JPH07272420A - Disc recording/reproducing system - Google Patents

Abstract

PURPOSE:To achieve an effective utilization of a memory capacity of a disc by reducing the memory capacity of a buffer memory required. CONSTITUTION:An information signal is recorded up to a point b1 just before one round of a disc from a point a1 and when recording reaches this information recording end point b1, a jumping is made from one track to a group on one inner circumference side. At this point, the point b1 is set so that a point c3 located at a position before a light beam reaches a point c1 makes a track jumping end point and the information signal is recorded from the point c1. Then, the information signal is recorded up to a point d1 just before the further one round of the disc and when the recording reaches the end point d1 of recording the information, a jumping is made from the track to a land part on one inner circumference side. At this point, the point d1 is set so that the point b3 located at a position before reaching the information recording end point bl makes a track jumping end point. The information recording end point b1 is defined as the information recording start point of the next information signal.

Description

Detailed Description of the Invention

[0001]

[0001]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc recording / reproducing system of an optical disc recording / reproducing apparatus for irradiating a convergent beam on an optical disc recording medium having grooves formed at a predetermined pitch to record and / or reproduce information. It is a thing.

[0003]

[0002]

[0004]

2. Description of the Related Art An optical disc is one of recording media capable of high-density information recording. In order to perform stable recording / reproducing of information, this optical disc has beam guide grooves (grooves) formed in a concentric circle shape or a spiral shape in advance, and its convex portion (land portion) or concave portion (groove) between them is formed. ) Is recorded and played back. In early optical discs, in order to prevent crosstalk during reproduction, information was recorded only in either the groove or the land portion, but in recent years information is recorded in both the groove and the land portion. However, a method of recording / reproducing twice as much information as in the case of using only one of them has been considered. As a method of recording information in both the groove and the land, for example, Japanese Patent Publication No.
No. 27610 discloses a method of recording / reproducing information on both the groove and the land portion by switching the polarity of the tracking control system.

[0005]

[0003]

[0006]

In this way, when recording and reproducing a continuous information signal (linear program) such as a video signal in both the land portion and the groove, it is possible to prevent the information signal from being interrupted by a track jump or the like. Therefore, the information signal is temporarily stored in a buffer or the like before recording / reproducing.

The following two methods are conceivable as the disk recording / reproducing method for recording / reproducing the information signal on / from the optical disk recording medium. The optical disk recording medium described here is assumed to have spiral tracks.

[0008]

The first method will be described with reference to FIG. now,
In an optical disc recording medium as shown in FIG. 4, consider recording or reproducing an information signal from a point e on the innermost circumference of the land portion.

First, an information signal is recorded or reproduced from this point e along the spiral land portion track, and recording or reproduction is performed up to the outermost point f of the land portion. Next, the track jumps back to the innermost groove point g, the polarity of the tracking control system is switched, and then an information signal is recorded or reproduced from the innermost point g of the groove toward the outer circumference of the groove track. To go.

[0010]

At this time, in order to record or reproduce the information signal which is the linear program without interruption, the information for the time during the movement from the outermost point f of the land portion to the innermost point g of the groove is buffered. It needs to be stored in memory and connected well. Also, the disk is CLV
When rotating with (constant linear velocity) control, the number of rotations is significantly different between recording and reproducing on the outermost circumference and recording and reproducing on the innermost circumference, so the spindle motor stays within the specified rotation speed. It is necessary to store the information for the time until it is controlled in the buffer memory.

Therefore, when information is recorded and reproduced by this method, a buffer memory having a large storage capacity is required.

[0012]

As a second method, a method as shown in FIG. 5 can be considered. In other words, the polarity of the tracking control system is switched for each round of the disc, and the land portion → the groove,
In this method, the land and groove are alternately recorded or reproduced while jumping from groove to land. In the figure, an information signal is recorded or reproduced from a point h at the innermost circumference of the land portion to a point i after one round, and a track jump is performed from this point i to a point j of the groove on the inner circumference side, and a tracking control system The information signal is recorded or reproduced in the same manner from the point j to the point k after one round by switching the polarity of, and the track jump from this point k to the point 1 of the land portion on the inner circumference side is performed. The polarity is switched to continue recording or reproducing the information signal.

[0013]

In this case, since the time for recording or reproducing the information signal is only the time required for jumping to the adjacent track even in the case of CLV control, in order to record and reproduce the information signal which is a linear program without interruption. The required storage capacity of the buffer memory is the first as shown in FIG.
It is much less than the method.

However, according to this method, recording or reproduction cannot be performed during the time between track jumps, for example, point i → point j and point k → point l. The information signal is not recorded in the area between 1 and the like, and the storage capacity of the disk is reduced accordingly.

[0015]

Therefore, the present invention solves the above problems and reduces the storage capacity of the buffer memory required when recording or reproducing a linear program such as a video signal in both the land portion and the groove of the disc. It is an object of the present invention to provide a disc recording / reproducing system that effectively utilizes the storage capacity of the disc.

[0016]

[0009]

[0017]

As a means for achieving the above object, a disk recording / reproducing system for irradiating a convergent beam to a disk-shaped recording medium having grooves formed at a predetermined pitch to record / reproduce information. That is, when performing recording / reproducing of information for the groove and the land portion between the grooves approximately every one turn, a start point of a track jump for jumping from one of the groove and the land portion to the other is set. Recording and reproducing are performed at a position after the information recording end point of the groove or the land portion and at a position before the information recording end point of the land portion or the groove destination of the jump destination. The present invention aims to provide a disc recording / reproducing system characterized by the following.

[0018]

[0010]

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the disk recording / reproducing system of the present invention will be described with reference to FIG.

FIG. 1 is a diagram showing an embodiment of a disk recording / reproducing system of the present invention. This optical disk recording medium has spiral tracks, and the information recording start point of the innermost circumference of the recordable or reproducible land part is a1, and the innermost point of the recordable or reproducible groove is the innermost circumference point. It is assumed that the information recording start point is c1 and the information signal is recorded or reproduced from the information recording start point a1 at the innermost circumference of the land portion. Further, in the following description, the case of recording the information signal is described, but the same applies to the case of reproducing the information signal.

[0021]

When the information signal is being recorded from the point a1,
The light beam for recording / reproducing information is designed so that tracking control is applied to the land portion and moves along the land portion. Then, the information signal is recorded up to a point b1 slightly before the light beam makes one round of the disk, and when it reaches the point b1 (information recording end point) or a point b2 slightly ahead of the point, one inner circumferential side Track jump to the groove. At this time, the polarity of the tracking control system is switched during the track jump. Also, at the point b1 or the point b2 which is the start point of the track jump, the light beam is at the point c1.
The point c3 or the point c4 at the position before reaching the point c is set to be the end point of the track jump, and the recording operation of the information signal can be normally performed from the point c1.

[0022]

Since the polarity of the tracking control system is switched during the track jump, the point c1
Then, the light beam is subjected to tracking control on the groove, and recording is performed along the track of the groove. Then, an information signal is recorded up to a point d1 slightly before this light beam makes another round of the disk, and when it reaches the point d1 (information recording end point) or a point d2 a little further ahead, one inner circumference side. Jump to the land area of. At this time, the polarity of the tracking control system is switched during the track jump. Also, the point d1 which is the start point of the track jump
Alternatively, the point d2 is set so that the point b3 or the point b4 at the position before the light beam reaches the point b1 which is the information recording end point of the information signal previously recorded on the land portion becomes the end point of the track jump. Point b1 that is the end point for setting and recording information
Recording is performed by using as the information recording start point of the next information signal.

[0023]

Thereafter, in the same manner, one inner circle is made at a point slightly before one round so that the position before the information recording end point of the previously recorded information signal reaches the track jump end point. Continue recording to the outermost circumference of the disc while jumping to the land or groove on the side.

[0024]

As described above, the information recording end point is set at a position slightly before the light beam makes one round around the disc, and the track jump start point when the track jump is started at a position after the end point including this end point. Is set so that the track jump end point comes before the information recording end point of the previously recorded information signal, so that the next information signal can be recorded continuously from this information recording end point. Therefore, there is no unrecorded area between the information recording end point of the previous information signal and the information recording start point of the next information signal,
It is possible to efficiently use the recording area of the disc and perform recording at high density.

[0025]

Although the point c1 is not strictly the information recording end point, information cannot be recorded in the area before the point c1. Therefore, the area is regarded as an unrecordable (recorded) area. , Point c1 can be regarded as equivalent to the information recording end point.

Information recording start points a1, b1, c1,
d1 (information recording end points b1 and d1) and track jump start points b1, b2, d1 and d2 are the information recording end points b1 and c1 of the information signals previously recorded by the track jump end points b3, b4, c3 and c4. It is possible to make the track jump accurately by deciding in advance the time taken for the track jump so that it comes to a position earlier than that, and for example, by engraving the address and other marks on the disc. .

[0027]

Since the time that is interrupted when recording or reproducing by this method is almost the same as the time required for the track jump, the capacity of the buffer memory required to absorb the interruption of the linear program is one track. It would be good if we could store enough information.
It should be noted that, in order to absorb the discontinuity of information at the time of track jump, the disc is rotated slightly faster than in the case of recording in real time.

[0028]

Next, FIG. 2 shows an example of the polarity switching timing of the tracking control system at the time of track jump.
A description will be given using (A) to (D). In the figure (A)
Is a track cross section, (B) is a tracking error signal when a track jump is made from a land portion to a groove (or from a groove portion to a land portion), and (C) is a tracking error signal shown in FIG. The subsequent differential signal, (D), shows jump pulses for causing a track jump.

[0029]

In an optical disk recording medium in which information is recorded only in the land portion or only in the groove, track jump is performed from land portion to land portion (or groove to groove), but in the present invention, land portion and groove are alternated. Since recording or reproduction is performed, track jumps from the land portion to the groove and from the groove portion to the land portion are required. Considering the case where the track jumps from the land portion to the groove as shown in FIG. 7A, the tracking error signal is as shown in FIG. When the tracking error signal is differentiated, a zero cross point t0 is generated at the edge portion between the land portion and the groove, as shown in FIG. Therefore, when the polarity of the tracking control system is switched in the middle of the track jump, a jump pulse as shown in FIG. 7D is used as the zero cross point t0 as the switching timing of the acceleration pulse and the deceleration pulse during the track jump. You can use it.

Even when the track jump is performed from the groove to the land portion, the signal waveforms in FIGS. 6B to 6D are exactly the same.

[0031]

An embodiment of an optical disk recording / reproducing apparatus for realizing such a disk recording / reproducing system is shown in FIG.
And will be described below. In the present invention,
Since the polarity of the tracking error signal applied to the tracking means is reversed depending on whether the beam spot scans the groove or the land portion, the moving direction of the beam spot depending on whether the tracking error signal is positive or negative. , The groove and the land portion are coincident with each other during scanning.

[0032]

Further, in the present embodiment, when the information processing control unit 10 switches the beam scanning from the groove to the land portion, a track jump pulse is applied to the tracking means so that the beam spot is moved between the groove and the land portion. At the same time as this track jump, the polarity of the tracking error signal applied to the tracking means is controlled to be inverted. Although various methods such as a conventionally known push-pull method and heterodyne method can be used as the method of creating the tracking error signal, the push-pull method is used in this embodiment. For the displacement of the beam spot in the tracking direction, an existing objective lens drive actuator used in a compact disc player or the like is used. That is, this is performed by displacing the objective lens for beam focusing in the tracking direction. Since the push-pull method and the objective lens drive actuator are the same as those of the conventional ones, detailed description thereof will be omitted.

[0033]

In FIG. 3, the servo photodetector 1 receives two beams reflected from the groove or land to be scanned. Then, when the beam spot is accurately positioned in the groove or land to be scanned, the magnitudes of the signals output from the respective detectors are equal, but the beam spot deviates from the groove or land to be scanned in the tracking direction. Then, the signal output from one of the detectors becomes larger than that of the other, depending on the direction of deviation.

[0034]

This output signal is supplied to the differential amplifier 3 via the polarity switcher 2 and is output as a tracking error signal indicating the difference between the input signals. The tracking error signal is phase-compensated by the phase compensator 4 and then supplied to the switcher 5. Here, the switch 5 is connected to the phase compensator 4 side while normal tracking control is being performed. Therefore, the tracking error signal is normally applied to the tracking drive unit 6 via the switch 5, and the tracking drive unit 6 drives the tracking actuator 7 for driving the objective lens in response to the tracking error signal. As a result, tracking adjustment of the beam spot is performed, and recording / reproduction of information is performed.

[0035]

When the address detection circuit 9 detects the address signal of the track jump from the signals supplied from the reproduction signal photodetector 8, the detection signal is output to the information processing controller 10. The information processing control unit 10 supplies a signal to the jump pulse generation circuit 13 to generate an acceleration pulse having a positive level (FIG. 2D) and switches the switch 5 to the jump pulse generation circuit 13 side. , And supplies this acceleration pulse to the tracking drive unit 6. When the acceleration pulse is supplied, the tracking drive unit 6 drives the tracking actuator 7 to move the objective lens in the radial direction of the disk (for example, the direction from the outer circumference of the disk toward the inner circumference) to move the beam spot from the land section to the groove section. (Or move from groove to land).

[0036]

With the movement of the objective lens, the difference between the signals output from the servo photodetector 1 increases, and the value of the tracking error signal (FIG. 2B) output from the differential amplifier 3 increases. growing. Further, the tracking error signal is supplied to the differentiating circuit 11, and once it becomes large, as shown in FIG. 2C, takes a value that gradually decreases. And this differentiating circuit 1
The output of 1 is supplied to the zero-cross point detection circuit 12 and outputs a detection signal when the zero-cross point t0 is reached (when the beam spot comes to the edge portion between the land portion and the groove portion).

[0037]

The detection signal output from the zero-cross point detection circuit 12 is supplied to the information processing control section 10 and the jump pulse generation circuit 13. Then, when the detection signal is supplied, the information processing control unit 10 switches the polarity switch 2 to invert the polarity of the signal output from the servo photodetector 1 to the differential amplifier 3. When the detection signal is supplied, the jump pulse generation circuit 13 sends to the tracking drive section 6 a negative level deceleration pulse (FIG. 2D) having a predetermined time width based on the inertial movement of the objective lens. Then, the inertial movement of the objective lens by the tracking actuator 7 is stopped, and the tracking is adjusted to the groove or land.

[0038]

When the tracking is completed, the information processing control unit 10 switches the switching unit 5 to the phase compensation unit 4 side again, and the tracking is followed until the address indicating the next track jump start position is detected. At this time, since the polarity of the output signal of the servo photodetector 1 supplied to the differential amplifier 3 is reversed by the polarity switcher 2 during the track jump, the land portion changes to the groove portion (or the groove portion to the land portion). Tracking tracking can be performed even if it changes.

[0039]

The position of the address indicating the track jump start position of the disc is before the information recording end point when the switch 5 is switched again to the phase compensator 4 side after the tracking alignment after the track jump ends. It is a position where the beam spot comes to the position of.

Further, in the above embodiment, since the recording of the information signal is started from the inner circumference side, the track jump is made to one groove or land portion on the inner circumference side, but the recording of the information signal is carried out on the outer circumference side. In the case of starting from, a track jump is made to one groove or land on the outer peripheral side.

[0041]

[0028]

[0042]

According to the disk recording / reproducing system of the present invention, when the recording / reproducing of the information is alternately performed on the groove and the land portion for every one turn, the track jump of one of the groove and the land portion to the other is performed. The start point is set to a position after the information recording end point of the groove (land portion), and the end point of the track jump is set to a position before the information recording end point of the jump destination land portion (groove) to perform recording and reproduction. Therefore, the land portion and the groove can be switched in a short time, the buffer memory capacity necessary for recording (reproducing) a linear program such as a video signal can be reduced, and the CLV control can be performed. In this case, there is almost no disc rotation fluctuation when switching between the land portion and the groove.

Then, since there is no unrecordable area on the track of the disc, and the entire surface can be recorded without waste, there is an effect that the storage capacity of the disc is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an optical disc to which an embodiment of a disc recording / reproducing system of the present invention is applied.

2A to 2D are graphs showing a timing chart at the time of track jump of the disk recording / reproducing system of the present invention.

FIG. 3 is a block diagram showing an embodiment of an optical disc recording / reproducing apparatus using the disc recording / reproducing system of the present invention.

FIG. 4 is a first disc recording / reproducing system that can be easily considered.
It is a block diagram which shows the system of.

FIG. 5 is a second disc recording / reproducing system that can be easily considered.
It is a block diagram which shows the system of.

[Explanation of symbols]

 1 Photodetector for Servo 2 Polarity Switch 3 Differential Amplifier 4 Phase Compensator 5 Switch 6 Tracking Drive 7 Tracking Actuator 8 Photodetector for Playback Signal 9 Address Detection Circuit 10 Information Processing Controller 11 Differentiation Circuit 12 Zero Cross Point Detection Circuit 13 Jump Pulse generation circuit a1, c1 information recording start point b1, d1 information recording end point b3, b4, c3, c4 track jump end point

Claims (1)

[Claims] 1. A disc recording / reproducing system for recording / reproducing information by irradiating a convergent beam on a disc-shaped recording medium having grooves formed at a predetermined pitch, wherein a land portion between the grooves is formed. On the other hand, when information is recorded / reproduced alternately for every one turn, the start point of the track jump for jumping from one of the groove and the land portion to the other is set after the information recording end point of the groove or the land portion. A disc recording / reproducing system characterized in that the recording / reproducing is performed while the track jump end point is set to a position before the information recording end point of the land portion or the groove of the jump destination.