JPH10242788A - Piezoelectric component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the piezoelectric component in which a sheathing resin is smoothed in an excellent way and the manufacture process is simplified. SOLUTION: The component is formed by adhering a couple of lead terminals to a piezoelectric element 1 that is formed by arranging vibration electrodes 11, 12 opposed to each other on both major sides of a rectangular box shaped piezoelectric substrate 10 and extended to an end of the substrate 10 and by covering the piezoelectric element 1 with a sheathing resin 5 so as to form a vibrating space in the inside. In this case, plates 23, 33 arranged almost in parallel at a prescribed interval S from the one major side of the piezoelectric substrate 10 are formed integrally to at least one of the lead terminals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric component in which a piezoelectric element is connected to a lead terminal and covered with an exterior resin.

[0002]

2. Description of the Related Art A lead type piezoelectric component in which a piezoelectric element is joined between a pair of lead terminals and the piezoelectric element is covered with an exterior resin has been widely known. In general, in a piezoelectric element, vibration electrodes facing each other and extending at both ends of the piezoelectric substrate are formed on both main surfaces of a rectangular parallelepiped piezoelectric substrate. The upper end of the lead terminal serves as a connection with the end of the piezoelectric element. Then, a part of the vibrating electrode extending to the end of the piezoelectric element is joined to the connection part of the lead terminal with a conductive adhesive. The covering structure of the piezoelectric element has an internal space (vibration space) centered on a vibration region of the piezoelectric element, that is, a portion formed on both main surfaces of the piezoelectric substrate and where the vibration electrodes face each other.
Is formed, and the periphery of the piezoelectric element is covered with an exterior resin. Specifically, a wax or the like in a molten state is dropped on a portion corresponding to a vibration space of the piezoelectric element, that is, on a central portion of both main surfaces of the piezoelectric substrate. The dropped wax has a substantially hemispherically raised shape on the main surface of the piezoelectric substrate, and is naturally cured in this shape. It is necessary to drop wax on both main surfaces of the piezoelectric substrate. This state is shown in FIG. FIG. 6 is a plan view as viewed from above, where 61 is a piezoelectric element, 62 is a piezoelectric substrate, 63 and 64 are vibrating electrodes, 65 and 66 are lead terminals, and 67 and 68 are dripped wax. The upper end of the lead terminal shown in the figure is processed into a substantially U-shape, and serves as a connection part that holds the end of the piezoelectric element 1.

In this state, a powder resin as an exterior resin is applied so as to cover the entire periphery of the piezoelectric element, and the powder resin is subjected to a thermosetting treatment to form an exterior resin. The wax and the like are melted by the thermosetting process of the exterior resin and are absorbed in the exterior resin. Thus, the absorbed wax portion becomes a vibration space on the piezoelectric substrate.

[0004]

As described above, since the vibrating space is formed in a substantially hemispherical shape of wax dropped on both main surfaces of the piezoelectric substrate, the surface shape of the exterior resin is substantially hemispherical. Will be affected by the shape of the wax. That is, the outer resin surface of the vibrating portion of the piezoelectric element projects.

[0005] Although it is necessary to make markings indicating the model number and characteristics of the piezoelectric component on the surface of the exterior resin, it has been difficult to easily perform the marking because the surface of the conventional exterior resin has poor flatness. .

In the assembling process, it is necessary to drop wax from both main surfaces of the piezoelectric element to form a vibration space, which complicates the operation.

The present invention has been devised in view of the above-mentioned problems, and has as its object to provide a piezoelectric component which has improved flatness of the surface of an exterior resin and has a simplified manufacturing process. is there.

[0008]

According to the present invention, there is provided a piezoelectric element comprising a rectangular parallelepiped-shaped piezoelectric substrate, and vibrating electrodes arranged on both main surfaces of the piezoelectric substrate, the vibrating electrodes being opposed to each other and extending to an end of the substrate. A piezoelectric element comprising: a pair of lead terminals joined to the vibrating electrode at the ends of the pair; and an exterior resin for covering the piezoelectric element so as to form a vibration space therein. A piezoelectric component, wherein a plate-like body arranged substantially parallel to one main surface of the piezoelectric substrate at a predetermined distance from the terminal is formed integrally with the terminal.

[0009]

As described above, at least one of the pair of lead terminals is roughly arranged at a predetermined interval on one main surface of the piezoelectric element, and a plate-like body is arranged.

Therefore, the flatness of the surface of the exterior resin on the one main surface side of the piezoelectric element is improved depending on the plate-like member.
For this reason, the surface of the exterior resin on this side can be easily margined to indicate the model number and the like of the component, and can be formed clearly.

In forming a vibration space around the piezoelectric element, wax is dropped on the piezoelectric element. In this case, the wax dropped on the other main surface of the piezoelectric element is applied to one side of the piezoelectric element. It will be drawn between the gap between the surface and the plate. That is, conventionally, the dripping was performed from two directions of the other main surface side and the one main surface side of the piezoelectric element. However, in the present invention, the wax dripping step is completed by a single dripping from the other surface side. . Therefore, in the assembling process, the number of processes is simplified.

Further, since the wax dropped on the other main surface is drawn into the one main surface, the amount of wax remaining on the other main surface of the piezoelectric element is reduced, and the amount of swelling is reduced. That is, when the exterior resin is formed, in addition to the flatness of the exterior resin on the main surface side, which is affected by the flatness of the plate-like body, the flatness due to the decrease in the amount of unevenness due to the decrease in the amount of protrusion on the other main surface side This makes it possible to easily and sharply mark the surface of the exterior resin on the other main surface side.

This means that, for example, even when another element, for example, a capacitance element forming two capacitance components is arranged on the outer side of the plate-like body, one main surface of the exterior resin is connected to the capacitance element. The flatness is improved by affecting the smoothness, and at the same time, the flatness of the surface of the exterior resin on the other main surface side (the side where the wax is dropped) of the exterior resin is excellent, and clear marking can be easily formed. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a piezoelectric component according to the present invention will be described in detail with reference to the drawings.

The piezoelectric component of the present invention shown in FIGS. 1 to 4 will be described by taking a piezoelectric resonator constituted by one piezoelectric element and a pair of lead terminals as an example.

FIG. 1 is an external perspective view of the piezoelectric component, FIG. 2 is a plan sectional view showing the vicinity of the tip of the lead terminal, and FIG.
FIG. 4 is an exploded perspective view in a state where the exterior resin is omitted, and FIG.
FIG. 4 is a plan view of a state where wax is dropped.

In FIG. 1, reference numeral 1 denotes a piezoelectric element;
Is a lead terminal, 4 is a vibration space, 5 is an exterior resin, and 6 is a marking such as a model number of a part.

The piezoelectric element 1 is, as shown in FIGS.
The piezoelectric substrate 10 is made of a piezoelectric ceramic such as lead zirconate titanate, has a substantially rectangular parallelepiped shape as a whole, and has been subjected to a predetermined polarization process according to a vibration mode.

On both main surfaces of the rectangular parallelepiped piezoelectric substrate 10, rectangular vibrating electrodes made of Ag-based material (Ag or Ag alloy) or Cu-based material (Cu or Cu alloy) facing each other are provided. 11 and 12 are formed. At one end in the longitudinal direction of the piezoelectric substrate 10, an extraction electrode 13 connected to the vibration electrode 11 is formed, and at the other end, an extraction electrode 14 connected to the vibration electrode 12 is formed. .
The extraction electrodes 13 and 14 are made of the same material as the vibrating electrodes 11 and 12, and are formed over one main surface, an end surface, and the other main surface of each end.

As shown in FIG. 3, the lead terminals 2 and 3 are formed of a metal member such as phosphor bronze or Kovar, and the upper end thereof has a connecting portion 21 connected to the extraction electrodes 13 and 14 of the piezoelectric element 1. It is 31. In addition, the connection portions 21 and 3
Lead portions 22, 32 extend from 1 to the lower end.
Further, both lead terminals 2 and 3 are plate-like bodies (flag portions) 2 extending from connecting portions 21 and 31 toward the other lead terminals 2 and 3.
3 and 33 are formed.

When the piezoelectric element 1 is arranged on the lead terminals 2 and 3, the flag parts 23 and 33 are connected to the joints between the flag parts 23 and 33 and the connection parts 21 and 31 on one main surface of the piezoelectric element 1. A bending process is performed so as not to contact the vibration electrode 11. As a result, a predetermined space S is formed between the one main surface of the piezoelectric element 1 and the flag portions 23 and 33 of the lead terminals 2 and 3. Note that the predetermined interval S is 50 to 200 μm.
The planar shape of the flag portions 23 and 33 is substantially the same as or slightly larger than the width of the piezoelectric substrate 10 in the height direction of the lead terminals 2 and 3. Together, the length of the piezoelectric substrate 10 is substantially the same or slightly smaller. In the drawing, the dimension is slightly smaller than half the length of the piezoelectric substrate 10, and a predetermined interval D is formed between the two. This interval D is, for example, 0.5 to 1.0 mm.

The vibration spaces 41 and 42 are formed at least in portions where the vibration electrodes 12 and 13 formed on both main surfaces of the piezoelectric substrate 10 are opposed to each other. The upper and lower ends of the substrate 10 may communicate with each other to form a single space. Here, the vibration spaces 41 and 42 formed on both main surfaces are collectively referred to as a vibration space 4. Here, the space 41 on the one main surface side is formed by the gap S between the piezoelectric element 1 and the flag portions 23 and 33, and the space on the other main surface side is formed by dripping of wax described later. It is formed by

The exterior resin 5 is made of an epoxy resin or the like, and is formed so as to completely cover the piezoelectric element 1 including the vibration space 4. Specifically, it is formed by applying a resin powder such as an epoxy resin and performing a thermosetting treatment. Note that the exterior resin 5 may have a laminated structure including an inner resin and an outer resin. It is important for the exterior resin of this laminated structure that ceramic powder is mixed in the inner resin to promote absorption of the wax, and that a dense resin layer is formed in the outer resin. is there.

The marking 6 is printed on the surface of the exterior resin 5 and is used to create the model number, type, and characteristics of the piezoelectric component. For example, the marking 6 is formed by printing a resin paste containing a pigment, a dye, and the like. It is formed by doing.

According to the present invention, the flag portions 23 and 33 formed on the lead terminals 2 and 3 are provided on one main surface of the piezoelectric element 1 in a predetermined space S.
Is formed along one main surface of the piezoelectric element 1 with a gap of. When the exterior resin 5 is formed, the flatness of the surface of the exterior resin 5 on one main surface side is improved due to the influence of the planar flag portions 23 and 33. Therefore, when the marking 6 is printed on this surface, it is possible to print it very easily and clearly.

Next, the process of assembling the piezoelectric component having the above-described structure will be described.

First, as shown in FIG. 3, a piezoelectric element 1 and a pair of lead terminals 2 and 3 are prepared.

Note that the lead terminals 2 and 3 are
32 are connected at the lower end by a common frame,
The connecting portions 21 and 31 of the lead terminals 2 and 3 have dimensions of the piezoelectric element 1.

Next, the piezoelectric element 1 is connected to the pair of lead terminals 2 and 3 by, for example, soldering so that the connection portions 21 and 22 of the lead terminals 2 and 3 and the extraction electrodes 13 and 14 of the piezoelectric substrate 10 are connected. Connection via a conductive adhesive such as Thereby, a predetermined space S is formed between the vibration electrode 11 formed on one main surface of the piezoelectric substrate 10 and the flag portions 23 and 33 of the lead terminals 2 and 3.

Next, a molten wax (specifically, paraffin) 43 is dropped from the other main surface of the piezoelectric element 1 to form a vibration space 4 in the center of the piezoelectric element 1. Here, the wax 43 to be dropped is spread to a portion slightly protruding from the width of the piezoelectric element 1. This allows
On the other main surface side of the piezoelectric element 1, the molten wax 43 is arranged in a raised state, and at the same time, the molten wax slightly protruding from the width of the piezoelectric element 1 is placed in the space S on the one main surface side of the piezoelectric element 1. Wrap around. This is drawn by the distance of the space S and the melted surface tension.

In the figure, since a gap of a predetermined distance D is formed between the flag portions 23 and 33, the molten wax 43 dropped on the other main surface side is positively drawn into the space D. As a result, the space 44 on the one main surface side of the piezoelectric element 1 is filled with the wax 44. This state is shown in FIG.

In FIG. 4, the dotted line in FIG. 4 shows a swelling state of the wax which is dropped on the other main surface side of the piezoelectric element in the piezoelectric component having the conventional structure. On the other hand, as in the present invention, one main surface side of the piezoelectric element 1 and the flag 2
Since the wax 44 is drawn into the gap of the predetermined space S between the third and the third 33, the swelling amount of the wax 43 remaining on the other main surface side is reduced. Further, the gap on the one main surface side is filled with wax 44. The dripped molten wax 43, 44 immediately becomes a solid state on both main surfaces.

Next, the powder resin to be the exterior resin 5 is applied to the waxes 43 and 44 remaining on both main surfaces of the piezoelectric element 1, the connection portions 21 and 31 of the lead terminals 2 and 3, the flag portions 23 and 33, and the lead portions. Is applied to the periphery of the piezoelectric element 1 so as to include a part of the piezoelectric element 1.

Next, the resin adhered and applied around the piezoelectric element 1 is treated with heat at 150 to 200.degree. As a result, the powder resin becomes the exterior resin 5 by thermosetting, and the waxes 43 and 44 are again melted by heat and absorbed by the exterior resin 5.

As a result, the portions of the waxes 43 and 44 disposed on both main surfaces of the piezoelectric element 1 become vibrating spaces 42 and 4.
It becomes 2.

Next, predetermined characters and symbols are marked 6 on the surface of the exterior resin 5 using a colored resin paste mixed with a pigment or a dye. The marking 6 is formed only by drying, but may be formed before the heat treatment of the exterior resin 5 because the marking 6 is cured simultaneously with the thermosetting treatment of the exterior resin 5.

In the above-described piezoelectric component assembling process, the dropping of the wax for forming the vibration space 4 of the piezoelectric element 1 is completed by a single dropping from the other main surface side of the piezoelectric element 1. This is because the flag portions 23 and 33 extending from the lead terminals 2 and 3 are structurally arranged such that a predetermined space S is formed on one main surface side of the piezoelectric element 1.

The wax dropped on the other main surface of the piezoelectric element 1 easily wraps around the one main surface side, and eventually, the piezoelectric element 1
By dropping the wax once from the other main surface side, the wax can be left and arranged on the surface of the piezoelectric element 1 on both main surface sides, and the assembly process can be simplified.

The part of the wax 43 dropped on the other main surface of the piezoelectric element 1 is drawn into the space S on the one main surface of the piezoelectric element 1, so that the wax 43 on the other main surface of the piezoelectric element 1 is removed. Can be formed with a reduced thickness, so that the unevenness of the surface shape of the exterior resin 5 can be eliminated, and the marking 6 can be easily formed on the surface of the exterior resin 5 corresponding to the other main surface. Can also.

Further, the thickness of the exterior resin 5 covering the piezoelectric element 1 is reduced, and a thin piezoelectric component is obtained.

In the above-described embodiment, the flag portions 23 and 33 extend from both the lead terminals 2 and 3, respectively. However, the flag portions 23 and 33 may extend from only one of the lead terminals 2 and 3. .

FIG. 5 is a plan sectional view of a three-terminal type piezoelectric component having a capacitive element 7 forming two capacitive components. The capacitor substrate 7 is bonded to the outer main surfaces of the flag portions 23 and 33 shown in FIGS.

The capacitive element 7 has, for example, individual capacitive electrodes 71, 72, 7 on both ends of both main surfaces of the dielectric substrate 70, respectively.
3, 74 are formed. That is, a first capacitance component is generated at a portion where the individual capacitance electrodes 71 and 73 oppose each other, and a second capacitance component is generated at a portion where the individual capacitance electrodes 72 and 74 oppose each other.

The capacitance element 7 includes, for example, an individual capacitance electrode 7
Reference numerals 1 and 72 are joined to the main surfaces on the outer sides of the flag portions 23 and 33 of the lead terminals 2 and 3 via a conductive adhesive. Further, a third lead terminal 8 commonly connected to the individual capacitance electrodes 73 and 74 is connected via a conductive adhesive.

The exterior resin 5 is formed so as to cover the whole of the piezoelectric element 1 and the capacitive element 7 and to form the vibration space 4 on the other main surface and the one main surface side of the piezoelectric element 1. .

As described above, the vibration space 4 is formed only by the dripping of the wax from the other main surface of the piezoelectric element 1, and the piezoelectric element 1 and the flag portions 23, 3
3 will be formed.

In this embodiment, the capacitance element 7 of the exterior resin 5 is used.
Although the shape of the third lead terminal 8 directly affects the surface of the piezoelectric element 1, the wax forming the vibration space 4 is drawn into the one main surface of the piezoelectric element 1. Accordingly, the thickness of the vibration space 4 is reduced in a relatively large area, so that the fluctuation of the unevenness is eliminated, and the formation of the margining 6 on this surface is facilitated.

[0048]

According to the present invention, at least one of the pair of lead terminals is formed integrally with the flag portion facing the main surface at a predetermined distance from one main surface of the piezoelectric substrate. The flatness of the surface of the exterior resin on the flag portion side is improved.

When a vibration space is formed around the piezoelectric element, wax or the like is dropped, and the wax dropped from the other main surface of the piezoelectric element causes the gap between the one main surface of the piezoelectric element and the flag portion to drop. In between, you will be drawn in,
With a relatively large area on the other main surface of the piezoelectric element, it is possible to drip the wax in a relatively thin state.
A thin vibration space is created. This also improves the planarity of the surface of the exterior resin on the piezoelectric element side.

As described above, by improving the smoothness of the surface of the exterior resin, the formation of markings and the like formed on the exterior resin of the piezoelectric component becomes easy and clear.

Further, only one dropping step is required, and the number of manufacturing steps can be reduced.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a piezoelectric component of the present invention.

FIG. 2 is a plan sectional view of a piezoelectric element according to the present invention.

FIG. 3 is an exploded perspective view in a state where an exterior resin of the present invention is omitted.

FIG. 4 is a plan view showing a state where wax is dropped.

FIG. 5 is a plan sectional view of a piezoelectric element showing another embodiment of the present invention.

FIG. 6 is a plan sectional view of a conventional piezoelectric component in a state where wax is dropped.

[Explanation of symbols]

 1 ··· Piezoelectric element 2 · 3 ··· Lead terminal 4 ··· Vibration space 5 ··· Exterior resin 6 ··· Marking

Claims (1)

[Claims] 1. A piezoelectric element having two main surfaces of a rectangular parallelepiped piezoelectric substrate provided with vibrating electrodes facing each other and extending to an end of the substrate, and joined to the vibrating electrode at the ends of the piezoelectric element. A piezoelectric component comprising: a pair of lead terminals; and an exterior resin for covering the piezoelectric element so as to form a vibration space therein, wherein at least one of the lead terminals has one main surface of a piezoelectric substrate. And a plate-like body arranged substantially in parallel with a predetermined interval from the piezoelectric element.