JP2002008280A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problems that, in reading a recorded pattern in a medium having no referential data previously recorded, a reading failure due to the recording pattern is not distinguished from failure in the reading process itself and this results in inaccurate judgment for reading. SOLUTION: A repeated pattern of long marks/spaces is recorded in the recording medium. When the reproducing power is varied without applying an external magnetic field, up the level at which the data in the recording layer are directly transferred to the reproducing layer, the power Pr2 as the lower limit to reproduce the data is determined. Then an external magnetic field is applied to reverse the directly transferred data in the reproducing layer, and superresolution reproduction is performed to determine the power Pr1 as the lower limit to detect the reproducing signals. The power Pr2, Pr1 and the reproducing power Pr are controlled to satisfy Pr1<=Pr<Pr2 in the optical disk device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus for writing or reading recorded information on or from a recording medium on a disk using a laser beam, and more particularly to a reproducing condition for reading by magnetic super-resolution. For accurate and quick control of the.

[0002]

2. Description of the Related Art In conventional magneto-optical recording, a magneto-optical recording system represented by the ISO standard is well known. In these magneto-optical recordings, a perpendicularly magnetized film, which is vacuum-deposited on a transparent substrate of a recording medium, is irradiated with laser light, the temperature of the perpendicularly magnetized film is raised to the Curie point, and an external magnetic field is applied. Recording is performed by orienting the perpendicular magnetization film in the direction. The recording density at this time is determined by the temperature distribution due to the laser light spot irradiated on the perpendicular magnetization film, that is, the size of the region having the temperature distribution equal to or higher than the Curie point. For this reason, it is usually impossible to form a recording portion smaller than the laser spot diameter, and the recording density has been improved by reducing the laser beam spot diameter.

On the other hand, a so-called "mark" or "mark" is recorded by giving information to both ends (edges) of one pit, instead of giving information of "1" and "0" to one pit. Edge recording is known in magneto-optical recording. In the mark edge recording, the recording density can be improved, but in order to maintain the reliability of the information, it is necessary that the edge having the information is formed accurately. For this reason, when magneto-optical recording is performed by the normal mark edge recording, the recording power is previously applied to a test track (a track is an area on an optical disc where recording spots for recording information are arranged in a circle). It is necessary to perform so-called trial writing, in which the optimum recording power is obtained by changing (in this case, using a laser having a lower power than usual) and performing recording.

In recent years, the irradiation intensity and timing of laser light have been divided into a plurality of stages, and the thermal diffusion coefficient of a recording medium has been changed, so that only magnetic domain regions smaller than the minimum spot diameter of laser light have been reduced. It is possible to perform so-called “brush writing”, in which recording is performed with the temperature raised above the Curie point. At this time, at the time of reading after recording, in order to read a magnetic domain region recorded smaller than the spot diameter of the laser beam, it is necessary to use a magnetic super-resolution (hereinafter referred to as MSR).
A technique called ") is required. MSR refers to the thermal characteristics of the intermediate layer (such as the Curie point) when a reproducing layer is provided on a magnetic film for recording (hereinafter, referred to as a recording layer) via an intermediate layer and is irradiated with a laser to perform reproduction. Change
By applying an external magnetic field, the area of the recording layer where information is transferred is limited (masked). Further, by masking only a part of the laser read spot (a part where the laser read spot is larger than the recorded spot), the magnetic domain orientation of the recording layer in a region smaller than the laser spot is masked. Is transferred to the reproducing layer and reproduced. The area where the information on the recording layer is transferred to and read from the reproducing layer (hereinafter referred to as aperture) is determined by the relationship between the laser spot and the mask area.
Aperture Detection), CAD (Center Aperture Dete
ction) and RAD (Rear Aperture Detection). In a recording / reproducing apparatus using an MSR,
If the mask is not formed correctly, it is not possible to perform appropriate reading. For this reason, in the MSR method, so-called trial reading is required to find the optimum reproducing power. At this time, a problem arises in that the test reading is required in the MSR as described above, but the test reading requires reference recording data in advance. However, at the stage where the test write operation is not performed, when the recording data serving as the reference is recorded, the recording power is not optimized, so that the poor signal quality of the recording data itself is caused by the test reading. In some cases, the recognition result was incorrectly recognized. Or,
In some cases, test recording cannot be performed due to improper recording power, and test reading cannot be performed. There was a problem that it was not possible to recognize or read the test writing information.

To cope with this problem, Japanese Unexamined Patent Publication No. Hei 10-31
No. 2593, the information recording area IA (Information
Area), a recording condition control area OA (Operation Area)
Is proposed, in which the recording control area has a film configuration that does not cause magnetic super-resolution, performs a test writing operation in the OA, and performs a test reading in the IA after the test writing is completed. .

Japanese Patent Application Laid-Open No. H11-25537 discloses that, among magnetic super-resolutions, especially in magnetic super-resolution by the FAD method, a mask region is not formed in a state where the intensity of laser light is low. The laser spot diameter = aperture, and using a pattern larger than the spot diameter for test writing, performs a test writing that is not affected by magnetic super-resolution, and then performs a test reading later. I have. Further, JP-A-11-6659
In Japanese Unexamined Patent Publication No. 6 (1999), when parameters related to reproduction are not described in advance on the recording medium, recording is performed with provisional power, test reading is performed, and then each parameter is determined. Record
In the next initialization, first, the test track is accessed, information is read, and the process is terminated early.

In recent years, in the 90 mm 1.3 GB magneto-optical recording standard (GIGAMO standard) proposed by Fujitsu Laboratories Ltd.-Sony Corporation, signals are read out using MSR reproduction by the D-RAD method. ing. FIG. 18 shows an aperture formation state in the D-RAD method. As shown in FIG. 18, the D-RAD system is an improved version of the RAD system mentioned above, in which a front low-temperature portion of a light spot is masked under temperature conditions to form a rear aperture. In a high temperature state, the mask is formed due to the influence of the externally applied magnetic field.

[0008]

In the prior art, for example, in a recording medium disclosed in Japanese Patent Application Laid-Open No. 10-31593, it is necessary to perform a process operation of specifying a deposition portion or changing a film pressure for some films. As a result, the cost of producing the media has become enormous. Further, if the above operation is further added to the deposition of a multilayer film, which is considered difficult, the production yield is deteriorated, which is not suitable for practical use.

In Japanese Patent Application Laid-Open No. H11-25537, a FAD type MSR medium is used. At low reproduction power, only an aperture is formed and a mask is not formed. In a medium of the -RAD method, only a mask is formed in a low temperature part, and signal detection is impossible. Therefore, this technique cannot be used in the D-RAD method.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 11-66596, as described above, when reference data is not described in advance, a pattern to be recorded for test reading is truly recorded. Since it is not guaranteed that recording is performed at the optimum power, there is a problem in that in reading, a reading defect caused by a recording pattern and a defect in the reading itself cannot be separated, and reading judgment becomes inaccurate.

The present invention has been made in view of the above problems, and has been developed in consideration of
It is an object of the present invention to quickly perform an accurate test reading operation without requiring a special manufacturing method for a standard MSR recording medium, particularly for a medium.

[0012]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
In addition, the optical disc device of the present invention uses a laser
Optical disc drive that reproduces by irradiating light
The recording medium has a long mark / space repetition pattern.
The recording layer is recorded on the reproducing layer without applying an external magnetic field.
When the data is changed to the reproduction power for direct transfer
Of the reproducible minimum power of P_r2And then external
Applying a magnetic field restores the direct transfer of the reproduction layer, and performs super-resolution reproduction
The lower limit power for detecting the reproduced signal is P_r1And re
Raw power P _r, The constant γ is P_r1Multiplied by P_r= Γ × P
_r1(Γ ≧ 1) or P_r1And P_{r 2}Subdivided point P with_r
= AP_{r1 + B}P_r2(However, a <1, b <1 and
a + b = 1), and P_{r1 ≤}P_{r <}P_r2Tona
The reproduction power is set to a certain value.

Further, after the recording medium is inserted, the data written on the test track is used for setting the first reproduction power of the reproduction power, and the reproduction power for the second and subsequent times after the recording medium is inserted is used. It is characterized by setting.

Further, the present invention is characterized in that a long mark / space repetition pattern is used as a pattern used for obtaining reproduction power by direct transfer to a reproduction layer when no external magnetic field is applied.

A step of recording a repetitive pattern of long marks / spaces on the recording medium and varying the reproducing power to a level for directly transferring data of the recording layer to the reproducing layer without applying an external magnetic field; In the step of lowering and applying an external magnetic field to restore the direct transfer of the reproducing layer, the method is characterized in that the magnetic field strength required for MSR reproduction is confirmed or calculated.

According to the optical disk apparatus having the above-described configuration, it is possible to guarantee that a recording signal exists in an area where an appropriate reproducing power is required in a medium such as GIGAMO, and thereby it is possible to optimize the reproducing power. In addition, it is possible to accurately determine the recording power after that.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, one embodiment of the present invention will be described.
This will be described with reference to the drawings. In all the drawings, common parts are denoted by common reference numerals.

First, FIG. 1 is a schematic diagram of an optical disk device according to the present embodiment, and FIG. 2 is a diagram showing whether a test track is to be erased depending on the state of the disk when performing a test read in the optical disk device according to the present embodiment. Is shown. FIG. 3 shows a flowchart for writing a reproduction pattern on the test track and directly detecting the transfer reproduction power on the test track. FIG. 4 shows a method for lowering the reproduction intensity until the mask is formed.
5 shows a flowchart for changing a reproducing magnetic field. FIG. 5 shows a flowchart for performing MSR reproduction and detecting a reproduction start power and an optimum reproduction power, and FIG. 6 shows a flowchart for detecting a writing start sensitivity. FIG. 7 shows a flowchart for calculating the recording power based on the write start sensitivity, and FIG. 8 shows a flowchart for verifying the test reading and test writing sequence. FIG. 9 shows a processing flowchart of only the test reading, and FIG. 10 shows a GIGAM when the reproducing power is changed with or without applying the reproducing magnetic field.
4 shows the C / N characteristics of the O medium. FIG.
FIG. 12 shows a track layout of an IGAMO disk, and FIG. 12 shows a data RF signal. FIG.
3 to 16 show the DR when the reproducing magnetic field and the reproducing intensity were changed.
FIG. 17 shows the orientation of each magnetic domain of the intermediate layer of the AD medium and the perpendicular magnetic film of the reproducing layer. FIG. 17 shows the fluctuation of the reproducing signal due to the change of the reproducing magnetic field when the reproducing intensity is high and when the reproducing intensity is low. ing.

First, referring to FIG.
When reading information while the optical disc 12 is inserted into the optical disc 1, the CPU 1k gives the reproducing laser power intensity information to the reproducing laser intensity controller 1f which controls the intensity of the reproducing laser power. Based on this intensity information, the LD driver 1b is instructed how much current should flow through the LD. The intensity of the laser light emitted from the LD 19 can be arbitrarily changed depending on the current amount of the LD driver. The variable intensity reproduction laser light emitted from the LD 19 is reflected by the rising mirror 17 in the separated optical head 15 via the beam splitter 18, and is condensed and irradiated on the optical disk 12 by the objective optical system 16. . The optical head can be driven in a one-dimensional direction by a spindle motor (not shown) in parallel with the rotating optical disk, and can focus the reproduction laser light on an arbitrary portion in the optical disk surface. When a reproducing magnetic field is required at the time of reproducing, the magnetic field intensity information is given from the CPU 1k to the magnetic field intensity control unit 1j, and the bias generator 14 generates a magnetic field. The reproduction light reflected from the optical disk surface passes through the objective optical system 16 again, is reflected by the mirror 17, is split by the beam splitter 18, and is detected by the photodetector 1a. The detected reproduction signal is processed by the reproduction signal processing unit 1g as information corresponding to the signal strength,
It is converted into data and transmitted to the CPU 1k. When recording information in the optical disk device 11, the CPU 1
k, the recording laser power intensity information is given to the recording intensity control unit 1e via the recording signal processing unit 1d.
Gives an instruction on how much current flows to the LD driver 1b. Further, the recording signal processing unit 1d receives the information of the recording signal from the CPU 1k, generates a pulse light emission pattern in accordance with the actual recording signal, and causes the LD to pulse emit light at the above intensity. The reproduction intensity at the time of performing the so-called test reading when the reproduction intensity is variously changed via the reproduction intensity control unit 1f according to the instruction of the CPU 1k is stored in the read power storage means 1h which is a RAM. Further, the read magnetic field strength when the test reading by so-called magnetic field change when the magnetic field strength is variously changed via the magnetic field strength control unit 1j according to the instruction of the CPU is stored in the read magnetic field storage means 1i which is a RAM. Is done. In addition, the CPU described above is, for example, S
It is connected to and controlled by a host computer 13 via a CSII / F (squay interface) 11.

Next, this embodiment will be described with reference to the flowcharts shown in FIG. When performing the test reading according to the present invention, a TEST ZONE hesitation of Band 0 (see FIG. 11) is performed according to the flowchart processing of FIG. 2 (step 31). At this time, it is determined whether or not the disk has just been inserted (step 32), and if not, the process immediately proceeds to the processing in FIG. If it is determined that the disc has just been inserted, first TEST ZO
Erasing the sector used for test reading among the NEs at a fixed power (step 33). The erase power at this time may be a power that has been previously confirmed to be erasable for each temperature, or may be an upper limit power set in the drive. After that, when performing the test reading, the sector position used for the test reading is reset. Here, a variable called Sctcount is set as a parameter indicating the sector position, and Sctcount = 0 is set (Step 3).
4), the process proceeds to the process of FIG.

A loop for measuring the reproduction direct transfer power on the GIGAMO medium shown in FIG. 3 will be described below. First, a 6T-length continuous pattern (33 patterns) is recorded at a fixed power in 1 SCT in the TEST ZONE (this is a sector in which the number of sectors is shifted by Sctcount from the start sector of the TEST ZONE) (step 4).
1). The continuous pattern of 6T length at this time may be any pattern as long as long marks / spaces are repeated (for example, 8T continuous pattern). Further, the fixed power at this time uses the same fixed power as the erase power. Since this 6T continuous pattern is a repetitive signal of a long mark / space, there is no interference between marks in reading even if the spot diameter is large, and the signal quality does not decrease even if the power is over the optimum recording power. almost none. Thereafter, the reproducing power when no reproducing magnetic field is applied (hereinafter referred to as P _rn ) is set to a fixed value (step 42). The fixed value at this time may be a fixed value recorded in the CPU in advance, or may refer to a parameter table in consideration of a temperature characteristic, a medium reproduction position, and the like for shortening the sequence. The 6T continuous pattern recorded in step 41 is reproduced with the reproduction power (step 43). The upper and lower envelope peak values (pp values) of the RF signal in the DATA section of the reproduced signal are sampled and held (step 4).
4), fetch the signal amplitude value (step 45). In capturing the amplitude value at this time, the rising of the signal is monitored by analog-to-digital conversion.

Here, an outline of the RF signal is shown in FIG. The magnitude of the actual signal amplitude of the RF signal is obtained from the difference between the upper and lower limits of the envelope, and this is used as the RF signal.

Returning to FIG. 3, it is determined whether the detected amplitude value satisfies a reference value or more. In this case, the criterion is 320 mV (step 46). In the determination of the amplitude value, if the above criterion is satisfied, the process proceeds to step 47 and subsequent steps. First, the processing when the determination criteria are satisfied will be described. When the amplitude value satisfies the determination criterion, since the reproduction is performed in a state where the external magnetic field is not applied to the MSR medium, the MSR reproduction is not performed. In this case, the reproduction signal is detected because the reproduction intensity is much higher than the MSR reproduction power, and the pattern of the recording layer is directly transferred to the reproduction layer. For example, FIG. 10 shows a change in the amplitude of the reproduction signal amplitude at the reproduction power when a reproduction magnetic field is applied / not applied to a GIGAMO medium or the like. When a reproducing magnetic field is not applied, a reproducing signal cannot be read until the reproduction signal is directly transferred to the reproducing layer. Therefore, a reproducing power larger than the MSR reproducing power is required.

Further, the reproduction power P _rn when no reproduction magnetic field is applied is stored in the CPU as the reproduction upper limit power P _r2 (step 47), and the flow shifts to the processing shown in FIG.

Next, a description will be given of a sequence process performed when the determination condition is not satisfied in the amplitude determination in step 46. When the amplitude determination condition is not satisfied in the step 46, the reproducing power is increased on the assumption that the reproducing power is less than the strength for directly transferring the recording pattern to the reproducing layer (step 48). An arbitrary value can be selected for the step of increase at this time, but here, it is assumed to be 0.1 mW. If an excessively large value (abnormal value) is set in the increase of the reproduction power, adverse effects such as deterioration of the characteristics of the medium, loss of the recording pattern, and destruction of the medium may occur.
Therefore, in the next step 49, an upper limit of the reproducing power is set so that the reproducing power is not set to a value higher than this value. For example, in step 49, the reproduction power is not set to 8 mW or more as the temporary upper limit.
If the reproduction power is lower than the upper limit, the operation is repeated from the sequence of step 43. If the upper limit is exceeded in step 49, the test read sector is shifted. Here, the Sctcount set in the previous step 34 is used. If the shift amount of the test reading sector exceeds a certain value, an abnormality that does not depend on the sector itself, that is, a drive abnormality is considered in this case, so it is determined whether or not the drive is abnormal at a certain upper limit (step 4a). Here, the determination value is assumed to be 3 (sector). If the determination condition in step 4a is exceeded, an abnormality that does not depend on the sector for performing the test reading,
That is, the process ends as a read power setting error (step 4b). If the sector shift amount does not exceed the upper limit, there may be a defect due to the sector that was trying to perform these sequences, so the sector shift amount, here Sctcount, is incremented by 1 and the sequence is repeated (step 4c). That is, in this flowchart, retry is performed from step 41 described above.

Next, a further sequence shown in FIG.
Will be described. In the sequence, the playback power is set to MSR
Playback is not possible, and the focus and track servo are off.
Reduce to a size that is not enough. Here, the provisional value is 1.4.
mW (step 51). And externally applied magnetic field
Is applied in the write direction (step 52). Applied magnetism
The field strength is applied at an initial fixed value. Reduce playback power
When a sufficient reproducing magnetic field is applied, the GIGAMO medium
Only the mask is formed and the aperture does not open. However
Even if the read power is lowered, a sufficient read magnetic field is applied.
If not, the recording pattern directly transferred to the reproduction layer
It is not masked by the raw magnetic field and detected as a signal with amplitude.
Will be issued. The detection of the magnetic field strength at this time is not shown.
Intensity detection using a Hall element may be
Current flowing in the bias generator shown at 14 of 1
The amount may be monitored. Here, the signal detection condition is assumed to be 1
Assuming that the amplitude of the RF signal is 70 mV,
V) It is determined whether it is less than or equal to (Step 53).
In this case, it is assumed that the mask has been formed by applying an external magnetic field.
Multiply the current magnetic field strength by one or more constants,
Stored in CPU as strength
You. The one or more constants are previously determined as the temperature rise rate of the optical drive.
The magnetic field strength of the bias coil decreases due to temperature rise.
Set a value that includes a small percentage as a margin. This step
The drive temperature stored in step 54 is used in subsequent processing.
If a large fluctuation in drive temperature is observed,
Power P _r2Is multiplied by a correction coefficient, and a new P_r2Calculate
I do.

Next, a description will be given of a sequence process performed when the determination condition is not satisfied in the amplitude determination in step 53. If the amplitude determination condition is not satisfied in step 53, the reproducing magnetic field is increased (step 55), assuming that the reproducing magnetic field intensity is less than the intensity for masking the reproducing layer. At this time, an arbitrary value can be selected for the step of ascending, but here, it is tentatively set to 10 [0e]. If an excessively large value (abnormal value) is set in the rise of the reproducing magnetic field, adverse effects such as excessive power consumption of the optical disk device or a sudden rise in temperature of the optical disk device may be caused. Therefore, in the sequence of FIG. 4, in step 56, an upper limit of the reproducing magnetic field is set so that the reproducing power is not set to a value higher than this value. When the reproduction power is lower than the upper limit, the operation is repeated from the sequence of step 53. By setting the upper limit in step 56,
If the value exceeds the upper limit, the test reading sector is shifted. Here, the Sctcou set in the previous step 34
Use nt. If the shift amount of the read sector exceeds a certain value, an abnormality not due to the sector itself, in this case, a drive error is considered, so it is determined whether or not the drive is abnormal at a certain upper limit (step 57).
Here, the determination value is assumed to be 3 (sector). If the determination condition in step 57 is exceeded, the process is terminated as an abnormality that does not depend on the sector in which the test reading is performed, that is, a reproduction magnetic field setting error (step 58). If the sector shift amount does not exceed the upper limit, there may be a defect due to the sector that was trying to perform these sequences, so 1 is added to the sector shift amount, here Sctcout, and the sequence is repeated. In this flowchart, retry is performed from the sequence shown in FIG.

Next, FIG. 5 will be described. FIG. 5 is a flowchart of the actual test reading after setting various conditions necessary for the test reading in the flowcharts of FIGS.
FIG. 4 is a flowchart of a test reading in a case where it is determined that the processing in step 4a is normally completed in FIG. here,
It is guaranteed that the test read judgment pattern is already recorded on the test track, and the external applied magnetic field is also
5 is a flowchart of a test reading in a state where it is guaranteed that a magnetic field having a strength enough to form a mask is applied in MSR reproduction. Hereinafter, each item will be described in detail.

In the sequence flowchart, first, an external magnetic field is applied (step 61). This applies a magnetic field equivalent to the magnetic field strength that can mask the direct transfer of the reproducing layer in the flowchart of FIG. Even when the disk is not inserted immediately, the applied magnetic field confirmed in the sequence when the disk is inserted for the first time is used. After that, the upper and lower limits of the reproduction power are initialized (step 62). As described in the flowchart of FIG. 3, the upper limit of the reproduction power must be smaller than the power directly transferred to the reproduction layer, and is therefore defined by _Pr2 in (step 47). In this flowchart, the MSR regeneration lower limit _Pr1
However, since the value is undecided, P _r1 is initially set as a provisional value.
_{Is the} same size as _Pr2 . Thereafter, the initial read power for test reading is set (step 63). In order to distinguish the currently set reproduction power from the others, here P
_rn . Here, an arbitrary power smaller than the upper limit power _Pr2 can be selected as the reproduction power of the test reading initial setting. However, in order to reduce the number of rotations of the loop described below, an expected power that is considered to be close to the reproduction lower limit is selected. It is better to do.

A description will now be given of a sequence for adjusting the reproduction power of the test reading. First, by the operation of FIGS. 2 to 5, a sector (reference sector + S
ctcount) is read at the set reproduction power (step 64). Then, the envelope peak value of the RF signal in the DATA signal SB portion of the reproduced signal is sampled and held, and it is checked whether or not a signal is detected in the reproduced signal data portion (step 65). The sampled and held peak-to-peak signal is ADRDEN signal, and the rising signal is A / D converted and taken in (step 66).
The monitored RF amplitude value is used as a determination condition. Here, the judgment condition is 3 which is about half of the saturation amplitude value.
20 mV was used as a provisional value (step 67). If the amplitude is detected under these determination conditions, it is assumed that the MSR has been reproduced, and the processing from step 68 onward is performed.

Here, the processing routine when the amplitude cannot be detected first will be described. If no RF signal is detected, it is determined that the intensity of the reproduction power P _rn is low,
The intensity of _rn is increased by one step (step 6d). Here, the temporary value of the above step is 0.1 mW and 0.1 mW
Is rising. Further, as a check of the upper and lower limits of the MSR reproduction, the newly set reproduction power P _rn is compared with the upper limit power _{Pr 2} (step 6e). P _rn is _{Pr 2}
If it is larger than _{Pr 2} , since _{Pr 2} has a large power enough to directly transfer to the reproducing layer even without an externally applied magnetic field, P _rn does not exceed it, and there is an abnormality in the light emitting state of the drive. As a matter of fact, the process ends with a read power setting error (step 6f). If P _rn is smaller than P _r2 , the process returns to the sequence of step 64 again to determine the amplitude of the reproduced signal.

Further, when succeeding in amplitude detection of the RF signal, and compares the reproduction limit power _{P r1} and the reproduction power _{P r n} currently set (step 68). Since the reproducing limit power P _{r 1} are equal to the upper limit power P _r2 initially a large power enough. Further, P _rn and P
_In comparison with _r1 (step 69), P _rn becomes P _r
The processing when the value is less than ₁ will be described first. In this case, the MSR
To say renewable further lower power is detected, and, the lower limit power P _r1 equal to the P _rn (step 6 g). Further, in order to determine whether or not there is a smaller reproduction power capable of performing the MSR reproduction, the reproduction power P
_rn is lowered by one step (0.1 mW) (step 6
h), it is determined whether the reproduction power P _rn does not fall below the reproduction lower limit (step 6i). The reproduction power fixed lower limit here may be a reproduction power that does not necessarily require the MSR or may be 0 mW in the preliminary study. Here, 2.0 mW is used as the provisional value. If _Prn is below the fixed lower limit of the reproduction power by the operation in the step 6h, it is determined that the reproduction power setting has not been properly performed, and the read power setting processing error is processed (step 6j). If the value is not below the fixed lower limit of the reproduction power, the sequence returns to the step 64 and the reproduction signal detection loop is repeated.

On the other hand, the condition of step 69 is satisfied.
In this case, the MSR reproduction lower limit power P _r1Is also set
Turn off the externally applied magnetic field (step 6a), and
The power is set (step 6b). Setting the playback power
The parameter used for the determination is the MSR playback lower limit power.
P_r1, MSR playback upper limit P_r2Use one of
For example, take the average of both, or a certain ratio of both
A subdivision point in the rate may be specified. Here, advance
Specify one or more constants γ based on the consideration, and set the lower limit P_r1To
Multiply. After that, set playback power P_rIs the upper and lower limit
(P_r1≤P_r<P_r2)
Recognition is performed (step 6c). Here, P_r1 for setting
The above constant γ is P_r1Is multiplied by
P_rIs P_r2And judge only if it is smaller than
I have. At this time, P_rIs the upper limit power P_r2Exceeds
Then, as a read power setting error (step 6k)
The process ends. Further, in step 6c, the reproduction
Word P_rAfter setting, whether or not the disc has just been inserted again
A branch is set (step 61). Immediately after inserting the disc
If so, the flowchart shown in FIG.
If it is not immediately after inserting the disk, the flowchart shown in FIG.
Move on to chart processing.

Next, the flowchart shown in FIG. 6 will be described. Here, as a series of actions immediately after the insertion of the disc, a test writing process immediately after the end of the test reading is performed.

Although not described in the flowchart below, as the reproducing power for performing the following operation, the reproducing power set in the flowchart of FIG. 5 is used. First, in order to use the sector used in (1) in retrying the test reading later, the test writing sector is shifted from the used sector to the next sector before the start of the test writing (step 71).
Here, it is temporarily shifted by one sector and performed in an adjacent sector. The sector after the currently accessed sector is erased with fixed power (step 72). The erasing power at this time is always set to the erasable power stored in the memory of the CPU in advance, similarly to the processing of step 53 in FIG.

The test writing loop will be described below. First, a test write is performed on the currently accessed sector (step 73). At this time, a fixed power may be selected as the initial value of the test write power.In order to shorten the convergence time, the power expected to be close to the result of the test writing is stored in a table, and if necessary, May be referred to. Further, in the flowchart of FIG. 4, test writing by PWM ternary recording is taken as an example, and the ratio of ternary power at this time is fixed.
The test write may be performed by varying each power.

Next, read the recording signal (step 74).
Thereafter, the envelope peak value of the RF signal in the DATA signal SB is sampled and held, and it is checked whether or not a signal is detected in the reproduced signal data (step 75). The sampled and held peak-to-peak signal is ADRDEN signal, and the rising signal is A / D converted and taken in (step 76). The monitored RF amplitude value is used as a determination condition. Here, as the determination condition of the recording signal, the determination is made by evaluating the characteristic at which the amplitude starts to be saturated. As shown in FIG. 10, the recording signal amplitude due to the recording power shows a tendency for the amplitude value to increase sharply in a narrow power region. In the embodiment of the present invention, the saturation recording signal is approximately 600
mV, which is around 30 to 50 mV during non-recording, and the condition for judging the point where the amplitude value becomes steep is 320 mV. First, in the present embodiment, a detection margin is given as a condition for determining whether or not an amplitude is detected.
The determination is made based on whether the voltage is equal to or more than mV (step 77).

If the signal amplitude is equal to or greater than the predetermined value, it is determined that a signal has been detected, and the process proceeds to the next step 78. Here, the processing when the amplitude is not detected will be described first. That is, when the signal amplitude is not detected, the sector is moved to the sector next to the sector and the write power (write output) is increased to perform the write (step 7).
9). The step of changing the write power at this time is
A slightly larger power is used as a rough adjustment. Here, 0.3 mW is used as a provisional value. Thereafter, an upper limit power is set and a determination is made so that the write power is too large and the LD 19 mounted on the drive is not destroyed. Here, the upper limit power is set to 15 mW (step 7).
a). If the determination condition in step 7a is exceeded, the process ends as a write power setting error (step 7b). If it is within the determination conditions, the process from step 76 is retried.

Next, processing when a recording signal is confirmed will be described. In the same manner as in step 77, a detection margin is set, and a determination is made at 470 mV or less (step 7).
8). Next, a loop when the determination condition is not satisfied will be described first. If the signal amplitude is equal to or less than the above value, it is determined that the recording power is saturated, and the next sector is moved to and the write power is reduced to perform the write (step 7c). In this step, the same 0.3 mW as in step 79 is used. Again, a lower limit of the write power is provided to prevent unnecessary wasting of test writing time (step 7).
d). Here, the lower limit of the write power is 3 mW. The lower limit may be determined based on a minimum value obtained by comparison with the reproduction lower limit power _Pr2 used in the processing of FIG. If the write power falls below this lower limit, the process is stopped and a write power setting error is returned (step 7e). If it is within the judgment condition, the above step 7
Retry the process from 6.

When the determination conditions of the steps 77 and 78 are satisfied, the determinations of the steps 7f and 7g are performed in order to obtain a more accurate test writing power. That is, the step 7f further increases the 100 mV determination condition compared to the step 77 and makes a determination at 270 mV.
Decreasing the 0 mV judgment condition and making a judgment at 370 mV,
In addition, the power to be adjusted in the loop is made finer to increase accuracy. Here, the step is set to 0.1 mW.

When the judgment condition of step 7f is satisfied, it is further confirmed whether the judgment result is correct.
Here, write to the next sector with the same write power,
The peak value is captured by A / D (step 7h), and it is determined whether or not the difference from the signal amplitude recorded in the previous sector is within 150 mV (step 7o). If the above-mentioned determination condition is satisfied, the process proceeds to the step, and if not, the process moves to the next sector (step 7p). If the determination condition is not satisfied and the system moves to the next sector, it is confirmed whether or not all the sectors on the test track have been used (step 7q). If all the sectors on the test track have been used, the process ends as a write power setting error (step 7r). If not, the process from step 76 is retried.

Before explaining the processing routine of FIG. 7, FIG. 11 shows a track layout of a GIGAMO disk. As shown in FIG.
0, Band1,... Band16, Band17 and Band are arranged, and Test Z is assigned to each band.
one is arranged. Based on this, the processing routine shown in FIG. 7 will be described.

Since the write power at the start of writing is obtained in the first flowchart, the write power is determined by multiplying the write power by a constant (step 81).
Here, the value of the constant multiple is β. β is the disk B
A matrix table is prepared according to the operating temperature of the and and the drive, and is determined by reading from the matrix table as needed. When the write power is equal to or higher than the upper limit power (when test writing is determined), the upper limit power is set (step 82). Further, it is confirmed whether or not both the set write power and read power are correct, whether erasure / recording / reproduction is performed in the last sector where the RF peak value is measured, and whether or not the operation is normally completed (step 83). At this time, it is desirable to use, for example, a repetition pattern of a short mark / space and a long mark / space, etc. as the recording pattern. After confirming that the above operation is completed normally, the same operation as before is performed at Band 16 (step 84). Thereafter, the read power / write power determined by Band 0 and the read power / write power determined by Band 16 are respectively approximated by a straight line to determine the read power / write power of each Band (step 85). In addition, in the routine, the linear power approximation of two bands is used to determine the read power / write power of each band. However, in order to improve the accuracy of the read power / write power, three bands or more are used. May be used. After the read power / write power of each band is determined, the process proceeds to the flowchart of FIG. Also, the determined read power of each band /
The write power is stored in the read power storage unit 1h in FIG. 1, and is read out and used as needed under the control of the CPU 1k.

Next, the flowchart of FIG. 8 will be described. After the calculation is completed, the process moves to the sector used for the test reading of Band 16 again (step 91). Since the data pattern used for test reading remains in this portion, the upper and lower envelope peak values of the RF signal in the DATA portion of the reproduced signal are sampled and held, and the signal amplitude value is captured (step 92). It is determined whether or not it has been performed (step 93). In this case, since a 6T continuous pattern is used, if the amplitude value determination condition is 80
0 mV. When the determination condition of the reproduction signal is not satisfied (step 96), the processing shifts to the following processing. In this case, first, the gain of the read IC for detecting the reproduction signal is adjusted (step 96). So that the playback signal is within the desired value,
When the amplitude is large, the gain is decreased, and when the amplitude is small, the gain is increased. When the gain register is changed, it is determined whether the register set value has exceeded the upper limit or the lower limit (step 97). If the upper limit or the lower limit is not exceeded in this determination, the processing from step 92 is retried. If the register exceeds the upper or lower limit,
Since there is a possibility that the medium or the read IC is abnormal, it moves to the next sector (step 98). At this time, it is determined whether all the sectors in the test zone have been used (step 99). If all the sectors have been used, the process ends as a test read / write setting error (step 9c). Otherwise, a 6T continuous pattern is recorded in the next sector, and the process of step 92 is retried again. If the determination condition of step 93 is satisfied, writing is performed in the next sector with the current write power, and the peak value is captured (step 94). The difference between the peak amplitude in step 92 and the peak amplitude in step 94 is 100 m.
V is determined (step 95).
If the determination condition is not satisfied, the process moves to the next sector (step 9a), and it is determined whether all the sectors in the test zone have been used (step 9b). If not, the process of step 9d is performed. The process proceeds to step 9c, and if all are used, the process ends with an error in step 9c.
Then, when the determination condition of step 95 is satisfied, the series of test read / write sequences ends.

In the test reading other than immediately after the insertion of the disc, the flow shifts to the flowchart after the end of the flowchart. The flowchart of FIG. 9 is illustrated.
Since the test reading pattern is recorded immediately after the disk is inserted, the sector where the pattern is recorded is
U, and after confirming the read power at Band 0, the read power is similarly confirmed at Band 16 (step 101).
The read power of each band is obtained (step 10).
2) The processing can be terminated.

The above sequence is summarized as follows.

That is, a repetitive pattern of long marks / spaces is recorded on a test track of a medium such as GIGAMO, and a signal is reproduced by changing the reproducing power without applying a reproducing magnetic field. In this state, unlike normal MSR reproduction as shown in FIG. 13, an aperture is not formed and a signal cannot be reproduced until direct transfer to a reproduction layer is performed as shown in FIG. 14). As shown in FIG. 15, the reproduction power when the signal is reproduced is stored as the direct transfer start power _Pr2 , and thereafter the reproduction power is reduced to a power sufficiently smaller than the MSR reproduction, and the external magnetic field is reduced. Apply. At this time, as shown in FIG. 16, if the external magnetic field is normally applied, the GIGAMO medium forms a mask over the entire spot, and the signal cannot be read. Further, the reproducing power is varied while an external magnetic field is applied, and the reproducing start power at that time is stored as _Pr1 . In the GIGAMO medium, the direct transfer power _Pr2 is sufficiently higher than _Pr1 (see FIG. 10), and since conditions for causing direct transfer are specified in advance, the reproduction power for performing MSR reproduction can be selected. Also, since the reproduction of the recording pattern at the time of direct transfer is confirmed, it can be confirmed that the information is always recorded regardless of the recording power at the time of the test reading. In addition, lower the playback power,
When an external magnetic field is applied, the magnetic field strength is varied until the reproduced signal disappears, a correction coefficient including a magnetic field strength decrease amount due to temperature fluctuation or the like is added to the magnetic field strength, and the calculated magnetic field strength is set, thereby setting the drive. It is possible to set the strength of the MSR reproducing magnetic field while minimizing the burden on the MSR.

[0048]

As described above, by using the optical disk apparatus of the present invention, it is possible to guarantee that a recording signal exists in an area where an appropriate reproducing power is required in a medium such as GIGAMO. And the subsequent recording power can be accurately obtained. In addition, when the reproducing magnetic field is applied and the reproducing magnetic field is M
It is possible to confirm whether the strength is sufficient for performing the SR reproduction.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic diagram of an optical disk device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a flowchart for branching whether or not erasure to a test track is to be performed depending on the state of a disk when performing a test read in the optical disk device according to the embodiment of the present invention.

FIG. 3 is an optical disc device according to an embodiment of the present invention;
The figure which shows the flowchart which writes a reproduction | regeneration pattern on a test track and detects the transfer reproduction power _Pr1 directly in a test track.

FIG. 4 is an optical disc device according to an embodiment of the present invention;
The figure which shows the flowchart which lowers reproduction | regeneration intensity | strength and changes a reproduction | regeneration magnetic field until a mask is formed.

FIG. 5 is an optical disc device according to an embodiment of the present invention;
It performed MSR reproduction, a flowchart showing the process for detecting a reproduction start power _{P r1} and the optimum reproducing power _{P r.}

FIG. 6 is an optical disc device according to an embodiment of the present invention;
The figure which shows the flowchart which detects the writing start sensitivity.

FIG. 7 is an optical disk device according to an embodiment of the present invention;
FIG. 4 is a diagram illustrating a flowchart for calculating recording power based on write start sensitivity.

FIG. 8 is an optical disk device according to an embodiment of the present invention;
FIG. 9 is a view showing a flowchart of verification of a test reading and test writing sequence.

FIG. 9 is an optical disc device according to an embodiment of the present invention;
The figure which shows the processing flowchart of only trial reading.

FIG. 10 is a view showing the C / N characteristics of the GIGAMO medium when the reproducing power is changed with or without the application of the reproducing magnetic field in the optical disc device according to the embodiment of the present invention.

FIG. 11 is a diagram showing a track layout of a GIGAMO disk in the optical disk device according to the embodiment of the present invention.

FIG. 12 is a diagram showing a data RF signal in the optical disc device according to the embodiment of the present invention.

FIG. 13 is a view showing the orientation of each magnetic domain of the intermediate layer of the D-RAD medium and the reproduction layer perpendicular magnetization film when the reproduction magnetic field and the reproduction intensity are changed in the optical disk device according to the embodiment of the present invention.

FIG. 14 is a diagram showing the orientation of each magnetic domain of the intermediate layer of the D-RAD medium and the reproduction layer perpendicular magnetization film when the reproduction magnetic field and the reproduction intensity are changed in the optical disc device according to the embodiment of the present invention.

FIG. 15 is a view showing the orientation of each magnetic domain of the intermediate layer of the D-RAD medium and the reproduction layer perpendicular magnetization film when the reproduction magnetic field and the reproduction intensity are changed in the optical disc device according to the embodiment of the present invention.

FIG. 16 is a diagram showing the orientation of each magnetic domain of the intermediate layer of the D-RAD medium and the reproducing layer perpendicular magnetization film when the reproducing magnetic field and the reproducing intensity are changed in the optical disc device according to the embodiment of the present invention.

FIG. 17 is a diagram illustrating a change in a reproduction signal due to a change in a reproduction magnetic field when the reproduction intensity is high and when the reproduction intensity is low in the optical disc device according to the embodiment of the present invention.

FIG. 18 is a diagram showing an aperture formation state in a D-RAD method according to a conventional embodiment.

[Explanation of symbols]

P r _... playback power, _{P r z} ... regeneration upper limit _{power, P rn} ...
Reproduction power when no reproduction magnetic field is applied, _Pr1 ... MSR
Lower limit power for detecting a reproduction signal, _Pr2 ... lower limit power for MSR reproduction, 3 ... PWM, 11 ... optical disc device,
12 optical disk, 14 bias generator, 15 optical head, 16 objective optical system, 17 mirror, 18 beam splitter, 19 LD

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 7/005 G11B 7/005 A

Claims (4)

[Claims] 1. An optical disc apparatus for reproducing by irradiating a recording medium with a laser beam, wherein a repetitive pattern of long marks / spaces is recorded on the recording medium, and the recording layer is formed on the reproducing layer without applying an external magnetic field. When changing the data of
The reproducible lower limit power is set to _Pr2, and thereafter, an external magnetic field is applied to return the direct transfer of the reproducing layer to perform super-resolution reproduction.
The lower limit power for detecting a reproduction signal as _{P r1,} reproducing power _{P r,} multiplied by a constant gamma to _{P r1, P r = γ ×} P r1 (γ ≧ 1) or, internally dividing point P of the _{P r1} and _{P r2 r} = a · P _{r1 + b ·} P _r2 (where a <1, b <1
And an arithmetic operation of a + b = 1) and setting a reproduction power such that _{Pr1 ≦ Pr < Pr2} . 2. After the recording medium is inserted, the data written on a test track is used to set the reproduction power for the first time of the reproduction power, and the second and subsequent reproduction powers after the recording medium is inserted. The optical disk device according to claim 1, wherein the setting is performed. 3. The pattern according to claim 1, wherein a pattern for repetition of a long mark / space is used as a pattern used for obtaining reproduction power by direct transfer to a reproduction layer when no external magnetic field is applied. Optical disk device. 4. A step of recording a repetitive pattern of long marks / spaces on the recording medium and varying the reproducing power to a level at which data in the recording layer is directly transferred to the reproducing layer without applying an external magnetic field. 2. The optical disk apparatus according to claim 1, wherein in the step of lowering and applying an external magnetic field and returning the direct transfer of the reproducing layer, a magnetic field intensity required for MSR reproduction is confirmed or calculated.