JP2004014025A - Objective lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that fitting position precision of a lens holder is affected by dispersion of an installation position of an assembly tool and a problem of workability since the assembly tool is required. <P>SOLUTION: Positioning members 7 and 8 having projections 7a and 8a inserted into an optical path hole 4 of the lens holder 2 are integrally formed in a frame 1, and the projections 7a and 8a are inserted into the optical path hole of the lens holder 2. Thus, the lens holder 2 is positioned with respect to the frame 1. A suspension member supporting the lens holder 2 so that it can be displaced with respect to the frame 1 in such a state is installed. Then, the positioning members 7 and 8 are removed. The suspension member is installed without using the assembly tool by improving installed position precision of the lens holder 2 with respect to the frame 1. Regulation of the lens holder 2 by the positioning members 7 and 8 is canceled in such a state. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an objective lens driving device provided in an optical head that reads signals from or writes signals to a signal recording medium such as a disk.
[0002]
[Prior art]
The objective lens driving device is generally configured such that a lens holder on which an objective lens is mounted is connected to a frame by a suspension member, whereby the lens holder is elastically supported so as to be displaceable with respect to the frame.
[0003]
In many cases, a suspension wire is used as the suspension member, and an objective lens driving device using the suspension wire as described above is configured such that one end of each of four suspension wires bridged in parallel with each other on a mounting plate attached to a frame. By fixing the suspension wire and the other end of each suspension wire to the lens holder, the lens holder is elastically supported by the suspension wire so as to be displaceable with respect to the frame.
[0004]
By the way, when assembling the objective lens driving device, when arranging suspension wires, each suspension wire is first inserted into each hole formed in the mounting plate, and then inserted into a hole provided in the lens holder. It is fixed by soldering or an adhesive with a mounting plate and a lens holder and installed.
[0005]
Further, an actuator movable portion is configured by attaching each of the focusing coil and tracking coil drive coils to the lens holder, and a permanent circuit that forms a magnetic circuit to form a magnetic field as designed on the effective side of each drive coil of the lens holder. The magnet and the magnetic yoke are placed on the lens holder.
[0006]
For these reasons, when installing the suspension member, it is necessary to install the lens holder at a predetermined position on the frame.
[0007]
[Problems to be solved by the invention]
By the way, when the lens holder is installed at a predetermined position on the frame, it has been performed using a special assembling jig.
[0008]
Therefore, the accuracy of the mounting position of the lens holder depends on the variation of the installation position of the assembling jig, and since the assembling jig is required, there is a problem in workability, and the assembling jig can be installed. Therefore, it was necessary to consider the shapes of the frame and the lens holder.
[0009]
In addition, since the mounting position accuracy of the lens holder cannot be ensured, the support positions of the suspension members on the lens holder side and the frame side on one end side and the other end side vary, and the positions where the suspension members are erected are unbalanced. For this reason, there has been a problem that the attitude of the objective lens changes when the objective lens is shifted during tracking or focusing, and the optical performance is degraded.
[0010]
[Means for Solving the Problems]
The present invention is characterized in that a positioning member having a projection inserted into an optical path hole for securing an optical path of an objective lens of a lens holder is integrally formed on a frame, and the projection is inserted into the optical path hole of the lens holder. Positioning the lens holder with respect to the frame, and suspending the suspension member between the frame and the lens holder so as to support the lens holder displaceably with respect to the frame in a state where the lens holder is positioned; The positioning member is removed from the lens holder while the lens holder is supported by the frame. In this way, the suspension member is installed on the frame and the lens holder without using an assembly jig by improving the accuracy of the installation position of the lens holder with respect to the frame, and the positioning member restricts the lens holder with this suspension member installed. I am trying to release it.
[0011]
【Example】
FIG. 1 is an exploded perspective view showing a developed state of a main part of the objective lens driving device according to the present invention from the bottom side. FIG. 2 is a perspective view showing an assembled state of the objective lens driving device shown in FIG. 4 is a perspective view showing the assembled state of the objective lens driving device shown in FIG. 1 from the top side, and FIG. 4 is a perspective view showing the completed state of the objective lens driving device shown in FIG. 1 from the top side.
[0012]
The frame 1 is integrally formed of a high-strength synthetic resin such as PPS (poly-phenylene-sulfur side) or polycarbonate, and is installed in an optical housing (not shown) in which a semiconductor laser and a photodetector are incorporated to constitute an optical head. I do.
[0013]
The lens holder 2 is provided with an optical path hole 4 for securing an optical path of the objective lens 3 at a portion where the objective lens 3 is attached. The lens holder 2 includes a focusing coil 5 wound around the entire side surface of the lens holder 2 and tracking coils 6 wound on both sides of two effective sides of the lens holder 2, respectively. Be placed.
[0014]
Positioning members 7 and 8 are integrally formed on the frame 1 so as to protrude inward from both side walls facing the both sides of the lens holder 2 respectively. Are formed with projections 7a and 8a to be inserted into the optical path holes 4 of the lens holder 2, respectively.
[0015]
The positioning members 7, 8 are provided with ribs 7b, 8b for supporting the lens holder 2 in abutment, respectively. The ribs 7b, 8b are installed in the direction of the optical axis of the objective lens 3 of the lens holder 2. Used to set position.
[0016]
Next, a method of assembling the objective lens driving device including such components will be described.
[0017]
First, the driving coils of the focusing coil 5 and the tracking coil 6 wound using an automatic machine are mounted on the lens holder 2, and the lens holder 2 is positioned in the light path hole 4 from the bottom side of the frame 1. It is installed on the frame 1 so that the projections 7a, 8a of the members 7, 8 are inserted.
[0018]
In this case, since the positioning members 7 and 8 are provided separately and elasticity is imparted to the positioning members 7 and 8, the lens holder 2 is easily and firmly engaged with the positioning members 7 and 8. You.
[0019]
When the lens holder 2 is installed on the frame 1, as shown in the cross-sectional view of FIG. 5, the claw at the tip of each of the projections 7a and 8a is engaged with the edge of the optical path hole 4, whereby the lens holder 2 The installation position of the objective lens 3 in the direction orthogonal to the optical axis is set, and the ribs 7b, 8b of the positioning members 7, 8 are brought into contact with the upper surface of the lens holder 2 on which the objective lens 3 is mounted. Thus, the installation position of the lens holder 2 in the optical axis direction of the objective lens 3 is set.
[0020]
Since the lens holder 2 is set at a predetermined position on the frame 1 in this manner, each suspension wire 10 is connected to the frame 1 to support the lens holder 2 so as to be displaceable in the focus direction and the tracking direction with respect to the frame 1 in this state. And the lens holder 2.
[0021]
When each suspension wire 10 is installed, a wiring board 11 for fixing the end of each suspension wire 10 by soldering is screwed to a predetermined end surface of the frame 1, and each hole into which each suspension wire 10 is inserted is inserted. Each of the suspension wires 10 is inserted through each of the holes 11a of the wiring board 11 using a jig (not shown) in which the lens holder 11a has a funnel shape. Are inserted through holes 12a formed in the respective support portions 12 protruding from the upper and lower sides of the center of predetermined two opposite side surfaces. After each suspension wire 10 is installed in the suspension wire insertion space 20, a dump agent is filled.
[0022]
In this case, since the lens holder 2 is installed at a predetermined position of the frame 1, each suspension wire 10 inserted from each hole of the wiring board 11 is smoothly inserted into the hole 12a of each support portion 12, and It is reduced that the wire 10 is distorted and the stress remains in the suspension wire 10.
[0023]
The distal end of each suspension wire 10 is attached to each projection 13 of the lens holder 1 to which a predetermined terminal of each of the driving coils of the focusing coil 5 and the tracking coil 6 is entangled.
[0024]
Each suspension wire 10 is soldered and fixed to the protruding piece 13 at the distal end, and soldered and fixed to the wiring board 11 at the terminal end, and a lens is formed at the hole 12a of each support portion 12 by an ultraviolet curing adhesive. It is adhered to the holder 2.
[0025]
In this way, the lens holder 2 is supported by the frame 1 with each suspension wire 10 being erected.
[0026]
The frame 1 is provided with a magnetic circuit for generating an effective magnetic field in an effective area of each drive coil of the lens holder 2. The magnetic circuit includes a pair of permanent magnets 14 and 15 having the same magnetic pole opposed to each other. Each of the permanent magnets 14 and 15 is provided with a back yoke portion, and each of the permanent magnets 14 and 15 is provided with a respective yoke 16 and 17 having an opposing yoke portion facing a predetermined magnetic pole surface. 17 is fixed to a predetermined position of the frame 1 by an adhesive.
[0027]
With the suspension wires 10 installed in this way and the magnetic circuit formed, the positioning members 7, 8 are cut off from the side walls of the frame 1 and removed, and the lens holders by the positioning members 7, 8 are removed. Release the position restriction of 2.
[0028]
As a result, the lens holder 2 is displaceably supported so that focus control for focusing the light beam on the signal surface of the disk and tracking control for following the light beam on the signal track of the disk can be performed.
[0029]
Here, grooves 18 and 19 are formed on the upper surface side of the root portions of the positioning members 7 and 8, respectively, so that the positioning members 7 and 8 are easily broken off by the grooves 18 and 19. I have. Therefore, the positioning members 7 and 8 are easily and reliably removed from the root portion, and the displacement of the lens holder 2 is not hindered by the positioning members 7 and 8.
[0030]
After the positioning members 7 and 8 are removed, the objective lens 3 is fixed at a predetermined position on the optical path hole 4 of the lens holder 2 with an adhesive.
[0031]
In this way, as shown in FIG. 4, the assembly of the objective lens driving device is completed. In this state, the lens holder 2 is displaceably supported by the frame 1 and the effective area of each drive coil is within the effective magnetic field. By supplying a focus control signal to the focusing coil 5, the objective lens 3 can be driven in the focusing direction via the lens holder 2 in accordance with the focus control signal. By supplying the tracking control signal, the objective lens 3 can be driven in the tracking direction via the lens holder 2 according to the tracking control signal.
[0032]
By the way, the position of the lens holder 2 is regulated by the positioning members 7 and 8 integrally formed on the frame 1, and the positions of the positioning members 7 and 8 are set according to the dimensional accuracy for forming the frame 1.
[0033]
Therefore, the installation position of the lens holder 2 is set at a predetermined position with respect to the frame 1, and as a result, it is advantageous to install each suspension wire 10 without leaving any stress, and the positional accuracy of disposing the lens holder 2 is improved. And the optical axis shift of the objective lens 3 is less likely to occur when the positioning of the positioning members 7 and 8 with respect to the lens holder 2 is released.
[0034]
【The invention's effect】
As described above, according to the present invention, since the position of the lens holder is regulated by the positioning member integrally formed on the frame and the lens holder is arranged on the frame, an assembly jig for installing the lens holder is not used. The lens holder can be placed at a predetermined position on the frame, and the workability is good, and the lens holder can be realized with the dimensions of the part that integrally molds the frame regardless of the dimensional accuracy and installation variation of the assembly jig. Of the mounting position can be improved.
[0035]
In particular, the positioning members are provided so as to protrude inward from both side walls of the lens holder, and the respective projections formed on the respective positioning members are inserted into the optical path holes of the lens holder, and the edge portions of the optical path holes. It is not necessary to change the shape of the lens holder in order to engage with each positioning member, and the elasticity is imparted to each positioning member, so that the lens holder can be easily and firmly fixed. Can be engaged.
[0036]
Further, since the positioning member is provided with a rib for supporting the lens holder in order to set the installation position of the lens holder in the optical axis direction, the setting position of the lens holder in the optical axis direction of the objective lens is set. Can also be done.
[Brief description of the drawings]
FIG. 1 is a developed perspective view showing a developed state of a main part of an objective lens driving device according to the present invention from a bottom surface side.
FIG. 2 is a perspective view showing an assembled state of the objective lens driving device shown in FIG. 1 from a bottom surface side.
FIG. 3 is a perspective view showing an assembled state of the objective lens driving device shown in FIG. 1 from a top surface side.
FIG. 4 is a perspective view showing a completed state of the objective lens driving device shown in FIG. 1 from a top surface side.
FIG. 5 is a cross-sectional view showing a state where the lens holder 2 is installed on the frame 1.
[Explanation of symbols]
Reference Signs List 1 Frame 2 Lens holder 3 Objective lens 4 Optical path hole 7, 8 Positioning member 7a, 8a Projection 7b, 8b Rib 10 Suspension wire

Claims (3)

An objective lens driving device that supports a lens holder on which an objective lens is mounted so as to be displaceable with respect to a frame, comprising a positioning member having a projection inserted into an optical path hole for securing an optical path of the objective lens of the lens holder. The lens holder is formed integrally with the frame, and the projection is inserted into the hole for the optical path of the lens holder to position the lens holder with respect to the frame. An objective lens, wherein a suspension member is mounted on a frame and a lens holder so as to be displaceably supported with respect to the lens holder, and the positioning member is removed from the lens holder while the lens holder is supported on the frame by the suspension member. Drive. The positioning members are provided so as to protrude inward from both side walls facing each other on both side surfaces of the lens holder, and each projection formed on each positioning member is inserted into a hole for an optical path of the lens holder, and the optical path is formed. 3. The objective lens driving device according to claim 1, wherein the objective lens driving device is engaged with an edge of the hole. 3. The objective lens driving device according to claim 1, wherein a rib for supporting the lens holder is provided on the positioning member to set an installation position of the lens holder in the optical axis direction of the objective lens. .

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