JP2002245646A - Object lens driving device and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an object lens driving device which drives an object lens for condensing light onto the recording surface of an optical disk even in the tilt direction of the optical axis of the object lens in addition to the focusing direction and the tracking direction in order to perform excellent recording/ reproducing in the optical disk device made high in density. SOLUTION: In the object lens driving device, four linear supporting members are fixedly inserted into a hole provided in the side surface of a lens holder, and two supporting members, each in which a coil shaped part or a bending part is provided at its middle part, are fixed to a groove provided in the side surface of the lens holder. Also, two supporting members, which are fixed along the groove provided in the side surface of the lens holder, are fixed to the side nearer to the object lens than the center of the fixed position of four linear supporting members in the direction of the optical axis of the object lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device for driving an objective lens for condensing light on a recording surface of an optical disk in a focusing direction, a tracking direction, and a tilt direction of an optical axis of the objective lens, and an optical disk device. .

[0002]

2. Description of the Related Art In order to perform good recording / reproduction in an optical disk device with a high density, an objective lens for condensing light on a recording surface of an optical disk is added to a focusing direction and a tracking direction, and an optical axis of the objective lens is provided. There is a demand for an objective lens driving device that also drives in the tilt direction of the optical disk and corrects the tilt of the optical disk. Such an objective lens driving device is disclosed in, for example, JP-A-6-162540.

According to JP-A-6-162540,
The supporting material for tiltably supporting the objective lens holder is 8
A parallel linear shape with one end fixed to the side of the objective lens holder and the other end fixed to the supporting and fixing part of the base, so that the movable part can be moved and tilted in three directions: focus direction, tracking direction and tilt direction I support it. In addition, the eight support members are formed by fixing four support members made of a linear elastic body to a side of the objective lens holder and a support member arranged so as to sandwich the objective lens holder in the circumferential direction of the information recording medium. It is configured by cutting at the center of the side of the objective lens holder after fixing to the part.

[0004]

SUMMARY OF THE INVENTION In an optical disc apparatus, light condensed by an objective lens is positioned at high speed, with high accuracy, and with low power consumption in a focusing direction, a tracking direction, and a tilt direction of an optical axis of the objective lens. For this purpose, it is necessary to increase the operation sensitivity of the objective lens driving device in each direction.

[0005] The static operation sensitivity St of the objective lens in the direction of inclination of the optical axis is such that when the driving voltage V is applied, the movable member including the objective lens is supported around the center of the support member that supports the movable portion with respect to the fixed portion. Assuming that the acting moment is M, the spring constant of each support member is ki, and the distance from the center of the support member to the fixed position of each support member is Li,

[0006]

(Equation 1) It is expressed as Here, the subscript i indicates the order of the plurality of support members. From this equation, in order to increase the operation sensitivity in the tilt direction, it is natural that the moment acting around the center of the support member is increased, the spring constant of the support member is reduced, It is necessary to reduce the distance to the fixing position of the support member.

However, in Japanese Patent Application Laid-Open No. 6-162540, eight linear support members are fixed to the side surface of the lens holder, and the distance from the center of the support member to the fixing position of each support member is large. However, the improvement of the operation sensitivity is not always sufficient. After fixing the support made of four linear elastic bodies to the side surface of the objective lens holder and a support fixing portion arranged so as to sandwich the objective lens holder in the circumferential direction of the information recording medium, the objective lens Cutting at the center of the side of the holder into eight support members has a problem that the number of cutting operations increases and the cost increases.

In view of the foregoing, the present invention improves the operational sensitivity and assembles the light when the light condensed by the objective lens is driven and controlled in the focusing direction, the tracking direction, and the inclination direction of the optical axis of the objective lens. It is an object of the present invention to provide an objective lens driving device with improved operability.

[0009]

In order to achieve the above object, an objective lens driving apparatus according to the present invention comprises a movable part including a lens holder for holding an objective lens, a focusing part, a tracking direction, and an objective lens. Four linear support members having four linear support members operably supported in the direction of inclination of the optical axis and two support members provided with a coil-shaped portion or a bent portion in the middle. The member is inserted and fixed in a hole provided on the side surface of the lens holder, and two support members provided with a coil-shaped portion or a bent portion in the middle are fixed by fixing grooves provided on the side surface of the lens holder. did.

[0010] Further, two support members fixed to the fixing grooves provided on the side surface of the lens holder are arranged closer to the objective lens than the center of the fixed position of the four linear support members in the optical axis direction of the objective lens. It was configured to be fixed on the near side. By providing the coil-shaped portion or the bent portion between the two support members as described above, the spring constant of the support member can be reduced, and the operation sensitivity in the tilt direction can be improved. Also,
By fixing the two support members provided with the coil-shaped portions or the bent portions in the middle along the grooves provided on the side surfaces of the lens holder, the workability of assembling the support members can be improved. Further, the fixing position of the two supporting members provided with the coil-shaped portion or the bent portion in the middle is closer to the objective lens than the center of the fixing positions of the four linear supporting members, so that the supporting member is The center of gravity of the movable part can be made close to the center of support of the movable part, so that an objective lens driving device that is statically and dynamically balanced can be realized.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the configuration of the objective lens driving device of the present invention. A lens holder 2 for holding the objective lens 1 includes two focusing coils 3, four tracking coils 4, and two tilt operation coils 1.
1 is attached. The focusing coil 3 and the tilt operation coil 11 are arranged vertically. Here, the focusing coil 3 is shown above and the tilting coil 11 is shown below, but it may be upside down. The movable part 5 includes the objective lens 1, the lens holder 2, the focusing coil 3, the tracking coil 4, and the tilt operation coil 11. Four linear support members 6a, 6b, 6c, 6d
Has one end fixed to the outer edge of the lens holder 2 and the other end fixed to the fixing part 7. The two support members 6e and 6f have a bent portion in the middle, and fix one end to the lens holder 2 and the other end to the fixing portion 7. These six support members 6a, 6b,
The movable portion 5 is operably supported by the fixed portion 7 by 6c, 6d, 6e, and 6f. The permanent magnet 8 opposes the focusing coil 3 and the tracking coil 4 and the tilting coil 11 located on both sides of the objective lens 1 and is fixed to a yoke 9 made of a magnetic material. An inner yoke 10 is provided from the bottom surface of the yoke 9 so as to be located inside the focusing coil 3 and the tilt operation coil 11.

The driving of the objective lens driving device is performed as follows. A drive current is applied to the two focusing coils 3 so that the electromagnetic force generated by the action of the magnetic flux from the permanent magnet 8 is in the same direction, and the movable part 5 is moved in the focusing direction which is the optical axis direction of the objective lens 1. Drive. A drive current is applied to the two tilt operation coils 11 so that the electromagnetic force generated by the action of the magnetic flux from the permanent magnet 8 is in the opposite direction. Thereby, the movable part 5 is driven to rotate around the support center determined by the rigidity balance of the six support members. Also, a drive current is applied to the four tracking coils 4 so that the electromagnetic force generated by the action of the magnetic flux from the permanent magnet 8 is in the same direction, and the movable part 5 is moved in the tracking direction, which is the radial direction of the optical disk. Drive.

Here, six support members 6a, 6b, 6
The mounting method of c, 6d, 6e, 6f will be described with reference to FIG. Four linear support members 6a, 6b, 6c;
6d are holes 12a, 1 provided in the outer edge of the lens holder 2.
2b, 12c, 12d and holes 17a, 1
7b, 17c, and 17d, and fixed to the lens holder 2 and the fixing portion 7 with an adhesive or solder. Here, the support members 6a, 6b, 6c, and 6d are inserted from the lens holder 2 side toward the fixing unit 7, but may be inserted from the fixing unit 7 side toward the lens holder 2. Two support members 6e and 6f having a bent portion in the middle
Is inserted into the holes 17e, 17f provided on the fixing portion 7 on the fixing portion 7 and the lens holder side is positioned along the grooves 13e, 13f provided on the side surface of the lens holder 2, and is fixed with an adhesive or solder. It is fixed to the lens holder 2 and the fixing part 7. The six support members 6a, 6b, 6c, 6
Although not shown, d, 6e, and 6f are electrically connected to the focusing coil 3, the tracking coil 4, the tilt operation coil 11, and solder. It is not necessary to form all six support members with conductive members, provided that at least two of the support members arranged symmetrically with respect to a line passing through the center of the lens are formed of conductive members. Good. That is, a support member formed of a conductive member may be disposed so that the spring action is substantially equal on the left and right.

As in this embodiment, two support members 6e and 6
The support members 6e, 6f
Can be lengthened, and the spring constant can be reduced. As described above, since the operation sensitivity in the tilt direction is inversely proportional to the spring constant of the support member, the operation sensitivity in the tilt direction can be improved by providing a bent portion between the support members 6e and 6f.

A supporting member 6 having a bent portion in the middle
In order to insert and fix both the lens holders e and 6f into the holes of both the lens holder 2 and the fixing portion 7, it is necessary to insert the supporting members 6e and 6f deeply into one of them and bend back to the other. Yes, making work difficult. On the other hand, in this embodiment, the support members 6e and 6
f is fixed by grooves 13e provided on the side surface of the lens holder 2,
Since the operation is performed along 13f, there is no need to turn back the support member, and the operation is facilitated.

Further, in this embodiment, the fixing positions of the two support members 6e and 6f fixed along the grooves 13e and 13f provided on the side surface of the lens holder 2 are as shown in FIG.
In the optical axis direction of the objective lens 1, it is closer to the objective lens 1 than the center of the fixed position of the four linear support members 6a, 6b, 6c, 6d. Thereby, the support center determined by the rigidity balance of the six support members 6a, 6b, 6c, 6d, 6e, 6f can be brought closer to the objective lens 1. As shown in FIG. 3, the objective lens 1 is
Is mounted on the objective lens 1 with respect to the center of the fixed position of the four support members 6a, 6b, 6c, 6d. Therefore, with this configuration, the center of support and the center of gravity of the movable portion 5 can be brought close to each other, and an objective lens driving device that is statically and dynamically balanced can be realized.

A balance weight or the like is attached to the lower part of the lens holder 2 so that the center of gravity of the movable part 5 is on the opposite side of the center of the fixed position of the four support members 6a, 6b, 6c, 6d from the objective lens 1. When it becomes, the support member 6e,
6f in the optical axis direction of the objective lens 1
What is necessary is just to make it the side opposite to the objective lens 1 with respect to the center of the fixed position of four support members 6a, 6b, 6c, 6d. In any case, the fixing positions of the support members 6e, 6f are changed in the optical axis direction of the objective lens 1 by the four support members 6a, 6b,
What is necessary is just to set it as the side near the center of gravity of the movable part 5 with respect to the center of the fixed position of 6c, 6d.

Next, another embodiment of the present invention is shown in FIG.
In this embodiment, the support members 6e, 6
f, supporting members 16e, 1
6f. Thus, the support members 16e, 1
By providing the coil-shaped portion in the middle of 6f, the spring constant can be further reduced, and the operating sensitivity in the tilt direction can be improved. Other configurations and effects are the same as those of the first embodiment.

FIG. 5 is a perspective view of an optical disk device using the above-described objective lens driving device. The disk device includes a disk loading mechanism that transports a disk 51, which is a disc-shaped information recording medium, into the device, and then mounts the disk 51 on a turntable provided on a rotation shaft of a spindle motor 52, and then fixes the disk. The disk loading mechanism includes a disk tray 61, a loading motor (not shown), a gear for transmitting the driving force of the motor, a driving force transmitting member, and a disk clamper 53 for fixing the disk 51 to a turntable of the spindle motor 52. It is constituted by. In the disk loading operation, first, in order to carry the disk 51 into or out of the apparatus, there is an operation in which the disk tray 61 on which the disk 1 is loaded is taken in and out through a carry-in / out hole provided in the front panel 60 of the apparatus. . Further, the disc 1 loaded into the apparatus is mounted on a turntable of a spindle motor 52 and fixed by a disc clamper 53 provided on a surface of the top cover 58 facing the disc 51. The operation includes an optical head 54 for reproducing or recording / reproducing information, and an operation of vertically moving up and down the unit mechanical chassis 55 holding them. When the disk 51 is fixed to the spindle motor 52, the spindle motor 52 rotates at a specified number of revolutions, and reproduces information recorded on the disk 51 by the optical head 54 provided in the unit mechanical chassis 55, Alternatively, information is recorded on the disk 51.

The optical head 54 has a driving means for moving the lens in the radial direction in addition to a driving means for moving the lens in the direction of the disk 51. The unit mechanical chassis 55 includes the spindle motor 52 and the optical head 5.
4 are attached. Vibrations and shocks transmitted from the outside of the device to the unit mechanical chassis 55 are transmitted to the insulator 56a,
Damped by b, c, d (elastic members). The unit mechanical chassis 5 includes the insulators 56a, b, c, and d.
Through a unit holder (not shown). Further, the unit holder is fitted and connected to the mechanical base 57. A circuit board for controlling a spindle motor and the like is attached below the mechanical base 57, and the outside thereof is covered with a bottom cover. The disk device is configured to be incorporated in a computer device or the like with the bottom cover 59 and the top cover 58 attached.

When the optical head 54 is driven to read or write information, it is necessary to drive the objective lens to focus on the information recording on the optical disk surface. When the disk surface is deformed, it is necessary to control the tilt of the lens itself.
Therefore, by applying the objective lens driving device described in the previous embodiment, high-speed and high-accuracy positioning can be performed.

[0022]

As described above, according to the present invention, by providing a coil-shaped portion or a bent portion between two support members, the spring constant of the support member can be reduced, and the operation sensitivity in the tilt direction can be reduced. Can be improved. Further, by fixing two support members provided with a coil-shaped portion or a bent portion in the middle along a groove provided on the side surface of the lens holder, the assembling workability of the support member can be improved. Furthermore, by setting the fixed position of the two support members provided with the coil-shaped portion or the bent portion in the middle closer to the objective lens than the center of the fixed position of the four linear support members,
Since the center of support of the supporting member and the center of gravity of the movable part can be brought close to each other, an objective lens driving device that is statically and dynamically balanced can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an objective lens driving device according to the present invention.

FIG. 2 is a diagram illustrating a method of attaching a support member according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a mounting position of a support member according to the embodiment of the present invention.

FIG. 4 is a diagram showing another embodiment of the present invention.

FIG. 5 is a perspective view of an optical disk device to which the objective lens driving device according to the present invention is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Objective lens, 2 ... Lens holder, 3 ... Focusing coil, 4 ... Tracking coil, 5 ... Moving part, 6
a, 6b, 6c, 6d, 6e, 6f: support member, 7: fixing portion, 8: permanent magnet, 9: yoke, 10: inner yoke, 11: coil for tilting operation, 12a, 12b, 12
c, 12d: holes provided in the lens holder, 12e, 12f
... grooves provided in the lens holder, 17a, 17b, 17c,
17d: holes provided in the fixing portion.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Mitsuo Satake, 1 Kitano, Makino, Mizusawa-shi, Iwate Prefecture Inside Hitachi Media Electronics Co., Ltd. (72) Tetsuo Ito 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Japan Hitachi Image Information System (72) Inventor Shuji Takahashi 1 Kitano, Majo, Mizusawa-shi, Iwate F-term in Hitachi Media Electronics Co., Ltd. 5D118 AA06 AA13 BA01 DC03 EA02 EF07 FA30 FB10 FB12 FB20

Claims (5)

[Claims] 1. An objective lens for condensing light on a recording surface of an optical disk, a lens holder for holding the objective lens, and a movable part including the lens holder being fixed to a fixed part in a focusing direction, a tracking direction, and the objective part. It has four linear support members that are operably supported in the direction of inclination of the optical axis of the lens, and two support members that are provided with a coil-shaped portion or a bent portion in the middle. An objective lens driving device comprising: a through hole for fixing the four linear support members; and a groove for fixing two support members having a coil-shaped portion or a bent portion in the middle. 2. The objective lens driving device according to claim 1, wherein two support members fixed along a groove provided on a side surface of the lens holder are connected to the straight line in the optical axis direction of the objective lens. An objective lens driving device, wherein the four supporting members are fixed on a side closer to the objective lens than a center of a fixing position of the four supporting members. 3. The objective lens driving device according to claim 1, wherein two support members fixed along a groove provided on a side surface of the lens holder are connected to the straight line in the optical axis direction of the objective lens. An objective lens driving device, wherein the fixed portion is fixed on a side closer to the center of gravity of the movable portion than the center of the fixed position of the four support members. 4. The objective lens driving device according to claim 1, wherein at least the two support members are formed of a conductive member. 5. An optical disk device using the objective lens driving device according to claim 1.