JPH06290465A - Optical disk recording medium - Google Patents

Abstract

PURPOSE:To provide an optical disk recording medium unnecessary for performing the jump and the forward/backward revolution of a disk at the time of recording/reproducing, in the optical disk recording medium recording and reproducing information in a groove and on a part between grooves. CONSTITUTION:The grooves 4 are formed or not formed along a spiral-shaped track 3 on every other revolution of the disk. Then, a radial position information generation part 5 is formed on the track e.g. by wobbling the groove, etc. The information is recorded on both of the inside of the groove 4 and the part 6 between grooves at the time of recording by rotating the disk based on the disk radial position information from the radial position information generation part and performing the CLV revolution control. Thus, the continuous recording and reproducing of the information is attained without performing the track jump.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read-only type, write-once type and rewritable type optical disc recording medium.

[0002]

2. Description of the Related Art In general, currently marketed CDs and LDs
In a read-only optical disc such as, a track width of about 0.5 μm along a spiral track with a track pitch of about 1.6 μm.
Pit of about micron is recorded as information by the change of the unevenness. In addition, write-once type that can be written once,
Similarly, in the rewritable optical disk, spiral guide grooves are formed at a track pitch of about 1.6 microns, and information is recorded in or between the guide grooves to form tracks.

By the way, recently, there has been an increasing demand for miniaturization of recording media and high image quality, and there is a demand for improvement of recording density.
In order to improve the recording density, researches and developments have been made to shorten the laser wavelength used for recording / reproducing and to increase the NA (aperture) of the lens. However, the development of a short wavelength blue laser is difficult at this stage, its appearance is expected in the 21st century, and the precision of the disk used with a high NA lens becomes strict.

Another method for increasing the recording density is to increase the track density, but when the track density is increased, the following two problems occur. Crosstalk between adjacent tracks cannot be tracked

The crosstalk is a phenomenon in which, for example, the information of a track adjacent to the track to be reproduced is mixed with the information of the reproduction track. As a measure against this crosstalk, the multi-beam reproduction is performed and the adjacent track is reproduced. Method (Japanese Patent Laid-Open No. 3-232118), the groove depth is set to about λ · ⅕ so that even if information is recorded on both the convex portion and the concave portion, the crosstalk on the adjacent track is prevented. Although a method capable of reducing the amount (the Society of Applied Physics (Autumn) 18a-T-3 in 1992) and the like have been proposed, it is not preferable to perform these methods because the apparatus becomes complicated. Regarding tracking, if the track density is increased, the tracking guide groove cannot be detected from the resolution of the recording / reproducing optical pickup, or even if it can be detected, the signal is small and the tracking stability deteriorates.

Therefore, the following means have been proposed as a method for substantially increasing the track density. For example, a method for recording information in both the convex portion and the concave portion of a tracking guide groove as proposed in Japanese Patent Laid-Open No. 59-139147, and a tracking guide as proposed in Japanese Patent Application No. 3-165114. There has been proposed a method of recording information as a change of unevenness on both the convex portion and the concave portion of the groove, and a method of changing the adjacent groove depths as proposed in Japanese Patent Laid-Open No. 104021/1993. .

[0007]

By the way, the guide groove of the recording medium disclosed in the above publication is continuous (although it may be discontinuous for recording a pre-formatted signal or the like, it does not appear every other rotation. Since it is not assumed to jump to the adjacent groove or the land portion between the grooves, it is regarded as continuous.) When recording and reproducing long information such as audio signals and video signals, for example, record in the groove recesses. If you start it, you need to continue recording in the recess, and if there is no space to record in the recess, reverse the rotation of the disk or move the optical head to the initial position and record in the protrusion. There is a need to. Alternatively, a method of jumping a track and recording / reproducing each time the disk rotates once is also conceivable.

The state at this time will be described with reference to FIG. 6. In FIG. 6, reference numeral 1 denotes a spiral guide groove 1 formed in the optical disk recording medium, which is formed in both the groove (concave portion) and the groove (convex portion). The case of recording will be described. For example, when recording is started from point A, recording is performed up to point C on the innermost circumference, and when returning to the first point D between the grooves and recording is started (case 1), point C is determined on the innermost circumference. When recording and reversing the rotation of the disk and recording between the grooves (case 2), after recording up to the point B along the groove, jump to the first point D between the grooves and move to the point E along the groove. There is a case where the recording is further performed after jumping to the point B of the groove after the recording up to this point, and then the recording is repeated by repeating this jump every other round of the disk (case 3). However, in cases 1 and 2,
It takes time when the recording / reproducing position is switched from the groove (recess) to the groove (convex) or vice versa, which causes a problem that the continuity of reproduction or recording is interrupted.

In case 3, it takes time to stabilize the jump and tracking after the jump, which is not preferable for recording continuous information, and CLV (Constant Linea) so that the linear velocity is always constant.
r Velocity) In the case of performing control recording or in the case of audio, it is necessary not to record information at the jump position, which is also not preferable in this respect. Here, CLV control means that a synchronization signal is embedded in a disc by pits (wrinkles) or wobbles (meandering guide grooves), and when the drive is performed, the rotation reference signal of the drive and the synchronization signal of the disc are synchronized. It is a control method in which the linear velocity is kept constant by controlling the rotation.

It is also conceivable to use a buffer or the like for compensating the information until the tracking becomes stable, but this is not preferable in terms of price and stable operation. The present invention has been made in view of the above problems and was devised to effectively solve the problems, and an object thereof is an optical disk recording medium for recording and reproducing information both in and between grooves. It is an object of the present invention to provide an optical disk recording medium which does not require a jump or a forward / reverse rotation of a disk during reproduction / recording in a recording / reproducing method.

[0011]

In order to solve the above-mentioned problems, the present invention provides an optical disk recording medium having a spiral track on which information is recorded or information is recorded, wherein the track partially has a groove. In addition, the groove is formed approximately every other rotation of the optical disc recording medium, and the track constitutes a radial position information generating portion of the optical disc recording medium.

[0012]

Operation: Information is recorded on the optical disk recording medium described above,
Further, when reproducing information from this, the radial position information generating portion of the recording medium, for example, wobbling information obtained from wobbling formed in the groove or the disc radial position information obtained by the change of the unevenness formed in the middle of the track Based on the above, the rotation is controlled to record information in the groove or in the groove portion along the spiral track, or reproduce the recorded information.

[0013]

An embodiment of an optical disk recording medium according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a plan view of an optical disk recording medium according to the present invention, FIG. 2 is a main block diagram of an apparatus for recording / reproducing the recording medium shown in FIG. 1, and FIG. 3 is a rotation control reference in the block diagram shown in FIG. It is a block diagram which shows a signal generation circuit.

As shown in the figure, the disc-shaped optical disc recording medium 2 has a spiral track 3 on which information is recorded or on which information is recorded, and the track density is tracked as described later. The track density is substantially double that of the conventional method in which information is not recorded on both the convex portion and the concave portion of the guide groove. The track 3 partially has a groove 4 having a width smaller than the track pitch, for example, about 1/2. For example, the groove 4 is formed every other rotation of the recording medium. Specifically, the groove 4 is formed, for example, about one round from a point A1 which is the starting point of the outermost track to a point B1 which is located inside by a track pitch.
About one round from the point B1 to the point A2 located further inside by a track pitch is not formed. Further, similarly, the groove 4 is formed from the point A2 to the point B2 located further inside by the track pitch, and the groove 4 is not formed from the point B2 to the point A3 located further inside by the track pitch. Thus, the intermittent formation of the groove 4 is repeated until the point C on the innermost track of the track. When the formation of the groove 4 is started from the innermost track, the groove is intermittently formed up to the outermost circumference as described above.

In this case, when recording or reproducing information, for example, the information is recorded in the groove 4 from the point A1 to the point B1, and the tracking polarity is reversed at this point to the groove from the point B1 to the point A2. Information is recorded in the space 6. Then, the tracking polarity is returned again, the information is recorded in the groove 4 from the point A2 to the point B2, and the tracking polarity is further reversed from the point B2 to the point A3 to record the information in the inter-groove portion. Similarly, recording or reproduction is performed while reversing or returning the tracking polarity. By doing so, continuous recording / reproduction of information becomes possible, and it is not necessary to perform track jump to maintain continuity. Reversing the tracking polarity in this manner has no technical problem because it has been widely adopted in the related art. For example, an uneven portion 7 having a constant frequency is formed immediately before the groove 4 disappears and immediately before the groove 4 starts. All you have to do is increase tracking stability.

The method for forming such a groove is, for example, similar to the conventional method for forming a guide groove, in which a glass disk coated with a photoresist is irradiated with laser light by a laser cutting machine, and the development, plating and pressing steps are performed. Can be formed. In this case, laser light irradiation is applied to the disk 1
Use an optical modulator etc. to turn on and off every cycle. Further, in order to record or reproduce information on this disc by CLV control, it is necessary to control the rotation of the disc so that the linear velocity is constant, and in the case of reproduction, the rotation is detected from the recorded information. The rotation of the disc can be controlled by performing the above procedure, but in the case of recording, it is necessary to previously input a signal for controlling the rotation to the disc itself.

Therefore, the track 3 is provided with a radial position information generator 5 for generating radial position information of the disc. Specifically, the radial position information generating unit 5
In this embodiment, the groove 4 is formed by wobbling (meandering) with the carrier frequency modulated by the time information. Since the wobbling amplitude is very small, it is not shown in the illustrated example. This wobbling technique has been conventionally used in, for example, a write-once CD (CD-R) or a rewritable mini disc (MD), and the groove is slightly meandered to synchronize absolute time (or address) and CLV. It is designed to embed a signal. Specifically, digital data such as absolute time (or address) is FM (frequency modulated), and the groove is slightly meandered by the signal. When recording, the FM signal corresponding to the meandering of the groove is included in the error signal of the tracking servo.
Since the signal is included, this is extracted by a bandpass filter or the like to CL the FM carrier (FM center frequency).
It is used as a V sync signal to demodulate the FM modulation component to read the absolute time (or address). CD-
For R and MD, for example, FM of 22.05 KHz ± 1 KHz
Is selected as a frequency that does not affect the tracking servo and data. In this case, in this embodiment, 1
Since the groove is formed every rotation, the wobbling signal cannot be detected in the track in which the groove is not formed. However, when the track density is increased as in the present embodiment, the difference in the number of revolutions between the adjacent tracks is about ± 0.005%, which is very small.
The wobble signal of one rotation before may be held and stored, and the rotation of the disk may be controlled using this.

Here, FIG. 2 and FIG. 3 show the main parts of the recording / reproducing apparatus for the optical disk recording medium 2 formed as described above.
This device has a bandpass filter BPF for extracting the FM wobbling signal S2 included in the tracking error signal S1 from the tracking servo (not shown), and this filter BPF has disc position information. The detection unit 7 is connected and outputs the position information S3 and the detection OK / NG signal S4 indicating whether or not the wobbling signal can be detected from the FM wobbling signal S2. The rotation control reference signal generation circuit 13 connected to the detection unit 7 is configured as shown in FIG. 3, and when the detection OK / NG signal S4 indicates that NG, that is, a wobbling signal cannot be detected, the immediately preceding signal is output. The data hold circuit 8 holds and stores the position information S3 for one rotation, and the variable frequency divider 10 for dividing the reference signal from the crystal oscillator 9 based on the output of the hold circuit 8, for example. The frequency divider 10 outputs a spindle servo reference signal S5. The output of the frequency divider 10 is connected to a spindle servo circuit 11 that controls the rotation of the disk,
The rotation of the disk drive motor 12 is controlled with reference to the output signal from the encoder 16.

Next, a recording / reproducing method for the above-mentioned optical disk recording medium will be described. When recording or reproducing information, as described above, from point A1 to point B shown in FIG.
Information is recorded in the groove 4 up to 1, and the tracking polarity is reversed here, and information is recorded in the groove portion 6 from the point B1 to the point A2.
From point A2 to point B2, the tracking polarity is returned again and recording is performed in the groove 4, and from point B2 to point A3, the tracking polarity is reversed and recording is performed in the inter-groove portion 6. In the same manner, recording or reproduction is performed by reversing or returning the tracking polarity in the same manner. In this case, the tracking polarity is changed by detecting the concavo-convex portion 7 having a constant frequency provided immediately before the groove 4 disappears and immediately before the groove 4 starts.

The CLV control of the disc is a signal embedded in the groove 4 by passing the tracking error signal S1 output from the tracking servo through the bandpass filter BPF, as shown in the blocks shown in FIGS. Is taken out as the FM wobbling signal S2,
Based on this signal, the disc position information detection unit 7 outputs the position information S3 indicating the radial position of the disc and the detection OK / NG signal S4. Rotation control reference signal generation circuit 13
Outputs a spindle servo reference signal S5 for controlling the rotation of the disk based on the above two signals S3 and S4, but when recording in the inter-groove portion 6, the wobbling signal S2
Therefore, the wobbling signal of one rotation before is held in the data hold circuit 8, and the rotation of the disk is controlled based on this. As described above, according to the present embodiment, it is possible to continuously record and reproduce information without the need for a track jump. In addition, recording or reproducing can be substantially doubled at a low cost without complicating the device.

In the above embodiment, the radial position information generating section 5 for generating the radial position information of the disk is formed by woblinking the groove 4, but the invention is not limited to this and is shown in FIG. 4, for example. As described above, the unwobbled grooves 14 are cut at short intervals at regular intervals, and disc radial position information such as a track number is embedded in the cut intervals by forming an uneven portion. It may be formed. In this case, the radial position information generators 5 are formed in the inter-groove portions 6 at the same constant intervals as when the grooves 14 were cut and at the same short intervals. FIG. 4 shows a schematic diagram in which a part of the disk recording medium at this time is extracted, and positional information at this time is a concave and convex signal of 2 bytes, for example, and is inserted at an interval of 5 KHz.

The rotation control of the disc in this case is performed by the disc position information extraction circuit 15 based on the high frequency reproduction signal S6.
Outputs the disk position information S7, and based on this, the frequency divider 10 outputs the spindle servo reference signal S as described above.
5 is output and the rotation of the disk is controlled. In this case, the radial position information generating section 5 may not be formed in the inter-groove portion 6, and at this time, the radial position information formed in the groove 14 for one rotation is used as the disc position as described in FIG. By holding and storing the information in the information extraction circuit 15, the CLV rotation control can be performed on the inter-groove portion 6 as well.

[0023]

As described above, according to the optical disk recording medium of the present invention, the following excellent operational effects can be exhibited. Since a groove is formed every other rotation and information is recorded in both the groove and the inter-groove portion, continuous recording / reproduction of information can be performed without jumping the track, which is inexpensive and stable. As a result, it is possible to perform recording with substantially double the track density.

[Brief description of drawings]

FIG. 1 is a plan view of an optical disc recording medium according to the present invention.

2 is a main block diagram of an apparatus for performing recording / reproduction of the recording medium shown in FIG.

3 is a block diagram showing a rotation control reference signal generating circuit in the block diagram shown in FIG. 2;

FIG. 4 is a schematic view showing a part of a modified example of the optical disc recording medium according to the present invention.

5 is a block diagram for explaining a recording / reproducing method of the recording medium shown in FIG.

FIG. 6 is a plan view showing a conventional optical disc recording medium.

[Explanation of symbols]

2 ... Optical disk recording medium, 3 ... Track, 4, 14 ...
Grooves, 5 ... Radial position information generating section, 6 ... Inter-groove section, 7 ... Disk position information detecting section, 8 ... Data hold circuit, 9 ... Crystal oscillator, 10 ... Divider, 15 ... Disk position information extracting circuit, S1 ... tracking error signal, S2 ... FM wobbling signal, S3 ... position information, S4 ... detection OK / NG signal, S5 ... spindle servo reference signal.

Claims (1)

[Claims] 1. An optical disc recording medium having a spiral track on which information is recorded or information is recorded, wherein the track partially has a groove and the groove is formed approximately every one rotation of the optical disk recording medium. The optical disc recording medium, wherein the track has a radial position information generating portion of the optical disc recording medium.