JP2822252B2 - Recording method, recording medium, and recording / reproducing device - Google Patents

Description

The present invention relates to a recording method, a recording medium, and a recording / reproducing apparatus suitable for application to, for example, a magneto-optical disk.

[Summary of the Invention] The present invention is a recording method suitable for application to a magneto-optical disk or the like, in which data modulated by a modulation method that satisfies a predetermined modulation rule by inserting connection bits between continuous modulated data. In the recording method of (1), the control information is recorded by the displacement in the width direction of the track, and the modulation data is recorded so that the displacement point in the width direction of the track coincides with the recording area of the connection bit. The influence of displacement in the width direction during reading is eliminated.

The present invention also provides a recording medium suitable for a magneto-optical disk or the like, in which a track whose width is displaced at a repetition cycle corresponding to a modulation unit length including connection bits is provided, and at a predetermined multiple of a maximum inversion interval in the modulation method, Tracks in a synchronous section displaced longer than the repetition cycle are provided to enable good signal reproduction.

Further, the present invention is a recording medium on which data modulated by a modulation method satisfying a predetermined modulation rule by inserting connection bits between continuous modulation data is recorded, wherein control information is recorded by a track width displacement. At the same time, the modulation data is recorded such that the recording area of the connection bit and the displacement point in the track width direction coincide with each other.

Still further, the present invention relates to a recording / reproducing apparatus suitable for a recording / reproducing apparatus for a magneto-optical disk, etc. Detection of pits formed by modulation at a repetition cycle in accordance with the modulation unit length is performed by a common circuit. For example, the circuit can be shared by a magneto-optical disk and a compact disk for digital audio. Things.

[Conventional technology]

In an optical recording medium, for example, a magneto-optical disk, a guide groove for tracking is previously formed in a spiral or concentric shape on the disk, and the guide groove (so-called groove) formed in advance or a land portion between the grooves is formed. A recording track has been developed in which data is recorded and reproduced using the magneto-optical effect on the recording track along the track direction. Such a recording medium magneto-optically records and reproduces data while optically detecting the guide groove and applying tracking servo.

By the way, in a recording medium having such a groove as a recording track, the groove is previously displaced in a width direction at a predetermined interval at the time of molding a disc, and control information such as address information and synchronization information is recorded by the displacement in the width direction. It is proposed to put. For example, as shown in FIG. 4, a groove a provided along the scanning direction of the optical head is
The address information is slightly displaced in the width direction orthogonal to the scanning direction at intervals based on digitized data of the address information or at intervals based on a synchronization signal necessary for reproduction. When data is recorded in the groove a, the polarity in the groove is changed by the magneto-optical effect regardless of the displacement in the width direction to record various data. The signal recorded in the groove by this magneto-optical effect is hereinafter referred to as MO signal. By doing so, control information such as address information and synchronization information is efficiently recorded.

[Problems to be solved by the invention]

However, when the groove is displaced in the width direction in this manner, there is a possibility that the edge portion e, which is the point of the groove being displaced in the width direction, may adversely affect the reproduction of the MO signal recorded in the groove. That is, for example, when the edge portion of the MO signal and the edge portion e due to the displacement in the width direction are close to each other, there is some influence such that it is difficult to accurately determine the edge portion of the MO signal.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a displacement in a groove width direction from adversely affecting recorded data reproduction.

[Means for solving the problem]

According to the recording method of the present invention, in a recording method of data modulated by a modulation method that satisfies a predetermined modulation rule by inserting a connection bit between continuous modulation data, control information is recorded by displacement of a track in a width direction, The modulation data is recorded such that the displacement point in the width direction of the track coincides with the recording area of the connection bit.

Further, the recording medium of the first invention has a track whose width is displaced at a repetition period corresponding to a modulation unit length including connection bits, and has a width longer than the repetition period at a predetermined multiple of a maximum inversion interval in the modulation method. A track in a displaced synchronous section is provided.

A recording medium according to a second aspect of the present invention is a recording medium on which data modulated by a modulation method satisfying a predetermined modulation rule by inserting connection bits between continuous modulated data is recorded. , Control information is recorded, and the modulation data is recorded such that the recording area of the connection bit coincides with the displacement point in the width direction of the track.

Further, the recording / reproducing apparatus of the present invention detects the width displacement of the track whose width is displaced at the repetition cycle corresponding to the modulation unit length including the connection bit, and modulates the track at the repetition cycle corresponding to the modulation unit length including the connection bit. The detected pits are detected by a common circuit.

[Action]

According to the recording method of the present invention, the connection bits recorded on the track coincide with the width-direction displacement point, and the connection bits do not need to determine the recording information. And there is no influence of the displacement in the width direction during reproduction.

Further, according to the recording medium of the first aspect of the present invention, by providing the track of the synchronous section which is displaced longer than the repetition period at a predetermined multiple of the maximum inversion interval in the modulation method, a good signal can be detected by detecting the synchronous section track. Can be played.

Further, according to the recording medium of the second invention, the connection bits recorded on the track coincide with the displacement points in the width direction. Since the connection bits do not need to determine the recorded information, the connection bits near the displacement points in the width direction can be used. It is not necessary to determine the recorded information, and there is no influence of the displacement in the width direction when reproducing the recording medium.

Further, according to the recording / reproducing apparatus of the present invention, the width of the track and the formation of the pit are adjusted to the same modulation unit length including the connection bit, whereby the pit and the recording medium having the track displaced in the width direction are formed. It is possible to share the circuit of the recording / reproducing apparatus with the formed recording medium.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows a recording track formation state of a magneto-optical disk formed according to an embodiment of the present invention. The magneto-optical disk of this embodiment in which the tracks are formed is formed by forming a perpendicular magnetization film having a magneto-optical effect on a transparent substrate, and a guide groove for tracking is formed on the magneto-optical disk. ) Are formed in advance in a spiral or concentric manner, and these grooves are used as recording tracks (the tracks are shown as straight lines in FIG. 1). In this case, in this example, various data as control information is recorded in advance in the groove at the time of forming the disk by displacement in the width direction. This control information recording format is a so-called CD for recording digital audio signals and the like.
(Compact disk) recording format. That is, in the general CD format, one block (one sector) serving as an information recording unit includes 98 frames from the 0th frame to the 97th frame. FIG. 2 shows the structure of each frame. One frame is 588 times the channel clock period T (588T), and one frame contains each of a frame synchronization signal, a subcode, and data (including parity). A recording area is provided. At the beginning of one frame, a frame synchronization signal of 24T (24 channel bits) and a subcode area of 14T are provided, and these are connected via connection bits of 3T, respectively. Data and parity of 32 symbols (32 bytes) are arranged by being modulated by a so-called EFM (8-14 modulation) method.

In the data modulation by the EFM method, an original symbol converts 8-bit data into a 14-bit pattern, and 3 symbols are inserted between each symbol so that a connection state between the 14-bit patterns satisfies a predetermined condition. Insert connection bits (merging bits) of bits. As the three connection bits, four patterns of 000 100 010 001 are prepared, and one of the patterns is selected according to the preceding and following data. The DC component of the recording signal is controlled by inserting the connection bit, and the connection bit itself does not contain information.

Here, returning to the description of the magneto-optical disk according to the embodiment of the present invention, data modulated by the EFM method according to the above-described CD format is recorded on the groove provided on the magneto-optical disk of the present embodiment. In this case, one block (one sector) is divided into 10 frames from the 0th frame to the 99th frame.
0 frame, 9 frames from the 1st frame to the 98th frame
Data is recorded in 8 frames, and the 0th frame and the 99th frame are used as recording areas for address signals and synchronization signals in block units. From the first frame to the 98th frame, the data and parity recorded subsequent to the frame synchronization signal area, the subcode area, and the connection bits before and after the frame synchronization signal area consist of 32 symbols, each symbol being a 14-bit pattern. And 3 connection bits.

In the present example, the first to 98th frames for recording this data are preliminarily displaced in the width direction by (22T × 2 + 17T × 32) at each frame cycle, as shown in FIG. Keep it. In this case, the displacement in the width direction at a period of 22T is information as a frame synchronization signal,
The displacement in the width direction due to the period of 17T is information for clock generation and synchronization pull-in. And this groove (1)
When recording data modulated by the EFM method by the magneto-optical effect, the frame synchronization signal, the sub-code, and the connection bits before and after the sub-code are recorded at a position where the first 22T is repeated twice. In this case, as the frame synchronization signal, for example, a signal in which 11T continues twice is recorded as in the case of the frame synchronization signal of a CD. Incidentally, 11T is the maximum inversion interval T _MAX of the EFM method. Then, in the data and parity recording area of 32 symbols, the displacement point (edge) (1a) of the groove (1) whose width is displaced every 17T matches the data and parity connection bit recording area (1b). Record the data. At this time, for example, an edge (1a) is set at a substantially central portion of the connection bit recording area (1b) where three bits are recorded.

Next, the configuration of a recording / reproducing apparatus for reading data recorded in the groove (1) thus formed will be described.
As shown in FIG. The recording / reproducing apparatus shown in FIG. 3 is capable of reproducing a magneto-optical disk having grooves (1) formed thereon and reproducing a CD having pits formed as tracks (or a CD-ROM having a similar format). In FIG. 3, (11) indicates that the data recorded due to the physical change of the track (pit formation and groove width displacement) is RF.
A terminal that is read and supplied as a (high frequency) signal.
(12) MO recorded in the groove by magneto-optical effect
A terminal from which a signal is read and supplied. A signal supplied to each terminal (11) and (12) is supplied to first and second fixed contacts (31) and (32) of a changeover switch (3). I do. Switching of the changeover switch (3) is controlled by a changeover control signal supplied to a changeover control signal input terminal (20) together with a changeover switch (4) described later. Then, the RF signal or the MO signal obtained at the movable contact (33) of the changeover switch (3) is supplied to the binarization circuit (13), and the RF signal and the MO signal are set high by the binarization circuit (13). It is converted into binary data of a level signal “1” or a low level signal “0”. Then, the binary data output from the binarization circuit (13) is supplied to a synchronization detection circuit (14), a demodulation circuit (16), and a PLL circuit (18). The synchronization detection circuit (14) detects a frame synchronization signal recorded at the head of each frame based on a clock supplied from the PLL circuit (18), and outputs the detected synchronization signal to a disk rotation control circuit ( 15) and apply rotation speed servo.

The demodulation circuit (16) demodulates data recorded in each frame based on a clock supplied from the PLL circuit (18), and supplies the demodulated data to an error correction circuit (17).

Then, the PLL circuit (18) generates a 4.3218 MHz clock based on the reproduced data output from the binarization circuit (13), and switches the output clock via the 1/2 frequency divider (19). The output clock is supplied to a first fixed contact (41) of the switch (4) and the output clock is supplied to a second fixed contact (42) of the direct changeover switch (4). Then, a signal obtained at the movable contact (43) of the changeover switch (4) is supplied to the synchronization detection circuit (14). Further, the output clock of the PLL circuit (18) is supplied directly to the demodulation circuit (16).

The switching control signal obtained at the switching control signal input terminal (20) includes the two changeover switches (3) and (4) when accessing (recording and reproducing) the magneto-optical disk on which the groove is formed. Both the movable contacts (33) and (43) are the first
A signal to be connected to the fixed contacts (31) and (41) is supplied. When reproducing recorded data (MO signal) from a magneto-optical disk in which a groove is formed, both changeover switches (3),
(4) Both supply switching control signals for connecting the movable contacts (33) and (43) to the second fixed contacts (32) and (42).
When playing back a CD having pits formed thereon, the changeover switch (3) is connected to the first fixed contact (31).
A switching control signal for connecting the changeover switch (4) to the second fixed contact (42) is supplied.

Next, the operation of the recording / reproducing apparatus shown in FIG. 3 will be described. First, the case where recording and reproduction are performed on a magneto-optical disk having a groove (1) as shown in FIG. 1 will be described. When recording data on this magneto-optical disk, the changeover switch (3) is operated by the above-described changeover control signal. In both cases (4) and (4), the movable contacts (33) and (43) are connected to the first fixed contacts (31) and (41), and the first 22T of each frame recorded by the displacement in the groove width direction is performed twice. Detect the next part. That is, the synchronization detection circuit (14) includes the PLL
Since the 4.3218 MHz clock output from the circuit (18) is supplied by dividing the frequency by 1/2, the frame synchronization of 22T (22T is twice the frame synchronization signal 11T of the CD format) recorded by the displacement of the groove width Signal detection is a synchronous detection circuit (14)
And the disk rotation can be synchronized. In this state, EF
Data modulated by the M system is recorded as an MO signal (the recording system circuit is omitted). In this case, in the data and parity recording area of each frame, as shown in FIG.
The data is recorded so that the width-direction displacement point (edge) (1a) of the groove (1), which is displaced every time, matches the connection bit recording area (1b) for data and parity.

Then, at the time of reproduction of the magneto-optical disk, as in the case of recording, first, a frame synchronization signal of 22T recorded by the width displacement of the groove is detected and access is performed, and then the changeover switch (3 ) And (4), the movable contacts (33) and (43) are replaced with the second fixed contacts (32) and (4).
Connect to 2) to detect and reproduce the 11T frame synchronization signal recorded as the MO signal. In this case, the PLL circuit (1
Since the 4.3218 MHz clock output by 8) is supplied to the synchronization detection circuit (14) as it is, it is possible to detect a frame synchronization signal of 11T which is twice as large as 22T.

When reproducing a CD on which pits are formed, the changeover switch (3) is operated by the changeover control signal described above.
Is connected to the first fixed contact (31) and the changeover switch (4) is connected to the second fixed contact (42).
The 4.3218 MHz clock output from the PLL circuit (18) is supplied to the synchronization detection circuit (14) as it is, and an 11T frame synchronization signal formed as a pit is detected and reproduced.

As described above, according to the present example, as the recording / reproducing apparatus, the magneto-optical disk on which the groove was formed and the pit were formed.
Circuits can be shared with discs such as CDs. in this case,
The frame synchronization signal recorded by the displacement in the width direction of the groove has a period of 22T, which is an integral multiple of the frame synchronization signal (11T) of the signal modulated by the EFM method, so that only the switching of the frequency divider (19) is required. Synchronization can be easily detected. Also,
In the data and parity recording area of each frame formed in the groove of the magneto-optical disk, the groove is displaced in the width direction of the symbol every 17T, so that the recording data can be recorded in the unit of one symbol (one byte). You can look for it. Since the period (22T) of the frame synchronization signal is longer than the displacement in the width direction every 17T, the detection of the frame synchronization signal can be reliably performed. Furthermore, since the connection bit portion of the data and parity recording area of each frame is set to the position aligned with the displacement point in the groove width direction, the displacement point in the groove width direction may adversely affect the recorded data (MO signal) during reproduction. And good data reproduction can be performed. In other words, the connection bit part controls the DC component,
The connection bit itself contains no information, the 14-bit data recording portion does not overlap the width direction displacement point, and the width direction displacement does not affect data reproduction.

In the above-described embodiment, the so-called groove recording in which data recording on the magneto-optical disk is set in a groove is performed. However, the so-called land recording in which data recording is performed on a land portion between adjacent grooves is performed. Is also good. Further, in the above-described embodiment, the edge is almost at the center of the connection bit recording area where three bits are recorded. However, any one of the connection bit recording areas may coincide with the edge. Further, the present invention can be applied to various recording media such as, for example, organic dye-based optical disks, various write-once disks, overwritable disks, optical cards, and magneto-optical cards, in addition to the magneto-optical disks shown in the above embodiments. Furthermore, the present invention is not limited to the above-described embodiment, but may take various other configurations.

〔The invention's effect〕

According to the recording method of the present invention, the connection bit recorded on the track becomes the displacement point in the width direction, and since this connection bit does not need to determine the recording information, it is necessary to determine the recording information near the displacement point in the width direction. As a result, good reproduction without the influence of the displacement in the width direction can be performed during data reproduction.

Further, according to the recording medium of the present invention, by providing the track of the synchronous section which is displaced longer than the repetition cycle at a predetermined multiple of the maximum inversion interval in the modulation method, the synchronous section track can be reliably detected, and the synchronous section can be detected. Good signal reproduction can be performed by detecting the section track.

Further, according to the recording medium of the second invention, the connection bits recorded on the track coincide with the displacement points in the width direction. Since the connection bits do not need to determine the recorded information, the connection bits near the displacement points in the width direction can be used. It is not necessary to determine the recorded information, and there is no influence of the displacement in the width direction when reproducing the recording medium.

Further, according to the recording / reproducing apparatus of the present invention, the width of the track and the formation of the pit are adjusted to the same modulation unit length including the connection bit, whereby the pit and the recording medium having the track displaced in the width direction are formed. It is possible to share the circuit of the recording / reproducing apparatus with the formed recording medium.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a track forming state according to one embodiment of the present invention, FIG. 2 is an explanatory diagram showing a modulation state by the EFM system, and FIG. 3 shows a circuit configuration of a recording / reproducing apparatus according to one embodiment. FIG. 4 is a schematic diagram showing an example of a conventional recording medium. (1) is a groove, (1a) is an edge (width direction displacement point),
(1b) is a connection bit, (14) is a synchronization detection circuit, (16) is a demodulation circuit, and (18) is a PLL circuit.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 11/10 576 G11B 11/10 576A

Claims (4)

(57) [Claims] 1. A method of recording data modulated by a modulation method satisfying a predetermined modulation rule by inserting a connection bit between successive modulation data, wherein control information is recorded by a displacement in a track width direction. And a recording method for recording the modulation data such that a displacement point in the width direction of the track coincides with a recording area of the connection bit. 2. A synchronous section whose width is displaced at a repetition cycle corresponding to a modulation unit length including a connection bit and which is longer than the repetition cycle at a predetermined multiple of a maximum inversion interval in the modulation method. A recording medium comprising: a track; 3. A recording medium on which data modulated by a modulation method satisfying a predetermined modulation rule by inserting connection bits between continuous modulation data is recorded, wherein control information is recorded by a displacement in a track width direction. And a recording medium on which the modulated data is recorded such that the recording area of the connection bit coincides with the displacement point in the width direction of the track. 4. A method of detecting a width displacement of a track whose width is displaced at a repetition cycle corresponding to a modulation unit length including a connection bit, and detecting a pit modulated by a repetition cycle corresponding to a modulation unit length including a connection bit. A recording / reproducing apparatus, wherein the detection is performed by a common circuit.