JP3901150B2 - Optical disc, information reproducing method and recording method - Google Patents

Description

  The present invention relates to a recording format of a large-capacity recording type optical disc, recording area identification information of an optical disc having a groove or land portion as a recording track, that is, a method for arranging / holding addresses.

An example of the track structure of a conventional optical disc will be described with reference to FIG. A plurality of groove tracks 11 and land tracks 12 are alternately arranged in the radial direction of the disk-shaped recording medium. Each track is wobbled by a minute amount in the radial direction. Each track is divided into a plurality of arcuate sectors aligned in the radial direction, and a header 6 having address information for identifying a recording area is disposed at the head of each arcuate sector. The headers 6 are arranged in the radial direction, that is, on the radiation. In this example, the width of each track is about 0.6 μm, and the groove depth of the groove is about 60 nm. In this example, the sector length is about 6 mm, which corresponds to a user capacity of 2048 bytes. The groove part and the land part are wobbled in the radial direction with an amplitude of about 20 nm. The wobble cycle is set to 1/232 of the sector length, that is, about 25 μm. The ratio of 1: 232 is selected so that the wobble period is an integral multiple of the length of recording data (channel bit length). This is because the recording clock can be easily generated from the wobble.
FIG. 16 shows details of the header portion at the head of the track, that is, the identification information portion. In FIG. 16, the identification information is radially arranged at two locations of the first position 631 and the second position 632 along the radial direction. The front and rear tracks are connected by the grooves 11 and the lands 12. In the example of this figure, each identification information corresponds to the recording area of the information track on the right side. Further, identification information corresponding to the groove information track 3 on the right side of the drawing is arranged at the first position 631, and identification information corresponding to the inter-groove information track 4 is arranged at the second position 632. That is, the identification information is arranged so that the positions in the direction along the information track are different between adjacent tracks and coincide with two adjacent tracks. That is, when viewed on the boundary line between the land and the groove track, the arrangement position of the identification information is divided into the first and second areas,
The first and second identification information areas are alternately used every other track.
For this reason, for example, when the light spot 21 scans on the groove portion 11, only one of the pits is always reproduced, and there is no fear of crosstalk from adjacent tracks. Therefore, it becomes possible to reproduce the address information arranged in the prepits satisfactorily without crosstalk. In this example, prepit address information is recorded by an 8/16 modulation code (channel bit length 0.14 μm).
The header identification information is formed by small pits. This is formed at the same time as the groove or the like as the irregularities of the substrate during the manufacture of the disk.

A phase change recording film (GeSbTe) is used as the recording film, and the recording mark is formed in the form of an amorphous region.
The above conventional example is described in detail in, for example, Japanese Patent No. 2856390.

  However, in the above conventional example, for example, in high-density recording in which recording / reproduction is performed using a blue light source, there is a problem that it is difficult to form fine embossed pits in the header portion. Further, since the header portion has no groove and cannot be used as a recording area, there is a problem that the use efficiency (format efficiency) of the recording track is lowered, which is disadvantageous for realizing a large capacity.

  As another conventional example in which address information is recorded by wobble in the groove portion without recording in the header portion, for example, there is a method described in the international standard ISO / IEC16969.

In this example, a frequency-modulated wobble groove is used to record address data. The disk is composed of about 3000 wobbles, and one bit of address data uses 7.5 cycles of wobble. When representing bit 1, among the 7.5 cycles, the first half is 4 cycles and the second half is 3.5 cycles. That is, the first half is a high frequency and the second half is a low frequency. The frequency ratio is 8
: 7. The reverse of bit 0 is represented by a low frequency wobble with 3.5 periods in the first half and a high frequency wobble with 4 periods in the second half. An address code word is composed of 48 address bits. Of the 48 bits of the address codeword, 14 bits are parity for error detection, and the first 4 bits are synchronization information for synchronizing with this codeword. The breakdown of these 4 bits, that is, 30 cycles of wobbles is 12 cycles of high frequency wobble, 3.5 cycles of low frequency wobble, 4 cycles of high frequency wobble, and 10.5 cycles of low frequency. At the boundary of normal address bits, the same frequency can be continuous only at most 8 periods of high frequency wobbles or 7 periods of low frequency wobbles. The synchronization information can be distinguished from other data by using it.

  However, in the above conventional example, one address bit of the address data is represented by 7.5 cycles of wobble, and the difference in frequency between the first half and the second half is not so large. It was difficult to detect the boundary of the part with high accuracy in units of wobble period. Further, since the difference between the synchronization information and other address bits is not so large, there is a problem that the false detection of the synchronization information is highly established. Further, the parity in the address code word is 14 bits at most, and since it has substantially no error correction function and only a check function, address information with false detection cannot be reproduced even with 1 bit in the address code word. In order to ensure the reliability of address reproduction, it is necessary to ensure a sufficient S / N of the medium. In particular, if this method is applied to a high-density disk using a blue light source, the efficiency of the detector with the blue light source is low, so that it is difficult to ensure a sufficient S / N.

  A first object of the present invention is to provide a high-performance optical disk that can be easily synchronized with an address signal, that is, can reproduce the address signal at high speed, in a wobble address system having an advantageous format efficiency. .

  A second object of the present invention is to provide an optical disc on which address information that can be detected with high reliability is arranged.

  A third object of the present invention is to provide a method for providing necessary medium information to a recordable optical disk without using embossed pits that are difficult to form.

In order to achieve the object of the present invention, the following means were used.
(1) An optical disc having at least one of spiral or concentric grooves or inter-grooves as an information recording area, and an unmodulated synchronization component at least at a constant frequency and a signal component modulated according to at least address data The groove portion or the inter-groove portion is formed with a slight displacement in the radial direction.

The minute displacement of the groove, that is, the groove, or the groove, that is, the land, is usually called a wobble. The wobble waveform is a tracking signal detector (for example, a push-pull detector) for tracking the track. Therefore, it can be easily detected. If the method of the present means is used, the detected wobble signal includes both an unmodulated component and a modulated component. Using this unmodulated component, it is possible to easily perform speed control and phase synchronization to information, and it is easy to reproduce address information using the modulated component.

On this occasion,
(2) The frequency band of the modulation component is not overlapped with the frequency band of the non-modulation component.

For example, a waveform obtained by superimposing a 180 degree phase modulated second harmonic on an unmodulated fundamental wave is used.

As a result, it is possible to easily separate the non-modulated component and the address information by separating the frequency by a band-pass filter or the like and reliably detect it. That is, the first object of the present invention is achieved.
(3) The unmodulated component and the address information may be synthesized in a time-division manner with a period equal to or more than one-half of the average period of wobbles and approximately at an equal period.

  For example, the unmodulated component is divided into the wobble front edge and the modulated component is divided into the rear edge. As a result, stable synchronization is performed using a PLL circuit or the like that selectively detects only the front edge, and address information can be obtained by detecting the position of the rear edge.

  As another example, a set of three edges may be used, and one of the three edges may be unmodulated, and the remaining two edges may be a phase-modulated waveform. As yet another example, the degree of modulation may be periodically changed from the non-modulating part to the modulating part.

In any case, the phase synchronization information can be obtained stably by extracting the unmodulated signal component regardless of the address information, so that high-speed synchronization at the time of access is possible. That is, the first object of the present invention is achieved.
(4) An optical disc having at least one of a spiral or concentric groove portion or an inter-groove portion as an information recording region, wherein at least one of the groove portion or the inter-groove portion is formed by wobbling in a radial direction, A plurality of types of unit wobble waveforms of a fixed length are associated with at least binary information, and a plurality of unit wobble waveforms are arranged side by side, and a 1-bit address is provided by at least two types of wobble sequences that are arranged differently. Data or user data was expressed.

That is, as a plurality of types of wobble waveforms, for example, one as shown in FIG. 1A is used to represent one bit of address data having a wobble string in which a plurality of these waveforms are arranged. In this case, it is preferable that the plurality of types of wobble trains have as many different portions as possible (make them different from each other in a plurality of unit wobble waveforms). This is because if there are many differences between wobble sequences, even if some unit wobbles cannot be detected normally due to an error such as a defect, the wobble sequence that is closest to the reproduced wobble sequence is determined. By examining it, it can be set as reproduction address data. The greater the difference between the wobble sequences, the more desirable because it can tolerate many false positive wobbles. In addition, the longer the wobble string (the greater the number of unit wobble waveforms included in the wobble string), the higher the resistance to false detection. That is, the second object of the present invention is achieved.
(5) The wobble train is arranged in such a way that the autocorrelation is strong with respect to the shift for each unit wobble waveform length.

  When auto-correlation is strong, comparing the wobble sequence and the wobble sequence that has been (cyclically) shifted by itself for each unit wobble waveform, of course, all unit wobbles match when there is no shift. In some cases, it means the property that the number of matches will be reduced to about half. For example, there is a wobble sequence obtained by associating different unit wobble waveforms with 0 and 1 of the longest periodic sequence (M sequence).

By using such a wobble sequence with strong autocorrelation,
It is possible to accurately synchronize with the playback signal with an accuracy less than the unit wobble waveform length. If the synchronization to the unit wobble waveform is established by PLL or the like, the synchronization of 1 bit unit of wobble data can be surely performed by the clock unit of PLL. That is, the first object of the present invention is achieved.

If multiple wobble sequences are used to represent address bits, the cross-correlation (including shift) between different wobble sequences should be as low as possible. That is, it is not desirable to select a wobble string that is likely to be mistaken for a different wobble string. Desirably, the cross-correlation is always selected to be 2/3 or less of the peak value obtained by autocorrelation.
(6) An optical disc having at least one of a spiral or concentric groove portion or an inter-groove portion as an information recording area, wherein at least one of the groove portion or the inter-groove portion is formed by wobbling in a radial direction, An address code word for identifying a recording area is composed of a plurality of wobbles, and a plurality of wobble strings for synchronization are arranged in the address code word.
Or (7) An optical disk having at least one of a spiral or concentric groove portion or an inter-groove portion as an information recording area, wherein at least one of the groove portion or the inter-groove portion is wobbled in the radial direction. The address code word for identifying the recording area is constituted by a plurality of wobbles, and the address code is divided and arranged into a plurality of synchronization frames delimited by a wobble string for synchronization.

  Thereby, all synchronization can be established in a time shorter than the time required for reproducing the address codeword itself. That is, the second object of the present invention is achieved.

  In addition, since a plurality of pieces of synchronization information are arranged in one code, redundancy can be added to the synchronization information itself, and as a result, reliability is ensured against missing synchronization information and false detection. Can do. In addition, high reliability can be ensured because information such as out-of-synchronization and out-of-track can be detected in a shorter time.

here,
(8) The above-described wobble sequence for synchronization is composed of a plurality of types of arrays, and within the address codeword, using the difference in the arrangement or arrangement of the plurality of types of wobble sequences arranged in the address codeword. It is preferable to arrange a plurality of types of wobble trains so that the positions of these can be specified.

That is, it is desirable that the synchronization information is arranged in a plurality of types instead of one, and the synchronization information is preferably arranged so as to be different depending on the position in the codeword. By doing so, one of the plurality of synchronization information in the codeword is selected. The synchronization to the entire codeword can be established by simply reproducing the part.
(9) An optical disc having at least one of a spiral or concentric groove portion or an inter-groove portion as an information recording area, wherein at least one of the groove portion or the inter-groove portion is wobbled in the radial direction, An address code word for identifying a recording area is constituted by a plurality of wobbles, and additional data other than address information is arranged in the address code word, and the additional data arranged in the plurality of address code words are grouped together. A code block for error correction of additional data was constructed.

Accordingly, the medium information necessary for the recordable optical disk can be provided without using the embossed pits that are difficult to form, and the third object of the present invention can be achieved.
At this time, since the additional information is added with an error correction code, the necessary information can be reliably reproduced even on a medium having a defective portion.
(10) As the additional data, management information or encryption key information for protecting data or restricting access at the time of recording or reproduction is stored, or (11) as the additional data, the type of the disc And control information indicating features were stored.

  These are information that has been recorded using conventional embossed data, but can be provided without using the embossed data, so that an inexpensive disc can be provided.

    The optical disk of the present invention can be easily synchronized with the address signal, that is, can reproduce the address signal at high speed in the wobble address system having an advantageous format efficiency. In addition, the address information can be detected with high reliability by the efficient modulation method and redundancy of the address signal. This effect is particularly effective in optical recording and reproduction using a blue light source, which tends to reduce the signal light quantity and reproduction quality. In addition, since the wobble holds other additional data of the address information and the necessary medium information can be given to the recordable optical disk without using the embossed pits, a highly reliable (high security) disk can be obtained. It can be realized inexpensively and easily. The retention of the additional data by the wobble was realized for the first time by introducing the wobble with high detection efficiency of the present invention.

[Example 1]
FIG. 1C shows a partially enlarged view of the optical disk of one embodiment of the present invention. The information track is composed of a groove 11 provided in a spiral shape on a disk-shaped substrate. In this embodiment, no information is recorded in the land portion 12. The track spacing (average distance between adjacent groove centers) is 0.32 microns. The groove portion is a groove portion provided on the substrate, and the depth of the groove portion is about 20 nm. Since this embodiment assumes that recording / reproduction is performed with an optical head having a wavelength of about 405 nm and an aperture ratio of about 0.85, the groove depth of 20 nm is substantially equal to the optical distance of 1/12 of the wavelength. . The groove is formed by wobbling in the radial direction with an amplitude of about 15 nmpp. As for the wobble, a waveform as shown in FIG. 1B in which the four types of unit wobble waveforms shown in FIG. 1A are combined is recorded in the form of a wobble row as shown in FIG. As in (b)
When combining, the upper and lower waveforms in FIG. (A) are selected so that the phase of the waveform at the combining portion is continuous. For the sake of illustration, FIG. 3C shows the wobble period shortened and the wobble amplitude in the radial direction is emphasized (actually, the wobble amplitude is about 5% of the track width). Because it can not).

  The length of the unit wobble waveform in FIG. 1A is 72 channel bits of the recording data. Here, in this embodiment, the bit length of the user recording data is about 0.11 μm, and since the RLL (1, 7) code is used, the channel bit length is 0.073 μm. That is, the length of the unit wobble waveform is about 5.2 μm.

  The unit wobble waveform is composed of a high frequency component of one cycle and a low frequency component of a half cycle, and the frequency of the high frequency component and the low frequency component is a ratio of 2: 1. The feature of the wobble of this embodiment is that the unit wobble waveform is always composed of a wobble waveform of 1.5 periods. Therefore, a carrier wave having a unit wobble waveform length of 1.5 periods can be easily reproduced.

  FIG. 6 is a table showing the correspondence between the wobble string and the address data and the synchronization code. In the figure, 1 and 0 correspond to the waveform 1 and the waveform 0 in FIG. The synchronization code A is a 31-bit longest periodic sequence (M sequence) generated by a 5-bit shift register, and the synchronization code B is a complement sequence of the synchronization code A. Data 0 is another M sequence having a length of 31 bits, and data 1 is its complement sequence.

These four types of autocorrelation functions and cross-correlation functions are shown in FIG. When obtaining this correlation function, the sum of the sequence length is taken as 1 when the corresponding bits of the two types of sequences match and -1 when they do not match. The shifts are 0 and 31, and the autocorrelation function is 31, and the other points and the cross-correlation function are 11 or less. Since correlation function = (number of matches) − (number of mismatches), to say that the correlation function is 11 or less means that the number of matches is 21 or less and the number of mismatches is 10 or more. Therefore, there must be at least 10 unit wobble mismatch in all other cases compared to the case where you match yourself. Using this fact, it is easy to synchronize in units of 31 bits. In order to achieve synchronization, for example, using the circuit shown in FIG. 12 (described later), the correlation is checked, and the correlation function for each unit wobble shift is checked. You should do it. Since the correlation function is 31 at the maximum, (31−27) / 2 = a mismatch of up to 2 bits is allowed in synchronization. This example shows that address bit synchronization can be established even if 2 out of 31 unit wobbles cannot be detected normally. On the other hand, in order to erroneously determine that synchronization is established when synchronization is not possible, it is limited to cases where errors of at least (27-11) / 2 = 8 bits or more occur simultaneously. For example, if the unit wobble detection error probability is 1% (in fact, the detection error probability is 0.1
The probability that 31 is not obtained as a correlation function value is about 27%, but the probability that an error is 2 bits or more is about 0.3%, which is low in each stage. The probability of erroneously determining that synchronization is established is even lower, such as 10 minus 4 or less, and is at a level that causes no problem in practice.

  An address code word (address word) is configured by arranging the address data bits and the synchronization codes A and B having the 31 unit wobble waveforms as described above as shown in FIG. FIG. 8 shows three address words. Each address word is composed of four synchronization frames each having a length corresponding to 26 address bits. The arrows in the figure indicate the order of arrangement on the recording medium. Each synchronization frame has the synchronization codes A and B shown in FIG. 6 at the head (first bit) and the third bit, respectively, and the synchronization frame identification numbers at the second and fourth bits are the data 0 and data 1 shown in FIG. It is recorded using the code string. The remaining 22 bits are used as actual (address) data in this example. By such an arrangement of the synchronization code and the identification number, any one of the eight synchronization codes and any of the four identification numbers of the second bit and any of the four identification numbers of the fourth bit are detected. If so, the position in the address word is determined by the timing of their appearance. That is, synchronization is established for the address word. As described above, according to the present embodiment, the data for establishing synchronization (wobble train) has a sufficient redundancy, so that sufficient reliability can be obtained even in the system of the present embodiment using a blue light source in which S / N cannot be sufficiently secured. It is possible to establish synchronization at a degree.

In this embodiment, the synchronization codes A and B are arranged at the beginning of each synchronization frame. However, there is a method in which the synchronization code A is arranged at the beginning and the synchronization code B is distributed in the middle of the synchronization frame. In this case, there is a feature that a synchronization shift can be detected quickly even if a track is lost during recording / playback.

FIG. 9 shows the use of data in the address word.
As shown in FIG. 8, each address word is composed of four synchronization frames composed of a set of 4 bits for synchronization code and 22 bits for address data. The data that can be used for address information and the like is a total of 88 bits, that is, 11 bytes, including the four 22-bit portions. In the present embodiment, the first 4 bytes (32 bits) of these are used as address numbers, and 2 bytes (16 bits) are used as parity (check codes) for checking whether the address numbers are normally detected. This check code is added to only 4 bytes of the address number, and is a Reed-Solomon code in units of 8-bit symbols. The probability that an erroneous detection of an address number is missed by this check code is about 1 / 60,000, which is small enough for practical use. The additional data has 5 bytes for each address code word.

In this embodiment, the error correction block is configured as shown in FIG. 10 by combining additional data associated with a total of 64 address words. An error correction code of 5 × 12 = 60 bytes is added to 5 × 52 = 260 bytes of data, and it is possible to correct a burst error extending over a maximum of 6 address codes. The reliability of reproducing additional data is sufficiently secured.

In the above example, one address code word is 72 × 31 × 26 × 4 = 232128 channel bits of user data. Considering the format efficiency of about 85%, the user record data occupies a length of about 16 kB.
[Example 2]
An example of an optical recording / reproducing apparatus using the optical disk of Example 1 will be described with reference to FIG. FIG. 11 is a block diagram of an optical recording / reproducing apparatus using the optical recording format of the present invention. Light emitted from a laser light source 25 (wavelength of about 405 nm in this embodiment) that is a part of the head 2 is collimated into a substantially parallel light beam 22 through a collimator lens 24. The light beam 22 is irradiated onto the optical disk 11 through the objective lens 23 to form a spot 21, and then guided to the servo detector 26 and the signal detector 27 through the beam splitter 28 and the hologram element 29. Signals from each detector are added and subtracted to become servo signals such as tracking error signals and focus error signals, and are input to the servo circuit. The servo circuit controls the positions of the objective lens 31 and the entire optical head 2 based on the obtained tracking error signal and focus error signal, and positions the position of the light spot 21 in the target recording / reproducing area. The addition signal of the detector 27 is input to the signal reproduction block 41. The input signal is digitized after being filtered and frequency equalized by a signal processing circuit. Groove (groove) wobble information is detected as a differential signal from the division detector 27 and input to the wobble detection circuit 42 in the signal reproduction block 41. The wobble detection circuit 42 is synchronized with the wobble signal. Generates a clock and discriminates the wobble waveform.

An example of the internal configuration of the wobble signal detection circuit is shown in FIG.
The differential signal (push-pull signal) from the split detector 27 is first input to the band pass filter 421 and only the necessary band is extracted. The filtered signal is input to the binarization circuit 422 and binarized.
The binarized signal is input to the PLL circuit 425. The PLL circuit 425 includes a voltage controlled oscillator (VCO) 426, a carrier wave generation circuit (frequency division / multiplication circuit) 424, and a frequency phase comparator 423. In the example of this embodiment, the VCO 426 oscillates at the frequency of the channel clock and is divided by 72 ÷ 1.5 = 48 by the frequency dividing circuit 424 to generate a carrier wave. The phase and frequency of the carrier wave are compared with the binarized signal, and the rotation speed of the optical disk is controlled based on the comparison result. At the same time, the oscillation frequency of the VCO 426 is controlled. As a result, a carrier wave synchronized with the wobble signal is generated. .
Since the unit wobble waveform of FIG. 1 (all consisting of 1.5 cycles) has 72 channel clock cycles as described above, the average wobble cycle is 48 channel clocks. The unit wobble waveform is controlled to be 72 channel clocks by synchronizing with.

The reference wave generation circuit 429 uses a binary waveform of the upper left waveform in FIG. An exclusive OR operation is performed on the reference waveform and the binarized wobble signal, and the result is integrated for 72 channel bits by an integrator. If there is no noise, the settlement result is 72 in the upper left of FIG. 1A, 0 in the lower left, 36 in the upper right, and 36 in the lower right. Therefore, the discrimination circuit 428 can determine the waveform 1 when the integration result is 18 or more and 54 or less, and the waveform 0 in the other cases. This is so-called maximum likelihood detection that determines the most probable waveform, and is extremely reliable against noise.

Similar results can be obtained by treating binary data as 1 and −1 and multiplying them instead of the exclusive OR. In this case, since the integration result is 72, −72, 0, 0, similarly, −3 in the discrimination circuit 428.
6 to +36 may be regarded as waveform 1 and the others as waveform 0.

  The wobble waveform data detected as described above is processed by the address bit detection circuit 13 to determine the type of the wobble string, and is synchronized with the address bits to detect the address bits.

FIG. 12B shows the configuration of the address bit detection circuit. Outputs 0 and 1 from the wobble detection circuit are input to a 31-bit shift register, and are sequentially compared with the four types of patterns in FIG. Done. At this time, the pattern comparison for the 31-bit shift is nothing but the correlation function shown in FIG. Since any one of four patterns appears for every 31-bit data input, the correlation function has a pulse-like peak for every 31 bits. Therefore, the synchronization circuit makes a judgment based on a combination of a threshold value and an interval so as to determine “almost synchronous” when the correlation function exceeds a certain threshold (for example, 27) and “synchronize” when it exceeds 27 again after 31 bits. If installed, synchronization can be ensured. In addition, the threshold is relatively low before synchronization is confirmed, and instead, “continuity” processing, in which it is determined to be confirmed only after three or more consecutive synchronization pulses are detected, is emphasized. Synchronous performance and reliability can be further improved by setting a low threshold value and performing “switching” such as ignoring or increasing “window” processing such as ignoring or increasing the threshold value for pulses generated at intervals other than 31 bits. Improves.

Although there are four types of patterns, either A or B is detected reliably, and the place where synchronization to the synchronization frame (FIG. 8) is confirmed can be distinguished from the synchronization code or data depending on the address bit position. Data 0 and data 1 are completely inverted (complement), and the distance between patterns (Hamming distance) is 31 bits. For this reason, since it is possible to make a soft decision, that is, a majority decision, using only whether the determination is data 1 or data 0, establishment of erroneous detection of address bits can be significantly reduced. If the error detection rate of the unit wobble waveform is 1%, the error detection rate of the address bit is 10 minus 50 or less. As an extreme example, the error detection rate of the unit wobble waveform is 5%, which is the worst state. Even in this case, the false detection rate of the address bits is about 10 to the power of minus 14, so that high reliability sufficient for practical use can be secured.

The detected address bits are subjected to address data decoding processing such as error determination in the decoding circuit 46, and further, error correction processing and determination processing are performed on the additional data.

In some cases, error correction processing for additional data may be performed by a microprocessor.
[Example 3]
Another embodiment of the present invention is shown in FIG.

The unit wobble waveform is different from that of the first embodiment. In the first embodiment, the unit wobble waveform is composed of a high frequency component of one cycle and a low frequency component of a half cycle. In this embodiment, the unit wobble waveform is composed of a low frequency component of a half cycle and a high frequency component of a half cycle. Yes. In this example, as in the first embodiment, the frequency of the high frequency component and the low frequency component is 2: 1. The feature of the wobble of this embodiment is that the front edge is always located at the front end and the rear end of the unit wobble waveform and does not change at all regardless of the phase (position) address data of the front edge. Therefore, the wobble period per unit wobble waveform is one period regardless of the recording waveform. For the waveform reproduction of the present invention, for example, the method for confirming the presence / absence of an edge shown in FIG. Using the values obtained by
)

In the case of the method shown in FIG. 3, a recording / reproducing clock is generated so that the length of the unit wobble waveform is 3 periods, and binarized data is detected at intervals of the clock. In FIG. 3, the binarized data is reproduced in units of 3 channel bits as 100 → 0, 110 → 1.

The method of FIG. 4 is almost the same as in the first and second embodiments. That is, the address data is detected by looking at the duty of the exclusive OR processing result (bottom stage) of the binarized data at the second stage and the reference data at the third stage in FIG.
FIG. 5 shows that the detection method of FIG. 4 is strong against DC fluctuation of the wobble signal. When the DC level of the raw signal (top stage) changes, the duty ratio of the binarized signal changes, but it can be seen that there is almost no change in duty due to exclusive OR processing with the reference signal (third stage). . That is, it is strong against low frequency fluctuations of the reproduction (wobble) signal. In particular, this indicates that it is highly resistant to practical fluctuations (noise) such as leakage of recorded data during and after data recording, and wobble crosstalk of adjacent tracks. .
[Example 4]
FIG. 13 shows an example in which three types of M sequences are used as the wobble sequence of the present invention, and each of the M sequences is subjected to bi-phase modulation. For example,
If this method is applied when the unit wobble waveform itself has a DC component as in the third embodiment, the DC component can be made zero, which is effective in eliminating the influence on the reproduction signal and the servo signal.

  Although the unit wobble waveform of FIG. 1 seems to have a DC component at first glance, in the case of the example of FIG. 1, the unit wobble waveform having two sets of DC components in which the number of unit wobbles is different is alternately repeated. Since no component is produced, there is no method to apply the method of this embodiment.

FIG. 14 shows the correlation function of the series of FIG. 13, and very good correlation characteristics are obtained.
[Example 5]
FIG. 15 shows a unit wobble waveform according to another embodiment of the present invention. The wobble of this embodiment is obtained by adding a 180-degree phase modulation waveform with an angular frequency 2ω to an unmodulated basic waveform with an angular frequency ω.

  Appropriate band-pass filter makes it possible to separate the non-modulated component from the modulated component. When reproducing the modulated component, a stable clock generated from the modulated component can be used. Excellent characteristics.

The figure which shows one Example of the wobble waveform of this invention, and the elements on larger scale of an optical disk. The figure which shows the wobble waveform of one Example of this invention. The figure which shows an example of the reproduction | regeneration system of the wobble waveform of one Example of this invention. The figure which shows an example of the reproduction | regeneration system of the wobble waveform of one Example of this invention. The figure which shows the utility of the reproduction | regeneration system of the wobble waveform of this invention. The figure which shows the structural example of the wobble row | line | column of this invention. The autocorrelation function and cross-correlation function of the wobble sequence of the present invention. The figure which shows the structure of the synchronous frame of this invention. The figure which shows the structure of the address codeword of this invention. The figure which shows the structure of the error correction block for additional data of this invention. The figure which shows the block configuration of the recording / reproducing system of the optical disk of this invention. An example of the wobble detection circuit of the present invention. The figure which shows the structural example of the wobble row | line | column of this invention. The autocorrelation function and cross-correlation function of the wobble sequence of the present invention. The figure which shows the structural example of the wobble row | line | column of this invention. Conventional optical disc format.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 11 ... Groove, 12 ... Land, 13 ... Recording mark, 131 ... Recording mark, 2 ... Optical head, 21 ... Optical spot, 22 ... Light beam, 23 ... Objective lens, 24 ... Collimator lens, 25 ... Laser, 26 ... Detector, 27 ... Detector, 28 ... Beam splitter, 29 ... Hologram element, 31 ... Lens actuator, 41 ... Signal reproduction block, 50 ... Link part, 51 ... Data segment, 52 ... Gap region, 53 ... Guard area 54... Synchronization signal area 541... Synchronization signal 542. Resynchronization signal 55... Data area 56. Postamble 57 .. Recording unit 58. ... Mirror, 62 ... Pit area, 63 ... Address information pit, 64 ... Physical frame.

Claims (5)

An optical disc having at least one of a spiral or concentric groove portion or an inter-groove portion as an information recording area, wherein at least one of the groove portion or the inter-groove portion is formed by wobbling in a radial direction, and a plurality of wobbles The address code word for identifying the recording area is constituted by the address code word, and the address code word has additional data other than the address information in addition to the address information, and the additional data arranged in a plurality of address code words are grouped together An optical disk comprising a code block for error correction of additional data.   2. The optical disc according to claim 1, wherein management information or encryption key information for protecting data or restricting access during recording or reproduction is stored as the additional data.   2. The optical disk according to claim 1, wherein control information indicating the type and characteristics of the disk is stored as the additional data. At least one of spiral or concentric grooves or inter-grooves is used as an information recording area, and at least one of the groove or inter-groove is formed by wobbling in the radial direction, and the recording area is identified by a plurality of wobbles. Address code word is configured, and the address code word has additional data other than the address information in addition to the address information, and the additional data arranged in a plurality of address code words are grouped to add the additional data A method for reproducing information recorded on an optical disc in which a code block for error correction is configured is reproduced. At least one of spiral or concentric grooves or inter-grooves is used as an information recording area, and at least one of the groove or inter-groove is formed by wobbling in the radial direction, and the recording area is identified by a plurality of wobbles. Address code word is configured, and the address code word has additional data other than the address information in addition to the address information, and the additional data arranged in a plurality of address code words are grouped to add the additional data An information recording method for recording information on an optical disc in which a code block for error correction is configured.

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