JPH0719432B2 - Optical disc recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical disc recording / reproducing apparatus for recording or reproducing information on a so-called follow-up type or rewritable type optical disc, and more specifically to a linear velocity. The present invention relates to the rotation control of an optical disk that is constant.

[Conventional technology]

Conventionally, so-called compact discs (hereinafter referred to as CDs) in which music information and the like are recorded as digital signals by mechanical pits are widely used. This CD is played back by a playback-only optical disk playback device.

Usually, a plurality of pieces of information are continuously recorded on the above-mentioned CD, and at the time of reproduction, the absolute address pre-recorded on the disc and the TOC (Tab (Tab)
The continuous reproduction of the desired information, the selective reproduction, etc. are performed by collating with the recording start absolute address value of each information recorded in the le Of Contents area.

On the other hand, when recording and using music information on a rewritable disc such as a magneto-optical disc which has been developed in recent years or a write-once optical disc that can record only once, It is desirable to provide a compatible optical disc recording / reproducing apparatus by making the reproducing system common between them. In that case, as a method for controlling the rotation of the optical disc during recording or reproduction, so-called constant linear velocity control (hereinafter, referred to as CLV (Constant Linear Velocity) control) implemented by a CD can be adopted.

By the way, when controlling the rotation of an optical disc with CLV,
For example, it is conceivable to control the rotation speed of the motor according to the rotation speed of the motor detected by a rotary encoder or the like and the radial position of the optical head rendered by the position detection sensor. Since a detection error of the position detection sensor or the like occurs, it is impossible to expect sufficiently accurate rotation control.

Therefore, it is conceivable to perform CLV control based on information previously recorded on the optical disc, such as the absolute address described above. Conventionally, as a method of recording an absolute address, after biphase mark conversion of the absolute address, the guide groove of the optical disk is set to the inner side or the outer side in the radial direction depending on whether each bit is “1” or “0”. It has been proposed that the guide groove is biased or the width of the guide groove is changed (see Japanese Patent Laid-Open No. 64-39632). In that case, if the frequency band of the absolute address and the frequency band of the recorded information are made different, it is possible to reproduce the both separately.

[Problems to be Solved by the Invention]

However, as described above, even if the information is recorded while rotating the optical disc by using the information such as the absolute address previously recorded on the optical disc as the pre-recording signal regarding the position, the error in the CLV control at the time of recording is actually Etc.
Information may be recorded with a slight deviation from the CLV condition. In this case, if the information to be recorded is music information, there will be slight variations in the playing speed during reproduction, and the sound quality will be impaired. Therefore, when reproducing information,
It is preferable to perform CLV control based on the reproduced information.

However, during reproduction, for example, when a recorded area approaches an unrecorded area on the optical disc, there is a problem that rotation control based on reproduction information becomes impossible. Also, once
Even after the rotation control by the reproduction information becomes impossible, even if the reproduction signal quality is recovered, it takes a considerable time to perform the correct rotation control.

[Means for Solving the Problems]

In order to solve the above problems, an optical disk recording / reproducing apparatus according to the present invention performs recording or reproduction on an optical disk on which rotation control information for performing rotation control at a constant linear velocity is recorded as prerecorded information over the entire surface. In the optical disk recording / reproducing apparatus, an address management unit that records a recording start absolute address value obtained from the pre-record information at the start of the recording operation and stores a recording end absolute address value obtained from the pre-record information at the end of the recording operation. ,
At the time of recording, rotation control is performed at a constant linear velocity using the above-mentioned pre-recorded information, and at the same time, the recording start and recording end absolute address values stored in the address management section are recorded in a predetermined area of the optical disc, and a reproduction signal is reproduced at the time of reproduction. On the other hand, while controlling the rotation at a constant linear velocity based on the above, the above-mentioned recording start and recording end absolute address values are read from the predetermined area of the optical disc to the address management unit and compared with the absolute address value of the area being reproduced. Accordingly, it is determined whether the area is a recorded area or an unrecorded area, and when it is determined that the area is an unrecorded area, the rotation control with a constant linear velocity based on the reproduction signal is switched to the rotation control with a constant linear velocity based on the prerecorded information. And a control means are provided.

[Work]

According to the above configuration, when recording in the unrecorded area of the optical disc, rotation control of constant linear velocity (CLV) is performed based on the prerecorded information, and during playback, CLV is performed based on the playback signal.
Since the rotation control of CLV is performed, the rotation control of CLV suitable for the purpose is performed at the time of recording and reproduction.

Also, at the time of reproduction, the recording start and recording end absolute address values recorded in a predetermined area of the optical disc are read by the address management unit. The absolute address value of the current playback area is
The control means determines whether the recorded area or the unrecorded area is compared with the read absolute value of the recording start and recording end addresses. If the control means determines that the area is an unrecorded area, as a suboptimal measure, the CLV control based on the reproduction signal is switched to the CLV control based on the prerecorded signal using the position information even during reproduction. As a result, stable CLV control can always be realized even when the reproduction area approaches the unrecorded area from the recording area. Therefore, the problem that the rotation control cannot be performed during reproduction does not occur.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

As shown in FIG. 2, the magneto-optical disk 1 as a rewritable optical disk has a TOC (Table O
f Contents) area 1a is provided and TOC area 1a
Most of the area outside the area is the information recording area 1b.
In the information recording area 1b, various information such as a music program is recorded, while in the TOC area 1a, additional information regarding each information recorded in the information recording area 1b, for example, recording start and end positions of each information, etc. Is being recorded.

As shown in FIG. 3, in the TOC area 1a and the information recording area 1b of the magneto-optical disk 1, spiral or concentric guide grooves 2, 2 ... (Hatched for convenience) are predetermined in the disk radial direction. It is formed at intervals. Then, after the bi-phase modulation, the absolute address of each part on the disk is either "1" or "0", and the guide grooves 2 ... Are located inside the magneto-optical disk 1 in the radial direction. , Or biased outward. The above absolute address is the prerecorded information as the rotation control information.

As shown in FIG. 4, the optical disk recording / reproducing apparatus according to the present embodiment irradiates the magneto-optical disk 1 with laser light at the time of recording and reproducing, and a spindle motor 3 which supports and rotates the magneto-optical disk 1. An optical head 4 and a coil 5 for applying a magnetic field to the magneto-optical disk 1 during recording are provided. The present optical disc recording / reproducing apparatus is configured to perform recording by a so-called magnetic field modulation method, and is capable of overwriting by recording new information over recorded information.

The optical disk recording / reproducing apparatus includes an input terminal 6 for inputting information to be recorded, and analog information input from the input terminal 6 is an A / D (analog / digital) converter 7.
After being converted into a digital signal by the recording signal processing circuit 8
In the above, predetermined processing such as EFM (Eight Fourteen Modulation) modulation is performed and provided to the coil driver 10. The coil driver 10 drives the coil 5 based on the supplied signal, and at the same time, the optical head 4 irradiates the magneto-optical disk 1 with laser light to record a signal.

FIG. 5 shows a signal recording format. This format is conventionally used in CDs, and the music number and time information of the music information are recorded for each data field d in which 8 bytes of error correction parity is added to the signal of 24 bytes of music information. A frame a configured by adding a subcode c indicating the frame and a frame synchronization signal b indicating the beginning of the frame
Are recorded continuously. On the other hand, the subcode c in the TOC area 1a contains at least the recording end position of each information or the length from the recording start position to the recording end position with respect to the information such as the recording start position of each information in the read-only CD format. Information such as Sa is newly included.

The reproduction system will be described below. In FIG. 4, the signal reproduced by the optical head 4 is amplified by the reproduction amplifier 11.
The amplified signal is sent to the prerecorded information detection circuit 12 and the reproduction signal processing circuit 16.

The prerecorded information detection circuit 12 is composed of, for example, a bandpass filter and a phase-locked loop, and a clock synchronized with the phase-locked loop is generated for the prerecorded information in the reproduction signal extracted by the bandpass filter. It has become. Then, the frequency of the clock synchronized with the pre-recorded information composed of the bi-phase mark modulation of the absolute address and the first reference frequency supplied from the first oscillator 13 are compared by the first comparator 14, and the difference signal is switched. It is supplied to the container 15. Further, the present apparatus is provided with a pre-recorded information demodulation unit (not shown), and the pre-recorded information demodulation unit performs bi-phase mark demodulation at the time of access or the like, and the address decoder 22 in the address management unit indicates position information. Decoded into an absolute address. The address management unit has a configuration including an address decoder 22 and a TOC memory 23. And
The controller 24, which will be described later, recognizes the absolute address as the prerecorded information based on the result of the address decoder 22. The recording start absolute address value and the recording end absolute address value in the previous term are passed through the pre-recorded information detection circuit 12, the address decoder 22, the controller 24, the TOC memory 23, the recording signal processing circuit 83, the coil driver 10, and the coil 5. The data is recorded in the TOC area 1a which is a predetermined area on the magneto-optical disk 1.

In the reproduction signal processing circuit 16, the magneto-optical signal component in the reproduction signal supplied from the reproduction amplifier 11 is subjected to EFM demodulation and other predetermined processing, and the reproduction-processed signal is D / A (digital / digital).
It is adapted to be output to the outside through an (analog) converter 17 and an output terminal 18.

Further, the reproduction signal processing circuit 16 supplies a synchronization signal detection pulse indicating that the frame synchronization signal has been detected in each frame in the reproduction signal to the second comparator 20, where the synchronization signal detection pulse is supplied. The cycle is compared with the second reference frequency supplied from the second oscillator 19, and the difference signal is sent to the switch 15. When the reference frequencies of the first oscillator 13 and the second oscillator 19 are the same, the first oscillator 13 and the second oscillator 19 can be shared and a single oscillator can be used. Also, the first oscillator 13
If the reference frequency of 1 and the second reference frequency of the second oscillator 19 are in an integral multiple relationship, a single oscillator may be used and the frequency of this oscillator may be appropriately divided by a frequency divider. good.

The signal processed by the reproduction signal processing circuit 16 is sent to the TOC memory 23 in the address management section, and the recording start absolute address value and the recording end absolute address value recorded at the time of recording are reproduced by the optical head 4 at present. Is compared with the absolute address value of the playback area. The controller 24, which will be described later,
From the contents of the TOC memory 23, it is determined whether the optical head 4 is currently reproducing the recorded area or the unrecorded area.

The optical disk recording / reproducing apparatus according to the present invention is a controller
The recording means is provided with a control means such as 24, and when recording a signal, the recording operation is performed according to the flow shown in FIG. That is, as shown in FIG. 4, the switching device 15 is switched to the side of the first comparator 14 and the CLV is set based on the prerecorded information.
While performing control (S1), the recording start absolute address value at this time is stored in the TOC memory 23 (S2), and music information and the like are recorded. When the recording of the music information and the like is completed, the recording end absolute address value is stored in the TOC memory 23 at that time (S3). Then, the additional information of the recording start absolute address value and the recording end absolute address value is recorded in the TOC area 1a of the magneto-optical disk 1 via the recording signal processing circuit 8, the coil driver 10, and the coil 5 (S4). . On the other hand, when the signal is reproduced, the switching device 15 is set to the second comparator.
It is configured to switch to the 20 side and perform CLV control based on the reproduction signal.

Further, according to the flow shown in FIG. 1 (b), the control means reproduces the TOC area 1a which is a predetermined area of the magneto-optical disk 1 before reproducing the signal and starts recording. And the recording end absolute address value (recording area information) is read through the reproduction signal processing circuit 16 and stored in the TOC memory 23 (S1). Then, the absolute address value of the reproduction area obtained by reproducing the prerecorded information recorded in advance on the magneto-optical disk 1 is compared with the recording area information stored in the TOC memory 23 (S2). Then, it is determined whether the reproduction area is a recorded area or an unrecorded area (S3).
For example, when the absolute address value of the reproduction area obtained by reproducing the prerecorded information is equal to or more than the recording start absolute address value and equal to or less than the recording end absolute address value, the reproduction area is determined to be the recording area. Along with this, the switch 15 remains connected to the second comparator 20, and rotation control with a constant linear velocity is performed based on the reproduction signal (S4). On the other hand, when the absolute address value of the reproduction area is smaller than the recording start absolute address value or larger than the recording end absolute address value, it is determined as an unrecorded area. Accordingly, the switching device 15 is switched from the second comparator 20 to the first comparator 14 (S5). As a result, the rotation control with a constant linear velocity based on the reproduction signal is switched to the rotation control with a constant linear velocity based on the prerecorded information. Therefore, if CLV control based on the playback signal becomes difficult due to approaching an unrecorded area during playback, the CLV control (S5) based on prerecorded information is performed even during playback as the next best countermeasure. Therefore, there is no problem that CLV control cannot be performed during playback.

In the above embodiment, an example in which the absolute address on the magneto-optical disk 1 is biphase-modulated has been described, but the present invention is not limited to this, and another modulation method with limited frequency band may be used. .

Further, in the above embodiment, the magneto-optical disk 1 is mentioned as an example of the optical disk, but the present invention can be applied to a rewritable optical disk such as a phase change optical disk or a write-once optical disk. It is possible.

In the above embodiment, the absolute address as the pre-recorded information is recorded by displacing the guide grooves 2, 2, ... However, it may be meandered. Further, instead of this, the absolute address may be recorded in advance by the concave and convex pits. In that case, the CLV control based on the pre-recorded information may be performed by comparing the cycle in which the pits are reproduced with a predetermined reference frequency.

Further, in the above embodiment, the unrecorded area in the information recording area 1b has been described as an unrecorded area, but it can be applied to a recorded area or an unnecessary area or an unstable area.

〔The invention's effect〕

As described above, the optical disk recording / reproducing apparatus according to the present invention is an optical disk recording / reproducing apparatus for performing recording or reproduction on an optical disk in which rotation control information for performing rotation control at a constant linear velocity is recorded as pre-recorded information over the entire surface. In the above, at the start of the recording operation, the recording start absolute address value obtained from the pre-recorded information is stored, and at the end of the recording operation, the recording end absolute address value obtained from the pre-recorded information is stored. Rotation control is performed at a constant linear velocity using pre-recorded information, and the above-mentioned recording start and recording end absolute address values stored in the address management unit are recorded in a predetermined area of the optical disc. While controlling the rotation at a constant linear velocity, the above recording start and And the recording end absolute address value are read to the address management unit and compared with the absolute address value of the area being reproduced to determine whether the area is a recorded area or an unrecorded area. A control means for switching from the constant linear velocity rotation control based on the reproduction signal to the constant linear velocity rotation control based on the pre-recorded information is provided.

As a result, during recording, rotation control is performed at a constant linear velocity based on pre-recorded information, and during reproduction, rotation control is performed based on the reproduction signal. Control comes to be performed.

Further, when the reproduction area is determined to be an unrecorded area having an absolute address value other than the recording start and recording end absolute address values recorded in a predetermined area of the optical disc during reproduction, the next best As a countermeasure against this, the CLV control based on the playback signal was switched to the CLV control based on the pre-recorded signal using position information even during playback, so when the playback area approaches the recorded area to the unrecorded area, etc. Moreover, stable CLV control can always be realized. Further, in order to determine the recorded area and the unrecorded area, only absolute address values are compared, so that it is not necessary to provide a new detecting means, and the circuit configuration can be simplified.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention. FIG. 1A is a flowchart showing the procedure of CLV control during recording. FIG. 1B is a flowchart showing the procedure of CLV control during reproduction. FIG. 2 is a schematic plan view of the magneto-optical disk. FIG. 3 is an enlarged plan view of the magneto-optical disk. FIG. 4 is a block diagram of the optical disk recording / reproducing apparatus. FIG. 5 is an explanatory diagram showing a signal recording format. Reference numeral 1 is a magneto-optical disk (optical disk), 22 is an address decoder (address management unit), 23 is a TOC memory (address management unit), and 24 is a controller (control means).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihisa Deguchi, 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (56) References JP-A-64-37764 (JP, A) JP-A-62 -281162 (JP, A) JP 62-231465 (JP, A) JP 62-118781 (JP, A) JP 63-83958 (JP, A)

Claims (1)

[Claims] 1. An optical disc recording / reproducing apparatus for recording or reproducing information on or from an optical disc on which rotation control information for controlling rotation at a constant linear velocity is recorded as pre-recorded information over the entire surface. An address management unit that stores the recording start absolute address value obtained from the above, and also stores the recording end absolute address value obtained from the above-mentioned pre-recording information at the end of the recording operation; While performing rotation control, the above recording start and recording end absolute address values stored in the address management unit are recorded in a predetermined area of the optical disc, and during reproduction, rotation control is performed at a constant linear velocity based on the reproduction signal. , The recording start and end absolute address values from the specified area of the optical disc Reading the section, by comparing the absolute address value of the region being played, and determines whether the recording area or an unrecorded area,
Optical disc recording, characterized in that it is provided with control means for switching from rotation control with a constant linear velocity based on a reproduction signal to rotation control with a constant linear velocity based on the pre-recorded information when it is determined to be an unrecorded area. Playback device.