JP3070414B2 - Optical disc and reproducing apparatus therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk such as a CD-ROM (compact disk ROM) in which information such as a TV (television) game is stored, and whether or not the optical disk is legitimate. The present invention relates to a reproducing apparatus for preventing copying.

[0002]

2. Description of the Related Art At present, most optical disks such as CD-ROMs are formatted according to published standards such as "ISO9660". Various software such as TV games should be protected from illegal copying from the viewpoint of copyright protection. However, if the software is formatted according to the published standards as described above, Restrictions are added to copy protection measures.For example, a copy protection code is recorded in advance, and if there is the code at the time of reproduction, it is a legitimate disk, and if there is no code, it is regarded as an illegal copy disk and the reproduction is performed. Stopping is performed.

[0003] However, in such an illegal copy prevention measure, if a copy machine for copying the data described in the logical standard as a whole is manufactured, it is possible to easily copy the data, which is not a very effective method.

In the case of CD-ROMs which have been commercialized relatively quickly, most of the CD-ROMs have been produced by making their own standards before the above-mentioned standards have been established.
D-ROMs conforming to this standard will be mainstream.
Then, CDs with weak copy protection are circulated, and illegal copying is circulated, and the same situation is likely to occur especially for CD-ROM type game software.

Therefore, as a copy prevention measure for a new CD, for example, as shown in Japanese Patent Application Laid-Open No. Sho 61-178732, "pseudo pits" of pits smaller than normal pits are formed on a disk, and the pseudo pits are detected. By doing so, the composite output is deformed to prevent copying.

[0006]

However, as described above, the format can be written in accordance with the standard, the code for copy protection can be written, the code can be written according to the original standard, or as described in the above publication. A copy machine that reads data in lower-level frame units and copies it to a CD-write-once disk, etc., even if writing including pseudo-pits is not possible with software that reads ordinary CD-ROMs. According to this, there is a problem that any disk is copied.

In particular, when forming a pseudo pit, not only the pseudo pit is formed smaller than the normal pit and mass production is required, but also strict management is required.
Since small pseudo pits must be detected, the detection reliability is also reduced.

The present invention focuses on the above problems,
The present invention has been made to solve this problem effectively, and an object of the present invention is to provide an optical disk capable of reliably preventing illegal copying and a reproducing apparatus therefor.

[0009]

A first aspect of the present invention is defined by the first aspect.
According to the invention, in an optical disc having a track formed by arranging a large number of pit rows concentrically or spirally, most of the tracks in the information area of the optical disc have an identification portion for copy prevention by a normal track pitch. In this case, some tracks are formed at a track pitch different from the normal track pitch.

According to a second aspect of the present invention, in the optical disk reproducing apparatus defined in the first aspect, a pickup section for reading information by irradiating the optical disk with a laser beam, and based on information from the pickup section. A tracking error detection unit that generates a tracking error signal, a tracking processing unit that drives and controls a driver of the pickup unit based on the tracking error signal, and a lens of the pickup unit in the radial direction of the optical disc, A lens kick pulse generator that generates a lens kick pulse that moves a track portion of the track pitch by a predetermined distance; a track counter that counts the number of tracks crossing when the lens kick pulse is generated; Track address and previous A storage unit for storing addresses of tracks having different track pitches, a comparison unit for comparing the count values of the track counters at the two addresses, and whether or not the optical disc is legitimate based on the comparison result of the comparison unit And a control unit for judging whether or not there is a difference.

According to a third aspect of the present invention, in the optical disk reproducing apparatus defined in the first aspect, a pickup section for reading information by irradiating the optical disk with a laser beam, and based on information from the pickup section. A tracking error detection unit for generating a tracking error signal, a tracking processing unit for driving and controlling a driver of the pickup unit based on the tracking error signal, and a lens of the pickup unit in a radial direction of the optical disc. A lens kick pulse generating unit for moving the same distance as the pitch, an address recognizing unit for recognizing an address from read information of the pickup unit, a storage unit for storing addresses of tracks having different track pitches, and performing a lens kick. Of address before and after A continuity verifying unit for verifying, in which the verification unit of the verification result said optical disk based on the constructed as a control unit for determining whether the regular ones.

According to a fourth aspect of the present invention, in the optical disk reproducing apparatus according to the first aspect, a pickup section for reading information by irradiating the optical disk with a laser beam, based on the information of the pickup section. An address recognizing unit for recognizing an address, a storage unit for storing addresses immediately before and after a track having a different track pitch, and a measuring unit for measuring a rotation cycle of the optical disc in a portion of the different track pitch. A comparison unit that compares the rotation cycle measured by the measurement unit based on a predetermined formula; and a control unit that determines whether the optical disc is legitimate based on the comparison result of the comparison unit. It is what was constituted.

[0013]

According to the first aspect of the present invention, a copy prevention identification portion having a track pitch different from the normal track pitch is formed in a part of the information area of the optical disk. It is possible to determine whether the optical disc is a proper optical disc.

According to a second aspect of the present invention, a tracking error signal is obtained by, for example, a tracking error detection unit based on the information read by the pickup unit, and the tracking error signal is input to the tracking processing unit. The tracking processing unit performs tracking control of the pickup unit based on the error signal.

When determining whether or not the optical disk is legitimate, the control unit drives the lens kick pulse generation unit based on the address information in the storage unit to perform a predetermined distance over the abnormal track pitch. The pickup section jumps only, and the number of tracks passed at that time is counted by a track counter. Similarly, the pickup unit is caused to jump by the same jump amount in the normal track pitch portion, and the number of tracks passed at that time is counted by the track counter.

Then, these two count values are compared by the comparing section, and based on the result of the comparison, the control section determines whether or not the optical disk is a legitimate optical disk. For example, if the two count values are significantly different, the control unit recognizes that the optical disk includes different track pitches and determines that the optical disk is a legitimate optical disk.

According to a third aspect of the present invention, a tracking error signal is obtained by, for example, a tracking error detection section based on the information read by the pickup section, and the tracking error signal is input to the tracking processing section. The tracking processing unit performs tracking control of the pickup unit based on the error signal.

To determine whether the optical disk is legitimate, the control unit drives the lens kick pulse generation unit based on the address information in the storage unit to jump the pickup unit by the same distance as the normal track pitch. Let it.
At this time, if the legitimate optical disk is used, there is no track at the position where the jump occurred, and the track could not be tracked and runaway.The pickup unit reached a track with a significantly different address. Become. On the other hand, in the case of an irregular optical disk in which the track pitch is the same over the entire surface of the disk, when the pickup unit jumps, the next track is accessed without runaway, and substantially continuous addresses are read. Will be. The address information before and after the jump is recognized by the address recognition unit, and the continuity verification unit verifies whether the recognized addresses are substantially continuous. Then, based on the result of the verification, the control unit determines whether the optical disk is a legitimate optical disk.

The fourth invention is, for example, a CLV (Const
In an “ant Linear Velocity” method, the address recognition unit obtains an address at that time based on information read by the pickup unit.

When judging whether the optical disk is legitimate or not, the control unit performs tracking immediately before and after a track portion having a different track pitch based on the address information of the storage unit, and controls each of the optical disks at this time. Is measured by a measuring unit. At this time, since the track pitch is large in the case of a regular optical disk, even if the same number of addresses advances as compared with the case of an irregular optical disk, the pickup unit moves largely in the disk radial direction,
As a result, the rate of increase of the rotation period increases. The measurement value of the measurement unit is calculated by the comparison unit based on a predetermined formula, and the increase rate is calculated and compared with a predetermined value. As a result, when the increase rate is large as described above, the control unit Will be recognized as the optical disk.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disk and a reproducing apparatus for the same according to the present invention will be described below in detail with reference to the accompanying drawings. FIG.
FIG. 2 is a perspective view showing the optical disc according to the first invention, FIG. 2 is a view showing a track portion having a track pitch different from the normal track pitch of the optical disc shown in FIG. FIG. 4 is a schematic block diagram showing an optical disk reproducing apparatus according to the second invention, and FIG. 4 is a waveform diagram showing signal waveforms when judging whether or not the optical disk is normal.

In FIG. 1, an optical disc 1 has a track T in which a large number of pit rows are arranged concentrically or spirally.
Most of the tracks in the information area 2 of the optical disk 1 are formed with a normal track pitch P to form a normal track pitch area 3A, and a part of the track substantially at the center in the disk radial direction is the normal track pitch area 3A. Is formed with a track pitch 3P different from, for example, three times the track pitch P to form an abnormal track pitch area 3B as an identification unit for copy protection. In FIG.
In the abnormal track pitch area 3B, two tracks are formed with a track pitch 3P therebetween, and a mirror surface portion 4 is formed in a portion corresponding to the width of the track pitch 3P so that the track cannot be detected.

The width L of the abnormal track pitch area 3B
1 is desirably set to a small length that cannot be easily visually recognized, for example, about several tens of μm. An optical disk having tracks partially having different track pitches is regarded as a regular optical disk, and an optical disk having tracks having the same pitch over the entire surface of the disk is regarded as an irregular optical disk.

The number of tracks in the abnormal track pitch area 3B is not limited to two, and may be further increased. The track pitch 3P in the area 3B is three times the normal track pitch P. However, the pitch may be set to be larger than this, or may be set to be smaller than the normal track pitch P.

The reproducing apparatus according to the present invention is used for reproducing the optical disk. The reproducing apparatus has a judgment function for judging whether or not the optical disk is legitimate. First, the optical disk 1 is installed and fixed on a turntable (not shown) rotatable by a spindle motor 5.

The pickup section 6 has an optical system having a laser oscillator and a lens 7 inside, and reads out recorded information on the optical disk surface by using a laser beam 8. The lens 7 is movable in a focus direction and a tracking direction by a lens actuator 9. The drive control of the pickup unit 6 and the lens 7 is performed by a driver unit 11 that operates based on a command from the tracking processing unit 10.
Is a feed driver 12 for moving the entire pickup section 6 and a lens driver 13 for moving only the lens 7.
have. Further, the tracking processing unit 10 has a feature of the present invention that generates a lens kick pulse for forcibly instantaneously moving the lens 7 in the radial direction of the optical disc 1 at a constant speed faster than at the time of normal tracking. The lens kick pulse generator 14 is connected, and the output is input to the lens driver 13 via the adder 15. The lens kick pulse generator 14 generates a pulse that can jump the abnormal track pitch area 3B of the optical disc 1 at a constant speed and a predetermined distance.

The output of the pickup section 6 is connected to a data detection section 16 and a tracking error detection section 17, respectively, and the data signal is transmitted to an RF processing circuit 1 for processing data.
The tracking error signal is input to the tracking processing unit 10. The RF processing circuit 18
Is a portion for reproducing a video signal, an audio signal, and the like, and has a PLL (Phase Lock) (not shown) therein.
ed-Loop) circuit, EFM (Eight to F)
ourteen Modulation) decoder, C
IRC (Cross Interleaved Reed)
-Solomon Code), a code error correction unit, an address decoder 23 and the like.

The tracking error signal is also input to the track counter 19, so that the number of tracks crossed when a tracking error occurs can be counted. Although not shown, control of the focus direction of the lens is, of course, also performed.

The output of the counter 19 is input to the tracking processing unit 10 and also to a control unit 20 which controls the operation of the entire apparatus, for example, a microcomputer or the like.

The control unit 20 includes a track counter 1
A comparison unit 21 for comparing the count value of 9 is connected, and based on the result, the control unit 20 determines whether or not the optical disc is legitimate.

The control unit 20 includes the optical disc 1
A storage unit 22 such as a ROM for storing address information and the like regarding the abnormal track pitch area 3B having different track pitches is connected. Specifically, the address information stores an initial address a2 in the abnormal track pitch area 3B of the optical disk as shown in FIG. 4, and the lens kick pulse causes the lens to move within the abnormal track pitch area 3B by a predetermined distance. The jump distance of the lens is set so that the lens jumps only to reach address a3, for example. The amount of sham is usually several times, preferably eight times or more, the track pitch in order to increase the detection accuracy, and is set to a range not excessively exceeding the width of the abnormal track pitch area 3B. The storage unit 22 also stores in advance an address a1 indicating a starting point at which the lens 7 should jump in the normal track pitch area 3A of the optical disk as described above.

Next, the operation of the present embodiment configured as described above will be described. First, a laser beam 8 condensed from a pickup unit 6 via a lens 7 is applied to the optical disk surface, and recorded information is read out by the reflected light. Based on the read information, a data signal is generated by the data detection unit 16 and supplied to the RF processing circuit 18 where normal signal processing is performed. On the other hand, a tracking error signal S 1 is generated in the tracking error detecting section 17 and is supplied to the tracking processing section 10.

On the basis of the tracking error signal S1, the tracking processing section 10 controls the driving of the pickup section 6 and the lens 7 via the feed driver 12 and the lens driver 13 to track the track on the optical disk surface. It is needless to say that the lens is properly focused by the operation of a focus processing system (not shown).

A description will be given of a case where an optical disk is checked in a device which operates generally as described above.
First, the pickup unit 6 is moved to seek an address a1 in the normal track pitch area 3A which is stored in the storage unit 22 in advance (see FIG. 4). The lens kick pulse signal S is operated by operating the lens kick pulse generator 14.
2 is generated and added to the lens driver 13 via the adder 15. This waveform is a waveform that increases linearly, and can be moved by jumping the lens at a constant speed.

Thus, the lens 7 jumps in the radial direction of the disk by an amount corresponding to the magnitude of the lens kick pulse signal S2, and the number of tracks passed at that time is counted by the track counter 19. The count value at this time is, for example, C1. Since the jump position of the lens is the normal track pitch area 3A, the count value C1 is the number of tracks corresponding to the jump amount. This count value C1 is stored in the control unit 20. It is most preferable to set the jump by the lens kick pulse so that the jump from the innermost track to the outermost track of the abnormal track pitch area.

Next, the pickup section 6 is moved again, and the address a2 in the abnormal track pitch area 3B, which is an identification section for copy protection, stored in the storage section 22 in advance.
(See FIG. 4), and the control unit 2
The lens kick pulse generating unit 14 is operated again according to 0 and the command from the tracking processing unit 10 to generate the lens kick pulse signal S2 again, thereby causing the lens 7 to jump in the disk radial direction. In FIG. 4, the address of the point at which the lens 7 has jumped is represented as a3.

The jump amount at this time is determined by the previous address a1
It is the same as when jumping from. The number of tracks passed at the time of this jump is also counted by the track counter 19,
This count value is represented, for example, as C2. In this case, since the track pitch in the abnormal track pitch area 3B is larger than the other parts, the count value C2 is considerably smaller than the previous count value C1, for example, the relationship between the two pitches P and 3P. According to this embodiment, the value is equal to or less than 1/2.

Next, the comparator 21 compares the count values C1 and C2 measured by the track counter 19. In this case, a predetermined threshold value, for example, 1/2 is set in advance between these two count values, and it is determined whether or not the count value C2 is smaller than 1/2 of the count value C1, and the result is controlled. Send to section 20. Here, if C2 <C1 ・, the control unit 20 can determine that the abnormal track pitch area 3B described above exists on the disk surface, and thus recognizes that the disk is a legitimate disk, and conversely, C2 <C1 ・. If it is not 1/2, for example, if C2 ≒ C1, it can be determined that the portion jumped from the address a2 is formed only by the track having the normal track pitch, so that the disc is recognized as an irregular disc. When the disc is recognized as an unauthorized disc, measures such as disc exclusion are taken.

Here, the kick pulse width (driving time)
Is set to a length that can count tracks including the eccentricity of one rotation of the disk. The reason for counting the number of track crossings by jumping once in the normal track area is to count and compare the number of track crossings including disk eccentricity.

The above operation will be described with reference to the flowchart shown in FIG. First, it is determined in S1 whether an optical disk has been set. If YES, it is determined whether the disk is a CD-ROM or DA (digital audio) (S2).

If the disc is a DA, the DA reproduction process is performed as it is (S3). If the disc is a CD-ROM, the pickup unit is moved to the normal track pitch area 3 (S3).
A predetermined address a1 in A is sought (S4), and the track counter is cleared (S5).

Next, in this state, the lens kick pulse generator 14 is operated to generate the lens kick pulse signal S2, and the lens 7 is jumped (S6). The value of the track counter 19 counted at the time of the jump is set as a count value C1 (S7) and stored.

Next, the pickup unit 6 seeks to a predetermined address a2 in the abnormal track pitch area 3B (S8), and clears the track counter again (S8).
9).

Next, in this state, the lens kick pulse generator 14 is operated again to generate the lens kick pulse signal S2, and the lens 7 jumps (S10). The value of the track counter 19 counted at the time of this jump is set as a count value C2 (S11) and stored.

Next, the count values C2 and C1 are compared taking into account a threshold value, for example, 1/2, and it is determined that C2 <C1１ (S12). In the case of YES, since it can be determined that the optical disc includes the abnormal track pitch area 3B, this optical disc is recognized as a regular disc (S13), the check operation ends, and normal reproduction processing starts. Is done. On the other hand, if NO in S12, since it can be determined that the optical disc does not include the abnormal track pitch area 3B, this optical disc is recognized as an unauthorized disc (S14), and the disc is ejected. Is performed (S15).

As described above, according to the present invention, it is determined whether or not a part having a different track pitch, which is an identification part for copy protection, exists in a part of the track of the optical disk, thereby determining whether the track is legitimate or illegal. Can be determined.

When the optical disk of the present invention is read out by a normal CD-ROM drive or the like in order to copy, the duplicated disk can be manufactured by copying it onto a CD write-once disk or the like because the main data is not modified. However, since the data information can be duplicated but the abnormal pitch structure cannot be duplicated, if this copy disc is set on the reproducing apparatus of the present invention, the abnormal track pitch cannot be detected, and the reproduction is stopped.

Also, unlike the conventional method in which a copy protection code is written in the main data, in the case of the present invention, since the data is not devised, it cannot be recognized by data analysis or the like, and an abnormal track is recorded in a very narrow area. Since the pitch area is provided, it is difficult to visually recognize the pitch area.

Further, in order to duplicate an optical disk having this kind of abnormal track pitch area, a significant modification must be made to the disk manufacturing apparatus, which requires cost and time. Have difficulty. Further, copying is not possible even with a CD write once device owned by a general user.

An optical disk having an abnormal track pitch area can be reproduced only by the reproducing apparatus of the present invention. However, there is no need to use a game application optical disk other than the game machine, so that there is no practical problem.

Next, an optical disk reproducing apparatus according to the third invention will be described with reference to FIG. FIG. 6 is a schematic block diagram showing an optical disk reproducing apparatus according to the third invention. In this figure, the same parts as those in FIG.

In the reproducing apparatus according to the second aspect, the jump amount of the lens moved by the lens kick pulse generated by the lens kick pulse generating section 14 is
Although the setting is made to be several times or more of the normal track pitch P, in the third invention, the point that the amount of jump is set to be the same distance as the normal track pitch P and the comparison unit 21 are different. Instead, a main difference is that a continuity verifying unit 24 that verifies the continuity of addresses before and after the lens kick is provided.

That is, the lens kick pulse generator 25 shown in FIG. 6 can generate a so-called dipulse lens kick pulse capable of performing a lens kick by the same distance as the normal track pitch P. I have. The storage unit 22 stores the address a4 (see FIG. 7) of the innermost track of the abnormal track pitch area as a point at which the lens kick starts.

A continuity verifying unit 2 provided in place of the comparing unit
Reference numeral 4 has a function of checking whether addresses before and after a jump due to a lens kick are substantially continuous or largely separated based on information from the address decoder 23. The control unit 20 determines whether the optical disk is a legitimate one. In other words, if the optical disk is a regular optical disk, the pickup unit that jumps into the abnormal track pitch area cannot run the track for a while without tracking because it cannot immediately recognize the track, and reaches the track whose address is far away. Will be. Therefore,
If there is no continuity in the address, it means that there is an abnormal track pitch area. Therefore, the control unit 20 recognizes that the optical disk is a regular optical disk. Of the optical disk.

The operation of the third invention will be described with reference to FIG. 7. First, the pickup unit 6 is caused to track the track in the normal track pitch area 3A, and the addresses a4, That is, when the beam spot reaches the position 26A on the innermost track of the abnormal track pitch area 3B, the controller 20 drives the lens kick pulse generator 25 to generate a lens kick pulse for one track jump. The beam spot jumps from position 26A to position 26B.
Here, if a track having a normal track pitch P is formed in the jump destination area, the beam spot goes to the adjacent track without any problem. However, when the optical disk has an abnormal track pitch area having a large pitch as in this optical disc, However, since this portion is a mirror surface portion 4, tracking cannot be performed because there is no pit, and a runaway occurs in search of a pit. As a result of this runaway, the beam spot moves to the track T which is three times the normal track pitch P apart.
1 will be tracked.

At this time, the addresses before and after the jump obtained by the address decoder 23 are stored in the control unit 20, and the continuity of the two addresses is verified by the continuity verification unit 24. As a result of the verification, the control unit 20 determines that a runaway has occurred if the two addresses are greatly separated and discontinuous, and recognizes that the optical disk is a regular optical disk. I do.

The above operation will be described with reference to the flowchart shown in FIG. First, it is determined in S1 whether or not an optical disk is set. If YES, it is determined whether the disk is a CD-ROM or DA (S2). Here, when the disc is DA, DA reproduction processing is performed as it is (S3), and when the disc is CD-ROM, the pickup unit is sought to a predetermined address a1 (S4), (S5).

Next, the lens kick pulse generator 25 is operated to generate a lens kick pulse signal S2 ', and the lens, that is, the beam spot is moved to the normal track pitch of one.
Jump is made by a distance corresponding to the pitch (S6). After the runaway or without runaway, the address of the pit of the track where the next beam spot is caught is a5 (S5).
7).

Then, the continuity verifying unit 24 verifies whether or not the difference between the two addresses a4 and a5 falls within a predetermined allowable continuity range value H based on the following equation (S8). a5> a4 ± H

In the case of YES, it is determined that the optical disk contains the abnormal track pitch area 3B due to runaway, the optical disk is recognized as a regular disk (S9), and normal reproduction processing is started. Is done. On the other hand, in the case of NO in S8, it is determined that the optical disk does not include the abnormal track pitch area 3B because it does not run away, and it is recognized that this optical disk is an illegal disk (S10). Then, the disc is ejected (S11).

As described above, according to the third aspect of the present invention, it is determined whether or not there is a portion having a different track pitch in a part of the optical disk, thereby determining whether the optical disk is legitimate or illegal. Thus, the same operation and effect as those of the above-described second invention device can be exhibited.

Next, an optical disk reproducing apparatus according to the fourth invention will be described with reference to FIG. FIG. 9 is a schematic block diagram showing an optical disk reproducing apparatus according to the fourth invention. In this figure, the same parts as those in FIG. FIG. 10 is a graph showing the relationship between the address and the rotation period. In the fourth invention device, whether or not the optical disk is a regular optical disk is determined by comparing the rate of change of the rotation period of the optical disk in the abnormal track pitch area based on a predetermined formula.

In FIG. 9, the servo processing unit 27 includes a focus unit 27A and a tracking unit 27B for controlling the drive of the pickup unit 6, and a driver unit 27C for controlling the drive of the spindle motor 5. Focusing and tracking, and properly adjusting the rotational speed of the optical disc, for example, CLV (Constant Linear Velo).
(City) method. The tracking processing unit 10, feed driver 12, lens driver 13 and the like shown in FIG. 3 correspond to the tracking unit 27B.

The storage unit 22 connected to the control unit 20 has
The addresses a4 and a5 of the tracks having different track pitches, that is, the tracks immediately before and immediately after the abnormal track pitch area 3B are stored, and the measuring unit 28 measures the rotation cycle of the optical disk at each of the addresses using the timer 29. . Further, the comparing unit 30 compares the measured rotation cycle based on a predetermined formula, and based on the comparison result, the control unit 20 determines whether the optical disc is a regular one.

Next, the operation of the apparatus configured as described above will be described. In the present embodiment, the rotation of the optical disk is controlled by the CLV method. Therefore, as shown in FIG. 10, as the address is updated and becomes larger from the inside to the outside of the disk, the rotation speed decreases and the rotation period increases. .

As described above, in this optical disk, the range from address a4 to address a5 is the abnormal track pitch area 3B, and the area before and after that is the normal track pitch area 3A. First, the pickup unit 6 is caused to seek immediately before the address a4 stored in advance, and the measurement unit 23 is sought.
Measures the rotation period of one rotation of the disk at this time based on information from the address decoder 23 and the timer 29. The rotation cycle at this time is defined as Ta.

Next, the pickup unit 6 is caused to seek immediately after the address a5 stored in advance, and the measuring unit 23 similarly measures the rotation cycle of one rotation of the disk at this time. The rotation cycle at this time is defined as Tc.

Here, since the track pitch from address a4 to address a5 is made larger than that of the other parts, when the same number of addresses advances as compared with the case where the entire surface of the disk has the same track pitch, The amount of movement of the pickup unit in the radial direction of the disk is large, and as a result, the rotation period Tc is considerably larger than the rotation period Tb of the disk having the same track pitch over the entire disk surface.

Therefore, the comparison unit 30 calculates the rate of change of the rotation cycle by, for example, the equation (Tc−Ta) / Ta, compares the rates, and determines the result by the control unit 20 to determine whether the disc is a valid optical disc. Can be determined.

Next, the above operation will be described with reference to the flow charts shown in FIGS. First, it is determined in S1 whether an optical disk has been set. If YES, it is determined whether the optical disk is a CD-ROM or DA (digital audio) (S2).

Here, if the disc is DA, the DA reproduction process is performed as it is (S3). If the disc is CD-ROM, the pickup unit 6 is moved to the abnormal track pitch area 3B based on the information in the storage unit 22. Address a immediately before
4 (S4), and the disc 1 in this portion is sought.
The rotation period of the rotation is measured (S5). Pickup unit 6
Is determined by looking at the output value of the address decoder 23.

Here, the procedure for measuring the rotation period will be described with reference to FIG. 12. First, the address currently accessed by the pickup unit 6 is read (SS1), and it is determined whether or not this address is the initial address (SS1). SS
2). Here, the initial address indicates, for example, the first sector of each track.

If the read address is not the initial address, the next address is sequentially read. If the read address is the initial address, the timer 29 of the control unit 20 is cleared and then started to measure the time (SS3). Subsequently, the address is read (SS4), and it is determined whether or not the address after one rotation of the disk, that is, for example, is the last sector of the track (SS5). Then, when the disk has made one rotation, the timer 29 is stopped, and the timer value at this time becomes the rotation cycle at the address a4, for example, T1 (SS6). Note that this rotation cycle T
a is temporarily stored and held.

After measuring the rotation cycle in this way, the flow returns to the flow shown in FIG. 11 again. Next, the pickup unit 6 seeks to the address a5 immediately after the abnormal track pitch area 3B (S6). The rotation cycle of the optical disk is measured by the same process as that described with reference to FIG.
7). The rotation cycle at the address a5 is defined as T2. If the optical disk is a regular one, the track pitch is large, so that the optical disk travels greatly in the radial direction of the disk, and the rotation cycle becomes larger than that of the normal track pitch. Then, the comparison unit 30 calculates, for example, the following equation (1) to determine the rate of change of the rotation cycle, and determines whether the rate of change is less than a predetermined set value H (S8).

(T2−T1) / T1 (1)

The predetermined value H is equal to the value obtained when the rotation cycle Tb at address a5 in the case of a disc (an irregular disc) in which all tracks are recorded at a fixed track pitch is given to the above equation (1). Disk rotation cycle T
What is necessary is just to select a value substantially intermediate between the values obtained when c is given in the above equation (1).

As a result of this judgment, when the value obtained by the equation 1 is equal to or larger than the set value H (YES), there is a part where the track pitch is partially increased in the track. Therefore, the control unit 20 recognizes that the disc is a regular disc (S9), and continues the reproduction operation as it is. On the other hand, if the value obtained by Expression 1 is smaller than the set value H (NO), it means that there is no part where the track pitch is partially increased, and thus the control unit 20 The disc is recognized as an irregular disc (S10), and copy prevention measures such as disc ejection operation are taken (S11).

As described above, by comparing the rate of change of the rotation cycle of a predetermined address of a part of the optical disk with the other part, the optical disk is determined to be a normal one or an irregular one such as a copy. It is possible to determine whether or not there is, and the same operation and effect as in the case of the second invention can be exhibited.

In the above embodiment, when two rotation periods are compared, the rate of change of the rotation period is determined.
The method is not limited to the above-described comparison method as long as it is possible to recognize whether or not the rotation period is changing linearly, and any comparison method may be used.

[0080]

As described above, according to the optical disk and the reproducing apparatus of the present invention, the following excellent operational effects can be obtained. According to the optical disc of the present invention, a track having a different pitch from that of the other part is formed in one part, and an identification unit for copy protection is provided. Therefore, by detecting this part, it is determined whether or not the disc is a legitimate optical disc. Information can be given. Unlike the conventional optical disk, which has a code written in the main data to prevent copy, the track pitch is partially changed, so not only is analysis difficult, but also it can be visually recognized using a microscope. It is difficult to do. Even if the surface of the optical disk is contaminated or scratched, it is possible to prevent the occurrence of a detection error since it is not code information based on the pits affected by these. Further, according to the reproducing apparatus of the present invention, when a track having a pitch different from that of another part is formed in a part of the optical disk, this can be recognized, so that it is determined whether the optical disk is legitimate. In addition, it is only necessary to change the software of each playback device or add a kick pulse generator as hardware, and the track counter and timer are usually built in the IC, so that the cost increases. Can be adopted without inviting.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an optical disc according to a first invention.

FIG. 2 is an enlarged view of a portion A shown in FIG.

FIG. 3 is a schematic block diagram showing an optical disc reproducing apparatus according to a second invention.

FIG. 4 is a waveform diagram showing signal waveforms when judging whether or not the optical disc is legitimate.

FIG. 5 is a flowchart showing an optical disc checking process performed based on the second invention device.

FIG. 6 is a schematic block diagram showing an optical disk reproducing apparatus according to a third invention.

FIG. 7 is an explanatory diagram for explaining the movement of a beam spot when checking the optical disc.

FIG. 8 is a flowchart showing an optical disk checking process performed based on the third invention device.

FIG. 9 is a schematic block diagram showing an optical disk reproducing apparatus according to a fourth invention.

FIG. 10 is a graph showing a change in a rotation cycle with respect to an address at the time of checking the optical disc.

FIG. 11 is a flowchart showing an optical disc checking process performed based on the fourth invention apparatus.

FIG. 12 is a flowchart showing a process when a rotation cycle of the optical disc is obtained.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Information area, 3A ... Normal track pitch area, 3B ... Abnormal track pitch area (identification part for copy prevention), 4 ... Mirror surface part, 5 ... Spindle motor, 6 ... Pickup part, 7 ... Lens, 10 tracking processing unit, 11 driver, 12 feed driver, 13 lens driver, 14 lens kick pulse generating unit, 17 tracking error detection unit, 18 RF
Processing circuit, 19: track counter, 20: control unit, 2
DESCRIPTION OF SYMBOLS 1 ... Comparison part, 22 ... Storage part, 23 ... Address decoder (address recognition part), 24 ... Continuity verification part, 25 ... Lens kick pulse generation part, 27 ... Servo processing part, 28 ... Measuring part, 29 ... Timer, 30: comparison section, P: normal track pitch, 3P: different track pitch, S1: tracking error signal, S2: lens kick pulse signal.

Claims (4)

(57) [Claims] 1. An optical disk having tracks formed by arranging a large number of pit rows concentrically or spirally, most of tracks in an information area of the optical disk are formed at a normal track pitch, and some of the tracks are formed at a normal track pitch. An optical disc, wherein a track has an identification portion for copy prevention formed at a track pitch different from the normal track pitch. 2. A reproducing apparatus for an optical disk according to claim 1, wherein the optical disk irradiates a laser beam to the optical disk to read out information, and a tracking error detecting unit generates a tracking error signal based on the information of the pickup unit. A tracking processing unit that drives and controls a driver of the pickup unit based on the tracking error signal; and moves a lens of the pickup unit in a radial direction of the optical disc by a predetermined distance between track portions having different track pitches. A lens kick pulse generator that generates a lens kick pulse to be moved;
A track counter that counts the number of track crossings generated when the lens kick pulse is generated, and a storage unit that stores an address of a predetermined track at the normal track pitch and an address of a track at a different track pitch.
A comparison unit that compares the count values of the track counters at the two addresses, and a control unit that determines whether the optical disc is legitimate based on the comparison result of the comparison unit. An optical disc playback device. 3. A reproducing apparatus for an optical disk as defined in claim 1, wherein the optical disk irradiates a laser beam on the optical disk to read out information, and a tracking error detecting unit generates a tracking error signal based on the information of the pickup unit. A tracking processing unit that drives and controls a driver of the pickup unit based on the tracking error signal; and a lens kick pulse that moves a lens of the pickup unit in the radial direction of the optical disc by the same distance as a normal track pitch. A generator,
An address recognizing unit for recognizing an address from information read from the pickup unit, a storage unit for storing addresses of tracks having different track pitches, and continuity for verifying continuity of addresses before and after a lens kick is performed An optical disc reproducing apparatus comprising: a verification unit; and a control unit that determines whether the optical disc is legitimate based on the verification result of the verification unit. 4. A reproducing apparatus for an optical disk according to claim 1, wherein the optical disk irradiates a laser beam to the optical disk to read information, an address recognizing unit for recognizing an address based on the information of the pickup unit, A storage unit for storing addresses immediately before and after the track having the different track pitch, a measuring unit for measuring a rotation cycle of the optical disc in the portion having the different track pitch, and a rotation cycle measured by the measurement unit An optical disc reproducing apparatus, comprising: a comparing section for comparing the optical disc based on a predetermined formula; and a control section for judging whether or not the optical disc is legitimate based on a comparison result of the comparing section.