JPS63302613A - Piezoelectric component - Google Patents

Abstract

PURPOSE:To miniaturize a piezoelectric filter, by holding an element with a support substrate, fixing a lead terminal and an intermediate lead terminal on the support substrate, and reducing the sizes of an end part draw-out electrode and the element. CONSTITUTION:The element 4 is superposed on the support substrate 31, and its end part is held with a holding part 32 formed on an end part lead terminal 33, and the end part draw-out electrode of the element 4 and the end part electrode 38 of the substrate 31 are connected conductively to the holding part 32 by a conductive bonding agent supplied to the holding part 32. And an end part 33 and the intermediate lead terminal 34 are bonded and fixed at the end part electrode 38 of the substrate 31 and an intermediate electrode 37. In such a way, stress given on the element 4 from the outside can be absorbed by the support substrate 31. Therefore, it is possible to reduce the size of the element 4, and to reduce the shape of the piezoelectric filter.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to piezoelectric components such as piezoelectric resonators and piezoelectric filters, and more particularly to a mounting structure for lead terminals of piezoelectric components.

(Prior Art) In recent years, with the miniaturization of electronic devices, there is a tendency for electronic components to be increasingly smaller.

Therefore, in a piezoelectric filter, for example, as shown in FIG. 4, a three-terminal resonator 2 is mounted on a narrow rectangular piezoelectric substrate 1 and utilizes the energy-confining thickness shear vibration mode of the piezoelectric substrate 1. Element 4 that formed ゜3
There are products on the market that have a lower profile. As shown in FIG. 4(a), one main surface of the piezoelectric substrate 1 is provided with an input electrode 5.of a three-terminal resonator. Output electrodes 6 and 3
Input electrode 7 of terminal type resonator 3. An output electrode 8 is formed, and end extraction electrodes 9 and 1 are provided at both ends, respectively. is formed. The input electrode 5 of the three-terminal resonator 2 is connected to the end extraction electrode 9 through the connection electrode 12, and the output electrode 6 of the three-terminal resonator 2 and the input electrode 7 of the three-terminal resonator 3 are connected. are connected to each other by electrodes 13, and 3
The output terminal 8 of the terminal type resonator 3 is connected to the current end extraction electrode 11 by a connecting electrode 14 . On the other hand, on another main surface of the piezoelectric substrate l, as shown in FIG. 4(b), ground electrodes 15 and 16 of the three-terminal resonators 2 and 3 are formed, An intermediate extraction electrode 17 is formed between and 16, and this extraction electrode 17 is connected to ground electrodes 15 and 16 by connection electrodes 18 and I9, respectively.

Conventionally, in a piezoelectric filter whose height has been reduced by using the narrow element 4 as described above, as shown in FIG.
Lead terminals 21, 22 and 23 in the form of lead pieces having a certain width are soldered directly to the end extraction electrodes 9, 11 and the intermediate extraction electrode 17 (see FIGS. 4(a) and (b)), and the piezoelectric substrate is assembled. The element 4 is covered with a rubber-like elastic body (not shown) such as silicone rubber so that the forming parts of the three-terminal resonators 2 and 3 of 1 can vibrate, and from above,
As shown in FIG. 6, it was covered with an exterior resin 24.

Incidentally, in the piezoelectric filter described above, the higher the filter frequency, the thinner the piezoelectric substrate l becomes.

For example, in a 4.5 MHz piezoelectric filter used in an audio intermediate frequency amplifier of a television receiver, etc., the piezoelectric substrate l has a very thin thickness of 275 μm. As described above, the lead terminals 21, 22 and 23 are directly soldered to the very thin piezoelectric substrate l, and the piezoelectric filter is covered with a rubber-like elastic body and the outer resin 24. There is a problem in that when stress is applied to the piezoelectric substrate 1, cracks or cracks occur in the piezoelectric substrate 1.

Furthermore, when attempting to reduce the height and size of the piezoelectric filter, the area of the piezoelectric substrate l is approximately determined by the filter frequency, so the end extraction electrodes 9 and ! (1) had to be made smaller, and when soldering the lead terminals 21 and 22, problems such as the end extraction electrodes 9 and 11 sometimes peeling off from the piezoelectric substrate l occurred, reducing reliability. .

(Object of the Invention) An object of the present invention is to provide a piezoelectric component that has high reliability and can be easily reduced in size and height.

(Structure of the Invention) Therefore, the present invention provides an element having an end extraction electrode and an intermediate extraction electrode at both ends and between them, respectively.A notch is formed at a position corresponding to the intermediate extraction electrode of the element. A support substrate is provided with an intermediate electrode and an end electrode formed at the position of the notch and at both ends, respectively, and the above-mentioned element is superimposed on the support substrate, and the end thereof is formed into an end lead terminal. an end electrode of the element and an end electrode of the support substrate are electrically conductively bonded to the holding part by a conductive adhesive supplied to the holding part;
The intermediate lead terminal fitted into the notch is electrically conductively bonded to the intermediate lead-out electrode of the element and the intermediate electrode of the support substrate by a conductive adhesive supplied to the notch of the support substrate. It is said that The element is adhered to the end electrode and intermediate electrode of the support substrate at its end extraction electrode and intermediate extraction electrode, and is held by the support substrate. Then, end lead terminals and intermediate lead terminals are bonded and fixed to the end electrodes and intermediate electrodes of this support substrate. As a result, stress applied to the element from the outside is absorbed by the support substrate.

(Effects of the Invention) According to the present invention, the element is held by the support board, and the end lead terminals and intermediate lead terminals are fixed to the support board, so that stress applied to the element from the outside is absorbed by the support board. absorbed,
A highly reliable piezoelectric component can be obtained without cracking or cracking in the piezoelectric substrate constituting the element.

Furthermore, according to the present invention, the end lead-out electrodes and the intermediate lead-out electrodes of the element need only be electrically connected to the end electrodes and the middle electrode of the support substrate through the conductive adhesive. By making the end electrodes and intermediate electrodes of the support board larger, even if the partial lead electrodes and intermediate lead electrodes are made smaller, the mounting strength of the end lead terminals and intermediate lead terminals does not deteriorate, and the piezoelectric component can be made smaller. can be achieved.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

A perspective view and an exploded perspective view of an internal structure of an embodiment in which the present invention is applied to a piezoelectric filter using an element 4 having the electrode configuration described in FIG. 4 are shown in FIGS. 1 and 2, respectively.

The piezoelectric filter includes an element 4, a support substrate 31 that holds this element 4, and these elements 4.
and a holding part 3 that holds the support board 31 at its end.
2, and an intermediate lead terminal 34 drawn out from between these two end lead terminals 33.33.

The support substrate 31 is made of a substrate 35 made of an insulating ceramic material such as alumina or an insulating resin material and having dimensions substantially equal to the piezoelectric substrate 1 of the element 4. This substrate 35 has a notch 36 at a position corresponding to the intermediate extraction electrode 17 of the element 4.
is formed. Further, on one main surface of the substrate 35, an intermediate electrode 37 and end electrodes 38, 38 are formed at the formation position of the notch 36 and at both ends, respectively.

On the other hand, as can be seen from FIG. 2, the holding portion 32 of each end lead terminal 33 has a cross section of U so as to hold the ends of the element 4 and the support substrate 31 which are overlapped with each other. It is formed into a letter shape. The holding portion 32 has an open upper end surface and side surfaces in order to fit the ends of the element 4 and the support substrate 31, and
A support plate 39 for the element 4 and the support substrate 31 is provided on the lower end surface. An end lead terminal 33 is attached to this support plate 39.

Further, the intermediate lead terminal 34 that is electrically connected to the intermediate lead-out electrode 17 of the element 4 has one end connected to the support substrate 35.
After fitting into the notch 36, the element 1 is bent in two steps along the intermediate lead electrode 17 of the element 1 superimposed on the support substrate 35.

The element 4 is overlapped from the intermediate lead-out electrode 17 side to the main surface of the support substrate 31 opposite to the main surface on which the intermediate electrode 37 and the end electrode 38 are formed, and its both ends are connected to each other. It is fitted into the holding part 32 of the lead terminal 33, and as shown in FIG. 3, this holding part 32 is supplied with a conductive adhesive 41 such as solder or conductive paste. As a result, the end lead electrode 9.11 of the element 1 is electrically conductively bonded to the end electrode 38.38 of the support substrate 31, and this end electrode 38.38 is connected to the end lead terminal 3.
3.33 is electrically conductively glued to the holding part 32.32. Furthermore, the conductive adhesive 4 is also applied to the notch 36 of the support substrate 31.
1 is supplied, and the intermediate lead terminal 34 is connected to the intermediate lead electrode 17 of the element 4 and the intermediate electrode 3 of the support substrate 31.
7 is electrically conductively bonded. In this state, the element 4 and the support substrate 3 are covered with a rubber-like elastic body and then coated with an exterior resin, as in FIG. 6.

With such a configuration, the element 4 is held by the support substrate 31, and the end lead terminals 33 and intermediate lead terminals 34 are substantially fixed by the end electrodes 38 and intermediate electrodes 37 of the support substrate 31. Therefore, even if force is applied to the end lead terminal 33 or the intermediate lead terminal 34, this force is absorbed by the support substrate 31 and the element 4
Do not apply excessive force to the This prevents cracks from being generated due to excessive force being applied to the element 4 during the manufacturing process of the piezoelectric filter. Furthermore, since the end electrodes 9.11 and the like of the element 4 only need to be electrically connected to the respective end electrodes 38 of the boat board 31, the end lead-out electrodes 9.11 can be made smaller and the element 4 can be made smaller. The size of the piezoelectric filter can be reduced.

The present invention is not limited to piezoelectric filters, but can also be applied to other piezoelectric components.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the internal structure of an embodiment of the piezoelectric component according to the present invention, FIG. 2 is an exploded perspective view of the piezoelectric component shown in FIG. 1, and FIG.
A perspective view showing a state in which a conductive adhesive is supplied to the piezoelectric component shown in the figure. Figures 4 (a) and (b) are a plan view and a bottom view of the element, respectively. Figure 5 shows the internal structure of a conventional piezoelectric component. FIG. 6 is a perspective view of the external appearance of the piezoelectric component shown in FIG. 5. 1... Piezoelectric substrate, 4... Element, 9.11
... End extraction electrode, 17... Intermediate extraction electrode, 3I... Support board,
32... Holding part, 33... End lead terminal, 34
...Intermediate lead terminal, 36...Notch, 37...
- Intermediate electrode, 38... End electrode, 41... Conductive adhesive material. Patent applicant Murata Manufacturing Co., Ltd. Agent Patent attorney Aoyama Hajime and two others Figure 2

Claims (1)

[Claims] (1) An element consisting of a piezoelectric substrate having a substantially constant width and having end extraction electrodes and intermediate extraction electrodes at both ends and between them, and a substrate made of an insulating material having dimensions approximately equal to the piezoelectric substrate of this element. A notch is formed at a position corresponding to the intermediate lead-out electrode of the element, and a support substrate on which an intermediate electrode and an end electrode are formed, respectively, are formed at the position of this notch and at both ends. It has a holding part that holds the ends of the overlaid elements and the support substrate, and conduction is established between the end extraction electrode of the element and the end electrode of the support board by means of a conductive adhesive supplied to this holding part. An end lead terminal is drawn out from the holding part in the width direction of the element, and one end is fitted into the notch of the support substrate and conductive to the intermediate lead-out electrode of the element and the intermediate electrode of the support substrate by a conductive adhesive. A piezoelectric component characterized in that it is provided with an intermediate lead terminal that is bonded to the element and is pulled out in the width direction of the element.