JPS5873064A - Tracking control system - Google Patents

Abstract

PURPOSE:To perform accurate tracking at reproduction, by meandering a recording part having a recording track width slightly narrower than the intervals of recording track in a frequency an integer multiple of the number of revolution of a disc, and recording its frequency together with an information signal. CONSTITUTION:Recordings t1-tn of a recording track width Wt is meandered in concentric or spiral shape at the recording track intervals Wp(Wp>Wt) for recording. The frequency of meandering is single frequency an integer multile of the number of revolutions of a disc, and adjacent tracks are meandered similarly on the radial lines. A signal having the same frequency as the meandering frequency is recorded, being included in an information signal. Or, in recording a television video signal, the meandering frequency is the frequency of a synchronizing signal. Thus, accurate tracking is obtained by using this meandering signal as a servo signal at reproduction.

Description

[Detailed Description of the Invention] When performing high-density recording and reproduction from an information recording medium (disc) K, it is necessary to read the information signal while the reading element (reproducing element) faithfully follows the recording trace on the disc. must be done.

By the way, if the disc is of a type equipped with a guide groove, the S-Yomikanko can faithfully follow the recording trace while being guided by the guide groove provided on the disc, but the guide groove Since it is difficult to rapidly move the reading element in the radial direction of the disk with types of disks equipped with a There is a problem that the playback operation may be difficult.

On the other hand, with discs that do not have guide grooves,
Playback operations such as tom access operations and trick plays can be performed easily, but a tracking control means is required to make the reading element accurately follow the recording trace, and conventionally, for grooveless discs, It is well known that various tracking control methods have been used.

Among the typical tracking control methods for grooveless discs, the method using multiple reading light beams has a complicated optical system configuration and is not applicable to recording/reproducing systems other than optical recording/reproducing methods. Moreover, it is difficult to record a plurality of pilot signals with different frequency values on a disk, and when reading information signals from the disk, it is difficult to read the plurality of pilot signals with six different frequency values recorded on the disk. In the system in which the tracking control is performed using the above-described method, there are problems in that the configuration for recording pilot signals becomes complicated, and a switching mechanism for each pilot signal is required at the time of reproduction.

As a tracking control method that can solve the above-mentioned problems, an attempt is made to perform tracking control using one par (by the q-nod signal) recorded in the record trace of the main information signal. Also published in Japanese Unexamined Patent Publication No. 54 (1973) 734.391
It is disclosed in the publication No. That is, JP-A-55-34
The technical means disclosed in Publication No. 391 is as follows:
The pilot signal in the circumferential recording trace is set to have a predetermined phase difference with respect to the pilot signal in the one circumferential recording trace before and after that one circle, and the pilot signal is recorded on the disk. A tracking control signal is generated by comparing a phase reference signal and a pilot signal. However, in this known tracking control method, the pilot signal is recorded in the record trace of the main information signal, so , a sudden large tracking control signal is generated only when the reading element is displaced to the state K where it can also read information signals from adjacent recording traces, so the tracking control becomes unstable in a so-called "ball-up" state, and playback becomes unstable. Crosstalk may occur in the signal, the processing/vep of the reproduced signal may be amplitude modulated, and the reproduced image quality may deteriorate.Of course, the phase reference signal recorded on the disc may not be the same. Since the phase portions are recorded on the disk in a state that is not aligned in the radial direction of the disk, when the reading element crosses the recording traces one after another, the phase of the phase reference signal changes from one recording trace to the next. The problem was that it was difficult to perform tracking control because of the change.

The present invention has been made for the purpose of providing a tracking control method that does not have the problems of the conventional tracking control methods as described above. A detailed description will be given with reference to the accompanying drawings.

In the tracking control method of the present invention, the inside of the recording trace (track width) Wt and the recording trace interval (track pitch) are Wt
This is applied to information recording media disks on which concentric or spiral recording traces with a relationship such as In addition to forming information signals on the disk that are spatially meandering at frequencies, the recording traces include information signals that are subject to internal recording ((, the above-mentioned single frequency that is an integer multiple of the rotational speed of the disk). A modulated wave signal modulated by a reference signal having the same frequency and wave number is also recorded, and when reading the information signal from the disk,
A tracking control signal is obtained by synchronously detecting the signal component corresponding to the spatial meandering information of the recording trace included in the reproduction signal read from the disk and the reference signal, and the tracking control signal is thereby obtained. Tracking control is performed by driving.

The tracking control method of the present invention as described above is applicable to an information signal recording and reproducing method other than an information signal recording and reproducing method in which the information signal is read from a disk by detecting a change in capacitance value. However, in the following description, the tracking control method of the present invention will be applied to an information signal recording/reproducing method in which the information signal is read from a disk by detecting a change in capacitance value. A case in which the method is applied will be described using an example.

FIG. 1 is a partially cross-sectional perspective view of a tameno disk for illustrating and explaining the dimensional relationship between the recording trace Wt and the recording trace interval in the recording traces formed on the disc D, and the relationship between the disc D and the playback needle S. So, in this Figure 1, t, l
t2... is the pit 1 according to the information signal. It is a record trace formed by the arrangement of l..., and also 2,
2... is a non-recorded portion formed between adjacent recording traces, and in the disc D shown in FIG. It is considered a thing. In addition, in FIG. 1, S is a reproducing needle, and this reproducing needle S is equipped with an electrode E having a slightly narrower electrode width than Wt in the recording trace, and the surface of the disk D is covered by a sliding surface with a wide area. It is in contact with

The disk D shown in FIG. 1 is made of a resin material made of a copolymer of vinyl chloride and vinyl acetate, for example, mixed with fine carbon powder to give it conductivity, and the uneven pattern of the stamper is It can be made by transcribing. In the disk D shown in FIG. 1, the recording trace L1+
L2... are formed on the disc D such that the Wt in the recording trace and the recording trace interval Wp have a relationship of WtC%p, and each recording trace tI+L2... is formed on the disc D It has a spatially meandering shape with a single frequency that is an integral multiple of the number of rotations.

Therefore, when the disk D rotates while the playback stylus S equipped with the electrode E having an electrode width slightly narrower than the recording trace Wt is placed at a specific radial position on the disk n, the playback stylus S The change in the capacitance value between the electrode E of the playback needle S and the disk D detected by the electrode E is the change in the capacitance value based on pits 1, 1, etc. in the recording trace that the playback needle S is tracing. This is due to both the amount of change in capacitance value that occurs in response to the spatial meandering of the recorded trace.

Therefore, in addition to the information signals that are originally recorded and reproduced by the disk, the recording trace of the disc D is modulated by a reference symbol having the same frequency as the frequency of the spatial meandering of the recording trace. Also record the modulated wave signal,
When reading the information signal from the disc D, tracking is performed by synchronously detecting the signal component corresponding to the spatial meandering information of the recording trace included in the reproduction signal read from the disc D and the reference signal described above. A control signal can be obtained, and by driving the reading element, the reading element can be caused to correctly follow the recording trace.

In the disk D of the configuration example shown in the first diagram, there is a recording trace tI.

In order to enable the playback needle S to detect the frequency component caused by the spatial meandering of t2... as a change in capacitance value, each recording trace t4
A groove with a V-shaped cross section is provided in the non-recorded portions 2', 2... between , t, . For example, in a disk D as shown in FIG. 2, which has a configuration in which grooves are not formed in the non-recorded portions 2, 2, . . . between the respective recording traces jl+L2 . Even if there is such a problem, the tracking control method of the present invention can be applied satisfactorily.

On disc D, the information signal that is originally the target of recording and reproduction is a television video signal (hereinafter referred to as television video signal).
(abbreviated as ), an audio signal, a PCM signal of an audio signal, and various other information signals. When a periodic signal having a frequency that is an integral multiple of a number is included, the periodic signal can never be used as the reference signal described above. For example, the information signal to be recorded and reproduced on a disc is a TV video signal, and the TV video signal has a horizontal scanning frequency fh and a vertical scanning frequency fv.

If the TV video signal is made according to a scanning standard in which one frame of TV video signal is created by 2:1 interlaced scanning, the TV video signal recorded in one recording trace of one circumference of the disc is 1 frame. If the rotational speed of disk D is determined to be an integral multiple of Freno, then the horizontal synchronization signal in the TV signal recorded on disk DK will have a repetition frequency that is an integral multiple of the rotational speed of disk D. Since it is related to frequency, the horizontal synchronization signal in the TV video signal recorded on disc D can be used as the reference signal mentioned above, and the TV video signal can be used when recording it on disc D. is a recording signal in the form of a signal such as an FM wave signal, so the horizontal synchronization signal used as a reference signal is also recorded on the disc D in the form of a modulated wave signal, so that the recording traces are A reference signal having four frequencies equal to the meandering frequency is frequency-division multiplexed with the information component generated as a result of the spatial meandering of the recording trace on the disc D at 9 times when the information signal from the disc D is read. The vines are regenerated in a separable manner.

As in the above example, when the horizontal synchronization signal in the TV video signal is used as the reference signal, the frequency of the spatial meandering of the recording trace on disk D is:

This is the frequency of the horizontal synchronizing signal in the TV video signal to be recorded and reproduced on the disc D.

When a signal with a frequency that is an integral multiple of the rotational frequency of the disk D is recorded on the disk D, portions of the same phase in the recorded signals are aligned in the radial direction of the disk D. Yes, as shown in Figures 6 and 7 below.
The dotted line in the figure represents the recording location of the reference ugly signal on the disc D.

A disk D having a configuration as shown in FIG. Disk D is in a state of being meandered spatially at a frequency of
The following is an explanation of how it is made with reference to FIGS. 3 to 5.

In FIG. 3, reference numeral 3 denotes a master disk, and the master disk 3 is rotated at a predetermined number of rotations N (rpm) by a drive device (not shown). 4 is an electromagnetic drive element, 5 is a piezoelectric drive element, and 6 is a diamond cutting needle. The piezoelectric drive element 5 vibrates in the direction of the arrow Y in the figure when an information signal is applied to it. A diamond cutting needle 6 vibrates on the surface of the disk master 3 in the radial direction X of the disk master 3 at a frequency fp that is an integral multiple of the information signal rotation number N, and a recording trace is spatially sinusoidal at the frequency fp. Make it meanderingly.

Frequency fp of a signal that causes the diamond cutting needle 6 to vibrate in the radial direction of the disk master 3 by the electromagnetic drive element 4
As mentioned above, is the same as the frequency of the reference signal recorded in the form of a modulated wave signal in the recording trace of the master disk 3 of the disk, so now, the frequency recorded between the master disk 301 of the disk It is assumed that a signal of an integral multiple of one frame of the TV video signal is recorded in the trace, and when the horizontal synchronization signal in the TV video signal is used as a reference signal, the diamond cutting needle 6 described above is inserted into the master disc of the disc. The frequency fp of the signal for vibrating in the radial direction of No. 3 is made the same as the repetition frequency fh of the horizontal synchronizing signal in the TV video signal.

Further, the reference signal described above and the signal for vibrating the diamond cutting needle 6 in the radial direction of the disk master 3 have a predetermined specific phase relationship with each other.

FIG. 4 is a diagram illustrating and explaining the state in which the disk master 3 is cut by the diamond cutting needle 6 in FIG. The surface is sequentially cut at a constant pitch P (same as the rack pitch Wp). A recording trace in which the pits are arranged is formed (in FIG. 4, the pits formed on the master disc 3 due to the vibration of the diamond cutting needle 6 in the vertical direction Y by the piezoelectric element 5 are simplified in the illustration). For this reason, illustration is omitted. This point also applies to FIGS. 5 and 6).

Transversely feeding the diamond cutting needle 6 in the radial direction of the disk master 3 at a predetermined pitch P is performed by transversely feeding the electromagnetic drive element 4 by a transfer mechanism (not shown). In the disk D, when the track pitch is, for example, 2 μm, the tire cutting needle 6 moves in the radial direction X of the disk master 3 every rotation of the disk master 3.
It is only necessary to horizontally feed the sheet by 2 μm at a time. In addition, the width of the tip of the die A'-7-dot cutting needle 6 is made to correspond to the track width, but in the case of the above example, the width of the tip of the tire cutting needle 6 is smaller than F12 μm. chosen small.

The amplitude of the vibration of the diamond cutting needle 6 in the X direction caused by the electromagnetic drive element 4 is determined by the recording trace 1. ．． 1. ... is determined, and the amplitude of the spatial meandering of the recorded trace is determined appropriately according to various requirements such as the length of the recorded trace, the interval between recorded traces, and the electrode width of the reproducing needle S. For example, the interval between recorded traces is 2 μm, the inside of the recorded trace is 15 μm, and the reproduction needle S
When the electrode width is 08 μm, the amplitude of the spatial meandering of the recorded trace should be selected to be, for example, about 02 μm in peak-to-peak value.

To make a disc D as shown in Figure 1 using a disc master made by a recording device as shown in Figure 3,
It is possible to use the master disk L-code and adopt the same technique as in making the J-code, but the cross-sectional shape of the disk master 3 shown in FIG. 4 and the one shown in FIG. The cross-sectional shape of the disk D shown in FIG. Make sure that those with the same unevenness are used.

FIG. 5 is a front sectional view of the disk D, and in this FIG. 5, as in FIG.
Therefore, the diagram shows a state in which the electrode E of the reproducing needle S in sliding contact faces a specific recorded trace.

Next, Figures 6(a) to (ε) to Figures 9(,j to (C
) What kind of truck blowfish control operation is performed by the trunking control method of the present invention will be explained with reference to the figure. FIG. 6(a) shows an unrecorded portion 2. between adjacent recording traces t, It2, . . . as shown in FIG.
2 is an enlarged plan view of a part of a disk D having a configuration in which grooves having a V-shaped cross section are formed, and the portions indicated by dotted lines in the figure are as described above. This is the recording position of a certain phase part of the reference signal recorded on the disc D, and this recording position is aligned in the radial direction on the disc D, and exhibits a radial pattern in the disc D. be.

In addition, Fig. 6 (a) shows the cross section of the disk D.
6(C) shows the direction in which the reproducing needle S is driven by the tracking control.

Fig. 6 (In Fig. a1, S is the regenerated needle, E is the electrode of the regenerated needle S, and the electrode E indicated by 0 in the figure is the electrode E of the regenerated needle S.
This shows the case where the electrode E is located at a position tracing the center of the recording trace, and the electrode E shown as la, 2a+3a+1b+2b, and 3b in the figure
The relative positional relationship between the electrode E of the playback needle S and the recorded trace is 1 a + 2 a + · in FIG. 6(a), respectively.
...The case is shown in the position shown by 3b. Figure 6 (
In the ai diagram, the following description will be made assuming that the upper side of the figure corresponds to the inside of the disk P, and the lower side of the figure corresponds to the outside of the disk D.

In Figure 7, 3a+2a+1a+O+1b+2b+3
Each curve displayed like b is the electrode E of the regenerated needle S.
is at position 00 in Figure 6 (,), for example, and when it moves on the disk as shown by line t in the Kerr diagram, it is detected by electrode E in correspondence with the meandering information of the recording trace. The manner in which the capacitance value changes is shown by the curve O in FIG.
When it is located at position 1a in the figure and moves on the disk parallel to line t in the Kerr diagram, the change in capacitance value detected by electrode E corresponds to the meandering information of the recording trace. With the correspondence shown by the curve 1a in FIG. 7, information on the meandering of the recorded trace at each position of the electrode E of the playback needle S in FIG. 6(a) and Correspondingly, it is a curve diagram showing the mode of change in the capacitance value detected at the electrode E of the regeneration needle S, and in each curve in this FIG. 7, the portion above the center line shows the capacitance value. The graph shows that the city's output is due to an increase in , and the area below the center line is a negative output due to a decrease in capacitance value.

Comparing FIG. 6(a) and FIG. 7, we can see that when the electrode E of the reproducing needle S is at the inner end 1a (3b) of the recorded trace and when the electrode E of the reproducing needle S is at the position of the outer end 1b (3a ), outputs of opposite polarity are obtained at t! It costs 11.

Therefore, if the information and the reference signal recorded on the disk D are synchronously detected based on the meandering of the recorded trace on the disk D detected by the electrode E of the playback needle S, a tracking control signal can be obtained. is clear.

FIG. 8 is a block diagram showing an example of a circuit arrangement for generating a tracking control signal from a reproduction signal reproduced from a reproduction stylus S functioning as a reading element. In FIG. 8, S is a reproduction stylus, and PrA is a Various types of information detected as changes in electrostatic capacity at the electrode E of the reproducing needle S are converted into electrical signals in the preamplifier PrA, amplified, and sent to the single-wavelength band filter BPF and FM demodulator. device DIM.

The above-mentioned bandpass filter BPF extracts the frequency component of the meandering recording trace from the reproduced signal from the disk drive D, that is,
A signal component Sfp (FIG. 9(a)) having a frequency of fp is extracted and applied to the multiplication circuit ①. If the frequency of the meandering information of the recorded trace is outside the 441 frequency band of the FM wave signal, the signal component can be easily extracted by the bandpass filter BPF. FM demodulation 5DE mentioned above! In vl, the FM wave signal reproduced from disk D is demodulated and applied to the color process CLR, which creates a color composite image signal and supplies it to the subsequent circuit. Further, the output signal from the above-mentioned FM demodulation circuit DEM is applied to the synchronization separation circuit SEP to obtain a horizontal synchronization signal, which is applied to the monostable multivibrator MMK.

The monostable multi-bibreak is used for waveform shaping of the equalization pulse portion. Figure 9(b) shows the output signal ph of the monostable multi-pie break claw.
This signal ph is applied to the phase locked loop PLL. A horizontal synchronizing signal with an improved S/N ratio and a continuous reference signal Sr (FIG. 9(C)) having the same frequency are outputted from the phase-locked loop PLL and supplied to the multiplication circuit MUL described above. be done.

The output from the multiplication circuit obtained by the multiplication operation in the multiplication circuit, that is, the synchronous detection operation, is passed through the low-pass filter LP.
F, and from the low-pass filter LPF, a signal component required for the operation of the tracking control system, for example, 2KHz
The following signal components are extracted and supplied to the tracking control system π, and in the tracking control system, an actuator drives the reproducing needle S according to the tracking control signal so that the reproducing needle can accurately trace the recorded trace. Make it.

FIG. 6(C) shows how the regeneration needle at six different positions in FIG. 6(a) is controlled by the tracking control signal generated by the circuit arrangement shown in FIG. The arrow in FIG. 6(C) indicates the direction of movement of the regenerating needle S, and the black circle mark in the figure indicates the stable point, The white circle mark is the Keyaki stability point. Therefore, in the tracking control of the playback needle S by the tracking control method of the present invention, the information based on the meandering V of the recorded trace is used to
If tracking control is applied so that the regeneration needle S is driven and displaced in the direction (upward direction in FIG. 6(a)), the regeneration needle S
(C) Stable tracking control is performed by driving displacement in the direction of the arrow in the figure. In addition, in the tracking control method of the present invention, the position of the electrode E of the regenerating needle S is as shown in FIG.
If the track pitch is between σ and 2a and 2b in the figure, the reproduction needle S is stabilized at the position indicated by the black circle in FIG. 6(C).

In addition, in the tracking control method of the present invention, the reference signals are aligned in the radial direction of the disc D, so even when the playback needle crosses the recorded trace diagonally (tracking control is open), the reference signals are aligned. This means that the control can be started quickly.

Up to now, the explanation has been about the case where the torso control method of the present invention is implemented using the disk D having the configuration shown in the first diagram.
The track control method of the present invention can also be implemented using a disk having the configuration shown in FIG. When implemented, the polarity shown in FIG. 6(c) and FIG. 7 is simply reversed, and the operating principle of the track/g control remains the same as in the previously described embodiment. There is no difference.

As is clear from the detailed explanation above, the Torano-Young control method of the present invention causes the recorded trace on the disc to meander at a frequency that is an integral multiple of the rotational speed of the disc, and also to A modulated wave signal modulated by a reference signal of the same frequency is recorded in the recording trace, and when reading the information signal from the disc, the recording trace included in the reproduced signal read from the disc is recorded. Since the reading element is controlled using a torso control signal obtained by synchronously detecting a signal component corresponding to spatial meandering information and the reference signal, the conventional example described above Therefore, it was possible to easily provide a toranog V-7 engine control system that satisfactorily solved the problems described above.

[Brief explanation of drawings]

Figures 1 and 2 are perspective cross-sectional views of a portion of the tape, and Figure 3 is a front view of a portion of the recording device relative to the master disc.
Fig. 4 shows an enlarged front cross-sectional view of a portion of the disc master formed by cutting, Fig. 5 is a front view showing the relationship between the disc and the playback needle, and Fig. 6 (a). 6(b) is a cross-sectional view of the upper side of the disk, FIG. , 1 to (c) are explanatory waveform diagrams, and FIG. 8 is a boot diagram showing an example of the configuration of a circuit that generates a toraneau V-/G control signal. 1...Bit, 2...No recording Part 3... Disk master, 4... Electromagnetic drive element, 5... Piezoelectric drive element, 6... Diamond cutting needle, D... Disc, S... Playback needle, E... Electrode, BPF... Bandpass filter, DEM... FM recoverer, JL... Multiplier, SEP... Synchronous separation circuit, m-... Monostable multi-noise (ibrator) , LPF...Low pass filter, TS...
・Toratsusen/g control circuit・-' / / 'I) 3 Figure

Claims (1)

[Scope of Claims] A tracking control method for an information recording medium disk in which concentric or spiral recording traces are formed, where Wt in the recording trace and the recording trace interval have a relationship such as wtmp, The above-mentioned recording trace is assumed to meander spatially at a single frequency that is an integral multiple of the number of revolutions of the information recording medium disk. In addition to the information signal, a modulated wave signal modulated by a reference signal having the same frequency as a single frequency that is an integral multiple of the rotation speed of the information recording medium disc is also recorded, and the information recording medium is When reading the information signal from the disk, synchronously detect the signal component corresponding to the spatial meandering information of the recording trace included in the reproduced signal read from the information recording medium disk and the reference signal. A tracking control method in which a tracking control signal is obtained by using this method, and the paper reading element is driven by the tracking control signal to perform tracking control.