JPH1125536A - Recording and playback device - Google Patents

Abstract

(57) [Problem] To provide a recording / reproducing apparatus capable of controlling a recording condition and a reproducing condition on a super-resolution optical recording medium. At the time of test writing, a test pattern generated by a test signal generation circuit is recorded on a magneto-optical disk, and is reproduced by a magnetic head without applying an external magnetic field. To determine the optimum recording conditions. At the time of test reading, information recorded on the magneto-optical disk 1 is reproduced both in the case where the external magnetic field is applied by the magnetic head 5 and in the case where the external magnetic field is not applied. Find conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light utilizing magnetic super-resolution in which an external magnetic field is applied to an optical recording medium to form an aperture (opening) smaller than the spot area of a light beam on the medium. Optimal recording /
The present invention relates to a recording / reproducing apparatus for performing a test write or a test read for obtaining a reproduction condition.

[0002]

2. Description of the Related Art In recent years, in order to improve the recording density, a reproducing layer is provided on a recording layer, and an opening (hereinafter, referred to as an aperture) smaller than a spot area of a light beam is generated in the reproducing layer, so that recording is performed. An optical recording medium for reading out layer marks at a high density has been developed. For example, JP-A-3-9305
The magneto-optical recording medium disclosed in Japanese Patent Application Publication No. 6-26,1992 has a recording layer for recording a recording mark, a reproducing layer on which the recording mark is transferred by exchange coupling with the recording layer, and an exchange coupling between the recording layer and the reproducing layer. It has a multilayer structure with a cutting layer that cuts force,
During reproduction, a high-density recording mark is reproduced by applying a reproducing magnetic field and generating magnetic super-resolution using a high-temperature portion generated behind the light spot as a mask.

In this method, since an aperture is formed in front of the light spot, generally, the FAD (Front Aperture Detec) is used.
tion). In addition, CAD (Center Aperture Detectio
n), RAD (Rear Aperture) with an aperture in the center
Detection) is known.

In these disks, recording marks are read out by a portion smaller than the spot area, that is, an aperture, by masking a part of the light spot by a high-temperature portion in the reproducing layer. At this time, the size of the high-temperature portion fluctuates due to a change in environmental temperature and variations in the characteristics of the disk, and accordingly, the area of the aperture also fluctuates. Therefore, it is necessary to control the size of the aperture and perform stable reproduction.

For example, as a method of controlling the aperture in the CAD system, a test read method disclosed in Japanese Patent Application Laid-Open No. H8-63817 reproduces a short mark and a long mark so that the amplitude ratio of a reproduced signal is constant. The size of the aperture is controlled by controlling the amount of reproduced light so as to be as follows. In this method, the size of the high-temperature portion is controlled by controlling the amount of reproduced light.
It is considered that it can be used also in the D system.

[0006] The above-mentioned changes in the environmental temperature and variations in the characteristics of the disk are not limited to the time of reproduction, but also the size of the recording marks at the time of recording. As a method of recording a fixed recording mark on a conventional optical recording medium in which magnetic super-resolution does not occur, there is a test writing method disclosed in Japanese Patent Application Laid-Open No. 7-249226. In this method, a test pattern is recorded while changing the recording light amount in advance, and the recording light amount is controlled so that a test signal obtained by reproducing the test pattern has an optimum signal level.

[0007]

However, in the above-described conventional configuration, when the above-described test read is performed on an optical recording medium that causes magnetic super-resolution, an optimal recording mark can be obtained if the recording mark is accurately recorded in advance. Although the reproduction light amount can be controlled, if a recording mark of an incorrect size is recorded due to the above-mentioned change in the environmental temperature or the like, there is a problem that the reproduction light amount is controlled to be erroneous.

For this reason, a method of controlling the recording light amount in advance for an optical recording medium in which magnetic super-resolution is generated by a conventional test write can be considered. However, when the recording state is detected by reproducing the test pattern, the size of the aperture fluctuates due to the above-mentioned change in the environmental temperature and the like, so that there is a problem that an erroneous recording state is detected.

That is, even if a conventional test write is performed on an optical recording medium that causes the above-described super-resolution, it is not possible to optimally control the amount of recording light, thereby making it impossible to record a recording mark of an accurate size. In addition, there is a problem that the reproduction light amount cannot be optimally controlled even when the test read is performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to perform test writing and test reading without being affected by fluctuations in environmental temperature, etc. An object of the present invention is to provide a recording / reproducing apparatus capable of determining a reproducing condition.

[0011]

According to a first aspect of the present invention, there is provided a recording / reproducing apparatus wherein a recording layer for recording a recording mark and information magnetically recorded on the recording layer are transferred by an exchange coupling force via a cutting layer. A magneto-optical recording medium having a multi-layer structure of a reproducing layer, which has a multilayer structure, and a cutting layer that cuts the exchange coupling force between the recording layer and the reproducing layer in a region where the temperature is equal to or higher than a predetermined temperature when irradiated with a light beam. The recording / reproducing of data is performed by irradiating the reproducing layer with a light beam while applying an external magnetic field to the magneto-optical recording medium. In order to solve the above-described problem, information is recorded on the optical recording medium. Means for reproducing information from an optical recording medium, a magnetic field applying means for applying an external magnetic field to the optical recording medium, and detecting a signal level of a reproduced signal obtained by reproduction by the reproducing means. Reproduction signal detecting means Controlling the recording means to record information on the optical recording medium, controlling the reproduction means to reproduce the information, and detecting the signal level of the reproduction signal by the reproduction signal detection means, Control means for controlling the magnetic field applying means so that the external magnetic field is selectively applied at the time of reproducing the information.

According to the above arrangement, the control means controls the recording means to record information on the optical recording medium, and reproduces the information by the reproducing means. When it is desired to detect the signal level of the reproduced signal during the reproduction of information, the control means can selectively apply an external magnetic field by controlling the magnetic field applying means. Then, the reproduction signal detecting means detects the level of the reproduction signal obtained by the reproduction.

Accordingly, when reading information,
That is, during normal reproduction, by applying an external magnetic field, an aperture can be generated in the reproduction layer of the optical recording medium to perform high-resolution reproduction, and at the same time, information can be reproduced without applying an external magnetic field. Then, by detecting the level of the reproduced signal by the reproduced signal detecting means, it is possible to perform the reproduction without causing an aperture. In this case, the optical signal is not affected by the fluctuation of the environmental temperature and the variation of the disk. The recording state of the recording mark on the recording medium can be detected.

Further, for example, the level of a reproduction signal when reproducing information while applying an external magnetic field and the level of a reproduction signal when reproducing information without applying an external magnetic field are detected. By comparing these, a change in resolution from the reproduced signal can be accurately detected.

According to a second aspect of the present invention, there is provided a recording / reproducing apparatus, in addition to the configuration of the first aspect, wherein a test signal generating means for generating a test signal and a recording condition setting means for setting a recording condition are provided. The control means controls the recording condition setting means to set recording conditions in the recording means, controls the recording means, and generates a test signal generated by the test signal generation means on the optical recording medium. When a test pattern is recorded, the reproducing means is controlled to reproduce the test pattern without applying an external magnetic field, and when the level of the reproduced signal obtained by the reproduction is detected by the reproduced signal detecting means, It is characterized in that recording conditions are controlled based on the level of the reproduction signal, and optimum recording conditions are obtained.

According to the above configuration, the recording conditions include, for example, the light amount of the light beam applied to the optical recording medium during recording,
The magnetic field intensity applied to the optical recording medium. The control means controls the recording condition setting means so that the recording means
For example, a specific recording condition within a certain appropriate range is set. Then, the recording means is controlled to record a test pattern on the optical recording medium, and the reproducing means reproduces the test pattern. During the reproduction, no external magnetic field is applied by the magnetic field applying means. Then, the reproduction signal detecting means detects the level of the reproduction signal obtained by the reproduction and transmits the level to the control means. As described above, the control unit can acquire the level of the reproduction signal corresponding to the plurality of recording conditions within the above range. Then, the control means compares the acquired levels of the reproduction conditions,
The recording condition for recording the optimal reproduction signal is determined as the optimal recording condition.

Thus, it is possible to accurately determine the optimum recording conditions in a recording / reproducing apparatus for performing reproduction by generating an aperture in a reproducing layer of an optical recording medium without being affected by fluctuations in environmental temperature and variations in disks. Becomes Therefore,
If recording is performed on the optical recording medium using these recording conditions,
Recording can be performed under optimal conditions. For this reason,
It is possible to record information with few errors.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the test pattern forms a recording mark larger than a spot diameter of a light beam applied to the optical recording medium by the reproducing means. It is a feature that it is a pattern that does.

With the above configuration, it is possible to compensate for a decrease in resolution when no external magnetic field is applied due to a large recording mark, and to detect a recording state with a high S / N ratio.

According to a fourth aspect of the present invention, there is provided a recording / reproducing apparatus including, in addition to the configuration of the first aspect, a reproducing condition setting means for setting a reproducing condition. By controlling the setting means, the reproducing condition is set in the reproducing means, and the reproducing means is controlled to reproduce the information recorded on the optical recording medium in both the state where the external magnetic field is applied and the state where the external magnetic field is not applied. When the level of the reproduction signal obtained by the reproduction is detected by the reproduction signal detecting means, the reproduction condition is controlled based on the level of the reproduction signal, and the optimum reproduction condition is obtained. I have.

According to the above arrangement, the reproduction conditions include, for example, the light amount of the light beam applied to the optical recording medium during reproduction,
This is the strength of the magnetic field applied to the optical recording medium. The control means controls the reproduction condition setting means to cause the reproduction means to set a specific reproduction condition, for example, within a certain appropriate range. Then, by controlling the reproducing means, in both the state where the external magnetic field is applied and the state where the external magnetic field is not applied,
The information recorded on the optical recording medium is reproduced. When the level of the reproduced signal obtained by the reproduction is detected by the reproduced signal detecting means, the control means analyzes the level and determines whether or not the obtained reproduced signal is the optimum reproduced signal. I do. If the reproduction signal is not optimal, the reproduction condition is changed and the level of the reproduction signal is acquired again and analyzed. If it is determined that the signal is the optimum reproduction signal, the reproduction condition in this reproduction is determined as the optimum reproduction condition.

Thus, when an external magnetic field is applied to the optical recording medium, that is, when reproduction is performed by generating an aperture smaller than the spot diameter of the light beam in the reproducing layer, when the external magnetic field is not applied, that is, when the external magnetic field is not applied, Since the level of the reproduced signal is detected in both the case where the reproduction is performed without generating the aperture and the case where the reproduction is performed, the change in the resolution can be known by comparing these levels, and the result of the comparison is determined to be a predetermined value. The reproduction condition can be optimized so that the value of

According to a fifth aspect of the present invention, in addition to the configuration of the fourth aspect, the reproducing means reproduces a recording mark smaller than a spot diameter of a light beam applied to the optical recording medium by the reproducing means. The control means controls reproduction conditions based on the level of the reproduction signal.

According to the above configuration, the resolution between the case where the external magnetic field is applied and the case where the external magnetic field is not applied can be largely changed by a small recording mark, and the reproducing light amount or reproducing magnetic field intensity at the time of reproducing the information can be increased by the high S / N ratio. Can be controlled.

[0025]

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

FIG. 1 is a block diagram showing the configuration of a recording / reproducing apparatus according to the present embodiment (hereinafter referred to as the present apparatus). As shown in FIG.
, A feed motor 3, a laser driver 4, a magnetic head 5, a magnetic head driver 6, a reproduction signal detection circuit 7 as reproduction signal detection means, and control means, reproduction condition setting means and recording condition setting means. It comprises a control circuit 8 and a test signal generation circuit 9 as test signal generation means, and performs recording and reproduction on the magneto-optical disk 1 as an optical recording medium. The recording means includes the optical pickup 2, a laser driver 4, a magnetic head 5, and a magnetic head driver 6, and the reproducing means includes the optical pickup 2 and the laser driver 4. Further, the magnetic head 5 also functions as a magnetic field applying unit.

The optical pickup 2 irradiates the magneto-optical disk 1 with a light beam b, and
This is for reading information recorded in the. Further, the optical pickup 2 converts the read information into a reproduction signal h.
To the reproduction signal detection circuit 7.

The feed motor 3 is for moving the optical pickup 2 in accordance with an instruction from the control circuit 8 so that a predetermined portion of the magneto-optical disk 1 is irradiated with the light beam b. The laser driver 4 controls the power of the light beam emitted by the optical pickup 2 by transmitting an optical pickup drive signal e to the optical pickup 2 according to an instruction from the control circuit 8.

The magnetic head 5 is for applying a magnetic field to the magneto-optical disk 1 for recording information. The magnetic head driver 6 controls the strength of the magnetic field applied by the magnetic head 5 by transmitting a magnetic head drive signal d to the magnetic head 5 according to an instruction from the control circuit 8.

The reproduction signal detection circuit 7 detects the level of the reproduction signal read by the optical pickup 2 and transmits it to the control circuit 8 as signal level data i. Here, the level of the reproduction signal refers to the magnitude of the amplitude of the reproduction signal.

The control circuit 8 controls the feed motor 3 by transmitting a movement control signal a to the feed motor 3. In addition, the control circuit 8 controls the laser driver 4 by transmitting the light amount control signal g to the laser driver 4. Further, the control circuit 8 controls the magnetic head driver 6 by transmitting a magnetic field control signal f to the magnetic head driver 6.

The test signal generating circuit 9 is for transmitting a test signal for controlling a recording condition described later to the laser driver 4 and the magnetic head driver 6 as a test signal c.

The magneto-optical disk 1 used in this apparatus is
For example, as shown in FIG. 2, a test write area 11 for writing a test pattern at the time of test write is formed on the outer peripheral portion, and an information recording area 12 for writing normal recording information is formed inside the test write area 11. .

FIG. 4 is a block diagram showing a configuration for processing the magnetic field control signal f and the light quantity control signal g from the control circuit 8 in the magnetic head driver 6 and the laser driver 4. As shown in FIG. 4, the magnetic head driver 6 includes a magnetic head drive circuit 21 and a D / A converter 22, and the laser driver 4 includes an optical pickup drive circuit 23 and a D / A converter 24. ing. The optical pickup 2 has a semiconductor laser 25 for emitting a light beam b.

The magnetic field control signal f sent from the control circuit 8 is, for example, 8-bit binary data,
The converter 22 receives the magnetic field control signal f, converts it into an analog signal, and sends it to the magnetic head drive circuit 21.
The magnetic head drive circuit 21 sends a magnetic head drive signal d based on the analog signal to the magnetic head 5 to control a magnetic field generated by the magnetic head 5. In this way, the magnetic head driver 6 receives the instruction from the control circuit 8
The external magnetic field generated by the magnetic head 5 can be accurately controlled. As a result, the intensity of the external magnetic field can be accurately reduced or turned off to a level at which no aperture is generated, based on an instruction from the control circuit 8.

The light quantity control signal g sent from the control circuit 8 is, for example, 8-bit binary data similarly to the magnetic field control signal f, and the D / A converter 24 receives the light quantity control signal g. , And sends it to the optical pickup drive circuit 23. The optical pickup drive circuit 23 sends an optical pickup drive signal e based on the analog signal to the semiconductor laser 25 provided in the optical pickup 2 and controls the light amount of the light beam b generated by the semiconductor laser 25. In this way, the laser driver 4 can accurately control the light amount of the light beam b generated by the optical pickup 2 based on the instruction of the control circuit 8.

FIG. 5 is a block diagram showing the configuration of the reproduction signal detection circuit 7. As shown in FIG. 5, the reproduction signal detection circuit 7 includes an amplifier 31, a low-pass filter 32, an amplitude detection circuit 33, and an A / D converter.

The reproduction signal h sent from the optical pickup 2 is an analog signal, and the amplifier 31 receives the reproduction signal h, amplifies it, and sends it to the low-pass filter 32. The low-pass filter 32 improves the S / N ratio of the amplified reproduced signal h and sends the signal to the amplitude detection circuit 33. The amplitude detection circuit 33 detects the signal level of the reproduced signal h whose amplification and S / N ratio have been improved, and sends it to the A / D converter 34. The A / D converter 34 converts this signal level into, for example, 8-bit binary data, and transmits it to the control circuit 8 as signal level data i. In this way, the reproduction signal detection circuit 7 can transmit an accurate reproduction signal level to the control circuit 8.

The case of reading recorded information on the magneto-optical disk 1 by the present apparatus having the above configuration will be described below with reference to FIG. However, at the time of reading, the read characteristics are different between when the external magnetic field is turned on and when the external magnetic field is turned off.

First, the case where the external magnetic field is turned on is shown in FIG. The magneto-optical disk 1 has a multilayer structure having a reproducing layer 41, a cutting layer 42, and a recording layer 43, and a pattern magnetically recorded on the recording layer 43 is transferred to the reproducing layer 41 by exchange coupling.

At the time of reading information recorded on the magneto-optical disk 1, the reproducing layer 41 of the magneto-optical disk 1 is irradiated with a light spot p. A high-temperature portion q (hatched portion in FIG. 6) is generated in front of the light spot p, that is, in the direction of movement of the recording medium (x direction in FIG. 6). High temperature section q
In the region (2), the temperature of the cutting layer 42 rises to the Curie temperature or higher, and the magnetic field of the cutting layer 42 disappears. Therefore, the exchange coupling between the recording layer 43 and the reproduction layer 41 is broken. The above description exemplifies the case of the FAD system.

At this time, when an external magnetic field Hex is applied to the magneto-optical disk 1 by the magnetic head 5, the magnetization of the reproducing layer 41 in the high temperature section q is aligned in the direction of the external magnetic field Hex. Therefore, the recording mark recorded on the recording layer 43 is masked in the high temperature section q. Accordingly, in this case, the low-temperature portion excluding the high-temperature portion q from the light spot p becomes the aperture r, and the aperture r becomes the readout region (the horizontal line portion in FIG. 6A). When the external magnetic field is turned on, the aperture r becomes smaller than the light spot p, so that information recorded on the magneto-optical disk 1 at a high density can be reproduced. In the present embodiment, only the external magnetic field Hex corresponds to the external magnetic field described in the claims.

On the other hand, when the external magnetic field is turned off, as shown in FIG.
Since the external magnetic field Hex is not applied even when the magnetic field of the recording layer 43 disappears, the leakage magnetic field Hl
By k, the same pattern as that of the recording layer 43 is transferred. Therefore, unlike the case where the external magnetic field is turned on, a mask by the high temperature portion q does not occur, and the entire irradiation region of the light spot p becomes a readout region (the horizontal line portion in FIG. 6B) as it is, and the environmental temperature The recording mark can be reproduced regardless of the change of the recording mark.

In FIG. 6B, in addition to turning off the external magnetic field Hex, if the intensity is reduced to be smaller than the leakage magnetic field Hlk, the effect of the mask is lost and the external magnetic field Hex is substantially turned off. It goes without saying that the recording mark is transferred.

Thus, the magneto-optical disk 1 of the present apparatus
Will be described in detail. FIG. 7 is a flowchart showing the recording / reproducing operation. In this device,
The recording operation on the magneto-optical disk 1 and the reproducing operation of the information recorded on the magneto-optical disk 1 can be performed separately. In the following description, it is assumed that the reproducing operation is performed after the recording operation. I do.

First, before the apparatus performs a recording operation on the magneto-optical disk 1, a test write is performed to appropriately adjust the light amount of the light beam b applied to the magneto-optical disk 1. Therefore, the optical pickup 2 is moved to the test write area 11 of the magneto-optical disk 1 (S1), and the test write is performed while changing the recording conditions such as the recording light amount and the recording magnetic field strength (S2). When the test write is completed and the light amount of the light beam b is adjusted, the optical pickup 2 is moved to the information recording area 12 of the magneto-optical disk 1 (S
3) Information recording is performed using the optimized recording conditions (S4).

A reproducing operation is performed subsequent to the recording operation. Even before the reproducing operation, in order to adjust the light amount of the light beam b, the reproducing conditions such as the reproducing light amount and the reproducing magnetic field intensity are changed. The information recorded in the information recording area is reproduced and a test read is performed (S5). When the test read ends, information is reproduced based on the optimized reproduction conditions (S6).

The operation of the test write in FIG. 7 will be described in detail below. The test write includes a step of recording a test pattern in a test write area 11 of the magneto-optical disk 1, a step of reproducing the test pattern and detecting a recording state, and determining an optimum recording light amount and a magnetic field intensity based on the detected recording state. Process.

First, in the test pattern recording step, as shown in FIG. 1, a movement control signal a is output from the control circuit 8 to the feed motor 3, and the optical pickup 2 is used to test the magneto-optical disk 1 shown in FIG. Moved to area 11.
A test signal c is issued from the test signal generation circuit 9,
The optical pickup drive signal e sent to the laser driver 4
Is sent to the semiconductor laser in the optical pickup 2. Further, a magnetic field control signal f is sent from the control circuit 8 to the magnetic head driver 6. The magnetic head driver 6 converts the magnetic field control signal f into a magnetic head drive signal d and sends it to the magnetic head 5. Then, the magnetic head 5 applies an external magnetic field to the magneto-optical disk 1 based on the magnetic head drive signal d. Further, the control circuit 8 sends a light quantity control signal g to the laser driver 4, and records the test signal c while changing the recording light quantity of the light beam b.

Next, in the step of reproducing the test signal c, first, the external magnetic field is turned off by the magnetic field control signal f. As a result, the occurrence of super-resolution during reproduction is temporarily stopped, and the recorded test pattern can be reproduced without being affected by fluctuations in the environmental temperature. Next, the optical pickup 2
The test pattern is read out, and the test pattern signal h is sent to the reproduction signal detection circuit 7. The reproduction signal detection circuit 7 detects the signal level data i of the test pattern signal h, sends it to the control circuit 8, and stores it in a memory (not shown).

When the reproduction of the test pattern is completed, the external magnetic field is turned on again by the magnetic field control signal f, the recording light amount is slightly increased, and the operation returns to the recording of the test signal c. While slightly increasing the recording light amount in this way, the test signal c is recorded in a predetermined light amount range, and the recording state at that time is detected. Note that the above-described operation of turning off the external magnetic field includes a case where the external magnetic field is reduced to a level at which super-resolution does not substantially occur.

Next, in the step of determining the optimum recording light amount,
The optimum recording light amount is searched for from the recording states stored in the memory, and the optimum recording light amount is determined.

When the test write is completed, the optical pickup 2 is moved to the information recording area 12 in FIG. 2, and information can be recorded based on the optimum recording light amount. The recorded information is read at the time of the test read, and optimal control of the reproduction light amount can be performed. The test read operation will be described later.

The above operation will be described in more detail mainly with reference to the flowchart of FIG. When the test write is started by the test write operation command, the apparatus turns on the external magnetic field by the magnetic head 5 (S11). next,
An initial value of the recording light amount is set (S12), and a test pattern is magnetically modulated and recorded in a test write area of the magneto-optical disk 1 (S13). At this time, as shown in FIG. 9 (a), recording marks m1 to track T ₀ of the magneto-optical disc 1 is recorded. Next, turn off the external magnetic field (S14), it reproduces the track T ₀ (S15). Thus, the amplitude V _{0 of the} reproduced signal indicated by the solid line in FIG. 9D is detected (S1).
6).

The external magnetic field that is turned on in S11 is applied to write a test pattern on the magneto-optical disk 1. That is, the external magnetic field is
Unlike an external magnetic field Hex applied to generate an aperture on the reproduction layer 41 during reproduction, the magnetic field is controlled by a magnetic head drive signal d sent from the magnetic head drive circuit 21.

Subsequently, the external magnetic field is turned on again (S1).
7), erases the adjacent tracks T _1, as shown in FIG. 9 (b), followed by erasing the opposite adjacent track T _-1 (S1
8). Then, off the external magnetic field (S19), as shown in FIG. 9 (c), to reproduce the track T ₀ again (S20). Thus, the amplitude V ₁ of the reproduced signal shown by the broken line in FIG. 9 (d) is detected (S21). Note that S
The external magnetic field turned on at 17 is the magneto-optical disk 1
Is applied to erase the test pattern of the reproducing layer 4 while the direction and magnitude of the magnetic field are constant.
1 is different from the external magnetic field Hex provided for generating an aperture on the first magnetic field.

Here, if the recording light amount is too large, the spot area of the light spot p becomes large, and as shown in FIG. 9C, the recording mark m2 is smaller than the recording mark m1 before erasing. The side is erased. Therefore, the amplitude V ₁ was smaller than the amplitude V _0. Conversely, when the recording light amount is small, both sides of the recording mark m2 is because they are not erased, it is equal to the amplitude V ₀ and an amplitude V _1.

When the amplitude V _{1 of the} reproduced signal is detected, the external magnetic field (similar to the external magnetic field turned on in S11) is turned on again (S22). Then, to calculate the amplitude reduction ratio V ₀ -V _1, stores the amplitude reduction rate V ₀ -V ₁ and the recording light amount at this time in the memory (S23), the amount of light which the recording light quantity is predetermined It is determined whether or not the range is exceeded (S2
4). The if recording light amount does not exceed the amount of light a predetermined range (NO in S24), increases the quantity of recording light by a predetermined change amount (S25), the recording operation of the track T _0, i.e. returns to S13. In this way, until the recording light amount exceeds the predetermined light amount range (YES in S24), S
Steps S13 to S25 are repeatedly performed, and the memory stores each recording light amount and the corresponding amplitude reduction rate V ₀ −
V ₁ and is stored. If the set recording light amount exceeds the light amount range (YES in S24), an optimum recording light amount is selected from the recording light amounts stored in the memory,
(S26) The test write ends.

Here, the recording light amount and the amplitude reduction amount V ₀ -V ₁
The relationship between the S / N ratio and the S / N ratio will be described with reference to FIG. When the recording light amount is low, because as described above, both sides of the recording marks on the track T ₀ is not cleared, the amplitude reduction amount V
₀ -V ₁ falls within a range of detection error δV due to noise becomes almost zero. However, as the recording light amount is gradually increased, both sides of the recording mark begin to be erased at a certain recording light amount, and the amplitude decrease amount V ₀ −V ₁ starts to increase gradually.

[0060] In the recording light amount P _w0 just before immediately before the amplitude reduction amount V ₀ -V ₁ starts to increase, i.e., the amplitude reduction amount V ₀ -V ₁ exceeds the detection error .DELTA.V, the spot diameter of the light spot p the track Since the width is almost equal to the width, both sides of the recording mark are not erased, and the largest recording mark can be recorded. That is, at the optimum recording light amount P _w0 , the S / N ratio of the recording mark can be maximized. Therefore, in S26, the amplitude reduction amount V ₀ −V ₁ <δV, and the highest recording light amount is selected as the optimum recording light amount.

In the flowchart of FIG.
Storing amplitude V ₁ instead of amplitude reduction amount V ₀ -V ₁ in S23 step, it may be selected as the optimum recording light amount largest quantity of recording light amplitude V ₁ at step S26.

In the above description, the tracks T ₁ and T _1
Although both _-1 are erased, the same effect can be obtained by erasing only one of them. However, track T
_When both ₁ and T ₋₁ are deleted, the amplitude decrease amount V ₀ −V ₁ shown in FIG. 9D increases, and the detection sensitivity can be increased. In the above-described example, the magnetic field modulation recording is described. However, the present invention is not limited to this.

Further, in FIGS. 9A and 9C, when the external magnetic field Hex is turned off, the light spot p
The recording marks m1 and m2 are reproduced as a whole. Therefore, although the resolution is lower than in the case where the external magnetic field Hex is turned on and the information is reproduced by generating the super-resolution, the stable recording state which is not affected by the fluctuation of the environmental temperature or the like can be detected. Incidentally, regarding the decrease in resolution, the recording mark m1
By recording the test pattern so that the size of the light spot is equal to or larger than the diameter of the light spot, it is possible to compensate for a decrease in the S / N ratio due to a decrease in resolution.

In the test write described above, an example is shown in which the intensity of the recording magnetic field is optimized by fixing the external magnetic field strength during recording of the test pattern. In the above, the external magnetic field intensity may be increased instead of the recording light amount. Thereby, the intensity of the external magnetic field at the time of recording can be optimized. That is, FIG.
In order to simplify the explanation, the light spot p is shown by a complete circle, and the recording mark is transferred in the area irradiated with the light spot p. For example, it has a temperature distribution such as a Gaussian distribution, and the transfer area of the recording mark is determined by the temperature distribution of the light spot and the intensity of the external magnetic field. Therefore, even when the recording light amount is fixed, if the external magnetic field strength changes, the size of the recording mark also changes, and if the external magnetic field strength continues to increase, the amplitude decrease amount V ₀ -V ₁ turns from 0 to increase. A magnetic field strength occurs. Therefore, the optimum value of the external magnetic field strength at the time of recording can be obtained.

Subsequently, the operation of the test read in FIG. 7 will be described in detail below. At the time of test reading, first, based on the light amount control signal g from the control circuit 8,
The reproduction light amount of the light beam b is set. Next, the external magnetic field Hex
Is turned off to detect the level of the reproduction signal from the recording mark when super-resolution does not occur. Next, the external magnetic field Hex is turned on to generate super-resolution, and the reproduction signal level is detected. By comparing the reproduction signal level when the external magnetic field is on and off, the size of the aperture with respect to the light spot area can be measured, so that the amount of reproduction light can be controlled so as to have a predetermined aperture size.

The test read operation will be described in more detail mainly with reference to the flowchart of FIG. When a test read is started by a test read operation command,
The present apparatus first sets an initial value of the reproduction light amount (S3
1). Next, the external magnetic field Hex is turned off (S32), and the amplitude V _{0 of} the signal reproduced from the recording mark is detected (S32).
33). At this time, as shown in the left part of FIG. 12A, the recording mark is reproduced by the entire spot of the light spot p, and the amplitude V ₀ is indicated by a broken line in the left part of FIG. Obtained from the reproduced signal.

Next, the external magnetic field Hex is turned back on (S3
4), detects the amplitude V ₁ of the signal reproduced from the recording mark (S35). At this time, as shown in the right part of FIG. 12 (a), the recording marks on the magneto-optical disk 1 is reproduced by the aperture r indicated by the broken lines, said amplitude V ₁ was, right shown in FIG. 12 (b) Is obtained from the reproduced signal indicated by the broken line. Since the area of the aperture r is smaller than the spot area of the light spot p, the external magnetic field He
When x is turned on, the resolution is higher than when it is turned off. For this reason, the amplitude V ₁ is determined by the external magnetic field Hex.
Is slightly larger than the amplitude V ₀ obtained when the signal is turned off.

As described above, when the amplitudes V ₀ and V ₁ are detected, V ₁ / V ₀ is calculated, and it is determined from the V ₁ / V ₀ whether the current reproduction light amount is appropriate. (S36).
If it is determined that the reproduction light amount is not appropriate (N in S36)
O), the reproduction light amount is increased by a predetermined amount (S37), and S
Return to 32. Thus, steps S32 to S37 are repeated until it is determined that the reproduction light amount is appropriate (YES in S36).

Here, an example of the method of determining the reproduction light amount in S36 will be described. First, with reference to FIG. 12, a description will be given of a change in V ₁ / V ₀ with an increase in the reproduction light amount. When the reproduction light amount of the light spot p increases, when the external magnetic field Hex is turned off, the amplitude V _{0 of the} reproduction signal increases as indicated by the solid line in the left part of FIG. Next, when the external magnetic field Hex is turned on, the mask region in the high-temperature portion is expanded, and the area of the aperture r, which is the read portion, is reduced as shown by the solid line in the right portion of FIG. As a result, the resolution is further increased,
As shown by the solid line in the right part of (b), the amplitude V _{1 of the} reproduced signal increases.

Since the rate of increase of the amplitude V ₁ is greater than the rate of increase of the amplitude V ₀ , V ₁ increases as the amount of reproduced light increases.
/ V ₀ also increases. FIG. 13 shows the reproduction light amount of the light beam b,
FIG. 4 is a diagram showing the relationship between V ₁ / V ₀ and the S / N ratio of a reproduced signal. As described above, V ₁ / V ₀ gradually increases as the reproduction light amount of the light beam b increases. Also,
To increase the amplitude V ₁ of the reproduction signal initially, but increases as this is also the S / N ratio, the beginning gradually the temperature of the recording layer becomes small amplitude V ₁ on the contrary closer to the Curie point, S
The / N ratio starts to decrease. Therefore, there is a reproduction light amount _{Pr0 at} which the S / N ratio becomes maximum due to these _balances .
Assuming that V ₁ / V ₀ at this time is the reference value A, if the reproduction light amount is controlled in the test read so that the reference value A is obtained, the reproduction error can be reduced most.

That is, in step S36, V ₁ /
When V ₀ becomes substantially equal to the reference value A, it may be determined that the reproduction light amount is appropriate. Specifically, for example, V ₁ / V ₀ is compared with a preset reference value A, and the reproduction light amount when V ₁ / V ₀ first exceeds the reference value A is set as an appropriate reproduction light amount. Alternatively, a reference range centered on the reference value A is set in advance, and the reproduction light amount when V ₁ / V ₀ falls within the reference range is determined as an appropriate reproduction light amount. A method is conceivable.

If an appropriate amount of reproduced light is selected in step S36, the test reading is terminated, and the information recorded on the magneto-optical disk 1 is read with the light beam b of the amount of reproduced light.

It is to be noted that the optimization by the test read is not limited to the reproduction light amount. When optimizing the reproduction magnetic field intensity, the reproduction light amount is fixed and the reproduction signal amplitude is changed while changing the reproduction magnetic field intensity. Is detected. In other words, even if the reproducing light amount is constant, if the reproducing magnetic field intensity increases, the mask region in the high-temperature portion increases due to the influence of the temperature distribution of the light spot p and the reproducing magnetic field intensity, and the area of the aperture r decreases. . Therefore, increases resolution in the case of turning on the external magnetic field Hex, the amplitude V ₁ is increased, allows optimization of the reproducing magnetic field intensity.

In the test lead, the light spot p
By reproducing the mark m3 smaller than that, it is possible to detect a change in resolution when the external magnetic field is turned on / off. If the mark m3 is larger than the light spot p, a change in the resolution cannot be detected.

As described above, the recording / reproducing apparatus according to the present embodiment performs the test writing within a certain appropriate range during the test writing.
A specific recording condition, for example, a recording light amount or a recording magnetic field intensity is set, and a test pattern is recorded on the magneto-optical disk 1 under the recording condition. When reproducing the test pattern, since the external magnetic field Hex is turned off, the test pattern is not affected by the fluctuation of the environmental temperature or the disc.
The level of a reproduced signal obtained by this reproduction can be detected. The level of the reproduction signal is transmitted to the control circuit 8,
Stored in memory.

After changing the recording conditions by a predetermined amount and storing the levels of the reproduction signals corresponding to the plurality of recording conditions in the memory, the control circuit 8 compares the levels of the stored reproduction conditions. Then, the recording condition for recording the optimal reproduction signal is determined as the optimal recording condition.

As a result, it is possible to accurately determine the optimum recording conditions in the present apparatus without being affected by fluctuations in the environmental temperature and variations in the disks. Therefore, if recording is performed on the optical recording medium using these recording conditions, recording can be performed under optimal conditions, and information with few errors can be recorded.

Further, at this time, the test pattern is
If a pattern is used to form a recording mark larger than the spot diameter of the light beam b emitted from the optical pickup 2 to the magneto-optical disk 1, the resolution decreases when the external magnetic field Hex is turned off by the large recording mark. And the recording state can be detected by a high S / N ratio.

Further, the recording / reproducing apparatus according to the present embodiment performs, for example, a test within a certain appropriate range during a test read.
Under a specific reproducing condition, for example, a reproducing light amount or a reproducing magnetic field intensity, the recording is performed on the magneto-optical disk 1 in both a state where the external magnetic field Hex is applied and a state where the external magnetic field Hex is not applied. To play back the information.
By comparing the levels of the reproduction signals obtained by these reproductions, it is possible to detect a change in resolution due to the application of the external magnetic field Hex.

Then, while changing the reproduction conditions by a predetermined amount at a time and storing the comparison result of the levels of the reproduction signals corresponding to the plurality of reproduction conditions in the memory, the control circuit 8 sets the level of the stored reproduction conditions. From the results of the comparison, the reproduction condition for obtaining the optimum reproduction signal is determined as the optimum reproduction condition.

As a result, it is possible to accurately determine the optimum reproduction condition in the present apparatus without being affected by the fluctuation of the environmental temperature and the fluctuation of the disk. Therefore, if the reproduction of the optical recording medium is performed using the reproduction conditions, the reproduction can be performed under the optimum conditions, and the information with few errors can be reproduced.

Further, at the time of the reproduction, the optical pickup 2
Reproduces a recording mark smaller than the spot diameter of the light beam b irradiating the magneto-optical disk 1, and determines the reproducing condition based on the level of the reproduced signal. The resolution can be greatly changed from the case where no information is reproduced, and the reproduction light amount or the reproduction magnetic field intensity at the time of information reproduction can be controlled by a high S / N ratio.

The magneto-optical disk 1 used in this apparatus
Is not limited to that shown in FIG. 2, but as shown in FIG. 3, a test write area 11 may be provided at a periodic portion in the circumferential direction of the disk, and a test pattern dedicated to test write may be recorded in this area. . Further, in the test read, a mark smaller than the light spot in the recorded information was reproduced. However, the present invention is not limited to this. By replacing the periodic portion shown in FIG. Alternatively, a test lead pattern including a small mark may be recorded.

[0084]

As described above, the recording / reproducing apparatus according to the first aspect of the present invention comprises a recording unit for recording information on an optical recording medium, a reproducing unit for reproducing information on the optical recording medium, and an optical disc. Magnetic field applying means for applying an external magnetic field to the recording medium, reproduced signal detecting means for detecting a signal level of a reproduced signal obtained by reproduction by the reproducing means, and information on the optical recording medium by controlling the recording means When the information is reproduced by controlling the reproducing means and the signal level of the reproduced signal is detected by the reproduced signal detecting means, the external magnetic field is selectively applied at the time of reproducing the information. Control means for controlling the magnetic field applying means as described above.

Therefore, when information is read, that is, at the time of normal reproduction, by applying an external magnetic field, it is possible to generate an aperture in the reproduction layer of the optical recording medium to perform high-resolution reproduction. At the same time, information can be reproduced without applying an external magnetic field, and the level of the reproduced signal can be detected by the reproduced signal detecting means, so that reproduction can be performed without generating an aperture. In this case, there is an effect that the recording state of the recording mark on the optical recording medium can be detected without being affected by the fluctuation of the environmental temperature or the fluctuation of the disk.

The level of a reproduced signal when information is reproduced while applying an external magnetic field and the level of a reproduced signal when information is reproduced without applying an external magnetic field are detected. Is compared, the change in resolution from the reproduced signal can be accurately detected.

The recording / reproducing apparatus according to the second aspect of the present invention includes, in addition to the configuration of the first aspect, a test signal generating means for generating a test signal and a recording condition setting means for setting a recording condition. The control means controls the recording condition setting means to set a recording condition in the recording means, and controls the recording means to perform a test from a test signal generated by the test signal generation means on the optical recording medium. The pattern is recorded, and the test means is controlled to reproduce the test pattern without applying an external magnetic field. When the level of the reproduced signal obtained by the reproduction is detected by the reproduced signal detecting means, the reproduction is performed. In this configuration, the recording conditions are controlled based on the signal level to determine the optimum recording conditions.

Therefore, in addition to the effects of the configuration of claim 1, the optimum recording conditions in the recording / reproducing apparatus for performing reproduction by generating an aperture in the reproducing layer of the optical recording medium are determined by the change of the environmental temperature and the variation of the disc. Can be accurately obtained without being affected by Therefore, if recording is performed on the optical recording medium using these recording conditions, there is an effect that recording can be performed under optimal conditions.

According to a third aspect of the present invention, as described above, in addition to the configuration of the second aspect, the test pattern may include a spot diameter of a light beam irradiated on the optical recording medium by the reproducing means. This is a configuration that is a pattern that forms a recording mark larger than the recording mark.

Therefore, in addition to the effect of the configuration of claim 2, it is possible to compensate for a decrease in resolution when a large recording mark does not apply an external magnetic field, and to detect a recording state with a high S / N ratio. To play.

A recording / reproducing apparatus according to a fourth aspect of the present invention includes a reproducing condition setting means for setting a reproducing condition, in addition to the constitution of the first aspect, wherein the control means comprises the reproducing condition setting means. Controlling the reproducing condition to the reproducing means, controlling the reproducing means to reproduce information recorded on the optical recording medium in both a state where an external magnetic field is applied and a state where no external magnetic field is applied, When the level of the reproduction signal obtained by the reproduction is detected by the reproduction signal detecting means, the reproduction condition is controlled based on the level of the reproduction signal, and the optimum reproduction condition is obtained.

Therefore, in addition to the effect of the configuration of claim 1, when an external magnetic field is applied to the optical recording medium, that is, when reproduction is performed by generating an aperture smaller than the spot diameter of the light beam in the reproduction layer, Since the level of the reproduced signal is detected both in the case where no external magnetic field is applied, that is, in the case where reproduction is performed without generating an aperture in the reproduction layer, a change in resolution is obtained by comparing these levels. And it is possible to optimize the reproduction condition so that the comparison result becomes a predetermined value.

According to a fifth aspect of the present invention, as described above, in addition to the configuration of the fourth aspect, the reproducing means may further comprise a reproducing means for irradiating the optical recording medium with a spot diameter of the light beam. A smaller recording mark is reproduced, and the control means controls reproduction conditions based on the level of the reproduction signal.

Therefore, in addition to the effect of the configuration of the fourth aspect, the resolution between the case where the external magnetic field is applied and the case where the external magnetic field is not applied by the small recording mark can be largely changed, and the information reproduction can be performed by the high S / N ratio. There is an effect that the reproduction light amount or the reproduction magnetic field intensity at the time can be controlled.

[Brief description of the drawings]

FIG. 1 illustrates one embodiment of the present invention, and is a block diagram illustrating a configuration of a recording and reproducing device.

FIG. 2 is a perspective view showing a configuration of an optical recording medium used in the recording / reproducing apparatus.

FIG. 3 is a perspective view showing another example of the optical recording medium used in the recording / reproducing apparatus.

FIG. 4 is a block diagram showing a part of a configuration of a magnetic head driver and a laser driver in the recording / reproducing apparatus.

FIG. 5 is a block diagram illustrating a configuration of a reproduction signal detection circuit in the recording / reproduction device.

FIG. 6A is an explanatory view showing a reproducing operation when an external magnetic field is turned on in the recording / reproducing apparatus.
(B) is an explanatory diagram showing a reproducing operation when the external magnetic field is off.

FIG. 7 is a flowchart showing a flow of an operation of the recording / reproducing apparatus.

FIG. 8 is a flowchart showing a flow of an operation relating to a test write among operations of the recording / reproducing apparatus.

FIG. 9A is an explanatory diagram showing a state in which a recording mark is recorded on a track of the optical recording medium shown in FIG. 2, and FIG. FIG. 9 (c) is an explanatory diagram showing a state where the recording mark recorded on the track is reproduced, and FIG. 9 (d) is an explanatory diagram showing a state where the recording mark recorded on the track is reproduced. 9 is a graph showing signal level data obtained by the above.

10 is a graph showing the relationship between the recording light amount of the light beam, the amplitude reduction amount, and the S / N ratio obtained by controlling the recording conditions by the recording / reproducing apparatus shown in FIG.

FIG. 11 is a flowchart showing a flow of an operation relating to a test read among operations of the recording / reproducing apparatus.

FIG. 12A is an explanatory diagram showing how information recorded on the optical recording medium shown in FIG. 2 is reproduced, and FIG. 12B is obtained by the above reproduction. 5 is a graph showing signal level data.

FIG. 13 shows the reproduction light amount and V ₁ / V of the light beam obtained by controlling the reproduction conditions by the recording and reproduction apparatus shown in FIG.
₅ is a graph showing the relationship between ₀ and the S / N ratio.

[Description of Signs] 1 Magneto-optical disk (optical recording medium) 2 Optical pickup (recording / reproducing means) 4 Laser driver (recording / reproducing means) 5 Magnetic head (recording / magnetic field applying means) 6 Magnetic head driver ( Recording means) 7 Reproduction signal detection circuit (reproduction signal detection means) 8 Control circuit (control means / reproduction condition setting means / recording condition setting means) 9 Test signal generation circuit (test signal generation means) 41 Reproduction layer 42 Cutting layer 43 Recording layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoyasu Ikeya 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Inside Sharp Corporation (72) Inventor Akira Takahashi 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Inside Sharp Corporation (72) Inventor Hideaki Sato Inside 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Sharp Corporation

Claims (5)

[Claims] 1. A recording layer for recording a recording mark, a reproduction layer on which information magnetically recorded on the recording layer is transferred by an exchange coupling force via a cutting layer, and a recording layer when a light beam is irradiated. When an external magnetic field is applied to an optical recording medium having a multilayer structure including a cutting layer that cuts an exchange coupling force between the recording layer and the reproducing layer in a region where the temperature is equal to or higher than a predetermined temperature, the reproduction is performed. A recording / reproducing apparatus for recording / reproducing data by irradiating a layer with a light beam, a recording unit for recording information on an optical recording medium, a reproducing unit for reproducing information on the optical recording medium, and an optical recording medium Magnetic field applying means for applying an external magnetic field to the reproducing means; reproducing signal detecting means for detecting a signal level of a reproducing signal obtained by reproduction by the reproducing means; and controlling the recording means to record information on the optical recording medium. Above When the information is reproduced by controlling the means, and the signal level of the reproduced signal is detected by the reproduced signal detecting means, the magnetic field applying means is adapted to selectively apply the external magnetic field when reproducing the information. A recording / reproducing apparatus, comprising: control means for controlling the operation of the recording / reproducing apparatus. 2. A recording apparatus comprising: test signal generating means for generating a test signal; and recording condition setting means for setting a recording condition, wherein the control means controls the recording condition setting means to set a recording condition to the recording means. The test pattern is recorded from the test signal generated by the test signal generating means on the optical recording medium by controlling the recording means, and the test pattern is controlled by applying no external magnetic field by controlling the reproducing means. Reproducing, and when the level of the reproduction signal obtained by the reproduction is detected by the reproduction signal detecting means, the recording condition is controlled based on the level of the reproduction signal, and the optimum recording condition is obtained. Claim 1
The recording / reproducing apparatus as described in the above. 3. The recording / reproducing apparatus according to claim 2, wherein said test pattern is a pattern for forming a recording mark larger than a spot diameter of a light beam applied to said optical recording medium by said reproducing means. apparatus. 4. A reproduction condition setting means for setting reproduction conditions, wherein the control means controls the reproduction condition setting means to set reproduction conditions to the reproduction means, and controls the reproduction means to perform optical recording. The information recorded on the medium is reproduced both in a state where an external magnetic field is applied and in a state where no external magnetic field is applied, and when the level of a reproduction signal obtained by these reproductions is detected by the reproduction signal detecting means, 2. The recording / reproducing apparatus according to claim 1, wherein the reproducing condition is controlled based on the level of the reproduced signal to determine an optimal reproducing condition. 5. The reproduction means reproduces a recording mark smaller than a spot diameter of a light beam irradiated on the optical recording medium by the reproduction means, and the control means reproduces a recording mark based on a level of the reproduction signal. 5. The recording / reproducing apparatus according to claim 4, wherein conditions are controlled.