JP2006052107A - Piezoelectric ceramic, production method therefor, and piezoelectric actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide piezoelectric ceramics having both a high piezoelectric strain constant and a high Curie temperature and exhibiting a desired displacement amount even at a high temperature, a production method therefor and a piezoelectric actuator. <P>SOLUTION: The piezoelectric ceramics 11a, 11b, 12a, 12b, 13a and 13b are obtained by separately calcining powder of first material expressed by chemical compositional formula: Pb<SB>0.985</SB>Bi<SB>0.01</SB>(Zn<SB>1/12</SB>Ni<SB>3/12</SB>Nb<SB>2/3</SB>)<SB>0.5</SB>Ti<SB>0.32</SB>Zr<SB>0.18</SB>O<SB>3</SB>and powder of second material expressed by chemical compositional formula: Pb<SB>0.97</SB>Bi<SB>0.02</SB>(Zn<SB>1/3</SB>Nb<SB>2/3</SB>)<SB>0.15</SB>Ti<SB>0.42</SB>Zr<SB>0.43</SB>O<SB>3</SB>, then mixing the calcined powder, and firing the resulting mixture. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a piezoelectric ceramic having a property in which crystals are distorted by the action of an applied voltage, a manufacturing method thereof, and a piezoelectric actuator using the piezoelectric ceramic, and in particular, obtains a desired large displacement even when used under high temperature conditions. The present invention relates to a piezoelectric ceramic, a method of manufacturing the same, and a piezoelectric actuator.

2. Description of the Related Art Conventionally, piezoelectric actuators using the reverse piezoelectric effect are known as products using piezoelectric ceramics. When a large displacement is required in a piezoelectric actuator, a piezoelectric ceramic having a large piezoelectric strain constant as shown in Patent Document 1 is suitable as the piezoelectric ceramic to be used, and operation under a high temperature condition is required. For this, a material having a high Curie temperature as shown in Patent Document 2 is required.
Japanese Patent Publication No. 60-57237 Japanese Patent Laid-Open No. 10-287469

  Generally, as the piezoelectric strain constant increases, the Curie temperature tends to decrease. Therefore, if piezoelectric ceramics with a high Curie temperature are used for high temperature use, a large displacement cannot be obtained when configured as an actuator. End up.

  Currently, the range of use of piezoelectric actuators has been expanded, and for example, use under high-temperature conditions such as being incorporated in in-vehicle devices is increasing. Therefore, a piezoelectric ceramic having a large piezoelectric strain constant and a high Curie temperature is desired.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a piezoelectric ceramic that can obtain a desired amount of displacement even under high temperature conditions, a manufacturing method thereof, and a piezoelectric actuator.

The piezoelectric ceramic of the present invention includes a first material represented by a chemical composition formula Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ and a chemical composition formula Pb _0.97. It is characterized by being obtained by mixing with a second material represented by Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ .

In addition, the piezoelectric actuator of the present invention includes a first material represented by a chemical composition formula Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ , and a chemical composition formula A piezoelectric ceramic obtained by mixing a second material represented by Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ and an electrode formed on the piezoelectric ceramic. It is characterized by providing.

  The first material has a large piezoelectric strain constant but has a low Curie temperature and a small amount of displacement when used at a high temperature. The second material has a large Curie temperature but a small piezoelectric strain constant and is necessary for a desired application. Although the amount of displacement cannot be obtained, in piezoelectric ceramics obtained by mixing these two materials, either the piezoelectric strain constant or the Curie temperature is not extremely small, and both are values that are practically satisfactory. Indicates. Thereby, the deterioration (drop) of the displacement amount accompanying a temperature rise can be suppressed, and a desired displacement amount can be obtained even under high temperature conditions.

  Depending on the mixing ratio of the first material and the second material, a very large amount of displacement can be obtained, but the deterioration rate at a high temperature becomes relatively large, or the deterioration rate at a high temperature should be kept very small. However, since the characteristic balance between the two is deteriorated such that the displacement amount is not so large, the mixing ratio at which both the displacement amount and the deterioration rate at high temperature can be satisfied is the first. It is preferable that the mixing ratio of the material is 25 wt% or more and 50 wt% or less, and conversely the mixing ratio of the second material is 50 wt% or more and 75 wt% or less.

In addition, the method for producing a piezoelectric ceramic according to the present invention includes a powder of the first material represented by the chemical composition formula Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O _3. And a powder of the second material represented by the chemical composition formula Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ , and firing the mixed powder And a process.

  The first material has a large piezoelectric strain constant but has a low Curie temperature and a small amount of displacement when used at a high temperature. The second material has a large Curie temperature but a small piezoelectric strain constant and is necessary for a desired application. Although the amount of displacement cannot be obtained, in piezoelectric ceramics obtained by mixing these two materials, either the piezoelectric strain constant or the Curie temperature is not extremely small, and both are values that are practically satisfactory. Indicates. Thereby, the deterioration (drop) of the displacement amount accompanying a temperature rise can be suppressed, and a desired displacement amount can be obtained even under high temperature conditions.

  In particular, if the powder of the first material and the powder of the second material are calcined separately and then mixed and fired, the sinterability can be reduced by reducing voids and unstable components. It can be improved.

In addition, the method for producing the piezoelectric ceramic according to the present invention is a method of calcining a material powder represented by the chemical composition formula Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ . After that, the step of mixing, drying and crushing in order is repeated at least twice before firing.

  By repeating the process consisting of the above (mixing, drying, pulverization) at least twice after calcining, the sintered body can be made a denser sintered body having a smaller particle size and a higher density. The density and the piezoelectric strain constant correlate with each other, and the piezoelectric strain constant increases as the density increases. In piezoelectric ceramics, the larger the piezoelectric strain constant, the larger the displacement when a voltage is applied.

Also, the piezoelectric ceramic manufacturing method of the present invention is obtained by mixing and calcining the material powder represented by the chemical composition formula Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O _3. It is characterized in that baking is performed after repeating the steps of drying and pulverization in order at least twice.

  By repeating the process consisting of the above (mixing, drying, pulverization) at least twice after calcining, the sintered body can be made a denser sintered body having a smaller particle size and a higher density. The density and the piezoelectric strain constant correlate with each other, and the piezoelectric strain constant increases as the density increases. In piezoelectric ceramics, the larger the piezoelectric strain constant, the larger the displacement when a voltage is applied.

  The piezoelectric ceramic of the present invention shows a high value with a good balance in both the piezoelectric strain constant and the Curie temperature, a large displacement can be obtained even at a high temperature, and further, the deterioration of the displacement due to the temperature rise can be suppressed. As a result, reliability under high temperature conditions can be improved.

  According to the method for manufacturing a piezoelectric ceramic of the present invention, it is possible to manufacture a piezoelectric ceramic in which both the piezoelectric strain constant and the Curie temperature exhibit high values in a balanced manner. As a result, the obtained piezoelectric ceramic can obtain a large displacement even at a high temperature, and further, the deterioration of the displacement amount accompanying the temperature rise is suppressed, and the reliability under a high temperature condition is high.

  The piezoelectric actuator of the present invention uses piezoelectric ceramics that show high values in a balanced manner both in terms of the piezoelectric strain constant and the Curie temperature. Can do. As a result, reliability under high temperature conditions can be improved.

[Piezoelectric ceramics]
The piezoelectric ceramic according to the embodiment of the present invention includes a first material represented by a chemical composition formula Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ , It can be obtained by mixing a second material represented by the composition formula Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ at an arbitrary mixing ratio. That is, the composition of each component element of the piezoelectric ceramics obtained in the present _{embodiment, Pb a Bi b Zn c Ni} d Nb e Ti f Zr g O 3 (0.970 ≦ a ≦ 0.985 0.01 ≦ b ≦ 0.02 0.040 ≦ c ≦ 0.049 0 <d ≦ 0.125 0.099 ≦ e ≦ 0.200 0.380 ≦ f ≦ 0.420 0.180 ≦ g ≦ 0.430).

  A method for manufacturing the piezoelectric ceramic will be described with reference to the flowchart of FIG. The first material and the second material are processed separately (without being mixed with each other) until step S9.

(Step S1a)
High-purity PbO, ZrO ₂ , TiO ₂ , Bi ₂ O ₃ , Nb ₂ O ₅ , ZnO, and NiO are used as the raw material powder, and these are used as the first material composition Pb _0.985 Bi _0.01 (Zn _1/12 Ni _{3 / 12} Nb _2/3 ) Weigh so that _0.5 Ti _0.32 Zr _0.18 O ₃ .

(Step S2a)
The powder is put into a ball mill and pure water is added to perform wet mixing for 20 hours.

(Steps S3a to S5a)
The powder after wet mixing is dried and ground, and then calcined at 850 ° C. for 3 hours.

(Steps S6a to S8a)
The calcined powder is again put in a ball mill and wet mixed, and then dried and pulverized. Various conditions of mixing, drying, and pulverization are the same as the conditions of mixing, drying, and pulverization in the above steps S2a to S4a.

Steps S1b to S8b are performed for the second material as well as the first material. That is, first, high-purity PbO, ZrO ₂ , TiO ₂ , Bi ₂ O ₃ , Nb ₂ O ₅ , and ZnO are used as raw material powders, and these are used as the second material composition Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ is weighed (step S1b).

(Step S2b)
The powder is put into a ball mill and pure water is added to perform wet mixing for 20 hours.

(Steps S3b to S5b)
The powder after wet mixing is dried and ground, and then calcined at 850 ° C. for 3 hours.

(Steps S6b to S8b)
The calcined powder is again put in a ball mill and wet mixed, and then dried and pulverized. Various conditions of mixing, drying, and pulverization are the same as the conditions of mixing, drying, and pulverization in the above steps S2b to S4b.

(Step S9)
The powder of the first material that has finished the process up to step S8a and the powder of the second material that has finished the process up to step S8b are mixed at a desired mixing ratio, for example, the first material is 25% by weight. The second material is 75% by weight, the first material is 50% by weight, the second material is 50% by weight, the first material is 75% by weight, the second material is 25% by weight, etc. Weigh so that the mixing ratio is achieved, put these powders in a ball mill, add pure water, and perform wet mixing for 10 hours.

(Steps S10 to S12)
After the wet-mixed powder is dried and pulverized, an organic binder (for example, polyvinyl alcohol) is added and granulated.

(Steps S13 to S14)
The powder after the granulation step is press-molded at a pressure of 8 kg / cm ² to obtain a square shaped body. And this molded object was sealed in the container which consists of MgO etc., and it baked for 5 hours by oxygen atmosphere and the temperature of 1250-1300 degreeC.

  By this firing, unstable components such as binders are decomposed and removed, and the reaction between each component element proceeds to produce a stable compound. At the same time, it is shrunk and densified by sintering, and has a certain shape and strength. The body is obtained.

  Then, this sintered body is cut into a plate having a thickness of 1.0 mm using an inner peripheral blade (a cutting means in which diamond abrasive grains are formed on the inner peripheral side of the donut-shaped disk), and electrolytic plating is performed on both sides thereof. A Ni layer was formed. A circular plate having a diameter of 18 mm was punched out from this plate using an ultrasonic processing machine, and subjected to polarization treatment by applying a DC voltage of 1.5 kV / cm in silicon oil at 80 ° C. for 30 minutes. Then, the piezoelectric strain constant d31 of the disk was measured by a resonance-antiresonance method using an impedance analyzer, and the temperature at which the relative dielectric constant reached a maximum value was determined as the Curie temperature Tc from the temperature characteristics of the relative dielectric constant. . The density was also measured. The results are shown in Table 1.

  In Table 1, Example 2 shows the case where the mixing ratio of the first material: second material = 75% by weight: 25% by weight, and Example 3 shows the first material: second material = 50. Example 4 shows a case where the mixing ratio was 50% by weight, and Example 4 shows a case where the mixing ratio of first material: second material = 25% by weight: 75% by weight.

The chemical composition formula of the piezoelectric ceramic of Example 1 is Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ , that is, the same as that of the first material. This is because wet mixing is performed only with the powder of the first material without mixing the powder of the second material in the above step S9, and thereafter, the firing of step S14 is performed using only the powder of the first material. Obtained. Therefore, the piezoelectric ceramic of Example 1 was manufactured by steps S1a, S2a, S3a, S4a, S5a, S6a, S7a, S8a, S9, S10, S11, S12, S13, and S14 in FIG.

The chemical composition formula of the piezoelectric ceramic of Example 5 is Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ , that is, the same as that of the second material. This is because wet mixing is performed only with the powder of the second material without mixing the powder of the first material in step S9, and thereafter, the firing of step S14 is performed using only the powder of the second material. Obtained. Therefore, the piezoelectric ceramic of Example 5 was manufactured through the steps S1b, S2b, S3b, S4b, S5b, S6b, S7b, S8b, S9, S10, S11, S12, S13, and S14 in FIG.

  As can be seen from the results in Table 1, Example 1 using only the first material has a larger piezoelectric strain constant d31 but lower Curie temperature Tc than the other examples, and Example using only the second material. 5 has a higher Curie temperature Tc than the other examples, but a smaller piezoelectric strain constant d31. On the other hand, in Examples 2 to 4 obtained by mixing and firing the first material and the second material, the piezoelectric strain constant d31 and the Curie temperature Tc are relatively high. The balance between the two is good. Therefore, a large displacement (amplitude) can be obtained even when used as a material for a piezoelectric actuator used under high temperature conditions.

  Next, Table 2 shows the result of the same measurement as in Table 1 for the piezoelectric ceramic obtained by the manufacturing method shown in FIG.

  Each of the piezoelectric ceramics of Examples 6 to 8 is manufactured as follows. First, the raw material powder of the first material and the raw material powder of the second material are mixed in a desired mixing ratio, for example, the first material is 75% by weight and the second material is 25% by weight (Example 6). ), 50% by weight of the first material and 50% by weight of the second material (Example 7), and 25% of the first material and 75% by weight of the second material (Example 8). ) (Step S101), put these powders in a ball mill, add pure water, and perform wet mixing for 20 hours (step S102).

  The powder after wet mixing is dried (step S103), pulverized (step S104), and calcined at 850 ° C. for 3 hours (step S105).

  The calcined powder is again put into a ball mill and wet-mixed (step S106), and then dried (step S107) and pulverized (step S108). The various conditions of mixing, drying, and pulverization are the same as the mixing, drying, and pulverizing conditions in steps S102 to S104.

Then, an organic binder (for example, polyvinyl alcohol) is added and granulated (step S109), and press-molded (step S110) with a pressure of 8 kg / cm ² to obtain a square molded body. Then, this molded body was sealed in a container made of MgO or the like, and fired for 5 hours in an oxygen atmosphere at a temperature of 1250 to 1300 ° C. (step S111).

The chemical composition formula of the piezoelectric ceramic of Comparative Example 1 is Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ , that is, the same as that of the first material. This is because wet mixing is performed only with the powder of the first material without mixing the powder of the second material in step S102, and thereafter, the firing of step S111 is performed using only the powder of the first material. Obtained. Comparative Example 1 corresponds to the piezoelectric ceramic disclosed in Patent Document 1.

The chemical composition formula of the piezoelectric ceramic of Comparative Example 2 is Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ , that is, the same as that of the second material. This is because wet mixing is performed only with the powder of the second material without mixing the powder of the first material in step S102, and thereafter, the firing of step S111 is performed using only the powder of the second material. Obtained. Comparative Example 2 corresponds to the piezoelectric ceramic disclosed in Patent Document 2.

  Table 1 and Table 2 differ only in the manufacturing method of piezoelectric ceramics, and the measurement method and measurement conditions are the same. When the same mixing ratio is compared between Table 1 and Table 2, the density and piezoelectric strain constant d31 obtained by the manufacturing method shown in FIG. 1 are higher than those obtained by the manufacturing method shown in FIG. Is getting bigger. This is because, in the manufacturing method of FIG. 1, the powders of two kinds of materials are separately calcined and then mixed and fired to reduce vacancies and unstable components, thereby improving the sinterability. Furthermore, compared with the manufacturing method of FIG. 2, since the process consisting of (mixing-drying-pulverizing) is performed once after calcination, the sintered body has a smaller particle size and a higher density. Is considered to have been obtained. The density and the piezoelectric strain constant d31 are correlated with each other, and the piezoelectric strain constant d31 increases as the density increases. In piezoelectric ceramics, the larger the piezoelectric strain constant d31, the larger the displacement when a voltage is applied.

  In the manufacturing method of FIG. 1, the process consisting of (mixing-drying-pulverizing) performed between calcining and granulation is not limited to being repeated twice, but may be performed three or more times. As the pulverization progresses, the number of pulverized particles increases, and the force for pulverization is dispersed due to the adhesion and agglomeration phenomenon peculiar to the powder. As a result, the pulverized product itself functions as a cushion. Will not become finer. Therefore, in order to shorten the production time, it is preferable that the process consisting of (mixing, drying, pulverization) performed between calcining and granulation is repeated twice.

  In summary, the manufacturing method shown in FIG. 1 can increase the piezoelectric strain constant d31 of the obtained piezoelectric ceramic than the manufacturing method shown in FIG. Furthermore, the piezoelectric ceramic obtained by mixing both the piezoelectric ceramics made of only the first material or only the second material has a better balance between the piezoelectric strain constant d31 and the Curie temperature Tc. In particular, if the above-mentioned combination, that is, a mixture of the first material and the second material is manufactured by the method shown in FIG. 1, the above-mentioned performance is further improved and a piezoelectric ceramic capable of obtaining a large displacement even under high temperature conditions is obtained. Obtainable.

[Piezoelectric actuator]
When a piezoelectric actuator is manufactured using the piezoelectric ceramic according to the present embodiment as described above, a large amplitude can be obtained even under high temperature use conditions, and further, the piezoelectric actuator can be reduced in amplitude deterioration and excellent in heat resistance.

  FIG. 3 shows a multimorph piezoelectric actuator 1 as an example of the piezoelectric actuator. This has a structure in which three piezoelectric ceramics 11a, 12a, 13a, 11b, 12b, and 13b are laminated on both surfaces of the plate-like intermediate electrode 6, respectively. Electrodes are formed on both surfaces of each of the piezoelectric ceramics 11a, 12a, 13a, 11b, 12b, and 13b. When an AC voltage is applied to the electrodes and the intermediate electrode 6 from the power supply 8, the electrodes are narrowed by a pair of jigs 7a and 7b. It swings in the direction of arrow X with the pressed portion as a fulcrum.

  Each of the piezoelectric ceramics 11a, 12a, 13a, 11b, 12b, and 13b has a length of 35.0 mm, a width of 3.0 mm, and a thickness from a single plate (thickness 0.1 mm) having Ni plating (this functions as an electrode) on both surfaces described above. A 0.1 mm long strip was cut out and applied with a direct current voltage of 1.55 kV / cm for 30 minutes in silicon oil at 80 ° C. for polarization treatment (the polarization direction is indicated by an arrow on each piezoelectric ceramic).

  The intermediate electrode 6 is formed by bonding two shim materials (elastic reinforcing plates) having a length of 40.0 mm, a width of 3.0 mm, and a thickness of 0.12 mm. The shim material is made of, for example, CFRP (Carbon Fiber Reinforced Plastic). The piezoelectric ceramics 11a, 12a, 13a, 11b, 12b, 13b, and the piezoelectric ceramics 11a, 11b and the intermediate electrode 6 are bonded together with an epoxy resin.

  The total thickness of each of the piezoelectric ceramics 11a, 12a, 13a, 11b, 12b, 13b and the intermediate electrode 6 is 0.84 mm. The length from the portion narrowed by the jigs 7a and 7b to the tip is 20 mm. The thickness of the jigs 7a and 7b is 5 mm.

  Table 3 shows the results of measuring the amplitude of the piezoelectric actuator 1 and its deterioration rate. In Table 3, Examples 1 to 5 correspond to Examples 1 to 5 in Table 1, and Example 7 corresponds to Example 7 in Table 2.

  The amplitude was measured with a laser displacement meter using the amount of expansion and contraction in the longitudinal direction of the piezoelectric actuator 1 when a sine wave having a frequency of 10 Hz and an AC voltage of 40 Vp-p was applied from the power supply 8 as the amplitude.

  The amplitude deterioration rate was measured by the following method. First, a sine wave having a frequency of 10 Hz and an AC voltage of 40 Vp-p was applied to the piezoelectric actuator 1 to measure the initial amplitude. Next, the piezoelectric actuator 1 whose initial amplitude was measured was placed in a constant temperature bath at 85 ° C., and a sine wave having a frequency of 10 Hz and an AC voltage of 40 Vp-p was applied and vibrated 1 million times. Next, the piezoelectric actuator 1 after 1 million vibrations was cooled to room temperature, and then a sine wave having a frequency of 10 Hz and an AC voltage of 40 Vp-p was applied to measure the amplitude. The percentage by which the amplitude amount dropped from the initial amplitude amount was determined as the amplitude deterioration rate.

  From the results of Table 3, Example 3 was set with the first material: second material = 50 wt%: 50 wt%, and the first material: second material = 25 wt%: 75 wt% In Example 4, the amplitude amount desired to be obtained in practice is satisfied, and the amplitude deterioration rate is as small as about 7%. Therefore, it is preferable to use the piezoelectric ceramics of Example 3 or Example 4 for applications where it is desired to obtain a large displacement that is stable under high temperature conditions. In addition, the mixing ratio between Example 3 and Example 4, for example, 1st material: 2nd material = 30 weight%: 70 weight%, 1st material: 2nd material = 40 weight%: 60 Even when the weight percentage is set, the same effects as those of the third and fourth embodiments can be obtained. That is, the mixing ratio of the first material to the second material is 25 wt% or more and 50 wt% or less. Conversely, the mixing ratio of the second material to the first material is 50 wt% or more and 78 wt%. A piezoelectric actuator that can swing stably and well even at high temperatures can be realized with the following.

[Application example of piezoelectric actuator]
FIG. 4 and FIG. 5, which is an enlarged cross-sectional view in the [A]-[A] line direction, show an application example of the piezoelectric actuator according to the present embodiment.

  As shown in FIG. 4, the long plate-like piezoelectric actuators 21 a to 21 d are attached to the four corner positions of the frame 23 around the display screen 22. Each of the piezoelectric actuators 21a to 21d is, for example, a multimorph type piezoelectric actuator, but is not limited thereto, and may be a monomorph type, a unimorph type, a bimorph type, or the like.

  A touch panel 24 made of a transparent film is attached on the frame 23 via a support member 25 as shown in FIG. A gap is secured between the touch panel 24 and the frame 23 by the support member 25, and piezoelectric actuators 21a to 21d are arranged in the gap.

  A first support portion 26 a is provided between one end portion of the piezoelectric actuator 21 a and the frame 23, and a second support portion 26 b is provided between the other end portion and the frame 23. Further, a third support portion 26c is provided between the intermediate portion of the piezoelectric actuator 21a and the back surface of the touch panel 24. Similarly, the piezoelectric actuator 21b is provided with a first support portion 27a between one end thereof and the frame 23, and with a second support portion 27b provided between the other end portion and the frame 23. Between the touch panel 24 and the back surface of the touch panel 24, a third support portion 27c is provided. The same applies to the other piezoelectric actuators 21c and 21d. Thus, the piezoelectric actuators 21 a to 21 d are supported at three points by the first, second, and third support portions between the touch panel 24 and the frame 23.

  When the user touches and operates the touch panel 24 with a finger or a stylus pen, the operation signal is supplied to the piezoelectric actuators 21a to 21d via the signal line 28, and the piezoelectric actuators 21a to 21d vibrate. This vibration is transmitted to the touch panel 24 via the third support portions 26c and 27c, and the touch panel 24 vibrates. Thereby, the user can feel the vibration of the touch panel 24 directly with his / her finger or via the stylus pen. That is, the input operation feeling of the touch panel 24 can be obtained by touch.

  Other application examples of the piezoelectric actuator include a camera shutter, a VTR (Video Tape Recorder) head tracking adjustment mechanism, and a piezoelectric fan.

  As mentioned above, although embodiment of this invention was described, of course, this invention is not limited to this, A various deformation | transformation is possible based on the technical idea of this invention.

  The various conditions such as temperature and time in each process for manufacturing the piezoelectric ceramics described above are examples, and are not limited thereto. In the mixing step, a ball mill (container-driven mill) is used, but other than this, a medium stirring mill, a composite mill, a centrifugal fluid mill, or the like may be used.

It is a manufacturing process flowchart of the piezoelectric ceramic of Example 1- Example 5. FIG. It is a manufacturing process flowchart of the piezoelectric ceramics of Example 6-8. It is a structural diagram showing an example of a piezoelectric actuator according to an embodiment of the present invention. It is a top view which shows the application example of the piezoelectric actuator which concerns on embodiment of this invention. It is an expanded sectional view of the [A]-[A] line direction in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Piezoelectric actuator, 6 ... Intermediate electrode, 11a, 11b, 12a, 12b, 13a, 13b ... Piezoelectric ceramics, 21a-21d ... Piezoelectric actuator, 24 ... Touch panel.

Claims (8)

A first material represented by a chemical composition formula Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ ;
A second material represented by the chemical composition formula Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ ;
Piezoelectric ceramics obtained by mixing The mixing ratio of the first material is 25% by weight or more and 50% by weight or less,
2. The piezoelectric ceramic according to claim 1, wherein a mixing ratio of the second material is 50 wt% or more and 75 wt% or less. The powder of the first material represented by the chemical composition formula Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ and the chemical composition formula Pb _0.97 Bi _0.02 (Zn _{1 / 3} Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ is mixed with the powder of the second material represented by;
Firing the mixed powder;
A method for producing a piezoelectric ceramic, comprising: The method for manufacturing a piezoelectric ceramic according to claim 3, wherein the powder of the first material and the powder of the second material are calcined separately and then mixed and fired. A method for producing a piezoelectric ceramic comprising a material represented by the chemical composition formula Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ ,
After calcining the powder of the material, firing is performed after repeating the steps of mixing, drying, and pulverizing at least twice. A method for producing a piezoelectric ceramic comprising a material represented by the chemical composition formula Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ ,
After calcining the powder of the material, firing is performed after repeating the steps of mixing, drying, and pulverizing at least twice. The first material represented by the chemical composition formula Pb _0.985 Bi _0.01 (Zn _1/12 Ni _3/12 Nb _2/3 ) _0.5 Ti _0.32 Zr _0.18 O ₃ and the chemical composition formula Pb _0.97 Bi _0.02 (Zn _1/3 Nb _2/3 ) _0.15 Ti _0.42 Zr _0.43 O ₃ and a piezoelectric ceramic obtained by mixing with a second material represented by:
An electrode formed on the piezoelectric ceramic;
A piezoelectric actuator comprising: The mixing ratio of the first material is 25% by weight or more and 50% by weight or less,
The piezoelectric actuator according to claim 7, wherein a mixing ratio of the second material is 50 wt% or more and 75 wt% or less.

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