JPH06338753A - Piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To realize the piezoelectric oscillator for which the holding structure, which is stable and reduces the charateristic very little, is realized. CONSTITUTION:The lengthwise oscillation mode is excited in a piezoelectric oscillator 1 like a rectangular plate whose principal face an electrode 2 is attached to. A metal which has a minute ruggedness on the surface and has a relatively high hardness is linearly attached as metallic projecting materials 3 in the vicinity of the nodal line in the center part of the rectangular plate by thermal spraying or the like. Springs 4 as holding tools are made of a metal whose hardness is lower than that of metallic projecting materials 3. The piezoelectric oscillator 1 is caught between springs 4 from above and below through metallic projecting materials 3 and is held and is pressurized with a certain force by cases 5 and screws 6. Since metallic projecting materials 3 have a minute ruggedness on the surface to bite into the contact parts of springs 4 by the difference of hardness, the piezoelectric oscillator 1 is stably held.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrator holding structure using a piezoelectric material such as piezoelectric ceramic, crystal, niobium lithium oxide or the like.

[0002]

2. Description of the Related Art A conventional structure of a piezoelectric vibrator holding structure using a piezoelectric material such as piezoelectric ceramics, crystal, niobium lithium oxide or the like will be described below.

Piezoelectric vibrators used for mechanical filters, oscillators, etc. are made of materials such as piezoelectric ceramics, crystal, niobium lithium oxide, etc., and an appropriate vibration mode is excited by the piezoelectric effect according to the frequency range to be used. . And
These piezoelectric vibrators are configured as a filter or an oscillator by holding them near a node where the vibration amplitude is 0 so as not to suppress vibration. Since these nodes are points or lines that do not have an area, ideally it is desirable to hold the piezoelectric vibrator at ideal points or lines, but in reality it is a stable holding of the piezoelectric vibrator. In order to realize the above, a certain finite area is held and held.

FIG. 5 is a perspective view of a rectangular plate type piezoelectric vibrator 11 made of a piezoelectric material such as a piezoelectric ceramic. Electrodes 12 are formed on two main surfaces facing each other, and an electric field is applied between the electrodes. Then, the spreading vibration of the square plate is excited. The node of this vibration mode is a point at the center of the square plate. Conventionally, as shown in the same figure, the vicinity of the center of the piezoelectric vibrator is piezo-electrically driven by a holder 13 having a spring-like property having a circular flat end. It was held from both sides of the oscillator.

FIG. 6 is a perspective view of a rectangular plate type piezoelectric vibrator 14 made of a piezoelectric material. Similarly, driving electrodes are formed on two opposing main surfaces. A length vibration is excited in this rectangular plate, and in the length vibration, the node of vibration is linear in the center of the rectangle. Holding device 15 having a spring-like shape
Was held in.

[0006]

In the conventional holding structure for a piezoelectric vibrator such as a filter or an oscillator, the piezoelectric vibrator is directly held by a dot-shaped or linear holder having a certain area. In addition, when the holding area was made small so as not to deteriorate the characteristics, the holding became unstable, and the holding attitude of the vibrator changed when the impact force was applied by dropping or the like, and the characteristics also changed. Further, when the holding area is increased in order to stabilize the holding, the vibrating portion is pressed, and the vibration of the vibrator is suppressed, so that there is a drawback that the characteristics are deteriorated. That is, since the conventional piezoelectric vibrator holding structure directly holds the piezoelectric vibrator, it is difficult to realize stable holding with little influence on the vibrator characteristics, high reliability, and so on. There were challenges.

[0007]

In a piezoelectric vibrator using a piezoelectric material, a conductive protrusion such as a metal is formed on the piezoelectric vibrator so that the piezoelectric vibrator can be brought into contact with at least the piezoelectric vibrator. An electrically conductive material having a hardness lower than that of the electrically conductive protrusion is used for the portion, and the piezoelectric vibrator is held by the electrically conductive protrusion and the electrically conductive material portion having a low hardness of the holder.

[0008]

[Function] By the fine unevenness on the surface of the conductive projection such as metal formed on the piezoelectric vibrator, the conductive material at the contact portion of the holder of the piezoelectric vibrator with the piezoelectric vibrator bites due to the hardness difference. The piezoelectric vibrator can be stably held by being mechanically coupled. Even if the contact area between the piezoelectric vibrator and the holder is increased, the effective contact area can be reduced due to the fine irregularities on the surface of the protrusions, improving stability and reliability, and improving the characteristics. It is possible to realize the holding of the piezoelectric vibrator with less decrease in

[0009]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view of a piezoelectric vibrator used in a holding structure according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a rectangular plate-shaped piezoelectric vibrator made of a piezoelectric material such as piezoelectric ceramic, crystal, or niobium lithium oxide, and having electrodes 2 attached to two opposing main surfaces. By applying, a length vibration mode having a main displacement in the length direction of the vibrator 1 is excited. The node of this length vibration is linear in the central part of the rectangular plate, and in the vicinity of this node line there is a metal with a relatively high hardness such as nickel-chromium alloy or nickel-chromium-aluminum alloy with fine irregularities on the surface. The metal projections 3 are attached linearly by a method such as thermal spraying.

FIG. 2 is a side view showing the holding structure of the piezoelectric vibrator 1 of FIG. 1, and the spring 4 as a holder is made of a metal having a hardness smaller than that of the metal projection 3 such as brass, copper alloy, or aluminum alloy. Is made. The piezoelectric vibrator 1 is held so as to sandwich the piezoelectric vibrator 1 from above and below by a spring 4 via a metal protrusion 3, and is pressed by a case 5 and a screw 6 with a constant force.

FIG. 3 shows the state of contact between the metal projection 3 and the spring 4 of the piezoelectric vibrator 1 thus held. Since the metal protrusion 3 has fine irregularities on its surface and digs into the contact portion of the spring 4 due to the difference in hardness, the piezoelectric vibrator 1 is stable even if the contact area between the piezoelectric vibrator 1 and the spring 4 serving as a holder is reduced. Can hold 1.

In the above embodiments, the piezoelectric vibrator is formed of a metal having a relatively high hardness, such as nickel-chromium alloy or nickel-chromium-aluminum alloy, as the electrically conductive protrusions. Metals such as brass, copper alloys or aluminum alloys can be used. Further, the same effect can be obtained even if ceramic has conductivity. In this embodiment, thermal spraying can be used as the method for forming the electrically conductive protrusions, but other methods such as sputtering, vapor deposition, CVD, plating or printing can be easily used.

In the above embodiment, brass, copper alloy, aluminum alloy is used for the spring as the holder of the piezoelectric vibrator. However, as shown in FIG. 4, it contacts a material such as stainless steel or spring steel. The same effect can be obtained by forming a low-elasticity protrusion 7 made of a material having a hardness smaller than that of an electrically conductive protrusion such as brass, a copper alloy, an aluminum alloy, a lead alloy, or a solder, or an electrically conductive ceramic at only the portion. It goes without saying that you can get it. Further, in the above embodiment, the rectangular plate is used as the piezoelectric vibrator, but it is needless to say that the same effect can be obtained even with a piezoelectric vibrator using a contour or a spreading vibration mode such as a square plate and a circular plate. Yes.

[0015]

EFFECTS OF THE INVENTION Piezoelectric vibrations are formed by forming electrically conductive protrusions on a piezoelectric vibrator, and using a material having a hardness lower than that of the electrically conductive protrusions for the contact portion of the piezoelectric vibrator at least with the holder. By holding the piezoelectric vibrator through the conductive projection and the material part of the holder having a low hardness, the fine unevenness on the surface of the conductive projection formed on the piezoelectric vibrator causes By digging into the material of the contact portion of the holder due to the hardness difference, it is possible to mechanically bond and stably hold the piezoelectric vibrator. Even if the contact area between the piezoelectric vibrator and the holder is increased, the effective contact area can be reduced due to the fine irregularities on the surface, improving stability and reliability, and lowering the characteristics. It is possible to realize the reduced holding of the piezoelectric vibrator.

[Brief description of drawings]

FIG. 1 is a perspective view of a piezoelectric vibrator used in a holding structure according to an embodiment of the present invention.

FIG. 2 is a holding structure diagram of a piezoelectric vibrator according to an embodiment of the present invention.

FIG. 3 is an enlarged view of a contact portion of a holding structure according to an embodiment of the present invention.

FIG. 4 is an enlarged view of a contact portion of a holding structure according to another embodiment of the present invention.

FIG. 5 is a perspective view of a conventional holding structure for a rectangular plate type piezoelectric vibrator.

FIG. 6 is a perspective view of a conventional holding structure for a rectangular plate type piezoelectric vibrator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric vibrator 2 Electrode 3 Conductive metal projection 4 Spring as a holder 5 Case 6 Screw 7 Low elasticity projection

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Nagasawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A piezoelectric vibrator using a piezoelectric material, wherein a conductive protrusion such as a metal is formed on the piezoelectric vibrator, and at least a holder for the piezoelectric vibrator is in contact with the piezoelectric vibrator. A conductive material having a hardness smaller than that of the conductive protrusion is used to hold the piezoelectric vibrator through the conductive protrusion and the material having a low hardness of the holder. Characteristic piezoelectric vibrator. 2. A material such as a nickel-chromium alloy, a stainless steel alloy, tungsten, brass, a copper alloy or an aluminum alloy, or a conductive ceramic is used as a material for the conductive protrusion formed on the piezoelectric vibrator. As a method of forming the projections, thermal spraying, sputtering, vapor deposition, CVD, plating or printing is used, and at least the holder of the piezoelectric vibrator is used as a conductive material of the contact portion with the piezoelectric vibrator, brass, copper alloy, The piezoelectric vibrator according to claim 1, wherein a metal such as an aluminum alloy, a lead alloy or solder, or a conductive ceramic is used.