JP2003006865A - Optical signal recording apparatus and recording compensation method thereof - Google Patents

Abstract

(57) [Problem] To effectively prevent crosstalk and cross-erase between adjacent tracks due to a light spot when data is recorded on a wobbled recording track. When data is recorded, a push-pull error signal is input to a wobble detection circuit from among servo signals obtained by a matrix circuit, and a target for controlling laser power based on the push-pull error signal. The power value is generated by the recording compensation value generation circuit 17. Then, by controlling the laser diode (LD) 6 with this target power value, the target value of the recording power is reduced in the area where the data recording area is narrowed by the wobble shape, and the light beam power is reduced. . Conversely, in a region where data is recorded, the target value of the recording power is increased and the light beam power is increased in a region where the region is widened by the wobble shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical signal recording device for recording various kinds of information on an optical recording medium such as an optical disc, and a recording compensation method therefor.

[0002]

2. Description of the Related Art Conventionally, as an optical signal recording apparatus using an optical disk, various apparatuses for performing both recording and reproduction using a rewritable optical disk such as a magneto-optical (MO) disk or a phase change type disk have been provided. Has been done. In this description, discs of various formats are collectively referred to as an optical disc. Further, such an optical disc has wobbling lands / grooves, and data is recorded while performing tracking servo using the wobble shape of the lands / grooves.

[0003]

By the way, in the above various optical signal recording devices, when the density of the recording signal in the track direction of the optical disc is increased, data interference (crosstalk) between adjacent tracks is caused. It is necessary to prevent damage and destruction (cross write / cross erase), which is an obstacle to high density. For example, in optical modulation recording that outputs modulated light by controlling the on / off of the light source itself,
When recording a long mark, the light spot expands laterally due to the accumulation of heat, and crosstalk and cross erase increase. Also, in magnetic field modulation recording using magneto-optical, a leakage magnetic field becomes large at the time of recording a long mark, and acts as a bias of an applied magnetic field at the time of recording, which hinders good recording.

Therefore, an object of the present invention is to provide an optical signal recording apparatus and a recording compensation method therefor capable of effectively preventing crosstalk and cross erase between adjacent tracks due to an optical spot at the time of recording data on a wobbled recording track. is there.

[0005]

In order to achieve the above object, the present invention provides an optical signal recording apparatus for recording data on an optical recording medium having wobbled recording tracks, for recording data on the optical recording medium. A light source for emitting a light beam, an optical head for recording data on the optical recording medium using the light beam from the light source, and a light beam control means for controlling the recording power of the light beam applied to the optical recording medium. And, when data is recorded on the optical recording medium, a wobble shape detection means for detecting a wobble shape of a region where data is recorded, and the light beam control means based on a detection signal by the wobble shape detection means. And a recording compensating means for changing the target value of the recording power in. Further, the present invention relates to a recording compensation method of an optical signal recording device for recording data on an optical recording medium having a wobbled recording track, wherein when recording data on the optical recording medium, wobble of an area where data is recorded is recorded. The shape is detected, and the target value of the recording power in the light beam control for recording the data on the optical recording medium is changed based on the detection signal.

In the optical signal recording apparatus of the present invention, when data is recorded on the optical recording medium, the wobble shape detecting means detects the wobble shape of the area where the data is recorded, and based on this detection signal, recording is performed. The compensating means changes the target value of the recording power in the light beam control means.
Therefore, in the area where the data recording area is narrowed due to the wobble shape, the target value of the recording power is lowered, the light beam power is reduced, and conversely the data recording area is widened due to the wobble shape. In the area, the target value of the recording power is increased and the light beam power is increased. As a result, data can be recorded with the light beam power adapted to the wobble shape, and crosstalk or cross erase between adjacent tracks due to the spread of the light spot can be effectively prevented.

In the recording compensation method of the optical signal recording apparatus of the present invention, when data is recorded on the optical recording medium, the wobble shape of the area where the data is recorded is detected, and the light beam is detected based on this detection signal. The target value of the recording power in the control means is changed. Therefore, in the area where the data recording area is narrowed due to the wobble shape, the target value of the recording power is lowered, the light beam power is reduced, and conversely the data recording area is widened due to the wobble shape. In the area, the target value of the recording power is increased and the light beam power is increased. As a result, data can be recorded with the light beam power adapted to the wobble shape, and crosstalk or cross erase between adjacent tracks due to the spread of the light spot can be effectively prevented.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an optical signal recording apparatus and a recording compensation method thereof according to the present invention will be described below. The embodiments described below are preferred specific examples of the present invention, and various technically preferable limitations are given. However, the scope of the present invention is not limited to the present invention in the following description. Unless otherwise stated, the present invention is not limited to these embodiments.

FIG. 1 is a block diagram showing the overall configuration of an optical signal recording device according to the present invention. As shown in the figure, this optical signal recording device includes an optical disc 1, a spindle motor 2,
Objective lens 3, beam splitters 4, 7, collimator lens 5, laser diode (LD) 6, photodetection lenses 8A, 8B, photodetectors (PD) 9A, 9B, F
APC (Front Auto Power Control) photodetector 10, IV converter 11, matrix circuit 12, wobble detection circuit 13, phase compensation circuit 14, biaxial drive circuit 1
5, magnetic head drive circuit 16, recording compensation value generation circuit 1
7, a data binarization unit 18, a phase error detection unit 19, a timing generation unit 20, a power control circuit 21, and a laser drive circuit 22.

When recording data, the optical signal recording apparatus according to the present embodiment inputs a push-pull error signal from the servo signals obtained by the matrix circuit 12 to the wobble detection circuit 13, and outputs this push-pull error signal. A target power value for controlling the laser power is generated by the recording compensation value generation circuit 17 based on this, and the laser diode (LD) 6 is controlled by this target power value to record the data (in this example In the area where the land) is narrowed due to the wobble shape, the target value of the recording power is lowered, the light beam power is reduced, and conversely the area where data is recorded (land in this example)
The target value of the recording power is increased and the light beam power is increased in the area widened by the wobble shape. As a result, data can be recorded with a light beam power adapted to the wobble shape, and crosstalk between adjacent tracks and cross erase due to the spread of the light spot can be effectively prevented.

The other constitution is basically the same as that of the conventional one, but the outline thereof is as follows.
The laser light emitted from the laser diode (LD) 6 is supplied to the signal recording surface of the optical disc 1 through the collimator lens 5, the beam splitter 4, and the objective lens 3. Then, the laser light reflected by the signal recording surface of the optical disc 1 is split by the beam splitters 4 and 7, and a light detection lens 8 including a cylindrical lens and the like is provided.
Photodetector (PD) 9A, 9B through A, 8B
Is received by. The detection current signals from the photodetectors (PD) 9A and 9B are converted into detection voltage signals by the IV conversion unit 11 and input to the matrix circuit 12.
The matrix circuit 12 generates an MO signal, a focus error (FE) signal, a tracking error (TE) signal, etc. from the input detection voltage signal.

The tracking error signal includes a push-pull error signal (PushPull), and as described above, the wobble shape is detected using the push-pull error signal. The push-pull error signal is obtained, for example, by detecting the reflected light from the optical disc 1 in a light receiving region that is divided into two in the radial direction of the optical disc 1, and taking the difference between the detection signals from the respective light receiving regions. Represents the amount of positional deviation of the light spot with respect to the radial direction. Therefore, if the state of the reflected light of the light beam changes due to the wobble shape of the data recording area, the difference in the received light amount of the reflected light in each of the divided light receiving areas changes, and this is reflected in the push-pull error signal. It is possible to detect the wobble shape from the fluctuation of the push-pull error signal.

Instead of such a push-pull error signal, it is also possible to use, for example, a sum signal (Pull In) which is the sum of the amounts of light received by the light receiving elements. That is, since the amount of the entire reflected light varies depending on the wobble shape, the wobble shape can be detected also by the sum signal. However, when the sum signal is used, the sum signal itself directly fluctuates due to the control of the target power value of the laser light, and thus it is necessary to perform control processing in consideration of this fluctuation. In this respect, since the push-pull error signal is a differential signal, the influence of the fluctuation of the target power value of the laser light is small,
There is an advantage that stable control can be performed with a simpler configuration.

The push-pull error signal generated by the matrix circuit 12 is converted into a wobble signal corresponding to the wobble shape by the wobble detection circuit 13 and input to the recording compensation value generation circuit 17 and the timing generation section 20. The recording compensation value generation circuit 17 generates a target power value signal of the laser light based on the wobble signal, and supplies this to the power control circuit 21. The power control circuit 21 is
Based on the target power value signal obtained from the recording compensation value generation circuit 17 and the laser power detection signal obtained from the FAPC photodetector 10, the output of the laser diode (LD) 6 matches the target power value. The laser drive circuit 22 is controlled.

The timing generator 20 generates a timing signal for performing a recording operation based on the wobble signal, and supplies this to the magnetic head drive circuit 16, the data binarizer 18, and the phase error detector 19. Objective lens 3
Is mounted on a biaxial actuator (not shown) and is servo-controlled by the biaxial drive circuit 15 in the focus and tracking directions. The magnetic head driving circuit 15 applies a magnetic field to the optical disc 1 via the magnetic head 15A to record data on the optical disc 1 by a magneto-optical recording method.

Next, details of the recording compensation method in the optical signal recording apparatus having the above-mentioned structure will be described. Figure 2
FIG. 4 is a diagram for explaining specific contents of recording compensation in the optical signal recording apparatus of this example, and FIG. 2 shows before and after compensation when an optical spot tracks a recording track (land in this example). It is a top view which compares and shows a state. FIG. 3 is an explanatory diagram showing the relationship between the recording (writing) power and the jitter before and after compensation. Furthermore, FIG.
6 is a timing chart showing how a target power value signal is generated from a push-pull error signal. Although FIG. 2 shows that the spot diameter of the light beam changes due to the recording compensation of this example, the spot diameter itself does not actually change optically, but the recording power of the light beam changes. 2 changes, and FIG. 2 shows an image of this change in recording power by a change in spot diameter.

As shown in FIG. 2B, since recording is performed with a constant light beam power in the state before compensation,
At a position where the recording area is narrowed by wobbling (position B), a part of the light spot protrudes to an adjacent track, which causes crosstalk or cross write. For this reason, as shown in FIG. 3B, the amount of jitter at the B position is sharply increased as the recording power is increased, as compared with the amount of jitter at a wide recording region (position A). . Therefore, in the optical signal recording apparatus of the present example, as shown in FIG. 2A, by performing the recording compensation process for controlling the recording power according to the wobble shape, as shown in FIG. The variation of the jitter amount with respect to the recording power at the position is controlled so as to be equal to the position A, and a stable recording operation is realized.

Further, as shown in FIGS. 3 (a) and 3 (b), a push-pull signal corresponding to the wobble shape of the land portion is detected, and the push-pull signal is subjected to a certain signal processing, so that FIG. A target power value signal as shown in can be obtained. In this type of optical signal recording device, since the frequency of the wobble waveform is several tens of kHz and the frequency of servo control is several kHz, the recording power control of the laser light corresponding to the wobble shape is performed by the reflected light of the laser light. Can be realized without affecting the servo control by. Further, in the present example, the present invention has been described with respect to the optical signal recording device by the magneto-optical recording system. That is, in the magneto-optical recording method, since the recording state in the mark length direction is mainly determined by the magnetic field strength, even when the power of the laser light is changed by the recording compensation method of this example, It has no influence on the recording state of the recording medium, and it is possible to control so that only the mark width is enlarged or reduced. Therefore,
Even when the recording compensation method of this example is applied, there is an advantage that it can be applied without affecting the reading accuracy of the mark length during data reproduction.

However, the present invention can be applied not only to the optical signal recording apparatus of the magneto-optical recording system but also to the optical signal recording apparatus of the optical modulation recording system. That is, in the optical modulation recording method, the fluctuation of the recording power by the recording compensation method of this example has a certain influence on the recording state of the data in the mark length direction, but it is ignored in the actual reproducing operation. Since the influence is as much as possible, it can be applied in the same manner as the above example.

[0020]

As described above, in the optical signal recording apparatus of the present invention, when recording data on the optical recording medium, the wobble shape detecting means detects the wobble shape of the area where the data is recorded, The recording compensation means changes the target value of the recording power in the light beam control means based on the detection signal. Therefore, it is possible to record data with an optical beam power adapted to the wobble shape, effectively prevent crosstalk and cross erase between adjacent tracks due to the spread of the optical spot, and realize highly reliable signal recording. It is also possible to contribute to high density recording.

Further, in the recording compensation method of the optical signal recording apparatus of the present invention, when data is recorded on the optical recording medium, the wobble shape of the area where the data is recorded is detected, and the optical signal is detected based on this detection signal. The target value of the recording power in the beam control means is changed. Therefore, it is possible to record data with an optical beam power adapted to the wobble shape, effectively prevent crosstalk and cross erase between adjacent tracks due to the spread of the optical spot, and realize highly reliable signal recording. It is also possible to contribute to high density recording.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an optical signal recording device according to an embodiment of the present invention.

FIG. 2 is a plan view showing a state before compensation and a state after compensation when an optical spot tracks a recording track in the optical signal recording device shown in FIG.

FIG. 3 is an explanatory diagram showing a relationship between recording power and jitter before and after compensation in the optical signal recording device shown in FIG.

FIG. 4 is a timing chart showing how a target power value signal is generated from a push-pull error signal in the optical signal recording device shown in FIG.

[Explanation of symbols]

1 ... Optical disc, 2 ... Spindle motor, 3 ... Objective lens, 4, 7 ... Beam splitter, 5 ... Collimator lens, 6 ... Laser diode (LD), 8A,
8B ... Condensing lens, 9A, 9B ... Photodetector (PD), 11 ... IV converter, 12 ... Matrix circuit, 13 ... Wobble detection circuit, 14 ... Phase compensation circuit, 15 ... Biaxial drive Circuit: 16 ... Magnetic head drive circuit, 17 ... Recording compensation value generation circuit, 18 ... Data binarization unit, 19 ... Phase error detection unit, 20 ... Timing generation unit, 21 ... Power control circuit, 22 ... Laser drive circuit.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G11B 11/105 556 G11B 11/105 556C F term (reference) 5D075 AA03 BB04 CC01 CD11 EE03 FG18 5D090 AA01 BB05 BB10 CC01 DD03 EE02 FF45 GG03 KK03 5D118 BA01 BB06 BC08 BF03 CA13 5D119 AA14 BA01 BB03 DA01 EC12 HA23 HA45

Claims (10)

[Claims] 1. An optical signal recording device for recording data on an optical recording medium having wobbled recording tracks, wherein a light source for emitting a light beam for recording data on the optical recording medium, and a light beam from the light source An optical head for recording data on the optical recording medium using, a light beam control means for controlling the recording power of a light beam applied to the optical recording medium, and when recording data on the optical recording medium, Based on the wobble shape detection means for detecting the wobble shape of the area where data is recorded, and the detection signal by the wobble shape detection means,
An optical signal recording apparatus comprising: a recording compensating unit that changes a target value of the recording power in the light beam control unit. 2. The optical signal recording device according to claim 1, wherein the wobble shape detecting means detects a wobble shape from a servo error signal used for tracking servo of the optical head. 3. The servo error signal detects reflected light from an optical recording medium by a photodetector having a light receiving region divided in a radial direction of the optical recording medium, and a difference between detection signals from the respective light receiving regions is detected. The optical signal recording device according to claim 2, wherein the optical signal recording device is a push-pull error signal obtained by taking the above. 4. The recording compensator reduces the target value of the recording power in an area where the data recording area is narrowed due to the wobble shape, and the recording area is widened due to the wobble shape. 2. The optical signal recording device according to claim 1, wherein the target value of the recording power is changed so as to increase the target value of the recording power in the area. 5. The recording method for recording data on the optical recording medium is a magneto-optical recording method.
The optical signal recording device described. 6. A recording compensation method of an optical signal recording device for recording data on an optical recording medium having wobbled recording tracks, wherein wobble of an area where data is recorded is recorded when the data is recorded on the optical recording medium. Recording compensation of an optical signal recording device, characterized in that a target value of a recording power in a light beam control for recording data on the optical recording medium is changed based on a detection signal of the shape. Method. 7. The recording compensation method for an optical signal recording apparatus according to claim 6, wherein the wobble shape is detected from a servo error signal used for tracking servo of the optical head. 8. The servo error signal is obtained by detecting the reflected light from the optical recording medium with a photo-detecting element having a light-receiving area divided in the radial direction of the optical recording medium, and calculating the difference between the detection signals from the respective light-receiving areas. 8. The recording compensation method for an optical signal recording device according to claim 7, wherein the push-pull error signal is obtained by taking the above. 9. The target value of the recording power is lowered in an area where the data recording area is narrowed due to the wobble shape, and the recording power is decreased in the area where the data recording area is widened due to the wobble shape. 7. The recording compensation method for an optical signal recording apparatus according to claim 6, wherein the target value of the recording power is changed so as to increase the target value. 10. The recording compensation method for an optical signal recording device according to claim 6, wherein the recording method for recording data on the optical recording medium is a magneto-optical recording method.