JPH06176489A - Recording and reproducing medium and method and device for recording and reproducing - Google Patents

Abstract

PURPOSE:To evade inconvenience erroneously detecting a unique pattern as a gap by easily detecting the unique pattern without mistaking for the gap electrically. CONSTITUTION:In a magnetic disk 1 provided with a servo area where a clock mark being a reference for forming a system clock signal and a servo mark used for detecting a tracking error are recorded, a data area Zd for recording and reproducing a data signal and gap areas Zg1 and Zg2 respectively between the servo area Zs and the data area Zd, this disk is provided with the unique pattern Pu at least showing a position in a circumference direction, and is constituted so that the signal different from the unique pattern Pu is recorded previously on the gap areas Zg1 and Zg2. In such a case, the signal to be recorded on the gap areas Zg1 and Zg2 may be e.g. the all signals showing '1' logically or may be the signals showing '1' and '0' alternately logically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing medium represented by an optical disk, a magnetic disk and a magneto-optical disk, and in particular, an improvement of a sample servo type recording / reproducing medium and information for the recording / reproducing medium. The present invention relates to a recording / reproducing apparatus that digitally records and reproduces signals and a method of recording and reproducing information signals when the recording / reproducing medium is a magnetic disk.

[0002]

2. Description of the Related Art A technique for obtaining a system clock necessary for the operation of a recording / reproducing apparatus from a clock mark recorded on a disk has been put to practical use as a sample servo format in, for example, an optical disk and a magnetic disk.

FIG. 17 shows the structure of a conventional sample servo type magnetic disk 101. In the magnetic disk 101 of the sample servo system, a data area Zd in which an information signal is recorded and a servo area Zs in which servo information and the like are recorded in advance are provided. The servo area Zs includes a servo mark Ms and a clock. The mark Mc is formed as a so-called pre-pit.

Therefore, the magnetic head has the clock mark Mc.
The system clock signal can be obtained by multiplying the clock pulse obtained each time it passes above.

Further, recently, as shown in FIG. 18, even if the magnetic head is off track with respect to the track center Tc, the clock mark Mc can always be detected with a high S / N so that the clock mark Mc can be detected. Has been proposed as a substantially radial pattern that is continuous in the radial direction of the magnetic disk 101.

In an actual recording / reproducing apparatus,
In order to know the position of the clock mark Mc on the disk 101 in the circumferential direction, a code that does not appear in the data part and the servo part, a so-called unique pattern Pu, is formed in several unique areas Zu prepared in the track, and this unique pattern Zu is formed. A method of creating a window for a clock mark by detecting the pattern Pu is used.

As the data recorded in the data area Zd, a modulation code such that "0" does not last long logically is usually used for the purpose of clock reproduction or for eliminating the direct current component contained in the data. Therefore, as the unique pattern Pu, a pattern in which "0" continues for a long time is used as shown in the figure.

[0008]

By the way, between the servo area Zs and the data area Zd, normally, a gap area Z in consideration of time such as switching of a recording / reproducing amplifier is provided.
g1 and Zg2 are provided, but this gap area Z
Since no data is recorded in g1 and Zg2, it is an area where a reproduction signal cannot be obtained.

Therefore, the gap areas Zg1 and Zg2 are
The signal reproduced from is logically similar to a signal in which “0” continues for a long time, and may be electrically mistaken as the unique pattern Pu. In particular, the gap area (for example, Zg2) is provided immediately next to the unique pattern Pu.
If a recording format in which there is is present, the erroneous detection becomes remarkable, and there arises a problem that the position of the clock mark Mc in the circumferential direction cannot be accurately detected.

The present invention has been made in view of the above problems, and an object thereof is to provide a recording / reproducing medium capable of avoiding the inconvenience of erroneously detecting a unique pattern and a gap. is there.

It is another object of the present invention to provide a recording / reproducing medium capable of easily detecting a unique pattern without electrically mistaking it as a gap.

Further, according to the present invention, when the recording / reproducing medium is a magnetic disk, when the recording of the information signal by the magnetic head is switched to the reproduction, the magnetization information recorded in the gap by the residual recording current from the magnetic head. It is to provide a recording / reproducing method capable of avoiding the inconvenience of being destroyed.

Further, according to the present invention, when the recording / reproducing medium is a magnetic disk, when the reproduction of the information signal by the magnetic head is switched to the recording, the recording current is recorded in the gap by the recording current in the transient period from the magnetic head. It is to provide a recording / reproducing method capable of avoiding the inconvenience that the magnetization information is destroyed.

It is another object of the present invention to provide a recording / reproducing apparatus capable of easily and accurately detecting a unique pattern by distinguishing it from a gap.

[0015]

According to the present invention, a servo area Zs having a head positioning signal recorded on the same surface, a data area Zd for recording / reproducing a data signal, the servo area Zs and the data area Zd. Between the cap area Zg1
In the recording / reproducing medium having Zg2 and Zg2, a unique pattern Pu indicating at least a position in the circumferential direction is provided, and a signal different from the unique pattern Pu is recorded in advance in the gap regions Zg1 and Zg2.

In this case, the gap regions Zg1 and Zg2
The signal recorded in the field may be, for example, a signal that all logically indicates "1", or a signal that logically indicates "1".
Alternatively, a signal that alternately represents "0" may be used.

Further, according to the present invention, a servo area Zs in which a head positioning signal is recorded on the same surface, a data area Zd for recording / reproducing a data signal, and a cap between the servo area Zs and the data area Zd. Regions Zg1 and Zg2
In a recording / reproducing method of recording / reproducing an information signal on / from a magnetic recording medium 1 having a magnetic recording medium 1, the magnetic recording / reproducing medium 1 is provided with a unique pattern Pu indicating at least a position in the circumferential direction, and a gap region Zg1 is formed. And Z
A signal different from the unique pattern Pu is recorded in g2 in advance. When the recording of the information signal by the magnetic head is switched to the reproduction, when the magnetic head passes the rear end of the data area Zd, the current applied to the magnetic head is switched from the recording current to the reproduction current, and immediately before the switching. The polarity of the recording current is selected so as to generate a magnetic field in the same direction as the magnetization direction of the signal recorded in the gap area Zg1.

Further, according to the present invention, an information signal is applied to a magnetic recording medium 1 having a servo area Zs in which a head positioning signal is recorded on the same surface and a data area Zd for recording / reproducing a data signal by a magnetic head. In the recording / reproducing method of performing recording / reproducing of 1., a unique pattern Pu indicating at least a position in the circumferential direction is provided on the magnetic recording / reproducing medium 1, and a signal different from the unique pattern Pu is recorded in advance in the gap regions Zg1 and Zg2. Then, when the reproduction of the information signal by the magnetic head is switched to the recording, when the magnetic head passes the rear end of the servo area Zs, the current applied to the magnetic head is switched from the reproduction current to the recording current and immediately after the switching. The polarity of the recording current is selected so as to generate a magnetic field in the same direction as the magnetization direction of the signal recorded in the gap region Zg2.

Further, according to the present invention, the servo area Zs in which the head positioning signal is recorded on the same surface, the data area Zd for recording / reproducing the data signal, and the servo area Zs and the data area Zd are provided. Cap area Zg1
In the recording / reproducing apparatus that records and reproduces information signals on / from the recording / reproducing medium 1 (or 31) having Zg2 and Zg2, the recording / reproducing medium 1 (or 31) is provided with a unique pattern Pu indicating at least a position in the circumferential direction. , And a signal different from the unique pattern Pu is recorded in advance in the gap areas Zg1 and Zg2. Then, the unique pattern Pu is added to the gap areas Zg1 and Zg in the recording and reproducing apparatus.
g2 and a means 53 for detecting separately.

[0020]

In the recording / reproducing medium according to the present invention, in the gap areas Zg1 and Zg2, a signal different from the unique pattern Pu, for example, in the recording / reproducing medium of the present invention according to claim 2, all are logically ". The signal indicating "1"
Alternatively, in the recording / reproducing medium according to the third aspect of the present invention, a signal that logically represents "1" and "0" alternately is recorded in advance.

On the other hand, in the unique pattern Pu, in order to distinguish it from the data recorded in the data area Zd, a signal in which logical "0" continues for a long time is recorded.

Therefore, the signals recorded in the unique pattern Pu and the gap areas Zg1 and Zg2 are easy to electrically discriminate.

A magnetic recording / reproducing medium 1 is used as the recording / reproducing medium.
Applied to the magnetic head, the residual recording current d from the magnetic head when the recording of the information signal by the magnetic head is switched to the reproduction.
Iw causes a problem that the magnetization information recorded in the gap region Zg1 is destroyed.

Therefore, according to the recording / reproducing method of the present invention as set forth in claim 4, when switching from recording of an information signal by the magnetic head to reproduction, when the magnetic head passes the rear end of the data area Zd, The current applied to the head is switched from the recording current to the reproducing current, and the polarity of the recording current immediately before the switching is selected so as to generate a magnetic field in the same direction as the magnetization direction of the signal recorded in the gap region Zg1. Therefore, the disadvantage that the magnetization information in the gap region Zg1 is destroyed by the residual recording current dIw does not occur.

The recording / reproducing medium is the magnetic recording / reproducing medium 1.
In the case of the above, when the reproduction of the information signal by the magnetic head is switched to the recording, the recording information iw in the transition period from the magnetic head causes a problem that the magnetization information recorded in the gap region Zg2 is destroyed.

Therefore, according to the recording / reproducing method of the present invention as defined in claim 5, when the reproduction of the information signal by the magnetic head is switched to the recording, the magnetic head is passed when the magnetic head passes the rear end of the servo area Zs. The current applied to the switch is switched from the reproducing current to the recording current, and the polarity of the recording current immediately after the switching is selected so as to generate a magnetic field in the same direction as the magnetization direction of the signal recorded in the gap region Zg2. Recording current i during the above transition period
The problem that the magnetization information of the gap region Zg2 is destroyed by w does not occur.

Further, in the recording / reproducing apparatus of the present invention as defined in claim 6, since the means 53 for detecting the unique pattern Pu separately from the gap areas Zg1 and Zg2 is provided, the unique pattern Pu is detected in the gap area. It is possible to perform detection separately from Zg1 and Zg2. In particular, the recording / reproducing medium 1 (or 31) is provided with the unique pattern Pu indicating at least the position in the circumferential direction, and the unique patterns Pu are provided in the gap regions Zg1 and Zg2.
Since a signal different from that is recorded in advance, the unique pattern Pu can be easily detected by the means 53.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments in which the recording / reproducing medium according to the present invention is applied to a magnetic disk and an optical disk will be described below in detail with reference to the drawings.

Embodiment 1 First, an embodiment in which the recording / reproducing medium according to the present invention is applied to a sample servo type magnetic disk will be described.
That is, in the magnetic disk 1 of the present embodiment, as shown in FIG. 1, a data area Zd in which an information signal is recorded,
A servo area Zs in which servo information and the like are recorded in advance is provided.

In the servo area Zs, servo marks Ms and clock marks Mc are formed as so-called prepits. Further, in order to know the position of the clock mark Mc on the magnetic disk 1 in the circumferential direction,
Codes that do not appear in the data portion and the servo portion, so-called unique patterns Pu, are formed in the unique areas Zu arranged at several locations (two locations in the illustrated example) in the track. Since this unique pattern Pu is provided to know the circumferential position of the magnetic disk 1, a code that is not used as data recorded in the data area Zd is selected. That is, normally, the data area Zd
For the data in (1), a modulation code with a limited 0 run length is used so that "0" does not last long for the reason of, for example, clock recovery or elimination of the DC component contained in the data.

Therefore, the unique pattern Pu is logically "0" so that it can be easily distinguished from them.
Is used for a long time. In the present embodiment, as shown in FIG. 2, for example, logically "110000000
A pattern serving as a signal of "00011" is formed.

Further, the servo area Zs and the data area Z
Between d, gap areas Zg1 and Zg2 are usually provided in consideration of time such as switching of the recording / reproducing amplifier. In the magnetic disk 1 according to the present embodiment, signals similar to the clock mark Mc are recorded in the gap areas Zg1 and Zg2.

The pattern recorded in the gap areas Zg1 and Zg2 (hereinafter, referred to as a gap pattern for convenience) is different from the unique pattern Pu, so logically "0" does not continue. Use different patterns. Since the gap areas Zg1 and Zg2 are areas in which data cannot be recorded / reproduced, the signal is not reproduced as information, and the pattern density may be reduced.

Therefore, the gap areas Zg1 and Zg2
As shown in FIGS. 3 and 4, for example, the pattern formed in is a pattern in which all are logically “1” (see FIG. 3), or logically “1” and “0” alternate. 0 run len, such as patterns that appear (see Figure 4)
It is desirable to use a pattern that provides a logical code with a small gth. 2 to 4, each figure A shows a pattern shape, each figure B shows a signal waveform of a reproduced signal by a head amplifier, and each figure C shows a logical code corresponding to the reproduced signal.

The example shown in FIG. 5 shows an example in which a step is provided between the recording track 32 on which data is recorded and each mark (Mc, Ms) and each pattern (GP1, GP2, Pu). That is, FIG. 5 shows an example in which each mark (Mc, Ms) and each pattern (GP1, GP2, Pu) is composed of a convex portion and a concave portion, and the recording track 32 is a convex portion.

Next, the magnetic disk 1 according to the present embodiment described above.
The manufacturing method will be described with reference to FIGS. 6 and 7. This manufacturing method is almost the same as the method of manufacturing an optical disc, and the optical recording device (laser cutting device) shown in FIG.

As shown in the figure, this apparatus is basically a turntable 12 on which a smooth circular substrate 11 such as glass is placed, a gas laser light source 13 using a gas as an amplifying medium, and this gas laser. An acousto-optic modulator (Acousto Optic Modulator; hereinafter simply referred to as AOM) 14 for intensity-modulating a laser beam L emitted from a light source 13 based on an ultrasonic wave W modulated by a recording pattern signal Sw, and this AOM 14 And a mirror 16 for guiding the intensity-modulated laser beam L to the objective lens 15.

The substrate 11 is fixed on the turntable 12 by, for example, vacuum suction, and the turntable 12 is a spindle motor (not shown).
Is driven to rotate by, for example, CAV
It is designed to rotate in a (constant angular velocity) system. A photoresist film 17 is coated on the entire surface of the substrate 11. The objective lens 15 is arranged on the photoresist film 17 so as to face each other at a predetermined interval, and is moved in the radial direction of the substrate 11 together with the mirror 16 by a known moving mechanism mainly including, for example, a stepping motor. ing.

Here, when the photosensitive material of the photoresist film 17 is a positive type, the laser beam L is A
458 nm for r laser, 442 for He-Cd laser
The oscillation wavelength of nm is selected. Also, recently
A Kr laser having an oscillation wavelength near 400 nm may also be used. These gas lasers 13 are emitted as a linearly polarized laser beam L through the Brewster window.

On the other hand, an ultrasonic wave generator 18 is connected to the AOM 14, and the ultrasonic wave generator 18 outputs the generated ultrasonic wave to a recording pattern signal (to the photoresist film 17) supplied to an input terminal. The recording pattern to be drawn is modulated on the basis of a signal Sw that is electrically converted. The ultrasonic wave W modulated by this ultrasonic wave generator 18 is
Supplied to the AOM 14.

The AOM 14 is composed of, for example, a TeO ₂ crystal, and uses a phase diffraction grating due to the change in the refractive index generated in the crystal by the ultrasonic wave supply from the ultrasonic wave generator 18, and the Bragg diffraction 1 The secondary diffracted light is used for signal recording. The intensity of the diffracted light is determined by the ultrasonic power, and the diffraction direction is determined by the carrier frequency.

The recording pattern signal Sw is created by the pattern generator 19. This pattern generator 19 is
The recording pattern signal Sw is created based on the clock signal Sc generated in L20. The PLL 20 uses the clock signal Sc based on the rotation timing signal St from the rotary encoder 21 attached to the spindle motor.
To generate.

Next, a method of manufacturing a master disk of the magnetic disk 1 according to this embodiment with the above laser cutting apparatus will be described.

First, a smooth circular substrate 11 such as glass is polished, and a photoresist film 17 is applied on the substrate 11. After that, the substrate 11 is fixed on the turntable 12, and the substrate 11 is fixed by a spindle motor, for example, by the CAV method.
To rotate. At this time, the objective lens 15 and the mirror 1
6 is moved in the radial direction of the substrate 11 and the laser spot Ls is focused on the photoresist film 17 by the objective lens 15.
Are moved in one direction along the diameter of the substrate 11.

In this case, as shown in FIG. 7, the movement pitch d of the laser spot Ls is set so as not to move more than the diameter D of the laser spot Ls while the turntable 12 makes one rotation. For example, when using a spot Ls whose diameter D is 0.4 μm, the spot Ls is
0.3 in the radial direction of the substrate 11 per turntable rotation
Be prepared to send about μm.

On the other hand, the laser beam L is turned on / off by the AOM 14 in synchronization with the rotation of the turntable 12. Then, the laser beam L is irradiated onto the photoresist film 17 each time the turntable 12 rotates 1 / n, so that the photoresist film 17 has a radial pattern continuous in the radial direction of the substrate 11. Clock mark Mc,
Resist latent images of the unique patterns Pu and the gap patterns GP1 (not shown) and GP2 in the gap areas Zg1 (not shown) and Zg2 are formed.

In the subsequent work, after the photoresist film 17 on the substrate 11 is developed, the remaining photoresist film 1 is formed.
A metal film is vapor-deposited on the entire surface including 7 to produce a master. Then, a mother and a stamper are duplicated from this master, and a disk made of synthetic resin (see the transparent substrate 2 shown in FIG. 5) is molded from this stamper.

Thereafter, the disk 2 is replaced with the magnetic disk 1
When used as a disc, as shown in FIG.
Medium, mark (Mc, Ms) and pattern (GP1, GP
The magnetic film 33 is formed on the surface on which the (2, Pu) etc. are formed, and as shown in the figure, the magnetic film 33a in the convex portion and the magnetic film 33b in the concave portion are magnetized by reversing the magnetization directions. As a method of magnetizing in this way, the magnetic films 33a and 33b of the convex and concave portions are first magnetized with a head that has been supplied with a current of level Ib, and then a current of level -Iu (Ib> Iu) is supplied. Magnetic film 3 on the convex part of the head
It suffices to magnetize 3a in the opposite direction.

Alternatively, first, the magnetic films 33a and 33b of the convex and concave portions are magnetized in a state where the rotation of the disk 2 is slowed down and the flying height of the head is reduced, and then the disk 2
The magnetic field 33a of the convex portion may be magnetized in the direction opposite to the initial direction by increasing the speed of rotation of the head to increase the flying height of the head.

In addition to the above example, as shown in FIG. 5B, a so-called guard band GB may be provided by providing a step between adjacent recording tracks 32. Also in this case, it can be manufactured in the same manner as the above example.

In the example shown in FIG. 5 above, the case where the disc 2 itself is provided with irregularities is shown. However, as shown in FIG. 8, the disc 2 itself is not provided with irregularities and is formed on the disc 2. By selectively removing the magnetic film 33 by etching, the mark (Mc, Ms) and the pattern (G
P1, GP2, Pu) and the recording track 32 may be formed.

As in the case shown in FIG. 5B, the magnetic film 33 between the adjacent recording tracks 32 may be removed to provide a so-called guard band GB (FIG. 8).
(See B). In these examples, the magnetic film 33 may be magnetized in one direction by a head in which a DC current is passed.

Next, a method of manufacturing the magnetic disk 1 shown in FIG. 8 will be described with reference to FIGS. 9 and 10.

First, as shown in FIG. 9A, the glass substrate 4
A mask master disc 44 in which a chrome layer 42 and a photoresist film 43 are sequentially laminated on 1 is prepared. Then, as shown in FIG.
By performing an exposure process using the laser cutting apparatus shown in (1), a resist latent image having a pattern (simply referred to as a recess pattern) corresponding to the recess is formed on the photoresist film 43.

After that, as shown in FIG. 9B, the photoresist film 43 is developed to dissolve the portion of the photoresist film 43 which is irradiated with the laser beam L, whereby the photoresist film 43 is melted.
An opening 45 having a shape of the concave pattern is formed in the. After that, as shown in FIG. 9C, for example, wet etching is performed to remove the chromium layer 42 exposed from the opening 45 by etching. After that, the upper photoresist film 4
3 is peeled off to form the mask 4 by the chrome layer 42.
6 is completed.

Next, as shown in FIG. 10A, the disc 2
A magnetic disk master 48 having a magnetic film 33 and a photoresist film 47 sequentially stacked thereon is prepared. After that, a mask 46 is arranged on the photoresist film 47, and exposure is performed by the proximity method to form a resist latent image having a concave pattern on the photoresist film 47.

Thereafter, as shown in FIG. 10B, the photoresist film 47 is developed to dissolve the portion of the photoresist film 47 irradiated with the laser beam L, whereby the photoresist film 4 is formed.
An opening 49 is formed in 7 along the shape of the recess pattern.
After that, as shown in FIG. 10C, for example, wet etching is performed to remove the magnetic film 33 exposed from the opening 49 by etching. Then, the upper photoresist film 47 is peeled off to complete the magnetic disk 1 shown in FIG.

Next, the operation of the recording / reproducing apparatus according to this embodiment, particularly the read operation of the magnetic disk will be described. First, the servo marks M arranged on both sides of the track center Tc of the magnetic disk 1 by the magnetic head.
Tracking of the magnetic disk 1 is controlled by comparing the reproduction output of s. Also, the system clock signal can be obtained by multiplying the clock pulse obtained each time the magnetic head passes over the clock mark Mc.

FIG. 11 is a block diagram for obtaining the system clock signal. The reproduction output supplied through the reproducing head is first converted into an electric signal by the head amplifier 51 and then amplified. The servo mark Ms
The output fluctuation due to the clock mark Mc is recognized as a servo pulse and a clock pulse. In addition, in the sector where the unique pattern Pu exists, in addition to the above pulse, the unique pattern Pu and the gap pattern GP
The output fluctuations due to 1 and GP2 are recognized as a unique pulse and a gap pulse, respectively.

Next, the peak detection circuit 52 detects the peak of each pulse. These pulses are also input to the unique pattern detection circuit 53. By the way, since the unique pattern Pu is for knowing the absolute position in the circumferential direction of the disk immediately after the disk is started, the PLL as the multiplication means is not locked.
Therefore, the unique pattern Pu must be detected without knowing the frequency or phase of the reproduction signal.

Therefore, sampling is performed asynchronously with the reproduction signal at a sample rate having a frequency close to the clock rate, and the waveform of the reproduction signal substantially matches the reproduction waveform of the unique pattern Pu recorded in advance. This is regarded as the detection of the unique pattern Pu.

For example, in magnetic recording, as shown in FIG. 2, when the reproduction signal is digitally converted, the portion where the magnetization reversal occurs (the peak point of the reproduction signal) is logically set to "1". In many cases, digital data is logically assigned to "0" when there is nothing. The unique pattern Pu has a relatively long length of “0” (0 run).
Since a pattern with a long length) is used, for example, “1100000000001” is used in accordance with the above allocation rule.
A pattern of "1", that is, data in which 10 "0" s are arranged between "11" s at both ends is used.

Further, the unique pattern detection circuit 53 is
As shown in FIG. 12, the reproduction signal is supplied to the clock generation circuit 54.
The binarization circuit 55 that binarizes and outputs the binarized data based on the detection clock from the, and the binarized data that is output to the series from the binarization circuit 55 is supplied and output as digital reproduction pattern data, and The clock generation circuit 5
4, a shift register for performing a bit shift based on the detection clock from 4, a pattern generation circuit 57 for outputting certain predetermined reference pattern data, and the shift register 5
Reproduction pattern data from 6 and a pattern generation circuit 57
And a comparison circuit 58 which outputs a detection signal when the respective pattern data match each other.

By the way, in the binarization circuit 55,
When converting a reproduction signal to binary data, since the reproduction signal is processed by an asynchronous clock, the number of “0” s sandwiched between “1” s may increase by one,
It may decrease, or the number of "1" s at both ends may become one or three.

For example, when the output timing of the detection clock from the clock generation circuit 54 is slightly earlier, the binarized data is "1100000000011" (data in which nine "0s" are arranged between "11" s at both ends). Or when the output timing is a little late, "110
000000000011 ”(data in which 11“ 0s ”are arranged between“ 11s ”at both ends). Also, similarly,
"11000000000 1 11" or (data replacement bit indicated by underline from "0" to "1"), "110 000 000 000 0 1" (bit indicated by underline is replaced with "0" from "1" There can be patterns such as (data).

However, the reproduced data of the unique pattern Pu is basically data in which at least eight "0" s are arranged between "1" and "1", and this unique pattern Pu is detected. First, the data of 10 bits from the most significant bit (that is, the upper 10 bits) is "1.
It is sufficient that "100000000" and "1" exists in the lower 4 bits.

Therefore, this unique pattern detection circuit 5
3, the pattern generating circuit 57 generates predetermined pattern data of, for example, 10 bits, in this example, "11000000", and outputs the lower 4 bits of data of the shift register 56 to the OR circuit 59.
Further, the output of the OR circuit 59 and the output from the comparison circuit 58 are input to the AND circuit 60 in the subsequent stage.

Then, in the comparison circuit 58, the upper 10 bits of the shift register 56 and the pattern generation circuit 5 are
The 10-bit data from 7 is compared, and if the comparison result is the same, a high level signal is output from the output terminal. That is, it is not determined whether "1" exists in the lower 4 bits only when the upper 10 bits of data match, and when both conditions are satisfied, the 14 bits of data supplied to the shift register 56 are unique patterns Pu. Will be detected.

As described above, in the case of the unique pattern detection circuit 53, first, the 10-bit data from the pattern generation circuit 57 is compared with the high-order 10-bit data of the shift register. Of 4
Since the unique pattern Pu is detected by detecting whether or not "1" is present in the bit, it is possible to reliably distinguish the unique pattern Pu from the gap patterns GP1 and GP2.

That is, the logical codes of the gap patterns GP1 and GP2 are "10101010101010" in this example.
101 ”is taken as an example, but in this case as well, since detection is performed asynchronously, for example,“ 101010 0 1010101010 ”
1 ”(data with many underlined bits“ 0 ”inserted) or“ 10101010 1 1010101 ”
(Data in which many bits “1” indicated by underline are inserted) and “1010 0 0 0 0 0 0 10101” (data in which bits underlined are replaced by “0” to “1”) are possible.

However, first, "1100000000"
Gap pattern GP for comparison with the above data.
Even if the data of 1 and GP2 are variously modified as described above, it can be surely discriminated from the data of the unique pattern Pu, and the gap patterns GP1 and GP2 are
Is not mistaken for the unique pattern Pu.

Then, as shown in FIG.
The high level output of the signal from the circuit 60 corresponds to the bit transfer time of the shift register 56, that is, the clock generation circuit 5
It continues for the pulse period of the detection clock from 4 and after that,
It becomes a low level signal until the unique pattern Pu is detected again. That is, the AND circuit 60 outputs a pulse signal having a pulse width that rises based on the detection of the unique pattern Pu and has a pulse width corresponding to the bit transfer time of the shift register 56.

Further, as shown in FIG. 11, a clock window creating circuit 61 is connected to the subsequent stage of the unique pattern detecting circuit 53. This creating circuit 61
A programmable counter is incorporated therein, and a clock count value from the detection of the unique pattern Pu to the next clock mark Mc is registered as an initial value in this counter. Then, the counter starts operating based on the supply of the pulse signal from the AND circuit 60 in the unique pattern detection circuit 53,
Every time a detection clock is input from the clock generation circuit 54, the count value in the counter is updated by subtraction. Then, when the count value in the counter becomes zero, a window pulse is output.

This window pulse is applied to the clock pulse extraction circuit 6 connected to the subsequent stage of the peak detection circuit 52.
2 is supplied. This clock pulse extraction circuit 62
For example, it is constituted by an AND circuit, and the logical product of the peak detection waveform from the peak detection circuit 52 and the window pulse from the clock window creation circuit is taken to extract the clock pulse based on the reproduction of the clock mark Mc.

The clock pit pulse extracted by the clock pulse extraction circuit 62 is supplied to a multiplying means (PLL) 63 at the subsequent stage, multiplied by this multiplying means 63, and a system clock signal (servo clock,
Data clock).

In particular, in this embodiment, the clock mark Mc, the unique pattern Pu, and the gap patterns GP1 and GP2 are formed as a radial strip-shaped pattern (see FIG. 1) continuous in the radial direction of the magnetic disk 1. Therefore, when the magnetic head is at the track center and when the magnetic head is off the track center and is in a so-called off-track state, the clock mark Mc,
Unique pattern Pu and gap patterns GP1 and G
P2 is detected.

From this, the clock mark Mc, the unique pattern Pu, and the gap patterns GP1 and GP2.
Can always be read with a high S / N, and in particular, since the clock pulse can be obtained with a high S / N from the clock mark Mc, a system clock signal with a small jitter component can be obtained. Further, since the amplitude of the clock pulse does not change even when the magnetic head is off-track, a clock pulse with good S / N can be obtained even during the seek operation of the head.

Embodiment 2 Next, an embodiment in which the recording / reproducing medium according to the present invention is applied to a sample servo type optical disk will be described with reference to FIG. Since the entire track format of the optical disc 31 according to this embodiment is the same as that of the magnetic disc 1 described in the first embodiment, detailed description thereof will be omitted, but this optical disc 31 also has the same track format as shown in FIG. Similarly to the magnetic disk 1, the clock mark M
c, the unique pattern Pu, and the gap patterns GP1 and GP2 are formed in a substantially radial pattern continuous in the radial direction of the optical disc 31.

As shown in FIG. 2, each mark (Ms, Mc) and each pattern (Pu, GP1, GP2) has a concave portion 3 formed in the transparent substrate 2 at the time of molding, and a reflective film is formed thereon. 4 is formed into a film, so that when viewed from the transparent substrate 2 side, a substantially circular or rectangular convex portion (servo mark M
s) and strip-shaped convex portions (clock mark Mc, unique pattern Pu, gap patterns GP1 and GP2). In FIG. 14, the unique pattern Pu and the gap patterns GP1 and GP2 are shown.
Is not shown.

This optical disk 31 is manufactured by the steps of exposing and developing with the laser cutting device shown in FIG. 6 to prepare a master, and then duplicating the mother and stamper based on this master, and using this stamper to make synthetic resin. The manufactured disk 2 is molded. And in disk 2,
The optical disk 31 according to the present embodiment is completed by depositing the reflection film 4 of aluminum or the like on the surface on which the clock marks Mc and the like are formed.

The recording / reproducing apparatus for the optical disc 31 has the same structure as that shown in FIG. 11 except that it is an optical pickup instead of a magnetic head (not shown), and therefore its explanation is omitted. Also in this case, since the clock mark Mc, the unique pattern Pu, and the gap patterns GP1 and GP2 are formed as a radial strip pattern (see FIG. 1) continuous in the radial direction of the optical disc 1, the clock mark Mc, the unique pattern Pu, and the The gap patterns GP1 and GP2 can be always read out with a high S / N, and in particular, the clock pulse can be obtained with a high S / N from the clock mark Mc, and the system clock signal with less jitter component can be obtained. . Also, since the amplitude of the clock pulse does not change even when the beam spot from the optical pickup is off-track, a clock pulse with good S / N can be obtained even during the seek operation.

When the manufactured disk is used as the optical disk 31, the gap patterns GP1 and GP2 thus formed have information transferred by a reflective film such as aluminum, and therefore, are partially erased by recording / reproducing data. There is no inconvenience. Therefore, when the signal is reproduced by the optical pickup, a predetermined signal can be obtained without fail from the formed gap areas Zg1 and Zg2.

However, when the manufactured disk is used as the magnetic disk 1, there is a risk that a part of the information magnetized in advance in the gap portion will be erased by the magnetic head.

Therefore, in the present embodiment, signal processing at the time of switching from recording of information in the data area Zd to reproduction of information in the servo area Zs and reproduction of information in the servo area Zs to recording of information in the data area Zd. By performing the signal processing at the time of switching of the above, the partial erasing of information in the gap areas Zg1 and Zg2 by the magnetic head is eliminated.

That is, first, signal processing at the time of switching from recording of information in the data area Zd to reproduction of information in the servo area Zs will be described with reference to FIG. First, at the time when the magnetic head reaches the rear end portion of the data area Zd (the beginning portion of the gap area Zg1), that is, at t1, the write enable signal Sew supplied to the recording amplifier is turned off to disable the recording amplifier. When the recording current Iw is cut off by setting the (transmission impossible) state, at the same time, the read enable signal Ser supplied to the reproduction amplifier is turned on to enable the reproduction amplifier (transmittable) state.

At this time, in the process of cutting off the recording current Iw, the magnetization information corresponding to the residual recording current dIw flowing at that time is newly recorded at the head portion of the gap area Zg1. However, the gap area Zg
Since the magnetic film 33 forming the gap pattern GP1 formed in No. 1 is magnetized in a single direction as shown in FIGS. 5 and 8, when the magnetic head passes over the gap area Zg1. If the polarity of the recording current Iw is selected so that a magnetic field in the same direction as the direction of magnetization recorded in the gap area Zg1 is generated from the magnetic head, recording of information in the data area Zd to information in the servo area Zs will be performed. There is no problem that the magnetization information in the gap area Zg1 is rewritten when the reproduction is switched. That is, the gap area Z in advance
It is avoided that the information recorded in g1 is erased by switching from recording to reproduction.

Further, correct data reproduction is not performed during the time until the reproduction amplifier starts up (for that reason, the gap area Zg1 is provided). But,
Since the unique pattern Pu is not detected (searched) during data recording, the gap pattern Zg1
There is no harm caused by not being played.

Next, the signal processing at the time of switching from the reproduction of information in the servo area Zs to the recording of information in the data area Zd will be described with reference to FIG. First, at the time when the magnetic head reaches the rear end portion of the servo area Zs (the head portion of the gap area Zg2), that is, at t2, the read enable signal Sew supplied to the reproducing amplifier is turned off to disable the reproducing amplifier. At the same time as the (transmission impossible) state, the write enable signal Sew supplied to the recording amplifier is turned on to enable the recording amplifier (transmission possible) state to prepare for data recording.

Also in this case, the gap area Zg
The gap pattern GP2 in the last part of 2 is magnetized in accordance with the transient current iw of the new recording current to be recorded. That is, new magnetization information is overwritten. However, similar to the above, when the magnetic head passes over the gap area Zg2, a magnetic field in the same direction as the direction of magnetization recorded in the gap area Zg2 is generated from the magnetic head so that the recording current Iw If you select the polarity, the gap area Z
The problem that the magnetization information of g2 is rewritten does not occur.

As described above, according to the magnetic disk 1 and the optical disk 31 of this embodiment, the unique pattern Pu is used.
Is a pattern having a large 0 run length such that logically "0" continues for a long time, and the gap patterns GP1 and GP are
Since 2 is a pattern in which 0 run length is limited so that “0” is not logically continued, the unique pattern Pu
And the reproduction signals of the gap patterns PG1 and PG2 have completely different signal waveforms. Therefore, the unique pattern detection circuit 53 in the subsequent stage is prevented from erroneously detecting the gap patterns GP1 and GP2 as the unique patterns Pu, and the detection performance of the unique patterns Pu can be improved. As a result, the position of the clock mark Mc in the circumferential direction can be accurately determined,
The operational reliability of the recording / reproducing apparatus can be improved.

Further, according to the recording / reproducing apparatus in the present embodiment, the code of the unique pattern Pu is, for example, "11000".
When the code of the gap patterns GP1 and GP2 is a code followed by “1” or a code in which “1” and “0” are alternately arranged, data obtained by encoding the reproduction signal from the head amplifier 51. Higher-order, for example, 10-bit data is given pattern data (“1
100000000 ") and detects whether at least" 1 "exists in lower 4-bit data, for example, and the comparison result is the same, and lower data is" 1 ".
The unique pattern detection circuit 53 that recognizes the unique pattern Pu as the unique pattern Pu is provided for the first time.
It is possible to surely detect without mistakenly as G1 and PG2.

Further, when the disk is applied to the magnetic disk 1, when the recording of the information signal by the magnetic head is switched to the reproduction, the residual recording current d from the magnetic head is changed.
Iw causes a problem that the magnetization information recorded in the gap area Zg1 is destroyed. However, when the magnetic head passes over the gap area Zg1 when switching from recording of an information signal by the magnetic head to reproduction. The polarity of the recording current immediately before switching the current applied to the recording current from the recording current to the reproducing current is selected so as to generate a magnetic field in the same direction as the magnetization direction of the signal recorded in the gap area Zg1. Recording current d
The inconvenience that the magnetization information in the gap area Zg1 is destroyed by Iw does not occur.

Further, when switching from reproduction of an information signal by the magnetic head to recording, the recording information iw in the transient period from the magnetic head causes a problem that the magnetization information recorded in the gap area Zg2 is destroyed. When switching from reproducing the information signal by the head to recording, when the magnetic head passes the rear end of the servo area Zs, the polarity of the recording current immediately after switching the current applied to the magnetic head from the reproducing current to the recording current is Since the magnetic field is selected so as to be generated in the same direction as the magnetization direction of the signal recorded in the gap area Zg2, the gap current Zw is changed by the recording current iw in the transition period.
The inconvenience that the magnetization information of g2 is destroyed does not occur.

In the first and second embodiments, the clock mark, the unique pattern, and the gap pattern are formed as a substantially radial pattern continuous in the radial direction of the disk. However, of course, a rectangular or circular shape is possible. It may be formed in a pit shape.

[0095]

As described above, according to the recording / reproducing medium of the present invention, the servo area in which the head positioning signal is recorded on the same surface, the data area for recording / reproducing the data signal, and the servo area are provided. In the recording / reproducing medium having the cap area between the data area and the data area, a unique pattern indicating at least the position in the circumferential direction is provided, and a signal different from the unique pattern is recorded in the gap area in advance. Therefore, it is possible to easily detect the unique pattern and the gap without erroneous detection, and it is possible to avoid the inconvenience of erroneously detecting the unique pattern and the gap.

Further, according to the present invention, a servo area in which a head positioning signal is recorded on the same surface, a data area for recording / reproducing a data signal, and a cap area between the servo area and the data area are provided. In a recording / reproducing method for recording / reproducing information signals on / from a recording medium with a magnetic head, a unique pattern indicating at least a circumferential position is provided on the magnetic recording / reproducing medium, and a signal different from the unique pattern is provided in a gap region. Is recorded in advance. When switching from recording of an information signal by the magnetic head to reproduction, when the magnetic head passes the rear end of the data area, the current applied to the magnetic head is switched from the recording current to the reproduction current, and the recording just before the switching is performed. Since the polarity of the current is selected so as to generate a magnetic field in the same direction as the magnetization direction of the signal recorded in the gap area, when the recording / reproducing medium is a magnetic disk, the recording of the information signal by the magnetic head is performed. When switching to reproduction, it is possible to avoid the inconvenience that the magnetization information recorded in the gap is destroyed by the residual recording current from the magnetic head.

In the recording / reproducing method of the present invention, the magnetic recording / reproducing medium is provided with a unique pattern indicating at least a position in the circumferential direction, and a signal different from the unique pattern is recorded in the gap area in advance. Then, when switching from reproduction of the information signal by the magnetic head to recording, when the magnetic head passes the rear end of the servo area,
The current applied to the magnetic head is switched from the reproducing current to the recording current, and the polarity of the recording current immediately after the switching is
When the recording / reproducing medium is a magnetic disk, when switching from reproduction of an information signal by the magnetic head to recording, the magnetic field is selected to generate a magnetic field in the same direction as the magnetization direction of the signal recorded in the gap area. It is possible to avoid the disadvantage that the magnetization information recorded in the gap is destroyed by the recording current from the magnetic head during the transition period.

Further, according to the present invention, a servo area in which a head positioning signal is recorded on the same surface, a data area for recording / reproducing a data signal, and a cap area provided between the servo area and the data area. In a recording / reproducing apparatus for recording and reproducing an information signal to / from a recording / reproducing medium having a disc, a unique pattern indicating at least a circumferential position is provided on the recording / reproducing medium, and a signal different from the unique pattern is previously provided in the gap area. Record. Since the recording / reproducing apparatus is provided with means for detecting the unique pattern by distinguishing it from the gap area, the unique pattern can be easily and accurately detected by distinguishing it from the gap.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a track format of an embodiment (hereinafter simply referred to as a magnetic disk according to an embodiment) in which a recording / reproducing medium according to the present invention is applied to a magnetic disk of a sample servo system.

2A and 2B are explanatory views showing a unique pattern formed in a unique area of the magnetic disk according to the present embodiment. FIG. 2A shows a shape of the unique pattern, and FIG. 2B shows a reproduced signal waveform of the unique pattern. C of the same figure shows logical data of a reproduction signal of a unique pattern.

3A and 3B are explanatory diagrams showing an example of a gap pattern formed in a gap area of the magnetic disk according to the present embodiment. FIG. 3A shows a shape of the gap pattern, and FIG. 3B shows a reproduced signal waveform of the gap pattern. FIG. 13C shows the logical data of the reproduction signal of the gap pattern.

FIG. 4 is an explanatory diagram showing another example of the gap pattern formed in the gap area of the magnetic disk according to the present embodiment, FIG. 4A showing the shape of the gap pattern, and FIG.
Shows the reproduced signal waveform of the gap pattern, and FIG. 13C shows the logical data of the reproduced signal of the gap pattern.

5 is a cross-sectional view of a magnetic disk according to the present embodiment, a magnetic disk in which a magnetic film is formed on a substrate having irregularities formed on the surface thereof, and FIG. 5A is a line AA in FIG. A sectional view and FIG. 2B are sectional views taken along the line BB in FIG.

FIG. 6 is a configuration diagram showing an optical recording device (laser cutting device) used for manufacturing a master of a magnetic disk according to the present embodiment.

FIG. 7 is a schematic diagram showing movement control of a beam spot in a laser cutting device.

8 is a cross-sectional view of a magnetic disk according to the present embodiment, particularly a magnetic disk in which a magnetic film is selectively formed on a substrate, and FIG. 8A is a cross-sectional view taken along the line AA in FIG.
FIG. 2B is a sectional view taken along the line BB in FIG.

9A and 9B are process flow charts showing an example of a method for manufacturing the magnetic disk shown in FIG. 8, FIG. 9A shows an exposure process when forming a mask, and FIG. 9B is a development process when forming a mask. C shows the completion stage of the mask.

10 is a process flow chart showing an example of a method of manufacturing a magnetic disk following FIG. 9, wherein FIG. 10A shows an exposure process when forming a magnetic disk using a mask, and FIG. The developing process at the time of formation is shown, and FIG. 7C shows the completion stage of the magnetic disk.

FIG. 11 is a block diagram showing a magnetic disk to which the recording / reproducing apparatus according to the present invention is applied, and particularly a circuit configuration for obtaining a system clock signal from the magnetic disk according to the present embodiment.

FIG. 12 is a block diagram showing a circuit configuration of a unique pattern detection circuit incorporated in the recording / reproducing apparatus in the example.

FIG. 13 is a schematic diagram showing a track format of an embodiment (hereinafter, simply referred to as an optical disk according to an embodiment) in which the recording / reproducing medium according to the present invention is applied to an optical disk of a sample servo system.

FIG. 14 is a sectional view showing a sectional shape of the optical disc in the example.

FIG. 15 is a timing chart showing signal processing when switching from recording of information in the data area to reproduction of information in the servo area in the recording / reproducing apparatus in the example.

FIG. 16 is a timing chart showing signal processing at the time of switching from reproduction of information in the servo area to recording of information in the data area in the recording / reproducing apparatus in the example.

FIG. 17 is a schematic diagram showing a track format of a magnetic disk of a sample servo system according to a conventional example.

FIG. 18 is a schematic diagram showing a track format of a magnetic disk of a sample servo system according to another conventional example.

[Explanation of symbols]

 1 --- Magnetic disk 31 --- Optical disk Zd --- Data area Zs --- Servo area Zu ---・ ・ ・ Unique area Zg1, Zg2 ・ ・ ・ Gap area Mc ・ ・ ・ ・ ・ ・ Clock mark Ms ・ ・ ・ ・ ・ ・ Servo mark Pu ・ ・ ・ ・ ・ ・ Unique pattern GP1, GP2 ・..Gap pattern 2 ......... Transparent substrate (disk) 32 ........ Recording track 33 ........ Magnetic film 11.・ Substrate 12 ・ ・ ・ ・ ・ ・ Turntable 13 ・ ・ ・ ・ ・ ・ Gas laser light source 14 ・ ・ ・ ・ ・ ・ AOM 15 ・ ・ ・ ・ ・ ・ Objective lens 16 ・ ・ ・・ ・ ・ Mirror 17 ・ ・ ・ ・ ・ ・ ・ ・ Photoresist film 18 ・ ・ ・・ ・ ・ ・ Ultrasonic generator 19 ・ ・ ・ ・ ・ ・ Pattern generator 20 ・ ・ ・ ・ ・ ・ PLL 21 ・ ・ ・ ・ ・ ・ Rotary encoder 51 ・ ・ ・ ・ ・ ・Head amplifier 52 ... Peak detection circuit 53 ... Unique pattern detection circuit 54 ... Clock generation circuit 55 ... Binary Circuit 56 ..... shift register 57 ..... pattern generation circuit 58 ..... comparison circuit 61 ..... clock window creation circuit 62.・ ・ ・ ・ ・ ・ ・ ・ Clock pulse extraction circuit 63 ・ ・ ・ ・ ・ ・ PLL

Claims (6)

[Claims] 1. A recording / reproducing medium having a servo area in which a head positioning signal is recorded on the same surface, a data area for recording / reproducing a data signal, and a cap area between the servo area and the data area, A recording / reproducing medium having a unique pattern indicating at least a position in the circumferential direction, and a signal different from the unique pattern being previously recorded in the gap region. 2. The signal recorded in the gap area comprises:
The recording / reproducing medium according to claim 1, wherein all are signals that logically indicate "1". 3. The signal recorded in the gap area comprises:
The recording / reproducing medium according to claim 1, wherein the recording / reproducing medium is a signal that logically represents "1" and "0" alternately. 4. A magnetic recording medium having a servo area in which a head positioning signal is recorded on the same surface, a data area for recording and reproducing a data signal, and a cap area between the servo area and the data area. In the recording / reproducing method for recording / reproducing an information signal with a magnetic head, the magnetic recording / reproducing medium has a unique pattern indicating at least a position in the circumferential direction, and a signal different from the unique pattern is present in the gap region. Pre-recorded, when switching from recording of an information signal by the magnetic head to reproduction, when the magnetic head passes the rear end of the data area, a current applied to the magnetic head is changed from a recording current to a reproduction current. The polarity of the recording current immediately before the switching is the same as the magnetization direction of the signal recorded in the gap area. A recording / reproducing method characterized by being selected so as to generate a magnetic field in one direction. 5. A recording / reproducing method for recording / reproducing an information signal on / from a magnetic recording medium having a servo area in which a head positioning signal is recorded on the same surface and a data area for recording / reproducing a data signal. In the method, the magnetic recording / reproducing medium has a unique pattern indicating at least a position in the circumferential direction, and a signal different from the unique pattern is recorded in advance in the gap area, and When switching from reproduction to recording, when the magnetic head passes the rear end of the servo area, the current applied to the magnetic head is switched from the reproduction current to the recording current, and the polarity of the recording current immediately after the switching. Are selected to generate a magnetic field in the same direction as the magnetization direction of the signal recorded in the gap region. Recording and playback method. 6. A recording / reproducing device having a servo area in which a head positioning signal is recorded on the same surface, a data area for recording / reproducing a data signal, and a cap area provided between the servo area and the data area. In a recording / reproducing apparatus for recording / reproducing an information signal to / from a medium, the recording / reproducing medium has a unique pattern indicating at least a position in the circumferential direction, and a signal different from the unique pattern is previously stored in the gap region. A recording / reproducing apparatus, which is configured to be recorded and provided with means for detecting the unique pattern by distinguishing it from the gap area.