JP3770064B2 - optical disk - Google Patents

Description

【００２４】
【表２】

【００２５】
この結果から明らかなように、比較例１は緩衝領域が２０μｍと狭いため、ディスクの偏芯及びバーコード作製機の偏芯が重なった部分で記録トラックに影響を及ぼしてしまう。また、比較例２は記録トラックに影響が及ぶ限界であり、影響が及ばないものも出るが完全になくすことは困難である。また、比較例３の場合も、緩衝領域が４０μｍと狭いため、ＮＧ数は２９枚にも達している。
これに対して、実施例１〜６は、緩衝領域の幅は全て５０μｍ以上であってＮＧ数は無しである。従って、溝を有しない緩衝領域８、１０を半径方向に５０μｍ以上の幅とすることで、記録トラックへの影響を防止することが可能となることが判明した。
【００２６】
【発明の効果】
以下に、本発明の光ディスクによれば、次のように優れた作用効果を発揮することができる。
本発明によれば、バーコードの形成時にバーコードがバーコード領域よりもはみ出しても、その内外周側に緩衝領域を設けてあるので、バーコードが記録領域に侵入して形成されることを防止できる。従って、記録トラックに悪影響を与えることを防止できる。
【図面の簡単な説明】
【図１】本発明に係る光ディスクを示す平面図である。
【図２】図１中のＡ部を示す拡大模式図である。
【図３】記録用単盤の拡大大面図である。
【符号の説明】
４…記録領域、６…バーコード領域、８，１０…緩衝領域、１２…バーコード、１２Ａ…バー部分、Ｄ…光ディスク。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disc with a unique barcode, and more particularly to a recording / reproducing optical disc that can improve instability of reading due to eccentricity of the barcode forming device and the disc itself.
[0002]
[Prior art]
In general, an optical disk may be given a unique identification number for the purpose of preventing unauthorized copying of recorded information or the appearance of pirated copies. Various methods for assigning a unique number to an optical disc have been proposed. Among them, a method of forming a barcode on the disc itself and using this as a unique number is used in CD-ROMs and DVD-ROMs. For example, in the method represented by Japanese Patent Laid-Open No. 10-233019, a barcode is formed by melting and removing the reflective film using a pulse laser such as a YAG laser with high processing accuracy.
[0003]
[Problems to be solved by the invention]
By the way, this method using the YAG laser is effective in the case of a ROM medium in which the reflection film of the optical disk is made of Al alone. However, since the recording disk medium has a film other than the reflection film, In addition to the case where the same barcode cannot be formed, there is a disadvantage that the YAG laser device is expensive.
Furthermore, even when a bar code is manufactured using a YAG laser with high processing accuracy, there are cases where the bar code is straddling due to the eccentricity of the disk itself or the eccentricity of the spindle that rotates the disk.
[0004]
This track crossing is caused by the fact that the recorded bar code protrudes from the original bar code area due to the eccentricity of the disk or the spindle, and the boundary part of the bar code area cannot be separated in units of tracks. To do. The portion where such a track straddle has occurred cannot be recorded / reproduced partially because the bar code portion is applied to the track that should be in a state where it can be completely used for one rotation.
In the case of a recording type optical disc, it is not preferable that a part of the recording area becomes unusable for recording due to the formation of the barcode as described above. An object of the present invention is to provide an optical disc capable of preventing a bar code from being attached in a state of entering a recording area.
[0005]
[Means for Solving the Problems]
As a result of studying a method for eliminating the influence of eccentricity, the inventors of the present invention have found that the cause of straddling of the track is the eccentricity of the disk itself and the eccentricity of the spindle used when forming the barcode, and the barcode area. The present invention has been achieved by finding that the formation of the buffer area on the inner and outer peripheral sides of the disk prevents the track straddling due to eccentricity from entering the recording area.
[0006]
The present invention according to claim 1 is an optical disc having a bar code area formed along a track direction inside a wide ring-shaped recording area, on the inner side of the bar code area and the bar code area. The optical disk is characterized in that a buffer area is provided between a certain recording area and between the barcode area and a recording area on the outer periphery side of the barcode area.
[0007]
In this case, as defined in claim 2, for example, the buffer region may be set to have a width of 50 μm or more in the radial direction.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an optical disk according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a plan view showing an optical disk according to the present invention, FIG. 2 is an enlarged schematic view showing part A in FIG. 1, and FIG.
As shown in FIG. 1, this optical disk D is a rewritable recording / reproducing type disk. A central hole 2 is formed in the center of the optical disk D, and a wide ring-shaped recording area 4 is provided around the center hole 2. . In the recording area 4, a large number of ring-shaped or spiral tracks (not shown) are formed.
[0009]
In the illustrated example, a bar area 6 having a substantially semicircular arc shape is formed by being divided into a part of the recording area 4, and as shown in FIG. The buffer regions 8 and 10 having a predetermined width, which are the features described above, are formed. In the example shown in the figure, each region is described as a straight line instead of an arc. Further, the entire circumference is secured as an area where the barcode can be formed. The buffer areas 8, 10 are areas where nothing is used for recording normal information. The bar code area 6 is provided for the purpose of forming a bar code 12 represented as an aggregate of bar portions 12A, in which the unique numbers of the optical disc D are appropriately separated. In some cases, the bar portion 12A penetrates into the recording area 4 due to the buffer areas 8 and 10 due to the eccentricity of the disk itself and the eccentricity of the spindle. It can prevent being formed in a state.
[0010]
That is, by providing buffer areas 8 and 10, an area that is not used for recording is formed on the inner and outer peripheral sides of the barcode area 6, and the eccentric component is placed within the area, whereby the barcode is applied to the recording area 4. Is to prevent.
As described above, the buffer areas 8 and 10 are areas that cannot be used for recording, and can be formed by providing areas without grooves, or even if grooves are formed, no physical address is assigned. Or by providing a physical address for which writing is prohibited. Most preferably, the buffer areas 8 and 10 are not designated as writable addresses while ensuring the continuity of the grooves and addresses from the front and back.
[0011]
The width L1 of the buffer regions 8 and 10 is determined by the amount of eccentricity of the disk or spindle. As a result of examining the amount of eccentricity of the disk, the mechanical accuracy of the spindle, etc. The upper limit is not limited from the aspect of straddling the track, but in consideration of the utilization efficiency of the disk, it is preferable to keep it to 200 μm or less in practice. If the width L1 of the buffer regions 8 and 10 exceeds 200 μm in the radial direction, it will adversely affect the utilization efficiency such as disk capacity reduction, which is not preferable.
In addition, when the width L1 of the buffer areas 8, 10 is less than 50 μm, the track straddling portion affects the recording track, and therefore the portion that cannot be recorded on the recording track on the inner or outer peripheral side of the buffer areas 8, 10 This is not preferable. Here, the width L2 of the barcode area 6 is about 2 mm.
[0012]
In addition, as a result of examining whether it is possible to form a barcode by using the difference in reflectance between the crystallized part and the amorphous part, which is a characteristic of optical recording media, as a method of forming a bar code, When the rate was 18% or more and the reflectance of the amorphous portion was 4% or less, the barcode signal could be read stably. In this case, the bar portion 12A is an amorphous portion.
The reflectance of the crystallized portion is preferably 18% to 30%. This is because if the reflectivity of the crystallized portion is lower than 18%, the reflectivity of the target recording / reproducing optical desk is not reached, so that the barcode reading becomes unstable.
[0013]
The reflectance of the amorphous part is preferably as low as 4% or less. This is because if the reflectance of the amorphous portion exceeds 4%, the threshold value of the low reflection portion will be exceeded when it is read as a barcode signal, and it will not be established as a signal, making it impossible to read the barcode.
Here, since the Example and comparative example of this invention were actually produced and evaluated, the evaluation result is demonstrated.
[0014]
<Example 1>
The bar code area 6 has a disk radius of 22.00 mm to 24.00 mm, and the buffer area is adjacent to the area 6 with a disk radius of 21.95 mm to 22.00 mm and a disk radius of 24.00 mm to 24.05 mm. 8, 10 were formed. Accordingly, the width L2 of the barcode area 6 is 2.00 mm, and the width L1 of each buffer area 8, 10 is 0.05 mm. The buffer regions 8 and 10 here are formed by a method that does not provide a groove, and the portion where the groove is not formed is in a mirror state.
[0015]
Except for the above areas, a 0.6 mm thick substrate formed by using a stamper formed with a groove having a groove width of 0.4 μm and a groove depth of 40 nm at a pitch of 0.75 μm as in a normal optical disk is used for recording. Necessary films were sequentially formed by sputtering to form a single disk for recording as shown in FIG.
As the composition of the film, four components of AgInSbTe were used as the composition of the recording layer 24, and a film having a thickness of 20 nm was formed using a target having a ratio of 10/10/50/30 (atm%).
Dielectric films 22 and 26 were formed on the upper and lower sides of the recording layer 24 by forming ZnS-SiO ₂ as a dielectric with a thickness of 80 nm on the lower side (substrate 20 side) and 20 nm on the upper side, respectively. Further, as the reflective film 28, Al—Ti (Ti is 3 atm% with respect to Al 97 atm%) was formed to a thickness of 200 nm.
After this film formation, a UV (ultraviolet) curable resin was applied as a protective film 30 with a thickness of 5 μm, and this was cured to obtain a single recording board. This single disk for recording was bonded to a thickness of 1.2 mm using a 0.6 mm thick dummy substrate and an adhesive sheet to obtain a target disk. The eccentricity of the optical disk thus produced was 12 μm.
[0016]
Next, an initialization device modified so that the barcode area and other areas could be initialized continuously was used to continuously initialize the recording portion and produce the barcode.
This time, except for the part where the barcode is formed, crystallization is performed using a normal initialization device, but it is of course possible to perform initialization and barcode production continuously using the same initialization device. is there. The eccentric component obtained by adding up the eccentricity and the feed pitch unevenness of the barcode manufacturing machine used is 14 μm.
In this way, 100 optical discs were prepared, and bar code reproduction was evaluated in order to evaluate the influence on the recording track. Bar code reproduction was evaluated at the center of the bar code recording range, and the output of the pickup head when only the focus servo was performed was used to evaluate the reflectivity of the bar code portion. Also, the effect on the recording track is when the track closest to the buffer area is used, the reflectance fluctuation is confirmed and recorded / reproduced in the still state, and there is a reflectance fluctuation due to the barcode production part, or recording is not possible Was NG.
[0017]
A disk evaluation apparatus manufactured by Pulse Tech was used for evaluation of disk characteristics and barcode. At this time, the reflectance of the crystallized portion of the barcode portion was 21%, and the reflectance of the non-crystallized portion was 3.5%. The reflectivity adjustment of the samples in the following examples is performed by adjusting the film thickness of the dielectric constituting the recording film, and the film thickness configuration is optimized so as to obtain the respective target reflectivities.
[0018]
<Example 2>
Example 1 except that the region adjacent to the barcode region 6 where no groove is formed, that is, the buffer regions 8 and 10 have a disk radius of 21.80 mm to 22.00 mm and a disk radius of 24.00 mm to 24.20 mm, respectively. It produced similarly and evaluated similarly.
[0019]
<Example 3>
The initialization power was 80% when the initialization power of Example 1 was 100%, and the reflectance of the crystallized portion was 18%. The reflectance of the amorphous portion was formed above and below the recording layer 24. The thickness of the dielectric film 22 on the lower side (substrate 20 side) of the dielectric films 26 and 22 is set to 75 nm with respect to 80 nm of the first embodiment, and the reflectance is set to 3%. Produced.
[0020]
<Example 4>
It was fabricated in the same manner as in Example 3 except that the thickness of the lower dielectric film 22 was 85 nm and the reflectance of the amorphous portion was 4%.
<Example 5>
Example 1 except that the region adjacent to the barcode region 6 where no groove is formed, that is, the buffer regions 8 and 10 are set to a disc radius of 21.93 mm to 22.00 mm and a disc radius of 24.00 mm to 24.07 mm, respectively. It produced similarly.
<Example 6>
From the innermost circumference of the disk, a management area such as PCA (Power Calibration Area) is provided as a groove area to which an address is assigned, a buffer area 8 having a width of 50 microns is provided on the outer side, and a barcode area 6 is provided on the outer circumference side. The buffer area 10 having a width of 50 microns is provided outside the area, and the data recording area is provided outside the buffer area 10. Grooves and addresses including the bar code area 6 and the buffer areas 8 and 10 are continuously given from the inner periphery of the disk. Assuming that the innermost start address is A, the inner end management area end address is B, and the data recording area 4 start address is C, the writable addresses are A to B and C to the outer end address. The area between ˜C is not designated as a writable address, and a bar code area 6 is provided between B and C by providing a radius of 50 microns on the outer periphery from B and 50 μm on the inner periphery from C. Further, the width of 50 microns before and after the barcode is made to function as the buffer regions 8 and 10.
The addresses in the buffer regions 8 and 10 are formed as land prepits, and the land prepits and grooves in the buffer regions are also formed when the substrate is formed.
[0021]
<Comparative Example 1>
The area adjacent to the bar code area 6 where no groove is formed, that is, the buffer areas 8 and 10 are in the range of the disk radius of 21.98 mm to 22.00 mm and the disk radius of 24.00 mm to 24.02 mm, respectively. It produced similarly.
<Comparative Example 2>
Example 1 except that the region adjacent to the barcode region 6 where no groove is formed, that is, the buffer regions 8 and 10 have a disk radius of 21.96 mm to 22.00 mm and a disk radius of 24.00 mm to 24.04 mm, respectively. It produced similarly.
<Comparative Example 3>
In Example 6 above, the buffer regions 8 and 10 were each set to 40 μm in width, B to C were designated as writable addresses, and the others were produced in the same manner as Example 6.
[0022]
Tables 1 and 2 below show the results of confirming the effect on the reading of bar codes and recording tracks using these optical discs.
Bar code reproduction was evaluated at the center of the bar code recording range, and the output of the pickup head when only the focus servo was performed was used to evaluate the reflectivity of the bar code portion. Also, the effect on the recording track is when the track closest to the buffer area is used, the reflectance fluctuation is confirmed and recorded / reproduced in the still state, and there is a reflectance fluctuation due to the barcode production part, or recording is not possible Was NG.
[0023]
[Table 1]

[0024]
[Table 2]

[0025]
As is clear from this result, in Comparative Example 1, since the buffer area is as narrow as 20 μm, the recording track is affected at the portion where the eccentricity of the disk and the eccentricity of the barcode manufacturing machine overlap. Further, Comparative Example 2 is a limit that affects the recording track, and there are some that do not affect the recording track, but it is difficult to eliminate them completely. In the case of Comparative Example 3, the buffer area is as narrow as 40 μm, so the number of NGs reaches 29.
On the other hand, in Examples 1 to 6, the widths of the buffer regions are all 50 μm or more and there are no NG numbers. Therefore, it has been found that the influence on the recording track can be prevented by setting the buffer regions 8 and 10 having no groove to have a width of 50 μm or more in the radial direction.
[0026]
【The invention's effect】
In the following, according to the optical disk of the present invention, the following excellent effects can be exhibited.
According to the present invention, even if the bar code protrudes beyond the bar code area when the bar code is formed, the buffer area is provided on the inner and outer peripheral sides thereof, so that the bar code is formed by entering the recording area. Can be prevented. Therefore, it is possible to prevent the recording track from being adversely affected.
[Brief description of the drawings]
FIG. 1 is a plan view showing an optical disc according to the present invention.
FIG. 2 is an enlarged schematic view showing a part A in FIG. 1;
FIG. 3 is an enlarged large view of a single recording board.
[Explanation of symbols]
4 ... recording area, 6 ... barcode area, 8,10 ... buffer area, 12 ... barcode, 12A ... bar part, D ... optical disc.

Claims (1)

In an optical disc having a barcode area formed along the track direction inside a wide ring-shaped recording area,
Buffer areas are provided between the barcode area and the recording area on the inner circumference side of the barcode area, and between the barcode area and the recording area on the outer circumference side of the barcode area, respectively . An optical disc characterized by

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