JP2004319006A - Objective lens holder and objective lens driver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective lens holder having a new structure that can provide a small and inexpensive objective lens driver which is easily assembled. <P>SOLUTION: This objective lens holder consists of upper and lower members. The upper member 50 is almost plate-like in shape, and has a through hole 501 for mounting an objective lens, a square hole 502 for inserting a yoke, a fixing part 503 for fixing a suspension wire, a first hook part 504 for winding tracking wire, etc. The lower member 55 has an almost plate-shaped plate upper part 551 and tilting coil winding frame parts 552 projected from one surface of the plate upper part, and further has a through hole 553 for pressing laser beams through and a second hook part 554 for winding tracking wire. A tilting coil is wound around each of the tilting coil winding frame parts 552, which are also used as a single winding stem for winding a focusing coil. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an objective lens driving device used for an optical pickup of an optical disk drive, and particularly to an objective lens holder.
[0002]
[Prior art]
Optical disk drives read information recorded on optical disks (CD, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD + R, DVD-R, DVD-RAM, DVD + RW, DVD-RW, etc.). Or a device for writing information. This type of optical disk drive includes an optical pickup for irradiating the optical disk with laser light and detecting the reflected light in order to read information from or write information to the optical disk. I have.
[0003]
In general, an optical pickup includes a laser light source that emits a laser beam, and an optical system that guides the emitted laser beam to an optical disk and guides reflected light thereof to a photodetector. The optical system includes an objective lens arranged to face the optical disk.
[0004]
The objective lens used in the optical pickup is designed so that the laser beam is accurately focused on the recording surface (track) of the optical disk which is driven to rotate, with respect to the focus direction along the optical axis and the track direction along the radial direction of the optical disk. It is necessary to control the position with high accuracy. Further, recently, with the improvement in recording density, the necessity of removing or suppressing the influence of the warp of the optical disk has been increased, and the objective lens also needs to be tilted.
[0005]
A conventional objective lens driving device elastically supports an objective lens holder holding an objective lens with a plurality of suspension wires in order to enable focusing control, tracking control, and tilting control. In addition, a focusing coil, a tracking coil, and a tilting coil are wound or attached to the objective lens holder, and these coils are partially located in a gap of the magnetic circuit. In such a configuration, by controlling the current flowing through each coil, the conventional objective lens driving device can finely adjust the position and inclination of the objective lens (for example, see Patent Document 1).
[0006]
Hereinafter, a conventional objective lens driving device will be described with reference to FIGS.
[0007]
FIG. 1 is a longitudinal sectional view of a conventional objective lens driving device. The illustrated objective lens driving device includes an objective lens 11, a lens holder 12, a focusing coil 13, a tracking coil 14, a tilting coil 15, a yoke 16, a magnet 17, a suspension wire 18, and a base 19.
[0008]
The objective lens 11 is arranged on the upper surface side of the lens holder 12. The focusing coil 13 is wound around the side surface of the lens holder 12, and the tracking coil 14 and the tilting coil 15 are attached to the side surface of the lens holder 12.
[0009]
One end of each of the four suspension wires 18 (only two of which are shown) is fixed to the lens holder 12. The other end of each suspension wire 18 is fixed to a base 19. Accordingly, the lens holder 12 can move in the focusing direction (vertical direction in the figure) and the tracking direction (front and back directions in the figure), and can move in the radial direction of the optical disk (the circumferential direction of the rotating shaft extending in the horizontal direction in the figure). It is elastically supported to be tiltable.
[0010]
The two sets of the combination of the yoke 16 and the magnet 17 form a magnetic circuit, and are arranged such that a part of each of the focusing coil 13, the tracking coil 14, and the tilting and sting coil 15 is located in each magnetic gap. ing. FIG. 2 shows a positional relationship between an effective magnetic field region of a magnetic circuit formed by a combination of the yoke 16 and the magnet 17 and each coil.
[0011]
In the above configuration, if an appropriate current is supplied to each of the focusing coil 13, the tracking coil 14, and the tilting coil 15, the lens holder 12 (and the objective lens 11) is moved and / or tilted accordingly. Thus, the light beam can be correctly focused on the track on the recording surface of the optical disc.
[0012]
[Patent Document 1]
JP 2001-93177 A (FIGS. 7 and 8)
[0013]
[Problems to be solved by the invention]
The conventional objective lens driving device has a problem that downsizing is difficult because the tracking coil and the tilting coil are arranged vertically on the side surface of the lens holder.
[0014]
In addition, this objective lens driving device has a problem in that the tracking coil and the tilting coil must be attached to the side surface of the lens holder, and the manufacture thereof is troublesome and costly.
[0015]
As an objective lens driving device that can be expected to be miniaturized, there is a device in which a coil is printed on a printed circuit board (for example, Japanese Patent Application Laid-Open No. 2001-273656), but there is a problem that the manufacturing process is complicated and costly.
[0016]
Further, the magnet must be subjected to complicated multipolar magnetization, which not only increases the cost but also causes a decrease in acceleration sensitivity due to the neutral zone and a deterioration in the tilt characteristics.
[0017]
Accordingly, an object of the present invention is to provide an objective lens holder having a novel structure, and to provide a compact and inexpensive objective lens driving device that is easy to assemble.
[0018]
[Means for Solving the Problems]
According to the present invention, a focusing coil winding frame (50, 55) for winding a focusing coil (80) and a plurality of tilting coils for winding a tilting coil (70) are used in an optical pickup. In the objective lens holder (43) provided with the winding frame part (552), the plurality of tilting coil winding parts (552) form a core of the focusing coil winding part (50, 55). An objective lens holder (43) characterized in that it also serves as the objective lens holder (43) is obtained.
[0019]
Specifically, the objective lens holder (43) includes an upper member (50) and a lower member (55), and the upper member (50) is connected to the first flange (50) of the focusing coil bobbin. ), Wherein the lower member (55) has a second flange (551) of the focusing coil bobbin portion and the plurality of tilting coil bobbins protrudingly provided on one surface of the second flange. (552), and is attached to the plurality of tilting coil winding frame parts (552) such that the first flange (50) is arranged to face the second flange (552). I have.
[0020]
According to the present invention, the objective lens holder (43), the objective lens (42) held by the objective lens holder (43), and the plurality of tilting coil winding frames (552) are respectively provided. The wound tilting coil (70); and the focusing coil (80) wound around the plurality of tilting coil winding frames (552) around which the tilting coil (70) is wound. A plurality of suspension wires (44) supporting the tracking coil (100) wound around the hook portions (504, 554), the objective lens holder (43), and the plurality of suspension wires (44). And a fixing portion (41) for fixing and supporting the rear end of the objective lens holder (43) fixed to the fixing portion (41) along the predetermined direction. And a magnetic circuit (45, 46) including a pair of two-pole magnetized magnets (46) disposed opposite to each other. The magnetic circuits (45, 46) include the tilting coil (70), the focusing coil (80), and the tracking coil (100). The objective lens driving device is characterized in that focusing control, tracking control, and tilting control of the objective lens (42) can be performed by controlling the current flowing through each of them.
[0021]
It should be noted that the reference numerals in the parentheses are merely provided to facilitate understanding of the present invention, and do not limit the present invention in any way.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0023]
FIG. 3 is a perspective view of the objective lens driving device according to one embodiment of the present invention. FIG. 4 is a perspective view showing a state in which the metal top cover 47 of the objective lens driving device of FIG. 3 is removed.
[0024]
As shown in FIGS. 3 and 4, the objective lens driving device includes a base 41, an objective lens 42, an objective lens holder 43, and four objective lens holders that swingably support the objective lens holder 43 with respect to the base 41. (Only two wires are shown), a pair of yokes 45 fixed to the base 41, and a magnet 46 fixed to each yoke 45.
[0025]
This objective lens driving device is mounted on an optical base of an optical disk driver (not shown) and forms an optical pickup. The optical base is attached to the guide bar so as to be movable in the radial direction (tracking direction Tr) of the optical disk introduced into the optical disk device. A laser diode, a photodetector, and a predetermined optical system are mounted on the optical base. Laser light from the laser diode is applied to the optical disc through the objective lens 42, and the reflected light is guided to the photodetector. It is configured to be closed.
[0026]
As will be described later, a tilting coil, a focusing coil, and a tracking coil are wound around the objective lens holder 43. By appropriately controlling the current flowing through these coils, the objective lens holder 43 And tilts in the tracking direction (Tr) (rotates around an axis parallel to the tangential direction Tg as a rotation axis) based on the relationship with the magnetic field generated by the magnet 46, and moves along the tracking direction (Tr). Alternatively, it moves along the focusing direction (F).
[0027]
Hereinafter, the objective lens holder 43 will be described in detail.
[0028]
The objective lens holder 43 includes an upper member 50 as shown in FIG. 5A and a lower member 55 as shown in FIG.
[0029]
As shown in FIG. 5A, the upper member 50 has a substantially square plate shape (the surface facing the lower member 55 is substantially square), and a through hole for attaching an objective lens is provided in the center thereof. 501 is formed. In the vicinity of the four corners of the upper member 50, four rectangular holes 502 for inserting a part of the yoke 45 are formed at symmetrical positions. The yoke 45 has a shape as shown in FIG.
[0030]
As shown in FIG. 6, the yoke 45 includes a U-shaped plate portion 451 inserted into the square hole 502, a flat portion 452 to which the magnet 46 is adhered and fixed, and the U-shaped plate portion 451 and the flat plate portion 452. And a bottom plate 453 connected in a U-shaped cross section. The bottom plate portion 453 includes a thick portion 453a and a thin portion 453b. The thick portion 453a is adjacent to the U-shaped plate portion 451, and the thin portion is adjacent to the flat plate portion 452. The thickness W1 of the flat plate portion 452 and the thickness W2 of the U-shaped plate portion 451 have a relationship of W1 <W2. The yoke 45 has a thickness 451 inserted into the square hole 502 of the objective lens holder 43, a thin flat plate portion 452 to which the magnet 46 is fixed, and a thick portion 453 a positioned below the objective lens holder 43. Therefore, the size of the objective lens actuator can be reduced, and the magnetic force acting on the lens holder can be strengthened.
[0031]
The upper member 50 is also provided with fixing portions 503 for fixing the suspension wires 44 on both sides in the tracking direction (Tr). Further, on both sides of the upper member 50 in the tangential direction (Tg), four first hook portions 504 for winding the tracking coil protrude in the tangential direction near the ends thereof. Is formed.
[0032]
On the other hand, as shown in FIG. 5B, the lower member 55 has a plate-shaped portion 551 having a substantially square shape (the surface facing the upper member 50 is substantially square) and a vertical direction from one surface of the plate-shaped portion 551. And a tilting coil winding frame 552 protruding from The size of the plate portion 551 is the same as the upper member 50 at least in the tangential direction (Tg).
[0033]
In the center of the plate-shaped portion 551, a through-hole 553 for passing a laser beam is formed. In the vicinity of the four corners of the plate portion 551, four square holes for inserting a part of the yoke 45 are formed. The tilting coil bobbin 552 is formed so as to incompletely surround this rectangular hole.
[0034]
Further, on the lower member 55, on both sides in the tangential direction (Tg), four second hook portions 554 for winding a tracking coil are provided along the tangential direction near the ends thereof. It is formed so as to protrude.
[0035]
The upper member 50 and the lower member 55 described above are combined with each other to form the objective lens holder 43. Before combining them, the tilting coil and the focusing coil are attached to the tilting coil bobbin 552 in this order. It is wound.
[0036]
More specifically, as shown in FIG. 7, the tilting coil 70 is sequentially wound around each of the four tilting coil bobbin portions 552. Thereafter, as shown in FIG. 8, the focusing coil 80 is wound around the four tilting coil winding frame portions 552 around which the tilting coil 70 is wound as a single winding core.
[0037]
Thus, after the tilting coil 70 and the focusing coil 80 are wound around the lower member 55, the upper member 50 is fixed to the lower member 55. FIG. 9 shows this state.
[0038]
In the state shown in FIG. 9, when the entire objective lens holder 43 is regarded as a focusing coil bobbin, the plate-like portions 551 of the upper member 50 and the lower member 55 correspond to flanges. As described above, the four tilting coil winding frame portions 552 correspond to the winding cores.
[0039]
Further, in the state shown in FIG. 9, the central axis of the through hole 501 formed in the upper member 50 and the central axis of the through hole 553 formed in the lower member coincide with each other. The four first hook portions 504 formed on the upper member 50 and the four second hook portions 554 formed on the lower member 55 face each other and form a pair. The pair of the first hook portion 504 and the second hook portion 554 constitute four tracking coil winding portions for winding the tracking coil.
[0040]
Thereafter, as shown in FIG. 10, the tracking coil 100 is wound around four tracking coil winding frames, and the objective lens 42 is attached as shown in FIG.
[0041]
Ends of the tilting coil 70, the focusing coil 80, and the tracking coil 100 are connected to connection terminals 601, 602, and 603. Here, the connection terminals 601 and 602 to which the ends of the focusing coil 80 and the tracking coil 100 are connected are further provided with the fixing portion 503 on the fixing portion 503 formed on the upper member 50 as shown in FIG. One ends of the suspension wires 44 fixed in a penetrating state are respectively connected. On the other hand, as shown in FIGS. 12 and 13, a lead wire 120 is connected to the connection terminal to which the tilting coil 70 is connected.
[0042]
As shown in FIGS. 12 and 13, the lead wire 120 passes through the fixing portion 503 and is fixed, and then bent downward for the tilting coil 70 provided on the lower member 55 of the objective lens holder 43. Connected to connection terminal 603.
[0043]
FIG. 14 shows a state where the yoke 45 and the magnet 46 are combined with the objective lens holder 43 on which the coils 70, 80 and 100 are wound and the suspension wire 44 is attached. The magnet 46 is a two-pole magnetized magnet.
[0044]
As can be easily understood from FIG. 14, a part of each of the tilting coil 70, the focusing coil 80, and the tracking coil 100 is arranged in the magnetic gap of the magnetic circuit created by the combination of the yoke 45 and the magnet 46. . Thus, the objective lens holder 43 moves and tilts according to the current flowing through each coil. That is, tilting control, focusing control, and tracking control can be performed by controlling the current flowing through each coil.
[0045]
The objective lens holder according to the present embodiment does not require a space dedicated to the tilting coil, and thus can be downsized. This makes it possible to reduce the size of the objective lens driving device.
[0046]
As described above, the present invention has been described in accordance with one embodiment, but the present invention is not limited to the above embodiment. For example, in the above-described embodiment, an example has been described in which the objective lens holder is divided into upper and lower parts. However, any division may be used as long as the tilting coil can be wound.
[0047]
【The invention's effect】
According to the present invention, there is provided an objective lens holder for an optical pickup, comprising: a focusing coil frame portion for winding a focusing coil; and a plurality of tilting coil frame portions for winding a tilting coil. Since the plurality of winding frames for the tilting coil also serve as the winding core of the winding frame for the focusing coil, miniaturization can be realized, and thus miniaturization of the objective lens driving device can be realized. it can.
[0048]
In addition, since the objective lens holder is composed of a plurality of members, the coil can be easily wound around the objective lens holder, and an easy-to-assemble and inexpensive objective lens driving device can be realized.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a conventional objective lens driving device.
FIG. 2 is a diagram showing a positional relationship between an effective magnetic field region and each coil in the objective lens driving device of FIG.
FIG. 3 is a perspective view of an objective lens driving device according to one embodiment of the present invention.
4 is a perspective view showing a state where a top cover of the objective lens driving device of FIG. 3 is removed.
5 is a perspective view of (a) an upper member and (b) a lower member of the objective lens holder used in the objective lens driving device of FIG.
FIG. 6 is a perspective view of a yoke used in the objective lens driving device of FIG.
FIG. 7 is a perspective view showing a state in which a tilting coil is wound around a lower member of FIG. 5 (b).
8 is a perspective view showing a state in which a focusing coil is wound around a lower member shown in FIG. 7;
FIG. 9 is a perspective view showing the objective lens holder in a state where the upper member of FIG. 5A is attached to the lower member of FIG. 8;
FIG. 10 is a perspective view showing a state in which a tracking coil is wound around the objective lens holder in the state shown in FIG. 9;
11 is a perspective view showing a state where the objective lens is attached to the objective lens holder in the state shown in FIG. 10;
12 is a perspective view showing a state where a suspension wire and a lead wire are attached to the objective lens holder in the state shown in FIG. 11;
13 is a perspective view of the objective lens holder in the state of FIG. 12 as viewed from the lower surface side.
FIG. 14 is a perspective view showing a state where a magnetic circuit including a yoke and a magnet is combined with the objective lens holder in the state shown in FIG. 12;
[Explanation of symbols]
Reference Signs List 11 Objective lens 12 Lens holder 13 Focusing coil 14 Tracking coil 15 Tilting coil 16 Yoke 17 Magnet 18 Suspension wire 19 Base 41 Base 42 Objective lens 43 Objective lens holder 44 Suspension wire 45 Yoke 451 U-shaped plate portion 452 Flat plate portion 453 Bottom plate portion 453a Thick portion 453b Thin portion 46 Magnet 50 Upper member 501 Through hole 502 Square hole 503 Fixed portion 504 First hook portion 55 Lower member 551 Plate portion 552 Tilting coil winding frame portion 553 Through hole 554 2 hook portions 601, 602, 603 Connection terminal 70 Tilting coil 80 Focusing coil 100 Tracking coil 120 Lead wire

Claims (11)

Used in an optical pickup, in an objective lens holder including a focusing coil winding part for winding a focusing coil and a plurality of tilting coil winding parts for winding a tilting coil,
An objective lens holder, wherein the plurality of tilting coil reels also serve as a core of the focusing coil reel. 2. The objective lens holder according to claim 1, wherein the objective lens holder includes a plurality of members combined with each other, and in a state before the plurality of members are combined, each of the plurality of winding frames for the tilting coil is provided. An objective lens holder characterized in that the tilting coil can be wound therewith. 3. The objective lens holder according to claim 2, wherein the plurality of members are an upper member and a lower member, wherein the upper member forms a first flange of the focusing coil bobbin, and the lower member is A second flange of the focusing coil frame portion and the plurality of tilting coil frame portions projecting from one surface of the second flange, wherein the first flange is the second flange; An objective lens holder attached to the plurality of tilting coil winding frames so as to face the flange. 4. The objective lens holder according to claim 3, wherein the opposing surfaces of the first and second flanges are each substantially rectangular, and the plurality of winding frames for the tilting coil are provided near four corners of the opposing surface. An objective lens holder characterized in that: 5. The objective lens holder according to claim 4, wherein a hook portion for winding a tracking coil protrudes along both sides of a pair of surfaces perpendicular to a predetermined direction of the first and second flanges along the predetermined direction. An objective lens holder characterized in that the objective lens holder is formed in such a way that The objective lens holder according to claim 1, an objective lens held by the objective lens holder, a tilting coil, a focusing coil, a tracking coil, and the objective lens holder. A plurality of suspension wires to be supported, and a magnetic circuit including a pair of two-pole magnetized magnets arranged so as to sandwich the objective lens holder along the predetermined direction,
An objective lens driving device wherein a focusing control, a tracking control, and a tilting control of the objective lens can be performed by controlling a current flowing through each of the tilting coil, the focusing coil, and the tracking coil. . The objective lens driving device according to claim 6,
A first connection terminal connected to the tracking coil and / or the focusing coil, and a third connection terminal connected to the tilting coil;
The objective lens driving device, wherein the first and second connection terminals are disposed on a side surface of the objective lens holder, and the third connection terminal is disposed on a lower surface of the objective lens holder. 7. The objective lens driving device according to claim 6, wherein the plurality of suspension wires are fixed to a fixing portion on a side surface of the objective lens holder in a state where the suspension wires penetrate the fixing portion, and a tip end portion of the objective lens holder. An objective lens driving device connected to a connection terminal on a side surface of the object lens. The objective lens driving device according to claim 6,
In addition, it has a lead line,
The lead wire is fixed to a fixing portion on the side surface of the objective lens holder in a state of penetrating the fixing portion, and its tip is bent toward the lower surface side of the objective lens holder to connect the lower surface of the objective lens. An objective lens driving device connected to a terminal. An objective lens holder for holding an objective lens, an objective lens holder driving circuit in which a coil is wound around the objective lens holder, a yoke member and a magnet arranged to be located in a part of the objective lens driving circuit And a magnetic circuit including
The yoke member has an insertion portion inserted through the objective lens holder and a flat plate portion to which the magnet is fixed, and the insertion portion is thicker than the flat plate portion. An objective lens driving device, characterized in that: The objective lens driving device according to claim 10, wherein the yoke member includes a bottom plate that connects the insertion portion and the flat plate to each other in a U-shaped cross section,
The objective lens driving device, wherein the bottom plate portion includes a thick portion that makes a portion connected to the insertion portion thick, and a thin portion that makes a portion connected to the flat plate portion thin. .

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