JP2006059450A - Optical pickup wiring structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring structure of an optical pickup capable of effectively preventing the detachment of a tip portion of a flexible wiring board.
In an optical pickup P including a lens holder 30 that holds lens groups L1 and L2 and a plate spring 40 that supports the lens holder 30 so as to be displaceable in the thickness direction of the magneto-optical disk, the lens groups L1 and L2 are arranged. L2 includes a coiled lens 21 that is closest to the magneto-optical disk and has a coil for magnetic recording, and a flexible wiring substrate 50 for passing a current through the coil is connected to the lensed coil 21. In the optical pickup wiring structure, the flexible wiring board 50 includes a flat plate portion 50A extending along the plate spring 40, and a tip portion 50B connected to the coiled lens 21 continuously to the flat plate portion 50A. And an opening 50C is provided between the flat plate portion 50A and the tip portion 50B.
[Selection] Figure 2

Description

  The present invention relates to a wiring structure of an optical pickup used in a so-called near-field recording type magneto-optical head.

  An example of a near-field recording type optical pickup is disclosed in Patent Document 1. The conventional optical pickup disclosed in Patent Document 1 includes a lens group that forms a light spot on a magneto-optical disk and a lens holder that holds these lens groups. The lens group includes a lens with a coil having a coil (magnetic recording coil) for applying a magnetic field to the magneto-optical disk to perform magnetic recording, and the lens with the coil is closest to the magneto-optical disk. Are arranged to be.

  In the conventional optical pickup, a wiring structure as shown in FIG. 5 is adopted as an example. As shown in the figure, the lens holder 300 is provided with a focus coil 310 for displacing the lens holder 300 in the thickness direction (focus direction Fc) of the magneto-optical disk, and a carriage (not shown). ), A magnet 710 is fixed so as to face a part of the focus coil 310. Such a lens holder 300 can be displaced in the focus direction Fc while being supported by the fixing portion 700A of the carriage via the leaf spring 400 by controlling the current of the focus coil 310. On the other hand, a flexible wiring substrate 500 for passing a current through a coil for magnetic recording (not shown) is connected to the side of the lens with coil 210. The flexible wiring board 500 includes a flat plate portion 500A attached to the plate spring 400, and a tip portion 500B connected to the side portion of the coiled lens 210 in a standing posture while continuing to the flat plate portion 500A. Have. Since such a flexible wiring board 500 is integrated with the leaf spring 400 and the lens with coil 210, even if the lens holder 300 is displaced in the focus direction Fc, the flexible wiring board 500 does not deform so much.

JP 2003-162850 A

  However, in the above-described conventional optical pickup wiring structure, the portion between the flat plate portion 500A and the tip portion 500B of the flexible wiring substrate 500 is relatively short, so that the lens holder 300 is displaced in the focus direction Fc. The part is easily pulled. Therefore, in a situation where the lens holder 300 is repeatedly displaced in the focus direction Fc, the tip portion 500B of the flexible wiring board 500 may be detached from the side portion of the coiled lens 210.

  The present invention has been conceived under the circumstances described above, and it is an object of the present invention to provide a wiring structure of an optical pickup that can effectively prevent detachment of the distal end portion of a flexible wiring board. Yes.

  In order to solve the above problems, the present invention takes the following technical means.

  The optical pickup wiring structure provided by the present invention comprises a lens group that forms a light spot on a magneto-optical disk, a lens holder that holds these lens groups, and the lens holder is displaced in the thickness direction of the magneto-optical disk. In an optical pickup including a leaf spring that supports the lens, the lens group includes a lens with a coil that is closest to the magneto-optical disk and has a coil for magnetic recording. A wiring structure of an optical pickup in which a flexible wiring board for passing a current to the coil is connected, the flexible wiring board being continuous with the flat plate portion extending along the plate spring. A front end portion connected to the coiled lens, and a flat plate portion and a front end portion of the flexible wiring board. Between, it is characterized in that the opening is provided.

  As a preferred embodiment, the distal end portion of the flexible wiring board is formed wider than the flat plate portion.

  In another preferred embodiment, the flat plate portion of the flexible wiring board is attached to the leaf spring.

  As another preferred embodiment, a terminal portion of the coil is formed on a side portion of the lens with the coil, and a land of the land is obtained by exposing a tip of a conductive wire to a tip of the flexible wiring board. The terminal portion and the land portion are connected by soldering or wire bonding.

  According to such a configuration, the portion between the flat plate portion and the tip portion of the flexible wiring board has a shape that continues around the opening, so that this portion is longer and more flexible than the conventional one. Easy to bend. As a result, even when the lens holder is displaced in the thickness direction of the magneto-optical disk, tension is not easily applied to the portion between the flat plate portion and the tip portion of the flexible wiring board. Thereby, according to this invention, it can prevent effectively that the front-end | tip part of a flexible wiring board remove | deviates from a lens with a coil.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings. 1 to 4 show an embodiment of an optical pickup according to the present invention.

  As shown in FIG. 1, the optical pickup P of the present embodiment records data on a magneto-optical disk (hereinafter simply referred to as “disk”) 80 by a so-called near-field recording method, or records recorded data. It is for playing. In the optical pickup P using the near-field recording method, a perpendicular magnetic field is applied to the recording layer 88 while forming a laser spot by focusing on the recording layer 88 of the disk 80. Such an optical pickup P includes a first lens L1 and a second lens L2 (lens group) for forming a laser spot, a lens holder 30 that holds the first lens L1 and the second lens L2, and a lens holder 30. A pair of leaf springs 40 (see FIGS. 2 and 3) supported so as to be displaceable in the thickness direction (focus direction) of the disk 80, and a flexible wiring board 50 (see FIGS. 2 and 3) connected to the second lens L2. It is configured with. A transparent protective layer 89 having a thickness of, for example, 50 μm or less is formed on the surface of the disk 80, and the recording layer 88 is covered with this extremely thin protective layer 89.

  As well shown in FIG. 3, the first lens L <b> 1 is fixed to the upper opening 30 </ b> A of the lens holder 30. The second lens L2 is configured by combining a plano-convex lens 20 and a coiled lens 21. The light exit surface of the coiled lens 21 is the surface closest to the disk 80, and a coil 22 for applying a magnetic field to the disk 80 is integrally formed in the vicinity of the light exit surface. A terminal portion 22A of the coil 22 is formed on the side of the coiled lens 21 so as to be exposed. The laser light travels toward the disk 80 through the center of the coil 22. Such a second lens L2 is fixed to the light emitting surface side of the first lens L1 via a lens barrel member 60. Thus, the first and second lenses L1 and L2 are held by the lens holder 30 with a predetermined interval therebetween.

  As well shown in FIG. 1, the lens holder 30 is provided inside the carriage 70 in such a posture that the coiled lens 21 faces the disk 80 side. As shown in FIGS. 1 to 3, focus coils 31 for displacing the lens holder 30 in the focus direction Fc are provided on both sides of the lens holder 30. A magnet 71 is fixed to an appropriate portion of the inner wall of the carriage 70 so as to face the linear portion of the focus coil 31. The lens holder 30 is supported by a fixed portion 70A of the carriage 70 via a pair of leaf springs 40 (see FIGS. 2 and 3). Such a lens holder 30 can be displaced in the focus direction Fc by controlling the current of the focus coil 31. For example, when the rotation of the disk 80 is stopped, the lens holder 30 is at the offset position farthest from the disk 80. At this time, the working distance from the surface of the coiled lens 21 to the surface of the protective layer 89 is about 0.5 mm. On the other hand, during the rotation of the disk 80, in order to make the lens with coil 21 follow the disk 80 that moves slightly in the thickness direction (focus direction), the working distance is kept at a very short constant distance, for example, less than 40 μm. I have to hit it. Therefore, during rotation of the disk 80, the lens holder 30 is displaced with a very small movable width of about ± 0.1 mm in the focus direction Fc. The focus coil 31 is configured such that a current is guided through wiring means (not shown) different from the flexible wiring board 50.

  As shown in FIG. 1, the carriage 70 is movable in the tracking direction Tg by, for example, a driving force of a voice coil motor (not shown). By the movement of the carriage 70, a seek operation for placing the lens holder 30 in the vicinity of the target track is performed. The laser light travels from a fixed optical unit (not shown) including a laser diode and a collimator lens toward the carriage 70, and reaches a rising mirror 72 built in the carriage 70. The laser beam reflected upward by the rising mirror 72 passes through the inside of the lens holder 30 and is incident on the first lens L1 and the second lens L2 in this order, and is thereby focused on the recording layer 88 of the disk 80. A laser spot is formed. The fixed optical unit is also provided with a beam splitter and a photodetector. When the laser light is reflected by the recording layer 88, the reflected light is detected by the photodetector. A control microcomputer (not shown) controls the focus coil 31 based on the focus error signal from the photodetector while the disk 80 is rotating, whereby the lens holder 30 is elastically supported by the leaf spring 40. In this state, it is displaced in the focus direction Fc. Although the leaf spring 40 is not shown in FIG. 1, the leaf spring 40 extends along a direction orthogonal to both the focus direction Fc and the tracking direction Tg (a direction perpendicular to the paper surface). Is provided.

  As shown in FIG. 3, the flexible wiring board 50 is for passing an electric current through the coil 22 of the coiled lens 21. For example, a base material 51 and a cover material 52 made of a polyimide film, and these And a conductive wire 53 formed therebetween. The flexible wiring board 50 includes a flat plate portion 50A attached along the plate spring 40, and a tip portion 50B connected to the side portion of the coiled lens 21 in a posture standing up while continuing to the flat plate portion 50A. Have. An opening 50C is provided in a portion between the flat plate portion 50A and the tip portion 50B of the flexible wiring board 50. Therefore, as shown in FIG. 4, the conductive wire 53 is formed so as to bypass both sides of the opening 50C and continue from the flat plate portion 50A to the tip portion 50B. The tip portion 50B is formed to be wider than the flat plate portion 50A. An L-shaped land portion 53 </ b> A is formed at the tip portion 50 </ b> B by exposing the tip of the conducting wire 53 without providing the cover material 52. In order to form the opening 50C, for example, after forming a flexible wiring board in which the distal end portion 50B is wider than the flat plate portion 50A, a portion between the distal end portion 50B and the flat plate portion 50A is formed so as not to cut the conductive wire 53. You only need to overcome it. If it does in this way, the said flexible wiring board 50 can be manufactured easily. In such a flexible wiring board 50, the front end portion 50B is adhered to the surface on the light incident surface side of the lens 21 with coil and the land portion 22A provided on the side portion of the lens 21 with coil is landed. The portion 53A is joined by the solder 65. 3 is connected to a current control circuit (not shown), and a current is guided from the current control circuit to the coil 22 via the flexible wiring board 50. . The wiring structure of the optical pickup P is constituted by such a flexible wiring board 50.

  Next, the operation of the wiring structure of the optical pickup P will be described.

  The amount of displacement of the lens holder 30 in the focus direction Fc is the largest when the disk 80 starts to rotate or stops, and the maximum amount of displacement is about 0.5 mm. While the disk 80 is rotating, the lens holder 30 is only displaced within a range of about ± 0.1 mm. When the lens holder 30 is displaced in the focus direction Fc, the flexible wiring board 50 moves with the flat plate portion 50A and the tip portion 50B being integrated with the plate spring 40 and the coiled lens 21. Therefore, the flexible wiring board 50 does not deform so much from the flat plate portion 50A to the tip portion 50B.

  However, when the lens holder 30 is repeatedly displaced, the relative positional relationship between the leaf spring 40 and the coiled lens 21 is slightly shifted. If it becomes so, the part between the flat plate part 50A and the front-end | tip part 50B in the flexible wiring board 50 will be in the state pulled a little from the beginning.

  Here, the portion between the flat plate portion 50A and the tip portion 50B is continuous while bypassing the opening 50C, and the width dimensions of the flat plate portion 50A and the tip portion 50B are different. Therefore, the portion between the flat plate portion 50A and the tip portion 50B has a slender shape and is likely to bend easily and flexibly as compared with the conventional one in which the opening is not formed with a uniform width dimension from the flat plate portion to the tip portion. It has become. Accordingly, even when the lens holder 30 is repeatedly displaced in the focus direction Fc, the portion between the flat plate portion 50A and the tip portion 50B is not easily tensioned. Therefore, the tip portion 50B of the flexible wiring board 50 is provided with a coil. It does not fall off the side of the lens 21.

  In addition, the flexible wiring board 50 has a tip portion 50B formed wider than the flat plate portion 50A, and accordingly, a land portion 53A in the tip portion 50B is formed in a relatively large L shape. Therefore, the land portion 53A and the terminal portion 22A are firmly bonded via a sufficient amount of solder 65, and the entire distal end portion 50B of the flexible wiring board 50 has a sufficient adhesion surface and the coiled lens 21. Adhered securely to the side. Also from this, the front end portion 50B of the flexible wiring board 50 does not fall off from the side portion of the coiled lens 21.

  By the way, when the optical pickup P is manufactured, after the second lens L2 is fixed to the lens barrel member 60, the first lens L1 is adjusted to the lens barrel member 60 and the lens while finely adjusting the distance from the second lens L2. Secure to holder 30. At this time, the flexible wiring board 50 is already connected to the coiled lens 21 constituting the second lens L2. Further, as an adhesive for fixing the first lens L1, an ultraviolet curable resin is generally used. That is, the fixing portion of the first lens L1 is irradiated with ultraviolet rays, but the fixing portion of the first lens L1 located on the back side of the flexible wiring board 50 is also externally applied through the opening 50C of the flexible wiring board 50. It can be irradiated with ultraviolet rays. Therefore, the first lens L1 can be reliably fixed to the lens barrel member 60 and the lens holder 30.

  In addition, this invention is not limited to said embodiment.

  You may make it join the land part of a flexible wiring board, and the terminal part of a lens with a coil, for example by wire bonding.

1 is an overall cross-sectional view showing an embodiment of an optical pickup according to the present invention. It is a perspective view which shows the wiring structure of the optical pick-up shown by FIG. It is sectional drawing which follows the III-III line of FIG. It is a top view of the flexible wiring board shown by FIG. It is a perspective view which shows the wiring structure of the conventional optical pick-up.

Explanation of symbols

P optical pickup L1 first lens L2 second lens 21 lens with coil 22 coil (for magnetic recording)
22A terminal portion 30 lens holder 40 leaf spring 50 flexible wiring board 50A flat plate portion 50B tip portion 50C opening 53 conducting wire 53A land portion 60 lens barrel member 65 solder 80 magneto-optical disk

Claims (4)

In an optical pickup comprising a lens group that forms a light spot on a magneto-optical disk, a lens holder that holds these lens groups, and a leaf spring that supports the lens holder so as to be displaceable in the thickness direction of the magneto-optical disk The lens group includes a lens with a coil that is closest to the magneto-optical disk and has a coil for magnetic recording. The coiled lens has a flexible wiring board for passing a current through the coil. The wiring structure of the connected optical pickup,
The flexible wiring board has a flat plate portion extending along the plate spring, and a tip portion connected to the coiled lens continuously from the flat plate portion, and
An optical pickup wiring structure, wherein an opening is provided between a flat plate portion and a tip portion of the flexible wiring board.   The wiring structure of the optical pickup according to claim 1, wherein a distal end portion of the flexible wiring board is formed wider than the flat plate portion.   The optical pickup wiring structure according to claim 1, wherein the flat plate portion of the flexible wiring board is attached to the leaf spring.   A terminal portion of the coil is formed on the side portion of the lens with the coil, and a land portion is formed on the tip portion of the flexible wiring board by exposing the tip of the conducting wire. 4. The optical pickup wiring structure according to claim 1, wherein the portion and the land portion are connected by soldering or wire bonding.

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