JP2942014B2 - Recording and / or reproducing method and information recording carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording carrier having a high density and a large capacity, and a recording and / or recording medium for the information recording carrier.
Or, it relates to a reproduction method.

[0002]

2. Description of the Related Art In recent years, memory devices and memory systems have been used in a wide variety of applications, such as computers and related equipment, video disks, digital audio disks, and the like, and are at the core of the electronics industry.
Conventionally, magnetic memories and semiconductor memories have been the mainstream, but with the development of laser technology in recent years, optical memory devices using inexpensive and high-density recording media have appeared. But,
With the advance of computer use in home use and the information industry centering on images in the future, the realization of a memory device or method with a larger capacity and a smaller volume is desired.

On the other hand, in recent years, a scanning tunneling microscope (hereinafter, referred to as a “tunneling microscope”) capable of directly observing the electronic structure of surface atoms of a conductor has been proposed.
STM) was developed and → [G. Binnget
al. , Helvetica Physica Act
a. , 55.726 (1982)]. It has become possible to perform high-resolution measurement in real space irrespective of single crystal or amorphous.
The STM utilizes the fact that a tunnel current flows when a voltage is applied between a metal probe and a conductive material to approach a distance of about 1 nm. This current is very sensitive to a change in the distance between the two, and a surface image in real space can be drawn by operating the probe so as to keep the tunnel current constant. Measurement using STM is limited to conductive materials,
It has begun to be applied to the structural analysis of an insulating film formed thinly on the surface of a conductive material. Further, since the STM uses a method for detecting a minute current, it has an advantage that observation can be performed with low power without damaging the measurement material. Further, since it operates not only in an ultra-high vacuum but also in the air and in a solution and can be used for various materials, a wide range of applications is expected.

In particular, applications as a recording device for writing information at high resolution in a material and a reproducing device for reading information written at high resolution in a material have been advanced. As described above, in the apparatus to which the STM technique is applied, an advanced precision control technique is required to bring the probe electrode and the recording medium closer to about 1 nm.

[0005]

However, in the prior art applying the principle of the STM, it is necessary to precisely control the distance between the probe electrode and the surface of the recording medium in the order of nm. Until now, complicated control circuits and mechanisms were required.

The present invention provides a recording and / or reproducing method and an information recording carrier which make it easier and more reliable to control the distance between the probe and the recording medium during recording or reproduction, which is an application of the above-mentioned conventional example. For the purpose.

[0007]

According to the present invention, there is provided a method for recording and / or reproducing information on an information recording medium via a probe, comprising the steps of: An interval setting layer for setting an interval between the recording layer and the probe is provided, and information is recorded and / or reproduced on the recording layer via the probe with the interval setting layer interposed therebetween.

Further, the present invention relates to an information recording carrier on which information is recorded and / or reproduced via a probe facing a recording layer, wherein an interval for setting an interval between the recording layer and the probe on the recording layer. A setting layer is provided.

[0009]

FIG. 1 is a diagram showing an information recording / reproducing apparatus using a first embodiment of the present invention. In the drawing, reference numeral 1 denotes a tungsten probe electrode formed by an electropolishing method, 2 denotes an elastic support mechanism for supporting the probe electrode in an xy direction and supporting the probe electrode so as to be movable in a z direction, and 3 denotes a probe electrode formed by z.
This is a z-direction coarse movement mechanism that coarsely moves in the direction. Reference numeral 4 denotes a recording medium having a surface parallel to the xy plane. 40 is a smooth substrate obtained by cleaving mica, 41 is Au on the substrate 40
Is a recording layer in which eight layers of squarylium-bis-6-octylazulene (hereinafter abbreviated as SOAZ) having an electric memory effect are accumulated by the LB method, 43 is polyisobutyl methacrylate by the LB method This is an interval setting layer with one layer. Recording medium 4
Denotes a substrate 40, a base electrode 41, a recording layer 42, a spacing layer 4
3 is comprised. Reference numeral 5 denotes an xy direction scanning mechanism for operating the recording medium 4 in the xy directions. Reference numeral 6 denotes an interface for connecting the recording / reproducing apparatus to an external device. Write / read information, a status signal, a control signal of a recording / reproducing device, an address signal, and the like are exchanged between the interface 6 and the external device. Reference numeral 60 denotes a control circuit for centrally controlling the mutual operation between the blocks in the recording / reproducing apparatus, 61 a write / read circuit for writing / reading write / read information (data) in accordance with an instruction from the control circuit 60, and 62 a write / read circuit. Circuit 61
A voltage application circuit for applying a pulse voltage for writing data during recording and applying a read voltage during reproduction between the probe electrode 1 and the recording medium 4 in response to a command signal from This is a current amplifying circuit that amplifies a current flowing between the recording medium 4. 68 detects contact between the probe electrode 1 and the recording medium 4 from a sensor attached to the elastic support mechanism 3 described later,
This is a position detection circuit for detecting the scanning position of the probe electrode 1 in the xy direction on the recording medium 4 from the driving state of the direction scanning mechanism 5. Reference numeral 64 denotes a positioning circuit which determines the positions of the probe electrode 1 and the recording medium 4 based on signals from the current amplification circuit 63 and the position detection circuit 68 according to instructions from the control circuit 60 and the like.
A servo circuit for servo-controlling the positions of the probe electrode 1 and the recording medium 4 based on the servo signal from the positioning circuit 64;
Reference numeral 66 denotes a z-direction drive circuit that drives the z-direction coarse movement mechanism of the probe electrode 1 in accordance with a signal from the positioning circuit 64, and reference numeral 67 denotes an xy drive that drives the xy-direction scanning mechanism 5 on which the recording medium 4 is mounted in accordance with a signal from the servo circuit 65. It is a direction drive circuit.

The elastic support mechanism 2 will be described with reference to FIG. In the figure, 1 is a probe electrode obtained by sharpening tungsten having a diameter of 25 μm by electropolishing, and 20 is a length of 1 mm.
An elastic member made of Au foil having a width of 0.2 mm and a thickness of 10 μm,
Reference numeral 11 denotes an adhesive portion made of a conductive adhesive for fixing the probe electrode 1 and the elastic member 20. Reference numeral 21 denotes a base for fixing the end of the elastic member 20 on the side opposite to the probe electrode 1. Further, the base 21 is not shown. And the z-direction coarse movement mechanism. 22
Is a bending sensor for detecting the bending of the elastic member 20 from the distortion of the surface.

The operation of the invention device will be described.

Since the probe electrode 1 is separated to avoid collision with the recording medium 4 when the recording medium is installed, the two are brought close by the z-direction coarse movement mechanism 3. The procedure is z
The probe is driven until the deflection sensor 22 attached to the elastic support mechanism 2 drives the direction coarse movement mechanism 3 to detect contact between the probe electrode 1 and the recording medium 4 (determining that the elastic member 20 has been bent when the elastic member 20 is bent). This is performed by bringing the electrode 1 closer. At this time, the probe electrode 1 is pressed against the recording medium 4 by the elastic force caused by the elastic member 20 being bent. The distance between the tip of the probe electrode 1 and the recording layer 42 of the recording medium is determined by the distance setting layer 43, and the distance is about 1 n in the thickness of one layer of polyisobutyl methacrylate.
m. Here, while holding the z-direction coarse movement mechanism 3 and applying a bias voltage of 0.1 V from the voltage application circuit 62 between the probe electrode 1 and the base electrode 41 of the recording medium, the recording medium 4 is applied to the probe electrode 1. Is scanned using the xy-direction scanning mechanism 5, so that recording and reproduction can be performed while maintaining a constant distance between the probe electrode 1 and the base electrode 41 of the recording medium. When the read information was actually viewed in this state, no information was found. More specifically, the output value of the current amplifying circuit 63 obtained while scanning the recording medium 4 was 1 pA or less in terms of the current flowing between the probe electrode 1 and the base electrode 41 of the recording medium 4.

Recording is performed by applying a write voltage by a voltage application circuit 62 when the probe electrode 1 comes to the write position in the recording area while scanning the recording medium 4. This write voltage is a voltage sufficient for the recording layer 42 having the electric memory effect to change to the ON (low resistance) state. FIG. 3 (xz) shows the relationship between the probe electrode 1 and the recording medium 4 at this time.
7 is a recording bit (ON portion of the recording layer), 8
Is an arrow indicating the scanning direction of the recording medium 4 (x direction in this figure). The write timing and the like are controlled by the control circuit 6.
It depends on the control signal of 0. Recording is performed while moving the recording medium 4 in the x direction, and when recording for one column in the x direction is completed,
Similarly, printing is performed for one row in the x direction in the next row, shifted one step in the y direction. During scanning of the recording medium 4, a writing voltage is applied at each voltage application position on the recording medium 4. As a result, the recording bit 7 is formed.

The reproduction is performed when the recording medium 4 is recorded by using the xy direction scanning mechanism 5 while applying a read voltage of, for example, 0.1 V between the probe electrode 1 and the base electrode 41 of the recording medium by the voltage application circuit 62. Scanning is performed in a similar path, and the current amplification circuit 63 checks the change in current. The applied voltage is set to a sufficiently small value so that the recording layer 42 does not change the resistance state. The output value of the current amplifying circuit 63 obtained while actually scanning the recording medium 4 is converted into a current flowing between the probe electrode 1 and the base electrode 41 of the recording medium 4 to obtain a recording bit 7.
The position was 0.1 nA at the position, and the value at other positions was 1 pA or less. This current change becomes read information by the write / read circuit 61 and is transmitted to the host device through the interface 6. The read timing and the like depend on the control signal of the control circuit 60.

In both recording and reproduction, the distance between the tip of the probe electrode and the recording layer was accurately determined by the interval setting layer, and stable recording and reproduction could be performed. The dimensions of the recording bit were 90 nm in diameter.

Although the probe electrode used in this embodiment is obtained by electrolytically polishing a tungsten rod, a rod of platinum-rhodium or platinum-iridium may be subjected to electrolytic polishing or mechanical polishing.

FIG. 4 is a view showing another embodiment of the present invention, in which 1 is a probe electrode, 22 is a support on which a unit of two probe electrodes is attached,
Reference numeral 30 denotes a z-direction coarse movement mechanism (including a tilt mechanism) for moving the probe electrode 1 in the z-direction via the support, 23 denotes a carriage for moving the probe electrode 1 in the r-direction (radial direction of the recording medium), and 24 denotes a carriage. An r-direction drive mechanism for driving the carriage 23. Reference numeral 4 denotes a recording medium. Au is applied on a polished glass disk by a spatter method to form a base electrode, and then eight layers of SOAZ having an electric memory effect are accumulated by an LB method to form a recording layer.
It is provided as a one-layer interval setting layer by the method. 44 is a spindle for fixing and rotating the recording medium 4, 45 is a motor for rotating the spindle 44, and 46 is a belt for transmitting the rotation of the motor 45 to the spindle 44. As described above, in this embodiment, the recording medium is rotated, and information recording and reproduction are performed in the circumferential direction of the rotation. The blocks around the circuit are almost the same as those in all the embodiments, except that the control circuit 60 controls the start and stop of the rotation of the motor 45, and the recording voltage from the circuit 62 is applied by switching to two probe electrodes. And a switching device (not shown) for switching and amplifying signals from the two probe electrodes and transmitting the amplified signals to the circuit 61 is provided. Therefore, the coordinate system is r, θ, z with reference to the rotation center of the spindle 44 (see FIG. 6), and the probe electrode 1 according to the signal of the servo circuit 65 indicated by reference numeral 69. Carriage 23 with attached
The difference is that an r-direction drive circuit for generating a drive signal is provided in an r-direction drive mechanism for driving the r-direction in the r-direction (radial direction of rotation).

FIG. 5 shows the structure of the recording / reproducing apparatus according to the present embodiment.
1A and 1B are probe electrodes, 12A and 12B are Au extraction electrodes for extracting signals from the probe electrodes, 20A and 20B are 0.8 mm long and 0.1 mm thick An elastic member 21 made of Si having a thickness of 5 μm is a base for fixing to the support 22. Although not shown, sensors for detecting bending of the elastic members are formed on the elastic members 20A and 20B as in the first embodiment. Probe electrodes 1A and 1B and elastic member 20
A and 20B are the so-called micromechanics technologies →
[K. E. FIG. Petersen, Proc. IEEE7
0, 420 (1982)], so it is possible to accurately produce the same shape.

The operation of the apparatus according to the present invention will be described with reference to FIGS. First, the probe electrode 1 is separated to avoid collision with the recording medium 4. First, the motor 45 is driven, the spindle 44 is rotated, and the recording medium 4 is rotated. As shown in FIG. 6, the rotation direction 9 is a direction in which the fixed portion of the elastic member becomes upstream of rotation. When the rotation of the recording medium is stabilized, the sensors attached to the elastic members 20A and 20B until both the probe electrodes 1A and 1B detect contact with the recording medium, that is, the two deflection detection sensors detect the deflection together. Until then, the z-direction coarse movement mechanism (tilt mechanism) 30 is driven to bring the probe electrode close to the recording medium. At this time, the probe electrodes 1A and 1B are pressed against the recording medium 4 by the elastic force due to the elastic members 20A and 20B being bent, and the distance between the tips of the probe electrodes 1A and 1B and the recording layer of the recording medium is The thickness of one layer of polyisobutyl methacrylate is about 1 nm. Where z
Recording and reproduction can be performed by holding the direction coarse movement mechanism 3 and moving the probe electrode on the recording medium using the r-direction drive mechanism.

The recording / reproducing method is the same as in the above embodiment. FIG. 7 (θz sectional view) shows the relationship between the probe electrode 1A and the recording medium 4 at this time, where 7 is a recording bit (ON portion of the recording layer), and 9 is an arrow indicating the rotation direction of the recording medium 4. .

As described above, since the interval setting layer is composed of one layer of the LB film, the interval setting layer having a uniform thickness is applied to the recording medium with a strong force. Therefore, a stable distance between the tip of the probe electrode and the recording layer can be set and maintained over the entire recording region, and the probe has sufficient strength against contact with the probe.

As the material for the interval setting layer, polyisobutyl methacrylate was used in the embodiment, but other materials such as polymethyl methacrylate, polyethylene, polyvinyl chloride and polyisobutylene can also be used. Any material that can be formed into a film having a thickness of and has no electric memory effect can be used for the interval setting layer of the present invention.

The interval setting layer in both embodiments is set on the recording medium side, but may be set on the probe electrode side (FIG. 8).
reference). Further, although the SOAZ is taken as an example of the recording layer, other materials having an electric memory effect can be used. The apparatus is a recording / reproducing apparatus, but may be an apparatus having only one of recording and reproducing functions.

[0024]

As described above, according to the present invention, the distance between the probe and the recording medium can be set without requiring a complicated circuit and more accurately, and the recording and reproduction of information can be performed easily and reliably. became.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a probe electrode and an elastic member according to the first embodiment.

FIG. 3 is an explanatory sectional view showing a positional relationship between a probe electrode and a recording medium during recording.

FIG. 4 is a schematic block diagram of a recording / reproducing apparatus using another embodiment of the present invention.

FIG. 5 is a perspective view of two probe electrodes and an elastic member.

FIG. 6 is a perspective view showing a positional relationship between a disk-shaped recording medium and two elastic members.

FIG. 7 is a cross-sectional view showing a positional relationship between a probe electrode and a recording medium during recording and reproduction.

FIG. 8 is an explanatory view of still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Probe electrode 2 Elastic support mechanism 3 Z direction coarse movement mechanism 4 Recording medium 5 XY direction scanning mechanism 6 Interface 20 Elastic member 22 Flexure sensor 41 Base electrode 42 Recording layer 43 Interval setting layer 62 Voltage application circuit 63 Current amplification circuit

Continuation of the front page (72) Kunihiro Sakai, Incorporated Canon Inc., 3-30-2 Shimomaruko, Ota-ku, Tokyo (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 9/00 G11B 9 / 04

Claims (6)

(57) [Claims] An interval setting layer for setting an interval between a recording layer and a probe between a recording layer of the information recording medium and a probe in a method for recording and / or reproducing information on an information recording medium via a probe. Information is recorded on the recording layer via the probe while sandwiching the interval setting layer, and / or
Or an information recording and / or reproducing method characterized by reproducing. 2. The recording and / or reproducing method according to claim 1, wherein the interval setting layer is provided on a recording layer of the information recording medium. 3. The recording and / or reproducing method according to claim 1, wherein the interval setting layer is an LB film. 4. The recording and / or reproducing method according to claim 1, wherein the thickness of the interval setting layer is 1 nm. 5. The recording and / or reproducing method according to claim 1, wherein recording and / or reproducing are performed while operating said information recording medium by said probe while said probe is pressed against said interval setting layer. Playback method. 6. An information recording carrier on and / or from which information is recorded and / or reproduced via a probe facing a recording layer, wherein an interval setting layer for setting an interval between the recording layer and the probe is provided on the recording layer. An information recording carrier, characterized by being provided.