JP2001155359A - Optical disk recording device and optical disk recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk recording device capable of always recording information in a state in which a tilt is the best by performing tilt control during recording the information on a recordable optical disk. SOLUTION: This device is provided with an optical pickup 10 which converges a recording laser beam which is obtained by light modulating a laser beam by using a multipath signal having ternary levels (11>12>13) formed based on an input recording signal and projects the converged laser beam on the recording surface of an optical disk 1 and sample-hold circuits 31, 32 which sample and hold an RF signal corresponding to a returned light beam which is reflected from the disk 1 by projecting the recording laser beam to the disk 1 with the pickup 10 at timings ta, tb when the maximum value and the minimum value 11, 13 among the ternary levels are to be detected and the device controls the tilt of the pickup 10 so that the RF signal corresponding to the timing of the maximum value of the multipath signal sampled and held in the circuits 31, 32 always has lower values.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording apparatus capable of performing good tilt control of a tilt in a radial direction and / or a tangential direction even while recording information on an optical disk capable of optical recording and reproduction. The present invention relates to an apparatus and an optical disk recording method.

[0002]

2. Description of the Related Art Conventionally, tilt control at the time of recording / reproduction on an optically recordable / reproducible optical disk is performed by extracting a sub-beam from a laser beam emitted from a tilt sensor or a light source of an optical pickup and receiving these return lights. Tilt control is performed by determining the inclination by using a detection optical sensor, or by detecting a reproduction signal of information recorded on the optical disc and determining the inclination.

[0003]

In the tilt determination method using the tilt sensor or the sub-beam, correct tilt determination cannot be performed due to a displacement of the position of the sensor or the sub-beam, and the mechanism becomes complicated. There is a problem that it is disadvantageous in miniaturization, weight reduction, and cost reduction. Further, the tilt determination method using a reproduced signal of recorded information has a problem that tilt control during recording cannot be performed.

Accordingly, the present invention is to perform tilt control when a tilt occurs, without performing tilt determination using a tilt sensor or a sub-beam, during recording on a phase-change type optical disk that is mainly capable of recording and reproduction. It is an object of the present invention to provide an optical disk recording device and an optical disk recording method that enable optimum information recording and that can form marks or spaces of appropriate dimensions and shapes on tracks on an optical disk.

[0005]

In order to achieve the above object, the present invention provides an optical disk recording apparatus and an optical disk recording method having the following constitutions (1) to (4). (1) As shown in FIG. 1, an optical disc recording apparatus for recording information on a recordable / reproducible optical disc 1, comprising a plurality of levels (ternary values) formed based on an input recording signal (FIG. 2A). Level (maximum level (Peak level) l1,
Intermediate level (Erase level) l2, minimum level (Bot)
tom level) l3. l1>l2> l3)) (the recording strategy shown in FIG. 2B),
An irradiating means (optical pickup 10) for condensing a recording laser light obtained by optically modulating a laser light (emitted from a laser light source) and irradiating the recording laser light onto the recording surface of the optical disc 1; The output (RF signal) corresponding to the return laser light (FIG. 2C) reflected from the recording surface of the optical disk 1 by the irradiation of the recording laser light is output to a plurality of levels (ternary levels) 11 of the multipath signal. , L2, l3
At which the maximum and minimum values l1 and l3 are detected, respectively (ta and tb in FIGS. 2D and 2E)
And the output value corresponding to the timing of the maximum value of the multipath signal sampled and held by the sample and hold means 31 and 32 is always lower. The tilt of the irradiation unit 10 in the radial direction and / or the tangential direction is tilt-controlled so that
5, memory 36, D / A conversion circuit 37, tilt motor 3
8. An optical disc recording apparatus, comprising: a control unit (provided with a tilt mechanism 39). (2) The timing at which the maximum value and the minimum value among a plurality of levels (ternary levels) of the multipath signal are respectively detected is within a period in which a mark or space is formed on the recording surface of the optical disc. 2. The optical disk recording apparatus according to claim 1, wherein: (3) An optical disc recording method for recording information on a recordable / reproducible optical disc, wherein recording is performed by optically modulating a laser beam using a multi-pass signal of a plurality of levels formed based on an input recording signal. Condensing the laser light and irradiating it on the recording surface of the optical disc, and outputting an output corresponding to the return laser light reflected from the recording surface of the optical disc by the irradiation of the recording laser light, At the timing when the maximum value and the minimum value among the plurality of levels are respectively detected, the step of sampling and holding, and the output value according to the timing of the maximum value of the sampled and held multipath signal is always a lower value. Controlling the tilt of the irradiating means in a radial direction and / or a tangential direction such that . (4) The timing at which the maximum value and the minimum value among the plurality of levels of the multipath signal are respectively detected is within a period in which a mark or a space is formed on the recording surface of the optical disc. 4. The optical disk recording method according to claim 3, wherein:

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an optical disk recording apparatus and an optical disk recording method according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a main block diagram of an optical disk recording apparatus of the present invention, and FIG. 2 is a view for explaining a recording operation when a mark and a space are formed on a phase-change type optical disk by a recording laser beam using the apparatus of the present invention. FIG. 3 is a timing chart showing the reflectivity with respect to the surface laser power during recording on a phase change optical disk.

FIG. 1 is a block diagram of an optical disk 1 formed of a phase-change type optical recording medium and capable of repeatedly recording and reproducing information. The optical disk 1 is rotated by a spindle motor (not shown). The configuration of a recording / reproducing system when the present invention is applied to an optical disk recording / reproducing apparatus for optically recording / reproducing digital data of a predetermined data format by scanning a signal track with a laser beam emitted from the optical pickup 10 is described. Is shown.

In the optical pickup 10 of this optical disk recording / reproducing apparatus, a laser beam emitted from a semiconductor laser 11 as a laser light source and a laser beam optically modulated by a multipath signal described later are converted into parallel light by a collimating lens 12. The optical disk 1 is turned into a beam, and is passed through a beam splitter 13 and an objective lens 14.
Irradiation is performed so as to be focused on the track on the upper signal recording surface. A reflected light beam (return laser light) of the laser beam irradiated on the signal recording surface of the optical disk 1 and reflected from the signal recording surface is reflected by a beam splitter 13 and transmitted to a photodetector 16 as a light receiving element via a cylindrical lens 15. Be guided. Here, the objective lens 14
The so-called two-axis driving device having the driving coils 25 and 26 controls the movement in the optical axis direction and the direction orthogonal to the optical axis.

The photodetector 16 has, for example, a structure in which a light receiving portion is divided into four, and a light detection signal from each light receiving portion is supplied to a matrix circuit 22 via an amplifier 21. As a result, the sum or difference of these photodetection signals is obtained and extracted as a so-called RF signal, a focus error signal, a tracking error signal, or the like. The focus error signal and the tracking error signal are sent to the respective drive coils 18 and 19 of the two-axis drive device via the phase compensation circuit 23 and the servo drive circuit 24, so that focus servo and tracking servo are performed. . The RF signal is a sum signal of output signals from the respective light receiving units, and the RF signal is sent to two sample and hold circuits 31 and 32 that sample at two different timings as described later.

The recording signal input terminal 41 is supplied with a recording signal obtained by modulating information to be recorded, for example, by 8-16. This recording signal is a binary data pulse signal (FIG. 2).
(Shown in (A)), which is supplied to the multi-pulse generation circuit 42, where it is sent to the laser drive circuit 45 as a multi-pass signal that generates a plurality of pulse trains. Also, CP
A laser power control signal is sent from U35 via the D / A conversion circuit 44. Thereby, for example, as shown in FIG. 2B, the laser diode 11 is pulse-driven by ternary laser power, and the recording laser beam is irradiated toward the recording surface of the optical disc 1.

FIG. 3 shows a change in reflectance with respect to a recording laser beam (table surface laser power) irradiated from the laser diode 11 to the recording surface of the optical disc 1 during recording. The optical disc 1 irradiates a laser beam of a combination of a plurality of levels of pulse-modulated laser power, and changes the state of the optical disc 1 irradiated with the laser beam to crystal or amorphous.
It is common to change the state to form a mark or space. At this time, if a recording laser power sufficient to form a mark is applied, the optical disk 1 reacts due to the heat, and immediately becomes an amorphous state, so that the reflectivity decreases.

Here, as shown in FIG. 2B, a ternary recording laser power (Peak (11 level),
Regarding the reflectivity when irradiating Erase (l2 level) and Bottom (l3 level), the surface laser power of the recording surface of the optical disk 1 at the best point of tilt and focus is optimal for recording as shown in FIG. Since the peak power Pa is sufficient (sufficient), the reflected light amount Ra is stable. Here, the recording laser power in the case of the Peak level (maximum value level) l1, that is, the peak power Pa) is as follows.
It has sufficient power to form a mark. The recording laser power at the Bottom level (minimum value level) 13, that is, the bottom power Pb, is a power that cannot form or erase a mark or a space.
Further, the recording laser power at the Erase level (intermediate value level) l2 is an intermediate value between the aforementioned l1 level and l3 level, and is not sufficient power to form the mark. Or, it has sufficient power to erase the space. However, when the objective lens 14 is tilted (that is, tilted in the radial direction and / or tangential direction), the beam profile applied to the board is distorted and spread, and the laser power of the board is reduced to Px, and accordingly, the reflectance is increased. Rx and increases.

Since the change in the intensity of the return laser beam during recording is strongly affected by the light modulation waveform (recording strategy, FIG. 2B), the change in the amount of reflected light (reflectance) is mixed with the recording strategy. Detected in shape. Therefore, FIG.
Return laser light as shown in FIG. 3C is detected, and the peak return light intensity Va at the best tilt point and the tilt (tilt)
A difference occurs in the peak return light intensity Vx at the time of occurrence of. The present invention focuses on this point, and always lowers the peak return light intensity (maximum level 11) during recording (ie, always obtains the peak return light intensity Va at the best tilt point). Tilt control can be performed.

Returning to FIG. 1, in each of the sample and hold circuits 31 and 32, in response to each sampling pulse from the timing generation circuit 43, the recording signal shown in FIG. The intensity of the return laser beam (FIG. 2C) is detected during the period from to t2, that is, the period during which the mark is recorded. For this reason, the time t1 to mark formation
Sampling is performed at a predetermined time ta and a predetermined time tb during t2. The timing generation circuit 43 receives the input signal shown in FIG.
In response to the recording signal shown in FIG. 2A, pulses A and B having timings shown in FIGS. 2D and 2E are respectively output.

FIG. 2D shows a sampling pulse A which is sent to the sample and hold circuit 31 and is sampled at the timing of the time ta. The RF at the time when the intensity of the returning laser beam at the time of the mark formation becomes maximum is shown in FIG. The signal output Va is sampled. FIG. 2E shows a sampling pulse B which is sent to the sample and hold circuit 32 and is sampled at the timing of the time tb. The RF signal output Vb at the time when the intensity of the returning laser beam at the time of mark formation becomes minimum is shown. Has been sampled.

The sample output Va from the sample hold circuit 31 is sent to an A / D conversion circuit 33, where the A / D
After being D-converted, it is output to the CPU 35 as a signal Va '. The sample output Vb from the sample hold circuit 32 is sent to an A / D conversion circuit 34, where the A / D
After the conversion, it is output to the CPU 35 as a signal Vb '. The CPU 35 calculates the value of | Va′−Vb ′ | and temporarily stores the calculation result in the memory 36. CPU
Reference numeral 35 sequentially compares the calculated value of the returning laser beam coming from the optical disc 1 with the above-mentioned value stored in the memory 36, and determines the minimum value among the sequentially compared comparison values in the memory 36.
To remember again. In this way, the amount of tilt correction is digitally processed so that the calculated value is always minimized, and the obtained tilt control signal is converted to an analog signal via the D / A conversion circuit 37. And tilt motor 3
8 and the optical pickup 10 by the tilt mechanism 39.
The tilt control during recording is performed so that the tilt of.

According to the embodiment of the present invention, during recording of information on a phase change optical disk, a recording laser beam is formed by a combination of a plurality of levels of recording laser power and a pulse signal corresponding to a recording signal. Irradiating, at a timing according to the pulse train, within a predetermined time range required until a mark is formed on the optical disc by the recording laser beam, and at a time point when the intensity of the laser beam returned from the optical disc becomes maximum. One detection signal output is sampled, and at a timing according to the pulse train, the intensity of the return laser beam from the optical disc is within a predetermined time range required for a mark to be formed on the optical disc by the recording laser beam. Sampling the second detection signal output at the time when the By absolute value of the difference between the sampled value of the second detection signal output (amplitude) controls the tilt so as to minimize, always to allow recording of information in the tilt best state.

[0018]

According to the present invention having the above-described structure, tilt control can be performed during information recording without using, for example, a tilt sensor or a sub-beam for tilt detection, and information recording can always be performed in the best tilt state. I can do it. Further, since a tilt sensor or a sub-beam is not required, the size and weight can be reduced mechanically, which is advantageous in cost reduction.

[Brief description of the drawings]

FIG. 1 is a main block configuration diagram of an optical disk recording device of the present invention.

FIG. 2 is a time chart for explaining a recording operation when a mark and a space are formed by a recording laser beam on a phase-change optical disk using the apparatus of the present invention.

FIG. 3 is a diagram showing a reflectance with respect to a surface laser power during recording on a phase change optical disk.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical disk 10 Optical pickup (irradiation means) 31, 32 Sample hold circuit (sample hold means) 35 CPU 36 Memory 37, 44 D / A conversion circuit 38 Tilt motor 39 Tilt mechanism l1 Maximum value level, Peak level l2 Intermediate value level, Erase Level 13 Minimum level, Bottom level

Claims (4)

[Claims] 1. An optical disc recording apparatus for recording information on a recordable / reproducible optical disc, comprising: a plurality of levels of a multipath signal formed based on an input recording signal; Irradiating means for condensing a recording laser beam obtained by optically modulating the light, and irradiating the recording laser light onto the recording surface of the optical disc; Sample-and-hold means for sampling and holding an output corresponding to the laser light at timings when a maximum value and a minimum value among a plurality of levels of the multipath signal are respectively detected; and The output value according to the timing of the maximum value of the path signal, so that always lower value, in the radial direction and or An optical disc recording apparatus, comprising: a control unit for tilt-controlling a tilt of the irradiation unit in a tangential direction. 2. A timing at which a maximum value and a minimum value among a plurality of levels of the multipath signal are detected within a period in which a mark or a space is formed on a recording surface of the optical disk. The optical disk recording device according to claim 1, wherein: 3. An optical disc recording method for recording information on a recordable / reproducible optical disc, wherein the optical disc is obtained by optically modulating a laser beam using a multi-pass signal of a plurality of levels formed based on an input recording signal. Condensing the recording laser light, and irradiating the recording laser light on the recording surface of the optical disk; and outputting the output corresponding to the return laser light reflected from the recording surface of the optical disk by the irradiation of the recording laser light to the multi-pass. A step of sampling and holding at a timing at which a maximum value and a minimum value among a plurality of levels of the signal are respectively detected; and the output value according to the timing of the maximum value of the sampled and held multipath signal is always higher. Controlling the tilt of the irradiating means in a radial direction and / or a tangential direction so as to have a low value. Recording method. 4. A timing at which a maximum value and a minimum value among a plurality of levels of the multipath signal are respectively detected within a period in which a mark or a space is formed on a recording surface of the optical disc. 4. The optical disk recording method according to claim 3, wherein: