JP2000123369A - Method and device for recording information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a proper recording mark by correcting the length of a long mark before correcting a table. SOLUTION: In this information recording method, in the case of recording information on a recording medium by converting a energy beam into multiple pulses, edge positions of a head pulse and a last pulse are controlled by referring to a table from back and forth mark lengths and space lengths and the length of the necessary long mark is corrected before updating the table. The mark length is measured from a slicer signal or a measurement result of an edge interval by using repeated patterns of the long mark and the long space and the positions of the head and last pulses are corrected before updating the table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording method and an information recording apparatus using an information recording medium on which information can be recorded by irradiating an energy beam, and more particularly to an information recording medium having an excellent effect on a phase change optical disk. The present invention relates to a recording method and an information recording device using the information recording method.

[0002]

2. Description of the Related Art Known examples (patent publications or document names) "Japanese Patent Laid-Open No. Sho 62-175948, Japanese Patent Laid-Open No. Sho 62-259229, Japanese Patent Laid-Open No. Hei 3-185629, JIS Standard 120 mm DVD Rwritable Di
sk (DVD-RAM) JISX6243] A conventional method of recording / erasing data on / from a rewritable recording film is, for example, as described in Japanese Patent Application Laid-Open No. 62-175948. For a phase-change type optical disk capable of high-speed erasing in which crystallization can be performed in approximately the same time as the recording laser irradiation time disclosed in Japanese Patent Application Laid-Open No. 62-259229. When the recording film is used, the power of one energy beam is changed by changing at least two levels higher than the read power level, that is, at least between a high power level and an intermediate power level. This method has an advantage that so-called overwriting (rewriting by overwriting) in which new information is recorded while erasing existing information is possible. Further, as disclosed in JP-A-62-259229 and JP-A-3-185629, three levels of a high power level, an intermediate power level, and a lower power level than the intermediate power level are provided. By changing the energy beam between the recording marks, it is possible to suppress the phenomenon that the recording mark becomes teardrop-shaped (the rear part of the recording mark becomes wider than the front part).

[0003] Also, using a recent phase change material,
DV with a disk with a diameter of 2.6 GB on one side
D-RAM has been put to practical use. The recording control method adopted here is described on page 86 of the standard specification JIS X6243. Here, the control based on the above three levels is described.

[0004]

At present, a rewritable digital video disk (DVD) using a phase-change recording film is known.
−RAM) is being researched for higher density. DVD-R
In an optical disk device that performs mark edge recording on a phase change recording film, such as AM, in order to prevent mark shape distortion and unerased portions, the outer edge of an area where the recording film is melted to form a recording mark on the recording film is formed. In any case, it is necessary that the ultimate temperature and the cooling rate during recording be almost the same. However, various recording waveforms known so far cannot sufficiently satisfy the above condition, and there is a limit to a achievable recording density. In addition, the recording characteristics of an information recording medium usually differ depending on the medium manufacturer, the manufacturing period, and the lot, and the higher the recording density, the more difficult it is to secure compatibility in recording. Tended to be.

[0005] In particular, 4.7, which is higher density than 2.6 GB
In a DVD-RAM having a recording capacity of GB, recording with the same spot diameter as 2.6 GB facilitates compatibility with 2.6 GB. However, when the same spot is used and the linear density is reduced, the interval between the positions at which two adjacent recording pulses are irradiated on the recording medium is smaller than the diameter of the laser spot on the recording medium. In other words, since the light distribution overlaps when the light distribution is 2.6 GB, it is necessary to prevent the recording mark shape distortion caused by the overlap. Further, even if the same recording medium is used, if the degree of distortion of the condensed spot is slightly different, the recording state is different for each recording device, and the recording mark shape distortion is different for each recording device. . This leads to the fact that the same recording cannot be performed over all the recording devices under the same recording condition, and a situation may occur where it is difficult to maintain the compatibility of the recording.

Further, in a recording method for recording information on a recording medium by converting an energy beam into multi-pulses and controlling the edge positions of a first pulse and a last pulse with reference to a table, the length of a long mark is updated when the table is updated. If the table is corrected without correcting the error, there is a problem that a proper recording mark cannot be formed.

Accordingly, an object of the present invention is to record information using the same spot as that of the above-described conventional technique, enabling accurate recording to further increase the density while maintaining compatibility with the conventional technique, and achieving recording compatibility. It is to provide a method and an information recording device. In particular, it is an object of the present invention to provide a recording method for accurately determining the timing of a multi-pulse when an energy beam for forming a recording mark is multi-pulsed, and an information recording apparatus having the recording method.

[0008]

In order to solve the above-mentioned problems, the following information recording method and information recording device may be used.

(1) A recording medium which can be set to a first state at a first power level of an energy beam and to a second state at a second power level higher than the first power level is used. Irradiating the energy beam onto the recording medium by relatively moving the energy beam and the recording medium, so that the first state and the second state are separated by a predetermined length and interval. A method of recording information on a recording medium by forming information on the recording medium, wherein a third power level lower than the second power level is provided, and the second state having a specific length is provided. When forming the area of the recording medium, the energy beam is multi-pulsed by mixing the period of the third power level with the period of the second power level to record the energy beam. A method of recording information characterized by irradiating the medium with the head pulse timing adjustment method or the final pulse timing adjustment method described below, having one or both of them, and the relative position between the energy beam and the recording medium. Forming a region in the second state having a length equal to or more than half the length of the energy beam in a typical moving direction on the recording medium to obtain a reproduction signal thereof; Having a measuring method for measuring the length of the region of the second state having a length of at least half of the length of the region of the second state having a length of at least half of the length of the energy beam. If the length is different from the predetermined length, use either the following first pulse timing adjustment method or the last pulse timing adjustment method, or one or both of them. Information recording method and adjusting the timing of the multi-pulse for forming the region of the second state. However, the head pulse timing adjustment method is the timing adjustment method 1 for adjusting the timing at which the energy beam reaches the second power level in the head pulse of the multi-pulse train,
Either timing adjustment method 2 for adjusting the timing at which the energy beam departs from the second power level in the leading pulse of the multi-pulse train, or one or both of them. The final pulse timing adjusting method is a timing adjusting method 3 for adjusting the timing at which the energy beam reaches the second power level in the final pulse of the multi-pulse train.
Alternatively, a timing adjustment method 4 for adjusting the timing at which the energy beam departs from the second power level in the last pulse of the multi-pulse train, or a timing adjustment method including one or both of them.

(2) An energy beam generator, and a power capable of setting a power level of an energy beam generated by the energy beam generator to a first power level and a second power level higher than the first power level. An adjusting mechanism, a holding mechanism capable of holding a recording medium capable of being brought into a first state at the first power level and a second state at the second power level, and the energy beam; A moving mechanism capable of relatively moving the recording medium, a positioning mechanism capable of irradiating the energy beam to a predetermined location of the recording medium, and information to be recorded at a power level of the energy beam. A signal processing circuit for changing the power level, wherein the power adjustment mechanism has a third power level lower than the second power level. When forming the area in the second state on the recording medium, when forming the area in the second state to a specific length, the area in the second power level In the information recording apparatus, the power adjusting mechanism has a function of multi-pulsing the energy beam by mixing the periods of the third power level. The second state having pulse timing adjusting means, one or both of them, and having a length equal to or more than half the length of the energy beam in the relative movement direction between the energy beam and the recording medium; Forming an area on the recording medium to obtain a reproduced signal, and measuring the length of the area in the second state having a length of at least half the length of the energy beam. The first pulse timing adjusting means or the last pulse timing when the length of the region in the second state having a length equal to or more than half the length of the energy beam is different from a predetermined length. An information recording apparatus for adjusting a timing of a multi-pulse when forming an area in a second state by using an adjusting means, one or both of them. However, the head pulse timing adjustment means is
Either the timing adjusting means 1 for adjusting the timing at which the energy beam reaches the second power level in the first pulse of the multi-pulse train, or the timing for deviating the energy beam from the second power level in the first pulse of the multi-pulse train Timing adjusting means 2 or one or both of them. The final pulse timing adjusting means may be timing adjusting means 3 for adjusting the timing at which the energy beam reaches the second power level in the last pulse of the multi-pulse train, or the energy beam may be adjusted to the second pulse in the last pulse of the multi-pulse train. The timing adjusting means 4 adjusts the timing of departure from the power level, or one or both of them.

(3) In a recording method for recording information on a recording medium by converting an energy beam into multi-pulses and controlling at least one edge position of a first pulse and a last pulse with reference to a table, a long mark and a long space are recorded. Information characterized by measuring a mark length from a slicer signal or an edge interval measurement result using a repetitive pattern, correcting the timing of at least one of the first pulse and the last pulse using the result, and updating the table. Recording method. Here, the above-described head pulse timing adjustment method or the last pulse timing adjustment method is used for correcting the first pulse and the last pulse.

(4) A recording apparatus that includes a table, multi-pulses an energy beam, and controls at least one edge position of a first pulse and a last pulse with reference to the table to record information on a recording medium. Using a repetitive pattern of marks and long spaces, measure the mark length from the slicer signal or the edge interval measurement result, use this result to correct the timing of at least one of the first pulse and the last pulse, and update the table An information recording device characterized by the above-mentioned. Here, the above-described head pulse timing adjustment method or the last pulse timing adjustment method is used for correcting the first pulse and the last pulse.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the following examples.

First, an example of a temporal change in the power level of an energy beam applied to a recording medium when information is recorded on the recording medium will be described with reference to FIG. Here, how to change the power level over time when recording information is generally referred to as a write strategy or a recording strategy. Here, as a specific example, a DVD-RAM
Will be described as an example. In the case of a DVD-RAM, when the time width of a reference clock in recording and reproduction is T, the length of the shortest mark to the shortest space is 3
T (time three times longer than the time T), and usually the length of the longest mark to the longest space is 11T. There is a 14T mark or space as a special pattern.

When an NRZI signal, which is information to be recorded in a time series on a recording medium, is given, the NRZI signal is converted into a time series change in the power level of the energy beam by an appropriate signal processing circuit. Such a chronological change in the power level is shown as an optical pulse waveform in FIG. Power levels are Peak Power, Bias Power 1, Bi
As Power 2 and Bias Power 3 are set to four levels. In Bias Power 1, the recording medium is in the first state, Peak
With Power, the recording medium can be moved to the second state. Bias Power 3 is at a level equal to or lower than Bias Power 1. No. on the recording medium
When forming the region of the second state, if the length of the region of the second state is 4T or more (that is, if the length of the NRZI signal is 4T or more), during the irradiation period of Peak Power, To
The energy beam is multi-pulsed by mixing Bias Power 3 power level periods. In the multi-pulsed energy beam, the first light pulse is called the first pulse, and the last light pulse is called the last pulse. An optical pulse that repeats Peak Power and Bias Power 3 is repeated between the first pulse and the last pulse in accordance with the length of the NRZI signal, and the number of repetitions is n times the length of the NRZI signal ( If n> 3), then (n-4) times. The entire repetition pulse sandwiched between the first pulse and the last pulse is called a comb pulse. That is, when forming the second state area corresponding to the NRZI signal having a length of 5T or more, the recording pulse includes a head pulse, a comb pulse, and a final pulse. In the case of forming an area in the second state corresponding to an NRZI signal having a length of 4T, the recording pulse includes the first pulse and the last pulse. Further, when forming an area in the second state corresponding to an NRZI signal having a length of 3T, the recording pulse is a single optical pulse.

Bias Power 2 having a power level equal to or lower than Bias Power 1 is used. At 4T or more, the power level is held at Bias Power 2 for a predetermined time after the last pulse, and after 3T, after a single optical pulse.

Bias Power 2 and Bias Power 1 or
Bias Power 3 may have the same power level. Also, Bias Power 1 and Bias Power 2
And Bias Power 3 can all be at exactly the same power level. Peak Power, Bias Power 1, Bias P
The reference value of ower 2 and Bias Power 3 is as media information,
It may be recorded in an appropriate place on the recording medium in advance. The portion on the recording medium on which the medium information relating to the recording strategy is recorded is called an information track of the control data zone. The power level reference value is read from the information track in the control data zone of the recording medium, and each power level at the time of writing is determined with reference to this.

First, let us consider the case where a second state area corresponding to an NRZI signal of 4T or more is formed on a recording medium, and consider the definition of a recording waveform. The rise of the leading pulse of the write pulse train is defined at the time that has elapsed by T _SFP from the rise of the NRZI signal, and the fall of the leading pulse of the write pulse train is defined by the time that has elapsed by _TEFP from the rise of the NRZI signal. The length of the leading pulse is T _FP, this value is equal to the value obtained by subtracting the T _SFP from T _EFP. The rise of the last pulse of the write pulse train is based on the time preceding the fall time of the NRZI signal by the time 2T, and the last pulse rises at a time after a lapse of time T _SLP from this reference time. The fall of the last pulse of the write pulse train is based on a time preceding the fall time of the NRZI signal by a time 2T, and the last pulse rises at a time after a lapse of _TELP from this reference time. The length of the last pulse is T _LP, which is equal to T _{ELP minus} T _SLP .

There may be a comb pulse between the first pulse and the last pulse. The rising of each pulse of the comb-shaped pulse train coincides with the reference clock position, and each pulse falls at a time after a time T _{MP has} elapsed from the rising time of each pulse.

Next, consider a case where a second state area corresponding to a 3T NRZI signal is formed on a recording medium. N
The rising edge of the optical pulse exists at a time that has elapsed by T _SFP from the rising edge of the RZI signal. Further, the falling of the optical pulse is at time 2 from the falling time of the NRZI signal.
T based on the time preceding T by time T
_At the time when _{ELP has} elapsed, there is a falling edge of the light pulse.

After the last pulse after 4T or the recording pulse of 3T, the power level is changed to Bias Po.
There is partial a wer 2, this length is a T _LC.

A time defining a recording pulse,
T _SFP , _TEFP , T _FP , T _SLP , _TELP , T _LP , T _LC , T _MP
Reads the reference value from the information track in the control data zone of the recording medium and determines the value with reference to the reference value.

A time defining a recording pulse,
T _SFP , _TEFP , T _FP , T _SLP , _TELP , T _LP , T _LC , T _MP
Does not always take a constant value, and may need to be changed according to a combination of NRZI signals. In particular, taking the case of a 4.7 GB DVD-RAM on one side as an example, the length of the shortest mark 3T is about 0.42 μm, which is shorter than the writing spot radius of 0.45 μm. When such high-density recording is performed,
In some cases, thermal interference between adjacent marks increases, making it difficult to always perform stable recording. Therefore, it is conceivable to change the recording waveform adaptively according to the combination before and after the NRZI signal. There are the following two methods for correcting the shift of the leading edge.

[0024] 1) to fix the T _EFP, to change the T _SFP. In this case, T _FP is changed with the change of T _SFP.

2) T _FP is fixed and T _SFP is changed. At this time, _TEFP changes with the change of _TSFP .

There are the following two methods for correcting the shift of the trailing edge.

1) Fix T _SLP and change _TELP . At this time, T _LP changes with a change in _TELP .

2) Fix T _LP and change _TELP . At this time, T _SLP changes with a change in _TELP .

Which of the above methods is selected for controlling the leading edge and the trailing edge depends on the design method of the recording medium and the recording characteristics of the recording medium. Which should be selected for the shift control method of the front edge and the rear edge?
Since the manufacturer of the recording medium is best known, the manufacturer of the recording medium can recommend to the information recording apparatus which of the edge shift control methods should be selected. That is, the manufacturer of the recording medium writes the recommendation of the edge shift control method at a specific location on the recording medium, and the information recording apparatus reads this information to determine the edge shift control method. In such a case, the information recording apparatus can utilize the medium characteristics intended by the manufacturer of the recording medium without excess, and can record information most stably. Also, the manufacturer of the recording medium prepares a look-up table for edge shift control and records this on the recording medium. The information recording apparatus reads this look-up table, and performs edge shift control using the information as a reference, so that the information recording apparatus can use the medium characteristics intended by the manufacturer of the recording medium without leaving any excess. Information can be stably recorded. With the above-described contrivance, it is possible to provide a means that can achieve the highest recording compatibility even with high-density recording.

The look-up table for the leading edge indicates that the length of the mark currently being recorded is M
(N), and the length of the space preceding the mark is S
In the case of (n-1), values determined by a combination of M (n) and S (n-1) are arranged, and can take both positive and negative values.

The look-up table for the trailing edge indicates that the mark length currently being recorded is M
(N), and the space length following the mark is S (n +
In the case of 1), values determined by a combination of M (n) and S (n + 1) are arranged, and can take both positive and negative values.

As described above, by changing T _SFP and _TELP according to the combination before and after the NRZI signal, the mark edge position can always be controlled with high accuracy.

As described above, the information of the write strategy is previously written on the recording medium, and when the information is recorded by an actual recording apparatus, the information is read to realize an appropriate write strategy, so that the recording is always performed with high accuracy. Marks can be formed. However, the recording characteristics of the recording device are not always the same. That is, for each recording apparatus, the irradiation area when the recording medium is irradiated with the energy beam is different, or the shape of the energy beam is distorted. It is conceivable that the recording mark shape is slightly different every time. For this reason, the look-up table for edge shift control may need to be corrected or optimized for each printing apparatus based on the look-up table written on the printing medium. An example of a specific method used for performing such correction or optimization will be described with reference to FIG. Here, for the sake of explanation, it is assumed that the relative movement direction of the energy beam with respect to the recording medium is from the left side of the paper to the right side of the paper.
In a mark, a mark boundary in a direction opposite to the moving direction of the energy beam is called a front edge, and a mark boundary in the moving direction of the energy beam is called a rear edge.
Also, let v be the relative moving speed between the energy beam and the recording medium. Also, let T be a basic clock cycle in recording and reproduction. Further, a, i, m, j, and b are natural numbers.

FIG. 2A shows a recording pattern A, a reproduction signal corresponding thereto and a binarized signal. The position where the playback signal crosses the slice level from the upper side to the lower side of the paper is
The front edge of the reproduction signal is shown. The result of measuring the time interval from the leading edge of the mark having the length avT to the leading edge of the mark having the length mvT using the time interval measuring device using the reproduced signal is defined as a measurement time T1. If the measurement time T1 does not coincide with the time interval (a + i) T, it indicates that the leading edge of the mark having the length mvT does not exist at an appropriate position. In such a case, the value of the lookup table is adjusted to correct the position of the leading edge of the mark having the length mvT.

FIG. 2B) shows a recording pattern B, a reproduction signal corresponding thereto and a binarized signal. Using the reproduction signal, the length bvT from the rear edge of the mark of length mvT
The result of measuring the time interval up to the trailing edge of the mark with a time interval measuring device is defined as a measurement time T2. This measurement time T
2 does not match the time interval (j + b) T, the length mv
This indicates that the trailing edge of the T mark does not exist at an appropriate position. In such a case, the value of the look-up table is adjusted to correct the position of the trailing edge of the mark having the length mvT.

When performing such correction, a mark having a length avT or a mark having a length bvT is selected to have a length that is at least half the width of the energy beam in the moving direction of the energy beam. Choosing a length like this is the length avT
And the mark of length bvT serve as a reference when measuring the position of the mark edge of length mvT.
In the case of a mark having a length less than half of the width of the energy beam with respect to the moving direction of the energy beam, an extremely minute mark is formed with respect to the width of the energy beam. It is stable. Selecting a mark having such a short length and having a somewhat unstable mark formation as a reference mark for lookup table correction may degrade the accuracy of lookup table correction. Then, length av
The length of the mark of T or the length of the mark of bvT is selected to be longer than half the length of the energy beam in the moving direction of the energy beam. In some cases, even the shortest mark to be recorded may be at least half the length of the energy beam with respect to the moving direction of the energy beam. Even in such a case, the most stable recording mark is often a longer mark, and the lookup table is often corrected based on the longer mark.

However, the problem here is that if the precision of the mark length of the long reference mark is not accurate,
As a result, an excellent mark row cannot be formed.
This problem will be described with reference to FIG.

FIG. 3A shows a case where a mark having a length of cvT and a space having a length of cvT are to be alternately and continuously formed on a recording medium. It is assumed that the mark length of the length cvT is equal to or longer than half the width of the energy beam in the moving direction of the energy beam, and is a length that can be used as a reference mark in lookup table correction. Length c
This shows a situation in which when a mark of vT is formed on the recording film, the length of the mark of length cvT is shorter than the predetermined length by Δ. That is, the length of the actually formed mark is (c−Δ) vT, and the space length is (c + Δ)
vT. Consider slicing this reproduced signal, but the slicer uses a Duty Fe such as a DVD-RAM.
When the ed Back slicer is used, the slicer slices the reproduction signal at the slice position 1 in order to automatically adjust the slice level so that the length of the mark or space of the reproduction signal looks like cvT. In such a case, the slice level is separated from the middle level of the reproduction signal amplitude x by the value K. If the above-described look-up table correction is performed in such a situation, the edge positions of various marks are adjusted with respect to the slice position 1, so that all the marks are affected by a short length of the long mark. For example,
After the lookup table correction is completed, the mark of cvT and c
A pattern in which a vT space is repeated a finite number of times, a mark having a length (length dvT) less than half the width of the energy beam in the moving direction of the energy beam and a pattern in which the dvT space is repeated a finite number of times are recorded alternately. When the mark is formed and reproduced,
A reproduced signal as shown in b) is obtained. That is, the amplitude center of the mark / space of cvT and the amplitude center of the mark / space of dvT are far apart by the value H. (The value H is substantially equal to the value K.)
This value H is referred to as asymmetry in the DVD-RAM standard. If this value is increased, the quality of recording and reproduction is reduced. Therefore, the upper limit and the lower limit of the value H are defined around the value 0. That is, if the length of the long mark is not enough, D
In the VD-RAM, asymmetry occurs after the look-up table is updated, which causes a problem that signal quality deteriorates.

Even if the reproduced signal of FIG. 3A is sliced by another type of slicer, a problem occurs. For example, when slicing with a fixed level slicer that slices at the center value of the amplitude x, the mark is observed at a length of (c−Δ) vT, and the space is observed at a length of (c + Δ) vT. You. Independent Phase LockL on each of the leading and trailing edges
In the case of using oop (PLL), there is no problem even if the mark length is different from the predetermined length. However, in the case of using a PLL that shares a front edge and a rear edge like a DVD-RAM, the mark length is Is not observed at a predetermined length, it means that the edge position of the reproduction signal fluctuates immediately, and the reproduction jitter deteriorates.

As described above, regardless of which slicer is used, properly correcting the length of a long mark is indispensable for stably recording a high-quality mark on a recording medium.

In order to properly correct the length of the long mark, the length of the long mark may be detected and corrected so as to have an appropriate value. The following method can be considered as a specific example of the method of detecting the length of the long mark.

1) A continuous pattern of marks / spaces of length cvT is recorded on a recording medium and reproduced, and sliced using a slicer. At this time, the slice level is adjusted so that the mark and the space each have a length cT. The amount of difference (value K in FIG. 3A) between the adjusted slice position and the position of the amplitude center of the reproduced signal is detected, and the length of the mark having the length cvT is estimated based on the detected amount. A specific estimation method will be described with reference to FIG. When the value K is 0, the mark having the length cvT is the predetermined length cv.
It is T. The value K increases with a positive value (FIG. 3a).
The slice position 1 is on the paper with respect to the center position of the amplitude x. A) If the mark is too short. If the value K increases with a negative value (in FIG. 3A, the slice position 1 is below the center position of the amplitude x on the paper), the mark is too long. In this way, the mark length can be estimated by comparing the slice position with the center position of the amplitude x. In this case, it is necessary to adjust the mark length so that the deviation between the slice position 1 and the center position of the amplitude x finally falls within a predetermined error range.

2) A mark / space continuous pattern of length cvT is recorded and reproduced on a recording medium, and sliced using a slicer. At this time, in the slicer,
The slice level is set at the center position of the amplitude x like the slice position 2. If the time interval of the mark (and the space) is measured in this state, the length of the mark (and the space) can be known. In this case, it is necessary to finally adjust the mark length so that the measured mark length has a predetermined value.

The length of the long mark is measured, and if the length is deviated from a predetermined value, it is necessary to correct this. Such a correction method includes the following method.

1) If the mark length is excessive, the value of the power to be recorded is reduced to make the recording mark smaller. If the mark length is insufficient, the value of the power to be recorded is increased to increase the size of the recording mark.

2) The value of TSFP and TELP in FIG.
, One or both of them are changed.
That is, when the mark length is excessively large, the value of TSFP is increased or the value of TELP is decreased. When the mark length is insufficient, the value of TSFP is reduced or the value of TELP is increased. When adjusting the values of TSFP and TELP simultaneously, the adjustment amount of TSFP and TELP
And an adjustment method that always makes the adjustment amount equal to the adjustment amount at a certain fixed rate. TSFP adjustment amount and T
The method of making the adjustment amount of the ELP always equal has the effect of being relatively simple and easy to adjust.

In the above two methods of correcting the mark length,
The method 1) is not applicable to each element of the lookup table, but is effective in selecting a recording power suitable for the entire lookup table. The method 2) is effective when the recording power is fixed and an optimum look-up table at the recording power is formed.

According to the above-described method, the length of the long mark can be optimized, and the subsequent update of the look-up table has the effect of always forming a stable and highly reliable recording mark. In addition, even if the recording conditions of the recording device are different, the recording conditions can be optimized according to the characteristics of the device.
The compatibility in recording can be increased, and there is an effect that a highly reliable recording device with good compatibility can be configured.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram of the information storage device. For the sake of explanation, the information storage device has a recording medium 100
Is shown. Although the recording medium 100 is indispensable for storing information, the recording medium 100
Can be removed or attached to the information storage device as needed.

In FIG. 4, a chucking mechanism 112 is mounted on a rotating shaft 111 of a motor 110 mounted on a housing 108, and the chucking mechanism 112 holds the recording medium 100. Chucking mechanism 112
Is a mechanism for holding the recording medium 100. The motor 110, the rotating shaft 111, and the chucking mechanism 112 constitute a moving mechanism for relatively moving the recording medium 100 and the energy beam.

A rail 115 is attached to the housing 108. A rail guide 116 guided by the rail 115 is attached to the case 117. A linear gear 119 is attached to the case 117,
The rotary gear 120 is attached to the linear gear 119. By transmitting the rotation of the rotation motor 118 attached to the housing 108 to the rotation gear 120, the case 117
Moves linearly along the rail 115. The direction of this linear motion is substantially the radial direction of the recording medium 100.

A magnet 121 is attached to the case 117. The case 117 includes an objective lens 136.
To the substantially normal direction of the recording surface of the recording medium 100 and the recording medium 1
The objective lens 136 is attached via a suspension 123 that can move only in two directions of the radial direction 00. The objective lens 130 has a magnet 121.
The coil 122 is mounted so as to substantially oppose. By passing a current through the coil 122, the objective lens 136 can move in two directions, a substantially normal direction of the recording surface of the recording medium 100 and a substantially radial direction of the recording medium 100, due to a magnetic effect. The rail 115, the rail guide 116, the case 117, the magnet 121, the suspension 123, the coil 122, and the objective lens 136 constitute a positioning mechanism for positioning the energy beam at a predetermined position on the recording medium 100.

The case 117 is provided with a semiconductor laser 131 as an energy beam generator. The energy beam emitted from the semiconductor laser 131 passes through the collimator lens 132 and the beam splitter 133, and passes through the objective lens 136. Part of the light emitted from the objective lens 136 is reflected by the recording medium 100, passes through the objective lens 136, is reflected by the beam splitter 133, is collected by the detection lens 134, and is detected by the photodetector 135. Is done. The photodetector 135 has a light receiving area divided into a plurality. The light intensity detected in each light receiving area is amplified and calculated by the amplifier 152, and information (servo signal) and information on the relative positional relationship between the light spot collected by the objective lens 136 and the recording medium 100 are recorded. A read signal is detected. The servo signal is sent to the servo controller 151. The read signal is sent to the slicer 170 to be binarized, and the binarized signal is sent to the decoder 153 and the time interval measuring circuit 171.

When the recording medium 100 is mounted on the information storage device and the chucking mechanism 112 fixes the recording medium 100, the detector 140 operates and sends a signal to the system controller 150. System controller 150
Receives the command and controls the motor 110 to control the recording medium 1
00 is rotated to an appropriate number of revolutions. Further, the system controller 150 controls the rotation motor 118 to position the case 117 at an appropriate position. In addition, the system controller 150
Is emitted, and the servo controller 151 is operated to operate the rotary motor 118 or to supply a current to the coil 122 to position the focal spot formed by the objective lens 136 at a predetermined position on the recording medium 100.
Next, the servo controller 151 sends to the system controller 150 a signal that the focal spot is formed on the recording medium 100. The system controller 150 gives an instruction to the decoder 153 to decode a signal to be read. If the track to be read is not the information track of the control data zone, the system controller 150 gives an instruction to the servo controller 151 so that the focal spot is positioned at the information track of the control data zone. As a result of the above operation, the system controller 150 reads the information track in the control data zone and reads the medium information related to recording.

Information on the recording strategy described with reference to FIG. 1 is written in the information track of the control data zone. The recording power level, the temporal relationship of each recording pulse, the look-up table, and the recommendation of adaptive control are used to determine the information of which method.
50 reads from the recording medium 100. The system controller 150 writes the parameters of these recording strategies,
Parameter table of signal processing circuit 154, delay circuit 1
55 and the current sink amount parameter of the current sink 156. Depending on the method of selecting the adaptive control, the way of writing the table of the delay circuit 155 is different, or the switch of the delay circuit 155 is switched to realize the operation of each adaptive control method described with reference to FIG.

The system controller 150 controls the recording medium 1
00, and read them into the parameter table of the signal processing circuit 154 and the delay circuit 15.
5 and the current sink amount parameter of the current sink 156 are written in the recording medium 100.
May be in a writable state only. For example, when the write protect switch existing in the case of the recording medium 100 is set to a write-protected position, or when the host controller of the information storage device instructs the write-protection, the recording medium 100 is in the write-protected state. In this case, a series of operations such as reading the parameters of the recording strategy can be omitted. In order to detect the write protection switch, a detection switch 141 is attached to the housing 108, and sends a signal to the system controller. In the recording prohibited state, by stopping the reading operation of the parameters of the recording strategy, the preparation time from when the recording medium 100 is fixed to the chucking mechanism 112 to when the recording medium 100 can be reproduced can be shortened.

When an instruction to reproduce information is sent from the upper controller via the input connector 159, the system controller 150 gives an instruction to the servo controller 151 to position the focal spot at an appropriate position on the recording medium 100. After the signal obtained by the photodetector 135 is decoded by the slicer 170 and the decoder 153, the information read through the output connector 158 is sent to the host controller.

When an instruction to write information and information to be written are sent from the upper controller via the input connector 159, the system controller 150 gives an instruction to the servo controller 151 to set an appropriate focal spot on the recording medium 100. Position in position. The information to be written passes through the signal processing circuit 161 and passes through the NRZI.
It is converted into a signal. The signal converted into the NRZI signal passes through the signal processing circuit 154 and is converted into a plurality of appropriate pulse trains. These pulse trains are applied to the delay circuit 155
Through to the current sink 156. Here, the signal processing circuit 161 and the signal processing circuit 154 constitute a signal processing circuit that converts information to be written into a train of recording pulses.

A constant current source 157 is connected to the semiconductor laser 131, and the semiconductor laser 131 and the current sink 15 are connected.
6 so that the sum of the current consumed is always constant. A plurality of current sinks 156 are connected to the constant current source 157. Whether the current sink 156 operates and sinks current depends on the signal generated by the signal processing circuit 154 and passing through the delay circuit 155. Current sink 15
6 operates, a part of the current output from the constant current source 157 is absorbed by the current sink 156, and as a result, the amount of current flowing into the semiconductor laser 131 decreases. Thereby, the energy level of the energy beam emitted by the semiconductor laser 131 is changed. Signal processing circuit 1
The 54 and the delay circuit 155 operate the plurality of current sinks 156 at appropriate timings to realize the recording strategy shown in FIG.

In order to perform the above operation, the information recording apparatus is externally supplied with power through the terminal 160.

When the necessity of information writing occurs or before the information writing occurs, the look-up table for controlling the leading edge and the trailing edge in the information writing is optimized or updated. Sometimes. However, prior to the optimization or update of the lookup table, the length of the long mark may be optimized or updated for the reason described with reference to FIG. In such a case, the system controller provides the signal processing circuit 154 with the recording mark having the length cvT and the length cvT.
The recording pattern is formed on the recording medium 100 by sending a recording pattern in which the spaces appear alternately and continuously. However, it is assumed that the length of the cvT mark or space is at least half the length of the energy beam in the direction of the relative movement between the energy beam and the recording medium. Next, the recorded mark is reproduced, and the reproduced signal is sent to the time interval measuring circuit 171 after being binarized by the slicer 170. If the slicer is the Duty Feed Back slicer described in FIG.
The slicer 170 sends the slice level obtained by the Duty Feed Back and the amplitude center position of the reproduction signal input to the slicer to the system controller 150. In response to this, the system controller 150 sends a signal to the delay circuit 155 or the current sink 156 to correct the mark edge position of the long mark by the method described with reference to FIG. 3, and corrects the mark edge position. Again, the system controller 150
Record the mark / space of the length of vT on the recording medium, and
y Feed Back The slice level of the slicer is compared with the center of amplitude, and recording and evaluation are repeated until the slice level reaches a predetermined value within a predetermined error. When the slicer is the slicer of the fixed slice level described with reference to FIG.
70 sends the mark (and space) length information to the system controller 150. System controller 15
0 receives this signal and sends a signal to the delay circuit 155 or the current sink 156 to correct the mark edge position of the long mark by the method described with reference to FIG. 3 to correct the mark edge position. Again, the system controller 150 records the mark / space of the length of cvT on the recording medium, corrects the length of the recording mark (and space), and keeps the recording mark length at a predetermined value within a predetermined error. Repeat recording and evaluation. By repeating the measurement of the length of the recording mark (and the space) and the correction of the edge position of the long mark as many times as necessary in this manner, it is possible to determine the optimum writing condition of the long mark on the given recording medium 100 when necessary. Can be obtained. By updating the look-up table based on the optimized long mark, an optimum look-up table can always be created when needed. As a result, there is an effect that information can always be stably and reliably written into the recording medium 100.

When the slicer 170 is a fixed slice, the time interval measuring circuit 171 is used to measure the length of the mark (and the space). This can be considered as an example of a circuit having a function of a time interval analyzer (TIA). By selectively measuring the average value of the time interval from the leading edge to the trailing edge only for the portion corresponding to the mark, the length of the mark can be measured. As an example of such a circuit, a circuit that measures an edge interval only when a code (or level) corresponding to a mark appears while looking at a code (or level) of a reproduced signal (or a binary signal). Can be considered.

When all the edge intervals are measured without distinguishing the mark and the space, for example, the mark length becomes (c
−Δ) T, the space length is (c + Δ) T, so the TIA measurement result shows the peak of the edge variation centered on the average value (c−Δ) T and the average value (c + Δ) There are two peaks, that is, a peak of edge variation around T. When the center value of the jitter distribution is considered in consideration of all two peaks, this is cT. For this reason, an average value of the mark length cannot be obtained simply by looking at the average value of the edge intervals. In this case, instead of the average value of the edge intervals, the variation of the edge intervals around cT may be observed. That is, if the mark length is shifted, the edge variation becomes two peaks, and the edge variation rapidly increases. Therefore,
The edge jitter is observed, and when this is minimum, the mark length and the space length are equal,
This is the case where the mark length has been optimized. However, in the jitter observation, when the jitter increases, it is unknown whether the mark is long or short. Therefore, a procedure such as observing the edge variation while changing the edge position is required.

As another example of a method of measuring all edge intervals without distinguishing between marks and spaces, time (c-α)
There is a method of counting the number of edge intervals between T and time (c + α) T. In this case, when the edge jitter increases, the number of edge positions falling within the time interval decreases, and thus the jitter increases.

As another example of a method for measuring all edge intervals without distinguishing between marks and spaces, a time interval (c−
The counter 1 counts the number of edge intervals between (α−β) T and time (c−α) T, and calculates the time interval (c−α).
The counter 2 counts the number of edge intervals between α) T and time (c + α) T, and calculates the time interval (c + α) T
From the time (c + α + β) T, the counter 3 counts the number of edge intervals, and the value obtained by subtracting the result of the counter 1 and the result of the counter 3 from the result of the counter 2 corresponds to the edge jitter. Prove.

[0066]

According to the present invention, even in a high-density recording situation in which the shortest recording mark length is less than the recording spot radius, it is possible to always stably position the recording mark edge position at a predetermined position. There is an effect that information can always be stably and reliably recorded on a recording medium.
Further, even if the recording conditions of the recording device are different, the recording conditions can be optimized according to the characteristics of the device, so that the compatibility in recording can be increased, and the recording device having high compatibility and high reliability can be obtained. There is an effect that can be configured.

[Brief description of the drawings]

FIG. 1 shows an example of a temporal change in a power level of an energy beam applied to a recording medium when information is recorded on the recording medium.

FIG. 2 shows an example of a specific method of updating a lookup table.

FIG. 3 shows a problem in updating a look-up table, and a method of solving the problem will be described with reference to FIG.

FIG. 4 shows a specific example of an information recording apparatus using the present invention.

[Explanation of symbols]

100: recording medium, 108: housing, 110 ...
・ Motor, 111 ・ ・ ・ Rotating shaft, 112 ・ ・ ・ Chucking mechanism, 115 ・ ・ ・ Rail, 116 ・ ・ ・ Rail guide, 117 ・ ・ ・ Case, 118 ・ ・ ・ Rotating motor, 119 ・ ・ ・ Linear gear , 120 ... rotating gear, 1
21 ... magnet, 122 ... coil, 123 ... suspension, 130 ... objective lens, 131 ...
Semiconductor laser, 133 ... beam splitter, 134
... Detection lens, 135 ... Photodetector, 136 ...
Objective lens, 140: detector, 141: detection switch, 150: system controller, 151
... Servo controller, 152 ... Amplifier, 15
3 ... decoder, 154 ... signal processing circuit, 155
... Delay circuit, 156 ... Current sink, 157 ...
・ Constant current source, 158 ... output connector, 159 ...
Input connector, 160 terminal, 161 signal processing circuit, 170 slicer, 171 time interval measurement circuit.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Hiroyuki Minemura 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. F-term in Hitachi Multimedia Systems Development Division (Reference) 5D090 AA01 BB05 CC01 CC16 DD03 DD05 FF07 FF11 GG29 HH01 KK05 5D119 AA22 BA01 BB04 DA01 DA11 HA36

Claims (7)

[Claims] 1. A first state at a first power level of an energy beam and a second state higher than the first power level.
Using a recording medium that can be brought into the second state at a power level of, and moving the energy beam and the recording medium relative to each other and irradiating the recording medium with the energy beam. A method for recording information on said recording medium by forming said state and said second state on said recording medium at predetermined lengths and intervals, wherein said method is lower than said second power level. When a third power level is provided, and the area in the second state having a specific length is formed on the recording medium, the period of the third power level is mixed with the period of the second power level. In the method of recording information in which the energy beam is multi-pulsed and the energy beam is irradiated onto the recording medium, the timing adjustment of the leading pulse or the timing of the last pulse may be performed. To perform both, forming an area in the second state having a length of at least half the length of the energy beam in the relative movement direction of the energy beam and the recording medium on the recording medium. And measuring the length of the second state region having a length equal to or more than half the length of the energy beam from the reproduction signal, and measuring a length equal to or more than half the length of the energy beam. In the case where the length of the second state area having the length is different from the predetermined length, the second state area can be adjusted by using the timing adjustment of the first pulse or the timing adjustment method of the last pulse. An information recording method, comprising: adjusting a timing of a multi-pulse when forming an image. 2. The method of adjusting the timing of the leading pulse, comprising: a timing adjusting method of adjusting a timing at which an energy beam reaches the second power level in a leading pulse of the multi-pulse train; 2. The information recording method according to claim 1, wherein the method is a timing adjustment method that adjusts a timing at which the energy beam departs from the second power level, or a timing adjustment method that includes both of them. 3. The method of adjusting the timing of the final pulse, the timing adjusting method 3 adjusting the timing at which the energy beam reaches the second power level in the final pulse of the multi-pulse train, or the timing adjusting method of the final pulse of the multi-pulse train. 3. The information recording method according to claim 1, wherein the information recording method is a timing adjustment method that adjusts a timing at which the energy beam departs from the second power level, or a timing adjustment method that includes both of them. . 4. An energy beam generator, and a power adjustment capable of setting a power level of an energy beam generated by the energy beam generator to a first power level and a second power level higher than the first power level. A mechanism and the second state at a first state at the first power level.
A holding mechanism capable of holding a recording medium capable of entering the second state at a power level of; a moving mechanism capable of relatively moving the energy beam and the recording medium; An information recording apparatus having a positioning mechanism capable of irradiating a predetermined location of the recording medium with a signal processing circuit for changing information to be recorded to a power level of the energy beam, wherein the power adjustment mechanism is Having a third power level lower than the second power level, and forming the area in the second state to a specific length when forming the area in the second state on the recording medium; In this case, the power adjustment mechanism has a function of multiplying the energy beam by mixing the period of the third power level with the period of the second power level. An information recording apparatus characterized in that it has a head pulse timing adjusting means or a final pulse timing adjusting means, or both, and the relative position between the energy beam formed on the recording medium and the recording medium. From the reproduction signal of the second state region having a length equal to or more than half the length of the energy beam in a different moving direction, the second state region having a length equal to or more than half the length of the energy beam Means for measuring the length of the first pulse timing adjustment means when the length of the region in the second state having a length equal to or more than half the length of the energy beam is different from a predetermined length. Information that adjusts the timing of a multi-pulse when forming the second state region using the final pulse timing adjusting means or both. Recording device. 5. The head pulse timing adjusting means, comprising: a timing adjusting means for adjusting a timing at which an energy beam reaches the second power level in a head pulse of a multi-pulse train; or an energy beam in a head pulse of the multi-pulse train. The information recording apparatus is characterized in that the information recording device is a timing adjusting means 2 for adjusting the timing of departure from the second power level or a timing adjusting means comprising both of them. 6. The final pulse timing adjusting means includes a timing adjusting means for adjusting a timing at which the energy beam reaches the second power level in a last pulse of the multi-pulse train, or an energy beam in the last pulse of the multi-pulse train. The information recording device is a timing adjusting means 4 for adjusting the timing of departure from the second power level or one or both of them. 7. A recording method in which an energy beam is multi-pulsed and at least one edge position of a first pulse and a last pulse is controlled with reference to a table to record information on a recording medium, wherein a long mark and a long space are repeated. Information using a pattern, measuring a mark length from a slicer signal or an edge interval measurement result, correcting the timing of at least one of the first pulse position and the last pulse position using the result, and updating the table. Recording method.