JPH04355237A - Magneto-optical disk device - Google Patents

Abstract

PURPOSE:To allow the prevention of the contact of a magnetic head and a magneto-optical disk so as to protect the magnetic head and the magneto-optical disk against a failure. CONSTITUTION:The magneto-optical disk device is provided with leaf springs 13a, 13b as magnetic head displacing means for displacing the magnetic head 14 up to the position where the head does not come into contact with the magneto-optical disk 1 during de-energization.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical disk device that displaces a magnetic head to a position where it does not come into contact with a magneto-optical disk when power is not applied.

0002

2. Description of the Related Art In recent years, magneto-optical disk devices have been put into practical use as memories capable of recording, reproducing, and erasing information. Magneto-optical disks use a perpendicularly magnetized film that is perpendicular to the film surface relative to the direction of magnetization as a recording medium, and the temperature of the recording medium is raised by irradiating it with laser light, reducing the coercive force. By applying an external magnetic field to the perpendicularly magnetized film, the direction of magnetization is made to match the direction of the external magnetic field, thereby recording information.

[0003] When rewriting information on a recorded magneto-optical disk, it is also possible to record new information directly.
An example of a method that can achieve so-called overwriting is a magnetic field modulation method in which the direction of an external magnetic field is reversed depending on the information to be recorded while irradiating a laser beam with a constant intensity. A magnetic head that supplies an external magnetic field needs to have low inductance in order to increase the switching speed of the direction of the external magnetic field and improve the transfer rate. It is necessary to bring the head close to the magneto-optical disk. Furthermore, with the miniaturization of magneto-optical disk devices, lower power consumption is required. In order to achieve low power consumption, the amount of current flowing through the magnetic head must be kept low, and as a result, the strength of the generated magnetic field will decrease, so it is not possible to place the magnetic head close to the magneto-optical disk. is necessary.

[0004] Magnetic heads include, for example, fixed magnetic heads that are fixed to the housing of an optical head and supply a magnetic field onto a light beam spot, and position control heads that cause the position of the magnetic head to follow the movement of a recording medium. A tracking type magnetic head equipped with means has been proposed.

However, when a resin such as polycarbonate is used as a substrate material for a magneto-optical disk, large warping may occur on the surface of the substrate, and when the magneto-optical disk is rotated by a spindle motor, the substrate warps. appears as a wobble.

Therefore, when the fixed magnetic head is brought too close to the magneto-optical disk, the magnetic head and the rotating magneto-optical disk come into contact due to the influence of the surface runout of the magneto-optical disk, causing the magnetic head and the optical disk to come into contact with each other. There is a risk of damaging the magnetic disk. On the other hand, if the magnetic head is not brought close enough to the magneto-optical disk, the distance between the magnetic head and the magneto-optical disk changes due to surface runout of the magneto-optical disk, and the strength of the magnetic field generated by the magnetic head increases to the surface of the magneto-optical disk. As a result, stable recording characteristics cannot be obtained.

[0007]

[Problems to be Solved by the Invention] However, as described above, when the magnetic head and the magneto-optical disk are held at a very small distance, if the power of the device is suddenly turned off and the power is turned off, the magnetic head may come into contact with the magneto-optical disk. In particular, when a magneto-optical disk device is transported with a magneto-optical disk inside it, or when a strong impact force is applied to the magneto-optical disk device due to other external factors, the magnetic head may come into contact with the magneto-optical disk. Problems have arisen in which the magnetic head is damaged and the magneto-optical disk is scratched.

[0008]

Means for Solving the Problems In order to solve the above problems, the magneto-optical disk device of the present invention includes a magnetic head that supplies a magnetic field to a recording medium, and when energized, the magnetic head maintains a predetermined distance from the recording medium. A magneto-optical disk device that performs positional control so as to maintain the recording medium is characterized in that it includes a magnetic head displacement means for displacing the magnetic head above the recording medium when the magnetic head is not energized.

[0009] For example, the magnetic head displacement means may include a plate spring having restoring force.

0010

[Operation] With the above configuration, the position of the magnetic head is controlled so as to maintain a certain distance from the recording medium during normal operation, but when the magnetic head is not energized, the magnetic head is moved above the recording medium by the magnetic head displacement means. Displaced. At this time, if the amount of displacement of the magnetic head is set in consideration of surface runout due to warping of the recording medium, etc., the magnetic head and the recording medium will not come into contact with each other. For example, if a magnetic head displacing means having a restoring force, such as a plate spring, is used, the restoring force causes the magnetic head to move away from the recording medium by the set displacement amount when the magnetic head is not energized.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

As shown in FIG. 5, the magneto-optical disk device of this embodiment includes an optical pickup 26 that irradiates a magneto-optical disk (recording medium) 1 with a laser beam and captures reflected light from the magneto-optical disk 1. , a magnetic head 14 that applies a constant magnetic field to the magneto-optical disk 1, and a spindle motor (not shown) that rotationally drives the magneto-optical disk 1. The optical pickup 26 includes a laser light source 5,
A laser light source drive circuit 3 that drives this laser light source 5;
An optical system 6 composed of a collimating lens, a shaping prism, a polarizing beam splitter, etc., a photodetector 8 that detects the light incident from the optical system 6, and a magneto-optical disk 1.
It has an objective lens 7 for condensing the laser beam.

Further, the objective lens 7 is held by an objective lens actuator 10 driven by an objective lens actuator drive circuit 9, and the focal position of the laser beam spot is controlled by this objective lens actuator 10. ing. Further, the optical pickup 26 is provided so as to be movable in the radial direction of the magneto-optical disk 1 by a feeding mechanism (not shown) equipped with a driving means such as a linear motor.

Furthermore, the objective lens holder 18 constituting the movable part of the objective lens actuator 10 is equipped with an LED (Light Emitting Diode) as a light source.
ode) 19 is attached to move integrally with the objective lens 7, and together with a photodetector 20 fixed at a position facing the LED 19, constitutes an objective lens position detection means 21. This photodetector 20 is, for example, a two-split photodetector or a PSD (Positive photodetector).
tion sensing device), etc.
This is a position detection element whose output signal changes depending on the position of the LED 19.

On the other hand, the magnetic head 14 is held in a magnetic head holder 15 which is a movable part of a magnetic head actuator 16 driven by a magnetic head actuator drive circuit 17, and the magnetic head 14 is held in a magnetic head holder 15 which is a movable part of a magnetic head actuator 16 driven by a magnetic head actuator drive circuit 17. Position control is performed accordingly.

Next, the magnetic head actuator 16
The configuration of the main parts will be explained based on FIGS. 2 and 3. A support arm 12 is attached to the optical pickup 26, and a yoke plate 11 is attached to the tip of the support arm 12.
One end is fixed. On the other hand, at the other end of the yoke plate 11, there is a
In FIG. 3, an outer vertical surface portion 11a extending upward)
- 11b is provided. Further, inside the outer vertical surface portions 11a, 11b, the outer vertical surface portions 11a, 11
Inner vertical surface portions 11c and 11d located parallel to b are provided. Magnets 28a and 28b are fixed along the inside of each of the outer vertical surface portions 11a and 11b, which are located on the outer side of the yoke plate 11 with the center thereof in between.

Further, magnetic head actuator coils 27a and 27b each having a cylindrical shape with a substantially rectangular cross section are attached to the recesses formed on both sides of the magnetic head holder 15. This magnetic head holder 1
5 is the inner vertical surface portion 11c and 11d of the yoke plate 11;
However, the magnetic head actuator coils 27a and 27b
The magnetic head holder 15 is located through the magnetic head holder 15.
A magnetic head 14 attached to the yoke plate 11 is disposed outside the yoke plate 11.

Further, a leaf spring support portion 11e projecting from the yoke plate 11 passes through the opening 15a of the magnetic head holder 15. In the opening 15a, a plate spring support part 15b having a slight step difference from the upper surface of the magnetic head holder 15 is formed at a position facing the plate spring support part 11e of the yoke plate 11. The plate spring 13a (magnetic head displacement means) is attached to the plate spring support portion 11e of the yoke plate 11.
and is fixed to the leaf spring support portion 15b of the magnetic head holder 15. Further, below this leaf spring 13a,
A plate spring 13b (magnetic head displacement means) located parallel to the plate spring 13a is fixed at a substantially central position of the plate spring support part 11e and below the plate spring support part 15b.

That is, the magnetic head holder 15 is
Leaf springs 13a and 13b fixed on one side to the yoke plate 11
Supported by When the magneto-optical disk device is not energized, the leaf springs 13a and 13b are slightly bent due to the weight of the magnetic head holder 15.
4 upwardly to a position where it does not come into contact with the magneto-optical disk 1.

Further, an LED 23 is attached to the magnetic head holder 15 as a light source. This LED2
A photodetector 24, which together with the LED 23 constitutes the magnetic head position detecting means 22, is fixed to a photodetector fixing portion 11f projecting from the yoke plate 11 at a position facing the photodetector 3. This photodetector 24 for detecting the position of the magnetic head includes:
Similar to the photodetector 20 for detecting the objective lens position, a two-segment photodetector, PSD, or the like is used.

Next, the operating state of the magneto-optical disk device having the above configuration will be explained based on FIG.

When the magneto-optical disk 1 is rotated by a spindle motor (not shown) and the input signal 2 is input to the laser light source drive circuit 3 and the magnetic head drive circuit 4, laser light is emitted from the laser light source 5. This laser beam passes through the optical system 6 and enters the objective lens 7, and the magneto-optical disk 1
The light is focused on the top.

As a result, information is recorded, reproduced, and erased on the magneto-optical disk 1. When recording or erasing information, the magnetic head drive circuit 4 drives the magnetic head while irradiating the laser beam. A magnetic field generating current is passed through a coil 25 wound around the magneto-optical disk 1, and a constant magnetic field is applied to the magneto-optical disk 1. Further, when the objective lens 7 irradiates the magneto-optical disk 1 with laser light as described above, it is moved in the radial direction of the magneto-optical disk 1 to a target track by a feeding operation of a feeding mechanism (not shown).

On the other hand, the reflected light from the magneto-optical disk 1 passes through the objective lens 7 again, enters the photodetector 8 via the deflection beam splitter in the optical system 6, and is focused at the photodetector 8. An error signal is detected. Further, this signal is sent from the photodetector 8 to the objective lens actuator drive circuit 9, and the signal is sent to the objective lens actuator drive circuit 9.
By driving, the focal position of the objective lens 7 is controlled.

The amount of displacement of the objective lens 7 due to this focus position control is detected by the objective lens position detection means 21, and this detection signal is guided to the magnetic head actuator drive circuit 17. Further, a detection signal from a magnetic head position detection means 22 for detecting the position of the magnetic head 14 is also input to the magnetic head actuator drive circuit 17 . Then, based on the output signal of the magnetic head actuator drive circuit 17, the magnetic head actuator 16 is driven so that the magnetic head 14 is displaced by approximately the same amount of displacement as the objective lens 7, and the position of the magnetic head 14 is controlled. be exposed.

During normal operation, the magnetic head actuator drive circuit 17 energizes the magnetic head actuator coils 27a and 27b, and the magnetic head 14 is positioned so as to maintain a very small distance from the magneto-optical disk at, for example, about 0.1 mm. controlled (see Figure 4). On the other hand, when the magnetic head actuator coils 27a and 27b are de-energized, that is, when they are not energized, the restoring force of the leaf springs 13a and 13b causes
The magnetic head holder 15 to which the magnetic head 14 is fixed is displaced upward. Therefore, the magnetic head 14
is displaced above the magneto-optical disk 1 to a position where it does not come into contact with the stationary magneto-optical disk.

As described above, in the magneto-optical disk device of the present embodiment, when switching from the energized state to the de-energized state, the magnetic head 14 uses the restoring force of the leaf springs 13a and 13b to move the magneto-optical disk. 1. On this occasion,
Since the amount of displacement of the magnetic head 14 is set in consideration of the surface runout of the magneto-optical disk 1, there is no possibility that the magneto-optical disk 1 and the magnetic head 14 will come into contact with each other during transportation or due to other external factors. Even when a strong impact force is applied to the magneto-optical disk device, the magnetic head 14 does not come into contact with the magneto-optical disk 1, and damage to the magnetic head 14 and the magneto-optical disk 1 can be prevented.

[0028]

As described above, the magneto-optical disk device of the present invention is equipped with a magnetic head displacement means for displacing the magnetic head above the recording medium when the magnetic head is not energized.

[0029] Therefore, the magnetic head and the magneto-optical disk do not come into contact with each other when the power is not applied, and it is possible to prevent damage to the magnetic head and the magneto-optical disk.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part of a magneto-optical disk device according to an embodiment of the present invention, showing the configuration of a magnetic head when power is not supplied.

FIG. 2 is a plan view of the magneto-optical disk device.

FIG. 3 is a side view of the magneto-optical disk device.

FIG. 4 is a cross-sectional view of a main part of the magneto-optical disk device showing the structure of the magnetic head when energized.

FIG. 5 is a schematic diagram showing the configuration of the magneto-optical disk device.

[Explanation of symbols]

1 Magneto-optical disk (recording medium) 13a, 13b
Leaf spring (magnetic head displacement means) 14 Magnetic head

Claims (1)

[Claims] 1. A magneto-optical disk device comprising a magnetic head that supplies a magnetic field to a recording medium, and controlling the position of the magnetic head so that it maintains a predetermined distance from the recording medium when energized, the magnetic head being controlled when not energized. A magneto-optical disk device comprising a magnetic head displacing means for displacing a magnetic head above a recording medium.