JPS62122311A - Piezoelectric resonator with built-in capacitor - Google Patents

Abstract

PURPOSE:To facilitate the external fine adjustment of a capacitance by laminating a capacitor substrate, a piezoelectric substrate and an insulation substrate and locating an electrode formed to one major surface of the capacitor substrate and an external connection electrode of the insulation substrate to the outer face so as to attain miniaturization. CONSTITUTION:The capacitor substrate 2, the piezoelectric substrate 3 and the insulation substrate 4 are laminated and incorporated by applying an adhesives 19 so as not to disturb the vibration of the resonator element E. Connection parts 20-22 are formed and an electrode 5 of the capacitor substrate 2, a lead electrode 10b of the piezoelectric substrate 3 and an electrode 16 of the insulation substrate 4 are connected by the connection part 20. The connection part 21 connects a common electrode 7 on the capacitor substrate 2 and an electrode 17 on the insulation substrate 4, and the connection part 22 connects an electrode 6 of the capacitor substrate 2, a lead electrode 11b of the piezoelectric substrate 3 and an electrode 18 of the insulation substrate 14. The electrodes 5, 7 of the capacitor substrate 2 constitute a capacitor C1 and the electrodes 6, 7 constitute a capacitor C2 and the center part of the piezoelectric substrate 3 constitutes the resonator element E.

Description

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

A piezoelectric resonator with a built-in capacitor is used, for example, in a high-frequency oscillation circuit such as a Colpitts-type oscillation circuit. 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 C1 and C2.

As shown in FIG. 9, the structure of such a conventional piezoelectric resonator is as follows: electrodes 32 are printed on both sides of a single alumina substrate 31, a dielectric material 33 is printed on one main surface of the substrate 31, Two electrodes 34 and 35 are printed on this dielectric material 33.
A rectangular resonator element 36 is soldered onto the electrodes 34 and 35, and these capacitors are connected to the case 3.
7, and connections with the outside are formed on the back surface of the substrate 31 and connected to electrodes 32, 34, and 35, respectively.
It is done by.

Generally speaking, when the oscillation frequency is about 6 MHz or higher, if the resonator element E is of thickness-shear vibration, the thickness of the piezoelectric substrate such as ceramic is increased to one of thickness-shear vibration. 1. There is a problem that the piezoelectric substrate is easily broken during processing. Therefore, when the oscillation frequency is about 6 MHz or more, the resonator element of the piezoelectric resonator should be made thinner. Although it is preferable to use a piezoelectric resonator that vibrates vertically, the conventional piezoelectric resonator structure described above has large dimensions, making it impossible to miniaturize the circuit.

Furthermore, in order to increase the accuracy of the oscillation frequency of the high-frequency oscillation circuit, in the case of the illustrated piezoelectric resonator 1, the capacitance of the capacitor CLC2 must be adjusted with high precision when manufacturing. 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.

Historically, in conventional piezoelectric resonators, each electrode and dielectric 33
Since the dimensions of the capacitor were limited, it was not possible to obtain a large capacitor value.

The present invention has been made in view of these problems, and even if a thick vertical vibration resonator element is used, the increase in dimensions can be minimized, and even after manufacturing. The object of the present invention is to provide a piezoelectric resonator with a built-in capacitor that allows fine adjustment of capacitor capacity.

In order to achieve the above object, the capacitor built-in resonator of the present invention has electrodes formed on both main surfaces, and a capacitor substrate constituting the capacitor, and an electrode formed on one surface of both. A piezoelectric substrate formed to form a resonator element and an insulating substrate having an electrode for external connection formed on at least one main surface are laminated, and one main surface of the capacitor substrate is formed on the outer surface of the laminate. The electrode formed on the insulating substrate and the external connection electrode of the insulating substrate are located therein.

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
It has the circuit configuration shown in FIG. 8, in which the capacitor substrate 2 of FIG. 3, the piezoelectric substrate 3 of FIG. 4, and the insulating substrate 4 of FIG. 5 are laminated. In addition, in Figures 3 to 5, (
(a) shows a plan view of each substrate, and (b) shows a bottom view.

In the capacitor substrate 2, two electrodes 5.6 are provided at the end of one main surface 2a of a rectangular ceramic plate, and one common electrode 7 is provided at the center of the other main surface 2b. They are each formed by printing, and a capacitor is formed by a part of the electrode 5 and a part of the electrode 7 facing each other, and a capacitor is formed by a part of the electrode 6 and a part of the electrode 7. has been done. Furthermore, recesses 8.9 are provided at the ends on the side where the electrodes 5.6 are formed.

The piezoelectric substrate 3 is a top surface 3 of a rectangular piezoelectric ceramic plate.
Electrodes 10 and 11 are formed facing each other at the center of each of the electrodes a 13 b, and constitute a known energy confinement type thick vertical vibration resonator element. For both types l5ii10.11, the extraction electrode part 10ax
The recess 12 is connected to the connection electrode part 10b1 flb formed at the end of the rain surface through the lla, and the recess 12 is formed on the end surface of the substrate 3 on the side where the connection electrode parts tab and ttb are not formed. It is provided.

Insulating substrate 4 which is a rectangular glass epoxy resin insulating plate
In this case, recesses 13.14 are provided at positions corresponding to the four portions 8.9 of the capacitor substrate 2, and recesses 15 are provided at positions corresponding to the recesses 12 of the piezoelectric substrate 3. Three external connection electrodes 16 to 18 are formed on one main surface 4b of the substrate 4, and the electrode 16 is connected to the four parts 14.
, electrode 17 is on the side of recess 15 , electrode 18 is on the side of recess 1
It is also extended and formed on the side surfaces of 3, respectively.

The capacitor substrate 2, piezoelectric substrate 3, and insulating substrate 4 having such a structure are coated with an adhesive 19 so as not to inhibit the vibration of the resonator element E (see FIGS. 6 and 7), and are arranged in this order. are laminated and integrated. Three connection parts 20 to 22 are formed at predetermined locations on the outer surface of this laminate by sputtering and solder dipping, and as shown in FIGS. 6 and 7, the connection parts 20 connect the capacitor substrate 2 to The electrode 5 of the piezoelectric substrate 3, the extraction electrode portion 10b1 of the piezoelectric substrate 3, and the electrode 16 of the insulating substrate 4 are connected, and the common electrode 7 of the capacitor substrate 2 and the insulating substrate 4 are connected by the connecting portion 21.
The connecting portion 22 connects the electrode 17 of the capacitor substrate 2 to the electrode 6 of the capacitor substrate 2 and the lead-out electrode portion 11b1 of the piezoelectric substrate 3.
and the electrode 18 of the insulating substrate 4 are connected. In this embodiment, each substrate has recesses 8.9.12 to 15.
Since this is provided, 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 onto it, there are edges and the film thickness tends to be thin (so even if the edges are rounded by barrel polishing etc. good.

In the thus obtained piezoelectric resonator 1 of this embodiment, the electrodes 5 and 7 of the capacitor substrate 2 constitute the capacitor C1 in FIG. 8, and the electrodes 6 and 7 constitute the capacitor C2. Since the center part of the substrate 3 constitutes a resonator element E, its circuit configuration is as shown in FIG. It corresponds to terminal T2.

Therefore, the piezoelectric resonator 1 configured by laminating in this way
For example, a Kolpin type oscillation circuit can be constructed by connecting the connecting portions 20 to 22 with an external circuit.

First oscillation and recovery - As is clear from the above explanation, in the capacitor built-in resonator of the present invention, a thick vertical vibration resonator element can be used, and the capacitance value of the capacitor can be adjusted. This can be easily achieved by cutting off a part of the externally exposed electrode (in the embodiment described above, electrode 5 or electrode 6) by laser trimming or the like, and furthermore, miniaturization is possible. It is possible.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention, FIG. 2 is a perspective view thereof, FIG. 3(a) is a plan view of a capacitor board, and FIG.
FIG. 4(b) is a bottom view of the piezoelectric substrate, FIG. 4(b) is a bottom view of the piezoelectric substrate, FIG. 5(a) is a plan view of the insulating substrate, and FIG. b) is its bottom view, Fig. 6 is the second
An enlarged end view taken along line A-A in the figure, Figure 7 is B- in Figure 2.
FIG. 8 is an enlarged end view taken along line B, FIG. 8 is a circuit diagram of a piezoelectric resonator with a built-in capacitor, and FIG. 9 is an explanatory diagram of the structure of a conventional piezoelectric resonator. 1... Piezoelectric resonator, 2... Capacitor board, 3...
- Piezoelectric λλ plate, 4... Insulating substrate, C1, C2... Capacitor, E... Resonator element. Patent applicant Murata Manufacturing Co., Ltd. Figure 1 Figure 3 (a) (b) 4a 15 40
1) Figure 6 Figure 7

Claims (1)

[Claims] A capacitor substrate with electrodes formed on both main surfaces to form a capacitor, a piezoelectric substrate with electrodes formed on both main surfaces to form a resonator element, and an electrode for external connection formed on at least one main surface. insulating substrates are stacked, and an electrode formed on one main surface of the capacitor substrate and an external connection electrode of the insulating substrate are located on the outer surface of the laminate. A piezoelectric resonator with a built-in capacitor.