JP2000149262A - Information recording method and information recording device - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] In a rewritable digital video desk (DVD) using a phase-change recording film, the recording characteristics are changed in response to a change in recording characteristics due to a temperature change and a temporal change. Ensure recording / playback compatibility between devices. The energy beam has a first state at a first power level and a second state higher than the first power level.
In order to set the second state at the power level, the timing adjustment of the pulse train is performed by the energy adjustment mechanism.

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 recording / erasing method for a rewritable recording film is, for example, a method in which an exchange-coupling two-layer film is used as a recording film as disclosed in JP-A-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.

Accordingly, it is an object of the present invention to use the same spot as the above-mentioned conventional one, and to maintain the compatibility with the conventional one, to perform accurate recording for further improving the density and to achieve the recording compatibility. It is to provide a method and an information recording device. Particularly, in a recording method having adaptive recording control in which the irradiation timing of a recording pulse is changed according to a combination of information to be recorded, a stable mark with little fluctuation is obtained. Further, even if the recording characteristics vary due to a plurality of recording phase replacements, a stable mark with good compatibility is always formed in any recording apparatus.

[0007]

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 with the recording medium by relatively moving the energy beam and the recording medium, and the first power level and the second power level according to information on which the energy level is to be recorded. By forming a pulse train of an energy beam by changing between a plurality of power levels including a power level, the first state and the second state are formed on the recording medium at predetermined lengths and intervals. A method of recording information on the recording medium by performing the operation, wherein the energy beam corresponding to a head portion of the second state to be formed on the recording medium Timing adjustment method 1 for adjusting the timing of the pulse, or timing adjustment method 2 for adjusting the timing of the pulse of the energy beam corresponding to the end portion of the second state to be formed on the recording medium, In the information recording method, the timing value to be adjusted by the timing adjustment method 1 is a first combination of the length of the first state and the length of the second state. Being determined, the timing value to be adjusted by the timing adjustment method 2 is determined by a second combination of the length of the first state and the length of the second state, the first combination Are divided into a plurality of groups, and a uniform timing adjustment value determined for each of the plurality of groups of the first combination is determined based on the original timing adjustment value. Adding to the imaging value, dividing the elements of the second combination into a plurality of groups, and applying a uniform timing adjustment value determined for each of the plurality of groups of the second combination to the original timing. A method of recording information characterized by adding to a value.

(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. An information recording device having a signal processing circuit for changing the state, wherein the information processing device corresponds to a head of the second state to be formed on the recording medium. Timing adjusting means 1 for adjusting the timing of the energy beam pulse, or timing adjusting means 2 for adjusting the timing of the energy beam pulse corresponding to the end portion of the second state to be formed on the recording medium. Or, in the information recording apparatus having one or both of them, the timing value to be adjusted by the timing adjustment means 1 is the first value of the length of the first state and the second value of the length of the second state. 1, the timing value to be adjusted by the timing adjusting means 2 is determined by a second combination of the length of the first state and the length of the second state;
An arithmetic circuit that divides the elements of the first combination into a plurality of groups, and adds a uniform timing adjustment value determined for each of the plurality of groups of the first combination to an original timing value; Having
An arithmetic circuit that divides the elements of the second combination into a plurality of groups and adds a uniform timing adjustment value determined for each of the plurality of groups of the second combination to an original timing value; Having
Recording method of information characterized by the following.

[0010]

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

First, with reference to FIG. 1, 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. 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, 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 the 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.

The time which defines the 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.

[0021] 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. 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 device reads this look-up table and performs edge shift control using the information as a reference, so that information can be stably recorded.

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.

Peak Power, Bias Power 1, Bias Power
For the initial values of 2 and Bias Power 3, it is conceivable that the recommended values are read from the information track in the control data zone of the recording medium, and the values are determined with reference to them.

Here, it is assumed that a look-up table of an edge shift of a certain recording medium is given to a certain recording apparatus. This look-up table may be a value obtained by reading a look-up table value recorded at a predetermined location on an information recording medium, or may be a look-up table obtained by a recording device in some way. The recording device performs recording using this look-up table.However, the recording temperature changes during use and the recording characteristics change, or the recording characteristics vary between the recording positions. For example, a given look-up table may not always be the best look-up table for the current combination of printing characteristics and printing medium of the printing apparatus. That is, consider a case in which a problem occurs in lookup table compatibility due to a change in characteristics over time, a difference in characteristics between individual recording apparatuses, and the like. In such a case, it is considered that the recording device has the following options.

(1) Information is recorded using a given lookup table, and verification is performed. If the number of errors exceeds a predetermined value, it is determined that recording is difficult, and recording is abandoned.

(2) The recording device itself recreates the look-up table. However, generally speaking, the process of creating a lookup table is complicated,
In addition to the complexity of the recording device system, there is a problem that it takes time to create the lookup table.

(3) A simple correction is applied to a given look-up table, and the look-up table is simply corrected in a short time by a simple system.

Here, the method of the simple correction of (3) will be discussed, and a method of preventing the system from abandoning the recording as in (1) will be considered.

According to the study of the recording mark forming process,
-It has been found that the following simple correction method is effective in a phase change medium such as a RAM. That is, the look-up table is divided into a plurality of groups, a uniform timing adjustment value determined for each group is assigned to each group, and the uniform timing adjustment value of the lookup table already obtained is The adjustment value is added, and the data is entered as follows using the value of the lookup table obtained. This situation will be described with reference to FIGS.

FIG. 2 shows an example of a recording timing adjustment look-up table. Front edge timing (T
₂ shows a lookup table for _SFP ) correction and a lookup table for rear edge timing ( _TELP ) correction. Each element is shown here in the form of a matrix, and the leading edge lookup table uses M
_{i, j} (i = 1, 2, 3, 4; j = 1, 2, 3, 4), and N _{i, j} (i = 1,
2, 3, 4; j = 1, 2, 3, 4).
However, although both the matrices M and N have 4 × 4 elements, the effect of the present invention is not limited to the case of 4 × 4, and is effective for objects of different sizes.

In FIG. 2, i = 1 and i in M _{i, j}
= 2 elements group A, M _i, in _j i = 3 and i =
Four elements are grouped into group B. In addition, elements of i = 1 and i = 2 in N _{i, j} are group C
In addition, elements of i = 3 and i = 4 in N _{i, j} are grouped into a group D. Further, the group A has the uniform timing adjustment value a, the group B has the uniform timing adjustment value b, the group C has the uniform timing adjustment value c,
It is assumed that a uniform timing adjustment value d is assigned to the group D. Where a, b, c, d
Can be either positive or negative.

FIG. 3 shows the simple correction method (3). That is, the timing adjustment value assigned to each group is added to the element of each group, and the value is updated. With such a method of grouping and uniform correction within a group, the look-up table can be updated by a simple method.

In order to explain the physical meaning of such grouping, a DVD-RAM having a capacity of 4.7 GB on one side of a 120 mm disk is considered as an example. In phase change recording, the relationship between the size of the light spot and the size of the recording mark is a very important factor. DVD
-In a RAM device, the light spot radius is approximately 0.5μ
m. The 3T mark length is about 0.42 μm, the 4T mark length is about 0.55 μm, and the 5T mark length is about 0.68 μm. Here, 3T mark, 4
The T mark is approximately equal to or smaller than the light spot radius, and the T mark or larger is significantly larger than the light spot radius. Although the 4T mark is slightly larger than the light spot radius, here it is considered to be about the spot radius. In such a case, 3
A great difference appears between the T and 4T mark forming processes and the 5T or more mark forming processes. For this reason, when a recording compatibility problem occurs, it is more preferable to give different uniform correction values to the group having the mark length of 3T or 4T and the group having the mark length of 5T or more in the lookup table. The lookup table correction can be effectively performed. For these reasons, it is physically meaningful to classify the lookup tables and make uniform corrections for each group, which effectively works.

Here, the mark lengths of 3T and 4T are divided into one group, and the mark lengths of 5T or more are divided into another group. However, depending on the recording method and the characteristics of the information recording medium, they may be different. Various grouping methods are conceivable. It is also conceivable to divide into more groups and assign correction values to each group. (However, one group requires one or more lookup table elements.) Also, different grouping methods can be applied to the leading edge lookup table and the trailing edge lookup table. .
As a specific example of such various grouping, there is a method of dividing the mark length of 3T into one group and dividing the mark length of 4T or more into one group.
Further, there is a method of dividing the mark length of 3T, 4T, 5T into one group, and dividing the mark length of 6T or more into one group. Further, there is a method of dividing the mark length 3T into one group, the mark length 4T into one group, and dividing the mark length 5T or more into one group.

Although the compensation value is for each group, a simple arithmetic relationship may be used between the compensation values. For example, when the mark length is 3T and 4T as one group and the compensation value for this group is a, and the mark length is 5T or more as another group and the compensation value for this group is b. , A = C1 × b (where C1 is a constant) or a + C2 × b = C3
(However, C2 and C3 are constants)
There is a way to associate values with each other. In the meaning of such an arithmetic relationship, a small mark such as 3T or 4T is greatly affected by a decrease in recording compatibility.
A mark larger than T is generated due to a physical phenomenon that the influence is small. An example in which the mark length 3T is used as one group and the correction value for this group is set as a, and the mark length 4T is used as one group, and this group , The mark length 5T is a group, the mark correction value for this group is c, and the mark length 6T or more is a group, and the correction value for this group is e.
Consider the following relationship: That is, a = C4 × b, b = C
This is a geometric progression distribution such as 4 × c, c = C4 × e (where C4 is a constant).

Although the above is the grouping of the look-up table focusing only on the mark length, other grouping focusing on the preceding space length and the succeeding space length is also conceivable. As the length of the preceding space or the length of the succeeding space becomes shorter, the thermal interference between the recording marks increases, and it is necessary to strongly perform recording compensation.However, the value of the recording compensation is based on what recording characteristics the recording apparatus has. Also strongly depend on. When the recording compatibility decreases, the amount of recording compensation changes, and the physical phenomenon that the manner of this change depends on the length of the preceding space and the length of the following space is a physical phenomenon that is dependent on the length of the preceding space and the length of the following space. It has implications. For example, if the preceding space length (or the succeeding space length) is 3T as one group and the compensation amount is a
And the compensation amount is b with 4T as the leading space length (or subsequent space length) as one group, and the compensation amount as c with the preceding space length (or subsequent space length) of 5T or more as one group. Such a classification could be considered as an example. Further, a = C5 × b, b = C5 × c
(However, C5 is a constant), an arithmetic relationship between the compensation amounts can be considered.

Generally, when the recording compatibility deteriorates,
It is considered that both the mark length dependency and the preceding space and subsequent space length dependencies appear at the same time. Because of this,
Of the elements M _{i, j} and N _{i, j} of the leading pulse lookup table, (i, j) = (1,1), (1,2), (2,
1), (2, 2) into one group, (i, j) =
(1,3), (1,4), (2,3), (2,4),
(3,1), (3,2), (3,3), (3,4),
(4,1), (4,2), (4,3), (4,4) may be divided into one group, etc., and an arithmetic relation may be defined for the compensation value for each group. Conceivable.

The compensation value to be given for each group is
This is more effective if the value is obtained by the following procedure.

1) Recording / reproduction is performed by changing the recording power while keeping the ratio between all the power levels of the recording pulse constant. Then, the recording power is optimized so that the amplitude center of the long mark and the amplitude center of the short mark match (so that the asymmetry in the DVD-RAM standard becomes zero).

2) Recording and reproduction are performed while changing the compensation value given for each group, and the compensation value is optimized so as to minimize the jitter value.

Here, the reason for optimizing the recording power first as in (1) above is that when the recording compatibility is reduced, the recording power is deviated from the optimum point. This is because it is proper. Although a method of optimizing all or a part of the power levels of the recording pulse is also conceivable, here, as an example, the method of making the ratio between the power levels constant has been described above.

By using the above recording method,
Even if the recording characteristics of the recording apparatus fluctuate due to aging, temperature change, etc., a highly accurate look-up table for recording compensation can always be obtained with a simple procedure, and there is an effect that information can be always stably recorded. .

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 storage medium 10.
0 is shown. In order to store information, the storage medium 100 is indispensable.
0 is removed or attached to the information storage device as needed.

In FIG. 4, a chucking mechanism 112 is attached to a rotating shaft 111 of a motor 110 attached to a housing 108, and the chucking mechanism 112 holds the storage 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 rotary motor 118 attached to the housing 108 to the rotary gear 120, the case 11
7 moves linearly along the rail 115. The direction of this linear motion is substantially the radial direction of the storage medium 100.

A magnet 121 is mounted on 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 storage 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. A part of the light emitted from the objective lens 136 is reflected by the storage 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 storage medium 100. 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 storage medium 100 is attached to the information storage device and the chucking mechanism 112 fixes the storage 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 storage medium 1
00 is rotated to an appropriate number of revolutions. Further, the system controller 150 controls the rotating motor 118 to position the case 117 at an appropriate position. Further, the system controller 150 controls the semiconductor laser 13.
1 as well as the servo controller 151 to operate the rotary motor 118 and the coil 123
And a focal spot formed by the objective lens 136 is positioned at a predetermined position on the storage medium 100. Next, the servo controller 151 sends a signal to the system controller 150 that the focal spot has been formed on the storage medium 100. System controller 150
Gives an instruction to the decoder 153 and decodes the 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,
The focal spot is positioned on 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 relating to 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 storage 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 storage 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 storage medium 100.
May be in a writable state only. For example, when the write protect switch existing in the case of the storage medium 100 is set to the write-protected position, or when the host controller of the information storage device instructs the write-protection, the storage 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 for information reproduction is sent from the host 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 storage 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 storage 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 supplied with power from the outside through the terminal 160.

When the necessity of information writing occurs or before the information writing occurs, the power level of the energy beam at the time of information writing may be optimized or the value may be updated. Further, the leading edge timing correction look-up table and the rear edge correction look-up table at the time of writing may be optimized or the value may be updated. In such a case, the system controller sends an appropriate recording pattern to the signal processing circuit 154, and the recording medium 10
A record mark row is formed on the zero. After that, the recording mark is reproduced, and the reproduction signal is binarized by the slicer 170 and sent to the time interval measuring circuit 171. The time interval measuring circuit 171 fluctuates the reproduced signal, that is, measures the amount of jitter, and sends the result to the system controller 150.
The system controller 150 changes the recording power in accordance with the procedure described in the description of FIG. 2 based on the measurement result of the jitter value, and the system controller sends the appropriate recording pattern to the signal processing circuit 154 again to perform recording. A recording mark sequence is formed on the medium 100 by using a new recording power. In this way, by repeating the measurement of the reproduction jitter and the update of the recording power accordingly, the required number of times,
The optimum recording power for writing to the given storage medium 100 can be created when needed. Also,
The system controller sends an appropriate recording pattern to the signal processing circuit 154, and forms a recording mark sequence on the recording medium 100. After that, the recording mark is reproduced, and the reproduction signal is binarized by the slicer 170 and sent to the time interval measuring circuit 171. The time interval measuring circuit 171 fluctuates the reproduced signal, that is, measures the amount of jitter, and sends the result to the system controller 150. If the obtained jitter value is insufficient, the system controller 150 assigns the compensation value assigned to each of the groups of the timing correction lookup tables for the leading edge and the trailing edge according to the procedure described in the description of FIG. Then, the system controller sends the appropriate recording pattern to the signal processing circuit 154 and forms a recording mark sequence on the recording medium 100 using the new recording power. As described above, by repeating the measurement of the reproduction jitter and the update of the compensation value associated with the reproduction jitter, it is possible to create a look-up table for optimal writing to the given storage medium 100 when necessary.

What is the time interval measuring circuit 171?
A circuit having the function of a time interval analyzer (TIA) can be considered as an example. As another example,
A PLL (Phase Lock Loop) is applied to the digital signal binarized by the slicer 170, and an error signal of the PLL (the difference between the edge position of the clock generated by the PLL and the edge position of the binarized digital signal) is generated. There is a method in which the magnitude of the (matching amount) is used as the amount of jitter of the binarized digital signal. Since the PLL circuit is indispensable when decoding the reproduction signal by the decoder 153, using the error signal of the PLL has an effect that it is not necessary to implement a particularly novel TIA in the information recording device. As another example, the digital signal binarized by the slicer 170 is compared with a recording pattern given to the signal processing circuit 154 at the time of writing, and the amount of mismatch is regarded as an error pulse, and the frequency of the error pulse is determined. And the amount of jitter of the binarized digital signal. Even in this case, even if a specially new circuit is not inserted in the information storage device,
There is an effect that the amount of jitter of the digitized signal can be evaluated.

[0064]

According to the present invention, even if the recording characteristics of the recording apparatus fluctuate due to aging, temperature change, etc., a highly accurate look-up table for the recording compensation can be always obtained by a simple procedure, and it is always stable. This has the effect of recording information. In addition, even if various recording apparatuses having different recording characteristics are used, there is an effect that a recording mark can always be stably formed with high compatibility on the same recording medium.

[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 a specific example of a lookup table and a specific example of grouping.

FIG. 3 shows an example of a specific method of updating a lookup table.

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

[Description of Signs] 100 ... recording medium 108 ... housing 110 ... motor 111 ... rotating shaft 112 ... chucking mechanism 115 ... rail 116 ... rail guide 117 ... Case 118: rotary motor 119
・ Linear gear 120 ・ ・ ・ Rotating gear 121 ・ ・ ・ Magnet 12
2 Coil 123 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 153-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 .

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Maeda 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside the Hitachi, Ltd. Central Research Laboratory (72) Inventor Hiroyuki Minemura 1-280 Higashi Koikebo, Kokubunji-shi, Tokyo Central Research Laboratory (72) Inventor Yasushi Miyauchi 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Hitachi Central Research Laboratory Co., Ltd. (72) Inventor Tsuyoshi Toda 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd. F term in the system development headquarters (reference) 5D090 AA01 BB05 CC01 CC05 CC18 DD03 DD05 EE02 FF08 FF11 FF36 GG33 HH01 KK04 KK05 5D119 AA13 AA22 BA01 DA01 HA36

Claims (2)

[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, the energy level is moved while the energy beam and the recording medium are relatively moved to irradiate the recording medium with the energy beam. The pulse train of the energy beam is formed by changing between a plurality of power levels including the first power level and the second power level in accordance with the information to be recorded.
A method of recording information on the recording medium by forming the state of the second state and the second state on the recording medium at predetermined lengths and intervals, the information being recorded on the recording medium. The timing adjusting method 1 for adjusting the timing of the pulse of the energy beam corresponding to the head of the second state, or the second method to be formed on the recording medium.
The timing adjustment method 2 for adjusting the timing of the pulse of the energy beam corresponding to the terminal portion of the state of
In one or both of the information recording methods, the timing value to be adjusted by the timing adjustment method 1 is a first value of the length of the first state and a first value of the length of the second state. The timing value to be adjusted by the timing adjustment method 2 is the first value.
Is determined by the second combination of the length of the state and the length of the second state, dividing the elements of the first combination into a plurality of groups, Adding a uniform timing adjustment value determined for each group to the original timing value, dividing the elements of the second combination into a plurality of groups, and setting each of the plurality of groups of the second combination And adding a uniform timing adjustment value determined for each group to the original timing value. 2. 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 comprising: a positioning mechanism capable of irradiating a predetermined position on the recording medium with a signal; and a signal processing circuit for changing information to be recorded to a power level of the energy beam. The timing adjustment means 1 for adjusting the timing of the pulse of the energy beam corresponding to the head of the second state to be performed, or the terminal corresponding to the end of the second state to be formed on the recording medium. It is characterized by having timing adjusting means 2 for adjusting the timing of the pulse of the energy beam, or one or both of them. In the information recording device, the timing value to be adjusted by the timing adjusting means 1 is determined by a first combination of the length of the first state and the length of the second state. The timing value to be adjusted in is determined by a second combination of the length of the first state and the length of the second state, dividing the elements of the first combination into a plurality of groups, An arithmetic circuit for adding a uniform timing adjustment value determined for each of the plurality of groups of the first combination to an original timing value;
Having an arithmetic circuit that divides the elements of the combination into a plurality of groups, and adds a uniform timing adjustment value determined for each group to each of the plurality of groups of the second combination to the original timing value; Recording method of information characterized by the following.