JPH0719431B2 - Optical disc recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical disk recording / reproducing apparatus for recording or reproducing information on a so-called write-once or rewritable optical disk, 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 mechanically recorded as digital signals by pits have been 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)
By collating the absolute address of the recording start position of each information recorded in the le Of Contents area, the continuous reproduction of the desired information, the selective reproduction, etc. are performed.

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 disk recording / reproducing apparatus by making the reproducing system common between them. In that case, a so-called constant linear velocity control (hereinafter, referred to as CLV (Constant Linear Velocity) control), which is carried out by a CD, can be adopted as an optical digital rotation control method during recording or reproduction. .

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 detected 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, the guide groove of the optical disk is radially inward or outward depending on whether each bit is “1” or “0” after the bidirectional mark modulation of the absolute address. 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 disk by using the information such as the absolute address previously recorded on the optical disk, the CLV at the time of recording is actually
Due to a control error or the like, information may be recorded in a state slightly deviated 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. Therefore, when reproducing information, it is preferable to perform CLV control based on the reproduced information.

However, during reproduction, for example, if a reproduction error frequently occurs, or if the optical head approaches an unrecorded portion of information, there is a problem that rotation control based on reproduction information becomes impossible. Further, even after the rotation control by the reproduction information becomes impossible once, even if the reproduction signal quality is restored, it takes a considerable time until the correct rotation control can be performed.

[Means for Solving the Problems]

In order to solve the above problems, an optical disk recording / reproducing apparatus according to the present invention records or reproduces on / from 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 optical disc recording / reproducing apparatus for performing the above, a reproduction signal state determining means for determining a reproduction signal state at the time of reproduction, a rotation control of a constant linear velocity using the above-mentioned prerecorded information at the time of recording, and a reproduction signal at the time of reproduction are performed. While performing the rotation control with a constant linear velocity, the control means for switching the rotation control at the time of reproduction to the rotation control based on the prerecorded information when the reproduction signal state determination means determines that the reproduction signal state is equal to or less than a predetermined reference. It is characterized by being provided.

[Work]

According to the above configuration, at the time of recording, the linear velocity constant (CLV) rotation control is performed based on the pre-recorded information, and at the time of reproduction, the CLV rotation control is performed based on the reproduction signal. At the time of reproduction, suitable rotation control is performed according to the purpose.

In addition, when the reproduction signal state determination means detects that the reproduction speed is difficult due to a reproduction error occurring frequently or the optical head approaches an unrecorded portion to obtain a reproduction signal during reproduction. Is the next best measure
Since the rotation control is switched to the rotation control based on the pre-recorded information even during the reproduction, the problem that the rotation control cannot be performed during the reproduction does not occur.

[Embodiment 1] The following will describe one embodiment of the present invention with reference to FIGS. 1 to 6.

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 information recording area 1b is outside the area. 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 position and recording end position of each information. Etc. are to be 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 mark modulation, the absolute address of each part on the disc is biased inward or outward in the radial direction according to whether it is "1" or "0". There is. 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 EFM (Eight Fourteen Modulation), predetermined processing is performed and supplied 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 clock frequency synchronized with the pre-recorded information composed of the bi-phase mark modulated wave 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 to recognize the value of the absolute address as the pre-recorded information as needed at the time of access. It is a thing.

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 transferred to the D / A (digital / analog) converter 17 and It is adapted to be output to the outside through the 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 synchronization 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. When the first reference frequency of the first oscillator 13 and the second reference frequency of the second oscillator 19 are in an integral multiple relationship, a single oscillator is used and the frequency of this oscillator is divided by a frequency divider. Alternatively, the frequency may be appropriately divided.

The signal processed by the reproduction signal processing circuit 16 is sent to the reproduction signal state judging circuit 21 as a reproduction signal state judging means, where whether the magneto-optical signal recorded on the magneto-optical disk 1 is reproduced properly. Whether or not the optical head 4 is currently reproducing the recorded area is determined.

The optical disk recording / reproducing apparatus is provided with a control means such as a controller (not shown), which switches the switching device 15 to the first comparator 14 side at the time of recording a signal, as shown in FIG. The recording operation is performed (S2) while the CLV control is performed based on the pre-recorded information (S1). That is, in this case, the difference signal of the first comparator 14 is sent to the spindle motor 3 via the switch 15, and the clock frequency synchronized with the bi-phase mark modulated wave of the absolute address as the pre-recorded information and the first oscillator. The CLV control is performed so that the first reference frequency from 13 matches.

Further, as shown in FIG. 1 (b), when the signal is reproduced,
The reproduction signal state determination circuit 21 detects the reproduction signal state (S1), and the control means stabilizes whether or not the reproduction signal state is good (S2), and the currently recorded area is reproduced. If the playback signal state is good, the CLV control is switched to the playback signal side and the playback operation is performed (S3). That is, the difference signal from the second comparator 20 is supplied to the spindle motor 3 via the switch 15, and the period of the sync signal detection pulse supplied from the reproduction signal processing circuit 16 and the second signal from the second oscillator 19 are supplied. CLV control is performed so that it matches the reference frequency. Therefore, even if there is a slight variation in linear velocity during recording, the amount of signal reproduced per unit time during reproduction is constant.

In addition, if the unrecorded area is reached during playback, or
If the CLV control based on the playback signal becomes difficult due to the playback signal condition becoming worse due to frequent playback errors, etc., the CLV control based on the pre-recorded information even during playback is the next best measure. Since (S4) is performed, there is no problem that CLV control cannot be performed during playback.

Hereinafter, a more specific configuration of the reproduction signal state determination circuit 21 will be described. In the present embodiment, when the CLV control based on the reproduction signal is performed, the synchronization state becomes abnormal and the frame synchronization signal is continuously lost, or the optical head 4 approaches the unrecorded area of the information and the frame synchronization is performed. When the signal is continuously lost, this is detected, and the CLV control during reproduction is switched to the control based on the prerecorded information.

That is, as shown in FIG. 6, a reproduction signal state determination circuit
Reference numeral 21 includes a counter 22, a comparator 23 and a reference value supply circuit 24, and a sync signal detection pulse indicating that a frame sync signal is detected at a predetermined timing is supplied from the reproduction signal processing circuit 16 to the reset terminal of the counter 22. Meanwhile, the clock signal of the counter 22 is supplied with a sync signal missing pulse indicating that the frame sync signal is missing at a predetermined timing. As a result, the number of times the sync signal missing pulse is supplied is counted by the counter 22, while the counter 22 is reset when the sync signal detection pulse is supplied.

Then, the value of the counter 22 is compared by the comparator 23 with the reference value supply circuit.
When compared with the reference value supplied from 24, the value of the counter 22 exceeds the reference value from the reference value supply circuit 24, in other words, when the loss of the frame synchronization signal occurs a predetermined number of times or more, CLV control from the comparator 23 to the switcher 15 by assuming that there is a synchronization error in the recorded portion of the signal during CLV control based on the playback signal, or that the frame synchronization signal is not detected due to approaching the unrecorded portion. A control switching signal is output so that the CLV control by the pre-recorded information can be switched even during reproduction.

Second Embodiment Next, a second embodiment will be described.

The second embodiment has substantially the same configuration as that of the first embodiment except that the reproduction signal state determination circuit 21 is different from that of the first embodiment. For simplicity, only the reproduction signal state determination circuit 21 will be described below. In this embodiment, the reproduction signal state determination circuit 21 is configured to switch to CLV control based on prerecorded information even during reproduction when a reproduction error continuously occurs in the recorded portion of the information recording area 1b. ing.

That is, as shown in FIG. 7, a reproduction signal state determination circuit
21 is an inverter 25, two NANDs 26 and 27, and a counter 28
And a comparator 30 and a reference value supply circuit 31. The sync signal detection pulse is supplied from the reproduction signal processing circuit 16 to one input terminal of each of the NAND circuits 26 and 27. Further, from the reproduction signal processing circuit 16 via the inverter 25, the other input terminal of the NAND circuit 26, an error flag indicating whether or not a reproduction error has occurred in each frame is input, while the NAND circuit 27
The error flag is directly input to the other input terminal of. Therefore, when a reproduction error occurs in a certain frame and the error flag becomes High level, the value of the counter 28 is counted up by the signal supplied from the NAND circuit 27 to the clock terminal of the counter 28, while in the certain frame. When a reproduction error does not occur and the error flag becomes low level, the NAND circuit 26 supplies the signal to the reset terminal of the counter 28, and the counter 28 is reset based on the signal.

Then, the comparator 30 compares the value of the counter 28 with the reference value from the reference value supply circuit 31, and when the value of the counter 28 exceeds the reference value, in other words, continuously in a predetermined number of frames or more. When a playback error occurs, it is considered that the playback signal has deteriorated due to frequent playback errors, and the comparator 30
The CLV control switching signal is output. As a result, CLV control based on the prerecorded information is performed even during reproduction.

Third Embodiment Next, a third embodiment will be described with reference to FIGS.

In this embodiment, it is determined whether or not a phase shift has occurred in the phase-locked loop 35 included in the reproduction signal processing circuit 16, and if the phase shift has occurred, the CLV control is switched.

That is, as shown in FIG. 8, in this embodiment,
The reproduction signal processing circuit 16 includes a phase comparison circuit 32, a reduction pass filter (LPF) 33, and a phase locked loop (PLL) 35 including a voltage dependent oscillator (VCO) 34. on the other hand,
The reproduction signal state determination circuit 21 includes an edge detection circuit 36, a delay circuit 37, a D type flip-flop 38, a frequency determination unit 40, and an AND circuit 41. The edge detection circuit 36, the delay circuit 37 and the flip-flop 38 are a phase determination unit.
42 make up.

The reproduction binary signal 1 is supplied from the reproduction signal processing circuit 16 to the edge detection circuit 36, and the edge at the inversion position of "1" and "0" in the reproduction binary signal I is detected by the edge detection circuit 36, The edge signal II falling at the edge position is input to the clock input terminal CK of the flip-flop 38.

Further, the clock III output from the voltage-dependent oscillator 34 is supplied to the delay circuit 37, where 1/4 of the cycle of the clock III.
The delayed signal IV is input to the data input terminal D of the flip-flop 38 with a delay. Then, the phase determination signal V from the output terminal Q of the flip-flop 38 and the frequency determination signal VI from the frequency determination unit 40 are supplied to the AND circuit 41. The phase determination signal V and the frequency determination signal VI are at high level when the phase and frequency are appropriate, respectively, and CLV control switching is performed when the CLV control switching signal output from the AND circuit 41 is at low level. It is supposed to be done. The frequency determination unit 40 is configured to determine whether the frequency of the clock III is within the proper range.

FIG. 9 shows the signals I to V of the reproduction signal state determination circuit 21 described above.
Shows a time chart of. In the figure, (a) shows the transition of the reproduced binary signal I, (b) shows the transition of the edge signal II, and (c) shows the transition of the clock III. in this case,
The phase locked loop 35 is locked, and the reproduction binary signal I and the clock III are in phase with each other.

Alternatively, FIG. 9 (d) shows the transition of the delay signal IV,
(E) shows the transition of the phase determination signal V. As is clear from comparison between (b) and (d) in the figure, since the delay signal IV is always High at the fall of the edge signal II, the phase determination signal V output to the flip-flop 38 is Always high level.

Next, Fig. 10 shows the clock II of Phase Locked Loop 35.
The time chart when the phase of I is delayed is shown. In this case, the clock III in (c) of FIG.
However, it is delayed by (2/5) cycles. Therefore, the delay signal IV is always at the low level when the edge signal II falls, and thus the phase determination signal V is always at the low level.

FIG. 11 shows a time chart when the phase of the clock III of the phase locked loop 35 is advanced. In this case, the clock III in FIG. 7C leads the reproduced binary signal I by about (2/5) cycle. Therefore, the delay signal IV is always at the low level when the edge signal II falls, and thus the phase determination signal V is always at the low level.

[Fourth Embodiment] FIG. 12 shows a reproduction signal processing circuit 16 and a reproduction signal state judging circuit 21 in a fourth embodiment.

This embodiment is effective when a so-called DC-free reproduction binary signal has a signal format in which both "1" and "0" energy densities are approximately 50%. It is determined whether or not the state is proper, and if the reproduction signal state is bad, the CLV control is switched to the CLV control based on the prerecorded information.

The reproduced binary signal from the reproduced signal processing circuit 16 is supplied to one input terminal of the NAND circuit 43 and also supplied to one input terminal of the NAND circuit 45 via the inverter 44. Also, NAND
The pulse from the oscillator 46 is input to the other input terminal of the circuits 43 and 45, and the output signal of the NAND circuit 43 is output to the addition side input terminal of the up / down (U / P) counter 47. The signal is input to the subtraction side input terminal of the up / down counter 47. Thus, if the reproduction binary signal is "1" when the pulse is input from the oscillator 46, the up-down counter 47 is counted up, and if the reproduction binary signal is "0", the up-down counter is
47 is counted down.

Then, the comparator 48 compares the value of the up / down counter 47 with the reference value supplied from the reference value supply circuit 50, and the value of the up / down counter 47 exceeds the reference value. Therefore, the energy density of the reproduced binary signal is increased. It is considered that the reproduction signal state is deteriorated when an abnormality occurs in the
The CLV control switching signal is output.

[Fifth Embodiment] Next, a reproduced signal state judging circuit 21 in a fifth embodiment will be described with reference to FIG.

In this embodiment, when the optical head 4 approaches an unrecorded area during reproduction, the CLV control is switched to the CLV control based on the prerecorded information.

That is, the reproduction signal state determination circuit 21 includes an envelope detection circuit 51 and a comparator 52. The reproduced signal state determination circuit 21 is supplied with the analog reproduced signal before binarization from the reproduced signal processing circuit 16 of FIG.

Then, the envelope detection circuit 51 performs envelope detection of the analog reproduction signal, the detected signal is compared with the reference voltage Vc by the comparator 52, and when the envelope-detected signal is smaller than the reference voltage Vc, in other words, , CL when the optical head 4 is located in the unrecorded area where no reproduction signal is detected
The V control switching signal becomes a low level, and it is possible to switch to CLV control based on prerecorded information even during reproduction.

[Sixth Embodiment] Next, a reproduction signal state judging circuit 21 in a sixth embodiment will be described with reference to FIG.

Also in this embodiment, when the optical head 4 is located in the unrecorded portion in the information recording area 1b during reproduction, the CLV control is switched based on the prerecorded information.

That is, the reproduction signal state determination circuit 21 includes the edge detection circuit 53.
And a retriggerable monostable multivibrator 54, and the reproduction binary signal from the reproduction signal processing circuit 16 is input to the edge detection circuit 53. The time constant of the retriggerable monostable multivibrator 5 is
For example, it is set to be slightly longer than the maximum length of the edge interval of the reproduced binary signal shown in FIG. 9B (for example, 11 channel bits for the EFM signal). Therefore, when the optical head 4 is located in the recorded portion of the information recording area 1b of the magneto-optical disk 1 and the reproduction binary signal is input to the edge detection circuit 53, the retriggerable monostable multivibrator 54 is used. Is retriggered at any time, the CLV control switching signal output from the retriggerable monostable multivibrator 54 is always at high level, and CLV control switching is not performed.

On the other hand, when the optical head 4 is located in the unrecorded portion of the information recording area 1b of the magneto-optical disk 1 and the reproduced binary signal is not input to the edge detection circuit 53, the edge detection is not performed and therefore the read Since the triggerable monostable multivibrator 54 is not triggered, the CLV control switching signal from the retriggerable monostable multivibrator 54 becomes low level, and the CLV control is switched to the CLV control based on the prerecorded information even during reproduction.

In the above embodiment, an example in which the absolute address on the magneto-optical disk 1 is biphase-mark modulated has been described.
The present invention is not limited to this, and other modulation schemes with limited frequency bands 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.

Further, in the above-mentioned embodiment, the absolute addresses as the prerecorded information are recorded by displacing the guide grooves 2.2, but instead, the guide grooves 2.2 may be meandered. Further, instead of that, 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.

〔The invention's effect〕

As described above, the optical disk recording / reproducing apparatus according to the present invention is an optical disk recording 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 prerecorded information over the entire surface. In the reproducing apparatus, a reproducing signal state judging means for judging a reproducing signal state at the time of reproducing, a rotation control of a constant linear velocity using the above-mentioned pre-stored information at the time of recording, and a constant linear velocity on the basis of the reproducing signal at the time of reproducing. While the rotation control is performed, there is provided control means for switching the rotation control during reproduction to the rotation control based on the prerecorded information when the reproduction signal state determination means determines that the reproduction signal state is equal to or less than a predetermined reference. It is a composition.

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 it is detected by the reproduction signal state determination means that the rotation speed based on the reproduction signal becomes difficult due to a reproduction error occurring frequently or the reproduction signal is not obtained due to reaching the unrecorded portion during reproduction, As a good measure, since the rotation control is switched to the rotation control based on the prerecorded information even during reproduction, the problem that rotation control cannot be performed during reproduction does not occur.

[Brief description of drawings]

1 to 6 show a first embodiment of the present invention. FIG. 1A is a flowchart showing the procedure of CLV control during recording. FIG. 11B 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. FIG. 6 is a block diagram showing a main part of the optical disk recording / reproducing apparatus. FIG. 7 is a block diagram showing the main part of the optical disk recording / reproducing apparatus in the second embodiment. 8 to 11 show the third embodiment. FIG. 8 is a block diagram showing a main part of the optical disk recording / reproducing apparatus. 9 to 11 are time charts showing transitions of signals around the phase locked loop. 12 to 14 are block diagrams showing the main parts of the optical disk recording / reproducing apparatus in the fourth to sixth embodiments, respectively. Reference numeral 1 is a magneto-optical disk (optical disk), and 21 is a reproduction signal state determination circuit (reproduction signal state determination 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 an optical disc having rotation control information for controlling rotation at a constant linear velocity over the entire surface as pre-recorded information, wherein a reproduction signal state during reproduction is recorded. A reproduction signal state generating means for making a determination and a rotation control of a constant linear velocity using the above-mentioned pre-recorded information at the time of recording, and a rotation control of a constant linear velocity based on the reproduction signal at the time of reproduction, while a reproduction signal state An optical disk recording / reproducing apparatus comprising: a control unit that switches the rotation control during reproduction to the rotation control based on the pre-recorded information when the determination unit determines that the reproduction signal state is equal to or less than a predetermined reference.