JP2005166222A - Optical pickup device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device and its manufacturing method which can simplify its coil attachment structure and reduce magnetic losses. <P>SOLUTION: This optical pickup device has a holder (lens holder 8) to hold the objective lens (10), a focusing coil (22), and tracking coils (34-40) attached to this holder. The holder is a resin mold, and the focusing coil is buried in the resin mold. The tracking coils are attached to the mounting sections (projections 42) formed on the holder. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to an optical pickup device used for irradiating an optical disk with a light beam and receiving a reflected light beam thereof, and more particularly to an optical pickup device in which a structure for attaching various coils to a lens holder is simplified and a manufacturing method thereof.

  The optical pickup device supports a lens holder that holds an objective lens so that the lens holder can be displaced on a support shaft, and the lens holder includes a focus coil and a tracking coil, and controls the irradiation direction of the light beam from the light source to the optical disk. A mechanism and a tracking mechanism are provided. The lens holder is caused to act by applying a static magnetic field adjacent to the lens holder, and generating a magnetic field by giving independent drive signals to the focus coil and the tracking coil. Is adjusted in the vertical direction, or tracking adjustment is performed in the horizontal direction.

For example, the following patent documents exist in the technology relating to such an optical pickup device.
JP-A-9-147388 JP 2003-196862 A Japanese Patent Laid-Open No. 9-212888

  In Patent Document 1, a fixed-side holder and a movable-side holder are provided, and an objective lens is attached to the movable-side holder, and a beam member is disposed between the fixed-side holder and the movable-side holder. A structure attached by insert molding of a holder is disclosed. In this optical pickup device, the attitude control drive coil is attached to the movable side holder.

  Further, in Patent Document 2, a cylindrical portion in which a shaft hole through which a support shaft is inserted is formed in a substantially central portion of the lens holder, and a focus coil and a plurality of tracking coils are formed on the outer peripheral portion of the cylindrical portion. It is attached so as to be orthogonal. The cylindrical portion, the focus coil, and the tracking coil are configured as separate members, and each tracking coil has a structure in which the winding center is attached in a direction orthogonal to the central axis of the shaft hole.

  Patent Document 3 discloses an optical pickup in which a coil support plate is attached to a coil bobbin of a focus coil, and a coil is wound around a coil bobbin portion formed on each coil support plate.

  By the way, in such an optical pickup device, the structure made up of the lens holder and various coils is a fine structure, and the configuration for adjusting the objective lens in a desired direction affects the pickup performance due to the installation accuracy of the coil with respect to the lens holder. It will be. The lens holder is a molded body made of synthetic resin, in which a focus coil is arranged on the inner part, a plurality of tracking coils having an inner diameter of 1 mm or less are arranged on the outer part, and these are fixed with an adhesive. However, it is difficult to control the adhesive application position and its quantification, and a highly precise arrangement position between the focus coil and the tracking coil is required, so the adhesive between the lens holder and the focus coil, and the focus coil and the tracking coil. It has been pointed out that there are inconveniences such as a decrease in yield and poor working efficiency. Further, the configuration in which the coil support plate is installed on the coil bobbin of the focus coil or the coil is wound around the coil bobbin formed on the coil support plate has the disadvantage that the number of parts is large, the structure is complicated, and the workability is poor. is there.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical pickup device that realizes a reduction in magnetic loss as well as a simplified structure for fixing a coil, and a method for manufacturing the same.

  In order to achieve the above object, an optical pickup device of the present invention includes a holder (lens holder 8) for holding an objective lens (10), a focus coil (22) and tracking coils (34 to 40) attached to the holder. The holder is a resin molded body, the focus coil is embedded and fixed in the resin molded body, and the tracking coil is attached to a mounting portion (projection 42) formed in the holder. It is the structure which is attached.

  In this optical pickup device, air-core coils are used for the focus coil and tracking coil. Therefore, by embedding and fixing the focus coil in a holder as a resin molded body, the focus coil is integrated with the holder and configured as a single component. A mounting portion is formed on the holder, and a tracking coil is attached to the mounting portion.

  In order to achieve the above object, the mounting portion may be a protrusion (42) formed on the holder and inserted into the tracking coil, or a recess into which the tracking coil is fitted. As described above, the tracking coil is an air-core coil. For example, when an air-core coil is formed by winding a copper wire coated with an insulating coating on the surface of the core, the inner diameter of the coil is maintained with high accuracy. The Therefore, if the mounting portion is constituted by a protrusion, the tracking coil is positioned with high accuracy by the protrusion. Also, even when the tracking coil is formed with a recess that can be inserted, the wire diameter of the coil is constant, and depending on the winding mode, the outer diameter can also be formed with high accuracy. The tracking coil can be positioned with high accuracy.

  In order to achieve the above object, a method for manufacturing an optical pickup device according to the present invention is a method for manufacturing an optical pickup device including a holder for holding an objective lens, and a focus coil and a tracking coil attached to the holder. Forming the holder into a predetermined shape with a synthetic resin, incorporating the focus coil into the holder by integral molding in the molding, forming the tracking coil mounting portion in the holder, and mounting And a step of attaching the tracking coil to the part.

When the holder is molded with synthetic resin, if the focus coil is positioned and molded with resin, the focus coil can be positioned and fixed in the holder with high accuracy. Further, when forming the holder, it is possible to form a mounting portion of the tracking coil on the holder and position and attach the tracking coil to the mounting portion with high accuracy.

  According to the optical pickup device of the present invention, since the focus coil is integrated and fixed in the resin molding body of the holder, the control of the arrangement position of the focus coil and the tracking coil by the conventional adhesive is complicated. In addition, since the tracking coil is positioned and fixed to the mounting portion integrally formed with the holder, the operation with high positional accuracy and high reliability can be realized.

According to the method of manufacturing an optical pickup of the present invention, the focus coil can be fixed to the holder with high accuracy without using an adhesive, and can be fixed by molding. No optical pickup device can be provided. Further, since the mounting portion is formed on the holder, the tracking coil can be attached by being positioned by this mounting portion, so that the uniformity of the product can be improved and the product accuracy can be improved.

  An embodiment of an optical pickup device and a manufacturing method thereof according to the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view showing an optical pickup device being assembled, FIG. 2 is a plan view of a lens holder of the optical pickup device, and FIG. 3 is a sectional view taken along line III-III in FIG.

  This optical pickup device 2 is provided with a lens holder 8 movably on a spindle 6 erected on a support frame 4, and the lens holder 8 includes a frame portion 12 that holds an objective lens 10, and a main body portion. 14. The frame portion 12 and the main body portion 14 are formed of a resin molded body that is integrally formed of a synthetic resin such as liquid crystal polymer or polyurethane. The frame portion 12 is formed so as to protrude forward from the upper portion of the main body portion 14, and includes an annular standing wall 16 surrounding the periphery of the objective lens 10, and a circular window centered on the optical axis of the objective lens 10. A portion 18 is formed. The objective lens 10 is fitted into a space surrounded by the standing wall 10 and is fixed to the frame portion 12 using an adhesive material (not shown).

  The main body portion 14 is, for example, a rectangular structure, and the main body portion 14 is formed with a shaft hole 20 that penetrates the support shaft 6 at the center thereof, and a focus that is installed surrounding the shaft hole 20. The coil 22 is built in, and a part of the coil 22 is exposed to a plurality of window portions 24 formed around the shaft hole 20. An annular standing wall 26 having a tapered surface on the inside is formed at the opening edge of the shaft hole 20. For the focus coil 22, for example, an air-core coil is used by winding a copper wire having an insulating coating applied on the surface around a winding core. The focus coil 22 is molded in the main body portion 14 by insert molding, and coil ends 28 and 30 of the focus coil 22 are drawn out to the rear side of the main body portion 14. A pair of terminal portions 32 used for connecting the coil ends 28 and 30 and the like are formed at the rear portion of the main body portion 14. Therefore, if the focus coil 22 is excited by applying drive signals from the coil ends 28 and 30, a drive force is generated due to the relationship with the static magnetic field (the Fleming's left-hand rule) by a magnet (not shown), and the main body 14 is supported. It can be moved upward or downward about the axis 6. The moving amount and moving speed depend on the magnetic field generated by the focus coil 22.

  In addition, for example, four sets of tracking coils 34, 36, 38, and 40 are installed on the side surface of the main body 14 in two on each side, and these tracking coils 34 to 40 are mounted at predetermined positions on the main body 14. For example, a plurality of rectangular protrusions 42 are formed as mounting parts to be mounted. Each protrusion 42 may be formed integrally with the main body 14, or a rectangular plate as a separate member may be attached to the main body 14, and its outer shape matches the inner diameter of the tracking coils 34 to 40. It is. For these tracking coils 34 to 40, for example, an air core coil is used by winding a copper wire having an insulating coating applied on its surface around a winding core. Therefore, when such an air-core coil is formed by being wound around a winding frame, the inner diameter thereof is maintained with high accuracy, so that the tracking coils 34 to 40 are formed in the shape and position of the protrusion 42 which is a mounting portion. The mounting accuracy depends, and if the tracking coils 34 to 40 are attached to these protrusions 42 and fixed with an adhesive or the like, the positional accuracy is maintained at a high level. The tracking coils 34 to 40 are connected in series, and when a tracking drive signal is applied to the coil ends 44 and 46, the tracking coils 34 and the tracking coils 36, and the tracking 38 and the tracking 40 are in the same polarity direction. When excited, a driving force is generated by the relationship between the magnetic force and the above-described static magnetic field (Fleming's left-hand rule), and the objective lens 10 can be moved in the left or right direction together with the main body 14 around the support shaft 6. it can. The moving amount and moving speed depend on the magnetic field generated by the tracking coils 34-40.

  Next, molding of the main body portion 14 and the frame portion 12 of the lens holder 8 and fixing of the focus coil 22 according to the embodiment of the optical pickup device and the manufacturing method thereof of the present invention will be described with reference to FIG. FIG. 4 shows an outline of a method for forming the main body 14 and the frame 12 of the lens holder 8 and a method for fixing the focus coil 22.

  For example, a synthetic resin injection molding method is used as the molding method and the fixing method, and the cavity 50 corresponding to the product outer shape of the main body portion 14 and the frame portion 12 is formed in one or a plurality of molding dies 48. In addition, an installation space 52 in which the focus coil 22 is installed is formed. In this embodiment, a coil support portion 54 that supports the focus coil 22 is formed.

  Therefore, the forming die 48 is, for example, a split die, and is an air-core coil wound around the coil support portion 54 in advance if the coil support portion 54 is exposed when the die is separated. If the molding resin 56 is injected into the cavity 50 after the focus coil 22 is installed, the air in the cavity 50 is eliminated, and the main body portion 14 and the frame portion 12 are molded by the injected molding resin 56. The focus coil 22 is fixed in the molded body by insert molding. As a result, as shown in FIG. 3, the main body part 14 and the frame part 12 to which only the focus coil 22 is fixed are obtained. At the time of molding, the focus coil 22 is supported by the coil support portion 54 and thus does not move. A part of the molding resin 56 penetrates into the surface wire rod and is firmly fixed in the main body portion 14. That is, the focus coil 22 is manufactured as a single component integrated with the main body 14.

  In this case, although not shown, if the recesses for forming the plurality of protrusions 42 are formed in the cavity 50 of the mold 48, the main body portion 14 including the protrusions 42 can be formed.

  Next, an embodiment of the optical pickup device and the manufacturing method thereof according to the present invention will be described with reference to FIGS.

  As described above, as shown in FIGS. 1 and 2, each of the protrusions 42 of the molded product including the main body portion 14 and the frame portion 12 including the focus coil 22 is made of an air-core coil wound in advance. The tracking coils 34 to 40 are mounted and fixed with an adhesive. Then, as shown in FIG. 3, the objective lens 10 is mounted on the frame portion 12 and fixed with an adhesive or the like. In this case, a method such as ultrasonic welding may be used.

  As described above, in such an optical pickup device and its manufacturing method, the focus coil 22 is molded and fixed in the main body portion 14 of the lens holder 8 by resin molding, so that fixing with an adhesive is unnecessary. . Without considering the quantification of the adhesive, etc., it is possible to contribute to the homogenization of the product and to improve the yield. Further, since the tracking coils 34 to 40 can be prevented from being impregnated with the adhesive, the magnetic loss on the tracking coils 34 to 40 side can be reduced, and the operation efficiency can be increased.

  In the embodiment, for the mounting of the tracking coils 34 to 40, the protrusion 42 is formed integrally with the main body 14 or the protrusion 42 is formed by fixing another member. 14 may be provided with a single or a plurality of recesses corresponding to the mounting form of the tracking coils 34-40, and the tracking coils 34-40 may be mounted in the recesses.

  In addition, polyurethane or liquid crystal polymer is exemplified as the molding resin 56 of the lens holder 8, but various synthetic resins are selected in view of mechanical strength, light weight, low friction with the metallic support shaft 6, and the like. However, the present invention is not limited to the exemplified materials.

As described above, the most preferable embodiment of the present invention has been described. However, the present invention is not limited to the above description, and is described in the claims or disclosed in the specification. It goes without saying that various modifications and changes can be made by those skilled in the art based on the gist, and such modifications and changes are included in the scope of the present invention.

INDUSTRIAL APPLICATION This invention can implement | achieve the optical pick-up apparatus which reduced the number of parts in the assembly process of an optical pick-up apparatus, and reduced the weight, the uniformity, and the operation performance, and is useful.

1 is an exploded perspective view showing an optical pickup device according to an embodiment of the present invention. It is a top view which shows the lens holder of an optical pick-up apparatus. It is the III-III sectional view taken on the line of FIG. It is a figure which shows the shaping | molding of the main-body part and frame part of a lens holder, and the fixing process of a focus coil.

Explanation of symbols

2 Optical pickup device 8 Lens holder 10 Objective lens 22 Focus coil 34 to 40 Tracking coil 42 Projection (mounting part)

Claims (3)

An optical pickup device comprising a holder for holding an objective lens, and a focus coil and a tracking coil attached to the holder,
The optical pickup apparatus, wherein the holder is a resin molded body, the focus coil is embedded and fixed in the resin molded body, and the tracking coil is attached to a mounting portion formed on the holder.   2. The optical pickup device according to claim 1, wherein the mounting portion is a protrusion formed on the holder and inserted into the tracking coil or a recess into which the tracking coil is fitted. A manufacturing method of an optical pickup device comprising a holder for holding an objective lens, and a focus coil and a tracking coil attached to the holder,
Forming the holder into a predetermined shape with a synthetic resin;
A step of incorporating the focus coil by integral molding in the holder at the time of molding;
Forming a mounting portion of the tracking coil in the holder;
Attaching the tracking coil to the attachment part;
An optical pickup device manufacturing method comprising: