JP2001056954A - Optical information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the recording operation by accurately controlling the peak power and space power even though the detecting band of the emitted light quantity of a semiconductor laser beam source is in the limited range. SOLUTION: By a CPU 1, a level of a bottom level superimposed current outputted from a bottom level current driving device 8 is changed over when the laser power is detected at the time of recording, and made temporarily to the same as the peak level, then the power of the peak level is detected by controlling so that an LD 2 emits by a constant peak level current in the state of non-pulse only during the specified period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical information recording / reproducing apparatus for recording and reproducing information by irradiating a recording medium such as an optical disk with a laser beam from a semiconductor laser light source.

[0002]

2. Description of the Related Art With the spread of multimedia, music C
A read-only medium (recording medium) such as a D-ROM, a CD-ROM, and recently a DVD-ROM and an information reproducing apparatus have been put to practical use.

Recently, phase-change media have been attracting attention in addition to write-once optical disks using dye media and rewritable MO disks using magneto-optical (MO) media. Optical information recording / reproducing devices have been put to practical use.

A typical recording waveform for recording information on the dye-type medium is, for example, a single-pulse semiconductor laser emission waveform generated based on an 8-16 modulation code or the like. In the single pulse recording, there is a problem that the recording mark is distorted like tears due to the heat of the animal.

Therefore, as a laser diode (LD) emission waveform rule (strategy) for recording information on a dye-based medium, as shown in FIG. 3 (e), a multi-layer based on recording data such as an EFM modulation code is used. There has been proposed a method of forming a mark on a dye-based medium using a pulsed laser beam.

A method has been proposed in which a mark portion formed by the laser light having the multi-pulse waveform includes a head heating pulse and a plurality of successive heating pulses that follow.

When recording on a dye-based medium or a phase-change medium, it is necessary to properly control the recording light emission power. Since the “drive current-emission power characteristic” of the LD easily fluctuates due to self-heating or the like, automatic power control (Automatic Power C) is generally used as a means for stabilizing the emission power.
control (APC) is performed.

In the APC, a part of light emitted from an LD is made incident on a photodetector (PD), and an LD drive current is controlled using a monitor current generated in proportion to the LD emission power.

Here, when only information reproduction is considered,
Generally, a high frequency current is superimposed on the LD drive current to suppress noise. However, since the DC drive current is a constant current, A is easily realized by forming a feedback loop of a relatively low band.
A PC can be realized.

On the other hand, when APC is performed at the time of recording, since the recording power changes at a high speed in order to form a mark / space, it is necessary to devise control. For example, in the case of a CD-based or DVD-based disk medium, the difference between the length of a pit and the land of recorded data on the medium (digital sum) is considered.
If a feedback loop of a low band is configured by utilizing the fact that the value (DSV) becomes zero, the recording power can be controlled with a simple configuration as in the case of reproduction. become unable.

Therefore, for example, FIG.
When recording is performed by the strategy shown in FIG. 0C, for example, when recording data of a mark or space having a length of 11T, which is the longest data length, the emission power is sampled / marked at each mark / space. If the hold is performed, the control band may be several MHz even when the disk rotation speed is about 4 ×, and accurate recording power can be controlled with a relatively inexpensive configuration.

However, in the case of a DVD-based disk medium, it is desirable to perform the above-described multi-pulse emission for both the dye-based / phase-changed systems. Requires a high-speed control band, which is not practical.

As a solution to such a problem,
In the technique described in Japanese Patent Application Laid-Open No. 9-171631,
By providing a period in which the LD emission waveform is appropriately driven in a non-pulse state, an amorphization level (peak power) and a read level (bottom power) are recorded during recording on the phase change medium.
Is controlling.

When the technique described in Japanese Patent Application Laid-Open No. Hei 9-171631 is applied to mark recording power control of a recording strategy of a dye-based medium as shown in FIG. 3E, recording is performed in a non-pulse state. Although the recording mark is not formed well due to continuous heating and becomes a defective portion, the APC operation is performed at relatively long intervals, so that the error correction function hardly affects the reproduction.

Further, since the space recording power is generally a constant power, it is necessary to control the space recording power without losing the recording data by sampling / holding when recording relatively long space data. Can be. Therefore, the space recording power control interval can be controlled at a shorter interval than the mark recording power control interval.

[0016]

However, in the control using the technique described in Japanese Patent Application Laid-Open No. Hei 9-171631, the peak power and the space power can be detected accurately, but the LD emission waveform is generated. When the control device that generates the light emission waveform can generate only a light emission waveform based on the normal 8-16 modulation rule, it is not possible to perform irregular light emission such as temporarily setting the peak level to a non-pulse state.

Further, there is a problem that a great cost is required to add such a function to perform irregular light emission to such an LD light emission waveform control device.

The present invention has been made to solve the above problems, and accurately controls peak power and space power even when the detection band of the amount of emitted light from a semiconductor laser light source is in a limited range. The purpose is to be able to record.

[0019]

According to the present invention, a laser beam emitted from a semiconductor laser light source is emitted onto a recording medium by a positive integer multiple of a channel clock cycle based on a predetermined recording modulation method. An optical information recording / reproducing apparatus that forms a mark or space on the recording medium by causing the semiconductor laser light source to emit pulse light according to a predetermined emission rule when recording information having a data length of Bias level current applying means for applying a level current, bottom level current superimposing means for switching and superimposing a plurality of bottom level currents on the bias level current, and space level current superimposing on a space level current on the bias level current Means and a peak level for superimposing a peak level current on the bias level current Current superimposing means, when detecting the laser power of the semiconductor laser light source at the time of recording on the recording medium, switching the level of the bottom level current superimposed by the bottom level current superimposing means to be temporarily the same as the peak level current. And means for controlling the semiconductor laser light source to emit light in a non-pulse state while keeping the peak level current constant for a predetermined period.

When recording information having a data length of a positive integer multiple of a channel clock cycle based on a predetermined recording modulation method by emitting a laser beam from a semiconductor laser light source onto a recording medium, An optical information recording / reproducing apparatus which forms a mark or space on the recording medium by causing a pulse emission according to a predetermined light emission rule to apply a bias level current to the semiconductor laser light source; Space level current superimposing means for switching and superimposing a plurality of space level currents on the current, peak level current superimposing means for superimposing a peak level current on the bias level current, and the semiconductor laser light source at the time of recording on the recording medium When the laser power is detected, the space level current superimposing means is used. Means for temporarily switching the level of the space level current to be superimposed to the same level as the peak level current and controlling the semiconductor laser light source to emit light in a non-pulse state while keeping the peak level current constant for a predetermined period. Should be provided.

Further, in the optical information recording / reproducing apparatus as described above, the power of the peak level current detected when the semiconductor laser light source emits light in a non-pulse state while the peak level current is kept constant for a predetermined period. Means may be provided for calculating the differential efficiency of the semiconductor laser light source based on the power of the space level current detected when the semiconductor laser light source emits light by the space level current.

Further, in the optical information recording / reproducing apparatus as described above, it is preferable to provide a means for setting the predetermined period so that the recording information is a mark information output period having a predetermined length or more.

In the optical information recording / reproducing apparatus according to the first aspect of the present invention, when detecting the laser power at the time of recording, the bottom level current superimposing means is switched to emit light at the same level as the peak level. Emit light in a non-pulse state for a predetermined period, and detect peak level power.

Further, in the optical information recording / reproducing apparatus according to the second aspect of the present invention, the space level current superimposing means is switched to emit light at the same level as the peak level, so that the peak level remains in a non-pulse state for a predetermined period. Light is emitted, and peak level power is detected.

Further, the optical information recording / reproducing apparatus according to a third aspect of the present invention includes a peak level power detected by emitting a peak level in a non-pulse state for a predetermined period;
The differential efficiency of the laser is calculated based on the space level power detected during the space level emission.

Further, in the optical information recording / reproducing apparatus according to a fourth aspect of the present invention, in order to emit light in a non-pulse state at the peak level, the recording information is not transmitted during the predetermined period when the bottom level or the space level is the same as the peak level. The mark information output period is longer than a predetermined length.

[0027]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a functional block diagram of an optical information recording / reproducing apparatus according to one embodiment of the present invention.

This optical information recording / reproducing apparatus employs an information recording system for recording code data in DVD format on an optical disk of a dye-based medium, and a mark edge (PWM: Pulse Width Mo) using an 8-16 modulation code.
A data modulation method for performing recording is adopted. A semiconductor laser light source emits multi-pulse light, irradiates the optical disk with an optical pulse, and records information by forming a recording mark in the recording area.

That is, the optical information recording / reproducing apparatus emits laser light from a semiconductor laser light source onto a recording medium and records information having a data length of a positive integer multiple of a channel clock cycle based on a predetermined recording modulation method. This is an apparatus that forms a mark or space on a recording medium by causing a semiconductor laser light source to emit pulse light according to a predetermined light emission rule.

In this optical information recording / reproducing apparatus, when normal information recording is performed, peak power (Pw) / bottom power (Pb) for forming a mark by multi-pulses, and space power (Pw) for forming a space. Ps) requires three types of recording power. Its bottom power (P
Since b) and the space power (Ps) may be substantially the same power, control is generally performed with two types of power.

However, since the space power requires power detection, it needs to be at least a certain level. On the other hand, the lower the bottom power, the better the reproduction jitter tends to be. Therefore, in this optical information recording / reproducing apparatus, the bottom power (Pb) and the space power (Pb)
s) are individually controlled.

First, a normal APC operation at the time of recording in the optical information recording / reproducing apparatus will be described. CP
U1 outputs a normal bottom level control signal 104, a space level control signal 106, and a peak level control signal 107 to the bottom level current driver 8, the space level current source 9, and the peak level current source 10, respectively. To set the output current of each device and current source.

The space level current source 9 and the peak level current source 10 are specifically DACs, and the space level current source 9 is an analog signal based on LD drive current information digitally set by the CPU 1. The space level superimposed current 109 is transferred to the peak level current source 10
Output a peak level superimposed current 110, respectively.

The bottom-level current driving device 8 outputs a bottom-level superimposed current 108 by a configuration described later.
The LD driving device 4 supplies a current equal to or larger than an oscillation threshold to a laser diode (LD) 2 which is a semiconductor laser light source. For that purpose, the CPU 1 controls the bias current source 12 by outputting a bias current control signal 120 to the bias current source 12, and the bias current source 12 supplies a bias current 121 to the LD driving device 4 for outputting a current equal to or higher than the oscillation threshold. I do.

In the LD driving device 4, the bottom level superimposed current 108, the space level superimposed current 109, and the peak level superimposed current 110 are superimposed on the bias current 121, and the bottom power (Pb ), Space power (Ps), and peak power (Pw).

The LD emission waveform control device 11 converts the information to be recorded into an 8-16 modulated signal having the waveform shown in FIG. 3B, and further converts the multi-pulse optical waveform shown in FIG. And a bottom power enable signal 101, a space power enable signal 102,
And the peak power enable signal 103 to the LD driving device 4.

When the bottom power enable signal 101, the space power enable signal 102, and the peak power enable signal 103 are at a high level (H level), the LD drive device 4
8, the space level superimposed current 109 and the peak level superimposed current 110 are appropriately superimposed on the bias current 121 and the LD2
To supply the drive current.

When light is emitted at the space level, the space power enable signal 1 is output as shown in FIG.
02 also attains a high level at the same time, and the LD driving device 4 superimposes the space level superimposed current 109 on the bias current 121 and outputs it as a drive current for the LD 2.

When light is emitted at the peak level, as shown in FIG. 3D, the peak power enable signal 103 is set to the high level, and the LD driving device 4 superimposes the peak level superimposed current 110 on the bias current 121. And LD
2 as the driving current.

Further, when light is emitted at the bottom level,
As shown in FIG. 3B, the bottom power enable signal 101 is set to the high level, and the LD driving device 4 superimposes the bottom-level superimposed current 108 on the bias current 121 to make the L level.
It is output as a drive current for D2.

When a drive current is supplied from the LD driving device 4 to the LD 2, the LD 2 emits a laser beam, irradiates an optical disk (not shown), forms a recording mark on the optical disk, and records information. Perform recording and playback.

At the time of recording / reproducing, a part of the light emitted from the LD 2 enters the monitor PD 3, and a monitor PD output current 112 proportional to the emission power from the monitor PD 3 is I / O.
It is output to the V conversion circuit 5. Then, the I / V conversion circuit 5
APC is performed by using the power monitor signal 113 converted by “current-voltage”.

As shown in FIGS. 3F to 3H, the power monitor signal 113 is such that the sample timing signal 111 output from the CPU 1 at the time of outputting long space data (for example, 14T space data) is at a high level. Sample / hold circuit 6
The signal is held, digitized by the A / D converter 7, and output to the CPU 1 as a space power sample signal 114.

The CPU 1 compares the space power sample signal 114 with a reference value and corrects the value of the space level control signal 106 so that the space power (Ps) becomes an appropriate value. Further, the bottom power (Pb) and the peak power (Pw) are determined by the corrected space power (P
s) and the differential efficiency η to calculate and correct the superimposed current.

As shown in the diagram of FIG. 5, the differential efficiency η is represented by the slope of the straight line of the “LD drive current-LD emission power” characteristic: LD emission power difference (ΔP) / LD drive current difference (ΔI ).

Here, the LD corresponding to the bottom power (Pb), the space power (Ps), and the peak power (Pw).
Assuming that drive currents are Ib, Is, and Iw, respectively, the bottom power (Pb) and the peak power (Pw) can be expressed by the following relational expressions (1) and (2).

[0047]

Pb = Ps−η × (Is−Ib) (1) Pw = Ps + η × (Iw−Is) (2)

Based on the relational expressions (1) and (2), the bottom level driving current (Ib) and the peak level driving current (Iw) are calculated by the following relational expressions (3) and (4). Can be calculated.

[0049]

Ib = Is− (Ps−Pb) / η (3) Iw = Is + (Pw−Ps) / η (4)

In the CPU 1, as described above, the bottom level driving current (Ib) and the peak level driving current (Iw)
To control the bottom-level current driving device 8 and the peak-level current source 10, respectively.

As described above, since the bottom level, space level, and peak level LD drive currents are obtained by adding current to the bias current 121, the bias current 121 is set to “Ibias” and the bottom level superimposed current 10
8 is “ΔIb” and the space level superimposed current 109 is “ΔIb”.
Assuming that “Is” and the peak level superimposed current 110 are “ΔIw”, the bottom level driving current, the space level driving current, and the peak level driving current are expressed by the following equations (5) to (7), respectively. Can be.

[0052]

Ib = Ibias + ΔIb (5) Is = Ibias + ΔIs (6) Iw = Ibias + ΔIw (7)

Here, the time interval at which the normal APC is performed is set to be relatively shorter than the time interval of the differential efficiency calculation sequence described later. For example, when a 14T space, which is the longest data length of the 8-16 recording modulation system, is output, the space level is sampled.

Further, since the 14T data length is a SYNC code in the DVD standard, when the space power sampling period is set to output 14T space data, the SY code is used.
Sampling / holding is performed almost every two times of the NC frame (1488T).

The 14T data has a 14T mark or 1 according to a predetermined rule in order to make the DSV zero.
Since 4T space is selected, it is not necessarily 1 for 2SYNC
Although a 14T space is not output every time, in this embodiment, for convenience, it is assumed that a 14T mark and a 14T space appear alternately.

In this way, by calculating the power of the bottom level and the power of the peak level based on the space level sampled at the time of outputting the long space data and the differential efficiency η obtained in advance, even in the circuit configuration of the low band, the power of each level is obtained. Power correction can be performed.

Next, as shown by the diagram in FIG. 6, if the differential efficiency η fluctuates during the recording operation, an error occurs in the calculation of Ib and Iw, and the correction of the bottom power and the peak power is accurately performed. I can't do it.

As a method of recalculating the differential efficiency η during this recording, there is a method of sampling power at two points, that is, a space level and a peak level, as in the technique described in JP-A-9-171631 described above. However, in this method, it is necessary to add to the LD light emission waveform control device 11 a function of performing irregular light emission such as temporarily setting a non-pulse state.

Therefore, the optical information recording / reproducing apparatus of this embodiment is configured so that the bottom level can be switched to a plurality of levels as appropriate, and the bottom level is temporarily set to the same level as the peak level so that the peak level becomes non-pulsed. Control to be in a state. As a result of the control, the peak level can be sampled and held, and the differential efficiency η can be calculated.

That is, the CPU 1, the LD driving device 4, the bias current 121, and the like function as a bias level current applying means for applying a bias level current to the semiconductor laser light source. CPU 1, LD drive device 4,
The bottom-level current driver 8 and the like perform the function of a bottom-level current superimposing unit that switches and superimposes a plurality of levels of bottom-level current on the bias level current.

The CPU 1, the LD driving device 4, the space level current source 9, etc. function as a space level current superimposing means for superimposing the space level current on the bias level current. The CPU 1, the LD driving device 4, the peak level current source 10 and the like function as a peak level current superimposing means for superimposing the peak level current on the bias level current.

When the CPU 1 or the like detects the laser power of the semiconductor laser light source during recording on the recording medium,
The level of the bottom level current to be superimposed by the bottom level current superimposing means is switched to be temporarily the same as the peak level current, and the peak level current is kept constant for a predetermined period so that the semiconductor laser light source emits light in a non-pulse state. Acts as a means to do.

Further, the CPU 1 or the like controls the semiconductor laser light source based on the power of the peak level current detected when the semiconductor laser light source emits light in a non-pulse state while keeping the peak level current constant for a predetermined period, and the space level current. It functions as means for calculating the differential efficiency of the semiconductor laser light source based on the power of the space level current detected when the light is emitted.

Further, the CPU 1 or the like sets the predetermined period
It also functions as a means for setting the recording information so as to be a mark information output period of a predetermined length or more.

The differential efficiency calculation sequence according to the present invention in the optical information recording / reproducing apparatus will be described below with reference to FIGS. 2 and 4. Bottom level current driver 8
Is composed of two D / A converters 802 and 803 and a switch 804 as shown in FIG. Then, the DAC selected by the switch 804 outputs a bottom-level superimposed current.

The DAC 802 uses the normal bottom level control signal 104 to change the bottom level to the normal bottom level (P
When the light emission during normal recording is performed, the switch 804 is set to the high (H) side by the bottom level switching signal 115.

The CPU 1 starts the differential efficiency calculation sequence at a lower frequency than the normal APC interval (the frequency is determined by the temporal variation of the differential efficiency η of the LD 2,
It should be determined experimentally).

First, the CPU 1 uses the bottom level control signal 105 at the time of η calculation to change the LD 2 to the peak power (Pw).
The DAC 803 is set to emit light at the level (see (2) of the state transition in FIG. 4).

In the sequence state, 1
When the 4T mark data is output, the CPU 1 sets the bottom level switching signal 115 to low (L) so that the bottom level superimposed current is output from the DAC 803, and at the same time, sets the sample timing signal 111 to high (H). ).

Then, since the bottom level and the peak level temporarily become the same level, the LD 2 emits light at a constant peak level (in a non-pulse state) only for the 14T period. This level of power is sampled by the sample and hold circuit 6 and output to the CPU 1, but the CPU 1
A sample value is obtained separately from the space level sampled at the time of C.

After outputting the 14T mark data, the CPU 1
Since the bottom level switching signal 115 is immediately returned to high (H), the subsequent bottom level emission returns to the normal bottom level (Pb) (see (3) in the state transition in FIG. 4).

As described above, a portion recorded in a non-pulse state is a defective portion because a recording mark is not formed well by continuous heating, but becomes a non-pulse state only at the time of outputting 14T mark data. If this sequence is performed at relatively long intervals, the error correction function hardly affects the reproduction.

Based on the peak level power (Pw) thus obtained, the space level power (Ps) sampled during the normal APC operation, and the respective LD drive currents Is and Iw, the CPU 1 calculates The differential efficiency η is calculated by the relational expression (8) shown in FIG.

[0074]

Η = (Pw−Ps) / (Iw−Is) (8)

As described above, the optical information recording / reproducing apparatus of this embodiment switches the bottom level current superimposing means to emit light at the same level as the peak level when detecting the laser power at the time of recording. ,
Since the peak level is controlled to emit light in a non-pulse state for a predetermined period and the power of the peak level is detected based on the control, a regular LD based on the 8-16 modulation rule is used.
Even when an LD emission waveform control device that can output only an emission waveform is used, irregular LD emission can be performed temporarily, and even if an output light amount detector with a limited detection band is used, the peak power can be accurately determined. Recording can be performed by controlling the space power.

The differential efficiency of the laser is calculated based on the peak level power detected by emitting the peak level in a non-pulse state for a predetermined period and the space level power detected at the time of emitting the space level. Can be performed accurately.

Further, since the bottom level or the space level is the same as the peak level in order to emit the peak level in a non-pulse state, the recording information is a mark information output period of a predetermined length or more. The space level can be quickly returned to the normal level, and the influence on the jitter deterioration during reproduction can be prevented.

Next, another embodiment of the present invention will be described. In the optical information recording / reproducing apparatus of the above-described embodiment, the bottom level (Pb) and the space level (Ps) are individually controlled. However, as described above, the bottom level and the space level can be controlled at substantially the same level. is there.

Therefore, in the optical information recording / reproducing apparatus of the next embodiment, the bottom level and the space level are driven by the same current source.

FIG. 7 is a block diagram showing the configuration of an optical information recording / reproducing apparatus according to another embodiment of the present invention, and portions common to FIG. 1 are denoted by the same reference numerals. In this optical information recording / reproducing apparatus, a CPU 1 is a space level current driver 1
The normal space level control signal 1105 and the peak level control signal 1107 are output to the current source 009 and the peak level current source 1010, respectively, to set the output current of the device and the current source.

The LD driver 1004 supplies a current equal to or larger than the oscillation threshold to the LD 2. For this purpose, the CPU 1 controls the bias current source 12 by outputting a bias current control signal 120 to the bias current source 12.
In 004, a bias current 121 for outputting a current equal to or greater than the oscillation threshold is supplied.

In the LD driving apparatus 1004, the space level superimposed current 1109 and the peak level superimposed current 1110 are superimposed on the bias current 121, and the space power (Ps) and the peak power (Ps) are superimposed on the respective superimposed currents. Pw) is determined.

The LD emission waveform control device 1011 converts the information to be recorded into an 8-16 modulation signal having the waveform shown in FIG. 9A, and further converts the multi-pulse optical waveform shown in FIG. 9D. A space power enable signal 1102 and a peak power enable signal 11
03 is supplied to the LD driving device 1004.

When the space power enable signal 1102 and the peak power enable signal 1103 are at the high (H) level, the LD driver 1004 outputs the space level superimposed current 1109 and the peak level superimposed current 1110.
Is appropriately superimposed on the bias current 121 to supply a drive current to the LD 2.

When light is emitted at the space level / bottom level, as shown in FIG. 9B, the space power enable signal 1102 becomes high (H), and the LD driving device 1004 biases the space level superimposed current 1109. The current is superimposed on the current 121 and output as a drive current for the LD2.

When light is emitted at the peak level, as shown in FIG. 9C, the peak power enable signal 1103 is set to high (H), and the LD driving device 1004 changes the peak level superimposed current 1110 to the bias current 121. And output as a drive current of LD2.

That is, the CPU 1, the bias current source 12, the LD driving device 1004, and the like function as a bias level current applying means for applying a bias level current to the semiconductor laser light source.

The CPU 1, the LD driving device 1004, the space level current driving device 1009, and the like function as a space level current superimposing means for switching and superimposing a plurality of space level currents on the bias level current.

The CPU 1, the LD driving device 1004, the peak level current source 1010 and the like function as a peak level current superimposing means for superimposing the peak level current on the bias level current.

When the CPU 1 or the like detects the laser power of the semiconductor laser light source at the time of recording on the recording medium, it switches the level of the space level current to be superimposed by the space level current superimposing means to temporarily have the same level as the peak level current. And functions as a means for controlling the semiconductor laser light source to emit light in a non-pulse state while keeping the peak level current constant for a predetermined period.

Further, the CPU 1 or the like controls the semiconductor laser light source based on the power of the peak level current detected when the semiconductor laser light source emits light in a non-pulse state while keeping the peak level current constant for a predetermined period, and the space level current. It functions as means for calculating the differential efficiency of the semiconductor laser light source based on the power of the space level current detected when the light is emitted.

Further, the CPU 1 etc.
It also functions as a means for setting the recording information so as to be a mark information output period of a predetermined length or more.

Next, a differential efficiency calculation sequence according to the present invention in the optical information recording / reproducing apparatus will be described. The space level current driver 1009 is composed of two D / A converters 1902 and 1903 and a switch 1904 as shown in FIG. Then, the DAC selected by the switch 1904 outputs a space level superimposed current 1109.

The DAC 1902 is set by the normal space level control signal 1105 so that the space level becomes the normal space level (Ps). When light emission during normal recording is performed, the switch 1904 is set by the space level switching signal 1115. Is set to the high (H) side.

When the differential efficiency sequence is started, the CPU 1 firstly sets the η-calculating space level control signal 11
According to 06, the DAC 1903 is set so that the LD 2 emits light at the level of the peak power (Pw).

In the sequence state, 1
When the 4T mark data is output, the CPU 1 sets the space level switching signal 1115 to low (L) so that the superimposed current of the space level is output from the DAC 1903, and at the same time, sets the sample timing signal 111 to high ( H).

Then, since the space level and the peak level temporarily become the same level, the LD 2 emits light at a constant peak level (in a non-pulse state) only during the 14T period. This level of power is sampled by the sample and hold circuit 6 and output to the CPU 1.

In the optical information recording / reproducing apparatus of this embodiment,
Since the light emission level is only the space level / peak level, the peak (level) power (P
w) and the space (level) power (Ps) detected during the normal APC operation enables accurate power control.

Then, similarly to the optical information recording / reproducing apparatus of the above-described embodiment, the differential efficiency η can be calculated by using the relational expression of (8) shown in Expression 4. By using the calculated differential efficiency η, the bias current 121
Can also be configured to correct.

As described above, the optical information recording / reproducing apparatus of this embodiment switches the space level current superimposing means to emit light at the same level as the peak level, so that the peak level remains in the non-pulse state for a predetermined period. Since the light is controlled to emit light and the peak level power is detected based on the control, even when an LD light emission waveform control device that can output only a regular LD light emission waveform based on the 8-16 modulation rule is used, it is temporarily disabled. LD light emission can be performed irregularly, and recording can be performed by accurately controlling the peak power and the space power even when using an emission light amount detector having a limited detection band.

[0101]

As described above, according to the optical information recording / reproducing apparatus of the present invention, the peak power and the space power can be accurately adjusted even when the detection band of the amount of light emitted from the semiconductor laser light source is limited. It can be controlled to record.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an optical information recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a bottom level current driver 8 of the optical information recording / reproducing apparatus shown in FIG.

FIG. 3 is a waveform diagram showing signals output from respective units during reproduction, normal recording, and differential efficiency calculation of the optical information recording / reproducing apparatus shown in FIG.

FIG. 4 is a waveform diagram showing signals output from respective units during a differential efficiency calculation sequence of the optical information recording / reproducing apparatus shown in FIG.

FIG. 5 is an LD in the optical information recording / reproducing apparatus shown in FIG.
FIG. 3 is a diagram illustrating a relationship between a driving current and an LD emission power.

FIG. 6 shows an LD drive current −L when the differential efficiency η fluctuates during the recording operation in the optical information recording / reproducing apparatus shown in FIG.
FIG. 4 is a diagram illustrating a relationship between D light emission powers.

FIG. 7 is a block diagram showing a configuration of an optical information recording / reproducing apparatus according to another embodiment of the present invention.

8 is a block diagram showing an internal configuration of a space level current driver 1009 of the optical information recording / reproducing device shown in FIG.

9 is a waveform diagram showing signals output from the respective units during reproduction, normal recording, and differential efficiency calculation of the optical information recording / reproducing apparatus shown in FIG.

FIG. 10 is a diagram illustrating an example of a channel clock, recording data, and an LD emission waveform when data is recorded on a recording medium.

[Explanation of symbols]

1: CPU 2: Laser diode (LD) 3: Monitor PD 4, 1004: LD drive device 5: I / V conversion circuit 6: Sample hold circuit 7: A / D converter 8: Bottom level current drive device 9: Space level Current source 10, 1010: Peak level current source 11, 1011: LD emission waveform control device 12: Bias current source 802, 803, 1902, 1903: D / A converter (DAC) 804, 1904: Switch 1009: Space level current drive Device 101: Bottom power enable signal 102, 1102: Space power enable signal 103, 1103: Peak power enable signal 104: Normal bottom level control signal 105: Bottom level control signal at the time of η calculation 106: Space level control signal 107, 1107: Peak Bell control signal 108: Bottom level superimposed current 109, 1109: Space level superimposed current 110, 1110: Peak level superimposed current 111: Sample timing signal 112: Monitor PD output current 113: Power monitor signal 114: Space power sample signal 115: Bottom Level switching signal 120: Bias current control signal 121: Bias current 1105: Normal space level control signal 1106: Space level control signal when calculating η 1115: Space level switching signal

Claims (4)

[Claims] 1. A semiconductor laser light source which emits laser light from a semiconductor laser light source onto a recording medium and records information having a data length of a positive integer multiple of a channel clock cycle based on a predetermined recording modulation method. An optical information recording / reproducing apparatus which forms a mark or a space on the recording medium by causing a pulse emission according to a predetermined light emission rule to generate a bias level current; Bottom level current superimposing means for superimposing and superimposing a plurality of levels of bottom level current on the current; space level current superimposing means for superposing a space level current on the bias level current; and a peak for superimposing a peak level current on the bias level current. Level current superimposing means; and before recording on the recording medium. Upon detection of the laser power of the semiconductor laser light source, to temporarily the peak level current at the same level by switching the level of the bottom level current to be superimposed by the bottom level current superposition means,
Means for controlling the semiconductor laser light source to emit light in a non-pulse state by keeping the peak level current constant for a predetermined period of time. 2. A semiconductor laser light source for emitting laser light from a semiconductor laser light source onto a recording medium and recording information having a data length of a positive integer multiple of a channel clock cycle based on a predetermined recording modulation method. An optical information recording / reproducing apparatus that forms a mark or space on the recording medium by causing a pulse emission according to a predetermined light emission rule to form a mark or space, wherein: a bias level current application unit that applies a bias level current to the semiconductor laser light source; Space level current superimposing means for switching and superimposing a plurality of space level currents on a current; peak level current superimposing means for superimposing a peak level current on the bias level current; and the semiconductor laser light source during recording on the recording medium When the laser power is detected, the space level current superimposing means is used. Means for switching the level of the space level current to be superimposed to temporarily make it the same level as the peak level current, and controlling the semiconductor laser light source to emit light in a non-pulse state while keeping the peak level current constant for a predetermined period. An optical information recording / reproducing device provided. 3. The optical information recording / reproducing apparatus according to claim 1, wherein the peak level current is kept constant for a predetermined period and the peak level current detected when the semiconductor laser light source emits light in a non-pulse state. And a means for calculating the differential efficiency of the semiconductor laser light source based on the power of the laser light source and the power of the space level current detected when the semiconductor laser light source emits light by the space level current. Information recording and playback device. 4. The optical information recording / reproducing apparatus according to claim 1, further comprising means for setting the predetermined period so that the recording information is a mark information output period of a predetermined length or more. An optical information recording / reproducing apparatus characterized in that: