JP2586461B2 - Disk-shaped recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A. Industrial application fields B. Summary of the invention C. Conventional technology D. Problems to be solved by the invention E. Means to solve the problems F. Operation G. Example G-1. Format (FIGS. 1 to 4) G-2. Magneto-optical disk drive (FIG. 5) G-3. Specific Example (FIG. 6) H. Effects of the Invention A. Industrial Application Field The present invention relates to a disk-shaped recording medium such as a magneto-optical disk, and more particularly to a disk-shaped recording medium in which a time-division servo signal such as a so-called sector servo signal is recorded on a disk in advance.

B. Summary of the Invention The present invention is configured such that servo signal areas in which servo pits and the like are formed and data / address signal areas in which data and addresses are written are provided alternately along the circumferential direction of the disk. In a disk-shaped recording medium, signal recording by two or more kinds of physical changes can be performed in a data address signal area between servo signal areas, and signal recording in two or more kinds of recording forms is performed in one data address signal area. In this case, by forming a signal switching portion between these signal recording portions, a margin is provided for a switching time when reproducing a signal in each recording mode, and even if a data transfer speed is increased, the switching time is sufficient. This is to make it possible to respond.

C. Prior Art In recent years, disk-shaped recording media such as optical disks and magneto-optical disks utilizing an optical or magneto-optical signal recording / reproducing method have been developed and are being supplied to the market. These disc-shaped recording media can be roughly classified into three types of discs according to their recording forms. That is, similarly to a digital audio disk or a video disk such as a so-called CD (compact disk), various information signals are recorded in advance in a meter-side non-rewritable disk-shaped recording medium and supplied to a user. ROM (read
Only memory) type discs and so-called PROM (programmable RO), which is called DRAW or write-once type, and allows the user to write information signals only once
M) type disk and so-called RAM capable of erasing and rewriting information signals recorded like a magneto-optical disk
(Random access memory) type disks.

Each of these types of discs has been developed individually, and the development time is different, etc.
They use different formats. For this reason, compatibility between these types of discs cannot be obtained, and there are many disadvantages on both the user side and the maker side. Here, as one of the techniques for realizing this unified format, similarly to a so-called sector servo in a hard disk in the field of magnetic disks, concentric or spiral tracks on the disk are provided at predetermined intervals or Introduce the concept of so-called sampling servo, in which servo signals are recorded at predetermined intervals and continuous servo control is performed by sampling and holding these discrete servo signals during disk rotation drive. Has been proposed.

In this case, the disc of the unified format uses not only a case where the signal recording form of one disc is limited to one of the above-mentioned several recording forms but also a case where two or more kinds of recording forms are recorded on one disc. This includes those for which signal recording has been performed. For example, in a magneto-optical disk, the servo signal and the address signal are recorded and formed in advance by a so-called embossing process using mechanical pits and bumps, and magneto-optical recording of a data signal is performed by a user or the like. Is performed.

D. Problems to be Solved by the Invention By the way, in the above-described magneto-optical disk reproducing apparatus, reflected light from the recording surface and the like are separated by a polarizing beam splitter and detected by two photodetectors. The servo signal and the address signal recorded with the pits are obtained by adding the detection signals from the above, and the data signal recorded by the magneto-optical recording is obtained by subtracting each detection signal. In this case, the servo signal is processed by the servo signal circuit system based on the addition output, but the address signal and the data signal are time-divisionally processed by the signal processing system. In a converter input section or the like, a switching operation for switching and supplying an address signal and a data signal is required.

However, as shown in FIG. 7, in one data address signal area 4 between the servo signal areas 3 of one track 2, the address signal recorded by the pits and the like and the data by the magneto-optical recording are recorded. If the signal is recorded continuously, the above switching operation must be performed instantaneously at the time of transition from the address signal recording area to the data signal recording area during reproduction, and the time width of one window of the channel clock Switching is required in a time width shorter by an order of magnitude, especially when the disk is driven at a high rotational speed and the data transfer rate is increased, an extremely high-speed switching operation of about several nanoseconds is required, and the hardware burden is increased. It is large, difficult to implement, and expensive. FIG. 7 shows an arbitrary one-track recording mode. In contrast to the recording mode shown in FIG. 7A, pits P are formed as schematically shown in FIG. 7B. You.

In one data address signal area 4, it is conceivable to perform only signal recording by one kind of physical change. Since the number of bytes in the data / address signal area 4 is usually larger, two or more types of signal recording due to physical change may be mixed in one area 4 from the viewpoint of effective use of the recording area. It may be preferable.

Therefore, the present invention has been made in view of the above-described conventional problems,
In a disk-shaped recording medium capable of recording signals in two or more types of physical recording forms between servo signal areas, when reproducing the recording medium, a reproduction signal of one physical signal recording form is converted to another physical signal. It is an object of the present invention to provide a disk-shaped recording medium capable of switching a recording mode to a reproduction signal with a sufficient time.

E. Means for Solving the Problems In order to achieve the above object, a magneto-optical disk drive according to the present invention has a servo signal area in which a servo signal is recorded, at least a data signal, and a data in which an address signal is written. In a disk-shaped recording medium in which address signal areas are alternately provided along the circumferential direction of the disk, the data address signal area includes at least a signal recording due to a first physical change, Is recorded by a physical change of the servo signal area.
When signal recording portions due to the first and second physical changes are mixedly formed in one of the data address signal areas, reproduction from each signal recording portion is performed between these recording portions. A signal switching portion having a sufficient byte length for switching and outputting a signal based on the servo signal from the servo signal area is formed.

F. Function When signal recording by two or more types of physical changes is performed in one data address signal area, a switching portion provided between these recording portions has a margin for reproducing signal. Switching can be performed.

G. Embodiment Hereinafter, an embodiment in which the present invention is applied to a magneto-optical disk will be described with reference to the drawings.

FIG. 1 schematically shows a recording mode of an arbitrary track 2 of the magneto-optical disk in the present embodiment, and a pit P like B is formed in a recording mode of A.
In FIG. 1, between each servo signal area 3 in which a servo signal is recorded in the form of a pit, a data / address signal area 4 in which a data signal and an address signal are written is provided. Are provided alternately along tracks 2 in the circumferential direction of the disk. In the data address signal area 4, at least recording of an address signal by forming a pit as a first physical change,
When a general data signal is recorded by magneto-optical recording as a physical change, and when both the address signal and the data signal are recorded in one data address signal area 4, these recording portions 5a, During 5b, the signal switching part
5c is interposed.

G-1. Recording Format (FIGS. 1 to 4) Here, the recording pattern on the magneto-optical disk and the recording form of the track in the present embodiment will be described in more detail.

First, in FIG. 2, in the case of a so-called 5-inch type, for example, the magneto-optical disk 1 has a diameter of about 13 cm,
It has a storage capacity of 0 MB or more. This disk 1
Is rotated at a constant angular velocity, and data is recorded by forming a track 2 concentrically, for example, as one track per rotation. The number of tracks on one side is about 18000 to 20000, and each track is divided into, for example, 32 sectors. As shown in FIG. 1, each track 2 includes a servo signal area 3 in which servo pits are recorded and a data / address signal area 4 in which data signals and address signals are written. And these are provided alternately along the circumferential direction. In one sector, several tens of sets of these servo signal areas 3 and data / address signal areas 4 are provided. Each length of the servo signal area 3 and the data address area 4 is, for example, 2 bytes and 16 bytes, respectively, when converted into bytes.

Then, each of the above servo signal area 3, as shown in FIG. 3, three pits P _A, P _B, P _C are formed. Pits P _A, P _B is formed with a shift in the vertical direction across the center line of the tracks formed on the disc 1 (dashed line), also the pit P _C are formed on said center line. Each of these pits P _A, P _B, the diameter of P _C 0.5 to 1.0
μm, and the actual length L of the servo signal area 3 is, for example, about 15 to 30 μm. Also in the FIG. 4, the pits P _A in the (arrow direction in FIG. 2) the radial direction of the disk 1, P _B, are shown arrangement of P _C. That is, the pits P _B, P _C are arranged in a straight line respectively, the pits P _A is located in every n-number (e.g., 16) are arranged one behind the longitudinal direction of the track. The every n in the array of the pits P _A, which shifted position, traverse described later for the optical pickup to seek a track number currently being scanned
Used to count. Where the pit P
_A is the sample pulse SP ₁ or sample pulses SP ₂ sampled, and each pit P _B, P _C are respectively sampled by the sample pulse SP _3, SP _5, further of the pits P _B and pits P _C mirror surface area between is sampled by the sample pulse SP _4, is used for various servo and clock generation, which will be described later. That is, the servo signal of the present embodiment is used for each control operation of focusing, tracking, clocking, and traverse counting.

Next, at least an address signal and a data signal for each sector are recorded in the area 4 between the servo signal areas 3. As an example, when the effective data of one sector is 512 bytes, data of about 670 to 680 bytes in total is recorded in one sector by adding additional information and error detection / correction codes. If is 16 bytes, 1
In order to configure sector data, for example, 42 or more areas 4 are required. For example, 42 of the 43 data recording areas 4 are used exclusively for data recording, and one is used for recording addresses and data.

Here, as a gist of the present invention, in the case where recording of a recording form due to two or more types of physical changes is mixed in one area 4, a signal switching portion is interposed between signal recording portions due to these physical changes. Is always interposed. That is, in this embodiment, when the address signal and the data signal are mixedly recorded in the data / address signal area 4, the signal switching part 5c is provided between the address signal recording part 5a and the data signal recording part 5b. Is formed. The length of the address signal recording portion 5a and the length of the data signal recording portion 5b are a bytes and b bytes in bytes, respectively. Next, the address signal recording portion 5a
The c-byte of the length of the signal switching portion 5c provided immediately after is set to a length sufficient to effectively perform a signal switching operation at the time of reproduction, which will be described later. Specifically, for example, if the length is about 1 byte, Good. This signal switching portion 5c may be a blank portion in which nothing is recorded, and additional data not required at the time of data reproduction or the like, for example, pit formation of DDM (data deleted mark) for the address data, etc. May be recorded. Further, in the address signal recording portion 5a, address information and the like for each sector are previously recorded and formed in the form of pits similar to the servo signal, and in the data signal recording portion 5b, the additional information and error information are recorded. Broadly defined data signals including detection / correction codes can be recorded in a so-called magneto-optical manner.

G-2. Magneto-optical disk device (FIG. 5) Next, the overall configuration of a magneto-optical disk device for recording / reproducing the magneto-optical disk of the present embodiment will be described with reference to FIG.

In the Figure 5, the input terminal 11, the data D _I is supplied for example to be recorded via the interface from a computer or the like. The data D _I is subjected to predetermined modulation containing sent to the modulation circuit 12 bit conversion, and the like has been performed, are sent to the laser drive circuit 13. The laser drive circuit 13 is supplied with a control signal in each mode of writing, reading or erasing from the interface, outputs a signal for driving the laser diode 2 of the optical pickup 20 in response to the control signal, and outputs data. A drive pulse signal having a timing corresponding to a channel clock CCK serving as a reference clock is supplied to the laser diode 21 at the time of recording and erasing, and a high-frequency drive signal is supplied at the time of reading.

The optical pickup 20 includes the laser diode 21
In addition, it comprises a photodiode 22 and two photodetectors 23 and 24 divided into four. The photodiode 22 detects the intensity of the laser light emitted by the laser diode 21. The photodetectors 23 and 24 detect, for example, the reflected light of the laser light from the magneto-optical disk 1 via an analyzer. One of the photodetectors 23 and 24 detects the positive component of the car rotation angle, and the other detects the reflected light. The minus direction component of the car rotation angle is detected.

The motor 14 is servo-controlled by, for example, a PLL (Phase Locked Loop) by a motor servo circuit 15, and rotates the disk 1 accurately at a predetermined speed (angular speed).

Then, the laser beam output from the laser diode 21 irradiates the magneto-optical disk 1 and enters the photodiode 22. The output of the photodiode 22 according to the light intensity of the laser light is supplied to a sample-and-hold (S / H) circuit 17 via a DC amplifier circuit 16. In the S / H circuit 17, the sample pulse SP ₄ (fourth
The sample-and-hold operation is performed in response to the output of the laser drive circuit 13 via the APC amplifier circuit 18.
Is supplied as an APC (Automatic Power Control) control signal. Thus, the light intensity of the laser light output from the laser diode 21 is kept at a predetermined value.

The optical pickup 20 into which the reflected light of the laser light from the disk 1 is incident via an analyzer (not shown).
Are output to the preamplifier circuit 31, respectively. From the preamplifier circuit 31, a photodetection signal S _A (S _A = A + B + C + D + A ′ +) is a sum signal of the outputs from the respective light receiving regions of the photodetectors 23 and 24.
B '+ C' + D ' ) ( together containing a DC component) are sent directly to the focus servo circuit 32, the light detection signal and an output by the respective light receiving regions S _{B [S B = (AC-BD)} +
(A'C'-B'D ')], via the S / H circuit 33 for sampling and holding operation in response to the sample pulse SP ₄ is sent to the focus servo circuit 32. Then, a focus servo control signal generated by the focus servo circuit 32 based on the signals S _A and S _B is sent to the optical pickup 20, and focus control is performed.

Further, the light detection signal S _C (S _C =
A + B + C + D + A '+ B' + C '+ D') are sent to a peak position detection circuit 41, S / H circuits 51, 52, 53 and a sampling clamp circuit 61, respectively. Above light detection signal
S _C is the detection signal of the pit pattern or irregular pattern in the servo signal area 3 and the address signal area 4a of the disk 1. In the peak position detecting circuit 41, the peak position of the light detection signal S _C is detected, further, at unique pattern detection circuit 42 on the disc 1 the pits
P _B, by detecting the pit pattern with a spacing given uniquely only between P _C performs detection of the pits P _C, the detection output is sent to the generator 44 via a delay circuit 43. Then, in the pulse generating circuit 44, based on the detection output obtained by the above specific pattern detection circuit 42, the pit P _C
Channel clock CCK as reference clock synchronized with
As well as generating the byte clock BYC, servo byte clock SBC and sampling pulses _{SP 1, SP 2, SP 3} , SP
_4. SP ₅ is formed and output (see FIG. 4). Although not shown, the channel clock CCK is supplied to all circuit blocks. The sample pulse SP ₁ is supplied to the S / H circuit 51, sample pulse SP ₂ is supplied to the S / H circuit 52, sample pulse SP ₃ is supplied to the S / H circuit 52. Also, sampling pulses SP ₄ is is supplied to the S / H circuits 17 and 33, is supplied to the sampling clamp circuits 61 and 62. Incidentally, the sample pulse SP ₅ is used for detection of the moving direction of the optical pickup 20, for example. Further, a gate pulse is supplied from the pulse generation circuit 44 to the peak position detection circuit 41 and the unique pattern detection circuit 42.

In each of the S / H circuit 51, 52 and 53, the sample-and-hold operation at each sample pulses SP _1, SP _2, SP ₃ is performed on the light detection signal S _C fed. The output from the S / H circuit 51 and the output from the S / H circuit 52 are
4 compares the levels. The comparison output is in relation to the radial direction of the sequence on the disc 1 of the pits P _A inverted every above n tracks (e.g. 16 tracks), and sent to the tracking servo / seek circuit 55 as a signal for the traverse count Is sent to the multiplexer 56. From the multiplexer 56, the above S / H circuits 51, 5
The signal with the higher level among the signals from 2 is selectively output and sent to the subtraction circuit 57. In the subtraction circuit 57,
A difference signal between the signal from the multiplexer 56 and the signal from the S / H circuit 53 is formed and sent to the tracking servo / seek circuit 55 as a tracking error signal. The tracking servo / seek circuit 55
Performs tracking control and feed control of the optical pickup 20.

Then, the light detection signal S _C to the sampling clamp circuit 61, also = light detection signal S _D [S _D to the sampling clamp circuit 62 (A + B + C + D) - (A '+
B ′ + C ′ + D ′)] are respectively supplied from the preamplifier circuit 31. This light detection signal _SD is
This is a detection signal of data written in the data area 4b of the disk 1. In contrast, the light detection signal S _C that is supplied to the sampling clamp circuit 61 is a detection signal of the address stored in the region 4a. Each signal is clamped respectively by the sample pulse SP ₄ in each sampling clamp 61 the multiplexer 63
Sent to

The switching selection operation of the multiplexer 63 is controlled by a control signal from a synchronization detection / address decode circuit 64. For example, first, the light detection signal S _C via the sampling clamp circuits 61 and a multiplexer 63 analog-to-digital (A / D) converter 65
If the output from the demodulation circuit 66 is sent to a synchronization detection / address decoding circuit 64, a synchronization signal (sink) is detected. The address information is decoded. Then, according to the address information of the data to be read supplied from the computer or the like via the interface, the multiplexer 63 is switched when the address information and the actual address match, thereby controlling the light detection signal S for the data area 4b. _D is a / D converter 65 is sent to the demodulation circuit 66, the data D _O obtained by performing demodulation processing including the bit conversion from the output terminal 67 are outputted. This data _DO is sent to a computer or the like via the interface. When writing data, the synchronization detection / address code circuit 64 is used.
Is transmitted to the modulation circuit 12, and data to be written from the modulation circuit 12 is transmitted to the laser drive circuit 13 in accordance with the control signal.

Here, the switching control operation of the multiplexer 63 is performed within the scanning time of the signal switching portion 5c in the one area 4. As described above, the signal switching portion 5c is set to about 1 byte, so that the multiplexer 63 can be switched with a sufficient time margin even if the disk rotation speed increases and the data transfer rate increases.

G-3. Specific Example (FIG. 6) Next, the above-described address signal recording portion 5a, data signal recording portion 5b, and signal switching portion between these recording portions.
A specific example of the data address signal area 4 in which 5c is currently formed will be described with reference to FIG.

In FIG. 6, for example, a 1-byte sector mark SM is recorded in the address signal recording portion 5a in the data address signal area 4 between the servo areas 3, and following the sector mark SM, respectively. The upper byte T _M , the lower byte T _L , and the sector number S of the track number for each byte are recorded together with these inverted data _M , _L. In the example of FIG. 6, the order of recording is T _M ,
_{Although M} , _TL , _L , and S are used, they may be recorded in any other order. For example, S, _TM , _TL , _L , _M , and
May be recorded in this order. As described above, these address data are, of course, pre-format data recorded and formed in advance in a so-called pit form on the medium.

Immediately after the address signal recording portion 5a, for example, a signal switching portion 5c as an address post mark APM is provided. The signal switching portion 5c may be a blank portion in which no recording is performed, and may be used as a DDM (data deleted mark) of an address indicating a deletion area when a defect or the like is found at the time of preformatting the address data. It may be used.

The address post mark APM which is the signal switching portion 5c
Is followed by a data signal recording portion 5b. In this data signal recording portion 5b, for example, copy protect data CP and data deleted mark DDM of 1 byte each are respectively written with inverted data ▲ ▼, ▲
Recorded together with ▼, these 4-byte data
Following CP, ▲ ▼, DDM, ▲ ▼, 1-byte data indicating the data type (for example, 2 bits indicating whether or not the file is a real-time file, general computer data,
(Consisting of 6 bits indicating whether the data is audio data or video data). The DDM is used when the data type recorded in the data recording area 4 is a PROM (programmable ROM) type.

It should be noted that the present invention is not limited to only the above embodiment, and various changes can be made without departing from the spirit of the present invention. For example, signal recording by three or more types of physical changes is possible. It goes without saying that the present invention can be easily applied to a possible disk-shaped recording medium.
Further, the number of bytes in one sector, the number of bytes in each of the servo signal area and the data / address signal area, and the like are not limited to the numerical values in the above-described embodiment, and can be set arbitrarily.

H. Effects of the Invention According to the disk-shaped recording medium according to the present invention, when there are two or more types of signal recording modes due to physical change on one disk, the recording mode is changed from one recording mode to another recording mode. Since the switching is performed in the signal switching portion, there is no need to instantaneously perform the signal switching at the time of reproduction. Even if the data transfer rate increases, the signal switching can be performed with sufficient time, and the hardware load can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a recording form of each track on a disk-shaped recording medium according to one embodiment of the present invention, FIG. 2 is a schematic diagram showing a recording pattern of a magneto-optical disk in the above embodiment, and FIG. Schematic diagram showing the configuration of each pit area,
FIG. 4 is a schematic diagram showing the arrangement of pits that also exist along the radial direction of the disk, and FIG. 5 shows the overall configuration of an example of a magneto-optical disk device using the disk-shaped recording medium according to the present invention. FIG. 6 is a block diagram, FIG. 6 is a schematic diagram showing a specific example of recorded contents in one data address signal area in the embodiment of the present invention, and FIG. 7 is a schematic diagram showing a recording form of each track for explanation of the present invention. FIG. 1 ... Magneto-optical disk 2 ... Track 3 ... Servo signal area 4 ... Data / address signal area 5a ... Address signal recording section 5b ... Data signal recording section 5c ... Signal switching section

Claims (1)

(57) [Claims] 1. A disk-shaped recording device comprising a servo signal area on which a servo signal is recorded and a data address signal area on which at least a data signal and an address signal are written are provided alternately along the circumferential direction of the disk. In the medium, the data address signal area includes at least a first
And a signal recording by a second physical change is performed, and the first physical change recorded and formed in one data address signal area between the servo signal areas is performed. Between the signal recording portion due to the second physical change and the signal recording portion due to the second physical change, based on the servo signal from the servo signal area, to output the reproduced signal from the signal recording portion. A disk-shaped recording medium comprising a signal switching portion having a byte length.