JP2000260069A - Draw type optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a direct read after write(DRAW) type optical disk of a hybrid type which is capable of improving the C/N of wobbling of a program memory area and improving the stability at the time of DRAW without increasing the jitters of an information area. SOLUTION: This DRAW type optical disk is a stamper for manufacturing, by molding the DRAW type optical disk 31 of the hybrid type having wobbled pregrooves 2 and prepits 4a and 4a. The wobble quantity of the program memory area E3 formed by the prepits 4a is specified to >=90 nm and the wobble quantity of the prepits 4b of the information area E5 is made smaller than 900 nm, by which the stability at the time of DRAW is improved without increasing the jitters of the information area E5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a so-called CD-R
The present invention relates to a write-once optical disc referred to as (Compact Disc Recodable).

[0002]

2. Description of the Related Art Generally, a standard for a recordable optical disc called a CD-R is defined by a standard book called an orange book. Here, in a normal CD-R, as shown in FIG. E1 indicates a pre-groove area. This pre-groove 2 is meandering (wobbling), and the fluctuation of the wobbling cycle causes
Time information called ATIP (Abusolute Time In Pre-groove) is recorded. The CD-R is a PCA (Power Calibr) for setting the light amount in order from the inner peripheral side.
area) E2, a Program Memory Area (PMA) area E3 for recording position information at the time of additional recording, a Lead-In Area (LIA) area E4 for recording table of contents (Table of Contents), and data recording. PA (Program Area = information area) area E
The information is recorded by recording pits along the pregroove 2 with a CD writer.
After recording the information, the CD-R records the recorded position information (A
(TIP time) can be added by recording in the PMA area E3. Therefore, in the CD-R after the additional recording, the pits 3 are formed in a part of the PA area E5 and a part of the PMA area E3 as shown in FIG.

As shown in FIG. 4, some CD-Rs have pre-pits 4 pre-recorded on some of them.
In general, a hybrid CD-ROM
It is called R. In this case, a part of the PA area E5 and P
The pre-pits 4 are formed in a part of the MA area E3. Such pre-pits 4 also meander (wobble) similarly to the pre-groove 2.

A method of manufacturing such a CD-R type optical disk 1 will be described with reference to FIG. This optical disk 1 is roughly formed by a resist forming step (FIG. 5A),
Exposure step (FIG. 5 (b)), development step (FIG. 5 (c)), electroforming step (FIG. 5 (d)), glass peeling step (FIG. 5 (e)), resist removal / stamping step (FIG. 5 (f)), the molding step (FIG. 5)
(g)), a recording agent application step (FIG. 5 (h)), and a reflection / protection layer forming step (FIG. 5 (i)).

[0005] First, a photoresist film 12 is formed on a disk-shaped glass plate 11, and the glass plate 11 is irradiated with a laser beam 13 while being rotated by an exposure device, so that a spiral latent is formed on the photoresist film 12. An image 14 is formed. When this is developed, the photoresist film 12 at the portion of the latent image 14 is formed.
Are dissolved to form pits 15 and grooves 16. Next, a stamper 17 is formed by forming a conductive film on the surface and performing electroforming. Therefore, the stamper 17 is used as a mold to duplicate the molded plate 18 in large quantities.
The optical disk 1 is manufactured by applying a recording agent 19 such as a dye to the molded plate 18 and sequentially forming the reflective layer 20 and the protective layer 21.

In such a manufacturing method, in the case of the hybrid type, in the resist forming step, the photoresist film 12 is sandwiched by the photoresist film 1 with the intermediate layer 22 interposed therebetween.
2a and 12b are formed in two layers. In the exposure step, the laser light 13a having a large light amount and the laser light 13b having a small light amount are provided.
By using the exposure light amount properly by using
5 and shallow grooves 16 are separately formed. Thereby, the pit 15 having a large depth from the upper surface of the upper photoresist film 12b to the lower surface of the lower photoresist film 12a and the depth from the upper surface of the upper photoresist film 12b to the upper surface of the lower photoresist film 12a are formed. A stamper 17 having a shallow groove 16 is manufactured. This is molded, and a recording agent 19 is applied to the entire surface in the same manner as in the case of a normal CD-R,
The reflective layer 20 and the protective layer 21 are sequentially formed, and the hybrid type CD-R type optical disc 1 in which information is recorded in advance by pre-pits on a part thereof is manufactured. In terms of area, e1 is an inner mirror surface area, e2 is an information area, e3 is an outer mirror surface area, and the information area e2 is further divided into a ROM area e21 and a recording area e22.

With respect to such a hybrid type CD-R, according to JP-A-9-7232, the amount of wobble between prepits and pregrooves is defined so as to satisfy the Orange Book standard. .

[0008]

However, as shown in FIG. 6, the WCN (ratio between the carrier amplitude of the wobble and the noise amplitude) in the pre-pit portion gradually increases as the amount of the wobble increases. As shown in (1), if the amount of wobble is excessively increased, the jitter becomes worse. In addition,
FIGS. 6 and 7 show examples of measured values of media prepared by applying a phthalocyanine dye to a substrate having a pit depth of 290 nm and a pit width of 0.7 μm.

Here, the WCN is specified to be 26 dB or more according to the Orange Book. However, the WCN of a medium recorded by a writer is generally 30 dB or more, and the WCN is 32 dB for additional writing by a general writer without any problem.
It is desirable that this is the case. In particular, in the case of a hybrid CD-R disc in which pre-pits are formed only in a part of the PMA, it is difficult to set the PMA part to the same signal level as the information area. I do. This is because when there is only one prepit in the pregroove, prepit distortion or the like is likely to occur during molding. However, the writer additionally writes the PMA while reading the pre-groove ATIP information during the PMA recording, but the additional information is written in the information recorded in the pit by the same time information (subcode information) as the ATIP information in the pit. Therefore, the ATIP information of the pre-groove or pre-pit can be additionally written by the subcode information even if the ATIP information cannot be read accurately. On the other hand, according to the Orange Book specification, the jitter is specified to be 35 ns or less.

As shown in FIGS. 6 and 7, WCN ≧ 32
In order to achieve dB and jitter ≦ 35 ns, the satisfying range is only a narrow range in the vicinity of a wobble amount of 100 nm, and it is difficult to stably produce a large amount due to variations in the prepit shape.

It is an object of the present invention to provide a hybrid write-once optical disc capable of improving the wobbling C / N of a program memory area and improving the stability at the time of additional write without increasing jitter of an information area. Aim.

[0012]

According to the first aspect of the present invention,
A hybrid write-once optical disc having a wobbled pre-groove and a pre-pit, wherein a wobble C of a program memory area formed by the pre-pit is formed.
/ N is higher than the C / N of the wobble of the pit in the information area.

Therefore, in order to perform additional recording, it is desirable that the C / N of the wobble of the program memory area formed of pre-pits is higher than the C / N of the pit of the information area. It is possible to improve the stability at the time of additional writing without increasing the jitter of the information area in which the lower the jitter of the written information is, the better.

According to a second aspect of the present invention, there is provided a hybrid write-once optical disc having a wobbled pre-groove and a pre-pit, wherein the wobble amount of the program memory area formed by the pre-pit is larger than the wobble amount of the pit of the information area. large.

Therefore, by making the wobble amount of the program memory area formed by the pre-pits larger than the wobble amount of the pits of the information area, it is possible to improve the stability at the time of additional writing without increasing the jitter of the information area.

According to a third aspect of the present invention, in the write-once optical disc according to the second aspect, the wobble amount of the program memory area formed by pre-pits is 90 nm or more, and the wobble amount of the pits of the information area is 90 nm.
Less than.

Accordingly, the wobble amount of the program memory area formed by the pre-pits is set to 90 nm or more, and the wobble amount of the pits of the information area is set to less than 90 nm.
The jitter of the information area can be reduced to 2 ns or more and 35 ns or less.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. The same portions as those shown in FIGS. 2 to 7 are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, a hybrid type CD-R optical disk (write-once optical disk) 3 having a pre-pit 4 as shown in FIG.
The present invention relates to a structure of a stamper, which is a mold for molding No. 1.
In this stamper, in this embodiment, the WCN of the pre-pit 4a in the PMA area E3 is set to 32 dB or more higher than the Orange Book specification, and the PA area E5
The WCN for the inner pre-pit 4b is set to 26 to 30 dB. Thereby, basically, it is possible to suppress the jitter in the PA area E5, in which the higher the WCN in the PMA area E3, the higher the WCN in which it is desirable to perform additional recording, and the lower the jitter in the additionally recorded information, the more desirable.

For example, as a specific first embodiment, a master is manufactured by the method described above with reference to FIG. 5, and the wobble amount of the prepit 4a in the PMA region E3 is 110 nm, and the wobble amount of the prepit 4b in the PA region E5. Was set to 80 nm. In both the PMA region E3 and the PA region E5, a stamper having pre-pits 4a and 4b having a depth of 290 nm and a pit width of 0.7 μm was formed, molded with this stamper, and coated with a phthalocyanine dye to obtain a hybrid CD-ROM. R optical disk is manufactured, and the occurrence state of the malfunction when the write operation is performed 20 times each using different CD writers A and B,
When the jitter in the PA region E5 was evaluated, the results shown in Table 1 were obtained.

The second embodiment shown in Table 1 corresponds to the PMA region E3
The wobble amount of the pre-pit inside is 100 nm, and the PA area E
5 is an example in which the pre-pit wobble amount is 60 nm. Comparative Example 1 is an example in which the pre-pit wobble amount in the PMA area E3 and the pre-pit wobble amount in the PA area E5 are both 50 nm. Comparative Example 2 is the PMA area E3.
Example in which both the wobble amount of the pre-pit in the middle and the wobble amount of the pre-pit in the PA area E5 were 80 nm, Comparative Example 3
Indicates that the wobble amount of the prepit in the PMA region E3 and the wobble amount of the prepit in the PA region E5 are both 110 nm.
Here is an example. Other conditions are the same as those in the first embodiment.

[0021]

[Table 1]

According to the results shown in Table 1, the wobble amount of the pre-pit in the PMA area E3, PA
In Comparative Examples 1, 2, and 3 in which the amount of pre-pit wobbles in the area E5 was the same, it was difficult to achieve both the jitter of the PA area E5 and the high WCN in any case. The wobble amount of the pre-pits 4a in the PMA area E3 is set to 90 nm or more as shown in FIGS.
By setting the wobble amount of the middle pre-pit 4b to less than 90 nm and varying the wobble amount, the WCN in the PMA region E3 is 32 dB or more, and the jitter in the PA region E5 is 35%.
It can be seen that it is possible to achieve both at the same time. Thereby, the stability at the time of additional writing can be improved without increasing the jitter in the PA area E5.

[0023]

According to the first aspect of the present invention, the C / N of the wobble in the program memory area formed by the pre-pits is preferably high in the C / N of the high wobble for additional recording.
Is higher than the C / N of the wobbles of the pits in the information area. Therefore, it is desirable that the jitter of the additionally written information is lower, thereby improving the stability at the time of additional writing without increasing the jitter of the information area.

According to the second aspect of the present invention, the wobble amount of the program memory area formed by the pre-pits is made larger than the wobble amount of the pits of the information area. Can be improved.

According to the third aspect of the present invention, in the write-once optical disc according to the second aspect, the wobble amount of the program memory area formed by the pre-pits is set to 90 nm or more, and the wobble amount of the pits of the information area is made smaller than 90 nm. Therefore, the wobble C / N in the program memory area is 32 dB or more, and the jitter in the information area is 35 n
s or less.

[Brief description of the drawings]

FIG. 1 is a CD-ROM for describing an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing an R-type optical disc.

FIG. 2 is a schematic cross-sectional structure diagram showing a region configuration of a general CD-R type optical disc.

FIG. 3 is a schematic sectional view showing a CD-R type optical disc for explaining the additional recording state.

FIG. 4 is a schematic sectional view showing a hybrid type CD-R type optical disc.

FIG. 5 is a process diagram showing an optical disk manufacturing process.

FIG. 6 is a characteristic diagram showing a relationship between a wobble amount and a WCN.

FIG. 7 is a characteristic diagram showing a relationship between a wobble amount and jitter.

[Explanation of symbols]

 2 Pregroove 4a, 4b Prepit E3 Program memory area E5 Information area

Claims (3)

[Claims] 1. A hybrid write-once optical disc having wobbled pre-grooves and pre-pits, wherein a C / N of a wobble in a program memory area formed by the pre-pits is larger than a C / N of a wobble of a pit in an information area. High write-once optical disc. 2. A write-once optical disc of a hybrid type having wobbled pre-grooves and pre-pits, wherein a wobble amount of a program memory area formed by pre-pits is larger than a wobble amount of pits of an information area. 3. The write-once optical disc according to claim 2, wherein the wobble amount of the program memory area formed by pre-pits is 90 nm or more, and the wobble amount of the pits of the information area is smaller than 90 nm.