JP3516116B2 - Optical recording device and recording mark recording method - 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 recording device and a recording mark recording method. For more information, recorded de
The data length is determined based on the data
Modulation data that is K a ( K a is an integer of 2 or more ) times the data length of
Data, and synchronizes with this modulated data.
Is 1 / K b ( K b is 2
Reference clock signal having a higher integer) times the period
Signal based on the reference clock signal.
1 / K e ( K e is an integer of 2 or more ) times the reference clock signal
Generate a second clock signal having a period of
(The K d 2 or more integer) of the clock signal to 1 / K d division to
Generate a first clock signal and generate the first clock signal
The laser emission pattern of the laser irradiation means synchronized with
Generate and generate modulated data based on the laser emission pattern
The corresponding recording mark is formed on the optical recording medium .

[0002]

2. Description of the Related Art In an optical disk which is an optical recording medium, for example, a phase change optical disk in which data can be written by controlling the power of irradiated laser light to change the reflectance of a recording layer, FIGS. As shown in FIG. 8, the recording data WD (FIG. 8A) is, for example, pulse-width modulated at the time of data recording, and the reference clock signal RCK (FIG. 8) is generated.
The modulated data MD (FIG. 8C) is synchronized with B). A laser drive signal is generated based on this modulation data MD, and for example, during a period when the signal level of the modulation data MD is a high level “H” indicating the formation of a recording mark (time t1 to time t2 and time t3 to time t4), Laser power (Fig. 8
In D), the reproduction level is changed from "W1" to "W2".
At this time, the recording layer of the optical disc is set to a temperature higher than a predetermined temperature to form a recording mark (FIG. 8E).

By the way, the size of the recording mark becomes larger than the recording mark (FIG. 8F) of an appropriate size corresponding to the recording data due to thermal diffusion of the optical disk. Therefore, when the optical disc on which the recording marks are formed is reproduced, the error rate becomes high, and this phenomenon becomes remarkable especially when data is recorded at high density.

Therefore, in order to record the data at a high density and prevent the error rate from increasing, the laser power is controlled in a pulsed manner at the time of recording so that the size of the recording mark is appropriate according to the recording data. The so-called pulse train recording method is used.

This pulse train recording system is shown in FIG.
A description will be given using A to E. In the pulse train recording method, the laser power is controlled in a pulsed manner in synchronization with the reference clock signal RCK, for example, when the modulated data MD is in the recording mark forming period. That is, during the period when the modulation data MD (FIG. 9C) of the recording data WD (FIG. 9A) is at the high level “H” indicating the formation of the recording mark (time t11 to time t15), the reference clock signal RCK is generated.
When (FIG. 9B) is first set to the low level “L”, the laser power (FIG. 9D) is set to “W1” during the period in which the reference clock signal RCK is set to the low level “L” (time t11 to time t12). "To W3". After that, during the period in which the reference clock signal RCK is at the low level "L" (time t13 to time t14), the laser power is "W".
4 ”. Furthermore, the reference clock signal RCK
Is raised to the high level "H", the laser power is set to "0" during one cycle period of the reference clock signal RCK (time t14 to time t16). After that, the laser power is set to "W1" until the time t17 when the modulation data MD is set to the high level "H" next time.

As described above, during the recording mark formation period, the laser power is controlled in a pulsed manner to form the recording mark (FIG. 9E) corresponding to the recording data WD.

[0007]

By the way, the irradiation period of the laser beam in the pulse train recording system is shorter than the minimum inversion period of the recording data, and further shortened as the recording density of the data becomes higher. For this reason, distortion is likely to occur during signal transmission, and for example, during the period when the modulation data MD (FIG. 9C) is at the high level “H” indicating the formation of the recording mark (time t17 to time t18), the reference clock signal RCK (FIG. 9B) when the low level “L” period is longer than the high level “H” period, the irradiation period of the laser light is long and the size of the recording mark becomes larger than the proper size. .

Therefore, the present invention provides an optical recording apparatus and a recording data recording method capable of recording the recording data while preventing the variation of the irradiation time of the laser beam.

[0009]

An optical recording apparatus according to the present invention is a laser irradiating means for irradiating an optical recording medium with a laser beam, and a data length determined based on recording data.
And the data length of the recorded data is K a ( K a is an integer of 2 or more).
And modulating means for modulating the modulated data as a number) times the modulation de
Data with the shortest data length of modulated data
1 / K b ( K b is an integer of 2 or more ) times the period
Generating a reference clock signal for
The reference clock signal based on the clock signal
The second with a period of 1 / K e ( K e is an integer greater than or equal to 2 ) times
Generates a clock signal and outputs the second clock signal as 1 / K d
( K d is an integer greater than or equal to 2 ) Divide and divide the first clock signal
Clock signal generating means for generating, the modulated data and the first
Based on the clock signal, the laser emission pattern of the laser irradiation means
A laser emission pattern generating means for generating a turn;
The laser irradiation means is driven based on the light emission pattern,
By the laser irradiation means, recording marks corresponding to the modulated data are recorded.
And a control means for forming a recording medium on an optical recording medium
Is. Further, the clock signal generating means is the second clock.
A second clock signal is provided with an oscillating means for generating a signal.
The phase comparison means compares the phase of the output of the frequency dividing means for frequency division and the modulated data, and controls the oscillating means based on the comparison result.

The method of recording the recording mark on the optical recording medium according to the present invention is determined based on the recording data.
The data length of the recorded data is K a ( K a
Modulating the modulated data is 2 or more integer), the modulation de
Data with the shortest data length of modulated data
1 / K b ( K b is an integer of 2 or more ) times the period
Generating a reference clock signal for
The reference clock signal based on the clock signal
The second with a period of 1 / K e ( K e is an integer greater than or equal to 2 ) times
Generates a clock signal and outputs the second clock signal as 1 / K d
( K d is an integer of 2 or more ) and divides to generate the first clock signal
Laser emission pattern synchronized with the first clock signal
And generate a modulation data based on the laser emission pattern.
Recording marks corresponding to data is to form on the optical recording medium.

In the present invention, the recorded data is modulated by pulse width modulation, for example, and is synchronized with this modulated data, has a constant duty ratio, and has the shortest data length of 1 / Kb (data period of the modulated data. Kb is 2
A first clock signal having a period of the above integer) is generated. A laser light emission pattern is generated based on the first clock signal and the modulation data, and the laser power of the laser light with which the optical recording medium is irradiated is switched based on the laser light emission pattern to change the time variation of the laser light irradiation. To be prevented.

Further, the frequency division ratio of the frequency dividing means is changed to synchronize with the modulation data, the duty ratio is constant, and 1 / Kb (Kb is an integer of 2 or more) of the minimum period of the modulation data having the shortest data length. It is possible to generate a doubled first clock signal.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the structure of an embodiment of an optical recording apparatus according to the present invention will be described in detail.

FIG. 1 shows the configuration of the first embodiment. In FIG. 1, the recording data WD is supplied to a disk controller 11 which is a modulating means, and the disk controller 11 synchronizes with the recording data WD based on the recording data WD and a reference having a cycle equal to the bit interval T of the recording data WD. The clock signal RCK is generated. Further, the recording data WD is, for example, pulse-width modulated to be modulated data MD which is an integral multiple of the bit interval T of the recording data WD and Ka times the data length of the recording data WD . Further, the control signal CS is supplied to a microcomputer (hereinafter referred to as “microcomputer”) 60, and a power control data signal for setting the power of laser light output from a laser diode 45 described later to a predetermined level is generated. .

Here, the reference clock signal RCK
Has a period equal to the bit interval T, the reference clock signal RCK has a period obtained by multiplying the minimum period of the modulation data MD by 1 / Kb (Kb is an integer of 2 or more).

The reference clock signal RCK generated by the disk controller 11 is supplied to the phase comparator 12 of the clock signal generating means. The phase comparison unit 12 is composed of a phase comparator, a filter, and the like, and performs a phase comparison between the reference clock signal RCK and a frequency division signal DCK obtained by a frequency division unit 14 described later to perform an error signal EP indicating a phase error. Is generated. The error signal EP is supplied to the voltage controlled oscillator 13. The clock signal generating means is composed of a frequency divider 14 that is a voltage controlled oscillator 13 and the frequency dividing means is a transmitter means and the phase comparison unit 12 is a phase comparing means.

In the voltage controlled oscillator 13, the reference clock signal RCK and the divided signal D are generated based on the error signal EP.
The oscillation frequency is controlled so that the frequency and phase of CK match, and the master clock signal MCK which is the second clock signal is generated. This master clock signal M
The frequency division unit 14 divides the frequency CK into 1 / Kd to generate a light emission clock signal LCK which is the first clock signal and the frequency 1 / Ke to generate a frequency division signal DCK. Note that "Kd" and "Ke" are integers of 2 or more, and the value of "Kd" is equal to "Ke" or "Ke".
Is set to a smaller value. The generated light emission clock signal LCK is supplied to the mark length determination unit 15 and the light emission pattern output unit 16 which are laser light emission pattern generation means, and the frequency division signal DCK is supplied to the phase comparison unit 12.

The operation of generating the light emission clock signal LCK will be described with reference to FIGS. 2A to 3E and 3A to 3E.
For example, assuming that the reference clock signal RCK (FIGS. 2B and 3B) has a cycle that is 1/2 times the minimum cycle of the modulation data MD (FIGS. 2A and 3A), “Kd”,
Assuming that "Ke" = 2, the master clock signal MCK (FIG. 2C) has a frequency-divided signal D obtained by dividing the master clock signal MCK into 1/2 as shown in FIGS.
The frequency is controlled such that the rising edges of CK (FIG. 2D) and the reference clock signal RCK are synchronized and the frequencies become equal. That is, the master clock signal MCK which is in synchronization with the reference clock signal RCK and whose period is ½ of the period of the reference clock signal RCK is generated. Therefore, the light emission clock signal LCK (FIG. 2E) obtained by dividing the master clock signal MCK by ½ has a cycle that is in synchronization with the modulation data MD and that has a cycle obtained by multiplying the minimum cycle of the modulation data MD by ½. To have. Further, since the light emission clock signal LCK is a signal obtained by dividing the master clock signal MCK in half, the reference clock signal RCK
The duty ratio of the light emission clock signal LCK is constant even if the duty ratio of the reference signal RCK changes from the time t21 to the time t22.

If "Kd" = 2 and "Ke" = 3, the master clock signal MC is generated as shown in FIGS.
The divided signal DCK (see FIG. 3C) obtained by dividing K (FIG. 3C) into 1/3.
The master clock signal MCK is controlled so that the frequencies of D) and the reference clock signal RCK are synchronized and the frequencies become equal to each other. For this reason, the light emission clock signal LCK (FIG. 3E) obtained by dividing the master clock signal MCK by ½ is synchronized with the modulation data MD and has a cycle that is ⅓ times the minimum cycle. It Further, since the light emission clock signal LCK is a signal obtained by dividing the master clock signal MCK in half, the duty ratio of the reference clock signal RCK varies and the reference signal RCK falls from time t31 to time t31. Even if it is changed to t32, the duty ratio of the light emission clock signal LCK is kept constant.

Modulation data MD is supplied from the disk controller 11 to the mark length discriminator 15 to which the light emission clock signal LCK is supplied.
In 5, the light emission clock signal LCK is used to determine how many times the pulse width indicating the recording mark of the modulated data MD is the bit interval T, and the determination result is the light emission pattern output unit 1.
6 is supplied.

The light emission pattern output unit 16 holds a map showing a light emission pattern according to the pulse width of the modulated data MD, and the map corresponding to the pulse width determined by the mark length determination unit 15 is selected. Based on the selected map and the supplied light emission clock signal LCK, the minimum pattern length of the laser light emission pattern is 1 / the period of the light emission clock signal LCK in synchronization with the light emission clock signal LCK.
A pattern signal of 2 is output. It is assumed that a plurality of pattern signals are output according to the number of switching levels of laser power in the pulse train recording method (except when the laser power is "0").

Further, there are provided a plurality of reference signal holding sections and a switch section which constitute a control means in accordance with the number of switching levels of the laser power, and the reference signal holding section has power control data generated by the microcomputer 60. Signal is supplied.
In the reference signal holding unit, each reference signal holding unit generates a reference signal based on the power control data signal and supplies the reference signal to the switch unit. The switch unit is switch-controlled by a pattern signal from the light emission pattern output unit 16. The control means is composed of a reference signal holding unit, a switch unit, a microcomputer, a drive signal generation unit described later, and the like.

For example, when the laser power in the pulse train recording system is switched at three levels, as shown in FIG.
As shown in, the light emission pattern output unit 16 outputs three pattern signals SE1, SE2, SE3. In addition, three reference signal holding units 21, 22, 23 and switch units 31, 32, 3 are provided according to the number of switching levels of laser power.
3 is provided.

The reference signal holding section 21 is composed of a D / A converter, a latch circuit, etc., and the power control data signal PCD1 from the microcomputer 60 is latched and converted into an analog voltage signal to be used as the reference signal RL1. Is supplied to one terminal of the switch unit 31. Similarly, in the reference signal holding unit 22, an analog reference signal RL2 is generated based on the power control data signal PCD2 and supplied to one terminal of the switch unit 32, and in the reference signal holding unit 23, the power control data signal PCD3. The analog reference signal RL3 is generated based on the above, and is supplied to one terminal of the switch unit 33.

The other terminals of the switch units 31, 32 and 33 are connected to the input terminals of the adding unit 41, and the adding unit 41
The output terminal of is connected to the drive signal generation unit 42. For this reason, the drive signal generation unit 42 has the pattern signals SE1, S
Reference signals RL1 and R selected based on E2 and SE3
An addition reference signal RLM obtained by adding L2 and RL3 is supplied.

In the drive signal generator 42, the addition reference signal R
The laser drive signal DR is generated based on LM and a sensor signal PM described later so that the signal levels of the addition reference signal RLM and the sensor signal PM match. The laser drive signal DR is supplied to the base of the transistor 43.

The emitter of the transistor 43 is a resistor 44.
The collector is connected to the cathode of a laser diode 45, which is a laser irradiation means, while being grounded via. The anode of the laser diode 45 is the power supply terminal 50.
The laser diode 45 is driven based on the laser drive signal DR supplied to the base of the transistor 43.

The laser light output from the laser diode 45 is incident on the beam splitter 51 via a collimator lens and a grating (not shown). The laser light passing through the beam splitter 51 is applied to the photodiode 46, and the laser power is monitored.

The cathode of the photodiode 46 is connected to the power supply terminal 50, and the anode thereof is the resistor 47.
Grounded through. Since a photocurrent according to the laser power flows through the photodiode 46, a voltage is generated between the terminals of the resistor 47 by this photocurrent and is supplied to the drive signal generation unit 42 as the sensor signal PM.

In this way, the laser diode 4 is monitored while the laser power is being monitored by the photodiode 46.
5 is driven, the laser power is added to the reference signal RL.
The power level can be constantly controlled based on M, and the laser power can be switched by changing the signal level of the addition signal RML.

The laser light reflected by the beam splitter 51 passes through the objective lens 52 and is applied to the optical disk 10. The laser light reflected by the optical disk 10 is applied to the prism 53 via the objective lens 52 and the beam splitter 51. The laser light applied to the prism 53 is reflected and guided to the light detection unit 55.

The photodetector 55 is constructed by using a photodiode or the like, and an error signal ES indicating a focus error or a tracking error is generated based on the laser light and is supplied to the servo controller 56.

In the servo control unit 56, a focus drive signal and a tracking drive signal are generated based on the error signal ES and supplied to an actuator (not shown), so that the objective lens 52 is driven to perform a focus or tracking servo operation. Be seen.

During reproduction of the optical disk 10, the power of the laser light output from the laser diode 45 is set to a predetermined reproduction level, and the photodetector 55 generates a reproduction signal RS based on the reflected light from the optical disk 10. To be done. The reproduction signal RS is subjected to demodulation processing, error correction processing, etc. in the reproduction signal processing unit 57 and then supplied to the disk controller 11 and output as reproduction data RD.
The optical disc 10 is rotationally driven by the spindle motor 59. The operation of the reproduction signal processing section 57 is controlled by the microcomputer 60.

Next, the operation of the first embodiment will be described with reference to FIGS. The recording data WD, the reference clock signal RCK, the modulation data MD, the master clock signal MCK, and the light emission clock signal LCK shown in FIGS. 4A to 4E are the same as the recording data WD, the reference clock signal RCK, and the modulation data MD shown in FIGS. , Master clock signal MCK, and light emission clock signal LCK.

The mark length discriminating unit 15 discriminates the pulse width indicating the recording mark of the modulated data MD, and based on the discrimination result, the light emitting pattern output unit 16 outputs the pattern signals SE1, SE1.
SE2 and SE3 are output. For example, the modulation data MD
Until is set to a high level "H" indicating a recording mark,
Pattern signal SE1 (FIG. 4F) and pattern signal SE
2 (FIG. 4G) is a low level “L” and the pattern signal SE3
(FIG. 4H) is set to the high level “H” and the switch unit 33
Only is made conductive. Therefore, the reference signal RL3 is supplied to the drive signal generation unit 42 as the addition reference signal RLM, and the laser power (FIG. 4J) is the reproduction level “W”.
1 ”.

Next, the mark length discriminator 15 modulates the modulation data M.
When it is determined that the pulse width indicating the D recording mark is "2T" (T is a bit interval), the light emission clock signal LCK
In the period of 3Q from the time point t41 to the time point t42, where ½ cycle of Q is Q, the pattern signals SE1 and SE3 are at high level “H”, and the pattern signal SE2 is at low level “L”.
It is said that At this time, the switch parts 31 and 33 are in a conductive state and the switch part 32 is in a non-conductive state. Therefore, the added signal of the reference signal RL1 and the reference signal RL3 is supplied to the drive signal generation unit 42 as the added reference signal RVM, and the laser power is set to "W5".

Thereafter, during the period from time t41 to time t43 when the modulated data MD is set to the high level "H" indicating the recording mark, the light emission clock signal LCK is finally set to the high level "H".
From the time point t42 rising to the time point to the time point t44 after the lapse of the 2Q period, the pattern signals SE1, SE2 and SE3 are all set to the low level “L” and the switch parts 31, 32 and 33 are brought into the non-conducting state. The power is "0".

Further, until the next time t45 when the modulation data MD is set to the high level "H", the pattern signals SE1,
SE2 is set to the low level "L", the pattern signal SE3 is set to the high level "H", only the switch section 33 is turned on, and the laser power is set to "W1".

Next, the mark length discriminator 15 modulates the modulation data M.
When it is determined that the pulse width indicating the D recording mark is "4T", the pattern signals SE1 and SE3 are at the high level "H" during the period of 3Q from the time t45 to the time t46.
The pattern signal SE2 is set to the low level "L", the switch portions 31 and 33 are in the conductive state, and the switch portion 32 is in the non-conductive state. Therefore, the reference signal RL1 and the reference signal R
The laser power is set to "W5" based on the addition signal with L3.

After that, from time t46, the pattern signal SE
1 is set to the low level "L" and the pattern signal S
The state of E3 at the high level "H" is held. Further, the pattern signal SE2 is set to the low level “L” from the time point t46 to the time point t47 after the 1Q period has elapsed, and thereafter the signal level is inverted every 1Q period. That is, time point t47
From the 1Q period to the time t48, high level "H"
The low level is set to "L" from the time point t48 to the time point t49 after the 1Q period has elapsed. In the same manner, the inversion of the signal level of the pattern signal SE2 is repeated.

Here, when the pattern signal SE2 is set to the high level "H", the switch section 32 is rendered conductive, so that the addition signal of the reference signal RL2 and the reference signal RL3 is added to the drive signal generation section 42. It is supplied as the reference signal RVM and the laser power is set to "W6".

After that, during the period from time t45 to time t50 when the modulated data MD is set to the high level "H" indicating the recording mark, the light emission clock signal LCK is finally set to the high level "H".
From the time t49 when the signal rises up to the time t51 after the lapse of the 2Q period, the pattern signals SE1, SE2 and SE3 are all set to the low level “L” and the switch parts 31, 32 and 33 are brought into the non-conducting state. The power is "0".

Further, until the next time the modulated data MD is set to the high level "H", the pattern signals SE1, SE
2 is set to the low level "L", the pattern signal SE3 is set to the high level "H", only the switch section 33 is turned on, and the laser power is set to "W1".

Similarly, the mark length discriminating section 15 discriminates the pulse width indicating the recording mark of the modulated data MD, and the pattern signals SE1, SE2, SE3 based on the discrimination result are outputted to control the laser power. Therefore, in FIG.
While the modulation data MD shown in C is at the high level "H" indicating the formation of the recording mark (time point t45 to time point t50), the reference clock signal RCK is distorted and the duty ratio is changed, so that the reference clock signal RCK becomes low. Even if the level “L” period becomes long, the laser power is switched by the pattern signal generated based on the light emission clock signal LCK which is synchronized with the reference clock signal RCK and has a constant duty ratio.
It is possible to form a recording mark (FIG. 4K) having an appropriate size corresponding to the recording data WD.

As described above, according to the above-described embodiment,
Even if the reference clock signal RCK is distorted and the duty ratio is not constant, the master clock signal MCK having a predetermined frequency is generated in synchronization with the reference clock signal RCK. The master clock signal MCK is frequency-divided to generate a light emission clock signal LCK having a constant duty ratio in synchronization with the reference clock signal RCK, and the laser power of the laser light is switched based on the light emission clock signal LCK. It is possible to form a recording mark of an appropriate size according to the recording data WD while preventing the time variation of laser light irradiation and the laser power variation.

By changing the ratio of the multiple of the frequency of the master clock signal MCK to the frequency of the reference clock signal RCK and the division ratio of the master clock signal MCK, the duty ratio is constant while synchronizing with the modulation data, and the most data is obtained. 1 of the minimum period of short modulation data
Since a light emission clock signal that is multiplied by / Kb (Kb is an integer of 2 or more) times can be generated, it is possible to more finely switch the laser power of the laser light to form a recording mark of an appropriate size.

In the above embodiment, the laser power is switched by using the reference signal which is the voltage signal. However, even if the current is changed by the pattern signal, the laser power of the laser light is also predetermined. The pattern can be switched. Next, FIG. 5 shows a configuration of an optical recording apparatus that forms a recording mark by changing the current as a second embodiment. In FIG. 5, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The reference signal holding section 61 is constituted by using a D / A converter or the like, and based on a power control data signal PCD1 from the microcomputer 60, an analog control signal CC1.
Is generated and held, and is supplied to the constant current source 81. Similarly, in the reference signal holding unit 62, the control signal CC2 is generated from the power control data signal PCD2 and supplied to the constant current source 82. In the reference signal holding unit 63, the control signal CC3 is generated from the power control data signal PCD3 and supplied to the constant current source 83.

The constant current source 81 is set so that the reference current CL1 flows by the control signal CC1. Similarly, in the constant current source 82, the reference current CL2 is changed by the control signal CC2.
Is set so that the control signal C
The reference current CL3 is set to flow by C3.

The constant current sources 81, 82, 83 are connected to one terminals of the switch parts 71, 72, 73, respectively, and the other terminals of the switch parts 71, 72, 73 are connected to the drive signal generating part 92. The switch parts 71, 72, 73 are switch-controlled by the pattern signals SE1, SE2, SE3, and the reference currents flowing when the switch parts 71, 72, 73 are made conductive are added to add the reference current C.
The LM is supplied to the drive signal generation unit 92. Although the bias current is added to the addition reference current CLM by the constant current source 85, the bias current will be omitted in the description of the present application.

The anode of the photodiode 46 is connected to the drive signal generator 92, and the addition reference current CLM is used.
The laser drive signal DR is generated based on the photocurrent IM generated by the photodiode 46.

Therefore, when the pattern signals SE1 and SE3 are set to the high level "H", the reference current CL1 and the reference current CL3 are added, similar to the operation when the reference signal which is the voltage signal is used. The laser power is set to "W5" based on this added current. In addition, the pattern signal SE
2, when SE3 is set to the high level "H", the reference current C
L2 and the reference current CL3 are added, and the laser power is set to "W6" based on the added current. When the pattern signals SE1, SE2, SE3 are at low level "L", the laser power is "0". In this way, it is possible to form a recording mark of an appropriate size even if the current is changed by the pattern signal.

Here, when the recording mark is formed by changing the current, the switch parts 71, 72, 73 are provided, for example, in FIG.
It is also possible to use a differential switch as shown in.

In FIG. 6, pattern signals SE1 and SE
2 and SE3 are buffer units 711, 721, 7 respectively.
31 through NPN type transistors 712, 722, 7
Supplied to 32 bases. Also, the buffer units 711, 7
The logic is inverted at 21, 731 and supplied to the bases of NPN type transistors 713, 723, 733. The emitters of the transistors 712 and 713 forming the differential switch are connected to the constant current source 81. Similarly, the emitters of the transistors 722 and 723 are connected to the constant current source 82. The emitters of the transistors 732 and 733 are connected to the constant current source 83. Transistors 712, 722
The collector of 732 is connected to the drive signal generation unit 92.
The collectors of the transistors 713, 723, 733 are connected to the power supply terminal 50 via resistors 714, 724, 734, respectively.

Here, for example, when the pattern signal SE1 is set to the high level "H", the transistor 712 is turned on and the transistor 713 is turned off, so that the reference current CL1 flows through the drive signal generating section 92. To be taken. Further, the pattern signal SE1 is low level "L".
Then, the transistor 712 is turned off, the transistor 713 is turned on, and the resistor 7
The reference current CL1 flows through the drive current generator 14, and the drive signal generator 9
The current flowing through 2 is stopped. The pattern signal SE
2 and SE3 similarly transistors 722 and 72
3, 732 and 733 are driven to control the current flowing through the drive signal generation unit 92.

By the way, in the above-described embodiment, the reference signals RL1, RL2, RL3 and the reference currents CL1, CL2 are used.
Although the laser power is controlled by adding CL3, it is possible to switch to a desired laser power by selecting one reference signal from a plurality of reference signals or selecting one reference current from a plurality of reference currents. It is also possible to set the reference signal and the reference current, respectively, so that they can be performed.

The operation in this case will be described with reference to FIGS. For example, the reference signal RL1 or the reference current CL1 is set so that the laser power is "W5", and the reference signal RL2 or the reference current CL2 is set so that the laser power is "W6". Further, the reference signal RL3 or the reference current CL3 is set so that the laser power becomes "W1" which is the reproduction level. Note that the signals shown in FIGS. 7A to 7E correspond to the signals shown in FIGS.

The optical pattern output section 16 outputs pattern signals SE1 ', SE2', SE3 'for selecting one reference signal from a plurality of reference signals or selecting one reference current from a plurality of reference currents. Is output. For example, until the time t61 when the modulation data MD is set to the high level "H" indicating the recording mark, the pattern signal SE1 '.
(FIG. 7F) and the pattern signal SE2 ′ (FIG. 7G) are at low level “L”, and the pattern signal SE3 ′ (FIG. 7H) is at high level “H”. Therefore, only the switch unit 33 or the switch unit 73 is turned on, and the laser power (FIG. 7J) is set to the reproduction level "W1".

Next, the mark length discriminating section 15 modulates the modulation data M.
The pulse width indicating the D recording mark is discriminated, and the light emission pattern output unit 16 outputs the pattern signal SE based on the discrimination result.
1 ', SE2', SE3 'are output.

When the mark length discriminating unit 15 discriminates that the pulse width indicating the recording mark of the modulation data MD is "2T", the pattern signal SE1 is generated during the period 3Q from the time t61 to the time t62. 'Is high level "H", the pattern signals SE2' and SE3 'are low level "L", only the switch section 31 or the switch section 71 is made conductive, and the laser power is set to "W5".

Thereafter, during the period from time t61 to time t63 when the modulated data MD is set to the high level "H" indicating the recording mark, the light emission clock signal LCK is finally set to the high level "H".
From the time t62 which rises to the time t2 to the time t64 after the lapse of the 2Q period, the pattern signals SE1 ′, SE2 ′ and SE3 ′ are all set to the low level “L” and all the switch parts are brought into the non-conduction state. The power is "0".

Further, from the time t64 to the time t65 when the modulation data MD is set to the high level "H" next time, the pattern signals SE1 'and SE2' are low level "L" and the pattern signal SE3 'is high level "H". And switch section 33
Only becomes conductive, and the laser power is set to "W1".

Next, the mark length discriminator 15 modulates the modulation data M.
When it is determined that the pulse width indicating the recording mark of D is "4T", the pattern signal SE1 'is at the high level "H" and the pattern signals SE2', SE3 during the period of 3Q from the time t65 to the time t66. 'Is set to the low level "L" so that only the switch section 31 becomes conductive and the laser power is set to "W5".

Thereafter, from the time t66, the pattern signals SE2 'and SE3' are alternately set to the high level "H" every time the period of 1Q elapses, and the switch section 32 and the switch section 33 are alternately turned on. Alternatively, the switch section 72 and the switch section 73 are alternately turned on and the laser power is alternately set to "W1" or "W6".

During the period from time t65 to time t68 when the modulation data MD is set to the high level "H" indicating the recording mark, after the lapse of 2Q period from the time t67 when the light emission clock signal LCK finally rises to the high level "H". Until time t69, the pattern signals SE1 ′, SE2 ′, SE3 ′ are all set to the low level “L” and the switch units 31, 32, 33 are brought into the non-conducting state, so that the laser power is set to “0”. It

Until the next time when the modulation data MD is set to the high level "H", the pattern signal SE3 'is set to the high level "H" and only the switch section 33 is made conductive so that the laser power is kept. "W1".

Similarly, the mark length discriminating section 15 discriminates the pulse width indicating the recording mark of the modulation data MD, and the pattern signals SE1 ', SE2', SE based on the discrimination result.
3'is output and the laser power is controlled based on one of the reference signals or the reference current. Therefore, the modulation data MD has a high level “H” indicating the formation of the recording mark.
During the period (time t65 to time t68), even if the reference clock signal RCK is distorted to change the duty ratio and the low level “L” period of the reference clock signal RCK becomes long, the reference clock signal RCK is synchronized with the reference clock signal RCK. In addition, since the laser power is switched by the pattern signal based on the light emission clock signal LCK whose duty ratio is constant, it is possible to form a recording mark (FIG. 7K) of an appropriate size corresponding to the recording data WD. In this case, since the addition unit for adding the reference signal and the reference current is not required, the configuration can be simplified.

The period, the pattern signal, the laser power and the like shown in the above-mentioned embodiments are merely examples and are not limiting. In the above embodiment, the case where data is recorded on the phase change optical disk has been described.
The optical recording medium is not limited to the phase change optical disc, but may be, for example, a magneto-optical disc. Further, it is needless to say that the optical disc is not limited to the rewritable optical disc, and may be a write-once optical disc.

The present invention is not limited to recording by the pulse train method for all data lengths. That is, at least a certain data length may be recorded by the pulse train method, and the above-described operation may be performed at this data length.

[0071]

Effect of the Invention] The present invention, modulation data from the recording data is generated, in synchronization with the modulation data, modulated de
1 / K b for the data period with the shortest data length of data
( K b is an integer greater than or equal to 2 )
A lock signal is generated to enable this reference clock signal.
1 / K e of the reference clock signal ( K e
A second clock signal having 2 or more integer) times the period
Is generated, and the second clock signal is added to 1 / K d ( K d
Is an integer greater than or equal to 2 ), a first clock signal is generated, a laser emission pattern is generated based on this first clock signal and modulation data, and laser power is switched based on this laser emission pattern. Therefore, it is possible to record the recording data on the optical recording medium while preventing the time variation of the laser light irradiation and the laser power variation.

Since the first clock signal which is synchronized with the modulation data and has a constant duty ratio and which is 1 / Kb (Kb is an integer of 2 or more) times the minimum period of the modulation data having the shortest data length can be generated. The recording data can be recorded by finely controlling the switching of the laser power of the laser light.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of an optical recording device according to the present invention.

FIG. 2 is a diagram showing an operation of generating a light emission clock signal.

FIG. 3 is a diagram showing another operation of generating a light emission clock signal.

FIG. 4 is a diagram showing an operation of the first embodiment.

FIG. 5 is a diagram showing a configuration of a second embodiment of an optical recording device according to the present invention.

FIG. 6 is a diagram showing a configuration of a switch unit.

FIG. 7 is a diagram showing another operation of the optical recording apparatus according to the present invention.

FIG. 8 is a diagram showing an operation of a conventional optical recording device.

FIG. 9 is a diagram showing an operation of a pulse train recording system.

[Explanation of symbols]

10 ... Optical disk, 11 ... Disk controller, 12 ... Phase comparison section, 13 ... Voltage controlled oscillation section, 14 ... Frequency division section, 15 ... Mark length determination section, 1
6 ... Emission pattern output unit 21, 22, 23, 6
1, 62, 63 ... Reference signal holding unit, 31, 32, 3
3, 71, 72, 73 ... Switch section, 41 ... Addition section, 42, 92 ... Drive signal generation section, 45 ... Laser diode, 46 ... Photo diode, 60 ...
・ Microcomputers, 81, 82, 83, 85
・ Constant current source

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G11B ^7/ 00-7/013 G11B ^7/ 12-7/22

Claims (8)

(57) [Claims] 1. A laser irradiating means for irradiating an optical recording medium with a laser beam, and a data length determined based on recorded data,
It must be K a ( K a is an integer of 2 or more ) times the data length of the recorded data.
The modulation means for modulating the modulated data and the most data of the modulated data synchronized with the modulated data.
1 / K b ( K b is an integer of 2 or more for a short data period)
Generating a reference clock signal having a number) times the period
The reference signal based on the reference clock signal.
1 / K e ( K e is an integer of 2 or more ) times the frequency of the clock signal
A second clock signal having a period of
A lock signal 1 / K d (K d is an integer of 2 or more) component in the circumferential, third
Clock signal generating means for generating one clock signal, and the above-mentioned modulation data and the first clock signal based on the above-mentioned modulated data.
A laser for generating a laser emission pattern of the laser irradiation means.
The light emission pattern generating means and the laser irradiation hand based on the laser light emission pattern.
The stage is driven, and the modulation data is applied by the laser irradiation means.
An optical recording device, comprising: a control unit that forms a recording mark corresponding to a recording medium on the optical recording medium. 2. The clock signal generating means is the second signal generator .
An oscillation means for generating a clock signal is provided, the phase of the output of the frequency division means for dividing and outputting the second clock signal is compared with the phase of the modulated data, and the oscillation means is controlled based on the comparison result. The optical recording device according to claim 1, further comprising a phase comparison unit. 3. The optical recording apparatus according to claim 1, wherein the control means performs switching control of a power level for driving the laser irradiation means based on the laser emission pattern. . 4. The control means, based on the laser emission pattern, sets a power level for driving the laser irradiation means to a first level equal to a level during reproduction and a second level higher than the first level. The optical recording apparatus according to claim 3, wherein switching control is performed between a level, a third level higher than the second level, and a zero level. 5. The optical recording apparatus according to claim 1, wherein the clock signal generating means generates a clock signal having a duty ratio of 50% as the first clock signal. 6. The optical recording apparatus according to claim 1, wherein the modulating means generates the modulated data by modulating the recording data by a pulse width modulation method. 7. The optical recording according to claim 2, wherein Kb and Kd are 2 and the minimum pattern length of the laser emission pattern is 1/2 of the cycle of the first clock signal. apparatus. 8. Data determined based on recorded data
And the data length K a ( K a is 2 or more
Modulates to the modulation data that is ( upper integer ) times, synchronizes with the above modulation data, and outputs the most data of the above modulation data.
1 / K b ( K b is an integer of 2 or more for a short data period)
Generating a reference clock signal having a number) times the period
The reference signal based on the reference clock signal.
1 / K e ( K e is an integer of 2 or more ) times the frequency of the clock signal
A second clock signal having a period of
A lock signal 1 / K d (K d is an integer of 2 or more) first and division
Laser light emission pattern that generates a clock signal of and synchronizes with the first clock signal
To generate the modulated data based on the laser emission pattern.
A method of recording a recording mark, comprising forming a corresponding recording mark on the optical recording medium .