JPS60625A - Optical disc device - Google Patents

Abstract

PURPOSE:To obtain an optical disc device possible for high speed accessing by decreasing remarkably a mass added to a radial direction moving means in the total mass of a focus lens moving means. CONSTITUTION:A focus lens 34 is fixed to a moving piece 35 of the focus lens moving means and conducts focusing vertically by a relative force with a stator 36 of the focus lens moving means fixed to a chassis 33. The moving mass of the radial movement is decreased remarkably by fitting respectively a magnetic circuit and the 2nd optical system having a large mass of the focus lens moving means to the chassis 33 and the tracking and the track accessing are realized by one actuator (radial moving means) by allowing the mechanical resonance frequency harmful to the tracking servo to be increased easily to a frequency without a problem and the high speed access servo is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical disc device for recording signals on a disc using laser beams or for reproducing signals from the disc.

Conventional Structure and Its Problems FIG. 1 is a diagram showing the structure of a conventional optical disc device. In the figure, an optical disc 1 is rotationally driven by a motor 2 fixed to a chassis 3. The optical disc 1 contains concentric or spiral optical information trunks, on which signal information can be recorded or reproduced by means of optical spots. A linear motor including a movable element 8 and a stator 9 is configured to move an optical system including a focus lens 4 in the radial direction of the optical disc 1 in order to apply a light spot to a desired information track. A stator 9 of the linear motor is fixed to the chassis 3. The optical system is composed of an optical block 7 including a light emitting element, a light receiving element, etc., a mirror 6, and a focus lens 4, and takes an optical path shown by a broken line in the figure. Focusing of the light beam is performed by vertically moving the focus lens 4 using a focus actuator 5 fixed to a movable element 8.

FIG. 2 is a diagram showing an example of a conventional focus actuator 6, which is of a type generally called a voice coil type. In this method, a focus lens supported by a damper 26 is moved up and down by a coil 24 inserted into a gap in a magnetic circuit made up of a permanent magnet 23 and a magnetic yoke 22.

Next, referring to FIG. 1, tracking of a light spot with respect to an information track will be explained. Tracking is performed by moving the light spot in the radial direction of the optical disk, so in principle 11. This can be done by the linear motor. However, in general, the movable mass of the entire optical system including the focus lens actuator 5 is quite large, requiring a large output from the linear motor, and the structure is likely to cause mechanical resonance that is harmful to the tracking servo. , a method is adopted in which a tracking actuator is separately provided to move only the focus lens 4 or mirror 6 for tracking.

It is clear from the above explanation that in the configuration of a conventional optical disk device, the movable mass in the radial direction for accessing a desired information track is an order of magnitude larger than the movable mass of the magnetic head in a conventional magnetic disk device. becomes larger. Therefore, it has not been possible to achieve high-speed access operations like the conventional Winchester magnetic disk drive in an optical disk drive.

OBJECTS OF THE INVENTION An object of the present invention is to provide an optical disk device that allows high-speed access by significantly reducing the radially movable mass of the track access reservoir.

Composition of the Invention The optical disc device of the present invention comprises an optical disc, a rotational drive means for rotating the optical disc, a shear 7 for fixing the rotational drive means, a first optical system including a focus lens, and a first optical system including a focus lens. a focus lens moving means for moving the lens in a direction perpendicular to the surface of the optical disk; a radial direction moving means for moving the optical system with the force 1 in an approximately radial direction of the optical disk; and a light beam directed toward the focus lens. The second optical system is configured to include a second optical system that transmits and receives the focus lens, and of a coil and a magnetic body that generate a driving force for the focus lens moving means, one is fixed to the focus lens and the other is fixed to the seven beams, This makes it possible to significantly reduce the mass added to the radial moving means out of the total mass of the focus lens moving means, thereby facilitating high-speed track access.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 shows a configuration diagram of an optical disc device according to an embodiment of the present invention. In FIG. 3, an optical disk 31 is rotated by a rotary drive means 3 fixed to a chassis 33, such as a motor. The focus lens 34 and mirror 38 constituting the first optical system are attached to a mover 39 of the radial drive means, and the optical system is driven by mutual force with the stator 4o of the radial drive means fixed to the chassis 34. Trunk access and tracking to the information trunk of the disk 31 is performed. The first optical system includes a second optical system composed of a light emitting element, a light receiving element, a lens, etc.
The optical system 37 transmits and receives parallel light. The second optical system 37 is fixed to the chassis 33. Focus lens 34
is fixed to the mover 35 of the focus lens moving means, and the focus lens mr fixed to the chassis 33 is
Focusing is performed in the vertical direction by the relative force of the th means with the stator 36.

FIG. 4 is a sectional view of essential parts showing details of the first optical system and focus lens drive means in FIG. 3. In FIG. 4, the focus lens 34 includes a coil 44 and a lens barrel 4.
1, and the lens barrel 41 is supported by a damper 42 with respect to a frame 43. A mirror 38 is fixed to a frame 43, and the frame 43 is fixed to a movable element 39 of the radial moving means shown in FIG. coil 4
4 is inserted into the gap of a magnetic circuit composed of a magnetic yoke 46 and a permanent magnet 46, and the magnetic circuit is fixed to the chassis 33 shown in FIG. As is clear from the figure, by energizing the coil 44, the focus lens 34 can be moved up and down.

As described above, according to this embodiment, the movable mass for radial movement is significantly reduced by adding the magnetic circuit and the second optical system, which have large masses among the focus lens moving means, to the chassis 33. This makes it easier to increase the mechanical resonance frequency, which is the title of the tracking servo, to a problematic range, making it possible to realize tracking and trunk access with the same actuator (radial movement means), and also enables high-speed accessing Bo is possible.

Next, other embodiments of the present invention will be described with reference to the drawings.

FIG. 6 is a diagram showing the configuration of a swing arm type optical disc device in which the present invention is implemented.

In FIG. 5, the optical disk 51 is rotated by a motor (not shown) fixed to a chassis 64.

In this case, the radial movement means are the rotor 66 and the shaft 61.
．． It is a rotary motor consisting of a stator 62 and a rotor 65.
A parallel spring composed of plate springs 67a1 and 57b is attached to the arm 56 via an arm 56, and a focus lens 62 and a coil 54 are fixed to the tips of the parallel springs 67a and 57b via a member 53. . The coil 64 is inserted into a gap in a magnetic circuit made up of a magnetic yoke 65 and a permanent magnet 66. The parallel light emitted from the second optical system 63 passes through the center of the shaft 61 of the rotary motor, and is guided to the focus lens 52 by the mirror 58 fixed to the arm 56 by the mirror 60 and mirror mounting member 69. has been done. In addition, L in FIG. 5 indicates an optical path, and M indicates a rotation axis.

6 and 7 are perspective views of the magnetic circuit and coil in FIG. 5, respectively. In FIG. 6, the magnetic circuit has an arc-shaped gap centered on the rotation axis of the radial moving means. Further, in FIG. 7, the side of the coil 54 inserted into the magnetic gap is similarly finished in an arc shape, realizing an efficient magnetic circuit with a short gap.

As is clear from the above embodiments, the present invention is also applicable to a swing arm system.

In the above embodiments, the focus lens moving means is of a movable coil type, but it goes without saying that it can also be realized with a moving magnet type or a movable iron piece type.

Effects of the Invention As is clear from the above explanation, the unexploded F3F4 has a radially movable mass involved in tracking and track access by fixing one of the coil and magnetic material that generates the driving force of the focus lens moving means to the chassis. This has the advantageous effect that it is possible to reduce the amount of time required to access the optical disc, thereby realizing an optical disc device with faster access. In addition, in the conventional method, it is necessary for the radial movement means to absorb the reaction to the movement of the mass of the focus lens movement means in the focus direction, and there is a limit to the reduction of structural rigidity and radially movable mass. Since the reaction force is directly absorbed by the large-mass chassis, there is also the effect that anti-resonance problems in the focusing mechanism are less likely to occur.

Furthermore, by configuring the focus lens moving means with a moving coil type and fixing the magnetic circuit containing a permanent magnet to the chassis, restrictions on the size and mass of the magnetic circuit are relaxed, so it is not necessary to use expensive rare earth magnets as in the past. This has the effect that a sufficient gap magnetic flux density can be obtained using an inexpensive ferrite magnet without using a ferrite magnet.

Furthermore, by fixing the second optical system to the chassis,
Furthermore, the amount of movement can be reduced, and as a result,
The load on the radial moving means is only the focus lens Danhardt mirror and the movable element (for example, a coil) of the focus lens drive means, which can actually be comprised from 1 to 2 gr. Therefore, there is an effect that high-speed access operations comparable to those of conventional magnetic disk devices can be realized.

Furthermore, by using a swing arm type as the radial moving means, the bearing structure, which is a feature of the swing arm type, can be simplified, and the effective bearing friction and effective movable mass υ of the focus lens position calculation can be reduced. It has the effect of greatly enhancing the basic effects of.

Furthermore, in the swing arm type focus lens moving means, by making the coil or magnetic circuit gap match the arc shape of the swing radius, an efficient magnetic circuit can be achieved.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a conventional optical disc device, FIG. 2 is a sectional view of an example of a conventional focus lens moving means, and FIG. 3 is a configuration diagram of an optical disc device according to embodiments of the present invention.
4 is a detailed sectional view of the main part of FIG. 3, FIG. 6 is a configuration diagram of an optical disk device according to another embodiment of the present invention, FIG. 6 is a perspective view of the magnetic circuit of FIG. FIG. 7 is a perspective view of the coil of FIG. 5. 31... Optical disk, 32... Rotation drive means, 33... Chassis, 34...
・Focus lens, 36...B'' mover of focus lens moving means, 36...Stator of focus lens moving means, 37...Second optical system, 39・・・・・・Mover of radial direction moving means, 4o...
...Stator of radial movement means. Name of agent: Patent attorney Toshio Nakao and 1 other person Shima 1
Figure 2 Figure 5 Figure 3 40 Figure 4 Figure 5 Figure 6 Figure 7 Figure 1

Claims (1)

[Scope of Claims] (1) An optical disk, a rotational drive means for rotating the optical disk, a chassis for fixing the rotational drive means, a first optical system including a focus lens, and a first optical system including a focus lens; Forgus lens moving means for moving in a direction perpendicular to the surface of the optical disk; radial moving means for moving the first optical system in a generally radial direction of the optical disk; and sending and receiving a light beam to and from the focus lens. An optical disk device configured to include a second optical system for moving the focus lens, and of a coil and a magnetic body that generate a driving force for the focus lens moving means, one of which is fixed to the focus lens and the other fixed to the chassis. (2) The optical disk device according to claim (1), wherein the magnetic body is constituted by a magnetic circuit including a permanent magnet, and the magnetic circuit is fixed to the chassis. (3) The optical disc device according to claim (1), characterized in that the second optical system is fixed to the shear 7. (41) The optical disc apparatus according to claim (1), wherein the radial moving means is configured to linearly move the focus lens. The optical disk device according to claim 1, wherein the optical disc device is configured to move the lens in an arc shape.(6) The optical disc device according to claim 1, wherein the magnetic circuit has an arc shape gap. The optical disk device according to claim (3) or (4). (7) The magnetic circuit gear knob insertion portion of the coil is in an arc shape.
).