WO2011027406A1

WO2011027406A1 - Method for reproduction by information recording reproduction device

Info

Publication number: WO2011027406A1
Application number: PCT/JP2009/004393
Authority: WO
Inventors: 冨澤泰; 中村博昭
Original assignee: 株式会社東芝
Priority date: 2009-09-04
Filing date: 2009-09-04
Publication date: 2011-03-10

Abstract

Provided is a method for reproduction by an information recording/reproduction device including a probe array (90) having a plurality of probes (80) for reproducing information and a recording medium (20) for recording a plurality of recording bits by the probes (80). The method uses the multi-probe and includes: a step of relatively scanning the probe array (90) in one (first) direction with respect to the recording medium (20); a step of relatively moving the probe array (90) in the other (second) direction which orthogonally intersects the first direction; and a step of reading out a region greater than the region where the recording bits are recorded

Description

Reproduction method of information recording / reproducing apparatus

The present invention relates to a reproducing method of an information recording / reproducing apparatus using a multi-probe.

In recent years, with the development of computer and Internet technologies, the amount of information of digital data and digital content handled by users has increased dramatically. Along with this, the increase in the capacity of file memory devices for each user to store data locally is progressing rapidly, and it is predicted that the need for an increase in capacity will continue to increase. However, despite these backgrounds, magnetic disk devices (HDD (Hard Disc Drive)) and flash memory, which are currently mainstream file memory devices, are said to reach the theoretical limit of recording density in the near future. .

From the above situation, there is a strong demand for the development of a completely new file memory storage device that can constantly increase the storage capacity even after the capacity of current recording devices reaches its limit. One of the very promising solutions to this requirement is an information recording / reproducing apparatus using a multi-probe constructed mainly using MEMS (Micro Electro Mechanical Systems) technology.

In US Patent Application Publication No. 2006/0291271, as an example of an information recording / reproducing apparatus using a multi-probe, a probe array in which a plurality of probes for reading and writing are arranged in an array is used. Have disclosed that a positioning signal is embedded in an area to be scanned.

However, if the relative positional relationship between the probes deviates, the recorded bits that were originally written by multiple probes cannot be read at the same time, so the work of reading out information while positioning one by one for each probe. It becomes necessary and the access speed is extremely reduced.

US Patent Application Publication No. 2006/0291271

Therefore, the present invention provides a reproducing method for an information recording / reproducing apparatus using a multi-probe capable of reproducing accurately in a short time.

An information recording / reproducing apparatus reproducing method using a multi-probe according to the present invention includes an information recording apparatus comprising: a probe array having a plurality of probes for reproducing information; and a recording medium on which a plurality of recording bits are recorded by the probes. A reproducing method of a reproducing apparatus, wherein the probe array is scanned relative to the recording medium in one direction, moved relative to another direction perpendicular to the one direction, and the recording bit is recorded. And a step of reading a wider area.

According to the present invention, it is possible to provide an information reproduction method using a multi-probe that can be reproduced in a short time.

The figure for demonstrating the information recording / reproducing apparatus which concerns on 1st Embodiment. The figure for demonstrating the 1st Example form. The figure for demonstrating the 1st Example form. The figure for demonstrating the 1st Example form. The figure for demonstrating the 1st Example form. The figure for demonstrating the 1st Example form. The figure for demonstrating the 1st Example form. The figure for demonstrating the 1st Example form. The figure for demonstrating an Example. The figure for demonstrating a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, the same reference numerals denote the same parts, and duplicate descriptions are omitted.

(First embodiment)
FIG. 1 illustrates an information recording / reproducing apparatus using a multi-probe according to the first embodiment of the present invention.

In the information recording / reproducing apparatus using the multi-probe according to the present embodiment, the recording medium 20 is provided on the stage 10.

The stage 10 includes an X-axis actuator 30 that moves the recording medium 20 in the X-axis direction and a Y-axis actuator 40 that moves the recording medium 20 in the Y-axis direction. At this time, the displacement of the entire stage 10 can be read out by an encoder that detects the position. As the encoder, a MEMS electrostatic capacitance sensor using a comb-tooth structure, an interferometer using a laser beam, a Doppler type speedometer, an LVDT (Linear Variable Differential Transformer), or the like can be used.

The recording medium 20 uses a recording layer 60 laminated on an electrode layer 50 as shown in FIG. A protective layer 70 may be further stacked on the recording layer 60.

As a recording principle in this embodiment, the principle that recording / reproduction can be performed by energizing or applying voltage to the probe 80, that is, ferroelectric recording (FeRAM principle), phase change recording (PRAM principle), resistance change. Various means such as recording (the principle of ReRAM) can be applied. For example, the material of the recording layer 60 may be a ferroelectric material such as PZT (PbZrTiO) or LiTaO for ferroelectric recording, a material exhibiting phase change characteristics such as GST (GeSbTe) for phase change recording, or a resistance. In the case of change recording, a material showing a giant resistance change characteristic such as NiO or TiO can be used. The probe 80 and the stage 10 are controlled by the control unit.

Furthermore, the electrode layer 50 can be made of a conductive material such as Ti or Pt, and the protective layer 70 can be made of an abrasion resistant material such as DLC (Diamond Like Carbon).

Further, in the information recording / reproducing apparatus using the multi-probe according to the present embodiment, a plurality of probes 80 are arranged in an array to constitute a probe array 90. An electrode or the like is disposed at the tip of each probe 80 so that information can be read and written through the tip of the probe 80.

The probe 80 may have a needle-like tip with a protrusion. For example, the probe 80 made of Si and coated with Rh (rhodium) can be used.

Next, the operation principle of the recording / reproducing apparatus using the multi-probe according to this embodiment will be described.

In the recording / reproducing apparatus using the multi-probe according to the present embodiment, the X-axis actuator 30 and the Y-axis actuator 40 provided on the stage 10 operate in the X-axis direction and the Y-axis direction, respectively, so that the probe array 90 is moved. The constituting probe 80 performs recording / reproduction on the recording medium 20. That is, the plurality of probes 80 provided in the probe array 90 perform recording and reproduction by operating the stage 10 while being fixed to the probe array 90. Hereinafter, the case of recording / reproducing using one probe 80 constituting the probe array 90 will be described. The other probes 80 perform the same operation.

When recording on the recording medium 20, the probe 80 is scanned in the X direction (scan direction) while flowing current (in the direction of the arrow 90), and after recording to some extent, the probe 80 is bitted in the Y direction (feed direction). Recording is performed by feeding at a pitch (in the direction of arrow 100) and scanning again in the X direction. Note that the X direction and the Y direction are orthogonal to each other.

On the other hand, the recording medium 20 can selectively switch between the high resistance state and the low resistance state according to the voltage applied between the electrode layer 50 and the probe 80, as in the principle of ReRAM (Resistive Random Access Memory). It is recorded as bit-like recording bits. Here, the ReRAM method will be described as an example.

The probe 80 can freely form fine recording bits by performing positioning control with an accuracy of the order of 0.1 nm to 1 nm.

Also, when the positioning control is performed with this accuracy, the size of the recording bit is 1 nm to 50 nm. The interval between the recording bits is 1 nm to 100 nm in the X direction and 1 nm to 100 nm in the Y direction.

FIG. 3 is a schematic view showing a state in which recording is performed on the surface of the recording medium 20 using the probe 80. As shown in FIG. 3, the upper direction on the paper is the Y direction (feeding direction), and the direction perpendicular to the Y direction is the X direction (scanning direction). The X direction and the Y direction are orthogonal to each other.

Black or white is a recording bit, and spots recorded in a bit shape are arranged in a grid in the area recorded as described above. For example, black is 1 in the low resistance state (with recording), and white is 0 in the high resistance state (no recording).

In the present embodiment, the recording bit includes a recording bit in which user information is recorded and a recording bit for detecting a recording position. That is, as shown in FIG. 3, two edge pattern areas 95 are provided with a recording bit area in which information is recorded interposed therebetween. Using these two areas 95 as a reference, an area where information recording bits are recorded can be specified. At this time, in the area 95, for example, one row of black data is recorded in one row. By doing so, it is possible to read the area where the information is recorded accurately.

FIG. 4 is a flowchart for explaining the process of reading (reproducing) the bits recorded on the recording medium 20.

FIG. 5 is a schematic diagram showing the reading operation of the probe 80.

In step S10, first, the probe 80 is moved to the reading position 110 as shown in FIG. Next, the probe 80 is scanned from the reading position 110 in the X direction to the end of the scanning area 120, and then sent from the reading position 110 at a bit pitch in the Y direction (arrow 100), and again in the X direction in the scanning area 120 on the reading position 110 side. Scan to the edge. Such an operation is repeated until the entire scan area 120 is read. The scan area 120 is an area scanned when the probe 80 performs recording / reproduction.

FIG. 10 shows a conceptual diagram during recording using a conventional probe array.

FIG. 10 (a) shows a diagram during recording, and FIG. 10 (b) shows a diagram during reproduction.

FIG. 10 shows two

probes

81 and 82 among a plurality of probes 80 constituting the probe array 90.

As shown in FIG. 10A, when the stage 10 is operated, the two

probes

81 and 82 simultaneously record on the recording medium 20.

However, the relative positional relationship between the probe array 90 and the recording medium 20 when thermal expansion of the recording medium 20 or the like occurs due to a change in environmental temperature or when the recording medium 20 or the like rotates due to aging fatigue, external impact, or the like. Will shift.

For this reason, as shown in FIG. 10B, it is difficult to accurately reproduce the bits recorded on the recording medium 20 by all the probes 80 provided in all the probe arrays 90. FIG. 10B shows a state in which the probe 82 is deviated from the recording state.

Therefore, in this embodiment, the probe 80 is moved so that the scan area 120 can be read over a wider range than the recording bit. For example, with respect to the bit pitch interval in the Y direction during recording, scanning is performed at a distance of 1 to 1.2 times in the X direction and the Y direction from the position of the recording bit recorded first.

By doing so, it is possible to read out even when the position of the recording bit is different from that at the time of reproduction due to the thermal expansion or the influence of the rotation of the stage 10.

It should be noted that the wider the scan area 120 from which reading is performed, the greater the allowable amount for deviation due to thermal expansion and rotation of the stage 10. However, the larger the scan area 120, the lower the ratio of the area where user information can be recorded to the area where recording bits of the recording medium 20 can be recorded. Considering that the ratio (format efficiency) in which user information is recorded with respect to the entire area of the disk in a hard disk drive, which is a typical information recording apparatus at present, is about 80%, this embodiment also shows this. It is desirable that the proportions be equal. Therefore, it is desirable to keep the ratio of the scan area at the time of reading to the area recorded first at about 1.2 times at the maximum.

In step S20, the recorded bit is read while scanning the probe 80 in the X direction.

In step S30, it is determined whether or not the entire reading range has been scanned. Whether or not the probe 80 has moved in the X and Y directions by the amount of the set scan area 120 from the reading position 110 is determined based on the reading value from the encoder that detects the position of the stage 10.

In step S40, the probe 80 is moved in the Y direction by the feed pitch. The operation of the probe 80 at the time of reading is the same as that at the time of recording, but the feature is that the bit pitch interval in the Y direction is narrower than the bit pitch interval at the time of recording. Specifically, the bit pitch in the Y direction during reproduction is not more than one-third of the bit pitch in the Y direction during recording.

By doing in this way, the feature point of the recording bit can be captured and read out, so that it can be read without missing.

In step S50, a two-dimensional image is constructed based on the read recording bits. This two-dimensional image shows a difference in resistance value read by the probe 80. For example, with a certain resistance value as a boundary, a low resistance portion is represented in black, and a high resistance portion is represented in white. The low resistance may be expressed in white and the high resistance may be expressed in black.

As a result of reading in this manner, the obtained two-dimensional image appears as a two-dimensional image scanned in the X direction as shown in FIG. A line in the X direction indicates a scan locus on the scan area 120 in which a plurality of recording bits are recorded. Since the interval of the bit pitch in the Y direction during reproduction is narrower than the interval of the bit pitch in the Y direction during recording, one recorded bit is formed by a plurality of scanned lines.

In step S60, a recording bit area in which information is recorded is detected from the area 95 in which the edge pattern of the two-dimensional image obtained by reading in step S50 is formed. That is, an area sandwiched between the areas 95 is a recording bit area in which information is recorded. Thereby, even if the step S50 has a deviation from the actual scanning direction, the recorded bit can be read accurately.

In step S70, squares are applied to the recording bits detected in step S60. Specifically, as shown in FIG. 7, a grid is applied to the recording bits 130 so that the recording bits 130 are divided into 3 × 3 9 divisions for one recording bit 130, and this is converted into an image. Applies to the whole.

In step S80, the number of black paint in the squares obtained by dividing the recording bit 130 into nine is counted. In addition, when a white portion is a recording area, the white portion may be counted.

In step S90, as shown in FIG. 8, if the number of black squares in a 3 × 3 square obtained by dividing the recording bit 130 into nine is 4.5 squares or more, it is determined that the recording bit 130 exists. The recording bit 130 is determined to be 1 (recorded) (step S110). If less than 4.5 squares, it is determined that the recording bit 130 does not exist, and this recording bit 130 is determined to be 0 (no recording) (step S100).

In step S120, based on steps S100 and S110, the patterns of 0 and 1 of the originally recorded recording bits are reconstructed.

In this way, when positioning the probe 80 with respect to the stage 10 at the time of reading, a two-dimensional image in which a position error has occurred due to externally applied vibration disturbance or electrical disturbance due to encoder noise or the like is obtained. It is possible to correct and restore the recorded bits with high accuracy.

In this example, the size of 3 × 3 squares is taken as an example for simplicity, but the number of squares can be freely set according to the actual recording bit size, the margin size between recording bits, the relationship between the feed pitch and the recording bit pitch, and the like. Can be changed. Similarly, the threshold value of 4.5 can be changed accordingly. Further, in this embodiment, all squares in the 3 × 3 square are counted equally as 1. However, for example, the central square in the 3 × 3 square is counted as 2, and a weighted determination is made. You can also.

Example 1
The recording bit was corrected using the invention according to the first embodiment.

FIG. 9 shows how many errors occur with respect to the correction of the recording bit pattern generated at random by using the method of steps S60 to S110 described in the first embodiment to correct the recording bit. FIG. The horizontal axis indicates the X direction, and the vertical axis indicates the Y direction.

FIG. 9A is a diagram showing randomly generated recording bit patterns. FIG. 9B is a diagram after correcting the recording bit. FIG. 9C shows how many read errors have occurred with respect to the original recording bit pattern.

In the present embodiment, for 400 recording bits recorded in an area of 200 nm in the X direction and 200 nm in the Y direction with an interval of 5 nm in the X direction and an interval of 20 nm in the Y direction, a position error caused in probe positioning when reading the recording bits. Was 0.5 nm.

As shown in FIG. 9C, among 400 bits, the number of read errors was 3 (outlined portion). From this, it can be seen that the recorded bits can be accurately restored.

10 ... Stage, 20 ... Recording medium, 30 ... X axis actuator, 40 ... Y axis actuator, 50 ... Electrode layer, 60 ... Oxide layer, 80 ... Probe, 90 ... Probe array, 95 ... Area, 100 ... Arrow, 110 … Reading position, 120… scan area, 130… recording bit

Claims

A reproduction method for an information recording / reproducing apparatus comprising a probe array comprising a plurality of probes for reproducing information and a recording medium on which a plurality of recording bits are recorded by the probes,
Scanning the probe array relative to the recording medium in one direction, moving the probe array relative to another direction orthogonal to the one direction, and reading a region wider than the region where the recording bits are recorded;
A reproducing method for an information recording / reproducing apparatus comprising:
Scanning the probe array relative to the recording medium in the one direction, moving the probe array in the other direction, reading a region wider than a region where the recording bits are recorded, and forming a two-dimensional image;
Applying a grid to the two-dimensional image;
Counting the number of recorded squares to detect and reproduce the recording bits;
The reproducing method of the information recording / reproducing apparatus according to claim 1, further comprising:
2. The reproducing method of the information recording / reproducing apparatus according to claim 1, wherein all the recording bits at both ends of the recording area are recorded so as to be in either a high resistance state or a low resistance state.
The information recording according to claim 1, wherein a distance that the probe moves in the other direction during the reproduction is equal to or less than one third of a distance that the probe moves in the other direction during the recording. A playback method of a playback device.