JP2000222731A - Recorder and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To finely control laser power for a high density recording. SOLUTION: In the recorder, plural mark forming levels, plural preheat levels, and an off level are made to be switched as drive pulse levels. By switching the levels for every unit pulse interval, drive pulses having an arbitrary pulse waveform are generated and supplied to a laser means. The drive pulses are generated to form a mark and a space based on recording data. In particular, for the drive pulses in the interval which forms a space, drive pulses having a pulse waveforms that are set in accordance with a space length, are generated. In other words, for the level of preheat, the levels are switched in plural steps (a PreH3T, a PreHMid, and a PreHEnd) so that the laser power is finely controlled even in a space interval.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a recording medium,
The present invention relates to a recording apparatus and a recording method for performing data recording (optical modulation recording) using laser light modulated by recording data.

[0002]

2. Description of the Related Art When performing optical modulation recording on a recording medium such as an optical disk, a laser is pulsed to perform thermal control for excellent shaping of marks (pits) formed on the disk. Light emission is performed. Specifically, a pulse waveform is set as a drive pulse for driving the laser, and the level (peak value) of each pulse period is also controlled to control the laser power and the laser irradiation period.

For example, FIG. 15 shows an example of a laser emission pattern (drive pulse waveform). The data sequence recorded on the disc includes marks of various lengths and spaces between the marks. The length of the mark and the length of the space depend on the modulation method of the recording data. For example, when the recording data is a run length limited code RLL (1, 7).
And the mark length is pre-coded as mark edge recording, the mark length is 2T at minimum and 8T at maximum.
Becomes FIG. 15 shows a data string portion in which a 5T mark, a 4T space, and a 2T mark are continuous (a vertical dashed line in the drawing is separated by 0.5T), but a drive for forming such a data string is shown. The pulse waveform is shown below.

[0004] For example, the level (peak value) of a drive pulse
As shown, “end”, “main”, “t”
hd, “sub”, and “pre” are prepared to be switchable. Although “cool” is a so-called off level, it is a state in which laser emission is performed with a very small laser power as a bias current level for the laser diode. Here, four levels “end”, “main”, “thd”, and “sub” are levels used for forming a mark.
On the other hand, the level "pre" does not directly contribute to mark formation, but is a level for applying preheating to the recording surface. The level “cool” is a level that contributes to cooling of the recording surface.

In the drive pulse waveform of this example, the level is “sub” during the first 1T period of the mark, and the level is “thd” during the subsequent 0.5T period. Then, 0.
As a pulse via level "pre" every 5T period,
The pulse is at the level "main", and the last pulse of the mark is at the level "end". Therefore, as shown in the figure, in the case of the 2T mark, a waveform in which the level “sub”, the level “thd”, and the level “pre” are combined in the 2T period, and in the case of the 5T mark, the first 2T period is the 2T mark. However, after the pulse of the level “main” is generated twice, the last pulse becomes the level “end”. 3T, 4 not shown
For each of the marks T, 6T to 8T, a pulse waveform is generated according to the same rule. For example, in the case of the 3T mark, the next pulse after the first 2T period is the last pulse, so that the waveform has a drive pulse similar to the 2T mark and a pulse of level “end” added. Further, in the 6T mark, after the same drive pulse as the 2T mark, three levels “mai”
n ”, and finally the level“ en ”
The waveform has the pulse “d” added.

On the other hand, in the space forming period, the entire period may be set to the level "cool". However, in practice, it is preferable to give a certain amount of preheating, and therefore, as shown in the drawing. During the space forming period, the laser is driven by a drive pulse of level "pre".

[0007]

For example, by finely controlling the level of the drive pulse (that is, the laser power) as described above, it has been possible to form a recording mark on a disk well. However, as the high-density recording on the recording medium is promoted as in recent years, and the mark period and the space period are physically reduced, even if the drive pulse is controlled as described above, the situation becomes insufficient. Was.

As the high-density recording advances, not only the fine control during the mark period, but also the preheating method during the space period affects the shaping of the record mark row.

Further, it is expected that the recording density will further increase in the future, and that the structure and material characteristics of the recording medium itself will change in response to this. In consideration of recording compatibility and recording compatibility, it is important not only to enable simple and fine laser emission control, but also to allow the control method to be flexibly changed.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in response to these circumstances, and it is an object of the present invention to realize laser power control capable of coping with further high-density recording in the future.

According to the present invention, a plurality of mark forming levels, a plurality of preheat levels, and an off level can be switched as the level of the drive pulse, and the level can be switched at every unit pulse period. A drive pulse generating means for generating a drive pulse having a pulse waveform and supplying the drive pulse to the laser means is provided. Further, a drive pulse for forming a mark and a space based on the recording data is generated by the drive pulse generating means, and a drive pulse in a section where a space is formed is a pulse waveform set according to the space length. And pulse waveform control means for generating the drive pulse.

The pulse waveform set according to the space length is a pulse waveform that can be realized by selecting a certain level from a plurality of preheat levels and off levels for each unit pulse period. To be.

The setting of the pulse waveform according to the space length is stored in the register section. By updating the setting data in the register section, the setting of the pulse waveform according to the space length is changed.

That is, in the present invention, the level for preheating (preheating) can be switched to a plurality of levels. As a drive pulse in a section where a space is formed, a drive pulse having a pulse waveform set according to the space length is output, and fine laser power control according to the space length is enabled. Further, the pulse waveform set according to the space length means that a certain level is selected from a plurality of preheat levels and off levels for each unit pulse period, so that the laser level output during the space period is also fine. Be able to control. The setting of the pulse waveform in the space period can be changed by register data, so that the optimum setting can be flexibly realized according to various conditions such as the recording density and the type of recording medium.

[0015]

Embodiments of the present invention will be described below in the following order. 1. 1. Configuration of recording device 2. Example of drive pulse level setting 3. Example of drive pulse for mark formation Drive pulse example for space formation

1. Configuration of Recording Apparatus The configuration and operation of the recording / reproducing apparatus as an embodiment of the recording apparatus of the present invention will be described. FIG. 1 is a block diagram of the recording / reproducing apparatus of the present embodiment. Note that the block diagram of FIG. 7 mainly shows a processing system for a recording / reproducing signal, and there are some other parts omitted from the servo system.

The magneto-optical disk 6 as a recording medium is rotated, driven by a spindle motor 9 in a recording / reproducing apparatus, and information is recorded, reproduced, and erased by the operation of an optical pickup 7 and a magnetic head 5. Optical pickup 7 and magnetic head 5 for recording, reproducing, and erasing
The position control (seek, tracking servo, and thread servo), the focus servo of the laser beam from the optical pickup 7, and the rotation servo of the spindle motor 9 are performed by a servo system (not shown).

A drive controller (hereinafter, referred to as a controller) 2 serves as a master controller of the recording / reproducing apparatus, and controls various operations and communicates with the host computer 1. That is, the controller 2 controls the operation of recording the supplied data on the disk 6 in response to the recording instruction from the host computer 1, and also reads the requested data from the disk 6 in response to the instruction from the host computer 1. Control of the transfer to the host computer 1.
The controller 2 also has a function of encoding and decoding data.

The CPU 3 is a part for controlling each part for a recording / reproducing operation based on an instruction from the controller 2. For example, it performs various controls on the RF block 20 of the reproduction system, and gives instructions to the DSP 15 functioning as a servo processor.

At the time of recording, the controller 2 receives user data to be recorded in accordance with a command from the host computer 1 and performs encoding based on the user data as information words, for example, RLL (1, 7) as code words.
Generate a sign. This codeword is supplied as recording data WDATA to a laser power control unit (hereinafter, referred to as LPC) 4. Controller 2 is WGAT
As the E signal, the light emitting operation in the recording mode and its timing are instructed to the LPC 4. Further, a recording clock WCLK which is a reference for the recording processing operation is generated and supplied to the LPC 4.

The LPC 4 generates a laser drive signal (drive pulse) so that the laser output from the optical pickup 7 is executed at the time of reproduction, recording, and erasing. This drive pulse is APC (Auto Power C
and a drive section (hereinafter referred to as an APC section) 16 which supplies a current corresponding to a drive pulse to the laser diode, whereby a laser output from the laser diode in the optical pickup 7 is performed. .

The laser emission level at the time of reproduction, recording, and erasing, that is, the drive pulse value of the laser, is set in accordance with an instruction from the DSP 15 (CPU 3). As will be described later in detail, the drive pulse waveform (crest value and pulse width) is particularly finely controlled during the recording operation. The drive pulse waveform is set by setting data from the DSP 15 to LPC4.
This is performed by being set in an internal register.

When recording is instructed by the WGATE signal, the LPC 4 responds to the supplied recording data WDATA and recording clock WCLK by the optical pickup 7.
A laser pulse is generated by generating a drive pulse capable of finely controlling the laser power of the laser beam to form a mark row (pit row) having a magnetic polarity on the magneto-optical disk 6, thereby performing recording. At the time of this recording, the magnetic head 5 applies a bias magnetic field to the magneto-optical disk 6.

At the time of reproduction, the controller 2 and C
The following operation is performed by the control of PU3.

The controller 2 receives the RGATE signal, PGA
The TE signal is supplied to the LPC 4 and the RF block 20,
The playback operation is controlled. That is, the controller 2 is RGATE
A signal instructs the LPC 4 to continuously emit light with the laser power as the reproduction level,
0 is instructed to perform a reproduction process. The sector format of the disk 6 includes a header (an area in which addresses and the like are recorded by embossed pits) and a data portion (MO area in which user data and the like are recorded by magneto-optical recording). Of the LPC4.
And the operation of the RF block 20 is performed.

At the time of reproduction, first, the LPC 4
A laser drive pulse is generated according to the E signal, and a laser output for a reproducing operation is executed from the optical pickup 7. The optical pickup 7 irradiates the magneto-optical disk 6 with laser light, and receives reflected light generated thereby. Further, various signals are generated by arithmetic processing of signals according to the amount of reflected light. That is, a sum signal R +, a difference signal R-, a focus error signal (not shown), and a tracking error signal.
Signal. Note that information reading from the data section in the MO area is performed, for example, by MSR (Magnetically induced).
Super Resolution) playback method.

The sum signal R + is supplied to the changeover switch 10 after the gain is adjusted by the amplifier 8a. The difference signal R− is supplied to the changeover switch 10 after the gain is adjusted by the amplifier 8b.
The gain setting in the amplifiers 8a and 8b is determined by the CPU.
3 is performed. Although not shown, the focus error signal and the tracking error signal are supplied to the DSP 15 and used for controlling the servo system by the DSP 15.

The changeover switch 10 performs a changeover operation according to the PGATE signal, and outputs the sum signal R + or the difference signal R−.
Is supplied to the filter unit 11. That is, in the sector format of the magneto-optical disk 6, during a period in which a signal reproduced from a header (address portion) formed by embossing is supplied to the changeover switch 10,
The sum signal R + is supplied to the filter unit 11. Further, during a period in which a signal reproduced by the MSR method from a data portion where magneto-optical recording is performed is supplied to the changeover switch 10, the difference signal R− is supplied to the filter unit 11.

The filter unit 11 includes a low-pass filter for performing noise cut and a waveform equalizer for performing waveform equalization. The input signal is output to the Viterbi decoder 13
Are equalized so as to obtain a partial response characteristic suitable for the Viterbi decoding method performed by. The A / D converter 12 performs A / D conversion on the output of the filter unit 11 in accordance with the reproduction clock DCK, and outputs a reproduction signal value z [k]. The Viterbi decoder 13 generates decoded data DD by a Viterbi decoding method based on the reproduced signal value z [k]. The decoded data DD is a maximum likelihood decoded sequence for the recording data. Therefore, when there is no decoding error, the decoded data DD matches the recording data.

The decoded data DD is supplied to the controller 2. As described above, the recording data is a codeword generated from user data by encoding such as channel encoding. Therefore, if the decoding error rate is sufficiently low, the decoded data DD can be regarded as recording data as a codeword. The controller 2 outputs the decrypted data DD
Then, user data and the like are reproduced by performing a decoding process corresponding to the encoding such as the channel encoding described above.
For example, decoding processing of (1-7) RLL system is performed.

A reproduction clock DCK for such a reproduction process is generated by the PLL unit 14. That is, the output of the filter unit 11 is also supplied to the PLL unit 14, and the PLL unit 1
Reference numeral 4 generates a reproduction clock DCK by a PLL operation on the supplied signal. The reproduction clock DCK is supplied to the controller 2, the A / D converter 12, the Viterbi decoder 13, and the like.
Is performed at a timing according to.

FIG. 2 shows the constructions of the LPC 4 and the APC section 16 in detail. As shown, the LPC 4 includes a digital synchronizing unit 31 and a pulse generator 3.
2, register 33, pulse selector 34, switch 3
5, D / A converters 36-1, 36-2 ... 36-9
Is provided.

Setting data of the pulse waveform is set in the register 33 by the register bus from the DSP 15.
For example, the DSP 15 sets setting data in the register 33 in accordance with an instruction from the controller 2 (CPU 3) so that the drive pulse waveform at the time of recording has a predetermined waveform corresponding to the mark length and the space length. become. In this example, the recording data is RLL (1, 7) encoded,
Assuming that mark edge recording is performed, the mark length and the space length are limited to the range of 2T to 8T. Therefore, selection data of the pulse level for realizing the pulse waveform corresponding to each mark length and space length, setting data of the pulse width, and data of the realizable pulse level value are set in the register. become. A specific example of a drive pulse waveform that can be realized by register setting will be described later.

Recording clock WCL from controller 2
The K and the recording data WDATA are supplied to the digital synchronizing unit 31. As the drive pulse generated based on the recording data, in order to control 0.5T as a unit pulse period, the digital synchronizer 31 generates twice the recording clock WCLK ′ by, for example, PLL processing, and generates this. It is supplied to the pulse generator 32 together with the recording data WDATA.

On the other hand, the register 33 stores control information based on the setting data in the pulse generator 32 and the pulse selector 34.
To supply. The pulse generator 32 outputs the recording data WDAT
A switching pulse for generating a necessary drive pulse (a selection gate signal for a drive pulse at the time of recording) is generated based on A and control information (mode and the like) and supplied to the pulse selector 34. On the other hand, in addition to the selection gate signal from the pulse generator 32, options such as reproduction and erasure are supplied to the pulse selector 34 by control information. These signals are used as switching control signals for the switch 35.

As described above, nine levels are set in the register as drive pulse levels (pulse peak values). The digital value set for each level is
Each is supplied to nine D / A converters 36-1 to 36-9. Therefore, the D / A converters 36-1 ... 36-
9 output pulse voltage values as set levels, and these are supplied to the t1 to t9 terminals of the selector. The t10 terminal is a terminal for selecting an off-level (laser power is a bias level in the subsequent APC unit 16), and corresponds to a level "cool" described later.

Each of the nine levels supplied to the terminals t1 to t9 is referred to by the following name for explanation. That is, "3T
E, nTE, nTM, MTS, MTB, Pr
eH3T, PreHMid, PreHend, R
ead ". Of these, "3TE", "nTE", "n
"TM", "MTS" and "MTB" are levels for forming marks on the disk 6, "PreH3T", "PreHM".
“id” and “PreHend” are levels for applying preheating (preheating).

The selector 35 selects the terminals t1 to t10 and outputs them as drive pulses. Nine levels of voltages are constantly supplied to each terminal of the selector 35. Therefore, a terminal (t1) that selects every 0.5T period (unit pulse period) based on the switching control signal from the pulse selector 34 By switching the (t10 terminal), ten levels can be selected for each 0.5T period, whereby a drive pulse having a desired pulse waveform can be output. The switching timing is 0.5
By setting every T period, the pulse width as one certain level can be selected from 0.5T to 8T.
Specific pulse waveform examples in various cases according to the recording data will be described later.

The drive pulse output from the LPC 4 in this manner is supplied to the APC amplifier 41 in the APC section 16 as a target value of the laser drive level. The APC section 16 is a part that drives a laser diode LD disposed in the optical pickup 7. Here, a part of the laser output from the laser diode LD is detected (photoelectric conversion detection) by the photodiode PD, and a voltage value corresponding to the laser power detection value is supplied to the APC amplifier 41 by the resistor R2. That is, the APC amplifier 4
1 generates a drive current according to a drive pulse voltage as a target value, and applies the drive current to the transistor Q to cause the laser diode LD to emit laser light. Further, at that time, the drive current is controlled according to the voltage value as the laser power detection value. That is, the driving current Iout and the current I corresponding to the detected laser power value
m is controlled so as to maintain the relationship of Iout = k · Im. (K is a coefficient) Thereby, the laser emission operation is performed by the laser power as the target value given as the drive pulse.

2. Example of Drive Pulse Level Setting As understood from the above configuration, in the case of this example, the drive pulse waveform has nine types of levels and off-levels, and one level.
Zero levels can be selected, and by switching levels in 0.5T period units, pulses of various waveforms can be generated.

This is merely an example. Here, the meaning of each level described above and examples of pulse heights will be described with reference to FIGS.
FIG. 3 is a table showing examples of the meanings of the respective levels and the length of a period for maintaining the levels. However, "cool"
The ten levels that can be selected including the level, the definition of each level shown in FIG. 3, and the example of the pulse period length are set for the description of the waveform examples shown in FIG. This is just one example.

First, the level "3TE" is a level used as the last pulse when forming a 3T mark. The pulse width of this level “3TE” is 0.5T. The level “nTE” is a level used as the last pulse when forming 4T to 8T marks. The pulse width of this level “nTE” is 0.5T.
The level “nTE” is also referred to as a pulse level for the laser power at the time of erasing (= level “erase”).

The level "nTM" is a level used as a pulse generated in the middle of forming 4T to 8T marks. The pulse width of this level “nTM” is 0.
5T. The level “MTS” is a level used as a second pulse when forming 2T to 8T marks. The pulse width of this level “MTS” is 0.5T
Or 1T. The level “MTB” is a level used as a leading pulse when forming 2T to 8T marks. The pulse width of this level “MTB” is 0.5T
Or 1T.

The level "PreH3T" is a level used as a pre-heat pulse used during the period of the 3T space. The pulse width of this level “PreH3T” is 0.5T to 2T. Level "PreHMid"
The level is used as an intermediate preheat pulse during the period of 4T to 8T space. This level "Pr
eHMid ”pulse width is 0.5T or co
ol variable depending on the length. Level "Pr
"eHEnd" is a level used as the last preheat pulse in the period of 4T to 8T space.
It is assumed that the pulse width of this level “PreHEnd” is variable depending on the cool length.

The level "Read" is a level corresponding to the laser power during reproduction. However, it can be used at the time of recording as described later. Level "cool"
Corresponds to the off level as described above. The period length of the level cool in the space period is such that the combination of the start cool and the end cool sandwiching the preheat is 1T / 1.
The relation of T or the relation of 0.5T / 1.5T is set. Alternatively, it is assumed that each of the start cool and the end cool can be independently set from 0.0T to 1T.

FIG. 4 shows an example of the level values of these levels. For example, assuming that the levels are set in the order listed in the table of FIG. 3, the vertical relationship between the levels is set as shown in FIG. In this example, the level “3TE” is the maximum level. However, since the actual value (peak value) of each level is determined by the value set in the register 33, the vertical relationship of the levels is not necessarily set as described above. For example, nTE> 3Te It is also possible to perform three preheat levels "Pr
The vertical relationship between eH3T, PreHMid, and PreHEnd may be variously considered in addition to FIG. These settings correspond to the type of the disk 6, correspond to an error condition at the time of recording, and further, the DSP 15 updates the register set value based on the control of the controller 2 in accordance with a user setting operation or the like. Can be arbitrarily changed by changing

Of course, the preheat level "Pr
eH3T, "PreHMid", "PreHEnd", and the level "Read" must be within a range in which no mark is formed on the disk 6, and similarly, the levels "3TE", "nTE", "nTM", "MTS"
Needless to say, “MTB” must be set to a level within a range in which a mark can be formed on the disk 6.

Also, as can be seen from the definitions of the above nine levels, in the case of this example, the level of the last pulse "3TE" used especially for the 3T mark and the level of the last pulse used for the 4T to 8T marks " nTE "are set separately. In the preheat level, a level “PreH3T” used in the 3T space and “PreHMid” and “PreHEnd” used in the 4T to 8T space are separately set.

As a result, a mark space of 4T or more in which the heat accumulation amount on the recording track is relatively large,
The laser power can be controlled separately from the 3T mark space. That is, setting the laser level for the 3T period is advantageous for precise recording data string shaping.

3. Example of Drive Pulse for Mark Formation Hereinafter, an example of a drive pulse realized by finely controlling each level and the pulse period at each level (that is, switching control of the switch 35) as described above will be described.
It is understood from the description of the configuration in FIG. 2 that the waveform of the drive pulse from the LPC 4 corresponds to the transition of the output power from the laser diode LD.

FIGS. 5 to 8 show 2T marks and 3T marks, respectively.
An example of a drive pulse for forming a mark, a 4T mark, and an 8T mark is shown. In each figure, the mark formed in the upper part is shown, and the drive pulse is shown in the lower part. The vertical broken lines are provided at 0.5T intervals. In each figure, three types of pulse examples are shown as mode a, mode b, and mode c. In each mode, a difference appears in the waveform in the first 2T period.

First, an example of a drive pulse for forming a 2T mark will be described with reference to FIG. The 2T period at the beginning of the mark is
Assuming that the pulses of the above-mentioned levels “MTB” and “MTS” are used, in the case of a 2T mark, the mark ends in the 2T period, so that a pulse waveform in which the levels “MTB” and “MTS” are combined is obtained. Here, the level "M
Each pulse period of “TB” and “MTS” is 0.5
The difference between being able to select T and 1T is the mode a, b,
c.

The mode a is a mode in which the pulse width of the level "MTB" is 1T and the pulse width of the level "MTS" is 0.5T. Thus, as shown, the first 1T
The period is level “MTB”, the next 0.5T period is level “MTS”, and the last 0.5T is level “PME”.
Becomes Note that the level “PME” and the level “PM” to be described later are not the names of the above nine types of levels, but indicate the pulse levels used as the cooling period in the drive pulse during mark formation. ("PM" means the cooling level applied in the middle of the mark period, and "PME" means the cooling level applied at the end of the mark period.)

The actual levels as the levels “PME” and “PM” are “PreH3T”, “PreHMi”
d, "PreHend", "Read", and "cool" can be arbitrarily selected by setting. In the sections of the levels “PME” and “PM” shown in each of FIGS. 5 to 8, the levels are indicated by five levels of solid lines and broken lines, and the five levels are “PreH3T” and “Pre”, respectively.
HMid ”,“ PreHend ”,“ Read ”,“ coo ”
l ", and expresses that one of the levels is taken.

Therefore, as the drive pulse for the 2T mark in mode a, there are five types of pulse waveform options depending on the selection of the level PME. Hereinafter, although repeated description is omitted, in the modes b and c of FIG. 5 and FIGS. 6 to 8, the respective pulse waveforms illustrated as levels “PM” and “PME” have the levels “PreH3T” and “PreHMid”. "PreHEn
By selecting from among "d", "Read", and "cool", there are various options.

As will be described, the provision of the cooling period as the level “PM” or “PME” in the drive pulse at the time of forming the mark prevents the temperature on the recording surface from rising excessively, etc. The most suitable level for this purpose is selected from five levels according to the recording data density, the characteristics of the disk, and the like.

Next, mode b is a mode in which the pulse width of the level "MTB" is 0.5T and the pulse width of the level "MTS" is 1T. As a result, as shown in the figure, the first 0.5T period becomes the level "MTB", the next 1T period becomes the level "MTS", and the last 0.5T becomes the level "PMS".
E ".

Mode c is a mode in which the pulse width of the level "MTB" is 0.5T and the pulse width of the level "MTS" is 0.5T. As a result, as shown in the figure, the first 0.5T period is level “MTB”, the next 0.5T period is level “PM”, and the next 0.5T period is level “MT”.
S ", and the last 0.5T becomes the level" PME ".

As shown in FIG. 5, the waveform of the drive pulse for forming the 2T mark can be selected in various ways by setting the mode and setting the levels used as the levels "PM" and "PME". In other words, mode or "PM"
By setting the “PME” corresponding level in the register 33, the drive pulse waveform for generating the 2T mark can be flexibly set. Further, as described above, the actual level values such as the actual levels “MTB” and “MTS” can also be changed by the set value in the register 33, thereby expanding the variety of waveforms that can be output. This is naturally the same for each of the levels shown in FIGS.

Next, an example of a drive pulse for forming a 3T mark will be described with reference to FIG. Since the first 2T period of the mark is the same as that of the 2T mark, the modes a, b,
c, the levels “MTB” and “MTS” and the level “P
M ”generates a waveform as described with reference to FIG. (In the modes a, b, and c in FIG. 6, the first 2T period is the same as each of the modes a, b, and c in FIG. 5.) In the case of the 3T mark, the last 1T of the mark is used.
As a period, a 0.5T period of a pulse of level “3TE” and a 0.5T period of a level “PME” are added. Various pulse waveforms can also be realized by setting the drive pulse for forming the 3T mark.

Further, in the case of forming a 3T mark, the level “3TE” dedicated to the 3T mark is used, so that a fine laser power setting for forming the 3T mark can be made separately from the case of forming a 4T mark or more described below. It becomes possible. In other words, in this example, another level can be used when forming 2T marks, when forming 3T marks, and when forming 4T to 8T marks. As described above, the difference between the 2T mark which is the shortest mark, the mark of 4T or more, and the 3T mark has a difference in the storage temperature characteristic of the laser on the recording surface, so that the 2T mark, the 3T mark, and the 4T to 8T marks are different. Using different levels of pulses during each formation
Very precise mark formation can be realized.

Next, an example of a drive pulse for forming a 4T mark will be described with reference to FIG. The 2T period at the beginning of the mark is the same as that for the 2T mark. That is, modes a, b,
c, the levels “MTB” and “MTS” and the level “P
M ”generates a waveform as described with reference to FIG. (In the modes a, b, and c of FIG. 7, the first 2T period is the same as each of the modes a, b, and c of FIG. 5.) In the case of the 4T mark, the third T period is
The level "nTM" for the 0.5T period and the level "PM" for the 0.5T period, and the last 1T period is the level "nTE" for the 0.5T period and the level "PME" for the 0.5T period.
Becomes Various pulse waveforms can be realized by setting the drive pulse for forming the 4T mark. Further, as described above, the use of the different levels “nTE” and “nTM” in the case of forming the 3T mark enables precise mark formation.

FIG. 8 shows an example of a drive pulse for forming an 8T mark, but the 4T to 8T marks are basically the same. That is, as can be seen by comparing FIG. 7 and FIG.
In the T to 8T marks, the number of pulses of the level “nTM” and the number of pulses of the level “PM” to be added only differ due to the difference between the lengths of the mark periods.

The examples of the drive pulse waveforms for forming the marks have been described above. However, these are supposed to be within the ranges of the level types, level definitions, and pulse period lengths described with reference to FIGS. This is just an example that can be realized in. As described above, FIGS. 3 and 4 are only examples, and if the definition (use method) of each level and the selection range of the pulse period length are changed, various drive pulse waveforms not illustrated can be realized. Needless to say.

4. Example of Drive Pulse for Forming Space Next, similarly, each level and the pulse period at each level as described above are finely controlled (that is, switching control of the switch 35).
The drive pulse in the space period will be described as an example of the drive pulse realized by the above operation. In this example, mode 1 and mode 2 can be set as the drive pulse waveform in the space period, and the case of mode 1 will be described first.

FIGS. 9 to 11 show examples of drive pulses for forming 2T space, 3T space, 4T and 8T space in mode 1, respectively. As in the drawings used for the description of the mark formation, the upper space in each drawing shows the space formed, and the lower row shows the drive pulse. Vertical broken lines are provided at 0.5T intervals.

First, an example of a drive pulse for forming a 2T space in mode 1 will be described with reference to FIG. Here, the mode 1 is the level “c” at the beginning and end of the space period.
"cool" period length, the combination of 1.5T and 0.5T,
Alternatively, the mode is limited to a combination of 1T and 1T. As shown in FIG. 11, which will be described later, in this mode 1, the pulse period of the level “PreHMid” is fixed to 0.5T, while the pulse period of the level “PreHEnd” is variable according to the space length. I do.

As shown in FIG. 9, 2T in mode 1
In the space period, the 2T period is the level “cool”
Becomes This means that the start and end cool
Regardless of the combination of 1.5T and 0.5T or the combination of 1T and 1T, the total of the period of the level “cool” is 2T, so that in the 2T space period, the entire 2T period is This is the level "cool".

FIG. 10 shows an example of a drive pulse for forming a 3T space in mode 1. In this case, as shown in the figure, the level “PreH3
A pulse “T” is added. Then, when the period of the start cool and the end cool is a combination of 1.5T and 0.5T or a combination of 1T and 1T, Example 1,
As shown in Examples 2 and 3, drive pulse waveforms of three patterns can be considered.

That is, the start cool period is 1T, the end cool period is
In the example 1, the pulse period of “PreH3T” is added to the central 1T period, and the start cool period is 0.5T and the end cool period is 1.5.
T, and a pulse of level “PreH3T” is added in the central 1T period near the head, and in Example 2, further, the head coo is added.
l period is 1.5T, terminal cool period is 0.5T,
Level "PreH3T" pulse is 1T at the center near the end
Example 3 is added to the period.

FIGS. 11A and 11B show examples of drive pulse waveforms when a 4T space and an 8T space are formed, respectively. First, in FIG.
In the same manner as in the case of the 3T space, drive pulse waveforms of three patterns can be considered as shown in Example 1, Example 2, and Example 3 depending on the combination of the periods of “ol” and “end” cool. Further, as described above, the pulse period of the level “PreHMid” is fixed to 0.5T and the level “PreHEn”
The pulse period of "d" is variable according to the space length.

In Example 1, the start cool period is 1T and the end c
The cooling period is set to 1T, and 0.
A pulse of 5T level “PreHMid” is added. Then, after an intermediate cool period of 0.5T, the level “PreH” is reached for a 1T period until the end cool is reached.
"End" pulse. Example 2
Is 0.5T for the start cool period and 1.5T for the end cool period, during which the level “PreHMid” of 0.5T, the middle cool of 0.5T,
Each pulse of the T level “PreHEnd” is added. Further, in Example 3, the start cool period is set to 1.5T and the end cool period is set to 0.5T.
Each pulse of 0.5T level “PreHMid”, 0.5T middle cool, and 1T level “PreHEnd” is added.

The case of the 8T space shown in FIG. 11B is basically the same, and three patterns of three patterns as shown in Example 1, Example 2, and Example 3 depending on the combination of the period of the leading cool and the last cool. A drive pulse waveform is conceivable. However, in this mode 1, the level "PreHMid"
Is fixed to 0.5T, and the level “PreHE
Since the pulse period of “nd” is variable according to the space length, as can be understood by comparing FIGS. 11A and 11B, in the case of this 8T space, the pulse of the level “PreHEnd” is used. The difference is that the period is 5T.

Although not shown, in each of the 5T, 6T, and 7T space periods, as can be understood from FIGS. 11A and 11B, the level "PreHEnd" is set according to the period length.
Are set.

The example of the drive pulse waveform in the space period in the mode 1 has been described above. Next, the case of the mode 2 will be described.

FIGS. 12 to 14 show examples of drive pulses for forming 2T space, 3T space, and 4T space in mode 1, respectively. As in the drawings used for the description of the mark formation, the upper space in each drawing shows the space formed, and the lower row shows the drive pulse. Vertical broken lines are provided at 0.5T intervals. However, the drive pulse shown in the lower part of the space indicates a possible level (waveform transition) by a broken line in the pulse, and a specific pulse waveform is further shown in the lower part in Example 1.
To Example 9.

In this mode 2, although the definition deviates from the definition in FIG. 3, the level "PreH3T" is used for preheating in the 2T space period, and the level "PreHMid" is changed in the 3T space period to the 4T-8T period. The mode uses the level “PreHend”. Then, the level “cool” at the beginning and end of the space period
The period length can be set independently from 0.0T to 1.0T. Furthermore, "PreH3T""PreHMi
d ”and“ PreHend ”pulse periods are co
It is supposed to be variably set in accordance with the length.

FIG. 12 shows an example of a drive pulse for forming a 2T space in mode 2 as described above. As shown in the figure, in the 2T space period, the start cool length and the end cool length can be set independently of each other,
In each of the combinations, the level "P
reH3T "will be added. Example 1 shows a drive pulse waveform that is actually enabled under the definition of mode 2.
To the twelfth example, and the right side shows the start cool length, PreH3T pulse length, and end cool length in each pulse waveform.

In Example 1, the start cool length and the end cool length
Since each of the lengths is 1T, all the 2T space periods are at the level “cool”. Example 2 is the first cool
Since the length and the end cool length are 1T and 0.5T, respectively, the level "PreH"
3T ”is added. Example 3 is the first cool
By setting the length and the end cool length to 1T and 0.0T, respectively, the 1T period following the leading cool is at the level “Pre
The waveform becomes “H3T”. Hereinafter, examples 4 to 12 show examples of pulse waveforms in which the level “PreH3T” is added to the remaining period according to the setting of the start cool length and the end cool length, respectively.

Next, FIG. 13 shows an example of a drive pulse for forming a 3T space in mode 2. As shown in the figure, in the 3T space period, the start cool length and the end cool length are set mutually, and the level “PreHMid” is added to the remaining period. Drive pulse waveforms that are actually enabled under the definition of mode 2 are shown as Examples 1 to 12, and on the right side, the leading cool length, PreHMid pulse length,
The end cool length is shown.

In Example 1, the start cool length and the end cool length are each 1T, and the central 1T period is the level “Pr”.
eHMid ”. Example 2 is
The l length and the end cool length are 1T and 0.5T, respectively, and the level “P” is set as the remaining 1.5T period on the center end side.
reHMid ”. In Example 3, the start and end cool lengths are 1T and 0.0T, respectively.
And the 2T period following the top cool is the level “Pre
HMid ”. Hereinafter, Examples 4 to 12
Up to this, an example of a pulse waveform in which the level “PreHMid” is added to the remaining period in accordance with the setting of the start cool length and the end cool length is shown.

Next, an example of a drive pulse for forming a 4T space in mode 2 is shown in FIG. As shown, in the 4T space period, the start cool length and the end cool length are set mutually, and the level “PreHEnd” is added to the remaining period. Drive pulse waveforms that are actually possible under the definition of mode 2 are shown as Examples 1 to 12, and on the right side, the leading cool length, PreHEnd pulse length,
The end cool length is shown.

In Example 1, the start cool length and the end cool length are each 1T, and the center 2T period is the level "Pr".
eHEnd ". Example 2 is
The l length and the terminal cool length are 1T and 0.5T, respectively, and the level “P” is set as the remaining 2.5T period on the center terminal side.
reHend ". In Example 3, the start and end cool lengths are 1T and 0.0T, respectively.
And the 3T period following the top cool is the level “Pre
HEnd ". Hereinafter, Examples 4 to 12
Up to this, an example of a pulse waveform in which the level “PreHEnd” is added to the remaining period according to the setting of the start cool length and the end cool length is shown.

Although the drive pulse waveforms from the 5T space to the 8T space are not shown, basically, as in the case of the 4T space in FIG.
The cool length and the terminal cool length are set mutually,
The level “PreHend” is added to the remaining period.
Therefore, only the period length of the level “PreHend” is different from each example of FIG.

The examples of the drive pulse waveforms for forming the space have been described separately for Mode 1 and Mode 2. However, these are also similar to the drive pulse waveform examples for forming the marks described above with reference to FIGS. This is only an example that can be realized within the range of the level type, the level definition, and the pulse period length example described above (however, mode 2 is not mentioned in FIGS. 3 and 4). Therefore, it is needless to say that various drive pulse waveforms not illustrated can be realized even in the space forming period if the definition (use method) of each level and the selection range of the pulse period length are changed. Of course, "PreH3T" as a preheat level
Since the respective values of “PreHMid” and “PreHEnd” can be changed, more various drive pulse waveforms can be realized. In both modes 1 and 2, 2T
By using different preheating levels for the space, the 3T space, and the 4T to 8T space, fine preheating control can be realized according to the space length.

Although the example of the drive pulse waveform which can be realized in the recording / reproducing apparatus of the embodiment has been described above, in this example, the recording conditions and the properties of the recording medium are selected from the drive pulse waveforms which can be set as described above. An optimum pulse may be selected according to the recording density. This allows
In particular, it can cope with a case where more precise mark formation control is required under high density. In this example, a highly precise recording data sequence (mark and space) can be formed by performing fine laser power control even during the space period. In addition, this makes it possible to flexibly cope with future format changes and recording medium changes.

The configuration and operation of the recording / reproducing apparatus are not limited to those shown in FIGS. In FIG. 2, nine D / A converters are provided to generate nine types of levels. However, there are actually combinations of pulse levels that are not necessary at the same time (for example, the above-described various waveform examples will be described later). If you want to cover, level "PreH3
T ”and“ PreHend ”, levels“ 3TE ”and“ nT ”
E "), and by switching the value (pulse level value) supplied to the D / A converter, the number of D / A converters and the number of terminals of the switch 35 can be reduced. Although the above "cool" level corresponds to the bias level for the laser diode, it may be a level at which laser emission is completely turned off.

In the present invention, the recording processing method and the like are not limited. For example, other recording methods such as RLL (2-7)
An LL modulation method or another modulation method may be used. Of course, if the modulation method is changed, the range of the mark length may not be limited to the above 2T to 8T, but it goes without saying that the drive pulse waveform can be finely controlled according to the mark length and the space length, respectively. Absent. Further, the recording and reproducing apparatus corresponding to a magneto-optical disk has been described, but the present invention can be applied to a reproducing apparatus corresponding to another recording medium.

[0089]

As can be seen from the above description, according to the present invention, a plurality of mark forming levels, a plurality of preheat levels, and an off level can be switched as drive pulse levels. Is switched, a drive pulse having an arbitrary pulse waveform is generated and supplied to the laser means. The drive pulse is generated to form a mark and a space based on the recording data. In particular, as a drive pulse in a section where a space is formed, a pulse set according to the space length is used. A drive pulse having a waveform is generated. That is,
As a level for preheating (preheating), it is possible to switch to a plurality of stages, thereby enabling fine control of laser power even during the space period, and further according to the space length (different for each space length). 3.) There is an effect that fine laser power control becomes possible.

The pulse waveform set according to the space length is a pulse waveform that can be realized by selecting a certain level from a plurality of preheat levels and off levels for each unit pulse period. Thus, a drive pulse waveform for each space length can actually generate various and fine pulses. Further, the setting of the pulse waveform in the space period can be changed by register data, so that the optimum setting can be flexibly realized according to various situations such as the recording density and the type of recording medium.

From the above, not only is it suitable as a recording apparatus and recording method corresponding to high-density recording, but it is also possible to flexibly cope with future recording methods and specifications of recording media and to improve compatibility. Suitable light modulation type recording, such as easy maintenance, can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of a recording and reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of an LPC and an APC unit according to the embodiment.

FIG. 3 is an explanatory diagram of an example of a pulse level according to the embodiment;

FIG. 4 is an explanatory diagram of an example of a peak value of each pulse level according to the embodiment;

FIG. 5 is an explanatory diagram of a drive pulse waveform when a 2T mark is formed according to the embodiment.

FIG. 6 is an explanatory diagram of a drive pulse waveform when a 3T mark is formed according to the embodiment.

FIG. 7 is an explanatory diagram of a drive pulse waveform when a 4T mark is formed according to the embodiment.

FIG. 8 is an explanatory diagram of a drive pulse waveform when an 8T mark is formed according to the embodiment.

FIG. 9 is an explanatory diagram of a drive pulse waveform when a 2T space is formed in mode 1 of the embodiment.

FIG. 10 is an explanatory diagram of a drive pulse waveform when a 3T space is formed in mode 1 of the embodiment.

FIG. 11 shows 4T space and 8 in mode 1 of the embodiment.
FIG. 4 is an explanatory diagram of a drive pulse waveform when a T space is formed.

FIG. 12 is an explanatory diagram of a drive pulse waveform when a 2T space is formed in mode 2 of the embodiment.

FIG. 13 is an explanatory diagram of a drive pulse waveform when a 3T space is formed in mode 2 of the embodiment.

FIG. 14 is an explanatory diagram of a drive pulse waveform when a 4T space is formed in mode 2 of the embodiment.

FIG. 15 is an explanatory diagram of a conventional drive pulse.

[Explanation of symbols]

1 host computer, 2 controllers, 3 CP
U, 4 LPC, 6 disc, 7 optical pickup, 1
5 DSP, 16 APC, 20 RF block, 31
Digital synchronization section, 32 pulse generator, 3
3 registers, 34 pulse selectors, 35 switches, 36-1 to 36-9 D / A converters, 41 APC
Amplifier

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuru Imai 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5D075 BB04 CC05 CC22 CD02 CD12 5D090 BB04 CC01 DD03 DD05 EE02 FF11 FF30 FF31 GG26 HH01 KK05

Claims (6)

[Claims] 1. A laser means for irradiating a laser beam with a supplied drive pulse to form a recording data sequence comprising marks and spaces between marks on a recording medium, and forming a plurality of marks as drive pulse levels. A level, a plurality of preheat levels, and an off level. The drive can generate a drive pulse having an arbitrary pulse waveform by switching the level every unit pulse period and supply the drive pulse to the laser unit. Pulse generating means, and causing the drive pulse generating means to generate a drive pulse for forming the mark and the space based on the recording data, and as the drive pulse in a section in which the space is formed, the drive pulse has a length corresponding to the space length. Pulse to generate drive pulse of pulse waveform set according to Recording apparatus comprising: the shape control means. 2. A pulse waveform set according to the space length is a pulse waveform that can be realized by selecting a certain level from among the plurality of preheat levels and off levels for each unit pulse period. 2. The recording apparatus according to claim 1, wherein: 3. The pulse waveform control means has a register unit for storing a setting of a pulse waveform corresponding to the space length, and the setting data in the register unit is updated, so that the pulse waveform control unit responds to the space length. 2. The recording apparatus according to claim 1, wherein the setting of the pulse waveform is changed. 4. A recording method for generating a drive pulse based on recording data and irradiating a laser beam with the drive pulse to form a recording data sequence including marks and spaces between marks on a recording medium, wherein: As the level of the drive pulse, a plurality of mark formation levels, a plurality of preheat levels, and an off level can be switched for each unit pulse period, and the drive pulse in a section where the space is formed has a space length. A recording method comprising: generating a drive pulse having a pulse waveform set in accordance with the drive pulse. 5. A pulse waveform set according to the space length is a pulse waveform that can be realized by selecting a certain level from among the plurality of preheat levels and off levels for each unit pulse period. 5. The recording method according to claim 4, wherein: 6. The setting of the pulse waveform according to the space length is stored in a register unit, and the setting of the pulse waveform according to the space length is changed by updating the setting data in the register unit. 5. The recording method according to claim 4, wherein: