JP2001297446A - Recording method, reproducing method and recording medium of information signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the conventional problem that the misjudgment of a prepit increases and conversely a error rate deteriorates for a recording signal when considering the interference of the prepit and a recording information signal because a prepit not adjacent to synchronous information interferes directly with the recording signal. SOLUTION: From the innermost periphery to the outermost periphery, a groove part is formed concentrically or spirally, and one side or both sides of the groove part are continuously formed with a wobble. Besides, a land part exists between adjacent groove parts. When an information signal is recorded in the groove part of the optical disk in which supplementary information is previously recorded in the land part at prescribed intervals as a prepit, a margin bit MB is inserted and recorded in the information signal so that the margin bit MB of a prescribed bit pattern is recorded at a position adjacent to the prepit of the groove part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an information signal recording method,
The present invention relates to a reproducing method and a recording medium, and more particularly to an information signal recording method for recording an information signal at a high density on a recording medium such as an optical disk, a reproducing method for reproducing, and a recording medium.

[0002]

2. Description of the Related Art Conventionally, pre-pit information is recorded in advance, and as a recording medium on which information can be rewritten based on the pre-pit information, a DVD-R (DVD-Recordable) is used.
e), DVD-RW (DVD-Rewritable) is known. Hereinafter, the relationship between prepits and recording signals of an optical disc based on the DVD-RW standard will be described as an example.

As described in Japanese Patent Application Laid-Open No. 10-293926, an optical disk of the above-mentioned standard has, for example, a spiral groove portion or land portion from the innermost periphery to the outermost periphery. One or both sides of the groove portion are continuously formed with a wobble, and a land portion exists between adjacent groove portions in the radial direction of the disk. Auxiliary information is previously stored in the land portion as pre-pits. Has been recorded. For this optical disc, an information signal is recorded in a groove portion.

Further, at the time of recording on the optical disk, reflected light obtained by irradiating the optical disk with a light beam is received by a well-known two-segment photodetector, and the obtained two light-receiving signals are subjected to a well-known push-pull method. The auxiliary information is acquired by detecting the pre-pit signal, and a wobble signal is extracted from the groove to extract a recording clock signal synchronized with the rotation of the optical disk. Further, based on the difference signal obtained by the push-pull method, the information beam is recorded by causing the light beam spot to follow and scan the groove portion.

The information signal to be recorded has a unit length T corresponding to a pit interval defined by a recording format.
Is recorded in units of 1488 times the sync frame. This sync frame is defined so that synchronization information Sync having a length of 14T from the beginning is provided. On the other hand, the auxiliary information recorded by the pre-pits is located in one sync frame of the recording signal recorded in the groove, in the land adjacent to the recording position of the synchronization information Sync, and at the top of the wobble. The pre-pit recording cycle is 2 sync frames.

That is, the synchronization information Sync of the sync frame of the information signal to be recorded is such that the pre-pit can be accommodated.
The data is encoded and recorded in synchronization with the recording clock signal. In addition to the position adjacent to the above-mentioned synchronization information Sync, the pre-pit may also exist at the vertex of another wobble adjacent to the recording information following the synchronization information Sync, and is used for information such as a physical address. are doing.

[0007]

In the conventional information signal recording method described above, when the interference between the pre-pit and the recording information signal is considered, the pre-pit Sync at the head of the pre-pit is 14T from the head of the sync frame of the recording signal. By synchronizing with the center of the flat synchronization information Sync recording period, mutual interference is reduced.

However, the other pre-pits directly interfere with the random recording signal, causing the pre-pits to have a reduced level and a phase shift.
False discrimination increases, and as a result, correct recording or reproduction cannot be performed. Conversely, noise is superimposed on a recording signal, so that an error rate deteriorates. This tendency becomes more conspicuous as the recording density increases, so a method of reducing mutual interference has been desired.

The present invention has been made in view of the above points, and has as its object to provide an information signal recording method, a reproducing method, and a recording medium capable of reducing interference between a recording signal and a prepit.

[0010]

According to the present invention, in order to achieve the above object, a concentric or spiral groove or land is formed from the innermost circumference to the outermost circumference, and the groove or land is formed. One or both sides of the land portion are formed with a continuous wobble, and a land portion or a groove portion exists between adjacent groove portions or the land portions, and auxiliary information is pre-pitted in the land portion or the groove portion in advance. In an information signal recording method for recording an information signal in a groove or a land of a recording medium recorded at a predetermined interval, a margin bit of a predetermined bit pattern is provided at a position adjacent to a prepit in the groove or the land. It is characterized in that a margin bit is inserted into an information signal for recording. In the present invention, during the period including the position of the pre-pit,
It is possible to record a margin bit which does not affect the reading of the prepit.

In order to achieve the above object, the recording medium of the present invention has a groove or land formed concentrically or spirally from the innermost periphery to the outermost periphery, and the groove or land is formed. One or both sides of the land portion are formed with a continuous wobble, and a land portion or a groove portion exists between adjacent groove portions or the land portions, and auxiliary information is pre-pitted in the land portion or the groove portion in advance. In a recording medium in which an information signal is recorded in a groove or a land, a margin bit of a predetermined bit pattern is recorded at a position adjacent to a prepit in the groove or the land. It is characterized by the following. According to the present invention, it is possible to provide a recording medium in which margin bits that do not affect reading of prepits are recorded during a period including the position of prepits.

According to the information signal reproducing method of the present invention, in order to achieve the above object, a concentric or spiral groove or land is formed from the innermost periphery to the outermost periphery, and the groove is formed. One or both sides of the section or land are formed with a continuous wobble, and a land or groove exists between adjacent grooves or lands, and the auxiliary information is provided in advance in the land or groove. Are recorded at predetermined intervals as pre-pits, and information is recorded from a recording medium in which margin bits are inserted into an information signal and recorded in a groove or land so that margin bits of a predetermined bit pattern are adjacent to the pre-pits. In an information signal reproducing method for reproducing a signal, a pre-pit signal included in a reproduced signal from a recording medium is detected. Based on the pre-pit signal obtained by, to determine the position of the margin bits, ignoring the reproduced signal from the position of the margin bit, and performs the reproduction of the information signal.

According to the present invention, since the margin bits which do not affect the reading of the pre-pits are reproduced during the period including the position of the pre-pits, the original information signal can be reproduced by ignoring the margin bits.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the positional relationship between prepits and recording signals in an embodiment of an information signal recording method according to the present invention. In this embodiment, a groove portion is formed concentrically or spirally from the innermost periphery to the outermost periphery, and one or both sides of the groove portion are continuously formed with undulations (wobbles). A land is present between adjacent groove portions in the disk radial direction. Auxiliary information is recorded in the land portion in advance as prepits, and an information signal is applied to an optical disk recorded in the groove portion.

In this embodiment, this optical disc is
As shown in FIG. 1B, a margin bit MB is inserted into an information signal at the position of the groove adjacent to the pre-pit recording position shown in FIG. Here, the margin bit MB is obtained before the NRZI conversion.
There are a number of consecutive "0" s between the first bit Pa and the last bit Pb, and the total number of bits is Nm, which obeys the run length restriction rule (d, k). Note that the run-length restriction rule (d, k) is a rule in which between "1" and "1", "0" s are continuous at a minimum of d and up to k at a maximum.

As shown in FIG. 1B, immediately before the margin bit MB, the number of "0" continues Nf, and immediately after the margin bit MB, the number of "0" is Nb. Continuous. Further, as shown in FIG. 1A, the number of bits from the leading edge of the pre-pit to the insertion position of the margin bit MB is Ns.

As can be seen from FIGS. 1A and 1B,
In the central section of the margin bit MB adjacent to the pre-pit, the sign inversion is not performed, so that the influence of the recording signal on the pre-pit is greatly reduced, and conversely, the influence of the pre-pit on the recording signal (information portion) is also reduced. Bit MB
Is naturally reduced because the distance is increased by the insertion. In addition,
First bit Pa and last bit Pb of margin bit MB
Is appropriately determined by an encoder in the recording apparatus, as described later.

FIG. 2 is a block diagram showing an example of an optical disk apparatus to which the information signal recording method according to the present invention is applied. In FIG. 1, an optical head 11 has a light source, an optical system such as an objective lens, a photodetector, and the like. When recording, a laser drive signal based on recording information data supplied from a laser drive circuit 12 is provided. In accordance with the above, the output power of the light beam from the light source is changed, and the light beam is applied to the information recording surface of the optical disc (not shown) to record the record information data. At the time of reproduction, the optical disk is irradiated with a light beam at a fixed output power (reading power), and the reflected light is received by a photodetector in the optical head 11.

The optical head 11 receives the reflected light of the light beam irradiated on the information recording surface of the optical disk from the information recording surface by a photodetector in the optical head 11 and converts the light into an electric signal. For example, by performing arithmetic processing based on the radial push-pull method, a detection signal carrying a wobble signal of prepits and grooves, recording information data, and the like is generated, and output to the reproduction amplifier 13.

The reproduction amplifier 13 amplifies the pre-pit signal from the land portion and the detection signal carrying the wobble signal of the groove portion, which are output from the optical head 11, and generates an information signal including the pre-pit signal and the wobble signal to generate a recording clock signal. In addition to supplying the amplified signal to the decoder 14, an amplified signal corresponding to the recorded information data is output to the decoder 15 during reproduction. The decoder 15 performs 8/16 demodulation and deinterleaving on the input amplified signal to decode the input amplified signal to generate a demodulated signal, and outputs the demodulated signal to the central processing unit (CPU) 16. .

On the other hand, the recording clock signal generator 14 calculates the maximum wobble signal from the composite signal in which the pre-pit signal is superimposed at a predetermined position (for example, the maximum amplitude position) of the wobble signal included in the information signal supplied from the reproduction amplifier 13. The pre-pit signal is detected and supplied to the pre-pit decoder 17 by comparing with a level larger than the amplitude value, and a wobble signal is extracted by binarizing the composite signal. A clock signal is generated and supplied to the encoder 18, and a rotation control signal is generated based on a difference signal between the recording clock signal and the reference clock signal, and is output to a motor drive system (not shown).

The pre-pit decoder 17 decodes auxiliary information from the supplied pre-pit detection signal,
Output to The CPU 16 performs an interface operation on the recording information data transmitted from a host computer or the like (not shown) so as to capture the recording information data into the recording device, and outputs the input recording information data to the encoder 18.

The encoder 18 performs ECC processing, 8/16 modulation processing and scramble processing using the recording clock signal supplied from the recording clock signal generator 14 as a timing signal, generates a modulation signal, and generates a power control circuit. 19 is output. Further, the encoder 18 performs a process of inserting a margin bit generated as described later into the recording information data based on the pre-pit position information supplied from the recording clock signal generator 14.

The power control circuit 19 converts the waveform of the modulated signal based on the recording clock signal supplied from the recording clock signal generator 14 in order to improve the shape of the recording pits formed on the optical disk. A so-called write strategy process) is performed, and is output to the laser drive circuit 12 as a recording signal. The laser drive circuit 12 includes the optical head 1
1 drives a light source, and outputs a laser drive signal for emitting a light beam with an emission power according to the supplied recording signal. During recording, the CPU 16 acquires address information from the auxiliary information supplied from the pre-pit decoder 17, and controls the entire data recording apparatus so as to record the record information data at a position on the optical disk corresponding to the address information. .

Here, in the present embodiment, the encoder 1
8 inserts a margin bit into the information signal (recording data). FIG. 3 shows an internal block diagram of an encoder for realizing one embodiment of the information recording method according to the present invention. 2, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. 3, the encoder 18 includes a code modulation block 181, a margin bit insertion block 182, and an NRZI converter 183.

The code modulation block 181 and N
The RZI converter 183 is configured in a conventional encoder. The present embodiment is characterized in that a margin bit insertion block 182 is provided between them. The pre-pit position information detected in the recording clock signal generator 14 is supplied to the margin bit insertion block 182, and the recording signal input from the code modulation block 181 based on the pre-pit position information is added to the margin bit insertion block 182.
According to the flowchart shown in FIG.
And insert the appropriate margin bits.

Next, a method of generating margin bits will be described with reference to the flowchart of FIG. In determining the leading bit Pa and the trailing bit Pb of the margin bits, (1) observe the run length restriction rule (d, k);
(2) DSV control for appropriately controlling the DC level is used as much as possible. (3) Inversion is performed as little as possible so as not to affect land pre-pits (LPP). To be satisfied.

That is, in the margin bit insertion block 182 in the encoder 18, first, the number Nf of consecutive “0” immediately before the margin bit of the information signal is smaller than d and the consecutive “0” immediately after the margin bit. The number Nb of d
It is determined whether it is smaller (step 101), and Nf
If <d and Nb <d, both the leading bit Pa and the trailing bit Pb are set to "0" so as to observe the run length restriction rule (d, k) (step 10).
2).

On the other hand, if the condition of step 101 is not satisfied, it is determined whether Nf <d (step 10).
3) If Nf <d, it is determined whether or not (Nf + Nm + Nb) is larger than the maximum value k of the run-length limit length (step 104). When determining Nm,
The determination is made on the assumption that Pa and Pb in Nm are both "0" (hereinafter the same). (Nf + Nm + Nb)> k
In order to comply with the run length restriction rule, one of the leading bit Pa and the trailing bit Pb is set to “1”.
From the condition that the sign is inverted on the rear side as much as possible, Pb
Is set to "1" (step 105). (Nf + Nm
+ Nb) is equal to or smaller than k, since the run-length restriction rule is followed, the first bit Pa and the last bit Pb
Are both set to "0" (step 106).

When it is determined in step 103 that Nf is not less than d, it is determined whether Nb <d (step 107). When Nb <d, (Nf + Nm + N
It is determined whether or not b) is larger than the maximum value k of the run-length limit length (step 108). If it is large, one of the leading bit Pa and the trailing bit Pb is set to "1" in order to comply with the run length restriction rule, but only N is equal to or greater than d, so only Pa is set to "1" (step 109). ).
When (Nf + Nm + Nb) is equal to or smaller than k, the run-length restriction rule is followed, so that both the leading bit Pa and the trailing bit Pb are set to “0” (step 11).
0).

When it is determined in step 107 that Nb is not smaller than d, "0" immediately before the margin bit is set.
And the number of the immediately following “0” are both d or more,
(Nf + Nm + Nb) is the maximum value k of the run length limit length
It is determined whether the value is larger than the threshold value (step 111). If the value is equal to or less than k, a DSV operation is performed before or after the margin bit is inserted (in the case of pre-reading).
C1 or C2 whose DSV (digital sum value) is reduced is selected (step 112). When C2 is selected, both the first bit Pa and the last bit Pb are set to "0" (step 113). When C1 is selected, Only Pb is set to "1" (step 114).

In the flowchart of FIG.
1 is a case where it is desired to invert the polarity after the margin bit by one inversion, and C2 is a case where the polarity is maintained without inversion or twice inversion.

If it is determined in step 111 that (Nf + Nm + Nb) is equal to or greater than k, the value exceeds the maximum value k of the run-length restriction rule, so that (Nf + Nm)> k and (Nm + Nb-1) ≦ k It is determined whether there is any data (step 115). If the condition is satisfied, the sum of the margin bit and the number of “0” immediately before the margin bit is larger than k.
V calculation is performed, and C1 or C2 whose DSV is reduced is selected based on the calculation result (step 11).
6), when C1 is selected, only the first bit Pa is set to "1" (step 117), and when C2 is selected, both Pa and Pb are set to "1" (step 118).

If the condition of step 115 is not satisfied, (Nf + Nm-1) ≦ k and (Nm + Nb)
It is determined whether or not> k (step 119). If the condition is satisfied, since the sum of the margin bit and the number of “0” immediately after the margin bit is larger than k, a DSV operation is performed, and based on the operation result, Then, C1 or C2 whose DSV becomes smaller is selected (step 120). When C1 is selected, only the last bit Pb is set to "1" (step 121). When C2 is selected, both Pa and Pb are set to "1". (Step 1
22). If the condition of step 119 is not satisfied, P
Both a and Pb are set to "1" (step 123).

The margin bit insertion block 182 shown in FIG.
The margin bits generated as described above correspond to the pre-pit positions in the information signal (recording data) before NRZI modulation input to the margin bit insertion block 182 as shown in FIG. After being inserted at the timing, it is converted into an NRZI signal by the NRZI converter 183,
The modulated signal is supplied to the power control circuit 19 and converted into a modulated signal based on the recording clock signal supplied from the recording clock signal generator 14 and output to the laser drive circuit 12 as a recording signal, as described above. Is done.

As a result, the relationship between the margin bits recorded in the groove portion on the optical disk and the pre-pits and wobbles recorded in advance in the land portion is as shown in FIG. In the figure, SY is synchronization information for one sync block period (the same as the one sync frame period), and is encoded and recorded in synchronization with the recording clock signal so that the leading pre-pit p1 is contained.

The pre-pits p2 and p3 correspond to other wobbles W adjacent to the record information following the above-mentioned synchronization information SY.
Of the pre-pits p2 and p3
, That is, in the adjacent groove part,
The margin bits m1 and m2 are recorded. This allows
Interference between the pre-pits p2 and p3 and the margin bits m1 and m2 can be reduced.

Even when margin bits are inserted into the recording information signal, if it is not desired to change the integer ratio relationship between the channel bit clock frequency of the information signal to be recorded on the conventional optical disc and the wobble frequency, a basic operation is required. The additional bits added to the recording information signal during one sync block period may be set to a multiple of the number of wobbles during one sync block period. For example, when the number of wobbles in one sync block period is 3, the number of additional bits may be a multiple of 3. FIG. 6 shows the relationship between prepits, wobbles and margin bits at this time. 5, the same parts as those of FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted.

Although the allocation of the additional bits to the margin bits is free, if all the additional bits are to be allocated to the margin bits, candidates for the length of the margin bits include 3T, 6T, 9T, and 12T. It is sufficient to select the most appropriate part while observing the state of interference (however, it must be selected within a range that satisfies the condition of FIG. 1). As a result, the frequency of the channel bit clock is always an integral multiple of the wobble frequency.

In FIGS. 5 and 6, a flat portion in the synchronization information SY is drawn so as to be synchronized with the pre-pits. However, it is needless to say that the synchronization information SY may be replaced with a margin bit without being synchronized.

Next, another embodiment of the main part of the present invention will be described. FIG. 7 shows an internal block diagram of an encoder for realizing another embodiment of the information recording method according to the present invention. 3, the same components as those of FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted. 7, the encoder 18 includes a code modulation block 184 and an NRZI converter 183.

In the present embodiment, the code modulation block 184
The feature is that it is provided. The code modulation block 184
The pre-pit position information detected in the recording clock signal generator 14 is supplied together with the recording clock signal. When code modulation is performed on the recording signal input from the CPU 16, the pre-pit position information will be described with reference to the flowchart of FIG. After an appropriate margin bit is generated by the above method, it is inserted at a timing corresponding to the pre-pit position based on the pre-pit position information.

In this embodiment, since the code modulation and the insertion of the margin bit are performed at the same time, the DSV control and the like can be shared.

Next, a method of reproducing a recording medium according to the present invention will be described. Although the hardware configuration of the playback device itself is the same as the conventional one, the algorithm of the playback method is slightly different from the conventional one. That is, in the optical disk of the above embodiment, as shown in FIG. 5 or FIG. 6, margin bits are inserted into the information signal (recording data) so that margin bits are recorded at positions adjacent to the prepits. Therefore, at the time of reproduction, based on the pre-pit detection signal obtained by detecting the pre-pit signal included in the reproduction signal, if the signal reproduced from the position of the groove portion corresponding to the pre-pit position is a margin bit By discriminating and ignoring the reproduction signal from this position and decoding the reproduction signal,
The original information signal is reproduced.

The present invention is not limited to the above embodiments. For example, the method of generating margin bits is as follows.
The method is not limited to the method of the flowchart of FIG. 4.
In some cases, DSV control is not required, in which case there is no corresponding branch in FIG. 4 and the degree of freedom in selection is increased. Further, the present invention can be applied to an optical disc in which an information signal is recorded on a land portion of the groove portion and the land portion. Further, the present invention is applicable not only to optical disks but also to other media as long as the relationship between the pre-pits and the recording signal is satisfied.

[0046]

As described above, according to the present invention,
Since the margin bits that do not affect the reading of the pre-pits are recorded and reproduced during the period including the position of the pre-pits, interference between the information signal and the pre-pit signal is reduced, and each piece of information is reproduced accurately. Can be.
At this time, the pattern of the margin bits is determined in consideration of the run-length constraint of the recording signal and the DSV, so that the DC component of the signal can be reduced and a recording / reproducing system advantageous for reproduction can be constructed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a positional relationship between a prepit and a recording signal according to an embodiment of an information signal recording method according to the present invention.

FIG. 2 is a block diagram of an example of an optical disk device to which the information signal recording method according to the present invention is applied.

FIG. 3 is an internal block diagram of an encoder that realizes an embodiment of an information recording method according to the present invention.

FIG. 4 is a flowchart illustrating an example of a method of generating margin bits generated by the encoder of FIG. 3 and inserted into a recording signal.

FIG. 5 is a diagram illustrating an example of a relationship between prepits, wobbles, and margin bits.

FIG. 6 is a diagram illustrating another example of the relationship between prepits, wobbles, and margin bits.

FIG. 7 is an internal block diagram of an encoder for realizing another embodiment of the information recording method according to the present invention.

[Explanation of symbols]

 Reference Signs List 11 optical head 14 clock signal generator 16 for recording 16 central processing unit (CPU) 18 encoder 19 power control circuit 181 code modulation block 182 margin bit insertion block 183 NRZI converter 184 code modulation block with margin bit insertion function

Continuation of the front page (72) Inventor Atsushi Hayami 3-12-12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 5D090 AA01 BB04 CC14 DD03 DD05 FF15 FF45 GG02 GG09 GG10 GG17 GG22 GG27

Claims (5)

[Claims] 1. A groove or a land is formed concentrically or spirally from the innermost circumference to the outermost circumference, and one or both sides of the groove or the land are continuously formed with wobbles. A land portion or a groove portion exists between adjacent groove portions or land portions, and the groove portion of the recording medium in which auxiliary information is recorded at predetermined intervals as pre-pits in the land portion or the groove portion in advance. Alternatively, in the information signal recording method for recording an information signal on a land portion, the margin is added to the information signal so that a margin bit of a predetermined bit pattern is recorded at a position adjacent to the prepit in the groove portion or the land portion. An information signal recording method characterized by recording by inserting bits. 2. The bit pattern according to claim 1, wherein the predetermined bit pattern of the margin bits corresponds to a run-length limit of the information signal and does not affect the reading of the pre-pits. Information signal recording method described. 3. A predetermined bit pattern of the margin bit is selected in consideration of a DSV of the information signal and a bit pattern which does not affect reading of the pre-pit is selected. Information signal recording method described. 4. A groove or land is formed concentrically or spirally from the innermost circumference to the outermost circumference, and one or both sides of the groove or land are formed with a continuous wobble. A land or a groove exists between adjacent grooves or lands, and auxiliary information is recorded in the land or the groove in advance as pre-pits at predetermined intervals. A recording medium on which an information signal is recorded, wherein a margin bit of a predetermined bit pattern is recorded at a position adjacent to the prepit in the groove portion or the land portion. 5. A groove or land is formed concentrically or spirally from the innermost circumference to the outermost circumference, and one or both sides of the groove or land are continuously formed with wobbles. A land or a groove exists between adjacent grooves or lands, and auxiliary information is recorded in the land or the groove in advance as pre-pits at predetermined intervals. An information signal reproducing method for reproducing the information signal from a recording medium in which the margin bit is inserted into the information signal so that a margin bit of a predetermined bit pattern is adjacent to the pre-pit in the recording medium. Based on the pre-pit signal obtained by detecting the pre-pit signal included in the reproduced signal from An information signal reproducing method comprising: determining a position of a margin bit; and ignoring a reproduction signal from the position of the margin bit, and reproducing the information signal.