JPH02187946A - Magneto-optical disk device - Google Patents

Abstract

PURPOSE:To enhance the mechanical rigidity of a coil bobbin, to improve frequency characteristic and to operate a movable part at high speed by using a ceramic material for a guide rail and a guide ball. CONSTITUTION:A voice coil motor 4 is constituted of a magnetic closed circuit consisting of a center pole 8, yokes 9, 10 and permanent magnets 11, 12, and a coil bobbin 5 consisting of a ceramics material. To left and right side face diameters of the bobbin 5, linear guides 14, 15 of a ceramics material having a V-groove are fixed, and supported by linear guides 20, 21 of the ceramic material having a V-groove supported and fixed by supporting plates 18, 19 through balls 16, 17 of the ceramic material. In this state, a forward and backward linear motion is executed in the A direction by the direction of a current flowing to a coil 13, and a beam 22 from an input/output optical head 1 passes through a focus actuator 3 and an objective lens 2 and converged to the medium 6 of a magneto-optical disk 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an information file device, and particularly to a magneto-optical disk device capable of writing, reading, erasing, rewriting, etc. of information.

(Prior Art) Magneto-optical disk devices are becoming mainstream as large-capacity file devices. However, compared to magnetic disks, which are currently the mainstream for computers and file devices, they have problems such as long access times and slow data transfer speeds. For this reason, it is desired that the performance of the magneto-optical disk device be improved, such as faster access and faster data transfer speed.

Conventionally, these magneto-optical disk drives have a structure in which the input/output optical head and focus actuator are separated in order to increase access speed and data transfer speed.
The focus actuator is driven by a cylindrical or rectangular voice coil motor, and the voice coil motor uses plastic for the coil bobbin and magnetic material such as hardened steel for the guide rail and guide pole.

(Problems to be Solved by the Invention) However, in the above-mentioned voice coil motor, since a plastic material was used for the coil bobbin, the mechanical rigidity was low, which adversely affected the frequency characteristics. In addition, because magnetic materials such as hardened steel were used for the guide rails and guide poles, leakage magnetic flux from the magnetic circuit attracted the moving parts, creating load resistance during movement, which had a negative impact on high-speed access of the carriage. .

(Means for Solving the Problem) The magneto-optical disk device of the present invention includes an input/output device including a semiconductor laser and a beam detector for writing, reading, erasing, etc. information on a rotating magneto-optical disk medium surface. An optical head is fixed to a substrate, and an objective lens and a focus actuator for imaging the emitted light or incident light of the input/output optical head as a spot on the magneto-optical disk medium surface are coupled to a linear actuator for track positioning, and the linear In a magneto-optical disk device using a voice coil motor as an actuator, the voice coil motor includes a coil bobbin, a guide rail for guiding the coil bobbin, and a guide ball made of ceramic material.

(Function) By using ceramic materials for the coil bobbin and the guide rail and guide ball that guide the coil bobbin as in the present invention, the mechanical rigidity of the coil bobbin is increased, the frequency characteristics can be greatly improved, and it is not affected by eddy currents. . Furthermore, since the guide rail and guide ball are not affected by leakage magnetic flux from the magnetic circuit, load resistance during movement of the movable part is eliminated, allowing high-speed operation of the movable part.

(Example) An example of the present invention will be described in detail below with reference to the drawings.

1, 2, and 3 are diagrams for explaining one embodiment of the present invention, in which FIG. 1 is a partially exploded perspective view showing the configuration of the magneto-optical disk device of the present invention, and FIG. The figure is a partially exploded perspective view of the linear actuator mechanism, and FIG. 3 is a sectional view of the center part of FIG. 2.

First, the schematic configuration of the apparatus will be explained with reference to FIG.

As shown in the figure, this magneto-optical disk device has a configuration in which an input/output optical head 1 and a focus actuator 3 that drives an objective lens 2 are separated. It is supported by the coil bobbin 5 of the voice coil motor 4 and moves linearly. A magneto-optical disk 7 having a recording medium 6 enclosed therein is installed above the focus actuator 3 so as to rotate at a constant rate.

Next, the present invention will be explained in detail with reference to FIGS. 2 and 3.

The voice coil motor 4 is mainly composed of a magnetic closed circuit composed of a center pole 8 made of magnetic material, yokes 9 and 10, and permanent magnets 11 and 12, and a coil bobbin 5 made of ceramic material (silicon nitride in this embodiment). be done. In other words, the cylindrical diameter center pole 8 in the center and the fan-shaped yokes 9 and 10 fixed so as to surround it are connected at the rear end surface, and the inner surfaces of the yokes 9 and 1o are each magnetized in the thickness direction. Fan-shaped permanent magnets 11 and 12 are closely fixed to yokes 9 and 10 so that their poles face toward the center pole 8 side. A suitable gap is provided between the permanent magnets 11, 12 and the center ball 8, and the coil bobbin 5 is installed so as to be inserted into this gap. A coil 13 in which enameled wire is wound a plurality of times is fixed to the rear part of the coil bobbin 5. Linear guides 14 and 15 made of ceramic material (silicon nitride in this embodiment) having V-grooves are fixed to the outer diameter of the left and right sides of the coil bobbin 5, and poles 16 and 17 made of ceramic material (silicon nitride in this embodiment) are fixed. They are supported by linear guides 20 and 21 made of ceramic material (silicon nitride in this embodiment) and having V-grooves that are supported and fixed to support plates 18 and 19 via. A focus actuator 3 having an objective lens 2 is installed at the tip of the coil bobbin 5. Coil bobbin 5, coil 13, and linear guides 14, 15 do not contact center ball 8 and permanent magnets 11, 12.

Next, the operation will be explained.

Permanent magnet 11.12 installed inside the yoke 9.10
Since both have their N poles facing the center ball 8 side,
The magnetic flux emitted from the N pole is distributed between the center ball 8 and the yoke 9.
, lO'fi-, and then returns to the south pole. In other words, since magnetic flux is always emitted perpendicularly toward the center of the center ball in the air gap between the permanent magnets 11 and 12 and the center ball 8, when a current is applied to the coil 13, Fleming's left hand is affected by the direction of current flow. It moves in a straight line back and forth in the direction of arrow A based on the law. The moving distance of the focus actuator 3 is the width of the recording medium 6 of the magneto-optical disk 7.

Next, the beam path will be explained.

Beam 22 (optical axis) emitted from the input/output optical head 1
goes straight and is fixed to the tip of the coil bobbin 5 inside the focus actuator 3 (not shown)
The beam is raised by the beam, passes through the objective lens 2, and converges on the recording medium 6 of the magneto-optical disk 7. Next, the return beam 22 reflected by the recording medium 6 is incident on the input/output optical head through the previously mentioned reverse path.

(Effects of the Invention) As described above, according to the present invention, 1. Since the coil bobbin is made of ceramics, the mechanical strength is approximately 10 times that of a plastic bobbin, and the rigidity is greatly increased, so that the frequency characteristics are extremely improved. In the example, the primary resonance is 30 Hz and the secondary resonance is 10 KHz, and the servo band during control is significantly widened, making control extremely easy. In addition, it had good electrical insulation when the coil was wound, and was extremely effective in preventing eddy currents when the coil bobbin moved through the magnetic circuit. In addition, by using ceramics for the linear guides and guide balls on the fixed and movable parts, they are no longer affected by magnetic flux leakage from the magnetic circuit, so when the linear guides on the movable part move, there is no load resistance and the movement is extremely smooth. It works, and the power consumption of the coil has also decreased. Also, during assembly, there is no effect of leakage magnetic flux from the magnetic circuit, so adjustments can be made with extremely high precision.

From plastic coil bobbins to ceramics,
By changing the linear guide from hardened steel to ceramics, the coil bobbin has become about 1.5 times heavier, and the linear guide has become about 1/2 lighter, but the total weight of the moving parts has not been reduced. Ta.

As mentioned above, the present invention has many advantages, and it is possible to realize faster access, lower power consumption, etc. while taking advantage of these features.

[Brief explanation of the drawing]

FIG. 1 is a partially exploded perspective view showing the overall configuration of the magneto-optical disk device of the present invention, FIG. 2 is a partially exploded perspective view of the linear actuator mechanism, and FIG. 3 is a sectional view of the center of FIG. 2. be.

Claims (1)

[Claims] An input/output optical head including a semiconductor laser and a beam detector for writing, reading, and erasing information on the rotating magneto-optical disk medium surface is fixed to the substrate, and the input/output optical head is used to detect the emitted or incident light from the input/output optical head. In a magneto-optical disk device having a structure in which an objective lens and a focus actuator for forming an image as a spot on a magneto-optical disk medium surface are coupled to a linear actuator for track positioning, and a voice coil motor is used for the linear actuator, the voice coil A magneto-optical disk device characterized in that the motor includes a coil bobbin, a guide rail for guiding the coil bobbin, and a guide ball made of ceramic material.