JP2001184689A - Optical disk recorder and optical disk recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk recorder recording information always in a tilt best state by performing tilt control while recording the information for a recordable optical disk. SOLUTION: This recorder is provided with an optical pickup 10 using a multi-pulse signal formed based on an input recording signal, converging a recording laser beam obtained light modulating a laser beam with ternary level 11>12>13 and irradiating it onto the recording surface of the optical disk 1, a sample-hold circuit 31 sample-holding an RF signal according to a return laser beam reflected from the optical disk 1 by the irradiation of the recording laser beam of the optical pickup 10 at the timing ta or tb that a recordable laser level 11 or an erasable laser level 12 among the ternary level are detected and a CPU 44 tilt controlling the optical pickup 10 so that the RF signal corresponding to the erasable laser level of the return laser beam output sample-held by the sample-hold circuit 31 becomes always a lower value.

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 an optical disc 1 (recordable and reproducible),
A multi-pulse signal (the recording strategy shown in FIG. 2B) formed based on the input recording signal (FIG. 2A)
A plurality of levels including erasing levels (intermediate level (Erase level) 12) (ternary level (maximum level (Peak level) 11), intermediate level (Erase level) 12 and minimum level (Bottom level) 13.11 >L2> l3)) the recording laser light pulse-modulated in
Irradiation means for irradiating the recording surface of the optical disc (optical pickup 10)
The return laser light output (the RF signal shown in FIG. 2C) reflected from the recording surface of the optical disc 1 by the irradiation of the recording laser light is used to detect the output value corresponding to the erasing level l2 ( A sample and hold means (sample and hold circuit 3) for performing sample and hold at the timing ta of the sampling pulse A shown in FIG. 2D and the timing tb of the sampling pulse B shown in FIG.
1) and a radial and / or tangential direction (only in the radial direction, only in the tangential direction, so that the output value corresponding to the erase level obtained by sample-holding is always lower).
Control means for controlling the tilt of the irradiating means 10 in the radial direction and the tangential direction (including a CPU 33, a memory 34, a D / A conversion circuit 35, a tilt motor 36, and a tilt mechanism 37). Optical disk recording device. (2) The optical disc recording apparatus according to claim 1, wherein the specific timing is within a period in which a mark or a space is formed on a recording surface of the optical disc 1. (3) An optical disk recording method for recording information on an optical disk, wherein a recording laser beam obtained by pulse-modulating a multi-pulse signal formed based on an input recording signal at a plurality of levels including an erasing level is collected. Irradiating the recording surface of the optical disk with the laser beam, and sampling and holding the return laser light output reflected from the recording surface of the optical disk by the irradiation of the recording laser beam at a timing when an output value corresponding to the erasing level is detected. And tilt-controlling the tilt of the irradiating means in a radial direction and / or a tangential direction so that an output value corresponding to the erasure level obtained by sample holding is always a lower value. An optical disk recording device characterized by the following. (4) The optical disc recording method according to claim 3, wherein the timing at which the output value corresponding to the erasing level is detected is within a period in which a mark or a space is formed on the recording surface of the optical disc.

[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 multi-pulse signal described later are converted into parallel light by a collimating lens 12. The beam is emitted through a beam splitter 13 and an objective lens 14 so as to be focused on a track on a signal recording surface of the optical disc 1. 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
Is controlled to move in the optical axis direction and in a direction perpendicular to the optical axis by a so-called two-axis driving device having driving coils 25 and 26.

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 sections. The RF signal is a sample-and-hold circuit 31 for sampling at any one timing corresponding to a recordable or erasable laser level as described later.
Has been sent to

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)), and is supplied to the multi-pulse generation circuit 42, where it is sent to the laser drive circuit 45 as a multi-pulse signal generated by generating a plurality of pulse trains. Also, C
A laser power control signal is sent from the PU 33 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) 11, ie, the peak power Pa, has a power sufficient to form a mark.
The recording laser power in the case of the Bottom level (minimum value level) 13, that is, the bottom power Pc, is a power that cannot form or erase a mark or a space. Further, the Erase level (intermediate value level Pb) l
The recording laser power in the case of 2, ie, the erasing power Pb, is an intermediate value between the above-mentioned l1 level and l3 level, which is not enough power to form the mark, but erases the mark or space. Have enough power to

However, when the objective lens 14 is tilted (that is, tilted in the radial direction and / or tangential direction), the beam profile irradiated on the board is distorted and spread,
The surface laser power decreases and the peak power Pa becomes Px, and accordingly, the reflectance increases from Ra to Rx and increases.
Further, the erasing power Pb is reduced to Py, and accordingly, the reflectance increases from Rb to Ry and increases.

Since the change in the intensity of the returning laser beam during recording is strongly influenced 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.
A return laser beam as shown in (C) is detected, and a recordable laser level Va corresponding to a value at the time of irradiation with a recordable laser level at the best tilt point, and a recordable laser when a tilt (tilt) occurs. A difference occurs in the return light intensity Vx corresponding to the level at the time of irradiation. Also, the return light intensity Vb corresponding to the value at the time of irradiation with the erasable laser level at the best tilt point, and the return light intensity corresponding to the value at the time of irradiation with the erasable laser level at the time of tilt (tilt). A difference occurs in Vy. The present invention focuses on this point, and always sets the recordable laser level during recording so that the return light intensity (maximum value level 11) corresponding to the value at the time of irradiation is always lower (that is, the recordable laser level is always at the best tilt point). To obtain a return light intensity Va corresponding to an appropriate laser level at the time of irradiation), or a return light intensity corresponding to the value at the time of irradiation (intermediate value level l2). )
(I.e., by making the erasable laser level at the best tilt point always obtain the return light intensity Vb corresponding to the value at the time of irradiation), the tilt control can be performed.

Returning to FIG. 1, in each sample-and-hold circuit 31, 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) during the period, that is, the period during which the mark is recorded, is detected. For this reason, time t1 to mark formation time t1
Sampling is performed at a predetermined time ta during t2, or at a predetermined time tb between t2 and t3. The timing generation circuit 43 outputs a pulse A or B having a timing as shown in FIG. 2D or FIG. 2E in accordance with the input recording signal shown in FIG.

That is, FIG. 2 (D) or FIG. 2 (E)
A sampling pulse A or B sent to the sample and hold circuit 31 for sampling at the timing of the time ta or tb, and samples the RF signal output Va at the time when the intensity of the returning laser beam at the time of forming the mark becomes maximum.

The sample output Va or Vb from the sample and hold circuit 31 is sent to an A / D conversion circuit 32, where it is A / D converted, and then the signal Va 'or
It is output to the CPU 33 as Vb '. The CPU 33 temporarily stores Va ′ or Vb ′ in the memory 34. The CPU 33 sequentially compares the calculated value of the return laser light coming from the optical disc 1 one after another with the above-mentioned value stored in the memory 34, and stores the minimum value of the sequentially compared comparison values in the memory 34 again. . In this way, the amount of tilt correction is digitally processed so that the calculated value is always minimized, and the tilt control signal obtained here is converted to D.
The signal is converted into an analog signal via the / A conversion circuit 35 and sent to the tilt motor 36, and the tilt mechanism 37 controls the tilt during recording so that the tilt of the optical pickup 10 is optimized.

According to the embodiment of the present invention, during recording of information on a phase-change type optical disk, a recording laser beam is controlled by a combination of a plurality of levels of recording laser power and a multi-pulse signal corresponding to a recording signal. And within a predetermined time required for the recording laser beam to form a mark or space on the optical disc at a timing according to the pulse train, and record or erase the intensity of the returning laser light from the optical disc. By sampling the first detection signal output at any one timing corresponding to a possible laser level and controlling the tilt so that this value is minimized, information can always be recorded in the best tilt state. ing.

[0019]

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 pick-up (irradiation means) 31 Sample hold circuit (sample hold means) 33 CPU 34 Memory 35,44 D / A conversion circuit 36 Tilt motor 37 Tilt mechanism 11 Maximum value level, Peak level 12 Intermediate value level, Erase level ( (Erase level) l3 Minimum level, Bottom level

Claims (4)

[Claims] 1. An optical disk recording apparatus for recording information on an optical disk, comprising: condensing a recording laser beam obtained by pulse-modulating a multi-pulse signal formed based on an input recording signal at a plurality of levels including an erasing level. Irradiating means for irradiating the recording surface of the optical disc, and irradiating the recording laser light with the return laser light output reflected from the recording surface of the optical disc at a timing at which an output value corresponding to the erase level is detected. A sample-and-hold means for holding, and an output value corresponding to the erase level obtained by sample-and-hold so that the output value is always lower than that in the radial direction.
An optical disc recording apparatus, comprising: a control unit for performing tilt control on a tilt of the irradiation unit in a tangential direction. 2. The optical disk recording apparatus according to claim 1, wherein a timing at which the output value corresponding to the erasing level is detected is within a period in which a mark or a space is formed on a recording surface of the optical disk. apparatus. 3. An optical disk recording method for recording information on an optical disk, comprising: condensing a recording laser beam obtained by pulse-modulating a multi-pulse signal formed based on an input recording signal at a plurality of levels including an erasing level. Irradiating the recording laser beam onto the recording surface of the optical disc, and sampling the return laser beam output reflected from the recording surface of the optical disc by the irradiation of the recording laser beam at a timing when an output value corresponding to the erasing level is detected. And the output value corresponding to the erase level obtained by sample-and-hold is always lower than that in the radial direction.
Or tilt control of the inclination of the irradiation means in the tangential direction. 4. The optical disk recording apparatus according to claim 3, wherein the timing at which the output value corresponding to the erase level is detected is within a period in which a mark or a space is formed on the recording surface of the optical disk. Method.