JP2007200551A - Lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving device of a disk player that stably operates even at high speed by moving a natural resonance frequency to high frequencies. <P>SOLUTION: The lens driving device 100 of the disk player is provided with: a holder 60 having a top face wall 62 to which an objective lens 48 is fixed and a pair of side face walls 63 connected to both end parts of the top face wall 62 in a tracking direction and mutually separately aligned with an opening provided between the pair of side face walls 63; and a pair of flat plate-shaped printed coils 70 respectively attached to both side faces of both the top face wall 62 and the pair of side face walls 63 so as to close the opening. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens driving device for a disc player, and more particularly to the structure of a movable part.

  As is well known, a lens driving device for a disk player that optically reads or writes information recorded on a disk using a laser beam. Generally, a focus coil and a tracking coil are mounted on a holder to which an objective lens is fixed. And the objective lens is driven while performing focus control and tracking control in accordance with drive signals supplied to the respective drive coils.

  A lens driving device of a disc player for displacing an objective lens generally has a natural resonance frequency in each of a focus control system and a tracking control system. This natural resonance frequency is a physical resonance formed by the size and mass of the holder, for example, and when the lens driving device is driven near the natural resonance frequency, harmful vibrations are given to the objective lens. For example, the current lens driving device has the frequency characteristics shown in FIG. In FIG. 12, the horizontal axis represents frequency, and the vertical axis represents gain and phase. As shown in FIG. 12, in the amplitude characteristic indicated by the dotted line, the gain decreases almost linearly as the frequency increases except at the resonance point in the low frequency region. In addition, the phase characteristic indicated by the solid line changes substantially constant up to around 10 kHz as the frequency increases except at the resonance point.

  However, when the frequency is further increased, there is a natural resonance of the lens driving device described above, and therefore the phase characteristic changes abruptly as shown in FIG. 12 near the natural resonance frequency (for example, 20 kHz), and the phase delay becomes 180 degrees. When it reaches, the control system becomes unstable.

  In view of this, in consideration of the natural resonance frequency of each control system, each higher-order resonance is designed to be outside each servo band. In other words, the band required for actual servo control is designed so as to have an upper limit of 2 kHz to 5 kHz, for example, so that it is not affected by the phase change that occurs in the vicinity of the natural resonance frequency.

  By the way, in recent years, disk players have been increased in speed by rotating the disk at twice or four times the standard speed, and high-speed signal reading or writing is performed by the lens driving device of the disk player. There is a need to make it happen.

  When the signal reading or writing speed is increased, each servo band of each control system becomes wider and needs to be expanded to a higher band. However, as described above, for example, if a natural resonance frequency exists in the vicinity of 20 kHz, it becomes difficult to secure a margin between each servo band and higher-order resonance, which causes a problem that each servo control system becomes unstable. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a lens driving device for a disc player that operates stably even when the natural resonance frequency is moved to a high frequency range and the speed is increased. .

  In order to solve the above problems, a lens driving device for a disc player according to the present invention described in claim 1 is a lens driving device for a disc player, and is connected to an upper surface wall to which an objective lens is fixed and the upper surface wall. And a pair of side walls spaced apart from each other in the tracking direction, a holder provided with an opening between the pair of side walls, and the top wall and the pair of side walls so as to close the opening. And a pair of flat plate-like printed coils attached to both side surfaces.

  According to the present invention, the lens driving device of the disc player can reduce the size and weight of the holder by removing the left and right side plates of the holder that constitutes the movable part, and moves the natural resonance frequency of the movable part to a high range. Can operate stably even at higher speeds.

  The lens drive device for a disc player according to the present invention is a lens drive device for a disc player that supports a holder to which an objective lens and a drive coil are fixed so as to be movable in a focus direction and a tracking direction. The drive coil has a shape and a pair of side walls spaced apart and aligned along the tracking direction from the top wall to which the objective lens is fixed, and a pair of side walls aligned along the jitter direction removed. Is a flat printed coil that is formed by printing on a flat plate and generates a driving force in the focus direction and the tracking direction. The flat printed coil is formed between the pair of side walls in the removed side wall region. Fixed so that the coil surface is parallel to either the tracking direction or the focus direction with respect to the side edge. In the holder with is reinforced by flat printed coils, weight and size of the holder is achieved, it is possible to increase the natural resonance frequency of the lens driving device of the disc player.

  FIG. 1 is an external view of a main part of a lens driving device 100 of a disc player according to a disclosed example of the present invention. 1A is a plan view of the lens driving device 100 of the disc player, and FIG. 1B is a side view of the lens driving device 100 of the disc player. The configuration of the lens driving device 100 of the disc player will be described below with reference to FIG.

  In the lens driving device 100 of the disc player according to the present invention, a pair of yokes 21 each having a magnetic field forming magnet 20 fixed on a plate-like actuator base 10 are disposed opposite to each other with a predetermined magnetic gap therebetween. Are fixed to the actuator base 10 by a plurality of screws 12 and moved to the support base 31 fixed on the actuator base 10 by the plurality of screws 12 by four support wires (or linear leaf springs) 32. The movable part 50 suspended in a possible manner is arranged in the magnetic gap of the magnets 20 fixed to the pair of yokes 21 and arranged to face each other.

  Each yoke 21 has an auxiliary yoke portion 21a whose both ends are bent in a U-shape, and the magnet 20 is fixed inside the yoke 21 surrounded by the auxiliary yoke portion 21a by an adhesive or the like. The pair of magnets 20 fixed to the yoke 21 are arranged to face each other with a predetermined magnetic gap, thereby forming different magnetic fields for the focus coil 44 and the tracking coil 45. Details will be described later.

  The movable portion 50 is suspended by four support wires 32 formed of a conductive elastic member so as to be movable up and down and left and right. The support wire 32 is rolled and enlarged at one end to form a lead-out portion 32a. When the support base 31 is formed, a part of the support wire 32 is integrally formed by outsert molding or the like. Similarly, the other end of the support wire 32 is rolled and enlarged to form a connection portion 32b, and is fixed to four protrusions 42b and 43b provided on a holder 40 described later with an adhesive or the like.

  In addition, the movable unit 50 is obtained by winding a focus coil 44 and a tracking coil 45 around a holder 40 having an objective lens 48 fixed therein, and terminals of each winding of the focus coil 44 and the tracking coil 45 are as follows. It is connected by soldering or the like to the connecting portion 32b of the support wire 32 bonded to the four protruding portions 42b and 43b formed so as to protrude on both side surfaces of the holder 40.

  On the other hand, a litz wire or the like (not shown) is connected to the lead portion 32a of the support wire 32, and a drive current is supplied to the tracking coil 45 or the focus coil 44 from the outside. When a drive current is supplied to the tracking coil 45 or the focus coil 44 via the support wire 32, the movable portion 50 moves in the tracking (arrow T in the figure) direction and focus (arrow in the figure) according to the drive current in the magnetic gap. F) is freely shifted in the direction.

  The lens driving device 100 of the disc player according to the disclosed example of the present invention is characterized by the structure of the holder 40 constituting the movable unit 50 described above. The structure of the holder 40 will be described in detail below with reference to FIGS. 2 is a conceptual diagram of the holder 40, FIG. 3 is a structural diagram of the holder 40 used in the lens driving device 100 of the disc player according to the disclosed example of the present invention, and FIG. The external view of the movable part 50 of the state which wound the coil 45 was shown.

  As shown in the conceptual diagram of FIG. 2A, the holder 40 used in the present invention has a substantially rectangular shape from which the left and right side plates in the jitter (arrow J in the figure) direction are removed, and is an aperture that is an optical path of an objective lens (not shown) The upper surface wall 42 on which the portion 41 is formed and a pair of side walls 43 having four projecting portions 42a and 43a that are spaced apart and aligned along the tracking (arrow T in the figure) direction.

  The holder 40 can be obtained by removing left and right side plates (shaded portions (A) and (B) in the figure) aligned along the jitter direction from the conventional bowl-shaped holder structure shown in FIG. 40 is reduced in size and weight.

The holder 40 can increase the natural resonance frequency of the holder 40 in the jitter direction by removing the left and right side plates. As is well known, the natural resonance frequency (or natural frequency) of a structure is generally expressed by the following equation (1).
f = 1 / 2π (k / m) ^1/2 (1)
Here, m is the mass of the structure, and k is the spring constant.

The spring constant k is expressed by the following equation (2).
k = 48EI / L ³ (2)
Here, E is a longitudinal elastic modulus, I is a cross-sectional secondary moment, which is a constant determined by the material of the structure, and L is the length of the structure.

  As shown in the equation (1), the natural resonance frequency (f) of the structure is inversely proportional to the 1/2 power of the mass (m) of the structure. Therefore, the holder 40 is reduced in mass by removing the left and right side plates, and the natural resonance frequency in the jitter direction is increased.

  Further, as shown by the equation (2), the spring constant (k) of the structure is inversely proportional to the cube of the length of the structure (length in the jitter direction) (L). Therefore, by removing the left and right side plates, the holder 40 is shortened in the jitter direction, and the natural resonance frequency in the jitter direction is increased. That is, the natural resonance frequency in the jitter direction formed by the mass and dimensions of the substantially rectangular holder 40 can move to a significantly higher range than a holder having a conventional structure. In the case where the upper wall 42 bends due to the removal of the left and right side plates, the holder 40 may be provided with a reinforcing plate 47 having an opening 46 shown in FIG. May be provided on the inner surface of the upper surface wall 42.

  Next, the structure of the holder 40 used in the lens driving device 100 of the disc player according to the disclosed example of the present invention will be described with reference to FIG. 3A is a top view of the holder 40, FIG. 3B is a side view when the holder 40 is viewed from the direction of the jitter (arrow J in the figure), and FIG. A side view when viewed from the tracking (arrow T in the figure) direction is shown.

  The holder 40 is formed of a high-rigidity plastic such as polycarbonate or LCP (liquid crystal polymer) or a resin made of a nonmagnetic material, and has a substantially rectangular shape as a whole. In the holder 40, an opening 41 serving as an optical path of the objective lens 48 is formed at substantially the center of the upper surface wall 42, and concave grooves are formed so as to protrude on both sides (tracking direction, arrow T in the figure) of the upper surface wall 42. An arm portion 42a is formed, and a protruding portion 42b is formed on the outer side of the arm portion 42a so as to be substantially flat with the upper surface wall 42. Further, the pair of side wall portions 43 disposed opposite to each other in the focus (arrow F in the drawing) direction of the holder 40 protrudes from the arm portion 43a disposed opposite to and substantially parallel to the arm portion 42a of the upper surface wall 42 at the tip portion. A portion 43b is formed, and a concave winding groove 43c is formed on the outer peripheral surface.

  The winding groove 43c of the side wall portion 43 is a winding portion (shaded portion (c) portion in the figure) provided for the focus coil 44, and the winding portion has a depth of a predetermined number of turns in the winding portion. When the focus coil 44 is wound, the outermost periphery of the focus coil 44 is substantially flat with respect to the outer peripheral edge portion of the upper surface wall 42 in the tracking direction, and the outer peripheral edge of the upper surface wall 41 in the jitter (arrow J in the figure) direction. It forms so that it may become substantially flat with respect to a part.

  The arm portions 42a on both sides of the upper surface wall 42 and the arm portions 43a of the pair of side wall portions 43 constitute a pair of winding portions for the tracking coil 45 (hatched (d) portions in the figure). The depth of the groove is formed so that the outermost periphery of the tracking coil 45 is substantially flat with respect to the focus direction and the jitter direction of the upper surface wall 42 in a state where the tracking coil 45 having a predetermined number of turns is wound around the winding portion. ing.

  As described above, the focus coil 44 and the tracking coil 45 are wound around the holder 40 around a predetermined winding portion, and the objective lens 48 is fixed inside the holder 40, whereby the lens driving device 100 of the disc player shown in FIG. The movable part 50 to be completed is completed. 4A is a top view of the movable unit 50, FIG. 4B is a side view of the movable unit 50 viewed from the jitter direction, and FIG. 4C is a side view of the movable unit 50 viewed from the tracking direction. A side view when viewed is shown.

  In the movable portion 50, the terminal of the focus coil 44 is led out from a pair of projecting portions 43 b formed on the side wall portion 43, for example, and the tracking coil 45 is formed on the upper wall 42 and the arm portions 42 a and 43 a formed on the side wall portion 43. For example, and is led out from a pair of protrusions 42 b formed on the upper surface wall 42. Therefore, the movable part 50 adheres the protruding part 42 b of the upper surface wall 42 and the protruding part 43 b of the side wall part 43 to the four support wires 32, and turns each winding to each connection part 32 b formed on the four support wires 32. When the terminal is soldered, a drive current is supplied to the focus coil 44 and the tracking coil 45 in a state of being suspended by the four support wires 32.

  Next, the driving operation of the movable unit 50 used in the lens driving device 100 of the disc player will be described with reference to FIG. FIG. 5A is a plan view showing only the movable portion 50 suspended from the support wire 32 and the yoke 21 portion to which the magnet 20 disposed so as to sandwich the movable portion 50 from both sides is fixed. FIG. 5B is a schematic view showing a part of the magnet 20, the auxiliary yoke portion 21a, the tracking coil 45, and the like. FIG. 5C is a schematic view showing a part of the magnet 20 and the focus coil 44. is there. Hereinafter, the middle point of the circle in the figure indicates the direction of current or magnetic flux penetrating from the back surface of the paper toward the front surface, and the middle cross of the circle indicates the direction of current or magnetic flux penetrating from the front surface of the paper toward the back surface. To do.

  FIG. 5A shows a state in which a movable part 50 suspended from four support wires 32 is arranged at the approximate center of a pair of yokes 21 to which magnets 20 arranged to face each other with a predetermined magnetic gap are fixed. ing. As shown in FIG. 5A, the magnet 20 fixed to the yoke 21 disposed oppositely has an N pole on the movable portion 50 side and an S pole on the yoke 21 side. The magnetic flux of the magnet 20 is directed to the direction of the opposing magnet 20 (jitter direction) immediately after being emitted from the magnet 20 in the vicinity of the approximate center of the movable portion 50 (mainly the region where the focus coil 44 is disposed). 44, but then repel each other to form a magnetic path directed in the vertical direction (focus direction) of the magnet 20. The magnetic flux of the magnet 20 in the vicinity of the tracking coil 45 passes through the tracking coil 45 in the direction of the opposing magnet 20 (jitter direction) immediately after being emitted from the magnet 20 as shown by the dotted line arrow in the figure, but then left and right. A magnetic path toward the auxiliary yoke portion 21a is formed.

  Accordingly, the focus coil 44 is somewhat affected by the magnetic field from the surface of the magnet 20 toward the left and right auxiliary yoke portions 21a. However, since the focus coil 44 is disposed substantially at the center of the magnet 20, the direction of the opposing magnet 20 (jitter direction). The influence of the magnetic field toward) becomes dominant. The tracking coil 45 is somewhat affected by the magnetic field directed in the direction of the opposing magnet 20 (jitter direction). However, since the S pole auxiliary yoke portion 21 a is disposed close to the magnet 20, the surface of the magnet 20. The influence of the magnetic field from the left to the left and right auxiliary yoke portions 21a becomes dominant.

  When the driving current in the direction shown in FIG. 5B is supplied to the tracking coil 45 in the magnetic field described above, the movable part 50 receives a driving force in the direction of arrow T in the figure according to the Fleming left-hand rule. Further, when the drive current is supplied in the direction opposite to the above-described direction, the drive force is received in the direction opposite to the arrow T direction in the figure. That is, the movable part 50 is driven in the tracking direction.

  Further, when the drive current in the direction of the arrow shown in FIG. 5C is supplied to the focus coil 44, the movable portion 50 is moved in the direction F (through the paper surface from the back surface to the front surface) in accordance with Fleming's left-hand rule. Receives driving force. Further, when the drive current is supplied in the direction opposite to the arrow direction shown in the figure, a drive force in a direction penetrating the paper surface from the front surface to the back surface is received. That is, the movable part 50 is driven in the focus direction.

  As described above, in the movable unit 50 used in the lens driving device 100 of the disc player according to the disclosed example of the present invention, the outermost periphery of the focus coil 44 and the tracking coil 45 wound around the holder 40 is in the jitter direction of the top wall 42. Since it forms so that it may become substantially flat with respect to an outer periphery part, it becomes possible to arrange | position the movable part 50 with respect to the magnet 20 arrange | positioned facing, and can improve the drive force of a magnetic circuit. .

  Next, a lens driving device 200 for a disc player according to an embodiment of the present invention will be described with reference to FIG. 6A is a plan view of the lens driving device 200 of the disc player without the actuator base 10, and FIG. 6B is a side view of the lens driving device 200 of the disc player.

  In the lens driving device 200 of the disk player according to the embodiment of the present invention, a pair of L-shaped yokes 23 each having a magnet 22 fixed on a plate-like actuator base 10 are arranged to face each other with a predetermined magnetic gap, and a plurality of screws. 12, and a movable portion 80 suspended by four support wires 32 on a support base 31 fixed on the actuator base 10 by a plurality of screws 12 is formed in a magnetic gap formed by a pair of yokes 23. It is arranged and arranged.

  The difference between the embodiment of the present invention and the disclosed example is that the shape of the holder 60 constituting the movable portion 80 and the focus coil and tracking coil are formed by the flat plate-shaped printed coil 70. Accordingly, a magnet 22 magnetized in two divided multipoles is used.

  First, the structure of the holder 60 will be described with reference to FIG. 7A is a top view of the holder 60, FIG. 7B is a side view of the holder 60 viewed from the jitter direction, and FIG. 7C is a view of the holder 60 viewed from the tracking direction. The side view of was shown.

  As shown in FIG. 7, the holder 60 has a substantially square shape as a whole and is formed with an opening 61 serving as an optical path of the objective lens 48 at the center of the upper surface wall 62. A protrusion 62a protruding in the direction of the arrow T) is formed, and the protrusion 62a of the upper surface wall 62 is formed at the tip of a pair of side walls 63 spaced apart and aligned along the tracking direction connected to the upper surface wall 62. A protruding portion 63a is formed so as to face each other. Similarly to the holder 40 used in the disclosed example, by removing the left and right side plates aligned along the jitter direction of the holder 60, the mass of the holder 60 is reduced, and the natural resonance frequency in the jitter direction is increased. Moreover, as shown in FIG.7 (c), you may comprise so that the mass of the holder 60 may be further reduced by providing the opening window 63b in the approximate center of the side wall 63 of the holder 60. FIG.

  That is, the difference between the holder 60 used in the embodiment and the holder 40 of the disclosed example is that the winding part for winding the focus coil and the tracking coil is not provided on the holder 60.

  Next, the structure of the flat printed coil 70 constituting the movable part 80 will be described with reference to FIG. FIG. 8A shows a top view of the flat printed coil 70, and FIG. 8B shows a side view of the flat printed coil 70.

  The flat printed coil 70 is a coil formed by spirally etching one copper foil of a flat double-sided substrate 71 such as glass epoxy, and has one focus coil 72a having a protective film formed on the surface thereof. It consists of four tracking coils 72b.

  For example, a focus coil 72a is formed in the approximate center of the substrate 71 from the positional relationship with the magnet 22 magnetized with two-divided multipole magnets, which will be described later. Four tracking coils 72b are arranged at positions facing and separated from the center line of the focus coil 72a (A-A portion in the figure).

  The terminal of the focus coil 72a is wired to the output terminal 73a for the focus coil 72a formed on the other copper foil of the substrate 71 by a through hole or the like, and is soldered to one connection portion 32b of the support wire 32 by a lead wire (not shown). Attached. Further, the ends of the four tracking coils 72b connected in series with each other are wired to the output terminal 73b for the tracking coil 72b formed on the other copper foil of the substrate 71 by a through hole or the like, and are supported by a lead wire (not shown). 32 is soldered to the other connecting portion 32b. The flat printed coil 70 is a flat printed coil having a large number of turns by laminating a plurality of substrates 71 on which a focus coil 72a and a tracking coil 72b are formed and connecting each coil by a through hole or the like. 70 is also acceptable.

  The objective lens 48 is fixed inside the holder 60 described above, and the flat printed coil 70 is fixed with adhesive or the like on both side surfaces of the holder 60 in the jitter direction, that is, in the removed left and right side plate regions. The movable portion 80 constituting the lens driving device 200 of the disc player according to the embodiment shown in FIG.

  The movable unit 80 used in the embodiment is configured so that the coil surface is parallel to both the focus direction and the tracking direction by fixing the flat printed coil 70 to both side surfaces of the holder 60 in the jitter direction. Yes.

  The movable part 80 bonds the protrusions 62 a of the upper surface wall 62 and the protrusions 63 a of the side wall part 63 to the four support wires 32, and solders the ends of the windings to the connection parts 32 b formed on the support wire 32. As a result, the drive current is supplied to the focus coil 72a and the tracking coil 72b while being suspended by the support wire 32.

  Next, the driving operation of the movable unit 80 used in the lens driving device 200 of the disc player will be described with reference to FIG. 10A shows the positional relationship between the magnet 22 and the flat printed coil 70 when the movable portion 80 is disposed in the magnetic gap, and FIG. 10B shows the magnet 22 and the substrate 71 formed on the positional relationship. FIG. 10C shows a positional relationship between the focus coil 72a and the tracking coil 72b formed on the substrate 71. FIG.

  The magnet 22 used in the lens driving device 200 of the disc player is a rectangular plate material having two different first magnetic poles (N poles) and second magnetic poles (S poles), and one magnet is divided into two. The first magnetic pole (N pole) and the second magnetic pole (S pole) are formed adjacent to each other by pole magnetization, or magnets magnetized with a single pole on the N pole and S pole are stacked vertically. Formed.

  As shown in FIG. 10A, the focus coil 72 a is arranged so as to be crotched between the N pole and the S pole of the magnet 22. With this arrangement, a driving force in the focus direction is generated. Of the four tracking coils 72b, the two tracking coils 72b are arranged on the N pole side of the magnet 22 and are arranged so that about half of the tracking coil 72b in the tracking direction enters the magnetic field of the magnet 22. Similarly, the other two tracking coils 72b are arranged on the south pole side of the magnet 22 and arranged so that about half of the tracking coil 72b in the tracking direction enters the magnetic field of the magnet 22. With this arrangement, only a part of the winding portion of the tracking coil 72b is affected by the magnetic field and a driving force in the tracking direction is generated.

  As shown in FIG. 10B, the focus coil 72a is arranged so as to be crotched between the N pole and the S pole of the magnet 22, so that a drive current is supplied to the focus coil 72a from the front to the front. The movable portion 80 receives a driving force in the direction of arrow F in the drawing, that is, in the focus direction. When the direction of the drive current is reversed, a drive force in the direction opposite to the arrow F direction is received. Further, as shown in FIG. 10 (c), the pair of upper and lower tracking coils 72b are arranged on the N pole side and the S pole side of the magnet 22, so that the drive current in the direction indicated by the arrow in the figure is applied to the tracking coil 72b. When supplied, the movable portion 80 receives a driving force in a direction from the top of the drawing indicated by T in FIG. Further, when the direction of the drive current is reversed, a drive force in the direction opposite to the T direction in the figure is received.

  As described above, the movable unit 50 used in the lens driving device 200 of the disc player according to the embodiment of the present invention does not include the winding unit in the holder 60 and removes the left and right side plates aligned along the jitter direction of the holder 60. Since the flat printed coil 70 having the focus coil 72a and the tracking coil 72b formed in the region is fixed with an adhesive or the like, the mass and size of the holder 60 are reduced, and the holder 60 is bent or twisted. It can be reinforced. In addition, the movable portion 80 formed by the flat printed coil 70 can be disposed close to the magnet 22 and the driving force of the magnetic circuit can be further improved.

  As described above, the holders 40 and 60 used in the disclosure examples and embodiments of the present invention reduce the length in the jitter direction by removing the left and right side plates, and reduce the mass of the holders 40 and 60. It was possible to obtain the following electrical characteristics.

  FIG. 11 is a diagram illustrating the electrical characteristics of the movable parts 60 and 80 according to the disclosure example and the embodiment. The horizontal axis represents frequency, and the vertical axis represents gain and phase. In the figure, the dotted line indicates the amplitude characteristic, and the solid line indicates the phase characteristic. As shown in FIG. 11, a phase is observed in the vicinity of 10 kHz, but a phase delay does not occur in the vicinity of approximately 100 kHz. That is, since the natural resonance frequency has been moved to a high frequency of 100 kHz or higher, the servo system can operate stably even when the disc player is used at double speed or quadruple speed.

FIG. 3 is a structural diagram of a lens driving device of a disc player according to a disclosed example of the present invention. The conceptual diagram of the holder used for the lens drive device of the disc player by the example of an indication of this invention. FIG. 4 is a structural diagram of a holder used in a lens driving device of a disc player according to a disclosed example of the present invention. FIG. 6 is an external view of a movable part used in a lens driving device of a disc player according to a disclosed example of the present invention. The figure explaining operation | movement of the movable part which comprises the lens drive device of the disc player by the example of an indication of this invention. 1 is a structural diagram of a lens driving device of a disc player according to an embodiment of the present invention. 1 is a structural diagram of a holder used in a lens driving device of a disc player according to an embodiment of the present invention. FIG. 4 is a structural diagram of a flat printed coil constituting a movable part used in a lens driving device of a disc player according to an embodiment of the present invention. FIG. 3 is a structural diagram of a movable portion constituting a lens driving device of a disc player according to an embodiment of the present invention. The figure explaining operation | movement of the movable part which comprises the lens drive device of the disc player by the Example of this invention. The figure which shows the electrical property of the lens drive device of the disc player by this invention. The figure which shows the electrical property of the lens drive device of the disc player in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Actuator base 20 ... Magnet 21 ... Yoke 31 ... Support base 32 ... Support wire 44 ... Focus coil 45 ... Tracking coil 48 ... Objective lens 50 ... Movable part 100 .. Lens player lens drive device

Claims (3)

A lens drive device for a disc player,
A holder having an upper surface wall to which an objective lens is fixed and a pair of side walls connected to the upper surface wall and spaced apart from each other in the tracking direction; and an opening provided between the pair of side walls;
A pair of flat printed coils attached to both side surfaces of the top wall and the pair of side walls so as to close the opening;
A lens driving device comprising: A lens drive device for a disc player,
A holder having an upper surface wall to which an objective lens is fixed and a pair of side walls connected to the upper surface wall and spaced apart from each other in the tracking direction; and an opening provided between the pair of side walls;
A pair of flat printed coils attached to both side surfaces of the pair of side walls so as to close the opening;
A pair of magnets that are arranged opposite to each other with a magnetic gap between each of the pair of flat printed coils,
A lens driving device comprising: A positioning projection that is formed in an annular shape standing from the upper surface wall and positions the objective lens on the inner side to position the objective lens on the upper surface wall;
3. The lens driving device according to claim 1, wherein a width of the positioning convex portion in a jitter direction and a width of the upper surface wall in the jitter direction are formed to be equal to each other.

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