JPH08167193A - Disk recording reproducing device - Google Patents

Abstract

PURPOSE: To decrease the consumption of electric power, to miniaturize the device and to improve the stability of operation. CONSTITUTION: An electromagnetic coil 18 having a tapered top is fixed around an objective lens 5. When an electric current is applied on the electromagnetic coil 18, a magnetic field which concentrates near the recording point p where laser light 4 is focused is produced. Since a magnetic field is efficiently applied only on the recording point p by the small-size electromagnetic coil 18, the consumption of power can be decreased. The electromagnetic coil 18 can be vertically moved with the objective lens 5 by a focus controlling means so that the gap g between the electromagnetic coil 18 and the magneto-optical disk 2 can be always maintained const. Thus, the magnetic flux applied on the recording point p is always const. Further, since the electromagnetic coil 18 and the optical pickup 11 are disposed under the magneto-optical disk 2, the height of the whole device can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc recording / reproducing apparatus suitable for application to a rewritable magneto-optical disc or the like.

[0002]

2. Description of the Related Art In an optical disk capable of rewriting data, for example, a magneto-optical disk (MO), data rewriting is based on an optical modulation method. The optical modulation method is to record (write) data on a magneto-optical disk by modulating an excitation signal of a light emitting element such as a laser diode (not shown) provided in the optical pickup means.

In the optical modulation method, as shown in FIG. 7, information is recorded as upward or downward magnetization in the magneto-optical disk 2 which is a perpendicular magnetization film. During recording, the laser light 4 is used as a heat source as shown in FIG. In addition, the direction of perpendicular magnetization of the magneto-optical disk 2 is uniformly aligned upward. A laser beam 4 emitted from a laser diode (not shown) is condensed there by an objective lens 5 provided in the optical pickup unit 1 (FIG. 8), and irradiated onto a recording point p of the magneto-optical disk 2. When the temperature at the recording point p locally rises and reaches near the Curie temperature, the coercive force of the magneto-optical disk 2 decreases and the magneto-optical disk 2 generates the magnetic field in the same direction by the electromagnetic coil 3 as a static magnetic field generating means. The downward magnetic field reverses the magnetization.
Then, at the time of recording the data, the output of the laser beam 4 is changed (modulated) in accordance with the data, and the direction of the vertical magnetic field of the magneto-optical disk 2 is changed upward and downward depending on the location, so that the data is recorded.

At the time of erasing, as shown in FIG. 1B, if the magnetic field of the electromagnetic coil 3 is reversed and the laser beam 4 of the same output is irradiated, the direction of perpendicular magnetization is changed by the same principle as the recording operation. The data is erased by aligning upward and evenly. Further, as shown in FIG. 6C during reproduction, when the laser light 4 is incident, the deflecting surface of the reflected light 4b with respect to the incident light 4a rotates to the left or right depending on the direction of magnetization.
By detecting this rotation, information can be reproduced.

In a conventional optical modulation type disc recording / reproducing apparatus using such a principle, an electromagnetic coil 3 is arranged above the magneto-optical disc 2 and below the magneto-optical disc 2 as shown in FIG. An optical pickup unit 1 having an objective lens 5 is arranged. The optical pickup unit 1 is the support unit 2
It is fixed on one. The support portion 21 is slidably supported by a slide shaft 22, and the optical pickup portion 1 is movable along the radial direction of the magneto-optical disk 2. Since the magnetic field generated by the electromagnetic coil 3 must cover the entire recording area of the magneto-optical disk 2, the electromagnetic coil 3 has a length that covers the entire recording area in the radial direction of the magneto-optical disk 2. There is.

At the time of recording, erasing and reproducing, the magneto-optical disk 2 is rotationally driven and the optical pickup section 1 is moved in the radial direction of the magneto-optical disk 2 by an electromagnetic driving section (not shown) to follow the signal track. The laser light 4 is applied to the surface of the magneto-optical disk 2. The electromagnetic coil 3 generates a downward or upward magnetic field in accordance with the recording or erasing operation.

There is also an example in which a permanent magnet 6 is used instead of the electromagnetic coil 3 as shown in FIG. Like the electromagnetic coil 3, the permanent magnet 6 has a length along the radial direction of the magneto-optical disk 2 over the entire recording range, and is rotatably attached to the apparatus body. The magnet rotating coil 7 arranged above the permanent magnet 6 is controlled so as to change the direction of the magnetic field during the recording operation and the erasing operation. The direction of the static magnetic field with respect to the magneto-optical disk 2 can be changed between the recording operation and the erasing operation by the magnetic field generated by the magnet rotating coil 7 and the magnetic pole of the permanent magnet 6 acting to reverse the permanent magnet 6. it can.

Further, as shown in FIG. 10, when the magneto-optical disk 2 housed in the cartridge 25 is used, the surface of the magneto-optical disk 2 is exposed to the electromagnetic coil 3 and the objective lens 5, respectively. For this purpose, openings 27a and 27b are provided above and below the cartridge 25. The openings 27a and 27b are normally the shutter 26.
It is in a closed state by a and 26b. Then, at the time of operation, the shutters 26a and 26b are slid and opened by an appropriate lid opening means (not shown) to expose the upper and lower surfaces of the magneto-optical disk 2. Then, the electromagnetic coil 3 or the permanent magnet 6 descends and stands still at a position where the gap g with respect to the surface of the magneto-optical disk 2 becomes a predetermined value. Further, the objective lens 5 of the optical pickup unit 1 moves up to approach the magneto-optical disk 2, and recording and erasing are performed.

[0009]

By the way, in the conventional optical modulation type disk recording / reproducing apparatus, a relatively strong static magnetic field (for example, about 250 Oersted) is required when performing recording and erasing operations, and the generated static magnetic field is generated. Since the large-sized electromagnetic coil 3 whose magnetic field covers the entire recording range of the magneto-optical disk 2 is used, it causes increase in power consumption. Further, as shown in FIG. 8 or 9, since the electromagnetic coil 3 and the permanent magnet 6 are arranged above the magneto-optical disk 2, there is a problem that the height of the entire device becomes high.

Further, when the magneto-optical disk 2 housed in the cartridge 25 is used, the electromagnetic coil 3 or the permanent magnet 6 is moved to a predetermined position as shown in FIG. I needed to. Therefore, an error may occur in the position of the electromagnetic coil 3 or the permanent magnet 6 after the movement. In this case, the gap g between the electromagnetic coil 3 or the permanent magnet 6 and the magneto-optical disk 2 does not reach a predetermined distance, and the operating conditions at the time of recording and erasing change. Therefore, there has been a problem that the recording and erasing operations become unstable and the reliability of the recorded data becomes low. Further, the shutter 2 is also provided above the cartridge 25.
6a is provided, and a lid opening mechanism or the like for opening and closing the 6a is required, which causes a problem that the configuration of the apparatus becomes complicated.

Therefore, the present invention has solved the above-mentioned problems, and is capable of reducing power consumption, simplifying the configuration, and downsizing the apparatus, and recording / reproducing information in a stable recording / erasing operation. It proposes a device.

[0012]

In order to solve the above-mentioned problems, in the present invention, a pickup means having an objective lens for converging a laser beam modulated corresponding to data to be recorded on an optical disc is provided. A static magnetic field generating means for applying an auxiliary magnetic field to the disk, wherein a static magnetic field generating means is provided around the objective lens in a disk recording / reproducing apparatus in which the optical pickup means is arranged to face the optical disk. It is characterized by.

[0013]

As shown in FIG. 1, the actuator movable portion 17
A tapered electromagnetic coil 18 is wound and fixed on the outer circumference of the objective lens 5. When the electromagnetic coil 36 is energized, a magnetic field is generated such that the laser light 4 is concentrated near the recording point p where it is focused. Since the electromagnetic coil 18 moves up and down together with the actuator movable portion 17 and the objective lens 5 during focus adjustment, the electromagnetic coil 18 and the magneto-optical disk 2
The gap g between and is always kept constant. Therefore, the magnitude of the magnetic flux applied to the recording point p is always constant.

Further, since both the electromagnetic coil 18 and the optical pickup section 11 are arranged below the magneto-optical disk 2, the height of the entire apparatus can be reduced. Magneto-optical disk 2 housed in cartridge 25 (FIG. 10)
In the case of using, the mechanism for opening the shutter 26a (FIG. 10) on the upper side of the cartridge 25 is not required, so that the configuration of the entire apparatus can be simplified.

As shown in FIG. 2, the electromagnetic coil 18 moves in the radial direction of the magneto-optical disk 2 together with the optical pickup section 11, and the electromagnetic coil 18 is tapered so that the magnetic field is concentrated near the recording point p. To do. As described above, by efficiently applying the magnetic field only to the recording points with the small electromagnetic coil 18, the power consumption can be significantly reduced.

[0016]

Next, an embodiment in which the disk recording / reproducing apparatus according to the present invention is applied to a magneto-optical disk apparatus will be described in detail with reference to the drawings. The same parts as those described above are designated by the same reference numerals and detailed description thereof is omitted.

FIG. 1 shows a main part of a magneto-optical disk device 10 to which the present invention is applied. In this magneto-optical disk device 10, an optical pickup section 11 is arranged on the lower surface side of the rewritable magneto-optical disk 2. This figure shows only the configuration of the optical pickup unit 11 near the objective lens 5. The optical pickup section 11 is fixed on the support section 21 as shown in FIG. The support portion 21 is inserted through a slide shaft 22, and the optical pickup portion 11 is movable along the radial direction of the magneto-optical disc 2.

As shown in FIG. 1, the optical pickup unit 11
The laser light 4 emitted from a laser diode (not shown) in this example is condensed by an objective lens 5 having a diameter of, for example, about 5 mm and applied to a recording point p of the magneto-optical disk 2. In this example, the spot size s irradiated on the lower surface of the magneto-optical disk 2 is about 1
mm. The objective lens 5 is an actuator movable part 17
The actuator movable portion 17 is fixed to the tip of the actuator and is controlled by a focus coil (not shown) so as to be movable in the vertical direction. By moving the objective lens 5 up and down according to the surface wobbling of the magneto-optical disk 2, focus adjustment is performed so that the spot size s becomes a predetermined value, that is, 1 mm in this example. Since the structure of the actuator movable portion 17 is not directly related to the present application, detailed description thereof will be omitted.

An electromagnetic coil 18 is wound around and fixed to the outer periphery of the objective lens 5 above the movable portion 17 of the actuator. The lower portion of the electromagnetic coil 18 is wound with a diameter that matches the outer circumference of the objective lens 5, and the upper portion has a tapered shape that is wound with a smaller diameter. An opening 18b for allowing the laser beam 4 to pass therethrough is provided at the tip portion 18a where the winding diameter of the electromagnetic coil 18 is the smallest. Further, the tip portion 18a is designed to be as close as possible to the lower surface of the magneto-optical disk 2. When the electromagnetic coil 18 is energized, a magnetic field that concentrates on the optical axis is generated. For example, if a current that flows from the right side to the left side in the drawing is passed through the electromagnetic coil 18, a magnetic field that passes perpendicularly to the surface of the magneto-optical disk 2 from the lower surface to the upper surface is generated. Since the electromagnetic coil 18 is tapered so that the magnetic field is concentrated near the recording point p, the magnetic flux distribution is maximized particularly near the recording point p where the laser beam 4 is focused (near the optical axis).

In this way, by making the electromagnetic coil 18 as close as possible to the side of the magneto-optical disk 2 and forming the tip thereof in a tapered shape, the leakage of the magnetic flux generated by the electromagnetic coil 18 can be greatly reduced, and recording can be performed. The magnetic flux can be efficiently concentrated near the point p. Therefore, the magnetic flux density near the recording point p becomes high, and as a result, the magnetic flux required for recording or erasing can be obtained, and the small electromagnetic coil 18 can be used, so that the power consumption can be greatly reduced. Further, even if the magneto-optical disk 2 has a surface wobbling, the electromagnetic coil 18 moves up and down together with the actuator movable portion 17 and the objective lens 5 by the focus adjustment. Therefore, the gap g between the electromagnetic coil 18 and the magneto-optical disk 2 is always Holds constant. Therefore, the magnitude of the magnetic flux applied to the recording point p is always constant.

Further, since the electromagnetic coil 18 and the optical pickup section 11 are both arranged under the magneto-optical disk 2, it is not necessary to arrange parts on the upper side of the magneto-optical disk 2 as in the conventional case, so that the entire apparatus can be realized. It is possible to reduce the height of. When the magneto-optical disk 2 stored in the cartridge 25 (FIG. 10) is used, the cartridge 2
Since a mechanism for sliding the shutter 26a (FIG. 10) on the upper side of 5 is not required, the configuration of the entire apparatus can be simplified.

FIG. 3 shows a magneto-optical disk device 20 of the second embodiment to which the present invention is applied. This figure shows only the configuration of the optical pickup unit 31 near the objective lens 5. The objective lens 5 is attached to the tip of the actuator movable portion 17.
A magnetic path forming portion 37 formed of a ferrite core or the like is fixed to the outer periphery of the objective lens 5 in order to focus the magnetic flux at the recording point p of the magneto-optical disk 2. The lower portion of the magnetic path forming portion 37 has a diameter that is substantially the same as the outer diameter of the objective lens 5, and has a tapered shape that becomes smaller toward the tip. An opening 37b for allowing the laser beam 4 to pass therethrough is provided at the tip portion 37a where the diameter of the magnetic path forming portion 37 is the smallest. Further, the tip portion 37a is designed to be as close as possible to the lower surface of the magneto-optical disk 2.

As shown in FIGS. 3 and 4, a magnetic coil holding portion 38, which is formed by a ferrite core or the like and has a J-shaped cross section, is arranged around the magnetic path forming portion 37. It is attached to the fixed portion 40. While the actuator movable portion 17 moves up and down for focus adjustment, the actuator fixing portion 40 is a portion attached and fixed to the optical pickup portion 31 and does not move up and down. A groove 38a is provided on the upper side of the coil holding portion 38 along the circumferential direction, and an electromagnetic coil 39 is wound around the groove 38a.

The objective lens 5 and the magnetic path forming portion 37 move up and down together with the actuator moving portion 17 during focus adjustment. On the other hand, the coil holder 38 and the electromagnetic coil 39
Is fixed to the actuator fixing portion 40, so that it does not move up and down by focus adjustment. As described above, since the winding portion of the electromagnetic coil 39 is separated from the actuator movable portion 17, the weight of the actuator movable portion 17 does not increase, and the accuracy and responsiveness of focus adjustment are prevented from being degraded. It is possible. Further, the coil holding portion 38 prevents the loss of the magnetic field generated by the electromagnetic coil 39, and the tapered magnetic path forming portion 37 reduces the leakage loss of the magnetic flux generated by the electromagnetic coil 39 to a great extent. The magnetic flux can be efficiently concentrated in the vicinity of p. Thus, the recording point p
The magnetic flux density becomes high in the vicinity, and as a result, the magnetic flux required for recording or erasing can be obtained.

FIG. 5 shows a magneto-optical disk device 30 according to the third embodiment of the present invention. In this magneto-optical disk device 30, the tapered magnetic path forming portion 37 is formed as in the second embodiment.
Is attached to the tip of the actuator movable portion 17 of the optical pickup portion 41. Further, the coil holding portion 42 formed of a magnetic material such as ferrite is attached to a chassis 44 fixed to a device body (not shown) or the like. As shown in FIG. 6, the coil holding portion 42 has a horizontally long shape extending over the entire recording area in the radial direction of the magneto-optical disk 2. A linear groove portion 42a is provided in the center of the coil holding portion 42 along the radial direction of the magneto-optical disk 2 according to the moving range of the optical pickup portion 41, and the optical pickup portion 41 is movable there. It is arranged. In addition, the coil holding unit 42 includes an optical pickup unit 41.
A groove 42b that surrounds the moving range is formed as a recess, and the electromagnetic coil 43 is wound around the groove 42b.

In this magneto-optical disk device 30, the optical pickup section 41 moves along the groove 42a of the coil holding section 42 and follows the signal track of the magneto-optical disk 2. In this way, since the optical pickup unit 41 is independent of the coil holding unit 42 and the electromagnetic coil 43, it is possible to prevent the weight of the optical pickup unit 41 from increasing. As a result, the actuator movable portion 17 (FIG. 5)
The focus adjustment for the magneto-optical disk 2 and the tracking operation by the radial movement of the magneto-optical disk 2 are stabilized, and the recording / reproducing operation is improved.

[0027]

As described above, according to the present invention, the pickup means having the objective lens for converging the laser light modulated corresponding to the data to be recorded on the optical disk, and the auxiliary magnetic field are applied to the disk. In the disc recording / reproducing apparatus, which is provided with a static magnetic field generating means for
A static magnetic field generating means is provided around the objective lens.

Therefore, according to the present invention, the magnetic field can be efficiently applied to the recording point with a small electromagnetic coil.
It is possible to significantly reduce power consumption. If the electromagnetic coil is moved up and down together with the objective lens,
Since the gap between the electromagnetic coil and the magneto-optical disc is always kept constant by the focus adjustment, it is possible to always give a constant magnetic field to the optical disc and improve the stability of the recording and erasing operations. Further, since the electromagnetic coil and the optical pickup unit are both arranged under the optical disk, the height of the entire device can be lowered and the size can be reduced. When using the optical disk housed in the cartridge, there is no need for a mechanism for sliding the shutter on the upper side of the cartridge, which has the effect of simplifying the overall configuration of the apparatus.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a main part of a magneto-optical disk device 10 of a first embodiment to which a disk recording / reproducing device according to the present invention is applied.

2 is a perspective view showing a main part of the magneto-optical disk device 10. FIG.

FIG. 3 is a configuration diagram showing a main part of a magneto-optical disk device 20 of a second embodiment.

4 is a perspective view showing a main part of the magneto-optical disk device 20. FIG.

FIG. 5 is a configuration diagram showing a main part of a magneto-optical disk device 30 of a third embodiment.

6 is a perspective view showing a main part of the magneto-optical disk device 30. FIG.

FIG. 7 is a diagram showing recording, erasing and reproducing operations of a light modulation method.

FIG. 8 is a perspective view showing a first example of a conventional disc recording / reproducing apparatus.

FIG. 9 is a perspective view showing a second example of a conventional disc recording / reproducing apparatus.

FIG. 10 is a configuration diagram showing a main part of a conventional disc recording / reproducing apparatus.

[Explanation of symbols]

 1, 11, 31, 41 Optical pickup unit 2 Magneto-optical disk 3, 18, 39, 43 Electromagnetic coil 4 Laser light 5 Objective lens 10, 20, 30 Magneto-optical disk device 17 Actuator moving part 37 Magnetic path forming part 38, 42 Coil holding part 44 Chassis

Claims (5)

[Claims] 1. A pickup means having an objective lens for converging a laser beam modulated corresponding to data to be recorded on an optical disk, and a static magnetic field generating means for applying an auxiliary magnetic field to the disk. A disk recording / reproducing apparatus in which the optical pickup means is arranged so as to face the optical disk, wherein the static magnetic field generating means is provided around the objective lens. 2. The disk recording / reproducing apparatus according to claim 1, wherein the static magnetic field generating means is provided on the outer periphery of the objective lens and is configured to move integrally with the objective lens. 3. The static magnetic field generating means is a coil, and the coil has a tapered shape in which the diameter gradually decreases toward the disc surface of the optical disc within a range that does not interfere with the laser light. 2. The disc recording / reproducing apparatus according to item 2. 4. The static magnetic field generating means is fixed along the moving direction of the objective lens, and magnetic path forming means for forming a magnetic path for increasing magnetic flux density is provided on the outer periphery of the objective lens. The disk recording / reproducing apparatus according to claim 1, which is characterized in that. 5. The disc recording / reproducing apparatus according to claim 4, wherein the magnetic path forming means has a tapered shape in which the diameter gradually decreases toward the disc surface of the optical disc within a range in which the laser light is not interfered with. .