JP2003123335A - Optical disk and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk, which is annealed with an optimal annealing power, and a production method therefor. SOLUTION: The optical disk is provided with a track for test for finding out an optimal power for annealing both the sides of a recording and reproducing track with a light beam and a track for ID for recording and reproducing the identification number of an anneal device. The production method for optical disk is provided with a step for annealing both the sides of the recording and reproducing track with the set power, step for preparing an inspection track, in which the track for test is annealed with a plurality of different powers with the set power as a center, step for deciding the propriety of the annealed recording and reproducing track, step for finding out the optimal anneal power, and step for changing the set power to the optimal anneal power.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc that requires annealing by a light beam and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, AV (audio and
Application to visual) is active. For example, in DVDs (Digital Versatile Discs) mainly for movie contents, write-once and rewritable formats such as DVD-R, DVD-RAM, and DVD-RW have been developed and are becoming popular as VTR next-generation recorders. . With the spread of BS digital broadcasting and broadband communication in the future, a large-capacity optical disc format capable of recording higher quality compressed video and a compact, portable, high-density optical disc format with the same network capacity will appear. Be expected. As an example of realizing such high-density recording, DWDD (Domain Wall Di
An optical disc of the displacement detection (domain wall movement detection) method has been proposed. In the DWDD type optical disc,
It is necessary to weaken magnetic coupling between adjacent recording tracks (reduction of magnetic anisotropy). Therefore, in the case of manufacturing a DWDD type optical disc, initialization (hereinafter referred to as annealing, annealing method or annealing treatment) for weakening magnetic coupling between adjacent recording tracks is performed before recording an information signal. To do.

Japanese Patent Application No. 2001-120689 discloses an optimum setting method of annealing power in the above-mentioned annealing method. In this conventional example, in order to obtain the optimum annealing power, a method for irradiating the power test area provided on the optical disk with a test annealing power and measuring the reflectance thereof to determine the optimum annealing power and the test A method for determining the optimum power by reflectance measurement during irradiation of annealing power for a laser is shown.

[0004]

However, in the above-described method for determining the annealing power, since the change in the reflectance with respect to the annealing power is small depending on the structure of the recording film,
It was found that the determined optimum power varied and the reproducibility was poor in some cases. Therefore, this method cannot be said to be sufficient for the usage in which the annealing power margin is narrowed as a result, especially aiming at higher density, and a more accurate annealing power learning method is required. For that purpose, a test (normally referred to as a recording / playback inspection) is performed to check whether recording / reproduction is possible or not by performing the same recording / reproduction as in actuality, or measuring the jitter or error rate to determine whether annealing is optimal. It is considered best to carry out.

By the way, since the annealing is carried out in the disk manufacturing process, it may be difficult to carry out the normal recording / reproducing inspection at that time. In the example of the DWDD optical disc, it is desirable that the annealing is performed with the light spot being most narrowed. Annealing from the light input surface side (over the substrate) for normal recording / reproduction is not practical because a lens with a high NA cannot be used due to the effects of aberration due to substrate thickness unevenness and tilt. Since the DWDD optical disc has a single-sided specification, if the annealing is performed from the side with the recording film (the film surface), the light spot is not affected by the above-mentioned aberration, so that the short wavelength (blue) light beam can be narrowed down by the high NA lens. . However,
In this case as well, it is desirable to anneal from the film surface before applying the protective coat that affects the aberration. As described above, it is preferable to perform the annealing from the film surface without the protective coating, but if the magnetic head is used without the protective coating, the recording surface will be damaged. It cannot be done in stages. Even if a normal recording / reproduction inspection can be performed using a flying magnetic head or the like, if a protective coat is applied, the recording / reproduction sensitivity will shift slightly, so correction is necessary to calculate the optimum annealing power.

In order to carry out the normal recording / reproducing inspection, it is desirable that the optical disc has a protective coat and the like and is in a completed cartridge. With this configuration, it is economical to use this mass-produced drive device compatible with optical disks. In a mass-produced drive device, the magnetic head and the optical head can be easily positioned at predetermined positions with respect to the optical disc due to the relationship between the loading mechanism and the cartridge.

On the other hand, consider the possibility of annealing in the cartridge. First, it is necessary to overcome the aberration problem of the protective coat and enable annealing through the protective coat. Then, it is necessary to make the annealing optical head enter the cartridge opening from the magnetic head side so that the entire area of the optical disk can be accessed. To do so, the annealing optical head for manufacturing equipment that uses a blue laser should be stored in a size that is equal to or smaller than the optical head optimized for mass production.
It is necessary to develop a new mechanism dedicated to annealing including loading. Even with the development requiring such a large investment, it is practically difficult to dispose the magnetic head and the annealing optical head on the same side in the opening of the cartridge. That is, since the annealing and the normal recording / playback inspection cannot be performed by the same device, it is considered that there is no merit to anneal the optical disk contained in the cartridge.

As described above, at present, there is a problem that the annealing process and the inspection process for accurately determining the optimum annealing power cannot be performed in one place, and there is no effective means for determining the optimum annealing power. It was In order to solve this problem, the present invention finds an optimum annealing power and provides an optical disk annealed with the optimum annealing power and a manufacturing method thereof.

[0009]

In order to achieve the above object, the optical disk of the present invention is an optical disk in which both sides of a recording / reproducing track for recording / reproducing data are annealed with a light beam of a predetermined power. A plurality of test tracks for finding the optimum annealing power, and an identification number (ID) of the annealing device for performing the annealing.
Is provided with an ID track for recording and reproducing.

According to the optical disk of the present invention, before and after annealing the recording / reproducing track of the annealing device, it is inspected in the downstream inspection step whether the annealing power is appropriate or how much it is shifted from the appropriate value. You can create a test track for. At the same time, the annealing device I
Since D can be recorded on the ID track, the annealing device can be specified in the downstream inspection process even if annealing is performed by a plurality of annealing devices, and if the annealing power is shifted, the target annealing device is sure to be used. The annealing power of can be corrected to an appropriate value (optimal annealing power).

Further, in the optical disc of the present invention, each bit recording of the ID of the ID track is performed with the predetermined annealing power or higher annealing power.
It is a recording method of recording whether or not a plurality of sections having a predetermined length or more are annealed or not, and in reproducing the ID, data of a predetermined pattern is recorded in advance on the entire ID track,
After the recording, it is preferable that the reproducing method is to reproduce each bit of the ID by discriminating the presence / absence or the large / small of the data for each section on the ID track and determining whether or not there is annealing. According to this preferred example,
The ID can be recorded by using the annealing function of the annealing device, and the reproduction of the ID can be realized only by mounting a simple function of detecting the presence / absence of a signal in normal recording / reproduction and incorporating it in the microcomputer.

In the optical disc of the present invention, number information based on a predetermined rule is recorded on the ID track in addition to the ID, and the ID and / or the number information is recorded / reproduced on the pre-recording / re-recording track. It is preferably used as a media ID for data management. According to this preferable example, the media ID information that can be used for copyright protection or the like can be embedded in the target optical disc without introducing a new separate process.

Further, in order to achieve the above object, the optical disk manufacturing method of the present invention is an optical disk in which both sides of a recording / reproducing track for recording / reproducing data are annealed with a light beam of a predetermined power, and is optimal for the annealing. Of a plurality of test tracks for finding various powers and an ID track for recording / reproducing the identification number (ID) of the annealing device for performing the annealing, which is a pre-recording / re-recording track. A first step of annealing both sides of the test track with a set power corresponding to the predetermined power, and a second step of creating an annealing inspection track in which the test track is annealed with a plurality of different powers centered on the set power. An annealing step of annealing the optical disk using the annealing device including A third step of writing / verifying a part or all of the recording / reproducing track to determine the quality of the pre-recording / reproducing track, and writing / verifying the annealing inspection track to find the optimum annealing power of the annealing apparatus. It is characterized by including an inspection step of determining the quality of the optical disk by using an optical disk inspection apparatus including the step 4 and an annealing power adjustment step of changing the set power to the optimum annealing power found in the inspection step.

According to the optical disc manufacturing method of the present invention, it is possible to accurately determine whether the annealing power is appropriate by actually recording / reproducing the test track created in the annealing process in the optical disc inspection process, and to determine the annealing power of the annealing device. If is shifted, it can be readjusted to the optimum annealing power, so that an optical disk annealed with the optimum annealing power can always be obtained.

Further, in the optical disc manufacturing method of the present invention, the annealing step comprises a plurality of annealing devices to which IDs are assigned, and each annealing device has a fifth step of recording the respective IDs on the ID tracks. Including,
The optical disc inspection device in the inspection step includes a sixth step of reading an ID from the ID track, and the annealing device 1 specified by the ID from the plurality of annealing devices.
It is preferable to change the set power to the optimum annealing power for each table. According to this preferable example, even when the annealing process is composed of a plurality of annealing devices, the annealing device can be specified and readjusted to the optimum annealing power without fail.

Further, in the optical disc manufacturing method of the present invention, each bit recording of the ID of the ID track in the fifth step has a predetermined annealing power or a higher annealing power and has a plurality of predetermined lengths or more. Is recorded by annealing or not annealing, and the ID is reproduced by recording data of a predetermined pattern on the entire ID track in advance, and after recording, for each of the sections on the ID track. It is preferable that the reproduction method is to reproduce the respective bits of the ID by determining the presence / absence of the data and the presence / absence of annealing depending on the presence / absence of the data. According to this preferred example, according to this preferred example, the ID can be recorded by using the annealing function of the annealing device, and the reproduction of the ID can be easily performed by a microcomputer for detecting the presence / absence of a signal in normal recording / reproduction. It can be realized only by implementing various functions.

In the optical disc manufacturing method of the present invention, it is preferable that, in the fifth step, number information based on a predetermined rule is recorded as the media ID on the ID track in addition to the ID. According to this preferable example, a media ID that can be used for copyright protection and the like
Information can be embedded in the target optical disc without introducing a new separate process.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall view of the optical disc 100 of the embodiment and a diagram showing the uses of each track. In FIG. 1, an optical disk 100 is a sample servo type magneto-optical disk, 101 is a plurality of tracks, and is a data area (recording / reproducing track) for actually recording and reproducing data such as user data and management information. It is necessary to include the test area for the drive, and all the recording / reproducing tracks 101 in this area should be annealed so that recording / reproducing can be performed. Each track has multiple segments 10
It consists of two. The number of the segments 102 per track is, for example, 1280, which is a sufficient number for the tracking servo. The segment 102 is a pit area 103 for recording a sample servo signal and an address signal.
And a groove area 104 for recording and reproducing data. On the inner and outer circumferences of the optical disc,
A lead-in area 105 and a lead-out area 106 are arranged. Except for the groove area of the control track 105a, which will be described later, the segment 102 is formed in the same manner as the data area 101.

The track configuration of each area is shown on the right side of FIG. That is, the lead-in area 105 is composed of a control track 105a in which information about how to use the disk is previously recorded, and a plurality of tracks for testing the annealing power (corresponding to power learning of normal data) in order from the inner circumference. Track 105b and an ID track 105c for recording ID information such as an annealing device ID. In the groove area 104 in the segment 102 of the control track 105a, a part of the groove is composed of prepits (also called emboss). The lead-out area 106 is I
D track 106a and test track 106
b. ID tracks 105c and 106a
Any one of them works well.

FIG. 2 is a diagram showing the structure of the optical disc 100 in the DWDD reproduction system, and is a perspective view (2a) showing a partial cross section of the data area 101 and an enlarged view (2b) of the cross section. In FIG. 2 (2 a), 201 is the optical disc 100.
The substrate is formed by injection molding of polycarbonate and has a thickness of, for example, 0.4 mm to 1.2.
It is about mm. The track pitch is set as small as 0.7 μm or less for higher density. 202 and 203
Are a groove and a land that form the groove area 104, respectively. Reference numerals 204, 205, 206, and 213 are a first wobble pit, a second wobble pit, an address pit, and a mirror portion that form the pit area 103, respectively. 207 is a first dielectric layer, 208 is a magnetic layer,
209 is a second dielectric layer which is formed on the substrate in this order to form the laminated thin film 200 as a whole. The first dielectric layer 207 and the second dielectric layer 209 include, for example, Si ₃ N ₄ and Al.
Transparent dielectric materials such as N, SiO ₂ , SiO, ZnS, MgF ₂ and composites thereof can be used.

Reference numeral 210 denotes a magnetic coupling interruption area, which is for separating tracks of the optical disk 100 and for preventing adverse effects from adjacent tracks during DWDD reproduction.
To form the magnetic coupling blocking area 210, the optical disc 100 is formed.
In the manufacturing process of, the annealing device described later is used. A high-power annealing light beam (light spot) 212 obtained by narrowing a laser beam with an objective lens 211 which is a part of the annealing device is applied to the land 203 and the laminated thin film 200 on the extension line thereof to obtain magnetic characteristics. Is formed by deteriorating. In the actual disc manufacturing, the optical disc 1
For each sheet, it is necessary to anneal both sides of the track for normal recording and reproduction, including the data area 101.
Specifically, by scanning the land in the area to be annealed with a predetermined annealing power while tracking,
Annealing can be realized. In this case, in order to reduce the manufacturing cost, it is required that the scanning speed be as fast as possible and the scanning be realized in a short time.

The width of the magnetic coupling interruption region 210 is preferably as small as possible in order to narrow the track pitch and increase the density. One of the reasons why it is necessary to reduce the size is to increase the energy density of the annealing light beam 212 locally.
The laminated thin film 200 can be deteriorated, and the scanning speed, that is, the linear velocity can be increased with the same power.
Another reason is that a push-pull signal is detected from a land of a track having a smaller track pitch to perform tracking. In order to make the diameter of the annealing light beam 212 as small as possible, here, for example, Ga is used.
A short laser light source with a wavelength λ of about 400 nm, such as an N semiconductor laser element or an SHG element that halves the wavelength of a red laser, is used, and the NA of the objective lens is 0.6 or more than usual.
By setting the ratio to 5 to 0.85, the annealing light beam determined by λ / NA is narrowed down.

When an objective lens having a short wavelength or a high NA is used, the laminated thin film 2 is passed through the substrate 201 (a laser beam is made incident from the lower side of the figure) as in normal recording and reproduction.
If a light beam is to be formed on the optical axis 00, the aperture performance of the light beam is significantly deteriorated with respect to the tilt of the substrate as compared with a normal light beam, and this is not a preferable method. Paradoxically, in order to form a stable light beam through the substrate, it is difficult to shorten the wavelength of the laser light source and increase the NA of the objective lens.

Therefore, here, in the annealing treatment, laser light is made incident from the laminated thin film 200 side. By doing so, the influence of the substrate tilt can be removed, so that the laminated thin film 2 can be formed by shortening the wavelength of the laser light source and increasing the NA of the objective lens.
A small and excellent light beam for annealing can be formed on 00. For example, the size of the annealing light beam 212 with λ = 405 nm and NA = 0.85 is about 0.44 times smaller than the size of the light beam with wavelength λ = 650 nm and NA = 0.6 used for normal recording and reproduction. it can.

When the disc is viewed from the surface of the laminated thin film 200, the land 203 is seen in the foreground, so that it looks like a groove for normal reproduction, so attention must be paid to the tracking polarity. Also, in this type of optical disk, a protective coat of about several μm is usually applied by spin coating after film formation, but if this protective coat is provided, the S-shape of the focus interferes and the precision of focusing on the film surface becomes weak. However, since there are problems such as the aberration of the objective lens occurring due to the uneven thickness of the protective coat and the influence of the tilt due to the thickness of the protective coat cannot be ignored, annealing is preferably performed without the protective coat. However, uneven coating due to dust during protective coating,
To avoid defects, the annealing process needs to be performed in a clean environment.

The land 203 is arranged mainly for realizing annealing in addition to the effect of thermal separation between the tracks. In addition, for normal recording and reproduction, the land 2
Separately from 03, a first wobble pit 204 and a second wobble pit 205 are provided. Apply sample servo so that each wobble signal has the same magnitude,
The reproducing light beam can scan the center of the groove 202. The wobble pits are arranged so that even if the recording / reproducing beam has twice the diameter of the annealing light beam 212, the pits are alternately arranged on the odd-numbered and even-numbered tracks.

Next, the structure of the magnetic layer 208 will be described. Figure 2
In (2b), reference numerals 21, 22, and 23 are a domain wall motion layer, a blocking layer, and a recording layer, which are formed in this order on the first dielectric layer 207 to form a magnetic layer 208.

The thickness of the second dielectric layer 209 is determined by irradiating laser light for annealing from the second dielectric layer 209 side.
The reflectance is low, and the light is set to be efficiently absorbed. Specifically, the thickness of the second dielectric layer 209 is λ
It is preferably around λ / (12 × n) or more and λ / (2 × n) or less (preferably λ / (6 × n) or more and λ / (2 × n) or less). .

The magnetic layer 208 includes three or more magnetic layers so that reproduction can be performed by the DWDD system. Magnetic layer 208
Is a layer annealed by using the light of wavelength λ incident from the second dielectric layer 209 side. As an example of the magnetic layer 208, when the magnetic layer 208 includes the domain wall motion layer 21, the blocking layer 22, and the recording layer 23 which are sequentially stacked from the substrate 201 side, the following materials are used for each layer. it can. The material of the domain wall displacement layer 21 is a material having a small domain wall coercive force and a small saturation magnetization in the temperature range near the Curie temperature of the blocking layer 22, and the Curie temperature of which is the recording layer 2.
A material lower than 3 and higher than the barrier layer 22 can be used. For example, GdCo, GdFeCo, or an alloy thereof having a Curie temperature of about 220 ° C. to 260 ° C. can be used.

The material of the blocking layer 22 has a Curie temperature lower than that of the domain wall displacement layer 21 and the recording layer 23.
It is preferable to use a material having a large domain wall coercive force just below the Curie temperature. For example, DyFe and TbF
e, or an alloy thereof, can be used, and one having a typical Curie temperature of 140 ° C. to 180 ° C. can be used.

The recording layer 23 has a large domain wall coercive force, has a higher Curie temperature than the domain wall displacement layer 21 and the blocking layer 22, and uses a material having a small saturation magnetization in a temperature range near the Curie temperature of the blocking layer 22. be able to. For example, TbF
eCo or its alloy, Curie temperature 280 ℃ ~
Those at 300 ° C. can be used.

FIG. 3 shows the optical disc 100 described above.
FIG. 3 is a diagram for explaining the manufacturing process (3a) and the manufacturing procedure (3b) of FIG. In the following description, for convenience of explanation, it is assumed that 106b of 105b and 106b is used for the test track and 106a of 105c and 106a is used for the ID track, but the actual usage is the opposite. Or both may be used to improve reliability.

In the manufacturing step (3a), first, in the molding / film forming step of S301, the optical disk substrate is molded by injection molding, and the magnetic layer 208 and the like are formed on the substrate by sputtering. Then, it is annealed (S30
2: Annealing process). Annealed optical disc 100
Is coated with a protective coat and a lubricant, a clamping plate for a magnet clamp is welded, and then stored in a cartridge (S303: protective coat / assembly process). The optical disc 100 stored in the cartridge is
In the optical disk inspection step S304, in addition to the test relating to the quality of annealing, a recording / reproduction test and a process corresponding to shipping inspection and setting such as physical, logical, and application formats for a non-defective optical disk are performed. The optical disc 100, which is a non-defective product and is completed here, is shipped to the market through the packaging / shipping process S305.

Since the annealing process S302 and the optical disc inspection process S304 take a lot of time per sheet as compared with the other processes, a plurality of annealing devices and a plurality of optical disc inspection devices are respectively provided to adjust the process time. Place and use. The arrows in FIG. 3 indicate this. As will be described later, in the optical disc inspection step S304, since the difference between the set annealing power and the optimum annealing power for each annealing apparatus can be measured, the annealing power of each annealing apparatus is optimally corrected based on the difference (S306: annealing power adjustment). ).

Since there is a possibility that a defect may occur if the annealing power is corrected for each optical disk due to variations in sensitivity of the optical disk 100, mixing of defects, etc., statistical processing such as averaging is performed and the feedback is periodically provided to the annealing apparatus. Is preferred. However, when the annealing is incomplete and the recording / reproducing becomes defective, the target annealing apparatus is immediately stopped, and the apparatus is replaced / repaired. It is preferable to introduce computer-based automation because the above operation is inefficient and may cause errors if it is performed manually.

Specific examples of the annealing device and the optical disc inspection device will be described later with reference to FIGS. 6 and 7, respectively.
Each operation procedure (step) is as shown in (3b1) and (3b2) of FIG.

That is, in the operation procedure of the annealing device of (3b1), first, the normal recording / reproducing groove 202 is started in a state of being tracked by the reproducing power, the address is read, and the seek is performed to the track at least one before the data area 101. , The land 203 is half-jumped so as to change the tracking polarity to cancel the still jump, the power is increased to the annealing setting power, the lands 203 arranged in the spiral are continuously scanned, and the whole recording / reproducing track 101
Both sides of are annealed (S307). When the annealing is finished, the power is once returned to the reproduction power and the groove 20
Track to 2 and set the standby state where the address can be read.

Next, the test track 106b is sought to serve as a test track for the annealing power, and the test track 106b annealed with different annealing powers around the set power is created (S308). The test track 106b has, for example, a set power of 5 mW and 3.5 mW to 6.5 mW in 13 steps of 0.25 mW.
Create five street 106b each. The test track 106b can be created by performing an operation of cutting off the annealing operation with five powers for each power, or by performing an operation of sequentially increasing the annealing power during the annealing operation.

After returning to the standby state once, the ID track 106a is finally sought to record the ID (S3).
09). The tracking polarity at this time is basically the groove 202. The recording power of the ID is set to the set annealing power or higher, and surely deteriorates the section of the target groove. For simplification, the ID track 106a is used without changing the tracking polarity during annealing.
Both ends of the groove may be annealed with high power to deteriorate the characteristics of the groove, but this is not a preferable method because the adjacent tracks are also deteriorated at the same time.

Next, the operation procedure of the optical disc inspection apparatus of (3b2) will be described. The optical disc 100 to be inspected is already in the cartridge. The optical disc inspection device has
It is economically appropriate to use a mass-production normal drive device with normal recording / playback. Only the operations related to the quality judgment of annealing are shown here, and the description of the contents related to the above-described formatting operation and other shipping inspections is omitted.

The optical disc inspection apparatus starts the optical disc,
For example, 1 in 16 recording / playback tracks 101 that have been annealed
Write / verify (W / V) is performed at the ratio of books to determine whether the tracks are good or bad (S310). If a defect of a predetermined level occurs at this stage, the optical disk to be inspected is determined to be defective. However, in order to determine whether this defect is due to annealing, the subsequent steps are performed even if it is defective.

Next, the test track 106b for each set value of the annealing power created by the annealing device is W / V, the upper and lower annealing powers at which W / V becomes NG are found, and the average power is optimized. It is calculated as power (S311). In this optimum power calculation step, normal GO / NO is used to detect more accurate power.
The optimum anneal power can be found more accurately by performing jitter measurement and error rate measurement instead of GO / V of GO, and by changing the reproduction parameter sensitive to annealing power variation and performing reproduction characteristic inspection. To be When the difference between the upper limit power and the lower limit power found here falls below a predetermined value, the result is NG. Also, the test track 106b
When a defect is found in the above, it is processed so as to be excluded from the optimum power calculation.

Finally, the ID track 106a is sought, the ID information is read (details will be described later), the annealing device for the optical disc 100 that has just been inspected is specified, and this is used for the annealing power adjustment S306.

If a track jump or the like occurs during the annealing and the annealing is interrupted, an attempt is made to retry the annealing from the point of interruption, and if a track jump still occurs, the track jump is skipped and the annealing is performed. To do. However, it is necessary to limit the length of the skipped track to a level that does not affect subsequent normal recording / playback. Also, during the annealing, the land 203 and the pit area 103
Pit quality etc. is checked and the upstream molding / film forming process S
Feedback to 301 is also effective. Of course, it is also important not to create a defective optical disc by detecting a failure or defect in the annealing device itself.

FIG. 4 is a diagram for explaining a specific method of the above-mentioned ID recording and reproduction. First, record the device ID (4
Shown in a). The ID track 106a is recorded.
Is allocated to a section divided into a predetermined length or more, and bits of ID information are assigned. Here, for simplicity, segment 10
One of 2 is set as one section. The ID information is recorded by irradiating a "power equal to or higher than a preset annealing power" and a "reproduction power level" for each segment 102 according to "1" and "0" of the bit.

The magnetic properties of the portion irradiated with the set annealing power or more are deteriorated similarly to the annealing. The degree of this deterioration is detected by the following reproduction processing. (4b) is
The pattern recording before reproduction is shown. ID track 106a
Then, the laser intensity is set to the recording level, the magnetic head is magnetically modulated, and recording is equivalently performed on the ID track 106a. The data pattern here is a signal of a single frequency. There is little problem in mounting because a low frequency that can be recorded for each segment and that is capable of normal MO reproduction rather than a high frequency that requires super-resolution reproduction is sufficient. Next, the ID track 106a prepared here is reproduced (4c).
With or without deterioration of the magnetic characteristics of the segment 102, the reproduction amplitude of the MO becomes small / large respectively, which can be detected as an envelope and reproduced as bits "1" / "0".

In the above embodiment, one segment is assigned to one bit, but one track has, for example, 128 bits.
Since there are as many as 0 segments, 128 bits of ID information may be inserted or 8 segments or more may be allocated per bit. Further, when 1 bit is assigned to a plurality of segments, it is also preferable to devise such as DC-free modulation so that the number of segments annealed for each 1 bit is constant in order to improve the reproduction reliability.

FIG. 5 shows an example of ID information recorded on the ID track 106a. 16 bits are sufficient for the ID of the annealing device, but the ID information is recorded in a nonvolatile manner for each optical disc 100. It is considered effective to extend and use as a media ID used for distribution. Another advantage is that no new process is required for that purpose.

(5a) is an example of simple ID information.
401 is a device ID, and 402 is its error detection code C.
It is RC. Here, double writing is performed in order to improve read reliability.

(5b) and (5c) are the optical disc 100
This is an example of ID information in which an ID is given for each sheet and the manufacturing history is also known. 403, 404, 405
Are the manufacturer ID, the date of manufacture, and the serial number of the optical disc 100, respectively. The serial number 405 may be a serial number initialized every manufacturing date. Grant I
D406 is a number given by the copyright management mechanism or the like. Reference numerals 407 and 408 are an error detection code CRC and an error correction code ECC for the above collection of information 413, respectively. In this example, it is assumed that the information set 413 is used as a media ID.

(5c) is a set of information 413, the assigned ID
In this example, the set 414 of information excluding 406 and the assigned ID 406 are divided. 409 and 410 are the former CRC and EC
C, 411 and 412 are the latter CRC and ECC. This makes it possible to use the information set 414 and the assigned ID as different media IDs. Note that I
In addition to the media ID, the D information can also be used for process control by recording the inspection result data of the pit signal quality of the optical disk, which is considered to be suitable to be performed simultaneously by the annealing device, and the error occurrence point during annealing. Is.

FIG. 6 is a block diagram of the main part of the annealing apparatus used in the annealing process of this embodiment. In FIG. 6, 501 is a GaN semi-aperture laser with λ = 405 nm,
502 is an irradiation power detector that measures a part of the emitted light of the semiconductor laser 501 as irradiation power, 503 is a beam splitter, and 211 is an objective lens with NA 0.75.
The laser light emitted from the semiconductor laser 501 passes through the beam splitter 503 and the objective lens 211 and is focused on the land 203 of the optical disc 100 to form an annealing light beam 212. The emission power of the semiconductor laser 501 is controlled by the anneal power control unit 506 based on the detection result of the irradiation power detector 502 by the normal power servo method.

The annealing light beam 212 is absorbed by the laminated thin film 200 of the optical disc 100 and converted into heat, and is reflected and returned to the annealing optical head 500 as reflected light. Objective lens 211 and beam splitter 5
A λ / 4 plate (not shown) is arranged between the light sources 03 and 03, the optical path of the reflected light is changed by the beam splitter 503, and the reflected light is guided to the reflected power detector 505. The output of the reflected power detector 505 is used for focus error signal detection, tracking error signal detection, track address reading, and the like. 507 is an optimum annealing power setting unit, which is a DIP switch or EEPR
The set power value is set as a code in the OM or the like, and a series of processes of the annealing device is executed based on the set power value.

Reference numeral 508 is an ID setting section, which is also a DIP.
The device ID information is stored in a switch or EEPROM, and the ID information is created based on this value and recorded in the ID track 106a. Figure 5 (5b) and (5c)
In the case of extending the ID information as described above, it is preferable to send the information from the host controller using the annealing device as a slave. If CRC and ECC are calculated in advance by an unillustrated microcomputer for controlling the annealing device, the increase in the amount of hardware can be small.

FIG. 7 is a block diagram of the main part of the optical disc inspection apparatus used in the optical disc inspection process of this embodiment. In FIG. 7, 601 is a semi-transparent laser having a wavelength λ = 650, 602 is an emission (irradiation) power detector that measures a part of the emission light of the semiconductor laser 601 as irradiation power, and 6
Reference numeral 03 is a beam splitter, and 604 is an objective lens with NA of 0.6. The laser light emitted from the semiconductor laser 601 passes through the beam splitter 603 and the objective lens 604 and is focused on the groove 202 of the optical disc 100 to form a recording / reproducing light beam 610. The emission power of the semiconductor laser 601 is controlled by the recording / reproduction control unit 606 based on the detection result of the emission power detector 602.

The recording / reproducing light beam 610 is linearly polarized in order to detect the MO signal. During recording, the light beam 610 magnetizes the laminated thin film 200 of the optical disc 100 by the magnetic head 609 while recording the information while magnetically modulating the magnetic head 609 as a recording power (constant frequency pulse modulation). Further, the light beam 610 applies reproduction power to the laminated thin film 200 during reproduction, and detects domain wall movement and / or a normal magneto-optical state as a MO signal indicating a change in Kerr rotation angle. The light beam 610 reflected as the MO detection signal is
Returning to the objective lens 604, the beam splitter 603
It is guided to the MO signal detector 605. MO signal detector
In addition to the focus error signal and tracking error signal, M
The O differential signal and the addition signal for sample servo / address reading are sent to the recording / reproducing control unit 606. 607 is a recording / reproducing control unit 6
The optimum annealing power storage unit stores the optimum annealing power obtained in step S311 executed in 06. Reference numeral 607 denotes I performed by the recording / reproduction control unit 606.
A reproduction ID storage unit that stores the ID information read in the D reproduction step S312. In addition, CRC of ID information
The hardware and ECC are not necessary to add hardware if they are calculated later by a microcomputer for controlling the optical disk inspection device (not shown).

In the above embodiments of the present invention, the optical disk of the sample servo in the DWDD reproducing system has been described as a specific example. However, the present invention
DW is not limited to the recording material of the optical disc
It can also be applied to the improvement of the characteristics of magneto-optical materials other than DD, and the inter-track annealing for stabilizing the reflectance and recording characteristics by applying a predetermined power between the tracks of the phase change material in advance. Needless to say, the servo system can also be used for continuous servo. Further, it can be effectively used for manufacturing other than the optical disc, such as forming a guide with a light beam on the magnetic disc.

[0058]

As is apparent from the above description, by using the optical disk and the manufacturing method thereof according to the present invention, the annealing power of the annealing device used in the annealing process can be always kept optimum, and the optimum annealing power can always be maintained. An annealed optical disc and its manufacturing apparatus can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of an optical disc according to an embodiment of the present invention.

FIG. 2A is a sectional perspective view of an optical disc according to an embodiment of the present invention. FIG. 2B is an enlarged view of an optical disc according to an embodiment of the present invention.

FIG. 3 is a diagram showing a manufacturing process and a manufacturing procedure in the embodiment of the present invention.

FIG. 4 is an explanatory diagram of an ID recording / reproducing method according to an embodiment of the present invention.

FIG. 5 is a diagram showing a data example of ID information according to the embodiment of the present invention.

FIG. 6 is a block diagram of an annealing device used in an optical disc manufacturing process according to an embodiment of the present invention.

FIG. 7 is a block diagram of an optical disc inspection apparatus used in an optical disc manufacturing process according to an embodiment of the present invention.

[Explanation of symbols]

100 optical disks 101 data area (recording / playback track) 102 segments 103 pit area 104 groove area 105 Lead-in area 105a control track 105b Annealing power test track 105c ID truck 106 Lead-out area 106a ID truck 106b Annealing power test track 200 laminated thin film 201 substrate 202 groove 203 land 204 First Wobble Pit 205 Second Wobble Pit 206 address pit 207 First dielectric layer 208 magnetic layer 21 Domain wall moving layer 22 Barrier layer 23 recording layer 209 Second dielectric layer 210 Magnetic coupling blocking area 211 Objective lens (for annealing) 212 Light beam for annealing 213 Mirror section S301 Molding / film forming process S302 Annealing process S303 Protective coat and assembly process S304 Disc inspection process S305 Packing / shipping process S306 Annealing power adjustment 401 Device ID 402, 407, 409, 411 CRC 403 Manufacturer ID 404 Date of manufacture 405 serial number 406 Assigned ID 408,410,412 ECC 500 Optical head for annealing 501 semiconductor laser 502 Irradiation power detector 503 beam splitter 505 Reflection power detector 506 Annealing power controller 507 Optimal annealing power setting section 508 ID information setting section 600 Recording / playback optical head 601 Semiconductor laser 602 Output power detector 603 beam splitter 604 Objective lens 605 MO signal detector 606 Annealing power controller 607 Optimal annealing power storage 608 Playback ID storage unit 609 Magnetic head 610 Recording / reproducing optical beam

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahiro Oberagawa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Takashi Inoue             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5D075 EE03 FF11 GG16                 5D090 AA01 BB04 BB10 CC01 DD03                       GG01 GG16

Claims (7)

[Claims] 1. An optical disc in which both sides of a recording / reproducing track for recording / reproducing data are annealed with a light beam having a predetermined power, and a plurality of test tracks for finding an optimum power of the annealing, and An optical disk comprising an ID track for recording and reproducing an identification number (ID) of an annealing device for performing annealing. 2. A recording method for recording each bit of an ID of the ID track by recording with a predetermined annealing power or a higher annealing power depending on whether a plurality of sections having a predetermined length or more are annealed or not. In the reproduction of the ID, a predetermined pattern of data is recorded in advance on the entire ID track, and after the recording, the presence / absence or the large / small of the data for each section on the ID track is not annealed / 2. A reproducing method for reproducing each bit of the ID by discriminating the presence portion.
The described optical disc. 3. A medium ID for data management, wherein number information based on a predetermined rule is recorded in addition to the ID on the ID track, and the ID and / or the number information is recorded / reproduced in a previous recording / reproducing track. The optical disc according to claim 1 or 2, wherein the optical disc is used as. 4. An optical disc in which both sides of a recording / reproducing track for recording / reproducing data are annealed with a light beam of a predetermined power, and a plurality of test tracks for finding an optimum power for the annealing, and the annealing. A method of manufacturing an optical disc having an ID track for recording / reproducing an identification number (ID) of an annealing device for carrying out the method, comprising annealing both sides of a pre-recording / re-recording track at a set power corresponding to the predetermined power. Annealing step of annealing the optical disk by using the annealing apparatus including the step 1 and the second step of forming an annealing inspection track by annealing the test track with a plurality of different powers centering on the set power. And write / verify some or all of the annealed recording / playback tracks. The quality of the optical disk is checked by using an optical disk inspection apparatus including a third step of determining the quality of the recording / reproducing track and a fourth step of finding the optimum annealing power of the annealing apparatus by writing / verifying the annealing inspection track. An optical disk manufacturing method, comprising: an inspecting step for judging; and an annealing power adjusting step for changing the set power to the optimum annealing power found in the inspecting step. 5. The optical disc inspection apparatus of the inspecting step, wherein the annealing step comprises a plurality of annealing apparatuses having IDs, each annealing apparatus including a fifth step of recording the respective IDs on the ID track. Is the ID
A sixth step of reading an ID from the track for use, wherein the annealing power adjusting step changes the set power to an optimum annealing power for each of the annealing devices specified by the ID from the plurality of annealing devices. 5. The method for manufacturing an optical disc according to claim 4, wherein. 6. The bit recording of each ID of the ID track in the fifth step is performed with or without annealing at a predetermined annealing power or a higher annealing power for a plurality of sections having a predetermined length or more. This is a recording method of recording, and in the reproduction of the ID, data of a predetermined pattern is recorded in advance on the entire ID track, and after the recording, the presence / absence of data for each section on the ID track is recorded.
6. The method of manufacturing an optical disk according to claim 5, wherein the reproducing method is for reproducing each bit of the ID by discriminating the non-annealed / non-annealed portions depending on the absence or large / small. 7. The optical disk according to claim 5, wherein in the fifth step, number information based on a predetermined rule in addition to the ID is recorded as the media ID in the ID track. Manufacturing method.