JP2006344369A - Optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information recording technique, with which the recording strategy can be regulated by a small number of parameters and which can correspond to a plurality of scanning line speeds. <P>SOLUTION: In this optical information recording medium, wherein a recording mark corresponding to a time length n<SB>1</SB>×T, when n=n<SB>1</SB>=2m (m denotes a natural number of 2 or larger) and a recording mark corresponding to a time length n<SB>2</SB>×T, when n=n<SB>2</SB>=2m+1 are formed by m pieces of multi-pulses having irradiation power Pw, when irradiation time of an i-th pulse (i denotes a natural number of 1 to (m-1)) is expressed by T<SB>on</SB>(n, i), parameters of the recording strategy are pre-formatted, including the case T<SB>on</SB>=(n, i)=constant Tmp and T<SB>on</SB>(n<SB>1</SB>, i)=T<SB>on</SB>(n<SB>2</SB>, i) are satisfied, when n≥4, the case the irradiation period of the irradiation power Pw is larger than 2T, when n=n<SB>2</SB>, and ones that are different between time widths n=n<SB>1</SB>and n=n<SB>2</SB>between pulses of the irradiation power Pw. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a recordable optical information recording medium, and more particularly to a phase change optical information recording medium such as a CD-RW, a DVD-RAM, a DVD-RW, and a DVD + RW.

  In recent years, the demand for high-speed recording of optical information recording media has increased. In particular, in the case of a disk-shaped optical recording medium, since the recording / reproducing speed can be increased by increasing the rotational speed, the speed is increasing. Among optical discs, optical recording media that can be recorded only by the intensity modulation of the light irradiated during recording can reduce the price of the medium and the recording device due to the simplicity of the recording mechanism, and at the same time, the intensity of reproduction is also modulated. Because of the use of light, it has become widespread because high compatibility with read-only devices can be secured, and the demand for higher density and higher speed recording has increased due to the recent increase in capacity of electronic information. .

  Among such optical discs, those using a phase change material have become mainstream because they can be rewritten many times. In the case of an optical disk using a phase change material, recording is performed by creating a rapid cooling state and a slow cooling state of the recording layer material by intensity modulation of the irradiated light beam. The recording layer material becomes amorphous when it is rapidly cooled, and becomes crystalline when it is slowly cooled. Since optical properties are different between amorphous and crystalline, optical information can be recorded.

  Since the recording principle uses such a complicated mechanism of “rapid cooling” and “slow cooling” of the recording layer material, as disclosed in Japanese Patent Laid-Open No. 9-219021 for high-speed recording, This is performed by irradiating the medium with recording light that is pulse-divided and intensity-modulated into three values. As such a recording method, JP-A-9-138947, JP-A-9-219021, Recordable Comact Disc Systems Part III (commonly known as Orange Book Part III) version 2.0, volume 2 version 1.1, DVD + RW Basic Format Specifications. Examples described in version 1.1 can be exemplified.

  In these recording methods, when a mark as shown in FIG. 24 (a) is used as data in which a mark portion is high and a non-mark portion is low as shown in FIG. 24 (b), the time length is fundamental. This is applied when a mark length that is an integral multiple of the clock period T and an inter-mark recording method are used. That is, the recorded mark has a time length nT when the natural number n is used. The range of the natural number n varies depending on the modulation method, and is 3 to 11 in the compact disc CD system, and 3 to 11 and 14 in the DVD system. FIG. 24 illustrates the case where n = 6.

  In the above prior art, as shown in FIG. 24C, m multi-pulses are irradiated to form a mark having a temporal length nT. m depends on n, and the relationship is m = n−1 or m = n−2. This is because the minimum value of n is 3 for CD and DVD. Further, the pulse irradiation period, that is, the rising period of each pulse is 1T as shown in FIG. The same applies to the case of m = n−2, and the pulse irradiation period is 1T as shown in FIG. However, in any case, the period and width of the first pulse are uniquely set.

  This recording method is characterized by being able to cope with the addition of one pulse when the mark length is increased by 1T, and is a recording method very suitable for the mark length recording method.

  However, when the recording speed is increased, the basic clock frequency is increased, and the CD-RW corresponding to 24 × speed is approximately 104 MHz, and the DVD-RW corresponding to 5 × and DVD + RW is approximately 131 MHz. Therefore, the conventional recording method (recording strategy) Then, the proportion of the time required for rising and falling in the pulse irradiation time increases, and the effective irradiation light energy, that is, the integrated value decreases.

  An example is shown in FIG. In contrast to the ideal irradiation waveform indicated by the dotted line, the actual light emission waveform requires time to rise and fall, so that it is not a rectangle as shown by the dotted line in FIG. It becomes like this. Further, as shown in FIG. 25B, the basic clock period becomes higher and the ratio of the rising and falling times becomes higher, and the sufficiently high peak power Pw and the sufficiently low bottom power Pb cannot be secured. That is, the peak power Pw is decreased by ΔPw, and the bottom power Pb is increased by ΔPb. By reducing the peak power Pw, the volume rising to a temperature sufficient for amorphization is reduced, and when the bottom power Pb is not sufficiently low, rapid cooling cannot be performed and recrystallization is promoted. As a result, the volume of the amorphous region is reduced. Accordingly, the reproduction signal amplitude is lowered, and the reproduction reliability is remarkably lowered.

  In order to solve such a phenomenon, a light source (laser diode and its driving device) capable of light emission with a short rise and fall time is required. In order to cope with a frequency exceeding 100 MHz, the rise, The time required for the fall needs to be 1 ns or less, which is very difficult.

  Therefore, as a technique for performing high-speed recording with the current light emitting light source, it has been proposed to cope with the problem by reducing the recording pulse by the method disclosed in Japanese Patent Laid-Open No. 9-134525 and US Pat. No. 5,732,062. Yes. According to this technique, in order to form a mark of n times the basic clock period T, that is, an nT mark in the past, (n-1) pulses are irradiated to form n. When n is an even number, that is, n = 2m, a mark is formed by m pulse irradiation, and when n is an odd number, that is, n = 2m + 1, a mark is formed by m pulse irradiation. That is, in the EFM modulation method adopted in the CD-RW, n is a natural number from 3 to 11, and therefore, n = 3, 4, 5, 6, 7, 8, 9, 10, and 11 are irradiated. The number of pulses was 2, 3, 4, 5, 6, 7, 8, 9, 10. On the other hand, in JP-A-9-134525 and US Pat. No. 5,732,062, the number of irradiation pulses is 1,2 for n = 3,4,5,6,7,8,9,10,11. , 2, 3, 3, 4, 4, 5, 5 and the number of irradiation pulses is approximately half. Accordingly, as shown in FIG. 25 (c), the irradiation time of one pulse is approximately doubled corresponding to 1T from 0.5T corresponding to (n-1), and therefore the influence of the rise and fall times. It becomes difficult to receive.

  On the other hand, since the recording marks 2mT and (2m + 1) T having different lengths are formed by the same number of m pulse irradiations, the irradiation cycle cannot be made constant. Therefore, only the recording mark of n = 2m is performed by shortening the irradiation time (P = Pw time) and cooling time (P = Pb time) of an arbitrary pulse.

  Japanese Patent Laid-Open No. 2001-331936 discloses a recording method using m multi-pulses in order to form a recording mark having a time length nT, and the ratio n / m ≧ 1.25 and the above-described method. As in the case of Japanese Patent Laid-Open No. 9-134525, a technique for recording recording marks having different lengths of n = 2m and n = 2m + 1 by m pulse irradiation of the same number is described in detail. The method of adjusting the length by the same number of pulse irradiations is made possible by adjusting the irradiation time and cooling time of the first pulse and the irradiation time and cooling time of the final pulse.

  However, basically, the irradiation time and cooling time of all pulses are defined for each mark length. 69 parameters are required for EFM (Eight to Fourteen Modulation) used in compact discs, and 77 for EFM + (a type of 8-16 modulation) used for DVDs. Parameter is required. In order to reduce the number of parameters to be defined, a method of unifying the irradiation time of the first pulse of m ≧ 3 regardless of n, the irradiation time of intermediate pulses (pulses excluding the first pulse and final pulse) when m ≧ 3 A method for unifying the cooling time and the like has been proposed. However, when m = 1 and 2, that is, when n ≦ 5, it is necessary to set parameters independently for each. Therefore, a very large number of parameters are required to define the recording light emission waveform (recording strategy). Further, when the recording speed (scanning speed) is different, a different pattern is required for each recording speed, and as a parameter that can be unified, an irradiation time of P = Pw (in a relative time with respect to a clock cycle that changes depending on the recording speed) It can be solved by making the actual pulse width) constant regardless of the recording speed.

In the case of a write once or rewritable optical disk represented by CD-R / RW and DVD + RW / R, it is common to preformat parameters relating to the recording conditions of the disk on the disk itself. Examples of a method for recording disc information as a preformat include information recorded in CD-R / RW ATIP (Absolute Time in Pregroove) Extra Informations and DVD + RW / R ADIP (Address in Pregroove) Physical Information. These information includes the basic conditions such as the type of disc and the standard version to be complied with, as well as the parameters necessary for calculating the recordable scanning speed, optimum recording power, and optimum recording power in test recording. And parameters that define the optimum recording strategy are recorded. The parameters that define the optimum recording strategy are ε (= Pe / Pw) and Strategy Optimization (dT _top , dT _era ) according to the CD-RW standard specification, and T _top according to the DVD + RW standard specification. , DT _top , T _mp , dT _era , ε ₁ , ε ₂ .

  The information recording apparatus reads these pieces of information when recording on the disc and determines a recording strategy. For this reason, it is preferable that the parameters are determined in detail because the recording apparatus can set an accurate recording strategy, but there is a drawback that the amount of information increases. In particular, in the case of a CD-R / RW system, the amount of information (capacity) that can be preformatted is limited, and in the case of a CD-RW, only 21 bits × 6 = 126 bits of information can be entered. When adding more information, an area newly defined as an unused area on the innermost or outermost part of the disc, for example, an XAA (Extra Additional Information Area) adopted in CD-R Multi-speed is used. It is necessary to use or record information in a pre-pit or the like.

  In the recording device, these preformatted disc information is read into the device at the time of recording operation as described above, and an optimum recording strategy is set. However, if a large number of parameters are set for each disc, the processing contents are complicated. Therefore, the strategy generation circuit becomes complicated.

  For these reasons, it is desired that the strategy definition be accurate with few parameters.

  An object of the present invention is not to use a recording method that uses a large number of parameters to define a complex recording strategy corresponding to high-speed recording, but to set an optimal strategy that can support a plurality of scanning line velocities only by defining a few parameters. It is to provide information recording technology that can be used.

The present invention relates to an optical information recording medium in which information is recorded by a mark length recording method corresponding to nT in which the time length of a recording mark is n times (n is a natural number) the basic clock period T. n = n ₁ = A recording mark corresponding to the temporal length n ₁ · T in the case of 2m (m is a natural number of 2 or more) and a recording mark corresponding to the temporal length n ₂ · T in the case of n = n ₂ = 2m + 1 When the irradiation time of the i-th pulse (i is a natural number of 1 to (m−1)) is represented by _Ton (n, i) when forming with m multi-pulses of irradiation power Pw, n ≧ 4 Where T _on (n, i) = constant T _mp and T _on (n ₁ , i) = T _on (n ₂ , i), where n = n ₂ Including Pw irradiation period greater than 2T, between pulses of the irradiation power Pw And wherein the when the time width recording strategy including those different in the case of the n = n ₂ when n = n ₁ is used, the parameters for setting the irradiation power Pw is preformatted An optical information recording medium is provided.

  In the present invention, the preformatted parameter is preferably a parameter for setting a minimum scanning speed when the recording strategy is used. Further, the preformatted parameter in the present invention is preferably a parameter for setting the time width of the irradiation power Pw.

According to the present invention, the total width of the high pulse and the low pulse of the multi-pulse when recording the mark length corresponding to the time length nT is shorter than the time length nT, and the even number n is a reference. In this case, when the reference n increases by 2, the number of high pulses and low pulses increases by 1 to record the corresponding mark length, and when n increases by 1, the corresponding mark length is recorded. high pulse and the number of low pulses for since the respective the number of high pulses and low pulses for recording a mark length corresponding to n the same basic clock cycle irradiation time T _on per pulse T Therefore, the influence of the time required for the rise of light emission can be reduced, a high modulation degree and low jitter can be realized with a low recording power, and when n increases by 1, it exists between high pulses. Small Since the width of at least one low pulse is longer than the width of one low pulse existing between the high pulses for recording the mark length corresponding to n, the parameters having little influence on the characteristics are unified, The recording strategy can be accurately defined with a small number of parameters.

  An embodiment of the present invention will be described with reference to FIGS.

  The present embodiment is applied to an information recording method and an information recording apparatus (including an information reproducing apparatus) for an optical information recording medium that can be recorded, erased or rewritten by intensity modulation of irradiation light, particularly a phase change type optical information recording medium. Applied.

  Recording on an optical information recording medium is performed by irradiating and scanning an intensity-modulated light beam to form a recording mark on the medium. The recording mark is a region having different optical characteristics due to light irradiation, and is formed in the recording layer of the medium. The information recording apparatus and the information reproducing apparatus reproduce information by using the difference in optical characteristics of the recording mark portion. The state of the recording mark varies depending on the type of the recording layer material. In the case of a magnetic recording layer material, the region has different magnetic orientation, and in the case of a phase change material, the region has a different phase. In an optical information recording medium using a phase change material, which is the most common rewritable optical information recording medium, a material having a crystalline phase and an amorphous phase (amorphous layer) is used as a recording layer material. . Examples of such phase change recording layer materials include SbTe alloys, GeSbTe alloys, AgInSbTe alloys, and GaGeSbTe alloys. Since the phase change recording layer material has optical characteristics that are greatly different between the crystalline phase and the amorphous phase, it is possible to record information by forming amorphous phase marks in the crystalline phase. Further, when the crystalline phase and the amorphous phase undergo a reversible phase transition, a rewritable optical information recording medium is obtained.

[Information recording method]
In order to form an amorphous mark in the crystal phase, it is performed by irradiating and scanning light condensed on the recording layer or in the vicinity of the recording layer. At this time, as described above, it is performed by irradiating an intensity-modulated light beam. FIG. 1 and FIG. 2 show an emission waveform (recording strategy) of an intensity modulation method that is a premise of the present embodiment. FIG. 2A shows information DATA to be recorded. In the information recording method of the present embodiment, information is recorded by a recording mark length / inter-mark length modulation method in which PWM (Pulse Width Modulation) is applied to an optical information recording medium. In this recording method, information can be recorded by controlling the length of the recording mark and the length between the marks in units of the basic clock period T. Since the recording density can be made higher than that of the mark position modulation method which is one of the recording methods of the optical information recording medium, it is characterized in that the recording density can be increased and is adopted in CD and DD (Double Density) CD. This is a modulation method employed in an optical disk such as EFM + employed in EFM and DVD. In the recording mark length and inter-mark length modulation system, it is important to accurately control the recording mark length and the inter-mark length (hereinafter, space length). In these modulation schemes, the recording mark length and space length are both nT (n is a natural number) with respect to the basic clock period T.

  In FIG. 2A, the horizontal axis corresponds to the time length, the vertical axis represents information to be recorded, and the high level corresponds to the recording mark. Since FIG.1 and FIG.2 (a) has shown the case of EFM or EFM + as an example, n is 3-11 and 14. FIG. Among these, the recording strategies in the case of n = 3, 4, 5, 10, 11 are extracted and shown in FIGS. At this time, the horizontal axis corresponds to the time length as in FIG. 2A, and the vertical axis represents the intensity (irradiation power) P of the irradiated light. The intensity of the irradiated light takes three values of Pw, Pe, and Pb, and the relationship is Pw> Pe> Pb. Pw is called recording power, Pe is called erasing power, and Pb is called bias power. When the light beam is irradiated with P = Pe, the phase change recording layer is in a crystalline state. That is, the marks are erased (recorded between the marks). On the other hand, when irradiated with intensity modulation of P = Pw and P = Pb, the phase change recording layer is in an amorphous state. That is, a recording mark is formed. Pw, Pe, and Pb are determined from the thermal characteristics and optical characteristics of the recording phase material of the medium. The erasing power Pe is preferably in the range of 0.2 Pw to 0.6 Pw, and the bias power Pb is 0 to 0. It is preferably in the range of 0.1 Pw.

The recording strategy of the present embodiment uses m P = Pw on-pulses and P = Pb off-pulses to record a recording mark having a temporal length nT. The relationship between n and m is as follows. When n is an even number n1, the relationship n1 = 2m must be established, and when n is an odd number n2, the relationship n2 = 2m + 1 must be established. That is, each time the time length nT is increased by 2T, a recording mark is formed by a multi-pulse in which the power Pw on-pulse and the power Pb off-pulse are each increased by one. Here, i-th taking P = Pw when forming the mark of the time length nT (i = 1, ..., m) represents the pulse width of the (irradiation time) _T on (n, i) and. Compared with the recording strategy of m = n−1 employed in the conventional CD-RW, DVD-RW, and DVD + RW, the pulse period is approximately doubled, so that T _on / T can be increased. . Therefore, the influence of the rise and fall times of the power P can be made relatively low, and high-speed recording with a short basic clock period T can be handled.

Although the scope of the irradiation time _{T on} is arbitrary, the range of 0.5T~1.5T is preferred. If the time is shorter than 0.5T, the irradiation time is too short to give sufficient energy to the recording layer. As a result, the width of the recording mark (mark length in the direction perpendicular to the scanning direction) decreases, and the amplitude of the recording signal Becomes lower, the modulation degree is lowered, and the reproduction reliability is low. When the irradiation time T _on is longer than 1.5T, since the time the power P = Pb becomes relatively short, it becomes difficult to maintain the rapid cooling. Therefore, energy can be sufficiently applied to the recording layer, but the recording mark becomes small due to recrystallization. Furthermore, since the absolute amount of energy applied to the medium becomes large, if a large number of times of recording / rewriting (overwriting) is performed, thermal damage occurs in the recording layer and its surroundings, resulting in a decrease in reliability. .

In the case of such a strategy, the irradiation time of the mth pulse, that is, T _on (n, m) has the greatest influence on the mark length to be recorded. In particular, when n = n2 (odd number), it becomes more prominent. Shows the relationship between T _{on (n,} m) as the shift amount of the mark length mark Deviation in FIG. The mark deviation D (n) is represented by D (n) = L (n) −nT, where L (n) is the reproduced mark length. That is, when D (n) = 0, there is no difference between the logical mark length and the actual recording mark length, so that it can be said that the recording mark is good. It can be seen that when n is an odd number (n = 2m + 1), the D dependence of T _on (n, m) is greater than when n is an even number (n = 2m). This is caused by recording different mark lengths of n ₁ · T and n ₂ · T with the same number of m pulses. This is because the n ₂ · T mark is longer by 1T than the n ₁ · T mark, and it is necessary to correct the correction by the irradiation time of the final pulse and the cycle of the pulse.

  On the other hand, it is known that the pulse irradiation time other than the last pulse has little influence on the length of the recording mark. FIG. 4 shows the deviation dependence of the final pulse (pulses other than the m-th pulse) width. Regardless of whether n is an odd number (n = 2m + 1) or an even number (n = 2m), the dependence is small and there is no clear difference between the odd number and the even number. Therefore, the irradiation strategy Ton other than the irradiation time of the mth final pulse can unify the recording strategy regardless of whether n is an even number or an odd number.

That is, when 1 ≦ i ≦ m−1,
T _on (n1, i) = T _on (n2, i)
Is possible.

Furthermore, when two or more pulses are used, that is, when m ≧ 2 and n ≧ 4, it is possible to unify all the pulses regardless of n and i. That is,
T _on (n, i) = constant T _mp (n ≧ 4, 1 ≦ i ≦ m−1)
It can be. At this time, the constant T _mp is preferably 0.5T to 1.5T.

Further, the final pulse when n is an even number has a small influence on the recording mark. n is an even number, i.e., m-th pulse _T on (n1, m) in the case of n = n1 also irrespective of the _{n 1,}
T _on (n ₁ , m) = T _mp
It can be. These matters are the same when n = 14, which belongs to the case where n is an even number.

On the other hand, the final pulse width when n is an odd number, that is, n = n2, can be unified regardless of n2 when m ≧ 2, that is, n2 ≧ 5. That is,
T _on (n ₂ , m) = T _1p (n2 ≧ 5, m ≧ 2)
It is. This is because the dependency of D (n ₂ ) on the final pulse width is almost constant regardless of n2. However, if a pulse width having the same length as n ₁ is set, odd marks tend to always be shorter than even marks as shown in FIG. Therefore, in order to align the deviation of the deviation and _{n 2} · T mark _{n 1} · T mark _{D 0} is, _{n 2} · T marks the last pulse _T on _(n 2, m) a _T on _(n 1, m ) = _Tmp needs to be longer than δT by δT. That is,
T _on (n ₂ , m) = T _on (n ₁ , m) + δT
Therefore,
T _1p = T _mp + δT
It becomes. The optimum value of δ is selected depending on the thermal characteristics of the recording layer of the optical information recording medium, but is preferably in the range of 0 to 1.0, more preferably in the range of 0 to 0.5. If δ exceeds 1.0, the length of the odd mark becomes too long. On the other hand, if it exceeds 0.5, the effect due to the fluctuation of the power Pw of the final pulse becomes too great, so the dependency of the mark length on the recording power Pw is greatly different from the case where n is an even number, and the recording power margin is extremely narrow. Tend to be.

Consequently, n can be any irradiation time T _on of all the pulses other than the last pulse in the case of an odd number the same (= T _mp).

  Incidentally, in the recording mark length and inter-mark length modulation recording, the space length is important as well as the mark length. This is because, in the binarized information, the mark and the space are treated equally and only the boundary is a singular point. Therefore, control of the space length is required, but once the mark length is determined, the space length is inevitably determined. However, the variation greatly depends on the front and rear marks. That is, the space length after the recording mark with an odd number n may be different from the space length after the recording mark with an even number n.

In order to optimize these, it is possible to control the deviation start time Td2 from the data end time of the rising start time T _d1 of the first pulse and the rising start time P = Pe after the m-th off pulse. Become. In particular, since the influence of the shift time T _{d2 on} the space jitter is large, it is necessary to set an optimal value for the shift time T _d2 for each mark length. This is because the shift time _Td2 is a parameter that determines the start time of the space following the recording mark.

However, the time T _{d2 in} the case of a recording mark of m ≧ 2 can be unified. The range is preferably in the range of -T to T, more preferably in the range of -0.5T to 0.75T.

On the other hand, the time T _d1 similarly affects the space jitter. However, since T _d1 and T _d2 are relative and the other is dependent, the optimization is performed simultaneously with T _d2. Can be unified for all n. The time T _d1 is preferably in the range of 0T to 1T.

So far, unification of many parameters has been discussed in order to define the recording strategy. However, regarding the 3T mark which is the minimum mark, parameters other than the rise time Td1 need to be set independently. This is clearly different from the strategy pattern of m ≧ 2, since only the 3T mark is m = 1 and the pulse is the first pulse at the same time as the last pulse (first pulse). Therefore, the pulse irradiation time T _on (3, 1) needs to be set independently,
T _on (3,1) = T _mp '
It is. T _mp ′ is optimized by the thermal characteristics and optical characteristics of the recording layer material, the scanning linear velocity at the time of recording, and the clock cycle, and the range is preferably in the range of 0.5T to 2.0T. Similarly, it is necessary that those shift time _{T d2} be n = 3 to be set independently, the range is preferably in the range of -T～T, more preferably in the range of -0.5T~0.75T is there.

  Incidentally, the pulse irradiation period affects the uniformity of the mark shape. When the pulse irradiation period is not uniform, the mark shape is easily distorted, and as a result, the reproduced signal is also distorted, which tends to deteriorate the jitter. This tendency becomes remarkable when the pulse irradiation time Tmp is small, that is, when the pulse width at which P = Pw is small and the time at which P = Pb is relatively long.

  The pulse irradiation cycle is preferably uniform, and more preferably the cycle is approximately nT / m. However, the period here means an average period and is not an individual period. That is, for example, when recording a mark of nT = 11T, the average period of five pulses is nT / m = 11T / 5 = 2.2T, and all the periods need to be 2.2. There is no. For example, the period between the first pulse and the second pulse is 2.4T, the period from the second pulse to the fourth pulse is 2.0T, and the period from the fourth pulse to the fifth pulse is 2.4T. In this case, the average period is 2.2T. However, in order to improve the uniformity, it is best to set the period to nT / m. In addition, since setting the pulse irradiation period individually means that the parameters for defining the recording strategy increase, it is preferable to unify the periods. In this case, the cycle when n is an even number is always 2T, but the cycle when n is an odd number of 5 or more gradually approaches 2T as n increases. That is, as shown in FIG. 5, the period when n is an odd number of 5 or more is nT / m = 2.5T, nT / m = 2.33T, nT / m = 2.25T, nT / m = 2. .2T decreases as it approaches 2T as n increases.

Further, when attention is paid to the irradiation time T _off (n, m) of the final off pulse of the power Pb added after the irradiation of the final pulse, as described above, the time T _d2 for advancing the rising of the final off pulse to the power Pe is as described above. As shown in FIG. 6, when n is an even number, the irradiation time T _off (n, m) is constant regardless of the value of n, and when n is an odd number, as shown in FIG. irradiation time _T off with increasing (n, m) is the recording strategy to decrease to asymptotic to the irradiation time _T off of an even number (n, m).

As described above, the optimum recording strategy used in the information recording method of the present embodiment is the following six parameters T _mp
T _mp '
δ
T _d1
T _d2
T _d2 '
It can be described by. This is a clearly defined method compared to the conventional method of defining 69 parameters for EFM and 77 parameters for EFM +. Furthermore, since the time T _d1 is dependent on the time T _d2 and can be regarded as a fixed value, it can be substantially described by five types of parameters.

  A recording strategy defined using such parameters is shown in FIG.

By the way, when such a recording strategy is applied and the recording speed (scanning speed) is changed, the irradiation time T _mp and T _mp ′ can be changed with respect to the scanning linear speed v at the time of recording. Is possible. Other parameters can be constant with respect to the basic clock period T (v). That is, δ / T (v), T _d1 / T (v), T _d2 / T (v), and T _d2 ′ / T (v) normalized by the basic clock period T (v) are the recording speed (scanning speed). ) Is constant regardless of.

The relationship between T (v) and v is T (v) = L ₀ / v when the linear density is constant where the amount of information per unit length in the scanning direction is constant. Here, L ₀ corresponds to the length on the optical information recording medium corresponding to the basic clock period T, and is generally called the channel bit length. In the case of DVD, L ₀ = 0.133 μm, and in the case of CD, L ₀ = 0.278 μm or 0.324 μm. That is, when the scanning speed is doubled, the basic clock period T is halved.

Thus, it is preferable that T _mp (v) / T (v) and T _mp ′ (v) / T (v) become smaller when the scanning speed is changed. That is, when considering the case where the scanning speed is v = v _L and v = v _H (where v _L <v _H ), the relative time with respect to the basic clock period T (v) is:
_{T mp (v H) / T} (v H)> T mp (v L) / T (v L),
_{T mp '(v H) /} T (v H)> T mp' (v L) / T (v L)
And in real time,
T _mp (v _H ) <T _mp (v _L ),
T _mp '(v _H ) <T _mp ' (v _L )
It is preferable that

This point will be described with reference to a schematic diagram shown in FIG. Here, in order to simplify the explanation, for example, v _L = 1.0, v _H = 2.0, T _mp (v _L ) = 0.3 T (v _L ), T _mp (v _H ) = 0. Assuming 5T (v _H ), T _mp (v _H ) <T _mp (v _L ) as shown in the real time side of FIG. 8A, but as shown in FIG. The duty normalized by the basic clock periods T (v _L ) and T (v _H ) is T _mp (v _L ) / T (v _L ) = 0.3, T _mp (v _H ) / T (v _H ) = 0.5, T _mp (v _H ) / T (v _H )> T _mp (v _L ) / T (v _L ). In other words, the duty T _mp (v) / T (v) and T _mp '(v) / T (v) normalized by the basic clock period T (v) are reversed according to the magnitude of the scanning speed. Means good.

The irradiation times T _mp and T _mp ′ are preferably expressed by a function proportional to α = v / v ₀ that is a function of the scanning speed v,
T _mp (α) / T (α) = a × α + b
More preferably, However, v ₀ is the recordable minimum scanning speed of the optical information recording medium, alpha is one or more real. The range of α represents the scanning speed at which the optical information recording medium can be recorded. For example, in consideration of using a CAV (Constant Angular Velocity) method of a disk type recording medium having a diameter of 120 mm, 1-2 .4 is preferable, and 1-4 is more preferable. That is, L ₀ = 278 nm, scanning speed v = 9.6 m / s to 38.4 m / s = 8x to 32x (v ₀ = 9.6 m / s = 8x, α = particularly assumed in the present embodiment) In the case of CD-RW which is 1-4), as shown in FIG.
0.14 ≦ a ≦ 0.29
0.2 ≦ b ≦ 0.4
It is preferable that Incidentally, in FIG. 9, 1x to 4x CD-RW (v ₀ = 1.2 m / s, α = 1 to 4), 4x to 10x HS CD-RW (v ₀ = 4.8 m / s, α). = 1 to 2.5), the duty T _mp / T characteristic is also shown. Further, in DVD + RW, v ₀ = 3.49 m / s and α = 1 to 2.4.

The constants a and b can be set in accordance with the characteristics of the optical information recording medium.
0.1 ≦ b ≦ 0.4
Such a range is preferable. By setting to such a range, it is possible to cope with a recording strategy assumed when α is 1 to 4.

Further, the irradiation time T _mp ′ when n = 3 also varies depending on α, but based on the above function,
T _mp ′ (α) = (T _mp (α) / T _mp (1)) × T _mp ′ (1)
The value calculated in (1) can be used.

  As described above, by relatively shortening the pulse irradiation time Tmp with respect to the basic clock cycle T, it is possible to realize a recording method in which the power Pw does not change greatly even when α varies. Therefore, it is suitably applied to CAV recording or Z-CLV (Zone CLV: a method for performing pseudo CAV recording by performing CLV recording for each radius range, and corresponding to CAV when the limit of 0 in the radius range is taken). can do.

[Preformatting to optical information recording media]
As described above, a recording method using a complicated recording strategy can be defined with limited parameters. By pre-formatting the information of these parameters on each optical information recording medium, the information recording apparatus reads these parameter information from the symmetrical optical information recording medium, thereby setting highly accurate recording conditions. Is possible.

  This embodiment is characterized by pre-formatting these parameters in an optical information recording medium.

  Although any method can be used for the preformat, there are a prepit method, a wobble encoding method, and a format method. The pre-pit method is a method for pre-formatting information on recording conditions using ROM pits in an arbitrary area on an optical information recording medium. Since ROM pits are formed when the substrate is formed, it is excellent in mass productivity and uses ROM pits, which is advantageous in terms of reproduction reliability and information amount. However, the technology for forming ROM pits (ie, hybrid technology) has many problems, and preformat technology using RW prepits is considered difficult.

  In the format method, information is recorded using an optical information recording apparatus using a method similar to normal recording. However, this method is difficult in terms of mass productivity because it is necessary to format each medium after manufacturing the optical information recording medium. Furthermore, since the preformat information can be rewritten, it is not suitable as a method for recording information unique to the medium.

  The wobble encoding method is a method actually used in CD-RW and DVD + RW. This method uses a technique for encoding address information of an optical information recording medium into wobbling of a groove (guide groove on the medium). As an encoding method, frequency modulation may be used like ATIP of CD-RW, or phase modulation may be used like DVD + RW. Since the wobble encoding method is created on the substrate together with the address information when forming the substrate of the optical information recording medium, it is excellent in productivity and at the same time, it is not necessary to form special ROM pits like the pre-pit method. There is an advantage that molding can be easily performed.

  Now, an example of pre-formatting of parameters relating to the recording strategy as described above will be described using an example of CD-RW. 10 and 11 show a format example of each area of the optical information recording medium 1 of the CD-RW standard. In the disk-shaped optical information recording medium 1, in the groove forming area where the groove is formed, the inner peripheral unused area 2, the test recording area 3, and the lead-in area 4 are arranged from the radially inner periphery toward the outer periphery. The information recording area 5, the lead-out area 6, and the outer peripheral unused area 7 are allocated in this order.

  In the case of such an optical information recording medium 1 such as a CD-RW, the media information to be preformatted is ATIP Extra Information. ATIP Extra Information is a technique using ATIP indicating address information. ATIP is address information preformatted on a CD-RW disc. Since the CD-based disc is based on the music information medium, the address is expressed as time information, so it is expressed as M: S: F. Here, M is minutes, and can be in the range of 00 to 99 in the standard, S is equivalent to seconds, takes a range of 00 to 59, F is a frame, and a range of 00 to 74 Take. 1 minute = 60 seconds, which corresponds to 1 second = 75 frames. Since 8 bits of information are given to M, S, and F, the information amount of one ATIP frame is 24 bits. For each of M, S, and F, values from 0 to 255 can be given, but only the above-described range is actually used. For this reason, if bits that are not used are used, information other than addresses can be added. This method was used by ATIP Extra Information.

  The data format of one ATIP frame is composed of 42-bit information as shown in FIG. The first 4 bits are called a synchronization part and indicate the start of a frame. In order for the information recording apparatus to recognize the synchronization unit as the start of a frame when reproducing ATIP, it is configured with a special pattern called a synchronization pattern. The 24 bits up to the 5th to 28th bits following the synchronization part are the address information part. The 24 bits are further divided into three parts of 8 bits each, the M1 to M8 parts represent the address information M (ie, minutes), and the S1 to S8 parts represent the address information S (ie, seconds). , F1 to F8 represent F (that is, a frame) of the address information. The 14 bits from the 29th to the 42nd bit following the address information part are a part called “CIRC Reminder”. This corresponds to a code for error correction using CIRC (Cross Interleved Reed-Solomon Code).

  In the standard of CD-RW, the contents of the address information part are classified into the following seven types by the combination of M1, S1, and F1 in the address information.

(M1, S1, F1) = (0,0,0) or (1,0,0): Normal address
(M1, S1, F1) = (1,0,1): Special Information 1
(M1, S1, F1) = (1,1,0): Special Information 2
(M1, S1, F1) = (1,1,1): Special Information 3
(M1, S1, F1) = (0,0,1): Additional Information 1
(M1, S1, F1) = (0,1,0): Additional Information 2
(M1, S1, F1) = (0,1,1): Additional Information 3
Among these pieces of information, information other than the normal address is used as ATIP Extra Information. Information specific to the disc is given to these ATIP Extra Information. Examples of the information include disc type information, recording conditions (parameters for setting recording power and optimum recording power, parameters for defining strategies). and so on.

  ATIP Extra Information is placed in the lead-in area 4 of the optical information recording medium 1, and after 9 frames of normal addresses, one frame of ATIP Extra Information is added. That is, in order to reproduce six types of ATIP Extra Information, it is necessary to reproduce at least 60 frames of the lead-in area 4.

Here, T _d1 / T, T _d2 / T, T _d2 ′ / T, T _mp / T, normalized by the basic clock period T, are used as parameters that define the recording strategy in the information recording method of this embodiment. It is _{assumed that} six types T _mp ′ / T and δ / T are adopted and preformatted on the optical information recording medium 1. Information shall be included in Additional Information 1 of ATIP Extra Information.

  In Additional Information 1, M1, S1, and F1 are fixed to 0, 0, and 1, respectively, so that the address information portion is as shown in FIG. Therefore, each bit is assigned to the following parameter expression.

(M2, M3, M4): T _d1 / T
(M5, M6, M7): T _d2 / T
(M8, S2, S3): T _d2 '/ T
(S4, S5, S6): _Tmp / T
(S7, S8, F2): T _mp '/ T
(F3, F4, F5): δ / T
In this example, the information amount for 3 bits is given to each parameter. That is, eight levels of information can be given for each parameter. The relationship between each bit and the parameter value (real number) is performed by using a conversion table. Examples of conversion tables 11a to 11f for each bit and each parameter are shown in FIGS.

  Now, it is assumed that an optical information recording medium 1 can be recorded with the best characteristics with the following parameter values.

T _d1 /T=0.50
T _d2 /T=0.00
T _d2 '/T=0.25
T _mp /T=1.00
T _mp '/T=1.60
δ / T = 0.14
When the value of each bit is obtained based on the conversion tables 11a to 11f shown in FIGS.
(M2, M3, M4) = (0, 1, 1)
(M5, M6, M7) = (1, 0, 0)
(M8, S2, S3) = (1, 0, 1)
(S4, S5, S6) = (1, 0, 0)
(S7, S8, F2) = (1, 0, 1)
(F3, F4, F5) = (0, 1, 0)
It becomes. Accordingly, the bit information of each parameter preformatted in Additional Information 1 is as shown in FIG. 14 (here, X is arbitrary because it is not defined).

  If the physical characteristics are different and the optimum values of the recording strategy parameters are different, the bit information converted using the conversion tables 11a to 11f may be preformatted into Additional Information 1 in the same manner.

  By the way, the wobble encoding method tends to reduce the absolute amount of information as compared with other methods. Normally, the wobble frequency is a frequency band in which mutual interference does not occur with respect to the frequency of recorded information. The frequency is 1/30 or less, more preferably 1/100 or less. Furthermore, if frequency modulation is used as the modulation method, the information density is further reduced, and if the redundancy of address information is used as in the ATIP EXTRA INFORMAITION of CD-RW, the information density is further reduced.

  However, when the amount of information is insufficient, a new area may be provided. In the case of a CD-RW, ATIP EXTRA INFORMATION is encoded in the lead-in area 4. However, if only this area is insufficient, it is encoded in the unused area 2 or 7 on the inner or outer peripheral part of the disc. good. As an example of the unused areas 2 and 7, an inner peripheral part and an outer peripheral part of the lead-out area 6 can be cited rather than PCA (Power Calibration Area = test recording area).

  As for the parameter to be encoded, a value obtained by converting a real number into a binary number may be encoded as in the above-described example, or information converted using a conversion table may be encoded. However, regardless of which method is used, the information recording apparatus needs a means capable of decoding the encoded information and correctly setting the recording strategy.

[Recording strategy generation method]
The information recording apparatus corresponding to the optical information recording medium 1 called CD-RW reproduces the above ATIP Extra Information during a recording operation to the optical information recording medium 1 (including when the medium is mounted). In the recording apparatus corresponding to the optical information recording medium 1 described above, it is necessary to be able to reproduce the Additional Information 1 and further to have a conversion table for converting the bit into a real number. The information recording apparatus reproduces Additional Information 1 and obtains the value of each bit from the optical information recording medium 1. The real number of the parameter can be acquired using the conversion tables 11a to 11f for the bit information. The information recording apparatus can set an optimum recording strategy based on the real values of these parameters. In the optical information recording medium 1 having the different optimum recording strategy, that is, the optical information recording medium 1 having different parameter values, the optimum parameter for the Additional Information 1 is preformatted. It is possible to set an optimal recording strategy.

  A processing procedure of such a recording strategy generation method will be described with reference to a schematic flowchart shown in FIG. This process is executed by a system controller described later in the information recording apparatus, for example.

First, prior to the recording operation, preformat information is reproduced from the optical information recording medium 1 that is mounted and targeted (step S1). That is, an address at which the parameters T _d1 / T, T _d2 / T, T _d2 ′ / T, T _mp / T, T _mp ′ / T, and δ / T relating to the recording strategy are accessed and the preformat information is obtained. Play. The reproduced preformat information (bit information of parameters _Td1 / T, _Td2 / T, _Td2 '/ T, _Tmp / T, _Tmp ' / T, δ / T) is decoded (S2). That is, each parameter information is converted from bit information to real number information using the conversion tables 11a to 11f. Then, a recording strategy is generated and set so as to obtain an optimum multi-pulse pattern using real number information of the converted parameters T _d1 , T _d2 , T _d2 ′, T _mp , T _mp ′, and δ (S3). . Thereafter, an optimum recording power setting process is performed as necessary (S4). In other words, this is a trial writing for verifying the validity of the set recording strategy and setting the optimum recording power. As an example of the trial writing, an OPC (Optimum) adopted in CD-R / RW and DVD + RW / R is used. (Power Control) may be used. In the recording operation, recording is performed based on a predetermined recording strategy using the recording power determined by such an operation (S5).

[Information recording device]
Next, a configuration example of an information recording apparatus for realizing the information recording method based on the recording strategy described above will be described with reference to FIG.

  First, a rotation control mechanism 22 including a spindle motor 21 that rotates the optical information recording medium 1 is provided for the optical information recording medium 1 that is a CD-RW, and a laser is applied to the optical information recording medium 1. An optical head 24 having an objective lens for condensing and irradiating light and a laser light source such as a semiconductor laser LD23 is provided so as to be able to seek in the radial direction of the disk. An actuator control mechanism 25 is connected to the objective lens driving device and output system of the optical head 24. A wobble detection unit 27 including a programmable BPF 26 is connected to the actuator control mechanism 25. The wobble detection unit 27 is connected to an address demodulation circuit 28 that demodulates an address from the detected wobble signal. A recording clock generator 30 including a PLL synthesizer circuit 29 is connected to the address demodulating circuit 28. A drive controller 31 is connected to the PLL synthesizer circuit 29 as speed control means.

  The rotation controller 22, the actuator controller 25, the wobble detector 27, and the address demodulator 28 are also connected to the drive controller 31 connected to the system controller 32.

  The system controller 17 has a so-called microcomputer configuration including a CPU, and includes a ROM 33 including the conversion tables 11a to 11f described above. Further, an EFM encoder 34, a mark length counter 35, and a pulse number control unit 36 are connected to the system controller 17. The EFM encoder 34, the mark length counter 35, the pulse number control unit 36, and the system controller 17 are connected to a recording pulse train control unit 37 serving as a light emission waveform control means. The recording pulse train control unit 37 includes a multi-pulse generation unit 38 that generates a multi-pulse (on pulse, off-pulse) defined by a recording strategy, an edge selector 39, and a pulse edge generation unit 40.

  On the output side of the recording pulse train controller 37, light source driving means for driving the semiconductor laser LD23 in the optical head 24 by switching the respective driving current sources 41 of the recording power Pw, the erasing power Pe, and the bias power Pb. The LD driver unit 42 is connected.

  In such a configuration, in order to record on the optical information recording medium 1, the rotation control mechanism controls the rotational speed of the spindle motor 21 under the control of the drive controller 31 so that the recording linear velocity corresponds to the target recording velocity. 22, the address demodulation is performed from the wobble signal separated and detected by the programmable BPF 26 from the push-pull signal obtained from the optical head 24, and the recording channel clock is generated by the PLL synthesizer circuit 29. Next, in order to generate a recording pulse train by the semiconductor laser LD 23, a recording channel clock and EFM data as recording information are input to the recording pulse train controller 37, and the multi-pulse generator 38 in the recording pulse train controller 37 performs FIG. A multi-pulse is generated in accordance with the recording strategy as shown in FIG. 6 and the drive current source 41 set so as to have the above-described irradiation powers Pw, Pe, and Pb is switched by the LD driver unit 42, whereby a recording pulse train LD emission waveform according to the above can be obtained.

  By the way, in the present embodiment, a multi-stage pulse edge generation unit 40 having a resolution of 1/20 of the recording channel clock period is arranged in the recording pulse train control unit 37 and is input to the edge selector (multiplexer) 39. Thereafter, a rising control signal of the first pulse or the like is generated by the edge pulse selected by the system controller 32 based on the parameter Td1. The multi-stage delay circuit for the pulse edge generator 40 can be configured by a high-resolution gate delay element, ring oscillator, and PLL circuit.

Based on the rising control signal of the first pulse generated in this way, the parameter Tmp, T _mp ', a multi-pulse train synchronized with the reference clock period T based on the δ or period nT / m, etc. are generated. Similarly, with respect to the irradiation time T _off (n, m) of the final off pulse, the rising control signal of the final off pulse is generated by the edge pulse selected by the system controller 32 based on the parameter T _d2 or T _d2 ′.

  Further, in the recording pulse train control unit 37 configured as in the present embodiment, a mark length counter 35 for counting the mark length of the EFM signal obtained from the EFM encoder 34 is disposed, and the mark count value is 2T. A multi-pulse is generated via the pulse number control unit 36 so that one set of pulses (an on-pulse with power Pw and an off-pulse with power Pb) is generated each time the number increases. In this operation, after selecting the trailing edge of the first pulse by the edge selector 39, the leading edge of the subsequent multi-pulse is selected by the edge pulse generated from the next recording channel clock period, and the next recording channel clock is selected. This is possible by selecting the trailing edge of the multi-pulse with the pulse edge generated from the period.

  As another configuration of the multi-pulse generation unit, a recording frequency-divided clock obtained by dividing the recording channel clock by two is generated, an edge pulse is generated using a multi-stage delay circuit, and the front and rear edges are selected by the edge selector. Thus, every time the recording channel clock increases by 2T, one set of pulses (an on-pulse with power Pw and an off-pulse with power Pb) can be generated. In the case of this configuration, the substantial operating frequency of the multi-pulse generator is halved, and further high-speed recording operation is possible.

[Modification]
In the above description, an example of application to a phase change type optical information recording medium has been described. However, the present invention can also be applied to a so-called dye-based optical information recording medium such as a CD-R or DVD-R that can only be additionally written. is there. In this case, regarding the power to be irradiated, it is assumed that Pe≈Pb, and as shown in FIG. 23, the irradiation power Pb is between the pulse P _on (n, i) and the pulse P _on (n, i + 1) by the irradiation power Pw. It becomes a binary pattern irradiated with.

  A lower dielectric layer, a recording layer, an upper dielectric layer, and a reflective layer were sequentially formed on a polycarbonate CD-RW substrate by sputtering. As the lower dielectric layer material and the upper dielectric layer material, a dielectric material obtained by mixing 20 mol% of SiO2 with ZnS was used, and as the recording layer, a material obtained by adding a trace amount of Ge to an AgInSbTe alloy was used. Ag was used as the reflective layer material. The thickness of the lower dielectric layer was 70 nm, the recording layer thickness was 15 nm, the upper dielectric layer was 20 nm, and the reflective layer was 140 nm. Further, a protective layer made of resin was formed thereon by a spin coating method and cured by irradiating with ultraviolet rays. As the protective layer material, a UV effect resin which is a commercially available protective layer material for CD was used. The film thickness of the protective layer was about 10 μm.

  After film formation, the recording layer is in a rapidly cooled state and is in an amorphous state. Therefore, in order to crystallize the entire disk surface, initialization was performed using a CD-RW initialization apparatus. Initialization was performed by irradiating and scanning the entire surface with a high-power laser. The initialization laser had a wavelength of 830 nm, and the beam diameter was 1 μm in the scanning direction and 80 μm in the vertical direction. The irradiation intensity was 800 mW (power consumption) and the scanning speed was 2.5 m / s. The completed disc satisfied each standard of CD-RW discs in an unrecorded state.

  A recording experiment equivalent to 24 times the speed of a CD was performed on such a disk. DDU1000 manufactured by Pulstec Industrial was used as the information recording / reproducing device, and AWG610 manufactured by Sony Tektronix was used as the recording strategy generator. The prepared strategy pattern is as shown in FIG. 7, and each parameter is as follows.

T = 9.6 ns
T _mp /T=1.125
T _mp '/T=1.563
δ / T = 0.125
T _d1 /T=0.50
T _d2 /T=0.05
T _d2 '/T=0.10
Using such a parameter setting recording strategy, recording corresponding to 24 × speed was performed. The recording conditions are as follows.

Pw = 32mW
Pe = 11mW
v = 28.8 m / s
DOW times = 1-1000
(DOW: Abbreviation of Direct Over Write. Rewriting without erasing operation, which can be performed 1000 times or more in the CD-RW standard)
When 3T mark jitter and 3T space jitter were measured at the standard speed of CD (v = 1.2 m / s) after recording, the results shown in Table 1 were obtained.

表１に示す結果によれば、ＤＯＷ回数１０００回まで、ＣＤ−ＲＷ標準規格であるジッタ＜３５ｎｓ以下なる条件を満足していることを確認できたものである
。

According to the results shown in Table 1, it was confirmed that the condition of jitter <35 ns or less, which is a CD-RW standard, was satisfied up to 1000 DOW times.

  Recording on a CD-RW disc created in Example 1 was performed at a speed corresponding to 8 times the speed of a CD. As the recording strategy, only Tmp / T and Tmp ′ / T in the strategy of Example 1 were changed.

T _mp /T=0.500 (4/9 of Example 1)
T _mp '/T=0.695 (4/9 of Example 1)
T = 28.9 ns
The same values as in Example 1 were used for δ / T, T _d1 / T, T _d2 / T, and T _d2 ′ / T.

  The recording conditions were as follows.

Pw = 30mW
Pe = 9mW
v = 9.6 m / s
DOW count = 1 to 1000 times After recording, 3T mark jitter and 3T space jitter were measured at a standard speed, and the results shown in Table 2 were obtained.

表２に示す結果によれば、照射時間Ｔ_ｍｐ，Ｔ_ｍｐ’を４／９倍にすることだけで、８倍速相当でも記録可能であることを確認できたものである。また、ＤＯＷ回数１０００回でも、ジッタ＜３５ｎｓであり、良好な特性を示していることを確認できたものである。

According to the results shown in Table 2, it was confirmed that the recording was possible even at the 8 × speed by simply increasing the irradiation times T _mp and T _mp ′ to 4/9 times. In addition, it was confirmed that even when the number of DOWs was 1000, jitter was less than 35 ns and good characteristics were shown.

  Considering the first and second embodiments, the information recording apparatus can set an optimal recording strategy by pre-formatting the following parameter information in the optical information recording medium 1.

δ / T = 0.125
T _d1 /T=0.50
T _d2 /T=0.05
T _d2 '/T=0.10
a = 3.125
b = 0.188
α = 3

It is a wave form diagram which shows the outline of the recording strategy of one embodiment of this invention. It is a wave form diagram which shows the outline of the recording strategy for extracting 3T, 4T, 5T, 10T, and 11T and considering it. T _on (n, m) is a characteristic diagram showing the relationship between the mark Deviation D (n). It is a characteristic diagram showing the relationship between the pulse T _on other than the last pulse _(n, i) and Mark Deviation D (n). It is a characteristic view which shows a mode that a pulse period reduces when n is an odd number. It is a characteristic view which shows a mode that the irradiation time of the last off pulse reduces when n is an odd number. It is a wave form diagram which shows the outline of the recording strategy of this Embodiment prescribed | regulated by few parameters. It is explanatory drawing which shows a mode that the duty of irradiation time changes with the change of a scanning speed. It is a characteristic view which shows the function which changes the duty of irradiation time with the change of scanning speed. It is a top view which shows area allocation of an optical information recording medium. FIG. It is explanatory drawing which shows the data format of 1 ATIP frame. It is explanatory drawing which shows the pre format allocation area | region of the parameter of an address information part. It is explanatory drawing which shows the example of preformatted bit information. It is explanatory drawing which shows the conversion table for parameter Td1. It is explanatory drawing which shows the conversion table for parameter Td2. It is explanatory drawing which shows the conversion table for parameter Td2 '. It is explanatory drawing which shows the conversion table for parameter Tmp. It is explanatory drawing which shows the conversion table for parameter Tmp '. It is explanatory drawing which shows the conversion table for parameters (delta). It is a flowchart which shows the outline of a recording strategy production | generation process. It is a schematic block diagram which shows the structural example of an information recording device. It is a wave form diagram which shows the outline of the recording strategy of a modification. It is a wave form diagram which shows the outline of the recording strategy of a prior art example. It is explanatory drawing which shows the actual light emission waveform with respect to an ideal irradiation waveform.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical information recording medium 22 Rotation drive mechanism 23 Laser light source 31 Speed control means 37 Light emission waveform control means 42 Light source drive means

Claims (3)

In an optical information recording medium on which information is recorded by a mark length recording method corresponding to nT in which the time length of a recording mark is n times the basic clock period T (n is a natural number),
n ₌ n 1 ₌ 2m (m is a natural number of 2 or more) corresponding to the time length _{n 2} · T when the recording mark and _n = _n 2 = 2m + 1 corresponding to the time length _{n 1} · T in the case of When the recording mark to be recorded is formed by m multi-pulses with irradiation power Pw, the irradiation time of the i-th pulse (i is a natural number of 1 to (m−1)) is represented by T _on (n, i). When n ≧ 4, T _on (n, i) = constant T _mp and T _on (n ₁ , i) = T _on (n ₂ , i) is included, and n = n ₂ In addition, there are recording strategies including those in which the irradiation period of the irradiation power Pw is larger than 2T, and the time width between pulses of the irradiation power Pw is different when n = n ₁ and n = n _2. When used, the parameters for setting the irradiation power Pw are preset. An optical information recording medium characterized by being matted.   The optical information recording medium according to claim 1, wherein the preformatted parameter is a parameter for setting a minimum scanning speed when the recording strategy is used.   The optical information recording medium according to claim 1, wherein the preformatted parameter is a parameter for setting a time width of the irradiation power Pw.

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