JP3381837B2 - Information recording medium - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a recording mark on a recording medium having different physical properties from other parts, and corresponding information to both ends of the mark. It relates to so-called mark edge recording in which recording is performed. The present invention is particularly suitable for a rewritable high-density information recording method for repeatedly rewriting and recording information,
It is also suitable for a so-called phase change type information recording method in which the physical property of the information recording section is changed by changing the temperature or the like of the information recording medium to cause a phase change of the recording material, thereby changing the physical properties of the information recording section. 2. Description of the Related Art A conventional rewritable information recording and recording method is disclosed, for example, in Japanese Patent Publication No. Hei.
No. 29625). This example shows a recording method of an optical disk for recording information by modulating the intensity of light. [0003] As shown in FIG. 6, information is divided into a plurality of sectors 21 and recorded. Identification information 2 indicating the physical position of the information is provided at the head of each sector.
4 are arranged. Based on this identification information 24,
The recording unit including the synchronization signal section 22 and the information recording section 23 is recorded on the medium. At this time, the recording start position of the recording unit is changed randomly at every rewriting, and recording is performed, thereby improving the number of repetitions of rewriting. That is, deterioration of the disk material due to repeated use of the same location in the sector is reduced, and the number of times of rewriting is improved. FIG. 7 shows the relationship between the number of rewrites and jitter when the same recording information is repeatedly recorded.
Here, the jitter is obtained by normalizing the standard deviation of the time lag between the reproduction clock and the reproduction data in the case where the same random data is repeatedly recorded by EFM modulation and then reproduced, and is standardized by the reproduction detection window width. Reference numeral 701 denotes a case where the shift amount of the recording start position is 2 bytes in mark edge recording, 702 denotes a case where the shift amount of the recording start position is 30 bytes in mark edge recording, and 703 denotes a recording start position in the mark position recording. If the shift amount is 2 bytes, 70
Reference numeral 4 denotes a case where the shift amount of the recording start position is 100 bytes in the mark edge recording, and reference numeral 705 denotes a case where the shift amount of the recording start position is 30 bytes in the mark position recording. Here, mark position recording is a method of recording information in correspondence with the position of a mark. It can be seen that as the amount of shift of the recording start position is increased, the increase in jitter after rewriting is suppressed and the number of rewritable times is improved. Here, in mark position recording in which data corresponds to the center position of a mark, the shortest mark interval was 0.9 μm, and in mark edge recording in which data corresponded to both ends of the mark, the shortest mark length was 0.6 μm. The recording / reproducing spot diameter was 0.9 μm, and a GeSbTe phase change recording medium was used as a recording medium. However, in the method of shifting the recording start position, as can be understood from the study in FIG.
In particular, in the case of mark edge recording, when the same recording information is repeatedly rewritten, it is necessary to increase the random recording start position change to about 100 bytes in order to obtain a practical number of rewritable times. For this reason, there is a problem that the use efficiency of the sector is significantly reduced.
Further, when such a large positional movement is performed, the start end and the end of the recording information overlap the recording information portion.
At the beginning and end of the recorded information, dissolution of the recording film,
Since the recording characteristics are likely to be degraded due to the flow and the like, there is a problem that the range of the influence of the change in the recording and reproducing characteristics due to repeated rewriting of these portions is expanded. A first object of the present invention is to provide a rewritable high-density information recording method for repeatedly rewriting and recording information by associating information with both ends of a mark. It is an object of the present invention to provide an information recording method for dramatically improving the information recording method. A second object of the present invention is to provide a rewritable high-density information recording method in which information is repeatedly rewritten and recorded by associating information with both ends of a mark. An object of the present invention is to provide an information recording / recording device for improving. In the present invention, the following means are used in order to achieve the first object. (1) In an information recording method in which a recording mark having a physical property different from that of another part on a recording medium and information is made to correspond to both ends of the mark and information is repeatedly rewritten and recorded, information is rewritten In addition, the mark portion and the space portion between the marks are almost randomly reversed and recorded. [0010] Thus, when the rewriting is repeatedly performed, the integrated recording times of the mark portion and the space portion on the medium become uniform regardless of the position of the medium, so that the change of the recording medium due to the repetitive recording becomes uniform. As a result, the number of rewrites that can be repeated is dramatically improved. This does not reduce the information recording efficiency at all. (2) A substantially random reversal is performed for each information recording unit. Here, the recording unit refers to a unit such as a sector that is actually recorded on a recording medium. That is, the information on the medium is not rewritten in a unit smaller than the recording unit. Of course, after reproducing the recording unit, only a part of the reproduction information is corrected and re-recorded, and a read-modify-write process is performed, so that the minimum unit of recording can be apparently reduced.
Even in this case, the unit in which recording and reproduction are actually performed on the medium is the above-described recording unit. If the reversal occurs in the middle of a recording unit, it is disadvantageous because complicated processing is required at the time of signal reproduction. As a result, the total number of times of recording becomes uniform irrespective of the position of the medium for each information recording unit. Since the reproduction process is generally performed for each information recording unit, the change of the recording medium due to the repetitive recording in the information recording unit is uniformed, and the number of times of rewriting can be remarkably improved. (3) An information recording method in which a recording mark having a physical property different from that of other parts on a recording medium and information is repeatedly rewritten and recorded by associating information with both ends of the mark. A synchronizing signal composed of a plurality of marks is arranged at the head of the recording unit, and each time information is rewritten, the number of marks of the synchronizing signal is changed so that the length of the synchronizing signal is changed almost at random. As described above, since the area where the synchronization signal is recorded is used as the adjustment area, the position of the information recording section changes substantially at random. Therefore, when rewriting is repeatedly performed, the mark section and the space on the medium are not changed. Since the total number of times of recording of a set becomes uniform irrespective of the position of the medium, the change of the recording medium due to repetitive recording is made uniform, and the number of rewrites that can be repeated is drastically improved. (4) An information recording method in which a recording mark having a physical property different from that of other parts on a recording medium, information is made to correspond to both ends of the mark, and the information is repeatedly rewritten and recorded, A synchronization signal consisting of a plurality of marks and spaces is arranged at the head of the information recording unit, and every time the information is rewritten, the length of the synchronization signal is changed almost randomly by changing the number of marks or spaces of the synchronization signal. At the same time, the mark part and the space part between the marks are reversed almost at random and recorded. As a result, when the rewriting is repeatedly performed, the uniformity of the integrated recording number of the mark portion and the space portion on the medium is further improved, so that the number of times of rewriting can be further improved. (5) A pseudo data section is provided at the rear end of the information recording section, and the length of the pseudo data section is changed in accordance with the length of the synchronization signal section so that the data can be transmitted from the synchronization section. The length of the entire recording unit from the head to the rear end of the pseudo data part is made substantially the same. This allows
Since the length of the entire recording unit is substantially the same, the influence of the change of the start and end of the information does not reach the information recording section, which is the central part of the information. , The decrease in the number of rewrites due to the influence of the change is suppressed. (6) Each time the information is rewritten, the recording start position of the information is changed almost randomly and recorded. As a result, when the rewriting is repeatedly performed, the uniformity of the integrated recording number of the mark portion and the space portion on the medium is further improved, so that the number of times of rewriting can be further improved. (7) Further, the change in the position is smaller than the change in the length of the synchronization signal. Thereby, despite the change in the information recording start position, the influence of the change of the start and end of the information is the central part of the information.
Since the information does not reach the information recording section, the number of rewrites due to the influence of changes in the start and end of the information is suppressed from being reduced, and the number of rewrites is greatly improved. In order to achieve the second object of the present invention, the following means are used. (8) In an information recording apparatus having at least a recording / reproducing head and a recording pulse generating circuit and recording information on a recording medium, at least a random signal generating circuit and a timing generating circuit are provided. At least one of a polarity inversion circuit for inverting the recording pulse polarity by a random signal generated by the generation circuit and a synchronization signal generation circuit having a function of changing the length of the synchronization signal is provided. [0020] This makes it possible to perform recording by changing at least one of the polarity and timing of the recording pulse. Therefore, when rewriting is repeatedly performed, the cumulative number of recordings of the mark portion and the space portion on the medium is repeated. And the number of times the recording medium can be repeatedly rewritten is improved.
Here, the recording pulse is not the pulse itself such as heat, light, and magnetic field applied to the medium during recording on the medium. The pulse actually applied to the medium is recorded after being converted into a divided pulse train or the like using a recording pulse shaping circuit or the like in accordance with the characteristics of the medium. (9) Further, the polarity of the recording pulse is inverted.
After the generation of the synchronization signal, the encoded data, and the pseudo data, the processing is performed after passing through the synthesizing circuit. As a result, the reversal of the polarity can be reliably realized without depending on the recording encoding circuit and method. (10) The configuration is such that the polarity of the synchronization signal generated by the synchronization signal generation circuit changes at least by the random signal. As a result, the recording pulse polarity can be automatically inverted without newly providing a polarity inversion circuit, which is useful for reducing the cost of the apparatus. As described above, according to the present invention, the binary information "0" or "1" is made to correspond to both ends of the recording mark,
A method of recording information on a recording medium in the form of a recording mark array.For example, when the same information is recorded a plurality of times, a plurality of recording mark arrays recorded on the recording medium corresponding to this information are included. The arrangement is characterized in that the arrangement of the space portions between the recording marks is reversed. As a result, even if the same information is repeatedly recorded, the position where the mark is formed by the irradiation of the energy beam is not shifted to a specific place of the medium and is evenly distributed over the entire surface, so that the life of the recording medium is extended. In the recording medium of the present invention, a plurality of sectors are arranged along a track, and each sector is arranged in a data area where recording data is recorded and in front of the data area. It has a sync signal area and a pseudo data area arranged at the rear of the data area. The length of the sync signal area in each sector is not constant, and the pseudo data area is located from the beginning of the sync signal area. Is characterized in that the length up to the end is constant. In a preferred embodiment, a plurality of sectors are arranged along the track, and each sector is a data area where recorded data is recorded, and first and second sectors arranged before and after the data area. 2 has an identification information section disposed before the first area, and the length of the first area in each sector is not constant, and the length of the second area from the beginning of the first area is The length to the end is constant, and the interval from the beginning of the first area to the end of the identification information section is not constant. In such a medium, it is possible to prevent the deterioration of the recording medium due to the irradiation of the energy beam from being shifted over the entire surface of the medium without largely moving the recording start position and the end position. Since the deterioration of the signal at the time of performing the recording can be reduced and the influence of the deterioration near the recording start position and the end position can be limited to the first and second adjustment areas, the reliability is high. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below using embodiments. << Embodiment 1 >> FIG. 5 shows an information recording apparatus according to an embodiment of the present invention. This apparatus has a recording / reproducing head that forms a recording mark by irradiating an energy beam to a recording medium based on a recording pulse corresponding to encoded recording data composed of binarized information. This is an information recording apparatus for recording information "1" or "0" in correspondence with the edge of the recording mark, and has a pulse conversion circuit for inverting the polarity of a recording pulse. The recording pulse whose polarity is inverted may be a pulse in which one of the binary information “1” and “0” corresponds to the rising and falling of the pulse. In this embodiment, a phase-change optical recording medium (recording film: GeSbTe system) is used as a recording medium. Therefore, the recording is performed by modulating the intensity of the laser beam and irradiating the recording medium with the laser beam, and the recording mark is formed in the form of an amorphous region in the crystalline region. In FIG. 5, a recording / reproducing head 32 for recording / reproducing on / from the recording medium 8 is provided. A reproducing signal from the recording / reproducing head 32 is detected by a detecting circuit 33, and the detected signal is reproduced by a reproducing circuit 41. Reproduction circuit 41
Has at least an identification information detection circuit 42 for detecting identification information on a medium. The timing generation circuit 40 controls various timings related to the recording operation according to the identification information signal from the identification information detection circuit 42. The apparatus according to the present embodiment has at least a random signal generating circuit 36. As a method of generating a random signal by the random signal generation circuit 36, for example, a pseudo random sequence generator may be provided inside the random signal generation circuit 36, or a random signal may be generated from a signal asynchronous with the recording / reproduction operation such as time. May be generated.
The apparatus according to the present embodiment further includes recording information (recording data) 5.
An encoding circuit 38 for encoding 0 is provided. The encoding circuit 38 does not necessarily need to be provided inside the apparatus depending on the recording code. In this embodiment, (2, 11) RLL coding is performed. The synthesizing circuit 35 synthesizes the synchronizing signal from the synchronizing signal generating circuit 37, the encoded data from the encoding circuit 38, and the pseudo data from the pseudo data generating circuit 39 according to the timing signal of the timing generating circuit 40, and records the recording in recording units. To generate encoded composite data 51 to be processed. The pulse conversion circuit 34 converts the encoded composite data 51 into a recording pulse 53 with a polarity according to the random signal 52 emitted from the random signal generation circuit 36. Here, the inversion of the polarity according to the random signal 52 is performed for each recording unit. This timing is controlled by a timing signal 54 from a timing generation circuit. The recording pulse generated in this way is converted into a pulse suitable for the actual recording / reproducing head and recording medium by the recording pulse shaping circuit 31, and is applied to the recording medium 8 by the recording / reproducing head 32 to perform recording. A mark is formed. Referring to FIG. 1, the relationship between a recording mark finally formed by this embodiment and encoded data will be described. The encoded data string “001000” in FIG.
"01001100001000100" is converted into A: "0011111000011111" by the pulse conversion circuit 34.
0000111 "or B:" 11000001110
00001111000 "recording pulse, NRZI
-NRZ conversion is performed. The encoded data sequence is, for example, a pulse 51 having a high level at "1" as shown in FIG.
The pulse conversion circuit forms a pulse 53A or a pulse 53B whose polarity is inverted from the pulse 53A from the pulse 51. When recording is performed after these recording pulses 53 are shaped into divided pulses or the like by the recording pulse shaping circuit 31, as shown in FIG. 1A, the mark 6 corresponds to the portion 1 in the recording pulse. A space 7 is formed on the recording medium corresponding to the portion 0 in the drawing. That is, in A and B, the space between the mark 6 and the mark is reversed. As described above, even if the mark and the space are reversed, there is no problem in reproduction. Because
At the time of reproduction, a signal corresponding to both ends of the recording mark 6, that is, a boundary portion between the mark 6 and the space 7 is detected, so that the reproduced data is reproduced as the same coded data for both A and B. FIG. 9 shows an example of the pulse conversion circuit 34 of this embodiment. When the timing signal 54 goes high, 2
When the valued random signal 52 is selected as the initial value of the exclusive OR circuit, and when the timing signal 54 goes low thereafter, the encoded combined data including the encoded data string 51 and the output of the exclusive OR circuit are output. As the exclusive OR, the recording pulse signal 53A or 53B is output. In this embodiment, in addition to the polarity inversion, the recording start position is randomly shifted. The timing control of this random shift is performed by the timing generation circuit 40 controlling the timing of the output from the synthesis circuit 35. The timing generation circuit 40 randomly shifts the recording start timing by a signal from the random signal generation circuit 36. FIG. 8 shows a jitter characteristic when the same data is repeatedly recorded on the same recording medium according to the present embodiment. 81 is a case where the shift of the recording start position is 2 bytes and there is no polarity inversion, and 82 is a case where the shift of the recording start position is 2 bytes.
This shows the case where the polarity is inverted in the case of bytes. Here, the jitter is obtained by normalizing the standard deviation of the time lag between the reproduction clock and the reproduction data in the case where the same data is repeatedly recorded and then reproduced, by the reproduction detection window width. Even when the shift of the recording start position is as small as 2 bytes, by performing the polarity inversion as in the present embodiment, the number of rewritable times is greatly improved as compared with the case of recording by the conventional apparatus (with no polarity inversion). You can see that it is. Here, the shortest mark length was 0.6 μm, and the recording / reproducing spot diameter was 0.9 μm. As described above, in this embodiment, the mark 6 having the first optical property and the space 7 having the second optical property are formed on the recording medium, and the boundary between the mark and the space is formed. Is a recording method of recording information in correspondence with a binary code of "1" or "0". Even if the same information is recorded a plurality of times, a boundary corresponding to a specific binary code in the information is recorded. Is controlled so that both the boundary that changes from a mark to a space and the boundary that changes from a space to a mark appear in multiple recordings, thereby improving the reliability of the recording medium. it can. Embodiment 2 Another embodiment of the present invention will be described.
The same information recording device as that shown in FIG. 5 was used. That is, it has a recording / reproducing head 32 for recording / reproducing on the recording medium 8, a reproduction signal from the recording / reproducing head 32 is detected by a detection circuit 33 and the detection signal is reproduced by a reproduction circuit 41. The reproduction circuit 41 includes at least an identification information detection circuit 42 for detecting identification information on a medium. The timing generation circuit 40 controls various timings related to the recording operation according to the identification information signal from the identification information detection circuit 42. Further, the device of this embodiment has at least a random signal generation circuit 36. As a method of generating a random signal by the random signal generation circuit 36, for example, a pseudo random sequence generator may be provided inside the random signal generation circuit 36, or a random signal may be generated from a signal asynchronous with the recording / reproduction operation such as time. May be generated.
The apparatus according to the present embodiment further includes recording information (recording data) 5.
An encoding circuit 38 for encoding 0 is provided. The encoding circuit 38 does not necessarily need to be provided inside the apparatus depending on the recording code. In this embodiment, (2, 11) RLL coding is performed. The synthesizing circuit 35 synthesizes the synchronizing signal from the synchronizing signal generating circuit 37, the encoded data from the encoding circuit 38, and the pseudo data from the pseudo data generating circuit 39 according to the timing signal of the timing generating circuit 40, and records the recording in recording units. To generate encoded composite data 51 to be processed. The synchronization signal generation circuit changes the length of the synchronization signal according to the random signal generated by the random signal generation circuit 36.
In addition, the pseudo data generation circuit includes a random signal generation circuit 3.
6, the length of the pseudo data is changed in accordance with the random signal issued from. The pulse conversion circuit 34 converts the encoded composite data 51 into a recording pulse 53 with a specific polarity. That is, the polarity is not inverted as in the above embodiment. The recording pulse generated in this way is converted into a pulse suitable for the actual recording / reproducing head and recording medium by the recording pulse shaping circuit 31, and is applied to the recording medium 8 by the recording / reproducing head 32 to perform recording. A mark is formed. In this embodiment, the recording information is arranged on the recording medium as shown in FIG. That is, the synchronization signal section 22 is arranged from a position which is substantially constant distance from the identification information 24 indicating the head of the sector 21, and the length of the synchronization signal section 22 is different for each sector 21. After the synchronization information section, the information recording section 23 and the pseudo data section 25 are arranged in this order. The length of the synchronization signal portion changes according to the random signal generated by the random signal generation circuit 36. The length of the pseudo data is changed by the pseudo data generation circuit in accordance with the random signal generated by the random signal generation circuit 36. At this time, the length from the beginning of the synchronization signal portion to the rear end of the pseudo data portion is substantially constant. I am trying to become. By doing so, even if the data in the information recording unit is the same, the position of the information recording unit 23 can be moved back and forth, so that the position of the information recording unit 23 on the medium can be changed. Since the number of recordings changes randomly and the integrated recording count of the mark portion and the space portion becomes uniform irrespective of the position of the medium, the change of the recording medium due to repeated recording is made uniform,
As in the conventional example, the number of times of rewriting can be improved. On this occasion,
Unlike the conventional example, the recording start position and the recording end position are at substantially the same position. For this reason, even if the shift amount of the information recording unit 23 is increased to about 30 to 100 bytes, the influence of the change in the recording / reproducing characteristics near the recording start point and the recording end point does not spread to the recording unit. Therefore, it is easy to increase the shift of the information recording unit 23, and the number of rewritable times is improved. As described above, in the present embodiment, in the information recording method for forming a recording mark in the data area of the recording medium and recording the information by associating the information with both ends of the recording mark, First and second adjustment areas are provided before and after the data area, and the lengths of the first and second adjustment areas are changed to shift the position of the data area and to transmit the same information a plurality of times. At the time of recording, the recording is performed such that the arrangement of the recording mark and the space portion between the recording marks is reversed in a plurality of recording mark arrays recorded on the recording medium corresponding to the same information. << Embodiment 3 >> Using the same apparatus as in Embodiment 2, when changing the length of the synchronization information,
The length of the first synchronization information section 221 (VFO section) in which marks 6 and spaces 7 having the same length are alternately and repeatedly arranged, and the polarity at the end are changed. Specifically, the polarity is automatically switched depending on whether the total number of marks and spaces is an even number or an odd number. Further, a second synchronization information section 222 (SYNC section) is provided after the first synchronization information section 221.
The pattern of the second synchronization information section 222 is fixed, but the polarity changes depending on the polarity at the end of the first synchronization information section 221 described above. FIGS. 3A and 3B show examples in which the sum of marks and spaces in the first synchronization information section 221 is odd, and FIG.
Shows an example of an even number. In this embodiment, since the polarity can be inverted without using a polarity inversion circuit, the configuration of the recording apparatus is simplified. Information recording unit 2
3 can be shifted, so that the uniformity of the total number of recording times of the mark portion and the space portion is further improved.
The change of the recording medium due to the repetitive recording is further uniformed, and the number of rewrites that can be repeatedly performed is further improved as compared with the first embodiment. Embodiment 4 Using the same apparatus as in Embodiment 3, the length of the first synchronization information section 221 is changed at random, and at the same time, the recording start position is changed based on a random signal ( (See FIG. 4). In this case, the length of the shift of the recording start point is substantially the same as the length of the mark in the first synchronization information section 221 (up to 1/4 byte). As a result, the total number of recording times of the mark portion and the space portion in the synchronization information portion becomes uniform irrespective of the position of the medium, so that the number of rewrites that can be repeated is further improved as compared with the third embodiment. Since the shift amount of the recording start position is sufficiently small, the recording start position can be regarded as the same from the viewpoint of the change in the recording / reproducing characteristics near the recording start point, so that there is no adverse effect due to the shift as in the conventional example. By recording while reversing the mark portion and the space portion randomly each time the repetition is performed, the total number of recordings of the mark portion and the space portion on the medium when rewriting is performed repeatedly is independent of the position of the medium. Since the recording medium becomes uniform, the change of the recording medium due to the repetitive recording is made uniform, and the number of times of rewriting can be remarkably improved. This does not reduce the recording efficiency of information at all. In addition, since the position of the information recording section on the medium changes randomly by changing the length of the synchronization signal section at the head of the information recording section at random, the cumulative recording count of the mark section and the space section is reduced by the medium. Since the recording medium becomes uniform irrespective of the position, the change of the recording medium due to the repetitive recording is made uniform, and the number of rewrites that can be repeated is improved. As described above, the present invention can improve the life of a recording medium without impairing the storage capacity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram showing an example of an information recording method according to the present invention. FIG. 2 is a plan view showing an example of the information recording method of the present invention. FIG. 3 is a plan view showing an example of the information recording method of the present invention. FIG. 4 is a plan view showing an example of the information recording method of the present invention. FIG. 5 is a block diagram of the information recording apparatus of the present invention. FIG. 6 is a plan view showing an example of a conventional information recording method. FIG. 7 is a graph showing the effects and problems of a conventional information recording method. FIG. 8 is a graph showing the effect of the information recording method of the present invention. FIG. 9 is a circuit configuration diagram of a part of the information recording apparatus of the present invention. [Description of Signs] 6: mark, 7: space, 8: recording medium, 21: sector, 22: synchronization information section, 221: first synchronization information section,
222: second synchronization information section, 23: recording information section, 24:
Identification information section, 25: pseudo data section, 31: recording pulse shaping circuit, 32: recording / reproducing head, 33: detection circuit, 3
4: recording pulse generation circuit, 35: synthesis circuit, 36: random signal generation circuit, 37: synchronization signal generation circuit, 38: encoding circuit, 39: pseudo data generation circuit, 40: timing generation circuit, 41: reproduction circuit, 42: identification information detection circuit, 50: recording data, 51: encoded combined data, 5
2: random signal, 53: recording pulse, 54: timing signal

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-219022 (JP, A) JP-A-8-7276 (JP, A) JP-A-9-320054 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G11B ^7/ 00-7/013

Claims (1)

(57) [Claim 1] In an information recording method in which a mark having a physical property different from that of another part is formed and information is recorded by associating information with both ends of the mark, A first adjustment area including a plurality of marks and a second adjustment area are arranged at the head of a recording unit, and the number of marks in the first adjustment area is changed each time information is rewritten by changing the number of marks in the first adjustment area . of the rewritable recording by changing the length of the substantially random adjustment area, the information recording start position is changed substantially randomly, a polarity of the second adjusting region, before
The first adjustment area is changed according to the polarity at the end of the first adjustment area.
An information recording method, wherein information is recorded in a recording information section behind the second adjustment area .