JPH10105972A - Optical recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the test time and to enhance the test efficiency when an optimum recording condition is obtained by performing test recording on an optical recording medium having plural test sectors in the circumferential direction. SOLUTION: One operation of a test recording operation, a confirming operation of test recorded information, an erasing operation and an erasing confirming operation is executed respectively on the all test sectors TS1-TS4 provided on the optical recording medium (optical disk 1) in the circumferential direction during a period of one revolution of the medium. As a result, the test time is drastically reduced and the test efficiency is enhanced as compared with the case of obtaining the optimum recording condition by performing the test recording operation, the confirming operation of test recorded information, the erasing operation and the erasing confirming operation on each sector respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical recording method for performing test recording on an optical recording medium such as an optical disk.

[0002]

2. Description of the Related Art In recent years, an optical recording and reproducing method for recording and reproducing information by accessing a recording medium such as a high-density and large-capacity optical disk at a high speed, a recording apparatus, a reproducing apparatus, and a recording medium used therein. Efforts have been made to develop. By the way, among a wide range of optical recording / reproducing methods, the magneto-optical recording / reproducing method has a unique advantage that it is possible to repeatedly erase information after recording the information and record new information again. And has the greatest attraction.

[0003] A magneto-optical recording disk (recording medium) used in this magneto-optical recording / reproducing system has a layer for recording.
It has a magnetic film consisting of one or more layers. The magnetic film has a high recording density and a high signal strength.
endical magnetic layer
or layers) have been developed and used.

Such a magnetic film is made of, for example, amorphous GdFe (an alloy of gadolinium and iron), GdCo (an alloy of gadolinium and cobalt), GdFeCo (an alloy of gadolinium and iron and cobalt), and TbFe (an alloy of television and iron). , TbCo (an alloy of terium and cobalt), TbFeCo (an alloy of terium and iron and cobalt), and the like. The perpendicular magnetic film generally has a concentric or spiral track on which information is recorded.

[0005] By the way, information is formed as a mark on a track. In the formation of a mark, a characteristic of a laser, that is, a coherence excellent in space and time, is used.
advantage is used to narrow the beam to a spot almost as small as the diffraction limit determined by the wavelength of the laser light. The converged light is applied to the track surface and heats the recording film to form a mark of 1 μm or less on the recording film, thereby recording information. In optical recording, a recording density of up to about 10 ⁸ marks / cm ² can be theoretically achieved. This is because the laser beam can aggregate to a spot having a diameter as small as almost the wavelength.

In magneto-optical recording, a laser beam is focused on a perpendicular magnetic film and heated. Meanwhile, a recording magnetic field Hb is applied from the outside to the heated portion in a direction opposite to the initialized direction. Then, the coercive force Hc (coercity) of the locally heated portion decreases and becomes smaller than the recording magnetic field Hb. As a result, the magnetization of that portion is aligned in the direction of the recording magnetic field Hb. In this way, a reversed magnetized mark is formed.

Next, reproduction of the mark thus formed will be described. Typically, light is an electromagnetic wave having electromagnetic field vectors diverging in all directions on a plane perpendicular to the optical path. Here, when the light is converted into linearly polarized light and radiated to the perpendicular magnetization film, the light is reflected on the surface thereof or passes through the perpendicular magnetization film. At this time, the polarization plane rotates according to the direction of the magnetization. This rotating phenomenon is caused by the magnetic car (ker
r) The effect is called the magnetic Faraday effect.

For example, if the plane of polarization of the reflected light is rotated by θ k degrees with respect to the magnetization in the initialization direction, it is rotated by −θ k degrees with respect to the magnetization in the recording direction. Therefore, if the axis of the optical analyzer (polarizer) is set perpendicular to the plane inclined by θk degrees, the light reflected from the mark magnetized in the initialization direction cannot pass through the analyzer. On the other hand, the light reflected from the mark magnetized in the recording direction is
The sentence multiplied by (sin2θk) × 2 passes through the analyzer and is captured by the detector (photoelectric conversion means).

As a result, the mark magnetized in the recording direction looks brighter than the mark magnetized in the initialization direction, and generates a strong electric signal in the detector. Therefore,
Since the electric signal from the detector is modulated according to the recorded information, the information is reproduced.

Further, as another example of the magneto-optical recording method, there is a light modulation overwrite method (direct overwrite method) as disclosed in JP-A-62-175948. This method basically includes a memory layer (hereinafter, M layer) composed of a magnetic thin film capable of perpendicular magnetization and a recording layer (hereinafter, W layer) composed of a magnetic thin film capable of perpendicular magnetization,
Both layers are exchange-coupled, and using a multi-layer overwritable magneto-optical recording medium capable of keeping only the magnetization of the W layer in a predetermined direction without changing the magnetization direction of the M layer at room temperature. I have. Then, recording is performed on the recording medium with a laser beam pulse-modulated according to the binarized information (that is, a beam pulse-modulated to a high level PH for recording information and a low level PL for erasing information).

On the other hand, there is a recording system called a phase change recording system, and a recording medium used in such a recording system includes:
For example, a medium of GeSbTe (an alloy of germanium, antimony, and terium), which can reversibly repeat a crystalline phase and an amorphous phase, is used. The erasing state is represented by a crystalline state, and the recording state is changed to a non-crystalline state. At the time of reproduction, a light beam is radiated and converted into a strong or weak electric signal by using a difference in reflectance between a crystalline state and an amorphous state. This recording medium can also be overwritten with laser light modulated into two levels, a high level PH and a low level PL.

When recording is actually performed on an optical disk, it is necessary to finely adjust the laser power according to the recording temperature and sensitivity of the disk and the environmental temperature in order to optimize the mark shape. At present, some magneto-optical disk recording devices on the market perform test recording and adjust the sensitivity before recording information.

When test recording is performed, the power is changed between the inner and outer peripheries of the disc or the inner, middle and outer peripheries immediately after the optical disc is mounted on the drive unit or when the temperature of the drive unit changes during use. Erasure, recording, and playback to find the optimum recording power. Optical discs may have sensitivity unevenness in the circumferential direction.Therefore, several test sectors are provided in the circumferential direction to absorb the measurement error due to the sensitivity unevenness, and finally the average is taken to lead to the optimum recording conditions. Will be needed.

FIG. 5 is a flow chart showing the operation in the case where test recording is performed on a recording medium on which recording is performed by the direct overwrite method and the optimum recording power is obtained. This operation example is an example in which the value of the above-mentioned low level PL, that is, the optimum erasing power PL for erasing information is obtained. First, an initial value (a power that is never recorded with this power) is set as the recording power (step S61). Next, a mark is recorded in a test sector of the recording medium (optical disk) with the set power (step S62).

Subsequently, the test sector is reproduced (step S63), and the presence or absence of a recording mark is determined from the reproduced signal (step S64). Here, if the recording mark cannot be confirmed, the value of the recording power is slightly increased (step S65), and the mark is recorded in the test sector with that power (step S62). Then, the test sector is reproduced (step S63). If the recording mark cannot be confirmed from the reproduction signal, the recording power is further increased (step S65), and the mark is re-recorded in the test sector (step S62). The operation of recording a mark in such a test sector is continued until the recording of the mark is actually confirmed, and when it is confirmed that the mark has been recorded, the recording power at that time is stored as PHth (step S6).
6).

Next, after erasing the mark of the test sector,
A mark is recorded in a test sector with a standard recording power (step S67). Subsequently, an initial value (a power that is never erased by this power) is set as an erasing power (step S68). Next, the test sector is erased with the set power (step S6).
9).

Next, the test sector is reproduced (step S70), and it is determined whether or not the mark has been erased from the reproduced signal (step S71). Here, when the recording mark is confirmed without erasing the mark of the sector, the value of the erasing power is slightly increased (step S72), and the test sector is erased with that power (step S69). Then, the test sector is reproduced (step S7).
0) If the recording mark can be confirmed from the reproduction signal, the recording power is further increased (step S72), and the test sector is erased with that power (step S69).

The operation of erasing the mark for the test sector is continued until the erasure of the mark is actually confirmed. When the erasure of the mark is confirmed, the erase power at that time is obtained as PLth (step S73). ,
The erase power PL is calculated from the obtained recording power PHth and erase power PLth (step S74). When the erase power PL is calculated for one test sector in this way,
For the next test sector, the mark recording process and the erasing process are performed in the same manner to obtain the erasing power, and finally the respective averages are taken to determine the optimum recording conditions.

[0019]

Conventionally, such test recording is performed for each test sector to determine the optimum recording conditions. Therefore, it takes too much test time for an optical disk having a plurality of test sectors. However, there is a problem that the test efficiency is reduced. Accordingly, an object of the present invention is to reduce the test time and perform an efficient test when test recording is performed on an optical disk having a plurality of test sectors in the circumferential direction to determine the optimum recording condition.

[0020]

According to the present invention, a test recording operation and a test recording are performed on a plurality of sectors provided in a circumferential direction during one rotation of an optical recording medium. This is a method for executing any one of the information confirmation operation, the erase operation, and the erase confirmation operation. At this time, it is preferable to perform the above operation on all the sectors provided in the circumferential direction (ie, all the sectors provided in one round of the track) during one rotation. Therefore,
The test time is greatly reduced and the test efficiency is improved as compared with a case where the test recording operation, the test recording information confirmation operation, the erasure operation and the erasure confirmation operation are performed for each sector to determine the optimum recording conditions. As the optical recording medium, a recording medium on which information whose light intensity has been modulated into a high level and a low level is overwritten is used.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing a configuration of an optical disk recording apparatus to which the present invention is applied. In the figure, an optical disc recording apparatus is an optical disc 1 as an optical recording medium.
And an optical disc 1 rotated by a rotation mechanism (not shown)
Optical head 2 for recording, reproducing and erasing data with respect to
A seek control circuit 3 for controlling the movement of the optical head 2 to a position of a predetermined sector on a predetermined track of the optical disk 1; and a recording for supplying recording data to the optical head 2 and controlling a recording power and an erasing power of the optical head 2. It comprises a circuit 4, a reproducing circuit 5 for reproducing recorded data from the optical disc 1 outputted via the optical head 2, and a control unit 6 for controlling the above-mentioned units.

The optical disk 1 is a recording medium that can be overwritten by laser light from the optical head 2 that has been modulated into a high level PH and a low level PL, and information is recorded at a high level PH. Information is erased at the level PL. For this reason, before information is recorded, it is necessary to perform test recording to measure optimal recording conditions and record information under the optimal conditions. Further, the optical disc 1 is liable to have sensitivity unevenness in the circumferential direction. For this reason, when performing test recording, several test sectors TS1 to TS4 are provided in the circumferential direction as shown in FIG. 4 in order to absorb a measurement error due to uneven sensitivity. That is, in the present embodiment, as shown in FIG.
A) Four sectors TS1 to TS4 each having a positional relationship of 90 degrees are provided as test sectors.

In FIG. 4, each test sector TS1-T
Of the S4, the sector TS1 has a physically younger sector number, and is sequentially referred to as TS2, TS3, and TS4. Then, the recording power (erasing power) required for data erasing is obtained for each test sector, and the average value of the four test sectors is finally set as the erasing power PL at the radial position.

FIGS. 1 and 2 show a control unit 6 of the present apparatus for performing test recording on the optical disk 1 and finding optimum recording conditions.
6 is a flowchart showing the operation of the first embodiment. The operation of the main part of the present apparatus will be described according to this flowchart. First, an operation for calculating the minimum recording power based on the flowchart of FIG. 1 will be described. First, the control unit 6 has a built-in memory 6
A is set to "0" as the recording confirmation flags WV [1] to WV [4] (step S1). This flag WV
[1] to WV [4] correspond to the sectors TS1 to TS4, respectively, and are set to “1” when it is confirmed that the test data is recorded in the sector. Next, an initial value (a power that is never recorded with this power) is set in the memory 6A as a recording power (step S2).

Subsequently, the seek control circuit 3 is controlled to move the optical head 2 to a position immediately before the test sector TS1 of the rotating optical disk 1 and position it (step S3). Then, it is instantaneously determined whether or not the test data has been recorded in the sector TS1, that is, whether or not the test confirmation flag WV [1] is “1” (step S4). The output power of the recording circuit 4 is controlled so that the optical head 2 can record the test data with the set recording power. As a result, the data recording operation for the sector TS1 of the optical head 2 is performed (Step S5). If the test data has been recorded, the process waits for the time until the head of the next sector TS2 of the optical disk 1 approaches the position of the optical head 2, and then proceeds to step S6.

Subsequent steps S6, S8, S10
In the above, whether the test data has been recorded in each of the sectors TS2 to TS4 is similarly determined by the corresponding recording confirmation flag, and if not, the optical head 2 is similarly set with the test power set in the memory 6A. Controls the output power of the recording circuit 4 so that the test data can be recorded. As a result, the data recording operation for each of the sectors TS2 to TS4 of the optical head 2 is performed in the same manner (step S).
7, S9, S11).

When the operation of recording the test data in each of the sectors TS1 to TS4 is completed, the optical disk 1 makes one revolution and the head position of the sector TS1 approaches the position of the optical head 2. Here, after the positioning of the optical head for detecting the time when the head position of the sector TS1 reaches just before the optical head 2 is performed (step S12), the control unit 6 determines whether the test data has been recorded in the sector TS1. Is instantaneously determined by the recording confirmation flag WV1 (step S1).
3) If not already recorded, the control section 6 inputs the recording data of the sector TS1 read by the optical head 2 as a reproduction signal via the reproduction circuit 5, and stores the level of the reproduction signal in the memory 6A. (Step S14). Also,
If the test data has been recorded, the process waits for the time until the head of the next sector TS2 of the optical disk 1 approaches the position of the optical head 2, and then proceeds to step S15.

Then, the subsequent steps S15 and S1
7 and S19, the respective sectors TS2 to TS
Similarly, whether or not the test data has been recorded in the corresponding sector TS2 to T4 which has been read by the optical head 2 is similarly determined based on the corresponding recording confirmation flag.
The recording data of S4 is input as a reproduction signal via the reproduction circuit 5, and the level of the reproduction signal is stored in the memory 6A (steps S16, S18, S20). Thus, at the first rotation of the optical disk 1, the optical head 2
The result of the recording operation performed on S1 to TS4 is 2
It is read and saved at the rotation.

Next, in step S21, it is determined whether or not the test data has been recorded in each of the sectors TS1 to TS4 by checking the stored reproduction signal level of each of the sectors TS1 to TS4. The recording confirmation flag W corresponding to the sector determined to have been recorded
V is set to "1", and the recording power value at this time is set as the minimum recording power PHth of the corresponding sector.
To memorize. Subsequently, in step S22, each recording confirmation flag is checked to determine whether or not data has been recorded in all test sectors. If there is a test sector in which test data is not recorded, the recording power is increased (step S2).
3) Return the processing to step S3.

In the next steps S3 to S11, test data is recorded in each of the test sectors TS1 to TS4 in the third rotation with the recording power increased, and in the subsequent steps 13 to S20, Data reproduction of each test sector TS1 to TS4 in the fourth rotation is performed. Such test recording is continued until it is confirmed that test data has been recorded in all test sectors. Note that data recording and reproduction are not performed on a test sector for which data has already been confirmed to be recorded. Thus, it is confirmed that the data is recorded in all the test sectors, and if "Y" is determined in the step S22, the processing of FIG. 1 is ended.

The recording power PHth is set to each sector TS1.
After setting corresponding to .about.TS4, the output power of the recording circuit 4 is first determined in step S31 of FIG. 2 so that the optical head 2 can record test data at the reference power in order to obtain the lowest erasing power PLth. And each sector T
Data is recorded in S1 to TS4 with reference power. Next, the erasure confirmation flags RV [1] to RV are stored in the built-in memory 6A.
"0" is set as [4] (step S32).
Each of the flags RV [1] to RV [4] is a sector TS1.
It is set to "1" when it is confirmed that the data of the sector has been erased, corresponding to .about.TS4. Subsequently, an initial value (a power that is never erased with this power) is set in the memory 6A as an erasing power (step S33).

Next, after positioning the optical head 1 immediately before the test sector TS1 (step S34), the sector TS
It is instantaneously determined whether or not 1 has been erased, that is, whether or not the erase confirmation flag RV [1] is "1" (step S3).
5) If the data has not been erased, the output power of the recording circuit 4 is controlled so that the optical head 2 can erase the test data with the erase power set in the memory 6A. As a result,
The data erasing operation for the sector TS1 of the optical head 2 is performed (step S36). If the test data has been erased, the process waits for the time until the head of the next sector TS2 of the optical disk 1 approaches the position of the optical head 2, and then proceeds to step S37.

Subsequent steps S37, S39, S
At 41, whether or not each of the sectors TS2 to TS4 has been erased is similarly determined based on the corresponding erasure confirmation flag. The output power of the test circuit 6 is controlled so that can be erased. As a result, the erasing operation for each of the sectors TS2 to TS4 of the optical head 2 is performed similarly (steps S38, S40, S42).

When the data erasing operation for each of the sectors TS1 to TS4 is completed, the optical disk 1 makes one revolution, and the head position of the sector TS1 approaches the position of the optical head 2. Here, after the positioning of the optical head 2 for detecting the time when the head position of the sector TS1 arrives immediately before the optical head 2 is performed (step S43), the control unit 6 determines whether or not the sector TS1 has been erased. Erase confirmation flag RV1
(Step S44), and if not erased, the control section 6 inputs the information of the sector TS1 read by the optical head 2 as a reproduction signal via the reproduction circuit 5, and The level is stored in the memory 6A (step S45). If the test data has been erased, the process waits for the time until the head of the next sector TS2 of the optical disk 1 approaches the position of the optical head 2, and then proceeds to step S46.

The following steps S46 and S4
8 and S50, each sector TS2-TS
Similarly, it is determined whether or not the sector 4 has been erased by the corresponding erasure confirmation flag. As a reproduced signal, and the level of the reproduced signal is stored in the memory 6A (step S
47, S49, S51). Thus, 1 of the optical disc 1
The result of the erase operation performed by the optical head 2 on each of the sectors TS1 to TS4 at the rotation is read and stored at the second rotation.

Next, in step S52, by checking the stored reproduction signal level of each of the sectors TS1 to TS4, it is determined whether or not the data of each of the sectors TS1 to TS4 has been erased. The corresponding erase confirmation flag RV is set to "1" for the sector determined to have been erased.
Set to. The erase power value at this time is stored in the memory 6A as the minimum erase power PLth of the corresponding sector. Subsequently, in step S53, each erase confirmation flag is checked to determine whether or not data has been erased in all test sectors. If there is a test sector in which test data is not erased, the erase power is increased (step S54). The process returns to S34.

In the next steps S34 to S42, the erasing operation is performed on the test sectors TS1 to TS4 in the third rotation with the erasing power increased, and in the subsequent steps 44 to S51, A reproduction operation is performed on each of the test sectors TS1 to TS4 in the fourth rotation. Such an erasing operation and its reproducing operation (erase confirming operation) are continued until it is confirmed that all the test sectors have been erased. Note that the erasing and reproducing operations are not performed on a test sector for which it has been confirmed that data has already been erased. In this way, it is confirmed that all the test sectors have been erased, and if "Y" is determined in step S53, the average value of the minimum erasing power PLth obtained for each sector and the average value of the minimum recording power PHth described above are obtained. Is substituted into a predetermined formula to calculate the erasing power PL (step S55).

Here, assuming that the number of recordings per sector occurs five times including the initial value when the recording power PHth is simply calculated in FIG. 1, the optical disc 1 makes one rotation at the time of recording and reproduction of all sectors. Therefore, when the optical disk 1 rotates 10 times (2 rotations × 5 times), the recording power PHth
Is required. If the number of erasures per sector occurs four times when the erasing power PLth is obtained in FIG. 2, the optical disk 1 rotates once during erasure and reproduction of all sectors, so that the optical disk 1 rotates eight times (two rotations). × 4 times), the erase power PLth is obtained.

Therefore, in this case, the erasing power PL can be obtained in a total of 18 rotations. On the other hand, when test recording is performed one sector at a time for each rotation of the optical disk 1 to determine the optimum recording condition, 40 rotations (2 rotations × 5 times × 4 sectors) are required to determine the recording power PHth. It takes 32 rotations (2 rotations × 4 times × 4 sectors) to find the erasing power PLth.
Erasing power PL is obtained only after a total of 72 rotations.

As described above, according to the present invention, when test recording is performed on the optical disk 1, the optimum recording conditions can be obtained in a short time by reducing the number of rotations of the optical disk 1, so that the same measurement accuracy as the conventional method is maintained. In addition, the test can be efficiently performed. In this embodiment, an example of calculating the erasing power PL required for erasing information has been described.
Similarly, when a plurality of test sectors are provided in the circumferential direction to determine the recording power PH required for information recording and test recording and reproduction thereof are performed, the same effect can be obtained.

[0041]

As described above, according to the present invention, a test recording operation, a check operation of test-recorded information, and a plurality of sectors provided in a circumferential direction during one rotation of an optical recording medium are performed. Since one of the erasing operation and the erasing confirmation operation is performed, the test recording operation and the
The test time is greatly shortened and the test efficiency is improved as compared with the case where the operation of confirming the test recorded information, the erasing operation, and the erasing confirming operation are performed to determine the optimum recording conditions.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an operation of a main part of the present invention.

FIG. 2 is a flowchart showing an operation of a main part of the present invention.

FIG. 3 is a block diagram illustrating a configuration of an optical disk recording device to which the present invention has been applied.

FIG. 4 is a diagram showing a configuration of an optical disc.

FIG. 5 is a flowchart showing the operation of the conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Optical head, 4 ... Recording circuit, 5 ... Reproduction circuit, 6 ... Control part, 6A ... Memory, TS1-TS4 ...
Test sector.

Claims (2)

[Claims] 1. An optical recording method for performing test recording on a plurality of sectors provided in a circumferential direction of substantially the same radius on an optical recording medium on which information can be recorded, wherein the optical recording medium rotates during one rotation. An optical recording method, wherein one of the test recording operation, the operation of reproducing the test recorded information, the erasing operation, and the erasing confirming operation is performed on a plurality of sectors. 2. The optical recording method according to claim 1, wherein the optical recording medium is overwritten with information whose light intensity has been modulated into at least a high level and a low level.