JP2002237054A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk which makes the constitution of a demodulating circuit simple. SOLUTION: The optical disk which has tracks is provided with wobble parts which zigzag and non-wobble parts which do not zigzag on the tracks and 1st subordinate information and 2nd subordinate information as data other than user data are superimposed and stored on the track by using combinations of the wobble parts and non-wobble parts; and for the 1st subordinate information, at least the length of the wobble parts or non-wobble parts is made different according to whether bits has a logical value '0' or '1' and for the 2nd subordinate information, the phase of the zigzagging of the bits at the wobble parts is made different from the phase of the zigzagging of the last bits at the wobble parts only when the bits have the logical value '1'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a physical format of a rewritable optical disk using a phase change medium or a magneto-optical (MO) medium, or a write-once (write-once) optical disk using a dye-based medium. In particular, the present invention relates to a physical format suitable for handling a large amount of data such as image data and audio data.

[0002]

2. Description of the Related Art DVDs (digital video disks), MO disks, and CDs (compact disks) have been commercialized as large-capacity storage media used in computers. Also, with the spread of computers, users often edit data stored in a storage medium, and the need for a storage medium on which data can be changed or additionally recorded has been increased.

A rewritable storage medium on which a user can change data many times is a DVD-RAM (randomly readable and writable memory) using a phase change medium, an MO disk using an MO medium, CD-RW (Re
Writable). A write-once (write-once) storage medium on which a user can write data only once is a CD-R using a dye-based medium. In these storage media, addresses for recognizing the positions where the data are written on these storage media are stored in advance.

On the DVD-RAM or MO disk, an ID section (Identification section) for indicating an address is provided separately from a section in which user data is stored.

[0005] For address management in the above-mentioned CD-RW and CD-R, a wobble addressing method based on FM modulation (frequency modulation) is used. Here, wobble means meandering, and indicates a structure in which tracks on the disk meander in the radial direction of the disk. That is, in a CD-RW or CD-R, an address is stored by changing the frequency of a wobble (meandering) of a track. Therefore, CD-RW and C
In the DR, user data and addresses are superimposed and stored along the track.

FIG. 11 is a diagram showing the structure of a wobble track formed on a conventional optical disk. On this optical disk, two types of sub-information, that is, first sub-information and second sub-information, are recorded so as to be superimposed on one track.

[0007] The two types of sub-information are modulated by mutually different methods. That is, the first sub-information is amplitude-modulated as shown in (1) in the figure. In particular,
The bit “0” constituting the first sub information includes a wobble part and a non-wobble part, and the bit “1” includes only the wobble part.

The second sub-information is phase-modulated as shown in (2) in the figure. Specifically, the wobble phase differs by 180 degrees between bit “0” and bit “1” that constitute the second sub information.

A composite of the first sub-information and the second sub-information is a waveform shown in (3) in the figure, and this waveform is a wobble track waveform of the optical disk. Therefore, two types of sub-information are recorded on this wobble track in a superimposed manner.

[0010]

However, the above prior art has a problem that a complicated demodulation circuit is required to demodulate the second sub information.

FIG. 12 is a block diagram showing a configuration of a demodulation circuit for demodulating the second sub-information in the above-mentioned conventional technology. The wobble signal, which is an input signal to the demodulation circuit, is input to the multiplier 12 via the band pass filter 11. The output of the local oscillator 13 is also input to the multiplier 12. The output of the multiplier 12 is input to a positive / negative determiner 15 via a low-pass filter 14. The positive / negative determiner 15 outputs a demodulation result.

That is, in the prior art, since it is necessary to perform synchronous detection, a local oscillator 13 for outputting a signal whose frequency and phase are synchronized with a wobble signal which is an input signal to the demodulation circuit is provided in the demodulation circuit. Required, which complicates the demodulation circuit.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide an optical disk having a simple structure of a demodulation circuit.

[0014]

According to a first aspect of the present invention, there is provided a rewritable optical disk such as a phase change medium or a magneto-optical medium or a write-once type optical disk such as a dye-based medium having a track for recording user data. In the optical disc, the track is provided with a wobble portion meandering in a radial direction of the optical disc and a non-wobble portion that does not meander, and the user is provided by using a combination of the wobble portion and the non-wobble portion. First sub-information and second sub-information, which are data other than data, are superimposed and stored on the track, and the first sub-information has at least one of a length of a wobble portion and a non-wobble portion. Is different between a case where the bit has a logical value “0” and a case where the bit has a logical value “1”. Only when taking "1", an optical disc, characterized in that the phase of the meander in the wobble of the bit, is changed with respect to the meandering of the phase of the wobble of the immediately preceding bit.

According to a second aspect of the present invention, in the first sub-information, a non-wobble portion exists when a bit takes one of a logical value “0” and “1”, and the bit is logical. 2. A non-wobble portion does not exist when the other of the values "0" and "1" is taken.
4. The optical disc according to 1.

According to a third aspect of the present invention, in the optical disc according to the first or second aspect, the length of the non-wobble portion is an integral multiple of one meandering period in the wobble portion. is there.

According to a fourth aspect of the present invention, the length of the wobble portion and the non-wobble portion is an integral multiple of one meandering period in the wobble portion. Optical disk.

According to a fifth aspect of the present invention, in the second sub information, the amount of change in the meandering phase of the wobble portion is 180.
The optical disk according to claim 1, wherein the optical disk is set to be close to the optical disk.

According to a sixth aspect of the present invention, at least one of the first sub-information and the second sub-information is an address in the track. 4. The optical disc according to 1.

[0020]

FIG. 1 is a diagram showing a configuration common to optical disks in each embodiment of the present invention described below. Tracks are provided on the surface of the optical disk P1, and sub-information is recorded in advance along the tracks. User data is superimposed and recorded on the track on which the sub information is recorded. Here, the sub-information is information other than the user data, and a typical example is an address. Also, various parameter information related to the disc is included in the sub information.

The optical disc P1 is, for example, a rewritable optical disc such as a DVD-RAM or CD-RW using a phase change medium, an MO disc using an MO medium, or a write-once such as a CD-R using a dye-based medium. Type optical disc.

As shown in the figure, a wobble track WT1 is provided on the surface of the optical disk P1, and user data is recorded along the wobble track WT1. Here, the wobble means a meandering, and indicates a structure in which the track is meandering in the radial direction of the optical disc P1. However, this wobble track WT1 has a wobble portion AWT and a non-wobble non-wobble portion NWT as shown in the figure. These wobble parts AWT
And the non-wobble portion NWT, the above-described sub-information is recorded on the track.

FIG. 2 is an enlarged view showing a detailed structure of the wobble track WT1 on the optical disk P1. A meandering track groove T is provided on the surface of the optical disk P1, and the bottom of the track groove T is called a groove G, and a portion sandwiched between adjacent track grooves T is called a land L.
The undulation (meandering) of the track groove T is called a wobble.

When recording user data on the optical disk P1 using the land & groove recording method,
Recording marks P are formed on both the land L and the groove G. In order to read recorded data, light H is incident from the bottom surface of the optical disc P1.

The wobble of the track groove T is
1 is used to represent sub-information of user data recorded in 1. The sub information is, for example, information indicating a position of user data recorded along the track groove T, that is, an address. Therefore, on the optical disk P1, the user data and the sub information are recorded in a superimposed manner along the track groove T.

FIG. 3 is a diagram showing the structure of a wobble track formed on an optical disc in the first embodiment of the present invention. On the optical disc in the present embodiment, two types of sub-information, that is, first sub-information and second sub-information, are recorded so as to be superimposed on one track.

The two types of sub-information are modulated by mutually different methods. That is, the first sub-information is amplitude-modulated as shown in (1) in the figure. In particular,
The bit “0” constituting the first sub information includes a wobble part and a non-wobble part, and the bit “1” includes only the wobble part. That is, the amplitude modulation here is a digital modulation, and the digital modulation is more advantageous than the analog modulation in securing reliability in an optical disk system having much noise. Note that it is of course possible to adopt a configuration in which the combination opposite to the above, that is, the bit “0” includes only the wobble portion, and the bit “1” includes the wobble portion and the non-wobble portion.

The second sub-information is phase-modulated as shown in (2) in the figure. Specifically, only when the bit constituting the second sub information is “1”, the phase is shifted by 180 degrees with respect to the wobble waveform of the immediately preceding bit. When the bit forming the second sub information is "0", no phase shift is performed.

By shifting the phase by 180 degrees, reliability is ensured in an optical disk system having a lot of noise. Further, bit “0” to bit “1”
At the transition point from the bit "1" to the transition point from the bit "1" to the bit "0", the wobble waveform returns to the center of the amplitude. With such a configuration, the manufacture of the optical disk is facilitated.

The composite of the first sub-information and the second sub-information is the waveform shown in (3) in the figure, and this waveform is the waveform of the wobble track of the optical disk. Therefore, two types of sub-information are recorded on this wobble track in a superimposed manner.

FIG. 4 is a diagram showing bits in the first sub-information and an amplitude-modulated waveform corresponding to the bits. In (Example 1) in the figure, bit “0” corresponds to a waveform including a wobble portion and a non-wobble portion,
Bit "1" corresponds to a waveform including only the wobble portion. Conversely, in (Example 2) in the figure, the bit “0”
Corresponds to a waveform including only the wobble portion, and bit “1” corresponds to a waveform including the wobble portion and the non-wobble portion. In these waveforms, the length (period) of the non-wobble portion is set to an integral multiple of the wobble cycle in the wobble portion. By setting in this way, the manufacture of the optical disk is facilitated, and the PLL control system in the wobble reading device can be operated stably. It goes without saying that a method other than the above may be used as the amplitude modulation method.

FIG. 5 is a diagram showing a structure of a wobble track formed on an optical disc in the second embodiment of the present invention. Also on the optical disc in this embodiment, two types of sub-information, that is, first sub-information and second sub-information, are recorded so as to be superimposed on one track. However, the first sub-information recorded on the track in the present embodiment is converted sub-information obtained by converting the original sub-information according to a predetermined conversion rule. The conversion sub-information and conversion rules will be described later.

The two types of sub-information are modulated by mutually different methods. That is, the first sub information is subjected to the improved AM modulation as shown in (1) in the figure. This improved AM modulation will be described later.

The second sub-information is phase-modulated as shown in (2) in the figure. This phase modulation is the same as the phase modulation in the first embodiment.

The composite of the first sub-information and the second sub-information is the waveform shown in (3) in the figure, and this waveform is the waveform of the wobble track of the optical disk. Therefore, two types of sub-information are recorded on this wobble track in a superimposed manner.

The conversion sub-information will be described. FIG.
Records sub-information on a wobble of a track, that is, writes a wobble / record on an optical disk based on sub-information data.
3 shows a procedure for forming a track. First, the first sub information data is converted into the first converted sub information data by the conversion table. Next, the first converted sub-information data is subjected to the improved AM modulation, and the improved AM-modulated waveform is combined with the phase-modulated waveform as the second sub-information. The wobble of the truck.

Next, the conversion rule will be described. FIG.
FIG. 4 is a diagram illustrating an example of the conversion rule, that is, a conversion table. As described above, the conversion table receives the first sub-information data and outputs the first converted sub-information data. Both the first sub information data and the first converted sub information data are digital data composed of bit “0” and bit “1”. According to the illustrated conversion table, 2
The first sub information data composed of bits is converted into the first converted sub information data composed of 4 bits. First
In any case, the conversion sub-information data includes the same number of bits “0” and bits “1”. That is, of the first conversion sub-information data composed of 4 bits, 2 bits are “
0 ", and the remaining two bits are" 1 ".

The improved AM modulation will be described. FIG. 8 is a diagram showing an example of a waveform generated by the improved AM modulation. With this improved AM modulation, the first
The bit "0" included in the converted sub-information data is converted into the waveform shown in FIG. 7A, and the bit "1" included in the first converted sub-information data is converted into the waveform shown in FIG. It is converted to the waveform shown.

The waveform corresponding to the bit "0" shown in FIG. 7A has a wobble period A0 having a meandering period of 10 periods.
And a non-wobble period B0 that does not meander. The length of the non-wobble period B0 is set to the length of two meandering periods in the wobble period A0. In addition,
The meandering period Td in the wobble period A0 is always constant.

The waveform corresponding to the bit "1" shown in FIG. 4B is a wobble period A1 having a meandering period of 14 periods.
And a non-wobbled non-wobble period B1. The length of the non-wobble period B1 is set to the length of two meandering periods in the wobble period A1. In addition,
The meandering period in the wobble period A1 is always constant and equal to the meandering period Td in the wobble period A0 included in the waveform corresponding to the bit “0”. Therefore, the length of the non-wobble period B1 included in the waveform corresponding to the bit “1” is equal to the length of the non-wobble period B0 included in the waveform corresponding to the bit “0”.

If the lengths of the above A0, B0, A1, and B1 are expressed in units of a common meandering period Td, the following is obtained. (A0, B0) = (10, 2) (A1, B1) = (14, 2) That is, bit “0” and bit “1” are distinguished by the length of the section where the wobble is continuous. There is no need to change the wobble frequency.

The length of the wobble periods A0 and A1 is not limited to 10 or 14 periods, but can be set arbitrarily.

In the above example, the length of the non-wobble period B0 included in the bit “0” is equal to the length of the non-wobble period B1 included in the bit “1”. That is, B0 = B1 = length of two periods of wobble. Therefore, the bit is “0” or “1”
Therefore, it is not necessary to change the length of the non-wobble period, so that the optical disk can be realized more easily.

The length of the non-wobble periods B0 and B1 is about one or two periods of the wobble in consideration of the influence on the PLL circuit for synchronizing the wobble for reading the wobble. It is appropriate to do. However, this length may be determined according to the system to which the present invention is applied, and the present invention is not limited to this length being about one or two periods of the wobble. Absent.

According to the conversion table and the waveform, all the first conversion sub-information data have the same length on the track. That is, the bit “0” and the bit “1” constituting the first converted sub-information data have different lengths of waveforms representing the respective bits, and accordingly have different lengths on the track. However, the first converted sub-information data is always a set of 4 bits and includes the same number of bits "0" and bits "1". The same applies to the first conversion sub-information data of the value. Therefore, the lengths of the first converted sub-information data on the track can be made uniform, and the data writing control can be simplified.

In the above example, the length of the non-wobble period B0 included in the bit "0" in the first converted sub-information data and the bit "1" in the first converted sub-information data are included. The length of the non-wobble period B1 is equal to the length of the non-wobble period.
Even if the difference in the length of the non-wobble period is used for bit identification, the length of the first converted sub-information data for 4 bits remains unchanged.

FIG. 9 is a diagram showing an example of conversion from the first sub information data to the first converted sub information data. As shown, if the first sub-information data is composed of 8 bits, the first converted sub-information data obtained by converting the first sub-information data using the conversion table has 16 bits, and Of these, 8 bits are "0" and the remaining 8 bits are "1".

More specifically, in <Example 1> in the figure, the first sub information data (01111111) is converted into the first converted sub information data (110111) by the conversion table shown in FIG.
0101010101010). That is, the first two bits (01) of the first sub information data are
The conversion table shown in FIG. 7 is converted into 4-bit first conversion sub-information data (1100), and the subsequent 2-bit first sub-information data (11) is converted into 4-bit first sub-information data (11). Is converted to the conversion sub-information data (1010).

When the total length of the bit string of the first converted sub information data is expressed in units of a wobble period Td, the total length = the length of “0” + the length of “1” = 8 bits × (10Td + 2Td) +8 bits × (14Td + 2Td) = 224Td.

In <Example 2> in the figure, the first sub-information data (10000000) is converted into the first sub-information data (001101010) by the conversion table shown in FIG.
1010101). That is, the first two bits (10) of the first sub information data are the first four bits of the first sub information data.
, And the subsequent 2-bit first sub-information data (00) is converted into 4-bit first converted sub-information data (0101).

When the entire length of the bit string of the first converted sub information data is expressed in units of a wobble period Td, the total length = the length of “0” + the length of “1” = 8 bits × (10Td + 2Td) +8 bits × (14Td + 2Td) = 224Td, which is the same length as in <Example 1>.

That is, the length of recording the first sub information having a fixed number of bits on the track is always constant, which facilitates the manufacture of the optical disc.

As in the above example, A0, B0, A
If all of the values 1 and B1 are set to integral multiples of the wobble period Td, the manufacture of the optical disk is facilitated, and the PLL control system in the wobble reading device can be operated stably.

FIG. 10 is a block diagram showing a configuration of a demodulation circuit for demodulating the second sub information recorded on the optical disc of the present invention. The wobble signal, which is an input signal to the demodulation circuit, is input to the multiplier 2 via the band-pass filter 1 and also to the delay unit 3. Delay device 3
Delays the input signal. The amount of delay is, for example, one cycle of the wobble waveform.

The output of the delay unit 3 is input to the multiplier 2. That is, the multiplier 2 multiplies the output of the band-pass filter 1 by the output of the delay unit 3. As a result, immediately after the bit switching, the current waveform is multiplied by the waveform one bit before, and if the current waveform and the waveform one bit before are in phase, a positive signal is output, and the current waveform is 1
If the waveform before the bit has an opposite phase (a phase different by 180 degrees), a negative signal is output. That is, when the bit is "1"
A negative signal is output only immediately after switching to.

The output of the multiplier 2 is input to a positive / negative determiner 5 via a low-pass filter 4. The positive / negative determiner 5 outputs a demodulation result.

That is, in the optical disk of the present invention, since the delay detection can be adopted, there is no need to generate a signal synchronized with the wobble signal in the demodulation circuit, and the configuration of the demodulation circuit is simplified.

[0058]

According to the present invention, two types of sub-information can be superimposed and recorded on one track, so that more sub-information can be recorded on an optical disk than before, and The configuration of the demodulation circuit for demodulating the sub information is simplified. Therefore, it is possible to provide an optical disk format suitable for increasing the capacity.

In the first sub-information, when the bit takes one of the logical values “0” and “1”, a non-wobble portion exists, and the bit has the logical value “0” or “1”.
In the case where either one of 1 ”is adopted, if there is no non-wobble portion, the amplitude information can be superimposed on the track with a simple configuration.

If the length of the non-wobble portion is set to an integral multiple of one meandering period in the wobble portion, the amplitude information can be superimposed on the track with a simple configuration, and the optical disk can be easily manufactured. Become.

Further, if the length of the wobble portion and the non-wobble portion is set to an integral multiple of one meandering cycle in the wobble portion, amplitude information can be superimposed on the track with a simple configuration. Becomes easier.

Further, if the amount of change in the meandering phase of the wobble portion in the second sub-information is approximately 180 degrees, the phase information can be superimposed on the track with a simple configuration, and the optical disk can be easily manufactured. become.

Further, at least the first sub-information or the second sub-information
If any one of the sub-information is an address in a track, it is not necessary to provide an area for indicating the address information in the disk format, so that a highly efficient optical disk format can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration common to optical disks in each embodiment of the present invention.

FIG. 2 is an enlarged view showing a detailed configuration of a wobble track on an optical disc.

FIG. 3 is a diagram showing a configuration of a wobble track formed on an optical disc in the first embodiment of the present invention.

FIG. 4 is a diagram showing bits in the first sub-information and an amplitude-modulated waveform corresponding to the bits.

FIG. 5 is a diagram showing a configuration of a wobble track formed on an optical disc in a second embodiment of the present invention.

FIG. 6 is a diagram showing a procedure for recording sub-information on a wobble of a track.

FIG. 7 is a diagram illustrating an example of a conversion table.

FIG. 8 is a diagram illustrating an example of a waveform generated by the improved AM modulation.

FIG. 9 is a diagram showing an example of conversion from first sub information data to first converted sub information data.

FIG. 10 is a block diagram showing a configuration of a demodulation circuit for demodulating second sub information recorded on the optical disc of the present invention.

FIG. 11 is a diagram showing a configuration of a wobble track formed on a conventional optical disc.

FIG. 12 is a block diagram showing a configuration of a demodulation circuit for demodulating second sub-information according to the related art.

[Explanation of symbols]

P1 optical disk WT1 wobble track (track) AWT wobble part NWT non-wobble part T track groove L land G groove P recording mark H light 1,11 bandpass filter 2,12 multiplier 3 delay unit 13 local oscillator 4,14 low-pass filter 5, 15 Positive / negative judgment device

Claims (6)

[Claims] 1. A rewritable optical disk such as a phase-change medium or a magneto-optical medium or a write-once optical disk such as a dye-based medium having a track for recording user data, wherein the track has a radial direction of the optical disk. And a non-wobble portion that does not meander is provided. Using a combination of the wobble portion and the non-wobble portion, the first sub-information and the 2 is superimposed on the track and stored, and in the first sub-information, at least one of the length of the wobble part and the non-wobble part is equal to the case where the bit takes a logical value “0”. , The bit takes a logical value “1”. In the second sub-information, this bit is set only when the bit takes a logical value “1”. Optical disc, characterized in that the meandering of the phase at the wobble section, is changed with respect to the meandering of the phase of the wobble of the immediately preceding bit. 2. In the first sub-information, a non-wobble portion exists when a bit takes one of a logical value “0” and “1”, and the bit has a logical value “0” or “1”.
2. The optical disk according to claim 1, wherein a non-wobble portion does not exist when any one of 1 "is taken. 3. The optical disk according to claim 1, wherein the length of the non-wobble portion is an integral multiple of one cycle of meandering in the wobble portion. 4. The optical disk according to claim 1, wherein the lengths of the wobble portion and the non-wobble portion are set to integral multiples of one meandering period in the wobble portion. 5. The optical disc according to claim 1, wherein the amount of change in the meandering phase of the wobble portion in the second sub-information is approximately 180 degrees. 6. At least the first sub-information or the second sub-information
6. The optical disk according to claim 1, wherein one of the sub-information is an address in the track.