JPH04103015U - Piezoelectric components with built-in load capacitance - Google Patents

Abstract

(57) [Summary] [Purpose] To easily obtain a piezoelectric component with built-in load capacitance, which is a piezoelectric component that configures an oscillation circuit in combination with an amplifier circuit and has a high oscillation frequency accuracy. [Configuration] Grounding electrodes 2 and 2 are provided on the first main surface of the dielectric substrate 1.
Two signal input/output electrodes 3 and 4 are formed, and a second signal input/output electrode 3 and 4 are formed.
An auxiliary electrode 5 that generates capacitance between the grounding electrode 2 and the signal input/output electrodes 3 and 4 is formed on the main surface, and a piezoelectric element vibrating through thickness shear is used to generate signals on the first main surface of the dielectric substrate. Connect between input/output electrodes 3 and 4. [Operation] By partially cutting the auxiliary electrode 5, the capacitance between the grounding electrode 2 and the signal input/output electrodes 3 and 4 is corrected, thereby finely adjusting the oscillation frequency.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea has a built-in load capacitor that can be combined with an amplifier circuit to form a rectangular wave oscillation circuit. Regarding type piezoelectric components.

0002

[Conventional technology]

For example, Figure 7 shows a circuit that generates a rectangular wave signal with a constant frequency as a clock signal. An oscillation circuit as shown in is constructed. In the figure, X uses piezoelectric ceramics. Piezoelectric elements, CL1 and CL2 are load capacitances, and IC is an amplifier circuit. This way With such a circuit configuration, the resonant frequency and load capacitances CL1 and CL2 of the piezoelectric element A rectangular wave signal with a frequency determined by the capacitance of is generated.

0003 In order to make the above-mentioned oscillation circuit very inexpensive and small, piezoelectric element X and load capacitance C A piezoelectric component with built-in load capacity that integrates L1 and CL2 (inside the dashed line in Figure 7) (consisting of a single part) are used.

0004 The conventional structure of the piezoelectric component with built-in load capacity is shown in FIGS. 9 to 11.

[0005] FIG. 9 is a perspective view showing the internal structure of the component. It is composed of a dielectric substrate 1 and a piezoelectric element X.

[0006] FIG. 10 is a perspective view of the dielectric substrate 1, with a grounding electrode 2 on one main surface thereof. Two signal input/output electrodes 3 and 4 are formed.

[0007] FIG. 11 is a cross-sectional view of the dielectric substrate, and as shown in the figure, the grounding electrode 2 and two Capacitances CL1 and CL2 are formed between the signal input and output electrodes 3 and 4, respectively. Ru.

[0008] As shown in FIG. 9, there are two signal input/output ports on the electrode forming surface side of the dielectric substrate 1. A piezoelectric element X is soldered to the electrodes 3 and 4.

[0009] With the above configuration, the piezoelectric component with built-in load capacity shown within the dashed line in Figure 7 is constructed. It is.

0010

[Problem that the idea aims to solve]

The conventional piezoelectric components with built-in load capacitance mentioned above are extremely inexpensive and compact. Although it has the feature of being able to provide parts, it is possible to construct an oscillation circuit as shown in Figure 7. The actual oscillation frequency is greatly influenced by the variation in the resonance frequency of the piezoelectric element In order to keep the frequency within the desired frequency tolerance, the piezoelectric element It is necessary to measure the resonance frequency and select piezoelectric elements with the desired resonance frequency. there were. As a result, piezoelectric elements that were not selected were defective. Moreover, dielectric When a piezoelectric element is connected to the board to form a piezoelectric component with built-in load capacitance, In order for the oscillation frequency to fall within the target tolerance, the static load capacitances CL1 and CL2 must be Variations in capacitance must also be considered, and the permissible range of resonance frequency of piezoelectric element becomes extremely narrow. As a result, highly accurate piezoelectric components with built-in load capacitance can be manufactured with high yield. It was difficult to build.

[0011] The purpose of this invention is to make it possible to adjust the value of the load capacitance formed on the dielectric substrate. The object of the present invention is to provide a piezoelectric component with built-in load capacitance that solves the above-mentioned problems.

0012

[Means to solve the problem]

The piezoelectric component with built-in load capacitance of this invention has a grounding electrode on the first main surface of the dielectric substrate. , connect two signal input/output electrodes that generate capacitance with this grounding electrode. A capacitance is formed between the grounding electrode and the signal input/output electrode on the second main surface. A piezoelectric element is formed on the first main surface of the dielectric substrate. and is connected between the two signal input/output electrodes.

[0013]

[Effect]

In the piezoelectric component with built-in load capacitance of this invention, the first main surface of the dielectric substrate is provided with a grounding voltage. A pole and two signal input/output electrodes are formed respectively, and a second main electrode of the dielectric substrate is formed. There is an auxiliary capacitor on the surface that creates capacitance between the grounding electrode and the signal input/output electrode. poles are formed. Further, the piezoelectric element is arranged on the first main surface of the dielectric substrate. It is connected between the two signal input/output electrodes. It is configured as above. between the grounding electrode and the two signal input/output electrodes, both directly and via an auxiliary electrode. A capacitance is formed in each case. For grounding formed on the first main surface of the dielectric substrate The electrode and two signal input/output electrodes are covered by a piezoelectric element, but the first electrode on the dielectric substrate The auxiliary electrodes formed on the second main surface are exposed. Therefore, pressure is applied to the dielectric substrate. With the electrical element connected, the auxiliary electrode can be connected, for example by partially cutting it. The capacitance between the ground electrode and the signal input/output electrode can be adjusted. this thing Therefore, the oscillation frequency can be adjusted without changing the piezoelectric element itself.

[0014] Therefore, the piezoelectric element itself has a relatively wide allowable range of resonance frequency. The overall yield can be significantly improved.

[0015]

【Example】

Figures 1 to 4 show the structure of the main parts of a piezoelectric component with built-in load capacity, which is an embodiment of this invention. Shown below.

[0016] FIG. 1 is a perspective view showing the internal structure of the component, where 1 is a dielectric substrate, X is a piezoelectric element, 6, 7, and 8 are lead terminals, respectively. Here, the piezoelectric element X has the same thickness as the conventional one. This uses the sliding vibration mode.

[0017] FIG. 2 is a perspective view of the dielectric substrate viewed from the first main surface side. The first main body of the dielectric substrate 1 On the surface, there are a grounding electrode 2 and a signal input/output electrode 3, similar to the conventional example shown in FIG. , 4 respectively.

[0018] FIG. 3 is a plan view (bottom view) of the dielectric substrate viewed from the second main surface side. In the same figure As shown, the position facing the grounding electrode 2 and the two signal input/output electrodes 3 and 4 An auxiliary electrode 5 is formed on.

[0019] FIG. 4 is a central sectional view of the dielectric substrate. As shown in the figure, the grounding electrode 2 and the signal Capacitances C2 and C4 are formed between the input and output electrodes 3 and 4, respectively, and the auxiliary electrode 5 and the grounding electrode 2 and the signal input/output electrodes 3 and 4, there are capacitances C3 and C. 1 and C5 are formed, respectively.

[0020] A circuit diagram of the dielectric substrate shown in FIG. 4 is shown in FIG. 5. here 6,7 , 8 correspond to the leads 6, 7, and 8 shown in FIG. 1, respectively. This circuit diagram is shown in Figure 6. For example, the grounding lead terminal 7 and the signal input/output terminal The capacitance between 6 and 6 can be expressed as C2+ (C1C3/(2C1+C3)).

[0021] Now, in the basic oscillation circuit shown in Figure 7, the values of load capacitances CL1 and CL2 are When both are changed at the same rate, the oscillation frequency shifts as shown in FIG.

[0022] As shown in FIG. 1, the dielectric substrate configured as described above has two With the piezoelectric element X connected between the two signal input/output electrodes 3 and 4, its oscillation frequency is Depending on the deviation from the measured and desired oscillation frequency, a part of the auxiliary electrode 5 (for example, Fig. 3 Cut the shaded area). As a result, the capacitance of C1 and C2 decreases, and the load Capacitances CL1 and CL2 decrease, and the oscillation frequency increases. Therefore, usually the auxiliary electrode 5 is made slightly larger and the oscillation frequency is set slightly lower than the target value before modification. By setting the auxiliary electrode to the desired circumference without slight machining or modification, A piezoelectric component that falls within the wavenumber tolerance is obtained.

[0023]

[Effect of the idea]

According to this idea, a piezoelectric element is connected to a dielectric substrate that forms a load capacitance. Since the value of the load capacitance can be adjusted depending on the state, the resonant frequency of the piezoelectric element itself can be adjusted. Piezoelectric components with built-in load capacitance that have the desired oscillation frequency without narrow selection can be easily manufactured. In addition, the load capacity has excellent oscillation frequency accuracy. Built-in piezoelectric components can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the structure of a main part of a piezoelectric component with built-in load capacity according to an embodiment of the present invention.

FIG. 2 is a perspective view of the dielectric substrate used in the piezoelectric component with built-in load capacitance, viewed from the first main surface side.

FIG. 3 is a plan view of the dielectric substrate viewed from the second main surface side.

FIG. 4 is a sectional view taken along line XX′ in FIG. 2;

FIG. 5 is a circuit diagram of a dielectric substrate.

FIG. 6 is a circuit diagram of a dielectric substrate.

FIG. 7 is a circuit diagram of a general rectangular wave oscillation circuit.

8 is a diagram showing the characteristics of oscillation frequency shift when changing CL1 and CL2 in FIG. 7. FIG.

FIG. 9 is a perspective view showing the structure of the main part of a conventional piezoelectric component with built-in load capacity.

FIG. 10 is a perspective view of a dielectric substrate used in a conventional piezoelectric component with built-in load capacitance.

FIG. 11 is a sectional view taken along line XX' in FIG. 10.

Claims (1)

[Scope of utility model registration request] [Claim 1] A grounding electrode on the first main surface of the dielectric substrate;
Two signal input/output electrodes that generate capacitance with this grounding electrode are formed respectively, and capacitance is generated between the grounding electrode and the signal input/output electrode on the second main surface. A piezoelectric component with built-in load capacitance, wherein an auxiliary electrode is formed to provide a load capacitance, and a piezoelectric element is connected between the two signal input/output electrodes on the first main surface of the dielectric substrate.