacks of the prior art, and its purpose is to support the movable part by the other end of the elastic support member having one end fixed to the fixed part. In the structure in which one end of the elastic support member is held on the elastic substrate, the elastic substrate and the elastic support member can be assembled without causing the warp of the elastic substrate due to heating when soldering the elastic substrate and the elastic support member. It is an object of the present invention to provide an objective lens driving device capable of maintaining the normality of the lens.
That is, the invention of claim 1 makes the linear expansion coefficient symmetrical with respect to the center of the elastic substrate in the thickness direction so that the amount of expansion in the surface direction during thermal expansion is symmetric, and the elastic substrate is bent in the direction perpendicular to the surface. The purpose is to prevent.
According to the second aspect of the present invention, the difference in relative expansion and contraction in the surface direction between the wiring portion and the resin portion of the elastic substrate due to thermal expansion is reduced, and the elastic substrate in the direction perpendicular to the surface due to the relative thickness error of the double-side resin portion The purpose is to prevent the occurrence of deflection.
A third object of the present invention is to realize an elastic substrate having a necessary bending elastic force without using a dedicated substrate, and to reduce the cost.
It is an object of the present invention to reduce the difference in the amount of relative expansion and contraction in the surface direction due to thermal expansion and prevent the elastic substrate from being bent in the direction perpendicular to the surface due to a relative thickness error.
An object of the present invention is to cancel the displacement in the focus direction due to the weight of the movable part in the neutral state by using the restoring force of the elastic deformation caused by the external force of the elastic substrate.
An object of the present invention is to keep the elastic substrate flat without being bent in the tangential direction when the elastic support member and the elastic substrate are assembled.
An object of the invention of claim 7 is to cancel the displacement in the focus direction due to the moving part's own weight in the neutral state by utilizing the restoring force of the elastic deformation caused by the heating of the elastic substrate.
An object of the present invention is to provide an optical pickup device that can obtain a good signal.
An object of the invention of claim 9 is to provide an optical disk drive device capable of reading and writing data satisfactorily.

In order to achieve the above object, an invention according to claim 1 includes an objective lens for condensing light on a recording / reproducing surface of an optical disc, an objective lens holder for holding the objective lens, and one end fixed to the objective lens holder. A plurality of elastic support members for operatively supporting the objective lens holder; a fixing member for supporting other parts of the elastic support member; and a drive means for driving the objective lens holder to correct the objective lens. An elastic deformation that exists in a plane including the focusing direction and the tracking direction, has a fixed portion fixed to the fixing member near the center of the tracking direction, and both the tracking direction of the fixed portion can be displaced in the tangential direction And an elastic substrate to which one end portions of the plurality of elastic support members extending in the tangential direction with respect to the elastic deformation portion are coupled. In the objective lens driving device wherein the elastic substrate, relative to the center in the thickness direction, the material, thickness, each component shape, characterized in that symmetrical.
According to a second aspect of the present invention, in the first aspect, the elastic substrate has a wiring portion made of a conductive material at the center in the thickness direction, and the resin portion having the same material, thickness and shape on both sides in the thickness direction of the wiring portion. And a material having a difference between the linear expansion coefficient value of the wiring portion and the linear expansion coefficient value of the resin portion of 1 × 10 ⁻⁵ [cm / cm / ° C.] or less is selected in combination. And
According to a third aspect of the present invention, in the first or second aspect, the elastic substrate has reinforcing plates having the same material, the same thickness, and the same shape on both side surfaces in the thickness direction of the elastic substrate. It is characterized by.
According to a fourth aspect of the present invention, in the third aspect, the reinforcing plate is made of the same material as the resin portion of the elastic substrate.

An assembling method according to a fifth aspect of the invention includes an objective lens for condensing light on a recording / reproducing surface of an optical disc, an objective lens holder for holding the objective lens, and one end fixed to the objective lens holder. A plurality of elastic support members that operably support the lens holder; a fixing member that supports other parts of the elastic support member; drive means for driving the objective lens holder to correct the objective lens; and focusing An elastically deformable portion that exists in a plane including the direction and the tracking direction, has a fixed portion fixed to the fixing member near the center of the tracking direction, and can be displaced in the tangential direction on both sides of the fixed portion in the tracking direction. And an elastic substrate to which one ends of the plurality of elastic support members extending in a tangential direction with respect to the elastic deformation portion are coupled. In the objective lens driving device, characterized in that to fix the said elastic substrate and the elastic supporting member in said elastic substrate is elastically deformed to the objective lens holder side in the tangential direction by an external force state.
An assembling method according to a sixth aspect of the invention includes an objective lens for condensing light on a recording / reproducing surface of an optical disc, an objective lens holder for holding the objective lens, and one end fixed to the objective lens holder. A plurality of elastic support members that operably support the lens holder; a fixing member that supports other parts of the elastic support member; drive means for driving the objective lens holder to correct the objective lens; and focusing An elastically deformable portion that exists in a plane including the direction and the tracking direction, has a fixed portion fixed to the fixing member near the center of the tracking direction, and can be displaced in the tangential direction on both sides of the fixed portion in the tracking direction. And an elastic substrate to which one ends of the plurality of elastic support members extending in a tangential direction with respect to the elastic deformation portion are coupled. In the objective lens driving device, wherein the elastic substrate is fixed to said elastic substrate and the elastic supporting member in the regulated state so as not bent in the tangential direction.

An objective lens driving device according to a seventh aspect of the present invention is an objective lens for condensing light on a recording / reproducing surface of an optical disc, an objective lens holder for holding the objective lens, and one end fixed to the objective lens holder. A plurality of elastic support members that operably support the objective lens holder; a fixing member that supports other parts of the elastic support member; and a drive unit that drives the objective lens holder to correct the objective lens; An elastically deformable portion that exists in a plane including the focusing direction and the tracking direction, has a fixed portion fixed to the fixing member near the center of the tracking direction, and is capable of displacing both sides of the fixed portion in the tangential direction. And an elastic substrate to which one end portions of the plurality of elastic support members extending in a tangential direction with respect to the elastic deformation portion are coupled. The elastic substrate has an asymmetrical structure of material, thickness, and shape with respect to the center in the thickness direction, and is reversibly deformed toward the objective lens holder in the tangential direction by heating. It is characterized by having.
An optical pickup device according to an eighth aspect of the present invention is assembled by a light source that emits a light beam, the objective lens driving device according to any one of the first to fourth or seventh aspects, or the assembling method according to the fifth or sixth aspect. An objective lens driving device, and an optical system that enters the light flux into the objective lens in the objective lens driving device, guides return light reflected by the recording / reproducing surface and passing through the objective lens to a predetermined light receiving position. And a photodetector arranged at the light receiving position.
An optical disk drive apparatus according to an invention of claim 9 is an optical pickup apparatus according to claim 8, a seek mechanism for moving the optical pickup apparatus in a radial direction of the optical disk, a spindle motor for rotating the optical disk, and the optical And a processing device for performing at least reproduction among recording, reproduction and erasure of the information using an output signal of the pickup device.

According to the first aspect of the present invention, since the linear expansion coefficient is symmetric with respect to the thickness direction center of the elastic substrate, the amount of expansion in the surface direction at the time of thermal expansion is also symmetric. It is possible to prevent the occurrence of deflection.
According to the invention of claim 2, the difference in relative expansion / contraction amount between the wiring pattern portion of the elastic substrate and the resin film portion due to thermal expansion is reduced, and the surface vertical direction due to the relative thickness error of the double-sided resin film portion. It is possible to prevent the elastic substrate from being bent.
According to the invention of claim 3, an elastic substrate having a necessary bending elastic force can be realized without using a dedicated substrate, and the cost can be reduced.
According to the invention of claim 4, it is possible to reduce the difference in the relative expansion and contraction amount in the surface direction due to thermal expansion, and to prevent the elastic substrate from being bent in the surface vertical direction due to the relative thickness error.
According to the fifth aspect of the present invention, the displacement in the focus direction due to the movable part's own weight in the neutral state can be canceled using the restoring force of the elastic deformation caused by the external force of the elastic substrate.
According to the invention of claim 6, the elastic substrate can be kept flat without being bent in the tangential direction when the elastic support member and the elastic substrate are assembled.
According to the seventh aspect of the present invention, the displacement in the focus direction due to the weight of the movable part in the neutral state can be canceled using the restoring force of the elastic deformation caused by the heating of the elastic substrate.
According to invention of Claim 8, the optical pick-up apparatus from which a favorable signal is obtained can be provided.
According to the ninth aspect of the present invention, it is possible to provide an optical disk drive device capable of satisfactorily reading and writing data.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
FIGS. 1A to 1D and 2 are explanatory views of the objective lens driving device according to the first embodiment of the present invention. FIG. 1A is a plan view of the objective lens driving device. FIG. 1B is a side view of the objective lens driving device viewed from the tracking direction, FIG. 1C is a view of the elastic substrate viewed from the tangential direction, and FIG. Expansion).
The objective lens driving device 1 is movable by connecting the movable part 2, the fixed part 20 arranged with a predetermined gap on both sides of the movable part 2 in the tangential direction, and the fixed part 20 and the movable part 2. It consists of eight elastic support members 30 in total, four each on the left and right four sides made of an elastic and conductive material such as a metal that floats and holds the portion 2 in a movable state.
The movable unit 2 includes an objective lens 3 that faces a recording surface of an optical disk (not shown), an objective lens holder 4 that holds the objective lens 3 on the upper surface in the focusing direction, and a drive that is held on both side surfaces in the tangential direction of the objective lens holder 4. It consists of a coil 5 and the like. Moreover, the movable part 2 fixes one end of each elastic support member 30 to the projecting member 2a projecting from both sides in the tracking direction, and each of the four elastic support members 30 extends symmetrically in both tangential directions. The other end is fixed to the part 20 side.

The fixing portion 20 includes a pair of left and right fixing members 21 and an elastic substrate 22 having an intermediate portion (fixed portion) 22 a fixed to the outer surface of each fixing member 21. The end portion is fixed to each elastic substrate 22. The elastic substrate 22 is in a free state at both ends in the tracking direction (elastic deformation part 22b) that are not fixed by the fixing member 21, and the other end part of each elastic support member 30 is connected to the elastic deformation part 22b in the free state. Each is fixed. The elastic substrate 22 is T-shaped as shown in FIG. 1C, and the end portion on the lower side in the focusing direction is a terminal portion 22c as a conductor exposed portion. Further, the other end portion of each elastic support member 30 is fixed to a land portion (conductor exposed portion) 22b ′ as a conductor exposed portion provided on the elastic deformation portion 22b of the elastic substrate 22 by solder or the like. That is, the elastic deformation portion 22b is provided with a land portion 22b ', and a hole into which the other end portion of the elastic support member can be inserted is provided at the center of the land portion. It is inserted into a hole and electrically connected by solder. With such a configuration, a current can be supplied from the terminal portion 22 c of the elastic substrate 22 to the drive coil 5 fixed to the movable portion 2.
A part of the elastic support member 30 is inserted through a through hole provided in the fixing member 21 and passes therethrough. As a result, the movable portion 2 is electrically connected to the elastic substrate 22 via the plurality of conductive elastic support members 30 and mechanically supported via the fixed member 21 to be operable. ing.
Each elastic support member 30 is disposed on both sides of the movable portion 2 with the axis extending in the tangential direction, and one end portion of each elastic support member 30 is connected to the movable portion 2 as described above. 5 is electrically connected to the end point. The other end of each elastic support member 30 is connected to each elastic deformation portion 22b of each elastic substrate 22 and is electrically connected to a land portion 22b ′ of the elastic substrate. The elastic substrate 22 exists in a plane including the focusing direction and the tracking direction on both sides of the tangential direction across the movable portion 2, and has an intermediate portion 22a fixed to a fixing member near the center of the tracking direction. An elastic deformation portion 22b that can be displaced in the tangential direction is provided on both sides of the tracking direction, and the other end portion of the elastic support member 30 is electrically and mechanically connected to the elastic deformation portion 22b.

As shown in FIG. 1 (d), the elastic substrate 22 has a configuration in which a wiring pattern portion (wiring portion) 22B, which is a conductive portion, is sandwiched between insulating resin films 22A, and an external portion is provided below the intermediate portion 22a. The terminal part 22c which is an entrance / exit of an electric current is provided. The resin film portion (resin portion) 22A is removed only in portions corresponding to the land portion 22b ′ and the terminal portion 22c, and the wiring pattern 22B (conductive portion) is exposed.
That is, resin film portions 22A having the same material, outer shape, and thickness are attached to both sides in the thickness direction of the wiring pattern portion 22B of the elastic substrate 22, and the terminal portions 22c and land portions as wiring portions are attached. At the same time that the entire surface of the conductive portion 22B excluding 22b ′ is covered, this outer shape forms the outer shape of the elastic substrate.
A driving magnet 25 is disposed on the inner surface of each fixed member 21 so as to face each driving coil 5 on the movable portion 2 side, and a back yoke and an objective lens are provided outside each driving magnet 25. There is a substantially U-shaped yoke base 26 that also serves as a base portion of the drive device, and the yoke base 26 fixes each fixing member 21 by rising portions at both ends. Then, the current flowing through the drive coil 5 and the magnetic flux generated by the drive magnet 25 arranged opposite to the drive coil are combined to generate a Lorentz force in the drive coil 5 so that the movable part 2 can be moved in any direction. It is possible to drive to.
The drive coil 5, the drive magnet 25, and the yoke 26 constitute drive means for driving the objective lens holder 4 to correct the objective lens 3 (the same applies to other embodiments below).

Here, the assembly of the elastic support member 30 and the elastic substrate 22 in the objective lens driving device 1 is performed as follows. That is, the movable portion 2 held by an unillustrated objective lens driving device assembly jig, the elastic support member 30, and the elastic substrate 2 in which the fixed portion (intermediate portion 22a) is fixed in advance to the fixed member 21 are respectively in predetermined positions. Is positioned. The movable portion 2 and one end of each elastic support member 30 are fixed first, and then the other end of each elastic support member 30 and the elastic substrate 22 are fixed. The other end portion of the elastic support member 30 on the elastic substrate 22 side is inserted into each of a plurality of holes at the center of the land portion 22b ′ in the elastic deformation portion 22b of the elastic substrate, and this land portion is soldered. By doing so, the elastic support member and the elastic substrate are fixed. At this time, the elastic substrate 22 receives heat, but the elastic substrate 22 is symmetrical in material, thickness, and shape with the wiring pattern portion 22B in the thickness center portion being the center in the thickness direction (tangential direction). Since the configuration is such that the linear expansion coefficient is symmetric with respect to the center in the thickness direction, and the amount of expansion in the surface direction at the time of thermal expansion is also symmetric, in the direction perpendicular to the surface of the elastic deformation portion 22b of the elastic substrate 22. It can be assembled without causing any deflection. As a result, in the assembly of the objective lens driving device, the position accuracy of the movable portion 2 in the neutral state (no load state) can be improved, the DC offset current can be reduced, and the DC current distribution and AC current distribution of the other axis can be achieved. Can be increased. Similarly, even during use, the elastically deforming portion of the elastic substrate 22 does not bend due to a change in ambient temperature, and thus it is possible to realize an objective lens driving device that is stable with respect to a change in ambient temperature.
In the above description, the moving coil type objective lens driving device in which the driving coil 5 is mounted on the movable portion 2 is used. However, the moving magnet type objective lens driving device has the same effect.

Next, FIGS. 2A and 2B are cross-sectional views in the thickness direction of the elastic substrate 22, and the thickness of each resin film portion (resin portion) 22A on both sides of the wiring pattern portion (wiring portion) 22B is as follows. In the example of FIG. 2A, there is a relationship of “one resin film thickness t1a> the other resin film thickness t1′a”. In the example of FIG. The thickness of the resin film t1b> the thickness of the other resin film t1′b ”.
FIG. 2A shows the case where the linear expansion coefficient of the material of the wiring pattern portion 22B is different from the linear expansion coefficient of the material of the resin film 22A on both sides in the thickness direction (resin film portion linear expansion coefficient> wiring pattern portion linear expansion coefficient). FIG. 2B shows a case where the linear expansion coefficient of the wiring pattern member material and the linear expansion coefficient of the resin film member material on both sides in the wiring pattern portion thickness direction are substantially equal (the difference between the linear expansion coefficients is about 1 × 10 ⁻⁵ [cm / cm / ° C.] or less). Each figure shows the amount of extension L1a, L1′a, L2a, L1b, L1′b, L2b of the wiring pattern portion 22B and the resin film portion 22A when the elastic substrate 22 is heated, and the wiring pattern portion 22B and the resin film portion. This represents the forces Fa, F′a, Fb, and F′b that the wiring pattern portion receives from the resin film portion at the boundary surface between the wiring pattern portion and the resin film portion due to the difference in elongation from 22A.
In FIG. 2A, since the linear expansion coefficient of the resin film portion 22A is larger than that of the wiring pattern portion 22B, L1a = L1′a> L2a, and two boundary surfaces between the resin film portion 22A and the wiring pattern portion 22B. Then, the wiring pattern portion receives forces Fa and F′a from the respective resin film portions (Fa> F′a). The forces Fa and F′a cause the bending direction forces Fr and F′r to act on the wiring pattern portion, and the forces are not equal due to the difference in thickness between the left and right resin film portions (Fr> F′r). Therefore, the elastic substrate is bent in the direction perpendicular to the surface without being canceled. On the other hand, in FIG. 2B, since the linear expansion coefficients of the wiring pattern portion 22B and the resin film portion 22A are substantially equal, the elongation amount is L1b = L1′b≈L2b. Therefore, the forces Fb and F′b that the wiring pattern portion receives from the resin film portion at the two boundary surfaces between the resin film portion and the wiring pattern portion are both substantially equal to zero. For this reason, since no force is generated in the bending direction, the elastic substrate does not bend even if there is a difference in thickness between the left and right resin film portions.
As described above, the difference between the linear expansion coefficient of the wiring pattern member material of the elastic substrate 22 and the linear expansion coefficient of the resin film member material on both sides in the wiring pattern portion thickness direction is approximately 1 × 10 ⁻⁵ [cm / cm / ° C.] or less. By selecting a combination of materials, the difference in relative expansion and contraction in the surface direction between the wiring pattern part of the elastic substrate and the resin film part due to thermal expansion is reduced, and the surface verticality due to the relative thickness error of the double-sided resin film part It is possible to prevent the elastic substrate from being bent in the direction. In addition, as one combination of the wiring pattern member quality and the resin film material quality on both sides in the thickness direction of the wiring pattern portion, the wiring pattern portion has a linear expansion coefficient of about 1.7 × 10 ⁻⁵ [cm / cm / cm at normal temperature. [° C.] copper and polyimide having a linear expansion coefficient of 1.2 × 10 ⁻⁵ [cm / cm / ° C.] at room temperature may be used for the resin film portion.

  The necessary bending elastic force in the tangential direction of the elastic substrate 22 is a value that is naturally determined by the specifications of the objective lens driving device 1 and the design of each component, but does not bother producing an elastic substrate having the necessary elastic force. In both cases, as shown in the example of FIG. 1 (c), the reinforcing elastic plate 22C having an appropriate bending elastic force is fixed to both outer sides in the thickness direction of the existing elastic substrate, so that the required bending elastic force can be obtained. An elastic substrate can be realized. At this time, as shown in FIG. 2 (c), the reinforcing plate 22C of the same material, the same thickness, and the same shape is fixed to each side surface in the thickness direction of the elastic substrate 22, so that Create a new elastic substrate with a specific thickness, with the desired amount of flexural elasticity, while preventing the elastic substrate from bending in the direction perpendicular to the surface by making the amount of expansion symmetrical. This can be realized without any cost, so the cost can be reduced. Further, by making the reinforcing plate 22C the same material as the resin film portion 22A of the elastic substrate, similar expansion and contraction in the surface direction of the elastic substrate and the reinforcing plate due to thermal expansion is performed in the same manner as the principle described with reference to FIG. By reducing the difference in amount, it is possible to prevent the elastic substrate from being bent in the direction perpendicular to the plane due to the relative thickness error of the double-sided resin film portion.

Next, a second embodiment of the present invention will be described.
FIGS. 3A, 3B, 3C and 3D show an objective lens driving apparatus according to the second embodiment. 3A is a plan view of the objective lens driving device according to the present embodiment, FIG. 3B is a side view of the objective lens driving device viewed from the tracking direction, and FIG. 3C is a tangential direction of the elastic substrate. FIG. 3D is a cross-sectional configuration diagram (enlarged) of the elastic substrate in the thickness direction.
In the objective lens driving device according to the first embodiment, the movable portion 2 is supported from both sides of the tangential direction by the elastic support members 30 stretched on both the left and right sides, whereas the objective of the present embodiment is used. In the lens driving device 1, the movable portion 2 is supported by the elastic support member 30 only from one side in the tangential direction.
The objective lens driving device 1 is movable by connecting the movable portion 2, the fixed portion 20 disposed on the shoulder side of the movable portion 2 in the tangential direction with a predetermined gap therebetween, and the fixed portion 20 and the movable portion 2. It consists of four elastic support members 30 made of a material having elasticity and conductivity, such as metal, which floats and holds the portion 2 in a movable state.
The movable unit 2 includes an objective lens 3 that faces a recording surface of an optical disk (not shown), an objective lens holder 4 that holds the objective lens 3 on the upper surface in the focusing direction, and a drive that is held on both side surfaces in the tangential direction of the objective lens holder 4. It consists of a coil 5 and the like. Moreover, the movable part 2 fixes one end of each elastic support member 30 to the projecting member 2a projecting from both sides in the tracking direction, and each of the four elastic support members 30 extends symmetrically in both tangential directions. The other end is fixed to the part 20 side.

The fixing portion 20 includes a fixing member 21 and an elastic substrate 22 having an intermediate portion 22 a fixed to the outer surface of the fixing member 21, and the other end portion of each elastic support member 30 is fixed to the elastic substrate 22. ing. The elastic substrate 22 is in a free state at both ends in the tracking direction (elastic deformation part 22b) that are not fixed by the fixing member 21, and the other end part of each elastic support member 30 is connected to the elastic deformation part 22b in the free state. Each is fixed. The elastic substrate 22 has a T shape as shown in FIG. 3C, and the end portion on the lower side in the focusing direction is a terminal portion 22c as a conductor exposed portion. Further, the other end portion of each elastic support member 30 is fixed to a land portion (conductor exposed portion) 22b ′ as a conductor exposed portion provided on the elastic deformation portion 22b of the elastic substrate 22 by solder or the like. That is, the elastic deformation portion 22b is provided with a land portion 22b ', and a hole into which the other end portion of the elastic support member can be inserted is provided at the center of the land portion, and the other end portion of the elastic support member is provided at the center of the land portion. It is inserted into a hole and electrically connected by solder. With such a configuration, a current can be supplied from the terminal portion 22 c of the elastic substrate 22 to the drive coil 5 fixed to the movable portion 2.
A part of the elastic support member 30 is inserted through a through hole provided in the fixing member 21 and passes therethrough. As a result, the movable portion 2 is electrically connected to the elastic substrate 22 via the plurality of conductive elastic support members 30 and mechanically supported via the fixed member 21 to be operable. ing.
Each elastic support member 30 is arranged on one side in the tangential direction of the movable portion 2 such that its axis extends in the tangential direction, and each one end portion is an end point of the drive coil 5 connected to the movable portion 2 as described above. Electrically connected. The other end of each elastic support member 30 is connected to each elastic deformation portion 22b of the elastic substrate 22 and electrically connected to a land portion 22b ′ of the elastic substrate. The elastic substrate 22 exists in a plane including the focusing direction and the tracking direction on both sides of the tangential direction, has an intermediate portion 22a fixed to the fixing member 21 near the center of the tracking direction, and tangential on both sides of the tracking direction of the intermediate portion 22a. It has an elastically deformable portion 22b that can be displaced in the direction, and the other end of the elastic support member 30 is electrically and mechanically connected to the elastically deformable portion 22b.

As shown in FIG. 3D, the elastic substrate 22 has a configuration in which a wiring pattern 22B as a conductive portion is sandwiched between two insulating resin films 22A, and an electric current from the outside is provided below the intermediate portion 22a. The terminal part 22c which is an entrance / exit is provided. The resin film 22A is removed only in portions corresponding to the land portions 22b ′ and the terminal portions 22c, and the wiring pattern 22B (conductive portion) is exposed.
That is, resin films 22A having the same material, outer shape, and thickness are attached to both sides in the thickness direction of the wiring pattern 22B of the elastic substrate 22, and the terminal portion 22c and the land portion 22b ′ as wiring portions are adhered. At the same time that the entire surface of the conductive portion 22B is covered, this outer shape forms the outer shape of the elastic substrate.
In addition, one rising portion of a substantially U-shaped yoke base 26 is fixed to the inner surface of the fixing member 21 disposed on one side of the movable portion 2 in the tangential direction, and the two rising portions of the yoke base 26 are fixed. The driving magnets 25 are fixed to the inner side surfaces of the movable parts 2 and are arranged opposite to the driving coils 5 arranged on both sides of the movable part 2. Then, the current flowing through the drive coil 5 and the magnetic flux generated by the drive magnet 25 arranged facing the drive coil 5 are combined to generate a Lorentz force in the drive coil 5 so that the movable part 2 can It is possible to drive in the direction.

  Here, the assembly of the elastic support member 30 and the elastic substrate 22 of the objective lens driving device 1 is performed as follows. In other words, the movable portion 2 held by an unillustrated objective lens driving device assembly jig, the elastic support member 30, and the elastic substrate 22 having the fixed portion (intermediate portion) 22 a fixed beforehand to the fixed member 21 are respectively predetermined. Placed in position. The movable part 2 and the elastic support member 30 are fixed first, and then the elastic support member 30 and the elastic substrate 22 are fixed. One end of the elastic support member 30 on the elastic substrate 22 side is inserted into each of a plurality of holes at the center of the land portion in the elastic deformation portion of the elastic substrate, and the land portion is elastically supported by soldering. The member and the elastic substrate are fixed. At this time, the elastic substrate receives heat, but the elastic substrate is symmetrical in material, thickness, and shape with the wiring pattern portion being the center in the thickness direction (tangential direction), so the center is in the thickness direction. On the other hand, the linear expansion coefficient is symmetrical, and the amount of expansion in the surface direction at the time of thermal expansion is also symmetrical, so that the elastic deformation portion of the elastic substrate can be assembled without causing deflection in the surface vertical direction. Thereby, the assembly position accuracy of the movable part in the tangential direction can be improved. In the above example, a moving coil type objective lens driving device having a driving coil mounted on the movable part is used. However, a moving magnet type objective lens driving device has the same effect.

Next, an objective lens driving device according to a third embodiment of the present invention will be described based on FIGS. 4 (a) and 4 (b) and FIGS. 5 (a), 5 (b) and 5 (c). FIG. 4A is a plan view of the objective lens driving device of the present embodiment, and FIG. 4B is a side view of the objective lens driving device viewed from the tracking direction. The objective lens driving device 1 according to the present embodiment is the same as that of the first embodiment except for the shape of the elastic substrate 22 and the support structure. Is omitted.
The present embodiment is characterized in the procedure for assembling the elastic support member and the elastic substrate of the objective lens driving device shown in FIG.
That is, this assembly is performed as follows. First, an elastic substrate 22 in which a fixed portion (intermediate portion 22a) is fixed in advance to a movable portion 2, an elastic support member 30, and a fixed member 21 held by an unillustrated objective lens driving device assembling jig except for a part. Are arranged at predetermined positions as shown in FIG.
The elastic substrate 22 is restricted from moving in the tangential direction while being elastically deformed in an arc shape in advance toward the tangential movable portion by the elastic substrate urging jig 35. The movable portion 2 and the elastic support member 30 are fixed first, and then the elastic support member 30 and the elastic substrate 22 are fixed.
Each elastic substrate 22 whose movement in the tangential direction is regulated while being elastically deformed toward the tangential direction movable portion side is removed from the jig 35 after the assembly is completed, and thereby the elastic deformation restoring force causes the tangential direction. An attempt is made to return outward (in the direction of arrow A in FIG. 5B). Accordingly, the elastic support member 30 having one end fixed to the elastic substrate 22 is also pulled outward in the tangential direction, so that the movable portion 2 fixed to the elastic support member 30 is pulled to both sides in the tangential direction (see FIG. 5 (b) (c)). As a result, the movable portion 2 that has been bent downward in the focus direction due to its own weight is pulled up to the upper side in the focus direction (the state shown in FIG. 5C is obtained as a result of the shape restoration in the arrow B direction in FIG. 5B). Can do. By appropriately selecting and adjusting the bending rigidity and the biasing amount of the elastic substrate 22, it is possible to cancel the downward displacement in the focusing direction due to its own weight in the neutral state of the movable part, which was a conventional problem. As a result, in the assembly of the objective lens driving device, the position accuracy of the movable portion 2 in the neutral state (no load state) can be improved, the DC offset current can be reduced, and the DC current distribution and AC current distribution of the other axis can be achieved. Can be increased.
In the above description, a moving coil type objective lens driving device in which a driving coil is mounted on the movable part is used. However, a moving magnet type objective lens driving device is similarly effective.

Next, an objective lens driving device according to a fourth embodiment of the present invention will be described based on FIGS. 6 (a), 6 (b), and 6 (c). 6A is a plan view of the objective lens driving device of the present embodiment, FIG. 6B is a side view of the objective lens driving device viewed from the tracking direction, and FIG. 6C is an explanatory view of the assembling method.
The objective lens driving device 1 according to the present embodiment is the same as that of the first embodiment except for the shape of the elastic substrate 22 and the support structure. Is omitted.
A characteristic configuration of the present invention resides in a method of assembling the elastic support member and the elastic substrate of the objective lens driving device.
FIG. 6C shows the movable portion 2, the elastic support member 30, and the elastic substrate 22 in which the fixed portion 22a is fixed to the fixing member in advance, respectively, held by an objective lens driving device assembly jig (not shown) except for a part. As shown in FIG. The elastic substrate 22 is restricted in movement in the tangential direction by an elastic substrate deflection regulating jig 36 so as not to bend in the tangential direction. In assembling, the movable portion 2 and the elastic support member 30 are fixed first, and then the elastic support member 30 and the elastic substrate 22 are fixed. One end of the elastic support member 30 on the elastic substrate 22 side is inserted into each of a plurality of holes at the center of the land portion 22b ′ in the elastic deformation portion 22b of the elastic substrate 22, and this land portion is soldered. By doing so, the elastic support member and the elastic substrate are fixed. At this time, the elastic substrate 22 receives heat. However, since the movement in the tangential direction is restricted by the jig 36, the elastic substrate 22 is assembled without causing deflection in the surface vertical direction of the elastic deformation portion 22b of the elastic substrate. Can be attached. As a result, in the assembly of the objective lens driving device, the position accuracy of the movable part in the focus direction in the neutral state (no load state) can be improved, the DC offset current can be reduced, and the DC current distribution and AC current distribution of the other axes can be reduced. Increase is possible. In the description of the assembling method, a moving coil type objective lens driving device in which a driving coil is mounted on the movable part is used. However, a moving magnet type objective lens driving device is also effective.

Next, an assembling method according to the fifth embodiment of the present invention will be described with reference to FIG.
The configuration of the objective lens driving device completed by this assembling method is the same as that shown in FIGS. 6 (a) and 6 (b). Therefore, the illustration will be omitted and will be described with reference to FIG.
Here, the elastic support member 30 and the elastic substrate 22 are assembled as follows. First, the movable portion 2, the elastic support member 30, and the elastic substrate 22 in which the fixed portion 22a is fixed in advance to the fixing member 21 are arranged at predetermined positions, respectively, held by an objective lens driving device assembly jig (not shown). . The movable part 2 and the elastic support member 30 are fixed first, and then the elastic support member 30 and the elastic substrate 22 are fixed. One end of the elastic support member 30 on the elastic substrate side is inserted into each of a plurality of holes at the center of the land portion 22b ′ in the elastic deformation portion 22b of the elastic substrate, and this land portion is soldered. The elastic support member and the elastic substrate are fixed to each other. At this time, the elastic substrate is heated to be deformed into an arc shape on the movable portion side (arrow C direction) in the tangential direction as shown in FIG. 7A, and in this state, the elastic substrate is fixed to the elastic support member by solder. . After that, when heat is released, the deformation of the elastic substrate 22 in the tangential direction tries to return (in the direction of arrow D in FIG. 7B), and accordingly, the elastic support member 30 fixed to the elastic substrate 22 also moves outward in the tangential direction. Since it is pulled, the movable part fixed to the elastic support member is pulled to both sides in the tangential direction (FIG. 7 (b) → (c)). As a result, the movable portion 2 that has been bent downward in the focus direction due to its own weight can be configured as shown in FIG. 7C as a result of returning the shape to the upper side in the focus direction (the direction of arrow E in FIG. 7B). . At this time, by appropriately selecting and adjusting the bending rigidity of the elastic substrate 22 and the amount of deformation due to heating, it is possible to cancel the downward displacement in the focusing direction due to its own weight in the neutral state of the movable part, which was a drawback of the conventional example.
As described above, by utilizing the reversible deformation in the direction perpendicular to the surface by heating the elastic deformation portion 22b of the elastic substrate 22, it is possible to improve the focus direction position accuracy of the movable portion 2 in the neutral state (no load state). The DC offset current can be reduced, and the DC current distribution and the AC current distribution on the other axis can be increased.
In the above description, a moving coil type objective lens driving device having a driving coil mounted on the movable part is used. However, a moving magnet type objective lens driving device is also effective.

Next, an optical pickup device according to a sixth embodiment of the present invention is shown in FIG. Light emitted from the light source 40 mounted on the optical pickup device PU passes through the coupling lens 41 and the beam splitter 42 and is bent by the rising mirror 43. The light bent by the rising mirror 43 enters the objective lens 12 of the objective lens driving device 1 (not shown) mounted on the optical pickup and forms a spot on the recording surface of the optical disc (not shown). The reflected light of the spot changes its direction and direction from the beam splitter 42, passes through the detection lens 44 and the cylindrical lens 45, and then enters a light receiver 46 as a light detector. By driving the focusing coil 20, the tracking coil 21 and the radial tilt coil 22 of the objective lens driving device 1 based on the signal obtained by the light receiver 46, the objective lens 12 is made to follow the optical disk, so that the optical disk Information can be obtained. Here, the objective lens driving device 1 mounted on the optical pickup device PU can be mounted with the objective lens driving device described in the first to fifth embodiments. Since each objective lens driving device 1 has high acceleration sensitivity performance, it is possible to provide an optical pickup device that can obtain a good signal even when the speed is increased.
An optical disk drive device according to a seventh embodiment of the present invention is shown in FIG. FIG. 9 shows a state where the pickup module 51 is installed in the optical disc drive device 50. A spindle motor 53 that rotates the optical disk 52 is fixed to the pickup module 51. An optical pickup device PU is mounted on the seek rail 54 attached to the pickup module 51. The optical pickup device PU can move on the seek rail 54 in the radial direction of the optical disk 52. Here, the optical pickup device PU mounted on the optical disk drive device 50 has the same configuration as the optical pickup device taken up in the sixth embodiment. Since the objective lens driving device 1 equipped in the optical pickup device PU has high acceleration sensitivity performance, a good signal can be obtained even if the speed is increased. Therefore, this optical disk drive device 50 can read and write data satisfactorily.

(A) thru | or (d) is explanatory drawing of the objective lens drive device which concerns on the 1st Embodiment of this invention, (a) is a top view of an objective lens drive device, (b) tracks an objective lens drive device. The side view seen from the direction, (c) is the figure which looked at the elastic substrate from the tangential direction, (d) is the thickness direction cross-sectional block diagram (enlarged) of the elastic substrate. It is explanatory drawing of the objective lens drive device which concerns on 1st Embodiment, (a) (b) and (c) are thickness direction sectional drawings of an elastic substrate. (A), (b), (c) and (d) are objective lens driving devices according to the second embodiment, (a) is a plan view of the objective lens driving device according to the present embodiment, and (b) is a plan view. The side view which looked at the objective lens drive device from the tracking direction, (c) is the figure which looked at the elastic substrate from the tangential direction, (d) is the thickness direction cross-section block diagram (enlargement) of the elastic substrate. (A), (b), (c), and (d) are objective lens driving devices according to the third embodiment, (a) is a plan view of the objective lens driving device according to the present embodiment, and (b) is a plan view. The side view which looked at the objective lens drive device from the tracking direction, (c) is the figure which looked at the elastic substrate from the tangential direction, (d) is the thickness direction cross-section block diagram (enlargement) of the elastic substrate. (A) (b) And (c) is explanatory drawing of the assembly method which concerns on 3rd Embodiment. (A) is a plan view of an objective lens driving device according to a fourth embodiment of the present embodiment, (b) is a side view of the objective lens driving device viewed from the tracking direction, and (c) is an explanatory view of an assembling method. . (A) (b) And (c) is explanatory drawing of the 5th Embodiment of this invention. Explanatory drawing of the optical pick-up apparatus which concerns on the 6th Embodiment of this invention. Explanatory drawing which shows the state by which the pick-up module is installed in the optical disk drive device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Objective lens drive device, 2 Movable part, 2a Projection part, 3 Objective lens, 4 Objective lens holder, 5 Drive coil, 20 Fixing part, 21 Fixing member, 22 Elastic board, 22a Intermediate part (fixed part), 22b Elastic deformation part, 22b 'land part, 22c terminal part, 22A Insulating resin film (resin part), 22B Wiring pattern part (wiring part), 30 Elastic support member, 35, 36 Jig

Claims (9)

An objective lens for condensing light on a recording / reproducing surface of an optical disc, an objective lens holder for holding the objective lens, and a plurality of elastic supports that are fixed to one end of the objective lens holder and operably support the objective lens holder A member, a fixing member that supports the other part of the elastic support member, and a driving unit that drives the objective lens holder to correct the objective lens,
An elastically deformable portion that exists in a plane including the focusing direction and the tracking direction, has a fixed portion fixed to the fixing member near the center of the tracking direction, and is capable of displacing both sides of the fixed portion in the tangential direction. And an elastic substrate to which one end portions of the plurality of elastic support members extending in a tangential direction with respect to the elastic deformation portion are coupled, and an objective lens driving device comprising:
The objective lens driving device according to claim 1, wherein the elastic substrate is symmetrical in material, thickness, and shape with respect to a center in a thickness direction. The elastic substrate has a wiring portion made of a conductive material at the center in the thickness direction, and includes resin portions having the same material, thickness and shape on both sides in the thickness direction of the wiring portion, and the value of the linear expansion coefficient of the wiring portion The objective lens driving device according to claim 1, wherein a material having a difference between the linear expansion coefficient of the resin portion and a value of 1 × 10 ⁻⁵ [cm / cm / ° C.] or less is selected in combination.   The objective lens drive according to claim 1, wherein the elastic substrate has reinforcing plates having the same material, the same thickness, and the same shape on both side surfaces in the thickness direction of the elastic substrate. apparatus.   The objective lens driving device according to claim 3, wherein the reinforcing plate is made of the same material as the resin portion of the elastic substrate. An objective lens for condensing light on a recording / reproducing surface of an optical disc, an objective lens holder for holding the objective lens, and a plurality of elastic supports that are fixed to one end of the objective lens holder and operably support the objective lens holder A member, a fixing member that supports the other part of the elastic support member, and a driving unit that drives the objective lens holder to correct the objective lens,
An elastically deformable portion that exists in a plane including the focusing direction and the tracking direction, has a fixed portion fixed to the fixing member near the center of the tracking direction, and is capable of displacing both sides of the fixed portion in the tangential direction. And an elastic substrate to which one end portions of the plurality of elastic support members extending in a tangential direction with respect to the elastic deformation portion are coupled, and an objective lens driving device comprising:
An assembling method of an objective lens driving device, wherein the elastic support member and the elastic substrate are fixed in a state where the elastic substrate is elastically deformed toward the objective lens holder in the tangential direction by an external force. An objective lens for condensing light on a recording / reproducing surface of an optical disc, an objective lens holder for holding the objective lens, and a plurality of elastic supports that are fixed to one end of the objective lens holder and operably support the objective lens holder A member, a fixing member that supports the other part of the elastic support member, and a driving unit that drives the objective lens holder to correct the objective lens,
An elastically deformable portion that exists in a plane including the focusing direction and the tracking direction, has a fixed portion fixed to the fixing member near the center of the tracking direction, and is capable of displacing both sides of the fixed portion in the tangential direction. And an elastic substrate to which one end portions of the plurality of elastic support members extending in a tangential direction with respect to the elastic deformation portion are coupled, and an objective lens driving device comprising:
An assembling method of an objective lens driving device, wherein the elastic support member and the elastic substrate are fixed in a state where the elastic substrate is regulated so as not to bend in the tangential direction. An objective lens for condensing light on a recording / reproducing surface of an optical disc, an objective lens holder for holding the objective lens, and a plurality of elastic supports that are fixed to one end of the objective lens holder and operably support the objective lens holder A member, a fixing member that supports the other part of the elastic support member, and a driving unit that drives the objective lens holder to correct the objective lens,
An elastically deformable portion that exists in a plane including the focusing direction and the tracking direction, has a fixed portion fixed to the fixing member near the center of the tracking direction, and is capable of displacing both sides of the fixed portion in the tangential direction. And an elastic substrate to which one end portions of the plurality of elastic support members extending in a tangential direction with respect to the elastic deformation portion are coupled, and an objective lens driving device comprising:
An objective lens characterized in that the elastic substrate is asymmetric in material, thickness and shape with respect to the center in the thickness direction, and has a characteristic of reversibly deforming toward the objective lens holder side in the tangential direction by heating. Drive device. A light source that emits a luminous flux;
The objective lens driving device according to claim 1 or 4 or 7, or the objective lens driving device assembled by the assembling method according to claim 5 or 6,
An optical system that enters the luminous flux into the objective lens in the objective lens driving device, reflects the reflected light on the recording / reproducing surface, and guides return light after passing through the objective lens to a predetermined light receiving position;
And an optical detector disposed at the light receiving position. An optical pickup device according to claim 8,
A seek mechanism for moving the optical pickup device in a radial direction of the optical disc;
A spindle motor that rotates the optical disc;
An optical disk drive device comprising: a processing device that performs at least reproduction among recording, reproduction, and erasure of the information using an output signal of the optical pickup device.

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