JPH07182675A - Optical disc apparatus - Google Patents

Abstract

PURPOSE:To obtain a cartridge type optical disc apparatus in a structure to be thin and compact. CONSTITUTION:A magnetic circuit 9 of a driving device for an objective lens 3 is set within an area of a window 8d of a lower shell 8b of an optical disc 1. Both end parts in a tracking direction of a lens holder 13 holding the objective lens 3 which are faced to a disc are inclined surfaces. Accordingly, it is prevented that the lens holder collide against edges of the outermost and innermost peripheries of the window of the lower sell, and a vertical width of the lens holder is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cartridge type optical disk device for a magneto-optical recording / reproducing disk or the like, and more particularly to a structure for thinning and downsizing.

[0002]

2. Description of the Related Art FIG. 7A shows a schematic structure of an optical disk device portion in a magneto-optical recording / reproducing apparatus. An optical pickup 1 has a magnetic head 2 on one surface and an objective lens 3 on the other surface. A device 4 is provided. The magnetic head 2 and the optical pickup device 4 are driven in the radial direction of the optical disc 1 by a head drive device 5 and a feed motor 6, respectively, and the optical disc 1 is rotated by a spindle motor 7. In such an optical disc device, in recent years, a type in which the optical disc 1 is covered with a cartridge 8 has been sold for the purpose of protecting the optical disc 1. In this cartridge type optical disc, as shown in FIG. 7B, the optical disc 1 is rotatably accommodated in a space formed between an upper shell 8a and a lower shell 8b, and each shell 8a,
8b is provided with windows 8c and 8d. When not in use, the shutters 8e close the windows 8c and 8d. When recording and reproducing, the shutter 8e is laterally moved to open the windows 8c and 8d, and the magnetic head 2 and the objective lens 3 are provided. Is to be inserted into the window.

In the conventional optical pickup device 4, a circuit for driving the objective lens 3 in the focus direction and the tracking direction is provided in a portion other than the lower portion of the objective lens 3, as described in, for example, Japanese Patent Laid-Open No. 61-139945. To form a free space below the objective lens 3 and arrange a reflection mirror in that part to form a free space.
We have been trying to reduce the overall thickness.

[0004]

In such a conventional apparatus, as shown in FIG. 4A, the optical axis of the objective lens 3 is aligned with the center of the window 8d of the lower shell 8b in the disk rotation direction. In addition, the optical disc 1 and the objective lens 3 are opposed to each other with an interval of L3, but the magnetic circuit 9 for adjusting the position of the objective lens 3 in the focusing direction and the tracking direction is arranged outside the window 8d. It becomes necessary to provide a gap L1 between the lower surface of 8b and the upper surface of the yoke 10 forming the magnetic circuit 9, and the distance L2 between the lower shell 8b and the lower surface of the magnetic circuit 9 becomes large, which reduces the thickness of the optical pickup device 4. It was an obstacle to miniaturization and miniaturization.

In view of the above-mentioned problems, it is an object of the present invention to provide a cartridge type optical disk device having a structure that can be made thinner and smaller.

[0006]

In order to achieve the above object, the present invention is characterized in that a magnetic circuit of an objective lens driving device is arranged in a window region of a lower shell of an optical disk. When such a structure is adopted, in order to prevent demagnetization of the optical disc, it is preferable to magnetically short-circuit both ends of the yoke forming the magnetic circuit of the drive device of the objective lens on the optical disc side with a magnetic material.

Further, according to the present invention, by forming both end portions in the tracking direction of the disk facing portion of the lens holder of the objective lens into inclined surfaces, the outermost circumference of the window of the lower shell,
This prevents the lens holder from colliding with the innermost edge and prevents the vertical width of the lens holder from increasing. Further, in the case where such inclined surfaces are formed on both end surfaces of the lens holder in the tracking direction, the magnetic circuit of the drive device of the objective lens is arranged in the window region of the lower shell of the optical disc, and the lower shell of the lens holder of the objective lens is arranged. More preferably, the portion of the window facing the side edge of the window is also formed as an inclined surface.

[0008]

By arranging the magnetic circuit of the driving device for the objective lens in the window of the lower shell, the dimension between the lower surface of the magnetic circuit of the driving device and the lower surface of the lower shell can be reduced, and thinning can be achieved. Further, the lens holder can be formed in a thin shape by forming both end portions in the radial direction of the disk facing surface portion of the lens holder of the objective lens into inclined surfaces.

[0009]

1 is a longitudinal sectional view showing an embodiment of an optical disk device according to the present invention, and FIG. 2 is a perspective view thereof. In FIGS. 1 and 2, reference numeral 11 denotes a base made of resin or the like, and a U-shaped yoke 10 and a reflection mirror 20 which form a magnetic circuit for driving the objective lens 3 are fixed to the base 11. Permanent magnets 12 are fixed to the facing surfaces of the yoke 10, respectively, and are magnetized in the left-right direction in the drawing as shown in FIG. A support 15 made of resin is fixed to the end of the base 11 with screws 16, and the support 15 and the lens holder 1
3 and 4 are connected by four wire springs 14. These wire-shaped springs 14 have their roots penetrated through the support 15 and the ends of the springs 14 are fixed by solder 17 to the printed circuit board 15a fixed to the support 15 by adhesion or the like. The solder is fixed to the printed board 13e fixed to both sides of the lens holder 13 by adhesion or the like. The lens holder 13 has the objective lens 3 attached to one end thereof and the other portion formed as a frame 13a, and the yoke 10 having the permanent magnet 12 fixed therein is inserted into the frame 13a so as to be relatively movable. is there. That is, as shown in the perspective view of FIG. 3, the focusing coil 18 is formed in a rectangular shape, a pair of tracking coils 19 is fixed to one surface thereof, and one permanent magnet 12 and one pillar portion of the yoke 10 to which the permanent magnet 12 is fixed. The focusing coil 18 is inserted and fixed in the frame 13a so that the focusing coil 18 surrounds 10a at a predetermined interval. As shown in FIG. 3, the portion of the focusing coil 18 to which the tracking coil 19 is fixed is inserted between the pair of permanent magnets 12, 12.

The magnetic circuit 9 of the drive device for the objective lens 3
As shown in FIG. 3, when a current indicated by an arrow i1 is passed through the focusing coil 18, the magnetic flux φ generated between the permanent magnets 12 and 12 interlinks with the coil through which the current flows, so that the focusing coil 18, That is, the lens holder 13 is biased in the direction of approaching the optical disk as shown by the arrow F1, and the lens holder 13 stands still when it balances with the elasticity of the wire spring 14. When the direction of the electric current is reversed, the lens holder 13 is urged in the direction away from the optical disc 1. When a current i2 is applied to the vertical portions a, a of the pair of tracking coils 19, the lens holder 13 receives a force in the direction of arrow F2 (tracking direction = optical disc radial direction) and reverses the current direction. The directions of power are opposite. The tracking coil 19 is arranged in a region deviating from the facing region between the permanent magnets 12, 12 so that the magnetic flux linkage amount of the portions b on both sides thereof is reduced.

In the present invention, as shown in FIG. 1, the magnetic circuit 9 of the drive device for the objective lens 3 is arranged in the window 8d of the lower shell 8b together with the objective lens 3. By arranging the magnetic circuit 9 in the region of the window 8d in this way, as shown in FIG. 4B, the dimension L10 from the lower surface of the lower shell 8b to the lower surface of the magnetic circuit 9 can be reduced, It can be made thinner and smaller. In this case, in order to prevent the magnetic recording surface of the optical disk 1 from being demagnetized by the magnetic field generated by the permanent magnet 12, a short-circuit member 21 having a high magnetic permeability such as iron is magnetically short-circuited between the tips of the yoke 10.

Further, as shown in FIG. 2, the lens holder 1
By forming both end portions 13b in the tracking direction of 3 on the inclined surfaces, the thickness of the lens holder 13 can be reduced. This will be described with reference to FIGS. Figure 5
As shown in (A), the lens holder 13 needs the width L5 of the magnetic circuit 9 (yoke 10) in order to drive the lens holder 13 in the focus direction and the tracking direction. The mechanical allowance for moving to, i.e., the gap (L6-L5) between the width in the frame portion 13a and the yoke 10 is required to be an arbitrary size, and the width of the frame 13a of the lens holder 13 is also required. Since it is necessary to secure the width, a width L7 that is considerably larger than the diameter of the objective lens 3 is required as a whole. In the lens holder 13 which requires such a width L7, if the both ends of the lens holder 13 in the radial direction of the optical disc are formed in a square shape as in the conventional case, the objective lens 3 is placed on the innermost or outermost side of the optical disc 1. When the objective lens 3 is driven in the focus direction in the state of being moved to, the lens holder 13 does not enter the window 8d and collides with the lower surface of the lower shell 8b. This occurs because the distance L4 between the upper portion of the lens holder 13 and the lower surface of the lower shell 8b is smaller than the movement amount in the upward focus direction as shown in FIG. 5 (A). If it is increased as indicated by L8, the distance L9 from the lower surface of the lower shell 8b to the lower surface of the magnetic circuit 9 becomes large (when the work distance of the objective lens 3 is constant).

On the other hand, in this embodiment, as shown in FIG. 6, since the side surface 13b of the lens holder 13 is inclined, the maximum strength of the window 8d as described above is maintained without impairing the strength of the lens holder 13. It is possible to reduce the thickness of the lens holder 13 while keeping the distance between the upper and lower sides of the inner peripheral side or the outermost peripheral side edge d and the lens holder 13 at a large distance L8 as in FIG. 5B. As a result, lower shell 8b
It is possible to reduce the total thickness L10 from the lower surface to the lower surface of the magnetic circuit 9.

For the same reason, FIG. 1 and FIG. 4 (B)
As shown in, by forming a portion 13c facing the side edge e of the window 8d of the lower shell 8b of the lens holder 13 on an inclined surface, the thickness L10 is reduced for the same reason,
It can be made thinner and smaller.

The magnetic circuit 9 in the above-mentioned embodiment is used.
It is needless to say that the configuration, the supporting structure of the lens holder 13 and the like are merely examples and can be variously modified.

[0016]

According to the present invention, in the cartridge type optical disk device, the magnetic circuit of the driving device for the objective lens is arranged in the window region of the lower shell, so that the optical pickup device can be made thin and compact. it can.

According to the second aspect, in addition to the effect of the first aspect, a magnetic material is magnetically short-circuited between both ends of the yoke of the magnetic circuit of the objective lens driving device on the side of the optical disc. However, there is no possibility that the magnetic recording surface of the optical disk will be demagnetized despite the proximity of

According to the third aspect, since both ends in the tracking direction of the disk facing surface of the lens holder of the objective lens are formed as inclined surfaces, the strength of the lens holder and the mechanical strength when moving in the focusing direction and the tracking direction. It is possible to achieve thinning and miniaturization while securing a margin.

According to claim 4, the magnetic circuit of the objective lens driving device is arranged in the window region of the lower shell of the optical disk, and the portion of the lens holder of the objective lens facing the side edge of the window of the lower shell is an inclined surface. Since it is formed, it can be made thinner and more compact.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of an optical disk device according to the present invention.

FIG. 2 is a perspective view of the present embodiment.

FIG. 3 is a perspective view illustrating a magnetic circuit of the objective lens driving device of the present embodiment.

FIGS. 4A and 4B are dimensional relationship diagrams of respective parts in the conventional example and the present example when the optical disk device is viewed in the tracking direction.

5A and 5B are dimensional relationship diagrams of respective parts at the outermost circumference or the innermost circumference of the disk in the conventional example and the comparative example, respectively.

FIG. 6 is a dimensional relationship diagram of each part in the present embodiment.

7A is a configuration diagram showing a cartridge type optical disc device, and FIG. 7B is a perspective view showing a schematic configuration of an optical disc and a cartridge.

[Explanation of symbols]

 1 Optical Disc 3 Objective Lens 9 Magnetic Circuit 10 Yoke 11 Base 12 Permanent Magnet 13 Lens Holder 14 Wire Spring 15 Support 18 Focusing Coil 19 Tracking Coil 20 Reflecting Mirror 21 Short-Circuiting Member

Claims (4)

[Claims] 1. An optical disc device using a cartridge type optical disc as a medium, wherein a magnetic circuit of an objective lens driving device is arranged in a window region of a lower shell of the optical disc. 2. The optical disk device according to claim 1, wherein a magnetic material is magnetically short-circuited between both ends of a yoke forming a magnetic circuit of an objective lens driving device on the optical disk side. 3. An optical disc device using a cartridge type optical disc as a medium, wherein both end portions of a lens holder of an objective lens in a tracking direction of a disc facing surface portion are formed as inclined surfaces. 4. The magnetic circuit of the objective lens driving device is arranged in the window region of the lower shell of the optical disc, and the portion of the lens holder of the objective lens facing the side edge of the lower shell window is an inclined surface. An optical disk device characterized by being formed.