JP3916190B2 - Objective lens driving device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an objective lens driving device of an optical pickup device that projects and reads information optically by projecting a light spot onto a recording medium on a disk.
[0002]
[Prior art]
In general, an optical pickup device includes an objective lens driving device including an objective lens and an optical system that transmits and receives light to and from the objective lens. The objective lens driving device is arranged on the mounting base of the optical system block.
[0003]
As shown in FIG. 7, a general objective lens driving device includes a movable unit 1 including an objective lens 11, a focus coil 12, and a tracking coil 13, a fixed unit 2 including a magnetic circuit (magnet or the like) 21, Both ends are fixed to the movable part 1 and the fixed part 2 and are composed of four elastic support members 3 supporting the movable part 1 in a cantilever manner. The elastic support member 3 that is a metallic wire is distributed to the right and left two by two with respect to the objective lens 11, and is arranged vertically on the left and right sides, one end of which is the left and right of the lens holder 14 to which the objective lens 11 is attached. The other end of the holder substrate 15 provided on the side surface is fixed to a base substrate 23 erected on the base 22 by soldering. The fixing portion 2 is arranged so that the elastic support member 3 is parallel to the tangential direction (the tangential direction of the disk).
[0004]
The movable portion 1 shifts in the focus direction (direction perpendicular to the disk) by energizing the focus coil 12 and in the radial direction (disk radial direction) by energizing the tracking coil 13. In order to control the vibration of the movable portion 1, as shown in FIG. 8, a damper case 24 is provided in front of the base substrate 23 to which the other end of the elastic support member 3 is fixed, and the damper case 24 and the base substrate 23 are mounted. The other end of the elastic support member 3 is fixed to the base substrate 23 by soldering, and the damper case 24 is filled with the gel-like damping material 25 and attached to the elastic support member 3. This is based on the deformation and viscous flow of the gel-like damping material 25 due to the shift of the elastic support member 3 that is partially disposed in the filled gel-like damping material 25 and attached to the gel-like damping material 25. Thus, damping is performed (for example, JP-A-2-232824).
[0005]
[Problems to be solved by the invention]
In this prior art, the four elastic support members 3 are movable so that the movable portion 1 does not tilt when the movable portion 1 is shifted in the focus direction and the radial direction, that is, the objective lens 11 does not tilt. The interval between the fixed portion on the part 1 side and the fixed end on the fixed portion 2 side is set to be equal so that they are parallel in the vertical and horizontal directions. Further, assuming that the elastic support member 3 is fixed at a predetermined position, the amount of the gel-like damping material 25 in the left and right damper cases 24 is set equal.
[0006]
Therefore, if even one of the four elastic support members 3 is misaligned, for example, the distance between the vertical elastic support members 3 in the radial direction + side movable portion 1 and the vertical elastic support members in the radial direction−side movable portion 1 are used. If the distance 3 is different, the left and right are unbalanced with the objective lens 11 as the center. Therefore, as shown in FIG. 9, when the movable part 1 that is horizontal at the neutral position is shifted in the focus direction, a moment is generated around the center of gravity of the movable part 1, and the movable part 1 is radial as shown in FIG. Has a tilt in the direction. Therefore, when the movable part 1 is shifted in the focus direction, for example, the objective lens 11 has an inclination, generates coma aberration, and deteriorates the jitter of the read signal.
[0007]
Therefore, in order to prevent this inclination, it is necessary to position the elastic support member 3 with high accuracy. However, it is quite difficult to perform such positioning in the process, and there are some cases that have an inclination. As a process of correcting this, there is a method of re-soldering the elastic support member 3, but this is not always corrected due to the yield, and the reliability of the solder portion of the elastic support member 3 is not necessarily corrected. There is a problem of concern.
[0008]
The present invention has been made for the purpose of solving such problems of the prior art.
[0009]
[Means for Solving the Problems]
Means for solving the above problems will be described below with reference to FIG. 1 corresponding to one embodiment. In the present invention, the movable part 1 including the objective lens 11 is distributed to the left and right by a plurality around the objective lens 11 and supported by the fixed part 2 by a plurality of elastic support members 3 arranged vertically on the left and right. In the objective lens driving apparatus, the tamping is attached to the elastic support member 3 by adding an inclination adjusting damping material to any of the damping materials 25L and 25R in the left and right existing damper cases 24L and 24R of the fixed portion 2. The amount of the material is set so as to be different on the left and right.
[0010]
In such a configuration, when the movable part 1 is shifted in the focus direction + side, when the movable part 1 is inclined in the radial direction-side, the damper case 24R on the radial direction + side corresponds to the inclination. The inclination is corrected by adding an appropriate amount of damping material so that the amounts of the damping materials 25L and 25R are different.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, 1 is a movable part, 2 is a fixed part, 3 is an elastic support member, 24L is a damper case on the left side (radial direction-side), 24R is a damper case on the right side (radial direction + side), and 25L is a damper case. A damping material filled in 24L and 25R are damping materials filled in the damper case 24R.
[0012]
The relationship between the amount of damping material added here and the inclination angle that can be corrected will be described. FIG. 2 shows the results of an experiment conducted to determine the relationship between the amount of damping material to be added and the inclination angle that can be corrected. This relationship is different depending on the type of the elastic support member 3 and the spring constant, the volume of the damper cases 24L and 24R, the type of the damping materials 25L and 25R, the initial filling amount, and the like. . Various materials can be used as the damping materials 25L and 25R, but gel materials are preferable, and silicone-based and modified acrylate-based gel-damping materials are particularly preferable. In the following description of the present invention, a silicone-based gel damping material was used.
[0013]
The elastic support member 3 has four wires with a diameter of 80 μm, the length from the movable part 1 side fixed end to the fixed part 2 side fixed end is 9 mm, and the left and right damper cases 24L and 24R are filled with 7.6 mg of damping material One damper case 24L or 24R is used with two upper and lower wires. The damper case 24R was filled with 6.1 mg of the damping material 25R, and the radial inclination when the movable part was shifted by +0.5 mm in the focus direction was measured while adding the damping material 25L to the damper case 24L.
[0014]
The horizontal axis in FIG. 2 is the amount of the damping material 25L filled in the damper case 24L, and the vertical axis is the radial inclination when the movable part 1 is shifted +0.5 mm in the focus direction. From this inclination, it can be seen that the amount of damping material decreases. That is, when the amount of the damping material 25R on the right side (radial direction + side) is larger than the amount of the damping material 25L on the left side (radial direction-side), it is lowered to the right (inclined to the radial direction + side) and vice versa. In the case of, it goes to the left (inclined to the radial direction-side).
[0015]
The amount of damping material to be added and the radial inclination are substantially proportional, and the proportionality constant can be calculated as 4.2 minutes / mg.
[0016]
From the result of FIG. 2, the relationship between the amount of additional damping material shown in FIG. 3 and the inclination angle that can be corrected can be derived. For example, when the inclination of the movable part 1 when the prepared sample is shifted +0.5 mm in the focus direction is 4.2 minutes in the radial direction + side, 1.0 mg of damping is applied to the radial case-side damper case 24L. If a material is added, the inclination of the movable part 1 can be corrected and the inclination angle can be made zero.
[0017]
Therefore, an equal or substantially equal amount of damping material is put in the damper cases 24L and 24R, the inclination of the movable portion 1 when +0.5 mm is shifted in the focus direction, and either one of them is determined according to the inclination. If a damping material for tilt adjustment is added to the damper case 24L or 24R so that the amounts of the damping materials 25L and 25R are different, the tilt of the movable portion 1 in the radial direction is eliminated.
[0018]
The damping materials 24L and 24R may be placed in the damper cases 24L and 24R, and the amount of the damping materials 25L and 25R may be varied by inserting the damping material while measuring the objective lens tilt characteristics.
[0019]
As described above, the damping adjustment damping material is added to the damper case 24L or 24R on the fixed portion 2 side. However, as shown in FIG. 4, the tilt adjustment damper cases 4 are provided on the left and right sides on the movable portion 1 side. The same effect can be obtained even if the damping adjusting damping material 5 is added to both. Although the tilt adjustment damper case 4 is provided on the left and right side surfaces of the lens holder 14, the holder substrate 15 may be expanded and fixed to the holder substrate 15. Further, although there is one inclination adjusting damper case 4 for the two upper and lower elastic support members 3, it may be provided for each elastic support member 3. The reason why the tilt adjusting damping material 5 is added to both the tilt adjusting damper cases 4 is because it is assumed that the tilt adjusting damping material 5 is not added to the tilt adjusting damper case 4 from the beginning. When added from the beginning, it is sufficient to add the inclination adjusting damping material 5 to any one of the inclination adjusting damper cases 4.
[0020]
Further, as shown in FIG. 5, the same effect can be obtained by providing the tilt adjustment damper cases 6 that stand independently on the base 22 on the left and right sides of the fixed portion 2 and adding the tilt adjustment damping material 7 to one or both of them. It is done. Although there is one inclination adjusting damper case 6 for the two upper and lower elastic support members 3, each of the elastic support members 3 may be provided vertically.
[0021]
Further, as shown in FIG. 6, the inclination adjusting damper case 8 may be directly applied to the elastic support member 3 without being provided with the inclination adjusting damper case and held by the movable portion 1. The application place is the left and right side surfaces of the lens holder 14 in the figure, but the holder substrate 15 may be expanded to be the holder substrate 15. In the figure, two are applied to the same place. For example, the upper elastic support member 3 is applied to a different part from the movable part 1 side, and the lower elastic support member 3 is applied to a different part from the fixed part 2 side. Also good. Further, the damping adjusting damping material 8 may be applied to one or both of the elastic support members 3.
[0022]
The type of the damping material for tilt adjustment may be different from that of the initially filled damping material.
[0023]
Since the amount of the damping material in the damper case 24L or 24R can be reduced by dispersing the damping material in the damping material in the damper case 24L or 24R and the damping material for tilt adjustment, the inside of the damper case 24L or 24R The depth of the can be reduced, and shortening in the tangential shell direction can be expected.
[0024]
An unbalance in which the distance between the upper and lower elastic support members 3 of the radial direction + side movable part 1 and the distance between the upper and lower elastic support members 3 of the radial direction−side movable part 1 is different by adding an inclination adjusting damping material, It disappears by changing the constant. Therefore, the elastic support wire 3 in the radial direction + side and the elastic support member 3 in the radial direction-side are equal. As a result, when shifted in the focus direction, the elastic support member 3 works equally and moves horizontally, so that the movable portion 1 does not tilt in the radial direction.
[0025]
Moreover, not only the inclination which arises by the dimension shift | offset | difference of the elastic support member in an assembly but the inclination which generate | occur | produces, for example because the magnet position has shifted | deviated to the radial direction can be corrected by the same method.
[0026]
Furthermore, even if there is a tendency to always lean to either side due to the jigging, etc. in assembly, the jig is not modified, and a damper case is provided in advance, and an appropriate amount of damping material that is different on the left and right sides can be inserted. It is also possible to cancel the habit.
[0027]
The present invention has been described with respect to an objective lens driving device that is cantilevered by a fixed portion by four elastic support members that are distributed two by two around the objective lens and that are arranged vertically on the left and right. Can be applied to an objective lens driving device that is supported in a cantilevered manner by the six elastic support members that are distributed to the left and right by three and are arranged vertically on the left and right sides. The support method can be applied not only to a cantilever but also to a both-end support.
[0028]
As described above, although the movable unit 1 has been described as an invention of an objective lens driving device that does not tilt in the radial direction even when the movable unit 1 is shifted in the focus direction, at the same time, the present invention is movable even if it is shifted in the focus direction. Part 1 is an invention of a method of manufacturing an objective lens driving device that does not tilt in the radial direction. That is, the movable part provided with the objective lens is divided into a plurality of left and right around the objective lens, and the objective lens driving device supported by the fixed part by a plurality of elastic support members arranged vertically on the left and right. In the manufacturing method, after inspecting the objective lens tilt characteristics, an inclination adjusting damping material is added to the damping material that is disposed and fixed between the fixing points at both ends of the elastic support member and adhered to the elastic support member according to the tilt. To correct the tilt.
[0029]
【The invention's effect】
As described above, according to the present invention, the movable portion provided with the objective lens is divided into a plurality of left and right about the objective lens, and the fixed portion is provided by the plurality of elastic support members arranged vertically on the left and right. In the supported objective lens driving device, the damping material for tilt adjustment is added to one of the damping materials in the existing damper case on the left and right sides of the fixed portion, and the amount of the tamping material attached to the elastic supporting member is It is characterized by having been set differently. Therefore, even if the movable part is shifted to the focus direction 10 side, the movable part does not tilt in the radial direction. Therefore, according to the present invention, it is not necessary to position the elastic support member with high accuracy in order to prevent the inclination, and re-soldering of the elastic support member and the solder portion of the elastic support member as a correction process accompanying high-accuracy positioning are performed. The effect that the concern about the reliability of is resolved.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of the present invention.
FIG. 2 is a diagram showing the relationship between the amount of damping material and the inclination in the radial direction.
FIG. 3 is a diagram showing a relationship between an amount of damping material to be added and a tilt angle that can be corrected.
FIG. 4 is a cross-sectional view showing another embodiment of the present invention.
FIG. 5 is a cross-sectional view showing another embodiment of the present invention.
FIG. 6 is a cross-sectional view showing another embodiment of the present invention.
FIG. 7 is a perspective view of a conventional objective lens driving device.
FIG. 8 is a cross-sectional view showing a state in which a conventional elastic support member is attached.
FIG. 9 is a front view showing a neutral state of the prior art.
FIG. 10 is a front view when the movable part of the prior art is shifted in the focus direction + side.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Movable part 2 Fixed part 3 Elastic support member 25L Damping material 25R Damping material

Claims (9)

In the objective lens driving device in which the movable part including the objective lens is divided into a plurality of left and right parts around the objective lens, and supported by the fixed part by a plurality of elastic support members arranged vertically on the left and right sides. An inclination adjusting damping material is added to any of the damping materials in the existing damper cases on the left and right of the fixed portion, and the amount of the tamping material adhering to the elastic support member is set to be different on the left and right. Objective lens drive device In the objective lens driving device in which the movable part including the objective lens is divided into a plurality of left and right parts around the objective lens, and supported by the fixed part by a plurality of elastic support members arranged vertically on the left and right sides. Inclination adjustment damper cases are provided on the left and right of the movable part, and the amount of tamping material adhering to the elastic support member is set to be different on the left and right sides by adding the inclination adjustment damping material to one or both of them. an objective lens driving device, characterized in that In the objective lens driving device in which the movable part including the objective lens is divided into a plurality of left and right parts around the objective lens, and supported by the fixed part by a plurality of elastic support members arranged vertically on the left and right sides. Inclination adjustment damper cases are provided on the left and right sides of the fixed part, and the amount of tamping material adhering to the elastic support member is set to be different on the left and right sides by adding the inclination adjustment damping material to one or both of them. an objective lens driving device, characterized in that In the objective lens driving device in which the movable part including the objective lens is divided into a plurality of left and right parts around the objective lens, and supported by the fixed part by a plurality of elastic support members arranged vertically on the left and right sides. It is characterized in that the damping material for tilt adjustment is directly applied to the elastic support member, and the amount of the tamping material attached to the elastic support member is set so as to be different from right to left while being held by the movable part. Objective lens drive A method of manufacturing an objective lens driving device in which a movable part having an objective lens is distributed to the left and right by a plurality around the objective lens and supported by the fixed part by a plurality of elastic support members arranged vertically on the left and right Then, after the objective lens tilt characteristic inspection, in accordance with the tilt, a damping material for tilt adjustment is added to the damping material that is disposed and fixed between the fixing points at both ends of the elastic support member and adhered to the elastic support member, Method for manufacturing objective lens driving device characterized by correcting inclination 6. The method of manufacturing an objective lens driving device according to claim 5, wherein an inclination adjusting damping material is added to any of the damping materials in the existing damper cases on the left and right sides of the fixed portion. 6. The method of manufacturing an objective lens driving device according to claim 5, wherein a damper case for tilt adjustment is provided on the left and right sides of the movable part, and a damping material for tilt adjustment is added to one or both of them. 6. The method of manufacturing an objective lens driving device according to claim 5, wherein a damper case for tilt adjustment is provided on the left and right sides of the fixed portion, and a damping material for tilt adjustment is added to one or both of them. 6. The method of manufacturing an objective lens driving device according to claim 5, wherein a damping adjusting damping material is directly applied to the elastic support member and is held by the movable portion.

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