JPH0338076A - Electrostriction effect element and its manufacture - Google Patents

Abstract

PURPOSE:To make it possible to obtain a large amount of displacement in a low voltage by a method wherein an insulating layer consisting of a polyimide resin hating a specified repeat unit is formed only on the exposed part, which is located on the side end surface of an element, of an internal electrode plate and an electrostriction material in the vicinity of the exposed part. CONSTITUTION:The end surface of an internal electrode plate is exposed on the side end surface of an element and an insulating layer consisting of a polyimide resin having a repeat unit, which is shown in a formula (I), is formed only on the exposed part, which is located on the side end surface of the element, of the internal electrode plate and an electrostriction material in the vicinity of the exposed part. In the formula (I), X is a quadrivalent group, such as a phenyl group, a biphenyl group or the like, and Y is a dihydric group, such as a phenyl group, an alkylene group or the like. Thereby, it becomes possible to lessen an interlayer distance and a laminated electrostruction effect element capable of obtaining a large amount of displacement in a low voltage can be obtained.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a laminated electrostrictive element that produces a large amount of displacement at low voltage and has an extremely small distance between the eyebrows, and a method for manufacturing the same.

[Prior art J] Conventional 1 actuators include motors that operate using electromagnetic force, those that convert the rotation of this electromagnetic motor into linear motion using a combination of gears, and voice coils that combine an electromagnetic coil and a spring. It is representative. These actuators are widely used in all types of machinery for high-speed continuous rotation and positioning, but in recent years, the need for new conversion elements has rapidly increased, mainly in fields such as optical precision machinery and semiconductor devices. There is. For example, requirements for processing accuracy in optical equipment such as lasers and cameras, and positioning accuracy in semiconductor manufacturing equipment, as well as requirements for adjusting optical path length in optics and astronomy, have already reached a level of 1 micron or less, and these requirements will continue to increase in the future. It is clear that things are becoming more and more severe. Recently, actuators that use piezoelectric and electrostrictive effects have suddenly been in the spotlight as new actuators that do not use electromagnetic force, and there are great expectations for their future potential in expanding new genres in the electronics ceramics market. It is being Conventionally, an electrostrictive effect element having a multilayer chip capacitor structure has been manufactured by the following method. First, mix the raw material composition,
After calcining, a suitable binder and solvent are mixed with the calcined powder, and a thin film is formed using this mixture by a doctor blade method. Metal electrodes are printed on this thin film and laminated. A plurality of metal electrode plates in this laminate are connected to external electrodes every other time, so that one system is positive and the other system is negative. In this manufacturing method, the area of the overlapping portion of the positive and negative electrode plates must be smaller than the total cross-sectional area, and therefore, there is a portion where the electrode plates do not overlap at the periphery. When a voltage is applied between the electrode plates of such an electrostrictive element, the electric field strength increases in the part where the electrode plates overlap, but the electric field strength in the peripheral part is weak, so the amount of displacement in the peripheral part becomes small, This has the disadvantage that the amount of displacement of the entire element is smaller than desired. Further, due to this, stress concentration occurs at the boundary between the deformed part and the non-deformed part, and there is a drawback that the element itself is destroyed due to long-term application or repeated application. Therefore, it is difficult to use the conventional manufacturing method of multilayer chip capacitors as is. As a method to eliminate the above drawbacks,
No. 115579 discloses an electrostrictive effect characterized in that an inorganic insulating layer is formed on the entire surface or every other layer of an electrode exposed on a side end surface of a laminated electrostrictive effect element using an electrophoresis method. A method of manufacturing the device is disclosed. When such a manufacturing method is used, the above-mentioned drawbacks are eliminated. However, in order to prevent the insulating layer from interfering with the electrostrictive effect or destroying the insulating layer itself, it is most preferable that the insulating material be attached only near the electrodes on the side end surfaces of the laminated electrostrictive element. Since the inorganic insulating layer has good compatibility with the ceramic body, it adheres over a wide range, so the distance between the eyebrows must be set to 100 microns or more so that the insulating layers attached to each electrode exposed on the side end face are not continuous with each other. However, if the distance between the eyebrows is 100 microns or more, a high voltage of 100V is required to apply an electric field of 10 kV/cm to this electrostrictive element. [Problem to be Solved by the Invention J] In recent years, there has been a demand for electrostrictive elements that can be driven at low voltage and have a large amount of displacement, so it is clear that it is preferable that the distance between layers be small. However, as mentioned above, as long as an inorganic insulator is used, the distance between the eyebrows is limited to 100 microns. Also, the above-mentioned Japanese Patent Application Laid-Open No. 59-11557
Publication No. 9 states that insulation using organic materials has poor adhesion to ceramics, metals, etc., and has been difficult to put into practical use as insulation for electrostrictive elements to which a high electric field is applied. A laminated electrostrictive element capable of obtaining a large amount of displacement with such a low voltage and a method for manufacturing the same have not yet been put to practical use. The purpose of the present invention is to utilize organic insulators and increase the interlayer distance to 10
It is an object of the present invention to provide a laminated electrostrictive element and a method for manufacturing the same, in which the thickness can be set to 100 microns, thereby allowing a large amount of displacement at low voltage. [Means for Solving the Problems 1] The present invention has been made to achieve the above object, and the electrostrictive effect element of the present invention has a film or thin plate of electrostrictive material and an internal electrode plate alternately. It is an electrostrictive effect element laminated on the inner electrode plate, and the end face of the internal electrode plate is exposed on the side end face of the element, and the exposed part of the circular electrode plate on the side end face and the electric current in the vicinity are The general formula (1) (wherein, X is a phenyl group; a biphenyl group; and at least one of the phenyl group and the biphenyl group is 0, C02S,
A tetravalent group selected from the group consisting of polyphenyl groups bonded by at least one of CHm, C(CHm)* and C(CFs)*, and Y is a phenyl group; a biphenyl group; a phenyl group and a biphenyl group. At least one of the groups is selected from the group consisting of a polyphenyl group bonded by at least one of 0, CO, S, SOx, CHx, C(CHs)* and c(cFs)a; an alkylene group; and a xylylene group The invention is characterized in that an insulating layer of polyimide resin having a repeating unit represented by (a divalent group) is formed. The manufacturing method of the present invention for manufacturing the above-mentioned electrostrictive effect element is such that the end face of the internal electrode plate is attached to the side end face of the electrostrictive effect element in which films or thin plates of electrostrictive material and internal electrode plates are alternately laminated. The exposed electrostrictive element is expressed by the general formula (II) (wherein, X is a phenyl group; a biphenyl group; and at least one of the phenyl group and the biphenyl group is 0, C01S,
A tetravalent group selected from the group consisting of a polyphenyl group bonded by at least one of CHx, C(CHs)a and C(CFs)*, and Y is a phenyl group; a biphenyl group; a phenyl group and a biphenyl group. At least one of the groups is 0, CO1S, SOx, CH,, C(CHs)*
and a polyphenyl group; an alkylene group; and a divalent group selected from the group consisting of a xylylene group) bonded by at least one of C(CFI) and carboxyl of a polyamic acid resin. The electrostrictive element is immersed in an electrophoresis bath for film formation obtained by neutralizing the group with a base and diluting with water, and electrophoresis is performed using the internal electrode plate of the electrostrictive element as an anode. The polyamic acid is precipitated only on the exposed portion of the internal electrode plate on the side end face and its vicinity to form a coating layer, and then heat-treated to imidize the polyamic acid resin of the coating layer to form a polyamic acid resin of the general formula (I). ) (wherein X and Y are as described above) is characterized by forming an insulating layer of polyimide resin having a repeating unit represented by the above formula. A part of the polyamic acid resin used in the production method of the present invention may be imidized in advance. In the above polyimide resin having a repeating unit represented by the general formula (I) and the polyamide resin having a repeating unit represented by the general formula (II), specific examples of X include the following: Specific examples include the following: General formula (
From the viewpoint of adhesion and heat resistance of the polyimide resin having the repeating unit represented by
It is particularly preferred that Y is . The general formula (II) used in the production method of the present invention
) A polyamic acid resin having a repeating unit represented by the general formula (III) (wherein, X is as described above) and a tetracarboxylic acid anhydride having the general formula () 1. Y is as described above). Examples of the above-mentioned tetracarboxylic anhydrides include pyromellitic dianhydride, 3.3°, 4.4°-benzophenonetetracarboxylic dianhydride, 2.2"; 3.3°-benzophenonetetra carboxylic dianhydride,
3.3°14,4°-biphenyltetracarboxylic dianhydride, 2.2°,3,3°-biphenyltetracarboxylic dianhydride, 2.2-bis(3,4-dicarboxyphenyl)brovani anhydride, 2,2-bis(2,3-dicarboxyphenyl)brovani anhydride, bis(3,4-
dicarboxyphenyl)ether dianhydride, bis(3,
4-dicarboxyphenyl)sulfone dianhydride, 1.
．． 1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxydiphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,3,6. 7-Naphthalenetetracarboxylic dianhydride, 1,4,5.8-naphthalenetetracarboxylic dianhydride, 1,2,5.6-naphthalenetetracarboxylic dianhydride, 1,2,3゜4- 'Benzenetetracarboxylic dianhydride, 3,4,9゜O-perylenetetracarboxylic dianhydride, 2,3,6゜7-anthracenetetracarboxylic dianhydride% L2, 7.8-phenanthrenetetra Preferred examples include carboxylic dianhydrides. Among these, particularly preferred tetracarboxylic dianhydride is pyromellitic dianhydride, 3.3°
, 4.4°-benzophenonetetracarboxylic dianhydride, 3.3°, 4°4°-bif-nyltetracarboxylic dianhydride, and bis(3,4-dicarboxyphenyl)
It is an ether dianhydride. The above diamines include 3,3°-diaminobenzophenone, 1,3-bis(3-aminophenoxy)benzene, 4.4°-bis(3-aminophenoxy)biphenyl, 2.2-bis[4- (3-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, bis(4-(3 -aminophenoxy)phenyl] sulfide, bis[4-(3-aminophenoxy)phenyl 1 ketone, bis(4-(3-aminophenoxy)phenyl]sulfone, etc.), and these diamines may be used alone. or a mixture of two or more. The reaction between the above-mentioned tetracarboxylic anhydride and diamine is usually carried out in an organic solvent. Examples of the organic solvent include N-methyl-2-pyrrolidone, N-methyl-2-pyrrolidone, N-methyl-2-pyrrolidone, , N-dimethylacetamide, N,N-dimethylformamide, 1.3-
Dimethyl-2-imidazolidinone, N,N-diethylacetamide, N,N-dimethylmethoxyacetamide, dimethylsulfoxide, pyridine, dimethylsulfone, hexamethylphosphoramide, tetramethylurea, N
-Methylcaprolactam, tetrahydrofuran, m-dioxane, p-dioxane, 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2- Examples include methoxyethoxy)ethyl 1 ether. These organic solvents may be used alone or in combination of two or more.The reaction temperature is usually 200°C or lower - 20°C or higher, preferably 50°C or lower - 10°C or higher, and more preferably 0°C or higher. The reaction pressure, which is about room temperature, is not particularly limited, and can be sufficiently carried out at normal pressure.The reaction time may vary depending on the type of solvent, reaction temperature, and diamine or acid dianhydride used, but the reaction time is sufficient to complete the production of polyamic acid. Generally, 2 to 40 hours, preferably 4 to 24 hours, is sufficient for the reaction. The polyamic acid solution obtained in this way contains 5% polyamic acid.
It is a solution containing ~40% by weight, particularly preferably 10~30% by weight, and has a logarithmic viscosity of 0.5~4dl/g (35°C
, temperature 0.5 g/ml %N, value measured with N-dimethylacetamide), particularly preferably 0.6 to 2.5 dl
/g indicates the water solubility described below. It is also desirable because the polyimide film has excellent physical properties after heat treatment. In the production method of the present invention, the polyamic acid resin having the repeating unit represented by the general formula (II) is added with a base such as an amine or an alkali metal ion in the presence of water, so that the C0OH group is converted into a C00- ion. It can be dissociated into water and become soluble in water, or it can be stably colloidally dispersed, and it can be deposited on the laminated electrostrictive element, which is an anode, by electrophoresis, and can be made insolubilized. The above bases include ammonia: dialkylamine,
Secondary amines such as jetanolamine and morpholine Tertiary amines such as nitriethylamine, tributylamine, triethanolamine, triisopropanolamine, dimethylethanolamine, dimethylisopropanolamine, diethylethanolamine, and dimethylbenzylamine: caustic soda, caustic potassium Inorganic bases such as these are used, but tertiary amines are particularly preferred from the viewpoint of stability after dilution with water and the properties of the resulting film. The amount of base necessary to impart water dilutability is generally 30 to 110 mol%, particularly preferably 40 to 100 mol%, based on the carboxyl equivalent of the polyamic acid to be neutralized. By neutralizing the polyamic acid, the polyamic acid becomes completely water-soluble or partially water-soluble, becoming suspended and dilutable with water. In either case, by neutralizing the polyamic acid and diluting it with water to the following resin concentration,
An electrophoresis bath for forming a film can be made of an aqueous polyamic acid solution that can be subjected to electrophoresis treatment. The polyamic acid resin thus precipitated is converted into a polyimide resin having a repeating unit represented by the general formula (1) (wherein X is as described above) by heat treatment. The polyimide resin insulating layer obtained as described above has an insulating layer thickness of about 50 μm, a dielectric strength of 10 OOv or more, and excellent adhesion to metals. In addition, the wettability with ceramics, which has been a problem until now, is lower than that of inorganic insulating layers, so the insulating layer adheres only to the vicinity of the side edges, making it possible to make the distance between the layers much smaller than with conventional methods. be. Example 1 In a reaction vessel equipped with a stirrer, reflux condenser and nitrogen inlet tube, 53.0 g of 3.3°-diamino, benzophenone
(0.25 mol) to N,N-dimethylacetamide 24
It was dissolved in 0 and 1. To this solution was added 78.6 g (0
, 244 mol) was added thereto and stirred at 10° C. for 24 hours to obtain a polyamic acid solution. The logarithmic viscosity of the obtained polyamic acid was 0.6 dl/g. 39.1 g of dimethylethanolamine (carboxyl equivalent: 90 mol%) was gradually added to this polyamic acid solution, and after stirring at room temperature for 20 minutes, 905.3 g of water was gradually added at room temperature while stirring to dilute with water. A polyamic acid aqueous solution was prepared by
resin concentration 10% by weight). In addition, samples of the laminate were prepared in advance such that metal electrodes were exposed on every other layer on one end surface and all metal electrodes were exposed on the other end surface. - Silver electrodes were baked on the side where the metal electrodes were exposed every other layer, and lead wires were connected with solder. The aqueous solution was put into a plastic tank to serve as an electrophoresis bath for film formation, and the laminate to be coated was infiltrated as an anode, and a lead wire was connected to the anode. 2 in 1OOv
Electrophoresis was performed by applying a voltage for 0 seconds. Thereafter, the laminate was taken out, washed with water, and then dried and imidized by heat treatment at 150°C for 2 hours and 280°C for 2 hours.The laminate was cut in the middle, and a silver electrode was attached to the side where the imide resin insulating film was attached. I applied it and attached the lead wire. By performing the same operation, a laminate having insulating layers on the left and right sides of each electrode was obtained. The thickness of this insulating layer is about 50 microns, and the dielectric strength is 10
It was confirmed that the voltage was 00V or more. Example 2 In a container equipped with a stirrer, a reflux condenser and a nitrogen inlet tube, 2
．． 2-bis(4-(3-aminophenoxy)phenyl)
Propane 41. Og (0.1 mol) and 200 ml of N,N-dimethylacetamide were charged, cooled to around 0°C, and pyromellitic dianhydride 21
．． 8 g (0.1 mol) of powder was added and stirred at around 0°C for 2 hours.Then, the above solution was returned to room temperature and stirred for about 20 hours under a nitrogen atmosphere. The logarithmic viscosity of the polyamic acid thus obtained was 1.5 dl/g. To this polyamic acid solution, 20.2 g of triethylamine (carboxyl equivalent: 100 mol%) was gradually added and stirred at room temperature for 1 hour, and then 973 g of water was gradually added with stirring to dilute it to prepare a polyamic acid aqueous solution (resin (concentration 5% by weight)
. A sample of a laminate was prepared in the same manner as in Example 1, and an insulating layer was provided in the same manner as in Example 1 using this sample and the above polyamic acid aqueous solution. This insulating layer has a thickness of 50μ and t
It had a dielectric strength of ooov or more. Example 3 In a container equipped with a stirrer, a reflux condenser and a nitrogen inlet tube, two
．． 2-bis[4-(3-aminophenoxy)phenyl]
Propane 41. Add Og (0.1 mol) and 219.6 g of N,N-dimethylacetamide, and add 31.6 g of 4.4'-benzophenonetetracarboxylic dianhydride at room temperature under a nitrogen atmosphere. , 098 mol) as a dry solid was added little by little while being careful not to increase the solution temperature, and the mixture was reacted at room temperature for 23 hours. The logarithmic viscosity of the polyamic acid thus obtained was 0.70 dl/g. Triethanolamine 14.
6 g (carboxyl equivalent: 50 mol%) was gradually added, stirred at 40°C for 2 hours, and diluted by gradually adding 117.2 g of water with stirring to prepare an aqueous polyamic acid solution (
resin concentration 15% by weight). A sample of a laminate was prepared in the same manner as in Example 1, and an insulating layer was provided in the same manner as in Example 1 using this sample and the above polyamic acid aqueous solution. This insulating layer has a thickness of 50μ
It had a dielectric strength of 0OOV or more. Examples 4 to 19 Changing the type and amount of diamine, the amount of N,N-dimethylacetamide, the type and amount of tetracarboxylic dianhydride, the amount of dimethylethanolamine used for neutralization, and the amount of water used for dilution All other operations were the same as in Example 1. In addition, the amount of dimethylethanolamine used for neutralization is calculated from the carboxyl equivalent of 90% by weight,
The amount of water used for dilution was calculated to give a resin concentration of 10% by weight. In the table, PMDA is pyromellitic anhydride, and BTDA is 3.3°, 4.4°-benzophenone tetracarboxylic acid. Acid dianhydride, 0DPA is bis(3
,4-dicarboxyphenyl)ether dianhydride, BP
DA represents 3,3°,4,4'-biphenyltetracarboxylic dianhydride. In both cases, the insulating layer had a thickness of 50 μm and a dielectric strength of 1000 V or more. [Effects of the invention] According to the present invention, it has been impossible to reduce the thickness of one layer of a laminate to 100 microns or less, but it can be
It became possible to make it OO micron. Furthermore, until now, organic materials have not attracted attention due to their poor insulation properties, but surprisingly, when polyimide resins are used, their insulating strength has increased to a level comparable to that of inorganic materials.

Claims (2)

[Claims] 1. An electrostrictive effect element in which films or thin plates of electrostrictive material and internal electrode plates are alternately laminated, and the end face of the internal electrode plate is exposed on the side end face of the element, and the end face of the internal electrode plate is exposed on the side end face of the element. General formula (I) ▲Mathematical formula, chemical formula, table, etc. are provided only on the exposed part of the internal electrode plate and the electrostrictive material in the vicinity▼ (wherein, X is a phenyl group; a biphenyl group; and a phenyl group and a biphenyl group) At least one of the groups is O, CO, S,
CH_2, C(CH_3)_2 and C(CF_3)_2
is a tetravalent group selected from the group consisting of polyphenyl groups bonded by at least one of the following, Y is a phenyl group; a biphenyl group; at least one of the phenyl group and the biphenyl group is O, CO, S, SO_2 , CH_2, C(C
A polyimide resin having a repeating unit represented by An electrostrictive effect element characterized by comprising an insulating layer formed thereon. 2. An electrostrictive element in which films or thin plates of electrostrictive material and internal electrode plates are alternately laminated, and the end face of the internal electrode plate is exposed at the side end face of the electrostrictive element is expressed by the general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, X is a phenyl group; a biphenyl group; and at least one of the phenyl group and biphenyl group is O, CO, S,
CH_2, C(CH_3)_2 and C(CF_3)_2
a tetravalent group selected from the group consisting of polyphenyl groups bonded by at least one type, Y is a phenyl group;
Biphenyl group; At least one of phenyl group and biphenyl group is O, CO, S, SO_2CH_2, C(CH_
2) A polyamic acid having a repeating unit represented by a divalent group selected from the group consisting of a polyphenyl group; an alkylene group; and a xylylene group bonded by at least one of _2 and C(CF_3)_2. The carboxyl groups of the resin are neutralized with a base, and the resin is immersed in an electrophoresis bath for forming a film obtained by diluting with a base, and electrophoresis is performed using the internal electrode plate of the electrostrictive element as an anode. The polyamic acid is deposited only on the exposed portion of the internal electrode plate on the side end surface of the effect element and its vicinity to form a coating layer, and then heat treatment is performed to imidize the polyamic acid resin of the coating layer. A claim characterized by forming an insulating layer of polyimide resin having a repeating unit represented by formula (I) ▲A mathematical formula, a chemical formula, a table, etc.▼ (wherein X and Y are as described above) 1. A method for manufacturing an electrostrictive element according to 1.