JP3767344B2 - Information signal recording method, reproducing method, and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information signal recording method, a reproducing method, and a recording medium, and in particular, an information signal recording method for recording information signals at high density on a recording medium such as an optical disc, a reproducing method for reproducing recorded information signals on the recording medium, and an information signal. The present invention relates to a recorded recording medium.
[0002]
[Prior art]
Conventionally, pre-pit information is recorded in advance, and DVD-R (DVD-Recordable) and DVD-RW (DVD-Rewritable) are known as recording media on which information can be rewritten based on the prepit information. Hereinafter, the relationship between the pre-pits of the optical disc and the recording signal based on the DVD-RW standard will be described as an example.
[0003]
As described in Japanese Patent Laid-Open No. 10-293926, etc., the above-mentioned standard optical disc has, for example, a spiral groove portion or land portion, and one side or both sides of the groove portion continuously undulate. A land portion exists between groove portions adjacent to each other in the disk radial direction, and auxiliary information is recorded in advance as prepits in the land portion. For this optical disc, the information signal is recorded in the groove portion.
[0004]
Further, during recording of this optical disc, the reflected light obtained by irradiating the optical beam with the optical beam is received by a known two-divided photodetector, and the two received light signals obtained by the above-described pre-pit method by the known push-pull method. Auxiliary information is acquired by detecting the signal, and a wobble signal is extracted from the groove part to extract a recording clock signal synchronized with the rotation of the optical disk. Further, based on the differential signal obtained by the push-pull method, the optical beam spot is scanned on the groove portion to record the information signal.
[0005]
Here, the information signal to be recorded is recorded in sync frame units having a length of 1488 times the unit length T corresponding to the pit interval defined by the recording format. This sync frame is defined to include synchronization information Sync having a length of 14T from the beginning. On the other hand, the auxiliary information recorded by the pre-pit is within one sync frame of the recording signal recorded in the groove portion, at the land portion adjacent to the recording position of the synchronization information Sync, and at the apex of the wobble The pre-pit recording period is 2 sync frames.
[0006]
That is, the sync information Sync of the sync frame of the information signal to be recorded is encoded and recorded in synchronization with the recording clock signal so that the pre-pits are accommodated. In addition to the position adjacent to the above-mentioned synchronization information Sync, the prepit may exist at the apex of other wobbles adjacent to the recording information following the synchronization information Sync, and this is used for information such as a physical address. is doing.
[0007]
[Problems to be solved by the invention]
In the above conventional information signal recording method, when the interference between the prepit and the recording information signal is considered, the prepit Sync at the head of the prepit is centered in the flat sync information Sync recording period of 14T from the head of the sync frame of the recording signal. By synchronizing with each other, the mutual interference is reduced.
[0008]
However, other pre-pits directly interfere with random recording signals, causing pre-pits to fall in level and phase shift, increasing misclassification, and as a result, correct recording or playback cannot be performed. On the other hand, since noise is superimposed on the recording signal, the error rate is deteriorated. Since this tendency becomes more prominent as the recording density becomes higher, a method for reducing mutual interference has been desired.
[0009]
Further, at the time of recording, the large power output of the writing laser has a great influence on the detection of prepits, and there is a problem that correct recording cannot be performed.
[0010]
The present invention has been made in view of the above points, and an object thereof is to provide an information signal recording method, a reproducing method, and a recording medium that can reduce interference between a recording signal and a prepit.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has a groove portion or land portion formed concentrically or spirally, and one side or both sides of the groove portion or land portion are continuously formed with wobbles, There is a land portion or groove portion between adjacent groove portions or land portions, and in the land portion or groove portion, auxiliary information is recorded in advance as prepits at a predetermined interval in the groove portion or land portion of the recording medium. In an information signal recording method for recording an information signal, a margin bit is inserted into an information signal and recorded so that a margin bit of a predetermined bit pattern is recorded at a position adjacent to a pre-pit of a groove portion or a land portion. Features. According to the present invention, margin bits that do not affect the reading of the prepits can be recorded in the period including the position of the prepits.
[0012]
In order to achieve the above object, the recording medium of the present invention has a groove portion or land portion formed concentrically or spirally, and one side or both sides of the groove portion or land portion continuously have wobbles. In addition, a land portion or a groove portion exists between adjacent groove portions or land portions, and auxiliary information is recorded in advance as prepits in the land portions or groove portions at predetermined intervals. In the recording medium in which the information signal is recorded in the land portion, a margin bit of a predetermined bit pattern is recorded at a position adjacent to the prepits in the groove portion or the land portion. According to the present invention, it is possible to provide a recording medium on which margin bits that do not affect the reading of the prepits are recorded in a period including the position of the prepits.
[0013]
In order to achieve the above object, the information signal reproducing method of the present invention has a groove portion or land portion formed concentrically or spirally, and one side or both sides of the groove portion or land portion are continuously wobbled. In addition, land portions or groove portions exist between adjacent groove portions or land portions, and auxiliary information is recorded in advance as prepits at predetermined intervals in the land portions or groove portions. In an information signal reproduction method for reproducing an information signal from a recording medium in which a margin bit is inserted in an information signal so that a margin bit of a predetermined bit pattern is adjacent to a pre-pit in a portion or a land portion, Based on the prepit signal obtained by detecting the prepit signal included in the playback signal of Determine the position of Nbitto, ignoring the reproduced signal from the position of the margin bit, and performs the reproduction of the information signal.
[0014]
In the present invention, margin bits that do not affect the reading of the prepits are reproduced during the period including the position of the prepits, so that the original information signal can be reproduced by ignoring the margin bits.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a positional relationship among a reproduction pre-pit, a recording signal, and a write write pulse in the first embodiment of the information signal recording method according to the present invention. In this embodiment, a groove portion is formed concentrically or spirally, and one side or both sides of the groove portion are continuously formed with undulations (wobbles). There is a land portion in between, auxiliary information is recorded in advance as prepits in the land portion, and information signals are recorded in the groove portion. For example, the present invention is applied to an optical disc such as a rewritable DVD-R or DVD-RW. Is.
[0016]
In the present embodiment, in this optical disc, the recording is performed by inserting margin bits MB as shown in FIG. 1B in the recording information signal, and the insertion position of the margin bits MB in the information signal is further recorded. 1 so that the bit pattern of the margin bit MB becomes the erase period (erase period) TE of the write pulse for writing shown in FIG. 1 (D). The value is set to be a value as shown in (C) (in this case, “0”). FIG. 1A shows a reproduction pre-pit signal.
[0017]
FIG. 1C shows an example of a waveform of an information signal (recording data) before NRZI conversion. As described above, a margin bit MB is inserted in the erase period TE of the write pulse. Here, the erasing period of the write pulse shown in FIG. 1D is when the write pulse is at a level higher than the zero level by Pe, and the relationship between the write pulse and the recording data is known and will be described later.
[0018]
Here, the relationship between the prepits and the margin bits will be further explained. Inserted in the information signal as shown in FIG. 2B at the position of the groove adjacent to the prepit recording position shown in FIG. The margin bits MB recorded in this manner are bits having a total number of bits Nm, in which there are several consecutive “0” s between the first bit Pa and the last bit Pb before the NRZI conversion. Follow restriction rules (d, k). The run length restriction rule (d, k) is a rule in which “0” is a minimum of “d” and “k” is continuous between “1” and “1”.
[0019]
Further, as shown in FIG. 2B, immediately before the margin bit MB, the number of “0” s continues for Nf, and immediately after the margin bit MB, the number of “0” s continues for Nb. Further, as shown in FIG. 2A, the number of bits from the front edge of the prepit to the margin bit MB insertion position is Ns.
[0020]
As can be seen from FIGS. 2A and 2B, since the sign inversion is not performed in the central section of the margin bit MB adjacent to the prepit, the influence on the prepit of the recording signal is greatly reduced. The influence on the recording signal (information part) from the pre-pit naturally decreases because the distance is increased by the insertion of the margin bit MB. Note that the values of the leading bit Pa and the trailing bit Pb of the margin bit MB are appropriately determined by an encoder in the recording apparatus, as will be described later.
[0021]
FIG. 3 is a block diagram showing an example of an optical disc apparatus to which the information signal recording method according to the present invention is applied. In the figure, an optical head 11 has a light source, an optical system such as an objective lens, a photodetector, etc., and at the time of recording, a laser driving signal based on recording information data supplied from a laser driving circuit 12. Accordingly, the emission power of the light beam from the light source is changed and the information recording surface of the optical disk (not shown) is irradiated with the light beam to record the record information data. During reproduction, the optical disk is irradiated with a light beam with a constant emission power (reading power), and the reflected light is received by a photodetector in the optical head 11.
[0022]
Further, the optical head 11 receives reflected light from the information recording surface of the light beam irradiated on the information recording surface of the optical disc by a photodetector in the optical head 11 and converts it into an electrical signal, for example, a radial push By performing arithmetic processing based on the pull method, a detection signal carrying wobble signals of prepits and grooves and recorded information data is generated and output to the reproduction amplifier 13.
[0023]
The regenerative amplifier 13 amplifies the prepit signal from the land portion output from the optical head 11 and the detection signal carrying the wobble signal of the groove portion, and sends the information signal including the prepit signal and the wobble signal to the recording clock signal generator 14. At the same time as being supplied, an amplified signal corresponding to the recording information data is output to the decoder 15 during reproduction. The decoder 15 decodes and binarizes the input amplified signal, and then performs 8/16 demodulation and deinterleaving to decode the input amplified signal and generate a demodulated signal. Output to the device (CPU) 16.
[0024]
On the other hand, the recording clock signal generator 14 determines the maximum amplitude value of the wobble signal from the composite signal in which the prepit 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. A pre-pit signal is detected by comparing with a large level and supplied to the pre-pit decoder 17, and a wobble signal is extracted by binarizing the composite signal, and a recording clock signal that is phase-synchronized with this wobble signal Is generated and supplied to the encoder 18, and a rotation control signal is generated based on the difference signal between the recording clock signal and the reference clock signal, and is output to a motor drive system (not shown).
[0025]
The prepit decoder 17 decodes the auxiliary information from the supplied prepit detection signal and outputs it to the CPU 16. The CPU 16 performs an interface operation for capturing the recording information data transmitted from a host computer or the like (not shown) into the recording apparatus, and outputs the input recording information data to the encoder 18.
[0026]
The encoder 18 uses the recording clock signal supplied from the recording clock signal generator 14 as a timing signal, performs ECC processing, 8/16 modulation processing, and scramble processing, generates a modulation signal, and outputs it to the power control circuit 19. To do. Further, the encoder 18 performs a process of inserting margin bits generated as described later into the recording information data based on the pre-pit position information supplied from the recording clock signal generator 14.
[0027]
The power control circuit 19 converts the waveform of the modulation signal (so-called write 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. (Strategy processing) and output to the laser drive circuit 12 as a recording signal. The laser drive circuit 12 drives a light source in the optical head 11 and outputs a laser drive signal for emitting a light beam with an emission power corresponding to the supplied recording signal. At the time of 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 disc corresponding to the address information. .
[0028]
Here, the write strategy process uses a plurality of laser pulses having three power levels. The three power levels are, in order from the highest, peak power (write power), medium power (erase power), and bias power (read power). The peak power level is indicated by Po in FIGS. 1 (D) and 4 (B). When the optical disk is irradiated with the laser light of this peak power, the recording film of the optical disk is melted and then rapidly cooled, It becomes an amorphous state where the reflectance of light is low. This is used as a recording mark.
[0029]
The level of the medium power is indicated by Pe in FIGS. 1D and 4B, and when the optical disk is irradiated with the laser light having the medium power, the recording film is brought into a crystalline state. Therefore, if the above-mentioned medium power laser light is irradiated onto the portion of the optical disk that was in an amorphous state before the laser light irradiation, it changes to a crystalline state, and the original crystalline state is maintained as it is. Is done. Therefore, the recording mark can be erased by the above medium power laser beam. Further, the level of the bias power is indicated by Pb in FIGS. 1D and 4B, and the recorded information can be read by irradiating the optical disk with the laser light of this bias power. This is because there is no change in the state of the optical disk.
[0030]
Here, the recording data (information signal) before NRZI conversion shown in FIGS. 1C and 4A is 8 / 16-modulated encoded data, and the write pulse is “1” when recording. As shown in FIGS. 1D and 4B, a peak power pulse having a width of about 0.5 Tw, which is about ½ times the length Tw of 1-bit width of recording data, The pulse of bias power having a width of 0.5 Tw is alternately repeated to suppress heat accumulation during recording. The relationship between FIGS. 4A and 4B is well known.
[0031]
In the present embodiment, margin bits are set by the encoder 18 so that margin bits are inserted into the information signal (recording data) and the margin bit recording period is the write pulse erasing (erasing) period. Is done. FIG. 5 shows an internal block diagram of an encoder for realizing each embodiment of the information recording method according to the present invention. In the figure, the same components as those in FIG. In FIG. 5, the encoder 18 includes a code modulation block 181, a margin bit insertion block 182, and an NRZI converter 183.
[0032]
Among these, the code modulation block 181 and the NRZI converter 183 are configured in a conventional encoder, and this embodiment is characterized in that a margin bit insertion block 182 is provided between them. . The margin bit insertion block 182 is supplied with pre-pit position information detected in the recording clock signal generator 14, and the recording signal input from the code modulation block 181 based on this pre-pit position information is added to FIG. The Pa and Pb are determined according to the flowchart shown in FIG.
[0033]
Next, a margin bit generation method according to the first embodiment of the recording method of the present invention will be described with reference to the flowchart of FIG. In determining the first bit Pa and the last bit Pb of the margin bits, (1) observe the run length restriction rule (d, k), (2) use DSV control that appropriately controls the DC level, and (3) In order not to affect the land pre-pit (LPP), the inversion is as small as possible, and (4) in the case of inversion, the inversion is as far back as possible.
[0034]
That is, the margin bit insertion block 182 in the encoder 18 first has the number of consecutive “0” s Nf immediately before the margin bit of the information signal smaller than d and the number of consecutive “0” s Nb immediately after the margin bit. Is smaller than d (step 101). When Nf <d and Nb <d, the leading bit Pa and the trailing bit are observed so as to observe the run length restriction rule (d, k). Both Pb are set to “0” (step 102).
[0035]
On the other hand, if the condition of step 101 is not satisfied, it is determined whether Nf <d (step 103). If Nf <d, whether (Nf + Nm + Nb) is greater than the maximum run length limit length k. Determination is made (step 104). When determining Nm, it is assumed that both Pa and Pb in Nm are “0” (the same applies hereinafter). When (Nf + Nm + Nb)> k, one of the first bit Pa and the last bit Pb is set to “1” in order to comply with the run length restriction rule, but only Pb is set to “1” from the condition that the sign is inverted as much as possible. "(Step 105). When (Nf + Nm + Nb) is less than or equal to k, the run length restriction rule is observed, so both the leading bit Pa and the trailing bit Pb are set to “0” (step 106).
[0036]
If it is determined in step 103 that Nf is greater than or equal to d, it is determined whether Nb <d (step 107). When Nb <d, it is determined whether (Nf + Nm + Nb) is larger than the maximum value k of the run length limit length (step 108). If it is large, one of the first bit Pa and the last bit Pb is set to “1” in order to comply with the run length restriction rule, but since Nf is equal to or greater than d, only Pa is set to “1” (step 109). ). When (Nf + Nm + Nb) is less than or equal to k, the run length restriction rule is observed, so both the leading bit Pa and the trailing bit Pb are set to “0” (step 110).
[0037]
If it is determined in step 107 that Nb is greater than or equal to d, the number of “0” immediately before the margin bit and the number of “0” immediately after the margin bit are both greater than or equal to d, so (Nf + Nm + Nb) is run. It is determined whether the length limit length is greater than the maximum value k (step 111). If the length limit length is not greater than k, polarity control is performed (step 112). This polarity control is performed so that the polarity of the flat portion of the number of bits Nm−2 following the margin bit Pa before the NRZI conversion becomes the polarity corresponding to the erasing period (in the example of FIG. 1, as shown in FIG. 1C). Pa is set to “1” or “0”.
[0038]
When Pa is set to “1” (PA1), the process proceeds to step 113 and DSV control is performed. When Pa is set to “0” (PA2), the process proceeds to step 114 and DSV control is performed. In the DSV control, DSV calculation is performed before or after margin bit insertion (in the case of prefetching), and C1 or C2 is selected based on the calculation result so that the DSV (digital sum value) becomes small. In the DSV control at step 113, Pa is “1”, Pb is set to “1” when C2 is selected (step 115), and Pb is set to “0” when C1 is selected (step 116). In the DSV control in step 114, Pa is “0”, Pb is set to “0” when C2 is selected (step 117), and Pb is set to “1” when C1 is selected (step 118).
[0039]
In the flowchart of FIG. 6 and FIG. 11 to be described later, the above C1 is a case where the polarity after the margin bit is to be inverted by one inversion, and the above C2 is not inverted or the polarity is maintained by inversion twice. This is the case.
[0040]
When it is determined in step 111 that (Nf + Nm + Nb) is greater than or equal to k, the maximum value k of the run length restriction rule is exceeded, so whether (Nf + Nm)> k and (Nm + Nb−1) ≦ k. When the determination is made (step 119) and the condition is satisfied, the sum of the number of margin bits and the immediately preceding “0” is greater than k, so DSV calculation is performed, and the DSV is reduced based on the calculation result. C1 or C2 is selected (step 120). When C1 is selected, only the first bit Pa is set to "1" (step 121), and when C2 is selected, both Pa and Pb are set to "1" (step 122). .
[0041]
If the condition of step 119 is not satisfied, it is determined whether (Nf + Nm−1) ≦ k and (Nm + Nb)> k (step 123). If the condition is satisfied, the margin bit and the immediately following bit are determined. Since the sum of the numbers of “0” is greater than k, polarity control is performed (step 124). As described above, this polarity control is performed so that the polarity of the flat portion of the number of bits Nm−2 following the margin bit Pa before the NRZI conversion becomes the polarity corresponding to the erasing period (in the example of FIG. As shown in (C), Pa is set to “1” or “0”.
[0042]
When Pa is set to “1” (PA1), the process proceeds to step 126 and Pb is set to “1”, and when Pa is set to “0” (PA2), the process proceeds to step 125 and Pb is set to “1”. When the condition of step 123 is satisfied, there is no room for DSV control, so only polarity control is performed as described above. If the condition of step 123 is not satisfied, both Pa and Pb are set to “1” (step 127).
[0043]
The margin bits generated as described above in the margin bit insertion block 182 of FIG. 5 are shown in FIG. 2B in the information signal (recording data) before NRZI modulation input to the margin bit insertion block 182. As shown, after being inserted at a timing corresponding to the pre-pit position, it is converted into an NRZI signal by the NRZI converter 183 and supplied to the power control circuit 19, and as described above, supplied from the recording clock signal generator 14 here. Based on the recorded recording clock signal, the waveform of the modulation signal is converted and output to the laser driving circuit 12 as a writing write pulse corresponding to the recording information.
[0044]
As a result, the relationship between the margin bits recorded in the groove portion on the optical disc and the prepits and wobbles recorded in advance in the land portion is as shown in FIG. In the drawing, SY is synchronization information of one sync block period (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 accommodated.
[0045]
Further, the prepits p2 and p3 are present at the vertices of other wobbles W adjacent to the recording information following the synchronization information SY, and are located at positions corresponding to the prepits p2 and p3, that is, in the adjacent groove portions. , Margin bits m1 and m2 are recorded. Thereby, interference between the prepits p2 and p3 and the recording information can be reduced.
[0046]
Further, as shown in FIG. 1D, the write pulse for writing in the margin bit period is erased using medium power instead of the conventional recording period using peak power by setting the bit pattern of the margin bit. Since the period is set, it is possible to reduce the influence of the write pulse on the reading of the prepit information during recording.
[0047]
Even when a margin bit is inserted in 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, basically one sync. The additional bits added to the recording information signal during the block period may be 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. 8 shows the relationship between prepits, wobbles, and margin bits at this time. In the figure, the same parts as those in FIG.
[0048]
Although the allocation of the additional bits to the margin bits is free, when all the additional bits are allocated to the margin bits, the margin bit length candidates include 3T, 6T, 9T, and 12T. You can select the most appropriate place while looking at the status. Thereby, the frequency of the channel bit clock is always an integer multiple of the wobble frequency.
[0049]
In FIGS. 7 and 8, the flat portion in the synchronization information SY is drawn so as to be synchronized with the pre-pits, but it goes without saying that it may be replaced with a margin bit without being synchronized.
[0050]
Next, a second embodiment of the information recording method according to the present invention will be described. FIG. 9 shows the positional relationship among the reproduction pre-pit, the recording signal, and the write write pulse in the second embodiment of the information signal recording method according to the present invention. In the present embodiment, recording is performed by inserting a margin bit MB into a recording information signal as shown in FIG. 2B on an optical disc, and the insertion position of the margin bit MB in the information signal is further recorded. Is placed at the pre-bit position of the adjacent groove portion, and the write pulse for writing at the position where the flat portion II in the synchronization information SY in the recording signal after NRZI conversion shown in FIG. A bit pattern of past margin bits is set so that an erasing period as indicated by III in FIG. FIG. 9A shows a reproduction pre-pit signal.
[0051]
For example, as shown in FIG. 7, the synchronization information SY is encoded and recorded in synchronization with the recording clock signal so that the leading pre-pit p1 is accommodated. The prepits p2 and p3 are present at the apexes of other wobbles W adjacent to the recording information following the synchronization information SY, and margin bits m1 and m2 are recorded at positions corresponding to the prepits p2 and p3. Is done.
[0052]
Next, a margin bit generation method according to the second embodiment of the recording method of the present invention will be described with reference to the flowcharts of FIGS. 10 and 11, the same processing steps as those in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted. In the second embodiment, when it is determined in step 111 that (Nf + Nm + Nb) is equal to or less than the maximum value k of the run length limit length, the synchronization signal SYNC (synchronization information SY) is generated until the next margin bit is inserted. It is determined whether or not it exists (step 131 in FIG. 11). If it does not exist, DSV control is performed in the same manner as in the first embodiment (step 114 in FIG. 11). Perform (step 132 in FIG. 11).
[0053]
In the SYNC polarity control, the polarity of the flat portion in the synchronization information SY that appears next in the recording data after NRZI conversion corresponds to the polarity corresponding to the erase period III of the write pulse shown in FIG. In the example of B), a process of selecting the first bit Pa and the last bit Pb of the past margin bits of the synchronization information SY is performed so as to be “0”). When the polarity after the margin bit is inverted by one inversion by the SYNC polarity control in step 132 (C1), Pa = 0 and Pb = 1 (step 134 in FIG. 11), no inversion, or inversion twice When the polarity is maintained by (C2), Pa = 1 and Pb = 1 are set (step 133 in FIG. 11).
[0054]
If it is determined in step 119 that (Nf + Nm)> k and (Nm + Nb−1) ≦ k, the sum of the number of margin bits and the immediately preceding “0” is greater than k. Also in this case, it is determined whether or not the synchronization signal SYNC (synchronization information SYNC) exists until the next margin bit insertion (step 135 in FIG. 11). If not, the DSV is the same as in the first embodiment. Control is performed (step 120 in FIG. 11), but if present, SYNC polarity control is performed (step 136 in FIG. 11).
[0055]
When the polarity after the margin bit is inverted by one inversion by the SYNC polarity control in step 136 (C1), Pa = 1 and Pb = 0 (step 137 in FIG. 11), no inversion or inversion twice When the polarity is maintained by (C2), Pa = 1 and Pb = 1 are set (step 137 in FIG. 11).
[0056]
Further, when it is determined in step 123 that (Nf + Nm−1) ≦ k and (Nm + Nb)> k, the sum of the margin bit and the number of “0” immediately after it is greater than k. Also in this case, it is determined whether or not the synchronization signal SYNC (synchronization information SYNC) is present until the next margin bit is inserted (step 139 in FIG. 11). If there is, the SYNC polarity control is performed (step in FIG. 11). 140).
[0057]
When the polarity after the margin bit is inverted by one inversion by the SYNC polarity control in step 140 (C1), Pa = 0 and Pb = 1 (step 141 in FIG. 11), no inversion or inversion twice When the polarity is maintained by (C2), Pa = 1 and Pb = 1 are set (step 142 in FIG. 11). If it is determined in step 139 that the synchronization signal SYNC (synchronization information SYNC) does not exist before the next margin bit is inserted, DSV control is performed (step 143 in FIG. 11). When the subsequent polarity is reversed (C1), Pa = 0 and Pb = 1 are set (step 144 in FIG. 11), and when the polarity is maintained by no reversal or twice reversed (C2), Pa = 1, Pb = 1 is set (step 145 in FIG. 11).
[0058]
As described above, according to the present embodiment, the insertion position of the margin bit MB in the information signal is set to the pre-bit position of the adjacent groove portion, and the recording after the NRZI conversion shown in FIG. 9B is performed. The bit pattern of the past margin bits is set so that the write pulse for writing at the position where the flat portion II exists in the synchronization information SY in the signal has an erasing period as indicated by III in FIG. 9C. As a result, the influence of the write pulse on the reading of the prepit information during recording can be reduced.
[0059]
Next, another embodiment of the main part of the present invention will be described. FIG. 12 shows an internal block diagram of an encoder that realizes another embodiment of the information recording method according to the present invention. In the figure, the same components as those in FIG. In FIG. 12, the encoder 18 includes a code modulation block 184 and an NRZI converter 183.
[0060]
The present embodiment is characterized in that a code modulation block 184 is provided. The code modulation block 184 is supplied with the prepit position information detected in the recording clock signal generator 14 together with the recording clock signal, and performs code modulation on the recording signal input from the CPU 16. An appropriate margin bit is generated by the method described with reference to the flowcharts of FIGS. 6 or 10 and FIG. 11, and then inserted at a timing corresponding to the prepit position based on the prepit position information. In this embodiment, since code modulation and margin bit insertion are performed simultaneously, DSV control and the like can be shared.
[0061]
Next, the reproducing method of the recording medium of the present invention will be described. The hardware configuration of the playback apparatus itself is the same as the conventional one, but the algorithm of the playback method is slightly different from the conventional one. That is, in the optical disc of the above embodiment, as shown in FIG. 7 or FIG. 8, the margin bit is inserted into the information signal (recording data) so that the margin bit is recorded at a position adjacent to the prepit. Therefore, at the time of reproduction, based on the prepit detection signal obtained by detecting the prepit signal included in the reproduction signal, the signal reproduced from the groove portion position corresponding to the prepit 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.
[0062]
Further, the present invention is not limited to the above-described embodiment. For example, the margin bit generation method is not limited to the method of the flowchart of FIG. 6 or FIG. 10 and FIG. There is a case where there is no length restriction, or there is a case where DSV control is not necessary. In this case, the corresponding branch in FIG. 6, FIG. 10 and FIG.
[0063]
The present invention can also be applied to an optical disc in which an information signal is recorded in a land portion of a groove portion and a land portion. Furthermore, the present invention can be applied not only to optical discs but also to other media as long as the relationship between prepits and recording signals is established.
[0064]
【The invention's effect】
As described above, according to the present invention, the bit pattern of the margin bit is set so that the write pulse of the margin bit period becomes the erasure period, or the write pulse of the flat part in the synchronization information is the erasure period. Thus, since the past margin bit pattern is set, it is possible to reduce the influence of the write pulse on the reading of the prepit information during recording.
[0065]
In addition, according to the present invention, margin bits that do not affect the reading of the prepits are recorded and reproduced during a period including the position of the prepits, thereby reducing interference between the information signal and the prepit signal, Can be reproduced accurately. At this time, the margin bit pattern is determined in consideration of the run length constraint of the recording signal and the DSV, thereby reducing the DC component of the signal and constructing a recording / reproducing system advantageous for reproduction.
[Brief description of the drawings]
FIG. 1 is a diagram showing a positional relationship among a reproduction pre-pit, a recording signal, and a write write pulse according to a first embodiment of the information signal recording method of the present invention.
FIG. 2 is a diagram showing the relationship between pre-pits and margin bits in each embodiment of the information signal recording method according to the present invention.
FIG. 3 is a block diagram of an example of an optical disc apparatus to which an information signal recording method according to the present invention is applied.
FIG. 4 is a diagram showing an example of a general relationship between recording data and a write pulse in a rewritable optical disc.
FIG. 5 is an internal block diagram of an encoder that realizes an embodiment of an information recording method according to the present invention.
FIG. 6 is a flowchart showing a method for generating margin bits generated according to the first embodiment of the recording method of the present invention and inserted into a recording signal.
FIG. 7 is a diagram illustrating an example of a relationship between pre-pits, wobbles, and margin bits.
FIG. 8 is a diagram illustrating another example of the relationship between pre-pits, wobbles, and margin bits.
FIG. 9 is a diagram showing a positional relationship among a reproduction pre-pit, a recording signal, and a write write pulse in the second embodiment of the information signal recording method according to the present invention.
FIG. 10 is a flowchart (No. 1) showing a method of generating margin bits generated by the second embodiment of the recording method of the present invention and inserted into a recording signal.
FIG. 11 is a flowchart (part 2) illustrating a method of generating margin bits generated according to the second embodiment of the recording method of the present invention and inserted into a recording signal.
FIG. 12 is an internal block diagram of an encoder that realizes another embodiment of the information recording method according to the present invention.
[Explanation of symbols]
11 Optical head
14 Clock signal generator 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
SY synchronization information
MB Margin bit
Pa First bit of margin bit
Pb Margin bit tail bit
Po Peak power (light power) level
Pe Medium Power (Erase Power) Level
Pb Bias power (read power) level

Claims (6)

A groove portion or land portion is formed concentrically or spirally, and one side or both sides of the groove portion or land portion are continuously formed with wobbles, and a land between adjacent groove portions or land portions is formed. In an information signal recording method for recording an information signal in the groove portion or land portion of a recording medium in which auxiliary information is previously recorded as prepits in the land portion or groove portion at a predetermined interval. ,
The margin bit is inserted into the information signal so that a margin bit is recorded at a position adjacent to the pre-pit in the groove portion or the land portion, and the write pulse for writing in the margin bit period becomes an erasing period. In addition, a bit pattern of the margin bits is set. A groove portion or land portion is formed concentrically or spirally, and one side or both sides of the groove portion or land portion are continuously formed with wobbles, and a land between adjacent groove portions or land portions is formed. In an information signal recording method for recording an information signal in the groove portion or land portion of a recording medium in which auxiliary information is previously recorded as prepits in the land portion or groove portion at a predetermined interval. ,
The margin bit is inserted into the information signal so that a margin bit is recorded at a position adjacent to the prepit in the groove portion or the land portion, and a write write at a position where the prepit exists during the synchronization signal period An information signal recording method, wherein a bit pattern of the margin bits is set so that a pulse is in an erasing period. 3. The information signal according to claim 1, wherein the bit pattern of the margin bit corresponds to a run-length limit of the information signal, and a bit pattern that does not affect reading of the prepit is selected. Recording method. 3. The information signal recording according to claim 1, wherein the predetermined bit pattern of the margin bits is selected in consideration of DSV of the information signal and not affecting the reading of the prepit. Method. A groove portion or land portion is formed concentrically or spirally, and one side or both sides of the groove portion or land portion are continuously formed with wobbles, and a land between adjacent groove portions or land portions is formed. In a recording medium in which auxiliary information is recorded as prepits at a predetermined interval in advance in the land portion or groove portion, and information signals are recorded in the groove portion or land portion.
A margin bit is inserted into the information signal so that the margin bit is recorded at a position adjacent to the pre-pit in the groove portion or land portion, and the write pulse for writing in the margin bit period becomes an erasing period. Or a recording medium in which the bit pattern of the margin bit is set and recorded such that a write pulse for writing at a position where the pre-pit exists in the synchronization signal period is an erasure period. A groove portion or land portion is formed concentrically or spirally, and one side or both sides of the groove portion or land portion are continuously formed with wobbles, and a land between adjacent groove portions or land portions is formed. Information such that a margin bit is adjacent to the pre-pit, and auxiliary information is recorded in advance as pre-pits in the land portion or groove portion as pre-pits. The margin bit is inserted and recorded in the signal, and the write write pulse in the margin bit period becomes the erase period, or the write write pulse in the position where the pre-pit exists in the synchronization signal period is erased The bit pattern of the margin bit is set so that it becomes a period An information signal reproducing method for reproducing the information signal from the recording medium being recorded,
Based on the prepit signal obtained by detecting the prepit signal included in the reproduction signal from the recording medium, the position of the margin bit is determined, the reproduction signal from the margin bit position is ignored, and the An information signal reproduction method comprising reproducing an information signal.

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