JPH07121891A - Device for recording/reproducing optical information - Google Patents

Abstract

PURPOSE:To record/reproduce both recording systems of land/groove by reading out a control track with a tracking signal of one side polarization and reading out it by inverting the polarization when no address is detected surely. CONSTITUTION:By a controller 8, an optical disk 1 is rotated, and the focusing control and the tracking control are performed, and the address is detected with an output signal from a data demodulation circuit 5. When the address is detected correctly, an optical pickup 3 is sought, and a control track is reproduced. On the other hand, when no address is detected, by the controller 8, a polarization inversion circuit 7 is controlled, and the polarization of the tracking signal is inverted. Then, the tracking control is performed again, and the address is reproduced, and the control track is reproduced. Thus, without providing a special senser, both systems are reproduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to tracking control in an optical disk device, and in particular, land recording is possible even for different kinds of disks having no great difference in reflectance without the need of using a special optical sensor or the like. The present invention relates to an optical information recording / reproducing apparatus capable of performing a recording / reproducing operation corresponding to both recording systems by making it possible to discriminate between the recording system and the groove recording system.

[0002]

2. Description of the Related Art Conventionally, there are two types of recording methods for optical disks, a land recording method and a groove recording method. In general, an optical disc called MO uses a land recording system as a mainstream, but a disc using a phase change recording material (so-called PC) also has a groove recording system.

FIG. 4 is a diagram for explaining the states of the address area and the data area on the track for the land recording method and the groove recording method. (1) shows the land recording method and (2) shows the groove recording method. The center of the drawing is a front view of the address area and the data area, the upper part thereof is a disk sectional view taken along the line A of the address area, and the lower part thereof is a disk sectional view taken along the line B of the data area.

As shown in FIGS. 4 (1) and 4 (2), a groove is formed in the address area and the data area on the track.
And a land (between the grooves) are formed. First, in the case of the land recording method, as shown in the center and the upper part of FIG. 4 (1), the land portion is arranged in the center of the address signal (address area) along the track length direction. The groove portions are arranged on both sides of the groove portion.

In the land recording method, as shown in FIG.
As shown in the center of (1), the address signal (address area) is recorded by forming pits in the land portion. As shown in the center and lower part of FIG. 4 (1), the data area extends along the track length direction.
A land portion is provided in the center.

On the other hand, in the case of the groove recording system, FIG.
As shown in the center and upper part of (2), along the length direction of the track, a groove is arranged in the center and lands are arranged on both sides of the groove. With this groove recording method,
As shown in the center of FIG. 4 (2), the address signal (address area) is recorded by the intermittent groove.

Therefore, the tracking signals for controlling the light spot are different between these two recording methods. Next, with respect to tracking control, the principle of the push-pull method will be described.

FIG. 5 is a diagram showing the principle of the push-pull method used in the optical information recording / reproducing apparatus and an S-shaped curve of the tracking error amount. (1) is in a state of being coincident with a track, (2)
Indicates a track deviation state, and (3) indicates an S-shaped curve. In the figure, 2D-PD is a two-divided light receiving element, OL is an objective lens, and DIS is a disc.

The push-pull method is also called the far-field method, and the light reflected and diffracted by the guide groove on the disc DIS is divided into two light-receiving elements 2D-PD arranged symmetrically with respect to the track center. This is a method of detecting a tracking error by taking out as an output difference in the light receiving section. That is, as shown in FIG. 5 (1), when the center of the light spot and the guide groove (groove portion) or the center of the middle portion of the light spot, the guide groove, and the guide groove are coincident with each other, they are symmetrical. A reflected diffracted light distribution is obtained, and in other cases, the light intensity is deviated between the left and right as shown in FIG. 5 (2).

As a result, when the light spot crosses the track, the output difference between the two light receiving portions on the two-divided light receiving element 2D-PD becomes an S-shaped curve as shown in FIG. 5 (3). In FIG. 5 (3), the horizontal axis indicates the center position of the spot. For example, at the center of the groove portion or land portion, the tracking error signal (amplitude of the S-shaped curve) becomes zero, and one end of the groove portion appears. Has a maximum value in the negative direction, and has a maximum value in the positive direction at the boundary between the groove portion and the land portion.

Therefore, the center of the light spot can be detected by the tracking error signal, and the light spot can be irradiated to a desired position on the disc DIS by the tracking control. The push-pull method is a tracking control method that controls the irradiation position of a light spot based on such a principle.

As described above with reference to FIGS. 5 (1) to 5 (3), the polarities of the tracking signals are opposite between when tracking control is performed on the groove and when tracking control is performed on the land. In the conventional apparatus, the spot position on the track corresponding to each recording method is controlled by the push-pull method or the like to perform the information recording / reproducing operation.

For example, an optical information recording / reproducing apparatus compatible with two conventional recording systems discriminates the type of the optical disc based on the information previously recorded on the control track of the optical disc, and determines the type of the disc. An apparatus for recording information under such driving conditions has been proposed (for example, Japanese Patent Laid-Open No. 2-308425). With this device,
In order to discriminate the type of disc, it is necessary to read the information recorded in advance on the control track, but the control track has the same information as the address signal described above (here, information such as driving conditions). Is also recorded.

However, since the data recording principle and conditions are different between MO (magneto-optical disk) and PC (disk using a phase change recording material), which type of drive is used? It is necessary to determine if there is. In this case, for example, MO is a land recording system, PC
If it is a groove recording method, only the control track of one of the recording methods can be read, and as a result, the conventional drive can record and reproduce only the disc of one recording method decided at the time of design. There is a problem that you cannot do it.

There is also proposed a device for discriminating between reproduction-only / write-once / rewritable type depending on the difference in reflectance of the optical disk (for example, Japanese Patent Laid-Open No. 3-116442). The discriminating method in this case is performed by reading a special repeating pattern provided on the inner or outer circumference of the disc with an optical sensor provided on the inner or outer circumference.

However, the method of discriminating the type of the disc based on the change of the reflectance as described above has a problem that there is no great difference in the reflectance and discs of different types cannot be discriminated. Furthermore, a special optical sensor or the like is also required, which is an obstacle to downsizing / price reduction of the device.

[0017]

SUMMARY OF THE INVENTION According to the present invention, there are inconveniences that occur in the conventional optical information recording / reproducing apparatus, that is,
Since the polarities of the tracking signals are different between the land recording method and the groove recording method for the optical disc, a special optical sensor is required to identify the recording method, and the type is determined by the difference in the reflectance of the optical disc. This method solves the inconvenience that discs of different types cannot be distinguished because there is no great difference in reflectance, and there is no need to install a special optical sensor, etc. It is also an object of the present invention to provide an optical information recording / reproducing apparatus capable of discriminating the recording system (land / groove) and enabling a recording / reproducing operation corresponding to a disc of both recording systems.

[0018]

According to the present invention, firstly,
In an apparatus for recording / reproducing information by condensing a laser beam in a spot shape along the guide groove on an optical recording medium provided with a guide groove in advance, the recording medium is reflected on the recording medium by reflected light from the recording medium. Information reproducing means for reproducing recorded information; track signal detecting means for detecting displacement of a spot with respect to the guide groove by reflected light from the recording medium;
Polarity inverting means for inverting the polarity of the output signal of the track signal detecting means, control means for controlling the polarity inverting means based on the output signal of the information reproducing means, and the aforesaid output signal for the polarity inverting means. Tracking control means for controlling a spot so as to be located between the guide grooves or on the guide groove, and the track is arranged in a direction in which the information recorded on the optical recording medium is reproduced by the output of the information reproducing means. The polarity of the output signal of the signal detecting means is switched.

Secondly, in the first optical information recording / reproducing apparatus, the gain control means for changing the gain of the output signal of the track signal detecting means and the polarity switching operation of the output signal of the track signal detecting means are switched. Polarity direction recognition means for recognizing the direction in which the polarity of the output signal is switched according to the result, and, depending on whether the position where the spot is controlled is between the guide grooves or on the guide groove,
The gain control means is configured to switch the gain.

[0020]

In the present invention, attention is paid to the fact that the polarities of the tracking signals are opposite between the case where the tracking control is performed on the land and the case where the tracking control is performed on the groove. When the information of the control track is read and the address of the disk cannot be accurately detected, the polarity of the tracking signal is inverted and then the information of the control track is read (the invention of claim 1). Also,
Loops of tracking servo corresponding to each recording method so that stable tracking servo can be performed even for disks with different tracking detection gains when tracking control is performed on the land and when tracking control is performed on the groove. The gain is switched (the invention of claim 2).

[0021]

Embodiment 1 Next, an optical information recording / reproducing apparatus of the present invention will be described in detail with reference to the drawings. This embodiment mainly corresponds to the invention of claim 1, but is also related to the invention of claim 2.

FIG. 1 is a functional block diagram showing an embodiment of the main configuration of the optical information recording / reproducing apparatus of the present invention. In the figure, 1 is an optical disc, 2 is a tracking actuator, 3 is an optical pickup, 3a is its objective lens, 4 is a reproduction signal detection circuit, 5 is a data demodulation circuit, 6 is a track signal detection circuit, 7 is a polarity reversal circuit, 8
Is a controller, 9 is a gain variable circuit, 10 is a phase compensation filter, 11 is a drive circuit, and arrow A shows the moving direction of the objective lens 3a.

The characteristic of FIG. 1 is that a polarity reversing circuit 7 and a gain variable circuit 9 are newly added and that these circuits 7 and 9 are controlled by a controller 8. 9 is used in the invention of claim 2. Other configurations are basically the same as the conventional one. First, the same configuration and function as the conventional one will be described.

The optical pickup 3 focuses the laser light on the optical disc 1 in a spot shape to record / reproduce data. The reproduction signal detection circuit 4 detects a change in the amount of reflected light from the optical disc 1 and outputs it as a digital signal.

The output of the reproduction signal detection circuit 4 is given to the data demodulation circuit 5 to reproduce the data, and the controller 8
Sent to. The controller 8 recognizes the address and the like recorded in the track on the optical disc 1 based on the output signal from the data demodulation circuit 5.

Although not particularly shown, the controller 8 has a function of controlling the entire system including the rotation of the optical disc 1 and on / off control of focusing servo / tracking servo. The above is the operation common to the conventional device.

As described above, the optical information recording / reproducing apparatus of the present invention is characterized in that the polarity reversing circuit 7 is added, and the track signal detecting circuit 6 has the principle explained in FIG. The track signal is detected by. Output signal of the track signal detection circuit 6 (so-called track signal)
Is given to the drive circuit 11 via the polarity inversion circuit 7, the gain variable circuit 9, and the phase compensation filter 10.

The drive circuit 11 carries out tracking servo control by causing a current corresponding to the output signal of the phase compensation filter 10 to flow into the tracking actuator 2 and moving the objective lens 3a thereof in the track orthogonal direction. In this case, the controller 8 controls the polarity reversing circuit 7 and the variable gain circuit 9. Next, the operation of the optical information recording / reproducing apparatus of the present invention will be described with a flow.

FIG. 2 is a flow chart showing the main processing flow at the time of preparation for the recording / reproducing operation in the optical information recording / reproducing apparatus of the present invention. In the figure, # 1 to #
8 indicates a step.

When the optical disc 1 is loaded into the device, the flow of FIG. 2 starts. Note that step # 8
2 is related to the second embodiment, but has a lot in common with the first embodiment, and is shown in FIG. 2 for convenience of explanation.

First, in step # 1, the controller 8
However, the optical disc 1 is rotated to perform focusing control. In the next step # 2, tracking control is performed.
In step # 3, the address is detected by the output signal from the data demodulation circuit 5.

At step # 4, it is checked whether an address has been detected. If the address is detected correctly, it means that the current tracking polarity matches the recording method of the loaded disc.
Proceed to step 6 and, as it is, set the optical pickup 3 to the optical disk 1
In the radial direction (direction of arrow A in FIG. 1) to reproduce the control track.

Since information relating to the characteristics of the disc such as recording conditions and tracking polarities is recorded in advance on the control track, the controller 8 reads the information in the next step # 7 to read the characteristics of the disc. Recognize. Then, the process proceeds to step # 8 (described in the second embodiment). With the above processing, the preparation for the recording / reproducing operation is completed.

On the other hand, if no address is detected as a result of checking in step # 4, the process proceeds to step # 5. In step # 5, the controller 8 controls the polarity inversion circuit 7 to invert the polarity of the tracking signal.

Then, the process returns to the previous step # 2 and the same processing is performed. That is, the tracking control is performed again to reproduce the address. Steps # 1 to # above
By the processing of 8, the preparation for the recording / reproducing operation in the optical information recording / reproducing apparatus of the present invention is completed.

That is, regardless of whether the recording method of the loaded optical disk 1 is land recording or groove recording, the polarity of the tracking signal is inverted in the direction in which the address signal can be correctly detected, so that an optical sensor or the like is used. The recording method can be discriminated without the need to provide. As a result, the tracking control corresponding to the recording method of the loaded optical disk 1 can be performed, and the recording / reproducing operation of the disk of both recording methods can be performed.

[0037]

Second Embodiment Next, a second embodiment will be described. This second
In the embodiment of the present invention, due to the influence of the groove pitch (spacing), the shape of the fine groove, etc., even if the tracking detection gain is different between the case of tracking on the land and the case of tracking on the groove, It suppresses fluctuations in the loop gain of the tracking servo and enables stable servo control. Therefore, as described above, in the second embodiment, the gain variable circuit 9 is added to the above-mentioned FIG. 1, and step # 8 is added in the flow of FIG. 2 showing the control by the controller 8. This is different from the first embodiment described above.

FIG. 3 is a diagram for explaining the tracking gain control in the optical information recording / reproducing apparatus of the present invention, in which the amplitude of the track signal due to the grooves and lands on the disk corresponding to the land recording system and the groove recording system is shown. It is a figure explaining a change state. The horizontal axis of the figure represents time, the vertical axis represents the track signal amplitude corresponding to the groove and the land, b represents the gain of groove tracking, and c represents the gain of land tracking.

As shown in FIG. 3, even if the track signal has the same amplitude when tracking on the groove and when tracking on the land,
The tracking detection gain may differ. The reason is that the amplitude of the track signal is influenced by the pitch (interval) of the groove and the shape of the fine groove.

Here, the tracking detection gain is
It is the amplitude (volt) of the track signal with respect to the displacement amount (μm) of the light spot from the center of the land or groove. In FIG. 3, the groove tracking gain b is the gain when the light spot is at the center of the groove. , If the position of the light spot deviates from the center, it changes as shown by the arrow. In other words, in the waveform of FIG. 3, the detected gain corresponds to the amount of inclination of the amplitude of the track signal in the range indicated by the arrows on both sides of the position of the gain b.

This point is the gain c of land tracking.
Similarly, the gain c is a gain when the light spot is at the center of the land, and when the position of the light spot deviates from the center, the tracking detection gain changes as shown by arrows on both sides thereof. Then, this detection gain b,
When c changes like the waveform of FIG. 3, the loop gain of the tracking servo changes, so that the servo control becomes unstable.

Therefore, in the second embodiment, as shown in FIG.
As shown in FIG. 6, when the gain variable circuit 9 is added and the disc type (tracking polarity) is determined, the controller 8 changes the gain variable circuit 9 according to the disc recording method (land recording / groove recording). Control to switch the servo gain. In the waveform example of FIG. 3, a higher gain is set in the land recording method than in the groove recording method.

As a flow showing the operation of the optical information recording / reproducing apparatus shown in FIG. 1, step # 7 in FIG.
Then, the controller 8 reads the information on the controller track, recognizes the characteristics of the disc, and then proceeds to the next step # 8 to set the gain according to the polarity of the tracking signal. Note that the processing of step # 8, that is, the gain switching operation, may be performed at the time when the type of the disk (tracking polarity) is determined, and therefore need not always be performed after step # 7.
You may go immediately after 4.

As described above, by setting the gain according to the recording method of the disc, tracking is performed on the groove and on the land depending on the groove pitch (interval) and the shape of the fine groove. In some cases, even if the disc has different tracking detection gains, the servo control can be stably performed without changing the loop gain of the tracking servo.

[0045]

According to the optical information recording / reproducing apparatus of the present invention, the polarity reversing circuit 7 for reversing the polarity of the tracking signal is added, and the controller 8 controls the polarity reversing circuit 7 in the direction in which the address can be correctly detected. There is. Therefore, the disk loaded (mounted) in the drive device is
Regardless of whether it is the land recording method or the groove recording method, it is possible to determine the recording method without providing a special sensor, and it is possible to perform the recording / reproducing operation of both types of disks. it can.

In the optical information recording / reproducing apparatus of the second aspect, the loop gain of the tracking servo is switched between the case of tracking on the land and the case of tracking on the groove. Therefore, in addition to the effect of the optical information recording / reproducing apparatus of claim 1, tracking detection is performed depending on the pitch (interval) of the groove and the shape of the fine groove in the case of tracking on the land and the case of tracking on the groove. Even if the discs have different gains, it is possible to suppress the fluctuation of the loop gain of the tracking servo, and it is possible to perform stable servo control.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of the main configuration of an optical information recording / reproducing apparatus of the present invention.

FIG. 2 is a flowchart showing a main processing flow at the time of preparation for a recording / reproducing operation in the optical information recording / reproducing apparatus of the present invention.

FIG. 3 is a diagram illustrating tracking gain control in the optical information recording / reproducing apparatus of the present invention.

FIG. 4 shows a land recording method and a groove recording method.
It is a figure explaining the state of the address area and data area on a track.

FIG. 5 is a diagram showing a principle of a push-pull method used in an optical information recording / reproducing apparatus and an S-shaped curve of a tracking error amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 optical disk 2 tracking actuator 3 optical pickup 3a objective lens 4 reproduction signal detection circuit 5 data demodulation circuit 6 track signal detection circuit 7 polarity reversal circuit 8 controller 9 gain variable circuit 10 phase compensation filter 11 drive circuit

Claims (2)

[Claims] 1. An apparatus for recording / reproducing information by condensing a laser beam in a spot shape along an optical recording medium having a guide groove in advance, the reflected light from the recording medium Information reproducing means for reproducing information recorded on the recording medium, track signal detecting means for detecting displacement of the spot with respect to the guide groove by reflected light from the recording medium, and output signal of the track signal detecting means. Polarity inversion means for inverting polarity, control means for controlling the polarity inversion means based on the output signal of the information reproducing means, and the spot between the guide grooves or on the guide groove based on the output signal of the polarity inversion means Tracking control means for controlling so that the information recorded on the optical recording medium is reproduced by the output of the information reproducing means. The optical information recording / reproducing apparatus is characterized in that the polarity of the output signal of the track signal detecting means is switched in the opposite direction. 2. The optical information recording / reproducing apparatus according to claim 1, wherein the gain control means for changing the gain of the output signal of the track signal detecting means and the result of the polarity switching operation of the output signal of the track signal detecting means are used. Polarity recognition means for recognizing the direction in which the polarity of the output signal is switched, and the gain control according to whether the position where the spot is controlled is between the guide grooves or on the guide groove. An optical information recording / reproducing apparatus characterized in that the gain of the means is switched.