JP3402631B2 - Magneto-optical recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field modulation recording type light for applying a magnetic field whose polarity is inverted according to recording information to a magneto-optical recording film on a recording medium. The present invention relates to a magnetic recording / reproducing device. 2. Description of the Related Art In a magneto-optical recording / reproducing apparatus, for example, in a magneto-optical disk apparatus using a disk-shaped recording medium, a recording film composed of a perpendicular magnetization film such as a Tb-Fe thin film on a transparent disk-shaped substrate. Irradiating the magneto-optical recording film with a light spot focused by a condenser lens through an optical head and applying a bias magnetic field in a perpendicular direction to the magneto-optical recording film by a bias magnetic field generating coil at the same time As a result, the magnetization direction of the recording film is recorded as recording data on the light spot irradiated portion. In such a magneto-optical disk drive,
As a recording method capable of overwriting, for example, there is a magnetic field modulation method. In this magnetic field modulation method, when information is rewritten, the recording film is irradiated with a spot of a laser beam focused by a condenser lens, and at the same time, a modulation magnetic field according to recording data is applied by a magnetic head for magnetic field modulation. Data is recorded as the direction of magnetization of the recording film. FIG. 5 shows a configuration of a recording head section of an apparatus disclosed in Japanese Patent Application Laid-Open No. 4-106746 as an example of a magneto-optical disk apparatus of the magnetic field modulation system. [0005] An optical system driving actuator 5 for driving the moving optical system 3 in the radial direction of the disk is connected to the moving optical system 3 for irradiating the recording and reproducing light beams. A magnetic head 4 for applying a modulation magnetic field according to recording data is disposed at a position facing the moving optical system 3 with the disk interposed therebetween, and is connected to one end of a bracket 7 via a suspension 6. . This bracket 7
The moving optical system 3 is connected to the other end of the moving optical system 3, and the moving optical system 3 and the magnetic head 4 are integrally connected by a bracket 7. As described above, the moving optical system 3 and the magnetic head 4 are integrally connected to each other, and are moved in the radial direction of the disk. Is maintained. FIG. 6 shows the distribution of the recording magnetic field on the magneto-optical disk surface and the allowable range of the light spot position. Since the relative positional relationship between the moving optical system 3 and the magnetic head 4 is maintained, the position of the light spot irradiated by the moving optical system 3 is necessary for writing data in the magnetic field distribution generated by the magnetic head 4. It can be always positioned within the range of a suitable magnetic field, so that data can be written reliably. [0008] In an optical disk apparatus using a disk-shaped recording medium, the position of the light spot on the medium is coarsely positioned by, for example, a linear motor that moves the moving optical head, and at the same time, the object position is adjusted. Generally, fine movement positioning is performed by a tracking actuator that moves a lens or tilts an angle of a mirror. Here, the linear motor can move the light spot over the entire area of the disk in the radial direction, but the generated acceleration is small, and the tracking actuator has a small moving range but large generated acceleration. In a magneto-optical disk drive of the optical modulation recording system, a recording magnetic field is always generated over the entire area of the disk in the radial direction. Therefore, when performing a seek operation of moving the light spot from an arbitrary track to another track, the seek control is performed by a method utilizing the high-speed response of the tracking actuator without considering the recordable range of the magnetic field described above, It is possible to perform a quick seek operation. Therefore, the time required for recording and reproduction can be reduced. On the other hand, in the magneto-optical disk drive of the magnetic field modulation recording system, when the seek operation is completed and the track following operation is started, the light spot should be within the allowable range of the magnetic field distribution required for recording information. It is necessary to perform seek control. That is, if a seek operation is performed by a tracking actuator having a large generated acceleration, the light spot moves beyond the range of the magnetic field capable of recording information.
It is necessary to perform the seek operation at a low speed or switch to the track following operation after the light spot enters the range of the magnetic field in which information can be recorded after the seek operation. For this reason, the acceleration that can be generated by the tracking actuator cannot be fully utilized, and there is a disadvantage that the seek operation takes a longer time than the optical modulation recording apparatus. The present invention has been made in view of these circumstances, and in a magneto-optical recording / reproducing apparatus of a magnetic field modulation recording system, a seek operation for moving a light spot from an arbitrary track to another track is shortened. It is an object of the present invention to provide a device capable of performing such operations. A magneto-optical recording / reproducing apparatus according to the present invention applies a magnetic field whose polarity has been inverted by a magnetic field applying means to a recording film in accordance with recording information, and provides a high output from an optical head. The information is recorded by irradiating the laser light, the laser light of low output from the optical head is applied to the recording film, and the information is reproduced from the change in the polarization state of the reflected light. And the magnetic field applying means,
First driving means for integrally moving in a direction substantially perpendicular to a track provided on the recording film, and second driving means for moving a light spot formed by the laser beam with respect to the optical head And a seek control means for outputting a drive signal to the first and second drive means so that the light spot moves from an arbitrary track to another arbitrary track. So,
The seek control means includes a first seek control means and a second seek control means.
And a second seek control means.
The magnetic field control means controls the magnetic field distribution formed on the recording film by the magnetic field applying means so as to move the light spot at a high speed beyond a range where information can be recorded .
Seek control means includes a control to move the light spot so as not to exceed the information recordable range at a low speed as compared with the case of the seek control according to the second seek control means
And, further, it selects the first seek control means when in the case of performing the reproduction operation of the information after the seek operation is completed selects the second seek control means performs the recording operation of the information after the seek operation is completed And a seek operation selecting means. When the information reproducing operation is performed after the seek operation has been completed, the seek control means controls the magnetic field distribution formed on the recording film by the magnetic field applying means at a high speed beyond the information recordable range. A drive signal is output to move the spot. Further, when the recording operation of the information after the seek operation ends, the seek control unit, Before moving the light spot so as not to exceed the information recordable range at a relatively low speed. This Reniyo is, the seek time in the case of performing the reproduction operation of the information after seek, operation ends is reduced. Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 relate to an embodiment of the present invention.
FIG. 2 is a configuration explanatory view showing the configuration of the magneto-optical recording / reproducing apparatus, and FIG. 2 is a diagram in the direction orthogonal to the tracks on the magneto-optical disk.
FIG. 3 is an intensity distribution diagram showing the distribution of the intensity of the magnetic field generated by the magnetic field head. FIG. 3 shows the relative movement between the light spot and the magnetic field head when the seek operation is performed by the first and second seek control means. FIG. 9 is an operation explanatory diagram showing a change in a typical displacement amount. As shown in FIG. 1, the magneto-optical recording / reproducing apparatus of this embodiment is a magnetic head as a magnetic field applying means for applying a modulation magnetic field according to recording data to a magneto-optical disk 11 as a recording medium. 12 and an optical head 17 for irradiating a light beam are arranged to face each other. The optical head 17 is provided with an objective lens 13 for condensing a light spot on the magneto-optical disk 11, supported by a leaf spring 14. Further, a tracking actuator 15 as a second driving means for moving the objective lens 13 in a direction orthogonal to a track on the magneto-optical disk 11, and the objective lens 1 by the tracking actuator 15
3 is provided with an objective lens position detector 16 for detecting displacement. The optical head 17 includes a light source (not shown) and other optical elements. The optical head 17 and the magnetic field head 12 are
They are integrally and mechanically connected by a connecting member 18. The optical head 17 is connected to a linear motor 19 as first driving means for moving the optical head in a direction perpendicular to the track of the magneto-optical disk 11. The optical head 17 and the magnetic field head 12 are connected to each other. Magneto-optical disk 1
It is designed to move integrally in a direction perpendicular to one track. The optical head 17 is connected to a track following control means 20 and a track counting means 21 to which a tracking error signal indicating the amount of deviation between the light spot and the track on the magneto-optical disk is input. It has become. The track following control means 20 is further adapted to receive an objective lens position signal output from the objective lens position detector 16 and to form an optical spot based on the tracking error signal and the objective lens position signal. Each drive signal for the tracking actuator 15 and the linear motor 19 is output so as to follow the track. The track counting means 21 counts the number of light spots crossing the track on the basis of the tracking error signal, and counts the traversed track value as a first seek control means 22, a second seek control means 23, a control mode switching means 24.
Output. The first seek control means 22 and the second seek control means 23 respectively provide the output of the track counting means 21, the objective lens position signal output from the objective lens position detector 16, and the controller 27. The tracking actuator 15 and the linear motor 19 are moved so that the light spot moves to the target track based on the number of tracks (the number of moving tracks) from the track that is currently being followed by the light spot to the track to be moved. Are output as respective drive signals. FIG. 2 shows the distribution of the intensity of the magnetic field generated by the magnetic field head 12 in the direction perpendicular to the tracks on the magneto-optical disk 11. FIG. 2 is a schematic rewrite of FIG. The origin in FIG. 2 is the center position of the magnetic field head 12. The minimum value of the magnetic field strength required for recording a signal is Hmin (this minimum value Hmin
Is determined by the sensitivity of the medium, the laser power to be recorded, and the like).
To + d. The first seek control means 22 sends a drive signal to the tracking actuator 15 such that the light spot at the end of the seek does not deviate from the magnetic field head 12 to a region where the magnetic field intensity is smaller than Hmin. The output is provided to the linear motor 19. On the other hand, the second seek control means 23 sends to the tracking actuator 15 and the linear motor 19 a drive signal such that the light spot at the end of the seek is largely deviated from the magnetic field head 12 to a region where the magnetic field intensity becomes smaller than Hmin. Output. Therefore, when the seek control is performed by the second seek control means 23, the first seek control means 22
The light spot can be moved to the target track in a shorter required time than in the case of the seek control using The control mode switching means 24 performs seek control of the control mode based on the seek start signal output from the controller 27, the number of tracks to be traversed (the number of moving tracks), and the output of the track counting means 21. Alternatively, a mode switching signal for switching to track following control is output. The outputs of the first seek control means 22 and the second seek control means 23 are inputted to a seek signal selecting means 25 as a seek operation selecting means. The seek signal selecting means 25 receives a read / write signal (R / W signal) from the controller 27 to instruct whether to perform an information reading operation or a writing operation after the seek operation, and the seek operation is started. The seek signal selecting means 25
Indicates that in the case of a reading operation, the second seek control
Select the output of stage 23 and, for a write operation,
The output of the first seek control means 22 is selected and output. The output of the seek signal selecting means 25 and the output of the track following control means 20 are input to an input signal switching means 26. The input signal switching means 26 converts the respective drive signals for the tracking actuator 15 and the linear motor 19 into the output of the seek signal selection means 25 and the track following control according to the mode switching signal output from the control mode switching means 24. The output is switched to one of the outputs of the means 20. Next, the operation of this embodiment will be described.
The light emitted from the light source in the optical head 17 is
3 irradiates the recording medium surface of the magneto-optical disk 11 as a light spot. Then, the light reflected by the magneto-optical disk 11 returns to the optical head 17 and enters a light receiving element (not shown). The light receiving element outputs a tracking error signal indicating a displacement between the light spot and the information track on the magneto-optical disk to the track following control means 20 and the track counting means 21. In the track following control mode, the track following control means 20 controls the tracking actuator 15 based on the tracking error signal and the objective lens position signal output from the objective lens position detector 16.
And a drive signal for the linear motor 19 is generated. The input signal switching means 26 outputs the output of the track following control means 20 to the tracking actuator 15 and the linear motor 19. Thus, the tracking actuator 15 and the linear motor 19 are set so that the deviation between the light spot and the track on the magneto-optical disk falls within an allowable range, and the deviation of the light spot from the center of the magnetic field head is described above. The drive is performed so as to fall within a range of ± d which is a range of the magnetic field strength necessary for information recording. Writing and reading of information are performed in the state of the track following control mode. When the control mode switching unit 24 receives a seek start signal and a signal indicating the number of tracks to be moved from the controller 27 in the track following mode, the control mode switching unit 24 switches the mode to the input signal switching unit 26. A signal is output, and the drive signal of the tracking actuator 15 and the linear motor 19 is switched to a seek control signal by the input signal switching means 26 to enter a seek control mode. In the seek control mode, an operation of moving the light spot on the magneto-optical disk from the track currently followed by the light spot to another arbitrary track is performed. At this time, the track counting means 21 counts zero crossings of the tracking error signal, detects and outputs the number of tracks traversed by the light spot. The first seek control means 22 and the second seek control means 23 include an objective lens position signal output from the objective lens position detector 16 and
The number of traversing tracks output from the track counting means 21 and the number of tracks to be traversed to move to the target track output from the controller 27 are input so that the light spot moves toward the target track. A signal (seek control signal) for driving the tracking actuator 15 and the linear motor 19 is output. Here, when performing an information writing operation on the destination track, the seek signal selecting means 25
Selects and outputs the output of the first seek control means 22 according to the instruction of the R / W signal output from the controller 27. When performing an information reading operation on the destination track, the seek signal selecting means 25 selects the output of the second seek control means 23 according to an instruction of the R / W signal output from the controller 27. Output. When the seek operation is performed by the output of the first seek control means 22 or the second seek control means 23, the moving speed of each light spot and the relative displacement between the light spot and the magnetic field head 12 FIG. 3 shows an example of the change. 3A shows the case of a seek operation based on the output of the first seek control unit 22, and FIG. 3B shows the case of the seek operation based on the output of the second seek control unit 23. The second seek control means 2 shown in FIG.
In the case of the seek operation by No. 3, the target track is reached in a shorter time, and the seek operation is completed.
Is out of the range -d to + d of the information recordable magnetic field. Therefore, when performing the information reading operation after the end of the seek operation that does not require the recording operation, the seek operation is performed by the second seek control unit 23 to reduce the seek time. On the other hand, in the case of the seek operation by the first seek control means 22 shown in FIG. 3A, the seek operation takes a long time, but the light spot is within the range of the information recordable magnetic field at the start of track following. It is in. Therefore, when performing the information writing operation after the end of the seek operation, the seek operation is performed by the first seek control unit 22 so that the recording operation can be started immediately after the end of the seek operation. In the seek control mode, if the number of tracks to be moved specified by the controller 27 matches the number of traversing tracks output by the track counting means 21, the control mode switching means 24 controls the input signal switching means 26. To the track following control means 20 by the input signal switching means 26.
The mode is switched to the track following mode so that the drive signal is output to the tracking actuator 15 and the linear motor 19. As described above, in this embodiment, only when information is recorded after the seek operation, the seek of the light spot with respect to the magnetic field head is performed so as not to be out of the recordable range of the magnetic field generated by the magnetic head. When the information is not recorded, the seek time is reduced by performing high-speed seek control such that the light spot deviates from the above range after the seek operation. As a result, the seek time in the data reading operation can be reduced, and the time required for recording and reproduction can be reduced. In this case, the seek time in the data recording operation is the same as that of the related art. However, when a magneto-optical disk device is used as an external storage device of the computer, the read operation has a high ratio, so that the substantial time required for the seek operation can be reduced. This has the effect. FIG. 4 shows a reference example developed up to the present invention.
FIG. 2 is a configuration explanatory view showing the configuration of FIG. This reference example is different from the above-described embodiment of the present invention.
However, only the second seek control means 23 is provided,
This is an example in which the information recording operation is performed after confirming that the displacement of the light spot falls within the information recordable range after the seek operation. As shown in FIG. 4, the tracking actuator 15 is moved so that the light spot moves to the target track.
Only the second seek control means 23 is provided as means for outputting respective drive signals to the motor and the linear motor 19, and the seek signal selection means 25 is omitted. The objective lens position signal output from the objective lens position detector 16 as the position detecting means is also input to the comparator 28 as the comparing means. Based on the objective lens position signal, the position of the objective lens 13 is compared with a recordable range ± d determined by the magnetic field distribution by the magnetic field head 12, and if the position of the objective lens 13 is within the recordable range, a write enable signal is output. The data is output to the magnetic field modulation recording means 29 as the recording control means. The magnetic field modulation recording means 29 confirms that it is in a writable state by the write permission signal, and then controls laser power control for setting the emission power of a semiconductor laser (not shown) to a recording level, and a magnetic head. A magnetic field head current control for modulating a current flowing through the twelve coils according to data to be recorded is performed. Other components are the same as those of the above-described embodiment of the present invention, and the same components are denoted by the same reference numerals and description thereof will be omitted. The operation in the track following mode of the present embodiment is the same as that of the above-described embodiment of the present invention, and the description of the operation is omitted. In the seek control mode, the seek operation is performed by the output of the second seek control means 23. That is,
Regardless of whether the write operation or the read operation is performed after the seek operation, the amount of deviation between the light spot and the magnetic field head 12 during the seek operation or immediately after the seek operation can exceed the recordable range ± d of the magnetic field distribution. A seek control signal having a characteristic is output from the second seek control means 23, and the tracking actuator 15 and the linear motor 1
9 is driven at high speed. After reaching the target track by the seek operation, the write enable signal from the comparator 28 is not output to the magnetic field modulation recording means 29 unless the light spot is within the recordable range of the magnetic field distribution. No write operation is performed. Thereafter, in the track following mode, the linear motor 19 is driven in the direction in which the amount of displacement of the objective lens is reduced, and when the light spot enters the recordable range of the magnetic field distribution, the comparator 28 outputs a write enable signal, Data writing is performed. Note that the read operation becomes possible from the time when the seek operation is completed regardless of the write enable signal. As described above , also in this reference example ,
As in the embodiment of the present invention, the seek time in the data reading operation can be reduced. Further, in the present embodiment , the same seek control means is used regardless of whether data is read or written after seek, so that the present invention using two seek control means is used . Real
Configuration compared to 施例 there is an effect that it becomes easy. As described above, according to the present invention, in the magneto-optical recording / reproducing apparatus of the magnetic field modulation recording system, the time of the seek operation for moving the light spot from an arbitrary track to another track is reduced. There is an effect that can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 3 relate to one embodiment of the present invention, and FIG. 1 is a structural explanatory view showing a structure of a magneto-optical recording / reproducing apparatus. FIG. 3 is an intensity distribution diagram showing a distribution of a magnetic field intensity generated by a magnetic field head in a direction orthogonal to a track. FIG. 3 shows a moving speed of a light spot and a light when a seek operation is performed by first and second seek control means. FIG. 4 is an operation explanatory view showing a change in a relative displacement amount between a spot and a magnetic field head. FIG. 4 is an explanatory view showing a configuration of a magneto-optical recording / reproducing apparatus according to a reference example developed up to the present invention. 5 is an explanatory diagram showing a configuration example of a recording head section in a magneto-optical disk device of a magnetic field modulation system. Explanation] 11 ... Magneto-optical Disk 12 Magnetic field head 13 Objective lens 15 Tracking actuator 16 Objective lens position detector 17 Optical head 19 Linear motor 20 Track following control means 21 Track count means 22 First seek control means 23 2 seek control means 24 control mode switching means 25 seek signal selection means 26 input signal switching means 27 controller 28 comparator

Claims (1)

(57) [Claim 1] By applying to a recording film a magnetic field whose polarity has been inverted according to recording information by a magnetic field applying means, and irradiating a high-power laser beam from an optical head. Performs information recording, irradiates the recording film with low-output laser light from an optical head, reproduces information from a change in the polarization state of the reflected light, and the optical head and the magnetic field applying means. First driving means for integrally moving in a direction substantially perpendicular to a track provided on the recording film; and second driving means for moving a light spot formed by the laser light with respect to the optical head. And a seek control means for outputting a drive signal to the first and second drive means so that the light spot moves from an arbitrary track to another arbitrary track. I, the seek control unit, a first seek control means and the
And a second seek control means.
The magnetic field control means controls the magnetic field distribution formed on the recording film by the magnetic field applying means so as to move the light spot at a high speed beyond a range where information can be recorded .
Seek control means includes a control to move the light spot so as not to exceed the information recordable range at a low speed as compared with the case of the seek control according to the second seek control means
And, further, it selects the first seek control means when in the case of performing the reproduction operation of the information after the seek operation is completed selects the second seek control means performs the recording operation of the information after the seek operation is completed A magneto-optical recording / reproducing apparatus, comprising: