JP3206964B2 - Reading device of electrochemical memory element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an electrochemical reaction,
The present invention relates to a reading device for an electrochemical memory element that stores a voltage or integrates an electric quantity and stores the electric quantity.

[0002]

2. Description of the Related Art An electrochemical memory element is an element that stores a voltage or integrates a quantity of electricity flowing through a circuit with time, stores the value, and outputs the value as a voltage of the element. It is also called a storage element, an analog memory, or an electric quantity integrator.

Among the above-mentioned elements, those using an electrochemical phenomenon include a silver ion-electron mixed conductor represented by Ag ₂ Se—Ag ₃ PO ₄ as a working electrode material,
bAg ₄ I ₅ (Journal of Applied Electrochemistry, v
ol. 3, p. 129, (1973)) or a silver ion conductive solid electrolyte represented by Ag ₆ I ₄ WO ₄ (electrochemistry, vol. 44, No. 8, p. 535, (1976)). An element used for a solid electrolyte layer has been proposed. In addition, a silver ion conductive solid electrolyte is used as a solid electrolyte, and Ag _x V ₂ O _5-y (0.35 <x, y
Has been proposed using a composite oxide of silver and vanadium oxide represented by oxygen deficiency.

[0004] These devices use the fact that the chemical potential of silver ions in a silver ion-electron mixed conductor changes depending on the silver content in the mixed conductor. More specifically, the amount of electricity is detected and stored according to the principle described below.

The current flowing through the device flows as silver ions in the solid electrolyte. The silver content in the mixed conductor changes due to the flowing silver ions. As a result, the chemical potential of silver in the mixed conductor changes, and the change is detected and stored as a voltage.

[0006] As described above, such an electrochemical memory element is used as an electric quantity integrator for integrating a flowing electric quantity and outputting it as a voltage, or as a potential storage element (analog memory) for storing a voltage. However, in either case, it is desirable that the response speed is high.

In such an element, a substantially proportional relationship is established between the integral value of the amount of energized electricity, that is, the amount of charged electricity, and the terminal voltage of the element as in a general capacitor. Assuming that the proportionality constant is C, the unit is coulomb / V, that is, F (Faraday), and the relational expression is expressed as (Equation 1).

[0008]

(Equation 1)

Here, in order to consider the response speed, a series circuit of the internal resistance of the element and the capacitance of the element is considered as an equivalent circuit of the electrochemical memory element. The capacitance of the element is C
(F), the internal resistance of the element is R (Ω), and the voltage is
Assuming that the voltage of the electrochemical memory element when V0volt is applied is V, between the amount of charge Q and the current I flowing through the circuit,
The relational expression of (Equation 2) holds.

[0010]

(Equation 2)

The Kirchhoff's theorem in this equivalent circuit is expressed by (Equation 3).

[0012]

(Equation 3)

From the equations (2) and (3), if the element is charged with V0 by an external circuit from the state where the terminal voltage of the element is 0, if R and C do not change with time, t seconds after the start of charging The terminal voltage V of the element is expressed by (Equation 4).

[0014]

(Equation 4)

(Equation 4) shows that in order to increase the response speed of the element, it is desirable to reduce RC, that is, to reduce the internal resistance and reduce the capacitance.

Also, when integrating such elements, it is important to increase the recording density. At that time, however, one element is also miniaturized, and its capacity is small. Become.

[0017]

However, the electrochemical memory element has a problem that when the capacity of the element is reduced, the storage performance of the storage voltage of the element or the integrated value of the electric quantity is reduced for the following reasons. are doing.

An electrochemical memory element outputs an integrated amount of electricity as a voltage of the element. When the voltage of the element is read by a voltmeter or the like, the voltmeter acts as an external load and a current flows from the element. As a result, the integrated electric quantity is discharged (discharged) to the outside. In particular, when the capacitance of the element is made small, the ratio of the amount of electricity consumed by the discharge to the stored amount of electricity becomes large, and the effect becomes large. Therefore, when improving the recording speed or the recording density, it is necessary to take into account the power consumption in the external circuit due to reading of the recorded contents, and there is a problem that the miniaturization is limited. Have.

Although an electrochemical memory element originally has a property that can be used as an analog memory,
When the storage voltage changes as described above, there is a problem that the analogity of the memory cannot be expected to be accurate, and the memory can be used only as a digital memory.

The present invention solves the above-mentioned problems of the prior art,
An object of the present invention is to provide an apparatus for reading stored contents of an electrochemical memory element without loss of stored contents of the electrochemical memory element due to discharge to an external load.

[0021]

Means for Solving the Problems] To achieve the above object, readout device electrochemical memory device of the present invention, the solid
A device for reading an electrochemical memory element comprising at least a body electrolyte and at least a pair of electrodes arranged with the solid electrolyte interposed therebetween, wherein information of the electrochemical memory element is read by a machine of the electrochemical memory element. A means for reading out by means of a target displacement.

In the above configuration, the means for reading by the mechanical displacement of the electrochemical memory element is any one selected from optical system reading means, atomic force measurement reading means, and tunnel current measurement reading means. Preferably, there is.

In the above structure, it is preferable that at least one pair of electrodes contains a substance which shows a reversible volume change with an electrochemical oxidation-reduction reaction. Further, in the above structure, it is preferable that the substance exhibiting a reversible volume change accompanying the electrochemical oxidation-reduction reaction is a substance which electrochemically moves ions into and out of ion sites in the lattice.

Further, in the above structure, the solid electrolyte is
It is preferably a silver halide-silver oxyacid-based silver ion conductive solid electrolyte.

In the above structure, it is preferable that the substance capable of moving ions into and out of the lattice is a composite oxide composed of a transition metal oxide containing at least silver and vanadium oxide.

Further, in the above configuration, the pair of electrodes are
It is preferable that they are arranged to face each other with the electrolyte layer interposed therebetween. Further, in the above configuration, the electrochemical memory element includes:
Preferably, a fixed pointer or fixed optical device is provided.

[0027]

According to the configuration of the present invention described above, the information is read out by the mechanical displacement of the electrochemical memory element, and the information of the electrochemical memory element can be stored without any electrical connection to the external circuit. Can be read. As a result, no discharge to the external circuit is performed, and even when an element having a small capacity is used, the stored contents are not lost due to the discharge, and excellent characteristics are maintained in storing the stored contents.

Further, as a mechanical displacement reading device, it is preferable to use an optical system because it can accurately measure the electrochemical memory element in a non-contact manner. As an example, a case where the deflection is read out as the mechanical displacement of the electrochemical memory element will be described.

FIG. 1 shows a principle diagram. In this example, a reflection plate 2 is used as an optical device fixed to the electrochemical memory element 1. Here, the length of the electrochemical memory element is l, and the displacement due to the bending is d. A relational expression of (Equation 5) is established between the radius of curvature r of the electrochemical memory element and the central angle θ, and a relational expression of (Equation 6) is provided between the displacement d due to the bending. Holds.

[0030]

(Equation 5)

[0031]

(Equation 6)

Here, when light is irradiated from a point A which is a distance L away from the electrochemical memory element, the irradiated light
To reach point B. Here, from point A to point
Assuming that the distance to B is x, a relational expression expressed by (Equation 7) is established between x and L.

[0033]

(Equation 7)

Here, when the deflection of the electrochemical memory element is small, (Equation 6) and (Equation 7) are expanded to the second order terms to obtain (Equation 8) and (Equation 9), respectively. ), X, l, L, d is given by (Equation 10)
Can be obtained.

[0035]

(Equation 8)

[0036]

(Equation 9)

[0037]

(Equation 10)

As an example, the length of the electrochemical memory element is
Assuming that l = 10 mm, the magnitude of the deflection is d = 0.1 mm, and the distance to the light irradiation point is L = 100 mm, the distance between points A and B is x = 28 mm, and the magnitude of the deflection is approximately 300 times. Amplification can be detected. Therefore, by placing a line sensor or the like at a location corresponding to points A and B, the mechanical displacement of the electrochemical memory element can be accurately read out in a non-contact manner.

In the case where the electrochemical memory element is made thinner in order to integrate it, the mechanical displacement becomes very small. In such a case, it is necessary to detect a small displacement, and such a small mechanical displacement can be precisely measured without contacting the electrochemical memory element by measuring an atomic force. Preferably, the displacement is detected by measuring the atomic force.

Since such a minute mechanical displacement can be accurately measured without contacting the electrochemical memory element by measuring the tunnel current, it is preferable to detect the displacement by measuring the tunnel current.

Further, in the pair of electrodes of the electrochemical memory element, as at least one of the pair of electrodes, an electrode containing a substance which exhibits a reversible volume change accompanying an electrochemical oxidation-reduction reaction is used. This is preferably used because mechanical displacement of the element accompanying the electrochemical reaction can be generated.

Further, as a substance which exhibits a reversible volume change accompanying the electrochemical oxidation-reduction reaction, a substance which can electrochemically move ions into and out of ion sites in the lattice is used. The reaction is particularly preferable since the reaction becomes rich in reversibility and writing and erasing of the electrochemical memory element can be repeatedly and smoothly performed.

Further, in the case of reading out the stored contents by detecting the mechanical displacement of the electrodes, the electrochemical memory element is an all-solid-state device that does not need to house the electrochemical system in a battery container such as a metal container. It is desirable to use a solid electrolyte which can convert the electrochemical system into an all solid system. Further, by making the element all solid using a solid electrolyte, the element can be thinned or finely processed, and the element can be miniaturized. As a result, when the elements are integrated, the solid electrolyte is preferably used because the degree of integration can be increased.

Further, as a solid electrolyte, a silver halide-silver oxyacid based silver ion conductive solid electrolyte is chemically stable even in the air, so that the reliability of the electrochemical memory element is improved. It is particularly preferably used because it is not necessary to put the element in a sealed container and the mechanical displacement of the element can be easily read. Furthermore, a silver ion conductive solid electrolyte is particularly preferably used because it has a relatively high ionic conductivity among solid electrolytes and can increase the writing speed of an electrochemical memory element.

As an electrode active material to be combined with a silver ion conductive solid electrolyte, when combined with a silver ion conductive solid electrolyte, it exhibits high electrode activity, can move ions into and out of the lattice, and has an excellent reaction. A composite oxide composed of a transition metal oxide containing at least silver and vanadium oxide is preferably used because of its high reversibility.

Further, when both of the pair of electrodes contain a composite oxide composed of a transition metal oxide containing at least silver and vanadium oxide, the reversibility of writing / erasing of the electrochemical memory element is improved. Is particularly preferably used because it is particularly excellent.

Further, the pair of electrodes are preferably arranged to face each other with the electrolyte layer interposed therebetween, since the ion conduction path is shortened. Further, when the electrodes are arranged to face each other as described above, it is preferable that the mechanical displacement can be observed as a large one by measuring the bending of the electrochemical memory element as a so-called bimorph type.

By fixing the pointer to the electrochemical memory element, the mechanical displacement of the electrochemical memory element can be read out as a large displacement, so that it is preferably used as a configuration of an electrochemical memory device.

Further, by fixing the optical device to the electrochemical memory element, it is possible to read out the mechanical displacement of the electrochemical memory element with high sensitivity in a non-contact manner. .

[0050]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. Example 1 A silver ion conductive solid electrolyte represented by 4AgI.Ag ₂ WO ₄ was used as an electrolyte, and a pair of electrodes arranged via this solid electrolyte layer were both reversibly associated with an electrochemical oxidation-reduction reaction. As a substance showing a typical volume change, a composite oxide composed of silver and vanadium oxide represented by Ag _0.7 V ₂ O ₅ , which is a substance capable of electrochemically transferring ions into and out of ion sites in a lattice, is used. An electrochemical memory device was constructed by the following method. A laser displacement meter was used as an optical system used for reading.

First, a solid electrolyte and a composite oxide to be used were synthesized by the following method. First, AgI, Ag ₂
O, WO ₃ are weighed so as to have a molar ratio of 4: 1: 1,
Mix in an alumina mortar. After pressure-molding this mixture into pellets, it was sealed under reduced pressure in a Pyrex tube,
Melted at 17 ° C. for 17 hours. The reaction product was ground to 200 mesh or less in a mortar to obtain a silver ion conductive solid electrolyte represented by 4AgI · Ag ₂ WO _4.

Next, a composite comprising silver and vanadium oxide
The oxide was synthesized by the following method. Represented by V2O5
Vanadium oxide and metallic silver in a molar ratio of 1: 0.7
Weighed and mixed in a mortar. Pellets the mixture as well
And then sealed in a quartz tube under reduced pressure for 48 hours at 600 ° C.
And then pulverize to 200 mesh or less
_0.7V_TwoO_FiveComposite oxide of silver and vanadium represented by
I got

Using the silver ion conductive solid electrolyte thus obtained and a composite oxide comprising silver and vanadium oxide,
An electrochemical memory device was constructed by the following method. FIG. 2 shows a schematic diagram of the electrochemical memory device.

First, the solid electrolyte and the composite oxide were mixed in a weight ratio.
The mixture was mixed at a ratio of 1: 1 to obtain an electrode material. Next, the solid electrolyte
200 mg was weighed. This solid electrolyte powder was press-formed into a disk shape of 10 mmφ 3, and 20 mg of each of the previously obtained electrode material powders 4 and 5 were pressed and pressed at 4 ton / cm ² on both surfaces thereof. To one of the electrodes thus obtained, a stainless steel piece 6 also serving as a reflector for laser light was adhered with a carbon paste to detect mechanical displacement of the electrochemical memory element,
Further, lead terminals 7 and 8 were attached to form an electrochemical memory device.

Using the electrochemical memory element obtained in this manner, as one of the methods of reading out the stored contents by mechanical displacement of the electrochemical memory according to the present invention, reading using a laser displacement meter (KL13 manufactured by Anritsu) is performed. I did soup. That is, a change in the length of the electrochemical memory element was read as a mechanical displacement by a laser displacement meter. The resolution of this laser displacement meter is 10 nm, and the measurement range is ± 80 μm.

Next, FIG. 3 shows a principle diagram of a method for reading out mechanical displacement in this embodiment. The laser displacement meter used in this embodiment measures the distance to the object to be measured as follows. A laser beam 10 emitted from an infrared laser from a detection unit 9 of the displacement meter is irregularly reflected by a reflector provided on an electrochemical memory element 11 which is an object to be measured. The reflected light passes through the slit in the detection unit, and then reaches the position sensor. By detecting the position where the reflected light arrives by the position sensor, the distance from the detection unit to the object to be measured is calculated, and the output is recorded by the recorder 12 as an analog output. Thus, by measuring the distance from the detection unit of the displacement meter to the upper end of the electrochemical memory element, a change in the length of the electrochemical memory element was calculated. In the figure, 13 is a control unit of the laser displacement meter, and 14 is a potentio galvanostat for driving the electrochemical memory element.

The operation of the electrochemical memory device was performed as follows. First, write 100 μA
Was applied for one minute. After that, the element was opened, and the change over time of the element length was measured by a laser displacement meter. FIG. 4 shows how the resulting element length changes over time. By applying the current pulse, the length of the element becomes
When the device was expanded to 70 nm, and then the device was opened, the expansion did not return, and the length of the electrochemical memory device did not change with time and showed a constant value. When the change in the length of the element over time was continuously measured, no change was observed even after 30 days had passed.

Next, in order to examine the analogity of the memory voltage, a current pulse used for writing was set to 100 μA × 1 mi.
n., 100 μA × 2 min., 100 μA × 3 min., 100 μA
The same measurement was performed with × 4 min. And 100 μA × 5 min. FIG. 5 shows the resulting relationship between the lengthening of the element and the current pulse width. The extension of the length of the memory element and the current pulse width have a substantially proportional relationship, and it has been found that this memory element can be read as an analog memory. Also, when the temporal change of the length of the element was measured continuously,
No change was observed after 30 days, indicating that it could be used as an analog memory.

For comparison, the recorded contents were read by the conventional reading method using this electrochemical memory. As a conventional method of reading stored contents by voltage,
The electrochemical memory element was connected to a pen recorder (input resistance 1 MΩ) and its storage voltage was detected.

The voltage of the electrochemical memory device after the same writing as in the above embodiment was about 1.7 mV. After that, when the voltage of the device was measured continuously, the voltage after 30 days was about 0.8 mV.

From the above, it has been found that, in the conventional method of reading an electrochemical memory element by a voltage, a current flows to an external circuit for reading the voltage, and the stored contents of the element are lost.

From the above, it was confirmed that according to the present invention, it is possible to read out the electrochemical memory element without losing the stored contents. Example 2 Ag _0.7 obtained in Example 1, which is a substance capable of electrochemically transferring ions into and out of ion sites in a lattice, as a substance exhibiting a reversible volume change due to an electrochemical redox reaction. An electrochemical memory device was constructed in the same manner as in Example 1 except that a composite oxide composed of silver and vanadium oxide represented by V ₂ O ₅ and Ag _0.8 V ₂ O ₅ was used, and a laser displacement meter was used. The memory was read by measuring the mechanical displacement of the element.

A composite oxide composed of silver and vanadium oxide represented by Ag _0.8 V ₂ O ₅ was prepared in the same manner as in Example 1 except that the mixing ratio of metallic silver to vanadium oxide was 0.8: 1.

The electrochemical method was performed in the same manner as in Example 1 except that the composite oxide composed of silver and vanadium oxide represented by Ag _0.8 V ₂ O ₅ obtained above was used as the negative electrode active material of the electrochemical memory element. A memory element was constructed, and writing and reading of the memory were performed.

As a result, the stored contents were maintained after 30 days as in Example 1, and it was confirmed that according to the present invention, the electrochemical memory element could be read without losing the stored contents.

Example 3 As a silver ion conductive solid electrolyte composed of silver halide-silver oxyacid, a solid electrolyte mainly composed of silver iodide represented by 5AgI-3Ag ₂ O-2V ₂ O ₅ and silver vanadate An electrochemical memory device was constructed in the same manner as in Example 1 except that the device was used, and the memory was read by measuring the mechanical displacement of the device using a laser displacement meter.

First, the synthesis of a silver ion conductive solid electrolyte will be described. First, AgI, Ag ₂ O, V ₂
O ₅ was weighed to a molar ratio of 5: 3: 2 and mixed in an alumina mortar. After this mixture was heated and melted in a glassy carbon crucible, the melt was directly poured into liquid nitrogen and rapidly cooled. The thus a reaction product obtained by pulverizing the 200 mesh or less in a mortar 5AgI-3Ag ₂ O-
A silver ion conductive solid electrolyte represented by 2V ₂ O ₅ was obtained.

An electrochemical memory device was constructed in the same manner as in Example 1 except that the silver ion conductive solid electrolyte obtained above was used as the solid electrolyte, and writing and reading of the memory were performed.

As a result, the stored contents were maintained after 30 days as in Example 1. According to the present invention, it was possible to read the electrochemical memory element without losing the stored contents.

Example 4 A silver ion conductive solid electrolyte consisting of silver halide-silver oxyacid was used except that a solid electrolyte consisting of silver iodide represented by 3AgI-Ag ₂ MoO ₄ and silver molybdate was used. An electrochemical memory device was constructed in the same manner as in Example 1, and the memory was read by measuring the mechanical displacement of the device using a laser displacement meter.

First, the synthesis of a silver ion conductive solid electrolyte will be described. First, AgI, Ag ₂ MoO ₄
Were weighed so as to have a molar ratio of 3: 1 and mixed in an alumina mortar. Place this mixture in a Pyrex tube at 500 ° C.
After melting for 10 hours, the melt was poured directly into liquid nitrogen and quenched. The reaction product obtained as above is placed in a mortar for 20 minutes.
The mixture was pulverized to 0 mesh or less to obtain a solid electrolyte having silver ion conductivity represented by 3AgI-Ag ₂ MoO ₄ .

An electrochemical memory device was constructed in the same manner as in Example 1 except that the silver ion conductive solid electrolyte obtained above was used as the solid electrolyte, and writing and reading of the memory were performed.

As a result, the stored contents were maintained after 30 days as in the case of Example 1. According to the present invention, it was possible to read out the electrochemical memory element without losing the stored contents.

Example 5 A copper ion conductive solid electrolyte represented by Rb ₄ Cu ₁₆ I ₇ Cl ₁₃ as a solid electrolyte, and ions are electrochemically transferred into and out of ion sites in a lattice as electrode active materials for a positive electrode and a negative electrode. An electrochemical memory device was constructed in the same manner as in Example 1 except that a copper chevrel phase compound represented by Cu ₂ Mo ₆ S _8, which was a substance capable of being used, was used. The memory was read by measuring the target displacement.

The copper ion conductive solid electrolyte represented by Rb ₄ Cu ₁₆ I ₇ Cl ₁₃ is prepared by adding copper (I) iodide (CuI), copper chloride (I) (CuCl), and rubidium chloride (RbCl) to a predetermined amount. Mixed at a reduced rate, sealed in a hard glass tube under reduced pressure, and
It was synthesized by heating for hours.

The copper chevrel phase compound represented by Cu ₂ Mo ₆ S ₈ is prepared by mixing metallic copper, metallic molybdenum, and molybdenum sulfide (MoS ₂ ) at a predetermined ratio, sealing the mixture in a quartz glass tube under reduced pressure, It was synthesized by heating at ℃ for 72 hours.

An electrochemical memory element was constructed in the same manner as in Example 1 except that the copper ion conductive solid electrolyte obtained as described above and a copper chevrel phase compound were used, and writing and reading of the memory were performed. went. However, in order to eliminate the influence of moisture and oxygen in the air, the synthesis of the materials, the configuration of the device, and the evaluation of the characteristics were all performed in a dry Ar atmosphere.

As a result, the stored contents were maintained after 30 days as in the case of Example 1. According to the present invention, the electrochemical memory element could be read without losing the stored contents.

Example 6 Using the silver ion conductive solid electrolyte obtained in Example 1 and a composite oxide composed of silver and vanadium oxide, an electrochemical memory device was constructed in the following manner.

First, a solid electrolyte sheet and an electrode sheet constituting an electrochemical memory element were obtained by the following method. A polyester resin "Vylon 300" (trade name), which is a binder of the solid electrolyte powder, was placed in toluene and dissolved in an ultrasonic cleaner. The silver ion conductive solid electrolyte obtained in Example 1 was added to a toluene solution of the polyester resin at a ratio of 2.5 wt% of the polyester resin to the solid electrolyte, and kneaded in a mortar to obtain a solid electrolyte slurry. did.

A polyester mesh (200 mesh, thickness 80 μm) was immersed in the solid electrolyte slurry, pulled up from the slurry and passed through a squeegee having a slit width of 150 μm as shown in FIG. In FIG. 6, 15 is a polyester mesh, 16 is a solid electrolyte slurry, 17 is a squeegee, 18 is a glass container for storing the slurry, 19 is a roller for pulling up the mesh, and a guide 20. Thereafter, the toluene was evaporated in the air to obtain a solid electrolyte sheet.

Next, the composite oxide obtained in Example 1 and the silver ion conductive solid electrolyte were mixed at a weight ratio of 1: 1 to obtain an electrode material. This electrode material was added to the previously obtained toluene solution of the polyester resin at a ratio of 3 wt% of the polyester resin to the solid electrolyte, and kneaded in a mortar to obtain an electrode material slurry.

This solid electrolyte slurry was converted into a polyester mesh (200 mesh, thickness 80 μm) in the same manner as described above.
To obtain an electrode sheet. However, at this time, the interval between the squeegees 17 was adjusted so that the electrode sheet having a thickness of 100 μm was
An electrode sheet having a thickness of 200 μm was prepared.

The two types of electrode sheets were thermocompression-bonded to both sides of the solid electrolyte sheet obtained as described above,
After cutting, the lead wires 21 and 22 were adhered with a silver paste to form an electrochemical memory device. FIG.
Shown in In the figure, reference numerals 23 and 24 denote electrode sheets having a thickness of 10
The 0 μm electrode sheet 23 is a positive electrode, and the 200 μm thick electrode sheet 24 is a negative electrode. 25 is a solid electrolyte sheet,
26 and 27 are carbon pastes which are current collectors.

Using the electrochemical memory device thus obtained, writing and reading of the memory device were performed in the same manner as in Example 1. FIG. 8 shows a principle diagram of writing and reading of the element.

In the figure, reference numeral 28 denotes the electrochemical memory element obtained above, one end of which is fixed by a clamp 29. Reference numeral 30 denotes a laser displacement meter used in Example 1, which measures a mechanical displacement (bending) of the electrochemical memory element as a distance to one end of the electrochemical memory element that is not fixed. However, in this measurement, the electrode of the electrochemical memory element having a thickness of 100 μm was irradiated with the laser of the displacement meter. Reference numeral 31 denotes a potential for writing to the memory.
Galvanostat.

The writing to the memory was performed by applying a voltage pulse of 200 mV for 1 minute. After that, the element was cut off from the potentio galvanostat and the output of the laser displacement meter was recorded in an open circuit state.

FIG. 9 shows the obtained results. The distance from the detection unit of the laser displacement meter to the electrochemical memory element increased as the voltage was applied.
μm away. After that, when the voltage application was interrupted, the laser displacement meter showed a constant value. When the change in the length of the element over time was continuously measured, no change was observed even after 30 days had passed.

As described above, according to the present invention, it was possible to read out the electrochemical memory element without losing the stored contents. Example 7 An optical memory device was fixed to the electrochemical memory device obtained in Example 6 to construct an electrochemical memory device, and its characteristics were evaluated.

As an optical device fixed to the electrochemical memory device, a reflection plate 33 was formed on the electrochemical memory device 32 constructed in Example 6 as shown in FIG. Reflector 3
Numeral 3 is made of an aluminum thin film, and was constructed by placing an electrochemical memory element 32 in a heating vapor deposition apparatus and heating aluminum by resistance.

An electrochemical memory device as shown in FIG. 11 was constructed using the electrochemical memory element to which the reflector was fixed. In FIG. 11, reference numeral 32 denotes an electrochemical memory element which constitutes the above-described reflector, and is connected to an input terminal 34 for writing data into the memory. Reference numeral 35 denotes a He-Ne laser, whose laser light is fixed so as to be incident on a reflection plate 33 formed on the electrochemical memory element. A line sensor 36 detects a position where the laser beam 37 reflected by the reflection plate is incident, and sends a signal to a personal computer 38 for recording.

The operating characteristics of the electrochemical memory device constructed as described above were examined. As an input signal, a constant voltage of 100 mV was input for 10 minutes. Thereafter, the input terminal was opened, and the change with time of the output signal was measured.

As a result, the irradiation position of the light on the line sensor changed with the application of the voltage, and thereafter the input voltage was interrupted and the input terminal was opened. As a result, the stored data was maintained after 30 days.

For comparison, the recorded contents were read by using the electrochemical memory according to the conventional reading method. As a conventional method of reading stored contents by voltage,
The electrochemical memory element was connected to a pen recorder (input resistance 1 MΩ) and its storage voltage was detected. That is, after performing the same writing as in the above example, a pen recorder was connected to the input terminal of the electrochemical memory device, and the voltage of the electrochemical memory element was measured.

As a result, the voltage of the electrochemical memory element immediately after the voltage input (memory writing) was about 85 mV. Thereafter, when the voltage of the device was measured, the voltage after 30 days was almost 0 mV.

From the above, it has been found that, in the conventional method of reading an electrochemical memory element by a voltage, a current flows to an external circuit for reading the voltage, and the stored contents of the element are lost.

From these results, it was found that according to the present invention, an electrochemical memory device capable of reading an electrochemical memory element without losing stored contents can be obtained.

Example 8 An optical device was fixed to the electrochemical memory device obtained in Example 1 to construct an electrochemical memory device, and its characteristics were evaluated.

FIG. 12 shows the principle of operation of the electrochemical memory device according to the present invention. In this embodiment, a slit 40 was used on the electrochemical memory element 39 as an optical device fixed to the electrochemical memory element 39. This electrochemical memory device further has a slit 41 fixed to the optical table, and light 43 emitted from the light source 42 passes through the slits 40 and 41, and the generated interference fringes are detected by the line sensor 44. It has a structure to do. This storage device
The writing of the memory changes the length of the electrochemical memory element 39, and as a result, the position of the slit 40 changes, so that the position of the interference fringe changes, and the change reads the memory contents.

The writing of the memory into the electrochemical memory device was performed in the same manner as in the seventh embodiment. As a result, the light detection position on the line sensor changes with the application of the voltage, and then the input voltage is interrupted and the input terminal is opened.
The content of the memory was retained even days later.

From these results, it was found that according to the present invention, an electrochemical memory device capable of reading an electrochemical memory element without losing stored contents can be obtained.

Example 9 A pointer was attached to the electrochemical memory device obtained in Example 6,
An electrochemical memory device was constructed.

FIG. 13 is a schematic diagram of the electrochemical memory device constructed in this embodiment. Reference numeral 45 denotes an electrochemical memory element obtained in Example 6, to which a pointer 46 is attached. One end of this element was fixed to an electric quantity display plate 48 with a fixing jig 47, and lead wires 49 and 50 were connected to energization terminals 51 and 52, thereby forming an electrochemical memory device.

The writing of the memory into this electrochemical memory device was performed in the same manner as in the seventh embodiment. As a result, the position indicated by the pointer changed with the application of the voltage, and thereafter, when the input voltage was interrupted and the input terminal was opened, the memory contents were maintained even after 30 days.

From the above, it was found that according to the present invention, it is possible to obtain an electrochemical memory device capable of reading an electrochemical memory element without losing the stored contents.

Example 10 As an example of the present invention, the mechanical displacement of the electrochemical memory element was measured by measuring the atomic force, and the memory was read.

First, as an electrochemical memory device, a thin film memory was constructed by the following method. FIG. 14 is a cross-sectional view of the electrochemical memory device according to the present embodiment. In the figure, 5
No. 3 was formed on a glass substrate 54 by high frequency sputtering.
ITO thin film used as an electrode terminal for electrochemical memory devices. On this ITO thin film, an Ag _0.7 V ₂ O ₅ thin film 55, which is one electrode of the electrochemical memory device, was formed to a thickness of about 0.5 μm by high frequency sputtering. 56
Is an Ag ₆ I ₄ WO ₄ thin film which is a solid electrolyte layer,
Silver iodide (AgI) and silver tungstate (Ag ₂ W
The mixture was formed by a flash evaporation method using the mixture of O ₄ ) as an evaporation source. Thereafter, an Ag _0.7 V ₂ O ₅ thin film 57 was deposited to a thickness of about 0.5 μm as another electrode facing the electrode 55 by a high frequency sputtering method. Further, a Pt thin film 58 was formed thereon as a current collector by electron beam evaporation.

Using the electrochemical memory element, the atomic force was measured to read the electrochemical memory element. The atomic force was measured using a commercially available atomic force microscope. FIG. 15 is a diagram illustrating the principle of the reading method according to the present embodiment. In the figure, 59 is the electrochemical memory element obtained above, and 60 is the probe of the atomic force microscope. The probe 60 is moved by piezo actuators 61, 62 and 63.
It can be moved in each of the three dimensions of X, Y, and Z. The voltage of the piezo actuator 63 in the Z direction is fed back by measuring the atomic force between the probe 60 and the sample to be measured (electrochemical memory element), and the distance between the probe and the electrochemical memory element is constant. It works to become.
Further, the electrochemical memory element was connected to a potentio galvanostat 66 by lead terminals 64 and 65, and writing of the memory was performed by the potentiogalvanostat.

Using this apparatus, the mechanical displacement of the electrochemical memory device was measured as follows. The piezo actuators in the X and Y directions for controlling the scanning of the probe were not operated, and the probe always pointed to a certain position of the electrochemical memory device. The piezo actuator in the Z direction was operated by applying a voltage so that the interatomic force acting between the electrochemical memory element and the probe became constant. The voltage applied to the piezo corresponds to the distance from the probe to the electrochemical memory element. By recording this voltage, it is possible to read out the mechanical displacement (elongation / shrinkage) of the electrochemical actuator. it can.

Using this apparatus, writing / reading of an electrochemical memory element was performed. Writing was performed by applying a constant voltage pulse of 100 mV with a pulse width of 1 second. Thereafter, the potentio galvanostat was cut off from the device, and the device was opened. Z associated with this operation
FIG. 16 shows the result of recording the change in the voltage of the piezo actuator in the direction using the transient memory. It can be seen that the voltage of the piezo actuator is reduced by the application of the constant voltage pulse, and the thickness of the electrochemical memory element is increased. Even after the application of the voltage is stopped and the memory element is opened, the voltage applied to the actuator shows a substantially constant value. In addition, as a result of continued measurement,
Even after a day, there was no significant change in the voltage applied to the actuator, indicating that the electrochemical memory element retained the stored contents. Using this electrochemical memory for comparison,
The recorded contents were read by a conventional reading method. As a conventional method of reading stored contents by voltage, an electrochemical memory element was connected to a pen recorder (input resistance 1 MΩ), and the stored voltage was detected.

The voltage of the electrochemical memory device after the same writing as in the above embodiment was about 89 mV. After that, when the voltage of the device was measured, the voltage was almost 0 mV after 3 days.

From the above, it has been found that in the conventional method of reading an electrochemical memory element using a voltage, a current flows through an external circuit for reading the voltage, and the stored contents of the element are lost.

From these results, it was found that according to the present invention, it is possible to read out the electrochemical memory element without losing the stored contents. Example 11 As an example of the present invention, the mechanical displacement of the electrochemical memory element was measured by measuring the tunnel current, and the memory was read.

The electrochemical memory device in this embodiment is
The one obtained in Example 10 was used. A commercially available scanning tunneling electron microscope was used for measuring the tunnel current.
FIG. 17 is a diagram illustrating the principle of the reading method according to the present embodiment. In the figure, reference numeral 67 denotes an electrochemical memory element used in this embodiment, and reference numeral 68 denotes a probe of a scanning tunneling electron microscope. The probe 68 is a piezo actuator 69, 70,
71 allows movement in the three-dimensional directions of X, Y, and Z. Reference numeral 72 denotes a sample holder of the scanning tunneling electron microscope, which is connected to the probe 68 via a power source 73, and is connected between the probe 68 and a Pt film which is a current collector of the electrochemical memory element. A current can flow. Feedback is applied to the voltage of the piezo actuator 71 in the Z direction by measuring the atomic force between the probe 68 and the sample to be measured (electrochemical memory element), so that the distance between the probe and the electrochemical memory element is constant. It works to become. The electrochemical memory element is connected to a potentio galvanostat 76 by lead terminals 74 and 75,
Writing to the memory was performed using this potentio galvanostat.

Using this apparatus, the X and Y piezo actuators for controlling the scanning of the probe so that the probe always measures the distance to a certain place of the electrochemical memory element are not operated, and the Z direction is not operated. A voltage was applied to only the piezo actuator so that a tunnel current flowing between the electrochemical memory element and the probe was constant, and the piezoelectric actuator was operated. The voltage applied to the piezo corresponds to the distance from the probe to the electrochemical memory element, and by recording this voltage, the mechanical displacement (elongation / shrinkage) of the electrochemical actuator can be known. .

Using this apparatus, writing and reading of an electrochemical memory element were performed in the same manner as in Example 10. As a result, the voltage of the piezo actuator was reduced by the application of the constant voltage pulse, and the voltage applied to the actuator showed a substantially constant value even after the application of the voltage was stopped and the memory element was opened. In addition, as a result of continuous measurement, it was found that the voltage applied to the actuator did not change significantly after 3 days.

As described above, according to the present invention, it was found that the reading of the electrochemical memory element could be performed without losing the stored contents. In the examples of the present invention, only those using a solid electrolyte as the electrochemical memory element have been described, but a liquid electrolyte is used as long as it causes mechanical displacement of the electrode due to the electrochemical reaction. Needless to say, the same effect can be obtained as long as it is a device. For example, it is needless to say that the same result can be obtained by using the mechanical displacement of the hydrogen storage alloy electrode in a nickel-hydrogen storage battery, and the present invention is applicable to an electrochemical memory device using the solid electrolyte described in the examples. It is not limited only.

Further, in the embodiments of the present invention, a solid electrolyte used for an electrochemical memory device using a silver ion conductive solid electrolyte or a copper ion conductive solid electrolyte has been described. Needless to say, the same results can be obtained for those using other solid electrolytes such as conductive solid electrolytes, or those using other solid electrolytes as electrochemical memory elements. The present invention is not limited only to the electrochemical memory elements described in these examples.

In the examples of the present invention, halogen
As a silver ion-conducting solid electrolyte of silver halide-silver oxyacid system
4AgI-Ag_TwoWO_Four, 5AgI-3Ag_TwoO-2V
_TwoO _Five, 3AgI-Ag_TwoMoO_FourSilver ion represented by
Explained the use of conductive solid electrolyte
However, those with different composition ratios of these solid electrolytes, such as
If 3AgI-Ag_FourSiO_Four, AgI-Ag_TwoO-2B
_TwoO_ThreeIncluding other metal oxides or silver oxyacid, or
AgI-Ag_TwoO-WO_Three-B_TwoO_ThreeFour-component system such as
AgCl-Ag_TwoWO_FourHaloge other than silver iodide such as
A similar effect can be obtained for those containing silver halide.
Needless to say, the present invention relates to the solids described in these examples.
It is not limited to the electrolyte.

In the embodiment of the present invention, silver represented by Ag _0.7 V ₂ O ₅ or Ag _0.8 V ₂ O ₅ and vanadium oxide are used as electrode active materials when a silver ion conductive solid electrolyte is used as the electrolyte. An example using a composite oxide made of a material is described, but furthermore, a composite oxide having a different silver ion concentration or a silver ion such as silver selenide, silver selenide-silver phosphate solid solution, niobium disulfide, and metallic silver is used. Needless to say, the same effect can be obtained for other active materials acting as an active material for the conductive solid electrolyte.
The present invention is not limited to the electrode active materials described in these examples.

Further, in the embodiments of the present invention, the description has been made of the reflector or the slit as the optical device fixed to the electrochemical memory element. However, similar effects can be obtained by using other optical devices such as a prism. Needless to say, the present invention is not limited to the optical devices described in the examples as the optical device fixed to the electrochemical memory element.

[0122]

As described above, according to the present invention, the information of the electrochemical memory element is read out by the mechanical displacement of the electrochemical memory element, so that the information of the electrochemical memory element is discharged by an external load. The stored contents of the electrochemical memory element can be read out without losing the stored contents.

[0123]

[Brief description of the drawings]

FIG. 1 is a principle diagram of a reading method of an electrochemical memory element using an optical system.

FIG. 2 is a configuration diagram of an electrochemical memory device according to one embodiment of the present invention.

FIG. 3 is a block diagram of a system for reading an electrochemical memory device according to an embodiment of the present invention.

FIG. 4 is a graph showing operating characteristics of an electrochemical memory device according to an embodiment of the present invention.

FIG. 5 is a diagram showing a pulse width of a write current pulse of an electrochemical memory and a read result of the memory according to an embodiment of the present invention.

FIG. 6 is a principle diagram of an apparatus for producing a solid electrolyte sheet and an electrode sheet used in an electrochemical memory element according to one embodiment of the present invention.

FIG. 7 is a sectional view of an electrochemical memory device according to an embodiment of the present invention.

FIG. 8 is a principle diagram of writing / reading of the electrochemical memory element in one embodiment of the present invention.

FIG. 9 is a view showing a reading result of an electrochemical memory device according to one embodiment of the present invention.

FIG. 10 is a principle view of an electrochemical memory device.

FIG. 11 is a principle view of an electrochemical memory device.

FIG. 12 is an operation principle diagram of an electrochemical memory device according to an embodiment of the present invention.

FIG. 13 is a schematic view of an electrochemical memory device according to an embodiment of the present invention.

FIG. 14 is a cross-sectional view of an electrochemical memory device according to an embodiment of the present invention.

FIG. 15 is a principle diagram of reading of an electrochemical memory element according to an embodiment of the present invention.

FIG. 16 is a diagram showing a reading result of an electrochemical memory device according to one example of the present invention.

FIG. 17 is a principle diagram of reading of an electrochemical memory element according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrochemical memory element 2 Reflector 3 Solid electrolyte 4,5 electrode 6 Stainless steel piece 7,8 lead terminal 9 Detection part of laser displacement meter 10 Laser beam 11 Electrochemical memory element 12 Recorder 13 Control part of laser displacement meter 14 Potency Ogalvanostat 15 Polyester mesh 16 Solid electrolyte slurry 17 Squeegee 18 Glass container 19 Roller 20 Guide 21, 22 Lead wire 23, 24 Electrode sheet 25 Solid electrolyte sheet 26, 27 Current collector 28 Electrochemical memory element 29 Clamp 30 Laser displacement meter Detection unit 31 potentio galvanostat 32 electrochemical memory element 33 reflector 34 input terminal 35 He-Ne laser 36 line sensor 37 laser beam 38 personal computer 39 electrochemical memory element 40 fixed to electrochemical memory element The slit 41 slit 42 light source 43 light 44 line sensor 45 electrochemical memory device 46 Guidance 47 fixing jig 48 panel 49, 50 leads 51 energized terminals 53 ITO film 54 glass substrate 55 Ag _0.7 V ₂ O ₅ thin film 56 AG ₆ I ₄ WO ₄ thin film 57 Ag _0.7 V ₂ O ₅ thin film 58 Pt thin film 59 electrochemical memory element 60 probe 61, 62, 63 piezo actuator 64, 65 lead terminal 66 potentiogalvanostat 67 electrochemical memory element 68 probe 69, 70, 71 Piezo actuator 72 Sample holder 73 Control power supply 74, 75 Lead terminal 76 Potentiio galvanostat

Continuation of front page (56) References JP-A-56-153577 (JP, A) JP-A-59-19863 (JP, A) JP-A-59-23260 (JP, A) JP-B-43-17275 (JP, A) , B1) (58) investigated the field (Int.Cl. ^7, DB name) G11C 11/21 G11C 13/02 G11C 27/00 G01R 22/02 JICST file (JOIS) WPI (DIALOG)

Claims (8)

(57) [Claims] And 1. A solid electrolyte, a readout device electrochemical memory device having at least a at least a pair of electrodes disposed by interposing the solid electrolyte, the information of the electrochemical memory device, the electrical An apparatus for reading an electrochemical memory element, comprising: means for reading by mechanical displacement of the chemical memory element. 2. The means for reading by the mechanical displacement of the electrochemical memory element is any one selected from an optical system reading means, an atomic force measurement reading means, and a tunnel current measurement reading means. 2. An apparatus for reading an electrochemical memory element according to claim 1. 3. The reading device for an electrochemical memory device according to claim 1, wherein at least one pair of electrodes includes a substance that exhibits a reversible volume change accompanying an electrochemical redox reaction. 4. The electrochemical memory according to claim 3, wherein the substance exhibiting a reversible volume change accompanying the electrochemical oxidation-reduction reaction is a substance that electrochemically moves ions into and out of ion sites in a lattice. Element reading device. 5. The reading device for an electrochemical memory device according to claim 1 , wherein the solid electrolyte is a silver halide-silver oxyacid-based silver ion conductive solid electrolyte. 6. The reading of the electrochemical memory element according to claim 4, wherein the substance capable of taking ions in and out of the lattice is a composite oxide composed of a transition metal oxide containing at least silver and vanadium oxide. apparatus. 7. The reading device for an electrochemical memory device according to claim 1, wherein the pair of electrodes are arranged to face each other with the electrolyte layer interposed therebetween. 8. A electrochemical memory device, a fixed pointer or fixed optical device according to claim 1 provided that,
The reading device for an electrochemical memory device according to any one of claims 7 to 10.