JPH08138249A - Master disk recorder, optical disk and optical disk reproducing device - Google Patents

Abstract

PURPOSE: To enhance retrieval accuracy and to shorten the retrieval time to a target position. CONSTITUTION: The falling phase (r) of the square wave SMc of a sector mark SM is subjected to phase modulation according to information on disk diameters. This pseudo sector mark signal SM' subjected to the phase modulation is substd. with the original square wave SMc. The sector mark signal SMm after the substitution is recorded in a master disk by using a recorder. A replica optical disk is produced from this master disk. The sector mark signal is read when a focus servo is clocked at the time of reproducing the disk. In which track the sector mark signal exists is known by a difference between the integrated value of the section ab of the square wave SMc subjected to the phase modulation and the integrated value of the section bc. The assigned position is retrieved by utilizing the difference in the detected output value corresponding to this phase difference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk capable of recording / reproducing data such as a magneto-optical disk, a master disk recording apparatus for manufacturing the same, and an optical disk reproducing apparatus.

[0002]

2. Description of the Related Art An optical disk such as a magneto-optical disk capable of recording and reproducing data is divided into an inner recording area (channel 1) and an outer recording area (channel 2) as shown in FIG. 8A. One track formed in the recording area is composed of a plurality of sectors, for example 42 sectors. 1
The sectors are roughly classified into preformatted address portions (address areas) ADD and recording data write areas (data recording portions MO) as shown in FIG. 8B.

In the address portion ADD, as shown in FIG. 1B, address data of the same content is repeatedly formed three times following the sector marker signal SM. This address data is VF
O data, address marker AM, and identification data ID
Composed of. The sector mark signal SM is a marker necessary for detecting the head position of the sector, and it is also used as a reference pulse for a detection window for detecting the address marker AM.

VFO (variable frequency osillator)
Is a signal of a single frequency used for pulling in the operation of the PLL oscillator for clock generation in order to generate a reference signal (reference clock). Postamble data PA is recorded following the address data.

All of these address data are pre-formatted data and are formed by pits. There is a data recording unit MO following the address unit ADD, and a test area is provided at the beginning of this data recording unit MO. An ALPC test unit is provided in the test area for controlling the power level of the laser diode, and VFO data is recorded subsequently to the ALPC test unit.

A buffer area BA is provided at the end of the data recording section MO to clarify the boundary with the address section ADD. The number of sectors and the number of bytes constituting one sector shown in the figure are merely examples. The buffer area BA may record a specific single frequency even as a non-recording portion.

In an optical disk recording / reproducing apparatus using an optical disk capable of recording / reproducing data as described above, when a specific sector is designated at the time of starting an operation such as a reproduction mode, the optical pickup system is first used. It is necessary to detect the stop position (current position) of the optical block constituting the optical disk on the optical disc.

Conventionally, a potentiometer or the like is used as the position detecting means of the optical block. FIG. 9 is an example thereof, and the optical block 14 is arranged so as to face the optical disk 12. The optical block 14 is configured to be movable in the radial direction of the disc by a guide 16 or the like.

A potentiometer 18 is provided in association with the optical block 14 to detect the moving position of the optical block 14. The position information is supplied to the system control unit 20 having the CPU configuration, and the position information on the optical disk 12 is detected.

[0010]

SUMMARY OF THE INVENTION Potentiometer 18
When the position of the optical block 14 is detected by using, even if neither the focus servo of the optical block 14 nor the spindle motor servo that rotationally drives the optical disk 12 is locked, the tracking servo is locked. Even if it is not necessary, the optical block 14 can be moved to the designated approximate position, so that the access speed is increased.

However, when the potentiometer 18 is used, the position detection accuracy is not so high, and therefore the optical block 14 can be moved only to the roughly designated position. Therefore, in the case of the optical disc 12 having a very narrow track pitch, the search accuracy is very poor. When the normal optical disk 12 is used, there is an error of about ± 500 tracks. The same detection error occurs when the optical disk 12 is eccentric.

On the other hand, a system is being developed in which the optical block 14 is moved to a designated position after reading the data of the address portion ADD as shown in FIG. The position search accuracy is very high because the specified position is searched from the address data. Potentiometer 18
Becomes unnecessary.

However, this method is premised on that the address data can be read without error. For that purpose, both the focus servo, the spindle servo, and the tracking servo must be locked. Therefore, access is slower than using potentiometer 18.

In either case, whether the potentiometer 18 is used or the specified position is searched by referring to the address data, after confirming the current position of the optical block 14, the track traversed by the optical block 14 is detected. The number is counted and moved to the designated address (target position). Therefore, the target error becomes large when the optical disk 12 is eccentric,
Access time will be delayed.

In view of the above, the present invention has solved the above-mentioned conventional problems and has made it possible to improve the search accuracy and shorten the search time to the target position.

[0016]

In order to solve the above-mentioned problems, an optical disk according to claim 1 is configured such that one sector is composed of an address part and a data recording part each of which is pre-formatted, and the address part is formed. Has a sector mark signal for identifying a sector, and the sector mark signal is preformatted on the disc in a state of being modulated based on the disc diameter information.

According to another aspect of the master disk recording apparatus of the present invention, a specific rectangular wave of the sector mark signal is modulated based on the disk diameter information, and the sector mark signal having this modulated rectangular wave is transferred to the master disk. The feature is that pre-formatting is performed.

In the optical disk reproducing apparatus described in claim 6, an optical disk in which a sector mark signal modulated based on disk diameter information is pre-formatted as data of an address portion is used, and when reproducing this optical disk, an operation mode is set. At the time of start-up, the sector mark signal is detected, and the current position of the optical block constituting the optical pickup system on the optical disc is discriminated from the detected phase information.

[0019]

FIG. 2 shows the recording state of the sector mark signal SMm on the master disk. Conventional sector mark signal SM
2A, the falling phase r of the rectangular wave SMc existing in the middle is fixed as shown in FIG. 2A.

In the present invention, this falling phase r is phase-modulated as shown in FIGS. The phase-modulated pseudo sector mark signal SM 'is replaced with the original rectangular wave SMc. The sector mark signal SMm (FIG. 2G, H, I) after replacement is recorded on the master disk 32 using the recording device 30 of FIG. The replica optical disk 12 is manufactured from the master disk 32.

When reproducing a disc, the reproducing circuit 50 shown in FIG.
To use. Depending on the difference between the integrated value of the section ab of the phase-modulated rectangular wave SMc and the integrated value of the section bc, the optical block 14
It is possible to know on which track of the optical disk 12 is located. The specified position is searched by utilizing the difference in the detected output value corresponding to this phase difference. Sector mark signal SMm
Is different for each track group (one track group is, for example, 50 to 100 tracks), so that the position search can be performed with high accuracy.

Since the sector mark signal SMc can be read as long as the focus servo is locked, the optical block 14 can be moved to a designated position before the spindle servo and the tracking servo are locked, and the access time is correspondingly increased. Can be shortened. The access time is almost the same as when the potentiometer 18 is used.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a case where an example of the present invention is applied to an optical disk recording / reproducing apparatus using the MO disk described above will be described in detail with reference to the drawings.

For convenience of explanation, the principle of the present invention will be described with reference to FIG. The conventional sector mark signal SM is fixed to the pattern as shown in FIG. 7A. In the figure, T indicates a bit period.

In the present invention, attention is paid to the rectangular wave SMc existing in the middle of the sector mark signal SM thus patterned, and the falling phase r of this rectangular wave SMc is shown in FIGS. 7B and 7C according to the disc diameter information. The phase is modulated like. FIG. 9B shows an example of phase modulation at the innermost circumference, and FIG.
Is an example of phase modulation at the outermost circumference.

The rectangular wave SMc may have a slightly modified rectangular wave configuration as shown in D or E of the figure, and may be subjected to phase modulation. For the phase modulation example shown in FIGS. 2B and 2C,
The phase modulation examples of D and E in the same figure are more convenient than the former because the DC level does not change even when phase modulation is performed. However, in the following description, the former case is shown.

Now, how the phase of the rectangular wave SMc is phase-modulated using the disc diameter information will be described with reference to the master disc recording device 30 of FIG. 1 and the waveform diagram of FIG.

Since the data of the address portion ADD is pre-formatted on the optical disc, the sector mark signal SM to be recorded on the disc at the stage of producing a master disc for producing this optical disc.
Will be phase-modulated according to the disc diameter information.
Therefore, the format signal generating means 36 for generating various data signals forming the address portion ADD as shown in FIG. 8B is provided. This format generation means 36
Is a ROM, in which the synchronization signal generating means 34
Clock CK and sync signal SYNC are respectively supplied,
The format signal is read in synchronization with these.

Of the signals read from the format signal generating means 36, focusing on the sector mark signal SM,
The sector mark signal SM is a fixed pattern signal as shown in FIGS. 7A and 2A. This is supplied to the pseudo sector mark signal generating means 38 to generate a pseudo sector mark signal (rectangular wave signal) SM 'corresponding to the rectangular wave SMc as shown in FIG. 2B.

The pseudo sector mark signal SM 'is the synchronization signal SY.
It is supplied to the phase modulation means 40 together with the NC and the following processing is performed. From the pseudo sector mark signal SM 'to FIG.
As in C, a sawtooth wave signal ST corresponding to the length T of the rectangular wave SMc is formed with reference to the rising edge of the pseudo sector mark signal SM '.

On the other hand, the synchronization signal SYNC is used as disk diameter information. This is because the synchronization signal SYNC is position information in the circumferential direction of the disk, and the sum of these is the disk diameter information. The sync signal SYNC may be a signal associated with the track. Such disc diameter information is used as the reference level REF (FIG. 2C).
(Dashed line shown). In this example, the reference level REF increases as the disc diameter increases.

When the sawtooth wave signals ST are compared with reference to the reference level REF, which varies depending on the disk diameter, pseudo sector mark signals SM 'having different duties are obtained as shown in FIGS. 2D, 2E and 2F. That is, the pseudo sector mark signal S phase-modulated by the disk diameter
M'is obtained.

FIG. 6D shows a phase-modulated pseudo sector mark signal S when the innermost disk diameter in the data area is used.
M ', and E in the same figure shows the phase-modulated pseudo sector mark signal S when the disk diameter is the middle part of the data area.
M'and F in the same figure are phase-modulated pseudo sector mark signals SM 'for the outermost disk diameter in the data area. In this example, as shown in FIG. 4A, the phase is modulated so that the duty is 30% at the innermost circumference, 50% at the middle portion, and 70% at the outermost circumference.

In the case of an optical disc in which a guard area (non-recording area) is provided in the middle of the data area, as shown in FIG. 4B, the inner side and the outer side of the guard area are opposite as shown in the figure. Phase modulation can be performed. With such phase modulation, the phase modulation sensitivity is doubled, so
The reproduction detection sensitivity of the sector mark signal is improved accordingly.

Further, in this example, as shown in FIG. 3, a lead-in area is provided outside the innermost peripheral side of the optical disk 12, and a lead-out area is provided further outside thereof on the outermost peripheral side. The sector information is also pre-formatted in these areas. Therefore, FIG.
As in A, the lead-in area is subjected to 30% phase modulation and the lead-out area is subjected to 70% phase modulation to record the sector mark signal.

Phase-modulated pseudo sector mark signal S
M'is supplied to the gate circuit 42 and the gate pulse GSM obtained by the format signal generating means 36 (FIG. 2J).
Thus, the gate processing of the sector mark signal SM and the pseudo sector mark signal SM 'is performed. Gate pulse GS
M is selected to have a pulse width including at least the length T of one cycle of the rectangular wave SMc. Therefore, the sector mark signal SM is gated in the section p as shown in FIG.
The pseudo sector mark signal SM 'is gated. As a result, the sector mark signal SMm obtained from the gate circuit 42 becomes a sector mark signal phase-modulated by the disc diameter information as shown in FIGS. 2G, 2H and 2I.

The sector mark signal SMm is supplied to the optical block 46 via the laser driver 44 and recorded as pit information on the master disk 32. A large number of replicas (optical disks 12) are manufactured using this master disk 32.

The sector mark signal SMm thus preformatted is detected by the reproducing circuit 50 shown in FIG. When the focus servo is locked in the reproduction mode, the data in the address section ADD can be read, and therefore the phase-modulated sector mark signal SMm as shown in FIG. 2 is obtained as the output of the photodiode for detecting the laser return light. To be The sector mark signal SMm obtained at the terminal 52 is supplied to the detection circuit 54 to detect the sector mark signal SMm, and the gate pulse generation circuit 56 generates a gate pulse corresponding to the section including the rectangular wave SMc.

The gate pulse is supplied to the integrator 58 and the phase-modulated rectangular wave SMc is integrated. Then, as shown in FIG. 6A, a difference Vo (= Vb−Va) between the integrated value Va of the section a and the integrated value Vb of the section b is obtained. The differential output Vo is converted into digital data by the A / D converter 60 and supplied to the system controller 20.

Here, since the differential output Vo has a value corresponding to the duty of the rectangular wave SMc that has been phase-modulated, the position of the optical block 14 in a large space can be known from the differential output Vo. Therefore, when the position to move the optical block 14 is designated, the difference output Vo is monitored, and the control unit 20 gives a drive signal to the spindle motor until the difference output Vo corresponding to the designated position is detected.

When the phase of the rectangular wave SMc is modulated by the disc diameter information, it is possible to perform the phase modulation for each track, but if this is done, the sector mark signal reproduction circuit 50 detects it in units of one track unless the detection accuracy is very high. become unable. Therefore, in this example, a plurality of tracks are set as one group (for example, 50 to 100 tracks are set as one group) and the phase modulation is applied. Therefore, the duty of the sector marker signals formed on the tracks in the same group is the same.

The sector marker signal SMm is also used to detect the designated position.
Done by This is because the sector marker signal SMm itself has the rough track address information. The fine adjustment of the designated position may be performed with the original address data recorded in each sector. Even in this case, since the resolution is at least in units of one group, the detection accuracy is much higher than that when a potentiometer or the like is used.

Since the focus servo only needs to be locked to detect the sector mark signal SMm, the optical block 14 can be moved before the rotation speed of the optical disk 12 locked by the spindle servo becomes constant. Then, the sector mark signal SM input to the reproducing circuit 50
In the case of m, the obtained cycle is different before and after the speed is locked, as shown in FIG. However, unlike a: b and a ': b', the ratio of the sections does not change, so position search can be performed without being affected by the disk speed.

In FIG. 5, the detection of the differential output Vo by the integrator 58 can be obtained by integrating through the sections a and b in addition to the example described above, and a digital pulse instead of the integrator is used. When a measuring instrument is used, the difference output Vo can be obtained by measuring any two of the sections a, b, and c and obtaining the difference between them.

[0045]

As described above, according to the present invention, the sector mark signal is modulated based on the disc diameter information.

According to this, since the potentiometer is not used, the search error up to the designated position becomes very small. Since the potentiometer is not required, the construction of the optical block system becomes simple. Since only the sector mark signal is used, the search can be started only by locking the focus servo, and there is no need to wait until the spindle servo or tracking servo locks. Therefore, the access time can be shortened accordingly. Since the reading of the sector mark signal is not affected by the eccentricity of the disc, it has a feature that a highly accurate search can be performed even if the disc is eccentric.

If sector mark signals are recorded in both the lead-in area and the lead-out area, the absolute dead position of the optical block will not be lost during the search, so that the response dead zone can be eliminated. This is because when the potentiometer is used, the absolute position of the optical block may be lost due to the error of about ± 500 tracks.

Since the method of moving the optical block to the designated position by detecting the number of tracks after reading the address data is not a method, the target error becomes small and the access time can be shortened accordingly.

Therefore, the present invention is extremely suitable for application to a recording device and a reproducing device thereof, including a master disc for an optical disc in which the address portion is pre-formatted and obtained as a light intensity signal as described above.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of a master disk recording device to which the present invention is applied.

FIG. 2 is a waveform diagram for explaining the operation.

FIG. 3 is an explanatory diagram of an optical disc.

FIG. 4 is an explanatory diagram of phase modulation for a sector mark signal.

FIG. 5 is a system diagram showing an example of a sector mark signal reproducing circuit.

FIG. 6 is a diagram showing a relationship between a reproduction speed and a rectangular wave SMc.

FIG. 7 is an explanatory diagram of phase modulation of a sector mark signal.

FIG. 8 is an explanatory diagram of a recording format of a disc.

FIG. 9 is a system diagram of a conventional optical block control circuit.

[Explanation of symbols]

 36 Format Signal Generating Means 38 Pseudo Sector Mark Signal Generating Means 40 Phase Modulating Means 14, 46 Optical Block 12 Optical Disc 32 Master Disc 58 Integrator

Claims (6)

[Claims] 1. A sector is composed of a preformatted address portion and a data recording portion, and a sector mark signal for identifying the sector is provided in the address portion, and the sector mark signal is a disc diameter information. An optical disc which is pre-formatted on the disc in a state of being modulated according to the above. 2. The optical disc according to claim 1, wherein the sector mark signal is recorded in each of the lead-in area and the lead-out area. 3. The optical disc according to claim 1, wherein the modulation based on the disc diameter information is phase modulation. 4. A master disk, wherein a specific rectangular wave of the sector mark signal is modulated based on disk diameter information, and the sector mark signal having this modulated rectangular wave is pre-formatted on a master disk. Recording device. 5. The master disk recording apparatus according to claim 4, wherein the rectangular wave is phase-modulated based on disk diameter information. 6. An optical disk reproducing apparatus using an optical disk in which a sector mark signal modulated based on disk diameter information is pre-formatted as data of an address part, wherein the sector mark signal is detected when an operation mode is started up. The disc reproducing apparatus is adapted to determine the current position on the optical disc of the optical block constituting the optical pickup system from the detected phase information.