JP2001210024A - Disk-like recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent medium from running away by surely detecting a read-out area in a disk-like recording medium such as a MiniDisk(MD) and a recordable/ reproducible compact disk (CD-MO). SOLUTION: An outermost read-out area 3 of a disk is a magneto-optical area. Thus, when a pickup arrives at the read-out area 3 from a data area being the magneto-optical area, the data of the read-out area 3 are reproduced without switching a regenerating signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk-shaped recording medium for recording and reproducing digital audio signals, for example, and more particularly to a recordable and reproducible CD-MO.
The present invention relates to a disk-shaped recording medium suitable for use as a disc or a mini disc (MD).

[0002]

2. Description of the Related Art A so-called compact disk (CD) in which an audio signal is digitized and recorded on an optical disk has become widespread. FIG. 4 shows a configuration of an optical disk 101 used as a conventional compact disk. The conventional compact disc has an outer diameter of, for example, 12 cm, and as shown in FIG.
2 are provided, and a lead-out area 103 is provided on the outermost periphery. The area between the lead-in area 102 and the lead-out area 103 is a data area 104. The lead-in area 102 is provided with a TOC (Table Of Contents) for recording data position information. A predetermined pattern is recorded in the lead-out area 103.
Music data and the like are recorded in the data area 104. This music data is so-called straight PCM audio data obtained by simply linearly quantizing an analog audio signal. In such a conventional compact disc, the lead-in area 102, the lead-out area 10
3. Data is recorded in the data area 104 in all pits.

In such a conventional disk reproducing apparatus for reproducing a compact disk, when a disk is loaded, first, the lead-in area 102 is accessed, and the TOC information in the lead-in area 102 is read.
A desired data position is accessed using the TOC information, and the recorded data is reproduced. When the pickup reaches the outermost lead-out area 103, a desired pattern recorded in the lead-out area 103 is reproduced. As a result, the pickup is
1 is detected to have reached the outermost circumference.

[0004] The above-mentioned conventional compact disc is dedicated to reproduction, and cannot record data. Therefore, a rewritable write-once CD-WO and a recordable / reproducible CD-MO using a magneto-optical disk have been proposed. As shown in FIG. 5, a data area 204 is formed between a lead-in area 202 and a lead-out area 203 on a recordable and reproducible CD-MO magneto-optical disk 201. In the lead-in area 202, TOC data is recorded by pits, and in the lead-out area 203, a predetermined pattern is recorded by pits. In the data area 204, desired data can be recorded / reproduced by the mark of the magnetization direction of the perpendicular magnetization film.

In such a CD-MO, the lead-in area 202 and the lead-out area 203 are areas where data is recorded by pits (hereinafter referred to as pre-master areas), and the data area 204 is the magnetization of the perpendicular magnetization film. An area in which data is recorded (hereinafter, referred to as a magneto-optical area) is defined by the direction mark. Therefore, it is necessary to switch the reproduction signal from the pickup. That is, the reproduction signal of the pre-master area is obtained from the level of light reflected from the disk, and the reproduction signal of the magneto-optical area is
It is obtained by detecting the direction of the car rotation angle. That is, the reproduction signal of the premaster area is obtained from the sum signal of the two optical detectors of the pickup, and the reproduction signal of the magneto-optical area is obtained from the difference signal between the two optical detectors of the pickup. For this reason, the lead-in area 202 and the lead-out area 20 composed of the pre-master area
In No. 3, it is necessary to output the sum signal of the two photodetectors of the pickup, and in the data area 204 consisting of the magneto-optical area, it is necessary to output the difference signal of the two photodetectors of the pickup.

FIG. 6 shows an example of a reproduction signal switching circuit. In FIG. 6, output terminals RF1 and RF2 of two optical detectors of a pickup are connected to input terminals 251 and 252, respectively.
Are supplied respectively. The reproduction signals RF1 and RF2 from the input terminals 251 and 252 are supplied to the addition circuit 253 and to the subtraction circuit 256. Adder circuit 253
Then, the outputs RF1 and RF2 of the two photodetectors are added. In the subtraction circuit 256, the outputs RF1 and RF2 of the two photodetectors are subtracted. The output S _RF of the adding circuit 253 is supplied to a terminal 254A of the switch circuit 254. The output of the subtraction circuit 256 is supplied to a terminal 254B of the switch circuit 254. The output of the switch circuit 254 is output from the output terminal 255.

When the premaster area is being reproduced, the outputs RF1 and RF2 of the two photodetectors are in phase. The outputs RF1 and RF of the two photodetectors
When 2 is added by the addition circuit 253, a reproduced signal of a physical pit is obtained. Outputs obtained by subtracting the outputs RF1 and RF2 of the two photodetectors by the subtraction circuit 256 are canceled.

When reproducing a magneto-optical area, 2
The outputs RF1 and RF2 of the two photodetectors are out of phase. When the outputs RF1 and RF2 of the two photodetectors are subtracted by the subtraction circuit 256, a reproduction signal of the mark in the magnetization direction of the perpendicular magnetization film is obtained. The output obtained by adding the outputs RF1 and RF2 of the two photodetectors by the adding circuit 253 is canceled.

In FIG. 6, a switch circuit 254, which is a premaster area, has a terminal 254A for reproducing the lead-in area 202 and the lead-out area 203.
Set to the side. Thereby, the lead-in area 2 is obtained from the sum signal of the outputs RF1 and RF2 of the two optical detectors.
02 and the data in the lead-out area 203 are reproduced. When reproducing the data area 204 which is a magneto-optical area, the switch circuit 254 is connected to the terminal 254B.
Set to the side. Thereby, the data recorded in the data area is reproduced.

[0010]

In the conventional CD-MO disk, as shown in FIG.
03 is a pre-master area. However, if the lead-out area 203 is a pre-master area, it is not possible to detect that the pickup has reached a position outside the disk, and there is a risk that the servo will run away.

That is, when reproducing the data area, the switch 254 in FIG. 6 is set to the terminal 254B side, and the outputs RF1 and RF2 of the two optical detectors are set.
Is output. If the lead-out area 203 is a pre-master area, the data in the lead-out area 203 cannot be reproduced unless the switch circuit 254 is switched to the terminal 254A when the pickup reaches the outermost read-out area 203. Therefore, if the switch circuit 254 is not properly switched, a predetermined pattern in the lead-out area 203 cannot be reproduced even when the pickup reaches the outermost lead-out area 203, and the pickup may be displaced from the position of the disc. There is.

Accordingly, an object of the present invention is to provide a disk-shaped recording medium capable of reliably detecting a lead-out area and avoiding runaway of a servo.

[0013]

The present invention is a disk-shaped recording medium characterized in that a lead-out area is provided on the outer periphery of a disk, and the lead-out area is a recordable area.

According to the present invention, a lead-in area consisting of a pre-master area pre-mastered, a data area consisting of a magneto-optically recordable magneto-optical area, and a lead-out area consisting of a magneto-optically recordable magneto-optical area are provided. A disk-shaped recording medium provided from an inner periphery to an outer periphery.

By making the lead-out area a magneto-optical area, when the pickup moves from the data area to the lead-out area, it is possible to detect the lead-out recording pattern without switching the reproduction signal. For this reason, the lead-out can be reliably detected, and runaway of the servo can be prevented.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. The present invention is applied to an optical disc for recording and reproducing data-compressed music information. Examples of such a recordable optical disk include, for example, Japanese Patent Application No. 2-169977 filed by the present applicant,
Disks according to Japanese Patent Application Nos. 2-282121 to 2-222823 are preferable. In this disk, a magneto-optical disk or the like is used as a recording medium. For example, AD (adaptive difference) PCM audio data defined in an audio format of a so-called CD-I (CD-Interactive) or CD-ROMXA, or another format. The digital audio data bit-compressed and encoded according to the above is recorded and reproduced.

In such an optical disc, for example, so-called standard CD format data or so-called straight PCM audio data obtained by simply linearly quantizing an analog audio signal is bit-compressed to, for example, approximately 1/4. Recorded. For this reason, a recording and reproducing time of the same size as a standard 12 cm compact disc can be obtained with a smaller disc, and the apparatus can be downsized. In addition, the (instantaneous) bit rate of recording / reproducing
By using the same format as the D-DA format, the time required to actually write data to and read data from the disk can be reduced to approximately 1/4, respectively.
The remaining approximately 3/4 of the time can be allocated to processing such as so-called retry. Accordingly, recording and reproduction can be performed more reliably even under a bad condition in which the mechanical unit vibrates due to a disturbance and focus, tracking, or the like is lost, and application to a small portable device becomes possible.

FIGS. 1 and 2 show an embodiment of a disk to which the present invention is applied. 1 and 2
In the magneto-optical disk 1 to which the present invention is applied,
For example, its outer diameter is 64 mm. A lead-in area 2 is provided on the innermost circumference of the magneto-optical disk 1. The lead-in area 2 is provided with a TOC in which information on the disc (disc type, data area position, lead-out area position, etc.) is recorded. This lead-in area is a pre-master area. On the outermost periphery of the magneto-optical disk 1, a lead-out area 3 is provided. The lead-out area 3 is a magneto-optical area, and a predetermined pattern is recorded magneto-optically with a mark in the magnetization direction of the perpendicular magnetization film.

A user TOC indicating position information of data recorded in the data area 4 is provided on an outer periphery of the lead-in area 2.
An area 5 is provided. The area from the user TOC area 5 to the lead-out area 3 is the data area 4. The user TOC area and the data area 4 are magneto-optical areas. A groove is provided along the track in the magneto-optical area, and tracking control is performed using the groove, and address information is recorded as a wobble component in the groove. A technique for recording address information using a wobbling component of a groove as described above is disclosed in, for example, JP-A-63-87682 and JP-A-63-87655, and has been previously proposed by the present applicant.

In the data area 4 of the magneto-optical disk 1,
Bit-compressed digital audio data for a plurality of music pieces are recorded. The address information of each song (data file) is recorded, for example, in the user TOC area 5.

FIG. 3 is a block diagram showing a schematic configuration of a recording / reproducing apparatus for recording and reproducing data on the optical disk.

In FIG. 3, a bit-compressed digital audio signal for a plurality of music pieces (a plurality of data files) is recorded on the magneto-optical disk 1 as described above.
The magneto-optical disk 1 is driven to rotate by a spindle motor 11. The rotation of the spindle motor 11 is controlled by a spindle servo circuit 12 under the control of a system controller 13.

An optical pickup 14 and a magnetic head 15 for performing recording and / or reproduction on the magneto-optical disk 1 are provided. The optical pickup 14 includes, for example, a laser light source such as a laser diode, a collimator lens, an objective lens, an optical component such as a polarizing beam splitter, a cylindrical lens, and a photodetector having a light receiving unit having a predetermined pattern. The optical pickup 14 is provided with the magnetic head 1 via the magneto-optical disk 1.
5 is provided at a position facing the same.

When data is recorded on the magneto-optical disk 1, the magnetic head 1 is driven by the head drive circuit 16 of the recording system.
5 is driven to apply a modulation magnetic field corresponding to the recording data, and the optical pickup 14
Is irradiated with a laser beam. This allows
The magnetization direction of the perpendicular magnetization film is determined according to the direction of a magnetic field applied from the outside, and data is recorded magneto-optically. During reproduction, a laser beam is emitted from the optical pickup 14, and data is reproduced from the reflected light. In the pre-master area (a portion where data is recorded by physical pits and corresponds to the lead-in area 2), data is reproduced from the sum signal of the two detectors of the optical pickup 14. In a magneto-optical area (a part where data is recorded according to the magnetization direction of the perpendicular time film and corresponds to the lead-out area 3, the data area 4, and the user TOC area 5), the data is obtained from the difference signal between the two detectors of the optical pickup 14. Is played.

The outputs RF1 and RF2 of the two detectors from the optical pickup 14 are supplied to an addition circuit 17 and to a subtraction circuit 18. Adder circuit 17
Then, the outputs RF1 and RF2 of the two detectors are added. The output of the adder circuit 17 is supplied to a terminal 19A of the switch circuit 19. The premaster area is reproduced, and the outputs RF1 and RF of the two detectors are subtracted by the subtraction circuit 18.
2 is subtracted. The output of the subtraction circuit 18 is supplied to a terminal 19B of the switch circuit 19. When reproducing the magneto-optical area and outputting the sum signal of the outputs RF1 and RF2 of the two detectors, the switch circuit 19 is switched to the terminal 19A side. Output RF1 of two two detectors
In the case of outputting the difference signal of RF2 and RF2, the switch circuit 19 is switched to the terminal 19B side.

A focus and tracking servo circuit 20 for performing focus and tracking control of the optical pickup 14 is provided. The focus and tracking servo circuit 20 is controlled by the system controller 13.

At the time of data recording, an analog audio signal from an input terminal 21 is supplied to an A / D converter 23 via a low-pass filter 22. The A / D converter 23 digitizes the input analog audio signal. This digital audio signal is supplied to the data compression encoder 24.

The data compression encoder 24 performs a high-efficiency encoding process such as AD (Adaptive Difference) PCM on the digital audio signal obtained from the A / D converter 23. The digital audio signal input to the data compression encoder 24 is a so-called straight PCM
The data is, as a specific example, PCM data having a sampling frequency of 44.1 kHz and a quantization bit number of 16 bits, similarly to the standard CD (compact disk) format. This input audio PC
The M data is encoded by the data compression encoder 24, for example, according to the sampling frequency, the bit compression algorithm, and the combination of stereo / monaural as described above.
A high-efficiency encoding process may be performed such that the bit rate becomes / 2 to 1/16.

The output of the data compression encoder 24 is supplied to a memory 25. The memory 25 is controlled by the system controller 13 to write and read data, and temporarily stores bit-compressed data supplied from the encoder 13, and is used as a buffer memory for recording on a disk as necessary. Have been. That is, for example, in a data compression mode with a compression ratio of 4, compressed data of a constant bit rate reduced to approximately 1/4 of the data transfer rate (bit rate) of the standard compact disk format is stored in the memory 25. Written continuously.

When the compressed data is recorded on the magneto-optical disk 1, a burst or discrete operation is performed from the memory 25 at the same data transfer speed under the same disk rotation speed (constant linear speed) as in the standard CD-DA format. It is read out and recorded. That is, the time during which the signal is actually recorded in the recording mode is approximately 1/4 of the whole, and the remaining 3/4 time is a pause period during which no recording is performed.
However, on the magneto-optical disk 1, the next recording is performed following the area recorded immediately before the pause period, and continuous recording is performed on the medium surface. As a result, for example, recording of the same recording density and recording pattern as in the standard CD-DA format is performed.

The compressed data burst-read from the memory 25 at a bit rate corresponding to the data transfer rate of the standard CD-DA format is subjected to interleave processing, error correction coding processing, EFM modulation processing, and the like. Is supplied to the encoder 26. The output of the encoder 26 is supplied to the magnetic head drive circuit 16. A modulation magnetic field is generated from the magnetic head 15 by the output of the magnetic head drive circuit 16, and the modulation magnetic field is applied to the magneto-optical disk 1. At the same time, a laser beam is emitted from the optical pickup 14, and data is recorded in the data area 4 of the magneto-optical disk 1.

When data is recorded in the data area 4, address information of the recorded data is recorded in the user TOC area 5. As the address information recorded in the user TOC, the start address and the end address of each song are used. Further, the compression ratio information of the recording data can be recorded in the user TOC.

Next, a reproducing system of the disk recording / reproducing apparatus will be described. This reproducing system is for reproducing the recording data continuously recorded on the recording tracks of the magneto-optical disk 1 by the above-mentioned recording system. By tracing with the optical disk 1
The recording signal is read from.

As described above, in the premaster area,
The sum signal (R) of the two detectors of the optical pickup 14
F1 + RF2), data is reproduced. In the magneto-optical area, data is reproduced from the difference signal (RF1-RF2) between the two detectors of the optical pickup 14. This data recording / reproducing apparatus is provided with a judgment circuit 27 for judging whether the currently traced area is a pre-master area or a magneto-optical area.

The determination circuit 27 includes an addition circuit 28, a detection circuit 29, and a comparator 30.
The addition circuit 28 forms a sum signal of the two photodetectors of the optical pickup 14. The level of this sum signal is detected by the detection circuit 29. The output of the detection circuit 29 is supplied to the comparator 30. If the area currently being traced is the premaster area, the optical pickup 1
Since the reproduction signal is obtained from the sum signal of the two photodetectors 4 and 4, an output of a predetermined level or more is detected from the detection circuit 29. If the area currently being traced is a magneto-optical area, the sum signal of the two photodetectors of the optical pickup 14 becomes lower than a predetermined level. Therefore, it can be determined from the output of the converter 30 whether the currently traced area is the pre-master area or the magneto-optical area. This judgment output is supplied to the system controller 13.
A switch control signal is formed based on the determination output, and the switch control signal is supplied to the switch circuit 19.

Since the pre-master area and the magneto-optical area on the magneto-optical disk 1 can be obtained in advance from the lead-in information, the pre-master area and the magneto-optical area can be determined from their addresses. . However, the area cannot be reliably determined only from the address. By providing such a determination circuit 27,
The pre-master area and the magneto-optical area can be reliably determined.

The output of the switch circuit 19 is supplied to a decoder 31. The decoder 31 corresponds to the encoder 26 in the recording system described above, and performs processing such as deinterleaving processing, decoding processing for error correction processing, and EFM demodulation processing. The compressed data output from the decoder 31 is supplied to the memory 32.

The memory 32 is controlled by the system controller 13 to write and read data. The memory 32 reads and decodes the data in a burst from the magneto-optical disk 1 at the same data transfer rate as the standard CD-DA format. Is written. Then, the reproduction data written in a burst in the memory 32 is continuously read at a constant bit rate corresponding to the compression ratio.

The compressed data continuously read from the memory 32 is supplied to a data decompression decoder 33. The data expansion decoder 33 corresponds to the recording system encoder 24 and expands compressed data to reproduce 16-bit digital audio data. This decoder 3
The digital audio data from 3 is supplied to a D / A converter 34. The digital audio data is converted into an analog signal by the D / A converter 34. This analog audio signal is output from the output terminal 36 via the low-pass filter 35. Also, the decoder 33
Is output from a digital audio output terminal 38 via a digital output circuit 37.

[0040]

The magneto-optical disk 1 to which the present invention is applied
, The lead-out area 3 is a magneto-optical area. For this reason, the optical pickup 14 has the data area 4
, The recording pattern of the lead-out area 3 can be detected without switching the reproduction signal. For this reason, the switching control of the reproduction signal is simplified, the lead-out area 3 can be reliably detected, and the optical pickup 14 can be prevented from being displaced from the position of the disk.

Further, according to the present invention, since the lead-out area 3 is a magneto-optical area, the manufacture of the disk is simplified, and data can be recorded in the lead-out area 4.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a sectional view of one embodiment of the present invention.

FIG. 3 is a block diagram of an example of a magneto-optical disk recording / reproducing apparatus to which the present invention is applied.

FIG. 4 is a cross-sectional view of an example of a conventional optical disk.

FIG. 5 is a sectional view of another example of a conventional optical disk.

FIG. 6 is a block diagram used for explaining a reproduction system using a conventional optical disc.

[Explanation of symbols]

1 ... optical disk, 2 ... lead-in area, 3 ...
..Lead-out area, 4 ... data area, 5
..User TOC

Claims (4)

[Claims] 1. A disc-shaped recording medium, wherein a lead-out area is provided on an outer periphery of a disc, and the lead-out area is a recordable area. 2. A lead-in area consisting of a pre-master area pre-mastered, a data area consisting of the magneto-optically recordable magneto-optical area, and a lead-out area consisting of the magneto-optically recordable magneto-optical area. A disk-shaped recording medium provided from an inner periphery to an outer periphery. 3. The disk according to claim 2, further comprising a user inventory area for managing position information of data recorded in the data area, between the lead-in area and the data area. Recording medium. 4. The disk-shaped recording medium according to claim 3, wherein said user catalog area comprises a magneto-optical area capable of magneto-optical recording.