JPS62122312A - Piezoelectric resonator built-in capacitor - Google Patents

Abstract

PURPOSE:To attain the minute adjustment of the capacitance and the miniaturization by providing a capacitor substrate constituting a capacitor whose electrodes are formed on both major surfaces, a resonator element, an insulation plate supporting it and an insulation substrate formed with electrodes. CONSTITUTION:The capacitor substrate 2, the insulation spacer 3 supporting the resonator element 4, and the insulation substrate 5 are laminated sequentially to form three connection parts 27-29. The connection part 27 connects an electrode 7b of the capacitor substrate 2 and an electrode 17 of the insulation substrate 5, the connection part 28 connects an electrode 6 of the capacitor substrate 2 and an electrode 19 of the insulation substrate 5 and the connection part 29 connects an electrode 8b of the capacitor substrate 2 and an electrode 18 of the insulation substrate 5. In the piezoelectric resonator 1, the electrodes 6, 7 of the capacitor substrate 2 constitute a capacitor C1 and the electrodes 6, 8 constitute a capacitor C2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric resonator with a built-in capacitor used in a high frequency oscillation circuit or the like.

Conventional piezoelectric resonators with built-in Δ11 capacitors have been used, for example, in high-frequency oscillation circuits such as Colpitts-type oscillation circuits. An example of such a piezoelectric resonator is one having a circuit configuration shown in FIG. This piezoelectric resonator 1 has one resonator element E and two capacitors CI and C2.

In general, if the oscillation frequency is about 6 MHz or less, unless the resonator element E is of thickness-shear vibration, the thickness dimension will become too large and the electrical characteristics will deteriorate. The structure of such a conventional piezoelectric resonator that uses thickness-shear vibration is as shown in FIG. A conductive body 33 is printed on the main surface, and two electrodes 3 are placed on this conductive body 33.
4.35 to form two capacitors and electrode 3
A rectangular resonator element 36 is soldered onto the 4.35, and these are covered with a case 37. Connections with the outside are formed on the back surface of the substrate 31, and the electrode 3
2.34.35 and electrodes 32a134 connected respectively
This is done by a135a.

, [l °' 1,11] In order to increase the accuracy of the oscillation frequency of a high frequency oscillation circuit in which such a piezoelectric resonator 1 is used, capacitors CI, C
The piezoelectric resonator 1 must be manufactured by adjusting the capacitance of the piezoelectric resonator 2 with high precision. Fine adjustment of this capacitor capacity can be performed by adjusting the electrode area by laser trimming or the like. However, in the conventional piezoelectric resonator as described above, the capacitors C1 and C2 are covered by the resonator element 36 and housed in the case 37, so the capacitors cannot be removed after manufacturing. Since it is not possible to finely adjust the capacitance, it has not been possible to increase the accuracy of the capacitor capacitance. In addition, in conventional piezoelectric resonators, the dielectric material and the dimensions of each electrode and dielectric 23 are limited, making it impossible to obtain a large capacitance value.Furthermore, the overall size is large, making the circuit compact. could not be converted into

The present invention has been made in view of these problems, and provides a piezoelectric resonator with a built-in capacitor that allows for easy fine adjustment of capacitor capacity even after manufacturing, and that can be made smaller. is intended to provide.

In order to achieve the above object, the capacitor built-in resonator of the present invention has electrodes formed on both main surfaces, and supports the capacitor substrate, the resonator element, and the resonator element that constitute the capacitor. The capacitor substrate, the insulating spacer, and the insulating substrate are laminated in this order, and the outer surface of the laminate includes a plate-shaped insulating spacer and an insulating substrate having an electrode for external connection formed on at least one main surface. It is characterized in that an electrode formed on one main surface of the capacitor substrate and an external connection electrode of the insulating substrate are located.

FIG. 1 is an exploded perspective view of an embodiment of a piezoelectric resonator with a built-in capacitor according to the present invention. The piezoelectric resonator 1 of this embodiment is
The circuit has the circuit configuration shown in FIG. 9, and the fourth
The insulating spacer 4 shown in the figure and the insulating substrate 5 shown in FIG. 6 are laminated.

In the capacitor substrate 2, one common electrode 6 is provided at the center of one main surface 2a of the rectangular ceramic plate, and two electrodes 7.8 are provided at the ends of the other main surface 2b. They are each formed by screen printing, and a part of electrode 6 and electrode 7 facing each other constitute a capacitor, and a part of electrode 6 and electrode 8 constitute another capacitor. . The electrodes 7.8 are connected to connection electrode parts 7b and 8b formed at the ends of the main surface 2b, respectively, via extraction electrode parts 7a18a.

Furthermore, a recess 9 is provided at the end of the intermediate portion of the substrate 2 .

A rectangular window 10 is formed in the center of the insulating spacer 3, which is a rectangular insulating plate made of glass epoxy resin. A matched recess 11 is provided in each case. Further, a recess 1 is provided at a position corresponding to the four parts 9 of the capacitor board 2.
3, and a recess m12.14 is provided at the end of the capacitor substrate 2 on the side corresponding to the electrode 7b18b.

A conductive portion is formed between the upper surfaces of the screen of these recesses 12 to 14 by through-hole plating.

The resonator element 4 is a known energy confinement type thickness shear vibration resonator formed such that electrodes 15 and 16 partially face the upper surfaces 4a and 4b of a rectangular piezoelectric ceramic plate.

The insulating substrate 5 is also a rectangular insulating plate made of glass epoxy resin, and electrodes 17 are provided at both ends of one main surface 5a of the substrate 5.
．． 18 are formed respectively, and these electrodes 17.
18 is also formed extending to the other main surface 5b via the recess 20.22. Further, an electrode 19 is formed in the center of the other main surface 5b, and a portion of this electrode 19 is also formed on the side surface of the recess 21 provided corresponding to the recess 213.

To assemble the piezoelectric resonator 1 of this embodiment, which is composed of the above-mentioned parts, first, the insulating substrate 5 and the insulating spacer 3 are bonded together with an adhesive 23 (see FIGS. 7 and 8).

Next, both light side sides of the resonator element 4 are covered with insulating spacers 3.
The resonator element 4 is fitted into the recess 11 of the window 10.
is accommodated in the insulating spacer 3, and the conductive paste 2
4 connects the electrode 15 and the electrode 17 of the insulating substrate 5, and the electrode 16 and the electrode 18. Subsequently, the capacitor substrate 2 and the insulating spacer 3 are bonded together using the adhesive 25, and the electrode 7b and the electrode 1 are bonded together using the same (conductive paste 24).
5 to connect the electrode 8b and the electrode 16, respectively.

In reality, after bonding one mother insulating spacer on which a plurality of insulating spacers 3 are integrally formed to one mother insulating substrate on which a plurality of insulating substrates 5 are integrally formed, the window 10 of each insulating spacer 3 is bonded. Both light side sides of the resonator element 4 are fitted into the recesses 11 of the resonator element 4, and predetermined connections are made with conductive paste. An integrated laminate is obtained by adhering to insulating spacers. After that, this laminate is vertically
A plurality of piezoelectric resonators 1 are obtained by cutting horizontally.

In this way, sputtering, soldering, and pinging are applied to predetermined locations on the outer surface of the integrated laminate in which the capacitor substrate 2, the insulating spacer 3 supporting the resonator element 4, and the insulating substrate 5 are laminated in order. As shown in FIG. 7 and FIG. connected, connection part 2
8 connects the electrode 6 of the capacitor board 2 and the electrode 19 of the insulating board 5, and the connection part 29 connects the capacitor board 2.
The electrode 8b and the electrode 18 of the insulating substrate 5 are connected. In this embodiment, the recesses 9.12 to 14.20
22, the connection between each electrode can be made more reliably. Note that when sputtering is performed on a predetermined location on the outer surface of the laminate and the solder is attached on top of the sputtering, the film thickness tends to be thinner due to the presence of scratches, so barrel polishing is performed to round the edges. Good too.

In addition, since the resonator element 4 is supported by the recess 11 of the window 10 of the insulating spacer 3, the position of the resonator element 4 may shift during assembly, inhibiting the vibration of the resonator element and deteriorating its characteristics. Deterioration is prevented.

In the thus obtained piezoelectric resonator 1 of this example,
Electrodes 6 and 7 of the capacitor substrate 2 constitute a capacitor C1 in FIG. 9, electrodes 6 and 8 constitute a capacitor C2, and the resonator element 4 corresponds to the resonator element E in FIG. Therefore, the circuit configuration is as shown in FIG. 9, where the connection part 27 is connected to the terminal T1 in FIG.
9 corresponds to terminal T2. Therefore, the piezoelectric resonator 1 configured by stacking in this way has these connection parts 27
29 can be connected to an external circuit to configure, for example, a Colpitts type oscillation circuit.

As is clear from the above explanation, in the piezoelectric resonator with a built-in capacitor of the present invention, the capacitance value of the capacitor can be adjusted by using the externally exposed electrode (as described in the above embodiment). This can be easily done by cutting off a part of the electrode 6) by laser trimming or the like, and it is also possible to reduce the size of the electrode 6).

[Brief explanation of drawings]

1 is an exploded perspective view of one embodiment of the present invention, FIG. 2 is a perspective view thereof, FIG. 3(a) is a plan view of a capacitor board, FIG. 3(b) is a bottom view of the capacitor board, 5(a) is a plan view of the resonator element, FIG. 5(b) is a bottom view of the resonator element, and FIG. 6(a) is a plan view of the insulating spacer.
) is a plan view of the insulating substrate, FIG. 7(b) is a bottom view of the insulating substrate, FIG. 7 is an enlarged end view along line A-A in FIG. 9 is a circuit diagram of a piezoelectric resonator with a built-in capacitor, and FIG. 10 is an explanatory diagram of the structure of a conventional piezoelectric resonator. ■... Piezoelectric resonator, 2... Capacitor board, 3...
・Insulating spacer, 4... Resonator element, 5...
Insulating substrate, C1, C2... capacitor, E... resonator element. Patent applicant: Murata Manufacturing Co., Ltd. Figure 1, Figure 2, Figure 4, Figure 4, Figure 7, Figure 8.

Claims (1)

[Claims] Electrodes were formed on both main surfaces, and a capacitor substrate constituting the capacitor, a resonator element, a plate-shaped insulating spacer that supported the resonator element, and an electrode for external connection were formed on at least one main surface. An insulating substrate is provided, the capacitor substrate, an insulating spacer, and an insulating substrate are laminated in this order, and an electrode formed on one main surface of the capacitor substrate and an external connection electrode of the insulating substrate are provided on the outer surface side of the laminated body. A piezoelectric resonator with a built-in capacitor, characterized in that the piezoelectric resonator has a built-in capacitor.