JP3078141B2 - Recording device and recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus and a recording / reproducing apparatus.

[0002]

2. Description of the Related Art At present, as a recording method for recording bit information, there are a magnetic recording method using a magnetic tape or a magnetic disk, and an electric recording method using a semiconductor element. In recent years, with the increase in the amount of information to be recorded, there has been a strong demand for a large capacity, a high speed, and a low error rate.

Under these circumstances, an organic thin film (for example, a thin film of a π-electron organic compound or a chalcogen compound) has a metal-organic insulating film-metal structure sandwiched between metal electrodes, and has a voltage-current (Hereinafter referred to as "MIM element") which has a memory effect on the switching characteristics of JP-A-63-096956 have been developed. In such an MIM element, the conductivity of the element can be reversibly changed by applying an appropriate pulse voltage between the metal electrodes. Therefore, information can be recorded on the MIM element by utilizing this switching phenomenon. In addition, the switching speed is very high in this switching phenomenon.

On the other hand, a scanning tunneling microscope (STM) capable of observing the surface of a substance at an atomic order of resolution has been developed, and real-space observation at the atomic and molecular levels has become possible (G. Binning et al., Phys. Rev. Lett, 49, 57,
1982). Scanning tunneling microscopes control the tip-to-sample distance while controlling the distance between the tip and the sample so that the value of the tunnel current flowing between the tip of the probe electrode (tip) and the conductive sample is constant. Scans two-dimensionally along the surface of the sample, and obtains information on the electron cloud on the surface of the sample and the shape of the sample from the control signal that controls the distance between the tip and the sample.
Observed at

If the principle of such a scanning tunneling microscope is applied, it is possible to perform high-density recording and reproduction on the order of atoms. For example, Japanese Patent Application Laid-Open No. 61-80
In the recording / reproducing apparatus disclosed in Japanese Patent Publication No. 536, information is recorded by removing atomic particles adsorbed on the surface of the recording medium by an electron beam or the like, and the recorded information is reproduced by a scanning tunnel microscope. I have. Further, in the recording / reproducing device disclosed in US Pat. No. 4,575,822, a tunnel current flowing between the tip and the surface of the recording medium is used to reduce the dielectric material formed on the surface of the recording medium. By injecting charge,
Records information. Further, there has been proposed a method of recording information by causing physical or magnetic collapse of a recording medium using a laser beam, an electron beam, a particle beam, or the like.

A recording / reproducing method has been proposed in which a thin film layer made of a material having a memory effect on the switching characteristics of voltage and current is used as a recording layer, and recording and reproduction are performed using the principle of a scanning tunneling microscope. (JP-A-63-161552 and JP-A-63-1).
No. 61553). According to this recording / reproducing method, when the recording bit size is 10 nm, 10 ¹² bits /
Large-capacity recording and reproduction as large as cm ² is possible. For example, as shown in FIG. 6, the recording / reproducing apparatus 600 according to this recording / reproducing method includes a recording medium 601, a recording medium stage 610, a coarse movement mechanism 611, an XY direction coarse movement control circuit 612, and a Z direction coarse movement A control circuit 613, a probe electrode 614, an XY direction fine movement mechanism 615, a Z direction fine movement mechanism 616, an XY direction fine movement control circuit 617, a Z direction fine movement control circuit 618, and a current amplifier 619.
, A microcomputer 620 and a first servo circuit 62
1, a second servo circuit 622, and a power supply 623. Each component of the recording / reproducing device 600 will be described in detail below.

(1) Recording Medium 601 As shown in FIG.
It comprises a substrate electrode 603 formed on 602 and a recording layer 604 formed on the substrate electrode 603. Here, the recording layer 604
Is a thin film layer made of a material having a memory effect on switching characteristics of voltage and current, and constitutes an MIM element having a metal-organic insulating film-metal structure together with the probe electrode 610 and the substrate electrode 603.

(2) Recording medium stage 610, coarse movement mechanism 61
1. XY coarse movement control circuit 612 and Z coarse movement control circuit 613 The recording medium stage 610 has a recording medium 601 mounted thereon. The coarse movement mechanism 611 moves the recording medium 601 in the illustrated X-axis direction, Y-axis direction, and Z-axis direction by coarsely moving the recording medium stage 610 in the illustrated X-axis direction, Y-axis direction, and Z-axis direction, respectively. It is to let. X
The Y-direction coarse control circuit 612 includes a microcomputer 620
And drives the coarse movement mechanism 611 in the X-axis direction and the Y-axis direction in the drawing. The Z-direction coarse movement control circuit 613 drives the coarse movement mechanism 611 in the illustrated Z-axis direction in accordance with a coarse movement control signal sent from the first servo circuit 621.

(3) Probe electrode 614, XY direction fine movement mechanism 615, Z direction fine movement mechanism 616, XY direction fine movement control circuit 61
7 and Z direction fine movement control circuit 618 The probe electrode 614 is provided to face the recording medium 601. The XY direction fine movement mechanism 615 makes the probe electrode 614 two-dimensionally scan the recording medium 601 by finely moving the probe electrode 614 in the illustrated X-axis direction and the Y-axis direction. The Z-direction fine movement mechanism 616 finely moves the probe electrode 614 in the illustrated Z-axis direction,
This is for finely adjusting the distance between the probe electrode 614 and the recording medium 601. The XY-direction fine movement control circuit 617 is controlled by the microcomputer 620 to drive the XY-direction fine movement mechanism 615 in the X-axis direction and the Y-axis direction, respectively. The Z-direction fine movement control circuit 618 drives the Z-direction fine movement mechanism 616 in the illustrated Z-axis direction in accordance with the fine movement control signal sent from the second servo circuit 622.

(4) Current amplifier 619, microcomputer 620, first servo circuit 621, second servo circuit 62
2 and the power supply 623. The current amplifier 619 amplifies the current flowing between the probe electrode 614 and the recording medium 601 to a microcomputer 620.
, A first servo circuit 621 and a second servo circuit 622
Respectively. First servo circuit 621
Is the value of the current sent from the current amplifier 619 and the probe electrode 61 sent from the microcomputer 620.
Coarse movement control for coarsely controlling the distance between the probe electrode 614 and the recording medium 601 by comparing a first current set value for keeping the distance between the probe electrode 614 and the recording layer 604 at a predetermined distance. The signal is output to the Z-direction coarse movement control circuit 613. Second
The servo circuit 622 includes a second value for keeping the distance between the probe electrode 614 and the recording layer 604 sent from the microcomputer 620 and the current value sent from the current amplifier 619 at a predetermined distance. This is to output a fine movement control signal for finely controlling the distance between the probe electrode 614 and the recording medium 601 to the Z direction fine movement control circuit 618 by comparing the current setting value. The power supply 623 applies a recording bias voltage and a recording pulse voltage between the recording medium 601 and the probe electrode 614 at the time of recording, applies a reproducing bias voltage at the time of reproduction, and applies an erasing bias voltage and an erasing voltage at the time of erasing. A pulse voltage is applied. The microcomputer 620 controls the XY coarse movement control circuit 612, the XY fine movement control circuit 617, and the power supply 623, respectively, and also stores the first current set value and the second current set value described above in the first servo circuit 621. And the second servo circuit 622
Respectively.

Next, the operation of the recording / reproducing apparatus 600 during recording and reproduction will be described.

At the time of recording, the power supply 623 is controlled by the microcomputer 620, and
A predetermined bias voltage is applied to one substrate electrode 603.
As a result, a predetermined bias voltage is applied between the probe electrode 614 and the substrate electrode 603 of the recording medium 601. At this time, the current detected at the probe electrode 614 (ie,
Current flowing between probe electrode 614 and substrate electrode 603)
Is amplified by the current amplifier 619, and then sent to the microcomputer 620, the first servo circuit 621, and the second servo circuit 622, respectively.

In the first servo circuit 621, the current amplifier 61
9 The value of the current sent from
0 is compared with a first current set value sent from the first current set value, and a coarse movement control signal for coarsely controlling the distance between the probe electrode 614 and the recording layer 604 is set so that the two values become the same.
Output to the direction coarse movement control circuit 613. The Z-direction coarse motion control circuit 613 generates a coarse motion mechanism 611 based on the coarse motion control signal.
Is generated in the Z-axis direction shown in FIG.
Output to 611. Thereby, the distance between the probe electrode 614 and the recording layer 604 is roughly adjusted. In the second servo circuit 622, the value of the current sent from the current amplifier 619 is compared with the second set current value sent from the microcomputer 620, so that the two values are the same. A fine movement control signal for finely controlling the distance between the probe electrode 614 and the recording layer 604 is supplied to the Z-direction fine movement control circuit 618.
Is output to The Z-direction fine movement control circuit 618 generates a signal for driving the Z-direction fine movement mechanism 615 in the illustrated Z-axis direction based on the fine movement control signal, and outputs the signal to the Z-direction fine movement mechanism 615. As a result, the probe electrode 614 and the recording layer 604
Is finely adjusted to maintain a predetermined distance.

The XY direction coarse movement control circuit 612 generates a signal for driving the coarse movement mechanism 611 in the illustrated X-axis direction and the Y-axis direction based on a command from the microcomputer 620, and outputs the signal to the coarse movement mechanism 611. You. In the XY direction fine movement control circuit 617, signals for driving the XY direction fine movement mechanism 615 in the illustrated X-axis direction and Y-axis direction based on the instruction from the microcomputer 620 are generated and output to the XY direction fine movement mechanism 615. You. Thus, the probe electrode 614 is scanned to the recording position on the recording medium 601.

In the power supply 623, the microcomputer 620
, A recording bias voltage and a recording pulse voltage are generated. The recording bias voltage and the recording pulse voltage are applied to the recording layer 604 via the substrate electrode 602 of the recording medium 601. By locally changing the conductivity of the portion of the recording layer 604 to which the recording pulse voltage is applied, a recording bit is formed on the recording layer 604.

At the time of reproduction, the probe electrode 614 is scanned to the reproduction position of the recording medium 601 in the same manner as at the time of recording. Thereafter, the power supply 623 generates a reproducing bias voltage. The reproduction bias voltage is applied to the substrate electrode of the recording medium 601.
603 is applied to the recording layer 604. At this time, after a current flowing between the recording layer 604 and the substrate electrode 603 is amplified by the current amplifier 619, the microcomputer 62
Sent to 0. In the microcomputer 620, the conductivity of the recording layer 604 is obtained from the value of the sent current.
Since the presence or absence of a recording bit can be determined from the obtained value of the conductivity, the recorded information can be reproduced.

[0017]

However, in the above-mentioned conventional recording / reproducing apparatus 600, even when a recording pulse voltage is applied to the recording medium 601 in order to record information, the non-uniformity of the recording layer 604 is not increased. Therefore, there is a problem that a recording error occurs such that the conductivity does not change.

An object of the present invention is to provide a recording apparatus and a recording / reproducing apparatus which can reliably record information on a recording medium whose conductivity changes by applying a voltage.

[0019]

A first recording apparatus according to the present invention comprises a first electrode, a second electrode, and a voltage control device provided between the first electrode and the second electrode. A recording medium including a recording layer whose conductivity is changed by application; and voltage applying means for applying a recording voltage between the first electrode and the second electrode. In a recording apparatus for recording information by applying the recording voltage between one electrode and the second electrode, at least one of at the time of the application of the recording voltage and after the application of the recording voltage. 1
Current detecting means for detecting a current flowing between the electrode and the second electrode, and determining whether or not the information is accurately recorded by the value of the current detected by the current detecting means, And determining means for sending a command to the voltage applying means to apply the recording voltage again between the first electrode and the second electrode when it is determined that the information has not been accurately recorded. .

According to the first recording / reproducing apparatus of the present invention, the first electrode, the second electrode, and the electric conductivity provided between the first electrode and the second electrode, which are provided between the first electrode and the second electrode, have a conductivity. A recording medium including a changing recording layer; and voltage applying means for applying a recording voltage and a reproducing voltage between the first electrode and the second electrode, respectively. The recording voltage is applied between the first electrode and the second electrode to record information, and the reproducing voltage is applied between the first electrode and the second electrode from the voltage applying means. In a recording / reproducing apparatus for reproducing a recorded information by applying a voltage, at least one of the first electrode and the second electrode at the time of applying the recording voltage and after applying the recording voltage. Current detecting means for detecting a current flowing therebetween, and the current detecting means It is determined whether or not the information has been accurately recorded based on the value of the detected current. When it is determined that the information has not been accurately recorded, the recording voltage is changed to the first electrode and the second electrode. Determination means for sending a command to the voltage application means to apply the voltage again between the electrodes.

The second recording apparatus of the present invention comprises a first electrode group provided in parallel with each other, a second electrode group provided in parallel with each other and orthogonal to the first electrode group, and A recording medium provided between the first electrode group and the second electrode group, the recording medium including a recording layer whose conductivity is locally changed by application of a voltage; 1
And one of the second electrode groups is selected, and the selected first electrode and second electrode group are selected.
Selection voltage applying means for applying the recording voltage between the first and second electrodes, and applying the recording voltage from the selected voltage applying means to between the selected first and second electrodes. A recording device for recording information by detecting a current flowing between the selected first electrode and the second electrode at least during application of the recording voltage and after application of the recording voltage. Current detection means for determining whether or not the information has been accurately recorded based on the value of the current detected by the current detection means, and when determining that the information has not been correctly recorded, the recording voltage The first
Determining means for sending a command to the selection voltage applying means to apply voltage again between the second electrode and the second electrode.

According to a second recording / reproducing apparatus of the present invention, a first electrode group provided in parallel with each other,
The second electrode group provided orthogonally to the first electrode group and the second electrode group provided between the first electrode group and the second electrode group, the conductivity is locally changed by applying a voltage. A recording medium including a recording layer, and a recording voltage and a reproduction voltage are respectively generated, and one of the first electrode group and one of the second electrode group are selected, respectively. Selection voltage applying means for applying the recording voltage and the reproduction voltage between the selected first electrode and the second electrode, respectively, wherein the selected first electrode and the second electrode And the recording voltage is applied from the selection voltage applying means to record information, and the reproducing voltage is applied from the selection voltage applying means to between the selected first and second electrodes. Recording / reproduction for reproducing the recorded information by applying a voltage Current detection means for detecting a current flowing between the selected first electrode and the second electrode at least one of at the time of applying the recording voltage and after the application of the recording voltage; It is determined whether or not the information has been accurately recorded based on the value of the current detected by the current detection means, and when it is determined that the information has not been accurately recorded, the recording voltage is compared with the first electrode. Determining means for sending a command to the selection voltage applying means to apply the voltage again to the second electrode.

According to a third recording apparatus of the present invention, a probe electrode, a recording medium provided opposite to the probe electrode and having a conductivity which is locally changed by application of a voltage, A voltage applying means for applying a recording voltage between the probe electrode and a probe electrode, wherein the recording apparatus applies the recording voltage between the recording medium and the probe electrode from the voltage applying means to record information. Current detection means for detecting a current flowing between the recording medium and the probe electrode at least at the time of application of the recording voltage and after application of the recording voltage, and the current detected by the current detection means It is determined whether or not the information has been accurately recorded by the value of the current, and when it is determined that the information has not been accurately recorded, the recording voltage is changed to the first electrode and the second electrode. Comprising a determining means for sending a command to said voltage applying means to apply again between.

A third recording / reproducing apparatus according to the present invention comprises: a probe electrode; and a probe electrode provided opposite to the probe electrode.
A recording medium whose conductivity is locally changed by application of a voltage, and voltage applying means for respectively applying a recording voltage and a reproducing voltage between the recording medium and the probe electrode; and Applying the recording voltage between the recording medium and the probe electrode to record information, and applying the reproduction voltage between the recording medium and the probe electrode from the voltage applying unit to apply the reproducing voltage. In a recording / reproducing apparatus for reproducing recorded information, current detecting means for detecting a current flowing between the recording medium and the probe electrode at least one of at the time of applying the recording voltage and after applying the recording voltage. And determining whether or not the information has been accurately recorded based on the value of the current detected by the current detecting means, and determining that the information has not been accurately recorded. Comprises a determination means for sending a command to said voltage applying means so as again applied between the said recording voltage said recording medium and said probe electrode.

[0025]

According to the first and second recording devices of the present invention, the first and second recording / reproducing devices are used when recording is performed by increasing the conductivity of a recording medium by applying a recording voltage. In addition, it can be determined whether or not the information has been correctly performed based on the presence or absence of a discharge current flowing between the first electrode and the second electrode after the application of the recording voltage or when the recording voltage is decreased. That is, in this case, information is recorded by accumulating charges on the recording medium while the recording voltage is being applied to the recording medium. Therefore, when the information is accurately recorded, the recording voltage is reduced. When a voltage is applied, a current due to charge accumulation flows instantaneously through the recording layer, and no discharge current is generated after the recording voltage is applied. On the other hand, when the recording of information is not performed accurately, the conductivity of the recording medium does not change due to the application of the recording voltage. A discharge current due to the discharge of the generated charge flows to the external circuit.

When recording is performed by applying a recording voltage to reduce the conductivity of the recording medium, the first electrode and the second electrode are applied after the recording voltage is applied or when the recording voltage is decreased. It can be determined whether or not the information has been correctly performed based on the presence or absence of a discharge current flowing between the two. That is, in this case, when information is recorded accurately, the conductivity decreases, and the discharge flowing to the external circuit immediately after the recording voltage is applied (when the recording voltage is applied) or when the recording voltage is decreased. An electric current is generated. On the other hand, when information is not accurately recorded, the conductivity of the recording medium does not change due to the application of the recording voltage. Therefore, when the recording voltage is applied, the discharge current is reduced by the first electrode. Does not flow between the first electrode and the second electrode.

Therefore, by detecting the presence or absence of the discharge current at least at the time of applying the recording voltage and after the application of the recording voltage, it is possible to determine whether or not the recording has been accurately performed.

The second recording apparatus and the second recording apparatus of the present invention
In the recording / reproducing apparatus, the first electrode group provided in parallel with each other, the second electrode group provided in parallel with each other and orthogonal to the first electrode group, and the second electrode group and the second electrode group provided in parallel with each other. A recording medium including a recording layer whose conductivity is locally changed by application of a voltage provided between the first electrode group and the second electrode group is provided between the first electrode group and the second electrode group. By selecting one of them and applying a recording voltage between the selected first and second electrodes to record information, the surface of the recording medium is divided into a grid pattern. The information can be recorded two-dimensionally.

In the third recording apparatus and the third recording / reproducing apparatus of the present invention, when recording is performed by applying a recording voltage to increase the conductivity of the recording medium, the recording is performed after the application of the recording voltage. Alternatively, it can be determined whether or not the information has been correctly performed based on the presence or absence of a discharge current flowing between the recording medium and the probe electrode when the recording voltage decreases. That is, in this case, the information is recorded by applying the recording voltage to the recording medium, and when the information is accurately recorded, no discharge current is generated after the application of the recording voltage. On the other hand, if the recording of information is not performed accurately, the conductivity of the recording medium does not change due to the application of the recording voltage, so that the accumulated charges are discharged after the application of the recording voltage. Discharge current flows between the recording medium and the probe electrode.

When recording is performed by applying a recording voltage to reduce the conductivity of the recording medium, the presence or absence of a discharge current flowing between the recording medium and the probe electrode when the recording voltage is applied is determined. , It can be determined whether the information has been correctly performed. That is, in this case, when information is accurately recorded, the discharge flowing between the recording medium and the probe electrode immediately after the recording voltage is applied (when the recording voltage is applied) or when the recording voltage is decreased. An electric current is generated. On the other hand, when the recording of the information is not performed accurately, the conductivity of the recording medium does not change due to the application of the recording voltage. Does not flow between electrodes.

Therefore, by detecting the presence or absence of the discharge current at least at the time of applying the recording voltage and after the application of the recording voltage, it is possible to determine whether or not the recording has been accurately performed.

The third recording apparatus and the third recording apparatus of the present invention
According to the recording / reproducing apparatus described above, information can be recorded (and reproduced) by applying the principle of the scanning tunneling microscope, so that a large amount of information can be recorded.

[0033]

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

FIG. 1 is a schematic diagram showing one embodiment of the first recording apparatus of the present invention.

The recording device 10 includes a recording medium 11 and a current
Amplifier 12, a determination circuit 13, and a recording pulse voltage generation circuit.
Road 14. Here, the recording medium 11 is the lower electrode 1
1₁And the upper electrode 11_Two And the lower electrode 11₁ And upper electrode
11_Two The conductivity is established by applying a voltage between
Changing recording layer 11_Three And That is, the recording medium 1
Numeral 1 has the element structure of the MIM element described above.
You. The recording pulse voltage generation circuit 14
And a generated recording pulse voltage is applied to the lower electrode 11.
₁ And upper electrode 11_Two And between the two. Current
The amplifier 12 is used when the recording voltage is applied and when the recording voltage is
Lower electrode 11 after application₁ And upper electrode 11 _Two Flow between
And amplifies the detected current. Judgment circuit 13
Is determined by the value of the current sent from the current amplifier 12.
Determine whether the information was recorded correctly and make sure that the information
If it is determined that no data was recorded,
Apply pressure to lower electrode 11₁ And upper electrode 11_Two Apply again between
Command to the recording pulse voltage generation circuit 14
It is.

The equivalent circuit of the recording medium 11 viewed from the recording pulse voltage generation circuit 14 is represented as a parallel circuit of an element resistance R and a capacitance C, as shown in FIG. The capacity C includes the capacity of a connection cable and the like.
Here, the resistance value of the element resistance R corresponds to the reciprocal of the conductivity ρ of the recording medium 11. Therefore, when the conductivity ρ of the recording medium 11 is small (ρ = ρ _L ), the capacitance C becomes dominant. Therefore, the equivalent circuit of the recording medium 11 has a capacitance C as shown in FIG. Only approximately. When the conductivity ρ of the recording medium 11 is large (ρ = ρ _H ),
Since the element resistance R becomes dominant, the equivalent circuit of the recording medium 11 is approximately represented only by the element resistance R as shown in FIG.

First, the recording medium 1 having a low conductivity ρ
A case where information is recorded by increasing the conductivity ρ of the recording medium 11 by applying a recording pulse voltage to 1 will be considered. As shown in FIG.
Over from ₁ to time t _2, the by applying a recording pulse voltage to the recording medium 11 is varied to a larger conductivity [rho _H conductivity [rho recording medium 11 from a small conductivity [rho _L.
At this time, the equivalent circuit of the recording medium 11 is approximately represented only by the capacitance C as shown in FIG. Therefore, as shown in FIG. 3B, the waveform of the current detected by the current amplifier 12 is such that the current for charging the capacitor C flows instantaneously at time t ₁ and then decreases exponentially. Becomes

Thereafter, the conductivity ρ of the recording medium 11 is changed at time t.
₂ changes from a small conductivity ρ _L to a large conductivity ρ _H , the electric charge stored in the capacitor C is
At the same time is discharged through the recording layer 11 _3, so that current flows. On the other hand, if the conductivity ρ of the recording medium 11 does not change and remains small ρ _L even when the recording pulse voltage is applied, the equivalent circuit of the recording medium 11 is as shown in FIG. It remains approximately represented only by the capacitance C as shown. Accordingly, the waveform of the time the current detected by the current amplifier 12, as shown in FIG. 3 (C), at time t ₂ which stops the application of the recording pulse voltage, the charge stored in the capacitor C is the upper electrode 11 ₃ and lower electrode 11 ₁
Then, the discharge current flows into the current amplifier 12 instantaneously, and then has an exponentially decreasing waveform. Therefore,
The presence or absence of this discharge current makes it possible to determine whether the conductivity ρ of the recording medium 11 has changed, that is, whether or not information has been recorded accurately.

Therefore, in the judgment circuit 13, FIG.
As shown in (B) and (C), the reference current value I ₀ is set in the direction in which the discharge current is generated, and the current exceeding the reference current value I ₀ is applied to the current amplifier 1 after application of the recording pulse voltage.
When the information is sent from the server 2, it is determined that the information has not been correctly recorded. In this case, the determination circuit 13 outputs to the recording pulse voltage generation circuit 14 a command to apply the recording pulse voltage to the recording medium 11 again. The reference current value I ₀ is may be set to a size capable of suppressing the occurrence of a malfunction.

Next, the recording medium 1 having a large conductivity ρ
A case where information is recorded by applying a recording pulse voltage to 1 to reduce the conductivity ρ of the recording medium 11 will be considered. When changing from the conductivity [rho is larger conductivity of the recording pulse voltage is applied to the recording medium 11 [rho _H to a small conductivity [rho _L, since the relative magnitude of the capacitance C in the equivalent circuit of the recording medium 11 is increased, The effect of the capacitance C becomes significant. Therefore, immediately after the recording pulse voltage is applied (when the recording pulse voltage is applied), the current amplifier 1
In 2, the discharge current of the charge stored in the capacitor C is detected. In contrast, when the recording pulse voltage is applied and the conductivity ρ of the recording medium 11 does not change, the capacitance C
Does not appear, and the discharge current is not detected by the current amplifier 12 when the recording pulse voltage is applied. Therefore,
In the determination circuit 13, the reference current value I ₀ is set in the direction in which the discharge current is generated. When a current exceeding the reference current value I ₀ is not sent from the current amplifier 12 at the time of applying the recording pulse voltage, the information By determining that the recording has not been performed accurately, it can be determined whether or not the information has been correctly recorded. If the determination circuit 13 determines that the information has not been correctly recorded,
The determination circuit 13 outputs to the recording pulse voltage generation circuit 14 a command to apply the recording pulse voltage to the recording medium 11 again.

As described above, in the recording apparatus 10 of the present embodiment, the application of the recording pulse voltage to the recording medium 11 can be automatically repeated until the information is recorded accurately. The error rate during recording can be greatly reduced.

Next, an embodiment of the first recording / reproducing apparatus of the present invention will be described.

[0043] While the recording apparatus 10 shown in FIG. 1 comprises only the recording function, reproducing voltage (bias voltage for reproduction) between the lower electrode 11 ₁ and the upper electrode 11 ₂ of the recording medium 11 at the time of reproduction A recording / reproducing apparatus having a reproducing function can also be configured by adding to the recording apparatus 10 a means for applying the information and a data reproducing means for reproducing information from the current sent from the current amplifier 12.

Next, an embodiment of the second recording apparatus of the present invention will be described with reference to FIGS. 4 (A) and 4 (B).

The recording device 50 includes a recording medium 51, a recording pulse voltage generation circuit 52, a lower electrode selection circuit 53,
An upper electrode selection circuit 54, a current amplifier 55, a determination circuit 56, and a microcomputer 57 are included. The components of the recording device 50 will be described below.

(1) Recording Medium 51 The recording medium 51 has a lower electrode group provided in parallel with each other.
(Lower electrode 51₁₁~ 51 ₁₈) And parallel to each other and below
An upper electrode group (upper electrode) provided orthogonal to the electrode group
Pole 51_{twenty one}~ 51₂₈) And between the lower electrode group and the upper electrode group
Conductivity changes locally by applying voltage
Layer 51 made of LB film_Three And

(2) Recording pulse voltage generating circuit 52, lower electrode selecting circuit 53 and upper electrode selecting circuit 54 The recording pulse voltage generating circuit 52 generates a recording pulse voltage in accordance with a command sent from the microcomputer 57. At the same time, a recording pulse voltage is generated in accordance with a command sent from the determination circuit 56. The lower electrode selection circuit 53 includes a lower electrode group (lower electrodes 51 ₁₁ to
51 ₁₈ ) is selected and connected to the recording pulse voltage generation circuit 52. Upper electrode selection circuit 5
4 is intended to be connected to a current amplifier 55 to select one of the upper electrodes (upper electrode 51 _{21-51 28).}

(3) Current Amplifier 55 The current amplifier 55 is selected by the lower electrode and the upper electrode selection circuit 54 selected by the lower electrode selection circuit 53 at the time of application of the recording pulse voltage and after the application of the recording pulse voltage. It detects and amplifies the current flowing between the upper electrode and the upper electrode.

(4) Judgment Circuit 56 The judgment circuit 56 judges whether or not the information has been accurately recorded based on the value of the current sent from the current amplifier 55.
When it is determined that the information has not been accurately recorded, a command is sent to the recording pulse voltage generation circuit 52 to generate the recording pulse voltage again.

(5) Microcomputer 57 The microcomputer 57 controls the recording pulse voltage generating circuit 52, the lower electrode selecting circuit 53, and the upper electrode selecting circuit 54, respectively.

Next, the operation of the recording device 50 will be described.

A command to generate a recording pulse voltage is sent from the microcomputer 57 to the recording pulse voltage generation circuit 5.
2, the recording pulse voltage is generated by the recording pulse voltage generation circuit 52. A command to select a lower electrode to which a recording pulse voltage is to be applied (for example, a lower electrode 51 _{11 at the} left end in the drawing in FIG. 10A) is output from the microcomputer 57 to the lower electrode selection circuit 53 and information is recorded. (For example, upper electrode 51 _{21 at} the upper end shown in FIG. 10A)
Is output from the microcomputer 57 to the upper electrode selection circuit 54. Thus, between the upper electrode 51 ₂₁ selected by the lower electrode 51 ₁₁ selected by the lower electrode selection circuit 53 upper electrode selection circuit 54, is recorded pulse voltage is applied, on the recording layer 51 ₃ Recording of information is performed.

The current flowing between the lower electrode selection circuit 53 upper electrode 51 ₂₁ selected by the lower electrode 51 ₁₁ selected upper electrode selection circuit 54 by the current amplifier 55
, And is sent to the determination circuit 56. The determination circuit 56 uses the current sent from the current amplifier 55 to determine the determination circuit 1 shown in FIG.
By the same method as in 3, it is determined whether or not the information has been correctly recorded. When it is determined that the recording has been correctly performed, information that the information has been correctly recorded is sent from the determination circuit 56 to the microcomputer 57. When the microcomputer 57 receives this information from the determination circuit 56, it selects the next recording position.
A command to select the lower electrode to which the recording pulse voltage is to be applied (for example, the second lower electrode 51 ₁₂ from the left end in the figure (A)) is output from the microcomputer 57 to the lower electrode selection circuit 53. A command to select an upper electrode (for example, the upper electrode 51 _{21 at} the upper end in the figure shown in FIG. 10A) corresponding to the position where information is recorded is output from the microcomputer 57 to the upper electrode selection circuit 54. On the other hand, when it is determined that the recording has not been correctly performed, information indicating that the information is to be recorded again is output from the determination circuit 56 to the microcomputer 57. When this information is sent from the determination circuit 56, the microcomputer stops the operation of selecting the next recording position. Further, a command to regenerate the recording pulse voltage is output from the determination circuit 56 to the recording pulse voltage generation circuit 52. Thus, information is recorded again in the same position of the recording layer 51 _3. Information is two-dimensionally recorded on the recording medium 51 by repeating such an operation.

Therefore, in the recording device 50, the application of the recording pulse voltage is repeated until the information is accurately recorded, so that the error rate at the time of forming the recording bit can be greatly reduced. As for the erasing operation in the recording device 50, the information recorded on the recording medium 51 can be stably erased by performing the same operation as the above-described operation at the time of recording.

Next, an embodiment of the second recording / reproducing apparatus of the present invention will be described.

Although the recording apparatus 50 shown in FIG. 4 has only a recording function, the recording pulse voltage generation circuit 52
By adding the following functions to the microcomputer 57, a recording / reproducing apparatus having a reproducing function can be configured. (1) A function of generating a reproducing voltage at the time of reproducing is added to the recording pulse voltage generating circuit 52. (2) The microcomputer 57 outputs a command to select a lower electrode to which a reproduction voltage is to be applied to the lower electrode selection circuit 53 at the time of reproduction, and causes the microcomputer 57 to select an upper electrode corresponding to a position where information is reproduced. A function to output a command to the upper electrode selection circuit 54, and a current amplifier 1 during reproduction.
2 and a function of reproducing information from the current sent from the device 2.

The recording pulse voltage generation circuit 52 shown in the above (1) is provided with a means for generating a reproduction voltage at the time of reproduction instead of adding a function of generating a reproduction voltage at the time of reproduction. Is also good.

Next, an embodiment of the third recording / reproducing apparatus of the present invention will be described with reference to FIG.

The recording / reproducing apparatus 100 determines whether or not the information has been accurately recorded based on the value of the current detected by the current amplifier 119. If it is determined that the information has not been correctly recorded, the recording / reproducing apparatus 100 records the recording voltage. Medium 101 and probe electrode 11
4 is different from the conventional recording / reproducing apparatus 600 shown in FIG. 6 in that a determination circuit 130 for sending a command to the power supply 123 so as to apply the voltage again to the power supply 123 is provided.

Next, the operation of the recording / reproducing apparatus 100 during recording and reproduction will be described.

At the time of recording, the power supply 123 is controlled by the microcomputer 120 so that the power supply 123
A predetermined bias voltage is applied to one substrate electrode 103.
Thus, the probe electrode 114 and the recording layer of the recording medium 101
A predetermined bias voltage is applied between the bias voltage and the bias voltage. At this time, the current detected by the probe electrode 114 (that is, the current flowing between the probe electrode 114 and the recording layer 104) is
After being amplified by the current amplifier 119, the microcomputer 120, the first servo circuit 121 and the second servo circuit
122.

In the first servo circuit 121, the current amplifier 11
9 The value of the current sent from
0 is compared with the first current set value sent from the first current setting, and a coarse movement control signal for coarsely controlling the distance between the probe electrode 114 and the recording layer 104 is set so that the two values become the same.
It is output to the direction coarse movement control circuit 113. The Z-direction coarse movement control circuit 113 generates a coarse movement mechanism 111 based on the coarse movement control signal.
Is generated in the Z-axis direction shown in FIG.
Output to 111. Thereby, the distance between the probe electrode 114 and the recording layer 104 is roughly adjusted. In the second servo circuit 122, the value of the current sent from the current amplifier 119 is compared with the second set current value sent from the microcomputer 120, so that the two values become the same. A fine movement control signal for finely controlling the distance between the probe electrode 114 and the recording layer 104 is supplied to the Z-direction fine movement control circuit 118.
Is output to The Z-direction fine movement control circuit 118 generates a signal for driving the Z-direction fine movement mechanism 115 in the illustrated Z-axis direction based on the fine movement control signal, and outputs the signal to the Z-direction fine movement mechanism 115. Thereby, the probe electrode 114 and the recording layer 104
Is finely adjusted to maintain a predetermined distance.

The XY direction coarse movement control circuit 112 generates a signal for driving the coarse movement mechanism 111 in the illustrated X-axis direction and the Y-axis direction based on a command from the microcomputer 120, and outputs the signal to the coarse movement mechanism 111. You. Further, the XY direction fine movement control circuit 117 generates a signal for driving the XY direction fine movement mechanism 115 in the illustrated X-axis direction and the Y-axis direction based on a command from the microcomputer 120, and outputs the signal to the XY direction fine movement mechanism 115. You. As a result, the probe electrode 114 is scanned to the recording position of the recording medium 101.

In the power supply 123, the microcomputer 120
, A recording bias voltage and a recording pulse voltage are generated. A recording bias voltage and a recording pulse voltage are applied to the recording layer 104 via the substrate electrode 102 of the recording medium 101. A recording bit is formed on the recording layer 104 by locally changing the conductivity of the recording layer 104 where the recording pulse voltage is applied.

Here, in the initial state, the small conductivity ρ
By applying a recording voltage (recording bias voltage and recording pulse voltage) to the recording layer 104 having _L ,
In the case where recording is performed by increasing the conductivity of the recording layer 104, the conductivity ρ of the recording layer 104 is reduced by applying the recording voltage, as described in the operation of the recording apparatus 10 shown in FIG. when changes in conductivity of greater [rho _H from _L is that the discharge current is not detected by the current amplifier 119 after application of the recording voltage, it is applied despite changes the conductivity of the recording layer 104 [rho is the recording voltage If not,
After the application of the recording voltage, the discharge current is detected by the current amplifier 119. Therefore, by determining whether or not the discharge current is sent from the current amplifier 119 after the application of the recording voltage, the determination circuit 130 can determine whether or not the information has been recorded accurately. The judgment circuit 13
The method for detecting the presence or absence of the discharge current at 0 may be the same as the method for detecting the presence or absence of the discharge current in the determination circuit 13 shown in FIG.

In the determination circuit 130, if no discharge current is detected in the current sent from the current amplifier 119 after the application of the recording voltage, it is determined that the information has been recorded accurately, and The information that the recording has been correctly performed is sent from the determination circuit 130 to the microcomputer 120. In the microcomputer 120, when this information is sent from the determination circuit 130, the scanning operation of the probe electrode 114 to the next recording position is started. On the other hand, the judgment circuit 13
In the case of 0, if a discharge current is detected in the current sent from the current amplifier 119 after the application of the recording voltage, it is determined that the information recording was not correctly performed, and the recording voltage is applied again. Information to be transmitted is sent from the determination circuit 130 to the microcomputer 120. In the microcomputer 120, when this information is sent from the determination circuit 130, the scanning operation of the probe electrode 114 to the next recording position is stopped. Also, a command to reapply the recording voltage (recording bias voltage and recording pulse voltage) is issued by the power supply 123.
The recording voltage is sent from the power supply 123 to the recording medium 101.
Is applied again. Thereby, since the application of the recording voltage is repeated until the information is recorded accurately, the error rate at the time of forming the recording bit can be greatly reduced,
Information can be reliably recorded on the recording medium 101.

In the initial state, the large conductivity ρ _H
A recording voltage (recording bias voltage and recording pulse voltage) is applied to the recording layer 104 having
When conducting recording by the conductivity small, as described in the operation of the recording apparatus 10 shown in FIG. 1, the conductivity The conductivity of the recording layer 104 [rho is larger by application of the recording voltage [rho _H When the conductivity changes from か ら to a small conductivity ρ _L , the discharge current is detected by the current amplifier 119 immediately after the application of the recording voltage (when the recording voltage is applied). When the conductivity ρ of the recording layer 104 does not change, the discharge current is not detected by the current amplifier 119 when the recording voltage is applied. Therefore, also in this case, by determining whether or not the current sent from the current amplifier 119 includes a discharge current, the determination circuit 130 can determine whether or not the information has been recorded accurately. it can. The method of detecting the presence or absence of a discharge current in the determination circuit 130 may be the same as the method of detecting the presence or absence of a discharge current in the determination circuit 13 shown in FIG.

When the discharge current is detected in the current sent from the current amplifier 119 when the recording voltage is applied, the determination circuit 130 determines that the information has been correctly recorded, and determines that the information has been recorded. The information that the calculation has been correctly performed is sent from the determination circuit 130 to the microcomputer 120. In the microcomputer 120, when this information is sent from the judgment circuit 130, the probe electrode 11 moves to the next recording position.
The scanning operation of 4 is started. On the other hand, in the determination circuit 130,
When a discharge current is not detected in the current sent from the current amplifier 119 at the time of applying the recording voltage or after the application of the recording voltage, it is determined that the information has not been accurately recorded, and The information that the voltage is applied again,
The signal is sent from the judgment circuit 130 to the microcomputer 120. In the microcomputer 120, when this information is sent from the determination circuit 130, the scanning operation of the probe electrode 114 to the next recording position is stopped. Further, a command to apply the recording voltage (recording bias voltage and recording pulse voltage) again is sent to the power supply 123, and the recording voltage is applied again from the power supply 123 to the recording medium 101. As a result, the application of the recording voltage is repeated until the information is accurately recorded, so that the error rate at the time of forming the recording bit can be greatly reduced, and the information can be reliably recorded on the recording medium 101. .

As for the erasing operation in the recording / reproducing apparatus 100, the information recorded on the recording medium 101 can be stably erased by performing the same operation as the above-described operation at the time of recording.

At the time of reproduction, the probe electrode 114 is scanned to the reproduction position of the recording medium 101 in the same manner as at the time of recording. Thereafter, the power supply 123 generates a reproducing bias voltage. The reproduction bias voltage is applied to the substrate electrode of the recording medium 101.
It is applied to the recording layer 104 via 102. At this time, the current flowing between the recording layer 104 and the probe electrode 114 is amplified by the current amplifier 119 and then sent to the microcomputer 120. The microcomputer 120 determines the conductivity of the recording layer 104 from the value of the sent current. Since the presence or absence of a recording bit can be determined from the obtained value of the conductivity, the recorded information can be reproduced.

Next, an embodiment of the third recording apparatus of the present invention will be described.

Since the recording / reproducing apparatus 100 shown in FIG. 5 has a recording function and a reproducing function, the power supply 123 has a function of generating a reproducing bias voltage, and the microcomputer 120 has a Although the function of reproducing information from the supplied current was provided, the second recording apparatus having only the recording function according to the present invention was constituted by omitting these functions of the power supply 123 and the microcomputer 120. Can be.

[0073]

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

It is possible to determine whether or not the information has been correctly recorded by merely detecting the presence or absence of the discharge current generated at least at the time of the application of the recording voltage and after the application of the recording voltage. When it is determined that the recording has not been accurately performed, the recording operation can be performed again, so that the information can be reliably recorded on the recording medium whose conductivity changes by applying a voltage.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a first recording apparatus of the present invention.

FIG. 2 is a diagram showing an equivalent circuit of the recording medium shown in FIG. 1, wherein (A) is a diagram showing a general equivalent circuit of the recording medium;
(B) is a diagram showing an approximate equivalent circuit when the conductivity of the recording medium is small, and (C) is a diagram showing an approximate equivalent circuit when the conductivity of the recording medium is large.

3A is a graph showing an example of a waveform of a current detected by the current amplifier shown in FIG. 1; FIG. 3A is a graph showing a waveform of a recording pulse voltage; FIG. FIG. 4C is a graph showing an example of a current waveform detected by the current amplifier when the current decreases, and FIG. 4C is a graph showing an example of a current waveform detected by the current amplifier when the conductivity of the recording medium does not change. is there.

FIG. 4 is a schematic configuration diagram illustrating an embodiment of a second recording apparatus according to the present invention, in which (A) is a schematic configuration diagram of the recording apparatus, and (B) is a schematic diagram.
Is a side view of the recording medium.

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

FIG. 6 is a schematic configuration diagram showing a conventional example of a recording / reproducing apparatus according to the present invention.

[Explanation of symbols]

10,50 recording apparatus 11, 51 recording medium 11 _1, 51 ₁₁ to 51 ₁₈ lower electrode 11 _2, 51 _{21-51 28} upper electrode 11 _3, 51 ₃ recording layer 12,55 current amplifier 13,56 judging circuit 14 and 52 Recording pulse voltage generation circuit 53 Lower electrode selection circuit 54 Upper electrode selection circuit 57 Microcomputer 100 Recording / reproducing device 101 Recording medium 102 Substrate 103 Substrate electrode 104 Recording layer 110 Recording medium stage 111 Coarse motion mechanism 112 XY coarse motion control circuit 113 Z direction coarse movement control circuit 114 Probe electrode 115 XY direction fine movement mechanism 116 Z direction fine movement mechanism 117 XY direction fine movement control circuit 118 Z direction fine movement control circuit 119 Current amplifier 120 Microcomputer 121 First servo circuit 122 Second servo circuit 123 Power supply 130 Judgment circuit R element resistance C capacity I ₀ Reference current value t ₁ , t ₂ Time X, Y, Z axis

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H01L 49/02 H01L 49/02 (72) Inventor Etsuro Kishi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. ( 56) References JP-A-4-90150 (JP, A) JP-A-5-342773 (JP, A) JP-A-6-215425 (JP, A) JP-A-7-7197 (JP, A) ) Surveyed field (Int.Cl. ⁷ , DB name) G11B 9/14 G11B 20/18 G11C 29/00 H01L 49/02

Claims (6)

(57) [Claims] 1. A recording medium comprising: a first electrode, a second electrode, and a recording layer provided between the first electrode and the second electrode, the recording layer having a conductivity that changes when a voltage is applied. And a voltage applying means for applying a recording voltage between the first electrode and the second electrode, wherein the voltage applying means
A recording device that applies the recording voltage between the first electrode and the second electrode to record information, wherein the first voltage is applied at least one of at the time of applying the recording voltage and after the application of the recording voltage. Current detection means for detecting a current flowing between the first electrode and the second electrode; and determining whether or not the information has been accurately recorded by the value of the current detected by the current detection means, And determining means for sending a command to the voltage applying means to apply the recording voltage again between the first electrode and the second electrode when it is determined that the information has not been accurately recorded. A recording device, characterized in that: 2. A recording medium including a first electrode, a second electrode, and a recording layer provided between the first electrode and the second electrode, the recording layer having a conductivity that changes when a voltage is applied. Voltage applying means for applying a recording voltage and a reproducing voltage between the first electrode and the second electrode, respectively, and the first electrode and the second electrode The recording voltage is applied between the first electrode and the second electrode to record information by applying the recording voltage between the first electrode and the second electrode. In a recording / reproducing apparatus for reproducing information, a current detection for detecting a current flowing between the first electrode and the second electrode at least one of at the time of applying the recording voltage and after applying the recording voltage. Means, and a value of the current detected by the current detecting means. To determine whether or not the information has been accurately recorded. If it is determined that the information has not been accurately recorded, the recording voltage is applied again between the first electrode and the second electrode. And a determination means for sending a command to the voltage application means. 3. A first electrode group provided in parallel with each other,
A second electrode group provided in parallel with each other and orthogonal to the first electrode group, and a conductive member provided between the first electrode group and the second electrode group, which is electrically conductive by applying a voltage. A recording medium including a recording layer whose rate changes locally, a recording voltage is generated, and one of the first electrode group and one of the second electrode group are selected. And a selection voltage applying means for applying the recording voltage between the selected first electrode and the second electrode, wherein a selection voltage applying unit is provided between the selected first electrode and the second electrode. In a recording apparatus that records information by applying the recording voltage from the selection voltage applying unit, the selected first electrode and / or at least one of at the time of applying the recording voltage and after applying the recording voltage. Current detection means for detecting a current flowing between the first electrode and the second electrode; It is determined whether or not the information has been accurately recorded based on the value of the current detected by the current detection means, and when it is determined that the information has not been accurately recorded, the recording voltage is set to the first electrode. A recording device comprising: a determination unit that sends a command to the selection voltage application unit to apply the voltage again to the second electrode. 4. A first electrode group provided in parallel with each other,
A second electrode group provided in parallel with each other and orthogonal to the first electrode group, and a conductive member provided between the first electrode group and the second electrode group, which is electrically conductive by applying a voltage. A recording medium including a recording layer whose rate changes locally; a recording voltage and a reproduction voltage;
And one of the second electrode groups is selected, and the selected first electrode and second electrode group are selected.
And a selection voltage application unit for applying the recording voltage and the reproduction voltage between the first and second electrodes, respectively. The recording information is recorded by applying the recording voltage, and the reproduction voltage is applied from the selected voltage applying means between the selected first electrode and the second electrode to thereby record the recorded information. A current for detecting a current flowing between the selected first electrode and the second electrode at least one of at the time of applying the recording voltage and after the application of the recording voltage. Detecting means for judging whether or not the information has been accurately recorded based on the value of the current detected by the current detecting means, and when judging that the information has not been accurately recorded, the recording voltage is set to the First Recording and reproducing apparatus characterized by comprising a determining means for sending a command to the selected voltage application means to re-applied between the To pole second electrode. 5. A probe electrode, a recording medium provided opposite to the probe electrode, the conductivity of which locally changes by applying a voltage, and a recording medium between the recording medium and the probe electrode. A recording device for recording information by applying the recording voltage between the recording medium and the probe electrode from the voltage application unit, the device comprising: And current detection means for detecting a current flowing between the recording medium and the probe electrode at least on one side after the application of the recording voltage, and the information is accurately determined by the value of the current detected by the current detection means. It is determined whether or not the information has been recorded correctly, and if it is determined that the information has not been accurately recorded, the recording voltage is applied again between the first electrode and the second electrode. Recording apparatus characterized by comprising a determining means for sending a command to the voltage application means. 6. A probe electrode, a recording medium provided opposite to the probe electrode, the conductivity of which is locally changed by application of a voltage, and a recording medium between the recording medium and the probe electrode. Voltage applying means for applying a voltage and a reproducing voltage, respectively, wherein the voltage applying means applies the recording voltage between the recording medium and the probe electrode to record information, and the voltage applying means A recording / reproducing apparatus for reproducing the recorded information by applying the reproducing voltage between the recording medium and the probe electrode, wherein at least when the recording voltage is applied and after the recording voltage is applied. On the other hand, current detection means for detecting a current flowing between the recording medium and the probe electrode, and the information is accurately recorded by the value of the current detected by the current detection means. It is determined whether or not the information has not been accurately recorded, and when it is determined that the information has not been accurately recorded, a determination is made to send a command to the voltage applying means to apply the recording voltage again between the recording medium and the probe electrode. Recording / reproducing apparatus characterized by comprising: