JPH08124180A - System for seeking recording/reproducing position on optical disk - Google Patents

Abstract

PURPOSE: To perform high speed seeking for optical disks of M-CLV and M-CAV systems by measuring a time interval of a prescribed signal at every reproduced section. CONSTITUTION: A time interval between pre-format parts (address) Ga of respective sectors arranged in the radial direction at every respective areas of plural areas Za-Zd divided in the radial direction on the optical disks of the systems is measured at a seeking time. Thus, the fact that a scanning position of an optical head is any one among plural divided areas Za-Zd on the optical disk is detected surely. Thus, processing after accessing to a target track such as switching of a reference frequency set at every division is performed rapidly, and the optical disks of the M-CLV system and the M-CAV system are sought at high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seek system for recording / reproducing positions on an optical disk.

[0002]

2. Description of the Related Art Conventionally, a constant linear velocity (Constant Linear V) has been used as a recording format of an optical disk.
Electrity) method (hereinafter referred to as CLV method),
Constant angular velocity (Constant Angular Vel
wellness method (hereinafter referred to as CAV method) is well known.

The CLV system controls a spindle motor so that the rotational speed is inversely proportional to the radius of the track on the disk. The linear velocity of the track for recording / reproducing is constant anywhere on the disk, and the sector length on the track. As a result, the recording / reproducing frequency becomes constant over the entire area of the disc and the circuit system becomes complicated, but the recording capacity can be increased.

In the CAV system, the rotation of the spindle motor and the recording / reproducing frequency are made constant, and the circuit system can be simplified, but the recordable data density of the innermost track is restricted. The total recording capacity is reduced.

Taking advantage of the large recording capacity of the CLV system as described above, a simplified modification (Modify) in which the shift control of the spindle motor is performed stepwise.
d) CLV method (hereinafter referred to as M-CLV method), C
A variant in which the recording capacity is increased by gradually increasing the recording / reproducing frequency from the inner circumference to the outer circumference of the disk by taking advantage of the ease of rotation control of the AV system (M
A modified CAV system (hereinafter referred to as M-CAV system) has also been proposed.

In the M-CLV system and the M-CAV system,
In each case, as shown in FIG. 4A, the entire recording area of the disc has a plurality of zones (Za to Z in the figure) in the radial direction.
In each zone, a plurality of sectors (Sa to Sd in the figure) are formed in each zone so as to be aligned in the radial direction for each zone.

As shown in FIG. 4B, the starting point G of each sector
Servo pits for tracking are formed in a, and address information is pre-formatted (pre-pit). The formation angle interval of this pre-formatted portion is such that the sectors are radial in each zone as described above. Since they are aligned, they are constant for each zone. Data is recorded in the data area Gb of each sector.

At the boundary between two adjacent zones, the preformatted portions are not aligned in the radial direction. Therefore, when scanning an adjacent track in another zone, the address information is mixed into the recording or reproducing signal to cause a PLL or the like. In order not to adversely affect the operation of, at least a non-recording area for two tracks is provided.

In the M-CLV type disc, as shown by the solid line in FIG. 5A, the rotational speed increases stepwise from the outer periphery of the disc to the inner side, and as shown in FIG. 5B,
The recording / reproducing frequency is constant over the entire area of the disc.

On the other hand, in the M-CAV type disc, the rotation speed is constant over the entire region of the disc as shown in FIG. 6A, and as shown in FIG. Will gradually increase.

As shown in FIGS. 5C and 6C, the sector length becomes equal at the innermost circumference of each zone of the disc in both the M-CLV system and the M-CAV system. In other words, the linear densities of data in the innermost tracks of each zone are equal.

There is no difference in the format or pattern of the signal recorded on the disc between the M-CLV system and the M-CAV system.

In the M-CAV system, since the number of rotations of the disk is constant, for example, seek time (access time)
Is relatively short at 150 mS, but the data transfer rate is
4MB / S at the outer circumference is reduced to 2MB / S at the inner circumference, and M
In the -CLV method, for example, the seek time is relatively long at 500 mS, but the data transfer rate is constant at 4 MB / S. The M-CLV system is suitable for recording continuous signals such as audio signals and video signals, and is suitable for M-CA.
The V method is suitable for applications such as filing systems for documents.

[0014]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
When performing a seek to access a predetermined track on a V-type or M-CAV type disc at the time of recording or reproduction, it is necessary to read the address of the track via an optical head.

As shown in FIG. 7, in a normal seek state,
Since the optical head is accelerated in the first half Ta of the moving period and is decelerated in the second half Td of the time equal to the first half Ta, the address of the disk cannot be read during the period of high moving speed.

Also, at the end of the seek state, M-
In the CAV method, as shown in FIG. 6B, since the recording / reproducing frequency changes for each zone, the address can be read unless the frequency division ratio of the PLL is set correctly to correspond to this frequency change. Can not.

For this reason, conventionally, in the M-CAV system, a position sensor is attached to a coarse tracking mechanism of an optical head, for example, a linear motor, the absolute position of the mechanism is detected, and according to the detected position, The frequency division ratio of the PLL is set.

However, due to the eccentricity of the disc, the track pitch error, the shift of the center hole during chucking, and the like, a position shift occurs between the position of the position sensor and the track position of the disc, so that the correct track can be accessed. However, there is a problem that the seek time is lengthened because the seek is repeated several times until the seek is completed.

On the other hand, in the M-CLV system, as shown by the solid line in FIG. 5A, the number of revolutions of the disk changes zone by zone, so that the spindle servo is preset in correspondence with the target zone. , The address cannot be read when the optical head is located on a zone different from the target or until the spindle servo locks, and there is a problem that the seek time becomes long as described above. .

In order to solve the above-mentioned problem, it is possible to count tracks crossed at the time of seek, but it is not always accurate because a counting error occurs due to a scratch on the disk.

In view of the above point, the present invention provides the M-CLV.
It is an object of the present invention to provide a seek method for a recording / reproducing position of an optical disk, which enables high-speed seeking of the optical disk of the M-CAV method and M-CAV method.

[0022]

In order to solve the above-mentioned problems, the recording / reproducing system of the optical disk according to the present invention is divided into a plurality of areas Za to Zd in the radial direction when the reference numerals of the embodiments described later are made to correspond. , The linear densities of the data in the innermost tracks of the divided areas are made equal, and the tracks are aligned in the radial direction on a plurality of tracks of the divided areas to form a plurality of sections S,
In the seek method of the recording / reproducing position of the optical disc 1 in which a to Sd are radially formed and a predetermined signal is recorded in the plurality of sections, a predetermined signal is recorded by the optical head 21 facing the optical disc at the time of seek. Is reproduced in a separable state, and the time interval Ti of the reproduced predetermined signal is measured to detect which of the plurality of divided areas of the optical disk the scanning position of the optical head is. It is a feature.

[0023]

According to such a configuration, which of the plurality of divided areas Za to Zd of the optical disk 1 the optical head 21 faces is surely detected, and the reference frequency set for each divided area is switched. It is possible to promptly perform the processing after accessing the target track as described above.
It is possible to perform high-speed seeking of the optical discs of the M-CAV and M-CAV systems.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disk recording / reproducing system according to the present invention will be described below with reference to FIGS.

FIG. 2 shows the configuration of an embodiment in which the present invention is applied to an optical disk device. In FIG. 2, reference numeral 1 is an optical disk, which is driven by a spindle motor 11.
A frequency generator (so-called F
G) The output of 12 and the output of the spindle clock generation circuit 13 are supplied to the phase comparison circuit 14, and the comparison circuit 1
The output of No. 4 is supplied to the motor 11 through the drive circuit 15 to perform spindle servo, and the motor 11 rotates in the M-CLV mode or the M-CAV mode as shown in FIGS. To do.

Reference numeral 21 denotes an optical head, which is a lens 21L.
And an optical system including a beam splitter (not shown), and devices such as a laser diode and a photodetector (not shown). It is moved by the motor 22. This movement is controlled by supplying the output of the feed servo circuit 24 to the motor 22 through the drive circuit 23.

In the optical head 21, a tracking error signal is generated from the output of the photodetector and is supplied to the tracking servo circuit 25 for tracking control. Further, the detection output of the photodetector of the optical head 21 is R
The signal is supplied to the F amplifier 26, and an RF signal as a reproduction signal of the optical disc 1 is generated.

A system control circuit (CPU) 31 is connected to an external host computer 2 through an interface 32. In this embodiment, the interface 32 is a SCSI (Small C) which is an interface standard by the American National Standards Institute (ANSI).
computer Systems Interfac
e) is used. In addition, from the system control circuit 31,
Spindle clock generation circuit 13 and feed servo circuit 24
Control signals are supplied to and.

In this embodiment, the error signal from the tracking servo circuit 25 is converted into the error signal slicer 33.
Through the system control circuit 31,
The output of the RF amplifier 26 is supplied to the address area detection circuit 34, and the output of the detection circuit 34 is supplied to the system control circuit 3
1 is supplied.

The output of the RF amplifier 26 is supplied to the address decoder 36 and the PLL through the address slicer 35.
It is commonly supplied to 37. A control signal is supplied from the system control circuit 31 to the PLL 37, and the PLL 37
Is supplied to the address decoder 36, and the output of the decoder 36 is supplied to the system control circuit 31.

On the optical disc 1 used in this embodiment, which of the M-CAV mode and the M-CLV mode data is recorded in is written in the user control information area of the innermost circumference (lead-in area). The information of this recording mode is taken into the system control circuit 31 when the disc 1 is mounted in the recording / reproducing apparatus.

Normally, the recording mode is M for each disc.
Either one of -CAV and M-CLV is selected,
It is also possible to switch the recording mode for each zone on one disc.

In the latter case, at the time of recording, the M-CAV and M-C are transmitted from the host computer 2 via the SCSI32.
A command as to which mode of LV recording is to be issued, and the recording mode is switched. In this case, normally, one zone is set for one file. Then, a non-recording area for at least two tracks is set at the location where the zones are switched. This is when the optical head scans adjacent tracks in one zone from another,
This is to prevent the pre-pit portion (address, etc.) of the preceding zone from being overwhelmed by the recording / reproducing signal and thus adversely affecting the PLL control and the like.

The optical disc 1 is a write once.
In the case of the Once type (hereinafter referred to as WO type), the reflected light from the disc 1 is small in the preformatted portion Ga of each sector and large in the data recording area Gd as shown in FIG. 3B. Then, the reflectance is increased in the portion where data is recorded in this area Gd. Therefore, the optical head 21
As shown in FIG. 3A, the signal output from the data output device differs from that in the address-corresponding part and the data-corresponding part.

In addition, the optical disk 1 is a magneto-optical (Magne
In the case of the optical optical type (hereinafter referred to as MO type), due to the difference in recording principle, after the reflected light from the disk 1 passes through the beam splitter in the optical head 21, it becomes so-called p-wave and s-wave. The light is separated and detected by the corresponding photodetectors. Then, a sum signal of the output of the photodetector corresponding to the p wave and the output of the photodetector corresponding to the s wave is generated. As shown in FIGS. 3C and 3D,
In this sum signal, an address output signal is obtained at the portion corresponding to the pre-formatted portion Ga of each sector.

As shown in FIGS. 3C and 3D, with the sum signal, an output signal corresponding to the data recording area Gd cannot be obtained, and the output of the photodetector corresponding to the p wave and the light corresponding to the s wave are obtained. By separately generating a difference signal from the output of the detector, an output signal corresponding to the data data recording area Gd can be obtained.

In the address slicer 35, FIG.
Alternatively, by slicing the output of the RF amplifier 26 at a predetermined level Es as shown in FIG. 3C, desired address information can be extracted from the disk 1 regardless of whether it is WO type or MO type.

The extracted address information is supplied to the PLL 37 to generate a reproduction clock. When the reproduced clock is supplied to the address decoder 36 while the PLL 37 is locked, the address information is decoded. That is, you can read the address.

Next, the seek operation of the embodiment of the present invention will be described with reference to FIG.

First, in step 101, when recording or reproducing the disc 1, a target address to be sought is specified from the host computer 2 via the SCSI 32, and in the next step 102, as described above, Based on the information written in the lead-in area, the recording mode of the disc 1 is M-CAV, M-C.
It is checked whether it is an LV.

If the recording mode is M-CAV, the process proceeds to step 103, where the system control circuit 31
The spindle clock generation circuit 13 is set so as to generate a clock having a constant frequency corresponding to the constant rotation speed as shown in FIG. 6A.

In step 104, the system control circuit 31 calculates the number of intersecting tracks that should be traversed from the initial address to the destination address, and generates the required seek signal as shown in FIG. To be done.
This seek signal is supplied to the feed servo circuit 24, the feed motor 22 is driven, and the optical head 21 moves in the radial direction.

In the next step 105, the optical head 21
3A or 3C, the system control circuit 31 causes the system control circuit 31 to measure the zone in which the optical head 21 is currently passing. Can be recognized and the frequency setting signal corresponding to this zone is
The frequency division ratio is set so that it is supplied to 37 and locked.

Then, in step 106, the tracking error signal supplied through the slicer 33 is counted by the system control circuit 31 to count the crossing tracks that have crossed from the initial address to the present time, and calculate the current address. Is calculated.

In the next step 107, PLL3
7 is locked, the optical head 21 is actually positioned, and it is determined whether or not the real address can be read. This determination is made, for example, based on whether the CRC check of the address is OK twice in succession.

When the real address can be read, the real address is replaced with the address calculated in step 106 (step 108), and the process proceeds to step 109. If the real address cannot be read, step 10
The process proceeds from step 7 to step 109.

In step 109, it is judged whether or not the target address has been reached. If the target address has not been reached, the process returns to step 104 and the above-mentioned processing is repeated to perform fine tracking adjustment. Done. Thus, the seek is completed when the target address is reached.

On the other hand, when the recording mode of the disk 1 is M-CLV in step 102, the process proceeds to step 111, and the system control circuit 31 causes the spindle clock generating circuit 13 to move as shown in FIG. 5A. ,
It is set to generate a clock with a frequency that changes corresponding to the number of revolutions of the zone to which the destination address belongs. Then, the process proceeds to step 104, and the above-mentioned MC
The same processing as in the AV mode is performed.

During this period, the rotation speed of the spindle motor 11 gradually increases, and the control signal is continuously supplied from the system control circuit 31 to the feed servo circuit 24 until the target rotation speed is reached.

As described above, in the above embodiment, the M-CL is divided into a plurality of regions Za to Zd in the radial direction.
When seeking the V-type and M-CAV-type optical discs 1, the optical head 21 is actually measured by measuring the time interval Ti of the pre-formatted portion (address) of each sector, which is aligned in the radial direction for each divided area. PLL 37 for distinguishing the facing zones and reproducing the clock
Is controlled so as to be locked, and the count of crossing tracks is also used, so that the address decodable state can be quickly reached and the seek time can be shortened.

Instead of measuring the cycle interval of the pre-formatted (pre-pit) address signal as in the above-mentioned embodiment, if there is a signal obtained at a constant cycle for each zone, Of course, the cycle may be measured at the time of seek.

[0052]

As described above, according to the present invention, by measuring the period of the signal obtained at a different period for each zone of the optical disc at the time of seek, the optical head actually scans at the time of seek of the optical disc. A state in which address decoding is possible by determining which zone is present and controlling the PLL for reproducing the clock so that the PLL is locked and counting the number of tracks at which the scanning position of the optical head intersects at the time of seeking. Promptly arrives, and M-CLV
It is possible to perform high-speed seeking of the optical discs of the M-CAV and M-CAV systems.

Further, the conventional position sensor becomes unnecessary,
The cost can be reduced, the variation of the seek time by the disc is reduced, and the compatibility is improved.

[Brief description of drawings]

FIG. 1 is a flowchart showing the configuration of an embodiment of an optical disc recording / reproducing system according to the present invention.

FIG. 2 is a block diagram showing a configuration of an optical disc device to which the present invention is applied.

FIG. 3 is a waveform diagram for explaining the operation of the embodiment of the present invention.

FIG. 4 is a conceptual diagram for explaining the present invention.

FIG. 5 is a conceptual diagram for explaining the present invention.

FIG. 6 is a conceptual diagram for explaining the present invention.

FIG. 7 is a conceptual diagram for explaining the present invention.

[Explanation of symbols]

 11 Spindle Motor 21 Optical Head 22 Feed Motor 31 System Control Circuit (CPU) 33 Tracking Error Signal Slicer 34 Address Area Detection Circuit 36 Address Decoder 37 PLL 100 Seek Control Routine

Claims (4)

[Claims] 1. A plurality of areas are divided in a radial direction, the linear densities of data in the innermost tracks of each divided area are made equal, and the plurality of tracks of each divided area are aligned in the radial direction. In a seek method of a recording / reproducing position of an optical disc in which a plurality of sections are radially formed and a predetermined signal is recorded in each of the plurality of sections, at the time of seek, the predetermined signal is transmitted by an optical head facing the optical disc. The data is reproduced in a state separable from the data, the time interval of the reproduced predetermined signal is measured, and which of the plurality of divided areas of the optical disk the scanning position of the optical head is located is determined. A seek method for the recording / reproducing position of an optical disc, which is characterized by being detected. 2. The optical disk is rotated at a constant angular velocity for each of the divided areas, and is set for each of the divided areas in order to decode the predetermined signal according to the time interval of the measured predetermined signal. The seek method for recording / reproducing position of an optical disc according to claim 1, wherein the selected reference frequency is switched. 3. The predetermined signal is recorded on the optical disc.
The seek method of the recording / reproducing position of the optical disk according to claim 1 or 2, which is pre-formatted information. 4. The recording / reproducing position of the optical disc according to claim 1, wherein the optical disc is rotated at a constant angular velocity, and the clock frequency of the recording / reproducing data is changed for each of the divided areas. Seek method.