JP2000113532A - Information reproducing device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a multi-probe head to be exchanged by constituting the scanning area of a scanning means such that it scans in the area wider than the one with data recorded on a recording medium, namely, wider by the positional deviation of the probe. SOLUTION: dx0-3 and dy0-3 indicate deviation of a probe 0-3 from the reference position of each data block. Reproduction procedure in the case where the probe is exchanged is carried out by measuring the positional deviation of each probe and reproducing information based on it. The probe unit is positioned in the Y direction so that all probes are in the range in the Y direction of the data block. Then, the probe unit is positioned in the X direction, at the position where all probes are supposed to come to the left of the leading position of the data track. After that, the probe unit is scanned in the X direction, to the position where all probes are supposed to come to the right of the data track. If a reproducing signal is detected larger than a prescribed threshold value by each probe, it is demodulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information reproducing apparatus and an information reproducing method, and more particularly to a technical field of an information reproducing apparatus and an information reproducing method to which the principle of a scanning probe microscope having a plurality of probes is applied. is there.

[0002]

2. Description of the Related Art In recent years, a scanning tunneling microscope (hereinafter referred to as S) capable of observing the surface of a conductive material with a resolution of less than nanometers.
TM) (US Pat. No. 4,343,99).
No. 3), observations of the atomic arrangement of metal / semiconductor surfaces, orientation of organic molecules, etc. have been made on an atomic / molecular scale.
Also, by developing STM technology, the surface of insulating materials etc.
Atomic force microscope (hereinafter A)
FM) (US Patent No. 4,724,3).
No. 18). As a further development, a scanning near-field light microscope (hereinafter abbreviated as SNOM) for examining the surface state of a sample using evanescent light seeping out of a minute opening at the tip of a sharp probe [Durig et al. Appl. P
hys. 59, 3318 (1986)].
At present, these microscopes, which can measure various physical quantities of a sample surface such as tunnel current, electronic density of states, atomic force, intermolecular force, friction force, elasticity, evanescent light, magnetic force, etc. with high resolution, are known as scanning probe microscopes (hereinafter referred to as SPM). Abbreviated).

[0003] Such SPM technology is also being applied to memory technology. For example, JP-A-63-1615
No. 52, JP-A-63-161553 and the like,
A method is disclosed in which recording / reproducing is performed by STM using a thin film layer of a material having a memory effect on switching characteristics of voltage and current as a recording layer, for example, a thin film layer of a π-electron organic compound or a chalcogen compound as a recording medium. According to this method, by applying a voltage equal to or higher than a certain threshold value to the STM probe, recording is performed by causing a change in characteristics in a very small area on the recording medium immediately below the probe. Reproduction can be performed using the fact that the tunnel current flowing between the recording portion and the non-recording portion changes. Using this method,
If the recording bit size is 10 nm in diameter, an information processing device having a recording density of 10 ¹² bits / cm ² can be realized. In addition, when a voltage higher than a certain threshold value is applied as a recording medium, a material whose surface locally melts or evaporates to change its surface shape into a concave or convex shape, for example, by using a metal thin film such as Au or Pt, is used. Can be recorded and reproduced. Furthermore, in these SPM applied memory devices, it has been proposed that the recording / reproducing speed be significantly increased by performing recording / reproducing in parallel with a plurality of probe groups (multi-probe heads) created by micromachining technology. I have.

[0004]

However, conventionally, an SP having a multi-probe head as described above has been proposed.
In the M application memory, there is a problem that the multi-probe head cannot be easily replaced. This is because the interval between tracks on which information is recorded on a recording medium is about 10 to 20 nm. On the other hand, when a multi-probe head is formed by the existing micromachining technology, the distance between the tracks at the tip of the probe is about 100 to 200 nm. This is because an error occurs. Therefore, when trying to use different multi-probe heads during recording and playback, the probe cannot be positioned on the same track,
Information could not be reproduced using a multi-probe head different from that used for recording.

[0005] Therefore, when the probe of the probe is damaged, information cannot be read out. Therefore, it is necessary to increase the redundancy at the time of recording in order to improve the reliability, and the recording capacity is reduced. Further, when used as a removable medium, it is necessary to package the medium and the probe as a set, so that the cost of the recording medium is increased. Further, since the same probe must be used for recording and reproduction, the medium cannot be duplicated by a method such as stamping, and thus there is a problem that it is not suitable for a recording medium for mass distribution.

Therefore, the present invention solves the above-mentioned problems in the conventional art, and in an information recording / reproducing apparatus using a multi-probe head, it is possible to replace the multi-probe head to obtain a highly reliable and removable medium. It is an object of the present invention to provide an information reproducing apparatus and an information reproducing method which are inexpensive and can use a mass copying technique such as stamping.

[0007]

According to the present invention, in order to achieve the above object, an information reproducing apparatus and an information reproducing method are configured as follows. That is, the information reproducing apparatus of the present invention includes a probe unit having a plurality of probes, a scanning unit that relatively scans the probe unit with respect to a recording medium, and a plurality of the probe units in the probe unit that are generated due to a probe creation error. Measuring means for measuring the amount of displacement due to variation in the probe, the scanning range of the scanning means in a range wider than the range of data recorded on the recording medium by the amount of displacement of the probe. It is characterized by being configured to scan. Further, in the information reproducing apparatus of the present invention, the scanning unit scans the probe unit relative to the recording medium in a direction parallel to a data track, and the scanning unit scans the probe unit with respect to the recording medium. Means for moving between data tracks in a direction perpendicular to the data tracks in a moving step smaller than the interval between the data tracks. In the information reproducing apparatus of the present invention, when the scanning unit scans the probe unit relatively to the recording medium, the information is reproduced only when a reproduction signal from the probe is equal to or more than a predetermined threshold value. It is characterized by having demodulation means for demodulating a signal. Further, the information reproducing apparatus of the present invention is characterized by having buffering means for temporarily storing information demodulated by the demodulating means and transferring the information to the outside in a required order.
Further, the information reproducing apparatus of the present invention has a probe unit having a plurality of probes, a scanning unit for relatively scanning the probe unit with respect to a recording medium capable of erasing and re-recording, and a probe generation error. Measuring means for measuring a displacement amount due to variation of a plurality of probes in the probe unit, and data position reconstructing means for reconstructing the position of information recorded on the recording medium, the probe unit or When exchanging the recording medium, the data position reconstructing means removes the variation in the position of the data viewed from the probe based on the displacement amount of the probe measured by the measuring means. Is characterized by reconstructing the position of the information recorded in the. Further, in the information reproducing apparatus of the present invention, the scanning unit scans the probe unit relative to the recording medium in a direction parallel to a data track, and the scanning unit scans the probe unit with respect to the recording medium. Means for moving between data tracks in a direction perpendicular to the data tracks in a moving step smaller than the interval between the data tracks. In the information reproducing apparatus of the present invention, when the scanning unit scans the probe unit relatively to the recording medium, the information is reproduced only when a reproduction signal from the probe is equal to or more than a predetermined threshold value. It is characterized by having demodulation means for demodulating a signal.
Further, the information reproducing apparatus of the present invention is characterized by having buffering means for temporarily storing information demodulated by the demodulating means and transferring the information to the outside in a required order.

According to the information reproducing method of the present invention, in the information reproducing method of relatively scanning a probe unit having a plurality of probes with respect to a recording medium to reproduce recorded information, the probe unit generated by an error in producing a probe is used. Measuring means for measuring an amount of positional deviation due to variation of a plurality of probes in the probe unit, and when exchanging the probe unit or the recording medium, the positional deviation of the probe from the recorded range of data on the recording medium. It is characterized in that the scanning means can be scanned in a wide range by the amount. Further, in the information reproducing method of the present invention, when the probe unit is relatively scanned with respect to the recording medium, the reproduction signal is demodulated only when the reproduction signal from the probe is equal to or more than a predetermined threshold value. It is characterized by: Further, the information reproducing method according to the present invention is characterized in that information demodulated by demodulation of the reproduced signal is temporarily stored and transferred to the outside in a required order. Further, the information reproducing method of the present invention is an information reproducing method of reproducing a record information by relatively scanning a probe unit having a plurality of probes with respect to a recording medium,
A recording medium capable of erasing and re-recording, and a measuring unit for measuring a displacement amount due to a variation in a plurality of probes among the probe units caused by an error in creating a probe, and exchanging the probe unit or the recording medium. At this time, based on the amount of displacement of the probe measured by the measuring means, the data position reconstructing means eliminates the variation in the position of the data viewed from the probe, so that the information recorded on the recording medium is It is characterized in that the position is reconstructed. Further, in the information reproducing method of the present invention, when the probe unit is relatively scanned with respect to the recording medium, the reproduction signal is demodulated only when the reproduction signal from the probe is equal to or more than a predetermined threshold value. It is characterized by: Further, the information reproducing method according to the present invention is characterized in that information demodulated by demodulation of the reproduced signal is temporarily stored and transferred to the outside in a required order.

[0009]

According to the present invention, the scanning range of the scanning means can be made wider than the range in which the data is recorded on the recording medium by an amount corresponding to the variation in the probe. Can be used to replace the multi-probe head. Further, according to the present invention, when replacing the probe unit or the recording medium, the position of the data viewed from the probe by the data position reconstructing means based on the displacement amount of the probe measured by the measuring means. By reconstructing the position of the information recorded on the recording medium so as to eliminate the variation of the information, information that can be reproduced at the same speed as when using the same probe unit at the time of recording and at the time of reproduction A playback device can be realized. According to the present invention, by using the inter-data-track moving means to move the probe in a moving step smaller than the interval between the data tracks, all the probes can scan the data track. According to the present invention, when the scanning unit scans the probe unit relative to the recording medium, demodulation of the reproduction signal is performed only when the reproduction signal from the probe is equal to or greater than a predetermined threshold. By doing so, it is possible to demodulate the reproduction signal of only the probe scanning the data track. Also,
According to the present invention, buffering means for temporarily storing the demodulated information from the information demodulating means and transferring the demodulated information to the outside in the required order makes it possible for the order in which data is reproduced to vary among the probes. Is prevented from changing, and data can be output in a required order. According to the present invention, the displacement of the probe is measured at the time of replacement of the probe unit or the recording medium by using the probe displacement measurement means, thereby minimizing the driving range of the driving means and achieving high-speed operation. Thus, an information reproducing apparatus capable of reproducing information quickly can be realized.

[0010]

Embodiments of the present invention will be described below. [Embodiment 1] 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 205 are arranged such that a probe 204 provided at the tip comes into contact with a recording medium 203 composed of a recording layer 202 on a substrate 201 having conductivity. In each probe 205, the probe 204 is supported by an elastic body 206 that elastically deforms to bend. Multiple probes 205
Are integrally formed by a micro-machining technique to constitute the multi-probe head 220. Here, assuming that the elastic constant of the elastic body 206 is about 0.1 [N / m] and the amount of elastic deformation is about 1 [μm], the contact force of the probe with respect to the recording medium is about 10 ^−7. [N].

A position control signal from a position control circuit 213 controlled by a control computer 214 is received, and xyz is received.
The xyz stage 208 attached to the recording medium 203 is driven by the driving mechanism 207, and the probe 205 and the recording medium 203 move relatively three-dimensionally. The position of the probe 205 in the xy and z directions is adjusted with respect to the recording medium 203 so that the tip of the probe 204 is
The probe 205 is positioned so as to be brought into contact with a desired position on 3 at a desired contact force. In the recording / reproducing apparatus described above, the probe 2
When scanning 05, the tip of the probe 204 on the probe 205 always keeps in contact with the recording medium 203.

In such a contact scanning method, when scanning is performed while the tip of the probe 204 is in contact with the recording medium 203, even if the surface of the recording medium 203 has irregularities, the elastic body 2
In order to absorb this by the elastic deformation of 06, the probe 204
The contact force between the tip and the surface of the recording medium 203 is kept substantially constant, so that the tip of the probe 204 and the surface of the recording medium 203 can be prevented from being broken. Since this method does not require means such as a piezo element for positioning each probe in the z direction,
The configuration is not complicated, and it is particularly suitable for an apparatus having a plurality of probes. Further, since feedback control of the position of each probe 205 in the z direction with respect to the recording medium 203 is unnecessary, the probe 205
Can be scanned at high speed. A recording signal generated from the recording control circuit 211 controlled by the control computer 214 is changed to a changeover switch 209 switched to a recording system.
Is applied to the recording medium 203 from each probe 204. In this way, recording is locally performed on the portion of the recording layer 202 where the tip of the probe 204 contacts. in this way,
A minute portion recorded on the medium is hereinafter referred to as a dot.

As the recording layer 202 in the above-mentioned apparatus, a material whose current value changes when a voltage is applied is used. As a specific example, first, JP-A-63-16 / 1988
No. 1552, Japanese Unexamined Patent Publication No. 63-161553, and polyimide or SOAZ (bis-n-
LB film having an electric memory effect such as octylsquarylium azulene (= Langmuir-Blodget)
(a cumulative film of organic monomolecular films formed by the te method). This material changes the conductivity of the LB film (from OFF state to ON state) when a voltage higher than the threshold value (about 5 to 10 [V]) is applied between the probe, the LB film, and the substrate. The current flowing when a bias voltage (approximately 0.01 to 2 [V] is applied) increases. When this medium is used, the recorded dots have higher conductivity than the surroundings. As a specific example of 2, GeTe, GaSb,
An amorphous thin film material such as SnTe can be used. This material applies a voltage between the probe, the amorphous thin film material, and the substrate, and causes a phase transition from amorphous to crystalline by heat generated by a flowing current. As a result, the conductivity of the material changes, and the current flowing when a bias voltage for reproduction is applied increases. As a third specific example, Zn, W,
Oxidizing metal and semiconductor materials such as Si and GaAs may be used. When a voltage is applied between the probe and the oxidizable metal / semiconductor material, this material reacts with water adsorbed on the surface of the material or oxygen in the atmosphere by a flowing current to form an oxide film on the surface. For this reason, the contact resistance of the material surface changes, and the current flowing when a bias voltage is applied decreases. When this medium is used, the recorded dots have lower conductivity than the surroundings.

The reproduction of the dots recorded on the medium as described above is performed as follows. After the signal wiring from each probe 205 is switched to the reproduction system by the switch 209, the probe 20 is switched by the bias voltage applying means 210.
A bias voltage is applied between the substrate 4 and the substrate 201, and a current flowing therebetween is detected by the reproduction control circuit 212. Since a larger amount (or a smaller amount) of current flows in the dot portion on the recording medium 203 than in the unrecorded portion, the reproduction control circuit 212 detects this difference in current,
The signal is output to the control computer 214 as a reproduction signal.

The information recording / reproducing method of this embodiment will be described in more detail below. In this embodiment, data is recorded on a medium as follows. Each probe 301 is integrally formed as a probe unit by a micromachining technique (not shown). First, each probe 301 records information in a rectangular information recording area. This information recording area is hereinafter referred to as a data block (FIG. 3).
(A)). Each data block 330 is composed of linear data tracks 310 arranged in parallel at equal intervals (FIG. 3B). Each data track 310 is composed of data dots 320 arranged linearly (FIG. 3C). This data dot 320
In this example, track address information and data to be recorded are modulated and recorded. The track address is a number unique to each data track. The X axis is taken from left to right in the figure along the data track, and the Y axis is taken from top to bottom in the figure in a direction perpendicular thereto. Recording of information is performed by moving the probe unit to the recording start position and then scanning the probe unit while modulating the voltage applied to the probe for recording. The scanning of the probe unit is performed by alternately repeating scanning in the X direction and track movement in the Y direction, as shown in FIG. Although only one probe is shown in FIG. 4, all the probes actually scan on the medium in the same manner because all the probes are integrally formed as a probe unit. When the same probe unit is used at the time of recording and at the time of reproduction, all the tracks can be reproduced at the same time because the probe position does not shift.

The following describes a reproducing method according to the present invention when different probe heads are used for recording and reproducing. FIG. 1 shows the position of a probe as viewed from each data block when reproduction is performed using a multi-probe head different from that used for recording in the present embodiment. Although four probes are shown in the figure, the number of probes may be any number. dx0 to dx4 and dy0 to 4 represent displacements of the probes 0 to 4 from the reference position of each data block (in the figure, the upper left of each data block). For example, the maximum error of creating the probe tip position is ± 100n.
Assuming that there are m, the positions of the data blocks to be recorded vary by ± 100 nm at maximum in the XY directions on the medium. If the data block is reproduced by a probe head different from the one used at the time of recording, the position of the data block as viewed from the tip of the probe is at most ± 200 nm. In this embodiment, the regeneration when the probe is replaced is as follows. 1. Measurement of displacement of each probe The procedure is to reproduce information based on the displacement of each probe. The details will be described below. First, the displacement of each probe is measured in the following procedure. This measurement may be performed only when the probe or the medium is replaced.

FIG. 5 shows a flowchart of this procedure. 1. The probe unit is positioned in the Y direction so that all the probes fall within the range of the data block in the Y direction (FIG. 5A). This is determined from the assumed maximum process error. For example, as in the above-described example, the position of the data block as viewed from the tip of the probe is up to ± 20.
Assuming that the probe unit is shifted by 0 nm, the Y coordinate of the probe unit may be set within 200 nm from the upper and lower ends of the data block. 2. Move the probe unit to a position where all probes will be to the left of the beginning (left end) of the data track.
Position in the direction (FIG. 5 (2)). This is also 1. Similarly, it is obtained from the assumed maximum process error. 3. The probe unit is scanned in the X direction until all the probes will be on the right side of the data track (FIG. 5 (3)). 4. When a reproduction signal larger than a preset threshold value is detected in each probe, the reproduction signal is demodulated. Then, the shift amount of each probe is calculated (FIG. 5 (4)). Displacement d of probe n in X direction and Y direction
Xn and dYn are given by dXn = XPn dYn = YPn-TAn × T. Here, XPn: X coordinate of the data track reproduction start, YPn: Y coordinate of the probe unit, TA
n: a track address (a unique number of each data track, which increases by one from top to bottom in the figure) included in the demodulated signal, and T: an interval between data tracks. 5. When the reproduction signal has been demodulated by all the probes, the process ends. Otherwise, drive one step in the Y direction,
2. (FIG. 5 (5)). Here, it is assumed that the moving step in the Y direction is sufficiently smaller than the interval between the data tracks. In this embodiment, the data track interval is 20n
For m, the moving step was 4 nm.

The reproduction of information based on the displacement of each probe is performed in the following procedure. At the time of reproduction, a probe for reproduction, a reproduction start track address T
A, the number of tracks to be reproduced is specified in advance. Hereinafter, the displacement amounts dXn and dYn of the probes involved in the reproduction are described.
Of the maximum and minimum, dXmax and dX
min, dYmax, and dYmin, and the length of each data track is L. FIG. 6 shows a flowchart of this procedure. 1. Set the Y coordinate of the probe unit to (T × TA−dYma
x) (FIG. 6 (1)). By doing so, the probe which is shifted to the lowermost position (the probe having the largest dYn) among the probes involved in the reproduction is positioned in the Y direction so as to be on the extension of the reproduction start track. 2. The X coordinate of the probe unit is moved to the left side in the figure from -dXmax (FIG. 6 (2)). In this way, the positioning is performed in the X direction such that all the probes involved in the reproduction are located on the left side of the left end of the data track. 3. The probe unit is scanned in the X direction until the X coordinate of the probe unit exceeds L + dXmin (FIG. 6).
(3)). In this way, all the probes involved in the reproduction are scanned until the probe goes beyond the end (right end) of the data track. 4. 2. For each probe If a reproduction signal larger than a preset threshold value is detected during the scanning, the reproduction signal is demodulated. If the track address included in the demodulated signal is a track address for which reproduction is designated, both the track address and the demodulated data are recorded in the buffer memory (FIG. 6).
(4)). 5. If the probe that is shifted to the uppermost position (the probe with the smallest dYn) among the probes involved in the reproduction demodulates the signal, it means that all data belonging to the data track has been demodulated. From 1
The data reproduced for the data track is transferred (FIG. 6 (5)). 6. If all the data tracks to be reproduced have been reproduced, the process ends. Otherwise, drive one step in the Y direction and 2. Return to Here, the moving step in the Y direction is
It shall be sufficiently smaller than the track width. In this embodiment, the moving step is 4 nm for a track width of 20 nm. This setting ensures that all probes scan over the data track.

By reproducing information based on the above procedure, the SPM information recording / reproducing apparatus having a plurality of probes can reproduce information even when the probe unit is replaced. Therefore, even if the probe is damaged, the information can be reproduced by replacing the probe unit, so that the reliability of the information reproduction is improved, and when the medium is used as a removable medium, only the medium can be replaced. Since it is good, cost reduction can be achieved. Further, in the present embodiment, the order of outputting data is controlled using the buffer memory. However, if the order of extracting data does not need to be uniform, it is not necessary to use the buffer memory. Not even.

[Embodiment 2] An outline of a reproducing apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. A plurality of probes 505 are arranged such that a probe 504 provided at the tip comes into contact with the recording medium 503. The recording medium 503 is made of polycarbonate, and information is recorded as irregularities on the recording medium. therefore,
This recording medium 503 can be duplicated by a mold. The recording medium 503 has a freely exchangeable structure. In each probe 505, the probe 504 is connected to a piezo cantilever 50 whose electric resistance changes according to the amount of deflection.
6 supported. The plurality of probes 505 are integrally formed by a micromachining technique, and constitute a multi-probe head 520. Control computer 51
4 receives a position control signal from a position control circuit 513 controlled by
03 is driven, and the probe 505 and the recording medium 503 are relatively 3
Move in the dimension direction. The position of the probe 505 in the xy and z directions with respect to the recording medium 503 is adjusted, and the probe 504 is adjusted.
The probe 505 is positioned so that the leading end is in a desired position on the recording medium 503 and is brought into contact with a desired contact force.

When the probe 505 scans the recording medium 503 in the above reproducing apparatus, the tip of the probe 504 on the probe 505 always keeps in contact with the recording medium 503. Information recorded on the recording medium 503 as an uneven shape can be read as a change in electric resistance of the piezo cantilever 506. The change in the electric resistance of the piezo cantilever 506 is input to the control computer 514 through the reproduction control circuit 512. In this embodiment, by using the same reproducing method as that of the first embodiment, it is possible to reproduce information recorded on the recording medium 503 by using a multi-probe head different from that at the time of recording. By using the present invention, information can be reproduced from a recording medium on which information is recorded as unevenness using a plurality of probes. That is, it is possible to provide an SPM memory device having a plurality of probes and capable of mass copying of a recording medium.

[Embodiment 3] In this embodiment, an apparatus having exactly the same configuration as that of Embodiment 1 is used. However, recording medium 2
03 uses what can be erased. The record of information is
This is performed in exactly the same manner as in the first embodiment. When reproduction is performed using a probe different from that used for recording, information on the recording medium is reconstructed. To reconstruct information, first, the first embodiment
The displacement amount of each probe is measured in exactly the same manner as described above.
Then, the position of the information on the recording medium on the recording medium is moved based on the measured displacement amount of the probe. First, all information of a specific data block is read out to the buffer memory. Then, the data block on the recording medium is erased, and the content of the data block is re-recorded at a position shifted by the shift amount of each probe. When the capacity of the buffer memory is smaller than the data block, the data may be moved by dividing the buffer memory into several parts. If the data is reconstructed for all the probes, it is equivalent to performing reproduction using the same probe as that used for recording. As described above, by using the present invention, it is possible to provide an SPM memory device that can reproduce data at the same speed as when the same probe unit is used for recording and reproduction even when the probe unit is replaced.

[0023]

As described above, according to the present invention,
In an information recording / reproducing apparatus using a multi-probe head, an information reproducing method and apparatus capable of exchanging the multi-probe head, having high reliability, low cost of removable media, and utilizing a mass replication technique such as stamping are realized. can do. Further, according to the present invention, the scanning range of the scanning unit can be made wider than the range in which the data is recorded on the recording medium by the amount of the probe variation. Thus, the exchange of the multi-probe head becomes possible. Further, according to the present invention, when replacing the probe unit or the recording medium, the position of the data viewed from the probe by the data position reconstructing means based on the displacement amount of the probe measured by the measuring means. By reconstructing the position of the information recorded on the recording medium so as to eliminate the variation of the information, information that can be reproduced at the same speed as when using the same probe unit at the time of recording and at the time of reproduction A playback device can be realized.
According to the present invention, using the means for moving between data tracks,
By moving the probes in a movement step smaller than the interval between the data tracks, all the probes can scan over the data tracks. Also,
According to the present invention, when the scanning unit scans the probe unit relative to the recording medium, demodulation of the reproduction signal is performed only when the reproduction signal from the probe is equal to or greater than a predetermined threshold. Thus, it is possible to demodulate the reproduction signal of only the probe scanning the data track. Also, according to the present invention, the order in which data is reproduced is probed by configuring buffering means for temporarily storing demodulated information from the information demodulating means and transferring the demodulated information to the outside in the required order. Is prevented from being changed due to the variation of the data, and the data can be output in a required order. According to the present invention, the displacement of the probe is measured at the time of replacement of the probe unit or the recording medium by using the probe displacement measurement means, thereby minimizing the driving range of the driving means and achieving high-speed operation. Thus, an information reproducing apparatus capable of reproducing information quickly can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a positional relationship between data recorded on a medium and a plurality of probes according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of an SPM memory device and a control circuit according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating information on a recording medium and arrangement of probes according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating an operation locus of a probe according to the first embodiment of the present invention.

FIG. 5 is a flowchart at the time of measuring a probe position shift in the first embodiment of the present invention.

FIG. 6 is a flowchart at the time of reproducing information according to the first embodiment of the present invention.

FIG. 7 is a schematic diagram of an SPM memory device and a control circuit according to a second embodiment of the present invention.

[Explanation of symbols]

 100 to 104, 301, 401: Probe 110, 310: Data track 320: Data dot 130, 330, 430: Data block 340: Recording medium 490: Probe scanning locus 201: Substrate 202: Recording layer 203, 503: Recording medium 204 , 504: probe 205, 505: probe 206: elastic body 506: piezo cantilever 207, 507: xyz drive mechanism 208, 508: xyz drive stage 209: switch 210: bias applying means 211: recording control circuit 212, 512: Reproduction control circuit 213, 513: Position control circuit 214, 514: Control computer 220, 520: Multi-probe head

Claims (14)

[Claims] A probe unit having a plurality of probes; scanning means for relatively scanning the probe unit with respect to a recording medium; and a position caused by a variation in the plurality of probes in the probe unit caused by a probe creation error. Measuring means for measuring a shift amount, wherein a scanning range of the scanning means is configured to scan in a range wider by a position shift amount of the probe than a range in which data on the recording medium is recorded. An information reproducing apparatus characterized by being performed. 2. The scanning unit according to claim 1, wherein said scanning unit scans said probe unit relative to said recording medium in a direction parallel to a data track, and moves said probe unit to said data track with respect to said recording medium. 2. The information reproducing apparatus according to claim 1, further comprising: inter-data-track moving means which can move in a vertical direction in a moving step smaller than an interval between the data tracks. 3. The scanning unit demodulates a reproduction signal only when a reproduction signal from the probe is equal to or greater than a predetermined threshold when the probe unit relatively scans the recording medium. 3. The information reproducing apparatus according to claim 2, further comprising demodulation means. 4. An information reproducing apparatus according to claim 3, further comprising a buffering means for temporarily storing information demodulated by said demodulating means and transferring the information to an external device in a required order. 5. A probe unit having a plurality of probes, scanning means for relatively scanning the probe unit with respect to a erasable and re-recordable recording medium, and A measuring unit for measuring a displacement amount due to a variation in a plurality of probes; and a data position reconstructing unit for reconstructing a position of information recorded on the recording medium, and exchanging the probe unit or the recording medium. The information recorded on the recording medium so as to eliminate variations in the position of data viewed from the probe by the data position reconstructing means, based on the amount of displacement of the probe measured by the measuring means. An information reproducing apparatus characterized by reconfiguring the position of the information. 6. A scanning means for scanning the probe unit relative to the recording medium in a direction parallel to a data track, and the scanning means for moving the probe unit on the data track with respect to the recording medium. 6. The information reproducing apparatus according to claim 5, comprising: inter-data-track moving means that can move in a vertical direction in a moving step smaller than a distance between the data tracks. 7. When the scanning unit scans the probe unit relative to the recording medium, the scanning unit demodulates the reproduced signal only when the reproduced signal from the probe is equal to or greater than a predetermined threshold value. 7. The information reproducing apparatus according to claim 6, further comprising a demodulation unit. 8. An information reproducing apparatus according to claim 7, further comprising buffering means for temporarily storing information demodulated by said demodulating means and transferring the information to the outside in a required order. 9. An information reproducing method in which a probe unit having a plurality of probes is relatively scanned with respect to a recording medium to reproduce recorded information, wherein a variation in the plurality of probes in the probe unit caused by a probe creation error occurs. Measuring means for measuring the amount of displacement, when replacing the probe unit or the recording medium, a range wider than the range of data recorded on the recording medium by the amount of displacement of the probe. An information reproducing method, wherein a scanning unit is capable of scanning. 10. When the probe unit scans relative to the recording medium, the reproduction signal is demodulated only when the reproduction signal from the probe is equal to or greater than a predetermined threshold. The information reproducing method according to claim 9. 11. The information reproducing method according to claim 10, wherein information demodulated by demodulation of said reproduction signal is temporarily stored and transferred to the outside in a required order. 12. An information reproducing method in which a probe unit having a plurality of probes is relatively scanned with respect to a recording medium to reproduce recorded information. Measuring means for measuring a displacement amount due to a variation in a plurality of probes between the probe units, and when exchanging the probe unit or the recording medium, based on the displacement amount of the probe measured by the measuring means. An information reproducing method for reconstructing a position of information recorded on the recording medium so that the data position reconstructing means eliminates a variation in a position of data viewed from the probe. 13. When the probe unit scans relative to the recording medium, the reproduction signal is demodulated only when the reproduction signal from the probe is equal to or greater than a predetermined threshold. The information reproducing method according to claim 12. 14. The information reproducing method according to claim 13, wherein information demodulated by demodulation of said reproduction signal is temporarily stored and transferred to the outside in a required order.