JPH03142888A - Manufacture of laminated piezoelectric ceramic element - Google Patents

Abstract

PURPOSE:To make it possible to manufacture laminated piezoelectric ceramic elements which transfer at a right angle to their lamination direction by laminating a thermistor material having a negative temperature characteristic and a piezoelectric ceramic material in sheet shape alternately, then calcining them in one piece, and then polarizing the calcined body at a specified temperature. CONSTITUTION:A piezoelectric ceramic layer 12 made of a vanadium oxide ceramic material, which reduces electric resistance drastically and turns into an electric conductor at a specified temperature higher than a curing temperature of a piezoelectric ceramic material which comprises lead titanate zirconate ceramic material and an internal electrode layer 14, is molded in sheet shape at a specified thickness respectively. They are heated, contact bonded and calcined in one piece after the lamination. Then, polarization treatment is carried out in an oil bath 22 by an polarization power supply 24. When an attempt is made to define the temperature of oil 20 higher than the aforesaid specified temperature and lower than the curing temperature of the layer 12, the layer 14 will turn into an insulator at an ordinal service temperature of an element 10 and function only as a bonding layer for the layer 12.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a method for manufacturing a laminated thermistor element. [Prior Art J Conventionally, a thermistor element has been used as a cutter for ink jets, ultrasonic motors, etc., but one type of thermistor element is a combination of a thermistor layer and an internal electrode layer. J1 employment 1 contracted company, b
In addition, when manufacturing such a laminated thermistor element, Kinhayabusa molds the thermistor material into a sheet and prints metal electrode material on one or both sides of the sheet. After stacking multiple pieces and pressing them together, they are fired as a single piece to make ceramics.
Thereafter, a pair of external electrodes connected to the metal electrode material every other layer is formed on the side surface of the fired body, and the fired thermistor is polarized using the external electrodes. . According to this manufacturing method, compared to the case where multiple electrodes are coated on pre-fired thermistor thin plates and polarized and bonded together with adhesive, there are fewer manufacturing steps and productivity is greatly improved. , it is possible to enjoy various excellent effects such as being able to make the thermistor layer thinner and lowering the polarization voltage. You can enjoy the excellent effects of [Problems to be Solved by the Invention] However, in the multilayer thermistor element manufactured by this manufacturing method, due to the presence of the internal electrode layer, the voltage for performing the polarization process and the voltage for driving are applied to the internal electrode layer. Therefore, there was a problem in that only displacement and vibration in the stacking direction due to longitudinal effect displacement could be obtained. That is, a laminated thermistor element in which multiple thermistor layers and internal electrode layers are alternately laminated, the thermistor layers are polarized in the lamination direction, and displacement and vibration in a direction perpendicular to the lamination direction are obtained due to the thickness shear effect. When manufacturing the above! l! ! Since it is not possible to use all the methods, it must be manufactured by bonding multiple thin plates of thermistors that have been previously polarized in the thickness direction with electrodes coated on the plane parallel to the polarization direction using adhesive. There wasn't. The present invention has been made against the background of the above circumstances, and its object is to provide a structure in which a plurality of thermistor layers and internal electrode layers are alternately laminated, and the thermistor layers have a thickness in a direction perpendicular to the lamination direction. It is an object of the present invention to enable the above manufacturing method to be applied to the manufacturing of laminated thermistor elements that undergo sliding displacement or vibration. [Means for Solving the Problems 1] In order to achieve the above object, the present invention provides a structure in which a plurality of thermistor layers and internal electrode layers are alternately laminated, and the thermistor layers have thickness slippage in a direction perpendicular to the lamination direction. A method for manufacturing a laminated thermistor element that is displaced or vibrates, comprising: (a) preparing a thermistor material constituting the thermistor layer; and (b) increasing the electrical resistance at a predetermined temperature or higher lower than the Curie temperature of the thermistor material. (e) a step of preparing a thermistor material with negative temperature characteristics that becomes a conductor by reducing the amount of the thermistor material as a constituent material of the internal electrode layer; (d) a firing step of integrally firing the laminate produced by the lamination step;
) Polarizing the electric field lamix through the internal electrode layer in the stacking direction of the M shoulder body at a temperature higher than 1 degree Celsius and lower than the Curie temperature of the thermistor material, which becomes a conductor of the thermistor material. (f) a polarization step to be carried out;
The method is characterized by comprising an external electrode forming step of forming a driving external electrode on a plane parallel to the polarization direction above the polarization step. It is characterized by Here, as the thermistor material constituting the thermistor layer, a ferroelectric ceramic material such as lead zirconate titanate (PZT) thread or lead titanate (PT) type is used. In addition, as the thermistor material that constitutes the internal electrode layer,
For example, nickel oxide (N io ), fvar oxide (C
oo), spinel-shaped materials mainly composed of manganese oxide (MnO), vanadium oxide (V -0')'i? Sudden change thermistor materials such as , etc. are preferably used. [Operations and Effects 1] That is, the method of the present invention uses a thermistor material with negative temperature characteristics that reduces electrical resistance and becomes a conductor above a predetermined temperature lower than the Curie temperature of the thermistor material as the internal electrode layer; material and thermistor material in a sheet form at a temperature higher than the temperature at which the thermistor material becomes a conductor and lower than the Curie temperature of the thermistor material;
In other words, the polarization process is performed by applying an electric field in the stacking direction of the laminate at a temperature at which the thermistor material becomes a conductor while the piezoelectric ceramic Fuchs material still has ferroelectric properties. In this case, since the thermistor material is a conductor during the polarization process, it acts as a polarization electrode and the thermistor is well polarized in the stacking direction, while the temperature at which the thermistor material becomes a conductor after the polarization process is When the temperature drops to below, the thermistor material begins to function as an insulator, and by applying a driving voltage to the external electrode formed on the plane parallel to the polarization direction, the thickness slip effect causes the thermistor material to function as an insulator. Displacement and vibration in the direction perpendicular to the direction can be obtained. As described above, according to the method of the present invention, a plurality of thermistor layers and internal electrode layers are alternately stacked, the thermistor layers are polarized in the stacking direction, and the external electrodes are formed on a plane parallel to the polarization direction. The laminated thermistor element, which can obtain displacement and vibration in the direction perpendicular to the lamination direction due to the thickness slip effect by applying a voltage to the thermistor layer polarized in the thickness direction of the layer and the internal 74
It can now be manufactured in the same way as when manufacturing a laminated thermistor element, which has displacement and vibration in the lamination direction due to the longitudinal effect in which pole layers are laminated alternately, reducing the number of manufacturing steps and greatly improving productivity. It is. In addition, it is possible to make the thermistor layer thinner, lowering the polarization voltage and reducing the area of the displacement part, and by appropriately selecting the thermistor material and thermistor material, the thermistor layer and internal Various excellent effects can be obtained, such as being able to increase the bonding strength with the electrode layer. [Embodiment 1] Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. First, FIG. 3 is a block diagram illustrating an example of a laminated thermistor element manufactured according to the method of the present invention.
[12. From the internal electrode [14] and the external electrode 30, the thermistor W112 is polarized in the stacking direction, that is, in the vertical direction in the figure. The thermistor layer 12 is made of lead titanate norconate ceramics having ferroelectric properties, while the internal electrode 114 is formed at a predetermined Curie temperature lower than the Curie temperature of the lead titanate zirconate ceramics. The external electrode 30 is made of a vanadium oxide-based rapidly changing thermistor material ceramic, which rapidly decreases its electrical resistance and becomes a conductor at a temperature higher than , and the external electrode 30 is made of a metal material such as nickel. Note that the arrow shown on the thermistor layer 12 in the figure represents the polarization direction. It represents the direction. Next, a method for manufacturing such a laminated thermistor element 10 will be explained. First, the above-mentioned thermistor/[12 is a lead zirconate titanate ceramic material;
Jl? Ceramic materials are prepared and formed into sheets of a predetermined thickness using the doctor blade method, layered alternately, and then heat-pressed. , cut into a predetermined size and shape, and integrally fired. As a result, as shown in FIG.
is obtained, but at this stage, the direction of spontaneous polarization of the thermistor layer 12 is random, and the inside pole 7/114 is an insulator. The lead titanate norconate ceramic material that constitutes the thermistor layer 12 corresponds to the thermistor material, and the vananium oxide ceramic material that constitutes the internal electrode M14 has a Curie temperature lower than that of the piezoelectric ceramic nx material. It corresponds to a rapidly changing thermistor material with negative temperature characteristics whose electrical resistance rapidly decreases above a predetermined temperature and becomes a conductor. Next, as shown in FIG. 2, in the stacking direction of the laminate 16, in an oil bath 22 filled with insulating oil 20 such as silicone oil, 05 bud height 9JI drops and Apply the voltage in the spring of 1AL. The temperature of the insulating oil 20 is set to be higher than the temperature at which the internal electrode layer 14 becomes a conductor and lower than the Curie temperature of the thermistor layer 12, for example, about 70°C.
The internal electrode N14 becomes a conductor, whereas the thermistor layer 1
2 still has ferroelectric properties. For this reason, internal 1! Extreme W1
By applying a voltage across the stack 14, an electric layer is applied to the stack 16 in the stack direction, and the thermistor N12 is polarized well in the stack direction. A pair of external electrodes 3 are provided on the layered body 16 on a plane parallel to the polarization direction.
The laminated thermistor element 10 is obtained by forming 0 with, for example, nickel by an electroless plating method. The normal operating temperature of the laminated thermistor element 10 is sufficiently lower than the temperature at which the internal electrode layer 14 becomes conductive, and the internal electrode layer 14 becomes an insulator and functions only as an adhesive layer for the thermistor 412. For example, the piezoelectric actuator shown in FIG. 4 has a driving power source 26 directly connected between the divided external electrodes 30, and by applying a bias electric field in the stacking direction, the piezoelectric actuator is displacement in the vertical direction occurs. In addition, the piezoelectric actuator shown in Fig. Used in sonic motors, etc. As described above, in this embodiment, the thermistor element 10 is manufactured by alternately laminating the ceramic material constituting the thermistor layer 12 and the ceramic material constituting the internal electrode layer 14, firing them together, and then subjecting them to polarization treatment. , compared to manufacturing by bonding multiple thin plates of thermistors that have been polarized in the thickness direction with electrodes applied on the plane parallel to the polarization direction using adhesive. This reduces the number of manufacturing steps and greatly improves productivity. Furthermore, by adopting such a manufacturing method, it is possible to reduce the thickness of the thermistor layer 12 compared to conventional products, and it is possible to lower the polarization voltage and reduce the area of the displaced portion. . As a result, when the piezoelectric actuator shown in FIG. 4 is used, for example, in a multi-nozzle of a drop-on-demand type piezoelectric inkjet printer head, the resolution can be greatly improved. Furthermore, when the piezoelectric seven cutuator shown in FIG. 5 is used in an ultrasonic motor, it is possible to miniaturize the ultrasonic motor. Furthermore, the multilayer thermistor element 10 of this embodiment has the thermistor layer 12 and internal electrodes/! 14 is obtained by integrally sintering, the bonding strength is high, and there is less deterioration in bonding strength compared to conventional products that are bonded with adhesive, and the advantage is that excellent durability can be obtained. be. In addition, the above-mentioned worms are an example of the present invention, and for example, the thermistor material or thermistor material may be changed as appropriate, or a binder etc. may be added to such materials as necessary. , the present invention may be modified in various ways based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram showing an integrally sintered laminate manufactured in the manufacturing process according to the method of the present invention. FIG. 2 is a diagram illustrating a process of polarizing the thermistor layer of the laminate shown in FIG. 1. FIG. Figure 3 shows IiI! of the laminated thermistor element manufactured through the steps shown in Figures 1 and 2. This is a diagram. 4 and 5 are diagrams each showing an example of a piezoelectric actuator using the laminated thermistor element of FIG. 3. FIG. DESCRIPTION OF SYMBOLS 10... Laminated thermistor element, 12... Thermistor layer, 14... Internal electrode layer, 30... External electrode. very.

Claims (1)

[Claims] A method for manufacturing a laminated piezoelectric ceramic element in which a plurality of piezoelectric ceramic layers and internal electrode layers are alternately laminated, and the piezoelectric ceramic layers undergo thickness sliding displacement or vibration in a direction perpendicular to the lamination direction. a step of preparing a piezoelectric ceramic material constituting the piezoelectric ceramic layer; and a thermistor material with negative temperature characteristics that decreases electrical resistance and becomes a conductor above a predetermined temperature lower than the Curie temperature of the piezoelectric ceramic material. a step of preparing the piezoelectric ceramic material and the thermistor material as a constituent material of the internal electrode layer; a laminating step of forming the piezoelectric ceramic material and the thermistor material into a sheet shape and laminating them alternately; and integrally firing the laminate produced by the laminating step. an electric field is applied in the stacking direction of the laminate at a temperature higher than the temperature at which the thermistor material becomes a conductor and lower than the Curie temperature of the piezoelectric ceramic material, and the laminate is fired in the firing step. Manufacturing a laminated piezoelectric ceramic element comprising: a polarization step of subjecting piezoelectric ceramics to polarization treatment; and an external electrode forming step of forming driving external electrodes on a plane parallel to the polarization direction resulting from the polarization step. Method.