JP2001155342A - Optical disk recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in an optical disk such that a reproduced signal is remarkably deteriorated when the signal recorded at the 2nd time is reproduced, and also the actually usable capacity of the disk is decreased when the quality of the signal recorded at the 2nd time is defective. SOLUTION: In an application system 110, the overwriting recording is made on the optical disk 101 by the verifying operation when reproduced data from the optical disk 101 are not coincident with the recorded data. After that, the same address is reproduced by a front end 1 to check in a signal processing circuit 106 whether the quality of the reproduced signal shows the specified value or better. When the quality of the reproduced signal shows less than the specified value, each part is controlled by a system controller 108 so as to record again the same address, and the quality of the reproduced signal is again checked in the same way as the above. When overwritten more than twice, the signal quality of the better reproduced signal is held as compared with the reproduced signal of the overwriting recording at the 1st time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording and reproducing apparatus, and more particularly to an optical disk recording and reproducing apparatus for recording information on an optical disk using a phase change medium.

[0002]

2. Description of the Related Art In recent years, there has been remarkable progress in optical discs for recording and reproducing information using a laser beam due to advances in semiconductor laser technology. Initially, there was only a read-only disk as an optical disk, but as the light intensity of the semiconductor laser increased, some disks could be recorded.

The wavelength of light emitted from a semiconductor laser is 78
When a laser beam near 0 nm is used, a recordable optical disk includes an optical disk having a form called a compact disk (CD), and one of them is a CD-R called a write-once optical disk that can be written only once. , Number 1
As rewritable discs capable of recording about 00 times, there are CD-E, CD-RW and the like using a phase change recording material.
There is also an optical disk called a CD-MO using a magneto-optical recording material that can be rewritten tens of thousands of times. Like this
There are optical disks on which various types of recording can be performed depending on the recording material.

Recently, the semiconductor laser technology has advanced, and a laser having a wavelength of 650 nm has been put to practical use for an optical disc. As a result, the optical disc has a higher density than that of a compact disc.
A disk system called (Digital Versatile Disc) has begun to spread. As a recordable disc in DVD, a write-once optical disc DV that can be recorded only once is used.
An optical disk called a DVD-RAM or DVD-RW using a phase-change recording medium that has a DR and that can record and erase several hundred times is available.

[0005]

In the above-mentioned conventional example, the optical disk has a basic structure from the past to the present, despite the fact that the storage capacity of the disk has been increased due to the shortening of the laser beam used and the disk has been easy to use. There are the following issues that are not resolved in the following.

[0006] In a recordable optical disk, particularly in an optical disk using a phase change material as a recording material, when a signal recorded on the optical disk for the first time is reproduced, good reproduction signal characteristics are exhibited. In other words, when recording is performed again, that is, when the signal recorded for the second time is reproduced, there is a disadvantage that the reproduced signal is greatly deteriorated. This phenomenon depends on the composition of the recording medium and the like, and the quality of the recorded signal is not good both at the time of the third recording and at the time of the fourth recording.
At the time of reproduction, the error rate of the signal increases.

The recording material development department has been trying to develop a recording material which does not have such a phenomenon. However, even though the recording medium may be improved, such a recording medium which eliminates such signal deterioration when recorded a plurality of times is eliminated. Does not yet exist.
As a feature of this phase change type recording medium, the signal does not deteriorate much after rewriting and recording about 5 times until rewriting and recording about several thousand times. The disadvantage that the signal is deteriorated only at the time of rewriting recording is extremely uneconomical as a recording disk.

[0008] A further disadvantage is that if the quality of the signal recorded the second time is poor in the conventional recording machine, that location is not used as a recording location again, so that the second recording, the Despite the fact that a good signal can be recorded and reproduced again,
It has a fatal disadvantage that it is not used as a recording location. Further, when the signal quality of the reproduced signal at the recording location is poor when the signal is overwritten, the location is not used again.
The actual recording capacity of the disc decreases.

[0009] The present invention has been made in view of the above points,
An object of the present invention is to provide an optical disk recording / reproducing apparatus capable of performing sufficiently satisfactory recording / reproducing when information is rewritten on an optical disk (phase-change optical disk) using a phase change medium.

It is another object of the present invention to provide an optical disk recording / reproducing apparatus capable of securing a sufficient recording capacity for a long period of time.

[0011]

In order to achieve the above object, the present invention provides an optical disk recording / reproducing apparatus for recording and reproducing information on a phase change optical disk, after recording desired information on the phase change optical disk. A comparing means for performing a verify operation for reproducing and comparing the reproduced information with the original recorded information; and a verify operation, when the reproduced information and the original recorded information are inconsistent with each other, to the same recording location. Overwriting means for overwriting the same recording information, checking means for checking whether the reproduction signal quality of the overwritten information is equal to or higher than a predetermined value, and at least one when the reproduction signal quality is lower than the predetermined value. More than once, rewriting means for rewriting the same recording information at the same recording location is provided.

According to the present invention, the phase-change type optical disk is
Attention is paid to the fact that when the overwriting is performed more than once, a better signal quality of the reproduced signal can be maintained as compared with the reproduced signal of the first overwriting, and for example, the information recorded for the second time (the information recorded for the first overwriting) If the reproduction signal quality is poor, the operation of overwriting again at the same place is performed again, so that the reproduction signal quality can be improved.

In order to achieve the above object, the present invention is characterized in that the rewriting means of the present invention repeats a rewriting operation until the signal quality of reproduced information of rewritten recording information becomes a predetermined value or more. And In the present invention,
The overwriting operation can be performed while checking whether the reproduction signal quality has been improved.

Further, according to the present invention, in order to achieve the above object, even when the number of repetitions of the rewriting operation by the rewriting means in the above invention reaches a predetermined number, the reproduced signal quality of the rewritten recorded information is not less than a predetermined value. If not, the address of the recording location is regarded as a defect, and the recording information is recorded in another location on the phase-change optical disc. According to the present invention, the overwriting operation and the check of the reproduction signal quality are repeated many times as compared with the related art, so that the number of times that the area is regarded as a defect area can be significantly reduced as compared with the related art.

[0015]

Next, an embodiment of the present invention will be described. The present invention is an epoch-making invention that attempts to fully exploit the performance of a phase-change optical recording disc that has sufficient rewritable recording performance but cannot fully exhibit the performance.

An embodiment of the present invention will be described in detail. The phase-change type optical disk has a groove for recording and tracking guide formed on a substrate made of optically transparent plastic or glass. The grooves may be continuous or discontinuous.

A groove having a continuous groove controls the rotation of the disk at the time of recording, and is generally called a wobble for clarifying a recording position. is there. The meandering period of the groove may be different from the meandering period of the groove surface on the inner peripheral side of the disk and the meandering period of the groove wall surface on the outer peripheral side of the disk. The groove that is continuous like this is
This is a disc suitable for recording continuous information. In this wobble, address information for clarifying the recording location is inserted, and the ATIP signal (Absolu
te Time In Pregroove).
There is also a method of recording address information by increasing the width of a part of a groove, and there is also a method called a land pre-pit (Land Pre Pit).

On the other hand, in the case where the groove is discontinuous, a signal called a wobble is inserted into the wall surface of the groove. Each signal is basically used as in a hard disk or a floppy disk. The groove is interrupted for each sector, and address information is recorded at the beginning of each sector. The information to be recorded may be inside a groove (groove recording), between grooves (land recording), or inside and outside a groove (land groove recording).

As the phase change recording medium, a known phase change recording medium can be used. For example, GeSbT
e, InSbTe, AgSbTe, AgInSbTe, and the like. Generally, a protective layer is provided in contact with the phase change recording medium. The protective layer exists as layers above and below the layer change recording medium, and includes magnesium (Mg), calcium (Ca),
Strontium (Sr), yttrium (Y), lanthanum (La), cerium (Ce), titanium (Ti), zirconium (Zr), tantalum (Ta), zinc (Zn),
Silicon (Si), Germanium (Ge), Lead (Pb)
Oxides, sulfides, and nitrides are used.

The thickness of the phase change recording film is desirably about 10 to 100 nm. Such a phase change recording film and a protective layer are formed on a recording / tracking guide groove formed on the optically transparent plastic substrate or the like by a vacuum sputtering apparatus. Then, a metal film made of aluminum (Al) or an alloy thereof is formed as a reflective layer. Thus, each layer of the phase change recording type optical disk is formed. Recently released D
In VD, two disks prepared in this way are prepared and bonded with an adhesive with the recording surface inside, or one is bonded with a substrate called a dummy substrate that can not record signals etc. I have.

In order to record an information signal on an optical disk using a phase change medium (phase change type optical disk), an optical head for recording and reproduction is used. A sequence program called a strategy executed by a combination of a programmed time and a laser beam intensity is used. This strategy is described as a combination of the irradiation pulse time and the irradiation intensity of the laser beam in the specification of the corresponding optical disc.

In a phase change optical disk, after a recording medium is formed, the medium is in an amorphous state. In this state, the light reflectance is low. Thereafter, an initialization process is performed. The initialization processing is an operation of irradiating a recording medium on a disk with a strong laser beam to bring the recording film into a crystallized state. The initialization operation is generally performed while rotating the phase-change optical disk, and is much larger than the light spot diameter of about 1 μm used for recording and reproduction. For example, the spot diameter in the tangential direction of the disk reproduction is 20 μm and the spot diameter in the radial direction is the same. This is performed using a device equipped with a high-power laser for initialization, which has a spot diameter of about 200 μm.

Depending on the intensity of the laser beam used for the initialization operation and the time during which a certain portion of the recording medium is irradiated, the recording medium goes into a crystallized state through a temperature rise and a cooling state, and is relatively compared with an amorphous state. High reflectivity. The performance of the recording medium greatly depends on the initialization conditions at the time of this initialization. It is considered that this is due to the residual stress amount in the recording medium due to the temperature at the time of temperature rise of the recording medium, the temperature decreasing rate at the time of cooling, and the like.

The phase-change optical disk whose initialization has been completed is
Generally used for recording and reproduction. The phase-change type optical disc on which the first recording has been performed can obtain a good reproduction signal characteristic even if any phase-change type recording medium is used.
Good playback signal characteristics generally mean jitter of the playback signal,
It is evaluated by measuring the error rate. In a phase change recording medium, for example, even if the reproduction output is used as an evaluation scale, the correlation coefficient with the actually recorded signal quality is not large, so that the measurement of jitter and error rate is practical.

The phase change type recording medium has a feature called a direct overwrite in which a second signal can be directly overwritten. This direct overwrite is made possible by devising the recording strategy described above. In this direct overwrite, an erasing mode of the recording medium is incorporated during the recording strategy, and the recording medium is erased in the erasing mode, and at the same time, a new recording state is obtained by the incorporated recording mode. This is the operation that has been performed. In other words, the light intensity of the recording laser beam is changed into three stages of the light intensity suitable for erasing, the light intensity suitable for recording, and the light intensity suitable for cooling the recording medium, and the irradiation time of the recording laser beam is changed. This is accomplished by intermittently irradiating the recording mark for a shorter time than the length at which the recording mark to be recorded is formed.

However, two signals above the first recorded signal
When the second recording is performed by direct overwriting, recording is generally performed in a state where the signal quality is deteriorated as compared with the first recording. Although the cause has not been clearly elucidated, it seems to be caused by the deformation of the recording mark shape due to the residual stress in the recording material composition. However, if the third signal is further overwritten on this state, the same signal quality as that of the second signal can be recorded. If the fourth signal is further overwritten, the signal which is slightly improved compared with the third signal is obtained. can get. In general, when overwriting a recording medium in this way, 2
There is a characteristic that the signal quality at the time of the second overwriting becomes the worst.
This feature can be improved by optimizing the medium composition or the initialization conditions, but is not eliminated at all.

The state of poor signal quality can be solved by the third overwriting on some media, and cannot be solved by overwriting 10 times, but the phase change recording medium has a certain degree of overwriting. Has a feature that the signal quality is improved by overlapping. The phase-change type recording medium overwritten until the degradation of the signal quality is solved can maintain a good signal quality up to about 1000 overwrites. The phase change type recording medium overwritten about 1000 times has the composition components in the medium segregated, and the signal quality is again degraded. Since the signal quality of the medium after the overwriting has been performed about 1000 times is degraded by the segregation of the medium components, the signal quality is not improved by the overwriting.

FIG. 4 shows the above-mentioned phase change type recording medium,
FIG. 7 is a diagram showing the number of rewrites and the reproduction signal characteristics at the same recording location when using a VD-RW disc, and the jitter and error rate indicating the reproduction signal quality are the worst in the signal quality at the time of the second overwriting; It can be seen that good signal quality can be maintained up to over 1000 overwrites, and that over 1000 overwrites does not improve signal quality due to segregation of medium components. As described above, in the phase change recording medium, a phenomenon occurs in which a signal is degraded at the time of several times of overwriting, so that the recording / reproducing operation which is generally performed is not completed before the recording medium reaches its original life. It may be handled as a good disk.

Here, the recording / reproducing operation generally performed will be described. When the recording device performs a recording operation and records information on the disk, the information is recorded on the disk for a certain information amount length such as each recording sector or each recording address, and then the recorded information is recorded. If the recorded information matches the recorded information with the specified quality or higher, it is determined that the information has been correctly recorded on the disc, and the next information is recorded in the next recording area. Go. If the recorded information does not have the specified level of quality, the information is recorded in another sector prepared in advance, which is called a substitute sector for this sector. When recording information on a disc in this way,
We are proceeding with the recording while checking that the recording was performed correctly.

As described above, in the conventional optical disk recording / reproducing apparatus, when the quality of a reproduced signal at a location where data has been recorded is poor, the location is used again without overwriting the location again. As a result, the actual used capacity of the disk was reduced each time overwriting was performed. On the other hand, according to the present embodiment, the phase-change type optical disk focuses on the fact that when overwriting is performed twice or more, a better signal quality of the reproduction signal can be maintained as compared with the reproduction signal of the first overwrite recording. For example, if the reproduction signal quality of the information recorded for the second time (information recorded by overwriting for the first time) is poor, an operation of overwriting again at the same place is performed again to check whether the reproduction signal quality has improved. Since the recording operation is performed while recording, the new location is not used only by one overwriting operation, and the entire information recording area of the optical disk can be used. Therefore, in the optical disc recording / reproducing apparatus according to the present embodiment,
Even when the same optical disk is used for a long time, a sufficient recording capacity can be secured.

[0031]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an optical disk recording / reproducing apparatus according to the present invention. The optical disk recording / reproducing apparatus shown in the figure constitutes a data storage system using a rewritable DVD-RW which is a kind of a phase change optical disk. When the data storage system is divided into two parts by an interface circuit 3, signal processing is performed. Front end 1, file system 11 from circuit 106 to optical pickup 102
1 to the application system 110 are called a back end 2. The back end 2 is realized by a personal computer (PC) 109.

The optical disk 101 uses the DVD-RW described above.
The optical pickup 102 is clamped on a turntable provided on a rotating shaft of the disk motor 103, is driven to rotate in a predetermined direction by the disk motor 103, and
Irradiates the laser beam so as to focus and follow the pregroove, and information is picked up from the reflected light. Further, at the time of recording on the optical disk 101, the optical pickup 102 changes the laser emission intensity according to the recorded information and writes the information on the optical disk 101.

Here, the format of the read-only DVD-ROM is an error correction block (E
Each sector is composed of 26 sync frames. A DVD-RW disc records a signal having the same physical data format as that of the DVD-ROM. As shown in FIG. 2, the grooves to be recorded are tracks 41, 42,
The wobble frequency is eight times (approximately 140 kHz) the sync frame of the DVD-ROM. In FIG. 2,
Pre-pits are formed on the lands 51 and 52 between the tracks 41, 42 and 43.

That is, one of the grooves shown in FIG.
At the apex of the first three periods of the wobble in the sync frame, a pre-pit (Land Pre-Pi) for 1 bit of sync and 2 bits of data is placed on an adjacent outer land.
t, hereinafter referred to as LPP). Wobble and LPP are detected by the push-pull signal of the optical pickup, and the detection signals are shown in FIG. The LPP contains ECC block address information on the disk, and the ECC block of the recording data is recorded in synchronization with this address.

Returning to FIG. 1, the preamplifier 104 amplifies the signal picked up from the optical disk 101 by the optical pickup 102, generates error signals necessary for focus control and tracking control, and generates a control circuit. 107, and reproduces the information signal engraved on the optical disc 101 and outputs it to the signal processing circuit 106.
Further, the wobble signal from the pre-groove of the optical disk 101 is reproduced to form a band-pass filter (BPF) 105.
And outputs it to the signal processing circuit 106 and the control circuit 107.

The preamplifier 104 further drives the laser diode of the optical pickup 102, emits the laser diode at a constant power required for reading information when reproducing the disk, and a signal processing circuit 106 when recording the disk.
The light emission power of the laser diode is changed in accordance with the recorded information from.

The control circuit 107 receives the error signal from the preamplifier 104, controls the focus and tracking of the optical pickup 102, and controls the rotation of the disk motor 103 so that the average frequency of the wobble signal becomes about 140 kHz. I do. Also, the control circuit 1
07 demodulates address information from the LPP signal and outputs it to the system controller 108. The control circuit 107 further moves the optical pickup 102 according to a command from the system controller 108 to search for a designated address. The system controller 108 controls the signal processing circuit 10
6, and the control circuit 10 while communicating with the control circuit 107.
7 is controlled, and information engraved on the optical disk 101 is obtained from the signal processing circuit 106.

By the way, one data file is stored in the PC 1
When recording from 09, the application system 110 in the PC 109 notifies the front end 1 of the recording start address, the recording data itself, and the capacity of the recording data through the file system 111 and the interface circuit 3. In accordance with this instruction, the system controller 108 controls each block in the front end 1 and records data on the optical disk 101 as described above.

Next, when the recording of this file is completed,
The reproduction of the recording signal of the optical disk 101 is performed, and the PC 10
The application system 110 in 9 compares the currently recorded data in the PC 109 with the reproduced data from the optical disk 101, and confirms that they match (this operation is called verify). If there is any data that does not match, the application system 110 sends the ECC including the error data through the file system 111 and the interface circuit 3.
A block address, data to be recorded, and a re-recording command are sent to the front end 1.

When the front end 1 receives this, the system controller 108 controls each unit as described above, and performs recording once to the designated address. Thereafter, the front end 1 reproduces the same address, and checks in the signal processing circuit 106 whether the quality of the reproduced signal is equal to or higher than a predetermined value. As the means for checking the quality of the reproduced signal, for example, means for measuring the jitter of the reproduced waveform, means for detecting an error rate before error correction, and means for verifying the data executed after error correction are effective.

The result of checking the quality of the reproduced signal is notified from the signal processing circuit 106 to the system controller 108. In the first check of the reproduction signal quality, if the quality is equal to or more than the predetermined value, the recording to the address here is completed. If the quality is equal to or less than the predetermined value, the system controller 108 controls each unit so as to record the same address again, and checks the reproduction signal quality again as described above.

As described above, the system controller 108 performs the verification for each recording, and continuously performs the verification up to 10 times. If recording and verifying are performed up to 10 times and the reproduction signal quality does not exceed a predetermined value, the system controller 108 regards the address as a defect, and
A predetermined process such as recording data at a substitute address is performed. By doing so, the recording / reproducing jitter is particularly deteriorated by the second to several times of overwriting, which has been a problem in the past, and an error has occurred, which was regarded as a defect area. Be treated.

As described above, the DVD-RW as an embodiment of the present invention
Although an example using a disk has been described, other phase change recording media such as a DVD-RAM and a CD-RW
And the like can be implemented, and the same effect as the effect shown in this embodiment can be obtained.

In the above embodiment, the PC 109
The recording management function of the above application system 110 and file system 111 is required.
It is, of course, possible to respond without increasing the burden on 09.

[0045]

As described above, according to the present invention,
If the quality of the reproduction signal of the information recorded on the phase-change optical disc for the second time (the information recorded by overwriting the first time) is poor, for example, the operation of overwriting again at the same place is performed, thereby improving the reproduction signal quality. Therefore, the entire information recording surface of the disc can be used more effectively than a conventional device in which this area is unusable as a defect only by overwriting in the related art.

Further, according to the present invention, the overwriting operation is performed while checking whether or not the reproduction signal quality has been improved. Therefore, the number of overwriting operations is kept to a minimum and signal recording with good reproduction signal quality is performed. Can be performed quickly.

Further, according to the present invention, by repeating the overwriting operation and the check of the reproduction signal quality a large number of times as compared with the prior art, the number of times to be regarded as the defect area is greatly reduced as compared with the conventional one. Even when used for a long time, a sufficient recording capacity can be secured as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a track configuration diagram recorded in a physical data format of the optical disc in FIG. 1;

FIG. 3 is an explanatory diagram of a wobble and an LPP.

FIG. 4 is a diagram showing the number of times of rewriting and reproduction signal characteristics when a DVD-RW disc is used.

[Explanation of symbols]

 Reference Signs List 1 front end 2 back end 3 interface circuit 101 optical disk 102 optical pickup 103 disk motor 104 preamplifier 105 BPF (bandpass filter) 106 signal processing circuit 107 control circuit 108 system controller 109 personal computer (PC) 110 application system 111 file system

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D090 AA01 BB05 CC05 DD03 DD05 EE05 EE11 FF26 FF27 FF31 FF36 KK06

Claims (3)

[Claims] 1. An optical disk recording / reproducing apparatus for recording and reproducing information on a phase change optical disk, wherein desired information is recorded on the phase change optical disk and then reproduced, and the reproduced information matches the original recorded information. Comparing means for performing a verifying operation for comparing whether or not the reproduction information and the original recording information do not match by the verifying operation; overwriting means for overwriting and recording the same recording information at the same recording location; Means for checking whether or not the reproduction signal quality of the overwritten information is equal to or higher than a predetermined value; and if the reproduction signal quality is lower than the predetermined value, the check means checks the reproduction signal quality at least once or more at the same recording location. An optical disk recording / reproducing apparatus, comprising: rewriting means for rewriting recording information. 2. The rewriting device according to claim 1, wherein the rewriting means repeats the rewriting operation until the signal quality of the reproduced information of the rewritten recording information becomes equal to or higher than the predetermined value.
An optical disk recording / reproducing apparatus according to claim 1. 3. When the reproduction signal quality of rewritten recording information does not exceed the predetermined value even when the number of repetitions of the rewriting operation by the rewriting means reaches a predetermined number, the address of the recording location is regarded as a defect. 3. The optical disk recording / reproducing apparatus according to claim 1, wherein the recording information is recorded in another location of the phase change optical disk.