JP3121159B2 - Recording and reproducing method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing method and an apparatus therefor, and more particularly to a recording / reproducing method and an apparatus using the principle of a scanning tunnel microscope or the principle of an atomic force microscope.

[0002]

2. Description of the Related Art Various methods have been conventionally known as a high-density recording / reproducing method. Representative methods include a recording / reproducing method using magnetism and a recording / reproducing method using light. is there. However, in the recording / reproducing method using magnetism,
Due to restrictions on devices such as a magnetic head used for recording and reproduction, the recording wavelength is limited to about 1 μm. Also,
In the recording / reproducing method using light, the recording wavelength is limited to about 1 to 0.5 μm from the beam diameter of the light used for recording / reproducing.

On the other hand, in recent years, a scanning tunneling microscope (STM) capable of analyzing a surface state of a solid with high resolution having a horizontal resolution of several Å or less and a vertical resolution of 1 Å or less has been developed (G. Binnig et al. , Helvetica Physica Acta, 5
5, 726, 1982), a recording / reproducing method for recording / reproducing irregularities or changes in electronic state on the recording medium surface in the order of nm using the principle of a scanning tunneling microscope is disclosed in US Pat.
No. 75822, JP-A-63-161552 and JP-A-63-161553. Conventional recording / reproducing methods utilizing the principle of such a scanning tunneling microscope include, for example, forming a tracking groove by irradiating a flat recording medium having a conductive layer on its surface with an ion beam of high energy and etching the recording medium. At the same time, the intensity of the ion beam is modulated in accordance with the recording signal to form a depression, thereby forming a recording bit, and then reproducing the recording signal using the principle of a scanning tunneling microscope to obtain about 50 Gbit / cm. ^{A device} which performs high-density recording and reproduction of ² has been proposed (Japanese Patent Laid-Open No. 1-151035).

Further, an atomic force microscope (AFM) to which the technology of a scanning tunneling microscope is applied has been developed (G. Binnig et al.
t al., Phy. Rev. Lett., 56, 930, 1986), and it is possible to obtain information on the unevenness of the surface of the recording medium.
A recording / reproducing apparatus applying the principle of such an atomic force microscope is disclosed in JP-A-1-245445.

[0005]

In a recording / reproducing apparatus to which the above-mentioned principle of the scanning tunneling microscope is applied, a recording bit formed on a recording medium is extremely small, and a tracking method corresponding to this is always a concern. And
The following tracking method has been proposed. (1) A tracking method in which a recording medium is processed by some means (for example, a linear groove is formed on the recording medium), and the processed part is used as a tracking marker. (2) A tracking method in which an atomic arrangement of a recording medium substrate is directly detected as a tracking signal. (3) A tracking method for performing tracking by wobbling the probe electrode when the probe electrode scans a recording bit formed on a recording medium.

However, the above-described tracking methods (1) and (2) have a problem that a great restriction is imposed on the recording medium. That is, in order to process a recording medium, the recording medium must be able to withstand the processing process, and the processing shape must be extremely high. Further, if an attempt is made to utilize the atomic arrangement of the substrate, the substrate is limited to a crystalline substrate. On the other hand, the tracking method of the above (3) requires a mechanism for periodically controlling the scanning of the probe in a direction perpendicular to the recording bit string, and has a problem that the entire apparatus becomes complicated.

An object of the present invention is to provide a recording / reproducing method and apparatus capable of performing tracking without forming a tracking groove or wobbling by processing a recording medium.

[0008]

According to the recording / reproducing method of the present invention, a probe is relatively scanned along a recording medium on which two or more types of state changes can be formed in addition to a non-recording state. Record information at a predetermined location
By applying a pulse voltage between the probe and the recording medium according to a digital signal on which tracking information of a predetermined period is superimposed, two types of information are recorded on the recording medium.
Forming a bit ; and detecting a signal due to physical interaction between the probe and the recording medium while relatively scanning the probe along the recording medium on which the information bits are formed; and detects the tracking information from the detected signal, and a step of performing tracking according to the tracking information, the track
The period of the king information is longer than the interval of the information bits.
And adjacent to any track on the recording medium
Different between the two tracks.

[0009]

Further, the signal due to the physical interaction is
From the tunnel current flowing between the probe and the recording medium.
It may be detected.

Further , the signal due to the physical interaction is
Detected from the atomic force acting between the probe and the recording medium.
You may.

[0012] The recording / reproducing apparatus according to the present invention comprises the recording / reproducing method.
It is characterized by performing recording and reproduction using a method.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

According to the recording / reproducing method of the present invention, the method other than the non-recording state includes
By using a recording medium capable of forming more than one type of state change and applying a pulse voltage between the recording medium and the probe in accordance with a signal obtained by superimposing the tracking information on the recording information, the recording information and the tracking information are applied. Since it is possible to form a recording bit string including on the recording medium,
Only the tracking information is extracted from the tunnel current including the recording information and the tracking information, and the tracking control information (for example,
The direction and amount of deviation of the probe from the recording bit string)
Can be detected.

Further, the recording / reproducing method of the present invention uses a recording medium capable of forming one or more types of state changes other than the non-recording state, and superimposes tracking information on recording information between the recording medium and the probe. By applying a pulse voltage according to the applied signal, it is possible to form a recording bit string including the tracking information together with the recording information on the recording medium, so that only the tracking information is obtained from the displacement of the probe including the recording information and the tracking information. And the tracking control information necessary for the tracking control of the probe can be detected.

In the recording / reproducing apparatus according to the present invention, the information recording means may include a pulse corresponding to a signal in which tracking information is superimposed on recording information on a recording medium on which at least one type of state change other than a non-recording state can be formed. By applying a voltage between the probe and the recording medium, a recording bit string is formed, recording information and tracking information are recorded on the recording medium, and the tracking control information detecting means is detected by the tunnel current detecting means. The tracking information recorded on the recording medium is reproduced from the tunnel current, the tracking control information necessary for the tracking control of the probe is detected from the reproduced tracking information, and the scanning control means is detected by the tracking control information detecting means. The first recording of the present invention is performed by controlling the probe scanning means in accordance with the tracking control information. It is possible to realize a raw way.

In the recording / reproducing apparatus according to the present invention, the information recording means may be adapted to respond to a signal in which tracking information is superimposed on recording information on a recording medium capable of forming at least one type of state change in addition to a non-recording state. The applied pulse voltage is applied between the probe and the recording medium, thereby forming a recording bit string, recording the recording information and the tracking information on the recording medium, and detecting the tracking control information by the displacement detecting means. The tracking information recorded on the recording medium is reproduced from the displacement obtained, the tracking control information necessary for the tracking control of the probe is detected from the reproduced tracking information, and the scanning control means is detected by the tracking control information detecting means. The second recording / reproducing method of the present invention is controlled by controlling the probe scanning means according to the tracking control information. It can be current.

[0024]

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

FIG. 1 is a block diagram showing a first embodiment of the recording / reproducing apparatus of the present invention.

The recording / reproducing apparatus 10 comprises the following components.

(1) Probe 11 The probe 11 is used when recording information and tracking information are recorded on the recording medium 2 and when reproducing the recording information and tracking information recorded on the recording medium 2. The probe 11 is supported by a cantilever 12 having a Z-direction scanning mechanism 13 attached to the opposite side of the probe 11. The distance between the probe 11 and the recording medium 2, Z direction control circuit 16 to the tunneling voltage V _t which is input from the low-pass filter 15 and a constant value Z
The driving of the direction scanning mechanism 13 in the illustrated Z-axis direction is always kept constant. Incidentally, the low-pass filter 15, the tunnel voltage V _t which is converted from the tunnel current J _t by current-voltage conversion circuit 14 to be described later is input.

(2) Probe Scanning Unit The XY scanning mechanism 17 functions as a probe scanning unit for relatively scanning the probe 11 along the recording medium 2. That is, the substrate 1 on which the recording medium 2 is formed is placed on the XY scanning mechanism 17 and scanned by the XY scanning mechanism 17 in the illustrated X-axis direction and the illustrated Y-axis direction, so that the probe 11 2 are relatively scanned.

(3) Information Recording Means The bias generation circuit 20, the pulse generation circuit 21, and the reference signal generation circuit 22 apply a pulse voltage corresponding to a signal in which tracking information is superimposed on recording information to the probe 11 and the recording medium 2. By applying the voltage between them, a recording bit string is formed on the recording medium 2 and functions as an information recording unit that records the recording information and the tracking information on the recording medium 2. The recording signal S _R indicating the recording information is input from the microcomputer 19 to the pulse generation circuit 21 described later, and the tracking signal T indicating the tracking information is input from the reference signal generation circuit 22 to the pulse generation circuit 21. You. Further, at the time of recording and reproduction, 0.1 to
By applying a bias voltage of about 1 V from the bias circuit 20 between the probe 11 and the recording medium 2, the tunnel current _Jt is set to a set value.

(4) Tunnel Current Detecting Means The current-to-voltage conversion circuit 14 includes the probe 11 and the recording medium 2
Tunnel current J flowing between_t Detect tunnel current
Functions as detection means. Here, the current-voltage conversion circuit 1
4 is a tunnel current J input from the probe 11_t To
Tunnel voltage V _t Convert to

(5) Tracking control information detecting means The band-pass filter 25, the modulation circuit 26, the first and second tuning detection circuits 27 and 28, and the comparator 29
Reproducing the tracking information recorded from the tunnel current J _t detected by the tunnel current detection means to the recording medium 2,
It functions as tracking control information detecting means for detecting tracking control information necessary for tracking control of the probe 11 from the reproduced tracking information. Incidentally, the band pass filter 25, the tunnel voltage V _t which is converted from the tunnel current J _t by current-voltage conversion circuit 14 is input. Moreover, the modulation circuit 26, in addition to the tunnel voltage V _t which has passed through the band-pass filter 25, the reference signal R is input from the reference signal generating circuit 22. Further, the output signals of the modulation circuit 26 are input to the first and second tuning detection circuits 27 and 28, respectively. The output signal of the first tuning detection circuit 27 and the output signal of the second tuning detection circuit 28 are Each is input to the comparator 29.

(6) Scanning control means The microcomputer 19 and the XY scanning control circuit 18 function as scanning control means for controlling the probe scanning means in accordance with the tracking control information detected by the tracking control information detecting means. Here, the XY scanning control circuit 18 controls the XY scanning mechanism 17 in accordance with the XY scanning control signal output from the microcomputer 19 based on the tracking control information, so that the XY scanning control circuit 18 follows the recording bit sequence formed on the recording medium 2. Probe 11
Is scanned correctly.

[0033] (7) a recording information reproducing means high pass filter 23 and the reproduction signal demodulation circuit 24, reproducing and recording information for reproducing the information recorded on the recording medium 2 from the tunnel current detected by the detection means tunnel current J _t Functions as a means. The recording information reproduced is outputted from the reproduction signal demodulation circuit 24 as a reproduced signal S _P. Here, the tunnel voltage V _t converted from the tunnel current J _t by the current-voltage conversion circuit 14 is input to the high-pass filter 23. Further, the reproduction signal demodulation circuit 24, the tunnel voltage V _t that has passed through the high pass filter 23 is inputted.

Next, the recording medium 2 will be described in detail.

The recording medium 2 formed on the substrate 1 is made of a monomolecular film made of, for example, squarylium-bis-6-octylazulene (hereinafter, referred to as "SOAZ") by a Langmuir-Projection method. A material in which two or more types of state changes can be formed in addition to a non-recorded state (that is, two or more types of memory effects). ).

[0036] between the probe 11 and the recording medium 2, a pulse voltage of 6V created by modulating the pulse train is applied from the pulse generating circuit 21, 10nmφ (tunnel current J _t size flows of 10 pA) Are formed on the recording medium 2. Even if the application of the pulse voltage is stopped, the state where the recording bit of 10 nmφ is formed on the recording medium 2 (hereinafter, referred to as “initial state”) is maintained.

[0037] between the recording medium 2 and the probe 11 in the initial state, upon application of a voltage of the voltage and + 1.5V for -8V from the pulse generating circuit 21 in a pulsed manner on state tunnel current flows J _t of 100nA Occurs. This on-state is maintained even when the application of the voltage of −8 V and the voltage of +1.5 V is stopped as in the initial state, but the palace voltage of 5 V is applied between the recording medium 2 and the probe 11. When done
Return to the initial state.

Therefore, by utilizing the initial state, the ON state, and the non-recording state, a recording bit string can be formed on the recording medium 2 by superimposing the tracking information together with the recording information.

FIG. 2 is a diagram schematically showing a method of forming a recording bit string on the recording medium 2 by superimposing tracking information together with recording information.

[0040] As an initial state, each recording bit B _I showing only the recording information is formed on each of the recording medium 2 in the sequence shown in FIG. (A). When the tracking signal T long wavelength shown in (B) is applied onto the recording medium 2, the recording bit B _I of the part tracking signal T is superimposed, respectively, the record information and the tracking information is superimposed Recording bit B _IT (see FIG. 3C). Therefore,
Recording bit sequence shown in FIG. (C), the recording bit B _I showing only the recording information is formed portion (portion of the initial state)
When, made from the recorded information and tracking information and the recording bits B _IT superimposed are formed portion (portion in the ON state), and one of the recording bits is not also formed part (portion of the non-recorded state) Becomes

The tracking signal T is supplied to the reference signal generation circuit 2
After being generated in step 2, the signal is sent to the pulse generation circuit 21.
In the pulse generating circuit 21, a pulse signal (6) corresponding to the recording signal S _R sent from the microcomputer 19 is output.
A pulse voltage) and V, the voltage of the pulse signal corresponding to the recording signal S _R and a tracking signal T (-8 V and +1.5
And a pulse-like voltage composed of a voltage of V) are generated in accordance with an instruction from the microcomputer 19. Here, the tracking signal T has different frequencies in recording bit strings adjacent to each other. That is, the frequency of the tracking signal T is set such that the frequency F _T1 = f,
Frequency F _T2 = f + Δf, frequency F _T3 = f + 3Δf, frequency F _T4 = f + 2Δf, frequency F _T1 = f,.

Next, the reproducing operation of the recording / reproducing apparatus 10 will be described.

At the time of reproduction, the XY scanning mechanism 17
After moving the probe 11 to the desired recording bit sequence,
Tunnel current J flowing between lobe 11 and recording medium 2
_t Detect changes in Detected tunnel current J_t Is
The tunnel voltage V_t Is converted to
You. At this time, the recording bit string shown in FIG.
If it is formed on the medium 2, the current-voltage conversion circuit 1
4 converted tunnel voltage V_t The waveform of FIG. 3 (A)
It becomes as shown in. Therefore, the tunnel voltage V _t Ha
When the tunnel voltage V_t Long wave
By removing the component of the long tracking signal T,
The recording signal S as shown in FIG._R Take only the ingredients
Can be put out. As a result, the high-pass filter 23
Tunnel voltage V_t Into the reproduction signal demodulation circuit 24.
The reproduced signal S_P Can be created
You.

On the other hand, the tunnel voltage V_t The band pass
To the tunnel voltage V _t Short wavelength recording signal
No. S_R 3C by removing the components of
It is possible to extract only the components of the tracking signal T
it can. At this time, the frequency of the tracking signal T is
As mentioned, the frequency F_T1, Frequency F_T2, Frequency F_T3,
Frequency F_T4, Frequency F_T1…… and the adjacent recording bits
The band-pass filter 25
The components of the tracking signal T extracted in
Of the tracking signal T formed in the recording bit string
Number (eg, frequency F_T1And ) But also each other
Are formed in two recording bit strings adjacent to each other.
Frequency F of the tracking signal T_T2, F_T4Also mix
You. Tracking formed on the recording bit string during scanning
Frequency F of the signal T_T1Reference signal R having the same frequency as
And the tracking signal T in the modulation circuit 26
After being adjusted, the output signal of the modulation circuit 26 becomes the first and second signals.
2 to be input to the tuning detection circuits 27 and 28, respectively.
The frequency is F_T2-F_T1= Δf and the first difference signal
Wave number is F_T4-F_T1= 2Δf and the first difference signal
And second tuning detection circuits 27 and 28, respectively.
It is. Note that the first difference signal and the second difference signal are respectively
From the first and second tuning detection circuits 27 and 28
It is output after rectification. Of the first difference signal
The output level and the output level of the second difference signal are compared.
The output level of the first difference signal is compared by the comparator 29.
From the magnitude relationship between the bell and the output level of the second difference signal,
The direction of deviation from the recording bit sequence of the
The output level of the first difference signal and the output level of the second difference signal
Deviation from the recording bit string of the probe 11 due to the difference in bell
Know the amount. Therefore, the output signal of the comparator 29
Scan control circuit via microcomputer 19
18, the displacement direction and the displacement amount
The XY scanning mechanism 17 is controlled according to the
Control can be performed accurately.

FIG. 4 is a block diagram showing a second embodiment of the recording / reproducing apparatus of the present invention.

The recording / reproducing apparatus 50 of this embodiment is based on the principle of an atomic force microscope, and has the following points.
This is different from the recording / reproducing device 10 shown in FIG.

(1) As displacement detecting means for detecting a change in the surface shape of the recording medium 42 as displacement of the probe 51,
It includes a laser 70 for detecting the displacement of the probe 51 by detecting the displacement of the cantilever 52 in the illustrated Z-axis direction, a photodetector 71 and a position detection circuit 72.

(2) The cantilever beam 52 not only supports the probe 51 but also functions as a force-displacement converter. The probe force is generated by the spring force of the elastic cantilever beam 52. It has a structure that converts a force acting between the recording medium 51 and the recording medium 42 into a displacement. The cantilever 52
Can be formed by applying a silicon etching technique.
That is, by using the anisotropic etching of the known silicon crystal, it is possible to form the cantilever of S _i O ₂ of length 100 [mu] m, a width 20μm and a thickness of 1 [mu] m. Also, the S _i O ₂ surface, in order to impart conductivity, A
u film is deposited.

(3) The band-pass filter 65, the modulation circuit 66, the first and second tuning detection circuits 67 and 68, and the comparator 69 perform the tracking recorded on the recording medium 42 from the displacement detected by the displacement detecting means. Play the information,
It functions as tracking control information detecting means for detecting tracking control information necessary for tracking control of the probe 51 from the reproduced tracking information. Here, the output signal of the position detection circuit 72 is input to the bandpass filter 65.

(4) The high-pass filter 63 functions as recorded information reproducing means for reproducing recorded information recorded on the recording medium 42 from the displacement detected by the displacement detecting means. Here, the output signal of the position detection circuit 72 is input to the high-pass filter 63.

(5) Reproduction signal demodulation circuit 2 shown in FIG.
4, the low-pass filter 15 and the Z-direction control circuit 16 are not included.

Recording medium 4 used in recording / reproducing device 50
2 is a glass metal prepared using a well-known splat quenching method, specifically, Rh which is a kind of alloy glass.
-Zr is used. In addition, in order to secure sufficient flatness (0.1 nm rms or less), A
Physical etching such as r ⁺ ions is performed.

Next, the recording operation of the recording / reproducing apparatus 50 will be described.

As a first write condition, the probe 51
Between the recording medium 42 and the recording medium 42 via a bias circuit 60.
After applying a voltage of 0 V and setting the magnitude of a tunnel current flowing between the probe 51 and the recording medium 42 to 1 nA (a value normally passed when a sample is observed with a scanning tunneling microscope), the magnitude of the tunnel current is determined. Is changed to 200 nA and then returned to 1 nA, the surface of the glass metal is melted by Joule heat, and small recording bits are formed. At this time, the size of the recording bit is 20 nm in diameter and 5 nm in height.
Becomes

As a second writing condition, the magnitude of a tunnel current flowing between the probe 51 and the recording medium 42 by applying a voltage of 1.5 V by the bias circuit 60 between the probe 51 and the recording medium 42 To 1 nA,
After setting the tunnel current to 200 nA,
When the recording bit is formed in the same manner by returning to A, the size of the formed recording bit is 30 nm in diameter and 10 nm in height due to the difference in the applied energy.
Becomes

Therefore, a recording bit string in which tracking information is superimposed on recording information can be formed by utilizing the recording state under the first writing condition, the recording state under the second writing condition, and the non-recording state. The recording bit string formed at this time is the same as that shown in FIG.

Next, the reproducing operation of the recording / reproducing apparatus 50 will be described.

After moving the probe 51 to a desired recording bit string, the displacement of the cantilever 52 is detected while relatively scanning the probe 51 along the recording medium 42. In other words, the recording bit string displaces the cantilever 52 as unevenness information on the surface of the recording medium 42. The measurement of the position of the cantilever 52 in the illustrated Z-axis direction at this time is performed by detecting the laser beam emitted from the laser 70 and reflected by the cantilever 52 by the photodetector 71. An electric signal output from the photodetector 71 and indicating the position of the cantilever 52 in the illustrated Z-axis direction is input to a position detection circuit 72 and converted into an electric signal indicating the displacement of the cantilever 52. Here, the electrical signal indicative of the displacement of the cantilever beam 52, the reproduced signal S in addition to the long wavelength of the tracking signal T _P
Because it is also included, by inputting an electrical signal indicative of the displacement of the cantilever beam 52 to the high-pass filter 63, by removing the tracking signal T of long wavelength, taking out a reproduction signal S _P.

The electric signal indicating the amount of displacement of the cantilever 52 is also input to the band-pass filter 65, where the short-wavelength reproduced signal _SP is removed and only the tracking signal T is extracted. Here, the tracking signal T is the first signal described above.
By using a signal similar to the tracking signal T used in the recording / reproducing apparatus 10 of the embodiment, the modulation circuit 66, the first and second tuning detection circuits 67 and 68, and the comparator 69 convert the recording bit string of the probe 51 from the recording bit string. Direction and amount of shift can be detected. Therefore, also in the recording / reproducing apparatus 50 of the present embodiment, the XY scanning mechanism 57 is controlled by the XY scanning control circuit 58 in accordance with the detected deviation direction and deviation amount, so that the recording medium 42 can be processed for tracking. In addition, it is possible to read out recorded information while performing tracking control with high accuracy without performing control such as wobbling.

FIG. 5 is a block diagram showing a third embodiment of the recording / reproducing apparatus of the present invention.

The recording / reproducing apparatus 110 of this embodiment superimposes recording information and tracking information on a time division basis. That is, a synchronization signal is generated by a synchronization signal generation circuit 131, and two signals having phases different from the synchronization signal are generated using a first phase shifter 132 and a second phase shifter 133, respectively. And these two signals into a pulse generator 12
By inputting to 1, a pulse voltage is applied to the probe 111 by dividing one cycle of the synchronization signal into a time area for tracking information and a time area for recording information.
The modulation method used at this time is a pulse position modulation method. That is, information is transmitted based on the amount of deviation from the reference position.

[0062] reproduction operation of the recording and reproducing apparatus 110 receives the tunnel voltage V _t which is output from the current-voltage conversion circuit 114 to the sync pulse separator circuit 141, after separating the sync pulses from the tunnel voltage V _t, the record information And a time domain for tracking information in a third phase shifter 142.
And by the fourth phase shifter 144, the first demodulation pulse generation circuit 143 and the reproduction signal demodulation circuit 124 extract the recording information (reproduction signal S _R ), and
The tracking information is extracted by the demodulation pulse generation circuit 145 of FIG.

As the recording medium 102, a glass metal prepared by a known splat quenching method, specifically, Rh-Zr, which is a kind of alloy glass, is used. In addition, in order to ensure sufficient flatness (0.1 nm rms or less), the produced glass metal has been subjected to physical etching such as Ar ⁺ ions.

Next, the recording operation of the recording / reproducing apparatus 110 will be described.

As a writing condition, a voltage of 1.0 V is applied between the probe 111 and the recording medium 102 via the bias circuit 120 to set a tunnel current flowing between the probe 111 and the recording medium 102 at 1 nA. Thereafter, when the magnitude of the tunnel current is set to 200 nA and then returned to 1 nA, the surface of the glass metal is melted by Joule heat, and small recording bits are formed. At this time, the size of the recording bit is 20 nm in diameter and 5 nm in height. FIG. 6A shows an example of the recording bit string formed in this manner.
Shown in At this time, in order to distinguish it from other pulses,
The synchronization pulse was applied continuously.

Assuming that one cycle of the synchronization signal is T ₀ , FIG.
The portion indicated by T ₁ in (B) is a time domain for the tracking information, the portion indicated by T ₂ is a time domain for recording information. The recorded information is a reference pulse position (FIG. 6).
(B) is transmitted by the amount of deviation.

In the recording / reproducing apparatus 110 of this embodiment, the first information described above can be obtained by making the tracking information different between adjacent tracks on the recording medium 102.
Similarly to the recording / reproducing apparatus 10 of the embodiment and the recording / reproducing apparatus 50 of the second embodiment, the modulation circuit 126, the first tuning detection circuit 127, the second tuning detection circuit 128, and the comparator
With 129, the direction and amount of displacement of the probe 111 from the recording bit string can be detected. Therefore, in the recording / reproducing apparatus 110 of the present embodiment, the XY scanning control circuit 118 controls the XY scanning mechanism 117 in accordance with the detected shift direction and shift amount, so that the recording medium 102 can be processed for tracking. In addition, it is possible to read out recorded information while performing tracking control with high accuracy without performing control such as wobbling.

[0068]

Since the present invention is configured as described above, the following effects can be obtained.

The tracking information can be recorded on the recording medium together with the recording information. Further, only the tracking information is extracted from the signal in which the recording information read at the time of reproduction and the tracking information are superimposed, and the tracking control information (for example, probe information) is obtained. (A deviation direction and a deviation amount from the recording bit string of the recording medium), so that recording is performed while performing tracking control with high accuracy without performing processing for tracking on the recording medium and without performing control such as wobbling. Information can be read.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a diagram schematically showing a method of forming a recording bit string on the recording medium shown in FIG. 1 by superimposing tracking information together with recording information.

3A and 3B are diagrams for explaining a reproducing operation of the recording / reproducing apparatus shown in FIG. 1, wherein FIG. 3A shows a waveform of a tunnel voltage, FIG. 3B shows a waveform of a recording signal, and FIG. () Is a diagram showing a waveform of a tracking signal.

FIG. 4 is a block diagram showing a second embodiment of the recording / reproducing apparatus of the present invention.

FIG. 5 is a block diagram showing a third embodiment of the recording / reproducing apparatus of the present invention.

6 is a diagram schematically showing a recording bit string formed on a recording medium in the recording / reproducing apparatus shown in FIG. 5,
(A) is a diagram showing an example of a formed recording bit string,
(B) is a diagram showing a time area for tracking information and a time area for recording information.

[Explanation of symbols]

1, 41, 101 substrate 2, 42, 102 recording medium 10, 50, 110 recording / reproducing device 11, 51, 111 probe 12, 52, 112 cantilever 13, 53, 113 Z-direction scanning mechanism 14, 54, 114 current Voltage conversion circuit 15, 115 Low-pass filter 16, 116 Z-direction control circuit 17, 57, 117 XY scanning drive mechanism 18, 58, 118 XY scanning control circuit 19, 59, 119 Microcomputer 20, 60, 120 Bias circuit 21, 61 , 121 Pulse generation circuit 22, 62, 122 Reference signal generation circuit 23, 63 High-pass filter 24, 124 Reproduction signal demodulation circuit 25, 65 Band-pass filter 26, 66, 126 Modulation circuit 27, 67, 127 First tuning detection circuit 28, 68, 128 Second tuning detection circuit 29, 69, 129 Comparator 70 Laser 71 Photodetector 72 Position detection circuit 131 Synchronization signal Raw circuit 132 First phase shifter 133 Second phase shifter 141 Synchronous pulse separation circuit 142 Third phase shifter 143 First demodulation pulse generation circuit 144 Fourth phase shifter 145 Second demodulation pulse generation circuit J _t tunneling current V _t tunnel voltage B _I record information only recording bits and the recording bit B _iT recording information and tracking information is superimposed showing T tracking signal S _R recording signal S _P reproduced signal R reference signal X, Y, Z axis

Continuation of the front page (72) Inventor Haruki Kawata 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-4-350510 (JP, A) JP-A-4-212739 ( JP, A) JP-A-55-87349 (JP, A) JP-A-61-32273 (JP, A) JP-A-63-200372 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) G11B 9/14 G11B 21/10

Claims (4)

(57) [Claims] 1. A while relatively scanning the probe along the non-recording two or more types of state changes that can be formed recording medium other than the state, predetermined in the recording information at a predetermined position on said recording medium By applying a pulse voltage between the probe and the recording medium according to a digital signal on which period tracking information is superimposed, two types of states are recorded on the recording medium.
Forming an information bit of the state, and detecting a signal due to physical interaction between the probe and the recording medium while relatively scanning the probe along the recording medium on which the information bit is formed. Detecting the tracking information from the detected signal, and performing tracking in accordance with the tracking information , wherein the period of the tracking information is the information bit interval.
Longer than and adjacent to any track on the recording medium
A recording / reproducing method, wherein two adjacent tracks are different from each other . 2. The recording / reproducing method according to claim 1, wherein a signal due to the physical interaction is detected from a tunnel current flowing between the probe and the recording medium. 3. The recording / reproducing method according to claim 1, wherein a signal due to the physical interaction is detected from an atomic force acting between the probe and the recording medium. 4. A recording / reproducing apparatus for performing recording / reproducing using the recording / reproducing method according to claim 1, 2 or 3 .