JP2002260244A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium that can protect illegal copy of recorded information by making reproduction of control data impossible even though control data are recorded in the control data part. SOLUTION: The optical recording medium has groves and land tracks. At least a portion of the groove track has an intermittently divided structure so that forming the groove tracks intermittently can protect illegal copy of recorded data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical recording medium which can be recorded by a user, and to a recording medium which does not allow illegal recording and reproduction of information data, and a method of manufacturing the same.

[0002]

2. Description of the Related Art At present, as an optical recording medium, a recordable DVD-R (Digital Versatile Disc) which can be recorded by a user and has a recording capacity of several gigabytes (Gbytes) is available.
Recordable) and rewritable DVD-RW (D
VD-Rewritable) is being developed. In addition, the remarkable performance improvement of such a large-capacity digital optical recording medium and recording / reproducing apparatus makes it possible to perform high-capacity large-capacity duplication with little deterioration.

FIG. 1 is a diagram showing a layout of physical sectors in a recording surface radial direction, taking a DVD-RW as an example. In an information area for recording information data, a lead-in area, a data area, and a lead-out area are sequentially formed radially outward from a start point of the information area (a start point of a physical sector). As shown in FIG. 2, the lead-in area includes data for reproducing the disc, such as reference codes and control data. The control data area has 192 ECCs (Error Correction Codes).
e) Consists of blocks. In FIG. 2, the configuration of the ECC block in the control data area is 0 to 15
Are shown using the relative sector numbers of These ECC
The contents of each of the blocks are all identical. That is, 192 ECC blocks having the same content are continuously recorded. The ECC block is composed of 16 sectors, and each ECC block records physical format information, disc manufacturing information, and content provider information. Therefore, at the time of recording information data, data related to the reproduction is recorded in the control data area of the lead-in area. At the time of reproduction of the disc, the reproducing device reads the data and, based on the read information, reproduces the video data or the like. By executing the reproduction of the recording information data, the recording and the reproduction of the disc are performed.

[0004] However, as described above, since high-quality and large-capacity copying can be easily performed, a copy for preventing illegal or illegal copying of recorded information data such as video / audio data and computer programs. The development of protection technology has become an important issue.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide an optical recording medium which makes it impossible to illegally record and reproduce information data.

[0006]

An optical recording medium according to the present invention is an optical recording medium having a groove track and a land track, wherein at least a part of the groove track has a divided intermittent structure. Have.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 3 is a perspective view showing the structure of a recording surface of a conventional recordable optical recording medium, taking a DVD-RW as an example. In FIG. 3, an optical disk (DVD
-RW) 11 is a phase change material as the data recording layer (e.g., the information data with a multi-layer 15 composed of the protective layer of the recording layer and glassy sandwiching the composed of GeSbTe or the like) (ZnS-SiO ₂₎ A rewritable phase-change type optical disc having a groove track 12 as an information recording track.
And a land track 13 as a guide track for guiding a light beam (B) such as a laser beam as a reproduction light or a recording light on the groove track 12. Further, it has a reflective layer 16 for reflecting the light beam (B) when reproducing recorded data, and an adhesive layer 19 for adhering these to a transparent substrate (polycarbonate) 18. Further, a transparent film (polycarbonate) for protecting the light beam (B) on the incident surface side thereof.
17 are provided. The land track 13 has pre-pits 14 corresponding to pre-information (pre-recorded information). The pre-pits 14 carry pre-information used by the information recording / reproducing apparatus at the time of recording / reproducing, that is, an address for recognizing a position on the groove track 12 and synchronization information, and are formed in advance before the optical disc 11 is shipped. Things.

Further, in the optical disk 11, the groove track 12 is wobbled at a frequency corresponding to the disk rotation speed. The wobbled groove tracks 12 are formed before shipping the optical disk 11 in the same manner as the pre-pits 14 described above. When recording information data (information information other than pre-information, such as image information to be originally recorded; the same applies hereinafter) is recorded on the optical disk 11, the wobbling frequency of the groove track 12 is extracted by an information recording device. The rotation control of the optical disk 11 is performed at a predetermined rotation speed, and pre-information is obtained in advance by detecting the pre-pits 14. Based on the pre-information, the optimal output of the light beam (B) as the recording light is set, and the recording is performed. Address information or the like indicating the position on the optical disk 11 where the information data is to be recorded is obtained, and the record information data is recorded at the corresponding recording position based on the address information.

At the time of recording the recording information data, the light beam (B) is irradiated so that the center thereof coincides with the center of the groove track 12, and the recording information pit corresponding to the recording information data is formed on the groove track 12. The recording information data is recorded by forming. At this time, as shown in FIG. 3, the size of the light spot (SP) is partially not only the groove track 12 but also the land track 13.
Is also set to be irradiated.

Using the reflected light of a part of the light spot (SP) applied to the land track 13, for example, a push-pull method (by a dividing line parallel to the tangential direction of the groove track 12, that is, the rotation direction of the optical disk 11). By a push-pull method (hereinafter, referred to as a radial push-pull method) using divided photodetectors, pre-information is detected from the pre-pits 14 and the pre-information is obtained, and a wobble signal is extracted from the groove track 12. Thus, a recording clock signal synchronized with the rotation of the disk is obtained.

Next, a recording format of pre-information recorded in advance on the optical disk 11 will be described with reference to FIG. In FIG. 4, the upper part shows the recording format of the recording information data, and the lower part shows the wobbling state of the groove track 12 (the plan view of the groove track 12) for recording the recording information data. The upward arrow during the wobbling state of the track 12 schematically indicates the position where the prepit 14 is formed. Here, in FIG. 4, the wobbling state of the groove track 12 is shown using an amplitude larger than the actual amplitude for easy understanding. Note that the record information data is recorded on the center line of the groove track 12.

As shown in FIG. 4, recording information data recorded on the optical disk 11 is divided in advance into sync frames as information units. One recording sector is formed by 26 sync frames, and one EC is formed by 16 recording sectors.
A C block is formed. One sync frame has a length of 1488 times (1488T) a channel bit length (hereinafter, referred to as T) defined by a recording format when recording the recording information data.
Further, the leading 32T length portion of one sync frame is used as synchronization information SY for synchronizing each sync frame.

On the other hand, the pre-information recorded on the optical disk 11 is recorded for each sync frame. Here, when pre-information is recorded on the optical disk 11 by the pre-pits 14, the synchronization signal in the pre-information is shown on the land track 13 adjacent to the area where the synchronization information SY in each sync frame in the recording information is recorded. As a result, one pre-pit 14 is always formed,
On the land track 13 adjacent to the first half of the sync frame other than the synchronization information SY, 2 or 1 pre-pits 14 are formed to indicate the contents of the pre-information to be recorded. However, the pre-pit 14 may not be formed in the first half of the sync frame other than the above depending on the contents of the pre-information to be recorded.) At this time, usually, pre-pits 14 are formed only in even-numbered sync frames (hereinafter, referred to as EVEN frames), and pre-information is recorded (exceptions will be described later). That is, in FIG. 4, the pre-pit 14 is formed in the EVEN frame (indicated by the solid line upward arrow in FIG. 4), but the pre-pit 14 is not formed in the ODD frame adjacent thereto. More specifically, EV
When the pre-pits are formed in the EN frame, all the pre-pits 14 (pre-pits B2, B1, and B0.) In the sync frame at the head of the recording sector.
Here, each of the pre-pits B from the beginning of the sync frame
2, B1 and B0. ) Are formed, and in a sync frame other than the head of the recording sector, when pre-information to be recorded in the sync frame is “1”, pre-pits B2 and B0 are formed, and information to be recorded is “0”. In this case, only the pre-pit B2 is formed. When a pre-pit is formed in an ODD frame, pre-pits B2 and B1 are formed in a sync frame at the head of the recording sector, and in a sync frame other than the head of the recording sector, the same as in the case of the EVEN frame. The same is true. That is, the pre-pit 14 is composed of the pre-pit trains B2, B
1, the meaning differs depending on the pattern of B0.

The pre-pit 14 to be formed in the sync frame of the EVEN frame / ODD frame is determined depending on the position of the pre-bit 14 previously formed on the adjacent land track. That is, the pre-pits 14 are usually formed in the EVEN frame. However, when the pre-pits 14 are formed in the EVEN frame, the pre-pits 14 on adjacent land tracks formed in advance are close to each other in the radial direction of the optical disc 11. Then, pre-pits 14 are formed in the ODD frame. By forming in this manner, the pre-pit 1 is located at the adjacent land track position.
Since the number 4 does not exist, the influence of crosstalk can be reduced in detecting the pre-pit 14.

On the other hand, the groove track 12 is wobbled at a constant wobbling frequency f0 of 140 kHz (frequency at which eight wobble signals are included in one sync frame) over all sync frames. Then, in the information recording apparatus, by extracting the constant wobbling frequency f0, a signal for controlling the rotation of the spindle motor is detected, and a recording clock signal is generated.

Next, a first embodiment of the present invention will be described in detail with reference to FIG. FIG. 5 is a plan view schematically showing the groove track 12 and the land track 13 of the control data section in the lead-in area. First, the groove track 12 has three pre-pits 14
Except for the vicinity of the pre-pit row composed of A, 14B, and 14C, it is formed as a portion having the same depth (same plane) as the land track 13, that is, as an intermittent groove track divided by a non-groove forming portion. The groove track 12 is produced by, for example, 8/16 modulating the cutting light beam at the time of groove cutting, and turning the output power ON-OFF (duty ratio is about 50%). That is, the groove track 12 has an intermittent structure divided by a signal of the same frequency band as a recording RF signal (a recording signal after 8/16 modulation) to be recorded on the optical disc. This means that the lengths of the individual groove portions and the non-groove-formed portions (hereinafter, referred to as mirror portions) are equivalent to the lengths and pit intervals of pits formed by information recording. That is, each of the groove portions corresponds to a mark (or space) of the information data.

On the other hand, pre-pits 14A, 14B, 14C
In a track to be traced when reading is performed, a continuous groove 12A adjacent to at least all of the prepits 14A, 14B, and 14C is formed in a sync frame including these prepits. That is, the groove 12A is at least the beginning of the pre-pit row in the tracking direction (the beginning of the pre-pit 14A).
To the end of the pre-pit row (the end of the pre-pit 14C). In this embodiment, the pre-pits 14A, 14B, 14
Another continuous groove 12B adjacent to the pre-pits 14A, 14B, 14C across C is formed.

When reproduction is performed after recording some 8/16 modulated information on the intermittent groove track having the above structure, the RF signal reproduced from the intermittent groove track has a small amplitude except for the area of the groove 12A. It cannot be read. This is because the intermittent (ON-OFF) of the groove track itself is in the same frequency band as the recorded RF signal, and thus interferes with each other. On the other hand, in the regions where the pre-pits 14A, 14B and 14C are formed, signal interference does not occur due to the continuous grooves 12A and 12B, so that the pre-information signal can be read. In addition, in the area of the groove 12A, it is necessary to be able to read other control signals (tracking error signal, wobble signal) other than the pre-pit signal. As mentioned above, about 50 for intermittent groove tracks
Since the groove exists at a duty ratio of%, the levels of the push-pull tracking error signal and the wobble signal are about 50% of the continuous groove, but sufficient tracking control is possible.

Therefore, even if the control data is recorded in the control data portion by forming the groove tracks intermittently in the control data portion of the lead-in area except for the region adjacent to the pre-pit,
During reproduction, the level of the reproduced RF signal in this section becomes low, and as a result, reproduction of control data becomes impossible. That is, it is impossible to reproduce recorded information data such as image information to be recorded and reproduced originally, thereby preventing unauthorized copying. In addition, as a method for avoiding copy protection when copying is properly performed on the recording medium, various methods such as hardware or software such as an avoidance device and a computer program can be adopted.

Next, a second embodiment of the present invention will be described in detail with reference to FIG. FIG. 6 is a plan view schematically showing the groove track 12 and the land track 13 of the control data section in the lead-in area. This embodiment is different from the first embodiment in that the pre-pit 14
A point that at least a region adjacent to all regions of the pre-pits 14A, 14B, and 14C is formed as a continuous mirror portion 22A on a track to be traced when reading A, 14B, and 14C. That is, the mirror unit 22
A is formed continuously from at least the beginning of the pre-pit 14A in the tracking direction to the end of the pre-pit 14C. In the present embodiment, the pre-pits 14A, 14B, and 14C are further sandwiched between the pre-pits 14A, 14B, and 14C.
Another mirror unit 22B adjacent to A, 14B, and 14C is configured.

Therefore, in the same manner as in the first embodiment, with the above configuration, the reproduced RF signal from the recording area of the intermittent groove track can be turned ON-O of the groove track itself.
Reading is not possible due to the interference between the FF and the recorded RF signal. On the other hand, in the areas adjacent to the pre-pits 14A, 14B and 14C, the pre-information can be read by the continuous mirror sections 22A and 22B.

It is obvious that the continuous groove and the continuous mirror section of the first and second embodiments may be used in combination. For example, the pre-pits 14A, 14B, 14
On a track to be traced when reading C, at least a continuous groove 12A adjacent to all regions of the pre-pits 14A, 14B, and 14C is formed.
Pre-pits 14A, 14 sandwiching 4A, 14B, 14C
The mirror portion 22B may be formed adjacent to B and 14C.

Next, a third embodiment and a fourth embodiment of the present invention will be described with reference to FIGS. FIGS. 7 and 8 are plan views schematically showing the groove track 12 and the land track 13 of the control data section in the lead-in area. As shown in FIG. 7, the third embodiment is different from the above-described embodiment in that the pre-pit 14
At least the pre-pits 14A, 14B, 14
The point is that a continuous groove 12A adjacent to all the regions C is formed. Even in such a configuration, the pre-information can be read because the continuous groove 12A does not cause signal interference in this section.

FIG. 8 shows a case where two pre-pits 14 are formed in a sync frame other than the head of a recording sector (pre-pits B2 and B0 or pre-pits B0).
2 and B1) are shown as examples. In this embodiment,
A continuous mirror portion 22A is formed in place of the continuous groove 12A. In this case, the same effect as in the third embodiment can be obtained.

Next, a fifth embodiment and a sixth embodiment of the present invention will be described with reference to FIGS. Fifth
The sixth embodiment differs from the above-described embodiment in that only one pre-pit 14A is formed. Even in these cases, at least the pre-pit 14A is included in the track traced when reading the pre-pit 14A.
A signal is formed by forming a continuous groove 12A (FIG. 9) or a continuous mirror portion 22A (FIG. 10) continuous from the start to the end of the pre-pit 14A in the tracking direction, that is, adjacent to all sections where A is formed. Pre-information can be read while avoiding interference.

Next, a seventh embodiment of the present invention will be described below. As shown in FIG. 11, the control data section in the lead-in area is
And a land track 13. The groove track 12 is divided into a plurality of groove sections 12C by a mirror section 22C, as in the case of the above-described embodiment.

In this embodiment, each groove portion 12C
Consists of a basic pit portion 31 and an extension portion 32.
The basic pit section 31 has a pit length corresponding to a mark (or space) of information data. As a modulation method, for example, when 8/16 modulation for converting 8-bit data to 16-channel bit data is used, the minimum pit length of the basic pit portion 31 is 3T, and the maximum pit length is 11T. Here, T is the channel bit length at the time of recording, as described in the first embodiment.
When a pit having a length of 14T is used as the synchronization pattern, the maximum pit length is 14T.

First, in forming the groove track 12 by dividing it into a plurality of groove portions 12C, the duty ratio of all the basic pit portions 31 in the groove track 12 in the control data portion is substantially the same as in the above-described embodiment. It is determined to be 50%. Furthermore,
In this embodiment, in order to improve the light detection signal level in the push-pull method (hereinafter, simply referred to as a push-pull signal level), an extension 32 (groove forming part) having a predetermined length is added to each basic pit part 31. To form a groove portion.

FIG. 12 shows a change in the push-pull signal level with respect to the length of the extension 32. The push-pull signal level when no extension is added to the basic pit portion 31 is 0.142, but the push-pull signal level increases as the length of the extension increases. When the length of the extension is 3T, the push-pull signal level is improved to a sufficient level of 0.233. Although the push-pull signal level is increased by lengthening the extension part, there is a trade-off in which if the length is too long, the effect of making illegal recording and reproduction on the groove part 12C impossible is reduced.

The length of the extension 32, the basic pit 3
The duty ratio of 1 and the like can be appropriately changed in consideration of the light detection signal level and the like. In the above-described embodiment, the length of the extension portion is fixed. However, the length of the extension portion 32 may be determined according to the length of the mirror portion 22C following the basic pit portion 31. For example, the length of the extension added to the basic pit may be a predetermined ratio of the length of the mirror following the basic pit. Further, it may have a pre-pit having the same configuration as that of the first to sixth embodiments.

Therefore, according to the present invention, by adding an extension portion 32 of a predetermined length to each basic pit portion 31, it is possible to prevent improper recording / reproduction, improve the push-pull signal level, and improve the tracking performance. Can be. still,
The continuous groove or the continuous mirror section shown in the above-described embodiment may be used in an appropriate combination.

In the above embodiment, the case where the groove track 12 is divided by a signal having the same band as the recording RF signal of the optical disk has been described.
The signal may be divided by a signal including a part of the band of the F signal. Furthermore, in the above-described embodiment, the DVD-RW is described as an example of the optical recording medium. However, the present invention is not limited to this, and can be applied to other optical recording media such as a DVD-R.

[0033]

As is apparent from the above, according to the present invention, an optical recording medium capable of preventing illegal recording information data copying by forming groove tracks intermittently is realized. it can. In addition, by providing an intermittent groove track having a structure according to the present invention, not limited to the control data section in the lead-in area, it is possible to prohibit reading of a reproduced RF signal from an arbitrary portion of the optical disk.

[Brief description of the drawings]

FIG. 1 is a diagram showing a layout of physical sectors in a recording surface radial direction of a recordable or rewritable DVD.

FIG. 2 is a diagram showing a configuration of a lead-in area and a control data area.

FIG. 3 is a perspective view showing a structure of a control data area in a conventional DVD-RW.

FIG. 4 is a diagram for explaining a frame configuration and a pre-pit of a physical sector.

FIG. 5 is a plan view schematically showing a groove track and a land track of a control data section according to the first embodiment of the present invention.

FIG. 6 is a plan view schematically showing a groove track and a land track of a control data section according to a second embodiment of the present invention.

FIG. 7 is a plan view schematically showing a groove track and a land track of a control data section according to a third embodiment of the present invention.

FIG. 8 is a plan view schematically showing a groove track and a land track of a control data section according to a fourth embodiment of the present invention.

FIG. 9 is a plan view schematically showing a groove track and a land track of a control data section according to a fifth embodiment of the present invention.

FIG. 10 is a plan view schematically showing a groove track and a land track of a control data part according to a sixth embodiment of the present invention.

FIG. 11 is a plan view schematically showing a configuration of a groove track and a land track of a control data section according to a seventh embodiment of the present invention.

12 is a graph showing a change in a push-pull signal level with respect to a length of an extension shown in FIG. 11;

[Description of Signs of Main Parts]

 DESCRIPTION OF SYMBOLS 11 DVD-RW 12 Groove track 12A, 12B Continuous groove 12C Groove part 13 Land track 14, 14A, 14B, 14C Prepit 15 Multi-layer 16 Reflective layer 17 Transparent film 18 Transparent substrate 19 Adhesive layer 22A, 22B, 22C Mirror part 31 Basic Pit 32 Extension

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akifumi Taniguchi 4-2610 Hanazono, Tokorozawa-shi, Saitama F-term (reference) in Pioneer Corporation Tokorozawa Plant 5D029 PA03 WA12 5D090 AA01 BB03 BB05 CC14 FF09 GG01

Claims (3)

[Claims] 1. An optical recording medium having a groove track and a land track, wherein at least a part of the groove track has a divided and intermittent structure. 2. The optical recording medium according to claim 1, wherein the groove having an intermittent structure is formed in a control section for recording control information of a lead-in area. 3. The optical recording medium according to claim 1, wherein the groove having an intermittent structure has an intermittent structure divided by a signal in the same frequency band as an RF signal to be recorded.