JPH10222844A - Method and device for recording optical recording medium, and optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the fluctuation of recording signals and to suppress jitters to a lower level by conducting a recording compensation in accordance with the fluctuation of guide groove tracking signals while recording signals to the optical recording medium which selects a wobble system. SOLUTION: The compensation condition of the recording optical intensity, which corresponds to the fluctuation of the guide groove tracking signals, is determined by beforehand surveying the relationship between the recording optical intensity and data signal amplitudes and the relationship between the guiding groove tracking signals and the data signal amplitudes. By employing the determined compensation condition, the recording optical intensity is made stronger at the portion, where the deviation between the guide grooves and the position of an optical spot is large, and the data signals having no amplitude fluctuation are recorded. When the compensation condition of the recording optical intensity corresponding to the fluctuation of the guiding groove tracking signals is not known beforehand, a recording test is conducted prior to the recording of user data or the compensation condition is recorded beforehand on an optical recording medium and the condition is determined by reading the condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium recording method, a recording apparatus, and an optical recording medium. For more information,
The present invention relates to a recording method, a recording apparatus, and an optical recording medium for an optical recording medium that correct recording conditions according to a change in a guide groove tracking signal.

[0002]

2. Description of the Related Art Conventionally, as an optical recording medium, grooves and pits for recording information and tracking an optical spot for reproducing the recorded information are previously formed on a substrate by means of a press or the like. On the surface where this pit was formed, A
A read-only optical recording medium in which a light reflecting layer made of a metal film of u, Al or the like is formed, and a protective layer made of a photocurable resin is further formed thereon has been put to practical use. Above all, compact discs (CDs) are widely used for storing and reproducing music, images, data, programs and the like. The specification concerning the recording and reproduction signals of this CD is IEC9
08 or JIS-S-8605 standard, and playback devices conforming to this standard are widely used as CD players. Recently, a high-density optical recording medium called a DVD having a similar configuration and having a capacity approximately seven times as large as a CD has been put into practical use.

On the other hand, by irradiating a laser beam,
A so-called recordable optical recording medium on which data can be freely recorded is also known. For such a recordable optical recording medium, various systems such as magneto-optical recording, phase change recording, and recording by decomposition of a dye have been proposed and put into practical use. In these recordable optical recording media, usually, a signal indicating position information on the optical recording medium and a signal for rotation control are recorded in advance. As one of means for recording such information, there is a method of changing the position of a guide groove for tracking a light spot in a direction perpendicular to the traveling direction of the light spot.
No. 374, 1987-59373, published patent application 1988-103454 and others. An example of such a guide groove is shown in FIG. The position fluctuation of the guide groove can be read from a signal for tracking the guide groove (also referred to as a tracking error signal).
The principle will be described below.

Usually, a recording / reproducing apparatus for an optical recording medium includes:
Control means for moving the light spot along the guide groove is provided. By this means, it is possible to record information at high density on the optical recording medium and to reproduce the information even when there is a vibration of the apparatus or a large displacement between the guide groove and the light spot. Become. For example, when a guide groove is formed substantially concentrically on a disc-shaped optical recording medium (optical disk), there is a deviation between the center of the guide groove circle and the rotation center of the optical disk, and the guide groove is eccentric. The light spot can be made to follow the fluctuation of the guide groove even in the case of rotating with the angle, so that information can be recorded and reproduced. In order to perform such control, it is necessary to detect a deviation between the position of the light spot and the position of the guide groove and to detect a signal for tracking the guide groove (a so-called tracking error signal).
Various methods for detecting such a signal, such as a push-pull method and a three-beam method, have been proposed. The position of the light spot is controlled to track the guide groove so that the value of this signal becomes a value (normally 0) when the light spot is at the center of the guide groove. Therefore, when the light spot is accurately tracking on the guide groove, no change is seen in the tracking error signal.

Usually, the frequency of the deviation between the guide groove and the light spot (that is, the fluctuation of the guide groove when the light spot is fixed) is several kHz or less, and the mechanism for following the guide groove has a higher frequency. It is designed not to respond to fluctuations. Therefore, when the guide groove is slightly changed at a frequency of several kHz or more, the light spot can no longer follow the change in the guide groove, and a change in the tracking error signal due to this change is observed. Therefore, the guide groove is several k
If the frequency is changed at a frequency equal to or higher than Hz and a modulation signal is recorded using the change, position information (address) can be recorded in the tracking error signal. Further, if the frequency of the fluctuation of the guide groove is kept constant, the optical recording medium can be moved so that a constant frequency is observed. For example, it is possible to control the rotation speed of the optical disk.

In such a method of recording the position information and the rotation control signal based on the tracking error signal, it is not necessary to provide a recording area for the position information and the rotation control information on the optical recording medium. Can be used for recording / reproducing user data, and is suitable for a large-capacity optical recording medium. This method will be referred to as the wobble method hereinafter. However, when the wobble method is applied to an optical recording medium, there is a problem that a recording signal of user data is disturbed, a jitter of the recorded signal is increased, and a reading error rate is increased. In particular, such a phenomenon often becomes remarkable in an optical recording medium on which information is recorded at a high density.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a guide groove for tracking a light spot which has a slight positional change in the direction perpendicular to the traveling direction of the light spot and which has substantially no change in shape. An optical recording medium having a formed substrate, capable of recording information, capable of recording a user data signal with no disturbance and low jitter, and preventing an increase in an error rate, a recording method, and It is to provide a recording device.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, an increase in the jitter of the recording signal in the wobble method is caused by the fact that the light spot is on the guide groove during recording. And that the difference is caused in the recorded data signal when the light spot deviates from the guide groove, and in many cases, the amplitude of the data signal becomes small when the light spot deviates from the guide groove. I found something. Furthermore, it has been found that the rise in jitter can be prevented by detecting the shift between the light spot and the guide groove and correcting the recording conditions in accordance with the shift, thereby completing the present invention.

That is, the present invention includes a substrate having a guide groove for tracking a light spot which has a slight positional change in a direction perpendicular to the traveling direction of the light spot and whose shape does not substantially change. A method for recording information on an optical recording medium capable of recording information, wherein a fluctuation appearing in a signal for tracking the guide groove is observed, and the recording condition is corrected accordingly. The recording method of recording a recording test before actually recording the information signal, and determining the correction condition of the recording condition due to the fluctuation of the guide groove tracking signal, and reading the information recorded on the optical recording medium in advance And a recording method for determining a correction condition of a recording condition due to a change in a guide groove tracking signal.

Further, the present invention includes a substrate having a guide groove for tracking a light spot which has a slight positional change in a direction perpendicular to the traveling direction of the light spot and whose shape does not substantially change. A device for recording information on an optical recording medium capable of recording information, comprising: means for observing a change in a signal for tracking the guide groove; and means for correcting a recording condition according to the change in the signal. A recording device for performing a recording test for determining a correction condition of a recording condition due to a change in a guide groove tracking signal before actually recording an information signal; The present invention relates to a recording apparatus for reading information on a correction condition of a recording condition due to a change in a guide groove tracking signal recorded on a medium.

Still further, the present invention provides a substrate having a light spot tracking guide groove which has a slight positional change in a direction perpendicular to the light spot traveling direction and whose shape does not substantially change. In an optical recording medium capable of recording information, an area for a recording test for determining a correction condition of a recording condition due to a fluctuation of a guide groove tracking signal is provided before actually recording an information signal. An optical recording medium characterized in that a correction condition of a recording condition due to a change in a guide groove tracking signal is recorded in advance in an area for a recording test.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 is a diagram illustrating the principle of the present invention. a is a guide groove viewed from above the optical recording medium,
b is the fluctuation of the guide groove tracking signal, c is the fluctuation of the amplitude of the data signal when recorded at a constant recording light intensity, d is an example of a method of correcting the recording light intensity, and e is the value after performing the recording correction. Each state of a data signal is shown.

(A) of FIG. 1 is an example of a guide groove which has a slight positional change in the direction perpendicular to the traveling direction of the light spot and whose shape does not substantially change. It is the enlarged view which looked at. The magnitude of the fluctuation of the position of the guide groove is
Usually, it is about 30% to 0.05% of the track pitch, more preferably about 10% to 0.1%. The frequency of the fluctuation of the guide groove following signal due to this fluctuation is not particularly limited as long as the guide groove following mechanism of the light spot does not respond at the normal moving speed of the light spot. Therefore, the light spot moves not on the guide groove but on the center line of the guide groove. In such a case,
A shift occurs between the position of the guide groove and the position of the light spot, and a change as shown by b in FIG. 1 also appears in the guide groove follow-up signal in accordance with the change in the position of the guide groove.

When data is recorded on this optical recording medium at a constant recording light intensity and reproduced, a signal as shown at c in FIG. 1 is obtained. As can be seen from this figure, the amplitude of the data signal decreases as the position of the guide groove moves away from the center line of the guide groove, that is, as the light spot moves away from the guide groove. As described above, when the amplitude of the reproduced signal fluctuates, the jitter of the recorded data signal increases. Various methods can be considered to prevent such a change in the data signal, but the simplest method is to correct the recording light intensity. Generally, the amplitude of a recorded data signal increases as the recording light intensity increases. By examining in advance the relationship between the recording light intensity and the data signal amplitude, and further the relationship between the guide groove following signal and the data signal amplitude, it is possible to determine the correction condition of the recording light intensity according to the fluctuation of the guide groove following signal. By using the correction conditions determined in this way, the recording light intensity is increased at the portion where the position of the guide groove and the light spot is largely shifted, as shown at d in FIG.
Thus, a data signal having no fluctuation in amplitude can be recorded.

If the correction condition according to the fluctuation of the guide groove following signal is not known in advance, a recording test is performed before recording the user data, or the correction condition is recorded in advance on an optical recording medium. In advance, it is effective to determine the correction condition by reading it. A specific method of the recording test is, for example, as follows. First, record data signals under certain recording conditions,
Measure the variation of the data signal amplitude. Next, recording is performed under arbitrary correction conditions according to the guide groove following signal, and the fluctuation of the data signal amplitude is measured in the same manner. The fluctuations in the data signal amplitudes are compared with each other, the correction conditions are reset so that the data signal amplitude fluctuations become smaller, the data signal is recorded, and the data signal amplitude fluctuations are measured. By repeating this procedure until the data signal amplitude fluctuation becomes smaller than a preset upper limit reference, an optimum correction condition can be determined. In this case, it is necessary to provide an area for performing a recording test on the optical recording medium. As a method of recording the correction condition in the optical recording medium, the correction condition may be recorded as data by pre-pits, or may be recorded by using various modulation methods during the change of the guide groove using the change of the guide groove following signal. May be. In any case, the recording apparatus for the optical recording medium may read these recorded correction conditions and perform recording according to the read correction conditions.

FIG. 3 is an explanatory view of an example of a recording apparatus for an optical recording medium according to the present invention. Light emitted from the optical head is focused on a minute light spot on the optical recording medium. The optical head also receives reflected light from the optical recording medium and generates a data signal and a guide groove following signal. The guide groove follow-up signal is used in a normal guide groove follow-up control system, and is also sent to a recording correction circuit, which measures the fluctuation of the guide groove follow-up signal, and operates the recording circuit under a correction condition corresponding to the guide groove follow-up signal. Drive. Thus, the recording method of the present invention is realized.
In order to perform a recording test, a signal source for recording test, a recording signal fluctuation measuring circuit, and an arithmetic circuit for determining correction conditions may be added to FIG. In order to read the recording correction condition from the optical recording medium, a correction condition reading circuit may be added and the correction condition may be read from the data signal or the guide groove following signal.

[0017]

EXAMPLES Hereinafter, an example of the present invention will be described in detail, but embodiments of the present invention are not limited thereto. Example 1 By injection molding, a guide groove having a position variation equivalent to 2% of the track pitch in a direction perpendicular to the traveling direction of a light spot and having a diameter of 120 m onto which a guide groove whose shape does not change was transferred.
m, a transparent polycarbonate substrate having a thickness of 0.6 mm was produced. At this time, the track pitch was 0.74 μm, and the width and depth of the guide groove were 0.27 μm and 120 nm, respectively. On this substrate, a recording layer made of an Ni complex of an azo dye represented by the following formula (1) (Formula 1) was formed, and a reflective layer made of Au was further formed thereon. The reflective layer side of this medium and another transparent polycarbonate protective substrate having a diameter of 120 mm and a thickness of 0.6 mm are bonded together with an adhesive to form an optical recording medium having a cross-sectional structure as shown in FIG. Produced.

[0018]

Embedded image Light having a wavelength of 635 nm was applied to the optical recording medium thus manufactured at a recording light intensity of 8 mW and the moving speed of the light spot was 3.49.
Data was recorded while rotating the disk so that the speed became m / s. At this time, the recording light is adjusted according to the correction condition of the recording light intensity according to the fluctuation of the guide groove following signal, which is determined in advance by examining the relationship between the recording light intensity and the data signal amplitude, and further the relationship between the guide groove following signal and the data signal amplitude. Recording was performed while changing the intensity. As a result, the jitter value could be reduced by 20% as compared with the case where such correction was not performed.

[0019]

According to the present invention, when a signal is recorded on an optical recording medium employing the wobble method, the recording signal is corrected in accordance with the fluctuation of the guide groove tracking signal, so that the fluctuation of the recording signal is reduced. This reduces the jitter, lowers the jitter, and prevents an increase in the error rate.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory diagrams of the principle of the present invention. FIG. 1A shows a change in the position of a guide groove, FIG. 1B shows a change in a guide groove tracking signal, and FIG. To d
Represents an example of a method of correcting the recording light intensity, and e represents a state of the data signal after performing the recording correction.

FIG. 2 is an explanatory diagram of a cross-sectional structure of an optical recording medium used in an example.

FIG. 3 is an explanatory diagram of an example of a recording device for an optical recording medium according to the present invention.

[Explanation of symbols]

1: Guide groove 2: Center line of guide groove 3: Guide groove follow-up signal 4: Data signal when recording is performed at a constant recording light intensity 5: Recording light intensity after correction 6: Data signal when recording is corrected 21: Substrate 22: Recording Layer 23: Reflective Layer 24: Adhesive Layer 25: Protective Substrate 31: Optical Recording Medium (Optical Disk) 32: Optical Head 33: Variation Measurement Circuit of Guide Groove Tracking Signal and Recording Correction Circuit 34: Recording Light Intensity control circuit 35: Guide groove tracking control circuit 36: Guide groove tracking device 37: Data signal processing circuit 38: Disk rotating device 39: Guide groove tracking signal 40: Data signal

Claims (8)

[Claims] 1. In a direction perpendicular to a traveling direction of a light spot,
A method of recording information on an optical recording medium capable of recording information, the substrate having a guide groove for tracking an optical spot having a slight change in position and having substantially no change in shape. A recording method for an optical recording medium, characterized by observing a fluctuation appearing in a signal for tracking a guide groove and correcting a recording condition according to the fluctuation. 2. The recording method according to claim 1, wherein a recording test is performed before recording the information signal, and a correction condition of the recording condition due to a change in the guide groove tracking signal is determined. 3. The recording method according to claim 1, wherein information recorded in advance on an optical recording medium is read to determine a correction condition of a recording condition due to a change in a guide groove tracking signal. 4. In a direction perpendicular to the traveling direction of the light spot,
An apparatus for recording information on an optical recording medium capable of recording information, having a substrate on which a guide groove for tracking an optical spot having a slight change in position and having substantially no change in shape is provided. A recording apparatus for an optical recording medium, comprising: means for observing a change in a signal for tracking a guide groove; and means for correcting a recording condition according to the change in the signal. 5. A recording device for performing a recording test for determining a correction condition of a recording condition due to a change in a guide groove tracking signal before recording an information signal.
The recording device according to claim 1. 6. A system according to claim 4, further comprising means for reading information on a correction condition of a recording condition due to a change in a guide groove tracking signal, which is recorded in advance on an optical recording medium.
The recording device according to claim 1. 7. In a direction perpendicular to the traveling direction of the light spot,
Before recording an information signal on an optical recording medium capable of recording information, having a substrate with a guide groove for light spot tracking having a slight change in position and having substantially no change in shape, An optical recording medium having a recording test area for determining a recording condition correction condition based on a change in a guide groove tracking signal. 8. The optical recording medium according to claim 7, wherein a correction condition of a recording condition due to a change in a guide groove tracking signal is recorded in an area for a recording test in advance.