JP2002197742A - Temperature controlling method for magneto-optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature controlling method by which the temperature of a magneto-optical disk can get to a Curie point with high precision. SOLUTION: A magnetic field modulation head is provided with a temperature sensor 27 at a sliding part 23 brought in contact with a disk surface or a temperature detecting coil 29 for detecting the temperature of the magneto- optical disk 1 on a core wound by a magnetic field generating coil 26. In the temperature controlling method, the temperature at the time before the sliding part is brought into contact with the disk and at the time when a prescribed time passes after the sliding part is brought into contact with the disk are detected by a temperature sensor 27. Temporal temperature change of a recording layer is predicted based on the detected temperatures, and laser beam power of a heating means is controlled so that no deviation from a prescribed recording temperature may be realized at least in the initial stage when the recording begins.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus for recording / reproducing information by using a magneto-optical effect, and more particularly, to stabilizing a recording layer of a magneto-optical disk (hereinafter simply referred to as a disk). The present invention relates to a method for controlling a temperature to reach a Curie point.

[0002]

2. Description of the Related Art A magneto-optical disk such as a mini disk (MD) has a magnetic thin film formed on a substrate, and information is recorded by changing the magnetization direction of the magnetic thin film. One of the recording methods is a method of recording by modulating a bias magnetic field. In this method, a laser beam is emitted in a DC manner and irradiated on a recording medium, and its temperature is raised to near the Curie point. By applying the applied magnetic field, a magnetization pattern corresponding to information is formed.

The information recorded in this manner is reproduced (read) by irradiating a recording medium with a laser beam emitted in a DC manner with a lower output than at the time of recording by using the magneto-optical effect from the returned light. be able to. By the way, in the information recording method, since the recording medium is heated by irradiating the laser beam, if the output of the laser beam deviates from the optimum value, the recording state may not be good. As a countermeasure, it has been proposed to arrange a temperature sensor inside or near the magnetic field modulation head and to optimally control the power of the laser beam based on the output of this sensor.

FIGS. 11 (a), 11 (b), and 11 (c) show Japanese Unexamined Patent Publication No.
FIG. 1 shows a magnetic field modulation head of this type disclosed in Japanese Patent Publication No. 48-48. In FIG. 1A, the temperature sensor 14 is provided on the side of the magnetic field generating portion facing the magneto-optical disk 1, that is, on the lower surface of the yoke 12 supporting the pair of electromagnets 11 through the heat insulating material 13. In the configuration shown in (b), a temperature sensor 14 is mounted via a heat insulating material 13 in a gap between the yokes 12 supporting the electromagnets 11, and further, as shown in (c). In this device, a coil 16 is wound around a core 15 to form a magnetic head for overwriting, and a lead wire of a temperature sensor 14 is adhered to a side surface thereof.

[0005]

The magnetic field modulation head described above controls the power of the laser beam based on the output of the temperature sensor attached to the head to stably reach the temperature of the magneto-optical disk to the Curie point. It is intended to be. However, in these magnetic field modulation heads, a temperature sensor is disposed at a position separated from the disk surface by a space, and furthermore, the disk itself must be housed in a cartridge or the temperature must be detected during rotation. For this reason, the ambient temperature was detected rather than the disk temperature.

In a car or portable optical information recording / reproducing apparatus, when recording (hereinafter, also referred to as "writing") immediately after inserting a disc, the disc itself may be cold while the disc itself is warm. In this case, if the power of the laser beam is controlled based on the detection value of the temperature sensor of the magnetic field modulation head, the temperature of the disk may not reach the Curie point, and writing may not be performed properly. Further, in a magneto-optical recording / reproducing apparatus for data, when data is written under the same conditions, even if data can be written, the write level is low and the error rate may be increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and accurately detects the temperature of a disk. Even when the temperature of the apparatus or the apparatus and the temperature of the disk inserted therein are different, It is an object of the present invention to provide a temperature control method that allows the temperature of the disk to reach the Curie point with high accuracy.

[0008]

The present invention comprises the following 1) and 2) for solving the above-mentioned problems. That is, 1) a removable magneto-optical disk is mounted, and a magnetic field modulating head for applying a modulating magnetic field to a recording medium of the magneto-optical disk in a state where the magneto-optical disk is rotated; In recording information by integrally driving a heating means for causing the temperature of the recording medium to reach the vicinity of the Curie point, a magneto-optical disk for controlling the laser beam power of the heating means based on the temperature information of the recording medium. In the temperature control method, the magnetic field modulation head includes a sliding portion that is brought into contact with a disk surface of the magneto-optical disk, and a temperature detection unit that performs temperature detection near the sliding surface. At a point in time before the contact with the magneto-optical disk and at a point in time when a predetermined time has elapsed since the sliding portion was brought into contact with the magneto-optical disk. Each temperature is detected, the temperature change of the recording medium corresponding to the elapsed time is predicted based on the obtained detected temperature, and at least at the initial stage of starting the recording, the deviation from the predetermined recording temperature is brought close to zero. A method for controlling the temperature of a magneto-optical disk, comprising controlling a laser beam power of a heating means. 2) A magnetic field modulation head for applying a modulation magnetic field to a recording medium of the magneto-optical disk while the removable magneto-optical disk is mounted and the magneto-optical disk is rotated, and the recording medium is irradiated with a laser beam. When recording information by integrally driving a heating means for causing the temperature of the recording medium to reach the vicinity of the Curie point, temperature control of a magneto-optical disk for controlling a laser beam power of the heating means based on temperature information of the recording medium. In the method, the magnetic field modulation head includes a magnetic field generating coil for applying a magnetic field to the magneto-optical disk, and the magnetic field generating coil is also used for temperature detection, or the magnetic field generating coil is wound. A magnetic field generator in which a coil for temperature detection is wound around a core to be mounted;
Using a magnetic field generating part and a sliding part formed integrally with the disk surface of the magneto-optical disk, using the sliding part in contact with the magneto-optical disk, Detecting a temperature of the magneto-optical disk by passing a test current to the coil or the temperature detecting coil, and controlling a laser beam power of the heating means based on the obtained detected temperature; Temperature control method.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. FIG. 1 is a sectional view showing the configuration of a first embodiment of a magnetic field modulation head applied to the present invention. In FIG. 1, a head arm 21 has a base end thereof,
That is, the left end of the drawing (not shown) is connected to the head driving unit of the optical information recording / reproducing apparatus. A suspension 22 is provided between an intermediate portion and a tip portion of the head arm 21.
Are supported so as to be able to move up and down at the tip. On the lower surface of the tip of the suspension 21, a sliding part 23 and a magnetic field generating part are provided.
One integrated with 24 frames 24A is joined. The sliding portion 23 has two bottom surfaces so that it slightly projects from the magnetic field generating portion 24 toward the disk 1 (downward in the drawing). For this reason, the sliding portion 23 is
When the magnetic field generating unit 24 is brought into contact with the disk surface of the disk 1, the magnetic field generating unit 24 faces the disk 1 with a constant gap.
Thereby, the intensity of the modulation magnetic field applied to the disk surface can be made constant. Also, the magnetic field generator 24 includes
An "E" -shaped core 25 is mounted, and a coil 26 is wound around the center leg thereof via a bobbin (not shown). Further, the inside of the sliding portion 23 is preferably 0.1 mm from the contact surface.
A temperature sensor 27 made of a thermistor or a diode is mounted at a position of 5 mm. On the upper surface of the suspension 22,
A wiring 28 composed of an FPC (Flexible Print Circuit) is placed, and a lead wire at the tip of the wiring 28 is connected to the coil 26 and the temperature sensor 27, so that excitation current can be supplied and temperature can be detected.

In the magnetic field modulation head having such a configuration, since the temperature sensor 27 is mounted near the contact surface with the disk 1, the sliding portion 23 of the temperature sensor 27 is brought into contact with the magneto-optical disk, and In the state where the rotation of the magnetic disk is stopped, it is possible to detect a temperature which is almost the same as that of the disk 1.
If the temperature sensor 27 is brought too close to the contact surface, the temperature sensor 27 may be broken due to wear of the sliding portion 23. Therefore, a position 0.5 mm from the contact surface is preferable as shown in the figure. .

FIG. 2 is a sectional view showing the structure of a second embodiment of the magnetic field modulation head applied to the present invention. In the figure, FIG.
The same elements as those described above are denoted by the same reference numerals and description thereof will be omitted. In the second embodiment, a temperature detection coil 29 is wound around a central leg of a core 25 as a temperature sensor. That is, a resin-made bobbin (not shown) having two winding portions in the axial direction is used in the center leg of the core 25, and a magnetic field generating coil 26 is provided near the disk 1 and a temperature Each of the detection coils 29 is mounted. In this case, the number of turns of the magnetic field generating coil 26 is 33 and the resistance value is 5 ohms, and the number of turns of the temperature detecting coil 29 is 33 and the resistance value is 50 ohms (25 ° C.).

The magnetic field modulation head shown in FIG.
Since the temperature sensor 27 is located near the contact surface with the magnetic disk, the sliding portion 23 is brought into contact with the magneto-optical disk, and when the magneto-optical disk 1 is stopped, it is possible to detect a temperature that is almost equal to that of the disk 1. However, when the disk 1 rotates, the detection accuracy is reduced due to the influence of frictional heat.
In this regard, the magnetic field modulation head shown in FIG. 2 has slightly lower detection accuracy when the magneto-optical disk 1 is stopped,
There is an advantage that it is hardly affected by frictional heat due to the rotation of. Further, since it is only necessary to wind another coil 29 for temperature detection around the same core as the magnetic field generating coil 26, it can be manufactured more easily and at a lower cost than mounting a thermistor or a diode. There are advantages too.

FIG. 3 is a block diagram showing the overall configuration of an optical information recording / reproducing apparatus for implementing the method for controlling the temperature of a magneto-optical disk according to the present invention. In FIG. 3, the magneto-optical disk 1 has a plurality of spiral tracks on which information is recorded or written at CLV (constant linear velocity). The spindle motor 2 drives the magneto-optical disk 1 to rotate. The pickup device 3 mainly has a function of converging a laser beam to make its focus coincide with the disk surface of the magneto-optical disk 1, detecting the reflected light with a sensor, reproducing the obtained signal, and tracking the reproduced signal to a track. And a function to superimpose a high-frequency signal upon reading. FIG. 1 or FIG.
When writing information, a loading means for bringing the sliding portion into contact with the disk surface with a predetermined pressure is attached, and the position is controlled so as to follow the track integrally with the pickup device 3. It is supposed to be.

On the other hand, the spindle motor control circuit 31 controls the rotation speed of the spindle motor 2 so as to maintain CLV based on an output signal of a signal processing circuit 38 described later. This is to drive the modulation head 4 integrally and to control the positioning with respect to the track. The voltage detection circuit 33 amplifies and outputs a voltage generated in a temperature sensor or a temperature detection coil mounted on the magnetic field modulation head 4, as will be described in detail later.

The preamplifier 34 is a pickup device 3
A signal corresponding to the laser return light detected by the sensor inside is input and amplified, and then applied to the signal processing circuit 38, while controlling the laser output in the pickup device 3 according to the output command of the controller 35. I do. The controller 35 performs the following control using a series of digital signal processing systems such as a signal processing circuit 38, a memory controller 39 for the memory 40, and a conversion circuit 41 in response to a command from the key 36. At the time of reproduction, when an RF signal is input to the signal processing circuit 38 via the preamplifier 34, the signal is converted into an audio signal and output. At the time of reproduction and writing, the speed of the spindle motor 2 is detected and a speed signal that becomes CLV is applied to the spindle motor control circuit 31. At the time of reproduction and writing, a tracking error and a focus error necessary for accurate tracing of the laser beam are detected, and a signal for correcting these errors is applied to the pickup drive circuit 32. During writing, the audio signal is quantized and the writing circuit
37, the control signal of the power of the laser beam is applied to the magnetic field modulation head 4 via the preamplifier 34.
Add to the pickup device 3. When writing the start, and the time before the contacting the sliding portion of the magnetic field modulation head 4 to the magneto-optical disc 1, respectively voltage from contacting the sliding portion on the magneto-optical disk with the elapse of the predetermined time The temperature is detected based on the output signal of the detection circuit 33, and the temperature change of the recording layer corresponding to the elapsed time is predicted based on the obtained detected temperature. A signal that controls the power of the laser beam to approach zero
It is added to the pickup device 3 via 34.

Next, a method for controlling the temperature of a magneto-optical disk according to the present invention will be described. When the magnetic field modulation head 4 shown in FIG. 1 is used and a thermistor is used as the temperature sensor, the circuit shown in FIG. 4 is provided for temperature measurement. That is, the test signal TE of the controller 35
A switch SW1 whose contact is closed by ST and a resistor R
1, a diode D and a resistor R2 are connected in series between a high potential power supply Vcc and a ground point as a low potential power supply.
On the other hand, one end of the resistor R3 is connected to the anode of the diode D, the other end is connected to the inverting input terminal (-) of the operational amplifier OP, and one end of the resistor R4 is connected to the cathode of the diode D. The end is operational amplifier O
It is connected to the non-inverting input terminal (+) of P. A feedback resistor R5 is connected between the inverting input terminal and the output terminal of the operational amplifier OP, and a resistor R6 is connected between the non-inverting input terminal of the operational amplifier OP and the ground.

Here, when the test signal TEST is applied, the switch SW1 is closed, and a voltage corresponding to the temperature at that time is generated across the thermistor TH. This voltage is amplified by an amplifier circuit including an operational amplifier OP, converted into digital data by an A / D converter 35A of the controller 35, and used for controlling the power of the laser beam. When a diode is used as the temperature sensor, a circuit configuration is used in which a diode D is connected instead of the thermistor TH as shown in FIG. The other configuration of FIG. 5 is the same as that of FIG.

FIG. 6 is an explanatory diagram of the operation when the controller 35 controls the power of the laser beam based on the output of the operational amplifier OP shown in FIG. When the power is turned on to the optical information recording / reproducing apparatus placed in an environment where the ambient temperature is 0 ° C., the internal temperature of the apparatus rises to 25 ° C. as shown by a curve A. Therefore, it is assumed that a magneto-optical disk having its own temperature of 0 ° C. is inserted at time t1, which is 10 minutes or more, for example, 16 minutes after the power is turned on. The temperature of the magneto-optical disk rapidly rises from 0 ° C. to 25 ° C. as shown by a curve B. Writing to the magneto-optical disk is performed by loading a magnetic field modulation head onto the disk. In this embodiment, the ambient temperature at 25 ° C. is detected based on the output of the operational amplifier OP before loading. Next, the magnetic field modulation head is loaded onto the magneto-optical disk, and when a predetermined time, for example, 200 msec has elapsed, the temperature of the magneto-optical disk is detected based on the output of the operational amplifier OP. The temperature detection so far is performed while the rotation of the spindle motor 2 is stopped. From these two detected values, it is possible to predict a change in temperature of the magneto-optical disk corresponding to a change in time. That is, the temperature change determined by the heat capacity of the entire apparatus and the heat capacity of the disk is stored in the ROM in advance, and the temperature change corresponding to the subsequent time can be determined from the temperature detection value when the magnetic field modulation head is loaded on the magneto-optical disk. Therefore, when writing is started at time t2, the temperatures of the magneto-optical disk after time t2 can all be predicted. Therefore, the power of the laser beam is controlled so as to approach a temperature value set in advance for the predicted value.

By the way, in the circuit configuration shown in FIG. 4, it is assumed that the thermistor TH as a temperature sensor has a resistance value of 1.1 kΩ at 0 ° C. and 1 kΩ at 25 ° C. When the resistance value is 1 kΩ, the switch SW1
Is closed, and the resistance values of the resistors R1 and R2 are determined so that a voltage of exactly 1 V is generated when the high potential power supply Vcc is connected thereto. Therefore, at 0 ° C., a voltage of 1.1 V is applied to the operational amplifier OP, and at 25 ° C., a voltage of 1.0 V is applied to the operational amplifier OP. Here, if the resistance values of the resistors R3 and R5 are determined so that the amplification factor becomes 1,
These voltages are directly applied to the A / D converter 35A. If an A / D converter 35A having a power supply voltage of 3V and an 8-bit output is used, digital data becomes "256" at a voltage of 3V, so that digital data of "85" is obtained for a voltage of 1V. Is obtained, and digital data “94” is obtained for a voltage of 1.1V. When the magnetic field modulation head is not loaded on the magneto-optical disk, A
If the digital data "85" is output from the / D converter and the digital data "94" is output from the A / D converter when the magnetic field modulation head is loaded on the magneto-optical disk, this difference is It will represent the ambient temperature difference. Further, by comparing these digital data with the above-described table written in the ROM, it is possible to predict the temperature of the magneto-optical disk thereafter. The processing procedure at the time of writing including these processing can be shown as the processing of steps 101 to 116 in FIG.

FIG. 8 shows a configuration example of a voltage detection circuit 33 and a write circuit 37 corresponding to the magnetic field modulation head shown in FIG.
And a temperature detecting coil 29 are connected in series. on the other hand,
A P-channel MOSF is connected between the high potential power supply Vcc and the ground point.
A series connection circuit of ETQ1 and N-channel MOSFET Q3 (hereinafter, P-channel MOSFET is simply referred to as PMOSFET and N-channel MOSFET is simply referred to as NMOSFET), and PMOSFET Q2 and NMOSFET
Q4 is connected to the series connection circuit. PMOSFE
One end of a coil 26 for generating a magnetic field is connected to a connection point between TQ1 and NMOSFET Q3, that is, a connection point between drains, and another connection point between PMOSFET Q2 and NMOSFET Q4, that is, a connection point between drains, The end and one end of the temperature detecting coil 29 are connected. The other end of the temperature detecting coil 29 is NM
The drain of the OSFET Q5 is connected, and this NMOS
The source of ETQ5 is connected to ground. The switch SW1 sets the write data W. DATA and the ground voltage are switched by a test signal TEST and input. The output terminal of the switch SW1 is connected to a PMOSFET Q1 and an NMOSFET via an inverter IN.
It is connected to each gate of Q3, and via a buffer BU to the normally-closed input terminal of the changeover switch SW2 and the gate of the NMOSFET Q4. The normally open input terminal of the changeover switch SW2 is connected to the ground point, and the output terminal is connected to the gate of the PMOSFET Q2. Another changeover switch SW
3 has a normally closed input terminal grounded, a normally open input terminal connected to a high potential power supply Vcc, and an output terminal connected to an NMOSFET.
Connected to the gate of Q5. The voltage generated between both ends of the temperature detecting coil 29 is equal to the voltage of the operational amplifier O described above.
The signal is amplified by an amplifier including P and resistors R3, R4, and R5, and applied to the A / D converter 35A.

In the circuit shown in FIG.
If P and the resistors R3, R4, R5 are the components of the voltage detection circuit 33 of FIG. 3, those excluding these components and the magnetic field generator 24 are the components of the write circuit 37 of FIG. ing. These circuits also apply a test voltage to the temperature detection coil 29 during temperature detection before starting writing,
During writing, a current that switches between a positive direction and a negative direction is passed through the coil 26 for generating a magnetic field. Here, at the time of temperature detection, the changeover switches SW2, SW3, and SW4 are all switched to the opposite side to the illustrated direction by the test signal TEST. Thereby, the PMOSFET Q2
, NMOSFETs Q3 and Q5 are turned on, and PMOSF
The ETQ1 and the NMOSFET Q4 are turned off, and current flows to both the magnetic field generating coil 26 and the temperature detecting coil 29. At this time, the voltage generated at both ends of the temperature detecting coil 29 is amplified by an amplifier circuit centered on the operational amplifier OP.

When a write command is applied, a test voltage is applied to the temperature detecting coil 29 while the spindle motor 2 is stopped to detect the ambient temperature. Subsequently, the magnetic field modulation head 4 is loaded onto the magneto-optical disk 1 with the spindle motor 2 stopped, and the sliding portion is brought into contact with the disk surface. Until the resistance value changes due to the difference between the ambient temperature and the temperature of the magneto-optical disk 1, for example, 20
Wait until 0 msec elapses. It is not necessary to wait until the temperature of the magnetic field modulation head completely matches the temperature of the magneto-optical disk. Thereafter, a test voltage is again applied to the temperature detecting coil 29 to detect the temperature of the magnetic field modulation head at that time. The current temperature of the magneto-optical disk 1 is detected from the difference between these temperatures, and the power of the laser beam is controlled accordingly.

As the temperature detecting coil 29, a coil having a temperature of 45 Ω at 0 ° C. and 50 Ω at 25 ° C. is used. Then, a voltage of 1.8 V is generated at both ends of the temperature detecting coil 29 at 0 ° C. by flowing a current of 40 mA. When this voltage is amplified by a factor of two with the operational amplifier OP, 0.9 V is obtained. And the power supply voltage is 3
Digital data "75" is obtained by inputting the V signal to the 8-bit A / D converter 35A. On the other hand, during writing, all the changeover switches SW1, SW2, and SW3 are held in the state shown in the figure. Then, the write data W. When an "H" level signal is applied as DATA, the PMOSFET Q1 and the NMOSFET Q4 are turned on, the PMOSFET Q2 and the NMOSFET Q3 are turned off, and a current in the positive direction (from right to left in the drawing) is applied to the magnetic field generating coil 26. And write data W. When an "L" level signal is applied as DATA, the PMOSFET Q1 and the NMOSFET Q4 are turned off, the PMOSFET Q2 and the NMOSFET Q3 are turned on, and a negative current (left to right in the drawing) is supplied to the magnetic field generating coil 26. Shed.

In this embodiment, the coil 26 for generating the magnetic field and the coil 29 for detecting the temperature are connected to form a so-called center tap type. May add a dedicated measurement circuit. By the way, each of the above embodiments is directed to a magnetic field modulation head provided with a temperature sensor or a coil for temperature detection in addition to the coil 26 for generating a magnetic field, but on the assumption that the sliding portion is brought into contact with the disk surface. Then, the temperature of the disk can be detected using the coil 26 for generating the magnetic field itself as a temperature sensor.

FIG. 9 shows a configuration example in which the coil 26 for generating a magnetic field is also used as a temperature sensor. Here, the drain of the NMOSFET Q3 is connected to the drain of the PMOSFET Q1 whose source is connected to the high potential power supply Vcc,
The source of the NMOSFET Q3 is connected to the input terminal of the switch SW5. An NMOS is connected to the drain of the PMOSFET Q2 whose source is connected to the high potential power supply Vcc.
The drain of the FET Q4 is connected and this NMOSFET
The source of Q4 is connected to the input terminal of switch SW5. The normally closed output terminal of the switch SW5 is grounded, and the normally open output terminal is connected to a low potential power supply Vss via a constant current source J. PMOSFET Q1 and NMOSFET Q
3 and the PMOSFET Q2 and NMOSFET
A series connection circuit of a resistor R1, a coil 26 for generating a magnetic field, and a resistor R2 is connected to a connection point of Q4.
The switch SW3 applies the write data W.V. to the normally closed input terminal.
DATA is added, the normally open input terminal is grounded, and the output terminal of the changeover switch SW3 is connected to the gates of the PMOSFET Q1 and NMOSFET Q3 via the inverter IN, and via the buffer BU.
It is connected to the gates of PMOSFET Q2 and NMOSFET Q4. The voltage generated at both ends of the coil 26 for generating a magnetic field is supplied to the operational amplifier OP and the resistor R3.
, R4, R5, and R6, and amplifies the amplified signal to an A / D converter.

Here, when detecting the temperature, all the changeover switches SW3 and SW5 are switched to the opposite side to the illustrated direction by the test signal TEST. As a result, the PMOSFET Q2 and the NMOSFET Q3 are turned on, and the PMOSFETs Q1 and NMOSFET Q4 are turned off, so that a current flows through the magnetic field generating coil 26 and the current is controlled to be constant by the constant current source J. At this time, the voltage generated at both ends of the magnetic field generating coil 26 is amplified by an amplifier circuit centered on the operational amplifier OP. Therefore, when a write command is applied, the spindle motor 2
While the operation is stopped, the magnetic field modulation head is in an unloading state, and a test current is supplied to the temperature detecting coil 29 to detect the ambient temperature. In this case, the magnetic field generating coil 26
Is 5.0Ω at 25 ° C. and 4.5 at 0 ° C.
The one that becomes Ω is used. Therefore, a voltage of 1.0 V is generated by applying a current of 200 mA to the temperature detection coil 29 of 5.0 Ω at 25 ° C. When this voltage is amplified by a factor of one with an operational amplifier OP, 1.0 V is obtained. Also, when the power supply voltage is 3 V and the data is input to an 8-bit A / D converter, digital data “85” is obtained. Here, the test current is cut off and the ROM
Alternatively, the temperature at that time, that is, the ambient temperature is obtained by using a table indicating the relationship between the digital data written in the EEPROM and the temperature.

Subsequently, the magnetic field modulation head 4 is loaded on the magneto-optical disk 1 with the spindle motor 2 stopped, and the sliding portion is brought into contact with the disk surface. Then, it waits until the resistance value changes due to the difference between the ambient temperature and the temperature of the magneto-optical disk 1, for example, 200 msec. It is not necessary to wait until the temperature of the magnetic field modulation head completely matches the temperature of the magneto-optical disk. Thereafter, a test voltage is applied to the temperature detecting coil 29 again to detect the temperature of the magnetic modulation head at that time. At this time, if the temperature is 0 ° C., 0.9 V is generated at both ends of the coil 26 for generating a magnetic field. When this voltage is amplified by a factor of one with an operational amplifier OP, the voltage is reduced to 0.1.
9V is obtained. By inputting this voltage to the A / D converter, digital data "76" is obtained. Also, here, the test current is cut off, and the ROM or EEPROM is previously determined based on the difference “9” from the digital data “85”.
The temperature at that time is obtained using a table indicating the relationship between the digital data written in the OM and the temperature.

As described above, the difference between the temperature before loading the magnetic field modulation head 4 on the magneto-optical disk 1 and the temperature at the time when a certain time has elapsed after loading is the temperature difference between the ambient temperature and the disk. As the temperature of the disk approaches the ambient temperature as time passes, a table of temperature asymptote preset in ROM based on the heat capacity of the entire apparatus and the heat capacity of the disk, and a magnetic field applied to the magneto-optical disk 1 The recording disk temperature at the time when the write instruction is issued is predicted based on the value of the timer that measures the time since the loading of the modulation head 4. Then, the laser beam output is controlled in accordance with the relationship between the predicted temperature and the voltage written in the ROM. Of course, since the magnetic field modulation head 4 is loaded onto the magneto-optical disk 1 immediately before writing, the temperature may be measured at this point.

Thereafter, the spindle motor 2 is started to detect a focus error and a tracking error of the laser beam with respect to the track, and the pickup device 3 is controlled so that these errors are close to zero.
By rotating the pickup at V, the pickup section is moved to the TOC (Table Of Contents) or UT near the innermost circumference of the disk.
It moves to OC (User Table Of Contents), reads necessary information, and writes there. It should be noted that the timer for measuring the time from the loading of the magnetic field modulation head 4 on the magneto-optical disk 1 is cleared when it is determined that the temperature of the magneto-optical disk 1 substantially matches the ambient temperature.

During writing, the changeover switches SW3, SW
5 are held in the state shown in the figure. Write data W. When an "H" level signal is applied as DATA, the PMOSFET Q1 and the NMOSFET Q4 are turned on, the PMOSFET Q2 and the NMOSFET Q3 are turned off, and a current in the positive direction (from right to left in the drawing) is applied to the magnetic field generating coil 26. And write data W. When an "L" level signal is applied as DATA, the PMOSFET Q1 and the NMOSFET Q4 are turned off, the PMOSFET Q2 and the NMOSFET Q3 are turned on, and a negative current (left to right in the drawing) is supplied to the coil 26 for generating a magnetic field. Shed.

FIG. 10 shows another configuration example in which the coil 26 for generating a magnetic field is also used as a temperature sensor. Here, a PMOS FE whose source is connected to the high potential power supply Vcc is used.
The drain of NMOSFET Q3 is connected to the drain of TQ1, and the source of NMOSFET Q3 is grounded. Also, the PM whose source is connected to the high potential power supply Vcc
The drain of the NMOSFET Q4 is connected to the drain of the OSFET Q2, and the source of the NMOSFET Q4 is grounded. PMOSFET Q1 and NMOSFET
The connection point of Q3, PMOSFET Q2 and NMOSFE
A series connection circuit of a resistor R1, a coil 26 for generating a magnetic field, and a resistor R2 is connected to the connection point of TQ4. The switch SW3 applies the write data W.V. to the normally closed input terminal. DATA is applied, the normally open input terminal is grounded, and the output terminal of the changeover switch SW3 is connected to the PMOSFET Q1 and the NMOSFET via the inverter IN.
It is connected to the gates of Q3 and to the gates of PMOSFET Q2 and NMOSFET Q4 via a buffer BU. The voltage generated at both ends of the magnetic field generating coil 26 is amplified by the above-described operational amplifier OP and an amplifier including resistors R3, R4, R5 and R6, and A
/ D converter.

Here, when detecting the temperature, the changeover switch SW3 is switched to the opposite side to the illustrated direction by the test signal TEST. Thereby, the PMOSFE
TQ2 and NMOSFET Q3 are turned on, and PMOSF
The ETQ1 and the NMOSFET Q4 are turned off, and a test voltage is applied to the magnetic field generating coil 26. At this time, the voltage generated at both ends of the magnetic field generating coil 26 is amplified by an amplifier circuit centered on the operational amplifier OP.

When a write command is applied, the magnetic field modulation head 4 is loaded onto the magneto-optical disk 1 while the spindle motor 2 is stopped, and the sliding portion is brought into contact with the disk surface. Then, for example, 200 ms until the resistance value changes due to the difference between the ambient temperature and the temperature of the magneto-optical disk 1.
Wait until ec has elapsed. It is not necessary to wait until the temperature of the magnetic field modulation head completely matches the temperature of the magneto-optical disk. Thereafter, a test voltage is applied to the temperature detecting coil 29 again to detect the temperature of the magnetic modulation head at that time. At that time, if it is 4.5Ω at 0 ° C., 400
When a current of mA flows, a voltage of 1.8 V is generated across the coil 26 for generating a magnetic field. When this voltage is amplified by a factor of two with the operational amplifier OP, 0.9 V is obtained. By inputting this voltage to the A / D converter, digital data "76" is obtained. At this time, the test current is cut off, and the temperature at that time is obtained by using a table indicating the relationship between the digital data previously written in the ROM or the EEPROM and the absolute value of the temperature. Next, the power of the laser beam is set according to the temperature, and predetermined writing is performed.

When the circuit configuration shown in FIG. 10 is adopted,
A changeover switch SW3 is added, and the test signal T
It is only necessary to switch by EST, but since a large current (400 mA) actually supplied at the time of writing flows, it is necessary to perform measurement in a short time so that the coil does not generate heat. In the above-described embodiment, the one using the temperature detecting coil 29 or the magnetic field generating coil 26 detects the temperature of the magneto-optical disk by using the change in the resistance value. If it changes, the magnetic permeability of the ferrite constituting the core also changes and the inductance changes, so that the temperature of the magneto-optical disk can be detected by using the change in impedance including the resistance value and the inductance.

[0035]

As is apparent from the above description, according to the method for controlling the temperature of a magneto-optical disk of the present invention, the time before the sliding portion comes into contact with the magneto-optical disk and the time when the sliding portion is moved The temperature is detected at each time when a predetermined time has elapsed after the contact with the magnetic disk, and the temperature change of the recording layer corresponding to the elapsed time is predicted based on the detected value. Since the power of the laser beam of the heating means is controlled so that the deviation from the recording temperature approaches zero, an effect is obtained that the temperature of the disk can accurately reach the Curie point. According to another method for controlling the temperature of a magneto-optical disk according to the present invention, in controlling the power of a laser beam, a coil for generating a magnetic field or a coil for detecting a temperature which only needs to be additionally wound on the coil is used. Since the temperature of the magneto-optical disk is detected by a unique method of passing a test current, the effect that the temperature of the disk can accurately reach the Curie point can be obtained, and a dedicated element for detecting the temperature ,
For example, there is no need to mount a thermistor, a diode, or the like, which has the effect that the configuration of the magnetic field modulation head can be simplified and the device cost can be reduced.

[Brief description of the drawings]

1 is a cross-sectional view showing a configuration of a first reference example of a magnetic field modulation head of the magneto-optical disc applied to the present invention.

FIG. 2 is a sectional view showing a configuration of a second reference example of a magnetic field modulation head of a magneto-optical disk applied to the present invention.

FIG. 3 is a block diagram showing an example of the configuration of an information recording / reproducing apparatus for implementing the method of controlling the temperature of a magneto-optical disk according to the present invention.

FIG. 4 is a circuit diagram showing a detailed configuration of main elements of the information recording / reproducing apparatus shown in FIG.

5 is a circuit diagram showing a detailed configuration of main components of the information recording / reproducing device shown in FIG.

FIG. 6 is a diagram showing a relationship between time and temperature for explaining a temperature control method for a magneto-optical disk according to the present invention.

FIG. 7 is a flowchart showing a processing procedure of the information recording / reproducing apparatus shown in FIG. 3 for explaining the method of controlling the temperature of the magneto-optical disk according to the present invention.

FIG. 8 is a circuit diagram showing another configuration example of an apparatus for performing the method of controlling the temperature of a magneto-optical disk according to the present invention.

FIG. 9 is a circuit diagram showing another example of the configuration of the apparatus for performing the method of controlling the temperature of a magneto-optical disk according to the present invention.

FIG. 10 is a circuit diagram showing still another example of the configuration of the apparatus for performing the method of controlling the temperature of a magneto-optical disk according to the present invention.

FIG. 11 is a sectional view and a side view showing a configuration example of a conventional magnetic field modulation head of a magneto-optical disk.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magneto-optical disk 3 Pickup device 4 Magnetic field modulation head 23 Sliding part 24 Magnetic field generating part 24A Frame of magnetic field generating part 25 Core 26 Magnetic field generating coil 27 Temperature sensor 29 Temperature detecting coil 31 Spindle motor control circuit 32 Pickup drive circuit 33 Voltage detection circuit 35 Controller 37 Write circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D075 CC04 CD11 CF03 CF10 5D091 AA08 CC18 FF20 HH11

Claims (2)

[Claims] A magnetic field modulation head for mounting a removable magneto-optical disk and applying a modulation magnetic field to a recording medium of the magneto-optical disk while rotating the magneto-optical disk;
When recording information by integrally driving a heating means for irradiating a laser beam to reach a temperature near the Curie point of the recording medium, the laser beam power of the heating means is determined based on the temperature information of the recording medium. In the method for controlling the temperature of a magneto-optical disk, the magnetic field modulation head includes a sliding portion that is brought into contact with a disk surface of the magneto-optical disk and a temperature detecting unit that detects a temperature near the sliding surface. Using, the temperature is detected at a point in time before the sliding part is brought into contact with the magneto-optical disk and at a point in time when a predetermined time has passed since the sliding part is brought into contact with the magneto-optical disk, A temperature change of the recording medium corresponding to an elapsed time is predicted based on the obtained detected temperature, and a deviation from a predetermined recording temperature at least in an initial period when recording is started. Controlling the laser beam power of said heating means so as to approach zero, the temperature control method of the magneto-optical disk, characterized in that. 2. A magnetic field modulation head for mounting a removable magneto-optical disk and applying a modulation magnetic field to a recording medium of the magneto-optical disk in a state where the magneto-optical disk is rotated;
When recording information by integrally driving a heating means for irradiating a laser beam to reach a temperature near the Curie point of the recording medium, the laser beam power of the heating means is determined based on the temperature information of the recording medium. In the method of controlling the temperature of a magneto-optical disk, the magnetic field modulation head includes a magnetic field generating coil for applying a magnetic field to the magneto-optical disk, and the magnetic field generating coil is also used for temperature detection, Alternatively, a magnetic field generating portion in which a temperature detecting coil is wound around a core around which the magnetic field generating coil is wound, and a disk surface of the magneto-optical disk are brought into contact with each other and formed integrally with the magnetic field generating portion. A slider having a sliding portion, and bringing the sliding portion into contact with the magneto-optical disk, and applying a test current to the magnetic field generating coil or the temperature detecting coil. Flow by detecting the temperature of the magneto-optical disk, and controls the laser beam power of said heating means based on the obtained detected temperature, the temperature control method of the magneto-optical disk, characterized in that.