JP2009099214A - Optical head device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical head device improving stiffness at a folded part without increasing the thickness of the folded part as compared with before. <P>SOLUTION: The optical head device has a lens holder for holding an objective lens and a drive coil, and a yoke for holding a drive magnet 71 for composing a magnetic circuit for drive along with the drive coil. The yoke has the folded part 61d that is formed by folding a flat magnetic body and has a drive magnet 71. The folded part 61d is formed wider than the drive magnet 71, has the drive magnet 71 deviated from the center position in a width direction, and has projections 61a, 61b for preventing the drive magnet 71 from moving to the center position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical head device used for reproducing or recording an optical recording disk such as a CD (Compact Disk) or a DVD (Digital Versatile Disk).

As a conventional optical head device, a thin optical head device is known (for example, see Patent Document 1). A conventional optical head device includes a lens holder that holds an objective lens and a drive coil, and a yoke that holds a drive magnet that constitutes a drive magnetic circuit together with the drive coil. The yoke has a bent portion formed by bending a flat magnetic body and provided with a drive magnet.
JP 2007-188564 A

  However, in the conventional optical head device, the width of the bent portion is formed to be approximately the same as the width of the drive magnet in a situation where the drive magnet is downsized with the miniaturization of the optical head device. There is a problem that the bent portion resonates due to insufficient rigidity.

  As a method of improving the rigidity of the bent portion, there is a method of increasing the thickness of the bent portion, but if the bent portion is thick, there is a problem that the bent portion is liable to be cracked when the bent portion is bent. In addition, there is a problem that the bulge of the magnetic material that can be formed on the valley fold side of the bent portion or on the outer side in the width direction is large, and the drive magnet and other members cannot be disposed in the vicinity of the bent portion.

  The present invention has been made in order to solve the conventional problems, and an object of the present invention is to provide an optical head device capable of improving the rigidity of the bent portion without increasing the thickness of the bent portion. And

  An optical head device of the present invention includes a lens holder that holds an objective lens and a drive coil, and a yoke that holds a drive magnet that constitutes a drive magnetic circuit together with the drive coil. A bent portion formed by bending the body and provided with the drive magnet, and the bent portion is formed to have a width larger than the width of the drive magnet and from a central position in the width direction. The drive magnet is biased and has a blocking portion for blocking the drive magnet from moving to the center position.

  With this configuration, the optical head device of the present invention has the disadvantage that the width of the bent portion is larger than the width of the drive magnet, that is, the drive magnet is attracted to the central position of the bent portion that is a magnetic body. Since it can be eliminated by the blocking portion, the rigidity of the bent portion can be improved compared to the conventional one without increasing the thickness of the bent portion by making the width of the bent portion larger than the width of the drive magnet. .

  The optical head device of the present invention includes a lens holder that holds an objective lens and a drive coil, and a yoke that holds a drive magnet that constitutes a drive magnetic circuit together with the drive coil. A plurality of bent portions each formed by bending the magnetic material and provided with the drive magnets; and a connecting portion that connects the plurality of bent portions; It has a blocking part for blocking the drive magnet from moving in the direction of the connecting part.

  With this configuration, the optical head device of the present invention eliminates the inconvenience caused by connecting a plurality of bent portions by the connecting portion, that is, the inconvenience that the drive magnet is attracted in the direction of the connecting portion that is a magnetic body, by the blocking portion. Therefore, by connecting the plurality of bent portions with the connecting portion, the rigidity of the bent portion can be improved more than before without increasing the thickness of the bent portion.

  The drive magnet of the optical head device according to the present invention is preferably characterized in that the drive magnet is bonded and fixed to the bent portion with a screw lock adhesive, an epoxy adhesive, or an anaerobic adhesive.

  In the optical head device of the present invention, since the movement of the drive magnet can be blocked by the blocking portion, the drive magnet and the bent portion are adhesives other than the quick-drying adhesive, that is, screw lock adhesive, epoxy type It can be adhered by an adhesive or an anaerobic adhesive.

  ADVANTAGE OF THE INVENTION According to this invention, the optical head apparatus which can improve the rigidity of a bending part conventionally can be provided, without increasing the thickness of a bending part conventionally.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  First, the configuration of the optical head device according to the present embodiment will be described.

  FIG. 1 is a perspective view of an optical head device 10 according to the present embodiment. FIG. 2 is an exploded perspective view of the optical head device 10. FIG. 3 is a perspective view of the optical head device 10 with some components removed.

  The optical head apparatus 10 shown in FIG. 1 reproduces information on an optical recording disk (not shown) such as a CD disk or a DVD disk by using a laser beam having a wavelength of 650 nm and a laser beam having a wavelength of 780 nm. And a two-wavelength optical head device capable of recording.

  As shown in FIGS. 1 to 3, the optical head device 10 includes a metal device frame 11 made of a die-cast product such as magnesium or zinc, and the device frame 11 disposed on the optical recording disk side with respect to the device frame 11. A laser light source device 21 as a laser light source including a metal cover 12 and a metal cover 13 covering the various components above, an AlGaInP-based semiconductor laser emitting a laser beam having a wavelength of 650 nm, and a laser having a wavelength of 780 nm A laser light source device 22 including an AlGaAs semiconductor laser that emits light, a laser light source device 21, a monitor light receiving element 23 for receiving laser light emitted by the laser light source device 22, and recording on an optical recording disk A signal detecting light receiving element 24 for receiving the laser light reflected by the surface, and a laser light source device 21; And an optical system 30 including an objective lens 31 for converging the laser light emitted by the laser light source device 22 on the recording surface of the optical recording disk, and an objective mounted on the apparatus frame 11 for servo-controlling the position of the objective lens 31. The lens driving mechanism 40 includes a laser light source device 21, a laser light source device 22, a monitor light receiving element 23, a signal detecting light receiving element 24, and a flexible circuit board 50 electrically connected to the objective lens driving mechanism 40. Yes.

  The apparatus frame 11 includes a bearing 11a and a bearing 11b that engage with a guide shaft and a feed screw shaft (not shown) for driving an optical recording disk, a positioning projection 11c for the metal cover 12, and a metal cover 12. And a claw 11d for fastening the head.

  The metal cover 12 includes a hole 12 a that fits into the protrusion 11 c of the device frame 11 and a groove 12 b that engages with the claw 11 d of the device frame 11.

  The metal cover 13 has a hole 13 a through which the laser light emitted from the objective lens 31 passes and covers the objective lens driving mechanism 40.

  The laser light source device 21, the laser light source device 22, and the monitor light receiving element 23 are mounted on the device frame 11 and covered with a metal cover 12.

  The optical system 30 transmits the laser light emitted from the laser light source device 21 and reflects the laser light emitted from the laser light source device 22, and an optical path combining polarizing prism 32, and between the laser light source device 21 and the polarizing prism 32. , A diffractive element 33 in which a half-wave plate is integrally formed, a diffractive element 34 and a relay lens 35 disposed between the laser light source device 22 and the polarizing prism 32, a monitor light receiving element 23 and a polarized light A half mirror 36 disposed between the prisms 32 to partially reflect the laser light emitted from the polarizing prism 32 and a phase difference of ¼ wavelength to the laser light emitted from the polarizing prism 32 and reflected by the half mirror 36. A quarter-wave plate 37 for generating a laser beam, and a collimating lens 38 for converting the laser light transmitted through the quarter-wave plate 37 into parallel light, And a raising mirror 39 to launch toward the optical recording disc, laser light which is collimated by Li formate lens 38.

  The polarizing prism 32, the diffractive element 33, the diffractive element 34, the relay lens 35, the half mirror 36, the quarter wavelength plate 37, the collimating lens 38, and the rising mirror 39 are mounted on the apparatus frame 11. The polarizing prism 32, the diffraction element 33, the diffraction element 34, the relay lens 35, the half mirror 36, and the quarter wavelength plate 37 are covered with the metal cover 12. The collimating lens 38 and the raising mirror 39 are covered with an objective lens driving mechanism 40.

  The flexible circuit board 50 is electrically connected to an end portion (not shown) electrically connected to the laser light source device 21, an end portion 50 b electrically connected to the laser light source device 22, and the monitor light receiving element 23. An end portion 50c to be connected, an end portion 50d electrically connected to the signal detection light-receiving element 24, and an end portion (not shown) electrically connected to the objective lens driving mechanism 40; It is partially bent and mounted three-dimensionally on the apparatus frame 11 and covered with a metal cover 12.

  FIG. 4 is a perspective view of the objective lens driving mechanism 40. 5A and 5B are a plan view and a right side view of the objective lens driving mechanism 40, respectively. 6A to 6C are a front view, a rear view, and a bottom view of the objective lens driving mechanism 40, respectively. In FIG. 4 and FIG. 6A, illustration of a gel-like cushioning material to be described later is omitted.

  As shown in FIG. 4 to FIG. 6, the objective lens driving mechanism 40 is substantially symmetric in the tracking direction indicated by the arrow Tr, and thus description of one side is omitted. The objective lens drive mechanism 40 includes a magnetic yoke 60 fixed to the apparatus frame 11 (see FIG. 2), drive magnets 71 and 72 attached to the yoke 60, and a lens holder 80 that holds the objective lens 31. The tracking drive coils 91 and 92 that constitute a magnetic circuit for driving in the tracking direction indicated by the arrow Tr together with the drive magnets 71 and 72 attached to the lens holder 80 and the drive magnets 71 and 72 attached to the lens holder 80 A focusing drive coil 93 constituting a magnetic circuit for driving in the focusing direction indicated by an arrow Fo, wires 101 to 103 connected to the lens holder 80, and the lens holder 80 fixed to the yoke 60 via the wires 101 to 103. Tracking direction indicated by arrow Tr, A holder support member 110 that is movably supported in a focusing direction indicated by a mark Fo and a tilt direction indicated by an arrow Ti, an end portion (not shown) of the flexible circuit board 50 (see FIG. 2), and wires 101 to 103 are electrically connected And a substrate 120 fixed to the holder support member 110 and a screw 130 for fixing the lens holder 80 and the substrate 120 to the yoke 60.

  FIG. 7A is a plan view of the yoke 60, the holder support member 110, and the substrate 120. FIG. 7B is a right side view of the yoke 60, the holder support member 110, and the substrate 120. 8A and 8B are a cross-sectional view taken along the line AA and a cross-sectional view taken along the line BB in FIG. 7A, respectively. In FIG. 8B, illustration of a gel-like cushioning material to be described later is omitted.

  As shown in FIGS. 7 and 8, the yoke 60 includes a wall portion 61 to which the drive magnet 71 is fixed, a wall portion 62 that is arranged in parallel with the wall portion 61 and to which the drive magnet 72 is fixed, and a wall portion 61. And the wall part 62 is connected, the installation part 63 installed in the apparatus frame 11 (refer FIG. 2), and it is raised from the installation part 63, and is inserted in the focusing drive coil 93 (refer FIG. 5A). An insertion portion 64, a wall portion 65 arranged in parallel to the wall portion 62 on the opposite side of the wall portion 61 with respect to the wall portion 62, and the wall portion 62 and the wall portion 65 are connected to the wall portion 62. And a support portion 66 that supports the wall portion 65.

  The wall 61 includes cylindrical projections 61a and 61b used for positioning in the tracking direction indicated by an arrow Tr (see FIG. 5A) of the drive magnet 71, and an arrow Fo (FIG. 5B of the drive magnet 71). ) See). A cylindrical projection 61c used for positioning in the focusing direction shown in FIG. 5), a bent portion 61d formed by bending a flat magnetic body and provided with a drive magnet 71, and an arrow Tr And a connecting portion 61e that connects two bent portions 61d separated in the tracking direction shown. Since the collimating lens 38 (see FIG. 2) is inserted between the two bent portions 61d separated in the tracking direction indicated by the arrow Tr, the connecting portion 61e is provided with an arrow for reducing the thickness of the optical head device 10. The width in the focusing direction indicated by Fo is small. Therefore, the bent portion 61d has a larger width in the tracking direction indicated by the arrow Tr in order to ensure rigidity, and is formed larger than the width of the drive magnet 71 in the tracking direction indicated by the arrow Tr. Further, the bending magnet 61d is provided with a drive magnet 71 that is biased to one side from the center position in the width direction in the tracking direction indicated by the arrow Tr, that is, toward the connecting portion 61e. The protrusions 61a and 61b formed on the bent portion 61d are located at the center position in the width direction of the bent portion 61d in the tracking direction indicated by the arrow Tr with respect to the center position in the width direction of the drive magnet 71 in the tracking direction indicated by the arrow Tr. And constitutes a blocking portion that prevents the drive magnet 71 from moving to the center position in the width direction of the bending portion 61d in the tracking direction indicated by the arrow Tr.

  The wall portion 62 includes cylindrical protrusions 62a and 62b used for positioning in the tracking direction indicated by the arrow Tr of the drive magnet 72, and cylindrical protrusions used for positioning in the focusing direction indicated by the arrow Fo of the drive magnet 72. 62c, a connecting portion 62e that connects the bent portion 62d formed by bending the flat magnetic body and provided with the drive magnet 72, and the two bent portions 62d separated in the tracking direction indicated by the arrow Tr. And have. The protrusions 62a and 62b formed on the bent portion 62d are installed in the direction of the connecting portion 62e with respect to the center position in the width direction of the driving magnet 72, and the driving magnet 72 moves in the direction of the connecting portion 62e. The blocking part which blocks

  The wall portion 65 has a screw hole 65a into which the screw 130 is screwed, and a hole 65b (see FIG. 4) that is opened on both sides of the screw hole 65a and used for positioning the holder support member 110. .

  The drive magnets 71 and 72 have an N pole on the insertion portion 64 side of the yoke 60. In other words, when the objective lens 31 side of the drive magnets 71 and 72 is the inside, the outside is the N pole. The drive magnets 71 and 72 are adhesively fixed to the bent portions 61d and 62d of the yoke 60 with a screw lock adhesive, an epoxy adhesive, or an anaerobic adhesive, respectively.

  As shown in FIGS. 4 to 6, the tracking drive coil 91 is disposed between the drive magnet 71 and the insertion portion 64 of the yoke 60, one of the two sides extending in the focusing direction indicated by the arrow Fo. ing. Here, a magnetic field is generated between the drive magnet 71 and the insertion portion 64 of the yoke 60 in the direction indicated by the arrow 10a perpendicular to both the focusing direction indicated by the arrow Fo and the tracking direction indicated by the arrow Tr. ing. Therefore, the tracking drive coil 91 receives the electromagnetic force in the tracking direction indicated by the arrow Tr when the current is passed, and moves the objective lens 31 fixed to the lens holder 80 in the tracking direction indicated by the arrow Tr. Although the positional relationship between the tracking drive coil 91 and the drive magnet 71 and the insertion portion 64 of the yoke 60 has been described, the positional relationship between the tracking drive coil 92 and the drive magnet 72 and the insertion portion 64 of the yoke 60 is the same. . The tracking drive coils 91 and 92 are wired only in the tracking direction indicated by the arrow Tr by the objective lens 31 due to the electromagnetic force generated in the tracking drive coils 91 and 92 when a current is passed through the tracking drive coils 91 and 92. Properly set to move.

  The focusing drive coil 93 has one side of the two sides extending in the tracking direction indicated by the arrow Tr disposed between the drive magnet 71 and the insertion portion 64 of the yoke 60, and the other side connected to the drive magnet 72. The yoke 60 is disposed between the insertion portion 64 and the insertion portion 64. Here, a magnetic field is generated between the drive magnet 71 and the insertion portion 64 of the yoke 60 and between the drive magnet 72 and the insertion portion 64 of the yoke 60 in the direction indicated by the arrow 10a and opposite to each other. Yes. Accordingly, the focusing drive coil 93 receives an electromagnetic force in the focusing direction indicated by the arrow Fo when an electric current flows, and moves the objective lens 31 fixed to the lens holder 80 in the focusing direction indicated by the arrow Fo. Note that the objective lens 31 is controlled by the arrows by controlling the currents flowing in the focusing drive coils 93 so that electromagnetic forces in the focusing directions indicated by the arrows Fo in the two focusing drive coils 93 and in opposite directions are generated. It can move in the tilt direction indicated by Ti.

  The wires 101 to 103 are wires having a predetermined spring constant and extend in the direction indicated by the arrow 10a, respectively, along the focusing direction indicated by the arrow Fo on both sides of the lens holder 80 in the tracking direction indicated by the arrow Tr. Arranged. The wires 101 to 103 are electrically connected to any of the tracking drive coils 91 and 92 and the focusing drive coil 93 via the substrate 81 on the lens holder 80 at the end on the lens holder 80 side, respectively. It is electrically connected to the substrate 120 at the end on the side.

  The holder support member 110 includes a center hole (not shown) formed in the center and through which the screw 130 is passed, a protrusion 111 formed on both sides of the center hole and inserted into the hole 65b of the yoke 60 for positioning, and a center hole The projections 112 formed on both sides of the substrate 120 and used for positioning of the substrate 120 are formed on the opposite side of the center hole with respect to the projection 111 and opened to the lens holder 80 side, and the wires 101 to 103 are inserted. It has a gel pot 113 and holes 114, 115, 116 that communicate with the gel pot 113 and open to the substrate 120 side and into which wires 101, 102, 103 are inserted, respectively.

  FIG. 9 is a cross-sectional view taken along the line CC in FIG.

  As shown in FIG. 9, a gel-like cushioning material 117 in which the wires 101 to 103 are embedded is enclosed in the gel pot 113 of the holder support member 110. The gel buffer material 117 suppresses a resonance phenomenon that tends to occur in the lens holder 80 fixed to the wires 101 to 103 when the wires 101 to 103 are embedded.

  As shown in FIGS. 4 to 6, the substrate 120 is formed in the center and has a center hole (not shown) through which the screw 130 passes, and the protrusions 112 of the holder support member 110 formed on both sides of the center hole for positioning. Are inserted into the hole 121 and through holes 122 to 124 into which the wires 101 to 103 are inserted.

  As described above, the optical head device 10 has the disadvantage caused by making the width of the bent portion 61d in the tracking direction indicated by the arrow Tr larger than the width of the driving magnet 71 in the tracking direction indicated by the arrow Tr, that is, the drive magnet. Since the protrusions 61a and 61b can eliminate the inconvenience that 71 is attracted to the center position in the width direction of the tracking direction indicated by the arrow Tr of the bent portion 61d that is a magnetic body, the bending in the tracking direction indicated by the arrow Tr By making the width of the portion 61d larger than the width of the drive magnet in the tracking direction indicated by the arrow Tr, the rigidity of the bent portion 61d can be improved compared to the conventional one without increasing the thickness of the bent portion 61d. As shown in FIG. 8A, when the drive magnet 71 partially protrudes from the bent portion 61d, the drive magnet 71 tends to move in a direction that does not protrude from the bent portion 61d. , 61b are particularly effective for preventing the drive magnet 71 from moving.

  Further, the optical head device 10 has a disadvantage caused by connecting the two bent portions 62d separated in the tracking direction indicated by the arrow Tr by the connecting portion 62e, that is, in the direction of the connecting portion 62e in which the drive magnet 72 is a magnetic body. Since the inconvenience of being pulled can be eliminated by the protrusions 62a and 62b, the two bent portions 62d are connected by the connecting portion 62e, so that the thickness of the bent portion 62d is not increased compared to the conventional case. Rigidity can be improved as compared with the prior art.

  Further, the optical head device 10 can prevent the movement of the drive magnet 71 by the protrusions 61a and 61b, and can prevent the movement of the drive magnet 72 by the protrusions 62a and 62b. The portion 61d, the drive magnet 72, and the bent portion 62d can be bonded to each other by an adhesive other than a quick-drying adhesive, that is, a screw lock adhesive, an epoxy adhesive, or an anaerobic adhesive. Therefore, the optical head device 10 does not need to bond the drive magnet 71 and the bent portion 61d and the drive magnet 72 and the bent portion 62d with the quick-drying ultraviolet curable resin as in the prior art. Equipment for curing can be dispensed with.

1 is a perspective view of an optical head device according to an embodiment of the present invention. It is a disassembled perspective view of the optical head apparatus shown in FIG. FIG. 2 is a perspective view of the optical head device shown in FIG. 1 with some components removed. FIG. 2 is a perspective view of the objective lens driving mechanism shown in FIG. 1, in which the gel-like cushioning material is not shown. (A) It is a top view of the objective lens drive mechanism shown in FIG. (B) It is a right view of the objective lens drive mechanism shown in FIG. (A) It is a front view of the objective-lens drive mechanism shown in FIG. 1, Comprising: It is the figure which abbreviate | omitted illustration of the gel-like buffer material. (B) It is a rear view of the objective lens drive mechanism shown in FIG. (C) It is a bottom view of the objective lens drive mechanism shown in FIG. (A) It is a top view of the yoke shown in FIG. 2, a holder support member, and a board | substrate. (B) It is a right view of the yoke shown in FIG. 2, a holder support member, and a board | substrate. (A) It is AA arrow sectional drawing of Fig.7 (a). (B) It is BB arrow sectional drawing of Fig.7 (a), Comprising: It is the figure which abbreviate | omitted illustration of the gel-like buffer material. It is CC sectional view taken on the line of FIG.6 (b).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical head apparatus 31 Objective lens 60 Yoke 61a, 61b Protrusion (blocking part)
61d bent part 62a, 62b protrusion (blocking part)
62d Bending part 62e Connecting part 71, 72 Drive magnet 80 Lens holder 91, 92 Tracking drive coil 93 Focusing drive coil

Claims (3)

A lens holder that holds an objective lens and a drive coil, and a yoke that holds a drive magnet that constitutes a drive magnetic circuit together with the drive coil;
The yoke has a bent portion formed by bending a flat magnetic body and provided with the drive magnet;
The bent portion is formed to have a width larger than the width of the drive magnet, and the drive magnet is disposed offset from a center position in the width direction, and the drive magnet is prevented from moving to the center position. An optical head device comprising a blocking portion. A lens holder that holds an objective lens and a drive coil, and a yoke that holds a drive magnet that constitutes a drive magnetic circuit together with the drive coil;
The yoke includes a plurality of bent portions formed by bending a flat magnetic body and provided with the drive magnets, and a connecting portion that connects the plurality of bent portions,
The optical head device according to claim 1, wherein the bent portion includes a blocking portion that blocks the drive magnet from moving in the direction of the connecting portion. 3. The optical head device according to claim 1, wherein the drive magnet is bonded and fixed to the bent portion with a screw lock adhesive, an epoxy adhesive, or an anaerobic adhesive.

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