JP2000057702A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk, an optical disk apparatus and an optical disk reproducing method, capable of performing stable and efficient readout of address information. SOLUTION: An optical disk 1a includes a plurality of tracks 1b each divided into a plurality of recording sectors. Each recording sector 1c includes a header region. In the header region, address information for identifying a position of the corresponding recording sector 1c and address synchronizing information for identifying a position where the address information is recorded and realizing bit synchronization are recorded. The address information has been modulated with a run length limited code having the maximum inversion interval of Tmax bits (where Tmax is a natural number), while the address synchronizing information includes two patterns with an inversion interval of (Tmax+3) bits or more, thereby discriminating a reproduced signal of the address synchronizing information from a reproduced signal of the other information. The address synchronizing information and a clock synchronizing information are recorded by utilizing first and second patterns in which either physical configurations or optical characteristics of a recording surface of the optical disk are different. The address synchronizing information includes a first pattern of (Tmax+3) bit length or more and a second pattern of (Tmax+3) bit length or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk for recording and reproducing digital signals, an optical disk apparatus, and an optical disk reproducing method.

[0002]

2. Description of the Related Art In recent years, optical disk devices have been attracting attention as means for recording and reproducing large-capacity data, and technical development for achieving higher recording densities has been actively conducted.

[0003] In the currently popular rewritable optical disk,
An uneven groove track (each having a width of about 50%) is formed spirally at a pitch of 1 to 1.6 μm on a disk substrate, and a recording material (Ge, in the case of a phase change optical disk, Ge, (Sb, Te, etc.) is formed by a method such as sputtering. A disk substrate is first prepared with a stamper based on an original master in which pits such as concave grooves and sector addresses are cut by irradiation with a light beam, and the stamper is used to replicate a large amount of a substrate such as polycarbonate. Since a rewritable optical disk requires management of data in units of sectors for recording and reproducing data, a guide groove for tracking control is formed at the time of manufacturing the disk, and at the same time, an address of each sector is formed by forming an uneven shape (pit) on a recording surface. Often records information.

[0004] For an optical disk having the above structure,
By irradiating each track with a light beam at a predetermined recording power, information is recorded by forming a mark on the recording thin film. Since the optical characteristics (reflection characteristics) of the recording thin film are different from those of the other portions at the portion irradiated with the recording light beam (recording mark), the track is irradiated with the light beam at a predetermined reproducing power to emit light from the recording film. Information is reproduced by detecting the reflected light.

In the following description, a pit having a physical unevenness and a recording mark obtained by modulating the optical characteristics of a recording thin film are collectively referred to as a "mark" unless otherwise specified. Once formed, the pits are read-only marks, and the recording marks are rewritable. In reproducing the recorded information, any mark is read as a change in the amplitude of the reproduced signal. In addition, the concave and convex shape in the following description indicates the concave and convex shape as viewed from the reproducing head of the optical disk device. That is, "pit" indicates a convex portion viewed from the reproducing head, and "groove" indicates a convex portion.

Techniques for achieving a higher recording density of an optical disk include a higher recording density in a track direction and a higher recording density in a linear velocity direction.

In order to increase the recording density in the track direction, the density (track pitch) of each track is reduced to increase the recording density. One method of narrowing the track pitch is land / groove recording in which a signal is recorded on both a convex track (groove section) and a concave track (land section). Compared to the case where a signal is recorded on either the groove portion or the land portion, land / groove recording can achieve twice the recording density when other conditions are the same.

As one method of increasing the density in the linear velocity direction, there is mark length recording in which both ends of a mark correspond to "1" of modulation data. FIG. 1 shows an example of mark length recording in comparison with inter-mark recording. In FIG. 1, a series Y indicates digital data modulated using a run length limited code. Here, the run length limited code is a code sequence in which the number of “0” s (hereinafter referred to as “zero run”) between bit sequences “1” and “1” is limited to a predetermined number. is there. An interval (length) from one "1" of the series Y to the next "1" is called an inversion interval. The limit of the zero run determines the limit of the inversion interval of the sequence Y, that is, the minimum value and the maximum value. These are called a minimum inversion interval and a maximum inversion interval.

[0009] Recording the sequence Y between marks (PPM: Pit Posi
When the recording is performed by the “Action Modulation”, “1” of the series Y
Corresponds to the recording mark 101, and zero run corresponds to the space 10
Corresponds to 2. Record the series Y with the mark length (PWM: Pulse
Width Modulation), the sequence Y
The appearance of 1 "switches the recording state, that is, the recording mark 101 or the space 102. In the case of mark length recording, the reversal interval corresponds to the length of the recording mark 101 or the space 102.

When a run length limited code having a minimum inversion interval of 2 or more is used, the number of bits per unit length can be increased in mark length recording as compared with inter-mark recording. For example, when the minimum values of the physical sizes of marks that can be formed on a disk (in units of marks) are equal, as can be seen from FIG. 1, the minimum code length data (3 bits of Y sequence “ Recording of 100 ") requires three mark units, but mark length recording allows recording in one mark units. For example, the recording density by the inter-mark recording is about 0.8 to 1.0 μm / bit, but the recording density in the case of the mark length recording is about 0.4 μm / bit.

Generally, a track on an optical disk is divided into recording sectors, which are minimum access units. Address information is recorded in advance in each recording sector as described above, and by reading this address information, each recording sector is accessed to record and reproduce data.

FIG. 2A shows a rewritable optical disk standardized by ISO (see ISO / IEC10090).
3 is a diagram showing a signal format of a recording sector of FIG. A header 104 is provided at the beginning of the recording sector 103, and addressing information for reading address information is recorded in advance by irregularities on the recording surface. Record field 105
Is an area for recording user data, in which digital data is modulated using a (2,7) modulation code and recorded between marks. FIG. 3 shows a conversion table of the (2, 7) modulation code. As shown in FIG. 3, the (2, 7) modulation gives i
Digital data having a bit length (i = 2, 3, 4) is converted into a code word having a length of 2 × i bits. Further, the (2, 7) modulation code is a run length limited code in which zero run is limited between 2 and 7.

FIG. 2B shows the structure of the header 104. The sector mark SM is provided so that the optical disc device can recognize the head of the recording sector without performing clock reproduction by a phase locked loop (hereinafter, referred to as PLL = Phase Locked Loop). As shown in FIG. 2C, a pattern using a relatively long mark is recorded in the sector mark SM, and a predetermined pattern of the sector mark SM and other data recorded between the marks due to its large reproduction signal amplitude are used. Can be distinguished. The position of the header 104 is detected by detecting the sector mark SM, and the address information is reproduced.

The VFO areas VFO1 and VFO2 shown in FIG. 2B are provided to synchronize the bit of a reproduction signal by performing clock reproduction by a PLL in the optical disc apparatus. Have been.

The address mark AM is provided for the optical disc apparatus to identify the byte synchronization of the following address fields ID1, ID2, and ID3. In the address mark AM, a pattern as shown in FIG. 2D is recorded between marks. The pattern of the address mark AM is
(2,7) Maximum inversion interval Tmax of modulation code (Tmax = 8)
Has a pattern of Tmax + 1 = 9 bits,
The pattern does not appear in the data recorded by the (2, 7) modulation code.

Address fields ID1, ID2, and ID3 include address information including a track number and a sector number, and a CRC (= Cy) for performing error detection during reproduction.
clicRedundancy Check) code is (2,7) modulated,
Recorded between marks.

The postamble PA is provided to indicate the end of (2, 7) modulated data of the address field ID3.

FIG. 4 shows a header 1 according to the optical disk device.
4 shows an example of the signal amplitude when the information recorded in 04 is reproduced. As can be seen from FIG. 4, the reproduction signal amplitude is proportional to the length of the mark,
The reproduction signal amplitude of M is larger than the reproduction signals of other data. Therefore, it is possible to determine the sector mark SM by detecting the envelope of the reproduction signal waveform and detect the head of each recording sector.

[0019]

In the above example, (2,
7) The modulated data is all recorded between marks. However, in the optical disk having the header 104 described above, when data is recorded with a mark length in order to improve the recording density, marks recorded in the address fields ID1 to ID3 in the header 104 and marks recorded in the recording field 105 are recorded. Has a length defined by the zero-run limit of the modulation code. Therefore, the amplitude of the reproduced signal of the data recorded with the mark length is larger than that between the marks where each mark corresponds to 1-bit length "1". Therefore, in the mark length recording, the difference (or the difference in the pattern) between the signal amplitude of the sector mark SM portion and the signal amplitude of the other portion becomes smaller than that in the case of the mark-to-mark recording. 10
It is difficult to detect the head of the number three.

The address mark AM as described above
Is adopted, there is a possibility that an erroneous detection of the address mark AM may occur due to an error such as a bit shift of “1”. For example, digital data {... 10110011.
7) The modulated code sequence can be obtained from the conversion table shown in FIG.
・ It becomes 0100100000001000 ...｝. On the other hand, the pattern of the address mark AM is $ 0100 as shown in FIG. 2D.
100000000100｝. Therefore, the same pattern as the address pattern AM appears by shifting the “1” of the (2, 7) modulation pattern by one bit, and is erroneously detected.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enable reliable reading of address information even when recording density is increased by employing mark length recording or the like. It is an object of the present invention to provide a possible optical disk, an optical disk device and an optical disk reproducing method.

[0022]

An optical disk according to the present invention includes a plurality of tracks divided into a plurality of recording sectors, each recording sector including a header area, and the header area includes a header area of a corresponding recording sector. Address information for identifying a position and address synchronization information for identifying a recording position of the address information and performing bit synchronization are recorded. The address information is a maximum inversion interval Tmax bits (Tmax is a natural number)
, And the address synchronization information has a reversal interval of (Tmax + 3) bits or more.
And the reproduced signal of the address synchronization information is distinguished from the reproduced signal of the other information, thereby achieving the above object.

In one embodiment, the address synchronization information is recorded using first and second patterns which are different from each other in physical shape and optical characteristics of the recording surface of the optical disk. The information is one (T
It includes a first pattern having a length of at least (max + 3) bits and a second pattern having a length of at least one (Tmax + 3) bits.

The first pattern is a convex portion (pit) physically formed on the recording surface of the optical disk, and the second pattern is a concave portion physically formed on the recording surface. There are cases.

The first pattern may be a recording mark having a changed reflection characteristic on the recording surface of the optical disk, and the second pattern may be a space on the recording surface.

Preferably, the total bit length of the first pattern and the total bit length of the second pattern included in the address synchronization information are equal.

Preferably, in the header area, the address information and the address synchronization information are repeatedly recorded four times.

The optical disk according to the present invention has a plurality of tracks divided into a plurality of recording sectors, the recording sectors include a header area, and the header area is used to identify a position of a corresponding recording sector. Address information, address synchronization information for identifying a recording position of the address information and performing bit synchronization, and clock synchronization information for reproducing a clock signal are recorded. The address information includes a minimum inversion interval Tmin bit and a maximum inversion interval Tmax bit (Tmax
And Tmin are modulated using a run length limiting code of Tmax> Tmin), and the clock synchronization information is d bits (d is a natural number satisfying Tmin ≦ d <Tmax).
The address synchronization information has a reversal interval of (Tmax
(+3) bits or more, so that the reproduction signal of the address synchronization information is distinguished from the reproduction signal of other information, thereby achieving the above object.

In one embodiment, the address synchronization information and the clock synchronization information are different from each other in a physical shape and an optical characteristic of a recording surface of the optical disc.
The address synchronization information includes a first pattern having one (Tmax + 3) bit length or more, and a second pattern having one (Tmax + 3) bit length or more. .

In one embodiment, the minimum inversion interval Tmin is 3, the maximum inversion interval Tmax is 11, and the d is 3.

In another embodiment, the minimum inversion interval Tmin is 3, the maximum inversion interval Tmax is 11, and the d is 4.

Preferably, in the header area, the clock synchronization information, the address information, and the address synchronization information are repeatedly recorded four times.

An optical disc according to the present invention has a plurality of tracks divided into a plurality of recording sectors, each recording sector including a header area and a postamble area provided at the end of the header area. The postamble area records a pattern determined based on the result of modulation of the data in the header area, thereby achieving the above object.

In one embodiment, the data in the header area is modulated using a modulation code for changing a table based on a state, and the postamble area includes information for identifying the state.

The information for identifying the state is at least one specific bit having a predetermined value, and the bit adjacent to the specific bit may have substantially the same value as the predetermined value of the specific bit. is there.

The optical disk according to the present invention includes a plurality of tracks divided into a plurality of recording sectors. Each recording sector includes a header area, a data recording area, and a post provided at the end of the data recording area. The postamble area includes an amble area, and the postamble area records a pattern determined based on a modulation result of data in the data recording area, thereby achieving the above object.

In one embodiment, the data in the data recording area is modulated using a modulation code for changing a table based on a state, and the postamble area includes information for identifying the state. .

The information for identifying the state is at least one specific bit having a predetermined value, and bits adjacent to the specific bit may have substantially the same value as the predetermined value of the specific bit. is there.

In one embodiment, the recording sector further includes a guard data recording area for recording dummy data after the postamble area.

In one embodiment, the data recording area has a minimum inversion interval Tmin bit and a maximum inversion interval Tmax.
Bits (Tmax and Tmin are natural numbers satisfying Tmax> Tmin) record data modulated using a run length limiting code, and the guard data recording area has k bits (k bits).
(A natural number satisfying Tmin ≦ k ≦ Tmax) has a pattern in which marks and spaces are alternately repeated.

The optical disc according to the present invention has a plurality of tracks divided into a plurality of recording sectors, each recording sector has a header area, and the header area has an address area having a postamble area at the end thereof. The postamble area includes a pattern in which non-pit data or space is arranged at the end of the postamble area, thereby achieving the above object.

The header area may include a plurality of the address areas.

The address area may be provided at an intermediate position between the groove and the land of the track.

The optical disc according to the present invention has a plurality of tracks divided into a plurality of recording sectors, each recording sector has a header area, the header area has a plurality of address areas, and each address area has Has a pattern in which non-pit data or space is recorded at the head thereof, thereby achieving the above-mentioned object.

In one embodiment, the address area has an address information area in which address information for identifying a position of the corresponding recording sector is recorded in a mark length.
The address information is modulated using a run length limiting code having a minimum inversion interval Tmin bit and a maximum inversion interval Tmax bit (Tmax and Tmin are natural numbers satisfying Tmax> Tmin). Non-pit data or space having a length equal to or less than the Tmax bit length is provided.

The address area may be provided at an intermediate position between the groove and the land of the track.

An optical disc device according to the present invention is an optical disc having a plurality of tracks divided into a plurality of recording sectors, each recording sector including a header area and a data area, and the header area corresponding to a corresponding recording sector. Address information for identifying the position of the address information, address synchronization information for identifying the recording position of the address information and performing bit synchronization, and clock synchronization information having a predetermined continuous pattern. An optical disk device. The apparatus includes means for reading a reproduction signal from the optical disc, address reproduction means for obtaining the address information from the reproduction signal, and detection for outputting the detection signal by detecting the continuous pattern of the clock synchronization information from the reproduction signal. Means, and address reproduction permission means for permitting the address reproduction means to read the address information based on the detection signal, thereby achieving the above object.

In one embodiment, the optical disc apparatus comprises: a clock generating means for generating a clock signal from the reproduction signal; and a clock for permitting the clock generating means to generate the clock signal based on the detection signal. Reproduction permission means.

The detecting means includes a binarizing means for binarizing the reproduced signal and outputting binarized data, a sampling means for sampling the binarized data at a predetermined frequency and outputting digital data. A parallel conversion means for converting the digital data into parallel data of at least m × n bits (m and n are natural numbers), and a detection table for detecting a predetermined sequence in which the m-bit pattern is continuous n times from the parallel data. , In some cases.

A disk device according to the present invention is an optical disk provided with a plurality of tracks divided into a plurality of recording sectors, each recording sector including a header area and a data area, and the header area includes a corresponding recording sector. Optical disk device for recording address information for identifying the position of the address, address synchronization information for identifying the recording position of the address information and performing bit synchronization, and clock information having a predetermined continuous pattern It is. The apparatus includes means for reading a reproduction signal from the optical disc, clock generation means for generating a clock signal from the reproduction signal, and detection for outputting the detection signal by detecting the continuous pattern of the clock synchronization information from the reproduction signal. Means, and clock reproduction permission means for permitting the clock generation means to generate the clock signal based on the detection signal, thereby achieving the object described above.

In one embodiment, the detecting means comprises:
A binarizing means for binarizing the reproduced signal and outputting binarized data; a sampling means for sampling the binarized data at a predetermined frequency to output digital data; It comprises a parallel conversion means for converting into parallel data of n bits (m and n are natural numbers), and a detection table for detecting a predetermined sequence in which an m-bit pattern is repeated n times from the parallel data.

The reproducing method of the optical disk according to the present invention is an optical disk having a plurality of tracks divided into a plurality of recording sectors, wherein each recording sector includes a header area and a data area, and the header area corresponds to the header area. Playback of an optical disk on which address information for identifying the position of a recording sector, address synchronization information for identifying the recording position of the address information and performing bit synchronization, and clock information having a predetermined continuous pattern are recorded. Is the way. The method comprises the steps of: extracting a playback signal from the optical disc; detecting the continuous pattern of the clock synchronization information from the playback signal; and allowing reading of the address information when the continuous pattern is detected. Reading the address information from the reproduction signal in accordance with the permission, and interrupting the step of reading the address information for a predetermined period after the permission and returning to the step of detecting the continuous pattern. Therefore, the above object is achieved.

[0053] In one embodiment, the method further comprises the steps of: permitting reproduction of a clock signal when the continuous pattern is detected; and reproducing the clock signal from the reproduced signal according to the permission. Include.

The method of reproducing an optical disc according to the present invention is an optical disc having a plurality of tracks divided into a plurality of recording sectors, each recording sector including a header area and a data area, and the header area corresponds to the header area. Playback of an optical disk on which address information for identifying the position of a recording sector, address synchronization information for identifying the recording position of the address information and performing bit synchronization, and clock information having a predetermined continuous pattern are recorded. Is the way. The method comprises the steps of: extracting a reproduction signal from the optical disc; detecting the continuous pattern of the clock synchronization information from the reproduction signal; and permitting reproduction of the clock signal when the continuous pattern is detected. Reproducing the clock signal from the reproduced signal according to the permission, thereby achieving the above object.

An optical disk reproducing method according to the present invention is an optical disk having a plurality of tracks divided into a plurality of recording sectors, wherein each recording sector includes a header area and a data area, and the header area corresponds to the header area. Playback of an optical disk on which address information for identifying the position of a recording sector, address synchronization information for identifying the recording position of the address information and performing bit synchronization, and clock information having a predetermined continuous pattern are recorded. Is the way. The method includes a step of extracting a reproduction signal from the optical disc and a step of determining a reproduction mode, wherein the initial mode is a period from power-on or after a track jump until the address information is first read from the reproduction signal. Determining the normal mode during a period from when the address information is read to when the next track jump is generated; detecting the continuous pattern of the clock synchronization information from the reproduced signal; A first permission step of permitting reading of the address information when the continuous pattern is detected, a step of reading the address information from the reproduction signal in accordance with the permission, and a step of reading the address information correctly. Generating a sector pulse; and in the normal mode, from the reproduction signal based on the sector pulse. A second permission step of permitting reading of the address information; and reading of the address information if the address information cannot be read within a predetermined time after permission of any of the first and second permission steps. And returning to the determination step of the reproduction mode, thereby achieving the above object.

[0056]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 5A shows an outline of an optical disc 1a according to a first embodiment of the present invention. As shown in FIG. 5A, a track 1b is formed in a spiral shape on the optical disc 1a, and the track 1b is divided into recording sectors 1c according to a predetermined physical format.
As shown in FIG. 5A, the recording sectors 1c are continuously arranged in the circumferential direction to form a track 1b.

FIG. 5B shows the format of each recording sector 1c of the optical disk 1a according to the first embodiment of the present invention. As shown in FIG. 5B, a header area 2 is provided at the head of the recording sector 1c, and addressing information for reading address information is recorded in advance. After the header area 2, a gap area 3, a data recording area 4, and a buffer area 5 follow in order. Data is not recorded in the gap area 3 and is used, for example, for power control of a semiconductor laser used for recording and reproducing data. User data is recorded in the data recording area 4. Digital data is generated by adding redundant data such as an error correction code to the user data. Digital data is modulated using a run length limited code with zero runs limited between 2 and 10. The modulated data is recorded in the data recording area 4 with a mark length. This run length limited code is called a (2, 10) modulation code. The buffer area 5 is provided to absorb rotation fluctuation of the optical disk and the like. Note that information recording in the header area 2 may be formed as pits due to irregularities on the recording surface, or optical recording marks may be formed in the same manner as recording in the data recording area.

As shown in FIG. 5C, the header area 2
Address areas 6a, 6b, 6c and 6d. Further, each address area has a VFO area, an address mark AM, and an address information area ID. For example, the address area 6a is a VFO area VFO
1, has an address mark AM, and an address information area ID1,
The address area 6b has a VFO area VFO2, an address mark AM, and an address information area ID2.

The conventional header 104 shown in FIG. 2B has a VFO after the sector mark SM recorded at the head.
Area, address mark AM and address field ID
Was repeatedly recorded three times.
In this embodiment, no sector mark is recorded in each header area 2, and a similar address area including a VFO area, an address mark AM, and an address information area ID is repeatedly recorded four times.

Each VFO area VFO1, VFO2, VFO3, VFO4 is
An optical disk device is used to reproduce a clock from a reproduction signal. As shown in FIG. 6, in each VFO area, a continuous pattern in which marks and spaces of 4-bit length appear alternately is recorded. The length of each VFO region may be the same or different. For example, by making only the VFO area VFO1 longer than the other VFO areas VFO2, VFO3, and VFO4, the clock reproduction at the head of the header area 2 can be stabilized.

The address mark AM is used by the optical disc apparatus to identify the position of the address information area ID following the address mark and to synchronize the bits. FIG. 7A shows an example of the address mark AM according to the present embodiment. As shown in FIG. 7A, a mark is recorded on the optical disk in accordance with a signal sequence (bit pattern) of the address mark AM. The signal to be read has a signal amplitude according to a pattern of a mark and a space (a part other than the mark). In this embodiment, the address mark AM is
This pattern includes one 14-bit mark and one 14-bit space. Address information area ID1, ID
The address information area ID is used to represent 2, ID3, and ID4.

In the address information area ID, digital data obtained by adding a predetermined error detection code to data including address information such as a track number and a sector number is modulated using a (2, 10) modulation code, and a mark length is obtained. Be recorded.

(2, 10) The maximum inversion interval of the modulation code is 1
1, the mark and space in each address information area ID or the pattern of the data recording area include 12
Those having a length of more than bits are not included. If the 11-bit mark in the address information area ID or the data recording area is erroneously set to 12 due to the edge shift of the mark or the like.
Bit in the address mark AM.
Even if the 4-bit mark is erroneously reproduced as 13 bits, there is still a 1-bit difference between them.
Therefore, unless one of the marks / spaces is edge-shifted by 2 bits or more, the 14-bit mark in the address mark AM cannot be detected or the address information area ID
There is no erroneous detection of a pattern in the data or data recording area as a 14-bit length mark. As described above, when the maximum inversion interval is Tmax, two patterns (marks and spaces) having a length of Tmax + 3 bits or more are recorded in the address mark AM, so that the address mark AM can be reliably detected. Can be.

As described above, 1 is included in the address mark AM.
By including a 4-bit mark / space twice,
The probability of erroneous detection is further reduced as compared to a pattern that is included only once. Furthermore, a pattern including a 14-bit length mark or space only once can be used as a data synchronization detection pattern in the data recording area 4. Thus, the reliability of the data synchronization detection is maintained, and the data synchronization detection pattern is not erroneously detected as the address mark AM.

FIGS. 7B and 7C show another example of the address mark AM. As the address mark AM, a pattern including two 14-bit length marks as shown in FIG.
A pattern including two 14-bit spaces as shown in FIG. 7C may be used. However, FIG. 7B or 7C
When a pattern as shown in (1) is used, there is a possibility that the entire recording pattern is biased toward either a mark or a space. As the overall pattern is biased towards either marks or spaces, the low frequency components of the pattern increase. An increase in the low frequency component of the pattern fluctuates the reproduction signal component in the servo band, and undesirably affects the servo system. Therefore, it is desirable that the low frequency component of the pattern be as small as possible, and a pattern in which the appearance balance between the mark and the space as shown in FIG. 7A is preferable.

8A to 8D show another example of the address mark AM. FIG. 8A shows an address mark of a pattern consisting of {6-bit mark, 14-bit space, 4-bit mark, 4-bit space, 14-bit mark, 6-bit space}.
Also, FIG. 8B shows a $ 4 bit mark, a 14 bit space, a 6 bit mark, a 6 bit space,
An address mark AM having a pattern consisting of a bit length mark and a 4-bit space｝ is shown. FIG. 8C shows a $ 5 bit mark, a 14 bit space, a 5 bit mark, a 5 bit space, a 14 bit mark,
An address mark AM having a pattern consisting of a 5-bit space 長 is shown. FIG. 8D shows an address mark AM having a pattern consisting of {4-bit mark, 14-bit space, 4-bit mark, 4-bit space, 14-bit mark, 4-bit space}.

In each of these patterns, the total number of bits in the mark portion is equal to the total number of bits in the space portion. Therefore, a 14-bit mark / space is included twice, and the low frequency component of the pattern is small.

Each of the patterns in FIGS. 8A to 8D has a larger number of mark / space inversions than the patterns in FIGS. 7A to 7C. The greater the number of mark / space inversions, the greater the edge information, and thus the greater the resistance to bit shift errors. That is, in each of the patterns of FIGS. 8A to 8D, the probability of occurrence of erroneous synchronization detection due to a bit shift is lower than in each of the patterns of FIGS.

In some cases, when the length of the address mark AM is set to an integer data byte, the processing of the modulation circuit, the demodulation circuit, and the like is simplified. FIG. 9 shows a pattern of the address mark AM when a modulation code in which one data byte becomes 16 bits after modulation is used. The length of the address mark AM is 48 bits, which is 3 data bytes. The pattern is $ 4-bit space, 4-bit mark, 14-bit space, 4-bit mark,
This pattern is composed of a 4-bit space, a 14-bit mark, and a 4-bit space.

Further, the pattern of the address mark AM shown in FIG. 9 has a larger number of mark / space inversions than the pattern of FIG. 7A. As described above, as the number of mark / space inversions increases, the edge information increases, so that errors due to bit shift become strong.
That is, the pattern of FIG. 9 has a lower probability of causing false synchronization detection due to the bit shift than the pattern of FIG. 7A.

FIG. 10 is a block diagram showing the configuration of an optical disk apparatus 100 for recording and reproducing data on and from the optical disk 1a having the above-described signal format. As shown in FIG. 10, the optical disc device 100 includes a spindle motor 7, a head 8, a preamplifier 9, a modulation circuit 11, a laser drive circuit 14, a reproduction system 16, a system control system 18,
And a servo system 50.

The spindle motor 7 rotates the optical disk 100 at a predetermined rotation speed. The head 8 includes a semiconductor laser, an optical system, a photodetector, and the like (not shown). Laser light emitted from a semiconductor laser is condensed by an optical system, and data is recorded and reproduced by irradiating a recording or reproducing light spot with a predetermined power to the recording surface of the optical disk 1a. The light reflected from the recording surface is condensed by an optical system and converted into a current by a photodetector. Head 8
Is further converted and amplified by a preamplifier 9 and output as a reproduction signal 10.

The servo system 50 controls the rotation of the spindle motor 7, the phase control for moving the head 8 in the radial direction of the optical disk 1a, the focus control for adjusting the focal point of the light spot to the recording surface of the optical disk 1a, and along the track center. To perform tracking control for tracking the light spot.

The modulation circuit 11 converts the input data 12 into (2,
10) Modulate and output the modulated data 13 to the laser drive circuit 14. During reproduction, the laser drive circuit 14
The laser drive signal 15 is output so that the semiconductor laser incorporated in the head 8 emits light at the power for reproduction. Also,
At the time of recording, the laser drive circuit 14 outputs a laser drive signal 15 so that mark length recording is performed in the data recording area 4 in accordance with the applied modulation data 13, and causes the semiconductor laser to emit light with recording power.

The reproduction system 16 converts the reproduction signal 10 supplied from the preamplifier 9 from the header area 2 and the data recording area 4
Is reproduced and output as reproduction data 17.

The system control system 18 controls the operations of the modulation circuit 11, the laser drive circuit 14, the reproduction system 16, and the servo system 50 based on the reproduction data 17 reproduced by the reproduction system 16 and the setting 19 from the user. I do.

FIG. 11 is a block diagram showing an example of the internal configuration of the reproduction system 16. Hereinafter, a method of reproducing the address information 40 recorded in the header area 2 from the reproduction signal 10 will be described. As shown in FIG. 11, the reproducing system 16 includes a clock reproducing circuit 20, a binarizing circuit 21, a VFO detecting circuit 2,
5, a reproduction permission circuit 32, an address demodulation circuit 30, and a data demodulation circuit 39.

The reproduction signal 10 from the preamplifier 9 is input to a clock reproduction circuit 20 and a binarization circuit 21. The clock recovery circuit 20 has a PLL,
A reproduction clock 22 synchronized with the frequency and phase of 0 is generated. The binarization circuit 21 equalizes the waveform of the reproduction signal 10 as necessary, and converts the waveform into a binary pattern composed of "1" and "0". The binarization circuit 21 uses the converted pattern as it is as the asynchronous binary data 23 as the VFO detection circuit 2.
5, and synchronizes the converted binary pattern using the reproduction clock 22 given from the clock reproduction circuit 20, and outputs it as synchronized binary data 24.
The synchronous binary data 24 is provided to the address demodulation circuit 30 and the data demodulation circuit 39.

The VFO detection circuit 25 generates VFO areas VFO1, VFO2, VFO3, and VF based on the asynchronous binary data 23.
A continuous pattern recorded in O4 is detected, and when a predetermined continuous pattern is detected, a VFO detection pulse 26 is output.

FIG. 12A shows an example of the internal configuration of the VFO detection circuit 25. As shown in FIG. 12A, the VFO detection circuit 25 includes a parallel conversion circuit 28, an oscillator 41, and a VFO detection table 42. Asynchronous binary data 23 and fixed clock 27 generated from oscillator 41
Is input to the parallel conversion circuit 28. The parallel conversion circuit 28 converts the asynchronous binary data 23 into a fixed clock 2
It latches at the timing of 7 and converts it into parallel data 29 for 32 consecutive clocks. The converted parallel data 29 is input to the VFO detection table 42.

The VFO detection table 42 is, for example, as shown in FIG.
It is composed of a table that gives 1 bit of output to 32 bits of input as shown in FIG. 2B. The VFO detection table 42 indicates that the parallel data 29 that is sequentially input at the timing of the fixed clock 27 has an 8-bit pattern [1111000].
0] or [00001111] is a pattern repeated four times, or a similar pattern thereof, when the VFO detection pulse 26
Is output as "1". In other patterns, the VFO detection pulse 26 becomes "0".

The pattern in the two rows from the top of the VFO detection table shown in FIG. 12B is a mark / space repetition pattern of a 4-bit length in which the frequency of the fixed clock 27 is substantially equal to the frequency of the reproduction clock, ie, the recording pattern of the VFO area Is a detection pattern in the case of completely matching Three
The pattern after the line is slightly different from the recording pattern in the VFO area. These patterns are provided so as to be detectable even when the amplitude of the reproduction signal 10 fluctuates or when the frequency of the fixed clock 27 is slightly different from the frequency of the reproduction clock due to fluctuations in the rotation of the disk 1a.

By using the VFO detection circuit 25 having such an internal configuration, a signal in the VFO area is generated by the fixed clock 27 corresponding to the frequency of the clock reproduced when the optical disk 1a is rotating at a predetermined rotation speed. Can be detected.

In this embodiment, the parallel data 29 for 32 clocks is used in order to detect a mark / space having a 4-bit length for four periods. However, the number of bits of the parallel data 29 is not limited to this. Absent. An optimal number of bits may be selected so as to reduce erroneous detection and omission in detection. Further, the frequency of the fixed clock 27 is not limited to this. For example, if it is made to correspond to the frequency of 1/4 of the reproduction clock, {10101010} or [0101010
1] can be detected as a VFO pattern.

The VFO area detection circuit 25 is shown in FIG.
Is not limited to a circuit having the internal configuration of For example, since the continuous pattern includes a specific frequency component, the continuous pattern can be detected by directly detecting the specific frequency component using the reproduced signal 10.

The address demodulation circuit 30 uses the synchronous binary data 24 and the reproduction clock 22 to generate an address mark AM.
Address information areas ID1, ID2, ID3, ID4
And (2, 10) demodulation of the modulated data recorded in the demodulator, and error detection of the demodulated data is performed.

As described above, in the present embodiment, the address area including the VFO area, the address mark AM, and the address information area ID is repeatedly recorded four times in each header area 2. Therefore, four address information areas ID1, ID2, ID3, ID4
When, for example, two or more pieces of address information can be reproduced without error, the reproduced value is output to the system control system 18 as the address information 40. The address demodulation circuit 30
Outputs the address information 40 and the sector synchronization pulse 31 at the same time.

Here, four recordings in the address area will be described. The error rate of one address is about 10 ^-2 . Assuming that address information can be obtained (addresses can be read) when at least two address areas in the four address areas are correctly reproduced, the probability that address information cannot be obtained is ₄ C ₃ × (10 ^-2 ) ³ × ( 1-10 ^-2 ) + (10 ^-2 ) ⁴
≒ 4 × 10 ^-6 . Here, _"4 C _3" is the number of combinations retrieving three of four things. Since one optical disc has about 10 ⁶ recording sectors,
The number of recording sectors whose addresses cannot be read in one optical disk is 10 ⁶ × (4 × 10 ⁻⁶ ) = 4. This number is acceptable. As described above, according to this embodiment, the number of recording sectors from which the address information cannot be read can be substantially reduced to less than 10, and each record can be identified very reliably.
Therefore, each recording sector can be identified by reliably extracting address information from the address area of the header of each recording sector without providing a sector mark SM for identifying the header at the head of the header.

Here, for comparison, a case of the conventional header 104 provided with three address areas (FIG. 2B) will be described. If the address can be read (address information can be obtained) when at least two of the three address areas are correctly reproduced, the probability that the address cannot be read is ₃
C ₂ × (10 ^-2 ) ² × (1-10 ^-2 ) + (10 ^-2 ) ³ ≒ 3
× 10 ^-4 . Here, “ ₃ C ₂ ” is the number of combinations that take two out of three. Since one optical disk has approximately 10 ⁶ recording sectors, the number of recording sectors whose addresses cannot be read on one optical disk is 10 ⁶ × (3 × 10 ^-4 ) = 300. This number is too large to be acceptable.

Returning to FIG. 11, the description will be continued. Reproduction permission circuit 3
2 is a VFO detection pulse 26 from the VFO detection circuit 25
A clock reproduction permission signal 34 is generated based on the reproduction gate signal 33 from the system control system 18 and output to the clock reproduction circuit 20. The clock recovery circuit 20
Only when the input clock reproduction permission signal 34 is “1”, the reproduction clock 22 is generated by synchronizing the built-in PLL with the phase of the reproduction signal 10 and output to the binarization circuit 21.

The reproduction permission circuit 32 generates an address reproduction permission signal 36 based on the VFO detection pulse 26 and the address gate signal 35 from the system control system 18, and outputs the signal to the address demodulation circuit 30. The address demodulation circuit 30 determines that the input address reproduction permission signal 36 is "1".
Only in the case of (1), the address mark AM is detected by identifying the pattern of the address mark AM as described above.

Further, the reproduction permission circuit 32 generates a data reproduction permission signal 38 based on the VFO detection pulse 26 and the data gate signal 37 from the system control system 18, and outputs the signal to the data demodulation circuit 39. Data demodulation circuit 3
9 is the data recording area 4 of the synchronized binary data 24 only when the input data reproduction permission signal 38 is “1”.
And demodulates the recording data read out from the CPU, and outputs reproduction data 17.

The system control system 18 has a sector synchronization pulse 31 given from the address demodulation circuit 30 of the reproduction system 16.
The reproduction gate signal 33, the address gate signal 35, and the data gate signal 37 are output at the timing according to the information format (that is, the reproduction signal format) shown in FIGS. These signals are
As described above, it is given to the reproduction permission circuit 32 of the reproduction system 16 (FIG. 11).

FIG. 13 is a waveform example showing the relationship among the sector synchronization pulse 31, the reproduction gate signal 33, the address gate signal 35, and the data gate signal 37.

As shown in FIG. 13, the reproduction signal format conforms to the information recording format shown in FIG. 5B, and the header area 2, gap area 3, and data recording area 4 of a certain recording sector 1A are respectively Header area 2a, gap area 3a, and data recording area 4
a. Similarly, recording sector 1 following recording sector 1A
B, the header area 2, the gap area 3, and the data recording area 4, respectively.
b and the data recording area 4b.

When the address information is correctly reproduced from the header area 2a in the recording sector 1A, the sector synchronization pulse 3 within the range of the gap area 3a from the end of the header area 2a.
1 becomes "1" (high level). Reproduction gate signal 33
Is the data recording area 4a of at least the recording sector 1A.
To cover the header area 2b of the next recording sector 1B. "
The address gate signal 35 is set to "1" so as to cover at least the header area 2b of the next recording sector 1B.
The data gate signal 37 is set to "1" so as to substantially cover the data recording area 4a of the recording sector 1A.

The system control system 18 looks at the contents of the address information 40 together with the sector synchronization pulse 31 and judges whether or not the recording sectors 1A and 1B have the target address information to be recorded or reproduced. Therefore, the configuration may be such that each gate signal is set to “1” at the above timing.

FIG. 14 shows a VFO detection pulse 26, a sector synchronization pulse 31, a reproduction gate signal 33, a clock reproduction permission signal 34, an address gate signal 35, an address reproduction permission signal 36, a data gate signal 37, and a data reproduction permission signal 38. Are shown in correspondence with the signal formats.

In FIG. 14, it is assumed that the address information is correctly reproduced for the first time in the recording sector 1A. It is also assumed that no data is recorded in the data recording areas 4a and 4b of the recording sectors 1A and 1B, and data is recorded in the data recording area 4c of the next recording sector 1C. It is assumed that a continuous pattern in which marks and spaces each having a 4-bit length alternately appear similarly to the VFO area is recorded at the head of the data recording area 4c in which data is recorded.

The clock reproduction permission signal 34 is set to "1" for a predetermined time after the generation of "1" of the VFO detection pulse 26. Further, the clock reproduction permission signal 34 is set to "1" even during the period when the reproduction gate signal 33 is "1". The predetermined time is set to at least a time required for reading the address mark AM and the address information areas ID1, ID2, ID3, and ID4 recorded in the header area 2. As a result, in each VFO area of the recording sector 1A, the VFO detection pulse
When it becomes "1", the clock reproduction permission signal 34 is at least "1" until the end of the header area 2a. Also, when the address information is correctly reproduced in the recording sector 1A and the sector synchronization pulse 31 is output. Is the clock reproduction enable signal 3 in the header area 2b of the subsequent recording sector 1B.
4 surely becomes "1". Similarly, when the address information is correctly reproduced in the recording sector 1B and the sector synchronization pulse 31 is output, the clock reproduction permission signal 34 is reliably set to "1" in the header area 2c of the subsequent recording sector 1C.

The address reproduction permission signal 36 becomes "1" during a predetermined time after the generation of "1" of the VFO detection pulse 26 and during a period when the address gate signal 35 is "1". The predetermined time is set to at least the sum of the time for reading information from the address mark AM and the address information areas ID1, ID2, ID3, and ID4. As a result, when the VFO detection pulse becomes "1" in each VFO area of the recording sector 1A, the address reproduction permission signal 36 becomes "1" at least up to the end of the header area 2a. When the address information is correctly reproduced in the recording sector 1A and the sector synchronization pulse 31 is output, the subsequent recording sector 1A is output.
In the header area 2b of B, the address reproduction permission signal 36
Is surely "1". Similarly, when the address information is correctly reproduced in the recording sector 1B and the sector synchronization pulse 31 is output, the header area 2 of the subsequent recording sector 1C is output.
In step c, the address reproduction permission signal 36 becomes "1" without fail.

If the data gate signal 37 is "1" when the VFO detection pulse 26 "1" is generated, the data reproduction permission signal 38 is "1" from that moment until the data gate signal 37 becomes "0". And On the other hand, if the data gate signal 37 is "0" when the VFO detection pulse 26 generates "1", the data reproduction permission signal 38 remains "0". As a result, in the data recording areas 4a and 4b where no data is recorded, the VFO
Since the detection pulse 26 does not become "1", the data reproduction permission signal 38 remains "0". In the data recording area 4c in which data is recorded, the VFO detection pulse is "1" at the head thereof, so that the data reproduction permission signal 38 becomes "1" at a predetermined timing.

As described above, by using the VFO detection circuit 25 and the reproduction permission circuit 32, the reproduction of the clock and the reproduction of the address information in the header area 2 are permitted, and the clock signal and the address information can be read. As described above, the sector synchronization pulse 31 is output only after the address information is reproduced from the header area 2 (see FIG. 13). Therefore, according to the present embodiment, it is possible to read the address information of the recording sector even when there is no time reference based on the sector synchronization pulse 31.

Also, by using the system control system 18, the address demodulation circuit 30, and the reproduction permission circuit 32,
When the address information is reproduced without error in one recording sector (for example, 1A), the clock reproduction and the reproduction of the address information in the header area 2 are permitted in the recording sector 1A and the next recording sector 1B, and the corresponding data is reproduced. Clock reproduction and data reproduction in the recording area 4 can be permitted. Therefore, once the address information is reproduced from one recording sector, the sector synchronization pulse 31
, The address information and the data can be read more reliably.

In the above example, the system control system 18 generates three types of gate signals using the sector synchronization pulse 31, and the reproduction permission circuit 32 generates three types of gate signals using the VFO detection pulse 26 and the three types of gate signals. However, the function of the reproduction permission circuit 32 may be provided in the system control system 18 so that the system control system 18 directly generates three types of permission signals.

FIG. 15 shows an optical disk device 100 (FIG. 1).
0), the system control system 18
Using the FO detection pulse 26 and the sector synchronization pulse 31, the clock reproduction permission signal 34 and the address reproduction permission signal 3
6 is a flowchart illustrating an example of a process when outputting No. 6;

When the power of the optical disk device 100 is turned on, the system control system 18 first performs a startup process (step 1). In the start-up processing, rotation control of the spindle motor 7 by the servo system 50, transfer control of the head 8,
The control includes power control of the semiconductor laser in the head 8, focus control of the optical system, tracking control, and the like. In the start-up process, the clock reproduction permission signal 34 and the address reproduction permission signal 36 are both reset to "0".

When the head 8 tracks on a predetermined track of the optical disk 1a, first, V
An FO area is detected (step 2). When "1" of the VFO detection pulse 26 is detected, the clock reproduction permission signal 34 is set to "1" (step 3). Subsequently, the address reproduction permission signal 36 is set to "1" (step 4). After a predetermined period, the address reproduction permission signal 3
6 and the clock reproduction permission signal 34 are reset to "0" (step 5), and the sector synchronization pulse 31 is detected (step 6).

When the address demodulation circuit 30 correctly reads the address information, the sector synchronization pulse 31 becomes "1". The address information 40 output from the address demodulation circuit 30 is read in synchronization with this signal. Is determined (step 7). If the read address information 40 is that of the target recording sector, the flow shifts to control for recording / reproducing (step 8). If the read address information 40 is not for the target recording sector,
The process proceeds to seek control (step 9).

When the address demodulation circuit 30 fails to read the address information, the process returns to the VFO detection step 2 again because the sector synchronization pulse 31 does not become "1" for a predetermined period in step 6.

By the processing according to the flow described above,
The clock reproduction permission signal 34 and the address reproduction permission signal 36 are generated at the timing shown in FIG. 14, and even when there is no time reference by the sector synchronization pulse 31 before the address information is reproduced after the power is turned on, the operation is smoothly performed. The address information can be read.

FIG. 16 is a flowchart showing an example of the processing of the system control system 18 when the processing method is switched between the initial mode and the normal mode. Here, the initial mode is a period from when the power is turned on or after a track jump due to a seek or the like until the address information is first reproduced, and in the normal mode, the predetermined address information is read and then the next. This is until a track jump occurs.

In FIG. 16, the processing from step 1 to step 9 is the same as the corresponding processing in FIG. 15, and a description thereof will be omitted.

As shown in FIG. 16, in step 10, it is determined whether the mode is the initial mode or the normal mode. If the address information has already been correctly read in the processing up to this point and recording / reproducing has been performed on the target recording sector, it is determined that the mode is the normal mode. After the start-up process (step 1), after the address information reading failed in step 6, or the address information was read but it was determined in step 7 that it was not the target recording sector, and seek control was performed (step 9). Later, it is determined that the mode is the initial mode.

In the normal mode, the VFO detection processing (step 2) is not performed, and the processing of steps 3, 4 and 5 is performed based on the timing when the sector synchronization pulse 31 becomes "1". In the initial mode,
First, VFO detection processing (step 2) is performed, and then VF
Steps 3, 4, and 5 are performed based on the timing at which the O detection pulse 26 becomes "1".

By the above-described processing, the address information can be read smoothly after the power is turned on or after the track jump, and after the address information has been reproduced, the address information can be more reliably determined based on the sector synchronization pulse 31. And data can be read.

As described above, in the first embodiment, FIGS. 5B and 5C
The optical disk 1a having the signal format shown in FIG.
The method of recording / reproducing using the optical disk device 100 having the block configuration shown in FIG. 0, in particular, the method of reading address information has been described.

Note that, in the first embodiment, the header area 2
Although the (2, 10) modulation code is used as the modulation code in each address information area ID and the data recording area 4, the modulation code is not limited to this. Any type of run length limited code having a determined maximum inversion interval may be used, and the pattern of the address mark AM may be determined so as to satisfy the above-described condition for the maximum inversion interval Tmax.

In the first embodiment, the information recorded in each VFO area has been described as a 4-bit mark / space continuous pattern shown in FIG.
The pattern of the area is not limited to this. The length of each mark or space may be at least the minimum inversion interval Tmin of the modulation code (run length limit code) used for recording the address information area ID and less than the maximum inversion interval Tmax. However, as in the above-described example, a short mark / space pattern that is as close as possible to the minimum inversion interval Tmin has a larger repetition period per unit length, and thus can reproduce a clock at a higher speed.

In this embodiment, each address mark A
7A to 7C, FIGS. 8A to 8D, and FIG.
Has been described, but the pattern of the address mark AM is not limited to this. The address mark AM can be detected if the pattern includes two times a pattern having a length of at least the maximum inversion interval Tmax + 3 bits of the modulation code (run length limit code) used for recording the address information area ID.

Further, in this embodiment, an example has been described in which the header area 2 includes four address areas, but the configuration of the header area 2 is not limited to this. For example, 1
Even if it is configured to include only one address area, it is possible to reproduce the address information. However, by recording a plurality of address area IDs in which the same address information is recorded, it is possible to improve the reliability of reading the address information. As described above, it is preferable to record four or more address areas in each header area 2 in consideration of the error rate of the address information and the allowable range of the number of unidentifiable recording sectors. Further, in view of the practical allowable range and the maximum securing of the data recording area 4, the header including the four address area IDs described in the first embodiment is more preferable.

(Embodiment 2) FIG. 17A is a diagram showing a format of a recording sector 51 of an optical disc according to a second embodiment of the present invention. As shown in FIG. 17A, a header area 52 is provided at the beginning of the recording sector 51, and addressing information for reading address information is recorded in advance. After the header area 52, a gap area 53, a data recording area 54, a postamble PA0, a buffer area 5
5 follows in order.

Data is not recorded in the gap area 53, but is used for, for example, power control of a semiconductor laser used for recording and reproducing data. User data is recorded in the data recording area 54. Digital data is generated by adding redundant data such as an error correction code to the user data. The digital data is modulated using a run length limit code generated using a state machine, and recorded in a data recording area 54 with a mark length. This run length limited code is called a state modulation code. At the end of the data recording area 54, a postamble PA0 is provided. Postamble P
The pattern of A0 is determined based on the modulation result of the data recording area 54. The buffer area 55 is provided to absorb fluctuations in the rotation of the optical disk and the like. The header area 52
May be formed as pits due to irregularities on the recording surface, or optical recording marks may be formed in the same manner as recording in the data recording area.

The header area 52 is divided into four address areas 56a, 56b, 56c and 56d as shown in FIG. 17B. Further, each address area includes a VFO area, an address mark AM, and an address information area I.
D, and postamble PA. For example, the address area 6a includes a VFO area VFO1, an address mark A
M, an address information area ID1, and a postamble PA1.
The address area 6b has a VFO area VFO2, an address mark AM, an address information area ID2, and a postamble PA2. The address information areas ID1, ID2, ID3, and ID4 are represented as address information area IDs. Also, the postamble PA1, PA2, PA3, and PA4 is represented as a postamble PA.

In this embodiment, as in the first embodiment, no sector mark is recorded in each header area 52.
VFO area, address mark AM, address information area I
A similar address area including D and postamble PA is repeatedly recorded four times.

Each VFO area VFO1, VFO2, VFO3, VFO4 is
An optical disk device is used to reproduce a clock from a reproduction signal. In each VFO area, for example, similar to the first embodiment, a continuous pattern in which marks and spaces of a fixed length (for example, 4 bits) appear alternately. The length of each VFO region may be the same or different. For example, by making the head VFO area VFO1 longer than the other VFO areas, the clock reproduction at the head of the header area 52 can be stabilized.

The address mark AM is used by the optical disc apparatus to identify the position of the address information area ID following it. For example, like the address mark AM used in the first embodiment, the maximum of the state modulation code is inverted. Interval Tmax
The pattern includes a pattern of +3 bit length twice.

In the address information area ID, digital data obtained by adding a predetermined error detection code to data including address information such as a track number and a sector number is modulated by using a state modulation code and recorded with a mark length.

FIGS. 18A to 18C are schematic diagrams for explaining a modulation method and a demodulation method of the state modulation code used in this embodiment. The state modulation code is a modulation code for converting 8-bit binary data into a 16-bit code sequence. A 16-bit output code sequence Yt for 8-bit input data Dt at a certain time t is determined based on the state St at that time t. FIG. 18A
Shows a configuration example of the state modulation circuit 60. FIG.
8A, the state modulation circuit 60 has a conversion table 56 and a D flip-flop 57. The data Dt and the state St at the time t are input to the conversion table 56, and the code sequence Yt and the state St + 1 at the next time t + 1 (hereinafter, referred to as next state) are output. The next state St + 1 output from the conversion table 56 is input to the D flip-flop 57 and used for the next modulation.

FIG. 18B shows a part of the contents of the conversion table 56. The state St at each time has four states in total from St = 1 to 4, and a different code sequence Yt is assigned to each state. State St at each time
And the data Dt, the next state St + 1 is determined. The 16-bit sequence assigned to the table as the output code sequence Yt is a run length limited code in which zero runs are restricted between 2 and 10. Even when a sequence between two times is connected, zero runs are performed. Is determined between 2 and 10, the next state St + 1 is determined.

Further, among the 16-bit sequences assigned to the table as the output code sequence Yt, those whose next state St + 1 is 1 or 2 are determined so that the last zero run is 5 or less.

In some cases, the same output sequence Yt is assigned at two locations to different input data dt, such as the underlined patterns p1 and p2 in the table. In such a case, the state is determined to be either state 2 or state 3 so that the next state is always different. For example, in this example, p1 is the next state 2 and p2 is the next state 3. I have. Except for such a case, the same output sequence Yt is not redundantly assigned to two locations.

The code sequence Yt belonging to state 2 and state 3 has the following properties. In the output sequence Yt belonging to state 2, the first bit and the 13th bit from the left end are both "0", and in the output sequence Yt belonging to state 3, one of the first bit and the 13th bit from the left end is "1".
It is.

In the demodulation of the state modulation code, it is necessary to convert the 16-bit code sequence Yt into 8-bit binary data, contrary to the modulation. FIG. 18C shows the demodulation circuit 6
1 is a block diagram illustrating the configuration of FIG. In the demodulation circuit 61, a 16-bit code sequence Yt at a certain time t
And 1 of the code sequence Yt + 1 at the following time t + 1
Total 1 of bit Yt + 1_1 and bit 13 Yt + 1_13
Eight bits are input to the inverse conversion table 58. The output of the inverse conversion table 58 at each time t becomes 8-bit binary data Dt.

The structure of the reverse conversion table 58 is basically the reverse of the conversion table 56 shown in FIG. 18B. In the code sequence Yt, for a pattern that is not assigned repeatedly, the binary data Dt as a demodulation result is uniquely determined.

On the other hand, for a pattern assigned redundantly, such as p1 and p2 in state 1 shown in FIG. 18B, binary data Dt cannot be uniquely determined only by code sequence Yt. However, as described above, the same code sequence Yt is assigned redundantly only when the next states of the two are 2 and 3. Accordingly, the original binary data D
It is possible to determine t uniquely. That is, at the time of modulation, the binary data Dt is uniquely determined by looking at the first bit and the thirteenth bit of the code sequence at time t + 1, which is the code sequence determined by the next state at time t.

In each address information area ID, mark length data including address information modulated using the above-described modulation method is recorded.

The postamble PA0 shown in FIG.
Indicates the end of the data recording area 54, and its pattern is determined based on the modulation result of the data recording area 54.

Each of the postambles PA1, PA2, PA3, and PA4 shown in FIG. 17B indicates the end of each address area 56a to 56d, and the pattern is the corresponding address information recorded immediately before. Area ID1, ID2, ID
3, and is determined based on the modulation result of ID4.

FIGS. 19A and 19B show an example of a postamble pattern. 19A and 19B, the next state means the next state when the immediately preceding data is modulated. That is, for the postamble PA0, the next state when the data at the end of the data recording area 54 is modulated, and the postamble PA1, PA2, PA
3, corresponding address information area ID1, ID2, ID for PA4
3 and the next state when the data at the end of ID4 is modulated. When the next state is state 1 or state 2, the pattern p3 shown in FIG. 19A is selected as the postamble. When the next state is 3 or 4, the pattern p4 shown in FIG. 19B is selected as the postamble. The selected postamble is recorded with the mark length.

When the pattern p3 is connected to all code sequences whose next state is state 1 or state 2, the zero run is 2 to 1 even at the connection portion.
Limited to 0. Even when the pattern p4 is connected to all the code sequences whose next state is state 3 or state 4, the zero run is limited to 2 to 10 at the connection. Therefore, the run length limit is not broken by adding the postamble. Also, the first bit of the pattern p3 and 13
The bits are both "0". On the other hand, the first bit of the pattern p4 is "1".

By using such patterns p3 and p4 as each postamble, the data recording area 5
4 or the pattern recorded at the end of each address information area ID1, ID2, ID3, ID4 can be uniquely demodulated.

As a further characteristic, the pattern p3
Is a specific bit for identifying the state (the first bit and the 13th bit).
The second bit, the twelfth bit, and the fourteenth bit, which are adjacent bits to (bit), are all “0”. As a result, it is possible to prevent the 13th bit from being erroneously recognized as "1" due to a bit shift or the like, thereby preventing the state from being erroneously demodulated.

(Embodiment 3) FIG. 20A shows an outline of an optical disc 201a according to a third embodiment of the present invention. FIG. 20A
As shown in FIG. 2, a track 201b is formed in a spiral shape on an optical disc 201a.
01b is a recording sector 2 according to a predetermined physical format.
01c. As shown in FIG. 20A, the recording sectors 201c are continuously arranged in the circumferential direction to form a track 201b.

FIG. 20B shows a format of each recording sector 201c of the optical disc 201a according to the third embodiment of the present invention. As shown in FIG. 20B, the recording sector 201
At the beginning of c, a header area 202 is provided, and addressing information for reading address information is recorded in advance. After the header area 202, a gap area 203,
A data recording area 204 and a buffer area 205 follow in order. No data is recorded in the gap area 203,
For example, it is used for power control of a semiconductor laser used for recording and reproducing data. User data is recorded in the data recording area 204. Digital data is generated by adding redundant data such as an error correction code to the user data.
The digital data is modulated using a run length limited code in which the zero run is limited between 2 and 10, that is, a (2,10) modulation code. The modulated data is recorded in the data recording area 204 with a mark length. The buffer area 205 is provided to absorb fluctuations in the rotation of the optical disk and the like.
Note that information recording in the header area 202 may be formed as pits due to irregularities on the recording surface, or optical recording marks may be formed in the same manner as recording in the data recording area.

As shown in FIG. 20C, the header area 202 has four address areas 206a, 206b, and 206.
c and 206d. Further, each address area has a VFO area, an address mark AM, an address information area ID, and a postamble PA.
For example, the address area 206a has a VFO area VFO1, an address mark AM, an address information area ID1, and a postamble PA1, and the address area 206b has a VFO area VFO1.
It has FO2, address mark AM, address information area ID2, and postamble PA2. The address information area ID1, ID
The address information area ID is used to represent 2, ID3, and ID4.
Also, the postamble PA1, PA2, PA3, and PA4 are represented as a postamble PA.

In this embodiment, similarly to the above-described embodiment, no sector mark is recorded in each header area 202, and a similar structure including a VFO area, an address mark AM, an address information area ID, and a postamble PA is used. The address area is recorded four times repeatedly.

Each VFO area VFO1, VFO2, VFO3, VFO4 is
An optical disk device is used to reproduce a clock from a reproduction signal. In each VFO area, for example, similar to the first embodiment, a continuous pattern in which marks and spaces of a fixed length (for example, 4 bits) appear alternately. The length of each VFO region may be the same or different. For example, by making the first VFO area VFO1 longer than other VFO areas, the header area 202
At the beginning of the clock can be stabilized.

The address mark AM is used by the optical disc device to identify the position of the address information area following the address mark AM. For example, the address mark AM used in the first embodiment is used.
Similarly to the above, the pattern includes the pattern of the maximum inversion interval Tmax + 3 bit length of the modulation code (run length limit code) twice.

In the address information area ID, digital data obtained by adding a predetermined error detection code to data including address information such as a track number and a sector number is modulated using a (2, 10) modulation code, and a mark length is obtained. Be recorded.

FIG. 21A shows the arrangement of address areas in the header area 202 recorded on the recording surface in the optical disc according to the present embodiment. As shown in FIG. 21A, on an optical disc, information is recorded on both groove tracks and land tracks. 210 and 212 indicate groove tracks, and 211 indicates a land track. Address areas 213 to 2 are arranged so as to straddle adjacent groove tracks and land tracks.
20 are formed. Here, the address area 213,
217 corresponds to 206a. Address area 214, 2
18 corresponds to 206b. Address areas 215, 21
9 corresponds to 206c. Address area 216, 220
Corresponds to 206d. The distance between the center line of the land track and the center line of the groove track is the track pitch Tp
Each address area is alternately shifted from the track center by Tp / 2 toward the inner peripheral side and the outer peripheral side. For example, along the center line 230 of the groove track 210, address areas 213 to 216 are alternately arranged on both sides thereof. Reference numeral 207 denotes a light spot. At the time of reproduction, address information is read from the address areas 213 to 216 along the groove track 210, and the address area 21 is read along the land track 211.
Address information is read from 7, 214, 219, and 216. By arranging the address areas in this manner, the address information can be read from both the land track and the groove track.

Next, a method of forming a master disk for forming a stamper used for forming a disk substrate having an address area as the above-mentioned convex groove track and uneven pits will be described. The track and the address area are formed by irradiating the rotated master disc with a cutting laser beam. When a laser beam is continuously irradiated, a groove track is formed as one continuous groove. Laser light ON / OFF intermittently
Then, the portion irradiated with the laser beam is formed as a mark (pit data) in the address area. The portion not irradiated with the laser beam becomes a space (non-pit data). For example, a predetermined pattern as described in the above embodiment is recorded by a combination of a mark and a space. Further, in this embodiment, since the address area is shifted from the center of the track to the inner and outer circumferences (wobble arrangement), the center of the cutting laser beam is shifted in the radial direction by a predetermined amount Tp / 2 for each address area. Turn ON / OFF the light. In the manufacture of the master disc, cutting is performed from the surface opposite to the recording surface at the time of reading. Therefore, the unevenness of the pits and grooves is opposite to that when viewed from the reproducing head at the time of reading. FIG. 21B shows another example of the arrangement of the address areas in the header area 202 recorded on the recording surface in the optical disc according to the present embodiment. In the optical disc shown in FIG. 21B, information is recorded on both groove tracks and land tracks. 210 and 2
12 indicates a groove track, and 211 indicates a land track. Address areas 213 to 220 extend over adjacent groove tracks and land tracks.
Are formed. Here, the address areas 213 and 21
7 corresponds to 206a. Address areas 214, 218
Corresponds to 206b. Address areas 215 and 219 correspond to 206c. Address areas 216 and 220 are 2
06d. The distance between the center line of the land track and the center line of the groove track is the track pitch Tp, and the two previous address areas (213, 214, 21)
7 and 218) are shifted from the groove track center line 230 by Tp / 2 toward the outer periphery, and the two subsequent address areas (215, 216, 219 and 220) are shifted from the groove track center line 230 by Tp / Tp / 2. It is displaced by two to the inner peripheral side. Reference numeral 207 denotes a light spot. During reproduction, address information is read from the address areas 213 to 216 along the groove track 210, and address information is read from the address areas 217, 218, 215, and 216 along the land track 211.

By arranging the address areas in this way, address information can be read from both land tracks and groove tracks.

In addition, since the outer circumference and the inner circumference are shifted in units of two address areas, the number of times that the center of the cutting laser beam is shifted by Tp / 2 in the radial direction when the master disc is formed. As compared with the arrangement shown in FIG. 21A, the number is reduced, and the cutting of the master optical disc is facilitated.

At the time of manufacturing the optical disc master, FIG.
As shown in FIG. 1A (FIG. 21B), first, a groove 210 and address areas 213, 214, 215, and 216 on both sides thereof are formed. Thereafter, after the disc master makes one rotation, the groove 212 and the address areas 21 on both sides thereof are formed.
7, 218, 219, and 220 are formed. At this time, since the rotational accuracy of the disc master varies, the circumferential position of the address area 213 does not always match the corresponding address area 217 along the radial direction of the optical disc. As shown in FIG. 21A (FIG. 21B), when the ends of the address areas 213 and 217 are formed shifted by ΔX, the end of the address area 217 (218) and the address area 21 when reproducing the land track 211 are reproduced.
4 (215) may overlap by ΔX and the address information may not be accurately reproduced.

Therefore, as shown in FIG. 21C, a space is arranged at the end of each address area without recording a mark, and further, at the head of the next address area, the rotational accuracy at the time of cutting the master disc ( A space (ΔX1) longer than ΔX) is arranged.

For example, the rotational accuracy at the time of cutting the master disc is approximately 20 when the rotational speed is 700 revolutions / minute.
ns / rotation. Therefore, in the case of an optical disk having a diameter of 120 mm, when the value of ΔX is converted into a length, the maximum ΔX =
It is about 0.1 μm.

The operation in this case will be described.

FIGS. 22A and 22B schematically show a connection between two address areas 213 (214) and 214 (215). The data array of the address area shown in FIGS. 22A and 22B has the address area 213 (21
The end (final pattern) of 4) is a mark, and the leading pattern of the subsequent address area 214 (215) is also a mark. FIG. 22A shows an ideally expected mark shape in the case of such a data array. That is, the tail mark of the address area 213 (214) and the head mark of the address area 214 (215) are formed at a specified length at the center of each address area. However, in reality, when address pits are formed while shifting the laser beam in each address area in the cutting process of the master disc, the address area 213 (2
If the mark is continuous at the connection between the address area 14) and the next address area 214 (215), the laser beam is continuously emitted while the cutting laser is shifted in the radial direction. Therefore, in actuality, as shown in FIG. 22B, the end mark of the address area 213 (214) and the start mark of the address area 214 (215) are formed continuously, and the illegal mark over the two address areas is formed. Is formed. As a result, it becomes difficult to correctly reproduce the data.

FIGS. 23A and 23B show a reading operation when the light spot 207 reproduces data from the land track 211. FIG.

FIG. 23A shows a case where the mark arrangement at the connection between two adjacent address areas is not specified. FIG.
As shown in FIG.
(215) and 217 (218) indicate the cutting accuracy Δ
When spatially overlapping at X, the data read from the two address areas temporally overlap by an amount corresponding to ΔX. Also, the address area 217 (218)
Has a space at the end, but the address area 214
The head of (215) is a mark. As shown in FIG. 23A, when the head mark of the address area 214 (215) overlaps the space at the end of the address area 217 (218), it is determined that the mark exists at the end of the address area 217 (218). Address area 217 (21
8) causes a data error.

FIG. 23B shows a data arrangement according to the present invention which solves the above problem. As shown in FIG. 23B, spaces are arranged at both the end and the head of the adjacent address area. With such an arrangement, the space at the end of the address area 217 (218) and the address area 21
4 (215), even if the leading space overlaps, the overlapping portion still becomes a space.
No data error occurs in (218). Although the length of the head space of the address area 214 (215) cannot be read correctly, generally, the head of each address area is a VFO area, and it is not always necessary to read all data. Further, if the address area is resynchronized by the address mark AM arranged after the VFO area and the address information can be correctly recognized, no problem occurs in the reading operation of the address area.

Also, even when cutting the master disc, since the space is always arranged between the adjacent address areas and the marks are not continuous, the laser beam is continuously irradiated at the time of shifting in the radial direction. Never. Therefore, a defective mark as shown in FIG. 22B is not formed.

As described above, by arranging spaces at the beginning and end of each address area as shown in FIG. 23B,
When the address area is wobbled, it is possible to prevent a mark formation defect at the time of cutting the disc master and a data reading error due to the overlap of the address area at the time of reproducing the address area.

Next, the postamble PA according to the present embodiment will be described.
The case where the mark arrangement is applied to the data array using the state modulation code described in the second embodiment (FIGS. 18A and 18B) will be described. 24A to 24D show an example of the mark arrangement of the postamble PA when using the state modulation code. 24A to 24D, each next state is the next state when the immediately preceding data is modulated. That is, the next state is obtained when the data at the end of the corresponding address information area ID is modulated.

FIG. 24A shows a case where the next state is state 1 or state 2 (see FIG. 18B), and the end of the address information area ID ends with a mark 240. In this case, the pattern p as shown in FIG.
5 {0010010010000000} is selected and the mark length is recorded. As described in the second embodiment, since the last zero run of each code sequence whose next state is state 1 or state 2 is 5 or less, all code sequences whose next state is state 1 or state 2 and the pattern p5 Is connected, the zero run is also limited to between 2 and 10 for that connection. The first bit and the thirteenth bit of the pattern p5 are both "0". Also, by selecting the pattern p5, the end of the postamble PA, that is, the end of the address area always becomes a space.

As a result, the start and end of each address area become a space, and between the address areas in which wobbles are arranged, mark formation defects during cutting of the master disc and data reading errors due to overlapping of the address areas during reproduction of the address areas. Can be prevented.

Further, the pattern of the VFO area arranged at the head of each address area is defined as $ 000100010001000.
By using a continuous pattern signal starting with｝, the connection between the address areas is always at the maximum inversion interval 11
This is a space of bit length. As a result, it is possible to extend the moving time of the laser beam during cutting while keeping the zero-run limit in the run-length limiting code.

As a further feature of the pattern p5, a specific bit for identifying a state (the first bit and the
The second, twelfth, and fourteenth bits adjacent to the “0” bit (bit) are all “0”. As a result, it is possible to prevent the 13th bit from being erroneously recognized as “1” due to a bit shift or the like, thereby preventing the state from being erroneously demodulated.

Note that the pattern of the postamble PA is not limited to the pattern p5 shown in this example. The number of zero runs satisfies the limit of the run length limit code used in the address information area ID, and the state information is 1 Or 2 as long as it has a pattern different from that of the address mark AM and includes "1" an odd number of times.

FIG. 24B shows a case where the next state is state 1 or state 2 (see FIG. 18B), and the end of the address information area ID ends with a space. In this case, the pattern p6 as shown in FIG.
{0000010010000000} is selected and the mark length is recorded. Next state is state 1 or state 2
When all the code sequences are connected to the pattern p6, the zero run is also limited to 2 to 10 at the connection. The first bit and the thirteenth bit of the pattern p6 are both "0". Also, the pattern p
By selecting 6, the end of the postamble PA,
That is, the end of the address area is always a space. As a result, a space is formed between the head and the end of each address area, thereby preventing a mark formation defect at the time of cutting the master disc and a data reading error due to the overlap of the address areas at the time of reproduction of the address area, between the address areas to be wobbled. be able to.

Further, the pattern of the VFO area arranged at the head of each address area is set to {000100010001000.
By using a continuous pattern signal starting with｝, the connection between the address areas is always at the maximum inversion interval 11
This is a space of bit length. As a result, it is possible to extend the moving time of the laser beam during cutting while keeping the zero-run limit in the run-length limiting code.

As a further feature of the pattern p6, a specific bit for identifying a state (the first bit and the 13th bit).
The second, twelfth, and fourteenth bits adjacent to the “0” bit (bit) are all “0”. As a result, it is possible to prevent the 13th bit from being erroneously recognized as “1” due to a bit shift or the like, thereby preventing the state from being erroneously demodulated.

Note that the pattern of the postamble PA is not limited to the pattern p6 shown in this example. The number of zero runs satisfies the limit of the run length limit code used in the address information area ID, and the state information is 1 Or 2 as long as it has a pattern different from the address mark AM and includes "1" an even number of times.

FIG. 24C shows a case where the next state is state 3 or state 4 (see FIG. 18B), and the end of the address information area ID ends with a mark 240. In this case, the pattern p as shown in FIG.
7 {1000010010000000} is selected and the mark length is recorded. When all the code sequences whose next state is state 3 or state 4 are connected to the pattern p7, the zero run is also limited to 2 to 10 at the connection portion. One bit of the pattern p7 is "1". Also, by selecting the pattern p7,
The end of the postamble PA, that is, the end of each address area is always a space.

As a result, the leading and trailing ends of each address area become spaces, and between the address areas where wobbles are arranged, mark formation defects during cutting of the master disc and data reading errors due to overlapping of the address areas during reproduction of the address areas. Can be prevented.

Further, the pattern of the VFO area arranged at the head of each address area is defined as $ 000100010001000.
By using a continuous pattern signal starting with｝, the connection between the address areas is always at the maximum inversion interval 11
This is a space of bit length. As a result, it is possible to extend the moving time of the laser beam during cutting while keeping the zero-run limit in the run-length limiting code.

The pattern of the postamble PA is not limited to the pattern p7 shown in this example. The number of zero runs satisfies the limit of the run length limit code used in the address information area ID, and the state information is three. Or 4 as long as it has a pattern different from that of the address mark AM and includes "1" an odd number of times.

FIG. 24D shows a case where the next state is state 3 or state 4 (see FIG. 18B), and the end of the address information area ID ends with a space. In this case, the pattern p8 as shown in FIG.
{1000000010000000} is selected and the mark length is recorded. Next state is state 3 or state 4
When all the code sequences are connected to the pattern p8, the zero run is also limited to 2 to 10 at the connection. The first bit of the pattern p8 is "1". By selecting the pattern p8, the end of the postamble, that is, the end of each address area always becomes a space. As a result, a space is formed between the head and the end of each address area, thereby preventing a mark formation defect at the time of cutting the master disc and a data reading error due to the overlap of the address areas at the time of reproduction of the address area between the address areas to be wobble. be able to.

Further, the pattern of the VFO area arranged at the head of each address area is set to $ 000100010001000.
By using a continuous pattern signal starting with｝, the connection between the address areas is always at the maximum inversion interval 11
This is a space of bit length. As a result, it is possible to extend the moving time of the laser beam during cutting while keeping the zero-run limit in the run-length limiting code.

Note that the pattern of the postamble PA is not limited to the pattern p8 shown in this example. The number of zero runs satisfies the limit of the run length limit code used in the address information area ID, and the state information is three. Or 4 as long as it has a pattern different from the address mark AM and includes "1" an even number of times.

FIGS. 24E to 24H show another example of the mark arrangement of the postamble PA when the state modulation code is used. 24E to 24H, each next state is a next state when the immediately preceding data is modulated. That is, the next state is obtained when the data at the end of the corresponding address information area ID is modulated.

FIG. 24E shows a case where the next state is state 1 or state 2 (see FIG. 18B), and the end of the address information area ID ends with a mark 240. In this case, the pattern P as shown in FIG.
9 [0000010000010001] is selected and the mark length is recorded. Next state is state 1 or state 2
Is connected to the pattern P9, the zero run is also limited to 2 to 10 at the connection portion. The first bit and the thirteenth bit of the pattern P9 are both "0". Also, the pattern P9
Is selected, the end of the postamble PA, that is, the end of the address area always becomes a space.

As a result, since the beginning and end of each address area are spaces, it is possible to prevent a mark formation defect from occurring between the address areas arranged in the fob during the cutting of the master disc, and to prevent the address area from being reproduced when the address area is reproduced. It is possible to prevent data reading errors due to overlapping areas.

Further, the pattern of the VFO area arranged at the head of each address area is defined as [000100010001000...
, The 4-bit mark at the end of each postamble is also VFO.
Can be used as

FIG. 24F shows a case where the next state is state 1 or state 2 (see FIG. 18B), and the end of the address information area ID ends with a space. In this case, the pattern P10 as shown in FIG.
[0001000100010001] is selected and the mark length is recorded. Next state is state 1 or state 2
Is connected to the pattern P10, the zero run is also limited to between 2 and 10 at the connection. 1st bit and 1 of pattern P10
The third bit is both "0". By selecting the pattern P10, the end of the postamble PA, that is, the end of the address area always becomes a space.

As a result, since the head and the end of each address area become spaces, it is possible to prevent a mark formation defect from occurring between the address areas arranged in the fob during the cutting of the master disc, and to prevent the address area from being reproduced during the reproduction of the address area. It is possible to prevent data reading errors due to overlapping areas.

Further, the pattern of the VFO area arranged at the head of each address area is defined as [000100010001000...
, The 4-bit mark at the end of each postamble is also VFO.
Can be used as

FIG. 24G shows a case where the next state is state 3 or state 4 (see FIG. 18B), and the end of the address information area ID ends with a mark 240. In this case, the pattern P as shown in FIG.
11 [1000100100010001] is selected and the mark length is recorded. When all the code sequences whose next state is state 3 or state 4 are connected to the pattern P11, the zero run is also 2 to 10 for the connection portion.
Are restricted between. The first bit of the pattern P11 is 1. By selecting the pattern P11, the end of the postamble PA, that is, the end of the address area always becomes a space.

As a result, since the head and the end of each address area become spaces, it is possible to prevent a mark formation defect from occurring between the address areas arranged in the fob when cutting the master disc, and to prevent the address area from being reproduced when the address area is reproduced. It is possible to prevent data reading errors due to overlapping areas.

Further, the pattern of the VFO area arranged at the head of each address area is defined as [000100010001000...
, The 4-bit mark at the end of each postamble is also VFO.
Can be used as

FIG. 24H shows a case where the next state is state 3 or state 4 (see FIG. 18B) and the end of the address information area ID ends with a space. In this case, a pattern P12 as shown in FIG.
[1000010000010001] is selected and the mark length is recorded. Next state is state 3 or state 4
Is connected to the pattern P12, the zero run is also limited to 2 to 10 at the connection portion. The first bit of the pattern P12 is "
In addition, by selecting the pattern P12, the end of the postamble PA, that is, the end of the address area always becomes a space.

As a result, since the head and the end of each address area become spaces, it is possible to prevent a mark formation defect from occurring between the address areas arranged in the fob during the cutting of the master disc, and to prevent the address area from being reproduced when the address area is reproduced. It is possible to prevent data reading errors due to overlapping areas.

Further, the pattern of the VFO area arranged at the head of each address area is defined as [000100010001000...
, The 4-bit mark at the end of each postamble is also VFO.
Can be used as

Here, the postamble PA described above is used.
The following shows an example of the arrangement of each pattern. As one example, FIG.
Postambles having patterns p5 to p8 shown in A to D are combined with postambles PA1 and PA2 shown in FIG.
What is necessary is just to use as PA3 and PA4. Alternatively, the postambles having the patterns p9 to p12 shown in FIGS.
2, PA3 and PA4 may be used.

The patterns p5 to p5 shown in FIGS.
The postamble having p8 is used for the postambles PA2 and PA4 in FIG. 20C, and the postamble having the patterns p9 to p12 shown in FIGS.
It may be used for C postambles PA1 and PA3.
At this time, if the address areas on the disk are arranged as shown in FIG. 21B, the address area between the address areas 213 and 214 where the cutting laser beam does not need to be shifted and the address area between the address areas 215 and 216 do not need to be shifted. , The end of the address areas 213 and 215 can be used as a VFO, and an 11-bit space can be obtained between the address areas 214 and 215 where the cutting laser beam needs to be shifted. Can be utilized. Further, at this time, by making the lengths of VFO1 and VFO3 longer than the lengths of VFO2 and VFO4, the first address areas 213 and 215 arranged in the wobble arrangement are arranged.
, The clock reproduction at the time can be stabilized.

(Embodiment 4) FIG. 25A shows a format of a recording sector 61 of an optical disc according to a fourth embodiment of the present invention. A header area 62 is provided at the beginning of the recording sector 61, and addressing information for reading address information is recorded in advance. After the header area 62, a gap area 63, a data recording area 64, a postamble 6
5, a guard data recording area 66 and a buffer area 67 follow in order. No data is recorded in the gap region 63, and is used for, for example, power control of a semiconductor laser used for data recording and reproduction. User data is recorded in the data recording area 64. Digital data is generated by adding redundant data such as an error correction code to the user data. The digital data is modulated by a predetermined run length limiting code and recorded in the data recording area 64 with a mark length.

The postamble 65 is a data recording area 64
Indicates the end of. The pattern of the postamble 65 is determined based on the modulation result of the data recording area 64. The postamble 65 includes information used when demodulating data, for example, like the state identification bit described in the second embodiment. The guard data recording area 66 is provided to suppress the influence of deterioration of the recording surface due to repeated recording of data in the same recording sector, and records dummy data that does not include specific information. Buffer area 6
Reference numeral 7 is provided to absorb fluctuations in the rotation of the optical disk and the like.

Data recording area 64, postamble 6
5 and the guard data area 66 are recorded by irradiating a light spot having a predetermined recording power to form an optical mark on the recording surface. Generally, by changing the crystal structure of the thin film on the surface of the recording surface to amorphous, the reflection characteristic of the mark portion is changed. As described above, since a relatively large power light spot is applied to data recording, a thermal load is applied to the recording surface, which causes deterioration of the recording surface.

In particular, in each recording sector, there is a difference in heat load at the boundary between the area where recording is performed and the area where recording is not performed. When data recording is repeatedly performed, the material of the recording film may move due to the difference in heat load, and the boundary portion may be deteriorated, making it difficult to read data correctly. Therefore, when using an optical disc whose recording surface can be deteriorated by repeated recording, necessary data is
It is not preferable to record near the boundary where such a difference in heat load occurs. Therefore, in the present embodiment, a guard data recording area 66 is provided to solve such a problem. In the guard data recording area 66, dummy data that gives a thermal load similar to the thermal load when recording the data recording area 64 or the postamble 65 is recorded. Data recording area 64 and postamble 65
When the ratio of the mark or space appearing in the data pattern is biased in either direction, the low frequency component of the pattern increases. Such an increase in the low-frequency component is not preferable because it changes the reproduction signal component in the servo band and affects the servo system. Therefore, it is desirable that the low frequency component of the pattern be as small as possible.
Modulation is often performed such that the total number of bits of the mark and the total number of bits of the space are as equal as possible.

Therefore, it is preferable that the pattern of the dummy data recorded in the guard data recording area 66 is also a pattern in which the total number of bits of the mark is equal to the total number of bits of the space. This is because the thermal load of the dummy data becomes substantially equal to the thermal load when recording the data recording area 64 and the postamble 65.

For example, a pattern in which a k-bit mark and a space are alternately repeated an even number of times can be used. Here, k is a natural number satisfying Tmin ≦ k ≦ Tmax. Tmin is the minimum inversion interval of the run length limited code, and Tmax is the maximum inversion interval.

Further, it is more preferable that the length of the guard data recording area 66 be an integer data byte, since the processing of the modulation circuit and the demodulation circuit is simplified.

FIG. 25B shows a modulation code (T) in which one data byte becomes 16 bits after modulation as described with reference to FIG. 18B.
This is an example of a pattern recorded in the guard data recording area 66 when (min = 3, Tmax = 11) is used. The pattern of this example is a pattern in which marks and spaces each having a length of 4 bits are alternately repeated, and has a total length of 16 × n bits (n is a natural number).

Although FIG. 25B shows an example in which the dummy data starts from the mark, it goes without saying that the pattern at the end of the postamble 65 may start with a space.

The thermal load of the pattern shown in FIG.
Since the total number of bits of the mark and the total number of bits of the space are equal, the data recording area 64 and the postamble 65
Is about the same as the heat load when recording. Therefore, it is possible to prevent deterioration of the recording film due to a difference in heat load.

Further, since this pattern satisfies the conditions of the minimum inversion interval and the maximum inversion interval of the modulation code (run length limiting code), it does not adversely affect the reproduction of the header area and the data area.

[0209]

As described above, the optical disk of the present invention records address information modulated by using address synchronization information and a run length limit code in the header area provided in each recording sector. Since the pattern of the address synchronization signal includes two patterns that are longer than the maximum inversion interval Tmax of the run length limit code by three bits or more, the reproduction signal of the address synchronization information is distinguished from the reproduction signal of other information, and False detection is less likely to occur. This makes it possible to stably perform bit synchronization for reproducing address information using address synchronization information without providing a sector mark in each recording sector.

[0210] The address synchronization information is recorded using first and second patterns that differ in either the physical shape or the optical characteristics of the recording surface of the optical disc. For example,
The first pattern is a projection (pit) physically formed on the recording surface of the optical disk, and the second pattern is a depression physically formed on the recording surface. Alternatively, the first pattern is a recording mark in which the reflection characteristic of the recording surface of the optical disk has been changed, and the second pattern is a space on the recording surface. Since the address synchronization information includes a first pattern having one (Tmax + 3) bit length or more and a second pattern having one (Tmax + 3) bit length or more, even when an error due to a bit shift or the like occurs. , Can be distinguished from other data modulated by the run length limited code.

By making the total bit length of the first pattern and the total bit length of the second pattern included in the header area equal, the low frequency component of the pattern can be reduced. This does not impair the stability of the servo system during reproduction of the header area.

By repeatedly recording the address information and the address synchronization information four times in the header area, the number of unreadable recording sectors of the address information on the high-density optical disc is reduced to within an allowable range, and the high-quality It is possible to provide a simple optical disk.

The header area of each recording sector on the optical disc of the present invention includes address information for identifying the position of the corresponding recording sector and address synchronization information for identifying the recording position of the address information and performing bit synchronization. And clock synchronization information for reproducing a clock signal. The address information includes a minimum inversion interval Tmin bit and a maximum inversion interval Tmax bit (where Tmax and Tmin are Tmax> T).
The clock synchronization information is modulated using d-bits (d is Tmi).
This is a continuous pattern in which marks and spaces of n ≦ d <Tmax (natural numbers satisfying Tmax) are alternately repeated. The address synchronization information includes two patterns whose inversion interval is (Tmax + 3) bits or more, whereby a reproduction signal of the address synchronization information is distinguished from a reproduction signal of other information. d
By reading a continuous pattern in which bit marks and spaces are alternately repeated, clock reproduction can be performed at high speed. By reading address synchronization information, bit synchronization for reproducing address information can be performed stably.

The optical disk of the present invention does not record a pattern (sector mark) consisting of a long mark for identifying the start of a recording sector at the beginning of each recording sector, thereby reducing the data overhead as a format. be able to. At the same time, as described above, the detection of the start of the recording sector and the reproduction of the clock can be performed simultaneously using the clock synchronization information.

[0215] In the optical disc of the present invention, each recording sector includes a header area and a postamble area provided at the end of the header area, and the postamble area corresponds to a modulation result of data in the header area. The pattern determined on the basis of this is recorded. Therefore, for example, when the data in the header area is modulated using a modulation code that changes the table based on the state, it is possible to include information for identifying the state in the postamble, and demodulate the data in the header area. Can be performed efficiently.

Further, in the optical disc according to the present invention,
Each recording sector includes a header area, a data recording area, and a postamble area provided at the end of the data recording area, and the postamble area is determined based on a modulation result of data in the data recording area. The recorded pattern is recorded. Therefore, for example, when the data of the data recording area is modulated using a modulation code that changes a table based on a state, the postamble area can include information for identifying the state, and similarly, In addition, demodulation of data in the data recording area can be performed efficiently.

The recording sector further includes a guard data recording area for recording dummy data after the postamble area. The guard data recording area is, for example,
It has a pattern in which a k-bit optical mark and a k-bit optical space are repeated. Where k is Tmi
It is a natural number satisfying n ≦ k ≦ Tmax. By providing such a guard data area, it is possible to prevent deterioration of the recording surface due to repeated recording, and to prevent the reliability of the recorded data from being impaired.

In the optical disc of the present invention, each recording sector has a header area, and the header area includes an address area having a postamble area at the end thereof.
The postamble area has a pattern in which non-pit data or space is arranged at the end. The header area has a plurality of address areas, and the VFO area provided at the head of each address area has a pattern in which non-pit data or space is recorded at the head. Alternatively, non-pit data or space having a Tmax bit length is provided between each address area. Thus, even when an address area is recorded between a land track and a groove track, it is easy to form a mark in a manufacturing process of an optical disc, and it is possible to prevent an error in reading information in the address area.

The optical disk apparatus according to the present invention comprises: means for reading a reproduction signal from an optical disk; address reproduction means for obtaining the address information from the reproduction signal; and detecting and detecting the continuous pattern of the clock synchronization information from the reproduction signal. A detection unit that outputs a signal; and an address reproduction permission unit that permits the address reproduction unit to read the address information based on the detection signal. As a result, even for an optical disk that does not include a sector mark (a pattern formed by a long mark for distinguishing the start of a recording sector) at the beginning of each recording sector, a continuous pattern of clock synchronization information is detected, thereby achieving a stable and stable operation. It is possible to efficiently reproduce address information. The conventional optical disk has both the sector mark and the clock synchronization information in the header area. According to the present invention, the sector mark is not required, so that the data recording area can be increased accordingly.

[0220] Also, the optical disk apparatus according to the present invention comprises a clock generating means for generating a clock signal from the reproduction signal, and the clock generating means based on the detection signal of the continuous pattern of the clock synchronization information. And clock reproduction permission means for permitting the generation operation. This makes it possible to reproduce a clock signal stably and efficiently by detecting a continuous pattern of clock synchronization information even on an optical disk that does not include a sector mark at the beginning of each recording sector.

The method for reproducing an optical disk according to the present invention comprises the steps of: extracting a reproduction signal from the optical disk; detecting the continuous pattern of the clock synchronization information from the reproduced signal; and detecting the address when the continuous pattern is detected. Permitting the reading of information, reading the address information from the reproduced signal in accordance with the permission, suspending the step of reading the address information for a predetermined period after the permission, and returning to the step of detecting the continuous pattern. And a step. As a result, the address information is read stably at power-on or immediately after the track jump even for an optical disk having a predetermined continuous pattern of clock synchronization information without including a sector mark at the beginning of each recording sector. It becomes possible.

Further, in the method for reproducing an optical disk according to the present invention, a step of extracting a reproduction signal from the optical disk, a step of detecting the continuous pattern of the clock synchronization information from the reproduced signal, and a step of detecting the continuous pattern Permission of the reproduction of the clock signal in the case, and reproducing the clock signal from the reproduction signal according to the permission. As a result, a sector mark is not recorded at the beginning of each recording sector in order to identify the start of the recording sector, and the optical disk on which clock synchronization information of a predetermined continuous pattern is recorded can also be recorded at power-on or immediately after a track jump. Clock signal can be stably reproduced.

The method of reproducing an optical disk according to the present invention comprises the steps of extracting a reproduction signal from the optical disk and determining a reproduction mode, wherein the address is first determined from the reproduction signal after power-on or after a track jump. Determining an initial mode during a period until the information is read, and a normal mode during a period from when the address information is read until the next track jump is generated; and Detecting a continuous pattern; a first permission step of permitting reading of the address information when the continuous pattern is detected in the initial mode; and reading the address information from the reproduction signal according to the permission. Generating a sector pulse when the address information is correctly read; A second permission step of permitting reading of the address information from the reproduced signal based on the sector pulse, and within a predetermined time after permission of any of the first and second permission steps. Stopping the reading of the address information when the address information cannot be read and returning to the reproduction mode determination step. As a result, the processing from when the power is turned on or after the track jump to when the address information is first reproduced, and
This makes it possible to switch between normal data reproduction processing and more efficient and reliable reading of the address information of each recording sector.

Also, by using the above-described optical disk of the present invention and the optical disk apparatus of the present invention or the optical disk of the present invention and the optical disk reproducing method of the present invention in combination, the recording density of the optical disk can be reduced to the mark length recording,
Even when the information is improved by using a method such as groove recording, the address information can be read more stably and efficiently.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating mark length recording and inter-mark recording.

FIG. 2A is a diagram showing a signal format of a recording sector of a conventional optical disc.

FIG. 2B is a diagram showing the contents of a header of a conventional optical disc.

FIG. 2C is a diagram showing a recording pattern of a sector mark of a conventional optical disc.

FIG. 2D is a diagram showing a recording pattern of an address mark of a conventional optical disc.

FIG. 3 is a diagram showing a modulation table of a (2, 7) modulation code.

FIG. 4 is a diagram showing an example of a reproduced signal waveform in a header of a conventional optical disc.

FIG. 5A is a diagram illustrating a configuration of an optical disc according to an embodiment of the present invention.

FIG. 5B is a diagram illustrating a configuration of an optical disc according to an embodiment of the present invention.

FIG. 5C is a diagram illustrating a configuration of an optical disc according to an embodiment of the present invention.

FIG. 6 is a diagram showing an example of a recording pattern of a VFO area of an embodiment of the optical disc according to the present invention.

FIG. 7A is a diagram showing an example of a recording pattern of an address mark of an optical disc according to an embodiment of the present invention.

FIG. 7B is a diagram showing an example of a recording pattern of an address mark of an optical disc according to an embodiment of the present invention.

FIG. 7C is a diagram showing an example of a recording pattern of an address mark of an optical disc according to an embodiment of the present invention.

FIG. 8A is a diagram showing an example of a recording pattern of an address mark of an optical disc according to an embodiment of the present invention.

FIG. 8B is a diagram showing an example of a recording pattern of an address mark of an optical disc according to an embodiment of the present invention.

FIG. 8C is a diagram showing an example of a recording pattern of an address mark of an optical disc according to an embodiment of the present invention.

FIG. 8D is a diagram showing an example of a recording pattern of an address mark of an optical disc according to an embodiment of the present invention.

FIG. 9 is a diagram showing an example of a recording pattern of an address mark of an optical disc according to an embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of an optical disk device according to one embodiment of the present invention.

11 is a block diagram showing an example of the internal configuration of the reproduction system shown in FIG.

FIG. 12A is a block diagram showing an example of an internal configuration of a VFO detection circuit according to one embodiment of the present invention.

FIG. 12B is a diagram showing a configuration of a VFO detection table according to one embodiment of the present invention.

FIG. 13 is a timing chart showing an example of waveforms of various signals used in the optical disc device according to one embodiment of the present invention.

FIG. 14 is a timing chart showing an example of waveforms of various signals used in the optical disc device according to one embodiment of the present invention.

FIG. 15 is a flowchart illustrating an example of processing after power-on of a system control system in the optical disc device according to an embodiment of the present invention.

FIG. 16 is a flowchart illustrating an example of processing of a system control system in the optical disc device according to one embodiment of the present invention.

FIG. 17A is a diagram showing a signal format of a recording sector of an optical disc according to an embodiment of the present invention.

FIG. 17B is a diagram showing a signal format of a header area of the optical disc according to one embodiment of the present invention.

FIG. 18A is a block diagram illustrating a configuration of a modulation circuit for a state modulation code according to an embodiment of the present invention.

FIG. 18B is a diagram showing an example of the contents of the conversion table shown in FIG. 18A.

FIG. 18C is a block diagram showing a configuration of a state modulation code demodulation circuit according to one embodiment of the present invention.

FIG. 19A is a diagram showing an example of a postamble recording pattern according to an embodiment of the present invention.

FIG. 19B is a diagram showing an example of a postamble recording pattern according to an embodiment of the present invention.

FIG. 20A is a diagram illustrating a configuration of an optical disc according to an embodiment of the present invention.

FIG. 20B is a diagram illustrating a configuration of an optical disc according to an embodiment of the present invention.

FIG. 20C is a diagram illustrating a configuration of an optical disc according to an embodiment of the present invention.

FIG. 21A is a schematic diagram showing an example of an arrangement of address areas in a header area of an optical disc in one embodiment of the present invention.

FIG. 21B is a schematic view showing an example of the arrangement of address areas in the header area of the optical disc in one embodiment of the present invention.

FIG. 21C is a diagram showing a connection portion between the address areas shown in FIGS. 21A and 21B.

FIG. 22A is a schematic diagram showing a case where a connection portion of an address area of an optical disc is a mark and the mark is ideally formed.

FIG. 22B is a schematic view showing a mark actually formed at a connection portion of an address area of the optical disc.

FIG. 23A is a diagram illustrating an operation in which a light spot reproduces a land track.

FIG. 23B is a diagram illustrating an operation of reproducing a land track by a light spot.

FIG. 24A is a diagram showing an example of a postamble.

FIG. 24B is a diagram showing an example of a postamble.

FIG. 24C is a diagram showing an example of a postamble.

FIG. 24D is a diagram illustrating an example of a postamble.

FIG. 24E is a diagram showing an example of a postamble.

FIG. 24F is a diagram showing an example of a postamble.

FIG. 24G is a diagram showing an example of a postamble.

FIG. 24H is a diagram showing an example of a postamble.

FIG. 25A is a diagram showing a signal format of a recording sector of an optical disc according to an embodiment of the present invention.

FIG. 25B is a diagram showing an example of a pattern recorded in a guard data recording area according to an embodiment of the present invention.

[Explanation of symbols]

 1a Optical disc 1b Track 1c Recording sector 2 Header area 3 Gap area 4 Data recording area 5 Buffer area

Claims (5)

[Claims] 1. An optical disk having a plurality of tracks divided into a plurality of recording sectors, each recording sector including a header area, the header area including a plurality of address areas, and Each of them records address information for identifying the position of the corresponding recording sector, address synchronization information for identifying the recording position of the address information and performing bit synchronization, and clock synchronization information for reproducing a clock signal. The address information is modulated using a run length limiting code having a minimum inversion interval Tmin bit and a maximum inversion interval Tmax bit (Tmax and Tmin are natural numbers satisfying Tmax> Tmin), and the clock synchronization information is , D bits (d is Tmin ≦ d <Tm
(a natural number that satisfies ax) is a continuous pattern that alternately repeats marks and spaces. The address synchronization information has an inversion interval of (Tmax + 3)
An optical disc including two patterns of bits or more. 2. The address synchronization information and the clock synchronization information are recorded using first and second patterns having different physical shapes and optical characteristics of the recording surface of the optical disk. The synchronization information includes a first pattern having a length of (Tmax + 3) bits or more and a second pattern having a length of (Tmax + 3) bits or more.
The optical disc according to claim 1, comprising: 3. The optical disc according to claim 1, wherein the minimum inversion interval Tmin is 3, the maximum inversion interval Tmax is 11, and the d is 3. 4. The optical disc according to claim 1, wherein the minimum inversion interval Tmin is 3, the maximum inversion interval Tmax is 11, and the d is 4. 5. The optical disk according to claim 1, wherein the header area repeatedly records the clock synchronization information, the address information, and the address synchronization information four times.