JP3225033B2 - Optical disk information writing control method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk information writing control method and apparatus, and more particularly to an optical disk apparatus for writing / reading information with a laser beam. And a device for controlling the writing.

[0002]

2. Description of the Related Art In recent years, with the increase in the capacity of computer systems, expectations for optical disks such as magneto-optical disks and phase-change optical disks as rewritable large-capacity files have increased. For this reason, an optical disk device for optically recording a large amount of document data and image information (image information) on a disk-shaped medium has been developed.
There are products aimed at the A market.

[0003] Information recording on an optical disk is performed by a thermal effect of laser beam irradiation on the disk medium.
For example, it is performed by reversing the magnetization of the medium or changing the crystal state of the medium. Of the recording methods, especially in a so-called long hole recording in which the length of a write bit (for example, laser irradiation) and a non-write bit (for example, laser non-irradiation) carry information, it is necessary to write an accurate bit shape on a medium. Is particularly important in reducing read errors and increasing device reliability.

The optical disk to which the present invention is applied includes a magneto-optical disk as long as the optical disk is of a long-hole recording type.

FIG. 30 shows a signal of a compact disk format (hereinafter referred to as a CD signal) as an example of a long hole recording. In this example, a High signal ("H") and a Low signal ("L") are 3τ to 11τ. (Τ is unit cycle = 230
ns), and the lengths of High and Low carry information.

In a conventional optical disk device, for example, for a 5τ high signal, 5τ (230 ns × 5 = 1)
Writing is performed on the medium by a method of irradiating laser for a time of 150 ns) and not irradiating laser for a Low signal.

In this case, since the medium is rotating at a constant speed, the pulse width nτ (n = 3 to 11) of the write information is represented by the bit length nL (L: time τ corresponding to the time τ) on the medium. Unit length) and recorded. An example of this state is shown in FIGS. 31 (a) and 31 (b).

However, in such a conventional optical disk information writing control method and apparatus, if the rotation speed of the medium is reduced (L is reduced) in order to perform higher-density recording, the bit is not changed. Due to the influence of heat generated at the time of writing, for a long bit such as n ≧ 7, FIG.
A bit shape as shown in FIG. 1C is written, and there is a problem that a C / N ratio is deteriorated when reading information and a reading error occurs.

In order to cope with this problem, a laser beam corresponding to a High signal is applied intermittently (pulsed). For example, the following literatures (1) to (1) are used.
The method is disclosed in (6). (1) JP-A-63-160017 (2) JP-A-63-263632 (3) JP-A-62-229542 (4) JP-A-63-266632 (5) JP-A-63-266632 JP-A-63-153726 (6) JP-A-63-266633

[0010]

However, according to the above-mentioned known method, the deterioration of the C / N ratio when the rotation speed of the medium is reduced cannot be reduced to a certain level or less.

That is, when the rotation speed of the medium is reduced, not only the heat generated at the time of the bit writing but also the influence of the remaining heat (remaining heat) generated at the time of the immediately preceding bit writing becomes large. Therefore, the writing start position of the bit differs depending on the length of the inter-bit space (the immediately preceding space length), and as a result, the mark length fluctuates.

Although the above-mentioned known method provides a countermeasure against the heat of the write bit, no countermeasure against the residual heat from the immediately preceding bit is taken, and the countermeasure against the C / N ratio deterioration at the time of high density writing is sufficient. I can't say.

[0013] Further, as measures relating to the residual heat from the immediately preceding bit, (7) JP-A-63-269321 (8) JP-A-63-302424 (9) JP-A-64-59633 There is the technology described.

However, the contents described in the above publications (1) to (9) do not solve the problem of the present invention at all, as described later.

Each of the techniques described in the above-mentioned documents is specifically described as follows.

(1) Japanese Patent Application Laid-Open No. 63-160017 In this device, the means for controlling the laser light is configured so that the laser light is divided into a plurality of pulses and applied within a time corresponding to the length of the signal bit. The laser light control means divides the laser light according to the length of the signal bit, sets the leading pulse width of the divided laser light pulse to be larger than the succeeding pulse, and further divides the leading laser of the divided laser light pulse. The pulse intensity of the pulse is set to be larger than that of the subsequent pulse.

Therefore, although writing with pulsed laser light is described, no specific pulsing means is described at all, and the above problem has not been solved.

(2) In this device, the means for controlling the laser beam splits the laser beam immediately before the end of the period to be irradiated within a time corresponding to the length of the signal bit. It is configured to give the same two pulses, and the same effect as described in Japanese Patent Application Laid-Open No. 63-160017 is attempted to be further simplified. It cannot be solved.

(3) Japanese Patent Application Laid-Open No. 62-229542 A pulse oscillator for generating a pulse having a predetermined pulse width corresponding to a light beam irradiation time suitable for the recording sensitivity of a recording layer of a recording medium at a constant period; A gate circuit that controls the derivation of a pulse signal output from the pulse oscillator to a laser drive circuit in accordance with a recording pulse output from a recording pulse generator, wherein the laser drive circuit controls a laser by an output of the gate circuit. It controls the light output of the light source.

However, the present invention relates to means for pulsing a CD signal, and the pulse width is constant and cannot be changed within a recording pulse in principle.

(4) Japanese Patent Application Laid-Open No. 63-266632 In a method of recording information by irradiating an energy beam such as light or an electron beam to change the atomic arrangement of a recording medium, the center of the energy spot is located at the recording point. The recording point is formed by one or a plurality of pulses having a pulse width shorter than the time required to pass from end to end. However, writing is performed using a pulsed laser beam, and the pulse width is 3 bits long.
It is more preferable that the width be smaller than / 4, more preferable that the width be smaller than 1/2, and particularly preferable that the width be smaller than 1/4. No method of pulsing is described.

(5) Japanese Patent Application Laid-Open No. 63-153726 The energy amount of each radiation pulse in one group of continuous radiation pulses is determined by the temperature rise in the information medium caused by one radiation pulse and the energy increase. It is intended to determine the position within the group in consideration of the condition that the sum with the temperature already generated by the previous radiation pulse in the group is always constant. Composed of claims. This is an application filed by the co-author of the paper cited in the specification of the present application, and has almost the same content as the paper,
It cannot completely solve the problem (details will be described later).

(6) Japanese Patent Laying-Open No. 63-266633 It is disclosed that a write signal pulse is divided into a starting portion, an intermediate portion, and a terminating portion. However, the fact that the pulse width of each part can be set independently, and a pulse prohibiting means that prohibits the generation of each pulse independently is not disclosed, and as described later, for the purpose of obtaining an optimum write bit shape. Is not suitable and cannot completely solve the problem. Further, there is no description of controlling the length of the write signal in accordance with the immediately preceding space length, which is a main component of the present invention.

(7) Japanese Patent Application Laid-Open No. 63-269321 In the case where the laser light control means shortens the irradiation time of laser light when forming a long bit, or forms a bit having a short blank length immediately before. In addition, the irradiation time of the laser beam is shortened. Specific means for shortening the laser beam irradiation time when forming bits with a short blank length immediately before, assuming the formation of bits by melting the film, such as a CD master or write-once disc. Is not shown at all. Furthermore, this is normal writing, and no description is made on pulsed writing. Therefore, there is no suggestion of a specific technique capable of solving the above-described problem.

(8) Japanese Patent Application Laid-Open No. 63-302424 When laser light control means forms a bit having a short blank length immediately before, the laser light control means shortens the irradiation time of the laser light and reduces a bit having a long blank length immediately before. In the case of formation, the start of laser beam irradiation is hastened, and the contents are almost the same as in the technology described in the above-mentioned seventh gazette. There is no suggestion of a specific technology that can be solved.

(9) Japanese Patent Application Laid-Open No. 64-59633 In order to avoid a phenomenon in which the subsequent write bit diameter becomes large when the write interval is short in an optical disk device for bit position recording, the bit interval is detected. When the interval is short, the writing laser power is reduced. It is disclosed that the pulse interval is detected and the laser light amount is changed accordingly. However, this example is not a mark length recording but a bit position recording, and the recording method to be assumed is completely different. Therefore, the problem cannot be solved similarly to the techniques described in the above-mentioned publications (7) and (8).

Therefore, according to the present invention, even when high-density writing is performed, a reproduced signal having a good C / N ratio can be maintained by maintaining an accurate recording bit shape, that is, a recording bit of a predetermined shape whose writing start position is a specified position. It is an object of the present invention to provide an optical disk information writing control method and an optical disk information writing control method capable of obtaining the information.

[0028]

In order to achieve the above object, the method for controlling the writing of information on an optical disk according to the present invention achieves not only the effect of the heat generated during the bit writing but also the effect of the residual heat generated during the immediately preceding bit writing. Is also corrected.

That is, according to the present invention, the recording bit length is
The mark signal section is placed on the optical disk that records information
To write an information signal consisting of
Corresponds to the mark signal portion in the information writing control method of
Information signals to be transmitted are divided into a plurality of first to n-th (n (integer) ≧ 2)
With a series of pulse trains pulsed into pulses
In addition, the first pulse generating means is provided at the beginning of the series of
It can be generated by changing the setting of the amplitude of the first pulse.
A space immediately before the information signal corresponding to the mark signal section
The length of the information signal corresponding to the first signal space is the first space.
If it is long, a first pulse having a first amplitude is generated,
A second space length shorter than the first space length
For example, a first pulse having a second amplitude is generated,
The n-pulse generating means is configured to generate the second to n-th
Each pulse is generated and generated by the first pulse generating means.
A first pulse having an amplitude corresponding to the length of the space,
The second to n-th pulse generated by the second to n-th pulse generating means
By configuring the series of pulse trains with pulses,
The series of pulse trains is controlled according to the space length,
By applying a series of controlled pulse trains to the light irradiation means
Mark signal from which a reproduced signal with a good C / N ratio can be obtained
The writing of a part is performed. In addition, the present invention
Is an optical disk that performs information recording in which the length of the recording bit carries information.
The disc consists of a mark signal section and a space signal section.
In an information writing control method for writing an information signal,
A) Writable information signal corresponding to the mark signal section
A starting portion for rapidly raising the temperature of the medium to a desired temperature;
b) Maintain the elevated medium temperature in balance with heat dissipation
An intermediate portion, and c) a temperature generated upon completion of laser beam irradiation.
End part that keeps the descent at the specified condition.
The information signal corresponding to the mark signal section is
3 so that the pulse widths of
By pulsing each of the two parts,
Corresponding to the length of the information signal corresponding to the mark signal portion
Pulse into a plurality of first to n-th (n (integer) ≧ 2) pulses
And a series of pulse trains, corresponding to the mark signal section
When the length of the information signal changes according to the information,
To change the number of pulses in the middle part of the pulse train
None, the first pulse generating means is the head of the series of pulse trains.
Can be generated by changing the amplitude of the first pulse of
The space immediately before the information signal corresponding to the mark signal
The length of the information signal corresponding to the space signal portion is the first space.
The first pulse having the first amplitude
With a second space length shorter than the first space length.
If so, a first pulse having a second amplitude is generated, and a second pulse is generated.
To the n-th pulse generation means are the second to the second of the series of pulse trains.
n pulses, each of which is generated by the first pulse generation means.
A first pal having an amplitude corresponding to the generated space length
And the second to n-th pulse generation means.
By composing the series of pulse trains with the n-th pulse,
Controlling the series of pulse trains according to the space length,
Applying the controlled series of pulse trains to the laser irradiation means
This makes it possible to obtain a reproduction signal with a good C / N ratio.
The write signal section is written. Also,
The present invention provides a method for irradiating an optical disc medium with laser irradiation means.
Information recording in which the length of the recording bit bears information by irradiating the laser
Mark signal section and space signal section on the optical disc for recording
Optical disk information book for writing information signal composed of
Information corresponding to the mark signal portion in the embedded control device.
A space that recognizes the length of the space signal part immediately before the signal
Source recognition means, start part control signal, intermediate part control signal and
And an end control signal, and
Generates control signals corresponding to the space length recognized by the recognition means
Control signal generating means for performing, based on each of the control signals
Write the information signal corresponding to the mark signal section to the writable temperature.
The start part to quickly raise the temperature of the medium with
An intermediate part for maintaining the medium temperature in balance with heat radiation,
Prescribe the temperature drop that occurs with the end of the laser beam irradiation
Into three parts with an end part to keep
Each of them is pulsed, and the pulse signal is applied to the mark signal section.
The first to n-th (n (alignment) corresponding to the length of the corresponding information signal
A series of pulses pulsed into multiple pulses of (number) ≧ 2)
Pulsing means for generating a sequence, said pulsing means
Sets the amplitude of the first pulse at the beginning of the series of pulse trains.
It can be generated by changing the setting, and based on the control signal,
If the space length is the first space length, the first amplitude
And generates a first pulse having a length equal to the first space length.
If the second space length is shorter, the second space having the second amplitude
First pulse generating means for generating one pulse;
To generate the second to n-th pulses of the pulse train
N-th pulse generation means, and the first to n-th pulse generation means
Pulse output means for outputting the first to n-th pulses generated in
And a stage generated by the first pulse generating means.
A first pulse having an amplitude corresponding to a space length and the second pulse
To the second to n-th pulses generated by the n-th pulse generating means;
By configuring the series of pulse trains with
Controlling the series of pulse trains according to the length,
By applying a series of pulse trains to the laser irradiation means, C /
Of the mark signal portion from which a reproduced signal having a good N ratio can be obtained.
Writing is performed. Also, the present invention
An optical disk for information recording where the length of the recording bit carries the information
Information consisting of a mark signal section and a space signal section.
An information writing control device for writing a signal,
A space immediately before the information signal corresponding to the mark signal section
Space for recognizing the length of the information signal corresponding to the
Recognition means and a length of an information signal corresponding to the mark signal portion
Corresponding to the first to n-th (n (integer) ≧ 2)
A pulse that produces a series of pulsed pulses
Pulsing means, wherein the pulsing means comprises
Can be generated by changing the setting of the amplitude of the first pulse at the beginning of the pulse train
And if the space length is the first space length
Generating a first pulse having a first amplitude;
If the second space length is shorter than the space length, the second
First pulse generating means for generating a first pulse having a width
And the second to n-th pulses of the series of pulse trains are respectively emitted.
The second to n-th pulse generating means,
Outputting the first to n-th pulses generated by the pulse generating means
And a pulse output means.
A first pal having an amplitude corresponding to the generated space length
And the second to n-th pulse generation means.
By composing the series of pulse trains with the n-th pulse,
Controlling the series of pulse trains according to the space length,
Applying the controlled series of pulse trains to the laser irradiation means
This makes it possible to obtain a reproduction signal with a good C / N ratio.
Write of a peak signal portion is performed. here
In each of the pulses constituting the series of pulse trains,
The amplitude can be set independently according to the space length
Is preferred. Further, each pulse constituting the series of pulse trains described above.
The amplitude of each luz independently according to the space length
It is preferable to have means for setting. In addition, the present invention
In an information writing control method for writing an information signal composed of a mark signal portion and a space signal portion on an optical disc on which information is recorded in which the length of a recording bit carries information,
The information signal corresponding to the mark signal portion is formed into a series of pulse trains pulsed into a plurality of pulses, and the width of the first pulse at the head of the series of pulse trains is set immediately before the information signal corresponding to the mark signal portion. Wherein the control is performed in accordance with the length of the information signal corresponding to the space signal portion, and the controlled pulse train is applied to the light irradiation means to perform writing.

Further, the present invention relates to an information writing control method for writing an information signal comprising a mark signal section and a space signal section on an optical disk for recording information in which the length of a recording bit carries information. The information signal corresponding to the mark signal portion is formed into a series of pulse trains pulsed into a plurality of pulses, and the first pulse at the beginning of the series of pulse trains is formed.
The amplitude of the pulse is controlled according to the length of the information signal corresponding to the space signal portion immediately before the information signal corresponding to the mark signal portion, and the controlled pulse train is transmitted to the light irradiation unit. It is characterized in that writing is performed by applying voltage.

[0031]

Further, the present invention is, in the optical disk recording information length of recording bits carrying information, in the information write control method for writing information signal composed of mark signal parts and space signal parts, An information signal corresponding to the mark signal portion: a) a start portion for rapidly increasing the temperature of the medium to a writable temperature; b) an intermediate portion for keeping the increased temperature of the medium in balance with heat radiation; c) an end unit for maintaining a temperature drop caused by the end of laser beam irradiation under a predetermined condition; and an information signal corresponding to the mark signal unit under conditions where the pulse width of each pulse is suitable. By performing pulsing for each of the three portions, a series of pulse trains corresponding to the length of the information signal corresponding to the mark signal portion is formed, and the mark signal portion is compared with the pulse signal. When the length of the information signal to be is changed in correspondence with the information, without so changing the number of pulses of the intermediate portion of the pulse train, and the open
The width or amplitude of the first pulse at the beginning of the start is controlled in accordance with the length of an information signal corresponding to a space signal portion immediately before the information signal corresponding to the mark signal portion, and the controlled pulse train is characterized in that by applying the laser irradiation unit and to perform writing included.

[0033]

According to the present invention, there is provided an optical disk for performing information recording in which the length of a recording bit carries information by irradiating a laser onto an optical disk medium by a laser irradiating means, the information comprising a mark signal portion and a space signal portion. In an optical disk information writing control device for writing a signal, the mark signal is written.
Length of the space signal immediately before the information signal corresponding to the
And a start control signal,
Generate the inter-section control signal and the end control signal
To the space length recognized by the space recognition means
Control signal generating means for generating a plurality of start unit control signals
When the information signal corresponding to the mark signal part on the basis of the respective control signal, and a start portion to quickly raise the temperature of the medium to writable temperature, and the heat radiation balance temperature elevated medium holding And an end portion that keeps the temperature drop accompanying the end of the laser beam irradiation under predetermined conditions. Each of the three portions is pulsed to correspond to the mark signal portion. Pulsing means for generating a series of pulse trains corresponding to the length of the information signal,
When the start unit control signal is input, the
Controlling the starting portion for the width or amplitude of the first pulse of the head
A pulse for performing control according to the space length based on a signal
And column control means .

Also, according to the present invention, the length of the recording bit
The mark signal section and the optical disk for recording information
Information for writing the information signal composed of the pace signal section
The information writing control device corresponds to the mark signal portion.
Information corresponding to the space signal part immediately before the information signal
Space recognition means for recognizing the length of a signal, and the mark
Multiple pulses corresponding to the length of the information signal corresponding to the signal section
Pulsing to generate a series of pulsed pulses
Means, and the width or width of the first pulse at the beginning of the series of pulse trains.
Is the amplitude of the space recognized by the space recognition means.
Pulse train control means for controlling according to the length.
It is characterized by.

[0036] Here, it is preferable that the respective width or amplitude of each pulse constituting the front Symbol pulse train having means which can be set independently in accordance with the space length. Also, before Symbol pulse train control means, it is preferable to control at least a portion of the series of pulses in response to the radial position of the optical disc medium which writing is performed. Also, before Symbol space recognition means starts counting when the control signal indicating the start of the space signal part is input, the counter means stops counting when the control signal indicating the start of a mark signal part is input Having is preferred .

[0037] Also, the respective widths of the pulses forming the pre SL pulse train can be independently set in accordance with the space length are preferred. Also, it is preferable to control at least a portion of the series of pulses in response to the radial position of the optical disc medium which the write is performed. Also, when the control signal indicating the start of the space signal part is inputted starts counting, by a counter means for terminating the count when the control signal indicating the start of a mark signal part is input, the space signal part It is preferable to recognize the length of the corresponding information signal.
New Also, provided a control signal generating means for generating a plurality of start part control signal corresponding to the space length recognized in the previous SL space recognition means, said pulse control means, based on said start part control signal, the first It is preferable to control the pulse width or amplitude in accordance with the space length.
Also, good is that the respective amplitudes of the pulses forming the pre SL pulse train can be independently set in accordance with the space length
Good .

According to the present invention, the write signal of the recording bit is pulsed, and the length and / or amplitude of the pulse train of the pulsed write signal of the recording bit is set immediately before the write signal. It is controlled according to the length of a certain space signal. Therefore, the effect of heat generated at the time of writing the recording bit immediately before the recording bit can be effectively corrected, and a good bit shape can be obtained regardless of the mark length and the space length.

Therefore, even when high-density writing is performed, an accurate recording bit shape is written only by adding simple hardware, and a high-quality reproduced signal having a good C / N ratio can be obtained.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

"Analysis of Problems in the Prior Art" First, the present inventor examined an accurate analysis of the above-mentioned problems and a solution thereof. The first problem, that is, a phenomenon in which a normal bit shape is not written when the rotation speed of the medium is reduced to perform high-density recording, can be considered as follows. When the rotation speed of the medium is a normal rotation speed, the local temperature rise of the medium due to the laser beam irradiation and the temperature drop due to the heat radiation of the medium maintain a constant balance, and a boundary where writing by the thermal effect is performed (hereinafter, referred to as a boundary). The writing boundary substantially coincides with the laser beam. Thus, for example, 11
If a bit of τ is written, the length 11
A bit of L and width d (d: diameter of laser beam) is formed.

On the other hand, if the rotation speed of the medium is reduced for high-density recording, the laser beam irradiation energy per unit area increases, so that the temperature drop due to heat radiation cannot be made in time, and the heat gradually increases as the irradiation time increases. And heat flows out to positions before and after the beam irradiation position. Since there is a lower limit in the energy of the laser beam required to perform writing for a certain period of time due to the thermal effect, writing is performed with the energy of the laser beam reduced to 1/2 even when the rotation speed is reduced to 1/2. I ca n’t help but
The above phenomenon always occurs.

Therefore, when writing a long bit such as 7τ or more, the heat accumulation increases as the laser beam advances to the 2L position, 3L position, and 4L position, and the influence of heat on the adjacent position gradually increases. The writing boundary also extends beyond the laser beam diameter d. At the end of the bit, that is, immediately near the 7L position in the above example, the laser beam irradiation ends immediately, and the temperature drop due to heat radiation becomes dominant, so that the writing boundary becomes almost the beam diameter.

Considering such a model, FIG.
The bit shape shown in (c) can be explained. In particular, in a phase change type medium in which recording is performed by changing the reflectivity by changing the crystal state (crystal phase), the crystal state is changed by rapid cooling or slow cooling from the molten state, and High / Low information is written. The effect of heat flowing out of the location is significant.

As an example, consider a phase change type medium in which high information is written by rapid cooling. If the write bit length becomes longer than a certain level (for example, 7τ or more) and there is an influence of heat on an adjacent position, For example, at the 3τ position, it is affected by the flow of heat from the 4τ position.
Thereafter, the nτ position is sequentially affected by the flow of heat from the (n + 1) τ position, and as a result, the condition becomes not a rapid cooling but a slow cooling. In such a state, high information writing of a bit longer than a certain level becomes very unstable. In order to obtain a stable high write state even when writing a long bit, that is, to realize a stable quenching state, the laser beam is intermittently interposed between write bit lengths nτ (n = 3 to 11) ( It is effective to irradiate in a pulse form and write. See DJGravesteijn et al "Phase
-change optical data storage inGaSb ", Applied Optic
80n at 4.3MHz (τ = 230ns) frequency in s, 26 , 4772 (1987)
Writing with a pulse train having an s width is described.

The present inventors have written various High write bit lengths (hereinafter referred to as mark lengths) on a medium in accordance with the examples of the above-mentioned documents and observed the bit shapes. As a result, as described in the above document, in writing with a pulse train having a constant pulse width, even if the pulse width is changed or the optical power is appropriately changed, the mark length 3τ No pulse width condition to achieve a good bit shape over 11τ could be found. That is, in the case of the shortest mark length of 3τ, a good bit shape was obtained when writing was performed with three pulses having a pulse width of 180 ns. However, 11τ having the longest mark length was written with 11 pulses under this condition. In this case, the light energy is too large, and a bit-shaped abnormality similar to the writing by continuous light shown as the conventional example occurs.

Conversely, under a pulse width condition of 120 ns that gives a good bit shape in the case of 11τ, a bit of 3τ could not be written normally due to insufficient light energy.

The method of recording by changing the pulse width of the pulse train constituting the mark is described in
No. 66633. In this example of the disclosure, the pulse train is divided into three parts, a start end, an intermediate part, and an end, and the pulse width of the start end and the end is made larger than the pulse width of the intermediate part. However, in the method disclosed herein, when each part of the starting part (hereinafter referred to as a starting part), the intermediate part, and the ending part (hereinafter referred to as an ending part) is composed of a plurality of pulses, the pulse width of each pulse in each part is determined. Since it cannot be set independently, it is not suitable for the purpose of obtaining an optimum write bit shape under various combinations of pulse widths.

Therefore, the present inventor has considered a device described later which can independently set each pulse width of the pulse train constituting the mark, and writes various mark lengths under various combinations of pulse widths. Observation of the inserted bit shape was performed.

FIG. 1 shows an example of a suitable write pulse condition obtained from the above observation results and a write bit shape at that time. Specifically, FIG. 1A shows a 7τ Hig.
h information (mark) and 7τ low information (space) are repeated, and a pulse period T = τ (230 n
s) as a first pulse width of 200 ns and a second pulse width of 150 n
s (start), third pulse width of 120 ns, fourth to sixth pulse width of 100 ns (intermediate part), and seventh pulse width of 130 ns (end part). It is a thing. The bit shape was remarkably improved as compared with writing by a continuous laser beam (FIG. 30C).

FIG. 1B shows a space of 7τ, 1
For a mark of 1τ, the first pulse width is 200 ns, the second pulse width is 150 ns (start portion), the third pulse width is 120 ns, and the fourth pulse width is 100 ns.
The bit shapes written under the conditions from the 10th pulse width of 100 ns (intermediate part) to the eleventh pulse width of 130 ns (end part) are shown. Similarly, FIG. 1C shows a first pulse width of 200 ns and a second pulse width of 150 ns for a mark of a space 3τ of 7τ.
ns (start portion), the bit shape written under the condition of the third pulse width of 130 ns (end portion, in which case no intermediate portion pulse is output). In each case, good bit shapes were obtained as in FIG.

Considering the physical meaning of this experimental result, a part for rapidly increasing the medium to a writable temperature (starting part) The temperature increased at the starting part is balanced with the heat radiation of the medium. Keeping part (intermediate part) It can be interpreted as having three functions as described above: part keeping temperature drop caused by the end of laser beam irradiation under suitable conditions. Therefore, changing the length of the middle part by increasing or decreasing the number of pulses in the middle part when changing the mark length is merely changing the length of the part having the function of maintaining the temperature, regardless of the mark length. It can be fully understood that a good bit shape can be obtained.

However, FIG.
As shown in (a) and (b), a better bit shape can be obtained by making the pulse width of the first pulse wider than the other pulse widths.

In the experiments described so far, only the mark length has been focused on, and the space length has been kept constant for convenience. However, in an actual CD signal, 3τ is equal to 1
Information is recorded by a combination of a mark and a space having a length up to 1τ. Therefore, the space between the writing of the mark and the writing of the next mark is constantly changing between 3τ and 11τ. In particular, in a phase change type medium in which recording is performed by changing the crystal state by rapid or slow cooling of the medium, there is a concern that the effect of the residual heat when the immediately preceding bit is written is concerned.

In order to clearly understand the effect of the residual heat,
The space length was changed from 3τ to 11τ, and the change in the mark length was observed. FIG. 32 shows this state.

The recording medium is (In _0.40 Sb _0.60 ) _0.94 Ge _0.06
Using a recording film with a composition of
The experiment was performed under the condition of 1.2 m / s.

The horizontal axis shows the space length immediately before the target write mark, and shows the results when the write mark length is 3τ7τ and 11τ. In the figure, x indicates data for normal writing (laser power 5 mW) without pulsing, and o indicates data for pulsing (laser power 12 mW) under the preferable pulse conditions described above.

In the case of normal writing, the immediately preceding space length is 3
The difference in the write mark length between τ and 11τ is 300 ns (1.3
(equivalent to τ)), and it is impossible to determine the mark length correctly.

When pulse writing is performed, the difference between the write mark lengths in the case of the immediately preceding space lengths 3τ and 11τ is 150 ns, which is certainly improved. However, this value is very much equivalent to 65% of the value of τ (= 230 ns), and is 0.5, which is a criterion for determining each mark length at the time of reading.
Since it exceeds τ, all mark lengths cannot be correctly determined.

As described above, since the influence of the residual heat is great, the actual long-hole recording signal represented by the CD signal cannot be accurately written and read only by pulsing by the conventional technique.

The embodiment described below solves the above problems,
Write a long hole recording signal represented by a CD signal accurately,
An object of the present invention is to provide an optical disk information writing control method and apparatus capable of obtaining a high-quality reproduction signal having a good / N ratio.

First Embodiment FIGS. 2 to 7 show a first embodiment of an optical disk information writing control method and apparatus according to the present invention. FIG. 2 is an overall configuration diagram of the optical disc information writing control device. In this drawing, the writing control device is roughly divided into an input CD signal D ₀ (corresponding to a recording bit write signal), A first delay circuit (first delay means) 1 for delaying the CD signal D ₀ within a predetermined range
A second delay circuit (second delay means) 2 for further delaying the CD signal (first delay signal D ₁ ) delayed by the first delay circuit 1 within a predetermined range; 1. Control for generating a start control signal A, an intermediate control signal B, and an end control signal C from output signals (first and second delay signals D ₁ and D ₂ ) of the second delay circuits ₁ and _2. A signal generating circuit (control signal generating means) 3 and a start signal for writing a recording bit signal, that is, an input CD signal D ₀ by the control signals;
A pulsing circuit (pulsing means) 4 which divides the signal into three parts, an intermediate part and an end part, and generates a pulse corresponding to each part.
And a pulse train control circuit (pulse train control means) 10 that recognizes a space length immediately before the input CD signal D ₀ and controls the length of the pulse train according to the space length.

The pulsing output from the pulsing circuit 4 is input to the laser diode 5.
Generates a laser beam based on this pulsed output. The laser beam is focused through a lens 6 and
The optical disk medium 8 rotating about the center is irradiated to perform a long hole recording. The laser diode 5 and the lens 6 constitute a laser irradiation unit 9.

First delay circuit 1 and second delay circuit 2
For example, digital means such as a shift register which can obtain a delay synchronized with a clock is preferable, but analog means such as a delay line may be used. In this embodiment, the first delay time is described as τ, and the second delay time is described as 2τ. However, this is not essential, and the minimum space length (in the case of a CD signal, Should be 3τ) or less, and 1.5τ, 0.25τ
A decimal number may be used.

The details of the pulsing circuit 4 are shown in FIG. 3 and FIG. 3 shows only one set of pulsating circuits 4 for convenience. The circuit shown in FIG. 3 is required.

In FIG. 3, the pulsing circuit 4 includes a clear circuit 11, a counter 12, a delay circuit 13, and a decode circuit 1.
4, a pulse width setting circuit 15 and an OR gate 16 as an integrated circuit. The clear circuit 11 comprises a delay circuit 17, an inverter 18 and a NAND gate 19, and generates a signal for clearing the counter 12 in synchronization with the falling edges of the control signals A, B and C.
Output to the clear terminal. Control signals A, B, and C are input to a count enable terminal of the counter 12, and a pulsed clock is input to a clock terminal. Now, taking the case where the control signal A is first input to the counter 12 as an example, the counter 12 starts counting when the signal becomes “H”, and stops counting when it becomes “L”. At this time, a clear pulse having a pulse width determined by the delay time of the delay circuit 17 (for example, 50 ns) is applied from the clear circuit 11 to the clear terminal of the counter 12, and the content of the counter 12 is reset to "0".

Specifically, when a control signal A having a width of 2τ is input as shown in FIG.
→ 1 → 2 → 0. 2 which is the output of the counter 12
⁰ digit (A, A bar), 2 ¹ digit (B, B bar), 2 ^two digits (C, C bar), 2 ^3-digit (D, D bar) is inputted to the next stage of the decoding circuit 14 , The decoding circuit 14 includes, for example, AND gates 20a to 20n (n = 1 in this embodiment).
5). The reason for n = 15 is that
This is because “15” from “1” to “F” is used and “0” is not used.

The pulse width setting circuit 15 is composed of the monomultivibrators 21a to 21n (n = 15 in this embodiment).
These are provided with a pulse width adjusting means 22 made of, for example, a volume as represented by a monomultivibrator 21a. The same applies to the other mono-multi vibrators 21b to 21n. Therefore, it is possible to independently set the pulse widths of a first pulse to an n-th pulse described later.

Here, when the content of the counter 12 is "0", A = B = C = D = 0, A bar = B bar = C bar = D
Since bar = 1, there is no combination in which all of the inputs of the decoding circuit 14 are "1", so that the output side of the decoding circuit 14 remains "0" and no signal appears. On the other hand, when the content of the counter 12 is "1", since A = B bar = C bar = D bar = 1 and A = B = C = D = 0,
Appropriately delayed (for example, 50 ns) pulsed clock appears only on the output side of AND gate 20a having an input combination of B bar, C bar, and D bar.
Trigger a. When the content of the counter 12 is "2", B = A bar = C bar = D bar = 1, B bar = A = C
= D = 0, so that a pulsed clock appears only at the AND gate 20b, triggering the monomultivibrator 21b. Hereinafter, as not shown, the contents of the counter 12 become "3, 4, 5... 15", but the mono-multivibrators 21c, 21d. That is, the mono-multi vibrators 21a to 21n generate a first pulse, a second pulse,..., An n-th pulse (n = 15) to be generated by the start control signal A. The width of the start control signal A is 2τ as in the example shown in FIG. 4, and if this is not changed, only two AND gates and two mono multivibrators are required.

The outputs of the mono-multivibrators 21a to 21n are combined by an OR gate 16 as a collective circuit, and the first pulse, the second pulse..., And the n-th pulse are output as start pulses which appear sequentially on the time axis. . The intermediate pulse and the end pulse are generated and output in exactly the same manner as the start pulse. Further, the start part pulse, the middle part pulse, and the end part pulse are synthesized by an unillustrated assembling circuit (similar to the assembling circuit of FIG. 4), and are applied to the laser diode 5 as a pulse output shown at the lowermost end of FIG. You.

Next, in describing the control signal generation circuit and the pulse train control circuit, first, the basic operation of the control signal generation circuit will be described with reference to the timing chart shown in FIG.

The input CD signal D ₀ passes through the first delay circuit 1 to become the first delay circuit D ₁ , and the signal D ₁ further passes through the second delay circuit 2 to form a second delay signal D ₂ . Become. In this embodiment, the first delay time is described as τ and the second delay time is described as 2τ for the sake of convenience. However, this is not essential, and the minimum space length (CD signal In the case of, it is sufficient that it is 3τ) or less.
A decimal number such as 1.5τ or 0.25τ may be used.

The signals D ₀ , D ₁ , and D ₂ entered into the control signal generation circuit 3 are subjected to logical operation, and A = D ₁ · (D
₁ bar / D ₂ bar), B = (D ₀ · D ₁ ) · (D ₁ · D
₂ ) and C = (D ₁ · D ₂ ) · B bar.

Here, “•” represents logical product and “bar” represents negation. The control signal A is a start control signal, B is an intermediate control signal, and C is an end control signal. The timing of each of the control signals A, B, and C with respect to the input CD signal D ₀ is shown in FIG.
(2τ in the example of FIG. 3), and the pulse width of the ending control signal C is equal to the delay time of the first delay circuit 1 (FIG. 3).
In the example, the pulse width of the intermediate control signal B is equal to the pulse width of the input CD signal minus the delay time of the first and second delay circuits 1 and 2. This is a natural consequence of the logical operation forming the control signals A, B, C. Therefore, when changing the pulse width of the start part control signal A and / or the pulse width of the end part control signal C, the delay time of the second delay circuit 2 and / or the delay time of the first delay circuit 1 are changed. You can change it.

Each of the control signals A, B, and C enters the pulsing circuit 4 and is converted into a pulse having a number corresponding to the pulse width of each of the control signals A, B, and C and having an appropriate pulse width. Is driven to irradiate the optical disk medium 8 to perform long-hole recording.

Next, the operation of the pulse train control circuit will be described with reference to FIGS. First, the pulse train control circuit generates a reference signal for reducing the mark length (finally, the length of the pulse train) when the space length is shorter than the signal length. The reference signal is generated by forming a pulse train control circuit 42 including a monomultivibrator 43 having a clear terminal, delay circuits 44 and 45, inverters 46 and 47, an AND gate 48, and a NAND gate 49, as shown in FIG. chart 6, resets at the fall of the input CD signal, and a circuit for setting the falling of delayed by D ₁ signal τ from D ₀ signal, is generated therefrom reference signals E. Reference numeral 50 denotes a pulse width adjusting means of the monomultivibrator 43 made of volume, which adjusts the reference signal length to, for example, 7τ.

FIG. 7 shows marks 3τ, spaces 3τ, and marks.
Take the CD signal of 3τ, space 7τ, mark 5τ as an example.
FIG. (A) is input C
D signal D₀, (A) shows the first delay signal D₁, (U) is the second
Delay signal D_Two, (D) is the third delay signal D_Three, (E) is D
₀・ D₁, (F) is D₁・ D_Two, (G) is D₁・ D_Three,
(G) shows the intermediate part control signal B (B = (D₀・ D₁) ・ (D
₁・ D_Two)) And (q) indicate the signal A (A = D₁・ (D₁・ D
_Two) Bar) and (co) indicate the end control signal C (C = (D₁・
D_Two) And B bar) and (B) are start part auxiliary signals D (D = D
₁・ (D₁・ D _Three) Bar), (S) are reset signals,
(S) is a set signal, (S) is a reference signal E (E = 7)
τ), (so) is a signal F (F = DE), (ta) is a signal
A '(A' = AF bar), (h) is a pulsed clock
T (T = τ), (ツ) is a pulse output.

In FIG. 7, the reference signal E originally has a length of 7τ, but if a reset signal comes before this (5τ in the example of FIG. 7), it becomes “L”, and again with the set signal after τ. It is set to “H” and becomes “L” after 7τ. The timing at which the reference signal E is set is the first delay output D
Because they coincide with the falling edge of the _1, Come to a reference timing of D _1, the space length immediately before if E is "H" at the beginning portion of the mark is shorter than 7Tau, if E is "L" 7τ It can be determined that this is the case.

When the space length is shorter than 7τ, the start part auxiliary signal D is used to shorten the mark length and control the pulse train. Signal D (in the example of FIG. 7 tau) first delay signal D ₁ only length to shorten the mark length using a third delay signal D ₃ which delays, D = D ₁ · (D ₁ bar · D _Three
Bar). Next, from the reference signal E, D · E =
F (mark length control signal), and A / F bar =
A 'is made to be the start control signal. A 'has a start position delayed by τ when the immediately preceding space length is shorter than the reference signal, and has the same start position as A when the preceding space length is longer than the reference signal length. Since the end position is exactly the same as A, the write mark length can be controlled according to the length of the immediately preceding space length. A, B, and A described in the section of the basic operation of the control signal generation circuit.
By inputting A ′, B, and C as the respective control signals to the pulsing circuit 4 instead of the respective control signals of C, the pulsating output having a pulse train having a length corresponding to the immediately preceding space length (lower end of FIG. 7) ) Is obtained.

As described above, in this embodiment, the write signal of the recording bit is divided into three parts, each of the three parts is pulsed, and the pulse width of each pulsed pulse can be set independently. Therefore, it is possible to irradiate the medium with a laser beam under optimum conditions for each of the three portions. Furthermore, since the space length immediately before the write signal can be determined and the length of the output pulse train can be controlled according to the space length,
It is possible to effectively correct the influence of residual heat from the immediately preceding write bit, to maintain a correct recording bit shape even when performing high-density writing, and to obtain a reproduced signal with a good C / N ratio. Can be.

In the above description, the counter of the pulse conversion circuit is a binary 4-digit counter. However, the present invention is not limited to this, and the number of digits can be increased and more pulse width setting circuits can be added. It goes without saying that you can do it. Also,
Needless to say, the pulse width may be determined by digital means such as a counter instead of the mono-multivibrator for generating the first to n-th pulses.

Further, an analog mono-multivibrator is used for generating the reference signal of the pulse train control circuit.
Of course, it may be realized by digital means such as a counter. In the above description, an example in which only one reference signal is used is shown for convenience. However, a plurality of reference signals are used, and a plurality of
Mark length-τ-4τ, Mark length-5τ-7τ-
Needless to say, finer control such as the mark length as it is may be performed at 0.5τ and 8τ to 11τ.

[Second Embodiment] FIG. 8 is a diagram showing a second embodiment of the present invention.
Is (（) · τ. That is, as shown in a timing chart of the operation in FIG. 8, in this embodiment, the resolution of the pulsing is twice that of the first embodiment, so that a finer pulse width can be set. in this case,
If the pulse width condition of the pulse at the start portion is desired to be the same as that of the first embodiment, the pulse width setting of the monomultivibrators 21a and 21c is set the same as in the first embodiment, and the monomultivibrator 21b and the monomultivibrator 21b are set. The pulse width of the vibrator 21d may be set to a small pulse width so that the trailing edge of the pulse does not exceed the trailing edge of the pulse set by the monomultivibrator 21a or the monomultivibrator 21c.

In the pulsing circuit 4 shown in FIG. 3, the monomultivibrators 21a, the monomultivibrators 21b,.
... The outputs of the mono-multivibrators 21n are logically combined by the OR gate 16, which is a collective circuit, so that even if two pulses are generated simultaneously, no failure or the like occurs. Alternatively, the mono-multi vibrators 21a and 21c may be set to (1/2) · τ, and the remaining pulse widths may be set by the mono-multi vibrators 21b and 21d.
This is exactly the same for the end part. Also,
Set the cycle of the pulsed clock to (1/3) .tau., (1/4)
Needless to say, the resolution may be increased by making the resolution finer than τ.

[Third Embodiment] FIGS. 9 to 11 show a third embodiment of the present invention. In this embodiment, a plurality of pulsating circuits (pulsing means) 31 are provided as shown in FIG. Output (Ch1 and Ch2 channels) of the first and second
Are output to the optical output generation circuits 32 and 33, respectively, and are supplied to the laser diode 34. The first pulse, the second pulse... It is characterized in that pulse inhibiting means 35 for independently inhibiting each other is provided.

The pulse prohibiting means 35 is composed of a switch group such as a snap switch, and is specifically shown as shown in FIG. That is, the pulse inhibit means 35a is provided at the next stage of the AND gates 20a... 20n as the decode circuit 14, and the mono multivibrators 36a to 36n are provided.
36n ( first to n-th pulse generation means) , and are further integrated by a collective circuit 37a to generate a channel 1 of pulse output. Similarly, the other pulse prohibiting means 35b is provided to provide the mono multivibrator 38a.
To 38n (first to n-th pulse generation means) , and are further integrated by a collective circuit 39 to generate a channel 2 of pulse output.

FIG. 11 shows the timing of the third embodiment and the light output of the laser diode 34. The mark length is 5τ, the width of the start control signal A is 2τ, the width of the end control signal C is τ, and the pulsing is performed. The case where the clock T = (１ ／) · τ is shown as an example.

In this embodiment, since T = (1/2) .τ, there are four start portions, two end portions, and a maximum of one intermediate portion.
The six pulse prohibiting means 35 become effective. When the pulse prohibiting means 35a and 35b for channels 1 and 2 are set as indicated by × in FIG. 7B, the pulse output of each channel is as shown in FIG. Since the outputs of channel 1 and channel 2 are connected to the first optical output generation circuit 32 and the second optical output generation circuit 33, respectively, the optical output of the laser diode 34 is shown in FIG.
As shown in (1), the first two pulses have a light output of a second magnitude larger than usual, and the other pulses have light outputs of a normal first magnitude.

As described above, by providing the pulsing circuit 31 with a plurality of channels and having the pulse inhibiting means 35 for independently inhibiting the generation of each pulse, not only the pulse width but also the light Since the output can also be changed, more optimal writing conditions can be determined more finely.

Although the number of channels is set to 2 in this embodiment, the number of channels may be set to 3 or more to change the light output more finely. Further, the pulse prohibiting means does not necessarily need to have a switch, and it goes without saying that means for deleting the pulse generating means at the position or disconnecting the connection may be used.

Fourth Embodiment FIGS. 12 and 13 show a fourth embodiment of the present invention.
In this embodiment, as a means for correcting the influence of the residual heat coming from the immediately preceding write bit described in the above section "Analysis of Problems of the Related Art", the light output of the write start pulse in accordance with the immediately preceding space length is used. Is controlled. Note that this embodiment is described in the claims.
This corresponds to the inventions described in 1 to 5. As the control signal, the mark length control signal F shown in the first embodiment is used. That is, as shown in FIG. 12, an optical output control circuit 51 for inputting a mark length control signal F is provided in a part of the configuration of FIG. 9 shown as the configuration of the third embodiment, and a second optical output generation circuit is provided. 33. Then, as shown in the timing chart of FIG. 13, the light output control circuit 51 changes the amplitude of the write start portion pulse in accordance with the immediately preceding space length based on the mark length control signal F, so that the light output is finely controlled. Is done. Therefore, the method of the present embodiment can also effectively correct the effect of the residual heat.

In the above description, the reference signal E is set to 1 for convenience.
Although only one mark signal and only one mark length control signal F are shown, a plurality of reference signals E ₁ to E ₁ to.
Creating a plurality of mark length control signals F ₁ to F _n from E _n,
It goes without saying that the optical output control circuit may be configured to output an optical output of a magnitude corresponding to each mark length control signal, and to perform finer control.

[Fifth Embodiment] FIG. 14 is a diagram showing the result of correcting the effect of residual heat by the first and second embodiments of the present invention.
15 to 17 show a fifth embodiment of the present invention.

In the first embodiment, the mark writing start position is controlled by increasing or decreasing the number of generated pulses in accordance with the length of the immediately preceding space in order to correct the effect of the residual heat from the previously written bit. are doing. FIG. 14 shows the second embodiment according to the first embodiment.
When the embodiment is applied, that is, under the write pulse condition where the pulsed clock is (1/2) τ and each pulse width of the above-mentioned preferred write pulse condition (pulsed clock τ) is approximately half. in, correction of the remaining heat 0.5Tau (delay time of the third delay signal D ₃ 0.5τ), residual heat when the reference signal length 6Tau (space length immediately before only takes correction of the remaining heat when 3Tau～5tau) was It shows the state of correction.
In the figure, ○ indicates no preheating correction, and Δ indicates the case where preheating correction was performed under the above conditions. The space length immediately before is 3τ ~
At 5τ, the write mark length was shortened by about 0.5τ, so that it falls within ± 0.5τ, which is the criterion for determining the read signal, and the effect of the residual heat correction appears.

However, in this method, the resolution of the write start position is limited by the cycle of the pulse clock. Therefore, if you want to make finer corrections,
For example, if it is desired to change the write start position by 10 ns each time the immediately preceding space length changes by 1τ, a pulsed clock having a period of 10 ns (frequency: 100 MHz) is required, and it is difficult to realize with a generally used TTL. is there. Further, if it is desired to control the write start position in response to every 1τ change of the immediately preceding space length from 3τ to 11τ, nine reference pulses are required, and the amount of hardware increases considerably. .

The fifth embodiment is intended to realize such fine writing start position control with simple hardware. FIG. 15 is a diagram showing the configuration of a part necessary for that. In this figure, the pulse train control circuit of the present embodiment uses the required number of leading pulses (the first pulse of the start part shown in FIG. 3) provided in the required number. Passage path group 54, space recognition means 55 for recognizing the immediately preceding space length, and path selection means 56 for selecting the path of the leading pulse according to the recognition result
It is comprised including. The space recognizing means 55 includes a counter 57 for counting the space length in 1τ units, inverters 58 and 59, a delay circuit 60, a NAND gate 61,
It comprises AND gates 62a to 62n as decoding circuits to which the output signal of the counter 57 is input. The pass path group 54 includes delay lines (DL) 63a to 63n connected in series as a pass path of the leading pulse, and the pass path selecting means 56 receives the outputs of the respective space lengths and the delay lines 63a to 63n. Gates 64a to 64n and OR gate 65 as an integrated circuit
The OR gate 65 generates a trigger signal for the mono-multivibrator 21a shown in FIG.

In the above configuration, as shown in a timing chart of FIG. 16, when an inverted signal D ₁ bar of the first delay signal D ₁ is input to the enable terminal of the counter 57, a space portion is input. D ₁ the bar becomes "H" counter 57 starts counting the clock. End space portion, when the mark portion is input, D ₁ bar goes to "L", the counter 57 is stopped while maintaining the contents of the immediately preceding. That is, when the mark portion starts, the counter 57 functions as a memory for storing information on the immediately preceding space length. Therefore, by decoding the contents of the counter 57, only the output of one decoder corresponding to the immediately preceding space length becomes "H" when the mark portion starts. FIG. 16 shows three decoders (space length 3τ).
) And outputs of 10 decoders (corresponding to a space length of 10τ) are shown as examples. Using this output, the path of the leading pulse is selected. Counter 57 is reset at the rise of the D ₁ bar, and starts counting the next space length.

On the other hand, the leading pulse (starting first pulse) serving as a trigger of the mono-multivibrator 21a shown in FIG. 3 is taken out before that and enters the delay lines 63a to 63n as the leading pulse passage group 54. . The passing path group 54 includes cascaded delay lines 63a to 63n.
(DL ₁₁ , DL ₁₀ ... DL ₃ ), and the subscript added to each of the delay lines 63a to 63n corresponds to the immediately preceding space length. The outputs of the delay lines 63a to 63n are connected to AND gates 62a to 62d as the decode circuits.
AND gates 64a to 64n controlled by the output of
Since 64n is connected, only the pulse that has passed through the path of the delay time corresponding to the immediately preceding space length is extracted and triggers the monomultivibrator 21a (see FIG. 3). In this way, the recognition of the space length immediately before the mark portion and the control of the leading pulse generation position according to the recognition are performed.

The delay lines 63a to 63n
By providing taps in units of, for example, 5 ns,
The top pulse generation position can be controlled with this resolution, and a resolution of 10 ns or less can be achieved with a commonly used TTL.

In the above description, the number of passage selection means 56 is one, and the residual heat is corrected by delaying only the first pulse at the start part.
The residual heat correction can be performed by delaying the n-th pulse.
In this case, only one space recognition means 55 is required. Further, the delay time of each passage selecting means corresponding to each of the first to n-th pulses of the start part is, for example, the delay time of the first pulse when the immediately preceding space length is 3τ is 150 ns, and the delay time of the second pulse is The delay time is 140 ns, the delay time of the n-th pulse is gradually changed to (150-10n) ns, or the delay time of the first pulse is 20 ns when the immediately preceding space length is 10τ. The delay time of the two pulses is 15 ns, the delay time of the n-th pulse is (20-5n) ns
By gradually changing the output pulse train as described above, an output pulse train as shown in FIG. 17 can be obtained, and finer correction of residual heat can be performed.

Sixth Embodiment FIGS. 18 and 19 are views showing a sixth embodiment of the present invention. The control of the head pulse position according to the immediately preceding space length described in the fifth embodiment is suitable for recording at a constant rotational linear velocity typified by a CD (compact disk) among long hole recordings. It cannot be directly applied to recording with a constant rotational angular velocity represented by a magnetic disk. In other words, when recording at a constant rotation angular velocity, the linear velocity becomes higher as it goes to the outer periphery of the disc with a larger rotation radius, and even if a signal of the same length is recorded in time, the recording length on the medium is larger than that of the inner periphery. Long. Therefore, even if the space length immediately before is the same, the distance on the medium is longer in the outer peripheral part than in the inner peripheral part, and the influence of residual heat is small.

Therefore, in the sixth embodiment, the delay time of each of the delay lines 63a to 63n is changed according to the radius of rotation of the disk.

For recording at a constant rotational angular velocity to which the present embodiment is applied, there is provided a means for knowing the current rotational radius position from the position of the optical head or the address recorded in the medium. This means is generally a signal represented by a binary code, for example. Therefore, in this embodiment, as shown in FIG. 19, the radial position signals represented by binary signals are inputted to AND gates 71a to 71n as decoding circuits, and an appropriate number of AND gates as radial position decoders are provided. Only one of the outputs 71a to 71n becomes "H". Outputs S _{1 to} Sn of the AND gates 71 a to 71 _n are, as shown in FIG. 18, n groups of AND gates 72 as radial position selection gates.
A _{1 to} 72A _n , 72B _{1 to} 72B _n ,... 72N ₁ to
72N _n , and the other input terminals of these gates are connected to output taps 1, 2,... N of the delay lines 63a to 63n. Also, each gate 72A
_The outputs of _{1 to} 72A _n ,... 72N _{1 to} 72N _n are grouped into groups and input to OR gates 73a to 73n. The next stage is provided with space recognizing means 55 partly common to the fifth embodiment. ing. Therefore, by setting "H" 1 pieces of the outputs S ₁ to S _n of the radius position selection gates, the output taps of the delay line 63A～63n 1, 2
... N are selected, and only the leading pulse signal that has passed through this output tap is input to the delay line of the next stage, and the leading pulse is output by subsequent logic processing.

The delay time between the input and output taps of each of the delay lines 63a to 63n does not need to be the same for each delay line, but may be set according to the characteristics of the disk medium. The passage selecting means according to the immediately preceding space length is exactly the same as in the fifth embodiment.

In the above description, an example was shown in which the residual heat was corrected only by the first pulse (first pulse at the start). However, as in the fifth embodiment, a plurality of circuits shown in FIGS. It goes without saying that the residual heat correction using the first to n-th pulses may be performed.

[Seventh Embodiment] FIGS. 20 to 27 are views showing a seventh embodiment of the present invention. In the present embodiment, the residual heat correction according to the immediately preceding space length is performed more finely than in the above-described embodiments.

The pulse train control circuit 80 of the present embodiment shown in FIG. 21 comprises a space recognition circuit 81 and a time compression circuit 82.

The space recognition circuit 81 is a circuit similar to the space recognition means 55 shown in FIG. 15, and generates a space length signal corresponding to the immediately preceding space length 3τ to 11τ.

The time compression circuit 82 is a voltage control delay circuit 83
And a delay time control circuit 84. The voltage control delay circuit 83 is a circuit whose delay time changes according to the applied control voltage, and generally includes a VCDL (Voltage) in which a variable capacitance diode and an inductance are combined.
Controlled Variable Delay
Line). In this embodiment, two elements manufactured by JPC are used, and FIG.
As shown in FIG.
A variable range of 0 ns to 700 ns is obtained.

Considering the case where a sawtooth control voltage having a length of 3τ (690 ns) shown in FIG. 23 is applied to the voltage control delay circuit 33, the delay time of the voltage control delay circuit 83 is represented by the progress of the horizontal axis. It changes with time as shown in FIG. Voltage control delay circuit 8 at the timing of elapsed time 0
The pulse input to 3 propagates through the delay circuit 83, and during the propagation, the delay time of the delay circuit 83 changes every moment as shown in FIG. Therefore, the pulse is delayed by the delay time (10
20 ns) and the average value of the delay time in the steady state (700 ns), that is, (1020 + 700) / 2 = 860 ns.
At the output end. In addition, elapsed time 300
The pulse input at the timing of ns is delayed by (880 + 700) / 2 = 790 ns because the delay time of the delay circuit 83 at that timing is 880 ns. As described above, a pulse that is input later than the time when the sawtooth control voltage is applied has a shorter delay time. However, 6
Since the control voltage is no longer applied to the pulse input with a delay of 90 ns or more, the delay time
0 ns.

FIG. 25 shows an example of time compression of a pulse train based on the above principle. The residual heat correction value at the immediately preceding space length 3τ is 160 ns, and the corresponding sawtooth control voltage is 15 V, 690 ns shown in (b).
The input pulse train has a mark length 4τ shown in FIG.
Is preferably applied.

The leading edge of the first pulse is delayed and output after 860 ns. In addition, since the trailing edge of the first pulse is input after 100 ns, it is delayed by (974 + 700) / 2 = 837 ns according to the above principle, and is output at the time of 837 + 100 = 937 ns based on the origin of the elapsed time. Is done. Therefore, the first pulse width of the output pulse train is 937-860 = 77 ns. Similarly, the leading edge of the second pulse is 948 ns, the trailing edge is 1025 ns, and the pulse width is 77 ns as in the first pulse. Similarly, the third pulse has a leading edge of 1036
ns, width 62 ns, the fourth pulse has a leading edge of 1125 ns, width 46 ns, fifth,
The leading edge of the sixth pulse is 1213 ns and 1301 ns, respectively, and the width is 46 ns and 39 ns, respectively. When the seventh pulse is input, the control voltage is in a steady state, so that the seventh and eighth pulses are output with a delay of 700 ns.
In this way, the output pulse train shown in (c) is obtained.
Actually, a pulse train in which various mark lengths and space lengths are combined is input, but the position of the trailing edge of the last pulse is all maintained at a position delayed by 700 ns from the input pulse. That is, while maintaining the relationship between the mark length and the space length of the input signal, only the part of the pulse train corresponding to the sawtooth control voltage width from the beginning of each pulse train is time-compressed for residual heat correction.

In the method of the fifth embodiment shown in FIG.
Even if the residual heat correction is performed by delaying the pulse by 160 ns and delaying the second, third, and fourth pulses by 150 ns, 140 ns, and 130 ns, respectively, only the space portion is compressed, and the pulse width itself does not change. On the other hand, the method of this embodiment is characterized in that not only each space portion but also each pulse width is compressed at the same ratio.

Taking the pulse train shown in FIG. 25A as an example, the total pulse width is 590 ns, and the ratio (pulsation rate) to the pulse train length of 885 ns is about 67.
%. On the other hand, in the method of the fifth embodiment shown in FIG. 17, the total pulse width is the same, and only the length of the pulse train is 885-
Since 160 = 725 ns, the pulse rate is 590/7
25 = 0.81, 81%, which is larger than the input pulse train. On the other hand, in the method of this embodiment, the total pulse width is 487 ns and the pulse rate is 487/725.
= 0.67, about 67%, which is the same as the pulse rate of the input pulse train.

The pulse rate can also be considered as the energy density of the writing laser beam. Keeping the same as the input pulse train, which is a preferable pulse condition, makes the bit shape more accurate even when the residual heat correction is performed. Means that you can write

Further, the range of the residual heat correction can be applied not only to the start pulse but also to the intermediate pulse. That is, in the residual heat correction by time compression of the present embodiment, the input pulse train can be compressed in a similar manner over the entire correction range regardless of the pulse train of any shape and combination in principle. Therefore, the pulse train does not necessarily have to be separated into a start part, an intermediate part, and an end part as in each of the above-described embodiments. For example, each of the mark lengths of 3τ to 11τ is composed of a completely different combination of pulse trains. However, even if it is, the residual heat correction can be performed effectively.

FIG. 26 shows an example of the delay time control circuit 84. The delay time control circuit 84 includes a correction range setting circuit 90 for generating a pulse having a width equal to the control voltage width from the first delay signal D ₁ , a sawtooth wave generating circuit 91 for converting the pulse into a sawtooth wave, and a space recognition circuit. A delay time setting circuit 92 for setting a suitable delay time for residual heat correction according to the results of the means 55 and 81, and a subtraction circuit 93 for converting an output waveform into a waveform based on 15V.

[0118] correction range setting circuit 90 is composed of monostable multivibrator 94, generates a constant width of the pulse that starts with the mark leading edge of the input signal D ₁ as shown in FIG. 27 (a) (see FIG. 27 (b)) I do. Pulse width is volume 94
R can be set, and in this example, the pulse width is 3τ (690 ns).

The pulse is converted by a sawtooth wave generating circuit 91 by a differentiating circuit 95 as shown in FIG. Rf is a feedback resistance of the operational amplifier. By adjusting this, the linearity of the sawtooth wave can be changed.

The delay time setting circuit 92 is composed of nine sets of amplifiers 96 and switch means 97 corresponding to each space length. Since the amplification factor of each amplifier 96 is determined by Rf / R,
By changing the feedback resistances Rf3 to Rf11 of each amplifier 96, the peak value of the output sawtooth wave can be changed, and the output of each amplifier 96 can be set as shown in FIG. Switch means 97 such as an analog switch is connected to the output of each amplifier 96, and the switches are controlled by a space length signal output from the space recognition means 55. Therefore,
On the output side of the switch means 97, only one sawtooth wave having a peak voltage corresponding to the space length (preheat correction value) appears.

The subtraction circuit 93 is a one-time inverting amplifier 98, which comprises an operational amplifier and resistors Re and Rs, and outputs a difference between input terminals. Since the positive input terminal is connected to 15 V, a waveform shown in FIG. 27E obtained by subtracting the sawtooth wave input to the negative input terminal is output. Re is 0 when the switch 97 is all off.
V. The output of the subtraction circuit is applied as a sawtooth control voltage to the voltage control delay circuit, and the above-described time compression is performed.

The operational amplifier used in each of the above circuits is 15 V
A high-speed, high-slew-rate device capable of obtaining the above output voltage is desirable. For example, LH0032CG or the like is preferably used.

In the above example, the correction range setting circuit 90
And a sawtooth wave generating circuit 91 with a monomultivibrator 94
The present invention is not limited to this. For example, the two circuits are integrated using a sawtooth wave generated on the base side of a monomultivibrator having an asymmetrical time constant. Needless to say, it may be formed.

FIG. 20 shows an example of a preferable result of the residual heat correction according to the present embodiment. In the figure, ○ indicates data without correction, and △ indicates data with correction. The write pulse train has the preferable pulse conditions shown in FIG. 25A, the correction value (maximum correction) immediately before the space length 3τ is 160 ns, the correction value when the space length 4τ is 100 ns, and 60 ns, 30 ns in sequence. 20 ns, and 10 ns for all spaces longer than 8τ. Despite some non-linearity, almost perfect residual heat correction has been performed.

Eighth Embodiment FIGS. 28 and 29 show an eighth embodiment. In the seventh embodiment, the range of the residual heat correction (the width of the sawtooth wave control voltage) has been described as 3τ. This is because the minimum mark length of the CD signal is 3τ and the correction range is, for example, 5τ.
This is because a problem occurs that the last pulse position of the pulse train in the case of the mark length 3τ is greatly delayed from the specified position. On the other hand, on the other hand, there is also a demand for performing a wider range correction of, for example, 5τ or more for a pulse train having a long mark length of 7τ or more to make the pulse train more similar to the input pulse train. In the present embodiment, the final pulse of the pulse train having a short mark length is brought to a specified position even when a wider range of correction is performed.

FIG. 28 shows a delay time control circuit according to this embodiment. This delay time control circuit is partly different from the circuit of FIG. 26. A switch 102 for selectively connecting the negative input side of the subtraction circuit 101 to zero potential, and a switch control circuit 103 for controlling the open / close timing of the switch 102 And an inverter 104 for inverting the first delay signal and inputting the inverted signal to the switch control circuit 103. A switch control signal such as a first delay signal D ₁ bar is input to the switch control circuit 103. D ₁ bar Low during the mark, since the High during space, do it this controls the switch adjusted to a suitable timing in the switch control circuit 103, just before the end of the mark negative input side of the voltage of the subtraction circuit 101 Can always be set to 0V.

Considering the case where a pulse width of 4τ is set by the correction range setting circuit 90 and a pulse train of mark length 3τ is input to the voltage control delay circuit 83, the subtraction circuit 1
The input waveform 01 is the waveform shown in FIG. 29A, and the output waveform is the waveform shown in FIG. Therefore, when the output waveform of the subtraction circuit 101 is applied to the voltage control delay circuit 83, the delay time of the delay circuit 83 returns to a steady state just before the last pulse of the pulse train having the mark length 3τ is input. Therefore, the timing at which the last pulse is output is the position of the input time +700 ns, similarly to the last pulse of the pulse train of another mark length.

Incidentally, for a pulse train having a mark length longer than the pulse width set by the correction range setting circuit 90,
Since the switch 102 is off until the control signal having the set pulse width becomes a steady state, there is no effect.

[0129]

According to the method of the present invention, even when high-density writing is performed, the effect of the residual heat from the adjacent writing position is effectively corrected, and the accurate recording bit shape, that is, the writing start is started. It is possible to write a recording bit having a predetermined position and a predetermined shape, and it is possible to obtain a high-quality reproduction signal having a good C / N ratio.

Further, according to the device configuration of the present invention, the effect of the above-mentioned residual heat can be effectively corrected and the above-mentioned recording bit shape can be written by simply adding simple hardware, and the same effect is obtained. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a write pulse condition and a write bit shape suitable for explaining the principle of the present invention.

FIG. 2 is an overall configuration diagram of a first embodiment.

FIG. 3 is a block diagram of a pulse generating circuit according to the first embodiment.

FIG. 4 is a timing chart showing a basic operation of the first embodiment.

FIG. 5 is a circuit diagram of a reference signal generation circuit according to the first embodiment.

FIG. 6 is a timing chart of the reference signal generation circuit of the first embodiment.

FIG. 7 is a timing chart of the pulse train control circuit of the first embodiment.

FIG. 8 is a timing chart of the second embodiment.

FIG. 9 is a diagram illustrating an output system of a pulse generation circuit according to a third embodiment.

FIG. 10 is a detailed circuit diagram of a pulse prohibiting unit according to a third embodiment.

FIG. 11 is a timing chart of the third embodiment.

FIG. 12 is a diagram illustrating an output system of a pulsed output signal according to a fourth embodiment.

FIG. 13 is a timing chart of light output control according to the fourth embodiment.

FIG. 14 is a diagram showing a result of correcting the influence of residual heat by the first and second embodiments.

FIG. 15 is a block diagram illustrating a configuration of a main part of a pulse train control circuit according to a fifth embodiment.

FIG. 16 is a timing chart of the fifth embodiment.

FIG. 17 is a diagram showing pulse outputs by a plurality of passage selecting means of the fifth embodiment.

FIG. 18 is a diagram showing a circuit for generating a leading pulse according to a sixth embodiment.

FIG. 19 is a diagram showing a circuit for selecting a radial position according to the sixth embodiment.

FIG. 20 is a diagram showing an example of the residual heat correction of the seventh embodiment.

FIG. 21 is a diagram illustrating a configuration of a pulse train control circuit according to a seventh embodiment.

FIG. 22 is a diagram illustrating characteristics of the voltage control delay circuit according to the seventh embodiment.

FIG. 23 is a diagram illustrating a sawtooth control voltage and a delay time according to a seventh embodiment.

FIG. 24 is a diagram illustrating characteristics of the voltage control delay circuit according to the seventh embodiment.

FIG. 25 is a diagram showing an output pulse train obtained by performing a residual heat correction by time compression according to the seventh embodiment.

FIG. 26 is a circuit diagram of a delay time control circuit according to a seventh embodiment.

FIG. 27 is a diagram showing operation waveforms of each unit of the delay time control circuit according to the seventh embodiment.

FIG. 28 is a diagram showing a delay time control circuit for performing a wider range of residual heat correction of the eighth embodiment.

FIG. 29 is a diagram showing operation waveforms of each part of the delay time control circuit according to the eighth embodiment.

FIG. 30 is a diagram illustrating an example of a CD signal.

FIG. 31 is a diagram showing the shape of a recording bit according to a conventional method.

FIG. 32 is a diagram showing a change in a write mark length depending on the immediately preceding space length.

[Explanation of symbols]

 1: first delay circuit (first delay means) 2: second delay circuit (second delay means) 3: control signal generation circuit (control signal generation means) 4, 31: pulse generation circuit (pulse generation) Means: 5: laser diode 8: optical disk medium 9: laser irradiation means 10, 80: pulse train control circuit (pulse train control means) 32: first light output generation circuit 33: second light output generation circuit 35: pulse prohibition means 51: Optical output control circuit 54: Passage path group 55: Space recognition means 56: Passage path selection means 81: Space recognition circuit (space recognition means) 82: Time compression circuit (time compression means) 83: Voltage control delay control circuit 84 : Delay control circuit 90: correction range setting circuit 91: sawtooth wave generating circuit 92: delay time setting circuit 93101: subtraction circuit 94: mono-multivibrator 95: differentiation circuit 96: amplifier 97: switch means 102: switch 103: switch control circuit

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Nakata 4-1-1, Kamidadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-63-302424 (JP, A) JP-A-62-8371 (JP, A) JP-A-63-266633 (JP, A) JP-A-63-39138 (JP, A) JP-A-59-24452 (JP, A) JP-A-63-48617 (JP) , A) (58) Surveyed fields (Int. Cl. ⁷ , DB name) G11B ^7/ 00-7/013 G11B 7/125

Claims (6)

(57) [Claims] 1. An information writing control method for writing an information signal composed of a mark signal section and a space signal section on an optical disc on which information is recorded in which the length of a recording bit carries information, wherein the mark signal section has The corresponding information signal is sent to the first to n-th
(N (integer) ≧ 2) a series of pulsed pulses
And the first pulse generating means includes a first pulse train at the beginning of the series of pulse trains.
It can be generated by changing the amplitude of the pulse.
Space signal immediately before the information signal corresponding to the
The length of the information signal corresponding to the first part is the first space length.
Generating a first pulse having a first amplitude, if any,
If the second space length is shorter than the first space length,
A first pulse having an amplitude of 2 is generated, and second to n-th pulse generating means generate a second pulse of the series of pulse trains.
To the n-th pulse, each of which corresponds to the space length generated by the first pulse generating means.
A first pulse having a corresponding amplitude and the second to n-th pulses
A series of the second to n-th pulses generated by the generating means.
By configuring a pulse train, the pulse train
The pulse train is controlled to be applied to the light irradiation means.
Mark that can obtain a reproduced signal with a good C / N ratio
An optical disk information writing control method, wherein writing of a signal portion is performed . To 2. A disc length of the recording bit recording information carrying information, in the information write control method for writing information signal composed of mark signal parts and space signal parts, the mark signal part The corresponding information signal: a) quickly raise the temperature of the medium to a writable temperature;
And that the start section, b) and holds the heat radiation balance temperature elevated medium
Intermediate portion and, c) a laser beam irradiation own the temperature drop that occurs along with the finished
And an end section for keeping the constant condition, and an information signal corresponding to the mark signal section is transmitted to each pulse.
In order for the loose width to be a suitable condition,
By pulsing each part,
A first signal corresponding to the length of the information signal corresponding to the mark signal portion
To n-th (n (integer) ≧ 2) pulses
A series of pulse trains, corresponding to the mark signal section.
When the length of the information signal changes corresponding to the information,
Change the number of pulses in the middle part of the pulse train.
And a first pulse generating means for outputting the first pulse of the series of pulse trains.
It can be generated by changing the amplitude of the pulse.
Space signal immediately before the information signal corresponding to the
The length of the information signal corresponding to the first part is the first space length.
Generating a first pulse having a first amplitude, if any,
If the second space length is shorter than the first space length,
A first pulse having an amplitude of 2. The second to n-th pulse generating means generate
To the n-th pulse, each of which corresponds to the space length generated by the first pulse generating means.
A first pulse having a corresponding amplitude and the second to n-th pulses
A series of the second to n-th pulses generated by the generating means.
By configuring a pulse train, the pulse train
Controls the serial series of pulses, to apply a series of pulses which are the controlled laser irradiation means
This makes it possible to obtain a reproduction signal with a good C / N ratio.
A write signal section for writing the optical disk information. 3. A laser irradiation means for an optical disk medium.
Information that the length of the recording bit carries information by irradiating the laser
Mark signal section and space signal on the optical disc for recording
Disc information for writing an information signal composed of a section
In the writing control device, a space immediately before an information signal corresponding to the mark signal section is provided.
Space recognizing means for recognizing the length of the source signal portion, a start control signal, an intermediate control signal and an end control signal.
And generated by the space recognition unit.
Control signal generation that generates control signals corresponding to the space length
Means and information corresponding to the mark signal portion based on the control signals.
The media signal to the writable temperature quickly.
Start to raise the temperature of the raised medium
And the intermediate part to hold the
End part that keeps the temperature drop that occurs due to the specified conditions
And pulsing each of the three parts to
A first signal corresponding to the length of the information signal corresponding to the mark signal portion
To n-th (n (integer) ≧ 2) pulses
And a series of pulsing means for generating a pulse train with said pulsing means, variable setting the amplitude of the first pulse of the beginning of the series of pulses
Can be generated further, and based on the control signal,
If the source length is the first space length, it has the first amplitude
Generating a first pulse shorter than the first space length.
If the second space length is longer than the first space having the second amplitude,
First pulse generating means for generating a pulse, and generating second to n-th pulses of the series of pulse trains, respectively.
Second to n-th pulse generating means, and first to n-th pulse generated by the first to n-th pulse generating means.
And a pulse output means for outputting a pulse. The pulse output means outputs a pulse according to the space length generated by the first pulse generation means.
A first pulse having a corresponding amplitude and the second to n-th pulses
A series of the second to n-th pulses generated by the generating means.
By configuring a pulse train, the pulse train
Controls the serial series of pulses, to apply a series of pulses which are the controlled laser irradiation means
This makes it possible to obtain a reproduction signal with a good C / N ratio.
An optical disk information writing control device , wherein a write signal portion is written . 4. An information recording in which the length of a recording bit carries information.
A mark signal section and a space signal section
Information writing control device for writing the generated information signal
In this case, a stripe immediately before an information signal corresponding to the mark signal portion is provided.
A space for recognizing the length of the information signal corresponding to the pace signal section
Source recognition means and a length corresponding to the length of the information signal corresponding to the mark signal portion.
To the first to n-th (n (integer) ≥ 2) pulses
Pulsing means for generating a series of pulsed pulse trains.
Wherein said pulsing means, variable setting the amplitude of the first pulse of the beginning of the series of pulses
And the space length may be changed to the first space.
The first pulse having the first amplitude
With a second space length shorter than the first space length.
A first pulse for generating a first pulse having a second amplitude, if any;
Pulse generating means for generating each of the second to n-th pulses of the series of pulse trains
Second to n-th pulse generating means, and first to n-th pulse generated by the first to n-th pulse generating means.
And a pulse output means for outputting a pulse. The pulse output means outputs a pulse according to the space length generated by the first pulse generation means.
A first pulse having a corresponding amplitude and the second to n-th pulses
A series of the second to n-th pulses generated by the generating means.
By configuring a pulse train, the pulse train
Controls the serial series of pulses, to apply a series of pulses which are the controlled laser irradiation means
This makes it possible to obtain a reproduction signal with a good C / N ratio.
An optical disk information writing control device , wherein a write signal portion is written . 5. The method according to claim 1, wherein each pulse constituting the series of pulses is
Each amplitude can be set independently according to the space length
The optical disk according to claim 1 or 2,
Disk information writing control method. 6. The method according to claim 1, wherein each of the pulses constituting the series of pulse trains
Each amplitude can be set independently according to the space length
5. The method according to claim 3, wherein
Optical disk information writing control device.