JP2001043551A - Optical information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the circuit constitution which is formed for lowering the noise caused by a turn-back light from a recording medium. SOLUTION: When the information recorded on an optical disk 6 is reproduced by a controller 10, etc., a signal with the frequency higher than the channel clock period based on the specific recording modulation system is generated, and a driving current for reproduction, to which the high frequency component is added by superposing the high frequency signal to the driving DC current of an LD light source 2, is produced. When the information is recorded on the optical disk 6, the recording operation is executed in such a manner that a light emitting pulse according to the specific light emitting regulation is formed by using the channel clock period and the high frequency signal generated like the above mentioned manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus such as an optical disk drive for recording and reproducing information by irradiating a recording medium which is an optical disk such as a CD with a laser beam from a light source.

[0002]

2. Description of the Related Art With the spread of multimedia, music C
2. Description of the Related Art Read-only media (recording media) such as D, CD-ROM, and recently DVD-ROM, and information reproducing apparatuses have been put to practical use. Recently, phase-change media as well as write-once optical disks using dye-based media and rewritable MO disks using magneto-optical (MO) media have been attracting attention. Recording and reproducing devices have been put to practical use. In addition, rewritable DVD media has attracted much attention as next-generation multimedia recording media and large-capacity storage media.

[0003] As a general recording waveform for recording information on a dye-based medium, an 8 as shown in FIG.
Like a -16 modulation signal, a single-pulse semiconductor laser (L) generated based on the recording modulation method of an 8-16 modulation code
D) There is a light emission waveform, but in single pulse recording using this recording waveform, there is a problem that the recording mark is distorted like tears due to heat generation.

For this reason, the LD emission waveform rule (strategy) for recording information on a dye-based medium is shown in FIG.
A method has been proposed in which a mark is formed on a dye-based medium by using a laser light having a multi-pulse waveform as shown in an optical waveform shown in FIG. There has been proposed a system in which the mark portion of the multi-pulse waveform is configured by a head heating pulse and a plurality of subsequent continuous heating pulses.

Further, as a general recording waveform for recording information on a phase change type medium, as shown in an optical waveform of FIG. A multi-pulse waveform has been proposed that includes a leading heating pulse for preheating, a plurality of successive heating pulse trains following the heating pulse, and a continuous cooling pulse train therebetween.

For each of such pulses, it is necessary to set an optimum pulse width with high precision, particularly in the case of a high recording density medium such as a DVD. In addition, the type of the medium, the recording linear velocity, and the current recording By setting the optimum value in accordance with conditions such as the space length immediately before the mark, it is possible to reduce the reproduction jitter, improve the power margin, and improve the overwrite characteristics (in the case of a phase change type medium).

As a conventional technique for adjusting the pulse width to perform optimum recording, a method of finely adjusting the pulse width using, for example, a delay element has been proposed. This method has a problem that the delay time is not stable due to delay variation of the delay element and the like, and as a means for solving this problem, a technique of correcting a pulse width using a clock obtained by multiplying a channel clock has been proposed. .

For example, in the technique disclosed in Japanese Patent No. 2713670, when a space length immediately before is short using a clock obtained by multiplying a reference clock, the leading pulse is shortened.
The tip of the recording mark is not affected by the heat of the immediately preceding recording mark. In the case where the pulse width is adjusted with high accuracy by this technique, if the frequency of the clock to be multiplied is low, the resolution of the pulse width adjustment is reduced, and the effect of reducing the reproduction jitter and the like becomes difficult to appear.

For example, when recording is performed under optimal conditions for DVD-R media, it is necessary to adjust the pulse width with an accuracy of at least 1/20 of one channel clock. Even if the correction is performed using both edges of the multiplied clock, the channel clock of the DVD is set to 26 MHz,
The multiplied clock becomes 260 MHz, and in the related art, E
CL (Emitter Coupled Logic)
It was almost impossible without using an ultra-high-speed device such as this.

However, with the recent rapid development of LSI technology, CMOS (Complementary Me
It has become possible to operate at a frequency of 500 MHz or more in a chip even with the use of a tal-oxide-semiconductor element, and it has become possible to correct the pulse width with high accuracy using a high-speed clock. .

When information is recorded / reproduced by irradiating a recording medium with a laser beam, reflected light from the recording medium returns to the LD and becomes noise (return light noise). For this reason, various optical devices have been devised so that the emitted light does not return to the LD light source, but return light is generated to a small extent.

In order to reduce this return light noise, a DC current source for driving the LD is usually 200 to 500 MHz.
In general, an LD is made to emit light by superimposing a high frequency signal of z.

As a means for superimposing a high-frequency signal, it is general to superimpose a high-frequency signal generated by an oscillation circuit by AC-coupling, but as disclosed in JP-A-6-204617. Means for superimposing a high-speed rectangular wave have also been proposed.

As described above, since a high-frequency signal is generally superimposed on a DC current source by AC coupling, the peak current when superimposed is naturally larger than when no superimposition is performed. When a high frequency signal is superimposed, the rated current may be exceeded and the LD may be destroyed. Therefore, high frequency superposition is not generally performed at the time of recording power output. As described above, a high-speed clock can be used as a means for correcting a recording pulse with high accuracy.

On the other hand, a signal to be superimposed to reduce noise during reproduction also requires a high frequency. Conventionally, a high-frequency generation circuit at the time of reproduction has often been an oscillation circuit using an inductor and a capacitor. However, a high-frequency signal can be digitally superimposed using a high-speed clock, similarly to the recording pulse correction. .

[0016]

However, in the prior art as described above, the recording pulse generating means at the time of recording and the high-frequency signal generating means at the time of reproduction are considered as completely separate modules. Since the oscillator circuit is provided, there is a problem that the circuit configuration becomes complicated.

The present invention has been made to solve the above-described problems, and has as its object to simplify a circuit configuration for reducing noise due to return light from a recording medium.

[0018]

According to the present invention, a laser beam is emitted from a semiconductor laser light source onto a recording medium and a positive integer multiple of a channel clock cycle based on a predetermined recording modulation method is attained. When recording information consisting of a pulse having a length, in the optical information recording / reproducing apparatus for forming a mark or space on the recording medium by causing the semiconductor laser light source to emit pulse light according to a predetermined light emission rule, A high-frequency signal generating means for generating a high-frequency signal, and when reproducing information recorded on the recording medium, a high-frequency signal generated by the high-frequency signal generating means is superimposed on a driving direct current of the semiconductor laser light source. To generate a reproduction drive current to which the high frequency component is added, and to record information on the recording medium, the channel clock It is provided with a means for forming a light emitting pulse by the predetermined emission rule by using the period and the high-frequency signal generated by the high frequency generating means.

When recording information consisting of a pulse having a length of a positive integer multiple of a channel clock period 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 light source to emit pulse light according to a predetermined light emission rule,
A high-frequency signal generating means for generating a signal having a frequency higher than the channel clock cycle; and a high-frequency signal generated by the high-frequency signal generating means for driving the semiconductor laser light source when reproducing information recorded on the recording medium. When generating a reproduction drive current to which the high-frequency component is added by superimposing the direct current, and when recording information on the recording medium,
It is preferable to provide a means for forming a light emission pulse according to the predetermined light emission rule by appropriately dividing the frequency of the high frequency signal generated by the high frequency signal generation means.

Further, when recording a laser beam from a semiconductor laser light source onto a recording medium and recording information comprising a pulse having a length that is a positive integer multiple of a channel clock period based on a predetermined recording modulation method, In an optical information recording / reproducing apparatus that forms a mark or space on the recording medium by causing a light source to emit a pulse according to a predetermined light emission rule, a signal having a frequency higher than the channel clock cycle is generated by multiplying the channel clock cycle. High-frequency signal generating means, and when reproducing information recorded on the recording medium, the high-frequency signal generated by the high-frequency signal generating means is superimposed on a driving DC current of the semiconductor laser light source, and the high-frequency component is added. When a drive current for reproduction is generated and information is recorded on the recording medium, the channel clock cycle and the And a high-frequency signal generated by the frequency generation means may be provided with means for forming a light emitting pulse by the predetermined emission rule using.

In the optical information recording / reproducing apparatus as described above, the light emission pulse according to the predetermined light emission rule may be constituted by a pulse train based on a high-frequency signal generated by the high-frequency signal generation means.

Further, in the optical information recording / reproducing apparatus as described above, the predetermined light emission rule when information is recorded on the recording medium is set to be a positive integer multiple of the channel clock period according to the recording modulation method. The rule may be a multi-pulse train that emits a plurality of pulses with respect to the pulse.

In the above-mentioned optical information recording / reproducing apparatus, the multi-pulse train is composed of a head heating pulse and a plurality of succeeding rear heating pulse trains, and the head heating pulse is defined by using the channel clock cycle as a basic clock. Preferably, a basic pulse of the rear heating pulse train is formed, and the basic pulse is corrected based on the high frequency signal to form a light emission pulse according to the predetermined light emission rule.

Further, in the optical information recording / reproducing apparatus as described above, the multi-pulse train includes a head heating pulse, a head cooling pulse, a plurality of subsequent rear heating pulses and a rear cooling pulse, and the channel clock cycle. Is used as a basic clock to form a basic pulse of the first heating pulse and / or the rear heating pulse train and / or the final cooling pulse, and the basic pulse is corrected based on the high frequency signal to form a light emitting pulse according to the predetermined light emitting rule. Good to do.

In the optical information recording / reproducing apparatus as described above, the type of the correction processing based on the high frequency signal of the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse is determined according to the type of the recording medium. It is good to switch.

Further, in the optical information recording / reproducing apparatus as described above, the type of correction processing based on the high frequency signal of the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse is switched according to the recording linear velocity. Good.

Further, in the optical information recording / reproducing apparatus as described above, the type of the correction processing based on the high frequency signal of the head heating pulse may be switched according to the length of the space immediately before the current recording mark.

The optical information recording / reproducing apparatus according to the first aspect of the present invention includes a high-frequency signal generating means for generating a signal having a frequency higher than the channel clock, and reproduces information recorded on the recording medium. When a high-frequency signal generated by the high-frequency signal generating means is superimposed on a direct current for driving the LD so that the reproducing LD driving current has a high-frequency component, and when information is recorded on a recording medium, Using the channel clock and the high-frequency signal generated by the high-frequency generator, a pulse according to a predetermined light emission rule can be formed.

In the optical information recording / reproducing apparatus according to the second aspect of the present invention, when information is recorded on a recording medium, the frequency of the high frequency signal generated by the high frequency signal generating means is appropriately divided to obtain a predetermined value. Can be formed in accordance with the light emission rule.

In the optical information recording / reproducing apparatus according to the third aspect of the present invention, by multiplying the channel clock cycle, a signal having a frequency higher than the channel clock cycle can be generated.

In the optical information recording / reproducing apparatus according to a fourth aspect of the present invention, the pulse according to the predetermined light emission rule is constituted by a pulse train based on a high-frequency signal generated by the high-frequency signal generating means.

In the optical information recording / reproducing apparatus according to the fifth aspect of the present invention, a plurality of predetermined light emission rules for recording information on a recording medium are provided for a pulse of N × T length in a recording modulation system. Is a multi-pulse train that emits the above pulse.

In the optical information recording / reproducing apparatus according to the sixth aspect of the present invention, the multi-pulse train for recording on the recording medium comprises a head heating pulse and a plurality of succeeding rear heating pulse trains. And / or the rear heating pulse train forms a basic pulse using a channel clock as a basic clock, and forms a pulse according to a predetermined light emission rule by correcting the basic pulse with a high-frequency signal.

In the optical information recording / reproducing apparatus according to a seventh aspect of the present invention, a multi-pulse train for recording on a recording medium includes a head heating pulse and a head cooling pulse, and a plurality of subsequent rear heating pulses and a rear cooling pulse. Composed of pulses,
The first heating pulse and / or the rear heating pulse train and / or the last rear cooling pulse (final cooling pulse) form a basic pulse using the channel clock as a basic clock,
A pulse according to a predetermined light emission rule is formed by correcting a basic pulse with a high-frequency signal.

In the optical information recording / reproducing apparatus according to the eighth aspect of the present invention, the method of correcting the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse by the high frequency signal is switched according to the type of the recording medium. It is like that.

In the optical information recording / reproducing apparatus according to the ninth aspect of the present invention, the method of correcting the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse by the high frequency signal is switched according to the recording linear velocity. It was made.

In the optical information recording / reproducing apparatus according to the tenth aspect of the present invention, the method of correcting the head heating pulse by the high frequency signal is switched according to the length of the space immediately before the current recording mark. is there.

[0038]

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

This optical information recording / reproducing apparatus records (appends) DVD format code data on a dye-based medium (for example, a dye-based optical disk) or records it on a phase-change type medium (for example, a phase-change type disk). (Overwrite) information recording / reproducing method is adopted, and a mark edge (PWM: Pulse Width Modul) using an 8-16 modulation code as a data modulation method.
ation) record.

Then, information is recorded using the above-described recording data by causing the semiconductor laser to emit multi-pulses on the optical disk as the medium to form recording marks.

In this optical information recording / reproducing apparatus, first, when information is recorded, 8-16 modulation code data L4 (see FIG. 2 (a)), which is recording data, is transmitted to the recording pulse generating apparatus 11 by the controller 10. When output, the recording pulse generation device 11 generates a recording pulse control signal L1,
The LD drive circuit 1 drives the LD light source 2 to emit multi-pulse light by an LD drive current L2 corresponding to the recording pulse control signal L1, and rotates the optical disk 6 by a spindle motor (not shown) to thereby pick up an optical pickup. The multi-pulse light from the LD light source 2 is applied to the recording layer of the optical disc 6 via the collimating lens 3, the polarizing beam splitter 4, and the objective lens 5 of the optical system, thereby forming a recording mark on the optical disc 6. Record information.
In addition, a part of the light emission pulse is emitted from the polarization beam splitter to the light receiving element 8 via the objective lens 7, amplified by a head amplifier, and output to the controller 10 as a light emission level signal. Based on this signal, the controller 1
0 performs laser power control (APC).

The controller 10 outputs a drive current control signal L5 to the LD drive circuit 1 so as to output an LD drive current for recording power. LD drive circuit 1
Determines the current level of the drive current L2 based on the drive current control signal L5. At this time, the switch 15 is turned off.

In the recording pulse generator 11, the channel clock L3 output from the controller 10 in synchronization with the 8-16 modulation code data L4 is used as a basic pulse (basic wave).
In the recording period shown in FIG. 2B and FIG. 3B, a multi-pulse (a waveform indicated by a solid line in the drawing) is formed. The high-frequency signal generator 12 outputs a high-frequency signal L12 having a frequency sufficiently higher than the channel clock, as shown in FIG. Then, the pulse width of each pulse is finely adjusted using the high-frequency signal L12 according to each recording condition described later.

That is, the controller 10, the recording pulse generator 11, the high-frequency signal generator 12, and the like emit laser light from the semiconductor laser light source onto the recording medium and have a positive channel clock cycle based on a predetermined recording modulation method. Means for forming 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 when recording information consisting of a pulse having a length of an integral multiple,
A high-frequency signal generating means for generating a signal having a frequency higher than the channel clock cycle; and a high-frequency signal generated by the high-frequency signal generating means superimposed on a driving direct current of the semiconductor laser light source when reproducing information recorded on the recording medium. When recording information on a recording medium by generating a reproduction drive current to which a high frequency component is added, a light emission pulse according to a predetermined light emission rule is generated using a channel clock cycle and a high frequency signal generated by the high frequency generation means. It acts as a means of forming.

When recording information on a recording medium,
By appropriately dividing the frequency of the high-frequency signal generated by the high-frequency signal generating means, it also functions as a means for forming a light-emitting pulse according to a predetermined light-emitting rule.

Further, it also functions as a means for forming a light emission pulse according to a predetermined light emission rule from a pulse train based on a high frequency signal generated by the high frequency signal generation means. Further, the predetermined light emission rule when information is recorded on a recording medium is a rule that a multi-pulse train that emits a plurality of pulses for a pulse having a positive integer multiple of a channel clock cycle by a recording modulation method is used. It also serves as a means.

Further, the multi-pulse train is composed of a head heating pulse and a plurality of succeeding rear heating pulse trains,
The head heating pulse and / or the base pulse of the rear heating pulse train are formed using the channel clock cycle as a base clock, and the base pulse is corrected based on a high-frequency signal to form a light emission pulse according to a predetermined light emission rule. .

The multi-pulse train is composed of a head heating pulse and a head cooling pulse, and a plurality of subsequent rear heating pulses and a rear cooling pulse, and the head heating pulse and / or the rear heating pulse train is determined by using a channel clock cycle as a basic clock. And / or constitutes a basic pulse of the final cooling pulse, and also performs a function of correcting the basic pulse based on the high-frequency signal to form a light emission pulse according to a predetermined light emission rule.

Further, it also functions as a means for switching the type of correction processing based on the high-frequency signal of the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse in accordance with the type of recording medium.

The function of a means for switching the type of correction processing based on the high frequency signal of the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse in accordance with the recording linear velocity is also achieved.

Further, a function of a means for switching the type of correction processing based on the high frequency signal of the head heating pulse in accordance with the length of the space immediately before the current recording mark is also performed.

FIG. 2B shows an example of an optical waveform when recording is performed on a phase change type medium. In this case, the pulse width of the first heating pulse, the pulse width of the subsequent heating / cooling multi-pulse train, and the last pulse width are shown. The pulse width of the cooling pulse is corrected by the high-frequency signal L6, and is corrected to the waveform shown by the broken line in the figure.

FIG. 3B shows an example of an optical waveform when recording is performed on a dye-based medium. In this case, the pulse width of the head heating pulse and the pulse width of the subsequent heating multi-pulse train are determined by the high-frequency signal L6. Then, the waveform is corrected to the waveform shown by the broken line in the figure.

At this time, the pulse width is finely adjusted by the high frequency signal L6 output from the high frequency signal generator 12 (see FIG. 14). For example, assuming that the channel clock frequency of the DVD format is 26.16 MHz, in the present embodiment, the frequency of the high-frequency signal L6 is set to the channel clock L
The frequency is set to 260 MHz, which is about 10 times as large as 3.

As shown in FIG. 14, when the recording pulse width is corrected using the rise / fall of the high-frequency signal L6, the resolution of 1/20 of the channel clock (about 0.2 ns) can be obtained. In addition, it is possible to perform correction of a recording pulse necessary for performing optimum recording. Since the high frequency signal L6 has a sufficient resolution, it may be asynchronous with the channel clock L3.

In the optical information recording / reproducing apparatus of this embodiment, as described above, the integral multiple N of the channel clock period T is used.
(N is an integer of 1 or more). The frequency is such that the pulse width can be corrected with sufficient resolution to obtain an optimum recording pulse, and the effect of high-frequency superimposition during reproduction described below fully appears. Any frequency is acceptable.

Next, when information is reproduced, the LD driving circuit 1 is instructed to output an LD driving current for reproduction power by the driving current control signal L5, so that the LD driving current L2 is output in a DC manner. Is controlled to be However, during reproduction, the switch 15 is turned on, and the high-frequency superimposed signal L7 is superimposed on the LD drive current L2, resulting in an LD drive current having a high-frequency component.

The high frequency superimposed signal L7 is obtained by converting the high frequency signal L6 output from the high frequency signal
The superimposed amplitude is adjusted by 3 and AC-coupled by an AC coupling circuit 14 (specifically, a capacitor). For example, the relationship between the LD drive current L2 on which a high-frequency signal is superimposed at the time of reproduction and the emission waveform is as shown in the diagram in FIG.

In FIG. 5, the driving current-emission power characteristic is shown at the center. The LD driving current L2 is switched at a high speed so that the lowest peak current value becomes equal to or less than the threshold current around the DC current value at which the light emission power becomes Po. The light emission power reaches the peak value Po at the maximum peak current value, but the light emission power can be regarded as substantially zero below the threshold current, so that the light emission waveform has a pulse waveform of 0 to Po. By emitting light with a high-frequency pulse as described above,
Noise due to return light at the time of reproduction can be reduced (see the reproduction period in FIGS. 2 and 3).

As described above, the high frequency signal generator 12 can be shared by turning on / off the switch 15 at the time of reproduction / recording, and simplification of a circuit related to reduction of return light from the optical disk 6 can be achieved. Can be planned.

This optical information recording / reproducing apparatus has a high-frequency signal generating apparatus 12 for generating a signal having a frequency higher than the channel clock. When reproducing information recorded on the optical disk 6, the high-frequency signal generating apparatus 12 is used. The generated high-frequency signal is superimposed on the DC current for driving the LD so that the reproducing LD driving current has a high-frequency component. When information is recorded on the optical disk 6, the channel clock and the high-frequency signal generation are performed. Since a pulse according to a predetermined light emission rule is formed using the high-frequency signal generated by the device 12, the circuit scale can be simplified by sharing the high-frequency generation circuit for high-frequency superimposition and recording pulse width correction. Can be.

The predetermined light emission rule for recording information on the optical disc 6 is N ×
Since the multi-pulse train emits a plurality of pulses with respect to the T-length pulse, distortion of the recording mark due to heat generation can be prevented.

Further, a multi-pulse train for recording on the optical disk 6 is composed of a head heating pulse and a plurality of succeeding rear heating pulse trains.
Alternatively, since the rear heating pulse train forms a basic pulse using the channel clock as a basic clock and corrects the basic pulse with a high frequency signal to form a pulse according to a predetermined light emission rule, the recording pulse width can be corrected with high precision. Can do it.

Further, a multi-pulse train for recording on the optical disk 6 is composed of a head heating pulse and a head cooling pulse, and a plurality of subsequent rear heating pulses and a rear cooling pulse. The pulse train and / or the last rear cooling pulse (final cooling pulse) constitutes a basic pulse using the channel clock as a basic clock, and a pulse according to a predetermined light emission rule is formed by correcting the basic pulse with a high-frequency signal. The recording pulse width can be corrected with high accuracy.

Next, another process of the optical information recording / reproducing apparatus will be described. In this process, when a recording pulse is generated by the recording pulse generation device 11 during recording, the controller 10
6 without using the channel clock L3 output from the
(E), the high-frequency signal L6 is frequency-divided to generate a recording pulse. Therefore, the optical waveform becomes a waveform synchronized with the high-frequency signal L6, and becomes asynchronous with the channel clock. This eliminates the need to output the channel clock L3 to the recording pulse generation device 11.

As described above, when information is recorded on the optical disk 6, the high-frequency signal generated by the high-frequency signal generator 12 is appropriately divided to form a pulse according to a predetermined light emission rule. Thus, the circuit scale can be simplified by sharing the high-frequency generation circuit for the high-frequency superimposition and for the recording pulse generation, and the recording pulse width can be corrected with high accuracy.

Next, an optical information recording / reproducing apparatus according to another embodiment of the present invention will be described. FIG. 7 is a diagram showing a configuration of an optical information recording / reproducing apparatus according to another embodiment of the present invention. The configuration is basically the same as that of the optical information recording / reproducing apparatus shown in FIG. The difference is that the channel clock L3 is supplied to the signal generator 12. Also, since the module and the signal name are common to FIG. 1, the same numbers are used.

That is, the controller 10, the recording pulse generator 11, the high frequency signal generator 12, etc., multiply the channel clock cycle to generate a signal having a frequency higher than the channel clock cycle,
When reproducing information recorded on a recording medium, a high-frequency signal generated by high-frequency signal generating means is superimposed on a driving DC current of the semiconductor laser light source to generate a reproducing driving current to which a high-frequency component is added, and When information is recorded thereon, it functions as a means for forming a light emission pulse according to a predetermined light emission rule using the channel clock cycle and the high frequency signal generated by the high frequency generation means.

This optical information recording / reproducing apparatus generates a high-frequency signal L6 by multiplying the channel clock L3 by the high-frequency signal generator 12. If the multiplication number is, for example, 10 times, about 260 MH as in the above-described embodiment.
z, which is 高周波 of the channel clock cycle
The recording pulse width can be corrected with a resolution of 0.

Generally, when multiplying a clock, a PLL
Since a (Phase Locked Loop) circuit is used, the phase is aligned with the original clock. Therefore, in this optical information recording / reproducing apparatus, FIG.
In the case of performing the recording pulse width correction as shown by the broken line in the recording period (b), the correction can be performed in the same phase as the channel clock as the basic clock, so that the correction can be performed with higher accuracy than in the above-described processing. Can be corrected.

In the optical information recording / reproducing apparatus of this embodiment, the processing in the case where the multiplication factor is set to 10 has been described.
This number does not limit the scope of the present invention.

As described above, by multiplying the channel clock to generate a signal having a frequency higher than that of the channel clock, the high frequency generating circuit is shared by the high frequency superimposing circuit and the recording pulse width correcting circuit. The circuit scale can be simplified, and the recording pulse width can be corrected with high accuracy.

Next, another process of the optical information recording / reproducing apparatus will be described. In this process, the method of correcting the pulse width of each recording pulse is switched according to the type of the optical disk 6. The type of the optical disc 6 is, for example, a phase change type medium and a dye-based medium (see FIG. 2B and FIG. 3B).

Further, even for the same phase-change type medium or dye-based medium, the pulse width correction method may be switched according to the media manufacturer or brand. For example,
As shown in FIG. 8, the correction of the leading pulse width and the heating pulse width of the dye-based medium is corrected so as to be optimal for each medium type.

As described above, the method of correcting the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse by the high-frequency signal is switched according to the type of the optical disk 6. Accordingly, an optimum recording pulse width can be generated.

Next, still another process of the optical information recording / reproducing apparatus will be described. In this process, the method of correcting the pulse width of each recording pulse is switched according to the recording linear velocity.

For example, CAV (Constant An)
In the case of a configuration in which the recording linear velocity changes, such as in the case of a recording method using a GVU (gual velocity) recording method, the recording power per unit density decreases as the recording linear velocity increases.

Therefore, as shown in FIG. 9, when the linear velocity increases, the recording power per unit density can be reduced by increasing the pulse width of the head heating pulse or the pulse width of the subsequent multi-pulse. Can be prevented.

As described above, the method of correcting the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse by the high-frequency signal is switched according to the recording linear velocity. It is possible to generate an appropriate recording pulse width.

Next, another process of the optical information recording / reproducing apparatus will be described. In this process, the method of correcting the pulse width of each recording pulse is switched according to the length of the space immediately before the current recording mark.

For example, when recording on a dye-based medium, if the immediately preceding space is as short as 3T or 4T, the leading end of the recording mark is distorted like tears due to the effect of the recording power on the mark immediately before the current mark. I will.

Therefore, as shown in FIG. 10B, when the immediately preceding space length is short (in this embodiment, when ≦ 4T), the pulse width of the first heating pulse is shortened (the distance from the immediately preceding mark is reduced). By increasing the length, it is possible to avoid the influence of heat due to recording of the immediately preceding mark.

As described above, the method of correcting the head heating pulse by the high-frequency signal is switched according to the length of the space immediately before the current recording mark. The distortion of the recording mark due to the influence can be prevented.

Next, still another process of the optical information recording / reproducing apparatus will be described. In this process, as shown in FIG. 11C, when a recording pulse is generated by the recording pulse generation device 11 during recording, each of the recording pulses of the leading heating pulse and the subsequent multi-pulse train is composed of a pulse train by the high frequency signal L6. I do.

As described above, the pulse according to the predetermined light emission rule is constituted by the pulse train based on the high-frequency signal generated by the high-frequency signal generator 12, so that the high-frequency pulse can be emitted even at the time of recording. Noise due to returning light from the light source can be reduced.

[0086]

As described above, according to the optical information recording / reproducing apparatus of the present invention, it is possible to simplify the circuit configuration for reducing the noise due to the return light from the recording medium.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of a pulse waveform formed by the recording pulse generation device shown in FIG.

FIG. 3 is an explanatory diagram of a pulse waveform formed by the recording pulse generation device shown in FIG. 1;

FIG. 4 is a waveform chart for explaining fine adjustment of a pulse width in the recording pulse generation device shown in FIG. 1;

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 a light emission waveform.

FIG. 6 is a waveform chart for explaining recording pulse generation in the recording pulse generation device shown in FIG. 1;

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

FIG. 8 is an explanatory diagram of a switching process of a pulse width correction method in the optical information recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 9 is an explanatory diagram of another switching process of the pulse width correction method in the optical information recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 10 is an explanatory diagram of still another switching process of the pulse width correction method in the optical information recording / reproducing device according to the embodiment of the present invention.

FIG. 11 is an explanatory diagram showing a configuration of a pulse waveform generated by a recording pulse generating device of the optical information recording / reproducing device according to the embodiment of the present invention.

FIG. 12 is an explanatory diagram showing an example of a recording waveform when information is recorded on a phase change medium.

FIG. 13 is an explanatory diagram showing an example of a recording waveform when information is recorded on a dye-based medium.

FIG. 14 is an explanatory diagram showing an example of a signal waveform output from the high-frequency signal generator of the optical information recording / reproducing apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 1: LD drive circuit 2: LD light source 3: Collimating lens 4: Polarizing beam splitter 5: Objective lens 6: Optical disk 7: Objective lens 8: Light receiving element 9: Head amplifier 10: Controller 11: Recording pulse generator 12: High frequency signal Generator 13: Amplitude adjustment circuit 14: AC coupling circuit 15: Switch L1: Recording pulse control signal L2: LD drive current L3: Channel clock L4: 8-16 modulation code data L5: Drive current control signal L6: High frequency signal L7: High frequency superimposed signal

Claims (10)

[Claims] When a laser beam is emitted from a semiconductor laser light source onto a recording medium to record information comprising a pulse having a length that is a positive integer multiple of a channel clock period based on a predetermined recording modulation method, the semiconductor laser An optical information recording / reproducing apparatus for forming a mark or a space on the recording medium by causing a light source to emit a pulse according to a predetermined light emission rule; a high frequency signal generating means for generating a signal having a frequency higher than the channel clock cycle; When reproducing information recorded on a medium, a high-frequency signal generated by the high-frequency signal generating means is superimposed on a driving DC current of the semiconductor laser light source to generate a reproduction driving current to which the high-frequency component is added, When recording information on the recording medium, the channel clock cycle and the high-frequency signal generated by the high-frequency generating means are used. DOO optical information recording and reproducing apparatus characterized in that a means for forming a light-emitting pulse by said predetermined light emission rule used. 2. The method according to claim 1, wherein the semiconductor laser light source emits a laser beam from a semiconductor laser light source onto a recording medium and records information comprising a pulse having a length that is a positive integer multiple of a channel clock cycle based on a predetermined recording modulation method. An optical information recording / reproducing apparatus for forming a mark or a space on the recording medium by causing a light source to emit a pulse according to a predetermined light emission rule; a high frequency signal generating means for generating a signal having a frequency higher than the channel clock cycle; When reproducing information recorded on a medium, a high-frequency signal generated by the high-frequency signal generating means is superimposed on a driving DC current of the semiconductor laser light source to generate a reproduction driving current to which the high-frequency component is added, When information is recorded on the recording medium, the frequency of the high-frequency signal generated by the high-frequency signal generating means is appropriately divided. Providing the means to form a light emitting pulse by said predetermined light emission rule What optical information recording reproducing apparatus according to claim. 3. A method according to claim 1, wherein a laser beam is emitted from a semiconductor laser light source onto a recording medium to record information comprising a pulse having a length that is a positive integer multiple of a channel clock period based on a predetermined recording modulation method. In an optical information recording / reproducing apparatus for forming a mark or space on the recording medium by causing a light source to emit pulse light according to a predetermined light emission rule, a signal having a frequency higher than the channel clock cycle is generated by multiplying the channel clock cycle. High-frequency signal generation means, and when reproducing information recorded on the recording medium, the high-frequency signal generated by the high-frequency signal generation means is superimposed on a driving DC current of the semiconductor laser light source, and the high-frequency component is added. When a drive current for reproduction is generated and information is recorded on the recording medium, the channel clock cycle and the high frequency The optical information recording and reproducing apparatus characterized in that a means for forming a light-emitting pulse by said predetermined light emission rule by using the high-frequency signal generated by the means. 4. The optical information recording / reproducing apparatus according to claim 1, wherein the light emission pulse according to the predetermined light emission rule is constituted by a pulse train based on a high-frequency signal generated by the high-frequency signal generation means. Optical information recording / reproducing device. 5. The optical information recording / reproducing apparatus according to claim 1, wherein the predetermined light emission rule when recording information on the recording medium is set to the channel according to the recording modulation method. An optical information recording / reproducing apparatus, wherein a pulse having a length of a positive integer multiple of a clock cycle is formed into a multi-pulse train for emitting a plurality of pulses. 6. The optical information recording / reproducing apparatus according to claim 5, wherein the multi-pulse train is composed of a head heating pulse and a plurality of subsequent rear heating pulse trains, and the head heating is performed using the channel clock cycle as a basic clock. Optical information recording / reproducing, wherein a basic pulse of a pulse and / or a rear heating pulse train is formed, and the basic pulse is corrected based on the high frequency signal to form a light emission pulse according to the predetermined light emission rule. apparatus. 7. The optical information recording / reproducing apparatus according to claim 5, wherein the multi-pulse train includes a head heating pulse, a head cooling pulse, and a plurality of subsequent rear heating pulses and a rear cooling pulse. Using a cycle as a basic clock, a basic pulse of the first heating pulse and / or the rear heating pulse train and / or a final cooling pulse is formed, and the basic pulse is corrected based on the high-frequency signal to generate an emission pulse according to the predetermined emission rule. An optical information recording / reproducing apparatus characterized by being formed. 8. The optical information recording / reproducing apparatus according to claim 6, wherein the type of the correction processing based on the high frequency signal of the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse is changed to the type of the recording medium. An optical information recording / reproducing apparatus characterized in that the switching is performed according to the following. 9. The optical information recording / reproducing apparatus according to claim 6, wherein the type of correction processing based on a high-frequency signal of the first heating pulse and / or the rear heating pulse train and / or the last cooling pulse is determined according to a recording linear velocity. An optical information recording / reproducing apparatus characterized in that it is switched by switching. 10. The optical information recording / reproducing apparatus according to claim 5, wherein a type of correction processing based on a high-frequency signal of the first heating pulse is switched according to a length of a space immediately before a current recording mark. An optical information recording / reproducing apparatus characterized by the above-mentioned.