JPH0786861A - Piezoelectric vibrator and its production - Google Patents

Abstract

PURPOSE:To produce a piezoelectric vibrator that has high stability. CONSTITUTION:A conductive projecting part 26 is formed on the surface of a piezoelectric substrate 1 where a driving electrode 2 is provided or on the surface of the electrode 2 and at a position near the node point of the substrate 1 which contains the electrodes 2 on its both surfaces opposite to each other. In such a constitution of a piezoelectric vibrator, the ultrafine particles are sprayed to the substrate 1 through a nozzle 15 having an inner diameter smaller than the width of the part 26. Thus the part 26 is formed at a prescribed point with high accuracy. Furthermore an even sectional shape is secured for the part 26 with rather an acuta angle formed at its tip owing to the conductive material of the part 26. Thus a stable contact is secured to an external electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrator using a piezoelectric material such as piezoelectric ceramic, crystal, niobium lithium, and the like, and a piezoelectric vibrator having a conductive protrusion portion that is held and connected to an external electrode. The present invention relates to a manufacturing method thereof.

[0002]

2. Description of the Related Art An example of a piezoelectric vibrator using a piezoelectric material such as piezoelectric ceramic, crystal, niobium lithium, and the like will be described below with reference to FIGS. Piezoelectric vibrators used for mechanical filters and oscillators
It is made of a material such as piezoelectric ceramic, quartz, niobium lithium, and the like, and a suitable vibration mode is excited by the piezoelectric effect depending on the frequency range used. Then, these piezoelectric vibrators are held in the vicinity of the node where the vibration amplitude becomes 0 so as not to suppress the vibration of the vibrator, and are electrically connected, and are configured as a filter, an oscillator, or the like. Since these nodes are points or lines having no area, it is ideally desirable to hold the piezoelectric vibrator by points or lines in terms of characteristics. However, in actuality, in order to realize stable holding of the piezoelectric vibrator, the piezoelectric vibrator is held in a dot shape or a linear shape with a certain finite area.

FIG. 5 is a perspective view of a rectangular plate type piezoelectric vibrator made of a piezoelectric material such as piezoelectric ceramic. Piezoelectric substrate 1
Drive electrodes 2 and 2 are formed on two opposing surfaces of
When an electric field is applied between the electrodes 2 and 2, longitudinal vibration is excited in the longitudinal direction of the rectangular plate. The nodes of vibration in the length vibration mode are linear in the center of the rectangle. Therefore, as shown in the figure, the surface of the driving electrodes 2 and 2 or the surface of the piezoelectric substrate 1 on which the driving electrodes 2 and 2 are provided in the vicinity of the node points of the piezoelectric substrate 1 is sprayed with a conductive material. The protrusions 3 and 3 are formed.

FIG. 6 schematically shows a holding structure for a vibrator. The piezoelectric vibrator shown in FIG. 5 is sandwiched and held between the external electrodes 4 and 4 provided inside the outer containers 5 and 5 via the protrusions 3 and 3. Furthermore, the external electrodes 4, 4
Are connected to external terminals 6 and 6, respectively. FIG. 7 is a schematic cross-sectional view of the vicinity of the protrusion 3 formed by, for example, the thermal spraying method. The base end surface of the protruding portion 3 is attached to and in contact with the driving electrode 2 provided on the piezoelectric substrate 1, and the tip end surface is in contact with the fine irregularities 7 on the surface of the outer electrode 4, which are pushed into the external electrode 4 by external pressure. There is. As a result, the protrusion 3 is prevented from being displaced from the external electrode 4 and the holding stability is improved.

[0005]

However, although it is possible to form the protrusion 3 having the basic function by the above-mentioned thermal spraying method or the like, the following problems have occurred. First of all, the protrusions 3 basically need to be formed in the vicinity of the node points of the piezoelectric vibrator in a linear or dot shape. At this time, if they are formed by a thermal spraying method or another film forming method, A pattern forming means such as a mask method or a printing method is required to form the lines or points. However,
It is difficult to always form a projection having a stable shape from the viewpoint of the durability of the forming means, and therefore, there is a problem that the holding of the piezoelectric vibrator becomes unstable and the characteristics are not stable. .

Secondly, as shown in FIG. 7, the shape of the projection 3 formed by the above-mentioned means, when formed by, for example, a thermal spraying method, its surface condition is fine due to the nature of the sprayed film quality. Visually, the surface state is such that many fine irregularities 7 of several μm to several tens of μm are formed. As a result, the unevenness 7 is pressed into the external electrode 4 by external pressure and comes into contact with the external electrode 4 to prevent the protrusions 3 and 3 from being displaced from the external electrodes 4 and 4. However, the shape of the unevenness 7 formed by the thermal spraying method is difficult to control, and therefore, the holding state is changed due to a slight change in the external pressure condition and the like, and it is difficult to obtain stable support.

Therefore, an object of the present invention is to solve the above problems and to provide a piezoelectric vibrator having high stability and a method for manufacturing the same.

[0008]

According to another aspect of the present invention, there is provided a piezoelectric vibrator, wherein a piezoelectric substrate, driving electrodes provided on two opposing surfaces of the piezoelectric substrate, and the piezoelectric substrate near the node point of the piezoelectric substrate. What is claimed is: 1.A piezoelectric vibrator comprising: a surface on which a driving electrode is provided or a conductive protrusion provided on the surface of a driving electrode; and an external electrode which is brought into contact with and held by the protrusion, wherein the protrusion is made of a conductive material. It is characterized by comprising ultrafine particles of.

According to a second aspect of the invention, there is provided the piezoelectric vibrator according to the first aspect, wherein a plurality of protrusions are provided in a dot shape. According to a third aspect of the present invention, there is provided a method for manufacturing a piezoelectric vibrator, wherein a driving electrode of the piezoelectric substrate is provided on a surface on which the driving electrode is provided or a surface of the driving electrode in the vicinity of a node point of the piezoelectric substrate provided with two driving electrodes facing each other. A method of manufacturing a piezoelectric vibrator for forming a conductive protrusion, characterized in that ultrafine particles of a conductive material are blown from a nozzle having an inner diameter equal to or smaller than the width of the protrusion to form the protrusion.

According to a fourth aspect of the present invention, in the method of manufacturing a piezoelectric vibrator according to the third aspect, a piezoelectric substrate is installed in the protrusion forming chamber, and the conductive material is melted in a vacuum in an evaporation chamber connected to the protrusion forming chamber by a pipe. After being evaporated, it is cooled by a gas to form ultrafine particles, and the ultrafine particles are ejected from a nozzle provided at a tip of a pipe in the projection forming chamber by a pressure difference between the evaporation chamber and the protrusion forming chamber. It is a thing.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a piezoelectric vibrator according to the third aspect, characterized in that the nozzle or the piezoelectric substrate is scanned in a predetermined movement pattern to form the protrusion in a linear or dot shape. is there.

[0012]

According to the structure of the present invention, since the protrusions are formed of ultrafine particles of a conductive material, the cross-sectional shape of the protrusions can be made to have a uniform shape with a slightly sharp tip, and the protrusions can be brought into contact with external electrodes. Is stable. Further, by forming the protrusion of the piezoelectric vibrator by spraying ultrafine particles from the nozzle, the protrusion can be accurately formed at a predetermined location.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The components having the same or equivalent functions as those of the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a schematic view of an embodiment showing a method for manufacturing a piezoelectric vibrator of the present invention.

In FIGS. 1 and 2, 1 is an opposing 2
It is a piezoelectric substrate having driving electrodes 2 and 2 provided on one surface thereof, and is installed on the moving device 10 in the projection forming chamber 9. Reference numeral 11 is an evaporation chamber, and the conductive protrusion 2 is provided inside thereof.
A melt evaporation means 13 for a conductive material 12 forming 6 is provided. The evaporation chamber 11 and the projection forming chamber 9 are connected to the pipe 14
And an ultrafine particle transfer control valve 24 is provided in the middle of the pipe 14, and the pipe 1 in the projection forming chamber 9
A nozzle 15 having an inner diameter equal to or smaller than the width of the protrusion 26 provided on the piezoelectric substrate 1 is provided at the tip of the four. Reference numeral 16 is an energy inputting means to the melt evaporation means 13, and is provided with a gas introduction port 17 for cooling the evaporation gas to generate ultrafine particles 25. On the other hand, the projection forming chamber 9 is also provided with a gas introduction port 18 for keeping the inside of the chamber at a predetermined atmospheric pressure. The evaporating chamber 11 and the protrusion forming chamber 9 are controlled by the vacuum pump 2 via valves 19 and 20 so as to have a predetermined pressure.
Connected to 1. Further, 22 and 23 are pressure gauges for monitoring the respective room pressures.

Next, a procedure for forming the protrusion 26 of the piezoelectric vibrator will be described. First, the evaporation chamber 11 is maintained at a predetermined vacuum pressure, and when the conductive material 12, such as NiCr or Mo, which has a relatively high hardness, is heated and melted in the melt evaporation means 13, the material evaporates. At this time, when a gas such as He or Ar is introduced from the gas introduction port 17 to increase the pressure and cool the evaporated molecules, ultrafine particles 25 having a particle size of sub-μm or less are generated. Then, first, the inside of the protrusion forming chamber 9 is kept at a lower pressure side than the inside of the evaporation chamber 11, and after the generation of the ultrafine particles 25 in the evaporation chamber 11,
When the ultrafine particle transfer control valve 24 is opened, the ultrafine particles 25 generated in the evaporation chamber 11 pass through the pipe 14 due to the pressure difference between the evaporation chamber 11 and the projection forming chamber 9 and are ejected at a higher speed than the tip of the nozzle 15. . At this time, the evaporation chamber 11 is about 10 k
The pressure of Pa and the protrusion forming chamber 9 is adjusted to be about several hundred Pa. FIG. 2 shows the details of the nozzle 15 and the piezoelectric substrate 1 in the vicinity where the protrusion 26 is formed. The ultrafine particles 25 are ejected from the nozzle 15 at a high speed and are deposited on the surface of the driving electrode 2 in the vicinity of the node point of the piezoelectric substrate 1, and when the nozzle 15 is fixed at the same position for a predetermined time, the tip is sharply angled. The protrusion 26 is formed. At this time, the piezoelectric substrate 1 is moved to the moving device 1
When 0 is carried in the direction of arrow A, the ultrafine particle carrying control valve 24 is closed during carrying and is released again to form a similar projection 26 '. In this way, the moving device 10
By controlling the ultrafine particle transfer control valve 24, the protrusions 26, 26 'can be formed to have the same shape, and the strength of adhesion of the formed protrusions 26, 26' to the drive electrode 2 surface is It is possible to control the ejection speed and the state of the piezoelectric substrate 1, and it is possible to secure sufficient adhesion strength. Further, the supply amount of the ultrafine particles 25 may be gradually changed in order to secure the sharpness of the projection shape, and the effect is more remarkable because the ultrafine particles 25 are used.

FIG. 3 shows an outline of the piezoelectric vibrator main body 29 formed by such a method. Piezoelectric vibrator body 2
A plurality of protrusions 26 formed by the above-described method are formed on the surfaces of the upper and lower drive electrodes 2 in the vicinity of the node point 9. In this embodiment, the protrusions 26 ... Are provided in a dot shape, but in some cases, they may be formed in a single linear shape.

FIG. 4 shows the BB cross section of FIG. 3 in a state of being pressed by the actual external electrode 4, and the tip of the protrusion 26 bites into the external electrode 4 and is firmly held. In this case, if a relatively soft material such as Cu is selected as the external electrode 4, the biting effect is increased and the holding is stabilized. Further, since the respective projections 26 ... Can secure a uniform shape by the above-described manufacturing method, the bite and the posture thereof are stable, and the vibration of the piezoelectric vibrator main body 29 is stable.

Further, according to this embodiment, since the ultrafine particles 25 are used when forming the protrusions 26, the shape of the nozzle 15 can be made equal to or smaller than the width of the protrusions 26. There is no need for a mask or the like, which is necessary in the case of a method such as the thermal spraying method, and it is possible to flexibly deal with the formation of the protrusion 26. The projection 26 may be formed on the surface of the piezoelectric substrate 1 on which the driving electrode 2 is provided.

Further, according to the present invention, when the protrusions are formed, the piezoelectric vibrator is not subjected to a heat load as compared with the conventional thermal spraying method or printing method, so that the vibrator having stable characteristics is obtained. Is what you can get.

[0020]

According to the piezoelectric vibrator and the method of manufacturing the same of the present invention, since the protrusions are formed of ultrafine particles of a conductive material, the protrusions have a uniform cross-sectional shape with a slightly sharp tip. As a result, the contact with the external electrode is stable, and very stable characteristics can be secured as a piezoelectric vibrator. Further, by forming the protrusions of the piezoelectric vibrator by spraying ultrafine particles from the nozzles, the protrusions can be freely and accurately formed at predetermined locations. Therefore, it becomes possible to form the protrusion having excellent stability.

[Brief description of drawings]

FIG. 1 is a schematic view showing a method of manufacturing a piezoelectric vibrator according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view showing details thereof.

FIG. 3 is a perspective view of a piezoelectric vibrator body according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a holding state of the piezoelectric vibrator according to the embodiment of the present invention.

FIG. 5 is a perspective view of a conventional piezoelectric vibrator body.

FIG. 6 is an explanatory diagram showing a holding structure of a conventional piezoelectric vibrator.

FIG. 7 is a schematic view of a holding portion of a conventional piezoelectric vibrator.

[Explanation of symbols]

 1 Piezoelectric Substrate 9 Protrusion Forming Chamber 11 Evaporating Chamber 14 Pipe 15 Nozzle 26 Protrusion

Claims (5)

[Claims] 1. A piezoelectric substrate and two piezoelectric substrates facing each other.
Drive electrodes provided on one surface, a surface of the piezoelectric substrate on which the drive electrodes are provided in the vicinity of a node point of the piezoelectric substrate, or a conductive protrusion provided on the drive electrode surface, and the protrusion. 1. A piezoelectric vibrator, comprising: an external electrode, a portion of which is in contact with and held by the external electrode, wherein the protrusion is made of ultrafine particles of a conductive material. 2. The piezoelectric vibrator according to claim 1, wherein a plurality of protrusions are provided in a dot shape. 3. A conductive protrusion is provided on a surface of the piezoelectric substrate on which the driving electrode is provided or on the surface of the driving electrode, in the vicinity of a node point of the piezoelectric substrate provided with the driving electrode on two opposite surfaces. A method for manufacturing a piezoelectric vibrator, comprising forming ultra-fine particles of a conductive material from a nozzle having an inner diameter equal to or less than the width of the protrusion to form the protrusion. . 4. A piezoelectric substrate is installed in the protrusion forming chamber, and a conductive material is melted and evaporated in a vacuum in an evaporation chamber connected to the protrusion forming chamber by a pipe and then cooled by gas to form ultrafine particles. 4. The piezoelectric vibrator manufacturing method according to claim 3, wherein the ultrafine particles are ejected from a nozzle provided at a tip of the pipe in the protrusion forming chamber by a pressure difference between the evaporation chamber and the protrusion forming chamber. Method. 5. The method of manufacturing a piezoelectric vibrator according to claim 3, wherein the nozzle or the piezoelectric substrate is scanned in a predetermined movement pattern to form the protrusion in a linear shape or a dot shape.