JP3372841B2 - Tracking mechanism and tracking method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking mechanism and a tracking method in a recording / reproducing apparatus for recording / reproducing information on / from a medium by relatively scanning the medium with a probe. For example, a high density using the principle of STM. The present invention relates to a tracking mechanism and a tracking method in a large capacity memory device.

[0002]

2. Description of the Related Art In recent years, a scanning tunneling microscope (hereinafter abbreviated as STM) has been developed which enables direct observation of the electronic structure of a conductor [G. Binning et al. Phys.
Rev. Lett, 49, 57 (1982)], it has become possible to measure a real space image with high resolution regardless of whether it is a single crystal or a polycrystal. Since then, a scanning probe microscope (S
PM), and further research and development of fine processing technology applying SPM for the purpose of exerting an electrical, chemical or physical action on the substrate. Furthermore, such S
PM technology is also being applied to memory technology. For example,
JP-A-63-161552, JP-A-63-161
553 and the like use a thin film layer of a material having a memory effect on the switching characteristics of voltage and current as a recording layer, for example, a thin film layer of a π electron diameter organic compound or a chalcogen compound,
A method of performing recording / reproduction by STM is disclosed. By using this method and setting the recording bit size to 10 nm in diameter, an information processing apparatus having a recording density of 10 ¹² bits / cm ² can be realized.

Generally, when reading information recorded on a medium, it is necessary to relatively move an information reading probe along an information string on the medium. For that purpose, it is necessary to know the position of the information string by some method and move the probe to that position. First, as a method for detecting the position of an information string, a method is known in which a physical track is formed on a medium and a probe is placed along the track. Japanese Unexamined Patent Publication No. 1-107341 discloses a method of forming a V-shaped groove as a track on the surface of a recording medium and controlling the probe electrode so that it is always located at the center of this groove. Further, JP-A-1-133239 discloses a method in which a track is formed of a conductive band layer under a recording medium, a tracking signal is applied to the track, and feedback control is performed based on the tracking signal detected by a probe. Has been done. Further, as a method of tracking an information string without forming a special track on the medium, Japanese Patent Laid-Open No. 4-212737 discloses a method of recording a recording bit while vibrating a probe with a small amplitude in a direction perpendicular to the bit string. A tracking method is disclosed which detects a position and controls so as to eliminate the positional deviation.

On the other hand, a method has been proposed in which feedback control is not performed with respect to a positional deviation, but information is read by scanning the vicinity of an information string at a certain density to eliminate tracking control. ing. For example, in JP-A-2-050333, tracking is not performed, and during reproduction, the probe is scanned at a density higher than the recording density to read information, and the recorded information is reproduced using a pattern recognition technique. A method is disclosed. Further, Japanese Patent Laid-Open No. 4-364244 discloses a method of reproducing information by using a logical sum signal of a plurality of scanning information sequences as a reproduction signal without performing a process called pattern recognition. Furthermore, JP-A-4-35523
According to Japanese Patent Laid-Open No. 1-58, the preliminary scanning is performed twice before the recording / reproducing scanning, the tunnel currents obtained at that time are respectively integrated, and the operation output value is obtained to obtain the first preliminary scanning locus. On the other hand, a method is disclosed in which the actual center position of the signal train is detected from the operation output value of the second preliminary scanning locus and the third scan is performed near the center of the signal train to obtain a reproduction signal.

[0005]

However, in the method of creating a physical track on a medium as disclosed in JP-A-1-107341 and JP-A-1-133239, the step of providing the physical track is There is a problem in that the process of producing the recording medium becomes complicated and the processing precision of ultra-high precision is required, which is technically and costly. Further, in the method disclosed in Japanese Patent Application Laid-Open No. 4-212737, in order to perform scanning at high speed, the frequency of microvibration perpendicular to the direction of the information sequence must be set higher than that, so the scanning speed is microvibration. There was a problem that it was limited by the highest frequency. JP-A-2-
The method using pattern recognition disclosed in Japanese Patent No. 050333 also takes a long time for scanning in order to perform high-density reading, and also requires a complicated and time-consuming step of pattern recognition in post-processing. There was a point. JP-A-4-364244 and JP-A-4-35
The method disclosed in Japanese Patent No. 5231 also has a problem in that reading scanning takes time because scanning of three or more times is required to read one information row.

Therefore, in order to solve the above-mentioned problems, the present invention compares the reproduced signals of the tracking bits with each other to record / reproduce the data without adopting the problematic method as in the conventional one. It is an object of the present invention to provide a tracking mechanism and a tracking method capable of performing highly accurate, high-speed and stable tracking by the same method.

[0007]

In order to solve the above problems, the present invention is characterized in that a tracking mechanism and a tracking method are configured as follows. That is, the tracking mechanism of the present invention is a tracking mechanism in a recording / reproducing apparatus that relatively scans a medium with a probe to record / reproduce information on / from the medium, and the first and second tracking mechanisms have an interval different from a tracking bit string .
A pair of probes consisting of a pair of probes , and the first and second pro- cesses detected by the scanning by scanning the pair of probes.
Means for performing tracking control by comparing the outputs of the cables . The tracking mechanism
Are characterized by having a plurality of pairs of the above-mentioned probe.
It The tracking mechanism controls the tracking control.
Means for comparing the outputs of the multiple probe pairs
It is a means to perform tracking control by
There is. The means for controlling the tracking of the probe in the tracking mechanism of the present invention includes the first and second portions detected by scanning the tracking bit string .
Output of each probe or in the multiple probe pairs
Comparing the outputs , and outputting a signal having a sign and an absolute value according to the comparison result, an integrating means for integrating the history of the signal output from the comparing means and the past signal, and the integrating means. It is characterized by being constituted by an amplifying means for amplifying an output signal and outputting it as a control signal. Further, the tracking mechanism of the present invention is characterized in that the first and the first bits detected by scanning the tracking bit string are detected.
And the output of the second probe or the plurality of pairs of probes
It is characterized in that it has a binarizing means for binarizing the output at. Further, the tracking mechanism of the present invention is provided with the output of the first and second probes or the output of the composite probe.
Peak hold means for holding the maximum value of the outputs from the outputs of several pairs of probes, and threshold detection means for outputting a reset signal to the peak hold means when the output exceeds a certain threshold value. It is characterized by having and. Further, the tracking mechanism of the present invention is characterized in that the tracking bit string also serves as a data bit string. In addition, the recording of the present invention
The raw device has the tracking mechanism described above.
I am trying. The tracking method of the present invention, the
Comprises a probe pair consisting of first and second probe by the probe pair to form a tracking bit string of different intervals between the probe interval, and track scanning the probe pair during the recording and reproducing, is detected by the scanning of the tracking bit string Tracking control is performed by comparing the outputs of the first and second probes . Further, the tracking method of the present invention
Are characterized by having a plurality of pairs of the above-mentioned probe.
It In addition, the tracking method of the present invention,
Means for controlling the output of the plurality of pairs of probes.
Compared with tracking control,
is doing. Further, the tracking method of the present invention is such that the first and second detections made by scanning the tracking bit string are performed.
And the output of the second probe or the plurality of sets of probes
The outputs of the pair are compared by a comparison means, output as a signal having a sign and an absolute value according to the comparison result, added with the history of past signals, and then amplified to be a control signal. I am trying. Further, the tracking method of the present invention is the output of the first and second probes detected by scanning the tracking bit string or the output of the first probe or the second probe.
The output of the plurality of pairs of probes is binarized by the binarizing means. Further, the tracking method of the present invention is the output of the first and second probes detected by scanning the tracking bit string or
When the maximum value of the output of the plurality of pairs of probes is held by the peak hold means and the output exceeds a certain threshold value, a reset signal is sent from the threshold value detection means to the peak hold means. Is output. The tracking method of the present invention is characterized in that the tracking bit string also serves as a data bit string. Further, the truckin of the present invention
The scanning mechanism relatively scans the medium with the probe and
Tracking in a recording / reproducing apparatus for recording / reproducing information
Mechanism, which has an interval different from the tracking bit string
And the probes are arrayed from 1st to Nth
Probe group having a plurality of probes, and the probe group
And even numbered probes detected by the scan
Of the signals from the even-numbered probes and
Means for comparing the totals and performing tracking control,
It is characterized by that.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, with the above-described structure, a tracking bit sequence is generated by shifting a probe interval and a tracking bit interval, and a reproduction signal of the tracking bit is compared to perform the same method as data recording / reproduction. This enables high-precision, high-speed and stable tracking. Further, by using a plurality of sets of probes for tracking, a more stable system can be realized, it becomes possible to cope with probe loss and to share a tracking bit string and a data bit string. In addition, the tracking bit string and the data bit string can be shared by using the mechanism for holding the output of the immediately preceding bit in the bit-free section.

An outline of a recording / reproducing apparatus to which the present invention is applied will be described with reference to FIG. A plurality of probes 605 are arranged so that a probe 604 provided at the tip contacts a recording medium 603 composed of a recording layer 602 on a conductive substrate 601. In each probe 605, the probe 604 is supported by an elastic body 606 that elastically deforms so as to bend. If the elastic constant of elastic deformation of the elastic body 606 is about 0.1 [N / m] and the elastic deformation amount is about 1 [μm], the contact force of the probe with respect to the recording medium is about 10 ^−7. It becomes about [N]. Upon receiving the position control signal from the position control circuit 613 controlled by the control computer 614, the xyz drive mechanism 607 drives the xyz stage 608 attached to the recording medium 603, and the probe 605 and the recording medium 603 are relatively moved. Move in three dimensions. The position of the probe 604 in the xy direction and the z direction is adjusted with respect to the recording medium 603, and the probe 6
The probe 605 is aligned so that the tip 04 of the recording medium 603 is brought into contact with the recording medium 603 at a desired position and with a desired contact force. When scanning the recording medium 603 with the probe 605 in the recording / reproducing apparatus, the probe 6
The tip of the probe 604 on 05 always keeps contact with the recording medium 603.

According to such a contact scanning method, when scanning is performed with the tip of the probe 604 in contact with the recording medium 603, even if the surface of the recording medium 603 has irregularities, the elastic body 6
Since this is absorbed by the elastic deformation of 06, the probe 604
The contact force between the tip and the surface of the recording medium 603 is kept substantially constant, and the tip of the probe 604 and the surface of the recording medium 603 can be prevented from being destroyed. Since this method does not require means such as a piezo element for aligning individual probes in the z direction,
The structure is not complicated, and it is particularly suitable for an apparatus having a plurality of probes. Further, since the feedback control of the z-direction position of each probe 605 with respect to the recording medium 603 is unnecessary, the probe 605 with respect to the recording medium 603 is not necessary.
It becomes possible to perform high speed scanning. The recording signal generated from the recording control circuit 611 controlled by the control computer 614 is changed to a recording system by a changeover switch 609.
And applied to the recording medium 603 from each probe 604. In this way, recording is locally performed on the portion of the recording layer 602 where the tip of the probe 604 contacts.

The recording layer 602 in the above-described device is made of a material whose current value flowing by voltage application changes. As a specific example, firstly, Japanese Patent Laid-Open No. 63-16
1552 and Japanese Patent Application Laid-Open No. 63-161553, such as polyimide and SOAZ (bis-n-).
LB film (= Langmuir-Blodget) having an electric memory effect such as octyl squarylium azulene
A cumulative film of organic monomolecular films prepared by the te method). This material changes the conductivity of the LB film (OFF state → ON state) when a voltage (about 5 to 10 [V]) higher than the threshold value is applied between the probe, the LB film, and the substrate. The current flowing when the bias voltage (about 0.01 to 2 [V]) is applied increases.

As a second specific example, GeTe, GaS
Examples of the amorphous thin film material include b and SnTe. This material applies a voltage between the probe-amorphous thin film material-substrate,
The heat generated by the flowing current causes a phase transition from amorphous to crystalline. This changes the conductivity of the material and increases the current that flows when a reproducing bias voltage is applied. A third specific example is an oxidizing metal / semiconductor material such as Zn, W, Si, or GaAs. When a voltage is applied between the probe and the oxidizable metal / semiconductor material, this material reacts with water adsorbed on the material surface or oxygen in the atmosphere due to the flowing current, and an oxide film is formed on the surface. Therefore, the contact resistance of the material surface changes, and the current that flows when a bias voltage is applied decreases. Now, reproduction of the bits recorded as described above is performed as follows. After switching the signal wiring from each probe 605 to the reproduction system by the switch 609, a bias voltage is applied between the probe 604 and the substrate 601 by the bias voltage applying means 610, and the current flowing therethrough is reproduced in the reproduction control circuit. Detection at 612. The recorded bit portion on the recording medium 603 has a larger current (or less current) than a portion not recorded, so that the reproduction control circuit 612 detects this difference in current and outputs it as a reproduction signal. Output to.

The structure and operation of the present invention will be described below with reference to the drawings. In FIG. 1, d indicates the distance between the two probes 101 and 102. On the other hand, the tracking bit string 103 is formed at an interval deviated from the probe interval d by Δd. FIG. 1 shows an example in which the bit string interval is widened by d + Δd, that is, Δd. Of course, the bit string interval may be narrowed by d-Δd, that is, Δd. Here, when the two probes arranged in parallel scan the recording medium on which the bits are written with the bias voltage applied in the direction parallel to the bit string (the direction of the arrow), the probes scan the bit 103. The current between the probe and the recording medium increases (or decreases) as it passes through. Here, the outputs of the two probes are input to the comparison circuit 204 to compare the current values.
As shown in FIG. 3, when the probe is at the target position, no error signal is output from the comparator. However, when an error occurs in the vertical direction with respect to the bit string as shown in FIGS. 4 and 5, an error signal having a polarity according to the direction of the error and an absolute value according to the error amount is output from the comparator. Tracking control is performed using this. Although the case where the number of probes is two has been described above, a plurality of sets of probes may be used for tracking. In this case, the error output is obtained as the sum of the signals from all the probes used for tracking, so that averaging is achieved, and a more robust system is realized. For this reason, when the number of probes is sufficiently large, it is possible to use the tracking bit string as a data bit string or to make the number of probes used for tracking an odd number due to manufacturing reasons, failures, and the like. Also, until the next bit appears,
It is also possible to use the tracking bit string as a data bit string by using a mechanism that holds the value of the previous bit. Depending on the recorded data, there may be a situation where a bitless section continues, but this mechanism can deal with it. The recording / reproducing apparatus to which the present invention is applied is not limited to the recording / reproducing apparatus. It is also applicable to other recording / reproducing devices such as a magnetic recording / reproducing device and a magneto-optical recording / reproducing device.

[0014]

EXAMPLES Examples of the present invention will be described below. [Embodiment 1] Embodiment 1 in which the tracking mechanism of the present invention is applied to the recording / reproducing apparatus having the above-described configuration will be described in detail below with reference to FIGS. First, two probes 101 and 102 integrally formed at 200 μm intervals were attached to the above device. As the recording layer 602, an LB film composed of 6 layers of polyimide monomolecular films was used. Then 2
The book probe was used for a linear velocity of 0.
A linear scan was performed at 1 mm / s. The voltage pulse was applied 2048 times using the first probe 101 during the scanning. The voltage is 5.5 V and the application time is 0.3 μsec. The diameter of the generated tracking bit is about 10n
m and the bit interval was about 50 nm.

Next, the two probes are returned to their original positions, and the two probes are moved to the side of the second probe by 4 nm when viewed from the first probe 101, and then the linear velocity is 0.1 mm over a length of 100 μm. Scanning was performed linearly at / s. During the scan, the second probe 102 was used to apply 2048 voltage pulses. Voltage is 5.5V, application time is 0.3
μsec. Generated tracking bit 103
Had a diameter of about 10 nm and a bit interval of about 50 nm.

Next, the reproduction operation of the bit string was performed while performing the tracking. Here, the tracking mechanism used in this embodiment will be described with reference to FIG. The current signal of the recording bit output from the two probes is converted into a voltage signal by the I / V conversion circuit 201, and the amplification circuit 20
After being respectively amplified by 2, the low-pass filter 2
It is input to the comparison circuit 204 through 03. The comparison circuit 204 compares the input signals and outputs a voltage signal having a polarity and an absolute value according to the difference. This voltage signal passes through the PID filter 205, is added to the past history by the integrating circuit 206, and is amplified by the amplifying circuit 207.
The position control signal is added to control the xyz drive mechanism 607 in FIG. After returning the two probes to their original positions, a bias voltage of 1.5 V was applied to the two probes, and scanning was performed at a linear velocity of 2 mm / s while performing tracking using the tracking mechanism. No replay error was found as a result of reciprocating replay operation and monitoring the replay signal.

[Embodiment 2] With reference to FIGS. 7 and 8, a second embodiment in which the tracking mechanism of the present invention is applied to the recording / reproducing apparatus having the above-described structure will be described in detail below. First, 128 probes integrally formed at intervals of 50 μm were attached to the above device. As the recording layer 602, an LB film composed of 6 layers of polyimide monomolecular films was used. The entire probe is then subjected to a linear velocity of 0.
A linear scan was performed at 1 mm / s. The voltage pulse was applied 2048 times using the first probe 101 during the scanning. The voltage is 5.5 V and the application time is 0.3 μsec. The diameter of the generated tracking bit 103 is about 1
The bit spacing was 0 nm and the bit interval was about 50 nm.

Next, the entire probe is returned to the original position, and the 128th probe 708 is seen from the first probe 101.
After moving the entire probe 4 nm to the side, the length is 100μ
The scanning was performed linearly at a linear velocity of 0.1 mm / s over m. During the scanning, the 128th probe 701 is used to
The voltage pulse was applied 048 times. The voltage is 5.5 V and the application time is 0.3 μsec. The diameter of the generated tracking bit was about 10 nm, and the bit interval was about 50 nm. Next, using the first and the 128th probes, a total of 12 from the second to the 127 while tracking is performed.
The recording operation of the bit string was performed using the six probes 102. Here, the tracking mechanism used in this embodiment will be described with reference to FIG. The recorded bit current signals output from the first and 128th probes are I / V.
After being converted into a voltage signal by the conversion circuit 201 and amplified by the amplification circuit 202, the signal is passed through the low-pass filter 203, binarized by the binarization circuit 801, and then input to the comparison circuit 204. The comparison circuit 204 compares the input signals and outputs a constant voltage signal having a polarity according to the difference. This voltage signal is the PID filter 2
After passing through 05, the integration circuit 206 adds the past history, the amplification circuit 207 amplifies the history, and the position control signal to control the xyz drive mechanism 607 in FIG.

After returning the entire probe to its original position, a bias voltage of 1.5 V is applied to the first and 128th probes and scanning is performed at a linear velocity of 2 mm / s while performing tracking using the above tracking mechanism. I went. During the scan
A total of 126 probes 102 from the second to 127th were used, and a voltage pulse of 2048 at maximum was applied to each probe according to a data string prepared in advance. The voltage is 5.
5V, application time is 0.3 μsec. The generated data bits 702 had a diameter of about 10 nm and a bit interval of about 50 nm. As a result of monitoring the reproduction signals of the first and 128th probes, no reproduction error was recognized. Next, the reproduction operation of the data bit string was performed while performing the tracking. After returning the entire probe to its original position, a bias voltage of 1.5 V is applied to all the probes from the first to the 128th, and the linear velocity of 2 mm / s is applied to the first and the 128th probes.
The probe was used for scanning while performing tracking using the above tracking mechanism. Second to twelfth during scanning
The reproduction signals of 126 probes 102 in total up to 7 were monitored. As a result of performing a reciprocating operation of 50 round trips, no reproducing error was recognized.

[Third Embodiment] A third embodiment in which the tracking mechanism of the present invention is applied to the recording / reproducing apparatus having the above structure will be described in detail below with reference to FIGS. First, 128 probes integrally formed at intervals of 50 μm were attached to the above device. As the recording layer 602, an LB film composed of 6 layers of polyimide monomolecular films was used. The entire probe is then subjected to a linear velocity of 0.
A linear scan was performed at 1 mm / s. During scanning, a total of 64 odd-numbered probes were used to apply a voltage pulse up to 2048 times for each probe in accordance with the data prepared in advance. Voltage is 5.5 V, application time is 0.3 μse
c. The diameter of the generated data bit is about 10n
m and the bit interval was about 50 nm. Next, the entire probe is returned to the original position, and the entire probe is moved 4 nm toward the 128th probe 701 side as viewed from the first probe 101, and then the linear velocity is 0.1 m over a length of 100 μm.
Scanning was performed linearly at m / s. During scanning, a total of 64 even-numbered probes were used, and each probe was applied with a voltage pulse at a maximum of 2048 times in accordance with a data string prepared in advance. Voltage is 5.5 V, application time is 0.3 μsec
Is. The diameter of the generated data bit is about 10 nm,
The bit spacing was about 50 nm.

Next, the reproduction operation of the data bit string was performed while tracking was performed using all the probes. Here, the tracking mechanism used in this embodiment will be described with reference to FIG. The current signals of the recording bits output from all the probes are converted into voltage signals by the I / V conversion circuit 201, amplified by the amplification circuit 202, passed through the low-pass filter 203, and then compared by the comparison circuit 20.
4 is input. The comparison circuit 204 compares the sum of the signals from the odd-numbered probes and the sum of the signals from the even-numbered probes, and outputs a voltage signal having a polarity and an absolute value according to the difference. This voltage signal is sent to the PID filter 205.
, And the past history is added by the integration circuit 206,
After being amplified by the amplifier circuit 207, it is added to the position control signal to control the xyz drive mechanism 607 in FIG. After returning the entire probe to its original position, apply a bias voltage of 1.5 V to all the probes to obtain a linear velocity of 2 mm / s.
Then, scanning was performed while performing tracking using the above tracking mechanism. The reproduced signals of all probes were monitored during scanning. As a result of performing a reciprocating operation of 50 round trips, no reproducing error was recognized. Next, the output from the first probe to the tracking mechanism was cut off, and the reproducing operation of the data bit string was performed in the same manner, but there was no problem in the tracking operation.

[Embodiment 4] With reference to FIGS. 11 and 12, Embodiment 4 in which the tracking mechanism of the present invention is applied to the recording / reproducing apparatus having the above-mentioned structure will be described in detail below.
First, two probes integrally formed at 200 μm intervals were attached to the above device. As the recording layer 602, an LB film composed of 6 layers of polyimide monomolecular films was used. Next, the two probes were linearly scanned at a linear velocity of 0.1 mm / s over a length of 100 μm. First during scanning
Using the probe 101 of No. 2, the voltage pulse was applied up to 2048 times in accordance with the data prepared in advance. The voltage is 5.5 V and the application time is 0.3 μsec. The diameter of the generated data bit was about 10 nm, and the bit interval was about 50 nm. Next, the two probes are returned to their original positions, and the two probes are moved to the second probe 102 side by 4 nm as viewed from the first probe 101, and then the linear velocity is 0.1 mm / A linear scan was performed at s. During scanning, the second probe 102 is used to adjust the data sequence prepared in advance to a maximum of 20.
The voltage pulse was applied 48 times. The voltage is 5.5 V and the application time is 0.3 μsec. The diameter of the generated data bit was about 10 nm, and the bit interval was about 50 nm.

Next, the reproduction operation of the data bit string was performed while tracking was performed using the two probes. Here, the tracking mechanism used in this embodiment will be described with reference to FIG. The current signal of the recording bit output from all the probes is converted into a voltage signal by the I / V conversion circuit 201, amplified by the amplification circuit 202, passed through the low-pass filter 203, and then passed through the threshold circuit 1201 and the peak hold circuit. It is input to 1202. The threshold circuit 1201 uses the peak hold circuit 1 when the signal voltage exceeds a predetermined voltage value.
A reset signal is output to 202. The peak hold circuit 1202 compares the held peak voltage with the comparison circuit 2
Continue to output to 04. The comparison circuit 204 compares the signal from the first probe 101 with the signal from the second probe 102, and outputs a voltage signal having a polarity and an absolute value according to the difference. This voltage signal passes through the PID filter 205, is added to the past history by the integration circuit 206, is amplified by the amplification circuit 207, and is added to the position control signal to control the xyz drive mechanism 607 in FIG. After returning the entire probe to its original position, apply a bias voltage of 1.5 V to the two probes and apply a linear velocity of 2 mm.
The scanning was performed while tracking was performed using the above tracking mechanism at / s. During scanning, the reproduction signals of two probes were monitored. As a result of performing a reciprocating operation of 50 round trips, no reproducing error was recognized.

[0024]

As described above, according to the present invention, data recording / recording is performed by comparing the probe signal and the reproduction signal of the tracking bit string generated by shifting the interval.
High-precision, high-speed and stable tracking became possible by the same method as playback. Further, according to the present invention, it is possible to use a tracking bit string and a data bit string together by increasing the number of bit strings used for tracking or by using a mechanism for holding the output of the immediately previous bit in a portion where there is no bit. .

[Brief description of drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a tracking mechanism according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating the principle of the tracking mechanism of the present invention.

FIG. 4 is a diagram illustrating the principle of the tracking mechanism of the present invention.

FIG. 5 is a diagram illustrating the principle of the tracking mechanism of the present invention.

FIG. 6 is a diagram illustrating an overall configuration of a recording / reproducing apparatus to which the present invention is applied.

FIG. 7 is a diagram illustrating a second embodiment of the present invention.

FIG. 8 is a diagram illustrating a tracking mechanism according to a second embodiment of the present invention.

FIG. 9 is a diagram illustrating a third embodiment of the present invention.

FIG. 10 is a diagram illustrating a tracking mechanism according to a third embodiment of the present invention.

FIG. 11 is a diagram illustrating a fourth embodiment of the present invention.

FIG. 12 is a diagram illustrating a tracking mechanism according to a fourth embodiment of the present invention.

[Explanation of symbols]

101: probe 1 102: probe 2 103: Tracking bit 201: I / V conversion circuit 202: Amplifier circuit 203: Low-pass filter 204: Comparison circuit 205: PID filter 206: Integration circuit 207: Amplifier circuit 601: substrate 602: recording layer 603: recording medium 604: probe 605: probe 606: elastic body 607: xyz drive mechanism 608: xyz drive stage 609: Changeover switch 610: Bias applying means 611: recording control circuit 612: Regeneration control circuit 613: Position control circuit 614: Control computer 701: probe 128 702: Data bit 801: Binarization circuit 1201: Threshold circuit 1202: peak hold circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-321084 (JP, A) JP-A-8-287531 (JP, A) JP-A-5-109130 (JP, A) JP-A-2- 166626 (JP, A) JP-A-1-138624 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 21/10 G11B 9/00-9/14 G11B ^7/ 09- 7/10

Claims (16)

(57) [Claims] 1. A tracking mechanism in a recording / reproducing apparatus for recording / reproducing information on / from a medium by relatively scanning the medium with a probe, wherein the first and the second mechanisms have an interval different from a tracking bit string.
A probe pair consisting of a second probe , the probe pair is scanned, and the first pair detected by the scanning is detected .
Means for controlling tracking by comparing outputs of the first and second probes , and a tracking mechanism. 2. The method according to claim 1, wherein a plurality of pairs of the probe are provided.
The described tracking mechanism. 3. The tracking control means comprises
Track outputs by comparing the outputs of several probe pairs
The tracking machine according to claim 2, which is a means for controlling.
Structure. 4. The means for controlling the tracking of the probe is detected by scanning the tracking bit string.
Outputs of the first and second probes or the plurality of sets
Comparing means for comparing the outputs of the probe pairs, and outputting a signal having a sign and an absolute value according to the comparison result; an integrating means for integrating the history of the signal output from the comparing means and the past signal; The tracking mechanism according to any one of claims 1 to 3, wherein the tracking mechanism is configured by amplifying means for amplifying a signal output from the integrating means and outputting the amplified signal as a control signal. 5. The first and second tracking mechanisms are detected by scanning the tracking bit string .
Output of each probe or in the multiple probe pairs
The tracking mechanism according to claim 1, further comprising a binarizing unit that binarizes the output . Wherein said tracking mechanism, wherein the first and
The output of the second probe or the plurality of pairs of probes
Peak hold means for holding the maximum value of the output from the output, and when the output exceeds a certain threshold,
The tracking mechanism according to any one of claims 1 to 5, further comprising: a threshold detection unit that outputs a reset signal to the peak hold unit. 7. The tracking mechanism according to claim 6, wherein the tracking bit string also serves as a data bit string. 8. The tiger according to any one of claims 1 to 7.
Recording / reproducing apparatus having a locking mechanism. 9. A tracking method in recording / reproducing means for recording / reproducing information on / from a medium by relatively scanning the medium with a probe, comprising a probe pair consisting of a first probe and a second probe.
By the pair of probes to form a tracking bit string of different intervals between the probe interval, the probe pairs to track scanned during recording and reproduction, the tracking bit sequence the first and second probes is detected by scanning the <br/> A tracking method characterized by performing tracking control by comparing the outputs of the. 10. A plurality of pairs of the probe are provided.
Tracking method described in. 11. The tracking control means is the
Tracking control by comparing the output of multiple probe pairs
The tracking method according to claim 10, which is a means for performing. 12. Outputs of the first and second probes detected by scanning the tracking bit string, or
The outputs of the plurality of pairs of probes are compared by the comparison means, output as a signal having a sign and an absolute value according to the comparison result, and after being added to the history of past signals,
10. The control signal is amplified and used as a control signal.
11. The tracking method according to any one of 11 above. 13. Outputs of the first and second probes detected by scanning the tracking bit string, or
13. The tracking method according to claim 9, wherein the outputs of the plurality of pairs of probes are binarized by binarizing means. 14. Outputs of the first and second probes detected by scanning the tracking bit string, or
When the maximum value of the output is held by the peak hold means and the output exceeds a certain threshold value, a reset signal is output from the threshold value detection means to the peak hold means. The tracking method according to any one of claims 9 to 13, wherein 15. The tracking method according to claim 9, wherein the tracking bit string also serves as a data bit string. 16. A medium which is relatively scanned with a probe on the medium.
Track in a recording / reproducing apparatus for recording / reproducing information on / from
The mechanism of Has a different spacing from the tracking bit string and
Probes arranged from the 1st to the Nth probe
A probe group having a probe, The probe group is scanned, and an even number detected by the scanning
The sum of the signals from the eye probes and the even numbered probes
Tracking control by comparing the sum of signals from
When, A tracking mechanism comprising: