JP4088777B2 - Objective lens holder and objective lens driving device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an objective lens driving device used for an optical pickup of an optical disk drive, and more particularly to an objective lens holder thereof.
[0002]
[Prior art]
An optical disc drive reads information recorded on an optical disc (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 the optical disk or write information to the optical disk. Yes.
[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 disc and guides the reflected light to a photodetector. The optical system includes an objective lens disposed so as to face the optical disc.
[0004]
The objective lens used in the optical pickup is focused on the focus direction along the optical axis and the track direction along the radial direction of the optical disc so that the laser beam is accurately focused on the recording surface (track) of the optical disc driven to rotate. The position needs to be accurately controlled. Recently, with the improvement in recording density, there is an increasing need to remove or suppress the influence of warping of the optical disc, and the objective lens needs to be tilted.
[0005]
A conventional objective lens driving device elastically supports an objective lens holder that holds an objective lens by a plurality of suspension wires in order to enable focusing control, tracking control, and tilting control. Further, a focusing coil, a tracking coil, and a tilting coil are wound or attached to the objective lens holder, and these coils are partially positioned in the 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 tilt of the objective lens (see, for example, 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 disposed 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 the base 19. As a result, the lens holder 12 can move in the focusing direction (vertical direction in the figure) and the tracking direction (front and back direction in the figure) and 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 so that it can tilt.
[0010]
The two combinations 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 sting coil 15 is located in each magnetic gap. ing. FIG. 2 shows the positional relationship between the effective magnetic field region of the magnetic circuit by the combination of the yoke 16 and the magnet 17 and each coil.
[0011]
In the above-described configuration, if an appropriate current is supplied to 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 disk.
[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 it is difficult to reduce the size because the tracking coil and the tilting coil are arranged in the vertical direction on the side surface of the lens holder.
[0014]
In addition, the objective lens driving device has a problem that the tracking coil and the tilting coil have to be attached to the side surface of the lens holder, which is troublesome and expensive to manufacture.
[0015]
Some objective lens driving devices that can be expected to be miniaturized have a coil printed on a printed circuit board (for example, Japanese Patent Application Laid-Open No. 2001-273656), but have a problem that the manufacturing process is complicated and expensive.
[0016]
In addition, the magnet has to be subjected to complicated multipolar magnetization, which not only increases the cost, but also causes factors such as a decrease in acceleration sensitivity and a deterioration in tilt characteristics due to the neutral zone.
[0017]
Therefore, an object of the present invention is to provide an objective lens holder having a novel structure and to provide a small and inexpensive objective lens driving device that can be easily assembled.
[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 a winding frame portion (552), the plurality of tilting coil winding frame portions (552) serve as cores of the focusing coil winding frame portions (50, 55). At the same time , the objective lens holder (43) is obtained in which the focusing coil is wound with the plurality of tilting coil reels as a single core .
[0019]
Specifically, the objective lens holder (43) includes an upper member (50) and a lower member (55), and the upper member (50) is a first flange (50) of the focusing coil winding frame. The plurality of tilting coil winding frames, wherein the lower member (55) projects from the second flange (551) of the focusing coil winding frame portion and one surface of the second flange. And the first flange (50) is attached to the plurality of tilting coil reels (552) such that the first flange (50) is disposed opposite to the second flange (552). Yes.
[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 reels (552) are respectively provided. The wound tilting coil (70) wound, and the focusing coil (80) wound around the plurality of tilting coil reels (552) around which the tilting coil (70) is wound. The tracking coils (100) wound around the hook portions (504, 554), a plurality of suspension wires (44) for supporting the objective lens holder (43), and the plurality of suspension wires (44) A fixed portion (41) for fixing and supporting the rear end of the lens, and the objective lens holder (43) is sandwiched along the predetermined direction fixed to the fixed portion (41) And a magnetic circuit (45, 46) including a pair of two-pole magnetized magnets (46) arranged opposite to each other, and the tilting coil (70), the focusing coil (80), and the tracking coil (100). An objective lens driving device characterized in that focusing control, tracking control, and tilting control of the objective lens (42) can be performed by controlling the current to be supplied to each.
[0021]
Note that the reference numerals in the parentheses are given only for easy understanding of the present invention, and do not limit the present invention.
[0022]
DETAILED DESCRIPTION OF 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 the 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 (see FIG. 3) that support the objective lens holder 43 in a swingable manner with respect to the base 41. Only two suspension wires 44, 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 constitutes an optical pickup. The optical base is attached to the guide bar so as to be movable along the radial direction (tracking direction Tr) of the optical disc introduced into the optical disc apparatus. In addition, a laser diode, a photodetector, and a predetermined optical system are attached to the optical base. Laser light from the laser diode is irradiated onto the optical disc through the objective lens 42, and the reflected light is guided to the photodetector. It is configured to be.
[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 is provided with a yoke 45. And tilting in the tracking direction (Tr) based on the relationship with the magnetic field generated by the magnet 46 (rotating with an axis parallel to the tangential direction Tg as a rotation axis), and moving along the tracking direction (Tr), Or 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 at the center thereof. 501 is formed. Further, four rectangular holes 502 for inserting a part of the yoke 45 are formed in symmetrical positions near the four corners of the upper member 50. 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 bonded and fixed, and a U-shaped plate portion 451 and a flat plate portion 452. And a bottom plate portion 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 are configured in a relationship of W1 <W2. The yoke 45 has a thick 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 453a is positioned below the objective lens holder 43. Thus, the objective lens actuator can be reduced in size and the magnetic force acting on the lens holder can be enhanced.
[0031]
The upper member 50 is also formed with fixing portions 503 for fixing the suspension wire 44 on both sides of 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 are projected along the tangential direction in the vicinity of the end portions thereof. Is formed.
[0032]
On the other hand, as shown in FIG. 5 (b), the lower member 55 includes a plate-like portion 551 having a substantially square shape (a surface facing the upper member 50 is substantially square) and a vertical direction from one surface of the plate-like portion 551. And a tilting coil winding frame portion 552 that protrudes from the center. The size of the plate-like portion 551 is the same as that of the upper member 50 at least in the tangential direction (Tg).
[0033]
A through hole 553 for allowing the laser beam to pass therethrough is formed at the center of the plate-like portion 551. In addition, four rectangular holes for inserting a part of the yoke 45 are formed in the vicinity of the four corners of the plate-like portion 551. The tilting coil winding frame part 552 is formed so as to surround the square hole incompletely.
[0034]
Furthermore, the lower member 55 has four second hook portions 554 for winding the tracking coil on both sides of the tangential direction (Tg) in the vicinity of the end portions along the tangential direction. It is formed 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 arranged in this order on the tilting coil winding frame portion 552. It is wound.
[0036]
More specifically, as shown in FIG. 7, the tilting coil 70 is wound around each of the four tilting coil winding frame portions 552 in order. Thereafter, as shown in FIG. 8, the focusing coil 80 is wound using the four tilting coil winding frame portions 552 around which the tilting coil 70 is wound as a single 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. The state is shown in FIG.
[0038]
In the state shown in FIG. 9, when the entire objective lens holder 43 is regarded as a focusing coil winding frame portion, 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 core.
[0039]
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. Further, 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. Each pair of the first hook portion 504 and the second hook portion 554 constitutes four tracking coil winding frame portions for winding the tracking coil.
[0040]
After that, as shown in FIG. 10, the tracking coil 100 is wound around the four tracking coil winding frames, and the objective lens 42 is attached as shown in FIG.
[0041]
The 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 end of each suspension wire 44 fixed in a penetrating state is connected. On the other hand, a lead wire 120 is connected to the connection terminal to which the tilting coil 70 is connected, as shown in FIGS.
[0042]
As shown in FIGS. 12 and 13, the lead wire 120 is fixed through the fixing portion 503, and then bent downward and is used for the tilting coil 70 provided on the lower member 55 of the objective lens holder 43. Connected to the 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 around which the coils 70, 80 and 100 are wound and the suspension wire 44 is attached. The magnet 46 is a dipole 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 disposed in the magnetic gap of the magnetic circuit created by the combination of the yoke 45 and the magnet 46. . Thereby, 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]
Since the objective lens holder according to the present embodiment does not require a space dedicated to the tilting coil, it can be miniaturized. Thereby, miniaturization of the objective lens driving device can also be realized.
[0046]
Although the present invention has been described with reference to one embodiment, the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the example in which the objective lens holder is divided into two in the vertical direction has been described. However, the objective lens holder may be divided in any manner as long as the tilting coil can be wound.
[0047]
【The invention's effect】
According to the present invention, in an objective lens holder for an optical pickup, comprising a focusing coil winding frame for winding a focusing coil and a plurality of tilting coil windings for winding the tilting coil. Since the plurality of tilting coil reels also serve as the cores of the focusing coil reels, it is possible to reduce the size of the objective lens driving device. it can.
[0048]
In addition, since the objective lens holder is composed of a plurality of members, a coil can be easily wound around the objective lens holder, and an objective lens driving device that is easy to assemble and inexpensive can be realized.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a conventional objective lens driving device.
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. 1; FIG.
FIG. 3 is a perspective view of an objective lens driving device according to an embodiment of the present invention.
4 is a perspective view showing a state in which the top cover of the objective lens driving device of FIG. 3 is removed. FIG.
5 is a perspective view of (a) an upper member and (b) a lower member of an objective lens holder used in the objective lens driving device of FIG. 3. FIG.
6 is a perspective view of a yoke used in the objective lens driving device of FIG. 3. FIG.
7 is a perspective view showing a state in which a tilting coil is wound around the lower member of FIG. 5B. FIG.
8 is a perspective view showing a state in which a focusing coil is wound around the lower member in the state shown in FIG. 7. FIG.
9 is a perspective view showing the objective lens holder in a state where the upper member in FIG. 5 (a) is attached to the lower member in the state shown in FIG.
10 is a perspective view showing a state where a tracking coil is wound around the objective lens holder in the state shown in FIG. 9. FIG.
11 is a perspective view showing a state in which an objective lens is attached to the objective lens holder in the state shown in FIG.
12 is a perspective view showing a state in which a suspension wire and a lead wire are attached to the objective lens holder in the state shown in FIG. 11. FIG.
13 is a perspective view of the objective lens holder in the state of FIG. 12 as viewed from the lower surface side.
14 is a perspective view showing a state in which the objective lens holder in the state shown in FIG. 12 is combined with a magnetic circuit composed of a yoke and a magnet.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 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 board part 452 Flat board part 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-like portion 552 Tilting coil winding frame portion 553 Through hole 554 First Two hook portions 601, 602, 603 Connection terminal 70 Tilting coil 80 Focusing coil 100 Tracking coil 120 Lead wire

Claims (11)

In an objective lens holder that is used for an optical pickup and includes a focusing coil winding part for winding a focusing coil and a plurality of tilting coil winding parts for winding a tilting coil.
The plurality of tilting coil reels also serve as the focusing coil reels, and the focusing coils are wound using the plurality of tilting coil reels as a single core. Objective lens holder.   2. The objective lens holder according to claim 1, wherein the objective lens holder includes a plurality of members combined with each other, and when the plurality of members are in a state before the plurality of members are combined, An objective lens holder, wherein the tilting coil can be wound around the objective lens holder.   3. The objective lens holder according to claim 2, wherein the plurality of members are an upper member and a lower member, the upper member constitutes a first flange of the focusing coil winding frame, and the lower member is A second flange of the focusing coil winding frame portion and the plurality of tilting coil winding frame portions projecting on one surface of the second flange are configured, and the first flange is the second flange. An objective lens holder, wherein the objective lens holder is attached to the plurality of tilting coil reels so as to face the flange.   4. The objective lens holder according to claim 3, wherein opposing surfaces of the first and second flanges are each substantially square, and the plurality of tilting coil winding portions are provided in the vicinity of the four corners of the opposing surface. An objective lens holder.   5. The objective lens holder according to claim 4, wherein hook portions for winding the tracking coil project along the predetermined direction on both sides of a pair of surfaces perpendicular to the predetermined direction of the first and second flanges. An objective lens holder, wherein the objective lens holder is formed as described above. An objective lens holder according to any one of claims 1 to 5, 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 disposed so as to sandwich the objective lens holder along the predetermined direction,
An objective lens driving device capable of performing focusing control, tracking control and tilting control of the objective lens 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,
First and second connection terminals connected to the tracking coil and / or the focusing coil, and a third connection terminal connected to the tilting coil,
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.   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 of penetrating the fixing portion, and tip portions thereof are the objective lens holder. An objective lens driving device, wherein the objective lens driving device is connected to a connection terminal on a side surface of the objective lens. The objective lens driving device according to claim 6,
In addition, with a lead wire,
The lead wire is fixed to the fixing portion on the side surface of the objective lens holder in a state of passing through the fixing portion, and the tip end portion thereof is bent to 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 according to any one of claims 1 to 5, an objective lens holder drive circuit in which a coil is wound around the objective lens holder, and a part of the objective lens drive circuit. A magnetic circuit including a yoke member and a magnet arranged so as to
The yoke member has an insertion portion that is 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. The objective lens driving device according to claim 10, wherein the yoke member includes a bottom plate portion that connects the insertion portion and the flat plate portion in a U-shaped cross section.
The bottom plate portion includes a thick portion that thickens a portion connected to the insertion portion, and a thin portion that thins a portion connected to the flat plate portion. .

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