JPS6028405B2 - piezoelectric resonator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric ceramic resonator such as an energy trap type ceramic filter.

Conventionally, in order to obtain a piezoelectric ceramic resonator made by enclosing a pressure crab element with electrodes, which constitutes a ceramic filter as described above, the piezoelectric element is heated to a predetermined temperature and immersed in powder such as epoxy resin. The method of doing this is used, but
In this method, it is necessary to protect the working electrode part so that the coating resin does not come into direct contact with the working electrode part, or to form a gap.

As a means for forming voids, for example, Japanese Patent Publication No. 50-237
However, in this method, partially removing the adhesive layer is complicated and time-consuming, and the removal contour is unclear, and it is difficult to remove the adhesive layer partially. It is difficult to do so. In addition, the thickness of the adhesive layer was set to 100
It is difficult to obtain a thickness of more than microns, and a gap of several tens of microns poses the problem that the substrate with the adhesive layer easily comes into contact with the working electrode surface due to external force or temperature changes.

The present invention solves such problems and will be explained below with reference to the drawings shown as examples.

In FIG. 1, reference numeral 1 denotes a piezoelectric element constituting an energy trapping ceramic filter, which has electrodes 2 and 3 for input and output, respectively, on one main plane of a rectangular electrical substrate la; It is constructed by arranging grounding electrodes (common electrodes) 4 facing each other in a pattern as shown in the figure on the other main plane. Figure 2 A, B
is a plan view of the insulator substrate 5 on which the piezoelectric element is mounted, and
In the 1×, line cross-sectional view, conductors 2', 3', and 4' of a predetermined pattern are provided on one main plane of the insulating substrate 5, and at their ends and on one side of the insulating substrate 5. External connection terminals 6a, 6b, and 6c are attached to the portions located on the twill portions with solder 7 or the like.

The substrate 5 is made of a resin such as phenol, epoxy, or polyimide, and a printed board with copper foil adhered to the surface is etched into a predetermined pattern to form the conductors 2', 3', 4', or one in which a predetermined conductive film pattern is formed on a ceramic substrate such as steatite, alumina, etc. or a glass substrate by means of plating, vapor deposition, baking, etc. can be used. Conductor 2' of the above-mentioned insulator substrate
, 3', 4' are further provided with a conductive adhesive 8 (for example, silver paste) in a predetermined pattern by printing or other means.

3A and 3B, the piezoelectric element 1 of FIG. 1 is adhered to a predetermined position on the insulating substrate 5 of FIG. This figure shows the state in which .

The formation of protrusions at the corners extends over the four corners of the piezoelectric substrate la, that is, near the ends of the electrodes 2, 3, and 4 of the electrical element 1, and the conductive adhesive 8 printed on the insulator substrate 5. This is carried out by applying conductive adhesive 9 in dots. Therefore, each electrode 2, 3, 4 of the piezoelectric element 1 and each conductor 2', 3', 4' of the insulating substrate 5 are electrically connected to each other by the conductive adhesives 8, 9. Ru. In this embodiment, the height of the dot-like protrusions (hereinafter referred to as A) formed with conductive adhesive 9 at the corners of each electrode 2, 3, 4 of the piezoelectric element 1 is The shape and dimensions were such that it was 200 to 300 microns higher than the working electrode surface. 4A and 4B are partially cutaway plan views showing a state in which the lid body 10 is attached to the insulator substrate 5 on which the piezoelectric element 1 shown in FIG. 1 is attached, that is, the one shown in FIG. 3, and
−× Yazuka sectional view.

FIG. 5 is a perspective view showing an example of the lid 10 in an unattached state, in which a thermosetting or pressure-sensitive adhesive layer 11 made of an insulating material is coated on one side of a rectangular base material such as a polyester film. It is made by coating and generally commercially available as a single-sided adhesive tape at low cost.

The exterior structure of the present invention is such that a gap is formed on the working electrode surface of the piezoelectric element 1 using the above-mentioned lid 10 and the dot-like protrusions A formed with a conductive adhesive.The assembly will be described below. Explain the process.

As shown in FIGS. 4A and 4B, the lid is attached to the insulating substrate 5 on which the piezoelectric element 1 is attached using the adhesive layer 11 through the dot-like protrusions A so that the lid 10 accommodates the piezoelectric element 1. Attach.

In this case, it is desirable that the external dimensions of the lid 10 be such that the width is comparable to that of the insulating substrate, and the length is such that it does not cover the external connection terminals 6a, 6b, and 6c. As is clear from FIG. 4B, even if the lid is attached so as to form an adhesive part around the outer shape of the piezoelectric element, the adhesive layer of the body will not be able to generate piezoelectricity due to the protrusions A formed at the corners of the piezoelectric element. A gap 12 is formed without direct contact with the working electrode portion of the element 1. After forming a predetermined gap 12 in the working electrode portion of the piezoelectric element 1 as described above, the adhesive layer 11 of the lid body 10 is
After that, the entire insulating substrate 5 including the piezoelectric element 1 and the lid 10 is immersed in a thermosetting powder such as epoxy resin or a liquid resin bath that hardens at room temperature (none of which are shown). By forming a resin coating layer and curing it by heating at a predetermined temperature, the piezoelectric element 1 can be kept in a sealed state completely shielded from the outside air.

- Note that the dot-shaped protrusions A applied to the corners of the piezoelectric substrate la of the piezoelectric element 1 do not need to be limited to a conductive adhesive, and an insulating adhesive such as epoxy resin may also be used.

The dot application position is not limited to the corner of the piezoelectric substrate la, but can be anywhere near the external shape of the piezoelectric element as long as the dot-shaped protrusion or the lid body does not come into contact with the actuating electrode and have an adverse effect. It is clear that protrusions may also be formed at the locations. Further, the number of locations where dot-like protrusions are formed is not limited at all. Further, the present invention is not limited to a structure in which the piezoelectric element 1 is attached to an insulating substrate as shown in 5 above, but a piezoelectric substrate as illustrated in FIGS. 6A and 6B. A Shoden element configured by extending parts 2A, 3A, 4A of electrodes 2, 3, 4 attached to the main surface of la' and directly connecting external connection terminals 6a, 6b, 6c to the extended parts. This includes cases where 1' is used.

In this case, the dot-like protrusions A are arranged on both sides (or one side) so as to be located at a plurality of locations near the working electrode portion, and then the lid body 10 as illustrated in FIG. It may be adhered to both sides, and the whole may be hermetically covered with an insulating material such as epoxy resin. As described above, in the piezoelectric ceramic resonator of the present invention, a protrusion of a predetermined height is formed in the vicinity of the actuating electrode portion of the piezoelectric element using an adhesive resin member, and a cover member (for example, an inexpensive commercially available single-sided adhesive tape) is formed.
By bonding them together, a gap can be easily and efficiently formed in the working electrode part, and a piezoelectric ceramic resonator with stable electrical characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an example of a piezoelectric element used in the present invention, and FIGS. 2A and 2B are a plan view and a cross-sectional view along the 3A and 3B are a plan view and a sectional view taken along the line X2-X2 showing the piezoelectric element shown in FIG. 1 attached to the insulating substrate shown in FIG. FIG. 5 is a perspective view of an example of the lid body used in the present invention, and FIGS. 6A and B are views of other embodiments of the present invention. It is a partially cutaway plan view and a sectional view taken along the line -x4. 1, 1'... Piezoelectric element, 2, 3, 4... Electrode, 2'
, 3', 4'... Conductor, 5...... Insulator board, 6a, 6b, 6c...terminal for external connection, 8
, 9... Conductive adhesive, 10... Lid, 11...
...Adhesive layer, 12...Void, A...Dot-shaped protrusions. Figure 1 Figure 2 Figure 5 Figure 3 Figure 4 Figure 6

Claims (1)

[Claims] 1. A plurality of conductors are provided in a predetermined pattern, and
an insulator substrate connected to external connection terminals and a piezoelectric element having a plurality of electrodes to desired conductors;
The piezoelectric element is provided with a lid that covers the piezoelectric element, and the piezoelectric element is disposed on the insulating substrate, and each electrode of the piezoelectric element is electrically connected to a predetermined conductor of the insulating substrate. In addition, a protruding portion is formed on the edge of the piezoelectric element using an adhesive resin member, and the lid body is attached to the insulating substrate through the protruding portion so as to house the piezoelectric element, and the entire piezoelectric element is made of an insulating material. A piezoelectric ceramic resonator characterized by being hermetically coated with. 2. Claim 1 states that the lid uses an insulating member coated with either an adhesive adhesive or a thermosetting resin on one side. Features a piezoelectric ceramic resonator. 3. A piezoelectric ceramic resonator according to claim 1 or 2, characterized in that the protruding portion formed of the adhesive resin member is formed to protrude beyond the operating electrode surface of the piezoelectric element. 4. A piezoelectric element having a plurality of electrodes in a predetermined pattern that are directly connected to external connection terminals on a piezoelectric substrate having a predetermined shape, and a lid body that covers the operating electrode portion of the piezoelectric element. forming a plurality of protrusions using an adhesive resin member in the vicinity of the actuating electrode portion on at least one surface of the piezoelectric element, and attaching the lid through the protrusions, the piezoelectric element including the lid; A piezoelectric ceramic resonator characterized in that the entirety is hermetically covered with an insulating member. 5. Claim 4 states that the lid uses an insulating member coated with either an adhesive adhesive or a thermosetting resin on one side. Features a piezoelectric ceramic resonator. 6. A piezoelectric ceramic resonator according to claim 4 or 5, characterized in that the protruding portion formed of the adhesive resin member is formed to protrude beyond the operating electrode surface of the piezoelectric element.