JP2002150560A - Optical disk recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a precise and high-density recording to a phase change recording medium the recording condition of which depends on linear velocity under the control of zone CAV where a recording frequency is fixed for every zone and the shortest recording wavelength is nearly fixed between the zones. SOLUTION: Trial writing is performed under a recording condition previously given to the respective zones divided in a radial direction. The deviation of a waveform such as the asymmetry of the reproduced signal is detected. After correcting the recording condition so as to correct the deviation, data is recorded. Thus, ZCAV recording of a phase change type which is largely dependent on the linear velocity is satisfactorily carried out.

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 for storing digital information signals on a phase change medium (optical disk) at a high density.

[0002]

2. Description of the Related Art Recording and reproduction can be performed on a groove having a meandering (hereinafter referred to as wobble) formed on an optical disk.
DVD-RW has been conventionally proposed for an optical disc in which auxiliary information (hereinafter, referred to as land prepits) is recorded in advance on a land portion existing between grooves.

[0003]

SUMMARY OF THE INVENTION However, DVD-R
Since W performs recording and reproduction at a constant linear velocity, there is a portion where adjacent wobbles have an opposite phase, crosstalk from an adjacent track increases, and an area that cannot be used for recording due to deterioration of signal quality is obtained. There are multiple on the disk surface. In addition, since the phase is reversed, the land pre-pit signal may be deteriorated. Further, when performing a data seek for a large distance in the radial direction, it takes a long time until the rotation speed of the spindle motor falls within a range in which data can be reproduced. Therefore, as a solution to these problems, the present applicant has performed recording and reproduction on a disk having a wobble of a single frequency over the entire circumference of the disk by a zone CAV method in which the disk rotation speed is kept constant and the recording frequency is changed for each zone. (Japanese Patent Application No. 11-2).
No. 74068). According to this proposal, the phases of adjacent wobbles are always the same, and the seek time can be reduced by keeping the disk rotation speed constant. However, DVD-R
In a phase change medium often used for high-density optical discs such as W, the recording condition (laser irradiation condition) changes according to the linear velocity. Therefore, a proper recording cannot be performed by a recording control method having no difference. To address this, a method has been proposed in which recording conditions corresponding to the recording frequency are obtained for each zone by reproducing the auxiliary information of the land portion, and the recording laser irradiation conditions are set according to the information to perform recording. (Japanese Patent Application No. 2000-53291). However, in order to perform high-precision recording on an even higher-density optical disk medium, it is necessary to avoid a deterioration in reproduction quality due to deviation from an optimum recording condition due to environmental conditions such as variations in individual disks and ambient temperature. There was a problem that.

[0004]

SUMMARY OF THE INVENTION According to the present invention, in order to solve the above-mentioned problems, a spiral continuous guide groove (groove) meanders in a groove width direction at a constant frequency, and the meandering of adjacent grooves is reduced. The information recording area is always divided into a plurality of zones in the radial direction, and auxiliary information necessary for recording or reproduction including zone identification information is previously recorded between guide grooves (lands). An optical disc recording apparatus for recording a digital information signal on an optical disc, comprising: a reproducing unit for reproducing the auxiliary information recorded between the guide grooves (lands); and a recording position based on the reproduced auxiliary information. Zone identification means for specifying a zone, recording control means for setting conditions for laser irradiation during recording according to the specified zone, and a recording signal recorded on the optical disc A recording state detecting unit for detecting a recording state, a recording correction control unit for correcting the laser irradiation condition according to a detection result of the recording state detecting unit, and a laser according to a laser irradiation condition set by the recording correction control unit. And an optical disk recording device having a laser driving means for driving the optical disk.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The format of the optical disk used in the optical disk recording device of the present invention is as follows. FIG. 1 is an enlarged view of this optical disk. The wobble has a constant angular velocity (CAV: Constant An)
The recording is performed in the same manner as the recording of the digital information, and the phase of adjacent wobbles is always equalized over the area where the digital information is recorded. FIG. 2 is a diagram schematically showing switching of zones. The zones are sequentially divided concentrically from the inner circumference of the disk. FIG. 3 is a diagram showing an example of the content of the land pre-pit signal.

The land pre-pit signal is a zone address,
It consists of a block address, an information signal, and error detection / correction bits. Note that information other than that shown in FIG. 3 can be recorded. The zone address is a bit indicating which zone is the current zone among the division into 0 to N-1. The block address is, for example, a bit indicating which block data corresponds to the current land pre-pit position with respect to digital information divided into error correction blocks. As the additional information signal, information on the disc such as disc identification information and laser pulse irradiation information serving as a reference in each zone is recorded. The error detection / correction bits are redundant bits for detecting and correcting errors in the above information. In the land pre-pit, these information are modulated according to a fixed rule, for example, a 3-bit land pre-pit mark is associated with 1-bit data. Recording is performed according to a modulation method in which land pre-pit marks 1, 0, 0 are applied to data 0.

An embodiment of the optical disk recording apparatus according to the present invention will be described with reference to FIG. First, at the beginning of each zone, a test writing area for obtaining the optimum condition of the recording power for each zone is provided, and the test writing is performed in the following procedure. The signal recorded on the optical disk 1 is detected by the pickup 2 and sent to the wobble detecting device 3 and the pre-pit reproducing device 4. On the other hand, a recording signal is sent from the laser drive circuit 5 to the pickup 2.

[0008] The wobble detection device 3 detects a wobble signal from the reproduced signal. The pre-pit reproducing device 4 separates the pre-pit signal from the reproduced signal based on the reproduced signal output from the pickup 2 and the wobble signal, and detects zone information or recording control information from the pre-pit signal shown in FIG. .

When the reference recording power of the zone is set by the power setting device 6 based on the zone information or the recording control information, the reference recording power is sent to the laser driving circuit 5 together with the recording data pulse-modulated by the pulse generation circuit 7, The laser drive circuit 5 drives the laser so that an optical pulse of the reference power is emitted.

The data recorded by this test writing is reproduced, and the recording state detecting means 8 detects how much the amplitude, symmetry and the like deviate from the proper recording waveform.

FIG. 5 is a diagram showing an example of the recording state detecting means 8. The recording state detection means 8 includes an amplitude and DC level control means 100, an envelope detection means 200, and a shift amount detection means 300. Amplitude and DC
The level control means 100 sets first, second, and third thresholds a, b, and c, and determines the number of times the input waveform crosses each of the thresholds by the threshold a crossing frequency counting means 11
0, the threshold value b cross number counting means 120, and the threshold value c cross number counting means 130, respectively.
0, and the result of the comparison is fed back to the amplifier 170 via the DC control means 150 and the gain control means 160, so that the reproduction amplitude of the input waveform and D
It controls the C level. Regarding the operation and function of the amplitude and DC level control means 100, for example,
It is disclosed in JP-A-2000-200544.
In the amplitude and DC level control means 100, the second threshold value b is set to the zero cross level of the reproduced waveform, the first threshold value a is set to the positive side, and the third threshold value c is set to the negative side. If the value is shifted only by this, the number of times the reproduced waveform crosses the respective thresholds changes depending on the amplitude and the DC level of the input waveform.

As shown in FIG. 6, the input waveform has a threshold value b.
Is greater than the number of times the signal crosses the other threshold value, and the number of times the input waveform crosses the threshold value a is substantially equal to the number of times the input waveform crosses the threshold value c.
By controlling the level, the threshold value b automatically becomes equal to the slice level which is the center value of the amplitude of the shortest recording information reproduction waveform.

In the state where the DC level control is performed, the number of times the input waveform crosses the threshold value b is compared with the number of times the input waveform crosses the threshold value a and the threshold value c. If the gain is adjusted so that the number of times of crossing the threshold value b is slightly increased, the amplitude of the shortest recorded information reproduction waveform automatically changes to the threshold value a and the threshold value c.
Is controlled to be equal to

The reproduced signal controlled by the amplitude and DC level control means 100 is supplied to an envelope detection means 200
Thus, the maximum and minimum points of the maximum amplitude of the reproduction signal are obtained.

The shift amount detecting means 300 includes a threshold a cross number counting means 110, a threshold b cross number counting means 120, and a threshold c cross number counting means 1
The asymmetry, the amount of deviation of the amplitude, and the like are detected from the first, second, and third threshold values a, b, and c, which are the respective count values counted at 30, and the maximum and minimum values of the envelope. Based on this detection result, the laser power correction device 9 adjusts the laser power so as to correct the waveform deviation. In the laser power correction device 9,
Information on the correlation between the intensity of the recording laser power, the symmetry and the deviation of the amplitude is stored in advance, and the correction amount of the laser power is determined from the input deviation amount. This information is sent to the laser drive circuit 5 via the laser power setting device 6, and the laser drive circuit 5 irradiates an optical pulse with an optimum laser power according to the input recording information.

FIG. 7 shows another embodiment of the optical disk recording apparatus according to the present invention. As described above, at the head of the zone, zone information is extracted from the read pre-pit signal, a reference recording pulse shape of the zone is set based on the information, and test writing is performed. The recorded signal is reproduced, and the recording state detection device 8 detects the deviation of the reproduced signal waveform. Based on this result, the pulse shape correction device 9
At 0, correction pulse shape information for adjusting the shape of the recording pulse so as to correct the waveform shift is supplied to the recording pulse shape setting device 91. In the pulse shape correction device 90,
It has information on the correlation between the optical pulse width, symmetry, and amplitude shift in advance, and determines the pulse shape correction amount (correction pulse shape information) based on the input shift amount. Based on this correction amount, the recording pulse shape setting device 91 corrects the reference pulse supplied from the pre-pit reproducing device 4. In accordance with the corrected pulse shape output from the recording pulse shape setting device 91, the data to be recorded is pulse-modulated by the recording pulse generation circuit 7 and sent to the laser drive circuit 5, where the laser drive circuit 5 The laser is driven so that a light pulse is emitted.

FIG. 8 shows an example of recording pulse correction in these embodiments. This is an example showing a change in shape of a recording pulse irradiated in a zone A and a shape of a recording pulse irradiated in another zone B with respect to a mark length to be recorded.

As described above, according to the present invention, the recording conditions (laser irradiation conditions) can be set for each zone and the laser irradiation conditions can be corrected with higher accuracy, so that even under the zone CAV control where the linear velocity changes greatly, Appropriate recording on the phase change recording medium is enabled.

[0019]

As described above, according to the present invention, under the control of the zone CAV (ZCAV) in which the recording frequency is constant for each zone and the shortest recording wavelength is substantially constant between the zones, the recording condition is set to the linear velocity. It is possible to provide an optical disk recording apparatus that enables higher-precision high-density recording on a phase-change recording medium that depends on it.

[0020]

[Brief description of the drawings]

FIG. 1 is a configuration example of a wobble of an optical disc.

FIG. 2 is an explanatory diagram of zones of an optical disc.

FIG. 3 is a signal example of a land pre-pit of an optical disc.

FIG. 4 is a diagram showing an embodiment of the present invention.

FIG. 5 is an explanatory diagram of a recording state detection device according to the present invention.

FIG. 6 is a diagram for explaining an operation of amplitude and DC level control in the present invention.

FIG. 7 is a diagram showing another embodiment of the present invention.

FIG. 8 is a diagram showing an example of a recording pulse correction method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 ... Pickup 3 ... Wobble detection device 4 ... Prepit reproducing device 5 ... Laser drive circuit 6 ... Power setting device 7 ... Pulse generation circuit 8 ... Recording state detection device 9 ... Laser power correction device 90 ... Pulse shape correction device 91 ... Recording pulse shape setting device 100 ... Amplitude and DC level control means 200 ... Envelope detecting means 300 ... Displacement amount detecting means

Claims (3)

[Claims] 1. A spiral continuous guide groove (groove) meanders at a constant frequency in a groove width direction, meandering of adjacent grooves is always in phase, and an information recording area has a plurality of radial recording directions. An optical disc recording apparatus for recording a digital information signal on an optical disc which is divided into zones and in which auxiliary information necessary for recording or reproduction including zone identification information is previously recorded between guide grooves (lands), Reproducing means for reproducing the auxiliary information recorded between the guide grooves (lands); zone identifying means for specifying a zone including a recording position from the reproduced auxiliary information; Recording control means for setting conditions of laser irradiation at the time of recording; recording state detecting means for detecting a recording state of a recording signal recorded on the optical disc; Optical disc recording apparatus having a recording correction control means for correcting the condition of the laser irradiation in accordance with a detection result of means out, and a laser driving means for driving the laser in accordance with the laser irradiation conditions set by the recording compensation control means. 2. The optical disk recording apparatus according to claim 1, wherein said recording correction control means changes a recording laser power value according to a detection result of said recording state detecting means. 3. An optical disk recording apparatus according to claim 1, wherein said recording correction control means changes the shape of an optical pulse irradiated during recording according to the detection means of said recording state detection means.