JPH05290384A - Optical disk - Google Patents

Abstract

PURPOSE:To perform the measurement of reflectivity more accurately by providing a reflecting area with diameter larger than the beam spot diameter of an optical beam converged on a disk at the prescribed position of a data recording area. CONSTITUTION:An optical disk 2 is housed in a cartridge 31, and the recording and reproducing device of the optical disk 2 is equipped with an optical head 3 for recording/reproduction. A magnetic head 4 is fixed on an arm 51 whose one terminal is supported in such a way that it can be turned freely, and the head 4 nutates on the surface of a rotating optical disk 2. A signal read out from the optical disk 2 by the optical head 3 goes to an audio signal compressed by a data compression/expansion circuit 41 in which compression processing is applied to data, and read out signal data is stacked at a transfer rate of around five times by a DRAW 40, etc., and is demodulated by the LSI of the data compression/expansion circuit 41. Plural reflecting areas with diameters larger than the beam spot diameter of the optical beam converged on the disk 2 are provided at the prescribed position of the data recording area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recordable optical disk such as a magneto-optical disk.

[0002]

2. Description of the Related Art An optical disk can have a recording capacity about 2-3 times larger than that of a magnetic disk, can be accessed at a higher speed than a tape-shaped recording medium, and can record data without contacting the medium. Since it has the advantages of being reproducible and having excellent durability, it has been widely used in recent years. For this optical disc,
The so-called CD (compact disc) is most widely known.

By the way, a portable type using an optical disc,
Particularly, when it is intended to provide a so-called pocket-sized headphone stereo device or a recording and / or reproducing device similar thereto, for example, in the existing CD as described above, the disc diameter is 12 cm and the disc diameter is 8 cm. Although "so-called CD single" is specified in the format, a disk with a diameter of 12 cm uses a disk with a diameter of 8 cm or smaller because the outer size of the recording / reproducing device becomes too large and portability is poor. Can be considered. However, this 8 cm
There are the following problems when a portable or pocket-sized recording and / or reproducing apparatus is constructed by using an optical disc having a small diameter of about the same or less.

First, the sampling frequency is 44.1 kHz.
Stereo digital PC quantized by 16 bits in z
In a standard CD format (CD-DA format) in which an optical disc on which an M audio signal is recorded is supplied from the manufacturer side and only reproduction is performed on the user side, the reproduction time (recording time of a disc having a diameter of 8 cm ) Is as short as 20 to 22 minutes at maximum, which means that one classical music symphony cannot be recorded.
Therefore, it is desired that the reproduction time is about 74 minutes at maximum, which is the same level as the current 12 cm CD. Also, this CD-
In the DA format, recording cannot be performed on the user side. Further, since the non-contact optical pickup head is vulnerable to mechanical vibration and the like, track deviation and focus deviation are likely to occur due to vibration and the like. Therefore, when the device is carried, reproduction due to these track deviation and focus deviation occurs. Some kind of cooperative measure is required to suppress the adverse effect on the operation.

Next, the standard CD format (C
C as an extended format of D-DA format)
The D-MO format (format that uses a recordable magneto-optical disk) has a recording / reproducing time of 20 minutes for a disk having a diameter of 8 cm, which is the same as the CD-DA format.
It takes about 22 minutes, which is short. Further, similarly to the above, a track shift or a focus shift of the optical pickup head due to mechanical vibration or the like is likely to occur, and a measure is required to prevent adverse effects on the recording and reproducing operations due to the shift.

In the CD-I (CD-interactive) format and the CD-ROM / XA format, the modes of level A, level B, and level C are modes for recording / reproducing a bit-compressed digital audio signal. Is specified.

For example, when reproducing a disc recorded in the level B mode, a signal obtained by bit-compressing a standard CD-DA format digital signal by about 4 times is reproduced. Therefore, for example, when all of the recorded data are stereo audio compression data, reproduction can be performed for about four times as long (or for four channels), and even if the optical disc has a diameter of about 6 cm, it can be reproduced.
It is possible to record and reproduce for about a minute.

[0008]

By the way, in the optical disk capable of recording and reproducing as described above, if the recording characteristic of the recording film changes, the recording and reproducing are adversely affected. Therefore, when manufacturing the recordable / reproducible optical disc, it is necessary to manage the fluctuation of the reflectance of the recording film in the manufacturing process. Normally, the reflectance of the recording film is measured during the manufacturing, and The fluctuation of the recording characteristics is controlled by feeding back the measurement result of the reflectance to the film forming process at the time of manufacturing the recording film.

Here, in a recordable optical disc such as the CD-MO format, since pre-pits and wide grooves are formed in the pre-format, reflectance is provided in the program area formed by the pre-pits and wide grooves. There is no part that can be measured (area where there is no groove). Therefore, for example, even if the reflectance is measured in the area where the groove is present, the reflectance changes depending on the groove shape of the disk substrate.
The reflectance cannot be measured accurately. From such a thing,
In the above-mentioned CD-MO format optical disc, a mirror zone is provided in the outer peripheral portion, and the reflectance is measured in this mirror zone.

However, in recent years, there is also a recordable optical disc of a format having a few mirror zones on the outer peripheral portion of the disc and having a program area in which pre-pits and wide grooves are formed by pre-formatting. In the case of such an optical disc, it is difficult to measure the reflectance because there is almost no mirror zone in the outer peripheral portion, and the reflectance becomes unstable because the mirror zone is close to the edge of the disc. However, the reflectivity is different from that of the program area, and the reliability is low.

Therefore, the present invention has been proposed in view of the above-mentioned circumstances, and provides a program area in which there are few mirror zones in the outer peripheral portion and pre-pits and wide grooves are formed by pre-formatting. It is an object of the present invention to provide a recordable optical disc that can measure the reflectance effectively without any problem in terms of the format even if the recordable optical disc has the recordable format.

[0012]

The optical disk of the present invention comprises:
The present invention has been proposed to achieve the above-mentioned object, and in a recordable optical disc in which recording / reproduction of digital data is performed using at least a light beam from an optical head, the light beam focused on the disc. A reflection area larger than the beam spot diameter is provided at a predetermined position in the data recording area (program area).

Here, in the optical disc of the present invention,
The size of the reflection area is 3 μm to 10 μm when the beam spot diameter is approximately 1.6 μm.

Further, it is preferable that the position of the reflection area is a position excluding a sync signal recording portion recorded in the data recording area (program area).

Further, it is preferable that the above-mentioned reflection regions are provided at a plurality of places.

That is, the optical disk of the present invention is a recordable optical disk of a format having a few mirror zones in the outer peripheral portion and having a program area in which pre-pits and wide grooves are formed in the pre-format, and an optical head. Grooves exist for an extremely short period (about 3 μm to 10 μm) that does not affect tracking servo and focus servo by (optical pickup head), and so-called ATIP (Absolute Time In Pre-groove: or ADIP: Address In Pre-groove). It is characterized in that a non-use area (the above-mentioned reflection area) or a pseudo mirror area (the above-mentioned reflection area) in which an adjacent track and a groove are connected is provided so that the reflectance of the recording film can be measured in this reflection area. .. The length of the reflection area (reflectance measurement area) is 3 μm to 10 μm.
The length m is such that the servo signal and the ATIP signal (address) are hardly affected.

[0017]

According to the optical disk of the present invention, since the reflection area larger than the beam spot diameter of the light beam is provided at the predetermined position of the data recording area, this reflection area is used for measuring the reflectance of the recording film. You can Also, when the beam spot diameter is about 1.6 μm, the size of the reflection area is 3 μm.
If it is set to 10 μm, it does not affect the tracking servo, focus servo, ATIP, and the like. Further, the sync signal can be reproduced by setting the position of the reflection area to the position excluding the sync signal recording portion recorded in the data recording area. Furthermore, the reflectance can be measured more accurately by providing the reflective regions at a plurality of locations.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

The optical disk of the embodiment of the present invention is a magneto-optical disk capable of recording / reproducing digital data by using a light beam (laser beam) from an optical head (optical pickup head) and a magnetic head. Therefore, a reflection area M larger than the beam spot diameter of the light beam is provided at a predetermined position in the data recording area (program area).

Here, in the optical disc of the present embodiment, the size of the reflection area M is 3 μm to 10 μm when the beam spot diameter is approximately 1.6 μm. Further, the position of the reflection area M is a position excluding a later-described sync signal recording portion (sync) recorded in the data recording area (program area). Further, the reflection area M
Are provided at multiple locations.

That is, the optical disk of the present embodiment is a magneto-optical disk capable of recording and reproducing in a format having a few mirror zones in the outer peripheral portion and having a program area in which pre-pits and wide grooves are formed in the pre-format. Tracking servo and focus servo by the optical head, and the so-called ATIP (A
bsolute Time In Pre-groove: Or ADIP: Addres
s In Pre-groove), the area where the groove does not exist for a very short period (about 3 μm to 10 μm) (the reflection area M) or a pseudo mirror area where the adjacent track and the groove are connected (the reflection area). M) is provided so that the reflectance of the recording film can be measured in this reflection area M. The length of the reflection area (reflectance measurement area) M, 3 μm to 10 μm, is such a length that it hardly affects not only the servo signal but also the ATIP signal (address).

Therefore, when the optical disc of the present embodiment is reproduced, as shown in FIG. 1A, a portion (groove) where the voltage level I _g of the reproduction RF signal (sum signal) at the time of tracking on corresponds to the reflection area M is set. (Interrupted portion) R _M takes a value substantially the same as the voltage level I _o . At this time, as shown in FIG. 1B, the tracking error signal is zero (GN) in the portion TE _M corresponding to the reflection area M.
D level). From this, by detecting the portion R _M from the reproduction RF signal, the reflection area on the high disc can be found.

Further, the above-mentioned optical disc is the above-mentioned CD.
ATIP is adopted as the address recording method as in the MO format. In this method, the groove is wobbled in a radial direction in a sine wave shape, and the period of this sine waveform is FM-modulated to record an address. The frequency of this FM modulation is, for example, 22.05 kHz
Therefore, the tracking servo during recording / reproduction does not follow the wobbling of the groove. Also,
In this embodiment, the recording frequency of the EFM signal is about 200 kHz.
Since it is from z to 720 kHz, it is hardly affected by the above wobbling. According to the above ATIP, as described above, addresses and EFs are used in different frequency regions.
Since M signals are recorded, each signal can be recorded in the same space on the surface of the optical disc.

Furthermore, the optical disc has a linear velocity of 1.
It is set to 20 m / s-1.40 m / s. Therefore, the wobbling cycle is about 60μ on the surface of the optical disc.
m. Also, one bit of ATIP is about 200μ.
Since it is m, even if the groove is missing by, for example, about 10 μm, the above ATIP error hardly occurs. Also for the focus servo and the tracking servo, even if the groove is omitted by about 10 μm, there is no influence. This is because the servo characteristics are designed not to respond even if there is a gap of about 10 μm on the surface of the optical disk.

In the present embodiment, by utilizing the above-mentioned characteristics, an area (reflection area M) where there is no groove at a certain cycle (address cycle of 75 kHz or its multiplication) in a continuous groove or an adjacent track is used. A pseudo mirror zone (reflection area M) connecting the groove and the groove is provided, and the reflectance of the recording film can be measured in the reflection area M.

That is, according to this embodiment, the reflectance of the recording film of the optical disc 2 can be measured by providing the reflection region (mirror zone) M in the program area (data recording region) described later of the optical disc. There is. As a result, it becomes possible to measure the reflectance fluctuation in the manufacturing process and control the fluctuation of the recording characteristics, and the feedback of the reflectance measurement result to the film forming step becomes quick.

FIG. 2 shows a recording / reproducing apparatus for the optical disc 2 of this embodiment. It should be noted that a more detailed description of the optical disc 2 and the recording / reproducing apparatus thereof of this embodiment will be described later with reference to FIG. 3 and subsequent figures, and only an outline is shown in FIG.

In FIG. 2, the optical disc 2 is housed in a cartridge 31, and the recording / reproducing apparatus for the optical disc 2 includes a magnetic head 4 required for recording, an optical head 3 used for recording / reproducing, and an optical disc. And a spindle motor 1 for rotating 2. The magnetic head 4 of this embodiment is fixed to an arm 51 whose one end is rotatably supported, and the magnetic head 4 slides on the surface of the rotating optical disk 2.

Here, the signal read from the optical disk 2 by the optical head 3 is an audio signal compressed by a data compression / expansion circuit 41 which performs a data compression process as described later. This optical disc 2
The signal read from is, for example, a 1 Mbit D-RA.
An LSI of the data compression / expansion circuit 41, which is stacked in the M (dynamic RAM) 40 at a transfer rate of about 5 times.
(Large scale integrated circuit) demodulated.

Further, since audio data for about 3 seconds is stacked in the D-RAM 40 as described later, even if the optical head 3 causes a track jump, for example, the audio data in the D-RAM 40 remains. During this period, the audio signal taken out from the terminal 42 is not interrupted.

Next, the optical disc of this embodiment will be described with reference to FIGS. That is, FIG. 3 is a plan view of the optical disc of the present embodiment, and FIG. 4 is a schematic plan view showing a state where the optical disc is housed in a cartridge (or caddy). FIG. 5 shows the inner diameter dimension and outer diameter dimension of the data recording area of the optical disc of this embodiment.

First, an optical disk such as a magneto-optical disk has a diameter d at the center of the disk 2, as shown in FIG.
A hole of _H , a so-called center hole 38 is formed, and a spindle is inserted into the center hole 38,
The disk 2 is rotationally driven by being chucked. The disc 2 is housed in, for example, a cartridge (or disc caddy) 31 as shown in FIG. 4 to form a disc device 30, and the cartridge 31 is provided with, for example, a shutter plate 39 that can be opened and closed. Has been.

Again in the disk 2 of FIG. 3, the inner diameter dimension of the data recording area (program area) RA is d _I and the outer diameter dimension thereof is d _O. A lead-in area or TOC (table of contents) area is provided further inside the data recording area RA, and the inner diameter of this area is d.
_L. Further, a so-called rim portion is provided further outside the data recording area RA and between the disk outer diameter dimension d _D. The optical head OP (optical head 3) shown by the broken line in FIG. 3 shows a state of tracing the innermost circumference (inner diameter dimension d _L ) of the lead-in area.

Next, in FIG. 5, the horizontal axis represents the outer diameter dimension d _O of the data recording area RA, and the vertical axis represents the inner diameter dimension d _I of the data recording area RA. Curve L
₆₀ , L ₆₄ , L ₆₈ , L ₇₂ , and L ₇₆ are 60 minutes, 64 minutes, 68 minutes, 72 minutes, and 78 minutes of recording / reproducing time in the above-mentioned level B of the CD-I format and the stereo mode, respectively.
The relationship between the outer diameter dimension d _O and the inner diameter dimension d _I is shown. Other conditions of the recording format of the disc at this time are the standard CD format (CD-D
A format), the track pitch is 1.6 μm and the linear velocity is 1.2 m / s.

Here, the inner diameter dimension d of the data recording area RA
_{Although the} lower limit of _I is 28 mm, it is preferable to set the lower limit of 32 mm when using a disk having a flat surface on both sides, which is the same as a normal so-called CD. This is in consideration of the minimum size of the optical head that can be realized by the present technology and the size required for chucking (clamping) of the disk. That is, when the inner diameter dimension d _I is 32 mm, the inner diameter dimension d _L of the lead-in area is 30 mm.
However, since the diameter d _H of the center hole 38 needs to be at least 10 mm, the center hole 38
Is 10mm on one side between the inner circumference of the lead-in area and
Only the degree can be taken. This center hall 38
Since a width for chucking and clamping is required in the periphery of the optical head, the dimension of the optical head is 10 mm from the center to the outer wall, and the width for chucking and clamping is subtracted from the above 10 mm. However, this is close to the minimum size of the optical head that can be realized at present. From this point of view, it is necessary to set the lower limit of the inner diameter dimension d _L of the lead-in area to about 30 mm and the lower limit of the inner diameter dimension d _I of the data recording area RA to 32 mm.

Next, the inner diameter dimension d _I of the data recording area RA
The upper limit of 50 mm is set to 50 mm, which is the inner diameter dimension of the data recording area of a standard CD, in consideration of the fact that the recording capacity is reduced even if the dimension of the standard CD is exceeded and the advantage is small.

Therefore, the inner diameter dimension d of the data recording area RA
_I is, 32 mm or more, it is preferable to select within the following 50 mm.

Next, the outer diameter dimension d _O of the data recording area RA
May be determined in consideration of the required recording capacity according to the inner diameter dimension d _I. That is, according to the current data compression technology, the data compression rate that can satisfy the required sound quality, for example, the sound quality of the FM broadcasting level is limited to about 1/4 (or 4 times), and for example, the above-mentioned level. The B stereo mode is suitable. At this time, the relationship between the recording / reproducing time and the inner diameter and outer diameter of the data recording area is
Other conditions are the same as standard CD, and linear velocity is 1.2m.
/ S, the curves L _{60 to} L _{76 in} FIG. 5 are obtained. On the other hand, as a proper recording / reproducing time when used by the user side, it is a standard that one classical music symphony can be recorded, that is, the current 12c.
A recording / reproducing time of about 74 minutes, which is about the same as mCD, is desired. Here, the respective dimensions d _O and d _I for obtaining a recording / reproducing time of at least about 72 minutes to 76 minutes fall within the range of the halftone dot area in FIG. 5, and further data recording due to changes in recording conditions etc. Data recording area R in consideration of increase / decrease in capacity
When the inner diameter d _{I of A} is 32 mm, the above outer diameter d
_{When O} is selected to a value within the range of 60 mm to 62 mm (points P _{a to} P _{b in} FIG. 5) and the inner diameter dimension d _I of the data recording area RA is 50 mm, the outer diameter dimension d _O is 71 mm to 73 mm.
It is preferable to select a value within the range (points P _{c to} P _{d in} FIG. 5).

Here, a specific example of one preferable value is the inner diameter dimension d _I = 32 mm of the data recording area RA, and the outer diameter dimension d _O = 61 mm of the data recording area RA. , For example, center hole inner diameter dimension d _H = 10 mm, lead-in area inner diameter dimension d _L = 30 mm, disc outer diameter dimension d _D = 64 mm, and this disc is stored in a disc cartridge (caddy) 70 mm × 74 mm in length and width and supplied to the market. By doing so, it is possible to record / reproduce on / from the disc by using a recording / reproducing apparatus of a so-called pocket size which is very small.

In addition to this, it is conceivable that the inner diameter dimension d _{I of the} data recording area RA is 42 mm and the outer diameter dimension d _O of the data recording area RA is 67 mm, and other dimensions at this time are, for example, the lead-in area. The inner diameter dimension d _L = 40 mm and the disk outer diameter dimension d _D = 70 mm. It is also conceivable that the inner diameter dimension d _{I of the} data recording area RA is 50 mm and the outer diameter dimension d _O of the data recording area RA is 72 mm. Other dimensions at this time are, for example, the lead-in area inner diameter dimension d _L. = 46 mm The outer diameter of the disk d _D = 76 mm. In addition, it goes without saying that various combinations are possible within the range that satisfies the above-mentioned dimensional conditions.

Next, a specific example of a disc recording / reproducing apparatus in which the above-mentioned optical disc 2 is used will be described with reference to FIG. That is, FIG. 6 shows a schematic configuration of a disc recording / reproducing apparatus in which the above-mentioned optical disc according to an embodiment of the present invention is used.

In the disc recording / reproducing apparatus shown in FIG. 6, the magneto-optical disc 2 rotatably driven by the spindle motor 1 is used as a recording medium. By applying a modulation magnetic field according to recording data to the magneto-optical disk 2 by the magnetic head 4 while irradiating the optical head 3 with laser light, for example, data is recorded along the recording track of the magneto-optical disk 2. Recording (so-called magnetic field modulation recording) is performed, and the recording track of the magneto-optical disk 2 is traced with a laser beam by the optical head 3 to magneto-optically reproduce data.

The optical head 3 includes, for example, a laser light source such as a laser diode, a collimator lens, an objective lens,
It is composed of a polarization beam splitter, an optical component such as a cylindrical lens, and a photodetector divided into a predetermined arrangement, and is provided at a position facing the magnetic head 4 with the magneto-optical disk 2 in between. In the optical head 3, when recording data on the magneto-optical disk 2, the magnetic head 4 is driven by a head drive circuit 16 of a recording system, which will be described later, to apply a modulation magnetic field according to the recording data. Data is recorded by thermomagnetic recording by irradiating the target track of the magnetic disk 2. Further, the optical head 3 detects a focus error by, for example, the so-called astigmatism method by detecting the reflected light of the laser light applied to the target track, and also detects a tracking error by, for example, the so-called push-pull method, and When the data is reproduced from the magneto-optical disk 2, the reproduction signal is generated by detecting the difference in the polarization angle (Kerr rotation angle) of the laser light reflected from the target track.

The output of the optical head 3 is supplied to the RF circuit 5. The RF circuit 5 extracts the focus error signal and the tracking error signal from the output of the optical head 3 and supplies them to the servo control circuit 6, and also binarizes the reproduction signal to supply it to a reproduction system decoder 21 described later. ..

The servo control circuit 6 is composed of, for example, a focus servo control circuit, a tracking servo control circuit, a spindle motor servo control circuit, a sled servo control circuit, and the like. The focus servo control circuit controls the focus of the optical system of the optical head 3 so that the focus error signal becomes zero. Also,
The tracking servo control circuit controls the tracking of the optical system of the optical head 3 so that the tracking error signal becomes zero. Further, the spindle motor servo control circuit controls the spindle motor 1 so as to drive the magneto-optical disk 2 to rotate at a predetermined rotation speed (for example, a constant linear speed). The sled servo control circuit moves the optical head 3 and the magnetic head 4 to the target track position of the magneto-optical disk 2 designated by the system controller 7. The servo control circuit 6 performing such various control operations supplies the system controller 7 with information indicating the operating state of each part controlled by the servo control circuit 6.

Further, the system controller 7 is connected to a key input operation section 8 and a display section 9. The system controller 7 controls the recording system and the reproducing system in the operation mode designated by the operation input information from the key input operation unit 8. In addition, this system controller 7
Is recorded on the recording track traced by the optical head 3 and the magnetic head 4 based on address information in sector units reproduced from the recording track of the magneto-optical disk 2 by header time, sub-Q data, or the like. Manage the position and playback position. The system controller 7 further includes bit compression mode information in the ADPCM encoder 13, which will be described later, which is switched and selected by the key input operation unit 8 and bits in reproduction data obtained from the RF circuit 5 through a reproduction system, which will be described later. The bit compression mode is displayed on the display unit 9 based on the compression mode information, and the reproduction time is displayed on the display unit 9 based on the data compression rate in the bit compression mode and the reproduction position information on the recording track. Control.

This reproduction time display shows the sector unit address information (absolute time information) reproduced from the recording track of the magneto-optical disk 2 by the header time, sub-Q data, etc., and the data compression rate in the bit compression mode. By multiplying the reciprocal number (for example, 4 in the case of 1/4 compression), the actual time information is obtained and displayed on the display unit 9. Even at the time of recording, when absolute time information is recorded (pre-formatted) in advance on a recording track of a magneto-optical disk or the like, the pre-formatted absolute time information is read to determine the data compression rate. It is also possible to display the current position at the actual recording time by multiplying by the reciprocal.

Here, the recording system of this disc recording / reproducing apparatus includes an A / D converter 12 to which an analog audio signal A _IN is supplied from an input terminal 10 via a low-pass filter 11.

The A / D converter 12 quantizes the audio signal A _IN, and the digital audio data obtained from the A / D converter 12 is ADPCM (Adapted).
iveDifferential Pulse Code Modulation) Encoder 13 is supplied. This ADPCM encoder 13 is
The audio signal A _IN is quantized by the A / D converter 12 and the digital audio data having a predetermined transfer rate is subjected to data compression processing corresponding to various modes in the above-mentioned CD-I system. The operation mode is specified by. For example, in the B-level mode, compressed data (ADPCM audio data) having a sampling frequency of 37.8 kHz and 4 bits per sample is supplied to the memory 14. The data transfer rate in the B-level stereo mode is reduced to 18.75 sectors / second).

Here, in the specific example of FIG. 6, the sampling frequency of the A / D converter 12 is, for example, the standard C mentioned above.
4 which is the sampling frequency of D-DA format
The frequency is fixed to 4.1 kHz, and the ADPCM encoder 13 converts the sampling rate according to the compression mode (for example, from 44.1 kHz to 3 at level B).
It is assumed that the bit compression processing from 16 bits to 4 bits is performed after the conversion to 7.8 kHz). As another configuration example, the A / D converter 1
The sampling frequency of 2 may be controlled to be switched according to the compression mode. In this case, the cutoff frequency of the low-pass filter 11 may also be controlled according to the sampling frequency of the A / D converter 12 which is controlled to switch. Switch control. That is, the sampling frequency of the A / D converter 12 and the cutoff frequency of the low pass filter 11 may be simultaneously switched and controlled according to the compression mode.

Next, in the memory 14, writing and reading of data are controlled by the system controller 7 and supplied from the ADPCM encoder 13.
It is used as a buffer memory for temporarily storing DPCM audio data and continuously recording it on the disc as needed. That is, in the B level stereo mode, the compressed audio data supplied from the ADPCM encoder 13 has its data transfer rate reduced to 18.75 sectors / sec, and this compressed data is continuously stored in the memory 14. Will be written. As for this compressed data (ADPCM data), it is sufficient to record one sector for every four sectors as described above, but since recording every four sectors is practically impossible, it is possible to write data in consecutive sectors as described below. I try to keep a record. This recording is carried out in bursts at 75 sectors / second with a cluster consisting of a plurality of predetermined sectors (for example, 32 sectors) as a recording data unit through the pause period. That is, in the memory 14, ADPCM audio data in the B level stereo mode continuously written at a low transfer rate of 18.75 (= 75/4) sectors / second corresponding to the bit compression rate is recorded data. The data is read in bursts at the transfer rate of 75 sectors / sec. The overall data transfer rate of the read and recorded data, including the recording pause period, is as low as 18.75 sectors / sec described above, but within the time of the recording operation performed in bursts. The instantaneous data transfer rate in the above is the standard 75 sectors / sec. Therefore, when the disc rotation speed is the same as the standard CD-DA format (constant linear velocity), the CD-
Recording with the same recording density and storage pattern as in the DA format will be performed.

The ADPCM audio data, that is, the recording data, which is burst-read from the memory 14 at the transfer rate of 75 sectors / second is supplied to the encoder 15. Here, from the memory 14 to the encoder 15
In the data string supplied to the above, the unit of continuous recording in one recording is a cluster composed of a plurality of sectors (for example, 32 sectors) and several sectors for cluster connection arranged in the front and rear positions of the cluster. The sector for cluster connection is set longer than the interleave length in the encoder 15 so that the data of other clusters will not be affected even if interleaved. Details of this cluster unit recording will be described later with reference to FIG. 7.

The encoder 15 performs coding processing (parity addition and interleave processing) for error correction, EFM coding processing, etc. on the recording data supplied in bursts from the memory 14 as described above. The recording data encoded by the encoder 15 is supplied to the magnetic head drive circuit 16.

The magnetic head drive circuit 16 is connected to the magnetic head 4 and drives the magnetic head 4 so as to apply a modulation magnetic field according to the recording data to the magneto-optical disk 2.

Further, the system controller 7 performs the above-mentioned memory control on the memory 14, and the recording data burst-read from the memory 14 by the memory control is recorded on the recording track of the magneto-optical disk 2. The recording position is controlled so that recording is performed continuously. This recording position is controlled by the memory 14 described above.
By controlling the recording position of the recording data read out in a burst from the system controller 7 and supplying a control signal for designating the recording position on the recording track of the magneto-optical disk 2 to the servo control circuit 6. Done.

Next, the reproducing system in this disc recording / reproducing apparatus will be described. This reproducing system is for reproducing the record data continuously recorded on the recording track of the magneto-optical disk 2 by the recording system as described above, and the recording track of the magneto-optical disk 2 by the optical head 3. Is provided with a decoder 21 to which the reproduction output obtained by tracing with the laser light is binarized by the RF circuit 5 and supplied.

The decoder 21 corresponds to the encoder 15 in the recording system, and is the R
The reproduction output binarized by the F circuit 5 is subjected to the above-described decoding processing for error correction, EFM decoding processing, and the like, and the A level of the B-level stereo mode described above.
The DPCM audio data is reproduced at a transfer rate of 75 sectors / second which is faster than the normal transfer rate in the B level stereo mode. The reproduced data obtained by the decoder 21 is supplied to the memory 22.

In the memory 22, writing and reading of data are controlled by the system controller 7, and reproduced data supplied from the decoder 21 at a transfer rate of 75 sectors / sec burst at the transfer rate of 75 sectors / sec. Will be written. In addition, this memory 22
The read data written in bursts at the transfer rate of 75 sectors / sec is continuously read at the regular transfer rate of 18.75 sectors / sec in the B-level stereo mode.

The system controller 7 writes the reproduction data into the memory 22 at a transfer rate of 75 sectors / second, and continuously writes the reproduction data from the memory 22 at a transfer rate of 18.75 sectors / second. Memory control such as reading is performed.

Further, the system controller 7 performs the above-mentioned memory control on the memory 22, and the reproduction data burst-written into the memory 22 by the memory control is recorded from the recording track of the magneto-optical disk 2. The playback position is controlled so that playback is performed continuously. This playback position is controlled by the memory 22.
By controlling the reproduction position on the recording track of the magneto-optical disk 2 of the reproduction data written in a burst manner to the system controller 7 and supplying a control signal designating the reproduction position to the servo control circuit 6. Done.

The B-level stereo mode ADPCM audio data obtained as reproduction data continuously read from the memory 22 at a transfer rate of 18.75 sectors / second is supplied to the ADPCM decoder 23.

The ADPCM decoder 23 corresponds to the ADPCM decoder 13 of the recording system, and the operation mode is designated by the system controller 7.
In this disc recording / reproducing apparatus, ADPCM audio data in B level stereo mode is expanded four times to reproduce digital audio data in CD-DA mode. The ADPCM decoder 23 supplies the digital audio data to the D / A converter 24.

The D / A converter 24 is the ADPCM.
The digital audio data supplied from the decoder 23 is converted into an analog signal, and the analog audio signal A _{OUT is} output.
To form. The analog audio signal A _OUT obtained by the D / A converter 24 is a low-pass filter 25.
Is output from the output terminal 26 via.

The reproducing system of the disk recording / reproducing apparatus of this specific example also has a digital output function. The ADPCM decoder 23 outputs digital audio data as a digital audio signal D _OUT via the digital output encoder 27. Terminal 28
Will be output from.

The recording / reproducing operation of the recording / reproducing apparatus as described above will be described in more detail. First, the recording data (data read from the memory 14) is clustered for every fixed number (for example, 32) of sectors (or blocks), and some sectors for cluster connection are provided between these clusters. It is arranged. Specifically, as shown in FIG. 7, the cluster Cn is composed of 32 sectors (blocks) B0 to B31, and five connection sectors (Linking S) are provided between these clusters Cn.
ector) L1 to L5 are arranged and connected to the adjacent cluster. Here, one cluster, for example, the kth cluster C
_{When k} is recorded, not only the 32 sectors B0 to B31 of this cluster C _k but also 3 sectors each for the front and rear, that is, 3 sectors on the side of the cluster C _k-1 L3 to L5 ( A total of 38 sectors including the run-in block) and the three sectors L1 to L3 (run-out block) on the side of the cluster C _{k + 1} are recorded as a unit. At this time, the encoder 15 interleaves the recorded data for 38 sectors to rearrange the distances of a maximum of 108 frames (corresponding to about 1.1 sectors). For data in C _k , run-in block above
It is well within the range from L3 to L5 to the run-out blocks L1 to L3 and does not affect other clusters C _k-1 and C _{k + 1} . In addition, linking sector L1 ~
Dummy data such as 0 is arranged in L5, and the adverse effect on the original data due to the interleave processing can be avoided. When recording the next cluster C _{k + 1} , five linking sectors with the cluster C _k are recorded.
Since three sectors L3 to L5 of L1 to L5 are used as a run-in block, the sector L3 is recorded redundantly, but there is no problem. In addition, the L3 of either the line-in block or the run-out block was removed 37
Recording may be performed in units of sectors.

By performing such recording in cluster units, it is not necessary to consider mutual interference due to interleaving with other clusters, and data processing is greatly simplified. Also, if recording data could not be recorded normally during recording due to defocusing, tracking deviation, or other malfunctions, re-recording could be performed in cluster units above, and if effective data reading could not be performed during playback. Re-reading can be done in cluster units.

By the way, one sector (block) has 23
It consists of 52 bytes, 12 bytes for synchronization, 4 bytes for header, and data D0001 to D2336 from the beginning 2
336 bytes are arranged in this order. This sector structure (block structure) is represented as two-dimensional array data as shown in FIG. 8, and the 12 bytes for synchronization are the first 1
The byte is 00H (H indicates a hexadecimal number), 10 bytes of FFH follow, and the last 1 byte is 00H. The next 4-byte header consists of one byte each for minutes, seconds, and the address portion of the block, followed by one byte for mode information. This mode information is mainly for indicating the mode of the CD-ROM, and the sector structure shown in FIGS. 7 and 8 corresponds to the mode 2 of the CD-ROM format. CD-I is a standard using this mode 2, and the contents of D0001 to D0008 of the above data are defined as shown in FIG.

FIG. 10 shows Form 1 and Form 2 of the CD-I standard. The 12 bytes for synchronization and the 4 bytes for the header correspond to the mode 2 of the CD-ROM (see FIGS. 7 and 8). Are the same. 8 for next subheader
The byte is specified as shown in FIG. 9 above, and the data D
0001 and D0005 are file numbers, data D0002 and D0006 are channel numbers, data D0003 and D0007 are submode information, and data D0004 and D0008 are data type information. The data D0001 to D0004 and D0005 to D0008 have the same content written twice. 232 below
In Form 1 of FIG. 10A, the 8 bytes consist of 2048 bytes for user data, 4 bytes for error detection, 172 bytes for P parity, and 104 bytes for Q parity. This form 1 is used for recording character information, binary data, highly compressed video data and the like. In form 2 of FIG. 10B, 2324 bytes below the subheader are user data, and the remaining 4 bytes are reserved data. This form 2 is used for recording compressed audio data and video data. In the case of compressed audio data, 18 groups (2304 bytes) of 128-byte sound groups are arranged in 2324 bytes of user data, and the remaining 20 groups.
The bytes are free space.

By the way, when data having such a sector structure is recorded on the disk, encoding processing including parity addition and interleaving processing is performed by the encoder 15, and EFM (8-14 modulation) processing is performed. Made, fig 1
Recording is performed in the recording format as shown in 1.

In FIG. 11, one block (one sector) consists of 98 frames from the first frame to the 98th frame, and one frame is a channel clock cycle T.
588 times (588T) of the frame synchronization pattern part of 24T (+ 3T connection bit) in one frame, 14T
A (+ connection bit 3T) subcode portion and a 544T data (audio data and parity data) portion are provided. The data portion of 544T is 12 bytes (12 symbols) of audio data, 4 bytes of parity data, 12 bytes of audio data, and 4 bytes of parity data that are so-called EFM modulated. Is 24 bytes (ie 1 word of audio sample data is 16
Since it is a bit, it is 12 words). The sub-code portion is EFM-modulated 8-bit sub-code data, and is divided into blocks of 98 frames, and each bit constitutes eight sub-code channels P to W. However, the subcode portions of the first and second frames have block synchronization patterns S _{0 and} S ₁ out of the EFM modulation rule (out-of-rule), and the subcode channels P to W are from the third frame to the third frame. There are 96 bits each for up to 98 frames.

Although the above audio data is interleaved and recorded, it is deinterleaved at the time of reproduction to obtain audio data having a data array in the order of time. Instead of this audio data,
For example, CD-I data and the like as shown in FIGS. 8 and 10 can be recorded.

By the way, in the disc recording / reproducing apparatus of FIG. 6, the digital data obtained from the A / D converter 12 is, as shown in FIG. 12, the same data as the CD-DA format, that is, the sampling frequency 44. The audio PCM data has a frequency of 1 kHz, a quantization bit number of 16 bits, and a data transfer rate of 75 sectors / second. When this is sent to the ADPCM encoder 13 and bit-compressed to, for example, the above-mentioned B-level stereo mode, it is first rate-converted to a sampling frequency of 37.8 kHz, and the number of quantization bits is compressed to 4 bits. , And is output as ADPCM audio data with a data transfer rate of 1/4, which is 18.75 sectors / sec. The BPCM stereo mode ADPCM audio data continuously output from the ADPCM encoder 13 at a transfer rate of 18.75 sectors / second is supplied to the memory 14.

The system controller 7 sets the write pointer (W) of the memory 14 to 1 as shown in FIG.
By continuously incrementing at a transfer rate of 8.75 sectors / sec, ADPCM audio data is continuously written to the memory 14 at a transfer rate of 18.75 sectors / sec and stored in the memory 14. A above
When the data amount of the DPCM audio data exceeds a predetermined amount K, the read pointer (R) of the memory 14 is burst-incremented at a transfer rate of 75 sectors / second to record the ADPCM audio data from the memory 14. Then, memory control is performed so that a predetermined amount K is read out in burst at the transfer rate of 75 sectors / sec. However, the predetermined amount is based on the data amount of one cluster.

That is, in the recording system of the disc recording / reproducing apparatus shown in FIG. 6, the memory control by the system controller 7 continuously outputs from the ADPCM encoder 13 at a transfer rate of, for example, 18.75 sectors / second. The ADPCM audio data to be written is written in the memory 14 at the transfer rate of 18.75 sectors / second, and the AD stored in the memory 14 is stored.
When the data amount of the PCM audio data becomes a predetermined amount K or more, the ADPCM audio data is read from the memory 14 as recording data by a predetermined amount K at a transfer rate of 75 sectors / second in a burst manner. It is possible to continuously write the input data in the memory 14 while always securing a data writing area of a predetermined amount or more therein. Here, the recording data read out in burst from the memory 14 is continuously recorded on the recording track of the magneto-optical disk 2 by controlling the recording position on the recording track of the magneto-optical disk 2 by the system controller 7. It is possible to record in the state to do. Moreover, as described above, since the memory 14 always has a vacant area of a predetermined amount or more, the system controller 7 detects that a track jump or the like has occurred due to disturbance or the like, and records on the magneto-optical disk 2. Even when the operation is interrupted, the input data can be continuously written in the empty area of the predetermined amount or more, and the recovery processing operation can be performed during that time, and the data is input in real time on the recording track of the magneto-optical disk 2. Input data can be recorded in a continuous state.

On the magneto-optical disk 2, header time data corresponding to the physical address of the sector is added to the ADPCM audio data for each sector and recorded. Further, the inventory data indicating the recording area and the recording mode is recorded in the inventory area (lead-in area, TOC area).

Next, in the reproducing system in the disc recording / reproducing apparatus of FIG.
As shown in, the write pointer (W) of the memory 22 is incremented at a transfer rate of 75 sectors / second, the reproduction data is written to the memory 22 at a transfer rate of 75 sectors / second, and The read pointer (R) is continuously incremented at a transfer rate of 18.75 sectors / sec, and the reproduction data is continuously read from the memory 22 at a transfer rate of 18.75 sectors / sec. (W) is the above read pointer
When it catches up with (R), writing is stopped and the above memory 22
Memory control is performed by incrementing the write pointer (W) of the memory 22 in burst at a transfer rate of 75 sectors / second so that writing is performed when the data amount of the reproduction data stored in the memory becomes a predetermined amount L or less. I do.

Therefore, in the reproducing system of such a disc recording / reproducing apparatus, the BPCM stereo mode ADPCM audio data reproduced from the recording track of the magneto-optical disc 2 is controlled by the memory control by the system controller 7. The ADPCM audio data is written in the memory 22 in bursts at a transfer rate of 75 sectors / second, and the ADPCM audio data is continuously read from the memory 14 as reproduction data at a transfer rate of 18.75 sectors / second. It is possible to continuously read the reproduced data from the memory 22 while always securing a predetermined amount of data L or more in the memory 22. The reproduction data read out in burst from the magneto-optical disk 2 is continuously reproduced from the recording track of the magneto-optical disk 2 by controlling the reproduction position on the recording track of the magneto-optical disk 2 by the system controller 7. It can be played in the state of being. Moreover, as described above, since the memory 22 always secures a predetermined amount of data L or more, the system controller 7 detects that a track jump or the like has occurred due to a disturbance or the like, and thus the magneto-optical disk 2 is processed. Even when the reproduction operation is interrupted, the reproduction data stored in the memory 22 can be read and the output of the analog audio signal can be continued, and the recovery processing operation can be performed during that time.

Here, in this disc recording / reproducing apparatus,
Although the recording / reproducing of the ADPCM audio data of the B level stereo mode has been described, the recording / reproducing of the ADPCM audio data of the other mode in the other CD-I system can be similarly performed.

[0079]

In the optical disk of the present invention, a reflection area larger than the beam spot diameter of the light beam focused on the disk is provided at a predetermined position of the data recording area, so that the reflection area is recorded. Therefore, even if the optical disc is a recordable optical disc of a format having a few mirror zones in the outer peripheral portion and having a program area in which pre-pits and wide grooves are formed in the pre-format, Therefore, it becomes possible to effectively measure the reflectance without any problem in the format.

The size of the reflection area is 3 μm to 10 μm.
By setting m, the tracking servo, focus servo, ATIP, and the like can be prevented from being affected, and the reflectance can be measured more accurately by providing the reflection regions at a plurality of locations.

[Brief description of drawings]

FIG. 1 is a diagram showing an RF signal and a tracking error signal when reproducing the optical disc of the present embodiment.

FIG. 2 is a diagram showing a schematic configuration of a recording / reproducing apparatus for the optical disc of the present embodiment.

FIG. 3 is a plan view of an optical disc.

FIG. 4 is a schematic plan view showing a state in which an optical disc is stored in a cartridge.

FIG. 5 is a graph showing a relationship between an inner diameter dimension and an outer diameter dimension of a data recording area of an optical disc.

FIG. 6 is a block diagram showing a configuration example of a disc recording / reproducing apparatus as one embodiment of the present invention.

FIG. 7 is a diagram showing a format of a cluster structure which is a recording unit.

FIG. 8 is a diagram showing an example of a data structure of one sector (one block).

FIG. 9 is a diagram showing the contents of a subheader.

FIG. 10 is a diagram showing a data structure in a so-called CD-I sector.

FIG. 11 is a diagram showing formats of frames and blocks (sectors) in the so-called CD standard.

FIG. 12 is a diagram showing a data format used in the disc recording / reproducing apparatus.

FIG. 13 is a diagram showing a memory-controlled memory state in the recording system of the disc recording / reproducing apparatus.

FIG. 14 is a diagram showing a memory-controlled memory state in a reproducing system of the disc recording / reproducing apparatus.

[Explanation of symbols]

 2 ... Optical disk 3 ... Optical head 4 ... Magnetic head 6 ... Servo control circuit 7 ... System controller 31 ... Disk cartridge 40 ... ..D-RAM 41 ..... Data compression / decompression circuit RA ..... Data recording area

Claims (4)

[Claims] 1. A recordable optical disc in which digital data is recorded / reproduced by using a light beam from at least an optical head, and a reflection area larger than a beam spot diameter of the light beam focused on the disc. An optical disc, wherein the optical disc is provided at a predetermined position in a data recording area. 2. The size of the reflection area is 3 μm to 10 μm.
The optical disc according to claim 1, wherein the optical disc is m. 3. The optical disc according to claim 1, wherein the position of the reflection area is a position excluding a sync signal recording portion recorded in the data recording area. 4. The optical disc according to claim 1, wherein the reflection area is provided at a plurality of locations.